Quantitative structure-activity relationship for antimalarial activity of artemisinin

The increase in resistance to older drugs and the emergence of new types of infection have created an urgent need for discovery and development of new compounds with antimalarial activity. Quantitative-Structure Activity Relationship (QSAR) methodology has been performed to develop models that correlate antimalarial activity of artemisinin analogs and their molecular structures. In this study, the data set consisted of 197 compounds with their activities expressed as log RA (relative activity). These compounds were randomly divided into training set (n=157) and test set (n=40). The initial stage of the study was the generation of a series of descriptors from three-dimensional representations of the compounds in the data set. Several types of descriptors which include topological, connectivity indices, geometrical, physical properties and charge descriptors have been generated. The number of descriptors was then reduced to a set of relevant descriptors by performing a systematic variable selection procedure which includes zero test, pairwise correlation analysis and genetic algorithm (GA). Several models were developed using different combinations of modelling techniques such as multiple linear regression (MLR) and partial least square (PLS) regression. Statistical significance of the final model was characterized by correlation coefficient, r2 and root-mean-square error calibration, RMSEC. The results obtained were comparable to those from previous study on the same data set with r2 values greater than 0.8. Both internal and external validations were carried out to verify that the models have good stability, robustness and predictive ability. The cross-validated regression coefficient (r2 cv) and prediction regression coefficient (r2 test) for the external test set were consistently greater than 0.7. The QSAR models developed in this study should facilitate the search for new compounds with antimalarial activity

The effect of laparoscopic sleeve gastrectomy on erectile and sexual function in obese adult men

Background: Obesity is often associated with multiple negative health-related comorbidities. There is an increased risk of sexual dysfunction in the obese population. Although multiple studies reported significant improvement of these complaints after different bariatric surgeries, there are few studies evaluating the role of laparoscopic sleeve gastrectomy (LSG) on this specific outcome. Objective: This study was conducted to evaluate the effect of LSG on sexual function in male patients with morbid obesity. Patients and methods: This prospective study included 114 morbid obese patients with erectile dysfunction (ED). All patients underwent the conventional LSG. Sexual function was evaluated using the International Index of Erectile Function (IIEF) score before surgery, then after six and 12 months after surgery. The severity of ED was evaluated according to the erectile function component of the same previous score.Results: The one-year % of excess weight loss (EWL) had a mean value of 61.18%. At the same visit, there was a significant improvement in the total IIEF score from 49.04 to 67.88, erectile function from 18.25 to 25.94, orgasm function from 6.99 to 9.41, sexual desire from 7.06 to 9.35, intercourse satisfaction from 9.25 to 13.56, and overall satisfaction from 7.49 to 9.61. A significant positive association was noted between the % EWL and the total IIEF score and its components. Conclusion: LSG led to significant improvement of sexual and erectile dysfunction in obese male patients. Weight loss led to a significant decline in the prevalence of ED, and if the problem did not resolve, its severity would be markedly decreased

Concomitant versus delayed cholecystectomy in morbidly obese patients with asymptomatic gall stones undergoing laparoscopic sleeve gastrectomy

Background: Performing cholecystectomy concomitant to laparoscopic sleeve gastrectomy (LSG) in morbidly obese patients with asymptomatic cholelithiasis is poorly discussed.Objectives: We conducted the current investigation to compare concomitant to late cholecystectomy in asymptomatic gall stone patients undergoing LSG.Patients and methods: One hundred morbid obese patients scheduled for LSG were included in this retrospective analysis. They were divided into two groups: Group 1 included patients who underwent concomitant cholecystectomy, and group 2 that included patients who omitted such a procedure. Delayed cholecystectomy was scheduled if the patient developed symptoms related to gall bladder disease. The incidence of post-operative complications and percentage of developing symptomatic cholelithiasis in group 2 were our outcomes. Results: All preoperative data were statistically comparable between the two groups. However, operative time and intraoperative blood loss were significantly increased in group 1. The incidence of total early post-operative complications also increased in the same group (14% vs 0% in the other group). In Group 1, we encountered two patients with intraperitoneal bleeding (4%) who required laparoscopic management, in addition to the other two cases with biliary leakage (4%). In group 2, 18% of patients expressed symptomatic gall stone disease before the scheduled operation, while two cases (4%) developed acute complications that required early cholecystectomy. Conclusion: Cholecystectomy is associated with an increased incidence of early post-operative complications when performed in association with LSG. However, about 25% of asymptomatic cases who omitted the concomitant procedure will develop symptoms before the scheduled cholecystectomy

Formal Probabilistic Analysis of a Wireless Sensor Network for Forest Fire Detection

Wireless Sensor Networks (WSNs) have been widely explored for forest fire detection, which is considered a fatal threat throughout the world. Energy conservation of sensor nodes is one of the biggest challenges in this context and random scheduling is frequently applied to overcome that. The performance analysis of these random scheduling approaches is traditionally done by paper-and-pencil proof methods or simulation. These traditional techniques cannot ascertain 100% accuracy, and thus are not suitable for analyzing a safety-critical application like forest fire detection using WSNs. In this paper, we propose to overcome this limitation by applying formal probabilistic analysis using theorem proving to verify scheduling performance of a real-world WSN for forest fire detection using a k-set randomized algorithm as an energy saving mechanism. In particular, we formally verify the expected values of coverage intensity, the upper bound on the total number of disjoint subsets, for a given coverage intensity, and the lower bound on the total number of nodes.Comment: In Proceedings SCSS 2012, arXiv:1307.802

Terrorism The Phenomenon that has no Common Consent on its definition

Recently, the world has witnessed arbitrary acts of terrorism and violence carried out by various individuals and/or organizations. The significance of studying terrorism - whatever the focus in such a potential study is - lies in that numerous international legal principles that are firmly established in international treaties or conventions have now become subject to controversy or - at least - have lost their practical value owing to different reactions vis - à - vis this phenomenon. Undoubtedly, many studies have explored the phenomenon of terrorism in order to decipher the main motives behind its spread and to furnish relevant, appropriate and effective remedies. These studies, however, have been politically influenced, and therefore, were hindered and have become unable to arrive at a clear and neutral definition of terrorism. The study highlights the significance of finding a definition of terrorism. It also deals with the attempts which were made to define terrorism through international treaties and UN resolutions. The study further shows that despite the attempts referred to above no success has been witnessed in terms of constructing a clear, definition of ‘terrorism’. The persistence of the ambiguity surrounding the concept of ‘terrorism’ will always remain a stumbling block that hampers any endeavor to reach a comprehensive and effective way of objectively tackling this phenomenon and that impedes the various efforts made worldwide in this direction

A Charge Controller Based on Microcontroller in Stand-Alone Photovoltaic Systems

AbstractPV systems have spread widely all over the world. Charge controllers are needed to improve the efficiency of the PV systems and to protect the storage batteries. The main function of charge controller in PV systems is to charge the battery without permitting over charge and deep discharge. An intelligent charge controller has been designed with the object of prolonging battery life. The need for and advantages of such charge controllers are discussed and tests have been performed and applied on prototype which is versatile and has provision for more monitoring and control functions than that of the conventional logic and relay controller

DNA-based routes to metal, inorganic and polymer nanowires

PhD ThesisThis thesis describes the preparation and characterization of conductive nanowires. The synthesis of the nanowires was achieved using a DNA-templating strategy. The chemical identity of the nanowires was characterized using FTIR, XPS and XRD, while the structural character, electronic properties and magnetic behavior were probed using AFM, EFM and MFM, respectively. The formation of Fe3O4 nanowires involved initial association of Fe²+ and Fe³+ ions to the DNA, and subsequent co-precipitation of the Fe3O4 material, upon addition of NaOH. Chemical characterization confirmed the formation of Fe3O4 within the product material. AFM data revealed one-dimensional (1-D) nanostructures with diameters up to 30 nm, whilst EFM and MFM showed that the nanowire structures are electrically conducting and exhibit magnetic behaviour. The preparation of Fe and Rh nanowires, respectively, was achieved by DNA-templating approach in conjunction with either chemical or electrochemical reduction. Chemical characterization confirmed a metal/oxide core/shell structure. AFM data showed 1-D nanostructures with granular character, and diameters up to 26 nm for Fe and 31 and 23 nm for Rh, respectively. The structures were confirmed to be electrically conducting and to display magnetic behaviour as indicated by EFM and MFM, respectively. Finally, DNA-templating of 2,6-diaminopurine-propyl-2,5 bis-dithenyl pyrrole and thymine-propyl-pyrrole by chemical oxidation using FeCl3 yielded supramolecular polymers. FTIR and XPS studies confirmed the presence and interaction of the component polymer chains. The DNA/CPs nanowires showed smooth and uniform structures with diameters up to 25 and 35 nm, and they were found to be electrically conducting. The attempted formation of larger structures based on the base pair hydrogen bonding between the two types of nanowires was investigated by AFM studies. However, reliable evidence for larger structures formation based on this specific interaction was not found.The Ministry of Higher Education, Libya

Model for the Automated Generation of Optimized Work Packages in Results-Based-Finance Mega Sanitation Projects

The sanitation sector is one of the critical sectors in any country. The lack of proper sanitation systems causes many environmental hazards that threaten people’s health and well-being. In many developing countries, the sanitation sector constitutes a significant part of their strategic plans of reform. However, with the public treasury’s very limited budget, countries opt to major lending institutions for funds. “Results-Based-Finance” is a new funding mechanism used by many lending institutions. The mechanism has proven its efficiency in achieving the necessary reform in sanitation sectors. Due to the complexity of the funding tool, it is crucial to be able to decompose the project into smaller packages to be able to manage and control the project effectively. The objective of this dissertation is to reach an optimum packaging scheme that enables mega sanitation infrastructure projects to be successfully managed through better planning and cost control practices. The model aim shall be to minimize the amount of funds needed from the borrowing country through three options: by reducing the peak value of the negative cashflow curve, by normalizing the negative cashflow curve, or by a combination of the previous two objectives. With the aid of Unified Modelling Language (UML), an algorithm is developed to map the logic behind the model suggested with detailed illustrations of its different modules. Object-oriented processes and operations are modeled using various diagrams of the language, which automatically generate the optimum packaging combination. The packaging model is then implemented via a number of computer-aided programs. Microsoft Excel is used for calculation purposes. Visual Basic for Applications (VBA) programming language is used to make the model user-friendly for non-engineering stakeholders. Palisade\u27s Decision Tools Suite is used for the genetic algorithm optimization process. In order to verify the model, different approaches have been used, which include system checks to minimize programming errors. Moreover, a sensitivity analysis module has been designed with the aid of Top Rank software in order to ensure the flexibility and the capabilities of the constructed model. After the model verification is conducted, the model shall be validated using data from a case study of a mega sanitation results-based financed project located in Egypt. The project is achieved through the World Bank and aims to strengthen the Egyptian Institutions for better service delivery by providing incentives. The project worth is 550 Million USD. The ability of the model to plot the optimization process and the suggested outputs is proven feasible. The model output is not only the content of the packages but also a complete managing plan which demonstrates much useful information to the decision-makers and government officials. Moreover, the model has reduced the peak value of the negative cashflow curve by 18.7 percent, normalized the negative cashflow curve by 5.4 percent, and the model has reduced the funding gap in general by 8.9 percent

Bahraini School English Language Teachers’ Beliefs and Professionalism under New Educational Reforms in Bahrain: An Interpretive Perspective

This study sought to explore Bahraini teachers’ beliefs about teaching and learning as they related to their daily work and their interactions with the contexts in which they worked and lived so as to construct a deeper understanding of their professionalism. It particularly investigated the effects of contextual factors, in light of the recent educational reform initiatives in Bahrain, on the professional lives of practicing Bahraini school English language teachers who completed a Post Graduate Diploma in Education (PGDE) at Bahrain Teachers College (BTC) between 2008 and 2012. Research data were collected through face-to-face semi-structured in-depth interviews with twelve teachers in the primary, intermediate and secondary schools, whose experiences ranged between four to ten years at the time of the interviews. The research revealed that the teachers’ professional lives were influenced by three main contextual factors: intensification of teachers’ work, marginality of teachers and control in education. These factors were found to be complex as they were not only influenced by the educational system and the environment in which the teachers worked and lived but also by personality issues. Hence, although these factors significantly impacted upon the teachers’ professional autonomy and commitment, created moral dilemmas for them, and brought with them the question of what it means to be a teacher under increasing scrutiny, the findings showed that the consequences of these factors on the teachers’ professionalism varied from teacher to teacher and from context to context, emphasising that this impact was largely mediated by the teachers’ values and sense of professional identity. The study highlights the situated nature of teachers’ beliefs and the importance of considering teachers’ professional identities, values and moral purposes in any educational reform attempts that aim to improve teacher practice. This study also has implications for teacher beliefs and knowledge, teacher professionalism, and teacher education