Atomistic Origins of Various Luminescent Centers and n-Type Conductivity in GaN: Exploring the Point Defects Induced by Cr, Mn, and O through an Ab Initio Thermodynamic Approach.

GaN is a technologically indispensable material for various optoelectronic properties, mainly due to the dopant-induced or native atomic-scale point defects that can create single photon emitters, a range of luminescence bands, and n- or p-type conductivities. Among the various dopants, chromium and manganese-induced defects have been of particular interest over the past few years, because some of them contribute to our present-day light-emitting diode (LED) and spintronic technologies. However, the nature of such atomistic centers in Cr and Mn-doped GaN is yet to be understood. A comprehensive defect thermodynamic analysis of Cr- and Mn-induced defects is essential for their engineering in GaN crystals because by mapping out the defect stabilities as a function of crystal growth parameters, we can maximize the concentration of the target point defects. We therefore investigate chromium and manganese-induced defects in GaN with ab initio methods using the highly accurate exchange-correlation hybrid functionals, and the phase transformations upon excess incorporation of these dopants using the CALPHAD method. We also investigate the impact of oxygen codoping that can be unintentionally incorporated during crystal growth. Our analysis sheds light on the atomistic cause of the unintentional n-type conductivity in GaN, being ON-related. In the case of Cr doping, the formation of CrGa defects is the most dominant, with an E +/0 charge transition at E VBM + 2.19 eV. Increasing nitrogen partial pressure tends to enhance the concentration of CrGa. However, in the case of doping with Mn, several different Mn-related centers can form depending on the growth conditions, with MnGa being the most dominant. MnGa possesses the E 2+/+, E +/0, and E 0/- charge transitions at 0.56, 1.04, and 2.10 eV above the VBM. The incorporation of oxygen tends to cause the formation of the MnGa-VGa center, which explains a series of prior experimental observations in Mn-doped GaN. We provide a powerful tool for point defect engineering in wide band gap binary semiconductors that can be readily used to design optimal crystal growth protocols.

Secondary attack rates and determinants of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) household transmission in Pakistan: A case-ascertained prospective, longitudinal study.

BACKGROUND: Households are considered ideal settings for studying the transmission dynamics of an infectious disease. METHODS: A prospective study was conducted, based on the World Health Organization FFX protocol from October 2020 to January,2021. Household contacts of laboratory-confirmed index cases were followed up for their symptomatic history, nasal swabs for RT-PCR,and blood samples for anti-SARS CoV-2 antibodies were collected at enrollment and days 7, 14 and 28. We estimated secondary attack rate (SAR), effective household case cluster size and determinants of secondary infection among susceptible household contacts using multivariable logistic regression. RESULTS: We enrolled 77 index cases and their 543 contacts. Out of these, 252 contacts were susceptible at the time of enrollment. There were 77 household clusters, out of which, transmission took place in 20 (25.9%) giving rise to 34 cases. The acquired secondary attack rate (SAR) was 14.0% (95% CI 9.0-18.0). The effective household case cluster size was 0.46 (95%CI 0.33,0.56). Reported symptoms of nausea and vomiting (aOR, 7.9; 95% CI, 1.4-45.5) and fatigue (aOR, 9.3; 95% CI, 3.8-22.7) were associated with SARS-CoV-2 transmission. CONCLUSIONS: We observed a low SARS-CoV-2 secondary attack rate in the backdrop of high seroprevalence and asymptomatic transmission among households in Karachi, Pakistan.

Donatio organorum- reluctance to organ donation medical students; a cross-sectional descriptive study.

Introduction: Organ donation is the act of removing an organ or tissue from a donor and transplanting the said organ/tissue to a recipient. Despite being the only definitive treatment for end-organ failure, there is a lot of hesitation surrounding the practice of organ donation. Even among medical students, who are more aware of the benefits of organ donation than the general public, this reluctance is widespread.Therefore, we conducted this research to determine the basis of this skepticism, so that the root causes can be identified and eradicated. Our research sought to ascertain the overall attitudes of Rawalpindi Medical University, Pakistan's students towards organ donation, the associated factors that influenced this attitude (religious devotion, gender, age, year of study) and the reasons for the hesitance. Methods: A cross-sectional study targeting the students of first to final year MBBS was conducted at Rawalpindi Medical University, Pakistan in the year 2022. The sample size was calculated using OpenEpi software, and came out to be 292. The students enrolled at Rawalpindi Medical University during the year 2021-2022 were made a part of the study. A self-structured questionnaire that was developed after substantial research was used to collect the data using a non-random convenience sample technique. Chi Square test was used to determine significance after data analysis using SPSS-22. Results: A total of 290 students participated in the study, 58 from each year. All of the participants were Muslim. A very strong correlation was found between high devoutness and willingness towards organ donation (p = 7.4252E-13). Only 9/290 (3%) of people in Pakistan have joined The Transplantation Society of Pakistan; the main cause of this low ratio is that very few people were aware that such a group even existed (according to 62% of the responders). The mistrust of doctors and the belief that appropriate efforts would not be done to resuscitate patients who have signed up for organ donation is a significant factor in the anxiety surrounding organ donation. Conclusions: There are several reasons why people are reluctant to donate their organs, including a lack of understanding of religious perspectives on the subject, mistrust of medical professionals and medical administration, and general public ignorance. We can make a significant progress toward closing the gap between the demand for and supply of organ donations if these problems are remedied. The most effective strategy to stop organ trafficking is through organ donation. Through seminars, conversations, and workshops, we need to raise awareness about organ donation.

Awareness of mothers coming to obstetric wards of allied hospitals regarding neonatal care and the working of community health workers in their districts.

Introduction: Neonatal mortality remains a significant challenge not only to the world,but especially to a developing country like Pakistan. It can be majorly attributed to the sub-par healthcare, insufficient and under-recognised community health workers, and the lack of knowledge of proper newborn care on the part of the parents. This study targets the level of knowledge of the mothers and the services provided by community health care workers as the main factors determining neonatal care. Methods: A cross-sectional study was conducted in the OBS (obstetrics) wards of Hospitals affiliated with Rawalpindi Medical University from January 2022 to June 2022. The sample size was 138. Data was collected by one-on-one interviews, using a standardized USAID Community Health Worker Assessment and Improvement Matrix questionnaire. Data analysis was done using SPSS v28. Chi-square test was applied to check for significance. Results: Out of the total 138 participants, 47.8% (n = 66/138) were between the ages of 21-25. Results showed that women between the ages of 21-25 (P = 0.000058) and women who had their first child between the ages of 23-27 had good knowledge about neonatal care. 45% (n = 62/138) of the participants had poor knowledge of neonatal care, whereas 55% (n = 76/138) had good knowledge (P = 0.000002). As for the role of community health workers, only 20-30% of the participants were being provided with their services; hence their performance was not found to be adequate. Conclusions: The world of medicine is moving rapidly toward a new framework of the health systems in which the real foundation will be based on what actually takes place in the community, therefore, community health workers can play an important role in improving maternal and neonatal care. Family-centered care, appropriate age of first conception and motherhood, and proper guidance to first-time parents can ensure significant improvement in neonatal care in the future.