Liquid chromatographic resolution of fendiline and its analogues on a chiral stationary phase based on (+)-(18-crown-6)-2,3,11,12-tetracarboxylic acid.

Fendiline, an effective anti-anginal drug for the treatment of coronary heart diseases, and its sixteen analogues were resolved on a CSP based on (+)-(18-crown-6)-2,3,11,12-tetracarboxylic acid. Fendiline was resolved quite well with the separation factor (α) of 1.25 and resolution (RS) of 1.55 when a mobile phase consisting of methanol-acetonitrile-trifluoroacetic acid-triethylamine at a ratio of 80/20/0.1/0.5 (v/v/v/v) was used. The comparison of the chromatographic behaviors for the resolution of fendiline and its analogues indicated that the 3,3-diphenylpropyl group bonded to the secondary amino group of fendiline is important in the chiral recognition and the difference in the steric bulkiness between the phenyl group and the methyl group at the chiral center of fendiline is also important in the chiral recognition.

Preparation of Non-Isocyanate Polyurethanes from Mixed Cyclic-Carbonated Compounds: Soybean Oil and CO2-Based Poly(ether carbonate).

This study presents the synthesis and characterization of non-isocyanate polyurethanes (NIPU) derived from the copolymerization of cyclic-carbonated soybean oil (CSBO) and cyclic carbonate (CC)-terminated poly(ether carbonate) (RCC). Using a double-metal cyanide catalyst, poly(ether carbonate) polyol was first synthesized through the copolymerization of carbon dioxide and propylene oxide. The terminal hydroxyl group was then subjected to a substitution reaction with a five-membered CC group using glycerol-1,2-carbonate and oxalyl chloride, yielding RCC. Attempts to prepare NIPU solely using RCC and diamine were unsuccessful, possibly due to the low CC functionality and the aminolysis of RCC's linear carbonate repeating units. However, when combined with CSBO, solid NIPUs were successfully obtained, exhibiting good thermal stability along with enhanced mechanical properties compared to conventional CSBO-based NIPU formulations. Overall, this study underscores the potential of leveraging renewable resources and carbon capture technologies to develop sustainable NIPUs with tailored properties, thereby expanding their range of applications.

Prognostic utility of paraspinal muscle index in elderly patients with community-acquired pneumonia.

OBJECTIVE: This study investigated the associations between paraspinal muscle measurements on chest computed tomography and clinical outcomes of elderly patients with community-acquired pneumonia (CAP). METHODS: This single-center, retrospective, observational study analyzed elderly patients (≥65 years) with CAP hospitalized through an emergency department between March 2020 and December 2022. We collected their baseline characteristics and laboratory data at the time of admission. The paraspinal muscle index and attenuation were calculated at the level of the 12th thoracic vertebra using chest computed tomography taken within 48 hours before or after admission. Univariable and multivariable logistic regression analyses were conducted to evaluate the association between paraspinal muscle measurements and 28-day mortality. Receiver operating characteristic (ROC) curve and area under the curve (AUC) analyses were used to evaluate the prognostic predictive power. RESULTS: Of the 338 enrolled patients, 60 (17.8%) died within 28 days after admission. A high paraspinal muscle index was associated with low 28-day mortality in elderly patients with CAP (adjusted odds ratio, 0.994; 95% confidence interval, 0.992-0.997). The area under the ROC curve for the muscle index was 0.75, which outperformed the pneumonia severity index and the CURB-65 (confusion, urea, respiratory rate, blood pressure, age ≥65 years) metric, both of which showed an AUC of 0.64 in predicting mortality. CONCLUSION: A high paraspinal muscle index was associated with low 28-day mortality in patients aged 65 years or older with CAP.

Preparation of Remote Plasma Atomic Layer-Deposited HfO2 Thin Films with High Charge Trapping Densities and Their Application in Nonvolatile Memory Devices.

Optimization of equipment structure and process conditions is essential to obtain thin films with the required properties, such as film thickness, trapped charge density, leakage current, and memory characteristics, that ensure reliability of the corresponding device. In this study, we fabricated metal-insulator-semiconductor (MIS) structure capacitors using HfO2 thin films separately deposited by remote plasma (RP) atomic layer deposition (ALD) and direct-plasma (DP) ALD and determined the optimal process temperature by measuring the leakage current and breakdown strength as functions of process temperature. Additionally, we analyzed the effects of the plasma application method on the charge trapping properties of HfO2 thin films and properties of the interface between Si and HfO2. Subsequently, we synthesized charge-trapping memory (CTM) devices utilizing the deposited thin films as charge-trapping layers (CTLs) and evaluated their memory properties. The results indicated excellent memory window characteristics of the RP-HfO2 MIS capacitors compared to those of the DP-HfO2 MIS capacitors. Moreover, the memory characteristics of the RP-HfO2 CTM devices were outstanding as compared to those of the DP-HfO2 CTM devices. In conclusion, the methodology proposed herein can be useful for future implementations of multiple levels of charge-storage nonvolatile memories or synaptic devices that require many states.

COVID-19 Vaccine Perception in South Korea: Web Crawling Approach.

BACKGROUND: The US Centers for Disease Control and Prevention and the World Health Organization emphasized vaccination against COVID-19 because physical distancing proved inadequate to mitigate death, illness, and massive economic loss. OBJECTIVE: This study aimed to investigate Korean citizens' perceptions of vaccines by examining their views on COVID-19 vaccines, their positive and negative perceptions of each vaccine, and ways to enhance policies to increase vaccine acceptance. METHODS: This cross-sectional study analyzed posts on NAVER and Instagram to examine Korean citizens' perception of COVID-19 vaccines. The keywords searched were "vaccine," "AstraZeneca," and "Pfizer." In total 8100 posts in NAVER and 5291 posts in Instagram were sampled through web crawling. Morphology analysis was performed, overlapping or meaningless words were removed, sentiment analysis was implemented, and 3 public health professionals reviewed the results. RESULTS: The findings revealed a negative perception of COVID-19 vaccines; of the words crawled, the proportion of negative words for AstraZeneca was 71.0% (476/670) and for Pfizer was 56.3% (498/885). Among words crawled with "vaccine," "good" ranked first, with a frequency of 13.43% (312/2323). Meanwhile, "side effect" ranked highest, with a frequency of 29.2% (163/559) for "AstraZeneca," but 0.6% (4/673) for "Pfizer." With "vaccine," positive words were more frequently used, whereas with "AstraZeneca" and "Pfizer" negative words were prevalent. CONCLUSIONS: There is a negative perception of AstraZeneca and Pfizer vaccines in Korea, with 1 in 4 people refusing vaccination. To address this, accurate information needs to be shared about vaccines including AstraZeneca, and the experiences of those vaccinated. Furthermore, government communication about risk management is required to increase the AstraZeneca vaccination rate for herd immunity before the vaccine expires.

The relationship between trends in COVID-19 prevalence and traffic levels in South Korea.

OBJECTIVE: The World Health Organization (WHO) declared a COVID-19 pandemic on March 12, 2020. Several studies have indicated that densely populated urban environments and the heavy dependence on traffic could increase the potential spread of COVID-19. This study investigated the association between changes in traffic volume and the spread of COVID-19 in South Korea. METHODS: This study analyzed the daily national traffic and traffic trend for 3 months from January 1, 2020. Traffic data were measured using 6307 vehicle detection system (VDS). This study analyzed the difference in traffic levels between 2019 and 2020. Non-linear regression was performed to analyze the change in traffic trend in 2020. The relationship between traffic and confirmed COVID-19 cases was analyzed using single linear regression. RESULTS: The mean daily nationwide level of traffic for the first 3 months of 2020 was 143 655 563 vehicles, which was 9.7% lower than the same period in 2019 (159 044 566 vehicles). All regions showed a decreasing trend in traffic in February, which shifted to an increasing trend from March. In Incheon there was a positive, but insignificant, linear relationship between increasing numbers of newly confirmed cases and increasing traffic (ß = 43 146; p = 0.056). CONCLUSIONS: Numbers of newly confirmed COVID-19 patients have been decreasing since March, while the traffic has been increasing. The fact that traffic is increasing indicates greater contact between people, which in turn increases the risk of further COVID-19 spread. Therefore, the government will need to devise suitable policies, such as total social distancing.

Liver volume-based prediction model stratifies risks for hepatocellular carcinoma in chronic hepatitis B patients on surveillance.

BACKGROUND AND AIM: The aim of this study was to determine whether dynamic computed tomography (CT)-measured liver volume predicts the risk of hepatocellular carcinoma (HCC) when the CT scans do not reveal evidence of HCC in chronic hepatitis B (CHB) patients on surveillance. METHODS: This retrospective multicentre cohort study included 1,246 patients who received entecavir and regular HCC surveillance in three tertiary referral centres in South Korea. Liver volumes were measured on portal venous phase CT images. A nomogram was developed based on Cox independent predictors and externally validated. Time-dependent receiver operating characteristic (ROC) analysis was performed for comparison with previous prediction models. RESULTS: Patients who received dynamic CT studies during surveillance had significantly higher risk for HCC compared to patients without CT studies (hazard ratio [HR] = 3.1; p < 0.001). Expected/measured liver volume ratio was an independent predictor of HCC (HR = 4.2; p = 0.002) in addition to age, sex and cirrhosis. The nomogram based on the four predictors discriminated risks for HCC (HR = 4.1 and 6.0 in derivation and validation cohort, respectively, for volume score > 150; p < 0.001). Time-dependent ROC analysis confirmed better performance of the volume score compared to HCC prediction models with conventional predictors (integrated area under curve = 0.758 vs. 0.661-0.712; p < 0.05). CONCLUSIONS: CT-measured liver volume is an independent predictor of future HCC, and nomogram-based liver volume score may stratify the risks of HCC in CHB patients who showed negative CT findings for HCC during surveillance.

Impact of nucleos(t)ide analog treatment on the development of malignancy in patients with chronic hepatitis B.

We evaluated whether nucleos(t)ide analog (NA) influences the risk of non-hepatocellular carcinoma (non-HCC) malignancies in patients with chronic hepatitis B (CHB). A total of 9867 patients with CHB were followed up for ≥12 months for the occurrence of any type of malignancy between 1998 and 2013. Patients who received NA for ≥180 days were defined as the NA group. Propensity score matching produced the control (n = 2220) and NA groups (n = 2220) after adjustment for age, sex, and the presence of diabetes mellitus and liver cirrhosis. The National Health Insurance Service sample cohort dataset was used for external validation. Regarding non-HCC malignancies, only old age was an independent risk factor (>50 years; hazard ratio 3.17, 95% confidence interval 1.71-5.88, P < .001) in multivariate analysis. With regard to specific cancers such as thyroid, breast, lung, stomach, colorectal, pancreatobiliary, and hematologic malignancy, there was no difference of the incidence of each malignancy between the NA and control groups in both the hospital-based and external validation cohorts. NA treatment neither raises nor lowers the incidence of non-HCC malignancies in patients with CHB. Patients >50 years old are encouraged to undergo surveillance for malignancies similar to the general population.

A case of asymptomatic, localized, and idiopathic diffuse alveolar damage.

Diffuse alveolar damage (DAD) is a histological change in lung tissue, and is generally caused by an acute lung injury, which is characterized by bilateral and widespread damages. Localized DAD occurs very rarely. The causes for DAD are numerous, but the chief cause is acute interstitial pneumonia or acute exacerbation of idiopathic interstitial pneumonia, in cases of idiopathic manifestation. The 82-year-old patient, in this case study, showed a DAD lesion in only 1 lobe. The patient was otherwise healthy, with no previous symptoms of DAD. He was admitted to our medical center owing to localized infiltration, observed on his chest radiograph. Laboratory studies showed no signs of infections. DAD was confirmed by a surgical lung biopsy. The patient received corticosteroid treatment and had gradually improved. We report the case of a patient with localized, idiopathic DAD that cannot be classified as acute interstitial pneumonia or acute exacerbation of idiopathic interstitial pneumonia.