Nonlinear air dynamics of a surface effect ship in small-amplitude waves

In many existing works, the seakeeping motions and air dynamics of a surface effect ship (SES) were assumed to be linear under small-amplitude waves (wave amplitude to wave length ratio ≤ 5%) to enhance the computational efficiency. However, according to SES model test results, it was found that even in small-amplitude waves, the fluctuating air cushion pressure shows significantly nonlinear effects. To precisely reveal this distinctive feature, the origin of nonlinearity was carefully investigated and the air leakage was considered as the main source of nonlinearity based on mathematical analysis in this paper. The reason is that the variance of clearance height under seals is comparable to the clearance height at equilibrium state in small-amplitude waves, which makes the air leakage area intermittently equal to zero without any harmonic variance. Therefore, an efficient partial nonlinear numerical model for the SES dynamics was proposed by combining a linear frequency-domain hydrodynamic model based on the efficient 2.5D methods with a nonlinear time-domain air dynamic model. The nonlinear parts of numerical results from the partial nonlinear model, including the fluctuating air pressure and midship accelerations, agree well with experimental results. The results demonstrate the effectiveness of the partial nonlinear model on the SES seakeeping performance prediction, and confirm that its nonlinearity mainly originates from the air leakage.publishedVersio

Effect of Da-Cheng-Qi Decoction on Pancreatitis-Associated Intestinal Dysmotility in Patients and in Rat Models

The impairment of intestinal motility and related infectious complications are the predominant clinical phenomenon in patients with severe acute pancreatitis (SAP). We aimed to investigate the effects of Da-Cheng-Qi decoction (DCQD) on the gastrointestinal injury in SAP patients and the potential mechanism involved in rats. DCQD was enema administered to 70 patients for 7 days in West China Hospital. Mortality and organ failure during admission were observed and blood samples for laboratory analysis were collected. We also experimentally examined plasma inflammatory cytokines in rat serum and carried the morphometric studies of the gut. Intestinal propulsion index and serum and tissue vasoactive intestinal peptide (VIP) were also detected. Though DCQD did not affect the overall incidence of organ failure, it shortened the average time of paralytic intestinal obstruction and decreased the morbidity of infectious complications in patients with SAP. Compared with untreated rats, the DCQD lowered the levels of proinflammatory cytokine and decreased the mean pathological intestinal lesion scores. The VIP level in intestinal tissue or serum in DCQD group was obviously lowered and intestinal propulsion index was significantly improved. In conclusion, DCQD has good effect on pancreatitis-associated intestinal dysmotility in patients and in rat models

Agro-ecological suitability assessment of Chinese Medicinal Yam under future climate change

Chinese Medicinal Yam (CMY) has been prescribed as medicinal food for thousand years in China by Traditional Chinese Medicine (TCM) practitioners. Its medical benefits include nourishing the stomach and spleen to improve digestion, replenishing lung and kidney, etc., according to the TCM literature. As living standard rises and public health awareness improves in recent years, the potential medicinal benefits of CMY have attracted increasing attention in China. It has been found that the observed climate change in last several decades, together with the change in economic structure, has driven significant shift in the pattern of the traditional CMY planting areas. To identify suitable planting area for CMY in the near future is critical for ensuring the quality and supply quantity of CMY, guiding the layout of CMY industry, and safeguarding the sustainable development of CMY resources for public health. In this study, we first collect 30-year records of CMY varieties and their corresponding phenology and agro-meteorological observations. We then consolidate these data and use them to enrich and update the eco-physiological parameters of CMY in the agro-ecological zone (AEZ) model. The updated CMY varieties and AEZ model are validated using the historical planting area and production under observed climate conditions. After the successful validation, we use the updated AEZ model to simulate the potential yield of CMY and identify the suitable planting regions under future climate projections in China. This study shows that regions with high ecological similarity to the genuine and core producing areas of CMY mainly distribute in eastern Henan, southeastern Hebei, and western Shandong. The climate suitability of these areas will be improved due to global warming in the next 50 years, and therefore, they will continue to be the most suitable CMY planting regions

Fate of the distal aorta following root replacement in Marfan syndrome: a propensity score matched study

ObjectiveThe aortic root is the most frequent segment involved in Marfan syndrome. However, Marfan syndrome is a systemic hereditary connective tissue disorder, and knowledge regarding the outcomes of the native distal aorta after prophylactic aortic root surgery is limited.MethodsFrom April 2010 to December 2020, 226 patients with Marfan syndrome and 1,200 patients without Marfan syndrome who underwent Bentall procedures were included in this study. By propensity score matching, 134 patients were assigned to each group. Clinical manifestations and follow-up data were acquired from hospital records and telephone contact. The cumulative incidence of aortic events was estimated in Marfan and non-Marfan patients with death as a competing risk.ResultsPatients with and without Marfan syndrome had similar baseline characteristics after propensity score matching. Differences in the aortic root (62.25 ± 11.96 vs. 54.03 ± 13.76, P < .001) and ascending aorta (37.71 ± 9.86 vs. 48.16 ± 16.01, P < .001) remained after matching. No difference was observed in the frequency of aortic adverse events between the two groups (10.5% vs. 4.6%, P = 0.106). The cumulative incidence of aortic events was not different between Marfan and non-Marfan patients (15.03% ± 4.72% vs. 4.18% ± 2.06%, P = 0.147). Multivariate Cox regression indicated no significant impact of Marfan syndrome on distal aortic events (HR: 1.172, 95% CI: 0.263–5.230, P = 0.835). Descending and abdominal aortic diameter above normal at the initial procedure were associated with the risk of distal aortic events (HR: 20.735, P = .003, HR: 22.981, P = .002, respectively).ConclusionsNew-onset events of the residual aorta in patients undergoing Bentall procedures between the Marfan and non-Marfan groups were not significantly different. Distal aortic diameter above normal at initial surgery was associated with a higher risk of adverse aortic events

Research progress on degradative solvent extraction of low-rank coals

The degradative solvent extraction of low rank coal is the use of solvents to extract low rank coal under mild conditions, through the dehydration and multi-stage separation of the raw coal： the extraction products with no water content, no ash content, high calorific value properties and excellent thermoplastic properties， and low moisture of the extractive residual coal can be obtained. At the same time, the products have practical application advantages in many fields such as coal coking, advanced fuel and carbon material preparation, which have high added value, and the solvent in this technology has the advantage of being recyclable. Therefore, degradative solvent extraction is one of the effective ways to realize the graded fractionated conversion and utilization of low-rank coal. This review firstly introduces the existing low rank coal upgrading methods, and then reviews the development of degradative solvent extraction, focusing on the various influencing factors, reaction mechanisms, existing processes and product utilization of low rank coal upgrading by degradative solvent extraction. Finally, using the "Web of Science core collection" as the data source, the knowledge graph of coal solvent extraction was carved using CiteSpace scientometric software, and the research themes were analyzed to summarize the research directions and predict the research hotspots, providing some reference value for the research of degradative solution extraction of low-rank coal. The comprehensive analysis shows that: the selection of new low-cost green solvents, structural characterization and high-value utilization of extraction products have high research trends, while in-depth research on extraction mechanism and targeted regulation of extractant properties is needed to further promote the process of large-scale production

The Anzhen Risk Scoring System for Acute Type A Aortic Dissection: A Prospective Observational Study Protocol

Introduction: Acute type A aortic dissection (ATAAD) is a catastrophic disease with fatal outcomes. Malperfusion syndrome (MPS) is a serious complication of ATAAD, with an incidence of 20–40%. Many studies have shown that MPS is the main risk factor for poor ATAAD prognosis. However, a risk scoring system for ATAAD based on MPS is lacking. Here, we designed a risk scoring system for ATAAD to assess mortality through quantitative assessment of relevant organ malperfusion and subsequently develop rational treatment strategies.Methods and analysis: This was a prospective observational study. Patients’ perioperative clinical data were collected to establish a database of ATAAD (N≥3000) and determine whether these patients had malperfusion complications. The Anzhen risk scoring system was established on the basis of organ malperfusion by using a random forest survival model and a logistics model. The better method was then chosen to establish a revised risk scoring system.Ethics and dissemination: This study received ethical approval from the Ethics Committees of Beijing Anzhen Hospital, Capital Medical University (KS2019034-1). Patient consent was waived because biological samples were not collected, and no patient rights were violated. Findings will be disseminated at scientific conferences and in peer-reviewed publications