基于W2ID准则的RichModel隐写检测特征选取方法

数字隐写是信息安全领域一个重要分支,其通过将秘密信息嵌入到数字图像、声音、视频等文件中并通过公开信道(如:Email邮箱、微博推文和即时通信等)进行传递,从而实现信息的隐蔽通信.图像自适应隐写是近年来数字隐写技术的研究热点,而Rich Model特征是检测图像自适应隐写的一大类主流高维特征,这类高维特征在实现对图像自适应隐写较高检测正确率的同时,带来了高额的计算开销和和存储开销,并使得隐写检测中的分类器训练变得极为困难.为此,本文提出了一种基于加权类间距离和类内距离差异准则(W2ID准则)的图像Rich Model隐写检测特征选取方法(记为W2ID-α方法).首先,在对Fisher-based方法这一隐写检测特征经典选取方法进行原理分析的基础上,指出该方法可能存在误删有用特征分量、保留冗余和冲突特征分量的不足;然后,通过将"类内距离差异"原则引入到隐写检测特征分量的可分性度量,提出了基于类间距离和类内距离差异的特征可分性度量准则(简记为2ID准则),给出了类内距离差异的一个相关性质;同时,为了合理体现"类间距离"的重要性,本文提出了基于频数统计加权法的权重分配算法,为该准则分配合理权重,使得对特征分量可分性的度量结果相比传统的Fisher准则更为准确;最后,依据W2ID准则的度量结果,基于决策粗糙集α-正域约简方法约简隐写检测特征分量,并在约简特征分量过程中,将每次处理一个特征分量改进为每次处理一组特征分量,以提升决策粗糙集α-正域约简的效率.提出的W2ID-α方法因无需设置可分性下限,避免了阈值设置不准确可能造成去除有用特征分量的问题,从而消除了现有Steganalysis-α隐写检测特征选取方法依赖经验参数的问题.基于数字隐写领域通用的BOSSbase-1.01图像库10 000幅原始图像和基于经典SI-UNIWARD隐写方法生成的多组隐写图像,针对从这些图像组每幅图像中提取的35263维J+SRM特征和17000维GFR特征(两类典型的图像Rich Model隐写检测特征),进行了一系列特征选取实验,结果表明:本文提出的W2ID-α方法能够在大幅降低Rich Model隐写检测特征维数的同时,基于选取后特征的隐写检测提高了对隐写图像的检测正确率,与Fisher-based、Steganalysis-α和PCA-based等现有典型特征选取方法相比具有显著优势,如对嵌入率=0.1的SI-UNIWARD隐写图像,基于提出的W2ID-α方法将J+SRM特征从35 263维降到2723维的同时,还提高了 3.63%的检测正确率.

Precise prediction model and simplified scoring system for sustained combined response to interferon-α

AIM:To establish a predictive algorithm which may serve for selecting optimal candidates for interferon-α(IFN-α) treatment.METHODS:A total of 474 IFN-α treated hepatitis B virus e antigen(HBeAg)-positive patients were enrolled in the present study.The patients' baseline characteristics,such as age,gender,blood tests,activity grading(G) of intrahepatic inflammation,score(S) of liver fibrosis,hepatitis B virus(HBV) DNA and genotype were evaluated;therapy duration and response of each patient at the 24th wk after cessation of IFN-α treatment were also recorded.A predictive algorithm and scoring system for a sustained combined response(CR) to IFN-α therapy were established.About 10% of the patients were randomly drawn as the test set.Responses to IFN-α therapy were divided into CR,partial response(PR) and non-response(NR).The mixed set of PR and NR was recorded as PR+NR.RESULTS:Stratified by therapy duration,the most significant baseline predictive factors were alanine aminotransferase(ALT),HBV DNA level,aspartate aminotransferase(AST),HBV genotype,S,G,age and gender.According to the established model,the accuracies for sustained CR and PR+NR,respectively,were 86.4% and 93.0% for the training set,81.5% and 91.0% for the test set.For the scoring system,the sensitivity and specificity were 78.8% and 80.6%,respectively.There were positive correlations between ALT and AST,and G and S,respectively.CONCLUSION:With these models,practitioners may be able to propose individualized decisions that have an integrated foundation on both evidence-based medicine and personal characteristics.

Early detection of hepatocellular carcinoma co-occurring with hepatitis C virus infection: A mathematical model

AIM: To develop a mathematical model for the early detection of hepatocellular carcinoma (HCC) with a panel of serum proteins in combination with α-fetoprotein (AFP).METHODS: Serum levels of interleukin (IL)-8, soluble intercellular adhesion molecule-1 (sICAM-1), soluble tumor necrosis factor receptor II (sTNF-RII), proteasome, and β-catenin were measured in 479 subjects categorized into four groups: (1) HCC concurrent with hepatitis C virus (HCV) infection (n = 192); (2) HCV related liver cirrhosis (LC) (n = 96); (3) Chronic hepatitis C (CHC) (n = 96); and (4) Healthy controls (n = 95). The R package and different modules for binary and multi-class classifiers based on generalized linear models were used to model the data. Predictive power was used to evaluate the performance of the model. Receiver operating characteristic curve analysis over pairs of groups was used to identify the best cutoffs differentiating the different groups.RESULTS: We revealed mathematical models, based on a binary classifier, made up of a unique panel of serum proteins that improved the individual performance of AFP in discriminating HCC patients from patients with chronic liver disease either with or without cirrhosis. We discriminated the HCC group from the cirrhotic liver group using a mathematical model (-11.3 + 7.38 × Prot + 0.00108 × sICAM + 0.2574 × β-catenin + 0.01597 × AFP) with a cutoff of 0.6552, which achieved 98.8% specificity and 89.1% sensitivity. For the discrimination of the HCC group from the CHC group, we used a mathematical model [-10.40 + 1.416 × proteasome + 0.002024 × IL + 0.004096 × sICAM-1 + (4.251 × 10-4) × sTNF + 0.02567 × β-catenin + 0.02442 × AFP] with a cutoff 0.744 and achieved 96.8% specificity and 89.7% sensitivity. Additionally, we derived an algorithm, based on a binary classifier, for resolving the multi-class classification problem by using three successive mathematical model predictions of liver disease status.CONCLUSION: Our proposed mathematical model may be a useful method for the early detection of different statuses of liver disease co-occurring with HCV infection.

Numerical Modeling of Growth Kinetics of Pro-eutectoid Ferrite Transformed from Austenite in Fe-C-∑X Alloys

In the present paper, a numerical modeling was developed to simulate the growth kinetics of ferrite transformed from austenite in Fe-C-∑X （X denotes substitution elements, such as Mn, Ni, Cr etc.） steels by solving the diffusion equation using finite difference method （FDM）. Coupled with the kinetic modeling, thermodynamic calculations were carried out to determine the γ/α phase equilibrium conditions using a para-equilibrium （PE） model. The dissipation of free energy for γ→α phase transformation due to the so-called solute drag effect （SDE） was taken into account in the thermodynamic modeling. With this modeling, simulations on the growth kinetics of ferrite in the steels containing austenite-stabilizing and ferrite-stabilizing elements （such as Ni, Mn and Si, Cr, respectively） were performed, which indicates that it deviates from the parabolic growth rate law after the initial stage of transformation. The results were compared with the experimental values given by Bradley and Aaronson, showing that this model has a reasonably good accuracy to predict the growth kinetics of ferrite.

Reassessment subacute MPTP-treated mice model of Parkinson disease

OBJECTIVE(1) To estimate the value of the subacute MPTP mouse model in aspects of behavioral performance,biochemical changes and pathological abnormalities.(2) To find effective positive drugs.METHODS Male C57 BL/6 mice were injected with MPTP(30 mg·kg^(-1)·d^(-1),ip) for 5 consecutive days.Three days before MPTP injection,the mice were orally administered selegiline(3 mg·kg^(-1)·d^(-1)),pramipexole(3 mg·kg^(-1)·d^(-1)),or medopar(100 mg·kg^(-1)·d^(-1)) for 18 d.Behavioral performance was assessed in the open field test,pole test and rotarod test.Neurotransmitters in the striatum were detected using HPLC.Protein levels were measured by Western blot.Pathological characteristics were examined by immunohistochemistry.Ultrastructure changes were observed by electron microscopy.RESULTS The subacute MPTP treatment did not induce evident motor defects despite severe injuries in the dopaminergic system.Additionally,MPTP significantly increased the α-synuclein levels and the number of astrocytes in the striatum,and destroyed the blood-brain barrier(BBB) in the substantianigra pars compacta.Both selegiline and pramipexole were able to protect the mice against MPTP injuries.CONCLUSION The subacute MPTP mouse model does not show visible motor defects;it is not enough to evaluate the validity of a candidate just based on behavioral examination,much attention should also be paid to the alterations in neurotransmitters,astrocytes,α-synuclein and the BBB.In addition,selegiline or pramipexole is a better choice than medopar as an effective positive control for the subacute MPTP model.

Unusual W-shaped Galvanic Cell Model of ISCC of α-brass in Neutral Mattsson's Solution

Intergranular stress corrosion cracking (ISCC) of α-brass in neutral Mattsson's solution was found to be controlled by an unusual 'W'-shaped galvanic cell whose cathode is the grain boundary oxide film (G.B.0. film) and surface film and the anode is fresh metal at the cracked tip on both sides of the G.B.0. film. Redox reactions involved in the cell have been proposed here. According to this mdel, initidtion of ISCC is caused by the rupturing of surface film along grain boundaries, thus forming a galvanic cell. Propagation of ISCC resulted from alternate advances of G.B.0. film and dissolution on both sides of G.B.0. film caused by the effect of electrochemical reaction. This work developed an effective approach to investigate the embrittlement process at the tip of the crack, by increasing the length of the embrittlement region through constant strain test and distinguishing the morphology and the nature of the corrosion products by optical microscopy and scanning electron microscopy (SEH).

通货膨胀下的α-鲁棒最优投资策略研究

该文主要研究通货膨胀下具有模型不确定性的最优投资问题.假定金融市场上存在无风险资产、风险资产以及用于对冲通胀风险的通货膨胀指数债券可投资,其中风险资产价格服从CEV模型,而后利用价格指数水平折现各类资产价格呈现其真实价格,运用α-maxmin均值方差效用函数建立投资模型,并通过求解HJB方程获得均衡投资策略与值函数的显式解.最后结合数值仿真分析了参数变动下的最优投资策略变化趋势.

骨骼肌钝挫伤大鼠模型的构建与评价

目的:建立可靠、稳定、符合临床实际的大鼠骨骼肌钝挫伤模型。方法:通过170g重物,70cm高度,用底部直径0.5cm弹簧缓冲聚合式打击部,以引导下落的撞击方法,连打5次,建立大鼠腓肠肌钝挫伤模型。分别于造模后0h、12h、24h、3d、7d、14d,采用Cat Walk分析系统评估大鼠步态改变;HE染色观察大鼠局部组织病理学改变,透射电子显微镜观察局部组织超微结构的改变。酶联免疫吸附试验(enzyme linked immunosorbent assay,ELISA)检测局部组织肿瘤坏死因子(tumor necrosis factor-α,TNF-α)含量变化。结果:(1)Cat Walk步态参数:与空白组相比,模型组的平均速度与最大速度变化率均明显下降,差异具有显著性意义(P<0.001);与健康侧肢体组相比:受伤侧肢体组肢体的最大接触面积、足印面积和站立相持续时间均明显减少,差异具有显著性意义(P<0.05)。(2)HE染色:观察到3d后大量炎症细胞浸润,肌纤维大量溶解坏死,14d尽管瘢痕组织仍然存在,但HE染色上的组织修复与空白组几乎没有区别。(3)超微结构:打击后0h部分肌浆网出现空泡现象,3d肌纤维和部分肌浆网溶解,炎症反应加重,到14d基本恢复正常。(4)TNF-α表达水平:0h开始至12h这段时间内,TNF-α含量即开始逐渐升高达到高峰,并在损伤后12—72h一直保持较高水平,与空白组相比差异具有显著性意义(P<0.05),到14d基本恢复正常水平。结论:以锤重170g、70cm高度、底部带弹簧缓冲装置的直径0.5cm圆钝型打击头,连打5次,可对大鼠骨骼肌造成中度损伤,其自然恢复时间至少14d,适用于大鼠骨骼肌钝挫伤模型的建立,可为今后大鼠骨骼肌钝挫伤模型提供参考依据。

脱硫石膏转化α-半水石膏的特征及机理:实验与模拟

脱硫石膏的高效利用可以有效缓解一系列环境问题,变废为宝。本文利用二水石膏在含有微量无水硫酸钠的乙二醇水溶液中制备α-半水石膏,探究温度(94~98℃)、乙二醇体积分数(25%~35%)、硫酸钠浓度(0.1~0.3mol/L)对二水石膏向α-半水石膏脱水转化过程的α-半水石膏摩尔分数和动力学参数变化。研究发现,在乙二醇水溶液中,二水石膏向α-半水石膏脱水转化过程符合分散动力学模型。随着温度和乙二醇浓度的增加,动力学参数α基本保持不变,而参数β显著增加,导致活化熵△S*增大,进而导致能垒E_(a)降低,促进了二水石膏向α-半水石膏脱水转化。微量无水硫酸钠的添加,显著缩短了α-半水石膏的成核诱导时间。通过分子动力学模拟,增加硫酸钠的浓度,Na^(+)与SO_(4)^(2-)的配位数增加,扩散系数绝对差值∆D降低,从而导致配位能力增加,解耦能力降低。本研究对高效利用脱硫石膏、掌握其向α-半水石膏的转化特征具有重要意义。

半夏泻心汤治疗功能性消化不良的机制研究

目的 评估不同功能性消化不良(FD)造模方法的效果,并探讨半夏泻心汤对FD的治疗作用及潜在机制。方法 BALB/c小鼠随机分为空白组、碘乙酰胺组、洛哌丁胺组、夹尾组和食醋组。经过1周干预,观察各组小鼠状态并检测其胃肠动力、激素水平及病理变化,评估并确定一种较为理想的FD造模方法。造模后给予不同剂量半夏泻心汤进行干预,观察小鼠胃肠功能的改变,并通过免疫组化、ELISA、Western blot等实验方法研究相关蛋白表达情况。结果 对4种造模方法进行比较发现,碘乙酰胺组、洛哌丁胺组和食醋组小鼠与空白组相比体质量有所减轻;碘乙酰胺组和食醋组小鼠胃排空率及小肠推进率下降;夹尾组及食醋组小鼠血清中胃肠激素发生变化。最后评估碘乙酰胺法为最优的FD造模方法。给药结果显示半夏泻心汤对FD小鼠进食量及体质量无明显影响,中、高剂量可改善FD小鼠身体状态,提高其胃排空率与小肠推进率。免疫组织化学、ELISA、Western blot等实验结果证实,中、高剂量半夏泻心汤可显著降低FD小鼠十二指肠及血清内TNF-α及IL-6的表达水平。结论 碘乙酰胺法是一种更优的FD造模方法。半夏泻心汤可改善FD小鼠状态,提高胃肠动力,通过降低炎症因子分泌达到治疗FD的作用。

Lipopolysaccharide “Two-hit” Induced Refractory Hypoxemia Acute Respiratory Distress Model in Rats

To establish a stable and reliable model of refractory hypoxemia acute respiratory distress syndrome （ARDS） and examine its pathological mechanisms, a total of 144 healthy male Wistar rats were randomized into 4 groups： group Ⅰ （saline control group）, group Ⅱ （LPS intravenous ＂single-hit＂ group）, group Ⅲ （LPS intratracheal ＂single-hit＂ group） and Group IV （LPS ＂two-hit＂ group）. Rats were intravenously injected or intratracheally instilled with a large dose of LPS （10 mg/kg in 0.5 mL） to simulate a single attack of ARDS, or intraperitoneally injected with a small dose of LPS （1 mg/kg） followed by tracheal instillation with median dose of LPS （5 mg/kg） to establish a ＂two-hit＂ model. Rats in each group were monitored by arterial blood gas analysis and visual inspection for three consecutive days. Arterial blood gas values, lung wet/dry weight ratio and pathological pulmonary changes were analyzed to determine the effects of each ALI/ARDS model. Concentrations of TNF-α, IL-1 and IL-10 in the bronchoalveolar lavage fluid （BALF） and blood plasma were meastired by using enzyme-linked immunosorbent assays （ELISA）. Our resulsts showed that single LPS-stimulation, whether through intravenous injection or tracheal instillation, could only induce ALl and temporary hypoxemia in rats. A two-hit LPS stimulation induces prolonged hypoxemia and specific pulmonary injury in rats, and is therefore a more ideal approximation of ARDS in the animal model. The pathogenesis of LPS two-hit-induced ARDS is associated with an uncontrolled systemic inflammatory response and inflammatory injury. It is concluded that the rat ARDS model produced by our LPS two-hit method is more stable and reliable than previous models, and closer to the diagnostic criteria of ARDS, and better mimics the pathological process of ARDS.

机动目标跟踪α-jerk模型

本文针对jerk模型中人为设定参数α值的不合理性,对机动时间常数的倒数α进行建模,提出新的α-jerk模型,并给出相应的α-jerk滤波算法。该模型在估计目标状态的同时,能够实时估计参数α的值。仿真结果表明α-jerk模型比jerk模型收敛速度更快,状态估计更精确。

稳消颗粒对兔实验性动脉粥样硬化单核细胞趋化蛋白-1及肿瘤坏死因子α表达的影响

目的观察稳消颗粒对兔实验性动脉粥样硬化单核细胞趋化蛋白-1 (MCP-1)和肿瘤坏死因子α (TNF- α )表达的影响,探讨其抗动脉粥样硬化的作用机制。方法将36只健康新西兰大白兔随机分为正常组、模型组、稳消颗粒组、辛伐他汀组。除正常组外,其余各组给与高脂饮食,建立兔动脉粥样硬化模型,根据体重比例折算临床剂量给予相应药物治疗。药物治疗8周后处死动物,取腹主动脉根部行免疫组化染色法,观察兔腹主动脉根部动脉粥样硬化MCP-1、 TNF- α的表达。结果与模型组比较,稳消颗粒组、辛伐他汀组MCP-1、 TNF- α的表达均明显下调(P<0.05);稳消颗粒组与辛伐他汀组间比较,差异无统计学意义(P> 0.05)。结论稳消颗粒可抑制MCP-1、 TNF- α的表达,益于动脉粥样硬化斑块防治与稳定。

Proof of Concept for a Twin Prime Number Universe Using Set Theory

The Fine Structure Constant (eFSC) Model attempts to give a classical definition to a magical number that underlies much of quantum physics. The Fine Structure Constant (α) value equal to 137.03599206 represents a dimensionless constant that characterizes the strength of the electromagnetic (EM) interaction between subatomic charged particles. Python-generated property counts for the twin prime force F{139/137} show that the adjusted ratio gives a value of α = 137.036. This implies a mathematical framework underlying this constant is based on twin prime numbers and set theory. This study attempts to demonstrate a proof of concept that a hierarchy of fractional twin prime (αII) forces replicates the quantum nature of the universe and is aligned with the Standard Model of Particle Physics. An expanded eFSC Model demonstrates that twin prime forces and their property sets are mathematically viable substitutes for nuclear reactions, as demonstrated for the Beta-minus decay of neutrons into protons. Most significantly, the positive and negative prime numbers define these nuclear reactants and products as positive or negatively charged ions. Furthermore, the eFSC Model provides new insights regarding the hierarchy of EM forces underlying the quantum nature of the universe.

应用时间序列分析法对太湖叶绿素-a含量的动态研究

叶绿素-a是湖泊浮游植物现存量的重要指标,其含量能反映水中浮游植物的丰度和变化规律。研究叶绿素含量的动态变化,可以有效防止、监控湖泊富营养化的发生。以太湖为研究对象,根据其营养水平进行分区,使得不同区域内叶绿素的浓度不同,而同一区域内浓度大体一致,然后利用地理信息系统技术对每个区域内未采样点的叶绿素浓度进行插值,取区域内所有栅格的平均值作为其最终浓度。应用时间序列分析方法对太湖1998—2004年每月的叶绿素含量进行动态模拟,建立各湖区的预测模型。结果表明,中营养区Ⅰ符合MA(1)模型,轻富营养区Ⅱ和中富营养区Ⅲ符合AR(1)模型,富营养区Ⅳ符合MA(5)模型,重富营养区Ⅴ符合AR(6)模型。由此预测出2005年各湖区总叶绿素的含量,经前10个月实测数据的验证说明,所建模型在一定程度上能反映太湖各区域叶绿素浓度的变化。

2株桑树内生菌发酵产物的降血糖作用

通过体外α-葡萄糖苷酶抑制试验和糖尿病模型小鼠动物试验,检验桑树内生菌菌株Stenotrophomonas maltophilia Y1和Micrococcus luteus Y2发酵产物的降血糖作用。结果表明,Y1和Y2菌株发酵液提取物对α-葡萄糖苷酶均具有显著的体外抑制作用,并呈现一定的剂量依赖性,半数抑制浓度(IC50)分别为2 307.56 mg/L和111.58 mg/L,在试验最大剂量下的抑制率分别达到59.17%和69.21%,均高于对照药物拜糖平(抑制率为53.06%)。动物试验表明,饲喂Y1菌株发酵液浓缩产物的糖尿病模型小鼠的空腹血糖(FBG)值和餐后血糖(PBG)值均低于模型组,分别存在显著和极显著差异,而对正常小鼠的血糖无明显影响,也未表现出毒副作用;调查饲喂发酵产物后糖尿病模型小鼠的体质量、进食量、饮水量、排尿量等指标,均得到明显改善。试验结果显示,2株桑树内生菌菌株的发酵液提取物均表现出与1-脱氧野尻霉素(DNJ)相同的体外抑制α-葡萄糖苷酶活性的作用,Y1菌株发酵产物表现出与DNJ相同的降低糖尿病模型小鼠血糖及改善糖尿病症状的作用特点。

新陈代谢GM(1，1，α)模型在数控机床热误差建模中的应用

针对数控机床热误差产生机理及变化规律的复杂性,提出了一种新的灰色系统模型,并将其应用于热误差建模分析中。分析了传统GM(1,1)模型的不足之处,在新陈代谢GM(1,1)模型的基础上,结合微粒群算法,提出了一种新的新陈代谢GM(1,1,α)模型。为提高建模精度,该模型在建模过程中及时去除旧的信息,加入新信息,并使用微粒群算法求解参数α以获取α的全局最优值。最后,针对某数控机床热误差序列,分别使用GM(1,1)模型、新陈代谢GM(1,1)模型和新陈代谢GM(1,1,α)模型进行建模和预测,结果表明新陈代谢GM(1,1,α)模型的建模效果最好。

拟南芥转酮醇酶蛋白AtTKL1的同源建模及与α-三联噻吩结合作用分析

以玉米转酮醇酶(1ITZ)的晶体结构为模板,对拟南芥转酮醇酶(At TKL1)的三维结构进行模拟和优化.利用生物信息学方法,确定其氨基酸结合位点为His143,Gly234,Asn263,Arg434,Ser461,Gln488,Phe515,His539,Asp547和Arg598,催化氨基酸位点为His103和His340.通过分子模拟确定α-三联噻吩与At TKL1的活性口袋可有效结合,且At TKL1的催化位点和结合位点为其与α-三联噻吩结合的关键位点.利用荧光猝灭光谱技术确定At TKL1与α-三联噻吩之间存在结合作用;酶活力检测结果表明加入α-三联噻吩后转酮醇酶蛋白的活性降低,进一步验证了At TKL1与α-三联噻吩之间的相互作用.

Logistic回归模型拟合临床因素、营养状况、炎症指标对维持性血液透析患者并发肺部感染的预测价值

目的探究Logistic回归模型拟合临床因素、营养状况、炎症指标对维持性血液透析患者并发肺部感染的预测价值。方法选取2018年8月—2020年8月维持性血液透析152例作为研究对象,根据是否并发肺部感染分为感染组32例与未感染组120例。比较2组临床因素、营养状况指标[白蛋白(Alb)、前白蛋白(PA)、血红蛋白(Hb)]、炎症指标[C反应蛋白(CRP)、肿瘤坏死因子-α(TNF-α)]水平,分析营养指标与炎症指标相关性,采用Logistic回归模型拟合临床因素、营养状况、炎症指标生成联合预测因子,评价各指标与联合预测因子对维持性血液透析并发肺部感染的预测价值,并进行个体值预测。结果感染组年龄≥60岁、合并糖尿病、平均每周透析时间≥12 h及血清CRP、TNF-α水平高于未感染组,血清Alb、PA、Hb水平低于未感染组(P<0.05,P<0.01)。血清Alb、PA、Hb与CRP、TNF-α呈负相关(P<0.01)。年龄、合并糖尿病、平均每周透析时间、血清CRP、TNF-α是维持性血液透析并发肺部感染的独立危险因素,血清Alb、PA、Hb是维持性血液透析并发肺部感染的独立保护因素(P<0.01)。联合预测因子预测维持性血液透析并发肺部感染的预测价值高于各临床因素、营养状况、炎症指标单独预测;随机抽取1例患者,将各自变量代入概率预测方程得到概率值P=0.162,小于最佳临界值,故在预测准确率为82.24%的条件下,该患者在维持性血液透析期间不会并发感染。结论Logistic回归模型拟合临床因素、营养状况、炎症指标生成的联合预测因子对维持性血液透析患者并发肺部感染具有可靠预测价值,能为临床及早防治提供可靠依据。

肿瘤坏死因子-α在脓毒症大鼠心肌损害中的表达及作用机制

目的探讨肿瘤坏死因子(TNF)-α在脓毒症大鼠心肌损害中的表达及其作用机制。方法将40只1月龄的健康清洁级雄性Wistar大鼠随机分为脓毒症组20只(盲肠结扎穿刺术脓毒症造模)、对照组20只(假手术仅开腹翻动盲肠),应用免疫组织化学法检测两组心肌中TNF-α的表达强度。电镜观察心肌损伤的病理变化,进行病理学分级和白细胞浸润分级。分析损伤心肌中TNF-α表达强度与病理分级、白细胞浸润分级的关系。结果 TNF-α在脓毒症组心肌中的表达强度明显大于对照组(P<0.01);脓毒症组心肌病理分级及白细胞浸润分级明显高于对照组(P<0.01);脓毒症组心肌中TNF-α表达的强弱与病理分级和白细胞浸润分级呈正相关。结论 TNF-α与脓毒症心肌损害密切相关,其介导的炎症在心肌损害的发生发展过程中起着重要的作用。