基于Y-SNP和Y-STR揭示汉族人群父系遗传关系

汉族是中国人口最多的民族,现有研究多集中于汉族人群的起源、迁徙、融合等遗传历史,以及局部地区汉族人群的父系遗传关系,鲜有全局视角下的汉族人群父系遗传结构研究。本研究检测了362份青海、四川和辽宁的汉族无关男性样本,整合已发表文献相关数据,最终获得了国内15个省份16个汉族人群1830人份样本,覆盖89个Y-SNP、16个Y-STR的数据。通过统计Y-SNP单倍群频率、Y-STR单倍型多样性,使用主成分分析(principal component analysis,PCA)、系统发育树、单倍型网络等分析,综合Y-SNP和Y-STR两个反映不同时间尺度的遗传标记,研究不同地区汉族人群之间的遗传分化、汉族人群与其周边少数民族的遗传关系。单倍群频率统计结果显示单倍群O-M175是汉族人群主体单倍群(青海汉族60.53%~广东汉族92.7%),其下游亚单倍群呈现地域差异化分布。单倍群O2-M122高频分布于各地汉族,总体分布趋势北高南低;单倍群O1b-M268分布频率由南向北递减,尤其在岭南地区汉族人群中分布显著;单倍群O1a-M119在中部汉族人群中分布频率较高。汉族人群遗传结构研究表明,其主要分为北部、中部及南部三个聚类簇,其中青海汉族与其他地区汉族存在一定的遗传分化。在合并少数民族的遗传关系研究中,汉族人群彼此之间遗传关系更紧密,但北部汉族与回族遗传关系更近,而南部汉族则与仡佬族、黎族遗传关系更近。总之,本文基于89个Y-SNP和16个Y-STR,系统地研究了中国不同地域的汉族人群的单倍群分布、遗传亚结构及其与周边少数民族的遗传关系,为群体遗传学、法医遗传学补充理论依据,为Y染色体的法医学应用提供数据支撑。Y-SNP单倍群结合Y-STR单倍型对于分析汉族人群遗传亚结构以及法医学应用具有重要作用。

Distribution and risk assessment of heavy metals in surface sediments of coastal mudflats on Leizhou Peninsula,China

Mudflats play a vital role in maintaining the dynamic balance between sea and land.To understand the characteristics,sources,and pollution risks of six heavy metals(As,Cd,Cr,Cu,Hg,and Pb)in the coastal mudflats on the Leizhou Peninsula,257 surface sediment samples were studied using mathematical statistics,correlation analysis,and factor analysis.The results show that the overall concentrations of these heavy metals are low although there are several high abnormal points in the local areas.The strong correlation between these heavy metals indicates that the sources of some of the metals are similar,yet their elemental combinations in different cities(counties)varied.According to the calculated enrichment factor(EF),anthropogenic activity-induced heavy metals were determined in order of decreasing influence:As,Cd,Pb,Cr,Cu,and Hg.The low EF values of Hg indicate that it does not present as a contaminant in the study area,while low values of Cr and Cu from the Lianjiang City suggest that these two metals were also attributed to natural sources.The presence of As,Cd,Cr,Cu,and Pb from the remaining cities(counties)should be influenced by anthropogenic activities.The overall potential ecological risk index indicates that the ecological risks posed by the six analyzed heavy metals to the Leizhou Peninsula mudflats,in order of decreasing risk,are Cd,As,Hg,Pb,Cu,and Cr.It is noteworthy that only Cd in Lianjiang City demonstrated substantial ecological risk.Other examined heavy metals in other cities of the study area showed slight ecological risk.

Ring finger protein 157 is a prognostic biomarker and is associated with immune infiltrates in human breast cancer

Background: The protein encoded by ring finger protein 157 (RNF157) is known to function as an E3 ubiquitinligase. However, whether the level of RNF157 expression in breast cancer correlates with prognosis and immune cellinfiltration among breast cancer patients remains to be further explored. Methods: In this study, publicly availabledatasets were used for evaluating RNF157 expression in different tumors compared with normal samples. Severalindependent datasets were screened for investigating the relationship between RNF157 and breast cancer survival,different mutation profiles, and tumor immune cell infiltration. We conducted a pathway enrichment analysis toidentify signaling pathways associated with RNF157. Results: Analysis of public and online databases revealed thatRNF157 expression markedly decreased in breast cancer tissue samples compared to non-carcinoma counterparts.Consistently, immunohistochemistry assays also demonstrated this RNF157 down-regulation in breast cancer samples.RNF157 up-regulation could predict the improved survival of breast cancer cases. Further, different RNF157expression level groups exhibited different mutational profiles. Pathway enrichment profiling of RNF157-related genessuggested its possible involvement in regulating breast cancer via the mitogen-activated protein kinase (MAPK)pathway. RNA sequencing (RNA-seq) data and genomic enrichment analysis showed that RNF157 downregulatedseveral genes positively associated with the MAPK signaling pathway. We also explored RNF157 expression andimmune cell infiltration in breast cancer and found that RNF157 mRNA levels were negatively related to non-Timmune cell infiltration. Conclusion: According to our work, RNF157 may be a promising diagnostic biomarker andtherapeutic target for breast cancer.

Evolutionary Plasmonic Properties of Single Truncated Ag Nanowire-on-Au Film Nanocavity

Noble metal nanocavities have been widely demonstrated to possess great potential applications in nanooptics and nanophotonics due to their extraordinary localized surface plasmon resonance.However,most metal nanocrystals synthesized by chemical methods often suffer from truncation with different degrees due to oxidation and dissolution of metal atoms at corner and edges.We investigate the influence of shape truncation on the plasmonic properties of single Ag nanowire on Au film nanocavity using the finite difference time domain method.When the Ag nanowire(the circumradius R_(2)=50 nm)is gradually truncated from pentagonal to circular geometry,the scattering peak position of the nanocavity shows prominent blue shift from 962 nm to 608 nm,suggesting a nonnegligible role of truncation on plasmonic properties.The electric field strength and charge distribution of the structure reveal the evolution from dipole mode to quadrupole mode.It is also found that the plasmon resonance wavelength is linearly dependent on the truncation ratio R_(1)/R_(2)(R_(1) is the inradius)and the modulation slope is also reliable to the size of Ag nanowire.Our observations could shed light on developing high-performance tunable optical nano-devices in future.

Diagnostic performance of texture analysis in the differential diagnosis of perianal fistulising Crohn’s disease and glandular anal fistula

BACKGROUND Perianal fistulising Crohn's disease(PFCD)and glandular anal fistula have many similarities on conventional magnetic resonance imaging.However,many patients with PFCD show concomitant active proctitis,but only few patients with glandular anal fistula have active proctitis.AIM To explore the value of differential diagnosis of PFCD and glandular anal fistula by comparing the textural feature parameters of the rectum and anal canal in fat suppression T2-weighted imaging(FS-T2WI).METHODS Patients with rectal water sac implantation were screened from the first part of this study(48 patients with PFCD and 22 patients with glandular anal fistula).Open-source software ITK-SNAP(Version 3.6.0,http://www.itksnap.org/)was used to delineate the region of interest(ROI)of the entire rectum and anal canal wall on every axial section,and then the ROIs were input in the Analysis Kit software(version V3.0.0.R,GE Healthcare)to calculate the textural feature parameters.Textural feature parameter differences of the rectum and anal canal wall between the PFCD group vs the glandular anal fistula group were analyzed using Mann-Whitney U test.The redundant textural parameters were screened by bivariate Spearman correlation analysis,and binary logistic regression analysis was used to establish the model of textural feature parameters.Finally,diagnostic accuracy was assessed by receiver operating characteristic-area under the curve(AUC)analysis.RESULTS In all,385 textural parameters were obtained,including 37 parameters with statistically significant differences between the PFCD and glandular anal fistula groups.Then,16 texture feature parameters remained after bivariate Spearman correlation analysis,including one histogram parameter(Histogram energy);four grey level co-occurrence matrix(GLCM)parameters(GLCM energy_all direction_offset1_SD,GLCM entropy_all direction_offset4_SD,GLCM entropy_all direction_offset7_SD,and Haralick correlation_all direction_offset7_SD);four texture parameters(Correlation_all direction_offset1_SD,cluster prominence_angle 90_offset4,Inertia_all direction_offset7_SD,and cluster shade_angle 45_offset7);five grey level run-length matrix parameters(grey level nonuniformity_angle 90_offset1,grey level nonuniformity_all direction_offset4_SD,long run high grey level emphasis_all direction_offset1_SD,long run emphasis_all direction_offset4_SD,and long run high grey level emphasis_all direction_offset4_SD);and two form factor parameters(surface area and maximum 3D diameter).The AUC,sensitivity,and specificity of the model of textural feature parameters were 0.917,85.42%,and 86.36%,respectively.CONCLUSION The model of textural feature parameters showed good diagnostic performance for PFCD.The texture feature parameters of the rectum and anal canal in FS-T2WI are helpful to distinguish PFCD from glandular anal fistula.

胰腺钩突部肿瘤行超声内镜引导下针吸活检术的体会

目的分析超声内镜引导下针吸活检术(EUS-FNA)对胰腺钩突部肿瘤的诊断价值。方法回顾性分析13例胰腺钩突部肿瘤患者的临床资料,患者均行EUS-FNA。结果 13例患者中胰腺实质性肿瘤11例,胰腺囊性病变2例;11例实质性肿瘤患者中,获得组织学诊断4例(阳性率36.4%)、细胞学诊断10例(阳性率90.9%),术后并发症包括1例高淀粉酶血症和1例急性水肿性胰腺炎。2例囊性肿瘤患者均获得囊液,行细胞学及肿瘤标记物分析,无术后并发症发生。结论 EUS-FNA用于诊断胰腺钩突部肿瘤是安全有效的,但掌握其技术细节需通过经验的积累。

Curative Effect of 30% Supramolecular Salicylic Acid Combined with Yufa Spray Dressing on Moderate to Severe Scalp Seborrheic Dermatitis

Objective:To observe the clinical efficacy of 30%supramolecular salicylic acid combined with Yufa spray dressing in the treatment of moderate to severe seborrheic dermatitis(seborrheic dermatitis of the scalp,SDS).Methods:From January 2020 to December 2021,150 patients with SDS,who were treated in the Dermatology Clinic of the First Affiliated Hospital of Xi’an Medical University,were randomly divided into two groups,a treatment group and a control group,with 75 cases in each group.The treatment group was given 30%supramolecular salicylic acid combined with Yufa spray dressing on the basis of external medicine given to the control group,while the control group was given oral medicine combined with external medicine.Results:The difference in scores of erythema,scales,pruritus,and folliculitis of the treatment group before and after treatment was significant(P<0.01),indicating that supramolecular salicylic acid combined with Yufa spray dressing can relieve the symptoms of SDS.The difference in scores of erythema of the control group before and after treatment was significant as well(P<0.05),indicating that traditional antibiotics are also effective in treating SDS;however,there was no significant difference(P>0.05)in the scores of other signs and symptoms,such as scales,pruritus,and folliculitis,before and after treatment,indicating that traditional antibiotics have no obvious curative effect on SDS.After 12 weeks of treatment,the improvement in erythema,scaling,and folliculitis was significantly greater in the treatment group compared with the control group(P<0.05).Curative effect comparison showed that the total effective rate of the treatment group was 80.00%,compared with 25.67%of the control group,and the difference was statistically significant(P<0.05).Conclusion:30%supramolecular salicylic acid combined with Yufa spray dressing can significantly improve the therapeutic effect in moderate to severe SDS;the recurrence rate is lower,the course of treatment is shorted,and patients generally feel better;thus,it is a new option for the treatment of dermatitis.

Management of bile duct injuries combined with accessory hepatic duct during laparoscopic cholecystectomy

Bile duct injuries(BDIs)are difficult to avoid absolutely when the biliary tract has a malformation,such as accessory hepatic duct.Here,we investigated the management strategies for BDI combined with accessory hepatic duct during laparoscopic cholecystectomy.

Complete duodenal obstruction induced by groove pancreatitis: A case report

BACKGROUND Groove pancreatitis(GP)is a type of chronic pancreatitis occurring in an anatomic area between the duodenum,head of the pancreas,and common bile duct.Duodenal obstruction is always caused by malignant pancreatic diseases,such as pancreatic head carcinoma,while is rarely induced by benign pancreatic diseases,such as pancreatitis.CASE SUMMARY A 39-year-old man presented with a 1-mo history of upper abdominal discomfort.His concomitant symptoms were abdominal distension,postprandial nausea,and vomiting.Contrast-enhanced computed tomography of the abdomen showed thickening of the intestinal wall with enhancement of the descending segment of the duodenum,which could not be clearly differentiated from the head of the pancreas.Upper gastrointestinal radiographs and gastrointestinal endoscopy showed a complete obstruction of the descending duodenum.An operation found that a 3-cm mass was located in the“groove part”of the pancreas and oppressing the descending duodenum.Pancreaticoduodenectomy was performed to relieve the obstruction and thoroughly remove the pancreatic lesions.The pathologic diagnosis was pancreatitis.The patient had an uneventful recovery with no complications.CONCLUSION Because of the special location and the contracture induced by long-term chronic inflammation,our case reminds surgeons that some benign pancreatic diseases,such as GP,can also present with symptoms similar to those of pancreatic cancer.This knowledge can help to avoid an unnecessary radical operation.

Microbial and metabolomic mechanisms mediating the effects of dietary inulin and cellulose supplementation on porcine oocyte and uterine development

Background:Dietary fiber(DF)is often eschewed in swine diet due to its anti-nutritional effects,but DF is attracting growing attention for its reproductive benefits.The objective of this study was to investigate the effects of DF intake level on oocyte maturation and uterine development,to determine the optimal DF intake for gilts,and gain microbial and metabolomic insight into the underlying mechanisms involved.Methods:Seventy-six Landrace×Yorkshire(LY)crossbred replacement gilts of similar age(92.6±0.6 d;mean±standard deviation[SD])and body weight(BW,33.8±3.9 kg;mean±SD)were randomly allocated to 4 dietary treatment groups(n=19);a basal diet without extra DF intake(DF 1.0),and 3 dietary groups ingesting an extra50%(DF 1.5),75%(DF 1.75),and 100%(DF 2.0)dietary fiber mixture consisting of inulin and cellulose(1:4).Oocyte maturation and uterine development were assessed on 19 d of the 2nd oestrous cycle.Microbial diversity of faecal samples was analysed by high-throughput pyrosequencing(16S r RNA)and blood samples were subjected to untargeted metabolomics.Results:The rates of oocytes showing first polar bodies after in vitro maturation for 44 h and uterine development increased linearly with increasing DF intake;DF 1.75 gilts had a 19.8%faster oocyte maturation rate and a 48.9 cm longer uterus than DF 1.0 gilts(P<0.05).Among the top 10 microbiota components at the phylum level,8increased linearly with increasing DF level,and the relative abundance of 30 of 53 microbiota components at the genus level(>0.1%)increased linearly or quadratically with increasing DF intake.Untargeted metabolic analysis revealed significant changes in serum metabolites that were closely associated with microbiota,including serotonin,a gut-derived signal that stimulates oocyte maturation.Conclusions:The findings provide evidence of the benefits of increased DF intake by supplementing inulin and cellulose on oocyte maturation and uterine development in gilts,and new microbial and metabolomic insight into the mechanisms mediating the effects of DF on reproductive performance of replacement gilts.

Nitrogen and Boron Co-Doped Carbon Nanotubes Embedded with Nickel Nanoparticles as Highly Efficient Electromagnetic Wave Absorbing Materials

Due to the limitations of impedance matching and attenuation matching,carbon nanotubes(CNTs)employed alone have a weak capacity to attenuate electromagnetic wave(EMW)energy.In this work,B and N co-doped CNTs with embedded Ni nanoparticles(Ni@BNCNTs)are fabricated via an in situ doping method.Compared with a sample without B doping,Ni@BNCNTs demonstrate a superior EMW absorption performance,with all minimum reflection loss values below−20 dB,even at a matching thickness of 1.5 mm.The experimental and theoretical calculation results demonstrate that B doping increases conduction and polarization relaxation losses,as well as the impedance matching characteristic,which is responsible for the enhanced EMW absorption performance of Ni@BNCNTs.

High-Quality InSb Grown on Semi-Insulting GaAs Substrates by Metalorganic Chemical Vapor Deposition for Hall Sensor Application

High-quality InSb epilayers are grown on semi-insulting GaAs substrates by metalorganic chemical vapor deposition using an indium pre-deposition technique. The influence of Ⅴ/Ⅲ ratio and indium pre-deposition time on the surface morphology, crystalline quality and electrical properties of the InSb epilayer is systematically investigated using Nomarski microscopy, atomic force microscopy, high-resolution x-ray diffraction, Hall measurement and contactless sheet resistance measurement. It is found that a 2-μm-thick InSb epilayer grown at 450℃ with a Ⅴ/Ⅲ ratio of 5 and an indium pre-deposition time of 2.5s exhibits the optimum material quality, with a root-meansquare surface roughness of only 1.2 nm, an XRD rocking curve with full width at half maximum of 358 arcsec and a room-temperature electron mobility of 4.6 × 10~4 cm^2/V·s. These values are comparable with those grown by molecular beam epitaxy. Hall sensors are fabricated utilizing a 600-nm-thick InSb epilayer. The output Hall voltages of these sensors exceed 10 mV with the input voltage of 1 V at 9.3 mT and the electron mobility of 3.2 × 10~4 cm^2/V·s is determined, which indicates a strong potential for Hall applications.

MicroRNA signature in response to nutrient restriction and re-feeding in fast skeletal muscle of grass carp （Ctenopharyngodon idella）

The grass carp(Ctenopharyngodon idella) is one of the most important cultivated fish species in China.Mounting evidences suggests that microRNAs(miRNAs) may be key regulators of skeletal muscle among the grass carp,but the knowledge of the identity of myogenic miRNAs and role of miRNAs during skeletal muscle anabolic state remains limited.In the present study,we choose 8 miRNAs previously reported to act as muscle growth-related miRNAs for fasting-refeeding research.We investigated postprandial changes in the expression of 8 miRNAs following a single satiating meal in grass carp juveniles who had been fasting for one week and found that 7 miRNAs were sharply up-regulated within 1 or 3 h after refeeding,suggesting that they may be promising candidate miRNAs involved in a fast-response signaling system that regulates fish skeletal muscle growth.

Resection of recurrent third branchial cleft fistulas assisted by flexible pharyngotomy

BACKGROUND Treatment of fistulas arising from the third branchial cleft includes endoscopic cauterization or open cervical fistulectomy.Both approaches are associated with recurrence rates of 14%-18%,and possibly greater rates when the fistula has been treated operatively beforehand.Treatment of fistulas arising from the third branchial cleft is associated with an inordinate recurrence rate.Recurrence may be multifactorial and related to incomplete resection of all of the anatomical elements of the fistula.AIM To present a new approach that involves complete resection of the recurrent fistula by a combined therapeutic approach.METHODS Here,12 adult patients diagnosed with recurrent third branchial cleft fistulas underwent a combined therapy assisted by flexible fiber-optic pharyngoscopy to identify and resect the entry site of the fistula into the pyriform sinus.The fistulous opening into the pyriform sinus was identified by flexible fiber-optic pharyngoscopy.The application of intubation with a guidewire by pharyngoscopy,in addition to the removal of the partial excision of the thyroid cartilage,allowed complete resection of the opening and all parts of the fistula tract.RESULTS All of the internal openings of the fistulas in the pharynx were found and easily identified by flexible fiber-optic pharyngoscopy.All of the 12 patients underwent complete resection of the recurrent fistula by the combined therapeutic approach.There were no postoperative complications such as parapharyngeal abscess or wound infection,injury or dysfunction of the recurrent laryngeal or superior laryngeal nerves.The pharyngeal edema had degraded,and the pharyngeal wound healed postoperatively within 1 wk.Laryngeal endoscopy and voice analysis were performed on the 14th d post-operatively.Vocal cord movements did not change.The characters of voice for jitter,shimmer,and normalized noise energy were all within normal limits.In addition,no recurrences were observed during the 13-60 mo follow-up period.CONCLUSION It can be concluded that the proposed combined therapy is associated with excellent results,minimal morbidity,and no recurrence.

High-speed all-optic optical coherence tomography and photoacoustic microscopy dual-modal system for microcirculation evaluation

We propose a high-speed all-optic dual-modal system that integrates spectral domain optical coherence tomography and photoacoustic microscopy(PAM).A 3*3 coupler-based interfer-ometer is used to remotely detect the surface vibration caused by photoacoustic(PA)waves.Three outputs of the interferometer are acquired simultaneously with a multi-channel data ac-quisition card.One channel data with the highest PA signal detection sensitivity is selected for sensitivity compensation.Experiment on the phantom demonstrates that the proposed method can sucessfully compensate for the loss of intensity caused by sensitivity variation.The imaging speed of the PAM is improved compared to our previous system.The total time to image a sample with 256×256 pixels is~20s.Using the proposed system,the microvasculature in the mouse auricle is visualized and the blood flow state is accessed.

Magnetic resonance imaging findings of carcinoma arising from anal fistula: A retrospective study in a single institution

BACKGROUND Magnetic resonance imaging(MRI)is currently the standard investigation for suspected perianal diseases.Carcinoma arising from anal fistula is very rare,and early diagnosis is often difficult.AIM To describe and summarize the MRI findings of carcinoma arising from anal fistula.METHODS In this retrospective study,records of ten patients diagnosed with carcinoma arising from anal fistula and confirmed by surgery(n=7)or biopsy(n=3)between June 2006 and August 2018 were analyzed.All patients underwent preoperative pelvic MRI.Morphologic features,signal characteristics,fistula between the mass and the anus,contrast enhancement of mass,signal and enhancement of peritumoral areas,and regional lymphadenopathy were assessed.RESULTS All ten tumors were solitary(8 mucinous adenocarcinomas and 2 adenocarcinomas).The maximum diameter of the tumors ranged from 3.4 cm to 12.4 cm(median:4.15 cm;mean:5.68 cm).Eight patients had a fistula between the mass and the anus.Contrast enhancement of the peritumoral areas was noted in three(3/5)patients.Perirectal or inguinal lymphadenopathy was noted in seven patients.Most lesions of mucinous adenocarcinoma were multiloculated and cauliflower-like,with a thin capsule and focally unclear boundary.They were markedly hyperintense on fat-suppressed T2WI,slightly hyperintense with focal hyperintensity on diffusion-weighted imaging(DWI),and hyperintense with focal hypointensity on apparent diffusion coefficient(ADC)map,with progressive mesh-like contrast enhancement.Adenocarcinomas had an infiltrative margin without a capsule and appeared heterogeneously hyperintense or slightly hyperintense on fat-suppressed T2WI,hyperintense on DWI,and hypointense on ADC map,with persistent heterogeneous enhancement.CONCLUSION Our study highlighted several characteristic and potentially helpful MRI findings to diagnose carcinomas arising from anal fistula.

Collision-aware interactive simulation using graph neural networks

Deep simulations have gained widespread attention owing to their excellent acceleration performances.However,these methods cannot provide effective collision detection and response strategies.We propose a deep interac-tive physical simulation framework that can effectively address tool-object collisions.The framework can predict the dynamic information by considering the collision state.In particular,the graph neural network is chosen as the base model,and a collision-aware recursive regression module is introduced to update the network parameters recursively using interpenetration distances calculated from the vertex-face and edge-edge tests.Additionally,a novel self-supervised collision term is introduced to provide a more compact collision response.This study extensively evaluates the proposed method and shows that it effectively reduces interpenetration artifacts while ensuring high simulation efficiency.

Severe hematuria due to vesical varices in a patient with portal hypertension:A case report

BACKGROUND Hematuria is one of the most common clinical symptoms for urologists and is typically observed in urinary system tumors,prostate hyperplasia,and urinary stone disease.Hematuria due to vesical varices is very rare,and only a few cases have been reported since 1989.We report the first case of vesical varices due to portal hypertension with aberrant development and functioning of the genitourinary system along with the complete diagnosis and treatment process.CASE SUMMARY This patient was a 53-year-old man with a history of aberrant development of the genitourinary system and hepatitis B-associated cirrhosis.He was admitted to the emergency department with severe hematuria and bladder clot tamponade.Many abnormally dilated blood vessels were found surrounding the bladder in the pelvis by color Doppler ultrasound,contrast-enhanced computed tomography,and three-dimensional visualization technology.It was difficult to perform transurethral cystoscopy and hemostasis in this patient,so we performed open surgical bladder exploration for hemostasis and surgical devascularization around the bladder.CONCLUSION Urologists should improve the understanding of the pathophysiology,clinical manifestations,diagnosis,and treatment of vesical varices.This case may be presented as a reference for the diagnosis and management of severe hematuria due to vesical varices.

FMT:A Potential Therapeutic and Rehabilitative Intervention for COVID-19

Coronavirus disease 2019(COVID-19),which was outbreak in December 2019 Wuhan,China,has spread to more than 100 countries.In addition to respiratory symptoms,COVID-19 can also cause some digestive symptoms such as nausea and diarrhea.As a variety of respiratory diseases which are associated with a dysbiosis in both airway microbiota and the intestinal microbiota,COVID-19 may cause digestive symptoms through a constant cross-talk between the system which is known as the Gut_Lung Axis.Additionally,lymphopenia and hypercytokinemia were also common in COVID-19 patients which suggest that COVID-19 could compromise the immune system.Given the fact that gut microbiota not only could maintain immune homeostasis and immune responses at local mucosal surfaces,but also has distal protective effects and protect against respiratory virus.FMT is an effective way to enhance immunity and would be a potential therapy for individuals with viral infection.However,currently no direct clinical evidence proved that modulation of gut microbiota has the therapeutic role in treatment of COVID-19,from the perspective of microbiota and immunity after viral infection,we speculate that targeting gut microbiota might be a new therapeutic option or at least adjuvant therapeutic choice.In this Personal View,we describe the five aspects:COVID-19 and compromised immunity system,Microbiota,immune system and viral infection,FMT,immunity and virus infection,potential application of FMT in the treatment of COVID-19.

Effect of cerium on microstructure,eutectic carbides and Laves phase in electroslag remelted 15Cr-22Ni-1Nb austenitic heat-resistant steel

The dendrites,eutectic carbides,Laves phase and microsegregation of alloying element in electroslag remelted 15Cr-22Ni-1Nb austenitic heat-resistant steel with varying cerium contents were studied.The liquidus and solidus temperatures of the steel were determined to reveal the effect of cerium on solidification temperature interval and local solidification time of the steel.The secondary dendrite arm spacing decreases from 57.10 to 40.18μm with increasing the cerium content from 0 to 0.0630 wt.%.The eutectic NbC and Laves phase in as-cast ingots exhibit blocky and honeycomb morphology,respectively.The area fractions and sizes of eutectic NbC and Laves phase in as-cast ingots decrease with the increase in cerium content.The atomic percentage of Laves phase-forming element(Ni,Nb,Cr,Mo and Si)decreases with the increase in cerium content of the steel.The microsegregation of Mo,Ni,Si,Cr and Nb decreases with increasing the cerium content,which is favorable to reducing both the amount and sizes of eutectic NbC and Laves phase in as-cast ingots.The solidification temperature interval and local solidification time of the steel decrease as the cerium content is increased from 0 to 0.0630 wt.%,which inhibits the growth of dendrites,eutectic NbC and Laves phase.