خيارات البحث
النتائج 2911 - 2920 من 4,308
Exposure to bisphenol A is directly associated with inflammation in healthy Korean adults النص الكامل
2017
Choi, Yong Jun | Ha, Kyoung Hwa | Kim, Dae Jung
It was recently discovered that bisphenol A (BPA) and phthalates are cardiovascular disruptors. Inflammation is central to the initiation and progression of cardiovascular disease (CVD). This study evaluated whether BPA and different phthalate metabolites are associated with the inflammation marker high-sensitivity C-reactive protein (hs-CRP) in healthy Korean adults. This research is part of an ongoing, population-based study of Korean adults (30–64 years of age) conducted at the Cardiovascular and Metabolic Diseases Etiology Research Center (CMERC). The study enrolled 200 healthy volunteers (96 men, 104 women). Plasma hs-CRP was measured as an inflammation marker. BPA and five phthalate metabolites in urine were analyzed by using liquid chromatography/tandem mass spectrometry. BPA and monobenzyl phthalate (MBzP) differed significantly between the low-hs-CRP (<2 mg/L) and high-hs-CRP (≥2 mg/L) groups. BPA and MBzP were related to hs-CRP in an inverted L-shaped manner. High BPA levels (≥75th percentile) had significant odd ratios (ORs) for high hs-CRP even after adjusting for confounding factors related to obesity and insulin resistance, such as visceral fat volume, body mass index (BMI), adiponectin, high-density lipoprotein (HDL) cholesterol, hemoglobin A1c (HbA1c), and homeostasis model assessment of insulin resistance (HOMA-IR) (OR = 2.85; 95 % CI, 1.16–6.97). However, there was no significant association for MBzP ≥75th percentile. BPA was significantly related to high hs-CRP, even after adjusting for factors related to obesity and insulin resistance. Therefore, BPA could have a direct relationship with systemic inflammation regardless of obesity or insulin resistance.
اظهر المزيد [+] اقل [-]Biohydrogen production from sugarcane bagasse hydrolysate: effects of pH, S/X, Fe2+, and magnetite nanoparticles النص الكامل
2017
Reddy, Karen | Nasr, Mahmoud | Kumari, Sheena | Kumar, Santhosh | Gupta, Sanjay Kumar | Enitan, Abimbola Motunrayo | Bux, F. (Faizel)
Batch dark fermentation experiments were conducted to investigate the effects of initial pH, substrate-to-biomass (S/X) ratio, and concentrations of Fe²⁺ and magnetite nanoparticles on biohydrogen production from sugarcane bagasse (SCB) hydrolysate. By applying the response surface methodology, the optimum condition of steam-acid hydrolysis was 0.64% (v/v) H₂SO₄ for 55.7 min, which obtained a sugar yield of 274 mg g⁻¹. The maximum hydrogen yield (HY) of 0.874 mol (mol glucose⁻¹) was detected at the optimum pH of 5.0 and S/X ratio of 0.5 g chemical oxygen demand (COD, g VSS⁻¹). The addition of Fe²⁺ 200 mg L⁻¹ and magnetite nanoparticles 200 mg L⁻¹ to the inoculum enhanced the HY by 62.1% and 69.6%, respectively. The kinetics of hydrogen production was estimated by fitting the experimental data to the modified Gompertz model. The inhibitory effects of adding Fe²⁺ and magnetite nanoparticles to the fermentative hydrogen production were examined by applying Andrew’s inhibition model. COD mass balance and full stoichiometric reactions, including soluble metabolic products, cell synthesis, and H₂ production, indicated the reliability of the experimental results. A qPCR-based analysis was conducted to assess the microbial community structure using Enterobacteriaceae, Clostridium spp., and hydrogenase-specific gene activity. Results from the microbial analysis revealed the dominance of hydrogen producers in the inoculum immobilized on magnetite nanoparticles, followed by the inoculum supplemented with Fe²⁺ concentration. Graphical abstract ᅟ
اظهر المزيد [+] اقل [-]Light-emitting diodes: whether an efficient source of light for indoor plants? النص الكامل
2017
Rehman, Muzammal | Ullah, Sana | Bao, Yaning | Wang, Bo | Peng, Dingxiang | Liu, Lijun
Availability of sufficient light for growth optimization of plants in greenhouse environment during winter is a major challenge, as light during winter is significantly lower than that in the summer. The most commonly used artificial light sources (e.g., metal halide lamps, high pressure sodium lamps, and high fluorescent lamps) are of low quality and inefficient. Therefore, better options should be developed for sustaining agricultural food production during low levels of solar radiation. In recent advances, light-emitting diodes (LEDs) have remarkable potential as supplemental source of light for promoting plant growth. LEDs are novel and versatile source of light with cool emitting surface, wavelength specificity, and low electric power requirement. In the present study, we provided a contemporary synthesis of existing evidence along with our hypothetical concepts to clarify how LED approach could be an efficient and cost-effective source of light for plant growth and development especially in closed production system. In comparative analysis of common artificial vs. LED lighting, we revealed that spectral quality of LEDs can have vivid effects on plant morphogenesis and anatomy. We also discussed the influence of different colors of LEDs on growth performance of plants and provided the cost benefit analysis of using LEDs compared with other traditional sources. Overall, we hope that this article will be of great worth in future due to its practical implications as well as research directions.
اظهر المزيد [+] اقل [-]Citric acid enhanced the antioxidant defense system and chromium uptake by Lemna minor L. grown in hydroponics under Cr stress النص الكامل
2017
Sallah-Ud-Din, Rasham | Farid, Mujahid | Rāshid, Saʻīd | Ali, Shafaqat | Rizwan, Muhammad | Tauqeer, Hafiz Muhammad | Bukhari, Syed Asad Hussain
Phytoextraction is a cost-effective and eco-friendly technique for the removal of pollutants, mainly heavy metal(loids) especially from polluted water and metal-contaminated soils. The phytoextraction of heavy metals is, in general, limited due to the low availability of heavy metals in the growth medium. Organic chelators can help to improve the phytoextraction by increasing metal mobility and solubility in the growth medium. The present research was carried out to examine the possibility of citric acid (CA) in improving chromium (Cr) phytoextraction by Lemna minor (duckweed). For this purpose, healthy plants were collected from nearby marsh and grown in hydroponics under controlled conditions. Initial metal contents of both marsh water and plant were measured along with physico-chemical properties of the marsh water. Different concentrations of Cr and CA were applied in the hydroponics in different combinations after defined intervals. Continuous aeration was supplied and pH maintained at 6.5 ± 0.1. Results showed that increasing concentration of Cr significantly decreased the plant biomass, photosynthetic pigments, leaf area, and antioxidant enzyme activities (like catalase, ascorbate peroxidase, superoxide dismutase, peroxidase). Furthermore, Cr stress increased the Cr concentrations, electrolyte leakage, hydrogen peroxide, and malondialdehyde contents in plants. The addition of CA alleviated the Cr-induced toxicity in plants and further enhanced the Cr uptake and its accumulation in L. minor. The addition of CA enhanced the Cr concentration in L. minor by 6.10, 26.5, 20.5, and 20.2% at 0, 10, 100, and 200 μM Cr treatments, respectively, compared to the respective Cr treatments without CA. Overall, the results of the present study showed that CA addition may enhance the Cr accumulation and tolerance in L. minor by enhancing the plant growth and activities of antioxidant enzymes.
اظهر المزيد [+] اقل [-]Mesorhizobium bacterial strains isolated from the legume Lotus corniculatus are an alternative source for the production of polyhydroxyalkanoates (PHAs) to obtain bioplastics النص الكامل
2017
Marcos-García, Marta | García-Fraile, Paula | Filipová, Alena | Menéndez, Esther | Mateos, Pedro F. | Velázquez, Encarna | Cajthaml, Tomáš | Rivas, Raúl
Polyhydroxyalkanoic acids (PHAs) are natural polyesters that can be used to produce bioplastics which are biodegradable. Numerous microorganisms accumulate PHAs as energy reserves. Combinations of different PHAs monomers lead to the production of bioplastics with very different properties. In the present work, we show the capability of strains belonging to various phylogenetic lineages within the genus Mesorhizobium, isolated from Lotus corniculatus nodules, to produce different PHA monomers. Among our strains, we found the production of 3-hydroxybutyrate, 3-hydroxyvalerate, 3-hydroxydodecanoate, and 3-hydroxyhexadecanoate. Most of the PHA-positive strains were phylogenetically related to the species M. jarvisii. However, our findings suggest that the ability to produce different monomers forming PHAs is strain-dependent.
اظهر المزيد [+] اقل [-]The significance of renewable energy use for economic output and environmental protection: evidence from the Next 11 developing economies النص الكامل
2017
Paramati, Sudharshan Reddy | Sinha, Avik | Dogan, Eyup
Increasing economic activities in developing economies raise demand for energy mainly sourced from conventional sources. The consumption of more conventional energy will have a significant negative impact on the environment. Therefore, attention of policy makers has recently shifted towards the promotion of renewable energy generation and uses across economic activities to ensure low carbon economy. Given the recent scenario, in this paper, we aim to examine the role of renewable energy consumption on the economic output and CO₂ emissions of the next fastest developing economies of the world. The study employs several robust panel econometric models by using annual data from 1990 to 2012. Empirical findings confirm the significant long-run association among the variables. Similarly, results show that renewable energy consumption positively contributes to economic output and has an adverse effect on CO₂ emissions. Given our findings, we suggest policy makers of those economies to initiate further effective policies to promote more renewable energy generation and uses across economic activities to ensure sustainable economic development.
اظهر المزيد [+] اقل [-]Experimental assessment of non-edible candlenut biodiesel and its blend characteristics as diesel engine fuel النص الكامل
2017
Imdadul, H. K. | Zulkifli, N. W. M. | Masjuki, H. H. | Kalam, M. A. | Kamruzzaman, M. | Rashed, M. M. | Rashedul, H. K. | Alwi, Azham
Exploring new renewable energy sources as a substitute of petroleum reserves is necessary due to fulfilling the oncoming energy needs for industry and transportation systems. In this quest, a lot of research is going on to expose different kinds of new biodiesel sources. The non-edible oil from candlenut possesses the potential as a feedstock for biodiesel production. The present study aims to produce biodiesel from crude candlenut oil by using two-step transesterification process, and 10%, 20%, and 30% of biodiesel were mixed with diesel fuel as test blends for engine testing. Fourier transform infrared (FTIR) and gas chromatography (GC) were performed and analyzed to characterize the biodiesel. Also, the fuel properties of biodiesel and its blends were measured and compared with the specified standards. The thermal stability of the fuel blends was measured by thermogravimetric analysis (TGA) and differential scan calorimetry (DSC) analysis. Engine characteristics were measured in a Yanmar TF120M single cylinder direct injection (DI) diesel engine. Biodiesel produced from candlenut oil contained 15% free fatty acid (FFA), and two-step esterification and transesterification were used. FTIR and GC remarked the biodiesels’ existing functional groups and fatty acid methyl ester (FAME) composition. The thermal analysis of the biodiesel blends certified about the blends’ stability regarding thermal degradation, melting and crystallization temperature, oxidative temperature, and storage stability. The brake power (BP), brake specific fuel consumption (BSFC), and brake thermal efficiency (BTE) of the biodiesel blends decreased slightly with an increasing pattern of nitric oxide (NO) emission. However, the hydrocarbon (HC) and carbon monoxides (CO) of biodiesel blends were found decreased.
اظهر المزيد [+] اقل [-]Biodegradation of 2,2′,4,4′-tetrabromodiphenyl ether (BDE-47) by Phanerochaete chrysosporium in the presence of Cd2+ النص الكامل
2017
Cao, Yajuan | Yin, Hua | Peng, Hui | Tang, Shaoyu | Lu, Guining | Dang, Zhi
Aerobic biodegradation of 2,2′,4,4′-tetrabrominated diphenyl ether (BDE-47) by Phanerochaete chrysosporium in the presence of Cd²⁺ was investigated in this study. The results showed that P. chrysosporium could effectively degrade BDE-47, and its extracellular enzyme played an important role in the process of decomposition. BDE-47 biodegradation by fungi was more tolerant than extracellular enzyme in the presence of Cd²⁺. Also, both of the activity of two typical enzymes, MnP and LiP, descended with ascended Cd²⁺ concentration. Based on the four mono-hydroxylated PBDEs (5-OH-BDE-47, 4′-OH-BDE-17, 6-OH-BDE-47, and 2′-OH-BDE-28) and two bromophenols (2,4-DBP, 4-BP) detected, three possible degradation pathways were proposed, inferring that BDE-47 was more easily to transform via hydroxylation. With addition of Cd²⁺, the types of degradation products did not change, merely a variation of the content of these products observed. Meanwhile, the major metabolites of BDE-47, bromophenol compounds, have been found to be transformed or even mineralized by P. chrysosporium quickly, which also helped better explain why the amounts of BDE-47 decomposed did not match with that of the metabolites detected.
اظهر المزيد [+] اقل [-]Composting plant leachate treatment by a pilot-scale, three-stage, horizontal flow constructed wetland in central Iran النص الكامل
2017
Bakhshoodeh, Reza | Alavi, Nadali | Paydary, Pooya
Handling and treatment of composting leachate is difficult and poses major burdens on composting facilities. The main goal of this study was to evaluate usage of a three-stage, constructed wetland to treat leachate produced in Isfahan composting facility. A pilot-scale, three-stage, subsurface, horizontal flow constructed wetland, planted with vetiver with a flow rate of 24 L/day and a 15-day hydraulic retention time, was used. Removal of organic matter, ammonia, nitrate, total nitrogen, suspended solids, and several heavy metals from Isfahan composting facility leachate was monitored over a 3-month period. Constructed wetland system was capable of efficiently removing BOD₅ (87.3%), COD (74.5%), ammonia (91.5%), nitrate (87.9%), total nitrogen (87.8%), total suspended solids (85.5%), and heavy metals (ranging from 70 to 90%) from the composting leachate. High contaminant removal efficiencies were achieved, but effluent still failed to meet Iranian standards for treated wastewater. This study shows that although a three-stage horizontal flow constructed wetland planted with vetiver cannot be used alone to treat Isfahan composting facility leachate, but it has the potential to be used as a leachate pre-treatment step, along with another complementary method.
اظهر المزيد [+] اقل [-]The acute toxicity of bisphenol A and lignin-derived bisphenol in algae, daphnids, and Japanese medaka النص الكامل
2017
Li, Dan | Bi, Ran | Chen, Hongxing | Mu, Lei | Zhang, Lina | Chen, Qin | Xie, Haibo | Luo, Yongju | Xie, Lingtian
Risk assessing newly synthesized chemicals prior to their applications is extremely important, if we want to ensure substitution of risky chemicals with more benign ones. During the past two decades, many analogs of bisphenol A (BPA) have been manufactured, while their toxicity remains less studied. The aim of this study was to compare the acute toxicity of a synthesized lignin-derived BPA (LD-BP) with that of BPA in representative aquatic organisms including two algal species (Chlorella pyrenoidosa and Scenedesmus obliquus), a cladoceran species (Daphnia magna), and the Japanese medaka (Oryzias latipes). The results revealed that the two algal species showed different responses to the two chemicals. For C. pyrenoidosa, both BPA and LD-BP stimulated growth within 48 h of exposure, except for the 50 mg L⁻¹ of LD-BP treatment. After 96 and 144 h of exposures, BPA stimulated the growth of C. pyrenoidosa at low-exposure concentrations but inhibited its growth at high concentrations, while LD-BP caused a concentration-dependent response in C. pyrenoidosa. S. obliquus exhibited a monotonic concentration-response curve for both BPA and LD-BP exposures. For both D. magna and O. latipes, concentration-responses were monotonic with 96 h–LC₅₀ of BPA and LD-BP of 11.7 and 5.0 mg L⁻¹ and 9.4 and 4.1 mg L⁻¹, respectively. Our results demonstrate that LD-BP is more toxic than BPA in the representative aquatic organisms, and it can pose higher ecological risk to the aquatic ecosystem than BPA.
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