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Sample records for copper-ion release behavior

  1. Cytotoxicity of copper ions released from metal: variation with the exposure period and concentration gradients.

    PubMed

    Cortizo, María Cecilia; Fernández Lorenzo de Mele, Mónica

    2004-01-01

    The aim of this work is to contribute to the elucidation of the cytotoxic process caused by the copper ions released from the biomaterials. Clonal cell lines UMR106 were used in the experiments. Copper ions were obtained from two different sources: copper salts and metal dissolution. Experiments carried out with constant ion concentrations (copper salts) were compared with those with concentrations that vary with time and location (dissolution of the metal). Present results and others previously reported could be interpreted through mathematical models that describe: (1) the variation of concentration of copper ions with time and location within a biofilm and (2) the variation of the killing rate with the concentration of the toxic ion and time. The large number of dead cells found near the copper sample with an average ion concentration below the toxic limit could be interpreted bearing in mind that these cells should be exposed to a local concentration higher than this limit. A logarithmic dependence between the number of cells and exposure time was found for nearly constant ion concentrations. Apparent discrepancies, observed when these results and those of different researchers were contrasted, could be explained considering the dissimilar experimental conditions such as the source of the ions and their local concentration at real time.

  2. [Study on the release of copper ion and corrosion for intrauterine contraceptive device with two kinds of Cu-containing stent].

    PubMed

    Zou, Fengping; Huang, Shuze; Ji, Rong; Ding, Biao; Yao, Tianping

    2014-05-01

    Two kinds of Cu-containing intrauterine contraceptive device (Cu-IUD) has been evaluated through the study on the release of copper ion and corrosion of copper surface in artificially formulated fluid. The result showed that the copper ions were released profusely from the stainless steel stents Cu-IUD in the first week of soak (25-12 microg/d), and then it became slowly and steady. The release of the copper ions from the titanium nickel shape memory alloy stents Cu-IUD were always slowly and steady in two months (0.5-5 microg/d). It obviously shows that the corrosion on copper surface of stainless steel stents Cu-IUD were more serious than titanium nickel shape memory alloy stents Cu-IUD by using 200 times microscope testing before and after soaking in formulated fluid.

  3. Effective inhibition of the early copper ion burst release with ultra-fine grained copper and single crystal copper for intrauterine device application.

    PubMed

    Xu, X X; Nie, F L; Wang, Y B; Zhang, J X; Zheng, W; Li, L; Zheng, Y F

    2012-02-01

    To solve the main problems of existing coarse grained copper (CG Cu) intrauterine devices (IUD)-namely burst release and a low transfer efficiency of the cupric ions during usage-ultra-fine grained copper (UFG Cu) and single crystal copper (SC Cu) have been investigated as potential substitutes. Their corrosion properties with CG Cu as a control have been studied in simulated uterine fluid (SUF) under different conditions using electrochemical measurement methods. Long-term immersion of UFG Cu, SC Cu and CG Cu samples in SUF at 37 °C have been studied for 300 days. A lower copper ion burst release and a higher efficiency release of cupric ions were observed for UFG Cu and SC Cu compared with CG Cu in the first month of immersion and 2 months later. The respective corrosion mechanisms for UFG Cu, SC Cu and CG Cu in SUF are proposed. In vitro biocompatibility tests show a better cellular response to UFG Cu and SC Cu than CG Cu. In terms of instantaneous corrosion behavior, long-term corrosion performance and in vitro biocompatibility, the three pure copper materials follow the order: UFG Cu>SC Cu>CG Cu, which indicates that UFG Cu could be the most suitable candidate material for intrauterine devices.

  4. Reduction of copper ions release by a novel ecofriendly electropolymerized nanolayer obtained from a natural compound (carvacrol).

    PubMed

    Bertuola, M; Grillo, C A; Fernández Lorenzo de Mele, M

    2016-08-05

    The release of copper ions by copper-containing devices, equipments and facilities represents a potential risk for biological systems. Different inhibitory treatments (CuIT) that use organic compounds have been proposed to reduce this environmental hazard but many of them are not in accordance with new regulations. The development of an ecofriendly CuIT based on the use of carvacrol, a natural phenolic compound present in essential oils, is reported here. The effects of carvacrol adsorption (adCarv) and its electropolymerization (polyCarv) were examined. Electropolymerization was attained after cycling the copper electrode in the 0.3-1.0V potential range. Electrochemical techniques complemented by ATR-FTIR, XPS, SEM and AFM surface analyses were used to evaluate the composition and characteristics of the layers. Results demonstrated that adCarv includes cetonic structures while polyCarv additionally contains ether bonds. AFM and SEM observations showed the presence of round nanoglobules, larger for adCarv (close to 50nm diameter). Cytotoxicity of adCarv and polyCarv layers on copper was also evaluated. The comparative analysis of both treatments revealed that polyCarv nanolayer is highly protective while the adCarv layer is weakly protective and reduction in cell viability was found. It was concluded that CuIT that leads to polyCarv nanolayer is very effective and ecofriendly.

  5. Selective extraction and release using (EDTA-Ni)-layered double hydroxide coupled with catalytic oxidation of 3,3',5,5'-tetramethylbenzidine for sensitive detection of copper ion.

    PubMed

    Tang, Sheng; Chang, Yuepeng; Chia, Guo Hui; Lee, Hian Kee

    2015-07-23

    Copper is an important heavy metal in various biological processes. Many methods have been developed for detecting of copper ions (Cu(2+)) in aqueous samples. However, an easy, cheap, selective and sensitive method is still desired. In this study, a selective extraction-release-catalysis approach has been developed for sensitive detection of copper ion. Ethylenediaminetetraacetic acid (EDTA) chelated with nickel ion (Ni(2+)) were intercalated in a layered double hydroxide via a co-precipitation reaction. The product was subsequently applied as sorbent in dispersive solid-phase extraction for the enrichment of Cu(2+) at pH 6. Since Cu(2+) has a stronger complex formation constant with EDTA, Ni(2+) exchanged with Cu(2+) selectively. The resulting sorbent containing Cu(2+) was transferred to catalyze the 3,3',5,5'-tetramethylbenzidine oxidation reaction, since Cu(2+) could be released by the sorbent effectively and has high catalytic ability for the reaction. Blue light emitted from the oxidation product was measured by ultraviolet-visible spectrophotometry for the determination of Cu(2+). The extraction temperature, extraction time, and catalysis time were optimized. The results showed that this method provided a low limit of detection of 10nM, a wide linear range (0.05-100μM) and good linearity (r(2)=0.9977). The optimized conditions were applied to environmental water samples. Using Cu(2+) as an example, this work provided a new and interesting approach for the convenient and efficient detection of metal cations in aqueous samples.

  6. Behavior and fate of copper ions in an anammox granular sludge reactor and strategies for remediation.

    PubMed

    Zhang, Zheng-Zhe; Deng, Rui; Cheng, Ya-Fei; Zhou, Yu-Huang; Buayi, Xiemuguli; Zhang, Xian; Wang, Hui-Zhong; Jin, Ren-Cun

    2015-12-30

    In this study, the behavior, distribution and form dynamics of overloaded Cu(II) in anaerobic ammonium oxidation (anammox) granular sludge reactors were investigated. The performance and physiological characteristics were tracked by continuous-flow monitoring to evaluate the long-term effects. High Cu loading (0.24 g L(-1)d(-1)) exceeded sludge bearing capacity, and precipitation dominated the removal pathway. The Cu distribution migrated from the extracellular polymeric substances-bound to the cell-associated Cu and the Cu forms shifted from the weakly bound to strongly bound fractions over time. Pearson correlation and fluorescence spectra analyses showed that the increase in protein concentrations in the EPS was a clear self-defense response to Cu(II) stress. Two remediation strategies, i.e., ethylenediamine tetraacetic acid (EDTA) washing and ultrasound-enhanced EDTA washing, weakened the equilibrium metal partition coefficient from 5.8 to 0.45 and 0.34 L mg(-1)SS, respectively, thereby accelerating the external diffusion of the Cu that had accumulated in the anammox granules.

  7. Hydrogen release behavior.

    SciTech Connect

    LaChance, Jeffrey L.; Dedrick, Daniel E.; Keller, Jay O.; Evans, Gregory Herbert; Houf, William G.; Winters, William Stanley, Jr.; Ruggles, A.; Zhang, J.

    2010-04-01

    The summary of this presentation is: (1) Barrier walls are used to reduce setbacks by factor of 2; (2) We found no ignition-timing vs. over-pressure sensitivities for jet flow obstructed by barrier walls; (3) Cryogenic vapor cloud model indicates hazard length scales exceed the room-temperature release; validation experiments are required to confirm; (4) Light-up maps developed for lean limit ignition; flammability factor model provides good indication of ignition probability; and (5) Auto-ignition is enhanced by blunt-body obstructions - increases gas temperature and promotes fuel/air mixing.

  8. Copper ion liquid-like thermoelectrics.

    PubMed

    Liu, Huili; Shi, Xun; Xu, Fangfang; Zhang, Linlin; Zhang, Wenqing; Chen, Lidong; Li, Qiang; Uher, Ctirad; Day, Tristan; Snyder, G Jeffrey

    2012-03-11

    Advanced thermoelectric technology offers a potential for converting waste industrial heat into useful electricity, and an emission-free method for solid state cooling. Worldwide efforts to find materials with thermoelectric figure of merit, zT values significantly above unity, are frequently focused on crystalline semiconductors with low thermal conductivity. Here we report on Cu(2-x)Se, which reaches a zT of 1.5 at 1,000 K, among the highest values for any bulk materials. Whereas the Se atoms in Cu(2-x)Se form a rigid face-centred cubic lattice, providing a crystalline pathway for semiconducting electrons (or more precisely holes), the copper ions are highly disordered around the Se sublattice and are superionic with liquid-like mobility. This extraordinary 'liquid-like' behaviour of copper ions around a crystalline sublattice of Se in Cu(2-x)Se results in an intrinsically very low lattice thermal conductivity which enables high zT in this otherwise simple semiconductor. This unusual combination of properties leads to an ideal thermoelectric material. The results indicate a new strategy and direction for high-efficiency thermoelectric materials by exploring systems where there exists a crystalline sublattice for electronic conduction surrounded by liquid-like ions.

  9. Solution structure of copper ion-induced molecular aggregates of tyrosine melanin.

    PubMed

    Gallas, J M; Littrell, K C; Seifert, S; Zajac, G W; Thiyagarajan, P

    1999-08-01

    Melanin, the ubiquitous biological pigment, provides photoprotection by efficient filtration of light and also by its antioxidant behavior. In solutions of synthetic melanin, both optical and antioxidant behavior are affected by the aggregation states of melanin. We have utilized small-angle x-ray and neutron scattering to determine the molecular dimensions of synthetic tyrosine melanin in its unaggregated state in D(2)O and H(2)O to study the structure of melanin aggregates formed in the presence of copper ions at various copper-to-melanin molar ratios. In the absence of copper ions, or at low copper ion concentrations, tyrosine melanin is present in solution as a sheet-like particle with a mean thickness of 12.5 A and a lateral extent of approximately 54 A. At a copper-to-melanin molar ratio of 0.6, melanin aggregates to form long, rod-like structures with a radius of 32 A. At a higher copper ion concentration, with a copper-to-melanin ratio of 1.0, these rod-like structures further aggregate, forming sheet-like structures with a mean thickness of 51 A. A change in the charge of the ionizable groups induced by the addition of copper ions is proposed to account for part of the aggregation. The data also support a model for the copper-induced aggregation of melanin driven by pi stacking assisted by peripheral Cu(2+) complexation. The relationship between our results and a previous hypothesis for reduced cellular damage from bound-to-melanin redox metal ions is also discussed.

  10. Solution structure of copper ion-induced molecular aggregates of tyrosine melanin.

    PubMed Central

    Gallas, J M; Littrell, K C; Seifert, S; Zajac, G W; Thiyagarajan, P

    1999-01-01

    Melanin, the ubiquitous biological pigment, provides photoprotection by efficient filtration of light and also by its antioxidant behavior. In solutions of synthetic melanin, both optical and antioxidant behavior are affected by the aggregation states of melanin. We have utilized small-angle x-ray and neutron scattering to determine the molecular dimensions of synthetic tyrosine melanin in its unaggregated state in D(2)O and H(2)O to study the structure of melanin aggregates formed in the presence of copper ions at various copper-to-melanin molar ratios. In the absence of copper ions, or at low copper ion concentrations, tyrosine melanin is present in solution as a sheet-like particle with a mean thickness of 12.5 A and a lateral extent of approximately 54 A. At a copper-to-melanin molar ratio of 0.6, melanin aggregates to form long, rod-like structures with a radius of 32 A. At a higher copper ion concentration, with a copper-to-melanin ratio of 1.0, these rod-like structures further aggregate, forming sheet-like structures with a mean thickness of 51 A. A change in the charge of the ionizable groups induced by the addition of copper ions is proposed to account for part of the aggregation. The data also support a model for the copper-induced aggregation of melanin driven by pi stacking assisted by peripheral Cu(2+) complexation. The relationship between our results and a previous hypothesis for reduced cellular damage from bound-to-melanin redox metal ions is also discussed. PMID:10423458

  11. Lipopolysaccharide enhances oxidative modification of low density lipoprotein by copper ions, endothelial and smooth muscle cells.

    PubMed

    Maziere, C; Conte, M A; Dantin, F; Maziere, J C

    1999-03-01

    The effect of lipopolysaccharide (LPS, endotoxin) on low density lipoprotein (LDL) oxidative modification by copper ions, endothelial and smooth muscle cells was studied by determination of the level of lipid peroxidation products (thiobarbituric acid reactive substances or TBARS), the diene level and the electrophoretic mobility of the LDL particle. LPS 25-75 microg/ml induced a dose-dependent increase in LDL oxidation by copper ions, endothelial and smooth muscle cells. At 75 microg LPS/ml, the TBARS content was 1.9, 1.6, and 1.8-fold increased, respectively. The LDL degradation by J774 macrophage-like cells was concomitantly stimulated. Preincubation of the LDL particle with LPS induced a marked increase in the subsequent LDL oxidative modification either by copper ions or by endothelial and smooth muscle cells. In addition, pretreatment of endothelial and smooth muscle cells with LPS also induced an enhancement of LDL oxidative modification performed in the absence of LPS. This effect was accompanied by a parallel increase in superoxide anion release by the cells. These results point at one of the mechanisms involved in the described association between bacterial infection and acute myocardial infarction as well as coronary heart disease.

  12. Comparison and distribution of copper oxide nanoparticles and copper ions in activated sludge reactors.

    PubMed

    Zhang, Dongqing; Trzcinski, Antoine P; Oh, Hyun-Suk; Chew, Evelyn; Tan, Soon Keat; Ng, Wun Jern; Liu, Yu

    2017-02-16

    Copper oxide nanoparticles (CuO NPs) are being increasingly applied in the industry which results inevitably in the release of these materials into the hydrosphere. In this study, simulated waste-activated sludge experiments were conducted to investigate the effects of Copper Oxide NPs at concentrations of 0.1, 1, 10 and 50 mg/L and to compare it with its ionic counterpart (CuSO4). It was found that 0.1 mg/L of CuO NPs had negligible effects on Chemical Oxygen Demand (COD) and ammonia removal. However, the presence of 1, 10 and 50 mg/L of CuO NPs decreased COD removal from 78.7% to 77%, 52.1% and 39.2%, respectively (P < 0.05). The corresponding effluent ammonium (NH4-N) concentration increased from 14.9 mg/L to 18, 25.1 and 30.8 mg/L, respectively. Under equal Cu concentration, copper ions were more toxic towards microorganisms compared to CuO NPs. CuO NPs were removed effectively (72-93.2%) from wastewater due to a greater biosorption capacity of CuO NPs onto activated sludge, compared to the copper ions (55.1-83.4%). The SEM images clearly showed the accumulation and adsorption of CuO NPs onto activated sludge. The decrease in Live/dead ratio after 5 h of exposure of CuO NPs and Cu(2+) indicated the loss of cell viability in sludge flocs.

  13. Nanopore detection of copper ions using a polyhistidine probe.

    PubMed

    Wang, Guihua; Wang, Liang; Han, Yujing; Zhou, Shuo; Guan, Xiyun

    2014-03-15

    We report a stochastic nanopore sensing method for the detection of Cu(2+) ions. By employing a polyhistidine molecule as a chelating agent, and based on the different signatures of the events produced by the translocation of the chelating agent through an α-hemolysin pore in the absence and presence of target analytes, trace amounts of copper ions could be detected with a detection limit of 40 nM. Importantly, although Co(2+), Ni(2+), and Zn(2+) also interacts with the polyhistidine molecule, since the event residence times and/or blockage amplitudes for these metal chelates are significantly different from those of copper chelates, these metal ions do not interfere with Cu(2+) detection. This chelating reaction approach should find useful application in the development of nanopore sensors for other metal ions.

  14. Equilibrium studies of copper ion adsorption onto palm kernel fibre.

    PubMed

    Ofomaja, Augustine E

    2010-07-01

    The equilibrium sorption of copper ions from aqueous solution using a new adsorbent, palm kernel fibre, has been studied. Palm kernel fibre is obtained in large amounts as a waste product of palm oil production. Batch equilibrium studies were carried out and system variables such as solution pH, sorbent dose, and sorption temperature were varied. The equilibrium sorption data was then analyzed using the Langmuir, Freundlich, Dubinin-Radushkevich (D-R) and Temkin isotherms. The fit of these isotherm models to the equilibrium sorption data was determined, using the linear coefficient of determination, r(2), and the non-linear Chi-square, chi(2) error analysis. The results revealed that sorption was pH dependent and increased with increasing solution pH above the pH(PZC) of the palm kernel fibre with an optimum dose of 10g/dm(3). The equilibrium data were found to fit the Langmuir isotherm model best, with a monolayer capacity of 3.17 x 10(-4)mol/g at 339K. The sorption equilibrium constant, K(a), increased with increasing temperature, indicating that bond strength between sorbate and sorbent increased with temperature and sorption was endothermic. This was confirmed by the increase in the values of the Temkin isotherm constant, B(1), with increasing temperature. The Dubinin-Radushkevich (D-R) isotherm parameter, free energy, E, was in the range of 15.7-16.7kJ/mol suggesting that the sorption mechanism was ion exchange. Desorption studies showed that a high percentage of the copper was desorbed from the adsorbent using acid solutions (HCl, HNO(3) and CH(3)COOH) and the desorption percentage increased with acid concentration. The thermodynamics of the copper ions/palm kernel fibre system indicate that the process is spontaneous and endothermic.

  15. Enhanced nonlinear optical characteristics of copper-ion-doped double crossover DNAs

    NASA Astrophysics Data System (ADS)

    Park, Byeongho; Lee, Byung Jic; Dugasani, Sreekantha Reddy; Cho, Youngho; Kim, Chulki; Seo, Minah; Lee, Taikjin; Jhon, Young Min; Choi, Jaebin; Lee, Seok; Park, Sung Ha; Jun, Seong Chan; Yeom, Dong-Il; Rotermund, Fabian; Kim, Jae Hun

    2015-10-01

    The modification of deoxyribonucleic acid (DNA) samples by sequencing the order of bases and doping copper ions opens the possibility for the design of novel nanomaterials exhibiting large optical nonlinearity. We investigated the nonlinear characteristics of copper-ion doped double crossover DNA samples for the first time to the best of our knowledge by using Z-scan and four-wave mixing methods. To accelerate the nonlinear characteristics, we prepared two types of unique DNA nanostructures composed of 148 base pairs doped with copper ions with a facile annealing method. The outstanding third-order nonlinear optical susceptibility of the copper-ion-doped DNA solution, 1.19 × 10-12 esu, was estimated by the conventional Z-scan measurement, whereas the four-wave mixing experiment was also investigated. In the visible spectral range, the copper-ion-doped DNA solution samples provided competent four-wave mixing signals with a remarkable conversion efficiency of -4.15 dB for the converted signal at 627 nm. The interactions between DNA and copper ions contribute to the enhancement of nonlinearity due to structural and functional changes. The present study signifies that the copper-ion-doped double crossover DNA is a potential candidate as a highly efficient novel material for further nonlinear optical applications.

  16. Als1 and Als3 regulate the intracellular uptake of copper ions when Candida albicans biofilms are exposed to metallic copper surfaces.

    PubMed

    Zheng, Sha; Chang, Wenqiang; Li, Chen; Lou, Hongxiang

    2016-05-01

    Copper surfaces possess efficient antimicrobial effect. Here, we reported that copper surfaces could inactivate Candida albicans biofilms within 40 min. The intracellular reactive oxygen species in C. albicans biofilms were immediately stimulated during the contact of copper surfaces, which might be an important factor for killing the mature biofilms. Copper release assay demonstrated that the copper ions automatically released from the surface of 1 mm thick copper coupons with over 99.9% purity are not the key determinant for the copper-mediated killing action. The susceptibility test to copper surfaces by using C. albicans mutant strains, which were involved in efflux pumps, adhesins, biofilms formation or osmotic stress response showed that als1/als1 and als3/als3 displayed higher resistance to the copper surface contact than other mutants did. The intracellular concentration of copper ions was lower in als1/als1 and als3/als3 than that in wild-type strain. Transcriptional analysis revealed that the expression of copper transporter-related gene, CRP1, was significantly increased in als1/als1, als3/als3, suggesting a potential role of ALS1 and ALS3 in absorbing ions by regulating the expression of CRP1 This study provides a potential application in treating pathogenic fungi by using copper surfaces and uncovers the roles of ALS1 and ALS3 in absorbing copper ions for C. albicans.

  17. [Metabolic memory enhances hormesis effect to the copper ions in age-depended manner].

    PubMed

    Bozhkov, A I; Sidorov, V I; Kurguzova, N I; Dlubovskaia, V L

    2014-01-01

    The ability of young and old rats to manifest the hormesis effect to lethal doses of copper sulphate and the ability to save the induced "adaptive" pattern of redistribution of copper ions after the transfer of animals in the standard conditions is the mechanism of metabolic memory. It was found that pretreatment of animals with low-dose (1 mg per 100 g body mass, i.e. 33% of the lethal dose) of copper sulfate induced the formation of their resistance to lethal doses (3 mg per 100 g), so the hormesis effect was manifested. Hormesis effect depended on the number of pre injections of small doses of copper sulphate in an S-shaped manner. The protective effect increased after 1 to 3 of preliminary injections of copper sulfate, and after four or more injections the hormesis effect decreased. It is shown that the cardinal role in intracellular pattern of copper ion redistribution play heat-stable copper binding proteins 12 kDa cytosolic proteins. The formed "adaptive" pattern of intracellular distribution of the copper ions may be reproduced, after at least, one month. The prolonged hormesis effect can be attributed to the forming metabolic memory. The intracellular distribution pattern of the copper ions was age-dependent. Age-related differences were found in hormesis effect induced by copper ions, which results in increased binding capacity of copper binding proteins in old animals, with a higher content of copper ions in the mitochondria and microsomes as compared to young animals.

  18. Sensitive signal-on fluorescent sensing for copper ions based on the polyethyleneimine-capped silver nanoclusters-cysteine system.

    PubMed

    Zhang, Na; Qu, Fei; Luo, Hong Qun; Li, Nian Bing

    2013-08-12

    In this work, we present a label-free sensor for copper ions. This sensor is composed of silver nanoclusters and cysteine. The fluorescence of the silver nanoclusters was quenched by cysteine, which was recovered in the presence of copper ions. This binding of silver nanoclusters to cysteine promoted agglomeration of silver nanoclusters to yield larger non-fluorescent silver nanoparticles. The presence of copper ions resulted in the oxidation of cysteine to form a disulfide compound, leading to recovery of fluorescence of the silver nanoclusters. The fluorescence of the silver nanoclusters in the presence of cysteine increased with increasing concentration of copper ions in the range of 10-200 nM. The detection limit of this sensor for copper ions was 2.3 nM. The silver nanoclusters-cysteine sensor provides a simple, cost-effective, and sensitive platform for the detection of copper ions.

  19. Heavy metals and human spermatozoa. III. The toxicity of copper ions for spermatozoa.

    PubMed

    Holland, M K; White, I G

    1988-12-01

    The dissolution of copper ions from copper metal into a saline medium in vitro was quantified using a colourimetric assay. The presence of spermatozoa enhanced this dissolution and increasing the protein content of the medium further increased the rate of dissolution. Approximately 17% of the copper released was either tightly bound to the spermatozoa or was within the cell and could not be removed by repeated washing. Once spermatozoa were immobilized, they could not be revived by washing and repeated changes of medium, by addition of copper specific-chelating agent or by extensive dialysis. When the toxicity to spermatozoa of cuprous and cupric ions was compared with copper metal, it could be shown that the quantity of cupric ions required (0.2-0.4 mg/ml) was in excess of the total quantity of copper released into solution. The quantity of cuprous ion required (0.08-0.16 mg/ml) to exert similar toxic effects to copper, was within the range of copper released from the metal. Under the conditions of this study, it is possible that cuprous ion would be oxidised to the cupric form generating free radicals in the process. It is not known whether the toxic effect is due to the cuprous ion, per se, or to radicals generated in its oxidation. Increasing the protein content of the medium to levels similar to low (8 mg/ml) and high (64 mg/ml) values reported in human uterine fluid increased the dissolution rate of copper but also offered some protection against the toxic effects of copper metal and cuprous and cupric ions.

  20. Reactivity of food phenols with iron and copper ions: binding, dioxygen activation and oxidation mechanisms.

    PubMed

    Nkhili, Ezzohra; Loonis, Michèle; Mihai, Simona; El Hajji, Hakima; Dangles, Olivier

    2014-06-01

    In this work, the affinity of common dietary phenols (gallic acid, caffeic acid, catechin, and rutin) for iron and copper ions was quantitatively investigated in neutral phosphate buffer as well as the reactivity of the complexes toward dioxygen. Contrasting behaviors were observed: because of the competing phosphate ions, Fe(III) binding is much slower than Fe(II) binding, which is rapidly followed by autoxidation of Fe(II) into Fe(III). With both ions, O2 consumption and H2O2 production are modest and the phenolic ligands are only slowly oxidized. By contrast, metal-phenol binding is fast with both Cu(I) and Cu(II). With Cu(I), O2 consumption and H2O2 production are very significant and the phenolic ligands are rapidly oxidized into a complex mixture of oligomers. The corresponding mechanism with Cu(II) is hampered by the preliminary rate-determining step of Cu(II) reduction by the phenols. The consequences of these findings for the stability and antioxidant activity of plant phenols are discussed.

  1. Electro-enhanced removal of copper ions from aqueous solutions by capacitive deionization.

    PubMed

    Huang, Shu-Yun; Fan, Chen-Shiuan; Hou, Chia-Hung

    2014-08-15

    This study was performed to determine the feasibility of electrosorptive removal of copper ions from aqueous solutions using a capacitive deionization process. The electrosorptive potential of copper ions was determined using cyclic voltammetry measurements, and copper electrodeposition could be suppressed at a voltage less than 0.8 V. Importantly, the experimental results demonstrated a significant enhancement of electrosorption capability of copper ions using the activated carbon electrodes under electro-assistance, associated with electrical double-layer charging. At 0.8 V, the equilibrium electrosorption capacity was enhanced to 24.57 mg/g based on the Langmuir model, and the electrosorption constant rate was increased to 0.038 min(-1) simulated by a first-order kinetics model. Moreover, the activated carbon electrode showed great regeneration performance for the removal of low level copper ions. Additional experiments regarding electrosorption selectivity were performed in the presence of sodium chloride, natural organic matter, or dissolved silica. Copper ions that were preferentially electroadsorbed on the electrode surface can be effectively removed in a competitive environment. Therefore, the electrosorption process using activated carbon electrodes can be recommended to treat copper solutions at low concentrations for wastewater treatment and water purification.

  2. Shock loading and release behavior of silicon nitride

    NASA Astrophysics Data System (ADS)

    Kawai, N.; Tsuru, T.; Hidaka, N.; Liu, X.; Mashimo, T.

    2017-01-01

    Shock-reshock and shock-release experiments were performed on silicon nitride ceramics above and below its phase transition pressure. Experimental results clearly show the occurrence of elastic-plastic transition and phase transition during initial shock loading. The HEL and phase transition stress are determined as 11.6 and 34.5 GPa, respectively. Below the phase transition stress, the reshock profile consists of the single shock with short rise time, while the release profile shows the gradual release followed by rapid one. Above phase transition stress, reshock and release behavior varies with the initial shock stress. In the case of reshock and release from about 40 GPa, the reshock structure is considerably dispersed, while the release structure shows rapid release. In the reshock profile from about 50 GPa, the formation of the shock wave with the small ramped precursor is observed. And, the release response from same shocked condition shows initial gradual release and subsequent quite rapid one. These results would provide the information about how phase transformation kinetics effects on the reshock and release behavior.

  3. Fabrication of interfacial functionalized porous polymer monolith and its adsorption properties of copper ions.

    PubMed

    Han, Jiaxi; Du, Zhongjie; Zou, Wei; Li, Hangquan; Zhang, Chen

    2014-07-15

    The interfacial functionalized poly (glycidyl methacrylate) (PGMA) porous monolith was fabricated and applied as a novel porous adsorbent for copper ions (Cu(2+)). PGMA porous material with highly interconnected pore network was prepared by concentrated emulsion polymerization template. Then polyacrylic acid (PAA) was grafted onto the interface of the porous monolith by the reaction between the epoxy group on PGMA and a carboxyl group on PAA. Finally, the porous monolith was interfacial functionalized by rich amount of carboxyl groups and could adsorb copper ions effectively. The chemical structure and porous morphology of the porous monolith were measured by Fourier transform infrared spectroscopy and scanning electron microscopy. Moreover, the effects of pore size distribution, pH value, co-existing ions, contacting time, and initial concentrations of copper ions on the adsorption capacity of the porous adsorbents were studied.

  4. The role of copper ions in pathophysiology and fluorescent sensors for the detection thereof.

    PubMed

    Verwilst, Peter; Sunwoo, Kyoung; Kim, Jong Seung

    2015-04-04

    Copper ions are indispensible to life and maintaining tight control over the homeostasis of copper ions in the body is a prerequisite to sustaining health. Aberrations in normal copper levels, both systemic as well as on a tissue or cellular scale, are implicated in a wide range of diseases, such as Menkes disease, Wilson's disease, Alzheimer's disease, Parkinson's disease and transmissible spongiform encephalopathy (prion diseases). The current understanding of how copper influences these diseases is described. The field of fluorescent copper sensors both functioning via a reaction based mechanism as well as by directly binding copper ions has known an inflation in recent years, and the importance of this field to elucidating the role of copper in cell biology is pointed out. Progress in these tightly interwoven fields has resulted in a better understanding of a number of diseases related to copper imbalances and current developments might open the path for novel and innovating therapies to address these diseases.

  5. Circadian regulation of cortisol release in behaviorally split golden hamsters.

    PubMed

    Lilley, Travis R; Wotus, Cheryl; Taylor, Daniel; Lee, Jennifer M; de la Iglesia, Horacio O

    2012-02-01

    The master circadian clock located within the hypothalamic suprachiasmatic nucleus (SCN) is necessary for the circadian rhythm of glucocorticoid (GC) release. The pathways by which the SCN sustains rhythmic GC release remain unclear. We studied the circadian regulation of cortisol release in the behaviorally split golden hamster, in which the single bout of circadian locomotor activity splits into two bouts approximately 12 h apart after exposing the animals to constant light conditions. We show that unsplit control hamsters present a single peak of cortisol release that is concomitant with a single peak of ACTH release. In contrast, split hamsters show two peaks of cortisol release that are approximately 12 h appart and are appropriately phased to each locomotor activity bout but surprisingly do not rely on rhythmic release of ACTH. Our results are consistent with a model in which the circadian pacemaker within the SCN regulates the circadian release of GC via input to the hypothalamo-pituitary-adrenal axis and via a second regulatory pathway, which likely involves sympathetic innervation of the adrenal and can operate even in the absence of ACTH circadian rhythmic release. Furthermore, we show that although the overall 24-h cortisol output in split hamsters is lower than in unsplit controls, split hamsters release constant low levels of ACTH. This result suggests that the timing, rather than the absolute amount, of cortisol release is more critical for the induction of negative feedback effects that regulate the hypothalamo-pituitary-adrenal axis.

  6. Combined effects of water temperature and copper ion concentration on catalase activity in Crassostrea ariakensis

    NASA Astrophysics Data System (ADS)

    Wang, Hui; Yang, Hongshuai; Liu, Jiahui; Li, Yanhong; Liu, Zhigang

    2015-07-01

    A central composite experimental design and response surface method were used to investigate the combined effects of water temperature (18-34°C) and copper ion concentration (0.1-1.5 mg/L) on the catalase (CAT) activity in the digestive gland of Crassostrea ariakensis. The results showed that the linear effects of temperature were significant ( P<0.01), the quadratic effects of temperature were significant ( P<0.05), the linear effects of copper ion concentration were not significant ( P>0.05), and the quadratic effects of copper ion concentration were significant ( P<0.05). Additionally, the synergistic effects of temperature and copper ion concentration were not significant ( P>0.05), and the effect of temperature was greater than that of copper ion concentration. A model equation of CAT enzyme activity in the digestive gland of C. ariakensis toward the two factors of interest was established, with R 2, Adj. R 2 and Pred. R 2 values as high as 0.943 7, 0.887 3 and 0.838 5, respectively. These findings suggested that the goodness of fit to experimental data and predictive capability of the model were satisfactory, and could be practically applied for prediction under the conditions of the study. Overall, the results suggest that the simultaneous variation of temperature and copper ion concentration alters the activity of the antioxidant enzyme CAT by modulating active oxygen species metabolism, which may be utilized as a biomarker to detect the effects of copper pollution.

  7. UV spectroscopy determination of aqueous lead and copper ions in water

    NASA Astrophysics Data System (ADS)

    Tan, C. H.; Moo, Y. C.; Mat Jafri, M. Z.; Lim, H. S.

    2014-05-01

    Lead (Pb2+) and copper (Cu2+) ions are very common pollutants in water which have dangerous potential causing serious disease and health problems to human. The aim of this paper is to determine lead and copper ions in aqueous solution using direct UV detection without chemical reagent waste. This technique allow the determination of lead and copper ions from range 0.2 mg/L to 10 mg/L using UV wavelength from 205 nm to 225 nm. The method was successfully applied to synthetic sample with high performance.

  8. Magnetic Interactions in the Copper Complex (L-Aspartato)(1,10-phenanthroline)copper(II) Hydrate. An Exchange-Coupled Extended System with Two Dissimilar Copper Ions.

    PubMed

    Brondino, Carlos D.; Calvo, Rafael; Atria, Ana María; Spodine, Evgenia; Nascimento, Otaciro R.; Peña, Octavio

    1997-07-02

    We report EPR measurements in single-crystal samples at the microwave frequencies 9.8 and 34.3 GHz and magnetic susceptibility measurements in polycrystalline samples for the ternary complex of copper with aspartic acid and phenanthroline, (L-aspartato)(1,10-phenanthroline)copper(II) hydrate. The crystal lattice of this compound is composed of two dissimilar copper ions identified as Cu(A) and Cu(B), which are in two types of copper chains called A and B, respectively, running parallel to the b crystal axis. The copper ions in the A chains are connected by the aspartic acid molecule, and those in the B chains by a chemical path that involves a carboxylate bridge and a hydrogen bond. Both chains are held together by a complex network of hydrogen bonds and by hydrophobic interactions between aromatic amines. Magnetic susceptibility data indicate a Curie-Weiss behavior in the studied temperature range (2-300 K). The EPR spectra at 9.8 GHz display a single exchange collapsed resonance for any magnetic field orientation, in the so-called strong exchange regime. Those at 34.3 GHz are within the so-called weak exchange regime and display two resonances which belong to each type of copper ion chain. The decoupling of the spectra at 34.3 GHz using a theory based on Anderson's model for the case of two weakly exchange coupled spins S = (1)/(2) allows one to obtain the angular variation of the squares of the g-factor and the peak-to-peak line width of each resonance. This model also allows one to evaluate the exchange parameter |J(AB)/k| = 2.7(6) mK associated with the chemical path connecting dissimilar copper ions. The line width data obtained for each component of the spectra at 34.3 GHz are analyzed in terms of a model based on Kubo and Tomita's theory, to obtain the exchange parameters |J(A)/k| = 0.77(2) K and |J(B)/k| = 1.44(2) K associated with the chemical paths connecting the similar copper ions of types A and B, respectively.

  9. Evaluation of copper ion of antibacterial effect on Pseudomonas aeruginosa, Salmonella typhimurium and Helicobacter pylori and optical, mechanical properties

    NASA Astrophysics Data System (ADS)

    Kim, Young-Hwan; Choi, Yu-ri; Kim, Kwang-Mahn; Choi, Se-Young

    2012-02-01

    Antibacterial effect on Pseudomonas aeruginosa, Salmonella typhimurium and Helicobacter pylori of copper ion was researched. Also, additional effects of copper ion coating on optical and mechanical properties were researched as well. Copper ion was coated on glass substrate as a thin film to prevent bacteria from growing. Cupric nitrate was used as precursors for copper ion. The copper ion contained sol was deposited by spin coating process on glass substrate. Then, the deposited substrates were heat treated at the temperature range between 200 °C and 250 °C. The thickness of deposited copper layer on the surface was 63 nm. The antibacterial effect of copper ion coated glass on P. aeruginosa, S. typhimurium and H. pylori demonstrated excellent effect compared with parent glass. Copper ion contained layer on glass showed a similar value of transmittance compared with value of parent glass. The 3-point bending strength and Vickers hardness were 209.2 MPa, 540.9 kg/mm2 which were about 1.5% and 1.3% higher than the value of parent glass. From these findings, it is clear that copper ion coating on glass substrate showed outstanding effect not only in antibacterial activity but also in optical and mechanical properties as well.

  10. Phasic dopamine release in appetitive behaviors and drug abuse

    PubMed Central

    Wanat, Matthew J.; Willuhn, Ingo; Clark, Jeremy J.; Phillips, Paul E. M.

    2010-01-01

    Short phasic bursts of neuronal activity in dopamine neurons produce rapid and transient increases in extracellular dopamine concentrations throughout the mesocorticolimbic system, which are associated with the initiation of goal-directed behaviors. It is well established that acute exposure to many addictive drugs produce increases in tonic dopamine levels that occur on the order of minutes. However, recent studies suggest that abused drugs similarly enhance phasic dopamine release events that occur on a subsecond time scale. Furthermore, drug experience modulates the synaptic and intrinsic properties of dopamine neurons, which could affect dopamine burst firing and phasic dopamine release. This review will provide a general introduction to the mesolimbic dopamine system, as well as the primary methods used to detect dopamine neurons and dopamine release. We present the role of phasic dopamine release in appetitive behaviors in the context of contemporary theories regarding the function of dopamine. Next we discuss the known drug-induced changes to dopamine neurons and phasic release in both in vitro and in vivo preparations. Finally, we offer a simple model that chronic drug experience attenuates tonic/basal dopamine levels but promotes phasic dopamine release, which may result in aberrant goal-directed behaviors contributing to the development of addiction. PMID:19630749

  11. Drug release behavior from nanoporous anodic aluminum oxide.

    PubMed

    Kwak, Dae-Hyun; Yoo, Ji-Beom; Kim, Deug Joong

    2010-01-01

    In this study, we developed a new drug delivery system using anodic oxidation. The growth of a porous oxide layer on aluminum under anodic bias in various electrolytes has been studied for more than 40 years. Anodic Aluminum Oxide (AAO) has many uniform nanopores on its surface. This nanoporous surface can be used for drug storage. The effects of the diameter and depth of the AAO on the release characteristics of a drug were investigated. Paclitaxel was used for the drug loading and release test. Paclitaxel was loaded on the inside of the AAO by ultrasonication. The amount of the drug released from the AAO was analyzed by high performance liquid chromatography (HPLC). The pore size did not affect the drug release behavior. However, the depth of the pores had a significant influence on the release rate of the drug.

  12. Cellular prion protein acquires resistance to proteolytic degradation following copper ion binding.

    PubMed

    Kuczius, Thorsten; Buschmann, Anne; Zhang, Wenlan; Karch, Helge; Becker, Karsten; Peters, Georg; Groschup, Martin H

    2004-08-01

    The conversion of cellular prion protein (PrP(C)) into its pathological isoform (PrP(Sc)) conveys an increase in hydrophobicity and induces a partial resistance to proteinase K (PK). Interestingly, co-incubation with high copper ion concentrations also modifies the solubility of PrP(c) and induces a partial PK resistance which was reminiscent of PrP(Sc). However, concerns were raised whether this effect was not due to a copper-induced inhibition of the PK itself. We have therefore analyzed the kinetics of the formation of PK-resistant PrP(C) and excluded possible interference effects by removing unbound copper ions prior to the addition of PK by methanol precipitation or immobilization of PrP(C) followed by washing steps. We found that preincubation of PrPc with copper ions at concentrations as low as 50 microM indeed rendered these proteins completely PK resistant, while control substrates were proteolyzed. No other divalent cations induced a similar effect. However, in addition to this specific stabilizing effect on PrP(C), higher copper ion concentrations in solution (>200 microM) directly blocked the enzymatic activity of PK, possibly by replacing the Ca2+ ions in the active center of the enzyme. Therefore, as a result of this inhibition the proteolytic degradation of PrP(C) as well as PrP(Sc) molecules was suppressed.

  13. Synthesis and characterization of copper ions surface-doped titanium dioxide nanotubes

    SciTech Connect

    Li Haibin Duan Xuechen; Liu Guocong; Li Lili

    2008-08-04

    Copper ions surface-doped titanium dioxide nanotubes were prepared via an assembly process based on the reactions between Cu(NH{sub 2}CH{sub 2}CH{sub 2}NH{sub 2}){sub 2}(OH){sub 2} and hydroxide radicals on the surface of TiO{sub 2} nanotubes, followed by the heat treatment in air at 723 K. The as-prepared samples were characterized with infrared spectroscopy (IR), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), X-ray diffraction (XRD), Raman spectroscopy, and fluorescence spectroscopy (FL). The photocatalytic activity of the copper ions surface-doped titanium dioxide nanotubes was investigated by photodegradation of Rhodamine B. The results showed that copper ions were successfully introduced onto the surface of TiO{sub 2} nanotubes. And two kinds of copper species of Cu(I) and Cu(II) were found on TiO{sub 2} surface. Copper ions act as electron trappers facilitating the separation of electrons and holes on the surface of TiO{sub 2} nanotubes, which allows more efficiency for the photodegradation of Rhodamine B.

  14. SETUP AND PERFORMANCE OF THE RHIC INJECTOR ACCELERATORS FOR THE 2005 RUN WITH COPPER IONS.

    SciTech Connect

    AHRENS, L.; ALESSI, J.; GARDNER, C.J.

    2005-05-16

    Copper ions for the 2005 run [1] of the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory (BNL) are accelerated in the Tandem, Booster and AGS prior to injection into RHIC. The setup and performance of these accelerators with copper are reviewed in this paper.

  15. Copper ions removal from water using functionalized carbon nanotubes–mullite composite as adsorbent

    SciTech Connect

    Tofighy, Maryam Ahmadzadeh; Mohammadi, Toraj

    2015-08-15

    Highlights: • CNTs–mullite composite was prepared via chemical vapor deposition (CVD) method. • The prepared composite was modified with concentrated nitric acid and chitosan. • The modified CNTs–mullite composites were used as novel adsorbents. • Copper ion removal from water by the prepared adsorbents was performed. • Langmuir and Freundlich isotherms and two kinetic models were applied to fit the experimental data. - Abstract: Carbon nanotubes–mullite composite was synthesized by direct growth of carbon nanotubes on mullite particles via chemical vapor deposition method using cyclohexanol and ferrocene as carbon precursor and catalyst, respectively. The carbon nanotubes–mullite composite was oxidized with concentrated nitric acid and functionalized with chitosan and then used as a novel adsorbent for copper ions removal from water. The results demonstrated that modification with concentrated nitric acid and chitosan improves copper ions adsorption capacity of the prepared composite, significantly. Langmuir and Freundlich isotherms and two kinetic models were applied to fit the experimental data. The carbon nanotubes growth on mullite particles to form the carbon nanotubes–mullite composite with further modification is an inherently safe approach for many promising environmental applications to avoid some concerns regarding environment, health and safety. It was found that the modified carbon nanotubes–mullite composite can be considered as an excellent adsorbent for copper ions removal from water.

  16. The Release Behavior of Diamond Shocked to 20 Mbar

    NASA Astrophysics Data System (ADS)

    Gregor, M. C.; McCoy, C. A.; Polsin, D. N.; Boehly, T. R.; Meyerhofer, D. D.; Fratanduono, D. E.; Celliers, P. M.; Collins, G. W.

    2015-11-01

    High-density carbon (HDC) is used as an ablator for inertial confinement fusion experiments at the National Ignition Facility (NIF). Both its Hugoniot and release behaviors are needed for ignition target designs. The OMEGA laser was used to shock HDC to 10 to 20 Mbar; it was then released into materials with known Hugoniots (quartz, CH, silica foam, and liquid deuterium). The impedance-matching technique with these references provides data that constrains the HDC release models. This technique was applied to both the single-crystal diamond and the NIF ablator--ultra-nanocrystalline diamond (UNCD). This study provided the first data for the UNCD Hugoniot and models for the release isentropes of both types of HDC using a Mie-Grüneisen equation of state. This material is based upon work supported by the Department of Energy National Nuclear Security Administration under Award Number DE-NA0001944.

  17. Contact Killing of Bacteria on Copper Is Suppressed if Bacterial-Metal Contact Is Prevented and Is Induced on Iron by Copper Ions

    PubMed Central

    Mathews, Salima; Hans, Michael

    2013-01-01

    Bacteria are rapidly killed on copper surfaces, and copper ions released from the surface have been proposed to play a major role in the killing process. However, it has remained unclear whether contact of the bacteria with the copper surface is also an important factor. Using laser interference lithography, we engineered copper surfaces which were covered with a grid of an inert polymer which prevented contact of the bacteria with the surface. Using Enterococcus hirae as a model organism, we showed that the release of ionic copper from these modified surfaces was not significantly reduced. In contrast, killing of bacteria was strongly attenuated. When E. hirae cells were exposed to a solid iron surface, the loss of cell viability was the same as on glass. However, exposing cells to iron in the presence of 4 mM CuSO4 led to complete killing in 100 min. These experiments suggest that contact killing proceeds by a mechanism whereby the metal-bacterial contact damages the cell envelope, which, in turn, makes the cells susceptible to further damage by copper ions. PMID:23396344

  18. Kinetics and thermodynamics of copper ions removal from wastewater by use of zeolite.

    PubMed

    Panayotova, M I

    2001-01-01

    Natural Bulgarian zeolite was tested for its ability to remove Cu2+ from model wastewater. Influence of process variables was investigated. It was found that the optimum wastewater to zeolite ratio is 100:1 and the optimum pH value of water to be treated is 5.5 to 7.5. Zeolite with finer particles shows a higher uptake capacity. The simultaneous presence of Ca2+ and Mg2+ in concentrations similar to their concentrations in Bulgarian natural water does not significantly influence the uptake of Cu2+. Zeolite modification by treating it with NaCl, CH3COONa and NaOH increases its uptake ability. Copper ions are strongly immobilized by modified zeolite and secondary pollution of water caused by its contact with preloaded zeolite is very low (1.5-2.5% of Cu2+ preliminary immobilized have been released back into acidified water). Contacting with 2 mol dm(-3) NaCl can easily regenerate loaded zeolite; best results were obtained for zeolite modified with NaCl. Requirements of Bulgarian standards for industrial wastewater can be met by a one-stage process for an initial Cu2+ concentration of 10 mg dm(-3), and by a two stage process for an initial Cu2+ concentration of 50 mg dm(-3). Uptake of Cu2+ by zeolite from neutral wastewater has proved to be as effective as Cu2+ removal by precipitation of copper hydroxide. The process of Cu2+ uptake by natural zeolite is best described by the kinetic equation for adsorption. This fact, together with the correlation found between the Cu2+ uptake and the amount of Na+, Ca2+ and K+ released into solution by zeolite shows that the ion exchange sorption plays the basic role in Cu2+ uptake by natural zeolite. The value obtained for the apparent activation energy (26.112 kJ mol(-1) implies that the process can be easily carried out with a satisfactory rate. The uptake equilibrium is best described by the Langmuir adsorption isotherm, with Langmuir constants KL= 6.4 x 10(-2) dm3 mg(-1) and M = 6.74 mg g(-1). The apparent equilibrium constant

  19. Diffuse-interface theory for structure formation and release behavior in controlled drug release systems.

    PubMed

    Saylor, David M; Kim, Chang-Soo; Patwardhan, Dinesh V; Warren, James A

    2007-11-01

    A common method of controlling drug release has been to incorporate the drug into a polymer matrix, thereby creating a diffusion barrier that slows the rate of drug release. It has been demonstrated that the internal microstructure of these drug-polymer composites can significantly impact the drug release rate. However, the effect of processing conditions during manufacture on the composite structure and the subsequent effects on release behavior are not well understood. We have developed a diffuse-interface theory for microstructure evolution that is based on interactions between drug, polymer and solvent species, all of which may be present in either crystalline or amorphous states. Because the theory can be applied to almost any specific combination of material species and over a wide range of environmental conditions, it can be used to elucidate and quantify the relationships between processing, microstructure and release response in controlled drug release systems. Calculations based on the theory have now demonstrated that, for a characteristic delivery system, variations in microstructure arising due to changes in either drug loading or processing time, i.e. evaporation rate, could have a significant impact on both the bulk release kinetics and the uniformity of release across the system. In fact, we observed that changes in process time alone can induce differences in bulk release of almost a factor of two and typical non-uniformities of +/-30% during the initial periods of release. Because these substantial variations may have deleterious clinical ramifications, it is critical that both the system microstructure and the control of that microstructure are considered to ensure the device will be both safe and effective in clinical use.

  20. Copper ion redox state is critical for its effects on ion transport pathways and methaemoglobin formation in trout erythrocytes.

    PubMed

    Bogdanova, Anna Yu; Gassmann, Max; Nikinmaa, Mikko

    2002-01-22

    We have studied the mechanism of copper uptake by the cells, its oxidative action and effects on ion transport systems using rainbow trout erythrocytes. Cupric ions enter trout erythrocytes as negatively charged complexes with chloride and hydroxyl anions via the band 3-mediated Cl-/HCO3- exchanger. Replacement of Cl- by gluconate, and complexation of cupric ions with histidine abolish rapid Cu2+ uptake. Within the cell cupric ions interact with haemoglobin, causing methaemoglobin formation by direct electron transfer from heme Fe2+ to Cu2+, and consecutive proton release. Ascorbate-mediated reduction of cupric ions to cuprous decreases copper-induced metHb formation and proton release. Moreover, cuprous ions stimulate Na+H+ exchange and residual Na+ transport causing net Na+ accumulation in the cells. The effect requires copper binding to an externally facing thiol group. Copper-induced Na+ accumulation is accompanied by K+ loss occurring mainly via K+-Cl- cotransporter. Taurine efflux is also stimulated by copper exposure. However, net loss of osmolytes is not as pronounced as Na+ uptake and modest swelling of the cells occurs after 5 min of copper exposure. Taken together the results indicate that copper toxicity, including copper transport into the cells and its interactions with ion transport processes, depend on the valency and complex formation of copper ions.

  1. Microanalysis of oligodeoxynucleotides by cathodic stripping voltammetry at amalgam-alloy surfaces in the presence of copper ions.

    PubMed

    Hason, Stanislav; Vetterl, Vladimír

    2006-05-15

    The application of gold amalgam-alloy electrode (AuAE) for a sensitive voltammetric detection of different oligodeoxynucleotides (ODNs) containing the purine units within the ODN-chains in the presence of copper is described. The detection of ODNs is based on the following procedure: (i) the first step includes an acidic hydrolysis of the ODN (ahODN) samples performing the release of the purine bases from ODN-chain; (ii) the second step includes an electrochemical accumulation of the complex of the purine base residues released from ODN-chain with copper ions Cu(I) (ahODN-Cu(I) complex) at the potential of reduction of copper ions Cu(II) on the amalgam-alloy electrode surfaces; (iii) finally followed the cathodic stripping of the electrochemically accumulated ahODN-Cu(I) complex from the electrode surface. The proposed electrochemical method was used for: (a) detection of different ODN lengths containing only adenine units (the number of adenine units within the ODN-chains was changed from 10 to 80), and (b) determination of the number of purine units within the 30-mer ODNs containing a random sequence segments involving both the purine and pyrimidine units. The intensity of the cathodic stripping current density peak (j(CSP)) of the electrochemically accumulated ahODN-Cu(I) complex increased linearly with the increasing number of purine units within the ODN-chains. We observed a good correlation between the percentage content of purine units to the whole length of different 30-mer ODNs and the percentage content of the intensity of the j(CSP) of the electrochemically accumulated 30-mer ahODN-Cu(I) complexes. The detection of acid hydrolysed 80-mer (A(80)) in the bulk solution and in a 20-mul volume is possible down to 200pM and 2nM at the AuAE, respectively. For the shortest 10-mer (A(10)) a detectable value of 5nM in the bulk solution on the AuAE was observed. The sensitive detection of different ODNs containing the purine units in their chains in the presence of

  2. Effects of light and copper ions on volatile aldehydes of milk and milk fractions

    SciTech Connect

    Jeno, W.; Bassette, R.; Crang, R.E.

    1988-09-01

    Raw, laboratory-pasteurized and plant-pasteurized homogenized milks were exposed to copper ions (5 ppm), to sunlight or fluorescent light and the effects determined on the composition of volatile aldehydes. The greatest change due to copper treatment was an increase in n-hexanal; acetaldehyde showed the least response in each of the sources of milk. The responses were similar from all three sources of milk with laboratory-pasteurized milk samples showing the greatest responses for each aldehyde analyzed. Similar milk samples exposed to sunlight also showed an increase in volatile aldehydes from all milk sources but with the greatest response being acetaldehyde and n-pentanal components. The milk fraction most susceptible to changes in the presence of light was neutralized whey, whereas resuspended cream was most susceptible to copper exposure. Overall, dialyzed whey appeared to be influenced more than other milk fractions by both light and copper ions.

  3. Detection of copper ions from aqueous solutions using layered double hydroxides thin films deposited by PLD

    NASA Astrophysics Data System (ADS)

    Vlad, A.; Birjega, R.; Matei, A.; Luculescu, C.; Nedelcea, A.; Dinescu, M.; Zavoianu, R.; Pavel, O. D.

    2015-10-01

    Layered double hydroxides (LDHs) thin films with Mg-Al were deposited using pulsed laser deposition (PLD) technique. We studied the ability of our films to detect copper ions in aqueous solutions. Copper is known to be a common pollutant in water, originating from urban and industrial waste. Clay minerals, including layered double hydroxides (LDHs), can reduce the toxicity of such wastes by adsorbing copper. We report on the uptake of copper ions from aqueous solution on LDH thin films obtained via PLD. The obtained thin films were characterized using X-ray Diffraction, Atomic Force Microscopy, and Scanning Electron Microscopy with Energy Dispersive X-ray analysis. The results in this study indicate that LDHs thin films obtained by PLD have potential as an efficient adsorbent for removing copper from aqueous solution.

  4. A Comparative Interaction between Copper Ions with Alzheimer's β Amyloid Peptide and Human Serum Albumin.

    PubMed

    Behbehani, G Rezaei; Barzegar, L; Mohebbian, M; Saboury, A A

    2012-01-01

    The interaction of Cu(2+) with the first 16 residues of the Alzheimer's amyliod β peptide, Aβ(1-16), and human serum albumin (HSA) were studied in vitro by isothermal titration calorimetry at pH 7.2 and 310 K in aqueous solution. The solvation parameters recovered from the extended solvation model indicate that HSA is involved in the transport of copper ion. Complexes between Aβ(1-16) and copper ions have been proposed to be an aberrant interaction in the development of Alzheimer's disease, where Cu(2+) is involved in Aβ(1-16) aggregation. The indexes of stability indicate that HSA removed Cu(2+) from Aβ(1-16), rapidly, decreased Cu-induced aggregation of Aβ(1-16), and reduced the toxicity of Aβ(1-16) + Cu(2+) significantly.

  5. A Comparative Interaction between Copper Ions with Alzheimer's β Amyloid Peptide and Human Serum Albumin

    PubMed Central

    Behbehani, G. Rezaei; Barzegar, L.; Mohebbian, M.; Saboury, A. A.

    2012-01-01

    The interaction of Cu2+ with the first 16 residues of the Alzheimer's amyliod β peptide, Aβ(1–16), and human serum albumin (HSA) were studied in vitro by isothermal titration calorimetry at pH 7.2 and 310 K in aqueous solution. The solvation parameters recovered from the extended solvation model indicate that HSA is involved in the transport of copper ion. Complexes between Aβ(1–16) and copper ions have been proposed to be an aberrant interaction in the development of Alzheimer's disease, where Cu2+ is involved in Aβ(1–16) aggregation. The indexes of stability indicate that HSA removed Cu2+ from Aβ(1–16), rapidly, decreased Cu-induced aggregation of Aβ(1–16), and reduced the toxicity of Aβ(1–16) + Cu2+ significantly. PMID:22844264

  6. EPR and optical absorption studies of copper ions in diglycine calcium chloride tetrahydrate

    NASA Astrophysics Data System (ADS)

    Kripal, Ram; Bajpai, Manisha

    2009-04-01

    EPR study of copper ions in diglycine calcium chloride tetrahydrate (DGCCT), [(NH 2CH 2COOH) 2·CaCl 2·4H 2O] single crystals at room temperature is carried out. The spin Hamiltonian parameters of copper ions are determined as: gx = 2.0238 ± 0.0002, gy = 2.1122 ± 0.0002, gz = 2.2250 ± 0.0002, Ax = (83 ± 2) × 10 -4 cm -1, Ay = (86 ± 2) × 10 -4 cm -1 and Az = (118 ± 2) × 10 -4 cm -1. The optical study of the single crystals at room temperature is also done and the bands are assigned to d-d and charge transfer transitions. Using above data, the nature of bonding in the complex is discussed.

  7. Theoretical analysis of copper-ion extraction through hollow fiber supported liquid membranes

    SciTech Connect

    Shiau, C.Y.; Chen, P.Z. )

    1993-10-01

    An understanding of the extraction of metal ions through hollow fiber supported liquid membranes is important for the design of such systems. In this paper, copper-ion extraction through hollow fiber supported liquid membranes containing D2EHPA as a carrier agent is analyzed. Both a rigorous model and a simple model with varied permeation coefficients for the system are proposed. The once-through mode is first modeled and the parametric effects on the extraction rate are discussed. The recycling mode is then modeled. A comparison between the rigorous model and the simple model with varied/constant permeation coefficients is made. From the models it is found that the permeation coefficient is a function of copper ion concentration. 18 refs., 9 figs., 1 tab.

  8. Copper ion-selective fluorescent sensor based on the inner filter effect using a spiropyran derivative.

    PubMed

    Shao, Na; Zhang, Ying; Cheung, Sinman; Yang, Ronghua; Chan, Winghong; Mo, Tain; Li, Kean; Liu, Feng

    2005-11-15

    A highly selective copper(II) ion fluorescent sensor has been designed based on the UV-visible absorption of a spiropyran derivative coupled with the use of a metal porphyrin operative on the fluorescence inner filter effect. Spiropyrans, which combine the characteristics of metal binding and signal transduction, have been widely utilized in cationic ion recognition by UV-visible spectroscopy. In the present work, the viability of converting the absorption signal of the spiropyran molecule into a fluorescence signal was explored. On account of overlap of the absorption band of the spiropyran (lambda(abs) = 547 nm) in the presence of copper ion with the Q-band of an added fluorophore, zinc meso-tetraphenylporphyrin (lambda(abs) = 556 nm), the effective light absorbed by the porphyrin and concomitantly the emitted light intensity vary as a result of varying absorption of the spiropyran via fluorescence inner filter effect. The metal binding characteristic of the spiropyran presents an excellent selectivity for copper ion in comparison with several other heavy or transition metal ions. Since the changes in the absorbance of the absorber translate into exponential changes in fluorescence of the fluorophore, the novelty of the present device is that the analytical signal is more sensitive over that of the absorptiometry or that of the fluorometry using one single dye. To realize a practical fluorescent sensor, both the absorber and fluorophore were immobilized in a plasticized poly(vinyl chloride) membrane, and the sensing characteristics of the membrane for copper ion were investigated. The sensor is useful for measuring Cu2+ at concentrations ranging from 7.5 x 10(-7) to 3.6 x 10(-5) M with a detection limit of 1.5 x 10(-7) M. The sensor is chemically reversible, the fluorescence was switched off by immersing the membrane in copper ion solution and switched on by washing it with EDTA solution.

  9. Infuence of Microstructure in Drug Release Behavior of Silica Nanocapsules

    PubMed Central

    Zoltan, Tamara

    2013-01-01

    Meso- and nanoporous structures are adequate matrices for controlled drug delivery systems, due to their large surface areas and to their bioactive and biocompatibility properties. Mesoporous materials of type SBA-15, synthesized under different pH conditions, and zeolite beta were studied in order to compare the different intrinsic morphological characteristics as pore size, pore connectivity, and pore geometry on the drug loading and release process. These materials were characterized by X-ray diffraction, nitrogen adsorption, scanning and transmission electron microscopy, and calorimetric measurements. Ibuprofen (IBU) was chosen as a model drug for the formulation of controlled-release dosage forms; it was impregnated into these two types of materials by a soaking procedure during different periods. Drug loading and release studies were followed by UV-Vis spectrophotometry. All nano- and mesostructured materials showed a similar loading behavior. It was found that the pore size and Al content strongly influenced the release process. These results suggest that the framework structure and architecture affect the drug adsorption and release properties of these materials. Both materials offer a good potential for a controlled delivery system of ibuprofen. PMID:23986870

  10. Microwave preparation of raw vermiculite for use in removal of copper ions from aqueous solutions.

    PubMed

    Lee, Taeyoon

    2011-01-01

    This study sought to determine optimum conditions for the microwave exfoliation of raw vermiculite and examined the removal characteristics of copper ions from water by the processed vermiculite. When 100 g of raw vermiculite was irradiated at 440 W for 330 s, 66% of the raw vermiculite was exfoliated. The dry density and specific surface area of the exfoliated vermiculite were 0.28 g/cm3 and 54.6 m2/g, respectively. When considering the dry density (2.78 g/cm3) and specific surface area (11.1 m2/g) of the raw vermiculite, microwave irradiation resulted in an approximate 10 times expansion and a five-fold increase in specific surface area. Serial batch tests were conducted to determine the removal characteristics of the exfoliated vermiculite for copper ions in aqueous solutions. Copper was most effectively removed by exfoliated vermiculite with an initial pH of 5. Exfoliated vermiculite at this pH also produced the highest first-order rate constants and instantaneous partition coefficient. These results indicate that exfoliated vermiculite can be prepared by microwave irradiation instead of conventional heat processes for use as a copper ion adsorbent.

  11. Reduction of microbial pathogens during apple cider production using sodium hypochlorite, copper ion, and sonication.

    PubMed

    Rodgers, Stephanie L; Ryser, Elliot T

    2004-04-01

    Sodium hypochlorite (100 ppm), copper ion water (1 ppm), and sonication (22 to 44 kHz and 44 to 48 kHz) were assessed individually and in combination for their ability to reduce populations of Escherichia coli O157:H7 and Listeria monocytogenes on apples and in apple cider. Commercial unpasteurized cider was inoculated to contain approximately 10(6) CFU/ml of either pathogen and then sonicated at 44 to 48 kHz, with aliquots removed at intervals of 30 to 60 s for up to 5 min and plated to determine numbers of survivors. Subsequently, whole apples were inoculated by dipping to contain approximately 10(6) CFU/g E. coli O157:H7 or L. monocytogenes, held overnight, and then submerged in 1 ppm copper ion water with or without 100 ppm sodium hypochlorite for 3 min with or without sonication at 22 to 44 kHz and examined for survivors. Treated apples were also juiced, with the resulting cider sonicated for 3 min. Populations of both pathogens decreased 1 to 2 log CFU/ml in inoculated cider following 3 min of sonication. Copper ion water alone did not significantly reduce populations of either pathogen on inoculated apples. However, when used in combination with sodium hypochlorite, pathogen levels decreased approximately 2.3 log CFU/g on apples. Sonication of this copper ion-sodium hypochlorite solution at 22 to 44 kHz did not further improve pathogen reduction on apples. Numbers of either pathogen in the juice fraction were approximately 1.2 log CFU/ml lower after being juiced, with sonication (44 to 48 kHz) of the expressed juice decreasing L. monocytogenes and E. coli O157:H7 populations an additional 2 log. Hence, a 5-log reduction was achievable for both pathogens with the use of copper ion water in combination with sodium hypochlorite followed by juicing and sonication at 44 to 48 kHz.

  12. Comparison of acute behavioral effects of sustained-release and immediate-release methylphenidate.

    PubMed

    Kollins, S H; Rush, C R; Pazzaglia, P J; Ali, J A

    1998-11-01

    The rate of onset of a drug's effect is an important determinant of its abuse potential. This experiment examined the acute behavioral effects of orally administered sustained-release methylphenidate (SR; 20-40 mg), immediate-release methylphenidate (IR; 20-40 mg), and placebo in 10 healthy volunteers. Drug effects were assessed before drug administration and periodically afterwards for 6 hr using drug-effect questionnaires and performance measures that are sensitive to the acute effects of stimulants. The IR formulation produced stimulant-like drug effects (e.g., increased ratings of "good effects") that generally varied as a function of dose and time. The SR formulation produced only transient effects on these measures. These findings are consistent with previous research on the influence of rate of onset using other drugs and suggest that the abuse potential of IR methylphenidate may be greater than that of SR methylphenidate.

  13. Tritium release behavior of ceramic breeder candidates for fusion reactors

    NASA Astrophysics Data System (ADS)

    Kudo, H.; Okuno, K.; O'hira, S.

    1988-07-01

    The overall HTO(g) release rates of neutron-irradiated Li 2O, γ-LiAlO 2, Li 2SiO 3, Li 2ZrO 3. and Li 8ZrO 6 crystals were controlled by the diffusion of tritium in the crystals, while solid-surface reactions competed in the release process. The order of tritium diffusivity in these crystals was D(Li 8ZrO 6) > D(Li 2O) > D(Li 2ZrO 3) > D(Li 2SiO 3) > D(γ-LiAlO 2) . In Li 2O crystals irradiated with thermal and 14-MeV neutrons the T - state of tritium was found to exist together with the most abundant T + species (OT -), but no T - species was found in unirradiated crystals in which tritium had been dissolved under thermal equilibrium conditions. Although the thermal release behavior of tritium dissolved in Li 2O crystals resembled that in neutron-irradiated ones, the diffusivity of T + ions in the unirradiated crystal was lower than that in the irradiated crystal. The solubility of tritium gas (HT) in Li 2O crystals obeyed the Sieverts' law.

  14. Environmental behavior of tritium released to the atmosphere in winter

    SciTech Connect

    Davis, P.A.; Cornett, R.J.; Killey, R.W.D.; Wood, M.J.; Workman, W.J.G. . Chalk River Nuclear Labs.)

    1992-03-01

    An accidental release of HTO to the atmosphere from a reactor at the Chalk River Laboratories was assessed in a timely and efficient manner using a combination of predictive modelling and environmental sampling. A simple Gaussian plume model performed well in predicting the concentration of HTO in air. Doses to workers and to members of the public were well below acceptable levels at all times during the incident. This paper reports that the release was turned to advantage to study tritium behavior in the winter environment. HT concentrations were measured in aid, falling snow, vegetation and the snowpack at many locations during and after the release. The rate of HTO deposition to snow is greatly enhanced when snow is falling. The rate of new snow accumulation exceeded the rate of HTO diffusion in snow, so that the snowpack retained essentially all of the tritium deposited to it until spring melt occurred. Snow core data were therefore used as a surrogate for air concentrations to study the dispersion of the airborne plume, which was strongly affected by the topography of the Ottawa River Valley.

  15. Polyglycerol-Based Copper Chelators for the Transport and Release of Copper Ions in Biological Environments.

    PubMed

    Albrecht, Ralf; Fehse, Susanne; Pant, Kritee; Nowag, Sabrina; Stephan, Holger; Haag, Rainer; Tzschucke, Carl Christoph

    2016-03-01

    Here, the synthesis and characterization of three improved nanosystems is presented based on amino functionalized hyperbranched polyglycerol (hPG; M(w) = 16.8 kDa) as potential copper(II) chelators. The ligands, N-methyl-N-picolylglycine amide, 2,6-pyridine dicarboxylic acid monoamide, and cyclam tetraacetic acid (TETA) monoamide, are covalently attached to the polymer with amide bonds. In this paper, the Cu(II) loading capacity, the stability of the Cu(II)-loaded carriers at different pHs, with competing ligands and in human serum, as well as the transport of Cu(II) in biological systems are investigated. For the first time, a different cytotoxicity of functionalized polymer nanoparticles with and without Cu(II) is observed. The cyclam-based carrier combines the highest loading capacity (29 Cu ions/nanoparticle), best stability with respect to pH and EDTA (45% remaining Cu after 24 h), lowest cytotoxicity (IC50 > 100 × 10(-6) M (unloaded), 1500 × 10(-6) M Cu(II); Cu:carrier 29:1), and the highest stability in human serum.

  16. Cancer Therapy by Catechins Involves Redox Cycling of Copper Ions and Generation of Reactive Oxygen species.

    PubMed

    Farhan, Mohd; Khan, Husain Yar; Oves, Mohammad; Al-Harrasi, Ahmed; Rehmani, Nida; Arif, Hussain; Hadi, Sheikh Mumtaz; Ahmad, Aamir

    2016-02-04

    Catechins, the dietary phytochemicals present in green tea and other beverages, are considered to be potent inducers of apoptosis and cytotoxicity to cancer cells. While it is believed that the antioxidant properties of catechins and related dietary agents may contribute to lowering the risk of cancer induction by impeding oxidative injury to DNA, these properties cannot account for apoptosis induction and chemotherapeutic observations. Catechin (C), epicatechin (EC), epigallocatechin (EGC) and epigallocatechin-3-gallate (EGCG) are the four major constituents of green tea. In this article, using human peripheral lymphocytes and comet assay, we show that C, EC, EGC and EGCG cause cellular DNA breakage and can alternatively switch to a prooxidant action in the presence of transition metals such as copper. The cellular DNA breakage was found to be significantly enhanced in the presence of copper ions. Catechins were found to be effective in providing protection against oxidative stress induced by tertbutylhydroperoxide, as measured by oxidative DNA breakage in lymphocytes. The prooxidant action of catechins involved production of hydroxyl radicals through redox recycling of copper ions. We also determined that catechins, particularly EGCG, inhibit proliferation of breast cancer cell line MDA-MB-231 leading to a prooxidant cell death. Since it is well established that tissue, cellular and serum copper levels are considerably elevated in various malignancies, cancer cells would be more subject to redox cycling between copper ions and catechins to generate reactive oxygen species (ROS) responsible for DNA breakage. Such a copper dependent prooxidant cytotoxic mechanism better explains the anticancer activity and preferential cytotoxicity of dietary phytochemicals against cancer cells.

  17. Cancer Therapy by Catechins Involves Redox Cycling of Copper Ions and Generation of Reactive Oxygen Species

    PubMed Central

    Farhan, Mohd; Khan, Husain Yar; Oves, Mohammad; Al-Harrasi, Ahmed; Rehmani, Nida; Arif, Hussain; Hadi, Sheikh Mumtaz; Ahmad, Aamir

    2016-01-01

    Catechins, the dietary phytochemicals present in green tea and other beverages, are considered to be potent inducers of apoptosis and cytotoxicity to cancer cells. While it is believed that the antioxidant properties of catechins and related dietary agents may contribute to lowering the risk of cancer induction by impeding oxidative injury to DNA, these properties cannot account for apoptosis induction and chemotherapeutic observations. Catechin (C), epicatechin (EC), epigallocatechin (EGC) and epigallocatechin-3-gallate (EGCG) are the four major constituents of green tea. In this article, using human peripheral lymphocytes and comet assay, we show that C, EC, EGC and EGCG cause cellular DNA breakage and can alternatively switch to a prooxidant action in the presence of transition metals such as copper. The cellular DNA breakage was found to be significantly enhanced in the presence of copper ions. Catechins were found to be effective in providing protection against oxidative stress induced by tertbutylhydroperoxide, as measured by oxidative DNA breakage in lymphocytes. The prooxidant action of catechins involved production of hydroxyl radicals through redox recycling of copper ions. We also determined that catechins, particularly EGCG, inhibit proliferation of breast cancer cell line MDA-MB-231 leading to a prooxidant cell death. Since it is well established that tissue, cellular and serum copper levels are considerably elevated in various malignancies, cancer cells would be more subject to redox cycling between copper ions and catechins to generate reactive oxygen species (ROS) responsible for DNA breakage. Such a copper dependent prooxidant cytotoxic mechanism better explains the anticancer activity and preferential cytotoxicity of dietary phytochemicals against cancer cells. PMID:26861392

  18. Removal of copper ions from aqueous solution by the sodium salt of the maleic acid-allylpropionate-styrene terpolymer.

    PubMed

    Akperov, Elchin; Akperov, Oktay; Jafarova, Elnara; Gafarova, Sabahiye

    2016-09-01

    The sodium salt of the maleic acid-allylpropionate-styrene terpolymer was used for recovery of copper ions from aqueous solution. Effects of contact time, sorbent weight and initial Cu(2+) ion concentrations on removal efficiency were tested. The maximum experimental sorption capacity of the sorbent for copper ions is 0.71 g g(-1). The sorption isotherm of copper ions onto a prepared polymer sorbent has been studied and the equilibrium data were analyzed using Langmuir and Freundlich isotherm models. The adsorption isotherm data showed that copper ions adsorption on the sorbent was better fitted to the Langmuir isotherm model. The Lagergren pseudo-first- and pseudo-second-order kinetic models were applied to examine the kinetics of the copper ions sorption by the synthesized sorbent. The kinetic data are best described by the pseudo-second-order model. The calculated value of the maximum sorption capacity by the pseudo-second-order equation (0.62 g g(-1)) corresponds well with its experimentally found value (0.71 g g(-1)). Considering the obtained kinetic data, and the Fourier transform infrared spectroscopy (FT-IR) and UV-vis spectra of the sorbent after the sorption, it is possible to come to the conclusion that during the sorption process Cu(2+) ions enter a complex with the carboxylic groups of the maleic acid units of the sorbent.

  19. Metallic copper corrosion rates, moisture content, and growth medium influence survival of copper ion-resistant bacteria.

    PubMed

    Elguindi, Jutta; Moffitt, Stuart; Hasman, Henrik; Andrade, Cassandra; Raghavan, Srini; Rensing, Christopher

    2011-03-01

    The rapid killing of various bacteria in contact with metallic copper is thought to be influenced by the influx of copper ions into the cells, but the exact mechanism is not fully understood. This study showed that the kinetics of contact killing of copper surfaces depended greatly on the amount of moisture present, copper content of alloys, type of medium used, and type of bacteria. We examined antibiotic- and copper ion-resistant strains of Escherichia coli and Enterococcus faecium isolated from pig farms following the use of copper sulfate as feed supplement. The results showed rapid killing of both copper ion-resistant E. coli and E. faecium strains when samples in rich medium were spread in a thin, moist layer on copper alloys with 85% or greater copper content. E. coli strains were rapidly killed under dry conditions, while E. faecium strains were less affected. Electroplated copper surface corrosion rates were determined from electrochemical polarization tests using the Stern-Geary method and revealed decreased corrosion rates with benzotriazole and thermal oxide coating. Copper ion-resistant E. coli and E. faecium cells suspended in 0.8% NaCl showed prolonged survival rates on electroplated copper surfaces with benzotriazole coating and thermal oxide coating compared to surfaces without anti-corrosion treatment. Control of surface corrosion affected the level of copper ion influx into bacterial cells, which contributed directly to bacterial killing.

  20. Sorption of cadmium and copper ions on natural and synthetic hydroxylapatite particles

    SciTech Connect

    Fernane, F.; Mecherri, M.O.; Sharrock, P. Hadioui, M.; Lounici, H.; Fedoroff, M.

    2008-05-15

    The sorption of divalent cadmium and copper ions from aqueous solutions on natural and synthetic hydroxyapatite was investigated by the batch method and under dynamic conditions in columns at 22 deg. C and pH 5. The effect of cadmium and copper concentration on sorption was studied. Both types of apatites are efficient, despite their different composition and morphology. The sorption mechanism involves an ion exchange for Cd(II), while Cu(II) leads to precipitation of a newly formed solid. Thus, the sorption efficiency depends on the experimental conditions and the specific physicochemical properties of the apatites used. The sorption isotherms were fitted to the Langmuir equation.

  1. A new thio-Schiff base fluorophore with copper ion sensing, DNA binding and nuclease activity.

    PubMed

    Vikneswaran, R; Syafiq, Muhamad Syamir; Eltayeb, Naser Eltaher; Kamaruddin, Mohd Naqiuddin; Ramesh, S; Yahya, R

    2015-01-01

    Copper ion recognition and DNA interaction of a newly synthesized fluorescent Schiff base (HPyETSC) were investigated using UV-vis and fluorescent spectroscopy. Examination using these two techniques revealed that the detection of copper by HPyETSC is highly sensitive and selective, with a detection limit of 0.39 μm and the mode of interaction between HPyETSC and DNA is electrostatic, with a binding constant of 8.97×10(4) M(-1). Furthermore, gel electrophoresis studies showed that HPyETSC exhibited nuclease activity through oxidative pathway.

  2. Kinetics of copper ion absorption by cross-linked calcium polyacrylate membranes

    NASA Technical Reports Server (NTRS)

    Philipp, W. H.; May, C. E.

    1983-01-01

    The absorption of copper ions from aqueous copper acetate solutions by cross-linked calcium acrylate membranes was found to obey parabolic kinetics similar to that found for oxidation of metals that form protective oxide layers. For pure calcium polyacrylate membranes the rate constant was essentially independent of copper acetate concentration and film thickness. For a cross-linked copolymer film of polyvinyl alcohol and calcium polyacrylate, the rate constant was much greater and dependent on the concentration of copper acetate. The proposed mechanism in each case involves the formation of a copper polyacrylate phase on the surface of the membrane. The diffusion of the copper ion through this phase appears to be the rate controlling step for the copolymer film. The diffusion of the calcium ion is apparently the rate controlling step for the calcium polyacrylate. At low pH, the copper polyacrylate phase consists of the normal copper salt; at higher pH, the phase appears to be the basic copper salt.

  3. Dispersive liquid-liquid microextraction of copper ions as neocuproine complex in environmental aqueous samples.

    PubMed

    Shariati, Shahab; Golshekan, Mostafa

    2011-06-01

    In the present study, a simple and efficient extraction method based on dispersive liquid-liquid microextraction prior to UV-Vis spectrophotometry was developed for the preconcentration and determination of copper ions in environmental samples. Briefly, cupric ions (Cu II) were reduced to cuprous (Cu I) with addition of hydroxyl amine hydrochloride and formed hydrophobic chelates with neocuproine. Then, a proper mixture of acetonitrile (as dispersive solvent) and choloroform (as extraction solvent) was rapidly injected into the solution and a cloudy solution was formed. After centrifuging, choloroform was sedimented at the bottom of a conical tube and diluted with 100 µL of methanol for further UV-Vis spectrophotometry measurement. An orthogonal array design (OAD) was employed to study the effects of different parameters on the extraction efficiency. Under the optimum experimental conditions, a preconcentration factor up to 63.6 was achieved for extraction from 5.0 mL of sample solution. The limit of detection (LOD) based on S/N = 3 was 0.33 µg L-1 and the calibration curve was linear in the range of 1-200 µg L-1 with reasonable linearity (r2 > 0.997). Finally, the accuracy of the proposed method was successfully evaluated by determination of trace amounts of copper ions in different water samples and satisfactory results were obtained.

  4. New biosensor for detection of copper ions in water based on immobilized genetically modified yeast cells.

    PubMed

    Vopálenská, Irena; Váchová, Libuše; Palková, Zdena

    2015-10-15

    Contamination of water by heavy metals represents a potential risk for both aquatic and terrestrial organisms, including humans. Heavy metals in water resources can come from various industrial activities, and drinking water can be ex-post contaminated by heavy metals such as Cu(2+) from house fittings (e.g., water reservoirs) and pipes. Here, we present a new copper biosensor capable of detecting copper ions at concentrations of 1-100 μM. This biosensor is based on cells of a specifically modified Saccharomyces cerevisiae strain immobilized in alginate beads. Depending on the concentration of copper, the biosensor beads change color from white, when copper is present in concentrations below the detection limit, to pink or red based on the increase in copper concentration. The biosensor was successfully tested in the determination of copper concentrations in real samples of water contaminated with copper ions. In contrast to analytical methods or other biosensors based on fluorescent proteins, the newly designed biosensor does not require specific equipment and allows the quick detection of copper in many parallel samples.

  5. Incorporation of copper ions into crystals of T2 copper-depleted laccase from Botrytis aclada

    SciTech Connect

    Osipov, E. M.; Polyakov, K. M.; Tikhonova, T. V.; Kittl, R.; Dorovatovskii, P.V.; Shleev, S. V.; Popov, V. O.; Ludwig, R.

    2015-11-18

    The restoration of the native form of laccase from B. aclada from the type 2 copper-depleted form of the enzyme was investigated. Copper ions were found to be incorporated into the active site after soaking the depleted enzyme in a Cu{sup +}-containing solution. Laccases belong to the class of multicopper oxidases catalyzing the oxidation of phenols accompanied by the reduction of molecular oxygen to water without the formation of hydrogen peroxide. The activity of laccases depends on the number of Cu atoms per enzyme molecule. The structure of type 2 copper-depleted laccase from Botrytis aclada has been solved previously. With the aim of obtaining the structure of the native form of the enzyme, crystals of the depleted laccase were soaked in Cu{sup +}- and Cu{sup 2+}-containing solutions. Copper ions were found to be incorporated into the active site only when Cu{sup +} was used. A comparative analysis of the native and depleted forms of the enzymes was performed.

  6. Electrochemical determination of copper ions in spirit drinks using carbon paste electrode modified with biochar.

    PubMed

    Oliveira, Paulo Roberto; Lamy-Mendes, Alyne C; Rezende, Edivaltrys Inayve Pissinati; Mangrich, Antonio Sálvio; Marcolino, Luiz Humberto; Bergamini, Márcio F

    2015-03-15

    This work describes for first time the use of biochar as electrode modifier in combination with differential pulse adsorptive stripping voltammetric (DPAdSV) techniques for preconcentration and determination of copper (II) ions in spirit drinks samples (Cachaça, Vodka, Gin and Tequila). Using the best set of the experimental conditions a linear response for copper ions in the concentration range of 1.5 × 10(-6) to 3.1 × 10(-5) mol L(-1) with a Limit of Detection (LOD) of 4.0 × 10(-7) mol L(-1). The repeatability of the proposed sensor using the same electrode surface was measured as 3.6% and 6.6% using different electrodes. The effect of foreign species on the voltammetric response was also evaluated. Determination of copper ions content in different samples of spirit drinks samples was also realized adopting inductively coupled plasma optical emission spectroscopy (ICP-OES) and the results achieved are in agreement at a 95% of confidence level.

  7. Activation of oxygen-mediating pathway using copper ions: fine-tuning of growth kinetics in gold nanorod overgrowth.

    PubMed

    Liu, Wenqi; Zhang, Hui; Wen, Tao; Yan, Jiao; Hou, Shuai; Shi, Xiaowei; Hu, Zhijian; Ji, Yinglu; Wu, Xiaochun

    2014-10-21

    Growth kinetics plays an important role in the shape control of nanocrystals (NCs). Herein, we presented a unique way to fine-tune the growth kinetics via oxidative etching activated by copper ions. For the overgrowth of gold nanorods (Au NRs), competitive adsorption of dissolved oxygen on rod surface was found to slow down the overgrowth rate. Copper ions were able to remove the adsorbed oxygen species from the Au surface via oxidative etching, thus exposing more reaction sites for Au deposition. In this way, copper ions facilitated the overgrowth process. Furthermore, Cu(2+) rather than Cu(+) acted as the catalyst for the oxidative etching. Comparative study with Ag(+) indicated that Cu(2+) cannot regulate NC shapes via an underpotential deposition mechanism. In contrast, Ag(+) led to the formation of Au tetrahexahedra (THH) and a slight decrease of the growth rate at similar growth conditions. Combining the distinct roles of the two ions enabled elongated THH to be produced. Copper ions activating the O2 pathway suggested that dissolved oxygen has a strong affinity for the Au surface. Moreover, the results of NC-sensitized singlet oxygen ((1)O2) indicated that the absorbed oxygen species on the surface of Au NCs bounded with low-index facets mainly existed in the form of molecular O2.

  8. Copper ion fluxes through the floating water bridge under strong electric potential.

    PubMed

    Giuliani, Livio; D'Emilia, Enrico; Lisi, Antonella; Grimaldi, Settimio; Brizhik, Larissa; Del Giudice, Emilio

    2015-01-01

    We have performed a series of experiments applying high voltage between two electrodes, immersed in two beakers containing bidistilled water in a way similar to experiments conducted by Fuchs and collaborators, which showed that a water bridge can be formed between the two containers. We also observed the formation of water bridge. Moreover, choosing different pairs of electrodes depending on the material they are made up of, we observed that copper ions flow can pass along the bridge if the negative electrode is made up of copper. We show that the direction of the flux not only depends on the applied electrostatic field but on the relative electronegativity of the electrodes too. These results open new perspectives in understanding the properties of water. We suggest a possible explanation of the obtained results.

  9. Biocompatible D-Penicillamine Conjugated Au Nanoparticles: Targeting Intracellular Free Copper Ions for Detoxification

    PubMed Central

    Kandanapitiye, Murthi S.; Gunathilake, Chamila; Jaroniec, Mietek

    2015-01-01

    High thiophillicicity of the Au-nanoparticle (Au NP) surface leads to covalent attachment of D-penicillamine molecules to Au NPs to form biocompatible D-penicillamine conjugated Au NPs. The latter are highly water-dispersible, exhibit no cytotoxicity, and can readily penetrate the cell membrane to target intracellular free copper ions for selective copper detoxification in the presence of the other divalent essential metal ions including Zn(II), Fe(II), Mn(II), Ca(II), and Mg(II), thus opening up a new avenue for improving the efficacy and pharmacokinetics of D-penicillamine, an important clinical drug currently used to treat the copper overload-related diseases and disorders. PMID:26213624

  10. Copper ions interfere with the reduction of the water-soluble tetrazolium salt-8.

    PubMed

    Semisch, Annetta; Hartwig, Andrea

    2014-02-17

    Metabolic activity as a measure of cell viability is frequently determined using the water-soluble tetrazolium salt 2-(2-methoxy-4-nitrophenyl)-3-(4-nitrophenyl)-5-(2,4-disulfophenyl)-2H-tetrazolium monosodium salt (WST-8), commercially available as CCK-8 reagent. In this study, CCK-8 was investigated with respect to its suitability for investigating nano- and microscale copper oxide (CuO NP and CuO MP) as well as water-soluble copper chloride (CuCl2). The results were compared to cell number and colony forming ability. Our data demonstrate that the CCK-8 assay overestimates the loss of metabolic activity by CuCl2 and CuO NP, because of interference by copper ions with the reduction of the dye.

  11. Contribution of Copper Ion Resistance to Survival of Escherichia coli on Metallic Copper Surfaces▿

    PubMed Central

    Santo, Christophe Espírito; Taudte, Nadine; Nies, Dietrich H.; Grass, Gregor

    2008-01-01

    Bacterial contamination of touch surfaces poses a serious threat for public health. The use of bactericidal surface materials, such as copper and its alloys, might constitute a way to aid the use of antibiotics and disinfectants, thus minimizing the risk of emergence and spread of multiresistant germs. The survival of Escherichia coli on metallic copper surfaces has been studied previously; however, the mechanisms underlying bacterial inactivation on copper surfaces have not been elucidated. Data presented in this study suggest that bacteria are killed rapidly on dry copper surfaces. Several factors, such as copper ion toxicity, copper chelators, cold, osmotic stress, and reactive oxygen species, but not anaerobiosis, influenced killing rates. Strains deleted in copper detoxification systems were slightly more sensitive than was the wild type. Preadaptation to copper enhanced survival rates upon copper surface exposure. This study constitutes a first step toward understanding the reasons for metallic copper surface-mediated killing of bacteria. PMID:18156321

  12. Copper ions stimulate the proliferation of hepatic stellate cells via oxygen stress in vitro.

    PubMed

    Xu, San-qing; Zhu, Hui-yun; Lin, Jian-guo; Su, Tang-feng; Liu, Yan; Luo, Xiao-ping

    2013-02-01

    This study examined the effect of copper ions on the proliferation of hepatic stellate cells (HSCs) and the role of oxidative stress in this process in order to gain insight into the mechanism of hepatic fibrosis in Wilson's disease. LX-2 cells, a cell line of human HSCs, were cultured in vitro and treated with different agents including copper sulfate, N-acetyl cysteine (NAC) and buthionine sulfoximine (BSO) for different time. The proliferation of LX-2 cells was measured by non-radioactive cell proliferation assay. Real-time PCR and Western blotting were used to detect the mRNA and protein expression of platelet-derived growth factor receptor β subunit (PDGFβR), ELISA to determine the level of glutathione (GSH) and oxidized glutathione (GSSG), dichlorofluorescein assay to measure the level of reactive oxygen species (ROS), and lipid hydroperoxide assay to quantify the level of lipid peroxide (LPO). The results showed that copper sulfate over a certain concentration range could promote the proliferation of LX-2 cells in a time- and dose-dependent manner. The effect was most manifest when LX-2 cells were treated with copper sulfate at a concentration of 100 μmol/L for 24 h. Additionally, copper sulfate could dose-dependently increase the levels of ROS and LPO, and decrease the ratio of GSH/GSSG in LX-2 cells. The copper-induced increase in mRNA and protein expression of PDGFβR was significantly inhibited in LX-2 cells pre-treated with NAC, a precursor of GSH, and this phenomenon could be reversed by the intervention of BSO, an inhibitor of NAC. It was concluded that copper ions may directly stimulate the proliferation of HSCs via oxidative stress. Anti-oxidative stress therapies may help suppress the copper-induced activation and proliferation of HSCs.

  13. Comparative time-courses of copper-ion-mediated protein and lipid oxidation in low-density lipoprotein.

    PubMed

    Knott, Heather M; Baoutina, Anna; Davies, Michael J; Dean, Roger T

    2002-04-15

    Free radicals damage both lipids and proteins and evidence has accumulated for the presence of both oxidised lipids and proteins in aged tissue samples as well as those from a variety of pathologies including atherosclerosis, diabetes, and Parkinson's disease. Oxidation of the protein and lipid moieties of low-density lipoprotein is of particular interest due to its potential role in the unregulated uptake of lipids and cholesterol by macrophages; this may contribute to the initial stage of foam cell formation in atherosclerosis. In the study reported here, we examined the comparative time-courses of lipid and protein oxidation during copper-ion-mediated oxidation of low-density lipoprotein. We show that there is an early, lipid-mediated loss of 40-50% of the Trp residues of the apoB100 protein. There is no comparable loss over an identical period during the copper-ion-mediated oxidation of lipid-free BSA. Concomitant with Trp loss, the antioxidant alpha-tocopherol is consumed with subsequent extensive lipid peroxidation. Further changes to the protein, including the copper-ion-dependent 3.5-fold increase in 3,4-dihydroxyphenylalanine and the copper-ion-independent 3-5-fold increase in o-tyrosine, oxidation products of Tyr and Phe, respectively, only occur after maximal lipid peroxidation. Long incubation periods result in depletion of 3,4-dihydroxyphenylalanine, presumably reflecting further oxidative changes. Overall, copper-ion-mediated oxidation of LDL appears to proceed initially by lipid radical-dependent processes, even though some of the earliest detectable changes occur on the apoB100 protein. This is followed by extensive lipid peroxidation and subsequent additional oxidation of aromatic residues on apoB100, though it is not yet clear whether this late protein oxidation is lipid-dependent or occurs as a result of direct radical attack.

  14. Phycoremediation and adsorption isotherms of cadmium and copper ions by Merismopedia tenuissima and their effect on growth and metabolism.

    PubMed

    Fawzy, Mustafa A

    2016-09-01

    The current study tends to investigate the removal of cadmium and copper ions by Merismopedia tenuissima, grown in different concentrations of cadmium and copper ions, as well to investigate their effects on growth and metabolism. Sorption isotherms of Langmuir and Freundlich were obtained for the quantitative description of cadmium and copper uptake by M. tenuissima. Langmuir model adequately to describe the data of biosorption for these metals. However, the Freundlich model could work well in case of Cu(2+) only. M. tenuissima appears to be more efficient for removing Cd(2+) ions than Cu(2+). However, the affinity constant of Cu(2+) on the biomass of M. tenuissima was higher than Cd(2+) indicating that M. tenuissima is more tolerant to Cd(2+) phytotoxicity than Cu(2+). FTIR analysis of algae with and without biosorption revealed the presence of carboxyl, amino, amide and hydroxyl groups, which were responsible for biosorption of Cd(+2) and Cu(+2) ions.

  15. Polyacrylamide hydrogel encapsulated E. coli expressing metal-sensing green fluorescent protein as a potential tool for copper ion determination

    PubMed Central

    Tantimongcolwat, Tanawut; Isarankura-Na-Ayudhya, Chartchalerm; Srisarin, Apapan; Galla, Hans-Joachim; Prachayasittikul, Virapong

    2014-01-01

    A simple, inexpensive and field applicable metal determination system would be a powerful tool for the efficient control of metal ion contamination in various sources e.g. drinking-water, water reservoir and waste discharges. In this study, we developed a cell-based metal sensor for specific and real-time detection of copper ions. E. coli expressing metal-sensing green fluorescent protein (designated as TG1/(CG)6GFP and TG1/H6CdBP4GFP) were constructed and served as a metal analytical system. Copper ions were found to exert a fluorescence quenching effect, while zinc and cadmium ions caused minor fluorescence enhancement in the engineered bacterial suspension. To construct a user-friendly and reagentless metal detection system, TG1/H6CdBP4GFP and TG1/(CG)6GFP were encapsulated in polyacrylamide hydrogels that were subsequently immobilized on an optical fiber equipped with a fluorescence detection module. The sensor could be applied to measure metal ions by simply dipping the encapsulated bacteria into a metal solution and monitoring fluorescence changes in real time as a function of the metal concentration in solution. The sensor system demonstrated high specificity toward copper ions. The fluorescence intensities of the encapsulated TG1/(CG)6GFP and TG1/H6CdBP4GFP were quenched by approximately 70 % and 80 % by a high-dose of copper ions (50 mM), respectively. The level of fluorescence quenching exhibited a direct correlation with the copper concentration, with a linear correlation coefficient (r) of 0.99. The cell-based metal sensor was able to efficiently monitor copper concentrations ranging between 5 M and 50 mM, encompassing the maximum allowed copper contamination in drinking water (31.15 M) established by the WHO. Furthermore, the cell-based metal sensor could undergo prolonged storage for at least 2 weeks without significantly influencing the copper sensitivity. PMID:26417267

  16. Efficient ratiometric fluorescence probe based on dual-emission quantum dots hybrid for on-site determination of copper ions.

    PubMed

    Yao, Jianlei; Zhang, Kui; Zhu, Houjuan; Ma, Fang; Sun, Mingtai; Yu, Huan; Sun, Jian; Wang, Suhua

    2013-07-02

    Of various chemosensory protocols, the color change observed by the naked eye is considered to be a conceivable and on-site way to indicate the presence of an analyte. We herein designed a ratiometric fluorescence probe by hybridizing dual-emission quantum dots (QDs) and demonstrated its efficiency for on-site visual determination of copper ions. The hybrid probe comprises two sizes of cadmium telluride QDs emitting red and green fluorescence, respectively, in which the red-emitting ones are embedded in silica nanoparticles and the green-emitting ones are covalently linked onto the surface. The fluorescence of the embedded QDs is insensitive to the analyte, whereas the green emissive QDs are functionalized to be selectively quenched by the analyte. Upon exposure to different amounts of copper ions, the variations of the dual emission intensity ratios display continuous color changes from green to red, which can be clearly observed by the naked eye. The limit of detection for copper is estimated to be 1.1 nM, much lower than the allowable level of copper (~20 μM) in drinking water set by U.S. Environmental Protection Agency. The probe is demonstrated for the determination of copper ions in lake water and mineral water samples, especially for visually monitoring copper residues on herb leaves. This prototype ratiometric probe is simple, fully self-contained, and thus potentially attractive for visual identification without the need for elaborate equipment.

  17. The effect of copper ions on the lipid composition of subcellular membranes in Hydrilla verticillata.

    PubMed

    Rozentsvet, Olga A; Nesterov, Viktor N; Sinyutina, Natalia F

    2012-09-01

    The paper studies changes in the content and composition of lipids in the membranes of chloroplasts, mitochondria and microsomes of the aquatic plant Hydrilla verticillata exposed to copper ions (100 μM; 1, 3, 6 and 24 h). The rate of copper accumulation and the coefficient of its extraction by the plant were also determined. The presence of copper in the incubation medium and its accumulation in the plant tissues decreased the content of photosynthetic pigments, stimulated lipid peroxidation and enhanced membrane permeability. The gradual accumulation of copper in the plant tissues was accompanied by specific changes in the composition of lipids: the content of sulfolipids (SQDG) in chloroplasts declined; the content of monogalactosyl diacylglycerols (MGDG), digalactosyl diacylglycerols (DGDG) and phosphatidyl glycerols (PG) in chloroplasts and mitochondria grew after an hour of copper exposure; and the content of all the lipids except phosphatidic acids (PA) decreased after 3 h of exposure. The decline in the content of phosphatidyl cholines (PC) was first observed in the membranes of microsomes (after an hour of exposure) and later in the membranes of chloroplasts and mitochondria (after 3-6 h of exposure). The experiments with incorporation of [2-(14)C]sodium acetate into fatty acids of polar lipids showed that in parallel with lipid destruction, there took place an intensive and specific renewal of the lipid pool of subcellular membrane fractions.

  18. Removal of copper ions from aqueous solution by adlai shell (Coix lacryma-jobi L.) adsorbents.

    PubMed

    de Luna, Mark Daniel G; Flores, Edgar D; Cenia, Marie Chela B; Lu, Ming-Chun

    2015-09-01

    Adlai shell (Coix lacryma-jobi L.) adsorbents (ASA) were used to remove copper ions from aqueous solutions under batch conditions. The effect of physical and chemical modification of ASA on Cu(II) removal was evaluated. Results showed that the high coefficients of determination for the pseudo-second order (R(2) > 0.9999) and for the intraparticle diffusion (R(2) > 0.9843) equations indicate that the rate-determining step is a combination of pore diffusion and chemisorption at low Cu(II) concentration and boundary layer, pore diffusion and chemisorption at high Cu(II) concentration. At 298K and 100 mg L(-1) Cu(II), the computed qe and k2 values were 17.2 mg g(-1) and 0.012 g mg(-1) min(-1), respectively. The Freundlich model (R(2) > 0.9636) adequately describes the experimental data indicating heterogeneous adsorption. Overall, the results of the study demonstrate the potential of adlai shell adsorbents for the removal of heavy metals from aqueous solutions.

  19. Estimation of free copper ion concentrations in blood serum using T1 relaxation rates

    NASA Astrophysics Data System (ADS)

    Blicharska, Barbara; Witek, Magdalena; Fornal, Maria; MacKay, Alex L.

    2008-09-01

    The water proton relaxation rate constant R1 = 1/ T1 (at 60 MHz) of blood serum is substantially increased by the presence of free Cu 2+ ions at concentrations above normal physiological levels. Addition of chelating agents to serum containing paramagnetic Cu 2+ nulls this effect. This was demonstrated by looking at the effect of adding a chelating agent—D-penicillamine (D-PEN) to CuSO 4 and CuCl 2 aqueous solutions as well as to rabbit blood serum. We propose that the measurement of water proton spin-lattice relaxation rate constants before and after chelation may be used as an alternative approach for monitoring the presence of free copper ions in blood serum. This method may be used in the diagnosis of some diseases (leukaemia, liver diseases and particularly Wilson's disease) because, in contrast to conventional methods like spectrophotometry which records the total number of both bound and free ions, the proton relaxation technique is sensitive solely to free paramagnetic ions dissolved in blood serum. The change in R1 upon chelation was found to be less than 0.06 s -1 for serum from healthy subjects but greater than 0.06 s -1 for serum from untreated Wilson's patients.

  20. Sensitive detection of copper ions via ion-responsive fluorescence quenching of engineered porous silicon nanoparticles

    NASA Astrophysics Data System (ADS)

    Hwang, Jangsun; Hwang, Mintai P.; Choi, Moonhyun; Seo, Youngmin; Jo, Yeonho; Son, Jaewoo; Hong, Jinkee; Choi, Jonghoon

    2016-10-01

    Heavy metal pollution has been a problem since the advent of modern transportation, which despite efforts to curb emissions, continues to play a critical role in environmental pollution. Copper ions (Cu2+), in particular, are one of the more prevalent metals that have widespread detrimental ramifications. From this perspective, a simple and inexpensive method of detecting Cu2+ at the micromolar level would be highly desirable. In this study, we use porous silicon nanoparticles (NPs), obtained via anodic etching of Si wafers, as a basis for undecylenic acid (UDA)- or acrylic acid (AA)-mediated hydrosilylation. The resulting alkyl-terminated porous silicon nanoparticles (APS NPs) have enhanced fluorescence stability and intensity, and importantly, exhibit [Cu2+]-dependent quenching of fluorescence. After determining various aqueous sensing conditions for Cu2+, we demonstrate the use of APS NPs in two separate applications – a standard well-based paper kit and a portable layer-by-layer stick kit. Collectively, we demonstrate the potential of APS NPs in sensors for the effective detection of Cu2+.

  1. Sensitive detection of copper ions via ion-responsive fluorescence quenching of engineered porous silicon nanoparticles

    PubMed Central

    Hwang, Jangsun; Hwang, Mintai P.; Choi, Moonhyun; Seo, Youngmin; Jo, Yeonho; Son, Jaewoo; Hong, Jinkee; Choi, Jonghoon

    2016-01-01

    Heavy metal pollution has been a problem since the advent of modern transportation, which despite efforts to curb emissions, continues to play a critical role in environmental pollution. Copper ions (Cu2+), in particular, are one of the more prevalent metals that have widespread detrimental ramifications. From this perspective, a simple and inexpensive method of detecting Cu2+ at the micromolar level would be highly desirable. In this study, we use porous silicon nanoparticles (NPs), obtained via anodic etching of Si wafers, as a basis for undecylenic acid (UDA)- or acrylic acid (AA)-mediated hydrosilylation. The resulting alkyl-terminated porous silicon nanoparticles (APS NPs) have enhanced fluorescence stability and intensity, and importantly, exhibit [Cu2+]-dependent quenching of fluorescence. After determining various aqueous sensing conditions for Cu2+, we demonstrate the use of APS NPs in two separate applications – a standard well-based paper kit and a portable layer-by-layer stick kit. Collectively, we demonstrate the potential of APS NPs in sensors for the effective detection of Cu2+. PMID:27752120

  2. Simultaneous Platinum and Copper Ion Attachment to a Human Copper Chaperone Protein

    NASA Astrophysics Data System (ADS)

    Hodak, Miroslav; Cvitkovic, John; Yu, Corey; Dmitriev, Oleg; Kaminski, George; Bernholc, Jerry

    2015-03-01

    Cisplatin is a potent anti-cancer drug based on a platinum ion. However, its effectiveness is decreased by cellular resistance, which involves cisplatin attaching to copper transport proteins. One of such proteins is Atox1, where cisplatin attaches to the copper binding site. Surprisingly, it was shown that both cisplatin and copper can attach to Atox1 at the same time. To study this double metal ion attachment, we use the KS/FD DFT method, which combines Kohn-Sham DFT with frozen-density DFT to achieve efficient quantum-mechanical description of explicit solvent. Calculations have so far investigated copper ion attachment to CXXC motifs present in Atox1. The addition of the platinum ion and the competition between the two metals is currently being studied. These calculations start from a molecular mechanics (MM) structural model, in which glutathione groups provide additional ligands to the Pt ion. Our goals are to identify possible Cu-Pt structures and to determine whether copper/platinum attachment is competitive, independent, or cooperative. Results will be compared to the 1H, N1 5 -HSQC NMR experiments, in which binding of copper and cisplatin to Atox1 produces distinct secondary chemical shift signatures, allowing for kinetic studies of simultaneous metal binding.

  3. Behavioral profiles of the captive juvenile whooping crane as an indicator of post-release survival

    USGS Publications Warehouse

    Kreger, M.D.; Hatfield, J.S.; Estevez, I.; Gee, G.F.; Clugston, D.A.

    2006-01-01

    Predation by bobcats (Lynx rufus) is the major cause of mortality in captive-reared whooping cranes (Grus americana) released into the wild to establish a nonmigratory flock in Florida. This study investigated whether rearing methods (parent-rearing, hand-rearing, or hand-rearing with exercise) of cranes, and behaviors observed in birds either before or shortly after release in the wild, are associated with survival after release. Rearing methods did not affect survival first year post-release, which was 55 ? 8% in 2 yr (1999 and 2000). Logistic regression revealed, however, that foraging bouts (+), walking bouts (-), and body weight (-) before release, and nonvigilant bouts (-) after release were significantly associated with survival. These results suggest that post-release survival of whooping cranes might be increased by rearing techniques that promote foraging.

  4. Intra-molecular G-quadruplex structure generated by DNA-templated click chemistry: "turn-on" fluorescent probe for copper ions.

    PubMed

    Shen, Qinpeng; Zhou, Lifen; Yuan, Yijia; Huang, Yan; Xiang, Binbin; Chen, Chunyan; Nie, Zhou; Yao, Shouzhuo

    2014-05-15

    A novel homogenous fluorescent sensor for signal-on detection of Cu(2+) has been developed based on intra-molecular G-quadruplex formed by DNA-templated click reaction and crystal violet (CV) as label-free signal reporter. The clickable DNA probe consists of two G-rich strands (A and B) bearing azide and alkyne group, respectively, and a template strand (C) locating two proximate reactants by pairing with A and B. The sequences of A and B are derived from asymmetric split of the G-quadruplex sequence (TTAGGG)4. In the presence of Cu(2+), the whole G-quadruplex sequence A-B is generated by chemical ligation of A and B via copper ion-catalyzed alkyne-azide cycloaddition, then released from template by toehold strand displacement, and consequently forming a stable intra-molecular G-quadruplex, which binds with CV to generate a strong fluorescent signal. Oppositely, weak fluorescence was obtained without Cu(2+) because of unstable intermolecular G-quadruplex formed by A and B and lack of lateral loop connection. Therefore, the Cu(2+) can be sensitively and specifically detected by the fluorescence of the CV-stained G-quadruplex with a low detection limit of 65nM and a linear range of 0.1-3µM. This method rationally integrated the DNA-templated synthesis and G-quadruplex structure-switch, presenting a simple and promising approach for biosensor development.

  5. The effects of captive rearing on the behavior of newly-released whooping cranes (Grus americana)

    USGS Publications Warehouse

    Kreger, M.D.; Hatfield, J.S.; Estevez, I.; Gee, G.F.; Clugston, D.A.

    2005-01-01

    Rearing treatments used in captivity to prepare animals for reintroduction to the wild may have a profound effect on behavior and, possibly, affect their survival after reintroduction. This study examined the behaviors of captive-reared whooping cranes (Grus americana) upon their release in Florida to determine if rearing treatments may affect the behavior of the birds and how these affect their chances of survival in the wild. Individually tagged birds were observed at the rearing facility, the U.S. Geological Survey Patuxent Wildlife Research Center in Maryland, from hatch to 20 weeks of age and at the release site in Central Florida for up to 6 weeks post release. The rearing treatments were parent reared (PR), hand reared (HR), and hand reared with exercise (HRE). Observations at the rearing facility are described in a previous paper. At the release site, each bird was observed for 5 min every morning (0700?1000 h) and late afternoon (1500?1800 h) during the 6-week study period. Our results indicated that most of the time, the n = 34 birds were foraging (46.03 ? 1.48%), followed by nonvigilant (20.89 ? 0.73%), vigilant (19.21 ? 0.72%), or performing comfort behaviors (11.61 ? 1.28%). Data were analyzed using mixed models repeated measures ANOVA. There were no significant behavioral differences between HR and HRE birds. PR birds were found in larger groups than HR birds during the first 2 weeks post release and greater than HR and HRE birds afterwards. This may be interpreted as an antipredator strategy for birds that relied on parental guidance during rearing. HR and HRE birds foraged more than PR birds during the first 2 weeks post release and PR birds were more vigilant during the first 2 weeks post release. Across rearing treatments, the percentages of time spent foraging and engaged in vigilant behaviors during rearing were positively correlated with their behavior upon release. If any of these behaviors can be demonstrated to have relevance for the

  6. Analysis of fission product release behavior during the TMI-2 accident

    SciTech Connect

    Petti, D. A.; Adams, J. P.; Anderson, J. L.; Hobbins, R. R.

    1987-01-01

    An analysis of fission product release during the Three Mile Island Unit 2 (TMI-2) accident has been initiated to provide an understanding of fission product behavior that is consistent with both the best estimate accident scenario and fission product results from the ongoing sample acquisition and examination efforts. ''First principles'' fission product release models are used to describe release from intact, disrupted, and molten fuel. Conclusions relating to fission product release, transport, and chemical form are drawn. 35 refs., 12 figs., 7 tabs.

  7. Study of coagulation processes of selected humic acids under copper ions influence*

    NASA Astrophysics Data System (ADS)

    Boguta, Patrycja; Sokolowska, Zofia

    2013-04-01

    Humic acids have limited sorption capacity and big dose of metal or other mineral component which can be sorbed on humic acids, can cause saturation of negative, surface charge of humic acids leading to destabilization of dissolved humic acids compounds. Destabilisation can be observed as coagulation and floculation proces of humic acids. However there are a lot of mechanisms which causing precipitation of humic acids. Thereby, in order to full description of coagulation process, different methods should be applied. Ordinarily, humic acids coagulation is studied by measurement of absorbance, transmittance or carbon loss in solution. Meanwhile, very significant information is also variation of metal content in soil solution and information whether metal goes to precipitate together with humic acids or stays in dissolved form in solution. So, that, from one side, processes of stronger accumulation of metal can lead to soil degradation and micronutrient deficiency for plants. However, there is also possibility to stay metal in solution in toxic and bioavailable form for plants. Main aim of this paper was to study coagulation process of different humic acids extracted from mucking peats under copper ions influence at adjusted pH to 5. In order to this, four peaty-muck soils were taken from selected places in east part of Poland (meadows and river valleys). These soils differed by humification degree, secondary transformation, density and pH. At next step, humic acids were extracted from soils using sodium hydroxide (NaOH) extractant. After exact purification by washing with HF-HCl mixture and water, humic acids were liofilized. Solutions of humic acids were prepared at concentration 40 mg/dm3 with addition of different amount of copper ions to obtain final concentration of Cu(II) ranged from 0-40mg/dm3. After 24 hours solutions were investigated using measurements of absorbance at 470nm (UV-VIS spectrometer Jasco V-530), measurements of organic carbon in solution

  8. Minimizing nitrous oxide in biological nutrient removal from municipal wastewater by controlling copper ion concentrations.

    PubMed

    Zhu, Xiaoyu; Chen, Yinguang; Chen, Hong; Li, Xiang; Peng, Yongzhen; Wang, Shuying

    2013-02-01

    In this study, nitrous oxide (N(2)O) production during biological nutrient removal (BNR) from municipal wastewater was reported to be remarkably reduced by controlling copper ion (Cu(2+)) concentration. Firstly, it was observed that the addition of Cu(2+) (10-100 μg/L) reduced N(2)O generation by 54.5-73.2 % and improved total nitrogen removal when synthetic wastewater was treated in an anaerobic-aerobic (with low dissolved oxygen) BNR process. Then, the roles of Cu(2+) were investigated. The activities of nitrite and nitrous oxide reductases were increased by Cu(2+) addition, which accelerated the bio-reductions of both nitrite to nitric oxide (NO (2) (-)  → NO) and nitrous oxide to nitrogen gas (N(2)O → N(2)). The quantitative real-time polymerase chain reaction assay indicated that Cu(2+) addition increased the number of N(2)O reducing denitrifiers. Further investigation showed that more polyhydoxyalkanoates were utilized in the Cu(2+)-added system for denitrification. Finally, the feasibility of reducing N(2)O generation by controlling Cu(2+) was examined in two other BNR processes treating real municipal wastewater. As the Cu(2+) in municipal wastewater is usually below 10 μg/L, according to this study, the supplement of influent Cu(2+) to a concentration of 10-100 μg/L is beneficial to reduce N(2)O emission and improve nitrogen removal when sludge concentration in the BNR system is around 3,200 mg/L.

  9. Evolution of the optical releasers for aggressive behavior in cave-dwelling Astyanax fasciatus (Teleostei, Characidae).

    PubMed

    Langecker, T G; Neumann, B; Hausberg, C; Parzefall, J

    1995-07-01

    Epigean and blind cave-dwelling populations of the characid Astyanax fasciatus differ in their agonistic behavior. Epigean specimens are characterized by intense aggressive behavior and territoriality in the laboratory, whereas the blind cave fishes are rarely aggressive and have totally lost the territorial behavior. These behavioral changes are genetically based. In the present study, a comparative analysis of the optical releasers for aggressive behavior has been performed in both epigean and cave-dwelling populations. It was expected that the regression of aggressive behavior should be accompanied by the regression of the genetically fixed optical releasers for aggression in the cave specimens. For the analysis of cave fishes, well-eyed F1-hybrids of cave and epigean specimens (Pachon × Teapao) as well as phylogenetically young cave specimens (Micos) selected for large eyes, have been used. In epigean specimens, aggression is most intensely released by a combination of the signals 'natural shape' and 'locomotion'. The cave populations exhibit a partial regression of the releaser 'natural shape'. 'Locomotion', however, has become a more effective releaser for aggression in cave fishes than it has in their epigean relatives. The results are discussed with respect to their evolutionary significance.

  10. Influence of copper ions on the viability and cytotoxicity of Pseudomonas aeruginosa under conditions relevant to drinking water environments.

    PubMed

    Dwidjosiswojo, Zenyta; Richard, Jessica; Moritz, Miriam M; Dopp, Elke; Flemming, Hans-Curt; Wingender, Jost

    2011-11-01

    Copper plumbing materials can be the source of copper ions in drinking water supplies. The aim of the current study was to investigate the influence of copper ions on the viability and cytotoxicity of the potential pathogen Pseudomonas aeruginosa that presents a health hazard when occurring in building plumbing systems. In batch experiments, exposure of P. aeruginosa (10(6)cells/mL) for 24h at 20°C to copper-containing drinking water from domestic plumbing systems resulted in a loss of culturability, while total cell numbers determined microscopically did not decrease. Addition of the chelator diethyldithiocarbamate (DDTC) to copper-containing water prevented the loss of culturability. When suspended in deionized water with added copper sulfate (10 μM), the culturability of P. aeruginosa decreased by more than 6 log units, while total cell counts, the concentration of cells with intact cytoplasmic membranes, determined with the LIVE/DEAD BacLight kit, and the number of cells with intact 16S ribosomal RNA, determined by fluorescent in situ hybridization, remained unchanged. When the chelator DDTC was added to copper-stressed bacteria, complete restoration of culturability was observed to occur within 14 d. Copper-stressed bacteria were not cytotoxic towards Chinese hamster ovary (CHO-9) cells, while untreated and resuscitated bacteria caused an almost complete decrease of the concentration of viable CHO-9 cells within 24 h. Thus, copper ions in concentrations relevant to drinking water in plumbing systems seem to induce a viable but non-culturable (VBNC) state in P. aeruginosa accompanied by a loss of culturability and cytotoxicity, and VBNC cells can regain both culturability and cytotoxicity, when copper stress is abolished.

  11. [Study on the orientation of liquid crystals presented on the glass substrates spin-coated and functionalized with copper ions].

    PubMed

    Wang, Shiming; Xiong, Xingliang; Zhang, Yan; Li, Guang; Chen, Mengmeng

    2013-06-01

    A stable, uniform, easily implemented, LC-based chemical and biological sensor substrate for orientations of liquid crystals (LCs) for a long-term is urgently needed for medical applications of the sensors. We proposed a use of spin-coating of copper perchlorate (Cu(ClO4)2), with five different concentrations(0-100mmol/L), directly on glass slides for fabricating a layer of chemically-sensitive copper ions. Observing the transmitted light with a polarized microscope, we found the luminosity of the light propagated through sensors deposited with copper ions started to weaken gradually after a certain time. The higher was the concentration of copper ions covered on the glass substrates of the sensors, the faster the weakening occurred, and the less time was needed for transmitted light to turn completely dark. But there was no change in luminosity of the transmitted light for the sensors without Cu(ClO4)2 spin-coating even after stored at room temperature (25 degrees C) for a whole day. When the Cu(ClO4)2 deposited sensors were stored within a drying oven at room temperature (25 degrees C) for 2 months, it was found that there vas almost no change in luminosity of the transmitted lights. The results showed that all the thin films of LC on glass slides functionalized with Cu(ClO4)2 could keep homeotropic and stable orientation for a long time; the concentration of Cu (ClO4)2I has an influence on the orientation response speed of LC from planar to perpendicular orientation.

  12. Sorption of diuron, atrazine, and copper ion on chars with long-term natural oxidation in soils

    NASA Astrophysics Data System (ADS)

    Cheng, C.; Lin, T.; Lai, C.

    2011-12-01

    Biochar has been proposed as a measure to sequestrate carbon (C) and to increase soil fertility in sustainable agriculture. However, its sorption characteristics to herbicides, such as lowing herbicides efficacy, may constrain its agricultural application. This assertion may be arguable because most studies so far were conducted with the newly produced char and barely considered the "ageing effect" of old char since it could be oxidized over long time. In this study, historical char samples were collected and compared with the newly produced char. Batch sorption studies of diuron, atrazine, and copper ion onto chars was performed. Greater sorption of Cu was observed on the historical char samples and reached a saturated sorption at 30 mg g-1 for Cu, much higher adsorption value than newly produced char at 4 mg g-1. In contrast, sorption of diuron and atrazine on newly produced char had the highest sorption capacity than the historical char samples. The historical chars also had much higher negative charge than the newly produced char, but its surface area were lower than the new char. The results indicated that change in surface functional groups through natural oxidation rather than the change of surface area may have more pronounced influences on sorption characteristics, in which the negative charge on the historical chars' surface could hinder the adsorption of diuron and atrazine while enhance the sorption to copper ion. Biological assay to test the toxicity of diuron and copper ion for both historical and new chars on rye seed were conducted and will be presented in our poster.

  13. Reflexive Testosterone Release: A Model System for Studying the Nongenomic Effects of Testosterone Upon Male Behavior

    PubMed Central

    Nyby, John G.

    2008-01-01

    Male mammals of many species exhibit reflexive testosterone release in mating situations. In house mice (Mus musculus), the dramatic robustness of such release, occurring primarily in response to a novel female, suggests some function. The resulting testosterone elevations typically peak during copulatory behavior and may serve to activate transitory motivational and physiological responses that facilitate reproduction. However, such a function requires that testosterone be working through either nongenomic, or very quick genomic, mechanisms. The first part of the review describes reflexive sex hormone release in house mice. The second part summarizes research implicating testosterone’s fast actions in affecting anxiety, reward, learning, analgesia, and penile reflexes in rodents, all of which could optimize male mating success. The review concludes with a speculative model of how spontaneous and reflexive hormone release might interact to regulate reproductive behavior and why mice appear to be an ideal species for examining testosterone’s quick effects. PMID:17976710

  14. Differential response of olfactory sensory neuron populations to copper ion exposure in zebrafish.

    PubMed

    Lazzari, Maurizio; Bettini, Simone; Milani, Liliana; Maurizii, Maria Gabriella; Franceschini, Valeria

    2017-02-01

    The peripheral olfactory system of fish is in direct contact with the external aqueous environment, so dissolved contaminants can easily impair sensory functions and cause neurobehavioral injuries. The olfactory epithelium of fish is arranged in lamellae forming a rosette in the olfactory cavity and contains three main types of olfactory sensory neurons (OSNs): ciliated (cOSNs) and microvillous olfactory sensory neurons (mOSNs), common to all vertebrates, and a third minor group of olfactory neurons, crypt cells, absent in tetrapods. Since copper is a ubiquitously diffusing olfactory toxicant and a spreading contaminant in urban runoff, we investigated the effect of low copper concentration on the three different OSNs in the olfactory epithelium of zebrafish, a model system widely used in biological research. Image analysis was applied for morphometry and quantification of immunohistochemically detected OSNs. Copper exposure resulted in an evident decrease in olfactory epithelium thickness. Moreover, after exposure, the lamellae of the dorsal and ventral halves of the olfactory rosettes showed a different increase in their sensory areas, suggesting a lateral migration of new cells into non-sensory regions. The results of the present study provide clear evidence of a differential response of the three neural cell populations of zebrafish olfactory mucosa after 96h of exposure to copper ions at the sublethal concentration of 30μgL(-1). Densitometric values of cONS, immunostained with anti-G αolf, decreased of about 60% compared to the control. When the fish were transferred to water without copper addition and examined after 3, 10 and 30days, we observed a partial restoration of anti-G αolf staining intensity to normal condition. The recovery of cOSNs appeared sustained by neuronal proliferation, quantified with anti-PCNA immunostaining, in particular in the early days after exposure. The densitometric analysis applied to mOSNs, immunostained with anti-TRPC2

  15. Agarwood Inhibits Histamine Release from Rat Mast Cells and Reduces Scratching Behavior in Mice

    PubMed Central

    Inoue, Eiji; Shimizu, Yasuharu; Masui, Ryo; Tsubonoya, Tomoe; Hayakawa, Tomomi; Sudoh, Keiichi

    2016-01-01

    Objectives: This study was conducted to clarify the effects of agarwood on histamine release from mast cells in rats and on the scratching behaviors in mice. Methods: Histamine release from rat mast cells induced by compound 48/80 or concanavalin A (Con A) and compound 48/80-induced scratching behavior in mice were examined to investigate the effects of agarwood. The hyaluronidase activity and the 3’,5’-cyclic adenosine monophosphate (cAMP) levels in mast cells were examined to investigate the mechanisms for the inhibition of histamine release. The correlation between the inhibitory effects of agarwood on histamine release and the content of its typical ingredients, a 2-(2-phenylethyl)chromone derivatives, was analyzed using thin-layer chromatography. Results: Agarwood showed an inhibitory effect on mast-cell histamine release induced by compound 48/80 or Con A without any effect on hyaluronidase activity; this effect involves an increase in the cAMP levels in mast cells. Oral administration of agarwood showed an inhibitory effect on compound 48/80-induced scratching behavior in mice. The inhibitory effects of agarwood on histamine release were quite different, depending on the area where the agarwood was produced, its quality, and its market price. No correlation was found between the inhibitory effects of agarwood on histamine release and the typical ingredients of agarwood, which are 2-(2-phenylethyl)chromone derivatives. Conclusion: These results show that agarwood inhibits histamine release from mast cells partially through an increase in the cAMP levels in cells. We suggest that some active ingredients of agarwood must be effective on oral intake and that agarwood can be used to treat patients with a number of conditions, including urticaria, atopic dermatitis, and bronchial asthma, in which an increase in histamine release occurs. Differences in the pharmacological effects of this crude drug among markets may provide important information for the quality

  16. Americium and plutonium release behavior from irradiated mixed oxide fuel during heating

    NASA Astrophysics Data System (ADS)

    Sato, I.; Suto, M.; Miwa, S.; Hirosawa, T.; Koyama, S.

    2013-06-01

    The release behavior of Pu and Am was investigated under the reducing atmosphere expected in sodium cooled fast reactor severe accidents. Irradiated Pu and U mixed oxide fuels were heated at maximum temperatures of 2773 K and 3273 K. EPMA, γ-ray spectrometry and α-ray spectrometry for released and residual materials revealed that Pu and Am can be released more easily than U under the reducing atmosphere. The respective release rate coefficients for Pu and Am were obtained as 3.11 × 10-4 min-1 and 1.60 × 10-4 min-1 at 2773 K under the reducing atmosphere with oxygen partial pressure less than 0.02 Pa. Results of thermochemical calculations indicated that the main released chemical forms would likely be PuO for Pu and Am for Am under quite low oxygen partial pressure.

  17. Controlled release behaviors of chitosan/α, β-glycerophosphate thermo-sensitive hydrogels

    NASA Astrophysics Data System (ADS)

    Liu, Wei-Fang; Kang, Chuan-Zhen; Kong, Ming; Li, Yang; Su, Jing; Yi, An; Cheng, Xiao-Jie; Chen, Xi-Guang

    2012-09-01

    Chitosan/α, β-glycerophosphate (CS/α, β-GP) thermo-sensitive hydrogels presented flowable solution state at low temperature and semisolid hydrogel when the ambient temperature increased. In this research, different concentrations of metronidazole encapsulated, CS and α, β-GP, as well as different acid solvents, were chosen to evaluate their influences on the drug release behaviors from CS/α, β-GP hydrogels. It was found that there was a sustaining release during the first 3 h followed by a plateau. SEM images showed that drugs were located both on the surface and in the interior of hydrogels. The optimal preparation conditions of this hydrogel for drug release were as follows: 1.8% (w/v) CS in HAc solvent, 5.6% (w/v) α, β-GP and 5 g/L metronidazole encapsulation. Cytotoxicity evaluation found no toxic effect. In order to control the release rate, 2.5 g/L chitosan microspheres with spherical shape and smooth surface were incorporated, and it was found that the initial release process was alleviated, while drug concentration had no obvious effect on the release rate. It could be concluded that the metronidzole release behaviors could be optimized according to practical applications.

  18. Dynamic Duos? Jamaican Fruit Bats (Artibeus jamaicensis) Do Not Show Prosocial Behavior in a Release Paradigm

    PubMed Central

    Hoffmaster, Eric; Vonk, Jennifer

    2016-01-01

    Once thought to be uniquely human, prosocial behavior has been observed in a number of species, including vampire bats that engage in costly food-sharing. Another social chiropteran, Jamaican fruit bats (Artibeus jamaicensis), have been observed to engage in cooperative mate guarding, and thus might be expected to display prosocial behavior as well. However, frugivory and hematophagy diets may impose different selection pressures on prosocial preferences, given that prosocial preferences may depend upon cognitive abilities selected by different ecological constraints. Thus, we assessed whether Jamaican fruit bats would assist a conspecific in an escape paradigm in which a donor could opt to release a recipient from an enclosure. The test apparatus contained two compartments—one of which was equipped with a sensor that, once triggered, released the trap door of the adjacent compartment. Sixty-six exhaustive pairs of 12 bats were tested, with each bat in each role, twice when the recipient was present and twice when absent. Bats decreased their behavior of releasing the trapdoor in both conditions over time, decreasing the behavior slightly more rapidly in the recipient absent condition. Bats did not release the door more often when recipients were present, regardless of the recipient; thus, there was no clear evidence of prosocial behavior. PMID:27879623

  19. Dynamic Duos? Jamaican Fruit Bats (Artibeus jamaicensis) Do Not Show Prosocial Behavior in a Release Paradigm.

    PubMed

    Hoffmaster, Eric; Vonk, Jennifer

    2016-11-20

    Once thought to be uniquely human, prosocial behavior has been observed in a number of species, including vampire bats that engage in costly food-sharing. Another social chiropteran, Jamaican fruit bats (Artibeus jamaicensis), have been observed to engage in cooperative mate guarding, and thus might be expected to display prosocial behavior as well. However, frugivory and hematophagy diets may impose different selection pressures on prosocial preferences, given that prosocial preferences may depend upon cognitive abilities selected by different ecological constraints. Thus, we assessed whether Jamaican fruit bats would assist a conspecific in an escape paradigm in which a donor could opt to release a recipient from an enclosure. The test apparatus contained two compartments-one of which was equipped with a sensor that, once triggered, released the trap door of the adjacent compartment. Sixty-six exhaustive pairs of 12 bats were tested, with each bat in each role, twice when the recipient was present and twice when absent. Bats decreased their behavior of releasing the trapdoor in both conditions over time, decreasing the behavior slightly more rapidly in the recipient absent condition. Bats did not release the door more often when recipients were present, regardless of the recipient; thus, there was no clear evidence of prosocial behavior.

  20. Drug release behavior of chitosan-montmorillonite nanocomposite hydrogels following electrostimulation.

    PubMed

    Liu, Kun-Ho; Liu, Ting-Yu; Chen, San-Yuan; Liu, Dean-Mo

    2008-07-01

    Nanocomposites hydrogel (nanohydrogel) composed of chitosan (CS) and montmorillonite (MMT) were prepared and systematically studied for drug release behavior following electrostimulation. The deterioration of the responsiveness and reversibility of CS upon repeated on-off electrostimulation switching operations are major limitations for clinical applications, as it suffers from too much structural instability for the precise control of the release of drug upon cyclic electrostimulation. To overcome these limitations, an inorganic phase, MMT, was incorporated in the CS matrix to enhance the anti-fatigue property and corresponding long-term stable release kinetics. X-ray diffraction analysis and time-dependent optical absorbance showed that the MMT incorporated into the nanohydrogel exhibited an exfoliated nanostructure. The exfoliated silica nanosheets are able to act as cross-linkers to form a network structure between the CS and MMT, and this difference in the cross-linking density strongly affects the release of vitamin B(12) under electrostimulation. With a lower MMT concentration (1 wt.%), the release kinetics of vitamin B(12) from the nanohydrogel shows a pseudo-zero-order release, and the release mechanism was changed from a diffusion-controlled mode to a swelling-controlled mode under electrostimulation. Further increasing the MMT content reduced both the diffusion exponent n and the responsiveness of the nanohydrogel to electrostimulation. In addition, a consecutively repeated "on" and "off" operation shows that the electroresponsiveness of the nanohydrogel with higher MMT concentrations was reduced, but its anti-fatigue behavior was considerably improved. In this work, the nanohydrogel with 2 wt.% MMT achieved a mechanically reliable and practically desirable pulsatile release profile and excellent anti-fatigue behavior, compared with that of the pure CS.

  1. Behavioral pattern analysis and dopamine release in quinpirole-induced repetitive behavior in rats.

    PubMed

    de Haas, Ria; Nijdam, Annelies; Westra, Tjalke A; Kas, Martien J H; Westenberg, Herman G M

    2011-12-01

    Obsessive-compulsive disorder (OCD) is a chronic and disabling psychiatric disease with a lifetime prevalence of 2-3%. People with OCD suffer from intrusive, unwanted and recurrent thoughts (obsessions) and/or repetitive ritualistic behaviors (compulsions). The aim of this study is to quantify the dimensions of ritualistic 'compulsive-like' behavior in quinpirole-induced behavior in rats by using T-pattern behavioral analysis. In addition, we investigated whether the behavioral effects elicited by quinpirole sensitization remained after 2 weeks of cessation of treatment. Finally, to study the neurobiological underpinnings of this 'compulsive-like' behavior, we investigated the effect of quinpirole treatment on the extracellular dopamine levels in the nucleus accumbens. Once established, 'compulsive-like' behavior is dependent upon quinpirole administration, as this behavior rapidly normalized after cessation of treatment. After a single dose of quinpirole the dopamine level decreased more in saline pre-treated animals as compared with animals given quinpirole treatment continuously. Furthermore, T-pattern analysis revealed that quinpirole-induced behavior consists, unlike OCD rituals, of a smaller behavioral repertoire. As seen in patients with OCD, quinpirole-treated animals performed these behaviors with a high rate of repetition. These findings suggest that quinpirole-induced behavior mimics only part of the compulsive behavior as shown in OCD patients.

  2. A new approach to copper ion removal from water by polymeric nanocomposite membrane embedded with γ-alumina nanoparticles

    NASA Astrophysics Data System (ADS)

    Ghaemi, Negin

    2016-02-01

    The ability of alumina (Al2O3) nanoparticles in adsorption of heavy metals was employed in improving the copper removal efficiency of PES membranes. Mixed matrix membranes were prepared using PES and different amounts of alumina nanoparticles by phase inversion method. The fabricated membranes were characterized in terms of morphology and performance using scanning electron microscopy (SEM) and atomic force microscopy (AFM) analyses, water contact angle and porosity measurements, determination of pure water flux, copper ion removal, and reusability test. Mixed matrix membranes revealed higher water permeation compared with the pristine PES membrane just by adding small amounts of nanoparticles (≤ 1.0 wt. %) as a result of increasing the membrane porosity and hydrophilicity after addition of alumina nanoparticles into the membrane matrix. Moreover, copper ion removal efficiency of alumina mixed membranes was improved. Membrane performance tests as well as adsorptive nature of alumina nanoparticles proposed that adsorption was the most possible separation mechanism by mixed matrix membranes. Reusability test of membrane confirmed the durability of removal efficiency even after four cycles of filtration.

  3. A sensitive and selective colorimetric method for detection of copper ions based on anti-aggregation of unmodified gold nanoparticles.

    PubMed

    Hormozi-Nezhad, M Reza; Abbasi-Moayed, Samira

    2014-11-01

    A highly sensitive and selective colorimetric method for detection of copper ions, based on anti-aggregation of D-penicillamine (D-PC) induced aggregated gold nanoparticles (AuNPs) was developed. Copper ions can hinder the aggregation of AuNPs induced by D-PC, through formation of mixed-valence complex with D-PC that is a selective copper chelator. In the presence of a fixed amount of D-PC, the aggregation of AuNPs decreases with increasing concentrations of Cu(2+) along with a color change from blue to red in AuNPs solution and an increase in the absorption ratio (A520/A650). Under the optimum experimental conditions (pH 7, [AuNPs] =3.0 nmol L(-1) and [NaCl]=25 mmol L(-1)), a linear calibration curve for Cu(2+) was obtained within the range of 0.05-1.85 µmol L(-1) with a limit of detection (3Sb) of 30 nmol L(-1). Excellent selectivity toward Cu(2+) was observed among various metal ions due to a specific complex formation between Cu(2+) and D-PC. The proposed method has been successfully applied for the detection of Cu(2+) in various real samples.

  4. Enhancing electrical conductivity and electron field emission properties of ultrananocrystalline diamond films by copper ion implantation and annealing

    SciTech Connect

    Sankaran, K. J.; Tai, N. H. E-mail: inanlin@mail.tku.edu.tw; Panda, K.; Sundaravel, B.; Lin, I. N. E-mail: inanlin@mail.tku.edu.tw

    2014-02-14

    Copper ion implantation and subsequent annealing at 600 °C achieved high electrical conductivity of 95.0 (Ωcm){sup −1} for ultrananocrystalline diamond (UNCD) films with carrier concentration of 2.8 × 10{sup 18} cm{sup −2} and mobility of 6.8 × 10{sup 2} cm{sup 2}/V s. Transmission electron microscopy examinations reveal that the implanted Cu ions first formed Cu nanoclusters in UNCD films, which induced the formation of nanographitic grain boundary phases during annealing process. From current imaging tunneling spectroscopy and local current-voltage curves of scanning tunneling spectroscopic measurements, it is observed that the electrons are dominantly emitted from the grain boundaries. Consequently, the nanographitic phases presence in the grain boundaries formed conduction channels for efficient electron transport, ensuing in excellent electron field emission (EFE) properties for copper ion implanted/annealed UNCD films with low turn-on field of 4.80 V/μm and high EFE current density of 3.60 mA/cm{sup 2} at an applied field of 8.0 V/μm.

  5. Copper Ion from Cu2O Crystal Induces AMPK-Mediated Autophagy via Superoxide in Endothelial Cells

    PubMed Central

    Seo, Youngsik; Cho, Young-Sik; Huh, Young-Duk; Park, Heonyong

    2016-01-01

    Copper is an essential element required for a variety of functions exerted by cuproproteins. An alteration of the copper level is associated with multiple pathological conditions including chronic ischemia, atherosclerosis and cancers. Therefore, copper homeostasis, maintained by a combination of two copper ions (Cu+ and Cu2+), is critical for health. However, less is known about which of the two copper ions is more toxic or functional in endothelial cells. Cubic-shaped Cu2O and CuO crystals were prepared to test the role of the two different ions, Cu+ and Cu2+, respectively. The Cu2O crystal was found to have an effect on cell death in endothelial cells whereas CuO had no effect. The Cu2O crystals appeared to induce p62 degradation, LC3 processing and an elevation of LC3 puncta, important processes for autophagy, but had no effect on apoptosis and necrosis. Cu2O crystals promote endothelial cell death via autophagy, elevate the level of reactive oxygen species such as superoxide and nitric oxide, and subsequently activate AMP-activated protein kinase (AMPK) through superoxide rather than nitric oxide. Consistently, the AMPK inhibitor Compound C was found to inhibit Cu2O-induced AMPK activation, p62 degradation, and LC3 processing. This study provides insight on the pathophysiologic function of Cu+ ions in the vascular system, where Cu+ induces autophagy while Cu2+ has no detected effect. PMID:26743904

  6. Experiment on formulation and drug release behavior of porosity asymmetric membrane capsules in vitro.

    PubMed

    Fu, Hong-Xing; Li, Hui; Zhang, Fu-Zhi; Zhao, Ying-Zheng; Wan, Chang-Wei; Chen, Mi-Te; Jia, Xue-Chao; Yan, Li; Sun, Chuan-Chuan; Xu, Yan-Yan

    2012-06-01

    Porosity asymmetric membrane capsules were prepared to study the relationship between the capsule formulation and drug release. Cellulose acetate (CA) and pore formers were used in the capsule shell formulation as the main semipermeable membrane material. The capsules were permeable to both water and dissolved solutes. Using sparingly soluble drug acetaminophen as a model, cumulative release was calculated. The slope of the release profile from the distilled water had good relationship with the concentration of the pore formers F68. The release of acetaminophen was independent to the pH, osmotic pressure of dissolution medium, but influenced by intensity of agitation. When the concentration of pore former was low, zero-order release behavior was observed within 24 h which was consistent with Fickian diffusion model. When the concentration of pore former was high, however, Higuchi model release was found which is caused by Fickian diffusion and osmotic pressure release. With scanning electron microscope (SEM), the surface structure and cross-section of the capsule shell were also studied before and after drug delivery. With simple preparation and broad scope of drug application, porosity asymmetric membrane capsules can give desired drug extended release and show more convenience than controlled tablets with laser drilling.

  7. Gas retention and release behavior in Hanford single-shell waste tanks

    SciTech Connect

    Stewart, C.W.; Brewster, M.E.; Gauglitz, P.A.; Mahoney, L.A.; Meyer, P.A.; Recknagle, K.P.; Reid, H.C.

    1996-12-01

    This report describes the current understanding of flammable gas retention and release in Hanford single-shell waste tanks based on theory, experimental results, and observations of tank behavior. The single-shell tanks likely to pose a flammable gas hazard are listed and described, and photographs of core extrusions and the waste surface are included. The credible mechanisms for significant flammable gas releases are described, and release volumes and rates are quantified as much as possible. The only mechanism demonstrably capable of producing large ({approximately}100 m{sup 3}) spontaneous gas releases is the buoyant displacement, which occurs only in tanks with a relatively deep layer of supernatant liquid. Only the double-shell tanks currently satisfy this condition. All release mechanisms believed plausible in single-shell tanks have been investigated, and none have the potential for large spontaneous gas releases. Only small spontaneous gas releases of several cubic meters are likely by these mechanisms. The reasons several other postulated gas release mechanisms are implausible or incredible are also given.

  8. Nanohybrid structure analysis and biomolecule release behavior of polysaccharide-CDHA drug carriers

    NASA Astrophysics Data System (ADS)

    Huang, Li-Ying; Liu, Ting-Yu; Liu, Tse-Ying; Mevold, Andreas; Hardiansyah, Andri; Liao, Hung-Chou; Lin, Chin-Ching; Yang, Ming-Chien

    2013-10-01

    Nanoscaled polymer composites were prepared from polysaccharide chitosan (CS) and Ca-deficient hydroxyapatite (CDHA). CS-CDHA nanocomposites were synthesized by in situ precipitation at pH 9, and the CS-CDHA carriers were then fabricated by ionic cross-linking methods using tripolyphosphate and chemical cross-linking methods by glutaraldehyde and genipin. Certain biomolecules such as vitamin B12, cytochrome c, and bovine serum albumin were loaded into the CS-CDHA carriers, and their release behaviors were investigated. Furthermore, these CS-CDHA carriers were examined by transmission electron microscopy, electron spectroscopy for chemical analysis, and X-ray diffraction. The release behavior of the biomolecules was controlled by the CS/CDHA ratios and cross-linked agents. By increasing the concentration of CS and the concentration of the cross-linking agents, cross-linking within carriers increases, and the release rate of the biomolecules is decreased. Moreover, the release rate of the biomolecules from the CS-CDHA carriers at pH 4 was higher than that at pH 10, displaying a pH-sensitive behavior. Therefore, these CS-CDHA hydrogel beads may be useful for intelligent drug release and accelerate bone reconstruction.

  9. On-Line Analysis and Kinetic Behavior of Arsenic Release during Coal Combustion and Pyrolysis.

    PubMed

    Shen, Fenghua; Liu, Jing; Zhang, Zhen; Dai, Jinxin

    2015-11-17

    The kinetic behavior of arsenic (As) release during coal combustion and pyrolysis in a fluidized bed was investigated by applying an on-line analysis system of trace elements in flue gas. This system, based on inductively coupled plasma optical emission spectroscopy (ICP-OES), was developed to measure trace elements concentrations in flue gas quantitatively and continuously. Obvious variations of arsenic concentration in flue gas were observed during coal combustion and pyrolysis, indicating strong influences of atmosphere and temperature on arsenic release behavior. Kinetic laws governing the arsenic release during coal combustion and pyrolysis were determined based on the results of instantaneous arsenic concentration in flue gas. A second-order kinetic law was determined for arsenic release during coal combustion, and the arsenic release during coal pyrolysis followed a fourth-order kinetic law. The results showed that the arsenic release rate during coal pyrolysis was faster than that during coal combustion. Thermodynamic calculations were carried out to identify the forms of arsenic in vapor and solid phases during coal combustion and pyrolysis, respectively. Ca3(AsO4)2 and Ca(AsO2)2 are the possible species resulting from As-Ca interaction during coal combustion. Ca(AsO2)2 is the most probable species during coal pyrolysis.

  10. Gas retention and release behavior in Hanford double-shell waste tanks

    SciTech Connect

    Meyer, P.A.; Brewster, M.E.; Bryan, S.A.

    1997-05-01

    This report describes the current understanding of flammable gas retention and release in Hanford double-shell waste tanks AN-103, AN-104, AN-105, AW-101, SY-101, and SY-103. This knowledge is based on analyses, experimental results, and observations of tank behavior. The applicable data available from the void fraction instrument, retained gas sampler, ball rheometer, tank characterization, and field monitoring are summarized. Retained gas volumes and void fractions are updated with these new data. Using the retained gas compositions from the retained gas sampler, peak dome pressures during a gas burn are calculated as a function of the fraction of retained gas hypothetically released instantaneously into the tank head space. Models and criteria are given for gas generation, initiation of buoyant displacement, and resulting gas release; and predictions are compared with observed tank behavior.

  11. Effect of methyl cellulose on gelation behavior and drug release from poloxamer based ophthalmic formulations.

    PubMed

    Dewan, Mitali; Bhowmick, Biplab; Sarkar, Gunjan; Rana, Dipak; Bain, Mrinal Kanti; Bhowmik, Manas; Chattopadhyay, Dipankar

    2015-01-01

    The effect of weight average molecular weight (Mw) of methyl cellulose (MC) on the gelation behavior of Poloxamer 407 (PM) and in vitro release of Ketorolac Tromethamine (KT) from different ophthalmic formulations based on PM is examined. A drop of gelation temperature of PM is observed using MC of various M(w) by test tube tilting method, UV-vis spectroscopy, viscometry and rheometry. It is also observed that the viscosity and gel strength of all the formulations are increased with the increase in Mw of MC. PM with highest Mw of MC provides best drug release property among all the formulations. It is evident from this investigation that there is a distinct effect of M(w) of MC on the gelation behavior of PM as well as on the drug release profile of KT from PM-MC based ophthalmic formulations.

  12. Preliminary analysis of graphite dust releasing behavior in accident for HTR

    SciTech Connect

    Peng, W.; Yang, X. Y.; Yu, S. Y.; Wang, J.

    2012-07-01

    The behavior of the graphite dust is important to the safety of High Temperature Gas-cooled Reactors. This study investigated the flow of graphite dust in helium mainstream. The analysis of the stresses acting on the graphite dust indicated that gas drag played the absolute leading role. Based on the understanding of the importance of gas drag, an experimental system is set up for the research of dust releasing behavior in accident. Air driven by centrifugal fan is used as the working fluid instead of helium because helium is expensive, easy to leak which make it difficult to seal. The graphite particles, with the size distribution same as in HTR, are added to the experiment loop. The graphite dust releasing behavior at the loss-of-coolant accident will be investigated by a sonic nozzle. (authors)

  13. MAOA-VNTR polymorphism modulates context-dependent dopamine release and aggressive behavior in males.

    PubMed

    Schlüter, Thorben; Winz, Oliver; Henkel, Karsten; Eggermann, Thomas; Mohammadkhani-Shali, Siamak; Dietrich, Claudia; Heinzel, Alexander; Decker, Michel; Cumming, Paul; Zerres, Klaus; Piel, Markus; Mottaghy, Felix M; Vernaleken, Ingo

    2016-01-15

    A recent [(18)F]FDOPA-PET study reports negative correlations between dopamine synthesis rates and aggressive behavior. Since dopamine is among the substrates for monoamine oxidase A (MAOA), this investigation examines whether functional allelic variants of the MAOA tandem repeat (VNTR) promotor polymorphism, which is known to modulate aggressive behavior, influences dopamine release and aggression in response to violent visual stimuli. We selected from a genetic prescreening sample, strictly case-matched groups of 2×12 healthy male subjects with VNTRs predictive of high (MAOA-High) and low (MAOA-Low) MAOA expression. Subjects underwent pairs of PET sessions (dopamine D2/3 ligand [(18)F]DMFP) while viewing a movie of neutral content, versus violent content. Directly afterwards, aggressive behavior was assessed by the Point Subtraction Aggression Paradigm (PSAP). Finally, PET data of 23 participants and behavioral data of 22 participants were analyzed due to post hoc exclusion criteria. In the genetic prescreening sample MAOA-Low carriers had significantly increased scores on the Buss-Perry Aggression Questionnaire. In the PET-study-group, aggressive behavior under the emotional neutral condition was significantly higher in the MAOA-Low group. Interestingly, the two MAOA-groups showed inverse dopaminergic and behavioral reactions to the violent movie: The MAOA-High group showed higher dopamine release and increased aggression after the violent movie; MAOA-Low subjects showed decreases in aggressive behavior and no consistent dopamine release. These results indicate a possible impact of the MAOA-promotor polymorphism on the neurobiological modulation of aggressive behavior. However, the data do not support approaches stating that MAOA-Low fosters aggression by a simple pro-dopaminergic mechanism.

  14. Fabrication of dual-sensitive keratin-based polymer hydrogels and their controllable release behaviors.

    PubMed

    Sun, Kangqi; Guo, Juhua; He, Yufeng; Song, Pengfei; Xiong, Yubing; Wang, Rong-Min

    2016-10-03

    Using feather keratin (FK) as a biocompatible and inexpensive biopolymer, a kind of dual-sensitive keratin-based polymer hydrogel (FK/PNiPA/PIAc-Gel) with interpenetrating network structure was prepared by two-step polymerization of N-isopropyl acrylamide (NiPA) and itaconic acid (IAc) in presence of crosslinker. After being characterized by Fourier transform infrared spectroscopy, thermogravimetric analysis and scanning electron microscopy, its swelling behaviors and environmental sensitivity were investigated. The obtained biopolymer based hydrogel has good swelling and deswelling performance, and it is sensitive to pH value, temperature and salts of environment. Using anticancer drug, doxorubicin hydrochloride (Dox·HCl),  and Bovine serum albumin (BSA) as different drug molecules, its release behaviors in different environment were investigated. It was found that the release behaviors of FK/PNiPA/PIAc-Gel were controllable via adjusting pH value or temperature of environment. The cumulative release of the anticancer drug (Dox·HCl) reached 93.3% within 16 h, and the cumulative release rate of macromolecular drug (BSA) got to 75.9% in 24 h. In summary, the keratin-based biopolymer hydrogel with interpenetrating network structure, pH-sensitivity and temperature sensitivity are potentially applied to sustain drug carrier and humid medicinal material in the biomedical field or clinical nursing field.

  15. Simple Colorimetric Detection of Amyloid β-peptide (1-40) based on Aggregation of Gold Nanoparticles in the Presence of Copper Ions.

    PubMed

    Zhou, Yanli; Dong, Hui; Liu, Lantao; Xu, Maotian

    2015-05-13

    A simple method for specific colorimetric sensing of Alzheimer's disease related amyloid-β peptide (Aβ) is developed based on the aggregation of gold nanoparticles in the presence of copper ion. The detection of limit for Aβ(1-40) is 0.6 nM and the promising results from practical samples (human serum) indicate the great potential for the routine detection.

  16. Fluorescent sensor for selective determination of copper ion based on N-acetyl-L-cysteine capped CdHgSe quantum dots.

    PubMed

    Wang, Qingqing; Yu, Xiangyang; Zhan, Guoqing; Li, Chunya

    2014-04-15

    Using N-acetyl-L-cysteine as a stabilizer, well water-dispersed, high-quality and stable CdHgSe quantum dots were facilely synthesized via a simple aqueous phase method. The as-prepared N-acetyl-L-cysteine capped CdHgSe quantum dots were thoroughly characterized by transmission electron microscopy, X-ray diffraction spectroscopy and FTIR. A fluorescent sensor for selective determination of copper ions was developed using N-acetyl-L-cysteine capped CdHgSe quantum dots as fluorescent probe. The fluorescence intensity of N-acetyl-L-cysteine capped CdHgSe quantum dots decreased when interacted with copper ions due to the formation of coordination complex and aggregates. The method possesses high selectivity and is not influenced by some potential interferences such as Ag(+), Zn(2+), Co(2+) and Ni(2+). Under the optimal conditions, the change of fluorescence intensity (ΔI) was linearly proportional to the concentration of copper ions in the range of 1.0×10(-9)-4.0×10(-7) mol L(-1), with a detection limit as low as 2.0×10(-10) mol L(-1) (S/N=3). The developed method had been successfully employed to determine Cu(2+) in shrimp and South-lake water samples, and the results were verified by atomic absorption spectroscopy. The fluorescent sensor was demonstrated to be selective, sensitive and simple for copper ion determination, and promise for practical applications.

  17. Removal of copper ions from aqueous solution by adsorption onto novel polyelectrolyte film-coated nanofibrous silk fibroin non-wovens

    NASA Astrophysics Data System (ADS)

    Zhou, Weitao; Huang, Haitao; Du, Shan; Huo, Yingdong; He, Jianxin; Cui, Shizhong

    2015-08-01

    In this approach, polyelectrolyte film-coated nanofibrous silk fibroin (SF) nonwovens were prepared from the alternate deposition of positively charged polyethylenimine (PEI) and negatively charged SF using electrostatic layer-by-layer (LBL) self-assembled technology. The composite membranes were characterized by scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectrometer. The SF-PEI multilayer-assembled nanofibers (less than five layers) were fine and uniform with the fiber diameter from 400 nm to 600 nm, and had very large surface area and high porosity (more than 70%). The amino groups of PEI were proved to be deposited onto SF nonwovens, which granted the coated nonwovens with potential applicability for copper ions adsorption. The PEI films coated SF substrate showed much higher copper ions adsorption capacity than that of ethanol treated SF nanofibers. Adding the number of PEI coated could enhance the Cu2+ adsorption capacity significantly. The maximum milligrams per gram of copper ions adsorbed reached 59.7 mg/g when the SF substrate was coated with 5 bilayers of SF-PEI. However, the copper ions adsorption capacity had no obvious change as the number of PEI continued to increase. These results suggest potential for PEL film-coated nanofibrous nonwovens as a new adsorbent for metal ions.

  18. A room temperature nitric oxide gas sensor based on a copper-ion-doped polyaniline/tungsten oxide nanocomposite.

    PubMed

    Wang, Shih-Han; Shen, Chi-Yen; Su, Jian-Ming; Chang, Shiang-Wen

    2015-03-24

    The parts-per-billion-level nitric oxide (NO) gas sensing capability of a copper-ion-doped polyaniline/tungsten oxide nanocomposite (Cu(2+)/PANI/WO3) film coated on a Rayleigh surface acoustic wave device was investigated. The sensor developed in this study was sensitive to NO gas at room temperature in dry nitrogen. The surface morphology, dopant distribution, and electric properties were characterized using scanning electron microscopy, energy-dispersive X-ray spectroscopy mapping, and Hall effect measurements, respectively. The Cu(2+)/PANI/WO3 film exhibited high NO gas sensitivity and selectivity as well as long-term stability. At 1 ppb of NO, a signal with a frequency shift of 4.3 ppm and a signal-to-noise ratio of 17 was observed. The sensor exhibited distinct selectivity toward NO gas with no substantial response to O2, NH3 and CO2 gases.

  19. Experimental study on the initiation and energy release behavior of polymer bonded explosive materials

    NASA Astrophysics Data System (ADS)

    Zhang, Wei; Cai, Xuanming; Ye, Nan; Gao, Yubo

    2017-01-01

    In this paper, an initially sealed vented test chamber and a test projectile with polymer bonded explosive materials were designed to complete the experiments. As the initiation takes place on the interior, great amounts of thermo-chemical energy gases were vented through a hole formed by the penetration process. The gas pressure inside the chamber was used to evaluate the energy release behavior of polymer bonded explosive materials. The experimental results reveal that the impact velocity is significant to the energy release behavior, and in some extent the gas pressure improves with the velocity of the projectile. And the critical initiation velocity and the velocity as the polymer bonded explosive materials reached the maximum reactive efficiency were obtained.

  20. The Shock and Release Behavior of Diamond Compressed to 25 Mbar

    NASA Astrophysics Data System (ADS)

    Gregor, M. C.

    2016-10-01

    The behavior of carbon at high pressure is important to the study of ice giants and white dwarfs, and because diamond is used as an ablator for inertial confinement fusion (ICF) targets at the National Ignition Facility (NIF). The adiabat of an ICF implosion is determined by a series of shocks that transit the ablator and fuel layer. To accurately model an implosion and design ignition targets, both the Hugoniot and the release behavior of the ablator material must be known. We report on experiments on the OMEGA laser that shocked diamond samples up to 25 Mbar, which then released into reference materials with known Hugoniots (quartz, 200-mg/cm3 SiO2 foam, liquid deuterium, and polystyrene). The impedance-matching technique with these reference materials provided data that constrains release models for diamond. This technique is applied to two forms of diamond: single-crystal and ultra-nanocrystalline diamond (UNCD); the latter is the NIF ablator material. Models for the release isentropes of both types of diamond will be developed using a Mie-Grüneisen equation of state. This study also provided Hugoniot data for UNCD using the impedance-matching technique with a quartz standard. The accuracy of these data was improved by implementing an unsteady wave correction to determine instantaneous shock velocities in the opaque UNCD samples. This material is based upon work supported by the Department of Energy National Nuclear Security Administration under Award Number DE-NA0001944.

  1. Models for recurrent gas release event behavior in hazardous waste tanks

    SciTech Connect

    Anderson, D.N.; Arnold, B.C.

    1994-08-01

    Certain radioactive waste storage tanks at the United States Department of Energy Hanford facilities continuously generate gases as a result of radiolysis and chemical reactions. The congealed sludge in these tanks traps the gases and causes the level of the waste within the tanks to rise. The waste level continues to rise until the sludge becomes buoyant and ``rolls over``, changing places with heavier fluid on top. During a rollover, the trapped gases are released, resulting, in a sudden drop in the waste level. This is known as a gas release event (GRE). After a GRE, the wastes leading to another GRE. We present nonlinear time waste re-congeals and gas again accumulates leading to another GRE. We present nonlinear time series models that produce simulated sample paths that closely resemble the temporal history of waste levels in these tanks. The models also imitate the random GRE, behavior observed in the temporal waste level history of a storage tank. We are interested in using the structure of these models to understand the probabilistic behavior of the random variable ``time between consecutive GRE`s``. Understanding the stochastic nature of this random variable is important because the hydrogen and nitrous oxide gases released from a GRE, are flammable and the ammonia that is released is a health risk. From a safety perspective, activity around such waste tanks should be halted when a GRE is imminent. With credible GRE models, we can establish time windows in which waste tank research and maintenance activities can be safely performed.

  2. Immunoneutralization of gonadotropin-releasing hormone type-III suppresses male reproductive behavior of cichlids.

    PubMed

    Ogawa, Satoshi; Akiyama, Go; Kato, Shumei; Soga, Tomoko; Sakuma, Yasuo; Parhar, Ishwar S

    2006-08-07

    To investigate the roles of gonadotropin-releasing hormone (GnRH) types in reproductive behaviors, antisera against GnRH1, GnRH2 and GnRH3 were stereotaxically administered into the intracerebroventricular region to neutralize the three native GnRH types in the brain of male tilapia Oreochromis niloticus. Reproductive behaviors (nest-building and aggressive behaviors), and morphological changes of the three GnRH systems were investigated by immunocytochemistry. GnRH1, GnRH2 and GnRH3 immunoreactive fibers were significantly decreased following injections of GnRH antisera indicating successful neutralization of their respective endogenous GnRH peptides. GnRH1- and GnRH2-immunoneutralization did not inhibit reproductive behaviors but GnRH3-immunoneutralization significantly decreased nest-building ability (Saline: 26.5 +/- 3.7%/day versus GnRH3: 6.1 +/- 2.9%/day, P < 0.001), nest size (Saline: 0.67 +/- 0.09 points versus GnRH3: 0.10 +/- 0.05 points, P < 0.0002) and aggressive behavior (Saline: 2.34 +/- 0.19 points versus GnRH3 1.06 +/- 0.12 points, P < 0.0001). These observations provide evidence that GnRH3 is a potent neuromodulator of reproductive behaviors in male tilapia.

  3. Botulinum toxin B in the sensory afferent: transmitter release, spinal activation, and pain behavior.

    PubMed

    Marino, Marc J; Terashima, Tetsuji; Steinauer, Joanne J; Eddinger, Kelly A; Yaksh, Tony L; Xu, Qinghao

    2014-04-01

    We addressed the hypothesis that intraplantar botulinum toxin B (rimabotulinumtoxin B: BoNT-B) has an early local effect upon peripheral afferent terminal releasing function and, over time, will be transported to the central terminals of the primary afferent. Once in the terminals it will cleave synaptic protein, block spinal afferent transmitter release, and thereby prevent spinal nociceptive excitation and behavior. In mice, C57Bl/6 males, intraplantar BoNT-B (1 U) given unilaterally into the hind paw had no effect upon survival or motor function, but ipsilaterally decreased: (1) intraplantar formalin-evoked flinching; (2) intraplantar capsaicin-evoked plasma extravasation in the hind paw measured by Evans blue in the paw; (3) intraplantar formalin-evoked dorsal horn substance P (SP) release (neurokinin 1 [NK1] receptor internalization); (4) intraplantar formalin-evoked dorsal horn neuronal activation (c-fos); (5) ipsilateral dorsal root ganglion (DRG) vesicle-associated membrane protein (VAMP); (6) ipsilateral SP release otherwise evoked bilaterally by intrathecal capsaicin; (7) ipsilateral activation of c-fos otherwise evoked bilaterally by intrathecal SP. These results indicate that BoNT-B, after unilateral intraplantar delivery, is taken up by the peripheral terminal, is locally active (blocking plasma extravasation), is transported to the ipsilateral DRG to cleave VAMP, and is acting presynaptically to block release from the spinal peptidergic terminal. The observations following intrathecal SP offer evidence for a possible transsynaptic effect of intraplantar BoNT. These results provide robust evidence that peripheral BoNT-B can alter peripheral and central terminal release from a nociceptor and attenuate downstream nociceptive processing via a presynaptic effect, with further evidence suggesting a possible postsynaptic effect.

  4. Preparation of alginate hydrogels through solution extrusion and the release behavior of different drugs.

    PubMed

    Liu, Guiting; Zhou, Hongxun; Wu, Hong; Chen, Rong; Guo, Shaoyun

    2016-10-07

    Homogeneous alginate hydrogels were facilely fabricated through solution extrusion process. CaCO3 and D-glucono-δ-lactone (GDL) were used as the gelation agents. The slow gelation of alginate was realized by the in-situ release of Ca(2+) from CaCO3 particles induced by hydrolysis of GDL to reduce pH. Slight gelation during the extrusion caused the enhanced strength of the alginate solutions, leading to the extrudability of the blends. This method enables to produce alginate hydrogels in a single step via extrusion, which is economically advantageous to conventional lab-scale preparation for mass production. Three different drugs, ibuprofen, acetaminophen, and methylthionine chloride, were used as model drugs to evaluate the drug release behavior of the alginate hydrogels. It was demonstrated that the drug release behavior was significantly adjusted by both the drug solubility and the ionic interaction between alginate and the drug molecule. It was shown that solution extrusion process is a feasible method to produce alginate-based drug delivery systems.

  5. Enhancement of a dynamic porous model considering compression-release hysteresis behavior: application to graphite

    NASA Astrophysics Data System (ADS)

    Jodar, B.; Seisson, G.; Hébert, D.; Bertron, I.; Boustie, M.; Berthe, L.

    2016-08-01

    Because of their shock wave attenuation properties, porous materials and foams are increasingly used for various applications such as graphite in the aerospace industry and polyurethane (PU) foams in biomedical engineering. For these two materials, the absence of residual compaction after compression and release cycles limits the efficiency of the usual numerical dynamic porous models such as P-α and POREQST. In this paper, we suggest a simple enhancement of the latter in order to take into account the compression-release hysteresis behavior experimentally observed for the considered materials. The new model, named H-POREQST, was implemented into a Lagrangian hydrocode and tested for simulating plate impact experiments at moderate pressure onto a commercial grade of porous graphite (EDM3). It proved to be in far better agreement with experimental data than the original model which encourages us to pursue numerical tests and developments.

  6. Computer simulation of material behavior at the notch tip: Effect of microrotations on elastic energy release

    NASA Astrophysics Data System (ADS)

    Moiseenko, D. D.; Panin, S. V.; Maksimov, P. V.; Panin, V. E.; Babich, D. S.; Berto, F.

    2016-11-01

    The paper is devoted to detailed investigation of rotational deformation modes at the notch tip during shock loading. Using hybrid discrete-continuum approach of Excitable Cellular Automata the series of numerical experiments were conducted to simulate deformation behavior of ductile steel in the vicinities of U-, I- and V-notches. The detailed analysis of the force moment distribution at the notch tip allowed revealing the relationship between the rotational deformation modes at different scales. It was found that the elastic energy release is realized by means of the modulation of the magnitude and the sign of the force moment. The obtained results makes possible to optimize crystal structure for improvement of mechanical properties of the material in the way of elastic energy release by reversible microrotations.

  7. Calcein release behavior from liposomal bilayer; influence of physicochemical/mechanical/structural properties of lipids.

    PubMed

    Maherani, Behnoush; Arab-Tehrany, Elmira; Kheirolomoom, Azadeh; Geny, David; Linder, Michel

    2013-11-01

    The design of the drug delivery depends upon different parameters. One of the most noticeable factors in design of the drug delivery is drug-release profile which determines the site of action, the concentration of the drug at the time of administration, the period of time that the drug must remain at a therapeutic concentration. To get a better understanding of drug release, large unilamellar liposomes containing calcein were prepared using 1,2-dioleoyl-sn-glycero-3-phosphocholine, 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine and 1,2-palmitoyl-sn-glycero-3-phosphocholine, and a mixture of them; calcein was chosen as a model of hydrophilic drug. The calcein permeability across liposomal membrane (with different compositions) was evaluated on the basis of the first-order kinetic by spectrofluorometer. Also, the effects of liposome composition/fluidity as well as the incubation temperature/pH were investigated. Furthermore, we simulated the digestion condition in the gastrointestinal tract in humans, to mimic human gastro-duodenal digestion to monitor calcein release during the course of the digestion process. In vitro digestion model ''pH stat'' was used to systematically examine the influence of pH/enzyme on phospholipid liposomes digestion under simulated gastro-duodenal digestion. The results revealed that calcein permeates across liposomal membrane without membrane disruption. The release rate of calcein from the liposomes depends on the number and fluidity of bilayers and its mechanical/physical properties such as permeability, bending elasticity. Chemo-structural properties of drugs like as partition coefficient (Log P), H-bonding, polar surface area (PSA) are also determinative parameter in release behavior. Finally, stimulated emission depletion (STED) microscopy was used to study calcein translocation through liposomal bilayers.

  8. Denitrification and neutralization treatment by direct feeding of an acidic wastewater containing copper ion and high-strength nitrate to a bio-electrochemical reactor process.

    PubMed

    Watanabe, T; Motoyama, H; Kuroda, M

    2001-12-01

    The feasibility of the direct denitrification treatment of copper metal pickling wastewater by using a bio-electrochemical reactor process was investigated experimentally. Carbon electrodes were installed in the reactor as the anode and cathode and denitrifying microorganisms were fixed on the surface of the cathode. The reactor was continuously operated by applying an electric current and feeding acetate. In this reactor, copper ion removal and denitrification proceeded simultaneously and the pH value of the treated water was increased almost to neutral. The electric current that passed through the cathode contributed to the removal of the copper ion and the generation of hydrogen gas. The generated hydrogen gas as well as the added acetate was effectively utilized for denitrification. A theoretical evaluation of pH in the effluent suggested that the pH increase was mainly caused by the generation of hydroxyl ion during denitrification. In addition, the inorganic carbon species generated during denitrification with acetate and by the electrochemical oxidation of anodic carbon acted as a buffer to minimize a further increase of pH at higher nitrate removal efficiencies. These results demonstrated that copper ion removal, denitrification and neutralization could be achieved simultaneously by using a single bioelectrochemical reactor.

  9. Cloning, crystallization and preliminary X-ray studies of XC2981 from Xanthomonas campestris, a putative CutA1 protein involved in copper-ion homeostasis

    SciTech Connect

    Lin, Chien-Hung; Chin, Ko-Hsin; Gao, Fei Philip; Lyu, Ping-Chiang; Shr, Hui-Lin; Wang, Andrew H.-J.; Chou, Shan-Ho

    2006-11-01

    A probable copper-ion tolerance protein from the plant pathogen X. campestris has been overexpressed in E. coli, purified and crystallized. Divalent metal ions play key roles in all living organisms, serving as cofactors for many proteins involved in a variety of electron-transfer activities. However, copper ions are highly toxic when an excessive amount is accumulated in a cell. CutA1 is a protein found in all kingdoms of life that is believed to participate in copper-ion tolerance in Escherichia coli, although its specific function remains unknown. Several crystal structures of multimeric CutA1 with different rotation angles and degrees of interaction between trimer interfaces have been reported. Here, the cloning, expression, crystallization and preliminary X-ray analysis of XC2981, a possible CutA1 protein present in the plant pathogen Xanthomonas campestris, are reported. The XC2981 crystals diffracted to a resolution of 2.6 Å. They are cubic and belong to space group I23, with unit-cell parameters a = b = c = 130.73 Å.

  10. Copper ion-stimulated McoA-laccase production and enzyme characterization in Proteus hauseri ZMd44.

    PubMed

    Zheng, Xuesong; Ng, I-Son; Ye, Chiming; Chen, Bor-Yann; Lu, Yinghua

    2013-04-01

    The novel bioelectricity-generating bacterium of Proteus hauseri ZMd44 has been first identified to produce McoA-laccase (EC 1.10.3.2) induced by copper sulphate. The optimal concentration of copper is 3 mM as supplementation at the beginning of culture or early exponential growth phase, during which laccase is predominantly synthesized. Moreover, the whole cellular and intracellular activities of laccase increase in the degrees of inducible copper concentrations. A possible mechanism for this phenomenon is that copper ions enhance the laccase genetic transcription level during the laccase synthesis thus granting this strain in copper tolerance. McoA-laccase belongs to typical type 1 (T1) Cu site laccase by electron paramagnetic resonance (EPR) analysis of intracellular enzyme. From our results, the optimal temperature and pH are 60°C and pH 2.2, respectively. The kinetic profiles show that this enzyme is stable under 50°C and in the slightly acidic environment, making it a potentially useful enzyme in dye decolorization, paper-pulp bleaching and bioremediation industries.

  11. Mobilization of Copper ions by Flavonoids in Human Peripheral Lymphocytes Leads to Oxidative DNA Breakage: A Structure Activity Study.

    PubMed

    Arif, Hussain; Rehmani, Nida; Farhan, Mohd; Ahmad, Aamir; Hadi, Sheikh Mumtaz

    2015-11-09

    Epidemiological studies have linked dietary consumption of plant polyphenols with lower incidence of various cancers. In particular, flavonoids (present in onion, tomato and other plant sources) induce apoptosis and cytotoxicity in cancer cells. These can therefore be used as lead compounds for the synthesis of novel anticancer drugs with greater bioavailability. In the present study, we examined the chemical basis of cytotoxicity of flavonoids by studying the structure-activity relationship of myricetin (MN), fisetin (FN), quercetin (QN), kaempferol (KL) and galangin (GN). Using single cell alkaline gel electrophoresis (comet assay), we established the relative efficiency of cellular DNA breakage as MN > FN > QN > KL > GN. Also, we determined that the cellular DNA breakage was the result of mobilization of chromatin-bound copper ions and the generation of reactive oxygen species. The relative DNA binding affinity order was further confirmed using molecular docking and thermodynamic studies through the interaction of flavonoids with calf thymus DNA. Our results suggest that novel anti-cancer molecules should have ortho-dihydroxy groups in B-ring and hydroxyl groups at positions 3 and 5 in the A-ring system. Additional hydroxyl groups at other positions further enhance the cellular cytotoxicity of the flavonoids.

  12. Imprint Molding of a Microfluidic Optical Cell on Thermoplastics with Reduced Surface Roughness for the Detection of Copper Ions.

    PubMed

    Wu, Jing; Lee, Nae Yoon

    2016-01-01

    Here, we introduce a simple and facile technique for fabricating microfluidic optical cells by utilizing a micropatterned polymer mold, followed by imprinting on thermoplastic substrates. This process has reduced the surface roughness of the microchannel, making it suitable for microscale optical measurements. The micropatterned polymer mold was fabricated by first micromilling on a poly(methylmethacrylate) (PMMA) substrate, and then transferring the micropattern onto an ultraviolet (UV)-curable optical adhesive. After an anti-adhesion treatment of the polymer mold fabricated using the UV-curable optical adhesive, the polymer mold was used repeatedly for imprinting onto various thermoplastics, such as PMMA, polycarbonate (PC), and poly(ethyleneterephthalate) (PET). The roughness values for the PMMA, PC, and PET microchannels were approximately 11.3, 20.3, and 14.2 nm, respectively, as compared to those obtained by micromilling alone, which were 15.9, 76.8, and 207.5 nm, respectively. Using the imprint-molded thermoplastic optical cell, rhodamine B and copper ions were successfully quantified. The reduced roughness of the microchannel surface resulted in improved sensitivity and reduced noise, paving the way for integration of the detection module so as to realize totally integrated microdevices.

  13. The stable and water-soluble neodymium-doped lanthanide fluoride nanoparticles for near infrared probing of copper ion.

    PubMed

    Xue, Fang-Min; Wang, He-Fang

    2012-09-15

    Neodymium (Nd(3+)) doped nanomaterials exhibited the unique near infrared (NIR) luminescence properties. However, the application of Nd-doped nanomaterials to chemosensors was rarely explored. Herein, the water-soluble 2-aminoethyl dihydrogen phosphate stabilized Nd-doped LaF(3) (ADP-Nd-LaF(3)) nanoparticles were explored as the NIR probe for chemosensors. The NIR emission intensity at 1061 nm of ADP-Nd-LaF(3) nanoparticles kept stable in the aqueous solution of various pH and coexisting of most common metal ions except copper ion, consequently, the ADP-Nd-LaF(3) nanoparticles were developed as a high selective NIR probe for Cu(II). The NIR emission of ADP-Nd-LaF(3) exhibits a linear quenching response to Cu(II) in the range 5-100 μM, with a detection limit of 0.8 μM. The precision of eleven replicate detections of 5 μM Cu(II) was 0.5% (RSD). The recovery of spiked Cu(II) in human urine and waste water samples ranged from 102 to 109%. The possible mechanism of Cu(II)-induced fluorescence quenching of ADP-Nd-LaF(3) nanoparticles was also discussed.

  14. Using copper ions to amplify ROS-mediated fluorescence for continuous online monitoring of extracellular glucose in living rat brain.

    PubMed

    Su, Cheng-Kuan; Chen, Chen-Yu; Tseng, Po-Jen; Sun, Yuh-Chang

    2015-02-15

    In this study we developed a facile and sensitive method for continuous monitoring of extracellular glucose concentration in living rat brain through microdialysis (MD) sampling in conjunction with (i) online sample derivatization using glucose oxidase to generate H2O2, which converted a reactive oxygen species-responsive fluorescent dye, 2',7'-dichlorodihydrofluorescein (DCFH), into fluorescent species, and (ii) a novel non-immobilized enzyme-based fluorescence assay strategy, featuring copper ion (Cu(2+))-facilitated amplification of the fluorescence intensity. After evaluating the experimental conditions for glucose oxidation and fluorescence generation, the introduction of Cu(2+) ions to this system resulted in an additional 51-fold amplification of the net fluorescence intensity. By sequentially loading brain microdialysate into the dual sample collection loops, the sampling frequency was 7.5h(-1). Based on a 40-μL sample volume, the system's detection limit reached as low as 0.18 mM, sufficiently accurate to determine the extracellular glucose concentrations in living rat brains. To demonstrate the proposed system's practical performance and applicability, we conducted (i) spike analyses of biomolecule-rich fetal bovine serum sample, confirming that the analytical reliability was similar to that of a commercial glucose kit, and (ii) in vivo dynamic monitoring of the extracellular glucose concentrations in living rat brains after inducing neural depolarization by perfusing a high-K(+) medium from the MD probe.

  15. Mobilization of Copper ions by Flavonoids in Human Peripheral Lymphocytes Leads to Oxidative DNA Breakage: A Structure Activity Study

    PubMed Central

    Arif, Hussain; Rehmani, Nida; Farhan, Mohd; Ahmad, Aamir; Hadi, Sheikh Mumtaz

    2015-01-01

    Epidemiological studies have linked dietary consumption of plant polyphenols with lower incidence of various cancers. In particular, flavonoids (present in onion, tomato and other plant sources) induce apoptosis and cytotoxicity in cancer cells. These can therefore be used as lead compounds for the synthesis of novel anticancer drugs with greater bioavailability. In the present study, we examined the chemical basis of cytotoxicity of flavonoids by studying the structure–activity relationship of myricetin (MN), fisetin (FN), quercetin (QN), kaempferol (KL) and galangin (GN). Using single cell alkaline gel electrophoresis (comet assay), we established the relative efficiency of cellular DNA breakage as MN > FN > QN > KL > GN. Also, we determined that the cellular DNA breakage was the result of mobilization of chromatin-bound copper ions and the generation of reactive oxygen species. The relative DNA binding affinity order was further confirmed using molecular docking and thermodynamic studies through the interaction of flavonoids with calf thymus DNA. Our results suggest that novel anti-cancer molecules should have ortho-dihydroxy groups in B-ring and hydroxyl groups at positions 3 and 5 in the A-ring system. Additional hydroxyl groups at other positions further enhance the cellular cytotoxicity of the flavonoids. PMID:26569217

  16. Porphyrin entrapment and release behavior of microporous organic hollow spheres: fluorescent alerting systems for existence of organic solvents in water.

    PubMed

    Jin, Jaewon; Kim, Bolyong; Park, Nojin; Kang, Sungah; Park, Joon Hyun; Lee, Sang Moon; Kim, Hae Jin; Son, Seung Uk

    2014-12-07

    This work reports on the controllable guest entrapment and release behavior of microporous organic hollow spheres (MOHs). Porphyrins which are soluble in both water and methanol were entrapped in the MOHs using methanol solution. The water-soluble porphyrins entrapped in MOHs were not extracted by water due to the hydrophobicity of microporous organic shells. In contrast, the porphyrins were released gradually into aqueous solution by adding water-soluble organic solvents. The release behavior depended on the kind of organic solvents used and on the alkyl chain length of the porphyrin compounds. These properties were applied for the fluorescent alert towards the existence of organic solvents in flowing aqueous media.

  17. Corticotropin-releasing factor acts via a third ventricle site to reduce exploratory behavior in rats.

    PubMed

    Spadaro, F; Berridge, C W; Baldwin, H A; Dunn, A J

    1990-06-01

    Corticotropin-releasing factor (CRF, 20-25 ng) injected into the lateral or fourth ventricles of rats decreased exploratory behavior in the multicompartment testing chamber (MCC), as assessed by decreased mean contact times with novel stimuli. This result extends similar observations made previously in mice. To investigate the site of this action of CRF, cold cream plugs injected into the cerebral ventricles of rats were used to prevent access of the CRF to specific periventricular sites. When the cerebral aqueduct was blocked with cold cream, CRF injected into the lateral ventricle, but not the fourth ventricle, decreased exploratory behavior in the MCC. These results suggest that CRF does not act in the fourth ventricle to alter behavior in the MCC, and most likely acts in the lateral or third ventricles. Cold cream blocks within the third ventricle prevented the effect of lateral ventricle administration of CRF. The clearest effects were obtained when the anteroventral portion of the third ventricle (AV3V) had been coated with cold cream. This region, which contains the organum vasculosum laminae terminalis (OVLT), was the only region blocked that showed a significant statistical interaction between the cold cream block and the effect of CRF. This result suggests that the OVLT, or regions close to it, is the primary site of the behavioral action of CRF in the MCC. It is possible that the peptide could be taken up in this region and transported to another brain site.

  18. Tritium recapture behavior at a nuclear power reactor due to airborne releases.

    PubMed

    Harris, Jason T; Miller, David W; Foster, Doug W

    2008-08-01

    This paper describes the initiatives taken by Cook Nuclear Plant to study the on-site behavior of recaptured tritium released in its airborne effluents. Recapture is the process where a released radioactive effluent, in this case tritium, is brought back on-site through some mechanism. Precipitation, shifts in wind direction, or anthropogenic structures that restrict or alter effluent movement can all lead to recapture. The investigation was started after tritium was detected in the north storm drain outfall. Recent inadvertent tritium releases by several other nuclear power plants, many of which entered the groundwater, have led to increased surveillance and scrutiny by regulatory authorities and the general public. To determine the source of tritium in the outfall, an on-site surface water, well water, rainwater and air-conditioning condensate monitoring program was begun. Washout coefficients were also determined to compare with results reported by other nuclear power plants. Program monitoring revealed detectable tritium concentrations in several precipitation sample locations downwind of the two monitored containment building release vents. Tritium was found in higher concentrations in air-conditioning condensate, with a mean value of 528 Bq L(-1) (14,300 pCi L(-1)). The condensate, and to a lesser extent rainwater, were contributing to the tritium found in the north storm drain outfall. Maximum concentration values for each sample type were used to estimate the most conservative dose. A maximum dose of 1.1 x 10(-10) mSv (1.1 x 10(-8) mrem) total body was calculated to determine the health impact of the tritium detected.

  19. Effect of methylcellulose on the formation and drug release behavior of silk fibroin hydrogel.

    PubMed

    Park, Cho Hee; Jeong, Lim; Cho, Donghwan; Kwon, Oh Hyeong; Park, Won Ho

    2013-10-15

    In this study, methylcellulose (MC) was used to control the gelation time of silk fibroin (SF) aqueous solution. The gelation time was measured using a Vibro Viscometer at 50 °C. Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), and a texture meter were used to investigate the effect of MC on the hydrogelation of SF solution. SF/MC hydrogels could be formed by the addition of MC, although their gelation time was increased with MC content. To examine the conformational change of SF/MC hydrogels, time-resolved FT-IR spectra were obtained at constant temperature using a custom-made IR chamber. From FT-IR spectra focused on the amide I peak position, the transition of SF molecules in SF/MC solution from a random coil to a β-sheet structure was inhibited in the presence of MC molecules. In addition, the drug release of SF/MC hydrogels loaded with 5-aminosalicylic acid was studied in 2-dimensional (2-D) and 3-dimensional (3-D) conditions in vitro. The drug release behavior of SF or SF/MC hydrogels was measured using UV-Vis spectroscopy. The release rate of 5-aminosalicylic acid in SF/MC hydrogel was lower than that of SF hydrogel, which may be closely associated with the hydrophilic interaction between MC and 5-aminosalicylic acid. This approach to controlling the sol-gel transition and the drug release of SF hydrogels by the addition of MC will be useful in the design and tailoring of novel materials for biomedical applications.

  20. Loss of hypothalamic corticotropin-releasing hormone markedly reduces anxiety behaviors in mice

    PubMed Central

    Zhang, Rong; Asai, Masato; Mahoney, Carrie E; Joachim, Maria; Shen, Yuan; Gunner, Georgia; Majzoub, Joseph A

    2016-01-01

    A long-standing paradigm posits that hypothalamic corticotropin-releasing hormone (CRH) regulates neuroendocrine functions such as adrenal glucocorticoid release, while extra-hypothalamic CRH plays a key role in stressor-triggered behaviors. Here we report that hypothalamus-specific Crh knockout mice (Sim1CrhKO mice, created by crossing Crhflox with Sim1Cre mice) have absent Crh mRNA and peptide mainly in the paraventricular nucleus of the hypothalamus (PVH) but preserved Crh expression in other brain regions including amygdala and cerebral cortex. As expected, Sim1CrhKO mice exhibit adrenal atrophy as well as decreased basal, diurnal and stressor-stimulated plasma corticosterone secretion and basal plasma ACTH, but surprisingly, have a profound anxiolytic phenotype when evaluated using multiple stressors including open field, elevated plus maze, holeboard, light-dark box, and novel object recognition task. Restoring plasma corticosterone did not reverse the anxiolytic phenotype of Sim1CrhKO mice. Crh-Cre driver mice revealed that PVHCrh fibers project abundantly to cingulate cortex and the nucleus accumbens shell, and moderately to medial amygdala, locus coeruleus, and solitary tract, consistent with the existence of PVHCrh-dependent behavioral pathways. Although previous, nonselective attenuation of CRH production or action, genetically in mice and pharmacologically in humans, respectively, has not produced the anticipated anxiolytic effects, our data show that targeted interference specifically with hypothalamic Crh expression results in anxiolysis. Our data identify neurons that express both Sim1 and Crh as a cellular entry point into the study of CRH-mediated, anxiety-like behaviors and their therapeutic attenuation. PMID:27595593

  1. In vitro drug release and percutaneous behavior of poloxamer-based hydrogel formulation containing traditional Chinese medicine.

    PubMed

    Wang, Wenyi; Hui, Patrick C L; Wat, Elaine; Ng, Frency S F; Kan, Chi-Wai; Wang, Xiaowen; Wong, Eric C W; Hu, Huawen; Chan, Ben; Lau, Clara B S; Leung, Ping-Chung

    2016-12-01

    For the treatment of atopic dermatitis (AD), we have developed a transdermal functionalized textile therapy based on thermosensitive poloxamer 407 (P407) hydrogel containing a traditional Chinese herbal medicine. This study aims to investigate the effects of various formulation variables of P407/carboxymethyl cellulose sodium (P407/CMCs) composite hydrogel on the release of Cortex Moutan (CM) extract. Concentrations of P407 and CMCs showed significant influence on the release due to alteration of bulk viscosity of the system. An increase in pH values of release medium was found to appreciably impede the release of polar drug (CM) due to ionization. Elevated temperatures were also shown to facilitate the drug release. Moreover, the diffusional release behavior of CM from P407/CMCs composite hydrogel was found to follow the first-order kinetic model. Additionally, transdermal studies showed that permeability of the drug through the skin can be enhanced with addition of CMCs in the hydrogel formulation.

  2. Preparation and copper ions adsorption properties of thiosemicarbazide chitosan from squid pens.

    PubMed

    Lin, Yue-Cheng; Wang, Hong-Peng; Gohar, Faryal; Ullah, Muhammad Haseeb; Zhang, Xiang; Xie, Dong-Fang; Fang, Hui; Huang, Jun; Yang, Jun-Xing

    2017-02-01

    Chitosan was prepared by alkaline N-deacetylation of β-chitin from squid pens. Thiosemicarbazide group was introduced to chitosan via formaldehyde-derived linkages, and thiosemicarbazide chitosan (TSFCS) with different degrees of substitution (DS) was synthesized. The DS values of TSFCS calculated by elemental analysis were 0.19, 0.36 and 0.63. The structure of the TSFCS was confirmed by elemental analysis, FTIR, XRD, TGA and SEM. The adsorption capacity of Cu(II) ions by TSFCS showed good correlation with the DS and pH (pH range 2.2-5.8). The maximum Cu(II) ions adsorption capacity of all three TSFCS samples reached 134.0mgg(-1) at pH 3.6, but chitosan showed no adsorption at this pH. The adsorption equilibrium process of Cu(II) ions onto TSFCS was better described by the Langmuir model than the Freundlich isotherm model. Cu(II) ions adsorbed by TSFCS could be released using 0.01M Na2EDTA and the adsorption capacity could retain above 80% after five adsorption-desorption cycles. TSFCS exhibited good potential for heavy metal removal because of its high adsorption capacity at the low pH.

  3. New generation super alloy candidates for medical applications: corrosion behavior, cation release and biological evaluation.

    PubMed

    Reclaru, L; Ziegenhagen, R; Unger, R E; Eschler, P Y; Constantin, F

    2014-12-01

    Three super alloy candidates (X1 CrNiMoMnW 24-22-6-3-2 N, NiCr21 MoNbFe 8-3-5 AlTi, CoNiCr 35-20 Mo 10 BTi) for a prolonged contact with skin are evaluated in comparison with two reference austenitic stainless steels 316L and 904L. Several electrochemical parameters were measured and determined (E(oc), E(corr), i(corr), b(a), b(c), E(b), R(p), E(crev) and coulometric analysis) in order to compare the corrosion behavior. The cation release evaluation and in vitro biological characterization also were performed. In terms of corrosion, the results reveal that the 904L steels presented the best behavior followed by the super austenitic steel X1 CrNiMoMnW 24-22-6-3-2 N. For the other two super alloys (NiCr and CoNiCr types alloys) tested in different conditions (annealed, work hardened and work hardened+age hardened) it was found that their behavior to corrosion was weak and close to the other reference stainless steel, 316L. Regarding the extraction a mixture of cations in relatively high concentrations was noted and therefore a cocktail effect was not excluded. The results obtained in the biological assays WST-1 and TNF-alpha were in correlation with the corrosion and extraction evaluation.

  4. Adsorption and desorption behavior of copper ions on Na-montmorillonite: effect of rhamnolipids and pH.

    PubMed

    Ozdemir, Günseli; Yapar, Saadet

    2009-07-30

    In this work, the effects of an anionic biosurfactant, rhamnolipid (RL), and pH on the adsorption and desorption of Cu(2+) ions on Na-montmorillonite were investigated. Adsorption studies were conducted through the addition of Cu(2+) to the dispersions containing pristine- and/or RL-modified clay. In the case of pristine clay, RL was also added simultaneously with the Cu(2+). The effect of pH was studied in the range between 1.0 and 8.0. The highest adsorption capacity was obtained at the pH of 4.7-4.8. Among the models including the Langmuir, Freundlich and Dubinin-Kaganer-Radushkevich isotherms; Langmuir isotherm gave a better fit to the experimental data. The most suitable fit for the adsorption kinetics of Cu(2+) was obtained with a pseudo-second-order model. It was determined that the adsorption capacity of the pristine clay is comparable with that of the activated carbon and the modification of clay with RL causes an increase in the adsorption rate due to the distribution of clay platelets in the solution.

  5. Surface reaction of Bacillus cereus biomass and its biosorption for lead and copper ions.

    PubMed

    Pan, Jian-hua; Liu, Rui-xia; Tang, Hong-xiao

    2007-01-01

    In this study, the surface chemical functional groups of Bacillus cereus biomass were identified by Fourier transform infrared (FTIR) analytical technique. It had been shown that the B. cereus cells mainly contained carboxyl, hydroxyl, phosphate, amino and amide functional groups. The potentiometric titration was conducted to explain the surface acid-base properties of aqueous B. cereus biomass. The computer program FITEQL 4.0 was used to perform the model calculations. The optimization results indicated that three sites-three pKas model, which assumed the cell surface to have three distinct types of surface organic functional groups based on the IR analysis results, simulated the experimental results very well. Moreover, batch adsorption experiments were performed to investigate biosorption behavior of Cu(II) and Pb(II) ions onto the biomass. Obviously, the adsorption equilibrium data for the two ions were reasonably described by typical Langmuir isotherm.

  6. Antioxidant properties of carnosine re-evaluated with oxidizing systems involving iron and copper ions.

    PubMed

    Mozdzan, Monika; Szemraj, Janusz; Rysz, Jacek; Nowak, Dariusz

    2005-05-01

    Carnosine has antioxidant properties and is efficient in the treatment of chemically-induced inflammatory lesions in animals. However, some studies question its biological significance as antioxidant and show lack of protection and even pro-oxidant effect of carnosine in systems containing nickel and iron ions. The ability of carnosine to: (1) reduce Fe(3+) into Fe(2+) ions; (2) protect deoxyribose from oxidation by Fe(2+)-, Fe(3+)-, and Cu(2+)-H(2)O(2)-EDTA systems; (3) protect DNA from damage caused by Cu(2+)-, and Fe(2+)-H(2)O(2)-ascorbate systems; (4) inhibit HClO- and H(2)O(2)-peroxidase-induced luminol dependent chemiluminescence was tested in vitro. At concentration 10 mM carnosine reduced 16.6+/-0.5 nmoles of Fe(3+) into Fe(2+) ions during 20 min. incubation and added to plasma significantly increased its ferric reducing ability. Inhibition of deoxyribose oxidation by 10 mM carnosine reached 56+/-5, 40+/-11 and 30+/-11% for systems containing Fe(2+), Fe(3+) and Cu(2+) ions, respectively. The damage to DNA was decreased by 84+/-9 and 61+/-14% when Cu(2+)-, and Fe(2+)-H(2)O(2)-ascorbate systems were applied. Combination of 10 mM histidine with alanine or histidine alone (but not alanine) enhanced 1.3 and 2.3 times (P<0.05) the DNA damage induced by Fe(2+)-H(2)O(2)-ascorbate. These amino acids added to 10 mM carnosine decreased 3.1-fold (P<0.05) its protective effect on DNA. Carnosine at 10 and 20 mM decreased by more than 90% light emission from both chemiluminescent systems. It is concluded that carnosine has significant antioxidant activity especially in the presence of transition metal ions. However, hydrolysis of carnosine with subsequent histidine release may be responsible for some pro-oxidant effects.

  7. Swelling and drug release behavior of poly(2-hydroxyethyl methacrylate/itaconic acid) copolymeric hydrogels obtained by gamma irradiation

    NASA Astrophysics Data System (ADS)

    Tomić, S. Lj.; Mićić, M. M.; Filipović, J. M.; Suljovrujić, E. H.

    2007-05-01

    The new copolymeric hydrogels based on 2-hydroxyethyl methacrylate (HEMA) and itaconic acid (IA) were prepared by gamma irradiation, in order to examine the potential use of these hydrogels in controlled drug release systems. The influence of IA content in the gel on the swelling characteristics and the releasing behavior of hydrogels, and the effect of different drugs, theophylline (TPH) and fenethylline hydrochloride (FE), on the releasing behavior of P(HEMA/IA) matrix were investigated in vitro. The diffusion exponents for swelling and drug release indicate that the mechanisms of buffer uptake and drug release are governed by Fickian diffusion. The swelling kinetics and, therefore, the release rate depends on the matrix swelling degree. The drug release was faster for copolymeric hydrogels with a higher content of itaconic acid. Furthermore, the drug release for TPH as model drug was faster due to a smaller molecular size and a weaker interaction of the TPH molecules with(in) the P(HEMA/IA) copolymeric networks.

  8. Regulation of feeding behavior and psychomotor activity by corticotropin-releasing hormone (CRH) in fish

    PubMed Central

    Matsuda, Kouhei

    2013-01-01

    Corticotropin-releasing hormone (CRH) is a hypothalamic neuropeptide belonging to a family of neuropeptides that includes urocortins, urotensin I, and sauvagine in vertebrates. CRH and urocortin act as anorexigenic factors for satiety regulation in fish. In a goldfish model, intracerebroventricular (ICV) administration of CRH has been shown to affect not only food intake, but also locomotor and psychomotor activities. In particular, CRH elicits anxiety-like behavior as an anxiogenic neuropeptide in goldfish, as is the case in rodents. This paper reviews current knowledge of CRH and its related peptides derived from studies of teleost fish, as representative non-mammals, focusing particularly on the role of the CRH system, and examines its significance from a comparative viewpoint. PMID:23754974

  9. Homing behavior of hippocampus and parahippocampus lesioned pigeons following short-distance releases.

    PubMed

    Bingman, V P; Mench, J A

    1990-11-30

    The avian hippocampal formation has been proposed to play a critical role in the neural regulation of a navigational system used by homing pigeons to locate their loft once in the familiar area near home. In support of this hypothesis, the homing performance of pigeons with target lesions of either the hippocampus or parahippocampus was found to be impaired compared to controls following releases of about 10 km. Further, radio tracking revealed that the in-flight behavior of the hippocampal lesioned homing pigeons was characterized by numerous direction changes and generally poor orientation with respect to the home loft. The results identify a local navigational impairment on the part of the hippocampal lesioned pigeons in the vicinity of the loft where landmark cues are thought to be important. Additionally, target lesions of the hippocampus or parahippocampus were found to be similarly effective in causing homing deficits.

  10. Multicarboxylic hyperbranched polyglycerol modified SBA-15 for the adsorption of cationic dyes and copper ions from aqueous media

    NASA Astrophysics Data System (ADS)

    Chen, Zhengji; Zhou, Li; Zhang, Faai; Yu, Chuanbai; Wei, Zhibo

    2012-04-01

    The aim of the present work was to investigate the potential of multicarboxylic hyperbranched polyglycerol (HPG) modified mesoporous SBA-15 (SBA/HPG-COOH) as adsorbent for the removal of cationic dyes or/and heavy metal ions from aqueous media. The SBA/HPG-COOH adsorbents can be facilely synthesized through two steps: in situ anionic ring-opening polymerization of glycidol and further modification of hydroxyl groups by succinic anhydride. The resulting SBA/HPG-COOH was characterized by means of FTIR, TGA, XRD, SEM and nitrogen adsorption-desorption isotherms. The results demonstrate that the SBA/HPG-COOH was successfully synthesized and the density of carboxylic groups on the SBA/HPG-COOH is calculated to be as high as 1.5 mmol/g, posing a powerful base for adsorbing cationic adsorbates. Four kinds of dyes and copper ions were chosen as representatives to investigate the adsorption ability of SBA/HPG-COOH. The SBA/HPG-COOH adsorbent showed quick adsorption rate, high adsorption capacity (e.g., its saturated adsorption capacity for methylene blue (MB) can reach 0.50 mmol/g, while for unmodified SBA-15 is lower than 0.05 mmol/g), and high selectivity for cationic adsorbates. The fitness of Langmuir adsorption model and pseudo second-order kinetics on describing the adsorption isotherm and kinetics of SBA/HPG-COOH for MB dye was examined, respectively. It is believed that this robust SBA/HPG-COOH adsorbent will find important application in removal of cationic adsorbates from aqueous solution.

  11. Lipid peroxidation and 4-hydroxy-2-nonenal formation by copper ion bound to amyloid-beta peptide.

    PubMed

    Hayashi, Takaaki; Shishido, Naomi; Nakayama, Kenji; Nunomura, Akihiko; Smith, Mark A; Perry, George; Nakamura, Masao

    2007-12-01

    The lipid peroxidation product 4-hydroxy-2-nonenal (HNE) is proposed to be a toxic factor in the pathogenesis of Alzheimer disease. The primary products of lipid peroxidation are phospholipid hydroperoxides, and degraded reactive aldehydes, such as HNE, are considered secondary peroxidation products. In this study, we investigated the role of amyloid-beta peptide (A beta) in the formation of phospholipid hydroperoxides and HNE by copper ion bound to A beta. The A beta1-42-Cu2+ (1:1 molar ratio) complex showed an activity to form phospholipid hydroperoxides from a phospholipid, 1-palmitoyl-2-linoleoyl phosphatidylcholine, through Cu2+ reduction in the presence of ascorbic acid. The phospholipid hydroperoxides were considered to be a racemic mixture of 9-hydroperoxide and 13-hydroperoxide of the linoleoyl residue. When Cu2+ was bound to 2 molar equivalents of A beta(1-42) (2 A beta1-42-Cu2+), lipid peroxidation was inhibited. HNE was generated from one of the phospholipid hydroperoxides, 1-palmitoyl-2-(13-hydroperoxy-cis-9, trans-11-octadecadienoyl) phosphatidylcholine (PLPC-OOH), by free Cu2+ in the presence of ascorbic acid through Cu2+ reduction and degradation of PLPC-OOH. HNE generation was markedly inhibited by equimolar concentrations of A beta(1-40) (92%) and A beta(1-42) (92%). However, A beta(1-42) binding 2 or 3 molar equivalents of Cu2+ (A beta1-42-2Cu2+, A beta1-42-3Cu2+) acted as a pro-oxidant to form HNE from PLPC-OOH. These findings suggest that, at moderate concentrations of copper, A beta acts primarily as an antioxidant to prevent Cu2+-catalyzed oxidation of biomolecules, but that, in the presence of excess copper, pro-oxidant complexes of A beta with Cu2+ are formed.

  12. Hydrophilic polymer drug from a derivative of salicylic acid: synthesis, controlled release studies and biological behavior.

    PubMed

    Rodríguez, Gema; Gallardo, Alberto; Fernández, Mar; Rebuelta, Mercedes; Buján, Julia; Bellón, Juan María; Honduvilla, Natalio G; Escudero, Cristina; San Román, Julio

    2004-06-25

    Hydrophilic polymeric drugs bearing "Triflusal" (4-trifluoromethylsalicylic acid), a drug widely used as antithrombogenic agent (Disgren), have been prepared by free radical copolymerization of methacryloyloxyethyl [2-(acetyloxy)-4-(trifluoromethyl)] benzoate (HTRF) and N,N'-dimethylacrylamide (DMA). The reactivity ratios of both monomers have been determined by 1H NMR spectra by applying non-linear least square treatments to the copolymerization equation (terminal model), and the kinetic parameters obtained indicated that the microstructure of copolymer chains is homogeneous, with a random distribution of the active HTRF units along the copolymer chains. That means that for the copolymer system THDMA22 used in this work, HTRF units are mainly isolated in relatively long DMA sequences. Therefore, in this structure the intramolecular interactions between adjacent HTRF units are negligible. Release of Triflusal from THDMA22 has been studied in vitro using buffered solutions at pH = 2, 7.4 and 10 and 37 degrees C. The system showed an interesting pseudo-zero order release profile at pH = 7.4 during several months. It has been also evaluated the pharmacological activity and the behavior of the system in contact with biological media. In this sense, we have carried out some in vitro studies about the antiaggregant properties and biocompatibility of THDMA22. Results demonstrate that this copolymer inhibits platelet aggregation in its macromolecular form and presents a good biocompatibility with Human Osteoblastic Cells (HOS).

  13. Shockless compression and release behavior of beryllium to 110 GPa

    SciTech Connect

    Brown, J. L.; Knudson, M. D.; Alexander, C. S.; Asay, J. R.

    2014-07-21

    A magnetohydrodynamic loading technique was used to shocklessly compress beryllium to peak longitudinal stresses of 19–110 GPa and, subsequently, unload in order to determine both the compressive response and also the shear stress supported upon release. Loading strain rates were on the order of 10{sup 6 }s{sup −1}, while the unloading rates were nearly constant at 3 × 10{sup 5 }s{sup −1}. Velocimetry was used to monitor the ramp and release behavior of a beryllium/lithium fluoride window interface. After applying window corrections to infer in situ beryllium velocities, a Lagrangian analysis was employed to determine the material response. The Lagrangian wavespeed-particle velocity response is integrated to generate the stress-strain path, average change in shear stress over the elastic unloading, and estimates of the shear modulus at peak compression. These data are used to infer the pressure dependence of the flow strength at the unloading rate. Comparisons to several strength models reveal good agreement to 45 GPa, but the data indicate 20%–30% higher strength near 100 GPa.

  14. Synthesis of photoresponsive hybrid alginate hydrogel with photo-controlled release behavior.

    PubMed

    Chiang, Chien-Ying; Chu, Chih-Chien

    2015-03-30

    A photoresponsive hybrid alginate hydrogel was successfully prepared by Ca(2+)-mediated crosslinking reaction with a mixture of β-cyclodextrin-grafted alginate (β-CD-Alg) and diazobenzene-modified poly(ethylene glycol) (Az2-PEG). The water-soluble Az2-PEG exhibits efficient trans-to-cis isomerization of the terminal azobenzene moieties under UV-light irradiation and readily switched back to the initial trans state under visible light. Because of low affinity between β-CD and cis-Az, the host-guest inclusion complex formed by β-CD and trans-Az gradually dissociates under UV-light exposure. Accordingly, the bulk gel exhibits substantial photo-induced transformation in gel morphology by the appearance of significant comb-like cavities. This photosensitive behavior accompanied by the structural degradation enables the rapid release of entrapped dye molecules under UV light stimulus. Moreover, an incident light with higher power and mild acidic environment are capable of accelerating the photo-triggered release, thus allowing the potential applications toward acute wound healing.

  15. Dentate gyrus–CA3 glutamate release/NMDA transmission mediates behavioral despair and antidepressant-like responses to leptin

    PubMed Central

    Wang, Xuezhen; Zhang, Di; Lu, Xin-Yun

    2014-01-01

    Compelling evidence supports the important role of the glutamatergic system in the pathophysiology of major depression and also as a target for rapid-acting antidepressants. However, the functional role of glutamate release/transmission in behavioral processes related to depression and antidepressant efficacy remains to be elucidated. In this study, glutamate release and behavioral responses to tail suspension, a procedure commonly used for inducing behavioral despair, were simultaneously monitored in real time. The onset of tail suspension stress evoked a rapid increase in glutamate release in hippocampal field CA3, which declined gradually after its offset. Blockade of NMDA receptors by intra-CA3 infusion of MK-801, a non-competitive NMDA receptor antagonist, reversed behavioral despair. The CA3 was innervated by granule neurons expressing the leptin receptor (LepRb) in the dentate gyrus (DG), representing a subpopulation of granule neurons that were devoid of stress-induced activation. Leptin treatment dampened tail suspension-evoked glutamate release in CA3. On the other hand, intra-CA3 infusion of NMDA blocked the antidepressant-like effect of leptin in reversing behavioral despair in both the tail suspension and forced swim tests, which involved activation of Akt signaling in DG. Together, these results suggest that the DG-CA3 glutamatergic pathway is critical for mediating behavioral despair and antidepressant-like responses to leptin. PMID:25092243

  16. The influence of spray-drying parameters on phase behavior, drug distribution, and in vitro release of injectable microspheres for sustained release.

    PubMed

    Meeus, Joke; Lenaerts, Maité; Scurr, David J; Amssoms, Katie; Davies, Martyn C; Roberts, Clive J; Van Den Mooter, Guy

    2015-04-01

    For ternary solid dispersions, it is indispensable to characterize their structure, phase behavior, and the spatial distribution of the dispersed drug as this might influence the release profile and/or stability of these formulations. This study shows how formulation (feed concentration) and process (feed rate, inlet air temperature, and atomizing air pressure) parameters can influence the characteristics of ternary spray-dried solid dispersions. The microspheres considered here consist of a poly(lactic-co-glycolic acid) (PLGA) surface layer and an underlying polyvinylpyrrolidone (PVP) phase. A poorly soluble active pharmaceutical ingredient (API) was molecularly dispersed in this matrix. Differences were observed in component miscibility, phase heterogeneity, particle size, morphology, as well as API surface coverage for selected spray-drying parameters. Observed differences are likely because of changes in the droplet generation, evaporation, and thus particle formation processes. However, varying particle characteristics did not influence the drug release of the formulations studied, indicating the robustness of this approach to produce particles of consistent drug release characteristics. This is likely because of the fact that the release is dominated by diffusion from the PVP layer through pores in the PLGA surface layer and that observed differences in the latter have no influence on the release.

  17. Post-prison Release HIV-Risk Behaviors in a Randomized Trial of Methadone Treatment for Prisoners

    PubMed Central

    Wilson, Monique E.; Kinlock, Timothy W.; Gordon, Michael S.; O’Grady, Kevin E.; Schwartz, Robert P.

    2012-01-01

    Background This secondary analysis examined the impact of methadone initiated in prison on post-release HIV risk behaviors. The parent study was a three-group randomized clinical trial in which participants received drug abuse counseling in prison and were randomly assigned to: (1) passive referral to substance abuse treatment upon release; (2) guaranteed methadone treatment admission upon release; and (3) methadone in prison and guaranteed continuation of methadone upon release. Methods Participants were 211 adult males with pre-incarceration histories of opiate dependence. The AIDS Risk Assessment was administered at baseline (in prison) and at 1-, 3-, 6-, and 12-months post-release. Data were analyzed for the entire sample (N = 211) as well as the subsamples who reported injecting drugs in the 30 days prior to incarceration (n = 131) and who reported having unprotected sex in that time frame (n = 144) using generalized linear mixed model on an intent-to-treat basis. Results There were no significant changes in sex- or drug-risk by Condition over Time. There were significant Time and Condition main effects for the total sample as well as the injector subsample for drug-risk behaviors. There were no significant Condition main effects for HIV sex–risk behaviors, but there were significant Time main effects. Conclusions Methadone initiated in prison or immediately post-release is associated with reduced HIV drug-risk compared to counseling in prison without methadone and passive referral to treatment at release. Participation in several drug- and sex-risk behaviors also showed significant declines during the post-release time periods. PMID:22882399

  18. A comparison of behavior for two cohorts of captive-reared greater sandhill cranes released in northern Arizona

    USGS Publications Warehouse

    Mummert, D.P.; Chambers, C.L.; Ellis, D.H.

    2001-01-01

    To determine how the behavior of greater sandhill cranes (Grus canadensis tabida) changes according to time of year, time of day, and number of days after release, we observed the activities of 2 groups of captive-reared greater sandhill cranes at Mormon Lake, northern Arizona. The behaviors we compared were alert, loafing, sleeping, foraging, preening, locomotion, and other. We found costume-reared subadult greater sandhill cranes that were established at the study site for a year spent more time foraging and being alert towards predators than parent-reared juvenile greater sandhill cranes that were recently released from captivity. We also found that with time juvenile sandhill cranes were increasingly alert and spent less time loafing. It appeared that captive-reared juvenile sandhill cranes learn behavior important for survival from previously released captive-reared cranes.

  19. Self-soothing behaviors with particular reference to oxytocin release induced by non-noxious sensory stimulation.

    PubMed

    Uvnäs-Moberg, Kerstin; Handlin, Linda; Petersson, Maria

    2014-01-01

    Oxytocin, a hypothalamic nonapeptide, is linked to increased levels of social interaction, well-being and anti-stress effects. The effects of oxytocin that is released by sensory stimulation during different kinds of interactive behaviors are often underestimated or even forgotten. In fact, many of the positive effects caused during interaction, such a wellbeing, stress reduction and even health promotion, are indeed linked to oxytocin released in response to activation of various types of sensory nerves. Oxytocin is released in response to activation of sensory nerves during labor, breastfeeding and sexual activity. In addition oxytocin is released in response to low intensity stimulation of the skin, e.g., in response to touch, stroking, warm temperature, etc. Consequently oxytocin is not only released during interaction between mothers and infants, but also during positive interaction between adults or between humans and animals. Finally oxytocin is also released in response to suckling and food intake. Oxytocin released in the brain in response to sensory stimulation as a consequence of these types of interactive behaviors, contributes to every day wellbeing and ability to handle stress. Food intake or sex may be used or even abused to achieve oxytocin-linked wellbeing and stress relief to compensate for lack of good relationships or when the levels of anxiety are high. The present review article will summarize the role played by oxytocin released by sensory (in particular somatosensory) stimulation, during various kinds of interactive behaviors. Also the fact that the anti-stress effects of oxytocin are particularly strong when oxytocin is released in response to "low intensity" stimulation of the skin will be highlighted.

  20. Self-soothing behaviors with particular reference to oxytocin release induced by non-noxious sensory stimulation

    PubMed Central

    Uvnäs-Moberg, Kerstin; Handlin, Linda; Petersson, Maria

    2015-01-01

    Oxytocin, a hypothalamic nonapeptide, is linked to increased levels of social interaction, well-being and anti-stress effects. The effects of oxytocin that is released by sensory stimulation during different kinds of interactive behaviors are often underestimated or even forgotten. In fact, many of the positive effects caused during interaction, such a wellbeing, stress reduction and even health promotion, are indeed linked to oxytocin released in response to activation of various types of sensory nerves. Oxytocin is released in response to activation of sensory nerves during labor, breastfeeding and sexual activity. In addition oxytocin is released in response to low intensity stimulation of the skin, e.g., in response to touch, stroking, warm temperature, etc. Consequently oxytocin is not only released during interaction between mothers and infants, but also during positive interaction between adults or between humans and animals. Finally oxytocin is also released in response to suckling and food intake. Oxytocin released in the brain in response to sensory stimulation as a consequence of these types of interactive behaviors, contributes to every day wellbeing and ability to handle stress. Food intake or sex may be used or even abused to achieve oxytocin-linked wellbeing and stress relief to compensate for lack of good relationships or when the levels of anxiety are high. The present review article will summarize the role played by oxytocin released by sensory (in particular somatosensory) stimulation, during various kinds of interactive behaviors. Also the fact that the anti-stress effects of oxytocin are particularly strong when oxytocin is released in response to “low intensity” stimulation of the skin will be highlighted. PMID:25628581

  1. Brain Genomics Superstruct Project initial data release with structural, functional, and behavioral measures

    PubMed Central

    Holmes, Avram J.; Hollinshead, Marisa O.; O’Keefe, Timothy M.; Petrov, Victor I.; Fariello, Gabriele R.; Wald, Lawrence L.; Fischl, Bruce; Rosen, Bruce R.; Mair, Ross W.; Roffman, Joshua L.; Smoller, Jordan W.; Buckner, Randy L.

    2015-01-01

    The goal of the Brain Genomics Superstruct Project (GSP) is to enable large-scale exploration of the links between brain function, behavior, and ultimately genetic variation. To provide the broader scientific community data to probe these associations, a repository of structural and functional magnetic resonance imaging (MRI) scans linked to genetic information was constructed from a sample of healthy individuals. The initial release, detailed in the present manuscript, encompasses quality screened cross-sectional data from 1,570 participants ages 18 to 35 years who were scanned with MRI and completed demographic and health questionnaires. Personality and cognitive measures were obtained on a subset of participants. Each dataset contains a T1-weighted structural MRI scan and either one (n=1,570) or two (n=1,139) resting state functional MRI scans. Test-retest reliability datasets are included from 69 participants scanned within six months of their initial visit. For the majority of participants self-report behavioral and cognitive measures are included (n=926 and n=892 respectively). Analyses of data quality, structure, function, personality, and cognition are presented to demonstrate the dataset’s utility. PMID:26175908

  2. Heparin-mimetic polyurethane hydrogels with anticoagulant, tunable mechanical property and controllable drug releasing behavior.

    PubMed

    Chen, Yuan; Wang, Rui; Wang, Yonghui; Zhao, Weifeng; Sun, Shudong; Zhao, Changsheng

    2017-05-01

    In the present study, novel heparin-mimetic polyurethane hydrogels were prepared by introducing chemical crosslinked sulfated konjac glucomannan (SKGM). Scanning electron microscopy (SEM) results indicated that the introduction of SKGM and the increase of the molecular weight of diol segments could enlarge the pore sizes of the hydrogels. The swelling behavior corresponded with the SEM results, and the hydrogels could absorb more water after the modification. The modification also led to an improvement in the mechanical property. Meanwhile, the SKGM and the modified polyurethane hydrogels showed excellent hemocompatibility. The thromboplastin time of SKGM could reach up to 182.9s. Gentamycin sulfate (GS) was used as a model drug to be loaded into the hydrogels, and the loading amount was increased ca. 50% after the introduction of SKGM, thus resulting in high bactericidal efficiency. The results indicated that the introduction of SKGM and the alternation in the diol's molecular weight bestowed polyurethane hydrogels with promising properties of integrated blood-compatibility, mechanical properties and drug loading-releasing behavior. Therefore, the heparin-mimetic multifunctional polyurethane hydrogels have great potential to be used in biomedical applications.

  3. Targeted mutations of the corticotropin-releasing factor system: effects on physiology and behavior.

    PubMed

    Contarino, A; Gold, L H

    2002-01-01

    Genetic modifications of the genes that encode proteins integral to the corticotropin-releasing factor (CRF) system have been employed in the creation of mutant mice that serve as tools for studying the role of this neuropeptide in regulated and dysregulated behaviors and physiology. Overexpression of the CRF peptide and CRF binding protein as well as deletion of the peptide, binding protein, and both known receptors has been achieved and these mouse models have been characterized for anatomical, neuroendocrine, and behavioral sequelae. The profile of results, consistent with current knowledge of CRF function from more traditional assays, indicates that enhancement of CRF function is associated with an activation of the hypothalamic-pituitary-adrenal axis, an anxious phenotype, alterations in cognitive performance and reductions in feeding. In general, blockade of CRF function produces the opposite effects. Genetic mouse models allow further analysis of specific elements in the CRF circuitry for which more traditional tools have not existed. These animal models are valuable for increasing our understanding of the underlying pathology associated with a variety of psychiatric and neuroendocrine disorders and for the development and testing of novel treatment agents.

  4. Ca(2+) and OH(-) release of ceramsites containing anorthite and gehlenite prepared from waste lime mud.

    PubMed

    Qin, Juan; Yang, Chuanmeng; Cui, Chong; Huang, Jiantao; Hussain, Ahmad; Ma, Hailong

    2016-09-01

    Lime mud is a kind of solid waste in the papermaking industry, which has been a source of serious environmental pollution. Ceramsites containing anorthite and gehlenite were prepared from lime mud and fly ash through the solid state reaction method at 1050°C. The objective of this study was to explore the efficiency of Ca(2+) and OH(-) release and assess the phosphorus and copper ion removal performance of the ceramsites via batch experiments, X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results show that Ca(2+) and OH(-) were released from the ceramsites due to the dissolution of anorthite, gehlenite and available lime. It is also concluded that gehlenite had stronger capacity for Ca(2+) and OH(-) release compared with anorthite. The Ca(2+) release could be fit well by the Avrami kinetic model. Increases of porosity, dosage and temperature were associated with increases in the concentrations of Ca(2+) and OH(-) released. Under different conditions, the ceramsites could maintain aqueous solutions in alkaline conditions (pH=9.3-10.9) and the release of Ca(2+) was not affected. The removal rates of phosphorus and copper ions were as high as 96.88% and 96.81%, respectively. The final pH values of both phosphorus and copper ions solutions changed slightly. The reuse of lime mud in the form of ceramsites is an effective strategy.

  5. Conditional Release of Forensic Psychiatric Patients Consistent with or Contrary to Behavioral Experts' Recommendations in the Netherlands: Prevalence Rates, Patient Characteristics and Recidivism After Discharge from Conditional Release.

    PubMed

    Nagtegaal, Maria H; Boonmann, Cyril

    2016-03-01

    The present study examined a group of 447 Dutch forensic psychiatric patients on conditional release (CR). After a brief overview of the Dutch CR system for forensic psychiatric patients is presented, two sets of factors were studied: factors associated with behavioral experts' recommendations on CR readiness (prevalence rates of recommendations in contrast to or consistent with the judge's decision on CR, written vs. oral recommendations and consensus among parties); and characteristics of forensic psychiatric patients on CR imposed consistent with or contrary to behavioral experts' recommendations (i.e., demographic variables, psychopathology, judicial background and outcomes of violent behavior). Patients on CR consistent with or contrary to the behavioral experts' recommendations did not differ in demographic background variables and psychopathology. Patients on CR contrary to the behavioral experts' recommendations, however, had more prior convictions, and their index offense more often included a sex offense and a property offense (with or without violence) as compared to patients on CR consistent with the behavioral experts' recommendations. In addition, decisions contrary to the behavioral experts' recommendations were more often reached after a 3-month continuation adjournment and after an appeal. Also, patients on CR contrary to the behavioral experts' recommendations were less often found to have been on trial leave before their CR. Finally, recidivism rates were found to be much higher for those on CR contrary to, as compared with those on CR consistent with the behavioral experts' recommendations. However, when corrected for other well-known static predictors of recidivism, this significant difference was no longer prevalent. The implications for evaluators' CR readiness reports and lessons that may be learned from the Dutch forensic psychiatric CR system are discussed. Copyright © 2016 John Wiley & Sons, Ltd.

  6. EFFECT OF LASER LIGHT ON MATTER. LASER PLASMAS: Spectra of multiply charged nickel and copper ions in an X-pinch plasma

    NASA Astrophysics Data System (ADS)

    Mingaleev, A. R.; Pikuz, S. A.; Romanova, V. M.; Shelkovenko, T. A.; Faenov, A. Ya; Érmatov, Sh A.; Nilsen, J.

    1993-05-01

    The L spectra of Ni and Cu ions produced in an X-pinch plasma have been recorded. A fast-optics Johann spectrograph and detection with spatial resolution were used to observe these spectra both in the hot, dense plasma and in the relatively cold recombining plasma expanding outward from the "hot spot." The wavelengths of a number of spectral lines of multiply charged nickel and copper ions were measured with relative error Δλ/λ ~ 10-4. A number of new lines of Na-like satellite lines were identified in the spectra of these ions.

  7. Release behavior and formation mechanism of polycyclic aromatic hydrocarbons during coal pyrolysis.

    PubMed

    Gao, Meiqi; Wang, Yulong; Dong, Jie; Li, Fan; Xie, Kechang

    2016-09-01

    Polycyclic aromatic hydrocarbons (PAHs) are major environmental pollutants. They have attracted considerable attention due to their severe potential carcinogenic, mutagenic and genotoxic effects on human health. In this study, five different rank coals from China were pyrolyzed using pyro-probe CDS 5250 and the release behavior of 16 PAHs under different pyrolysis conditions were studied by Gas Chromatography-Mass Spectrometer (GC-MS). The structural characteristics of the five coals were determined by Cross-Polarization/Magic Angle Spinning Carbon-13 Nuclear Magnetic Resonance (CP/MAS (13)C NMR) spectroscopy, and then the factors influencing the formation of PAHs during coal pyrolysis were discussed together with the coal structural data. It was shown that the amount of PAHs generated during coal pyrolysis was largely related to coal rank and followed the order of medium metamorphic coal > low metamorphic coal > high metamorphic coal. The amount of total PAHs varied as the temperature was increased from 400 °C to 1200 °C, which showed a trend of first increasing and then decreasing, with the maximum value at 800 °C. Moreover, the species of PAHs released varied with pyrolysis temperatures. When the temperature was lower than 800 °C, the small ring PAHs were the most abundant, while the proportion of heavy rings increased at higher temperature. The results indicate that the formation of PAHs during coal pyrolysis depends on the structure of the coal. The species and amounts of PAHs generated during coal pyrolysis are closely related to the contents of protonated aromatic carbons and bridging ring junction aromatic carbons present in the coal structure.

  8. Reduction of the copper ion to its metal and clusters in alcoholic media: A radiation chemical study

    NASA Astrophysics Data System (ADS)

    Dey, G. R.

    2005-10-01

    Reduction of Cu 2+ ions with and without I - as a ligand was studied in N 2-purged alcoholic solutions by pulse radiolysis. In the absence of iodide ion, the initial rate constant for e -sol reaction with Cu 2+ was determined following the decay of solvated electrons in different alcohols; kbimol values are in the range of 0.8-1.1×10 10 dm 3 mol -1 s -1. In the presence of 10 -3 mol dm -3 KI, the respective kbimol remained almost same. Generally, on reduction, Cu(II) ion changes to Cu(I) ion initially and later it produces metallic copper (Cu°), and the stability of these intermediates depends on the conditions of the matrix. In the presence of I -, Copper ions such as Cu(II) or Cu(I) ions get reduced to metallic copper (Cu°) having initial absorption around 740 and below 400 nm. Later, at 100 μs time after the electron pulse, it gets transformed into a nanoparticle with an absorption band at 580 nm. Such formation of copper nanoparticle was observed only in 2-propanolic medium in the presence of iodide ions. During γ-radiolysis of N 2-purged 1.5×10 -4 CuSO 4 solutions in 2-propanol, reddish pink colored copper nanoparticles were formed, which are quite similar to those reported earlier in aqueous solution. But, in the presence of I - (2-propanolic solutions), such phenomenon was not noticed on γ-radiolysis. Interestingly, the formation of copper nanoparticle was observed also in the reactions of copper (II) ions with alcohol radicals formed during γ-radiolysis in N 2O-purged system, where e -sol were scavenged by N 2O. The nanoparticles generated both in N 2 and N 2O-purged alcoholic systems, viz. methanol, ethanol and 2-propanol, were found to be oxygen sensitive. The contradictory results from pulse and γ-radiolysis studies in the presence and absence of iodide ions are explained to account for the nanoparticle generation.

  9. Release behavior of diethylhexyl phthalate from the polyvinyl-chloride tubing used for intravenous administration and the plasticized PVC membrane.

    PubMed

    Takehisa, Hanawa; Naoko, Endoh; Masahiko, Suzuki; Katsuhide, Terada; Moriyuki, Ohkuma; Keizoh, Sakuta; Mutsuko, Tanaka; Kenji, Kawano; Shin'ichiro, Nakajima; Toshio, Oguchi

    2005-06-13

    The release behavior of diethylhexyl phthalate (DEHP) from polyvinyl-chloride (PVC) tubing, which composes materials in an intravenous administration set, was investigated using polysorbate 80 (Tween 80) aqueous solutions. When Tween 80 solution was circulated in PVC tubing, the amount of DEHP released increased with increasing circulation velocity and temperature. In order to clarify the effect of temperature on the release behavior of DEHP, PVC films containing varying amounts of DEHP were mounted on a cylindrical shaft and rotated at 5 and 40 degrees C. The cumulative amount of DEHP released increased with an increase in temperature, the diffusion coefficients [Dx10(-10) cm2 min-1] at 5 and 40 degrees C were 9.1 and 156.0, respectively. The glass transition temperature (Tg) of PVC films decreased with an increase in DEHP in the PVC film, as measured by differential scanning calorimeter (DSC) and release of DEHP occurred at temperatures above Tg. These results indicate that the release of DEHP from PVC tubing is closely associated with the state of the PVC and is related to diffusion of DEHP throughout the PVC.

  10. Cytotoxicity and drug release behavior of PNIPAM grafted on silica-coated iron oxide nanoparticles

    NASA Astrophysics Data System (ADS)

    Lien, Yi-Hsin; Wu, Tzong-Ming; Wu, Jhao-Huei; Liao, Jiunn-Wang

    2011-10-01

    The nanoparticles containing thermosensitive and magnetic properties were investigated for their potential use as a novel drug carrier for targeted and controlled release drug delivery system. These thermosensitive and magnetic nanoparticles were prepared by grafting thermosensitive poly ( N-isopropylacrylamide) (PNIPAM) on the surface of silica (SiO2)-coated Fe3O4 nanoparticles with the particle size of 18.8 ± 1.6 nm. Adsorption and desorption behavior of bovine serum albumin (BSA) on the surface of PNIPAM-grafted SiO2/Fe3O4 nanoparticles was studied, and the results indicated that these nanoparticles were able to absorb protein at temperature above the lower critical solution temperature (LCST) and to be desorbed below the LCST. Cytotoxicity studies conducted on Chinese hamster ovary (CHO-K1) cells using methyl tetrazolium (MTT) assays revealed that cell viability of 1 mg/mL PNIPAM-grafted nanoparticles was slightly decreased after 24 h of incubation as compared to the lower concentration of nanoparticles. Furthermore, the concentration of 0.5 mg/mL PNIPAM-grafted nanoparticles was totally biocompatible for 48 h, but had low cytotoxicity after 72 h of incubation. These PNIPAM-grafted nanoparticles did not induce morphological change in their cellularity after exposure for 24 and 108 h. These results demonstrate that PNIPAM-grafted nanoparticles are biocompatible and have potential use as drug carriers.

  11. Impact of pore characteristics of silica materials on loading capacity and release behavior of ibuprofen.

    PubMed

    Numpilai, Thanapha; Muenmee, Suthaporn; Witoon, Thongthai

    2016-02-01

    Impact of pore characteristics of porous silica supports on loading capacity and release behavior of ibuprofen was investigated. The porous silica materials and ibuprofen-loaded porous silica materials were thoroughly characterized by N2-sorption, thermal gravimetric and derivative weight analyses (TG-DTW), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscope (SEM), transmission electron microscope (TEM) to determine the physical properties of materials, amount of ibuprofen adsorbed and position of ibuprofen. The detailed characterization reveals that the ibuprofen molecules adsorbed inside the mesopores. Increasing the mesopore size from 5nm to 10nm increased the ibuprofen loading from 0.74 to 0.85mmol/g, respectively. Incorporation of macropore into the structure of porous silica materials enhanced the ibuprofen loading capacity of 11.8-20.3%. The ibuprofen-loaded bimodal meso-macroporous silica materials exhibited the highest dissolution of 92wt.% within an hour. The ibuprofen particles deposited on the external surface of the porous silica materials showed a lower dissolution rate than the ibuprofen adsorbed inside the mesopores due to the formation of ibuprofen crystalline.

  12. [Effect of copper ions on spatial density of NO-synthase-positive cells in the intestine of the mussel Crenomytilus grayanus (Mollusca: Bivalvia: Mytilidae) a histochemical study].

    PubMed

    Pimenova, E A

    2010-01-01

    By the histochemical method of detection of NADPH-diaphorase (NADPH-d) (EC 1.6.99.1) the state of nitroxidergic enteric nervous system of the mussel Crenomytilus grayanus was studied under conditions of an increased copper concentration in water. Under the action of copper ions the density of distribution of NADPH-d-positive cells has been established to be changed as compared with control throughout 28 days. A sharp rise of proportion of the labeled cells and their enzyme activity was noted after one day of the experiment. The labeled bipolar cells were of dark blue color and were located within the epithelium. There were revealed numerous nerve fibers penetrating the intestinal epithelium throughout its entire length as well as bipolar nerve cells in epithelium of the minor typhlosole and of crystalline style sac; in control molluscs the NADPH-d-positive cells in these parts were absent. After 7 days the difference between control and experimental decreased and remained at this level after 14 days, while after 21 days of exposition the proportion of labeled cells in the experimental mussels was lower than in control, but increased again after 28 days. It is suggested that nitric oxide is an important protective factor of the intestinal epithelium of the mussel C. grayanus and participates in adaptation of this mollusc to action of the elevated concentration of copper ions in water.

  13. Evaluation of the possible role of copper ions in drinking water in the pathogenesis of oral submucous fibrosis: a pilot study.

    PubMed

    Arakeri, Gururaj; Patil, Shekhar Gowda; Ramesh, D N S V; Hunasgi, Santosh; Brennan, Peter A

    2014-01-01

    We aimed to investigate the concentration of copper ions in drinking water and to assess whether copper has a role in the pathogenesis of oral submucous fibrosis (OSMF). We studied 50 patients with clinically and histologically diagnosed OSMF from the Yadgir district of Karnataka in India. Fifty healthy people matched for age and sex were used as controls. In both groups concentrations of copper ions in serum, saliva, and home drinking water were measured using atomic absorption spectroscopy and intelligent nephelometry technology. Serum ceruloplasmin concentrations were also estimated in both groups. The mean (SD) concentration of copper in the home drinking water of patients with OSMF was significantly higher (764.3 (445.9)μmol/L) than in the controls (305.7 (318.5)μmol/L) (p<0.001). Patients with OSMF also had a significantly higher copper concentrations in serum and saliva, and serum ceruloplasmin than controls (p<0.001). For the first time these data have shown a positive association between copper concentrations in home drinking water and OSMF. It raises the possibility that increased copper in drinking water contributes to the development of OSMF, and adds to that ingested when areca nut is chewed.

  14. A novel fluorescent probe for copper ions based on polymer-modified CdSe/CdS core/shell quantum dots.

    PubMed

    Cao, Zhong; Gu, Zheng; Zeng, Ju-Lan; Liu, Jin-Hua; Deng, Qin; Fan, Jun-Bing; Xiang, Jian-Nan

    2011-01-01

    Quantum dots (QDs) have become one of the most attractive fields of current research because of their unique optical properties. Novel copper-sensitive fluorescent fluoroionophores based on CdSe/CdS core/shell QDs modified with a polymer of MAO-mPEG were synthesized and characterized in the present work. A pH of 6.47 was optimally selected for measurements. By modifying QDs with MAO-mPEG, significant aqueous fluorescence quenching was observed upon binding with copper ions involving both reduced and oxidized environments, indicating great sensitivity and specificity for copper-ion sensing. No significant interfering effects from other metal ions, such as Ag(+), Al(3+), Ba(2+), Ca(2+), Cd(2+), Co(2+), Cr(3+), Fe(2+), Fe(3+), Hg(2+), K(+), Mg(2+), Mn(2+), Na(+), Ni(2+), Pb(2+), Sn(2+), and Zn(2+), were observed. The linear response range for Cu(2+) was found to be 0.01-0.50 µM, and the limit of detection was evaluated to be 16 nM. The proposed method demonstrated improved sensitivity and selectivity characteristics for Cu(II) determinations based on CdSe/CdS core/shell QDs modified with MAO-mPEG by using a typical liquid-phase quenching assay, showing its potential application to multiplex sensing of different analytes through distinct ligand conjugation and functionalization of individual fluorophores.

  15. Release behavior and kinetic evaluation of berberine hydrochloride from ethyl cellulose/chitosan microspheres

    NASA Astrophysics Data System (ADS)

    Zhou, Hui-Yun; Cao, Pei-Pei; Zhao, Jie; Wang, Zhi-Ying; Li, Jun-Bo; Zhang, Fa-Liang

    2014-12-01

    Novel ethyl cellulose/chitosan microspheres (ECCMs) were prepared by the method of w/o/w emulsion and solvent evaporation. The microspheres were spherical, adhesive, and aggregated loosely with a size not bigger than 5 μm. The drug loading efficiency of berberine hydrochloride (BH) loaded in microspheres were affected by chitosan (CS) concentration, EC concentration and the volume ratio of V(CS)/ V(EC). ECCMs prepared had sustained release efficiency on BH which was changed with different preparation parameters. In addition, the pH value of release media had obvious effect on the release character of ECCMs. The release rate of BH from sample B was only a little more than 30% in diluted hydrochloric acid (dHCl) and that was almost 90% in PBS during 24 h. Furthermore, the drug release data were fitted to different kinetic models to analyze the release kinetics and the mechanism from the microspheres. The released results of BH indicated that ECCMs exhibited non-Fickian diffusion mechanism in dHCl and diffusion-controlled drug release based on Fickian diffusion in PBS. So the ECCMs might be an ideal sustained release system especially in dHCl and the drug release was governed by both diffusion of the drug and dissolution of the polymeric network.

  16. Impact of implant composition of twin-screw extruded lipid implants on the release behavior.

    PubMed

    Even, Marie-Paule; Bobbala, Sharan; Kooi, Kok Liang; Hook, Sarah; Winter, Gerhard; Engert, Julia

    2015-09-30

    The development of vaccine delivery systems that will remove or reduce the need for repeated dosing has led to the investigation of sustained release systems. In this context, the duration of antigen release is of great importance as is the requirement for concomitant adjuvant release. In this work, lipid implants consisting of cholesterol (CHOL), soybean lecithin, Dynasan 114 (D114), the model antigen ovalbumin (OVA) and the adjuvant Quil-A (QA) were produced by twin-screw extrusion. The release of antigen and adjuvant was investigated in vitro and we observed complete OVA release over a period of 7 days while QA was released in a linear fashion over a period of up to 12 days. In order to extend OVA release, lipid implants were subjected to post-extrusion curing at 45-55°C. The OVA release could be extended to up to 14 days. Furthermore the influence of the implant composition on the release of the model antigen was investigated. It was shown that the percentage of cholesterol in particular plays an important role in modulating release.

  17. IDENTIFICATION OF PHARMACEUTICAL EXCIPIENT BEHAVIOR OF CHICKPEA (CICER ARIETINUM) STARCH IN GLICLAZIDE IMMEDIATE RELEASE TABLETS.

    PubMed

    Meka, Venkata Srikanth; Yee, Phung; Sheshala, Ravi

    2016-01-01

    In the past few years, there are number of researchers carrying out their research on the excipients derived from polysaccharides and some of these researches show that natural excipients are comparable and can serve as an alternative to the synthetic excipients. Hence, the objectives of this research are to characterize the naturally sourced chickpea starch powder and to study the pharmaceutical excipient behavior of chickpea starch in gliclazide immediate release (IR) tablets. In this research, the binding properties of chickpea starch were compared to that of povidone, whereas the disintegrant properties of chickpea starch were compared to those of crospovidone, croscarmellose sodium and sodium starch glycolate. Flow property of chickpea starch was assessed with the measurement of bulk density, tapped density, compressibility index and angle of repose. Calibration curve for gliclazide in phosphate buffer pH 7.4 was developed. Gliclazide IR tablets were then produced with direct compression method. Physicochemical characteristics of the tablets, including thickness, tablet weight uniformity, hardness, disintegration time and friability were evaluated. Then, in vitro dissolution studies were performed by following United States Pharmacopeia (USP) dissolution method. The dissolution results were analyzed and compared with t30, t50, dissolution efficiency (DE). Lastly, drug-excipient compatibility studies, including Fourier transform infrared (FTIR) spectroscopic analysis and differential scanning calorimetric (DSC) analysis were carried out. Fair flow property was observed in the chickpea starch powder. Furthermore, the tablets produced passed all the tests in physicochemical characteristics evaluation except hardness and disintegration test. Additionally, in vitro dissolution studies show that chickpea starch acted as a disintegrant instead of a binder in gliclazide IR tablets and its disintegrant properties were comparable to those of crospovidone, croscarmellose

  18. Development of polysaccharide gel-coated pellets for oral administration: swelling and release behavior of calcium pectinate gel.

    PubMed

    Sriamornsak, Pornsak; Kennedy, Ross A

    2007-09-28

    The aim of this study was to examine the effect of pellet size, pectin type, pectin concentration, and dissolution medium on the swelling and drug release behavior of spherical pellets containing theophylline and coated with 2 different calcium pectinates, using a multi-level factorial design approach. The spherical pellets were prepared by an extrusion-spheronization method and then coated with calcium pectinate using the diffusion-controlled interfacial complexation technique, which provides a defect-free and uniform coating on solid cores. Theophylline release from the pellets was slowed by the application of the coatings. The time to release 50% of the payload (ie, T50) in an acidic medium was approximately 7 minutes from uncoated small pellets and was 55 minutes after an amidated calcium pectinate coat was applied; a comparable coat on large pellets showed a T50 of 93 minutes. Drug release profiles of dry coated pellets showed a lag time (all less than 20 minutes) when the gel coat hydrated and swelled, followed by a zero-order release. It was found that the release rate was controlled by the pellet size, pectin type, pectin concentration, and dissolution medium.

  19. Juvenile hormone analog enhances calling behavior, mating success, and quantity of volatiles released by Anastrepha obliqua (Diptera: Tephritidae).

    PubMed

    Chacón-Benavente, Roxana; López-Guillen, Guillermo; Hernández, Emilio; Rojas, Julio C; Malo, Edi A

    2013-04-01

    The application of a juvenile hormone analog, methoprene, to newly emerged adult males reduced the time required for sexual maturation and enhanced mating success in several species of tephritid fruit flies. In this work, we investigated the effect of topical methoprene application on West Indian fruit fly, Anastrepha obliqua (Macquart), male calling, mating, and volatile release. Males treated with topical methoprene exhibited sexual maturation and reproductive behavior 2 d earlier when compared with control males treated with acetone. Methoprene-treated males began calling and mating at 4 d old, whereas control males did not call and mate until 6 d old. The gas chromotography-mass spectrometry analysis of volatiles showed that during calling A. obliqua males consistently released four compounds; three of them were identified as (Z)-3-nonenol, (Z,E)-α-farnesene, (E,E)-α-farnesene, and a fourth compound with the appearance of a farnesene isomer. Both treated and control males released the same compounds, although treated males started to release volatiles before that control males. The results are discussed in view of possible methoprene application with the aim of reducing costs in fly emergence and release facilities before eventual release of A. obliqua in the field, thus improving the sterile insect technique.

  20. Acute response of hypophysiotropic thyrotropin releasing hormone neurons and thyrotropin release to behavioral paradigms producing varying intensities of stress and physical activity.

    PubMed

    Gutiérrez-Mariscal, Mariana; Sánchez, Edith; García-Vázquez, Arlene; Rebolledo-Solleiro, Daniela; Charli, Jean-Louis; Joseph-Bravo, Patricia

    2012-11-10

    The activity of the hypothalamus-pituitary-thyroid (HPT) axis is essential for energy homeostasis and is differentially modulated by physical and by psychological stress. Contradictory effects of stressful behavioral paradigms on TSH or thyroid hormone release are due to type, length and controllability of the stressor. We hypothesized that an additional determinant of the activity of the HPT axis is the energy demand due to physical activity. We thus evaluated the response of thyrotropin releasing hormone (TRH) neurons of the hypothalamic paraventricular nucleus (PVN) in Wistar male rats submitted to the elevated plus maze (EPM), the open field test (OFT), or restraint, and sacrificed within 1h after test completion; the response to OFT was compared during light (L) or dark (D) phases. Locomotion and anxiety behaviors were similar if animals were tested in L or D phases but their relation to the biochemical parameters differed. All paradigms increased serum corticosterone concentration; the levels of corticotropin releasing hormone receptor 1 and of glucocorticoid receptor (GR) mRNAs in the PVN were enhanced after restraint or OFT-L. Levels of proTRH mRNA increased in the PVN after exposure to EPM-L or OFT-D; serum levels of thyrotropin (TSH) and T(4) only after OFT-D. In contrast, restraint decreased TRH mRNA and serum TSH levels, while it increased TRH content in the mediobasal hypothalamus, implying reduced release. Expression of proTRH in the PVN varied proportionally to the degree of locomotion in OFT-D, while inversely to anxiety in the EPM-L, and to corticosterone in EPM-L and OFT-D. TRH mRNA levels were analyzed by in situ hybridization in the rostral, middle and caudal zones of the PVN in response to OFT-D; they increased in the middle PVN, where most TRH hypophysiotropic neurons reside; levels correlated positively with the velocity attained in the periphery of the OF and negatively, with anxiety. Variations of serum TSH levels correlated positively with

  1. Clozapine and cocaine effects on dopamine and serotonin release in nucleus accumbens during psychostimulant behavior and withdrawal.

    PubMed

    Broderick, Patricia A; Hope, Omotola; Okonji, Catherine; Rahni, David N; Zhou, Yueping

    2004-01-01

    There is an increasing awareness that a psychosis, similar to that of schizophrenic psychosis, can be derived from cocaine addiction. Thus, the prototypical atypical antipsychotic medication, clozapine, a 5-HT(2)/DA(2) antagonist, was studied for its effects on cocaine-induced dopamine (DA) and serotonin (5-HT) release in nucleus accumbens (NAcc) of behaving male Sprague-Dawley laboratory rats with In Vivo Microvoltammetry, while animals' locomotor (forward ambulations), an A(10) behavior, was monitored at the same time with infrared photobeams. Release mechanisms for monoamines were determined by using a depolarization blocker, gamma-butyrolactone (gammaBL). BRODERICK PROBE microelectrodes selectively detected release of DA and 5-HT within seconds and sequentially in A(10) nerve terminals, NAcc. Acute and subacute studies were performed for each treatment group. Acute studies are defined as single injection of drug(s) after a stable baseline of each monoamine and locomotor behavior has been achieved. Subacute studies are defined as 24-h follow-up studies on each monoamine and locomotor behavior, in the same animal at which time, no further drug was administered. Results showed that (1) acute administration of cocaine (10 mg/kg ip) (n=5) significantly increased both DA and 5-HT release above baseline (P<.001) while locomotion was also significantly increased above baseline (P<.001). In subacute studies, DA release decreased significantly below baseline (P<.001) and significant decreases in 5-HT release occurred at the 15-min mark and at each time point during the second part of the hour (P<.05); the maximum decrease in 5-HT was 40% below baseline. Locomotor behavior, on the other hand, increased significantly above baseline (P<.05). (2) Acute administration of clozapine/cocaine (20 and 10 mg/kg ip, respectively; n=6) produced a significant block of the cocaine-induced increase in DA (P<.001) and 5-HT release (P<.001). Cocaine-induced locomotion was blocked

  2. Biodynamics of copper oxide nanoparticles and copper ions in an oligochaete - Part II: Subcellular distribution following sediment exposure.

    PubMed

    Thit, Amalie; Ramskov, Tina; Croteau, Marie-Noële; Selck, Henriette

    2016-11-01

    The use and likely incidental release of metal nanoparticles (NPs) is steadily increasing. Despite the increasing amount of published literature on metal NP toxicity in the aquatic environment, very little is known about the biological fate of NPs after sediment exposures. Here, we compare the bioavailability and subcellular distribution of copper oxide (CuO) NPs and aqueous Cu (Cu-Aq) in the sediment-dwelling worm Lumbriculus variegatus. Ten days (d) sediment exposure resulted in marginal Cu bioaccumulation in L. variegatus for both forms of Cu. Bioaccumulation was detected because isotopically enriched (65)Cu was used as a tracer. Neither burrowing behavior or survival was affected by the exposure. Once incorporated into tissue, Cu loss was negligible over 10 d of elimination in clean sediment (Cu elimination rate constants were not different from zero). With the exception of day 10, differences in bioaccumulation and subcellular distribution between Cu forms were either not detectable or marginal. After 10 d of exposure to Cu-Aq, the accumulated Cu was primarily partitioned in the subcellular fraction containing metallothionein-like proteins (MTLP, ≈40%) and cellular debris (CD, ≈30%). Cu concentrations in these fractions were significantly higher than in controls. For worms exposed to CuO NPs for 10 d, most of the accumulated Cu was partitioned in the CD fraction (≈40%), which was the only subcellular fraction where the Cu concentration was significantly higher than for the control group. Our results indicate that L. variegatus handle the two Cu forms differently. However, longer-term exposures are suggested in order to clearly highlight differences in the subcellular distribution of these two Cu forms.

  3. Biodynamics of copper oxide nanoparticles and copper ions in an oligochaete - Part II: Subcellular distribution following sediment exposure

    USGS Publications Warehouse

    Thit, Amalie; Ramskov, Tina; Croteau, Marie-Noele; Selck, Henriette

    2016-01-01

    The use and likely incidental release of metal nanoparticles (NPs) is steadily increasing. Despite the increasing amount of published literature on metal NP toxicity in the aquatic environment, very little is known about the biological fate of NPs after sediment exposures. Here, we compare the bioavailability and subcellular distribution of copper oxide (CuO) NPs and aqueous Cu (Cu-Aq) in the sediment-dwelling worm Lumbriculus variegatus. Ten days (d) sediment exposure resulted in marginal Cu bioaccumulation in L. variegatus for both forms of Cu. Bioaccumulation was detected because isotopically enriched 65Cu was used as a tracer. Neither burrowing behavior or survival was affected by the exposure. Once incorporated into tissue, Cu loss was negligible over 10 d of elimination in clean sediment (Cu elimination rate constants were not different from zero). With the exception of day 10, differences in bioaccumulation and subcellular distribution between Cu forms were either not detectable or marginal. After 10 d of exposure to Cu-Aq, the accumulated Cu was primarily partitioned in the subcellular fraction containing metallothionein-like proteins (MTLP, ≈40%) and cellular debris (CD, ≈30%). Cu concentrations in these fractions were significantly higher than in controls. For worms exposed to CuO NPs for 10 d, most of the accumulated Cu was partitioned in the CD fraction (≈40%), which was the only subcellular fraction where the Cu concentration was significantly higher than for the control group. Our results indicate that L. variegatus handle the two Cu forms differently. However, longer-term exposures are suggested in order to clearly highlight differences in the subcellular distribution of these two Cu forms.

  4. Many facets of the polyelectrolyte and oppositely charged colloidal particle complexation: counterion release and electrical conductivity behavior.

    PubMed

    Cametti, C; Truzzolillo, D

    2011-06-09

    The lateral correlated adsorption of polyions onto oppositely charged vesicles, leading to the formation of stable equilibrium clusters of mesoscopic size, is associated to the release of a fraction of counterions, initially condensed on the polyion chains. This ulterior release of counterions provokes an increase of the number of free ions, besides the ones due to the partial ionization of both charged particles and polyions, that can be appropriately monitored by means of electrical conductivity measurements of the whole system. We have investigated this behavior in a suspension of cationic vesicles made up by dioleoyl trimethyl ammonium propane (DOTAP) liposomial vesicles interacting with an anionic polyelectrolyte composed by polyacrylate sodium salt. This system has been in the past extensively studied by us by means of different experimental techniques, and its behavior has been sufficiently characterized, as far as hydrodynamic and electrical properties are concerned. In this note, we report on the dc electrical conductivity behavior during the whole aggregation process, from the single polyion-coated liposomal particles, to polyion-induced liposome clusters, to finally polyion-fully covered liposomes, in polyion excess conditions. We have evaluated the excess of released counterions on the basis of the standard theory of the electrical properties of aqueous charged solutions and compared this quantity with the one predicted by the lateral correlation adsorption model. The agreement is quite good, offering strong experimental evidence of the role played by the release of counterions in the aggregation process. Finally, we have considered a similar liposomial system, where the lateral correlation adsorption was inhibited by structural reasons, having replaced the polyion by a simple electrolyte, whose dissociated ions will adsorb randomly at the particle surface, rather than in a correlated manner. In this case, no counterion release upon complexation occurs

  5. The presence of traces of iron and copper ions during gamma-irradiation does not result in clear mutational hot spots in the lacI gene.

    PubMed

    Wijker, C A; Lafleur, M V

    1999-08-11

    Oxidative radicals, which are produced during ionizing irradiation of DNA in water, damage the DNA and may result in mutations, which are in general randomly distributed. Alternatively, the addition of transition metal ions, like iron or copper, to DNA in combination with H(2)O(2) and a reducing agent also results in the production of oxidative radicals. Due to binding of the transition metal ions to DNA, the production of these radicals is very local, and results in a mutational spectrum in which the mutations are not randomly distributed. If transition metal ions are complexed to the DNA during irradiation, and react with radiation-induced species such as hydrogen peroxide, site-specific formation of.OH radicals on these sites may occur, leading to the formation of mutational hot spots. This study examines the influence of the presence of traces of iron or copper ions during gamma-irradiation of plasmid DNA in water, on the possible formation of mutational hot spots in the lacI gene. Comparison of the mutational spectra, after irradiation in the presence or in the absence of transition metal ions, shows that there are indeed relatively more positions in the lacI gene where more than one mutation occurs, suggesting formation of mutational hot spots in the presence of transition metal ions. However, the appearance of these hot spots is rather weak. Although in all three mutational spectra G:C to A:T mutations are predominant, there are also some differences between the types of mutations in these spectra. These differences in mutational spectra might reflect the different preferences of iron and copper ions to bind specific sites in the DNA. Indeed, there appears to be a high association of mutations at CC or GG sites in the mutational spectrum in the presence of copper ions, confirming the observation that copper binds preferably at two adjacent guanines in the DNA. It can be concluded from this study that the presence of small amounts of transition metal ions

  6. Release behavior and bioefficacy of imazethapyr formulations based on biopolymeric hydrogels.

    PubMed

    Kumar, Vikas; Singh, Anupama; Das, T K; Sarkar, Dhruba Jyoti; Singh, Shashi Bala; Dhaka, Rashmi; Kumar, Anil

    2017-03-08

    Controlled release formulations of imazethapyr herbicide have been developed employing guar gum-g-cl-polyacrylate/bentonite clay hydrogel composite (GG-HG) and guar gum-g-cl-PNIPAm nano hydrogel (GG-NHG) as carriers, to assess the suitability of biopolymeric hydrogels as controlled herbicide release devices. The kinetics of imazethapyr release from the developed formulations was studied in water and it revealed that the developed formulations of imazethapyr behaved as slow release formulations as compared to commercial formulation. The calculated diffusion exponent (n) values showed that Fickian diffusion was the predominant mechanism of imazethapyr release from the developed formulations. Time for release of half of the loaded imazethapyr (t1/2) ranged between 0.06 and 4.8 days in case of GG-NHG and 4.4 and 12.6 days for the GG-HG formulations. Weed control index (WCI) of GG-HG and GG-NHG formulations was similar to that of the commercial formulation and the herbicidal effect was observed for relatively longer period. Guar gum-based biopolymeric hydrogels in both macro and nano particle size range can serve as potential carriers in developing slow release herbicide formulations.

  7. Release behavior of uranium in uranium mill tailings under environmental conditions.

    PubMed

    Liu, Bo; Peng, Tongjiang; Sun, Hongjuan; Yue, Huanjuan

    2017-02-28

    Uranium contamination is observed in sedimentary geochemical environments, but the geochemical and mineralogical processes that control uranium release from sediment are not fully appreciated. Identification of how sediments and water influence the release and migration of uranium is critical to improve the prevention of uranium contamination in soil and groundwater. To understand the process of uranium release and migration from uranium mill tailings under water chemistry conditions, uranium mill tailing samples from northwest China were investigated with batch leaching experiments. Results showed that water played an important role in uranium release from the tailing minerals. The uranium release was clearly influenced by contact time, liquid-solid ratio, particle size, and pH under water chemistry conditions. Longer contact time, higher liquid content, and extreme pH were all not conducive to the stabilization of uranium and accelerated the uranium release from the tailing mineral to the solution. The values of pH were found to significantly influence the extent and mechanisms of uranium release from minerals to water. Uranium release was monitored by a number of interactive processes, including dissolution of uranium-bearing minerals, uranium desorption from mineral surfaces, and formation of aqueous uranium complexes. Considering the impact of contact time, liquid-solid ratio, particle size, and pH on uranium release from uranium mill tailings, reducing the water content, decreasing the porosity of tailing dumps and controlling the pH of tailings were the key factors for prevention and management of environmental pollution in areas near uranium mines.

  8. Three-dimensional, two-species magnetohydrodynamic studies of the early time behaviors of the Combined Release and Radiation Effects Satellite G2 barium release

    SciTech Connect

    Xie, Lianghai Li, Lei; Wang, Jingdong; Zhang, Yiteng

    2014-04-15

    We present a three-dimensional, two-species (Ba{sup +} and H{sup +}) MHD model to study the early time behaviors of a barium release at about 1 R{sub E} like Combined Release and Radiation Effects Satellite G2, with emphasis placed on the three-dimensional evolution of the barium cloud and its effects on the ambient plasma environment. We find that the perturbations caused by the cloud are the combined results of the initial injection, the radial expansion, and the diamagnetic effect and propagate as fast MHD waves in the magnetosphere. In return, the transverse expansion and the cross-B motion of barium ions are constrained by the magnetic force, which lead to a field-aligned striation of ions and the decoupling of these ions from the neutrals. Our simulation shows the formation and collapse of the diamagnetic cavity in the barium cloud. The estimated time scale for the cavity evolution might be much shorter if photoionization time scale and field aligned expansion of barium ions are considered. In addition, our two species MHD simulation also finds the snowplow effect resulting from the momentum coupling between barium ions and background H{sup +}, which creates density hole and bumps in the background H{sup +} when barium ions expanding along the magnetic field lines.

  9. High loading fragrance encapsulation based on a polymer-blend: preparation and release behavior.

    PubMed

    Sansukcharearnpon, Aurapan; Wanichwecharungruang, Supason; Leepipatpaiboon, Natchanun; Kerdcharoen, Teerakiat; Arayachukeat, Sunatda

    2010-05-31

    The six fragrances, camphor, citronellal, eucalyptol, limonene, menthol and 4-tert-butylcyclohexyl acetate, which represent different chemical functionalities, were encapsulated with a polymer-blend of ethylcellulose (EC), hydroxypropyl methylcellulose (HPMC) and poly(vinyl alcohol) (PV(OH)) using solvent displacement (ethanol displaced by water). The process gave >or=40% fragrance loading capacity with >or=80% encapsulation efficiency at the fragrance to polymer weight ratio of 1:1 and at initial polymer concentrations of 2000-16,000 ppm and the obtained fragrance-encapsulated spheres showed hydrodynamic diameters of less than 450 nm. The release profile of the encapsulated fragrances, evaluated by both thermal gravimetric and electronic nose techniques, indicated different release characteristics amongst the six encapsulated fragrances. Limonene showed the fastest release with essentially no retention by the nanoparticles, while eucalyptol and menthol showed the slowest release.

  10. Measuring the dynamic compression and release behavior of rocks associated with HYDROPLUS (Part 2)

    SciTech Connect

    Furnish, M.D.

    1995-07-01

    Three sets of rock samples have been subjected to planar impact to characterize loading, Hugoniot and release responses. A slate form Pennsylvania was tested over the stress range of 5 GPa to 140 GPa. Phyllite from the Lupin Mine (Canada) was tested over the 14--50 GPa stress region. Finally, granite samples from the SHIST test site (New Mexico) were tested over the 10--20 GPa stress region. The granite tests included a transmitted-wave experiment at about 10 GPa. In 12 of the 13 tests, a reverse-ballistic configuration (optimized for Hugoniot and release measurements) was used. The remaining test (conducted on the granite) provided a transmitted waveform from which precursor, Hugoniot and release properties were obtained. Velocity interferometry (VISAR) was used as the primary diagnostic throughout. The slate data showed an unexpected inflection downward in the Hugoniot at around 8 GPa. The slate and granite showed release paths lying below the Hugoniot for lower stress levels (below {approx} 60 GPa), while the slate release paths were ``normal`` (above the Hugoniot) at higher stress levels. In addition, the granite releases were found to lie substantially below the Hugoniot in the 30--40 GPa region; this may be related to the quartz-stishovite transition. The present results are generally consistent with earlier work.

  11. Synthesis, characterization, and controlled release antibacterial behavior of antibiotic intercalated Mg–Al layered double hydroxides

    SciTech Connect

    Wang, Yi; Zhang, Dun

    2012-11-15

    Graphical abstract: The antibiotic anion released from Mg–Al LDHs provides a controlled release antibacterial activity against the growth of Micrococcus lysodeikticus in 3.5% NaCl solution. Highlights: ► Antibiotic anion intercalated LDHs were synthesized and characterized. ► The ion-exchange one is responsible for the release process. ► The diffusion through particle is the release rate limiting step. ► LDHs loaded with antibiotic anion have high antibacterial capabilities. -- Abstract: Antibiotic–inorganic clay composites including four antibiotic anions, namely, benzoate (BZ), succinate (SU), benzylpenicillin (BP), and ticarcillin (TC) anions, intercalated Mg–Al layered double hydroxides (LDHs) were synthesized via ion-exchange. Powder X-ray diffraction and Fourier transform infrared spectrum analyses showed the successful intercalation of antibiotic anion into the LDH interlayer. BZ and BP anions were accommodated in the interlayer region as a bilayer, whereas SU and TC anions were intercalated in a monolayer arrangement. Kinetic simulation of the release data indicated that ion-exchange was responsible for the release process, and the diffusion through the particles was the rate-limiting step. The antibacterial capabilities of LDHs loaded with antibiotic anion toward Micrococcus lysodeikticus growth were analyzed using a turbidimetric method. Significant high inhibition rate was observed when LDH nanohybrid was introduced in 3.5% NaCl solution. Therefore, this hybrid material may be applied as nanocontainer in active antifouling coating for marine equipment.

  12. Recreational anglers' attitudes, beliefs, and behaviors related to catch-and-release practices of Pacific salmon in British Columbia.

    PubMed

    Nguyen, Vivian M; Rudd, Murray A; Hinch, Scott G; Cooke, Steven J

    2013-10-15

    The fate of captured and released fish in recreational fisheries depends in large part on fisher handling and behavior. As such, there is a need for promoting adoption of responsible fishing practices. We interviewed recreational sockeye salmon anglers in the lower Fraser River, British Columbia, to assess their awareness of responsible fishing practices and identify gaps where improved education could promote conservation-oriented behaviors. Based on our interview data, we developed three latent class models of salmon angler typologies based on: 1) anglers' fishing behaviors and preferences, 2) anglers' perceived risks to salmon survival due to post-capture live release, and 3) anglers' level of support for education programs. In the first model, we identified salmon-only anglers (33% of sample), lake-species specialists (46%), and all-around anglers (21%). These classes were differentiated primarily by non-salmon fishing activities (e.g., other target species). In the second model, we found four classes of anglers who differed with regards to key factors they thought affected post-release survival: air exposure (39% of sample); water temperature (24%); hook location (22%); and revival effort (15%). In the third model, we found anglers were either supporters (73%) or non-supporters (27%) of angler education programs. Heterogeneity existed among anglers but we found no correlations in angler classes across models, nor any significant demographic or experiential predictors of class membership. Respondents generally had high awareness and application of catch-and-release best practices, with lake-species specialists rating a higher awareness and usage of recommended catch-and-release technique, and were significantly more likely to cut the line on deeply hooked fish than other groups. Our findings provide resource managers with important insight into the attitudes and behaviors of sockeye salmon anglers in the important lower Fraser River recreational fishery. Our

  13. Di(2-ethylhexyl)phosphoric acid-coconut oil supported liquid membrane for the separation of copper ions from copper plating wastewater.

    PubMed

    Venkateswaran, P; Navaneetha Gopalakrishnan, A; Palanivelu, K

    2007-01-01

    Permeation of Cu(II) from its aqueous solution through a supported liquid membrane (SLM) containing di(2-ethylhexyl)phosphoric acid (D2EHPA) carrier dissolved in coconut oil has been studied. The effects of Cu(II), pH (in feed), H2SO4 (stripping) and D2EHPA (in membrane) concentrations have been investigated. The stability of the D2EHPA-coconut oil has also been evaluated. High Cu(II) concentration in the feed leads to an increase in flux from 4.1 x 10(-9) to 8.9 x 10(-9) mol/(m2 x s) within the Cu(II) concentration range 7.8 x 10(-4)-78.6 x 10(-4) mol/L at pH of 4.0 in the feed and 12.4 x 10-4 mol/L D2EHPA in the membrane phase. Increase in H2SO4 concentration in strip solution leads to an increase in copper ions flux up to 0.25 mol/L H2SO4, providing a maximum flux of 7.4 x 10(-9) mol/(m2 x s). The optimum conditions for Cu(II) transport are, pH of feed 4.0, 0.25 mol/L H2SO4 in strip phase and 12.4 x 10(-4) mol/L D2EHPA (membrane) in 0.5 microm pore size polytetrafluoroethylene (PTFE) membrane. It has been observed that Cu(II) flux across the membrane tends to increase with the concentration of copper ions. Application of the method developed to copper plating bath rinse solutions has been found to be successful in the recovery of Cu(II).

  14. Chitosan/halloysite beads fabricated by ultrasonic-assisted extrusion-dripping and a case study application for copper ion removal.

    PubMed

    Choo, Cheng Keong; Kong, Xin Ying; Goh, Tze Lim; Ngoh, Gek Cheng; Horri, Bahman Amini; Salamatinia, Babak

    2016-03-15

    Development of new materials for different applications especially as bio-composites has received great attention. This study concentrates on development of a biopolymer based on chitosan (CT) and halloysite nanotubes (HNT) and evaluates the copper removal intake as a potential application of this bio-composite. In this study, CT/HNT beads were prepared by ultrasonic-assisted extrusion-dripping method for the first time. Two sources of HNTs (i.e. Dragonite and Matauri Bay) were added into a chitosan solution (2wt.%) at various loading fractions (25, 50, 75wt.%). The effect of ultrasound as a mixing device was also studied by varying the amplitude at constant frequency of 25%, 50% and 75%. Characteristics and physical properties of the prepared CT/HNT beads were also analyzed by SEM, FTIR, TGA and BET the results show that introducing HNT to chitosan increases the adsorption capacity toward copper ions; however HNT loading fraction above 50wt.% resulted in a decrease in adsorption capacity attributed to limited accessibility of the amino groups. The adsorption capacity of the CT/HNT beads prepared from Dragonite source had a larger adsorption capacity of 14.2mg/g as compared to that of Matauri Bay, 10.55mg/g. It was observed that the adsorption capacity of the beads toward copper ions decreased when the loading fraction of HNT is increased at constant ultrasound amplitude. The result of this study helps to understand the links between the characteristics and adsorption abilities of CT/HNT beads.

  15. 5-Fluorouracil acetic acid/beta-cyclodextrin conjugates: drug release behavior in enzymatic and rat cecal media.

    PubMed

    Udo, Koichi; Hokonohara, Kazuhiro; Motoyama, Keiichi; Arima, Hidetoshi; Hirayama, Fumitoshi; Uekama, Kaneto

    2010-03-30

    5-Fluorouracil-1-acetic acid (5-FUA) was prepared and covalently conjugated to beta-cyclodextrin (beta-CyD) through ester or amide linkage, and the drug release behavior of the conjugates in enzymatic solutions and rat cecal contents were investigated. The 5-FUA/beta-CyD ester conjugate was slowly hydrolyzed to 5-FUA in aqueous solutions (half lives (t(1/2))=38 and 17h at pH 6.8 and 7.4, respectively, at 37 degrees C), whereas the amide conjugate was hardly hydrolyzed at these physiological conditions, but hydrolyzed only in strong alkaline solutions (>0.1M NaOH) at 60 degrees C. Both ester and amide conjugates were degraded in solutions of a sugar-degrading enzyme, alpha-amylase, to 5-FUA/maltose and triose conjugates, but the release of 5-FUA was only slight in alpha-amylase solutions. In solutions of an ester-hydrolyzing enzyme, carboxylic esterase, the ester conjugate was hydrolyzed to 5-FUA at the same rate as that in the absence of the enzyme, whereas the amide conjugate was not hydrolyzed by the enzyme. On the other hand, 5-FUA was rapidly released when the ester conjugate was firstly hydrolyzed by alpha-amylase, followed secondly by carboxylic esterase. The results indicated that the ester conjugate was hydrolyzed to 5-FUA in a consecutive manner, i.e. it was firstly hydrolyzed to the small saccharide conjugates, such as the maltose conjugate, by alpha-amylase, and the resulting small saccharide conjugates having less steric hindrance was susceptible to the action of carboxylic esterase, giving 5-FUA. The in vitro release behavior of the ester conjugate was clearly reflected in the hydrolysis in rat cecal contents and in the in vivo release after oral administration to rats.

  16. Dynamics of rapid dopamine release in the nucleus accumbens during goal-directed behaviors for cocaine versus natural rewards.

    PubMed

    Cameron, Courtney M; Wightman, R Mark; Carelli, Regina M

    2014-11-01

    Electrophysiological studies show that distinct subsets of nucleus accumbens (NAc) neurons differentially encode information about goal-directed behaviors for intravenous cocaine versus natural (food/water) rewards. Further, NAc rapid dopamine signaling occurs on a timescale similar to phasic cell firing during cocaine and natural reward-seeking behaviors. However, it is not known whether dopamine signaling is reinforcer specific (i.e., is released during responding for only one type of reinforcer) within discrete NAc locations, similar to neural firing dynamics. Here, fast-scan cyclic voltammetry (FSCV) was used to measure rapid dopamine release during multiple schedules involving sucrose reward and cocaine self-administration (n = 8 rats) and, in a separate group of rats (n = 6), during a sucrose/food multiple schedule. During the sucrose/cocaine multiple schedule, dopamine increased within seconds of operant responding for both reinforcers. Although dopamine release was not reinforcer specific, more subtle differences were observed in peak dopamine concentration [DA] across reinforcer conditions. Specifically, peak [DA] was higher during the first phase of the multiple schedule, regardless of reinforcer type. Further, the time to reach peak [DA] was delayed during cocaine-responding compared to sucrose. During the sucrose/food multiple schedule, increases in dopamine release were also observed relative to operant responding for both natural rewards. However, peak [DA] was higher relative to responding for sucrose than food, regardless of reinforcer order. Overall, the results reveal the dynamics of rapid dopamine signaling in discrete locations in the NAc across reward conditions, and provide novel insight into the functional role of this system in reward-seeking behaviors.

  17. Development of a four-zone carousel process packed with metal ion-imprinted polymer for continuous separation of copper ions from manganese ions, cobalt ions, and the constituent metal ions of the buffer solution used as eluent.

    PubMed

    Jo, Se-Hee; Park, Chanhun; Yi, Sung Chul; Kim, Dukjoon; Mun, Sungyong

    2011-08-19

    A three-zone carousel process, in which Cu(II)-imprinted polymer (Cu-MIP) and a buffer solution were employed as adsorbent and eluent respectively, has been developed previously for continuous separation of Cu²⁺ (product) from Mn²⁺ and Co²⁺ (impurities). Although this process was reported to be successful in the aforementioned separation task, the way of using a buffer solution as eluent made it inevitable that the product stream included the buffer-related metal ions (i.e., the constituent metal ions of the buffer solution) as well as copper ions. For a more perfect recovery of copper ions, it would be necessary to improve the previous carousel process such that it can remove the buffer-related metal ions from copper ions while maintaining the previous function of separating copper ions from the other 2 impure heavy-metal ions. This improvement was made in this study by proposing a four-zone carousel process based on the following strategy: (1) the addition of one more zone for performing the two-step re-equilibration tasks and (2) the use of water as the eluent of the washing step in the separation zone. The operating conditions of such a proposed process were determined on the basis of the data from a series of single-column experiments. Under the determined operating conditions, 3 runs of carousel experiments were carried out. The results of these experiments revealed that the feed-loading time was a key parameter affecting the performance of the proposed process. Consequently, the continuous separation of copper ions from both the impure heavy-metal ions and the buffer-related metal ions could be achieved with a purity of 91.9% and a yield of 92.8% by using the proposed carousel process based on a properly chosen feed-loading time.

  18. Controllable biodegradability, drug release behavior and hemocompatibility of PTX-eluting magnesium stents.

    PubMed

    Lu, Ping; Fan, Hainan; Liu, Yin; Cao, Lu; Wu, Xiangfeng; Xu, Xinhua

    2011-03-01

    Cardiovascular magnesium-based stents have been already applied in patients. However, their high corrosion rate hinders their clinical application. In this study, we adopt a new approach in the design of a Mg-based stent to improve the biodegradation rate and the drug release rate. By fabricating a micro-arc oxidation/poly-l-lactic acid (MAO/PLLA) composite coating on the magnesium alloy AZ81 substrate, the corrosion resistance decreased and the biodegradation rate became controllable. The drug release coating was composed of one Poly(dl-lactide-co-glycolide)/paclitaxel (PLGA/PTX) layer and one pure PLGA blank layer without paclitaxel, and this coating also functions to provide controlled biodegradation rate of the stent. The drug release rate was controlled by controlling the ratio of the LA:GA of the PLGA without PTX. The scanning electron microscopy (SEM) images were used to demonstrate the morphology of the samples before and after this modification. The blood compatibility of the samples was demonstrated by the platelet adhesion test. The drug release was determined by ultraviolet-visible (UV-visible) spectrophotometer. The result showed that the PLLA effectively sealed the micro-cracks and micro-holes on the surface of the MAO coating to give controllable biodegradation of the AZ81. The drug release rate of PTX exhibited a nearly linear sustained-release profile with no significant burst releases that would come from the uncontrolled oxidation/corrosion of AZ81. The samples modified had better hemocompatibility than 316L stainless steel.

  19. Preparation of poly(N-isopropylacrylamide) emulsion gels and their drug release behaviors.

    PubMed

    Tokuyama, Hideaki; Kato, Yuya

    2008-11-15

    Stimuli-sensitive drug delivery systems (DDSs) have attracted considerable attention in medical and pharmaceutical fields; thermosensitive DDS dealing with poly(N-isopropylacrylamide) (poly(NIPA)) have been widely studied. Novel NIPA emulsion gels, i.e., NIPA hydrogels containing distributed oil (oleyl alcohol) microdroplets, were synthesized by means of an emulsion-gelation method in which the polymerization of hydrogels in an aqueous phase in an oil-in-water (O/W) emulsion and the loading of a lipophilic drug (indomethacin) dissolved in an oil phase were accomplished simultaneously. The pulsatile (on-off) drug release from the NIPA emulsion gel loading indomethacin to a phosphate buffered saline (PBS) solution was successfully controlled by a temperature swing between 25 degrees C (release off) and 40 degrees C (release on). The mechanism of the pulsatile drug release was discussed in relation to the diffusion rate, distribution ratio, solvent exchange of NIPA hydrogels, and drug release from an NIPA organogel. The mechanism was as follows: the solvent exchange occurred within the NIPA emulsion gel (the NIPA gel-network absorbed oleyl alcohol with indomethacin) at temperatures above the LCST, and the diffusion rate of indomethacin through the solvent-exchanged gel was higher at 40 degrees C than at 25 degrees C.

  20. Effect of drying and loading methods on the release behavior of ciprofloxacin from starch nanoparticles.

    PubMed

    Shi, Aimin; Li, Dong; Liu, Hongzhi; Adhikari, Benu; Wang, Qiang

    2016-06-01

    Drug loading into and release from starch nanoparticles (StNPs), one kind of novel biological macromolecule, were investigated. Two drying methods (spray and vacuum freeze drying) and drug loading methods (coating and adsorption) were used for evaluation. 40% (w/w) of ciprofloxacin was loaded using coating method while only 7% for adsorption method. Glass transition temperature (Tg) and melting point temperature (Tmp) of ciprofloxacin loaded starch nanoparticles varied from 40°C to 55°C and 125°C to 175°C. Particles using adsorption method had lower loading rate of ciprofloxacin, higher Tg, Tmp and release rate compared to using coating method. Tg and Tmp were not affected by these two drying methods. Release rate of ciprofloxacin was higher from freeze dried particles than from spray dried particles using coating method. For adsorption method, drying methods had not effect on the release rate. A double decay exponential model was able to fit the release data suitably well with coefficient of determination (R(2))>0.97.

  1. Behavioral effects of peripheral corticotropin-releasing factor during maternal separation may be mediated by proinflammatory activity

    PubMed Central

    Hennessy, Michael B.; Fitch, Christopher; Jacobs, Sarah; Deak, Terrence; Schiml, Patricia A.

    2013-01-01

    Summary When guinea pig pups are separated from their mothers in a novel environment, an initial period of active behavior (vocalizing, locomotor activity) wanes after an hour or so and is replaced by a second, passive stage characterized by a crouched stance, closed eyes, and extensive piloerection. If pups are given a peripheral injection of 7–14 μg of corticotropin-releasing factor (CRF) prior to testing, the passive behaviors occur immediately upon separation. We found that intracerebroventricular infusion of 1–10 μg of CRF did not increase passive behavior relative to vehicle infusion, but that peripheral injection of the anti-inflammatory cytokine, Interleukin-10, attenuated the passive behavior induced by peripheral CRF injection. These results together with previous findings suggest that peripheral CRF administration affects behavior of separated guinea pig pups through a mechanism that involves peripheral proinflammatory activity. The possible role of endogenous peripheral CRF in the behavioral response of untreated pups during maternal separation is considered. PMID:21255937

  2. Evaluating the effects of crystallinity in new biocompatible polyester nanocarriers on drug release behavior.

    PubMed

    Karavelidis, Vassilios; Karavas, Evangelos; Giliopoulos, Dimitrios; Papadimitriou, Sofia; Bikiaris, Dimitrios

    2011-01-01

    Four new polyesters based on 1,3-propanediol and different aliphatic dicarboxylic acids were used to prepare ropinirole HCl-loaded nanoparticles. The novelty of this study lies in the use of polyesters with similar melting points but different degrees of crystallinity, varying from 29.8% to 67.5%, as drug nanocarriers. Based on their toxicity to human umbilical vein endothelial cells, these aliphatic polyesters were found to have cytotoxicity similar to that of polylactic acid and so may be considered as prominent drug nanocarriers. Drug encapsulation in polyesters was performed via an emulsification/solvent evaporation method. The mean particle size of drug-loaded nanoparticles was 164-228 nm, and the drug loading content was 16%-23%. Wide angle X-ray diffraction patterns showed that ropinirole HCl existed in an amorphous state within the nanoparticle polymer matrices. Drug release diagrams revealed a burst effect for ropinirole HCl in the first 6 hours, probably due to release of drug located on the nanoparticle surface, followed by slower release. The degree of crystallinity of the host polymer matrix seemed to be an important parameter, because higher drug release rates were observed in polyesters with a low degree of crystallinity.

  3. Evaluating the effects of crystallinity in new biocompatible polyester nanocarriers on drug release behavior

    PubMed Central

    Karavelidis, Vassilios; Karavas, Evangelos; Giliopoulos, Dimitrios; Papadimitriou, Sofia; Bikiaris, Dimitrios

    2011-01-01

    Four new polyesters based on 1,3-propanediol and different aliphatic dicarboxylic acids were used to prepare ropinirole HCl-loaded nanoparticles. The novelty of this study lies in the use of polyesters with similar melting points but different degrees of crystallinity, varying from 29.8% to 67.5%, as drug nanocarriers. Based on their toxicity to human umbilical vein endothelial cells, these aliphatic polyesters were found to have cytotoxicity similar to that of polylactic acid and so may be considered as prominent drug nanocarriers. Drug encapsulation in polyesters was performed via an emulsification/solvent evaporation method. The mean particle size of drug-loaded nanoparticles was 164–228 nm, and the drug loading content was 16%–23%. Wide angle X-ray diffraction patterns showed that ropinirole HCl existed in an amorphous state within the nanoparticle polymer matrices. Drug release diagrams revealed a burst effect for ropinirole HCl in the first 6 hours, probably due to release of drug located on the nanoparticle surface, followed by slower release. The degree of crystallinity of the host polymer matrix seemed to be an important parameter, because higher drug release rates were observed in polyesters with a low degree of crystallinity. PMID:22162659

  4. Effect of mechanical and electrical behavior of gelatin hydrogels on drug release and cell proliferation.

    PubMed

    Biswal, Dibyajyoti; Anupriya, B; Uvanesh, K; Anis, Arfat; Banerjee, Indranil; Pal, Kunal

    2016-01-01

    The present study was aimed to explore the effect of the mechanical and the electrical properties of the gelatin hydrogels on the mammalian cell proliferation and drug release properties. FTIR analysis of the hydrogels suggested that gelatin retained its secondary protein structure. A decrease in the diffusion constant of the water molecules was observed with the increase in the gelatin concentration in the hydrogels. The mechanical and the electrical stabilities of the hydrogels were enhanced with the increase in the gelatin content. Stress relaxation and creep studies were modeled using Weichert and Burger׳s models, respectively. The relaxation time (stress relaxation study) did not follow a concentration-dependent relationship and was found to affect the MG-63 cell (human osteoblast) proliferation. The impedance profile of the hydrogels was modeled using a (RQ)Q model. Release of ciprofloxacin from the hydrogels was inversely dependent on the rate of swelling. The release of the drug was not only dependent on the Fickian diffusion but also on the relaxation process of the gelatin chains. The inhomogeneous constant of the constant phase element representing the hydrogel-electrode interface indicated improved cell proliferation rate with a decrease in the inhomogeneous constant. In gist, the rate of cell proliferation could be related to the relaxation time (stress relaxation) and the inhomogeneous constant of the sample-electrode constant phase element (electrical study) properties, whereas, the drug release properties can be related to the bulk resistance of the formulations.

  5. Release behavior of trans,trans-farnesol entrapped in amorphous silica capsules

    PubMed Central

    Sousa, Filipa L.; Horta, Sara; Santos, Magda; Rocha, Sĺlvia M.; Trindade, Tito

    2012-01-01

    Farnesol, a compound widely found in several agro-food by-products, is an important bioactive agent that can be exploited in cosmetics and pharmaceutics but the direct bioapplication of this compound is limited by its volatility. Here the entrapment of farnesol in silica capsules was investigated to control the release of this bioactive compound in the vapor phase and in ethanol solutions. The preparation of silica capsules with oil cores was obtained by employing a sol–gel method using O/W/O multiple emulsions. Two distinct chemical vehicles for farnesol have been investigated, retinol and oleic acid, that afterwards have been emulsified as internal oil phases. The volatile release of farnesol from the as-prepared SiO2 capsules was investigated by headspace solid phase microextraction (HS-SPME) followed by gas chromatographic analysis (GC), and the release to ethanol was carried out by direct injection of the ethanolic fraction into the GC system. It is demonstrated that these capsules are efficient for the long controlled release of farnesol and that the respective profiles depend on the chemical parameters employed in the synthesis of the capsules. PMID:25755994

  6. Diazepam-induced release of behavior in an extinction procedure: its reversal by Ro 15-1788.

    PubMed

    Thiébot, M H; Childs, M; Soubrié, P; Simon, P

    1983-03-18

    The effects of the benzodiazepine receptor antagonist Ro 15-1788, an imidazobenzodiazepine derivative, were studied with respect to three pharmacological activities exerted by diazepam in rats. Two of these, release of shock-induced suppression of drinking and attenuation of non-reward-induced cessation of responding for food, reflect the anxiolytic property of benzodiazepines. The amnesic-like effect of diazepam was also investigated. Ro 15-1788 (in doses ranging from 4 to 16 mg/kg p.o.) completely reversed diazepam (2 mg/kg)-induced release of behavior in both punishment and non-reward procedures. In contrast, Ro 15-1788 reduced but did not completely abolish diazepam-induced amnesia. These data suggest that the anticonflict and anti-frustration effects of benzodiazepines probably involve similar receptor types which nevertheless differ from those chiefly implicated in the amnesic-like activity of benzodiazepines.

  7. Behaviors of controlled drug release of magnetic-gelatin hydrogel coated stainless steel for drug-eluting-stents application

    NASA Astrophysics Data System (ADS)

    Huang, Li-Ying; Yang, Ming-Chien

    2007-03-01

    The behavior of drug release controlled by magnetic fields (MF) for stainless steel coated with magnetic-gelatin (MAG-GE) hydrogel was investigated in this paper. X-ray photoelectron spectroscope (XPS) and vibrating sample magnetometer were used to evaluate the characterizations of MAG-GE hydrogel and the interaction with the surface of SUS316L. A model drug (sirolimus) was loaded to the MAG-GE hydrogel. When applying MF to the MAG-GE hydrogel, the sirolimus release rate of the magnetic hydrogel decreased by {1}/{3}, comparing to that without the field. This suggests a "close" configuration of the MAG-GE hydrogel due to the aggregation of magnetic nanoparticles which reduced the pore size of MAG-GE hydrogel.

  8. Quinolinic acid released from polymeric brain implants causes behavioral and neuroanatomical alterations in a rodent model of Huntington's disease.

    PubMed

    Haik, K L; Shear, D A; Schroeder, U; Sabel, B A; Dunbar, G L

    2000-06-01

    Quinolinic acid (QA) is an N-methyl-d-aspartate agonist that has been shown to produce neurotoxic effects that mimic certain neurodegenerative diseases when administered to laboratory animals. Intrastriatal injections of QA in rats have been used extensively to produce some of the neuropathological and behavioral deficits that are analogous to Huntington's disease (HD). However, acute intrastriatal injections of QA produce symptoms that are not analogous to the progressive nature of HD. Thus far, models using chronic administration of QA that produce HD-like behavioral and neuroanatomical changes have necessitated the use of a relatively bulky and fragile microdialytic pump apparatus. The present study tested an alternative way of chronically administering QA. Specifically, this study tested whether gradual release of QA from ethylene vinylacetate (EVA) polymers could produce symptoms analogous to HD. Rats received either no implants or bilateral intrastriatal implants of polymers with or without QA. Subsequent tests for spontaneous motor activity (SMA), grip strength, balance, and learning ability in a radial-arm-water-maze task revealed QA-induced impairments in balance and learning ability, but did not affect grip strength or SMA. Histological analysis revealed QA-induced enlargement of lateral ventricles, striatal atrophy, and striatal neuronal loss, with relative sparing of NADPH-diaphorase-positive neurons. These results suggest that QA released from polymers can produce behavioral and neuropathological profiles analogous to early stages of HD and that EVA polymers offer a useful means of chronically delivering QA in rodent models of neurodegeneration.

  9. Chemical and behavioral analyses of volatile sex pheromone components released by callingHeliothis virescens (F.) females (Lepidoptera: Noctuidae).

    PubMed

    Teal, P E; Tumlinson, J H; Heath, R R

    1986-01-01

    Gas chromatographic and mass spectral analyses were conducted on pheromone gland extracts, volatiles collected from excised pheromone glands, and volatiles collected from calling females. In addition to tetradecanal, (Z)-9-tetradecenal, hexadecanal, (Z)-7-hexadecenal, (Z)-9-hexadecenal, and (Z)-11-hexadecenal, four other compounds, tetradecanol, (Z)-9-tetradecenol, hexadecanol, and (Z)-11-hexadecenol, were also identified from gland extracts. Only the six aldehyde components were found in gland and female volatile collections. The mean percentage of components identified from volatiles collected from calling females was 13.0% tetradecanal, 18.1% (Z)-9-tetradecenal, 7.3% hexadecanal, 0.6% (Z)-7-hexadecenal, 1.0% (Z)-9-hexadecenal, and 60.0% (Z)-11-hexadecenal. Bioassays using rubber septa formulated to release the female volatile blend indicated that all six aldehyde components play major roles in close-range male reproductive behavior. Deletion of (Z)-9-hexadecenal from the six-component blend reduced the number of copulation attempts while (Z)-7-hexadecenal exerted subtle effects on all close range behaviors. Tetradecanal affected the number of times males reorient from close range. Deletion of hexadecanal from the six-component blend resulted in a significant reduction in the number of times males landed. Comparison of the six-component synthetic blend (released at somewhat less than 1 female equivalent per hour) with calling females indicated that the six-component blend was indistinguishable from the females in inducing all of the behaviors monitored.

  10. Electroantennographic and behavioral responses of adults of raspberry weevil Aegorhinus superciliosus (Coleoptera: Curculionidae) to odors released from conspecific females.

    PubMed

    Mutis, Ana; Parra, Leonardo; Manosalva, Loreto; Palma, Rubén; Candia, Oscar; Lizama, Marcelo; Pardo, Fernando; Perich, Fernando; Quiroz, Andrés

    2010-08-01

    The raspberry weevil, Aegorhinus superciliosus (Guérin) (Coleoptera: Curculionidae), is the most important pest in blueberry and raspberry fields in the south of Chile. In this study, we investigated the electroantennographic and behavioral responses of A. superciliosus to semiochemicals released from conspecific individual adults, with particular attention to male attraction to females. Odors released from females significantly attracted males in a Y-tube olfactometer. Gas chromatographic and mass spectral analysis of female volatile extracts revealed the presence of limonene and α-pinene. Electroantennogram recordings from both sexes indicated that males of A. superciliosus possess olfactory sensitivity for the R isomer of limonene and α-pinene, whereas females only perceived R-limonene. Behavioral assays using synthetic compounds showed that only R-limonene elicited an attraction response from male weevils. Field experiments confirmed the laboratory results, showing that R-limonene was attractive to weevils. This is the first report of intraspecific chemical communication in this weevil. We discuss the origin of these compounds, their possible role in the sexual behavior of this species, and their potential use in a pest control strategy.

  11. Phosphorus release behaviors of poultry litter biochar as a soil amendment.

    PubMed

    Wang, Yue; Lin, Yingxin; Chiu, Pei C; Imhoff, Paul T; Guo, Mingxin

    2015-04-15

    Phosphorus (P) may be immobilized and consequently the runoff loss risks be reduced if poultry litter (PL) is converted into biochar prior to land application. Laboratory studies were conducted to examine the water extractability of P in PL biochar and its release kinetics in amended soils. Raw PL and its biochar produced through 400°C pyrolysis were extracted with deionized water under various programs and measured for water extractable P species and contents. The materials were further incubated with a sandy loam at 20 g kg(-1) soil and intermittently leached with water for 30 days. The P release kinetics were determined from the P recovery patterns in the water phase. Pyrolysis elevated the total P content from 13.7 g kg(-1) in raw PL to 27.1 g kg(-1) in PL biochar while reduced the water-soluble P level from 2.95 g kg(-1) in the former to 0.17 g kg(-1) in the latter. The thermal treatment transformed labile P in raw PL to putatively Mg/Ca phosphate minerals in biochar that were water-unextractable yet proton-releasable. Orthophosphate was the predominant form of water-soluble P in PL biochar, with condensed phosphate (e.g., pyrophosphate) as a minor form and organic phosphate in null. Release of P from PL biochar in both water and neutral soils was at a slower and steadier rate over a longer time period than from raw PL. Nevertheless, release of P from biochar was acid-driven and could be greatly promoted by the media acidity. Land application of PL biochar at soil pH-incorporated rates and frequency will potentially reduce P losses to runoffs and minimize the adverse impact of waste application on aquatic environments.

  12. Interactions between Surfactants in Solution and Electrospun Protein Fibers: Effects on Release Behavior and Fiber Properties.

    PubMed

    Stephansen, Karen; García-Díaz, María; Jessen, Flemming; Chronakis, Ioannis S; Nielsen, Hanne M

    2016-03-07

    Intermolecular interaction phenomena occurring between endogenous compounds, such as proteins and bile salts, and electrospun compounds are so far unreported, despite the exposure of fibers to such biorelevant compounds when applied for biomedical purposes, e.g., tissue engineering, wound healing, and drug delivery. In the present study, we present a systematic investigation of how surfactants and proteins, as physiologically relevant components, interact with insulin-loaded fish sarcoplasmic protein (FSP) electrospun fibers (FSP-Ins fibers) in solution and thereby affect fiber properties such as accessible surface hydrophilicity, physical stability, and release characteristics of an encapsulated drug. Interactions between insulin-loaded protein fibers and five anionic surfactants (sodium taurocholate, sodium taurodeoxycholate, sodium glycocholate, sodium glycodeoxycholate, and sodium dodecyl sulfate), a cationic surfactant (benzalkonium chloride), and a neutral surfactant (Triton X-100) were studied. The anionic surfactants increased the insulin release in a concentration-dependent manner, whereas the neutral surfactant had no significant effect on the release. Interestingly, only minute amounts of insulin were released from the fibers when benzalkonium chloride was present. The FSP-Ins fibers appeared dense after incubation with this cationic surfactant, whereas high fiber porosity was observed after incubation with anionic or neutral surfactants. Contact angle measurements and staining with the hydrophobic dye 8-anilino-1-naphthalenesulfonic acid indicated that the FSP-Ins fibers were hydrophobic, and showed that the fiber surface properties were affected differently by the surfactants. Bovine serum albumin also affected insulin release in vitro, indicating that also proteins may affect the fiber performance in an in vivo setting.

  13. Formation and release behavior of iron corrosion products under the influence of bacterial communities in a simulated water distribution system.

    PubMed

    Sun, Huifang; Shi, Baoyou; Lytle, Darren A; Bai, Yaohui; Wang, Dongsheng

    2014-03-01

    To understand the formation and release behavior of iron corrosion products in a drinking water distribution system, annular reactors (ARs) were used to investigate the development processes of corrosion products and biofilm community as well as the concomitant iron release behavior. Results showed that the formation and transformation of corrosion products and bacterial community are closely related to each other. The presence of sulfate-reducing bacteria (SRB, e.g. Desulfovibrio and Desulfotomaculum), sulfur-oxidizing bacteria (SOB, e.g. Sulfuricella), and iron-oxidizing bacteria (IOB, e.g. Acidovorax, Gallionella, Leptothrix, and Sphaerotilus) in biofilms could speed up iron corrosion; however, iron-reducing bacteria (IRB, e.g. Bacillus, Clostridium, and Pseudomonas) could inhibit iron corrosion and iron release. Corrosion scales on iron coupons could develop into a two-layered structure (top layer and inner layer) with time. The relatively stable constituents such as goethite (α-FeOOH) and magnetite (Fe3O4) mainly existed in the top layers, while green rust (Fe6(OH)12CO3) mainly existed in the inner layers. The IOB (especially Acidovorax) contributed to the formation of α-FeOOH, while IRB and the anaerobic conditions could facilitate the formation of Fe3O4. Compared with the AR test without biofilms, the iron corrosion rate with biofilms was relatively higher (p < 0.05) during the whole experimental period, but the iron release with biofilms was obviously lower both at the initial stage and after 3 months. Biofilm and corrosion scale samples formed under different water supply conditions in an actual drinking water distribution system verified the relationships between the bacterial community and corrosion products.

  14. Time Since Release from Incarceration and HIV Risk Behaviors Among Women: The Potential Protective Role of Committed Partners During Re-entry.

    PubMed

    Hearn, Lauren E; Whitehead, Nicole Ennis; Khan, Maria R; Latimer, William W

    2015-06-01

    After release from incarceration, former female inmates face considerable stressors, which may influence drug use and other risk behaviors that increase risk for HIV infection. Involvement in a committed partnership may protect women against re-entry stressors that may lead to risky behaviors. This study measured the association between time since release from incarceration (1-6 months ago, and >6 months ago versus never incarcerated) and HIV risk behaviors and evaluated whether these associations differed by involvement in a committed partnership. Women released within the past 6 months were significantly more likely to have smoked crack cocaine, used injection drugs and engaged in transactional sex in the past month compared to never-incarcerated women and women released more distally. Stratified analyses indicated that incarceration within the past 6 months was associated with crack cocaine smoking, injection drug use and transactional sex among women without a committed partner yet unassociated with these risk behaviors among those with a committed partner.

  15. Alpha-Melanocyte-Stimulating Hormone Attenuates Behavioral Effects of Corticotropin-Releasing Factor in Isolated Guinea Pig Pups

    PubMed Central

    Miller, Emily; Deak, Terrence; Hennessy, Michael B.

    2016-01-01

    During a 3-hr period of social isolation in a novel environment, guinea pig pups exhibit an initial active phase of behavioral responsiveness, characterized primarily by vocalizing, which is then followed by a stage of passive responsiveness in which pups display a distinctive crouch, eye-closing, and extensive piloerection. Prior treatment of pups with alpha-melanocyte-stimulating hormone (α-MSH) reduces each of the passive behaviors. The onset of passive responding during separation can be accelerated with peripheral injection of corticotropin-releasing factor (CRF). To examine whether CRF produces its effects through a mechanism similar to that of prolonged separation, we examined the effect of administering α-MSH to pups injected with CRF. As expected, CRF markedly enhanced passive responding during a 60-min period of separation. α-MSH delivered by either intracerebroventricular infusion or intraperitoneal injection significantly reduced each of the passive behavioral responses without significantly affecting active behavior. These findings, together with previous results indicating that it is the anti-inflammatory property of α-MSH that is responsible for its behavioral effects during prolonged separation, suggest that peripheral CRF speeds the induction of passive responding through a mechanism involving enhanced proinflammatory activity. PMID:19492314

  16. Measuring the dynamic compression and release behavior of rocks and grouts associated with HYDROPLUS

    SciTech Connect

    Furnish, M.D.

    1993-10-01

    Gas-gun impact tests were performed on twelve rocks and rock simulants pertinent to the HYDROPLUS nuclear yield measurement program: A variety of tuffs, rhyolites, carbonates, grouts, an epoxy-alumina mixture and quartzite permafrost samples recovered in an apparently preserved frozen state from northern Canada. The present report presents results for all of these materials except for the carbonates. Two classes of impact techniques were employed for measuring equation-of-state properties for these materials. Both use velocity interferometry diagnostics. One, employing a sample-in-projectile geometry, provides high-precision Hugoniot data and continuous release trajectories for dry or water-saturated materials. The majority of the experiments were performed with this geometry. The other, employing a sample-in-target geometry, provides loading path and Hugoniot data as well as limited release data. Uncertainties in the results have been estimated by analyzing the effects of errors in observables and ancillary material properties.

  17. Preparation and drug release behavior of temperature-responsive mesoporous carbons

    SciTech Connect

    Wang Xiufang; Liu Ping; Tian Yong

    2011-06-15

    A temperature-responsive composite based on poly (N-isopropylacrylamide) (PNIPAAm) and ordered mesoporous carbons (OMCs) has been successfully prepared by a simple wetness impregnation technique. The structures and properties of the composite were characterized by infrared spectroscopy (IR), X-ray diffraction (XRD), transmission electron microscopy (TEM), N{sub 2} sorption, thermogravimetric analysis (TG) and differential scanning calorimetry (DSC). The results showed that the inclusion of PNIPAAm had not greatly changed the basic ordered pore structure of the OMCs. Ibuprofen (IBU) was selected as model drug, and in vitro test of IBU release exhibited a temperature-responsive controlled release delivery. - Graphical abstract: The bands located at 1650 and 1549 cm{sup -1} could be assigned to C=O stretching and N-H bending vibrations for polymer PNIPAAm (a). The bands at 1388 and 1369 cm{sup -1} were due to isopropyl group, and the band at 1459 cm{sup -1} was related to the bending vibration of C-H (a). For the PNIPAAm/OMCs composite, the characteristic bands of polymer were still observed besides those for carbon materials and the bands at around 1585 cm{sup -1} and a broad band at about 1100 cm{sup -1} were characteristics for the carbon materials(c). In addition, little shifts of C=O and N-H bands compared to the pure PNIPAAm were also observed (b), indicating a weak interaction between the polymer and carbon material. These results could be a proof that the PNIPAAm has been incorporated into the carbon material. Highlights: > A temperature-responsive PNIPAAm/OMCs composite was successfully synthesized by a simple wetness impregnation technique for the first time. > The inclusion of PNIPAAm had not greatly changed the basic ordered pore structure of the OMCs. > In vitro test of IBU release exhibited a temperature-responsive controlled release delivery.

  18. Influence of hydrophobe on the release behavior of vinyl acetate miniemulsion polymerization.

    PubMed

    Park, Soo-Jin; Kim, Ki-Seok

    2005-11-25

    Poly(vinyl acetate) (PVAc) nanoparticles containing antibiotic have been prepared by miniemulsion polymerization. To compare the effect of hydrophobe types, hexadecane and poly(vinyl acetate) were used as hydrophobe. The particle characteristics as the manufacturing condition were examined by particle size analyzer. As a result, the diameter of PVAc latexes was adjusted between 80 and 260 nm by homogenization conditions and amounts of surfactant. Also, the miniemulsion by using hexadecane showed the more long shelf stability and led to the more small particle size after polymerization, as compared with the case of using poly(vinyl acetate). This indicated that the use of poly(vinyl acetate) as a hydrophobe could not make the stable emulsion, but it could avoid volatile organic chemical problems in the final product. From the release profile of drug through UV spectra, the drug release was very slow and it could be seen that the release of drug encapsulated with PVAc was occurred with the polymer degradation.

  19. A novel drug carrier based on functional modified nanofiber cellulose and the control release behavior

    NASA Astrophysics Data System (ADS)

    Shi, Xiangning; Zheng, Yudong; Zhang, Wei; Zhang, Zeyu; Peng, Yunling

    2013-08-01

    This study developed a novel drug carrier based on functional modified bacterial cellulose(BC) which was conjugated with Ibuprofen(IBU) by esterification. BC-Ibuprofen as the macro- molecular prodrugs and drug carrier used to improve the short half-life of the drug, and was able to control release through the hydrolysis of ester bond between the hydroxyl groups of BC with Ibuprofen under different condition. Fourier transform infrared analysis revealed that Ibuprofen had been successfully grafted onto the bacterial cellulose (BC). Thermal and morphological characterization indicated the formation of the BC-Ibuprofen system incompletely reacted maintained the bulk structure of the pristine material such as crystallinity, 3-dimentional network and so on. The drug release behaviours were affected by the ester bond hydrolysis as well as the microstructure characteristics of the modified nanofiber. The release of BC-IBU showed an apparent pH-dependent, fast in alkaline and acid solution but slow relatively in neutral. Such pH-responsiveness, in addition to its morphological characteristics, in this paper suggested a great potential of BC-IBU as a more effective, safe, and stable prodrug candidate.

  20. Behavior and movement of formerly landlocked juvenile coho salmon after release into the free-flowing Cowlitz River, Washington

    USGS Publications Warehouse

    Kock, Tobias J.; Henning, Julie A.; Liedtke, Theresa L.; Royer, Ida M.; Ekstrom, Brian K.; Rondorf, Dennis W.

    2011-01-01

    Formerly landlocked Coho Salmon (Oncorhynchus kisutch) juveniles (age 2) were monitored following release into the free-flowing Cowlitz River to determine if they remained in the river or resumed seaward migration. Juvenile Coho Salmon were tagged with a radio transmitter (30 fish) or Floy tag (1050 fish) and their behavior was monitored in the lower Cowlitz River. We found that 97% of the radio-tagged fish remained in the Cowlitz River beyond the juvenile outmigration period, and the number of fish dispersing downstream decreased with increasing distance from the release site. None of the tagged fish returned as spawning adults in the 2 y following release. We suspect that fish in our study failed to migrate because they exceeded a threshold in size, age, or physiological status. Tagged fish in our study primarily remained in the Cowlitz River, thus it is possible that these fish presented challenges to juvenile salmon migrating through the system either directly by predation or indirectly by competition for food or habitat. Given these findings, returning formerly landlocked Coho Salmon juveniles to the free-flowing river apparently provided no benefit to the anadromous population. These findings have management implications in locations where landlocked salmon have the potential to interact with anadromous species of concern.

  1. Tissue plasminogen activator promotes the effects of corticotropin-releasing factor on the amygdala and anxiety-like behavior.

    PubMed

    Matys, Tomasz; Pawlak, Robert; Matys, Elzbieta; Pavlides, Constantine; McEwen, Bruce S; Strickland, Sidney

    2004-11-16

    Stress-induced plasticity in the brain requires a precisely orchestrated sequence of cellular events involving novel as well as well known mediators. We have previously demonstrated that tissue plasminogen activator (tPA) in the amygdala promotes stress-induced synaptic plasticity and anxiety-like behavior. Here, we show that tPA activity in the amygdala is up-regulated by a major stress neuromodulator, corticotropin-releasing factor (CRF), acting on CRF type-1 receptors. Compared with WT, tPA-deficient mice responded to CRF treatment with attenuated expression of c-fos (an indicator of neuronal activation) in the central and medial amygdala but had normal c-fos responses in paraventricular nuclei. They exhibited reduced anxiety-like behavior to CRF but had a sustained corticosterone response after CRF administration. This effect of tPA deficiency was not mediated by plasminogen, because plasminogen-deficient mice demonstrated normal behavioral and hormonal changes to CRF. These studies establish tPA as an important mediator of cellular, behavioral, and hormonal responses to CRF.

  2. Cue-Evoked Dopamine Release Rapidly Modulates D2 Neurons in the Nucleus Accumbens During Motivated Behavior

    PubMed Central

    Owesson-White, Catarina; Belle, Anna M.; Herr, Natalie R.; Peele, Jessica L.; Gowrishankar, Preethi; Carelli, Regina M.

    2016-01-01

    Dopaminergic neurons that project from the ventral tegmental area (VTA) to the nucleus accumbens (NAc) fire in response to unpredicted rewards or to cues that predict reward delivery. Although it is well established that reward-related events elicit dopamine release in the NAc, the role of rapid dopamine signaling in modulating NAc neurons that respond to these events remains unclear. Here, we examined dopamine's actions in the NAc in the rat brain during an intracranial self-stimulation task in which a cue predicted lever availability for electrical stimulation of the VTA. To distinguish actions of dopamine at select receptors on NAc neurons during the task, we used a multimodal sensor that probes three aspects of neuronal communication simultaneously: neurotransmitter release, cell firing, and identification of dopamine receptor type. Consistent with prior studies, we first show dopamine release events in the NAc both at cue presentation and after lever press (LP). Distinct populations of NAc neurons encode these behavioral events at these same locations selectively. Using our multimodal sensor, we found that dopamine-mediated responses after the cue involve exclusively a subset of D2-like receptors (D2Rs), whereas dopamine-mediated responses proximal to the LP are mediated by both D1-like receptors (D1R) and D2Rs. These results demonstrate for the first time that dopamine-mediated responses after cues that predict reward availability are specifically linked to its actions at a subset of neurons in the NAc containing D2Rs. SIGNIFICANCE STATEMENT Successful reward procurement typically involves the completion of a goal-directed behavior in response to appropriate environmental cues. Although numerous studies link the mesolimbic dopamine system with these processes, how dopamine's effects are mediated on the receptor level within a key neural substrate, the nucleus accumbens, remains elusive. Here, we used a unique multimodal sensor that reveals three aspects of

  3. Effect of alginate and chitosan on viability and release behavior of Bifidobacterium pseudocatenulatum G4 in simulated gastrointestinal fluid.

    PubMed

    Kamalian, Nikoo; Mirhosseini, Hamed; Mustafa, Shuhaimi; Manap, Mohd Yazid Abd

    2014-10-13

    The main aim of this study was to investigate the effect of different coating materials (i.e. Na-alginate and chitosan) on the viability and release behavior of Bifidobacterium pseudocatenulatum G4 in the simulated gastric fluid (SGF) and simulated intestinal fluid (SIF). This study reports the viability of encapsulated B. pseudocatenulatum G4 coated using different alginate (2-4 g/100mL) and chitosan (0.2-0.8 g/100mL) concentrations. The results indicated that the highest concentration of alginate (4.4142 g/100mL) along with 0.5578 g/100mL chitosan resulted in the highest viability of B. pseudocatenulatum G4. The release behavior of the encapsulated probiotics in SGF (pH 1.5) in 2h followed by 4h in SIF (pH 7.4) was also assessed. The resistance rate of alginate-chitosan capsule in SGF was higher than SIF. The alginate-chitosan encapsulated cells had also more resistance than alginate capsules. The current study revealed that alginate encapsulated B. Pseudocatenulatum G4 exhibited longer survival than its free cells (control).

  4. Physical behavior of the SEEDS iron-fertilized patch by sulphur hexafluoride tracer release

    NASA Astrophysics Data System (ADS)

    Tsumune, Daisuke; Nishioka, Jun; Shimamoto, Akifumi; Takeda, Shigenobu; Tsuda, Atsushi

    2005-02-01

    The first iron (Fe) - fertilization experiment in the western North Pacific was carried out using SF 6 to trace the Fe-fertilized water mass. A solution in 10,800 liters of seawater of 350 kg of Fe and 0.48 M of SF 6 tracer was released into the mixed layer over a 8 × 10 km area. On the first underway transects through the patch after the Fe release, we observed a significant increase of dissolved Fe (ave. 2.89 nM). The fertilized patch was traced for 14 days by on-board SF 6 analysis. A Lagrangian frame of reference was maintained by the use of a drogued GPS buoy released at the center of the patch. The patch moved westward at a rate of 6.8 km d -1. Mixed layer depth increased from 8.5 to 15 m during the experiment. Horizontal diffusivity was determined by the change of SF 6 concentration in the patch. The horizontal diffusivity increased during the experiment. We evaluate here the fate of Fe in a Fe-fertilized patch using the dilution rate determined from sulphur hexafluoride (SF 6) concentration. Dissolved Fe concentrations subsequently decreased rapidly to ∼0.15 nM on Day 13. However, the dissolved Fe half-life of ∼43 h was relatively longer than in previous Fe-enrichment studies, and we observed a larger increase of the centric diatom standing stock and corresponding drawdown of macro-nutrients and carbon dioxide than in the previous studies. The most important reason for the larger response was the phytoplankton species in the western North Pacific. In addition, the smaller diffusivity and shallower mixed layer were effective to sustain the higher dissolved Fe concentration compared to previous experiments. This might be one reason for the larger response of diatoms in SEEDS.

  5. Thermosensitive ZrP-PNIPAM Pickering Emulsifier and the Controlled-Release Behavior.

    PubMed

    Wang, Xuezhen; Zeng, Minxiang; Yu, Yi-Hsien; Wang, Huiliang; Mannan, M Sam; Cheng, Zhengdong

    2017-03-01

    Asymmetric Janus and Gemini ZrP-PNIPAM monolayer nanoplates were obtained by exfoliation of two-dimensional layered ZrP disks whose surface was covalently modified with thermosensitive polymer PNIPAM. The nanoplates largely reduced interfacial tension (IFT) of the oil/water interface so that they were able to produce stable oil/water emulsions, and the PNIPAM grafting either on the surface or the edge endowed the nanoplates rapid temperature responsivity. The ZrP-PNIPAM nanoplates proved to be thermosensitive Pickering emulsifiers for controlled-release applications.

  6. Biological Effects of Drug-Free Alginate Beads Cross-Linked by Copper Ions Prepared Using External Ionotropic Gelation.

    PubMed

    Pavelková, M; Kubová, K; Vysloužil, J; Kejdušová, M; Vetchý, D; Celer, V; Molinková, D; Lobová, D; Pechová, A; Vysloužil, J; Kulich, P

    2016-08-08

    External ionotropic gelation offers a unique possibility to entrap multivalent ions in a polymer structure. The aim of this experimental study was to prepare new drug-free sodium alginate (ALG) particles cross-linked by Cu(2+) ions and to investigate their technological parameters (particle size, sphericity, surface topology, swelling capacity, copper content, release of Cu(2+) ions, mucoadhesivity) and biological activity (cytotoxicity and efficiency against the most common vaginal pathogens-Herpes simplex, Escherichia coli, Candida albicans) with respect to potential vaginal administration. Beads prepared from NaALG dispersions (3 or 4%) were cross-linked by Cu(2+) ions (0.5 or 1.0 M CuCl2) using external ionotropic gelation. Prepared mucoadhesive beads with particle size over 1000 μm exhibited sufficient sphericity (all ˃0.89) and copper content (214.8-249.07 g/kg), which increased with concentration of polymer and hardening solution. Dissolution behaviour was characterized by extended burst effect, followed by 2 h of copper release. The efficiency of all samples against the most common vaginal pathogens was observed at cytotoxic Cu(2+) concentrations. Anti-HSV activity was demonstrated at a Cu(2+) concentration of 546 mg/L. Antibacterial activity of beads (expressed as minimum inhibition concentration, MIC) was influenced mainly by the rate of Cu(2+) release which was controlled by the extent of swelling capacity. Lower MIC values were found for E. coli in comparison with C. albicans. Sample ALG-3_1.0 exhibited the fastest copper release and was proved to be the most effective against both bacteria. This could be a result of its lower polymer concentration in combination with smaller particle size and thus larger surface area.

  7. The Chemical Behavior of Fluids Released during Deep Subduction Based on Fluid Inclusions

    NASA Astrophysics Data System (ADS)

    Frezzotti, M. L.; Ferrando, S.

    2014-12-01

    We present a review of current research on fluid inclusions in (HP-) UHP metamorphic rocks that, combined with existing experimental research and thermodynamic models, allow us to investigate the chemical and physical properties of fluids released during deep subduction, their solvent and element transport capacity, and the subsequent implications for the element recycling in the mantle wedge. An impressive number of fluid inclusion studies indicate three main populations of fluid inclusions in HP and UHP metamorphic rocks: i) aqueous and/or non-polar gaseous fluid inclusions (FI), ii) multiphase solid inclusions (MSI), and iii) melt inclusions (MI). Chemical data from preserved fluid inclusions in rocks match with and implement "model" fluids by experiments and thermodynamics, revealing a continuity behind the extreme variations of physico-chemical properties of subduction-zone fluids. From fore-arc to sub-arc depths, fluids released by progressive devolatilization reactions from slab lithologies change from relatively diluted chloride-bearing aqueous solutions (± N2), mainly influenced by halide ligands, to (alkali) aluminosilicate-rich aqueous fluids, in which polymerization probably governs the solubility and transport of major (e.g., Si and Al) and trace elements (including C). Fluid inclusion data implement the petrological models explaining deep volatile liberation in subduction zones, and their flux into the mantle wedge.

  8. Numerical investigation on three-dimensional dispersion and conversion behaviors of silicon tetrachloride release in the atmosphere.

    PubMed

    Jianwen, Zhang; Xinxin, Yin; Yanan, Xin; Jian, Zhang; Xiaoping, Zheng; Chunming, Jiang

    2015-05-15

    The world has experienced heavy thirst of energy as it has to face a dwindling supply of fossil fuel and polycrystalline silicon photovoltaic solar energy technology has been assigned great importance. Silicon tetrachloride is the main byproducts of polysilicon industry, and it's volatile and highly toxic. Once silicon tetrachloride releases, it rapidly forms a dense gas cloud and reacts violently with water vapor in the atmosphere to form a gas cloud consisting of the mixture of silicon tetrachloride, hydrochloric acid and silicic acid, which endangers environment and people. In this article, numerical investigation is endeavored to explore the three dimensional dispersion and conversion behaviors of silicon tetrachloride release in the atmosphere. The k-ϵ model with buoyancy correction on k is applied for turbulence closure and modified EBU model is applied to describe the hydrolysis reaction of silicon tetrachloride. It is illustrated that the release of silicon tetrachloride forms a dense cloud, which sinks onto the ground driven by the gravity and wind and spreads both upwind and downwind. Complicated interaction occurs between the silicon tetrachloride cloud and the air mass. The main body of the dense cloud moves downwind and reacts with the water vapor on the interface between the dense cloud and the air mass to generate a toxic mixture of silicon tetrachloride, hydrogen chloride and silicic acid. A large coverage in space is formed by the toxic mixture and imposes chemical hazards to the environment. The exothermic hydrolysis reaction consumes water and releases reaction heat resulting in dehydration and temperature rise, which imposes further hazards to the ecosystem over the affected space.

  9. Spot the difference: engineered and natural nanoparticles in the environment--release, behavior, and fate.

    PubMed

    Wagner, Stephan; Gondikas, Andreas; Neubauer, Elisabeth; Hofmann, Thilo; von der Kammer, Frank

    2014-11-10

    The production and use of nanoparticles leads to the emission of manufactured or engineered nanoparticles into the environment. Those particles undergo many possible reactions and interactions in the environment they are exposed to. These reactions and the resulting behavior and fate of nanoparticles in the environment have been studied for decades through naturally occurring nanoparticulate (1-100 nm) and colloidal (1-1000 nm) substances. The knowledge gained from these investigations is nowhere near sufficiently complete to create a detailed model of the behavior and fate of engineered nanoparticles in the environment, but is a valuable starting point for the risk assessment of these novel materials. It is the aim of this Review to critically compare naturally observed processes with those found for engineered systems to identify the "nanospecific" properties of manufactured particles and describe critical knowledge gaps relevant for the risk assessment of manufactured nanomaterials in the environment.

  10. Individuals with Threatening or Violent Criminal Behavior: Civil Commitment or Release After Incarceration?

    PubMed Central

    Mariano, Maria Theresa; Grace, Jeffery; Distefano, Diane J.; Olympia, Josie L.; Watson, Thomas

    2011-01-01

    Patients who have diagnoses of a major mental illness and an antisocial personality disorder present administrative, clinical, legal, and ethical challenges. Based on an actual case, the authors discuss how clinicians could fulfill the obligation to the patient, mental health system, judicial system, and the community under these circumstances. We explore how clinical presentation of symptomatology and criminal behavior contribute to challenges in determining psychiatric care. PMID:21779539

  11. Individuals with threatening or violent criminal behavior: civil commitment or release after incarceration?

    PubMed

    Mariano, Maria Theresa; Grace, Jeffery; Trigoboff, Eileen; Distefano, Diane J; Olympia, Josie L; Watson, Thomas

    2011-06-01

    Patients who have diagnoses of a major mental illness and an antisocial personality disorder present administrative, clinical, legal, and ethical challenges. Based on an actual case, the authors discuss how clinicians could fulfill the obligation to the patient, mental health system, judicial system, and the community under these circumstances. We explore how clinical presentation of symptomatology and criminal behavior contribute to challenges in determining psychiatric care.

  12. Preparation of a magnetic-field-sensitive hydrogel and preliminary study of its drug release behavior.

    PubMed

    Namdeo, Mini; Bajpai, S K; Kakkar, S

    2009-01-01

    The study describes the in situ formation of magnetite nanoparticles within a swollen polyacrylamide hydrogel. The average diameter of nanoparticles, as determined by TEM analysis, was found to be nearly 12.5 nm. In XRD analysis the characteristic peaks, observed at d = 3.07, 2.78, 2.64, 2.53, 2.32 and 2.03, also confirmed the formation of magnetite within the polymer network. The percent swelling of magnetite-loaded gel in physiological fluid was observed to decrease with increasing amount of magnetite in the gel. Moreover, the percent swelling increased from 140 to 254% as the strength of the applied magnetic field increased from 500 to 2500 Oe. Finally, the model drug, vitamin B(2), loaded magnetic gels showed relatively slower release in the presence of an applied magnetic field.

  13. Acute central administration of immepip, a histamine H3 receptor agonist, suppresses hypothalamic histamine release and elicits feeding behavior in rats.

    PubMed

    Chiba, Seiichi; Itateyama, Emi; Sakata, Toshiie; Yoshimatsu, Hironobu

    2009-04-06

    Histamine suppresses feeding behavior via histamine H1 receptors in the hypothalamus. This study was performed to examine whether the acute reduction of histamine release in the hypothalamus caused by immepip, a histamine H3 agonist, modulates the feeding behavior of rats. Rats had a catheter implanted in the third cerebral ventricle (i3v) and were given central injections of phosphate-buffered-saline or immepip (100-300 pmol/rat). Following the i3v administration of immepip, the rats developed dose-dependent hypokinesia within 10 min of administration. Next to hypokinesia, the rats showed significant dose-dependent feeding behavior. High-performance liquid chromatography (HPLC) confirmed the reduction in histamine release in the hypothalamus of rats following i3v administration of immepip. These results suggest that i3v administration of immepip, an H3 receptor agonist, suppresses hypothalamic histamine release and elicits feeding behavior in rats.

  14. Oxygenated gasoline release in the unsaturated zone - Part 1: Source zone behavior.

    PubMed

    Freitas, Juliana G; Barker, James F

    2011-11-01

    Oxygenates present in gasoline, such as ethanol and MTBE, are a concern in subsurface contamination related to accidental spills. While gasoline hydrocarbon compounds have low solubility, MTBE and ethanol are more soluble, ethanol being completely miscible with water. Consequently, their fate in the subsurface is likely to differ from that of gasoline. To evaluate the fate of gasoline containing oxygenates following a release in the unsaturated zone shielded from rainfall/recharge, a controlled field test was performed at Canadian Forces Base Borden, in Ontario. 200L of a mixture composed of gasoline with 10% ethanol and 4.5% MTBE was released in the unsaturated zone, into a trench 20cm deep, about 32cm above the water table. Based on soil cores, most of the ethanol was retained in the source, above the capillary fringe, and remained there for more than 100 days. Ethanol partitioned from the gasoline to the unsaturated pore-water and was retained, despite the thin unsaturated zone at the site (~35cm from the top of the capillary fringe to ground surface). Due to its lower solubility, most of the MTBE remained within the NAPL as it infiltrated deeper into the unsaturated zone and accumulated with the gasoline on top of the depressed capillary fringe. Only minor changes in the distribution of ethanol were noted following oscillations in the water table. Two methods to estimate the capacity of the unsaturated zone to retain ethanol are explored. It is clear that conceptual models for sites impacted by ethanol-fuels must consider the unsaturated zone.

  15. The olfactory organ modulates gonadotropin-releasing hormone types and nest-building behavior in the tilapia Oreochromis niloticus.

    PubMed

    Uchida, Hiroshi; Ogawa, Satoshi; Harada, Mina; Matushita, Masato; Iwata, Munehico; Sakuma, Yasuo; Parhar, Ishwar S

    2005-10-01

    Direct olfactory inputs to any of the known gonadotropin-releasing hormone (GnRH) containing neurons have not been demonstrated. Therefore, the rationale of this study was to examine whether olfactory inputs might in some way interact with the GnRH system(s) to synchronize reproductive behaviors. In order to establish this, we used anosmic mature male tilapia to investigate changes in reproductive behaviors, gonadal morphology, and GnRH1, GnRH2, and GnRH3 cellular morphology and change in GnRH mRNA levels by real-time polymerase chain reaction. Bilateral removal of the olfactory rosettes followed by occlusion of the nasal cavity (ORX) inhibited nest-building behavior, but had no effect on aggressive and sexual behaviors or gonadal morphology. ORX failed to alter the morphological features of GnRH1, GnRH2, and GnRH3 (cell number, size, GnRH optical density), but significantly decreased copies of GnRH1 and GnRH2 mRNAs. GnRH immunoreactive fibers were not evident in the olfactory nerve and rosettes. DiI application to the olfactory nerve labeled inputs primarily to the glomerular layer of the olfactory bulbs and extrabulbar inputs to the forebrain but not to GnRH neurons. These results provide evidence that the olfactory rosette is crucial for modulating nest-building behavior through second-order olfactory pathways interacting with GnRH1 and GnRH2 neuronal systems.

  16. Gender and risk behaviors for HIV and sexually transmitted infections among recently released inmates: A prospective cohort study.

    PubMed

    Binswanger, Ingrid A; Mueller, Shane R; Beaty, Brenda L; Min, Sung-joon; Corsi, Karen F

    2014-01-01

    Women in prison have a higher prevalence of HIV than men. After release from prison, former inmates have the opportunity to engage in risk behaviors for HIV and other sexually transmitted infections (STIs). We sought to assess change in risk behaviors over time and the association of gender with risk behavior in the postrelease period. In this prospective cohort study, we interviewed 200 former inmates (51 women) approximately two weeks (baseline) and three months (follow-up) after release and tested them for HIV infection at follow-up. We examined the association of gender with unprotected vaginal or anal sex in the last seven days using chi-square and Fisher's exact tests and multivariable logistic regression. At baseline, 22% of men and 41% of women reported unprotected vaginal sex (p < 0.01) and 5% of men and 8% of women reported unprotected anal sex (p = 0.51). Being younger (OR for each decade increase 0.48, 95% CI = 0.29-0.80), being gay/lesbian or being bisexual (compared with being heterosexual, OR = 4.74, 95% CI = 1.01-22.17 and OR = 3.98, 95% CI = 1.41-11.26, respectively), or reporting a drug of choice of heroin/speedballs or cocaine/crack (compared with marijuana/no drug of choice, OR = 24.00, 95% CI = 5.15-111.81 and OR = 3.49, 95% CI = 1.20-10.18, respectively) was associated with unprotected vaginal or anal sex after adjusting for race, homelessness, and hazardous drinking. At follow-up, 21% of men and 44% of women reported unprotected sex (p = 0.005), and female gender (OR = 4.42, 95% CI = 1.79-10.94) and hazardous drinking (compared with not meeting criteria for hazardous drinking, OR = 3.64, 95% CI = 1.34-9.86) were associated with unprotected sex, adjusting for race and homelessness. In this population with a high prevalence of HIV, we demonstrated persistent engagement in sexual risk behavior during the postrelease period. Enhanced efforts to promote sexual health and reduced risk behavior among both male and female current and former prison

  17. Experimental study of the removal of copper ions using hydrogels of xanthan, 2-acrylamido-2-methyl-1-propane sulfonic acid, montmorillonite: Kinetic and equilibrium study.

    PubMed

    Aflaki Jalali, Marzieh; Dadvand Koohi, Ahmad; Sheykhan, Mehdi

    2016-05-20

    In this paper, removal of copper ions from aqueous solution using novel xanthan gum (XG) hydrogel, xanthan gum-graft-2-acrylamido-2-methyl-1-propane sulfonic acid (XG-g-P(AMPS)) hydrogel and xanthan gum-graft-2-acrylamido-2-methyl-1-propane sulfonic acid/montmorillonite (XG-g-P(AMPS)/MMT) hydrogel composite were studied. The structure and morphologies of the xanthan-based hydrogels were characterized by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscope (SEM). Adsorbents comprised a porous crosslink structure with side chains that carried carboxyl, hydroxyl and sulfonate. Maximum adsorption was observed in the pH=5.2, initial concentrations of Cu(2+)=321.8 mg/L, Temperature=45 °C, contact time=5 h with 0.2 g/50 mL of the hydrogels. Adsorption process was found to follow Langmuir isotherm model with maximum adsorption capacity of 24.57, 39.06 and 29.49 mg/g for the XG, XG-g-P(AMPS) and XG-g-P(AMPS)/MMT, respectively. Adsorption kinetics data fitted well with pseudo second order model. The negative ΔG° values and the positive ΔS° confirmed that the adsorption was a spontaneous process. The positive ΔH° values suggested that the adsorption was endothermic in nature.

  18. One-pot fabrication of FRET-based fluorescent probe for detecting copper ion and sulfide anion in 100% aqueous media

    NASA Astrophysics Data System (ADS)

    Lv, Kun; Chen, Jian; Wang, Hong; Zhang, Peisheng; Yu, Maolin; Long, Yunfei; Yi, Pinggui

    2017-04-01

    The design of effective tools for detecting copper ion (Cu2 +) and sulfide anion (S2 -) is of great importance due to the abnormal level of Cu2 + and S2 - has been associated with an increase in risk of many diseases. Herein, we report on the fabrication of fluorescence resonance energy transfer (FRET) based fluorescent probe PF (PEI-FITC) for detecting Cu2 + and S2 - in 100% aqueous media via a facile one-pot method by covalent linking fluorescein isothiocyanate (FITC) with branched-polyethylenimine (b-PEI). PF could selectively coordinate with Cu2 + among 10 metal ions to form PF-Cu2 + complex, resulting in fluorescence quenching through FRET mechanism. Furthermore, the in situ generated PF-Cu2 + complex can be used to selectively detect S2 - based on the displacement approach, resulting in an off-on type sensing. There is no obvious interference from other anions, such as Cl-, NO3-, ClO4-, SO42 -, HCO3-, CO32 -, Br-, HPO42 -, F- and S2O32 -. In addition, PF was successfully used to determine Cu2 + and S2 - in human serum and tap water samples. Therefore, the FRET-based probe PF may provide a new method for selective detection of multifarious analysts in biological and environmental applications, and even hold promise for application in more complicated systems.

  19. Micellar-enhanced ultrafiltration of copper ions using sodium dodecyl sulfate and its mixture with Brij 35, Tween 80 and Triton X-100.

    PubMed

    Zhao, Baowei; Li, Ruirui; Zhong, Jinkui; Zhang, Li

    2013-01-01

    The performance of copper ion removal using sodium dodecyl sulfate (SDS) and its mixtures with Brij 35, Tween 80 (TW80) and Triton X-100 (TX100) by micellar-enhanced ultrafiltration (MEUF) was investigated. The effects of the molar ratio of nonionic surfactant to SDS on the critical micelle concentration (CMC) of SDS/Brij 35, SDS/TW80 and SDS/TX100, the removal efficiency of Cu(2+), the residual concentration of SDS in the permeate solution and the permeate flux were tested. The results showed that the CMCs of the mixed surfactants were sharply less than that of pure SDS. The removal efficiencies of Cu(2+) were up to the maximum values 98.3 and 95.8% when the molar ratios of Brij 35 and TW80 to SDS were 0.3, and it was 93.5% given 0.7 molar ratio of TX100 to SDS. The concentration of SDS in the permeate decreased dramatically with the addition of nonionic surfactant, and the permeate flux decreased slightly as the molar ratio increased. Compared with the performance by single SDS, the mixed SDS/Brij 35, SDS/TW80 and SDS/TX100 at an optimum composition could result in not only higher rejection of Cu(2+) but also much less dosage of surfactant and concentration of SDS in the permeate.

  20. Electrochemical detection of copper ions leached from CuO nanoparticles in saline buffers and biological media using a gold wire working electrode

    NASA Astrophysics Data System (ADS)

    Baldisserri, Carlo; Costa, Anna Luisa

    2016-04-01

    We performed explorative cyclic voltammetry in phosphate-buffered saline buffers, Dulbecco's modified Eagle's medium (DMEM), and fetal bovine serum-added DMEM using Au wire as working electrode, both in the absence and in the presence of known nominal concentrations of Cu2+ ions or 15 nm CuO nanoparticles. Addition of either Cu2+ ions or aqueous suspension of CuO nanoparticles caused a single anodic peak to appear in the double-layer region of all three pristine media. The height of the anodic peak was found to increase in a monotonic fashion vs. Cu2+ concentration in Cu2+-added media, and versus time since CuO addition in CuO-added media. Stepwise addition of glycine to Cu2+-added phosphate-buffered saline buffer caused an increasing cathodic shift of the anodic peak accompanied by decreasing peak currents. Results indicate that preparing Cu2+-free suspensions of CuO nanoparticles in such media is difficult, owing to the presence of leached copper ions. The implications on results of experiments in which CuO nanoparticle-added biological media are used as cell culture substrates are discussed. Literature data on the interactions between Cu2+ ions, dissolved carbon dioxide in aqueous CuO suspensions, and amino acids present in such media are compared to our results.

  1. Detection and investigation of the molecular nature of low-molecular-mass copper ions in isolated rheumatoid knee-joint synovial fluid.

    PubMed

    Naughton, D P; Knappitt, J; Fairburn, K; Gaffney, K; Blake, D R; Grootveld, M

    1995-03-20

    Low-molecular-mass copper(II) species have been detected and quantified in ultrafiltrates (n = 7) of rheumatoid synovial fluid (SF) by a highly-sensitive HPLC-based assay system with the ability to determine Cu(II) concentrations of < 10(-7) mol.dm-3. High field 1H NMR spectroscopy demonstrated that addition of Cu(II)(aq.) to isolated samples of RA SF ultrafiltrates resulted in complexation by histidine > alanine > formate > threonine > lactate > tyrosine > phenylalanine, their effectiveness in this context being in the given order. CD spectra of Cu(II)-treated samples of intact SF exhibited absorption bands typical of copper(II)-albumin complexes, in addition to a band attributable to a low-molecular-mass histidinate complex (lambda min 610 nm). Since both albumin and histidine are potent radical scavengers, these results indicate that any .OH radical generated from bound copper ions will be 'site-specifically' scavenged. Hence, low-molecular-mass copper complexes with the ability to promote the generation of .OH radical which can then escape from the metal ion co-ordination sphere (and in turn, cause damage to critical biomolecules) appear to be absent from inflammatory SF.

  2. Spectroscopic features of copper ions in multi-component Na2Osbnd PbOsbnd Bi2O3sbnd SiO2 glass ceramics

    NASA Astrophysics Data System (ADS)

    Sambasiva Rao, M. V.; Suresh, S.; Narendrudu, T.; Suneel Kumar, A.; Chinna Ram, G.; Krishna Rao, D.

    2016-12-01

    Multi-component Na2Osbnd PbOsbnd Bi2O3sbnd SiO2 glasses were crystallised with different CuO contents (0-1 mol % in steps of 0.2) as nucleating agent. These glass ceramics were characterized by XRD, SEM and DTA techniques and indicated the samples contain well defined and randomly distributed grains of different crystalline phases. Spectroscopic studies viz., optical absorption, EPR, FTIR and Raman were also carried out on these glass ceramics. The broad absorption band observed in the wavelength region 550-1000 nm in these glass ceramics and is the characteristic of Cu2+ ions. Optical absorption and EPR studies suggest that Cu2+ ions enter into the lattice as tetragonally distorted octahedral symmetry for which the bonding parameters were evaluated. FTIR and Raman spectra give important information about the nature of various structural units in the glass ceramic matrix. The analysis of these spectroscopic investigations reveals that with increase in the concentration of nucleating agent CuO, copper ions exist in Cu2+ state they act as modifiers and increases the degree of disorder in the glass ceramic network.

  3. Implantable biodegradable sponges: effect of interpolymer complex formation of chitosan with gelatin on the release behavior of tramadol hydrochloride.

    PubMed

    Foda, Nagwa H; El-laithy, Hanan M; Tadros, Mina I

    2007-01-01

    The effect of interpolymer complex formation between positively charged chitosan and negatively charged gelatin (Type B) on the release behavior of tramadol hydrochloride from biodegradable chitosan-gelatin sponges was studied. Mixed sponges were prepared by freeze-drying the cross-linked homogenous stable foams produced from chitosan and gelatin solutions where gelatin acts as a foam builder. Generation of stable foams was optimized where concentration, pH of gelatin solution, temperature, speed and duration of whipping process, and, chitosan-gelatin ratio drastically affect the properties and the stability of the produced foams. The prepared sponges were evaluated for their morphology, drug content, and microstructure using scanning electron microscopy, mechanical properties, uptake capacity, drug release profile, and their pharmacodynamic activity in terms of the analgesic effect after implantation in Wistar rats. It was revealed that whipping 7% (w/w) gelatin solution, of pH 5.5, for 15 min at 25 degrees C with a stirring speed of 1000 rpm was the optimum conditions for stable gelatin foam generation. Moreover, homogenous, uniform chitosan-gelatin foam with small air bubbles were produced by mixing 2.5% w/w chitosan solution with 7% w/w gelatin solution in 1:5 ratio. Indeed, polyionic complexation between chitosan and gelatin overcame the drawbacks of chitosan sponge mechanical properties where, pliable, soft, and compressible sponge with high fluid uptake capacity was produced at 25 degrees C and 65% relative humidity without any added plasticizer. Drug release studies showed a successful retardation of the incorporated drug where the t50% values of the dissolution profiles were 0.55, 3.03, and 4.73 hr for cross-linked gelatin, un-cross-linked chitosan-gelatin, and cross-linked chitosan-gelatin sponges, respectively. All the release experiments followed Higuchi's diffusion mechanism over 12 hr. The achieved drug prolongation was a result of a combined effect

  4. Behavior of 131I and 137Cs in environments released from the Fukushima nuclear disaster

    NASA Astrophysics Data System (ADS)

    Ohta, T.; Mahara, Y.; Kubota, T.; Igarashi, T.

    2011-12-01

    The devastating tsunami that caused by the great earthquake (M = 9.0) off the coast of northeastern Honshu on 11 March 2011 destroyed large coastal areas of Tohoku and north Kanto, Japan. Radionuclides, including 131I, 134Cs, and 137Cs, were released into the atmosphere from the Fukushima Daiichi plants. Concentration of levels of 131I, 134Cs, and 137Cs in Ibaraki Prefecture, Japan, released from the Fukushima Daiichi plant were investigated in the soil and precipitation. The concentrations of 131I and 137Cs in the soil from the surface to 1 cm depth in Ibaraki Prefecture were 9360-13,400 Bq/kg and 720-3250 Bq/kg, respectively. The concentration of 137Cs at this soil observation site originating from the Fukushima plant was 8.4 to 21 times that found locally after the Nagasaki atomic bomb explosion. Most of the 134Cs and 137Cs from rainwater were trapped by the surface soil and sand to a depth of 1 cm, whereas only about 30% of the 131I was collected by the surface soil, suggesting that 131I would move deeper than 137Cs and 134Cs. The 131I in the rainwater was in the anion exchangeable form, and all of it could be collected by anion exchangeable mechanisms, whereas 30% of the 131I that had passed through the soil could not be trapped by the anion exchange resin, suggesting that the chemical form of this 30% was in a changeable, organic-bound form. The 131I, 134Cs, and 137Cs that were absorbed on soil were difficult to be dissolved into water. As the half-life of 131I is short and 137Cs is strongly adsorbed on the surface soil and sand, these radionuclides would be unlikely to reach the groundwater before completely decaying; contamination of groundwater with 131I and 137Cs supplied from rainwater to the surface soil is therefore exceedingly unlikely. As the 137Cs is likely to migrate only 0.6 cm in 10 years, people living in the Fukushima and Kanto areas will be exposed to radiation from 137Cs in the surface soil and sand. For protection, surface soils and sands

  5. α-Tocopherol-loaded niosome prepared by heating method and its release behavior.

    PubMed

    Basiri, Ladan; Rajabzadeh, Ghadir; Bostan, Aram

    2017-04-15

    α-Tocopherol-loaded niosome was developed using modified heating method. The influence of surfactants (Span60 and Tween60) in different mole ratios, presence or absence of cholesterol (Chol) and dicetyl phosphate (DCP) as well as different concentration of α-tocopherol (α-TOC) on mean size, polydispersity index, zeta potential and entrapment efficiency (EE) was evaluated. The results showed that α-TOC loaded niosomes exhibited a small mean size (73.85±0.6-186±0.58nm), narrow size distribution and high EE (61.13±0.52-98.92±0.92). By decreasing the HLB, the EE and stability of the niosomes increased. The DCP and Chol improved the physicochemical properties of niosomes. 3:1 mole ratio of Span 60:Tween 60, 4mg/ml of α-TOC and 25:12.5:2.5 mole ratio of surfactant:Chol:DCP was the optimum formulation in the encapsulation of α-TOC applying niosome system. The niosomes had sustained release profile in the simulated gastric and intestinal fluid.

  6. Creep rupture behavior of polypropylene suture material and its applications as a time-release mechanism

    SciTech Connect

    Kusy, R.P.; Whitley, J.Q.

    1983-05-01

    The controlled failure of polypropylene (PP) sutures is studied via creep rupture tests. From plots of log time (tB) vs. stress (sigma), linear relationships are generated over the failure times of 1-1000 h. Results show that as a function of stress, the time dependence varies with irradiation dose (15, 20, 25, and 50 Mrad), irradiation atmosphere (air and vacuum), suture diameter (7-0, 6-0, 5-0, and 4-0), and test temperature (26 and 37 degrees C). For a given stress, the time to failure is least for the greatest dose in the presence of air and at the highest temperature. When suture loops are wrapped around a small wire sheave, however, failure occurs in the largest suture as much as two decades sooner than the smallest suture studied. Within the limitations stated herein, they are independent of test method, loop diameter, aging, and humidity. Consequently, after irradiation in vacuum and postirradiation heat treatment, the processed material may be stored at room temperature for at least 1 month. Such materials are advocated when the time release of a dental or medical device is required, for example, in the self-activating cleft palate appliance.

  7. Direct behavioral evidence that unique bile acids released by larval sea lamprey (Petromyzon marinus) function as a migratory pheromone

    USGS Publications Warehouse

    Bjerselius , Rickard; Li, Weiming; Teeter, John H.; Seelye, James G.; Johnson, Peter B.; Maniak, Peter J.; Grant, Gerold C.; Polkinghorne, Christine N.; Sorensen, Peter W.

    2000-01-01

    Four behavioral experiments conducted in both the laboratory and the field provide evidence that adult sea lamprey (Petromyzon marinus) select spawning rivers based on the odor of larvae that they contain and that bile acids released by the larvae are part of this pheromonal odor. First, when tested in a recirculating maze, migratory adult lamprey spent more time in water scented with larvae. However, when fully mature, adults lost their responsiveness to larvae and preferred instead the odor of mature individuals. Second, when tested in a flowing stream, migratory adults swam upstream more actively when the water was scented with larvae. Third, when migratory adults were tested in a laboratory maze containing still water, they exhibited enhanced swimming activity in the presence of a 0.1 nM concentration of the two unique bile acids released by larvae and detected by adult lamprey. Fourth, when adults were exposed to this bile acid mixture within flowing waters, they actively swam into it. Taken together, these data suggest that adult lamprey use a bile acid based larval pheromone to help them locate spawning rivers and that responsiveness to this cue is influenced by current flow, maturity, and time of day. Although the precise identity and function of the larval pheromone remain to be fully elucidated, we believe that this cue will ultimately prove useful as an attractant in sea lamprey control.

  8. pH-responsive release behavior and anti-bacterial activity of bacterial cellulose-silver nanocomposites.

    PubMed

    Shao, Wei; Liu, Hui; Liu, Xiufeng; Sun, Haijun; Wang, Shuxia; Zhang, Rui

    2015-05-01

    Bacterial cellulose (BC) has been extensively explored as some of the most promising biomaterials for biomedical applications due to their unique properties, such as high crystallinity, high mechanical strength, ultrafine fiber network structure, good water holding capacity and biocompatibility. However, BC is lack of anti-bacterial activity which is the main issue to be solved. In the study, BC-Ag nanocomposites were prepared in situ by introducing silver nanoparticles (AgNPs) into BC acting as the templates. The BC and as-prepared BC-Ag nanocomposites were characterized by several techniques including scanning electron microscope, Fourier transform infrared spectra, ultraviolet-visible absorption spectra, X-ray diffraction and thermogravimetric analyses. These results indicate AgNPs successfully impregnated into BC. The releases of Ag(+) at different pH values were studied, which showed pH-responsive release behaviors of BC-Ag nanocomposites. The anti-bacterial performances of BC-Ag nanocomposites were evaluated with Escherichia coli ATCC 25922, Staphylococcus aureus ATCC 6538, Bacillus subtilis ATCC 9372 and Candida albicans CMCC(F) 98001, which frequently causes medical associated infections. The experimental results showed BC-Ag nanocomposites have excellent anti-bacterial activities, thus confirming its utility as potential wound dressings.

  9. Impaired GABA synthesis, uptake and release are associated with depression-like behaviors induced by chronic mild stress

    PubMed Central

    Ma, K; Xu, A; Cui, S; Sun, M-R; Xue, Y-C; Wang, J-H

    2016-01-01

    Major depression is a prevalent emotion disorder. Chronic stressful life in genetically susceptible individuals is presumably a major etiology that leads to neuron and synapse atrophy in the limbic system. Molecular mechanisms underlying the pathological changes remain elusive. Mice were treated by chronic unpredictable mild stress (CUMS) until they demonstrated depression-like behavior. GABA release in the medial prefrontal cortex was evaluated by cell electrophysiology and imaging. Molecular profiles related to GABA synthesis and uptake were investigated by the high-throughput sequencings of microRNAs and mRNAs as well as western blot analysis in this cortical area. In CUMS-induced depression mice, there appear the decreases in the innervation and function of GABAergic axons and in the levels of mRNAs and proteins of glutamate decarboxylase-67, vesicular GABA transporter and GABA transporter-3. miRNA-15b-5p, miRNA-144-3p, miRNA-582-5p and miRNA-879-5p that directly downregulate such mRNAs increase in this cortex. Our results suggest that chronic mild stress impairs GABA release and uptake by upregulating miRNAs and downregulating mRNAs and proteins, which may constitute the subcellular and molecular mechanisms for the lowered GABA tone in major depression. PMID:27701406

  10. Behavior and Release of Nitrogen at Mines and Quarries in Nordic Conditions

    NASA Astrophysics Data System (ADS)

    Karlsson, Teemu; Neitola, Raisa; Jermakka, Johannes; Merta, Elina; Mroueh, Ulla-Maija

    2015-04-01

    The increased extraction of mineral resources and mining activities creates added pressure on the environmental issues and a proper water management in mining areas in Finland. Among others, nitrogen compounds released from explosives or from mining processes can have a detrimental effect on the environment. Thus, this project aimed at comprehensive understanding on the nitrogen issue in the extractive industry. The project collected essential data on nitrogen compounds present in the environments of mines and quarries, and generated better understanding of the discharge and behaviour of nitrogen compounds in mining areas. The sources and balances of explosives-originated nitrogen compounds at mines and quarries of different sizes were investigated and compared. Additionally, the focus was in 'nitrogen smudging' problem of waste rocks and the intensity, as well as evolution and chemical characteristics of their nitrogen contamination. According to the results, the total load of potential nitrogen to the environment depends on the scale and type of the activity as well as the type of explosives used. The main emission sources of nitrogen are process and dewatering waters. A lysimeter study showed that the explosives originated nitrogen content of left over stones from natural stone quarrying is relatively low and ca. half of the nitrogen is leached within the first weeks after detonation. The "nitrogen smudging" of natural stone quarrying left over stones is relatively low to begin with and enhanced by the rapid flushing by rainwater, thus the residues of explosives should not be considered to prevent the utilization of otherwise mineralogically inert waste rocks of good technical quality. The overall nitrogen management should take into account the background concentrations and sensitivity of the local ecosystem. The research project "Solution for Control of Nitrogen Discharges at Mines and Quarries, (MINIMAN)" was realized during years 2012-2014 as a cooperative

  11. Impact of physicochemical properties of porous silica materials conjugated with dexamethasone via pH-responsive hydrazone bond on drug loading and release behavior

    NASA Astrophysics Data System (ADS)

    Numpilai, Thanapha; Witoon, Thongthai; Chareonpanich, Metta; Limtrakul, Jumras

    2017-02-01

    The conjugation of dexamethasone (DEX) onto modified-porous silica materials via a pH-responsive hydrazone bond has been reported to be highly efficient method to specifically deliver the DEX to diseased sites. However, the influence of physicochemical properties of porous silica materials has not yet been fully understood. In this paper, the impact of pore sizes, particle sizes and silanol contents on surface functionalization, drug loading and release behavior of porous silica materials conjugated with dexamethasone via pH-responsive hydrazone bond was investigated. The grafting density was found to relate to the number of silanol groups on the surface of porous silica materials. The particle size and macropores of the porous silica materials played an vital role on the drug loading and release behavior. Although the porous silica materials with larger particle sizes possessed a lower grafting density, a larger amount of drug loading could be achieved. Moreover, the porous silica materials with larger particle sizes showed a slower release rate of DEX due to a longer distance for cleaved DEX diffusion out of pores. DEX release rate exhibited pH-dependent, sustained release. At pH 4.5, the amount of DEX release within 10 days could be controlled in the range of 12.74-36.41%, depending on the host material. Meanwhile, less than 1.5% of DEX was released from each of type of the porous silica materials at pH 7.4. The results of silica dissolution suggested that the degradation of silica matrix did not significantly affect the release rate of DEX. In addition, the kinetic modeling studies revealed that the DEX releases followed Korsmeyer-Peppas model with a release exponent (n) ranged from 0.3 to 0.47, indicating a diffusion-controlled release mechanism.

  12. Toxicity of different-sized copper nano- and submicron particles and their shed copper ions to zebrafish embryos.

    PubMed

    Hua, Jing; Vijver, Martina G; Ahmad, Farooq; Richardson, Michael K; Peijnenburg, Willie J G M

    2014-08-01

    Three sizes of copper nanoparticles (Cu NPs; 25 nm, 50 nm, and 100 nm), 1 submicron-sized particle, and Cu(NO3 )2 were added to the culture buffer of zebrafish embryos from 24 h postfertilization to 120 h postfertilization. In suspensions of Cu NPs and the Cu submicron-sized particle, the main contribution to the toxicity to zebrafish embryos was from the particle form of Cu particles (Cu NPparticle , >71%) rather than from dissolved Cu from the Cu particles (Cu NPion ). All particles tested as well as copper nitrate inhibited hatching, altered behavioral responses, and increased the incidence of malformations. Different kinds of abnormalities were observed in the morphology and behavior of the zebrafish embryos, depending on the particle size of the Cu suspensions tested. The median lethal concentrations of Cu NPparticle (25 nm, 50 nm, and 100 nm), the submicron-sized particle, and copper nitrate were 0.58 mg/L, 1.65 mg/L, 1.90 mg/L, 0.35 mg/L, and 0.70 mg/L, respectively. Submicron-sized particles and copper nitrate were more toxic than Cu NPs, and smaller Cu NPs were more toxic than larger Cu NPs. Dissolution of Cu NPs and the subsequent ion toxicity was not the primary mechanism of Cu NP toxicity in zebrafish embryos.

  13. In vivo dynamical behavior of yeast chromatin modeled as an entangled polymer network with constraint release

    NASA Astrophysics Data System (ADS)

    Wang, Chenxi; Kilfoil, Maria L.

    2013-03-01

    The high fidelity segregation of chromatin is the central problem in cell mitosis. The role of mechanics underlying this, however, is undetermined. Work in this area has largely focused on cytoskeletal elements of the process. Preliminary work in our lab suggests the mechanical properties of chromatin are fundamental in this process. Nevertheless, the mechanical properties of chromatin in the cellular context are not well-characterized. For better understanding of the role of mechanics in this cellular process, and of the chromatin mechanics in vivo generally, a systematic dynamical description of chromatin in vivo is required. Accordingly, we label specific sites on chromatin with fluorescent proteins of different wave lengths, enabling us to detect multiple spots separately in 3D and track their displacements in time inside living yeast cells. We analyze the pairwise cross-correlated motion between spots as a function of relative distance along the DNA contour. Comparison between the reptation model and our data serves to test our conjecture that chromatin in the cell is basically an entangled polymer network under constraints to thermal motion, and removal of constraints by non-thermal cellular processes is expected to affect its dynamic behavior.

  14. Floating-pulsatile release multiparticulate system for chronopharmacotherapy: effect of some hydrophobic additives on the buoyancy and release behavior of particles.

    PubMed

    Maghsoodi, M

    2014-01-01

    A blend of floating and pulsatile principles of a drug delivery system would have the advantage that a drug can be released in the upper gastrointestinal (GI) tract after a lag period, which is anticipated for chronotherapy. In this study, microballoons were prepared by an emulsion solvent diffusion technique using Eudragit S100, and hydrophobic additive (magnesium stearate, stearic acid or talc) for time- and site-specific drug release of piroxicam. The effect of hydrophobic additives on the production yield of floating microparticles, buoyant ability for 8 h, release of drug in simulated GI fluids (simulated gastric fluid [SGF] and simulated intestinal fluid [SIF]), mean particle size, apparent particle density, encapsulation efficiency of drug and physical state of incorporated drug were studied. Both production yield and buoyancy of the microballoons were affected by additives in the following order: magnesium stearate, stearic acid>free-additive>talc. The observed difference in yield and the buoyancy of the microballoons could be attributed to the hydrophobic character of the additives and the shell rigidity of the obtained microballoons. Incorporation of hydrophobic additives in the microballoons was found to impart the desired release properties to the microballoons by providing a 2-phase release pattern with initial slow release (5-6%) through 8 h in SGF followed by rapid pulse release (>92%) in SIF through 15 min. The microballoons co-formulated with magnesium stearate or stearic acid, combining excellent buoyancy and suitable drug release pattern of piroxicam, could be useful in chronopharmacotherapy in arthritis.

  15. Sustained release and standard methylphenidate effects on cognitive and social behavior in children with attention deficit disorder.

    PubMed

    Pelham, W E; Sturges, J; Hoza, J; Schmidt, C; Bijlsma, J J; Milich, R; Moorer, S

    1987-10-01

    Two studies were conducted to investigate the relative effects of sustained release methylphenidate (Ritalin [SR-20]) and standard methylphenidate (Ritalin, 10 mg, administered twice daily). In the first study, 13 boys with attention deficit disorder participating in a summer treatment program went through a double-blind, within-subject trial of each form of methylphenidate and placebo. Measures of social and cognitive behavior were gathered in classroom and play settings. Although group analyses of the data showed that both drugs were effective and there were few differences between them, standard methylphenidate was superior to SR-20 on several important measures of disruptive behavior. Furthermore, analyses of individual responsivity showed clearly that most boys responded more positively to standard methylphenidate than to SR-20. The second study involved a partially overlapping group of nine boys with attention deficit disorder participating in the same summer treatment program. Also double-blind, within-subject, and placebo controlled, this study tracked the time courses of the two forms of methylphenidate. Both were shown to have similar time courses on the Abbreviated Conners Rating Scale and other measures, but SR-20 had a slower onset than did the standard drug form on a continuous performance task. Effects of SR-20 were still evident eight hours after ingestion.

  16. Intracerebroventricular administration of corticotropin-releasing factor antagonist attenuates arousal response accompanied by yawning behavior in rats.

    PubMed

    Kita, Ichiro; Kubota, Natsuko; Yanagita, Shinya; Motoki, Chiharu

    2008-03-15

    We have reported that an arousal response accompanied by yawning behavior can be evoked by electrical and chemical stimulation of the hypothalamic paraventricular nucleus (PVN) in rats, although the mechanism responsible for the arousal response accompanied by yawning evoked by PVN stimulation is still unknown. In the present study, we examined the involvement of corticotropin-releasing factor (CRF) in the arousal response during yawning induced by electrical stimulation of the PVN in anesthetized, spontaneous breathing rats using intracerebroventricular (icv) injection of alpha-helical CRF, a CRF antagonist (4.2 microg, lateral ventricle). The electrocorticogram (ECoG) was recorded to evaluate arousal responses during yawning. Fast Fourier transform was used to obtain the power spectrum in delta (0.5-4 Hz), theta (4-8 Hz), alpha (8-13 Hz), and beta (13-20 Hz) bands. We also recorded the intercostal electromyogram as an index of inspiratory activity and blood pressure (BP) as an index of autonomic function to evaluate yawning response. PVN stimulation induced significant increases in relative powers of theta, alpha, and beta bands, but not delta band, concurrent with yawning events regardless of icv injection, though the relative powers after icv injection of alpha-helical CRF were significantly lower than those after saline injection. These findings suggest that CRF neurons in the PVN are primarily responsible for the arousal response accompanied by yawning behavior.

  17. Predator odor stress alters corticotropin-releasing factor-1 receptor (CRF1R)-dependent behaviors in rats.

    PubMed

    Roltsch, Emily A; Baynes, Brittni B; Mayeux, Jacques P; Whitaker, Annie M; Baiamonte, Brandon A; Gilpin, Nicholas W

    2014-04-01

    Humans with stress-related anxiety disorders exhibit increases in arousal and alcohol drinking, as well as altered pain processing. Our lab has developed a predator odor stress model that produces reliable and lasting increases in alcohol drinking. Here, we utilize this predator odor stress model to examine stress-induced increases in arousal, nociceptive processing, and alcohol self-administration by rats, and also to determine the effects of corticotropin-releasing factor-1 receptors (CRF1Rs) in mediating these behavioral changes. In a series of separate experiments, rats were exposed to predator odor stress, then tested over subsequent days for thermal nociception in the Hargreaves test, acoustic startle reactivity, or operant alcohol self-administration. In each experiment, rats were systemically injected with R121919, a CRF1R antagonist, and/or vehicle. Predator odor stress increased thermal nociception (i.e., hyperalgesia) and acoustic startle reactivity. Systemic administration of R121919 reduced thermal nociception and hyperarousal in stressed rats but not unstressed controls, and reduced operant alcohol responding over days. Stressed rats exhibited increased sensitivity to the behavioral effects of R121919 in all three tests, suggesting up-regulation of brain CRF1Rs number and/or function in stressed rats. These results suggest that post-stress alcohol drinking may be driven by a high-nociception high-arousal state, and that brain CRF1R signaling mediates these stress effects.

  18. Robust behavioral effects of song playback in the absence of testosterone or corticosterone release.

    PubMed

    Rosvall, Kimberly A; Reichard, Dustin G; Ferguson, Stephen M; Whittaker, Danielle J; Ketterson, Ellen D

    2012-09-01

    Some species of songbirds elevate testosterone in response to territorial intrusions while others do not. The search for a general explanation for this interspecific variation in hormonal response to social challenges has been impeded by methodological differences among studies. We asked whether song playback alone is sufficient to bring about elevation in testosterone or corticosterone in the dark-eyed junco (Junco hyemalis), a species that has previously demonstrated significant testosterone elevation in response to a simulated territorial intrusion when song was accompanied by a live decoy. We studied two populations of juncos that differ in length of breeding season (6-8 vs. 14-16 weeks), and conducted playbacks of high amplitude, long-range song. In one population, we also played low amplitude, short-range song, a highly potent elicitor of aggression in juncos and many songbirds. We observed strong aggressive responses to both types of song, but no detectable elevation of plasma testosterone or corticosterone in either population. We also measured rise in corticosterone in response to handling post-playback, and found full capacity to elevate corticosterone but no effect of song class (long-range or short-range) on elevation. Collectively, our data suggest that males can mount an aggressive response to playback without a change in testosterone or corticosterone, despite the ability to alter these hormones during other types of social interactions. We discuss the observed decoupling of circulating hormones and aggression in relation to mechanisms of behavior and the cues that may activate the HPA and HPG axes.

  19. Suspended nanoparticles in surfactant media as a microextraction technique for simultaneous separation and preconcentration of cobalt, nickel and copper ions for electrothermal atomic absorption spectrometry determination.

    PubMed

    Dadfarnia, Shayessteh; Shakerian, Farid; Shabani, Ali Mohammad Haji

    2013-03-15

    The aim of this study was to describe a new method of microextraction based on the suspension of alumina nanoparticles in the surfactant media for simultaneous separation and preconcentration of the ultra-traces of cobalt, nickel and copper ions. In this technique, the alumina nanoparticles were suspended in the non-ionic surfactant solution of Triton X-114. The analytes in the sample solution were adsorbed onto the nanoparticles. After the phase separation based on the cloud point of the mixture at 40 °C, the nanoparticles settled down in the surfactant rich phase. Then 120 μL of nitric acid (3.0 mol L(-1)) was added to the surfactant rich phase which caused desorption of the analytes. Finally, the liquid phase was separated by centrifugation from the nanoparticles and was used for the quantification of the analytes by the electrothermal atomic absorption spectrometry (ETAAS). The parameters affecting the extraction and detection processes were optimized. Under the optimized experimental conditions (i.e. pH∼8, Triton X-114, 0.05% (v/v); temperature 40 °C), a sample volume of 25 mL resulted in the enhancement factors of 198, 205 and 206 and detection limits (defined as 3Sb/m) of 2.5, 2.8 and 2.6 ng L(-1) for Co(II), Ni(II) and Cu(II) respectively. The sorbent showed high capacity for these metal ions (30-40 mg g(-1) sorbent). The method was successfully applied to the determination of the analytes in natural water samples.

  20. Preparation of a manganese dioxide/carbon fiber electrode for electrosorptive removal of copper ions from water.

    PubMed

    Hu, Chengzhi; Liu, Fangyuan; Lan, Huachun; Liu, Huijuan; Qu, Jiuhui

    2015-05-15

    MnO2 is an effective adsorbent for many metal ions and a promising electrode material for electrochemical supercapacitors. In this paper, we successfully combined the two functions through preparing a MnO2/carbon fiber (CF) composite as an electrosorptive electrode. The thin MnO2 film was deposited onto CF by an anodic eletrodeposition method. The MnO2/CF electrodes had ideal pseudocapacitive behavior and high capacitive reversibility. The specific capacitance of the MnO2/CF electrode reached a maximum value of 387 F/g, which is quite competitive compared with literature values. At 0.8 V applied potential, the maximum Cu(2+) adsorption capacity of the MnO2/CF electrode was 172.88 mg/g, which is more than 2 times higher than common MnO2 adsorbents without an electric field imposed. SEM images showed that MnO2 nanoflowers with several "petals" were uniformly distributed on the CF surface. Enhancement of adsorption by the polarization potential and the unique microstructure of the deposited MnO2 may be the source of the outstanding adsorption ability of the MnO2/CF electrode. The MnO2/CF electrode could be regenerated quickly by reversing the voltage. The deposition time of 1000 s was optimum for achieving maximum capacitance and Cu(2+) removal performance. The MnO2/CF composite electrosorptive electrode is a promising candidate for Cu(2+) removal from aqueous solution.

  1. Nickel release behavior and surface characteristics of porous NiTi shape memory alloy modified by different chemical processes.

    PubMed

    Wu, Shuilin; Liu, Xiangmei; Chan, Y L; Chu, Paul K; Chung, C Y; Chu, Chenglin; Yeung, Kelvin W K; Lu, W W; Cheung, Kenneth M C; Luk, K D K

    2009-05-01

    As a non-line-of-sight surface modification technique, chemical treatment is an effective method to treat porous NiTi with complex surface morphologies and large exposed areas due to its liquidity and low temperature. In the work described here, three different chemical processes are used to treat porous NiTi alloys. Our results show that H(2)O(2) treatment, NaOH treatment, and H(2)O(2) pre-treatment plus subsequent NaOH treatment can mitigate leaching of nickel from the alloy. The porous NiTi samples modified by the two latter processes favor deposition of a layer composed of Ca and P due to the formation of bioactive Na(2)TiO(3) on the surface. Among the three processes, H(2)O(2) pre-treatment plus subsequent NaOH modification is the most effective in suppressing nickel release. Small area X-ray photoelectron spectroscopy reveals that the surfaces treated by different chemical processes have different structures and compositions. The sample modified by the H(2)O(2) treatment is composed of rough TiO(2) on the outer surface and an oxide transition layer underneath whereas the sample treated by NaOH comprises a surface layer of titanium oxide and Na(2)TiO(3) together with a transition layer. The sample processed by the H(2)O(2) and NaOH treatment has a pure Na(2)TiO(3) layer on the surface and a transition layer underneath. These results help to elucidate the different nickel release behavior and bioactivity of porous NiTi alloys processed by different methods.

  2. Chronic Anabolic Androgenic Steroid Exposure Alters Corticotropin Releasing Factor Expression and Anxiety-Like Behaviors in the Female Mouse

    PubMed Central

    Costine, Beth A; Oberlander, Joseph G; Davis, Matthew C; Penatti, Carlos A A; Porter, Donna M; Leaton, Robert N; Henderson, Leslie P

    2010-01-01

    Summary In the past several decades, the therapeutic use of anabolic androgenic steroids (AAS) has been overshadowed by illicit use of these drugs by elite athletes and a growing number of adolescents to enhance performance and body image. As with adults, AAS use by adolescents is associated with a range of behavioral effects, including increased anxiety and altered responses to stress. It has been suggested that adolescents, especially adolescent females, may be particularly susceptible to the effects of these steroids, but few experiments in animal models have been performed to test this assertion. Here we show that chronic exposure of adolescent female mice to a mixture of three commonly abused AAS (testosterone cypionate, nandrolone decanoate and methandrostenolone; 7.5 mg/kg/day for 5 days) significantly enhanced anxiety-like behavior as assessed by the acoustic startle response (ASR), but did not augment the fear-potentiated startle response (FPS) or alter sensorimotor gating as assessed by prepulse inhibition of the acoustic startle response (PPI). AAS treatment also significantly increased the levels of corticotropin releasing factor (CRF) mRNA and somal-associated CRF immunoreactivity in the central amygdala (CeA), as well as neuropil-associated immunoreactivity in the dorsal aspect of the anterolateral division of the bed nucleus of the stria terminalis (dBnST). AAS treatment did not alter CRF receptor 1 or 2 mRNA in either the CeA or the dBnST; CRF immunoreactivity in the ventral BNST, the paraventricular nucleus (PVN) or the median eminence (ME); or peripheral levels of corticosterone. These results suggest that chronic AAS treatment of adolescent female mice may enhance generalized anxiety, but not sensorimotor gating or learned fear, via a mechanism that involves increased CRF-mediated signaling from CeA neurons projecting to the dBnST. PMID:20537804

  3. Chronic anabolic androgenic steroid exposure alters corticotropin releasing factor expression and anxiety-like behaviors in the female mouse.

    PubMed

    Costine, Beth A; Oberlander, Joseph G; Davis, Matthew C; Penatti, Carlos A A; Porter, Donna M; Leaton, Robert N; Henderson, Leslie P

    2010-11-01

    In the past several decades, the therapeutic use of anabolic androgenic steroids (AAS) has been overshadowed by illicit use of these drugs by elite athletes and a growing number of adolescents to enhance performance and body image. As with adults, AAS use by adolescents is associated with a range of behavioral effects, including increased anxiety and altered responses to stress. It has been suggested that adolescents, especially adolescent females, may be particularly susceptible to the effects of these steroids, but few experiments in animal models have been performed to test this assertion. Here we show that chronic exposure of adolescent female mice to a mixture of three commonly abused AAS (testosterone cypionate, nandrolone decanoate and methandrostenolone; 7.5 mg/kg/day for 5 days) significantly enhanced anxiety-like behavior as assessed by the acoustic startle response (ASR), but did not augment the fear-potentiated startle response (FPS) or alter sensorimotor gating as assessed by prepulse inhibition of the acoustic startle response (PPI). AAS treatment also significantly increased the levels of corticotropin releasing factor (CRF) mRNA and somal-associated CRF immunoreactivity in the central nucleus of the amygdala (CeA), as well as neuropil-associated immunoreactivity in the dorsal aspect of the anterolateral division of the bed nucleus of the stria terminalis (dBnST). AAS treatment did not alter CRF receptor 1 or 2 mRNA in either the CeA or the dBnST; CRF immunoreactivity in the ventral BnST, the paraventricular nucleus (PVN) or the median eminence (ME); or peripheral levels of corticosterone. These results suggest that chronic AAS treatment of adolescent female mice may enhance generalized anxiety, but not sensorimotor gating or learned fear, via a mechanism that involves increased CRF-mediated signaling from CeA neurons projecting to the dBnST.

  4. Randomized Controlled Trial of Osmotic-Release Methylphenidate with Cognitive-Behavioral Therapy in Adolescents with Attention-Deficit/Hyperactivity Disorder and Substance Use Disorders

    ERIC Educational Resources Information Center

    Riggs, Paula D.; Winhusen, Theresa; Davies, Robert D.; Leimberger, Jeffrey D.; Mikulich-Gilbertson, Susan; Klein, Constance; Macdonald, Marilyn; Lohman, Michelle; Bailey, Genie L.; Haynes, Louise; Jaffee, William B.; Haminton, Nancy; Hodgkins, Candace; Whitmore, Elizabeth; Trello-Rishel, Kathlene; Tamm, Leanne; Acosta, Michelle C.; Royer-Malvestuto, Charlotte; Subramaniam, Geetha; Fishman, Marc; Holmes, Beverly W.; Kaye, Mary Elyse; Vargo, Mark A.; Woody, George E.; Nunes, Edward V.; Liu, David

    2011-01-01

    Objective: To evaluate the efficacy and safety of osmotic-release methylphenidate (OROS-MPH) compared with placebo for attention-deficit/hyperactivity disorder (ADHD), and the impact on substance treatment outcomes in adolescents concurrently receiving cognitive-behavioral therapy (CBT) for substance use disorders (SUD). Method: This was a…

  5. Reduced axonal localization of a Caps2 splice variant impairs axonal release of BDNF and causes autistic-like behavior in mice

    PubMed Central

    Sadakata, Tetsushi; Shinoda, Yo; Oka, Megumi; Sekine, Yukiko; Sato, Yumi; Saruta, Chihiro; Miwa, Hideki; Tanaka, Mika; Itohara, Shigeyoshi; Furuichi, Teiichi

    2012-01-01

    Ca2+-dependent activator protein for secretion 2 (CAPS2 or CADPS2) potently promotes the release of brain-derived neurotrophic factor (BDNF). A rare splicing form of CAPS2 with deletion of exon3 (dex3) was identified to be overrepresented in some patients with autism. Here, we generated Caps2-dex3 mice and verified a severe impairment in axonal Caps2-dex3 localization, contributing to a reduction in BDNF release from axons. In addition, circuit connectivity, measured by spine and interneuron density, was diminished globally. The collective effect of reduced axonal BDNF release during development was a striking and selective repertoire of deficits in social- and anxiety-related behaviors. Together, these findings represent a unique mouse model of a molecular mechanism linking BDNF-mediated coordination of brain development to autism-related behaviors and patient genotype. PMID:23213205

  6. Reduced axonal localization of a Caps2 splice variant impairs axonal release of BDNF and causes autistic-like behavior in mice.

    PubMed

    Sadakata, Tetsushi; Shinoda, Yo; Oka, Megumi; Sekine, Yukiko; Sato, Yumi; Saruta, Chihiro; Miwa, Hideki; Tanaka, Mika; Itohara, Shigeyoshi; Furuichi, Teiichi

    2012-12-18

    Ca(2)(+)-dependent activator protein for secretion 2 (CAPS2 or CADPS2) potently promotes the release of brain-derived neurotrophic factor (BDNF). A rare splicing form of CAPS2 with deletion of exon3 (dex3) was identified to be overrepresented in some patients with autism. Here, we generated Caps2-dex3 mice and verified a severe impairment in axonal Caps2-dex3 localization, contributing to a reduction in BDNF release from axons. In addition, circuit connectivity, measured by spine and interneuron density, was diminished globally. The collective effect of reduced axonal BDNF release during development was a striking and selective repertoire of deficits in social- and anxiety-related behaviors. Together, these findings represent a unique mouse model of a molecular mechanism linking BDNF-mediated coordination of brain development to autism-related behaviors and patient genotype.

  7. Behavior of TiO(2) released from Nano-TiO(2)-containing paint and comparison to pristine Nano-TiO(2).

    PubMed

    Al-Kattan, Ahmed; Wichser, Adrian; Zuin, Stefano; Arroyo, Yadira; Golanski, Luana; Ulrich, Andrea; Nowack, Bernd

    2014-06-17

    In the assessment of the fate and effects of engineered nanomaterials (ENM), the current focus is on studying the pristine, unaltered materials. However, ENM are incorporated into products and are released over the whole product life cycle, though mainly during the use and disposal phases. So far, released ENMs have only been characterized to a limited extent and almost nothing is known about the behavior of these materials under natural conditions. In this work we obtained material that was released from aged paint containing nano-TiO2, characterized the particulate materials, and studied their colloidal stability in media with different pH and ionic composition. A stable suspension was obtained from aged paint powder by gentle shaking in water, producing a dilute suspension of 580 μg/L TiO2 with an average particle size of 200-300 nm. Most particles in this suspension were small pieces of paint matrix that also contained nano-TiO2. Some free nano-TiO2 particles were observed by electron microscopy, but the majority was enclosed by the organic paint binder. The pristine nano-TiO2 showed the expected colloidal behavior with increasing stability with increasing pH and strong agglomeration above the isoelectric point and settling in the presence of Ca. The released TiO2 showed very small variations in particle size, ζ potential, and colloidal stability, even in the presence of 3 mM Ca. The results show that the behavior of released ENM may not necessarily be predicted by studying the pristine materials. Additionally, effect studies need to focus more on the particles that are actually released as we can expect that the toxic effect will also be markedly different between pristine and product released materials.

  8. Escherichia coli behavior in the presence of organic matter released by algae exposed to water treatment chemicals.

    PubMed

    Bouteleux, C; Saby, S; Tozza, D; Cavard, J; Lahoussine, V; Hartemann, P; Mathieu, L

    2005-02-01

    When exposed to oxidation, algae release dissolved organic matter with significant carbohydrate (52%) and biodegradable (55 to 74%) fractions. This study examined whether algal organic matter (AOM) added in drinking water can compromise water biological stability by supporting bacterial survival. Escherichia coli (1.3 x 10(5) cells ml(-1)) was inoculated in sterile dechlorinated tap water supplemented with various qualities of organic substrate, such as the organic matter coming from chlorinated algae, ozonated algae, and acetate (model molecule) to add 0.2 +/- 0.1 mg of biodegradable dissolved organic carbon (BDOC) liter(-1). Despite equivalent levels of BDOC, E. coli behavior depended on the source of the added organic matter. The addition of AOM from chlorinated algae led to an E. coli growth equivalent to that in nonsupplemented tap water; the addition of AOM from ozonated algae allowed a 4- to 12-fold increase in E. coli proliferation compared to nonsupplemented tap water. Under our experimental conditions, 0.1 mg of algal BDOC was sufficient to support E. coli growth, whereas the 0.7 mg of BDOC liter(-1) initially present in drinking water and an additional 0.2 mg of BDOC acetate liter(-1) were not sufficient. Better maintenance of E. coli cultivability was also observed when AOM was added; cultivability was even increased after addition of AOM from ozonated algae. AOM, likely to be present in treatment plants during algal blooms, and thus potentially in the treated water may compromise water biological stability.

  9. Behavioral measures of cochlear compression and temporal resolution as predictors of speech masking release in hearing-impaired listeners.

    PubMed

    Gregan, Melanie J; Nelson, Peggy B; Oxenham, Andrew J

    2013-10-01

    Hearing-impaired (HI) listeners often show less masking release (MR) than normal-hearing listeners when temporal fluctuations are imposed on a steady-state masker, even when accounting for overall audibility differences. This difference may be related to a loss of cochlear compression in HI listeners. Behavioral estimates of compression, using temporal masking curves (TMCs), were compared with MR for band-limited (500-4000 Hz) speech and pure tones in HI listeners and age-matched, noise-masked normal-hearing (NMNH) listeners. Compression and pure-tone MR estimates were made at 500, 1500, and 4000 Hz. The amount of MR was defined as the difference in performance between steady-state and 10-Hz square-wave-gated speech-shaped noise. In addition, temporal resolution was estimated from the slope of the off-frequency TMC. No significant relationship was found between estimated cochlear compression and MR for either speech or pure tones. NMNH listeners had significantly steeper off-frequency temporal masking recovery slopes than did HI listeners, and a small but significant correlation was observed between poorer temporal resolution and reduced MR for speech. The results suggest either that the effects of hearing impairment on MR are not determined primarily by changes in peripheral compression, or that the TMC does not provide a sufficiently reliable measure of cochlear compression.

  10. Sedative action of cholecystokinin octapeptide on behavioral excitation by thyrotropin releasing hormone and methamphetamine in the rat.

    PubMed

    Katsuura, G; Itoh, S

    1982-01-01

    Intracerebroventricular (i.c.v.) injection of C-terminal octapeptide of cholecystokinin (CCK-8) in rats prolonged pentobarbital- and ethanol-induced sleeping time, but non-sulfated CCD-8 (CCK-8-NS) had no effect and caerulein showed a tendency to prolong the pentobarbital narcosis. On the other hand, i.c.v. injection of thyrotropin releasing hormone (TRH) shortened the sleeping time and the effect of CCK-8 was apparently antagonized by combined administration of TRH. Spontaneous locomotor activity in the late morning and early afternoon was not affected by CCK-8, but it increased following i.c.v. injection of CCK-8-NS. Hyperactivity produced by TRH and methamphetamine was suppressed by i.c.v. injection of CCK-8, while CCK-8-NS showed a tendency to enhance the methamphetamine-induced hyperactivity and caerulein had no effect. These results indicate that CCK-8 has a sedative action and antagonizes the behavioral excitation caused by TRH and methamphetamine, but that the effects of CCK-8-NS and caerulein were rather the opposite of those of CCK-8. In an additional experiment the TRH-induced body shaking response was not affected by combined administration of CCK-8.

  11. Single-Pass Flow-Through Test Elucidation of Weathering Behavior and Evaluation of Contaminant Release Models for Hanford Tank Residual Radioactive Waste

    SciTech Connect

    Cantrell, Kirk J.; Carroll, Kenneth C.; Buck, Edgar C.; Neiner, Doinita; Geiszler, Keith N.

    2013-01-01

    Contaminant release models are required to evaluate and predict long-term environmental impacts of even residual amounts of high-level radioactive waste after cleanup and closure of radioactively contaminated sites such as the DOE’s Hanford Site. More realistic and representative models have been developed for release of uranium, technetium, and chromium from Hanford Site tanks C-202, C-203, and C-103 residual wastes using data collected with a single-pass flow-through test (SPFT) method. These revised models indicate that contaminant release concentrations from these residual wastes will be considerably lower than previous estimates based on batch experiments. For uranium, a thermodynamic solubility model provides an effective description of uranium release, which can account for differences in pore fluid chemistry contacting the waste that could occur through time and as a result of different closure scenarios. Under certain circumstances in the SPFT experiments various calcium rich precipitates (calcium phosphates and calcite) form on the surfaces of the waste particles, inhibiting dissolution of the underlying uranium phases in the waste. This behavior was not observed in previous batch experiments. For both technetium and chromium, empirical release models were developed. In the case of technetium, release from all three wastes was modeled using an equilibrium Kd model. For chromium release, a constant concentration model was applied for all three wastes.

  12. Central administration of growth hormone-releasing hormone triggers downstream movement and schooling behavior of chum salmon (Oncorhynchus keta) fry in an artificial stream.

    PubMed

    Ojima, Daisuke; Iwata, Munehico

    2009-03-01

    Anadromous salmonids migrate downstream to the ocean (downstream migration). The neuroendocrine mechanism of triggering the onset of downstream migration is not well known. We investigated the effects of 14 chemicals, including neuropeptides, pineal hormones, neurotransmitters, and neuromodulators (growth hormone-releasing hormone: GHRH, thyrotropin-releasing hormone, corticotropin-releasing hormone: CRH, gonadotropin-releasing hormone, melatonin, N-acetyl serotonin, serotonin, beta-endorphin, enkephalin, dopamine, norepinephrine, epinephrine, acetylcholine, and histamine) on the onset of downstream migration in chum salmon (Oncorhynchus keta) fry. We defined downstream migration as a downstream movement (negative rheotaxis) with schooling behavior and counted the number of downstream movements and school size in experimental circulation tanks. An intracerebroventricular injection of GHRH, CRH, melatonin, N-acetyl serotonin, or serotonin stimulated the number of downstream movements. However, GHRH was the only chemical that also stimulated an increase in schooling behavior. These results suggest that CRH, melatonin, N-acetyl serotonin, and serotonin are involved in the stimulation of downstream movement in chum salmon, while GHRH stimulates both downstream movement and schooling behavior.

  13. A sensitive and selective sensing platform based on CdTe QDs in the presence of l-cysteine for detection of silver, mercury and copper ions in water and various drinks.

    PubMed

    Gong, Tingting; Liu, Junfeng; Liu, Xinxin; Liu, Jie; Xiang, Jinkun; Wu, Yiwei

    2016-12-15

    Water soluble CdTe quantum dots (QDs) have been prepared simply by one-pot method using potassium tellurite as stable tellurium source and thioglycolic acid (TGA) as stabilizer. The fluorescence of CdTe QDs can be improved 1.3-fold in the presence of l-cysteine (Cys), however, highly efficiently quenched in the presence of silver or mercury or copper ions. A sensitive and selective sensing platform for analysis of silver, mercury and copper ions has been simply established based on CdTe QDs in the presence of l-cysteine. Under the optimum conditions, excellent linear relationships exist between the quenching degree of the sensing platform and the concentrations of Ag(+), Hg(2+) and Cu(2+) ranging from 0.5 to 40ngmL(-1). By using masking agents of sodium diethyldithiocarbamate (DDTC) for Ag(+) and Cu(2+), NH4OH for Ag(+) and Hg(2+) and 1-(2-Pyridylazo)-2-naphthol (PAN) for Hg(2+) and Cu(2+), Hg(2+), Cu(2+) and Ag(+) can be exclusively detected in coexistence with other two ions, and the detection limits (3σ) were 0.65, 0.063 and 0.088ngmL(-1) for Ag(+), Hg(2+) and Cu(2+), respectively. This effective sensing platform has been used to detection of Ag(+), Hg(2+) and Cu(2+) in water and various drinks with satisfactory results.

  14. A role for glucocorticoid-signaling in depression-like behavior of gastrin-releasing peptide receptor knock-out mice.

    PubMed

    Monje, Francisco J; Kim, Eun-Jung; Cabatic, Maureen; Lubec, Gert; Herkner, Kurt R; Pollak, Daniela D

    2011-08-01

    Abstract Background. The gastrin-releasing peptide receptor (GRPR) is highly expressed in the limbic system, where it importantly regulates emotional functions and in the suprachiasmatic nucleus, where it is central for the photic resetting of the circadian clock. Mice lacking GRPR presented with deficient light-induced phase shift in activity as well altered emotional learning and amygdala function. The effect of GRPR deletion on depression-like behavior and its molecular signature in the amygdala, however, has not yet been evaluated. Methods. GRPR knock-out mice (GRPR-KO) were tested in the forced-swim test and the sucrose preference test for depression-like behavior. Gene expression in the basolateral nucleus of the amygdala was evaluated by micorarray analysis subsequent to laser-capture microdissection-assisted extraction of mRNA. The expression of selected genes was confirmed by RT-PCR. Results. GRPR-KO mice were found to present with increased depression-like behavior. Microarray analysis revealed down-regulation of several glucocorticoid-responsive genes in the basolateral amygdala. Acute administration of dexamethasone reversed the behavioral phenotype and alterations in gene expression. Discussion. We propose that deletion of GRPR leads to the induction of depression-like behavior which is paralleled by dysregulation of amygdala gene expression, potentially resulting from deficient light-induced corticosterone release in GRPR-KO.

  15. Regulation of biphasic drug release behavior by graphene oxide in polyvinyl pyrrolidone/poly(ε-caprolactone) core/sheath nanofiber mats.

    PubMed

    Yu, Hui; Yang, Peng; Jia, Yongtang; Zhang, Yumei; Ye, Qiuying; Zeng, Simin

    2016-10-01

    One of the key issues for drug delivery systems is to develop a drug carrier with a time-programmed, biphasic release behavior. Using vancomycin hydrochloride (VAN) as a model drug, polyvinyl pyrrolidone (PVP) blended with graphene oxide (GO) sheets as the core matrix, and poly(ε-caprolactone) (PCL) as the sheath polymer, core/sheath PVP/PCL nanofiber mats were fabricated via a coaxial electrospinning process. We hypothesized that the addition of GO sheets would lead to their molecular interactions with VAN molecules, thereby adjusting the VAN release behavior. Field emission scanning electron microscopy and transmission electron microscopy of the fiber mats revealed their nanofibrous structure and clear core/sheath boundary. Raman analysis demonstrated the presence of GO sheets in the PVP/PCL nanofiber mats. Fourier transform infrared spectroscopy indicated the formation of hydrogen bonds between GO sheets and VAN molecules. In vitro studies showed that the PVP/PCL nanofiber mats were biocompatible, despite the addition of GO sheets, and exhibited typical biphasic drug release profiles, which were tailored by adjusting the content of GO sheets. Furthermore, an antimicrobial test showed different antimicrobial activities of the medicated nanofiber mats, depending on the GO content. Collectively, the results of the present study provide a simple approach to obtaining time-programmed drug release profiles.

  16. Differential dopamine release dynamics in the nucleus accumbens core and shell track distinct aspects of goal-directed behavior for sucrose.

    PubMed

    Cacciapaglia, Fabio; Saddoris, Michael P; Wightman, R Mark; Carelli, Regina M

    2012-04-01

    Mesolimbic dopamine projections to the nucleus accumbens (NAc) have been implicated in goal-directed behaviors for natural rewards and in learning processes involving cue-reward associations. The NAc has been traditionally subdivided into two anatomically distinct sub-regions with different functional properties: the shell and the core. The aim of the present study was to characterize rapid dopamine transmission across the two NAc sub-regions during cue-signaled operant behavior for a natural (sucrose) reward in rats. Using fast-scan cyclic voltammetry (FSCV) we observed differences in the magnitude and dynamics of dopamine release events between the shell and core. Specifically, although cue-evoked dopamine release was observed in both sub-regions, it was larger and longer lasting in the shell compared with the core. Further, secondary dopamine release events were observed following the lever press response for sucrose in the NAc shell, but not the core. These findings demonstrate that the NAc displays regional specificity in dopamine transmission patterns during cued operant behavior for natural reward.

  17. Ionotropic Cross-linked Carbo-protein Micro Matrix System: An Approach for Improvement of Drug Release, Compaction and Tableting behavior of Losartan Potassium.

    PubMed

    Khandai, Madhusmruti; Chakraborty, Santanu; Ghosh, Ashoke Kumar

    2015-01-01

    The aim of the present research work is to develop carbo-protein polymeric complex based sustain release microspheres of losartan potassium and investigate the ability of this dosage form to improve the flowability, compressibility and tableting properties of losartan potassium. The influence of silk sericin, alginate and its blend on various physicochemical parameters and in vitro drug release pattern were studied to optimize the concentration of polymeric blend required for 12 h. sustain release. Optimized batch was subjected to different flowability, compressibility and tableting properties studies to observe the effects of carbo-protein microspheres on flow properties. Results indicated that the concentration of sericin was found to be the main influential factor for prolonged drug release. Different micromeritic studies revealed that the poor flowability and compressibility properties of pure losartan potassium were significantly improved by this algino-sericin microspheric dosage form. Research findings also revealed that plasticity, die filling behavior and tableting properties of the pure drug were significantly improved by this microsphere formulation. So these prospective results concluded that carbo-protein polymeric microspheres helps to sustain the drug release for prolong hours as well as improve the flowability, compressibility and tableting properties of losartan potassium.

  18. The effect of rheological behavior and microstructure of the emulgels on the release and permeation profiles of Terpinen-4-ol.

    PubMed

    Dong, Lina; Liu, Chao; Cun, Dongmei; Fang, Liang

    2015-10-12

    Terpinen-4-ol, the main component of Australian tea tree oil, which was widely used in pharmaceutical and cosmetic fields, was chosen as the active component in this study because of its excellent antimicrobial properties and good permeability. The objective of this study was to investigate the relationships between rheological characters, in vitro release and permeation profiles of the emulgels. Particle size distribution, optical microscopy tests were performed to characterize the status of the emulgels. Scanning electron microscopy and rheology tests were carried out to assess the strength of the structures. In vitro release and percutaneous permeation study of Terpinen-4-ol through Cellophane® membrane and excised rabbit skin were conducted by vertical Franz diffusion cell, respectively. All of the emulgel samples showed a non-uniform bimodal distribution and the microstructure represented a matrix type which could inhibit the diffusion of oil droplets in formulation in some extent. Rheological data showed a good fit to the Herschel-Bulkley model in viscosimetric studies regardless of the polymers used. Moreover, 10% Sepiplus 400 had obtained the highest zero-shear viscosity, G', G″ value and lowest τ95%G' value corresponding to the strongest structure. The results of in vitro release tests revealed that an increase in viscosity may affect the release profiles inversely, irrespective of the polymers used. In vitro permeation of Terpinen-4-ol tests indicated that when the drug amount released could satisfy the essential driving force, permeation processes was independent of release. In contrast, the drug amount released could not satisfy the essential driving force, the permeation amount was inversely proportional to the viscosity as the release amount did.

  19. A longitudinal, qualitative analysis of the context of substance use and sexual behavior among 18- to 29-year-old men after their release from prison.

    PubMed

    Seal, D W; Eldrige, G D; Kacanek, D; Binson, D; Macgowan, R J

    2007-12-01

    Substance use, sexual behavior, and reincarceration among 89 men from 5 state prisons across the USA, aged 18-29 years, were examined in relation to individual patterns of coping with community reintegration after their release from prison. Analyses of a series of qualitative interviews conducted over a 6-month period post-release revealed three global reintegration coping patterns: moving toward successful reintegration, resuming behavioral patterns that preceded incarceration, and reintegrating through withdrawal or isolation. Four key contextual factors that differentiated these three coping patterns were the consistency and extensiveness of social relationships, the nature of social support, and the degree of structural stability (e.g., stable employment and housing). Participants were assigned a Likert scale score (1 for poor rating to 3 for better rating) for their pattern of global reintegration and for their rating on each of the four contextual factors across the longitudinal qualitative interviews. Collectively, these five factors differentiated the prevalence and frequency of substance use, patterns of sexual behavior, and incidence of reincarceration as assessed by a quantitative survey administered 6 months post-release. Poorer ratings on all five contextual indices were related to the use of substances other than marijuana and alcohol. Men with less consistent social relationships reported more sexual partners. However, vaginal or anal sex without a condom was associated with greater social consistency and greater structural stability, possibly due to the presence of a steady main partner. Reincarceration was significantly associated with poorer global reintegration ratings, more negative social support, and less structural stability. These findings highlight the need to consider the role of social and structural support systems in HIV and sexually transmitted infection risk reduction interventions for men after their release from prison.

  20. Activation of spinal group I metabotropic glutamate receptors in rats evokes local glutamate release and spontaneous nociceptive behaviors: effects of 2-methyl-6-(phenylethynyl)-pyridine pretreatment.

    PubMed

    Lorrain, Daniel S; Correa, Lucia; Anderson, Jeffery; Varney, Mark

    2002-07-26

    Intrathecal (i.t.) administration of the group I metabotropic glutamate receptor (mGluR) agonist (RS)-3,5-dihydroxyphenylglycine ((RS)-3,5-DHPG) to rats produces an immediate display of spontaneous nociceptive behaviors (SNBs) persisting for up to 10 h after injection (NeuroReport 7 (1996) 2743). The mechanisms underlying these behavioral effects are not entirely understood but may include enhanced release of glutamate within the dorsal horn of the spinal cord. The current experiments used microdialysis in awake moving animals to test: (1), whether i.t. (S)-3,5-DHPG increases the local release of glutamate at doses that also induce SNBs; and (2), whether the effects on glutamate release (as well as SNBs) can be blocked by pretreatment with the mGluR5 selective antagonist 2-methyl-6-(phenylethynyl)-pyridine (MPEP). Male Sprague-Dawley rats were implanted with a microdialysis probe inserted into the i.t. space of the spinal cord (J. Neurosci. Methods 62 (1995) 43) and then tested under i.t. drug conditions (0.01, 0.1 and 1 mM (S)-3,5-DHPG) following a 2-3 day recovery period. As predicted, local application of (S)-3,5-DHPG via the microdialysis probe increased the release of glutamate in a dose-dependent manner. Significant SNBs were also noted in the 0.1 and 1 mM groups in a manner paralleling the onset and duration of the glutamate response. Pretreatment with MPEP (55 mg/kg, intraperitoneally) blocked glutamate release to the 0.1 mM dose of (S)-3,5-DHPG, and also decreased the proportion of animals displaying SNBs in this dose group. No effects of MPEP were seen against the higher dose of (S)-3,5-DHPG (1 mM). These results suggest that stimulation of spinal mGluR5 leads to glutamate release within the spinal cord, a response that may in part account for the nociceptive behaviors evoked by i.t. (S)-3,5-DHPG.

  1. Comparison of the release behaviors of di (2-ethylhexyl) phthalate and tri(2-ethylhexyl) trimellitate from the polyvinyl-chloride infusion set into pharmaceutical solutions.

    PubMed

    Zhang, Hong; Yang, Fengmin; Shen, Gang; Yang, Yueyang; Tang, Yalin

    2015-05-01

    Polyvinyl-chloride (PVC) with plasticizers of di(2-ethylhexyl) phthalate (DEHP) and tris(2-ethyl- hexyl) trimellitate (TOTM) is widely used in medical and paramedical appliances. However, such plasticizers can leach from PVC products into contact solutions. The aim of this study is to investigate the release behaviors of DEHP and TOTM from the PVC intravenous infusion set into various pharmaceutical solutions under the simulated clinical conditions, such as the lipophilic substances (paclitaxel) , parenteral nutrition (fat emulsion injection) , acid and alkali pharmaceutical solution (levofloxacin hydrochloride injection, pH 3.0-5.0 and furosemide, pH 8.0-9.0). A simple and rapid high-performance liquid chromatographic method with UV detection (HPLC-UV) for the determination of DEHP or TOTM released from PVC medical devices into the above intravenous preparations was developed. The cumulative amounts of DEHP or TOTM released in 24 h were in the same following order: paclitaxel > fat emulsion injection levofloxacin hydrochloride > furosemide solution. From a comparison of the cumulative amounts of released DEHP and TOTM from the above solutions, we found that the cumulative amount of TOTM is far less than that of DEHP, under the same conditions. The cumulative amount of the DEHP released in 24 h in the paclitaxel solution was 21. 14 mg, while under the same conditions, the cumulative amount of TOTM was only 0. 078 mg. The cumulative amount of DEHP is assumed to be about 270 times that of the released TOTM. Thus TOTM could be a superior alternative to DEHP for use in medical devices because of its potential lower leachability.

  2. Polycaprolactone-Coated 3D Printed Tricalcium Phosphate Scaffolds for Bone Tissue Engineering: In Vitro Alendronate Release Behavior and Local Delivery Effect on In Vivo Osteogenesis

    PubMed Central

    2015-01-01

    The aim of this work was to evaluate the effect of in vitro alendronate (AD) release behavior through polycaprolactone (PCL) coating on in vivo bone formation using PCL-coated 3D printed interconnected porous tricalcium phosphate (TCP) scaffolds. Higher AD and Ca2+ ion release was observed at lower pH (5.0) than that at higher pH (7.4). AD and Ca2+ release, surface morphology, and phase analysis after release indicated a matrix degradation dominated AD release caused by TCP dissolution. PCL coating showed its effectiveness for controlled and sustained AD release. Six different scaffold compositions, namely, (i) TCP (bare TCP), (ii) TCP + AD (AD-coated TCP), (iii) TCP + PCL (PCL-coated TCP), (iv) TCP + PCL + AD, (v) TCP + AD + PCL, and (vi) TCP + AD + PCL + AD were tested in the distal femoral defect of Sprague–Dawley rats for 6 and 10 weeks. An excellent bone formation inside the micro and macro pores of the scaffolds was observed from histomorphology. Histomorphometric analysis revealed maximum new bone formation in TCP + AD + PCL scaffolds after 6 weeks. No adverse effect of PCL on bioactivity of TCP and in vivo bone formation was observed. All scaffolds with AD showed higher bone formation and reduced TRAP (tartrate resistant acid phosphatase) positive cells activity compared to bare TCP and TCP coated with only PCL. Bare TCP scaffolds showed the highest TRAP positive cells activity followed by TCP + PCL scaffolds, whereas TCP + AD scaffolds showed the lowest TRAP activity. A higher TRAP positive cells activity was observed in TCP + AD + PCL compared to TCP + AD scaffolds after 6 weeks. Our results show that in vivo local AD delivery from PCL-coated 3DP TCP scaffolds could further induce increased early bone formation. PMID:24826838

  3. Mechanical properties and drug release behavior of PCL/zein coated 45S5 bioactive glass scaffolds for bone tissue engineering application.

    PubMed

    Fereshteh, Zeinab; Nooeaid, Patcharakamon; Fathi, Mohammadhossein; Bagri, Akbar; Boccaccini, Aldo R

    2015-09-01

    This article presents data related to the research article entitled "The effect of coating type on mechanical properties and controlled drug release of PCL/zein coated 45S5 bioactive glass scaffolds for bone tissue engineering" [1]. We provide data on mechanical properties, in vitro bioactivity and drug release of bioactive glass (BG) scaffolds coated by poly (ε-caprolactone) (PCL) and zein used as a controlled release device for tetracycline hydrochloride (TCH). By coating the BG scaffolds with PCL or PCL/zein blend the mechanical properties of the scaffolds were substantially improved, i.e., the compressive strength increased from 0.004±0.001 MPa (uncoated BG scaffolds) to 0.15±0.02 MPa (PCL/zein coated BG scaffolds). A dense bone-like apatite layer formed on the surface of PCL/zein coated scaffolds immersed for 14 days in simulated body fluid (SBF). The data describe control of drug release and in vitro degradation behavior of coating by engineering the concentration of zein. Thus, the developed scaffolds exhibit attractive properties for application in bone tissue engineering research.

  4. Mechanical properties and drug release behavior of PCL/zein coated 45S5 bioactive glass scaffolds for bone tissue engineering application

    PubMed Central

    Fereshteh, Zeinab; Nooeaid, Patcharakamon; Fathi, Mohammadhossein; Bagri, Akbar; Boccaccini, Aldo R.

    2015-01-01

    This article presents data related to the research article entitled “The effect of coating type on mechanical properties and controlled drug release of PCL/zein coated 45S5 bioactive glass scaffolds for bone tissue engineering” [1]. We provide data on mechanical properties, in vitro bioactivity and drug release of bioactive glass (BG) scaffolds coated by poly (ε-caprolactone) (PCL) and zein used as a controlled release device for tetracycline hydrochloride (TCH). By coating the BG scaffolds with PCL or PCL/zein blend the mechanical properties of the scaffolds were substantially improved, i.e., the compressive strength increased from 0.004±0.001 MPa (uncoated BG scaffolds) to 0.15±0.02 MPa (PCL/zein coated BG scaffolds). A dense bone-like apatite layer formed on the surface of PCL/zein coated scaffolds immersed for 14 days in simulated body fluid (SBF). The data describe control of drug release and in vitro degradation behavior of coating by engineering the concentration of zein. Thus, the developed scaffolds exhibit attractive properties for application in bone tissue engineering research. PMID:26966716

  5. Action-potential duration and the modulation of transmitter release from the sensory neurons of Aplysia in presynaptic facilitation and behavioral sensitization.

    PubMed

    Hochner, B; Klein, M; Schacher, S; Kandel, E R

    1986-11-01

    Presynaptic facilitation of transmitter release from Aplysia sensory neurons is an important contributor to behavioral sensitization of the gill and siphon withdrawal reflex. The enhanced release is accompanied by reduction of the serotonin-sensitive S current in the sensory neurons and a consequent increase in duration of the presynaptic action potential (ranging from 10% to 30%). We find that changes of similar magnitude in the duration of depolarizing voltage-clamp steps in sensory neurons in intact abdominal ganglia yield increases in synaptic potentials of 45-120%. In dissociated cell culture, these changes lead to increases of 25-60% in the synaptic potential. Prolongation of presynaptic depolarization using voltage clamp or prolongation of the duration of the action potential by K(+)-channel blockers leads to prolongation of the time-to-peak of the synaptic potentials; similar changes in time-to-peak occur during presynaptic facilitation. The time-to-peak is not changed by homosynaptic depression or by changing the Ca(2+) concentration, procedures that alter release without changing the duration of the action potential. Preventing the spike from broadening by voltage clamping the presynaptic neuron substantially reduces or blocks the facilitation. These results suggest that broadening of the action potential during facilitation is a causal factor in the enhancement of transmitter release.

  6. Characterization of commercial inactive dry yeast preparations for enological use based on their ability to release soluble compounds and their behavior toward aroma compounds in model wines.

    PubMed

    Pozo-Bayón, Maria Angeles; Andujar-Ortiz, Inmaculada; Alcaide-Hidalgo, Juan María; Martín-Alvarez, Pedro J; Moreno-Arribas, M Victoria

    2009-11-25

    The characterization of commercial enological inactive dry yeast (IDY) with different applications in wine production has been carried out. This study was based on the yeast's ability to release soluble compounds (high molecular weight nitrogen, free amino nitrogen, peptidic nitrogen, free amino acids, and polysaccharides) into model wines and on its behavior toward the volatility of seven wine aroma compounds. Important differences in soluble compounds released into the model wines supplemented with commercial IDY were found, with the free amino acids being among the most released. The volatility of most of the aroma compounds was affected by the addition of IDY preparations at a concentration usually employed during winemaking. The extent of this effect was dependent on the physicochemical characteristics of the aroma compound and on the length of time the IDY preparations remained in contact with the model wines. Whereas shorter contact times (2, 4, and 6 days) mainly promoted a "salting-out" effect, longer exposure (9 and 13 days) provoked a retention effect, with the consequent reduction of aroma compounds in the headspace. The use of different commercial preparations also promoted different effects toward the aroma compounds that may be at least in part due to differences in their ability to release soluble compounds of yeast origin into the wines.

  7. Relationship between diffusivity of water molecules inside hydrating tablets and their drug release behavior elucidated by magnetic resonance imaging.

    PubMed

    Kikuchi, Shingo; Onuki, Yoshinori; Kuribayashi, Hideto; Takayama, Kozo

    2012-01-01

    We reported previously that sustained release matrix tablets showed zero-order drug release without being affected by pH change. To understand drug release mechanisms more fully, we monitored the swelling and erosion of hydrating tablets using magnetic resonance imaging (MRI). Three different types of tablets comprised of polyion complex-forming materials and a hydroxypropyl methylcellulose (HPMC) were used. Proton density- and diffusion-weighted images of the hydrating tablets were acquired at intervals. Furthermore, apparent self-diffusion coefficient maps were generated from diffusion-weighted imaging to evaluate the state of hydrating tablets. Our findings indicated that water penetration into polyion complex tablets was faster than that into HPMC matrix tablets. In polyion complex tablets, water molecules were dispersed homogeneously and their diffusivity was relatively high, whereas in HPMC matrix tablets, water molecule movement was tightly restricted within the gel. An optimal tablet formulation determined in a previous study had water molecule penetration and diffusivity properties that appeared intermediate to those of polyion complex and HPMC matrix tablets; water molecules were capable of penetrating throughout the tablets and relatively high diffusivity was similar to that in the polyion complex tablet, whereas like the HPMC matrix tablet, it was well swollen. This study succeeded in characterizing the tablet hydration process. MRI provides profound insight into the state of water molecules in hydrating tablets; thus, it is a useful tool for understanding drug release mechanisms at a molecular level.

  8. Formation and Release Behavior of Iron Corrosion Products under the Influence of Bacterial Communities in a Simulated Water Distribution System

    EPA Science Inventory

    Understanding the effects of biofilm on the iron corrosion, iron release and associated corrosion by-products is critical for maintaining the water quality and the integrity of drinking water distribution system (DWDS). In this work, iron corrosion experiments under sterilized a...

  9. Interaction of calcium sulfate with xanthan gum: effect on in vitro bioadhesion and drug release behavior from xanthan gum based buccal discs of buspirone.

    PubMed

    Jaipal, A; Pandey, M M; Abhishek, A; Vinay, S; Charde, S Y

    2013-11-01

    Bioadhesive polymers in buccal drug delivery systems play an important role in delivery of therapeutic drug molecules for local and systemic action. Xanthan gum, a GRAS listed natural polymer was used to design buccal discs of buspirone hydrochloride by direct compression method. Effect of calcium sulfate on bioadhesive and drug release behavior of xanthan gum buccal discs was studied. Varying amount of calcium sulfate (0%, 5%, 10%, 20%, 30%, 40% and 50%, w/w) in combination with xanthan gum was used to prepare buccal bioadhesive discs. Increase in calcium sulfate concentration resulted in faster drug release and decreased the bioadhesive strength of the designed discs. Further, in rheological evaluation it was observed that viscosity of xanthan gum gel reduces with increasing concentration of calcium sulfate. Compatibility of drug with various excipients was assessed using DSC and FTIR techniques.

  10. CORTICOTROPIN-RELEASING-HORMONE RECEPTORS IN THE MEDIAL PREFRONTAL CORTEX REGULATE HYPOTHALAMIC-PITUITARY-ADRENAL ACTIVITY AND ANXIETY-RELATED BEHAVIOR REGARDLESS OF PRIOR STRESS EXPERIENCE

    PubMed Central

    Jaferi, Azra; Bhatnagar, Seema

    2007-01-01

    The hypothalamic-pituitary-adrenal (HPA) axis habituates, or gradually decreases its activity, with repeated exposure to the same stressor. During habituation, the HPA axis likely requires input from cortical and limbic regions involved in processing of cognitive information that is important in coping to stress. Brain regions such as the medial prefrontal cortex (mPFC) are recognized as important in mediating these processes. The mPFC modulates stress-related behavior and some evidence suggests that the mPFC regulates acute and repeated stress-induced HPA responses. Interestingly, corticotropin releasing hormone(CRH)-1 receptors, which integrate neuroendocrine, behavioral and autonomic responses to stress, are localized in the mPFC but have not been specifically examined with respect to HPA regulation. We hypothesized that CRH receptor activity in the mPFC contributes to stress-induced regulation of HPA activity and anxiety-related behavior, and that CRH release in the mPFC may differentially regulate HPA responses in acutely- compared to repeatedly-stressed animals. In the present experiments, we found that blockade of CRH receptors in the mPFC with the non-selective receptor antagonist, D-Phe-CRH (50ng or 100ng) significantly inhibited HPA responses compared to vehicle regardless of whether animals were exposed to a single, acute 30min restraint or to the eighth 30min restraint. We also found that intra-mPFC injections of CRH (20ng) significantly increased anxiety-related behavior in the elevated plus maze in both acutely- and repeatedly-restrained groups compared to vehicle. Together, these results suggest an excitatory influence of CRH in the mPFC on stress-induced HPA activity and anxiety-related behavior regardless of prior stress experience. PMID:18001698

  11. High-Risk Behaviors after Release from Incarceration among People Who Inject Drugs in St. Petersburg, Russia

    PubMed Central

    Cepeda, Javier A.; Niccolai, Linda M.; Lyubimova, Alexandra; Kershaw, Trace; Levina, Olga; Heimer, Robert

    2014-01-01

    Background Injection drug use, infectious disease, and incarceration are inextricably linked in Russia. We aimed to identify factors associated with time to relapse (first opioid injection after release from prison) and using a non-sterile, previously used syringe at relapse in a sample of people who inject drugs in St. Petersburg. Methods We collected data on time from release to relapse among individuals with a history of incarceration, a subsample of a larger study among people who inject drugs. Proportional hazards and logistic regression were used to identify factors associated with time to relapse and injection with a non-sterile previously used syringe at relapse, respectively. Results The median time to relapse after release was 30 days. Factors that were independently associated with relapsing sooner were being a native of St. Petersburg compared to not being native (AHR: 1.64; 95% CI 1.15 – 2.33), unemployed at relapse compared to employed (AHR: 4.49; 95% CI 2.96 – 6.82) and receiving a previous diagnosis of HBV and HCV compared to no previous diagnosis (AHR: 1.49; 95% CI 1.03 – 2.14). Unemployment at relapse was also significant in modeling injection with a non-sterile, previously used syringe at relapse compared to those who were employed (AOR: 6.80; 95% CI 1.96 – 23.59). Conclusions Unemployment was an important correlate for both resuming opioid injection after release and using a non-sterile previously used syringe at relapse. Linkage to medical, harm reduction, and employment services should be developed for incarcerated Russian people who inject drugs prior to release. PMID:25496706

  12. Dynamic changes in extracellular release of GABA and glutamate in the lateral septum during social play behavior in juvenile rats: Implications for sex-specific regulation of social play behavior.

    PubMed

    Bredewold, R; Schiavo, J K; van der Hart, M; Verreij, M; Veenema, A H

    2015-10-29

    Social play is a motivated and rewarding behavior that is displayed by nearly all mammals and peaks in the juvenile period. Moreover, social play is essential for the development of social skills and is impaired in social disorders like autism. We recently showed that the lateral septum (LS) is involved in the regulation of social play behavior in juvenile male and female rats. The LS is largely modulated by GABA and glutamate neurotransmission, but their role in social play behavior is unknown. Here, we determined whether social play behavior is associated with changes in the extracellular release of GABA and glutamate in the LS and to what extent such changes modulate social play behavior in male and female juvenile rats. Using intracerebral microdialysis in freely behaving rats, we found no sex difference in extracellular GABA concentrations, but extracellular glutamate concentrations are higher in males than in females under baseline conditions and during social play. This resulted in a higher glutamate/GABA concentration ratio in males vs. females and thus, an excitatory predominance in the LS of males. Furthermore, social play behavior in both sexes is associated with significant increases in extracellular release of GABA and glutamate in the LS. Pharmacological blockade of GABA-A receptors in the LS with bicuculline (100 ng/0.5 μl, 250 ng/0.5 μl) dose-dependently decreased the duration of social play behavior in both sexes. In contrast, pharmacological blockade of ionotropic glutamate receptors (NMDA and AMPA/kainate receptors) in the LS with AP-5+CNQX (2mM+0.4mM/0.5 μl, 30 mM+3mM/0.5 μl) dose-dependently decreased the duration of social play behavior in females, but did not alter social play behavior in males. Together, these data suggest a role for GABA neurotransmission in the LS in the regulation of juvenile social play behavior in both sexes, while glutamate neurotransmission in the LS is involved in the sex-specific regulation of juvenile social

  13. Controlling the release of active compounds from the inorganic carrier halloysite

    NASA Astrophysics Data System (ADS)

    Tescione, F.; Buonocore, G. G.; Stanzione, M.; Oliviero, M.; Lavorgna, M.

    2014-05-01

    Halloysite (HNTs), a natural material characterized by a nanotube structure, has been used as an inorganic carrier of active compounds in several applications from medicine to anticorrosion coatings. In this present work, vanillin (VAN) used as a antimicrobial model, has been encapsulated within HNTs for exploiting its applicability in the active food packaging sector. The molecule release rate has been controlled by crosslinking at the tube ends the loaded vanillin with copper ions, thus producing a stopper network. The vanillin-loaded HNTs were characterized using transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectroscopy and thermo gravimetric analysis. The antimicrobial release kinetics from the loaded nanoparticles (VAN/HNTs) in water was investigated using UV-vis spectroscopy. The results show that the vanillin crosslinked with cupper ions is a feasible method to tailor the release rate of antimicrobial model from HTNs nanoparticles.

  14. Controlling the release of active compounds from the inorganic carrier halloysite

    SciTech Connect

    Tescione, F.; Buonocore, G. G.; Stanzione, M.; Oliviero, M.; Lavorgna, M.

    2014-05-15

    Halloysite (HNTs), a natural material characterized by a nanotube structure, has been used as an inorganic carrier of active compounds in several applications from medicine to anticorrosion coatings. In this present work, vanillin (VAN) used as a antimicrobial model, has been encapsulated within HNTs for exploiting its applicability in the active food packaging sector. The molecule release rate has been controlled by crosslinking at the tube ends the loaded vanillin with copper ions, thus producing a stopper network. The vanillin-loaded HNTs were characterized using transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectroscopy and thermo gravimetric analysis. The antimicrobial release kinetics from the loaded nanoparticles (VAN/HNTs) in water was investigated using UV-vis spectroscopy. The results show that the vanillin crosslinked with cupper ions is a feasible method to tailor the release rate of antimicrobial model from HTNs nanoparticles.

  15. Virus-mediated release of endosomal content in vitro: different behavior of adenovirus and rhinovirus serotype 2

    PubMed Central

    1995-01-01

    Endosomal penetration by nonenveloped viruses might be accomplished by either local breakdown of the endosomal membrane (e.g., adenovirus) or formation of a membrane-spanning pore by capsid proteins. Uncoating of the nonenveloped virus human rhinovirus serotype 2 (HRV2) has been shown to occur from late endosomes and to be entirely dependent on the acidic pH in this compartment (Prchla, E., E. Kuechler, D. Blaas, and R. Fuchs. 1994. J. Virol. 68: 3713-3723). To investigate further the mechanism of uncoating of HRV2, an in vitro assay was established to test viruses or virus-derived peptides for their capacity to release cointernalized biotin-dextran of different molecular mass (10 and 70 kD) from isolated endosomes. The suitability of the assay was demonstrated by use of a fusogenic peptide derived from influenza virus hemagglutinin (GALA-INF3). Whereas adenovirus induced a low pH- dependent release of up to 46% of the internalized biotin-dextran and did not show any significant size selectivity (as expected for endosome disruption), HRV2 mediated release of 27% of the 10 kD dextran and only traces of the 70-kD dextran. Similarly, GALA-INF3-induced release of biotin-dextran was also size dependent. The potential role of the capsid protein VP1 in HRV2 uncoating in vivo was also substantiated in our in vitro system using an amphipathic, NH2-terminal peptide of VP1. Taken together, these data favor the model of a specific pore-forming mechanism for HRV2 uncoating which is in contrast to the membrane- disrupting mechanism of adenovirus. PMID:7559769

  16. Biocompatibility and drug release behavior of scaffolds prepared by coaxial electrospinning of poly(butylene succinate) and polyethylene glycol.

    PubMed

    Llorens, E; Ibañez, H; Del Valle, L J; Puiggalí, J

    2015-04-01

    Scaffolds constituted by electrospun microfibers of poly(ethylene glycol) (PEG) and poly(butylene succinate) (PBS) were studied. Specifically, coaxial microfibers having different core-shell distributions and compositions were considered as well as uniaxial micro/nanofibers prepared from mixtures of both polymers. Processing conditions were optimized for all geometries and compositions and resulting morphologies (i.e. diameter and surface texture) characterized by scanning electron microscopy. Chemical composition, molecular interactions and thermal properties were evaluated by FTIR, NMR, XPS and differential scanning calorimetry. The PEG component of electrospun fibers could be solubilized by immersion of scaffolds in aqueous medium, giving rise to high porosity and hydrophobic samples. Nevertheless, a small amount of PEG was retained in the PBS matrix, suggesting some degree of mixing. Solubilization was slightly dependent on fiber structure; specifically, the distribution of PEG in the core or shell of coaxial fibers led to higher or lower retention levels, respectively. Scaffolds could be effectively loaded with hydrophobic drugs having antibacterial and anticarcinogenic activities like triclosan and curcumin, respectively. Their release was highly dependent on their chemical structure and medium composition. Thus, low and high release rates were observed in phosphate buffer saline (SS) and SS/ethanol (30:70 v/v), respectively. Slight differences in the release of triclosan were found depending on fiber distribution and composition. Antibacterial activity and biocompatibility were evaluated for both loaded and unloaded scaffolds.

  17. Release behavior of non-network proteins and its relationship to the structure of heat-induced soy protein gels.

    PubMed

    Wu, Chao; Hua, Yufei; Chen, Yeming; Kong, Xiangzhen; Zhang, Caimeng

    2015-04-29

    Heat-induced soy protein gels were prepared by heating protein solutions at 12%, 15% ,or 18% for 0.5, 1.0, or 2.0 h. The release of non-network proteins from gel slices was conducted in 10 mM pH 7.0 sodium phosphate buffer. SDS-PAGE and diagonal electrophoresis demonstrated that the released proteins consisted of undenatured AB subunits and denatured proteins including monomers of A polypeptides, disulfide bond linked dimers, trimers, and polymers of A polypeptides, and an unidentified 15 kDa protein. SEC-HPLC analysis of non-network proteins revealed three major protein peaks, with molecular weights of approximately 253.9, 44.8, and 9.7 kDa. The experimental data showed that the time-dependent release of the three fractions from soy protein gels fit Fick's second law. An increasing protein concentration or heating time resulted in a decrease in diffusion coefficients of non-network proteins. A power law expression was used to describe the relationship between non-network protein diffusion coefficient and molecular weight, for which the exponent (α) shifted to higher value with an increase in protein concentration or heating time, indicating that a more compact gel structure was formed.

  18. Small-scale pig farmers' behavior, silent release of African swine fever virus and consequences for disease spread.

    PubMed

    Costard, Solenne; Zagmutt, Francisco J; Porphyre, Thibaud; Pfeiffer, Dirk Udo

    2015-11-27

    The expanding distribution of African swine fever (ASF) is threatening the pig industry worldwide. Most outbreaks occur in backyard and small-scale herds, where poor farmers often attempt to limit the disease's economic consequences by the emergency sale of their pigs. The risk of African swine fever virus (ASFV) release via this emergency sale was investigated. Simulation modeling was used to study ASFV transmission in backyard and small-scale farms as well as the emergency sale of pigs, and the potential impact of improving farmers and traders' clinical diagnosis ability-its timeliness and/or accuracy-was assessed. The risk of ASFV release was shown to be high, and improving farmers' clinical diagnosis ability does not appear sufficient to effectively reduce this risk. Estimates obtained also showed that the distribution of herd size within the backyard and small-scale sectors influences the relative contribution of these farms to the risk of release of infected pigs. These findings can inform surveillance and control programs.

  19. Pharmacokinetics and Behavioral Effects of an Extended-Release, Liposome-Encapsulated Preparation of Oxymorphone in Rhesus Macaques

    PubMed Central

    Krugner-Higby, Lisa; KuKanich, Butch; Schmidt, Brynn; Heath, Timothy D.; Brown, Carolyn; Smith, Lesley J.

    2009-01-01

    The objectives of the study were to determine the pharmacokinetics of oxymorphone (oxy) and of ammonium sulfate-loaded, liposome-encapsulated oxymorphone (LE-ASG oxy) and to evaluate the behavioral effects of both opioid preparations by using ethographic evaluation specific to rhesus monkeys. Rhesus monkeys (n = 8) were injected with 2.0 mg/kg LE-ASG oxy s.c.. Blood samples were collected at serial time points up to 144 h in six monkeys and up to 456 h in two monkeys. Separate groups of monkeys were injected with 0.1 mg/kg oxy s.c. (n = 4) or i.v. (n = 5). Blood samples were collected at serial time points up to 24 h after injection. Pharmacokinetic parameters were calculated by using commercially available software. Behavior was recorded in a different group of 10 monkeys administered LE-ASG oxy (2.0 mg/kg s.c.) or oxy (0.1 mg/kg s.c.) on separate occasions. Behavioral evaluations were made at serial time points while monkeys were in an extended cage with a compatible stimulus animal. Oxymorphone was rapidly eliminated from the serum in the oxy group. Measurable drug was present in serum for up to 4 h after oxy was administered subcutaneously or intravenously. LE-ASG oxy was present in serum in measurable concentrations for more than 2 weeks. Neither oxy nor LE-ASG oxy produced observable sedation. LE-ASG oxy decreased some environmentally directed behaviors, but this drug formulation increased watchfulness, decreased self-directed and elimination behaviors, increased nonspecific social contact, and decreased threat behaviors. LE-ASG oxy persisted for an extended period in rhesus monkey serum and produced behavioral changes consistent with this opioid. PMID:19351868

  20. High chemical diversity in a wasp pheromone: a blend of methyl 6-methylsalicylate, fatty alcohol acetates and cuticular hydrocarbons releases courtship behavior in the Drosophila parasitoid Asobara tabida.

    PubMed

    Stökl, Johannes; Dandekar, Anna-Teresa; Ruther, Joachim

    2014-02-01

    Wasps of genus Asobara, a larval parasitoid of Drosophila, have become model organisms for the study of host-parasite interactions. However, little is known about the role of pheromones in locating mates and courtship behavior in this genus. In the present study, we aimed to identify the female courtship pheromone in Asobara tabida. The chemical compositions of solvent extracts from male and female wasps were analyzed by GC/MS. These extracts, fractions thereof, and synthetic pheromone candidates were tested for their activity in behavioral bioassays. The results demonstrate that the courtship pheromone of A. tabida is characterized by a remarkable chemical diversity. A multi-component blend of female-specific compounds including methyl 6-methylsalicylate (M6M), fatty alcohol acetates (FAAs), and cuticular hydrocarbons (CHCs) released male courtship behavior. Using a combinatory approach that included both purified natural products and synthetic analogs, it was shown that none of the three chemical classes alone was sufficient to release a full behavioral response in males. However, a blend of M6M and FAAs or combinations of one or both of these with female-derived CHCs resulted in wing-fanning responses by males comparable to those elicited by the crude extract of females. Thus, components from all three chemical classes contribute to the bioactivity of the pheromone, but none of the elements plays a key role or is irreplaceable. The fact that one of the FAAs, vaccenyl acetate, is also used as a kairomone by Asobara females to locate Drosophila hosts suggests that a pre-existing sensory responsiveness to vaccenyl acetate might have been involved in the evolution of the female sex pheromone in Asobara.

  1. Behavior patterns and fates of adult steelhead, Chinook salmon, and coho salmon released into the upper Cowlitz River Basin, 2005–09 and 2012, Washington

    USGS Publications Warehouse

    Kock, Tobias J.; Ekstrom, Brian K.; Liedtke, Theresa L.; Serl, John D.; Kohn, Mike

    2016-08-26

    A multiyear radiotelemetry evaluation was conducted to monitor adult steelhead (Oncorhynchus mykiss), Chinook salmon (O. tshawytscha), and coho salmon (O. kisutch) behavior and movement patterns in the upper Cowlitz River Basin. Volitional passage to this area was eliminated by dam construction in the mid-1960s, and a reintroduction program began in the mid-1990s. Fish are transported around the dams using a trap-and-haul program, and adult release sites are located in Lake Scanewa, the uppermost reservoir in the system, and in the Cowlitz and Cispus Rivers. Our goal was to estimate the proportion of tagged fish that fell back downstream of Cowlitz Falls Dam before the spawning period and to determine the proportion that were present in the Cowlitz and Cispus Rivers during the spawning period. Fallback is important because Cowlitz Falls Dam does not have upstream fish passage, so fish that pass the dam are unable to move back upstream and spawn. A total of 2,051 steelhead and salmon were tagged for the study, which was conducted during 2005–09 and 2012, and 173 (8.4 percent) of these regurgitated their transmitter prior to, or shortly after release. Once these fish were removed from the dataset, the final number of fish that was monitored totaled 1,878 fish, including 647 steelhead, 770 Chinook salmon, and 461 coho salmon.Hatchery-origin (HOR) and natural-origin (NOR) steelhead, Chinook salmon, and coho salmon behaved differently following release into Lake Scanewa. Detection records showed that the percentage of HOR fish that moved upstream and entered the Cowlitz River or Cispus River after release was relatively low (steelhead = 38 percent; Chinook salmon = 67 percent; coho salmon = 41 percent) compared to NOR fish (steelhead = 84 percent; Chinook salmon = 82 percent; coho salmon = 76 percent). The elapsed time from release to river entry was significantly lower for NOR fish than for HOR fish for all three species. Tagged fish entered the Cowlitz River in

  2. Surface Modification of NiTi Alloy via Cathodic Plasma Electrolytic Deposition and its Effect on Ni Ion Release and Osteoblast Behaviors

    NASA Astrophysics Data System (ADS)

    Yan, Ying; Cai, Kaiyong; Yang, Weihu; Liu, Peng

    2013-07-01

    To reduce Ni ion release and improve biocompatibility of NiTi alloy, the cathodic plasma electrolytic deposition (CPED) technique was used to fabricate ceramic coating onto a NiTi alloy surface. The formation of a coating with a rough and micro-textured surface was confirmed by X-ray diffraction, scanning electron microscopy, and energy-dispersive X-ray spectroscopy, respectively. An inductively coupled plasma mass spectrometry test showed that the formed coating significantly reduced the release of Ni ions from the NiTi alloy in simulated body fluid. The influence of CPED treated NiTi substrates on the biological behaviors of osteoblasts, including cell adhesion, cell viability, and osteogenic differentiation function (alkaline phosphatase), was investigated in vitro. Immunofluorescence staining of nuclei revealed that the CPED treated NiTi alloy was favorable for cell growth. Osteoblasts on CPED modified NiTi alloy showed greater cell viability than those for the native NiTi substrate after 4 and 7 days cultures. More importantly, osteoblasts cultured onto a modified NiTi sample displayed significantly higher differentiation levels of alkaline phosphatase. The results suggested that surface functionalization of NiTi alloy with ceramic coating via the CPED technique was beneficial for cell proliferation and differentiation. The approach presented here is useful for NiTi implants to enhance bone osseointegration and reduce Ni ion release in vitro.

  3. Corrosion and ion release behavior of Cu/Ti film prepared via physical vapor deposition in vitro as potential biomaterials for cardiovascular devices

    NASA Astrophysics Data System (ADS)

    Liu, Hengquan; Zhang, Deyuan; Shen, Feng; Zhang, Gui; Song, Shenhua

    2012-07-01

    Cu/Ti films of various Cu/Ti ratios were prepared on a TiNi alloy via vacuum arc plasma deposition. The phase composition, structure, and concentration of elements were investigated via X-ray diffraction and X-photoelectron energy spectrum. The hemolysis ratio and platelet adhesion of the different films were characterized to evaluate blood compatibility. The corrosion and ion release behavior were investigated via a typical immersion test and electrochemical method. The growth of endothelial cells (ECs) was investigated, and methylthiazolyte-trazolium method was employed to evaluate the effect of Cu2+. The sophisticated films showed good compatibility. However, with increasing quality ratio of Cu/Ti, the hemolysis ratio increased, and some platelets started to break slightly. The Cu2+ release was gradually stabilized. The open circuit potential of the Cu/Ti film-modified samples was lower than that of the TiNi substrate. The polarization test result indicates that the passivation stability performance of Cu/Ti film samples is less than the TiNi substrate, and is favorable to Cu2+ release. The adhesion and proliferation of ECs would be inhibited with 10 wt.% Cu concentration of the film, and ECs would undergo apoptosis at >50 wt.% concentration. A Cu/Ti film with good compatibility and anti-endothelialization has potential applications for special cardiovascular devices.

  4. Influence of sodium dodecyl sulfate on swelling, erosion and release behavior of HPMC matrix tablets containing a poorly water-soluble drug.

    PubMed

    Zeng, Aiguo; Yuan, Bingxiang; Fu, Qiang; Wang, Changhe; Zhao, Guilan

    2009-01-01

    The effect of sodium dodecyl sulfate (SDS) on the swelling, erosion and release behavior of HPMC matrix tablets was examined. Swelling and erosion of HPMC matrix tablets were determined by measuring the wet and subsequent dry weights of matrices. The rate of uptake of the dissolution medium by the matrix was quantified using a square root relationship whilst the erosion of the polymer was described using the cube root law. The extent of swelling decreased with increasing SDS concentrations in the dissolution medium but the rate of erosion was found to follow a reverse trend. Such phenomena might have been caused by the attractive hydrophobic interaction between HPMC and SDS as demonstrated by the cloud points of the solutions containing both the surfactant and polymer. Release profiles of nimodipine from HPMC tablets in aqueous media containing different concentrations of SDS were finally studied. Increasing SDS concentrations in the medium was shown to accelerate the release of nimodipine from the tablets, possibly due to increasing nimodipine solubility and increasing rate of erosion by increasing SDS concentrations in the dissolution medium.

  5. Sexual dimorphism of gonadotropin-releasing hormone type-III (GnRH3) neurons and hormonal sex reversal of male reproductive behavior in Mozambique tilapia.

    PubMed

    Kuramochi, Asami; Tsutiya, Atsuhiro; Kaneko, Toyoji; Ohtani-Kaneko, Ritsuko

    2011-10-01

    In tilapia, hormone treatment during the period of sexual differentiation can alter the phenotype of the gonads, indicating that endocrine factors can cause gonadal sex reversal. However, the endocrine mechanism underlying sex reversal of reproductive behaviors remains unsolved. In the present study, we detected sexual dimorphism of gonadotropin-releasing hormone type III (GnRH3) neurons in Mozambique tilapia Oreochromis mossambicus. Our immunohistochemical observations showed sex differences in the number of GnRH3 immunoreactive neurons in mature tilapia; males had a greater number of GnRH3 neurons in the terminal ganglion than females. Treatment with androgen (11-ketotestosterone (11-KT) or methyltestosterone), but not that with 17β-estradiol, increased the number of GnRH3 neurons in females to a level similar to that in males. Furthermore, male-specific nest-building behavior was induced in 70% of females treated with 11-KT within two weeks after the onset of the treatment. These results indicate androgen-dependent regulation of GnRH3 neurons and nest-building behavior, suggesting that GnRH3 is importantly involved in sex reversal of male-specific reproductive behavior.

  6. Effects of their nutrient precursors on the synthesis and release of serotonin, the catecholamines, and acetylcholine - Implications for behavioral disorders

    NASA Technical Reports Server (NTRS)

    Wurtman, Richard J.

    1988-01-01

    Authentic foods affect brain serotonin synthesis by modifying brain tryptophan levels, carbohydrates increasing and proteins decreasing these levels. The carbohydrate-induced rise in brain serotonin tends to diminish the likelihood that one carbohydrate-rich, protein-poor meal or snack will be followed by another. This mechanism is apparently disturbed in carbohydrate-craving obesity, which may explain why this syndrome responds well to d-fenfluramine, a serotoninergic drug. Pure nutrients like tyrosine or choline can also affect the rates at which their neurotransmitter products, the catecholamines and acetylcholine, are synthesized in and released from nerve terminals, suggesting that these compounds may find uses as drugs.

  7. A mark-release-recapture study using a novel portable hut design to define the flight behavior of Anopheles darlingi in Belize, Central America.

    PubMed

    Achee, Nicole L; Grieco, John P; Andre, Richard G; Rejmankova, Eliska; Roberts, Donald R

    2005-12-01

    Knowledge of the flight behavior of local vectors is of paramount importance in mosquito control programs. The following study defined the recapture rate of wild-caught, unengorged Anopheles darlingi females at 0, 400, and 800 m from a fixed release point in Belize, Central America, using a newly designed portable experimental hut. Three sampling trials, each consisting of 2 12-h collections, were performed at all distances from July 2002 to June 2003. A total of 1,185 An. darlingi were marked and released during the course of the study. The recapture rate was greatest at 0 m (29.0%; 124/428) and declined from 11.6% (37/318) at 400 m to 5.8% (21/361) at the 800-m site. There was no difference between the average number of marked mosquitoes recaptured inside the experimental hut versus outside the hut at any distance location. Recapture rates of each trial were highest during the first night's collection at all locations. Further examination of the first night data revealed a variation in the peak time of recapture by distances from the release point. The peak in nightly recapture at both the 0- and 400-m sites occurred within the first 2 h after sunset, and the peak recapture at the 800-m site occurred during the 7th h after sunset. Information from the present study is the first to describe the flight behavior of An. darlingi in Belize and will benefit in the development of adult-density risk assessments at the house level based on distances from potential vector breeding sites.

  8. Resistant starch film-coated microparticles for an oral colon-specific polypeptide delivery system and its release behaviors.

    PubMed

    Situ, Wenbei; Chen, Ling; Wang, Xueyu; Li, Xiaoxi

    2014-04-23

    For the delivery of bioactive components to the colon, an oral colon-specific controlled release system coated with a resistant starch-based film through aqueous dispersion coating process was developed. Starch was modified by a high-temperature-pressure reaction, enzymatic debranching, and retrogradation, resulting in a dramatic increase in the resistibility against enzymatic digestion (meaning the formation of resistant starch, specifically RS3). This increase could be associated with an increase in the relative crystallinity, a greater amount of starch molecular aggregation structure, and the formation of a compact mass fractal structure, resulting from the treatment. The microparticles coated with this RS3 film showed an excellent controlled release property. In streptozotocin (STZ)-induced type II diabetic rats, the RS3 film-coated insulin-loaded microparticles exhibited the ability to steadily decrease the plasma glucose level initially and then maintain the plasma glucose level within the normal range for total 14-22 h with different insulin dosages after oral administration; no glycopenia or glycemic fluctuation was observed. Therefore, the potential of this new RS3 film-coated microparticle system has been demonstrated for the accurate delivery of bioactive polypeptides or protein to the colon.

  9. Effect of cyclodextrins and pH on the permeation of tetracaine: supramolecular assemblies and release behavior.

    PubMed

    Teixeira, Raquel S; Veiga, Francisco J B; Oliveira, Rita S; Jones, Stuart A; Silva, Sérgio M C; Carvalho, Rui A; Valente, Artur J M

    2014-05-15

    This work provides a new insight on fundamental principles of the interaction mechanism between two forms of tetracaine - a potent local anesthetic - both in neutral (TC) and ionized (TC(+)) states, with beta- (β-CD) and hydroxypropyl-beta-cyclodextrin (HP-β-CD), and how such interactions affect the transport of tetracaine, at different concentrations, across a model membrane. The kinetics and mechanism of TC release from HPMC gels is also evaluated giving an insight on the role of cyclodextrin on the tetracaine transport. HPLC, fluorescence and NMR spectroscopies provided solid physicochemical knowledge of these systems and in vitro studies were performed to obtain relevant data on the transport and mechanism parameters. HPLC and fluorescence spectroscopy data revealed that tetracaine interacts with both cyclodextrins on a 1:1 stoichiometry but it is observed that neutral tetracaine forms more stables complexes (ca. 1050 M(-1) for both cyclodextrins) than in its ionized form (628 and 337 M(-1) for β-CD and HP-β-CD respectively). Despite of that, no host-guest interactions take place as seen by ROESY. This study clearly demonstrates that both forms of tetracaine are successfully released from the formulations at a controlled rate, following a Super-Case transport mechanism and the transport of tetracaine can be tuned by using cyclodextrins.

  10. Release behavior and toxicity profiles towards A549 cell lines of ciprofloxacin from its layered zinc hydroxide intercalation compound

    PubMed Central

    2013-01-01

    Background Layered hydroxides salts (LHS), a layered inorganic compound is gaining attention in a wide range of applications, particularly due to its unique anion exchange properties. In this work, layered zinc hydroxide nitrate (LZH), a family member of LHS was intercalated with anionic ciprofloxacin (CFX), a broad spectrum antibiotic via ion exchange in a mixture solution of water:ethanol. Results Powder x-ray diffraction (XRD), Fourier transform infrared (FTIR) and thermogravimetric analysis (TGA) confirmed the drug anions were successfully intercalated in the interlayer space of LZH. Specific surface area of the obtained compound was increased compared to that of the host due to the different pore textures between the two materials. CFX anions were slowly released over 80 hours in phosphate-buffered saline (PBS) solution due to strong interactions that occurred between the intercalated anions and the host lattices. The intercalation compound demonstrated enhanced antiproliferative effects towards A549 cancer cells compared to the toxicity of CFX alone. Conclusions Strong host-guest interactions between the LZH lattice and the CFX anion give rise to a new intercalation compound that demonstrates sustained release mode and enhanced toxicity effects towards A549 cell lines. These findings should serve as foundations towards further developments of the brucite-like host material in drug delivery systems. PMID:23849189

  11. Encapsulation of gallic acid/cyclodextrin inclusion complex in electrospun polylactic acid nanofibers: Release behavior and antioxidant activity of gallic acid.

    PubMed

    Aytac, Zeynep; Kusku, Semran Ipek; Durgun, Engin; Uyar, Tamer

    2016-06-01

    Cyclodextrin-inclusion complexes (CD-ICs) possess great prominence in food and pharmaceutical industries due to their enhanced ability for stabilization of active compounds during processing, storage and usage. Here, CD-IC of gallic acid (GA) with hydroxypropyl-beta-cyclodextrin (GA/HPβCD-IC) was prepared and then incorporated into polylactic acid (PLA) nanofibers (PLA/GA/HPβCD-IC-NF) using electrospinning technique to observe the effect of CD-ICs in the release behavior of GA into three different mediums (water, 10% ethanol and 95% ethanol). The GA incorporated PLA nanofibers (PLA/GA-NFs) were served as control. Phase solubility studies showed an enhanced solubility of GA with increasing amount of HPβCD. The detailed characterization techniques (XRD, TGA and (1)H-NMR) confirmed the formation of inclusion complex between GA and HPβCD. Computational modeling studies indicated that the GA made an efficient complex with HPβCD at 1:1 either in vacuum or aqueous system. SEM images revealed the bead-free and uniform morphology of PLA/GA/HPβCD-IC-NF. The release studies of GA from PLA/GA/HPβCD-IC-NF and PLA/GA-NF were carried out in water, 10% ethanol and 95% ethanol, and the findings revealed that PLA/GA/HPβCD-IC-NF has released much more amount of GA in water and 10% ethanol system when compared to PLA/GA-NF. In addition, GA was released slowly from PLA/GA/HPβCD-IC-NF into 95% ethanol when compared to PLA/GA-NF. It was also observed that electrospinning process had no negative effect on the antioxidant activity of GA when GA was incorporated in PLA nanofibers.

  12. CyPPA, a Positive SK3/SK2 Modulator, Reduces Activity of Dopaminergic Neurons, Inhibits Dopamine Release, and Counteracts Hyperdopaminergic Behaviors Induced by Methylphenidate.

    PubMed

    Herrik, Kjartan F; Redrobe, John P; Holst, Dorte; Hougaard, Charlotte; Sandager-Nielsen, Karin; Nielsen, Alexander N; Ji, Huifang; Holst, Nina M; Rasmussen, Hanne B; Nielsen, Elsebet Ø; Strøbæk, Dorte; Shepard, Paul D; Christophersen, Palle

    2012-01-01

    Dopamine (DA) containing midbrain neurons play critical roles in several psychiatric and neurological diseases, including schizophrenia and attention deficit hyperactivity disorder, and the substantia nigra pars compacta neurons selectively degenerate in Parkinson's disease. Pharmacological modulation of DA receptors and transporters are well established approaches for treatment of DA-related disorders. Direct modulation of the DA system by influencing the discharge pattern of these autonomously firing neurons has yet to be exploited as a potential therapeutic strategy. Small conductance Ca(2+)-activated K(+) channels (SK channels), in particular the SK3 subtype, are important in the physiology of DA neurons, and agents modifying SK channel activity could potentially affect DA signaling and DA-related behaviors. Here we show that cyclohexyl-[2-(3,5-dimethyl-pyrazol-1-yl)-6-methyl-pyrimidin-4-yl]-amine (CyPPA), a subtype-selective positive modulator of SK channels (SK3 > SK2 > > > SK1, IK), decreased spontaneous firing rate, increased the duration of the apamin-sensitive afterhyperpolarization, and caused an activity-dependent inhibition of current-evoked action potentials in DA neurons from both mouse and rat midbrain slices. Using an immunocytochemically and pharmacologically validated DA release assay employing cultured DA neurons from rats, we show that CyPPA repressed DA release in a concentration-dependent manner with a maximal effect equal to the D2 receptor agonist quinpirole. In vivo studies revealed that systemic administration of CyPPA attenuated methylphenidate-induced hyperactivity and stereotypic behaviors in mice. Taken together, the data accentuate the important role played by SK3 channels in the physiology of DA neurons, and indicate that their facilitation by CyPPA profoundly influences physiological as well as pharmacologically induced hyperdopaminergic behavior.

  13. Behavior and movement of adult summer steelhead following collection and release, lower Cowlitz River, Washington, 2012--2013

    USGS Publications Warehouse

    Kock, Tobias J.; Liedtke, Theresa L.; Ekstrom, Brian K.; Rondorf, Dennis W.; Gleizes, Chris; Dammers, Wolf; Gibson, Scott; Murphy, Jamie

    2013-01-01

    Historically, adult summer steelhead Oncorhynchus mykiss returning to hatcheries on the lower Cowlitz River were sometimes transported and released in the river (recycled) to provide additional angling opportunity for the popular sport fishery in the basin. However, this practice has not been used in recent years because of concerns associated with interactions between hatchery fish and wild fish. Fishery managers were interested in resuming recycling but lacked information regarding effects of this practice on wild steelhead so we conducted a study during 2012–2013 to: (1) enumerate recycled steelhead that returned to the hatchery or were removed by anglers; and (2) determine if steelhead that were not removed from the river remained in the system where they could interact with wild fish. During June–August 2012, a total of 549 summer steelhead were captured at the Cowlitz Salmon Hatchery, tagged, and released downstream near the Interstate 5 Bridge. All recycled steelhead were tagged with a white Floy® tag and opercle-punched; 109 (20 percent) of these fish also were radio-tagged. All adult steelhead that return to the hatchery were handled by hatchery staff so recycled steelhead that returned to the hatchery were enumerated daily. A creel survey and voluntary angler reports were used to determine the number of recycled steelhead that were caught by anglers. We established three fixed telemetry monitoring sites on the mainstem Cowlitz River and eight additional sites were deployed on tributaries to the lower Cowlitz River where wild winter steelhead are known to spawn. We also conducted mobile tracking from a boat during October 2012, November 2012, and January 2013 to locate radio-tagged fish. A total of 10,722 summer steelhead were captured at the Cowlitz Salmon Hatchery in 2012, which was the largest return since 2008. River flows during much of the study period were similar to 2008–2011 average flows, however, high-flow periods in July and November

  14. Noise stress changes mRNA expressions of corticotropin-releasing hormone, its receptors in amygdala, and anxiety-related behaviors.

    PubMed

    Eraslan, Evren; Akyazi, Ibrahim; Erg L-Ekiz, Elif; Matur, Erdal

    2015-01-01

    Noise is a psychological, environmental stressor that activates limbic sites in the brain. Limbic sites such as the amygdala and the amygdaloid corticotropin-releasing hormone (CRH) system play an important role in integrating stress response. We investigated the association between noise exposures, CRH-related molecules in the amygdala, and behavioral alterations. In total 54 Sprague-Dawley rats were divided into the following three groups: Control (CON), acute noise exposure (ANE), and chronic noise exposure (CNE). The ANE group was exposed to 100 dB white noise only once in 4 h and the CNE group was exposed to the same for 4 h per day for 30 days. Expression profiles of CRH and its receptors CRH-R1 and CRH-R2 were analyzed by quantitative real-time polymerase chain reaction (qPCR). The same stress procedure was applied to the ANE and CNE groups for behavior testing. The anxiety responses of the animals after acute and chronic stress exposure were measured in the defensive withdrawal test. CNE upregulated CRH and CRH-R1 mRNA levels but downregulated CRH-R2 mRNA levels. ANE led to a decrease in both CRH-R1 and CRH-R2 expression. In the defensive withdrawal test, while the ANE increased, CNE reduced anxiety-like behaviors. The present study shows that the exposure of rats to white noise (100 dB) leads to behavioral alterations and molecule-specific changes in the CRH system. Behavioral alterations can be related to these molecular changes in the amygdala.

  15. Mice that gorged during dietary restriction increased foraging related behaviors and differed in their macronutrient preference when released from restriction

    PubMed Central

    Speakman, John R.

    2015-01-01

    Caloric restriction (CR) can trigger gorging behavior. We examined macronutrient choice and behavior in mice that gorged during restriction compared to restricted non-gorgers and controls. Fifty MF1 male mice were restricted to 75% of ad-libitum food intake (FI), while ten controls were fed ad-lib. Body mass (BM) and FI were measured two and 24-h after food inclusion over 14-days. ‘Gorging’ mice were defined as those which ate over 25% of their daily FI in 2-h. The top 11 gorgers and the lowest 9 gorgers, along with 10 controls, had their behavior analysed during restriction, and were then provided with an unrestricted food choice, consisting of three diets that were high in fat, protein or carbohydrate. During restriction gorgers ate on average 51% of their daily FI in the 2-h following food introduction while the non-gorgers ate only 16%. Gorgers lost significantly more BM than non-gorgers possibly due to an increased physical activity linked to anticipation of daily food provision. Controls and non-gorgers spent most of their time sleeping. After restriction, both gorgers and non-gorgers were hyperphagic until their lost weight was regained. All 3 groups favoured high fat food. Gorgers and non-gorgers had a significantly greater high carbohydrate diet intake than controls, and gorgers also had a significantly greater high protein diet intake than non-gorgers and controls. On unrestricted food, they did not continue to gorge, although they still had a significantly greater 2-h FI than the other groups. Elevated protein intake may play an important role in the recovery of the lost lean tissue of gorgers after restriction. PMID:26157640

  16. Effect of aqueous media on the copper-ion-mediated phototoxicity of CuO nanoparticles toward green fluorescent protein-expressing Escherichia coli.

    PubMed

    Shang, Enxiang; Li, Yang; Niu, Junfeng; Guo, Huiyuan; Zhou, Yijing; Liu, Han; Zhang, Xinqi

    2015-12-01

    Quantitative comparison of different aqueous media on the phototoxicity of copper oxide nanoparticles (CuO NPs) is crucial for understanding their ecological effects. In this study, the phototoxicity of CuO NPs toward the green fluorescent protein-expressing Escherichia coli (GFP-E. coli) under UV irradiation (365 nm) was investigated in Luria-Bertani medium (LB), NaCl solution, deionized water (DI) and phosphate-buffered saline (PBS). The phototoxicity of CuO NPs toward GFP-E. coli decreased in the order of DI>NaCl>PBS>LB because of different released concentrations of Cu(2+). The 3h released Cu(2+) concentrations by 10mg/L CuO NPs in DI water, NaCl solution, LB medium, and PBS were 1946.3 ± 75.6, 1242.5 ± 47.6, 1023.4 ± 41.2, and 1162.1 ± 41.9 μg/L, respectively. Transmission electron microscope and laser scanning confocal microscope images of E. coli exposed to CuO NPs demonstrated that the released Cu(2+) resulted in fragmentation of bacterial cell walls, leakage of intracellular components, and finally death of bacteria in four media after UV light irradiation. In each medium, the bacterial mortality rate logarithmically increased with the releasing concentrations of Cu(2+) by CuO NPs (R(2)>0.90) exposed to 3h UV light. This study highlights the importance of taking into consideration of water chemistry when the phototoxicity of CuO NPs is assessed in nanotoxicity research.

  17. Effects of gonadotropin-releasing hormone immunization on reproductive function and behavior in captive female Rocky Mountain elk (Cervus elaphus nelsoni).

    PubMed

    Powers, Jenny G; Baker, Dan L; Davis, Tracy L; Conner, Mary M; Lothridge, Anneke H; Nett, Terry M

    2011-12-01

    Fertility control is a potential method for managing overabundant wildlife populations; however, current technology is limited by duration of treatment efficacy and unacceptable side effects. The objective of this study was to determine the efficacy of a single immunization with gonadotropin-releasing hormone (GnRH) vaccine to suppress reproductive function in pregnant female elk and to evaluate potential behavioral and pathological side effects of treatment. Eighteen captive adult female elk were randomly allocated to one of two experimental groups. Ten females were administered a conjugated and adjuvanted GnRH vaccine intramuscularly, and eight elk received an adjuvant sham vaccine without conjugated GnRH. We compared success of existing pregnancy, neonatal survival, subsequent fertility, reproductive behavior rates, and side effects of treatment between January 2006 and January 2010. The GnRH vaccination did not affect existing pregnancy or calf survival during the year that it was applied; however, it reduced the proportion of pregnant females for 3 yr. Male precopulatory behavior rates exhibited toward GnRH-vaccinated females tended to be greater than those directed at sham-vaccinated females during the second half of the breeding season, when GnRH vaccinates continued to be proceptive. Strong immune and inflammatory responses, including robust GnRH antibody concentrations in GnRH vaccinates, and sterile pyogranulomatous injection site abscesses in both groups, were consistent with vaccination. In conclusion, this GnRH vaccine resulted in prolonged, albeit reversible, impairment of fertility, and is associated with extended reproductive behaviors and partial suppression of hypothalamic-pituitary-gonadal axis function in captive female elk.

  18. Effects of prolonged ethanol vapor exposure on forced swim behavior, and neuropeptide Y and corticotropin-releasing factor levels in rat brains.

    PubMed

    Walker, Brendan M; Drimmer, David A; Walker, Jennifer L; Liu, Tianmin; Mathé, Aleksander A; Ehlers, Cindy L

    2010-09-01

    Depressive symptoms in alcohol-dependent individuals are well-recognized and clinically relevant phenomena. The etiology has not been elucidated although it is clear that the depressive symptoms may be alcohol independent or alcohol induced. To contribute to the understanding of the neurobiology of chronic ethanol use, we investigated the effects of chronic intermittent ethanol vapor exposure on behaviors in the forced swim test (FST) and neuropeptide Y (NPY) and corticotropin-releasing factor (CRF) levels in specific brain regions. Adult male Wistar rats were subjected to intermittent ethanol vapor (14 h on/10 h off) or air exposure for 2 weeks and were then tested at three time points corresponding to acute withdrawal (8-12 h into withdrawal) and protracted withdrawal (30 and 60 days of withdrawal) in the FST. The behaviors that were measured in the five-min FST consisted of latency to immobility, swim time, immobility time, and climbing time. The FST results showed that the vapor-exposed animals displayed depressive-like behaviors; for instance, decreased latency to immobility in acute withdrawal and decreased latency to immobility, decreased swim time and increased immobility time in protracted withdrawal, with differences between air- and vapor-exposed animals becoming more pronounced over the 60-day withdrawal period. NPY levels in the frontal cortex of the vapor-exposed animals were decreased compared with the control animals, and CRF levels in the amygdala were correlated with increased immobility time. Thus, extended ethanol vapor exposure produced long-lasting changes in FST behavior and NPY levels in the brain.

  19. Activation of corticotropin-releasing factor receptors from the basolateral or central amygdala increases the tonic immobility response in guinea pigs: an innate fear behavior.

    PubMed

    Donatti, Alberto Ferreira; Leite-Panissi, Christie Ramos Andrade

    2011-11-20

    The tonic immobility (TI) behavior is an innate response associated with extreme threat situations such as a predator attack. Several studies have provided evidence suggesting an important role for corticotropin-releasing factor (CRF) in the regulation of the endocrine system, defensive behaviors and behavioral responses to stress. TI has been shown to be positively correlated with the basal plasma levels of corticosterone. CRF receptors and neurons that are immunoreactive to CRF are found in many cerebral regions, especially in the amygdaloid complex. Previous reports have demonstrated the involvement of the basolateral amygdaloid (BLA) and central amygdaloid (CeA) nuclei in the TI response. In this study, we evaluated the CRF system of the BLA and the CeA in the modulation of the TI response in guinea pigs. The activation of CRF receptors in the BLA and in the CeA promoted an increase in the TI response. In contrast, the inhibition of these receptors via alpha-helical-CRF(9-41) decreased the duration of the TI response. Moreover, neither the activation nor inhibition of CRF receptors in the BLA or the CeA altered spontaneous motor activity in the open-field test. These data suggest that the activation of the CRF receptors in the BLA or the CeA probably potentiates fear and anxiety, which may be one of the factors that promote an increase in the TI behavior. Therefore, these data support the role of the CRF system in the control of emotional responses, particularly in the modulation of innate fear.

  20. Early-life stress-induced anxiety-related behavior in adult mice partially requires forebrain corticotropin-releasing hormone receptor 1.

    PubMed

    Wang, Xiao-Dong; Labermaier, Christiana; Holsboer, Florian; Wurst, Wolfgang; Deussing, Jan M; Müller, Marianne B; Schmidt, Mathias V

    2012-08-01

    Early-life stress may lead to persistent changes in central corticotropin-releasing hormone (CRH) and the CRH receptor 1 (CRHR1) system that modulates anxiety-related behavior. However, it remains unknown whether CRH-CRHR1 signaling is involved in early-life stress-induced anxiety-related behavior in adult animals. In the present study, we used conditional forebrain CRHR1 knockout (CRHR1-CKO) mice and examined the potential role of forebrain CRHR1 in the anxiogenic effects of early-life stress. As adults, wild-type mice that received unstable maternal care during the first postnatal week showed reduced body weight gain and increased anxiety levels in the open field test, which were prevented in stressed CRHR1-CKO mice. In the light-dark box test, control CRHR1-CKO mice were less anxious, but early-life stress increased anxiety levels in both wild-type and CRHR1-CKO mice. In the elevated plus maze test, early-life stress had only subtle effects on anxiety-related behavior. Moreover, early-life stress did not alter the basal home cage activity and gene expression levels of key hypothalamic-pituitary-adrenal axis regulators in adult wild-type and CRHR1-CKO mice, but enhanced neuroendocrine reactivity to acute immobilization stress in CRHR1-CKO mice. Our findings highlight the importance of forebrain CRHR1 in modulating some of the anxiogenic effects of early-life stress, and suggest that other neural circuits are also involved in the programming effects of early-life stress on anxiety-related behavior.

  1. Corticotropin-releasing factor (CRF) and neuropeptide Y (NPY): effects on inhibitory transmission in central amygdala, and anxiety- & alcohol-related behaviors.

    PubMed

    Gilpin, Nicholas W

    2012-06-01

    The central amygdala (CeA) is uniquely situated to function as an interface between stress- and addiction-related processes. This brain region has long been attributed an important role in aversive (e.g., fear) conditioning, as well as the negative emotional states that define alcohol dependence and withdrawal. The CeA is the major output region of the amygdala and receives complex inputs from other amygdaloid nuclei as well as regions that integrate sensory information from the external environment (e.g., thalamus, cortex). The CeA is functionally and anatomically divided into lateral and medial subdivisions that themselves are interconnected and populated by inhibitory interneurons and projections neurons. Neuropeptides are highly expressed in the CeA, particularly in the lateral subdivision, and the role of many of these peptides in regulating anxiety- and alcohol-related behaviors has been localized to the CeA. This review focuses on two of these peptides, corticotropin-releasing factor (CRF) and neuropeptide Y (NPY), that exhibit a high degree of neuroanatomical overlap (e.g., in CeA) and largely opposite behavioral profiles (e.g., in regulating anxiety- and alcohol-related behavior). CRF and NPY systems in the CeA appear to be recruited and/or up-regulated during the transition to alcohol dependence. These and other neuropeptides may converge on GABA synapses in CeA to control projection neurons and downstream effector regions, thereby translating negative affective states into anxiety-like behavior and excessive alcohol consumption.

  2. Gonadotropin-releasing hormone receptor (Gnrhr) gene knock out: Normal growth and development of sensory, motor and spatial orientation behavior but altered metabolism in neonatal and prepubertal mice.

    PubMed

    Busby, Ellen R; Sherwood, Nancy M

    2017-01-01

    Gonadotropin-releasing hormone (GnRH) is important in the control of reproduction, but its actions in non-reproductive processes are less well known. In this study we examined the effect of disrupting the GnRH receptor in mice to determine if growth, metabolism or behaviors that are not associated with reproduction were affected. To minimize the effects of other hormones such as FSH, LH and sex steroids, the neonatal-prepubertal period of 2 to 28 days of age was selected. The study shows that regardless of sex or phenotype in the Gnrhr gene knockout line, there was no significant difference in the daily development of motor control, sensory detection or spatial orientation among the wildtype, heterozygous or null mice. This included a series of behavioral tests for touch, vision, hearing, spatial orientation, locomotory behavior and muscle strength. Neither the daily body weight nor the final weight on day 28 of the kidney, liver and thymus relative to body weight varied significantly in any group. However by day 28, metabolic changes in the GnRH null females compared with wildtype females showed a significant reduction in inguinal fat pad weight normalized to body weight; this was accompanied by an increase in glucose compared with wildtype females shown by Student-Newman-Keuls Multiple Comparison test and Student's unpaired t tests. Our studies show that the GnRH-GnRHR system is not essential for growth or motor/sensory/orientation behavior during the first month of life prior to puberty onset. The lack of the GnRH-GnRHR axis, however, did affect females resulting in reduced subcutaneous inguinal fat pad weight and increased glucose with possible insulin resistance; the loss of the normal rise of estradiol at postnatal days 15-28 may account for the altered metabolism in the prepubertal female pups.

  3. Gonadotropin-releasing hormone receptor (Gnrhr) gene knock out: Normal growth and development of sensory, motor and spatial orientation behavior but altered metabolism in neonatal and prepubertal mice

    PubMed Central

    Busby, Ellen R.; Sherwood, Nancy M.

    2017-01-01

    Gonadotropin-releasing hormone (GnRH) is important in the control of reproduction, but its actions in non-reproductive processes are less well known. In this study we examined the effect of disrupting the GnRH receptor in mice to determine if growth, metabolism or behaviors that are not associated with reproduction were affected. To minimize the effects of other hormones such as FSH, LH and sex steroids, the neonatal-prepubertal period of 2 to 28 days of age was selected. The study shows that regardless of sex or phenotype in the Gnrhr gene knockout line, there was no significant difference in the daily development of motor control, sensory detection or spatial orientation among the wildtype, heterozygous or null mice. This included a series of behavioral tests for touch, vision, hearing, spatial orientation, locomotory behavior and muscle strength. Neither the daily body weight nor the final weight on day 28 of the kidney, liver and thymus relative to body weight varied significantly in any group. However by day 28, metabolic changes in the GnRH null females compared with wildtype females showed a significant reduction in inguinal fat pad weight normalized to body weight; this was accompanied by an increase in glucose compared with wildtype females shown by Student-Newman-Keuls Multiple Comparison test and Student's unpaired t tests. Our studies show that the GnRH-GnRHR system is not essential for growth or motor/sensory/orientation behavior during the first month of life prior to puberty onset. The lack of the GnRH-GnRHR axis, however, did affect females resulting in reduced subcutaneous inguinal fat pad weight and increased glucose with possible insulin resistance; the loss of the normal rise of estradiol at postnatal days 15–28 may account for the altered metabolism in the prepubertal female pups. PMID:28346489

  4. Synthesis of nano-sized stereoselective imprinted polymer by copolymerization of (S)-2-(acrylamido) propanoic acid and ethylene glycol dimethacrylate in the presence of racemic propranolol and copper ion.

    PubMed

    Alizadeh, Taher; Bagherzadeh, Azam; Shamkhali, Amir Nasser

    2016-06-01

    A new chiral functional monomer of (S)-2-(acrylamido) propanoic acid was obtained by reaction of (l)-alanine with acryloyl chloride. The resulting monomer was characterized by FT-IR and HNMR and then utilized for the preparation of chiral imprinted polymer (CIP). This was carried out by copolymerization of (l)-alanine-derived chiral monomer and ethylene glycol dimethacrylate, in the presence of racemic propranolol and copper nitrate, via precipitation polymerization technique, resulting in nano-sized networked polymer particles. The polymer obtained was characterized by scanning electron microscopy and FT-IR. The non-imprinted polymer was also synthesized and used as blank polymer. Density functional theory (DFT) was also employed to optimize the structures of two diasterometric ternary complexes, suspected to be created in the pre-polymerization step, by reaction of optically active isomers of propranolol, copper ion and (S)-2-(acrylamido) propanoic acid. Relative energies and other characteristics of the described complexes, calculated by the DFT, predicted the higher stability of (S)-propranolol involved complex, compared to (R)-propranolol participated complex. Practical batch extraction test which employed CIP as solid phase adsorbent, indicated that the CIP recognized selectively (S)-propranolol in the racemic mixture of propranolol; whereas, the non-imprinted polymer (NIP) showed no differentiation capability between two optically active isomers of propranolol.

  5. Dual drug load and release behavior on ion-exchange fiber: influencing factors and prediction method for precise control of the loading amount.

    PubMed

    Yuan, Jing; Gao, Yanan; Liu, Tiaotiao; Wang, Xinyu; Liu, Hongzhuo; Li, Sanming

    2015-01-01

    Ion-exchange fiber undergoes a stoichiometric exchange reaction and has large exchange capability, which makes it a promising candidate as a multiple drug carrier. Because combinatorial effects can act synergistically, additively or antagonistically depending on the ratio of the agents being combined, the objective of this study was to learn the dual drug loading of ion-exchange fiber and develop a mathematical method for precisely control of the loading amount. Atenolol and Gatifloxacin, with different loading behaviors into strong cationic ion-exchange fiber ZB-1, were used to build a representative of dual loading. Not suitable pH value of drug solutions could make simultaneous loading fail, while the change of drug solution volume hardly affected the equilibrium. Ion-exchange groups occupied by the drug which owned lower affinity to fiber could be grabbed by the higher affinity drug, indicating the existence of competition between drugs. Thermodynamic model was introduced to guide the loading prediction and a favorable relevance had been shown between determined and predicted data. The release behaviors of each drug from dual drug-fiber complex were similar to those from single drug-fiber complexes.

  6. Effects of acute treadmill running at different intensities on activities of serotonin and corticotropin-releasing factor neurons, and anxiety- and depressive-like behaviors in rats.

    PubMed

    Otsuka, Tomomi; Nishii, Ayu; Amemiya, Seiichiro; Kubota, Natsuko; Nishijima, Takeshi; Kita, Ichiro

    2016-02-01

    Accumulating evidence suggests that physical exercise can reduce and prevent the incidence of stress-related psychiatric disorders, including depression and anxiety. Activation of serotonin (5-HT) neurons in the dorsal raphe nucleus (DRN) is implicated in antidepressant/anxiolytic properties. In addition, the incidence and symptoms of these disorders may involve dysregulation of the hypothalamic-pituitary-adrenal axis that is initiated by corticotropin-releasing factor (CRF) neurons in the hypothalamic paraventricular nucleus (PVN). Thus, it is possible that physical exercise produces its antidepressant/anxiolytic effects by affecting these neuronal activities. However, the effects of acute physical exercise at different intensities on these neuronal activation and behavioral changes are still unclear. Here, we examined the activities of 5-HT neurons in the DRN and CRF neurons in the PVN during 30 min of treadmill running at different speeds (high speed, 25 m/min; low speed, 15m/min; control, only sitting on the treadmill) in male Wistar rats, using c-Fos/5-HT or CRF immunohistochemistry. We also performed the elevated plus maze test and the forced swim test to assess anxiety- and depressive-like behaviors, respectively. Acute treadmill running at low speed, but not high speed, significantly increased c-Fos expression in 5-HT neurons in the DRN compared to the control, whereas high-speed running significantly enhanced c-Fos expression in CRF neurons in the PVN compared with the control and low-speed running. Furthermore, low-speed running resulted in decreased anxiety- and depressive-like behaviors compared with high-speed running. These results suggest that acute physical exercise with mild and low stress can efficiently induce optimal neuronal activation that is involved in the antidepressant/anxiolytic effects.

  7. The non-steroidal anti-inflammatory drug diclofenac sodium attenuates lipopolysaccharide-induced alterations to reward behavior and corticosterone release.

    PubMed

    De La Garza, Richard; Fabrizio, Kevin R; Radoi, Gina Elena; Vlad, Tudor; Asnis, Gregory M

    2004-02-04

    Non-steroidal anti-inflammatory drugs (NSAIDs) have been shown to counteract stress hormone and pro-inflammatory cytokine activation. To extend these findings, we tested whether the NSAID diclofenac sodium would attenuate lipopolysaccharide (LPS)-induced reductions in reward behavior. In the first experiment, male, Wistar rats pressed a lever for food reward and subsequently received 10 days treatment of saline (1 ml/kg, s.c.) or diclofenac (2.5mg/kg, s.c.). On the subsequent test day, rats were given a final injection of saline or diclofenac 30 min prior to LPS (20 micrograms/kg, i.p.). LPS significantly reduced rate of food self-administration and total reinforcers obtained and increased corticosterone levels in saline-treated rats, while these effects were significantly attenuated in diclofenac-treated rats. In the second experiment, rats pressed a lever for sweetened milk. In contrast to food self-administration, acute LPS exposure did not reduce rate of responding or total reinforcers obtained in either saline- or diclofenac-treated rats. In the third experiment, rats trained to press a lever for sweetened milk were pre-exposed to a high dose of LPS (250 micrograms/kg, i.p.) 2 weeks prior to a challenge injection of LPS. In this case, LPS challenge significantly reduced rate of sweetened milk self-administration, but not total reinforcers obtained, in saline-treated rats. Rats treated with diclofenac did not exhibit reductions in rate of responding or total reinforcers obtained. Overall, the data indicate that the NSAID diclofenac sodium counteracts LPS-induced reductions in reward behavior and corticosterone release, and may therefore have therapeutic potential for specific components of endotoxin-induced sickness behavior, including anhedonia.

  8. Cross-generational effects of parental low dose BPA exposure on the Gonadotropin-Releasing Hormone3 system and larval behavior in medaka (Oryzias latipes).

    PubMed

    Inagaki, T; Smith, N L; Sherva, K M; Ramakrishnan, S

    2016-12-01

    Growing evidence indicates that chronic exposure to Bisphenol A (BPA) may disrupt normal brain function and behavior mediated by gonadotropin-releasing hormone (GnRH) pathways. Previous studies have shown that low dose BPA (200ng/ml) exposure during embryogenesis altered development of extra-hypothalamic GnRH3 systems and non-reproductive locomotor behavior in medaka. Effects of parental low-dose BPA exposure on the development of GnRH3 systems and locomotor behavior of offspring are not well known. This study examines whether the neurophysiological and behavioral effects of BPA in parents (F0 generation) are carried over to their offspring (F1 generation) using stable transgenic medaka embryos/larvae with GnRH3 neurons tagged with green fluorescent protein (GFP). Parental fish were exposed to BPA (200ng/ml) for either life-long or different developmental time windows. Fertilized F1 eggs were collected and raised in egg/fish water with no environmental exposure to BPA. All experiments were performed on F1 embryos/larvae, which were grouped based on the following parental (F0) BPA exposure conditions - (i) Group 1 (G1): through life; (ii) G2: during embryogenesis and early larval development [1-14days post fertilization (dpf)]; (iii) G3: during neurogenesis (1-5dpf); and (iv) G4: during sex differentiation (5-14dpf). Embryos from unexposed vehicle treated parents served as controls (G0). G1 embryos showed significantly reduced survival rates and delayed hatching time compared to other groups, while G4 embryos hatched significantly earlier than all other groups. At 3 dpf, the GnRH3-GFP intensity was increased by 47% in G3 embryos and decreased in G4 embryos by 59% compared to controls. At 4dpf, G1 fish showed 42% increased intensity, while GFP intensity was reduced by 44% in G3 subjects. In addition, the mean brain size of G1, G3 and G4 embryos were smaller than that of control at 4dpf. At 20dpf, all larvae from BPA-treated parents showed significantly decreased

  9. A poly(glycerol sebacate)-coated mesoporous bioactive glass scaffold with adjustable mechanical strength, degradation rate, controlled-release and cell behavior for bone tissue engineering.

    PubMed

    Lin, Dan; Yang, Kai; Tang, Wei; Liu, Yutong; Yuan, Yuan; Liu, Changsheng

    2015-07-01

    Various requirements in the field of tissue engineering have motivated the development of three-dimensional scaffold with adjustable physicochemical properties and biological functions. A series of multiparameter-adjustable mesoporous bioactive glass (MBG) scaffolds with uncrosslinked poly(glycerol sebacate) (PGS) coating was prepared in this article. MBG scaffold was prepared by a modified F127/PU co-templating process and then PGS was coated by a simple adsorption and lyophilization process. Through controlling macropore parameters and PGS coating amount, the mechanical strength, degradation rate, controlled-release and cell behavior of the composite scaffold could be modulated in a wide range. PGS coating successfully endowed MBG scaffold with improved toughness and adjustable mechanical strength covering the bearing range of trabecular bone (2-12MPa). Multilevel degradation rate of the scaffold and controlled-release rate of protein from mesopore could be achieved, with little impact on the protein activity owing to an "ultralow-solvent" coating and "nano-cavity entrapment" immobilization method. In vitro studies indicated that PGS coating promoted cell attachment and proliferation in a dose-dependent manner, without affecting the osteogenic induction capacity of MBG substrate. These results first provide strong evidence that uncrosslinked PGS might also yield extraordinary achievements in traditional MBG scaffold. With the multiparameter adjustability, the composite MBG/PGS scaffolds would have a hopeful prospect in bone tissue engineering. The design considerations and coating method of this study can also be extended to other ceramic-based artificial scaffolds and are expected to provide new thoughts on development of future tissue engineering materials.

  10. Application of micro-segmented flow for two-dimensional characterization of the combinatorial effect of zinc and copper ions on metal-tolerant Streptomyces strains.

    PubMed

    Cao, Jialan; Kürsten, Dana; Krause, Katrin; Kothe, Erika; Martin, Karin; Roth, Martin; Köhler, J Michael

    2013-10-01

    The cultivation and growth behavior of metal-tolerant strains of Streptomyce acidiscabies E13 and Streptomyces sp. F4 were studied under droplet-based microfluidics conditions. It was shown that the technique of micro segmented flow is well suited for the investigation of dependence of bacterial growth on different concentrations of either single metal ions or combinations of them. This study confirms higher tolerance to Zn than to Cu by our test organism. The highly resolved dose-response curves reflect two transitions between the different growth behaviors, separating initial responses to Cu concentration ranges into those with (a) intense growth, (b) moderate growth, and (c) growth inhibition. For Streptomyces sp. F4, an initial stimulation was shown in the sublethal range of zinc sulfate. Two-dimensional screenings using computer-controlled fluid actuation and in situ micro flow-through fluorimetry reflected a strong growth stimulation of strain F4 by zinc sulfate in the presence of sublethal Cu concentrations. This stimulatory effect on binary mixtures may be useful in providing optimal growth conditions in bioremediation procedures.

  11. Irradiation route to aqueous synthesis of highly luminescent ZnSe quantum dots and its function as a copper ion fluorescence sensor

    SciTech Connect

    Rao, Yeluri Narayana; Datta, Aparna

    2016-08-15

    Highlights: • Radiation chemical technique can provide a useful route for synthesis of ZnSe QDs. • Chelating nature of ethylene diamine is exploited for capping nanoparticles. • ZnSe QDs can be a suitable sensitive alternative to toxic cadmium-based system. • Cu(II) ion is probed by QDs in the presence of other physiologically relevant ions. - Abstract: Size-controlled synthesis of stable ZnSe QDs with narrow distribution in aqueous environment through conventional soft chemical method still poses a challenge. The proposed radiation assisted strategy demonstrates aqueous synthesis of stable, monodisperse and luminescent ZnSe QDs capped with chelating ethylene diamine under ambient conditions and at room temperature. Radiation chemical method facilitates in slow and in-situ release of selenium ion from sodium selenosulfate. The concentrations of precursors, such as zinc salt, selenium source, ethylene diamine and absorbed radiation (7–90 kGy) dose were optimized for obtaining good quality particles. Selective quenching of luminescence of as-synthesized quantum dots (QDs) by Cu{sup 2+} ions vis-à-vis other physiologically important cations provide evidence for use of ZnSe quantum dots as alternative to toxic Cd-based quantum dots to probe Cu{sup 2+} ions. The linear relation of ratio of loss in emission intensity as a function of concentration of Cu(II) indicates detection limit in nano-molar range.

  12. Behaviorism

    ERIC Educational Resources Information Center

    Moore, J.

    2011-01-01

    Early forms of psychology assumed that mental life was the appropriate subject matter for psychology, and introspection was an appropriate method to engage that subject matter. In 1913, John B. Watson proposed an alternative: classical S-R behaviorism. According to Watson, behavior was a subject matter in its own right, to be studied by the…

  13. Low dose exposure to Bisphenol A alters development of gonadotropin-releasing hormone 3 neurons and larval locomotor behavior in Japanese Medaka.

    PubMed

    Inagaki, T; Smith, N; Lee, E K; Ramakrishnan, S

    2016-01-01

    Accumulating evidence indicates that chronic low dose exposure to Bisphenol A (BPA), an endocrine disruptor, may disrupt normal brain development and behavior mediated by the gonadotropin-releasing hormone (GnRH) pathways. While it is known that GnRH neurons in the hypothalamus regulate reproductive physiology and behavior, functional roles of extra-hypothalamic GnRH neurons remain unclear. Furthermore, little is known whether BPA interacts with extra-hypothalamic GnRH3 neural systems in vulnerable developing brains. Here we examined the impact of low dose BPA exposure on the developing GnRH3 neural system, eye and brain growth, and locomotor activity in transgenic medaka embryos and larvae with GnRH3 neurons tagged with GFP. Fertilized eggs were collected daily and embryos/larvae were chronically exposed to 200ng/ml of BPA, starting at 1 day post fertilization (dpf). BPA significantly increased fluorescence intensity of the GnRH3-GFP neural population in the terminal nerve (TN) of the forebrain at 3dpf, but decreased the intensity at 5dpf, compared with controls. BPA advanced eye pigmentation without affecting eye and brain size development, and accelerated times to hatch. Following chronic BPA exposure, 20dpf larvae showed suppression of locomotion, both in distance covered and speed of movement (47% and 43% reduction, respectively). BPA-induced hypoactivity was accompanied by decreased cell body sizes of individual TN-GnRH3 neurons (14% smaller than those of controls), but not of non-GnRH3 neurons. These novel data demonstrate complex neurobehavioral effects of BPA on the development of extra-hypothalamic GnRH3 neurons in teleost fish.

  14. Biodynamics of copper oxide nanoparticles and copper ions in an oligochaete: Part I: relative importance of water and sediment as exposure routes

    USGS Publications Warehouse

    Ramskov, Tina; Thit, Amalie; Croteau, Marie-Noele; Selck, Henriette

    2015-01-01

    Copper oxide (CuO) nanoparticles (NPs) are widely used, and likely released into the aquatic environment. Both aqueous (i.e., dissolved Cu) and particulate Cu can be taken up by organisms. However, how exposure routes influence the bioavailability and subsequent toxicity of Cu remains largely unknown. Here, we assess the importance of exposure routes (water and sediment) and Cu forms (aqueous and nanoparticulate) on Cu bioavailability and toxicity to the freshwater oligochaete, Lumbriculus variegatus, a head-down deposit-feeder. We characterize the bioaccumulation dynamics of Cu in L. variegatus across a range of exposure concentrations, covering both realistic and worst-case levels of Cu contamination in the environment. Both aqueous Cu (Cu-Aq; administered as Cu(NO3)2) and nanoparticulate Cu (CuO NPs), whether dispersed in artificial moderately hard freshwater or mixed into sediment, were weakly accumulated by L. variegatus. Once incorporated into tissues, Cu elimination was negligible, i.e., elimination rate constants were in general not different from zero for either exposure route or either Cu form. Toxicity was only observed after waterborne exposure to Cu-Aq at very high concentration (305 µgL-1), where all worms died. There was no relationship between exposure route, Cu form or Cu exposure concentration on either worm survival or growth. Slow feeding rates and low Cu assimilation efficiency (approximately 30%) characterized the uptake of Cu from the sediment for both Cu forms. In nature, L. variegatus is potentially exposed to Cu via both water and sediment. However, sediment progressively becomes the predominant exposure route for Cu in L. variegatus as Cu partitioning to sediment increases.

  15. The activation of nitric oxide synthase by copper ion is mediated by intracellular Ca2+ mobilization in human pulmonary arterial endothelial cells

    PubMed Central

    Demura, Yoshiki; Ishizaki, Takeshi; Ameshima, Shingo; Okamura, Seitarou; Hayashi, Takio; Matsukawa, Shigeru; Miyamori, Isamu

    1998-01-01

    The aim of the study was to elucidate the vasodilatory mechanism due to Cu2+ by assessing nitric oxide (NO) production as determined by NOx (NO, NO2−, and NO3−) that is released from human pulmonary arterial endothelial cell (HPAEC) monolayers using a NO chemiluminescence analyzer, and also to assess Ca2+ movement using 45Ca and fura 2 in HPAEC.Cu2+ (10−6–10−4 M) significantly increased NO production in a dose-dependent manner when extracellular Ca2+ was present.45Ca influx into the adherent cells was dose-dependently enhanced by Cu2+ (10−6–10−4 M), but not by Mn2+, Zn2+ or Fe2+.[Ca2+]i, measured by monitoring the fluorescence changes of fura 2, was significantly elevated in the presence of Cu2+.The increase in [Ca2+]i induced by Cu2+ was inhibited by either diethyldithiocarbamate (DDC) or the depletion of extracellular Ca2+.The dihydropyridine receptor agonist, BayK8644, significantly attenuated the Cu2+-induced increase in [Ca2+]i in a dose dependent manner and nitrendipine or nifedipine, the dihydropyridine receptor antagonists, dose-dependently inhibited a Cu2+-induced increase in [Ca2+]i.These results suggest that Cu2+ activates eNOS through the mechanism of [Ca2+]i elevation due to Ca2+ influx into HPAEC and that the Cu2+-induced [Ca2+]i elevation in HPAEC is likely due to activation of the dihydropyridine-like receptors. PMID:9863645

  16. Biodynamics of copper oxide nanoparticles and copper ions in an oligochaete - Part I: Relative importance of water and sediment as exposure routes.

    PubMed

    Ramskov, Tina; Thit, Amalie; Croteau, Marie-Noële; Selck, Henriette

    2015-07-01

    Copper oxide (CuO) nanoparticles (NPs) are widely used, and likely released into the aquatic environment. Both aqueous (i.e., dissolved Cu) and particulate Cu can be taken up by organisms. However, how exposure routes influence the bioavailability and subsequent toxicity of Cu remains largely unknown. Here, we assess the importance of exposure routes (water and sediment) and Cu forms (aqueous and nanoparticulate) on Cu bioavailability and toxicity to the freshwater oligochaete, Lumbriculus variegatus, a head-down deposit-feeder. We characterize the bioaccumulation dynamics of Cu in L. variegatus across a range of exposure concentrations, covering both realistic and worst-case levels of Cu contamination in the environment. Both aqueous Cu (Cu-Aq; administered as Cu(NO3)2) and nanoparticulate Cu (CuO NPs), whether dispersed in artificial moderately hard freshwater or mixed into sediment, were weakly accumulated by L. variegatus. Once incorporated into tissues, Cu elimination was negligible, i.e., elimination rate constants were in general not different from zero for either exposure route or either Cu form. Toxicity was only observed after waterborne exposure to Cu-Aq at very high concentration (305μgL(-1)), where all worms died. There was no relationship between exposure route, Cu form or Cu exposure concentration on either worm survival or growth. Slow feeding rates and low Cu assimilation efficiency (approximately 30%) characterized the uptake of Cu from the sediment for both Cu forms. In nature, L. variegatus is potentially exposed to Cu via both water and sediment. However, sediment progressively becomes the predominant exposure route for Cu in L. variegatus as Cu partitioning to sediment increases.

  17. Evaluation of the behavior and movement of adult summer steelhead in the lower Cowlitz River, Washington, following collection and release, 2013-2014

    USGS Publications Warehouse

    Kock, Tobias J.; Liedtke, Theresa L.; Ekstrom, Brian K.; Gleizes, Chris; Dammers, Wolf

    2014-01-01

    Summer steelhead (Oncorhynchus mykiss) produced by a hatchery on the lower Cowlitz River, Washington, support a popular sport fishery during June–September each year. Many of these fish return to the Cowlitz Salmon Hatchery and are held until they are spawned in December. In the past, fishery managers have released some of the steelhead that return to the hatchery at downstream release sites (hereafter referred to as “recycled steelhead”) to increase angling opportunity. The recycling of summer steelhead is a potential use of hatchery fish that can benefit anglers in the lower Cowlitz River, provided these fish are harvested or return to the hatchery. However, recycled steelhead that are not removed from the river could compete against or spawn with wild winter steelhead, which would be a negative consequence of recycling. The Washington Department of Fish and Wildlife (WDFW) conducted an evaluation during 1998 and recycled 632 summer steelhead. They determined that 55 percent of the recycled steelhead returned to the hatchery and 15 percent of the fish were harvested by anglers. The remaining 30 percent of recycled fish were not known to have been removed from the river. Recycling has not occurred in recent years because definitive studies have not been conducted to determine the fate of the fish that remain in the lower Cowlitz River after being recycled. The U.S. Geological Survey and WDFW conducted a 2-year study during 2012–2014 to quantify recycled steelhead that (1) returned to the hatchery, (2) were captured by anglers, or (3) remained in the river. All recycled steelhead were marked with a Floy® tag and opercle punch, and 20 percent of the recycled fish were radio-tagged to determine post-release behavior and movement patterns, and to describe locations of tagged fish that remained in the river during the spawning period. During 2012–2013, we recycled 549 steelhead and determined that 50 percent of the fish returned to the hatchery, 18 percent

  18. A novel risperidone-loaded SAIB-PLGA mixture matrix depot with a reduced burst release: effects of solvents and PLGA on drug release behaviors in vitro/in vivo.

    PubMed

    Lin, Xia; Yang, Shenshen; Gou, Jingxin; Zhao, Mingming; Zhang, Yu; Qi, Na; He, Haibing; Cai, Cuifang; Tang, Xing; Guo, Penghong

    2012-02-01

    The purpose of this study was to develop an in situ forming SAIB (sucrose acetate isobutyrate)-PLGA (poly (d, lactide-co-glycolide)) mixture matrix depot for sustained release of risperidone. The factors affecting the risperidone release kinetics were investigated to obtain further insight into the drug release mechanisms. The burst release in vitro was significantly reduced (4.95%) by using DMSO as solvent. And, increasing the PLGA content from 2 to 10% w/w decreased the initial release from 6.95 to 1.05%. The initial release in vivo decreased with increasing PLGA content (2.0% w/w PLGA, C(max) = 1161.7 ± 550.2 ng ml(-1); 10% w/w PLGA, C(max) = 280.3 ± 98.5 ng ml(-1)). The persistence (AUC(4-20 days)) over 20 days increased from 76.8 ± 20.7 to 362.8 ± 75.0 ng d ml(-1) by inclusion of 10% PLGA compared with the PLGA-free depot. These results demonstrate that the SAIB-PLGA mixture matrix depot could be useful as a sustained delivery system for risperidone.

  19. Encapsulation of R. planticola Rs-2 from alginate-starch-bentonite and its controlled release and swelling behavior under simulated soil conditions.

    PubMed

    Wu, Zhansheng; Guo, Lina; Qin, Shaohua; Li, Chun

    2012-02-01

    The plant growth-promoting bacteria (PGPR) Raoultella planticola Rs-2 was encapsulated with the various blends of alginate, starch, and bentonite for development of controlled-release formulations. The stability and release characteristics of these different capsule formulations were evaluated. The entrapment efficiency of Rs-2 in the beads (capsules) was more than 99%. The diameter of dry beads ranged from 0.98 to 1.41 mm. The bacteria release efficiency, swelling ratio, and biodegradability of the different bead formulations were enhanced by increasing the starch or alginate contents, but were impeded by higher bentonite content. The release kinetics of viable cells from capsules and the swelling ratio of capsules were studied in simulated soil media of varying temperature, moisture, pH, and salt content. The release of loaded Rs-2 cells and swelling of capsules are greatly affected by moisture, temperature, pH and salt content of the release medium. The release of viable Rs-2 cells from capsules was positively associated with the swelling properties of the capsules. The release of Rs-2 cells occurred through a Case II diffusion mechanism. In summary, this work indicates that alginate-starch-bentonite blends are a viable option for the development of efficient controlled-release formulations of Rs-2 biofertilizer, and which could have a promising application in natural field conditions.

  20. Copper ion sensing with fluorescent electrospun nanofibers.

    PubMed

    Ongun, Merve Zeyrek; Ertekin, Kadriye; Gocmenturk, Mustafa; Ergun, Yavuz; Suslu, Aslıhan

    2012-05-01

    In this work, the use of electrospun nanofibrous materials as highly responsive fluorescence quenching-based copper sensitive chemosensor is reported. Poly(methyl methacrylate) and ethyl cellulose were used as polymeric support materials. Sensing slides were fabricated by electrospinning technique. Copper sensors based on the change in the fluorescence signal intensity of fluoroionophore; N'-3-(4-(dimethylamino phenly)allylidene)isonicotinohydrazide. The sensor slides exhibited high sensitivities due to the high surface area of the nanofibrous membrane structures. The preliminary results of Stern-Volmer analysis show that the sensitivities of electrospun nanofibrous membranes to detect Cu(II) ions are 6-20-fold higher than those of the continuous thin films. By this way we obtained linear calibration plots for Cu(II) ions in the concentration range of 10(-12)-10(-5)M. The response times of the sensing slides were less than 1 min. Stability of the employed ionophore in the matrix materials was excellent and when stored in the ambient air of the laboratory there was no significant drift in signal intensity after 6 months. Our stability tests are still in progress.

  1. Copper ion sensing with fluorescent electrospun nanofibers

    NASA Astrophysics Data System (ADS)

    Ongun, Merve Zeyrek; Ertekin, Kadriye; Gocmenturk, Mustafa; Ergun, Yavuz; Suslu, Aslıhan

    2012-05-01

    In this work, the use of electrospun nanofibrous materials as highly responsive fluorescence quenching-based copper sensitive chemosensor is reported. Poly(methyl methacrylate) and ethyl cellulose were used as polymeric support materials. Sensing slides were fabricated by electrospinning technique. Copper sensors based on the change in the fluorescence signal intensity of fluoroionophore; N'-3-(4-(dimethylamino phenly)allylidene)isonicotinohydrazide. The sensor slides exhibited high sensitivities due to the high surface area of the nanofibrous membrane structures. The preliminary results of Stern-Volmer analysis show that the sensitivities of electrospun nanofibrous membranes to detect Cu(II) ions are 6-20-fold higher than those of the continuous thin films. By this way we obtained linear calibration plots for Cu(II) ions in the concentration range of 10-12-10-5 M. The response times of the sensing slides were less than 1 min. Stability of the employed ionophore in the matrix materials was excellent and when stored in the ambient air of the laboratory there was no significant drift in signal intensity after 6 months. Our stability tests are still in progress.

  2. Regulating drug release behavior and kinetics from matrix tablets based on fine particle-sized ethyl cellulose ether derivatives: an in vitro and in vivo evaluation.

    PubMed

    Shah, Kifayat Ullah; Khan, Gul Majid

    2012-01-01

    The design and fabrication of sustained/controlled release dosage forms, employing new excipients capable of extending/controlling the release of drugs from the dosage forms over prolonged periods, has worked well in achieving optimally enhanced therapeutic levels of the drugs. In this sense, the objective of this study was to investigate the suitability of selected cellulose ether derivatives for use in direct compression (DC) and as efficient drug release controlling agents. Controlled release matrix tablets of ciprofloxacin were prepared at different drug-to-polymer (D : P) ratios by direct compression using a fine particle sized ethylcellulose ether derivative (ETHOCEL Standard Premium 7FP) as rate controlling polymer. The tablets obtained were evaluated for various physico-chemical characteristics and in-vitro drug release studies were conducted in phosphate buffer (pH 7.4) using PharmaTest dissolution apparatus at constant temperature of 37 °C ± 0.1. Similarity factor f(2) was employed to the release profiles of test formulations and were compared with marketed ciprofloxacin conventional tablets. Drug release mechanism and the kinetics involved were investigated by fitting the release profile data to various kinetic models. It was found that with increasing the proportion of ethylcellulose ether derivative in the matrix, the drug release was significantly extended up to 24 hours. The tablets exhibited zero order or nearly zero order drug transport mechanism. In vivo drug release performance of the developed controlled release tablets and reference conventional tablets containing ciprofloxacin were determined in rabbit serum according to randomized two-way crossover study design using High Performance Liquid Chromatography. Several bioavailability parameters of both the test tablets and conventional tablets including C(max⁡), T(max⁡) and AUC(0-t) were compared which showed an optimized C(max⁡) and T(max⁡) (P < 0.05). A good correlation was obtained

  3. Overexpression of the growth-hormone-releasing hormone gene in acromegaly-associated pituitary tumors. An event associated with neoplastic progression and aggressive behavior.

    PubMed Central

    Thapar, K.; Kovacs, K.; Stefaneanu, L.; Scheithauer, B.; Killinger, D. W.; Lioyd, R. V.; Smyth, H. S.; Barr, A.; Thorner, M. O.; Gaylinn, B.; Laws, E. R.

    1997-01-01

    The clinical behavior of growth hormone (GH)-producing pituitary tumors is known to vary greatly; however, the events underlying this variability remain poorly understood. Herein we demonstrate that tumor overexpression of the GH-releasing hormone (GHRH) gene is one prognostically informative event associated with the clinical aggressiveness of somatotroph pituitary tumors. Accumulation of GHRH mRNA transcripts was demonstrated in 91 of a consecutive series of 100 somatotroph tumors by in situ hybridization; these findings were corroborated by Northern analysis and reverse transcriptase polymerase chain reaction, and protein translation was confirmed by Western blotting. By comparison, transcript accumulation was absent or negligibly low in 30 normal pituitary glands. GHRH transcripts were found to preferentially accumulate among clinically aggressive tumors. Specifically, GHRH mRNA signal intensity was 1) linearly correlated with Ki-67 tumor growth fractions (r = 0.71; P < 0.001), 2) linearly correlated with preoperative serum GH levels (r = 0.56; p = 0.01), 3) higher among invasive tumors (P < 0.001), and 4) highest in those tumors in which post-operative remission was not achieved (P < 0.001). Using multivariate logistic regression, a model of postoperative remission likelihood was derived wherein remission was defined by the single criterion of suppressibility of GH levels to less than 2 ng/ml during an oral glucose tolerance test. In this outcome model, GHRH mRNA signal intensity proved to be the most important explanatory variable overall, eclipsing any and all conventional clinicopathological predictors as the single most significant predictor of postoperative remission; increases in GHRH mRNA signal were associated with marked declines in remission likelihood. The generalizability of this outcome model was further validated by the model's significant performance in predicting postoperative remission in a random sample of 30 somatotroph tumors treated at

  4. Functional antagonism between nociceptin/orphanin FQ and corticotropin-releasing factor in rat anxiety-related behaviors: involvement of the serotonergic system.

    PubMed

    Filaferro, M; Ruggieri, V; Novi, C; Calò, G; Cifani, C; Micioni Di Bonaventura, M V; Sandrini, M; Vitale, G

    2014-08-01

    Nociceptin/orphanin FQ (N/OFQ) acts as an anxiolytic-like agent in the rat and behaves as a functional antagonist of corticotropin-releasing factor (CRF) due to its ability to oppose CRF biological actions. In response to stress, CRF triggers changes in neurotransmitter systems including serotonin (5-HT). The role of 5-HT1A receptor in anxiety has been supported by preclinical and clinical studies. The present study investigated the possible functional antagonism between N/OFQ (1nmol/rat) and CRF (0.2nmol/rat) in anxiety-related conditions in rats, using elevated plus maze and defensive burying tests, in order to confirm previous literature results. Moreover, possible changes in the serotonergic system were studied in areas rich of serotonergic neurons: frontal cortex and pons. In both tests N/OFQ showed anxiolytic-like effects while CRF displayed anxiogenic-like effects. N/OFQ before CRF treatment counteracted the anxiogenic-like effects evoked by CRF. In frontal cortex, N/OFQ significantly decreased 5-HT levels but did not modify the hydroxyindoleacetic acid (5-HIAA) ones; CRF modified neither 5-HT nor 5-HIAA content but counteracted changes induced by N/OFQ alone. In pons, N/OFQ induced no change in serotonergic activity while CRF significantly decreased 5-HT levels and increased 5-HIAA content. The two peptides' combination reinstated serotonergic parameters to controls. In frontal cortex, N/OFQ increased the 5HT1A receptor density but reduced its affinity, while CRF alone did not induce any change. In pons, CRF decreased 5HT1ABmax and KD whereas N/OFQ was ineffective. All biochemical modifications were reverted by N/OFQ plus CRF treatment. The present study confirms that N/OFQ counteracts CRF anxiogenic-like effects in the behavioral tests evaluated. These effects may involve central serotonergic mechanisms since N/OFQ plus CRF induces a reversion of serotonergic changes provoked by single peptide. Our data support the hypothesis that N/OFQ may behave as

  5. THE EFFECT OF A SLOW-RELEASE FORMULATION OF ZUCLOPENTHIXOL ACETATE (ACUNIL®) ON CAPTIVE BLUE WILDEBEEST (CONNOCHAETES TAURINUS) BEHAVIOR AND PHYSIOLOGICAL RESPONSE.

    PubMed

    Laubscher, Liesel L; Hoffman, Louwrens C; Pitts, Neville I; Raath, Jacobus P

    2016-06-01

    The study investigated the effect of a slow-release formulation of zuclopenthixol acetate (Acunil®) on blue wildebeest ( Connochaetes taurinus ) in captivity. Two groups of trials were conducted using either Acunil or a placebo (control). Animals (Acunil: n = 17; placebo: n = 12) were observed for a 12-hr period before the administration of Acunil or the placebo (pretreatment). After 24 hr, animals were administered Acunil (1.5 mg/kg) or a placebo (1.0-3.0 ml of sterile water) and observed again for 12 hr (posttreatment). During both treatments, animals were stimulated every 2 hr for 1 min by a person entering the enclosure (referred to as periods of stimulation). Behavioral observations and continuous heart rate, respiration rate, and motion measurements were taken throughout. Animals treated with Acunil spent more time lying with their heads folded back, eating and standing with their heads down, and less time being vigilant and exploring while walking around. Animals treated with the placebo also spent less time being vigilant and more time lying with heads up. Animals treated with Acunil groomed less while standing and performed less head shaking; no such changes were observed in the control group. Neither Acunil nor the placebo had any effect (P > 0.05) on heart rate. However, overall mean respiration rate was lowered (P = 0.02) when animals were treated with Acunil (pretreatment: 14.5 ± 0.82 breaths/min; posttreatment: 12.5 ± 0.83 breaths/min). Acunil also caused a lowered (P < 0.05) respiration rate during periods when animals were stimulated (pretreatment: 16.2 ± 0.87 breaths/min; posttreatment: 13.7 ± 0.87 breaths/min) and when animals were trotting and being vigilant. No such changes were observed with the placebo. Both placebo- and Acunil-treated animals spent more time being stationary during periods of stimulation. However, Acunil-treated animals also spent less time moving fast when they were stimulated.

  6. Adsorption-desorption behavior of 2,4-D on NCP-modified bentonite and zeolite: implications for slow-release herbicide formulations.

    PubMed

    Bakhtiary, Somayeh; Shirvani, Mehran; Shariatmadari, Hossein

    2013-01-01

    Clay minerals have obtained considerable attention for slow-release formulation of herbicides to increase weed control efficacy and reduce leaching potential and environmental pollution. This study deals with preparing, characterizing and examining the potentials of modified bentonite and zeoilite in adsorption and release of 2,4-dichlorophenoxyacetic acid (2,4-D) herbicide. 2,4-D sorption of the N-cetylpyridinium (NCP)-modified bentonites and zeolites were much higher than those of unmodified substrates. The 2,4-D adsorption capacity of the organo-minerals increased with increasing surfactant loading. Desorption isotherms of 2,4-D did not coincide their corresponding sorption isotherms showing hysteresis. The proportion of 2,4-D released from the organo-minerals after seven desorption cycles varied between 29% and 50% of the total retained herbicide. The sorbed 2,4-D on the adsorbents showed gradual release pattern with time. The release pattern of 2,4-D from NCP-modified bentonite and zeolite, make these synthetic organo-minerals suitable candidate for slow release formulation of 2,4-D.

  7. Effect of HPMC and mannitol on drug release and bioadhesion behavior of buccal discs of buspirone hydrochloride: In-vitro and in-vivo pharmacokinetic studies

    PubMed Central

    Jaipal, A.; Pandey, M.M.; Charde, S.Y.; Raut, P.P.; Prasanth, K.V.; Prasad, R.G.

    2014-01-01

    Delivery of orally compromised therapeutic drug molecules to the systemic circulation via buccal route has gained a significant interest in recent past. Bioadhesive polymers play a major role in designing such buccal dosage forms, as they help in adhesion of designed delivery system to mucosal membrane and also prolong release of drug from delivery system. In the present study, HPMC (release retarding polymer) and mannitol (diluent and pore former) were used to prepare bioadhesive and controlled release buccal discs of buspirone hydrochloride (BS) by direct compression method. Compatibility of BS with various excipients used during the study was assessed using DSC and FTIR techniques. Effect of mannitol and HPMC on drug release and bioadhesive strength was studied using a 32 factorial design. The drug release rate from delivery system decreased with increasing levels of HPMC in formulations. However, bioadhesive strength of formulations increased with increasing proportion of HPMC in buccal discs. Increased levels of mannitol resulted in faster rate of drug release and rapid in vitro uptake of water due to the formation of channels in the matrix. Pharmacokinetic studies of designed bioadhesive buccal discs in rabbits demonstrated a 10-fold increase in bioavailability in comparison with oral bioavailability of buspirone reported. PMID:26106280

  8. Stimulus-responsiveness and methyl violet release behaviors of poly(NIPAAm-co-AA) hydrogels chemically crosslinked with β-cyclodextrin polymer bearing methacrylates.

    PubMed

    Zhao, Hui; Gao, Jun; Liu, Ruina; Zhao, Sanping

    2016-06-16

    To fabricate thermo- and pH-sensitive hydrogels functionalized with β-cyclodextrin (β-CD) moieties, β-CD polymer bearing methacrylate (CDP-g-GMA) used as a reactive and functional crosslinker was synthesized, and then copolymerized with N-isopropylacrylamide (NIPAAm) and acrylic acid (AA) in aqueous solution via UV-initiated free radical polymerization. The stimulus-responsiveness of the resultant hydrogels has been carried out by measuring the swelling ratio at different temperatures and pH values. The results showed that the thermo- and pH-sensitivities of the produced hydrogels were significantly dependent on the compositions of the hydrogels, and the dual sensitivities exhibited good reversible process. The interior morphology observed by SEM exhibited that the pore size of the hydrogels could be tailored by pH of the local medium. Using a water-soluble cationic dye methyl violet (MV) as a model drug, MV loading and release profiles of the hydrogels as potential drug controlled release carriers were evaluated. The MV release rate from CD-functionalized hydrogels was much slower than that from the hydrogel without β-CDs at both pH 2.0 and pH 7.4. The release of MV from CD-functionalized hydrogels at pH 2.0 was faster than that at pH 7.4, the release kinetics of MV from the CD-functionalized hydrogels displayed a sustained release profile, and the release mechanism followed Fickian diffusion.

  9. In Vitro Inhibition of Histamine Release Behavior of Cetirizine Intercalated into Zn/Al- and Mg/Al-Layered Double Hydroxides

    PubMed Central

    Hussein-Al-Ali, Samer Hasan; Al-Qubaisi, Mothanna; Hussein, Mohd Zobir; Ismail, Maznah; Zainal, Zulkarnain; Hakim, Muhammad Nazrul

    2012-01-01

    The intercalation of cetirizine into two types of layered double hydroxides, Zn/Al and Mg/Al, has been investigated by the ion exchange method to form CTZAN and CTMAN nanocomposites, respectively. The basal spacing of the nanocomposites were expanded to 31.9 Å for CTZAN and 31.2 Å for CTMAN, suggesting that cetirizine anion was intercalated into Layered double hydroxides (LDHs) and arranged in a tilted bilayer fashion. A Fourier transform infrared spectroscopy (FTIR) study supported the formation of both the nanocomposites, and the intercalated cetirizine is thermally more stable than its counterpart in free state. The loading of cetirizine in the nanocomposite was estimated to be about 57.2% for CTZAN and 60.7% CTMAN. The cetirizine release from the nanocomposites show sustained release manner and the release rate of cetirizine from CTZAN and CTMAN nanocomposites at pH 7.4 is remarkably lower than that at pH 4.8, presumably due to the different release mechanism. The inhibition of histamine release from RBL2H3 cells by the free cetirizine is higher than the intercalated cetirizine both in CTZAN and CTMAN nanocomposites. The viability in human Chang liver cells at 1000 μg/mL for CTZAN and CTMAN nanocomposites are 74.5 and 91.9%, respectively. PMID:22754339

  10. In vitro inhibition of histamine release behavior of cetirizine intercalated into Zn/Al- and Mg/Al-layered double hydroxides.

    PubMed

    Hussein-Al-Ali, Samer Hasan; Al-Qubaisi, Mothanna; Hussein, Mohd Zobir; Ismail, Maznah; Zainal, Zulkarnain; Hakim, Muhammad Nazrul

    2012-01-01

    The intercalation of cetirizine into two types of layered double hydroxides, Zn/Al and Mg/Al, has been investigated by the ion exchange method to form CTZAN and CTMAN nanocomposites, respectively. The basal spacing of the nanocomposites were expanded to 31.9 Å for CTZAN and 31.2 Å for CTMAN, suggesting that cetirizine anion was intercalated into Layered double hydroxides (LDHs) and arranged in a tilted bilayer fashion. A Fourier transform infrared spectroscopy (FTIR) study supported the formation of both the nanocomposites, and the intercalated cetirizine is thermally more stable than its counterpart in free state. The loading of cetirizine in the nanocomposite was estimated to be about 57.2% for CTZAN and 60.7% CTMAN. The cetirizine release from the nanocomposites show sustained release manner and the release rate of cetirizine from CTZAN and CTMAN nanocomposites at pH 7.4 is remarkably lower than that at pH 4.8, presumably due to the different release mechanism. The inhibition of histamine release from RBL2H3 cells by the free cetirizine is higher than the intercalated cetirizine both in CTZAN and CTMAN nanocomposites. The viability in human Chang liver cells at 1000 μg/mL for CTZAN and CTMAN nanocomposites are 74.5 and 91.9%, respectively.

  11. Effects of Particle Hydrophobicity, Surface Charge, Media pH Value and Complexation with Human Serum Albumin on Drug Release Behavior of Mitoxantrone-Loaded Pullulan Nanoparticles

    PubMed Central

    Tao, Xiaojun; Jin, Shu; Wu, Dehong; Ling, Kai; Yuan, Liming; Lin, Pingfa; Xie, Yongchao; Yang, Xiaoping

    2015-01-01

    We prepared two types of cholesterol hydrophobically modified pullulan nanoparticles (CHP) and carboxyethyl hydrophobically modified pullulan nanoparticles (CHCP) substituted with various degrees of cholesterol, including 3.11, 6.03, 6.91 and 3.46 per polymer, and named CHP−3.11, CHP−6.03, CHP−6.91 and CHCP−3.46. Dynamic laser light scattering (DLS) showed that the pullulan nanoparticles were 80–120 nm depending on the degree of cholesterol substitution. The mean size of CHCP nanoparticles was about 160 nm, with zeta potential −19.9 mV, larger than CHP because of the carboxyethyl group. A greater degree of cholesterol substitution conferred greater nanoparticle hydrophobicity. Drug-loading efficiency depended on nanoparticle hydrophobicity, that is, nanoparticles with the greatest degree of cholesterol substitution (6.91) showed the most drug encapsulation efficiency (90.2%). The amount of drug loading increased and that of drug release decreased with enhanced nanoparticle hydrophobicity. Nanoparticle surface-negative charge disturbed the amount of drug loading and drug release, for an opposite effect relative to nanoparticle hydrophobicity. The drug release in pullulan nanoparticles was higher pH 4.0 than pH 6.8 media. However, the changed drug release amount was not larger for negative-surface nanoparticles than CHP nanoparticles in the acid release media. Drug release of pullulan nanoparticles was further slowed with human serum albumin complexation and was little affected by nanoparticle hydrophobicity and surface negative charge. PMID:28344259

  12. Syndactyly Release.

    PubMed

    Braun, Tara L; Trost, Jeffrey G; Pederson, William C

    2016-11-01

    Syndactyly is one of the most common congenital hand anomalies treated by pediatric plastic surgeons. Established principles of syndactyly separation dictate the timing and order of syndactyly release, with the goals of surgery being the creation of an anatomically normal webspace, tension-free closure of soft tissue, and return of function to the fingers. Numerous surgical methods have been described, many of which involve the use of local flaps to reconstruct the commissure and full-thickness skin grafts for coverage of raw areas. Recently, reconstructive techniques without the use of skin grafts have been devised, which work well for certain indications. Special considerations are described for complete, complex, and syndromic syndactylies. Outcomes for simple syndactyly release are typically good when surgical principles are followed, whereas complex syndactyly release tends to have less-favorable outcomes and more complications.

  13. Nanoencapsulation of a water soluble drug in biocompatible polyesters. Effect of polyesters melting point and glass transition temperature on drug release behavior.

    PubMed

    Karavelidis, Vassilios; Giliopoulos, Dimitrios; Karavas, Evangelos; Bikiaris, Dimitrios

    2010-12-23

    Five polyesters based on 1,3-propanediol or ethylene glycol and an aliphatic dicarboxylic acid were used for the preparation of Ropinirole HCl-loaded nanoparticles. The advantage of the present study is that the used polyesters - as well as poly(lactic acid) (PLA) - have similar degree of crystallinity but different melting points, varying from 46.7 to 166.4°C. Based on polymer toxicity on HUVEC, the biocompatibility of these aliphatic polyesters was found comparable to that of PLA and thus the studied polyesters could be used as drug carriers. Drug encapsulation in polyesters was performed via emulsification/solvent evaporation method. Particle size of drug-loaded nanoparticles was between 140 and 190 nm, as measured by light scattering. Drug loading content for all the polyesters varies between 10 and 16% and their entrapment efficiency is relatively high (32-48%). WAXD patterns of nanoparticles show that Ropinirole HCl lies in amorphous state within polymer matrices. Drug release diagrams reveal that the higher percentage of Ropinirole HCl is released during the first 6h after its insertion in the dissolution medium. Fast release rates of the drug are attributed to high hydrophilicity of Ropinirole HCl. Melting point (T(m)) and glass transition temperature (T(g)) of the host polymer matrices seem to be important parameters, since higher drug release rates are observed in polyesters with low T(m) and T(g).

  14. Release Behavior and Toxicity Profiles towards Leukemia (WEHI-3B) Cell Lines of 6-Mercaptopurine-PEG-Coated Magnetite Nanoparticles Delivery System

    PubMed Central

    Kura, Aminu Umar; Hussein-Al-Ali, Samer Hasan; Hussein, Mohd Zobir bin; Fakurazi, Sharida; Shaari, Abdul Halim; Ahmad, Zalinah

    2014-01-01

    The coating of an active drug, 6-mercaptopurine, into the iron oxide nanoparticles-polyethylene glycol (FNPs-PEG) in order to form a new nanocomposite, FPEGMP-2, was accomplished using coprecipitation technique. The resulting nanosized with a narrow size distribution magnetic polymeric particles show the superparamagnetic properties with 38.6 emu/g saturation magnetization at room temperature. Fourier transform infrared spectroscopy and the thermal analysis study supported the formation of the nanocomposite and the enhancement of thermal stability in the resulting nanocomposite comparing with its counterpart in free state. The loading of 6-mercaptopurine (MP) in the FPEGMP-2 nanocomposite was estimated to be about 5.6% and the kinetic experimental data properly correlated with the pseudo-second order model. Also, the release of MP from the FPEGMP-2 nanocomposite shows the sustained release manner which is remarkably lower in phosphate buffered solution at pH 7.4 than pH 4.8, due to different release mechanism. The maximum percentage release of MP from the nanocomposite reached about 60% and 97% within about 92 and 74 hours when exposed to pH 7.4 and 4.8, respectively. PMID:24895684

  15. In vitro drug release behavior, mechanism and antimicrobial activity of rifampicin loaded low molecular weight PLGA-PEG-PLGA triblock copolymeric nanospheres.

    PubMed

    Gajendiran, M; Divakar, S; Raaman, N; Balasubramanian, S

    2013-12-01

    Poly (lactic-co-glycolic acid) (PLGA (92:8)) and a series of PLGA-PEG-PLGA tri block copolymers were synthesized by direct melt polycondensation. The copolymers were characterized by FTIR, and 1HNMR spectroscopic techniques, viscosity, gel permeation chromatography (GPC) and powder x-ray diffraction (XRD). The rifampicin (RIF) loaded polymeric nanospheres (NPs) were prepared by ultrasonication-W/O emulsification technique. The NPs have been characterized by field emission scanning electron microscopy (FESEM), TEM, powder X-ray diffraction (XRD), UVvisible spectroscopy and DLS measurements. The drug loaded triblock copolymeric NPs have five folds higher drug content and drug loading efficiency than that of PLGA microspheres (MPs). The in vitro drug release study shows that the drug loaded NPs showed an initial burst release after that sustained release up to 72 h. All the triblock copolymeric NPs follow anomalous drug diffusion mechanism while the PLGA MPs follow non-Fickian super case-II mechanism up to 12 h. The overall in-vitro release follows second order polynomial kinetics up to 72 h. The antimicrobial activity of the RIF loaded polymer NPs was compared with that of pure RIF and tetracycline (TA). The RIF loaded triblock copolymeric NPs inhibited the bacterial growth more effectively than the pure RIF and TA.

  16. Origin of Long-Term Storage Stability and Nitric Oxide Release Behavior of CarboSil Polymer Doped with S-Nitroso-N-acetyl-D-penicillamine.

    PubMed

    Wo, Yaqi; Li, Zi; Brisbois, Elizabeth J; Colletta, Alessandro; Wu, Jianfeng; Major, Terry C; Xi, Chuanwu; Bartlett, Robert H; Matzger, Adam J; Meyerhoff, Mark E

    2015-10-14

    The prolonged and localized delivery of nitric oxide (NO), a potent antithrombotic and antimicrobial agent, has many potential biomedical applications. In this work, the origin of the long-term storage stability and sustained NO release mechanism of S-nitroso-N-acetyl-D-penicillamine (SNAP)-doped CarboSil 20 80A polymer, a biomedical thermoplastic silicone-polycarbonate-urethane, is explored. Long-term (22 days) localized NO release is achieved by utilizing a cross-linked silicone rubber as topcoats, which can greatly reduce the amount of SNAP, NAP, and NAP disulfide leaching from the SNAP-doped CarboSil films, as measured by LC-MS. Raman spectroscopy and powder X-ray diffraction characterization of SNAP-doped CarboSil films demonstrate that a polymer-crystal composite is formed during the solvent evaporation process when SNAP exceeds its solubility in CarboSil (ca. 3.4-4.0 wt %). Further, when exceeding this solubility threshold, SNAP exists in an orthorhombic crystal form within the bulk of the polymer. The proposed mechanism of sustained NO release in SNAP-doped CarboSil is that the solubilized SNAP in the polymer matrix decomposes and releases NO, primarily in the water-rich regions near the polymer/solution interface, and the dissolved SNAP in the bulk polymeric phase becomes unsaturated, resulting in the dissolution of crystalline SNAP within the bulk of the polymer. This is a very slow process that ultimately leads to NO release at the physiological flux levels for >3 weeks. The increased stability of SNAP within CarboSil is attributed to the intermolecular hydrogen bonds between the SNAP molecules that crystallize. This crystallization also plays a key role in maintaining RSNO stability within the CarboSil polymer for >8 months at 37 °C (88.5% remains). Further, intravascular catheters fabricated with this new material are demonstrated to significantly decrease the formation of Staphylococcus aureus biofilm (a leading cause of nosocomial bloodstream

  17. Origin of Long-Term Storage Stability and Nitric Oxide Release Behavior of CarboSil Polymer Doped with S-Nitroso-N-acetyl-d-penicillamine

    PubMed Central

    2016-01-01

    The prolonged and localized delivery of nitric oxide (NO), a potent antithrombotic and antimicrobial agent, has many potential biomedical applications. In this work, the origin of the long-term storage stability and sustained NO release mechanism of S-nitroso-N-acetyl-d-penicillamine (SNAP)-doped CarboSil 20 80A polymer, a biomedical thermoplastic silicone-polycarbonate-urethane, is explored. Long-term (22 days) localized NO release is achieved by utilizing a cross-linked silicone rubber as topcoats, which can greatly reduce the amount of SNAP, NAP, and NAP disulfide leaching from the SNAP-doped CarboSil films, as measured by LC–MS. Raman spectroscopy and powder X-ray diffraction characterization of SNAP-doped CarboSil films demonstrate that a polymer–crystal composite is formed during the solvent evaporation process when SNAP exceeds its solubility in CarboSil (ca. 3.4–4.0 wt %). Further, when exceeding this solubility threshold, SNAP exists in an orthorhombic crystal form within the bulk of the polymer. The proposed mechanism of sustained NO release in SNAP-doped CarboSil is that the solubilized SNAP in the polymer matrix decomposes and releases NO, primarily in the water-rich regions near the polymer/solution interface, and the dissolved SNAP in the bulk polymeric phase becomes unsaturated, resulting in the dissolution of crystalline SNAP within the bulk of the polymer. This is a very slow process that ultimately leads to NO release at the physiological flux levels for >3 weeks. The increased stability of SNAP within CarboSil is attributed to the intermolecular hydrogen bonds between the SNAP molecules that crystallize. This crystallization also plays a key role in maintaining RSNO stability within the CarboSil polymer for >8 months at 37 °C (88.5% remains). Further, intravascular catheters fabricated with this new material are demonstrated to significantly decrease the formation of Staphylococcus aureus biofilm (a leading cause of nosocomial bloodstream

  18. Toggle release

    NASA Technical Reports Server (NTRS)

    Graves, Thomas J. (Inventor); Yang, Robert A. (Inventor); Brown, Christopher W. (Inventor)

    1989-01-01

    A pyrotechnic actuated structural release device 10 which is mechanically two fault tolerant for release. The device 10 comprises a fastener plate 11 and fastener body 12, each attachable to a different one of a pair of structures to be joined. The fastener plate 11 and body 12 are fastenable by a toggle 13 supported at one end on the fastener plate and mounted for universal pivotal movement thereon. At its other end which is received in a central opening in the fastener body 12 and adapted for limited pivotal movement therein the toggle 13 is restrained by three retractable latching pins 61 symmetrically disposed in equiangular spacing about the axis of the toggle 13 and positionable in latching engagement with an end fitting on the toggle. Each pin 61 is individually retractable by combustion of a pyrotechnic charge 77, the expanding gases of which are applied to a pressure receiving face 67 on the latch pin 61 to effect its retraction from the toggle. While retraction of all three pins 62 releases the toggle, the fastener is mechanically two fault tolerant since the failure of any single one or pair of the latch pins to retract results in an asymmetrical loading on the toggle and its pivotal movement to effect a release. An annular bolt 18 is mounted on the fastener plate 11 as a support for the socket mounting 30, 37 of the toggle whereby its selective axial movement provides a means for preloading the toggle.

  19. Extracellular and circulating redox- and metalloregulated eRNA and eRNP: copper ion-structured RNA cytokines (angiotropin ribokines) and bioaptamer targets imparting RNA chaperone and novel biofunctions to S100-EF-hand and disease-associated proteins.

    PubMed

    Wissler, Josef H

    2004-06-01

    Bioassays for cellular differentiation and tissue morphogenesis were used to design methods for isolation of bioactive redox- and metalloregulated nucleic acids and copper ion complexes with proteins from extracellular, circulating, wound, and supernatant fluids of cultured cells. In extracellular biospheres, diversities of nucleic acids were found to be secreted by cells upon activation. They may reflect nucleic acid biolibraries with molecular imprints of cellular history. After removal of protein components, eRNA prototypes exuded by activated cells were sequenced. They are small, endogenous, highly modified and edited, redox- and metalloregulated 5'-end phosphorylated extracellular eRNA (approximately 2-200 bases) with cellular, enzymic, and bioaptamer functions. Fenton-type OH* radical redox reactions may form modified nucleotides in RNA as wobbles eRNA per se, or as copper ion-complex with protein (e.g., S100A12-EF-hand protein, angiotropin-related protein, calgranulin-C, hippocampal neurite differentiation factor) are shown to be bioactive in vivo and in vitro as cytokines (ribokines) and as nonmitogenic angiomorphogens for endothelial cell differentiation in the formation of organoid supracellular capillary structures. As bioaptamers, copper ion-structured eRNA imparts novel biofunctions to proteins that they do not have on their own. The origin of extracellular RNA and intermediate precursors (up to 500 bases) was traced to intracellular parent nucleic acids. Intermediate precursors with and without partial homology were found. This suggests that bioaptamers are not directly retranslatable gene products. Metalloregulated eRNA bioaptamer function was investigated by domains (e.g. 5'...CUG...3' hairpin loop) for folding, bioactivity, and binding of protein with copper, calcium, and alkali metal ion affinity. Vice versa, metalloregulated nucleic acid-binding domains (K3H, R3H) in proteins were identified. Interaction of protein and eRNA docking potentials

  20. Upper critical solution temperature behavior of cinnamic acid and polyethyleneimine mixture and its effect on temperature-dependent release of liposome.

    PubMed

    Guo, Huangying; Kim, Jin-Chul

    2015-10-15

    The mixture of polyethyleneimine (PEI) and cinnamic acid (CA) in HEPES buffer (pH 7.0) exhibited an upper critical solution temperature in the temperature range of 20-50 °C. CA would be electrostatically conjugated with PEI and the PEI-CA conjugate is thought to act as a thermo-sensitive polymer. On the optical microscope image of PEI/CA mixture, microparticles were found at 25 °C, disappeared when heated to 50 °C, and formed again upon cooling to 25 °C. PEI-CA conjugate was immobilized on the surface of egg phosphatidylcholine (EPC) liposome by adding PEI to the suspension of liposome incorporating CA. The size and the zeta potential of the liposome markedly increased by cooling the liposomal suspension from 50 °C to 20 °C. This could be ascribed to the cooling-induced self-assembling property of PEI-CA conjugate. The release profile of Rhodamine B base from liposome incorporating CA with PEI was investigated while the liposome suspension of 50 °C was exposed to the release medium of 20 °C, 30 °C, 40 °C and 50 °C. The release degree was higher at a lower temperature. When exposed to a lower temperature (20 °C, 30 °C, 40 °C), PEI-CA could be self-assembled and change its configuration on the surface of liposome, promoting the release from the liposome.

  1. Mesoporous calcium–silicon xerogels with mesopore size and pore volume influence hMSC behaviors by load and sustained release of rhBMP-2

    PubMed Central

    Song, Wenhua; Li, Xiangde; Qian, Jun; Lv, Guoyu; Yan, Yonggang; Su, Jiacan; Wei, Jie

    2015-01-01

    Mesoporous calcium–silicon xerogels with a pore size of 15 nm (MCS-15) and pore volume of 1.43 cm3/g were synthesized by using 1,3,5-mesitylene (TMB) as the pore-expanding agent. The MCS-15 exhibited good degradability with the weight loss of 50 wt% after soaking in Tris-HCl solution for 56 days, which was higher than the 30 wt% loss shown by mesoporous calcium–silicon xerogels with a pore size of 4 nm (MCS-4). The pore size and pore volume of MCS-15 had significant influences on load and release of recombinant human bone morphogenetic protein-2 (rhBMP-2). The MCS-15 had a higher capacity to encapsulate a large amount of rhBMP-2; it could adsorb 45 mg/g of rhBMP-2 in phosphate-buffered saline after 24 hours, which was more than twice that with MCS-4 (20 mg/g). Moreover, the MCS-15 system exhibited sustained release of rhBMP-2 as compared with MCS-4 system (showing a burst release). The MCS-15/rhBMP-2 system could promote the proliferation and differentiation of human mesenchymal stem cells, showing good cytocompatibility and bioactivity. The results indicated that MCS-15, with larger mesopore size and higher pore volume, might be a promising carrier for loading and sustained release of rhBMP-2, which could be used as bone repair material with built-in osteoinduction function in bone reconstruction. PMID:25784801

  2. 5'-Guanosine monophosphate mediated biocompatible porous hydrogel of β-FeOOH-viscoelastic behavior, loading, and release capabilities of freeze-dried gel.

    PubMed

    Kumar, Anil; Gupta, Sudhir Kumar

    2014-09-04

    The present manuscript reports the characterization, optimization of rheological properties, and loading and release capabilities of 5'-GMP mediated β-FeOOH hydrogel. Circular dichroism (CD) analysis indicates it to contain mainly the left-handed helix similar to that of Z-DNA. The highest viscosity (>300 cP) corresponds to the sample containing 2.5 × 10(-3) mol dm(-3) of 5'-GMP (SP2H). Field emission scanning electron microscope (FESEM) and transmission electron microscope (TEM) studies indicate the freeze-dried (FD) SP2H to be porous in nature, which is also supported by its high Brunauer-Emmett-Teller (BET) surface area of 226 m(2)/g as compared to that of SP3H (75 m(2)/g). Selected area electron diffraction (SAED) analysis and Raman spectroscopy show it to contain β-FeOOH phase. The FD SP2H exhibits the high swelling ratio (326%) and loading capacity for methylene blue (MB) dye. It displays a controlled and efficient release (>90%) for optimized [MB] (2.5 × 10(-4) mol dm(-3)) in 48 h. The low toxicity of as synthesized FD SP2H nanostructures against MDA-MB-231 (breast cancer cells) up to 100 μg/mL suggests its biocompatible nature. The high porosity, surface area, % swelling, and loading and release performance of the hydrogel indicate its potential for drug delivery and other biological applications.

  3. Chronic restraint stress causes anxiety- and depression-like behaviors, downregulates glucocorticoid receptor expression, and attenuates glutamate release induced by brain-derived neurotrophic factor in the prefrontal cortex.

    PubMed

    Chiba, Shuichi; Numakawa, Tadahiro; Ninomiya, Midori; Richards, Misty C; Wakabayashi, Chisato; Kunugi, Hiroshi

    2012-10-01

    Stress and the resulting increase in glucocorticoid levels have been implicated in the pathophysiology of depressive disorders. We investigated the effects of chronic restraint stress (CRS: 6 hours × 28 days) on anxiety- and depression-like behaviors in rats and on the possible changes in glucocorticoid receptor (GR) expression as well as brain-derived neurotrophic factor (BDNF)-dependent neural function in the prefrontal cortex (PFC). We observed significant reductions in body weight gain, food intake and sucrose preference from 1 week after the onset of CRS. In the 5th week of CRS, we conducted open-field (OFT), elevated plus-maze (EPM) and forced swim tests (FST). We observed a decrease in the number of entries into open arms during the EPM (anxiety-like behavior) and increased immobility during the FST (depression-like behavior). When the PFC was removed after CRS and subject to western blot analysis, the GR expression reduced compared with control, while the levels of BDNF and its receptors remained unchanged. Basal glutamate concentrations in PFC acute slice which were measured by high performance liquid chromatography were not influenced by CRS. However, BDNF-induced glutamate release was attenuated after CRS. These results suggest that reduced GR expression and altered BDNF function may be involved in chronic stress-induced anxiety--and depression-like behaviors.

  4. Drug release behaviors of a pH sensitive semi-interpenetrating polymer network hydrogel composed of poly(vinyl alcohol) and star poly[2-(dimethylamino)ethyl methacrylate].

    PubMed

    Wu, Wei; Liu, Jing; Cao, Shuqin; Tan, Hong; Li, Jianshu; Xu, Fujian; Zhang, Xiao

    2011-09-15

    A series of pH sensitive semi-interpenetrating polymer network (semi-IPN) structural hydrogels composed of poly(vinyl alcohol) (PVA) and 21-arm star poly[2-(dimethylamino)ethyl methacrylate] (star PDMAEMA) with different molecular weight were prepared. Riboflavin was used as a model drug to evaluate the drug loading capacities and drug release behaviors of the semi-IPN structural hydrogels. The molecular weight of the star PDMAEMA polymers was calculated by GPC, and the formation of semi-IPN structure was confirmed by FTIR and SEM. It was found that the molecular weight of star PDMAEMA has significant effect on the structure, swelling ratio and drug release behaviors of the semi-IPN hydrogel at different pH conditions. The results suggested that the PVA/star PDMAEMA-50,000 hydrogel exhibited highest swelling ratio and drug loading capacity. The pH-sensitive semi-IPN hydrogel based on star PDMAEMA could be a promising drug delivery system due to the controllable porous structure.

  5. Vector-mediated release of GABA attenuates pain-related behaviors and reduces NaV1.7 in DRG neurons

    PubMed Central

    Chattopadhyay, Munmun; Mata, Marina; Fink, David J.

    2012-01-01

    Pain is a common and debilitating accompaniment of neuropathy that occurs as a complication of diabetes. In the current study, we examined the effect of continuous release of gamma amino butyric acid (GABA), achieved by gene transfer of glutamic acid decarboxylase (GAD67) to dorsal root ganglia (DRG) in vivo using a nonreplicating herpes simplex virus (HSV)-based vector (vG) in a rat model of painful diabetic neuropathy (PDN). Subcutaneous inoculation of vG reduced mechanical hyperalgesia, thermal hyperalgesia and cold allodynia in rats with PDN. Continuous release of GABA from vector transduced cells in vivo prevented the increase in the voltage gated sodium channel isoform 1.7 (NaV1.7) protein that is characteristic of PDN. In vitro, infection of primary DRG neurons with vG prevented the increase in NaV1.7 resulting from exposure to hyperglycemia. The effect of vector-mediated GABA on NaV1.7 levels in vitro was blocked by phaclofen but not by bicuculline, a GABAB receptor effect that was blocked by pertussis toxin-(PTX) interference with Gα(i/o) function. Taken in conjunction with our previous observation that continuous activation of delta opioid receptors by vector-mediated release of enkephalin also prevents the increase in NaV1.7 in DRG exposed to hyperglycemia in vitro or in vivo, the observations in this report suggest a novel common mechanism through which activation of G protein coupled receptors (GPCR) in DRG neurons regulate the phenotype of the primary afferent. PMID:21486703

  6. Dopamine release via the vacuolar ATPase V0 sector c-subunit, confirmed in N18 neuroblastoma cells, results in behavioral recovery in hemiparkinsonian mice.

    PubMed

    Jin, Duo; Muramatsu, Shin-Ichi; Shimizu, Nobuaki; Yokoyama, Shigeru; Hirai, Hirokazu; Yamada, Kiyofumi; Liu, Hong-Xiang; Higashida, Chiharu; Hashii, Minako; Higashida, Akihiko; Asano, Masahide; Ohkuma, Shoji; Higashida, Haruhiro

    2012-11-01

    A 16-kDa proteolipid, mediatophore, in Torpedo electric organs mediates Ca(2+)-dependent acetylcholine release. Mediatophore is identical to the pore-forming stalk c-subunit of the V0 sector of vacuolar proton ATPase (ATP6V0C). The function of ATP6V0C in the mammalian central nervous system is not clear. Here, we report transfection of adeno-associated viral vectors harboring rat ATP6V0C into the mouse substantia nigra, in which high potassium stimulation increased overflow of endogenous dopamine (DA) measured in the striatum by in vivo microdialysis. Next, in the striatum of 6-hydroxydopamine-lesioned mice, a model of Parkinson's disease (PD), human tyrosine hydroxylase, aromatic l-amino-acid decarboxylase and guanosine triphosphate cyclohydrolase 1, together with or without ATP6V0C, were expressed in the caudoputamen for rescue. Motor performance on the accelerating rotarod test and amphetamine-induced ipsilateral rotation were improved in the rescued mice coexpressing ATP6V0C. [(3)H]DA, taken up into cultured N18 neuronal tumor cells transformed to express ATP6V0C, was released by potassium stimulation. These results indicated that ATP6V0C mediates DA release from nerve terminals in the striatum of DA neurons of normal mice and from gene-transferred striatal cells of parkinsonian mice. The results suggested that ATP6V0C may be useful as a rescue molecule in addition to DA-synthetic enzymes in the gene therapy of PD.

  7. Drug release behavior of poly (lactic-glycolic acid) grafting from sodium alginate (ALG-g-PLGA) prepared by direct polycondensation.

    PubMed

    Shi, Gang; Ding, Yuanyuan; Zhang, Xin; Wu, Luyan; He, Fei; Ni, Caihua

    2015-01-01

    Hydrophobically modified sodium alginate, poly (lactic-glycolic acid) grafting from sodium alginate (ALG-g-PLGA), was successfully synthesized through direct one-step polymerization of sodium alginate, glycolic acid, and lactic acid. ALG-g-PLGA self-assembled to colloidal nanoparticles and subsequently hydrogel microspheres were obtained by crosslinking ALG-g-PLGA nanoparticles in the solution of calcium chloride. The modified hydrogel microspheres could be used as the drug delivery vehicles for a hydrophobic ibuprofen. Compared with sodium alginate, ALG-g-PLGA demonstrated an improved drug loading rate, encapsulation efficiency, and prolonged release speed. The products, as novel and highly promising biomaterials, have potential applications.

  8. Formulation, characterization and evaluation of the effect of polymer concentration on the release behavior of insulin-loaded Eudragit®-entrapped mucoadhesive microspheres

    PubMed Central

    Kenechukwu, Franklin C.; Momoh, Mumuni A.

    2016-01-01

    Introduction: The aim of this study was to use Eudragit® RL 100 (pH-independent polymer) and magnesium stearate (a hydrophobic droplet stabilizer) in combination to improve the controlled release effect of insulin-loaded Eudragit® entrapped microspheres prepared by the emulsification-coacervation technique. Materials and Methods: Mucoadhesive insulin-loaded microspheres containing magnesium stearate and varying proportions of Eudragit® RL 100 were prepared by the emulsification-coacervation technique and evaluated for thermal properties, physicochemical performance, and in vitro dissolution in acidic and subsequently basic media. Results: Stable, spherical, brownish, discrete, free-flowing and mucoadhesive insulin-loaded microspheres with size range of 14.20 ± 0.30-19.80 ± 0.60 μm and loading efficiency of 74.55 ± 1.05-75.90 ± 1.94% were formed. After 3 h, microspheres prepared with insulin: Eudragit® RL 100 ratios of 1:4, 1:6, and 1:8 released 73.40 ± 1.38, 66.20 ± 1.59, and 71.30 ± 1.27 (%) of insulin, respectively. Conclusion: The physicochemical and physico-technical properties of the microspheres developed in this study demonstrated the effectiveness of the Eudragit® RL entrapped mucoadhesive microspheres (prepared by the emulsification-coacervation technique using varying polymer concentration) as a carrier system for oral insulin delivery. PMID:27051626

  9. A mark release-recapture study to define the flight behaviors of Anopheles vestitipennis and Anopheles albimanus in Belize, Central America.

    PubMed

    Achee, Nicole L; Grieco, John P; Andre, Richard G; Rejmankova, Eliska; Roberts, Donald R

    2007-09-01

    The recapture rates of wild-caught, unengorged Anopheles vestitipennis and Anopheles albimanus females were determined at 0, 400, and 800 m from a fixed release point in Belize, Central America. Three sampling trials, each consisting of two 12-hour collections, were performed at each distance during September-October 2003. A total of 1,621 An. vestitipennis and 1,326 An. albimanus were marked and released during the course of the study. The recapture rate of An. vestitipennis was greatest at 0 m (7.9%; 44/ 556) and declined from 3.0% (16/531) at 400 m to 0.2% (1/534) at 800 m. Anopheles albimanus females were recaptured only at the 0-m distance and in extremely low numbers (1.1%; 5/446). Biting patterns for the unmarked natural populations were similar to those previously described for Belize, and recaptures for both species occurred during these normal biting times. The overall recapture rates for An. vestitipennis (3.76%; 61/ 1,621) and An. albimanus (0.38%; 5/1,326) indicate that An. vestitipennis has a higher probability of being attracted to a human habitation.

  10. Biological Assessment of Triazine Dendrimers as Candidate Platforms for Nanomedicine: Toxicological Profiles, Solution Behavior, Biodistribution, and Drug Release and Efficacy in a PEGylated, Paclitaxel Construct

    PubMed Central

    Lo, Su-Tang; Stern, Stephan; Clogston, Jeffrey D.; Zheng, Jiwen; Adiseshaiah, Pavan P.; Dobrovolskaia, Marina; Lim, Jongdoo; Patri, Anil; Sun, Xiankai; Simanek, Eric E.

    2010-01-01

    The physicochemical characteristics, in vitro properties, and in vivo toxicity and efficacy of a third generation triazine dendrimer bearing approximately nine 2 kDa polyethylene glycol chains and twelve ester linked paclitaxel groups are reported. The hydrodynamic diameter of the neutral construct varies slightly with aqueous solvent ranging from 15.6–19.4 nm. Mass spectrometry and light scattering suggest radically different molecular weights with the former ~40 kDa mass consistent with expectation, and the latter 400 kDa mass consistent with a decameric structure and the observed hydrodynamic radii. HPLC can be used to assess purity as well as paclitaxel release, which is insignificant in organic solvents or aqueous solutions at neutral and low pH. Paclitaxel release occurs in vitro in human, rat, and mouse plasma and is non-linear, ranging from 7–20% cumulative release over a 48 hour incubation period. The construct is 2–3 orders of magnitude less toxic than Taxol® by weight in human hepatocarcinoma (Hep G2), porcine renal proximal tubule (LLC-PK1), and human colon carcinoma (LS174T) cells, but shows similar cytotoxicity to Abraxane® in LS174T cells. Both Taxol® and the construct appear to induce caspase 3-dependent apoptosis. The construct shows a low level of endotoxin, is not hemolytic and does not induce platelet aggregation in vitro, but does appear to reduce collagen-induced platelet aggregation in vitro. Furthermore, the dendrimer formulation slightly activates the complement system in vitro due most likely to the presence of trace amounts (<1%) of free paclitaxel. An animal study provided insight into the maximum tolerated dose (MTD) wherein 10, 25, 50 and 100 mg paclitaxel/kg of construct or Abraxane were administered once per week for three consecutive weeks to non-tumor bearing athymic nude mice. The construct showed in vivo toxicity comparable to Abraxane. Both formulations were found to be non-toxic at the administered doses, and the

  11. Fission product iodine during early Hanford-Site operations: Its production and behavior during fuel processing, off-gas treatment and release to the atmosphere

    SciTech Connect

    Burger, L.L.

    1991-05-01

    The Hanford Environmental Dose Reconstruction (HEDR) Project was established to estimate the radiological dose impact that Hanford Site operations may have made on the local and regional population. This impact is estimated by examining operations involving radioactive materials that were conducted at the Hanford Site from the startup of the first reactor in 1944 to the present. HEDR Project work is divided among several technical tasks. One of these tasks, Source Terms, is designed to develop quantitative estimates of all significant emissions of radionuclides by Hanford Site operations since 1944. Radiation doses can be estimated from these emissions by accounting for specific radionuclide transport conditions and population demography. This document provides technical information to assist in the evaluation of iodine releases. 115 refs., 5 figs., 3 tabs.

  12. Corticotropin-releasing Factor in the Rat Dorsal Raphe Nucleus Promotes Different Forms of Behavioral Flexibility Depending on Social Stress History

    PubMed Central

    Snyder, Kevin P; Hill-Smith, Tiffany E; Lucki, Irwin; Valentino, Rita J

    2015-01-01

    The stress-related neuropeptide, corticotropin-releasing factor (CRF) regulates the dorsal raphe nucleus–serotonin (DRN–5-HT) system during stress and this may underlie affective and cognitive dysfunctions that characterize stress-related psychiatric disorders. CRF acts on both CRF1 and CRF2 receptor subtypes in the DRN that exert opposing inhibitory and excitatory effects on DRN-5-HT neuronal activity and 5-HT forebrain release, respectively. The current study first assessed the cognitive effects of intra-DRN microinfusion of CRF or the selective CRF2 agonist, urocortin II in stress-naive rats on performance of an operant strategy set-shifting task that is mediated by the medial prefrontal cortex (mPFC). CRF (30 ng) facilitated strategy set-shifting performance, whereas higher doses of CRF and urocortin II that would interact with CRF2 were without effect, consistent with a CRF1-mediated action. This dose decreased 5-HT extracellular levels in the mPFC, further supporting a role for CRF1. The effects of CRF were then assessed in rats exposed to repeated social stress using the resident–intruder model. Repeated social stress shifted the CRF effect from facilitation of strategy set shifting to facilitation of reversal learning and this was most prominent in a subpopulation of rats that resist defeat. Notably, in this subpopulation of rats 5-HT neuronal responses to CRF have been demonstrated to shift from CRF1-mediated inhibition to CRF2-mediated excitation. Because 5-HT facilitates reversal learning, the present results suggest that stress-induced changes in the cellular effects of CRF in the DRN translate to changes in cognitive effects of CRF. Together, the results underscore the potential for stress history to shift cognitive processing through changes in CRF neurotransmission in the DRN and the association of this effect with coping strategy. PMID:25865931

  13. Three-dimensional Printed Scaffolds with Gelatin and Platelets Enhance In vitro Preosteoblast Growth Behavior and the Sustained-release Effect of Growth Factors

    PubMed Central

    Zhu, Wei; Xu, Chi; Ma, Bu-Peng; Zheng, Zhi-Bo; Li, Yu-Long; Ma, Qi; Wu, Guo-Liang; Weng, Xi-Sheng

    2016-01-01

    Background: Three-dimensional (3D) printing technology holds great promise for treating diseases or injuries that affect human bones with enhanced performance over traditional techniques. Different patterns of design can lead to various mechanical properties and biocompatibility to various degrees. However, there is still a long way to go before we can fully take advantage of 3D printing technologies. Methods: This study tailored 3D printed scaffolds with gelatin and platelets to maximize bone regeneration. The scaffolds were designed with special internal porous structures that can allow bone tissue and large molecules to infiltrate better into the scaffolds. They were then treated with gelatin and platelets via thermo-crosslinking and freeze-drying, respectively. Vascular endothelial growth factor (VEGF) and transforming growth factor (TGF)-β1 were measured at different time points after the scaffolds had been made. Cell proliferation and cytotoxicity were determined via cell counting kit-8 (CCK-8) assay. Results: There was a massive boost in the level of VEGF and TGF-β1 released by the scaffolds with gelatin and platelets compared to that of scaffolds with only gelatin. After 21 days of culture, the CCK-8 cell counts of the control group and treated group were significantly higher than that of the blank group (P < 0.05). The cytotoxicity test also indicated the safety of the scaffolds. Conclusions: Our experiments confirmed that the 3D printed scaffolds we had designed could provide a sustained-release effect for growth factors and improve the proliferation of preosteoblasts with little cytotoxicity in vitro. They may hold promise as bone graft substitute materials in the future. PMID:27779164

  14. Transport, retention, and long-term release behavior of ZnO nanoparticle aggregates in saturated quartz sand: Role of solution pH and biofilm coating.

    PubMed

    Han, Yosep; Hwang, Gukhwa; Kim, Donghyun; Bradford, Scott A; Lee, Byoungcheun; Eom, Igchun; Kim, Pil Je; Choi, Siyoung Q; Kim, Hyunjung

    2016-03-01

    The transport, retention, and long-term release of zinc oxide nanoparticle aggregates (denoted below as ZnO-NPs) were investigated in saturated, bare and biofilm (Pseudomonas putida) coated sand packed columns. Almost complete retention of ZnO-NPs occurred in bare and biofilm coated sand when the influent solution pH was 9 and the ionic strength (IS) was 0.1 or 10 mM NaCl, and the retention profiles were always hyper-exponential. Increasing the solution IS and biofilm coating produced enhanced retention of ZnO-NPs near the column inlet. The enhanced NPs retention at high IS was attributed to more favorable NP-silica and NP-NP interactions; this was consistent with the interaction energy calculations. Meanwhile, the greater NPs retention in the presence of biofilm was attributed to larger roughness heights which alter the mass transfer rate, the interaction energy profile, and lever arms associated with the torque balance; e.g., scanning electron and atomic force microscopy was used to determine roughness heights of 33.4 nm and 97.8 nm for bare sand and biofilm-coated sand, respectively. Interactions between NPs and extracellular polymeric substances may have also contributed to enhanced NP retention in biofilm-coated sand at low IS. The long-term release of retained ZnO-NPs was subsequently investigated by continuously injecting NP-free solution at pH 6, 9, or 10 and keeping the IS constant at 10 mM. The amount and rate of retained ZnO-NP removal was strongly dependent on the solution pH. Specifically, almost complete removal of retained ZnO-NPs was observed after 627 pore volumes when the solution pH was 6, whereas much less Zn was recovered when the eluting solution pH was buffered to pH = 9 and especially 10. This long-term removal was attributed to pH-dependent dissolution of retained ZnO-NPs because: (i) the solubility of ZnO-NPs increases with decreasing pH; and (ii) ZnO-NPs were not detected in the effluent. The presence of biofilm also decreased the

  15. An assessment of detection canine alerts using flowers that release methyl benzoate, the cocaine odorant, and an evaluation of their behavior in terms of the VOCs produced.

    PubMed

    Cerreta, Michelle M; Furton, Kenneth G

    2015-06-01

    In recent years, the high frequency of illicit substance abuse reported in the United States has made the development of efficient and rapid detection methods important. Biological detectors, such as canines (Canis familiaris), are valuable tools for rapid, on-site identification of illicit substances. However, research indicates that in many cases canines do not alert to the contraband, but rather to the volatile organic compounds (VOCs) that are released from the contraband, referred to as the "active odor." In 2013, canine accuracy and reliability were challenged in the Supreme Court case, State of Florida v. Jardines. In this case, it was stated that if a canine alerts to the active odor, and not the contraband, the canine's accuracy and selectivity could be questioned, since many of these compounds have been found in common household products. Specifically, methyl benzoate, the active odor of cocaine, has been found to be the most abundant compound produced by snapdragon flowers. Therefore, the purpose of this study is to evaluate the odor profiles of various species of snapdragon flowers to assess how significantly methyl benzoate contributes to the total VOC profile or fragrance that is produced. Particularly, this study examines the VOCs released from newly grown snapdragon flowers and determines its potential at eliciting a false alert from specially trained detection canines. The ability of detection canines to differentiate between cocaine and snapdragon flowers was determined in order to validate the field accuracy and discrimination power of these detectors. An optimized method using headspace solid-phase microextraction coupled with gas chromatography-mass spectrometry (HS-SPME/GC-MS) was used to test the different types and abundances of compounds generated from snapdragon flowers at various stages throughout the plants' life cycle. The results indicate that although methyl benzoate is present in the odor profile of snapdragon flowers, other

  16. Sexual Identity, Sex of Sexual Contacts, and Health-Risk Behaviors among Students in Grades 9-12--Youth Risk Behavior Surveillance, Selected Sites, United States, 2001-2009. Morbidity and Mortality Weekly Report. Early Release. Volume 60

    ERIC Educational Resources Information Center

    Kann, Laura; O'Malley Olsen, Emily; McManus, Tim; Kinchen, Steve; Chyen, David; Harris, William A.; Wechsler, Howell

    2011-01-01

    Problem: Sexual minority youths are youths who identify themselves as gay or lesbian, bisexual, or unsure of their sexual identity or youths who have only had sexual contact with persons of the same sex or with both sexes. Population-based data on the health-risk behaviors practiced by sexual minority youths are needed at the state and local…

  17. Contact: Releasing the news

    NASA Astrophysics Data System (ADS)

    Pinotti, Roberto

    The problem of mass behavior after man's future contacts with other intelligences in the universe is not only a challenge for social scientists and political leaders all over the world, but also a cultural time bomb as well. In fact, since the impact of CETI (Contact with Extraterrestrial Intelligence) on human civilization, with its different cultures, might cause a serious socio-anthropological shock, a common and predetermined worldwide strategy is necessary in releasing the news after the contact, in order to keep possible manifestations of fear, panic and hysteria under control. An analysis of past studies in this field and of parallel historical situations as analogs suggests a definite "authority crisis" in the public as a direct consequence of an unexpected release of the news, involving a devastating "chain reaction" process (from both the psychological and sociological viewpoints) of anomie and maybe the collapse of today's society. The only way to prevent all this is to prepare the world's public opinion concerning contact before releasing the news, and to develop a long-term strategy through the combined efforts of scientists, political leaders, intelligence agencies and the mass media, in order to create the cultural conditions in which a confrontation with ETI won't affect mankind in a traumatic way. Definite roles and tasks in this multi-level model are suggested.

  18. Role of a Genetic Polymorphism in the Corticotropin-Releasing Factor Receptor 1 Gene in Alcohol Drinking and Seeking Behaviors of Marchigian Sardinian Alcohol-Preferring Rats

    PubMed Central

    Ayanwuyi, Lydia O.; Carvajal, Francisca; Lerma-Cabrera, Jose M.; Domi, Esi; Björk, Karl; Ubaldi, Massimo; Heilig, Markus; Roberto, Marisa; Ciccocioppo, Roberto; Cippitelli, Andrea

    2013-01-01

    Marchigian Sardinian alcohol-preferring (msP) rats exhibit innate preference for alcohol, are highly sensitive to stress and stress-induced alcohol seeking. Genetic analysis showed that over-expression of the corticotropin-releasing factor (CRF) system of msP rats is correlated with the presence of two single nucleotide polymorphisms (SNPs) occurring in the promoter region (position −1836 and −2097) of the CRF1 receptor (CRF1-R) gene. Here we examined whether these point mutations were associated to the innate alcohol preference, stress-induced drinking, and seeking. We have recently re-derived the msP rats to obtain two distinct lines carrying the wild type (GG) and the point mutations (AA), respectively. The phenotypic characteristics of these two lines were compared with those of unselected Wistar rats. Both AA and GG rats showed similar patterns of voluntary alcohol intake and preference. Similarly, the pharmacological stressor yohimbine (0.0, 0.625, 1.25, and 2.5 mg/kg) elicited increased operant alcohol self-administration under fixed and progressive ratio reinforcement schedules in all three lines. Following extinction, yohimbine (0.0, 0.625, 1.25, and 2.5 mg/kg) significantly reinstated alcohol seeking in the three groups. However, at the highest dose this effect was no longer evident in AA rats. Treatment with the CRF1-R antagonist antalarmin (0, 5, 10, and 20 mg/kg) significantly reduced alcohol-reinforced lever pressing in the AA line (10 and 20 mg/kg) while a weaker or no effect was observed in the Wistar and the GG group, respectively. Finally, antalarmin significantly reduced yohimbine-induced increase in alcohol drinking in all three groups. In conclusion, these specific SNPs in the CRF1-R gene do not seem to play a primary role in the expression of the msP excessive drinking phenotype or stress-induced drinking but may be associated with a decreased threshold for stress-induced alcohol seeking and an increased sensitivity to the effects

  19. Corticotropin-releasing factor antagonist reduces activation of noradrenalin and serotonin neurons in the locus coeruleus and dorsal raphe in the arousal response accompanied by yawning behavior in rats.

    PubMed

    Kubota, Natsuko; Amemiya, Seiichiro; Motoki, Chiharu; Otsuka, Tomomi; Nishijima, Takeshi; Kita, Ichiro

    2012-04-01

    We previously reported that intracerebroventricular (icv) administration of corticotropin-releasing factor (CRF) antagonist attenuates the arousal response during yawning behavior in rats. However, the CRF-related pathway involved in the arousal response during yawning is still unclear. In the present study, we assessed the involvement of the CRF-containing pathway from the hypothalamic paraventricular nucleus (PVN) to the locus coeruleus (LC) and the dorsal raphe nucleus (DRN) in the arousal response during frequent spontaneous yawning, which was induced by several microinjections of l-glutamate into the PVN in anesthetized rats, using c-Fos immunohistochemistry. The PVN stimulation showed significant increases in activation of PVN CRF neurons, LC noradrenalin (NA) neurons and DRN serotonin (5-HT) neurons as well as arousal response during yawning. But icv administration of a CRF receptor antagonist, α-helical CRF (9-41), significantly inhibited the activation of both LC NA neurons and DRN 5-HT neurons except the activation of CRF neurons in the PVN, and significantly suppressed the arousal response during yawning. These results suggest that the CRF-containing pathway from PVN CRF neurons to LC NA neurons and DRN 5-HT neurons can be involved in the arousal response during yawning behavior.

  20. Blockade of P2X4 Receptors Inhibits Neuropathic Pain-Related Behavior by Preventing MMP-9 Activation and, Consequently, Pronociceptive Interleukin Release in a Rat Model

    PubMed Central

    Jurga, Agnieszka M.; Piotrowska, Anna; Makuch, Wioletta; Przewlocka, Barbara; Mika, Joanna

    2017-01-01

    Neuropathic pain is still an extremely important problem in today’s medicine because opioids, which are commonly used to reduce pain, have limited efficacy in this type of pathology. Therefore, complementary therapy is needed. Our experiments were performed in rats to evaluate the contribution of the purinergic system, especially P2X4 receptor (P2X4R), in the modulation of glia activation and, consequently, the levels of nociceptive interleukins after chronic constriction injury (CCI) of the right sciatic nerve, a rat model of neuropathic pain. Moreover, we studied how intrathecal (ith.) injection of a P2X4R antagonist Tricarbonyldichlororuthenium (II) dimer (CORM-2) modulates nociceptive transmission and opioid effectiveness in the CCI model. Our results demonstrate that repeated ith. administration of CORM-2 once daily (20 μg/5 μl, 16 and 1 h before CCI and then daily) for eight consecutive days significantly reduced pain-related behavior and activation of both spinal microglia and/or astroglia induced by CCI. Moreover, even a single administration of CORM-2 on day 7 after CCI attenuated mechanical and thermal hypersensitivity as efficiently as morphine and buprenorphine. In addition, using Western blot, we have shown that repeated ith. administration of CORM-2 lowers the CCI-elevated level of MMP-9 and pronociceptive interleukins (IL-1β, IL-18, IL-6) in the dorsal L4-L6 spinal cord and/or DRG. Furthermore, in parallel, CORM-2 upregulates spinal IL-1Ra; however, it does not influence other antinociceptive factors, IL-10 and IL-18BP. Additionally, based on our biochemical results, we hypothesize that p38MAPK, ERK1/2 and PI3K/Akt but not the NLRP3/Caspase-1 pathway are partly involved in the CORM-2 analgesic effects in rat neuropathic pain. Our data provide new evidence that P2X4R may indeed play a significant role in neuropathic pain development by modulating neuroimmune interactions in the spinal cord and DRG, suggesting that its blockade may have potential

  1. Attractant volatiles released by female and male Triatoma infestans (Hemiptera: Reduviidae), a vector of chagas disease: chemical analysis and behavioral bioassay.

    PubMed

    Fontan, Andrea; Audino, Paola Gonzalez; Martinez, Adriana; Alzogaray, Raul A; Zerb, Eduardo N; Camps, Francisco; Cork, Alan

    2002-01-01

    Volatiles emitted by male and female T infestans before and during copula were collected on Porapak-Q filters, desorbed with dichloromethane, and analyzed by gas chromotography and gas chromatography-mass spectrometry after confirmation of attractiveness in an arena bioassay. Chemical analysis confirmed the presence of (R,S) -2- and 3-methylbutan-1-ol in a 2:1 ratio; short chain acids (ethanoic to nonanoic acid); long chains acids decanoic to (Z)-9-octadecenoic acid; aliphatic aldehydes (hexanal to nonanal), benzaldehyde and dipropylsulphide from insects in copula. Electroantennographic studies conducted with a homologous series of aliphatic aldehydes on female and male T infestans showed that, for a given dose, EAG responses elicited from both sexes increased with increased chain length up to nonanal, after which EAG-activity declined. Attractiveness of non-acidic trace components identified in the volatiles were tested on male and female T. infestans, in an arena bioassay using a video tracking method. Aliphatic C6 to C10 aldehydes were tested: hexanal (1-100 microg) and heptanal (10 microg) were attractive to female T. infestans, high doses of octanal and nonanal (1-100 microg) were Unattractive to male and female T. infestans but low doses of nonanal (0.01-0.1 microg) were attractive to male T infestans. Benzaldehyde was highly attractive to female T. infestans at low doses (0.05- 0.1 microg). 3-methylbutan-1-ol was attractive to male T infestans at high dose (1,000 microg). (S) or (S,R) 2-methyl-butan-1-ol were attractive to males or females (1-1,000 microg). Blends of hexanal and benzaldehyde (20:1 and 40:1) showed an additive effect on attraction compared with hexanal alone, when tested on female T. infestans. The study has demonstrated the presence of a number of electrophysiologically and behaviorally active compounds in volatiles emitted by T. infestans in copula that may have a role in the postulated copulation pheromone.

  2. Early molecular and behavioral response to lipopolysaccharide in the WAG/Rij rat model of absence epilepsy and depressive-like behavior, involves interplay between AMPK, AKT/mTOR pathways and neuroinflammatory cytokine release.

    PubMed

    Russo, Emilio; Andreozzi, Francesco; Iuliano, Rodolfo; Dattilo, Vincenzo; Procopio, Teresa; Fiume, Giuseppe; Mimmi, Selena; Perrotti, Nicola; Citraro, Rita; Sesti, Giorgio; Constanti, Andrew; De Sarro, Giovambattista

    2014-11-01

    The mammalian target of rapamycin (mTOR) pathway has been recently indicated as a suitable drug target for the prevention of epileptogenesis. The mTOR pathway is known for its involvement in the control of the immune system. Since neuroinflammation is recognized as a major contributor to epileptogenesis, we wished to examine whether the neuroprotective effects of mTOR modulation could involve a suppression of the neuroinflammatory process in epileptic brain. We have investigated the early molecular mechanisms involved in the effects of intracerebral administration of the lipopolysaccharide (LPS) in the WAG/Rij rat model of absence epilepsy, in relation to seizure generation and depressive-like behavior; we also tested whether the effects of LPS could be modulated by treatment with rapamycin (RAP), a specific mTOR inhibitor. We determined, in specific rat brain areas, levels of p-mTOR/p-p70S6K and also p-AKT/p-AMPK as downstream or upstream indicators of mTOR activity and tested the effects of LPS and RAP co-administration. Changes in the brain levels of pro-inflammatory cytokines IL-1β and TNF-α and their relative mRNA expression levels were measured, and the involvement of nuclear factor-κB (NF-κB) was also examined in vitro. We confirmed that RAP inhibits the aggravation of absence seizures and depressive-like/sickness behavior induced by LPS in the WAG/Rij rats through the activation of mTOR and show that this effect is correlated with the ability of RAP to dampen and delay LPS increases in neuroinflammatory cytokines IL-1β and TNF-α, most likely through inhibition of the activation of NF-κB. Our results suggest that such a mechanism could contribute to the antiseizure, antiepileptogenic and behavioral effects of RAP and further highlight the potential therapeutic usefulness of mTOR inhibition in the management of human epilepsy and other neurological disorders. Furthermore, we show that LPS-dependent neuroinflammatory effects are also mediated by a

  3. The behavior and release of methane related to hydrates in a pockmark area in the eastern margin of the Japan Sea: An approach from chlorine isotope composition in pore water and sea water

    NASA Astrophysics Data System (ADS)

    Zhang, J.; Satake, H.; Takeuchi, A.; Gamo, T.

    2006-12-01

    Methane released from the seafloor is a strong contributor to the greenhouse gas budget. Some deposits of methane hydrates existing in ocean sediment are linked to plate collision/subduction boundaries and associated tectonic motion. Methane plumes were observed in the pockmark area off Sado, at the end of the eastern margin of the Japan Sea where the North American and Eurasian tectonic plates intersect. Our goal in this study is to investigate the origin of methane and its actual release mechanisms from the seafloor and its behavior and seasonal variation in the water column by using chemical oceanic observations and geochemical analysis of pore water and sea waters. Geochemical data sets are from five cruises over two years and three seasons. The KT05-11 and KT06-26 expeditions were on the R/V Tansei-Maru, NA220 on the T/S Nagasaki-Maru, and the NT05-10 and NT06-19 expeditions using the unmanned submersible HYPER-DOLPHIN and its mother-ship R/V Natsushima. Results of chlorine and oxygen isotope compositions and other water chemical characteristics indicate that methane hydrate is generated over the bottom and is then melted in the shallow water. The possible processes are: 1) In deep water, chlorine isotope composition shows inverse correlation with oxygen, which suggests the fine particles of methane hydrate are adhering to the surface of gas bubbles released from deep sediment together with cold seep; the methane hydrate particles possibly grow and expand above the bottom and rise in water column. 2) In shallower water mass (< 300m depth), the amount of fresh water accumulated hints that fresh water is derived from the melting of methane hydrate and contributes up to 3% of the amount calculated by the decrease in upper-water salinity; this implies that a corresponding amount of methane was transported to ocean surface. The seasonal variations of dissolved methane and other chemical features in shallow water are possibly affected by the methane-oxidation and

  4. The measurement of silver diffusivity in zirconium carbide to study the release behavior of 110mAg in the ZrC TRISO-coated nuclear fuel particle

    NASA Astrophysics Data System (ADS)

    Yang, Young-Ki; Allen, Todd R.

    2016-03-01

    The tri-structural isotropic (TRISO) coated particle fuel has been developed and used for high temperature gas-cooled reactors (HTGRs). It provides a unique robustness of the first barrier for the fission products. The TRISO fuel particle has typically consisted of a UO2 or UCO kernel, surrounded by successive layers of porous carbon, dense inner pyrocarbon, silicon carbide, and dense outer pyrocarbon. During operation, however, the SiC layer has been known to release radioactive silver 110mAg which makes maintenance more difficult and thus costly. Zirconium carbide has been considered as a promising alternative to the SiC fission product barrier. ZrC exhibits high temperature stability and possibly possesses superior Pd resistance, while the retention properties especially for silver have not been adequately studied. To help elucidate the diffusive behavior of silver in the ZrC coating of the TRISO-coated particle, a new diffusion experimental technique, called the encapsulating source method, has been developed by constructing a constant source diffusion couple between ZrC and Ag gas originated from Zr-Ag solid solution. Scanning electron microscopy (SEM), wavelength-dispersive X-ray spectroscopy (WDS), electron backscatter diffraction (EBSD) and optical methods were used to analyze the diffusion couple annealed at 1500 °C. The resultant diffusion coefficient of Ag in single-crystalline ZrC0.84 at 1500 °C was experimentally determined to be about 2.8 (±1.2) × 10-17 m2/s.

  5. Comprehensive copper ion hydration: experimental and theoretical investigation of Cu2+(H2O)n, Cu+(H2O)n, CuOH+(H2O)n

    NASA Astrophysics Data System (ADS)

    Sweeney, Andrew

    Guided ion beam tandem mass spectrometry is used to probe the kinetic energy dependence of both Cu2+(H2O)n, where n = 5--10, and CuOH+(H2O)n, where n = 0--4 colliding with Xe. The resulting cross sections are analyzed using statistical models to yield 0 K bond dissociation energies (BDEs). The primary dissociation pathway for Cu2+(H2O)n consists of water loss followed by the sequential loss of additional waters at higher energies until n = 7, at which point charge separation to form CuOH+(H2O) m + H+(H2O)n-m-2 is energetically favored. The primary dissociation pathway for CuOH+(H 2O)n is also water loss and is followed by the sequential loss of additional waters at higher energies until n = 1, at which point OH loss become competitive. The BDEs for loss of water and OH from CuOH +(H2O) are combined in a thermodynamic cycle with literature values to derive BDEs for the loss of OH from CuOH+(H 2O)n, where n = 0, 2--4. Infrared multiple photon dissociation (IRPD) spectroscopy is performed on CuOH+(H2O)n, where n = 2--9. These spectra are characterized through comparison to theoretical spectra of low energy isomers. It is found that CuOH+(H2O) n prefers a 4-coordinate inner shell, although contributions from 5-coordinate geometries cannot be ruled out in most cases and are clearly present for n = 7. This preference is found in the Cu2+(H2O) n system as well and differs from the Cu+(H2O) n system, which prefers a 2-coordinate inner shell. Electronic structure calculations are further employed to yield BDEs which agree reasonably well with experimental values. A method for modeling kinetic energy release distributions (KERD) on a guided ion beam tandem mass spectrometer is proposed. This method achieves reasonable agreement with dissociations occurring over loose transition states when reactants have little energy in excess of the dissociation threshold. Current limitations and future possibilities of this method are discussed in detail.

  6. Dual drug release from hydrogels covalently containing polymeric micelles that possess different drug release properties.

    PubMed

    Murata, Mari; Uchida, Yusuke; Takami, Taku; Ito, Tomoki; Anzai, Ryosuke; Sonotaki, Seiichi; Murakami, Yoshihiko

    2017-02-09

    In the present study, we designed hydrogels for dual drug release: the hydrogels that covalently contained the polymeric micelles that possess different drug release properties. The hydrogels that were formed from polymeric micelles possessing a tightly packed (i.e., well-entangled) inner core exhibited a higher storage modulus than the hydrogels that were formed from the polymeric micelles possessing a loosely packed structure. Furthermore, we conducted release experiments and fluorescent observations to evaluate the profiles depicting the release of two compounds, rhodamine B and auramine O, from either polymeric micelles or hydrogels. According to our results, (1) hydrogels that covalently contains polymeric micelles that possess different drug release properties successfully exhibit the independent release behaviors of the two compounds and (2) fluorescence microscopy can greatly facilitate efforts to evaluate drug release properties of materials.

  7. Delayed simultaneous release mechanism

    NASA Technical Reports Server (NTRS)

    Moyer, X. W.; Webb, J. B. (Inventor)

    1973-01-01

    The disclosed appendage release mechanism is particularly adapted for use with spacecraft operating with despin mechanisms and releasable appendages. It includes a flexible loop and a number of appendage releasing devices which are attached to the flexible loop. The appendage releasing devices are made up of piston-cams and ball latches which hold the appendages as long as the flexible loop is maintained in a taut condition, but which release the appendages upon relaxation of the flexible loop. The flexible loop remains taut as long as the despin weights remain attached, but relaxes when the despin weights are released.

  8. Morphology of Gas Release in Physical Simulants

    SciTech Connect

    Daniel, Richard C.; Burns, Carolyn A.; Crawford, Amanda D.; Hylden, Laura R.; Bryan, Samuel A.; MacFarlan, Paul J.; Gauglitz, Phillip A.

    2014-07-03

    This report documents testing activities conducted as part of the Deep Sludge Gas Release Event Project (DSGREP). The testing described in this report focused on evaluating the potential retention and release mechanisms of hydrogen bubbles in underground radioactive waste storage tanks at Hanford. The goal of the testing was to evaluate the rate, extent, and morphology of gas release events in simulant materials. Previous, undocumented scoping tests have evidenced dramatically different gas release behavior from simulants with similar physical properties. Specifically, previous gas release tests have evaluated the extent of release of 30 Pa kaolin and 30 Pa bentonite clay slurries. While both materials are clays and both have equivalent material shear strength using a shear vane, it was found that upon stirring, gas was released immediately and completely from bentonite clay slurry while little if any gas was released from the kaolin slurry. The motivation for the current work is to replicate these tests in a controlled quality test environment and to evaluate the release behavior for another simulant used in DSGREP testing. Three simulant materials were evaluated: 1) a 30 Pa kaolin clay slurry, 2) a 30 Pa bentonite clay slurry, and 3) Rayleigh-Taylor (RT) Simulant (a simulant designed to support DSGREP RT instability testing. Entrained gas was generated in these simulant materials using two methods: 1) application of vacuum over about a 1-minute period to nucleate dissolved gas within the simulant and 2) addition of hydrogen peroxide to generate gas by peroxide decomposition in the simulants over about a 16-hour period. Bubble release was effected by vibrating the test material using an external vibrating table. When testing with hydrogen peroxide, gas release was also accomplished by stirring of the simulant.

  9. An equilibrium model for ligand-modified micellar-enhanced ultrafiltration. Selective separation of metal ions using iminoacetic substituted polyamines and a theoretical model for the titration behavior of polyamines

    SciTech Connect

    Dharmawardana, Udeni Rajaratna

    1992-01-01

    This thesis consists of three chapters. Chapter 1, An equilibrium model for ligand-modified micellar-enhanced ultrafiltration, describes a theoretical model and experimental investigations which used the semi-equilibrium-dialysis method with N-n-dodecyl iminodiacetic acid as the ligand. In Chapter 2, Selective separation of metal ions using iminoacetic substituted polyamines, polyamines with a substituted ligand group are synthesized and used in investigating selective separation of copper ions from aqueous solution. In Chapter 3, A theoretical model for the titration behavior of polyamines, a novel approach to explain the titration behavior of polymeric amines based on the binding behavior of counterions is described. The application of this study is to the investigation of inexpensive and efficient methods of industrial waste water treatment.

  10. Glucose deprivation stimulates Cu(2+) toxicity in cultured cerebellar granule neurons and Cu(2+)-dependent zinc release.

    PubMed

    Isaev, Nickolay K; Genrikhs, Elisaveta E; Aleksandrova, Olga P; Zelenova, Elena A; Stelmashook, Elena V

    2016-05-27

    Copper chloride (0.01mM, 2h) did not have significant influence on the survival of cerebellar granule neurons (CGNs) incubated in balanced salt solution. However, CuCl2 caused severe neuronal damage by glucose deprivation (GD). The glutamate NMDA-receptors blocker MK-801 partially and antioxidant N-acetyl-l-cysteine (NAC) or Zn(2+) chelator, N,N,N',N'-tetrakis(2-pyridylmethyl)ethylenediamine (TPEN) almost entirely protected CGNs from this toxic effect. Measurements of intracellular calcium ions using Fluo-4 AM, or zinc ions with FluoZin-3 AM demonstrated that 1 h-exposure to GD induced intensive increase of Fluo-4 but not FluoZin-3 fluorescence in neurons. The supplementation of solution with CuCl2 caused an increase of FluoZin-3, Fluo-4 and CellROX Green (reactive oxygen species probe) fluorescence by GD. The stimulation of Fluo-4 but not FluoZin-3 fluorescence by copper could be prevented partially by MK-801 and as well as CellROX Green fluorescence by NAC at GD. This data imply that during GD copper ions induce intense displacement zinc ions from intracellular stores, in addition free radical production, glutamate release and Ca(2+) overload of CGNs, that causes death of neurons as a result.

  11. Gas release and conductivity modification studies

    NASA Technical Reports Server (NTRS)

    Linson, L. M.; Baxter, D. C.

    1979-01-01

    The behavior of gas clouds produced by releases from orbital velocity in either a point release or venting mode is described by the modification of snowplow equations valid in an intermediate altitude regime. Quantitative estimates are produced for the time dependence of the radius of the cloud, the average internal energy, the translational velocity, and the distance traveled. The dependence of these quantities on the assumed density profile, the internal energy of the gas, and the ratio of specific heats is examined. The new feature is the inclusion of the effect of the large orbital velocity. The resulting gas cloud models are used to calculate the characteristics of the field line integrated Pedersen conductivity enhancements that would be produced by the release of barium thermite at orbital velocity in either the point release or venting modes as a function of release altitude and chemical payload weight.

  12. [Lateral retinacular release].

    PubMed

    Verdonk, P; Bonte, F; Verdonk, R

    2008-09-01

    This overview of numerous studies discusses, based on short-term and long-term results, which diagnoses are indications for lateral retinacular release. No significant differences in outcome between arthroscopic and open lateral release could be documented. Isolated lateral release offers a good success rate for treating a stable patella with excessive lateral pressure. In patellar instability, the results are less favorable in long-term follow-up evaluation. Hyperlaxity with hypermobility of the patella is an absolute contraindication. Lateral release provides only temporary benefit for patellofemoral osteoarthritis. Proximal and/or distal realignment of the extensor mechanism gives better results than isolated lateral release.

  13. ELECTROMAGNETIC RELEASE MECHANISM

    DOEpatents

    Michelson, C.

    1960-09-13

    An electromagnetic release mechanism is offered that may be used, for example, for supporting a safety rod for a nuclear reactor. The release mechanism is designed to have a large excess holding force and a rapid, uniform, and dependable release. The fast release is accomplished by providing the electromagnet with slotttd polts separated by an insulating potting resin, and by constructing the poles with a ferro-nickel alloy. The combination of these two features materially reduces the eddy current power density whenever the magnetic field changes during a release operation. In addition to these features, the design of the armature is such as to provide ready entrance of fluid into any void that might tend to form during release of the armature. This also improves the release time for the mechanism. The large holding force for the mechanism is accomplished by providing a small, selected, uniform air gap between the inner pole piece and the armature.

  14. Multicomponent Implant Releasing Dexamethasone

    NASA Astrophysics Data System (ADS)

    Nikkola, L.; Vapalahti, K.; Ashammakhi, N.

    2008-02-01

    Several inflammatory conditions are usually treated with corticosteroids. There are various problems like side effects with traditional applications of steroids, e.g. topical, or systemic routes. Local drug delivery systems have been studied and developed to gain more efficient administration with fewer side effects. Earlier, we reported on developing Dexamethasone (DX) releasing biodegradable fibers. However, their drug release properties were not satisfactory in terms of onset of drug release. Thus, we assessed the development of multicomponent (MC) implant to enhance earlier drug release from such biodegradable fibers. Poly (lactide-co-glycolide) (PLGA) and 2 wt-% and 8 wt-% DX were compounded and extruded with twin-screw extruder to form of fibers. Some of the fibers were sterilized to obtain a change in drug release properties. Four different fiber classes were studied: 2 wt-%, 8 wt-%, sterilized 2 wt-%, and sterilized 8 wt-%. 3×4 different DX-releasing fibers were then heat-pressed to form one multicomponent rod. Half of the rods where sterilized. Drug release was measured from initial fibers and multicomponent rods using a UV/VIS spectrometer. Shear strength and changes in viscosity were also measured. Drug release studies showed that drug release commenced earlier from multicomponent rods than from component fibers. Drug release from multicomponent rods lasted from day 30 to day 70. The release period of sterilized rods extended from day 23 to day 57. When compared to the original component fibers, the drug release from MC rods commenced earlier. The initial shear strength of MC rods was 135 MPa and decreased to 105 MPa during four weeks of immersion in phosphate buffer solution. Accordingly, heat pressing has a positive effect on drug release. After four weeks in hydrolysis, no disintegration was observed.

  15. Comprehensive thermochemistry for the hydration of copper ions

    NASA Astrophysics Data System (ADS)

    Armentrout, Peter

    2015-03-01

    Cross sections for the threshold collision-induced dissociation (TCID) of Cu2+(H2O)n, where n = 8 - 10, and of CuOH+(H2O)n, where n = 1 - 4, are measured using a guided ion beam tandem mass spectrometer. In both cases, the primary dissociation pathway is found to be loss of a single water molecule followed by the sequential loss of additional water molecules. In the Cu2+ complexes, charge separation to form CuOH+(H2O)3andH+(H2O)3 is also observed and CuOH+(H2O) competitively loses both H2O and OH. The data are analyzed using a statistical model after accounting for internal and kinetic energy distributions, multiple collisions, and kinetic shifts to obtain 0 K bond dissociation energies (BDEs). In addition, BDEs for the loss of OH from CuOH+(H2O)n where n = 0 - 4 are derived using the experimental BDEs for dissociation of CuOH+(H2O)n and literature values for Cu+(H2O)n. Experimental BDEs are compared to theoretical BDEs determined at several levels of theory with reasonable agreement. Structural information regarding complexes of CuOH+(H2O)n, where n = 2 - 9, are also obtained using infrared photodissociation spectroscopy (IRPD) in the OH stretching region and comparison to theoretical spectra. The IRPD spectra of all complexes where n >= 3 are consistent with structures generally having a coordination number (CN) of 4 although CuOH+(H2O)7 exhibits bands characteristic of both CN = 4 and CN = 5 isomers.

  16. Adsorption of copper ion on magnetite-immobilised chitin.

    PubMed

    Wong, K S; Wong, K H; Ng, S; Chung, W K; Wong, P K

    2007-01-01

    The adsorption of Cu2+ from aqueous solution by magnetite-immobilised chitin (MC) was studied in batch mode. Two conventional adsorbents, cation exchange resin (CER) and activated carbon (AC) were used for the comparison. The physicochemical parameters including pH, concentration of adsorbent, temperature and initial Cu2+ concentration were optimised. Under the optimised conditions, the removal efficiencies of Cu2+ for MC, CER and AC were 91.67, 93.36 and 89.16%, respectively. In addition, the removal capacities of Cu2+ for MC, CER and AC were 56.71, 74.84 and 6.55 mg/g, respectively. The adsorption isotherm studies indicated that the adsorptive behaviour of Cu2+ on three adsorbents could be well described by the Langmuir model. The maximum adsorption capacities (qmax) for MC, CER and AC were 53.19, 89.29 and 5.82 mg/g, respectively. The applicability of the kinetic model has been investigated for MC. Experimental results indicated that a pseudo-second-order reaction model provided the best description of the data with a correlation coefficient 0.999 for different initial Cu2+ concentrations. The rate constants were also determined. Various thermodynamic parameters such as standard free energy (DeltaG 0), enthalpy (DeltaH 0) and entropy (DeltaS 0) were calculated for predicting the adsorption nature of MC. The results indicated that this system was a spontaneous and endothermic process.

  17. Morphology of gold and copper ion-plated coatings

    NASA Technical Reports Server (NTRS)

    Spalvins, T.

    1978-01-01

    Copper and gold films (0.2 to 2 microns thick) were ion plated onto polished 304-stainless-steel, glass, mica surfaces. These coatings were examined by SEM for defects in their morphological growth. Three types of defects were distinguished: nodular growth, abnormal or runaway growth, and spits. The cause for each type of defect was investigated. Nodular growth is due to inherent substrate microdefects, abnormal or runaway growth is due to external surface inclusions, and spits are due to nonuniform evaporation (ejection of droplets). All these defects induce stresses and produce porosity in the coatings and thus weaken their mechanical properties. During surface rubbing, large nodules are pulled out, leaving vacancies in the coatings.

  18. Mechanisms of Copper Ion Mediated Huntington's Disease Progression

    PubMed Central

    Fox, Jonathan H.; Kama, Jibrin A.; Lieberman, Gregory; Chopra, Raman; Dorsey, Kate; Chopra, Vanita; Volitakis, Irene; Cherny, Robert A.; Bush, Ashley I.; Hersch, Steven

    2007-01-01

    Huntington's disease (HD) is caused by a dominant polyglutamine expansion within the N-terminus of huntingtin protein and results in oxidative stress, energetic insufficiency and striatal degeneration. Copper and iron are increased in the striata of HD patients, but the role of these metals in HD pathogenesis is unknown. We found, using inductively-coupled-plasma mass spectroscopy, that elevations of copper and iron found in human HD brain are reiterated in the brains of affected HD transgenic mice. Increased brain copper correlated with decreased levels of the copper export protein, amyloid precursor protein. We hypothesized that increased amounts of copper bound to low affinity sites could contribute to pro-oxidant activities and neurodegeneration. We focused on two proteins: huntingtin, because of its centrality to HD, and lactate dehydrogenase (LDH), because of its documented sensitivity to copper, necessity for normoxic brain energy metabolism and evidence for altered lactate metabolism in HD brain. The first 171 amino acids of wild-type huntingtin, and its glutamine expanded mutant form, interacted with copper, but not iron. N171 reduced Cu2+ in vitro in a 1∶1 copper∶protein stoichiometry indicating that this fragment is very redox active. Further, copper promoted and metal chelation inhibited aggregation of cell-free huntingtin. We found decreased LDH activity, but not protein, and increased lactate levels in HD transgenic mouse brain. The LDH inhibitor oxamate resulted in neurodegeneration when delivered intra-striatially to healthy mice, indicating that LDH inhibition is relevant to neurodegeneration in HD. Our findings support a role of pro-oxidant copper-protein interactions in HD progression and offer a novel target for pharmacotherapeutics. PMID:17396163

  19. Dendritic Release of Neurotransmitters.

    PubMed

    Ludwig, Mike; Apps, David; Menzies, John; Patel, Jyoti C; Rice, Margaret E

    2016-12-06

    Release of neuroactive substances by exocytosis from dendrites is surprisingly widespread and is not confined to a particular class of transmitters: it occurs in multiple brain regions, and includes a range of neuropeptides, classical neurotransmitters, and signaling molecules, such as nitric oxide, carbon monoxide, ATP, and arachidonic acid. This review is focused on hypothalamic neuroendocrine cells that release vasopressin and oxytocin and midbrain neurons that release dopamine. For these two model systems, the stimuli, mechanisms, and physiological functions of dendritic release have been explored in greater detail than is yet available for other neurons and neuroactive substances. © 2017 American Physiological Society. Compr Physiol 7:235-252, 2017.

  20. Release the Body, Release the Mind.

    ERIC Educational Resources Information Center

    Stoner, Martha Goff

    1998-01-01

    A college English teacher describes the anxiety and resentment of students during in-class writing assignments and the successful classroom use of meditation and body movement. Movement seemed to relax the students, change their attitudes, and release their creative impulses to write. Implications related to the body-mind connection are pondered.…

  1. [Preparation of hydrophilic matrix sustained release tablets of total lactones from Andrographis paniculata and study on its in vitro release mechanism].

    PubMed

    Xu, Fang-Fang; Shi, Wei; Zhang, Hui; Guo, Qing-Ming; Wang Zhen-Zhong; Bi, Yu-An; Wang, Zhi-Min; Xiao, Wei

    2015-01-01

    In this study, hydrophilic matrix sustained release tablets of total lactones from Andrographis paniculata were prepared and the in vitro release behavior were also evaluated. The optimal prescription was achieved by studying the main factor of the type and amount of hydroxypropyl methylcellulose (HPMC) using single factor test and evaluating through cumulative release of three lactones. No burst drug release from the obtained matrix tablets was observed. Drug release sustained to 14 h. The release mechanism of three lactones from A. paniculata was accessed by zero-order, first-order, Higuchi and Peppas equation. The release behavior of total lactones from A. paniculata was better agreed with Higuchi model and the drug release from the tablets was controlled by degradation of the matrix. The preparation of hydrophilic matrix sustained release tablets of total lactones from A. paniculata with good performance of drug release was simple.

  2. An understanding of modified release matrix tablets behavior during drug dissolution as the key for prediction of pharmaceutical product performance - case study of multimodal characterization of quetiapine fumarate tablets.

    PubMed

    Kulinowski, Piotr; Woyna-Orlewicz, Krzysztof; Rappen, Gerd-Martin; Haznar-Garbacz, Dorota; Węglarz, Władysław P; Dorożyński, Przemysław P

    2015-04-30

    Motivation for the study was the lack of dedicated and effective research and development (R&D) in vitro methods for oral, generic, modified release formulations. The purpose of the research was to assess multimodal in vitro methodology for further bioequivalence study risk minimization. Principal results of the study are as follows: (i) Pharmaceutically equivalent quetiapine fumarate extended release dosage form of Seroquel XR was developed using a quality by design/design of experiment (QbD/DoE) paradigm. (ii) The developed formulation was then compared with originator using X-ray microtomography, magnetic resonance imaging and texture analysis. Despite similarity in terms of compendial dissolution test, developed and original dosage forms differed in micro/meso structure and consequently in mechanical properties. (iii) These differences were found to be the key factors of failure of biorelevant dissolution test using the stress dissolution apparatus. Major conclusions are as follows: (i) Imaging methods allow to assess internal features of the hydrating extended release matrix and together with the stress dissolution test allow to rationalize the design of generic formulations at the in vitro level. (ii) Technological impact on formulation properties e.g., on pore formation in hydrating matrices cannot be overlooked when designing modified release dosage forms.

  3. A computational study of the effect of the metal organic framework environment on the release of chemically stored nitric oxide.

    PubMed

    Li, Tanping; Taylor-Edinbyrd, Kiara; Kumar, Revati

    2015-09-28

    The use of copper based metal organic frameworks as a vehicle for the storage and delivery of chemically stored nitric oxide has been proposed based on recent experiments [J. Am. Chem. Soc., 2012, 134, 3330-3333]. In these experiments copper based metal organic frameworks (MOFs) suspended in ethanol catalytically convert chemically stored nitric oxide (in the S-nitrosothiol or RSNO form) to free nitric oxide at a slow and sustained rate, as compared to a quick release in a solution of ethanol containing free copper ions. In order to gain insight on the effect of the MOF environment on the catalytic activity, a combination of electronic structure calculations on representative clusters and classical simulations using a force-field (partly parameterized on the above calculations) is used to study a simple RSNO species, S-nitrosomethane (CH3SNO) as well as the biologically compatible S-nitrosocysteine, both in the MOF and free copper solution. The free energy profiles of bringing the RSNO species to the catalytic centers have been compared and related to the different solvation environments of the copper catalyst in the complex solvated MOF and in free copper solution. Surprisingly, in the case of the simple CH3SNO moiety as well as the S-nitrosocysteine case, the free energy profile of bringing the first RSNO from the center of one of the pores to the catalytic site in the pore is very similar to the free solution case. On the other hand, bringing a second RSNO molecule to the same catalytic site or to the adjacent catalytic copper site show relatively higher barriers. These studies help shed light on the sustained nitric oxide release in the MOF environment.

  4. Performance of Male Psychopaths Following Conditional Release from Prison.

    ERIC Educational Resources Information Center

    Hart, Stephen D.; And Others

    1988-01-01

    Administered Psychopathy Checklist (PCL) to criminals being released from prison on parole or mandatory supervision, then examined official parole supervision files for postrelease behavior. Violation of release conditions, suspensions, and presentation of supervisory problems were directly proportional, and the probability of subjects remaining…

  5. Post-release behavior and movement patterns of Chinook salmon (Oncorhynchus tshawytscha) and coho salmon (Oncorhynchus kisutch) after capture using alternative commercial fish gear, lower Columbia River, Washington and Oregon, 2013

    USGS Publications Warehouse

    Liedtke, Theresa L.; Kock, Tobias J.; Evans, Scott D.; Hansen, Gabriel S.; Rondorf, Dennis W.

    2014-01-01

    In 2011 and 2012, WDFW conducted post-release mortality studies of steelhead (Oncorhynchus mykiss), Chinook salmon (Oncorhynchus tshawytscha), and coho salmon (Oncorhynchus kisutch) that were captured using beach or purse seines. These studies were comprised of two groups of fish tagged with passive integrated transponder tags (PIT tags): (1) treatment fish that were captured by one of the gear types 9–25 river kilometers (rkm) downstream of Bonneville Dam (rkm 234); and (2) control fish that were captured at the Adult Fish Facility near the Washington shore fish ladder at Bonneville Dam, and then transported and released 8 rkm downstream of the Bonneville Dam. Fish were confirmed to have survived if they moved upstream and were detected on PIT-tag antennas at or upstream of Bonneville Dam, were recovered at hatcheries or at the dam, or were captured by commercial or sport fishers. Post-release survival estimates were higher for steelhead (89–98 percent) than for Chinook salmon and coho salmon (50–90 percent; Washington Department of Fish and Wildlife, unpub. data, 2014). However, some Chinook salmon and coho salmon return to hatcheries, or spawn in the mainstem Columbia River and in tributaries downstream of Bonneville Dam. The proportion of Chinook salmon and coho salmon in the treatment group that were destined for areas downstream of Bonneville Dam likely was higher than in the control group because the control fish were collected as they were attempting to pass the dam. If this assertion was true, mortality would have been overestimated in these studies, so WDFW developed a study plan to determine the post-release movements and intended location of Chinook salmon and coho salmon collected with beach and purse seines in the lower Columbia River.

  6. Effect of passivation on the dissolution behavior of Ti6A14V and vacuum-brazed Ti6A14V in Hank's ethylene diamine tetra-acetic acid solution Part I Ion release.

    PubMed

    Lee, T M; Chang, E; Yang, C Y

    1999-09-01

    This work aims to investigate the effects of three factors, namely: (1) two differently prepared materials (as-polished Ti6A14V and 2 h brazed Ti6A14V); (2) three different surface passivation treatments (34% nitric acid passivation, 400 degrees C heated in air, and aged in 100 degrees C de-ionized water); and (3) periods of immersion time (up to 32 days), on trace element release in Hank's ethylene diamine tetra-acetic acid (EDTA) solution. After passivation and autoclaving treatment, the specimens were immersed in 8.0 mM EDTA in Hank's solution and maintained at 37 degrees C for periods of time up to 32 days. The 400 degrees C -treated specimens exhibit a substantial reduction in constituent release, which may be attributed to the higher thickness and rutile structure of the surface oxides. For acid-passivated and water-aged treatments, a highly significant decrease in the trace levels of Ti, A1, and V is detected from the brazed Ti6A14V compared to those obtained from the Ti6A14V specimens. It is hypothesized that an anatase-rutile transformation of surface TiO_2 is likely to occur, accelerated by the elements of copper and nickel in the brazed specimens. In addition, a significant time-related decrease in constituent release rate is observed for all kinds of specimens throughout the 0-8 day experimental period. The implication of the results is discussed.

  7. Rad-Release

    SciTech Connect

    2011-01-01

    The R&D 100 Award winning Rad-Release Chemical Decontamination Technology is a highly effective (up to 99% removal rate), affordable, patented chemical-foam-clay decontamination process tailored to specific radiological and metal contaminants, which is applicable to a wide variety of substrates. For more information about this project, visit http://www.inl.gov/rd100/2011/rad-release/

  8. Rad-Release

    ScienceCinema

    None

    2016-07-12

    The R&D 100 Award winning Rad-Release Chemical Decontamination Technology is a highly effective (up to 99% removal rate), affordable, patented chemical-foam-clay decontamination process tailored to specific radiological and metal contaminants, which is applicable to a wide variety of substrates. For more information about this project, visit http://www.inl.gov/rd100/2011/rad-release/

  9. Controlled-release microchips.

    PubMed

    Sharma, Sadhana; Nijdam, A Jasper; Sinha, Piyush M; Walczak, Robbie J; Liu, Xuewu; Cheng, Mark M-C; Ferrari, Mauro

    2006-05-01

    Efficient drug delivery remains an important challenge in medicine: continuous release of therapeutic agents over extended time periods in accordance with a predetermined temporal profile; local delivery at a constant rate to the tumour microenvironment to overcome much of the systemic toxicity and to improve antitumour efficacy; improved ease of administration, and increasing patient compliance required are some of the unmet needs of the present drug delivery technology. Microfabrication technology has enabled the development of novel controlled-release microchips with capabilities not present in the current treatment modalities. In this review, the current status and future prospects of different types of controlled-release microchips are summarised and analysed with reference to microneedle-based microchips, as well as providing an in-depth focus on microreservoir-based and nanoporous microchips.

  10. RAVEN Beta Release

    SciTech Connect

    Rabiti, Cristian; Alfonsi, Andrea; Cogliati, Joshua Joseph; Mandelli, Diego; Kinoshita, Robert Arthur; Wang, Congjian; Maljovec, Daniel Patrick; Talbot, Paul William

    2016-02-01

    This documents the release of the Risk Analysis Virtual Environment (RAVEN) code. A description of the RAVEN code is provided, and discussion of the release process for the M2LW-16IN0704045 milestone. The RAVEN code is a generic software framework to perform parametric and probabilistic analysis based on the response of complex system codes. RAVEN is capable of investigating the system response as well as the input space using Monte Carlo, Grid, or Latin Hyper Cube sampling schemes, but its strength is focused toward system feature discovery, such as limit surfaces, separating regions of the input space leading to system failure, using dynamic supervised learning techniques. RAVEN has now increased in maturity enough for the Beta 1.0 release.

  11. Altitude release mechanism

    DOEpatents

    Kulhanek, Frank C.

    1977-01-01

    An altitude release mechanism for releasing a radiosonde or other measuring instrument from a balloon carrying it up into the atmosphere includes a bottle partially filled with water, a tube sealed into the bottle having one end submerged in the water in the bottle and the free end extending above the top of the bottle and a strip of water-disintegrable paper held within the free end of the tube linking the balloon to the remainder of the package. As the balloon ascends, the lowered atmospheric air pressure causes the air in the bottle to expand, forcing the water in the bottle up the tubing to wet and disintegrate the paper, releasing the package from the balloon.

  12. Characterization of Release Mechanism in Polymeric Drug Delivery Systems

    NASA Astrophysics Data System (ADS)

    Laplante, Arthur James; Plachy, Robin Marie; Aou, Kaoru; Ferguson, Jake; Hsu, Shaw Ling

    2006-03-01

    Our polymeric drug delivery system is based on our understanding of phase behavior of polymers [e.g poly(lactic acid)], low molecular drugs and various solvents used in processing. Clearly the different morphologies achieved, based on different phase separation kinetics, can affect drug release rates. Release of drugs, in most cases, involves the exchange between the extraction media and drug. We have characterized the transport behavior using a number of unique techniques. Reflectance infrared spectroscopy has given us a detailed description of the release rate of drugs into the extraction media. Surface plasmon resonance has shown the overall mass loss. UV-visible spectroscopy has yielded the concentration of drug in the solution. These measurements are compared to the release mechanism based on Fickian diffusion. The two step release rates observed can only be explained by taking into account differences in the morphological features of the phase separated films.

  13. Uncoupling primer and releaser responses to pheromone in honey bees

    NASA Astrophysics Data System (ADS)

    Grozinger, Christina M.; Fischer, Patrick; Hampton, Jacob E.

    2007-05-01

    Pheromones produce dramatic behavioral and physiological responses in a wide variety of species. Releaser pheromones elicit rapid responses within seconds or minutes, while primer pheromones produce long-term changes which may take days to manifest. Honeybee queen mandibular pheromone (QMP) elicits multiple distinct behavioral and physiological responses in worker bees, as both a releaser and primer, and thus produces responses on vastly different time scales. In this study, we demonstrate that releaser and primer responses to QMP can be uncoupled. First, treatment with the juvenile hormone analog methoprene leaves a releaser response (attraction to QMP) intact, but modulates QMP’s primer effects on sucrose responsiveness. Secondly, two components of QMP (9-ODA and 9-HDA) do not elicit a releaser response (attraction) but are as effective as QMP at modulating a primer response, downregulation of foraging-related brain gene expression. These results suggest that different responses to a single pheromone may be produced via distinct pathways.

  14. Sustain-release of various drugs from leucaena leucocephala polysaccharide.

    PubMed

    Jeevanandham, S; Sekar, M; Dhachinamoorthi, D; Muthukumaran, M; Sriram, N; Joysaruby, J

    2010-01-01

    This study examines the sustained release behavior of both water-soluble (acetaminophen, caffeine, theophylline and salicylic acid) and water-insoluble (indomethacin) drugs from Leucaena leucocephala seed Gum isolated from Leucaena leucocephala kernel powder. It further investigates the effect of incorporation of diluents like microcrystalline cellulose and lactose on release of caffeine and partial cross-linking of the gum (polysaccharide) on release of acetaminophen. Applying exponential equation, the mechanism of release of soluble drugs was found to be anomalous. The insoluble drug showed near case II or zero-order release mechanism. The rate of release was in the decreasing order of caffeine, acetaminophen, theophylline, salicylic acid and indomethacin. An increase in release kinetics of drug was observed on blending with diluents. However, the rate of release varied with type and amount of blend in the matrix. The mechanism of release due to effect of diluents was found to be anomalous. The rate of release of drug decreased on partial cross-linking and the mechanism of release was found to be super case II.

  15. Releasable Asbestos Field Sampler

    EPA Science Inventory

    Asbestos aerosolization (or releasability) is the potential for fibrous asbestos structures that are present in a material or on a solid surface to become airborne when the source is disturbed by human activities or natural forces. In turn, the magnitude of the airborne concentra...

  16. Release of OLe peanut

    Technology Transfer Automated Retrieval System (TEKTRAN)

    OLe is a high oleic Spanish-type peanut that has excellent yield and enhanced Sclerotinia blight and pod rot resistance when compared to other high oleic Spanish cultivars. The purpose for releasing OLe is to provide peanut producers with a true Spanish peanut that is high oleic and has enhanced yi...

  17. Hydraulic release oil tool

    SciTech Connect

    Mims, M.G.; Mueller, M.D.; Ehlinger, J.C.

    1992-03-11

    This patent describes a hydraulic release tool. It comprises a setting assembly; a coupling member for coupling to drill string or petroleum production components, the coupling member being a plurality of sockets for receiving the dogs in the extended position and attaching the coupling member the setting assembly; whereby the setting assembly couples to the coupling member by engagement of the dogs in the sockets of releases from and disengages the coupling member in movement of the piston from its setting to its reposition in response to a pressure in the body in exceeding the predetermined pressure; and a relief port from outside the body into its bore and means to prevent communication between the relief port and the bore of the body axially of the piston when the piston is in the setting position and to establish such communication upon movement of the piston from the setting position to the release position and reduce the pressure in the body bore axially of the piston, whereby the reduction of the pressure signals that the tool has released the coupling member.

  18. Data Release Summary Statement

    Atmospheric Science Data Center

    2016-11-14

    ... 3 CALIOP Level 1 data are released with a product maturity classification of Validated Stage1 , indicating that initial validation of ... users for evaluation and to provide feedback to the CALIOP algorithm development team. Users should carefully read the section of the Data ...

  19. Influence of formulation composition and process on the characteristics and in vitro release from PLGA-based sustained release injectables.

    PubMed

    Meeus, Joke; Scurr, David J; Appeltans, Bernard; Amssoms, Katie; Annaert, Pieter; Davies, Martyn C; Roberts, Clive J; Van den Mooter, Guy

    2015-02-01

    Understanding and controlling the in vitro release behavior of a formulation is a first step toward rationalized selection of a solubility enhancing formulation strategy with a desired release profile in vivo. Therefore six model formulations, representing three different formulation strategies, were physicochemically analyzed and their in vitro release was determined. Solid dispersions based on a PLGA/PVP matrix were compared to solid dispersions in a pure PLGA matrix. Additionally these solid dispersion strategies were compared to the strategy of particle size reduction by means of an API microsuspension. Depending on composition and manufacturing method, formulations varied in particle size, porosity, phase behavior, surface coverage and physical state of the API. This resulted in observed differences in their in vitro release profile. For the various formulation strategies tested both a porous PLGA-based formulation and PLGA/PVP-based formulations, resulted in vitro in sustained release of the poorly soluble API with over 50% of drug released after 24h. For PLGA-based formulations the porosity was identified as a critical parameter influencing in vitro drug release. For the PLGA/PVP-based formulations the release rate can be tailored by the amount of PLGA present. Particle size reduction resulted in immediate total drug release.

  20. Uniform biodegradable microparticle systems for controlled release

    PubMed Central

    Xia, Yujie; Pack, Daniel W.

    2014-01-01

    Drug delivery methods can impact efficacy as much as the nature of the drug itself. Microparticles made of biodegradable polymers such as poly(D,L-lactide-co-glycolide) and poly(lactic acid) (PLA) have been studied extensively for controlled release of diverse drugs. By using a modified solvent extraction/evaporation method called precision particle fabrication (PPF), uniform microparticles such as single-wall microspheres, double-wall microspheres and liquid-core microcapsules have been fabricated with precise control of their geometric structures. By producing particles of uniform size, which has crucial impact on drug release behaviors, PPF-fabricated microparticles provide unique insights about drug release mechanism. Using small-molecule and macromolecule model drugs, our group demonstrated that physicochemical properties of the polymers and drugs and structural properties of the matrix can greatly impact drug distribution within microparticles, particle erosion and drug release rates. By careful selection of particle size and shell thickness, uniform microparticles can achieve “zero-order”, pulsatile or tandem release of drugs. PMID:12106984

  1. Nonequivalent release sites govern synaptic depression

    PubMed Central

    Wen, Hua; McGinley, Matthew J.; Mandel, Gail; Brehm, Paul

    2016-01-01

    Synaptic depression is prominent among synapses, but the underlying mechanisms remain uncertain. Here, we use paired patch clamp recording to study neuromuscular transmission between the caudal primary motor neuron and target skeletal muscle in zebrafish. This synapse has an unusually low number of release sites, all with high probabilities of release in response to low-frequency stimulation. During high-frequency stimulation, the synapse undergoes short-term depression and reaches steady-state levels of transmission that sustain the swimming behavior. To determine the release parameters underlying this steady state, we applied variance analysis. Our analysis revealed two functionally distinct subclasses of release sites differing by over 60-fold in rates of vesicle reloading. A slow reloading class requires seconds to recover and contributes to depression onset but not the steady-state transmission. By contrast, a fast reloading class recovers within tens of milliseconds and is solely responsible for steady-state transmission. Thus, in contrast to most current models that assign levels of steady-state depression to vesicle availability, our findings instead assign this function to nonuniform release site kinetics. The duality of active-site properties accounts for the highly nonlinear dependence of steady-state depression levels on frequency. PMID:26715759

  2. Release Fraction Evaluation

    SciTech Connect

    Bamberger, Judith A.; Glissmeyer, John A.

    2004-01-01

    This document presents results of experiments conducted to measure release fractions during certain tank retrieval processes. The tests were performed in a 1/4 scale model of a waste storage tank. The retrieval processes simulated were: (1) Discharging liquid or slurry from the mouth of a vertically oriented two-in. Schedule 40 pipe. The discharging material was in free-fall from the mouth of the pipe near the top of the tank into a liquid or slurry pool at the bottom of the tank. (2) The jet from a 9/16-in.-diameter nozzle transferring liquid or slurry waste from one side of the tank to the other. The discharging liquid was aimed at the opposite side of the tank from the nozzle and either impacted the tank wall or fell into a liquid or slurry pool in the bottom of the tank. (3) A high pressure fan jet of liquid striking a steel plate or simulated waste from a stand-off distance of a few inches. For each process, a water-soluble fluorescent dye was added to the liquid fraction as a tracer. Kaolin clay was used to represent the solids. The tank was covered and there was no forced ventilation in the tank during the tests. Six air samples were collected during each test. The air samples were collected at fixed positions in the tank. The air sample filters were dried and weighed to determine the solids collection. The fluorescent dye was then leached from each filter and quantified with a fluorometer to determine the collection of liquid. Samples of the slurry and liquid simulants were also collected to determine the quantities of simulant used in each test. To calculate the release fraction, the quantity collected on each air sample was adjusted for the fraction of the tank volume sampled and divided by the quantity of material exposed in the simulation. The method was not as sensitive for the solids content as it was for the liquid content, but in those instances where a solids release fraction was determined, it was in relatively good agreement with that of the

  3. Thyrotropin Releasing Hormone (TRH) in goldfish (Carassius auratus): role in the regulation of feeding and locomotor behaviors and interactions with the orexin system and cocaine- and amphetamine regulated transcript (CART).

    PubMed

    Abbott, Meagan; Volkoff, Hélène

    2011-02-01

    TRH is a peptide produced by the hypothalamus which major function in mammals is the regulation of TSH secretion by the pituitary. In fish, TRH does not appear to affect TSH secretion, suggesting that it might regulate other functions. In this study, we assessed the effects of central (intracerebroventricular, icv) injections of TRH on feeding and locomotor behavior in goldfish. TRH at 10 and 100 ng/g, but not 1 ng/g, significantly increased feeding and locomotor behaviors, as indicated by an increase in food intake and in the number of total feeding acts as compared to saline-injected fish. In order to assess possible interactions between TRH and other appetite regulators, we examined the effects of icv injections of TRH on the hypothalamic expression of orexin, orexin receptor and CART. The mRNA expression levels of all three peptides were significantly increased in fish injected with TRH at 100 ng/g as compared to saline-injected fish. Fasting increased TRH, orexin, and orexin receptor hypothalamic mRNA levels and decreased CART hypothalamic mRNA levels. Our results suggest that TRH is involved in the regulation of feeding/locomotor activity in goldfish and that this action is associated with a stimulation of both the orexin and CART systems.

  4. Releasable locking mechanisms

    NASA Technical Reports Server (NTRS)

    Ahmed, Rafiq (Inventor); Wingate, Robert J. (Inventor)

    2005-01-01

    In the aerospace field spacecraft components are held together by separation systems until a specific time when they must be separated or deployed. Customarily a threaded joining bolt engages one of the components to be joined, and a threaded nut is placed on that bolt against the other component so they can be drawn together by a releasable locking assembly. The releasable locking assembly herein includes a plunger having one end coupled to one end of a plunger bolt. The other end is flanged to abut and compress a coil spring when the plunger is advanced toward the interface plane between the two components. When the plunger is so advanced toward the interface plane, the end of the plunger bolt can be connected to the joining bolt. Thus during retraction the joining bolt is drawn to one side of the interface plane by the force of the expanding spring.

  5. Cryogenic hydrogen release research.

    SciTech Connect

    LaFleur, Angela Christine

    2015-12-01

    The objective of this project was to devolop a plan for modifying the Turbulent Combustion Laboratory (TCL) with the necessary infrastructure to produce a cold (near liquid temperature) hydrogen jet. The necessary infrastructure has been specified and laboratory modifications are currently underway. Once complete, experiments from this platform will be used to develop and validate models that inform codes and standards which specify protection criteria for unintended releases from liquid hydrogen storage, transport, and delivery infrastructure.

  6. Sudden releases of gases

    NASA Astrophysics Data System (ADS)

    Chaloupecká, Hana; Jaňour, Zbyněk; Jurčáková, Klára; Kukačka, Libor; Nosek, Štěpán

    2014-03-01

    Conurbations all over the world have enlarged for numberless years. The accidental or intentional releases of gases become more frequent. Therefore, these crises situations have to be studied. The aim of this paper is to describe experiments examining these processes that were carried out in the laboratory of Environmental Aerodynamics of the Institute of Thermomechanics AS CR in Nový Knín. Results show huge puff variability from replica to replica.

  7. Slow-release fertilizer

    NASA Technical Reports Server (NTRS)

    Ming, Douglas W. (Inventor); Golden, D. C. (Inventor)

    1992-01-01

    A synthetic apatite containing agronutrients and a method for making the apatite are disclosed. The apatite comprises crystalline calcium phosphate having agronutrients dispersed in the crystalline structure. The agronutrients can comprise potassium, magnesium, sulfur, iron, manganese, molybdenum, chlorine, boron, copper and zinc in amounts suited for plant growth. The apatite can optionally comprise a carbonate and/or silicon solubility control agent. The agronutrients are released slowly as the apatite dissolves.

  8. Slow-release fertilizer

    NASA Technical Reports Server (NTRS)

    Ming, Douglas W. (Inventor); Golden, Dadigamuwage C. (Inventor)

    1995-01-01

    A synthetic apatite containing agronutrients and a method for making the apatite are disclosed. The apatite comprises crystalline calcium phosphate having agronutrients dispersed in the crystalline structure. The agronutrients can comprise potassium, magnesium, sulfur, iron, manganese, molybdenum, chlorine, boron, copper and zinc in amounts suited for plant growth. The apatite can optionally comprise a carbonate and/or silicon solubility control agent. The agronutrients are released slowly as the apatite dissolves.

  9. EIA new releases

    SciTech Connect

    Not Available

    1994-12-01

    This report was prepared by the Energy Information Administration. It contains news releases on items of interest to the petroleum, coal, nuclear, electric and alternate fuels industries ranging from economic outlooks to environmental concerns. There is also a listing of reports by industry and an energy education resource listing containing sources for free or low-cost energy-related educational materials for educators and primary and secondary students.

  10. Slow-release fertilizer

    NASA Astrophysics Data System (ADS)

    Ming, Douglas W.; Golden, D. C.

    1992-10-01

    A synthetic apatite containing agronutrients and a method for making the apatite are disclosed. The apatite comprises crystalline calcium phosphate having agronutrients dispersed in the crystalline structure. The agronutrients can comprise potassium, magnesium, sulfur, iron, manganese, molybdenum, chlorine, boron, copper and zinc in amounts suited for plant growth. The apatite can optionally comprise a carbonate and/or silicon solubility control agent. The agronutrients are released slowly as the apatite dissolves.

  11. Clinton releases oceans report

    NASA Astrophysics Data System (ADS)

    Showstack, Randy

    U.S. President Bill Clinton is trying to beat the clock on the January 20 close of his administration by maintaining a flurry of activity on resource and conservation issues.During a December 4 speech in Washington, D.C., he released a broad-ranging report by the Presidents Panel on Ocean Exploration, entitled “Discovering Earth's Final Frontier: A U.S. Strategy for Ocean Exploration.”

  12. Laboratory Crowd Behavior

    DTIC Science & Technology

    2010-06-25

    Approved for Public Release 13-Feb-15 4 Conceptual Framework • Based on the work of Kurt Lewin • Field Theory in Social Science (1948) • Principles...Army’s Target Behavioral Response Laboratory. 15. SUBJECT TERMS crowd, Lewin , field theory, non-lethal weapons, crowd metrics, crowd modeling and

  13. Evaluation of a soil incubation method to characterize nitrogen release patterns of slow- and controlled-release fertilizers.

    PubMed

    Medina, L Carolina; Sartain, Jerry B; Obreza, Thomas A; Hall, William L; Thiex, Nancy J

    2014-01-01

    Several technologies have been proposed to characterize the nutrient release patterns of slow-release fertilizers (SRF) and controlled-release fertilizers (CRF) during the last few decades. These technologies have been developed mainly by manufacturers, and are product-specific, based on the regulation and analysis of each SRF and CRF product. Despite previous efforts to characterize SRF and CRF materials, no standardized, validated method exists to assess their nutrient release patterns. However, the increased production and distribution of these materials in specialty and nonspecialty markets requires an appropriate method to verify product claims and material performance. A soil incubation column leaching procedure was evaluated to determine its suitability as a standard method to estimate nitrogen (N) release patterns of SRFs and CRFs during 180 days. The influence of three soil/sand ratios, three incubation temperatures, and four soils on method behavior was assessed using five SRFs and three CRFs. In general, the highest soil/sand ratio increased the N release rate of all materials, but this effect was more marked for the SRFs. Temperature had the greatest influence on N release rates. For CRFs, the initial N release rates and the percentage N released/day increased as temperature increased. For SRFs, raising the temperature from 25 to 35 degreesC increased initial N release rate and the total cumulative N released, and almost doubled the percentage released/day. The percentage N released/day from all products generally increased as the texture of the soil changed from sandy to loamy (lowa>California>Pennsylvania>Florida). The soil incubation technique was demonstrated to be robust and reliable for characterizing N release patterns from SRFs and CRFs. The method was reproducible, and variations in soil/sand ratio, temperature, and soil had little effect on the results.

  14. Triggered Release from Polymer Capsules

    SciTech Connect

    Esser-Kahn, Aaron P.; Odom, Susan A.; Sottos, Nancy R.; White, Scott R.; Moore, Jeffrey S.

    2011-07-06

    Stimuli-responsive capsules are of interest in drug delivery, fragrance release, food preservation, and self-healing materials. Many methods are used to trigger the release of encapsulated contents. Here we highlight mechanisms for the controlled release of encapsulated cargo that utilize chemical reactions occurring in solid polymeric shell walls. Triggering mechanisms responsible for covalent bond cleavage that result in the release of capsule contents include chemical, biological, light, thermal, magnetic, and electrical stimuli. We present methods for encapsulation and release, triggering methods, and mechanisms and conclude with our opinions on interesting obstacles for chemically induced activation with relevance for controlled release.

  15. Thermal post-treatment alters nutrient release from a controlled-release fertilizer coated with a waterborne polymer

    PubMed Central

    Zhou, Zijun; Du, Changwen; Li, Ting; Shen, Yazhen; Zhou, Jianmin

    2015-01-01

    Controlled-release fertilizers (CRF) use a controlled-release technology to enhance the nutrient use efficiency of crops. Many factors affect the release of nutrients from the waterborne polymer-coated CRF, but the effects of thermal post-treatments remain unclear. In this study, a waterborne polyacrylate-coated CRF was post-treated at different temperatures (30 °C, 60 °C, and 80 °C) and durations (2, 4, 8, 12, and 24 h) after being developed in the Wurster fluidized bed. To characterize the polyacrylate membrane, and hence to analyze the mechanism of nutrient release, Fourier transform mid-infrared spectroscopy, scanning electron microscopy, and atomic force microscopy were employed. The nutrient-release model of CRF post-treated at 30 °C was the inverse “L” curve, but an increased duration of the post-treatment had no effect. The nutrient-release model was “S” curve and nutrient-release period was enhanced at higher post-treatment temperatures, and increased post-treatment duration lengthened slowed nutrient release due to a more compact membrane and a smoother membrane surface as well as a promoted crosslinking action. CRF equipped with specified nutrient-release behaviors can be achieved by optimizing the thermal post-treatment parameters, which can contribute to the development and application of waterborne polymer-coated CRF and controlled-release technologies. PMID:26348791

  16. Thermal post-treatment alters nutrient release from a controlled-release fertilizer coated with a waterborne polymer.

    PubMed

    Zhou, Zijun; Du, Changwen; Li, Ting; Shen, Yazhen; Zhou, Jianmin

    2015-09-08

    Controlled-release fertilizers (CRF) use a controlled-release technology to enhance the nutrient use efficiency of crops. Many factors affect the release of nutrients from the waterborne polymer-coated CRF, but the effects of thermal post-treatments remain unclear. In this study, a waterborne polyacrylate-coated CRF was post-treated at different temperatures (30 °C, 60 °C, and 80 °C) and durations (2, 4, 8, 12, and 24 h) after being developed in the Wurster fluidized bed. To characterize the polyacrylate membrane, and hence to analyze the mechanism of nutrient release, Fourier transform mid-infrared spectroscopy, scanning electron microscopy, and atomic force microscopy were employed. The nutrient-release model of CRF post-treated at 30 °C was the inverse "L" curve, but an increased duration of the post-treatment had no effect. The nutrient-release model was "S" curve and nutrient-release period was enhanced at higher post-treatment temperatures, and increased post-treatment duration lengthened slowed nutrient release due to a more compact membrane and a smoother membrane surface as well as a promoted crosslinking action. CRF equipped with specified nutrient-release behaviors can be achieved by optimizing the thermal post-treatment parameters, which can contribute to the development and application of waterborne polymer-coated CRF and controlled-release technologies.

  17. Thermal post-treatment alters nutrient release from a controlled-release fertilizer coated with a waterborne polymer

    NASA Astrophysics Data System (ADS)

    Zhou, Zijun; Du, Changwen; Li, Ting; Shen, Yazhen; Zhou, Jianmin

    2015-09-01

    Controlled-release fertilizers (CRF) use a controlled-release technology to enhance the nutrient use efficiency of crops. Many factors affect the release of nutrients from the waterborne polymer-coated CRF, but the effects of thermal post-treatments remain unclear. In this study, a waterborne polyacrylate-coated CRF was post-treated at different temperatures (30 °C, 60 °C, and 80 °C) and durations (2, 4, 8, 12, and 24 h) after being developed in the Wurster fluidized bed. To characterize the polyacrylate membrane, and hence to analyze the mechanism of nutrient release, Fourier transform mid-infrared spectroscopy, scanning electron microscopy, and atomic force microscopy were employed. The nutrient-release model of CRF post-treated at 30 °C was the inverse “L” curve, but an increased duration of the post-treatment had no effect. The nutrient-release model was “S” curve and nutrient-release period was enhanced at higher post-treatment temperatures, and increased post-treatment duration lengthened slowed nutrient release due to a more compact membrane and a smoother membrane surface as well as a promoted crosslinking action. CRF equipped with specified nutrient-release behaviors can be achieved by optimizing the thermal post-treatment parameters, which can contribute to the development and application of waterborne polymer-coated CRF and controlled-release technologies.

  18. Recommended for release on recognizance: factors affecting pretrial release recommendations.

    PubMed

    Petee, T A

    1994-06-01

    Researchers have acknowledged the influence of pretrial release agencies in judicial decision making regarding bail; however, few researchers have focused on the process used by the pretrial release agencies to make bail-bond recommendations. In this study I sought to establish which factors were most salient in making the decision to recommend a defendant for release on recognizance. I found that both officially sanctioned release criteria and "extralegal" variables were predictive of this decision.

  19. Sustained-release, extended-release, and other time-release formulations in neuropsychiatry.

    PubMed

    Andrade, Chittaranjan

    2015-08-01

    Pills and capsules may release their contents within minutes of ingestion; these are immediate-release formulations. Pills and capsules may also release their contents after a time lag, or a little at a time, or in some other predetermined way; these are time-release formulations. Many drugs in psychiatry have been time-release formulated to reduce their local adverse effects in the gastrointestinal tract, to reduce adverse effects associated with peak blood levels, or to artificially extend their half-life. Time-release formulations are associated with the added advantages of convenience of dosing, improved compliance, and less fluctuation in blood levels across the course of the day. A disadvantage of time-release formulations is that they may be incompletely absorbed; this is a serious issue in patients with acute or chronic intestinal hurry disorders, such as gastroenteritis or irritable bowel syndrome. Time-release formulations may also be more expensive than immediate-release formulations.

  20. Gas releases from salt

    SciTech Connect

    Ehgartner, B.; Neal, J.; Hinkebein, T.

    1998-06-01

    The occurrence of gas in salt mines and caverns has presented some serious problems to facility operators. Salt mines have long experienced sudden, usually unexpected expulsions of gas and salt from a production face, commonly known as outbursts. Outbursts can release over one million cubic feet of methane and fractured salt, and are responsible for the lives of numerous miners and explosions. Equipment, production time, and even entire mines have been lost due to outbursts. An outburst creates a cornucopian shaped hole that can reach heights of several hundred feet. The potential occurrence of outbursts must be factored into mine design and mining methods. In caverns, the occurrence of outbursts and steady infiltration of gas into stored product can effect the quality of the product, particularly over the long-term, and in some cases renders the product unusable as is or difficult to transport. Gas has also been known to collect in the roof traps of caverns resulting in safety and operational concerns. The intent of this paper is to summarize the existing knowledge on gas releases from salt. The compiled information can provide a better understanding of the phenomena and gain insight into the causative mechanisms that, once established, can help mitigate the variety of problems associated with gas releases from salt. Outbursts, as documented in mines, are discussed first. This is followed by a discussion of the relatively slow gas infiltration into stored crude oil, as observed and modeled in the caverns of the US Strategic Petroleum Reserve. A model that predicts outburst pressure kicks in caverns is also discussed.

  1. Mental Health Issues of Women After Release From Jail and Prison: A Systematic Review.

    PubMed

    Stanton, Ann E; Kako, Peninnah; Sawin, Kathleen J

    2016-05-01

    The aim of this review article is to gain an understanding of the mental health issues of women released from jail or prison. Thirty-six studies were synthesized using the biopsychosocial model. Results indicate that released women's mental health issues include psychiatric diagnoses, psychological trauma, substance use disorders; access to psychological medications and services; and motherhood challenges, support, access to basic needs, and criminalized behaviors. Nurses can promote released women's mental health through pre-release assessment and treatment of mental health issues and ensuring access to post-release resources.  Future research should examine released women's mental health experiences.

  2. Shock compression and quasielastic release in tantalum

    SciTech Connect

    Johnson, J.N.; Hixson, R.S.; Tonks, D.L.; Gray, G.T. III

    1993-06-01

    Previous studies of quasielastic release in shock-loaded FCC metals have shown a strong influence of the defect state on the leading edge, or first observable arrival, of release wave, due to large density of pinned dislocation segments behind the shock front, their relatively large pinning separation, and a very short response time as determined by drag coefficient in shock-compressed state. This effect is entirely equivalent to problems associated with elastic moduli determination using ultrasonic methods. This is particularly true for FCC metals, which have an especially low Peierls stress, or inherent lattice resistance, that has little influence in pinning dislocation segments and inhibiting anelastic deformation. BCC metals, on the other hand, have a large Peierls stress that essentially holds dislocation segments in place at low net applied shear stresses and thus allows fully elastic deformation to occur in the complete absence of anelastic behavior. Shock-compression and release experiments have been performed on tantalum (BCC), with the observation that the leading release disturbance is indeed elastic. This conclusion is established by examination of experimental VISAR records taken at the tantalum/sapphire (window) interface in a symmetric-impact experiment which subjects the sample to a peak longitudinal stress of approximately 7.3 GPa, in comparison with characteristic code calculations.

  3. CONTROLLING BEHAVIOR CHANGERS' BEHAVIOR.

    ERIC Educational Resources Information Center

    MARKLE, DAVID G.

    AN EMERGING METHODOLOGY OF PROGRAMING AVOIDS SOME OF THE UNFORTUNATE EFFECTS ON PROGRAMER BEHAVIOR PRODUCED BY INTERPRETATIONS OF TWO EARLIER METHODOLOGIES. WHILE SKINNERIAN PROGRAMING OFTEN HAS LED TO TRIVIAL PROGRAMS THROUGH PROBLEMS OF APPLICATION OF THE CRITERIA OF SPECIFIED BEHAVIORAL OBJECTIVES AND LOW ERROR RATES, CROWDERIAN PROGRAMING HAS…

  4. Optimal advanced credit releases in ecosystem service markets.

    PubMed

    BenDor, Todd K; Guo, Tianshu; Yates, Andrew J

    2014-03-01

    Ecosystem service markets are popular policy tools for ecosystem protection. Advanced credit releases are an important factor affecting the supply side of ecosystem markets. Under an advanced credit release policy, regulators give ecosystem suppliers a fraction of the total ecosystem credits generated by a restoration project before it is verified that the project actually achieves the required ecological thresholds. In spite of their prominent role in ecosystem markets, there is virtually no regulatory or research literature on the proper design of advanced credit release policies. Using U.S. aquatic ecosystem markets as an example, we develop a principal-agent model of the behavior of regulators and wetland/stream mitigation bankers to determine and explore the optimal degree of advance credit release. The model highlights the tension between regulators' desire to induce market participation, while at the same time ensuring that bankers successfully complete ecological restoration. Our findings suggest several simple guidelines for strengthening advanced credit release policy.

  5. Optimal Advanced Credit Releases in Ecosystem Service Markets

    NASA Astrophysics Data System (ADS)

    BenDor, Todd K.; Guo, Tianshu; Yates, Andrew J.

    2014-03-01

    Ecosystem service markets are popular policy tools for ecosystem protection. Advanced credit releases are an important factor affecting the supply side of ecosystem markets. Under an advanced credit release policy, regulators give ecosystem suppliers a fraction of the total ecosystem credits generated by a restoration project before it is verified that the project actually achieves the required ecological thresholds. In spite of their prominent role in ecosystem markets, there is virtually no regulatory or research literature on the proper design of advanced credit release policies. Using U.S. aquatic ecosystem markets as an example, we develop a principal-agent model of the behavior of regulators and wetland/stream mitigation bankers to determine and explore the optimal degree of advance credit release. The model highlights the tension between regulators' desire to induce market participation, while at the same time ensuring that bankers successfully complete ecological restoration. Our findings suggest several simple guidelines for strengthening advanced credit release policy.

  6. Alternate polyelectrolyte coating of chitosan beads for extending drug release.

    PubMed

    Srinatha, A; Pandit, Jayanta K

    2008-01-01

    In the present study, we addressed the factors modifying ciprofloxacin release from multiple coated beads. Beads were prepared by simple ionic cross-linking with sodium tripolyphoshate and coated with alginate and/or chitosan to prepare single, double, or multilayered beads. The water uptake capacity depended on the nature of beads (coated or uncoated) and pH of test medium. The number of coatings given to the beads influenced ciprofloxacin release rate. The coating significantly decreased the drug release from the beads in comparison to uncoated beads (p < 0.001). When the beads were given three coatings, viz., alginate, chitosan, and again alginate, the drug release appeared to follow the pattern exhibited by colon-targeted drug delivery systems with time dependent release behavior. The increase in coating formed a barrier for easy ingress of dissolution medium into the bead matrix, reducing the diffusion of drug.

  7. A New Understanding of Chemical Agent Release

    SciTech Connect

    Nakafuji, G; Greenman, R; Theofanous, T

    2002-07-24

    The evolution of thickened chemical agent released at supersonic velocities, due to a missile defense intercept or a properly functioning warhead, has been misunderstood. Current and historical experimental and modeling efforts have attributed agent breakup to a variety of droplet breakup mechanisms. According to this model, drops of agent fragment into subsequent generations of smaller drops until a stable drop size is reached. Recent experimental data conducted in a supersonic wind tunnel show that agent breakup is not driven by any droplet breakup mechanism. The breakup of agent is instead governed by viscoelastic behavior and aerodynamic history effects. This viscoelastic breakup mechanism results in the formation of threads and sheets of liquid, instead of drops. The evolution and final state of agent released has broad implications not only for aerobreakup models, but also for all atmospheric dispersion models.

  8. Release kinetics of highly porous floating tablets containing cilostazol.

    PubMed

    Hwang, Kyu-Mok; Cho, Cheol-Hee; Tung, Nguyen-Thach; Kim, Ju-Young; Rhee, Yun-Seok; Park, Eun-Seok

    2017-02-20

    This study focuses on developing a highly porous floating tablet containing cilostazol. The underlying release mechanism of cilostazol from porous and floating tablets in dissolution media containing surfactants was investigated. The tablets were prepared by compressing granules and excipients with a sublimating agent, followed by sublimation under vacuum. The volatile material for the sublimating agent was chosen based on its flow properties using conventional methods as well as the twisted blade method. Resultant tablets could float immediately and had significantly higher tensile strengths than conventional tablets of similar porosities, holding a promising potential for increasing gastroretentive properties. Fitting the release profiles to the Korsmeyer-Peppas equation indicated Super Case II, Case II and non-Fickian kinetics, which implied that the release was affected by both floating behavior and matrix erosion. Abrupt changes in release kinetic parameters and erosional behaviors were found between the tablets containing different amounts of HPMC, indicating the existence of an excipient percolation threshold. Neither the surfactant in the media nor the porosity affected the dominant release mechanism, which was matrix erosion. Understanding the dominant release mechanism and percolation threshold allows for tuning the formulation to obtain various release profiles.

  9. [Compound erythromycin sustained release preparation and its in vitro release].

    PubMed

    Chen, Hai-xia; Chen, Zhi-peng; Wang, Qi-rong; Liu, Ze-kun; Ma, Quan-long

    2011-11-01

    Using the weight-average molecular weight 50 000 polylactic acid (PLA) as a carrier, and a certain proportion of erythromycin (EM) and prednisone acetate (PNA) to mixed prepare the compound erythromycin sustained release preparation (sustained-release tablets). Using ultraviolet spectrophotometry and high performance liquid chromatography (HPLC) to detect separately the release amount of EM and PNA in vitro medium. The sustained-release tablets release for about 21 days, the average content of EM is 99.7 mg/table, RSD = 0.82%; and the average content of PNA is 10.03 mg/table, RSD = 0.93%. Within 21 days, the cumulative releases of EM and PNA are 86.1% and 78.3%, respectively. The drug release is steady and slow after 5 days, the burst release phenomenon in early stage is more significant. The results showed that the sustained-release tablet preparation method is feasible, the release performance is good and the clinical efficacy is significant.

  10. QUICK RELEASABLE DRIVE

    DOEpatents

    Dickson, J.J.

    1958-07-01

    A quick releasable mechanical drive system suitable for use in a nuclear reactor is described. A small reversible motor positions a control rod by means of a worm and gear speed reducer, a magnetic torque clutch, and a bell crank. As the control rod is raised to the operating position, a heavy coil spring is compressed. In the event of an emergency indicated by either a''scram'' signal or a power failure, the current to the magnetic clutch is cut off, thereby freeing the coil spring and the bell crank positioner from the motor and speed reduction gearing. The coil spring will immediately act upon the bell crank to cause the insertion of the control rod. This arrangement will allow the slow, accurate positioning of the control rod during reactor operation, while providing an independent force to rapidly insert the rod in the event of an emergency.

  11. Quick release engine cylinder

    DOEpatents

    Sunnarborg, Duane A.

    2000-01-01

    A quick release engine cylinder allows optical access to an essentially unaltered combustion chamber, is suitable for use with actual combustion processes, and is amenable to rapid and repeated disassembly and cleaning. A cylinder member, adapted to constrain a piston to a defined path through the cylinder member, sealingly engages a cylinder head to provide a production-like combustion chamber. A support member mounts with the cylinder member. The support-to-cylinder mounting allows two relationships therebetween. In the first mounting relationship, the support engages the cylinder member and restrains the cylinder against the head. In the second mounting relationship, the cylinder member can pass through the support member, moving away from the head and providing access to the piston-top and head.

  12. SITELLE's Data Release 1

    NASA Astrophysics Data System (ADS)

    Martin, T. B.; Drissen, L.

    2016-12-01

    Installed at the Canada-France-Hawaii Telescope (CFHT) since August 2015, SITELLE is an Imaging Fourier Transform Spectrometer (IFTS) with an 11×11 field of view. After its prototype SpIOMM, installed at Mont Mégantic (Québec, Canada), it is the second IFTS in the world operating in the visible band (350-1000 nm). It delivers hyperspectral data cubes of 4 million spectra at R˜1500-5000 with a spatial sampling of 0.32" and a filling factor of 100 %. A suite of softwares has been designed to reduce (ORBS) and analyze (ORCS) the data. Based on commissioning data obtained in August 2015, a first stable version has been released in March 2016 which is capable of reducing all the data. In this paper the quality of the calibration is discussed.

  13. Controlled Release of Imidacloprid from Poly Styrene-Diacetone - Nanoformulation

    NASA Astrophysics Data System (ADS)

    Qian, Kun; Guo, Yanzhen; He, Lin

    2012-01-01

    Imidacloprid is a neonicotinoids insecticide, which is important for the cash crops such as tomato, rape and so on. The conventional formulation does not only increase the loss of pesticide but also leads to environmental pollution. Controlled-release formulations of pesticide are highly desirable not only for attaining the most effective utilization of the pesticide, but also for reducing environmental pollution. Pesticide imidacloprid was incorporated in poly (styrene-diacetone crylamide)-based formulation to obtain controlled release properties, and the imidacloprid nanocontrolled release formulation was characterized by infrared (IR) and field emission scanning electron microscope (FESEM). Factors related to loading efficiency, swelling and release behaviors of the formulation were investigated. It showed that the loading efficiency could reach about 40% (w/w). The values for the diffusion exponent "n" were in the range of 0.31-0.58, which indicated that the release of imidacloprid was diffusion-controlled. The time taken for 50% of the active ingredient to be released into water, T50, was also calculated for the comparison of formulations in different conditions. The results showed that the formulation with higher temperature and more diacetone crylamide had lower value of T50, which means a quicker release of the active ingredient. This study highlighted some pieces of evidence that improved pesticide incorporation and slower release were linked to potential interactions between the pesticide and the polymer.

  14. Optogenetic control of ATP release

    NASA Astrophysics Data System (ADS)

    Lewis, Matthew A.; Joshi, Bipin; Gu, Ling; Feranchak, Andrew; Mohanty, Samarendra K.

    2013-03-01

    Controlled release of ATP can be used for understanding extracellular purinergic signaling. While coarse mechanical forces and hypotonic stimulation have been utilized in the past to initiate ATP release from cells, these methods are neither spatially accurate nor temporally precise. Further, these methods cannot be utilized in a highly effective cell-specific manner. To mitigate the uncertainties regarding cellular-specificity and spatio-temporal release of ATP, we herein demonstrate use of optogenetics for ATP release. ATP release in response to optogenetic stimulation was monitored by Luciferin-Luciferase assay (North American firefly, photinus pyralis) using luminometer as well as mesoscopic bioluminescence imaging. Our result demonstrates repetitive release of ATP subsequent to optogenetic stimulation. It is thus feasible that purinergic signaling can be directly detected via imaging if the stimulus can be confined to single cell or in a spatially-defined group of cells. This study opens up new avenue to interrogate the mechanisms of purinergic signaling.

  15. Synthesis of copper nanostructures on silica-based particles for antimicrobial organic coatings

    NASA Astrophysics Data System (ADS)

    Palza, Humberto; Delgado, Katherine; Curotto, Nicolás

    2015-12-01

    Sol-gel based silica nanoparticles of 100 nm were used to interact with copper ions from the dissolution of CuCl2 allowing the synthesis of paratacamite (Cu2(OH)3Cl) nanocrystals of around 20 nm. The method produced well dispersed copper nanostructures directly supported on the surface of the SiO2 particles and was generalized by using a natural zeolite microparticle as support with similar results. These hybrid Cu based nanoparticles released copper ions when immersed in water explaining their antimicrobial behavior against Escherichia coli and Staphylococcus aureus as measured by the minimum inhibitory and minimum bactericidal concentrations (MIC and MBC). Noteworthy, when these nanostructured particles were mixed with an organic coating the resulting film eliminated until a 99% of both bacteria at concentrations as low as 0.01 wt%.

  16. Prediction of modified release pharmacokinetics and pharmacodynamics from in vitro, immediate release, and intravenous data.

    PubMed

    Lukacova, Viera; Woltosz, Walter S; Bolger, Michael B

    2009-06-01

    The aim of this study was to demonstrate the value of mechanistic simulations in gaining insight into the behaviors of modified release (MR) formulations in vivo and to use the properly calibrated models for prediction of pharmacokinetics (PK) and pharmacodynamics (PD). GastroPlus (Simulations Plus, Inc.) was used to fit mechanistic models for adinazolam and metoprolol that describe the absorption, PK, and PD after intravenous (i.v.) and immediate release (IR) oral (p.o.) administration. The fitted model for adinazolam was then used to predict the PD profile for a MR formulation and to design a new formulation with desired onset and duration of action. The fitted metoprolol model was used to gain insight and to explain the in vivo behaviors of MR formulations. For each drug, a single absorption/PK model was fitted that provided simulated plasma concentration-time profiles closely matching observed in vivo profiles across several different i.v. and p.o doses. Sedation score profiles of adinazolam were fitted with an indirect PD model. For metoprolol, the fitted absorption/PK model for IR p.o. doses was used to select in vitro dissolution conditions that best matched the in vivo release of MR doses. This model also explained differences in exposure after administration of MR formulations with different release rates. Mechanistic absorption/PK models allow for detailed descriptions of all processes affecting the two drugs' bioavailability, including release/dissolution, absorption, and intestinal and hepatic first pass extraction. The insights gained can be used to design formulations that more effectively overcome identified problems.

  17. In vitro release of metoclopramide from hydrophobic matrix tablets. influence of hydrodynamic conditions on kinetic release parameters.

    PubMed

    Frutos, P; Pabón, C; Lastres, J L; Frutos, G

    2001-10-01

    There has been growing interest in the subject of drug delivery and the design and evaluation of controlled-release systems. The simplest way to control the release of an active agent is to disperse it in an inert polymeric matrix. Controlled-release systems are of interest because they are technologically simple, relatively cheap, and practically unaffected by physiological changes. In this study, a new matrix system was formed by an active principle, metoclopramide hydrochloride, scattered into a biocompatible hydrophobic polymerical mesh, polyamide 12, to achieve sustained and controlled delivery of metoclopramide hydrochloride. This research was conducted to investigate the in vitro drug release behavior from these new inert polymeric matrix tablets. The drug release process was investigated both experimentally and by means of mathematical models. Different models were applied for the evaluation of drug release data. On the basis of our results, a biexponential equation was proposed, Q=Qfast(1)(1 - e(-Kfast t)) + Qslow(2)(1 - e(-Kslow t)), in an attempt to explain the mechanism responsible for the release process. Additionally, the influence of the experimental conditions of the dissolution devices, such as rate of flow and pH of dissolution medium, on the parameters that characterize the release mechanism was studied, and it was found that the main factor was the hydrodynamic condition of rate of flow.

  18. Thermal-induced force release in oxyhemoglobin

    PubMed Central

    Gevorkian, S. G.; Allahverdyan, A. E.; Gevorgyan, D. S.; Hu, Chin-Kun

    2015-01-01

    Oxygen is released to living tissues via conformational changes of hemoglobin from R-state (oxyhemoglobin) to T-state (desoxyhemoglobin). The detailed mechanism of this process is not yet fully understood. We have carried out micromechanical experiments on oxyhemoglobin crystals to determine the behavior of the Young’s modulus and the internal friction for temperatures between 20 °C and 70 °C. We have found that around 49 °C oxyhemoglobin crystal samples undergo a sudden and strong increase of their Young’s modulus, accompanied by a sudden decrease of the internal friction. This sudden mechanical change (and the ensuing force release) takes place in a partially unfolded state and precedes the full denaturation transition at higher temperatures. After this transformation, the hemoglobin crystals have the same mechanical properties as their initial state at room temperatures. We conjecture that it can be relevant for explaining the oxygen-releasing function of native oxyhemoglobin when the temperature is increased, e.g. due to active sport. The effect is specific for the quaternary structure of hemoglobin, and is absent for myoglobin with only one peptide sequence. PMID:26277901

  19. Dynamics of a barium release in the magnetospheric tail

    NASA Technical Reports Server (NTRS)

    Mende, S. B.; Swenson, G. R.; Geller, S. P.; Doolittle, J. H.; Haerendel, G.

    1989-01-01

    The late time behavior of the May 13, 1985 magnetotail barium cloud is examined. The bulk dynamics of the cloud are studied based on triangulated data and data from Fabry-Perot Doppler velocity measurements. The changes in cloud morphology in relation to the in situ measurements made by the Ion Release Module satellite are discussed.

  20. Using Randomized Controlled Trials to Evaluate Interventions for Releasing Prisoners

    ERIC Educational Resources Information Center

    Pettus-Davis, Carrie; Howard, Matthew Owen; Dunnigan, Allison; Scheyett, Anna M.; Roberts-Lewis, Amelia

    2016-01-01

    Randomized controlled trials (RCTs) are rarely used to evaluate social and behavioral interventions designed for releasing prisoners. Objective: We use a pilot RCT of a social support intervention (Support Matters) as a case example to discuss obstacles and strategies for conducting RCT intervention evaluations that span prison and community…

  1. Cortisol Release in Infants in Response to Inoculation.

    ERIC Educational Resources Information Center

    Lewis, Michael; Thomas, David

    1990-01-01

    Data provide strong evidence that studies of stress and cortisol release in infants must take into account basal level, circadian rhythm, and behavioral effects and employ appropriate statistical procedures. Participants were infants of two, four, and six months of age from whom salivary cortisol was obtained before and 15 minutes after an…

  2. Central corticotropin releasing factor and social stress

    PubMed Central

    Backström, Tobias; Winberg, Svante

    2013-01-01

    Social interactions are a main source of stress in vertebrates. Social stressors, as well as other stressors, activate the hypothalamic–pituitary–adrenal (HPA) axis resulting in glucocorticoid release. One of the main components of the HPA axis is corticotropin releasing factor (CRF). The neuropeptide CRF is part of a peptide family including CRF, urocortin 1–3, urotensin 1–3, and sauvagine. The actions of the CRF family are mediated by at least two different receptors with different anatomical distribution and affinities for the peptides. The CRF peptides affect several behavioral and physiological responses to stress including aggression, feeding, and locomotor activity. This review will summarize recent research in vertebrates concerning how social stress interacts with components of the CRF system. Consideration will be taken to the different models used for social stress ranging from social isolation, dyadic interactions, to group dominance hierarchies. Further, the temporal effect of social stressor from acute, intermittent, to chronic will be considered. Finally, strains selected for specific behavior or physiology linked to social stress will also be discussed. PMID:23847465

  3. Sodium lauryl sulfate impedes drug release from zinc-crosslinked alginate beads: switching from enteric coating release into biphasic profiles.

    PubMed

    Taha, Mutasem O; Nasser, Wissam; Ardakani, Adel; Alkhatib, Hatim S

    2008-02-28

    The aim of this research is to investigate the effects of sodium lauryl sulfate (SLS) on ionotropically cross-linked alginate beads. Different levels of SLS were mixed with sodium alginate and chlorpheniramine maleate (as loaded model drug). The resulting viscous solutions were dropped onto aqueous solutions of zinc or calcium ions for ionotropic curing. The generated beads were assessed by their drug releasing profiles, infrared and differential scanning colorimetery (DSC) traits. SLS was found to exert profound concentration-dependent impacts on the characteristics of zinc-crosslinked alginate beads such that moderate modifications in the levels of SLS switched drug release from enteric coating-like behavior to a biphasic release modifiable to sustained-release by the addition of minute amounts of xan