Arbuscular mycorrhizal fungi involvement in zinc and cadmium speciation change and phytoaccumulation

Over the past few years, there has been a greater study and understanding of the application of phytoremediation to remediate contaminated soil. The enhancement of phytoaccumulation of heavy metals—zinc (Zn), cadmium (Cd), arsenic (As), and selenium (Se)—in plants has been shown by inoculation of roots using arbuscular mycorrhizal fungi (AMF). This article presents the results of in vitro lab experiments conducted to verify the effects of AMF ( Glomus intraradices) hyphae on speciation of essential Zn and nonessential Cd heavy metals in order to change these metals from a water‐ insoluble carbonate to a soluble and phytoavailable form. Results show that in the presence of heavy metals in a nonavailable form to plants, endomycorrhizal hyphae can change the metal from carbonate to a water‐ soluble species. This phenomenon is more apparent with a nonessential (Cd) than with an essential metal (Zn). Zn saturation is reached in the G. intraradices colonized roots at around 400 ppm, independently of initial ZnCO₃ concentrations. Cd saturation is not reached; in the lower Cd treatment, the plant/media metal ratio is 3:1, and in the higher treatment, the ratio is 1:1. © 2005 Wiley Periodicals, Inc.     

Prenatal diagnosis of female monozygotic twins discordant for Turner syndrome: implications for prenatal genetic counselling

We describe a set of monozygotic (MZ) female twins, one of whom presented with a typical Turner syndrome (TS) phenotype and the other a normal female phenotype. Prenatal fetal ultrasonographic examination showed a monochorial diamniotic pregnancy with a hygroma colli and growth delay in Twin A and no anomalies in Twin B. Karyotypic analysis performed on fetal blood samples demonstrated a 46,XX/45,X (23/2) mosaicism in Twin A and a normal 46,XX chromosome constitution in Twin B. At birth, Twin A presented with a typical TS and Twin B had a normal female phenotype. Postnatal cytogenetic investigation of blood lymphocytes showed the same 46,XX/45,X mosaicism in both twins: 46,XX/45,X (40/7) in Twin A and 46,XX/45,X (40/5) in Twin B. Further investigations at the age of 10 months showed in Twin A a 46,XX/45,X (98/2) mosaicism in lymphocytes and 100% of 45,X (50 analysed cells) in fibroblasts, and in Twin B a normal 46,XX (100 analysed cells) chromosome constitution in lymphocytes but a mild 46,XX/45,X (78/2) mosaicism in fibroblasts. Monozygosity was confirmed by molecular analysis. To our knowledge, this is the first report of prenatal diagnosis of MZ female twins discordant for TS. Review of reported sets of MZ female twins (eight cases) or triplets (one case) discordant for TS shows, as in the present case, that the phenotype correlates better with the chromosomal distribution of mosaicism in fibroblasts than in lymphocytes. In the blood of MZ twins chimerism may modify the initial allocation of the mosaicism. These results suggest that, in cases of prenatal diagnosis of MZ female twins discordant for TS, the phenotype of each twin would be better predicted from karyotype analysis of cells from amniotic fluid than from fetal blood. Copyright © 2002 John Wiley & Sons, Ltd.     

Prenatal diagnosis of primary anophthalmia with a 3q27 interstitial deletion involving SOX2

We report an interstitial deletion of chromosome 3q26-q28 in a fetus in which anophthalmia had been detected prenatally. FISH analysis, using BAC clones encompassing the SOX2 locus, showed that SOX2 gene was involved in the chromosomal breakpoint of the deletion. This case confirms that haploinsufficiency for SOX2 plays a crucial role in human eye development and emphasizes the necessity of careful chromosomal analysis, including FISH analysis of the 3q region, in case of prenatal discovery of anophthalmia. Copyright © 2004 John Wiley & Sons, Ltd.     

The African electric power sector in the context of an acute financial crisis

There has been a sharp downturn in the building of electricity production and distribution facilities in sub-Saharan Africa due to economic and financial constraints. In part this was due to the steady decline in GDP in sub-Saharan Africa throughout the 1980s. The slackening growth of demand and the continuing decline in existing generating capacity have led to a shift in emphasis towards the restructuring of electricity companies, management improvements and the rehabilitation of existing plants rather than new investment in production and distribution facilities. Nevertheless, valid doubts remain as to the ability of the African electricity sector to mobilize sufficient resources in the medium term to ensure its development.     

Monochorionic and dichorionic twin pregnancies discordant for fetal anencephaly: a systematic review of prenatal management options

The aim of this study was to evaluate the effect of selective feticide (SF) compared to expectant management (EM) on perinatal outcome in dichorionic and monochorionic twins discordant for anencephaly. For this purpose, we conducted a systematic review of literature and added ten unpublished cases. As a result, we found that in dichorionic twins, mean gestational age (GA) at birth in the SF group was 38.0 weeks versus 34.9 weeks (P = 0.0002). Mean birth weight was 2922 g in the SF group versus 2474 g (P = 0.03). In monochorionic twins, mean GA at birth was 35.2 weeks versus 32.7 weeks (P = 0.1). Mean birth weight was 2711 g versus 1667 g (P = 0.0001). We conclude that while SF does not reduce perinatal mortality, it does result in significantly longer gestations and higher birth weight, and appears to be the management of choice in dichorionic twins discordant for anencephaly. In monochorionic twins, SF also increases birth weight, but in view of the complexity of this group, no clear recommendations can be made. Copyright © 2008 John Wiley & Sons, Ltd.     

Efficiency and degradation products elucidation of the photodegradation of mefenpyrdiethyl in water interface using TiO2 P-25 and Hombikat UV100

The photodegradation of mefenpyrdiethyl (MFD), an herbicide safener, was investigated in aqueous suspensions by using Degussa P-25 and Hombikat UV100 titanium oxide under simulated sunlight irradiation. The effects of initial concentration of the herbicide, pH, catalysts and hydrogen peroxide doses as well as their combinations were studied and optimized. Accordingly, the kinetic parameters were determined and the effectiveness of the processes was assessed by calculating the rate constants. A pseudo first-order kinetics was observed. Under experimental conditions, the degradation rate constants were strongly influenced using P-25 and no noticeable effect was observed for Hombikat UV100. DFT calculations with B3LYP/6-311+G(2d,p)//B3LYP/6-31+G(d,p) level of theory were performed to check whether significant conformational changes occur when the charge state of the MFD substrate changes and whether these changes could play a role in the dependency of photodegradation rate constant on the studied pH. High resolution mass spectrometry (FT-ICR/MS) was implemented to identify the main degradation products.     

Cyclodextrins: a new efficient absorbent to treat waste gas streams

Volatile Organic Compounds (VOCs) in the air provoke health and environmental concerns. This paper focuses on the absorption method to treat industrial polluted air loaded with VOCs. The key variable of this treatment being the choice of a suitable liquid absorbent, the aim of this research work is to investigate the effectiveness and the regeneration of a new potential family of absorbent: cyclodextrins (CDs). All CDs derivatives tested are able to decrease the Henry's law constant of toluene: a reduction of volatility up to 95% may be obtained, depending on CD nature and concentration. Moreover, absorption experiments show that beta-CD, which presents the highest absorption ability, is 250 time more efficient than water. The absorption efficiency is not totally correlated with static experiments, suggesting that, in addition to Henry's law constants and inclusion compounds stability, toluene diffusion into such solutions has to be taken into account. It is also to be noted that salt and pH variations seem to have little influence on the absorption capacity of CDs, which may be of great interest for industrial applications. Finally, since production of solid compounds was not observed during these experiments and since temperature decreases the capture ability in a drastic way, regeneration of the washing solution can be achieved by heating the solution in combination with air stripping.     

生命周期评价与社会影响

生命周期评价(LCA)在提供数据、管理工具、软件和方法论中再加之更精确的测定方面已经取得了巨大的进步,然而与此同时仍然还有许多问题要解决.许多这些问题涉及到LCA方法在世界范围内的推广,以及这些方法如何通过建立数据库和按当地需要定制管理工具而适应发展中国家.……