Acid Transport Modeling Using Finite Element Discretization with Weak Formulation for Simulation of Acid Fracturing

The purpose of designing an acid fracturing model is to examine the two factors that measure the effectiveness of the acid fracturing treatment. The two factors are the acid penetration distance and the fracture conductivity after closure stress is reached. The acid fracturing model is designed by coupling a fracture propagation model and an acid transport model. The advanced fracture propagation models are developed numerically by the finite element method (FEM,) or the extended finite element method (XFEM.) However, the acid transport models that are reported in the literature are developed using the finite difference method (FDM.) The finite element method is a more stable and accurate technique to model different types of complex and coupled physics than FDM. Furthermore, FEM is a more powerful and suitable technique for meshing sophisticated geometries such as fractures. Thus, an acid transport model has been developed numerically using the finite element method. The developed model solves the Navier-Stokes equations numerically to get the velocity profile. The acid balance equation is solved considering the convection and diffusion terms in all direction of the fracture and not only across the fracture. This model considers the thermal effect by solving the energy balance equation without neglecting the temperature gradient along the fracture length and height. The developed model predicts accurate acid penetration distance with a relative error of 0.3% compared to the analytical solution, and improves the predicted acid-etched width by more than 8% compared to the reported analytical solutions, which overestimate the acid-etched width because of no taking into account the effect of wormholes when calculating the total leak-off coefficient. Finally, the fracture conductivity, after fracture closure, has been estimated by using correlations

Assessing Occupational Exposure to Surface Contaminants in Kuwaiti Educational Buildings

The prevalence of surface contaminants, such as potentially harmful bacteria, within building environments in the State of Kuwait is not known.To the authors’ knowledge, this article is the frst of such a report. A total of 342 stool samples were collected from 46 secondary schools to evaluate indoor occurrences of E. coli bacteria within selected lavatory surfaces. After microbiological testing, the results for the spread of the E. coli bacteria were categorized by total count, sampling location dependency, contamination level comparison between genders, and lavatory fxtures (i.e. seat and squat toilets). The results revealed that 7 schools have a bacterial contamination problem, there is cross-contamination between surfaces in the lavatory stalls, the boys’ lavatories were less sanitary than the girls’, and that the squat-style toilets are more contaminated than the seat-style. The results suggest that there is signifcant risk of spread of bacterial infection among students via contaminated hands and surfaces in the lavatory area in some schools. Thus, this study emphasizes the need to improve environmental hygiene and enhanced sanitation in these schools. In addition, conclusions can be drawn as to the effectiveness of the janitorial staff employed by the schools and the effcacy of the cleaning regime used in the lavatories. Furthermore, based on the fndings, there are architectural design consequences as squat-style toilets might be excluded in lavatories designed for schools to be constructed in the future

Elevated expression of the toll like receptors 2 and 4 in obese individuals: its significance for obesity-induced inflammation

BACKGROUND: Expression profile of the toll like receptors (TLRs) on PBMCs is central to the regulation of proinflammatory markers. An imbalance in the TLRs expression may lead to several types of inflammatory disorders. Furthermore, the dynamic regulation of inflammatory activity and associated impaired production of cytokines by peripheral blood mononuclear cells (PBMCs) in obese individulas remain poorly understood. Therefore, we determined the perturbation in TLRs (TLR2 and TLR4), their adaptor proteins (MyD88, IRAK1 and TRAF6) expression in PBMCs/subcutaneous adipose tissue (AT) as well as inflammatory cytokines changes in obese individuals. METHODS: mRNA expression levels of TLR2, TLR4, IL-6, TNF-α and adaptor proteins were determined by RT-PCR. TLR2, TLR4 and adaptor proteins expression in AT was determined by immunohistochemistry. RESULTS: Obese and overweight individuals showed significantly increased expression of TLR2, TLR4 and MyD88 in both PBMCs and AT as compared with lean individuals (P < 0.05). Interestingly, we found a remarkably higher expression of TLRs in obese and overweight individuals with type 2 diabetes (P < 0.05). Increased expression of TLR2, TLR4, MyD88 and IRAK1 correlated with body mass index (BMI) (TLR2: r = 0.91; TLR4: r = 0.88, P <0.0001; MyD88: r = 0.95, P < 0.0001; IRAK1 r = 0.78, P < 0.002). TLRs’ expression was also correlated with fasting blood glucose (FBG) (TLR2: r = 0.61, P < 0.002; TLR4: r = 0.52, P < 0.01) and glycated haemoglobin (HbA1c) ( TLR2: r = 0.44, P <0.03; TLR4: r = 0.48, P < 0.03). Transcript levels of IL-6 and TNF-α were highly elevated in obese subjects compared to lean subjects. There was a strong association of TLRs’ expression in PBMCs with TNF-α (TLR2: r = 0.92; TLR4: r = 0.92; P < 0.0001) and IL-6 (TLR2: r = 0.91, P < 0.0001; TLR4: r = 0.81; P < 0.001). Similarly adaptor proteins were significantly correlated with TNF-α (MyD88: r = 0.9, P < 0.0001; IRAK1: r = 0.86; P < 0.0002) and IL-6 (MyD88: r = 0.91, P < 0.0001; IRAK1: 0.77; P < 0.002). CONCLUSIONS: TLRs and adapter proteins were overexpressed in PBMCs from obese subjects, which correlated with increased expression of TNF-α and IL-6. This association may explain a potential pathophysiological link between obesity and inflammation leading to insulin resistance

Unilateral cross bite treated by corticotomy-assisted expansion: two case reports

<p>Abstract</p> <p>Background</p> <p>True unilateral posterior crossbite in adults is a challenging malocclusion to treat. Conventional expansion methods are expected to have some shortcomings. The aim of this paper is to introduce a new technique for treating unilateral posterior crossbite in adults, namely, corticotomy-assisted expansion (CAE) applied on two adult patients: one with a true unilateral crossbite and the other with an asymmetrical bilateral crossbite, both treated via modified corticotomy techniques and fixed orthodontic appliances.</p> <p>Methods</p> <p>Two cases with asymmetric maxillary constriction were treated using CAE.</p> <p>Results</p> <p>In both cases, effective asymmetrical expansion was achieved using CAE, and functional occlusion was established as well.</p> <p>Conclusions</p> <p>Unilateral CAE presents an effective and reliable technique to treat true unilateral crossbite.</p

Data Replication and Fault Tolerance in AsterixDB

AsterixDB is a Big Data Management System (BDMS) that is designed to run on large clusters of commodity hardware. In such clusters however, hardware failures are inevitable. To tolerate these failures, data replication strategies are used. Over the years, many data replication strategies have been proposed with different trade-offs between data consistency, throughput, and recovery time.In this thesis, we describe our new data replication protocol for AsterixDB that guar- antees data consistency and exploits the properties of Log-Structured Merge-trees to achieve efficient data replication and controllable recovery time. We explain in detail the data replication protocol design and implementation. We then explain how fault tolerance is im- plemented on top of the data replication protocol. We further provide an initial evaluation of the data replication protocol and show how three replicas of the data can be maintained with only 6% to 14% increase in ingestion time for certain ingestion workloads. We also show how a recovery time as low as one second can be achieved

Three distinct clones of carbapenem-resistant Acinetobacter baumannii with high diversity of carbapenemases isolated from patients in two hospitals in Kuwait

SummaryObjectivesThis study was undertaken to investigate the clonal relatedness of multidrug-resistant (MDR) Acinetobacter baumannii isolates collected from patients in two teaching hospitals in Kuwait.Materials and methodsClinically significant consecutive isolates of A. baumannii obtained from patients in the Mubarak (36) and Adan (58) hospitals over a period of 6 months were studied. These isolates were identified using molecular methods, and their antimicrobial susceptibility was determined by the Etest method. The mechanism of resistance to carbapenem was investigated by PCR, and pulsed-field gel electrophoresis (PFGE) was used to determine the clonal relatedness of MDR isolates.ResultsOf the 94 isolates investigated, 80 (85.1%) were multidrug resistant (MDR). The A. baumannii PFGE clone A and subclone A1 were the most prevalent in patients infected with MDR isolates. Fifty-five (94.8%) and 15 (41.7%) of the MDR isolates from the Adan and Mubarak hospitals, respectively, belonged to PFGE clone A; isolates in this group showed higher resistance rates to antibiotics than isolates form other groups. Of the 94 isolates, 40 (42.6%) were resistant to either imipenem or meropenem or to both (CRAB). Most CRAB isolates (29/40 or 72.5%) carried bla genes, which code for MBL (VIM-2 and IMP-1) enzymes. Two isolates harbored blaOXA-23.ConclusionThree distinct clones of CRAB were isolated, providing evidence of a high diversity of carbapenemases among our geographically related isolates

An Assessment of Indoor Environmental Quality in School Buildings in the State of Kuwait

In this study, indoor quality and environmental comfort were investigated in secondary school buildings located in the State of Kuwait. Comfort variables such as temperature and relative humidity (thermal comfort), noise (acoustic comfort), illumination (visual comfort), as well as allocated classroom floor area per student (spatial comfort) were measured. Data was collected over a 7-month period on a spot basis during school hours in student-occupied classrooms at 46 selected schools. The measured data was then compared to international guidelines and standards related to indoor environment quality. The data for noise and allocated space were shown to be in the comfort ranges in all the schools. However, 11% of the schools are not adequately illuminated, 33% had temperatures not within the recommended limits, and 22% of the schools had humidity levels either higher or lower than the recommended levels. Also, 9% of the schools had low illumination readings.In addition, during the data monitoring, a survey was conducted by which the student occupants completed a questionnaire so that subjective and objective evaluations could be compared. The findings of the questionnaire displayed significant correlations between the measured data and some ailments and other complaints experienced by the students.Ultimately, the results found in this research will provide a baseline for comparison with future indoor environment quality assessments in buildings. Furthermore, recommendations are suggested in order to improve the environmental quality problems encountered in some of the schools, which may be beneficial for policymakers, facilities managers, and design engineers.

An Assessment of Indoor Environmental Quality in School Buildings in the State of Kuwait

In this study, indoor quality and environmental comfort were investigated in secondary school buildings located in the State of Kuwait. Comfort variables such as temperature and relative humidity (thermal comfort), noise (acoustic comfort), illumination (visual comfort), as well as allocated classroom floor area per student (spatial comfort) were measured. Data was collected over a 7-month period on a spot basis during school hours in student-occupied classrooms at 46 selected schools. The measured data was then compared to international guidelines and standards related to indoor environment quality. The data for noise and allocated space were shown to be in the comfort ranges in all the schools. However, 11% of the schools are not adequately illuminated, 33% had temperatures not within the recommended limits, and 22% of the schools had humidity levels either higher or lower than the recommended levels. Also, 9% of the schools had low illumination readings.In addition, during the data monitoring, a survey was conducted by which the student occupants completed a questionnaire so that subjective and objective evaluations could be compared. The findings of the questionnaire displayed significant correlations between the measured data and some ailments and other complaints experienced by the students.Ultimately, the results found in this research will provide a baseline for comparison with future indoor environment quality assessments in buildings. Furthermore, recommendations are suggested in order to improve the environmental quality problems encountered in some of the schools, which may be beneficial for policymakers, facilities managers, and design engineers. </jats:p