Higher-efficiency for combined photovoltaic-thermoelectric solar power generation

Solar energy application in a large spectrum has the potential for high-efficiency energy conversion. Though, solar cells can only absorb photon energy of the solar spectrum near their band-gap energy, and the remaining energy will be converted into thermal energy. The use of the thermoelectric generator becomes a necessity for convert this thermal energy dissipated so as to increase efficiency conversion.

This paper analyses the feasibility of photovoltaic-thermoelectric hybrid system and reviews their performance in order to optimize harvested energy. Regarding the thermoelectric effect, a new method of the ambient energy harvesting is presented. This method combines thermoelectric generators and the effects of heat sensitive materials associated to photovoltaic cells in phase change for generating both energy day and night. Experimental measures have been conducted primarily in laboratory conditions for a greater understanding of hybridization phenomena under real conditions and to test the actual performance of devices made. Results show that the hybrid system can generate more power than the simple PV and TEG in environmental conditions. This hybrid technology will highlight the use of renewable energies in the service of the energy production.     

Oxidative and genotoxic effects of bisphenol A on primary gill cell culture of Lake Van Fish (Alburnus tarichi Güldenstädt, 1814)

Lake Van is the largest lake in Turkey. The lake limits lifespan due to its high pH and brackish water. For this reason, only a single species of fish (Van Fish) is living in the lake that has been adapted to these conditions. In the present study, we investigated the total oxidant status (TOS), total antioxidant status (TAS), malondialdehyde (MDA) level and DNA damage effect of bisphenol A (BPA) (10^?7, 10^?6 and 10^?5?M) on primary gill cell culture of Van Fish for 24 and 48?h of incubation periods. TAS levels were not changed when compared to those of the control group, but TOS levels were decreased in both 24 and 48?h. The MDA level increased only at the highest concentration (10^?5) at the end of 12 and 24?h (p?.05). DNA damage increased only at the 10^?5?M concentration after 48?h. At the end of the experiment, BPA exposure caused lipid peroxidation and genotoxic effect. These results indicate that high levels of BPA exposure induced oxidative stress and DNA damage by time- and concentration-dependent fashion in the gill cell culture of Van Fish. Gill cell culture is a useful model for the rapid identification of the harmful effects of chemicals in the aquatic environment.     

Epigenetic effect of long-term bisphenol A exposure on human breast adenocarcinoma cells

In this research, epigenetic effects of bisphenol A (BPA) on human breast cancer MCF-7 cells were analyzed. Genome-wide DNA methylation and gene expression were analyzed in MCF-7 cells exposed to BPA (10^?5 and 10^?6 mol/L for 5 weeks). No significant changes in the global level of 5-methyl-2′-deoxycytidine and 5-hydroxymethyl-2′-deoxycytidine were observed. DNA methylation profiling analysis indicated that BPA exposure resulted in the hypermethylation of FOXK2, LKB1, LMX1A and CUGBP2 and the hypomethylation of PTPRN2, TRIM27, BCAS3 and ZNF423. Decreased expression of apoptosis genes (P38 and BCL2L1) and increased expression of chemokine (Cxcl2 and ccl20) were detected. Changes of these genes were speculated to affect the ERα-related cell growth as well as cell apoptosis.     

连续流双室微生物燃料电池处理工业废水

以实际中药废水作为阳极基质、实际含镉废水作为阴极电解液,构建了连续流双室微生物燃料电池(MFC),考察了其产电性能及对两种废水的处理效果。78 d的运行数据表明:系统可实现最大输出电压417mV、最大体积功率密度11.8 W/m3,最大体积功率密度运行条件下的库伦效率为18.5%;在阳极进水有机物浓度变化较大的情况下,实现了阳极对中药废水中有机物的有效去除,平均COD去除率为81.5%;阴极对含镉废水中Cd2+的去除率为79.4%～84.8%。这表明MFC同步处理中药废水及重金属废水具有一定的可行性。     

Mitochondrial toxicity and in vitro biological effects of ambient PM2.5 from an urban site in China

Abstract

The roles of PM_2.5-induced mitochondrial damage and oxidative stress on mast cell degranulation were examined in vitro. Mast cells were treated with suspensions of PM_2.5 in Dulbecco’s modified Eagle’s medium at concentrations from 25 to 200?mg/L in the absence or presence of 10?mmol/L N-acetyl-L-cysteine. Biological effects and mitochondrial function were assessed by determining cell viability, β-hexosaminidase release, interleukin-4 secretion, reactive oxygen species generation, adenosine triphosphate production, potential alteration of mitochondrial membrane, and activities of mitochondrial electron transport chain complexes I and III. Exposure of mast cells to PM_2.5 induced reduction of adenosine triphosphate production, collapse of mitochondrial membrane potential, and inhibition of the activity of complex III. Co-treatment of mast cells exposed to PM_2.5 with N-acetyl-L-cysteine attenuated cytotoxicity and the production of reactive oxygen species, and decreased the release of β-hexosaminidase and interleukin-4. Evidently, PM_2.5-induced oxidative stress plays an essential role in mitochondrial toxicity and mast cell activation.     

一株苯酚降解菌的分离鉴定及响应面法优化其固定化

从太原市焦化厂废水活性污泥中分离、筛选出一株苯酚降解细菌,经生理生化反应和16S rRNA鉴定,该菌株为Diaphorobacter属细菌,命名为PD-07.代谢机制研究表明,苯酚可诱导该菌合成邻苯二酚2,3-加氧酶降解苯酚.为了提高该菌株对苯酚的降解率,以海藻酸钙为材料,对该菌株进行包埋固定化研究.首先采用Plackett–Burman实验设计筛选出影响固定化菌株苯酚降解率的关键因素,然后采用最陡爬坡实验逼近最大苯酚降解率响应区域.最后用Box–Behnken实验设计及响应面回归分析,应用二次方程对实验数据进行拟合得,拟合曲线与实验实测值相关性良好,最佳条件为海藻酸钠浓度3.83%(m/V)、CaCl2 0.3mol/L、菌胶比1:26.73、固定化时间2h、摇床转速180r/min、培养温度30℃、初始pH值7.2、液固比4.86:1,在此条件下苯酚降解率可达96.89%.     

Influence of hypothyroidism on oxidative stress,c-Fos expression,cell cycle,and apoptosis in rats testes

The molecular basis of male reproduction for cross-regulation between androgen and thyroid hormone axes is still rudimentary. This study aims to define a possible mechanism of hypothyroidism-induced reproductive influence with respect to sex hormone, mineral, sperm motility, oxidative stress, c-Fos expression, cell cycle, and apoptosis in rat testes. The Wistar rats were randomly divided into control group (NS) and hypothyroidism group [1 ml/100g BW/day, 0.1% propylthiouracil (PTU)] by intragastric gavage for 60 days. Blood samples were collected to measure the serum levels. The epididymis was excised to measure sperm motility and testes were excised to measure mineral, oxidative stress, c-Fos expression, cell cycle, and apoptosis. After 60 days, body weight, relative testes weight, triiodothyronine, and total thyroxine were all significantly decreased, whereas thyroid stimulating hormone was increased in the hypothyroidism group. A significant increase in sex hormone level of estradiol (E2) and significant decreases in testosterone (T) and T/E2 ratio were observed following PTU treatment. And sperm quality was also significantly changed. There were significant decreases in the contents of calcium (Ca²⁺) and zinc (Zn²⁺). On the other hand, malondialdehyde and hydrogen peroxide contents significantly increased, whereas the activity of superoxide dismutase, catalase and nitric oxide synthase and nitric oxide content significantly decreased in hypothyroid rats. The mRNA and protein expressions of c-Fos decreased significantly. The cell percentage in G0/G1 phase increased significantly, whereas decreased significantly in S and G2/M phases. Also, a significant increase in testicular cell apoptosis was observed in hypothyroid-treated rats. These results suggested that hypothyroidism could affect reproductive function in the form of changed sex hormone levels, sperm motility and testicular Ca²⁺ and Zn²⁺, and enhanced oxidative stress leading to c-Fos abnormal expression and increased apoptosis.     

双室微生物燃料电池处含银废水的产电性研究

以剩余污泥为阳极底,糖蜜废水为基质,Ag Cl废水为阴极电子受体,构建了双室微生物燃料电池(Two-chamber Microbial Fuel Cell,简称MFCs),并研究了电池的产电特性、库仑效率及金属去除率.结果表明:Ag+不仅可以作为阴极电子受体,而且还能稳定产电,外电阻为1000Ω时,获得的最大电压为514.5 m V,最大功率密度为65.82 m W·m-2.在阴极实现了对废水中Ag+的去除,最大去除率可达71.6%,而且Ag+浓度为2000 mg·L-1时,回收金属银单质质量为197.66 g.在阳极对废水的处理效果也很显著,库仑效率最高为2.66%,COD去除率最大为81.22%.     

一株产电菌嗜根考克氏菌(Kocuria rhizophila)的分离及其产电性能优化

本研究以天津泰达污水处理厂污泥浓缩间的污泥为接种物,启动并运行了微生物燃料电池(MFCs).从富集的阳极生物膜上分离得到了一株纯培养的微生物菌种,命名为P2-A-5.研究发现,菌株P2-A-5的16S rDNA序列与菌株Kocuria rhizophila DC2201具有100%的同源性,结合该菌的形态特征和生理生化实验,将其归属为嗜根考克氏菌(Kocuria rhizophila).通过化学剂处理、底物种类和浓度的优化,进一步提高其在微生物燃料电池中的产电性能.结果表明,菌株K.rhizophila P2-A-5经0.5 mg·L-1溶菌酶处理45 min后,接种到以2.0 g·L-1海藻糖为底物的阳极液中运行MFCs,其功率密度达到314.8 m W·m-2,比优化前(74.9 m W·m-2)提高了320.3%.这是首次对K.rhizophila种内微生物产电性能及其在微生物燃料电池中应用的报道,其成果对于丰富产电微生物的多样性,挖掘更多具有高电化学活性的微生物菌种,提高其产电性能具有重要的理论意义.     

The Kinetics of Interesterfication on Waste Cooking Oil (Sunflower Oil) for the Production of Fatty Acid Alkyl Esters using a Whole Cell Biocatalyst (Rhizopus oryzae) and Pure Lipase Enzyme

Recent research and technology have provided promising outcomes to rely on biodiesel as the alternative and conventional source of fuel. The use of renewable sources constitutes the main stream of research. Waste Cooking Oil (WCO) was used for biodiesel production in this study. Lipase enzyme producing fungi Rhizopus oryzae 262 and commercially available pure lipase enzyme were used for comparative study in the production of FAAE. The whole cell biocatalyst and pure enzyme were immobilized using calcium alginate beads. It was prepared by optimizing with different molar ratios of calcium chloride and different percent sodium alginate. Entrapment immobilization was done for whole cell biocatalyst. PE was also immobilized by entrapment for the transesterification reaction. Four different solvents methanol, ethanol, n-propanol, n-butanol were used as the acyl acceptors. The reaction parameters like temperature, molar ratio, reaction time, and amount of enzyme to be used were also optimized for methanol alone. The same parameters were adopted for the other acyl acceptors too. Among the different acyl acceptors, methanol whose reaction parameters were optimized showed maximum conversion of triglycerides to FAAE - 94% with PE and 84% with WCB. On the whole, PE showed better catalytic converting ability with all the acyl acceptor compared to WCB, further study, it was observed that three consecutive and reversible reactions occurred in the interesterification of triglycerides. So, a kinetic model based on Michaelis-Menten equation with competitive substrate inhibition was used to find the maximum reaction rate V_i for the four solvents using pure enzyme and WCB.