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  • 1
    Publication Date: 2012-11-23
    Description: Synchronization occurs widely in the natural and technological worlds, from the rhythm of applause and neuron firing to the quantum mechanics of coupled Josephson junctions, but has not been used to produce new spatial structures. Our understanding of self-assembly has evolved independently in the fields of chemistry and materials, and with a few notable exceptions has focused on equilibrium rather than dynamical systems. Here we combine these two phenomena to create synchronization-selected microtubes of Janus colloids, micron-sized spherical particles with different surface chemistry on their opposing hemispheres, which we study using imaging and computer simulation. A thin nickel film coats one hemisphere of each silica particle to generate a discoid magnetic symmetry, such that in a precessing magnetic field its dynamics retain crucial phase freedom. Synchronizing their motion, these Janus spheres self-organize into micrometre-scale tubes in which the constituent particles rotate and oscillate continuously. In addition, the microtube must be tidally locked to the particles, that is, the particles must maintain their orientation within the rotating microtube. This requirement leads to a synchronization-induced structural transition that offers various applications based on the potential to form, disintegrate and fine-tune self-assembled in-motion structures in situ. Furthermore, it offers a generalizable method of controlling structure using dynamic synchronization criteria rather than static energy minimization, and of designing new field-driven microscale devices in which components do not slavishly follow the external field.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Yan, Jing -- Bloom, Moses -- Bae, Sung Chul -- Luijten, Erik -- Granick, Steve -- England -- Nature. 2012 Nov 22;491(7425):578-81. doi: 10.1038/nature11619.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Materials Science and Engineering, University of Illinois, Urbana, Illinois 61801, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/23172215" target="_blank"〉PubMed〈/a〉
    Print ISSN: 0028-0836
    Electronic ISSN: 1476-4687
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
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  • 2
    Publication Date: 2015-03-18
    Description: Engineering the electromagnetic environment of a nanometre-scale light emitter by use of a photonic cavity can significantly enhance its spontaneous emission rate, through cavity quantum electrodynamics in the Purcell regime. This effect can greatly reduce the lasing threshold of the emitter, providing a low-threshold laser system with small footprint, low power consumption and ultrafast modulation. An ultralow-threshold nanoscale laser has been successfully developed by embedding quantum dots into a photonic crystal cavity (PCC). However, several challenges impede the practical application of this architecture, including the random positions and compositional fluctuations of the dots, extreme difficulty in current injection, and lack of compatibility with electronic circuits. Here we report a new lasing strategy: an atomically thin crystalline semiconductor--that is, a tungsten diselenide monolayer--is non-destructively and deterministically introduced as a gain medium at the surface of a pre-fabricated PCC. A continuous-wave nanolaser operating in the visible regime is thereby achieved with an optical pumping threshold as low as 27 nanowatts at 130 kelvin, similar to the value achieved in quantum-dot PCC lasers. The key to the lasing action lies in the monolayer nature of the gain medium, which confines direct-gap excitons to within one nanometre of the PCC surface. The surface-gain geometry gives unprecedented accessibility and hence the ability to tailor gain properties via external controls such as electrostatic gating and current injection, enabling electrically pumped operation. Our scheme is scalable and compatible with integrated photonics for on-chip optical communication technologies.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Wu, Sanfeng -- Buckley, Sonia -- Schaibley, John R -- Feng, Liefeng -- Yan, Jiaqiang -- Mandrus, David G -- Hatami, Fariba -- Yao, Wang -- Vuckovic, Jelena -- Majumdar, Arka -- Xu, Xiaodong -- England -- Nature. 2015 Apr 2;520(7545):69-72. doi: 10.1038/nature14290. Epub 2015 Mar 16.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Physics, University of Washington, Seattle, Washington 98195, USA. ; Ginzton Laboratory, Stanford University, Stanford, California 94305, USA. ; 1] Department of Physics, University of Washington, Seattle, Washington 98195, USA [2] Department of Applied Physics, Tianjin University, Tianjin 300072, China. ; 1] Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA [2] Department of Materials Science and Engineering, University of Tennessee, Knoxville, Tennessee 37996, USA. ; 1] Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA [2] Department of Materials Science and Engineering, University of Tennessee, Knoxville, Tennessee 37996, USA [3] Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996, USA. ; Department of Physics, Humboldt University, D-12489 Berlin, Germany. ; Department of Physics and Center of Theoretical and Computational Physics, University of Hong Kong, Hong Kong, China. ; Department of Electrical Engineering, University of Washington, Seattle, Washington 98195, USA. ; 1] Department of Physics, University of Washington, Seattle, Washington 98195, USA [2] Department of Material Science and Engineering, University of Washington, Seattle, Washington 98195, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/25778703" target="_blank"〉PubMed〈/a〉
    Print ISSN: 0028-0836
    Electronic ISSN: 1476-4687
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
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  • 3
    Publication Date: 2013-09-07
    Description: An avian-origin human-infecting influenza (H7N9) virus was recently identified in China. We have evaluated the viral hemagglutinin (HA) receptor-binding properties of two human H7N9 isolates, A/Shanghai/1/2013 (SH-H7N9) (containing the avian-signature residue Gln(226)) and A/Anhui/1/2013 (AH-H7N9) (containing the mammalian-signature residue Leu(226)). We found that SH-H7N9 HA preferentially binds the avian receptor analog, whereas AH-H7N9 HA binds both avian and human receptor analogs. Furthermore, an AH-H7N9 mutant HA (Leu(226) --〉 Gln) was found to exhibit dual receptor-binding property, indicating that other amino acid substitutions contribute to the receptor-binding switch. The structures of SH-H7N9 HA, AH-H7N9 HA, and its mutant in complex with either avian or human receptor analogs show how AH-H7N9 can bind human receptors while still retaining the avian receptor-binding property.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Shi, Yi -- Zhang, Wei -- Wang, Fei -- Qi, Jianxun -- Wu, Ying -- Song, Hao -- Gao, Feng -- Bi, Yuhai -- Zhang, Yanfang -- Fan, Zheng -- Qin, Chengfeng -- Sun, Honglei -- Liu, Jinhua -- Haywood, Joel -- Liu, Wenjun -- Gong, Weimin -- Wang, Dayan -- Shu, Yuelong -- Wang, Yu -- Yan, Jinghua -- Gao, George F -- New York, N.Y. -- Science. 2013 Oct 11;342(6155):243-7. doi: 10.1126/science.1242917. Epub 2013 Sep 5.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Research Network of Immunity and Health, Beijing Institutes of Life Science, Chinese Academy of Sciences, Beijing, China.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/24009358" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Birds ; Crystallography, X-Ray ; Glycine/chemistry/genetics/metabolism ; Hemagglutinin Glycoproteins, Influenza Virus/*chemistry/metabolism ; Humans ; Influenza A virus/*metabolism ; Influenza in Birds/*virology ; Influenza, Human/*virology ; Protein Conformation ; Receptors, Cell Surface/*chemistry/genetics/metabolism
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 4
    Publication Date: 2018-12-14
    Description: Despite progress in defining genetic risk for psychiatric disorders, their molecular mechanisms remain elusive. Addressing this, the PsychENCODE Consortium has generated a comprehensive online resource for the adult brain across 1866 individuals. The PsychENCODE resource contains ~79,000 brain-active enhancers, sets of Hi-C linkages, and topologically associating domains; single-cell expression profiles for many cell types; expression quantitative-trait loci (QTLs); and further QTLs associated with chromatin, splicing, and cell-type proportions. Integration shows that varying cell-type proportions largely account for the cross-population variation in expression (with 〉88% reconstruction accuracy). It also allows building of a gene regulatory network, linking genome-wide association study variants to genes (e.g., 321 for schizophrenia). We embed this network into an interpretable deep-learning model, which improves disease prediction by ~6-fold versus polygenic risk scores and identifies key genes and pathways in psychiatric disorders.
    Keywords: Genetics, Neuroscience, Online Only
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Geosciences , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 5
    Publication Date: 2013-04-05
    Description: The technological demand to push the gigahertz (10(9) hertz) switching speed limit of today's magnetic memory and logic devices into the terahertz (10(12) hertz) regime underlies the entire field of spin-electronics and integrated multi-functional devices. This challenge is met by all-optical magnetic switching based on coherent spin manipulation. By analogy to femtosecond chemistry and photosynthetic dynamics--in which photoproducts of chemical and biochemical reactions can be influenced by creating suitable superpositions of molecular states--femtosecond-laser-excited coherence between electronic states can switch magnetic order by 'suddenly' breaking the delicate balance between competing phases of correlated materials: for example, manganites exhibiting colossal magneto-resistance suitable for applications. Here we show femtosecond (10(-15) seconds) photo-induced switching from antiferromagnetic to ferromagnetic ordering in Pr0.7Ca0.3MnO3, by observing the establishment (within about 120 femtoseconds) of a huge temperature-dependent magnetization with photo-excitation threshold behaviour absent in the optical reflectivity. The development of ferromagnetic correlations during the femtosecond laser pulse reveals an initial quantum coherent regime of magnetism, distinguished from the picosecond (10(-12) seconds) lattice-heating regime characterized by phase separation without threshold behaviour. Our simulations reproduce the nonlinear femtosecond spin generation and underpin fast quantum spin-flip fluctuations correlated with coherent superpositions of electronic states to initiate local ferromagnetic correlations. These results merge two fields, femtosecond magnetism in metals and band insulators, and non-equilibrium phase transitions of strongly correlated electrons, in which local interactions exceeding the kinetic energy produce a complex balance of competing orders.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Li, Tianqi -- Patz, Aaron -- Mouchliadis, Leonidas -- Yan, Jiaqiang -- Lograsso, Thomas A -- Perakis, Ilias E -- Wang, Jigang -- England -- Nature. 2013 Apr 4;496(7443):69-73. doi: 10.1038/nature11934.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/23552945" target="_blank"〉PubMed〈/a〉
    Keywords: Biology ; Chemistry ; Circular Dichroism ; Electronics ; Iron/chemistry ; *Magnetic Phenomena ; Magnetics ; Optics and Photonics ; Photosynthesis ; *Quantum Theory ; Temperature ; Time Factors
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    Electronic ISSN: 1476-4687
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
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  • 6
    Publication Date: 2014-11-20
    Description: Flash memory devices--that is, non-volatile computer storage media that can be electrically erased and reprogrammed--are vital for portable electronics, but the scaling down of metal-oxide-semiconductor (MOS) flash memory to sizes of below ten nanometres per data cell presents challenges. Molecules have been proposed to replace MOS flash memory, but they suffer from low electrical conductivity, high resistance, low device yield, and finite thermal stability, limiting their integration into current MOS technologies. Although great advances have been made in the pursuit of molecule-based flash memory, there are a number of significant barriers to the realization of devices using conventional MOS technologies. Here we show that core-shell polyoxometalate (POM) molecules can act as candidate storage nodes for MOS flash memory. Realistic, industry-standard device simulations validate our approach at the nanometre scale, where the device performance is determined mainly by the number of molecules in the storage media and not by their position. To exploit the nature of the core-shell POM clusters, we show, at both the molecular and device level, that embedding [(Se(IV)O3)2](4-) as an oxidizable dopant in the cluster core allows the oxidation of the molecule to a [Se(v)2O6](2-) moiety containing a {Se(V)-Se(V)} bond (where curly brackets indicate a moiety, not a molecule) and reveals a new 5+ oxidation state for selenium. This new oxidation state can be observed at the device level, resulting in a new type of memory, which we call 'write-once-erase'. Taken together, these results show that POMs have the potential to be used as a realistic nanoscale flash memory. Also, the configuration of the doped POM core may lead to new types of electrical behaviour. This work suggests a route to the practical integration of configurable molecules in MOS technologies as the lithographic scales approach the molecular limit.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Busche, Christoph -- Vila-Nadal, Laia -- Yan, Jun -- Miras, Haralampos N -- Long, De-Liang -- Georgiev, Vihar P -- Asenov, Asen -- Pedersen, Rasmus H -- Gadegaard, Nikolaj -- Mirza, Muhammad M -- Paul, Douglas J -- Poblet, Josep M -- Cronin, Leroy -- England -- Nature. 2014 Nov 27;515(7528):545-9. doi: 10.1038/nature13951. Epub 2014 Nov 19.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉WestCHEM, School of Chemistry, The University of Glasgow, Glasgow G12 8QQ, UK. ; School of Engineering, The University of Glasgow, Glasgow G12 8LT, UK. ; Departament de Quimica Fisica i Inorganica, Universitat Rovira i Virgili, Marcel.li Domingo street, 43007 Tarragona, Spain.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/25409147" target="_blank"〉PubMed〈/a〉
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    Electronic ISSN: 1476-4687
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
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  • 7
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    American Association for the Advancement of Science (AAAS)
    In: Science
    Publication Date: 2018-08-10
    Description: The Hedgehog (Hh) pathway involved in development and regeneration is activated by the extracellular binding of Hh to the membrane receptor Patched (Ptch). We report the structures of human Ptch1 alone and in complex with the N-terminal domain of human Sonic hedgehog (ShhN) at resolutions of 3.9 and 3.6 angstroms, respectively, as determined by cryo–electron microscopy. Ptch1 comprises two interacting extracellular domains, ECD1 and ECD2, and 12 transmembrane segments (TMs), with TMs 2 to 6 constituting the sterol-sensing domain (SSD). Two steroid-shaped densities are resolved in both structures, one enclosed by ECD1/2 and the other in the membrane-facing cavity of the SSD. Structure-guided mutational analysis shows that interaction between ShhN and Ptch1 is steroid-dependent. The structure of a steroid binding–deficient Ptch1 mutant displays pronounced conformational rearrangements.
    Keywords: Biochemistry
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Geosciences , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 8
    Publication Date: 2018-11-28
    Description: A direct, catalytic conversion of benzene to phenol would have wide-reaching economic impacts. Fe zeolites exhibit a remarkable combination of high activity and selectivity in this conversion, leading to their past implementation at the pilot plant level. There were, however, issues related to catalyst deactivation for this process. Mechanistic insight...
    Print ISSN: 0027-8424
    Electronic ISSN: 1091-6490
    Topics: Biology , Medicine , Natural Sciences in General
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  • 9
    Publication Date: 2011-06-04
    Description: Type 1 pili are the archetypal representative of a widespread class of adhesive multisubunit fibres in Gram-negative bacteria. During pilus assembly, subunits dock as chaperone-bound complexes to an usher, which catalyses their polymerization and mediates pilus translocation across the outer membrane. Here we report the crystal structure of the full-length FimD usher bound to the FimC-FimH chaperone-adhesin complex and that of the unbound form of the FimD translocation domain. The FimD-FimC-FimH structure shows FimH inserted inside the FimD 24-stranded beta-barrel translocation channel. FimC-FimH is held in place through interactions with the two carboxy-terminal periplasmic domains of FimD, a binding mode confirmed in solution by electron paramagnetic resonance spectroscopy. To accommodate FimH, the usher plug domain is displaced from the barrel lumen to the periplasm, concomitant with a marked conformational change in the beta-barrel. The amino-terminal domain of FimD is observed in an ideal position to catalyse incorporation of a newly recruited chaperone-subunit complex. The FimD-FimC-FimH structure provides unique insights into the pilus subunit incorporation cycle, and captures the first view of a protein transporter in the act of secreting its cognate substrate.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3162478/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3162478/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Phan, Gilles -- Remaut, Han -- Wang, Tao -- Allen, William J -- Pirker, Katharina F -- Lebedev, Andrey -- Henderson, Nadine S -- Geibel, Sebastian -- Volkan, Ender -- Yan, Jun -- Kunze, Micha B A -- Pinkner, Jerome S -- Ford, Bradley -- Kay, Christopher W M -- Li, Huilin -- Hultgren, Scott J -- Thanassi, David G -- Waksman, Gabriel -- 29549/PHS HHS/ -- 48689/PHS HHS/ -- 49950/PHS HHS/ -- 85602/Medical Research Council/United Kingdom -- BB/F001134/1/Biotechnology and Biological Sciences Research Council/United Kingdom -- G0100442/Medical Research Council/United Kingdom -- G0100442(58149)/Medical Research Council/United Kingdom -- G0800002/Medical Research Council/United Kingdom -- GM62987/GM/NIGMS NIH HHS/ -- GM74985/GM/NIGMS NIH HHS/ -- P30 EB009998/EB/NIBIB NIH HHS/ -- R01 GM062987/GM/NIGMS NIH HHS/ -- England -- Nature. 2011 Jun 2;474(7349):49-53. doi: 10.1038/nature10109.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Institute of Structural and Molecular Biology, University College London and Birkbeck College, Malet Street, London WC1E 7HX, UK.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/21637253" target="_blank"〉PubMed〈/a〉
    Keywords: Adhesins, Escherichia coli/*chemistry/metabolism ; Crystallization ; Escherichia coli Proteins/*chemistry/metabolism ; Fimbriae Proteins/*chemistry/metabolism ; *Models, Molecular ; Protein Binding ; Protein Structure, Quaternary
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  • 10
    Publication Date: 2018-03-06
    Description: Objectives The study aimed to develop and validate a model to measure psychosocial factors at work among medical staff in China based on confirmatory factor analysis (CFA). The second aim of the current study was to clarify the association between stress-related psychosocial work factors and suboptimal health status. Design The cross-sectional study was conducted using clustered sampling method. Setting Xuanwu Hospital, a 3A grade hospital in Beijing. Participants Nine hundred and fourteen medical staff aged over 40 years were sampled. Seven hundred and ninety-seven valid questionnaires were collected and used for further analyses. The sample included 94% of the Han population. Main outcome measures The Copenhagen Psychosocial Questionnaire (COPSOQ) and the Suboptimal Health Status Questionnaires-25 were used to assess the psychosocial factors at work and suboptimal health status, respectively. CFA was conducted to establish the evaluating method of COPSOQ. A multivariate logistic regression model was used to estimate the relationship between suboptimal health status and stress-related psychosocial work factors among Chinese medical staff. Results There was a strong correlation among the five dimensions of COPSOQ based on the first-order factor model. Then, we established two second-order factors including negative and positive psychosocial work stress factors to evaluate psychosocial factors at work, and the second-order factor model fit well. The high score in negative (OR (95% CI)=1.47 (1.34 to 1.62), P〈0.001) and positive (OR (95% CI)=0.96 (0.94 to 0.98), P〈0.001) psychosocial work factors increased and decreased the risk of suboptimal health, respectively. This relationship remained statistically significant after adjusting for confounders and when using different cut-offs of suboptimal health status. Conclusions Among medical staff, the second-order factor model was a suitable method to evaluate the COPSOQ. The negative and positive psychosocial work stress factors might be the risk and protective factors of suboptimal health, respectively. Moreover, negative psychosocial work stress was the most associated factor to predict suboptimal health.
    Keywords: Open access, Mental health
    Electronic ISSN: 2044-6055
    Topics: Medicine
    Published by BMJ Publishing
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