Numerical Implementation of Representative Mobile Phone Models for Epidemiological Studies

This paper describes an implementation method and the results of numerical mobile phone models representing real phone models that have been released on the Korean market since 2002. The aim is to estimate the electromagnetic absorption in the human brain for casecontrol studies to investigate health risks related to mobile phone use. Specific absorption rate (SAR) compliance test reports about commercial phone models were collected and classified in terms of elements such as the external body shape, the antenna, and the frequency band. The design criteria of a numerical phone model representing each type of phone group are as follows. The outer dimensions of the phone body are equal to the average dimensions of all commercial models with the same shape. The distance and direction of the maximum SAR from the earpiece and the area above –3 dB of the maximum SAR are fitted to achieve the average obtained by measuring the SAR distributions of the corresponding commercial models in a flat phantom. Spatial peak 1-g SAR values in the cheek and tilt positions against the specific anthropomorphic mannequin phantom agree with average data on all of the same type of commercial models. Second criterion was applied to only a few types of models because not many commercial models were available. The results show that, with the exception of one model, the implemented numerical phone models meet criteria within 30%

Increase of Ceftazidime- and Fluoroquinolone-Resistant Klebsiella pneumoniae and Imipenem-Resistant Acinetobacter spp. in Korea: Analysis of KONSAR Study Data from 2005 and 2007

PURPOSE: Antimicrobial resistance monitoring could be a useful source of information for treating and controlling nosocomial infections. We analyzed antimicrobial resistance data generated by Korean Hospitals and by a commercial laboratory in 2005 and 2007. MATERIALS AND METHODS: Susceptibility data for 2005 and 2007 were collected from 37 and 41 hospitals, respectively, and from one commercial laboratory. Intermediate susceptibility was not included in the calculation of resistance rates. RESULTS: Methicillin-resistant Staphylococcus aureus (MRSA) (64%), third-generation cephalosporin-resistant Klebsiella pneumoniae (29%), fluoroquinolone-resistant Escherichia coli (27%), Pseudomonas aeruginosa (33%), and Acinetobacter spp. (48%), and amikacin-resistant P. aeruginosa (19%) and Acinetobacter spp. (37%) were prevalent in hospitals in 2007. A gradual increase of vancomycin-resistant Enterococcus faecium and imipenem-resistant Acinetobacter spp. was observed. Higher incidences of thirdgeneration cephalosporin-resistant E. coli and K. pneumoniae and imipenemresistant P. aeruginosa were found in the commercial laboratory than in the hospitals. CONCLUSION: Methicillin-resistant S. aureus, third-generation cephalosporin- resistant K. pneumoniae, and fluoroquinolone-resistant E. coli, P. aeruginosa and Acinetobacter spp. remain prevalent in Korea, while the incidence of vancomycin-resistant E. faecium and imipenem-resistant Acinetobacter spp. has increased gradually. The higher prevalences of third-generation cephalosporinresistant E. coli and K. pneumoniae, and imipenem-resistant P. aeruginosa in the commercial laboratory are a new concern.ope

Development of a Numerical Tablet Model in WLAN Band for SAR Study

This research proposes a numerical model for a tablet in the wireless local area network band for specific absorption rate (SAR) study. The design criteria, such as the tablet size, operating frequencies, antenna position, and target 1-g peak spatial-average SAR (psSAR) values in the flat phantom, are determined based on the SAR test reports of tablets distributed in South Korea from 2013 to 2017. An internal antenna is designed in a tablet platform to operate in dual bands of 2,450 MHz and 5,500 MHz. The numerical results illustrate that the 1-g psSAR values of the proposed numerical tablet model are within ±10% of the target values. Moreover, the return loss of the designed tablet model is larger than 10 dB, regardless of flat phantom, while its radiation efficiency is higher than 90% in free space

Validation and proposal for cut-off values of an abbreviated version of the Alcohol Use Disorder Identification Test using the Korean National Health and Nutrition Examination Survey

Objective Several abbreviated versions of the Alcohol Use Disorder Identification Test (AUDIT) have been developed and are widely used in clinical settings. In this study, we provide evidence supporting the use of abbreviated versions of AUDIT by comparing the utility of various abbreviated versions and determining cut-off values for the population of South Korea. Methods Data were obtained from the 4th to 6th Korean National Health and Nutrition Examination Surveys. After calculating the whole AUDIT score, we applied the cut-off value of at-risk drinking proposed by the World Health Organization and divided the study sample into normal and at-risk drinking groups. Receiver operating characteristic curves were drawn for AUDIT-3rd question (Q3) alone, AUDIT-quantity and frequency (QF), AUDIT-consumption (C), AUDIT-4, and AUDIT-primary clinic (PC), and optimal cut-off values were obtained for each group. Results A total of 46,450 subjects were analyzed. The at-risk drinking group comprised 29.2% of all subjects. The area under receiver operating characteristic curve (AUROC) of the abbreviated versions of AUDIT increased from 0.954 to 0.991 as the number of questions increased from one to four. The differences in AUROC between the abbreviated versions of AUDIT were statistically significant. The most appropriate cut-off values for AUDIT-Q3 alone, AUDIT-QF, AUDIT-C, AUDIT-4, and AUDIT-PC for adults over age 19 were 2, 4, 5, 6, and 4 points, respectively. Conclusion As the number of items analyzed increased from one to four items, the AUROC increased to a statistically significant level. Cut-off values for abbreviated versions of AUDIT are similar in South Korea to other countries

Cellular and Tissue Selectivity of AAV Serotypes for Gene Delivery to Chondrocytes and Cartilage

Background: Despite several studies on the effect of adeno-associated virus (AAV)-based therapeutics on osteoarthritis (OA), information on the transduction efficiency and applicable profiles of different AAV serotypes to chondrocytes in hard cartilage tissue is still limited. Moreover, the recent discovery of additional AAV serotypes makes it necessary to screen for more suitable AAV serotypes for specific tissues. Here, we compared the transduction efficiencies of 14 conventional AAV serotypes in human chondrocytes, mouse OA models, and human cartilage explants obtained from OA patients. Methods: To compare the transduction efficiency of individual AAV serotypes, green fluorescent protein (GFP) expression was detected by fluorescence microscopy or western blotting. Likewise, to compare the transduction efficiencies of individual AAV serotypes in cartilage tissues, GFP expression was determined using fluorescence microscopy or immunohistochemistry, and GFP-positive cells were counted. Results: Only AAV2, 5, 6, and 6.2 exhibited substantial transduction efficiencies in both normal and OA chondrocytes. All AAV serotypes except AAV6 and rh43 could effectively transduce human bone marrow mesenchymal stem cells. In human and mouse OA cartilage tissues, AAV2, AAV5, AAV6.2, AAV8, and AAV rh39 showed excellent tissue specificity based on transduction efficiency. These results indicate the differences in transduction efficiencies of AAV serotypes between cellular and tissue models. Conclusions: Our findings indicate that AAV2 and AAV6.2 may be the best choices for AAV-mediated gene delivery into intra-articular cartilage tissue. These AAV vectors hold the potential to be of use in clinical applications to prevent OA progression if appropriate therapeutic genes are inserted into the vector

The serum level of 25-hydroxyvitamin D for maximal suppression of parathyroid hormone in children: the relationship between 25-hydroxyvitamin D and parathyroid hormone

PurposeSerum level of 25-hydroxyvitamin D (25-OHD) is considered as the most appropriate marker of vitamin D status. However, only a few studies have investigated the relationship between 25-OHD and parathyroid hormone (PTH) in children. To this end, this study was aimed at evaluating the lowest 25-OHD level that suppresses the production of parathyroid hormone in children.MethodsA retrospective record review was performed for children aged 0.2 to 18 years (n=193; 106 boys and 87 girls) who underwent simultaneous measurements of serum 25-OHD and PTH levels between January 2010 and June 2014.ResultsThe inflection point of serum 25-OHD level for maximal suppression of PTH was at 18.0 ng/mL (95% confidence interval, 14.3–21.7 ng/mL). The median PTH level of the children with 25-OHD levels of <18.0 ng/mL was higher than that of children with 25-OHD levels ≥ 18.0 ng/mL (P<0.0001). The median calcium level of children with 25-OHD levels<18.0 ng/mL was lower than that of children with 25-OHD levels≥18.0 ng/mL (P=0.0001). The frequency of hyperparathyroidism was higher in the children with 25-OHD levels<18.0 ng/mL than in the children with 25-OHD levels≥18.0 ng/mL (P<0.0001). Hypocalcemia was more prevalent in the children with 25-OHD levels<18.0 ng/mL than in the children with 25-OHD levels≥18.0 ng/mL (P<0.0001).ConclusionThese data suggest that a vitamin D level of 18.0 ng/mL could be the criterion for 25-OHD deficiency in children at the inflection point of the maximal suppression of PTH

Multiple assessment methods of prenatal exposure to radio frequency radiation from telecommunication in the Mothers and Children’s Environmental Health (MOCEH) study

Objectives: To evaluate prenatal exposure to radiofrequency radiation (RFR) from telecommunication using a mobile phone questionnaire, operator data logs of mobile phone use and a personal exposure meter (PEM). Material and Methods: The study included 1228 mother–infants pairs from the Mothers and Children’s Environmental Health (MOCEH) study – a multicenter prospective cohort study ongoing since 2006, in which participants were enrolled at ≤ 20 weeks of pregnancy, with a follow-up of a child birth and growth to assess the association between prenatal environmental exposure and children’s health. The questionnaire included the average calling frequency per day and the average calling time per day. An EME Spy 100 PEM was used to measure RFR among 269 pregnant women from November 2007 to August 2010. The operators’ log data were obtained from 21 participants. The Spearman’s correlation test was performed to evaluate correlation coefficient and 95% confidence intervals between the mobile phone use information from the questionnaire, operators’ log data, and data recorded by the PEM. Results: The operators’ log data and information from the self-reported questionnaire showed significantly high correlations in the average calling frequency per day (ρ = 0.6, p = 0.004) and average calling time per day (ρ = 0.5, p = 0.02). The correlation between information on the mobile phone use in the self-reported questionnaire and exposure index recorded by the PEM was poor. But correlation between the information of the operators’ log data and exposure index for transmission of mobile communication was significantly high: correlation coefficient (p-value) was 0.44 (0.07) for calling frequency per day, and it was 0.49 (0.04) for calling time per day. Conclusions: The questionnaire information on the mobile phone use showed moderate to high quality. Using multiple methods for exposure assessment might be better than using only one method. Int J Occup Med Environ Health 2016;29(6):959–97

Nidogen Plays a Role in the Regenerative Axon Growth of Adult Sensory Neurons Through Schwann Cells

We previously reported that nidogen is an extracellular matrix protein regulating Schwann cell proliferation and migration. Since Schwann cells play a critical role in peripheral nerve regeneration, nidogen may play a role in it via regulation of Schwann cells. Here, we demonstrate direct evidence that nidogen induces elongation of regenerative axon growth of adult sensory neurons, and that the effect is Schwann cell dependent. Continuous infusion of recombinant ectodomain of tumor endothelial marker 7, which specifically blocks nidogen function in Schwann cells, suppressed regenerative neurite growth in a sciatic nerve axotomy model. Taken together, it is likely that nidogen is required for proper regeneration of peripheral nerves after injury

A low risk of nosocomial transmission of subclinical tuberculosis to neonates in a postpartum care center under COVID-19 control measures

We report the results of investigating and managing a tuberculosis (TB) exposure in a postpartum care center. Among the contacts exposed to a nursing assistant with subclinical TB, 5 of 44 neonates (11.4%) had positive tuberculin skin tests (TSTs) at 3 months of age, and all the TST-positive neonates received the Bacille Calmette-Guérin vaccination. Seven of 28 healthcare workers (25.0%) and 1 of 3 household contacts (33.3%) were positive in the initial or repeated interferon-gamma release assay. None of the contacts developed TB disease during the study period. Annual TB examinations of healthcare personnel at a postpartum care center under the Tuberculosis Prevention Act in South Korea enabled the early detection of subclinical TB, which reduced the risk of transmission to neonates under strict coronavirus disease 2019 prevention measures