Acute suppurative terminal cholangitis:Clinical characteristics of a new subtype of acute cholangitis

Background:Acute suppurative terminal cholangitis(ASTC)is rarer than acute obstructive cholangitis and is not well studied.To explore this subtype of acute cholangitis,we described our clinical experience with ASTC.Methods:We performed a retrospective review of patients with ASTC admitted to our center from September 2014 to August 2020.We analyzed their clinical characteristics,including etiology,clinical manifestations,imaging features,treatment and prognosis.Results:A total of 32 ASTC patients were included in the analysis.The majority of the patients had a history of biliary operations,and clinical manifestations were occult and atypical.The positive rate of bacterial culture was 46.9%.All the patients had typical imaging features on computed tomography and magnetic resonance imaging.Treatment with effective antibiotics was provided as soon as diagnosis was established.After treatment,most patients had a good outcome.Elevated levels of total bilirubin,aspartate aminotransferase,procalcitonin and gamma-glutamyltransferase were the characteristics of critically ill patients and were associated with relatively poor prognosis.Conclusions:Our results demonstrated that ASTC should be recognized as a new subtype of acute cholangitis,and that earlier diagnosis and more personalized treatments are needed.

Ferrets: A powerful model of SARS-CoV-2

The rapid spread of severe acute respiratory syndrome coronavirus 2(SARS-CoV-2) in recent years not only caused a global pandemic but resulted in enormous social,economic,and health burdens worldwide.Despite considerable efforts to combat coronavirus disease 2019(COVID-19),various SARS-CoV-2 variants have emerged,and their underlying mechanisms of pathogenicity remain largely unknown.Furthermore,effective therapeutic drugs are still under development.Thus,an ideal animal model is crucial for studying the pathogenesis of COVID-19 and for the preclinical evaluation of vaccines and antivirals against SARS-CoV-2 and variant infections.Currently,several animal models,including mice,hamsters,ferrets,and nonhuman primates(NHPs),have been established to study COVID-19.Among them,ferrets are naturally susceptible to SARS-CoV-2 infection and are considered suitable for COVID-19 study.Here,we summarize recent developments and application of SARS-CoV-2 ferret models in studies on pathogenesis,therapeutic agents,and vaccines,and provide a perspective on the role of these models in preventing COVID-19 spread.

Approximate error correction scheme for three-dimensional surface codes based reinforcement learning

Quantum error correction technology is an important method to eliminate errors during the operation of quantum computers.In order to solve the problem of influence of errors on physical qubits,we propose an approximate error correction scheme that performs dimension mapping operations on surface codes.This error correction scheme utilizes the topological properties of error correction codes to map the surface code dimension to three dimensions.Compared to previous error correction schemes,the present three-dimensional surface code exhibits good scalability due to its higher redundancy and more efficient error correction capabilities.By reducing the number of ancilla qubits required for error correction,this approach achieves savings in measurement space and reduces resource consumption costs.In order to improve the decoding efficiency and solve the problem of the correlation between the surface code stabilizer and the 3D space after dimension mapping,we employ a reinforcement learning(RL)decoder based on deep Q-learning,which enables faster identification of the optimal syndrome and achieves better thresholds through conditional optimization.Compared to the minimum weight perfect matching decoding,the threshold of the RL trained model reaches 0.78%,which is 56%higher and enables large-scale fault-tolerant quantum computation.

Human microbiome is a diagnostic biomarker in hepatocellular carcinoma

Background:Hepatocellular carcinoma(HCC)is the third leading cause of cancer mortality worldwide.Increasing evidence indicates a close relationship between HCC and the human microbiota.Herein,we reviewed the important potential of the human microbiota as a diagnostic biomarker of HCC.Data sources:Several innovative studies have investigated the characteristics of the gut and oral micro-biomes in patients with HCC and proposed that the human microbiome has the potential to be a diag-nostic biomarker of HCC.Literature from February 1999 to February 2019 was searched in the PubMed database using the keywords"microbiota"or"microbiome"or"microbe"and"liver cancer"or"hepato-cellular carcinoma",and the results of clinical and experimental studies were analyzed.Results:Specific changes occur in the human microbiome of patients with HCC.Moreover,the gut mi-crobiome and oral microbiome can be used as non-invasive diagnostic biomarkers for HCC.Furthermore,they also have certain diagnostic potential for precancerous diseases of HCC.The diagnostic potential of the blood microbiota and ascites microbiota in HCC will be gradually discovered in the future.Conclusions:The human microbiome is valuable to the diagnosis of HCC and provides a novel strategy for targeted therapy of HCC.The human microbiome may be widely used in the diagnosis,treatment and prognosis for multiple system diseases or cancers in the future.

Analytical solution of velocity distribution for flow through submerged large deflection flexible vegetation

An analytical solution for predicting the vertical distribution of streamwise mean velocity in an open channel flow with submerged flexible vegetation is proposed when large bending occurs. The flow regime is separated into two horizontal layers： a vegetation layer and a free water layer. In the vegetation layer, a mechanical analysis for the flexible vegetation is conducted, and an approximately linear relationship between the drag force of bending vegetation and the streamwise mean flow velocity is observed in the case of large deflection, which differes significantly from the case of rigid upright vegetation. Based on the theoretical analysis, a linear streamwise drag force-mean flow velocity expression in the momentum equation is derived, and an analytical solution is obtained. For the free water layer, a new expression is presented, replacing the traditional logarithmic velocity distribution, to obtain a zero velocity gradient at the water surface. Finally, the analytical predictions are compared with published experimental data, and the good agreement demonstrates that this model is effective for the open channel flow through the large deflection flexible vegetation.

Total closure of pancreatic section for end-to-side pancreaticojejunostomy decreases incidence of pancreatic fistula in pancreaticoduodenectomy

BACKGROUND： Postoperative pancreatic fistula （POPF） is a serious complication and results in prolonged hospitalization and high mortality. The present study aimed to evaluate the safety and effectiveness of total closure of pancreatic section for end-to-side pancreaticojejunostomy in pancreaticoduodenectomy （PD）. METHODS： This was a prospective randomized clinical trial comparing the outcomes of PD between patients who un- derwent total closure of pancreatic section for end-to-side pancreaticojejunostomy （Group A） vs those who underwent conventional pancreaticojejunostomy （Group B）. The primary endpoint was the incidence of pancreatic fistula. Secondary endpoints were morbidity and mortality rates. RESULTS： One hundred twenty-three patients were included in this study. The POPF rate was significantly lower in Group A than that in Group B （4.8% vs 16.7%, P〈0.05）. About 38.3% patients in Group B developed one or more complications; this rate was 14.3% in Group A （P〈0.01）. The wound/abdomi- nal infection rate was also much higher in Group B than that in Group A （20.0% vs 6.3%, P〈0.05）. Furthermore, the average hospital stays of the two groups were 18 days in Group A, and 24 days in Group B, respectively （P〈0.001）. However, there was no difference in the probability of mortality, biliary leakage,delayed gastric emptying, and pulmonary infection between the two groups. CONCLUSION： Total closure of pancreatic section for end-to- side pancreaticojejunostomy is a safe and effective method for pancreaticojejunostomy in PD.

RING finger and WD repeat domain 3 regulates proliferation and metastasis through the Wnt/β-catenin signalling pathways in hepatocellular carcinoma

BACKGROUND Hepatocellular carcinoma(HCC)exhibits high invasiveness and mortality rates,and the molecular mechanisms of HCC have gained increasing research interest.The abnormal DNA damage response has long been recognized as one of the important factors for tumor occurrence and development.Recent studies have shown the potential of the protein RING finger and WD repeat domain 3(RFWD3)that positively regulates p53 stability in response to DNA damage as a therapeutic target in cancers.AIM To investigate the relationship between HCC and RFWD3 in vitro and in vivo and explored the underlying molecular signalling transduction pathways.METHODS RFWD3 gene expression was analyzed in HCC tissues and adjacent normal tissues.Lentivirus was used to stably knockdown RFWD3 expression in HCC cell lines.After verifying the silencing efficiency,Celigo/cell cycle/apoptosis and MTT assays were used to evaluate cell proliferation and apoptosis.Subsequently,cell migration and invasion were assessed by wound healing and transwell assays.In addition,transduced cells were implanted subcutaneously and injected into the tail vein of nude mice to observe tumor growth and metastasis.Next,we used lentiviral-mediated rescue of RFWD3 shRNA to verify the phenotype.Finally,the microarray,ingenuity pathway analysis,and western blot analysis were used to analyze the regulatory network underlying HCC.RESULTS Compared with adjacent tissues,RFWD3 expression levels were significantly higher in clinical HCC tissues and correlated with tumor size and TNM stage(P<0.05),which indicated a poor prognosis state.RFWD3 silencing in BEL-7404 and HCC-LM3 cells increased apoptosis,decreased growth,and inhibited the migration in shRNAi cells compared with those in shCtrl cells(P<0.05).Furthermore,the in vitro results were supported by the findings of the in vivo experiments with the reduction of tumor cell invasion and migration.Moreover,the rescue of RFWD3 shRNAi resulted in the resumption of invasion and metastasis in HCC cell lines.Finally,gene expression profiling and subsequent experimental verification revealed that RFWD3 might influence the proliferation and metastasis of HCC via the Wnt/β-catenin signalling pathway.CONCLUSION We provide evidence for the expression and function of RFWD3 in HCC.RFWD3 affects the prognosis,proliferation,invasion,and metastasis of HCC by regulating the Wnt/β-catenin signalling pathway.

微相分离结合氢键复合构筑弹性体

通过嵌段聚合物的微相分离和高分子氢键复合,使用聚苯乙烯-b-聚丙烯酸-b-聚苯乙烯(SAS)三嵌段聚合物和聚氧化乙烯(PEO)均聚物构筑了具有多层次结构的弹性体(SA/E).聚丙烯酸(PAA)与PEO形成柔性的氢键复合物(PAA/PEO),刚性的聚苯乙烯(PS)与PAA和PEO不相容而发生微相分离,PS作为交联点连接着柔性的PAA/PEO.与PAA/PEO氢键复合物相比,SA/E弹性体力学性能明显提升,通过控制PS质量分数可调节弹性体的模量和强度等力学性能.SA/E弹性体表现出湿度敏感性.并且弹性体经拉伸训练后可获得一定的取向性,弹性回复率保持在98%以上.本弹性体在湿度传感、柔性器件、医用材料等领域具有潜在应用,为构筑新型弹性体提供思路.

Stabilize and Reinforce Hydrogen-Bonded Polymer Complex Elastic Fiber by Catechol Chemistry and Coordination

Hydrogen-bonded polymer complex fiber of poly(ethylene oxide)(PEO)and poly(acrylic acid)(PAA)shows rubber elasticity in ambient environment,but the fiber has relatively low strength and weak stability.We apply the catechol chemistry and metal coordination to stabilize and strengthen the PEO/PAA fiber.PAA is grafted with dopamine(Dopa),and then combines with PEO to prepare fiber.PAA-Dopa in the fiber is crosslinked through oxidation induced dismutation and the metal ions are introduced through coordination.The cross-linking and coordination greatly improve the stability of the fiber against the erosion of alkaline water.Among four different metal coordination fibers,PEO/PAA-Dopa/Cu fiber keeps the excellent extensibility(~1000%)and presents much higher initial modulus(~7 MPa),ultimate strength(~20 MPa),and toughness(~60 MJ/m^(3))than its precursor PEO/PAA fiber.In addition,PEO/PAA-Dopa/Cu fiber shows quick recovery and large energy dissipation ratio compared with the PEO/PAA fiber.The distinct mechanical properties enhancement of the hydrogen-bonded complex fiber is attributed to the synergy of hydrogen bonds,coordination and covalent bond cross-linking.

湿度对高分子氢键复合物纤维力学行为的影响

高分子复合物具有刺激响应特性,随环境变化表现出结构或性能转变.以聚丙烯酸(PAA)作为氢键给体,分别以聚乙烯吡咯烷酮(PVPON)、聚2-乙基-2-唑啉(PEOX)和聚环氧乙烷(PEO)作为受体,制备了3种氢键复合物纤维. 3种纤维的力学性能都随湿度变化而变化,且对湿度的依赖性与高分子氢键复合强度相关.通过动态力学测试,利用时间-湿度叠加方法构建了高分子氢键复合物纤维的模量-频率主曲线,呈现了较宽时间范围内的力学松弛现象.为湿度响应的高分子复合物材料的开发及应用提供指导与支持.

The structure of turbulent flow through submerged flexible vegetation

The hydrodynamics of turbulent flow through submerged flexible vegetation is investigated in a flume using acoustic Doppler velocimetery(ADV)measurements.The flow characteristics such as the energetics and momentum transfer derived from convcntional spectral and quadrant analyses are considered as the flow encounters a finite vegetation patch.Consistent with numerous canopy flow experiments,a shear layer and coherent vortex structures near the canopy top emerge caused by Kelvin-Helmholtz instabilities after the flow equilibrates with the vegetated layer.These in stabilities are commonly attributed to velocity differences between non-vegetated and vegetated canopy layers in agreement with numerous experiments and simulations conducted on dense rigid canopies.The power-spectral density function for vertical velocity turbulent fluctuations at different downstream positions starting from the edge of the vegetation layer are also computed.For a preset water depth,the dominant dimensionless frequency is found to be surprisingly invariant around 0.027 despite large differences in vegetation densities.The ejection and sweep events significantly contribute to the Reynolds stresses near the top of the vegetation.The momentum flux carried by ejections is larger than its counterpart carried by the sweeps above the canopy top.However,the momentum flux carried by sweeps is larger below the top of the canopy.

Predictions of bulk velocity for open channel flow through submerged vegetation

Vegetation is of great significance in river ecosystems in terms of hydrodynamics,water environment and ecology.The question of how to predict the bulk velocity in channel flow through submerged vegetation is currently a hot topic in hydraulics research.The present study addresses this question.The various formulae used for bulk velocity estimation in previous work were reviewed and compared.The main novelty of this paper is that a new expression of friction factor is proposed as a function of two dimensionless factors,and the number of tuning parameters is less than that in previous work.A comparison of measured and calculated data was conducted for flow through submerged rigid and flexible vegetation.The comparison showed that the proposed new model can make more accurate predictions than previous models.It is envisaged that the proposed formulation can be usefully employed in eco-hydraulics predictions.

Dispersion features of pollutants in a compound channel with vegetated floodplains

The planting of the vegetation on the floodplain helps the ecological restoration,which is the main form of the river’s ecological corridor.Therefore,the current research of the river dynamics focuses on the water movement under a compound channel with the vegetated floodplains.Two simulated vegetation species are selected in this paper for the flume simulation experiments of the floodplain vegetation,and the compound channel is divided into three subregions in the transverse direction.The Navier-Stokes equation and the eddy viscosity theory are applied to obtain the transverse distribution of the depth-averaged velocity and the results agree well with the experimental data.This paper proposes a new method based on the analytical solution of the flow velocity distribution to calculate the average flow velocity in each section.Calculation results can effectively simulate the average flow velocity of the measured sections.The description of the pollutant transport processes in a moving stream requires a refined determination of the dispersion coefficients in the compound channel.The process of the pollutant concentrations in each zone and the reasons for their occurrence are elucidated on the basis of the experimental results.Simultaneously,the measured values of the longitudinal dispersion coefficients are obtained by the“routing procedure,”and a two-zone model of the pollutant dispersion is constructed on the basis of the hydrodynamic study.The prediction method for the longitudinal dispersion coefficients is also presented.Applying the predicted and measured section average flow velocities to the two-zone model to predict the longitudinal dispersion coefficient,and the average relative errors are only 4.17%,7.15%,respectively.This result indicates that the two-zone model can effectively predict the longitudinal dispersion coefficients.The calculation methods for the longitudinal dispersion coefficients from—various studies are compared.The results reveal that the predicted values of these calculation methods are all larger than the measured values,indicating that the vegetation has a considerable influence on the dispersion process.This study comprehensively shows the dispersion features of the pollutants and provides a theoretical basis for the planning and the design of the vegetated ecological corridors.

A voltammetric sensor for simultaneous determination of lead,cadmium and zinc on an activated carbon fiber rod

In this work, a simple, low cost and sensitive voltammetric sensor was developed for the simultaneous detection of lead （Pb2＋）, cadmium （Cd2＋）, and zinc （Zn2＋） ions based on a disposable carbon fiber rod （CFR）. The important factors to enhance the sensing property were creation of a clean surface by dealing with CFR at a high potential and electrochemical deposition of bismuth （Bi） film to improve the accumulation of heavy metal ions. The morphology and conductivity of such activated CFR was characterized by scanning electron microscopy and electrochemical impedance spectroscopy, respectively. In terms of application, differential pulse anodic stripping voltammetry （DPASV） was employed for the simultaneous detection of Pb2＋, Cd2＋, and Zn2＋ on Bi film-coated activated CFR. Experimental parameters, such as the pH value of buffer solution, stirring speed and enrichment factors were optimized. Under optimal conditions, the DPASV peak currents showed good linear relationships with Pb2＋, Cd2＋ and Zn2＋ concentrations in the range of 0.5-2.25 μg/L, 0.5-4.0 μg/L and 1.0- 4.0 μg/L with detection limits of 0.1, 0.3 and 1.0 μg/L （SIN = 3）, respectively. Finally, the proposed analysis system was successfully utilized for the simultaneous detection of Pb2＋, Cd2＋, and Zn2＋ contents in rice samples. This study indicated that Bi film-coated activated CFR based DPASV sensor can be a promising and reliable tool for rapid analysis of emergency Dollution affairs of heavv metal ions in food.

Langmuir-Blodgett Films of C_(60)-end-capped Poly(ethylene oxide)

Buckyballs(C_(60)) are linked to one end and two ends of linear poly(ethylene oxide)(PEO) chains through highly efficient click chemistry to obtain giant amphiphilic molecules C_(60)-PEO and C_(60)-PEO-C_(60), respectively. C_(60)-PEO and C_(60)-PEO-C_(60) molecules are spread on water surface and then transferred to solid substrates with Langmuir-Blodgett(LB) film deposition approach. C_(60)-PEO and C_(60)-PEO-C_(60) exhibit fractal growth behavior on the solid substrate under certain conditions owing to the crystallization ability of PEO segment. PEO chain length and the end capped mode both affect the fractal growth pattern.

Fractal Growth of Giant Amphiphiles in Langmuir-Blodgett Films

Fractal structures have attracted considerable scientific interest,and fractal geometry is an effective tool to study the complicated structure and dynamic processes,such as dilation symmetry of disorder structure,percolation,gelation,and metal-insulator transition.Here,we summarized our findings of fractal growth of giant amphiphiles in Langmuir-Blodgett(LB)film.Giant amphiphiles composed of polyhedral oligomeric silsesquioxanes(POSS)derivatives and poly(ethylene oxide)(PEO),with structural diversities of POSS head modification,POSS head number,PEO chain length,are precisely synthesized.The effect of molecular structures and operation parameters on the fractal growth patterns are discussed,in addition,other fractal growth patterns in LB films and in Langmuir films are included,aiming to understand the basic molecular principle of fractal growth in LB system.