电镜技术在四类医学媒介生物分类鉴定中的应用研究

目的 利用扫描电镜技术对形态相似的医学媒介生物种类进行观察、描述、比较分析,为此类媒介生物的鉴定提供新的方法.方法 选择媒介4类17种,常规标本制作并在电镜下观察其超微结构,并进行描述比较和分析.结果 共观察到4类媒介6类触角感受器,具有不同程度的种间差异.结论 对医学媒介生物触角感受器的研究,为更好地把握各类感受器的功能,揭示触角的感受机理和防治医学媒介提供新的途径.     

数字切片扫描仪产品主要性能指标的检验方法初探

数字切片扫描仪产品按照医疗器械进行管理,管理类别为Ⅱ类。本文依据日常检验工作要求,归纳总结出一套现实可行的,针对数字切片扫描仪产品主要性能指标的检验方法,以期规范和指导该类产品的检验。     

Time Interval of Two Injections and First-Dose Dependent of Accelerated Blood Clearance Phenomenon Induced by PEGylated Liposomal Gambogenic Acid: The Contribution of PEG-Specific IgM

Repeated injection of PEGylated liposomes can cause the disappearance of long circulating property because of the induction of anti-PEG IgM antibody referred to as “accelerated blood clearance (ABC) phenomenon.” Although ABC phenomenon typically occurs when entrapped drugs are chemotherapeutic agent with low cytotoxic, there is little evidence of accelerated blood clearance of PEGylated herbal-derived compound on repeated injection. Herein, we investigated the blood concentration of PEGylated liposomal gambogenic acid (PEG-GEA-L), a model PEGylated liposomal herbal extract, on its repeated injection to rats. We found time interval between injections had considerable impact on the magnitude of ABC phenomenon induced by PEG-GEA-L. When time interval was prolonged from 3 days to 7 days, ABC phenomenon could be attenuated. Furthermore, its magnitude was enhanced accompanied by a marked rise in the accumulation of PEG-GEA-L in the liver and spleen in a first-dose–dependent manner. Consistently, the level of anti-PEG IgM significantly increased with the first dose of PEG-GEA-L and decreased with the extended time interval between injections, which implies anti-PEG IgM is a major contributor to the ABC phenomenon. Notably, the increased expression of liver anti-PEG IgM was accompanied by an increased expression of efflux transporters in the induction process of the ABC phenomenon.     

Systematic determination of absolute absorption cross-section of individual carbon nanotubes

Optical absorption is the most fundamental optical property characterizing light–matter interactions in materials and can be most readily compared with theoretical predictions. However, determination of optical absorption cross-section of individual nanostructures is experimentally challenging due to the small extinction signal using conventional transmission measurements. Recently, dramatic increase of optical contrast from individual carbon nanotubes has been successfully achieved with a polarization-based homodyne microscope, where the scattered light wave from the nanostructure interferes with the optimized reference signal (the reflected/transmitted light). Here we demonstrate high-sensitivity absorption spectroscopy for individual single-walled carbon nanotubes by combining the polarization-based homodyne technique with broadband supercontinuum excitation in transmission configuration. To our knowledge, this is the first time that high-throughput and quantitative determination of nanotube absorption cross-section over broad spectral range at the single-tube level was performed for more than 50 individual chirality-defined single-walled nanotubes. Our data reveal chirality-dependent behaviors of exciton resonances in carbon nanotubes, where the exciton oscillator strength exhibits a universal scaling law with the nanotube diameter and the transition order. The exciton linewidth (characterizing the exciton lifetime) varies strongly in different nanotubes, and on average it increases linearly with the transition energy. In addition, we establish an empirical formula by extrapolating our data to predict the absorption cross-section spectrum for any given nanotube. The quantitative information of absorption cross-section in a broad spectral range and all nanotube species not only provides new insight into the unique photophysics in one-dimensional carbon nanotubes, but also enables absolute determination of optical quantum efficiencies in important photoluminescence and photovoltaic processes.Single-walled carbon nanotubes (SWNTs), a model one-dimensional nanomaterial system, constitute a rich family of structures (1). Each single-walled nanotube structure, uniquely defined by the chiral index (n,m), exhibits distinct electrical and optical properties (2–5). Quantitative information of SWNT absorption cross-section is highly desirable for understanding nanotube electronic structures, for evaluating quantum efficiency of nanotube photoluminescence (5, 6) and photocurrent (7–9), and for investigating the unique many-body effects in 1D systems (10–16). Despite its obvious importance, reliable experimental determination of nanotube absorption cross-section at the single-tube level is still challenging (17). Previous absorption measurements on ensemble nanotube samples only provide averaged behavior (18–20). Recent absorption studies of individual nanotubes, suffering from small absorption signals and/or slow laser-frequency scanning, cannot determine the absolute absorption cross-section and are limited in achievable spectral range (15, 21–23).We demonstrate here a high-sensitivity polarization-based homodyne method to measure nanotube absorption spectra. By manipulating the light polarization, we enhanced the nanotube-induced transmission contrast, ΔI/I, by two orders of magnitude, and this enhanced transmission contrast can be quantitatively related to nanotube absorption cross-section along and perpendicular to the nanotube axis. Using this polarization control together with supercontinuum laser source, we realized high-throughput and broadband absorption measurements at the single-tube level; combined with electron diffraction technique on the same tube, it enables absolute determination of absorption cross-sections of individual chirality-defined nanotubes, to our knowledge for the first time. We obtained quantitative absorption spectra of over 50 SWNTs of different chiralities, and established a phenomenological formula for absorption cross-sections of different nanotubes. The chirality-dependent nanotube absorption spectra reveal unique 1D photophysics in nanotubes, including a universal scaling behavior of exciton oscillator strength and of exciton resonance linewidth.     

Effect of Ornamental Stone Waste Incorporation on the Rheology,Hydration, Microstructure,and CO2 Emissions of Ordinary Portland Cement

The ornamental stone industry generates large amounts of waste thus creating environmental and human health hazards. Thus, pastes with 0–30 wt.% ornamental stone waste (OSW) incorporated into ordinary Portland cement (OPC) were produced and their rheological properties, hydration kinetics, and mechanical properties were evaluated. The CO₂ equivalent emissions related to the pastes production were estimated for each composition. The results showed that the paste with 10 wt.% of OSW exhibited similar yield stress compared to the plain OPC paste, while pastes with 20 and 30 wt.% displayed reduced yield stresses up to 15%. OSW slightly enhanced the hydration kinetics compared to plain OPC, increasing the main heat flow peak and 90-h cumulative heat values. The incorporation of OSW reduced the 1-, 3-, and 28-days compressive strength of the pastes. Water absorption results agreed with the 28 days compressive strength results, indicating that OSW increased the volume of permeable voids. Finally, OSW incorporation progressively reduced the CO₂ emission per m³ of OPC paste, reaching a 31% reduction for the highest 30 wt.% OSW content. Overall, incorporating up to 10 wt.% with OSW led to pastes with comparable fresh and hardened properties as comported to plain OPC paste.     

Influence of Basalt Fibers on the Crack Resistance of Asphalt Mixtures and Mechanism Analysis

The paper aims to investigate the influence of basalt fiber (BF) on the crack resistance of the asphalt mixture and conduct a mechanical analysis. First, two typical asphalt mixtures, namely AC-13 and SMA-13, were designed. The impact of BF on the mixture design results was analyzed. Then, several macroscopic tests, namely the four-point bending test, indirect tensile test, and semicircular bending test (SCB), were conducted to assess the effect of BF on the cracking resistance of asphalt mixtures. Finally, the influence of BF on the cracking resistance of asphalt mixtures was analyzed based on an environmental scanning electron microscope (ESEM) observation. The results show that: (1) BF increases the optimal asphalt content of AC13 and decreases the optimal asphalt content of SMA-13, which is caused by the different asphalt-absorption capacity of BF and lignin fiber (LF). (2) BF enhances both the fatigue crack resistance and temperature crack resistance of asphalt mixtures. The enhancement on the SMA-13 is more significant, indicating that the enhancement of BF on asphalt mixtures is related to the type of aggregate gradation. (3) BFs in the asphalt mixture lap each other to form a spatial network structure. Such structure can effectively improve the crack resistance of the mixture by dispersing the load stress and preventing the flow of asphalt mastic. The study results provide an effective method to design crack-resistant asphalt mixtures.     

兔耳前边缘静脉的类内皮细胞扫描电镜结构

目的观测新发现的兔耳前边缘静脉类内皮细胞扫描电镜结构。方法取日本大耳白兔耳前边缘静脉,常规制备扫描电镜样本,对新发现的类内皮细胞结构做扫描电镜观察。结果在兔耳前边缘静脉内皮细胞与基膜之间存在类似内皮细胞样结构,分布于血管干和属支开口处。每个类内皮细胞呈椭圆形或树叶状,最大长径(8.32±1.04)μm,最大宽径为(5.79±0.68)μm,长径/宽径比值为1.45±0.22,其长轴与血管纵轴呈平行排列。细胞之间以线状结构相连成“串珠”样,且线状结构将细胞压成凹陷或其末端嵌入细胞内;相邻两个细胞间的线长(6.41±2.45)μm。结论兔耳前边缘静脉内膜含有类内皮细胞结构;以线状结构相连也是细胞间连接方式之一。     

144例显微根尖外科手术疗效观察及分析

目的通过对显微根尖手术后患者临床随访评估,探讨显微根尖手术的成功率以及相关预后影响因素,为无法行根管治疗的复杂根尖周病的治疗提供参考。方法对2012—2014年底在我院行显微根尖手术的144例患者进行1年随访,收集患者主观症状、临床检查以及拍摄根尖X线片相关资料,综合评估显微根尖手术疗效,并统计分析性别、年龄及牙位预后影响因素。结果对144例患者共190颗患牙相关资料进行分析,1年有效率达92.63%(176颗),无效率为7.37%(14颗)。统计学分析结果显示患者的性别、年龄及牙位分布对显微根尖外科手术的预后无明显影响。结论显微根尖外科手术可以有效治疗复杂根尖周病变的有效方法,值得临床推广。     

磁性附着体静磁场对人牙周膜细胞骨架影响的研究

目的 研究牙科磁性附着体静磁场对人牙周膜细胞骨架的影响.方法 采用细胞静磁场加载装置,模拟磁性附着体静磁场,对体外培养的人牙周膜细胞加载10 mT、120 mT静磁场12～60 h,采用激光扫描共聚焦显微镜观察细胞骨架形态,图像分析软件测定分析细胞面积、长宽比以及微丝蛋白(F-actin)含量.结果 加载10 mT、120 mT静磁场12～60 h后,随加载强度和加载时间增加,细胞微丝骨架变短,排列紊乱,细胞长宽比减小(P＜0.05),加载静磁场60 h后细胞面积减小(P＜0.05),加载12 h后F-actin含量较对照组下降(P＜0.05),而加载36、60 h后与对照组之间差异无统计学意义(P＞0.05).结论 磁性附着体静磁场在本实验条件下能使人牙周膜细胞细胞骨架发生一定程度的改变.