SARS-CoV-2 rapidly spreads among humans via social networks, with social mixing and network characteristics potentially facilitating transmission. However, limited data on topological structural features has hindered in-depth studies. Existing research is based on snapshot analyses, preventing temporal investigations of network changes. Comparing network characteristics over time offers additional insights into transmission dynamics. We examined confirmed COVID-19 patients from an eastern Chinese province, analyzing social mixing and network characteristics using transmission network topology before and after widespread interventions. Between the two time periods, the percentage of singleton networks increased from 38.9$ \% $ to 62.8$ \% $$ (p<0.001) $; the average shortest path length decreased from 1.53 to 1.14 $ (p<0.001) $; the average betweenness reduced from 0.65 to 0.11$ (p<0.001) $; the average cluster size dropped from 4.05 to 2.72 $ (p=0.004) $; and the out-degree had a slight but nonsignificant decline from 0.75 to 0.63 $ (p=0.099). $ Results show that nonpharmaceutical interventions effectively disrupted transmission networks, preventing further disease spread. Additionally, we found that the networks’ dynamic structure provided more information than solely examining infection curves after applying descriptive and agent-based modeling approaches. In summary, we investigated social mixing and network characteristics of COVID-19 patients during different pandemic stages, revealing transmission network heterogeneities.

In this study, the mitochondrial genome of Eulaelaps silvestris, which parasitizes Apodemus chevrieri, was sequenced and assembled to fill the gap in understanding the molecular evolution of the genus Eulaelaps. The E. silvestris mitochondrial genome is a double-stranded DNA molecule with a length of 14 882 bp, with a distinct AT preference for base composition and a notably higher AT content than GC content. The arrangement between genes is relatively compact, with a total of 10 gene intergenic regions and 12 gene overlap regions. All protein-coding genes had a typical ATN initiation codon, and only 2 protein-coding genes had an incomplete termination codon T. Out of the 13 protein-coding genes, the 5 most frequently used codons ended in A/U, with only 1 codon ending in G/C had an relative synonymous codon usage value >1. Except for trnS1 and trnS2, which lacked the D arm, all other tRNAs were able to form a typical cloverleaf structure; and there were a total of 38 mismatches in the folding process of tRNA genes. Unlike the gene arrangement order of the arthropod hypothetical ancestor, the E. silvestris mitochondrial genome underwent fewer rearrangements, mainly near tRNA genes and control regions. Both the maximum likelihood tree and the Bayesian tree showed that the family Haemogamasidae is most closely related to the family Dermanyssidae. The results not only provide a theoretical basis for studying the phylogenetic relationships of the genus Eulaelaps, but also provide molecular evidence that the family Haemogamasidae does not belong to the subfamily Laelapidae.

Coronavirus disease 2019 (COVID-19) asymptomatic cases are hard to identify, impeding transmissibility estimation. The value of COVID-19 transmissibility is worth further elucidation for key assumptions in further modelling studies. Through a population-based surveillance network, we collected data on 1342 confirmed cases with a 90-days follow-up for all asymptomatic cases. An age-stratified compartmental model containing contact information was built to estimate the transmissibility of symptomatic and asymptomatic COVID-19 cases. The difference in transmissibility of a symptomatic and asymptomatic case depended on age and was most distinct for the middle-age groups. The asymptomatic cases had a 66.7% lower transmissibility rate than symptomatic cases, and 74.1% (95% CI 65.9–80.7) of all asymptomatic cases were missed in detection. The average proportion of asymptomatic cases was 28.2% (95% CI 23.0–34.6). Simulation demonstrated that the burden of asymptomatic transmission increased as the epidemic continued and could potentially dominate total transmission. The transmissibility of asymptomatic COVID-19 cases is high and asymptomatic COVID-19 cases play a significant role in outbreaks.

Late Palaeozoic igneous rock associations in response to subduction, accretion, and final closure of the eastern Palaeo-Asian Ocean play a significant role in understanding the geodynamic evolution of the southeastern Central Asian Orogenic Belt. Previous studies have identified a Permian arc magmatic belt associated with the southward-dipping subduction of the eastern Palaeo-Asian Ocean along the Solonker–Changchun suture zone. The genetic mechanism and associated geodynamic settings are of great importance in deciphering the evolution of the eastern Palaeo-Asian Ocean. This paper presents zircon U–Pb–Hf isotope and whole-rock geochemical analyses for a suite of magmatic rocks including the early Permian diorite porphyrites (ca. 281.0 Ma), andesites (ca. 276 Ma) and rhyolites (ca. 275 Ma) in the Kulun region. The diorite porphyrites and andesites have high SiO2 and total alkali contents, and low MgO contents and Mg no. values, with enrichments in large ion lithophile elements and depletions in high-field-strength elements. These geochemical characteristics, together with low-Sr and high-Yb contents, a weak concave-upward shape of middle rare earth elements and negative Eu anomalies, suggest that these intermediate igneous rocks were generated by partial melting of amphibolitic lower crust at a crustal depth of 30–40 km. The rhyolites have heterogeneous isotopic compositions, with ϵHf(t) values and TDM2 ages of –20.8 to +0.5 and 3578∼1494 Ma, implying that they were likely derived from partial melting of a mixed source dominated by recycled ancient crust with minor juvenile crustal materials. The rhyolites show potassic affinity with relatively high K2O and very low Na2O, which was attributed to liquid immiscibility of felsic magma and subsequent limited fractional crystallization of plagioclase. The regional igneous associations, metamorphic events, and coeval sedimentary rocks along the Solonker–Changchun suture zone indicate that the early Permian igneous rocks were formed in an active continental arc environment in response to southward subduction of the eastern Palaeo-Asian Ocean.

This study is performed to figure out how the presence of diabetes affects the infection, progression and prognosis of 2019 novel coronavirus disease (COVID-19), and the effective therapy that can treat the diabetes-complicated patients with COVID-19. A multicentre study was performed in four hospitals. COVID-19 patients with diabetes mellitus (DM) or hyperglycaemia were compared with those without these conditions and matched by propensity score matching for their clinical progress and outcome. Totally, 2444 confirmed COVID-19 patients were recruited, from whom 336 had DM. Compared to 1344 non-DM patients with age and sex matched, DM-COVID-19 patients had significantly higher rates of intensive care unit entrance (12.43% vs. 6.58%, P = 0.014), kidney failure (9.20% vs. 4.05%, P = 0.027) and mortality (25.00% vs. 18.15%, P < 0.001). Age and sex-stratified comparison revealed increased susceptibility to COVID-19 only from females with DM. For either non-DM or DM group, hyperglycaemia was associated with adverse outcomes, featured by higher rates of severe pneumonia and mortality, in comparison with non-hyperglycaemia. This was accompanied by significantly altered laboratory indicators including lymphocyte and neutrophil percentage, C-reactive protein and urea nitrogen level, all with correlation coefficients >0.35. Both diabetes and hyperglycaemia were independently associated with adverse prognosis of COVID-19, with hazard ratios of 10.41 and 3.58, respectively.

Late Mesozoic igneous rocks are important for deciphering the Mesozoic tectonic setting of NE China. In this paper, we present whole-rock geochemical data, zircon U–Pb ages and Lu–Hf isotope data for Early Cretaceous volcanic rocks from the Tulihe area of the northern Great Xing’an Range (GXR), with the aim of evaluating the petrogenesis and genetic relationships of these rocks, inferring crust–mantle interactions and better constraining extension-related geodynamic processes in the GXR. Zircon U–Pb ages indicate that the rhyolites and trachytic volcanic rocks formed during late Early Cretaceous time (c. 130–126 Ma). Geochemically, the highly fractionated I-type rhyolites exhibit high-K calc-alkaline, metaluminous to weakly peraluminous characteristics. They are enriched in light rare earth elements (LREEs) and large-ion lithophile elements (LILEs) but depleted in high-field-strength elements (HFSEs), with their magmatic zircons ϵHf(t) values ranging from +4.1 to +9.0. These features suggest that the rhyolites were derived from the partial melting of a dominantly juvenile, K-rich basaltic lower crust. The trachytic volcanic rocks are high-K calc-alkaline series and exhibit metaluminous characteristics. They have a wide range of zircon ϵHf(t) values (−17.8 to +12.9), indicating that these trachytic volcanic rocks originated from a dominantly lithospheric-mantle source with the involvement of asthenospheric mantle materials, and subsequently underwent extensive assimilation and fractional crystallization processes. Combining our results and the spatiotemporal migration of the late Early Cretaceous magmatic events, we propose that intense Early Cretaceous crust–mantle interaction took place within the northern GXR, and possibly the whole of NE China, and that it was related to the upwelling of asthenospheric mantle induced by rollback of the Palaeo-Pacific flat-subducting slab.

Seaweeds have numerous biologically active ingredients, such as polysaccharides, polyphenols and carotenoids, that are beneficial to human health. Although these benefits might be related to the synthesis, secretion or reabsorption of uric acid, no studies have explored the relationship between seaweeds consumption and hyperuricaemia (HUA) in the general population. The aim of this study was to investigate whether seaweeds consumption is related to HUA in a large-scale adult population. A cross-sectional study was conducted with 32 365 adults (17 328 men and 15 037 women) in Tianjin, People’s Republic of China. Frequency of seaweeds consumption was assessed by a validated self-administered FFQ. HUA was defined as serum uric acid levels >420 μmol/L in men and >350 μmol/L in women. The association between seaweeds consumption and HUA was assessed by multiple logistic regression analysis. Restricted cubic spline functions were used for non-linearity tests. The prevalence of HUA in men and women was 21·17 % and 5·93 %, respectively. After adjustments for potential confounding factors, the OR (95 % CI) for HUA across seaweed consumption (g/1000 kcal per d) were 1·00 (reference) for level 1, 0·91 (95 % CI 0·81, 1·02) for level 2; 0·90 (95 % CI 0·81, 1·01) for level 3; 0·86 (95 % CI 0·78, 0·97) for level 4 in men and 0·90 (95 % CI 0·73, 1·10) for level 2; 0·82 (95 % CI 0·67, 1·00) for level 3; 0·84 (95 % CI 0·68, 1·03) for level 4 in women, respectively. A negative correlation between seaweeds consumption and HUA in males but not in females was observed. Further studies are needed to explore the causal relationship.

Interstitial cells of Cajal (ICC) play an essential role in the motility of the gastrointestinal tract, and they have been identified in many laboratory animals and in humans. However, the information of ICC in lower animals is still very limited. In the present study, ICC were identified in the gastric muscularis mucosae of an amphibian—the Chinese giant salamander, by c-Kit immunohistochemistry and transmission electron microscopy. ICC showed c-Kit immunoreactivity and had spindle-shaped cell bodies and 1–2 long processes. ICC were located between smooth muscle cells (SMC) in gastric muscularis mucosae. Ultrastructurally, ICC appeared as polygon-, spindle-, and awl-shaped with long cytoplasmic prolongations between SMC. ICC had distinctive characteristics, such as nuclei with peripheral electron-dense heterochromatin, caveolae, and abundant intracytoplasmatic vacuoles, mitochondria, and rough endoplasmic reticula. Moreover, lamellar bodies and two types of condensed granules were observed in the cytoplasm of ICC. Notably, ICC establish close contacts with each other. Moreover, ICC establish gap junctions with SMC. In addition, ICC were frequently observed close to nerve fibers. In summary, the present study demonstrated the presence of ICC in the gastric muscularis mucosae of the Chinese giant salamander.

Seed reserves play vital roles in seed germination and seedling growth and their variation may be related to various environment factors, plant traits and phylogenetic history. Here, the evolutionary correlation associated with seed mass and altitude and carbon (C), nitrogen (N) and phosphorus (P) allocation of seeds among 253 alpine herbaceous plants was tested. In this study, phylogeny had strong limitations on nutrient allocation of seeds across species, and species from younger phylogenetic groups tended to have higher N and P contents, which might be considered as the evolutionary selection of seed plants. Higher seed N and P content would help seedlings to gain more survival chance and stronger competitive capacity, and their progeny would be more likely to be preserved. When phylogeny was considered, altitude only had a significant positive effect on P content, but the negative effects on seed mass were all expressed. The independent effects of altitude and seed mass suggest that the nutrient allocation of seeds might be affected by both environment and plant traits. In addition, altitude and seed mass displayed partial overlapping effects on nutrient allocation of seeds. The negative effects of seed mass were affected slightly by altitude, whereas altitude only had a significant positive effect on P content when seed mass was controlled. Above all, seed P content showed obvious and general correlations with seed mass, altitude and age of clade, which indicated that higher seed P content might be an adaptive selection of species associated with growth and survival of progeny.

Combining density functional theory calculations and temperature programmed desorption (TPD) experiments, the adsorption behavior of various sulfur containing compounds, including C2H5SH, CH3SCH3, tetrahydrothiophene, thiophene, benzothiophene, dibenzothiophene, and their derivatives on the coordinately unsaturated sites of Mo27Sx model nanoparticles, are studied systematically. Sulfur molecules with aromaticity prefer flat adsorption than perpendicular adsorption. The adsorption of nonaromatic molecules is stronger than the perpendicular adsorption of aromatic molecules, but weaker than the flat adsorption of them. With gradual hydrogenation (HYD), the binding affinity in the perpendicular adsorption modes increases, while in flat adsorption modes it increases first, then decreases. Significant steric effects on the adsorption of dimethyldibenzothiophene were revealed in perpendicular adsorption modes. The steric effect, besides weakening adsorption, could also activate the S–C bonds through a compensation effect. Finally, by comparing the theoretical adsorption energies with the TPD results, we suggest that HYD and direct-desulfurization path may happen simultaneously, but on different active sites.

Objective: To study the relationship of Nε-(carboxymethyl)-lysine level (CML) with microstructure changes of white matter (WM), and cognitive impairment in patients with type 2 diabetes mellitus (T2DM) and to discuss the potential mechanism underlying T2DM-associated cognitive impairment. Methods: The study was performed in T2DM patients (n=22) with disease course ≥5 years and age ranging from 65 to 75 years old. A control group consisted of 25 sex- and age-matched healthy volunteers. Fractional anisotropy (FA) of several WM regions was analyzed by diffusion tensor imaging scan. Plasma CML levels were measured by enzyme-linked immunosorbent assay, and cognitive function was assessed by Mini-Mental State Examination and Montreal cognitive assessment (MoCA). Results: The total Mini-Mental State Examination score in the patient group (25.72±3.13) was significantly lower than the control group (28.16±2.45) (p<0.05). In addition, the total MoCA score in the patient group (22.15±3.56) was significantly lower than the control group 25.63±4.12) (p<0.01). In the patient group, FA values were significantly decreased in the corpus callosum, cingulate fasciculus, inferior fronto-occipital fasciculus, parietal WM, hippocampus, and temporal lobes relative to corresponding regions of healthy controls (p<0.05). Plasma CML level was negatively correlated with average FA values in the global brain (r=−0.58, p<0.01) and MoCA scores (r=−0.47, p<0.05). Conclusions: In T2DM, WM microstructure changes occur in older patients, and elevations in CML may play a role in the development of cognitive impairment.

The objective of the present study was to investigate age-related differences in erythrocyte membrane fluidity (EMF) and changes in antioxidant capacity following supplementation. A total of seventy-four children were randomly divided into two groups: group A1 was the placebo-controlled group and group A2 was supplemented daily with 600 μg retinol, 1·0 mg β-carotene, 100 mg tocopherol, 300 mg ascorbic acid and 200 μg Se. A total of ninety young people were randomly divided into B1 and B2 groups, and ninety-one elderly subjects were divided into C1 and C2 groups. Groups B1 and C1 were placebo-controlled groups, and groups B2 and C2 were daily supplemented with 900 μg retinol, 1·5 mg β-carotene, 200 mg tocopherol, 500 mg ascorbic acid and 400 μg Se. Results showed that plasma malondialdehyde (MDA) was 5·35 μmol/l in children, which was lower than in young and elderly people. The MDA levels of the young and elderly individuals in the treated groups were significantly lower compared with the control groups, but the supplementation did not alter MDA levels in children. At baseline, there was a lower value of polarisation (ρ) and microviscosity (η) in children, indicating a higher EMF, than in both the young and elderly subjects. After the 2-month trial, the ρ and η values of young and elderly subjects in the treated groups decreased significantly in comparison with the placebo groups, indicating an increase in EMF. In conclusion, there was a background of higher MDA levels and lower EMF in young and elderly people than in children, which could be improved by antioxidant supplementation.

The potential relationship between the establishment of Foot-and-mouth disease virus (FMDV) persistent infection and gene variation was identified by investigating the variation of VP1 and 3ABC genes from yellow cattle persistent infection isolates. Five yellow cattle were inoculated on their tongue with 1.0×104 ID50/ml of FMDV O/Akesu/58 strain. After displaying clinical or subclinical signs, they probably became asymptomatic carriers. Oesophageal–pharyngeal fluids were collected monthly from the carriers with a probang and inoculated into a baby hamster kidney cell line (BHK-21); 12 FMDV isolates were obtained. The VP1 and 3ABC genes of the 12 isolates were then amplified by reverse-transcriptase polymerase chain reaction (RT-PCR). Cloning and sequencing revealed that the homology of the VP1 nucleotide and amino-acid sequence of all the isolates was above 98%, with no base deletion or insertion. When compared with the O/Akesu/58 FMDV strain, the homology of the VP1 nucleotide sequence of the isolates was only 85%, and that of the deduced amino-acid sequence only 90%.There were several nucleotide mutations in the VP1 gene of the isolates, including 16 consistent nucleotide mutations, with only two of them leading to a change in amino acid (I56→T, A210→E). Moreover, it was found that four nucleotide points and three amino-acid points had transversions among all isolates. The 3ABC gene had only 13 nucleotide transversions and five amino-acid mutations. It was presumed that persistent FMDV infection might have little connection with variation in the VP1 and 3ABC genes, and was probably related to other structural protein gene and key factors.

Spermatogonial stem cells (SSCs), which were isolated from chicken (Gallus gallus) embryo testes 16 days after laying, were cultured, subcultured, and induced into adipocytes in vitro. The differentiated cells were identified by oil red-O staining. Dexamethasone, insulin and 3-isobutyl-1-methylxanthine (IBMX) were tested for their induction potential. About 7–21 days after induction, SSCs differentiated into adipocytes, and the resulting adipocytes strongly expressed peroxisome proliferation activation receptor-γ (PPAR-γ). The assay outcome showed that an optimal treatment consisted of dexamethasone, insulin and IBMX application for 3 days and insulin for 1 day (3 cycles), then insulin for 21 days. The differentiation ratio was 85%, better than the combined use of dexamethasone, insulin and IBMX (P<0.01). However, the combination of the three derivatives triggered a stronger induction than any of them used alone (P<0.01). This study has demonstrated the potential of chicken embryonic SSCs to differentiate in vitro into adipocytes.

Extended abstract of a paper presented at Microscopy and Microanalysis 2006 in Chicago, Illinois, USA, July 30 – August 3, 2005

Smooth and uniform Ag/AgO nanoshells (about 3–4 nm) on carboxylated polystyrene latex particles were prepared by electrostatic attraction between negatively charged –COO− on the surface of carboxylated polystyrene latex particles and positively charged Ag(NH3)2+ in the solution, and subsequent decomposition of the silver complex. The resultant nanoparticles were characterized with Fourier transform infrared, transmission electron microscopy, scanning electron microscopy, and x-ray diffraction. The effects of reducing agents, the amount of NaOH and temperature on the morphology of hybrid latex particles were discussed.