Origin of raised maternal serum alpha-fetoprotein levels in second-trimester oligohydramnios

Concanavalin A (Con A) subtyping of alpha-fetoprotein (AFP) revealed higher concentrations of AFP non-reactive with Con A in sera of 12 pregnant women with second-trimester oligohydramnios and raised total serum AFP levels than in sera of 42 pregnant women with raised total serum AFP levels and a normal amniotic fluid volume. This suggests that in oligohydramnios the origin of excess AFP in the maternal compartment is amniotic fluid. It is proposed that oligohydramnios and the associated raised maternal serum AFP levels are caused by damage of the fetal membranes prior to 16 weeks of gestation resulting in leakage of amniotic fluid to the decidual tissue and resorption in the maternal circulation.     

Green energy generation by pressure retarded osmosis: State of the art and technical advancement—review

Pressure-retarded osmosis (PRO) is a method for converting salinity gradients to power by allowing water to flow through a semi-permeable membrane against an applied hydraulic pressure. PRO already has a long history, starting from the middle of the last century, and has rapidly improved in recent years. In this paper, we present a historical development of PRO since its inception: the development of this renewable energy process has gone through several stages, depending on technological developments, worldwide energy demands, and environmental concerns. The technological progress of the process is also studied, as well as its cost viability and environmental impact. Finally, some ideas to further develop the PRO process and mitigate its detrimental effects are discussed.     

Uptake of cadmium into cells in culture∗

Cadmium has been recognized as pollutant of the environment for many years and numerous studies on its toxic effects have been carried out. Little, however, is known about its metabolic behaviour e.g. why the metal is accumulated so extremely rapidly into the organs of men and animals. Since the study of the individual metabolic steps is very difficult in vivo cell cultures may be used to obtain first indications of what happens in the whole animal.

We used CHO cells in monolayer culture to study the conditions under which the uptake of cadmium occurs. From serumfree medium the metal is accumulated rapidly in the cells. The uptake is inhibited very strongly by the presence of serum or albumin. Accumulation occurs against a concentration gradient and is dependent on the incubation temperature. Below 10°C no cadmium uptake is seen. Several substances which are known to affect cell metabolism have been used to influence cadmium accumulation. Neither inhibitors of energy production nor microtubule or microfilament disruptors showed any substantial effect. In contrast SH‐group blocking agents markedly reduced cadmium uptake.

The results show that cadmium uptake does not occur by passive diffusion but by some active mechanism.     

Ion exchange membrane-assisted electro-activation of aqueous solutions: Effect of the operating parameters on solutions properties and system electric resistance

The properties of electro-activated (EA) aqueous solutions as well as the dynamics of their changes were considered in the current study using aqueous solutions of NaCl and NaHCO₃. The concentrations of the salt solutions were 0.5, 0.25, 0.125 and 0.05 M. The tests were performed at the DC current densities of 25, 37.5, and 50 Å/m². The electro-activation reactor consisted of three individual cells assembled together and separated by anion-exchange (AEM) and cation-exchange (CEM) membranes. During the experiments, four configurations of the membrane placements and solutions concentrations were studied. The obtained results showed the dynamics of the electro-activation process that allows obtaining electro-activated solutions with targeted properties such as pH and oxydo-reduction potential (ORP). It was possible to obtain electro-activated solutions at the anodic side (acid anolyte) with pH of 3.0, 3.5, and 4.0 and ORP of +1100 ± 15 mV when NaCl solution was used as electrolyte. Furthermore, several types of electro-activated solutions with high redox potential (ORP = +921 ± 12 mV) and neutral pH (6.48 ± 0.05) were obtained on the anode side when sodium carbonate was used. At the same time, two types of solutions, one with acid pH (2.14 ± 0.14) and the other one with alkaline pH (10.46 ± 0.03) with ORP = +689 ± 10 and 110 ± 21 mV, respectively, were obtained in the central compartment which considered as electro-activated solutions obtained by means of noncontact electro-activation.     

乙醇对含水层中燃油芳香烃内在生物修复的潜在风险

内在生物修复,是在没有工程措施促进的情况下利用土著微生物降解含水层内灾害性物质的一种修复技术,在燃油烃污染管理方面具有显著的成本效益。该技术需要确定自然衰减过程,并能够继续提供有效的风险保护。针对燃油污染含水层,北美与欧洲认为内在生物修复是值得优先考虑的应用技术。然而,随着乙醇燃油的推广使用,我国在应用这样的经验时需要考虑乙醇的潜在影响。现有的文献研究表明乙醇存在能够阻止燃油主要污染物芳香烃(BTEX)的生物降解,降低水环境的pH值,并可能增强BTEX在水中的溶解性,或存在对生物的毒性,或因为乙醇降解降低介质的渗透性能。因此,需要更好地认识乙醇的潜在风险,为发展乙醇燃油污染含水层修复策略提供科学依据。     

Explicit and implicit coupling during solute transport through clay membrane barriers

Simulations of salt (KCl) flux through a 1-m-thick clay membrane barrier (CMB) based on coupled solute transport theory are compared to simulated fluxes based on traditional advective-dispersive transport theory. The simulations are based on measured values for the effective salt-diffusion coefficient (Ds*) and chemico-osmotic efficiency coefficient (omega) for a bentonite-based barrier material subjected to KCl solutions. The results indicate that the exit salt flux is reduced due to both explicit coupling (hyperfiltration and chemico-osmotic counter-advection) and an implicit coupling effect resulting from the decrease in Ds* due to a decrease in the apparent tortuosity factor, tau a, with an increase in omega. Implicit coupling is shown to be more significant than explicit coupling for reducing and retarding salt flux through a CMB under diffusion-dominated conditions. Failure to account for the implicit coupling effect may result in unrealistic results, such as the existence of salt flux through a perfect (ideal) clay membrane (i.e., omega=1).     

Photoreduction of parathion ethyl †

Photodegradation of parathion ethyl in presence of unsaturated biomolecules takes place by sufficient reduction of the phenyl nitro group. Main products are N,0‐dialkenyl hydroxylamino, cis/trans azo, and azoxy derivatives of parathion.     

MWNTs/TiO2/聚酯功能复合膜吸附及其净化性能

以聚酯工业滤布为基膜,采用溶胶凝胶和浸渍方法制备了具有吸附-光催化功能的多壁碳纳米管(MWNTs)/TiO2涂层的复合膜,该复合膜对模拟水样低浓度(10mg/L)的双酚A具有较高吸附性能.随着复合膜上负载二氧化钛中的MWNTs的比例(17.6%,29.9%,和46.0%)增加,吸附去除率显著提高;吸附饱和的复合膜上的污染物双酚A可通过20W 紫外灯(l=254nm)照射Fenton氧化反应去除.吸附实验和HPLC分析表明,除了超声处理会引起浸渍负载的材料脱落外,复合膜吸附性能恢复较好.     

木薯乙醇-汽油混合燃料生命周期排放多目标优化研究

建立了木薯乙醇-汽油混合燃料生命周期排放单目标和多目标优化模型.以生命周期CO,NO_x,PM,HC,SO_x,CO₂排放为优化目标,对木薯乙醇-汽油混合燃料生命周期排放进行了单目标及多目标优化,并进行了灵敏度分析.结果表明:多目标优化后木薯乙醇-汽油混合燃料的混合比例为63%.与原始值相比,多目标优化后生命周期CO排放略有升高,NO_x升高15%,PM升高19%;生命周期HC、SO_x和CO₂分别降低8%、50%和21%.     

GO-TiO2改性中空纤维膜的制备条件及抗污染性能研究

以氧化石墨烯(GO)与纳米二氧化钛(TiO_2)为改性剂,采用界面聚合法与抽滤吸附结合,对聚偏氟乙烯中空纤维超滤膜(简称原膜)进行表面改性,得到新型纳米改性膜(简称GO-TiO_2改性膜).研究改性膜的制备工艺条件及其对腐殖酸(HA)的吸附截留性能与抗污染特性.结果表明:(1)最佳制备工艺条件为:钛酸丁酯2 m L、GO 1 mg、间苯二胺1%(质量分数)、间苯二胺浸泡时间8 min、均苯三甲酰氯0.2%(质量分数)、均苯三甲酰氯浸泡时间10 min;(2)亲水性提高显著,亲水性表面为GO-聚酰胺-TiO_2复合结构,改性膜接触角由80.6°±1.8°下降到38.6°±1.2°;(3)抗污染性能提高明显.改性膜通量总衰减率由改性前的51.2%下降到35.6%,过滤周期约为原膜的2.5倍;反冲洗后膜通量恢复率由69%提高到96%.