Construction of a uniform zeolitic imidazole framework (ZIF-8) nanocrystal through a wet chemical route towards supercapacitor application.

Exploring larger surface area electrode materials is crucial for the development of an efficient supercapacitors (SCs) with superior electrochemical performance. Herein, a cost-effective strategy was adopted to synthesize a series of ZIF8 nanocrystals, and their size effect as a function of surface area was also examined. The resultant ZIF8-4 nanocrystal exhibits a uniform hexagonal structure with a large surface area (2800 m2 g-1) and nanometre size while maintaining a yield as high as 78%. The SCs performance was explored by employing different aqueous electrolytes (0.5 M H2SO4 and 1 M KOH) in a three-electrode set-up. The SC performance using a basic electrolyte (1 M KOH) was superior owing to the high ionic mobility of K+. The optimized ZIF8-4 nanocrystal electrode showed a faradaic reaction with a highest capacitance of 1420 F g-1 at 1 A g-1 of current density compared to other as-prepared electrodes in the three-electrode assembly. In addition, the resultant ZIF8-4 was embedded into a symmetric supercapacitor (SSC), and the device offered 350 F g-1 of capacitance with a maximum energy and power density of 43.7 W h kg-1 and 900 W kg-1 at 1 A g-1 of current density, respectively. To determine the practical viewpoint and real-world applications of the ZIF8-4 SSC device, 7000 GCD cycles were performed at 10 A g-1 of current density. Significantly, the device exhibited a cycling stability around 90% compared to the initial capacitance. Therefore, these findings provide a pathway for constructing large surface area ZIF8-based electrodes for high-value-added energy storage applications, particularly supercapacitors.

Tunning the Zeolitic Imidazole Framework (ZIF8) through the Wet Chemical Route for the Hydrogen Evolution Reaction.

Utilizing zeolitic imidazolate frameworks (ZIFs) poses a significant challenge that demands a facile synthesis method to produce uniform and nanometer-scale materials with high surface areas while achieving high yields. Herein, we demonstrate a facile and cost-effective strategy to systematically produce ZIF8 nanocrystals. Typically, ZIF8 nanocrystal synthesis involves a wet chemical route. As the reaction time decreased (150, 120, and 90 min), the size of the ZIF8 crystals decreased with uniform morphology, and productivity reached as high as 89%. The composition of the product was confirmed through XRD, FE-SEM, TEM, EDS, and Raman spectroscopy. The ZIF8 synthesized with different reaction time was finally employed for catalyzing the electrochemical hydrogen evaluation reaction (HER). The optimized ZIF8-3 obtained at 90 min of reaction time exhibited a superior catalytic action on the HER in alkaline medium, along with a remarkably long-term stability for 24 h compared with the other ZIF8 nanocrystals obtained at different reaction times. Specifically, the optimized ZIF8-3 sample revealed an HER overpotential of 172 mV and a Tafel slope of 104.15 mV·dec-1. This finding, thus, demonstrates ZIF8 as a promising electrocatalyst for the production of high-value-added green and sustainable hydrogen energy.

A nationwide survey on the management of the COVID-19 pandemic and respiratory disease in South Korea.

Background: This study aimed to explore individual prevalence of respiratory symptoms and to describe the Korean population's treatment approaches, preventive health behaviors, and mental health conditions during the pandemic. Methods: We analyzed responses from an online nationwide survey, conducted between February 2021 to May 2021, about people's experiences during the pandemic. Statistical analysis was also performed to see if there were any significant differences in treatment and prevention strategies between different groups of respondents (between those had respiratory symptoms, compared with those who did not, and between those tested positive for COVID-19, compared with those who did not). Results: A total of 2,177 survey respondents completed the survey and, of these, only 142 had experienced symptoms. The most frequently reported respiratory infections related symptoms were runny or blocked nose (47.6%), cough (45.5%), fever (44.1%), sore throat (42.0%), and fatigue (30.1%). More than half of the respondents (53.1%) used complementary and alternative medicine (CAM) approaches as means of preventive measures. In terms of preventive behaviors, the more emphasized behaviors were mask-wearing (58.9%) and hand-washing after coming home (42.7%). The majority of the respondents (64.9%) did not show signs of mental health issues. Conclusion: In South Korea, conventional medicine was mainly used for COVID-19 treatment whereas CAM was commonly used as preventive measures. COVID-19 was also found to have less impact on the general population's mental health. The findings of this study may shed light on how the pandemic impacted the general population.

Maca (Lepidium meyenii Walp.) on semen quality parameters: A systematic review and meta-analysis.

Background: This study aimed to examine the evidence for the effect of Lepidium meyenii Walp. [Brassicaceae] (L. meyenii W.), known as maca, on improving semen quality. Methods: Nine databases were searched for randomized controlled trials (RCTs) that examined the parameters for improvements in semen quality, regardless of the type of L. meyenii W. The risk of bias (ROB) among the studies was evaluated according to the Cochrane ROB tool. Results: Five RCTs met all of the inclusion criteria. Three RCTs showed mixed efficacy of maca in improving semen quality parameters, including sperm concentration and sperm motility, in men experiencing infertility. The meta-analysis also failed to show the efficacy of maca in increasing the sperm concentration compared to the placebo (weighted mean difference, 2.22, 95% confidence interval -2.94 to 7.37, p = 0.4). Two other RCTs also showed mixed effects of maca on several semen quality parameters in healthy men. Conclusion: The evidence from the included studies suggests unclear effects of maca on semen quality parameters in both men experiencing infertility and healthy men. However, the total number of RCTs and the total sample size were too small to draw firm conclusions.

Comparison of antimicrobial resistances and clinical features in community-onset Escherichia coli and Klebsiella pneumoniae bacteremia.

BACKGROUND/AIMS: The aim of this study was to compare antimicrobial resistance, clinical features, and outcomes of community-onset Escherichia coli (COEC) and Klebsiella pneumoniae (COKP) bacteremia. METHODS: The medical records of patients diagnosed with E. coli or K. pneumoniae bacteremia in the emergency department of a 750-bed secondary care hospital in Daegu, Korea from January 2010 to December 2016 were retrospectively reviewed. RESULTS: A total of 866 patients with COEC bacteremia and 299 with COKP bacteremia were enrolled. COEC bacteremia, compared to COKP bacteremia, had higher rates of 3rd generation cephalosporin (3GC) (18.8% vs. 8.4%, p < 0.001) and f luoroquinolone (FQ) (30.4% vs. 8.0%, p < 0.001) resistance. The patients with COKP bacteremia had higher Charlson comorbidity indices (CCI) (1.8 ± 2.0 vs. 1.5 ± 1.8, p = 0.035), Pittsburgh bacteremia scores (PBS) (2.0 ± 2.6 vs. 1.3 ± 1.8, p < 0.001), and 30-day mortality (14.44% vs. 8.8%, p = 0.008) than the patients with COEC bacteremia. Age younger than 70 years, male sex, polymicrobial infections, pneumonia, intra-abdominal infection, PBS ≥ 2, and Foley catheter insertion were independent predictive factors for COKP bacteremia compared to COEC bacteremia in the multivariate analysis. CCI, PBS, and intensive care unit admission were independent risk factors for 30-day mortality in the multivariate analysis. CONCLUSION: 3GCs and FQs are still useful for the empirical treatment of patients with probable COKP bacteremia. The patients with COKP bacteremia had worse outcomes because of its greater severity and more frequent underlying comorbidities.

Results of a phase III, 8-week, multicenter, prospective, randomized, double-blind, parallel-group clinical trial to assess the effects of amlodipine camsylate versus amlodipine besylate in Korean adults with mild to moderate hypertension.

BACKGROUND: Amlodipine besylate has been used in Korea for the treatment of hypertension for >17 years, with well-established efficacy and tolerability. Amlodipine camsylate is a newer formulation developed for generic use. It has been assessed in terms of physical stability and pharmacokinetic and pharmacodynamic properties and been found to be effective in lowering blood pressure in preclinical and Phase I and II trials. However, to date, no studies have compared the clinical effectiveness of amlodipine camsylate and amlodipine besylate in treating hypertension. OBJECTIVE: This study was designed to determine the effectiveness and tolerability of amlodipine camsylate compared with amlodipine besylate in Korean patients with mild to moderate hypertension. METHODS: This Phase III, 8-week, prospective, randomized, double-blind, parallel-group study was conducted in 13 cardiology centers across the Republic of Korea. Male and female Korean patients aged 18 to 75 years having uncomplicated, mild to moderate, essential hypertension (sitting diastolic blood pressure [SiDBP] 90-<110 mm Hg) and receiving no antihypertensives in the 2 weeks before randomization were eligible. Patients were randomly assigned to receive oral treatment with amlodipine camsylate or amlodipine besylate. For the first 4 weeks, patients received amlodipine 5 mg QD (morning). After 4 weeks, if either blood pressure was > or =140/ > or =90 mm Hg or SiDBP had not decreased by > or =10 mm Hg from baseline, the dose of amlodipine was increased to 10 mg QD for 4 weeks. Trough blood pressure and heart rate were measured in duplicate with the patient in the sitting position at each clinic visit (baseline [week 0] and weeks 4 and 8 of treatment); mean values were calculated and recorded. At weeks 4 and 8, tolerability was assessed using history taking and laboratory analysis, and compliance was assessed using pill counts. The primary end point was change from baseline in SiDBP at week 8. Secondary end points were change from baseline in sitting systolic blood pressure (SiSBP) at week 8 in the total population and in the subgroup of patients who had previously received antihypertensive treatment versus those who had not. RESULTS: A total of 189 patients were enrolled (mean age, 53 years; 105 women, 84 men; mean body weight, 65.8 kg). One patient in the amlodipine camsylate group dropped out of the study at week 0 of treatment (this patient did not use any study medication) and was excluded from the modified intent-to-treat (ITT) analysis. Thus, 188 patients were treated and included in the ITT analysis (94 patients per treatment group; ITT analysis); 161 patients were included in the perprotocol (PP) analysis (n = 80 for amlodipine camsylate, n = 81 for amlodipine besylate) (14 patients in the amlodipine camsylate group and 13 patients in the amlodipine besylate group were excluded from the PP analysis due to consistent withdrawal or protocol violation). Mean (SD) SiSBP and SiDBP were significantly decreased from baseline in both groups (amlodipine camsylate, from 146.7 [12.3]/96.6 [5.4] to 127.9 [14.8]/83.4 [7.7] mm Hg [both, P < 0.001]; amlodipine besylate, from 146.8 [12.8]/96.7 [5.1] to 128.0 [10.1]/83.8 [7.5] mm Hg [both, P < 0.001]). The differences in SiSBP/SiDBP between the 2 groups at week 8 were not significant. The SiDBP response rates in the subgroups that had and had not been previously treated with antihypertensives were statistically similar (56/69 [81.2%] and 83/92 [90.2%], respectively). The prevalences of clinical adverse events (AEs) were not significantly different between the 2 treatment groups (amlodipine camsylate, 27.3 %; amlodipine besylate, 28.7%). The most common AEs were dizziness and dyspnea (both in 3/94 [3.2%] and 1/94 [1.1%] patients who received amlodipine camsylate and amlodipine besylate, respectively). CONCLUSION: The effectiveness and tolerability of amlodipine camsylate were not significantly different from those of amlodipine besylate in these Korean adults with mild to moderate hypertension.