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Residue behavior and risk assessment of cymoxanil in grape under field conditions and survey of market samples in Guangzhou
2019
Huang, Jianxiang | Ye, Qian | Wan, Kai | Wang, Fuhua
A simple and fast method based on liquid chromatography-tandem mass spectrometry (LC-MS/MS) was developed for cymoxanil residue analysis in grape. Sample preparation based on solid-liquid extraction was optimized without using adsorbent for purification. Recoveries were 79.8–109.5% with relative standard deviations (RSDs) of 2.5–9.4% at fortified levels from 0.001 to 0.50 mg/kg. The limit of detection (LOD) was 0.3 μg/kg. Field trials were conducted to explore the dissipation and terminal residue behavior of cymoxanil in grape. Results showed that the half-lives of cymoxanil were from 0.5 to 0.7 days. Terminal residues were from below the limit of quantification (LOQ) to 0.363 mg/kg. Dietary exposure risk assessment revealed that the risk quotients (RQs) were much less than 1. It was concluded that cymoxanil in grape raised negligible concerns to human health under field conditions. Sixty grape samples from Guangzhou market were found to be free of cymoxanil. The proposed study would provide reference for appropriate use of cymoxanil in grape planting in China.
Mostrar más [+] Menos [-]Effect of carbon source on lipid accumulation and biodiesel production of Yarrowia lipolytica
2019
Chai, Baohua | Wang, Yi | Wang, Wenhuai | Fan, Pan
Yarrowia lipolytica (Y. lipolytica) is an oleaginous yeast that can utilize hydrophobic substrates as carbon source to produce single-cell lipids for biodiesel production. This study attempts to increase the lipid accumulation ability of Y. lipolytica by first gradually elevating pure oil substrate concentration during the cultivation and then adding short-chain carbon compounds, such as glucose and sodium acetate, to a culture substance according to the optimal oil concentration. Results showed that Y. lipolytica cultured under 40.0 g L⁻¹ oil concentration showed higher lipids (2.97 g L⁻¹) and lipid content (37.35%, DW) compared with that cultured under 20.0 g L⁻¹, where the corresponding values were 1.91 g L⁻¹ and 24.46%. By contrast, the lipid content of Y. lipolytica increased from 37.35 to 41.50% when the substrate was changed from 40.0 g L⁻¹ pure oil to 5% sodium acetate combined with 95% oil under the same total carbon concentration. However, lipid accumulation did not increase even though 15% sodium acetate or 5% glucose, or 15% glucose was added to the combined substrate. Moreover, the lipid biomodification of Y. lipolytica was evident when it was cultured under the oil concentration of 20.0 g L⁻¹. Therefore, the lipid accumulation of Y. lipolytica can be elevated through the gradient increase of oil concentration and by adding a suitable amount of easily degradable carbon source. Furthermore, the lipid biomodification of Y. lipolytica improves biodiesel quality.
Mostrar más [+] Menos [-]Novel waste-derived biochar from biomass gasification effluent: preparation, characterization, cost estimation, and application in polycyclic aromatic hydrocarbon biodegradation and lipid accumulation by Rhodococcus opacus
2019
Goswami, Lalit | Manikandan, Natarajan Arul | Taube, Jebathomas Christon Ringle | Pakshirajan, Kannan | Pugazhenthi, Gopal
This study evaluated an enhancement of simultaneous polycyclic aromatic hydrocarbon (PAH) biodegradation and lipid accumulation by Rhodococcus opacus using biochar derived cheaply from biomass gasification effluent. The chemical, physical, morphological, thermal, and magnetic properties of the cheaply derived biochar were initially characterized employing different techniques, which indicated that the material is easy to separate, recover, and reuse for further application. Batch experiments were carried out to study biochar-aided PAH biodegradation by R. opacus clearly demonstrating its positive effect on PAH biodegradation and lipid accumulation by the bacterium utilizing the synthetic media containing 2-, 3- or 4-ring PAH compounds, at an initial concentration in the range 50–200 mg L⁻¹, along with 10% (w/v) inoculum. An enhancement in PAH biodegradation from 79.6 to 92.3%, 76.1 to 90.5%, 74.1 to 88.2%, and 71.6 to 82.3% for naphthalene, anthracene, phenanthrene, and fluoranthene, respectively, were attained with a corresponding lipid accumulation of 68.1%, 74.2%, 72.4%, and 63% (w/w) of cell dry weight (CDW). From contact angle measurements carried out in the study, enhancement in PAH biodegradation and lipid accumulation due to the biochar was attributed to an improved bioavailability of PAH to the degrading bacterium.
Mostrar más [+] Menos [-]Co-exposures to toxic metals cadmium, lead, and mercury and their impact on unhealthy kidney function
2019
Jain, Ram B.
Cross-sectional data (N = 25427) from the National Health and Nutrition Examination Survey for 2003–2014 for US adults were used to estimate the impact of co-exposure to high levels of cadmium, lead, and mercury on the unhealthy kidney function. If observed concentrations of cadmium, lead, and total mercury were above the 75th percentile of their respective distributions, the exposure to the corresponding metal was considered to be high. Logistic regression models were fitted to estimate the probabilities of an unhealthy kidney function. Two alternate definitions of unhealthy kidney function were used. First, if estimated, glomerular filtration rate (eGFR) was < 60 mL/min/1.73 m² (KₑGFR) and second, if the observed albumin creatinine ratio (ACR) was ≥ 30 mg/g creatinine (KACR). As compared with low exposures, adjusted odds ratios (AOR) for unhealthy kidney function when exposed to high levels of lead and cadmium were observed to be 1.567 (1.346–1.823) and 1.663 (1.376–2.010) respectively for KₑGFR. When exposed to high levels of both cadmium and lead, AORs for unhealthy kidney functions KₑGFR and KARC were found to be 2.369 (1.868–3.004) and 1.522 (1.216–1.905) respectively. When exposed to high levels of cadmium, lead, and mercury, AORs for unhealthy kidney functions KₑGFR and KARC were found to be 2.248 (1.428–3.538) and 1.502 (1.024–2.204) respectively. High exposure to lead along with any level of exposure to cadmium and total mercury was found to adversely affect the health of kidney function. High exposure to mercury does not affect unhealthy kidney function.
Mostrar más [+] Menos [-]Amelioration of hepatic function, oxidative stress, and histopathologic damages by Cassia fistula L. fraction in thioacetamide-induced liver toxicity
2019
Kaur, Sandeep | Sharma, Dipakshi | Singh, Amrit Pal | Kaur, Satwinderjeet
Cassia fistula L. (Caesalpinioideae) is a highly admirable medicinal plant and is traditionally recommended for the treatment of rheumatism, liver disorders, jaundice, and other inflammatory diseases. This study was designed to investigate the hepatoprotective properties of ethyl acetate fraction from C. fistula leaves in an animal model. Treatment with thioacetamide significantly elevated the level of serum glutamic-oxaloacetic transaminase (1.75-fold), alkaline phosphatase (4.07-fold), and total bilirubin (2.29-fold) as compared to the control. It was found that pretreatment of fraction followed by consecutive 2 days thioacetamide reduced the conversion of thioacetamide carcinogen to its reactive metabolites by phase I enzymes and increased the level of detoxification phase II along with antioxidative enzymes. The histopathological studies revealed the hepatoprotective nature of the fraction in restoring the normal architecture of thioacetamide-intoxicated damaged liver. The fraction showed downregulation in the expression level of p-PI3K, p-Akt, and p-mTOR pointing towards its chemopreventive potential. The HPLC analysis of the fraction had shown the dominance of three phenolic compounds namely, catechin, epicatechin, and chlorogenic acid. The above studies comprising histopathological, immunohistochemical, and hepatic enzymes are strong indicative of the potential protective ability of ethyl acetate fraction phytoconstituents against thioacetamide-induced toxicity. Graphical abstract
Mostrar más [+] Menos [-]Prevalence of mycotoxins in feed and feed ingredients between 2015 and 2017 in Taiwan
2019
Yang, Ching-Kuo | Cheng, Yeong-Hsiang | Tsai, Wan-Ting | Liao, Rou-Wan | Zhang, Jiasheng | Chien, Wan-Chu | Jhang, Jia-Cin | Yu, Yu-Hsiang
Contamination of feed by mycotoxins is a global epidemic that has a sizeable impact on animal health and causes economic losses. Mycotoxins, including aflatoxins (AFs), zearalenone (ZEN), fumonisins (FUMs), deoxynivalenol (DON), and ochratoxin A (OTA), lead to acute and chronic adverse effects in pigs. Animal feed and feed ingredients are commonly contaminated by one or more mycotoxins worldwide; however, the prevalence of mycotoxin contamination in feed and feed ingredients in Taiwan remains unclear. A total of 820 cornmeal and corn-based swine feed (pregnancy and nursery diets) samples provided by feed and animal producers were analyzed using the enzyme-linked immunosorbent assay method between January 2015 and December 2017 to determine the presence of mycotoxins. The results revealed that the most prevalent mycotoxin in Taiwan was DON, with 91.4% of positive samples between 2015 and 2017, followed by ZEN, AFs, and FUMs, with 70.2%, 58.0%, and 50.4% of positive samples, respectively. A similar prevalence of mycotoxins was observed in cornmeal and corn-based swine feed. Furthermore, 7.7% of the analyzed feed samples contained one mycotoxin, and 91.3% contained multiple mycotoxins. DON was the most prevalent mycotoxin in cornmeal and corn-based swine feed in Taiwan. Moreover, a high incidence of contamination by multiple mycotoxins was observed in swine feed. Awareness of mycotoxin presence in feed and development of mycotoxin detoxification strategies are unmet needs.
Mostrar más [+] Menos [-]Lichen Parmelia sulcata mediated synthesis of gold nanoparticles: an eco-friendly tool against Anopheles stephensi and Aedes aegypti
2019
Gandhi, Arumugam Dhanesh | Murugan, Kadarkarai | Umamahesh, Katike | Babujanarthanam, Ranganathan | Kavitha, Purushothaman | Selvi, Adikesavan
The gold nanoparticles (AuNPs) were synthesized using the lichen Parmelia sulcata extract (PSE) and characterized. The peaks of ultraviolet spectrophotometer and Fourier transmission infrared confirmed the formation of nanoparticles and the bioactive compounds of the lichen being responsible for reducing and capping of the particles. The face-centered cubic particles were determined by XRD peaks at 111, 200, 220, and 311. The elemental composition and spherical shape of AuNPs were confirmed by energy-dispersive spectroscopy and transmission electron microscopy. The average particle size is 54 nm, and the zeta potential − 18 was ascertained by dynamic light scattering. The potential effect of synthesized nanoparticles and lichen extracts was evaluated for antioxidant bioassays like DPPH and H₂O₂ and tested for mosquitocidal activity against Anopheles stephensi. Results showed that the lichen extract and AuNPs have the capability to scavenge the free radicals with the IC₅₀ values of DPPH being 1020 and 815 μg/ml and the IC₅₀ values of H₂O₂ being 694 and 510 μg/ml, respectively. The mosquitocidal experimental results in this study showed the inhibition of A. stephensi and A. aegypti against the larvae (I–IV instar), pupae, adult, and egg hatching. On comparison, A. stephensi showed effective inhibition than A. aegypti even at low concentration. Based on the obtained results, gold nanoparticles synthesized using PSE showed an excellent mosquitocidal effect against Anopheles stephensi.
Mostrar más [+] Menos [-]The distributions, contamination status, and health risk assessments of mercury and arsenic in the soils from the Yellow River Delta of China
2019
Ge, Meng | Liu, Guijian | Liu, Houqi | Yuan, Zijiao | Liu, Yuan
The surface soils were collected from four areas in the Yellow River Delta (YRD), including three functional areas in the natural reserve of the YRD (the core area, buffer area, and experimental area) and a neighboring area of the natural reserve. The total concentrations, speciations, contamination status, and health risk assessments of the mercury (Hg) and arsenic (As) in surface soils of the YRD were investigated. The average Hg concentration was about three times that of the background value, while As was just slightly higher than the background. Hg levels in the sites of experimental area were significantly higher than those in the core area and buffer area, which was consistent with the human activity intensities of the three functional areas. However, no significant differences of As levels were observed across different areas. According to the sequential extraction experiments, only less than 5% of Hg and As were associated with the exchangeable fraction, while over 80% of them were found in the residual fraction, indicating low mobility and bioavailability of both Hg and As. The soil contamination status assessments suggested a “good state,” and the health risk assessments indicated a “low risk” of Hg and As in the soils of YRD.
Mostrar más [+] Menos [-]Is the World Health Organization predicted exposure assessment model for space spraying of insecticides applicable to agricultural farmers?
2019
Phùng, Dũng | Miller, Greg | Connell, Des | Chu, Cordia
Agricultural farmers in developing countries are at high risk of pesticide exposure and adverse effects because of unsafe practices and inappropriate legislation. Biological monitoring is considered a useful tool for pesticide exposure assessment; however, its use is limited in developing countries due to a lack of techniques and resources such as laboratory analysis, trained staff and budgets. This study examines whether the World Health Organization predicted exposure assessment model (WHO-PEAM) is a suitable alternative tool for assessing insecticide exposure among agricultural farmers. WHO-PEAM was used to predict daily doses (PDD) of chlorpyrifos for a group of Vietnamese rice farmers using a set of exposure parameters obtained from a questionnaire survey of participant famers during a field study. These results were compared to absorbed daily doses (ADD) of chlorpyrifos for the farmers measured using a biological monitoring program, in which 24-h urine samples were collected and analysed for the chlorpyrifos metabolite, 3,5,6-trichloro-2-pyridinol (TCP) using LC/MS. Validation of the model results was tested using the Wilcoxon signed-rank test (WSR) and two-way mixed-model intraclass correlation coefficient (ICC). The mean of total ADD was 20 μg/kg/day while that of total PDD was 22 μg/kg/day. The WSR test revealed no statistically significant difference in the average values of ADDT and PDDT. ICC indicated substantial agreement for both single and average measures between ADDT and PDDT (ICC, 0.62 and 0.77, respectively). The results demonstrate that a refined WHO-PEAM model can be readily used as a field method, without biological monitoring, to evaluate chlorpyrifos exposure among agricultural farmers in Vietnam and similar developing countries.
Mostrar más [+] Menos [-]Do renewable energy consumption and service industry development contribute to CO2 emissions reduction in BRICS countries?
2019
Zhang, Yue-Jun | Wang, Wei
In recent years, BRICS countries have attached great importance to renewable energy development and actively promoted the shift of economic structure towards service industry, in order to achieve the decoupling of economic development from carbon emissions. However, relevant studies mostly neglect the cross-sectional dependence and heterogeneity issues, which may cause biased results. Therefore, this paper selects the panel data of BRICS countries during 1996–2017 and employs the common correlated effects mean group (CCEMG) method, which are based on the cross-sectional dependence and heterogeneity assumptions, to explore the influence of renewable energy consumption and service industry development on CO₂ emissions in BRICS countries. Besides, we also use the random effects model and pooled estimated generalized least squares model, as well as fully modified OLS model for comparison. The results indicate that enhancing the proportion of renewable energy consumption in the total energy consumption is an effective measure to reduce CO₂ emissions in BRICS countries. Moreover, the steadily rising contribution of service industry to economic growth in BRICS countries during the sample period does not necessarily contribute to reduce CO₂ emissions.
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