AFT Fathom在某大型化工厂循环水系统水力学计算中的应用

应用AFT Fathom软件对某大型化工厂循环水系统管网进行水力学分析计算,得出循环水系统管网的流量、压力分配情况。与传统手算方法相比,该方法能够优化设计,提高设计准确性,减少工程运行成本,对于同类型给水排水系统的设计优化具有指导意义。

Terahertz toroidal dipole metamaterial sensors for detection of aflatoxin B1

Terahertz metamaterial biosensors have attracted significant attention in the biological field due to their advantages of label-free,real-time and in situ detection.In this paper,a highly sensitive metamaterial sensor with semi-ring mirror symmetry based on toroidal dipole resonance is designed for a new metamaterial biosensor.It is shown that a refractive index sensitivity of 337.5 GHz per refractive index unit can be achieved under an analyte of saturated thickness near a 1.33 THz transmission dip.For biosensor samples where aflatoxin B1 is dropped on the metamaterial surface in our experiment,dip amplitudes of transmission varying from 0.1904 to 0.203 and 0.2093 are observed as aflatoxin B1 concentrations are altered from 0 to 0.001μg·ml-1 and to 0.01μg·ml-1,respectively.Furthermore,when aflatoxin B1 concentrations are 0.1μg·ml-1,1μg·ml-1,10μg·ml-1 and 100μg·ml-1,dip amplitudes of 0.2179,0.226,0.2384 and 0.2527 and dip redshifts of 10.1 GHz,20.1 GHz,27.7 GHz and 37.6 GHz are respectively observed.These results illustrate high-sensitivity,label-free detection of aflatoxin B1,enriching the applications of sensors in the terahertz domain.

Molecular mechanisms of aflatoxin neurotoxicity and potential neuroprotective agents

Aflatoxins(AFTs)represent one of the most notorious classes of deadly mycotoxins produced by certain fungi that are found on agricultural crops.Aflatoxins are highly toxic to mammals and are known to cause a series of detrimental effects,including neuro-,hepato-,nephron-,and immuno-toxicity.In this original review we summarize the mechanisms of aflatoxin-induced neurotoxicity and the clinical potential of novel neuroprotective agents.Aflatoxin B1(AFB1)is the most toxic congener among the 21 identified AFTs.Recent studies have shown that food borne exposure to AFB1 and/or its metabolites often leads to fatal neurotoxicity in animals and humans.Animal studies indicated that AFB1 exposure could induce abnormal behavioral changes,including anxiety,lethargy disorders,depression-like behavior,cognitive,learning and memory defects,and decreased feeding behavior.Mechanistically,AFB1 exposure has been associated with lipid peroxidation,ablation of non-enzymatic and enzymatic antioxidant defense systems and decreased neurotransmitter levels.AFB1 exposure has also been shown to induce DNA damage,apoptosis,pyroptosis,and mitochondrial dysfunction in the brain tissue.Several signaling pathways,including gasdermin D,toll like receptor 2(TLR2),TLR4,Akt,NF-κB,ERK/MAPK,protein kinase C(PKC),and mitochondrial apoptotic pathways have been shown to participate in AFB1-induced neuronal or astrocyte cell death.Targeting these pathways by small molecules(e.g.,quercetin,curcumin,and gallic acid,and dimethyl fumarate),Chinese herbal extracts(e.g.,Artichoke leaf extract,Chelidonium majus ethanolic extract,pumpkin extract,and Crocus sativus L.tea),and probiotic supplements could effectively improve AFB1-induced neurobehavioral abnormalities and neurotoxicity.To date,the precise molecular mechanisms of AFB1-induced neurotoxicity and potential neuroprotective agents remain unclear.In the present review,the clinical manifestations,molecular mechanisms,and potential neuroprotective agents of AFB1-induced neurotoxicity are summarized in the broadest overview.It is most hopeful that this broad reaching review provides valuable insights and stimulates broader discussion to develop the effective neuroprotective agents against aflatoxins.

Foodborne toxin Aflatoxin B_(1)induced glomerular podocyte inflammation through proteolysis of RelA,downregulation of miR-9 and CXCR4/TXNIP/NLRP3 pathway

Aflatoxin B_(1)(AFB_(1))is a naturally-occurring mycotoxin and recognized as the most toxic foodborne toxin,particularly causing damages to kidney.Glomerular podocytes are terminally differentiated epithelial cells.AFB_(1)induces podocyte inflammation,proteinuria and renal dysfunction.Studying the mechanism of AFB_(1)-induced podocyte inflammation and murine kidney dysfunction,we detected that AFB_(1)increased ubiquitindependent degradation of the transcription factor RelA through enhanced interaction of RelA with E3 ubiquitin ligase tripartite motif containing 7(TRIM7)in mouse podocyte clone-5(MPC-5)and mouse glomeruli.Reduction of RelA resulted in decreasing microRNA-9(miR-9)and activating the chemokine receptor 4(CXCR4),thioredoxin interacting protein(TXNIP),and NOD-like receptor pyrin domain-containing 3(NLRP3)signaling axis(CXCR4/TXNIP/NLRP3 pathway),leading to podocyte inflammation.We also determined that downregulation of miR-9 led to CXCR4 expression and the downstream TXNIP/NLRP3 pathway activation.Overexpression of miR-9 or deletion of CXCR4 suppressed AFB_(1)-induced CXCR4/TXNIP/NLRP3 pathway,resulting in alleviating podocyte inflammation and kidney dysfunction.Our findings indicated that ubiquitin-dependent proteolysis of RelA,downregulation of miR-9,and activation of CXCR4/TXNIP/NLRP3 pathway played an essential role in AFB_(1)-induced glomerular podocyte inflammation.Our study revealed a novel mechanism,via RelA,for the control of AFB_(1)’s nephrotoxicity,leading to an effective protection of food safety and public health.

Tissue inhibitor of metalloproteinase-3 expression affects clinicopathological features and prognosis of aflatoxin B1-related hepatocellular carcinoma

BACKGROUND The dysregulation of tissue inhibitor of metalloproteinase-3(TIMP3)was positively correlated with the progression of hepatocellular carcinoma(HCC).However,it is not clear whether TIMP3 expression is associated with the clinico-pathological features and prognosis of aflatoxin B1(AFB1)-related HCC(AHCC).A retrospective study,including 182 patients with AHCC,was conducted to explore the link between TIMP3 expression in cancerous tissues and the clinico-pathological characteristics and prognosis of AHCC.TIMP3 expression was detected by immunohistochemistry and its effects on the clinicopathological features and prognosis of AHCC were evaluated by Kaplan-Meier survival analysis and Cox regression survival analysis.Odds ratio,hazard ratio(HR),median overall survival time(MST),median tumor recurrence-free survival time(MRT),and corresponding 95%confidential interval(CI)was calculated to RESULTS Kaplan-Meier survival analysis showed that compared with high TIMP3 expression,low TIMP3 expression in tumor tissues significantly decreased the MST(36.00 mo vs 18.00 mo)and MRT(32.00 mo vs 16 mo)of patients with AHCC.Multivariate Cox regression survival analysis further proved that decreased expression of TIMP3 increased the risk of death(HR=2.85,95%CI:2.04-4.00)and tumor recurrence(HR=2.26,95%CI:1.57-3.26).Furthermore,decreased expression of TIMP3 protein in tissues with AHCC was significantly correlated with tumor clinicopatho-logical features,such as tumor size,tumor grade and stage,tumor microvessel density,and tumor blood invasion.Additionally,TIMP3 protein expression was also negatively associated with amount of AFB1-DNA adducts in tumor tissues.CONCLUSION These findings indicate that the dysregulation of TIMP3 expression is related to AHCC biological behaviors and affects tumor outcome,suggesting that TIMP3 may act as a prognostic biomarker for AHCC.

Contamination of aflatoxins as threat to the safety of herbal Unani drugs: an overview

Unani medicine is an oldest system of traditional medicine,where drugs of animal,mineral and herbal origin are used for centuries to cure diseases.Unani remedies are now available not only in drug stores,but also in food stores and super markets.Therefore the efficacy and safety of these drugs is very crucial.One of the most serious risks associated with these remedies is,consumer assumes that they are natural,so they are safe.But biological contamination(bacterial,fungal and insect)of herbal medicines is a serious concern.The Aspergillus flavus and Aspergillus parasiticus are the fungal species that occur naturally,release aflatoxins and is a threat to the natural drugs.The World Health Organization has recommended determination of aflatoxins in natural drugs(Unani)as one of the parameter of their safety studies as Aflatoxin contamination is concerned significantly with health and economic loss affecting humans,animals,and agriculture.Aflatoxin B1 is categorized as a group 1 carcinogen by The International Agency for Research on Cancer that causes a variety of health issues.Thus keeping in mind the deleterious health effects of aflatoxins,here,in this review we have made an attempt to summarize the aflatoxins with respect to their origin,occurrence,structure and properties to generate the awareness among the people dealing mainly with Unani herbal drugs.Besides these their toxicity and effects on health have also been discussed.The analytical methods for their determination and some measures to prevent their contamination are also suggested to improve the efficacy and safety of Unani herbal drugs.

川东弧形带三维构造扩展的AFT记录

对川东弧形褶皱带北段、中段和南段的三条剖面,进行了7件样品的磷灰石裂变径迹(AFT)测试,结合前人已发表的4件样品,分析模拟了主要背斜的隆升-剥露热历史.结果表明川东弧形带主体构造变形时间为135→65Ma,即早白垩世早期到晚白垩世晚期.进而建立并对比了三条剖面的构造变形时序,揭示出川东弧形带的三维构造扩展历史:(1)平行于构造线走向,表现为从中心向两翼的构造扩展,弧形带中段的构造变形最早,起始时间为早白垩世早期(约135Ma),北段和南段的变形较晚,起始时间为早白垩世晚期(约100 Ma);(2)垂直于构造线走向,在弧形带北段和中段均表现为由东向西的构造扩展,而在弧形带南段,由于受到前缘华蓥山断裂的影响,表现为自西向东的变形时序.川东弧形带的三维构造扩展历史暗示了"弯山构造"的成因模式,以及华蓥山先存断裂对弧形构造的限制作用.

基于AFT-Delaunay的二维解耦并行网格生成算法

面向平面任意几何区域网格生成,提出了一种将波前法AFT(Advancing Front Technique)与Delaunay法相结合的解耦并行网格生成算法。算法主要思想是沿着求解几何区域惯性轴,采用扩展的AFT-Delaunay算法生成高质量三角形网格墙,递归地将几何区域动态划分成多个彼此解耦的子区域;采用OpenMP多线程并行技术,将子区域分配给多个CPU并行生成子区域网格;子区域内部的网格生成复用AFT-Delaunay算法,保证了生成网格的质量、效率和一致性要求。本算法优先生成几何边界与交界面网格,有利于提高有限元计算精度;各个子区域的网格生成彼此完全解耦,因此并行网格生成过程无需通信。该方法克服了并行交界面网格质量恶化难题,且具有良好的并行加速比,能够全自动、高效率地并行生成高质量的三角网格。

面向JAUMIN的并行AFT四面体网格生成

非结构网格应用软件编程框架JAUMIN(J adaptive unstructured mesh applications infrastructure)支撑了多个千万亿次并行应用软件的快速研发,并已成功应用于重大科学装置结构力学分析与优化设计、裂变能源等领域,在这些应用中,网格生成是重要步骤,为了精确刻画物理现象对应的复杂几何区域,需快速生成高质量和高精度网格。提出了一种无缝对接JAUMIN的AFT(advancing front technique)四面体网格生成并行方法,它支撑基于JAUMIN研发的应用软件进行大规模四面体网格生成,其主要特点是:(1)首先生成几何自适应的粗网格,然后基于粗网格进行分区,再通过子区域的AFT方法保证分区交界处网格的一致性;(2)在并行流程中进行表面网格贴体加密,使网格越细化越贴近真实几何形状;(3)并行流程中插入对分区交界处网格的优化步骤,进一步提高网格质量。该方法能针对实际工程应用模型快速生成数亿规模的四面体网格,可扩展性良好。

基于AFT的链路层自动拓扑发现算法

分析了链路层拓扑发现的重要性和现状 ,讨论了基于 Bridge MIB库的 AFT信息拓扑发现技术的理论、模型和原理 ,提出了在交换域内基于 AFT的链路层拓扑发现的一个通用算法 ,给出了算法伪代码及详细描述 。

Gauss整环上的二维AFT算法

利用整环上的Ｍｂｉｕｓ反演公式，给出了Ｇａｕｓｓ整环上的二维Ｆｏｕｒｉｅｒ系数的ＡＦＴ算法，其方法同样适用于小波级数的系数计算。

不同删失比例下AFT模型与Cox模型表现比较的模拟研究

目的评价当生存数据出现不同删失比例的条件下,AFT模型和Cox模型的表现优劣。方法采用自编SAS宏程序模拟不同参数设置、不同比例均匀删失的Weibull分布,分别采用AFT模型和Cox模型对模拟产生的数据进行拟合,并从偏倚、准确性和覆盖程度三个指标对两个模型的表现进行评价。结果在分布参数和自变量效应值固定的情况下,AFT模型在参数估计偏倚和准确性两方面的表现却始终优于Cox模型。删失比例越大,AFT模型的表现相对而言越优异。而在覆盖程度方面,对于相同参数设置及删失比例的模拟数据,两个模型的表现相似。结论 AFT模型的总体表现优于Cox模型,当删失生存数据同时满足两类模型的应用条件时,应该优先选择偏倚更小、准确性更高的AFT模型进行分析。

GSTM1和T1基因多态性与AFT暴露和肝癌危险关系的研究

应用PCR法检测肝癌病例及对照GSTT1和M1空白基因并结合测定其黄曲霉毒素血清白蛋白加合物水平，结果表明：GSTT1和GSTM1空白基因在肝癌病例和对照中分布不均衡，同两种基因均为非空白型者比较，仅GSTT1为空白基因型者患肝癌危险增加2．43倍（OR＝2．34，95％CI1．01～5．46），而两种基因均为空白基因者则患肝癌危险增加了2．43倍（OR＝3．43，95％CI．50～7．91），且血清中AFT－HSA加合物水平明显增高（P＜0．05）；AFT－HSA与肝癌危险度间生物学梯度关系具有统计学显著性意义。提示GSTT1和M1基因与黄曲霉毒素白蛋白加合物可能是筛检肝癌高危个体具有应用价值的一类生物标志物。

AFT流体分析软件在发电厂优化设计中的应用

针对电力设计过程中管道阻力计算采用手工编制的表格,效率低下、准确度低且适应性差的问题,提出了采用AFT流体分析软件,对管道阻力进行计算,可以大大提高阻力计算的效率和准确性,实现发电厂的精细化设计和优化设计。

美国中小学教师工资的当前状况——美国教师联合会(AFT)2007年教师工资调查报告简介

美国教师联合会于2007年3月29日公布了调查报告,内容涉及到2005年的美国教师工资情况。报告分别从教师平均工资、初任教师工资、教师工资购买力、与经济发展和物价上涨的比较等角度,展示了教师工资近几十年来的变化趋势,在指出提高教师工资迫在眉睫的基础上,提出了提高教师工资的具体目标并论证了其可行性。

基于AFT模型的化工装备管理系统预警设计

近年来我国的一些大型石化企业灾难频发,给国家和企业造成了很大的损失。避免灾难性事故发生的最好办法是在大型控制与装备管理系统中设计相应的预警系统。在预警系统中要根据系统相关的很多定性和定量指标对系统目前状况做出科学准确的定量评价。该文提出的预警算法是一种将层次分析法、模糊综合评判和T标准分计算等多种模型有机结合起来,可以对一些由定性和定量预警系统组成的复杂系统进行评价的算法,根据评价结果及时进行预警处理。

基于CMOS图像传感器的AFTB_1大米筛查技术研究

被AFTB1污染的大米具有强烈的致癌作用,会损害人们的身体健康。快速有效地筛查出被AFTB1污染的大米是保证食品安全和身体健康的有效措施,可以促进贸易交流和社会经济的发展。为此,分析了AFTB1的荧光特性,以紫外光LED作为激发光源,采用CMOS图像传感器采集荧光,使用单片机进行数据处理和控制,设计出AFTB1筛查系统。试验结果表明:AFTB1筛查系统具有较高的灵敏度和精度,可以快速有效地筛查出被AFTB1污染的大米。

基于微振动监测的AFT厂房结构-浆液耦合振动特性

AFT氧化风机房是脱硫工艺中的一种钢筋混凝土结构支撑钢罐的复合结构,结构产生的明显振动不利于正常生产运营,因此针对AFT结构进行现场监测和模拟计算.首先对AFT结构进行现场调查,基于一种AFT结构视频监测与局部监测相结合的方法对其进行监测,随后又提出简化搅拌机及氧化风作用的模拟方法,通过数值模拟对AFT结构振动特性进行研究.结果表明:对AFT结构进行视频监测可快速明确结构运动轨迹;局部监测结果表明搅拌机作用是结构振动的主要因素,氧化风的鼓入加剧了结构振动响应,因此造成了结构各柱间填充墙不同程度的损伤;将数值模拟结果与监测结果对比,验证了简化搅拌机及氧化风作用的计算方法,可为分析此类结构振动响应、损伤机制以及加固设计提供参考.

带离散辅助协变量的AFT模型的B-J估计

为处理协变量随机缺失的AFT模型的参数估计问题,首先利用离散辅助协变量对缺失的协变量进行了插补,再结合Buckley-James方法提出了带辅助信息的AFT模型的一种参数估计方法.此方法作为B-J估计在不完全协变量情形下的一个推广,无须指定模型误差项的分布,在应用上有一定的便利性.数据模拟表明:此方法具有较好的估计效果.