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Structural Biology
Molecular mechanisms of cooperative binding of transcription factors Runx1-CBFβ-Ets1 on the TCRα gene enhancer
Feb 23, 2017   PloS One
Kasahara K, Shiina M, Fukuda I, Ogata K, Nakamura H
Molecular mechanisms of cooperative binding of transcription factors Runx1-CBFβ-Ets1 on the TCRα gene enhancer
Feb 23, 2017
PloS One
Ets1 is an essential transcription factor (TF) for several important physiological processes, including cell proliferation and differentiation. Its recognition of the enhancer region of the TCRα gene is enhanced by the cooperative binding of the Runx1-CBFβ heterodimer, with the cancelation of phosphorylation-dependent autoinhibition. The detailed mechanism of this interesting cooperativity between Ets1 and the Runx1-CBFβ heterodimer is still largely unclear. Here, we investigated the molecular mechanisms of this cooperativity, by using molecular dynamics simulations. Consequently, we detected high flexibility of the loop region between the HI2 and H1 helices of Ets1. Upon Runx1-CBFβ heterodimer binding, this loop transiently adopts various sub-stable conformations in its interactions with the DNA. In addition, a network analysis suggested an allosteric pathway in the molecular assembly and identified some key residues that coincide with previous experimental studies. Our simulations suggest that the cooperative binding of Ets1 and the Runx1-CBFβ heterodimer alters the DNA conformation and induces sub-stable conformations of the HI2-H1 loop of Ets1. This phenomenon increases the flexibility of the regulatory module, including the HI2 helix, and destabilizes the inhibitory form of this module. Thus, we hypothesize that this effect facilitates Ets1-DNA binding and prevents the phosphorylation-dependent DNA binding autoinhibition.
Molecular dynamics simulations reveal ligand-controlled positioning of a peripheral protein complex in membranes
Feb 24, 2017   Nature Communications
Ryckbosch SM, Wender PA, Pande VS
Molecular dynamics simulations reveal ligand-controlled positioning of a peripheral protein complex in membranes
Feb 24, 2017
Nature Communications
Bryostatin is in clinical trials for Alzheimer's disease, cancer, and HIV/AIDS eradication. It binds to protein kinase C competitively with diacylglycerol, the endogenous protein kinase C regulator, and plant-derived phorbol esters, but each ligand induces different activities. Determination of the structural origin for these differing activities by X-ray analysis has not succeeded due to difficulties in co-crystallizing protein kinase C with relevant ligands. More importantly, static, crystal-lattice bound complexes do not address the influence of the membrane on the structure and dynamics of membrane-associated proteins. To address this general problem, we performed long-timescale (400-500 µs aggregate) all-atom molecular dynamics simulations of protein kinase C-ligand-membrane complexes and observed that different protein kinase C activators differentially position the complex in the membrane due in part to their differing interactions with waters at the membrane inner leaf. These new findings enable new strategies for the design of simpler, more effective protein kinase C analogs and could also prove relevant to other peripheral protein complexes.Natural supplies of bryostatin, a compound in clinical trials for Alzheimer's disease, cancer, and HIV, are scarce. Here, the authors perform molecular dynamics simulations to understand how bryostatin interacts with membrane-bound protein kinase C, offering insights for the design of bryostatin analogs.
Original research paper. A superior preparation method for daidzein-hydroxypropyl-β-cyclodextrin complexes with improved solubility and dissolution: Supercritical fluid process
Feb 23, 2017   Acta Pharmaceutica (Zagreb, Croatia)
Pan H, Wang HB, Yu YB, Cheng BC, Wang XY, Li Y
Original research paper. A superior preparation method for daidzein-hydroxypropyl-β-cyclodextrin complexes with improved solubility and dissolution: Supercritical fluid process
Feb 23, 2017
Acta Pharmaceutica (Zagreb, Croatia)
Advantages of the supercritical fluid (SCF) process compared to the conventional solution stirring method (CSSM) in the preparation of daidzein-hydroxypropyl-β-cyclodextrin (HPβCD) complexes were investigated. Formation of daidzein/ HPβCD inclusion complexes was confirmed by Fourier transformed-infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), X-ray diffraction (XRD) and scanning electron microscopy (SEM). Particle size, inclusion yield, drug solubility and dissolution of daidzein/HPβCD complexes were evaluated. Compared to CSSM, the SCF process resulted in higher inclusion yield and higher solubility. Also, extended dissolution of daidzein from the SCF processed HPβCD inclusion complexes was observed, with only 22.94 % released in 45 min, compared to its rapid release from those prepared by CSSM, with 98.25 % drug release in 15 min. This extended release of daidzein from SCF prepared inclusion complexes was necessary to avoid drug precipitation and improve drug solubilisation in the gastrointestinal tract. The results showed that the SCF process is a superior preparation method for daidzein-hydroxypropyl-β-cyclodextrin complexes.
Crystal phases in hybrid metal-semiconductor nanowire devices
Feb 23, 2017   Nano Letters
David J, Rossella F, Rocci M, Ercolani D, Sorba L, Beltram F, Gemmi M, Roddaro S
Crystal phases in hybrid metal-semiconductor nanowire devices
Feb 23, 2017
Nano Letters
We investigate the metallic phases observed in hybrid metal-GaAs nanowire devices obtained by controlled thermal annealing of Ni/Au electrodes. Devices are fabricated onto a SiN membrane compatible with transmission electron microscopy studies. Energy dispersive X-ray spectroscopy allows us to show that the nanowire body includes two Ni-rich phases that, thanks to an innovative use of electron diffraction tomography, can be unambiguously identified as Ni
Chitosan-modified filter paper for nucleic acid extraction and "in situ PCR" on a thermoplastic microchip
Feb 23, 2017   Analytical Chemistry
Gan W, Gu Y, Han J, Li C, Sun J, Liu P
Chitosan-modified filter paper for nucleic acid extraction and "in situ PCR" on a thermoplastic microchip
Feb 23, 2017
Analytical Chemistry
Plastic microfluidic devices with embedded chitosan-modified Fusion 5 filter paper (unmodified one purchased from GE Healthcare) have been successfully developed for DNA extraction and concentration, utilizing two different mechanisms for DNA capture: the physical entanglement of long-chain DNA molecules with the fiber matrix of the filter paper and the electrostatic adsorption of DNA to the chitosan-modified filter fibers. This new method not only provided a high DNA extraction efficiency at a pH of 5 by synergistically combining these two capture mechanisms together, but also resisted the elution of DNA from filters at a pH >8 due to the entanglement of DNA with fibers. As a result, PCR buffers can be directly loaded into the extraction chamber for "in situ PCR", in which the captured DNA were used for downstream analysis without any loss. We demonstrated that the capture efficiencies of a 3-mm-diameter filter disc in a microchip were 98% and 95% for K562 human genomic DNA and bacteriophage λ-DNA, respectively. The washes with DI water, PCR mixture, and TE buffer cannot elute the captured DNA. In addition, the filter disc can enrich 62% of λ-DNA from a diluted sample (0.05 ng/μL), providing a concentration factor more than 30 fold. Finally, a microdevice with a simple two-chamber structure was developed for on-chip cell lysis, DNA extraction, and 15-plex short tandem repeat amplification from blood. This DNA extraction coupled with "in situ PCR" has great potential to be utilized in fully integrated microsystems for rapid, near-patient nucleic acid testing.
Feb 24, 2017   Frontiers In Pharmacology
Bi MJ, Sun XN, Zou Y, Ding XY, Liu B, Zhang YH, Guo DD, Li Q
Feb 24, 2017
Frontiers In Pharmacology
Cognitive impairment is the most common neurologic sequelae after carbon monoxide (CO) poisoning, and the previous investigations have demonstrated that
Hydrophilicities of amylose and natural cellulose are regulated by the linkage between sugar rings
Feb 24, 2017   Nanoscale
Bao Y, Xu D, Qian L, Zhao L, Lu ZY, Cui S
Hydrophilicities of amylose and natural cellulose are regulated by the linkage between sugar rings
Feb 24, 2017
Nanoscale
Comparative studies of single molecule force spectroscopy and molecular dynamics simulations indicate that natural cellulose is more hydrophobic than amylose at the single-chain level, implying that the hydrophobicities of these polymeric isomers are regulated by only one parameter in the chains, the linkage between the sugar rings.
PEGylated graphene oxide elicits strong immunological responses despite surface passivation
Feb 24, 2017   Nature Communications
Luo N, Weber JK, Wang S, Luan B, Yue H, Xi X, Du J, Yang Z, Wei W, Zhou R, Ma G
PEGylated graphene oxide elicits strong immunological responses despite surface passivation
Feb 24, 2017
Nature Communications
Engineered nanomaterials promise to transform medicine at the bio-nano interface. However, it is important to elucidate how synthetic nanomaterials interact with critical biological systems before such products can be safely utilized in humans. Past evidence suggests that polyethylene glycol-functionalized (PEGylated) nanomaterials are largely biocompatible and elicit less dramatic immune responses than their pristine counterparts. We here report results that contradict these findings. We find that PEGylated graphene oxide nanosheets (nGO-PEGs) stimulate potent cytokine responses in peritoneal macrophages, despite not being internalized. Atomistic molecular dynamics simulations support a mechanism by which nGO-PEGs preferentially adsorb onto and/or partially insert into cell membranes, thereby amplifying interactions with stimulatory surface receptors. Further experiments demonstrate that nGO-PEG indeed provokes cytokine secretion by enhancing integrin β
Recombinant Wheat Endoplasmic Reticulum Oxidoreductin 1 Improved Wheat Dough Properties and Bread Quality
Feb 24, 2017   Journal Of Agricultural And Food Chemistry
Liu G, Wang J, Hou Y, Huang Y, Zhang YP, Li CZ, Li L, Hu SQ
Recombinant Wheat Endoplasmic Reticulum Oxidoreductin 1 Improved Wheat Dough Properties and Bread Quality
Feb 24, 2017
Journal Of Agricultural And Food Chemistry
Recombinant wheat endoplasmic reticulum oxidoreductin 1 (wEro1) with considerable ability was expressed in E. coli. The functional roles of wEro1 in flour processing quality were investigated by farinographic, rheological and texture profile analysis, electrophoresis, size exclusion chromatography, scanning electron microscopy and Fourier transform infrared spectroscopy. wEro1 exhibited an obvious oxidation activity of sulfydryl groups in small molecule and protein. Addition of wEro1 could strengthen the processing quality of dough, indicated by the improved mixing characteristics, viscoelastic properties and bread qualities. These improvement effects of wEro1 could be attributed to the formation of macro-molecular gluten polymers and massive gluten network by disulfide cross-linking. Additionally, the increased β-turn structure further demonstrated the enhancement of dough strength. Moreover, the amount of peroxide in dough was improved significantly from 2.36 to 2.82 μmol/g of flour with 0.15% wEro1 treatment. Therefore, the results suggested that wEro1 was promised to be a novel flour improver.
Histology and ultrastructure of the thymus during development in tilapia, Oreochromis niloticus
Feb 24, 2017   Journal Of Anatomy
Cao J, Chen Q, Lu M, Hu X, Wang M
Histology and ultrastructure of the thymus during development in tilapia, Oreochromis niloticus
Feb 24, 2017
Journal Of Anatomy
The thymus in teleost fishes plays an important role in producing functionally competent T-lymphocytes. However, the thymus in tilapia is not well known, which greatly hampers investigations into the immune responses of tilapia infected by aquatic pathogens. The histological structure and ultrastructure of the thymus in Oreochromis niloticus, including embryos and larvae at different developmental stages, juveniles, and adult fish, were systematically investigated using whole mount in situ hybridization (WISH), and light and transmission electron microscopy (TEM). The position of the thymus primordium was first labeled in the embryo at 2 days post-fertilization (dpf) with the thymus marker gene recombination activating gene 1 (Rag1), when the water temperature was 27 °C. Obvious structures of the thymus were easily observed in 4-dpf embryos. At this stage, the thymus was filled with stem cells. At 6 dpf, the thymus differentiated into the cortex and medulla. The shape of the thymus was 'broad bean'-like during the early stages from 4 to 10 dpf, and became wedge-shaped in fish larvae at 20 dpf. At 6 months post-fertilization (mpf), the thymus differentiated into the peripheral zone, central zone, and inner zone. During this stage, myoid cells and adipocytes appeared in the inner zone following thymus degeneration. Then, the thymus displayed more advanced degeneration by 1 year post-fertilization (ypf), and the separation of cortex and medulla was not observed at this stage. The thymic trabecula and lobule were absent during the entire course of development. However, the typical Hassall's corpuscle was present and underwent degeneration. Additionally, TEM showed that the thymic tissues contained a wide variety of cell types, namely lymphocytes, macrophages, epithelial cells, fibroblasts, and mastocytes.© 2017 Anatomical Society.
Research on magnetic separation for complex nickel deep removal and magnetic seed recycling
Feb 24, 2017   Environmental Science And Pollution Research International
Qiu Y, Xiao X, Ye Z, Guan Z, Sun S, Ren J, Yan P
Research on magnetic separation for complex nickel deep removal and magnetic seed recycling
Feb 24, 2017
Environmental Science And Pollution Research International
This study investigated the deep removal of complex nickel from simulated wastewater using magnetic separation and magnetic seed recycling. Nano-magnetite (Fe
Anatase (101)-like Structural Model Revealed for Metastable Rutile TiO2(011) Surface
Feb 23, 2017   ACS Applied Materials & Interfaces
Xu M, Shao S, Gao B, Lv J, Li Q, Wang Y, Wang H, Zhang L, Ma Y
Anatase (101)-like Structural Model Revealed for Metastable Rutile TiO2(011) Surface
Feb 23, 2017
ACS Applied Materials & Interfaces
Titanium dioxide has been widely used as efficient transition metal oxide photocatalyst. However, its photocatalytic activity is limited to ultraviolet spectrum range due to the deficient large bandgap beyond 3 eV. Efforts towards to reduce the bandgap for achieving a broader spectrum range of light absorption are attempted with a success on the experimental synthesis of dopant-free metastable surface structure of rutile-type TiO2 (011) 21. This new surface phase possesses a much reduced bandgap of ~2.1 eV, showing a great potential for an excellent photocatalyst covering a wide range of visible light. There is an urge to establish the atomistic structure of this metastable surface for understanding the physical cause for the bandgap reduction and for future design of better photocatalyst. We here report the computational investigations in an effort to unravel this surface structure via swarm structure-searching simulations. The established structure adopts the anatase (101)-like structure model, where the topmost two-fold O atoms form a quasi-hexagonal surface pattern, and bonded with unsaturated five-fold and four-fold Ti atoms in the next layer. The predicted anatase (101)-like surface model can naturally explain the experimental observation of STM image, the electronic bandgap, and the oxidation state of Ti4+. Dangling bonds on the anatase (101)-like surface are rich, making it a superior photocatalyst. First-principles molecular dynamics simulations has approved the high photocatalystic activity by showing that water and formic acid molecules dissociate spontaneously on this anatase (101)-like surface.
Oridonin induces autophagy via inhibition of glucose metabolism in p53-mutated colorectal cancer cells
Feb 23, 2017   Cell Death & Disease
Yao Z, Xie F, Li M, Liang Z, Xu W, Yang J, Liu C, Li H, Zhou H, Qu LH
Oridonin induces autophagy via inhibition of glucose metabolism in p53-mutated colorectal cancer cells
Feb 23, 2017
Cell Death & Disease
The Warburg effect is an important characteristic of tumor cells, making it an attractive therapeutic target. Current anticancer drug development strategies predominantly focus on inhibitors of the specific molecular effectors involved in tumor cell proliferation. These drugs or natural compounds, many of which target the Warburg effect and the underlying mechanisms, still need to be characterized. To elucidate the anticancer effects of a natural diterpenoid, oridonin, we first demonstrated the anticancer activity of oridonin both in vitro and in vivo in colorectal cancer (CRC) cells. Then miRNA profiling of SW480 cells revealed those intracellular signaling related to energy supply was affected by oridonin, suggesting that glucose metabolism is a potential target for CRC therapy. Moreover, our results indicated that oridonin induced metabolic imbalances by significantly inhibiting glucose uptake and reducing lactate export through significantly downregulating the protein levels of GLUT1 and MCT1 in vitro and vivo. However, the ATP level in oridonin-treated CRC cells was not decreased when oridonin blocked the glucose supply, indicating that oridonin induced autophagy process, an important ATP source in cancer cells. The observation was then supported by the results of LC3-II detection and transmission electron microscopy analysis, which confirmed the presence of autophagy. Furthermore, p-AMPK was rapidly deactivated following oridonin treatment, resulting in downregulation of GLUT1 and induction of autophagy in the cancer cells. Thus our finding helped to clarify the anticancer mechanisms of oridonin and suggested it could be applied as a glucose metabolism-targeting agent for cancer treatment.
Chlorhexidine-loaded amorphous calcium phosphate nanoparticles for inhibiting degradation and inducing mineralization of type I collagen
Feb 23, 2017   ACS Applied Materials & Interfaces
Cai X, Han B, Liu Y, Tian F, Liang F, Wang X
Chlorhexidine-loaded amorphous calcium phosphate nanoparticles for inhibiting degradation and inducing mineralization of type I collagen
Feb 23, 2017
ACS Applied Materials & Interfaces
A major shortcoming of contemporary dentin adhesives is their limited durability. Exposed collagen fibrils within the bonding interface are degraded by matrix metalloproteinases (MMPs), resulting in aging of the resin-dentin bond. In this study, chlorhexidine-loaded amorphous calcium phosphate (ACP) nanoparticles were synthesized to induce the mineralization of collagen fibrils. The nanoparticles sustainably released chlorhexidine, to inhibit MMPs during mineralization. Three types of ACP nanoparticles were prepared: N-ACP containing no chlorhexidine, C-ACP containing chlorhexidine acetate, and G-ACP containing chlorhexidine gluconate, which had a higher drug-loading than C-ACP. Scanning and transmission electron microscopy indicated that the synthesized nanoparticles had diameters of less than 100 nm. Some had diameters of less than 40 nm, which was smaller than the width of gap zones in the collagen fibrils. Energy dispersive X-ray spectroscopy, Fourier-transform infrared spectroscopy, and high performance liquid chromatography confirmed the presence of chlorhexidine in the nanoparticles. X-ray diffraction confirmed that the nanoparticles were amorphous. The drug loading was 0.11% for C-ACP and 0.53% for G-ACP. In vitro release profiles indicated that chlorhexidine was released sustainably via first-order kinetics. Released chlorhexidine inhibited the degradation of collagen in human dentine powder, and its effect lasted longer than that of pure chlorhexidine of the same concentration. The ACP could induce the mineralization of self-assembled type I collagen fibrils. The chlorhexidine-loaded ACP nanoparticles sustainably released chlorhexidine and ACP, under appropriate conditions. This is useful for inhibiting degradation and inducing the mineralization of dentine collagen fibrils.
An expanded genetic code for probing the role of electrostatics in enzyme catalysis by vibrational Stark spectroscopy
Feb 23, 2017   Biochimica Et Biophysica Acta
Völler JS, Biava H, Hildebrandt P, Budisa N
An expanded genetic code for probing the role of electrostatics in enzyme catalysis by vibrational Stark spectroscopy
Feb 23, 2017
Biochimica Et Biophysica Acta
BACKGROUND: To find experimental validation for electrostatic interactions essential for catalytic reactions represents a challenge due to practical limitations in assessing electric fields within protein structures. SCOPE OF REVIEW: This review examines the applications of non-canonical amino acids (ncAAs) as genetically encoded probes for studying the role of electrostatic interactions in enzyme catalysis. MAJOR CONCLUSIONS: ncAAs constitute sensitive spectroscopic probes to detect local electric fields by exploiting the vibrational Stark effect (VSE) and thus have the potential to map the protein electrostatics. GENERAL SIGNIFICANCE: Mapping the electrostatics in proteins will improve our understanding of natural catalytic processes and, in beyond, will be helpful for biocatalyst engineering. This article is part of a Special Issue entitled "Biochemistry of Synthetic Biology - Recent Developments" Guest Editor: Dr. Ilka Heinemann and Dr. Patrick O'Donoghue. Copyright © 2017. Published by Elsevier B.V.
A Helical Bundle in the N-terminal Domain of the BLM Helicase Mediates Dimer and Potentially Hexamer Formation
Feb 23, 2017   The Journal Of Biological Chemistry
Shi J, Chen WF, Zhang B, Fan SH, Ai X, Liu NN, Rety S, Xi XG
A Helical Bundle in the N-terminal Domain of the BLM Helicase Mediates Dimer and Potentially Hexamer Formation
Feb 23, 2017
The Journal Of Biological Chemistry
Helicases play a critical role in processes such as replication or recombination by unwinding double-stranded DNA; mutations of these genes can therefore have devastating biological consequences. In human, mutations in genes of three members of the RecQ family helicases (Copyright © 2017, The American Society for Biochemistry and Molecular Biology.
A Second Amorphous Layer Underneath Surface Oxide
Feb 23, 2017   Microscopy And Microanalysis : The Official Journal Of Microscopy Society Of America, Microbeam Analysis Society, Microscopical Society Of Canada
Zhang B, Peng K, Sha X, Li A, Zhou X, Chen Y, Deng Q, Yang D, Ma E, Han X
A Second Amorphous Layer Underneath Surface Oxide
Feb 23, 2017
Microscopy And Microanalysis : The Official Journal Of Microscopy Society Of America, Microbeam Analysis Society, Microscopical Society Of Canada
Formation of a nanometer-scale oxide surface layer is common when a material is exposed to oxygen-containing environment. Employing aberration-corrected analytical transmission electron microscopy and using single crystal SnSe as an example, we show that for an alloy, a second thin amorphous layer can appear underneath the outmost oxide layer. This inner amorphous layer is not oxide based, but instead originates from solid-state amorphization of the base alloy when its free energy rises to above that of the metastable amorphous state; which is a result of the composition shift due to the preferential depletion of the oxidizing species, in our case, the outgoing Sn reacting with the oxygen atmosphere.
Bayesian deconvolution of scanning electron microscopy images using point-spread function estimation and non-local regularization
Feb 23, 2017   Conference Proceedings : ... Annual International Conference Of The IEEE Engineering In Medicine And Biology Society. IEEE Engineering In Medicine And Biology Society. Annual Conference
Roels J, Aelterman J, De Vylder J, Luong H, Saeys Y,   . . . . . .   , Philips W, Aelterman J, De Vylder J, Saeys Y, Roels J
Bayesian deconvolution of scanning electron microscopy images using point-spread function estimation and non-local regularization
Feb 23, 2017
Conference Proceedings : ... Annual International Conference Of The IEEE Engineering In Medicine And Biology Society. IEEE Engineering In Medicine And Biology Society. Annual Conference
UNASSIGNED: Microscopy is one of the most essential imaging techniques in life sciences. High-quality images are required in order to solve (potentially life-saving) biomedical research problems. Many microscopy techniques do not achieve sufficient resolution for these purposes, being limited by physical diffraction and hardware deficiencies. Electron microscopy addresses optical diffraction by measuring emitted or transmitted electrons instead of photons, yielding nanometer resolution. Despite pushing back the diffraction limit, blur should still be taken into account because of practical hardware imperfections and remaining electron diffraction. Deconvolution algorithms can remove some of the blur in post-processing but they depend on knowledge of the point-spread function (PSF) and should accurately regularize noise. Any errors in the estimated PSF or noise model will reduce their effectiveness. This paper proposes a new procedure to estimate the lateral component of the point spread function of a 3D scanning electron microscope more accurately. We also propose a Bayesian maximum a posteriori deconvolution algorithm with a non-local image prior which employs this PSF estimate and previously developed noise statistics. We demonstrate visual quality improvements and show that applying our method improves the quality of subsequent segmentation steps.
Direct observation of intrinsic twin domains in tetragonal CH
Feb 23, 2017   Nature Communications
Rothmann MU, Li W, Zhu Y, Bach U, Spiccia L, Etheridge J, Cheng YB
Direct observation of intrinsic twin domains in tetragonal CH
Feb 23, 2017
Nature Communications
Organic-inorganic hybrid perovskites are exciting candidates for next-generation solar cells, with CH
Simultaneously enhanced efficiency and stability of polymer solar cells by employing solvent additive and upside-down drying method
Feb 23, 2017   ACS Applied Materials & Interfaces
Sun Q, Zhang F, An Q, Zhang M, Ma X, Zhang J
Simultaneously enhanced efficiency and stability of polymer solar cells by employing solvent additive and upside-down drying method
Feb 23, 2017
ACS Applied Materials & Interfaces
The morphology of active layer plays an important role in determining the power conversion efficiency (PCE) and stability of polymer solar cells (PSCs), which strongly depends on the dynamic drying process of active layer. In this work, an efficient and universal method was developed to let active layer undergo upside-down drying process in a covered glass petri dish. For the PSCs based on PTB7-Th:PC71BM, the champion PCEs were improved from 8.58% to 9.64% by mixing 3 vol% DIO, further to 10.30% by employing upside-down drying method. The enhanced PCEs of PSCs with active layer undergoing upside-down drying process are mainly attributed to the optimized vertical phase separation, the more ordered and tightly packed π-π stacking of polymer molecules. Meanwhile, PC71BM molecules can be frozen in more ordered and tightly packed π-π stacking polymer network, leading to the enhanced stability of PSCs. The universality of upside-down drying method can be solidly confirmed from PSCs with PTB7:PC71BM, PffBT4T-2OD:PC71BM or PBDT-TS1:PC71BM as active layers, respectively. The molecular packing and phase separation of blend films with different solvent additives and drying methods were investigated by grazing incidence X-ray diffraction (GIXD), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS).
Stabilized HIV-1 envelope glycoprotein trimers for vaccine use
Feb 23, 2017   Current Opinion In HIV And AIDS
Medina-Ramírez M, Sanders RW, Sattentau QJ
Stabilized HIV-1 envelope glycoprotein trimers for vaccine use
Feb 23, 2017
Current Opinion In HIV And AIDS
PURPOSE OF REVIEW: To provide an update on the latest developments in the field of HIV-1 antibody-based soluble envelope glycoprotein (Env) trimer design for vaccine use. RECENT FINDINGS: The development of soluble native-like HIV-1 Env trimer immunogens has moved the field of antibody-based vaccine design forward dramatically over the past few years with refinement of various stabilizing approaches. However, despite this progress, significant challenges remain. Firstly, although trimers are relatively stable in solution, they nevertheless sample different conformational states, some of which may be less relevant to binding and induction of broadly neutralizing antibodies (bNAbs). Secondly, these trimers expose unwanted immunodominant surfaces that may distract the adaptive immune response from recognizing more immunorecessive but conserved neutralization-relevant surfaces on the trimer. The availability of atomic-resolution structural information has allowed guided design of mutations that have further stabilized trimers and allowed reduced exposure of unwanted epitopes. Moreover, chemical cross-linking approaches that do not require structural information have also contributed to trimer stabilization and selection of particular conformational forms. However, current knowledge suggests that strategies additional to trimer stabilization will be required to elicit bNAb, including targeting naïve B cell receptors with specific immunogens, and guiding B cell lineages toward recognizing conserved surfaces on Env with high affinity. SUMMARY: This review will give a perspective on these challenges, and summarize current approaches to overcoming them with the aim of developing immunogens to elicit bNAb responses in humans by active vaccination.This is an open access article distributed under the Creative Commons Attribution License 4.0 (CCBY), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. http://creativecommons.org/licenses/by/4.0.
Phloem unloading in Arabidopsis roots is convective and regulated by the phloem-pole pericycle
Feb 23, 2017   ELife
Ross-Elliott TJ, Jensen KH, Haaning KS, Wager BM, Knoblauch J,   . . . . . .   , Sager R, Lee JY, Helariutta Y, Knoblauch M, Oparka KJ
Phloem unloading in Arabidopsis roots is convective and regulated by the phloem-pole pericycle
Feb 23, 2017
ELife
In plants, a complex mixture of solutes and macromolecules is transported by the phloem. Here we examined how solutes and macromolecules are separated when they exit the phloem during the unloading process. We used a combination of approaches (non-invasive imaging, 3D-electron microscopy, and mathematical modelling) to show that phloem unloading of solutes in Arabidopsis roots occurs through plasmodesmata by a combination of mass flow and diffusion (convective phloem unloading). During unloading, solutes and proteins are diverted into the phloem-pole pericycle, a tissue connected to the protophloem by a unique class of 'funnel plasmodesmata'. While solutes are unloaded without restriction, large proteins are released through funnel plasmodesmata in discrete pulses, a phenomenon we refer to as 'batch unloading'. Unlike solutes, these proteins remain restricted to the phloem-pole pericycle. Our data demonstrate a major role for the phloem-pole pericycle in regulating phloem unloading in roots.
Facet-Dependent Thermal Instability in LiCoO2
Feb 23, 2017   Nano Letters
Sharifi-Asl S, Soto FA, Nie A, Yuan Y, Asayesh-Ardakani H, Foroozan T, Yurkiv V, Song B, Mashayek F, Klie RF, Amine K, Lu J, Balbuena PB, Shahbazian-Yassar R
Facet-Dependent Thermal Instability in LiCoO2
Feb 23, 2017
Nano Letters
Thermal runaways triggered by the oxygen release from oxide cathode materials pose a major safety concern for widespread application of lithium ion batteries. Utilizing in-situ aberration-corrected scanning transmission electron microscopy (STEM) and electron energy loss spectroscopy (EELS) at high temperatures, we show that oxygen release from LixCoO2 cathode crystals is occurring at the surface of particles. We correlated this local oxygen evolution from the LixCoO2 structure with local phase transitions spanning from layered to spinel and then to rock salt structure upon exposure to elevated temperatures. Ab initio molecular dynamics simulations (AIMD) results show that oxygen release is highly dependent on LixCoO2 facet orientation. While the [001] facets are stable at 300 °C, oxygen release is observed from the [012] and [104] facets, where under-coordinated oxygen atoms from the delithiated structures can combine and eventually evolve as O2. The novel understanding that emerges from the present study provides in-depth insights into the thermal runaway mechanism of Li-ion batteries and can assist the design and fabrication of cathode crystals with the most thermally stable facets.
Inhibition and Stabilization: Cucurbituril Induced Distinct Effects on the Schiff Base Reaction
Feb 23, 2017   The Journal Of Organic Chemistry
Gong W, Ma J, Zhao Z, Gao F, Liang F, Zhang H, Liu S
Inhibition and Stabilization: Cucurbituril Induced Distinct Effects on the Schiff Base Reaction
Feb 23, 2017
The Journal Of Organic Chemistry
The different effects of cucurbit[7]uril (CB[7]) on the Schiff base reactions in aqueous solution were explored by 1H NMR spectroscopy and single X-ray crystallography. With CB[7] the condensation reaction of aldehyde and primary amine is dramatically inhibited. In contrast the presence of CB[7] does tremendously stabilize iminium cation in water through ion-dipole interactions. A single crystal structure of the complex of iminium ion 7 with CB[7] grown in water is reported.
The anesthetic agent sevoflurane attenuates pulmonary acute lung injury by modulating apoptotic pathways
Feb 22, 2017   Brazilian Journal Of Medical And Biological Research = Revista Brasileira De Pesquisas Medicas E Biologicas
Wang L, Ye Y, Su HB, Yang JP
The anesthetic agent sevoflurane attenuates pulmonary acute lung injury by modulating apoptotic pathways
Feb 22, 2017
Brazilian Journal Of Medical And Biological Research = Revista Brasileira De Pesquisas Medicas E Biologicas
UNASSIGNED: The objective of this study was to evaluate lung protection by the volatile anesthetic sevoflurane (SEVO), which inhibits apoptosis. Male Sprague-Dawley rats (250-280 g; n=18) were randomly divided into three groups. The LPS group received 5 mg/kg endotoxin (lipopolysaccharide), which induced acute lung injury (ALI). The control (CTRL) group received normal saline and the SEVO group received sevoflurane (2.5%) for 30 min after ALI was induced by 5 mg/kg LPS. Samples were collected for analysis 12 h after LPS. Lung injury was assessed by pathological observations and tissue wet to dry weight (W/D) ratios. Apoptotic index (AI) was determined by terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) assay and electron microscopy. Caspase-3 and cleaved-caspase-3 protein levels were determined by immunocytochemistry and western blotting, respectively. Bcl-xl levels were measured by western blotting and Bcl-2 levels by quantitative real-time polymerase chain reaction and western blotting. In the LPS group, W/D ratios, AI values, caspase-3 and cleaved-caspase-3 levels were significantly higher than in the CTRL group and lung injury was more severe. In the SEVO group, W/D ratios, AI, caspase-3 and cleaved-caspase-3 were lower than in the LPS group. Bcl-2 and Bcl-xl expression were higher than in the LPS group and lung injury was attenuated. Sevoflurane inhalation protected the lungs from injury by regulating caspase-3 activation and Bcl-xl and Bcl-2 expression to inhibit excessive cell apoptosis, and such apoptosis might be important in the pathogenesis of LPS-induced ALI.

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