Solidification process of conventional superalloy by confocal scanning laser microscope

The solidification process of a conventional superalloy, IN718, was investigated by confocal scanning laser microscope （CSLM）. The liquid fraction during solidification was obtained as a function of real time and temperature in reference with the in-situ observation. The characteristics of L→γ transformation were analyzed and the γ growing rate of each stage was also calculated. Scheil equation was employed to predict the segregation behavior, and the predict results are in consistence with the experimental results. As a result, the confocal scanning laser microscope shows a great potential for solidification process research.

In situ observation of the dissolution kinetics of Al_(2)O_(3) particles in CaO–Al_(2)O_(3)–SiO_(2) slags using laser confocal scanning microscopy

The dissolution kinetics of Al_(2)O_(3) in CaO-Al_(2)O_(3) SiOslags was studied using a high-temperature confocal scanning laser microscope at 1773 to 1873 K.The results show that the controlling step during the Al_(2)O_(3) dissolution was the diffusionin molten slag.It was found that the dissolution curves of Al_(2)O_(3) particles were hardly agreed with the traditional boundary layer diffusion model with the increase of the CaO/Al_(2)O_(3) ratio of slag.A modified diffusion equation considering slag viscosity was developed to study the dissolution mechanism of Al_(2)O_(3) in slag.Diffusion coefficients of Al_(2)O_(3) in slag were calculated as 2.8×10to 4.1×10m~2/s at the temperature of 1773-1873 K.The dissolution rate of Al_(2)O_(3) increased with higher temperature,CaO/Al_(2)O_(3),and particle size.A new model was shown to be v_(Al_(2)O_(3))=0.16×r_(0)^(1.58)×x^(3.52)×(T-T_(mp))^(1.11)to predict the dissolution rate and the total dissolution time of Al_(2)O_(3) inclusions with various sizes,where vAl_(2)O_(3) is the dissolution rate of Al_(2)O_(3) in volume,μm^(3)/s;x is the value of CaO/Al_(2)O_(3) mass ratio;R_(0) is the initial radius of Al_(2)O_(3),μm;T is the temperature,K;T_(mp) is the melting point of slag,K.

Confocal Laser Scanning Microscope Evaluation of Early Bacterial Colonization on Zirconium Oxide and Titanium Surfaces:An in vivo Study

To investigate the bacterial colonization on zirconium oxide and titanium surfaces in vivo quantitatively using a confocal laser scanning microscope （CLSM）. Ten samples of zirconium oxide ceramic and commercially pure titanium were fabricated and polished using silicon carbide abrasive paper. One sample from each group was evaluated topographic pattern under a scanning electron microscope. One sample from each group was to evaluate roughness using a profilometer. Eight volunteers were selected. The samples were cemented at the buccal surfaces of upper first molars. All samples were removed after 48 hours, immersed in SYTO-9 and propidium iodide fluorescent to stain for adherent bacteria and obseIved with CLSM. Fewer bacteria were observed in zirconia group than titanium group. However, there was no statistical difference between two groups. The experimental results demonstrate that zirconium oxide may be considered as a promising material for dental implant abutments.

Quantum Dots as Fluorescent Labels for Detection of Heat Shock Protein in Tumor Tissue Using Laser Scanning Confocal Microscope

A new Quantum Dots（Qdots） nanocrystal composed of semiconductor core and zinc sulfide shell, and its feasibility as labels in immunofluorescence analysis for the imaging of tumor biomarkers by laser scanning confocal microscope（LSCM） was investigated. Qdots taged by mercaptoacetic acid were conjugated with second antibody, then imaging differences of Heat Shock Proteins 70（HSP70） in renal carcinoma tissure sections with immunofluorescence analysis method using Qdots bioconjugates and conventional organic dye FITC were observed by LSCM to assess the brightness and opticalstability of Qdots. The experimental results showed Qdots bioconjugates achieved the better results in demonstrating HSP70 with more brighter color and more clear picture than FITC labels. Moreover, the label signals of Qdots did not fade clearly after continued exposure to a 488 nm laser for 1 h. The Qdots bioconjugates have good feasibility in immunofluorescence analysis for the bioimaging by LSCM.

Qualitative analysis of re mineralized carious lesions subjected to fluoride supplement through confocal laser scanning microscope

Aim: 1] Comparative evaluation of the linear depth of induced remineralized lesions after subjecting to fluoride supplements and 2] To assess the average fluorescence at both the demineralized and the remi-neralized zones in all the three study groups under confocal laser scanning microscope. Method: Forty five sound human premolars extracted for orthodon-tic reasons were decoronated 1 mm below the ce-mento-enamel junction and coated with nail varnish except for a 3 × 3 mm window on the buccal surface. The samples were placed in 50 ml of de mineralizing solution at pH 4.6 for 96 hours. Following deminera-lization, the lower half of the 3 × 3 mm window in all the samples were covered with nail varnish to serve as control. The samples were randomly divided into three groups of fifteen teeth each (n = 15) and speci-mens in group A[Nfd] were remineralized using non-fluoridated dentifrice [control], those in groups B [Fd5] and group C [Fd10] using 500 ppm and 1000 ppm of fluoride containing dentifrice, respectively. The specimens were subjected to a 20 day reminera-lization treatment regimen and were sectioned into 100 μm thick sections and two images were captured on the buccal surface from either side of the midpoint of occluso-cervical length using confocal laser scan-ning microscope [CLSM]. Results: were tabulated and statistically analyzed by Anova. Study concluded that 1000 ppm fluoridated dentifrice showed a greater degree of remineralization than other groups and confocal laser scanning microscopes gives promising results in the diagnosis of early enamel lesions over the conventional methods.

枯草芽孢杆菌无细胞上清液抑制单增李斯特菌生物被膜形成的研究

单增李斯特菌(Listeria monocytogenes)是一种常见的食源性致病菌,其生物被膜是导致食品污染和疾病传播的重要原因。该研究选用枯草芽孢杆菌(Bacillus subtilis)无细胞上清液(cell free supernatant,CFS)作为抑制剂,探究B.subtilis CFS在抑制L.monocytogenes野生菌株118(以下简称No.118)生物被膜方面的作用和潜力。首先测定了B.subtilis CFS的最小抑菌浓度(minimum inhibitory concentration,MIC),接着采用结晶紫染色法测定了不同亚最小抑菌浓度下B.subtilis CFS对No.118的生物被膜抑制率,发现不同亚抑菌浓度下的CFS对No.118生物被膜均具有显著的抑制作用,且在1/64 MIC时生物被膜抑制率仍可达到47%;同时B.subtilis CFS对No.118生物被膜代谢活性、自聚集率、表面疏水性、群集泳动能力和膜外聚合物分泌也均有显著抑制作用;最后,通过激光共聚焦显微镜观察了在CFS作用下,No.118生物被膜结构和细胞分布的变化规律,经CFS处理后,No.118生物被膜结构松散,细菌数量明显减少。综上,B.subtilis CFS可通过影响No.118生物被膜细胞的代谢活性、自聚集能力和群集泳动能力以及膜外聚合物的分泌来抑制其生物被膜形成,对探究益生菌代谢产物作为生物被膜抑制剂方面的应用具有重要的参考价值。

激光扫描共聚焦显微镜(LSCM)在植物细胞学中的应用

激光扫描共聚焦显微镜(LSCM)有效地排除了非焦平面信息,提高了分辨率及对比度,使图像更为精确清晰。目前已广泛应用于植物细胞学研究,在植物药研究方面有着广阔的应用前景。综述近年来的相关研究以反映其最新进展。

LSCM观察三七总皂甙及其组分对游离钙离子影像变化的影响

用盖玻片或ＭａｔＴｅｋ培养皿培养猪主动脉内皮细胞（ａＥＣ）约１８ｈ后，以荧光探针（ｆｌｕｏ－３／ＡＭ终浓度１０μｍｏｌ·Ｌ－１）负载，当细胞内游离钙离子（Ｃａ２＋）与ｆｌｕｏ－３结合后，通过激光扫描共聚焦显微镜（ＩｎＳＩＧＨＴ－ｐｌｕｓＩＱ型）观察细胞的荧光影像变化。基于三七总皂甙（ｔ－ＰＮＳ）对ａＥＣ所产生的生物活性物质有明显的作用，本拟进一步探索上述药物对ａＥＣ中［Ｃａ２＋］；的影响。实验结果显示：在ＡＴＰ作用后，ｔ－ＰＮＳ可使ａＥＣ内的荧光强度在２０～８０ｓ内急剧升高至峰值。但其组分Ｒｂ１及Ｒｇ１使荧光强度有下降或无明显变化。提示ｔ－ＰＮＳ有使内皮细胞［Ｃａ２＋］；升高的作用。

激光共聚焦显微镜应用于本科生的实验教学设计

激光共聚焦显微镜等大型仪器的实验教学是实现“新工科”建设的重要推动力,然而目前针对本科生的大型仪器教学却未得到有效普及。通过选取适合于本科生实践操作的微生物荧光染色观察实验以及基于“雨课堂”进行线上线下教学,发挥激光共聚焦显微镜可视化强的特点,激发本科生的求知欲望和探索热情,增强学生的主观能动性,促进以教师为主导向以学生为中心的教学模式转变。实践教学表明,易于操作、可视化强的实验方案有助于学生理解和掌握激光共聚焦显微镜相关的基础知识和未来应用,拓宽学生的知识面和科研视野,提高本科生的实践创新能力。

尼康共聚焦显微镜使用的大数据分析

激光共聚焦显微镜是目前最精密的光学成像仪器,是生命领域重要的研究工具。兰州大学生命科学研究实验中心的尼康共聚焦显微镜两年多时间工作了1万多小时,获取了大量的观测数据。对使用记录的分析表明,仪器在每天上午9点到晚上22点处于饱和工作状态,只有在寒假期间有所降低,说明了全天候开放使用的必要性。观测结果分析得到了很多有价值的信息,例如,488 nm和561 nm激光器使用率都超过了三分之一,单激光和双激光观测占比分别是72%和24%,高灵敏检测通道使用率接近90%等。综合这些信息,可以为共聚焦显微镜的管理和培训提供科学的依据。

低氧缺血海马神经元内Ca^(2+)动态变化的LSCM测定

测定脑组织细胞内 Ｃａ^(2+)浓度是评价缺血引起神经元损伤的重要指标。本研究用激光扫描共聚焦显微镜（ＬＳＣＭ）和Ｆｌｕｏ－３／ＡＭ荧光探针标记技术，从单个活细胞水平检测缺血刺激诱发的海马神经元内Ｃａ２＋瞬间动态变化。结果显示低氧使胞内Ｃａ２＋浓度显著升高。谷氨酸引起Ｃａ２＋浓度升高缓慢但持续时间长。缺血对Ｃａ２＋浓度影响不显著。撤除葡萄糖则引起胞内Ｃａ２＋迅速降低。实验结果表明不同缺血刺激因素引起的钙振荡各异。用ＬＳＣＭ对活细胞内部非侵入光学断层扫描，能清晰记录到这些瞬态钙值变化。

激光共聚焦显微镜荧光漂白后恢复实验的制样优化

利用激光共聚焦显微镜进行荧光漂白后恢复(FRAP)实验为研究分子的流动性提供了新的手段。然而,在拟南芥根毛细胞中进行荧光漂白后恢复实验时,由于拍摄时长的影响经常会导致样品脱离原来的焦平面,从而无法获得可靠的数据。以拟南芥根尖为材料,通过实验比较激光共聚焦显微镜下的常规制片、指甲油封片以及甘油制片,结果表明,利用指甲油封片能更好地解决样品离焦问题,可以获取有效的实验数据。

基于LSCM的线扫描方向识别方法的建立与应用

激光扫描共聚焦显微镜(LSCM)具有高分辨率和高光学切片的成像能力,是生命科学研究不可或缺的工具。通常采用的XY或者XYZ扫描方式成像速度慢,限制了生物研究中快速现象的追踪。本文介绍了实时快速成像的XT线扫描模式,并建立线扫描方向的识别方法。制作荧光小球样本,经过荧光小球划出不同方向的线段,使线段的一端接近荧光小球的中心而另一端远离,对线段进行XT线扫描,根据荧光信号与两端距离的远近判断扫描方向。阐述了XT线扫描在Zeiss、Nikon和Olympus共聚焦显微镜中的具体操作方法,并比较了其线扫描方向的差异。本研究建立了一套确定线扫描方向的实用方法,该方法简便易操作,具有普遍适用性,可为显微成像从业者和研究者提供借鉴。

Cr含量对1000 MPa级高强钢熔敷金属组织演变的作用机制

设计开发了5种不同Cr含量的1000 MPa级高强钢埋弧焊材,采用丝极埋弧焊制备了Cr含量为0%~0.9%的熔敷金属,利用OM、SEM、TEM和CLSM等微观组织表征方法研究Cr含量对1000 MPa级高强钢熔敷金属组织演变的影响,并通过拉伸和冲击试验评估其力学性能.结果表明,1000 MPa级高强钢熔敷金属随着Cr含量提高,铁素体转变起始温度由723.3℃提高到740.2℃,贝氏体转变起始温度由470.2℃降低到458.5℃,铁素体转变温度区间扩大,高Cr熔敷金属中贝氏体转变速率较快,熔敷金属中针状铁素体和贝氏体铁素体增加,M-A组元由弥散分布逐渐呈链条状偏聚,先共析铁素体与残余奥氏体减少.熔敷金属冲击断裂形式由低Cr的韧性断裂向高Cr的准解理断裂转变,熔敷金属拉伸强度不断提高,相比于无Cr的熔敷金属,0.9%Cr的熔敷金属抗拉强度和屈服强度分别提高12.4%和17.0%,熔敷金属冲击吸收能量先提高后降低,在−40℃条件下,0.6%Cr的熔敷金属的低温韧性最高为84 J,熔敷金属Cr含量为0.6%时强韧性匹配效果最佳.

CLMS观察iRoot BP Plus对根尖倒充填封闭效果的体外研究

目的:观察iRoot BP Plus作为根尖倒充填材料封闭根尖的效果。方法:选取上下颌单直根管离体牙60颗,Reciproc blue机用单支镍钛锉预备根管,热牙胶连续波技术充填根管,超声工作尖对离体牙根尖区行倒预备。将离体牙随机分为三组,分别以iRoot BP Plus、MTA、3MZ350树脂行倒充填。体式激光共聚焦扫描显微镜观察倒充填后材料及牙体组织的颜色变化率。上述标本再次随机分为两个亚组,分别浸泡于2%亚甲基蓝溶液和1 g/L罗丹明B荧光染料中,48 h后分别在光学显微镜、扫描电镜和激光共聚焦显微镜下测量染料线性渗漏长度;测量材料与牙本质间的微间隙宽度,观察不同倒充填材料与根管壁间的微观结合形态;计算分析根尖区微渗漏荧光染色面积。通过定性和定量的方法研究不同倒充填材料对根尖封闭性能的影响。结果:iRoot BP Plus组倒充填后未发生明显颜色改变,美观性优于MTA组(P<0.05),但与树脂组比较差异无统计学意义(P>0.05)。iRoot BP Plus组染料渗漏长度较MTA组短(P<0.05),和MTA组染料渗漏长度比较差异无统计学意义(P>0.05)。三组微间隙宽度比较,iRoot BP Plus组<MTA组<树脂组(P<0.05)。三组微渗漏荧光染色面积比较,iRoot BP Plus组<MTA组<树脂组(P<0.05)。结论:iRoot BP Plus具有良好的根尖封闭性、密合性和美观性。

激光共聚焦显微镜样本制备在研究生实验教学中的应用

激光共聚焦显微镜是一种多功能、高分辨率、高效率的光学设备,在植物细胞结构中通过荧光探针标记相关基因,获得清晰的亚细胞定位信息,如细胞膜、细胞器等结构。以烟草为实验材料,在研究生实验教学中利用LSCM880激光扫描共聚焦显微镜观察烟草下表皮细胞,通过优化样本制作,最终获取清晰的图片。通过实验教学,学生掌握激光共聚焦显微镜的原理、样品制备及操作步骤,提高理论知识与实践操作相结合的能力,加强其对激光共聚焦显微镜的掌握及运用。

Dispersion of particles in the coatings characterized by laser scanning confocal micrscopy(LSCM) I:Vertical dispersion of particles in the coatings and the weathering property studied by orthogonal analysis method of LSCM

Two kinds of TiO2 filled epoxy coatings were designed and prepared to obtain pigments with different dispersion degrees of TiO2 particles.Laser scanning confocal microscope（LSCM）was used to investigate both the horizontal and vertical distributions of TiO2 particles in the coatings.The results indicated that TiO2 in the two samples shared considerable similarity in horizental dispersion,but exhibited great difference in vertical dispersion.TiO2 showed uniform vertical distribution in disp coating,wheras a gap about 1.1μm was found in the non-disp coating,which significantly influenced the surface optical properties of the coatings during weathering.Based on the confocal data,the model of dispersion of pigments in the coatings was proposed and the change of surface properties during weathering was predicted:the surface optical properties showed an initial decrease followed by a subsequent increase,which was in good agreement with the weathering data.

Using laser confocal scanning microscope to study ischemia-hypoxia injury in rat brain slice

The level of lipid peroxidation and cellular necrosis in rat living brain slices during brain ischemia-hypoxia injury have been observed using a laser confocal scanning microscope (LCSM) with double labeling of fluorescent probes D-399 (2, 7-dichlorofluorescin diacetate) and propidium iodide (Pl). The hypoxia and/or reoxygenation injury in rat brain slices is markedly decreased by pretreatment with L-NG-nitro-arginine (L-NNA) and N-acetylcysteine (NAC), showing that the nitric oxide (NO) and other free radicals play an important role in brain ischemia-hypoxia injury.

融合免疫荧光技术的共聚焦显微镜实验教学实践

为了建立完整的科研实验技能学习体系,构建了高效可行的实验教学课程,并对近年开展的激光扫描共聚焦显微镜技术实验教学课程内容和方法进行了优化和实践。课程将科学理论与实验技能有机结合,把间接免疫荧光技术融合到共聚焦显微镜实验教学中,克服大型成像仪器教学中时间和空间限制。该教学课程帮助学生掌握共聚焦显微镜技术原理、应用和实验方法,提高学生们的实验动手能力和科研素养。

超高分辨率激光扫描共聚焦显微镜的成像技术与应用

超高分辨率激光扫描共聚焦显微镜在生命科学研究领域中的应用日益广泛。该文以Zeiss LSM 880 Airyscan with STEDYCON超分辨率激光共聚焦显微镜为例,介绍了Airyscan技术和基于受激发射现象的超分辨技术(STED)的原理、应用和参数设置,以期能够为科研工作者究竟采用哪种模式进行图像采集提供参考,以获得最佳的成像效果。