Skeleton and sclerite formation in the precious red coral Corallium rubrum

The carbonate skeleton of the gorgonian coral Corallium rubrum (L.) is composed of both a skeletal axis and numerous sclerites scattered in the mesoglea. Studies carried out on these skeletal elements and their associated tisues using microscopy and X-ray microanalysis, suggest a close relationship between the process of sclerite formation and skeletogenesis. The skeleton is surrounded by an axial epithelium composed of a single cell type. These cells associate intimately with mesogleal sclerites and scleroblasts, incorporating them into a nascent skeleton at the branch tip. Subsequent (sub-apical) growth appears to occur solely through the agency of the axis epithelial cells that serve to physically separate mesogleal sclerites and scleroblasts from contact with the axis. The epithelium is associated with the production of layered calcite crystals and irregular protuberances that constitute the mature, calcareous skeleton. Free sclerites in the mesoglea appear to be the product of multiple cells that are cytologically indistinguishable from those in the axis epithelium. Like the axis, sclerites are produced as layers of calcite crystals with irregular protuberances. The protuberances differ only slightly from those of the axis, and the skeleton is mineralogically indistinguishable from the sclerites. Thus, the skeleton of red coral is not primarily the product of fused sclerites. Instead, we suggest that the axis epithelium treats the incipient skeleton as if it were the core of a single sclerite, and conversely, that the mesogleal scleroblasts of C. rubrum constitute a fragmented axis epithelium.     

Biological oxidation of arsenite: batch reactor experiments in presence of kutnahorite and chabazite

Arsenic represents a threat to all living organisms due to its toxicity which depends on its speciation. This element is carcinogenic, teratogenic and is certainly one of the most important contaminants affecting millions of people around the world. Abiotic and biotic processes control its speciation and distribution in the environment. We have previously shown that a new bacterial strain named ULPAs1 performed oxidation of As(III) (1.33 mM) to As(V) in batch cultures. In order to develop new methods to remove arsenic from contaminated effluents or waste, by bacterial oxidation of As(III) to As(V) followed by its sorption, the conservation of oxidative properties of ULPAs1 was investigated when cultivated in batch reactors in the presence of two solid phases, chabazite and kutnahorite, already used as microorganisms immobilizing materials in biological remediation processes. In parallel, the retention efficiency of these solid phases toward arsenic ions and particularly arsenate was studied. Pure quartz sand was used as a reference material. Kutnahorite efficiently sorbed As(V), chabazite alone performed As(III) oxidation and pure quartz sand did not sorb arsenic at all. The arsenite oxidative properties of ULPAs1 were conserved when cultivated in the presence of quartz or chabazite.     

EXPERIENCE WITH THE 303-208-201 STUDY RELATIONSHIPS1

ABSTRACT: The current 201 study by the Bergen County Sewer Authority illustrates possibilities for improving the currently defined relationships between 201, 208 and 303 studies. The Bergen County Sewer Authority serves 115 square miles in northeast New Jersey, providing sewerage service to 507,000 people in 43 municipalities. Its STP discharges to the Hackensack River, a tidal estuary recently classified as Water Quality Limited, and which receives significant non-plant loading. The subject 201 study is concurrent with 208 and 303 planning by NJDEP. Preliminary evaluations show that detailed 201 work can affect the conclusions of 303 and 208 studies, and that a wider (environmental - social as well as economic) interpretation of cost-effectiveness can demand re-examination of prior assumptions and decisions, a task not typically part of 208–303 work. Increased flexibility is needed in applying 303 and 208 recommendations to defining 201 studies and NPDES permit criteria, particularly in analysis of water use objectives, water quality parameters and future flows, loadings and facility costs. Further, perception of alternatives can be clarified by broadening analysis of costs and control and plant strategies. Inclusion of 201 planning at all stages of regional planning can synergistically improve the total planning process.     

Characterization of Atrazine-Loaded Biodegradable Poly(Hydroxybutyrate-Co-Hydroxyvalerate) Microspheres

Polyhydroxybutyrate-co-hydroxyvalerate microspheres (PHBV-MS) were prepared as a delivery system for the herbicide atrazine (ATZ). Characterization of the system included investigation of in vitro release properties and genotoxicity. ATZ − PHBV-MS particle diameters showed a size distribution range of 1–13 μm. Differential scanning calorimetry analyses indicated that ATZ was associated with the PHBV microparticles. The release profiles showed a different release behavior for the pure herbicide in solution, as compared with that containing ATZ-loaded PHBV-MS. Korsmeyer–Peppas model analyses showed that atrazine release from the microparticles occurred by a combination of diffusion through the matrix and partial diffusion through water-filled pores of the PHBV microparticles. A Lactuca sativa test result showed that the genotoxicity of ATZ-loaded PHBV-MP was decreased in relation to ATZ alone. The results demonstrate a viable biodegradable herbicide release system using atrazine for agrochemical purposes.     

Prenatal diagnosis of ventricular aneurysm: a report of two cases and a review

Ventricular aneurysms have rarely been reported prenatally. Their prognosis is variable depending on factors such as early detection, their relative size in comparison to the ventricular cavity, growth on follow-up, and signs of cardiac failure. In view of the fact that it may be useful to report on additional cases in order to make available further information on aetiology, prognosis and neonatal management, we hereby report on two cases of ventricular aneurysm with good mid-term prognosis. One case of apical aneurysm of the left ventricle was associated with a muscular ventricular septal defect, the features of which are compatible with a fetal myocardial infarction and ventricular septal rupture in absence of coronary artery anomalies as demonstrated by catheterisation. Another case of sub-tricuspidal aneurysm of the right ventricle associated with mitral prolapse appears to be a component of diffuse connective dysplasia. Despite the early gestational age at diagnosis, the large size of the aneurysm and the associated defect, both the infants were asymptomatic in infancy prompting a conservative management. Copyright © 2002 John Wiley & Sons, Ltd.     

Analysing the fate of nanopesticides in soil and the applicability of regulatory protocols using a polymer-based nanoformulation of atrazine

For the first time, regulatory protocols defined in the OECD guidelines were applied to determine the fate properties of a nanopesticide in two agricultural soils with contrasting characteristics. The nanoformulation studied had no effect on the degradation kinetics of atrazine indicating that (1) the release of atrazine from the polymer nanocarriers occurred rapidly relative to the degradation kinetics (half-lives 36–53 days) and/or that (2) atrazine associated with the nanocarriers was subject to biotic or abiotic degradation. Sorption coefficients, derived from a batch and a centrifugation technique at a realistic soil-to-solution ratio, were higher for the nanoformulated atrazine than for the pure active ingredient. Results indicate that the nanoformulation had an effect on the fate of atrazine. However, since the protocols applied were designed to assess solutes, conclusions about the transport of atrazine loaded onto the nanocarriers should be made extremely cautiously. The centrifugation method applied over time (here over 7 days) appears to be a useful tool to indirectly assess the durability of nanopesticides under realistic soil-to-solution ratios and estimate the period of time during which an influence on the fate of the active ingredient may be expected. More detailed investigations into the bioavailability and durability of nanopesticides are necessary and will require the development of novel methods suitable to address both the “nano” and “organic” characteristics of polymer-based nanopesticides.     

Poly[(R)-3-hydroxy butyrate] Melt Processing: Strategy for Prevention of Degradation Reactions

Poly[(R)-3-hydroxy butyrate] (PHB) as well as all the components of the poly[(R)-3-hydroxy alkanoate]s (PHAs) family tend to degrade during processing at temperatures above their melting point via a hydrolytic mechanism induced by moisture attack and a concerted reaction mechanism induced by temperature. Therefore, the PHAs stabilization in the molten state is particularly important for production of biodegradable ecocompatible plastic items of commercial value. In order to refrain the indicated negative degradation effects, PHB was melt processed in a torque rheometer in the presence of a polymeric carbodiimide agent. Processed specimens were characterized by using FTIR, GPC, DSC, TGA and tensile properties. GPC analysis showed that the increase of the additive content in the formulation resulted in an increase of PHB molecular weight. However, decreasing in PHB thermal stability, glass transition temperature and mechanical properties, was observed with the increase of the additive amount. This behaviour most likely arises from the formation of new chemical structures promoted by the presence of the additive aimed at preventing the onset of hydrolitic processes.     

Is PCBs concentration variability between and within freshwater fish species explained by their contamination pathways?

Many chemical, physiological, and trophic factors are known to affect bioaccumulation of polychlorinated biphenyls (PCBs) in biota. Understanding the primary factors affecting fish contamination is critical for predicting and assessing risks to upper-trophic level consumers, including humans. Here we identify PCB contamination pathways that could explain within- and between-species variability in fish concentration levels. Three freshwater river fish species (barbel, chub and bream) were sampled at three sites along the Rhone River (France) where fish consumption is partially prohibited because of PCB levels exceeding the European health-based benchmark. The trophic position was assessed using an innovative approach based on stable isotope analyses and Bayesian inference, which takes into account both isotope data variability and parameter uncertainty. The effect of foraging habitat on fish contamination was addressed using stable isotope mixing models. The fish trophic position and PCB concentrations were found to be unrelated while the exploitation of sediment detrital carbon as a food source appeared to be a critical factor affecting fish contamination. Fish length, PCB concentration of the sediment, and individual fish foraging habitat (exploitation of detrital versus planktonic carbon sources) explained 80% of within- and between-species variability observed in PCB concentrations. These results, obtained for species that have overlapping TPs and exploit different carbon sources, reveal that the important factor in fish PCB contamination is not only what fish consume, but also and essentially the feeding location.