长沙市不同污染程度区域桂花和香樟叶表面PM2.5吸附量及其影响因素

为阐释不同污染程度下城市绿化植物吸滞PM_2.5机理、解析污染物来源,应用气溶胶再发生器定量测定长沙市常见的2种园林绿化树种(桂花和香樟)植物叶片PM_2.5吸附量,同时应用原子力显微镜(AFM)观察了不同污染区(交通区、文教区、清洁区)植被的叶表面微形态特征,使用离子色谱仪测定样品中水溶性离子含量.结果表明: 污染程度与植物叶表面PM_2.5吸附量呈正相关,不同植物单位叶面积PM_2.5吸附量全年均值表现为交通区(0.56±0.04 μg·cm^-2)＞文教区(0.48±0.06 μg·cm^-2)＞清洁区(0.33±0.02 μg·cm^-2),植物单位叶面积PM_2.5吸附量季节变化为冬季(0.70±0.10 μg·cm^-2)＞春季(0.43±0.14 μg·cm^-2)＞秋季(0.39±0.12 μg·cm^-2)＞夏季(0.31±0.09 μg·cm^-2),桂花的单位叶面积PM_2.5吸附量大于香樟;污染程度轻的区域的植物叶片比较光滑,污染程度重的区域的叶片较粗糙,植物粗糙度排序为交通区(195.45±16.09 nm)＞文教区(176.99±8.45 nm)＞清洁区(131.88±12.98 nm);不同污染程度地区PM_2.5离子含量均表现为冬季最大,其次是春季和秋季,夏季最低;3个污染区PM_2.5离子成分均以Na⁺、NH₄⁺、Cl^-和Br^-这4种离子为主,不同程度污染区PM_2.5污染均以移动源污染为主.     

Nuclear structure in early mouse embryos: A comparative ultrastructural and immunocytochemical study with special emphasis on the "2-cell block in vitro"

The embryos from many outbred and inbred strains of mice are arrested at the late 2-cell stage when cultured in vitro in simple culture media. This phenomenon is referred to as the "2-cell block in vitro". The ultrastructural morphology of the nuclei of the blocked embryos is not yet well described. In the present paper we documented the results of a comparative study on the nuclei of mouse embryos, both normally developing and arrested at the 2-cell stage. The blocked embryos maintain the morphological integrity of their nuclei. Main nuclear domains (nucleolus precursor bodies, interchromatin granule clusters, perichromatin granules, and perichromatin fibrils), typical for the control embryos, are observed in the blocked ones. A number and morphological characteristics of these nuclear substructures are not changed significantly in the blocked embryos. At the same time, RNA polymerase II and pre-mRNA splicing factors are redistributed in the nucleus of the blocked embryos. Although something goes to show that nuclear organization of the blocked embryos differ from that of the control, we could not reveal in the blocked embryos distinct signs of degeneration which might characterize aged or dying cells. Our data confirm a peculiar functional state of the 2-cell blocked embryos.     

不同容量胸段经椎间孔硬膜外注射阻滞范围的CT影像研究及诊断性阻滞的可行性分析

摘要 目的：探讨不同容量对胸段经椎间孔硬膜外注射（TFEI）药液扩散范围和镇痛效果的影响以及胸段TFEI用于诊断性阻滞的可行性。方法：选择2021年1月至2022年12月南京大学医学院附属鼓楼医院收治的胸段带状疱疹相关疼痛患者140例,随机分为4组,实施单次TFEI并分别注入不同容量含造影剂局麻药（A组：0.2 mL;B组：0.5 mL;C组：1.0 mL;D组：2 mL）,CT扫描并观察造影剂在硬膜外向头侧、尾侧及总扩散节段,造影剂在椎间孔、同侧椎旁间隙、同侧及对侧硬膜外间隙扩散情况,判断是否为选择性神经根阻滞。评估注射前、注射后30分钟及24小时视觉模拟评分（VAS）。结果：头侧和尾侧扩散节段以及总扩散节段数,D组最多,A组最少（P<0.05）;C组、D组造影剂扩散≥3个节段发生率明显高于B组（P<0.05）;C组、D组病例造影剂扩散至同侧椎旁间隙和对侧硬膜外间隙的发生率明显高于A组、B组（P<0.05）,仅A组37.1%的病例实现选择性神经根阻滞,其余各组均无选择性阻滞病例。注射后30分钟,C、D组VAS评分显著低于A、B组（P<0.05）;注射后24小时,D组VAS评分显著低于A、B组（P<0.05）。结论：胸段带状疱疹相关疼痛患者TFEI药液扩散范围随注射容量的增加而扩大,且在硬膜外倾向于头侧扩散,2 mL容量单次TFEI可阻滞3个以上的神经节段,获得良好的镇痛效果。胸段TFEI行诊断性阻滞的可行性较差。     

Mg2+-dependent gating and strong inward rectification of the cation channel TRPV6

TRPV6 (CaT1/ECaC2), a highly Ca(2+)-selective member of the TRP superfamily of cation channels, becomes permeable to monovalent cations in the absence of extracellular divalent cations. The monovalent currents display characteristic voltage-dependent gating and almost absolute inward rectification. Here, we show that these two features are dependent on the voltage-dependent block/unblock of the channel by intracellular Mg(2+). Mg(2+) blocks the channel by binding to a site within the transmembrane electrical field where it interacts with permeant cations. The block is relieved at positive potentials, indicating that under these conditions Mg(2+) is able to permeate the selectivity filter of the channel. Although sizeable outward monovalent currents were recorded in the absence of intracellular Mg(2+), outward conductance is still approximately 10 times lower than inward conductance under symmetric, divalent-free ionic conditions. This Mg(2+)-independent rectification was preserved in inside-out patches and not altered by high intracellular concentrations of spermine, indicating that TRPV6 displays intrinsic rectification. Neutralization of a single aspartate residue within the putative pore loop abolished the Mg(2+) sensitivity of the channel, yielding voltage-independent, moderately inwardly rectifying monovalent currents in the presence of intracellular Mg(2+). The effects of intracellular Mg(2+) on TRPV6 are partially reminiscent of the gating mechanism of inwardly rectifying K(+) channels and may represent a novel regulatory mechanism for TRPV6 function in vivo.     

Differential response of DPI-modified cardiac Na+ channels to antiarrhythmic drugs: No flicker blockade by lidocaine

Summary Elementary Na⁺ currents were recorded in cell attached patches from short-time cultured neonatal cardiocytes in order to test the hypothesis whether the open state of DPI-modified, noninactivating cardiac Na⁺ channels is basically sensitive to blocking drug molecules such as antiarrhythmics.Lidocaine (300 mol/liter) effectively reduced the open probability of cardiac Na⁺ channels and, at a stimulation rate of 1 Hz, depressed the reconstructed macroscopic peak I _Na to 40+ 3.5% of the predrug value. The same drug concentration failed to influence DPI-modified Na⁺ channels. Their open state proved almost insensitive to lidocaine. _open decreased only slightly to 85 ±2%. Still more importantly, the number of transitions between the conducting and a nonconducting configuration did not increase. At –40 mV, lidocaine may interfere with the open state with an association rate constant of 1.3×10⁵ mol^–1sec^–1 which is about two orders of magnitude smaller than the rate constant obtained with propafenone or prajmalium. Moreover, propafenone (10–20 mol/liter) or prajmalium (30 mol/liter) led to a tremendous increase in the number of transitions between the open and a nonconducting configuration. Lidocaine also failed to evoke a fast flicker blockade with reaction kinetics in the microsecond range.It is concluded that DPI-modified cardiac Na⁺ channels discriminate between lidocaine and other antiarrhythmic drugs. As a tentative explanation, this might be indicative for multiple binding sites for those drugs in cardiac Na⁺ channels.This work was supported by a grant from the Deutsche Forschungs-gemeinschagt (Ko 778/2–3), Bonn.     

近50年京津冀气候舒适度的区域时空特征分析

受气候变化影响,区域气候舒适期势必会发生不同程度的变化。从气候舒适性的视角出发,利用京津冀地区1966—2015年的170个观测站点50年逐日气象资料,以温湿指数、风效指数、着衣指数及其综合指数为气候舒适性的评价指标,统计分析区域气候舒适期的起止日期、天数及其年际间变化规律,揭示京津冀区域气候舒适度的时空变化特征,为区域人口合理分布和气候资源评价提供科学依据。此外,以日为时间尺度进行气候舒适期分析,有利于气候变化背景下区域间横向和区域内纵向的比较研究。结果显示:(1)京津冀气候舒适度指数近50年来的变化趋势基本相同,综合指数呈显著增加趋势;但各地间变幅存在一定差异,其中天津气候舒适度指数变化幅度最为明显,北京变化相对平稳。(2)从气候舒适度综合指数来看,京津冀地区气候舒适期年内分布呈"M"型,舒适期相对集中在4—5月、9—10月,舒适和较舒适等级的月累计日数均达到28 d以上,其中5月气候最为舒适,舒适等级日数最多,达到24—26 d;北京年平均舒适天数最多(100 d),天津最少(91 d)。(3)从单一气候舒适度指数来看,京津冀舒适和较舒适等级的初始日期大多呈显著的提前趋势;终止日期和天数大多略有增加,但变化趋势不显著。而综合指数显示,1966—2015年较舒适等级的初始日期变化最为显著,大约每10年提前3—4 d;天津和河北终止日期变化也达到显著水平,大约每10年推迟1—2 d,北京增加趋势不明显。(4)京津冀气候舒适期的空间分布显示,舒适等级的日数从西北向东南地区呈减少特征,河北北部舒适等级的年平均日数最多达115—120 d,东南部最少,不足90 d。     

1996—2008年广东省城市化进程与生态环境的协调性分析

在构建城市化和城市生态环境评价指标体系、并对广东省城市化发展水平与城市生态环境质量分别进行综合评价的基础上,将模糊数学中的隶属度引入到城市化与市生态环境协调度的计算中,并对两者协调发展程度的变化趋势进行了分析。结果发现,1996-2008年间,广东省城市综合发展与城市环境的协调度具有明显的阶段性和波动性特征,总体均呈现下降趋势;静态协调度可大体上划分为两个阶段,其中前9年均处于总体协调阶段,以1998年的静态协调度为最高,但自2005年后,两者的静态协调度逐年降低,处于不协调阶段;与静态协调发展度相比较,广东省的城市化发展与城市生态环境的动态协调度变化略为平滑。说明广东省生态环境对城市化的响应较为明显,但生态环境质量发展指数的上升滞后于城市化发展的进程。随着城市化进程的不断发展,城市化与生态环境的矛盾逐渐加剧,生态环境对城市化的约束作用逐渐增加,系统的协调性也有所下降。     

凝集素抑制林蛙卵裂沟新膜外露的作用

剥去受精膜的林蛙卵分裂时,分裂沟中的新膜会暴露出来。林蛙老膜上有大量均匀分布的麦胚和大豆凝集素受体。卵裂前,将剥去受精膜的蛙卵浸于上述的凝集素溶液中,新膜的外露就被抑制。凝集素愈浓,浸泡时间愈长,抑制愈大。在这些卵的表面可看到一层较厚的由凝集素引起的外被。碱处理过的受精卵表面,凝集素受体减少,凝集素抑制新膜外露的作用亦减弱,由凝集素引起的外被亦薄。凝集素是多价的,会在细胞表面产生交链,形成“外骨骼”,抑制新膜外露。凝集素也可通过受体,影响微丝,产生作用。     

双侧股神经阻滞用于双膝关节置换术患者的麻醉效果和对血清炎性因子水平的影响

目的:研究双侧股神经阻滞术用于双膝关节置换术患者麻醉效果和对患者血清炎性因子水平的影响。方法:选择2015年10月～2018年10月在我院进行双膝关节置换术的110例患者,按照其入院顺序经随机数字表法分为两组,每组55例。对照组采用全身麻醉,研究组采用双侧股神经阻滞联合全身麻醉。比较两组的麻醉情况,治疗前后血清炎性因子白介素6(IL-6)、C反应蛋白(CRP)、舒张压(DBP)、收缩压(SBP)、心率(HR)水平的变化。结果:两组麻醉时间比较差异无统计学意义(P0.05);研究组拔管、恢复室停留和苏醒时间均显著短于对照组(P0.05)。两组术后24 h、48 h血清炎性因子IL-6、CRP水平均高于术前,但研究组以上指标均显著低于对照组(P0.05);两组术中DBP、SBP、HR水平均较术前显著降低(P0.05),但研究组DBP、SBP、HR水平均显著高于对照组(P0.05),两组术后DBP、SBP、HR水平比较差异均无统计学意义(P0.05)。结论:与单纯采用全身麻醉相比,双侧股神经阻滞可有效改善双膝关节置换术患者的麻醉效果,并降低其血清炎症因子和稳定其血流动力学。     

混合应用罗哌卡因、氯胺酮在新生儿骶管阻滞中的作用

目的:探明罗哌卡因、氯胺酮混合液在新生儿骶管阻滞术后镇痛的疗效和不良反应.方法:选取45例即将行骶管阻滞的新生儿,随机分成A、B、C三组,每组15人,其中A组患者行罗哌卡因骶管阻滞,B组患者行罗哌卡因骶管阻滞并氯胺酮皮下注射,C组患者行罗哌卡因、氯胺酮混合液骶管阻滞.术后于1、2、4、6、8、12、24h分别记录各患者的镇痛情况以及镇痛时间,采用FLACC法评价镇痛效果,以评分＜4分的维持时间作为有效镇痛时间.并且观察术后48h内不良反应的发生情况.结果:A组与B组之间比较镇痛时间以及术后不同时间点不需要镇痛的患者例数,发现两组间并没有较大差别(P＞0.05).相比较于A、B两组,C组患者阵痛时间明显延长,并且术后4、6、8、12、24h患者不需要镇痛明显增多(P＜0.05).而在不良反应方面,三组患者均未表现出过强的不良反应.结论:罗哌卡因、氯胺酮混合液用于新生儿骶管阻滞效果较佳,且不良反应少.