Rapid 3D roll-up of gas-phase planar gold clusters and affinity and alienation for Mg and Ge: A theoretical study of MgGeAun (n=1-12) clusters.

A cluster is a special matter level above a single atom and between macroscopic and microscopic matter, and it is an important bridge to understanding the relationship between the structure and function of matter. Here, we perform a comprehensive theoretical study of 2D planar Aun (n = 1-12) clusters doped with both magnesium and germanium. Two interesting results are found, namely the rapid 3D "roll-up" structural growth of the GeMgAun (n = 1-12) cluster ground state isomers, and the relative "alienation" of the different sizes of the Aun (n = 1-12) cluster framework towards the Ge atom, and the relative "affinity" towards the Mg atom. This study will not only enrich the data on gold-based clusters but will also provide a simple and clear theoretical guide for the 3D structuring of planar clusters, i.e. the doping of different classes of "affinition" and "alienatation" atoms.

Systematic research on gallium atom-doped neutral small- and medium-sized gas-phase magnesium clusters: A DFT study of GaMgn (n=2-12) clusters.

Structure, stability, charge transfer, chemical bonding, and spectroscopic properties of Ga atom-doped neutral Mgn (n = 2-12) clusters have been systematically investigated by CALYPSO and density functional theory. All cluster structures are based on "tetrahedral" and "yurt-like" growth except for GaMg2. The ground state isomer of GaMg8 with high symmetry structure is predicted to be the best-fit candidate for the "magic" cluster because of its excellent stability. Natural bond orbital calculations reveal that Ga and Mg atoms play the role of electron acceptor and donor in all ground state isomers, while the orbitals in both Ga and Mg are sp-hybridized. Most importantly, chemical bonding studies based on atom-in-molecular theory have shown that the lowest-energy state of GaMg4 is so special, in that it has not only the critical size for the appearance of Mg-Mg covalent bonds, but also the only cluster that has both Ga-Mg covalent and non-covalent bonds. Finally, theoretical calculations of IR and Raman spectra of all ground state isomers indicate that the spectra of these clusters are observable in the low-frequency band, and thus they can be identified by spectroscopic experiments. Furthermore, the bond heterogeneity of the Ga-Mg in the GaMg4 ground state isomer has also been specifically investigated, including the fixed GaMg4 structure with Mg atoms added in different directions, as well as ab initio molecular dynamics sampling at different temperatures.

Structural Genomic Analysis of SARS-CoV-2 and Other Coronaviruses.

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) is the causative agent of the coronavirus disease 2019 (COVID-19) pandemic. In this study, we conducted a comparative analysis of the structural genes of SARS-CoV-2 and other CoVs. We found that the sequence of the E gene was the most evolutionarily conserved across 200 SARS-CoV-2 isolates. The E gene and M gene sequences of SARS-CoV-2 and NC014470 CoV were closely related and fell within the same branch of a phylogenetic tree. The absolute diversity of E gene and M gene sequences of SARS-CoV-2 isolates was similar to that of common CoVs (C-CoVs) infecting other organisms. The absolute diversity of the M gene sequence of the KJ481931 CoV that can infect humans was similar to that of SARS-CoV-2 and C-CoVs infecting other organisms. The M gene sequence of KJ481931 CoV (infecting humans), SARS-CoV-2 and NC014470 CoV (infecting other organisms) were closely related, falling within the same branch of a phylogenetic tree. Patterns of variation and evolutionary characteristics of the N gene and S gene were very similar. These data may be of value for understanding the origins and intermediate hosts of SARS-CoV-2.

Computational Exploration on the Structural and Optical Properties of Gold-Doped Alkaline-Earth Magnesium AuMgn (n = 2-12) Nanoclusters: DFT Study.

Using CALYPSO crystal search software, the structural growth mechanism, relative stability, charge transfer, chemical bonding and optical properties of AuMgn (n = 2-12) nanoclusters were extensively investigated based on DFT. The shape development uncovers two interesting properties of AuMgn nanoclusters contrasted with other doped Mg-based clusters, in particular, the planar design of AuMg3 and the highly symmetrical cage-like of AuMg9. The relative stability study shows that AuMg10 has the robust local stability, followed by AuMg9. In all nanoclusters, the charge is transferred from the Mg atoms to the Au atoms. Chemical bonding properties were confirmed by ELF analysis that Mg-Mg formed covalent bonds in nanoclusters larger than AuMg3. Static polarizability and hyperpolarizability calculations strongly suggest that AuMg9 nanocluster possesses interesting nonlinear optical properties. Boltzmann distribution weighted average IR and Raman spectroscopy studies at room temperature verify that these nanoclusters are identifiable by spectroscopic experiments. Finally, the average bond distance and average nearest neighbor distance were fully investigated.

The diagnostic and prognostic role of myocardial injury biomarkers in hospitalized patients with COVID-19.

OBJECTIVE: The aim of this study was to systematically and comprehensively evaluate the diagnostic and prognostic value of myocardial injury biomarkers in COVID-19 patients. METHODS: This is a retrospective cohort study of confirmed COVID-19 patients that were admitted to the Renmin Hospital of Wuhan University from January 30, 2020 to February 15, 2020. RESULTS: Receiver operating characteristic (ROC) curve analysis demonstrated that cTnI-ultra had the highest area under the curve (AUC) at 0.855, with a sensitivity of 67.3% and a specificity of 88.7% for the prediction of in-hospital mortality. Patients with higher troponin I-ultra (cTnI-ultra), creatinine kinase-myocardial band (CK-MB), and N-terminal pro-B-type natriuretic peptide (NT-proBNP) were associated with higher mortality, compared to those who lower levels. The multivariable cox regression indicated that age (hazard ratio (HR) 3.450, 95% confidence interval (CI) 1.627-7.314, P = 0.001), coronary heart disease (HR 1.855, 95% CI 1.006-3.421; P = 0.048), elevated cTnI-ultra (HR 3.083, 95% CI 1.616-5.883, P = 0.001), elevated CK-MB (HR 2.907, 95% CI 1.233-6.854; P = 0.015), and elevated NT-proBNP (HR 5.776, 95% CI 2.272-14.682; P < 0.001) were associated with in-hospital mortality. CONCLUSIONS: cTnI-ultra might be the best predictor of in-hospital mortality among myocardial injury biomarkers. Elevated cTnI-ultra, CK-MB, and NT-proBNP were independent biomarkers of the mortality in COVID-19 patients.

Searching new structures of beryllium-doped in small-sized magnesium clusters: Be2 Mgn Q (Q = 0, -1; n = 1-11) clusters DFT study.

Using CALYPSO method to search new structures of neutral and anionic beryllium-doped magnesium clusters followed by density functional theory (DFT) calculations, an extensive study of the structures, electronic and spectral properties of Be2 Mgn Q (Q = 0, -1; n = 2-11) clusters is performed. Based on the structural optimization, it is found that the Be2 Mgn Q (Q = 0, -1) clusters are shown by tetrahedral-based geometries at n = 2-6 and tower-like-based geometries at n = 7-11. The calculations of stability indicate that Be2 Mg5 Q=0 , Be2 Mg5 Q=-1 , and Be2 Mg8 Q=-1 clusters are "magic" clusters with high stability. The NCP shows that the charges are transferred from Mg atoms to Be atoms. The s- and p-orbitals interactions of Mg and Be atoms are main responsible for their NEC. In particular, chemical bond analysis including molecular orbitals (MOs) and chemical bonding composition for magic clusters to further study their stability. The results confirmed that the high stability of these clusters is due to the interactions between the Be atom and the Mg5 or Mg8 host. Finally, theoretical calculations of infrared and Raman spectra of the ground state of Be2 Mgn Q (Q = 0, -1; n = 1-11) clusters were performed, which will be absolutely useful for future experiments to identify these clusters.

Estimation of incubation period and serial interval of COVID-19: analysis of 178 cases and 131 transmission chains in Hubei province, China.

A novel coronavirus disease, designated as COVID-19, has become a pandemic worldwide. This study aims to estimate the incubation period and serial interval of COVID-19. We collected contact tracing data in a municipality in Hubei province during a full outbreak period. The date of infection and infector-infectee pairs were inferred from the history of travel in Wuhan or exposed to confirmed cases. The incubation periods and serial intervals were estimated using parametric accelerated failure time models, accounting for interval censoring of the exposures. Our estimated median incubation period of COVID-19 is 5.4 days (bootstrapped 95% confidence interval (CI) 4.8-6.0), and the 2.5th and 97.5th percentiles are 1 and 15 days, respectively; while the estimated serial interval of COVID-19 falls within the range of -4 to 13 days with 95% confidence and has a median of 4.6 days (95% CI 3.7-5.5). Ninety-five per cent of symptomatic cases showed symptoms by 13.7 days (95% CI 12.5-14.9). The incubation periods and serial intervals were not significantly different between male and female, and among age groups. Our results suggest a considerable proportion of secondary transmission occurred prior to symptom onset. And the current practice of 14-day quarantine period in many regions is reasonable.

Systematic Theoretical Study on Structural, Stability, Electronic, and Spectral Properties of Si2 Mg n Q (Q = 0, ±1; n = 1-11) Clusters of Silicon-Magnesium Sensor Material.

By using CALYPSO searching method and Density Functional Theory (DFT) method at the B3LYP/6-311G (d) level of cluster method, a systematic study of the structures, stabilities, electronic and spectral properties of Si2 Mg n Q (n = 1-11; Q = 0, ±1) clusters of silicon-magnesium sensor material, is performed. According to the calculations, it was found that when n > 4, most stable isomers in Si2 Mg n Q (n = 1-11; Q = 0, ±1) clusters of silicon-magnesium sensor material are three-dimensional structures. Interestingly, although large size Si2 Mg n Q clusters show cage-like structures, silicon atoms are not in the center of the cage, but tend to the edge. The Si2 Mg 1 , 5 , 6 , 8 - 1 and Si2 Mg 13 , 4 , 7 , 9 , 10 + 1 clusters obviously differ to their corresponding neutral structures, which are in good agreement with the calculated values of VIP, AIP, VEA, and AEA. |VIP-VEA| values reveal that the hardness of Si2Mgn clusters decreases with the increase of magnesium atoms. The relative stabilities of neutral and charged Si2 Mg n Q (n = 1-11; Q = 0, ±1) clusters of silicon-magnesium sensor material is analyzed by calculating the average binding energy, fragmentation energy, second-order energy difference and HOMO-LUMO gaps. The results reveal that the Si2 Mg 3 0 , Si2 Mg 3 - 1 , and Si2 Mg 3 + 1 clusters have stronger stabilities than others. NCP and NEC analysis results show that the charges in Si2 Mg n Q (n = 1-11; Q = 0, ±1) clusters of silicon-magnesium sensor material transfer from Mg atoms to Si atoms except for Si2 Mg 1 + 1 , and strong sp hybridizations are presented in Si atoms of Si2 Mg n Q clusters. Finally, the infrared (IR) and Raman spectra of all ground state of Si2 Mg n Q (n = 1-11; Q = 0, ±1) clusters of silicon magnesium sensor material are also discussed.

Treatment models of cardiac rehabilitation in patients with coronary heart disease and related factors affecting patient compliance.

Coronary heart disease is a serious threat to human health. In China, medical care for the population has been focused on therapy with little follow-up of treated patients. The efficacy of therapy; however, is highly dependent on post-therapy recovery. Cardiac rehabilitation can significantly enhance patient physical strength and help delay and prevent the development of coronary atherosclerosis. Although the clinical significance of cardiac rehabilitation has been established, the compliance of patients is generally low. In efforts to improve patient compliance, domestic and foreign researchers have extensively studied and applied treatment models of cardiac rehabilitation according to the specific conditions and cultural background of each country. This study aimed to review the treatment models of cardiac rehabilitation in patients with coronary heart disease and related factors affecting patient compliance to provide a better perspective of how patients with coronary heart disease can benefit from cardiac rehabilitation.

kmcEx: memory-frugal and retrieval-efficient encoding of counted k-mers.

MOTIVATION: K-mers along with their frequency have served as an elementary building block for error correction, repeat detection, multiple sequence alignment, genome assembly, etc., attracting intensive studies in k-mer counting. However, the output of k-mer counters itself is large; very often, it is too large to fit into main memory, leading to highly narrowed usability. RESULTS: We introduce a novel idea of encoding k-mers as well as their frequency, achieving good memory saving and retrieval efficiency. Specifically, we propose a Bloom filter-like data structure to encode counted k-mers by coupled-bit arrays-one for k-mer representation and the other for frequency encoding. Experiments on five real datasets show that the average memory-saving ratio on all 31-mers is as high as 13.81 as compared with raw input, with 7 hash functions. At the same time, the retrieval time complexity is well controlled (effectively constant), and the false-positive rate is decreased by two orders of magnitude. AVAILABILITY AND IMPLEMENTATION: The source codes of our algorithm are available at github.com/lzhLab/kmcEx. SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.