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Selected Abstracts3D Reconstruction of Real World Scenes Using a Low-Cost 3D Range ScannerCOMPUTER-AIDED CIVIL AND INFRASTRUCTURE ENGINEERING, Issue 7 2006Paulo Dias The article describes the mechanical and control issues addressed to physically achieve the 3D sensor used to acquire the data. It also presents the techniques used to process and merge range and intensity data to create textured polygonal models and illustrates the potential of such a unit. The result is a promising system for 3D modeling of real world scenes at a commercial price 10 or 20 times lower than current commercial 3D laser scanners. The use of such a system can simplify measurements of existing buildings and produce easily 3D models and ortophotos of existing structures with minimum effort and at an affordable price. [source] Induction of apoptosis by A3 adenosine receptor agonist N6 -(3-iodobenzyl)-adenosine-5,- N -methylcarboxamide in human leukaemia cells: a possible involvement of intracellular mechanismACTA PHYSIOLOGICA, Issue 2 2010P. Mlejnek Abstract Aim:, The sensitivity of cancer cells which exhibit multi-drug resistance phenotype to A3 adenosine receptor (A3AR) agonist N6 -(3-iodobenzyl)-adenosine-5,- N -methylcarboxamide (IB-MECA) was studied. Methods:, To establish direct relationship between P-glycoprotein (P-gp, ABCB1 and MDR1) expression and IB-MECA induced cell death, a straightforward method for precise estimation of intracellular level of this A3AR agonist was developed. Results:, We subjected three human leukaemia cell lines HL-60, K562 and K562/HHT to treatment with micromolar concentrations of IB-MECA. Although all cell lines used expressed A3AR, there was a large difference in their sensitivity to IB-MECA. While HL-60 and K562 cells were almost equally sensitive, the K562/HHT cells, which exhibit a multi-drug resistance phenotype because of overexpression of P-gp, were significantly more resistant. We found that the intracellular level of IB-MECA in K562/HHT cells was approx. 10 times lower than those in HL-60 or K562 cells. Inhibitors of P-gp, including cyclosporine A (CsA) and verapamil (Vpa), increased the intracellular level of IB-MECA and reversed the resistance of K562/HHT cells to this drug. Accordingly, shRNA-mediated down-regulation of P-gp significantly increased the intracellular level of IB-MECA in K562/HHT cells which simultaneously exhibited reduced resistance to this A3AR agonist. In addition, an in vitro enzyme-based assay provided evidence that IB-MECA might serve as a substrate for P-gp. Conclusion:, Our results suggest that P-gp overexpression prevents cells from IB-MECA induced apoptosis despite the A3AR expression. Pro-apoptotic effect of IB-MECA seemed to strongly depend on its intracellular accumulation rather than on its interaction with A3AR. [source] Low Recruitment of Trees Dispersed by Animals in African Forest FragmentsCONSERVATION BIOLOGY, Issue 6 2001N. J. Cordeiro We compared adult and juvenile trees in forest transects in a 3500,ha submontane forest with those in four forest fragments of 521, 30, 9, and 0.5 ha. Preliminary results show that recruitment of seedlings and juveniles of 31 animal-dispersed tree species was more than three times greater in continuous forest and large forest fragments (,30 ha) than in small forest fragments (,9 ha), whereas recruitment of eight wind- and gravity-dispersed trees of the forest interior was unaffected. Recruitment of 10 endemic, animal-dispersed tree species was 40 times lower in small fragments than in continuous forest or large fragments. Counts of diurnal primates and birds in all five sites indicated that frugivorous species have declined with decreasing fragment size. These results are consistent with the idea that loss of dispersal agents depresses tree recruitment in the course of forest fragmentation. Resumen: Investigamos los efectos de la fragmentación del bosque en la desaparición de animales frugívoros y el reclutamiento de árboles dispersados por animales y viento en parches de bosques de 80 años de edad en las montañas del este de Usambara, Tanzania. Comparamos árboles adultos y juveniles en transectos de bosque en un bosque submontañoso de 3500 ha con transectos de cuatro fragmentos de bosque de 521, 30, 9 y 0.5 ha. Los resultados preliminares muestran que el reclutamiento de plántulas y juveniles especies de árboles dispersados por animales fue tres veces mayor en el bosque continuo y fragmentos grandes (,30 ha) que en fragmentos pequeños (,9 ha), mientras que el reclutamiento de ocho árboles dispersados por viento y gravedad del interior del bosque no fue afectado. El reclutamiento de 10 especies endémicas de árboles dispersados por animales fue 40 veces menor en los fragmentos pequeños que en el bosque continuo o en los fragmentos grandes. Los conteos de primates diurnos y aves en los cinco sitios indican que las especies frugívoras han disminuido con la disminución del tamaño del fragmento. Estos resultados son consistentes con la idea de que la pérdida de los agentes dispersores deprime el reclutamiento de los árboles en el transcurso de la fragmentación del bosque. [source] The novel nootropic compound DM232 (UNIFIRAM) ameliorates memory impairment in mice and ratsDRUG DEVELOPMENT RESEARCH, Issue 1 2002Carla Ghelardini Abstract The favorable pharmacological profile exhibited by piracetam stimulated the synthesis of related compounds potentially endowed with a higher nootropic potency. The antiamnesic and procognitive activity of DM232 (unifiram), a new compound structurally related to piracetam, was investigated. Mouse passive avoidance and rat Morris water maze and Social learning tests were employed. DM232 (0.001,1 mg kg,1 i.p. , 0.01,0.1 1 mg kg,1 p.o.) prevented amnesia induced by scopolamine (1.5 mg kg,1 i.p.), mecamylamine (20 mg kg,1 i.p.), baclofen (2 mg kg,1 i.p.), and clonidine (0.125 mg kg,1 i.p.). Furthermore, The antiamnesic effect of the investigated compound was comparable to that exerted by well-known nootropic drugs such as piracetam (30,100 mg kg,1 i.p.), aniracetam (100 mg kg,1 p.o.), rolipram (30 mg kg,1 p.o.), and nicotine (5 mg kg,1 i.p). DM232 (0.1 mg kg,1 i.p.) was also able to prevent amnesia induced by scopolamine (0.8 mg kg,1 i.p.) in the rat Morris watermaze test. In the rat social learning test, DM232 (0.1 mg kg,1 i.p.) injected in adults rats reduced the duration of active exploration of the familiar partner in the second session of the test. DM232, similarly to piracetam, reduced the duration of hypnosis induced by pentobarbital. At the highest effective doses, the investigated compound did not impair motor coordination (rota rod test), nor modified spontaneous (Animex). These results indicate DM232 (unifiram) as a novel cognition enhancer, strictly related to piracetam-like compounds, able to ameliorate memory impairment at doses about 1,000 times lower than the most active available nootropic compounds. Drug Dev. Res. 56:23,32, 2002. © 2002 Wiley-Liss, Inc. [source] Separation of Nile Blue-labelled fatty acids by CE with absorbance detection using a red light-emitting diodeELECTROPHORESIS, Issue 8 2007Michael C. Breadmore Dr. Abstract The separation of fatty acids derivatised with Nile Blue (NB) by CE with detection using a red light-emitting diode (LED) was examined. NB was selected as the derivatisation agent due to its high molar absorption coefficient of 76,000,M,1cm,1 at 633,nm, making it well suited for sensitive absorbance detection using a red 635,nm LED. NB-labelled fatty acids were separated by both MEKC using SDS micelles, i -PrOH and n -BuOH and by NACE in a number of solvents including MeOH, EtOH and ACN. The sensitivity of NACE was superior to MEKC, with detection limits of 5×10,7,7×10,7,M obtained for each acid, approximately 20 times lower than the MEKC method. The NACE detection limits are approximately 100 times lower than previous reports on the separation of fatty acids by CE using indirect absorbance detection, ten times lower than using indirect fluorescence detection and are inferior only to those obtained using precapillary derivatisation and direct fluorescence detection. The efficiency of the NACE method was also superior to MEKC and allowed the separation of unsaturated fatty acids to be examined, although it was not possible to baseline-resolve linoleic (C18:2) and linolenic (C18:3) acids in a reasonable time. The method was used to analyse the fatty acid profile of two edible oils, namely sunflower and sesame oils, after alkali hydrolysis, where it was possible to identify both the saturated and unsaturated fatty acids in each sample. [source] Acute toxicity and bioaccumulation of pesticide Diazinon in red tilapia (Oreochromis niloticus x Mossambicus albina)ENVIRONMENTAL TOXICOLOGY, Issue 4 2002Jaime A. Palacio Abstract Young red tilapias were exposed for 96 h to each one of 6 concentrations of the pesticide Diazinon in order to determine the pesticide's acute toxicity level. After the ascertaining the lethal concentration (LC50) at 96 h, a level 10 times lower was selected for the bioaccumulation study of the pesticide in male and female specimens exposed for 9 days. The elimination process was carried out for 10 days beginning right after the conclusion of the accumulation process. Analytical procedures were developed and used for the studies of acute toxicity and bioaccumulation of Diazinon in red tilapia. A lethal concentration [LC50 (96 h)] of 3.85 mg/L was found, and steady-state accumulation, at a concentration of 28.45 mg/kg, was reached at 7.72 days. In the elimination process a concentration of 0.29 mg/kg was found in tilapia tissue by the sixth day after the fish were moved to clean water, and it continued to decrease quickly toward nondetectable levels. © 2002 Wiley Periodicals, Inc. Environ Toxicol 17: 334,340, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/tox.10063 [source] Bioavailability of decabromodiphenyl ether to the marine polychaete Nereis virensENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 4 2010Susan L. Klosterhaus Abstract The flame retardant decabromodiphenyl ether (BDE 209) accumulates in humans and terrestrial food webs, but few studies have reported the accumulation of BDE 209 in aquatic biota. To investigate the mechanisms controlling the bioavailability of BDE 209, a 28-d bioaccumulation experiment was conducted in which the marine polychaete worm Nereis virens was exposed to a decabromodiphenyl ether (deca-BDE) commercial mixture (>85% BDE 209) in spiked sediments, in spiked food, or in field sediments. Bioaccumulation from spiked substrate with maximum bioavailability demonstrated that BDE 209 accumulates in this species. Bioavailability depends on the exposure conditions, however, because BDE 209 in field sediments did not accumulate (<0.3 ng/g wet weight; 28-d biota-sediment accumulation factors [BSAFs] <0.001). When exposed to deca-BDE in spiked sediments also containing lower brominated congeners (a penta-BDE mixture), bioaccumulation of BDE 209 was 30 times lower than when exposed to deca-BDE alone. Selective accumulation of the lower brominated congeners supports their prevalence in higher trophic level species. The mechanisms responsible for limited accumulation of BDE 209 may involve characteristics of the sediment matrix and low transfer efficiency in the digestive fluid. Environ. Toxicol. Chem. 2010;29:860,868. © 2009 SETAC [source] Metallothionein gene expression and protein levels in triploid and diploid oysters Crassostrea gigas after exposure to cadmium and zincENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 2 2006Véronique Marie Abstract Quantitative real-time polymerase chain reaction (PCR) was used to compare for the first time the differential expression of metallothionein (MT) isoform genes, together with biosynthesis of the total MT proteins, in the gills of triploid and diploid juvenile Pacific oyster Crassostrea gigas in response to cadmium (Cd) and zinc (Zn) exposure. Oysters were exposed to Cd (0.133 ,M), Zn (15.3 ,M), and Cd+Zn for 14 d. Results showed similar response capacities to metal exposures in the two populations. No significant difference was revealed in terms of MT gene expression, MT protein synthesis, and Cd accumulation. However, triploid oysters bioaccumulated Zn 30% less efficiently than diploid oysters. Among the three MT isoform genes, CgMT2 appeared to be more expressed than CgMT1, whereas CgMT3 appeared to be anecdotal (106 times lower than CgMT2). CgMT2 and CgMT1 gene expression levels were increased sevenfold in the presence of Cd, whereas Zn appeared to have no effect. A twofold increase in MT protein levels occurred in response to Cd exposure. Discrepancies between mRNA and protein levels suggest that in C. gigas MT are regulated at the transcriptional level, as well as at the translational level. [source] Use of laboratory toxicity tests with bivalve and echinoderm embryos to evaluate the bioavailability of copper in San Diego Bay, California, USAENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 2 2005Gunther Rosen Abstract Copper concentrations in parts of San Diego Bay (CA, USA) exceed ambient water quality criteria (WQC; currently 3.1 ,g/L dissolved, U.S. Environmental Protection Agency [U.S. EPA]). In order to better understand the bioavailability of copper to water-column organisms in the bay, toxicity tests were performed with copper added to surface water collected from various sites in the estuary over a three-year period. The species and endpoints used, bivalve and echinoderm embryo-larval development, are among the most sensitive in the U.S. EPA's national toxicity dataset, which is used to derive WQC. No toxicity was observed in ambient bay water samples, as indicated by high proportions of normally developed larvae in control treatments, averaging 93 ± 5% across all sites and all sampling events. Median effects concentrations (EC50), obtained by copper spiking of ambient water samples, ranged from 1.7 to 3.4 times lower at sites located near the mouth compared to sites near the back of the bay. These data indicate a gradient in complexation capacity increasing from the mouth to the back of the bay, which is consistent with similar trends in dissolved organic carbon and total suspended solids. For the bay as a whole, estimates for total recoverable and dissolved water-effect ratios (WER) ranged from 2.07 to 2.27 and 1.54 to 1.67, respectively. Water-effect ratios of this magnitude suggest that adoption of a somewhat higher site-specific WQC for San Diego Bay still would achieve the level of protection that is intended by the WQC guidelines. [source] Comparing the solid phase and saline extract Microtox® assays for two polycyclic aromatic hydrocarbon-contaminated soilsENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 2 2004Carolyn M. Acheson Abstract The performance of remedial teatments is typically evaluated by measuring the concentration of specific chemicals. By adding toxicity bioassays to treatment evaluations, a fuller understanding of treatment performance is obtained. The solid phase Microtox® assay is a useful tool in characterizing the toxicity of contaminated soils and sediments. This study compares the performance of the solid phase and saline extract Microtox assays in two experiments using two soils contaminated with polycyclic aromatic hydrocarbons (PAHs). The first experiment, conducted to refine the solid phase assay procedures, evaluated sample holding times, sample replication, and reference toxicant controls. The effective concentration reducing light emission by 50% (EC50) of four samples was measured with eight replicates of each sample. Samples were stored for as long as two weeks without showing substantial changes in toxicity. For future studies, three replicates of each sample are recommended because that degree of replication yielded a statistical power of more than 95% in most samples. Phenol was a reliable reference toxicant with a mean EC50 of 21.76 and a 95% confidence interval of 15.6 to 27.9 mg/L. In a second experiment, the solid phase Microtox assay was compared to saline extract Microtox assays with mixing times ranging from 5 min to 16 h. The solid phase assay was more sensitive yielding EC50s 7 to 50 times lower than the extract EC50s. In addition, the saline extract assays displayed results that varied for mixing times of less than 2 h. Based on these two experiments, the solid phase Microtox test has proved to be a useful assay for measuring the toxicity of PAH-contaminated soils. [source] Toxicity of lead in aqueous medium to Desulfovibrio desulfuricans G20ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 2 2003Rajesh K. Sani Abstract The toxicity of Pb(II) to sulfate-reducing bacteria (SRB) was studied using Desulfovibrio desulfuricans G20 in a medium specifically designed to assess metal toxicity. The effects of Pb(II) toxicity were observed in terms of longer lag times, lower specific growth rates, and in some cases no measurable growth. With an increase in medium pH from 6 to 8, Pb(II) toxicity decreased. At all pH values, in the presence of Pb(II) concentrations ranging from 3 to 15 ,M, specific growth rates decreased and lag times increased. The minimum inhibiting concentration (MIC) of Pb(II) causing a complete inhibition in growth at pH 6 was 10 ,M, as compared to 15 ,M at pH 7.2 and 8. These MIC values are 40 times lower than previously reported for SRB. Results also show that with increases in initial cell protein concentration (inoculum size), soluble Pb(II) removal rates increased and the degree to which Pb(II) caused increased lag times was reduced. In the presence of Pb(II), in all cases in which D. desulfuricans grew (even after a 312-h lag time), the final cell protein concentration was equivalent to that of the Pb-free control. Live/dead staining, based on membrane integrity, indicated that while Pb(II) inhibited growth, Pb(II) did not cause a loss of D. desulfuricans membrane integrity. [source] Use of freshwater rotifer Brachionus calyciflorus in screening assay for potential endocrine disruptorsENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 12 2000Benjamin L. Preston Abstract eports of the effectsofendocrinedisruptorsonaquatic invertebrates arebecoming increasingly common. However, little is known about the endocrine systems of most aquatic invertebrates, limiting the development of assays based on endocrine mechanisms. As a result, endocrine disruption is often inferred through the effects caused by the chemical of interest, making it difficult to rule out other mechanisms of toxicity. To be a good candidate for an endocrine disruptor, effects should be observed in processes known to be under endocrine control, at life stages where endocrine signals are known to be active, and at concentrations below acute and chronic toxic effects. We developed a 96-h reproductive assay using the freshwater rotifer Brachionus calyciflorus to screen for potential endocrine disruptors and examined cadmium, chlorpyrifos, naphthol, pentachlorophenol, estradiol, methoprene, precocene, nonylphenol, flutamide, and testosterone for effects on asexual and sexual reproduction. Flutamide, testosterone, and nonylphenol inhibited fertilization of sexual females at concentrations of 1, 10, and 50 ,g/L, respectively. The fertilization no-observable-effect concentrations (NOECs) for these compounds were 5 to 200 times lower than previously described reproduction NOECs for B. calyciflorus. Sexual reproduction was inhibited with no effects on asexual reproduction, increasing the likelihood that these specific reproductive effects occurred through an endocrine mechanism. Rotifer reproduction assays may be a useful, rapid, and inexpensive method for screening compounds suspected to have endocrine disrupting activity in aquatic invertebrates. [source] A test of the community conditioning hypothesis: Persistence of effects in model ecological structures dosed with the jet fuel jp-8ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 2 2000Wayne G. Landis Abstract The foundation of the community conditioning hypothesis, the persistence of effects, was tested in a series of microcosm experiments. Experiments were conducted with the water-soluble fraction of the turbine fuel JP-8 using the standard protocols for the standardized aquatic microcosm (SAM). A repeat trial was conducted using the SAM protocol but with a 126-d test period, twice the standard duration. The results were examined using a variety of conventional univariate, multivariate, and graphical techniques. The principal conclusions were as follows. Effects are persistent in these model ecological systems long after the degradation of the toxicant. Patterns of impacts are detectable at concentrations 15 times lower than an experimentally derived single-species EC50. The replicate experiments are not replicable in the specific, but the broad pattern of the disruption of algal- herbivore dynamics followed by more subtle effects are consistently repeated. The durability of the indirect effects and therefore the information about historical events appears to be a consistent feature of these microcosm systems. The identity of the treatment groups persists. The critical features of the community conditioning hypothesis,persistence of information within ecologicalsystems and the reappearance of patterns and therefore the nonequilibrium dynamics,are again confirmed. The implications of these findings for environmental toxicology, monitoring, and ecological risk assessment are discussed. [source] Altered fatty acid pattern of phospholipids and triglycerides in the submandibular gland of ,3-depleted ratsEUROPEAN JOURNAL OF ORAL SCIENCES, Issue 2 2007Christine Delporte Alteration of the phospholipid (PL) and triglyceride (TG) fatty acid pattern was recently documented in several organs of rats depleted in long-chain polyunsaturated ,3 fatty acid (,3 rats). This study extends such a knowledge to the submandibular gland. The total PL and TG content of the salivary gland was not different in control and ,3 rats. The sole ,3 fatty acids found in ,3 rats (C22:5,3 and C22:6,3) were present at levels 3,12 times lower than in control rats. The C22:5,3/C22:6,3 ratio was increased threefold in ,3 rats. The PL and TG C16:0/C16:1,7 and C18:0/C18:1,9 ratios were decreased in ,3 rats. The conversion of C18:2,6 to C20:4,6 and C22:4,6 appeared facilitated in the ,3 rats. Some of these rats were injected intravenously, 60,120 min before killing, with either a medium-chain triglyceride:fish oil emulsion or a control medium-chain triglyceride:olive oil emulsion. The former emulsion increased the PL C22:5,3 and C22:6,3 content and prevented the age-related decrease in C16:0/C16:1,7 and C18:0/C18:1,9 ratios otherwise also recorded in PL. In conclusion, these findings document an increased activity of ,9-desaturase, a more efficient conversion of C18:2,6 to its metabolites, and an impaired generation of C22:6,3 from C22:5,3 in ,3 rats. [source] Photoregulation of DNA transcription by using photoresponsive T7 promoters and clarification of its mechanismFEBS JOURNAL, Issue 6 2010Xingguo Liang With the use of photoresponsive T7 promoters tethering two 2,-methylazobenzenes or 2,,6,-dimethylazobenzenes, highly efficient photoregulation of DNA transcription was obtained. After UV-A light irradiation (320,400 nm), the rate of transcription with T7 RNA polymerase and a photoresponsive promoter involving two 2,,6,-dimethylazobenzenes was 10-fold faster than that after visible light irradiation (400,600 nm). By attaching a nonmodified azobenzene and 2,,6,-dimethylazobenzene at the two positions, respectively, and by utilizing the different cis,trans thermal stability between cis -nonmodified azobenzene and cis- 2,,6,-dimethylazobenzene, four species of T7 promoter (cis,cis, trans,cis, cis,trans, and trans,trans) were obtained. The four species showed transcriptional activity in the order of cis,cis > cis,trans > trans,cis > trans,trans. Kinetic analysis revealed that the Km for the cis,cis promoter (both of the introduced azobenzene derivatives were in the cis form) and T7 RNA polymerase was 68 times lower than that for the trans,trans form, indicating that high photoregulatory efficiency was mainly due to a remarkable difference in affinity for RNA polymerase. The present approach is promising for the creation of biological tools for artificially controlling gene expression, and as a photocontrolled system for supplying RNA fuel for RNA-powered molecular nanomachines. [source] Protists with different feeding modes change biofilm morphologyFEMS MICROBIOLOGY ECOLOGY, Issue 2 2009Anne Böhme Abstract The effect of Dexiostoma (filter feeder), Vannella, Chilodonella (raptorial feeders), Spumella, and Neobodo (direct interception feeders) on the morphology of multispecies bacterial biofilms was investigated in small flow cells. The filter feeder Dexiostoma campylum did not alter biofilm volume and porosity but stimulated the formation of larger microcolonies compared with ungrazed biofilms. In contrast, the raptorial feeder Vannella sp. efficiently grazed bacteria from the biofilm surface, leading to smaller microcolonies and lower maximal and basal layer thickness compared with ungrazed biofilms. Microcolony formation was not stimulated in the presence of the sessile Spumella sp. Chilodonella uncinata rasped bacteria from the outer surface leading to mushroom-shaped microcolonies. In the presence of C. uncinata and Spumella sp., the biofilm volume was 2.5,6.3 times lower compared with ungrazed biofilms. However, the biofilm porosity and the ratio of biofilm surface area to biofilm volume were 1.5,3.7 and 1.2,1.8 times higher, respectively. Thus, exchange of nutrients and gases between the biofilm and its surrounding fluid should also be improved in deeper biofilm layers, hence accelerating microbial growth. [source] The response of the yeast Saccharomyces cerevisiae to sudden vs. gradual changes in environmental stress monitored by expression of the stress response protein Hsp12pFEMS YEAST RESEARCH, Issue 6 2008Ildar Nisamedtinov Abstract The response of the yeast Saccharomyces cerevisiae to sudden vs. gradual changes in different environmental stress conditions during both respiratory growth and aerobic fermentative growth in the presence of excess glucose was investigated by monitoring the level and rate of expression of the stress response protein Hsp12p using the fluorescent fusion construct Hsp12p-Gfp2p. The initial expression level and the rate of Hsp12p synthesis was significantly greater under glucose-limited conditions in the chemostat (D<0.14 h,1) compared with when excess glucose was present in the auxostat. Decreasing the dilution rate and the glucose concentration further in the A-stat resulted in increased Hsp12p expression, which was more marked when a rapid rather than a gradual change was affected. Common stress factors such as NaCl, ethanol and elevated temperature caused stress responses in both D-stat and auxo-accelerostat culture. The magnitude of the stress response depended on the stress factor, cultivation conditions as well as the rate of change of the stress factor. The rate of Hsp12p synthesis increased due to all applied stresses, with the observed increase between 2 and 20 times lower when the stress was applied gradually rather than rapidly. The results suggested that the Hsp12p expression rate is a good indicator of applied stress in S. cerevisiae. [source] Gold-Nanocluster-Based Fluorescent Sensors for Highly Sensitive and Selective Detection of Cyanide in WaterADVANCED FUNCTIONAL MATERIALS, Issue 6 2010Yanlan Liu Abstract A novel, gold-nanocluster-based fluorescent sensor for cyanide in aqueous solution, which is based on the cyanide etching-induced fluorescence quenching of gold nanoclusters, is reported. In addition to offering high selectivity due to the unique Elsner reaction between cyanide and the gold atoms of gold nanoclusters, this facile, environmentally friendly and cost-effective method provides high sensitivity. With this sensor, the lowest concentration to quantify cyanide ions could be down to 200,×,10,9,M, which is approximately 14 times lower than the maximum level (2.7,×,10,6,M) of cyanide in drinking water permitted by the World Health Organization (WHO). Furthermore, several real water samples spiked with cyanide, including local groundwater, tap water, pond water, and lake water, are analyzed using the sensing system, and experimental results show that this fluorescent sensor exhibits excellent recoveries (over 93%). This gold-nanocluster-based fluorescent sensor could find applications in highly sensitive and selective detection of cyanide in food, soil, water, and biological samples. [source] Synthetic Strategies for Hybrid Materials to Improve Properties for Optoelectronic Applications,ADVANCED FUNCTIONAL MATERIALS, Issue 14 2008Olga García Abstract We report, for the first time to the best of our knowledge, a systematic study to relate the laser action from BODIPY dyes, doped into monolithic hybrid matrices, with the synthetic protocols of the final materials prepared via sol-gel. To this aim, the influence of both the hydrolysis time, increased in a controlled way, and the nature of the neutralization agent (pyridine, 3-amino-propyltriethoxy-silane (APS), N -[3-(trimethoxysilyl)propyl]-ethylene diamine (TSPDA), and N1 -[3-(trimethoxysilyl)propyl]- diethylene triamine (TSPTA) on the laser action of PM567, incorporated into hybrid matrices based on copolymers of methyl methacrylate (MMA) and 2-hydroxyethyl methacrylate (HEMA), with methyltriethoxysilane (TRIEOS) as inorganic precursor, was analyzed. The presence of the amine-modified silane TSPDA as neutralization agent, which is able at the same time to be anchored to the inorganic network enhancing the inorganic-organic compatibility through the matrix interphase, and utilization of hydrolysis times lower than 10 minutes, increased significantly the lasing efficiency and photostability of dye. The extension of this study to the laser behavior of BODIPY dyes embedded in other different hybrid materials based on hydrolyzed-condensed copolymers of MMA with 3-(trimethoxysilyl)propyl methacrylate (TMSPMA) in a 1/1 volumetric proportion, validates the generalization of the above conclusions, which provide guides for the optimization of the synthesis of organic-inorganic hybrid materials with optoelectronic innovative applications independently of their composition. [source] Assessing the impact of the hydraulic properties of a crusted soil on overland flow modelling at the field scaleHYDROLOGICAL PROCESSES, Issue 8 2006Nanée Chahinian Abstract Soil surface crusts are widely reported to favour Hortonian runoff, but are not explicitly represented in most rainfall-runoff models. The aim of this paper is to assess the impact of soil surface crusts on infiltration and runoff modelling at two spatial scales, i.e. the local scale and the plot scale. At the local scale, two separate single ring infiltration experiments are undertaken. The first is performed on the undisturbed soil, whereas the second is done after removal of the soil surface crust. The HYDRUS 2D two-dimensional vertical infiltration model is then used in an inverse modelling approach, first to estimate the soil hydraulic properties of the crust and the subsoil, and then the effective hydraulic properties of the soil represented as a single uniform layer. The results show that the crust hydraulic conductivity is 10 times lower than that of the subsoil, thus illustrating the limiting role the crust has on infiltration. Moving up to the plot scale, a rainfall-runoff model coupling the Richards equation to a transfer function is used to simulate Hortonian overland flow hydrographs. The previously calculated hydraulic properties are used, and a comparison is undertaken between a single-layer and a double-layer representation of the crusted soil. The results of the rainfall-runoff model show that the soil hydraulic properties calculated at the local scale give acceptable results when used to model runoff at the plot scale directly, without any numerical calibration. Also, at the plot scale, no clear improvement of the results can be seen when using a double-layer representation of the soil in comparison with a single homogeneous layer. This is due to the hydrological characteristics of Hortonian runoff, which is triggered by a rainfall intensity exceeding the saturated hydraulic conductivity of the soil surface. Consequently, the rainfall-runoff model is more sensitive to rainfall than to the subsoil's hydrodynamic properties. Therefore, the use of a double-layer soil model to represent runoff on a crusted soil does not seem necessary, as the increase of precision in the soil discretization is not justified by a better performance of the model. Copyright © 2005 John Wiley & Sons, Ltd. [source] pH-controlled cell release and biomass distribution of alginate-immobilized Lactococcus lactis subsp. lactisJOURNAL OF APPLIED MICROBIOLOGY, Issue 4 2001G. Klinkenberg Aims:,To investigate the growth and release of Lactococcus lactis subsp. lactis in gel beads and to affect rates of cell release by changing the growth conditions. Methods and Results:,The rate of release and the distribution of immobilized L. lactis subsp. lactis in alginate beads were studied in continuous fermentations for 48 h. A change in operating pH from 6·5 to 9·25 initially reduced the ratio of the rates of cell release to lactate production by almost a factor of 105. Compared with fermentations at pH 6·5, growth at pH 9·25 also increased the final internal bead biomass concentration by a factor of 5 and increased the final rate of lactate production by 25%. After 48 h, the ratio of the rates of cell release to lactate production was still 10 times lower than in fermentations at pH 6·5. Conclusions:,A change in the operating pH from 6·5 to 9·25 reduced rates of cell release throughout 48 h of fermentation and increased the final rates of lactate production and internal bead biomass concentration. Significance and Impact of the Study:,These data illustrate that diffusional limitations and corresponding pH gradients can be exploited in affecting the distribution of immobilized growing cells and their concomitant release. [source] Effect of weak reductant on properties of electroless copper polyacrylonitrile nanocomposites for electromagnetic interference shieldingJOURNAL OF APPLIED POLYMER SCIENCE, Issue 2 2010Keng-Yu Tsao Abstract In this work, the electroless copper method with different reductant compositions (NaHSO3/Na2 S2O3·5H2O and Na2S2O3·5H2O) without sensitizing and activating, was used to deposit copper-sulfide deposition on the polyacrylonitrile (PAN) surface for electromagnetic interference (EMI) shielding materials. The weak reductant, NaHSO3, in the electroless copper method was used to control the phase of copper-sulfide deposition. The Cux(x=1,1.8)S was deposited on the PAN (CuxS-PAN) by reductant composition (NaHSO3/Na2S2O3·5H2O) and the Cux(x=1,1.8)S deposition of CuxS-PAN possesses three kinds of copper-sulfide phases (CuS, Cu1.75S and Cu1.8S). However, the electroless copper with reductant was only Na2S2O3·5H2O (without weak reductant, NaHSO3), the hexagonal CuS deposition was plated on the PAN (CuS-PAN) and increased the EMI shielding effectiveness of CuS-PAN composites about 10,15 dB. In this study, the best EMI SE of CuS-PAN and CuxS-PAN composites were about 27,30 dB and 15,17 dB respectively, as the cupric ion concentration was 0.24 M. The volume resistivity of CuS-PAN composite was about 1000 times lower than that of CuxS-PAN composite and lowest volume resistivity of CuS-PAN composites was 0.012 , cm, as the cupric ion concentration was 0.24 M. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 [source] Biochemical and ultrastructural alterations in the rat ventral prostate due to repetitive alcohol drinkingJOURNAL OF APPLIED TOXICOLOGY, Issue 4 2007M. I. Díaz Gómez Abstract Previous studies showed that cytosolic and microsomal fractions from rat ventral prostate are able to biotransform ethanol to acetaldehyde and 1-hydroxyethyl radicals via xanthine oxidase and a non P450 dependent pathway respectively. Sprague Dawley male rats were fed with a Lieber and De Carli diet containing ethanol for 28 days and compared against adequately pair-fed controls. Prostate microsomal fractions were found to exhibit CYP2E1-mediated hydroxylase activity significantly lower than in the liver and it was induced by repetitive ethanol drinking. Ethanol drinking led to an increased susceptibility of prostatic lipids to oxidation, as detected by t-butylhydroperoxide-promoted chemiluminiscence emission and increased levels of lipid hydroperoxides (xylenol orange method). Ultrastructural alterations in the epithelial cells were observed. They consisted of marked condensation of chromatin around the perinuclear membrane, moderate dilatation of the endoplasmic reticulum and an increased number of epithelial cells undergoing apoptosis. The prostatic alcohol dehydrogenase activity of the stock rats was 4.84 times lower than that in the liver and aldehyde dehydrogenase activity in their microsomal, cytosolic and mitochondrial fractions was either not detectable or significantly less intense than in the liver. A single dose of ethanol led to significant acetaldehyde accumulation in the prostate. The results suggest that acetaldehyde accumulation in prostate tissue might result from both acetaldehyde produced in situ but also because of its low aldehyde dehydrogenase activity and its poor ability to metabolize acetaldehyde arriving via the blood. Acetaldehyde, 1-hydroxyethyl radical and the oxidative stress produced may lead to epithelial cell injury. Copyright © 2007 John Wiley & Sons, Ltd. [source] Naringin, a grapefruit flavanone, protects V79 cells against the bleomycin-induced genotoxicity and decline in survivalJOURNAL OF APPLIED TOXICOLOGY, Issue 2 2007Abhinav Jagetia Abstract The effect of naringin, a grapefruit flavonone was studied on bleomycin-induced genomic damage and alteration in the survival of cultured V79 cells. Exposure of V79 cells to bleomycin induced a concentration dependent elevation in the frequency of binucleate cells bearing micronuclei (MNBNC) and a maximum number of MNBNCs were observed in the cells treated with 50 ,g ml,1 bleomycin, the highest concentration evaluated. This genotoxic effect of bleomycin was reflected in the cell survival, where a concentration dependent decline was observed in the cells treated with different concentrations of bleomycin. Treatment of cells with 1 mm naringin before exposure to different concentrations of bleomycin arrested the bleomycin-induced decline in the cell survival accompanied by a significant reduction in the frequency of micronuclei when compared with bleomycin treatment alone. The cell survival and micronuclei induction were found to be inversely correlated. The repair kinetics of DNA damage induced by bleomycin was evaluated by exposing the cells to 10 ,g ml,1 bleomycin using single cell gel electrophoresis. Treatment of V79 cells with bleomycin resulted in a continuous increase in DNA damage up to 6 h post-bleomycin treatment as evident by migration of more DNA into the tails (% tail DNA) of the comets and a subsequent increase in olive tail moment (OTM), an index of DNA damage. Treatment of V79 cells with 1 mm naringin reduced bleomycin-induced DNA damage and accelerated DNA repair as indicated by a reduction in % tail DNA and OTM with increasing assessment time. A maximum reduction in the DNA damage was observed at 6 h post-bleomycin treatment, where it was 5 times lower than bleomycin alone. Our study, which was conducted on the basis of antioxidant, free radical scavenging and metal chelating properties of naringin demonstrates that naringin reduced the genotoxic effects of bleomycin and consequently increased the cell survival and therefore may act as a chemoprotective agent in clinical situations. Copyright © 2006 John Wiley & Sons, Ltd. [source] Effect of loading rate on TOC consumption efficiency in a sulfate reducing process: sulfide effect in batch cultureJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 12 2008Citlali García-Saucedo Abstract BACKGROUND: The sulfate reducing process (SRP) was analyzed in order to identify factors that diminish the effectiveness of the SRP during wastewater treatment. The effect of different sulfate loading rates (SLR, 290 to 981 mg SO4 -S L,1d,1) and lactate at a stoichiometric C/S ratio of 0.75 on SRP was studied in an upflow anaerobic sludge blanket (UASB) reactor. The effect of sulfide concentration (0 to 200 mg sulfide-S L,1) on SRP in batch culture was evaluated. RESULTS: When the SLR was increased, the total organic carbon (TOC) and sulfate consumption efficiencies decreased from 93% ± 3 to 66% ± 2 and 60% ± 5 to 45% ± 4, respectively. Acetate and propionate were accumulated. Microbial analysis showed the presence of microorganisms related with the SRP, fermentation and methanogenesis. In batch culture, when lactate and sulfate were present, SRP and fermentation were observed. When sulfide was added only SRP was observed. At concentrations higher than 150 mg sulfide-S L,1 the efficiencies, yields and specific consumption rates (q) decreased. CONCLUSION: Based on the sulfide-S/volatile suspended solid ratio, it was found that the decrease in efficiency and accumulation of acetate and propionate in the UASB reactor was not related to sulfide inhibition but to the q of acetate and propionate, which were up to 11 times lower than lactate. Copyright © 2008 Society of Chemical Industry [source] Importance of the olfactory sense to migratory sea lampreys Petromyzon marinus seeking riverine spawning habitatJOURNAL OF FISH BIOLOGY, Issue 4 2010L. A. Vrieze This study tested the hypothesis that the sea lamprey Petromyzon marinus, a diadromous species of fish, relies on innately discerned odours, including pheromones, to locate riverine spawning habitat. Migratory, sexually immature P. marinus were captured as they entered streams flowing into the Great Lakes, and their olfactory systems were occluded or not by injecting either innocuous dental impression material or a saline control into their nasopores. Animals were then released back into lakes or streams and their recapture rates in stream traps noted. When released into Lake Huron, P. marinus with intact (functional) olfactory systems were very successful in locating rivers (recapture rates ranged up to 65%), while animals with occluded nasopores were virtually unable to do so and had recapture rates five to 20 times lower than intact animals. With few exceptions, intact fish entered the stream closest to their release point within a few days, irrespective of where they had been originally captured; their ability to locate streams is apparently innate and well developed. In contrast, when released within streams, both intact and occluded P. marinus successfully swam upstream to traps for several days although the ability of the former exceeded that of the latter after this period. Migratory P. marinus rely heavily on olfactory cues, of which a larval pheromone is presumably one, to locate river mouths and to a lesser extent to promote upstream movement within rivers. [source] Resistance Variation of Salmonella enterica Serovars to Pulsed Electric Fields TreatmentsJOURNAL OF FOOD SCIENCE, Issue 7 2003I. ÁLvarez ABSTRACT: Inactivation of Salmonella serovar Enteritidis and Salmonella serovar Typhimurium by pulsed electric fields has been investigated. A tertiary model based on the Weibull distribution (n= 0.262) and on a new parameter (ZPEF), accurately described the kinetics of inactivation of these microorganisms among 15 and 28 kV/cm. In the range of 19 to 28 kV/cm, this model also described previously published data of inactivation of serovar Senftenberg when the n value was set at 0.437. The ZPEF value for the 3 Salmonella serovars was 15.787 kV/cm. From 19 to 28 kV/cm, the time to inactivate 5 Log10 cycles of the population of serovar Enteritidis was 2.06 and 2.66 times lower than that to inactivate serovar Typhimurium and serovar Senftenberg, respectively. [source] Relative in vitro efficacy of the phosphate binders lanthanum carbonate and sevelamer hydrochlorideJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 10 2007Valerie Autissier Abstract The high tablet burden and poor compliance associated with phosphate-binding drugs has led to a search for more potent agents. In vitro -binding studies were performed on the recently introduced binder, lanthanum carbonate (LC; Fosrenol®), to compare its phosphate-binding affinity with sevelamer hydrochloride (SH; RenagelÔ). Langmuir equilibrium binding affinities (K1) for LC and SH were established using different phosphorus (5,100 mM) and binder (134,670 mg per 50 mL) concentrations at pH 3,7, with or without salts of bile acids present (30 mM). At all pH levels, LC had a higher binding affinity for phosphate than SH. For LC, K1 was 6.1,±,1.0 mM,1 and was independent of pH. For SH, K1 was pH dependent, being 1.5,±,0.8 mM,1 at pH 5,7 and 0.025,±,0.002 mM,1 at pH 3, that is, >200 times lower than for LC. In the presence of 30 mM bile salts, SH lost 50% of its phosphate, whereas no displacement of phosphate occurred for LC. These findings indicate that LC binds phosphate more effectively than SH across the pH range encountered in the gastrointestinal tract, and has a lower propensity for bound phosphate to be displaced by competing anions in the intestine. © 2007 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 96: 2818,2827, 2007 [source] Fluorescence background suppression in Raman spectroscopy using combined Kerr gated and shifted excitation Raman difference techniquesJOURNAL OF RAMAN SPECTROSCOPY, Issue 4 2002P. Matousek An exceptionally high level of fluorescence rejection from resonance Raman spectra was achieved using a combination of two techniques, namely Kerr gated temporal rejection with shifted excitation Raman difference spectroscopy. The method was able to recover the resonance Raman spectrum from the intense fluorescence background with a signal-to-noise ratio at least 10 times higher than that achievable with either of the two approaches used individually. To demonstrate the effectiveness of the technique we obtained the resonance Raman spectrum of the laser dye rhodamine 6G (1 × 10,3 mol dm,3) in methanol by excitation at 532 nm and measuring under the maximum of fluorescence emission at 560,590 nm. The method reached the photon shot noise limit of the residual fluorescence providing a detection limit for Raman spectra 106 times lower than the original fluorescence intensity in an accumulation time of 800 s. A unique feature of the experiment was the way in which the optical parametric amplifier light source was configured to alternate automatically between the two excitation wavelengths using an optogalvanic mirror arrangement. The ultra-high sensitivity of the combined approach holds great promise for selective probing of complex biological systems using resonance Raman spectroscopy. Copyright © 2002 John Wiley & Sons, Ltd. [source] Chiral separation of omeprazole and several related benzimidazoles using supercritical fluid chromatographyJOURNAL OF SEPARATION SCIENCE, JSS, Issue 12 2004M. Jesús del Nozal Abstract A study of the enantiomeric separation of omeprazole and several related benzimidazoles, using supercritical fluid chromatography (SFC), on the amylose based column Chiralpak AD is presented in this work. The effect of the organic modifier as well as temperature on the retention and enantioresolution was investigated. Alcohol-type modifiers provided the best results, allowing the enantiomeric separation of all the compounds studied with resolutions that were in most cases higher than 2, and analysis times lower than 10 minutes. An investigation of the temperature effect revealed that the isoelution temperature was below the working temperature range in only two cases, and hence it was better to work at the highest temperature permitted. [source] | ||||||||||||||||||||||||||||