Effect of Na-ion intercalation on the thermal conductivity of carbon honeycomb nanostructure.

This work studies the thermal conductivity of Na-ion intercalated carbon honeycomb (CHC) via the combination of first-principles calculation and molecular dynamics simulation. The effects of ion concentration, ion charge, temperature, and strain are explored. The simulation results show that the thermal conductivity of CHC presents a nonmonotonic dependence on the ion concentration. The enhanced phonon scattering and increased phonon group velocities of CHC induced by its interaction with the Na ions are responsible for the nonmonotonic dependence. Both the increases in the ion charge and temperature reduce the thermal conductivity. In contrast, a compressive strain of around -3% can increase the thermal conductivity by eliminating the phonon softening effect caused by the volume expansion of CHC during the ion intercalation. However, further increasing the strain negatively or positively from -3% leads to a decrease in the thermal conductivity. The simulation results presented in this work are beneficial in understanding the thermal properties of CHC when it is used as an electrode in ion batteries and supercapacitors.

Impact of team knowledge management, problem solving competence, interpersonal conflicts, organizational trust on project performance, a mediating role of psychological capital.

There has been substantial research on megaprojects in project management literature. However, there is dearth of studies empirically investigating performance of new launched megaproject of Thailand that named as "Phuket sandbox". The core purpose of this project is to normalize covid-19 situation and resuming tourism in Thailand. Therefore, the evaluation of project performance is essential to achieve the targeted goal for success. The purpose of this study is to investigate the factors that affect project performance (Phuket sandbox) in Thailand. This study used quantitative approach based on structured questionnaire and the data was collected from Phuket, Thailand. The survey conducted from team members which are tourism stake holders' team, immigration team and public service teams including hospitals and hotels who were supposed for the management of Phuket tourism sandbox operations. The study got 222 valid responses only as the members were so busy and partial lockdowns in Thailand hindered the data collection process. The proposed hypothetical model tested by partial least square structural equation modelling. The results of the study found mix findings. The independent variables are team knowledge management, interpersonal conflict, organizational trust, and as significant and dependent variable as project performance through the mediation of psychological capital. The all relationships found to be significant except problem solving competence which have insignificant relationship with project performance as well as problem solving competence and organizational trust have insignificant relation with psychological capital.

Research progress in prediction of postpartum depression. / äº§åŽæŠ‘éƒé¢„æµ‹ç ”ç©¶è¿›å±•.

Postpartum depression is a kind of mental disorder caused by the comprehensive effects of economics, psychosociology, biology, obstetrics and other characteristic factors in the process of female pregnancy. The pathogenesis of postpartum depression is complicated and has not been clarified. With the process pregnancy, the influence of psychosocial and biology factors are also in dynamic change. The postpartum depression predictor among psychosocial factors are antenatal depression, life events and social supports. Among biological factors, the predictors are hypothalamic-pituitary-thyroid axis and serum lipids. Timely and effective prediction can identify the high-risk population and risk factors for postpartum depression.

Cryo-EM structure of native spherical subviral particles isolated from HBV carriers.

Hepatitis B virus (HBV) contains 3 types of particles, i.e., 22-nm-diameter spherical and tubular subviral particles (SVPs) and 44-nm-diameter Dane particles. The SVPs are non-infectious and present strong immunogenicity, while Dane particles are infectious. In this study, we isolated spherical SVPs from HBV carriers' sera and determined their 3D structure at the resolution of ∼30 Šby cryo-electron microscopy (cryo-EM) single-particle reconstruction. Our cryo-EM structure suggests that the native HBV spherical SVP is irregularly organized, where spike-like features are arranged in a crystalline-like pattern on the surface. Strikingly, the hepatitis B surface antigen (HBsAg) in the native spherical SVPs folds as protrusions on the surface, as those on the native tubular SVPs and Dane particles, but is largely different from that in the recombinant octahedral SVPs. These results suggest a universal folding shape of HBsAg on the native HBV viral and subviral particles.

Structure determination of a human virus by the combination of cryo-EM and X-ray crystallography.

Virus 3D atomic structures provide insight into our understanding of viral life cycles and the development of antiviral drugs. X-ray crystallography and cryo-EM have been used to determine the atomic structure of viruses. However, limited availability of biological samples, biosafety issues due to virus infection, and sometimes inherent characteristics of viruses, pose difficulties on combining both methods in determining viral structures. These have made solving the high resolution structure of some medically important viruses very challenging. Here, we describe our recently employed protocols for determining the high-resolution structure of the virus-like particle of hepatitis E virus (HEV), a pathogen of viral hepatitis in human. These protocols include utilizing recombinant baculovirus system to generate sufficient amount of virus particles, single-particle cryo-EM to get an intermediate resolution structure as a phasing model, and X-ray crystallography for final atomic structure determination. Our protocols have solved the hepatitis E virus structure to the resolution of 3.5 Å. The combined methodology is generally applicable to other human infectious viruses.

Hydrophobic coating of polyaniline-poly(propylene oxide) copolymer for direct immersion solid phase microextraction of carbamate pesticides.

A nanostructural polyaniline-poly(propylene oxide) (PANI-PPO) composite coating was electrochemically synthesized on a stainless steel wire, by using acidic ionic liquid 1-sulfobutyl-3-methylimidazolium hydrosulfate as supporting electrolyte. The coating showed strong hydrophobicity and allowed for the direct immersion solid-phase microextraction of carbamate pesticides (i.e. 2-(1-methylethoxy) phenyl methylcarbamate, m-tolyl-n-methylcarbamate, 2-(1-methylethyl) phenyl methylcarbamate, 2-(1-methylpropyl) phenol methylcarbamate and 2,3-dihydro-2,2-dimethyl-7-benzofuranyl methylcarbamate) in complex matrices. Moreover, this coating could be used for at least 120 times of extraction. When it was coupled with gas chromatography for the determination of these carbamate pesticides the linear ranges were about 0.1-100 µg L(-1) and the detection limits were 0.012-0.048 µg L(-1). It also displayed acceptable repeatability and reproducibility. When a fiber was used for five successive measurements the relative standard deviations (RSDs) were smaller than 8.7%, and the RSDs for fiber-to-fiber were 5.7-12.9% (n=5). The practical feasibility of the proposed method was evaluated by determining carbamate pesticides in vegetable samples and the recoveries for standards added were 79.8-108.8%.

[Psychometric features of the body image after breast cancer questionnaire-Chinese version in women with breast cancer].

OBJECTIVE: To examine the psychometric features of the body image after breast cancer questionnaire-Chinese version (BIBCQ-C) in Chinese women with breast cancer. METHODS: A total of 545 women with breast cancer received a demographics investigation: BIBCQ-C and hospital anxiety and depression scale (HAD). Four weeks later, 31 patients were selected randomly to finish BIBCQ-C again. RESULTS: The Cronbach's alpha coefficient for the total scale was 0.90, and that for the 6 factors ranged from 0.62 to 0.87. The mean inter-item correlation coefficient of the total scale was 0.16, and the mean inter-item correlation coefficient of the subscales ranged from 0.21 to 0.57, and the test-retest reliability of the total scale and 6 factors was over 0.60. The confirmatory factor analyses supported the 6-factor model, and BIBCQ-C were significantly correlated with the symptom scales of anxiety and depression (r=0.20, 0.21, P<0.01). CONCLUSION: BIBCQ-C is reliable and valid, which can effectively assess body image of Chinese women with breast cancer.

Transmission electron microscopy studies of cellular responses to entry of virions: one kind of natural nanobiomaterial.

Virions are one kind of nanoscale pathogen and are able to infect living cells of animals, plants, and bacteria. The infection is an intrinsic property of the virions, and the biological process provides a good model for studying how these nanoparticles enter into cells. During the infection, the viruses employ different strategies to which the cells have developed respective responses. For this paper, we chose Bombyx mori cypovirus 1 (BmCPV-1) interactions with midgut cells from silkworm, and severe acute respiratory syndrome (SARS) associated coronavirus interactions with Vero E6 cells, as examples to demonstrate the response of eukaryotic cells to two different types of virus from our previous studies. The bacteriophage-bacteria interactions are also introduced to elucidate how the bacteriophage conquers the barrier of cell walls in the prokaryotic cells to transport genome into the host.

Atomic model of a cypovirus built from cryo-EM structure provides insight into the mechanism of mRNA capping.

The cytoplasmic polyhedrosis virus (CPV) from the family Reoviridae belongs to a subgroup of "turreted" reoviruses, in which the mRNA capping activity occurs in a pentameric turret. We report a full atomic model of CPV built from a 3D density map obtained using cryoelectron microscopy. The image data for the 3D reconstruction were acquired exclusively from a CCD camera. Our structure shows that the enzymatic domains of the pentameric turret of CPV are topologically conserved and that there are five unique channels connecting the guanylyltransferase and methyltransferase regions. This structural organization reveals how the channels guide nascent mRNA sequentially to guanylyltransferase, 7-N-methyltransferase, and 2'-O-methyltransferase in the turret, undergoing the highly coordinated mRNA capping activity. Furthermore, by fitting the deduced amino acid sequence of the protein VP5 to 120 large protrusion proteins on the CPV capsid shell, we confirmed that this protrusion protein is encoded by CPV RNA segment 7.

Three-dimensional structure of the hepatitis B core antigen particle truncated at residue 154.

The three-dimensional structure of recombinant hepatitis B core antigen (HBcAg) particles truncated at residue 154 (HBcAg-154) was determined to 7.8 Å resolution by cryo-electron microscopy (cryoEM) and computer reconstruction. The capsid of HBcAg-154 is mainly constituted by α-helical folds, highly similar to that of HBcAg-149. The C-terminal region between residues 155 and 183 of the core protein is more crucial to the encapsidation of RNA, and the short C-terminal tail of HBcAg-154 results in a nearly empty capsid.

Effect of phosphoric acid pretreatment on enzymatic hydrolysis of microcrystalline cellulose.

Microcrystalline cellulose (MCC) was pretreated with phosphoric acid at 323K for 10h. X-ray diffraction (XRD) and Atomic Force Microscope (AFM) analyses revealed that the fiber surface morphology of pretreated MCC (P-MCC) were uneven and rough with the crystalline diffraction peaks of P-MCC decreased to a distinct range. The X-ray Photoelectron Spectroscopy (XPS) analysis showed that the uneven and rough surface of P-MCC could enhance the adsorption of cellulose to the molecular surface of cellulose, which is one of the key factors affecting enzymatic hydrolysis of cellulose. A reversible first order kinetics was employed to describe the adsorption kinetics of cellulase to MCC and P-MCC, and the adsorption rate constants of MCC and P-MCC were found to be 0.016, 0.024, 0.041, and 0.095, 0.149, 0.218min(-1), respectively at 278K, 293K and 308K. The activation energies of MCC and P-MCC hydrolysis reactions were found to be 22.257 and 19.721kJ mol(-1). The major hydrolysis products of MCC and P-MCC were cellobiose and glucose. Hydrolysis of MCC for 120h resulted in yields of glucose (7.21%), cellobiose (13.16%) and total sugars (20.37%). However, after the pretreatment with phosphoric acid, the corresponding sugar yields resulted from enzymatic hydrolysis of P-MCC were increased to 24.10%, 41.42%, and 65.52%; respectively, which were 3.34, 3.15, and 3.22 times of the sugars yields from enzymatic hydrolysis of MCC.

Structural comparisons of hepatitis B core antigen particles with different C-terminal lengths.

Core protein of hepatitis B virus (HBV) with various C-terminal lengths (residue 154, 164, 167 and 183) can self-assemble into recombinant hepatitis B core antigen (HBcAg) particles. To understand the RNA encapsidation mechanism of HBV, the three-dimensional structures of these particles were reconstructed by cryo-electron microscopy (cryoEM). Detailed structural comparisons showed that their capsid structures are highly similar, while the RNA content is increased upon the retention of more amino acid residues at the C-terminus of core protein, suggesting the crucial role of the basic C-terminal tail on determining the genome size.

Dissolution of microcrystalline cellulose in phosphoric acid--molecular changes and kinetics.

In this study, we aimed to dissolve microcrystalline cellulose (MCC) with phosphoric acid to obtain high-quality fermentable saccharides. MCC was directly dissolved in phosphoric acid (the concentration was 83%) for 10 hours at temperatures of 30, 50, and 70 degrees C. The structural changes of MCC were determined in detail with X-ray powder diffraction, solid-state cross-polarization magic angle spinning (13)C-NMR, and X-ray photoelectron spectroscopy. The kinetics of MCC decrystallization during treatment with phosphoric acid was also compared at 30, 50, and 70 degrees C. With the assumption of first order kinetics, the Arrhenius parameters of K, A(0) and E(a) were calculated. The rate constants of decrystallization reaction (K) were 0.06, 0.17, and 0.12 h(-1) respectively. The pre-exponential factor (A(0)) was 1.2 x 10(6) h(-1), and the activation energy (E(a)) was 42.4 kJ/mol.

[Adsorption of cyromazine on five typical soils in China].

Batch equilibrium experiments were used to reveal cyromazine adsorption on five kinds of soils, namely Ali-Perudic Ferrosols collected from Yingtan of Jiangxi, Udic Argosols collected from Nanjing and Gleyic-Stagnic Anthrosols collected from Changshu of Jiangsu, Ustic Cambosols collected from Fengqiu of Henan, and Udic Isohumosols collected from Hailun of Heilongjiang. Results show that the experimental data are best described by the Freundlich and Langmuir model, while fitted successfully by the linear model. Different adsorption behaviors of Cyromazine are observed in the five tested soils, with the lgK(f) values varying from 1.6505 (cambosols), 1.6715 (argosols) and 1.7153 (ferrosols) to 2.4579 (anthrosols) and 2.6557 (isohumosols). Moreover, the Kf values are in a positive correlation to the OM of the soil (r = 0.989) but significantly negative correlated to soil pH (r = -0.938). The free energy of sorption ranged from -20.8 to -23.0 kJ/mol, indicated that the adsorption could be largely attributed to the physical adsorption.

Structure of the hepatitis E virus-like particle suggests mechanisms for virus assembly and receptor binding.

Hepatitis E virus (HEV), a small, non-enveloped RNA virus in the family Hepeviridae, is associated with endemic and epidemic acute viral hepatitis in developing countries. Our 3.5-A structure of a HEV-like particle (VLP) shows that each capsid protein contains 3 linear domains that form distinct structural elements: S, the continuous capsid; P1, 3-fold protrusions; and P2, 2-fold spikes. The S domain adopts a jelly-roll fold commonly observed in small RNA viruses. The P1 and P2 domains both adopt beta-barrel folds. Each domain possesses a potential polysaccharide-binding site that may function in cell-receptor binding. Sugar binding to P1 at the capsid protein interface may lead to capsid disassembly and cell entry. Structural modeling indicates that native T = 3 capsid contains flat dimers, with less curvature than those of T = 1 VLP. Our findings significantly advance the understanding of HEV molecular biology and have application to the development of vaccines and antiviral medications.

The truncated virus-like particles of C6/36 cell densovirus: implications for the assembly mechanism of brevidensovirus.

The brevidensovirus is one of the smallest viruses in the world and the capsid of Aedes albopictus C6/36 cell densovirus (C6/36DNV) is the simplest and most compact capsid in brevidensovirus. To understand the assembly mechanism of icosahedral-virus capsid from this simplest model, we tried to express various lengths of virus proteins (VPs) of C6/36DNV in Bac-to-Bac system and evaluate their self-assembly capacities in insect Spodoptera frugiperda 9 (Sf9) cells. The result showed that the N-terminal GGSG sequence (residue 23-26), highly conserved glycine-rich region in Parvoviridae, and C-terminal GTGGVVTCMP (residue 344-353) were essential for capsid assembly, while the N-terminal nuclear localization signal, GTKRKR sequence (residue 15-20), was nonessential for the virus-like particles (VLPs) assembly, but did effect the formation of crystalline arrays in infected Sf9 cells. These information provided clues for how icosahedral-virus capsids formed and showed the potential of C6/36DNV-VLPs becoming a powerful nanoparticle vector.

Structure comparisons of Aedes albopictus densovirus with other parvoviruses.

Parvoviridae is a family of the smallest viruses known with a wide variety of hosts. The capsid structure of the Aedes albopictus C6/36 cell densovirus (C6/36 DNV) at 1.2-nm resolution was obtained by electron cryomicroscopy (cryoEM) and three-dimensional (3D) image reconstruction. Structure comparisons between the C6/36 DNV and other parvoviruses reveal that the degree of structural similarity between C6/36 DNV and the human parvovirus B19 is higher than that between C6/36 DNV and other insect parvoviruses. The amino acid sequence comparisons of structural and non-structural proteins also reveal higher levels of similarity between C6/36 DNV and parvovirus B19 than those between C6/36 DNV and other parvoviruses. These findings indicate that C6/36 DNV is closely related to the human virus B19, and the former might evolve from the human species other than from other insect viruses.

The pathogenicity of mosquito densovirus (C6/36DNV) and its interaction with dengue virus type II in Aedes albopictus.

When Aedes albopictus larvae were infected with C6/36 densovirus (C6/36DNV), the mortality reached 97.46% within 21 days for those larvae infected at the first day after hatching, and 14.17% for control. A real-time quantitative polymerase chain reaction (qPCR) was used to trace the dynamic change of the quantity of C6/36DNV genomes in the larvae and the adults, and to study the interaction of C6/36DNV with dengue virus type II(DEN-II) in mosquitoes. It showed that C6/36DNV could persist in the adults that could transmit C6/36DNV vertically to the next generation. The quantity of C6/36DNV after DEN-II infection increased by 10(2)~10(3) times in the C6/36DNV-positive mosquitoes, and the quantity of DEN-II in the C6/36DNV-positive mosquitoes was about 100 times lower than that in the C6/36DNV-negative mosquitoes, which suggested that DEN-II could remarkably stimulate the reproduction of C6/36DNV, while C6/36DNV persisted in mosquitoes could inhibit the reproduction of DEN-II. The study throws light on C6/36DNV as a possible biologic control agent against dengue virus and Ae. albopictus.

Crystal structure of the severe acute respiratory syndrome (SARS) coronavirus nucleocapsid protein dimerization domain reveals evolutionary linkage between corona- and arteriviridae.

The causative agent of severe acute respiratory syndrome (SARS) is the SARS-associated coronavirus, SARS-CoV. The nucleocapsid (N) protein plays an essential role in SARS-CoV genome packaging and virion assembly. We have previously shown that SARS-CoV N protein forms a dimer in solution through its C-terminal domain. In this study, the crystal structure of the dimerization domain, consisting of residues 270-370, is determined to 1.75A resolution. The structure shows a dimer with extensive interactions between the two subunits, suggesting that the dimeric form of the N protein is the functional unit in vivo. Although lacking significant sequence similarity, the dimerization domain of SARS-CoV N protein has a fold similar to that of the nucleocapsid protein of the porcine reproductive and respiratory syndrome virus. This finding provides structural evidence of the evolutionary link between Coronaviridae and Arteriviridae, suggesting that the N proteins of both viruses have a common origin.