In recent years, intracranial thrombectomy stent has been an important method to treat ischemic stroke caused by acute thrombosis. In this paper, a new intracranial thrombectomy stent with a fish scale-like structure was designed and its mechanical properties were studied by a finite element method. The porosity of all stents was more than 80%. The space occupation ratio (SOR) of the stents increased linearly with the increase of strut thickness, while the strut width had little effect on SOR. The maximum equivalent stress and strain, the directional deformation and overall radial load of the stent decreased with the increase of strut thickness, however, the strut width has little impact on these parameters. The stents with 0.2 mm strut width and the thickness of 0.15 and 0.20 mm had better radial load performance, and the stent with 0.2 mm strut width and 0.15 mm strut thickness had better contact performance with the vessel wall and displayed better flexibility. Therefore, the present study provides a theoretical basis for the design of new intracranial thrombectomy stent.

Dysregulation in hepatic lipid synthesis by excess dietary carbohydrate intake are often relevant with the occurrence of fatty liver, and therefore the thorough understanding of the regulation of lipid deposition and metabolism seems crucial to search for potential regulatory targets. In the present study, we examined TG accumulation, lipid metabolism-related genes expression, the enzyme activities of lipogenesis-related enzymes, the protein levels of transcription factors or genes involving lipogenesis in the livers of yellow catfish fed five dietary carbohydrate sources, such as glucose, corn starch, sucrose, potato starch and dextrin, respectively. Generally speaking, compared to other carbohydrate sources, dietary glucose promoted the TG accumulation, up-regulated the lipogenic enzyme activities and gene expressions, and down-regulated mRNA expression of genes involved in lipolysis and SUMO modification pathways. Further studies found that SREBP1, key transcriptional factors relevant with lipogenic regulation, was modified by SUMO1. Mutational analyses found two important sites for sumoylation modification (K254R and K264R) in SREBP1. Mutant SREBPs lacking lysine 264 up-regulated the transactivation capacity on an SREBP-responsive promoter. Glucose reduced the SUMOylation level of SREBP1 and promoted the protein expression of SREBP1 and its target gene SCD1, indicating that SUMOylation of SREBP1 mediated glucose-induced hepatic lipid metabolism. Our study elucidated the molecular mechanism of dietary glucose increasing hepatic lipid deposition and found that the SREBP-dependent transactivation was regulated by SUMO1 modification, which served as a new target for the transcriptional programs governing lipid metabolism.

The European Society for Clinical Nutrition and Metabolism (ESPEN) guidelines recommend Royal Free Hospital-Nutritional Prioritizing Tool (RFH-NPT) to identify malnutrition risk in patients with liver disease. However, little is known about the application of RFH-NPT to screen for the risk of malnutrition in China, where patients primarily suffer from hepatitis virus-related cirrhosis. A total of 155 cirrhosis patients without liver cancer or uncontrolled comorbid illness were enrolled in this prospective study. We administered the Nutritional Risk Screening 2002 (NRS-2002), RFH-NPT, Malnutrition Universal Screening Tool(MUST), and Liver Disease Undernutrition Screening Tool (LDUST) to the patients within 24 h after admission and performed follow-up observations for 1.5 years. The RFH-NPT and NRS-2002 had higher sensitivities (64.8% and 52.4%) and specificities (60% and 70%) than the other tools with regard to screening for the malnutrition risk in cirrhotic patients. The prevalence of nutritional risk was higher under the use of RFH-NPT against the NRS-2002(63% vs. 51%). RFH-NPT tended more easily to detect the malnutrition risk in patients with advanced Child-Pugh classes (B and C) and lower MELD scores (<15) compared with NRS-2002. The RFH-NPT score was an independent predictive factor for mortality. Patients identified as being at high malnutrition risk with the RFH-NPT had a higher mortality rate than those at a low risk; the same result was not obtained with the NRS-2002. Therefore, we suggest that using RFH-NPT improves the ability of clinicians to predict malnutrition risk in patients with cirrhosis primarily caused by hepatitis virus infection at an earlier stage.

Effects of dietary supplemental stachyose on cecal skatole concentration, hepatic cytochrome P450 (CYP450, CYP) mRNA expressions and enzymatic activities in broilers were evaluated. Arbor Acre commercial mixed male and female chicks were assigned randomly into six treatments. The positive control (PC) diet was based on corn-soybean meal, the negative control (NC) diet was based on corn-nonsoybean meal. The NC diet was then supplemented with 4, 5, 6, and 7 g/kg stachyose to create experimental diets, named S-4, S-5, S-6, and S-7, respectively. Each diet was fed to 6 replicates of 10 birds from days 1 to 49. On day 49, the cecal skatole concentrations in the PC, S-4, S-5, S-6, and S-7 groups were lower than those in the NC group by 42.28%, 23.68%, 46.09%, 15.31%, and 45.14% (P < 0.01). The lowest pH value was observed in the S-5 group (P < 0.05). The stachyose-fed groups of broilers had higher cecal acetate and propionate levels compared to control groups, and propionate levels in the S-6, S-7 groups were higher than those in the S-4 and S-5 groups (P < 0.001). The highest CYP3A4 expression was found in the S-7 group (P < 0.05), but this was not different from PC, S-4, S-5 and S-6 treatment. There was no significant difference in CYP450 (1A2, 2D6, 3A4) enzymatic activities among the groups (P > 0.05). In conclusion, cecal skatole levels can be influenced by dietary stachyose levels, and 5 g/kg of stachyose in diet was suggested.

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.

This study aimed to investigate the clinical characteristics and to analyse the epidemiological features of coronavirus disease 2019 (COVID-19) patients during convalescence. In this study, we enrolled 71 confirmed cases of COVID-19 who were discharged from hospital and transferred to isolation wards from 6 February to 26 March 2020. They were all employees of Zhongnan Hospital of Wuhan University or their family members of which three cases were <18 years of age. Clinical data were collected and analysed statistically. Forty-one cases (41/71, 57.7%) comprised medical faculty, young and middle-aged patients (aged ⩽60 years) accounted for 81.7% (58/71). The average isolation time period for all adult patients was 13.8 ± 6.1 days. During convalescence, RNA detection results of 35.2% patients (25/71) turned from negative to positive. The longest RNA reversed phase time was 7 days. In all, 52.9% of adult patients (36/68) had no obvious clinical symptoms, and the remaining ones had mild and non-specific clinical symptoms (e.g. cough, sputum, sore throat, disorders of the gastrointestinal tract etc.). Chest CT signs in 89.7% of adult patients (61/68) gradually improved, and in the others, the lesions were eventually absorbed and improved after short-term repeated progression. The main chest CT manifestations of adult patients were normal, GGO or fibre streak shadow, and six patients (8.8%) had extrapulmonary manifestations, but there was no significant correlation with RNA detection results (r = −0.008, P > 0.05). The drug treatment was mainly symptomatic support therapy, and antibiotics and antiviral drugs were ineffective. It is necessary to re-evaluate the isolation time and standard to terminate isolation for discharged COVID-19 patients.

The satellite constellation with automatic dependent surveillance-broadcast on-board is of great importance for air traffic surveillance due to its multiple advantages compared with traditional methods. Although some research has been conducted on satellite constellation design based on coverage performance, the findings cannot entirely satisfy all the requirements of air traffic surveillance owing to the lack of analysis on inter-satellite links and network transmission. This paper presents a novel design of a low earth orbit satellite constellation network to solve this problem. Based on the requirements of space-based surveillance, an evaluation model of constellation performance is proposed concerning coverage, link and transmission. The simulation results show that the evaluation model can reflect the performance of a satellite constellation network designed for a space-based surveillance system, and a 55-satellite constellation design scheme with fairly good performance can fulfil the function of global real-time air traffic surveillance.

In December, 2019, an infection outbreak occurred in Wuhan of unknown cause, which attracts intense attention. Shortly after the virus was identified with the name of severe acute respiratory syndrome coronavirus 2(SARS-CoV-2), the epidemic of coronavirus disease 2019 (COVID-19) broke out and an information storm occurred. At that time, two important aspects: the stage and the links of epidemic, were unclear. Answers to the questions, what are the sources, how do infections occur, and who will be affected should be clarified as the outbreak continues to evolve. Furthermore, the epidemic process and the stage of epidemic should be explored and discussed. Based on information of SARS, middle east respiratory syndrome(MERS) and COVID-19, the links of epidemic (the sources, the routes of infection, and the susceptible population) will be discussed as well as the role of the natural and the social factors. Epidemiology characteristics of patients will be traced based on current information.

For the guarantee of the long-distance transport of the bunches of China Initiative Accelerator Driven System (CIADS), a new scheme is proposed that extra magnetic field is used in the accelerator-target coupling section before the windowless target to minimize the self-modulation (SM) mechanism. Particle-in-cell simulations are carried out to study the influence of the solenoidal magnetic field on the self-modulation mechanism when long proton bunches move in the background plasmas. The long proton bunches used in the simulations are similar to these in the linear accelerator of CIADS. It is found that the presence of the solenoidal magnetic field will significantly inhibit the self-modulation process. For the strong magnetic field, the longitudinal separation and transverse focusing of the long bunches disappear. We attribute these phenomena to the reason that the strong solenoidal magnetic field restricts the transverse movement of plasma electrons. Thus, there are not enough electrons around the bunch to compensate the space charge effect. Moreover, without transverse current, the longitudinal pinched effect disappears, and the long bunch can not be separated into small pulses anymore.

During recent stratigraphical and micropaleontological investigations of the Gulupu section in Tüna, Yadong, of the Eocene Zhepure Formation, numerous holoplanktonic mollusks (pteropods) were recovered. Four species, assignable to two genera of pteropods (including Limacina yadongensis new species) were systematically described and illustrated, and a gastropod-bivalve biofacies was identified. This is the first report of Eocene (Ypresian) pteropods in southern Tibet; the same stratum also yields many other neritic faunas. The data presented in this study suggest that a semi-closed restricted gulf in the Tüna area existed and the occurrence of pteropods in Tüna may indicate transport from more open, deep water by oceanic currents during early Eocene. Based on the analysis of paleogeographical distribution of pteropods, it indicates that a Tethys seaway existed during the early Eocene (Ypresian).

UUID: http://zoobank.org/7eb6f8dd-a973-4834-986a-310008476eb0

Primary liver cancer is the third leading cause of cancer-related death worldwide. Most patients are diagnosed at late stages with poor prognosis; thus, identification of modifiable risk factors for primary prevention of liver cancer is urgently needed. The well-established risk factors of liver cancer include chronic infection with hepatitis B virus (HBV) or hepatitis C virus (HCV), heavy alcohol consumption, metabolic diseases such as obesity and diabetes, and aflatoxin exposure. However, a large proportion of cancer cases worldwide cannot be explained by current known risk factors. Dietary factors have been suspected as important, but dietary aetiology of liver cancer remains poorly understood. In this review, we summarised and evaluated the observational studies of diet including single nutrients, food and food groups, as well as dietary patterns with the risk of developing liver cancer. Although there are large knowledge gaps between diet and liver cancer risk, current epidemiological evidence supports an important role of diet in liver cancer development. For example, exposure to aflatoxin, heavy alcohol drinking and possibly dairy product (not including yogurt) intake increase, while intake of coffee, fish and tea, light-to-moderate alcohol drinking and several healthy dietary patterns (e.g. Alternative Healthy Eating Index) may decrease liver cancer risk. Future studies with large sample size and accurate diet measurement are warranted and need to consider issues such as the possible aetiological heterogeneity between liver cancer subtypes, the influence of chronic HBV or HCV infection, the high-risk populations (e.g. cirrhosis) and a potential interplay with host gut microbiota or genetic variations.

With more and more missions around the Moon, a communication/navigation constellation around the Moon is necessary. Halo orbits, due to their unique geometry, are extensively studied by researchers for this purpose. A dedicated survey is carried out in this work to analyse the coverage ability of halo orbits. It is found that a two-satellite constellation is enough for continuous one-fold coverage of the north or the south polar regions but never both. A three-satellite constellation is enough for continuous one-fold coverage of both north and south polar regions. A four-satellite constellation can cover nearly 100% of the whole lunar surface. In addition, the coverage ability of another special orbit – distant retrograde orbit (DRO) – is analysed for the first time in this study. It is found that three satellites on DROs can cover 99·8% of the lunar surface, with coverage gaps at polar caps. A four-satellite constellation moving on spatial DROs can cover nearly the whole lunar surface. By combining halo orbits and DROs, we design a five-satellite constellation composed of three halo orbit satellites and two DRO satellites. This constellation can provide 100% continuous one-fold coverage of the whole lunar surface.