Monitoring the natural attenuation of a sewage sludge toxicity using the Allium cepa test

Appropriate final disposal of sewage sludge (SS) generated by wastewater treatment plants (WWTP) has been considered a serious environmental problem, but also a viable alternative to be applied in agriculture, once SS is rich in organic matter and nutrients. However, SS can be a source of contamination of several toxic agents. Therefore, its use in agriculture requires special care to avoid possible damage to the environment and exposed organisms. Detoxification of toxic wastes can be performed using the monitored natural attenuation, which involves biological, physical and chemical processes that frequently occur in the environment. This study aimed to assess the feasibility of decontaminating SS after different periods of monitored natural attenuation. To this end, samples of SS and associations of soil/SS with proportions of 10, 25 and 50% SS were buried for 0, 2, 6 and 12 months in holes prepared in a place free of contamination. Allium cepa was used as an indicator to assess the efficiency of the natural attenuation process. According to chemical analysis, the SS samples presented a high concentration of m- and p-cresol, especially for samples analyzed after 0 or 2 months of natural attenuation. The microorganisms present in the SS belonged to 17 different genera of bacteria, which varied in the microbial composition among samples. Both, raw SS and aqueous SS extracts induced DNA damage in A. cepa, even when associated with soil. However, this effect was observed to decline during the attenuation period, although significant effects were detected for the highest tested concentration (100% SS) even at the end of this process. These results thus indicated the necessity of applying a stabilization process associating SS and soil for a period of at least 12 months and showed that the studied raw SS is not a viable material for use as a soil reconditioner, even after natural attenuation. A. cepa test proved to be a useful tool to assess the efficiency of SS detoxification process. Therefore, we suggest that the application of SS in agriculture should be approached with caution and that the SS must be previously submitted to methodologies that evaluate its toxic potential.     

Role of diastolic vortices in flow and energy dynamics during systolic ejection

MRI-based computational fluid dynamics simulations were performed in the left ventricles of two adult porcine subjects with varying physiological states (before and after an induced infarction). The hypothesis that diastolic vortices store kinetic energy and assist systolic ejection was tested, by performing systolic simulations in the presence and absence of diastolic vortices. The latter was achieved by reinitializing the entire velocity field to be zero at the beginning of systole. A rudimentary prescribed motion model of a mitral valve was included in the simulations to direct the incoming mitral jet towards the apex. Results showed that the presence or absence of diastolic vortex rings had insignificant impact on the energy expended by walls of the left ventricles for systolic ejection for both the porcine subjects, under all physiological conditions. Although substantial kinetic energy was stored in diastolic vortices by end diastole, it provided no appreciable savings during systolic ejection, and most likely continued to complete dissipation during systole. The role of diastolic vortices in apical washout was investigated by studying the cumulative mass fraction of passive dye that was ejected during systole in the presence and absence of vortices. Results indicated that the diastolic vortices play a crucial role in ensuring efficient washout of apical blood during systolic ejection.     

New Solid Supports Linking Nucleoside Scaffolds

Abstract

An easy and efficient strategy to obtain new nucleoside based solid supports in which the nucleoside moieties have been anchored to the solid support through the nucleobase is here proposed. A simple and efficient solid-phase synthesis of 5′ and 3′-derivatized uridine analogues has so been developed, following methodologies well established in organic chemistry.     

A NOVEL APPROACH TO SOLID PHASE CHEMICAL SYNTHESIS OF OLIGONUCLEOTIDE mRNA CAP ANALOGS

A novel approach for the synthesis of 5′-capped 2′-O-methyloligoribonucleotides on a disulfide-tethered solid support is described. The key step of the synthesis is ZnCl₂ promoted coupling of m⁷GDP imidazolide to a fully deprotected oligonucleotide 5′-phosphate on-support. By this methodology m⁷G⁵′pppm²′Apm²′Upm^2′Ap has been prepared.     

Immobilization of amyloglucosidase from SSF of Aspergillus niger by crosslinked enzyme aggregate onto magnetic nanoparticles using minimum amount of carrier and characterizations

Immobilizations of enzymes are done for operational stability, recovery and re-use of the enzymes and easy separation of products. Amyloglucosidase (AMG) obtained from solid state fermentation (SSF) of Aspergillus niger was directly immobilized by novel technique of crosslinked enzyme aggregate onto magnetic nanoparticles. AMG was covalently linked to the magnetic nanoparticle (MNP) to form a monolayer of AMG (MNP–AMG), followed by crosslinked aggregates with free AMG (which was not immobilized) to yield MNP with high enzyme loading (MNP–AMG_n). Under optimized conditions, very high recovery (92.8%) of enzyme activity was obtained in MNP–AMG_n using 14 times less carrier compared to the quantity of carrier required by conventional method. MNP–AMG_n showed enhanced affinity for substrate, thermal stability, storage stability and reusability.     

Radiofrequency Catheter Ablation Of Atrioventricular Nodal Reentry Tachycardia In A Patient With Inferior Vena Cava Anomaly

Curative radiofrequency catheter modification of the slow pathway is the recommended therapy for patients suffering from recurrent symptomatic atrioventricular nodal reentry tachycardia. This is usually performed via femoral vein and the inferior vena cava (IVC). Presence of venous occlusion or complex venous anomaly involving the IVC may preclude this approach. Here, we report a case with a complex venous anomaly involving the inferior vena cava, who underwent electrophysiological study and successful radiofrequency ablation by an alternative approach.     

Electronic properties of some inorganic solids

A simple bonding model previously used to calculate cohesive energies is used to calculate electronic properties of simple solids. The model assumes that AB compounds of CN6 or 8 are completely ionic and that CN4 compounds, and metals, are completely covalent. It is then possible to calculate the electronic chemical potential, the work function and the average energy gap between filled and empty bands in insulators, semiconductors and conductors.     

Citric acid and polyols production by Aspergillus niger at high glucose concentration in solid state fermentation on inert support

Summary Aspergillus niger cultures at high initial glucose concentration (up to 400 g/1) on Amberlite as inert support were carried out. Citric acid was accumulated in the support showing high concentration (94.54 g/l) and productivity (1.35 g/l h) without inhibition related to the presence of metals (Mn²⁺, Zn²⁺, Co²⁺, Cu²⁺, and Ca²⁺) at high concentrations. Citric acid accumulation was clearly associated with both, glycerol production and to the age of the culture. Glycerol and erythritol, the major osmoregulator metabolites, were also produced (8.16 and 24.57 g/l respectively) at 400 g/l of glucose.     

Schistosoma mansoni: antigenic community between schistosomula surface and adult worm incubation products as a support for concomitant immunity

The use of protective monoclonal antibodies has enabled us to demonstrate antigenic community between a 38-kDa schistosomula surface molecule and a 115-kDa component derived from adult worms. Injection of adult worms in rats also led to the production of antibodies specific for the 38-kDa antigen, suggesting that the 115-kDa adult worm molecule could act as an inducer of the protective immune response raised against young invading parasites.