Chemical upcycling of PVC-containing plastic wastes by thermal degradation and catalysis in a chlorine-rich environment.

Chlorine (Cl)-containing chemicals, including hydrogen chloride, generated during thermal degradation of polyvinyl chloride (PVC) and corresponding mixture impede the chemical recycling of PVC-containing plastic wastes. While upgrading plastic-derived vapors, the presence of Cl-containing chemicals may deactivate the catalysts. Accordingly, herein, catalytic upgrading of pyrolysis vapor prepared from a mixture of PVC and polyolefins is performed using a fixed-bed reactor comprising zeolites. Among the H-forms of zeolites (namely, ZSM-5, Y, ß, and chabazite) used in this study, a higher yield of gas products composed of hydrocarbons with lower carbon numbers is obtained using H-ZSM-5, thus indicating further decomposition of the pyrolysis vapor to C1-C4 hydrocarbons on it. Although the formation of aromatic compounds is better on H-ZSM-5, product distributions can be adjusted by further modifying the acidic properties via the alteration of the Si/Al molar ratio, and maximum yields of C1-C4 compounds (60.8%) and olefins (64.7%) are achieved using a Si/Al molar ratio of 50. Additionally, metal ion exchange on H-ZSM-5 is conducted, and upgrading of PVC-containing waste-derived vapor to aromatic chemicals and small hydrocarbon molecules was successfully performed using Co-substituted H-ZSM-5. It reveals that the highest yield of gas products on 1.74 wt% cobalt (Co)-substituted H-ZSM-5 is acquired via the selection of an appropriate metal and metal ion concentration adjustment. Nevertheless, introduction of excess Co into the H-ZSM-5 surface decreases the cracking activity, thereby implying that highly distributed Co is required to achieve excellent cracking activity. The addition of Co also adjusted the acid types of H-ZSM-5, and more Lewis acid sites compared to Brønsted acid sites selectively produced olefins and naphthenes over paraffins and aromatics. The proposed approach can be a feasible process to produce valuable petroleum-replacing chemicals from Cl-containing mixed plastic wastes, contributing to the closed loops for upcycling plastic wastes.

Health of migrants and other vulnerable populations across Asian countries: Build Forward Better beyond the COVID-19 pandemic.

Global migration has been increasing since before the COVID-19 pandemic. The pandemic has clearly shown a lack of preparedness for the next public health emergency when it comes to vulnerable populations including migrants. To include the issues of migration and health in the current global health agenda, it is important to establish/strengthen a network for collaboration among various stakeholders from both the migrant-sending and host countries of migrants especially in the Asian-Pacific region. As the initial step for networking in Asia, in March 2023, a hybrid style international symposium was held in Japan and agreed on a goal and five pillars: surveillance and monitoring, risk communications, community engagement, access to health and social protection services, and supportive environments. Considering the transition of context from the COVID-19 crisis to 'Build Forward Better', through the Asian network, we will envisage the better world, where vulnerable populations including migrants will not be left behind from health security.

Association between a Marine Healing Program and Metabolic Syndrome Components and Mental Health Indicators.

Background and Objectives: Metabolic syndrome is a growing health concern globally, and its prevalence continues to increase. This study investigated whether a marine healing program could improve metabolic syndrome indicators and mental health in adults with a metabolic syndrome and those at risk of developing it. Materials and Methods: This study enrolled 30 participants who were assigned to either the experimental or control groups. The duration of the study was set at 4 weeks. Both groups received metabolic syndrome management education, and the experimental group additionally participated in two marine healing programs. Anthropometric indicators, biochemical indicators, and mental health indicators were collected before and after the intervention. Results: The findings indicate that the experimental group had significantly lower systolic blood pressure, triglycerides, and body weight, as well as higher levels of high-density lipoprotein (HDL-C) and uric acid. Mental health indicators (Hospital Anxiety and Depression Scale and quality of life measures) additionally showed improvement. Pre-post comparisons between the experimental group and the control group showed that the experimental group had significantly decreased by 1.05 kg in body weight, whereas the control group increased by 0.29 kg in body weight. In addition, HDL-C decreased by 0.91 mg/dL in the control group and increased by 3.7 mg/dL in the experimental group. Conclusions: Overall, these results suggest that marine healing programs could improve metabolic syndrome indicators such as body weight and HDL-C better than the control treatment.

Catalytic conversion of waste corrugated cardboard into lactic acid using lanthanide triflates.

The efficient strategy for waste conversion and resource recovery is of great interest in the sustainable bioeconomy context. This work reports on the catalytic upcycling of waste corrugated cardboard (WCC) into lactic acid using lanthanide triflates catalysts. WCC, a primary contributor to municipal solid wastes, has been viewed as a feedstock for producing a wide range of renewable products. Hydrothermal conversion of WCC was carried out in the presence of several lanthanide triflates. The reaction with erbium(III) triflate (Er(OTf)3) and ytterbium(III) triflate (Yb(OTf)3) resulted in high lactic acid yields, 65.5 and 64.3 mol%, respectively. In addition, various monomeric phenols were readily obtained as a co-product stream, opening up opportunities in waste management and resource recovery. Finally, technoeconomic analysis was conducted based on the experimental results, which suggests a significant economic benefit of chemocatalytic upcycling of WCC into lactic acid.

Diversity, Distribution, and Host Plant of Endophytic Fungi: A Focus on Korea.

Endophytic fungi occupy inner plant tissues, which results in various interactions between the fungus and host. Studies on endophytic fungi have been conducted in Korea for over 30 years. This paper summarizes the published results of those studies. The endophytic fungi of approximately 132 plant species in Korea have been studied since the 1990s, resulting in over 118 publications. The host plants featured in these studies comprised 3 species of mosses, 34 species of woody plants, and 95 species of herbaceous plants. At the family level, the most studied plants were members of the Poaceae family, covering 18 species. Regionally, these studies were conducted throughout Korea, but over half of the studies were conducted in Gyeongsangbuk-do, Gangwon-do, and Chungcheongnam-do. Relatively few studies have been conducted in a metropolis such as Seoul. We confirmed 5 phyla, 16 classes, 49 orders, 135 families, 305 genera, and 855 taxa of endophytic fungi, excluding Incertae sedis, whose relationship with others are unknown. Most of the endophytic fungi belonged to Ascomycota (93.2%), and a few belonged to Basidiomycota (3.6%). Since the diversity of endophytic fungi differs depending on the host plant, plant tissue, and distribution region, future studies should be conducted on multiple host plants and in various regions. Future studies on endophytic fungi are expected to broaden, including genomics and taxonomic and ecological studies of secondary metabolites.

Decomposition of naproxen by plasma in liquid process with TiO2 photocatslysts and hydrogen peroxide.

Naproxen (NPX), one of the representative non-steroidal anti-inflammatory drug (NSAID) ingredients, was decomposed by plasma in liquid process (PiLP). Strongly oxidized species generated in the plasma field of the PiLP, such as OH radicals, were confirmed by optical emission spectroscopy Increasing the operation parameters (pulse width, frequency and applied voltage) of the power supply promoted plasma field generation and OH radical generation, and affected the NPX decomposition rate. Although the NPX decomposition reaction rate was improved by up to 18-30% by adding TiO2 photocatalyst powder and H2O2 to PiLP, but the optimal addition amount should be determined considering the plasma generation and scavenger effects. A decomposition pathway was proposed, in which NPX was mineralized into CO2 and H2O through five intermediates mainly by decarboxylation, demethylation, hydroxylation, and dehydration reactions via hydroxyl radicals.

Socioeconomic disparity and the risk of contracting COVID-19 in South Korea: an NHIS-COVID-19 database cohort study.

BACKGROUND: The relationship between socioeconomic status and the risk of contracting coronavirus disease (COVID-19) remains controversial. We aimed to investigate whether socioeconomic status affected the risk of contracting COVID-19 in the South Korean population. METHODS: The NHIS-COVID-19 database cohort was used in this population-based study. We collected the data of COVID-19 patients who were diagnosed between January 1, 2020 and June 4, 2020 and those of the control population. The income levels of all individuals as of February 2020 were extracted, and study participants were classified into four groups based on quartiles: Q1 (the lowest) to Q4 (the highest). Data were statistically analyzed using multivariable logistic regression modeling. RESULTS: In total, 122,040 individuals-7669 and 114,371 individuals in the COVID-19 and control groups, respectively-were included in the final analysis. The multivariable logistic regression model showed that the Q1 group had a 1.19-fold higher risk of contracting COVID-19 than the Q4 group, whereas the Q2 and Q3 groups showed no significant differences. In the 20-39 years age group, compared with the Q4 group, the Q3 and Q2 groups showed 11 and 22% lower risks of contracting COVID-19, respectively. In the ≥60 years age group, compared with the Q4 group, the Q1, Q2, and Q3 groups showed a 1.39-, 1.29-, and 1.14-fold higher risks of COVID-19, respectively. CONCLUSIONS: Lower socioeconomic status was associated with a higher risk of contracting COVID-19 in South Korea. This association was more evident in the older population (age ≥ 60 years), whereas both lower and higher socioeconomic statuses were associated with higher risks of contracting COVID-19 in the young adult population (in the 20-39 year age group). Strategies for the prevention of COVID-19 should focus on individuals of lower socioeconomic status and on young adults of higher and lower socioeconomic status.

Stabilization of acid-rich bio-oil by catalytic mild hydrotreating.

Although liquid products derived from the pyrolysis of biomass are promising for the production of petroleum-like hydrocarbon fuels, the catalytic burden of hydrodeoxygenation must be reduced to achieve feasible upgrading processes. Herein, mild hydrotreating of an acid-rich biomass pyrolysis oil (bio-oil) with an unusually high total acid number (588 mg KOH/g bio-oil) was performed to stabilize the low-quality bio-oil. Ru-added TiO2-supported transition metal catalysts stabilized the bio-oil by reducing its acidity more compared to what could be achieved by Ru-free catalysts; this process also leads to lower loss of organic compounds compared to when using a Ru/TiO2 catalyst. Based on the performance of transition metal catalysts, including Ni, Co, and Cu, supported on TiO2, tungstate-zirconia, or SiO2, supported bimetallic catalysts were prepared by adding Ru to the TiO2-supported metal catalysts. The bimetallic catalysts Ru/Ni/TiO2 and Ru/Co/TiO2 exhibited good decarboxylation activity for the removal of carboxylic acids and a higher yield of organic compounds compared to that provided by Ru, which can be deemed appropriate for feedstocks when hydrodeoxygenation needs to suppress the loss of organic reactants. Using these catalysts, the carboxylic acid concentration was reduced to 319-323 mg KOH/g bio-oil with organic yields of 62-63 wt% at reaction temperatures 150-170 °C lower than the temperature required for direct conversion of carboxylic acids to alcohols or deoxygenates. The improved catalytic hydrotreating activity of Ru-added transition metals can be attributed to the high acid site densities of these catalysts along with their improved hydrogenation activities.

Improved catalytic depolymerization of lignin waste using carbohydrate derivatives.

CARBOHYDRATE-: or sugar-derived compounds were used as environmentally friendly additives for the depolymerization of Kraft lignin waste and organosolv lignin prepared from Miscanthus giganteus. The yields of the aromatic monomers obtained from Kraft lignin increased from 5.1 to 49.2% with the addition of mannitol, while those obtained from organosolv lignin increased from 44.4 to 83.0% with the addition of sucrose. This improved lignin depolymerization was also confirmed by gel permeation chromatography and nuclear magnetic resonance spectroscopy. The above results clearly indicate the beneficial effects of carbohydrate derivatives on the lignin depolymersization process, more specifically, suggesting that the presence of carbohydrates improve the lignin depolymerization of lignocellulose, as observed for the raw lignocellulose feed.

The Relationship between Risk Perception of Cell Phones and Objective Knowledge of EMF in Korea.

This study examines differences between the level of objective knowledge regarding radio-frequency electromagnetic fields (RF-EMF) and risk perception of cell phones in Korea. We also investigate the extent to which socio-demographic factors, perceived EMF exposure, objective knowledge regarding EMF, and psychological factors influence the risk perception of cell phones using hierarchical multiple regression. All 3393 study subjects completed a survey measuring the degree of risk perception of EMF. They were sampled in accordance with representative proportions of sex, age group, and region of residence as shown in the 2019 Resident Registration Population Statistics reported by Korea. The variables that have the most influence on risk perception of cell phones can be induced from the beta values for each variable: The subjective factor, perceived level of exposure to EMF (ß = 0.253), was more strongly related to risk perception of cell phones than level of knowledge regarding EMF, an objective factor in this study. Of the psychological factors, Dreadfulness (ß = 0.331), Personal knowledge (ß = -174), and Familiarity (ß = -089) influenced risk perceptions of cell phones; Controllability did not. On the risk cognition map, people though that it was easy to control risk related to Cell phone use in daily life, while risk related to High technology was uncontrollable.

SiO2@MnO x @Na2WO4@SiO2 core-shell-derived catalyst for oxidative coupling of methane.

SiO2@MnO x @Na2WO4@SiO2 core-shell catalysts were prepared and their fabrication was confirmed using transmission electron microscopy. The formation of Mn-based nanosheets on the silica spheres is important for the deposition of nanoscopic Na2WO4. The SiO2@MnO x @Na2WO4@SiO2 core-shell catalysts were used for the oxidative coupling of methane at a temperature of 700-800 °C at which the nanostructures were completely destroyed. Although the core-shell structures did not survive the high-temperature oxidative coupling of methane, the selective production of olefins and paraffins can be attributed to highly dispersed Na2WO4 derived from confined core-shell structures.

Study on the unsteady state oxidative coupling of methane: effects of oxygen species from O2, surface lattice oxygen, and CO2 on the C2+ selectivity.

This study examined the effects of oxygen species on the unsteady-state oxidative coupling of methane (OCM) using a lengthy catalyst bed of Na2WO4/Mn/SiO2. The reaction conditions, including the methane-to-oxygen ratio, ratio of feed gas dilution by N2, quantity of catalyst, and feed flow rate were adjusted for the continuous flow fixed bed reaction system. While the O2 gas initiated methyl radical formation from methane, the surface lattice oxygen atoms improved the dehydrogenation of paraffins to olefins without significant activation of methane. The addition of CO2 as a mild oxidizing agent was also tested and slightly improved OCM selectivity with slightly lower methane conversion were observed.

Highly Dispersed Pt Nanoparticles for the Production of Aromatic Hydrocarbons by the Catalytic Degrading of Alkali Lignin.

Aromatic hydrocarbons were produced from lignin, a complex natural amorphous polymer commonly regarded as by-product of the pulping process and from biofuel production. The catalytic decomposition of lignin using supported Pt catalysts was performed to produce small molecule hydrocarbons. Aromatic small-molecule hydrocarbon products were identified and quantified using GC/MS and GC-FID, which demonstrated that 27.6% of aromatic hydrocarbons were obtained from the activated carbon-supported Pt (Pt/AC) catalyst which had the highest Pt surface area.

Catalytic Depolymerization of Alkali Lignin Using Supported Pt Nanoparticle Catalysts.

Alkali lignin, a byproduct of the pulping process, was depolymerized using Pt nanoparticle catalysts. A depolymerized lignin with a lower molecular weight was obtained and characterized with GPC and NMR. 31P-NMR using OH-sensitive probing molecules showed the formation of guaiacyl OHs during the reaction, indicating the cleavage of guaiacyl ether bonds.

Effects of Current-injection Firing with Ag Paste in a Boron Emitter.

A high contact resistance for screen-printed contacts was observed when a conventional Ag paste was used on a boron emitter. The results of this study suggest that electron injection during firing is one of the processes that contribute to a lower contact resistance. Larger quantities of Ag precipitates formed upon electron injection into the boron emitter, which was confirmed by observing Ag crystallite or dendrite structures on the boron and by measuring the contact resistance between the boron emitter and the Ag bulk. The electron-injected sample had approximately 10000 times lower contact resistance than an untreated sample. The contact resistance of the electron-injected sample was 0.021 mΩ âˆ™ cm(2) under optimal conditions, which is lower than that of conventional p-type silicon solar cells. Thus, electron injection can effectively lower contact resistance when using Ag paste in n-type silicon solar cells. During the cooling in the firing process, dissolved Ag ions in the glass layer are formed as dendrites or crystallites/particles. The dendrites are formed earlier than others via electrochemical migration under electron injection conditions. Then, crystallites and particles are formed via a silicon etching reaction. Thus, Ag ions that are not formed as dendrites will form as crystallites or particles.

Effects of artificial light at night on human health: A literature review of observational and experimental studies applied to exposure assessment.

It has frequently been reported that exposure to artificial light at night (ALAN) may cause negative health effects, such as breast cancer, circadian phase disruption and sleep disorders. Here, we reviewed the literature assessing the effects of human exposure to ALAN in order to list the health effects of various aspects of ALAN. Several electronic databases were searched for articles, published through August 2014, related to assessing the effects of exposure to ALAN on human health; these also included the details of experiments on such exposure. A total of 85 articles were included in the review. Several observational studies showed that outdoor ALAN levels are a risk factor for breast cancer and reported that indoor light intensity and individual lighting habits were relevant to this risk. Exposure to artificial bright light during the nighttime suppresses melatonin secretion, increases sleep onset latency (SOL) and increases alertness. Circadian misalignment caused by chronic ALAN exposure may have negative effects on the psychological, cardiovascular and/or metabolic functions. ALAN also causes circadian phase disruption, which increases with longer duration of exposure and with exposure later in the evening. It has also been reported that shorter wavelengths of light preferentially disturb melatonin secretion and cause circadian phase shifts, even if the light is not bright. This literature review may be helpful to understand the health effects of ALAN exposure and suggests that it is necessary to consider various characteristics of artificial light, beyond mere intensity.

A Vanadium Dioxide Metamaterial Disengaged from Insulator-to-Metal Transition.

We report that vanadium dioxide films patterned with λ/100000 nanogaps exhibit an anomalous transition behavior at millimeter wavelengths. Most of the hybrid structure's switching actions occur well below the insulator to metal transition temperature, starting from 25 °C, so that the hysteresis curves completely separate themselves from their bare film counterparts. It is found that thermally excited intrinsic carriers are responsible for this behavior by introducing enough loss in the context of the radically modified electromagnetic environment in the vicinity of the nanogaps. This phenomenon newly extends the versatility of insulator to metal transition devices to encompass their semiconductor properties.

Mobile phone use and risk of glioma: a case-control study in Korea for 2002-2007.

OBJECTIVES: There has been a growing concern about the possible carcinogenic effects of the electromagnetic radiofrequency fields emitted from mobile phones. The purpose of this study was to investigate the association between mobile phone use and the development of gliomas in Korea. METHODS: Our study methods were based on the International Interphone study that aimed to evaluate possible adverse effects of mobile phone use. This study included 285 histologically-confirmed Korean patients 15 to 69 years of age, with gliomas diagnosed between 2002 and 2007 in 9 hospitals. The 285 individually matched controls were healthy individuals that had their medical check-up in the same hospitals. Unconditional logistic regression was used to calculate the adjusted odds ratios (aORs) and 95% confidence intervals (CIs) for use of mobile phones. RESULTS: For the entire group, no significant relationship was investigated between gliomas and regular use of mobile phones, types of mobile phones, lifetime years of use, monthly service fee, and the other exposure indices. Analyses restricted to self-respondents showed similar results. For ipsilateral users, whose the body side for usual mobile phone use match the location of glioma, the aORs (95% CIs) for lifetime years of use and cumulative hours of use were 1.25 (0.55 to 2.88) and 1.77 (0.32 to 1.84), respectively. However, the contralateral users showed slightly lower risk than ipsilateral users. CONCLUSIONS: Our results do not support the hypothesis that the use of mobile phones increases the risk of glioma; however, we found a non-significant increase in risk among ipsilateral users. These findings suggest further evaluation for glioma risk among long-term mobile phone users.

Blood cadmium concentration of residents living near abandoned metal mines in Korea.

The purpose of this study was to investigate demographic and lifestyle variables and blood cadmium concentrations in residents living near abandoned metal mines in Korea. Blood cadmium concentrations were measured in 15,161 subjects living around abandoned metal mines (exposed group, n = 14,464) and compared with those living in designated control areas (control group, n = 697). A questionnaire was provided to all subjects to determine age, gender, mine working history, times of residence, smoking habits and dietary water type. The geometric mean (95% confidence intervals) of blood cadmium concentration (1.25 [1.24-1.27] µg/L) in the exposed group was significantly higher than in the control group (1.17 [1.13-1.22] µg/L). Mean residence time and mine working history in the exposed group were significantly higher than in the control group. Blood cadmium concentrations increased with increasing age, and residence time in both groups, and blood cadmium concentrations were higher in current-smokers than in non-smokers in both groups. This study shows the geometric mean of blood cadmium concentration in abandoned mining areas are higher than in non-mining areas in the general adult Korean population.

Association of arsenic levels in soil and water with urinary arsenic concentration of residents in the vicinity of closed metal mines.

Arsenic (As) pollution in the surroundings of metal mines has been observed, and may induce serious health problems, in particular cancer. Health hazard attributed to As in contaminated soil and water in the vicinity of closed or abandoned metal mines may be high. Little is known about how environmental exposure to As has affected the health of resident near closed metal mines. The objectives of this study were to compare the urinary level of As for those living near closed metal mines (the exposed group) with that of non-exposed group; and to investigate the correlation between As levels in soil (SoilAs) and water (WaterAs) and the urinary levels (UrineAs) of residents in the exposed group. Data for SoilAs and WaterAs were obtained from the national environmental survey performed between 2003 and 2005 by the Ministry of Environment in Korea. To measure UrineAs, 2674 and 237 subjects were selected from 67 closed metal mines (exposed areas) and two rural areas (non-exposed areas), respectively. Five milliliters of urine samples were taken, and graphite furnace atomic absorption spectrometry was used to analyze UrineAs. Of all the exposed areas, high SoilAs and WaterAs areas that exceed the Korean standards of As in soil (6 mg/kg-soil) and stream or groundwater (0.05 mg/l-water) were classified to evaluate the health risks in high polluted areas. Also, high UrineAs group was defined as 20 µg/g creatinine or more. Student's t-test was performed to compare the UrineAs level between the exposed and non-exposed groups. The odds ratio (OR) was calculated by a logistic analysis to evaluate the risk for high UrineAs level from high SoilAs and WaterAs areas. The mean of urinary As were 8.90 ± 8.34 µg/g-creatinine for the exposed group and 7.68 ± 4.98 µg/g creatinine for the non-exposed group, respectively; and the significant difference of urinary As level was observed between both groups (p<0.05). Moreover, the means for urinary As of people in areas with high As level in soil and water were significantly higher than that for the control areas (p<0.001), and these differences were more pronounced for the As level in water. The odds of subjects with high UrineAs were positively and significantly associated with living in the areas with high As level in soil (OR=1.62; 95% C.I.=1.13-2.31). These associations were much stronger for the areas with high WaterAs (OR=3.79; 95% C.I.=2.32-6.19). These results indicate that the high level of As in environment may increase the risk of having high urinary As level of people in the exposed areas.