Micro-computerized Three-dimensional Reconstruction of the Palmar Arteries and Its Clinical Significance

Thirty adult upper extremities were used to study the arteries of the hand byangiography,cross-sectional dissection and three-dimensional reconstruction withmicrocomputer.The arterial skeleton of the palm was composed of superficial,deep anddorsal planes.There were three main anastomotic pathways between the radial and ulnararteries or their branches in the radio-ulnar direction,while in the palmar dorsal dirce-tion there were three anastomotic zones between the palrnar and dorsal arterial plancs.The branches of the deep palmar arch radiated distally,proximally,palmarly anddorsally,so that the arch acted as the center of the arterial network of the hand.Thetransverse arterial allocations in the carpo-metacarpal segment of the palm were four intypes,but in the mid-palmar and metacarpo-phalangcal segments were three only.Accord-ing to the sources,cross-sectional area,irrigation territories and anastomoses of the ar-teries in each segment,the clinical significance in the rcplantation of the amputatcd palmshas been

Micro-Computed Tomography Applications in Dentistry

Micro-computed tomography (MCT) encompasses two primary scanning options: ex-vivo and in-vivo imaging. Ex-vivo scanning involves the examination of extracted teeth or dental specimens, allowing for detailed analyses of the microarchitecture of mineralized tissue. By analyzing the microarchitecture of dental tissues, MCT can provide valuable information about bone density, porosity, and microstructural changes, contributing to a better understanding of disease progression and treatment outcomes. Moreover, MCT facilitates the quantification of dental parameters, such as bone volume, trabecular thickness, and connectivity density, which are crucial for evaluating the efficacy of dental interventions. This present study aims to comprehensively review and explore the applications of MCT in dentistry and highlight its potential in advancing research and clinical practice. The results depicted that the quantitative approach of MCT enhances the precision and reliability of dental research. Researchers and clinicians can make evidence-based decisions regarding treatment strategies and patient management, relying on quantifiable data provided by MCT. The applications of MCT in dentistry extend beyond research, with potential clinical implications in fields such as dental implantology and endodontics. MCT is expected to play an increasingly significant role in enhancing our understanding of dental pathologies, improving treatment outcomes, and ultimately, benefiting patient care in the field of dentistry.

Comparative study of chitosan/fibroin–hydroxyapatite and collagen membranes for guided bone regeneration in rat calvarial defects: micro-computed tomography analysis

This study aimed to utilize micro-computed tomography （micro-CT） analysis to compare new bone formation in rat calvarial defects using chitosan/fibroin-hydroxyapatite （CFB-HAP） or collagen （Bio-Gide） membranes. Fifty-four （54） rats were studied. A circular bony defect （8 mm diameter） was formed in the centre of the calvaria using a trephine bur. The CFB-HAP membrane was prepared by thermally induced phase separation. In the experimental group （n= 18）, the CFB-HAP membrane was used to cover the bony defect, and in the control group （n= 18）, a resorbable collagen membrane （Bio-Gide） was used. In the negative control group （n= 18）, no membrane was used. In each group, six animals were euthanized at 2, 4 and 8 weeks after surgery. The specimens were then analysed using micro-CT. There were significant differences in bone volume （BV） and bone mineral density （BMD） （P〈O.05） between the negative control group and the membrane groups. However, there were no significant differences between the CFB-HAP group and the collagen group. We concluded that the CFB-HAP membrane has significant potential as a guided bone regeneration （GBR） membrane.

Investigating microstructure of Longmaxi shale in Shizhu area,Sichuan Basin, by optical microscopy, scanning electron microscopy and micro-computed tomography

Microstructure of shale formation is the key to understanding its petrophysical and chemical properties.Optical microscopy, scanning electron microscopy and micro-computed tomography(μ-CT) have been combined for characterization of microstructure of Longmaxi(LMX)shale from Shizhu area, Sichan Basin. The results indicate that laminated LMX shale consists of mineral matrix-rich layers and organic matter(OM)-rich layers at micrometer scale in two and three dimensions. Mineral matrix layers,mainly consisting of interparticle pores and intraplatelet pores, are approximately parallel to the bedding plane.Pyrite-rich layer, mainly containing intercrystalline pores,shows a strong preferred orientation parallel to the bedding plane. OM-rich layer, mainly containing OM pores, seems to be discontinuous. In addition, intercrystalline pores are enriched in some layers, while OM pores are distributed irregularly in matrix layers. This vertical heterogeneity of pore microscopic structures in LMX shale is of great importance to understand its petrophysical and chemical properties.

Nondestructive Skeletal Imaging of Hyla suweonensis Using Micro-Computed Tomography

We successfully obtained 3D skeletal images of Hyla suweonensis, employing a nondestructive method by applying appropriate anesthesia and limiting the radiation dose. H. suweonensis is a tree frog endemic to Korea and is on the list of endangered species. Previous studies have employed caliper-based measurements and two-dimensional （2D） X-ray imaging for anatomical analyses of the skeletal system or bone types of H. suweonensis. In this work we reconstructed three-dimensional （3D） skeletal images of H. suweonensis, utilizing a nondestructive micro-computed tomography （micro-CT） with a short scan and low radiation dose （i.e. 4 min and 0.16 Gy）. Importantly, our approach can be applied to the imaging of 3D skeletal systems of other endangered frog species, allowing both versatile and high contrast images of anatomical structures without causing any significant damages to the living animal.

Contrast-enhanced micro-computed tomography using Exi Tron nano6000 for assessment of liver injury

AIM: To explore the potential of contrast-enhanced computed tomography(CECT) using Exi Tron nano6000 for assessment of liver lesions in mouse models.METHODS: Three mouse models of liver lesions were used: bile duct ligation(BDL),lipopolysaccharide(LPS)/D-galactosamine(D-Gal N),and alcohol.After injection with the contrast agent Exi Tron nano6000,the mice were scanned with micro-CT.Liver lesions were evaluated using CECT images,hematoxylin and eosin staining,and serum aminotransferase levels.Macrophage distribution in the injury models was shown by immunohistochemical staining of CD68.The in vitro studies measured the densities of RAW264.7 under different conditions by CECT.RESULTS: In the in vitro studies,CECT provided specific and strong contrast enhancement of liver in mice.CECT could present heterogeneous images anddensities of injured livers induced by BDL,LPS/D-Gal N,and alcohol.The liver histology and immunochemistry of CD68 demonstrated that both dilated biliary tracts and necrosis in the injured livers could lead to the heterogeneous distribution of macrophages.The in vitro study showed that the RAW264.7 cell masses had higher densities after LPS activation.CONCLUSION: Micro-CT with the contrast agent Exi Tron nano6000 is feasible for detecting various liver lesions by emphasizing the heterogeneous textures and densities of CECT images.

Microstructure Study of Normal Lunates with Micro-computed Tomography

In order to study the microstructure characteristics of normal lunate bones, eight fresh cadaver normal lunates were scanned with micro-computed tomography. High-resolution images of the micro-structure of normal lunates were obtained and we analyzed the nutrient foramina. Then nine regions of interest(ROI) were chosen in the central sagittal plane so that we could obtain the parameters of trabecular bones of ROIs. The distal lamellar-like compact structure had statistically significant differences when it was compared with the ROIs in the volar and dorsal ends of the distal cortex. The difference of diameter between the volar and dorsal foramina was significant(P<0.05). However, there was no significant difference regarding the number. The trabecular bones of the volar and dorsal distal ends had lower intensity than those of the distal central subchondral bone plate. The diameters of the nutrient foramina on the volar cortex were larger than those on the dorsal. This research provided more detailed information about microstructure of normal lunate and the nutrient foramina on cortex, and a reference for further study about diseased lunate.

Monitoring vascular changes induced by photodynamic therapy using contrast-enhanced micro-computed tomography

The aim of this study was to determine whether contrast-enhanced micro-computed tomography can be used for non-invasive imaging of the early-stage changes in the vasculature of tumours that have been treated with photodynamic therapy (PDT). The subjects used were C3H mice with an RIF-1 tumour implanted subcutaneously and allowed to grow for 3 weeks prior to treatment. The experimental groups were PDT-treated (150 J/cm2 and 50 J/cm2) and control (150 J/cm2 light-only and untreated). The laser light exposure was performed at 15 - 30 minutes after the administration of the photosensitizer (BPD-MA). The contrast-enhanced micro-computed tomography imaging procedure consisted of eight-second scans taking place before treatment and up to 24 hours after treatment. The 150 J/cm2 PDT group showed a significant increase in the ratio of blood volume to tumour volume at 2, 8 and 24 hours after treatment when compared to pre-treatment measurements (p 2 PDT group at 24 hours after treatment. This preliminary study indicates that micro-CT can detect compromised vasculature in tumours treated with high-fluence photodynamic therapy as early as 2 hours post treatment.

Micro-computed tomography assessment of human femoral trabecular bone for two disease groups(fragility fracture and coxarthrosis):Age and gender related effects on the microstructure

The aim of this study was to identify three-dimensional microstructural changes of trabecular bone with age and gender, using micro-computed tomography. Human trabecular bone from two disease groups, osteoporosis and osteoarthritis was analyzed. A prior analysis of the effects of some procedure variables on the micro-CT results was performed. Preliminary micro-CT scans were performed with three voxel resolutions and two acquisition conditions. On the reconstruction step, the image segmentation was performed with three different threshold values. Samples were collected from patients, with coxarthrosis (osteoarthritis) or fragility fracture (osteoporosis). The specimens of the coxarthrosis group include twenty females and fifteen males, while the fragility fracture group was composed by twenty three females and seven males. The mean age of the population was 69 ± 11 (females) and 67 ± 10 years (males), in the coxarthrosis group, while in the fragility fracture group was 81 ± 6 (females) and 78 ± 6 (males) years. The 30 μm voxel size provided lower percentage difference for the microarchitecture parameters. Acquisition conditions with 160 μA and 60 kV permit the evaluation of all the volume’s sample, with low average values of the coefficients of variation of the microstructural parameters. No statistically significant differences were found between the two diseases groups, neither between genders. However, with aging, there is a decrease of bone volume fraction, trabecular number and fractal dimension, and an increase of structural model index and trabecular separation, for both disease groups and genders. The parameters bone specific surface, trabecular thickness and degree of anisotropy have different behaviors with age, depending on the type of disease. While in coxarthrosis patients, trabecular thickness increases with age, in the fragility fracture group, there is a decrease of trabecular thickness with increasing age. Our findings indicate that disease, age and gender do not provide significant differences in trabecular microstructure. With aging, some parameters exhibit different trends which are possibly related to different mechanisms for different diseases.

Three-Point Bending Test and Crack Detection by Acoustic Emission on Different Spring Steel Wires with Different Crystallographic Textures

In the production of compression springs,high forming velocities and grades of deformation during winding and setting may induce cracks that can lead to failure causing risks of an accident and damage.The AE(acoustic emission)technology,a non-destructive monitoring method,can detect acoustic signals reflected from cracks.To establish this method in the production of technical springs,it was necessary,to find out whether the AE signal is influenced by material properties,phase fractions distribution from tempered martensite,retained austenite,and microstructure including crystallographic texture.In addition,it was investigated to what extent the detected AE signal can be useful to separate between an actual crack and other material responses.Within an in-situ three-point bending test with the AE technology,macro-and micro-crack-typical AE signals were detected for five different spring steel wires(SH,VDSiCr,and FDSiCr according to EN-10270-1 and EN-10270-2).The relative energy related to the initiation,propagation,and growth of cracks caused by mechanical stress was measured using a piezoelectric sensor.If a crack AE signal appeared for the first time,the bending tests were stopped immediately.The results show that the frequency spectrum combined with the intensity of the acoustic signals generated during crack growth depends on the material properties and the crystallographic texture.Furthermore,it could be shown that it is possible to differentiate between micro-crack-typical AE signals and other signals that result from different material responses.

Influence of inter-grain cementation stiffness on the effective elastic properties of porous Bentheim sandstone

Effective elastic properties of porous media are known to be significantly influenced by porosity.In this paper,we investigated the influence of another critical factor,the inter-grain cementation stiffness,on the effective elastic properties of a granular porous rock(Bentheim sandstone)using an advanced numerical workflow with realistic rock microstructure and a theoretical model.First,the disparity between the experimentally tested elastic properties of Bentheim sandstone and the effective elastic properties predicted by empirical equations was analysed.Then,a micro-computed tomography(CT)-scan based approach was implemented with digital imaging software AVIZO to construct the 3D(three-dimensional)realistic microstructure of Bentheim sandstone.The microstructural model was imported to a mechanics solver based on the 3D finite element model with inter-grain boundaries modelled by cohesive elements.Loading simulations were run to test the effective elastic properties for different shear and normal intergrain cementation stiffness.Finally,a relation between the macroscale Young’s modulus and inter-grain cementation stiffness was derived with a theoretical model which can also account for porosity explicitly.Both the numerical and theoretical results indicate the influence of the inter-grain cementation stiffness,on the effective elastic properties is significant for porous sandstone.The calibrated normal and shear stiffnesses at the inter-grain boundaries are 1.2×10^(5) and 4×10^(4) GPa/m,respectively.

手掌部动脉的微型计算机三维重建及其临床意义

成人上肢标本30例,经肱动脉注入遮光色素,作手部动脉造影,然后制成连续的断面标本并摄影。应用微型计算机进行测量并三维重建动脉网。在各断面解剖追踪予以印证。手掌部的动脉由掌浅、掌深和掌背3个层次构成支架。在桡、尺方向上有3条大吻合支,掌、背方向上有3组吻合带,从而形成以掌深弓为中心的在三维空间6个方向都有动脉支连通的立体网络系统。在横断面上的配布型式,按主支的排列位置,在腕掌部可分四型,在掌中部和掌指部可各分为三型。根据动脉支的来源、口径、供区和吻合情况,讨论了腕掌、掌中和掌指3个部位的血供特点以及断掌再植时吻接动脉选择的主与次。

微机化站间自动闭塞系统的研究

分析以CAN总线控制技术为基础构成微机化站间自动闭塞系统的可行性 ,并提出其实现方案 ,包括系统结构与功能、系统工作原理和系统设计 ,同时进行微机化站间自动闭塞的安全控制逻辑分析 .

MicroCT定量研究去势大鼠颌骨与胫骨的骨改变

目的:应用MicroCT对Sprague-Dawley(SD)雌性大鼠去除双侧卵巢三个月后的下颌骨和胫骨进行对比研究。方法:分别从假手术对照(Sham)组和卵巢切除骨质疏松(OVX)组各取大鼠8只。将全部大鼠深度麻醉后处死。取一侧下颌骨和胫骨,去净软组织。行MicroCT检查、骨组织病理学研究。所得数据经SPSS13.0统计分析。结果:大鼠去除双侧卵巢3月后,经MicroCT检查发现,OVX组大鼠胫骨:骨小梁数目减少,排列稀疏,骨小梁断裂;骨小梁面积比和体积比、厚度和数目,骨矿含量和骨体积密度等均较Sham组显著降低,骨小梁分离度增加,P<0.05。OVX组大鼠下颌骨:骨组织体积比、骨小梁厚度和单位体积骨小梁数目,均比Sham组升高,骨小梁分离度较Sham组降低,P<0.05。与胫骨改变比较,结果完全相反。另外,大鼠下颌骨的三维骨矿含量和骨体积密度也升高,P<0.05。骨组织切片病理学观察:Sham组胫骨松质骨呈条索状,骨小梁相互连接成网;下颌骨松质骨较致密,呈板状。OVX组胫骨骨小梁变细,分离度增大,新生骨基质减少。磨牙下方松质骨骨髓腔增大,牙槽突新生骨基质减少。结论:SD雌性大鼠切除卵巢3月后,下颌骨与胫骨的骨改变有差异。OVX大鼠胫骨近心干骺端呈明显骨质疏松状态,与Sham组比较差异显著,MicroCT影像直观、三维指标差异显著。OVX大鼠下颌骨,与Sham组比较,骨量增加,结构致密,但已有骨生成减少表现。

阿仑膦酸钠与左旋精氨酸治疗骨质疏松大鼠的实验研究

目的:评估阿仑膦酸钠和左旋精氨酸治疗骨质疏松大鼠的疗效,初步探讨药物的作用机理。方法:从假手术对照(Sham)组取大鼠8只、卵巢切除骨质疏松(OVX)组取大鼠32只,分成4组分别给予阿伦磷酸钠皮下注射1.5mg/kg(周一、四给药)、和/或左旋精氨酸皮下注射10mg/kg(周一至五给药)。Sham组和OVX对照组给予生理盐水皮下注射。治疗一月后,取静脉血,将全部大鼠深度麻醉后处死。取一侧股骨和胫骨,去净软组织。行MicroCT检查、骨组织病理学及生物力学研究。所得数据经SPSS13.0统计分析。结果:OVX大鼠单独使用阿伦磷酸钠组、左旋精氨酸组的数据与Sham组比较无显著性差异,最大应力、弹性应力均明显好于OVX对照组。联合用药组与单独用药组数据有显著性差异。结论:三种用药均对OVX大鼠有明显的抗骨质疏松作用,阿伦磷酸钠、左旋精氨酸单独用药疗效好于联合用药。提示:联合用药可能过度抑制骨吸收,减少骨生成。

压缩荷载下煤岩损伤演化规律细观实验研究

利用计算机层析摄影技术 (CT)进行了单轴压缩荷载作用下脆性煤岩破坏全过程的细观损伤演化规律动态CT试验 ,得到了单轴荷载作用下各个应力阶段煤岩从微孔洞压密到微裂纹萌生、分叉、发展、断裂、破坏以及峰值后各个阶段清晰的CT图像和CT数 .根据实验结果可把白皎煤矿煤岩细观损伤演化规律全过程分为 5个阶段 :损伤弱化阶段、准线性阶段、损伤开始演化和稳定发展阶段、损伤加速发展阶段、峰后软化阶段 .通过对CT数及其方差进行分析 ,得到了单轴荷载作用下各个应力阶段煤岩的损伤演化规律 ,为从细观尺度探讨微裂纹的发生、发展提供了依据 .

X射线衍射仪微机化升级改造的讨论与实践

介绍一种旧型号的X射线衍射仪微机化的升级改造技术以及相应的数据采集与分析系统 (XRDS)。该系统将采集的衍射数据以文件形式存盘 ,并对该数据文件进行分析处理。结果可用图谱显示、打印、生成峰数据表、或扫描数据表等多种形式输出。原仪器记录系统仍可独立工作。系统结构简单 ,能充分利用仪器的机械精度 ,改造工作只需连接几对信号线便可完成 ,价格低廉 ,适用于任何旧型号的X射线衍射仪。

利用Micro-PET显像技术分析阿尔茨海默病小鼠模型的脑糖代谢

目的利用小动物PET(Micro-PET)影像技术18氟-脱氧葡萄糖(18 F-FDG)摄取率分析阿尔茨海默病(AD)小鼠模型的脑糖代谢,探索评价治疗AD药物的影像分析技术。方法正常对照组、APPswe/PSΔE9转基因模型组和安理申[2 mg/(kg.d)]治疗组小鼠共9只,自腹腔注射放射性示踪剂18F-FDG,采集脑部Micro-PET图像,通过软件IRW计算并比较各组小鼠大脑与额叶、颞叶感兴趣区(ROI)每克组织18 F-FDG的摄取率。结果利用18F-FDG的Micro-PET影像分析可以检测AD小鼠模型的脑糖代谢,并发现APPswe/PSΔE9转基因小鼠的脑糖摄取明显降低,与人类AD患者表现的脑糖摄取降低一致,安理申治疗可以提升APPswe/PSΔE9转基因小鼠的脑糖摄取。结论 18F-FDG Micro-PET影像分析可以用于小鼠AD模型脑葡萄糖代谢水平的检测,并可以作为阿尔茨海默病治疗药物提升脑糖代谢作用的分析技术。

基于“微课堂”云平台的设计与开发

微课堂下的信息化教学要求具备完整的微课教学资源、教学过程和教学反馈与评价.云平台能够根据用户需求提供高效的数据存储和计算服务,基于云平台的微课堂能够为不同用户提供教学和学习服务.文章结合微课堂的教学设计分析了云平台架构下微课堂教学平台的设计和构建.在云平台大规模运用的背景下,云平台架构的微课堂能够为教育教学信息化带来新的变革,为网络教学资源共享和更新带来更大的优越性.

X射线衍射仪升级改造的最简方案

介绍一种十分简单的旧型号X射线衍射仪微机化的升级改造技术以及相应的数据采集与分析系统(XRDS)。该系统将采集的衍射数据以文件形式存盘 ,并对该数据文件进行分析处理。处理结果可用图谱的形式显示、打印 ,亦可生成峰数据表或扫描数据表文件。系统结构简单 ,能充分利用仪器的机械精度 ,原仪器记录系统仍可独立工作。改造工作只需连接几对信号线便可完成 ,价格低廉 ,适用于任何旧型号的X射线衍射仪。