The effect of respiratory activity,non-invasive respiratory support and facemasks on aerosol generation and its relevance to COVID-19

Respirable aerosols (< 5 µm in diameter) present a high risk of SARS-CoV-2 transmission. Guidelines recommend using aerosol precautions during aerosol-generating procedures, and droplet (> 5 µm) precautions at other times. However, emerging evidence indicates respiratory activities may be a more important source of aerosols than clinical procedures such as tracheal intubation. We aimed to measure the size, total number and volume of all human aerosols exhaled during respiratory activities and therapies. We used a novel chamber with an optical particle counter sampling at 100 l.min^-1 to count and size-fractionate close to all exhaled particles (0.5–25 µm). We compared emissions from ten healthy subjects during six respiratory activities (quiet breathing; talking; shouting; forced expiratory manoeuvres; exercise; and coughing) with three respiratory therapies (high-flow nasal oxygen and single or dual circuit non-invasive positive pressure ventilation). Activities were repeated while wearing facemasks. When compared with quiet breathing, exertional respiratory activities increased particle counts 34.6-fold during talking and 370.8-fold during coughing (p < 0.001). High-flow nasal oxygen 60 at l.min^-1 increased particle counts 2.3-fold (p = 0.031) during quiet breathing. Single and dual circuit non-invasive respiratory therapy at 25/10 cm.H₂O with quiet breathing increased counts by 2.6-fold and 7.8-fold, respectively (both p < 0.001). During exertional activities, respiratory therapies and facemasks reduced emissions compared with activities alone. Respiratory activities (including exertional breathing and coughing) which mimic respiratory patterns during illness generate substantially more aerosols than non-invasive respiratory therapies, which conversely can reduce total emissions. We argue the risk of aerosol exposure is underappreciated and warrants widespread, targeted interventions.     

金银花颗粒在旋风分离器中的流场数值模拟分析

目的 针对金银花颗粒在旋风分离器中的运动行为过程进行研究,考察不同设计参数和操作工艺条件下,颗粒在设备内部的运动过程变化规律。方法 基于仿真模拟技术,考察受不同设备长径比、入口进气雷诺数、颗粒质量流量3个因素影响的金银花颗粒在分离器内的运动规律,并以金银花颗粒得粉率为验证指标参数,对模型可靠性进行了分析。结果 通过仿真模拟得到了各个不同工艺条件下的金银花颗粒运动轨迹分布,计算出了对应设备的颗粒得粉率。提出金银花颗粒分离的最佳工艺建议为设备长径比5∶1,入口进气雷诺数3.23×10⁴,颗粒质量流量80.1 mg/s,得到的金银花颗粒得粉率为96.30%。结论 为旋风分离器内金银花颗粒的有关研究提供指导,同时改善旋风分离器在控制和设计上的不足。     

表面改性与致孔对干姜醇提物压片关键性能改善的研究

目的 以干姜Zingiberis Rhizoma醇提物为研究对象,研究表面改性、聚集与致孔相结合的共处理方式改善干姜醇提物的压片关键性能。方法 以共聚维酮（plasdone S-630,PVP/VA）和碳酸氢铵分别为改性剂和致孔剂,采用喷雾干燥共处理方法制备不同比例的干姜醇提物改性复合粉体,测定并比较各粉体的密度、流动性、粒径、孔隙率和压缩性等粉体学性质和抗张强度、屈服压、功和能等相关压片性质,并采用扫描电子显微镜（SEM）对各粒子表面形态进行表征。结果 仅加入共聚维酮或碳酸氢铵制备的复合粒子的孔隙率、抗张强度（TS）、有效功（Esp）和能（E2）均优于原粉粒子。此外,相比于碳酸氢铵或共聚维酮单独制备的复合粒子,碳酸氢铵-共聚维酮（7.0%、14.0%、21.0%）共喷雾制备的复合粒子所压制片剂的抗张强度进一步提升：分别为（1）3.8～9.7、4.0～12.5、4.2～13.7倍和（2）1.5～2.1、1.3～2.2、1.2～1.8倍。即同时加入共聚维酮和碳酸氢铵制备的多孔复合粒子使上述性质得到进一步改善。另外,崩解时间会随共聚维酮加入而有所延长（9～14 min）,碳酸氢铵的致孔作用...     

Reactivity of human sera in a sensitive, high-throughput pseudovirus-based papillomavirus neutralization assay for HPV16 and HPV18

Sensitive high-throughput neutralization assays, based upon pseudoviruses carrying a secreted alkaline phosphatase (SEAP) reporter gene, were developed and validated for human papillomavirus (HPV)16, HPV18, and bovine papillomavirus 1 (BPV1). SEAP pseudoviruses were produced by transient transfection of codon-modified papillomavirus structural genes into an SV40 T antigen expressing line derived from 293 cells, yielding sufficient pseudovirus from one flask for thousands of titrations. In a 96-well plate format, in this initial characterization, the assay was reproducible and appears to be as sensitive as, but more specific than, a standard papillomavirus-like particle (VLP)-based enzyme-linked immunosorbent assay (ELISA). The neutralization assay detected type-specific HPV16 or HPV18 neutralizing antibodies (titers of 160-10240) in sera of the majority of a group of women infected with the corresponding HPV type, but not in virgin women. Sera from HPV16 VLP vaccinees had high anti-HPV16 neutralizing titers (mean: 45000; range: 5120-163840), but no anti-HPV18 neutralizing activity. The SEAP pseudovirus-based neutralization assay should be a practical method for quantifying potentially protective antibody responses in HPV natural history and prophylactic vaccine studies.     

HPV6b L1蛋白在昆虫细胞中的表达及其作为特异性诊断抗原的初步研究

目的：研究人乳头瘤病毒6b结构蛋白（HPV6b L1)在昆虫细胞系统的表达及其作为特异性诊断抗原的可行性,为HPV感染的血清学诊断及基因工程疫苗研究作准备。方法：采用HPV6b L1重组杆状病毒感染sf-9昆虫细胞制备HPV6b L1,经氯化梯度离心纯化,Western blot分析及电镜观察鉴定;用1μg、5μg和20μg三种剂量免疫小鼠,以检测小鼠血清抗体反应;并用HPV6b L1作为诊断抗原检测HPV感染者（尖锐湿疣及宫颈癌）和健康对照者共112例血清特异性抗体。结果：HPV6b L1在昆虫细胞中得到表达,并可自行组装形成VLPs,且予1μg剂量免疫小鼠就能产生阳性血清抗体反应,HPV6b L1 VLPs特异性抗体对HPV6感染的敏感性和特异性分别为78．6％和97．1％。结论：HPV6b L1 VLPs具较强的免疫原性和抗原性,血清中检测到的HPV6b L1抗体对HPV6感染具较高的特异性,可进一步用于HPV感染的血清学诊断及防治尖锐湿疣的基因工程疫苗研究。     

微乳液反应法制备磺胺嘧啶银均匀微晶及其质量评价

目的：应用微乳液反应法制备磺胺嘧啶银均匀微晶,并评价其质量。方法：利用磺胺嘧啶钠微乳和硝酸银微乳混合后反应的方法,制备磺胺嘧啶银均匀微晶,用透射电镜观察其形态和大小,以Ｘ－射线衍射分析、红外光谱、核磁共振、差热分析等手段检测磺胺嘧啶银均匀微晶各种理化特性。结果：磺胺嘧啶银均匀微晶的粒径大小约为２～４μｍ,均匀微晶的结晶性好,纯度高。体外抑菌实验表明该品比市售磺胺嘧啶银具有更好的抑菌效果。结论：用微乳液反应法能获得磺胺嘧啶银均匀微晶。     

骨水泥和非骨水泥固定假体周围骨溶解X线征象差异与磨损颗粒关系的初步分析

探讨不同固定方式假体周围骨溶解X线征象差异与磨损颗粒迁移特点及其易聚积部位之间的联系 ,分析磨损颗粒在假体无菌性松动中的作用。方法 :观察因无菌性松动行翻修术的 39个国产人工髋关节术前X线片 ,按部位及固定方式分组统计假体周围不同区域衬性和膨胀性骨溶解的发生率 ,并测算溶骨带宽或溶骨面积。结果 :非骨水泥固定髋臼假体周围各区 (Delee分区法 )衬性骨溶解发生率明显高于骨水泥固定组 (P <0 0 5 ) ,溶骨带宽以三区最重 (P <0 0 5 )并大于骨水泥固定组对应区 (P <0 0 5 ) ;膨胀性骨溶解以三区发生率最高 (P <0 0 5 ) ,但两种固定方式各对应区之间发生率及溶骨面积均无显著性差异 (P >0 0 5 )。柄周衬性骨溶解宽度人工股骨头组除一、四区 (Gruen分区法 )、全髋关节组除三、四区无显著性差异 (P >0 .0 5 )外 ,其它各对应区均以骨水泥固定组较重 (P <0 .0 5 ) ;膨胀性骨溶解发生率以一、七区最高 (P <0 .0 5 ) ,两种固定方式各对应区之间溶骨面积差异无显著性意义 (P >0 .0 5 )。结论 :无菌性松动假体周围骨溶解的发生部位及严重程度与磨损颗粒迁移和聚集的部位有关 ,固定方式不同骨溶解的X线表现亦有差异。阻断磨损颗粒的扩散可能是防止骨溶解发生的有效方法之一。     

Influence of Fluorescent Labelling of Polystyrene Particles on Phagocytic Uptake,Surface Hydrophobicity,and Plasma Protein Adsorption

Purpose. To investigate the influence of fluorescent labelling of polystyrene particles on phagocytic uptake, surface hydrophobicity and protein adsorption. Methods. Phagocytic uptake was analysed using chemiluminescence. Hydrophobicity was quantified by adsorption measurements of a hydrophobic dye. Protein adsorption was evaluated by two-dimensional electrophoresis. Results. Commercially available fluorescently labelled particles showed marked differences when compared to unlabelled particles: phagocytic uptake and surface hydrophobicity of labelled particles were diminished. Also the plasma protein adsorption pattern was found to be different from the unlabelled particles: for example, the amount of fibrinogen adsorbed was strongly reduced on the labelled particles. On the other hand, some unknown proteins could be detected on the fluorescently marked particles. In contrast, plain polystyrene particles and labelled ones could be successfully synthesised by Paulke which did not show any considerable differences in phagocytic uptake, surface hydrophobicity and protein adsorption. Polysorbate 20 added as stabilizer to particle suspensions led to completely different behaviour of the particles: the particles showed altered protein adsorption patterns, dominated by immunoglobulins and especially by apolipoproteins. Furthermore, these particles were not phagocytized at all. Conclusions. Surface hydrophobicity and phagocytic uptake in vitro as well as the interactions with plasma proteins of commercially available polystyrene particles were strongly affected by fluorescent labelling. Particles synthesised by Paulke remained unchanged after labelling. The results show the importance of thorough surface characterization for using particles in test systems in vitro and in vivo.     

氧化铝颗粒大小对PEO—NaSCN络合物电导率的影响

研究分散第二相Ａｌ２Ｏ３的含量及颗粒大小对ＰＥＯ－ＮａＳＣＮ络合物电导的影响,结果表明：当颗粒度为０．７μｍ时,电导率比纯ＰＥＯ－ＮａＳＣＮ提高了一个半数量级。颗粒度较大时,电导率均比纯ＰＥＯ－ＮａＳＣＮ低,并在ｗＡｌ２Ｏ３＝０．２５时,存在电导率最大的峰值。     

汽油车尾气颗粒物对小鼠免疫功能的影响

运用大流量空气采样器采集汽油车尾气颗粒物,用其有机提取物注射小鼠,测定小鼠外周血白细胞分类、小鼠体重增长及脏器重量、抗体形成细胞试验及腹腔巨噬细胞吞噬功能试验４ 个指标。结果表明：小鼠腹腔染毒尾气颗粒物有机提取物（１０ｍｇ／ｋｇ 、４０ｍｇ／ｋｇ 、１６０ｍｇ／ｋｇ） 均可引起外周血白细胞中淋巴细胞比例降低、小鼠体重增长缓慢、脾脏与胸腺萎缩、抗体生成细胞分泌抗体减少、巨噬细胞吞噬功能受到抑制,并且均具有剂量反应关系。表明尾气颗粒物有机提取物对小鼠的免疫功能损伤是多方面的、广泛的。