Minia University

About: Minia University is a education organization based out in Minya, Egypt. It is known for research contribution in the topics: Population & Medicine. The organization has 4967 authors who have published 8986 publications receiving 108384 citations.

Challenges and opportunities for a European HVDC grid

Abstract: In 2009 the European governments committed their countries to a reduction in green-house-gas emissions up to 80% by 2050. Consequently, the employment of renewable energies has been strongly encouraged, making the upgrade of the existing AC grid necessary. Several associations are considering whether it would be more beneficial to build an HVDC grid instead. The main objective of the current study is to investigate possibilities and challenges in relation to the installation of a European HVDC grid. Most suitable technologies and possible configurations have been identified. Applications and existing projects of HVDC have been briefly mentioned. After examining various Supergrids models, financial aspects resulted challenging, since big investments are required. From a technical point of view, further research for DC voltage control and protection strategies is required. The publication of the HVDC Grid Codes represents a first step towards a European energy union; requirements are however not fully mandatory in all nations yet. The most probable development of the future HVDC grid has been defined: the grid is not expected to be built at once, but rather to develop in an organic way. In this sense, the installation of an offshore grid would be highly beneficial. Studies of possible supergrid architectures are still controversial and in part superficial. A solution to solve those lacks and achieve an agreement would be a strict collaboration between existing associations and involved European countries.

Chemistry of Pyrazolopyrimidines

Abstract: Publisher Summary The interesting biological activities reported for pyrazolopyrimidines have stimulated chemists to develop the chemistry of this class of compounds. This chapter appears to be the first survey of the chemistry and biological activity of this class of compounds. Condensation of β-keto esters with 3( 5)-aminopyrazoles has been used extensively to synthesize pyrazolo[ 1,5-a]pyrimidines. Theoretically, two isomeric pyrazolo[ 1,5-a] pyrimidines can be produced. The parent pyrazolo pyrimidine has been synthesized via cyclocondensation of 1-unsubstituted 3(5)-aminopyrazoles (12) with malonodialdehyde tetramethylacetate. This approach was used to synthesize several substituted pyrazolo pyrimidines. 3- Oxoalkanonitriles and their functional derivatives condense readily with 12 to yield 7-aminopyrazolo. And benzoylacetonitrile and its p-chlorophenylazo and acetylbenzyl cyanide derivatives react with β-cyanoethylhydrazine (74) to yield pyrazolo pyrimidines formed via l-β-cyanoethyl-5-aminopyrazole intermediates. The chapter also discusses chemical properties of pyrazolo[ 1,5-a]pyrimidines and pyrazolo[3,4-d]pyrimldines and elaborates on theoretical methods, spectra, and tautomerism.

Determinants of sexual disability and dissatisfaction in female patients with rheumatoid arthritis

Abstract: Previous research has identified two main problems of sexuality in female rheumatoid arthritis (RA) patients: difficulties in sexual performance and diminution of sexual desire and satisfaction. This study attempts to determine the clinical and psychological factors significantly contributing to sexual disability and dissatisfaction in female RA patients. Ninety consecutive female RA outpatients were assessed by a gynecologist. After excluding patients who were not sexually active and those with genital tract abnormalities, 52 patients were examined and investigated rheumatologically and given questionnaires assessing sexual performance, desire, and satisfaction, as well as demographic variables, pain, disability, anxiety, and depression. Following a correlation analysis, the contributions of demographic, disease, and psychological variables to sexual disability and dissatisfaction were explored by hierarchical and stepwise regression. Thirty-two patients (62%) had difficulties in sexual performance including nine patients (17%) who were totally unable to engage in sexual intercourse because of arthritis. Sexual desire or satisfaction were diminished in 24 patients (46%) and completely lost in 24 patients (46%). Sexual disability was not significantly correlated with any psychodemographic variables, but with parameters of disease activity (p<0.001), Health Assessment Questionnaire (HAQ)-disability (p<0.001), hip (p<0.001) but not knee joint disease, seropositivity (p<0.05), and diminished desire (p<0.05). However, HAQ-disability and hip joint disease were the only independent and significant determinants of sexual disability in the regression model after controlling for the effects of age and disease duration. These variables together explained 64% of the variance of sexual disability. On the other hand, pain (p<0.001), age (p<0.05), and depression (p<0.05) were the significant determinants in the regression model for sexual dissatisfaction, all together contributing 36% of its variance. More than 60% of female RA patients experience variable degrees of sexual disability and diminished sexual desire and satisfaction. Difficulties in sexual performance are related more to overall disability and hip involvement, while diminished desire and satisfaction are influenced more by perceived pain, age, and depression.