Dimethyl (1,1′-binaphthyl-2,2′-di­oxy)diacetate

The two naphthyl fused-ring systems in the title compound, C22H26O6, are aligned at 86.7 (1)°. Weak inter­molecular C—H⋯O hydrogen bonding is present in the crystal structure

Di-tert-butyl (1,1′-binaphthyl-2,2′-di­oxy)diacetate

In the crystal structure of the title compound, C32H34O6, the mol­ecule is located on a twofold rotation axis. The two naphthyl fused-ring systems are aligned at 72.6 (1)°. Weak intermolecular C—H⋯O hydrogen bonding is present in the crystal structure

Ethambutol Induced Ocular Toxicity in Patients Receiving “Directly Observed Treatment Short-Course” Therapy

Background: To determine the frequency of Ocular toxicity due to Ethambutol in Category-1 patients after receiving DOTS therapy. Methods: Category-1 tuberculosis patients of 15-60 years (both gender) with normal ocular parameters on ophthalmological assessment at time of initiation of DOTS therapy were included in the study. A total of 242 eyes (121 patients) were studied for any change in the vision or occurrence of any other ocular symptom while on the Ethambutol treatment. Each patient was followed up for Ethambutol compliance status at the completion of one month and again at two months of treatment, all the ophthalmological assessments for ocular toxicity were repeated for every selected patient. Category-2 patients with sputum smear positive who have relapsed, who have treatment failure or who are receiving treatment after treatment interruption were excluded from the study. The patient’s information was gathered on a specifically designed proforma. The information on the proforma was filled by the researchers themselves. Results: Out of 121 patients (242 eyes), 64 (52.9%) were males and 57 (47.1%) were females. There was no sign of ocular toxicity after a month period. However, after second month ocular toxicity was developed in 02 (1.65%) of the patients. Besides, decrease in visual acuity, color vision abnormalities, decrease in contrast sensitivity, and optic disc abnormalities were also observed in these 02 patients. Conclusion: There is a possibility of the occurrence of ocular toxicity when the Ethambutol is taken by the tuberculosis patients. Thus, the early identification of ocular symptoms and signs is vital to avoid unnecessary delay in diagnosis and probable irreversible visual loss

Geochemical control on spatial variability of fluoride concentrations in groundwater from rural areas of Gujrat in Punjab, Pakistan

Spatial variability and geochemical factors controlling fluoride (F−) concentrations were evaluated in five villages of subdistrict Gujrat in Pakistan. Groundwater samples (n = 70) were collected along the River Chenab and examined for F− concentrations. The average F−concentrations in groundwater of village Chhani Nikoani (1.8 mg/L) and Dhool Khurd (2.2 mg/L) were crossing the World Health Organization (WHO) permissible limit of 1.5 mg/L, while village Kalra Khasa, Ghazi Chak and Kula Chor were below the WHO guidelines. About 64 % of the samples contain fluoride concentrations that exceed the 1.5 mg/L drinking water standard set by WHO. Spatially F− concentrations in groundwater increased as moving away from the River Chenab because more residence time for water–rock interaction was available. High F− concentrations were associated with high electric conductivity (EC), total dissolved solids (TDS), pH and Na+ values. The overall groundwater quality is controlled by silicate mineral weathering and less by evaporation. Fluoride originates from anion exchange (OH− for F−) on clays and weathered micas under high pH conditions. High fluoride levels are associated with NaCl- and NaHCO3-type water produced by calcite precipitation and/or base ion exchange. The groundwater with higher fluoride concentrations is accompanied by lower Ca+2levels. This study enhances our understanding on geochemical behavior of F and highlights the importance of spatial variability on F release in aquifers of Punjab in Pakistan, as well as in other countries of Asia region

Student’s Perception of Computer Based Assessment Environment in an Undergraduate Medical College

Background: It is emphasized in medical education that assessment drives learning. In 2020, during the first COVID-19 lockdown, University College of Medicine and Dentistry made a shift towards Computer Based Assessments (CBAs) in order to facilitate learning. Objective: To determine undergraduate medical student’s perception for computer based assessment environment in medical school Methods: The cross-sectional descriptive study was conducted at the University of Lahore, Pakistan, from May 2022 to September 2022, and included undergraduate medical students who were requested to complete the Assessment Environment Questionnaire. Students' individual perception scores were calculated and the means of individual domains and global scores were compared in different academic years. SPSS version 23 was used for statistical analysis.   Results: Of 574 participants, 20% of the participants were from 1st year, 20.7% were from second year, 20% from 3rd year, 19.9% from 4thyear and 19.3% from final year. Generally, the students perceived their assessment environment positive resulting in a global mean score of 67.6±13.7 out of the maximum 80. First year students scored significantly higher (P <0.01) compared to other years. Conclusion: The students' perception for computer based assessment environment was positiv

Factors Controlling the Spatial Distribution and Temporal Trend of Nationwide Groundwater Quality in Korea

Factors controlling the spatial distribution and temporal trend of groundwater quality at a national scale are important to investigate for sustaining livelihood and ecological balance. This study evaluated groundwater quality data for 12 parameters (n = 6405 for each parameter), collected from 97 groundwater monitoring stations (=289 monitoring wells) for ten years. Spatial distribution of groundwater quality parameters varied through the regional scale. Six parameters: T, EC, Ca2+, Mg2+, HCO3&minus;, and Cl&minus; were having dominant increasing trend, remaining pH, Eh, Na+, K+, SO42&minus;, and NO3&minus; showed a dominant decreasing trend over time. Among land use types, the upland fields had the highest mean of groundwater NO3&minus; (22.2 mg/L), confirming plenty of application of fertilizers (5&ndash;10 kg/a more than standard) to upland fields. Means of groundwater Cl&minus; and Na+ (705.3 and 298.4 mg/L, respectively) in the residential areas are greater than those in other land use types by 408&ndash;685.9, 154.3&ndash;274.2 mg/L, respectively. Agricultural activities were the main controlling factor of groundwater NO3&minus; contamination in rural areas, domestic activities were responsible for groundwater Cl&minus; and Na+ in urban areas, and seawater intrusion was controlling groundwater Cl&minus; in coastal areas (within 10 km from sea). Groundwater hydrochemistry was controlled by the mechanism of geogenic rock and evaporation dominance. The rock dominance mechanism indicated that groundwater was interacting with rocks and resulted in groundwater chemistry. The findings of this study showed that groundwater was mainly contaminated by anthropogenic factors in some rural and residential areas. Effective measures by government authorities are needed to improve the groundwater quality