Photodegradation of 2-naphthol Using Nanocrystalline TiO2

The kinetics of the photocatalytic degradation of 2-naphthol has been investigated in aqueous suspensions of titanium dioxide (TiO2) under a variety of conditions, which is essential from application point of view. The degradation was studied using different parameters such as types of TiO2, catalyst concentration, substrate concentration, reaction pH and in the presence of different electron acceptors such as hydrogen peroxide (H2O2), potassium bromate (KBrO3) and potassium persulphate (K2S2O8) besides molecular oxygen. The degradation rates were found to be strongly influenced by all the above parameters. The photocatlyst ″Degussa P-25″ was found to be more efficient as compared with other photocatalysts. The results indicate the process follows Langmuir-Hinshelwood-type kinetics and inference is made of the reaction taking place on the semiconductor particle surface. An analysis of Total Organic Carbon (TOC) showed that a complete mineralization of 2-naphthol can be easily achieved.The kinetics of the photocatalytic degradation of 2-naphthol has been investigated in aqueous suspensions of titanium dioxide (TiO2) under a variety of conditions, which is essential from application point of view. The degradation was studied using different parameters such as types of TiO2, catalyst concentration, substrate concentration, reaction pH and in the presence of different electron acceptors such as hydrogen peroxide (H2O2), potassium bromate (KBrO3) and potassium persulphate (K2S2O8) besides molecular oxygen. The degradation rates were found to be strongly influenced by all the above parameters. The photocatlyst ″Degussa P-25″ was found to be more efficient as compared with other photocatalysts. The results indicate the process follows Langmuir-Hinshelwood-type kinetics and inference is made of the reaction taking place on the semiconductor particle surface. An analysis of Total Organic Carbon (TOC) showed that a complete mineralization of 2-naphthol can be easily achieved

Gene expression profiling of monkeypox virus-infected cells reveals novel interfaces for host-virus interactions

Monkeypox virus (MPV) is a zoonotic Orthopoxvirus and a potential biothreat agent that causes human disease with varying morbidity and mortality. Members of the Orthopoxvirus genus have been shown to suppress antiviral cell defenses, exploit host cell machinery, and delay infection-induced cell death. However, a comprehensive study of all host genes and virus-targeted host networks during infection is lacking. To better understand viral strategies adopted in manipulating routine host biology on global scale, we investigated the effect of MPV infection on Macaca mulatta kidney epithelial cells (MK2) using GeneChip rhesus macaque genome microarrays. Functional analysis of genes differentially expressed at 3 and 7 hours post infection showed distinctive regulation of canonical pathways and networks. While the majority of modulated histone-encoding genes exhibited sharp copy number increases, many of its transcription regulators were substantially suppressed; suggesting involvement of unknown viral factors in host histone expression. In agreement with known viral dependence on actin in motility, egress, and infection of adjacent cells, our results showed extensive regulation of genes usually involved in controlling actin expression dynamics. Similarly, a substantial ratio of genes contributing to cell cycle checkpoints exhibited concerted regulation that favors cell cycle progression in G1, S, G2 phases, but arrest cells in G2 phase and inhibits entry into mitosis. Moreover, the data showed that large number of infection-regulated genes is involved in molecular mechanisms characteristic of cancer canonical pathways. Interestingly, ten ion channels and transporters showed progressive suppression during the course of infection. Although the outcome of this unusual channel expression on cell osmotic homeostasis remains unknown, instability of cell osmotic balance and membrane potential has been implicated in intracellular pathogens egress. Our results highlight the role of histones, actin, cell cycle regulators, and ion channels in MPV infection, and propose these host functions as attractive research focal points in identifying novel drug intervention sites

Photominéralisation de l'uracile et des 5-halogeno-uraciles sur le dioxyde de titane. Effet du pH et de quelques anions sur la photodégradation de l'uracile

In oxygenated aqueous solutions, the photocatalytic degradation of uracil and its halogenated homologous is achieved on irradiated titanium dioxide. The kinetics of disappearance and mineralisation in carbon dioxide, ammonium, and nitrate ions are established. In presence of chloride, carbonate, sulphate and nitrate ions, photodisappearance of uracil is inhibited. This can be due to a partial blockage of catalyst active sites by these ions or their reaction with the oxidizing radicals such as HO$_3^0$ or OH$^0$. It is reported that, at pH lower than 6, disappearance kinetics of this pollutant is reduced

Improvement of the purification performance of the wastewater treatment plant (WWTP) of stabilization ponds type: Removal of sulfate and nitrate ions by adsorption onto micro ‐ particles of shrimp ‐ shells

The purpose of the this study carried out at the Tiznit wastewater treatment plant (WWTP) is to evaluate the purification performance of the conventional stabilization ponds type process and, on the other hand, to improve the purification performance by using adsorption process based on novel inert natural materials of animal origin. This project is part of a sustainable development approach, aimed to improve the purification performance of WWTP by introducing lowcost, abundant and inexpensive solid inert biomaterials (SIBM). This adsorption process is recognized as one of the best water treatment techniques, more and more works are oriented towards the search for new materials, cheaper and having a good adsorbent potential. The results obtained with decanted raw wastewater (RWWD) and purified wastewater (PWW) are encouraging and show significant purification yields: 52 % and 48 % for sulfate ions and 43 % and 47 % for nitrate ions, respectively, for RWWD and PWW

Preparation and caracterization of TiO2_{2} powder photocatalysts. Comparative studies of photocatalytic activity in the degradation of β\beta-naphthol

Titanium dioxide TiO$_{2}$ powder photocatalysts were prepared at the laboratory by two methods: hydrolysis of titanium tetraisopropoxide (TTIP) and the precipitation of a precursor starting from titanium tetrachloride TiCl$_{4}$ in basic medium. The products obtained are calcined at temperatures around 800$^{\circ}$C. Their characterization was carried out by both diffraction X-ray (XRD) and thermogravimetric analysis (TGA). The photocatalytic activity of the elaborate solids (TiO$_{2})$ is evaluated. It is compared with that given for commercial TiO$_{2}$ “Degussa P-25” in the degradation of $\beta$-naphthol chosen as an model molecule in aqueous suspension. These reactions are done at room temperature in a photochemical reactor

Methylated RASSF1a Is the First Specific DNA Marker for Minimal Residual Disease Testing in Neuroblastoma

Purpose: PCR-based detection of minimal residual disease (MRD) in neuroblastoma (NB) is presently based on NB-specific transcripts. However, the expression of these targets varies between patients and upon treatment, and only PHOX2B is truly specific. RASSF1a is methylated (RASSF1a(M)) in NB, and we investigated whether it can serve as a specific and stable DNA MRD marker. Patients and Methods: The RASSF1a(M)-specific quantitative real-time PCR was tested on control bone marrow (BM; n = 50), on 71 NB tumors, and on 159 clinical BM samples at diagnosis and at follow-up of 77 patients. Results were compared with a panel of RNA markers and correlated with prognosis. Results: RASSF1a(M) was present in all stage 4 and 4s tumors (n = 50) and in 86% stages 1 to 3 tumors (n = 21). The level of methylation in stage 4 NB was correlated with overall survival (P = 0.02). RASSF1a(M)-PCR was highly specific (only 1 amplification in 50 control samples tested in triplicate) and had a similar sensitivity as the RNA-based PCRs, as shown on clinical samples. Moreover, RASSF1a(M) enabled accurate quantification without need for the original tumor. Conclusions: RASSF1a(M) am is a novel, highly specific DNA marker for MRD detection in NB, equal to PHOX2B in specificity and sensitivity, and better suitable for MRD quantification. We propose to include RASSF1a(M) in further prospective MRD studies in NB alongside RNA MRD markers. In addition, this assay might also be applicable for detection of circulating tumor cells in patients with other cancers with RASSF1a(M) such as breast or lung cancer. Clin Cancer Res; 18(3); 808-14. (C)2011 AAC

Smallpox DNA Vaccine Protects Nonhuman Primates against Lethal Monkeypox

Two decades after a worldwide vaccination campaign was used to successfully eradicate naturally occurring smallpox, the threat of bioterrorism has led to renewed vaccination programs. In addition, sporadic outbreaks of human monkeypox in Africa and a recent outbreak of human monkeypox in the U.S. have made it clear that naturally occurring zoonotic orthopoxvirus diseases remain a public health concern. Much of the threat posed by orthopoxviruses could be eliminated by vaccination; however, because the smallpox vaccine is a live orthopoxvirus vaccine (vaccinia virus) administered to the skin, the vaccine itself can pose a serious health risk. Here, we demonstrate that rhesus macaques vaccinated with a DNA vaccine consisting of four vaccinia virus genes (L1R, A27L, A33R, and B5R) were protected from severe disease after an otherwise lethal challenge with monkeypox virus. Animals vaccinated with a single gene (L1R) which encodes a target of neutralizing antibodies developed severe disease but survived. This is the first demonstration that a subunit vaccine approach to smallpox-monkeypox immunization is feasible