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Isolation and purification of antialgal compounds from the red alga Gracilaria lemaneiformis for activity against common harmful red tide microalgae Полный текст
2017
Sun, Ying-ying | Meng, Kun | Su, Zhen-xia | Guo, Gan-lin | Pu, Yin-fang | Wang, Chang-hai
Seven antialgal compounds (1–7) were successfully isolated from the red alga Gracilaria lemaneiformis through a combination of silica gel column chromatography and repeated preparative thin-layer chromatography. On the basis of the spectral data, the compounds were identified as gossonorol (1), 7,10-epoxy-ar-bisabol-11-ol (2), glycerol monopalmitate (3), stigmasterol (4), 15-hydroxymethyl-2, 6, 10, 18, 22, 26, 30-heptamethyl-14-methylene-17-hentriacontene (5), 4-hydroxyphenethyl alcohol (6), and margaric acid (7). These seven compounds were isolated from G. lemaneiformis for the first time, while the compounds 4, 6, and 7 were isolated from marine macroalgae for the first time. Furthermore, a quantitative relationship between the inhibition of algal growth and the concentration of each antialgal compound was determined and important parameters for future practical HAB control, e.g., EC₅₀₋₉₆ₕ, were also obtained. The results indicated that isolated compounds 1–7 possess selective antialgal activity against the growth of several red tide microalgae (including Amphidinium carterae, Heterosigma akashiwo, Karenia mikimitoi, Phaeocystis globsa, Prorocentrum donghaiense, and Skeletonema costatum). Their antialgal activity against test red tide microalgae has not been previously reported. Furthermore, the EC₅₀₋₉₆ₕ of one or more of the compounds towards the tested red microalgae was not only significantly less than 10 μg/mL but also was smaller than that of the characteristic antialgal agent potassium dichromate. The study demonstrates that compounds 1–7 possess significant application potential as antialgal agents against several harmful red tide microalgae.
Показать больше [+] Меньше [-]Rice agriculture impacts catchment hydrographic patterns and nitrogen export characteristics in subtropical central China: a paired-catchment study Полный текст
2017
Wang, Yi | Liu, Xinliang | Wang, Hua | Li, Yong | Li, Yuyuan | Liu, Feng | Xiao, Runlin | Shen, Jianlin | Wu, Jinshui
Increased nitrogen (N) concentrations in water bodies have highlighted issues regarding nutrient pollution in agricultural catchments. In this study, the ammonium-N (NH₄ ⁺-N), nitrate-N (NO₃ ⁻-N), and total N (TN) concentrations were observed in the stream water and groundwater of two contrasting catchments (named Tuojia and Jianshan) in subtropical central China from 2010 to 2014, to determine the rice agriculture impacts on the hydrographic patterns, and N export characteristics of the catchments. The results suggested that greater amounts of stream flow (523.0 vs. 434.7 mm year⁻¹) and base flow (237.6 vs. 142.8 mm year⁻¹) were produced in Tuojia than in Jianshan, and a greater base flow contribution to stream flow and higher frequencies of high-base flow days were observed during the fallow season than during the rice-growing season, indicating that intensive rice agriculture strongly influences the catchment hydrographic pattern. Rice agriculture resulted in moderate N pollution in the stream water and groundwater, particularly in Tuojia. Primarily, rice agriculture increased the NH₄ ⁺-N concentration in the stream water; however, it increased the NO₃ ⁻-N concentrations in the groundwater, suggesting that the different N species in the paddy fields migrated out of the catchments through distinct hydrological pathways. The average TN loading via stream flow and base flow was greater in Tuojia than in Jianshan (1.72 and 0.58 vs. 0.72 and 0.15 kg N ha⁻¹ month⁻¹, respectively). Greater TN loading via stream flow was observed during the fallow season in Tuojia and during the rice-growing season in Jianshan, and these different results were most likely a result of the higher base flow contribution to TN loading (33.5 vs. 21.3%) and greater base flow enrichment ratio (1.062 vs. 0.876) in Tuojia than in Jianshan. Therefore, the impact of rice agriculture on catchment eco-hydrological processes should be considered when performing water quality protection and treatment in subtropical central China.
Показать больше [+] Меньше [-]Air pollution and respiratory health among diabetic and non-diabetic subjects in Pune, India—results from the Wellcome Trust Genetic Study Полный текст
2017
Khafaie, Morteza Abdullatif | Salvi, Sundeep Santosh | Yajnik, Chittaranjan Sakerlal | Ojha, Ajay | Khafaie, Behzad | Gore, Sharad Damodar
Diabetics may be more vulnerable to the harmful effects of ambient air pollutants than healthy individuals. But, the risk factors that lead to susceptibility to air pollution in diabetics have not yet been identified. We examined the effect of exposure to ambient PM₁₀ on chronic symptoms and the pulmonary function tests (PFT) in diabetic and non-diabetic subjects. Also, to investigate possible determinants of susceptibility, we recruited 400 type 2 diabetic and 465 healthy subjects who were investigated for chronic respiratory symptoms (CRSs) and then underwent measurement of forced vital capacity (FVC) and forced expiratory volume 1 (FEV1) according to standard protocol. Percent predicted FEV1 and FVC (FEV1% and FVC%, respectively) for each subject were calculated. Particulate matter (PM₁₀) concentrations at residence place of subjects were estimated using AERMOD dispersion model. The association between PM₁₀ and CRSs was explored using logistic regression. We also used linear regression models controlling for potential confounders to study the association between chronic exposure to PM₁₀ and FEV1% and FVC%. Prevalence of current wheezing, allergy symptom, chest tightness, FEV1/FVC <70%, and physician-diagnosed asthma and COPD was significantly higher among diabetic subjects than non-diabetics. There was no significant difference between percent predicted value of PFT among diabetic and non-diabetic subjects (P < 0.05). We estimated that 1 SD increase in PM₁₀ concentration was associated with a greater risk of having dyspnea by 1.50-fold (95% CI, 1.12–2.01). Higher exposure to PM₁₀ concentration was also significantly associated with lower FVC%. The size of effect for 1 SD μg/m³ (=98.38) increase in PM₁₀ concentration was 3.71% (95% CI, 0.48–4.99) decrease in FVC%. In addition, we indicated that strength of these associations was higher in overweight, smoker, and aged persons. We demonstrated a possible contribution of air pollution to reduced lung function independent of diabetes status. This study suggests that decline in exposure may significantly reduce disease manifestation as dyspnea and impaired lung function. We conduct that higher BMI, smoking, and older age were associated with higher levels of air pollution effects.
Показать больше [+] Меньше [-]Microwave-assisted enhancement of milkweed (Calotropis procera L.) leaves as an eco-friendly source of natural colorants for textile Полный текст
2017
Hussaan, Muhammad | Iqbal, Naeem | Adeel, Shahid | Azeem, Muhammad | Tariq Javed, M. | ʻAlī, Raz̤ā
Application of natural colorants to textile fabrics has gained worldwide public acceptance due to the hazardous nature of synthetic dyes. Present study investigated the microwave’s mediated extraction of natural colorants from leaves of milkweed (Calotropis procera L.) as well as their application to cotton fabrics assisted with biochemical mordants. Dye extraction from C. procera leaves was carried out in various mediums (alkali and aqueous), and the extracted dye as well as cotton fabrics was irradiated with microwaves for 2, 4, 6, 8, or 10 min. Effect of various temperature regimes and sodium chloride (NaCl) concentrations was also evaluated on the color strength of dyed cotton fabrics. The results revealed that extraction of natural colorants was enhanced when microwave radiations were applied for 4 min by using alkali as an extraction medium as compared to aqueous one. Optimum dyeing of cotton fabrics was achieved by using NaCl at a temperature of 55 °C. Among the chemical mordants, iron was effective for better color strength when used as pre- and post-mordant. Among the studied bio-mordants, extract of Acacia nilotica bark significantly improved the color strength and fastness properties as pre-mordant and Curcuma longa tuber as post-mordant. It was concluded that extract of C. procera leaves was a potential source of natural colorants and a high level of dye was obtained upon irradiation of alkali-solubilized extract for 4 min. Application of NaCl at concentration of 3 g/100 mL and temperature treatment of 55 °C significantly improved the color strength of dyed cotton fabrics.
Показать больше [+] Меньше [-]Does the groundwater nitrate pollution in China pose a risk to human health? A critical review of published data Полный текст
2017
Zhai, Yuanzheng | Lei, Yan | Wu, Jin | Teng, Yanguo | Wang, Jinsheng | Zhao, Xiaobing | Pan, Xiaodong
Nitrate pollution has pervaded many parts of the world, especially in developing countries such as China. Based on the available groundwater nitrate data sets in China (2000–2015), the groundwater pollution levels at the provincial scale are evaluated which contains 33 provinces (units) except for Macau because of lacking data. Then, the potential risks posed to human health in national scale are quantified. In order to make the results more precise and systematical, both drinking and dermal contact exposure pathways are considered, and the influenced crowd are more finely divided into four groups to study the impacts of age and gender on the outcome, which include infants (0–6 months), children (7 months–17 years old), adult males (18 years old–), and adult females (18 years old–). Results indicate that there are seven units whose groundwater nitrate concentrations exceed the standard value with Shaanxi being a seriously poor condition. Facing the same level of nitrate, the health risk level changes in the order of infants > children > adult males > adult females. That is to say, minors and males are more vulnerable compared with adults and females, respectively. There is no adverse effect on adult females of the whole country, while gender really impacts on the health risk assessment result. Adult males, children, and infants face various degrees of health risk respectively in Shaanxi and Shandong, which are needed to pay more attention to.
Показать больше [+] Меньше [-]Exposure assessment of a cyclist to particles and chemical elements Полный текст
2017
Ramos, C. A. | Silva, J. R. | Faria, T. | Wolterbeek, T. H. | Almeida, S. M.
Cycle paths can be used as a route for active transportation or simply to cycle for physical activity and leisure. However, exposure to air pollutants can be boosted while cycling, in urban environments, due to the proximity to vehicular emissions and elevated breathing rates. The objective of this work was to assess the exposure of a cyclist to particles and to chemical elements by combining real-time aerosol mass concentration reading equipment and biomonitoring techniques. PM₁₀ and PM₂.₅ were measured on three cycle paths located in Lisbon, during weekdays and weekends and during rush hours and off-peak hours resulting in a total of 60 campaigns. Lichens were exposed along cycle paths for 3 months, and their element contents were measured by instrumental neutron activation analysis using the k ₀ methodology (k ₀-INAA). Using a bicycle commute route of lower traffic intensity and avoiding rush hours or other times with elevated vehicular congestion facilitate a reduction in exposure to pollutants. The implementation of cycle paths in cities is important to stimulate physical activity and active transportation; however, it is essential to consider ambient air and pollutant sources to create safer infrastructures.
Показать больше [+] Меньше [-]Low-level arsenic causes chronic inflammation and suppresses expression of phagocytic receptors Полный текст
2017
Prasad, Priyanka | Sinha, Dona
The impact of chronic low-level groundwater arsenic (As) exposure [in the range above the WHO-recommended limit of 10 μg/L but ≤50 μg/L (permissible limit of As for many Asian countries)] was investigated for cross talk of inflammatory changes and expression of phagocytic receptors of exposed rural women (N, 45) from districts of 24 Parganas (south) and in matched control groups (N, 43) [As ≤10 μg/L] from the same district. Systemic inflammation was evident from the upregulated levels of pro-inflammatory mediators like tumor necrosis factor-α (TNF-α); interleukins (ILs) like IL-6, IL-8, and IL-12; and C-reactive protein (CRP) in the sera and upregulated expression of protein kinase B phosphorylated at ser473 (pAKTser473)/nuclear factor-κB (NF-κB)/TNF-α axis in the leukocytes of exposed women with respect to control. We found that low-dose As exposure apart from inflicting inflammation altered the expression of phagocytic receptors—Fcγ receptors (FcγRs) and complement receptors (CRs). The leukocytes of the low-As-exposed women exhibited suppression of CD64, CD35, and CD11b and increased expression of CD16 with respect to control. Groundwater As showed a negative correlation with CD64 expression on monocytes [Pearson’s r, −0.8205; 95% confidence interval (CI), −0.8789 to −0.7379] and granulocytes [r, −0.7635; 95% CI, −0.8388 to −0.6595] and a positive correlation with CD16 on granulocytes [r, 0.8363; 95% CI, 0.7599 to 0.8899]. A negative correlation of groundwater As was also observed with expression of CD35 on granulocytes [r, −0.8780; 95% CI, −0.9185 to −0.8192] and monocytes [r, −0.7778; 95% CI, −0.8490 to −0.6790] and CD11b on monocytes [r, −0.6035; 95% CI, −0.7218 to −0.4511]. Therefore, it may be indicated that chronic low-level As exposure (11–50 μg/L) not only evoked chronic inflammatory changes but also suppressed the expression of FcγRs and CRs in the exposed women. This, in turn, may lead to susceptibility towards pathogenic infections or in long run may even contribute towards chronic inflammatory diseases including cancer.
Показать больше [+] Меньше [-]Stability of BiFeO3 nanoparticles via microwave-assisted hydrothermal synthesis in Fenton-like process Полный текст
2017
Li, Shuo | Zhang, Guangshan | Zheng, Heshan | Zheng, Yongjie | Wang, Peng
Stable catalysts require high catalytic efficiency and repeated consecutive use, low mass loss, and metal leaching. This study investigated BiFeO₃ (BFO) composite with high stability and reusability using a one step microwave-assisted hydrothermal method (MAHS) to decompose bisphenol A (BPA) used as the target contaminant. After six consecutive reaction cycles in microwave-enhanced Fenton-like process (MW-Fenton-like), the removal rate of BPA decreased from 94 to 87.4% with low metal leaching ratio and mass loss. The morphology, crystal, reaction kinetics, and hydroxyl radical (·OH) were used to demonstrate the high stability of BFO-MAHS. The results indicated that the benign stability and reusability of BFO-MAHS probably occurred because (1) the thermal-effect of MW improved heating rate, which led to the rapid formation stable cube structure and (2) MW mechanical vibrations existed in the preparation process, which further enhanced the cube structure. Therefore, MAHS could be used as a green and environmental friendly method to apply in catalysts synthesis, which could immensely shorten preparation time and enhance the catalytic performance with no waste production.
Показать больше [+] Меньше [-]Effect of calcium bentonite on Zn and Cu mobility and their accumulation in vegetable growth in soil amended with compost during consecutive planting Полный текст
2017
Wang, Quan | Awasthi, Mukesh Kumar | Ren, Xiuna | Zhao, Junchao | Li, Ronghua | Shen, Feng | Zhang, Zengqiang
In this study, greenhouse pot experiment was carried out to investigate the Cu and Zn mobility and their accumulations in pakchoi (Brassica chinensis L.) and Chinese cabbage (Brassica rapachinensis L.) growth in Ca-bentonite-pig manure co-compost (CBC)–soil system during three consecutive planting. Five composts (0, 2.5, 5, 7.5, and 10% Ca-bentonite-pig manure co-composts) amended soil with 5% (w/w) application rate and compared to control without any additive. The results showed that the addition of CBC increased the biomass and chlorophyll content of pakchoi, and the maximum overall yield was found in 7.5% CBC treatment (12.89 ± 0.25 g), while when compared with the 0% CBC (15.89 ± 0.52 g) treatment, the Ca-bentonite amendment slightly decreased the Chinese cabbage yield (14.65 ± 0.11–15.41 ± 1.97 g). Additionally, compared to the 0% CBC treatment (11.81 ± 0.57–25.75 ± 0.89 mg/kg), the Ca-bentonite amendments showed a positive effect on restraining the diethylene triamine penta-acetic acid Zn mobilization (4.43 ± 0.41–12.48 ± 2.54 mg/kg) in pakchoi and Chinese cabbage; beside this, no obvious effect was observed on DTPA-Cu. Furthermore, there were great potential impacts for plant-available Zn in Ca-bentonite amended treatments during the consecutive planting, which decreased the content of Zn in plants. DTPA extraction results showed significantly higher Cu and Zn contents in compost–soil mixture, but its availability for grown plant was not confirmed during the consecutive planting, because of the consecutive decrease heavy metals contents in crops. Overall, the Ca-bentonite could be a useful additive for restricting the heavy metal mobility and increase the pakchoi yield.
Показать больше [+] Меньше [-]One-pot synthesis of lightly doped Zn1−x Cu x O and Au–Zn1−x Cu x O with solar light photocatalytic activity in liquid phase Полный текст
2017
Fkiri, Anis | Santacruz, Marisa Rico | Mezni, Amine | Smiri, Leila-Samia | Keller, Valérie | Keller, Nicolas
We report on the facile and low-temperature one-pot chemical synthesis of lightly doped Zn₁₋ₓ Cu ₓ O and hybrid Au–Zn₁₋ₓ Cu ₓ O photocatalysts with low Cu molar content (0 < x < 0.7%) using 1,3-propanediol polyol simultaneously as solvent, reducing and a stabilizing agent, without any final thermal treatment. The photocatalysts have been characterized by X-ray diffraction, N₂ adsorption study, UV–vis diffuse reflectance spectroscopy, inductively coupled plasma optical emission spectroscopy, and transmission electron microscopy. The lightly doped hybrid Au–Zn₁₋ₓ Cu ₓ O photocatalysts consisted in faceted quasi-spherical large-size Au nanoparticle cores surrounded by closely packed small-size Zn₁₋ₓ Cu ₓ O nanoparticles. Taking the photocatalytic degradation of Diuron under solar light as liquid-phase test reaction, the lightly doped Au–Zn₁₋ₓ Cu ₓ O hybrid photocatalysts with optimized x = 0.09% Cu content showed strongly enhanced photocatalytic activity when compared to the bare ZnO counterpart. The observed 16-fold higher degradation rate constant resulted jointly from the light doping of ZnO with Cu to form Zn₁₋ₓ Cu ₓ O photocatalyst and further from the addition of gold nanoparticles allowing interfacial oxide-to-metal electron transfer within the hybrid Au–Zn₁₋ₓ Cu ₓ O photocatalyst.
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