Hua Zhang

Bio: Hua Zhang is an academic researcher from Chinese Academy of Sciences. The author has contributed to research in topics: Medicine & Graphene. The author has an hindex of 163, co-authored 1503 publications receiving 116769 citations. Previous affiliations of Hua Zhang include Shenzhen University & Zhengzhou University.

Arrhythmia in patients with severe coronavirus disease (COVID-19): a meta-analysis.

Abstract: OBJECTIVE: Many studies have reported arrhythmia to be associated with coronavirus disease (COVID-19), but no meta-analysis has explored whether arrhythmia is related to COVID-19 severity. Therefore, the purpose of this study was to evaluate arrhythmia in patients with severe and non-severe COVID-19 during the current COVID-19 pandemic. MATERIALS AND METHODS: We searched PubMed, Embase, Web of Science, and the Cochrane Library for case control studies that were published between January 1 and July 25, 2020, and that had data on arrhythmia in patients with COVID-19. Random effects model was used with the odds ratio as the effect size. The frequency of arrhythmia was compared between COVID-19 patients with and without the composite endpoint of severity. We also determined the pooled prevalence of arrhythmia in patients with COVID-19. Publication bias and heterogeneity were considered by using subgroup analyses, meta-regression, and the trim and fill method. RESULTS: A total of 1553 patients with COVID-19 were included in the 5 articles we obtained. Of these, 349 cases (22.47%) and 1204 cases (77.53%) were severely ill and non-severely ill inpatients with COVID-19 pneumonia, respectively. There were 790 (50.87%) male patients. A total of 105 cases (30.09%) of severely ill inpatients with COVID-19 pneumonia had arrhythmia complications, and 34 cases (2.82%) of non-severely ill inpatients with COVID-19 pneumonia had arrhythmia complications. We found arrhythmia to be significantly associated with severely ill inpatients with COVID-19 pneumonia, with a pooled odds ratio of 17.97 (95% CI (11.30, 28.55), p<0.00001). CONCLUSIONS: This study showed that the incidence of arrhythmia in patients with severe COVID-19 was greater than that of those with non-severe COVID-19. Patients with severe COVID-19 had a higher risk of arrhythmia complications, which further showed that COVID-19 may be a risk factor for arrhythmia and that the incidence of arrhythmia may increase with the progression of the disease. More importantly, this meta-analysis graded the reliability of evidence for further basic and clinical research into arrhythmia in patients with COVID-19.

Improved Stretch Formability of AZ31 Magnesium Thin Sheet by Induced {10–12} Tension Twins

Abstract: In order to improve the stretch formability of magnesium alloy sheets, {10–12} tension twins were introduced by pre-compression along the rolling (RD) and transverse directions (TD) with 1.6%, 3.3%, and 5.4% strain levels. Subsequent annealing at 473 K was conducted for 6 h to preserve twinning lamellae. In order to avoid bending–buckling, a special fixture for thin sheet compression has been developed. In addition, hemispherical tests were performed at room temperature. The mechanical properties were improved, while the Lankford value (r-value) decreased and the strain hardening exponent (n-value) increased as the pre-compression level increased compared with the as-received sheet. The stretch formability was also improved. The Erichsen value was dramatically improved the most, from 2.83 mm in the as-received to 5.36 mm and 6.78 mm in TD and RD pre-compressed 5.4% Mg specimens, respectively, which increases by 89% and 139%. The stretch formability was enhanced much more with the pre-compression along the RD as compared to the TD.

Evaluation of Matrix Metalloproteinase Inhibition by Peptide Microarray-Based Fluorescence Assay on Polymer Brush Substrate and in Vivo Assessment.

Abstract: Matrix metalloproteinases (MMPs) are important biomarkers and potential therapeutic targets of tumor. In this report, a peptide microarray-based fluorescence assay is developed for MMPs inhibitors evaluation through immobilization of biotin-modified peptides on the poly(glycidyl methacrylate-co-2-hydroxyethyl methacrylate) (P(GMA-HEMA)) brush-modified glass slides. After biotin is recognized with cyanine 3 (Cy3)-modified avidin (Cy3-avidin), the microarrays can produce strong fluorescence signal. The biotin moieties detach from microarray, when the biotin-modified peptide substrates are specially cleaved by a MMP, resulting in decreased fluorescence intensity of the microarray. The decreasing level of fluorescence intensity is correlated with the MMP inhibition. Nine known MMP inhibitors against MMP-2 and MMP-9 are evaluated by the assay, and the quantitative determination of inhibitory potencies (half maximal inhibitory concentration) are obtained, which are comparable with the literatures. Two biocompatible fluorogenic peptides containing MMP-specific recognition sequences and FAM/Dabcyl fluorophore-quencher pair are designed as activatable reporter probes for sensing MMP-2 and MMP-9 activities in cell and in vivo. The peptide microarray-based results are well verified by the cell inhibition assay and in vitro fluorescence imaging, and further confirmed by the in vivo imaging of HT-1080 tumor-bearing mice.

Transesterification of dimethyl carbonate and phenol to diphenyl carbonate with the bismuth compounds

Abstract: Bismuth oxide was first employed for the transesterification of dimethyl carbonate with phenol to diphenyl carbonate, which has excellent catalytic activity. With 0.4 g Bi2O3, the phenol conversion of 46.4% and transesterification selectivity of 99.9% were attained. The characterization of the used sample by XRD, FTIR and solid-state 13C-NMR indicate that a new compound of bismuth phenoxide was formed with the disappearance of bismuth oxide. It was evidenced that the bismuth phenoxide act as the role of active phase in the transesterification, which was generated facilely in situ by the reaction of bismuth oxide added with the raw material of phenol. The bismuth phenoxide presents excellent reusability, after four consecutive runs, the phenol conversion remained above 45%, and the transesterification selectivity was maintained at 99.9%.

Finite element design of SiC/C functionally graded materials for ablation resistance application

Abstract: Summary Elastic finite element numerical models are used to study residual thermal stresses induced during cooling from the sintering temperature of carbon-based SiC/C functionally graded materials (FGMs) for ablation resistance application. Results show that the stresses can be decreased gradually with increasing the layer number (N). In a preferred system, the optimum compositional distribution exponent (P) and thickness of intermediate graded layers and pure SiC layer are 1.0, 3.6 mm and 1.0 mm, respectively. On basis of the simulated results, SiC/C purpose FGM was fabricated by hot-pressing process. SEM observation shows that this material is characterized by a linearly continuous gradient in the microstructure. Further studies indicate that this material has excellent ablation and thermal shock resistances.

I and i

Abstract: There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality. Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

Fast parallel algorithms for short-range molecular dynamics

Abstract: Three parallel algorithms for classical molecular dynamics are presented. The first assigns each processor a fixed subset of atoms; the second assigns each a fixed subset of inter-atomic forces to compute; the third assigns each a fixed spatial region. The algorithms are suitable for molecular dynamics models which can be difficult to parallelize efficiently—those with short-range forces where the neighbors of each atom change rapidly. They can be implemented on any distributed-memory parallel machine which allows for message-passing of data between independently executing processors. The algorithms are tested on a standard Lennard-Jones benchmark problem for system sizes ranging from 500 to 100,000,000 atoms on several parallel supercomputers--the nCUBE 2, Intel iPSC/860 and Paragon, and Cray T3D. Comparing the results to the fastest reported vectorized Cray Y-MP and C90 algorithm shows that the current generation of parallel machines is competitive with conventional vector supercomputers even for small problems. For large problems, the spatial algorithm achieves parallel efficiencies of 90% and a 1840-node Intel Paragon performs up to 165 faster than a single Cray C9O processor. Trade-offs between the three algorithms and guidelines for adapting them to more complex molecular dynamics simulations are also discussed.

疟原虫var基因转换速率变化导致抗原变异[英]／Paul H, Robert P, Christodoulou Z, et al//Proc Natl Acad Sci U S A

Abstract: 抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1（PfPMP1）与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用，在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员，通过启动转录不同的var基因变异体为抗原变异提供了分子基础。

Electronics and optoelectronics of two-dimensional transition metal dichalcogenides.

Abstract: Single-layer metal dichalcogenides are two-dimensional semiconductors that present strong potential for electronic and sensing applications complementary to that of graphene.