Klebsiella pneumoniae infections after liver transplantation:Drug resistance and distribution of pathogens,risk factors,and influence on outcomes

BACKGROUND Liver transplantation(LT)is the only curative treatment for end-stage liver disease.However,LT recipients are susceptible to infection,which is the leading cause of early mortality after LT.Klebsiella pneumoniae infections(KPIs)in the bloodstream are common in LT recipients.We hypothesized that KPIs and carbapenemresistant Klebsiella pneumoniae(CRKP)infections may affect the outcomes of LT recipients.AIM To assess KPI incidence,timing,distribution,drug resistance,and risk factors following LT and its association with outcomes.METHODS This retrospective study included 406 patients undergoing LT at The Third Xiangya Hospital of Central South University,a tertiary hospital,from January 2015 to January 2023.We investigated the risk factors for KPIs and assessed the impact of KPIs and CRKP infections on the prognosis of LT recipients using logistic regression analysis.RESULTS KPI incidence was 7.9%(n=32),with lung/thoracic cavity the most frequent site of infection;the median time from LT to KPI onset was 7.5 d.Of 44 Klebsiella pneumoniae isolates,43(97.7%)and 34(77.3%)were susceptible to polymyxin B or ceftazidime/avibactam and tigecycline,respectively;>70%were resistant to piperacillin/tazobactam,ceftazidime,cefepime,aztreonam,meropenem,and levofloxacin.Female sex[odds ratio(OR)=2.827,95%confidence interval(CI):1.256-6.364;P=0.012],pre-LT diabetes(OR=2.794,95%CI:1.070-7.294;P=0.036),day 1 post-LT alanine aminotransferase(ALT)levels≥1500 U/L(OR=3.645,95%CI:1.671-7.950;P=0.001),and post-LT urethral catheter duration over 4 d(OR=2.266,95%CI:1.016-5.054;P=0.046)were risk factors for KPI.CRKP infections,but not KPIs,were risk factors for 6-month all-cause mortality post-LT.CONCLUSION KPIs occur frequently and rapidly after LT.Risk factors include female sex,pre-LT diabetes,increased post-LT ALT levels,and urethral catheter duration.CRKP infections,and not KPIs,affect mortality.

MLN4924通过抑制类泛素化通路上调人肺腺癌A549细胞中PD-L1的表达

目的:探究MLN4924对肺腺癌A549细胞中程序性死亡-配体1(PD-L1)表达的影响及其可能的内在机制。方法:体外培养A549细胞,按(0、0.25、0.5、0.75、1、5、10μmol/L)MLN4924分组分别处理24、48、72 h后,CCK-8法检测细胞增殖抑制率,作图并计算各组半数抑制浓度(IC_(50)),流式细胞术检测PD-L1的表达,选择最适时间72 h及其IC_(50)用于后续实验。后续实验按(0、0.469μmol/L)MLN4924分组培养72 h,Western blot法检测FBXW2蛋白、肌段同源盒2(MSX2)蛋白、Y-染色体性别决定基因盒2(SOX2)蛋白、PD-L1蛋白表达,qPCR法测定PD-L1 mRNA表达。结果:MLN4924在24、48、72 h的IC_(50)值分别为(1.976、0.647、0.469)μmol/L;与对照组相比,实验组A549细胞PD-L1表达均上调,呈时间-浓度依赖性。与对照组相比,实验组A549细胞FBXW2、SOX2蛋白表达降低,MSX2蛋白、PD-L1 mRNA及蛋白表达均增加。结论:MLN4924通过抑制类泛素化通路上调人肺腺癌A549细胞中PD-L1表达。

Lacustrine sedimentary responses to earthquakes—soft-sediment deformation structures since late Pleistocene:A review of current understanding

The traces left by earthquakes in lacustrine sediments are studied to determine the occurrence of ancient earthquakes by identifying seismically induced soft-sediment deformation structures(SSDS).Dating can help reconstruct the relative frequency of earthquakes.Identifying seismically induced seismites,which carry abundant seismic information from numerous SSDS,is both critical and challenging.Studying the deformation mechanism of SSDS and learning about the common criteria of seismically induced SSDS improve the identification of earthquake triggers.With better research into SSDS,seismic events can be effectively captured,and temporal constraints can be carried out by 14C dating and optically stimulated luminescence(OSL)dating to identify and date the occurrence of ancient earthquakes.The present contribution primarily addresses the meaning and mechanism of SSDS and their relationship with earthquake magnitude as well as the common criteria of the SSDS induced by earthquakes.

血清miRNA-21-5p、miRNA-122-5p表达水平对绝经后骨质疏松性髋部骨折的诊断价值评价

目的分析miRNA-21-5p、miRNA-122-5p表达水平对绝经后骨质疏松性髋部骨折的诊断价值。方法选取本院于2020年1~12月收治的60例患者分为四组进行研究。分析miRNA-21-5p、miRNA-122-5p水平变化并分析其对疾病的反映情况。结果四组的miRNA-21-5p、miRNA-122-5p并无明显差异(P>0.05);骨质疏松性髋部骨折组水平明显高于正常组;且其对疾病的诊断准确率明显更高。结论miRNA-21-5p、miRNA-122-5p能够对骨质疏松等疾病进行预测及诊断,可作为骨质疏松性髋骨骨折的诊断指标。

糖尿病视网膜病变患者PRP术后预后的相关影响因素

目的:探讨糖尿病视网膜病变(DR)患者全视网膜激光光凝术(PRP)术后预后相关影响因素。方法:收集2015-09/2017-09来我院就诊的DR患者182例301眼,根据病变分期给予患者不同的治疗方式,增殖前期患者进行次全视网膜光凝治疗,DR增殖早期患者进行标准全视网膜光凝治疗,高危患者进行超全视网膜光凝治疗。对患者随访6mo,记录患者的预后情况,筛选对视力变化有影响的相关因素。结果:对单因素有意义的因素进行多因素Logistic回归分析可以得出,年龄、初诊视力、低密度脂蛋白胆固醇、总胆固醇、甘油三酯、高密度脂蛋白胆固醇、糖化血红蛋白、黄斑水肿严重程度、血压与预后具有相关性( P <0.05)。结论:高血压、年龄大、高血脂、初诊视力差、糖化血红蛋白水平高、黄斑水肿严重对DR患者激光光凝术后的预后造成一定影响。

Healing of Stoma After Magnetic Biliary-Enteric Anastomosis in Canine Peritonitis Models

Objective To assese the healing of stoma after magnetic anastomosis for the reconstruction of biliary-enteric continuity under severe inflammation. Methods Acute bile duct injury was constructed as a bile peritonitis model in mongrel dogs(n=32). Magnetic anastomosis(group A, n=16) and traditional suture anastomosis(group B, n=16) were performed to reconstruct the biliary-enteric continuity in one stage. Half of the dogs in each group were euthanized on the 30 th postoperative day, and the other half on the 90 th postoperative day to harvest the stoma region. The healing conditions of the stoma after the 2 anastomotic approaches were observed with naked eyes, under light microscope and scanning electron microscope. Results The stoma leakage rate(50% versus 0% on the 30 th postoperative day, 37.5% versus 12.5% on the 90 th postoperative day, both P<0.05) and stenosis degree(13.9%±0.3% versus 7.1%±0.3% on the 30 th postoperative day, 17.2%±0.4% versus 9.4%±0.4% on the 90 th postoperative day, both P<0.01) were significantly higher in group B than in group A. Compared with traditional manual anastomoses, the histological analysis under light and electron microscope showed a more continuous stoma with more regular epithelium proliferation and collagen arrangement, less inflammation in group A. Conclusions Magnetic anastomosis stent ensures better healing of the stoma even under the circumstance of severe inflammation.

Investigation of shale gas microflow with the Lattice Boltzmann method

In contrast to conventional gas-bearing rocks, gas shale has extremely low permeability due to its nano- scale pore networks. Organic matter which is dispersed in the shale matrix makes gas flow characteristics more complex. The traditional Darcy＇s law is unable to estimate matrix permeability due to the particular flow mechanisms of shale gas. Transport mechanisms and influence factors are studied to describe gas transport in extremely tight shale. Then Lattice Boltzmann simulation is used to establish a way to estimate the matrix permeability numerically. The results show that net desorption, diffu- sion, and slip flow are very sensitive to the pore scale. Pore pressure also plays an important role in mass fluxes of gas. Temperature variations only cause small changes in mass fluxes. The Lattice Boltzmann method can be used to study the flow field in the micropore spaces and then provides numerical solutions even in complex pore structure models. Understanding the transport characteristics and establishing a way to estimate potential gas flow is very important to guide shale gas t＇eserve estimation and recovery schemes.

Investigation of Heterogeneous Ice Nucleation on the Micro-Cubic Structure Superhydrophobic Surface for Enhancing Icing-Delay Performance

The aim of this study is to explore the heterogeneous ice nucleation behavior based on controllable micro-cubic array structure surfaces from the statistic perspective.To this end,we firstly constructed a group of micro-cubic array structures on silicon substrates by a selective plasma etching technique.After grafting low-free-energy substance,the as-constructed micro-cubic array structure surfaces exhibited higher non-wettability with the water contact angle being up to 150°.On this basis,500 cycles of freezing and melting processes were accurately recorded to analyze the instantaneous ice nucleation behavior according to the statistical results of freezing temperature.As a consequence,the statistical freezing temperature of the sample with micro-spacing distance of 40μm is as low as−17.13°C.This microstructure configuration(conforming to Cassie-Baxter wetting regime)not only could entrap more air pockets,but also achieved lower solid-liquid contact area,resulting in lower ice nucleation rate(~2–3 orders of magnitude less than that on the flat substrate).Furthermore,the gradually increasing micro-spacing distance to 60μm would induce the transition from CassieBaxter to Wenzel wetting state,leading to higher freezing probability and ice nucleation rate.The complete understanding on microstructure configuration improving the ice nucleation will lay the foundation stone for the microstructure design of ice-repellent materials.

洪湖地区莲藕产业发展现状、存在问题及对策建议

导读:莲藕产业在洪湖地区农业增效、农民增收中发挥着重要作用,当地以地理资源为优势,以“洪湖莲藕”区域公用品牌为载体,以安全品质为核心,以消费者需求为导向,形成了洪湖有特色、有规模、有品牌、有品位、有文化、有竞争力的特色产业。本文分析了洪湖地区莲藕产业具备的优势条件、做法成效、存在问题及相应对策。

Pasteurella multocida capsular:lipopolysaccharide types D:L6 and A:L3 remain to be the main epidemic genotypes of pigs in China

Pasteurella multocida is a leading cause of respiratory disorders in pigs.This study was designed to understand the genotypical and antimicrobial resistant characteristics of P.multocida from pigs in China.To achieve this,we briefly investigated 158 P.multocida isolates from pigs with respiratory disorders in China between 2019 and 2020.Genotyping through multiplex PCR assays assigned these 158 isolates into capsular genotypes A(60.13%,95/158),D(35.44%,56/158),F(4.43%,7/158),and/or lipopolysaccharide(LPS)genotypes L3(28.48%,45/158)and L6(66.46%,105/158).In addition,eight isolates(5.06%,8/158)were found to be nontypable using the LPS genotyping method.When combining the capsular genotypes and the LPS genotypes,D:L6(34.81%,55/158)and A:L6(31.65%,50/158)were the predominant genotypes,followed by A:L3(24.05%,38/158).PCR detection of virulence factor-encoding genes showed that over 80%of the isolates were positive for exbB,tonB,exbD,ompH,ptfA,fimA,sodA,sodC,fur,ompA,oma87,plpB,hsf-2,nanH and hgbB,suggesting the presence of these genes were broad characteristics of P.multocida.We also found approximately 63.92%(101/158),51.27%(81/158),8.86%(14/158),7.59%(12/158),3.16%(5/158),0.63%(1/158),and 0.63%(1/158)of the isolates grew well in media with the presence of colistin(4μg/mL),tetracycline(16μg/mL),tigecycline(1μg/mL),ampicillin(32μg/mL),chloramphenicol(32μg/mL),cefepime(16μg/mL),and ciprofloxacin(1μg/mL),respectively.This study contributes to the understanding of genotypes and antimicrobial resistance profile of P.multocida currently circulation in pigs of China.

Parameter identification and state-of-charge estimation approach for enhanced lithium–ion battery equivalent circuit model considering influence of ambient temperatures

It is widely accepted that the variation of ambient temperature has great influence on the battery model parameters and state-of-charge(SOC) estimation, and the accurate SOC estimation is a significant issue for developing the battery management system in electric vehicles. To address this problem, in this paper we propose an enhanced equivalent circuit model(ECM) considering the influence of different ambient temperatures on the open-circuit voltage for a lithium-ion battery. Based on this model, the exponential-function fitting method is adopted to identify the battery parameters according to the test data collected from the experimental platform. And then, the extended Kalman filter(EKF) algorithm is employed to estimate the battery SOC of this battery ECM. The performance of the proposed ECM is verified by using the test profiles of hybrid pulse power characterization(HPPC) and the standard US06 driving cycles(US06) at various ambient temperatures, and by comparing with the common ECM with a second-order resistance capacitor. The simulation and experimental results show that the enhanced battery ECM can improve the battery SOC estimation accuracy under different operating conditions.

Game Theory Based Decision Coordination Strategy of Agricultural Logistics Service Information System

Under the background of“Internet plus”rapid development,the agricultural logistics industry should apply information technology to every link of the agricultural product logistics industry chain.By making full use of the decision making module of the agricultural logistics information system,we can realize the full sharing of information and data resources,which makes the decision-making scheme of the agricultural logistics information system more optimized.In real economic society,the uncertainty and mismatch between the customer’s logistics service demand and the logistics service capability that the logistics service function provider can provide,that is,when the two information are asymmetric,how to use the third-party contract to coordinate the income and profit distribution of the two,to make the information system decision making more reasonable?This paper mainly studies the coordination scheme of agricultural logistics information system decision making under uncertain output and demand information by introducing the spot market.A joint coordination strategy based on revenue sharing and penalty feedback contracts proposes decentralized decision making based on game theory.Experiments show that the flexible ordering strategy proposed in this paper can reduce the logistics service supply chain’s uncertainty and significantly improve the logistics service supply chain’s overall income level through coordination contracts.

Calculation of the Water Distribution Networks Based on the Theory of Slow Transient Flow

Urban water supply network is a modern urban survival and development of the infrastructure of a city,and its normal running conditions have important significance. The actual hydraulic process in the variableload water distribution networks can be treated as the slow transient flow which belongs to the unsteady flow. This paper analyzes the multi-loops network slow transient model based on graph theory,and the link flow matrix is treated as the variables of the discrete solution model to simulate the process of the slow transient flow in the network. With the simulation of hydraulic regime in an actual pipe network,the changing laws of the flow in the pipes,nodal hydraulic heads and other hydraulic factors with the passage of time are obtained. Since the transient processes offer much more information than a steady process,the slow transient theory is not only practical on analyzing the hydraulic condition of the network,but also on identifying hydraulic resistance coefficients of pipes and detecting the leakage in networks.

胫骨前内侧撞击骨折在膝关节后外复合体损伤中的发生率及其临床特点

目的胫骨前内侧撞击骨折在膝关节后外复合体损伤中的发生率并分析其临床特点。方法收集2018年1月至2021年1月在喀什地区第一人民医院运动医学科收治的153例膝关节后外复合体损伤患者。根据影像学资料统计胫骨平台前内侧撞击骨折的发生率。根据有无胫骨前内侧撞击骨折将患者分为两组,胫骨前内侧撞击骨折患者作为观察组,非胫骨前内侧撞击骨折患者作为对照组,比较两组患者不稳定性程度。再根据骨折块大小将胫骨前内侧撞击骨折组分为边缘型骨折组(骨折块横径<5 mm)和压缩型骨折组(骨折块横径≥5 mm),比较两组患者的不稳定性程度及合并损伤情况。结果153例膝关节后外复合体损伤患者中观察组10例(6.54%),对照组143例(93.46%)。相比对照组,观察组患者后向不稳定性更严重(P=0.016)。与边缘型骨折组相比,压缩型骨折组患者后向不稳定更为严重(P=0.018)。压缩型骨折组合并腓总神经损伤的发生率高于边缘型骨折组(P=0.035)。结论虽膝关节后外复合体损伤中胫骨前内侧撞击骨折患者的发生率低,但其后向不稳定性更严重,其中压缩型骨折患者的后向不稳定型及血管神经损伤更为严重。临床上应重视对膝关节后外复合体损伤合并胫骨平台前内侧撞击骨折患者的后向稳定性检查及血管神经情况检查。

肝脏血管周上皮样细胞瘤38例临床诊治分析

背景与目的:肝脏血管周上皮样细胞瘤(PEComa)是一种少见的肝脏原发性肿瘤,由于缺乏特异性的症状及影像特征,容易误诊为肝细胞癌、肝血管瘤,影响临床治疗。为探索肝脏PEComa的疾病特点及诊治方法,本研究通过总结我院既往收治的肝脏PEComa患者临床病理资料,对其临床诊疗和预后进行分析,旨在提高对该疾病的诊疗水平。方法:回顾2010年7月—2021年6月期间中南大学湘雅医院普通外科收治的38例肝脏PEComa患者的临床病理资料,对患者的临床特点、影像学表现、病理特点、治疗及预后并进行分析。结果:38例患者中,女性28例(73.7%),男性10例(26.3%),中位年龄46 (21~66)岁。38例患者共发现40个肝脏结节,结节的大小1.0~20.0 cm,平均(6.02±4.84) cm,其中位于右肝21个(52.5%),位于左肝17个(42.5%),位于尾状叶2个(5%)。10例患者有临床症状,表现为腹胀和腹痛或寒战和发热。35例患者行术前肝脏彩超检查,病灶表现为高回声(18例)、混合回声(12例)或低回声(5例)肿块。23例患者术前行增强CT检查,增强后动脉期均出现明显增强,19例在门脉期和延迟期表现为低密度,4例在门脉期和延迟期仍有强化。10例行磁共振检查,其中6例病灶T1加权图像呈低信号,T2加权图像为高信号,3例病灶T1为高信号,T2低信号,1例病灶T1和T2均为等信号;所有病例病灶在弥散加权图像中均表现为高信号。1例行18F-FDG PET/CT检查,肿瘤葡萄糖代谢低,胆碱成像显示病变摄取量异常增高,并在术前误诊为肝细胞癌。所有患者都接受了肝切除手术治疗,包括2例被诊断为肝血管瘤并在外院接受肝动脉栓塞术治疗后发生破裂出血患者。术后病理诊断均为肝脏PEComa,各标志物免疫组化染色阳性率分别为:HMB-45为100%(38/38),CD34为47.4%(18/38),melan-A为44.7%(17/38),SMA为21.1%(8/38)。38例中有34例获得完整随访资料,随访时间3~133个月,中位随访时间为60.5个月,随访期间仅1例于术后3年死亡,余患者均未发现肿瘤复发或转移。结论:肝脏PEComa缺乏特异性的临床表现和影像学特征,术后组织病理学检查是诊断的金标准,当出现症状、良恶性难以鉴别时应尽早手术切除。

《仙后》中的历史书写与英格兰民族身份建构

埃德蒙·斯宾塞在其史诗《仙后》中采用编年史、地方志和史诗预言三种历史书写形式建构了英格兰民族的历史、地理和宗教身份,由此确立了该诗“英格兰民族史诗”的地位。《仙后》中的历史书写不仅彰显了史诗中史与诗的互动,构成史诗中英格兰民族身份建构的重要途径,而且确证了历史文化记忆对强化英格兰民族认同、彰显英格兰民族身份中独特的英格兰性的关键作用。

Fertilization practices affect biological nitrogen fixation by modulating diazotrophic communities in an acidic soil in southern China

Biological nitrogen(N)fixation(BNF)driven by diazotrophs is an important pathway for N input in agricultural ecosystems.However,free-living BNF and its associated diazotrophic communities under different fertilization practices in acidic soils are poorly studied.Here,we conducted a long-term(29 years)fertilization experiment to explore how fertilization affected free-living BNF via changing biotic and abiotic variables.The fertilization treatments included an unfertilized control(CK),chemical N,phosphorus(P),and potassium(K)fertilizers(NPK),NPK plus lime(NPKL),NPK plus straw(NPKS),NPK plus straw and lime(NPKSL),and NPK plus manure(NPKM).Compared with CK(1.51 nmol C_(2)H_(2)g^(-1)d^(-1)),BNF rate was significantly(P<0.05)higher in NPKM(1.99 nmol C_(2)H_(2)g^(-1)d^(-1))but lower in NPK(0.55 nmol C_(2)H_(2)g^(-1)d^(-1)),NPKL(0.61 nmol C_(2)H_(2)g^(-1)d^(-1)),and NPKS(0.69nmol C_(2)H_(2)g^(-1)d^(-1)).Similarly,chemical fertilization treatments without manure reduced the gene abundance(0.71×10^(8)-1.18×10^(8)copies g^(-1))andα-diversity(Shannon index,1.11-2.43)of diazotrophic communities,whereas the treatment with manure had a positive effect on diazotrophic abundance(3.23×10^(8)copies g^(-1))and Shannon index(3.36).Non-parametric multivariate analysis of variance(PERMANOVA)suggested that manure application(R^(2)=0.212,P=0.001)had a stronger influence on diazotrophic community composition than the addition of lime(R^(2)=0.115,P=0.019)or straw(R^(2)=0.064,P=0.161).Random forest modeling revealed that BNF rates can be significantly(P<0.05)explained by soil pH(9.9%),diazotrophic community attributes(composition,8.5%;Chao 1 index,8.1%;abundance,6.0%;Shannon index,5.7%),and soil total carbon(5.1%).Partial least squares path modeling(PLS-PM)suggested that the diazotrophic community attributes and soil properties mainly provided direct and indirect contributions to the variations in BNF rates,respectively.The dominant genera,Pelomonas,Azospirillum,and Dechloromonas,were positively associated with BNF rates,with their members being observed as keystone species in the community network.Application of chemical fertilizers combined with manure is an effective practice for improving BNF in acidic soils by affecting soil diazotrophic communities.

优先解剖肝实质法在腹腔镜下鞘外肝蒂血流阻断中的应用:附解剖性肝中叶切除1例

背景与目的:术中出血是腹腔镜下解剖性肝叶切除术(ALH)中转开腹的主要原因,入肝血流的有效控制是ALH成功实施的关键。传统的ALH肝蒂血流阻断遵循"肝蒂优先"的思路,即先游离并离断肝蒂(具体可分为"鞘内解剖法"和"鞘外解剖法"),再行肝实质离断,但它耗时费力。笔者在长期的临床工作中摸索出了优先解剖肝实质再离断肝蒂的入肝血流阻断技术,将其命名为"肝实质解剖优先"(LPDF)法。这一方法未扩大手术范围,仅调整了手术操作顺序,可简化入肝血流的阻断,有利于ALH的推广应用。本文介绍1例应用LPDF行腹腔镜下解剖性肝中叶切除的病例,初步总结LPDF的技术特点。方法:回顾性分析2019年10月1例应用LPDF行腹腔镜下解剖性肝中叶切除术肝癌患者的临床资料。患者肝癌病灶累及8、5段和4b段。术中游离肝周韧带,阻断第一肝门,超声刀沿镰状韧带右侧(左侧切除线)向第一及第二肝门方向充分解剖肝实质,显露适当长度的右前叶肝蒂后予结扎并离断,从而显示出右肝前叶缺血线(右侧切除线),再行右侧肝实质解剖。直至两侧切面汇合,将肝中叶及肿块整块切除。结果:手术时间为260min,术中出血量为300m L,未输血;术后第3天肠道功能恢复,术后第6天出院,未发生腹腔内大出血或胆汁漏等并发症。术后1个月门诊复查彩超发现117mm×87mm术区积液,但患者无发热、腹痛症状,白细胞数目及总胆红素正常,未予处理,术区积液逐渐吸收。结论:LPDF安全可行,它简化了腹腔镜肝中叶切除鞘外肝蒂血流阻断,值得进一步研究其在ALH中的应用价值。

Regulation of pancreatic exocrine in ruminants and the related mechanism: The signal transduction and more

The unique structure of the stomach,including the rumen,reticulum,omasum,and abomasum,indicates the differences between the ruminant and monogastric animals in the digestion of nutrients.This difference is reflected in the majority of dietary nutrients that may be fermented in the rumen.Significant proteins and a certain amount of starch can flow to the small intestine apart from rumen.The initial phase of small intestinal digestion requires pancreatic digestive enzymes.In theory,the enzymatic digestion and utilization efficiency of starch in the small intestine are considerably higher than that in the rumen,but the starch digestibility in the small intestine is quite low in ruminants.Therefore,improving the digestion of nutrients,especially starch in the small intestine is more urgent for high-yield ruminants.Although the pancreas plays a central role in nutrient digestion,the progress of research investigating pancreatic exocrine regulation in the ruminant is slow due to some factors,such as the complex structure of the pancreas,the selection of experimental model and duration,and internal(hormones or ages) and external(diet) influences.The present review is based on the research findings of pancreatic exocrine regulation of dairy animals and expounded from the physiological structure of the ruminant pancreas,the factors affecting the digestion and exocrine processing of carbohydrates,and the regulatory mechanism governing this process.The review aims to better understand the characteristics of enzymatic digestion,thereby advancing pancreatic exocrine research and improving the digestion and utilization of nutrients in ruminants.Additionally,this review provides the theoretical basis for improving nutrient utilization efficiency,reducing wastage of feed resources,and promoting the efficient development of the dairy industry.

Multiple-quantum-well-induced unipolar carrier transport multiplication in AlGaN solar-blind ultraviolet photodiode

AlGaN solar-blind ultraviolet(SBUV)detectors have potential application in fire monitoring,corona discharge monitoring,or biological imaging.With the promotion of application requirements,there is an urgent demand for developing a high-performance vertical detector that can work at low bias or even zero bias.In this work,we have introduced a photoconductive gain mechanism into a vertical AlGaN SBUV detector and successfully realized it in a p-i-n photodiode via inserting a multiple-quantum-well(MQW)into the depletion region.The MQW plays the role of trapping holes and increasing carrier lifetime due to its strong hole confinement effect and quantum confinement Stark effect.Hence,the electrons can go through the detector multiple times,inducing unipolar carrier transport multiplication.Experimentally,an AlGaN SBUV detector with a zero-bias peak responsivity of about 0.425 A/W at 233 nm is achieved,corresponding to an external quantum efficiency of 226%,indicating the existence of internal current gain.When compared with the device without MQW structure,the gain is estimated to be about 103 in magnitude.The investigation provides an alternative and effective approach to obtain high current gain in vertical AlGaN SBUV detectors at zero bias.