高密度聚乙烯三维网状纳微米纤维的强伸性能

为实现高密度聚乙烯三维网状纳微米纤维(PENFs)的自主化规模化生产,以高密度聚乙烯和二氯甲烷为原料,通过高压闪喷纺丝设备成功制备了性能优异的PENFs,采用响应面法对纺丝过程中各工艺参数进行优化,并对其力学性能和耐候性能进行分析。结果表明:PENFs的最佳制备工艺条件为纺丝温度176.3℃、纺丝压力8.6 MPa、纺丝溶液质量分数8.0%,此时制得的PENFs的断裂强度和断裂伸长率分别可达到29.1 cN/dtex和99.9%,优于芳纶和涤纶等常规纤维;定伸长和定载荷条件下,PENFs的弹性回复能力随着拉伸次数和载荷的增加而逐渐降低,拉伸伸长为5%时PENFs纤维的弹性回复率可达到92.8%且拉伸10次后降低至75.5%,拉伸载荷为1.2 N时PENFs纤维的弹性回复率为84.6%;放置在室外20 d内PENFs纤维的强伸性能损失较小,30 d后断裂强度和断裂伸长率明显降低,但纤维外貌并无明显变化。

高湿度下具有荧光指示功能的PET复合膜的制备与性能

为了制备出能在高湿度、易结雾环境下可持续发光的薄膜,以聚对苯二甲酸乙二醇酯(PET)膜为基底,将具有优异疏水功能的新型稀土发光配合物和聚甲基丙烯酸甲酯(PMMA)均匀分散制成发光涂覆液,通过涂覆刮膜技术,制备出PET-PMMA发光复合膜,并对其进行测试表征。荧光分光光度计和共聚焦显微镜测试的结果表明:发光材料占聚合物PMMA的质量分数为1.50%时所制备的PET发光膜具有良好的表面均匀性和最佳的荧光性能,荧光强度可达到9979 a.u.,在不同激发波长下PET-PMMA发光复合膜均可以显现出发光材料中Eu3+的特征荧光发射峰;测得发光复合膜的最佳紫外激发波长为350 nm,在最佳激发波长下发光复合膜具有较好的色纯度;通过对比发光复合膜浸泡在水溶液7 d内每天的荧光强度值,发现在发光材料仅有1.50%的前提下,样品的荧光强度损失仅有5%,这表明所制备的发光复合膜遇水易猝灭的弊端得到极大改善,这为PET农膜在潮湿、易结雾环境下实现长期稳定的荧光指示功能提供了重要基础。

具有光致变色功能的PA6纳微米纤维的制备与性能

为制备具有光致变色功能的纳微米纤维,以萘并吡喃(NA)为变色单元,以甲基丙烯酸甲酯(MMA)为聚合物基质单体,以二氧化硅(SiO_(2))为包覆层,制备了光致变色纳微米微球PMMA/NA@SiO_(2),然后将PMMA/NA@SiO_(2)纳微米微球引入到尼龙6的静电纺丝溶液中,通过对静电纺丝过程中的各工艺参数的优化,对PA6的基本形貌进行了在线调控,成功制备了直径分布较均匀的PA6纳微米变色纤维。场发射扫描电镜和紫外可见光分光光度计的测试结果表明:PMMA/NA@SiO_(2)的直径范围在100~210 nm之间;在PMMA/NA@SiO_(2)质量分数小于10%时,纤维样品的形貌无明显变化,变色性能随添加的变色材料的增加而增强,所制备的样品变色性能和纤维形貌最好,在紫外光照射后会呈现出较好的变色性能和耐疲劳性;通过紫外灯照射发现,相对于λ=365 nm的紫外光,λ=254 nm的紫外光对该光致变色纳微米纤维的变色性能影响较大。

C反应蛋白和脂蛋白a与冠状动脉狭窄程度的相关性研究

目的探讨不同炎症C反应蛋白(CRP)水平下Lp(a)与急性冠脉综合征(acute coronary syndrome,ACS)患者冠脉狭窄的相关性。方法本研究共纳入429例ACS患者,采用高灵敏度比浊法和酶联免疫吸附法分别测定CRP和Lp(a)的表达水平,将CRP≥10 mg/L定义为CRP+,CRP<10 mg/L定义为CRP-;Lp(a)≥300 ng/mL定义为Lp(a)+,Lp(a)<300 ng/mL定义为Lp(a)-。所有纳入的患者根据检测结果分为4组,包括CRP-/Lp(a)-、CRP-/Lp(a)+、CRP+/Lp(a)-、CRP+/Lp(a)+;冠状动脉狭窄程度通过冠状动脉造影评估,使用Gensini评分计算狭窄严重程度;采用多变量Logistic回归模型分析CRP和Lp(a)水平联合与冠状动脉狭窄程度之间的关系。结果年龄、吸烟、高血压病、糖尿病、Gensini评分四组存在显著差异(P<0.05),CRP-时,多因素线性回归分析模型分析发现年龄、吸烟以及糖尿病是Gensini评分的独立危险因素(P<0.05);CRP+时,多因素线性回归分析模型分析发现年龄、吸烟、糖尿病以及Lp(a)+是Gensini评分的独立危险因素(P<0.05)。四组患者中,CRP-/Lp(a)-与冠状动脉狭窄程度的相关性最低,95%CI:0.111~8.520;CRP+/Lp(a)+组与冠状动脉狭窄程度的相关性最高,(95%CI:4.674~21.230)。结论CRP+/Lp(a)+与冠状动脉狭窄程度的相关性比其他任何一组均更高,因此提示高炎症水平的人群中降低Lp(a)可能获益最大。

免疫检查点抑制剂治疗恶性肿瘤的群体药代动力学研究进展

以免疫检查点抑制剂(ICIs)为代表的靶向单克隆抗体类抗肿瘤药物可阻断ICIs分子与其配体的结合,从而通过增强T细胞免疫活性促进肿瘤细胞清除,这在改善几种预后不良的恶性肿瘤总生存率方面显示出显著的临床效果。群体药代动力学(PPK)可表征药物在特定人群中的药代动力学(PK)特征,为个体化用药提供参考。目前关于ICIs的PPK研究报道日益增多。本文综述常见抗肿瘤ICIs类药物的PPK研究进展,列举各类药物的PPK模型结构参数及其协变量,并总结药物是否需要根据相关影响因素进行给药方案的调整,以期为临床合理使用ICIs药物及其药动-药效学(PK-PD)研究提供参考。

Resilience and response:Unveiling the impacts of extreme droughts on forests through integrated dendrochronological and remote sensing analyses

Extreme droughts are anticipated to have detrimental impacts on forest ecosystems,especially in water-limited regions,due to the influence of climate change.However,considerable uncertainty remains regarding the patterns in species-specific responses to extreme droughts.Here,we conducted a study integrating dendrochronology and remote sensing methods to investigate the mosaic-distributed maple-oak(native)natural forests and poplar plantations(introduced)in the Horqin Sandy Land,Northeast China.We assessed the impacts of extreme droughts on tree performances by measuring interannual variations in radial growth and vegetation index.The results showed that precipitation and self-calibrated palmer drought severity index(scPDSI)are the major factors influencing tree-ring width index(RWI)and normalized difference vegetation index(NDVI).The severe droughts between 2000 and 2004 resulted in reduced RWI in the three studied tree species as well as led to NDVI reductions in both the maple-oak natural forests and the poplar plantations.The RWI reached the nadir during the2000-2004 severe droughts and remained at low levels two years after the severe drought,creating a legacy effect.In contrast to the lack of significant correlation between RWI and scPDSI,NDVI exhibited a significant positive correlation with scPDSI indicating the greater sensitivity of canopy performance to droughts than radial growth.Furthermore,interspecific differences in RWI and NDVI responses were observed,with the fast-growing poplar species experiencing a more significant RWI decrease and more negative NDVI anomaly during severe droughts than native species,highlighting the species-specific trade-offs between drought resilience and growth rate.This study emphasizes the importance of combining tree-level radial growth with landscape-scale canopy remote sensing to understand forest resilience and response.Our study improves our understanding of forest responses to extreme drought and highlights species differences in climate responses,offering crucial insights for optimizing species selection in sustainable afforestation and forest management in water-limited regions under the influence of climate change.

Fault Identification for Shear-Type Structures Using Low-Frequency Vibration Modes

Shear-type structures are common structural forms in industrial and civil buildings,such as concrete and steel frame structures.Fault diagnosis of shear-type structures is an important topic to ensure the normal use of structures.The main drawback of existing damage assessment methods is that they require accurate structural finite element models for damage assessment.However,for many shear-type structures,it is difficult to obtain accurate FEM.In order to avoid finite elementmodeling,amodel-freemethod for diagnosing shear structure defects is developed in this paper.This method only needs to measure a few low-order vibration modes of the structure.The proposed defect diagnosis method is divided into two stages.In the first stage,the location of defects in the structure is determined based on the difference between the virtual displacements derived from the dynamic flexibility matrices before and after damage.In the second stage,damage severity is evaluated based on an improved frequency sensitivity equation.Themain innovations of this method lie in two aspects.The first innovation is the development of a virtual displacement difference method for determining the location of damage in the shear structure.The second is to improve the existing frequency sensitivity equation to calculate the damage degree without constructing the finite elementmodel.Thismethod has been verified on a numerical example of a 22-story shear frame structure and an experimental example of a three-story steel shear structure.Based on numerical analysis and experimental data validation,it is shown that this method only needs to use the low-order modes of structural vibration to diagnose the defect location and damage degree,and does not require finite element modeling.The proposed method should be a very simple and practical defect diagnosis technique in engineering practice.

基于SVG的综合功率调节系统

随着电力电子技术的快速发展,H桥级联型静止无功发生器SVG控制系统,因每个功率模块承受的电压低、开关损耗小、谐波电压小、等效开关频率高等特点,通过实现不同的控制策略,广泛应用于钢厂的无功补偿、谐波补偿、新能源场站的电压控制、功率因数控制、电网暂态高低电压穿越等,同时SVG多机并联补偿,及SVG+FC混合并联实现补偿容量的扩充的拓扑结构,实现特征次谐波的滤除和无功补偿的快速响应,也是广泛应用的拓扑结构。通过仿真结果验证各补偿模式、控制策略的有效性与实用性。

Detection of apoptosis induced by new type gosling viral enteritis virus in vitro through fluorescein annexin V-FITC/PI double labeling

AIM: To achieve a better understanding of the pathogenesis of new type gosling viral enteritis virus (NGVEV) and the relationship between NGVEV and host cells. METHODS: The apoptosis of duck embryo fibroblasts (DEF) induced by NGVEV was investigated by fluorescence-activated cell sorter (FACS) and fluorescence microscope after the cells were stained with Annexin V-FITC and propidium iodide (PI). RESULTS: By staining cells with a combination of fluorescein annexin V-FITC and PI, it is possible to distinguish and quantitatively analyze non-apoptotic cells (Annexin V-FITC negative/PI negative), early apoptotic cells (Annexin V-FITC positive/PI negative), late apoptotic/necrotic cells (Annexin V-FITC positive/ PI positive) and dead cells (Annexin V-FITC negative/PI positive) through flow cytometry and fluorescence microscope. The percentage of apoptotic cells increased with the incubation time and reached a maximum at 120 h after infection, while the percentage of non- apoptotic cells decreased.

一种高压SVG用于容性负载下的谐波补偿方法

高压供电系统电缆化趋势明显,尤其城市供电网及新能源场站,高压电缆存在较大的寄生电容,针对容性非线性负载,常规高压SVG采用电流补偿模式进行谐波补偿时存在不稳定现象,引起系统谐振和谐波放大。本文提出了一种基于阻抗控制的谐波补偿策略,仿真结果验证了控制策略的有效性。

机载计算机故障诊断技术研究

近年来,机载计算机飞速发展大大促进了飞机的功能及性能提升,但同时,机载计算机的故障排查问题也越来越复杂。基于此,总结归纳了机载计算机故障的排查流程及排查方法,对提升机载计算机故障排查效率具有一定的参考价值。

基于 ε -EGA 多准则调整的舰船维修资源配置决策方法与应用

为了提高舰船维修资源配置的科学性、有效性,针对舰船维修目标提出维修战斗力定义,统筹考虑了舰船维修资源配置过程中的财力、人力、物力和技术资源对于资源配置的影响,构建了舰船维修资源配置模型。求解方法上,以军事效益(维修战斗力)最大和维修成本最小为优化目标,将舰船维修资源配置问题转化为混合整数非线性规划模型的多目标寻优问题。在标准遗传算法(SGA)基础上,融合ε约束准则和精英保留策略,构建一种新型ε-EGA的多准则调整算法,搜索获取满意的Pareto解集与前沿。结合企业H的年度舰船维修任务实际进行实证检验,提高优化配置模型结论的科学性,增强模型与实际情况的吻合度。结果表明,ε-EGA多准则调整算法具有良好的适用性和延展性,计算速度快,方案优化度高,而维修资源配置模型对于其他建造工程行业的资源调度、计划安排等工作开展,也具有较强的借鉴意义。

Suppression of renal cell proliferation, induction of apoptosis and cell cycle arrest: Cytotoxicity of vanadium in broilers

The aims of this study were to clarify the effects of high vanadium on the renal cell cycle and apoptosis in broilers. 420 one-day-old avian broilers were divided into six groups and fed on a control diet (vanadium 0.073 mg/kg), and five high vanadium diets (vanadium 5 mg/kg, high vanadium group I;15 mg/kg, high vanadium group II;30 mg/kg, high vanadium group III;45 mg/kg, high vanadium group IV;60 mg/kg, high vanadium group V) throughout the experimental period of 42 days. As tested by flow cytometry, the percentage of apoptotic renal cells was increased in high vanadium group II, III, IV and V when compared with that of control group. The Proliferating index (PI) of renal cell and the ratio of S, G2 + M phase cells were markedly decreased and population of G0/G1 cells was increased in high vanadium group II, III, IV and V. The results showed that dietary vanadium in excess of 15 mg/kg was toxic to kidney by the renal cells cycle arrest and increased apoptosis, which caused the growth depression of the kidney in broilers.

Effects of High Dietary Fluoride on Serum Biochemistry and Oxidative Stress Parameters in Broiler Chickens

The aim of this study was to investigate the effects of high dietary fluoride (F) on serum biochemistry and oxidative damage in broiler chickens. 280 one-day-old healthy avian broiler chickens were randomly allotted into four equal groups and fed with a corn-soybean basal diet containing 22.6 mg·F/kg (control group) or same basal diets supplemented with 400, 800, and 1200 mg·F/kg (high F groups I, II, and III) in the form of sodium fluoride for 42 days. At 42 days of age, the serum F content was markedly higher in the three high F groups than that in the control group. From 28 to 42 days of age, the contents of serum total protein (TP) and albumin (ALB) were significantly lower in the three high F groups. From 14 to 42 days of age, the activities of alkaline phosphatase (ALP), alanine aminotransferase (ALT) and the creatinine (Crea) contents in the serum showed a marked increase in the three high F groups;aspartate aminotransferase (AST) activity and uric acid (Ua) content were significantly increased, and a significant increase in the content of malondialdehyde (MDA) along with marked decreases in the activities of total superoxide dismutase (T-SOD), glutathione peroxidase (GSH-Px), catalase (CAT), the glutathione (GSH) content and the ability to inhibit hydroxyl radical were observed in the high F groups II and III. In conclusion, F has accumulated in the blood circulatory system and dietary F in the range of 800 - 1200 mg/kg could significantly induce abnormalities of bone, liver and kidney, inhibit the synthesis of protein, enhance lipid peroxidation and disturb the antioxidative system of broiler chickens.

PET发光复合膜的制备工艺与荧光性能优化

为制备具有良好光致发光功能的聚对苯二甲酸乙二醇酯(PET)发光复合膜,以PET薄膜为基材,通过物理喷涂技术将荧光强度较好的有机稀土发光材料均匀分布在PET膜表面,制备PET发光膜;在PET发光膜表面引入不同聚合物的防护功能层,制备PET发光复合膜,并进行荧光性能测试与表征。结果表明:发光喷涂溶液质量分数为1.50%时所制备的PET发光膜具有最佳的荧光性能,且发光材料在膜表面分散均匀;选用PVDF为防护功能层所制备的PET-PVDF发光复合膜荧光强度最高,达3158 a.u.,而且在不同激发波长下PETPVDF发光复合膜均可以显现出发光材料中Eu^(3+)的特征荧光发射峰;PET-PVDF发光复合膜的最佳紫外激发波长为301 nm,在最佳激发波长下PET-PVDF发光复合膜具有较好的色纯度,可以显现出靓丽的红光。

Investigation of the serum oxidative stress in broilers fed on diets supplemented with nickel chloride

The purpose of this study was to investigate the serum oxidative stress induced by dietary nickel chloride (NiCl2) in broilers. A total of 240 one-day-old avian broilers were divided into four groups and fed on a cornsoybean basal diet as control diet or the same basal diet supplemented with 300 mg/kg, 600 mg/kg and 900 mg/kg NiCl2. During the experimental period of 42 days, oxidative stress parameters were determined for both control and experimental groups. The results showed that malondialdehyde (MDA) content was significantly higher (p < 0.05 or p < 0.01) in the 300 mg/kg, 600 mg/kg and 900 mg/kg groups than that in the control group. In contrast, the activities of superoxide dismutase (SOD), catalase (CAT) and glutathione per- oxidase (GSH-Px), and the ability to inhibit hydroxy radical, and glutathione hormone (GSH) content were significantly decreased (p < 0.05 or p < 0.01) in the 300 mg/kg, 600 mg/kg and 900 mg/kg groups in comparison with those of the control group. It was concluded that dietary NiCl2 in excess of 300 mg/kg could cause oxidative stress, which could finally impaired the antioxidant function in broilers.

‘砧茄一号’砧木新品种特性及其对嫁接番茄农艺性状的影响

生产上,嫁接是提高番茄品质和产量的有效措施之一.为了创制抗性强、生长势旺的番茄砧木,以‘砧茄一号’为试验砧木,以番茄上应用最广泛的‘托鲁巴姆’为对照砧木,分别与4种番茄品种进行嫁接,比较两者作为砧木对番茄生长发育、产量和品质等的影响.结果表明:相比于‘托鲁巴姆’,‘砧茄一号’种子发芽显著提前4 d,幼苗的平均株高显著高约2 cm.幼苗的第1,2,3片真叶完整展开耗时缩短8 d,8 d和6 d,幼苗主根显著长约1.2 cm.在干旱胁迫和盐胁迫下,经赤霉素和纯水预处理的‘砧茄一号’种子发芽率分别为100%和75%,87.5%和100%,而‘托鲁巴姆’在两种胁迫下,两种预处理种子的发芽率均为0.与‘托鲁巴姆’砧木番茄相比,‘砧茄一号’砧木番茄果实中的可溶性固形物、可溶性糖和维生素C质量分数呈上升趋势,‘砧茄一号’砧木番茄植株的单果质量、单穗果数、单株结果数和单株产量大多也呈上升趋势.综上表明,采用‘砧茄一号’为砧木能克服‘托鲁巴姆’为砧木时存在的发芽慢、长势弱的局限,同时可显著提高番茄的产量和品质,即‘砧茄一号’可作为番茄嫁接栽培的优良砧木,对高品质番茄的生产具有重要意义.

汽车设计课程线上混合式教学模式改革与实践

汽车设计课程理论性和综合性强,原有课堂教学缺乏有效的课前学习引导,线下教学受疫情影响无法开展。基于“超星学习通+腾讯会议直播”的汽车设计课程线上混合式教学模式改革与实践,通过课前导学、专题讨论、章节测试、学情统计和线上直播教学互动,实现线上导学平台和直播教学的结合,确保课程线上教学质量。

无人装备创新实践俱乐部教学建设初探

为适应新形势下高等教育变革的趋势,满足无人装备工程专业创新型和复合型人才的培养需求,海军工程大学舰船与海洋学院拟成立无人装备创新实践俱乐部,围绕无人装备设计制造、模块组装、性能调试、操控指挥、任务策略等内容,加强学员对无人装备专业知识的理解与应用,提高学员的创新能力和实践能力,致力于打造俱乐部服务教学的改革基地、无人装备工程专业的人才培养拓展基地。

Recent developments in application of single-cell RNA sequencing in the tumour immune microenvironment and cancer therapy

The advent of single-cell RNA sequencing(scRNA-seq)has provided insight into the tumour immune microenvironment(TIME).This review focuses on the application of scRNA-seq in investigation of the TIME.Over time,scRNA-seq methods have evolved,and components of the TIME have been deciphered with high resolution.In this review,we first introduced the principle of scRNA-seq and compared different sequencing approaches.Novel cell types in the TIME,a continuous transitional state,and mutual intercommunication among TIME components present potential targets for prognosis prediction and treatment in cancer.Thus,we concluded novel cell clusters of cancerassociated fibroblasts(CAFs),T cells,tumour-associated macrophages(TAMs)and dendritic cells(DCs)discovered after the application of scRNA-seq in TIME.We also proposed the development of TAMs and exhausted T cells,as well as the possible targets to interrupt the process.In addition,the therapeutic interventions based on cellular interactions in TIME were also summarized.For decades,quantification of the TIME components has been adopted in clinical practice to predict patient survival and response to therapy and is expected to play an important role in the precise treatment of cancer.Summarizing the current findings,we believe that advances in technology and wide application of single-cell analysis can lead to the discovery of novel perspectives on cancer therapy,which can subsequently be implemented in the clinic.Finally,we propose some future directions in the field of TIME studies that can be aided by scRNA-seq technology.