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Cylindrospermopsin (CYN) is an emerging freshwater cyanobacterial toxin, and its reports on toxicity toward the human liver and kidney tissues has drawn a lot of attention. An appropriate analytical method is necessary to determine the presence of this emerging cyanobacterial toxin in water resources including drinking water; therefore, it is necessary to develop a sensitive analytical method for CYN detection. In this study, we developed a simple and sensitive analytical method for CYN detection using liquid chromatography-tandem mass spectrometry (LC-MS/MS) using direct injection. The method was validated for linearity of calibration, limit of detection, limit of quantitation, accuracy, and precision. The limit of detection and quantitation were in the range of 0.029 μg/L and 0.091 μg/L, respectively. Accuracy and precision were also obtained within an acceptable range. The optimized method was used to measure the concentrations of CYN in the surface water from each weir areas of the Geum River, Nakdong River. Additionally, this method was applied to samples of drinking water obtained from the treatment plants of the Geum River, Nakdong River for each process.

β-Methylamino-L-alanine (BMAA) is an emerging algal toxin that has drawn attention because it can cause neurodegenerative diseases, including Parkinson's disease and Alzheimer's disease (AD). Therefore, it is necessary to develop a sensitive analytical method for BMAA, an emerging cyanobacterial toxin, to determine whether a trace amount is detected in the water resources and treated water. In this study, we developed a simple and sensitive analytical method for BMAA using liquid chromatography-tandem mass spectrometry (LC-MS/MS) with direct injection. The method was validated for linearity of calibration, limit of detection, limit of quantitation, accuracy, and precision. The limits of detection and quantitation were in the range of 0.030 ?/L and 0.096 ?/L, respectively. The optimized method was used to measure the concentrations of BMAA in surface water from each weir point of the Geum River, Nakdong River. Sampling and analysis of drinking water treatment plants of the Geum River, Nakdong River were applied to samples for each process.

Following the outbreak of the COVID-19 pandemic, the continued emergence of major variant viruses has caused enormous damage worldwide by generating social and economic ripple effects, and the importance of PHSMs (Public Health and Social Measures) is being highlighted to cope with this severe situation. Accordingly, there has also been an increase in research related to a decision support system based on simulation approaches used as a basis for PHSMs. However, previous studies showed limitations impeding utilization as a decision support system for policy establishment and implementation, such as the failure to reflect changes in the effectiveness of PHSMs and the restriction to short-term forecasts. Therefore, this study proposes an LSTM-Autoencoder-based decision support system for establishing and implementing PHSMs. To overcome the limitations of existing studies, the proposed decision support system used a methodology for predicting the number of daily confirmed cases over multiple periods based on multiple output strategies and a methodology for rapidly identifying varies in policy effects based on anomaly detection. It was confirmed that the proposed decision support system demonstrated excellent performance compared to models used for time series analysis such as statistical models and deep learning models. In addition, we endeavored to increase the usability of the proposed decision support system by suggesting a transfer learning-based methodology that can efficiently reflect variations in policy effects. Finally, the decision support system proposed in this study provides a methodology that provides multi-period forecasts, identifying variations in policy effects, and efficiently reflects the effects of variation policies. It was intended to provide reasonable and realistic information for the establishment and implementation of PHSMs and, through this, to yield information expected to be highly useful, which had not been provided in the decision support systems presented in previous studies.

Among many contaminants of emerging concern, perfluorooctanesulfonate (PFOS) is widely known as one of the most difficult to decompose due to a very strong carbon-fluorine bond. Electron beam technology has been used to treat refractory compounds as a radical-based advanced oxidation process. Therefore, the aims of this study were to investigate the degradation efficiencies of PFOS with various initial concentrations and radiolytic products generated by PFOS decomposition using an electron beam, to improve the decomposition efficiency of PFOS using combined persulfate (S2O82−) and hydrogen peroxide (H2O2) with an electron beam, and to propose the radiolysis decomposition pathway of PFOS in aqueous solution. The results showed that the degradation efficiency of PFOS by the electron beam depended on the initial PFOS concentration. The addition of S2O82− with the electron beam increased the decomposition efficiency with increasing absorbed doses. The 0.1 mg/L PFOS (0.19 µM) in the presence of 5 mM S2O82− with the electron beam at a 100 kGy absorbed dose had a similar decomposition efficiency with that using only the electron beam at a 900 kGy absorbed dose. However, the addition of H2O2 was ineffective on the PFOS degradation in aqueous solution. Seven radiolytic products such as perfluorocarboxylic acids (PFCAs) were quantitatively confirmed using authentic standards among eight predicted radiolytic products. The radiolysis decomposition of PFOS can occur spontaneously in aqueous solution with the synergistic effects of e aq - and OH produced by electron beam irradiation. Therefore, the electron beam can be used as a viable process considering the decomposition efficiency and its degradation products.

Background Although warfarin is highly effective, management of patients prescribed warfarin is complex due to its narrow therapeutic window. Objective To evaluate the impact of a formal warfarin discharge education program (WDEP) on hospital readmission and treatment costs in patients who received warfarin therapy. Setting Robert Wood Johnson University Hospital Somerset in Somerville, New Jersey, USA. Method In this interventional cohort study, patients were assigned to either the WDEP group or the usual care group. The effects of the WDEP on readmission within 90 days after discharge were analyzed using Cox proportional hazards models. Factors influencing treatment cost were identified using generalized linear model with log-link function and gamma distribution. Main outcome measure Hospital readmission within 90 days and treatment costs associated with hospital readmission. Results Among 692 eligible patients, 203 in each group were matched using propensity scores and there were no statistically significant differences in the patient baseline characteristics between two groups. The risk of all-cause readmission within 90 days was significantly lower in the WDEP group compared to the usual care group (relative risk = 0.46, 95% CI 0.28-0.76). The treatment costs associated with hospital readmission in the WDEP group were 19% lower than those in the usual care group after adjusting for the study variables. Conclusion A formal, individualized WDEP provided by pharmacists resulted in significant reduction of readmission and treatment costs. The economic burden of treatment costs associated with warfarin can be controlled if well-organized warfarin education is provided to patients who received warfarin therapy.

The environment has been continuously exposed to heavy metals by various routes, from both natural and artificial sources. In particular, heavy metals in water can affect aquatic organisms adversely, even at very low concentrations, and can lead to the disturbance of the ecosystem balance and biodiversity. Ecological risk assessments are conducted to protect the environment from such situations, primarily by deriving the predicted no-effect concentration (PNEC) from the species sensitivity distribution (SSD). This study developed the SSDs based on the species living in Korean freshwater for four heavy metals including cadmium (Cd), copper (Cu), lead (Pb), and zinc (Zn). The species compositions of the SSDs were examined, and three types of PNECs were derived by applying different assessment factors (AF). In addition, the occurrence and concentrations of heavy metals in Korean rivers were investigated, and the ecological risk assessment was carried out to compare the SSDs with the environmental concentrations. The SSDs were developed using a sufficient number of species, but the missing data of plants and insects provided an incomplete species composition. The results show that Cd and Pb in the environmental concentrations of rivers would not cause any risk to aquatic organisms from the derived PNEC. However, some organisms might be adversely affected by the concentrations of Zn, and a small amount of risk was expected under the conservative PNEC. The distribution of Cu in the rivers was not considered to be safe for aquatic organisms because the average environmental concentrations potentially affected the proportion of the SSD, and the environmental concentrations exceeded the PNECs. The concentrations of Cu and Zn in industrial waters indicated a considerable risk to aquatic organisms, and the probability of exceeding the PNECs appeared to be quite high. Therefore, this study indicates that additional actions and parallel field studies are required based on the risk posed to aquatic organisms by Cu and Zn in four Korean rivers.

Toxicity identification evaluation (TIE) was applied to the effluent from a pharmaceutical industrial complex, following the US EPA TIE guidelines. The whole effluent toxicity (WET) test found toxicity greater than 16toxic units (TU) in the effluent. Dissolved non-polar organic compounds were identified as the major contributor to the observed toxicity in the TIE manipulations in phases I and II. Among the 48 organic compounds identified, three compounds (i.e., acetophenone, benzoimide, and benzothiazole) were related to the pharmaceutical production procedure; however, no contribution to toxicity was predicted in the compounds. The results of the ECOSAR model, which predicts toxicity, indicated that the alkane compounds caused significant toxicity in the effluent. The toxicity test and heavy metal analysis, which used IC and ICP/MS, identified that particulate and heavy metals, such as Cu and Zn, contributed to the remaining toxicity, except dissolved organics. The results showed the applicability of the TIE method for predicting regional effluents produced by the industrial pharmaceutical complex in this study. Although the location was assumed to be affected by discharge of pharmaceutical related compounds in the river, no correlations were observed in the study. Based on the results, advanced treatment processes, such as activated carbon adsorption, are recommended for the wastewater treatment process in this location.

This study investigates the use of selected ion flow tube mass spectrometry with an automated headspace pretreatment system for the continuous surveillance of water quality at wastewater treatment plants (WWTPs) and rivers. The reaction rates of the target compounds introduced using the headspace method were similar to those of the mass scan library, with a margin of error of &lt, 10%. Novel quantitative formulae were derived for the water samples of the target compounds, and the linearity of the calibration curves for both the purified and effluent matrix (0.1&ndash, 2.0 mg/L) showed a coefficient of determination of 0.98&ndash, 0.99 for most compounds. The detection limit for 74% of the target substances was 0.02&ndash, 0.10 mg/L, and the average recoveries were 111.6% and 104.7% for the low- and high-concentration spiked samples, respectively, which are comparable to those of the headspace gas chromatography-mass spectrometry system. However, the variability in individual concentrations was still large, due to the unstable control of sample injection flow and pressure. Herein, 79% of the 28 compounds met one-tenth of the proposed method detection limit criteria for emergency operations in WWTP. Field experiments showed that the system was easy to maintain and could be used to monitor chemical accidents.

Increasing evidence suggests that the toxicity of fine dust particles (PM2.5) is linked to specific components rather than their mass. However, research on the chemical composition and health risk of PM2.5 is insufficient. This study analyzed the metals, polycyclic aromatic hydrocarbon (PAHs), organochlorine pesticides (OCPs), and polychlorinated biphenyls (PCBs) present in PM2.5 and evaluated their risk to health during outdoor activities. The concentration of metals was one order of magnitude higher than that of PAHs and the concentration and detection frequency of OCPs and PCBs were considerably lower than those of metals and PAHs. The lifetime excess cancer risk (LECR) for carcinogens in PM2.5 exceeded de minimis risk (1 × 10−6) as 1.33–3.44 × 10−6 (at 5th–95th percentile) as Cr(VI), As, and Cd showed high contributions. Children in the 2

Studies investigating toxic organic pollutants in fine dust (PM2.5), such as polycyclic aromatic hydrocarbons (PAHs), organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs), are insufficient, despite the pollutants’ potent toxicity. The objective of this study is to develop an analytical method for determining PAHs, OCPs and PCBs in ambient PM2.5 using selective pressurized liquid extraction (SPLE). To maximize the extraction efficiency of target analytes, the extraction parameters of SPLE, particularly solvent type, temperature, static time, and cycle number, were optimized. The highest recoveries were observed under the conditions of dichloromethane:acetone (9:1), 100℃, 5 min of static time, and 1 cycle extraction, which is selected as the optimal method of SPLE. In the method validation, the results showed that the suggested method can quantify 17 PAHs, 20 OCPs, and 63 PCBs in PM2.5. Using urban dust SRM (1648a) and ambient PM2.5 samples, the applicability of the method was also confirmed. Total concentration of PAHs was the highest (2639.42–7377.75 pg/m3) followed by OCPs (80.57–674.69 pg/m3) and PCBs (1.39–9.34 pg/m3). Most of the PAHs were detected, whereas 2–7 compounds among 20 OCPs and 2–6 compounds among 63 PCBs were determined. The developed analytical method is highly efficient in terms of process (a one-step extraction process), time (15 min extraction time per one sample) and solvent usage (less than 30 mL per one sample), showing good performance. This method can be applied to investigate the organic toxicants in PM2.5, and it can contribute to monitoring and risk assessment, leading to an effective risk management policy for PM2.5 in Korea.

Because of their persistence, bioaccumulation tendency, and toxicity, organochlorine pesticides (OCPs) were banned several decades ago. However, they are still detected in natural water and pose a serious risk to human health and the environment. In the present study, seven OCPs were measured in river water collected from 28 sampling sites between 2010 and 2011 in the Yeongsan (YS) and Seomjin (SJ) Rivers, Korea. Gas chromatography/high-resolution mass spectrometry (HRMS) was used for the chemical analysis. The potential health risks of consuming OCPs in fish were assessed in the monitoring region (YS and SJ River basins) by measuring the residual level of OCPs. The human health risks were characterized by considering both the exposure level and the corresponding cancer slope factors; we incorporated both deterministic and probabilistic approaches. The risks were calculated using the probabilistic Maximum Likelihood Estimation (MLE) method. Risk uncertainty and sensitivity were calculated by performing a Monte Carlo analysis. Of the six OCPs, dieldrin, heptachlor epoxide, and hexachlorobenzene exceeded the acceptable risk level in the heavy and light fish consumer groups. The cancer risks associated with these OCPs were 2.99 × 10 −6 , 5.81 × 10 −6 and 3.72 × 10 −6 , respectively, using the deterministic approach and 1.64 × 10 −5 , 3.36 × 10 −2 and 5.52 × 10 −5 , respectively, at the 95th percentile using the probabilistic approach. Because there is a high cancer risk associated with these three OCPs, individuals who consume large amounts of freshwater fish may be subject to a high risk of cancer. However, the calculations may have over- or underestimated the risk because of the uncertainty of the environmental concentration and fish intake rate or the use of left-censored monitoring data.

Dye-sensitized solar cells (DSSCs) were fabricated using TiO2 nanoparticles (NPs), TiO2 nanotube arrays (NTAs), and surface-modified NTAs with a TiCl4 treatment. The photovoltaic efficiencies of the DSSCs using TiO2 NP, NTA, and TiCl4-treated NTA electrodes are 4.25, 4.74, and 7.47 %, respectively. The highest performance was observed with a TiCl4-treated TiO2 NTA photoanode, although in the case of the latter two electrodes, the amounts of N719 dye adsorbed were similar and 68 % of that of the NP electrode. Electrochemical impedance measurements show that the overall resistance, including the charge–transfer resistance, was smaller with NTA morphologies than with NP morphologies. We suggest that a different electron transfer mechanism along the one-dimensional nanostructure of the TiO2 NTAs contributes to the smaller charge–transfer resistance, resulting in a higher short circuit current (J sc), even at lower dye adsorption. Furthermore, the TiCl4-treated NTAs showed even smaller charge–transfer resistance, resulting in the highest J sc value, because the downward shift in the conduction band edge improves the electron injection efficiency from the excited dye into the TiCl4-treated TiO2 electrodes.

We demonstrate the synthesis of CdS-sensitized TiO2 (CdS/TiO2) nanotube arrays via the solvothermal method and describe their enhanced photoelectrochemical properties. Our new approach prevents the clogging of CdS quantum dots (QDs) at the TiO2 nanotube mouth and promotes the uniform deposition of a polycrystalline CdS on the densely aligned TiO2 nanotube arrays (TiO2 NTAs). The deposition of CdS onto the TiO2 NTA can be controlled by the deposition time and the concentration of the precursors. Photoelectrochemical measurements indicate that the electrode synthesized via the solvothermal method can achieve a stable photocurrent density of 5.7 mA/cm2 at 0-V versus Ag/AgCl under AM 1.5 G illumination, which is approximately 10% higher than that prepared using the chemical bath deposition (CBD) method. Solvothermally prepared CdS/TiO2 NTAs exhibit 125-fold enhancement in their photocurrent under visible light compared with bare TiO2 NTAs, indicating facile photogenerated electron transfer from CdS to TiO2. Solvothermally prepared CdS/TiO2 NTAs shows better photostability and longer lifetime of photoelectrons compared to those prepared by CBD method suggesting more favorable CdS–TiO2 NTA interfacial contact. In general, we propose that this methodology can be useful in designing multijunction semiconductor configuration such as coating nanostructures.

Water quality impairment from nonpoint source pollution is one of the critical causes of surface water eutrophication in rivers and lakes surrounding agricultural area, Korea. In the Songchon Constructed Wetland (SCW) located in Yeongsan (YS) watershed which has about 1,000 km2 (total watershed area: 3,471 km2) for agricultural area, 19 times of intensive field monitoring in 2010 were conducted with various rainfall patterns and about more 1,000 water samples were measured and analyzed in field and laboratory. To identify the relationship between meteorological conditions and removal efficiency of the constructed wetland, principal component analysis (PCA) and ternary plot analysis was used for 19 field experiment data. Mean treatment performance of TSS, BOD5, COD, TN, and TP was 16.4%, 42.1%, 43.7%, 36.6%, and 57.1%, respectively, as a method of pollutant load reduction for multiple tests of storm events. PCA results revealed that rainfall depth, rainfall intensity, and antecedent dry days (ADDs) can be major components as a representative in each component. Also, ternary contour plots results showed that the treatment performance of SCW in agricultural area during storm events can be affected by three meteorological conditions. These results and phenomena can be applicable to develop the NPS discharge model and to elucidate the relationship between rainfall and storm water runoff using rain radar in a drainage area.

Broad scale monitoring of estrogenic compounds was performed at 19 sampling points throughout the Yeongsan and Seomjin river basins and 5 wastewater treatment plants (WWTPs) adjacent to the Gwangju area, Korea, from December 2005 to August 2007. The concentrations of estrogenic compounds, including estrone (E1), 17β-estradiol (E2), 17α-ethynylestradiol (EE2), bisphenol-A, nonylphenol (NP) and 4-octylphenol (OP), in the samples was measured with gas chromatography/mass spectrometry (GC-MS). In addition, the estrogenic activities throughout the river were investigated using the E-screen assay. Of the six estrogenic chemicals, NP (114.6-336.1 ng L(-1)) and EE2 (0.23-1.90 ng L(-1)) were detected at the highest and lowest levels, respectively in both the river waters and the WWTP effluents. Bisphenol-A showed the largest concentration range, from 7.5 to 335 ng L(-1). The concentrations of E1, E2 and octylphenol ranges were 3.6-69.1, 1.2-10.7, and 2.2-16.9 ng L(-1), respectively. According to the calculated estradiol equivalent concentration (EEQ); however, no estrogenic contribution was observed due to the phenolic compounds in the river waters and effluents. E1 and E2 dominated in both the river water and effluent samples, with contributions to the calculated EEQ of over 79 and 77%, respectively. Conversely, EE2 was rarely detected in the river waters (21%) and effluents (0%). The largest contribution of EE2 to the calculated EEQ was 21% in the river water at S-7. The levels of E1, E2, and EE2 were remarkably decreased in the effluents, indicating that the 5 WWTPs did not contribute to the estrogenic effect of the receiving streams. Overall, the WWTPs did not contributed to the estrogenic activity of the receiving waters, but the livestock industry or wildlife may play an important role in the estrogenic contribution to river water.

In the cam mechanism, the problem of surface fatigue or wear becomes more severe at contact point between cam and roller follower. The more fatigue or wear is, the less the lifetime is. As well as it leads to loss of engine performance, so to reduce the surface fatigue or wear is the primary problem to solve. In this paper, a general polynomial function developed by Thoren, Engemann, and Stoddart (TES) with real values of exponents is selected and genetic algorithm (GA) is used to decrease the surface fatigue by minimizing the wear rate proportional factor (WRPF) since they vary directly. Therefore, an attempt of this paper has been made to minimize the maximum value of WRPF using GA as the optimization program. And the results show that the minimum the maximum WRPF can be lowered approximately 10% in this paper.

Toxicity changes in copper and diazinon were investigated in the presence of food, clay, and their mixture by using Daphnia magna. In sorption equilibrium experiments, copper was significantly attracted (>34% sorbed) to food, clay, and food-clay mixture due to their negative zeta potential, while diazinon was less sorbed (