Identification of Stability Domains for Flow Parameters in Fused Filament Fabrication Using Acoustic Emission

In Fused Filament Fabrication(FFF),the state of material flow significantly influences printing outcomes.However,online monitoring of these micro-physical processes within the extruder remains challenging.The flow state is affected by multiple parameters,with temperature and volumetric flow rate(VFR)being the most critical.The study explores the stable extrusion of flow with a highly sensitive acoustic emission(AE)sensor so that AE signals generated by the friction in the annular region can reflect the flow state more effectively.Nevertheless,the large volume and broad frequency range of the data present processing challenges.This study proposes a method that initially selects short impact signals and then uses the Fast Kurtogram(FK)to identify the frequency with the highest kurtosis for signal filtration.The results indicate that this approach significantly enhances processing speed and improves feature extraction capabilities.By correlating AE characteristics under various parameters with the quality of extruded raster beads,AE can monitor the real-time state of material flow.This study offers a concise and efficient method for monitoring the state of raster beads and demonstrates the potential of online monitoring of the flow states.

Two-dimensional Cr_(2)Cl_(3)S_(3)Janus magnetic semiconductor with large magnetic exchange interaction and high-T_(C)

The two-dimensional(2D)Janus monolayers are promising in spintronic device application due to their enhanced magnetic couplings and Curie temperatures.Van der Waals CrCl_(3) monolayer has been experimentally proved to have an in-plane magnetic easy axis and a low Curie temperature of 17 K,which will limit its application in spintronic devices.In this work,we propose a new Janus monolayer Cr_(2)Cl_(3)S_(3) based on the first principles calculations.The phonon dispersion and elastic constants confirm that Janus monolayer Cr_(2)Cl_(3)S_(3) is dynamically and mechanically stable.Our Monte Carlo simulation results based on magnetic exchange constants reveal that Janus monolayer Cr_(2)Cl_(3)S_(3) is an intrinsic ferromagnetic semiconductor with TC of 180 K,which is much higher than that of CrCl_(3) due to the enhanced ferromagnetic coupling caused by S substitution.Moreover,the magnetic easy axis of Janus Cr_(2)Cl_(3)S_(3) can be tuned to the perpendicular direction with a large magnetic anisotropy energy(MAE)of 142eV/Cr.Furthermore,the effect of biaxial strain on the magnetic property of Janus monolayer Cr_(2)Cl_(3)S_(3) is evaluated.It is found that the Curie temperature is more robust under tensile strain.This work indicates that the Janus monolayer Cr_(2)Cl_(3)S_(3) presents increased Curie temperature and out-of-plane magnetic easy axis,suggesting greater application potential in 2D spintronic devices.

聚苯乙烯微塑料对球形棕囊藻生长的影响

【目的】探究聚苯乙烯微塑料对球形棕囊藻(Phaeocystis globosa)生长的影响,为微塑料和致灾赤潮藻复合污染的生态效应以及海洋生态系统保护研究提供科学依据。【方法】在以f/2培养基为培养介质、初始密度为2000 mL^(-1)的球形棕囊藻藻液中添加小粒径(直径0.1、1.0μm)及大粒径(直径10.0、100.0、1000.0μm)聚苯乙烯微塑料,扩大培养30 d,分析不同粒径微塑料对球形棕囊藻单细胞密度、囊体数量、囊体直径以及囊体细胞密度的影响。【结果】微塑料对球形棕囊藻游离单细胞生长有明显的抑制作用(P<0.05);大粒径微塑料的抑制作用较强,10.0μm组和1000.0μm组的抑制率最高分别为99.3%及99.2%。微塑料可使实验组囊体数量显著低于对照组(P<0.05),大粒径微塑料对囊体数量的抑制率均在94.0%以上,并延缓囊体的形成时间。微塑料对球形棕囊藻囊体直径的增大有显著促进作用(P<0.05);大粒径微塑料对囊体直径增长率最高分别达到2633.4%(30 d)、2515.1%(27 d)及1868.2%(27 d)。微塑料对球形棕囊藻囊体细胞的生长有明显的促进作用(P<0.05),小粒径微塑料的促进作用明显大于大粒径微塑料,培养至30 d,0.1、1.0μm组囊体单细胞密度增长率已分别达到52249.4%、47666.3%。【结论】聚苯乙烯塑料微球可抑制球形棕囊藻游离单细胞的生长,延迟球形棕囊藻形成囊体的时间,减少囊体数量,增加囊体直径,增加囊体细胞密度。大粒径(10.0、100.0、1000.0μm)微塑料对游离单细胞密度、囊体数量、囊体直径影响较大,而小粒径(0.1、1.0μm)微塑料则对囊体细胞的生长有更加明显的促进作用。

Tenofovir amibufenamide vs tenofovir alafenamide for treating chronic hepatitis B:A real-world study

BACKGROUND The efficacy and safety profile of tenofovir amibufenamide(TMF)in chronic hepatitis B(CHB)patients is not well-established.AIM To compare the efficacy and safety of TMF and tenofovir alafenamide(TAF)over a 48-wk period in patients with CHB.METHODS A total of 215 subjects meeting the inclusion criteria were enrolled and divided into two groups:TMF group(n=106)and the TAF group(n=109).The study included a comparison of virological response(VR):Undetectable hepatitis B virus DNA levels,alanine transaminase(ALT)normalization rates,renal function parameters,and blood lipid profiles.RESULTS At 24 and 48 wk,VR rates for the TMF group were 53.57%and 78.57%,respectively,compared with 48.31%and 78.65%for the TAF group(P>0.05).The VR rates were also similar in both groups among patients with low-level viremia,both hepatitis B e antigen(HBeAg)-positive and HBeAg-negative subgroups.The TMF cohort showed ALT normalization and renal safety profiles similar to the TAF group.There was a notable increase in total cholesterol levels in the TAF group(P=0.045),which was not observed in the TMF group(P>0.05).In patients with liver cirrhosis,both groups exhibited comparable VR and ALT normalization rates and renal safety profiles.However,the fibrosis 4 score at 48 wk showed a significant reduction in the TAF group as compared to the TMF group within the liver cirrhosis subgroup.CONCLUSION Our study found TMF is as effective as TAF in treating CHB and has a comparable safety profile.However,TAF may be associated with worsening lipid profiles.

Load-forecasting method for IES based on LSTM and dynamic similar days with multi-features

To fully exploit the rich characteristic variation laws of an integrated energy system(IES)and further improve the short-term load-forecasting accuracy,a load-forecasting method is proposed for an IES based on LSTM and dynamic similar days with multi-features.Feature expansion was performed to construct a comprehensive load day covering the load and meteorological information with coarse and fine time granularity,far and near time periods.The Gaussian mixture model(GMM)was used to divide the scene of the comprehensive load day,and gray correlation analysis was used to match the scene with the coarse time granularity characteristics of the day to be forecasted.Five typical days with the highest correlation with the day to be predicted in the scene were selected to construct a“dynamic similar day”by weighting.The key features of adjacent days and dynamic similar days were used to forecast multi-loads with fine time granularity using LSTM.Comparing the static features as input and the selection method of similar days based on non-extended single features,the effectiveness of the proposed prediction method was verified.

Simulating the strong ground motion of the 2022 MS6.8 Luding,Sichuan,China Earthquake

Stochastic finite-fault simulations are effective for simulating ground motions and are widely used in engineering to determine the impacts of ground motion and develop relevant predictive equations.In this study,the source,path,and site amplification coefficient of western Sichuan Province,China,and stochastic finite-fault simulations were used to simulate the acceleration time series,Fourier amplitude spectra,and 5%damped response spectra of 28 strong-motion stations with rupture distances within 300 km of the 2022 MS6.8 Luding earthquake.The simulation results of 14 stations at rupture distances of 45-185 km match the observation.However,the simulation results of 3 near-and 6 far-field stations at rupture distances of 12-36 km and 222-286 km,respectively,were obviously deviated from the observations.Simulation results of the near-field stations are larger than the observations at high frequencies(>6 Hz).The discrepancy likely comes from the nonlinear site effect of near-field stations,which reduced the site amplification at high frequencies.Simulation result of the far-field stations is smaller than the observation at frequencies above 1 Hz.As these stations are located close to the Longmenshan Fault Zone(LFZ),thus,we obtained a new quality factor(Q)from data of historical events and stations located around LFZ.Using the new Q value,the discrepancies of the high-frequency simulation results of the far-field stations were corrected.This result indicated that the laterally varying Q values can be used to address the impact of strong crustal lateral heterogeneity on simulation.

Tuning exsolution of nanoparticles in defect engineered layered perovskite oxides for efficient CO_(2) electrolysis

Solid oxide electrolysis cell(SOEC) could be a potential technology to afford chemical storage of renewable electricity by converting water and carbon dioxide.In this work,we present the Ni-doped layered perovskite oxides,(La_(4)Sr_(n-4))_(0.9)Ti_(0.9n)Ni_(0.1n)O_(3n+2) with n=5,8,and 12(LSTNn) for application as catalysts of CO_(2) electrolysis with the exsolution of Ni nanoparticles through a simple in-situ growth method.It is found that the density,size,and distribution of exsolved Ni nanoparticles are determined by the number of n in LSTNn due to the different stack structures of TiO_6 octahedra along the c axis.The Ni doping in LSTNn significantly improved the electrochemical activity by increasing oxygen vacancies,and the Ni metallic nanoparticles afford much more active sites.The results show that LSTNn cathodes can successfully be manipulated the activity by controlling both the n number and Ni exsolution.Among these LSTNn(n=5,8,and 12),LSTN8 renders a higher activity for electrolysis of CO_(2) with a current density of 1.50A cm^(-2)@2.0 V at 800℃ It is clear from these results that the number of n in(La_(4)Sr_(n-4))_(0.9)Ti_(0.9n)Ni_(0.1n)O_(3n+2)with Ni-doping is a key factor in controlling the electrochemical performance and catalytic activity in SOEC.

Fibula allograft transplantation combined with locking plate for treatment of recurrent monostotic fibular fibrous dysplasia:A case report

BACKGROUND Fibrous dysplasia is a congenital disorder in which normal bone is replaced by fibro-osseous tissue or irregular trabeculae of woven bone intermixed with mature collagenous tissue.A single or multiple bones are affected.This rare bone disorder has three clinical patterns including monostotic,polyostotic,and that associated with McCune-Albright syndrome.Most studies report primary fibrous dysplasia.However,a few cases of recurrent monostotic fibular fibrous dysplasia have been reported.Here,we report a therapeutic strategy for recurrent fibular fibrous dysplasia.CASE SUMMARY A 4-year-old boy was admitted for persistent pain in the left lower limb and abnormal gait over the previous 9 mo.He had no history of present or past illness.Preoperative imaging data showed erosion-like changes with bone expansion of the left middle and lower fibular segment.Tumor tissue in the fibular bone marrow cavity was removed by curettage,and rapid intraoperative pathological examination suggested fibular fibrous dysplasia.An allograft was implanted into the fibular medullary cavity.However,he was readmitted with clinical symptoms including persistent pain,abnormal gait,and local swelling at the age of 6 years.He was diagnosed with recurrent fibular fibrous dysplasia based on the second medical examination.He underwent fibular bone tumor radical resection and longus fibular allograft transplantation combined with fibular bone locking plate and screws.Good host bone to allogenic bone graft fusion was observed by the physician on postoperative regular follow-up.CONCLUSION Radical resection of fibrous dysplasia and longus fibula allograft combined with internal fixation for reconstruction are suitable for the treatment of recurrent monostotic fibular fibrous dysplasia.

双重血浆分子吸附治疗肝衰竭的临床研究

目的评价双重血浆分子吸附(DPMAS)治疗肝衰竭的疗效及安全性。方法回顾性分析68例肝衰竭患者的病例资料,根据其治疗方式不同分为DPMAS组(内科治疗联合DPMAS,39例)和对照组(内科治疗组,29例);分析两组患者治疗前后的临床症状、体征以及血常规、肝肾功能、凝血功能等生化指标,比较分析两组患者的总体疗效、不同病情分期和不同并发症的有效率,记录相关的副作用。结果与对照组相比,DPMAS组患者的临床症状好转,总体有效率提高,差异有统计学意义(P<0.05)。DPMAS可有效改善早期肝衰竭的预后,但对中晚期肝衰竭,疗效不显著,与对照组相比,二者差异无统计学意义(P>0.05)。所有经DPMAS治疗的患者,未发生电解质紊乱、出血等不良事件,副作用以轻度血压下降为主要表现。结论 DPMAS可改善肝衰竭患者的临床症状,提高治疗的有效率,尤其对早期肝衰竭治疗效果较好,且无明显副作用,是一种安全有效的人工肝治疗方法。

杂化纳米HNTs-d-RGO/聚乳酸复合材料的制备及热性能

以埃洛石纳米管(HNTs)和氧化石墨烯(GO)为增强填料,聚乳酸(PLA)为基体,利用硅烷偶联剂KH550(APTES)将HNTs与GO杂化获得HNTs-d-RGO纳米粒子,再通过熔融挤出热拉-骤冷工艺制备了一系列纳米HNTs-d-RGO/PLA复合材料。分别采用透射电镜、红外光谱、扫描电镜、X射线衍射、差示扫描量热分析和维卡软化仪研究了纳米HNTs-d-RGO/PLA复合材料的微观形态、结晶性能与热性能。结果表明,与GO的结晶衍射峰相比,杂化HNTs-d-RGO相应的特征衍射峰强度明显减弱;与纯PLA相比,当HNTs-d-RGO含量达到5%时,其结晶度和耐热变形温度较纯PLA分别提高了19.3%和54.3℃,当HNTs-d-RGO含量达到7%后,纳米HNTs-d-RGO/PLA复合材料团聚现象明显,而相应的结晶度和耐热变形温度出现了一定程度的下降。

石墨烯材料制备技术研究进展

石墨烯是二维晶体结构的碳纳米材料,其具有优异的导电、导热、光学和力学特性引起了研究者的浓厚兴趣,在材料、电子、物理、化学、能源、生物医药等众多领域具有广阔的应用前景。本文详细综述了近年来国内外参考文献对于石墨烯制备方法的研究,并指出了目前各种石墨烯制备方法中存在的问题。最后,本文对石墨烯制备方法的改进方向进行了展望。

涠洲岛海域营养盐变化特征与评价

本研究拟分析涠洲岛海域水体的营养盐成分、比例、浓度以及时空变化,掌握该海域的营养状况与变化趋势,并对海域生态进行健康评价。实验采集海域水体样品并测定其硝酸盐、亚硝酸盐、铵盐、磷酸盐、硅酸盐含量及化学需氧量等,采用单项标准指数法与富营养化指数法进行分析评价。调查结果显示:溶解无机氮浓度为14-250μg/L,平均为96μg/L;活性磷酸盐浓度为2.8-38μg/L,平均为15μg/L;活性硅酸盐浓度变化不大,为125-280μg/L,平均为193μg/L。活性磷酸盐与溶解无机氮季节浓度变化较大,时间上,活性磷酸盐在秋季达到变化高峰,溶解无机氮在夏季达到变化高峰;空间上,各营养盐整体呈现由西南向东北递增的趋势,位于涠洲岛东面的海域营养因子浓度较高。根据富营养化指数法得出年际海水富营养化指数为0.016-0.26,均值为0.090,属贫营养海水。其中春季富营养化指数最高,为0.26;冬季富营养化指数最低,为0.016。因此,涠洲岛近岸海域水环境质量现状整体为良好。

涠洲岛西面及西南面沉积物重金属污染分析

【目的】研究广西涠洲岛海域沉积物污染情况并进行分析与评价。【方法】通过分析2014年涠洲岛沉积物重金属元素Cu、Pb、Zn、Cd、Cr含量水平,运用单因子评价法、潜在生态风险指数法和地累积指数法进行污染程度评价。【结果】涠洲岛西面及西南面海域沉积物重金属含量均值从小到大依次为Cd<Cu<Pb<Cr<Zn,分别对应未检出、3.02 mg·kg^(-1)、3.19 mg·kg^(-1)、6.47 mg·kg^(-1)、10.10 mg·kg^(-1),含量范围分别为未检出、0.95~8.29mg·kg^(-1)、2.68~4.07mg·kg^(-1)、1.81~18.46mg·kg^(-1)、ND^34.59mg·kg^(-1)。重金属污染程度属于"低水平",单个及多种重金属生态风险分级均为"轻微",其中Cu是引发生态风险的主要元素,地累积指数亦表明该海域各重金属污染程度均为0级。【结论】总体来说,涠洲岛西面及西南面海域沉积物重金属含量与污染程度较广西沿海其他海域低,仍属清洁水平。

涠洲岛近岸海域重金属污染状况研究

为了解涠洲岛近岸海域重金属元素Cu、Pb、Zn、Cd、Cr和Hg的污染现状,分别于2018年9月和2019年3月在涠洲岛近岸海域采集水样和生物样品,对其重金属含量进行分析,并计算各重金属的单项污染指数及其生物富集系数。结果显示,春季涠洲岛近岸海域的海水重金属含量均值排序为Zn>Pb>Cu>Cr>Cd>Hg,浓度为0.00-7.30μg/L;秋季为Cu>Pb>Cd>Hg>Cr=Zn,浓度为0.00-4.18μg/L。整体来看,秋季涠洲岛近岸海域的海水各重金属含量均在国家一类海水水质标准范围内,但春季涠洲岛东南面和北面的站点存在Pb超标现象。单项污染指数的计算结果表明,春季海水重金属污染严重程度依次为Pb>Hg>Zn>Cu>Cd>Cr,秋季为Pb>Cu>Hg>Zn>Cd>Cr,均未超出国家一类海水水质标准。春季海洋生物重金属含量均值排序为Zn>Cr>Cu>Hg>Pb>Cd,秋季为Zn>Cu>Cr>Hg>Pb>Cd。除Hg、Zn、Cr外,各重金属富集指数均未超过1000,Hg、Zn、Cr在当地海洋生物体内存在比较明显的富集累积现象,其中Hg的富集程度显著高于其他重金属。总体来看,涠洲岛近岸海域水质状况良好,海洋生物受重金属污染程度低,均未超出国家水质及食品安全标准,但Hg、Zn、Cr出现了一定的生物富集现象,需要警惕。

广西北部湾近岸海域营养盐与富营养化状态研究

为全面了解广西北部湾近岸海域营养盐与富营养化程度,于2021年8月和2022年1月在珍珠湾、钦州湾、廉州湾、铁山港和涠洲岛海域共27个站位采集表层水,分析营养盐浓度,并运用营养盐限制因素评价方法和富营养化指数法分析营养盐结构特征和富营养化状况。结果表明:广西北部湾近岸海域夏季表层水体溶解态无机氮(DIN)、磷酸盐(PO_(4)^(3-)-P)和硅酸盐(SiO_(3)^(2-)-Si)均值分别为0.177 mg/L、0.019 mg/L和0.578 mg/L,冬季三者分别为0.162 mg/L、0.021 mg/L和0.324 mg/L,营养盐浓度均为SiO_(3)^(2-)-Si>DIN>PO_(4)^(3-)-P;其中DIN和SiO_(3)^(2-)-Si平均值在夏季高于冬季,而PO_(4)^(3-)-P为夏季略低于冬季。各海湾营养盐浓度大小依次为铁山港和钦州湾>廉州湾>珍珠湾>涠洲岛,且在4个海湾均呈湾内向湾外递减的空间变化趋势。夏季氮磷摩尔比(N/P)、硅氮摩尔比(Si/N)和硅磷摩尔比(Si/P)分别为4.3-35.2,0.5-6.5和12.0-139.9,对应均值分别为19.6,2.0和35.5,以潜在磷(P)限制为主,占所有站位的29.6%;氮(N)限制占14.8%,其余站位无营养盐限制的情况。冬季N/P、Si/N和Si/P分别为4.3-36.2,0.8-2.0和8.4-37.1,对应均值分别为20.4,1.1和21.5,以潜在P限制为主,占所有站位的36.4%;N限制占9.1%。夏季富营养化指数E为0.04-3.92,平均值为1.13;冬季富营养化指数E为0.03-3.68,平均值为1.08,夏季富营养化程度略高于冬季。总的来说,北部湾近岸铁山港富营养化程度最高,其次为钦州湾,两者绝大部分海域均已达到中度富营养,廉州湾30.0%海域达到轻度富营养,而珍珠湾和涠洲岛均属于贫营养。本研究结果可为北部湾海洋环境保护和海水养殖提供基础数据。

2021年秋季广西廉州湾海域营养盐及水质状况分析

2021年10月(秋季)对廉州湾近岸海域进行现场调查,分析廉州湾营养盐的分布特征,并利用富营养化指数和有机污染指数对该海域海水水质进行等级划分与评价。结果显示:秋季廉州湾海域的溶解态无机氮(DIN)浓度为0.149-1.587 mg/L,均值为0.493 mg/L;溶解态无机磷(DIP)浓度为0.010-0.084 mg/L,均值为0.033 mg/L;化学需氧量(COD)浓度为0.89-3.27 mg/L,均值为1.47 mg/L。DIN呈现近岸高、中部低的分布;DIP由湾内至湾外呈递减趋势,梯度分布明显,受河流输入影响显著。调查区域的富营养化指数为0.48-76.25,均值为12.23,大多数站位的水质状况属于轻度至中度富营养水平,严重富营养化主要出现在南流江口附近的站位;有机污染指数为-0.15-7.20,均值为1.80,研究区域50%的水质受到不同程度污染,南流江水质污染最严重,属于严重污染水域。总体来看,河流输入的陆源污染和人类对廉州湾海域的开发利用,是廉州湾海域富营养化和有机污染程度高的主要原因。

Serum levels of mi RNA in patients with hepatitis B virus-associated acute-on-chronic liver failure

Background: Hepatitis B virus(HBV)-associated acute-on-chronic liver failure(HBV-ACLF) is a lifethreatening condition and its exact pathophysiology and progression remain unclear. The present study aimed to assess the role of serum mi RNAs in the evaluation of HBV-ACLF and to develop a model to predict the outcomes for ACLF.Methods: Serum was collected from 41 chronic hepatitis B and 55 HBV-ACLF patients in addition to30 chronic asymptomatic HBV carriers as controls. The mi RNAs expressions were measured by real-time quantitative PCR(q-PCR). Statistical analyses were conducted to assess the ability of differentially expressed mi RNAs and other prognostic factors in identifying ACLF prognosis and to develop a new predictive model.Results: Real-time q-PCR indicated that serum miR-146 a-5 p, mi R-122-3 p and mi R-328-3 p levels were significantly upregulated in ACLF patients compared to chronic hepatitis B and chronic asymptomatic HBV carriers patients. In addition, multivariate regression analyses indicated that Na+, INR, gastrointestinal bleeding and mi R-122-3 p are all independent factors that are reliable and sensitive to the prognosis of HBV-ACLF. Therefore, we developed a new model for the prediction of HBV-ACLF disease state: Y = 0.402 × Na+-1.72 × INR-4.963 × gastrointestinal bleeding(Yes = 0; No = 1)-0.278 ×(mi R-122-3 p) + 50.449. The predictive accuracy of the model was 95.3% and the area under the receiver operating characteristic curve(AUROC) was 0.847.Conclusions: Expression levels of these mi RNAs(miR-146 a-5 p, mi R-122-3 p and mi R-328-3 p) positively correlate with the severity of liver inflammation in patients with ACLF and may be useful to predict HBV-ACLF severity.

Visual SLAM in dynamic environments based on object detection

A great number of visual simultaneous localization and mapping(VSLAM)systems need to assume static features in the environment.However,moving objects can vastly impair the performance of a VSLAM system which relies on the static-world assumption.To cope with this challenging topic,a real-time and robust VSLAM system based on ORB-SLAM2 for dynamic environments was proposed.To reduce the influence of dynamic content,we incorporate the deep-learning-based object detection method in the visual odometry,then the dynamic object probability model is added to raise the efficiency of object detection deep neural network and enhance the real-time performance of our system.Experiment with both on the TUM and KITTI benchmark dataset,as well as in a real-world environment,the results clarify that our method can significantly reduce the tracking error or drift,enhance the robustness,accuracy and stability of the VSLAM system in dynamic scenes.

Genetic diagnosis strategy of hereditary non-polyposis colorectal cancer

AIM: To study the characteristics of mismatch repair gene mutation of Chinese hereditary non-polyposis colorectal cancer (HNPCC) and hMLH1 gene promoter methylation, and to improve the screening strategy and explore the pertinent test methods. METHODS: A systematic analysis of 30 probands from HNPCC families in the north of China was performed by immunohistochemistry, microsatellite instability (MSI), gene mutation and methylation detection. RESULTS: High frequency microsatellite instability occurred in 25 probands (83.3%) of HNPCC family. Loss of hMLH1 and hMSH2 protein expression accounted for 88% of all microsatellite instability. Pathogenic muta-tion occurred in 14 samples and 3 novel mutational sites were discovered. Deletion of exons 1-6, 1-7 and 8 of hMSH2 was detected in 3 samples and no large fragment deletion was found in hMLH1. Of the 30 probands, hMLH1 gene promoter methylation occurred in 3 probands. The rate of gene micromutation detection combined with large fragment deletion detection was 46.7%-56.7%. The rate of the two methods in combination with methylation detection was 63.3%. CONCLUSION: Scientific and rational detection strategy can improve the detection rate of HNPCC. Based on traditional molecular genetics and combined with epigenetics, multiple detection methods can accurately diagnose HNPCC.

Metabolomic profiling for identification of metabolites and relevant pathways for taurine in hepatic stellate cells

AIM To develop a reliable and simple method to identify important biological metabolites and relevant pathways for taurine in hepatic stellate cells(HSCs), in order to provide more data for taurine therapy.METHODS All the biological samples were analyzed by using highperformance liquid chromatography-time electrospray ionization/quadrupole-time of flight mass spectrometry. Principal component analysis and partial least squares discriminant analysis were used to identify statistically different metabolites for taurine in HSCs, and metabolomic pathway analysis was used to do pathway analysis for taurine in HSCs. The chemical structure of the related metabolites and pathways was identified by comparing the m/z ratio and ion mode with the data obtained from free online databases.RESULTS A total of 32 significant differential endogenous metabolites were identified, which may be related to the mechanism of action of taurine in HSCs. Among the seven relevant pathways identified, sphingolipid metabolism pathway, glutathione metabolism pathway and thiamine metabolism pathway were found to be the most important metabolic pathways for taurine in HSCs.CONCLUSION This study showed that there were distinct changes in biological metabolites of taurine in HSCs and three differential metabolic pathways including sphingolipid pathway, glutathione pathway and thiamine metabolism pathway might be of key importance in mediating the mechanism of action of taurine in HSCs.