Characterisation of temperature dependent parameters of multi-quantum well (MQW) Ti/Au/n-AlGaAs/n-GaAs/n-AlGaAs Schottky diodes

Forward and reverse current-voltage (IV) of Ti/Au/n-Al0.33Ga0.67As/n-GaAs/n-Al0.33Ga0.67As multi-quantum well (MQW) Schottky diodes were measured over a range of temperatures from 20 to 400 K by a step of 20 K. The Schottky diodes parameters were then extracted from these characteristics. The Cheung method is used for this purpose, assuming a thermionic conduction mechanism. The extracted ideality factor decrease with increasing temperatures. But their values at low temperatures were found to be unrealistic. In order to explain this uncertainty, three assumptions were explored. Firstly an assumed inhomogeneous barrier height gave better parameters especially the Richardson constant but the ideality factor is still unrealistic at low temperatures. Secondly, by using numerical simulation, it was demonstrated that defects including interface states are not responsible for the apparent unrealistic Schottky diode parameters. The third assumption is the tunnelling mechanism through the barrier in the low temperature range. At these lower temperatures, the tunnelling mechanism was more suitable to explain the extracted parameters values

Prevalence and risk factors of Hepatitis B among pregnant women.

Introduction: Globally Hep C virus (HBV) a public health problem account for 2 billion infection and 400 million of them were chronically infected1,2,3. In Pakistan prevalence among general population is 4.3 % with carrier rate 3-5% (7-9 million) 4.  The prevalence of HBV among pregnant women 5% (range 0.6% to >20%) worldwide, leading mother to child transmission causing fetal and neonatal hepatitis, attributed for 30% to 50% of chronic carriers. Methodology: A cross-sectional study was conducted among randomly selected 140pregnantwomen attended the antenatal clinic of the District hospital of Rahim-Yar-Khan in June-July 2013. Rapid diagnostic tests kits were used to access for HB surface antigen (HBsAg).  A face to face interview was carried out by using structured pre-tested questionnaire to obtain demographic and other information. Results: 16(9.3%) out of 140 pregnant women were found to be positive for HBsAg, higher risk age group was 20-29 years 10(62.5%) , 16(100%) out of 16 infected women and 6(4.83%) out of 124 non-infected women had Negative history of HBV in Husband. Blood transfusion in last pregnancy was 14(87.5%) out of 16 infected women and 52(41.93%) out of 124 non-infected women. 10(62.5%) out of 16 infected women and 5(4.03%) out of 124 non-infected women has passed through dental procedures. Therefore, negative history of HBV in Husband, blood transfusion and dental procedures in last pregnancy were the most prevalent risk factors among infected women. Among the total 124, 76(61.29%) were vaccinated against HBV, while 0(0%) out of 16 infected women were not vaccinated. Conclusion: Prevalence of the HBV among pregnant women in Rahim-Yar-Khan is of intermediate endemicity (11.4%). Past history of blood transfusion and HBV infected Husband was the most prevalent risk factor. Health education regarding risk factors, preventive measures should be given to pregnant women with the involvement of Lady Health Worker and mass media. Free screening and immunization of pregnant women should be incorporated in antenatal and postnatal program of hospital

Pattern of acute diarrhea and its management among children at DHQ Hospital, Attock city from July-August 2014.

Introduction: Acute diarrhea is the 2nd most common cause of death among children under 5 years age countrywide. It is the passage of watery or loose stools 3 or more times in 24 hours and lasting less than 14 days. Methodology: This Comparative study was carried out at DHQ Hospital Attock City from July-August 2014 by using a close ended questionnaire. Results: From July 2014-August 2014, a total of 40 children having acute diarrhea were hospitalized in the DHQ Hospital Pediatric ward. There were more males n=24(60%) then females n=16 (40%) and the male to female ratio was 1.5: 1. 50% of the patients presented in 2nd half of 1st year.  n=32 (80%) children presented with 4 days of illness. All patients had passed 8-10 stools per day. One had passed 15-20 stools per day. n=9 (22.5%) child pass small amount of blood/ mucous in stools. Exclusive breastfeeding was reported in n=8 (20%) of the patients. n=18 (45%) children did not show any signs of dehydration, n=15 (37.5%) showed some dehydration and n=7 (17.5%) showed severe dehydration. Symptoms associated with diarrhea were fever n=31 (77.5%), cough n=17 (17.5%), vomiting n=8 (20%), oral thrush n=1 (2.5%). Blood CP n=39 (97.5%), ESR, Stool Examination n=31 (77.5%), X-Ray Chest n=8 (20%) were the investigations done in children. ORS/OEM use rate was 40 (100%) while rate of antibiotic (ceftriaxone) was n=7 (17.5%), n=33 (82.5%) received  Zinc Sulphate in syrup form, n=31 (77.5%) received Syrup Paracetamol. Conclusion: Diarrhea is a common illness among children under 1-year age. Fever is the most common associated symptom with diarrhea. Parenteral diarrhea due to abdominal infections is also predominant condition. Key Words: Diarrhea, Abdominal infections, Oral rehydration salt

Distribution of Extended-spectrum β-lactamase and Metallo-β-lactamase-producing Pseudomonas aeruginosa in Tertiary Care Hospitals of Lahore, Pakistan

Background: Pseudomonas aeruginosa (P. aeruginosa) is an important bacterial pathogen most frequently associated with nosocomial infections, especially in immuno-compromised patients. Early detection of these life threatening, β-lactamase producing bacteria is essential for infection control and to prevent their dissemination. The aim of our study was to detect the presence of Extended-Spectrum β-Lactamase (ESBL) and Metallo-β-Lactamase (MBL) strains of Pseudomonas aeruginosa.Material and Methods: Eighty-eight identified strains of P. aeruginosa were collected from Chughtai Laboratories, Combined Military Hospital and Children Hospital, Lahore. These strains were sub-cultured and after confirming the cultural characteristics by Gram staining and colony morphology, manual biochemical identification was done. Susceptibility to various antibiotics and production of extended-spectrum β-lactamases (ESBLs) and metallo-β-lactamases (MBLs) were determined using modified Kirby Bauer disk diffusion method, double disk synergy test, combined disk synergy test (CDST) and inhibitor-potentiated disk diffusion test (IPD) respectively.Results: Out of eighty-eight strains tested, three were ESBL producers (3.4%) and eleven strains (12.5%) were found to be resistant to carbapenems. Of these, eight were MBL producers (72.7%). All these β-lactamase producing strains (14 strains) were multidrug-resistant (MDR). Piperacillin and piperacillin/tazobactam proved to be the most effective antibiotics in both types of β-lactamase producing strains.Conclusion: Our study shows noticeable emergence of β-lactamases (ESBLs & MBLs) in P. aeruginosa. All of these strains were MDR. It reveals a correlation of these β-lactamases with multidrug resistant genes

ESBL determination and antibacterial drug resistance pattern of Klebsiella Pneumoniae amongst patients at PIMS Islamabad

Background: A number of life threatening infections due to various bacterial pathogens are major cause  of death in Pakistan. In a situation like the other developing countries, there is a general increase in the  drug resistance due to the irrational use of the antibiotics. The present study was carried out to evaluate the prevalence and development of resistance in Klebsiella pneumoniae against commonly used antibiotics.Methods and Materials: A total of 200 samples from different wards of the hospitals were received by the pathology laboratory of Pakistan Institute of Medical Sciences, Islamabad, which comprised of urine  65, blood 50 and other miscellaneous samples from various sources. Klebsiella pneumoniae was isolated and characterized using morphological, cultural, and biochemical methods and were further confirmed by using commercially available API 20E kit. The isolates were subjected to culture sensitivity test using  Kirby Bauer disc diffusion method.Results: The organism was found to be the most prevalent Gram-negative bacilli. K. pneumoniae showed  highest resistance against coamoxiclav and cephalosporins.Conclusion: The study revealed that ESBL producing strains were resistant to most of the beta-lactam antibiotics. This trend therefore has become a significant problem and can be controlled with continued surveillance or monitoring for rationally improved antibiotics usage, in order to prevent the drug resistance and re-emergence of infection.Key words: Klebsiella pneumoniae, ESBL (Extended-spectrum beta-lactamase), API (Analytical Profile Index

Hybrid exponentially weighted moving average control chart for mean by using different ranked set sampling schemes

In this paper different schemes of ranked set sampling (RSS) are used to design a new hybrid exponentially weighted moving average (HEWMA) control chart having more sensitivity to small and moderate shifts.The  suggested control chart  dominates classical exponentially weighted moving average (EWMA) control chart, EWMA based on RSS and HEWMA control chart using simple random sampling (SRS). The ARLs and SDRLs based on Monte Carlo simulations are used as an evaluation measure for the sensitivity of proposed control chart which shows that the HEWMA using RSS schemes significantly increases the performance of control chart. An example containing real data is also given to further explain the application

blaOXA, blaSHV-, and blaTEM- extended-spectrum β-lactamases in Gram-negative strains from burn patients in Lahore, Pakistan

Introduction: Gram-negative bacterial pathogens are associated with complications of post-burn infections that showed significant association with different genotypic variants of extended-spectrum β-lactamases. In this study, we aimed to determine the distribution of ESBL gene variants among bacterial pathogens from post-burn infections. Methodology: Cephalosporin-resistant isolates were collected from Jinnah Burn and Reconstructive Surgery Centre, Lahore. Phenotypic testing: double-disk synergy test, combination disk test, multiplex PCR for blaOXA, blaTEM, and blaSHV genes were performed. Results: Of the 53.5% cephalosporin-resistant isolates, 50.7% were community-acquired and 49.3% were nosocomial pathogens. Seventy-two percent of post-burn infections were found in males (p-value = 0.92, OR = 1.04). The age of burn victims ranged from 4 to 85 years (mean = 28.9, SD = 15.6). Pseudomonas aeruginosa was most predominant at a rate of 49%. There were 83.3% multidrug-resistant isolates, which showed susceptibility to meropenem, imipenem, and amikacin in 28.7%, 25.3%, and 26% respectively. In phenotypic tests 16% ESBLs detected by the DDST and 14% confirmed by the CDT. Molecular detection proved effective for the detection of 79.7% blaTEM, 37.7% blaOXA, and 18.8% blaSHV isolates. blaTEM genes were confirmed in 18.1% CDT-positive isolates, with 62.6% diagnostic accuracy (95% CI = 54.7-70) and 88% specificity (95% CI = 80.4-93.4). Conclusions: The antimicrobial resistance associated with the ESBL-producing Pseudomonas spp. and Enterobacteriaceae is becoming a challenge for the treatment and survival of burn patients. The high rate blaTEM, blaOXA, and blaSHV genes confirm the need to improve the management of burn patients in order to prevent post-burn infections

Surface-Functionalized Magnetic Silica-Malachite Tricomposite (Fe-M-Si tricomposite): A Promising Adsorbent for the Removal of Cypermethrin

This study assessed the efficacy of adsorption for eliminating the agricultural pesticide cypermethrin (CP) from wastewater using various adsorbents: silica, malachite, and magnetite. Magnetic nanocomposites (NCs) (with varying amounts of Fe3O4 0.1, 0.25, 0.5, 1.0, and 1.5 wt/wt %) were synthesized, including Fe3O4 nanoparticles (NPs), bicomposites, and tricomposites, calcined at 300 and 500 °C, and then tested for CP removal. The study was conducted in two phases, with the objective of initially assessing how effectively each individual NP performed and then evaluating how effectively the NCs performed when used for the adsorption of CP. Notably, the Fe3O4–malachite combination exhibited superior CP removal, with the 0.25-Fe–M NC achieving the highest adsorption at 635.4 mg/g. This success was attributed to the large surface area, magnetic properties of Fe3O4, and adsorption capabilities of malachite. The Brunauer–Emmett–Teller (BET) isotherm analysis indicated that the NCs had potential applications in adsorption and separation processes. The scanning electron microscopy and transmission electron microscopy revealed the spherical, irregular shaped morphology of the synthesized NPs and NCs. However, the X-ray diffraction (XRD) pattern of surface functionalized materials such as surface functionalized malachite [Cu2CO3(OH)2] with Fe3O4 and SiO2 may be complicated by the specific functionalization method used and the relative amounts and crystallographic orientations of each component. Therefore, careful interpretation and analysis of the XRD pattern, along with other techniques, are necessary for accurate identification and characterization of the functionalized material. The originality of this study lies in its comprehensive investigation of several adsorbents and NCs for CP removal at neutral pH. The innovation stems from the synergistic action of Fe3O4 and malachite, which results in improved CP removal due to their combined surface properties and magnetic characteristics. The application of magnetic NCs in adsorption and separation, as validated by BET isotherm analysis, highlights the potential breakthrough in addressing pesticide contamination

Synthesis of graphene oxide (GO) and reduced graphene oxide (rGO) and their application as nano-fillers to improve the physical and mechanical properties of medium density fiberboard

Graphene is an advanced material in the carbon group and offers greater mechanical, electrical, structural, and optical properties. Graphene oxide (GO) and reduced graphene oxide (rGO) nanoparticles were synthesized and characterized and their special effects on enhancing the physio-mechanical characteristics of medium density fiberboard (MDF) were assessed. GO and rGO nanoparticles were added to urea formaldehyde (UF) resin at different weight percentages (1.0, 2.0, and 3.0 wt%) during the dosing process. To manufacture the MDF, nanofillers were created by sonication and combination with natural wood fibers. To observe the behavior of nanoparticles in the nanofillers, microstructure characterizations were conducted. The manufactured nano MDF samples underwent physical and mechanical testing. The incorporation of GO and rGO nanoparticles into UF resin led to significant improvements in the physical and mechanical properties of the MDF. The addition of GO and rGO nanoparticles at different weight percentages (1.0, 2.0, and 3.0 wt%) resulted in a range of improvements in thickness swelling (up to 53.3% and 35.2% for GO and rGO nanoparticles, respectively), water absorption (up to 23.3% and 63.15%, respectively), and thermal conductivity (up to 42.16% and 27.7%, respectively). Additionally, the internal bond and rupture modulus of the MDF was enhanced by 59.0% and 70.0%, respectively, for GO and 41.4% and 48.5% for rGO. The highest value of the modulus of rupture (MoR) was observed at a concentration of 3.0% of rGO nanoparticles (44.7 MPa). The findings also showed that thickness swelling (Ts) and water absorption (WA) exhibited directly proportional relationships for 3.0% GO and rGO. These results suggested that incorporating GO and rGO nanoparticles into UF resin can significantly improve the physical and mechanical properties of nano MDF.publishedVersio

Bone Mineral Density in Children with Congenital Adrenal Hyperplasia

Background: Treatment in all forms of Congenital Adrenal Hyperplasia (CAH) includes lifelong replacement of steroids. Steroids have an impact on bone health in multiple ways and are known to cause osteoporosis when given in high doses or for a longer duration. Objective: To evaluate bone mineral density (BMD), using dual-energy X-ray absorptiometry (DEXA) scan in children with CAH taking long-term steroids presenting in the pediatric endocrinology ward of National Institute of Child Health, (NICH) Karachi, Pakistan. Materials and Methods: This cross-sectional study was performed at the Department of Pediatric Endocrinology, National Institute of Child Health, Karachi from October 2021 to July 2022. A total of 47 diagnosed cases of CAH taking steroids for more than 5 years were enrolled. Assessment of BMD was done using a DEXA scan. Lumbar spine BMD was done and Z-score was modified for height for age z-score. The dose of steroids and duration was calculated. Results: Out of 47 patients, low BMD was observed in 8 (17.02%) patients. Individuals with low BMD had significantly higher median duration, (p=0.017), dose (p=0.003), and median alkaline phosphate level (p=0.036),) but low median BMD value (p=0.009) and z score (p<0.001) than normal BMD individuals. Although median bone age (p=0.009) was appropriate for chronologic age in low BMD patients. A moderate negative significant correlation was observed between z score and age (rho=-0.319, p=0.029), z-score and duration of steroid treatment (rho=-0.364, p=0.012), z score and alkaline phosphate (rho=-0.466, p=0.001), z score and bone age (rho=-0.378, p=0.009). Conclusion: Low BMD was observed in 17% of children on the DEXA scan. Moreover, these individuals had significantly higher median average duration and dose of hydrocortisone