Measuring the Effect of Pack Shape on Gravel’s Pore Characteristics and Permeability Using X-ray Diffraction Computed Tomography

Particle shape is one of the critical parameter factors that affect gravel’s pore structure and permeability. However, few studies have considered its effects on engineering applications due to the difficulty of conducting laboratory tests. To overcome these difficulties, new methods of estimating the gravel pack shape that involve manual work and measuring the surface area of particles and pores based on support vector machine segmentation and the reconstruction of X-ray diffraction computed tomography (CT) images were proposed. Under the same conditions, CT tests were carried out on gravel packs and two other regular-shaped particle packs to investigate the influence of particle shape on the fractal dimension of gravel’s pore–particle interface and the specific surface area of the pore network. Additionally, permeability tests were performed to study the effect of particle shape on gravel’s hydraulic conductivity. The results showed that a gravel pack with a larger aspect ratio and a smaller roundness had a larger specific pore network surface area and a more complex pore structure, leading to lower permeability. This kind of gravel had a more significant length, quantity, and tortuosity of the seepage path when seepage occurred in a two-dimensional seepage field simulation. Therefore, we suggest that the filter materials of hydraulic projects should preferably use blasting gravel with a larger aspect ratio and smaller roundness to achieve better anti-seepage properties. In addition, projects can increase pores’ specific surface area using our method as a control factor in filter construction.     

金黄色葡萄球菌血流感染住院患儿临床特征及危险因素

目的 了解儿童金黄色葡萄球菌(SA)血流感染的临床特点以及菌株的药敏特征,探讨耐甲氧西林金黄色葡萄球菌(MRSA)血流感染和SA血流医院感染(HA)的易感因素。方法 回顾性分析2014年1月—2019年12月某儿童医院血培养检出SA住院患儿的病历资料,根据其药敏试验结果及来源分为MRSA组与甲氧西林敏感金黄色葡萄球菌(MSSA)组、HA组与社区感染(CA)组,应用卡方检验和logistic回归分析MRSA血流感染及HA血流感染的危险因素。结果 共纳入143例病例,男女比例为1.8∶1,<1岁71例(49.6%),病灶性血流感染90例(62.9%)。MARS组50例(35.0%),MSSA组93例(65.0%);HA组73例(51.0%),CA组70例(49.0%)。机械通气[OR=17.320,95%CI(1.576～190.399)]、抗菌药物联合使用[OR=0.580,95%CI(0.359～0.938)]是MRSA血流感染的独立危险因素(均P<0.05)。机械通气[OR=31.466,95%CI(1.434～690.538)]、入院前使用抗菌药物[OR=24.524,...     

鲍曼不动杆菌医院感染分布特征及耐药性分析

目的研究鲍曼不动杆菌的医院感染分布特征及其对常见抗生素的耐药性。方法采用回顾性方法统计分析206株鲍曼不动杆菌的标本来源、感染科室分布及耐药状况。结果 206株鲍曼不动杆菌中,来自痰液154株（74.76%）,来源于咽拭子18株（8.74%）及伤口分泌物15株（7.28%）;感染科室分别为呼吸内科64株（31.07%）,重症监护病房（ICU）35株（16.99%）,血液内科30株（14.56%）。药物敏感试验结果显示,鲍曼不动杆菌对β-内酰胺类、氨基苷类、喹诺酮类均有较高的耐药性,而对碳青酶烯类、β-内酰胺类及含酶抑制剂复合药物较敏感,其中最敏感的是亚胺培南（91.8%）,其次是美罗培南（84.5%）。结论鲍曼不动杆菌临床分离株多来自于痰液标本和呼吸科病房,对多种抗菌药物的耐药率较高,临床应加强对鲍曼不动杆菌耐药性的监控并防治耐药菌株的传播流行。     

X-ray Fluorescence Analysis of Pigments in Gothic Frescoes,Coats of Arms,and Polychromy on Sculptures on the Triforium in St. Vitus Cathedral on the Territory of the Czech Kingdom in the 14th Century

Pigments in the paints used for the coats of arms, polychromy on sculptures, and pigments in frescoes characterize not only the epoch but also individual creators or groups of artists involved in their creation. X-ray fluorescence analysis is a non-destructive method suitable for determining the chemical composition of these artifacts. This article covers the results of measurements of selected objects, and compares them with similar objects from the territory of the Czech Kingdom in the 14th century.     

罂粟霜霉病病原及其生物学特性

目的 :为罂粟霜霉病的深入研究和防治提供理论依据。方法 :在罂粟生长季节系统观察和描述症状发展变化过程。用悬滴法测定温度、营养和 pH值对孢子囊萌发的影响 ,用硫酸法控制小容器相对湿度和载玻片法测定湿度对孢子囊萌发的影响。结果和结论 :罂粟霜霉病有系统型和非系统型 (即叶斑型 )两种症状类型。病原菌Peronospora arborescens孢子囊椭圆形至球形 ,无色至淡灰色 ,壁薄。卵孢子淡黄色 ,壁较光滑。不同种植区的孢子囊大小有差异。孢子囊萌发的适宜温度为 12～21℃ ,最适温度 16℃。孢子囊在相对湿度 100%时萌发率为 5.5% ,低于 95%不能萌发 ,而在水滴中的萌发率高达 41%。1∶5的罂粟叶片榨出液对孢子囊的萌发有较强的刺激作用 ,不同浓度的蔗糖液和土壤浸渍液无明显刺激作用。孢子囊萌发的适宜 pH为 6.47～8.0 4,最适 pH7.38。     

温度对山茱萸开花与结果习性的影响

目的研究温度对山茱萸开花与结果习性的影响。方法对所选定的不同海拔高度的12株20~50年树龄的山茱萸为研究对象,进行定株、定时观察与记载。结果当日均温持续稳定在8℃以上约3~5d,花蕾将开始绽放;当日均温稳定在12℃以上3~5d,小花将开始开放;当日均温稳定在23℃以下时,果实纵、横径生长均较快。结论对制订山茱萸标准操作规程(简称SOP)及指导合理生产具有实际意义。     

黑顺片炮制过程中6种酯型生物碱的变化规律研究

研究黑顺片炮制过程中6种酯型生物碱的变化规律及特征图谱,为黑顺片的炮制原理研究奠定基础.采用Phenomenex Gemini C18柱(4.6 mm×250 mm,5μm),流动相乙腈-40 mmol·L-1醋酸铵(浓氨调pH 10.0)梯度洗脱,流速0.8 mL·min-,检测波长235 nm,进样量10 ～ 20 μL,测定6种酯型生物碱含量的变化以及建立炮制过程的特征图谱.随着炮制过程的进行,双酯型生物碱含量降低,单酯型生物碱变化规律不明显,各炮制过程环节的7种附子“状态”特征图谱差异明显.特征图谱中共标记13个峰,除6种已知单双酯型生物碱外,其余7个峰峰面积变化趋势与双酯型生物碱的变化趋势一致.该方法准确可靠,重复性好,可为揭示黑顺片炮制过程中指标成分的变化规律以及阐明炮制原理提供参考.     

博落回中生物碱质谱裂解规律研究进展

博落回中生物碱的代谢途径可简化为：氨基酸→苄基异喹啉类生物碱→四氢原小檗碱型生物碱（或者转化成阿朴芬类生物碱）→N-甲基-四氢原小檗碱型生物碱（或者转化成原小檗碱型生物碱）→普罗托品类生物碱→二氢苯并菲啶类生物碱→苯并菲啶类生物碱→苯并菲啶类生物碱二聚体。对博落回代谢途径中9类生物碱质谱裂解规律的总结,为利用质谱裂解方式初步确定生物碱的结构类型;利用LC-MS鉴定不同产地、不同时期、不同部位博落回中标识性生物碱;以博落回中生物碱为原料而开发的中兽药药动学以及药物残留的研究;解析博落回中微量生物碱的结构式以及对其他天然药物中同类生物碱的质谱研究提供参考。     

白芍药材UPLC特征指纹图谱研究

目的:建立白芍药材的UPLC特征指纹图谱分析方法,为快速评价白芍药材的质量,完善白芍的质量控制方法提供依据.方法:采用ACQUITY UPLC HSS T3色谱柱(2.1 mm × 100 mm,1.8 μm),流动相乙腈-0.05%磷酸水溶液,检测波长230 nm.结果:建立了白芍药材的UPLC特征指纹图谱共有模式,标定了15个共有峰,指认了其中5个共有峰,15批白芍药材的相似度为0.891～0.9960结论:该方法快速,可用于评价白芍药材质量.