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1.
目的 建立同时测定注射用胸腺法新中乙腈、二氯甲烷、醋酸乙酯、苯和苯甲醚5种有机溶剂残留量的顶空气相色谱法。方法 采用Agilent DB-624(30 m×0.53 mm×3 μm)毛细管色谱柱;火焰离子化检测器;进样口温度200℃;检测器温度250℃;载气为氮气;载气体积流量为2.0 mL·min-1;分流比为10:1;升温程序:起始温度40℃,保持6 min,以8℃·min-1的速率升温至90℃,保持2 min,再以20℃·min-1的速率升温至200℃,保持5 min;采用顶空进样方式,顶空加热箱温度80℃,样品瓶平衡时间30 min。进行系统适用性、检测限(LOD)与定量限(LOQ)、线性关系和范围、加样回收率、精密度、稳定性、耐用性考察。结果 注射用胸腺法新中5种残留溶剂在各自线性浓度范围内与峰面积线性关系良好;平均加样回收率在95.7%~106.3%;精密度、稳定性、耐用性均符合要求。5批胸腺法新中均未检出5种有机溶剂。结论 建立的顶空气相色谱法操作简单、灵敏度和准确度高、重现性和耐用性好,可用于注射用胸腺法新中5种有机溶剂残留量的测定。  相似文献   
2.
《Dental materials》2022,38(5):811-823
ObjectivesIn-vivo experimental techniques to understand the biomechanical behavior of a restored tooth, under varying oral conditions, is very limited because of the invasive nature of the study and complex tooth geometry structure. Therefore, 3D-Finite element analyses are used to understand the behavior of a restored tooth under varying oral conditions. In this study, the distribution of maximum principal stress (MaxPS) and the location of MaxPS on a restored tooth using six different commercially available dental resin composites under the influence of thermal and thermomechanical stimuli are performed.MethodsAn intact tooth was scanned using µ-CT and segmented to obtain separate geometric models of the tooth, including enamel and dentine. Then, a class II mesial-occlusal-distal (MOD) cavity was constructed for the tooth model. The restored tooth model was further meshed and imported to the commercial Finite Element (FE) software ANSYS. Thermal hot and cold stimuli at 50 °C and 2 °C, respectively, were applied on the occlusal and lingual surface of the tooth model with the tooth’s ambient temperature set at 37 °C. A uniform loading of 400 N was applied on the occlusal surface of the tooth to imitate the masticatory forces during the cyclic thermal stimuli.ResultsThe results of this study showed that the restorative materials with higher thermal conductivity showed a lower temperature gradient between the restoration and enamel, during the application of thermal stimuli, leading to a higher value of MaxPS on the restoration. Moreover, on applying thermal stimuli, the location of MaxPS at the restoration-enamel junction (REJ) changes based on the value of the coefficient of thermal expansion (CTE). The MaxPS distribution on the application of simultaneous thermal and mechanical stimuli was not only dependent on the elastic modulus of restorative materials but also their thermal properties such as the CTE and thermal conductivity. The weakest part of the restoration was at the REJ, as it experienced the peak stress level during the application of thermomechanical stimuli.SignificanceThe findings from this study suggest that restorative materials with lower values of elastic modulus, lower coefficient of thermal expansion and higher values of thermal conductivity result in lower stresses on the restoration. The outcomes from this study also suggest that the thermal and mechanical properties of a restorative material can have a considerable effect on the selection of restorative materials by dental clinicians over conventional restorative materials.  相似文献   
3.
Species identification of unknown biological samples is crucial for forensic applications, especially in cases of explosion, disaster accidents, and body mutilation after murdering, as well as poaching, illegal trade in endangered animals, and meat food fraud. In this study, we identified 60 volatile organic compounds (VOCs) in fresh skeletal muscle tissues of seven different animal species (cattle, sheep, pigs, rabbits, rats, chickens and carp) and a human dead body by headspace-gas-chromatography ion-mobility spectrometry (HS-GC-IMS), and compared their differences by retention time, drift time and molecular weight. The results showed that these VOCs formed different gallery plot fingerprints in the skeletal muscle tissues of the human dead body and seven animal species. Principal component analysis (PCA) showed significantly different fingerprints between these species, and these fingerprints maintained good stability between the species and within the same species. Some VOCs have high species specificity, while VOCs of human fresh muscle tissues from different individual sources have little difference, demonstrating that all tested muscle tissue samples could be distinguished based on different VOCs. HS-GC-IMS has proved to be a rapid, high-throughput, highly sensitive and specific species identification method, which can be used for forensic species identification in criminal cases and disaster accidents, as well as detection in the field of food safety, such as meat fraud and adulteration.  相似文献   
4.
青少年特发性脊柱侧凸发病率较高且病情复杂,对青少年身心健康可造成显著影响,但其因病因不明,临床尚未形成治疗共识。近年来基于患者医学影像进行仿真建模的有限元法生物力学分析在青少年特发性脊柱侧凸治疗及其病因研究中已经有了一系列的应用。本文即从非手术治疗、手术治疗、病因研究、现有局限等角度对有限元法生物力学分析在青少年特发性脊柱侧凸中的应用进行综述,以期为临床实践及相关研究提供参考。  相似文献   
5.
Tsukamurella species are obligate aerobic, gram-positive, weak acid-fast, nonmotile bacilli. They are found in various environments, such as soil, water, sludge, and petroleum reservoir wastewater, and belong to the order Actinomycetales. In 2016, there was a reclassification of species within the genus Tsukamurella, merging the species Tsukamurella tyrosinosolvens (T. tyrosinosolvens) and Tsukamurella carboxydivorans. Tsukamurella species are clinically considered to be a rare opportunistic pathogen, because most reported cases have been related to bacteremia and intravascular prosthetic devices and immunosuppression. To date, it has been isolated only from human specimens, and has always been associated with clinical disease; human infections are very rare. Reported infections have included pneumonia, brain abscesses, catheter-related bloodstream infections, ocular infections, bacteremia, and sepsis presenting with septic pulmonary emboli in patients who are immunocompromised. To date, there is no commercially available test for identification. On the other hand, sequence-based identification, including matrix-assisted laser desorption ionization time-of-flight mass spectrometry, is an alternative method for identifying clinical isolates that are either slow growers or difficult to identify through biochemical profiling. The golden standards for diagnosis and optimal management still remain to be determined. However, newer molecular biological techniques can provide accurate identification, and contribute to the appropriate selection of definitive therapy for infections caused by this organism. Combinations of several antimicrobial agents have been proposed for treatment, though the length of treatment for infections has yet to be determined, and should be individualized according to clinical response. Immunocompromised patients often experience severe cases due to infection, and life-threatening T. tyrosinosolvens events associated with dissemination and/or failure of source control have occurred. Favorable prognoses can be achieved through earlier identification of the cause of infection, as well as successful management, including appropriate antibiotic therapy together with source control. Further analyses of similar cases are required to establish the most adequate diagnostic methods and treatment regimens for infections.  相似文献   
6.
ObjectivesWe investigated whether nanopore 16S amplicon sequencing is capable of bacterial identification in patients with knee prosthetic joint infection (PJI), and we compared its efficacy with conventional culture studies.MethodsIn total, 36 patients who had clinical manifestation suspected of PJI were enrolled in this study. To begin, synovial fluids were aspirated from the affected knee using aseptic technique and tissues specimens were obtained during the surgery. Next, DNA was extracted from the synovial fluid or tissues, and 16S rDNA PCR was performed. In PCR positive cases, nanopore amplicon sequencing was then performed for up to 3 h. The results of amplicon sequencing were compared to those of conventional culture studies.ResultsOf the 36 patients enrolled, 22 were classified as true infections according to the MSIS criteria whereas 14 were considered uninfected. Among the 22 PJI cases, 19 cases were culture positive (CP-PJI) while three cases were culture negative (CN-PJI). In 14 of 19 (73.7 %) CP- PJI cases, 16S sequencing identified concordant bacteria with conventional culture studies with a significantly shorter turnaround time. In some cases, nanopore 16S sequencing was superior to culture studies in the species-level identification of pathogen and detection of polymicrobial infections. Altogether, in the majority of PJI candidate patients (32 of 36, 88.9 %), 16S sequencing achieved identical results to cultures studies with a significantly reduced turnaround time (100.9 ± 32.5 h vs. 10.8 ± 7.7 h, p < 0.001).ConclusionsNanopore 16S sequencing was found to be particularly useful for pathogen identification in knee PJI. Although the sensitivity was not superior to culture studies, the nanopore 16S sequencing was much faster, and species-level identification and detection of polymicrobial infections were superior to culture studies.  相似文献   
7.
把握状态是维护健康的关键。中医美容健康管理体系以状态辨识为核心,对皮肤、形体局部状态及整体健康状态进行辨识、干预、评价,从而对损美性疾病进行管理与维护。中医美容健康管理体系应重视三观并用及四态管理,即从宏观、中观、微观的三观层面采集皮肤、形体与整体状态的参数信息,整体审查、四诊合参,对皮肤、形体与整体所处的未病状态、欲病状态、已病状态和病后状态进行辨识和诊断,并运用相应的干预手段,对状态进行调整。同时,应规范中医美容健康管理服务的流程,着重解决中医美容健康管理体系构建中5个核心内容的关键问题,为求美者提供整体、动态、个性化的管理服务,对促进中医健康管理与中医美容的交叉与融合,维护人体的健康美具有重要意义。  相似文献   
8.
摘要:目的 了解不同检测方法在耐碳青霉烯肺炎克雷伯菌(carbapenem-resistant Klebsiella pneumoniae, CRKP)对多黏菌素 B体外药敏检测中的差异,为临床治疗和实验室检测提供依据。方法 选择2018-2020年宁波地区临床分离的CRKP 147株,分 别采用肉汤稀释法、E-test纸片法、仪器法(N335药敏卡)和纸片法检测其体外对多黏菌素B的敏感性,分析4种药敏检测方法所 存在的差异。结果 微量肉汤稀释法、E-test法和仪器检测CRCP对多黏菌素B MIC50分别为1、1和0.5μg/mL,MIC90分别为1、 1和0.5,累积敏感率分别为97.3%、99.3%和98%,具有较高一致性和敏感性;仪器法检测CRKP对多黏菌素B的平均MIC值为 (0.82±0.16)μg/mL,明显低于标准方法的(1.39±0.27)μg/mL,差异有统计学意义(P<0.01);E-test法和仪器法的基本一致率(EA) 为92.5%和94.6%,标准符合(CA)分别为97.3%和98.6%,严重错误(VME)分别为2.7%和1.4%;重大错误(ME)和小错误(mE)均为 0;纸片法KB值与肉汤稀释法MIC值之间方差分析P>0.05,故提示KB值与MIC值不具有线性关系。结论 4种方法检测CRKP 对多黏菌素B体外具有较高敏感性;仪器法和E-test法对于多黏菌素B的敏感性检测与微量肉汤稀释法高度一致,但其中仪器法 N335药敏卡检测MIC有所降低,建议标准方法复核。  相似文献   
9.
目的:将彩色多普勒超声检查对肉芽肿性乳腺炎、乳腺癌的鉴别诊断价值进行分析。方法:对本院2018年3月~2019年3月收治的60例肉芽肿性乳腺炎患者与60例乳腺癌患者的彩色多普勒超声诊断进行回顾性分析,并将其超声表现进行对比与研究。结果:在60例肉芽肿性乳腺炎患者的超声结果中发现,52例患者为单发性肉芽肿性乳腺炎,38例患者病灶部位位于左侧乳腺,14例患者病灶部位位于右侧乳腺,8例患者为多发性肉芽肿性乳腺炎。乳腺腺体实性肿块37例,呈假肾征,且腺体可见稍强回声,60例乳腺癌患者超声表现均为实性肿块,且边缘不规则,腺体内部可见不均质低回声,边缘可见形态不规则,厚度不均晕环,肉芽肿性乳腺炎患者的病灶肿块范围明显大于乳腺癌患者(P<0.05)。肉芽肿性乳腺炎以及乳腺癌患者的超声声像图比较,差别较大(P<0.05)。结论:肉芽肿性乳腺炎与乳腺癌的彩色多普勒超声表现不同,可作为对肉芽肿性乳腺炎与乳腺癌鉴别诊断的首选检查方式。  相似文献   
10.
The simulation of rarefied gas flows through complex porous media is challenging due to the tortuous flow pathways inherent to such structures. The Lattice Boltzmann method (LBM) has been identified as a promising avenue to solve flows through complex geometries due to the simplicity of its scheme and its high parallel computational efficiency. It has been proposed to model the stress-strain relationship with the extended Navier-Stokes equations rather than attempting to directly solve the Boltzmann equation. However, a regularization technique is required to filter out non-resolved higher-order components with a low-order velocity scheme. Although slip boundary conditions (BCs) have been proposed for the non-regularized multiple relaxation time LBM (MRT-LBM) for planar geometries, previous slip BCs have never been verified extensively with the regularization technique. In this work, following an extensive literature review on the imposition of slip BCs for rarefied flows with the LBM, it is proven that earlier values for kinetic parameters developed to impose slip BCs are inaccurate for the regularized MRT-LBM and differ between the D2Q9 and D3Q15 schemes. The error was eliminated for planar flows and good agreement between analytical solutions for arrays of cylinders and spheres was found with a wide range of Knudsen numbers.  相似文献   
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