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.

基于多动物模型药效评价体系研究羚羊感冒口服液儿童用药剂量

目的确定羚羊感冒口服液儿童用药的有效性和最佳剂量范围,增加其儿童用法用量,为儿童临床应用提供参考。方法基于多动物模型药效评价体系,采用反映主要功能主治的5种相应幼龄动物模型,包括甲型H1N1流感病毒感染致小鼠肺炎模型;冰醋酸致小鼠腹腔毛细血管通透性增加急性炎症模型;氨水雾化致小鼠咳嗽模型;冰醋酸致小鼠疼痛模型;脂多糖(LPS)致家兔发热模型,分别观察羚羊感冒口服液的人用剂量(儿童)0.1、0.2、0.4、0.6、0.8、1.0mL·kg^(-1)·d^(-1)6个剂量组抗病毒、抗炎、止咳、镇痛及解热的有效性,按体表面积换算公式换算为动物用量:小鼠用量分别为1、2、4、6、8、10 mL·kg^(-1)·d^(-1);家兔用量分别为0.3、0.6、1.2、1.8、2.4、3.0 mL·kg^(-1)·d^(-1)。最终根据结果确定儿童最佳剂量范围。结果羚羊感冒口服液在所试剂量范围内均可在一定程度上降低小鼠肺指数、抑制小鼠毛细血管通透性、减少小鼠咳嗽次数及扭体次数、降低家兔体温,其中发挥稳定药效的剂量范围分别为4.0~8.0 mL·kg^(-1)·d^(-1)和1.2~2.4m L·kg^(-1)·d^(-1),相当于人用剂量0.4~0.8 m L·kg^(-1)·d^(-1)。结论羚羊感冒口服液在0.4~0.8 mL·kg^(-1)·d^(-1)剂量范围内产生稳定有效的抗病毒、抗炎、止咳、镇痛及解热作用,换算成不同年龄小儿临床推荐用量为1~3岁:每次5 mL、每日1~2次;4~6岁:每次5 mL、每日1~3次;7~12岁:每次5 mL、每日2~4次。

羚羊感冒口服液多重药理作用研究

目的在动物水平对羚羊感冒口服液多重药理作用进行评价,为其临床应用提供理论依据和数据支持。方法依据羚羊感冒口服液的功能主治及临床适应证,建立6种动物模型:流感病毒FM1株及肺炎链球菌感染小鼠致肺炎模型,冰醋酸致小鼠腹腔毛细血管通透性模型及扭体模型,氨水致小鼠咳嗽模型及小鼠气管酚红排泌模型。通过观察肺指数、肺指数抑制率、伊文思蓝OD值、扭体次数,咳嗽次数及酚红排泌量等药效指标,评价羚羊感冒口服液的抗病毒、抗菌、抗炎、止痛、止咳、化痰作用。结果羚羊感冒口服液20 mL·kg^(-1)·d^(-1)剂量组可显著抑制流感病毒FM1引起的肺指数增高,明显增加小鼠气管酚红排泌量;肺炎链球菌感染小鼠的肺指数升高及腹腔毛细血管通透性增强,羚羊感冒口服液20、15、10 mL·kg^(-1)·d^(-1)3个剂量组对咳嗽有明显抑制作用,可显著减少氨水引起的小鼠咳嗽次数,延长咳嗽潜伏期;20、15 mL·kg^(-1)·d^(-1)2个剂量组均可显著减少醋酸致小鼠疼痛的扭体次数。结论不同剂量组羚羊感冒口服液作用程度不同且具有多重药理作用,包括抗病毒、抗菌、抗炎、止痛、止咳、化痰作用等。

Phase behavior of gas condensate in porous media using real-time computed tomography scanning

The phase behavior of gas condensate in reservoir formations differs from that in pressure-volume-temperature(PVT)cells because it is influenced by porous media in the reservoir formations.Sandstone was used as a sample to investigate the influence of porous media on the phase behavior of the gas condensate.The pore structure was first analyzed using computed tomography(CT)scanning,digital core technology,and a pore network model.The sandstone core sample was then saturated with gas condensate for the pressure depletion experiment.After each pressure-depletion state was stable,realtime CT scanning was performed on the sample.The scanning results of the sample were reconstructed into three-dimensional grayscale images,and the gas condensate and condensate liquid were segmented based on gray value discrepancy to dynamically characterize the phase behavior of the gas condensate in porous media.Pore network models of the condensate liquid ganglia under different pressures were built to calculate the characteristic parameters,including the average radius,coordination number,and tortuosity,and to analyze the changing mechanism caused by the phase behavior change of the gas condensate.Four types of condensate liquid(clustered,branched,membranous,and droplet ganglia)were then classified by shape factor and Euler number to investigate their morphological changes dynamically and elaborately.The results show that the dew point pressure of the gas condensate in porous media is 12.7 MPa,which is 0.7 MPa higher than 12.0 MPa in PVT cells.The average radius,volume,and coordination number of the condensate liquid ganglia increased when the system pressure was between the dew point pressure(12.7 MPa)and the pressure for the maximum liquid dropout,Pmax(10.0 MPa),and decreased when it was below Pmax.The volume proportion of clustered ganglia was the highest,followed by branched,membranous,and droplet ganglia.This study provides crucial experimental evidence for the phase behavior changing process of gas condensate in porous media during the depletion production of gas condensate reservoirs.

In-situ Micro-CT analysis of deformation behavior in sandwich-structured meta-stable beta Ti−35Nb alloy

Beta Ti−35Nb sandwich-structured composites with various reinforcing layers were designed and produced using additive manufacturing(AM)to achieve a balance between light weight and high strength.The impact of reinforcing layers on the compressive deformation behavior of porous composites was investigated through micro-computed tomography(Micro-CT)and finite element method(FEM)analyses.The results indicate that the addition of reinforcement layers to sandwich structures can significantly enhance the compressive yield strength and energy absorption capacity of porous metal structures;Micro-CT in-situ observation shows that the strain of the porous structure without the reinforcing layer is concentrated in the middle region,while the strain of the porous structure with the reinforcing layer is uniformly distributed;FEM analysis reveals that the reinforcing layers can alter stress distribution and reduce stress concentration,thereby promoting uniform deformation of the porous structure.The addition of reinforcing layer increases the compressive yield strength of sandwich-structured composite materials by 124%under the condition of limited reduction of porosity,and the yield strength increases from 4.6 to 10.3 MPa.

Low-fat microwaved peanut snacks production:Effect of defatting treatment on structural characteristics,texture,color,and nutrition

This study develops low-fat microwaved peanut snacks(LMPS)using partially defatted peanuts(PDP)with different defatting ratios,catering to people’s pursuit of healthy,low-fat cuisine.The effects of defatting treatment on the structural characteristics,texture,color,and nutrient composition of LMPS were comprehensively explored.The structural characteristics of LMPS were characterized using X-ray micro-computed tomography(Micro-CT)and scanning electron microscope(SEM).The results demonstrated that the porosity,pore number,pore volume,brightness,brittleness,protein content,and total sugar content of LMPS all significantly increased(P<0.05)with the increase in the defatting ratio.At the micro level,porous structure,cell wall rupture,and loss of intracellular material could be observed in LMPS after defatting treatments.LMPS made from PDP with a defatting ratio of 64.44%had the highest internal pore structural parameters(porosity 59%,pore number 85.3×10^(5),pore volume 68.23 mm3),the brightest color(L^(*) 78.39±0.39),the best brittleness(3.64±0.21)mm^(–1)),and the best nutrition(high protein content,(34.02±0.38)%;high total sugar content,(17.45±0.59)%;low-fat content,(27.58±0.85)%).The study provides a theoretical basis for the quality improvement of LMPS.

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.

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.

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.

融合可拓语义与模糊评价的陵阳公样设计研究

目的针对运用唐朝传统服饰纹样进行文化产品创新设计的过程中,设计者难以客观、有效地对其源文化实现表征与转化,导致所设计的产品脱离纹样原本蕴含的语义内涵与时代特征的问题,提出一种可拓语义与模糊评价相融合的传统纹样创意产品设计方法。方法以陵阳公样为例,在前期策划阶段,通过梳理陵阳公样的源文化,以可拓原理对其语义进行分析,将优选得到的特征词汇进行综合图解语义评估,结合可拓变换重构理论构建图解语义集;在后期评估阶段,可视化形态意象特征并应用于文化创意产品设计中,融合用户需求进行设计方案的满意度评价。结论融合可拓语义与模糊评价的方法具有一定的可行性与合理性,可以为传统纹样的创新转化及应用提供方法支持。

羚羊清肺丸HPLC指纹图谱建立及6种成分测定

目的建立羚羊清肺丸HPLC指纹图谱,并测定黄芩苷、黄芩素、汉黄芩苷、汉黄芩素、异绿原酸A、丹皮酚的含量。方法该药物70%甲醇提取液的分析采用Diamonsil C 18色谱柱(250 mm×4.6 mm,5μm);流动相水(含0.1%甲酸)-乙腈(含25%甲醇),梯度洗脱;体积流量1.0 mL/min;柱温30℃;检测波长260 nm。聚类分析、主成分分析、正交偏最小二乘判别分析进行化学模式识别。结果22批样品指纹图谱中有30个共有峰,相似度均大于0.970,归属于11种药材,指认出14个。各批样品聚为2类,组间差异化合物有11个。6种成分在各自范围内线性关系良好(r≥0.9994),平均加样回收率96.9%~102.7%,RSD 1.8%~3.7%。结论该方法简便,重复性好,可用于羚羊清肺丸的质量控制。

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.

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.

日本正仓院藏紫地凤形锦御轼纹样考——兼论“御轼”的用法

日本正仓院藏紫地凤形锦御轼表面织锦花纹以凤凰图案为主,四周为唐草花纹,主纹间配有菱形花草副纹。通过与甘肃敦煌、青海都兰和甘肃武威发现的相似纹样锦残片,以及与石窟、墓葬凤纹的比较,表明正仓院凤形锦完全符合唐朝盛行的“陵阳公样”的纹样特征,堪称“陵阳公样”的典型织锦。

安徽陵阳镇“文化基因”的提炼与创新策略研究

安徽陵阳镇依托自身的天然资源与历史人文,成功跻身于中国历史文化名镇行列。古镇历经百余年的孕育、生发和几次高峰的渐变后,臻于成熟。但在当前文化转型的语境中,古镇也面临着同质化的严峻挑战。依托“文化基因”的相关视角,以陵阳古镇为案例,通过文化基因的识别与甄选,从整体与动态思维原则入手,深层次发掘古镇的地域特色,并在此基础上提出相关的改造模式与更新策略,最终实现古典与当代的传承再生,达到可持续发展的目的。

羚羊铁矿石工艺矿物学

通过MLA自动检测技术、XRD等手段,对吉林省羚羊铁矿石进行了详细的工艺矿物学研究.查明了该铁矿石的化学组成、矿物组成、粒度组成及嵌布特征.结果表明:铁矿石中的铁主要赋存于磁铁矿和菱铁矿之中,少量的铁存在于鲕绿泥石和磁绿泥石等铝硅酸盐矿物之中.羚羊铁矿石矿物组成非常复杂、嵌布粒度很细、铁矿物与脉石紧密共生,且脉石矿物易泥化,属于难选铁矿石.该研究结果可作为此铁矿资源合理开发利用的参考依据.