407 research outputs found
Commercial wind turbines modeling using single and composite cumulative probability density functions
As wind turbines more widely used with newer manufactured types and larger electrical power scales, a brief mathematical modelling for these wind turbines operating power curves is needed for optimal site matching selections. In this paper, 24 commercial wind turbines with different ratings and different manufactures are modelled using single cumulative probability density functions modelling equations. A new mean of a composite cumulative probability density function is used for better modelling accuracy. Invasive weed optimization algorithm is used to estimate different models designing parameters. The best cumulative density function model for each wind turbine is reached through comparing the RMSE of each model. Results showed that Weibull-Gamma composite is the best modelling technique for 37.5% of the reached results
Evolution of second trimester low implanted placenta to previa at term: a prospective cohort study
Background: The objective of this study is to identify the percentage of low implanted placenta (LIP) at second trimester of pregnancy and identify the risk factors of its persistence to placenta previa (PP) at term.Methods: Through a registered prospective cohort study conducted at tertiary hospital in Upper Egypt, authors screened all pregnant ladies comes to present facility for antenatal second trimester USG between 18-24 weeks gestation. All participants interviewed for detailed risk factors of placenta previa. Those diagnosed to have a LIP (â€1.5 cm from the internal os) had had TVS to confirm the exact distance between the lower edge of the placenta and the internal os. Serial USG had been done every 4 weeks up to delivery to measure the same distance. The primary outcome was the percentage of LIP at 18-24 weeks. Logistic regression analysis was performed to predict the risk factors for PP at term.Results: Through screening of 1000 pregnant lady, LIP had been identified in (52 cases) 5.2% of pregnant women between 18-24 weeks. This percentage dropped gradually to reach 1.3% at 36 weeks of gestation and at time of delivery. The logistic regression analysis demonstrated that the distance between the internal os and the lower edge of the placenta between 18-24 weeks was the single significant variable associated with PP at term (p<0.001, odds ratio 0.319, 95% CI 0.20-0.50). However, excluding the distance from the regression model demonstrated other risk factors as previous miscarriage, previous cesarean section (CS), and history of multiple pregnancies and history of previous PP.Conclusions: About 5.0% of pregnant women have LIP at the second trimester of pregnancy (18-24 weeks) and only 25.0 % of them remain placenta previa at term. A cut-off value of 10 mm between the internal os and the lower edge of the placenta is the most important predictor of development of PP
Postfault operation of five-phase induction machine with minimum total losses under aingle open-phase fault
Five-phase induction machines (FPIM) have attracted notable interest in safety critical applications as well as wind energy generation systems. This is largely due to their additional degrees of freedom that retain the machine starting/running steadily under fault conditions. In the available literature, postfault operation of multiphase machines is typically implemented using two techniques: minimum losses (ML) or maximum torque per ampere (MT) strategies. The optimization embedded into the control strategy, however, mostly addresses minimization of the stator copper loss, while the effect of the rotor loss and core loss are discarded in the optimal current calculation. This paper revisits postfault operation of the FPIM under single open phase fault (1OPF) by including the effect of both rotor loss and core loss on the machine's optimal current calculation over the full achievable loading range. The proposed searching algorithm, which combines the advantages of both MT and ML techniques, attempts to minimize the total machine losses induced by the current components of both the fundamental \alpha \beta and the secondary xy subspaces. The theoretical findings have been experimentally validated using a 1.5Hp five-phase prototype system
High Performance Liquid Chromatographic Assay for the Simultaneous Determination of Posaconazole and Vincristine in Rat Plasma
Purpose. Developing a validated HPLC-DAD method for simultaneous determination of posaconazole (PSZ) and vincristine (VCR) in rat plasma. Methods. PSZ, VCR, and itraconazole (ITZ) were extracted from 200âÎŒL plasma using diethyl ether in the presence of 0.1âM sodium hydroxide solution. The organic layer was evaporated in vacuo and dried residue was reconstituted and injected through HC-C18 (4.6 Ă 250âmm, 5âÎŒm) column. In the mobile phase, acetonitrile and 0.015âM potassium dihydrogen orthophosphate (30â:â70 to 80â:â20, linear gradient over 7 minutes) pumped at 1.5âmL/min. VCR and PSZ were measured at 220 and 262ânm, respectively. Two Sprague Dawley rats were orally dosed PSZ followed by iv dosing of VCR and serial blood sampling was performed. Results. VCR, PSZ, and ITZ were successfully separated within 11âmin. Calibration curves were linear over the range of 50â5000âng/mL for both drugs. The CV% and % error of the mean were â€18% and limit of quantitation was 50âng/mL for both drugs. Rat plasma concentrations of PSZ and VCR were simultaneously measured up to 72âh and their calculated pharmacokinetics parameters were comparable to the literature. Conclusion. The assay was validated as per ICH guidelines and is appropriate for pharmacokinetics drug-drug interaction studies
Genetic Diversity and Population Structure of F3:6 Nebraska Winter Wheat Genotypes Using Genotyping-By-Sequencing
The availability of information on the genetic diversity and population structure in wheat (Triticum aestivum L.) breeding lines will help wheat breeders to better use their genetic resources and manage genetic variation in their breeding program. The recent advances in sequencing technology provide the opportunity to identify tens or hundreds of thousands of single nucleotide polymorphism (SNPs) in large genome species (e.g., wheat). These SNPs can be utilized for understanding genetic diversity and performing genome wide association studies (GWAS) for complex traits. In this study, the genetic diversity and population structure were investigated in a set of 230 genotypes (F3:6) derived from various crosses as a prerequisite for GWAS and genomic selection. Genotyping-by-sequencing provided 25,566 high-quality SNPs. The polymorphism information content (PIC) across chromosomes ranged from 0.09 to 0.37 with an average of 0.23. The distribution of SNPs markers on the 21 chromosomes ranged from 319 on chromosome 3D to 2,370 on chromosome 3B. The analysis of population structure revealed three subpopulations (G1, G2, and G3). Analysis of molecular variance identified 8% variance among and 92% within subpopulations. Of the three subpopulations, G2 had the highest level of genetic diversity based on three genetic diversity indices: Shannonâs information index (I) = 0.494, diversity index (h) = 0.328 and unbiased diversity index (uh) = 0.331, while G3 had lowest level of genetic diversity (I = 0.348, h = 0.226 and uh = 0.236). This high genetic diversity identified among the subpopulations can be used to develop new wheat cultivars
GWAS revealed effect of genotype Ă environment interactions for grain yield of Nebraska winter wheat
Background: Improving grain yield in cereals especially in wheat is a main objective for plant breeders. One of the main constrains for improving this trait is the G Ă E interaction (GEI) which affects the performance of wheat genotypes in different environments. Selecting high yielding genotypes that can be used for a target set of environments is needed. Phenotypic selection can be misleading due to the environmental conditions. Incorporating information from phenotypic and genomic analyses can be useful in selecting the higher yielding genotypes for a group of environments. Results: A set of 270 F3:6 wheat genotypes in the Nebraska winter wheat breeding program was tested for grain yield in nine environments. High genetic variation for grain yield was found among the genotypes. G Ă E interaction was also highly significant. The highest yielding genotype differed in each environment. The correlation for grain yield among the nine environments was low (0 to 0.43). Genome-wide association study revealed 70 marker traits association (MTAs) associated with increased grain yield. The analysis of linkage disequilibrium revealed 16 genomic regions with a highly significant linkage disequilibrium (LD). The candidate parentsâ genotypes for improving grain yield in a group of environments were selected based on three criteria; number of alleles associated with increased grain yield in each selected genotype, genetic distance among the selected genotypes, and number of different alleles between each two selected parents. Conclusion: Although G Ă E interaction was present, the advances in DNA technology provided very useful tools and analyzes. Such features helped to genetically select the highest yielding genotypes that can be used to cross grain production in a group of environments
Effect of Intravenous Dexmedetomidine Infusion on Interleukin-6 (IL-6) and Plasma Cortisol in Open Heart Surgery
Aim of the work: to evaluate the effect of intravenous dexmedetomidine infusion on patients
undergoing open heart surgery regarding stress response markers as plasma interleukin-6 and
plasma cortisol.
Patents and Methods: Fifty consecutive patients aged 18-70years, scheduled for elective open
heart surgery using CPB technique were enrolled in this study at the Cardiothoracic Surgery Unit,
Luxor international hospital, from July 2018 to May 2019. Patients randomly assigned using closed
envelope technique into two equal groups according to the drug infused intraoperatively: 1st group (25 patients):- Dexmedetomidine group (Group D); received loading dose of intravenous
dexmedetomidine infusion of 1 ÎŒg/kg IV dissolved in 20ml normal saline over 10 minutes followed
by maintenance dose of 0.5 ÎŒg/kg/hr. till the end of surgery where 0.5 ÎŒg /kg/h was calculated for
each patient and dissolved in 12.5 ml normal saline 2nd group ( 25 patients):- placebo group (Group P); receive 20ml intravenous infusion of normal saline 0.9 % over 10 minutes followed by
continuous infusion of 12.5 ml of normal saline till the end of surgery.
Results: Our study revealed that HR and MAP wasnât significantly different between the two
groups at the baseline, but significantly lowered in Dex. group after induction, during CPB, post
CPB, and postoperative.Dexometomedine suppress the intraoperative and postoperative rise of IL-6
which was significantly higher in placebo group relative to Dex. group. Also dexometomedine has
effect on stress hormone as serum cortisol and serum glucose decease in Dex. group relative to
placebo group. None of studied cases revealed bradycardia or hypotention and there are no
significant difference between groups regarding side effect drowsiness, nausea and vomiting
Conclusion: This study demonstrated that the continuous administration of dexmedetomidine
during open heart surgery with CPB suppressed intraoperative and post-operative cytokine
secretion, and improved post-operative inflammatory response indices in the present study. Also it
stabilize blood pressure and heart rate and blunt cardiovascular response to CPB. These results
could be attributed to the anti-inflammatory effects of dexmedetomidine
Methylene tetrahydrofolate reductase, transforming growth factor-ÎČ1 and lymphotoxin-α genes polymorphisms and susceptibility to rheumatoid arthritis
AbstractBackgroundRheumatoid arthritis is a widely prevalent autoimmune disorder with suggested genetic predisposition.ObjectivesThe aim of this study is to detect the pattern of genetic polymorphism of methylene tetrahydrofolate reductase (MTHFR C677 T and A1298 C), transforming growth factor-ÎČ1 (TGF-ÎČ1 T869 C) and lymphotoxin-α (LT-α A252G) in patients having rheumatoid arthritis and correlate these patterns to disease activity and serum levels of tumor necrosis factor-alpha (TNF-α), B-Cell Activating Factor (BAFF), and osteopontin.MethodsA total of 194 subjects, 90 controls and 104 patients with rheumatoid arthritis were genotyped for MTHFR C677 T and A1298 C, TGF-ÎČ1 T869 C and LT-α A252G polymorphisms using a methodology based on PCR-RFLP. Also serum levels of TNF-α, osteopontin and BAFF were measured by ELISA kits.ResultsThe CT genotype and T allele of MTHFR C677 T and GG genotype and G allele of LT-α A252G are associated with the risk of RA and with higher levels of the pro-inflammatory cytokine, TNF-α in patients with rheumatoid arthritis.ConclusionOur findings suggest that there is association between MTHFR C677 T and LT-α A252G genes polymorphisms and increased risk of RA in this sample of Egyptian population
Polimorfismos dos genes metilenotetrahidrofolato redutase, fator de crescimento transformador ÎČ1 e linfotoxinaâα e susceptibilidade Ă artrite reumatoide
ResumoAntecedentesA artrite reumatoide Ă© uma doença autoimune amplamente prevalente com sugerida predisposição genĂ©tica.ObjetivosDetectar o padrĂŁo de polimorfismo dos genes metilenotetrahidrofolato redutase (MTHFR C677T e A1298C), fator de crescimento transformador ÎČ1 (TGFâÎČ1 T869C) e linfotoxinaâα (LTâα A252G) em pacientes com artrite reumatoide e correlacionar esses padrĂ”es com a atividade da doença e os nĂveis sĂ©ricos de fator de necrose tumoral alfa (TNFâα), fator ativador de linfĂłcitos B (BAFF) e osteopontina.MĂ©todosForam genotipados 194 indivĂduos â 90 controles e 104 com artrite reumatoide â Ă procura de polimorfismos dos genes MTHFR C677T e A1298C, TGFâÎČ1 T869C e LTâα A252G com uma metodologia baseada na PCRâRFLP. Mensuraramâse tambĂ©m os nĂveis sĂ©ricos de TNFâα, osteopontina e BAFF com kits de Elisa.ResultadosO genĂłtipo CT e o alelo T do MTHFR C677T e o genĂłtipo GG e alelo G do LTâα A252G estĂŁo associados ao risco de AR e a nĂveis mais elevados da citocina prĂłâinflamatĂłria TNFâα em pacientes com artrite reumatoide.ConclusĂŁoOs achados do presente estudo sugerem que hĂĄ associação entre os polimorfismos dos genes MTHFR C677T e LTâα A252G e um risco aumentado de AR nessa amostra da população egĂpcia.AbstractBackgroundRheumatoid arthritis is a widely prevalent autoimmune disorder with suggested genetic predisposition.ObjectivesThe aim of this study is to detect the pattern of genetic polymorphism of methylene tetrahydrofolate reductase (MTHFR C677T and A1298C), transforming growth factorâÎČ1 (TGFâÎČ1 T869C) and lymphotoxinâα (LTâα A252G) in patients having rheumatoid arthritis and correlate these patterns to disease activity and serum levels of tumor necrosis factorâalpha (TNFâα), BâCell Activating Factor (BAFF), and osteopontin.MethodsA total of 194 subjects, 90 controls and 104 patients with rheumatoid arthritis were genotyped for MTHFR C677T and A1298C, TGFâÎČ1 T869C and LTâα A252G polymorphisms using a methodology based on PCRâRFLP. Also serum levels of TNFâα, osteopontin and BAFF were measured by ELISA kits.ResultsThe CT genotype and T allele of MTHFR C677T and GG genotype and G allele of LTâα A252G are associated with the risk of RA and with higher levels of the proâinflammatory cytokine, TNFâα in patients with rheumatoid arthritis.ConclusionOur findings suggest that there is association between MTHFR C677T and LTâα A252G genes polymorphisms and increased risk of RA in this sample of Egyptian population
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