Degradation of 17beta-estradiol and bisphenol A in aqueous medium by using ozone and ozone/UV techniques

Decomposition and complete degradation of two endocrine disrupters, namely 17beta-estradiol (E2) and bisphenol A (BPA) in aqueous medium by using ozone (O3) only and O3/UV advanced oxidation techniques (AOT) has been studied. The efficiency of the O3 systems used were determined based on the initial conversion and complete degradation of the substrates. Within the limits of the O3 dosages used, coupling of UV decreased the O3 consumption by 22.5% in converting the same amount of E2. Also the time to convert the same amount of E2 was considerably decreased. It was observed that there is no significant difference in O3 amount consumed for complete conversion of BPA by O3 and O3/UV systems. However, when O3 dosage decreased the amount of BPA conversion exhibits significant differences between two processes. The intermediate products formed during the oxidation of E2 were determined to be formed by oxidation of aromatic side of E2 with O3/*OH radical.     

A new mutation in the yeast aspartate kinase induces threonine accumulation in a temperature-regulated way

In Saccharomyces cerevisiae, aspartate kinase (the HOM3 product) regulates the metabolic flux through the threonine biosynthetic pathway through feedback inhibition by the end product. In order to obtain a strain able to produce threonine in a controlled way, we have isolated a mutant allele (HOM3-ts31d) that gives rise to a deregulated aspartate kinase. This allele has been isolated as an extragenic suppressor of ilv1, which confers an Ilv+ phenotype at 37 degrees C but not at 22 degrees C. We have stated that at high temperature the mutant aspartate kinase is slightly more deregulated and shows a higher specific activity, inducing threonine accumulation. The HOM3-ts31d allele carries a mutation that leads to a Ser399 --> Phe substitution in the postulated regulatory region of the enzyme. We have detected other changes in the nucleotide sequence but they are also present in the parental strain, reflecting the genetic differences between different wild-type strains. A sequence comparison among all the reported mutant aspartate kinases suggests that not all residues involved in regulation of the activity are clustered in the so-called regulatory domain, as is the case of that mutated in AK-R7, another deregulated aspartate kinase obtained with the same strategy of ilv1 suppression.     

Muscarinic receptors in rat cortex, hippocampus, hypothalamus and brainstem following transient forebrain ischemia and hemorrhagic shock

[3H]Quinuclidinyl benzilate binding properties of cerebral cortex, hippocampus, hypothalamus and brainstem of rats subjected to transient forebrain ischemia or severe hemorrhagic shock were investigated. Maximal binding capacities (Bmax) were not significantly different from control animals in either model. On the other hand, significant increases in binding affinities at all four brain regions in the ischemia-reperfusion group and at hypothalamic and brainstem membranes in the hemorrhagic shock group were observed. Kd values obtained in cortex and hippocampus of animals in shock were similar to control values. It was concluded that in brain ischemia models, the number of brain muscarinic receptors do not change at early stages, but binding affinities increase most likely due to systemic hypotension rather than reperfusion. The well-developed circle of Willis seems to protect cortical and hippocampal muscarinic receptors from hypoxia-induced changes.     

Purification and characterisation of a polyphenol oxidase from Boletus erythropus and investigation of its catalytic efficiency in selected organic solvents

Polyphenol oxidase (PPO) was purified from Boletus erythropus using a Sepharose 4B-L-tyrosine-p-amino benzoic acid affinity column. Optimum pH and temperature were found to be 8.0 and 20 °C, respectively, using 4-methylcatechol as a substrate. The enzyme was extremely stable between pH 3.0 and 9.0 after 24 h incubation at 4 °C. B. erythropus PPO was also quite stable between 10 and 30 °C after 4 h incubation. The K_m and V_max values were calculated as 2.8 mM and 1430 U/mg protein by Lineweaver–Burk curve, respectively. The enzyme activity was inhibited by sodium metabisulfite, ascorbic acid, sodium azide and benzoic acid. It was seen that the mushroom PPO was an effective biocatalyst in selected organic solvents, such as dichloromethane, dichloroethane and toluene, when catechin was used as a substrate. All data support that B. erythropus has a highly active PPO, possessing similar biochemical and kinetic characteristics to other plant PPOs.     

Impurity temperature correction factors for the transmission grating spectrometer in the TJ-II stellarator

Impurity ion temperature and velocity profiles are obtained across plasmas in the TJ-II stellarator by performing charge-exchange recombination spectroscopy with a diagnostic neutral beam injector. For this, a tridirectional (toroidal plus two poloidal opposing views) multichannel spectroscopic diagnostic, incorporating 12-way fiber arrays, a compact f/1.8 spectrograph, and a back-illuminated CCD, permits Doppler line shifts and widths (of the C VI line at 529.05 nm) to be determined with 1-2 cm spatial resolution. For good photon counting statistics under Li-coated wall conditions, 600?μm diameter fibers collect and transmit light to curved 100?μm wide input slits. When calibrated with a neon pencil lamp this entrance slit width results in a non-Gaussian instrumental function that, if not handled correctly, can result in systematically underestimated impurity temperatures. Here we develop and present correction factors for this effect for a range of conditions.     

Preparation and characterization of comb type polymer coated poly(HEMA/EGDMA) microspheres containing surface-anchored sulfonic acid: Application in γ-globulin separation

Poly(2-hydroxyethyl methacrylate/ethylenglycol dimethacrylate), poly(HEMA/EGDMA) microspheres was prepared via suspension polymerization. After activation of the hydroxyl groups of poly(HEMA/EGDMA) by bromination, surface-initiated atom transfer radical polymerization (ATRP) of glycidylmethacrylate was conducted in dioxane/bipyridine mixture with CuBr as catalyst at 65 °C. The epoxy groups of the poly(glycidylmethacrylate) comb polymer were converted into sulfonic acid groups (as proton-exchange groups) with reaction of sodium sulfite. Synthesized microspheres were characterized by swelling studies, FT-IR spectroscopy, scanning electron microscopy (SEM) and elemental analysis. The microspheres were used as ion-exchange support for adsorption and purification of human γ-globulin (IgG). The maximum γ-globulin adsorption on the ion-exchange adsorbents was observed at between pH 5.0 and 6.0. The IgG adsorption onto the poly(HEMA/EGDMA) microspheres was negligible. The maximum amount of adsorbed γ-globulin was found to be 230.1 mg/g microspheres. The ion-exchange adsorbents allowed one-step separation of IgG from human plasma. The γ-globulin molecules could be repeatedly adsorbed and desorbed with this ion-exchange support without noticeable loss in their IgG adsorption capacity.     

Preliminary characterization of an experimental breast cancer cells brain metastasis mouse model by MRI/MRS

PURPOSE: Chemotherapy increases survival in breast cancer patients. Consequently, cerebral metastases have recently become a significant clinical problem, with an incidence of 30-40% among breast carcinoma patients. As this phenomenon cannot be studied longitudinally in humans, models which mimic brain metastasis are needed to investigate its pathogenesis. Such models may later be used in experimental therapeutic approaches. MATERIAL AND METHODS/RESULTS: We report a model in which 69% of the animals (9/13 BALB/c nude mice) developed MR-detectable abnormal masses in the brain parenchyma within a 20 to 62-day time window post intra-carotid injection of 435-Br1 human cells. The masses detected in vivo were either single (7 animals) or multiple (2 animals). Longitudinal MR (MRI/MRS) studies and post-mortem histological data were correlated, revealing a total incidence of experimental brain metastases of 85% in the cases studied (11/13 animals). ADC maps perfectly differentiated edema and/or CSF areas from metastasis. Preliminary MRS data also revealed additional features: decrease in N-acetyl aspartate (NAA) was the first MRS-based marker of metastasis growth in the brain (micrometastasis); choline-containing compounds (Cho) rose and creatine (Cr) levels decreased as these lesions evolved, with mobile lipids and lactate also becoming visible. Furthermore, MRS pattern recognition-based analysis suggested that this approach may help to discriminate different growth stages. CONCLUSIONS: This study paves the way for further in vivo studies oriented towards detection of different tumor progression states and for improving treatment efficiency.     

Iodine-131: a potential short-lived, wastewater-specific particle tracer in an urbanized estuarine system

The short-lived, fission-produced radioisotope, 131I (t1/2 = 8.04 days), was detected in wastewater, surficial sediment, and suspended particulate matter (SPM) samples collected from New York Harbor (NYH) between 2001 and 2002. lodine-131 is used as a radiopharmaceutical for medical imaging, diagnostics, and treatments for conditions of the thyroid. It is introduced into the municipal waste stream by medical facilities and patients and is subsequently released into the estuary via wastewater effluent. Measured 131I activities in surface sediments were correlated with those of 7Be (t1/2 = 53.2 days), a naturally occurring radioisotope that is widely used to quantify particle dynamics, sediment focusing, and short-term sediment deposition and accumulation in aquatic systems. Surficial sediment 131I activities were also compared with measured trace metal (Cu, Pb) and organic carbon (OC(sed)) concentrations which can be linked to wastewater inputs. These preliminary results from NYH introduce 131I as a potentially valuable source-specific, shortlived biogeochemical tracer (timescales < 1 month) for particles, sediments, and wastewater-sourced contaminants in urbanized aquatic systems.     

Antioxidative activities of grape (Vitis vinifera) seed extracts obtained from different varieties grown in Turkey

In this study, total phenolic contents and antioxidant activities of grape seed extracts obtained from twelve different grape seeds from common varieties grown in Turkey were determined. Grape seeds were extracted with 70% acetone and extraction yield of grape seed were calculated. The total phenolic content of grape seed extracts were determined by the Folin‐Ciocalteu procedure and ranged from 33 945 to 58 730 mg per 100 g extract as gallic acid equivalent. Antioxidant activities of grape seed extracts with two different free radical scavenging methods, ABTS [2,2/‐azinobis (3‐ethylbenzothiazoneline‐6‐sulfonic acid)] and DPPH (2,2‐diphenyl‐picrylhydrazyl) assays, using Trolox equivalent as standards, were investigated. Grape seed extracts exhibited antioxidant activities 2.46–4.14 and 3.55–5.76 [Trolox equivalent antioxidant capacities (TEAC) mg^?1 extracts] in ABTS and DPPH assays, respectively. Compared with varieties, Muskule extracts exhibited the lowest total phenolic content, TEAC_ABTS and TEAC_DPPH value while Narince extracts had the highest total phenolic content and TEAC_DPPH value, and Alphonse Lavalleé had the highest TEAC_ABTS value. Total phenolic content showed that there is a significant correlation with TEAC_DPPH (r = 0.7974, P ≤ 0.001) and TEAC_ABTS values (r = 0.4860, P ≤ 0.05).