Radical Chemistry in a Femtosecond Laser Plasma: Photochemical Reduction of Ag+ in Liquid Ammonia Solution

Plasmas with dense concentrations of reactive species such as hydrated electrons and hydroxyl radicals are generated from focusing intense femtosecond laser pulses into aqueous media. These radical species can reduce metal ions such as Au3+ to form metal nanoparticles (NPs). However, the formation of H2O2 by the recombination of hydroxyl radicals inhibits the reduction of Ag+ through back-oxidation. This work has explored the control of hydroxyl radical chemistry in a femtosecond laser-generated plasma through the addition of liquid ammonia. The irradiation of liquid ammonia solutions resulted in a reaction between NH3 and OH·, forming peroxynitrite and ONOO−, and significantly reducing the amount of H2O2 generated. Varying the liquid ammonia concentration controlled the Ag+ reduction rate, forming 12.7 ± 4.9 nm silver nanoparticles at the optimal ammonia concentration. The photochemical mechanisms underlying peroxynitrite formation and Ag+ reduction are discussed

Early Chronotype Favors Appetite and Reduced Later Day Caloric Intake Among Adults with Metabolic Syndrome

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Hookworm infestation as a cause of melena and severe anaemia in farmer

Abstract Hookworm infections remain a major cause of morbidity in the developing world. Prevalence is highest in agricultural areas, where use of waste water for irrigation and poor hygiene increases infection rates among farmers. Infections present with gastrointestinal symptoms and chronic anaemia, and there are usually no signs of overt blood loss.The following report describes a case of melena in a middle-aged farmer, where the diagnosis of hookworm infestation was delayed due to the unusual presentation. The patient underwent multiple blood transfusions before referral to the Aga Khan University Hospital (AKUH), Karachi and was managed conservatively with mebendazole at our hospital after exclusion of other possible causes of gastrointestinal bleeding. This case highlights the importance of considering hookworm infestations as a cause of melena in the older age group, where other critical differentials such as peptic ulcer disease and occult malignancy may result in delay in initiation of treatment and a significant financial burden on the patient

Teachers’ perceptions and practices of written feedback in higher education.

This mixed-methods research aimed to understand the practices and perceptions of teachers regarding writtenfeedback. For this purpose, a survey was administered to 150 teachers forming a non-probability sample, who wereworking in various universities in Karachi. The disciplines chosen for the study included nursing, applied linguistics,medicine and education departments in institutes of higher education situated in Karachi. Before sampling, initialscreening was done to obtain a list of institutes which provide written feedback on students’ assignments. Twohomogenous groups of teachers by discipline (nursing and education) were then selected for focus group discussions.It was found that most teachers consider written feedback an important tool for guiding and helping students improvetheir work. In fact, they consider written feedback as important as verbal feedback. Teachers also recognized theimportance of discussing the written feedback with the students but they rarely did so because of time constraints.Most teachers preferred to directly fix students’ errors instead of providing feedback to enable them to correct thoseerrors by themselves. While less than half of the participants used a checklist for grading, others used annotation.Several factors were found to have a great influence on the amount and quality of feedback. The most significantfactor was whether teachers had formal training in providing feedback. Only 17% of the participants in this study hadproper training to give written feedback. They also identified several environmental and personal factors that had animpact on their feedback practices including time, the relationship between the teacher and individual students, and,most importantly, the policies and culture of the institutes

A comparative study on efficacy of metoprolol and ivabradine in acute ST elevation myocardial infarction patients

Background: The ST-elevation myocardial infarction (STEMI), a fatal disease, is rapidly extending in patients, worldwide. Therefore, proper and timely diagnosis followed by appropriate management becomes necessary. The study aimed to compare the effectiveness of metoprolol and ivabradine in acute STEMI patients.Methods: This was an observational, comparative, in-hospital study carried out in patients admitted in the in-patient cardiac department, intensive cardiac care unit of a tertiary care centre in India. Total 60 patients diagnosed with acute ST-elevation MI were included in the study and were equally divided into two groups. Group 1 involved patients who were given metoprolol for treatment and group 2 involved patients who were given ivabradine. The patients were assessed in terms of heart rate, NYHA class, and ejection fraction. Follow-up of 30 days was taken in all patients.Results: Ivabradine reduced mean heart rate from 85.57 bpm at baseline to 78.23 bpm. Heart rate in the metoprolol group was reduced from 81.93 bpm to 76.47 bpm over the same time period. Metoprolol and ivabradine showed significant improvement in the ejection fraction volume during the in-hospitalization stay. Ivabradine showed a better improvement in ejection fraction when compared to metoprolol but the difference was not found to be statistically significant. Higher mortality was assessed in ivabradine group compared to metoprolol.Conclusions: The study gives the gold standard efficacy and mortality benefit of metoprolol, although ivabradine on the other hand gave better responses in heart rate reduction and improvements in ejection fraction

Socio-demographic profile of poisoning in children admitted to a tertiary hospital

Background: Childhood poisoning is a significant public health problem and is very important cause of mortality and morbidityin children. The offending substances used vary from place to place. The pattern of poisoning has been changing with new hazardsconstantly appearing due to the introduction of new drugs and chemicals. Childhood poisoning is usually accidental makingpoisoning a preventable problem. Objectives: To determine the socio-demographic and clinical profile and outcome of childhoodpoisoning in a tertiary care hospital. Materials and Methods: This prospective study was done over a period of 2-year in a tertiarycare hospital. We studied children <15 years of age who were admitted to our hospital with a history of poisoning. Children withhistory of food poisoning, snake bite, scorpion sting, and insect bites were excluded from the study. The demographic profile ofpatients, various substances of poisoning, mode of poisoning, and outcome of admitted children with poisoning were studied.Results: Among 200 children admitted with the history of poisoning, 126 (63%) were boys and 74 (37%) were girls. The majorityof the poisoning were accidental in nature and found to be common in the age group of 1-5 years, children from rural areas, and areof lower socio-economic status. Kerosene poisoning was the most common (35%) agent followed by organophosphorus poisoning(11%). 4 children died due to various complications of poisoning. Conclusion: Common household products were found to be themain source of poisoning in younger age groups from rural background, and the majority was accidental in nature. Educationalprograms toward creating awareness among public are necessary to reduce the incidence of poisoning in children

A simplified and cost-effective enrichment protocol for the isolation of Campylobacter spp. from retail broiler meat without microaerobic incubation

<p>Abstract</p> <p>Background</p> <p>To simplify the methodology for the isolation of <it>Campylobacter </it>spp. from retail broiler meat, we evaluated 108 samples (breasts and thighs) using an unpaired sample design. The enrichment broths were incubated under aerobic conditions (subsamples A) and for comparison under microaerobic conditions (subsamples M) as recommended by current reference protocols. Sensors were used to measure the dissolved oxygen (DO) in the broth and the percentage of oxygen (O₂) in the head space of the bags used for enrichment. <it>Campylobacter </it>isolates were identified with multiplex PCR assays and typed using pulsed-field gel electrophoresis (PFGE). Ribosomal intergenic spacer analyses (RISA) and denaturing gradient gel electrophoresis (DGGE) were used to study the bacterial communities of subsamples M and A after 48 h enrichment.</p> <p>Results</p> <p>The number of <it>Campylobacter </it>positive subsamples were similar for A and M when all samples were combined (<it>P </it>= 0.81) and when samples were analyzed by product (breast: <it>P </it>= 0.75; thigh: <it>P </it>= 1.00). Oxygen sensors showed that DO values in the broth were around 6 ppm and O₂values in the head space were 14-16% throughout incubation. PFGE demonstrated high genomic similarity of isolates in the majority of the samples in which isolates were obtained from subsamples A and M. RISA and DGGE results showed a large variability in the bacterial populations that could be attributed to sample-to-sample variations and not enrichment conditions (aerobic or microaerobic). These data also suggested that current sampling protocols are not optimized to determine the true number of <it>Campylobacter </it>positive samples in retail boiler meat.</p> <p>Conclusions</p> <p>Decreased DO in enrichment broths is naturally achieved. This simplified, cost-effective enrichment protocol with aerobic incubation could be incorporated into reference methods for the isolation of <it>Campylobacter </it>spp. from retail broiler meat.</p