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关键词： Complementary graph   Forbidden induced subgraph   Graph spectrum   Second largest eigenvalue  

摘要： By extending the main result of [European J. Combin., 97 (2021), 103385], we determine all connected claw-free graphs whose second largest eigenvalue does not exceed 1, where a claw is the star $K_{1,3}$. In contrast to the existing results on graphs with the same spectral property, our approach introduces a technique that systematically analyses complementary graphs of graphs under consideration.

关键词： 环境内分泌干扰物   1型糖尿病   发病机制   风险因素   双酚A   全氟化合物   邻苯二甲酸酯类化合物   农药  

摘要： 背景:环境内分泌干扰物作为一类广泛存在于环境中的外源性化合物,可通过干扰内分泌系统功能参与多种疾病的发生。近年来,环境内分泌干扰物暴露与1型糖尿病发病风险的关联性逐渐成为研究热点,但其具体机制尚未明确。目的:综述环境内分泌干扰物与1型糖尿病之间的流行病学研究、动物实验研究及相关机制研究进展。方法:以“endocrine disrupting chemicals,EDCs,type 1 diabetes,T1DM”为英文检索词,以“环境内分泌干扰物,1型糖尿病”为中文检索词,检索PubMed、CNKI数据库2000年1月至2025年1月发表的文献,最终纳入55篇文献进行归纳分析。结果与结论:双酚A、农药、重金属等典型环境内分泌干扰物可通过诱导免疫紊乱、激活氧化应激及表观遗传调控等途径促进1型糖尿病发生。现有研究存在暴露评估方法不统一、剂量-效应关系不明确及人群异质性等问题。未来需聚焦关键暴露窗口期识别和多组学整合研究,为1型糖尿病的预防提供新策略。

关键词： 纤维蛋白1基因   甲基化   阿尔茨海默病   dKO小鼠   DTG小鼠   β-淀粉样蛋白  

摘要： 背景:阿尔茨海默病的病理主要表现为β-淀粉样蛋白异常沉积及tau蛋白神经纤维缠结,临床上常用的药物只能控制部分症状,尽管也做出了巨大努力来开发新的治疗阿尔茨海默病的药物,如针对β-淀粉样蛋白的靶向免疫疗法和β分泌酶抑制剂,但目前的临床试验并没有取得成功。目的:观察纤维蛋白1基因在无β-淀粉样蛋白异常沉积的阿尔茨海默病PSEN1/PSEN2双基因敲除小鼠(dKO)及具有β-淀粉样蛋白异常沉积的APP/PS1双转基因小鼠(DTG)海马组织中的甲基化改变情况,探寻阿尔茨海默病非β-淀粉样蛋白异常沉积的相关机制及潜在靶标。方法:分别选取9只雌性7月龄(早期阿尔茨海默病)及12月龄(中期阿尔茨海默病)dKO小鼠海马组织及同龄野生型小鼠作为对照,应用表观亚硫酸盐测序方法筛选出异常甲基化改变基因纤维蛋白1;运用亚硫酸氢盐单基因甲基化测序方法验证纤维蛋白1基因在中期dKO小鼠海马组织中甲基化状态的改变;利用RT-PCR及Western blot方法分别检测早期及中期dKO小鼠纤维蛋白1基因mRNA和蛋白表达水平,同时检测12月龄DTG小鼠的纤维蛋白1基因mRNA和蛋白表达水平;最后对比检测dKO小鼠和DTG小鼠纤维蛋白1和β-淀粉样蛋白的表达水平,同龄雌性野生型小鼠作为对照。结果与结论:①表观亚硫酸盐测序显示中期阿尔茨海默病dKO小鼠海马组织纤维蛋白1基因低甲基化且具有统计学意义(P<0.05),早期虽然也呈低甲基化,但与野生型小鼠比无显著性差异(P>0.05);亚硫酸氢盐单基因甲基化测序PCR检测结果同样验证了阿尔茨海默病中期dKO小鼠海马组织中纤维蛋白1基因呈现异常低甲基化状态;②早期阿尔茨海默病dKO小鼠的纤维蛋白1基因的mRNA及蛋白表达水平与同龄野生型小鼠比无差异(P>0.05,P>0.05);中期阿尔茨海默病dKO小鼠纤维蛋白1的mRNA水平及蛋白表达明显高于同龄野生型小鼠(t=5.336,P<0.01;t=8.985,P<0.01),而中期阿尔茨海默病DTG小鼠纤维蛋白1的mRNA及蛋白表达水平同样显著高于同龄野生型小鼠(t=4.151,P<0.01;t=8.392,P<0.01),但2个阿尔茨海默病动物模型中期的纤维蛋白1 mRNA及蛋白表达水平无差异(P>0.05,P>0.05);③中期阿尔茨海默病dKO小鼠纤维蛋白1和β-淀粉样蛋白的蛋白表达水平之间无差异(P>0.05),而中期DTG小鼠纤维蛋白1和β-淀粉样蛋白的蛋白表达水平之间差异有显著性意义(t=6.348,P<0.01),表明纤维蛋白1基因除了在具有β-淀粉样蛋白沉积的DTG小鼠模型发挥作用外,在无β-淀粉样蛋白沉积的dKO小鼠中同样发挥作用,提示阿尔茨海默病的发生发展中可能还存在纤维蛋白1基因相关的作用机制;④纤维蛋白1基因甲基化改变可能参与dKO小鼠年龄依赖性神经退行性变,并且可能同时参与阿尔茨海默病的β-淀粉样蛋白异常沉积与非β-淀粉样蛋白沉积机制,为探究非β-淀粉样蛋白沉积相关机制及新的潜在靶标提供了新的思路与证据;纤维蛋白1作为一种衰老相关因素和新的靶标具有广阔的应用前景。

关键词： 2D/2D heterostructures   Bidirectional electron transfer   Metal-organic frameworks   Molybdenum disulfide   Overall water splitting   Oxygen evolution reaction  

摘要： The sluggish kinetics of the oxygen evolution reaction (OER) remains a major bottleneck for efficient water splitting. Despite being promising alkaline OER catalysts, most two-dimensional (2D) metal-organic frameworks (MOFs) undego kinetically uncontrolled reconstruction into metal (oxy)hydroxides (MOOH), leading to insufficient intrinsic activity and poor stability. More importantly, the electronic modulation of the pre-catalysts is crucial to forming highly active and stable MOOH for steering the reconstruction kinetics. Herein, a heterojunction pre-catalyst is fabricated by in situ growth of FeNiCo-BDC (FNC) on 1 T-phase-dominated MoS₂ nanosheets supported by carbon cloth (CC) (FNC@MoS₂/CC). Comprehensive experimental and theoretical analyses reveal that the pre-catalyst possesses an advantageous electronic structure, featuring interfacial electron-rich metal sites induced by bidirectional electron transfe. This leads to a downshifted d-band center position, accelerated charge transfer, and optimized adsorption/desorption of OER intermediates. Crucially, in situ investigations demonsreate that this modulated electron regulation of FNC@MoS₂/CC controls the kinetics of electrochemical reconstruction, thus facilitating the transformation toward a highly active and ctive and stable catalytic MOOH@MoS₂. Consequensely, FNC@MoS₂/CC achieves an ultralow overpotential of 188 mV at 10 mA cm⁻² and outstanding stability over 100 h for OER. Furthermore, it enables efficient overall water splitting with a low cell potential of 1.539 V at 10 mA cm⁻². Notably, in an 25 °C anion-exchange-membrane electrolyzer, a FNC@MoS₂/CC (+,-) couple displays 500 mA cm⁻² at only 1.87 V and operates stably over 200 h. This work highlights that engineering pre-catalysts to steer dynamic surface reconstruction is an pivotal strategy for advanced OER electrocatalysis.

关键词： Bioinformatics   Cyclophosphamide   Ferulic Acid   Hesperidin   Keap1/Nrf2/HO-1 Pathway   Nephrotoxicity  

摘要： Although cyclophosphamide (CYP) is still a mainstay of cancer chemotherapy; yet, its clinical utility is often undermined by nephrotoxicity.

关键词： 替西帕肽   阿尔茨海默病   网络药理学   血管紧张素Ⅱ2型受体   蛋白互作网络   突触功能  

摘要： 背景:胰高血糖素样肽1受体激动剂作为神经退行性疾病治疗的新型候选药物,已在阿尔茨海默病临床研究中取得突破性进展,其中索马鲁肽等药物已推进至Ⅲ期临床试验阶段。然而,目前对于该类药物神经保护效应的分子作用机制仍存在显著的知识缺口。目的:创新性地整合多组学分析技术与网络药理学方法,系统解析阿尔茨海默病病理相关基因谱系与替西帕肽潜在作用靶点的交集网络,鉴定关键调控基因,并通过体内外实验验证其分子机制。方法:采用多维度研究策略:①基于DisGeNET数据库(整合了多种疾病相关的基因组学数据库)构建阿尔茨海默病差异表达基因谱。②通过PubChem数据库(小分子生物活性数据库)获取替西帕肽结构并筛选潜在靶点。③应用DAVID数据库开展GO功能注释及KEGG通路富集分析。④结合STRING数据库与Cytoscape 3.9.1构建蛋白质互作网络,经拓扑网络分析筛选关键基因。⑤细胞水平验证:将HT22细胞分为对照组、模型组(β-淀粉样蛋白1-42寡聚体处理36 h建立HT22细胞阿尔茨海默病体外模型)、给药组(先以β-淀粉样蛋白1-42寡聚体预处理24 h,再加入替西帕肽共处理12 h),通过Western blot分析血管紧张素Ⅱ2型受体蛋白表达,ELISA检测突触蛋白1、突触后致密物质95等突触功能标志物表达水平。⑥动物实验验证:实验分为3组,对照组为WT型C57BL/6小鼠,腹腔注射生理盐水;模型组为3xTg小鼠(拟阿尔茨海默症小鼠),腹腔注射生理盐水;给药组为3xTg小鼠,腹腔注射20 nmol/L替西帕肽;均为隔日1次,共给药15次。使用水迷宫技术分析阿尔茨海默病模型小鼠的认知行为学改善;使用Western blot定量分析β-淀粉样蛋白(6E10)、磷酸化的Tau蛋白(P-tau-181)的表达情况。结果与结论:①从DisGeNET数据库筛选出阿尔茨海默病相关联的基因,共得到3397个关联基因;根据蛋白关联度筛选出了10个连接度最高的关键基因:AGTR2、NTSR1、NTSR2、GHSR、C5AR1、C3AR1、OPRM1、SSTR2、OPRD1、STAT3;GO富集分析和KEGG通路分析,提示替西帕肽可能通过改善神经受体-配体功能来改善阿尔茨海默病。②细胞实验提示,替西帕肽可能通过改善阿尔茨海默病的突触功能来发挥治疗作用,血管紧张素Ⅱ2型受体可能是替西帕肽治疗阿尔茨海默病的潜在靶点。③动物实验提示,替西帕肽能够改善3xTg小鼠的认知能力,改善3xTg小鼠模型脑内的异常β-淀粉样蛋白沉积和Tau蛋白磷酸化。④结论:揭示血管紧张素Ⅱ2型受体是替西帕肽作用于阿尔茨海默病病理进程的关键分子靶点,替西帕肽可能通过调控血管紧张素Ⅱ2型受体介导的突触功能改善来治疗阿尔茨海默病。

关键词： Cost analysis   Queueing-inventory model   Simulation   The (s, Q) inventory policy   The GI/M/1 queue   Waiting time distribution  

摘要： This study investigates a single server GI/M/1 queueing system attached with an (s,Q) inventory policy. The system has finite number of waiting rooms for the arrival of demands. Demands arrive in the manner of arbitrary distribution and they are served according to the exponential distribution. Every demand needs a single item from the stock. An order for items is placed when the stock level falls to a predetermined threshold s. An outside source replenishes the stock of the items according to an exponential distribution. The arrival demand waits in the queue for replenishment when stock level is zero. The paper derives the joint probability distribution of the number of demands and the stock level at the pre-arrival epoch. To determine the joint probability distribution at an arbitrary epoch, we obtain a relation between the system length and stock level distribution at the pre-arrival epoch, as well as the residual time of arrival demand as a supplementary variable at the arbitrary epoch. We then determine the probability density function of the waiting time distribution for a demand who joined the queue. We construct the total cost function with the help of performance measures. We numerically determine the optimal values for waiting space, reordering threshold, and order quantity. Numerical results support our analytical findings. The validation of our model is confirmed through simulation experiments. Additionally, a simulation study is conducted for the $GI/G/1$ queueing-inventory model to review the cost analysis for various parameters.

关键词： Ga3+ substitution   Microwave dielectric properties   ZnTa2O6   ZnZrTa2O8  

摘要： Ga³⁺ heterovalent substitution for Zn²⁺ was beneficial for modifying ZnZrTa₂O₈ ceramic. The enlarged Q×f was caused by a combination of grain size and total lattice energy U_Total increase. The improvement of τ_f was attributed to the increase in Ta-O bond energy. Zn_0.99Ga_0.01ZrTa₂O_8.005 ceramics exhibited optimal Q×f of 103,236 ± 2155 GHz (@7.38 GHz) and τ_f = -17.65 ± 1.61 ppm/℃. The improved τ_f provided great convenience for gaining temperature stable dielectric ceramics. Afterward, ZnTa₂O₆ as a temperature compensator was added to adjust the τ_f to zero. The Zn_0.99Ga_0.01ZrTa₂O_8.005 dissolved into ZnTa₂O₆ lattice. As a result, 0.4Zn_0.99Ga_0.01ZrTa₂O_8.005-0.6ZnTa₂O₆ ceramic sintered at 1350 ℃ obtained the desirable dielectric properties: ε_r = 28.18 ± 0.01, Q×f = 81,919 ± 394 GHz (@6.70 GHz), τ_ƒ = -0.51 ± 0.06 ppm/℃.

关键词： Massive MIMO   Precoding   1-Bit DACs   Constructive interference   Nonlinear programming   Bit error rate  

摘要： This paper studies the precoding design for the downlink of massive multiple-input multiple-output (MIMO) systems under phase shift keying (PSK) modulation, where the base station (BS) employs 1-bit digital-to-analog converters (DACs) to reduce system power consumption. We focus on constructive interference (CI)-based precoding under 1-bit constraints. The symbol-scaling CI-based precoding optimization problem is first formulated and then recast as a mixed-integer nonlinear programming (MINLP) problem. We then transform the original problem into a more tractable augmented Lagrangian dual problem by grouping constraints and introducing a quadratic penalty term. We also establish the strong duality between the dual problem and the primal problem. Due to the non-differentiability of the dual function, we propose a projected subgradient ascent (PSGA) algorithm that alternately updates the dual variables and the Lagrange multipliers. Furthermore, an efficient proximal block coordinate descent (PBCD) algorithm is proposed to solve the Lagrangian function minimization subproblem in the PSGA algorithm. Finally, we analyze the computational complexity and provide a detailed convergence proof for the proposed PSGA-PBCD algorithm. Simulation results demonstrate that the proposed PSGA-PBCD algorithm achieves superior bit error rate (BER) performance with a reasonable computational cost.