Comparison between rectangular and circular microstrip patch antenna arrays

In this paper, several designs of microstrip array antennas suitable for wireless communication applications are presented. This paper demonstrates several shapes of microstrip array antennas, such as rectangular and circular patch antenna arrays. Specifically, single, 2 × 1, and 4 × 1 elements of both shapes are designed and simulated by High Frequency Structural Simulator (HFSS). Moreover, this paper presents a comparison between both rectangular and triangular antenna arrays. Since the resonance frequency of these antennas is 2.4 GHz, these antennas are suitable for the ISM band and WLAN).</p

Comparative study of circular and rectangular microstrip patch antennas in Wi-Fi band

The growing ubiquity of Wi-Fi has necessitated the development of small and effective antenna designs, especially microstrip patch antennas. In the Wi-Fi frequency range of 2.4 GHz to 2.4835 GHz, this paper compares the performance of circular and rectangular microstrip patch antennas. The study aims to evaluate their performance regarding radiation characteristics, gain, and bandwidth to help choose antennas for Wi-Fi applications. According to the results, the rectangular patch antenna with a rectangular slot outperforms the circular patch antenna with a rectangular slot regarding return loss, coming in at roughly -37.07 dB. Furthermore, the Voltage Standing Wave Ratio (VSWR)value of the rectangular patch antenna is 1.02, which is higher than that of the circular patch antenna, which is 1.34. The rectangular patch antenna has the most excellent radiation efficiency (64.5%) and offers the broadest bandwidth (about 115 MHz). Engineers and researchers looking to enhance antenna designs for Wi-Fi applications can learn much from this study by considering variables like radiation efficiency, bandwidth, VSWR, and return loss.</p

Hydrochemical and isotopic characterization of a complex aquifer system

A methodology was developed and applied to the Tindouf basin (south-western Algeria) to understand the hydrogeology of a complex aquifer system with a limited number of data, to identify the favorable areas for the design and building of new wells, and to know whether there is still current recharge of these aquifers. The principal components analysis (PCA), diagram of deuterium versus oxygen-18, and equilibrium diagrams Mg/Na and Ca/Na were the techniques used to combine different datasets in order to identify chemical and isotopic groups, which were in turn used to define the groundwater flow paths. In addition, on the basis of thermodynamic equilibrium, it is possible to define the chemical evolution of the Tindouf basin aquifer. The results of this study are consistent with the generally accepted hydrogeological conceptual model. The combination of the different methods made possible to define and and to characterise the main groundwater flow paths from their sources to the discharge zones. These flow paths are defined by water categories, which are represented by salinity and groundwater origin. This approach can be used to analyze aquifers characterized by a lack of data and can also be useful for studying other complex groundwater basins

Optimisation du rendement propulsif d'une aile battante par la Méthode de Surface des Réponses

Dans la présente étude, le rendement propulsif d’un profil d’aile NACA0012 en mouvement de battement est optimisé à un nombre de Reynolds de Re = 1.1 × 10^4. Il s’agit d’une étude numérique 2D réalisée caractériser l’évolution du rendement propulsif en fonction des paramètres cinématiques de aile battante. Pour résoudre les équations de Navier-Stokes autour de l'aile battantes nous avons utilisé un solver 2D instationnaire avec un couplage Pression-Vitesse SIMPLEC. Pour la discrétisation spatiale on a utilisé le schéma convectif MUSCL de 3ème ordre avec une discrétisation temporelle du premier ordre. L'amplitude du mouvement de pilonnement, l’amplitude maximale du mouvement de tangage, la fréquence de battement et l’angle de phase entre ces deux mouvements sont considérés comme variables d’optimisation. Le battement du profil d’aile est réalisé grâce à l’utilisation des fonctions UDF et du module maillage dynamique, disponible dans Ansys Fluent. La Méthode des Surfaces des Réponses (MSR) est utilisé pour l’optimisation du rendement propulsif en fonction des paramètres cinématiques de l'aile. Un plan d’expérience complet avec 5 évaluations pour chaque variable a été élaboré pour conduire les simulations et obtenir les différentes combinaisons des paramètres de contrôle. Pour la prédiction de la réponse nous avons calculé les coefficients du méta-modèle de la MSR en utilisant des fonctions polynomiale . Le processus d’optimisation du méta-modèle est piloté par la technique du recuit simulé disponible sous MATLAB. Les résultats montrent que la méthode des surfaces de réponses est suffisamment robuste et donne, approximativement, les mêmes résultats que la méthode de montée de gradient. L’erreur relative entre le rendement propulsif obtenu par approximation en utilisant la RSM et celui obtenu par simulation numérique est très petite. Cela justifie très largement le recours à cette méthode. A la lumière des résultats obtenus, en plus de sa rapidité, la méthode des surfaces de réponse présente l’avantage d’être facile à implémenter, cependant, l’approximation quadratique qu’elle utilise est limitée à un certain nombre de variables d’optimisation

Genital-Sparing Cystectomy versus Standard Urethral-Sparing Cystectomy Followed with Orthotopic Neobladder in Women with Bladder Cancer: Incidence and Causes of Hypercontinence with an Ultrastructure Study of Urethral Smooth Muscles

BACKGROUND: Bladder cancer in women is an indication for radical cystectomy (RC) when the tumour is confined muscle-invasive bladder cancer (MIBC) of T2 N0M0, or high risk progressive non-muscle invasive bladder cancer (NMIBC). Radical cystectomy is either genital-sparing cystectomy (GSC) or standard urethra-sparing cystectomy (USC) that is followed with orthotopic ileal neobladder (ONB). Post-operative chronic retention “Hypercontinence†had been reported in different series following URS or GSC and ONB. In long-term follow-up, we evaluated the functional outcome of women who developed hypercontinence after USC or GSC and ONB. AIM: An ultrastructure study of female urethral smooth muscle was done to elucidate the underlying causes of hypercontinence. MATERIAL AND METHODS: Retrospective study was conducted on 71 women who underwent RC and ONB, 45women had undergone USC, and 26 women had GSC, follow-up ranged from 5 to 15 years. Ultrastructure studies were done on 5 urethral biopsy specimens from 5 women who had hypercontinence, and 4 biopsies were from a normal control. RESULTS: Follow-up showed that women who had undergone USC and ONB, 28.88% developed hypercontinence, where in the series of GSC and ONB three women out of 26 developed hypercontinence (7.80%). Three women who had hypercontinence following USC and ONB, they developed stones in the ileal pouch. Ultrastructure study of urethral smooth muscles in women who had hypercontinence showed organized collagen fibrils, absent myelin sheath, and non-detected lymphatic vessels. Normal urethra showed collagen fibrils within the interstitial matrix, preserved myelin sheath of nerve fibres, the presence of lymphatic vessels in the matrix. CONCLUSION: The present study shoes that GSC with ONB leads to the minimal incidence of hypercontinence (7.80%), while standard USC lead to higher incidence (28.88%). Ultrastructure changes of the female urethra who had hypercontinence were fibrotic changes, loss of myelin sheath and minimal vascularity, their findings explains the underlying cause of hypercontinence and support the technique of GSC rather than the standard USC

Anemia and Blood Transfusion in Patients with Isolated Traumatic Brain Injury

Rationale. By reducing cerebral oxygen delivery, anemia may aggravate traumatic brain injury (TBI) secondary insult. This study evaluated the impact of anemia and blood transfusion on TBI outcomes. Methods. This was a retrospective cohort study of adult patients with isolated TBI at a tertiary-care intensive care unit from 1/1/2000 to 31/12/2011. Daily hemoglobin level and packed red blood cell (PRBC) transfusion were recorded. Patients with hemoglobin < 10 g/dL during ICU stay (anemic group) were compared with other patients. Results. Anemia was present on admission in two (2%) patients and developed in 48% during the first week with hemoglobin < 7 g/dL occurring in 3.0%. Anemic patients had higher admission Injury Severity Score and underwent more craniotomy (50% versus 13%, p<0.001). Forty percent of them received PRBC transfusion (2.8 ± 1.5 units per patient, median pretransfusion hemoglobin = 8.8 g/dL). Higher hospital mortality was associated with anemia (25% versus 6% for nonanemic patients, p=0.01) and PRBC transfusion (38% versus 9% for nontransfused patients, p=0.003). On multivariate analysis, only PRBC transfusion independently predicted hospital mortality (odds ratio: 6.8; 95% confidence interval: 1.1–42.3). Conclusions. Anemia occurred frequently after isolated TBI, but only PRBC transfusion independently predicted mortality

Antimicrobial resistance among migrants in Europe: a systematic review and meta-analysis

BACKGROUND: Rates of antimicrobial resistance (AMR) are rising globally and there is concern that increased migration is contributing to the burden of antibiotic resistance in Europe. However, the effect of migration on the burden of AMR in Europe has not yet been comprehensively examined. Therefore, we did a systematic review and meta-analysis to identify and synthesise data for AMR carriage or infection in migrants to Europe to examine differences in patterns of AMR across migrant groups and in different settings. METHODS: For this systematic review and meta-analysis, we searched MEDLINE, Embase, PubMed, and Scopus with no language restrictions from Jan 1, 2000, to Jan 18, 2017, for primary data from observational studies reporting antibacterial resistance in common bacterial pathogens among migrants to 21 European Union-15 and European Economic Area countries. To be eligible for inclusion, studies had to report data on carriage or infection with laboratory-confirmed antibiotic-resistant organisms in migrant populations. We extracted data from eligible studies and assessed quality using piloted, standardised forms. We did not examine drug resistance in tuberculosis and excluded articles solely reporting on this parameter. We also excluded articles in which migrant status was determined by ethnicity, country of birth of participants' parents, or was not defined, and articles in which data were not disaggregated by migrant status. Outcomes were carriage of or infection with antibiotic-resistant organisms. We used random-effects models to calculate the pooled prevalence of each outcome. The study protocol is registered with PROSPERO, number CRD42016043681. FINDINGS: We identified 2274 articles, of which 23 observational studies reporting on antibiotic resistance in 2319 migrants were included. The pooled prevalence of any AMR carriage or AMR infection in migrants was 25·4% (95% CI 19·1-31·8; I2 =98%), including meticillin-resistant Staphylococcus aureus (7·8%, 4·8-10·7; I2 =92%) and antibiotic-resistant Gram-negative bacteria (27·2%, 17·6-36·8; I2 =94%). The pooled prevalence of any AMR carriage or infection was higher in refugees and asylum seekers (33·0%, 18·3-47·6; I2 =98%) than in other migrant groups (6·6%, 1·8-11·3; I2 =92%). The pooled prevalence of antibiotic-resistant organisms was slightly higher in high-migrant community settings (33·1%, 11·1-55·1; I2 =96%) than in migrants in hospitals (24·3%, 16·1-32·6; I2 =98%). We did not find evidence of high rates of transmission of AMR from migrant to host populations. INTERPRETATION: Migrants are exposed to conditions favouring the emergence of drug resistance during transit and in host countries in Europe. Increased antibiotic resistance among refugees and asylum seekers and in high-migrant community settings (such as refugee camps and detention facilities) highlights the need for improved living conditions, access to health care, and initiatives to facilitate detection of and appropriate high-quality treatment for antibiotic-resistant infections during transit and in host countries. Protocols for the prevention and control of infection and for antibiotic surveillance need to be integrated in all aspects of health care, which should be accessible for all migrant groups, and should target determinants of AMR before, during, and after migration. FUNDING: UK National Institute for Health Research Imperial Biomedical Research Centre, Imperial College Healthcare Charity, the Wellcome Trust, and UK National Institute for Health Research Health Protection Research Unit in Healthcare-associated Infections and Antimictobial Resistance at Imperial College London

International genome-wide meta-analysis identifies new primary biliary cirrhosis risk loci and targetable pathogenic pathways.

Primary biliary cirrhosis (PBC) is a classical autoimmune liver disease for which effective immunomodulatory therapy is lacking. Here we perform meta-analyses of discovery data sets from genome-wide association studies of European subjects (n=2,764 cases and 10,475 controls) followed by validation genotyping in an independent cohort (n=3,716 cases and 4,261 controls). We discover and validate six previously unknown risk loci for PBC (Pcombined<5 × 10(-8)) and used pathway analysis to identify JAK-STAT/IL12/IL27 signalling and cytokine-cytokine pathways, for which relevant therapies exist

Global estimates on the number of people blind or visually impaired by cataract: a meta-analysis from 2000 to 2020

Background: To estimate global and regional trends from 2000 to 2020 of the number of persons visually impaired by cataract and their proportion of the total number of vision-impaired individuals. Methods: A systematic review and meta-analysis of published population studies and gray literature from 2000 to 2020 was carried out to estimate global and regional trends. We developed prevalence estimates based on modeled distance visual impairment and blindness due to cataract, producing location-, year-, age-, and sex-specific estimates of moderate to severe vision impairment (MSVI presenting visual acuity &lt;6/18, ≥3/60) and blindness (presenting visual acuity &lt;3/60). Estimates are age-standardized using the GBD standard population. Results: In 2020, among overall (all ages) 43.3 million blind and 295 million with MSVI, 17.0 million (39.6%) people were blind and 83.5 million (28.3%) had MSVI due to cataract blind 60% female, MSVI 59% female. From 1990 to 2020, the count of persons blind (MSVI) due to cataract increased by 29.7%(93.1%) whereas the age-standardized global prevalence of cataract-related blindness improved by −27.5% and MSVI increased by 7.2%. The contribution of cataract to the age-standardized prevalence of blindness exceeded the global figure only in South Asia (62.9%) and Southeast Asia and Oceania (47.9%). Conclusions: The number of people blind and with MSVI due to cataract has risen over the past 30 years, despite a decrease in the age-standardized prevalence of cataract. This indicates that cataract treatment programs have been beneficial, but population growth and aging have outpaced their impact. Growing numbers of cataract blind indicate that more, better-directed, resources are needed to increase global capacity for cataract surgery.</p