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  • Role of electronic and magnetic interactions in defect formation and anomalous diffusion in δ-Pu
    J. Nucl. Mater. (IF 2.547) Pub Date : 2020-01-26
    Sarah C. Hernandez; Franz J. Freibert; Blas P. Uberuaga; John M. Wills

    Previous experimental work has shown self-irradiation in Pu solids produces point defect populations that correlate with increases in local disorder, long-range structural changes, induced magnetic moments, and other thermo-physical property changes. Thermally activated kinetic processes drive these defects to diffuse and interact toward either damage evolution or lattice recovery. Using DFT and cNEB, as implemented in VASP, migration barriers for mono-vacancy and split-interstitial diffusion and Frenkel pair recombination were calculated in fcc δ-Pu. The results indicate the migration barrier of a monoclinic mono-vacancy is lower when compared to the migration barrier of a tetragonal split-interstitial in δ-Pu, contrary to typical fcc metal point defect migration. This fundamentally different diffusion mechanism is a result of local symmetry breaking induced by electronic and magnetic interactions leading to the development of Pu–Pu short bonds (<3.0 Å) within a many-atom complex defect forming and migrating. The migration of the monoclinic mono-vacancy maintains short bonds with anti-parallel spins throughout the transition; whereas, during the migration transition state for the tetragonal split-interstitial, formation of short bonds with parallel spins and a spin-flip of the migrating Pu interstitial occurs. The associated energy cost is reflected in an increase in the migration barrier energy. Frenkel pair recombination is not spontaneous at 0K, but correlates with magnetic moment interactions, leading to an energy barrier for recombination. From these results, it is concluded that migration of defects in unalloyed δ-Pu are highly dependent on the electronic and magnetic interactions that induce associated low-symmetry structures and consequently influence the diffusional properties. Typical fcc defect diffusion mechanisms do not apply to the monoclinic mono-vacancy and tetragonal split-interstitial in the complex 5f δ-Pu system suggesting that the experimental observation of radiation damage induced localized magnetic moments and anomalous diffusion properties measured in δ-Pu could be understood in terms of defect kinetics and interactions.

    更新日期:2020-01-26
  • The HICU PIE results of EU ceramic breeder pebbles: Tritium release properties
    J. Nucl. Mater. (IF 2.547) Pub Date : 2020-01-26
    J.M. Heuser; M.H.H. Kolb; R. Rolli; H.-C. Schneider; R. Knitter; M. Zmitko

    The former EU reference lithium orthosilicate based breeder pebbles were exposed to neutron irradiation in the HICU (High neutron fluence Irradiation of pebble staCks for fUsion) experiment to test their stability and tritium release properties under DEMO relevant conditions. The samples, varying by three different Li-6 contents, were exposed to irradiation at two different temperatures and the pebbles were either pre-compacted or not. This second part of the post-irradiation examination is focussing on the tritium release behaviour of the ceramic breeder pebbles. The irradiation temperature has the strongest influence on the tritium release behaviour. The tritium inventory is significantly higher for samples that were irradiated at low temperatures. A clear trend regarding higher release rates with increasing Li-6 content was not observed. Tritium is released in a multi-staged process as HTO, HT or corresponding fragments. Fits based on the Wigner-Polanyi equation suggest that recombination reactions of tritium with adsorbed species on the pebble's surface play the dominant role in the release process. However, the probability for the recombination of two adsorbed T-species on the surface seems to be too low, as no reliable signal for T2 was detected.

    更新日期:2020-01-26
  • Oxidation and passivation of U(AlxSi1-x)3 alloy at elevated temperatures
    J. Nucl. Mater. (IF 2.547) Pub Date : 2020-01-25
    S. Cohen; M. Matmor; M. Vaknin; G. Rafailov; O. Appel; L. Shelly; N. Shamir; S. Zalkind

    The surface composition of U(AlxSi1-x)3 alloy (x = 0.57) and its interactions with oxygen, at elevated temperatures, were studied, utilizing Auger electron spectroscopy, X-Ray photoelectron spectroscopy and direct recoil spectrometry. Heating the alloy in ultra-high vacuum, results in aluminum (and some silicon) segregation to the surface, forming, above 700 K, a ∼0.6 nm self-assembly capping layer. Exposing the surface alloy to oxygen, at temperatures up to 500 K, causes oxidation of the uranium and the aluminum components, while silicon is only slightly oxidized. Above 600 K, only the aluminum segregated overlayer is oxidized, forming a passivation layer that inhibits further oxidation of the alloy.

    更新日期:2020-01-26
  • Synthesis and characterization of zirconolite-sodium borosilicate glass-ceramics for nuclear waste immobilization
    J. Nucl. Mater. (IF 2.547) Pub Date : 2020-01-25
    Hanzhen Zhu; Fu Wang; Qilong Liao; Yongchang Zhu

    Zirconolite-sodium borosilicate glass-ceramics were successfully prepared via slow-cooling methods, and the crystallization, microstructure and aqueous durability have been investigated with powder X-ray diffraction (XRD), backscattered scanning electron microscopy and energy dispersive spectroscopy (BSE-EDS), Raman spectroscopy and ASTM Product Consistency Test leaching method. The results show that the main crystalline phase in the prepared glass-ceramics is strip-shaped zirconolite phase and the quantitative fraction of the zirconolite phase is about 30 wt%, the chemical composition of zirconolite crystals grown from a glass matrix is determined by Rietveld refinement to be Ca0.93Zr0.76Ce0.31Ti1.95Al0.05O7 and 84.53% Ce are incorporated in zirconolite crystals. Moreover, the aqueous durability test shows the low normalized leaching rates of Si (LRSi), Ca (LRCa) and Ce (LRCe) of the glass-ceramics, and LRSi, LRCa and LRCe are about 4 × 10−4, 1 × 10−4 and 8 × 10−7 g m−2 d−1, respectively after 56 leaching days. The obtained conclusions provide useful information for the immobilization of high-level radioactive wastes by using borosilicate glass-ceramic as potential matrix through one-step method.

    更新日期:2020-01-26
  • Demonstration of 2D MXene Memristor: Stability, Conduction Mechanism, and Synaptic Plasticity
    Mater. Lett. (IF 3.019) Pub Date : 2020-01-25
    Nan He; Xinwei Liu; Fei Gao; Qiangqiang Zhang; Miaocheng Zhang; Yu Wang; Xinyi Shen; Xiang Wan; Xiaojuan Lian; Ertao Hu; Lin He; Jianguang Xu; Yi Tong

    As the emerging device for neuromorphic applications, memristive device is arguable regarded as the most promising candidate to emulate biological synapse due to its specific analog behaviors and various plasticities. Nevertheless, the stability of memristive device remains an extreme challenge limiting its practical applications. In this work, two-dimensional (2D) material MXene is introduced into TiN/Cu/SiO2/TiN device as an insertion layer. The existence of MXene leads the memristor to perform more stable resistance states. The dominant conduction mechanisms responsible for stable resistance states are consistent with space charge limited and Ohmic conductions. In addition, synaptic plasticities, including long-term potentiation and depression, have been successfully mimicked by MXene memristors.

    更新日期:2020-01-26
  • Mussel-inspired construction of Ti6Al4V-hydrogel artificial cartilage material with high strength and low friction
    Mater. Lett. (IF 3.019) Pub Date : 2020-01-25
    Kai Chen; Siyu Liu; Xiaofang Wu Data; Fengyan Wang; Guangyan Chen; Xuehui Yang; Linmin Xu; Jianwei Qi; Yong Luo; Dekun Zhang

    Based on the adhesion mechanism of polydopamine, the mussel-inspired hydrogel was prepared on the surface of the Ti6Al4V (Ti) with polydopamine (PDA), polyvinyl alcohol (PVA), hydroxyapatite (HA) and polyacrylic acid (PAA) as raw materials in this study, and the Ti-hydrogel artificial cartilage material was constructed. The hydrogel exhibited a tensile strength of 11.76 MPa, an elongation of 988.76%, and a creep deformation of only 0.035 mm under a 20 N load. The friction coefficient of the Ti6Al4V-hydrogel (Ti-hydrogel) artificial cartilage material decreased and the friction performance was improved. After the substrate was modified by the PDA, the bonding strength of the substrate to the hydrogel up to 6.64 MPa. Therefore, the mussel-inspired hydrogel is an ideal high-strength biomimetic cartilage material.

    更新日期:2020-01-26
  • 更新日期:2020-01-26
  • Surfactant Mediated TiO2 Photoanodes and Cu2ZnSnS4 Counter Electrodes for High Efficient Dye Sensitized Solar Cells
    Mater. Lett. (IF 3.019) Pub Date : 2020-01-25
    Jitendra P. Sawant; Rohidas B. Kale

    Highly crystallized kesterite Cu2ZnSnS4 (CZTS) nanoparticles with an energy band gap of 1.54 eV and desired elemental compositions were prepared by hydrothermal method. CZTS thin films were prepared on titanium tetrachloride (TiCl4) treated fluorine doped tin oxide (FTO) substrate by doctor blade coating method. Morphological developments of hydrothermal synthesized, sodium dodecyl sulfate (SDS) mediated, TiO2 nanostructured thin films on TiCl4 treated FTO substrate were investigated. The CZTS/FTO counter electrodes (CSs) and TiO2 nanostructured photoanodes were employed in dye sensitized solar cells (DSSCs). DSSCs device with power conversion efficiency of 6.24% have been fabricated. The TiCl4 treated CZTS CEs and SDS mediated TiO2 nanostructure photoanodes provides suitable electrodes for low cost and high efficient dye sensitized solar cells.

    更新日期:2020-01-26
  • Colorimetric/Fluorescent Dual Channel Sensitive Coating for Early Detection of Copper Alloy Corrosion
    Mater. Lett. (IF 3.019) Pub Date : 2020-01-25
    Huai Wang; Yong Fan; Limei Tian; Jie Zhao; Luquan Ren
    更新日期:2020-01-26
  • A DNA vaccine that encodes an antigen presenting cell-specific heterodimeric protein protects against cancer and influenza
    Mol. Ther. Methods Clin. Dev. (IF 4.875) Pub Date : 2020-01-25
    Ranveig Braathen; Heidi Cecilie Larsen Spång; Daniëla Maria Hinke; Jana Blazevski; Sonja Bobic; Even Fossum; Bjarne Bogen

    Immunogenicity of DNA vaccines can be increased by constructing the DNA in such a way that it encodes secreted homodimeric fusion proteins that target antigen presenting cells (APC). We have here developed novel APC-targeting vaccine molecules with an increased flexibility due to introduction of a heterodimerization motif. The heterodimeric proteins permit four different fusions within a single molecule, thus allowing expression of two different APC-targeting moieties and two different antigens. Two types of heterodimeric fusion proteins were developed that employed either the ACID/BASE- or the Barnase/Barstar-motifs, respectively. The ACID/BASE heterodimeric vaccines conferred protection against challenges with either influenza virus or tumor cells in separate preclinical models. The ACID/BASE-motif was flexible since a large number of different targeting moieties and antigens could be introduced with maintenance of specificity, antigenicity and secretion. APC-targeting ACID/BASE vaccines expressing two different antigens induced antibody and T cell responses against either of the two antigens. Heterodimeric ACID/BASE DNA vaccines were of approximately the same potency as previously reported homodimeric DNA vaccines. The flexibility and potency of the ACID/BASE format suggest that it could be a useful platform for DNA vaccines that encode APC-targeting fusion proteins.

    更新日期:2020-01-26
  • A triple-regulated oncolytic adenovirus carrying microRNA-143 exhibits potent antitumor efficacy in colorectal cancer
    Mol. Ther. Oncolytics (IF 5.710) Pub Date : 2020-01-25
    Qifeng Luo; Hongming Song; Xiaochong Deng; Jiayi Li; Wei Jian; Junyong Zhao; Xueyu Zheng; Shiva Basnet; Haiyan Ge; Twingle Daniel; Bin Xu; Lin Fang

    The Cancer targeting Gene-Virotherapy might be a useful strategy for the treatment of cancer because it could combine the advantages of both gene therapy and virotherapy. This study aimed to construct a triple-regulated oncolytic adenovirus Ad-RGD-Survivin-ZD55-miR-143 carrying the therapeutic gene miR-143 and evaluate its possible antitumor effect in colorectal cancer. We observed that miR-143 was lowly expressed in patients with colorectal cancer. The up-regulation of miR-143 could inhibit cell proliferation and induce cell apoptosis by targeting KRAS in colorectal cancer cells. Then, a triple-regulated oncolytic adenovirus Ad-RGD-Survivin-ZD55-miR-143 was successfully constructed in this study. Cells infected with Ad-RGD-Survivin-ZD55-miR-143 could inhibit cell proliferation, suppress cell migration and invasion, arrest cells at the G1 phase and induce cellular apoptosis. At the same time, Ad-RGD-Survivin-ZD55-miR-143 decreased the expression of PARP-1 and KRAS protein in vitro. In a HCT116 xenograft model, intratumoral injection of Ad-RGD-Survivin-ZD55-miR-143 resulted in reduced tumor growth. Furthermore, Ad-RGD-Survivin-ZD55-miR-143 induced apoptosis and decreased expression level of KRAS in HCT116 xenograft cells. Our results suggested that Ad-RGD-Survivin-ZD55-miR-143 produced a strong antitumor effect by targeting KRAS and that this strategy could broaden the therapeutic options for treating colorectal cancer.

    更新日期:2020-01-26
  • Wif1 suppresses the generation of suprabasal cells in acanthotic skin and growth of basal cell carcinomas upon forced overexpression
    J. Invest. Dermatol. (IF 6.290) Pub Date : 2020-01-25
    Marco Becker; Julia Bauer; Joanna Pyczek; Simone König; Anna Müllen; Hanna Rabe; Michael P. Schön; Anja Uhmann; Heidi Hahn

    We analyzed the role of Wnt inhibitory factor 1 (Wif1) in normal and acanthotic epidermis of 12-O-tetradecanoylphorbol-13-acetate (TPA) or all-trans-retinoic acid (ATRA)-treated and basal cell carcinoma (BCC)-bearing mice. Wif1 protein is located in the follicular infundibulum and interfollicular epidermis (IFE) in murine back skin. Within the hyperplastic epidermis of TPA- or ATRA-treated or BCC-bearing murine skin, Wif1 and K10 overlap in Ki67neg suprabasal layers, while basal epidermal layers expressing Ki67, and BCCs expressing Wif1 mRNA, are free of Wif1 protein. This is similar in human skin, with the exception that WIF1 protein is found in single Ki67neg basal epidermal cells in normal skin and additionally in Ki67+ cells in acanthotic skin. Wif1-deficiency enhances acanthosis of the BCC-associated epidermis, which is accompanied by an increase of Ki67+ and of Sca-1+ basal cells. Wif1 overexpression in allografted BCC-derived keratinocytes prevents growth and keratinization, involving enhanced phosphorylation of PKC and Erk1 and arguably factors secreted by the in vivo environment. Together, Wif1 protein marks suprabasal layers in the normal IFE. It is also present in the epidermis overlaying BCCs where it diminishes proliferation of basal cells and production of differentiating suprabasal cells. In addition, Wif1 can prevent proliferation and keratinization of BCC-related keratinocytes.

    更新日期:2020-01-26
  • Efficient delivery of antisense oligonucleotides using bioreducible lipid nanoparticles in vitro and in vivo
    Mol. Ther. Nucl. Acids (IF 5.919) Pub Date : 2020-01-25
    Liu Yang; Feihe Ma; Fang Liu; Jinjin Chen; Xuewei Zhao; Qiaobing Xu
    更新日期:2020-01-26
  • Discovering Cancer-related miRNAs from miRNA-target Interactions by Support Vector Machines
    Mol. Ther. Nucl. Acids (IF 5.919) Pub Date : 2020-01-25
    Cong Pian; Shanjun Mao; Jiali Yang; Guangle Zhang; Jin Du; Suet Yi Leung; Yuanyuan Chen; Xiaodan Fan

    miRNAs have been shown to be closely related to cancer progression. Traditional methods for discovering cancer-related miRNAs mostly require significant marginal differential expression, but some cancer-related miRNAs may be non-differentially or only weakly differentially expressed. Such miRNAs are called as Dark Matters miRNAs (DM-miRNAs) and targeted by Pian et al. (2018) through the Pearson correlation change on miRNA-target interactions (MTIs); but the efficiency of their method heavily relies on restrictive assumptions. In this paper, a novel method was developed to discover DM-miRNAs using Support Vector Machine (SVM) based on not only the miRNA expression data but also the expression of its regulating target. The application of the new method in breast and kidney cancer datasets found respectively 9 and 24 potential DM-miRNAs that cannot be detected by previous methods. 8 and 15 of the newly discovered miRNAs have been found to be associated with breast and kidney cancers respectively in existing literature, respectively. These results indicate that our new method is more effective in discovering cancer-related miRNAs.

    更新日期:2020-01-26
  • The identification of Long non-coding RNA H19 target and its function in Chronic myeloid leukemia (CML)
    Mol. Ther. Nucl. Acids (IF 5.919) Pub Date : 2020-01-25
    Juhua Yang; Zhao Yin; Yumin Li; Yanjun Liu; Guiping Huang; Chunming Gu; Jia Fei

    H19 is a Long non-coding RNA which was lowly expressed in CML. Here,we found that the overexpression of H19 significantly inhibited cell viability and colony formation, and prolong survival in CML cell lines and three xenografted mouse models. The H19 target proteins and miRNAs were identified using a combination of computational prediction and RNA-Pull down, including PCBP1, FUS protein and miR-19a-3p, miR-106b-5p. Targeting PCBP1, FUS protein, miR-19a-3p and miR-106b-5p significantly inhibit the cell growth and colony formation of CML cell lines. Co-overexpression of H19 and PCBP1, FUS, miR-19a-3p and miR-106b-5p decrease the inhibitory effect of H19 in CML. These findings might provide a novel molecular insight into CML.

    更新日期:2020-01-26
  • Long Non-Coding RNA KLF3-AS1 Suppresses Cell Migration and Invasion in Esophageal Squamous Cell Carcinoma by Impairing miR-185-5p-targeted KLF3 Inhibition
    Mol. Ther. Nucl. Acids (IF 5.919) Pub Date : 2020-01-25
    Jun-Qi Liu; Ming Deng; Nan-Nan Xue; Ting-Xuan Li; Yue-Xin Guo; Liang Gao; Di Zhao; Rui-Tai Fan

    Esophageal squamous cell carcinoma (ESCC) is a common cancer occurring to males and females worldwide. Accumulating evidence continues to highlight the crucial roles of long non-coding RNAs (lncRNAs) in the process of tumorigenesis. However, the regulatory mechanism of lncRNAs in ESCC remains unclear. The aim of this study is to elucidate the role of lncRNA KLF3-AS1 in ESCC by regulating miR-185-5p and KLF3. Initially, ESCC cell spheres with stem cell-like properties were prepared by suspension culture, and subsequently characterized by assessing colony formation ability and stem cell markers. LncRNA KLF3-AS1 was found to be poorly expressed in ESCC and could upregulate the expression of KLF3 by binding to miR-185-5p. LncRNA KLF3-AS1 upregulation was observed to inhibit miR-185-5p whereby contributing to decreased expression of SOX2 and Oct4. Furthermore, enhancement of lncRNA KLF3-AS1 resulted in reduced colony formation ability, cell invasion and migration and tumor volume in vivo while promoting cell apoptosis in ESCC through downregulation of miR-185-5p. Collectively, this study indicated that lncRNA KLF3-AS1 inhibited ESCC cell invasion and migration by impairing miR-185-5p-mediated inhibition of KLF3, highlighting a promising novel potential target for ESCC treatment.

    更新日期:2020-01-26
  • Efficacy of Immune Checkpoint Inhibitors in Lung Sarcomatoid Carcinoma
    J. Thorac. Oncol. (IF 12.460) Pub Date : 2020-01-25
    Charlotte Domblides; Karen Leroy; Isabelle Monnet; Julien Mazières; Fabrice Barlesi; Valérie Gounant; Simon Baldacci; Bertrand Mennecier; Anne-Claire Toffart; Clarisse Audigier-Valette; Ludovic Doucet; Etienne Giroux-Leprieur; Florian Guisier; Charles Ricordel; Olivier Molinier; Maurice Perol; Eric Pichon; Gilles Robinet; Marie Wislez

    Background Immune checkpoint inhibitors (ICI) have improved cancer prognosis, but have not been evaluated specifically in sarcomatoid carcinoma (SC), a rare lung cancer subtype with poor prognosis. As such, our study sought to retrospectively assess the ICI efficacy in SC. Methods All consecutive patients with centrally confirmed SC treated in ≥ second-line between 2011 and 2017 were enrolled. PD-L1 tumor expression was assessed using immunohistochemistry (SP263 clone), and the tumor mutational burden (TMB) with the Foundation One panel. TMB was considered high if ≥10 mutations/megabase (MMb). Results Overall, 37 SC patients were evaluated, predominantly men (73%), median age of 63.2 years (36.8-79.7), current or former smokers (94.6%). Immunotherapy (Nivolumab 86.5% of cases) was given in second-line in 54% patients and third-line or beyond in 46%. The ORR was 40.5% and DCR 64.8%, regardless of PD-L1 status. Median OS was 12.7 months [range: 0.3-45.7]. One-third of patients exhibited early progression. The median PD-L1 expression was 70% [0-100]. There was a trend toward higher PD-L1 expression in responsive diseases, with an ORR of 58.8% in PD-L1+ patients and 0% in the single PD-L1- patient (p=0.44). The median TMB was 18 [4-39] MMb, 87.5% of cases displaying a high TMB. There was a trend towards higher TMB in responders versus stable or progressive diseases (p=0.2). Conclusions SC patients exhibited high response rates and prolonged OS under ICI treatment. These data support the prospective investigation of ICI in SC patients in first-line treatment.

    更新日期:2020-01-26
  • Cannabinoids for the Treatment of Chronic Pruritus: A Review
    J. Am. Acad. Dermatol. (IF 7.102) Pub Date : 2020-01-25
    Christina Avila; Susan Massick; Benjamin H. Kaffenberger; Shawn G. Kwatra; Mark Bechtel

    Medical marijuana is becoming widely available to patients in the U.S. and with recreational marijuana now legalized in many states, patient interest is on the rise. The endocannabinoid system plays an important role in skin homeostasis in addition to broader effects on neurogenic responses such as pruritus and nociception, inflammation, and immune reactions. There are numerous studies of in vitro and animal models that provide insight into the possible mechanisms of cannabinoid modulation on pruritus, with the most evidence behind neuronal modulation of both peripheral itch fibers and centrally-acting cannabinoid receptors. In addition, human studies, while limited due to differences in cannabinoids used, disease models, and delivery method, have consistently shown significant reductions in both scratching and symptomatology in chronic pruritus. Clinical studies that have shown reduction in pruritus in several dermatologic (atopic dermatitis, psoriasis, asteatotic eczema, prurigo nodularis, allergic contact dermatitis) and systemic (uremic pruritus, cholestatic pruritus) diseases. These preliminary human studies warrant controlled trials to confirm the benefit of cannabinoids for treatment of pruritus and to standardize treatment regimens and indications. In patients who have refractory chronic pruritus after standard therapies, cannabinoid formulations may be considered as an adjuvant therapy where it is legal.

    更新日期:2020-01-26
  • EFFICACY OF THERAPY FOR EOSINOPHILIC ESOPHAGITIS IN REAL-WORLD PRACTICE
    Clin. Gastroenterol. Hepatol. (IF 7.958) Pub Date : 2020-01-25
    Emilio J. Laserna-Mendieta; Sergio Casabona; Edoardo Savarino; Antonia Perelló; Isabel Pérez-Martínez; Danila Guagnozzi; Jesús Barrio; Antonio Guardiola; Teresa Asensio; Susana de la Riva; Miriam Ruiz-Ponce; Juan Armando Rodríguez-Oballe; Cecilio Santander; Ángel Arias; Alfredo J. Lucendo

    Background & aims Topical steroids, proton pump inhibitors (PPIs), and dietary interventions are recommended first- and second-line therapies for eosinophilic esophagitis (EoE). We investigated differences in their effectiveness in a real-world, clinical practice cohort of patients with EoE. Methods We collected data on the efficacy of different therapies for EoE (ability to induce clinical and histologic remission) from the multicenter EoE CONNECT database—a database of patients with a confirmed diagnosis of EoE in Europe that began in 2016. We obtained data from 589 patients, treated at 11 centers, on sex, age, time of diagnosis, starting date of any therapy, response to therapy, treatment end dates, alternative treatments, and findings from endoscopy. The baseline endoscopy used for diagnosis of EoE; second endoscopy was performed to evaluate response to first-line therapies. After changes in treatment, generally because lack of efficacy, a last endoscopy was performed. The time elapsed between endoscopies depended on the criteria of attending physicians. Clinical remission was defined by a decrease of more than 50% in dysphagia symptom score; improvement in symptoms by less than 50% from baseline was considered as clinical response. Histologic remission was defined as a peak eosinophil count below 5 eosinophils/hpf. A peak eosinophil count between 5 and 14 eosinophils/hpf was considered histologic response. We identified factors associated with therapy selection and effectiveness using χ2 and multinomial logistic regression analyses Results PPIs were the first-line treatment for 76.4% of patients, followed by topical steroids (for 10.5%) and elimination diets (for 7.8%). Topical steroids were most effective in inducing clinical and histologic remission or response (in 67.7% of patients), followed by empiric elimination diets (in 52.0%), and PPIs (in 50.2%). Among the 344 patients who switched to a second-line therapy, dietary interventions were selected for 47.1% of patients, followed by PPIs (for 29.1%) and topical steroids (for 18.6%). Clinical and histologic remission or response was achieved by 80.7% of patients treated with topical steroids, 69.2% of patients given PPIs, and 41.7% of patients on empiric elimination diets. Multivariate analyses found the stricturing phenotype of EoE to be associated with selection of topical steroids over PPIs as the first-line therapy; lack of fibrotic features at initial endoscopy was associated with selection of elimination diets over topical steroids as a second-line therapy. The recruiting center was significantly associated with therapy choice; second-line treatment with topical steroids or PPIs were the only variables associated with clinical and histologic remission. Conclusions In an analysis of data from a large cohort of patients with EoE in Europe, we found topical steroids to be the most effective at inducing clinical and histologic remission, but PPIs to be the most frequently prescribed. Treatment approaches vary with institution and presence of fibrosis or strictures.

    更新日期:2020-01-26
  • Assessing National Trends and Disparities in Ambulatory, Emergency Department, and Inpatient Visits for Inflammatory Bowel Disease in the United States (2005–2016)
    Clin. Gastroenterol. Hepatol. (IF 7.958) Pub Date : 2020-01-25
    Christopher Ma; Matthew Smith; Leonardo Guizzetti; Remo Panaccione; Gilaad G. Kaplan; Kerri L. Novak; Cathy Lu; Reena Khanna; Brian G. Feagan; Siddharth Singh; Vipul Jairath; Ashwin N. Ananthakrishnan

    Background Patients with inflammatory bowel diseases (IBD) require repeated healthcare encounters, although the focus of care differs when patients are seen in ambulatory, emergency department (ED), or inpatient settings. We examined contemporary trends and disparities in IBD-related healthcare visits. Methods We used data from the National Ambulatory Medical Care Survey, Nationwide Emergency Department Sample, and National Inpatient Sample to estimate the total number of annual IBD-related visits from 2005 through 2016. We performed logistic regression analyses to test temporal linear trends. Slope and differences in distributions of patient demographics were compared across time and treatment settings. Results From 2005 through 2016, approximately 2.2 million IBD-related ambulatory visits (95 CI, 1.9–2.5 million IBD-related ambulatory visits) occurred annually on average, increasing by 70.3% from the time period of 2005–2007 through the time period of 2008–2010, and decreasing by 19.8% from the time period of 2011–2013 through the time period of 2014–2016. An average of 115,934 IBD-related ED visits (95% CI, 113,758–118,111 IBD-related ED visits) and 89,111 IBD-related hospital discharges (95% CI, 87,416–90,807 IBD-related hospital discharges) occurred annually. Significant increases in the rate of IBD-related ED visits (3.2 visits/10,000 encounters, P<.0001) and hospital discharges (6.0 discharges/10,000 encounters, P<.0001) were observed from 2005 through 2016. The proportion of patients paying with private insurance decreased from 2005 through 2016, among all care settings. A greater proportion of young patients, patients with Crohn’s disease, non-white patients, and patients with Medicare or Medicaid used hospital-based vs ambulatory services. Conclusions In an analysis of data from 3 large databases, we found that although IBD-related ambulatory visits stabilized-to-decreased from 2005 through 2016, rates of ED use and admission to the hospital have continued to increase with changes in patient demographics, over time and among care settings.

    更新日期:2020-01-26
  • Sensitivity of fecal immunochemical test for colorectal cancer detection differs according to stage and location
    Clin. Gastroenterol. Hepatol. (IF 7.958) Pub Date : 2020-01-25
    Tobias Niedermaier; Kaja Tikk; Anton Gies; Stefanie Bieck; Hermann Brenner

    Background & Aims Fecal immunochemical tests (FITs) are widely used for colorectal cancer (CRC) screening. FITs detect most CRCs. Although detection of CRC at early stages is most relevant for reducing CRC mortality, there is limited evidence for the stage-specific sensitivity of the FIT in CRC detection. We estimated stage- and location-specific sensitivities of a quantitative FIT in a large cohort of patients with CRC. Methods Fecal samples were collected before treatment from 435 patients with newly diagnosed CRC. Sensitivities of a quantitative FIT (FOB Gold, Sentinel Diagnostics; Milano, Italy) for tumors of different T stages and overall TNM stages (according to Union for International Cancer Control) were calculated at the cutoff recommended by the manufacturer (17 μg/g feces) and at alternative cutoffs, ranging from 10 to 40 μg/g feces, overall and stratified by tumor location. Results At the cutoff recommended by the manufacturer, the FIT detected T1 tumors with 52% sensitivity (95% CI, 37%–67%), T2 tumors with 79% sensitivity (95% CI, 68%–88%), T3 tumors with 93% sensitivity (95% CI, 89%–95%), and T4 tumors with 84% sensitivity (95% CI, 72%–92%) (Ptrend <.0001). The FIT detected stage I cancers with 68% sensitivity (95% CI, 57%–78%), stage II cancers with 92% sensitivity (95% CI, 87%–96%), stage III cancers with 82% sensitivity (95% CI, 73%–89%), and stage IV cancers with 89% sensitivity (95% CI, 80%–95%) (Ptrend 0.01). The FIT detected T1 colorectal tumors with sensitivity values that were 22%–52% lower than for tumors of other T stages and stage I CRC with sensitivity values that were 11%–33% lower than for later-stage CRCs, at any of the evaluated cutoff values. The FIT detected T1 and stage I CRCs in the distal colon with sensitivity values of 32% and 52%, respectively. Conclusions Although the FIT identifies patients with CRC with overall high sensitivity, it can miss approximately one-third of stage I CRCs. Studies are needed to increase noninvasive detection of early-stage CRC.

    更新日期:2020-01-26
  • Exercise effects on brain and behavior in healthy mice, Alzheimer’s disease and Parkinson’s disease model - a systematic review and meta-analysis
    Behav. Brain Res. (IF 2.770) Pub Date : 2020-01-25
    Thiago Medeiros da Costa Daniele; Pedro Felipe Carvalhedo de Bruin; Robson Salviano de Matos; Gabriela Sales de Bruin; Cauby Maia Chaves Junior; Veralice Meireles Sales de Bruin

    This systematic review and meta-analysis examines how exercise modifies brain and behavior in healthy mice, dementia (D) and Parkinson disease (PD) models. A search was performed on the Medline and Scopus electronic databases (2008 to 2019). Search terms were “mice”, “brain”, “treadmill”, “exercise”, “physical exercise”. In the total, 430 were found but only 103 were included. Animals (n = 1,172; 96 articles) exercised 4-8 weeks (Range 24 h to 32 weeks), 60 min/day (Range 8 to 120 min per day), and 10/12 m/min (Range 0.2 m/min to 36 m/min). Hippocampus, cerebral cortex, striatum and whole brain were more frequently investigated. Exercise improved learning and memory. Meta-analysis showed that exercise increased: cerebral BDNF in health (n = 150; z = 5.8, CI 3.43-12.05; p < 0.001 I2 = 94.3%), D (n = 124; z = 4.18, CI = 2.22-9.12; p < 0.001; I2 = 93.7%) and PD (n = 16 z = 4.26, CI 5.03-48.73 p < 0.001 I2 = 94.8%). TrkB improved in health (n = 84 z = 5.49, CI 3.8-17.73 p < 0.001, I2 = 0.000) and PD (n = 22; z = 3.1, CI = 2.58-67.3, p < 0.002 I2 = 93.8%). Neurogenesis increased in health (n = 68; z = 7.08, CI 5.65-21.25 p < 0.001; I2 17.58) and D model (n = 116; z = 4.18, CI 2.22-9.12 p < 0.001 I2 93.7%). Exercise augmented amyloid clearance (n = 166; z = 7.51 CI = 4.86-14.85, p < 0.001 I2 = 58.72) and reduced amyloid plaques in D models (n = 49; z = 4.65, CI = 3.94-15.3 p < 0.001 I2 = 0.000). In conclusion, exercise improved brain and behavior, neurogenesis in healthy and dementia models, reduced toxicity and cerebral amyloid. Evidence regarding inflammation, oxidative stress and energy metabolism were scarce. Studies examining acute vs chronic exercise, extreme training and the durability of exercise benefit were rare. Vascular or glucose metabolism changes were seldom reported.

    更新日期:2020-01-26
  • Attention bias towards threat in African American children exposed to early life trauma
    Behav. Brain Res. (IF 2.770) Pub Date : 2020-01-25
    Maya Lakshman; Lauren Murphy; Yara Mekawi; Sierra Carter; Maria Briscione; Bekh Bradley; Erin B. Tone; Seth D. Norrholm; Tanja Jovanovic; Abigail Powers

    Background Attentional bias is linked to a range of mood disorders, including posttraumatic stress disorder (PTSD). The present study examined attention bias patterns in African American children exposed to trauma, in order to better understand potential risk factors for PTSD. Methods 31 children (ages 8–14) completed an eye-tracking task to assess gaze bias patterns while viewing pairs of emotional and neutral faces. Trauma exposure and PTSD symptoms were assessed in a subsample of children (n = 24). Results Repeated measures analysis of variance (ANOVA) results examining attention bias indices and gender showed greater attention bias toward angry faces than happy faces (p < 0.01) and toward emotional faces in males than females (p < 0.05). Correlational analyses showed attention bias toward angry faces was associated with greater levels of child trauma exposure (p < 0.05). Based on linear regression analysis, child trauma exposure accounted for 17 % of variance in attention bias toward angry versus neutral faces independent of gender or posttraumatic stress symptoms (p < 0.05). Conclusions Trauma exposure in children is related to altered attention bias, via enhanced attention towards threatening cues. Results contribute to evidence that males and females may exhibit different attentional patterns. This study highlights the importance of additional research on attention bias patterns and prospective mental health outcomes across gender and through development.

    更新日期:2020-01-26
  • The protective and therapeutic effects of vinpocetine, a PDE1 inhibitor, on oxidative stress and learning and memory impairment induced by an intracerebroventricular (ICV) injection of amyloid beta (Aβ) peptide
    Behav. Brain Res. (IF 2.770) Pub Date : 2020-01-25
    Meysam Shekarian; Alireza Komaki; Siamak Shahidi; Abdolrahman Sarihi; Iraj Salehi; Safoura Raoufi

    Alzheimer’s disease (AD) is a neurodegenerative disease leading to cognitive and memory impairment. This study aimed at investigating the therapeutic and preserving effects of vinpocetine on amyloid beta (Aβ)-induced rat model of AD. Sixty male adult Wistar rats were randomly divided into 6 groups (n = 10 per group) as follows: 1; control, 2; sham, 3; Aβ, 4; pre-treatment (vinpocetine + Aβ): oral gavage administration of vinpocetine at 4 mg/kg for 30 days followed by intracerebroventricular (ICV) injection of Aβ, 5; treatment (Aβ + vinpocetine): Aβ ICV injection followed by vinpocetine administration for 30 days, 6; pre-treatment + treatment (vinpocetine + Aβ + vinpocetine): vinpocetine administration for 30 days before and 30 days after AD induction. Following treatments, the animals’ learning and memory were investigated using passive avoidance learning (PAL) task, Morris water maze (MWM), and novel object recognition (NOR) tests. The results demonstrated that Aβ significantly enhanced escape latency and the distance traveled in the MWM, decreased step-through latency, and increased time spent in the dark compartment in PAL. Vinpocetine ameliorated the Aβ-infused memory deficits in both MWM and PAL tests. Administration of vinpocetine in the Aβ rats increased the discrimination index of the NOR test. It also significantly diminished the nitric oxide and malondialdehyde levels and restored the reduced glutathione (GSH) levels. Vinpocetine can improve memory and learning impairment following Aβ infusion due to its different properties, including antioxidant effects, which indicates that vinpocetine administration can lead to the amelioration of cognitive dysfunction in AD.

    更新日期:2020-01-26
  • Diffusion-limited biosensing of dissolved oxygen by direct electron transfer-type bioelectrocatalysis of multi-copper oxidases immobilized on porous gold microelectrodes
    J. Electroanal. Chem. (IF 3.218) Pub Date : 2020-01-25
    Masahiro Miyata; Yuki Kitazumi; Osamu Shirai; Kunishige Kataoka; Kenji Kano

    Diffusion-controlled amperometric biosensors for dissolved oxygen (O2) were constructed by immobilization of multi-copper oxidases (copper efflux oxidase and bilirubin oxidase) on porous gold microdisk electrodes fabricated by anodization in a glucose solution. The immobilized enzymes rapidly consumed O2 near the electrode at potentials more negative than 0.2 V vs. Ag|AgCl|sat. KCl via direct electron transfer-type bioelectrocatalysis and the reduction current reached the steady state limiting value under static conditions. The fabricated biosensor exhibited a linear response to dissolved O2 concentration and was almost identical to the theoretical sensor, based on nonlinear diffusion of O2 around the microdisk electrode. The biosensor response was fast enough to monitor the catalytic consumption of dissolved O2 by glucose oxidase and exhibited storage stability for more than six days.

    更新日期:2020-01-26
  • Electrodeposition of chromium on single-crystal electrodes from solutions of Cr(II) and Cr(III) salts in ionic liquids
    J. Electroanal. Chem. (IF 3.218) Pub Date : 2020-01-25
    Elena B. Molodkina; Maria R. Ehrenburg; Peter Broekmann; Alexander V. Rudnev

    Herein, we present a study on the initial stages of chromium electrodeposition on platinum and gold single-crystal surfaces from an ionic liquid containing dicyanamide anions. We employed conventional electrochemical techniques in combination with in situ and ex situ scanning probe microscopy (in situ scanning tunneling microscopy (STM), ex situ atomic force microscopy (AFM)) and ex situ X-ray photoemission spectroscopy (XPS). Cr electrodeposition was carried out from Cr(II) and Cr(III) solutions of low (10 mM) and high (250 mM) Cr concentrations. The microscopic and spectroscopic approaches clearly demonstrate the formation of a Cr deposit, although the voltammetric responses are difficult to interpret. The absence of a pronounced Cr dissolution peak in the backward scan of the cyclic voltammograms and a relatively low amount of Cr deposit (as confirmed by AFM) suggest the passivation of Cr and the substrate during deposition, thus hindering both further deposition of Cr and its anodic dissolution.

    更新日期:2020-01-26
  • 更新日期:2020-01-26
  • Structural and electrochemical investigation of lithium ions insertion processes in polyanionic compounds of lithium and transition metals
    J. Electroanal. Chem. (IF 3.218) Pub Date : 2020-01-25
    Aleksandr V. Ivanishchev; Nelly A. Gridina; Kirill S. Rybakov; Irina A. Ivanishcheva; Ambesh Dixit
    更新日期:2020-01-26
  • Investigation of electrocatalytic behaviour of low symmetry cobalt phthalocyanines when clicked to azide grafted carbon electrodes
    J. Electroanal. Chem. (IF 3.218) Pub Date : 2020-01-25
    Lekhetho S. Mpeta; Pinar Sen; Tebello Nyokong

    This work describes the electrochemical properties of low symmetry cobalt phthalocyanines namely, tris-[(4-tert-butylphenoxy)-4-(pent-4-yn-1-yloxy) phthalocyaniato] cobalt (II) (3) and tris-[(4-tert-butylphenoxy)-4-(4-ethybylbenzyl-oxy) phthalocyaniato] cobalt (II) (5). The complexes were characterized by a number of techniques including UV–Vis, mass, and infrared spectra, as well as elemental analysis. The glassy carbon electrodes were first azide functionalized then clicked to low symmetry phthalocyanines. The click reaction was confirmed using X-ray photoelectron spectra. The constructed electrodes showed excellent electrocatalytic activity towards hydrazine oxidation. Oxidation peaks with low potentials of 0.21 V and 0.26 V, for complexes 3 and 5, respectively were obtained. Complex 5 gave a better detection limit of 0.94 μM and electrocatalytic rate constant of 5.6 × 106 M−1 s−1.

    更新日期:2020-01-26
  • A multi-level programming for shale gas-water supply chains accounting for tradeoffs between economic and environmental concerns
    Comput. Chem. Eng. (IF 3.334) Pub Date : 2020-01-25
    Yizhong Chen; Xi Cheng; Jing Li; Li He

    This study develops a multi-level programming model for the planning shale gas-water supply chains. A set of leader-follower-interactive objectives with emphases of water consumption, economic performance, and pollutant discharge are integrated into a sequential decision-making process. Satisfactory degree is introduced to tackle the computationally challenging problem based on an interactive fuzzy approach. Operational decisions regarding water resources allocation, transportation mode selection, and pollutant discharge control would be achieved. Results reveal that the environmentally- or economically-aggressive strategies would be generated when a single goal for optimizing economic benefits or pollutant discharge. The multi-objective decisions are limited by the selected weights. However, the multi-level model would provide more comprehensive schemes due to its sequential consideration of the economic/environmental concerns. Findings from the multi-level model can facilitate (a) balancing the conflicts among different decision makers, (b) timing and siting for shale gas production, and (c) managing water resources for pollutant discharge control.

    更新日期:2020-01-26
  • Regression and independence based variable importance measure
    Comput. Chem. Eng. (IF 3.334) Pub Date : 2020-01-25
    Xinmin Zhang; Takuya Wada; Koichi Fujiwara; Manabu Kano

    Evaluating the importance of input (predictor) variables is of interest in many applications of statistical models. However, nonlinearity and correlation among variables make it difficult to measure variable importance accurately. In this work, a novel variable importance measure, called regression and independence based variable importance (RIVI), is proposed. RIVI is designed by integrating Gaussian process regression (GPR) and Hilbert-Schmidt independence criterion (HSIC) so that it is applicable to nonlinear systems. The results of two numerical examples demonstrate that RIVI is superior to several conventional measures including the Pearson correlation coefficient, PLS-β, PLS-VIP, Lasso, HSIC, and permutation importance with random forest in the variable identification accuracy.

    更新日期:2020-01-26
  • Molecular Mechanisms Regulating Carbohydrate Metabolism During Lolium perenne Regrowth Vary in Response to Nitrogen and Gibberellin Supply
    J. Plant Growth. Regul. (IF 2.179) Pub Date : 2020-01-25
    Qianhe Liu, Susanne Rasmussen, Linda J. Johnson, Hong Xue, Anthony J. Parsons, Chris S. Jones

    Abstract The promoting effects of both high nitrogen (N) and exogenous gibberellin (GA) supply on regrowth of Lolium perenne have been widely reported. The mobilisation of carbohydrate reserves in response to N is a critical mechanism for promoting plant regrowth. However, our knowledge about GA regulation of carbohydrate metabolism remains limited. Here, we analysed the effects of both N and exogenous GA on the molecular mechanisms controlling perennial ryegrass regrowth and investigated the similarities and differences. Our analyses show that both high N and exogenous GA supply lead to a decline in the accumulation of carbohydrate reserves, but the regulatory mechanisms responsible for this decline varied between N and GA supply. The effects of elevated N were mainly through declining fructan biosynthesis which results in improving photosynthate use efficiency to promote plant regrowth, whereas the application of exogenous GA resulted in an increase in the hydrolytic activities of fructan exohydrolase and invertases capable of cleaving reserved carbohydrates to release energy sources for plant regrowth.

    更新日期:2020-01-26
  • Sweet Basil Growth, Physiological and Ultrastructural Modification, and Oxidative Defense System Under Water Deficit and Silicon Forms Treatment
    J. Plant Growth. Regul. (IF 2.179) Pub Date : 2020-01-24
    S. Farouk, M. M. Omar

    Abstract The current investigation aimed to evaluate the role of silicon forms on sweet basil (Ocimum basilicum L.) biomass and essential oil (EO) production, as well as some physiological and ultrastructural modification under different irrigation regimes. Drought significantly decreased plant growth, photosynthetic pigment, ion, relative water content, catalase activity, and EO yield, meanwhile, increased organic and antioxidant solute concentration, EO percentage, peroxidase activity, and oxidative impairment criteria (hydrogen peroxide, lipid peroxidation, and membrane permeability percentage). Concerning EO constituents, linalool and methyl chavicol were the major components that decreased under drought relative to well-watered plants. Exogenous application of silicon forms under well-watered or drought condition may fully or partially compensate to some extent to sweet basil plant development and biochemical attributes (photosynthetic pigment, ion percentage, antioxidant solutes, and organic osmolytes). The maximum EO yield was obtained by 250 mg L−1 sodium metasilicate (Si) under mild drought. Cell organelles exhibited a different degree of malformation and lyse under severe drought; conversely, application of Si forms nullify the abovementioned injuries caused by drought. In conclusion, application of 250 mg L−1 Si improved drought tolerance in sweet basil herb and EO yield by accelerating their antioxidant system, osmoregulation, and maintaining organelles ultrastructure that induced herb growth and EO yield.

    更新日期:2020-01-26
  • From bulk loops to boundary large-N expansion
    J. High Energy Phys. (IF 5.833) Pub Date : 2020-01-24
    Dmitry Ponomarev

    Abstract We study the analytic structure of loop Witten diagrams in Euclidean AdS represented by their conformal partial wave expansions. We show that, as in flat space, amplitude’s singularities are associated with non-trivial cuts of the diagram and factorize into products of the coefficient functions for the subdiagrams resulting from these cuts. We consider an example of a one-loop four-point diagram in detail and then briefly discuss how the procedure can be extended to more general diagrams. Finally, we show that this analysis reproduces simple relations that follow from the large-N considerations on the boundary.

    更新日期:2020-01-26
  • Gravitational corner conditions in holography
    J. High Energy Phys. (IF 5.833) Pub Date : 2020-01-24
    Gary T. Horowitz, Diandian Wang

    Abstract Contrary to popular belief, asymptotically anti-de Sitter solutions of gravitational theories cannot be obtained by taking initial data (satisfying the constraints) on a spacelike surface, and choosing an arbitrary conformal metric on the timelike boundary at infinity. There are an infinite number of corner conditions that also must be satisfied where the initial data surface hits the boundary. These are well known to mathematical relativists, but to make them more widely known we give a simple explanation of why these conditions exist and discuss some of their consequences. An example is given which illustrates their power. Some implications for holography are also mentioned.

    更新日期:2020-01-26
  • The Higgs mechanism — Hasse diagrams for symplectic singularities
    J. High Energy Phys. (IF 5.833) Pub Date : 2020-01-24
    Antoine Bourget, Santiago Cabrera, Julius F. Grimminger, Amihay Hanany, Marcus Sperling, Anton Zajac, Zhenghao Zhong

    Abstract We explore the geometrical structure of Higgs branches of quantum field theories with 8 supercharges in 3, 4, 5 and 6 dimensions. They are symplectic singularities, and as such admit a decomposition (or foliation ) into so-called symplectic leaves, which are related to each other by transverse slices. We identify this foliation with the pattern of partial Higgs mechanism of the theory and, using brane systems and recently introduced notions of magnetic quivers and quiver subtraction, we formalise the rules to obtain the Hasse diagram which encodes the structure of the foliation. While the unbroken gauge symmetry and the number of flat directions are obtainable by classical field theory analysis for Lagrangian theories, our approach allows us to characterise the geometry of the Higgs branch by a Hasse diagram with symplectic leaves and transverse slices, thus refining the analysis and extending it to non-Lagrangian theories. Most of the Hasse diagrams we obtain extend beyond the cases of nilpotent orbit closures known in the mathematics literature. The geometric analysis developed in this paper is applied to Higgs branches of several Lagrangian gauge theories, Argyres-Douglas theories, five dimensional SQCD theories at the conformal fixed point, and six dimensional SCFTs.

    更新日期:2020-01-26
  • 4d N$$ \mathcal{N} $$ = 1 from 6d D-type N$$ \mathcal{N} $$ = (1, 0)
    J. High Energy Phys. (IF 5.833) Pub Date : 2020-01-23
    Jin Chen, Babak Haghighat, Shuwei Liu, Marcus Sperling

    Abstract Compactifications of 6d \( \mathcal{N} \) = (1, 0) SCFTs give rise to new 4d \( \mathcal{N} \) = 1 SCFTs and shed light on interesting dualities between such theories. In this paper we continue exploring this line of research by extending the class of compactified 6d theories to the D- type case. The simplest such 6d theory arises from D5 branes probing D-type singularities. Equivalently, this theory can be obtained from an F-theory compactification using −2- curves intersecting according to a D-type quiver. Our approach is two-fold. We start by compactifying the 6d SCFT on a Riemann surface and compute the central charges of the resulting 4d theory by integrating the 6d anomaly polynomial over the Riemann surface. As a second step, in order to find candidate 4d UV Lagrangians, there is an intermediate 5d theory that serves to construct 4d domain walls. These can be used as building blocks to obtain torus compactifications. In contrast to the A-type case, the vanishing of anomalies in the 4d theory turns out to be very restrictive and constraints the choices of gauge nodes and matter content severely. As a consequence, in this paper one has to resort to non- maximal boundary conditions for the 4d domain walls. However, the comparison to the 6d theory compactified on the Riemann surface becomes less tractable.

    更新日期:2020-01-26
  • Isolated zeros destroy Fermi surface in holographic models with a lattice
    J. High Energy Phys. (IF 5.833) Pub Date : 2020-01-23
    Floris Balm, Alexander Krikun, Aurelio Romero-Bermúdez, Koenraad Schalm, Jan Zaanen

    Abstract We study the fermionic spectral density in a strongly correlated quantum system described by a gravity dual. In the presence of periodically modulated chemical potential, which models the effect of the ionic lattice, we explore the shapes of the corresponding Fermi surfaces, defined by the location of peaks in the spectral density at the Fermi level. We find that at strong lattice potentials sectors of the Fermi surface are unexpectedly destroyed and the Fermi surface becomes an arc-like disconnected manifold. We explain this phenomenon in terms of a collision of the Fermi surface pole with zeros of the fermionic Green’s function, which are explicitly computable in the holographic dual.

    更新日期:2020-01-26
  • Generalised power series expansions for the elliptic planar families of Higgs + jet production at two loops
    J. High Energy Phys. (IF 5.833) Pub Date : 2020-01-23
    F. Moriello

    Abstract We obtain generalised power series expansions for a family of planar two-loop master integrals relevant for the QCD corrections to Higgs + jet production, with phys- ical heavy-quark mass. This is achieved by defining differential equations along contours connecting two fixed points, and by solving them in terms of one-dimensional generalised power series. The procedure is efficient, and can be repeated in order to reach any point of the kinematic regions. The analytic continuation of the series is straightforward, and we present new results below and above the physical thresholds. The method we use allows to compute the integrals in all kinematic regions with high precision. For example, per- forming a series expansion on a typical contour above the heavy-quark threshold takes on average O(1 second) per integral with worst relative error of O(10−32), on a single CPU core. After the series is found, the numerical evaluation of the integrals in any point of the contour is virtually instant. Our approach is general, and can be applied to Feynman integrals provided that a set of differential equations is available.

    更新日期:2020-01-26
  • Off-shell unimodular N = 1 , d = 4 supergravity
    J. High Energy Phys. (IF 5.833) Pub Date : 2020-01-22
    Jesus Anero, Carmelo P. Martin, Raquel Santos-Garcia

    Abstract We formulate a unimodular N = 1, d = 4 supergravity theory off shell. We see that the infinitesimal Grassmann parameters defining the unimodular supergravity trans- formations are constrained and show that the conmutator of two infinitesinal unimodular supergravity transformations closes on transverse diffeomorphisms, Lorentz transforma- tions and unimodular supergravity transformations. Along the way, we also show that the linearized theory is a supersymmetric theory of gravitons and gravitinos. We see that de Sitter and anti-de Sitter spacetimes are non-supersymmetric vacua of our unimodular supergravity theory.

    更新日期:2020-01-26
  • Modular A 4 invariance and leptogenesis
    J. High Energy Phys. (IF 5.833) Pub Date : 2020-01-22
    Takehiko Asaka, Yongtae Heo, Takuya H. Tatsuishi, Takahiro Yoshida

    Abstract We consider a model with three right-handed neutrinos in which Yukawa coupling constants and Majorana masses are obtained by requiring the modular A4 symmetry. It has been shown that the model can explain mass hierarchies and mixing patterns of charged leptons and neutrinos with the seesaw mechanism. In this article we investigate the leptogenesis by decays of right-handed neutrinos in this model. It is shown that masses of right-handed neutrinos are about 1013 GeV in order to account for the observed baryon asymmetry of the universe. Furthermore, the positive sign of the baryon asymmetry is obtained only for the limited ranges of mixing angles and CP violation phases of active neutrinos, which can be tested by future neutrino experiments.

    更新日期:2020-01-26
  • Optimization of extraction methods for the analysis of PFOA and PFOS in the salty matrices during the wastewater treatment
    Microchem. J. (IF 3.206) Pub Date : 2020-01-25
    Yang Liu; Jia Bao; Xiao-Min Hu; Gui-Lin Lu; Wen-Jing Yu; Zhen-Hao Meng

    Water bodies of numerous countries and regions in the world have been contaminated to various extents with the widespread production and usage of perfluoroalkyl substances (PFASs). Both domestic and industrial wastewaters become one of the important sources for the PFAS contaminations in natural water bodies, due to the incomplete treatment. Usually, the artificial wastewaters are complex and have high concentrations of inorganic salts, which could result in the matrix effects during the process of analysis for PFASs, contributing to quantify the target compounds inaccurately. In order to monitor the concentrations of PFAS contaminants precisely, suitable extraction methods were compared focusing on the matrix effects and characters of green analytical chemistry during the detection of perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) existing with several common inorganic salts in wastewaters. The results showed that the analytical values of PFOA and PFOS were 2.8-3.6 times and 3.0-5.2 times higher than the theoretical values, respectively. The liquid-liquid extraction (LLE) and solid phase extraction (SPE) methods were used to reduce the matrix effects originated from inorganic salts, consequently the SPE method was confirmed as the optimal extraction method, based upon both the recoveries and green procedures. Combined with the application of the best parameters in real industrial wastewaters, indicating the present study would provide an accurate and green quantitative analysis of PFASs in salty wastewaters.

    更新日期:2020-01-26
  • BPS states, conserved charges and centres of symmetric group algebras
    J. High Energy Phys. (IF 5.833) Pub Date : 2020-01-22
    Garreth Kemp, Sanjaye Ramgoolam

    Abstract In \( \mathcal{N} \) = 4 SYM with U(N) gauge symmetry, the multiplicity of half-BPS states with fixed dimension can be labelled by Young diagrams and can be distinguished using conserved charges corresponding to Casimirs of U(N). The information theoretic study of LLM geometries and superstars in the dual AdS5× S5 background has raised a number of questions about the distinguishability of Young diagrams when a finite set of Casimirs are known. Using Schur-Weyl duality relations between unitary groups and symmetric groups, these questions translate into structural questions about the centres of symmetric group algebras. We obtain algebraic and computational results about these structural properties and related Shannon entropies, and generate associated number sequences. A characterization of Young diagrams in terms of content distribution functions relates these number sequences to diophantine equations. These content distribution functions can be visualized as connected, segmented, open strings in content space.

    更新日期:2020-01-26
  • UPLC Separation of forced degradation and process related impurities of Velpatasvir and structure elucidation by online LC-Quadrupole-Time of flight-Tandem mass Spectrometry
    Microchem. J. (IF 3.206) Pub Date : 2020-01-25
    Debasish Swain; Amrej Singh Yadav; Chandrasekhar Sasapu; Venkatakrishna Akula; Gananadhamu Samanthula

    Drug substances undergo degradation during manufacturing process and storage of finished pharmaceutical products which often results in the generation of degradation products. When process-related substances and degradation products are present as impurities, the therapeutic effect of the drug may alter or cause adverse effects. To address these issues, a mass compatible selective reverse phase UPLC method was developed and validated for separation of Velpatasvir (VPR) and some of its impurities. VPR was subjected to hydrolytic, oxidative, photolytic and thermal stress conditions as prescribed by ICH. Four process-related substances and eight stress degradation products (DPs) were separated on an Acquity Phenyl-Hexyl (100 × 2.1 mm x 1.8 µm) column using 0.1% formic acid and methanol as eluent with gradient program. The same method was applied to LC coupled tandem mass spectrometer for separation and structure elucidation of impurities. Out of eight degradation impurities; two degradation products (V1 and V2) were obtained in acid hydrolysis, another two DPs (V3 and V4) formed in alkaline hydrolysis. Four DPs (V5, V6, V7 and V8) were obtained in oxidative stress. V7 and V8 were obtained as major degradation products and their chemical structures were further confirmed by NMR experiments. The performance of this method was validated for parameters by following ICH Q2 (R1) guideline. This method can be utilized in the identification of impurities in bulk drug manufacturing and dosage form design studies.

    更新日期:2020-01-26
  • Transplanckian censorship and the local swampland distance conjecture
    J. High Energy Phys. (IF 5.833) Pub Date : 2020-01-21
    Patrick Draper, Szilard Farkas

    Abstract The swampland distance conjecture (SDC) addresses the ability of effective field theory to describe distant points in moduli space. It is natural to ask whether there is a local version of the SDC: is it possible to construct local excitations in an EFT that sample extreme regions of moduli space? In many cases such excitations exhibit horizons or instabilities, suggesting that there are bounds on the size and structure of field excitations that can be achieved in EFT. Static bubbles in ordinary Kaluza-Klein theory provide a simple class of examples: the KK radius goes to zero on a smooth surface, locally probing an in- finite distance point, and the bubbles are classically unstable against radial perturbations. However, it is also possible to stabilize KK bubbles at the classical level by adding flux. We study the impact of imposing the Weak Gravity Conjecture (WGC) on these solutions, finding that a rapid pair production instability arises in the presence of charged matter with q/m ≳ 1. We also analyze 4d electrically charged dilatonic black holes. Small curvature at the horizon imposes a bound log (MBH) ,≳ |∆𝜙|, independent of the WGC, and the bound can be strengthened if the particle satisfying the WGC is sufficiently light. We conjecture that quantum gravity in asymptotically flat space requires a general bound on large localized moduli space excursions of the form |∆𝜙| ≲ | log(RΛ)|, where R is the size of the minimal region enclosing the excitation and Λ−1 is the short-distance cutoff on local EFT. The bound is qualitatively saturated by the dilatonic black holes and Kaluza-Klein monopoles.

    更新日期:2020-01-26
  • HPLC-DAD method for the quantitative determination of short-chain fatty acids in meconium samples
    Microchem. J. (IF 3.206) Pub Date : 2020-01-25
    Justyna Dobrowolska-Iwanek; Ryszard Lauterbach; Hubert Huras; Paweł Paśko; Ewelina Prochownik; Michał Woźniakiewicz; Sabina Chrząszcz; Paweł Zagrodzki

    The purpose of this study was to develop and validate a high-performance liquid chromatography with a diode-array detector (HPLC-DAD) method for the determination of short-chain fatty acids (SCFAs) such as: acetic, propionic, butyric, valeric and isovaleric acids in meconium. Additionally, the proposed analytical procedure was used to determine SCFAs in meconium obtained from 17 neonates. All determined organic acids in meconium samples were separated with good resolution. The HPLC system was characterized by high precision (the coefficient of variance ≤ 2.5%), high determination coefficients of calibration curves (R2>0.997) and low limits of detection (LOD) and quantification (LOQ). For all investigated organic acids, LOD ranged from 0.01 to 0.80 mmol/ kg and LOQ values ranged between 0.04 and 2.64 mmol/ kg. Recovery of the HPLC assay for individual analytes comprised the range of 90±2 - 106±2%. Concentrations of acids in meconium collected from healthy children varied in wide ranges (CV within the range 0.79-2.47%) and no regularity was found in the molar ratios of the individual acids. The validation parameters obtained in this study, made the HPLC-DAD method reliable and useful tool for the determination of short-chain fatty acids in meconium samples.

    更新日期:2020-01-26
  • A new naphthopyran-based chemodosimeter with aggregation-induced emission: selective dual-channel detection of cyanide ion in aqueous medium and test strips
    Microchem. J. (IF 3.206) Pub Date : 2020-01-25
    Zhen Ming Dong; Hong Ren; Jia Na Wang; Yu Wang

    A novel green emissive AIE active probe, a naphthopyran-malononitrile conjugate (NPM), was utilized for selective dual channel (colorimetric and fluorimetric) sensing of CN− ions in DMSO-water (2/3, v/v, pH=7.4) solution. The nucleophilic addition of CN− ion on the dicyano-vinyl group breaks the π-electron conjugation, thereby restricting intra-molecular charge transfer(ICT) process in the probe NPM and leading to a visual color change and observable spectral changes. NPM shows good selectivity for CN− ions with the LOD of 4.27 × 10−7 M, which renders it a candidate probe for cyanide detection in aqueous environments. For the practical applicability, NPM-coated paper strips were prepared for convenient, on-site detection of cyanide in aqueous medium.

    更新日期:2020-01-26
  • The dynamical diquark model: fine structure and isospin
    J. High Energy Phys. (IF 5.833) Pub Date : 2020-01-21
    Jesse F. Giron, Richard F. Lebed, Curtis T. Peterson

    Abstract We incorporate fine-structure corrections into the dynamical diquark model of multiquark exotic hadrons. These improvements include effects due to finite diquark size, spin-spin couplings within the diquarks, and most significantly, isospin-dependent couplings in the form of pionlike exchanges assumed to occur between the light quarks within the diquarks. Using a simplified two-parameter interaction Hamiltonian, we obtain fits in which the isoscalar JPC = 1++ state — identified as the X (3872) — appears naturally as the lightest exotic (including all states that are predicted by the model but have not yet been observed), while the closed-charm decays of Zc(3900) and Zc(4020) prefer J/𝜓 and hc modes, respectively, in accord with experiment. We explore implications of this model for the excited tetraquark multiplets and the pentaquarks.

    更新日期:2020-01-26
  • Fused-silica capillary internally modified with nanostructured octadecyl silica for dynamic in-tube solid-phase microextraction of polycyclic aromatic hydrocarbons from aqueous media
    Microchem. J. (IF 3.206) Pub Date : 2020-01-25
    Fardin Harati; Alireza Ghiasvand; Kolsoum Dalvand; Paul R. Haddad

    The internal surface of a fused-silica capillary was made much more porous, more adsorptive and resistant to chemical and mechanical stresses by chemical coating using nanostructured octadecyl silica particles. The modification process was conducted using a simple and green nucleosynthesis procedure. The internally modified capillary was used as an in-tube solid-phase microextraction (IT-SPME) device for the extraction and preconcentration of ultratrace levels of polycyclic aromatic hydrocarbons (PAHs) in aqueous samples, followed by determination using gas chromatography-flame ionization detection (GC-FID) system. Morphology and structure of the sorbent was characterized by FT-IR, SEM and energy dispersive X-ray techniques. The effects of a range of experimental variables on the efficiency of the IT-SPME-GC-FID method were evaluated and optimized. Under the optimal conditions, good linearity (R2>0.99) was obtained for the calibration graphs over the range of 1-4000 ng mL−1. Detection limits were 0.22-0.47 ng mL−1 and relative standard deviations were obtained in the range 4.4-10.3%. Recoveries of the spiked samples were found to be 78.7-103.5%. The proposed IT-SPME-GC-FID strategy was applied successfully for the analysis of PAHs in real water samples. The results demonstrated good analytical performances, compared with those reported elsewhere for the sampling and quantification of PAHs in aqueous media.

    更新日期:2020-01-26
  • Mapping pigments and binders in 15th century Gothic works of art using a combination of visible and near infrared hyperspectral imaging
    Microchem. J. (IF 3.206) Pub Date : 2020-01-25
    L. de Viguerie; N. Oriols Pladevall; H. Lotz; V. Freni; N. Fauquet; M. Mestre; P. Walter; M. Verdaguer

    Visible and near infrared hyperspectral imaging have allowed unprecedented analyses of two major works of art of the National Museum of Catalan Art (MNAC), 15th century Gothic altarpieces: (1) Madonna of the ‘Consellers’ (Lluís Dalmau, 1443-1445) [1], an impressive piece of Catalan painting, inspired by J. van Eyck and (2) Princess Eudoxia exorcised in front of St. Stephen's tomb (Vergós Group, 1495-1500) part of the altarpiece of Sant Esteve de Granollers. Visible and near infrared (VNIR) hyperspectral imaging was used to highlight the artist's handling of materials in achieving light and shadow effects in the red draperies. The refinement in the modelling could be observed thanks to the distribution images of the red pigments. Short-wavelength infrared (SWIR) hyperspectral imaging revealed blackened azurite on visually altered areas of the two paintings. It is possible to map the presence of azurite below the altered layer and obtain a better understanding of the earlier appearance of the paintings. It was moreover possible to identify and map the binders used in both works of art: the use of oil in Dalmau's painting, as the earliest Catalan oil painting, is confirmed here whereas in the Vergós's painting both egg and oil may have been used in separate areas.

    更新日期:2020-01-26
  • Preparation of nickel-aluminum hydrotalcite nanosheet-coated carbon nanofibers and their application in the detection of salidroside
    Microchem. J. (IF 3.206) Pub Date : 2020-01-25
    Xiaojing SI; Chaolin WANG; Li LI; Daixin YE; Youli WEI; Yaping DING

    A facile and highly sensitive electrochemical sensor for salidroside was fabricated based on multilayer ultrathin films (UTFs) containing Ni–Al layered double hydroxide (LDH) and carbon fibers that obtained by electrospinning technology. The X-ray diffraction )XRD(, scanning electron microscope )SEM( and transmission electron microscopy (TEM) images show that the film surface is synthesized successfully. In addition, we constructed the electrochemical sensor using the composite nanomaterials we prepared to achieve detection of salidroside and this sensor showed a good linear range (0.2-120 μM) and a low detection limit (0.067 μM). It has also been successfully applied to the detection of actual samples, compared with HPLC method, satisfactory recovery rates have also been obtained.

    更新日期:2020-01-26
  • Light entrainment of retinal biorhythms: cryptochrome 2 as candidate photoreceptor in mammals
    Cell. Mol. Life Sci. (IF 7.014) Pub Date : 2020-01-25
    Jacques Vanderstraeten, Philippe Gailly, E. Pascal Malkemper

    Abstract The mechanisms that synchronize the biorhythms of the mammalian retina with the light/dark cycle are independent of those synchronizing the rhythms in the central pacemaker, the suprachiasmatic nucleus. The identity of the photoreceptor(s) responsible for the light entrainment of the retina of mammals is still a matter of debate, and recent studies have reported contradictory results in this respect. Here, we suggest that cryptochromes (CRY), in particular CRY 2, are involved in that light entrainment. CRY are highly conserved proteins that are a key component of the cellular circadian clock machinery. In plants and insects, they are responsible for the light entrainment of these biorhythms, mediated by the light response of their flavin cofactor (FAD). In mammals, however, no light-dependent role is currently assumed for CRY in light-exposed tissues, including the retina. It has been reported that FAD influences the function of mammalian CRY 2 and that human CRY 2 responds to light in Drosophila, suggesting that mammalian CRY 2 keeps the ability to respond to light. Here, we hypothesize that CRY 2 plays a role in the light entrainment of retinal biorhythms, at least in diurnal mammals. Indeed, published data shows that the light intensity dependence and the wavelength sensitivity commonly reported for that light entrainment fits the light sensitivity and absorption spectrum of light-responsive CRY. We propose experiments to test our hypothesis and to further explore the still-pending question of the function of CRY 2 in the mammalian retina.

    更新日期:2020-01-26
  • Metabolite profiling reveals a complex response of plants to application of plant growth-promoting endophytic bacteria
    Microbiol. Res. (IF 3.701) Pub Date : 2020-01-25
    Ahmad Mahmood; Ryota Kataoka

    Endophytic bacteria have been explored for their role in plant growth promotion, however, not much has been explored in cucumber. The metabolomic response of plants to application of such microbes also remains largely unknown. Thus, we investigated the application of endophytic bacteria to cucumber to infer their role in plant growth promotion and document metabolome response. The lowest healthy leaf-stalks were sampled from four differently sourced cucumber plants, and endophytic bacteria were isolated after surface disinfection. Initial plant growth-promoting (PGP) screening was performed to identify PGP strains out of numerous isolates, and five strains (Strains 4=Curtobacterium spp., 72=Brevibacillus spp., 167=Paenibacillus spp., 193=Bacillus spp., and 227=Microbacterium spp.) were selected based on their contribution to root growth compared with the control. The selected strains were further evaluated in pot experiments, axenic PGP trait assays, and metabolomic analysis. Results revealed that the selected isolates possessed different qualitative characteristics among indole acetic acid, siderophore production, phosphate solubilization, and 1-aminocyclopropane-1-carboxylate (ACC)-deaminase and nifH genes, and all isolates significantly enhanced plant growth in both pot experiments compared with the uninoculated control and fertilizer control. Metabolomic profiling revealed that both strains affected the plant metabolomes compared with the uninoculated control. Around 50% of the metabolites explored had higher concentrations in either or both bacteria-applied plants compared with the uninoculated control. Differences were observed in both strains’ regulation of metabolites, although both enhanced root growth near equally. Overall, endophytic bacteria significantly enhanced plant growth and tended to produce or induce release of certain metabolites within the plant endosphere.

    更新日期:2020-01-26
  • Induction of drought tolerance in tomato upon the application of ACC deaminase producing plant growth promoting rhizobacterium Bacillus subtilis Rhizo SF 48
    Microbiol. Res. (IF 3.701) Pub Date : 2020-01-25
    H.G. Gowtham; S. Brijesh Singh; M. Murali; N. Shilpa; Melvin Prasad; Mohammed Aiyaz; K.N. Amruthesh; S.R. Niranjana

    A total of ten 1-aminocyclopropane-1-carboxylate (ACC) deaminase producing PGPR isolates were selected and evaluated for the induction of drought stress tolerance in tomato. Among the selected PGPR, maximum seed (laboratory) and plant growth promotion (greenhouse) was observed in tomato seeds bacterized with Bacillus subtilis Rhizo SF 48. The genomic study confirmed the presence of ACC deaminase gene in Rhizo SF 48 and the obtained sequence was deposited to the NCBI database with the Accession No. MK652706. The tomato plants grown upon treatment with Rhizo SF 48 significantly enhanced plant growth even after exposing to different levels of drought stress as compared to stress induced control plants. About 7.5% and 38% increase in RWC were observed in Rhizo SF 48 treated tomato plants grown under well-watered and stress conditions (S4) compared to their control plants, respectively. An increase of 0.76, 0.23 and 0.78 fold in proline, SOD and APX activity and a decrease of 0.3 fold in MDA and H2O2 contents were observed in Rhizo SF 48 treated plants compared to control plants grown under S4 conditions. The histo-chemical studies showed lower accumulations of H2O2 and superoxide anion in the leaves of Rhizo SF 48 treated plants under drought stress, which was in confirmation with the quantification results of H2O2 and SOD. The qRT-PCR studies on drought (Le25) and ethylene responsive factor (SlERF84) marker genes showed that a significant decrease of 0.75 and 0.81 folds, respectively in Le25 and SlERF84 accumulation was observed in Rhizo SF 48 treated plants compared to untreated plants grown under S4 conditions. From the results, it can be attributed that ACC deaminase producing Rhizo SF 48 was able to protect tomato plants against oxidative damage caused due to drought stress and enhanced plant growth promotion. It can be concluded that ACC deaminase producing Rhizo SF 48 can serve as a useful bio-inoculant for sustainable tomato production in arid and semi-arid regions with water deficit.

    更新日期:2020-01-26
  • Shotgun Proteomic Analysis of ESBL-Producing and Non-ESBL-Producing Klebsiella Pneumoniae Clinical Isolates
    Microbiol. Res. (IF 3.701) Pub Date : 2020-01-25
    Shymaa Enany; Samira Zakeer; Ahmed A. Sayed

    Klebsiella pneumoniae is a pathogenic bacterium that is responsible for a wide range of infections in humans. An increased rate of infections caused by multi-drug-resistant K. pneumoniae has been noted in the last two decades. The association between antimicrobial resistance and virulence is an important topic of study. Genomic tools have been used widely for the detection of virulence. In our study, we used proteomic analysis with mass spectrometry and bioinformatics tools to explore the virulence factors of both ESBL-producing and non-ESBL-producing K. pneumoniae and to determine the association between virulence and antimicrobial resistance in these clinical isolates. We have revealed different proteomic profiles and different pathways between the ESBL- and non-ESBL-producing groups. Many proteins involved in stress responses have been reported in the shared proteome between ESBL-and non-ESBL producers, such as ElaB protein, Lon protease, and universal stress proteins G and A. The virulence and pathogenicity of ESBL-producing bacteria were stronger than those of the non-ESBL-producing bacteria. Several unique virulence determinants were identified in ESBL-producing K. pneumoniae, such as proteins with lyase, catalase, isochorismatase, and oxidoreductase activity.

    更新日期:2020-01-26
  • Deep Intact Proteoform Characterization in Human Cell Lysate Using High-pH and Low-pH Reversed-Phase Liquid Chromatography
    J. Am. Soc. Mass Spectrom. (IF 3.202) Pub Date : 2019-11-21
    Dahang Yu, Zhe Wang, Kellye A. Cupp-Sutton, Xiaowen Liu, Si Wu

    Abstract Post-translational modifications (PTMs) play critical roles in biological processes and have significant effects on the structures and dynamics of proteins. Top-down proteomics methods were developed for and applied to the study of intact proteins and their PTMs in human samples. However, the large dynamic range and complexity of human samples makes the study of human proteins challenging. To address these challenges, we developed a 2D pH RP/RPLC-MS/MS technique that fuses high-resolution separation and intact protein characterization to study the human proteins in HeLa cell lysate. Our results provide a deep coverage of soluble proteins in human cancer cells. Compared to 225 proteoforms from 124 proteins identified when 1D separation was used, 2778 proteoforms from 628 proteins were detected and characterized using our 2D separation method. Many proteoforms with critically functional PTMs including phosphorylation were characterized. Additionally, we present the first detection of intact human GcvH proteoforms with rare modifications such as octanoylation and lipoylation. Overall, the increase in the number of proteoforms identified using 2DLC separation is largely due to the reduction in sample complexity through improved separation resolution, which enables the detection of low-abundance PTM-modified proteoforms. We demonstrate here that 2D pH RP/RPLC is an effective technique to analyze complex protein samples using top-down proteomics.

    更新日期:2020-01-26
  • An allelic based phenological model to predict phasic development of wheat (Triticum aestivum L.)
    Field Crops Res. (IF 3.868) Pub Date : 2020-01-25
    Brendan Christy; Penny Riffkin; Richard Richards; Debra Partington; Tina Botwright Acuña; Angela Merry; Heping Zhang; Ben Trevaskis; Garry O’Leary

    We developed a photoperiod-corrected thermal model that can predict wheat phenology based solely on the combination of photoperiod (Ppd) and vernalisation (Vrn) alleles to identify the phenological suitability of germplasm across the cropping region in southern Australia. More than 200 wheat genotypes that vary in combinations of Ppd and Vrn alleles were grown at 17 locations spanning 11° Latitude, thus providing a wide range in temperature and daylength gradients. The phenological sensitivities of a genotype to varying basic temperature, photoperiod and vernalisation requirement was adjusted via optimisation to minimise the least square difference between the measured and predicted dates of both terminal spike (TS) and flowering (AN). The model predicted dates of TS and AN to within 5 days of the field values. Information was used to identify the alleles required to achieve a wheat ideotype defined in a previous study. The optimum allelic combinations required to target the optimum flowering period for different locations when sown on different dates were also identified. The use of allelic based phenological models has the potential to reduce the costs to breeding programs and accelerate the release of better adapted germplasm to new and changing environments.

    更新日期:2020-01-26
  • Quantitation of Single and Combinatorial Histone Modifications by Integrated Chromatography of Bottom-up Peptides and Middle-down Polypeptide Tails
    J. Am. Soc. Mass Spectrom. (IF 3.202) Pub Date : 2019-09-11
    Kevin A. Janssen, Mariel Coradin, Congcong Lu, Simone Sidoli, Benjamin A. Garcia

    Abstract The analysis of histone post-translational modifications (PTMs) by mass spectrometry (MS) has been critical to the advancement of the field of epigenetics. The most sensitive and accurate workflow is similar to the canonical proteomics analysis workflow (bottom-up MS), where histones are digested into short peptides (4-20 aa) and quantitated in extracted ion chromatograms. However, this limits the ability to detect even very common co-occurrences of modifications on histone proteins, preventing biological interpretation of PTM crosstalk. By digesting with GluC rather than trypsin, it is possible to produce long polypeptides corresponding to intact histone N-terminal tails (50-60 aa), where most modifications reside. This middle-down MS approach is used to study distant PTM co-existence. However, the most sensitive middle-down workflow uses weak cation exchange-hydrophilic interaction chromatography (WCX-HILIC), which is less robust than conventional reversed-phase chromatography. Additionally, since the buffer systems for middle-down and bottom-up proteomics differ substantially, it is cumbersome to toggle back and forth between both experimental setups on the same LC system. Here, we present a new workflow using porous graphitic carbon (PGC) as a stationary phase for histone analysis where bottom-up and middle-down sized histone peptides can be analyzed simultaneously using the same reversed-phase buffer setup. By using this protocol for middle-down sized peptides, we identified 406 uniquely modified intact histone tails and achieved a correlation of 0.85 between PGC and WCX-HILIC LC methods. Together, our method facilitates the analysis of single and combinatorial histone PTMs with much simpler applicability for conventional proteomics labs than the state-of-the-art middle-down MS.

    更新日期:2020-01-26
  • Comprehensive Characterization of the Recombinant Catalytic Subunit of cAMP-Dependent Protein Kinase by Top-Down Mass Spectrometry
    J. Am. Soc. Mass Spectrom. (IF 3.202) Pub Date : 2019-12-02
    Zhijie Wu, Yutong Jin, Bifan Chen, Morgan K. Gugger, Chance L. Wilkinson-Johnson, Timothy N. Tiambeng, Song Jin, Ying Ge

    Abstract Reversible phosphorylation plays critical roles in cell growth, division, and signal transduction. Kinases which catalyze the transfer of γ-phosphate groups of nucleotide triphosphates to their substrates are central to the regulation of protein phosphorylation and are therefore important therapeutic targets. Top-down mass spectrometry (MS) presents unique opportunities to study protein kinases owing to its capabilities in comprehensive characterization of proteoforms that arise from alternative splicing, sequence variations, and post-translational modifications. Here, for the first time, we developed a top-down MS method to characterize the catalytic subunit (C-subunit) of an important kinase, cAMP-dependent protein kinase (PKA). The recombinant PKA C-subunit was expressed in Escherichia coli and successfully purified via his-tag affinity purification. By intact mass analysis with high resolution and high accuracy, four different proteoforms of the affinity-purified PKA C-subunit were detected, and the most abundant proteoform was found containing seven phosphorylations with the removal of N-terminal methionine. Subsequently, the seven phosphorylation sites of the most abundant PKA C-subunit proteoform were characterized simultaneously using tandem MS methods. Four sites were unambiguously identified as Ser10, Ser11, Ser18, and Ser30, and the remaining phosphorylation sites were localized to Ser2/Ser3, Ser358/Thr368, and Thr[215-224]Tyr in the PKA C-subunit sequence with a 20mer 6xHis-tag added at the N-terminus. Interestingly, four of these seven phosphorylation sites were located at the 6xHis-tag. Furthermore, we have performed dephosphorylation reaction by Lambda protein phosphatase and showed that all phosphorylations of the recombinant PKA C-subunit phosphoproteoforms were removed by this phosphatase.

    更新日期:2020-01-26
  • Discovery of Missing Methylation Sites on Endogenous Peptides of Human Cell Lines
    J. Am. Soc. Mass Spectrom. (IF 3.202) Pub Date : 2019-08-19
    Xin Yan, Lingjun Li, Chenxi Jia

    Abstract Methylation of proteins has considerable impacts on physiological processes including signal transduction, DNA damage repair, transcriptional regulation, gene activation, and inhibition of gene expression. However, the traditional proteomics-based approach suffers from limited identification rates of these critical methylation sites on endogenous peptides. In this work, a peptidomics-based workflow was established to discover and characterize the global methylome of endogenous peptides in human cells. The reliability of our strategy was validated by methyl-SILAC labeling, resulting in 83% true-positive identifications in the HeLa cell line. We applied this approach to seven human cell lines, and 700 methylated forms on 646 putative methylation sites were identified in total, with over 61% of the methylation sites being newly identified. This study provides a complementary strategy for a traditional proteomics-based approach that enables identification of missing methylation sites and creates a first methylome draft of endogenous peptides of human cell lines, offering a valuable resource for in-depth studies of biological functions of methylated endogenous peptides.

    更新日期:2020-01-26
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