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  • Symmetry protected topological Luttinger liquids and the phase transition between them
    Sci. Bull. (IF 4) Pub Date : 2018-05-17
    Hong-Chen Jiang, Zi-Xiang Li, Alexander Seidel, Dung-Hai Lee
    更新日期:2018-05-17
  • High precision nuclear mass predictions towards a hundred kilo-electron-volt accuracy
    Sci. Bull. (IF 4) Pub Date : 2018-05-17
    Zhongming Niu, Haozhao Liang, Baohua Sun, Yifei Niu, Jianyou Guo, Jie Meng
    更新日期:2018-05-17
  • Long-term surface water changes and driving cause in Xiong’an, China: from dense Landsat time series images and synthetic analysis
    Sci. Bull. (IF 4) Pub Date : 2018-05-10
    Chunqiao Song, Linghong Ke, Hang Pan, Shengan Zhan, Kai Liu, Ronghua Ma
    更新日期:2018-05-10
  • Structural insights into the CRISPR-Cas-associated ribonuclease activity of Staphylococcus epidermidis Csm3 and Csm6
    Sci. Bull. (IF 4) Pub Date : 2018-05-03
    Yanqun Zhao, Jinjing Wang, Qiu Sun, Chao Dou, Yijun Gu, Chunlai Nie, Xiaofeng Zhu, Yuquan Wei, Wei Cheng

    The Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)-CRISPR-associated (Cas) system is an adaptive immune system in bacteria and archaea that resists exogenous invasion through nucleicacid-mediated cleavage. In the type III-A system, the Csm complex contains five effectors and a CRISPR RNA, which edits both single stranded RNA and double stranded DNA. It has recently been demonstrated that cyclic oligoadenylates (cOAs), which are synthesized by the Csm complex, act as second messengers that bind and activate Csm6. Here, we report the crystal structures of Staphylococcus epidermidis Csm3 (SeCsm3) and an N-terminally truncated Csm6 (SeCsm6ΔN) at 2.26 and 2.0Å, respectively. The structure of SeCsm3 highly resembled previously reported Csm3 structures from other species; however, it provided novel observations allowing further enzyme characterization. The homodimeric SeCsm6ΔN folds into a compact structure. The dimerization of the HEPN domain leads to the formation of the ribonuclease active site, which is consistent with the reported Csm6 structures. Altogether, our studies provide a structural view of the ribonuclease activity mediated by Csm3 and Csm6 of the type III-A CRISPR-Cas system.

    更新日期:2018-05-03
  • Widening and weakening of the Hadley circulation under global warming
    Sci. Bull. (IF 4) Pub Date : 2018-04-28
    Yongyun Hu, Han Huang, Chen Zhou

    The Hadley circulation is one of the most important atmospheric circulations. Widening of the Hadley circulation has drawn extensive studies in the past decade. The key concern is that widening of the Hadley circulation would cause poleward shift of the subtropical dry zone. Various metrics have been applied to measure the widening of the tropics. What are responsible for the observed widening trends of the Hadley circulation? How anthropogenic and natural forcings caused the widening? How the widening results in regional climatic effects? These are the major questions in studies of the Hadley circulation. While both observations and simulations all show widening of the Hadley circulation in the past few decades, there are no general agreements of changes in the strength of the Hadley circulation. Although some reanalysis datasets show strengthening of the Hadley circulation, it was shown that the strengthening trend could be due to artificial reasons, and simulations show weakening of the Hadley circulation for global greenhouse warming. In the present paper, we shall briefly review the major progresses of studies in trends in width and strength of the Hadley circulation. We address answers to these questions, clarify inconsistent results, and propose ideas for future studies.

    更新日期:2018-04-28
  • Evidence for a Dirac nodal-line semimetal in SrAs3
    Sci. Bull. (IF 4) Pub Date : 2018-04-26
    Shichao Li, Zhaopeng Guo, Dongzhi Fu, Xing-Chen Pan, Jinghui Wang, Kejing Ran, Song Bao, Zhen Ma, Zhengwei Cai, Rui Wang, Rui Yu, Jian Sun, Fengqi Song, Jinsheng Wen

    Dirac nodal-line semimetals with the linear bands crossing along a line or loop, represent a new topological state of matter. Here, by carrying out magnetotransport measurements and performing first-principle calculations, we demonstrate that such a state has been realized in high-quality single crystals of SrAs3. We obtain the nontrivial π π Berry phase by analysing the Shubnikov-de Haas quantum oscillations. We also observe a robust negative longitudinal magnetoresistance induced by the chiral anomaly. Accompanying first-principles calculations identifies that a single hole pocket enclosing the loop nodes is responsible for these observations.

    更新日期:2018-04-26
  • Impact of 1.5°C and 2.0°C Global Warming on Aircraft Takeoff Performance in China
    Sci. Bull. (IF 4) Pub Date : 2018-04-25
    Tianjun Zhou, Liwen Ren, Haiwen Liu, Jingwen Lu

    Associated with global warming, climate extremes such as extreme temperature will significantly increase. Understanding how climate change will impact the airflights is important to the planning of future flight operations. In this study, the impacts of 1.5 and 2 degree’s global warming on the aircraft takeoff performance in China are investigated using a unique climate projection data from an international collaboration project named HAPPI. It is found that the mean summer daily maximum temperature, which is a major factor that affects the flight through changing the aircraft’s takeoff weight, will increase significantly with magnitude less than 1.5°C over most parts of China except for the Tibetan Plateau. The half a degree additional global warming will lead to higher extreme temperature in the arid and semi arid western China, the Tibetan Plateau and the northeastern China, while the change in eastern China is weak. Five airports including Beijing, Shanghai, Kunming, Lasa and Urumqi will see ∼1.0°-2.0°C (1.4°-3.0°C) higher daily maximum temperature under 1.5°C (2.0°C) scenario. The half-degree additional warming will lead to a shift toward higher extreme temperature in these five sites. For both 1.5° and 2.0°C scenarios, the number of weight-restriction days will increase significantly at 3 airports including Beijing, Shanghai, and Lasa. Urumqi will witness an increase of weight-restriction days only in 2.0°C future.

    更新日期:2018-04-25
  • Realization of non-equilibrium process for high thermoelectric performance Sb-doped GeTe
    Sci. Bull. (IF 4) Pub Date : 2018-04-25
    Evariste Nshimyimana, Xianli Su, Hongyao Xie, Wei Liu, Rigui Deng, Tingting Luo, Yonggao Yan, Xinfeng Tang

    Pristine GeTe shows inferior thermoelectric properties around unit due to the large carrier concentration induced by the presence of intrinsic high concentration of Ge vacancy. In this study, we report a thermoelectric figure of merit ZT of 1.56 at 700 K, realized in Sb-doped GeTe based thermoelectric (TE) materials via combined effect of suppression of intrinsic Ge vacancy and Sb doping. The non-equilibrium nature during melt spinning process plays very important role. For one thing, it promotes the homogeneity in Ge1–xSbxTe samples and refines the grain size of the product. Moreover the persistent Ge precipitated as impurity phase in the traditional synthesis process were found to be dissolved back into the GeTe sublattice, accompanying with a drastic suppression of Ge vacancies concentration which in combination with Sb electron doping significantly reduced the inherent carrier concentration in GeTe. Low carrier concentration, approaching the optimum carrier concentration ∼3.74 × 10–20 cm–3 and a high power factor of 4.01 × 10–3 W m–1 K–2 at 750 K were achieved for Ge0.98Sb0.02Te sample. In addition, the enhanced grain boundary phonon scattering by refining the grain size through melt spinning (MS) process, coupled with the intensified alloying phonon scattering via Sb doping leads to low thermal conductivity of 1.53 W m−1 K−1 at 700 K for Ge0.94Sb0.06Te sample. All those contribute to a high ZT value, representing over 50% improvement in the ZT value compared to the Sb free samples, which provides an alternative way for ultrafast synthesis of high performance GeTe based thermoelectric material.

    更新日期:2018-04-25
  • Density gradient ultracentrifugation for colloidal nanostructures separation and investigation
    Sci. Bull. (IF 4) Pub Date : 2018-04-25
    Pengsong Li, Anuj Kumar, Jun Ma, Yun Kuang, Liang Luo, Xiaoming Sun

    In this article, we review the advancement in nanoseparation and concomitant purification of nanoparticles (NPs) by using density gradient ultracentrifugation technique (DGUC) and demonstrated by taking several typical examples. Study emphasizes the conceptual advances in classification, mechanism of DGUC and synthesis-structure-property relationships of NPs to provide the significant clue for the further synthesis optimization. Separation, concentration, and purification of NPs by DGUC can be achieved at the same time by introducing the water/oil interfaces into the separation chamber. We can develop an efficient method “lab in a tube” by introducing a reaction zone or an assembly zone in the gradient to find the surface reaction and assembly mechanism of NPs since the reaction time can be precisely controlled and the chemical environment change can be extremely fast. Finally, to achieve the best separation parameters for the colloidal systems, we gave the mathematical descriptions and computational optimized models as a new direction for making practicable and predictable DGUC separation method. Thus, it can be helpful for an efficient separation as well as for the synthesis optimization, assembly and surface reactions as a potential cornerstone for the future development in the nanotechnology and this review can be served as a plethora of advanced notes on the DGUC separation method.

    更新日期:2018-04-25
  • Bifunctional 3D n-doped porous carbon materials derived from paper towel for oxygen reduction reaction and supercapacitor
    Sci. Bull. (IF 4) Pub Date : 2018-04-25
    Xinyu Gao, Xueyan Li, Zhuang Kong, Guozheng Xiao, Ying Zhu

    Designing and fabricating cheap and active bifunctional materials is crucial for the development of renewable energy technologies. In this article, three-dimensional nitrogen-doped porous carbon materials (NDPC-X, in which X represents the pyrolysis temperature) were fabricated by simultaneous carbonization and activation of polypyrrole-coated paper towel protected by a silica layer followed by acid etching. The material had a high specific surface area (1,123.40 m2/g). The as-obtained NDPC-900 displayed outstanding activity as a catalyst for the oxygen reduction reaction (ORR) as well as an electrode with a high specific capacitance in a supercapacitor in an alkaline medium. The NDPC-900 catalyst for the ORR exhibited a more positive reduction peak potential of –0.068 V (vs. Hg|HgCl2) than that of Pt/C (–0.121 V), as well as better cycling stability and stronger methanol tolerance. Moreover, the NDPC-900 had a high specific capacitance of 379.50 F/g at a current density of 1 A/g, with a retention rate of 94.5% after 10,000 cycles in 6 mol/L KOH electrolyte when used as an electrode in a supercapacitor. All these results were attributed to the effect of a large surface area, which provided electrochemically active sites. This work introduces an effective way to use biomass-derived materials for the synthesis of promising bifunctional carbon material for electrochemical energy conversion and storage devices.

    更新日期:2018-04-25
  • Emergent symmetry at superradiance transition of a Bose condensate in two crossed beam cavities
    Sci. Bull. (IF 4) Pub Date : 2018-04-19
    Zhigang Wu, Yu Chen, Hui Zhai

    Recently an experiment on superradiant transition of a Bose condensate in two crossed beam cavities has been reported by Léonard et al. in Nature 543, 87 (2017). The surprise is they find that across the superradiant transition, the cavity light can be emitted in any superposition of these two cavity modes. This indicates an additional U(1) U ( 1 ) symmetry that does not exist in the full Hamiltonian. In this paper we show that this symmetry is an emergent symmetry in the vicinity of the phase transition. We identify all the necessary conditions that are required for this emergent U(1) U ( 1 ) symmetry and show that the this experiment is a special case that satisfies these conditions. We further show that the superradiant transition in this system can also be driven to a first order one when the system is tuned away from the point having the emergent symmetry.

    更新日期:2018-04-25
  • Highly enhanced visible-light photocatalytic NOx purification and conversion pathway on self-structurally modified g-C3N4 nanosheets
    Sci. Bull. (IF 4) Pub Date : 2018-04-19
    Yuhan Li, Yanjuan Sun, Wingkei Ho, Yuxin Zhang, Hongwei Huang, Qiang Cai, Fan Dong

    The unmodified graphitic carbon nitride (g-C3N4) suffers from low photocatalytic activity because of the unfavourable structure. In the present work, we reported a simple self-structural modification strategy to optimize the microstructure of g-C3N4 and obtained graphene-like g-C3N4 nanosheets with porous structure. In contrast to traditional thermal pyrolysis preparation of g-C3N4, the present thermal condensation was improved via pyrolysis of thiourea in an alumina crucible without a cover, followed by secondary heat treatment. The popcorn-like formation and layer-by-layer thermal exfoliation of graphene-like porous g-C3N4 was proposed to explain the formation mechanism. The photocatalytic removal performance of both NO and NO2 with the graphene-like porous g-C3N4 for was significantly enhanced by self-structural modification. Trapping experiments and in-situ diffuse reflectance infrared fourier transform spectroscopy (DRIFTS) measurement were conducted to detect the active species during photocatalysis and the conversion pathway of g-C3N4 photocatalysis for NOx purification was revealed. The photocatalytic activity of graphene-like porous g-C3N4 was highly enhanced due to the improved charge separation and increased oxidation capacity of the ∙O2− radicals and holes. This work could not only provide a novel self-structural modification for design of highly efficient photocatalysts, but also offer new insights into the mechanistic understanding of g-C3N4 photocatalysis.

    更新日期:2018-04-25
  • Towards the manipulation of topological states of matter: a perspective from electron transport
    Sci. Bull. (IF 4) Pub Date : 2018-04-18
    Cheng Zhang, Hai-Zhou Lu, Shun-Qing Shen, Yong P. Chen, Faxian Xiu

    The introduction of topological invariants, ranging from insulators to metals, has provided new insights into the traditional classification of electronic states in condensed matter physics. A sudden change in the topological invariant at the boundary of a topological nontrivial system leads to the formation of exotic surface states that are dramatically different from its bulk. In recent years, significant advancements in the exploration of the physical properties of these topological systems and regarding device research related to spintronics and quantum computation have been made. Here, we review the progress of the characterization and manipulation of topological phases from the electron transport perspective and also the intriguing chiral/Majorana states that stem from them. We then discuss the future directions of research into these topological states and their potential applications.

    更新日期:2018-04-25
  • N-doped defective carbon with trace Co for efficient rechargeable liquid electrolyte- /all-solid-state Zn-air batteries
    Sci. Bull. (IF 4) Pub Date : 2018-04-18
    Zhiyan Chen, Qichen Wang, Xiaobin Zhang, Yongpeng Lei, Wei Hu, Yao Luo, Yaobing Wang

    Simple synthesis of multifunctional electrocatalysts with plentiful active sites from earth-abundant materials is especially fascinating. Here, N-doped defective carbon with trace Co (1.5 wt.%) was prepared via a scalable one pot solid pyrolysis process. The sample exhibits efficient bifunctional OER/ORR activity in alkaline, mainly ascribed to the unique micro-mesoporous structure (1−3 nm), high population of graphitic-N doping (up to 49.0%), abundant defects and the encapsulated Co nanoparticles with graphitized carbon. The according rechargeable liquid Zn-air batteries showed excellent performance (maximum power density of 154.0 mW cm−2; energy density of 773 Wh kg−1 at 5 mA cm−2 and charging-discharging cycling stability over 100 cycles). As a proof-of-concept, the flexible, rechargeable all-solid-state Zn-air batteries were constructed, and displayed a maximum power density as high as 45.9 mW cm−2, among the top level of those reported previously.

    更新日期:2018-04-25
  • Enhancing photocatalytic performance by constructing ultrafine TiO2 nanorods/g-C3N4 nanosheets heterojunction for water treatment
    Sci. Bull. (IF 4) Pub Date : 2018-04-12
    Shiliang Luan, Dan Qu, Li An, Wenshuai Jiang, Xiang Gao, Shixin Hua, Xiang Miao, Yuanjing Wen, Zaicheng Sun

    Photocatalysis is treated as a clean, green and efficient way to water purification. In this report, we first developed a highly efficient ultrafine TiO2 nanorods/g-C3N4 nanosheets (TiO2 NR/CN NS) composites via a simple hydrothermal method. Tiny TiO2 nanorods (diameter: ∼1.5 nm and length: ∼8.3 nm) were first in situ loaded on the CN NS by adding g-C3N4 into the reaction solution. The TiO2 NR/CN NS composites present high charge separation efficiency and broader light absorbance than P25 TiO2. Furthermore, we illustrate that TiO2 NR/CN NS catalyst possesses high performance for the photocatalytic degradation of the common and stubborn pollutants in the water, such as the rhodamine B (RhB) and the phenol. Under the visible light (λ > 420 nm) irradiation, the apparent rate of the TiO2 NR/CN NR is 172 and 41 times higher than that of the P25 TiO2, and TiO2 NR, respectively. As well as, we have speculated that the heterojunction formed between TiO2 NR and CN NS, the basis for the experiments we have designed and the corresponding results. That is, the reactive oxidative species like superoxide anion radical and holes play critical roles in the degradation, the hydroxyl radical has no contribution to the degradation.

    更新日期:2018-04-17
  • A large-sized basal ankylopollexian from East Asia, shedding light on early biogeographic history of Iguanodontia
    Sci. Bull. (IF 4) Pub Date : 2018-04-12
    Xing Xu, Qingwei Tan, Yilong Gao, Zhiqiang Bao, Zhigang Yin, Bin Guo, Junyou Wang, Lin Tan, Yuguang Zhang, Hai Xing

    A presumably mostly quadrupedal ankylopollexian iguanodontian, Bayannurosaurus perfectus gen. et sp. nov., is reported here, and is represented by an excellently well-preserved skeleton from the Lower Cretaceous Bayingebi Formation of Inner Mongolia, China. The diagnosis of the taxon includes several autapomorphies, notably a dorsally directed, strap-like posterodorsal process of the jugal and a horizontally oriented preacetabular process of the ilium. The nearly complete caudal series retains eight posterior-most caudals with procoelous, trapezoidal centra in dorsal view, and the last three caudals are fully fused. The discovery of B. perfectus opens a critical new window on the early evolution and intercontinental dispersal of Iguanodontia. The skeleton displays a transitional morphology between non-hadrosauriform ankylopollexians and Hadrosauriformes. A phylogenetic analysis indicates that Bayannurosaurus is positioned higher on the tree than Hypselospinus, but below Ouranosaurus just outside of Hadrosauriformes. The tree topology of Iguanodontia with temporal and spatial constraints reveals a possible biogeographic scenario supported by the statistical dispersal-vicariance analysis: around the J/K boundary, non-hadrosauriform ankylopollexians experienced multiple dispersal events from Europe to Asia, accompanying the coeval fall of the global sea level.

    更新日期:2018-04-17
  • Astronomical tuning and magnetostratigraphy of Neogene biogenic reefs in Xisha Islands, South China Sea
    Sci. Bull. (IF 4) Pub Date : 2018-04-12
    Liang Yi, Zhimin Jian, Xinyu Liu, Youhua Zhu, Daojun Zhang, Zhenfeng Wang, Chenglong Deng
    更新日期:2018-04-12
  • Highly sensitive wearable sensor based on a flexible multi-layer graphene film antenna
    Sci. Bull. (IF 4) Pub Date : 2018-04-03
    Danli Tang, Qianlong Wang, Zhe Wang, Quantao Liu, Bin Zhang, Daping He, Zhi Wu, Shichun Mu
    更新日期:2018-04-03
  • 更新日期:2018-04-03
  • PCL2 regulates p53 stability and functions as a tumor suppressor in breast cancer
    Sci. Bull. (IF 4) Pub Date : 2018-03-30
    Yiran Liang, Yang Yang, Renbo Guo, Shuang Gao, Xinghong Guo, Danyang Li, Meng Wang, Haruhiko Koseki, Xiangzhi Li

    Polycomblike2 (PCL2) is a well-known component of polycomb repressive complex 2 (PRC2) and plays important roles in H3K27 methylation and homeotic gene silencing. However, the involvement of PCL2 in breast cancer development remains unclear. Here, we established PCL2 as a tumor suppressor gene in breast cancer. Expression level of PCL2 was significantly downregulated in breast cancer tissue samples observed at different TNM stages. Ectopic expression of PCL2 could significantly inhibit cell proliferation and promoted apoptosis. PCL2 also remarkably elevated levels of p53 and its targets by increasing p53 stability. Mechanistically, PCL2 protected p53 proteins from MDM2-mediated ubiquitination and degradation by sequestering MDM2 into the nucleolus. Overexpression of PCL2 also suppressed migration and invasion by inhibiting epithelial-mesenchymal transition. PCL2 expression was correlated with E-cadherin expression and was inversely correlated with vimentin expression. Furthermore, PCL2 knockdown could attenuate anti-tumor effect of MLN4924. Taken together, our findings indicated that PCL2 played a tumor suppressor role in development and progression of breast cancer and may be a prognostic and predictive marker for breast cancer.

    更新日期:2018-03-30
  • Multimetallic AuPd@Pd@Pt core-interlayer-shell icosahedral electrocatalysts for highly efficient oxygen reduction reaction
    Sci. Bull. (IF 4) Pub Date : 2018-03-26
    Qingfeng Xu, Wenlong Chen, Yucong Yan, Zhemin Wu, Yi Jiang, Junjie Li, Ting Bian, Hui Zhang, Jianbo Wu, Deren Yang
    更新日期:2018-03-26
  • Temperature variability in Northern Iran during the past 700 years
    Sci. Bull. (IF 4) Pub Date : 2018-03-23
    Vilma Bayramzadeh, Haifeng Zhu, Xiaoming Lu, Pedram Attarod, Hui Zhang, Xiaoxia Li, Fayaz Asad, Eryuan Liang
    更新日期:2018-03-24
  • Magnetic-field enhanced high-thermoelectric performance in topological Dirac semimetal Cd3As2 crystal
    Sci. Bull. (IF 4) Pub Date : 2018-03-21
    Honghui Wang, Xigang Luo, Weiwei Chen, Naizhou Wang, Bin Lei, Fanbao Meng, Chao Shang, Likuan Ma, Tao Wu, Xi Dai, Zhengfei Wang, Xianhui Chen
    更新日期:2018-03-22
  • Unveiling the charge density wave inhomogeneity and pseudogap state in 1T-TiSe2
    Sci. Bull. (IF 4) Pub Date : 2018-03-21
    Kai-Wen Zhang, Chao-Long Yang, Bin Lei, Pengchao Lu, Xiang-Bing Li, Zhen-Yu Jia, Ye-Heng Song, Jian Sun, Xianhui Chen, Jian-Xin Li, Shao-Chun Li
    更新日期:2018-03-22
  • The development of MOFs-based nanomaterials in heterogeneous organocatalysis
    Sci. Bull. (IF 4) Pub Date : 2018-03-20
    Xiaomei Liu, Bing Tang, Jilan Long, Wei Zhang, Xiaohong Liu, Zakaria Mirza
    更新日期:2018-03-22
  • Epitaxially grown monolayer VSe2: an air-stable magnetic two-dimensional material with low work function at edges
    Sci. Bull. (IF 4) Pub Date : 2018-03-20
    Zhong-Liu Liu, Xu Wu, Yan Shao, Jing Qi, Yun Cao, Li Huang, Chen Liu, Jia-Ou Wang, Qi Zheng, Zhi-Li Zhu, Kurash Ibrahim, Ye-Liang Wang, Hong-Jun Gao
    更新日期:2018-03-22
  • Experimental demonstration of nonlinear quantum metrology with optimal quantum state
    Sci. Bull. (IF 4) Pub Date : 2018-03-20
    Xinfang Nie, Jiahao Huang, Zhaokai Li, Wenqiang Zheng, Chaohong Lee, Xinhua Peng, Jiangfeng Du

    Nonlinear quantum metrology may exhibit better precision scalings. For example, the uncertainty of an estimated phase may scale as Δϕ∝1/N2 Δ ϕ ∝ 1 / N 2 under quadratic phase accumulation, which is 1/N 1 / N times smaller than the linear counterpart, where N is probe number. Here, we experimentally demonstrate the nonlinear quantum metrology by using a spin-I (I>1/2 I > 1 / 2 ) nuclear magnetic resonance (NMR) ensemble that can be mapped into a system of N=2I N = 2 I spin-1/2 1 / 2 particles and the quadratic interaction can be utilized for the quadratic phase accumulation. Our experimental results show that the phase uncertainty can scale as Δϕ∝1/(N2-1) Δ ϕ ∝ 1 / ( N 2 - 1 ) by optimizing the input states, when N is an odd number. In addition, the interferometric measurement with quadratic interaction provides a new way for estimating the quadrupolar coupling strength in an NMR system. Our system may be further extended to exotic nonlinear quantum metrology with higher order many-body interactions.

    更新日期:2018-03-20
  • Prevalence and treatment of hypertension in China: impacts of 2017 American College of Cardiology/American Heart Association High Blood Pressure Guideline
    Sci. Bull. (IF 4) Pub Date : 2018-03-15
    Chao Yang, Jinwei Wang, Bixia Gao, Yan Zhang, Fang Wang, Luxia Zhang, Minghui Zhao, Yong Huo

    The definition, recommended treatment thresholds and targets of hypertension have been updated in the recent 2017 American College of Cardiology/American Heart Association (ACC/AHA) Guideline for the Prevention, Detection, Evaluation and Management of High Blood Pressure in Adults. However, the impacts of this guideline on Chinese population are currently unknown. In this study, we aim to provide updated data in China using criteria from the updated guideline. A multistage, stratified sampling method was used to obtain a representative sample of 50,171 adults aged 18 years and above. Hypertension was defined as an average systolic blood pressure ≥130 mm Hg, or an average diastolic blood pressure ≥80 mm Hg, or self-reported use of antihypertensive medications in past 2 weeks. The weighted prevalence of hypertension was 60.1% (95% confidence interval [CI] 59.3%-61.0%). The treatment rate and recommended treatment rates were 16.8% (95% CI 16.1%-17.6%) and 53.7% (95% CI 52.6%-54.9%), respectively; the gap was more prominent among men and participants from rural areas. Hence, the adoption of the 2017 ACC/AHA guideline will lead to a substantial increase in both prevalence and number of patients needing treatment in China. The applicability of this guideline should be carefully evaluated based on evidence from Chinese population.

    更新日期:2018-03-15
  • Emerging disciplines based on superatoms: a perspective point of view
    Sci. Bull. (IF 4) Pub Date : 2018-03-15
    Jianpeng Wang, Weiyu Xie, Yang Gao, Dexuan Xu, Zhigang Wang
    更新日期:2018-03-15
  • Inhibition of BET selectively eliminates undifferentiated pluripotent stem cells
    Sci. Bull. (IF 4) Pub Date : 2018-03-15
    Jung Hyun Im, Seon In Hwang, Jong-Wan Kim, Soon-Jung Park, Kyu-ree Kang, Jueng Soo You, Kee Pyo Kim, Sung-Hwan Moon, Hyuk-Jin Cha, Hyung-Min Chung, Hans R. Schöler, Jung Keun Hyun, Dong Wook Han

    Embryonic stem cells (ESCs) maintain their cellular identity through the systematic regulation of master transcription factors and chromatin remodeling complexes. Recent work has shown that the unusually large-scale enhancers—namely super-enhancers (SEs), on which BRD4, a member of the bromodomain and extraterminal domain (BET) family is highly enriched—could regulate pluripotency-related transcription factors. Moreover, inhibition of BRD4 binding on SEs has been shown to induce the differentiation of ESCs. However, the underlying mechanism of BRD4 inhibition–mediated stem cell differentiation remains elusive. Here we show that both mouse and human ESCs lose their capacity for self-renewal upon treatment with JQ1, a selective inhibitor of BET family including BRD4, with rapid suppression of pluripotency-associated genes. Notably, a high concentration of JQ1 could selectively eliminate ESCs via apoptosis, without affecting the functionality of differentiated somatic cells from ESCs, suggesting that inhibition of BET may have a beneficial effect on the development of pluripotent stem cell–based cell therapy.

    更新日期:2018-03-15
  • 更新日期:2018-03-13
  • 更新日期:2018-03-11
  • Appending triphenyltriazine to 1,10-phenanthroline: a robust electron-transport material for stable organic light-emitting diodes
    Sci. Bull. (IF 4) Pub Date : 2018-03-10
    Guang Jin, Jun-Zhe Liu, Jian-Hua Zou, Xiao-Lan Huang, Meng-Jiao He, Ling Peng, Ling-Ling Chen, Xu-Hui Zhu, Junbiao Peng, Yong Cao
    更新日期:2018-03-11
  • A vicinal effect for promoting catalysis of Pd1/TiO2: supports of atomically dispersed catalysts play more roles than simply serving as ligands
    Sci. Bull. (IF 4) Pub Date : 2018-03-10
    Pengxin Liu, Yun Zhao, Ruixuan Qin, Lin Gu, Peng Zhang, Gang Fu, Nanfeng Zheng
    更新日期:2018-03-11
  • s-p orbital hybridization: a strategy for developing efficient photocatalysts with high carrier mobility
    Sci. Bull. (IF 4) Pub Date : 2018-03-02
    Zhong-Fei Xu, Kang Xu, Hai-Feng Feng, Yi Du, Wei-Chang Hao
    更新日期:2018-03-02
  • N-rich covalent organic polymer in situ modified TiO2 for highly efficient photocatalytic hydrogen evolution
    Sci. Bull. (IF 4) Pub Date : 2018-02-15
    Zhuohang Zhou, Peng Peng, Zhonghua Xiang

    TiO2 has been everlastingly employed as popular photocatalyst for water splitting. However, the wide band gap (3.0-3.2 eV) and poor absorption to visible light of TiO2 result in a low utilization of solar energy and limit its large-scale application. To decrease its band gap and promote the utilization of full solar energy, we here modified TiO2 by in situ growth of N-rich covalent organic polymer (termed as COPHM). During the in situ growth of COPHM on the surface of TiO2, intimate contacts between TiO2 and COPHM were built and core-shell structures were finally formed. The derived TiO2@COPHM demonstrated a narrower band gap (2.53 eV) compared to raw TiO2 (3.13 eV) and improved absorption to visible light. The optimal TiO2@COPHM hybrid exhibited excellent hydrogen evolution performance of 162.7 μmol h-1 under simulated sunlight which was more than 3 times higher than raw TiO2 (51.3 μmol h-1). Particularly, visible light hydrogen evolution rate of TiO2@COPHM reached 0.65 μmol h-1 while non-hydrogen generation was observed using raw TiO2.

    更新日期:2018-02-15
  • High electrocaloric cooling power of relaxor ferroelectric BaZrxTi1–xO3 ceramics within broad temperature range
    Sci. Bull. (IF 4) Pub Date : 2018-02-14
    Jianfeng Qian, Penghao Hu, Chen Liu, Jianyong Jiang, Zhenkang Dan, Jing Ma, Yuanhua Lin, Ce-Wen Nan, Yang Shen

    Electrocaloric effect (ECE) is much promising to realize high efficiency and environment friendly solution in solid cooling devices. Relaxor ferroelectrics are good candidates for the materials with high electrocaloric cooling power. In this paper, relaxor ferroelectric Ba(ZrxTi1–x)O3 (BZT, x = 0.2, 0.21, 0.22, 0.23) ceramics were prepared with their temperature change (ΔT) induced by the ECE and electrocaloric strength (ΔT/E) measured within broad temperature range. It is found that the BZT21 (x = 0.21) exhibits the largest ΔT of ∼ 4.67 K and a high ΔT/E value of ∼ 0.46 Km/MV at 9.9 MV/m and 25 °C. BZT21 also exhibits apparent relaxor ferroelectric response, showing a very broad EC peak in the temperature interval between 15 °C to 50 °C. Moreover, the relationship between EC properties and relaxor features was analyzed by piezoresponse force microscopy test. The results reveal that more dispersed phase structures induce additional configurational entropy, which is in favor for the enhanced EC performance. The interplay and compromise between the kinetic and thermodynamic mechanisms of domain switching determines the optimal composition for the EC performances of the BZT ceramics.

    更新日期:2018-02-14
  • One-pot synthesis of nickel-cobalt hydroxyfluorides nanowires with ultrahigh energy density for an asymmetric supercapacitor
    Sci. Bull. (IF 4) Pub Date : 2018-02-13
    Jian-Fang Zhang, Yan Wang, Xia Shu, Cui-Ping Yu, Ming-Feng Xiao, Jie-Wu Cui, Yong-Qiang Qin, Hong-Mei Zheng, Yong Zhang, Dong Chen, Pulickel M. Ajayan, Yu-Cheng Wu

    A novel and unique nickel-cobalt hydroxyfluorides (NiCo-HF) nanowires material is fabricated by one-pot solvothermal synthesis method for asymmetric supercapacitor. The synthesis mechanism and factors that influence the formation of the NiCo-HF nanowires have been further discussed. The as-prepared NiCo-HF electrode exhibits a high specific capacitance of 3,372.6 F g−1, and the capacitance retention of 94.3% can be achieved at a high current density of 20 A g−1 after 10,000 cycles. The outstanding electrochemical performance of the electrode can be attributed to the synergistic effect of the nanowires morphology and complicated redox process of active material. Furthermore, an asymmetric supercapacitor assembled with NiCo-HF nanowires as positive electrode and activated carbon as the negative electrode shows an ultrahigh energy density of 83.6 Wh kg−1 at a power density of 379.4 W kg−1 and an excellent cycling stability with 86.3% capacitance retention after 10,000 cycles, indicating that this novel material has great promise for potential application in energy storage device.

    更新日期:2018-02-14
  • Cation-mixing stabilized layered oxide cathodes for sodium-ion batteries
    Sci. Bull. (IF 4) Pub Date : 2018-02-13
    Shaohua Guo, Yang Sun, Pan Liu, Jin Yi, Ping He, Xiaoyu Zhang, Yanbei Zhu, Ryosuke Senga, Kazu Suenaga, Mingwei Chen, Haoshen Zhou
    更新日期:2018-02-13
  • 更新日期:2018-02-13
  • Thermostable single-junction organic solar cells with a power conversion efficiency of 14.62%
    Sci. Bull. (IF 4) Pub Date : 2018-02-13
    Hui Li, Zuo Xiao, Liming Ding, Jizheng Wang
    更新日期:2018-02-13
  • 更新日期:2018-02-08
  • The secret of fertilization in flowering plants unveiled
    Sci. Bull. (IF 4) Pub Date : 2018-02-08
    Xiangxiu Liang, Jian-Min Zhou

    As recapitulated in the famous Chinese fairy tale Journey to the West, the Buddhist monk Xuanzang of the Tang Dynasty (Tangseng) took a heroic journey in a quest for India Buddhist sacred scriptures. The long and dangerous journey was made possible only with the help of the powerful monkey king, who had been pinned down under a mountain by the Buddha as a punishment for his prior misdemeanor. The Buddha had to secure the mountain with a magic paper seal so that the monkey king would not break loose. The monkey king burst out from the mountain as soon as Tangseng lifted the seal, so that he could escort Tangseng through the journey.

    更新日期:2018-02-08
  • Heterostructure TiO2 polymorphs design and structure adjustment for photocatalysis
    Sci. Bull. (IF 4) Pub Date : 2018-02-08
    Di He, Heng Su, Xue Qiao Li, Hai Jun Yu, Muhammad Zubair, Lin Wang, Sheng Cheng Mao, Jin Shu Wang

    Atomic composite-structure materials play an important role in energy generation and storage application fields for their advanced performance. Constructing heterostructured semiconductors is a promising strategy to devise photocatalytic systems with high activity. However, most studied hererostructures are those semiconductors with different materials formed by multi-steps, researches on in-situ formed hererostructure originated from the same precursor are few reported, and the effects of different structure ratios on photocatalytic performance are ambiguous. Here, according to in-situ temperature X-ray diffraction and transmission electron microscope techniques, a nano-sized in-situ formed heterostructure of TiO2 semiconductors with anatase and TiO2-B crystalline structures were designed, their structure ratios were adjusted, the heterostructure interface and photocatalytic reaction mechanism were also detected. Results show that high-quality heterojunction and optimum structure ratios have vital influence on photocatalytic performance, there is an obvious synergetic effect between anatase and TiO2-B structure, degradation reactions on methyl orange (MO) under ultraviolet light irradiation prove that the highest activity toward MO removal can be obtained for material with 82.5% anatase structure.

    更新日期:2018-02-08
  • Application of microprobe-based flank method analysis of Fe3+ in garnet of North Qilian eclogite and its geological implication
    Sci. Bull. (IF 4) Pub Date : 2018-02-06
    Li Xiaoli, Song Shuguang, Zhang Lifei, E. Höfer Heidi

    A newly developed microprobe-based methodology (the Flank Method) for Fe3+/ΣFe quantification has been successfully applied to some natural garnets from the North Qilian eclogites by JEOL JXA-8100 microprobe at Peking University. The results demonstrated an obvious discrepancy in comparison with the outcomes by conventional stoichiometric calculations. This methodology allows to measure the Fe3+/ΣFe ratio and perform elemental analyses simultaneously in the same condition. Accurate in-situ measurement of Fe3+ content in garnet may bring certain impact on the garnet-based P-T estimation. According to the compositional zonation displayed in the studied eclogitic garnets from North Qilian, a prograde metamorphic PT path from 19.5 kbar, 520 °C to 22 kbar, 600 °C was reconstructed. More interestingly, the measured Fe3+/ΣFe ratios in garnets decreasing from core to rim may probably imply that the oxygen fugacity (fO2) declines with the depth of the subduction zone.

    更新日期:2018-02-06
  • Experimental realization of honeycomb borophene
    Sci. Bull. (IF 4) Pub Date : 2018-02-05
    Wenbin Li, Longjuan Kong, Caiyun Chen, Jian Gou, Shaoxiang Sheng, Weifeng Zhang, Hui Li, Lan Chen, Peng Cheng, Kehui Wu
    更新日期:2018-02-06
  • ZnO-PCBM bilayers as electron transport layers in low-temperature fabricated perovskite solar cells
    Sci. Bull. (IF 4) Pub Date : 2018-02-05
    Jiaqi Zhang, Ching Hong Tan, Tian Du, Maurizio Morbidoni, Chieh-Ting Lin, Shengda Xu, James R. Durrant, Martyn A. McLachlan
    更新日期:2018-02-06
  • Rapid and high precision measurement of opto-thermal relaxation with pump-probe method
    Sci. Bull. (IF 4) Pub Date : 2018-02-05
    Tao Wang, Xiaofei Liu, Yunqi Hu, Guoqing Qin, Dong Ruan, Gui-Lu Long
    更新日期:2018-02-06
  • Simulation of molecular spectroscopy with circuit quantum electrodynamics
    Sci. Bull. (IF 4) Pub Date : 2018-02-05
    Ling Hu, Yue-Chi Ma, Yuan Xu, Wei-Ting Wang, Yu-Wei Ma, Ke Liu, Hai-Yan Wang, Yi-Pu Song, Man-Hong Yung, Lu-Yan Sun

    Spectroscopy is a crucial laboratory technique for understanding quantum systems through their interactions with the electromagnetic radiation. Particularly, spectroscopy is capable of revealing the physical structure of molecules, leading to the development of the maser—the forerunner of the laser. However, real-world applications of molecular spectroscopy are mostly confined to equilibrium states, due to computational and technological constraints; a potential breakthrough can be achieved by utilizing the emerging technology of quantum simulation. Here we experimentally demonstrate through a toy model, a superconducting quantum simulator capable of generating molecular spectra for both equilibrium and non-equilibrium states, reliably producing the vibronic structure of diatomic molecules. Furthermore, our quantum simulator is applicable not only to molecules with a wide range of electronic-vibronic coupling strength, characterized by the Huang-Rhys parameter, but also to molecular spectra not readily accessible under normal laboratory conditions. These results point to a new direction for predicting and understanding molecular spectroscopy, exploiting the power of quantum simulation.

    更新日期:2018-02-05
  • Much late onset of Quaternary glaciations on the Tibetan Plateau: determining the age of the Shishapangma Glaciation using cosmogenic 26Al and 10Be dating
    Sci. Bull. (IF 4) Pub Date : 2018-02-03
    Yixin Chen, Yingkui Li, Mei Zhang, Zhijiu Cui, Gengnian Liu

    The onset of Quaternary glaciations is a critical event in the climate and tectonic history of the Tibetan Plateau. The Shishapangma Glaciation, defined based on the till deposit from the northern slopes of Mt. Shishapangma, has been identified as the oldest glaciation on the Tibetan Plateau. However, the timing of this glaciation has not been constrained. We measured 10Be and 26Al concentrations of a set of boulders on top of this till and simulated their complex exposure-burial histories. The simulated results indicate that the formation age of this till is likely around 835.2 ± 241.0 ka, representing the minimum timing of glacial onset on the Tibetan Plateau. The Shishapangma Glaciation is apparently much younger than the glacial onset in many other areas of the world, such as Europe and North America, and was likely driven by the coupled effect between tectonic uplift and climate cooling during the early–middle Pleistocene transition.

    更新日期:2018-02-04
  • A flattened enantiornithine in mid-Cretaceous Burmese amber: Morphology and preservation
    Sci. Bull. (IF 4) Pub Date : 2018-01-31
    Lida Xing, Jingmai K. O'Connor, Ryan C. McKellar, Luis M. Chiappe, Ming Bai, Kuowei Tseng, Jie Zhang, Haidong Yang, Jun Fang, Gang Li

    Cretaceous amber from Myanmar (∼99 Ma Burmese amber) has become a valuable supplement to the traditional skeletal record of small theropod dinosaurs preserved in sedimentary rocks, particularly for coelurosaurs and enantiornithines. The specimens recovered from this deposit preserve skeletal material and soft tissues in unmatched detail. This provides opportunities to study three-dimensional preservation of soft tissues, microstructure, and pigmentation patterns that are seldom available elsewhere in the fossil record. Ultimately, this line of research provides insights into life stages that are difficult to preserve, the ecology and appearance of the groups involved, and the evolutionary-development of structures such as feathers. Here we describe the most recent discovery from Burmese amber, an articulated skeleton of an enantiornithine bird. This individual has been sectioned along the coronal plane, providing a unique view inside multiple body regions. Osteological observations and plumage patterns support placement within the Enantiornithes, and suggest that the animal may have been a juvenile at the time of death. The specimen has a complex taphonomic history that includes exposure at the surface of a resin flow prior to encapsulation, and may include scavenging by some of the insects trapped within the same amber piece. The chemical composition observed along surface exposures and shallowly buried regions of the body indicate that the specimen has not undergone significant exchange with its surroundings. High iron concentrations are present in regions that preserve soft tissues as carbon films, and calcium distribution corresponds to regions where bones breach the surface of the amber.

    更新日期:2018-02-02
  • Versatile design and synthesis of mesoporous sulfonic acid catalysts
    Sci. Bull. (IF 4) Pub Date : 2018-01-31
    Peng Wang, Yupei Zhao, Jian Liu
    更新日期:2018-02-02
  • Dynamic deformation behavior of a face-centered cubic FeCoNiCrMn high-entropy alloy
    Sci. Bull. (IF 4) Pub Date : 2018-01-31
    Junyang He, Qi Wang, Husheng Zhang, Lanhong Dai, Toshiji Mukai, Yuan Wu, Xiongjun Liu, Hui Wang, Tai-Gang Nieh, Zhaoping Lu
    更新日期:2018-02-02
  • Barium isotope cosmochemistry and geochemistry
    Sci. Bull. (IF 4) Pub Date : 2018-01-31
    Quentin Charbonnier, Frédéric Moynier, Julien Bouchez

    While the isotopic variations of barium were reported for the first time fourty years ago, the number of studies on barium isotopes significantly increased only after 2010. Barium isotope anomalies in meteorites have been successfully used to provide constraints about the origin of presolar SiC grains. In carbonaceous chondrites Ba isotope anomalies are indicative of the heterogeneity of the early solar system, possibly resulting from of a later injection of material after the cooling of solar system. Barium isotope fractionation in the same carbonaceous chondrites suggests that a strong magnetic field was present in the innermost part of the early solar system. Barium mass-dependent isotope fractionation has also been detected throughout Earth surface materials. While igneous rocks show limited Ba isotopic variations, relatively large isotopic variations are observed amongst and within soils, rivers, and biological materials. Indeed, plants seem to fractionate Ba isotopes during Ba uptake from soil solutions. Therefore, Ba isotope signatures have the potential to provide clues on the biological cycling of Ba at the Earth surface. In seawater, Ba isotopic variations have been mapped out, and are mainly related to barite precipitation, which is in turn related to organic matter remineralization in the water column. This makes Ba isotopes a potentially powerful tool to reconstruct past ocean productivity, although constraints are still lacking regarding the inputs of dissolved Ba to the oceans by rivers or hydrothermalism.

    更新日期:2018-02-02
  • Ordered mesoporous NiFe2O4 with ultrathin framework for low-ppb toluene sensing
    Sci. Bull. (IF 4) Pub Date : 2018-01-12
    Xiaoyong Lai, Kun Cao, Guoxin Shen, Ping Xue, Dan Wang, Fang Hu, Jianli Zhang, Qingfeng Yang, Xiaozhong Wang
    更新日期:2018-01-12
  • How heteroatoms (Ge, N, P) improve the electrocatalytic performance of graphene: theory and experiment
    Sci. Bull. (IF 4) Pub Date : 2018-01-12
    Guojing Chang, Jun Ren, Xilin She, Kewei Wang, Sridhar Komarneni, Dongjiang Yang
    更新日期:2018-01-12
  • Porous carbon supported atomic iron as electrocatalysts for acidic oxygen reduction reaction
    Sci. Bull. (IF 4) Pub Date : 2018-01-12
    Peiwen Yu, Renjie Chen, Qiao Zhang, Sihui Liang, Mei Ni, Wen Yang
    更新日期:2018-01-12
  • Fabrication and luminescence of KGdF4:Yb3+/Er3+ nanoplates and their improving performance for polymer solar cells
    Sci. Bull. (IF 4) Pub Date : 2018-01-11
    Jiqing Jiao, Yao Li, Wenfei Shen, Shasha Gai, Jianguo Tang, Yao Wang, Linjun Huang, Jixian Liu, Wei Wang, Laurence A. Belfiore
    更新日期:2018-01-12
  • Few-layer Tellurium: one-dimensional-like layered elementary semiconductor with striking physical properties
    Sci. Bull. (IF 4) Pub Date : 2018-01-09
    Jingsi Qiao, Yuhao Pan, Feng Yang, Cong Wang, Yang Chai, Wei Ji
    更新日期:2018-01-10
  • Observations of the step-like accelerating processes of cold ions in the reconnection layer at the dayside magnetopause
    Sci. Bull. (IF 4) Pub Date : 2018-01-05
    Qing-He Zhang, Michael Lockwood, John C. Foster, Qiu-Gang Zong, Malcolm W. Dunlop, Shun-Rong Zhang, Jøran Moen, Bei-Chen Zhang

    Cold ions of plasmaspheric origin have been observed to abundantly appear in the magnetospheric side of the Earth’s magnetopause. These cold ions could affect the magnetic reconnection processes at the magnetopause by changing the Alfvén velocity and the reconnection rate, while they could also be heated in the reconnection layer during the ongoing reconnections. We report in situ observations from a partially crossing of a reconnection layer near the subsolar magnetopause. During this crossing, step-like accelerating processes of the cold ions were clearly observed, suggesting that the inflow cold ions may be separately accelerated by the rotation discontinuity and slow shock inside the reconnection layer.

    更新日期:2018-01-06
Some contents have been Reproduced with permission of the American Chemical Society.
Some contents have been Reproduced by permission of The Royal Society of Chemistry.
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