Dynamic light scattering and zeta-potential as a tool for understanding the mechanism of pesticides binding toward individual components of transition metal nanoparticles and graphene oxide hybrids.

Pesticides present in their commercial formulations are studied for their preferable binding toward carbon-based graphene oxide (GO) or transition metal nanoparticles (Fe, Co, Ni, and Cu), present as hybrids. This simple study also reveals the mechanism of interaction of few selected different classes of pesticides, namely, λ-cyhalothrin, imidacloprid, and metsulfuron-methyl toward these hybrids. Individually, to study this comparative binding when hybrids are not used, the understanding of preferred binding toward any of these selected compounds could be challenging, costly, and time-consuming. Dynamic light scattering (DLS) is used to study the changes observed for hydrodynamic radius and zeta potential for the stability of the resulting products. This simple method can also be extended to identify the binding mechanism for other diverse set of combinations. These studies are supported by binding of GO with nanoparticles in batch adsorption and the best fit using Langmuir and Freundlich isotherms is presented. Moreover, pesticide adsorption toward GO-nanoparticle composites is also evidenced.

Endoscopic Findings and Their Association With Gender, Age and Duration of Symptoms in Patients With Dysphagia.

Introduction Dysphagia is highly prevalent in patients with a history of recurrent acid peptic disease. Endoscopy is the mainstay of diagnostic workup of these patients to reach underlying cause and appropriate subsequent treatment. The objective of the study was to determine the frequency of various types of endoscopic findings in patients with dysphagia and the association of these findings with gender, age and duration of symptoms. Methods This cross-sectional study was carried out in the Department of Gastroenterology of a tertiary care hospital in Rawalpindi, Pakistan. A total of 137 patients who presented with a history of dysphagia for at least two weeks were enrolled in the study. Duration of symptoms was noted, and all patients underwent upper gastrointestinal endoscopy to find out the cause of dysphagia. Tissue biopsies were obtained, and further histopathological examination was performed to correlate the findings with symptoms of dysphagia.  Results A total of 137 patients were enrolled for six months. The mean age of the patients was 56.9 ± 17.44 years, and the mean duration of symptoms was 15.96 ± 12.31 weeks. There were 65 (47.4%) males and 72 (52.6%) females in the study. Majority of them, 123 (89.8%), presented with a short duration of symptoms that varied between 2-24 weeks and were mainly middle-aged (31-60 years) and old-aged (61-80 years). The most commonly observed endoscopic findings were esophageal stricture in 25 (18.2%), achalasia cardia in 20 (14.6%), esophageal mass in 12 (8.8%) and reflux esophagitis in 7 (5%) patients. No association was seen between age, gender and duration of symptoms and findings on the endoscopy. Conclusion Dysphagia is associated with many endoscopic findings that are not related to demographic variables and must be evaluated earlier to reduce further morbidity and mortality.