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Calcium titanate-CaTiO3 (perovskite) has been used in various industrial applications due to its dopant/doping mechanisms. Manipulation of defective grain boundaries in the structure of perovskite is essential to maximize mechanical properties and stability; therefore, the structure of perovskite has attracted attention, because without fully understanding the perovskite structure and diffracted planes, dopant/doping mechanisms cannot be understood. In this study, the areas and locations of atoms and diffracted planes were designed and investigated. In this research, the relationship between Young’s modulus and planar density of unit cell, super cells (2 × 2 × 2) and symmetry cells of nano CaTiO3 is investigated. Elastic constant, elastic compliance and Young’s modulus value were recorded with the ultrasonic pulse-echo technique. The results were C11 = 330.89 GPa, C12 = 93.03 GPa, C44 = 94.91 GPa and E = 153.87 GPa respectively. Young’s modulus values of CaTiO3 extracted by planar density were calculated 162.62 GPa, 151.71 GPa and 152.21 GPa for unit cell, super cells (2 × 2 × 2) and symmetry cells, respectively. Young’s modulus value extracted by planar density of symmetry cells was in good agreement with Young’s modulus value measured via ultrasonic pulse-echo.  相似文献   
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Background  

It is widely recognized and accepted that job strain adversely impacts the workforce. Individual responses to stressful situations can vary greatly and it has been shown that certain people are more likely to experience high levels of stress in their job than others. Studies highlighted that there can be age differences in job strain perception.  相似文献   
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Mg-based alloys have several suitable properties for biomaterials, but they have major problems of being less antibacterial and have a low mechanical strength. To solve these problems, a new combination of Ag/Zn/Mg was prepared in this study, where the presence of Zn and Ag can help to increase the bioactivity. The use of 5 wt.% polymers consisting of PolyCaproLactone (PCL), PolyHydroxyButyrate (PHB) and PolyVinylTriMethoxySilane (PVTMS) is also investigated. DSC, XRD, TEM, FTIR, SEM, and EDAX analysis, as well as mechanical and bioactive behavior, were investigated to characterize the prepared composites. In the comparison, the best behavior was found when PHB was used. The results show that the strength values ranged from ~201 to 261 MPa.  相似文献   
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OBJECTIVE: Fine-needle aspiration (FNA) is the procedure of choice for accurate diagnosis of infected necrosis. However, invasive procedures increase the risk of secondary pancreatic infection and the timing of FNA is still a matter for debate. Our objective was to assess the value of routine clinical tests to determine the minimal risk for infected necrosis, thereby optimizing timing and selection of patients for image-guided FNA. MATERIAL AND METHODS: This prospective, non-randomized study comprised 90 patients with acute necrotizing pancreatitis. The data of 52 patients were used for discriminant function analysis to determine the differences between patients with infected necrosis and those with sterile necrosis. Cut-off points for variables were established using receiver operating characteristic (ROC) curve analysis and logistic regression was performed to determine the risk of infected necrosis. The clinical relevance of the defined diagnostic system was prospectively tested in a further 38 consecutive patients with acute necrotizing pancreatitis (ANP). RESULTS: Discriminant function analysis showed that C-reactive protein (CRP) and white blood cell (WBC) values were significant discriminators between patients with sterile necrosis and those with infected necrosis. Cut-off values of 81 mg/l for CRP and 13 x 10(9)/l for WBC were established. The predicted risk for infected necrosis is approx. 1.4% if both tests are below the defined cut-off values. Consequently, we found FNA unnecessary in this subset of patients, unless otherwise indicated, as this invasive procedure per se carries a certain risk of bacterial contamination. CONCLUSIONS: Routine clinical tests are helpful in diagnosing the development of infected necrosis. Based on the application of classification functions, the timing and selection of patients for image-guided FNA can be optimized.  相似文献   
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INTRODUCTION: The comparison of HIV prevalence among blood donations in European countries provides an indication of the relative safety of the blood supply in different countries and over time. METHODS: Data between 1990 and 2004 on annual numbers of blood donations and HIV prevalence in blood donations were collected from national correspondents in the 52 countries of the World Health Organization European Region. Data are presented for three geographic areas: West, Centre and East. RESULTS: Since 1990, the number of blood donations has declined by 43% in the East and by 26% in the Centre, while remaining relatively stable in the West. In 2004, the number of blood donations was more than twice as high in the West in comparison with the East and the Centre. Over the same period, HIV prevalence among blood donations increased dramatically in the East, remained stable in the Centre and declined in the West. Since 2001, HIV prevalence levels of more than 10 per 100 000 donations were reported from six countries in the East (with a high of 128/100 000 in Ukraine), whereas in the rest of Europe the reported national HIV prevalence levels were lower than 10/100 000 donations. The prevalence of HIV was much lower among donations from repeat donors than from first-time donors. CONCLUSION: In some eastern European countries public health interventions, such as deferring individuals at risk of HIV infection from donating blood and constituting a pool of regular donors, are urgently needed to assure the safety of the blood supply.  相似文献   
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The purpose of this study was to develop and validate a new software, HER2-CONNECTTM, for digital image analysis of the human epidermal growth factor receptor 2 (HER2) in breast cancer specimens. The software assesses immunohistochemical (IHC) staining reactions of HER2 based on an algorithm evaluating the cell membrane connectivity. The HER2-CONNECTTM algorithm was aligned to match digital image scorings of HER2 performed by 5 experienced assessors in a training set and confirmed in a separate validation set. The training set consisted of 167 breast carcinoma tissue core images in which the assessors individually and blinded outlined regions of interest and gave their HER2 score 0/1+/2+/3+ to the specific tumor region. The validation set consisted of 86 core images where the result of the automated image analysis software was correlated to the scores provided by the 5 assessors. HER2 fluorescence in situ hybridization (FISH) was performed on all cores and used as a reference standard. The overall agreement between the image analysis software and the digital scorings of the 5 assessors was 92.1% (Cohen’s Kappa: 0.859) in the training set and 92.3% (Cohen’s Kappa: 0.864) in the validation set. The image analysis sensitivity was 99.2% and specificity 100% when correlated to FISH. In conclusion, the Visiopharm HER2 IHC algorithm HER2-CONNECTTM can discriminate between amplified and non-amplified cases with high accuracy and diminish the equivocal category and thereby provides a promising supplementary diagnostic tool to increase consistency in HER2 assessment.  相似文献   
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