铈在磷酸酶电镜细胞化学中的应用

在磷酸酶细胞化学反应中,酶作用于底物所产生的初级反应物为磷酸,日前常用铅为捕捉剂,与磷酸反应形成高电子密度的磷酸铅沉淀,在电镜下探测。由于铅捕捉剂对酶有一定抑制作用,而且容易产生非特异性反应,近年来人们开始寻找新的捕捉剂,其中铈是较理想的一种,我们采用这种新捕捉剂铈开展了CMP酶和G—6—P酶等磷酸酶的细胞化学反应,获得了较好的效果。铈为捕捉剂的电镜细胞化学基本方法和步骤与我们以前报道的铅法相同(见细胞生物学杂志7增:3-14),但细胞化学反应液配方不同。CMP酶细胞化学反应液内含有2mmol/LC-5′-MP、40mmol/L醋酸钠缓冲液(pH5.0)、2mmol/L氯化铈(CeCl_4)、5mmol/L氯化锰和     

肝细胞质膜Na^＋—K^＋—ATP酶细胞化学定位及其定量研究

家兔肝细胞质膜Ｎａ＾＋－Ｋ＾＋－ＡＴＰ酶的定位研究，采用对硝苯苯酚磷酸盐为底物，铈为捕捉剂，反应产物分布于肝细胞质膜窦状隙面、仙是面和胆小管区。用电镜Ｘ射线显微分析法胆小管区反应产物进行分析，从谱线上可见明显的ＰＫａ峰和ＣｅＬ峰，证明反应产物为磷酸铈。     

基于蓝宝石材料的微结构增透性能研究

针对传统熔石英激光窗口在碱金属蒸气环境下易腐蚀的痛点问题，提出了在蓝宝石材料上制备增透微结构的方法，以实现耐高温、耐腐蚀的高透激光窗口。在理论仿真的基础上，采用干涉曝光与反应离子束刻蚀技术，在蓝宝石基底表面上制备了增透微结构，其对795 nm光的单面透过率达到99.23%。在此基础上，制备了双面增透微结构和一面增透微结构一面增透膜的蓝宝石窗口片，相较于蓝宝石基底，它们对795 nm光的透过率分别提升了12.13%和13.02%。高功率激光作用温升测试结果表明，当激光功率从35 W增加到99.6 W时，裸基板温度增加了5.9℃，但是双面增透样品的温升均为3.8℃，表明双面增透处理可以适当降低温升。同时，光束质量测试结果表明，当高功率激光作用下微结构窗口的温度控制在200℃以内时，双面增透样品的光束质量因子在横向上的变化小于0.05，在纵向上的变化小于0.06，表明该增透窗口对入射光光束质量的影响甚小。     

红外增透薄膜新进展述评

本文综述了红外增透薄膜研究的一些新进展,其中包括宽带增透薄膜的多种设计和制备方法及具有优异性能的增透膜新材料的研究。     

氮激光从稀土混合物中分离铈的研究

用337.1 nm 的氮分子激光诱导溶液中的氧化反应,从混合稀土中分离出了铈稀土。用感应耦合等离子体原子发射光谱术对反应产物中的铈、镧等元素含量作了测定,得出铈相对于镧的分离系数值为:β=11.5。     

SiO2致肺巨噬细胞产生H2O2的电镜显示技术

目的：建立无机有毒粉尘颗粒致ＡＭｓ产生Ｈ２Ｏ２的电镜原位显示技术。方法：以铈离子为捕捉剂，于产生Ｈ２Ｏ２的原位形成过氢氧化铈沉淀。结果：Ｈ２Ｏ２的阳性反应呈线状高电子密度沉淀，分布于ＡＭｓ质膜、吞噬体／吞噬泡膜、及溶酶体膜。结论：无机有毒粉尘颗粒致ＡＭｓ产生的Ｈ２Ｏ２能够以电镜细胞化学方法于原位显示。该技术在显示氧自由基Ｈ２Ｏ２的同时，能同步观察细胞的超微结构。因而比自由基总体测定技术更能直观具体地体现ＡＭｓ与粉尘相作用的关系，是一项实用的实验室技术。     

红外墙透保护膜系软件设计及应用

根据制备红外增透保护膜系需要,编制了一个红外增透保护膜系软件。该软件可以设计、计算多层红外均匀增透保护膜系和非均匀增透保护膜系,更有强大多层膜系结构分析功能,不仅可以对设计的膜系进行综合评价,而且能对制备的膜系结构进行分析。实验结果表明,该软件对膜系设计和为制备工艺的改进能提供良好的指导。     

红外增透保护膜系软件设计及应用

根据制备红外增透保护膜系需要 ,编制了一个红外增透保护膜系软件。该软件可以设计、计算多层红外均匀增透保护膜系和非均匀增透保护膜系 ,更有强大多层膜系结构分析功能 ,不仅可以对设计的膜系进行综合评价 ,而且能对制备的膜系结构进行分析。实验结果表明 ,该软件对膜系设计和为制备工艺的改进能提供良好的指导     

蓝宝石衬底上二维亚波长增透结构的设计分析

利用等效介质理论、薄膜理论研究了二维亚波长结构的增透设计,以蓝宝石衬底为例,研究了二维亚波长结构的增透设计,分析了该结构的周期、占空比、高度等参数对增透率的影响,通过分析找到了合适的结构参数.结果表明,当二维亚波长结构的等效折射率等于增透镀层材料的折射率、刻蚀高度等于单层理想增透膜的厚度时,这种结构具有良好的增透效果.采用蓝宝石双面设计二维亚波长结构后,在3μm-5μm波段的平均透过率可达99.25%.     

兔大脑皮质单个神经元酶的扫描电镜能谱分析

一般酶活性的超微结构定位都用透射电镜进行观察。用扫描电镜观察酶活性定位、并结合X-射线微区分析鉴定酶反应特异性的报道极少。我们采用铈-铅-银法对分离的兔额叶大脑皮质单个神经元进行5’-核苷酸酶和p-NPP酶反应,用光镜和扫描电镜观察酶反应定位,并用X-射线微区分析(EDAX 9100能谱仪)鉴定酶反应的特异性,取得了较好的结果。兔大脑额叶皮层经固定和酒精分化,在盖玻片上分离出单个神经元,进行5’-核苷酸酶和p-NPP酶铈法反应,又进行铈-DAB法、铈-铅法和铈-铅-银法处理,从而在光镜下能观察到神经细胞质膜和突起的膜上所显示的5,-核苷酸酶和p-NPP酶阳性反应部位,其中以后者处理的样品显示出最强的酶反应     

小麦幼苗质膜Mg2+-ATP酶活性与低温损伤及其恢复的关系

采用氯化铈(CeCl3)沉淀的电镜细胞化学方法观测了小麦(Triticum aestivum L.)幼叶细胞质膜三磷酸腺苷酶活性在低温胁迫后、恢复过程中以及恢复后的变化.所得主要结果如下 :(1)在正常温度(20℃)下生长的小麦幼苗,其幼叶细胞内的三磷酸腺苷酶主要定位于质膜、细胞壁和细胞间隙等处,其中以质膜上的酶活性最强.(2)小麦幼苗在-2℃处理16h后未经恢复生长即固定,此时质膜上的ATPase活性明显降低或失活,细胞的超微结构也受到破坏.(3)小麦幼苗经-2℃低温胁迫16h后,并经过24h的恢复生长,此时质膜的ATP酶活性有了很大程度的恢复;小麦幼苗在-2℃低温下处理16h后,经150mmol/L CaCl2溶液处理,并经24h的恢复生长,此时质膜上的ATP酶活性比未用CaCl2处理时增强;小麦幼苗经-2℃低温处理16h后,经100mmol/L Na3VO4(钒酸钠)处理,也经过24h的恢复生长,此时质膜上观察不到ATPase的活性反应,同时细胞的超微结构受到严重破坏.(4)小麦幼苗在-2℃处理16h后,经过72h的恢复生长,质膜上的ATPase活性基本恢复到正常水平,同时小麦幼苗也基本恢复正常生长.     

心肌细胞内SOD定位的电镜观察

利用心肌组织缺氧再灌注方法，已获得心肌细胞超氧化物歧化酶（ＳＯＤ）活性定位的证据，是通过Ｂｒｉｇｇｓ等人介绍的铈方法，用电子组化来研究的。羟基过氧化铈的形成作为ＳＯＤ活性的一种指示剂，其结果表明：（１）ＳＯＤ活性位置存在于心肌细胞浆基质及一些线粒体内，而细胞核及其它细胞器内未见同类标记物。（２）羟基过氧化铈可作为心肌细胞内ＳＯＤ的一种定位指示剂。     

Cytochemical energy-filtering transmission electron microscopy of mitochondrial free radical formation in paraquat cytotoxicity.

The generation of oxygen free radicals was investigated using cytochemistry and its energy-filtering transmission electron microscopy in reference to the toxic mediator for the herbicide paraquat. When isolated intact mitochondria from rat livers were incubated in a medium containing paraquat and NADH, a mitochondrial NADH-quinone oxidoreductase activity generated superoxide anions to cause the destruction of mitochondria which resulted in cell death. The superoxide anions were immediately converted into hydrogen peroxide, which then formed cerium perhydroxide deposits in the presence of cerium ions and precipitated on the outer surface of the mitochondrial outer membrane. This localization was also specifically identified by energy spectral imaging and image-electron energy loss spectral analyses. Precipitation reaction was scavenged by the addition of either cytochrome c or catalase and inhibited by dicoumarol (an inhibitor of NAD(P)H-quinone oxidoreductases). These cytochemical energy-filtering transmission electron microscopic results indicated that paraquat generated free radicals from the outer membrane of mitochondria.     

Cerium-doped fluoride lasers

In the 30 years since tunable ultraviolet (UV) lasers based on 5d /spl rarr/ 4f transition of trivalent lanthanides doped into solid-state hosts were first demonstrated, tremendous progress has been made in these unique laser systems. Today, cerium-doped fluoride lasers offer wide tunability (280-333 nm), high efficiency (up to 62%) and narrow-band output. These lasers can also be used for femtosecond pulse amplification in the UV. Cerium lasers represent a logical route to generation of tunable UV in all-solid-state systems. In this paper, we review the current state-of-the-art cerium laser crystal development and cerium laser systems.     

Bulk heterojunction thin film formation by single and dual feed ultrasonic spray method for application in organic solar cells

We here present a way of preparing the polymer:fullerene BHJ using dual feed method which can lead to formation of pure phases. In this report, we present results of our initial experiments in this direction. The effect of process parameters on the thickness and surface roughness of the active layer has been discussed. The structural and optical properties have been studied using the optical microscope, UV-visible spectroscopy and photoluminescence spectroscopy. Significant PL quenching indicates efficient charge separation in the BHJ formed using this technique. We have also compared the BHJ thin films prepared with this dual feed ultrasonic technique with the single feed spray method. The BHJ formed using this technique has been used as an active layer in OSC.     

显示弹性纤维系统的一种鞣酸细胞化学染色方法

弹性纤维是结缔组织中的一种重要成分。弹性纤维系统包括三种不同类型的纤维,分别称为弹性纤维、前弹性纤维及耐酸纤维。用常规透射电镜制备方法只能显示弹性纤维,而且其电子密度及反差均不够理想。如在电镜标本的制备过程中,加入鞣酸则能很好地显示弹性纤维的两种成分及三型纤维。鞣酸加入戊二醛固定液或鞣酸加入醋酸铀染色液的方法,均已有过报道,作者对常规固定的标本,在染色前用鞣酸处理,获得良好的效果,现介绍如下。     

Optical phase conjugation (OPC) for focusing light through/inside biological tissue

Optical phase conjugation(OPC) is a technique that generates a light field with reversed wavefront and identical amplitude distribution as the incident light. It has a unique feature of suppressing the aberration of incident beam induced by inhomogeneous or disturbing medium. Although this technique has been extensively studied since the 1970s, it has become more attractive because of unprecedented achievements and prospective potentials in biomedical applications. OPC-based techniques have been successfully utilized to form a focus through/inside highly scattered biological samples. It opens a new avenue by significantly enhancing the light delivery in biological tissue for high-resolution imaging, diagnosis and treatment of medical diseases. In order to provide insight into its further development, recent progress of OPC techniques for focusing light through/inside biological tissue was summarized.     

Novel synthesis of cerium oxide nano photocatalyst by a hydrothermal method

Crystalline cubic cerium oxide nano particles have been synthesized from cerium (Ⅲ) nitrate (Ce (NO3)3.6H2O) and sodi-um hydroxide by a hydrothermal method.The effect of three different molar ratios of the NaOH precipitating agent on structur-al,optical,and photo catalytic activity was investigated.The synthesized cerium oxide nano particles were characterized by X-ray diffraction (XRD),a UV-vis spectrometer,scanning electron microscope (SEM),energy-dispersive X-ray spectroscopy (EDAX),Raman spectroscopy and X-ray photo electron spectroscopy (XPS).According to the findings,hydrothermally synthesized ceri-um oxide NPs have a high efficiency for photocatalytic degradation of methylene blue when exposed to UV light.Environment-al water pollution is the major issue of the atmosphere.To get fresh water,humans could search the resources to purify the wa-ter in simple way and degradation is the one of the methods to purify salt water.     

Synthesis and characterization of cerium oxide nano-particles in chloride bath: Effect of the H2O2 concentration and bath temperature on morphology

Cerium oxide has been used extensively for various applications over the past two decades. The use of cerium oxide nanoparticles is beneficial in present applications and can open new avenues for future uses. In this paper, some samples of cerium hydroxide/oxide have been synthesized by cathodic deposition on steel electrode in chloride bath in two electrode systems by the galvanostatic mode. The effects of bath temperature and H₂O₂ concentration on particle size and morphology were studied. The effect of calcination temperature on the crystallite growth of cerium oxide nano-powders was investigated by X-ray diffraction. The results were characterized by the differential scanning calorimetry (DSC), thermogramimetric analysis (TGA), X-ray diffraction (XRD), and scanning electron microscopy (SEM). The SEM results show that the samples synthesized at low bath temperature have an average size of 40 nm. In the presence of H₂O₂, the cerium oxide films are adherent and smooth. They present very thin cracks whereas with the increase of H₂O₂ concentration the size and number of cracks are reduced. The results show that the as-prepared nanoparticles are essentially amorphous and after heat treatment, the obtained oxide product is well crystallized.     

高功率半导体激光器端面泵浦Nd:YVO_4固体激光器热致损耗的研究

本文提出了一种测量端面泵浦固体激光器热致损耗的方法．研究了Ｎｄ（３＋）浓度分别为０．５％和２％两种Ｎｄ：ＹＶＯ４晶体,基模半径与泵浦光斑半径之比Ｗ１／Ｗｐ分别为０．５和１情形下热致损耗随泵浦功率的变化,结果表明：热致损耗随泵浦功率的增加而增大,且强烈依赖于Ｗ１／ＷＰ;大的基模半径会导致严重的热致损耗．Ｎｄ：ＹＶＯ４晶体的Ｎｄ３＋浓度对热致损耗也有很大影响,在大模半径情形,高浓度晶体的热致损耗远大于低浓度晶体,而且对于Ｗ１／Ｗｐ的依赖更为强烈．