First-principles density functional theory based electronic structure calculations of some zinc-oxide and zinc-sulphide polymorphs

Recently, zinc oxide (ZnO) and zinc sulfide (ZnS) have drawn a resurgent attention in the research community due to their interesting properties with diverse potential applications. Wide bandgap, large exciton binding energy at room temperature, and small effective electron mass and piezoelectricity make ZnO a potential candidate for a variety of electronic and optoelectronic devices. ZnS possesses a direct bandgap of 3.6 eV at room temperature and appears to be a promising candidate for a broad range of technological applications including transparent conductors, visual displays and high-density optical memories. However, in order to realize the efficient utilization of ZnO and ZnS in blue, green and ultraviolet (UV) emitters with high efficiency, it is very important to modify these materials so that the full bandgap energy spectrum (from visible to UV) may be covered by the materials. Alloying of ZnO with sulfur (S) chalcogen reveals vivid changes in its electronic and optical properties due to the dramatic restructuring of electronic structure. In this thesis, the structural, electronic and optical properties of pure ZnO and ZnO1-xSx (x = 0, 0.25, 0.50, 0.75 and 1) alloys in wurtzite (WZ), sphalerite type, germanium phosphide (GeP) type, 5-5 type, nickel arsenide (NiAs) type, ß-beryllium oxide (BeO) type, and cesium chloride (CsCl) type are studied by using full-potential linearized augmented plane wave plus local orbital (FPLAPW + lo) method within density functional theory (DFT). The structural properties of pure ZnO and S-doped ZnO in seven crystal structures were calculated by using Perdew-Burke-Ernzerhof – generalized gradient approximation (PBE – GGA) exchange correlation whereas the calculations for electronic and optical properties were carried out by adding the mBJ potential to the PBE-GGA exchange correlation. The structural properties of S-doped ZnO in seven polymorphs reveal a small deviation from Vegard’s law which is consistent with the findings from previous literature. It was found that the replacement of the oxygen (O) atom by S produces interesting effects on the band structures of ZnOS alloys. The electronic bandgaps of ZnOS alloys in WZ structure, sphalerite type and BeO type were enhanced from 2.65 eV to 3.68 eV, 2.50 eV to 3.60 eV and 2.85 eV to 3.75 eV, respectively. The bandgap of 5-5 type ZnOS alloys decreases from 3.12 eV to 2.63 eV and the band structures of GeP type and NiAs type ZnOS alloys show different variations with different concentrations. On the other hand, CsCl type ZnOS alloys exhibit a metallic nature. The static dielectric constants of the seven considered polymorphs reveal that the polarization of the S doped ZnO increases by increasing the S concentration. The CsCl type ZnOS alloys with metallic character were found to have the highest value of static dielectric constant. The results for optical properties show that the incorporation of S atoms moves the maximum absorption, reflectivity and conductivity peaks towards low photon energies which reveal the potential of S doped ZnO. The static refractive indices of all considered ZnOS alloys were found to be increased by increasing the S content. The analysis of the absorption spectra shows that WZ structure, sphalerite type and BeO type ZnOS alloys are the promising candidates for visible and UV photoelectronic devices. The 5-5 type and NiAs type ZnOS ZnOS alloys were found suitable for visible light regime applications. On the other hand, GeP type ZnOS alloys are best for the applications corresponding to infrared to visible region

Examining Relationship between Emotional Intelligence and Counterproductive Work Behavior: A Moderated Mediated Model

Despite various attempts to know the relationship between emotional intelligence (EI) and counterproductive work behavior (CWB), the findings are inconsistent and offer a varying degree of associations. The present study examines the underlying mechanism by hypothesizing impression management (IM) as a mediator to address the element of equivocality in the subject matter. Furthermore, it tests the moderating role of self-esteem (SE) on the impression management to counterproductive work behavior relationship. A representative sample of 398 employees was collected from different organizations of Pakistan. The results confirmed the intervening role of impression management between emotional intelligence and counterproductive work behavior. Furthermore, the employees high on self-esteem showed lesser tendencies to involve in counterproductive work behavior. Theoretical and practical implications have also been discussed

Knowledge attitude and practices of undergraduate students regarding first aid measures

OBJECTIVES: To assess knowledge, attitude and practices of first aid measures in undergraduate students of Karachi. METHODS: A cross-sectional study was carried out at six colleges of Karachi, three of which were medical colleges and three non-medical colleges. Knowledge was assessed regarding various emergency situations with the help of a questionnaire. The target population size was 460, based on 50% prevalence and 95% confidence interval. The eventual sample size achieved was 446. RESULTS: A total of 446 students were interviewed. Seventy eight students (17.5%) had formal First Aid (FA) training. The mean number of correct answers of students with FA training was 10.3 (+/- 3.5) as opposed to 8.58 (+/- 4.0) in those without FA training (p \u3c 0.001, 95% CI) with a mean difference of 7.84%. The mean number of correct answers by medical students with FA training was 11.2 (+/- 2.9) as opposed to 7.2 (+/- 3.43) by non-medical students (p \u3c 0.001, 95% CI) with a mean difference of 18.14%. Students having received formal first aid training scored better than those who had not (p \u3c 0.001). CONCLUSION: First aid training programmes should be introduced at school and college level in developing countries to decrease the early mortality and morbidity of accidents and emergencies

Functional Foods and Human Health: An Overview

Functional food is a whole ingredient or a part of food that used as food for specific therapeutic purposes. It is divided into two wide categories: Conventional and modified functional foods. Conventional functional Foods are composed of natural or whole-food ingredients that provide functional substances while modified functional is food or food products in which add additional ingredients for specific health purposes. Plant-based food such as fruits, vegetables, herbs, cereals, nuts and beans contain vitamins, minerals, fiber, omega-3 fatty acids, antioxidants and phenolic compounds that play a functional role in the human body against chronic diseases including cancer, cardiovascular and GIT-related disease. Some other foods or food products like juices, dairy products, fortified eggs and seafood are composed of functional components. Fish contain omega-3 fatty acids (EPA and DHA) that are played a functional role in heart health and brain development

Revamping of Chronic Respiratory Diseases in Low- and Middle-Income Countries

Low- and middle-income countries (LMICs) endure an asymmetrically high burden of worldwide disease and death caused by chronic respiratory diseases (CRDs), i.e., asthma, emphysema, bronchiectasis, and post-tuberculosis lung disease (PTLD). CRDs are firmly related with indigence, infectious diseases, and other non-communicable diseases (NCDs) and add to complex multi-disease with great impact on the lives and livelihood of those affected. The pertinence of CRDs to health and demographic wellbeing is relied upon to increment in the long time ahead, as expectations of life rise and the contending dangers of right on time youth mortality and irresistible infections level. The WHO has distinguished the counteraction and control of NCDs as an earnest improvement issue and crucial for the sustainable development goals (SDSs) by 2030. In this review, we center on CRDs in LMICs. We examine the early life roots of CRDs, challenges in their avoidance, identification and administration in LMICs, and the pathways to resolve for accomplish valid widespread wellbeing inclusion

The impact of immediate breast reconstruction on the time to delivery of adjuvant therapy: the iBRA-2 study

Background: Immediate breast reconstruction (IBR) is routinely offered to improve quality-of-life for women requiring mastectomy, but there are concerns that more complex surgery may delay adjuvant oncological treatments and compromise long-term outcomes. High-quality evidence is lacking. The iBRA-2 study aimed to investigate the impact of IBR on time to adjuvant therapy. Methods: Consecutive women undergoing mastectomy ± IBR for breast cancer July–December, 2016 were included. Patient demographics, operative, oncological and complication data were collected. Time from last definitive cancer surgery to first adjuvant treatment for patients undergoing mastectomy ± IBR were compared and risk factors associated with delays explored. Results: A total of 2540 patients were recruited from 76 centres; 1008 (39.7%) underwent IBR (implant-only [n = 675, 26.6%]; pedicled flaps [n = 105,4.1%] and free-flaps [n = 228, 8.9%]). Complications requiring re-admission or re-operation were significantly more common in patients undergoing IBR than those receiving mastectomy. Adjuvant chemotherapy or radiotherapy was required by 1235 (48.6%) patients. No clinically significant differences were seen in time to adjuvant therapy between patient groups but major complications irrespective of surgery received were significantly associated with treatment delays. Conclusions: IBR does not result in clinically significant delays to adjuvant therapy, but post-operative complications are associated with treatment delays. Strategies to minimise complications, including careful patient selection, are required to improve outcomes for patients

Impact Of Modernization On Religious Institution: A Case Study Of Khyber Pakhtun Khwa, Pakistan

Religion is a unified system of sacred norms, values, beliefs and objects. In any society religion plays an important role in the shaping of the people’s lives, behaviour and interactions. In every aspect of life people consult with their religion and act according to the teachings of religion. At present modernization, globalization and social change are creating very drastic changes in every sphere of life. These changes have both negative and positive impacts on the society. Modernisation is also creating very serious changes in the social institution of religion. In Pakistan, modernization have very severe impact on religion and many sub-sects have been created under the religion of Islam. Each and every sect is claiming that their teachings are true. This phenomenon is crating sectarian violence in Pakistani society. Present study was conducted in the province of “Khyber Pakhtun Khwa, Pakistan”. Pakhtun people follow religion strictly in every segment of life. They sacrifices their lives on the name of Islam. But at present due to modernization, this phenomenon has been changed. Main objective of this study was to analyze the major impacts of modernisation on the religion of Islam in “Pakhtun” culture and society

Diorganotin(IV) Complexes with Monohydrate Disodium Salt of Iminodiacetic Acid: Synthesis, Characterization, Crystal Structure and Biological Activities

Diorganotin(IV) derivatives have been synthesized by the reaction of R 2 SnL 2 (R = n-Bu 1, Ph 2) with monohydrate disodium salt of iminodiacetic acid (Na 2 L) in 1:1 M/L ratio under reflux conditions. The compounds have been characterized by FT-IR, NMR ( 1 H and 13 C) spectoscopy, electron ionization mass spectrometry (EIMS), thermogravimetric analyses (TGA) and single crystal XRD. FTIR data indicates a mono-dentate binding mode of the carboxylic acid group as well as participation of the amino nitrogen and aqua oxygen in coordination with organotin(IV) moieties. NMR data demonstrates a tetra-coordinated environment around tin(IV) in solution. Mass spectrometric and thermogravimetric analyses verify the close similarities between the molecular structures of both complexes. The thermal stability of diphenyltin(IV) derivative (2) was found slightly higher than that of the free ligand (Na 2 L). Single crystal X-ray analysis of the complex 1 have shown a hexa-coordinated geometry around Sn(IV) with trans configuration. There are evidences for the existence of intermolecular hydrogen bonding in the structure of the complexes. The products displayed significant antibacterial and antifungal activities in contrast to the biologically inactive ligand precursor. However, the hemolytic cytoxicity of the complexes was comparatively high than the free ligand

Investigations of novel polymorphs of ZnO for optoelectronic applications

Being a promising candidate in next-generation optoelectronic applications, the study of new polymorphs of zinc oxide (ZnO) is receiving the great attention of researchers. In this article, we explore optoelectronic properties of seven polymorphs of ZnO such as wurtzite type, sphalerite type, germanium phosphide (GeP) type, 5-5 type, nickel arsenide (NiAs) type, β-beryllium oxide (BeO) type and cesium chloride (CsCl) type by using full-potential linearized augmented plane wave plus local orbital (FP-L(APW+lo)) method within Density Functional Theory (DFT). Tran-Blaha modified Becke-Johnson potential (TB-mBJ) along with Generalized Gradient Approximation (GGA) proposed by Perdew-Burke-Ernzerhof (PBE) as exchange-correlation has been used for the calculations of electronic and optical properties of seven polymorphs of ZnO. Our band structure calculations reveal the considered polymorphs of ZnO as wide bandgap semiconductors. The calculated band gap values of wurtzite type, sphalerite type, GeP type, 5-5 type, NiAs type, BeO type and CsCl type polymorphs of ZnO are 2.901 eV, 2.679 eV, 2.648 eV, 3.127 eV, 2.986 eV, 3.040 eV and 1.853 eV respectively. The wurtzite type, sphalerite type, 5-5 type, NiAs type, and BeO type polymorphs of ZnO exhibit direct bandgap while GeP type and CsCl type polymorphs show indirect bandgap. The optical spectra of these polymorphs of ZnO reveal different reflection, plasmon energies, optical absorption, and refractive indices are considerably anisotropic and present different values in the x- and z-direction. The z-component of the reflectivity and absorption spectra was found larger than the x-component in wurtzite type, 5-5 type and NiAs type polymorphs of ZnO, showing that large reflectivity and optical absorption along z-axis than the x-axis in these polymorphs. This study is believed to provide an interesting guideline for the low-cost and non-toxic new polymorphs of ZnO in cutting-edge optoelectronic applications

Effect of Platelet Additive Solution (PAS) on Random Donor Platelet Concentrates

Background: To observe in vitro parameters ofstored platelets in PAS as compared to plasma for 10days.Methods: A comparative study was carried out on42 samples of random donor platelet concentrates(PC). They were divided into two groups of 21samples each and stored in incubator at 22°C. In onegroup plasma was replaced with PAS. Sampling wasdone on day 0, 3, 5, 7, 8, 9 and 10. Bacterial cultureswere carried out. All the samples,which showedcontamination, were excluded from the study.Results: pH and glucose levels were reduced inboth groups but they dropped more rapidly in PCstored in plasma than in PAS (p-value ≤ 0.001).However, the difference in LDH levels between twogroups was not statistically significant. The meanvalues of PO2 were reduced whereas mean values ofPCO2 were increased in both groups, but thesechanges were seen much less in PC stored in PAS (pvalue≤ 0.001). The results showed that difference inall parameters between two groups was highlysignificant (p-value ≤ 0.001) except LDH.Conclusion: All the in vitro parameters were wellpreserved in PC stored in PAS than in plasma