85 research outputs found

    Imaging Software Programs for Reliable Mathematical Measurements in Orthodontics

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    Aim: To evaluate the reliability of linear and angular measurements taken using different software programs in orthodontics. Materials and Methods: A sample of four software programs from different manufacturers, namely MicroDicom viewer, Photoshop® CS3, AutoCAD®, and Image-Pro®, were used for measuring the geometric features of four types of miniscrews from different manufacturers. Each miniscrew type presented a group: Group I, Tomas® (Dentaurum, Ispringen, Germany); Group II, HUBIT® (HUBIT, Gyeonggi-do, Korea); Group III, AbsoAnchor® (Dentos, Daegu, Korea); and Group IV, Creative (Creative, Zhejiang, China). Measurements of apical face angle, thread angle, lead angle, flank, pitch depth, and width were taken on 45 × magnification scanning electron microscope images of the shafts of the miniscrews. One assessor measured the seven geometric features for the four types of miniscrews using the four software programs twice in two sessions separated by a three week interval. Results: Pairwise comparisons, for each of the four miniscrew groups, showed that the only common result observed was the significant difference (p < 0.001) between measurements of flank taken by the four software programs. When measurements of the four types of miniscrews were pooled into one group, a high degree of intra-rater reliability (ICC range from 0.9 to 1.0) for all the seven geometric features was found with all the four software programs. The paired t-test showed insignificant difference (at p ≤ 0.05) between the first and second measurements, except for a few measurements including pitch width measured by Image-Pro® (p = 0.012), MicroDicom (p = 0.023), and Photoshop® (p = 0.001). Conclusions: Results did not give absolute superiority to one software program over the others and suggested an assessor effect. Assessor estimates could have been affected, among other factors, by the design of the miniscrews and the technical features of the software programs

    Improving the classification of multiple disorders with problem decomposition

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    AbstractDifferential diagnosis of multiple disorders is a challenging problem in clinical medicine. According to the divide-and-conquer principle, this problem can be handled more effectively through decomposing it into a number of simpler sub-problems, each solved separately. We demonstrate the advantages of this approach using abductive network classifiers on the 6-class standard dermatology dataset. Three problem decomposition scenarios are investigated, including class decomposition and two hierarchical approaches based on clinical practice and class separability properties. Two-stage classification schemes based on hierarchical decomposition boost the classification accuracy from 91% for the single-classifier monolithic approach to 99%, matching the theoretical upper limit reported in the literature for the accuracy of classifying the dataset. Such models are also simpler, achieving up to 47% reduction in the number of input variables required, thus reducing the cost and improving the convenience of performing the medical diagnostic tests required. Automatic selection of only relevant inputs by the simpler abductive network models synthesized provides greater insight into the diagnosis problem and the diagnostic value of various disease markers. The problem decomposition approach helps plan more efficient diagnostic tests and provides improved support for the decision-making process. Findings are compared with established guidelines of clinical practice, results of data analysis, and outcomes of previous informatics-based studies on the dataset

    Modeling of Nitrogen in River Water Using a Detailed and a Simplified Model

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    To model catchment surface water quantity and quality, different model types are available. They vary from detailed physically based models to simplified conceptual and empirical models. The most appropriate model type for a certain application depends on the project objectives and the data availability. The detailed models are very useful for short-term simulations of representative events. They cannot be used for long-term statistical information or as a management tool. For those purposes, more simplified (conceptual or meta-) models must be used. In this study, nitrogen dynamics are modeled in a river in Flanders. Nitrogen sources from agricultural leaching and domestic point sources are considered. Based on this input, concentrations of ammonium (NH4-N) and nitrate (NO3-N) in the river water are modeled in MIKE 11 by taking into consideration advection and dispersion and the most important biological and chemical processes. Model calibration was done on the basis of available measured water quality data. To this detailed model, a more simplified model was calibrated with the objective to more easily yield long-term simulation results that can be used in a statistical analysis. The results show that the conceptual simplified model is 1800 times faster than the MIKE 11 model. Moreover the two models have almost the same accuracy. The detailed models are recommended for short-term simulations unless there are enough data for model input and model parameters. The conceptual simplified model is recommended for long-term simulations

    Numerical Analysis of the Transport and Fate of Nitrate in the Soil and Nitrate Leaching to Drains

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    In this study, the transport and fate of nitrate within the soil profile and nitrate leaching to drains were analyzed by comparing historic field data with the simulation results of the DRAINMOD model. The nitrogen version of DRAINMOD was used to simulate the performance of the nitrogen transport and transformation of the Hooibeekhoeve experiment, situated in the sandy region of the Kempen (Belgium) and conducted for a 30-year (1969–1998) period. In the analysis, a continuous cropping with maize was assumed. Comparisons between experimentally measured and simulated state variables indicate that the nitrate concentrations in the soil and nitrate leaching to drains are controlled by the fertilizer practice, the initial conditions, and the rainfall depth and distribution. Furthermore, the study reveals that the model used gives a fair description of the nitrogen dynamics in the soil and subsurface drainage at field scale. From the comparative analysis between experimental data and simulation results it can also be concluded that the model after calibration is a useful tool to optimize as a function of the combination “climate-crop-soil-bottom boundary condition” the nitrogen application strategy resulting in an acceptable level of nitrate leaching for the environment

    Synthesis of New Coumarin Derivatives Used as Nitrification Inhibitors to Mitigation of Nitrous Oxide Emission from Agricultural Soil.

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    Nitrous oxide (N2O) is one of the major greenhouse gases "GHG” the main source of N2O emission is synthetic mineral nitrogen fertilizers. The conversion values according to the global warming potential for N2O are 298 times as CO2 per molecule. The main objective of this work is to mitigate GHG emission from N2O by create synthesis new nitrification inhibitors.  Coumarine derivatives were synthesized (1-4), and prove the structures by spectral data, the compounds (1) and (4) were applied as nitrification inhibitors to mitigation of nitrous oxide. The results indicated that, the presence of each of the two tested inhibitors (1, 4) reduced the N2O emission from urea-treated soils by 72% and 49%, respectively, in inhibiting nitrification during the 28-day incubation period. Key words: Nitrous oxide emissions, Mitigation, Agricultural soil, Nitrification, Coumarin derivatives

    Hemodynamic changes and stress response during BIS-guided TCI anesthesia with propofol-fentanyl in laparoscopic versus open cholecystectomy

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    AbstractBackgroundLaparoscopic surgery produces measurable effects on cardio-circulatory, respiratory and metabolic systems. Total intravenous anesthesia with propofol using target-controlled infusion technique guided by Bispectral Index monitoring ensures an optimum level of anesthesia. This study was designed to evaluate the hemodynamic changes with the use of BIS-guided TCI with propofol-fentanyl during either laparoscopic or open cholecystectomy.MethodsTwenty-four ASA class I-II patients, scheduled for cholecystectomy under general anesthesia using BIS-guided TIVA with propofol-fentanyl delivered by TCI pump, were divided surgically into laparoscopic surgery group (LS group, n=12) and open surgery group (OS group, n=12). Hemodynamic data as well as stress hormones were measured at various time intervals.ResultsWithin LS, there was rise of both cardiac output after abdominal insufflation (p<0.05) and stroke volume after end of surgery (p<0.05). Blood pressure decreased in the two groups after insufflation in LS and skin incision in OS (p<0.01) as well as after 15min (p<0.05 & p<0.01 respectively). LS showed decrease in SVR starting from insufflation till end of surgery, while OS showed this decrease only with skin incision. Heart rate decreased 15min after surgical incision till end of surgery in OS while LS showed decrease only after end of surgery. Only in OS, norepinephrine & epinephrine levels showed significant rises throughout the period of study (p<0.001). Cortisol level was elevated after 30min in LS while OS showed a rise after the end of surgery (p<0.001). ACTH levels increased in OS (p<0.001). There was positive correlation between CO and epinephrine, norepinephrine and ACTH in OS.ConclusionBIS-guided TCI anesthesia with propofol-fentanyl offers a good and safe anesthesia technique for patients undergoing either laparoscopic or open cholecystectomy. The hemodynamic stability guided by esophageal Doppler monitor makes it a very appealing choice

    CXCR 3 expression on CD4+T cells and in renal tissue of pediatric systemic lupus erythematosus patients

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    Background: Pediatric systemic lupus erythematosus (pSLE) accounts for about 20% of all cases of Systemic Lupus Erythematosus (SLE), with nephritis occurring in approximately 50% of the patients. Objective: to evaluate the expression of CXCR3 in the kidneys and on CD4+ T cells in pSLE. Methods: This study was conducted on 45 patients with pSLE following up at the Allergy and Immunology Clinic, Children’s Hospital, Ain Shams University and 45 age and sex matched healthy children as a control group. Medical history, clinical examination and routine laboratory investigations for assessment of disease activity were done for all patients, the frequency of CXCR3, CD4+ T cells was determined in all patients and controls. Twenty-five Paraffin blocks of patients with lupus nephritis (LN) (available at the time of the study) underwent immunohistochemistry staining for the frequencies of Chemokine C receptor (CXCR3). Results: The absolute level and percentage of serum CD4+CXCR3+ were significantly lower among our patients as compared to healthy controls. A significant direct correlation was found between serum CD4+CXCR3+ and both the lymphocytic count and quantitative Systemic Lupus erythematosus disease activity index (SLEDAI), as well as a significant inverse correlation between it and 24 hours urinary proteins. Variable degrees of CXCR3expression seemed to have no impact on laboratory tests, British Isles Lupus Assessment Group (BILAG) score and cumulative doses of Immunosuppressives. Conclusion: Serum CD4+CXCR3+ and not renal CXCR3 may be a potential marker of LN activity

    Membrane endothelial protein C receptor expression in renal tissue of pediatric lupus nephritis patients

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    Background: Lupus nephritis (LN) is more common and more severe is pediatric systemic lupus erythematosus (pSLE). Endothelial protein C receptor (EPCR) is an inducer of anti-apoptotic pathways in endothelial cells. Recent studies have taken elevated anti-injury biomarkers as EPCR into consideration regarding their roles to antagonize LN.Objectives: to evaluate the membrane expression of endothelial protein C receptor (mEPCR) in the renal microvasculature in pediatric patients with LN.Methods: This study was conducted on 25 patients with pSLE following up at the Allergy and Immunology Clinic, Children’s Hospital, Ain Shams University. The 25 patients have LN proved by a previous renal biopsy. Medical history, clinical examination and routine laboratory investigations for assessment of disease activity were done for all patients. Paraffin blocks of patients’ renal biopsies were subjected to immunohistochemistry staining for the frequency of mEPCR.Results: mEPCR was mainly expressed in the endothelium of the peritubular capillaries. Our results showed that an equal number of patients had nil and mild marker expression (8 patients each, 32%) while 9 patients (36%) showed moderate/strong marker expression. We found that 9 out of 10 (90%) of patients with class II had nil/mild marker expression, 5 patients out of 9 (55.5%) with class III had mild/moderate marker expression, while 5 patients 0ut of 6 (83.3%) with class IV and V had moderate/strong marker expression. We only found a significant statistical difference between the different degrees of mEPCR expression regarding 24 hours urinary proteins. No statistical significance was found between the different degrees of mEPCR expression and different immuno-suppressive therapy dose/kg or renal outcome using the renal British Isles Lupus Assessment Group (BILAG) score; in spite that most of the patients who got improved had nil/mild marker expression.Conclusion: mEPCR -bearing a statistically significant difference in relation to different LN classes- showed more expression in the more aggressive classes; a finding which might suggest a contribution of the endothelium of the renal parenchyma to the pathophysiology of more progressive LN. Hence the tissue marker might emerge as a potential new therapeutic target in the search for more selective treatment for SLE.Keywords: p SLE, mEPCR, renal biopsy, immunohistochemistry, BILAG, lupus nephriti

    Improving the Classification of Multiple Disorders with Problem Decomposition

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    Abstract Differential diagnosis of multiple disorders is a challenging problem in clinical medicine. According to the divide-and-conquer principle, this problem can be handled more effectively through decomposing it into a number of simpler sub-problems, each solved separately. We demonstrate the advantages of this approach using abductive network classifiers on the 6-class standard dermatology dataset. Three problem decomposition scenarios are investigated, including class decomposition and two hierarchical approaches based on clinical practice and class separability properties. Two-stage classification schemes based on hierarchical decomposition boost the classification accuracy from 91% for the single-classifier monolithic approach to 99%, matching the theoretical upper limit reported in the literature for the accuracy of classifying the dataset. Such models are also simpler, achieving up to 47% reduction in the number of input variables required, thus reducing the cost and improving the convenience of performing the medical diagnostic tests required. Automatic selection of only relevant inputs by the simpler abductive network models synthesized provides greater insight into the diagnosis problem and the diagnostic value of various disease markers. The problem decomposition approach helps plan more efficient diagnostic tests and provides improved support for the decision making process. Findings are compared with established guidelines of clinical practice, results of data analysis, and outcomes of previous informatics-based studies on the dataset. Keywords: Classifiers, Abductive Networks, Neural Networks, Problem Decomposition, Divide and Conquer, Classification Accuracy, Data Reduction, Modular Networks, Medical Diagnosis, Multiple Disorders, Dermatology.
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