Уточнить поиск
Результаты 3781-3790 из 5,153
A novel WO3 sonocatalyst for treatment of rhodamine B under ultrasonic irradiation Полный текст
2018
Li, Tongtong | Song, Limin | Zhang, Shujuan
Pure WO₃ powder was prepared from a simple method and applied into sonocatalytic degradation of rhodamine B (RhB), the model compound. The structure and properties of samples were characterized by X-ray diffractometry (XRD), transmission electron microscopy (TEM), ultraviolet–visible (UV–vis) absorption spectroscopy, and photoluminescence (PL) spectroscopy. We studied the effects of WO₃ on the sonocatalytic degradation of RhB and the operational parameters such as catalyst dosage and RhB concentration. The experimental results showed that the best sonocatalytic degradation ratio (59.39%) of organic dyes could be obtained when the optimal conditions of 10.00-mg/L initial concentration, 3.00-g/L prepared WO₃ powder added amount, 99-W ultrasound output power, and 270-min ultrasonic irradiation were adopted. Under ultrasonic conditions, the degradation rate after addition of WO₃ reached the highest activity of 57.9%, and about three times the rate of degradation was not added. Abundant ·OH was induced by WO₃ powder under ultrasonic irradiation, which may be the main contributor to the high sonodegradation rate.
Показать больше [+] Меньше [-]Correction to: Community reporting of ambient air polychlorinated biphenyl concentrations near a Superfund site Полный текст
2018
Tomsho, Kathryn S. | Basra, Komal | Rubin, Staci M. | Miller, Claire B. | Juang, Richard | Broude, Sylvia | Martinez, Andres | Hornbuckle, Keri C. | Heiger-Bernays, Wendy | Scammell, Madeleine K.
The original version of this article unfortunately contains a mistake. The correct Author names should be Staci M. Rubin and Keri C. Hornbuckle.
Показать больше [+] Меньше [-]Critical analysis of excessive utilization of crude protein in ruminants ration: impact on environmental ecosystem and opportunities of supplementation of limiting amino acids—a review Полный текст
2018
Abbasi, ImtiazHussain Raja | Abbasi, Farzana | Abd El-Hack, MohamedE. | Abdel-Latif, MervatA. | Soomro, RabN. | Hayat, Khawar | Mohamed, MohamedA. E. | Bodinga, BelloM. | Yao, Junhu | Cao, Yangchun
Protein quality plays a key role than quantity in growth, production, and reproduction of ruminants. Application of high concentration of dietary crude protein (CP) did not balance the proportion of these limiting amino acids (AA) at duodenal digesta of high producing dairy cow. Thus, dietary supplementation of rumen-protected AA is recommended to sustain the physiological, productive, and reproductive performance of ruminants. Poor metabolism of high CP diets in rumen excretes excessive nitrogen (N) through urine and feces in the environment. This excretion is usually in the form of nitrous oxide, nitric oxide, nitrate, and ammonia. In addition to producing gases like methane, hydrogen carbon dioxide pollutes and has a potentially negative impact on air, soil, and water quality. Data specify that supplementation of top-limiting AA methionine and lysine (Met + Lys) in ruminants’ ration is one of the best approaches to enhance the utilization of feed protein and alleviate negative biohazards of CP in ruminants’ ration. In conclusion, many in vivo and in vitro studies were reviewed and reported that low dietary CP with supplemental rumen-protected AA (Met + Lys) showed a good ability to reduce N losses or NH₃. Also, it helps in declining gases emission and decreasing soil or water contamination without negative impacts on animal performance. Finally, further studies are needed on genetic and molecular basis to explain the impact of Met + Lys supplementation on co-occurrence patterns of microbiome of rumen which shine new light on bacteria, methanogen, and protozoal interaction in ruminants.
Показать больше [+] Меньше [-]A device-specific prioritization strategy based on the potential for harm to human health in informal WEEE recycling Полный текст
2018
Cesaro, Alessandra | Belgiorno, V. | Vaccari, Mentore | Jandric, Aleksander | Chung, TranDuc | Dias, MariaIsabel | Hursthouse, Andrew | Salhofer, Stefan
In developing countries, the recovery of valuable materials from Waste Electrical and Electronic Equipment (WEEE) is carried out via uncontrolled practices, posing potentially severe risks both to human health and the environment. The assessment of the risk, which depends on both the kind and hazardous properties of the substances contained in WEEE, is currently limited as the exposure scenario for the single informal practice cannot be fully characterized for this purpose. In this context, this work proposes and evaluates a strategy to identify the relative potential harm of different kinds of WEEE by their content in metals, selected as the target substances of concern. This was based on the individual metal content, primarily located in the printed circuit boards (PCBs) of the different devices. The metal composition of the individual PCBs was identified and the dominant unregulated metal recovery practices were reviewed to identify the most suitable parameter to express the toxicity of these metals. Based on a mass-normalized cumulative toxicity, via the inhalation route, individual components were assessed from compositional variation found in the literature. The results is a semiquantitative ranking of individual components, revealing significant differences in potential harm posed by different electronic appliances and an opportunity to provide prioritization strategies in future management.
Показать больше [+] Меньше [-]Improving Cu(II) sorption by biochar via pyrolyzation under CO2: the importance of inherent inorganic species Полный текст
2018
Wen, Ran | Yuan, Bo | Wang, Yang | Cao, Weimin | Liu, Yuan | Jia, Yi | Liu, Qiang
Biochar from Spartina alterniflora (SA) and rice straw (RS) under N₂/CO₂ were evaluated for Cu(II) removal from aqueous solution. The result indicates SA biochar prepared at 700 °C under CO₂ can achieve a Cu(II) sorption capacity of 89.12 ± 2.77 mg/g, which is higher than that from N₂ by about 50%. CO₂ can promote the development of multi-porous structure, enhance specific surface area, and increase the amounts of hydroxyl and carboxyl groups on biochar. In addition, CO₂ can inhibit the thermal decomposition of inorganic carbonate, such as MgCO₃ and CaCO₃ in biochar. These matters facilitate Cu(II) removal via the formation of chemical precipitation of Cu₂(OH)₂CO₃. The dissolution of inherent inorganic matter makes Cu(II) transformed into hydrolyzed species or amorphous precipitation, which contributes to about 75% (w/w) of Cu(II) removal. Metal exchange with complexed cations and the formation of basic cupric carbonate are time-consuming and responsible for about 24% (w/w) of Cu(II) removal. Graphical abstract ᅟ
Показать больше [+] Меньше [-]Evaluation of vulnerable PM2.5-exposure individuals: a repeated-measure study in an elderly population Полный текст
2018
Chu, Haiyan | Xin, Junyi | Yuan, Qi | Zhang, Xu | Pan, Wang | Zeng, Xinying | Chen, Yaoyao | Ma, Gaoxiang | Ge, Yuqiu | Du, Mulong | Tong, Na | Li, Xiaobo | Zhang, Zhengdong | Wang, Meilin
Numerous studies have shown that elderly people are susceptible to high-level particles with aerodynamic diameter ≤ 2.5 μm (PM₂.₅) exposure. However, not all elderly people exposed to PM₂.₅ suffer from diseases. In this study, we aim to establish a method to predict the vulnerable PM₂.₅-exposure individuals among elderly population. Fourteen elderly people were recruited from May 8 to July 4, 2016, in Nanjing, China. Ten physiological indicators were repeatedly measured for 15 times. Liner mixed-effects model, principal component analysis (PCA), and PM₂.₅ lag score were used to estimate the effects of PM₂.₅ on blood pressure, pulse, and lung function. As a result, each quartile increase of ambient PM₂.₅ was significantly associated with increased pulse (P < 0.05 for lag0, 1, 4, 0–1, 0–2, 0–3, and 0–5 days), decreased blood pressure (P < 0.05 for lag4 and 0–3 days), and decreased lung function (P < 0.05 for lag0, 1, 0–1, and 0–2 days) among the 14 elderly people. In terms of pulse or lung function, three elderly people were considered as vulnerable PM₂.₅-exposure individuals. No vulnerable individual was found for blood pressure. Blood pressure, pulse, and lung function could be affected by high-level PM₂.₅ exposure in elderly people. This method for screening three elderly people may provide a new insight on identifying the vulnerable PM₂.₅-exposure individuals.
Показать больше [+] Меньше [-]Assessment of progeny concentrations of 222Rn/220Rn and their related doses using deposition-based direct progeny sensors Полный текст
2018
Śarmā, Sumīta | Kumar, Ajay | Mehra, Rohit | Manpreet Kaur, | Mishra, Rosaline
Indoor radon and thoron concentrations in the domestic environment result in natural radiation exposure to the public due to the inhalation of their short-lived decay products. Keeping this in view, the annual effective dose and other radiation risks due to radon/thoron progenies have been calculated. In this study, newly developed time deposition-based progeny sensors (DTPS/DRPS) were used for long-term passive determination of progeny concentrations in the environment of Jammu and Kashmir, Himalayas, India. The total equilibrium equivalent radon (EECRA ₊ U) and thoron (EECTA ₊ U) concentrations (“A” and “U” referring to attached and unattached fractions) were found to vary from 5 to 38 Bq m⁻³ with an average value of 18 Bq m⁻³ and from 0.48 to 5.49 Bq m⁻³ with an average value of 1.69 Bq m⁻³, respectively. The aerosol concentration, equilibrium factors, and unattached fractions for radon and thoron progeny have been estimated in normal living conditions and their dependence on each others have also been studied. The annual equilibrium factor for radon and thoron progeny has been determined from the calculated data. The estimated annual effective dose due to radon progeny (0.34 to 2.42 mSv y⁻¹) and thoron progeny (0.13 to 1.54 mSv y⁻¹) is found to be below the world’s recommended level. Based on measurements of mean values of the unattached fraction, dose conversion factors (DCFs) in units of mSv per working level month (WLM) has been calculated and the average calculated values of DCFs are 24, 10, and 13 mSv WLM⁻¹. The variability of equilibrium factor and radon/thoron progeny with different seasons, ventilation conditions, and types of houses were also analyzed.
Показать больше [+] Меньше [-]Acute effects of air pollution on spontaneous abortion, premature delivery, and stillbirth in Ahvaz, Iran: a time-series study Полный текст
2018
Dastoorpoor, Maryam | Idani, Esmaeil | Goudarzi, Gholamreza | Khanjani, Narges
Living in areas with high air pollution may have adverse effects on human health. There are few studies about the association between breathing polluted air and adverse pregnancy outcomes in the Middle East. The aim of this study was to determine the relationship between air pollution and spontaneous abortion, premature birth, and stillbirth in Ahvaz. A time-series study was conducted. Data about spontaneous abortion, premature deliveries, and stillbirth was collected from Ahvaz Imam Khomeini Hospital. Air pollution data including NO, CO, NO₂, PM₁₀, SO₂, O₃, and climate data were, respectively, collected from the Environmental Protection Agency and the Khuzestan Province Meteorology Office from March 2008 until March 2015. The relationship between air pollutants with the number of abortions, premature births, and stillbirths was found using a quasi-Poisson distributed lag model, adjusted by trend, seasonality, temperature, relative humidity, weekdays, and holidays. The average daily dust in Ahvaz on 7.2% days of the year was higher than 500 μg/m³ (very dangerous). Findings from this study indicate a significant association between each 10-unit increase in SO₂ and spontaneous abortion in lag 0 and 9 days. There was a significant relation between each 10-unit increase in NO₂ and CO, and premature birth in lag 0. Also, we found a significant association between each 10-unit increase in CO and premature delivery in lag 1; PM₁₀ and premature delivery in lags 10, 11, and 12; and NO and premature delivery in lags 3, 4, 10, 11, 12, and 13 (p value < 0.05). Contact with polluted air during pregnancy may increase adverse pregnancy outcomes and stillbirth. Pregnant women should avoid polluted air.
Показать больше [+] Меньше [-]Prevalence of occult hepatitis C virus among hemodialysis patients in Tanta university hospitals: a single-center study Полный текст
2018
Abdelmoemen, Ghada | Khodeir, SamyAbdelkader | Abou- Saif, Sabry | Kobtan, Abdelrahman | Abd-Elsalam, Sherief
Occult hepatitis C virus infection (OCI) is a newly defined type of infection by the chronic hepatitis virus (HCV) distinguished by the existence of HCV RNA in liver tissue and/or peripheral blood mononuclear cells (PBMCs) in patients whose plasma are devoid of both positive serology and RNA. Patients on maintenance hemodialysis evince a higher HCV prevalence than the general population due to high nosocomial transmission by the dialysis units. We investigated the prevalence of occult HCV infection in patients attending our university hemodialysis centers for maintenance hemodialysis. Sixty-two CHD patients negative for serum HCV tests were enrolled in the study. PMNCs were tested by real-time PCR for the presence of HCV RNA. For the 62 patients, the average duration since starting dialysis was 32.7 months and the mean (SD) alanine transaminase and aspartate transaminase were 25.74 ± 9.75 and 28.81 ± 11.32 IU/l, respectively. Out of the 62 CHD patients negative for serum anti-HCV and HCV RNA patients, only three (4.84%) were shown to have HCV RNA in their PBMCs implying the diagnosis of OCI; their viral load range was 1.24–4.15 IU/ml. All three OCI-proven patients gave no history of hepatic disease. In this study, we found that patients considered to be free of HCV can have HCV replicating in their PBMCs. This awareness points to the possibility of HCV being transmitted from apparently uninfected persons. A positive HCV RNA detection in PBMCs is dependable in determining OCI among high-risk subjects particularly when a liver biopsy is not an option. HCV transmission can occur through hemodialysis units signaling incorrect application of infection control measures in our Egyptian dialysis units. Additional studies on hemodialysis patients are necessary to realize the true magnitude of OCI among this patient group and to highlight the importance of incorporating HCV viral assays in PBMCs into the diagnostic algorithm.
Показать больше [+] Меньше [-]Revisiting energy intensity convergence: new evidence from OECD countries Полный текст
2018
Bulut, Umit | Durusu-Ciftci, Dilek
In this study, we examine the energy intensity convergence in OECD countries within the context of recent developments in unit root analysis by paying attention to modeling structural shifts. We collect the total primary energy consumption/GDP data of 27 OECD countries during the period 1980–2014. The findings indicate that controlling for shifts plays a crucial role, and different approximations in modeling breaks lead to changes in inferences. In conclusion, we present some policy proposals.
Показать больше [+] Меньше [-]