Field study of the indoor environments for preventing the spread of the SARS-CoV-2 in Seoul.

Despite the prolonged global spread of COVID-19, few studies have investigated the environmental influence on the spread of SARS-CoV-2 RNA with a metropolitan scale, particularly the detection of SARS-CoV-2 after disinfection at multi-use facilities. Between February 2020 and January 2021, 1,769 indoor air samples and object surfaces were tested at 231 multi-use facilities where confirmed cases were known to have occurred in Seoul, to determine whether SARS-CoV-2 RNA could be detected even after disinfection. Samples were collected by air scanner and swab pipette and detected by real-time RT-PCR. As a result, 10 (0.56%) positive samples were detected despite disinfection. The common environmental features of all 10 were surfaces that contained moisture and windowless buildings. With the aim of preventing the spread of COVID-19, from January to February 2021, we next conducted 643 preemptive tests before the outbreak of infections at 22 multi-use facilities where cluster infections were frequent. From these preemptive inspections, we obtained five (0.78%) positive results from two facilities, which enabled us to disinfect the buildings and give all the users a COVID-19 test. Based on the study purpose of finding and investigating cases of positive detection even after disinfection in the field through long-term environmental detection in a large city, our preemptive investigation results helped to prevent the spread of infectious diseases by confirming the potential existence of an asymptomatic patient.

Impacts of typhoon and heavy rain disasters on mortality and infectious diarrhea hospitalization in South Korea.

Several studies for health impacts of natural disasters have not been comprehensive with respect to disaster type and areas, nor quantitative. The aim of our study is to quantitatively examine the associations between disasters and human health in South Korea. This study considered "special disasters" that occurred from 2003 to 2009 in seven metropolitan cities and nine provinces in South Korea. First, we completed health impact counts in both disaster periods and reference periods. We then calculated the rate ratios between health impact counts in these two periods. Mortality is estimated to be higher in the case of typhoons, whereas morbidity is estimated to be higher in heavy rain disasters. The difference in health impacts of typhoons and heavy rain may be explained by the difference in meteorological exposure patterns. Consequentially, we suggest the development of properly adaptive plans against the influence of future natural disasters on human health.

Analyzing the Effect of Social Distancing Policies on Traffic at Sinchon Station, South Korea, during the COVID-19 Pandemic in 2020 and 2021.

The COVID-19 pandemic is recognized as one of the most serious global health problems, and many countries implemented lockdown measures to mitigate the effects of the crisis caused by this respiratory infectious disease. In this study, we investigated the relationship between social distancing policies and changes in traffic volume in Sinchon Station, South Korea. We used an official COVID-19 report provided by the Korea Disease Control and Prevention Agency (KCDA) and Seoul Metropolitan Government (SMG) to review social distancing policies, and the changes in traffic patterns before and during the COVID-19 pandemic between January 2020 and November 2021 were analyzed. Our study reveals that the changes in the overall traffic patterns from acceleration phases to deceleration phases of COVID-19 were related to the alert levels of social distancing policies implemented to tackle the situation resulting from the COVID-19 pandemic. Herein, we found that a significant decline in traffic volume took place from August to September 2020 (13.5−19.7%, weekday; 19.4−31.7%, weekend), from December 2020 to January 2021 (20.0%−26.6%, weekday; 26.8−34.0%, weekend), and from July to September 2021 (3.2−13.1%, weekday; 38.3−44.7%, weekend) when compared to the corresponding periods in 2019 (paired t-test; p < 0.001). The results of this study provide strong support for the effectiveness of Seoul's preemptive measures, namely, the central government's intensive social distancing campaign, in managing and reducing the impact of the pandemic situation based on the precise analysis of 10 types of facilities.

Brain lipidomics: From functional landscape to clinical significance.

Lipids are crucial components of cellular function owing to their role in membrane formation, intercellular signaling, energy storage, and homeostasis maintenance. In the brain, lipid dysregulations have been associated with the etiology and progression of neurodegeneration and other neurological pathologies. Hence, brain lipids are emerging as important potential targets for the early diagnosis and prognosis of neurological diseases. This review aims to highlight the significance and usefulness of lipidomics in diagnosing and treating brain diseases. We explored lipid alterations associated with brain diseases, paying attention to organ-specific characteristics and the functions of brain lipids. As the recent advances in brain lipidomics would have been impossible without advances in analytical techniques, we provide up-to-date information on mass spectrometric approaches and integrative analysis with other omic approaches. Last, we present the potential applications of lipidomics combined with artificial intelligence techniques and interdisciplinary collaborative research for treating brain diseases with clinical heterogeneities.

Reduction in urban atmospheric CO2 enhancement in Seoul, South Korea, resulting from social distancing policies during the COVID-19 pandemic.

With the spread of the COVID-19 virus globally, cities worldwide have implemented unprecedented social distancing policies to mitigate infection rates. Many studies have demonstrated that improved air quality and reduced carbon emissions have resulted from the COVID-19 pandemic. Yet, questions remain regarding changes in atmospheric CO2 concentrations because of the complex cycles involving the interaction of CO2 with the natural environment. In this study, we compared the changes in urban CO2 enhancement (△CO2) reflecting the contribution of local CO2 emissions to the atmospheric CO2 in urban areas, according to the intensity of social distancing policies implemented during the COVID-19 pandemic in Seoul, South Korea. We used data from three CO2 ground observation sites in the central area of Seoul and outside the urban area of Seoul. By comparing the urban CO2 concentration in Seoul with that of the background area using two different methods, considering both vertical and horizontal differences in CO2 concentration, we quantified the △CO2 of the pre-COVID-19 period and two COVID-19 periods, during which intensive social distancing policies with different intensities were implemented (Level 1, Level 2.5). During the pre-COVID-19 period, the average △CO2 calculated using the two methods was 24.82 ppm, and it decreased significantly to 16.42 and 14.36 ppm during the Level 1 and Level 2.5 periods, respectively. In addition, the urban contribution of Seoul to atmospheric CO2 concentration decreased from 5.27% during the pre-COVID-19 period to 3.54% and 3.19% during the Level 1 and Level 2.5 periods, respectively. The results indicate that the social distancing policies implemented in Seoul resulted in reduced local CO2 emissions, leading to a reduction in atmospheric CO2 concentration. Interestingly, it also shows that the extent of atmospheric CO2 concentration reduction can be greatly affected by the intensity of policies. Our study suggests that changes in human activity could reduce the urban direct contribution to the background CO2 concentration helping to further mitigate climate change.

An improved extraction method for acrylamide determination in fruit and vegetable chips through enzyme addition.

An enzyme-addition method to pretreat fried fruit and vegetable chips for acrylamide analysis is reported, followed by determination of the acrylamide contents in 36 marketed fruit and vegetable chip products using LC-MS/MS. To improve the extraction process, the FDA method was modified. Specifically, digestive enzymes were added, overcoming the clogging of filters (or SPE cartridges) after extraction of vegetable chips using water. Diastase was added to extract high-starch products, including potato chips. Recoveries of 90.3-105.5% acrylamide were obtained at the spiking levels of 25-500 µg/kg. LOD and LOQ were similar between the method with (4.5 and 13.7 µg/kg) and without diastase addition (4.4 and 13.2 µg/kg). Okra chip with high mucin content was extracted after adding pepsin. This method provided a recovery of 99.8-102.2%, LOD of 6.0 µg/kg, and LOQ of 18.1 µg/kg. Both methods could be used for analyzing acrylamide, with critical method parameters satisfying European Union regulations.

Atmospheric pressure-thermal desorption (AP-TD)/electrospray ionization-mass spectrometry for the rapid analysis of Bacillus spores.

A technique is described where an atmospheric pressure-thermal desorption (AP-TD) device and electrospray ionization (ESI)-mass spectrometry (MS) are coupled and used for the rapid analysis of Bacillus subtilis spores in complex matrices. The resulting AP-TD/ESI-MS technique combines the generation of volatile compounds and/or pyrolysis products with soft-ionization MS detection. In the AP-TD/ESI-MS approach, an electrospray solvent plume was used as the ionization vehicle of thermally desorbed neutrals at atmospheric pressure prior to mass spectrometric analysis using a quadrupole ion trap mass spectrometer. The approach is quantitative with the volatile standard dimethyl methylphosphonate (DMMP) and with the use of an internal standard (diethyl methylphosphonate, DEMP). A linear response was obtained as tested in the 1-50 ppm range (R(2) = 0.991) with a standard error of the estimate of 0.193 (0.9% RSD, n = 5). Bacterial spores were detected by performing pyrolysis in situ methylation with the reagent tetramethylammonium hydroxide (TMAH) for the detection of the bacterial spore biomarker dipicolinic acid (DPA) as the dimethylated derivative (2Me-DPA). This approach allowed spore detection even in the presence of growth media in crude lyophilized samples. Repetitive analyses could be performed with a duty cycle of less than 5 min total analysis time (including sample loading, heating and data acquisition). This strategy proved successful over other direct ambient MS approaches like DESI-MS and AP-TD/ESI-MS without the in situ derivatization step to detect the dipicolinic acid biomarker from spores. A detection limit for the dimethylated DPA biomarker was estimated at 1 ppm (equivalent to 0.01 mug of DPA deposited in the thermal desorption tube), which corresponded to a calculated detection limit of 10(5) spores deposited or 0.1% by weight spore composition in solid samples (assuming a 1 mg sample size). The AP-TD/ESI source used in conjunction with the in situ methylation step allowed the differentiation of bacterial spores from other 'suspicious white powders' using a single stage for mass analysis and with minimum sample preparation, making this approach suitable for simple field-portable MS instrumentation and pattern recognition data analysis.

Interrelationship of Pyrogenic Polycyclic Aromatic Hydrocarbon (PAH) Contamination in Different Environmental Media.

Interrelationships between pyrogenic polycyclic aromatic hydrocarbons (PAHs) were assessed in air, soil, water, sediment, and tree leaves by using multi-media monitoring data. Concurrent concentration measurements were taken bimonthly for a year for the multi-media at urban and suburban sites. PAH level correlations between air and other media were observed at the urban site but were less clear at the suburban site. Considering a closer PAHs distribution/fate characteristics to soil than suspended solids, contamination in sediment seemed to be governed primarily by that in soil. The partitioning of PAHs in waters could be better accounted for by sorption onto black carbon and dissolved organic carbon.

Desorption electrospray ionization mass spectrometry of intact bacteria.

Desorption electrospray ionization (DESI) mass spectrometry (MS) was used to differentiate seven bacteria species on the basis of their measured DESI-mass spectral profile. Both gram-positive and gram-negative bacteria were tested and included Escherichia coli, Staphyloccocus aureus, Enterococcus sp., Bordetella bronchiseptica, Bacillus thuringiensis, Bacillus subtilis and Salmonella typhimurium. Distinct DESI-mass spectra, in the mass range of 50-500 u, were obtained from whole bacteria in either positive or negative ion modes in less than 2 mins analysis time. Positive ion DESI-mass spectral fingerprints were compared using principal components analysis (PCA) to investigate reproducibility for the intraday and the day-to-day measurements and the method selectivity to differentiate the bacteria studied. Detailed study of variances in the assay revealed that a large contribution to the DESI-mass spectral fingerprint variation was the growth media preparation procedure. Specifically, experiments conducted with the growth media prepared using the same batch yielded highly reproducible DESI-mass spectra, both in intraday and in day-to-day analyses (i.e. one batch of growth media used over a 3-day period versus a new batch every day over the same 3-day period). Conclusions are drawn from our findings in terms of strategies for rapid biodetection with DESI-MS.

On-Probe Pyrolysis Desorption Electrospray Ionization (DESI) Mass Spectrometry for the Analysis of Non-Volatile Pyrolysis Products.

An on-probe pyrolyzer has been constructed and interfaced with Desorption Electrospray Ionization (DESI) Mass Spectrometry (MS) for the rapid analysis of non-volatile pyrolysis products. The detection and analysis of non-volatile pyrolysis products of peptides, proteins and the synthetic polymer poly(ethylene glycol) are demonstrated with this instrument. The on-probe pyrolyzer can be operated off-line or on-line with the DESI source and was interfaced with a tandem MS (MS/MS) instrument, which allowed for structure characterization of the non-volatile pyrolytic products. Advantages of this system are its simplicity and speed of analysis since the pyrolysis is performed in situ on the DESI source probe and hence, it avoids extraction steps and/or the use of matrices (e.g., as in MALDI-MS analyses).

Partial two-dimensional gel electrophoresis (2-DE) maps of Streptococcus iniae ATCC29178 and Lactococcus garvieae KG9408.

To examine the proteomes of 2 important causative agents of fish streptococcosis, Streptococcus iniae ATCC29178 and Lactococcus garvieae KG9408, we used 2-dimensional gel electrophoresis (2-DE) followed by mass spectrometry to generate 2-DE maps of these type strains. Silver-stained 2-DE gels of S. iniae ATCC29178 and L. garvieae KG9408 revealed approximately 320 and 300 spots, respectively, and immobilized pH gradient strips (13 cm, pH 4 to 7) revealed that the majority of the detected spots were concentrated in the pH range of 4.5 to 5.5. The spots were randomly selected from the 2-DE profiles and identified by peptide mass fingerprinting using matrix-assisted laser desorption/ionization time of flight mass spectrometry. The majority of the identified proteins were functionally related to energy and carbohydrate metabolism (e.g. enolase ATPase, glyceraldehyde-3-phosphate dehydrogenase) or translation and translocation (e.g. elongation factor G, elongation factor Tu, DNA-directed RNA polymerase alpha chain). These data, along with our partial 2-DE maps of S. iniae ATCC29178 and L. garvieae KG9408, may help suggest antigenic proteins for the development of effective diagnostic tools and vaccines against S. iniae and L. garvieae.

Production of monoclonal antibodies against serum immunoglobulins of black rockfish (Sebastes schlegeli Higendorf).

The present study was undertaken to produce monoclonal antibodies (MAbs) against immunoglobulin (Ig) purified from black rockfish (Sebastes schlegeli Higendorf) serum using protein A, mannan binding protein, and goat IgG affinity columns. These three different ligands were found to possess high affinity for black rockfish serum Ig. All of the Igs purified eluted at only 0.46 M NaCl concentration in anion exchange column chromatography and consisted of two bands at 70 kDa and 25 kDa in SDS-PAGE; they also had similar antigenicity for MAbs to Ig heavy chain in immunoblot assays. Therefore, black rockfish Ig is believed to exist as a single isotype within serum. The MAbs produced against Ig heavy chain reacted specifically with spots distributed over the pI range from 4.8 to 5.6 with a molecular weight of 70 kDa on two dimensional gel electrophoresis immunoblot profiles.

Physiological function of insoluble dietary fiber prepared from exploded oak wood (Quercus mongolica).

This study investigated the production of insoluble dietary fiber using exploded and chemically treated oak wood (Quercus mongolica) and the physiological functions of prepared insoluble dietary fiber in laboratory animals. To produce high quality insoluble dietary fiber, the steam explosion treatment was performed at 25 kgf/cm2 pressure for 6 minutes. In the chemical analysis of insoluble dietary fiber, exploded oak wood was pretreated by 1% sodium hydroxide solution. The insoluble dietary fiber contained 7.6% residual lignin and 61.7% of alpha-cellulose. In order to compare the physiological functions of prepared insoluble dietary fiber with those of commercial insoluble dietary fiber, Sprague-Dawley male rats weighing 100 +/- 10 g were randomly assigned to one normal diet and five high cholesterol diets, containing 1% cholesterol. The high cholesterol diet groups were classified as the fiber-free diet (FF group), 5% commercial alpha-cellulose diet group (5C group), 10% commercial alpha-cellulose group (10C group), 5% insoluble dietary fiber group (5M group) and 10% insoluble dietary fiber group (10M group). Food intake, weight gain and food efficiency ratio in high cholesterol groups were significantly higher than those of the normal group, but there were no significant differences among the high cholesterol diet groups. In addition, there were no significant differences in the weights of liver, kidney and small intestine in insoluble dietary fiber-supplemented groups. Cecum weights in all insoluble dietary fiber groups were significantly higher than those of the FF group. There were no significant differences in the activities of the glutamic pyruvic transaminase (GPT) and glutamic oxaloacetic transaminase (GOT) among the insoluble dietary fiber-supplemented groups. In conclusion, the prepared insoluble dietary fiber and the commercially available insoluble fiber showed the same physiological effects. Moreover, the preparation method for the insoluble dietary fiber from the exploded oak wood was successful.

Application of proteomics for comparison of proteome of Neospora caninum and Toxoplasma gondii tachyzoites.

Protein profiles of two isolates of Neospora caninum (KBA-2 and JPA1) and Toxoplasma gondii RH strain were investigated by proteomic approach. Approximately, 78% of protein spots on two-dimensional gel electrophoresis (2-DE) profiles and 80% of antigen spots on 2-DE immunoblotting profiles were exhibited to share the same pI and M(r) between KBA-2 and JPA1 of N. caninum. On the other hand, a total of 30 antigen spots of T. gondii were recognized on 2-DE immunoblotting profile using rabbit antiserum against N. caninum KBA-2. A number of homologue proteins, such as heat shock protein 70, tubulin alpha- and beta-chain, putative protein disulfide isomerase, actin, enolase and 14-3-3 protein homologue are believed as the conserved proteins in both N. caninum and T. gondii. On the contrary, NcSUB1, NcGRA2 and NCDG1 (NcGRA7) might be the species-specific proteins for N. caninum tachyzoites. The present study showed that the high degree of similarity between N. caninum isolates (KBA-2 and JPA1), whereas large differences between N. caninum and T. gondii were noticed by proteome comparisons.

Comparison of proteome and antigenic proteome between two Neospora caninum isolates.

This study was conducted to explore the relationship between two isolates of Neospora caninum (N. caninum) (KBA-2 and VMDL-1) using proteomics. To achieve the goal, proteins of N. caninum tachyzoite lysates of KBA-2 and VMDL-1 were separated by two-dimensional gel electrophoresis (2-DE), stained with silver-nitrate and analyzed using matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS) to compare protein profiles. In addition, proteins separated by 2-DE were transferred to membranes, probed with bovine anti-N. caninum KBA-2 immunoglobulin G, and reactive proteins were visualized and compared between the two isolates. Most spots on 2-DE profiles and antigenic spots on 2-DE immunoblot profiles were located at similar locations in terms of isoelectric point and molecular weight. Proteins common to both isolates included the following: heat shock protein 70, subtilisin-like serine protease, nucleoside triphosphatase, heat shock protein 60, pyruvate kinase, tubulin alpha, tubulin beta, enolase, putative protein disulfide isomerase, actin, fructase-1,6-bisphosphatase, putative ribosomal protein S2, microneme protein Nc-P38, lactate dihydrogenase, fructose-1,6-bisphosphatase aldolase, serine threonine phosphatase 2C, 14-3-3 protein homologue, N. caninum dense granule-1 and NcGRA2. As a consequence, even though N. caninum KBA-2 and VMDL-1 isolates were isolated from geographically distinct locations there were significant homology in the proteome and antigenic proteome profiles. In addition, proteomic approach was verified as a useful tool for understanding of host immune response against different isolates of protozoa.

Exploration of immunoblot profiles of Neospora caninum probed with different bovine immunoglobulin classes.

The present study was attempted to compare the Neospora caninum (N. caninum) antigenic bands recognized by different bovine immunoglobulin classes. A total 10, 5, 2, and 6 antigenic bands were exhibited on immunoblot profiles against bovine IgM, IgE, IgA, and IgG, respectively. A 46 kDa band was probed as a common antigenic band except IgA; 69 kDa band was bovine IgM and IgE; 33, 37, 55, and 79 kDa bands were bovine IgM and IgG; 72 kDa band was found IgM and IgA profiles. Based on the analysis, it appeared that different immunoglobulin classes recognizing different antigenic molecules were cooperating to cope with neosporosis.

Utilization of health insurance data in an environmental epidemiology.

OBJECTIVES: In South Korea, health insurance data are used as material for the health insurance of national whole subject. In general, health insurance data could be useful for estimating prevalence or incidence rate that is representative of the actual value in a population. The purpose of this study was to apply the concept of episode of care (EoC) in the utilization of health insurance data in the field of environmental epidemiology and to propose an improved methodology through an uncertainty assessment of disease course and outcome. METHODS: In this study, we introduced the concept of EoC as a methodology to utilize health insurance data in the field of environmental epidemiology. The characterization analysis of the course and outcome of applying the EoC concept to health insurance data was performed through an uncertainty assessment. RESULTS: The EoC concept in this study was applied to heat stroke (International Classification of Disease, 10th revision, code T67). In the comparison of results between before and after applying the EoC concept, we observed a reduction in the deviation of daily claims after applying the EoC concept. After that, we categorized context, model, and input uncertainty and characterized these uncertainties in three dimensions by using uncertainty typology. CONCLUSIONS: This study is the first to show the process of constructing episode data for environmental epidemiological studies by using health insurance data. Our results will help in obtaining representative results for the processing of health insurance data in environmental epidemiological research. Furthermore, these results could be used in the processing of health insurance data in the future.

Reference map of soluble proteins from Salmonella enterica serovar Enteritidis by two-dimensional electrophoresis.

Protein identification by peptide mass fingerprinting using matrix-assisted laser desorption ionization time of fight (MALDI-TOF) mass spectrometry (MS) can analyze unambiguously identity of the spots from a 2-dimensional electrophoresis (2-DE) gel. This study developed a technique for 2-DE of Salmonella enterica serovar Enteritidis (S. enteritidis) by improving the dissolution conditions by 2-DE using a pH 4 - 7 immobilized pH gradient (IPG) strip. This report examines the protein components from the patterns of the S. enteritidis protein. The most abundant protein displayed a great number of clusters within the pH 4.5 - 7 range with a molecular mass ranging from 35-80 kDa. Some of these spots were identified as metabolic related enzymes. The protein fraction was also analyzed using an immobilized pH gradient strip. Different proteins were identified on the spot according to the elongation factors. In addition, this study showed that the 2-DE analysis of S. enteritidis provides useful information regarding the S. enteritidis proteome, and this approach might provide a strategy for identifying bacterial proteins using a proteome technology.

Two-dimensional gel electrophoresis and immunoblot analysis of Neospora caninum tachyzoites.

Identification of expressed protein profiles and antigenic determination are some of the most challenging aspects of proteomics. Two-dimensional gel electrophoresis (2-DE) combined with immunoblot analysis were employed to study the N. caninum proteome. Protein sample preparation was carried out by first conducting sonication, followed by adding lysis buffer containing 7M urea plus 2M thiourea to the purified tachyzoites in order to complete disruption. A total of 335 differentially expressed protein spots were detected using pH 4-7 IPG strip (7 cm) that were run in a 56 kVh isoelectric focusing (IEF) system. Of the spots analyzed, 64 were identified as antigenic spots on immunoblot profile. Major antigenic spots appeared at 65 kDa (pI 5.2-5.3), 51 kDa (pI 5.5), 38 kDa (pI 5.1), 33 kDa (pI 4.4), 29 kDa (pI 5.6) and 15.5 kDa (pI 5.0) were observed to be significantly distinct compared to the rest of the antigenic spots. The results indicate that combination of 2-DE and immunoblotting methods were thought as very useful tools in defining both proteins and antigens of N. caninum tachyzoites. Additionally, present 2-DE profiles may be valuable in further proteomic approaches and study of the pathogen.

Wavelength-Filter Based Spectral Calibrated Wave number - Linearization in 1.3 mm Spectral Domain Optical Coherence.

In this study, we demonstrate the enhanced spectral calibration method for 1.3 µm spectral-domain optical coherence tomography (SD-OCT). The calibration method using wavelength-filter simplifies the SD-OCT system, and also the axial resolution and the entire speed of the OCT system can be dramatically improved as well. An externally connected wavelength-filter is utilized to obtain the information of the wavenumber and the pixel position. During the calibration process the wavelength-filter is placed after a broadband source by connecting through an optical circulator. The filtered spectrum with a narrow line width of 0.5 nm is detected by using a line-scan camera. The method does not require a filter or a software recalibration algorithm for imaging as it simply resamples the OCT signal from the detector array without employing rescaling or interpolation methods. One of the main drawbacks of SD-OCT is the broadened point spread functions (PSFs) with increasing imaging depth can be compensated by increasing the wavenumber-linearization order. The sensitivity of our system was measured at 99.8 dB at an imaging depth of 2.1 mm compared with the uncompensated case.