Sample records for biguanide derivatives chemical

  1. [Biguanide].

    PubMed

    Ohta, Akio; Tanaka, Yasushi

    2015-03-01

    Metformin, a biguanide, is considered in EASD and ADA to be a first-line glucose-lowering agent for patients with type 2 diabetes. The effectiveness of metformin as an anti-diabetic drug is explained by its ability to lower blood glucose by decreasing hepatic glucose production, stimulating glucose uptake in the muscle, and increasing fatty acid oxidation in adipose tissue. The exact mechanism of this effect has not been fully understood, but metformin is thought to activate hepatic AMP-activated protein kinase (AMPK), and it suppresses liver glucagon signal by increasing AMP due to inhibition of mitochondrial respiratory complex I. Caution is advised to avoid use of metformin in patients at risk for lactic acidosis (e.g., in patients with advanced renal and liver insufficiency, infection, dehydration, alcoholism, or in those using diuretics or SGLT2 inhibitor). PMID:25812364

  2. Crystal Spectrum of Copper Biguanides

    Microsoft Academic Search

    Animesh Chakravorty; Sadhan Basu

    1960-01-01

    IN a previous communication1 it was shown that the absorption spectrum of a microscopic crystal of copper-ethylene- diamine-bis(acetylacetone) consists of three bands as predicted by the ligand field theory. Copper biguanides form transparent reddish crystals2, very convenient for measurement in our experimental arrangement. In Fig. 1 are given the spectrophotometric optical density (O.D.) vs. wave-length (lambda) curves for a thin

  3. Environmental fate of polyhexamethylene biguanide.

    PubMed

    Lucas, Anne D

    2012-03-01

    Polyhexamethylene biguanide (PHMB) is used as a bacteriocidal agent in a variety of applications from medical devices to pools, but is highly toxic to some aquatic species. The stability of PHMB in various environmental matrices was examined. 80% of PHMB was present in fortified creek samples after 20 days, but bound immediately to soils with the exception of sandy soil. PHMB was absorbed to below detectable levels by weathered concrete within 12 h. In addition, one over the counter wound care product containing PHMB was evaluated to assess environmental leaching; detectable levels (20 ?g/mL) were still present after 1 week. PMID:22037631

  4. Potential applications for biguanides in oncology

    PubMed Central

    Pollak, Michael

    2013-01-01

    Metformin is widely prescribed for the treatment of type II diabetes. Recently, it has been proposed that this compound or related biguanides may have antineoplastic activity. Biguanides may exploit specific metabolic vulnerabilities of transformed cells by acting on them directly, or may act by indirect mechanisms that involve alterations of the host environment. Preclinical data suggest that drug exposure levels are a key determinant of proposed direct actions. With respect to indirect mechanisms, it will be important to determine whether recently demonstrated metformin-induced changes in levels of candidate systemic mediators such as insulin or inflammatory cytokines are of sufficient magnitude to achieve therapeutic benefit. Results of the first generation of clinical trials now in progress are eagerly anticipated. Ongoing investigations may justify a second generation of trials that explore pharmacokinetic optimization, rational drug combinations, synthetic lethality strategies, novel biguanides, and the use of predictive biomarkers. PMID:23999444

  5. Polyhexamethylene biguanide dressings in wound management.

    PubMed

    Fumarola, Sian

    This article describes wound management using polyhexamethylene biguanide dressings in two patients experiencing multiple comorbidities. Wound bed debridement and bioburden management were important factors in achieving positive results in terms of promoting wound healing and reducing infection and malodour. PMID:21894678

  6. The effect of reactive dyes upon the uptake and anti bacterial action of poly(hexamethylene biguanide) on cotton. Part 2: Uptake of poly(hexamethylene biguanide) on cotton dyed with ?-sulphatoethylsulphonyl reactive dyes

    Microsoft Academic Search

    A. Kawabata; J. A. Taylor

    2006-01-01

    Polyhexamethylene biguanide (PHMB) is a widely used bacteriocide. It is marketed as an aqueous solution of its hydrochloride from which it is readily adsorbed onto cotton, this process depending upon the ability of the cationic PHMB to form electrostatic links with the anionic carboxylate groups present on cotton. The introduction of chemically bound sulphonic acid groups into cotton, which takes

  7. Practical Chemical Sensors from Chemically Derived Graphene

    Microsoft Academic Search

    Jesse D. Fowler; Matthew J. Allen; Vincent C. Tung; Yang Yang; Richard B. Kaner; Bruce H. Weiller

    2009-01-01

    We report the development of useful chemical sensors from chemically converted graphene dispersions using spin coating to create single-layer films on interdigitated electrode arrays. Dispersions of graphene in anhydrous hydrazine are formed from graphite oxide. Preliminary results are presented on the detection of NO2,NH3, and 2,4-dinitrotoluene using this simple and scalable fabrication method for practical devices. Currentversusvoltage curves are linear

  8. Chemical derivatives of castor oil

    Microsoft Academic Search

    K. T. Achaya

    1971-01-01

    The chemistry of castor oil and its derivatives is reviewed with particular reference to work done in India in general and\\u000a at the Regional Research Laboratory in Hyderabad in particular. Topics covered are the structure of castor oil, preparation\\u000a of ricinoleic acid and its glycerides, monoglycerides, surfactants from castor oil, diverse hydrogenations, dehydration, preparation\\u000a and properties of estolides, alkali fusion

  9. Chemically Derived, Ultrasmooth Graphene Nanoribbon Semiconductors

    Microsoft Academic Search

    Xiaolin Li; Xinran Wang; Li Zhang; Sangwon Lee; Hongjie Dai

    2008-01-01

    We developed a chemical route to produce graphene nanoribbons (GNR) with width below 10 nanometers, as well as single ribbons with varying widths along their lengths or containing lattice-defined graphene junctions for potential molecular electronics. The GNRs were solution-phase derived, stably suspended in solvents with noncovalent polymer functionalization, and exhibited ultrasmooth edges with possibly well-defined zigzag or armchair-edge structures. Electrical

  10. Production of Chemical Derivatives from Renewables

    SciTech Connect

    Davison, Brian; Nghiem, John; Donnelly, Mark; Tsai, Shih-Perng; Frye, John; Landucci, Ron; Griffin, Michael

    1996-06-01

    The purpose of this Cooperative Research and Development Agreement (CRADA) between Lockheed Martin Energy Research Corp., (LMER), Argonne National Laboratory (ANL), National Renewable Energy Laboratory (NREL), and Battelle Memorial Institute, operator of Pacific Northwest National Laboratory (PNNL), (collectively referred to as the 'Contractor'), and Applied Carbochemicals, Inc. (Participant) was to scale-up from bench results an economically promising and competitive process for the production of chemical derivatives from biologically produced succinic acid. The products that were under consideration for production from the succinic acid platform included 1,4-butanediol, {gamma}y-butyrolactone, 2-pyrrolidinone and N-methyl pyrrolidinone. Preliminary economic analyses indicated that this platform was competitive with the most recent petrochemical routes. The Contractors and participant are hereinafter jointly referred to as the 'Parties.' Research to date in succinic acid fermentation, separation and genetic engineering resulted in a potentially economical process based on the use of an Escherichia coli strain AFP111 with suitable characteristics for the production of succinic acid from glucose. Economic analysis has shown that higher value commodity chemicals can be economically produced from succinic acid based on preliminary laboratory findings and predicted catalytic parameters. At the time, the current need was to provide the necessary laboratory follow-up information to properly optimize, design and operate a pilot scale process. The purpose of the pilot work was to validate the integrated process, assure 'robustness' of the process, define operating conditions, and provide samples for potential customer evaluation. The data from the pilot scale process was used in design and development of a full scale production facility. A new strain, AFP111 (patented), discovered at ANL was tested and developed for process use at the Oak Ridge National Laboratory (ORNL) and ANL. The operability and product formation are attractive for this strain and effort was being directed at process development and optimization. Key to the transition from the fermentative production unit operation to the chemical catalysis is the 'clean-up' of fermentation broth, succinic acid formation from the salt, and succinic acid concentration. These steps are accomplished by a two-stage membrane ED separation process developed at AWL. Although the current process is well developed, possible modifications and optimization may be called for as development work continues in both the fermentation and catalysis areas. Research to date performed at PNNL has demonstrated that succinic acid can be converted to value added chemicals such as 1,4-butanediol, {gamma}-butyrolactone, N-methyl pyrrolidinone, and 2 pyrrolidinone with high conversion and selectivities. Continued research will be performed in catalyst development and reaction condition optimization to move this work from the bench scale to the pilot scale. All development of the process was guided by the NREL technoeconomic model. The model showed that direct aqueous phase catalysis of succinic acid to 1,4-butanediol, {gamma}-butyrolactone, and N-methyl pyrrolidinone provided significant economical advantages in the market, the margin, and the return on capital investment over existing petrochemical processes for production of these compounds. The model also provided the baseline for evaluating current laboratory research. As data from the bench and pilot work were made available the model was modified and appropriate sensitivities ran to determine impact of the process changes and optimization. The report will present the planned CRADA tasks followed by the results. The results section has an overall project summary follwed by more detailed reports from the participants. This is a nonproprietary report; additional proprietary information may be made available subject to acceptance of the appropriate proprietary information agreements.

  11. Polyhexamethylene biguanide functionalized cationic silver nanoparticles for enhanced antimicrobial activity.

    PubMed

    Ashraf, Sumaira; Akhtar, Nasrin; Ghauri, Muhammad Afzal; Rajoka, Muhammad Ibrahim; Khalid, Zafar M; Hussain, Irshad

    2012-01-01

    Polyhexamethylene biguanide (PHMB), a broad spectrum disinfectant against many pathogens, was used as a stabilizing ligand for the synthesis of fairly uniform silver nanoparticles. The particles formed were characterized using UV-visible spectroscopy, FTIR, dynamic light scattering, electrophoretic mobility, and TEM to measure their morphology and surface chemistry. PHMB-functionalized silver nanoparticles were then evaluated for their antimicrobial activity against a gram-negative bacterial strain, Escherichia coli. These silver nanoparticles were found to have about 100 times higher bacteriostatic and bactericidal activities, compared to the previous reports, due to the combined antibacterial effect of silver nanoparticles and PHMB. In addition to other applications, PHMB-functionalized silver nanoparticles would be extremely useful in textile industry due to the strong interaction of PHMB with cellulose fabrics. PMID:22625664

  12. Double-Biguanide Therapy for Resistant Acanthamoeba Keratitis

    PubMed Central

    Ferrari, Giulio; Matuska, Stanislav; Rama, Paolo

    2011-01-01

    Aims To report the clinical and diagnostic findings of a patient with Acanthamoeba keratitis resistant to both polyhexamethylene biguanide (PHMB)-hexamidine and chlorhexidine-hexamidine treatment. Methods Slit-lamp biomicroscopy, corneal cell scraping and histopathology were performed on a 39-year-old woman presenting with corneal ulcer in her left eye. Results The patient was successfully treated with PHMB-chlorhexidine association therapy. Subsequent perforating keratoplasty remained clear at the last follow-up visit after 7 months and increased visual acuity to 20/20 with correction. Conclusions This case emphasizes the proteiform aspects of Acanthamoeba drug resistance, and suggests that PHMB-chlorhexidine association might represent an additional option for cases resistant to standard therapy. PMID:22174703

  13. Polyhexamethylene biguanide functionalized cationic silver nanoparticles for enhanced antimicrobial activity

    NASA Astrophysics Data System (ADS)

    Ashraf, Sumaira; Akhtar, Nasrin; Ghauri, Muhammad Afzal; Rajoka, Muhammad Ibrahim; Khalid, Zafar M.; Hussain, Irshad

    2012-05-01

    Polyhexamethylene biguanide (PHMB), a broad spectrum disinfectant against many pathogens, was used as a stabilizing ligand for the synthesis of fairly uniform silver nanoparticles. The particles formed were characterized using UV-visible spectroscopy, FTIR, dynamic light scattering, electrophoretic mobility, and TEM to measure their morphology and surface chemistry. PHMB-functionalized silver nanoparticles were then evaluated for their antimicrobial activity against a gram-negative bacterial strain, Escherichia coli. These silver nanoparticles were found to have about 100 times higher bacteriostatic and bactericidal activities, compared to the previous reports, due to the combined antibacterial effect of silver nanoparticles and PHMB. In addition to other applications, PHMB-functionalized silver nanoparticles would be extremely useful in textile industry due to the strong interaction of PHMB with cellulose fabrics.

  14. Study of epigenetic properties of Poly(HexaMethylene Biguanide) hydrochloride (PHMB).

    PubMed

    Creppy, Edmond E; Diallo, Aboudoulatif; Moukha, Serge; Eklu-Gadegbeku, Christophe; Cros, Daniel

    2014-08-01

    Poly(HexaMethylene Biguanide) hydrochloride (PHMB) CAS No. [32289-58-0] is a particularly effective member of the biguanides antiseptic chemical group, and has been in use since the early fifties in numerous applications. It has been proposed that PHMB be classified as a category 3 carcinogen although PHMB is not genotoxic. It has been hypothesized that PHMB may have epigenetic properties effects, including non-genotoxic modifications of DNA bases, DNA methylation and mitogenic cytokine production. These properties have been assessed in vitro using 3 cell types: Caco-2 cells (from a human colon adenocarcinoma) with a non-functional p53 gene. (?p53: mut p53), N2-A (Neuro-2A cells, mouse neural cells), the brain being a possible target organ in rodents and HepG2 cells (human hepatocellular carcinoma) with functional p53 gene. From the concentration 1 µg/mL up to 20 µg/mL of PHMB, no effect was observed, either growth stimulation or inhibition. Viability testing using neutral red led to an IC 50 of 20-25 µg/mL after treatment with PHMB for 3 h, whereas the MTT test led to IC50 values of 80 µg/mL, 160 µg/mL and 160 µg/mL respectively for HepG2 cells, Neuro-2A cells and Caco-2 cells. PHMB does not induce significant oxidative stress (production of MDA or lipoperoxidation, nor does it induce hydroxylation of DNA (8-OH-dG) and/or its hypermethylation (m5dC), the latter being strongly implicated in DNA replication and regulation and cell division. PHMB does not induce significant production of mitogenic cytokines such as TNF-? (tumor necrosis factor), interleukins (IL-1 alpha), and the transcription factor nuclear factor kappa B (NF-?B) which can cause either apoptosis or stimulate the growth of transformed cells or tumors. Instead, from concentrations of 20 to 100 µg/mL, PHMB kills cells of all types in less than 3 h. The expression of genes involved in the mechanisms of cell death induced by PHMB, including p53, the pro apoptotic gene bax and others, the anti-apoptotic bcl-2 and caspase-3 has been evaluated by RT-PCR. Finally, the status of GAP-junctions (GJIC) in the presence of PHMB has been determined and appeared to not be significantly affected. Taken together the data show that in vitro PHMB does not exhibit clear and remarkable epigenetic properties except a slight increase of some cytokines and transcription factor at higher concentrations at which cell lysis occurs rapidly. PMID:25111876

  15. Quantum chemical studies of some pyridine derivatives as corrosion inhibitors

    Microsoft Academic Search

    C Ö?retir; B Mihçi; G Bereket

    1999-01-01

    Quantum chemical study of the efficiency of some pyridine derivatives as corrosion inhibitors were performed by means of AM1, PM3, MINDO\\/3 and MNDO semi-empirical SCF molecular orbital methods. The agreement with the experimental data was found to be satisfactory.

  16. Revisiting the chemical reactivity indices as the state function derivatives. The role of classical chemical hardness

    NASA Astrophysics Data System (ADS)

    Malek, Ali; Balawender, Robert

    2015-02-01

    The chemical reactivity indices as the equilibrium state-function derivatives are revisited. They are obtained in terms of the central moments (fluctuation formulas). To analyze the role of the chemical hardness introduced by Pearson [J. Am. Chem. Soc. 105, 7512 (1983)], the relations between the derivatives up to the third-order and the central moments are obtained. As shown, the chemical hardness and the chemical potential are really the principal indices of the chemical reactivity theory. It is clear from the results presented here that the chemical hardness is not the derivative of the Mulliken chemical potential (this means also not the second derivative of the energy at zero-temperature limit). The conventional quadratic dependence of energy, observed at finite temperature, reduces to linear dependence on the electron number at zero-temperature limit. The chemical hardness plays a double role in the admixture of ionic states to the reference neutral state energy: it determines the amplitude of the admixture and regulates the damping of its thermal factor.

  17. Successful use of locally applied polyhexamethylene biguanide as an adjunct to the treatment of fungal osteomyelitis

    PubMed Central

    Walls, Genevieve; Noonan, Lisa; Wilson, Elizabeth; Holland, David; Briggs, Simon

    2013-01-01

    Fungal osteomyelitis is rare in immunocompetent patients and is often difficult to cure, even with optimal medical and surgical management. The authors present two cases of fungal osteomyelitis in which the common swimming pool cleaner, polyhexamethylene biguanide, was used successfully as an adjunct to standard surgical and medical treatment. Also presented is a literature review on the use of polyhexamethylene biguanide for this indication. The authors recommend that this safe and well-tolerated compound be considered as part of the treatment for fungal osteomyelitis. PMID:24421812

  18. Successful use of locally applied polyhexamethylene biguanide as an adjunct to the treatment of fungal osteomyelitis.

    PubMed

    Walls, Genevieve; Noonan, Lisa; Wilson, Elizabeth; Holland, David; Briggs, Simon

    2013-01-01

    Fungal osteomyelitis is rare in immunocompetent patients and is often difficult to cure, even with optimal medical and surgical management. The authors present two cases of fungal osteomyelitis in which the common swimming pool cleaner, polyhexamethylene biguanide, was used successfully as an adjunct to standard surgical and medical treatment. Also presented is a literature review on the use of polyhexamethylene biguanide for this indication. The authors recommend that this safe and well-tolerated compound be considered as part of the treatment for fungal osteomyelitis. PMID:24421812

  19. Marine derived polysaccharides for biomedical applications: chemical modification approaches.

    PubMed

    d'Ayala, Giovanna Gomez; Malinconico, Mario; Laurienzo, Paola

    2008-01-01

    Polysaccharide-based biomaterials are an emerging class in several biomedical fields such as tissue regeneration, particularly for cartilage, drug delivery devices and gelentrapment systems for the immobilization of cells. Important properties of the polysaccharides include controllable biological activity, biodegradability, and their ability to form hydrogels. Most of the polysaccharides used derive from natural sources; particularly, alginate and chitin, two polysaccharides which have an extensive history of use in medicine, pharmacy and basic sciences, and can be easily extracted from marine plants (algae kelp) and crab shells, respectively. The recent rediscovery of poly-saccharidebased materials is also attributable to new synthetic routes for their chemical modification, with the aim of promoting new biological activities and/or to modify the final properties of the biomaterials for specific purposes. These synthetic strategies also involve the combination of polysaccharides with other polymers. A review of the more recent research in the field of chemical modification of alginate, chitin and its derivative chitosan is presented. Moreover, we report as case studies the results of our recent work concerning various different approaches and applications of polysaccharide-based biomaterials, such as the realization of novel composites based on calcium sulphate blended with alginate and with a chemically modified chitosan, the synthesis of novel alginate-poly(ethylene glycol) copolymers and the development of a family of materials based on alginate and acrylic polymers of potential interest as drug delivery systems. PMID:18830142

  20. Biguanides inhibit complex I, II and IV of rat liver mitochondria and modify their functional properties.

    PubMed

    Drahota, Z; Palenickova, E; Endlicher, R; Milerova, M; Brejchova, J; Vosahlikova, M; Svoboda, P; Kazdova, L; Kalous, M; Cervinkova, Z; Cahova, M

    2014-01-01

    In this study, we focused on an analysis of biguanides effects on mitochondrial enzyme activities, mitochondrial membrane potential and membrane permeability transition pore function. We used phenformin, which is more efficient than metformin, and evaluated its effect on rat liver mitochondria and isolated hepatocytes. In contrast to previously published data, we found that phenformin, after a 5 min pre-incubation, dose-dependently inhibits not only mitochondrial complex I but also complex II and IV activity in isolated mitochondria. The enzymes complexes inhibition is paralleled by the decreased respiratory control index and mitochondrial membrane potential. Direct measurements of mitochondrial swelling revealed that phenformin increases the resistance of the permeability transition pore to Ca(2+) ions. Our data might be in agreement with the hypothesis of Schäfer (1976) that binding of biguanides to membrane phospholipids alters membrane properties in a non-specific manner and, subsequently, different enzyme activities are modified via lipid phase. However, our measurements of anisotropy of fluorescence of hydrophobic membrane probe diphenylhexatriene have not shown a measurable effect of membrane fluidity with the 1 mM concentration of phenformin that strongly inhibited complex I activity. Our data therefore suggest that biguanides could be considered as agents with high efficacy but low specifity. PMID:24182344

  1. Effects of biguanides on the intermediate metabolism of glucose in normal and portal-strictured rats.

    PubMed

    Schlienger, J L; Frick, A; Marbach, J; Freund, H; Imler, M

    1979-03-01

    Phenformin and metformin treatments may be complicated by lactic adidosis. This metabolic complication seems favoured by preexistent hepatic disease. We have therefore compared the metabolic effects of phenformin and metformin on non fasting normal and portal-strictured rats. The latter group is characterized by impaired hepatic passage of these drugs without hepatocellular lesions. Given orally to normal rats over 5 days, phenformin (20 mg/kg/24 h) and metformin (150 mg/kg/24 h) decreased blood glucose levels and increased blood urea and the substrates of gluconeogenesis (alanine, glutamine, lactic and pyruvic acids), effects more apparent with phenformin than metformin. In non-treated portal strictured rats, blood glucose levels were lower and the intermediate metabolites were higher than in noraml rats, suggesting a modification of gluconeogenesis. Treatment of the portal strictured group by phenformin or metformin induced no changes in the studied parameters. This absence of effect of the biguanides in portal strictured rats supports the postulate that, in normal rats, biguanides act principally on hepatic metabolism by reducing gluconeogenesis and that, in the absence of other hepatic damage, the presence of a peri-hepatic shunt, which, by itself, modifies gluconeogenesis, does not further predispose to lactic acidosis during short term administration of biguanides. PMID:446834

  2. Physical and chemical characterization of waste wood derived biochars.

    PubMed

    Yargicoglu, Erin N; Sadasivam, Bala Yamini; Reddy, Krishna R; Spokas, Kurt

    2015-02-01

    Biochar, a solid byproduct generated during waste biomass pyrolysis or gasification in the absence (or near-absence) of oxygen, has recently garnered interest for both agricultural and environmental management purposes owing to its unique physicochemical properties. Favorable properties of biochar include its high surface area and porosity, and ability to adsorb a variety of compounds, including nutrients, organic contaminants, and some gases. Physical and chemical properties of biochars are dictated by the feedstock and production processes (pyrolysis or gasification temperature, conversion technology and pre- and post-treatment processes, if any), which vary widely across commercially produced biochars. In this study, several commercially available biochars derived from waste wood are characterized for physical and chemical properties that can signify their relevant environmental applications. Parameters characterized include: physical properties (particle size distribution, specific gravity, density, porosity, surface area), hydraulic properties (hydraulic conductivity and water holding capacity), and chemical and electrochemical properties (organic matter and organic carbon contents, pH, oxidation-reduction potential and electrical conductivity, zeta potential, carbon, nitrogen and hydrogen (CHN) elemental composition, polycyclic aromatic hydrocarbons (PAHs), heavy metals, and leachable PAHs and heavy metals). A wide range of fixed carbon (0-47.8%), volatile matter (28-74.1%), and ash contents (1.5-65.7%) were observed among tested biochars. A high variability in surface area (0.1-155.1g/m(2)) and PAH and heavy metal contents of the solid phase among commercially available biochars was also observed (0.7-83 mg kg(-1)), underscoring the importance of pre-screening biochars prior to application. Production conditions appear to dictate PAH content--with the highest PAHs observed in biochar produced via fast pyrolysis and lowest among the gasification-produced biochars. PMID:25464942

  3. The biguanides metformin and phenformin inhibit angiogenesis, local and metastatic growth of breast cancer by targeting both neoplastic and microenvironment cells.

    PubMed

    Orecchioni, Stefania; Reggiani, Francesca; Talarico, Giovanna; Mancuso, Patrizia; Calleri, Angelica; Gregato, Giuliana; Labanca, Valentina; Noonan, Douglas M; Dallaglio, Katiuscia; Albini, Adriana; Bertolini, Francesco

    2015-03-15

    The human white adipose tissue (WAT) contains progenitors with cooperative roles in breast cancer (BC) angiogenesis, local and metastatic progression. The biguanide Metformin (Met), commonly used for Type 2 diabetes, might have activity against BC and was found to inhibit angiogenesis in vivo. We studied Met and another biguanide, phenformin (Phe), in vitro and in vivo in BC models. In vitro, biguanides activated AMPK, inhibited Complex 1 of the respiratory chain and induced apoptosis of BC and WAT endothelial cells. In coculture, biguanides inhibited the production of several angiogenic proteins. In vivo, biguanides inhibited local and metastatic growth of triple negative and HER2+ BC in immune-competent and immune-deficient mice orthotopically injected with BC. Biguanides inhibited local and metastatic BC growth in a genetically engineered murine model model of HER2+ BC. In vivo, biguanides increased pimonidazole binding (but not HIF-1 expression) of WAT progenitors, reduced tumor microvessel density and altered the vascular pericyte/endothelial cell ratio, so that cancer vessels displayed a dysplastic phenotype. Phe was significantly more active than Met both in vitro and in vivo. Considering their safety profile, biguanides deserve to be further investigated for BC prevention in high-risk subjects, in combination with chemo and/or targeted therapy and/or as post-therapy consolidation or maintenance therapy for the prevention of BC recurrence. PMID:25196138

  4. New polymeric biocides: synthesis and antibacterial activities of polycations with pendant biguanide groups.

    PubMed Central

    Ikeda, T; Yamaguchi, H; Tazuke, S

    1984-01-01

    Acrylate monomers with pendant biguanide groups were successfully synthesized, and their homopolymers and copolymers were prepared with acrylamide. These cationic disinfectants of polymeric forms exhibited high antibacterial activity against gram-positive bacteria, whereas they were less active against gram-negative bacteria. It was found that the activity of the polymeric disinfectants was much higher than that of the monomeric species, and the difference in activity between the polymers and the monomers was discussed on the basis of their contributions to each elementary process of the lethal action. PMID:6385836

  5. Iodine derivatives of chemically modified gum Arabic microspheres.

    PubMed

    Ganie, Showkat A; Ali, Akbar; Mazumdar, Nasreen

    2015-09-20

    Acetylated gum Arabic (AGA) derivatives with different degrees of substitution (DS 0.97-2.74) were synthesized using acetyl chloride and a base under varying reaction conditions. The AGA derivatives were obtained in the form of microspheres and thereafter stable iodine products were prepared by doping the microspheres with an iodinating agent, iodine monochloride (ICl). The reaction between electrophilic iodine and polar carbonyl groups was studied by FT-IR, (1)H-NMR, and UV-VIS spectroscopies. The products were also characterized by DSC, TGA and SEM studies. The incorporated iodine was released in aqueous medium as iodide ions (I(-)). A reaction scheme has been proposed for the iodination and de-iodination of the gum derivatives. This work suggests that the iodine derivatives of modified gum Arabic could be used as a source of iodide ions which is the nutritional form of iodine. PMID:26050909

  6. Reduced cytotoxicity of polyhexamethylene biguanide hydrochloride (PHMB) by egg phosphatidylcholine while maintaining antimicrobial efficacy.

    PubMed

    Müller, Gerald; Kramer, Axel; Schmitt, Jürgen; Harden, Daniela; Koburger, Torsten

    2011-04-25

    Liposomes or oil-in-water emulsions containing egg yolk phosphatidylcholine (EPC) were combined with aqueous polyhexamethylene biguanide hydrochloride (PHMB). The bactericidal activity of these preparations against Pseudomonas aeruginosa and Staphylococcus aureus as well as their cytotoxicity on cultured murine fibroblasts (L929 cells) was then assayed for either 30 min or 60 min in the presence of cell culture medium containing 10% fetal bovine serum as surrogate for wound fluid. We used two assay designs: in the first bactericidal activity and cytotoxicity were determined in separate experiments; in the second both were determined in one experiment. Combining PHMB and EPC containing o/w emulsions or liposomes protects mammalian cells without neutralizing the antiseptic effect. From all tested combinations the o/w emulsions containing 0.05% PHMB proved to be superior in this respect to the aqueous preparation. PMID:21356204

  7. Microbial production of fatty acid-derived fuels and chemicals

    PubMed Central

    Lennen, Rebecca M; Pfleger, Brian F

    2013-01-01

    Fatty acid metabolism is an attractive route to produce liquid transportation fuels and commodity oleochemicals from renewable feedstocks. Recently, genes and enzymes, which comprise metabolic pathways for producing fatty acid-derived compounds (e.g. esters, alkanes, olefins, ketones, alcohols, polyesters) have been elucidated and used in engineered microbial hosts. The resulting strains often generate products at low percentages of maximum theoretical yields, leaving significant room for metabolic engineering. Economically viable processes will require strains to approach theoretical yields, particularly for replacement of petroleum-derived fuels. This review will describe recent progress toward this goal, highlighting the scientific discoveries of each pathway, ongoing biochemical studies to understand each enzyme, and metabolic engineering strategies that are being used to improve strain performance. PMID:23541503

  8. Toxicological Actions of Plant-Derived and Anthropogenic Methylenedioxyphenyl-Substituted Chemicals in Mammals and Insects

    Microsoft Academic Search

    Michael Murray

    2012-01-01

    The methylenedioxyphenyl (MDP) substituent is a structural feature present in many plant chemicals that deter foraging by predatory insects and herbivores. With increasing use of herbal extracts in alternative medicine, human exposure to MDP-derived plant chemicals may also be significant. Early studies found that most MDP agents themselves possess relatively low intrinsic toxicity, but strongly influence the actions of other

  9. Chemical equilibrium. [maximizing entropy of gas system to derive relations between thermodynamic variables

    NASA Technical Reports Server (NTRS)

    1976-01-01

    The entropy of a gas system with the number of particles subject to external control is maximized to derive relations between the thermodynamic variables that obtain at equilibrium. These relations are described in terms of the chemical potential, defined as equivalent partial derivatives of entropy, energy, enthalpy, free energy, or free enthalpy. At equilibrium, the change in total chemical potential must vanish. This fact is used to derive the equilibrium constants for chemical reactions in terms of the partition functions of the species involved in the reaction. Thus the equilibrium constants can be determined accurately, just as other thermodynamic properties, from a knowledge of the energy levels and degeneracies for the gas species involved. These equilibrium constants permit one to calculate the equilibrium concentrations or partial pressures of chemically reacting species that occur in gas mixtures at any given condition of pressure and temperature or volume and temperature.

  10. Conical intersection seams in polyenes derived from their chemical composition

    SciTech Connect

    Nenov, Artur; Vivie-Riedle, Regina de [Department Chemie, Ludwig-Maximilians-Univerisitaet, Muenchen Butenandtstr. 11, 81377 Muenchen (Germany)

    2012-08-21

    The knowledge of conical intersection seams is important to predict and explain the outcome of ultrafast reactions in photochemistry and photobiology. They define the energetic low-lying reachable regions that allow for the ultrafast non-radiative transitions. In complex molecules it is not straightforward to locate them. We present a systematic approach to predict conical intersection seams in multifunctionalized polyenes and their sensitivity to substituent effects. Included are seams that facilitate the photoreaction of interest as well as seams that open competing loss channels. The method is based on the extended two-electron two-orbital method [A. Nenov and R. de Vivie-Riedle, J. Chem. Phys. 135, 034304 (2011)]. It allows to extract the low-lying regions for non-radiative transitions, which are then divided into small linear segments. Rules of thumb are introduced to find the support points for these segments, which are then used in a linear interpolation scheme for a first estimation of the intersection seams. Quantum chemical optimization of the linear interpolated structures yields the final energetic position. We demonstrate our method for the example of the electrocyclic isomerization of trifluoromethyl-pyrrolylfulgide.

  11. Sol-gel-derived micron scale optical fibers for chemical sensing

    Microsoft Academic Search

    U. Narang; R. Gvishi; F. V. Bright; P. N. Prasad

    1996-01-01

    We report for the first time on the preparation of organically-doped room temperature processed sol-gel-derived micron scale optical fibers as platforms for chemical- and bio-sensors. Micron scale optical fibers are drawn from fluorescent dye-doped tetraethoxysilane (TEOS)-derived sol-gel solution processed under ambient conditions. Such a simple methodology to entrap organic and even bioactive species within the optical fiber offers many advantages

  12. Assessment of the mode of action of polyhexamethylene biguanide against Listeria innocua by Fourier transformed infrared spectroscopy and fluorescence anisotropy analysis.

    PubMed

    Chadeau, Elise; Dumas, Emilie; Adt, Isabelle; Degraeve, Pascal; Noël, Claude; Girodet, Christophe; Oulahal, Nadia

    2012-12-01

    Polyhexamethylene biguanide (PHMB) is a cationic biocide. The antibacterial mode of action of PHMB (at concentrations not exceeding its minimal inhibitory concentration) upon Listeria innocua LRGIA 01 was investigated by Fourier transformed infrared spectroscopy and fluorescence anisotropy analysis. Fourier transformed infrared spectra of bacteria treated with or without PHMB presented some differences in the lipids region: the CH(2)/CH(3) (2924 cm(-1)/2960 cm(-1)) band areas ratio significantly increased in the presence of PHMB. Since this ratio generally reflects membrane phospholipids and membrane microenvironment of the cells, these results suggest that PHMB molecules interact with membrane phospholipids and, thus, affect membrane fluidity and conformation. To assess the hypothesis of PHMB interaction with L. innocua membrane phospholipids and to clarify the PHMB mode of action, we performed fluorescence anisotropy experiments. Two probes, 1,6-diphenyl-1,3,5-hexatriene (DPH) and its derivative 1-[4-(trimethyl-amino)-phenyl]-6-phenylhexa-1,3,5-triene (TMA-DPH), were used. DPH and TMA-DPH incorporate inside and at the surface of the cytoplasmic membrane, respectively. When PHMB was added, an increase of TMA-DPH fluorescence anisotropy was observed, but no changes of DPH fluorescence anisotropy occurred. These results are consistent with the hypothesis that PHMB molecules perturb L. innocua LRGIA 01 cytoplasmic membrane by interacting with the first layer of the membrane lipid bilayer. PMID:23210992

  13. Understanding the biocide action of poly(hexamethylene biguanide) using Langmuir monolayers of dipalmitoyl phosphatidylglycerol.

    PubMed

    Souza, Adriano L; Ceridório, Lucinéia F; Paula, Gustavo F; Mattoso, Luiz H C; Oliveira, Osvaldo N

    2015-08-01

    The disinfectant activity of poly(hexamethylene biguanide) (PHMB) has been explored in industrial applications, in agriculture and in food manipulation, but this biocide action is not completely understood. It is believed to arise from electrostatic interactions between the polyhexanide group and phosphatidylglycerol, which is the main phospholipid on the bacterial membrane. In this study, we investigated the molecular-level interactions between PHMB and dipalmitoyl phosphatidylglycerol (DPPG) in Langmuir monolayers that served as cell membrane models. PHMB at a concentration of 2×10(-4)gL(-1) in a Theorell-Stenhagen at pH 3.0 and in a phosphate at pH 7.4 was used as a subphase to prepare the DPPG monolayers. Surface pressure-area isotherms showed that PHMB adsorbs and penetrates into the DPPG monolayers, expanding them and increasing their elasticity under both conditions examined. Results from polarization-modulated infrared reflection absorption spectroscopy (PM-IRRAS) indicated that PHMB induces disorder in the DPPG chains and dehydrates their CO groups, especially for the physiological medium. Overall, these findings point to hydrophobic interactions and dehydration being as relevant as electrostatic interactions to explain changes in membrane fluidity and permeability, believed to be responsible for the biocide action of PHMB. PMID:26037700

  14. Antimicrobial electrospun membranes of chitosan/poly(ethylene oxide) incorporating poly(hexamethylene biguanide) hydrochloride.

    PubMed

    Dilamian, M; Montazer, M; Masoumi, J

    2013-04-15

    Here, antimicrobial nanofibrous membranes were produced by electrospinning of chitosan/poly(ethylene oxide) (PEO) solution in the presence of poly(hexamethylene biguanide) hydrochloride (PHMB). The influence of PHMB on the electrospinnability and antimicrobial properties of chitosan/PEO nanofibers were studied. Further, viscosity of the solutions as well as morphology of the nanofibrous structures were investigated. Results revealed that incorporation of PHMB in chitosan/PEO solutions led to decrease in the zero-shear rate viscosity up to 20%. Moreover, increasing PHMB from 0.5 mM to 1 mM led to formation of thinner fibers with diameters ranging from 240 nm to 60 nm, respectively. Fourier transform infrared (FT-IR) spectrums indicated the functional groups of chitosan, PEO and PHMB in nanofibrous structure. Differential scanning calorimetry (DSC) thermograms indicated interaction of PHMB with PEO and chitosan through alteration in the thermal behavior of the nanofibers. Inhibition of the bacteria growth for both Escherichia coli and Staphylococcus aureus were achieved on the PHMB loaded nanofibers. Also, a burst release of PHMB from mats has been observed in the first hour. These findings suggest that there is a great potential in fabrication of biomaterials with incorporation of PHMB using electrospinning. PMID:23544550

  15. Determination of polyhexamethylene biguanide hydrochloride using photometric colloidal titration with crystal violet as a color indicator.

    PubMed

    Masadome, Takashi; Miyanishi, Takaaki; Watanabe, Keita; Ueda, Hiroshi; Hattori, Toshiaki

    2011-01-01

    A solution of polyhexamethylene biguanide hydrochloride (PHMB-HCl) was titrated with a standard solution of potassium poly(vinyl sulfate) (PVSK) using crystal violet (CV) as an photometric indicator cation. The end point was detected by a sharp absorbance change due to an abrupt decrease in the concentration of CV. A linear relationship between the concentration of PHMB-HCl and the end-point volume of the titrant existed in the concentration range from 2 to 10 × 10(-6) eq mol L(-1). Back-titration was based on adding an excess amount of PVSK to a sample solution containing CV, which was titrated with a standard solution of poly(diallyldimethylammonium chloride) (PDADMAC). The calibration curve of the PHMB-HCl concentration to the end point volume of the titrant was also linear in the concentration range from 2 to 8 × 10(-6) eq mol L(-1). Both photometric titrations were applied to the determination of PHMB-HCl in a few contact-lens detergents. Back-titration showed a clear end point, but direct titration showed an unclear end point. The results of the back-titration of PHMB-HCl were compared with the content registered in its labels. PMID:21828919

  16. Bactericidal core-shell paramagnetic nanoparticles functionalized with poly(hexamethylene biguanide).

    PubMed

    Bromberg, Lev; Chang, Emily P; Hatton, T Alan; Concheiro, Angel; Magariños, Beatriz; Alvarez-Lorenzo, Carmen

    2011-01-01

    Bactericidal paramagnetic particles were obtained either through the attachment of a conjugate of poly(ethyleneimine) (PEI) and poly(hexamethylene biguanide) (PHMBG) to the surface of magnetite (Fe(3)O(4)) particles, or via the sol-gel encapsulation of magnetite particles with a functional silane (3-glycidoxypropyl trimethoxysilane) and subsequent binding of the polysiloxane shell by the amine/imine groups of PHMBG. The encapsulated core-shell particles possess a high saturation magnetization, which is preserved for more than 10 months while in contact with air in aqueous suspensions. The minimum inhibitory concentration (MIC) of the encapsulated particles for eight types of bacteria was size-dependent, with polydisperse submillimeter particles possessing a several-fold higher MIC than analogous particles sized below 250 nm. The encapsulated particles are biocompatible and nontoxic to mammalian cells such as mouse fibroblasts. The particles efficiently bind both glycopeptide components mimicking the gram-positive bacteria membranes and whole bacteria, and possess broad-range bactericidal activity. The cell-particle complexes can be captured, manipulated, and removed by means of a magnet. PMID:21138282

  17. Chemical Vapor Deposition-Derived Graphene with Electrical Performance of Exfoliated Graphene

    E-print Network

    Hone, James

    Chemical Vapor Deposition-Derived Graphene with Electrical Performance of Exfoliated Graphene a scalable method to produce large-area graphene, CVD-grown graphene has heretofore exhibited inferior of CVD-grown graphene in which two important sources of disorder, namely grain boundaries and processing

  18. The construction of tandem dye-sensitized solar cells from chemically-derived nanoporous photoelectrodes

    E-print Network

    Park, Byungwoo

    The construction of tandem dye-sensitized solar cells from chemically-derived nanoporous Available online 24 October 2014 Keywords: Tandem solar cell Selective etching Dye-sensitized solar cell Nanoporous electrode a b s t r a c t A tandem dye-sensitized solar cell (tandem-DSSC) was synthesized

  19. Correlation between chemical structure and rodent repellency of benzoic acid derivatives

    USGS Publications Warehouse

    Fearn, J.E.; DeWitt, J.B.

    1965-01-01

    Sixty-five benzoic acid derivatives were either prepared or obtained from commercial concerns, tested for rat repellency, and their indices of repellency computed. The data from these tests were considered analytically for any correlation between chemical structure and rat repellency. The results suggest a qualitative relationship which is useful in deciding probability of repellency in other compounds.

  20. Production of Fatty Acid-Derived Valuable Chemicals in Synthetic Microbes

    PubMed Central

    Yu, Ai-Qun; Pratomo Juwono, Nina Kurniasih; Leong, Susanna Su Jan; Chang, Matthew Wook

    2014-01-01

    Fatty acid derivatives, such as hydroxy fatty acids, fatty alcohols, fatty acid methyl/ethyl esters, and fatty alka(e)nes, have a wide range of industrial applications including plastics, lubricants, and fuels. Currently, these chemicals are obtained mainly through chemical synthesis, which is complex and costly, and their availability from natural biological sources is extremely limited. Metabolic engineering of microorganisms has provided a platform for effective production of these valuable biochemicals. Notably, synthetic biology-based metabolic engineering strategies have been extensively applied to refactor microorganisms for improved biochemical production. Here, we reviewed: (i) the current status of metabolic engineering of microbes that produce fatty acid-derived valuable chemicals, and (ii) the recent progress of synthetic biology approaches that assist metabolic engineering, such as mRNA secondary structure engineering, sensor-regulator system, regulatable expression system, ultrasensitive input/output control system, and computer science-based design of complex gene circuits. Furthermore, key challenges and strategies were discussed. Finally, we concluded that synthetic biology provides useful metabolic engineering strategies for economically viable production of fatty acid-derived valuable chemicals in engineered microbes. PMID:25566540

  1. Production of Fatty Acid-derived valuable chemicals in synthetic microbes.

    PubMed

    Yu, Ai-Qun; Pratomo Juwono, Nina Kurniasih; Leong, Susanna Su Jan; Chang, Matthew Wook

    2014-01-01

    Fatty acid derivatives, such as hydroxy fatty acids, fatty alcohols, fatty acid methyl/ethyl esters, and fatty alka(e)nes, have a wide range of industrial applications including plastics, lubricants, and fuels. Currently, these chemicals are obtained mainly through chemical synthesis, which is complex and costly, and their availability from natural biological sources is extremely limited. Metabolic engineering of microorganisms has provided a platform for effective production of these valuable biochemicals. Notably, synthetic biology-based metabolic engineering strategies have been extensively applied to refactor microorganisms for improved biochemical production. Here, we reviewed: (i) the current status of metabolic engineering of microbes that produce fatty acid-derived valuable chemicals, and (ii) the recent progress of synthetic biology approaches that assist metabolic engineering, such as mRNA secondary structure engineering, sensor-regulator system, regulatable expression system, ultrasensitive input/output control system, and computer science-based design of complex gene circuits. Furthermore, key challenges and strategies were discussed. Finally, we concluded that synthetic biology provides useful metabolic engineering strategies for economically viable production of fatty acid-derived valuable chemicals in engineered microbes. PMID:25566540

  2. Chemical Derivatives and Elemental Transport Coefficients in Plasma Flows Near Local Equilibrium

    SciTech Connect

    Orsini, Alessio [Avio Aerospace Propulsion, via I Maggio 99, 10040 Rivalta di Torino (Italy); Kustova, Elena V. [Saint Petersburg State University, Department of Mathematics and Mechanics, 198504, Universitetsky pr. 28, Saint Petersburg (Russian Federation)

    2011-05-20

    Elemental transport coefficients are extensively used for modeling chemically reacting and plasma flows when the proximity to local equilibrium is exploited to combine the ordinary transport coefficients into a few elemental coefficients. A deeper insight into the physics of chemically reacting flows near local equilibrium can be achieved by looking only at a reduced number of relevant parameters in the expression of the flow transport properties.A new technique to calculate chemical derivatives using an analytical method which strongly reduces computational effort and numerical errors is introduced. A general formalism for elemental diffusion velocities, heat flux and electric current for plasma flows near local equilibrium is then derived. An order of magnitude analysis shows how to identify the main contributions to the transport fluxes among: elemental fractions gradients, pressure or temperature gradients, electric field. The resulting theoretical framework is particularly suitable for numerical implementation.The present contribution aims to provide a summary of the theoretical framework described above. Numerical examples of chemical derivatives and elemental transport coefficients are given. Results are presented for a carbon dioxide mixture of practical interest for aerospace applications and atmospheric entry problems.

  3. Effects of Hemoglobin Variants and Chemically Modified Derivatives on Assays for Glycohemoglobin

    Microsoft Academic Search

    Lynn Bry; Philip C. Chen; David B. Sacks

    2001-01-01

    Background: Glycohemoglobin (gHb), measured as he- moglobin (Hb) A1c or as total gHb, provides a common means for assessing long-term glycemic control in indi- viduals with diabetes mellitus. Genetic variants and chemically modified derivatives of Hb can profoundly affect the accuracy of these measurements, although effects vary considerably among commercially available methods. The prevalence of genetic variants such as HbS,

  4. Xenobiotic responsiveness of Arabidopsis thaliana to a chemical series derived from a herbicide safener.

    PubMed

    Skipsey, Mark; Knight, Kathryn M; Brazier-Hicks, Melissa; Dixon, David P; Steel, Patrick G; Edwards, Robert

    2011-09-16

    Plants respond to synthetic chemicals by eliciting a xenobiotic response (XR) that enhances the expression of detoxifying enzymes such as glutathione transferases (GSTs). In agrochemistry, the ability of safeners to induce an XR is used to increase herbicide detoxification in cereal crops. Based on the responsiveness of the model plant Arabidopsis thaliana to the rice safener fenclorim (4,6-dichloro-2-phenylpyrimidine), a series of related derivatives was prepared and tested for the ability to induce GSTs in cell suspension cultures. The XR in Arabidopsis could be divided into rapid and slow types depending on subtle variations in the reactivity (electrophilicity) and chemical structure of the derivatives. In a comparative microarray study, Arabidopsis cultures were treated with closely related compounds that elicited rapid (fenclorim) and slow (4-chloro-6-methyl-2-phenylpyrimidine) XRs. Both chemicals induced major changes in gene expression, including a coordinated suppression in cell wall biosynthesis and an up-regulation in detoxification pathways, whereas only fenclorim selectively induced sulfur and phenolic metabolism. These transcriptome studies suggested several linkages between the XR and oxidative and oxylipin signaling. Confirming links with abiotic stress signaling, suppression of glutathione content enhanced GST induction by fenclorim, whereas fatty acid desaturase mutants, which were unable to synthesize oxylipins, showed an attenuated XR. Examining the significance of these studies to agrochemistry, only those fenclorim derivatives that elicited a rapid XR proved effective in increasing herbicide tolerance (safening) in rice. PMID:21778235

  5. Microstructural aspects of nanocrystalline LiZn ferrites densified with chemically derived additives

    SciTech Connect

    Cho, Y.S.; Burdick, V.L.; Amarakoon, V.R.W. [Alfred Univ., NY (United States). New York State Coll. of Ceramics; Underhill, E.; Brissette, L. [Electromagnetic Science Technologies Inc., Norcross, GA (United States)

    1998-12-31

    Densification behavior and microstructural characteristics of nanocrystalline LiZn ferrites with chemically derived additives were investigated. Nanocrystalline Li{sub 0.3}Zn{sub 0.4}Fe{sub 2.3}O{sub 4} powders having a {approx} 15 nm size were prepared at a low temperature of 450 C by a chemical synthesis using a combustible polyacrylic acid (PAA). Small amounts of Si, Ca and Mn were incorporated into the nanocrystalline ferrites via sol-gel reactions utilizing tetraethyl orthosilicate, calcium isopropoxide and manganese acetate. This process was believed to give a homogeneous distribution of the additives over the nanocrystalline ferrites. A uniform microstructure was obtained without any evidence of exaggerated grain growth after sintering at 1,100 C. Saturation magnetization and coercive force were found to increase with the chemical additives. The results were compared with those of the same composition, but processed by the conventional batch-mixing of corresponding oxide additives.

  6. Inhibition of anthrax lethal factor by curcumin and chemically modified curcumin derivatives

    PubMed Central

    Zhang, Yu; Golub, Lorne M.; Johnson, Francis; Simon, Sanford R.

    2014-01-01

    Curcuma longa Curcumin (diferuloylmethane), the active ingredient in the eastern spice turmeric (Curcuma longa), has been shown to inhibit the activities of numerous enzymes and signaling molecules involved in cancer, bacterial and viral infections and inflammatory diseases. We have investigated the inhibitory activities of curcumin and chemically modified curcumin (CMC) derivatives toward lethal factor (LF), the proteolytic component of anthrax toxin produced by the bacterium Bacillus anthracis. Curcumin (Compound 1) appears to inhibit the catalytic activity of LF through a mixture of inhibitory mechanisms, without significant compromise to the binding of oligopeptide substrates, and one CMC derivative in particular, Compound 3 (4-phenylaminocarbonylbis-demethoxycurcumin), is capable of inhibiting LF with potency comparable with the parent compound, while also showing improved solubility and stability. The quantitative reduction in catalytic activity achieved by the different CMC derivatives appears to be a function of the proportion of the multiple mechanisms through which they inhibit the enzyme. PMID:24102525

  7. Inhibition of anthrax lethal factor by curcumin and chemically modified curcumin derivatives.

    PubMed

    Antonelli, Anthony C; Zhang, Yu; Golub, Lorne M; Johnson, Francis; Simon, Sanford R

    2014-10-01

    Curcumin (diferuloylmethane), the active ingredient in the eastern spice turmeric (Curcuma longa), has been shown to inhibit the activities of numerous enzymes and signaling molecules involved in cancer, bacterial and viral infections and inflammatory diseases. We have investigated the inhibitory activities of curcumin and chemically modified curcumin (CMC) derivatives toward lethal factor (LF), the proteolytic component of anthrax toxin produced by the bacterium Bacillus anthracis. Curcumin (Compound 1) appears to inhibit the catalytic activity of LF through a mixture of inhibitory mechanisms, without significant compromise to the binding of oligopeptide substrates, and one CMC derivative in particular, Compound 3 (4-phenylaminocarbonylbis-demethoxycurcumin), is capable of inhibiting LF with potency comparable with the parent compound, while also showing improved solubility and stability. The quantitative reduction in catalytic activity achieved by the different CMC derivatives appears to be a function of the proportion of the multiple mechanisms through which they inhibit the enzyme. PMID:24102525

  8. Inorganic salts of biguanide Searching for new materials for second harmonic generation

    NASA Astrophysics Data System (ADS)

    Matulková, Irena; N?mec, Ivan; Císa?ová, Ivana; N?mec, Petr; Mi?ka, Zden?k

    2008-08-01

    Five inorganic salts of biguanide with carbonic, nitric, phosphoric and phosphorous acids were prepared and X-ray structural analysis has been performed for three novel compounds. Biguanidium(1+) phosphite trihydrate crystallizes in the triclinic space group P1¯, a = 7.1470(1) Å, b = 9.6530(2) Å, c = 11.3140(2) Å, ? = 70.094(1)°, ? = 75.688(1)°, ? = 86.099(1)°, V = 713.71(2) Å 3, Z = 2, R = 0.0350 for 3031 observed reflections. The crystal structure is based on a network of phosphite anions and water molecules. Biguanidium(1+) cations form pairs through two intermolecular hydrogen bonds of the N-H…N type and fill the network with anions and water molecules. Biguanidium(2+) phosphite monohydrate crystallizes in the triclinic space group P1¯, a = 6.9690(2) Å, b = 7.3500(3) Å, c = 8.1730(3) Å, ? = 82.518(2)°, ? = 83.015(2)°, ? = 82.811(2)°, V = 409.44(3) Å 3, Z = 2, R = 0.0308 for 1779 observed reflections. The structure is formed of a network of alternating biguanidium(2+) cations, phosphite anions and pairs of water molecules interconnected by a system of intermolecular hydrogen bonds. Biguanidium(2+) hydrogen phosphate monohydrate crystallizes in the triclinic space group P1¯, a = 7.0630(2) Å, b = 7.8740(3) Å, c = 8.1120(3) Å, ? = 102.706(2)°, ? = 104.976(2)°, ? = 92.632(3)°, V = 422.61(3) Å 3, Z = 2, R = 0.0337 for 1827 observed reflections. The crystal structure is formed by pairs of anions that are mutually connected in chains through two water molecules. These chains are interconnected by biguanidium(2+) cations to form a three-dimensional network. The FTIR and FT Raman spectra of all five compounds were recorded, calculated (HF, B3LYP and MP2 methods) and discussed. Quantitative measurements of second harmonic generation of powdered biguanidium(2+) nitrate and novel biguanidium(2+) carbonate monohydrate at 800 nm were performed and a relative efficiency (compared to KDP) of 87% and 20% was observed, respectively.

  9. Surface chemical functionalities affect the behavior of human adipose-derived stem cells in vitro

    NASA Astrophysics Data System (ADS)

    Liu, Xujie; Feng, Qingling; Bachhuka, Akash; Vasilev, Krasimir

    2013-04-01

    This study examines the effect of surface chemical functionalities on the behavior of human adipose-derived stem cells (hASCs) in vitro. Plasma polymerized films rich in amine (sbnd NH2), carboxyl (sbnd COOH) and methyl (sbnd CH3), were generated on hydroxyapatite (HAp) substrates. The surface chemical functionalities were characterized by X-ray photoelectron spectroscopy (XPS). The ability of different substrates to absorb proteins was evaluated. The results showed that substrates modified with hydrophilic functional group (sbnd COOH and sbnd NH2) can absorb more proteins than these modified with more hydrophobic functional group (sbnd CH3). The behavior of human adipose-derived stem cells (hASCs) cultured on different substrates was investigated in vitro: cell counting kit-8 (CCK-8) analysis was used to characterize cell proliferation, scanning electronic microscopy (SEM) analysis was used to characterize cell morphology and alkaline phosphatase (ALP) activity analysis was used to account for differentiation. The results of this study demonstrated that the sbnd NH2 modified surfaces encourage osteogenic differentiation; the sbnd COOH modified surfaces promote cell adhesion and spreading and the sbnd CH3 modified surfaces have the lowest ability to induce osteogenic differentiation. These findings confirmed that the surface chemical states of biomaterials can affect the behavior of hASCs in vitro.

  10. Evaluation of Chemical Warfare Agent Percutaneous Vapor Toxicity: Derivation of Toxicity Guidelines for Assessing Chemical Protective Ensembles.

    SciTech Connect

    Watson, A.P.

    2003-07-24

    Percutaneous vapor toxicity guidelines are provided for assessment and selection of chemical protective ensembles (CPEs) to be used by civilian and military first responders operating in a chemical warfare agent vapor environment. The agents evaluated include the G-series and VX nerve agents, the vesicant sulfur mustard (agent HD) and, to a lesser extent, the vesicant Lewisite (agent L). The focus of this evaluation is percutaneous vapor permeation of CPEs and the resulting skin absorption, as inhalation and ocular exposures are assumed to be largely eliminated through use of SCBA and full-face protective masks. Selection of appropriately protective CPE designs and materials incorporates a variety of test parameters to ensure operability, practicality, and adequacy. One aspect of adequacy assessment should be based on systems tests, which focus on effective protection of the most vulnerable body regions (e.g., the groin area), as identified in this analysis. The toxicity range of agent-specific cumulative exposures (Cts) derived in this analysis can be used as decision guidelines for CPE acceptance, in conjunction with weighting consideration towards more susceptible body regions. This toxicity range is bounded by the percutaneous vapor estimated minimal effect (EME{sub pv}) Ct (as the lower end) and the 1% population threshold effect (ECt{sub 01}) estimate. Assumptions of exposure duration used in CPE certification should consider that each agent-specific percutaneous vapor cumulative exposure Ct for a given endpoint is a constant for exposure durations between 30 min and 2 hours.

  11. Hierarchy of Electronic Properties of Chemically Derived and Pristine Graphene Probed by Microwave Imaging

    SciTech Connect

    Kundhikanjana, W.

    2010-06-02

    Local electrical imaging using microwave impedance microscope is performed on graphene in different modalities, yielding a rich hierarchy of the local conductivity. The low-conductivity graphite oxide and its derivatives show significant electronic inhomogeneity. For the conductive chemical graphene, the residual defects lead to a systematic reduction of the microwave signals. In contrast, the signals on pristine graphene agree well with a lumped-element circuit model. The local impedance information can also be used to verify the electrical contact between overlapped graphene pieces.

  12. Derivation of the chemical-equilibrium rate coefficient using scattering theory

    NASA Technical Reports Server (NTRS)

    Mickens, R. E.

    1977-01-01

    Scattering theory is applied to derive the equilibrium rate coefficient for a general homogeneous chemical reaction involving ideal gases. The reaction rate is expressed in terms of the product of a number of normalized momentum distribution functions, the product of the number of molecules with a given internal energy state, and the spin-averaged T-matrix elements. An expression for momentum distribution at equilibrium for an arbitrary molecule is presented, and the number of molecules with a given internal-energy state is represented by an expression which includes the partition function.

  13. Chemical looping combustion of biomass-derived syngas using ceria-supported oxygen carriers.

    PubMed

    Huang, H B; Aisyah, L; Ashman, P J; Leung, Y C; Kwong, C W

    2013-07-01

    Cu, Ni and Fe oxides supported on ceria were investigated for their performance as oxygen carriers during the chemical looping combustion of biomass-derived syngas. A complex gas mixture containing CO, H2, CO2, CH4 and other hydrocarbons was used to simulate the complex fuel gas environment derived from biomass gasification. Results show that the transfer of the stored oxygen into oxidants for the supported Cu and Ni oxides at 800°C for the combustion of syngas was effective (>85%). The unsupported Cu oxide showed high oxygen carrying capacity but particle sintering was observed at 800°C. A reaction temperature of 950°C was required for the supported Fe oxides to transfer the stored oxygen into oxidants effectively. Also, for the complex fuel gas environment, the supported Ni oxide was somewhat effective in reforming CH4 and other light hydrocarbons into CO, which may have benefits for the reduction of tar produced during biomass pyrolysis. PMID:23711944

  14. Determination of the chemical structures of tandyukisins B-d, isolated from a marine sponge-derived fungus.

    PubMed

    Yamada, Takeshi; Umebayashi, Yoshihide; Kawashima, Maiko; Sugiura, Yuma; Kikuchi, Takashi; Tanaka, Reiko

    2015-01-01

    Tandyukisins B-D (1-3), novel decalin derivatives, have been isolated from a strain of Trichoderma harzianum OUPS-111D-4 originally derived from the marine sponge Halichondria okadai, and their structures have been elucidated on the basis of spectroscopic analyses using 1D and 2D NMR techniques. In addition, their chemical structures were established by chemical transformation. They exhibited weak cytotoxicity, but selective growth inhibition on panel screening using 39 human cancer cell lines. PMID:26006715

  15. Determination of the Chemical Structures of Tandyukisins B–D, Isolated from a Marine Sponge-Derived Fungus

    PubMed Central

    Yamada, Takeshi; Umebayashi, Yoshihide; Kawashima, Maiko; Sugiura, Yuma; Kikuchi, Takashi; Tanaka, Reiko

    2015-01-01

    Tandyukisins B–D (1–3), novel decalin derivatives, have been isolated from a strain of Trichoderma harzianum OUPS-111D-4 originally derived from the marine sponge Halichondria okadai, and their structures have been elucidated on the basis of spectroscopic analyses using 1D and 2D NMR techniques. In addition, their chemical structures were established by chemical transformation. They exhibited weak cytotoxicity, but selective growth inhibition on panel screening using 39 human cancer cell lines. PMID:26006715

  16. Interaction of polyhexamethylene biguanide hydrochloride (PHMB) with phosphatidylcholine containing o/w emulsion and consequences for microbicidal efficacy and cytotoxicity.

    PubMed

    Müller, Gerald; Koburger, Torsten; Kramer, Axel

    2013-01-25

    Oil-in-water (o/w) emulsions containing egg yolk phosphatidylcholine (EPC) were combined with aqueous polyhexamethylene biguanide hydrochloride (PHMB). The PHMB concentration in the aqueous phase was estimated by filtration centrifugation experiments. In parallel, PHMB concentration was assessed utilizing cytotoxicity assays (neutral red) on cultured murine fibroblasts (L929 cells) and tests of bactericidal efficacy on either Pseudomonas aeruginosa or Staphylococcus aureus. Biological tests were performed in cell culture medium. Filtration centrifugation experiments demonstrated much higher aqueous PHMB concentrations than did the assays for biologically effective PHMB. Therefore, biological test systems should preferably be used to verify effective PHMB concentrations. Tests of microbicidal efficacy in which the same 0.05% PHMB o/w emulsion was re-used 8 times revealed a drug delivery system activated by the presence of test bacteria. PMID:23313712

  17. Chemical constituents of marine mangrove-derived endophytic fungus Alternaria tenuissima EN-192

    NASA Astrophysics Data System (ADS)

    Sun, Hong; Gao, Shushan; Li, Xiaoming; Li, Chunshun; Wang, Bingui

    2013-03-01

    A chemical investigation of the ethyl acetate extract of the fermentation broth of Alternaria tenuissima EN-192, an endophytic fungus obtained from the stems of the marine mangrove plant Rhizophora stylosa, resulted in the isolation of nine known secondary metabolites, including four indole-diterpenoids: penijanthine A ( 1), paspaline ( 2), paspalinine ( 3), and penitrem A ( 4); three tricycloalternarene derivatives: tricycloalternarene 3a ( 5), tricycloalternarene 1b ( 6), and tricycloalternarene 2b ( 7); and two alternariol congeners: djalonensone ( 8) and alternariol ( 9). The chemical structures of these metabolites were characterized through a combination of detailed spectroscopic analyses and their comparison with reports from the literature. The inhibitory activities of each isolated compound against four bacteria were evaluated and compounds 5 and 8 displayed moderate activity against the aquaculture pathogenic bacterium Vibrio anguillarum, with inhibition zone diameters of 8 and 9 mm, respectively, at 100 ?g/disk. To the best of our knowledge, this is the first report on the secondary metabolites of mangrove-derived A lternaria tenuissima and also the first report of the isolation of indole-diterpenoids from fungal genus A lternaria.

  18. Chemical composition of acid–base fractions separated from biooil derived by fast pyrolysis of chicken manure

    Microsoft Academic Search

    Dharani D. Das; Morris I. Schnitzer; Carlos M. Monreal; Paul Mayer

    2009-01-01

    Our earlier investigations on the chemical composition of biooils derived by the fast pyrolysis of chicken manure revealed the presence of more than 500 compounds. In order to simplify this heterogeneous and complex chemical system, we produced four biooil fractions namely strongly acidic fraction A, weakly acidic fraction B, basic fraction C and neutral fraction D on the basis of

  19. Comparison of models to analyze mortality data and derive concentration-time response relationship of inhaled chemicals

    E-print Network

    Paris-Sud XI, Université de

    relationship of inhaled chemicals Alexandre R.R Pérya* , A. Troisea,b , S. Tissotb and J.M. Vincentb INERIS BP2.02.005 #12;2 Abstract The derivation of thresholds for lethal effects for inhaled chemicals is a key issue

  20. Comments on the processing of the niobium component for chemical solution derived niobium oxide-based thin-films

    Microsoft Academic Search

    Mark Röscher; Theodor Schneller; Rainer Waser

    2010-01-01

    The impact of chemical precursor modification on the electronic properties of chemical solution deposition derived niobium\\u000a oxide thin-films has been evaluated. It has been found that the application of certain chemical modifications is mandatory\\u000a in order to obtain electrically insulating thin-films at low processing temperatures. It is emphasized that the devised optimal\\u000a way of processing for the niobium component is

  1. Metabolic engineering of Saccharomyces cerevisiae for production of fatty acid-derived biofuels and chemicals.

    PubMed

    Runguphan, Weerawat; Keasling, Jay D

    2014-01-01

    As the serious effects of global climate change become apparent and access to fossil fuels becomes more limited, metabolic engineers and synthetic biologists are looking towards greener sources for transportation fuels. In recent years, microbial production of high-energy fuels by economically efficient bioprocesses has emerged as an attractive alternative to the traditional production of transportation fuels. Here, we engineered the budding yeast Saccharomyces cerevisiae to produce fatty acid-derived biofuels and chemicals from simple sugars. Specifically, we overexpressed all three fatty acid biosynthesis genes, namely acetyl-CoA carboxylase (ACC1), fatty acid synthase 1 (FAS1) and fatty acid synthase 2 (FAS2), in S. cerevisiae. When coupled to triacylglycerol (TAG) production, the engineered strain accumulated lipid to more than 17% of its dry cell weight, a four-fold improvement over the control strain. Understanding that TAG cannot be used directly as fuels, we also engineered S. cerevisiae to produce drop-in fuels and chemicals. Altering the terminal "converting enzyme" in the engineered strain led to the production of free fatty acids at a titer of approximately 400 mg/L, fatty alcohols at approximately 100mg/L and fatty acid ethyl esters (biodiesel) at approximately 5 mg/L directly from simple sugars. We envision that our approach will provide a scalable, controllable and economic route to this important class of chemicals. PMID:23899824

  2. Chemical Combination of Biologically Active Derivatives ofN-Acetylmuramoyl Dipeptide and Lipid-A, and Their Biological Activities

    Microsoft Academic Search

    Akira Hasegawa; Eiji Seki; Yushun Fujishima; Koji Kigawa; Makoto Kiso; Hideharu Ishida; Ichiro Azuma

    1986-01-01

    Chemical coupling of biologically active derivatives of N-acetyl-muramoyl dipeptide with a derivative related to the nonreducing sub-unit of lipid A was carried out using acyl groups as a spacer. The products exhibited efficient antitumor activity, as well as strong, immunoadjuvant activity.

  3. Chemical and molecular aspects on interactions of galanthamine and its derivatives with cholinesterases.

    PubMed

    Gulcan, Hayrettin O; Orhan, Ilkay E; Sener, Bilge

    2015-01-01

    Dual action of galanthamine as potent cholinesterase inhibitor and nicotinic modulator has attracted a great attention to be used in the treatment of AD. Consequently, galanthamine, a natural alkaloid isolated from a Galanthus species (snowdrop, Amaryllidaceae), has become an attractive model compound for synthesis of its novel derivatives to discover new drug candidates. Numerous studies have been done to elucidate interactions between galanthamine and its different derivatives and the enzymes; acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) using in vitro and in silico experimental models. The in vitro studies revealed that galanthamine inhibits AChE in strong, competitive, long-acting, and reversible manner as well as BChE, although its selectivity towards AChE is much higher than BChE. The in silico studies carried out by employing molecular docking experiments as well as molecular dynamics simulations pointed out to existence of strong interactions of galanthamine with the active gorge of AChE, mostly of Torpedo californica (the Pasific electric ray) origin. In this review, we evaluate the mainstays of cholinesterase inhibitory action of galanthamine and its various derivatives from the point of view of chemical and molecular aspects. PMID:25483718

  4. Monocyte cytokine secretion induced by chemically-defined derivatives of Klebsiella pneumoniae.

    PubMed Central

    Hmama, Z; Lina, G; Vincent, C; Wijdenes, J; Normier, G; Binz, H; Revillard, J P

    1992-01-01

    The capacity of a K. pneumoniae membrane proteoglycan (Kp-MPG) and four of its chemically defined derivatives to activate human monocytes was studied by measuring immunoreactive IL-1 beta, IL-6 and tumour necrosis factor-alpha (TNF-alpha) in culture supernatants. Monocyte culture supernatants were also tested for their comitogenic activity on concanavalin A-stimulated thymocytes and for their cytotoxic activity on the mouse fibroblastic L929 cell line. The four Kp-MPG derivatives were: (i) an acylpoly(1-3)galactoside (APG); (ii) an APG preparation submitted to acid hydrolysis which removed all fatty acids but left intact the galactose chain of APG (GC-APG); (iii) a preparation obtained by mild alkaline hydrolysis, containing additional ester-linked C14 and C16 fatty acids bound to the APG molecule (EFA-APG); and (iv) a polymer of the latter compound (APG pol). Kp-MPG induced the synthesis of IL-1 beta, IL-6 and TNF-alpha with dose-responses and kinetics similar to those of Salmonella minnesota lipopolysaccharide (Sm-Re-LPS). APG pol and EFA-APG induced the secretion of the three cytokines with lower potency than Kp-MPG or Sm-Re-LPS. APG did not trigger any detectable cytokine production and GC-APG induced only borderline and inconsistent responses. Our data demonstrate the critical role of ester-linked C14 and C16 fatty acids in the triggering of monocyte response to Kp-MPG derivatives. PMID:1628418

  5. Fatty Acid-Derived Biofuels and Chemicals Production in Saccharomyces cerevisiae.

    PubMed

    Zhou, Yongjin J; Buijs, Nicolaas A; Siewers, Verena; Nielsen, Jens

    2014-01-01

    Volatile energy costs and environmental concerns have spurred interest in the development of alternative, renewable, sustainable, and cost-effective energy resources. Environment-friendly processes involving microbes can be used to synthesize advanced biofuels. These fuels have the potential to replace fossil fuels in supporting high-power demanding machinery such as aircrafts and trucks. From an engineering perspective, the pathway for fatty acid biosynthesis is an attractive route for the production of advanced fuels such as fatty acid ethyl esters, fatty alcohols, and alkanes. The robustness and excellent accessibility to molecular genetics make the yeast Saccharomyces cerevisiae a suitable host for the purpose of bio-manufacturing. Recent advances in metabolic engineering, as well as systems and synthetic biology, have now provided the opportunity to engineer yeast metabolism for the production of fatty acid-derived fuels and chemicals. PMID:25225637

  6. Preparation of functional composite materials based on chemically derived graphene using solution process

    NASA Astrophysics Data System (ADS)

    Kim, M.; Hyun, W. J.; Mun, S. C.; Park, O. O.

    2015-04-01

    Chemically derived graphenes were assembled into functional composite materials using solution process from stable solvent dispersion. We have developed foldable electronic circuits on paper substrates using vacuum filtration of graphene nanoplates dispersion and a selective transfer process without need for special equipment. The electronic circuits on paper substrates revealed only a small change in conductance under various folding angles and maintained an electronic path after repetitive folding and unfolding. We also prepared flexible. binder-free graphene paper-like materials by addition of graphene oxide as a film stabilizer. This graphene papers showed outstanding electrical conductivity up to 26,000 S/m and high charge capacity as an anode in lithium-ion battery without any post-treatments. For last case, multi-functional thin film structures of graphene nanoplates were fabricated by using layer-by-layer assembly technique, showing optical transparency, electrical conductivity and enhanced gas barrier property.

  7. Invasive tumors derived from xenotransplanted, immortalized human cells after in vivo exposure to chemical carcinogens.

    PubMed

    Iizasa, T; Momiki, S; Bauer, B; Caamano, J; Metcalf, R; Lechner, J; Harris, C C; Klein-Szanto, A J

    1993-09-01

    Several chemicals that are found in cigarette smoke or diesel oil engine exhausts, such as benzo[a]pyrene (B[a]P) and 1,6-dinitropyrene (DNP) are carcinogenic in experimental animal models. In the present study, we have exposed in vivo the xenotransplanted immortalized human bronchial epithelial cell line BEAS-2B to the ultimate carcinogen of B[a]P, benzo[a]pyrene diolepoxide (BPDE), to DNP or to the benzo[e]pyrene, a less active compound that has tumor-promoting abilities in mouse skin carcinogenesis bioassays. All three compounds were administered using slow-release beeswax pellets. After a 6 month exposure, BPDE produced two tumors in seven transplants, four tumors were seen in 10 transplants treated with DNP and one tumor was observed in five tracheal grafts exposed to B[a]P. All the neoplasms were well-differentiated invasive adenocarcinomas. Tracheal transplants exposed to beeswax without carcinogen did not show any evidence of neoplastic growth, and their luminal surfaces were lined by a single or double layer of cuboidal cells. All lines derived from the adenocarcinomas showed increased in vitro resistance to serum-induced terminal differentiation, gelatinolytic activity, s.c. tumorigenicity and invasive growth in an in vivo assay. When these cell lines were compared with previously described tumor cell lines derived from xenotransplants exposed to cigarette smoke condensate, it became clear that the latter exhibited a more aggressive invasive behavior. Nevertheless treatment with the three chemicals gave rise to tumor cell lines that exhibited a similar invasive behavior in vivo, and were able to penetrate early into the wall of the tracheal transplants in which they were seeded. These data indicate that this system based on xenotransplanted bronchial epithelial cells is a very relevant model to identify human carcinogens and to study mechanisms of bronchogenic cancer pathogenesis. PMID:8403201

  8. Antifungal activities of polyhexamethylene biguanide and polyhexamethylene guanide against the citrus sour rot pathogen Geotrichum citri-aurantii in vitro and in vivo

    Microsoft Academic Search

    Linyan Feng; Fuwang Wu; Jing Li; Yueming Jiang; Xuewu Duan

    2011-01-01

    Polyhexamethylene biguanide (PHMB) and polyhexamethylene guanide (PHMG) are broad-spectrum antibacterial agents. Experiments were conducted to investigate the antifungal activities of PHMB and PHMG against a major citrus sour rot pathogen Geotrichum citri-aurantii both in vitro and in vivo. PHMG and PHMB treatments significantly inhibited arthroconidia germination and mycelial growth of G. citri-aurantii in vitro. PHMG and PHMB at 5mg\\/L inhibited

  9. Derivate

    NSDL National Science Digital Library

    2011-03-16

    In this activity, students input functions in order to calculate the derivative and tangent line of that function. This activity allows students to explore tangent lines of various functions. This activity includes supplemental materials, including background information about the topics covered, a description of how to use the application, and exploration questions for use with the java applet.

  10. Differential reconstructed gene interaction networks for deriving toxicity threshold in chemical risk assessment

    PubMed Central

    2013-01-01

    Background Pathway alterations reflected as changes in gene expression regulation and gene interaction can result from cellular exposure to toxicants. Such information is often used to elucidate toxicological modes of action. From a risk assessment perspective, alterations in biological pathways are a rich resource for setting toxicant thresholds, which may be more sensitive and mechanism-informed than traditional toxicity endpoints. Here we developed a novel differential networks (DNs) approach to connect pathway perturbation with toxicity threshold setting. Methods Our DNs approach consists of 6 steps: time-series gene expression data collection, identification of altered genes, gene interaction network reconstruction, differential edge inference, mapping of genes with differential edges to pathways, and establishment of causal relationships between chemical concentration and perturbed pathways. A one-sample Gaussian process model and a linear regression model were used to identify genes that exhibited significant profile changes across an entire time course and between treatments, respectively. Interaction networks of differentially expressed (DE) genes were reconstructed for different treatments using a state space model and then compared to infer differential edges/interactions. DE genes possessing differential edges were mapped to biological pathways in databases such as KEGG pathways. Results Using the DNs approach, we analyzed a time-series Escherichia coli live cell gene expression dataset consisting of 4 treatments (control, 10, 100, 1000 mg/L naphthenic acids, NAs) and 18 time points. Through comparison of reconstructed networks and construction of differential networks, 80 genes were identified as DE genes with a significant number of differential edges, and 22 KEGG pathways were altered in a concentration-dependent manner. Some of these pathways were perturbed to a degree as high as 70% even at the lowest exposure concentration, implying a high sensitivity of our DNs approach. Conclusions Findings from this proof-of-concept study suggest that our approach has a great potential in providing a novel and sensitive tool for threshold setting in chemical risk assessment. In future work, we plan to analyze more time-series datasets with a full spectrum of concentrations and sufficient replications per treatment. The pathway alteration-derived thresholds will also be compared with those derived from apical endpoints such as cell growth rate. PMID:24268022

  11. Correlation of in Vitro Cytokine Responses with the Chemical Composition of Soil-Derived Particulate Matter

    PubMed Central

    Veranth, John M.; Moss, Tyler A.; Chow, Judith C.; Labban, Raed; Nichols, William K.; Walton, John C.; Watson, John G.; Yost, Garold S.

    2006-01-01

    We treated human lung epithelial cells, type BEAS-2B, with 10–80 ?g/cm2 of dust from soils and road surfaces in the western United States that contained particulate matter (PM) < 2.5 ?m aerodynamic diameter. Cell viability and cytokine secretion responses were measured at 24 hr. Each dust sample is a complex mixture containing particles from different minerals mixed with biogenic and anthropogenic materials. We determined the particle chemical composition using methods based on the U.S. Environmental Protection Agency Speciation Trends Network (STN) and the National Park Service Interagency Monitoring of Protected Visual Environments (IMPROVE) network. The functionally defined carbon fractions reported by the ambient monitoring networks have not been widely used for toxicology studies. The soil-derived PM2.5 from different sites showed a wide range of potency for inducing the release of the proinflammatory cytokines interleukin-6 (IL-6) and IL-8 in vitro. Univariate regression and multivariate redundancy analysis were used to test for correlation of viability and cytokine release with the concentrations of 40 elements, 7 ions, and 8 carbon fractions. The particles showed positive correlation between IL-6 release and the elemental and pyrolyzable carbon fractions, and the strongest correlation involving crustal elements was between IL-6 release and the aluminum:silicon ratio. The observed correlations between low-volatility organic components of soil- and road-derived dusts and the cytokine release by BEAS-2B cells are relevant for investigation of mechanisms linking specific air pollution particle types with the initiating events leading to airway inflammation in sensitive populations. PMID:16507455

  12. Amphiphilic lauryl ester derivatives from aromatic amino acids: significance of chemical architecture in aqueous aggregation properties.

    PubMed

    Vijay, R; Singh, Jasmeet; Baskar, Geetha; Ranganathan, Radha

    2009-10-22

    Lauryl esters of L-tyrosine (LET) and L-phenylalanine (LEP) were, in a previous interface adsorption study, found to adopt very different interfacial conformations. The present study is an investigation of their aqueous aggregation properties with the goal of elucidating the effects of the presence in LET and absence in LEP of the phenolic OH group on their aqueous aggregate structures and micellar conformations of the surfactant monomers. The measured properties included aggregation numbers from time-resolved fluorescence quenching (TRFQ), interface hydration index and microviscosity by electron spin resonance (ESR), chemical shifts of (1)H resonance lines by NMR, and Krafft temperatures and enthalpies of structural transitions by differential scanning calorimetry (DSC). The TRFQ, ESR, and NMR experiments were conducted at various temperatures from 23 to 70 degrees C for various surfactant concentrations from 0.050 to 0.200 M. Markedly different temperature dependences of aggregation number and (1)H NMR chemical shifts are exhibited by LET and LEP micelles. LET and LEP form ionic micelles. The aggregation number of LEP decreases as is characteristic of ionic micelles, but that of LET increases slightly with temperature. The changes with temperature in the NMR chemical shifts and width of the resonance lines are significantly greater for the various LEP protons than for those of LET. The differences in these properties and other fluorescence decay characteristics of fluorophores incorporated into the micelles could be attributed to the difference in the micellar conformations of LET and LEP which are postulated to be similar to that at oil-water interfaces. The phenolic group is hypothesized to be in the micelle-water interface as part of the headgroup in LET micelles, and its location does not change with temperature. On the other hand, in LEP micelles, the phenyl ring is folded into the core overlapping with the flexible hydrophobic chains. The resulting closer proximity between the phenyl ring and the flexible hydrocarbon chain causes interdependence of the phenyl ring and chain proton resonances, leading to the observed temperature dependence of the chemical shifts in LEP. The TRFQ and ESR data are combined together in a molecular space-filling model, referred to as the polar shell model, to derive the geometrical properties of the micelle. The DSC scans in the temperature range 10-55 degrees C showed the presence of distinctly different endotherms for LET and LEP. The Krafft temperatures, K(T), and the enthalpies were determined. The higher K(T) and broader peak of the DSC endotherm of LET as compared to LEP are attributed to the stabilization of fiberlike structures below the Krafft temperature due to its chirality and the hydrogen bonding capability of the phenolic OH and also to the ion-dipole interactions. Thus, all of the observed differences between LET and LEP could be attributed to the difference in their chemical architecture. PMID:19778004

  13. A Forward Chemical Screen in Zebrafish Identifies a Retinoic Acid Derivative with Receptor Specificity

    PubMed Central

    Das, Bhaskar C.; McCartin, Kellie; Liu, Ting-Chun; Peterson, Randall T.; Evans, Todd

    2010-01-01

    Background Retinoids regulate key developmental pathways throughout life, and have potential uses for differentiation therapy. It should be possible to identify novel retinoids by coupling new chemical reactions with screens using the zebrafish embryonic model. Principal Findings We synthesized novel retinoid analogues and derivatives by amide coupling, obtaining 80–92% yields. A small library of these compounds was screened for bioactivity in living zebrafish embryos. We found that several structurally related compounds significantly affect development. Distinct phenotypes are generated depending on time of exposure, and we characterize one compound (BT10) that produces specific cardiovascular defects when added 1 day post fertilization. When compared to retinoic acid (ATRA), BT10 shows similar but not identical changes in the expression pattern of embryonic genes that are known targets of the retinoid pathway. Reporter assays determined that BT10 interacts with all three RAR receptor sub-types, but has no activity for RXR receptors, at all concentrations tested. Conclusions Our screen has identified a novel retinoid with specificity for retinoid receptors. This lead compound may be useful for manipulating components of retinoid signaling networks, and may be further derivatized for enhanced activity. PMID:20368991

  14. Catalytic conversion of biomass pyrolysis-derived compounds with chemical liquid deposition (CLD) modified ZSM-5.

    PubMed

    Zhang, Huiyan; Luo, Mengmeng; Xiao, Rui; Shao, Shanshan; Jin, Baosheng; Xiao, Guomin; Zhao, Ming; Liang, Junyu

    2014-03-01

    Chemical liquid deposition (CLD) with KH550, TEOS and methyl silicone oil as the modifiers was used to modify ZSM-5 and deposit its external acid sites. The characteristics of modified catalysts were tested by catalytic conversion of biomass pyrolysis-derived compounds. The effects of different modifying conditions (deposited amount, temperature, and time) on the product yields and selectivities were investigated. The results show KH550 modified ZSM-5 (deposited amount of 4%, temperature of 20°C and time of 6h) produced the maximum yields of aromatics (24.5%) and olefins (16.5%), which are much higher than that obtained with original ZSM-5 catalyst (18.8% aromatics and 9.8% olefins). The coke yield decreased from 44.1% with original ZSM-5 to 26.7% with KH550 modified ZSM-5. The selectivities of low-molecule-weight hydrocarbons (ethylene and benzene) decreased, while that of higher molecule-weight hydrocarbons (propylene, butylene, toluene, and naphthalene) increased comparing with original ZSM-5. PMID:24413482

  15. Two-Dimensional Carbon Compounds Derived from Graphyne with Chemical Properties Superior to Those of Graphene

    PubMed Central

    Zheng, Jia-Jia; Zhao, Xiang; Zhao, Yuliang; Gao, Xingfa

    2013-01-01

    Computational studies considering both thermodynamic and kinetic aspects revealed that graphyne, a carbon material that has recently been of increasing interest, favours unprecedented homogeneous “in-plane” addition reactions. The addition of dichlorocarbene to the C(sp)-C(sp) bond, a site with outstanding regioselectivity in graphyne, proceeds via a stepwise mechanism. Due to their homogeneous nature, additions occurring at C(sp)-C(sp) bonds yield structurally ordered two-dimensional carbon compounds (2DCCs). 2DCCs have electronic band structures near the Fermi level that are similar to those of graphene and are either electrically semi-conductive or metallic depending on whether the reactions break the hexagonal symmetry. Notably, 2DCCs can be further functionalised through substitution reactions with little damage to the extended ?-electron conjugation system. These results suggest that 2DCCs derived from graphyne have physical properties comparable to those of graphene and chemical properties superior to those of graphene. Therefore, 2DCCs are expected to be better suited to practical applications. PMID:23429350

  16. Two-dimensional carbon compounds derived from graphyne with chemical properties superior to those of graphene.

    PubMed

    Zheng, Jia-Jia; Zhao, Xiang; Zhao, Yuliang; Gao, Xingfa

    2013-01-01

    Computational studies considering both thermodynamic and kinetic aspects revealed that graphyne, a carbon material that has recently been of increasing interest, favours unprecedented homogeneous "in-plane" addition reactions. The addition of dichlorocarbene to the C(sp)-C(sp) bond, a site with outstanding regioselectivity in graphyne, proceeds via a stepwise mechanism. Due to their homogeneous nature, additions occurring at C(sp)-C(sp) bonds yield structurally ordered two-dimensional carbon compounds (2DCCs). 2DCCs have electronic band structures near the Fermi level that are similar to those of graphene and are either electrically semi-conductive or metallic depending on whether the reactions break the hexagonal symmetry. Notably, 2DCCs can be further functionalised through substitution reactions with little damage to the extended ?-electron conjugation system. These results suggest that 2DCCs derived from graphyne have physical properties comparable to those of graphene and chemical properties superior to those of graphene. Therefore, 2DCCs are expected to be better suited to practical applications. PMID:23429350

  17. Chemical Compositional, Biological, and Safety Studies of a Novel Maple Syrup Derived Extract for Nutraceutical Applications

    PubMed Central

    2015-01-01

    Maple syrup has nutraceutical potential given the macronutrients (carbohydrates, primarily sucrose), micronutrients (minerals and vitamins), and phytochemicals (primarily phenolics) found in this natural sweetener. We conducted compositional (ash, fiber, carbohydrates, minerals, amino acids, organic acids, vitamins, phytochemicals), in vitro biological, and in vivo safety (animal toxicity) studies on maple syrup extracts (MSX-1 and MSX-2) derived from two declassified maple syrup samples. Along with macronutrient and micronutrient quantification, thirty-three phytochemicals were identified (by HPLC-DAD), and nine phytochemicals, including two new compounds, were isolated and identified (by NMR) from MSX. At doses of up to 1000 mg/kg/day, MSX was well tolerated with no signs of overt toxicity in rats. MSX showed antioxidant (2,2-diphenyl-1-picrylhydrazyl (DPPH) assay) and anti-inflammatory (in RAW 264.7 macrophages) effects and inhibited glucose consumption (by HepG2 cells) in vitro. Thus, MSX should be further investigated for potential nutraceutical applications given its similarity in chemical composition to pure maple syrup. PMID:24983789

  18. Chemical compositional, biological, and safety studies of a novel maple syrup derived extract for nutraceutical applications.

    PubMed

    Zhang, Yan; Yuan, Tao; Li, Liya; Nahar, Pragati; Slitt, Angela; Seeram, Navindra P

    2014-07-16

    Maple syrup has nutraceutical potential given the macronutrients (carbohydrates, primarily sucrose), micronutrients (minerals and vitamins), and phytochemicals (primarily phenolics) found in this natural sweetener. We conducted compositional (ash, fiber, carbohydrates, minerals, amino acids, organic acids, vitamins, phytochemicals), in vitro biological, and in vivo safety (animal toxicity) studies on maple syrup extracts (MSX-1 and MSX-2) derived from two declassified maple syrup samples. Along with macronutrient and micronutrient quantification, thirty-three phytochemicals were identified (by HPLC-DAD), and nine phytochemicals, including two new compounds, were isolated and identified (by NMR) from MSX. At doses of up to 1000 mg/kg/day, MSX was well tolerated with no signs of overt toxicity in rats. MSX showed antioxidant (2,2-diphenyl-1-picrylhydrazyl (DPPH) assay) and anti-inflammatory (in RAW 264.7 macrophages) effects and inhibited glucose consumption (by HepG2 cells) in vitro. Thus, MSX should be further investigated for potential nutraceutical applications given its similarity in chemical composition to pure maple syrup. PMID:24983789

  19. Gas separation performance of C\\/CMS membranes derived from poly(furfuryl alcohol) (PFA) with different chemical structure

    Microsoft Academic Search

    Chengwen Song; Tonghua Wang; Huawei Jiang; Xiuyue Wang; Yiming Cao; Jieshan Qiu

    2010-01-01

    Carbon molecular sieve (CMS) membranes derived from two kinds of PFAs synthesized by oxalic acid and iodine catalyst were prepared respectively. In order to investigate the effect of chemical structure of the PFAs on properties of their CMS membranes, TG, FTIR, XRD and HRTEM were employed to characterize the microstructural change of CMS membranes during pyrolysis. Gas separation performance of

  20. Partial Atomic Charge Derivation of small molecule Partial atomic charge is very crucial for computing physical, chemical and biological

    E-print Network

    Jayaram, Bhyravabotla

    Partial Atomic Charge Derivation of small molecule Partial atomic charge is very crucial for computing physical, chemical and biological properties, and reactivity of molecules. Through the information of the atomic charge in a given species, it is possible to predict the stability, solvation energetics

  1. Synthesis of an iberiotoxin derivative by chemical ligation: A method for improved yields of cysteine-rich scorpion toxin peptides

    PubMed Central

    Bingham, Jon-Paul; Chun, Joycelyn B.; Ruzicka, Margaret R.; Li, Qing X.; Tan, Zhi-Yong; Kaulin, Yuri A.; Englebretsen, Darren R.; Moczydlowski, Edward G.

    2010-01-01

    Automated and manual solid phase peptide synthesis techniques were combined with chemical ligation to produce a 37-residue peptide toxin derivative of iberiotoxin which contained: (i) substitution of Val16 to Ala, to facilitate kinetic feasibility of native chemical ligation, and; (ii) substitution of Asp19 to orthogonally protected Cys-4-MeOBzl for chemical conjugate derivatization following peptide folding and oxidation. This peptide ligation approach increased synthetic yields approximately 12-fold compared to standard linear peptide synthesis. In a functional inhibition assay, the ligated scorpion toxin derivative, iberiotoxin V16A/D19-Cys-4-MeOBzl, exhibited ‘native-like’ affinity (Kd = 1.9 nM) and specificity towards the BK Ca2+-activated K+ Channel (KCa1.1). This was characterized by the rapid association and slow dissociation rates (kon = 4.59 × 105 M?1 s?1; koff = 8.65 × 10?4 s?1) as determined by inhibition of macroscopic whole-cell currents of cloned human KCa1.1 channel. These results illustrate the successful application of peptide chemical ligation to improve yield of cysteine-rich peptide toxins over traditional solid phase peptide synthesis. Native chemical ligation is a promising method for improving production of biologically active disulfide containing peptide toxins, which have diverse applications in studies of ion-channel function. PMID:19463736

  2. Some benzotriazole derivatives as corrosion inhibitors for copper in acidic medium: Experimental and quantum chemical molecular dynamics approach

    Microsoft Academic Search

    K. F. Khaled; Sahar A. Fadl-Allah; B. Hammouti

    2009-01-01

    Three benzotriazole derivatives namely, 1-(Phenylsulfonyl)-1H-benzotriazole (PSB), 1-(3-Pyridinylsulfonyl)-1H-benzotriazole (3PSB) and 1-(2-Pyridinylsulfonyl)-1H-benzotriazole (2PSB) have been investigated for the corrosion of copper in 1M HNO3 at different concentrations at 25±1°C using chemical (weight loss) and electrochemical (Tafel polarization method) measurements. Generally, inhibition efficiency of the investigated compounds was found to depend on the concentration and the nature of the inhibitors. Quantum chemical calculation

  3. A new non-invasive approach based on polyhexamethylene biguanide increases the regression rate of HPV infection

    PubMed Central

    2012-01-01

    Background HPV infection is a worldwide problem strictly linked to the development of cervical cancer. Persistence of the infection is one of the main factors responsible for the invasive progression and women diagnosed with intraepithelial squamous lesions are referred for further assessment and surgical treatments which are prone to complications. Despite this, there are several reports on the spontaneous regression of the infection. This study was carried out to evaluate the effectiveness of a long term polyhexamethylene biguanide (PHMB)-based local treatment in improving the viral clearance, reducing the time exposure to the infection and avoiding the complications associated with the invasive treatments currently available. Method 100 women diagnosed with HPV infection were randomly assigned to receive six months of treatment with a PHMB-based gynecological solution (Monogin®, Lo.Li. Pharma, Rome - Italy) or to remain untreated for the same period of time. Results A greater number of patients, who received the treatment were cleared of the infection at the two time points of the study (three and six months) compared to that of the control group. A significant difference in the regression rate (90% Monogin group vs 70% control group) was observed at the end of the study highlighting the time-dependent ability of PHMB to interact with the infection progression. Conclusions The topic treatment with PHMB is a preliminary safe and promising approach for patients with detected HPV infection increasing the chance of clearance and avoiding the use of invasive treatments when not strictly necessary. Trial registration ClinicalTrials.gov Identifier NCT01571141 PMID:23009652

  4. An intercomparison and evaluation of aircraft-derived and simulated CO from seven chemical transport models during the TRACE-P

    E-print Network

    Palmer, Paul

    An intercomparison and evaluation of aircraft-derived and simulated CO from seven chemical. Model simulated and measured CO are statistically analyzed along aircraft flight tracks. Results., An intercomparison and evaluation of aircraft-derived and simulated CO from seven chemical transport models during

  5. Increased Peritoneal Dialysis Exit Site Infections Using Topical Antiseptic Polyhexamethylene Biguanide Compared to Mupirocin: Results of a Safety Interim Analysis of an Open-Label Prospective Randomized Study

    PubMed Central

    Findlay, Andrew; Serrano, Charelle; Punzalan, Sally

    2013-01-01

    Prophylactic mupirocin for peritoneal catheter exit sites reduces exit site infection (ESI) risk but engenders antibiotic resistance. We present early interim safety analysis of an open-label randomized study comparing polyhexamethylene biguanide (PHMB) and mupirocin. A total of 106 patients randomized to 53 in each group were followed up for a mean of 12.68 months per patient. On safety analysis, the PHMB group had a significantly greater ESI rate than the mupirocin group (odds ratio [OR], 0.26; 95% confidence interval [CI], 0.09 to 0.80), leading to discontinuation of the trial. PMID:23403425

  6. Increased peritoneal dialysis exit site infections using topical antiseptic polyhexamethylene biguanide compared to mupirocin: results of a safety interim analysis of an open-label prospective randomized study.

    PubMed

    Findlay, Andrew; Serrano, Charelle; Punzalan, Sally; Fan, Stanley L

    2013-05-01

    Prophylactic mupirocin for peritoneal catheter exit sites reduces exit site infection (ESI) risk but engenders antibiotic resistance. We present early interim safety analysis of an open-label randomized study comparing polyhexamethylene biguanide (PHMB) and mupirocin. A total of 106 patients randomized to 53 in each group were followed up for a mean of 12.68 months per patient. On safety analysis, the PHMB group had a significantly greater ESI rate than the mupirocin group (odds ratio [OR], 0.26; 95% confidence interval [CI], 0.09 to 0.80), leading to discontinuation of the trial. PMID:23403425

  7. Primary Cilia: The Chemical Antenna Regulating Human Adipose-Derived Stem Cell Osteogenesis

    PubMed Central

    Bodle, Josephine C.; Rubenstein, Candace D.; Phillips, Michelle E.; Bernacki, Susan H.; Qi, Jie; Banes, Albert J.; Loboa, Elizabeth G.

    2013-01-01

    Adipose-derived stem cells (ASC) are multipotent stem cells that show great potential as a cell source for osteogenic tissue replacements and it is critical to understand the underlying mechanisms of lineage specification. Here we explore the role of primary cilia in human ASC (hASC) differentiation. This study focuses on the chemosensitivity of the primary cilium and the action of its associated proteins: polycystin-1 (PC1), polycystin-2 (PC2) and intraflagellar transport protein-88 (IFT88), in hASC osteogenesis. To elucidate cilia-mediated mechanisms of hASC differentiation, siRNA knockdown of PC1, PC2 and IFT88 was performed to disrupt cilia-associated protein function. Immunostaining of the primary cilium structure indicated phenotypic-dependent changes in cilia morphology. hASC cultured in osteogenic differentiation media yielded cilia of a more elongated conformation than those cultured in expansion media, indicating cilia-sensitivity to the chemical environment and a relationship between the cilium structure and phenotypic determination. Abrogation of PC1, PC2 and IFT88 effected changes in both hASC proliferation and differentiation activity, as measured through proliferative activity, expression of osteogenic gene markers, calcium accretion and endogenous alkaline phosphatase activity. Results indicated that IFT88 may be an early mediator of the hASC differentiation process with its knockdown increasing hASC proliferation and decreasing Runx2, alkaline phosphatase and BMP-2 mRNA expression. PC1 and PC2 knockdown affected later osteogenic gene and end-product expression. PC1 knockdown resulted in downregulation of alkaline phosphatase and osteocalcin gene expression, diminished calcium accretion and reduced alkaline phosphatase enzymatic activity. Taken together our results indicate that the structure of the primary cilium is intimately associated with the process of hASC osteogenic differentiation and that its associated proteins are critical players in this process. Elucidating the dynamic role of the primary cilium and its associated proteins will help advance the application of hASC in generating autologous tissue engineered therapies in critical defect bone injuries. PMID:23690943

  8. Chemical derivation to enhance the chemical/oxidative stability of resorcinol-formaldehyde (R-F) resin

    SciTech Connect

    Hubler, T.L.; Shaw, W.J.; Brown, G.N.; Linehan, J.C.; Franz, J.A.; Hart, T.R.; Hogan, M.O.

    1996-09-01

    Tank wastes at Hanford and SRS contain highly alkaline supernate solutions of conc. Na, K nitrates with large amounts of {sup 137}Cs. It is desirable to remove and concentrate the highly radioactive fraction for vitrification. One candidate ion exchange material for removing the radiocesium is R-F resin. This report summarizes studies into synthesis and characterization of 4-derivatized R-F resins prepared in pursuit of more chemically/oxidatively robust resin. 85% 4-fluororesorcinol/15% phenol formaldehyde resin appears to have good stability in alkaline solution, although there may be some nucleophilic displacement reaction during synthesis; further studies are needed.

  9. Atmospheric Chemical Transport Based on High Resolution Model- Derived Winds: A Case Study

    NASA Technical Reports Server (NTRS)

    Hannan, John R.; Fuelberg, Henry E.; Thompson, Anne M.; Bieberbach, George, Jr.; Knabb, Richard D.; Kondo, Yutaka; Anderson, Bruce E.; Browell, Edward V.; Gregory, Gerald L.; Sachse, Glen; Singh, Hanwant B.

    1999-01-01

    Flight 10 of NASA's Subsonic Assessment (SASS) Ozone and Nitrogen Oxide Experiment (SONEX) extended southwest of Lajes, Azores. A variety of chemical signatures were encountered. These signatures are examined in detail, relating them to meteorological data from a high resolution numerical model having horizontal grid spacing of 30 and 90 km and 26 vertical levels. The meteorological output at hourly intervals is used to create backward trajectories from the locations of the chemical signatures. Four major categories of chemical signatures are discussed-stratospheric, lightning, continental pollution, and a transition layer. The strong stratospheric signal is encountered just south of the Azores in a region of depressed tropopause height. Three chemical signatures at different altitudes in the upper troposphere are attributed to lightning. Backward trajectories arriving at locations of these signatures are related to locations of cloud-to-ground lightning. Results show that the trajectories pass through regions of lightning 1-2 days earlier over the eastern Gulf of Mexico and off the southeast coast of the United States. The lowest leg of the flight exhibits a chemical signature consistent with continental pollution. Trajectories arriving at this signature are found to pass over the highly populated Northeast Corridor of the United States. Surface based pollution apparently is lofted to the altitudes of the trajectories by convective clouds along the East Coast that did not contain lightning. Finally, a chemical transition layer is described. Its chemical signature is intermediate to those of lightning and continental pollution. Trajectories arriving in this layer pass between the trajectories of the lightning and pollution signatures. Thus, they probably are impacted by both sources.

  10. Chemical investigation of commercial grape seed derived products to assess quality and detect adulteration.

    PubMed

    Villani, Tom S; Reichert, William; Ferruzzi, Mario G; Pasinetti, Giulio M; Simon, James E; Wu, Qingli

    2015-03-01

    Fundamental concerns in quality control arise due to increasing use of grape seed extract (GSE) and the complex chemical composition of GSE. Proanthocyanidin monomers and oligomers are the major bioactive compounds in GSE. Given no standardized criteria for quality, large variation exists in the composition of commercial GSE supplements. Using HPLC/UV/MS, 21 commercial GSE containing products were purchased and chemically profiled, major compounds quantitated, and compared against authenticated grape seed extract, peanut skin extract, and pine bark extract. The antioxidant capacity and total polyphenol content for each sample was also determined and compared using standard techniques. Nine products were adulterated, found to contain peanut skin extract. A wide degree of variability in chemical composition was detected in commercial products, demonstrating the need for development of quality control standards for GSE. A TLC method was developed to allow for rapid and inexpensive detection of adulteration in GSE by peanut skin. PMID:25306345

  11. High content screening of defined chemical libraries using normal and glioma-derived neural stem cell lines.

    PubMed

    Danovi, Davide; Folarin, Amos A; Baranowski, Bart; Pollard, Steven M

    2012-01-01

    Small molecules with potent biological effects on the fate of normal and cancer-derived stem cells represent both useful research tools and new drug leads for regenerative medicine and oncology. Long-term expansion of mouse and human neural stem cells is possible using adherent monolayer culture. These cultures represent a useful cellular resource to carry out image-based high content screening of small chemical libraries. Improvements in automated microscopy, desktop computational power, and freely available image processing tools, now means that such chemical screens are realistic to undertake in individual academic laboratories. Here we outline a cost effective and versatile time lapse imaging strategy suitable for chemical screening. Protocols are described for the handling and screening of human fetal Neural Stem (NS) cell lines and their malignant counterparts, Glioblastoma-derived neural stem cells (GNS). We focus on identification of cytostatic and cytotoxic "hits" and discuss future possibilities and challenges for extending this approach to assay lineage commitment and differentiation. PMID:22341231

  12. Transformations of biomass-derived platform molecules: from high added-value chemicals to fuels via aqueous-phase processing.

    PubMed

    Serrano-Ruiz, Juan Carlos; Luque, Rafael; Sepúlveda-Escribano, Antonio

    2011-11-01

    Global warming issues and the medium-term depletion of fossil fuel reserves are stimulating researchers around the world to find alternative sources of energy and organic carbon. Biomass is considered by experts the only sustainable source of energy and organic carbon for our industrial society, and it has the potential to displace petroleum in the production of chemicals and liquid transportation fuels. However, the transition from a petroleum-based economy to one based on biomass requires new strategies since the petrochemical technologies, well-developed over the last century, are not valid to process the biomass-derived compounds. Unlike petroleum feedstocks, biomass derived platform molecules possess a high oxygen content that gives them low volatility, high solubility in water, high reactivity and low thermal stability, properties that favour the processing of these resources by catalytic aqueous-phase technologies at moderate temperatures. This tutorial review is aimed at providing a general overview of processes, technologies and challenges that lie ahead for a range of different aqueous-phase transformations of some of the key biomass-derived platform molecules into liquid fuels for the transportation sector and related high added value chemicals. PMID:21713268

  13. Characterization of Nitrogen-Containing Species in Coal andPetroleum-Derived Products by ammonia Chemical Ionization-High Resolution MassSpectrometry.

    SciTech Connect

    None

    1997-01-01

    A coal-derived light distillate and a petroleum-derived residuum have been studied by high resolution mass spectrometry using both low-pressure ammonia chemical ionization and low-voltage electron impact ionization. A mass calibration mixture for use with ammonia chemical ionization has been developed. Selective ionization of the basic nitrogen-containing compounds by ammonia chemical ionization and compound type characterization of the resulting quasi-molecular species has been demonstrated. Several homologous series of nitrogen-containing compounds were identified in a basic extract by electron impact ionization and compared with quasimolecular analogs identified by ammonia chemical ionization.

  14. An approach for deriving emergency planning zones for chemical munitions emergencies

    Microsoft Academic Search

    John H. Sorensen; Sam A. Carnes; George O. Rogers

    1992-01-01

    The selection of an emergency planning zone {EPZ) for hazardous materials is often a difficult technical as well as a political task. This paper describes a method used in the United States to establish EPZs in the Army's Chemical Stockpile Emergency Preparedness Program. A rationale for a zoned based approach to emergency planning for hazardous materials is developed. The method

  15. Chemical changes due to acid precipitation in a loess-derived soil in central Europe

    Microsoft Academic Search

    B. Ulrich; R. Mayer; P. K. Khanna

    1980-01-01

    In a stand of Fagus silvatica in the Solling highlands, Federal Republic of Germany, we followed the effect of acid precipitation on chemical soil state and the ion fluxes in the ecosystem between 1966 and 1979. As indicated by increasing aluminum concentration in the soil solution and an increase in organic matter storage in the forest floor, for example, the

  16. Chemical Synthesis of beta-Homonojirimycin, of Its N-Butyl Derivative, and of "Methyl Homoazacellobioside"

    PubMed

    Saavedra, Oscar M.; Martin, Olivier R.

    1996-10-01

    beta-Homonojirimycin (2) was prepared by the highly stereoselective double reductive amination of a 2,6-heptodiulose derivative (6 or 13) using ammonium formate and NaBH(3)CN. The process was unsuccessful with primary amines. The synthesis of N-butyl-beta-homonojirimycin (19) was achieved by the N-butanoylation of a derivative of 2 followed by the reduction of the resulting tertiary amide. Compound 19 was found to be completely devoid of anti-HIV activity, in marked contrast with N-butyl-1-deoxynojirimycin. The coupling of the 1-O-p-toluenesulfonyl derivative of 2, compound 20, with methyl 2,3,6-tri-O-benzyl-alpha-D-glucopyranoside, followed by a deprotection step, provided pseudodisaccharide 23, the "homoaza" analog of methyl alpha-cellobioside and a potential inhibitor of beta-glucan-processing enzymes. PMID:11667597

  17. Biogas upgrading by chemical absorption using ammonia rich absorbents derived from wastewater.

    PubMed

    McLeod, Andrew; Jefferson, Bruce; McAdam, Ewan J

    2014-12-15

    The use of ammonia (NH3) rich wastewaters as an ecological chemical absorption solvent for the selective extraction of carbon dioxide (CO2) during biogas upgrading to 'biomethane' has been studied. Aqueous ammonia absorbents of up to 10,000 gNH3 m(-3) demonstrated CO2 absorption rates higher than recorded in the literature for packed columns using 20,000-80,000 g NH3 m(-3) which can be ascribed to the process intensification provided by the hollow fibre membrane contactor used in this study to support absorption. Centrifuge return liquors (2325 g m(-3) ionised ammonium, NH4(+)) and a regenerant (477 gNH4(+) m(-3)) produced from a cationic ion exchanger used to harvest NH4(+) from crude wastewater were also tested. Carbon dioxide fluxes measured for both wastewaters compared reasonably with analogue ammonia absorption solvents of equivalent NH3 concentration. Importantly, this demonstrates that ammonia rich wastewaters can facilitate chemically enhanced CO2 separation which eliminates the need for costly exogenic chemicals or complex chemical handling which are critical barriers to implementation of chemical absorption. When testing NH3 analogues, the potential to recover the reaction product ammonium bicarbonate (NH4HCO3) in crystalline form was also illustrated. This is significant as it suggests a new pathway for ammonia separation which avoids biological nitrification and produces ammonia stabilised into a commercially viable fertiliser (NH4HCO3). However, in real ammonia rich wastewaters, sodium bicarbonate and calcium carbonate were preferentially formed over NH4HCO3 although it is proposed that NH4HCO3 can be preferentially formed by manipulating both ion exchange and absorbent chemistry. PMID:25277752

  18. Nitrophenylated derivatives of epsilon-aminocaproic acid: synthesis and physico-chemical characterization.

    PubMed

    Zharhary, D; Gershon, H

    1977-01-01

    Methods for the synthesis of the mono-, di- and tri-nitro derivatives of epsilon-aminocaproic acid are presented. Special attention is given to the purification procedure, as we have found that methods recommended in the literature do not produce a single product. Evidence is presented which shows that recrystallizing the haptens from hot ethanol produces a by-product which is the ethyl ester of the haptens. Characterization methods and physical properties of the nitro-phenylated derivates of epsilon-aminocaproic acid are summarized. PMID:853226

  19. An overview on chemical aspects and potential health benefits of limonoids and their derivatives

    Microsoft Academic Search

    Rosa Tundis; Monica Rosa Loizzo; Francesco Menichini

    2012-01-01

    Limonoids are heavily oxygenated, modified triterpenes dominant in Meliaceae and Rutaceae plant families. The term limonoid derived from limonin, that was first identified as the bitter constituent of Citrus seeds in 1841. This group of secondary metabolites exhibits a wide range of biological properties including anticancer, antibacterial, antifungal, antimalarial and antiviral activities. Significant progress on the role of limonoids as

  20. Chemicals derived from pyrolysis bio-oils as antioxidants in fuels and lubricants

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Softwood and hardwood lignins and hardwood were pyrolyzed to produce bio-oils to produce lignin-derived bio-oils of which phenols were the major component. These bio-oils were extracted with alkali to yield a range of lignin-related phenols having molecular weights (MWs) from 110 to 344. When tested...

  1. Quantum chemical studies on some imidazole derivatives as corrosion inhibitors for iron in acidic medium

    Microsoft Academic Search

    G Bereket; E Hür; C Ö?retir

    2002-01-01

    In this work, computational studies on some imidazole derivatives which behave as corrosion inhibitors at various levels for iron in hydrochloric acid were carried out in gaseous and aqueous phases using semiemprical methods such as MINDO\\/3, MNDO, PM3 and AM1. Possible correlations between experimentally obtained inhibition efficiencies and calculated highest occupied molecular energy level (EHOMO), lowest unoccupied molecular energy level

  2. Chemically defined conditions for human iPSC derivation and culture

    Microsoft Academic Search

    Guokai Chen; Daniel R Gulbranson; Zhonggang Hou; Jennifer M Bolin; Victor Ruotti; Mitchell D Probasco; Kimberly Smuga-Otto; Sara E Howden; Nicole R Diol; Nicholas E Propson; Ryan Wagner; Garrett O Lee; Jessica Antosiewicz-Bourget; Joyce M C Teng; James A Thomson

    2011-01-01

    We re-examine the individual components for human embryonic stem cell (ESC) and induced pluripotent stem cell (iPSC) culture and formulate a cell culture system in which all protein reagents for liquid media, attachment surfaces and splitting are chemically defined. A major improvement is the lack of a serum albumin component, as variations in either animal- or human-sourced albumin batches have

  3. Electron impact and chemical ionization mass spectral analysis of a volatile uranyl derivative

    SciTech Connect

    Reutter, D.J.; Hardy, D.R.

    1981-01-01

    Quadrupole mass spectral analysis of the volatile uranium ligand complex bis (1,1,1,5,5,5-hexafluoro-2,4-pentanedionato) dioxouranium-di-n-butyl sulfoxide is described utilizing electron impact (EI) and methane chemical ionization (CI) ion sources. All major ions are tentatively identified and the potential usefulness of this complex for determining uranium isotope /sup 235/U//sup 238/U abundance is demonstrated.

  4. The Chemical Nature of Buckminsterfullerene (C_60) and the Characterization of a Platinum Derivative

    Microsoft Academic Search

    Paul J. Fagan; Joseph C. Calabrese; Brian Malone

    1991-01-01

    Little is known about the chemical nature of the recently isolated carbon clusters (C60, C70, C84, and so forth). One potential application of these materials is as highly dispersed supports for metal catalysts, and therefore the question of how metal atoms bind to C60 is of interest. Reaction of C60 with organometallic ruthenium and platinum reagents has shown that metals

  5. Protein Structural Information Derived from NMR Chemical Shift with the Neural Network Program TALOS-N

    PubMed Central

    Shen, Yang; Bax, Ad

    2015-01-01

    Summary Chemical shifts are obtained at the first stage of any protein structural study by NMR spectroscopy. Chemical shifts are known to be impacted by a wide range of structural factors and the artificial neural network based TALOS-N program has been trained to extract backbone and sidechain torsion angles from 1H, 15N and 13C shifts. The program is quite robust, and typically yields backbone torsion angles for more than 90% of the residues, and sidechain ?1 rotamer information for about half of these, in addition to reliably predicting secondary structure. The use of TALOS-N is illustrated for the protein DinI, and torsion angles obtained by TALOS-N analysis from the measured chemical shifts of its backbone and 13C? nuclei are compared to those seen in a prior, experimentally determined structure. The program is also particularly useful for generating torsion angle restraints, which then can be used during standard NMR protein structure calculations. PMID:25502373

  6. Parameter estimation in stochastic chemical kinetic models using derivative free optimization and bootstrapping

    PubMed Central

    Srivastava, Rishi; Rawlings, James B.

    2014-01-01

    Recent years have seen increasing popularity of stochastic chemical kinetic models due to their ability to explain and model several critical biological phenomena. Several developments in high resolution fluorescence microscopy have enabled researchers to obtain protein and mRNA data on the single cell level. The availability of these data along with the knowledge that the system is governed by a stochastic chemical kinetic model leads to the problem of parameter estimation. This paper develops a new method of parameter estimation for stochastic chemical kinetic models. There are three components of the new method. First, we propose a new expression for likelihood of the experimental data. Second, we use sample path optimization along with UOBYQA-Fit, a variant of of Powell’s unconstrained optimization by quadratic approximation, for optimization. Third, we use a variant of Efron’s percentile bootstrapping method to estimate the confidence regions for the parameter estimates. We apply the parameter estimation method in an RNA dynamics model of E. coli. We test the parameter estimates obtained and the confidence regions in this model. The testing of the parameter estimation method demonstrates the efficiency, reliability, and accuracy of the new method. PMID:24920866

  7. Physical and chemical characterization of biochars derived from different agricultural residues

    NASA Astrophysics Data System (ADS)

    Jindo, K.; Mizumoto, H.; Sawada, Y.; Sanchez-Monedero, M. A.; Sonoki, T.

    2014-12-01

    Biochar is widely recognized as an efficient tool for carbon sequestration and soil fertility. The understanding of its chemical and physical properties, which are strongly related to the type of the initial material used and pyrolysis conditions, is crucial to identify the most suitable application of biochar in soil. A selection of organic wastes with different characteristics (e.g., rice husk (RH), rice straw (RS), wood chips of apple tree (Malus pumila) (AB), and oak tree (Quercus serrata) (OB)) were pyrolyzed at different temperatures (400, 500, 600, 700, and 800 °C) in order to optimize the physicochemical properties of biochar as a soil amendment. Low-temperature pyrolysis produced high biochar yields; in contrast, high-temperature pyrolysis led to biochars with a high C content, large surface area, and high adsorption characteristics. Biochar obtained at 600 °C leads to a high recalcitrant character, whereas that obtained at 400 °C retains volatile and easily labile compounds. The biochar obtained from rice materials (RH and RS) showed a high yield and unique chemical properties because of the incorporation of silica elements into its chemical structure. The biochar obtained from wood materials (AB and OB) showed high carbon content and a high absorption character.

  8. Biomass-derived Syngas Utilization for Fuels and Chemicals - Final Report

    Microsoft Academic Search

    David C. Dayton

    2010-01-01

    Executive Summary;\\u000aThe growing gap between petroleum production and demand, mounting environmental concerns,;\\u000aand increasing fuel prices have stimulated intense interest in research and development (R&D) of;\\u000aalternative fuels, both synthetic and bio-derived. Currently, the most technically defined;\\u000athermochemical route for producing alternative fuels from lignocellulosic biomass involves;\\u000agasification\\/reforming of biomass to produce syngas (carbon monoxide [CO] + hydrogen [H2]),;

  9. Correlation between chemical structure and biological activities of Porphyromonas gingivalis synthetic lipopeptide derivatives

    PubMed Central

    Makimura, Y; Asai, Y; Taiji, Y; Sugiyama, A; Tamai, R; Ogawa, T

    2006-01-01

    We recently separated a PG1828-encoded triacylated lipoprotein (Pg-LP), composed of two palmitoyl and one pentadecanoyl groups at the N-terminal of glycerocysteine from Porphyromonas gingivalis, a periodontopathic bacteria, and found that Pg-LP exhibited definite biological activities through Toll-like receptor (TLR) 2. In the present study, we synthesized 12 different Pg-LP N-terminal peptide moieties (PGTP) using four combinations of glyceryl (R and S) and cysteinyl (l and d) stereoisomers, and three different acyl group regioisomers, N-pentadecanoyl derivative (PGTP1), S-glycero 2-pentadecanoyl derivative (PGTP2) and S-glycero 3-pentadecanoyl derivative (PGTP3). All the PGTP compounds (RL, SL, SD, RD) tested showed TLR2-dependent cell activation. The activating capacities of the PGTP-R compounds were more potent than those of the PGTP-S compounds, whereas there were no differences between the PGTP-L and -D compounds. Furthermore, the production of interleukin (IL)-6 following stimulation with the PGTP1-RL, PGTP2-RL and PGTP3-RL compounds was impaired in peritoneal macrophages from TLR2 knock-out (KO), but not those from TLR1 KO or TLR6 KO mice. These results suggest that P. gingivalis triacylated lipopeptides are capable of activating host cells in a TLR2-dependent and TLR1-/TLR6-independent manner, and the fatty acid residue at the glycerol position in the PGTP molecule plays an important role in recognition by TLR2. PMID:16968410

  10. Sorption of heavy metal ions on new metal-ligand complexes chemically derived from Lycopodium clavatum

    SciTech Connect

    Pehlivan, E.; Ersoz, M.; Yildiz, S. [Univ. of Selcuk, Konya (Turkey); Duncan, H.J. [Univ. of Glasgow, Scotland (United Kingdom)

    1994-08-01

    Sorption of heavy metal ions from aqueous solution has been investigated as a function of pH using a novel exchanger system whereby Lycopodium clavatum is functionalized with carboxylate and glyoxime metal-ligand complexes. The new ligand exchangers were prepared using a reaction of diaminosporopollenin with various metal-ligand complexes of glyoxime and monocarboxylic acid. The sorptive behavior of these metal-ligand exchangers and the possibilities to remove and to recover selectively heavy metal cations using these systems are discussed on the basis of their chemical natures and their complexing properties.

  11. Production of a refined biooil derived by fast pyrolysis of chicken manure with chemical and physical characteristics close to those of fossil fuels

    Microsoft Academic Search

    Carlos M. Monreal; Morris Schnitzer

    2011-01-01

    The chemical and physical properties of raw biooils prevent their direct use in combustion engines. We processed raw pyrolytic biooil derived from chicken manure to yield a colorless refined biooil with diesel qualities. Chemical characterization of the refined biooil involved elemental and several spectroscopic analyses. The physical measurements employed were viscosity, density and heat of combustion. The elemental composition (%

  12. Fabrication of large-area arrays of hybrid nanostructures on polymer-derived chemically patterned surfaces

    NASA Astrophysics Data System (ADS)

    Liu, Xiaoying; Nepal, Dhriti; Biswas, Sushmita; Park, Kyoungweon; Vaia, Richard; Nealey, Paul; Air Force Research Laboratories Collaboration; University of Chicago Team

    2014-03-01

    The precise placement and assembly of nanoparticles (NPs) into large-area nanostructure arrays will allow for the design and implementation of advanced nanoscale devices for applications in fields such as quantum computing, optical sensing, superlenses, photocatalysis, photovoltaics, and non-linear optics. Our work is focused on using chemically nanopatterned surfaces to fabricate arrays of hybrid nanostructures with each component of the building block at well-defined positions. The precise chemical contrast patterns with densities and resolution of features created using standard tools of lithography, polymer self-assembly, and surface functionalization allow for control of position and interparticle spacing through selective surface-particle and particle-particle interactions. We have demonstrated the assembly of NPs, including metallic NPs and semiconductor quantum dots, into arrays of hybrid structures with various geometries, such as monomers, dimers, quatrefoils, stripes, and chains. We have developed protocols to fabricate NP arrays over a variety of substrates, which allows for the design and characterization of optical and electronic nanostructures and devices to meet the requirements of various technological applications.

  13. Preparation and characterization of activated carbon derived from the thermo-chemical conversion of chicken manure.

    PubMed

    Koutcheiko, S; Monreal, C M; Kodama, H; McCracken, T; Kotlyar, L

    2007-09-01

    Physico-chemical properties of a bioorganic char were modified by pyrolysis in the presence of NaOH, and with subsequent physical activation of carbonaceous species with CO2 a value-added activated carbon was fabricated. Bioorganic char is produced as a co-product during the production of bio-fuel from the pyrolysis of chicken litter. Untreated char contains approximately 37 wt% of C and approximately 43-45 wt% of inorganic minerals containing K, Ca, Fe, P, Cu, Mg, and Si. Carbonization and chemical activation of the char at 600 degrees C in the presence of NaOH in forming gas (4% H2 balanced with Ar) produced mainly demineralized activated carbon having BET (Brunauer, Emmett, and Teller) surface area of 486 m2/g and average pore size of 2.8 nm. Further physical activation with CO2 at 800 degrees C for 30 min resulted in activated carbon with BET surface area of 788 m2/g and average pore size of 2.2 nm. The mineral content was 10 wt%. X-ray photoelectron spectroscopy (XPS) indicated that the latter activation process reduced the pyrrolic- and/or pyridonic-N, increased pyridinic-N and formed quaternary-N at the expense of pyrrolic- and/or pyridonic-N found in the untreated char. PMID:17098423

  14. Chemical Modeling of Acid-Base Properties of Soluble Biopolymers Derived from Municipal Waste Treatment Materials

    PubMed Central

    Tabasso, Silvia; Berto, Silvia; Rosato, Roberta; Tafur Marinos, Janeth Alicia; Ginepro, Marco; Zelano, Vincenzo; Daniele, Pier Giuseppe; Montoneri, Enzo

    2015-01-01

    This work reports a study of the proton-binding capacity of biopolymers obtained from different materials supplied by a municipal biowaste treatment plant located in Northern Italy. One material was the anaerobic fermentation digestate of the urban wastes organic humid fraction. The others were the compost of home and public gardening residues and the compost of the mix of the above residues, digestate and sewage sludge. These materials were hydrolyzed under alkaline conditions to yield the biopolymers by saponification. The biopolymers were characterized by 13C NMR spectroscopy, elemental analysis and potentiometric titration. The titration data were elaborated to attain chemical models for interpretation of the proton-binding capacity of the biopolymers obtaining the acidic sites concentrations and their protonation constants. The results obtained with the models and by NMR spectroscopy were elaborated together in order to better characterize the nature of the macromolecules. The chemical nature of the biopolymers was found dependent upon the nature of the sourcing materials. PMID:25658795

  15. Chemical vapor deposition-derived graphene with electrical performance of exfoliated graphene.

    PubMed

    Petrone, Nicholas; Dean, Cory R; Meric, Inanc; van der Zande, Arend M; Huang, Pinshane Y; Wang, Lei; Muller, David; Shepard, Kenneth L; Hone, James

    2012-06-13

    While chemical vapor deposition (CVD) promises a scalable method to produce large-area graphene, CVD-grown graphene has heretofore exhibited inferior electronic properties in comparison with exfoliated samples. Here we test the electrical transport properties of CVD-grown graphene in which two important sources of disorder, namely grain boundaries and processing-induced contamination, are substantially reduced. We grow CVD graphene with grain sizes up to 250 ?m to abate grain boundaries, and we transfer graphene utilizing a novel, dry-transfer method to minimize chemical contamination. We fabricate devices on both silicon dioxide and hexagonal boron nitride (h-BN) dielectrics to probe the effects of substrate-induced disorder. On both substrate types, the large-grain CVD graphene samples are comparable in quality to the best reported exfoliated samples, as determined by low-temperature electrical transport and magnetotransport measurements. Small-grain samples exhibit much greater variation in quality and inferior performance by multiple measures, even in samples exhibiting high field-effect mobility. These results confirm the possibility of achieving high-performance graphene devices based on a scalable synthesis process. PMID:22582828

  16. Chemical Derivatives of a Small Molecule Deubiquitinase Inhibitor Have Antiviral Activity against Several RNA Viruses

    PubMed Central

    Gonzalez-Hernandez, Marta J.; Pal, Anupama; Gyan, Kofi E.; Charbonneau, Marie-Eve; Showalter, Hollis D.; Donato, Nicholas J.; O'Riordan, Mary; Wobus, Christiane E.

    2014-01-01

    Most antiviral treatment options target the invading pathogen and unavoidably encounter loss of efficacy as the pathogen mutates to overcome replication restrictions. A good strategy for circumventing drug resistance, or for pathogens without treatment options, is to target host cell proteins that are utilized by viruses during infection. The small molecule WP1130 is a selective deubiquitinase inhibitor shown previously to successfully reduce replication of noroviruses and some other RNA viruses. In this study, we screened a library of 31 small molecule derivatives of WP1130 to identify compounds that retained the broad-spectrum antiviral activity of the parent compound in vitro but exhibited improved drug-like properties, particularly increased aqueous solubility. Seventeen compounds significantly reduced murine norovirus infection in murine macrophage RAW 264.7 cells, with four causing decreases in viral titers that were similar or slightly better than WP1130 (1.9 to 2.6 log scale). Antiviral activity was observed following pre-treatment and up to 1 hour postinfection in RAW 264.7 cells as well as in primary bone marrow-derived macrophages. Treatment of the human norovirus replicon system cell line with the same four compounds also decreased levels of Norwalk virus RNA. No significant cytotoxicity was observed at the working concentration of 5 µM for all compounds tested. In addition, the WP1130 derivatives maintained their broad-spectrum antiviral activity against other RNA viruses, Sindbis virus, LaCrosse virus, encephalomyocarditis virus, and Tulane virus. Thus, altering structural characteristics of WP1130 can maintain effective broad-spectrum antiviral activity while increasing aqueous solubility. PMID:24722666

  17. Chemical derivatives of a small molecule deubiquitinase inhibitor have antiviral activity against several RNA viruses.

    PubMed

    Gonzalez-Hernandez, Marta J; Pal, Anupama; Gyan, Kofi E; Charbonneau, Marie-Eve; Showalter, Hollis D; Donato, Nicholas J; O'Riordan, Mary; Wobus, Christiane E

    2014-01-01

    Most antiviral treatment options target the invading pathogen and unavoidably encounter loss of efficacy as the pathogen mutates to overcome replication restrictions. A good strategy for circumventing drug resistance, or for pathogens without treatment options, is to target host cell proteins that are utilized by viruses during infection. The small molecule WP1130 is a selective deubiquitinase inhibitor shown previously to successfully reduce replication of noroviruses and some other RNA viruses. In this study, we screened a library of 31 small molecule derivatives of WP1130 to identify compounds that retained the broad-spectrum antiviral activity of the parent compound in vitro but exhibited improved drug-like properties, particularly increased aqueous solubility. Seventeen compounds significantly reduced murine norovirus infection in murine macrophage RAW 264.7 cells, with four causing decreases in viral titers that were similar or slightly better than WP1130 (1.9 to 2.6 log scale). Antiviral activity was observed following pre-treatment and up to 1 hour postinfection in RAW 264.7 cells as well as in primary bone marrow-derived macrophages. Treatment of the human norovirus replicon system cell line with the same four compounds also decreased levels of Norwalk virus RNA. No significant cytotoxicity was observed at the working concentration of 5 µM for all compounds tested. In addition, the WP1130 derivatives maintained their broad-spectrum antiviral activity against other RNA viruses, Sindbis virus, LaCrosse virus, encephalomyocarditis virus, and Tulane virus. Thus, altering structural characteristics of WP1130 can maintain effective broad-spectrum antiviral activity while increasing aqueous solubility. PMID:24722666

  18. A quantum chemical study of racemization pathways in substituted chrysene derivatives.

    PubMed

    Kind, Carsten; Götz, Andreas W; Hess, Bernd A

    2003-04-01

    The potential-energy surfaces of 5,11-disubstituted 6,12-dimethoxychrysene and chrysene-6,12-dione derivatives were investigated by means of density functional calculations. We report relative energies of all conformers and an identification of the racemisation pathways of the chiral equilibrium structures. By analysis of homodesmotic reactions we were able to obtain an estimate for the strain energy of the substituted compounds. This strain energy can be used as a means of measuring the steric effects exerted by the substituents. PMID:12658660

  19. Cervicovaginal Safety of the Formulated, Biguanide-Based Human Immunodeficiency Virus Type 1 (HIV-1) Inhibitor NB325 in a Murine Model

    PubMed Central

    Lozenski, Karissa; Kish-Catalone, Tina; Pirrone, Vanessa; Rando, Robert F.; Labib, Mohamed; Wigdahl, Brian; Krebs, Fred C.

    2011-01-01

    Vaginal microbicides that reduce or eliminate the risk of HIV-1 sexual transmission must do so safely without adversely affecting the integrity of the cervicovaginal epithelium. The present studies were performed to assess the safety of the biguanide-based antiviral compound NB325 in a formulation suitable for topical application. Experiments were performed using a mouse model of cervicovaginal microbicide application, which was previously shown to be predictive of topical agent toxicity revealed in microbicide clinical trials. Mice were exposed vaginally to unformulated NB325 or NB325 formulated in the hydroxyethyl cellulose “universal placebo.” Following exposures to formulated 1% NB325 for 10?min to 24?h, the vaginal and cervical epithelia were generally intact, although some areas of minimal vaginal epithelial damage were noted. Although formulated NB325 appeared generally safe for application in these studies, the low but observable level of toxicity suggests the need for improvements in the compound and/or formulation. PMID:22131821

  20. NMR chemical shift as analytical derivative of the Helmholtz free energy.

    PubMed

    Van den Heuvel, Willem; Soncini, Alessandro

    2013-02-01

    We present a theory for the temperature-dependent nuclear magnetic shielding tensor of molecules with arbitrary electronic structure. The theory is a generalization of Ramsey's theory for closed-shell molecules. The shielding tensor is defined as a second derivative of the Helmholtz free energy of the electron system in equilibrium with the applied magnetic field and the nuclear magnetic moments. This derivative is analytically evaluated and expressed as a sum over states formula. Special consideration is given to a system with an isolated degenerate ground state for which the size of the degeneracy and the composition of the wave functions are arbitrary. In this case, the paramagnetic part of the shielding tensor is expressed in terms of the g and A tensors of the electron paramagnetic resonance spin Hamiltonian of the degenerate state. As an illustration of the proposed theory, we provide an explicit formula for the paramagnetic shift of the central lanthanide ion in endofullerenes Ln@C(60), with Ln = Ce(3+), Nd(3+), Sm(3+), Dy(3+), Er(3+), and Yb(3+), where the ground state can be a strongly spin-orbit coupled icosahedral sextet for which the paramagnetic shift cannot be described by previous theories. PMID:23406104

  1. Fluid flow in the Rotorua geothermal field derived from isotopic and chemical data

    SciTech Connect

    Stewart, M.K.; Lyon, G.L.; Robinson, B.W. (DSIR Physical Sciences, Nuclear Sciences Group, P.O. Box 31-132, Lower Hutt (NZ)); Glover, R.B. (DSIR Chemistry, Wairakei, Private Bag, Taupo (NZ))

    1992-04-01

    A wide variety of isotopic and chemical measurements on geothermal fluids from shallow wells at Rotorua have given the following interpretations: The Rotorua field comprises one geothermal system; a primary upflow of (outgassed) alkali chloride water extends from northeast Whakarewarewa to Ngapuna and under Lake Rotorua (east side of the system). At the southern end a secondary upflow discharges dilute alkali chloride water; a second major upflow at Kuirau-Ohinmutu discharges chloride-bicarbonate waters formed by dilution of the primary water and reaction with rock; boiling primary water flows from the eastern upflow zone under confining sediments into aquifers in Rotorua Rhyolite containing chloride-bicarbonate waters in the central region; tritium-bearing groundwater penetrates from overlying aquifers in the sediment into the saddle area between the rhyolite domes or along the crest of the southern rhyolite dome and flows northeast into the northern dome.

  2. The scalability in the mechanochemical syntheses of edge functionalized graphene materials and biomass-derived chemicals.

    PubMed

    Blair, Richard G; Chagoya, Katerina; Biltek, Scott; Jackson, Steven; Sinclair, Ashlyn; Taraboletti, Alexandra; Restrepo, David T

    2014-01-01

    Mechanochemical approaches to chemical synthesis offer the promise of improved yields, new reaction pathways and greener syntheses. Scaling these syntheses is a crucial step toward realizing a commercially viable process. Although much work has been performed on laboratory-scale investigations little has been done to move these approaches toward industrially relevant scales. Moving reactions from shaker-type mills and planetary-type mills to scalable solutions can present a challenge. We have investigated scalability through discrete element models, thermal monitoring and reactor design. We have found that impact forces and macroscopic mixing are important factors in implementing a truly scalable process. These observations have allowed us to scale reactions from a few grams to several hundred grams and we have successfully implemented scalable solutions for the mechanocatalytic conversion of cellulose to value-added compounds and the synthesis of edge functionalized graphene. PMID:25407922

  3. Chemical Characteristics, Synthetic Methods, and Biological Potential of Quinazoline and Quinazolinone Derivatives

    PubMed Central

    2014-01-01

    The heterocyclic fused rings quinazoline and quinazolinone have drawn a huge consideration owing to their expanded applications in the field of pharmaceutical chemistry. Quinazoline and quinazolinone are reported for their diversified biological activities and compounds with different substitutions bring together to knowledge of a target with understanding of the molecule types that might interact with the target receptors. Quinazolines and quinazolinones are considered as an important chemical for the synthesis of various physiological significance and pharmacological utilized molecules. Quinazolines and quinazolinone are a large class of biologically active compounds that exhibited broad spectrum of biological activities such as anti-HIV, anticancer, antifungal, antibacterial, antimutagenic, anticoccidial, anticonvulsant, anti-inflammatory, antidepressant, antimalarial, antioxidant, antileukemic, and antileishmanial activities and other activities. Being considered as advantaged scaffold, the alteration is made with different substituent. PMID:25692041

  4. Physical and chemical characterizations of biochars derived from different agricultural residues

    NASA Astrophysics Data System (ADS)

    Jindo, K.; Mizumoto, H.; Sawada, Y.; Sanchez-Monedero, M. A.; Sonoki, T.

    2014-08-01

    Biochar has received large attention as a strategy to tackle against carbon emission. Not only carbon fixation has been carried out but also other merits for agricultural application due to unique physical and chemical character such as absorption of contaminated compounds in soil, trapping ammonia and methane emission from compost, and enhancement of fertilizer quality. In our study, different local waste feed stocks (rice husk, rice straw, wood chips of apple tree (Malus Pumila) and oak tree (Quercus serrata)), in Aomori, Japan, were utilized for creating biochar with different temperature (400-800 °C). Concerning to the biochar production, the pyrolysis of lower temperature had more biochar yield than higher temperature pyrolysis process. On the contrary, surface areas and adsorption characters have been increased as increasing temperature. The proportions of carbon content in the biochars also increased together with increased temperatures. Infrared-Fourier spectra (FT-IR) and 13C-NMR were used to understand carbon chemical compositions in our biochars, and it was observed that the numbers of the shoulders representing aromatic groups, considered as stable carbon structure appeared as the temperature came closer to 600 °C, as well as in FT-IR. In rice materials, the peak assigned to SiO2, was observed in all biochars (400-800 °C) in FT-IR. We suppose that the pyrolysis at 600 °C creates the most recalcitrant character for carbon sequestration, meanwhile the pyrolysis at 400 °C produces the superior properties as a fertilizer by retaining volatile and easily labile compounds which promotes soil microbial activities.

  5. Laboratory and field evaluations of chemical and plant-derived potential repellents against Culicoides biting midges in northern Spain.

    PubMed

    González, M; Venter, G J; López, S; Iturrondobeitia, J C; Goldarazena, A

    2014-12-01

    The efficacy of 23 compounds in repelling Culicoides biting midges (Diptera: Ceratopogonidae), particularly Culicoides obsoletus (Meigen) females, was determined by means of a Y-tube olfactometer. The 10 most effective compounds were further evaluated in landing bioassays. The six most promising compounds (including chemical and plant-derived repellents) were evaluated at 10% and 25% concentrations in field assays using Centers for Disease Control (CDC) light traps. At least three compounds showed promising results against Culicoides biting midges with the methodologies used. Whereas olfactometer assays indicated DEET at 1?µg/µL to be the most effective repellent, filter paper landing bioassays showed plant-derived oils to be better. Light traps fitted with polyester mesh impregnated with a mixture of octanoic, decanoic and nonanoic fatty acids at 10% and 25% concentrations collected 2.2 and 3.6 times fewer midges than control traps and were as effective as DEET, which is presently considered the reference standard insect repellent. The best plant-derived product was lemon eucalyptus oil. Although these have been reported as safe potential repellents, the present results indicate DEET and the mixture of organic fatty acids to be superior and longer lasting. PMID:25079042

  6. Issues involved in using sol-gel-derived glasses as platforms for chemical sensing

    NASA Astrophysics Data System (ADS)

    Doody, Meagan A.; Baker, Gary A.; Pandey, Siddharth; Bonzagni, Neil J.; Bright, Frank V.

    1999-11-01

    Over the past several years our group has been ex;poring the potential of sol-gel-derived glasses as platforms for advanced sensors and biosensors. In this paper we will outline the challenges that are associated with using these xerogels. Toward this end, we discuss recent results from our laboratories on the performance of polyclonal anti- dansyl antibodies sequestered within a series of xerogels. We assess antibody performance by determining the hapten/antibody association constant, the static excitation and emission for the dansyl hapten bound to the antibody combing site, and the excited-state fluorescence anisotropy and intensity decay kinetics for the dansyl/anti-dansyl system within a series of xerogels.

  7. Femtosecond to second studies of a water-soluble porphyrin derivative in chemical and biological nanocavities.

    PubMed

    Wang, Yilun; Cohen, Boiko; Jicsinszky, Laszlo; Douhal, Abderrazzak

    2012-03-01

    The interactions of 5,10,15,20-tetrakis(4-sulfonatophenyl)-porphyrin (TSPP) with a quaternary ammonium modified ?-cyclodextrin (QA-?-CD) and human serum albumin (HSA) protein in aqueous solutions at pH 7 were studied using steady-state, stopped-flow, and femtosecond to millisecond spectroscopy. TSPP forms 1:1 and 1:2 complexes with QA-?-CD (K(1) = 1.9 × 10(5) M(-1) and K(2) = 7 × 10(3) M(-1)) at 293 K, whereas with the HSA protein only 1:1 complex (K(1) = 1.7 × 10(6) M(-1)) has been found. The chemical and biological nanocavities have notable effects on the fluorescence lifetimes of the Q(x) state (from 9.3 to 11.1 ns in QA-?-CD and 11.6 ns in HSA). Furthermore, the rotational times (400 ps for the free TSPP, 1.6 and 19 ns for QA-?-CD and HSA protein complexes, respectively) clearly indicate the robustness of the formed entities. The confined environment does not affect much the fs dynamics (0.1-0.2 ps) of the encapsulated molecule. However, it clearly affect the ps one (1-2 ps (H(2)O) and 5-10 ps (QA-?-CD and HSA)). The effect of O(2) on the relaxation of the triplet state of the free and encapsulated TSPP is also studied and the obtained results are discussed in light of the shielding effect provided by the chemical and biological cavities. The observed difference, longer triplet lifetime upon encapsulation, might be relevant to the efficiency of this porphyrin in photodynamic therapy. The presteady-state kinetics of the TSPP:HSA has been studied by the stopped-flow spectrometer, and a two-step model was proposed for the complexation processes. The results show the importance of the initial association step for the overall ligand recognition process. This first step occurs with rate constant of ~4 × 10(5) M(-1) s(-1), which is about 5 orders of magnitude larger than the rate constant of the consecutive relaxation processes. We believe that our observations of molecular interaction between TSPP, QA-?-CD, and HSA protein from femtosecond to second at both ground and electronically first excited state give detailed information to improve our understanding of this kind of system and thus for a better design of drug delivery nanocarriers. PMID:22324339

  8. Quantum chemical and statistical study of megazol-derived compounds with trypanocidal activity

    NASA Astrophysics Data System (ADS)

    Rosselli, F. P.; Albuquerque, C. N.; da Silva, A. B. F.

    In this work we performed a structure-activity relationship (SAR) study with the aim to correlate molecular properties of the megazol compound and 10 of its analogs with the biological activity against Trypanosoma cruzi (trypanocidal or antichagasic activity) presented by these molecules. The biological activity indication was obtained from in vitro tests and the molecular properties (variables or descriptors) were obtained from the optimized chemical structures by using the PM3 semiempirical method. It was calculated ˜80 molecular properties selected among steric, constitutional, electronic, and lipophilicity properties. In order to reduce dimensionality and investigate which subset of variables (descriptors) would be more effective in classifying the compounds studied, according to their degree of trypanocidal activity, we employed statistical methodologies (pattern recognition and classification techniques) such as principal component analysis (PCA), hierarchical cluster analysis (HCA), K-nearest neighbor (KNN), and discriminant function analysis (DFA). These methods showed that the descriptors molecular mass (MM), energy of the second lowest unoccupied molecular orbital (LUMO+1), charge on the first nitrogen at substituent 2 (qN'), dihedral angles (D1 and D2), bond length between atom C4 and its substituent (L4), Moriguchi octanol-partition coefficient (MLogP), and length-to-breadth ratio (L/Bw) were the variables responsible for the separation between active and inactive compounds against T. cruzi. Afterwards, the PCA, KNN, and DFA models built in this work were used to perform trypanocidal activity predictions for eight new megazol analog compounds.

  9. Electrochemical nanocomposite-derived sensor for the analysis of chemical oxygen demand in urban wastewaters.

    PubMed

    Gutiérrez-Capitán, Manuel; Baldi, Antoni; Gómez, Raquel; García, Virginia; Jiménez-Jorquera, Cecilia; Fernández-Sánchez, César

    2015-02-17

    This work reports on the fabrication and comparative analytical assessment of electrochemical sensors applied to the rapid analysis of chemical oxygen demand (COD) in urban waste waters. These devices incorporate a carbon nanotube-polystyrene composite, containing different inorganic electrocatalysts, namely, Ni, NiCu alloy, CoO, and CuO/AgO nanoparticles. The sensor responses were initially evaluated using glucose as standard analyte and then by analyzing a set of real samples from urban wastewater treatment plants. The estimated COD values in the samples were compared with those provided by an accredited laboratory using the standard dichromate method. The sensor prepared with the CuO/AgO-based nanocomposite showed the best analytical performance. The recorded COD values of both the sensor and the standard method were overlapped, considering the 95% confidence intervals. In order to show the feasible application of this approach for the detection of COD online and in continuous mode, the CuO/AgO-based nanocomposite sensor was integrated in a compact flow system and applied to the detection of wastewater samples, showing again a good agreement with the values provided by the dichromate method. PMID:25594378

  10. Biomass-derived chemicals: synthesis of biodegradable surfactant ether molecules from hydroxymethylfurfural.

    PubMed

    Arias, Karen S; Climent, Maria J; Corma, Avelino; Iborra, Sara

    2014-01-01

    A new class of biodegradable anionic surfactants with structures based on 5-alkoxymethylfuroate was prepared starting from 5-hydroxymethylfurfural (HMF), through a one-pot-two-steps process which involves the selective etherification of HMF with fatty alcohols using heterogeneous solid acid, followed by a highly selective oxidation of the formyl group with a gold catalyst. The etherification step was optimized using aluminosilicates as acid catalysts with different pore topologies (H-Beta, HY, Mordenite, ZSM-5, ITQ-2, and MCM-41), different active sites (Bronsted or Lewis) and different adsorption properties. It was shown that highly hydrophobic defect-free H-Beta zeolites with Si/Al ratios higher than 25 are excellent acid catalysts to perform the selective etherification of HMF with fatty alcohols, avoiding the competitive self-etherification of HMF. Moreover, the 5-alkoxymethylfurfural derivatives obtained can be selectively oxidized to the corresponding furoic salts in excellent yield using Au/CeO2 as catalyst and air as oxidant, at moderated temperatures. Both H-Beta zeolite and Au/CeO2 could be reused several times without loss of activity. PMID:24106062

  11. Practical silicon deposition rules derived from silane monitoring during plasma-enhanced chemical vapor depositiona)

    NASA Astrophysics Data System (ADS)

    Bartlome, Richard; De Wolf, Stefaan; Demaurex, Bénédicte; Ballif, Christophe; Amanatides, Eleftherios; Mataras, Dimitrios

    2015-05-01

    We clarify the difference between the SiH4 consumption efficiency ? and the SiH4 depletion fraction D, as measured in the pumping line and the actual reactor of an industrial plasma-enhanced chemical vapor deposition system. In the absence of significant polysilane and powder formation, ? is proportional to the film growth rate. Above a certain powder formation threshold, any additional amount of SiH4 consumed translates into increased powder formation rather than into a faster growing Si film. In order to discuss a zero-dimensional analytical model and a two-dimensional numerical model, we measure ? as a function of the radio frequency (RF) power density coupled into the plasma, the total gas flow rate, the input SiH4 concentration, and the reactor pressure. The adjunction of a small trimethylboron flow rate increases ? and reduces the formation of powder, while the adjunction of a small disilane flow rate decreases ? and favors the formation of powder. Unlike ?, D is a location-dependent quantity. It is related to the SiH4 concentration in the plasma cp, and to the phase of the growing Si film, whether the substrate is glass or a c-Si wafer. In order to investigate transient effects due to the RF matching, the precoating of reactor walls, or the introduction of a purifier in the gas line, we measure the gas residence time and acquire time-resolved SiH4 density measurements throughout the ignition and the termination of a plasma.

  12. Microstructural, Chemical and Mechanical Characterization of Polymer-Derived Hi-Nicalon Fibers with Surface Coatings

    NASA Technical Reports Server (NTRS)

    Bansal, Narottam P.; Chen, Yuan L.

    1998-01-01

    Room temperature tensile strengths of as-received Hi-Nicalon fibers and those having BN/SiC, p-BN/SiC, and p-B(Si)N/SiC surface coatings, deposited by chemical vapor deposition, were measured using an average fiber diameter of 13.5 microns. The Weibull statistical parameters were determined for each fiber. The average tensile strength of uncoated Hi-Nicalon on was 3.19 +/- 0.73 GPa with a Weibull modulus of 5.41. Strength of fibers coated with BN/SiC did not change. However, coat with p-BN/SiC and p-B(Si)N/SiC surface layers showed strength loss of approx. 10 and 35 percent, respectively, compared with as-received fibers. The elemental compositions of the fibers and the coatings were analyzed using scanning Auger microprobe and energy dispersive x-ray spectroscopy. The BN coating was contaminated with a large concentration of carbon and some oxygen. In contrast, p-BN, p-B(Si)N, and SiC coatings did not show any contamination. Microstructural analyses of the fibers and the coatings were done by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and selected area electron diffraction. Hi-Nicalon fiber consists of the P-SIC nanocrystals ranging in size from 1 to 30 nm embedded in an amorphous matrix. TEM analysis of the BN coating revealed four distinct layers with turbostatic structure. The p-BN layer was turbostratic and showed considerable preferred orientation. The p-B(Si)N was glassy and the silicon and boron were uniformly distributed. The silicon carbide coating was polycrystalline with a columnar structure along the growth direction. The p-B(Si)N/SiC coatings were more uniform, less defective and of better quality than the BN/SiC or the p-BN/SiC coatings.

  13. Theoretical predictions of chemical degradation reaction mechanisms of RDX and other cyclic nitramines derived from their molecular structures.

    PubMed

    Qasim, M; Fredrickson, H; McGrath, C; Furey, J; Bajpai, R

    2005-06-01

    Analysis of environmental degradation pathways of contaminants is aided by predictions of likely reaction mechanisms and intermediate products derived from computational models of molecular structure. Quantum mechanical methods and force-field molecular mechanics were used to characterize cyclic nitramines. Likely degradation mechanisms for hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) include hydroxylation utilizing addition of hydroxide ions to initiate proton abstraction via 2nd order rate elimination (E2) or via nucleophilic substitution of nitro groups, reductive chemical and biochemical degradation, and free radical oxidation. Due to structural similarities, it is predicted that, under homologous circumstances, certain RDX environmental degradation pathways should also be effective for octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) and similar cyclic nitramines. Computational models provided a theoretical framework whereby likely transformation mechanisms and transformation products of cyclic nitramines were predicted and used to elucidate in situ degradation pathways. PMID:15804809

  14. Impact of climate and parent material on chemical weathering in Loess-derived soils of the Mississippi River valley

    USGS Publications Warehouse

    Muhs, D.R.; Bettis, E. Arthur, III; Been, J.; McGeehin, J.P.

    2001-01-01

    Peoria Loess-derived soils on uplands east of the Mississippi River valley were studied from Louisiana to Iowa, along a south-to-north gradient of decreasing precipitation and temperature. Major element analyses of deep loess in Mississippi and Illinois show that the composition of the parent material is similar in the northern and southern parts of the valley. We hypothesized that in the warmer, wetter parts of the transect, mineral weathering should be greater than in the cooler, drier parts of the transect. Profile average values of CaO/TiO2, MgO/ TiO2, K2O/TiO2, and Na2O/TiO2, Sr/Zr, Ba/Zr, and Rb/Zr represent proxies for depletion of loess minerals such as calcite, dolomite, hornblende, mica, and plagioclase. All ratios show increases from south to north, supporting the hypothesis of greater chemical weathering in the southern part of the valley. An unexpected result is that profile average values of Al2O3/TiO2 and Fe2O3/TiO2 (proxies for the relative abundance of clay minerals) show increases from south to north. This finding, while contrary to the evidence of greater chemical weathering in the southern part of the transect, is consistent with an earlier study which showed higher clay contents in Bt horizons of loess-derived soils in the northern part of the transect. We hypothesize that soils in the northern part of the valley received fine-grained loess from sources to the west of the Mississippi River valley either late in the last glacial period, during the Holocene or both. In contrast, soils in the southern part of the valley were unaffected by such additions.

  15. Amphiphilic 1-deoxynojirimycin derivatives through click strategies for chemical chaperoning in N370S Gaucher cells.

    PubMed

    Diot, Jennifer D; Garcia Moreno, Isabel; Twigg, Gabriele; Ortiz Mellet, Carmen; Haupt, Karsten; Butters, Terry D; Kovensky, José; Gouin, Sébastien G

    2011-10-01

    In Gaucher disease (GD), mutant ?-glucocerebrosidases (?-GCase) that are misfolded are recognized by the quality control machinery of the endoplasmic reticulum (ER) and degraded proteolytically. Hydrophobic iminosugars can be used as pharmacological chaperones to provide an improvement in the folding of the enzyme and promote trafficking from the ER. We have developed here an efficient click procedure to tether hydrophobic substituents to N-azidopropyl-1-deoxynojirimycin. A set of 14 original iminosugars was designed and evaluated for inhibition of commercially available glucosidases. Most of the compounds were micromolar inhibitors of those enzymes. In vitro inhibition assays with the N370S ?-GCase revealed that the sublibrary containing the derivatives with aromatic aglycons displayed the highest inhibitory potency. Chaperone activity of the whole set of synthetic compounds was also explored in mutant Gaucher cells. The most active compound gave a nearly 2-fold increase in enzyme activity at 20 ?M, a significantly higher value than the 1.33-fold recorded for the reference compound N-nonyl-1-deoxynojirimycin (N-nonyl-DNJ). As previously reported with bicyclic sp(2)-iminosugars (Luan, Z.; Higaki, K.; Aguilar-Moncayo, M.; Ninomiya, H.; Ohno, K.; Garci?a-Moreno, M. I.; Ortiz Mellet, C.; Garci?a Ferna?ndez, J. M.; Suzuki, Y. ChemBioChem 2009, 10, 2780), in vitro inhibition of ?-GCase measured for the compounds did not correlate with the cellular chaperone activity. The potency of new iminosugar chaperones is therefore not predictable from structure-activity relationships studies based on the in vitro ?-GCase inhibition. PMID:21830816

  16. Molecular dynamics simulation and quantum chemical calculations for the adsorption of some Azo-azomethine derivatives on mild steel

    NASA Astrophysics Data System (ADS)

    Shokry, H.

    2014-02-01

    The adsorption mechanism and inhibition performance of some Azo-azomethine derivatives [2-hydroxyphenylazo-2?,4?-dihydroxy-3?-formylbenzene(Azo-1), 2-carboxyphenylazo-2?,4?-dihydroxy-3?-formylbenzene (Azo-II), 2-hydroxyphenylazo-2?,4?-dihydroxy-3?-{2-hydroxyphenylazomethine}(Azo-I-azomethine I) and 2-carboxyphenylazo-2?,4?-dihydroxy-3?-{2-hydroxyazo methane} (Azo-II-azomethine II) on mild steel at temperatures ranging from 298 K to 333 K have been studied using molecular dynamics (MD) simulation and quantum chemical computational methods. The results obtained revealed that these molecules could effectively adsorb on Fe (0 0 1) surface and the active adsorption sites of these molecules are the nitrogen, oxygen atoms and special negatively charged carbon atoms. All the inhibitors studied had unique corrosion inhibition performance with Azo-II-azomethine II showing the highest inhibition performance at lower temperature ranges from 298 K to 313 K and Azo-II displaying the highest inhibition performance at higher temperature ranges of 323 K and 333 K. Some quantum chemical parameters and the Mulliken charge densities on the optimized structure of inhibitors were calculated using the 6-31?G basis set method to provide further insight into the mechanism of the corrosion inhibition process. The local reactivity was analyzed through the Fukui function and condensed softness indices in order to know the possible sites of nucleophillic and electrophillic attacks.

  17. Maternally derived chemical defences are an effective deterrent against some predators of poison frog tadpoles (Oophaga pumilio)

    PubMed Central

    Stynoski, Jennifer L.; Shelton, Georgia; Stynoski, Peter

    2014-01-01

    Parents defend their young in many ways, including provisioning chemical defences. Recent work in a poison frog system offers the first example of an animal that provisions its young with alkaloids after hatching or birth rather than before. But it is not yet known whether maternally derived alkaloids are an effective defence against offspring predators. We identified the predators of Oophaga pumilio tadpoles and conducted laboratory and field choice tests to determine whether predators are deterred by alkaloids in tadpoles. We found that snakes, spiders and beetle larvae are common predators of O. pumilio tadpoles. Snakes were not deterred by alkaloids in tadpoles. However, spiders were less likely to consume mother-fed O. pumilio tadpoles than either alkaloid-free tadpoles of the red-eyed treefrog, Agalychnis callidryas, or alkaloid-free O. pumilio tadpoles that had been hand-fed with A. callidryas eggs. Thus, maternally derived alkaloids reduce the risk of predation for tadpoles, but only against some predators. PMID:24850895

  18. Design, synthesis, and physico-chemical interactions of bile acid derived dimeric phospholipid amphiphiles with model membranes.

    PubMed

    Kumar, Sandeep; Bhargava, Priyanshu; Sreekanth, Vedagopuram; Bajaj, Avinash

    2015-06-15

    Understanding of amphiphile-membrane interactions is crucial in design and development of novel amphiphiles for drug delivery, gene therapy, and biomedical applications. Structure and physico-chemical properties of amphiphiles determine their interactions with biomembranes thereby influencing their drug delivery efficacies. Here, we unravel the interactions of bile acid derived dimeric phospholipid amphiphiles with model membranes using Laurdan-based hydration, DPH-based membrane fluidity, and differential scanning calorimetry studies. We synthesized three dimeric bile acid amphiphiles where lithocholic acid, deoxycholic acid, and cholic acid are conjugated to cholic acid phospholipid using click chemistry. Interactions of these dimeric amphiphiles with model membranes showed that these amphiphiles form different structural assemblies and molecular packing in model membranes depending on the number and position of free hydroxyl groups on bile acids. We discovered that cholic acid-cholic acid dimeric phospholipid form self-assembled aggregates in model membranes without changing membrane fluidity; whereas cholic acid-deoxycholic acid derived amphiphile induces membranes fluidity and hydration of model membranes. PMID:25746193

  19. Chemical composition and insecticidal activity against Sitophilus zeamais of the essential oils derived from Artemisia giraldii and Artemisia subdigitata.

    PubMed

    Chu, Sha-Sha; Liu, Zhi-Long; Du, Shu-Shan; Deng, Zhi-Wei

    2012-01-01

    The aim of this research was to determine the chemical composition and insecticidal activity of the essential oils derived from flowering aerial parts of Artemisia giraldii Pamp. and A. subdigitata Mattf. (Family: Asteraceae) against the maize weevil (Sitophilus zeamais Motsch.). Essential oils of aerial parts of A. giraldii and A. subdigitata were obtained from hydrodistillation and investigated by GC and GC-MS. A total of 48 and 33 components of the essential oils of A. giraldii and A. subdigitata were identified, respectively. The principal compounds in A. giraldii essential oil were ?-pinene (13.18%), iso-elemicin (10.08%), germacrene D (5.68%), 4-terpineol (5.43%) and (Z)-?-ocimene (5.06%). 1,8-Cineole (12.26%) and ?-curcumene (10.77%) were the two main components of the essential oil of A. subdigitata, followed by ?-pinene (7.38%), borneol (6.23%) and eugenol (5.87%). The essential oils of A. giraldii and A. subdigitata possessed fumigant toxicity against the maize weevils with LC50 values of 6.29 and 17.01 mg/L air, respectively. The two essential oils of A. giraldii and A. subdigitata also exhibited contact toxicity against S. zeamais adults with LD50 values of 40.51 and 76.34 ?g/adult, respectively. The results indicated that the two essential oils show potential in terms of fumigant and contact toxicity against grain storage insects. PMID:22695231

  20. Gene expression signatures in CD34+-progenitor-derived dendritic cells exposed to the chemical contact allergen nickel sulfate

    SciTech Connect

    Schoeters, Elke [Centre of Expertise in Environmental Toxicology, Flemish Institute for Technological Research (VITO), Boeretang 200, 2400 Mol (Belgium)]. E-mail: elke.schoeters@vito.be; Nuijten, Jean-Marie [Centre of Expertise in Environmental Toxicology, Flemish Institute for Technological Research (VITO), Boeretang 200, 2400 Mol (Belgium); Heuvel, Rosette L. van den [Centre of Expertise in Environmental Toxicology, Flemish Institute for Technological Research (VITO), Boeretang 200, 2400 Mol (Belgium); Nelissen, Inge [Centre of Expertise in Environmental Toxicology, Flemish Institute for Technological Research (VITO), Boeretang 200, 2400 Mol (Belgium); Witters, Hilda [Centre of Expertise in Environmental Toxicology, Flemish Institute for Technological Research (VITO), Boeretang 200, 2400 Mol (Belgium); Schoeters, Greet E.R. [Centre of Expertise in Environmental Toxicology, Flemish Institute for Technological Research (VITO), Boeretang 200, 2400 Mol (Belgium); Tendeloo, Vigor F.I. van [Laboratory of Experimental Hematology, Antwerp University Hospital (UZA), Wilrijkstraat 10, 2650 Edegem (Belgium); Berneman, Zwi N. [Laboratory of Experimental Hematology, Antwerp University Hospital (UZA), Wilrijkstraat 10, 2650 Edegem (Belgium); Verheyen, Geert R. [Centre of Expertise in Environmental Toxicology, Flemish Institute for Technological Research (VITO), Boeretang 200, 2400 Mol (Belgium)

    2006-10-01

    The detection of the sensitizing potential of chemicals is of great importance to industry. A promising in vitro alternative to the currently applied animal assays for sensitization testing makes use of dendritic cells (DCs) that have the capability to process and present antigens to naive T cells and induce their proliferation. Here, we studied changes in gene expression profiles after exposing DCs to the contact allergen nickel sulfate. CD34+-progenitor-derived DCs, initiated from 3 different donors, were exposed to 60 {mu}M nickel sulfate, during 0.5, 1, 3, 6, 12 and 24 h. cDNA microarrays were used to assess the transcriptional activity of about 11,000 genes. Significant changes in the expression of 283 genes were observed; 178 genes were up-regulated and 93 down-regulated. These genes were involved in metabolism, cell structure, immune response, transcription, signal transduction, transport, and apoptosis. No functional information was found for 74 genes. Real-time RT-PCR was used to confirm the microarray results of 12 genes. In addition, 3 DC maturation markers not present on the microarrays (DEC205, DC LAMP and CCR7) were analyzed using real-time RT-PCR and found to be up-regulated at several time points. Our data indicate that a broad range of biological processes is influenced by nickel. Some processes are clearly linked to the immune response and DC maturation, others may indicate a toxic effect of nickel.

  1. Toxic inhibition of smooth muscle contractility by plant-derived sesquiterpenes caused by their chemically reactive alpha-methylenebutyrolactone functions.

    PubMed

    Hay, A J; Hamburger, M; Hostettmann, K; Hoult, J R

    1994-05-01

    1. Previous studies have shown that extracts of feverfew (Tanacetum parthenium) and parthenolide, a sesquiterpene alpha-methylenebutyrolactone obtained from it, inhibit smooth muscle contractility in a time-dependent, non-specific and irreversible manner. 2. The hypothesis that this toxic effect is due specifically to the presence in the sesquiterpene lactone of the potentially reactive alpha-methylene function was tested on rabbit isolated aortic ring preparations. This was done (a) by comparing the effects of two plant-derived sesquiterpene lactones purified from yellow star thistle (Centaurea solstitialis): cynaropicrin (an alpha-methylenebutyrolactone) and solstitialin 13-acetate (lacking the alpha-methylene function), and (b) by chemically inactivating the alpha-methylene functions in cynaropicrin and parthenolide by reaction with cysteine. 3. The results show that the characteristic smooth muscle inhibitory profile is demonstrated by the two alpha-methylenebutyrolactones (parthenolide and cynaropicrin), but not by the compound lacking this functional group (solstitialin 13-acetate), or by those previously active compounds in which it has been inactivated with cysteine. 4. Thus the alpha-methylene function is critical for this aspect of the toxic pharmacological profile of the sesquiterpene butyrolactones, which are natural products widely distributed in the Compositae family of flowering plants. PMID:8032668

  2. Toxic inhibition of smooth muscle contractility by plant-derived sesquiterpenes caused by their chemically reactive alpha-methylenebutyrolactone functions.

    PubMed Central

    Hay, A. J.; Hamburger, M.; Hostettmann, K.; Hoult, J. R.

    1994-01-01

    1. Previous studies have shown that extracts of feverfew (Tanacetum parthenium) and parthenolide, a sesquiterpene alpha-methylenebutyrolactone obtained from it, inhibit smooth muscle contractility in a time-dependent, non-specific and irreversible manner. 2. The hypothesis that this toxic effect is due specifically to the presence in the sesquiterpene lactone of the potentially reactive alpha-methylene function was tested on rabbit isolated aortic ring preparations. This was done (a) by comparing the effects of two plant-derived sesquiterpene lactones purified from yellow star thistle (Centaurea solstitialis): cynaropicrin (an alpha-methylenebutyrolactone) and solstitialin 13-acetate (lacking the alpha-methylene function), and (b) by chemically inactivating the alpha-methylene functions in cynaropicrin and parthenolide by reaction with cysteine. 3. The results show that the characteristic smooth muscle inhibitory profile is demonstrated by the two alpha-methylenebutyrolactones (parthenolide and cynaropicrin), but not by the compound lacking this functional group (solstitialin 13-acetate), or by those previously active compounds in which it has been inactivated with cysteine. 4. Thus the alpha-methylene function is critical for this aspect of the toxic pharmacological profile of the sesquiterpene butyrolactones, which are natural products widely distributed in the Compositae family of flowering plants. PMID:8032668

  3. Influence of oxide impurities on the chemical tuning of the thermoelectric properties of substitution derivatives of RuIn3

    NASA Astrophysics Data System (ADS)

    Wagner-Reetz, Maik; Cardoso-Gil, Raul; Schmidt, Marcus; Grin, Yuri

    2014-07-01

    A systematic investigation on tuning the charge carrier concentration by substitution of the Ru position in RuIn3 is performed. Samples with nominal composition Ru0.95T0.05In3 (T=Re, Rh, Ir) were synthesized via liquid-solid-reaction and subsequent spark plasma sintering treatment. The chemical composition was characterized by X-ray, metallographic and microstructure analysis revealing solid solutions in the samples with Rh and Ir, whereas Re cannot be incorporated in RuIn3. Minor oxide impurities in the commercially available starting elements, the homogeneity range of RuIn3 and the redox potentials of the participating elements are the key for interpreting the observed lattice parameters and the corresponding composition. Both, substitutions with Rh or Ir and Re inclusions in RuIn3 lead independently to a significant decrease of the total thermal conductivity down to approximately one half of the value observed for binary RuIn3, prepared with commercially available starting materials. The electrical resistivity was reduced by substitution and the temperature dependence changes from semiconductor-like, for RuIn3, to metal-like in the substitution derivatives. At the same time the sign change in the thermopower at high temperatures, characteristic for binary RuIn3, is suppressed, attaining only electrons as majority carriers.

  4. QUANTITATION OF MONOSACCHARIDE ISOTOPIC ENRICHMENT IN PHYSIOLOGIC FLUIDS BY ELECTRON IONIZATION OR NEGATIVE CHEMICAL IONIZATION GC/MS USING DI-O-ISOPROPYLIDENE DERIVATIVES.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The aldonitrile pentaacetate and other derivatives lack ions in the electron ionization (EI) spectra possessing an intact hexose structure and thus must be analyzed by chemical ionization GC/MS in order to study multiple isotopomers. We report methods for quantitation of hexose di-O-isopropylidene a...

  5. Disruption of BASIGIN decreases lactic acid export and sensitizes non-small cell lung cancer to biguanides independently of the LKB1 status.

    PubMed

    Granja, Sara; Marchiq, Ibtissam; Le Floch, Renaud; Moura, Conceição Souto; Baltazar, Fátima; Pouysségur, Jacques

    2015-03-30

    Most cancers rely on aerobic glycolysis to generate energy and metabolic intermediates. To maintain a high glycolytic rate, cells must efficiently export lactic acid through the proton-coupled monocarboxylate transporters (MCT1/4). These transporters require a chaperone, CD147/BASIGIN (BSG) for trafficking to the plasma membrane and function.To validate the key role of these transporters in lung cancer, we first analysed the expression of MCT1/4 and BSG in 50 non-small lung cancer (NSCLC) cases. These proteins were specifically upregulated in tumour tissues. We then disrupted BSG in three NSCLC cell lines (A549, H1975 and H292) via 'Zinc-Finger Nucleases'. The three homozygous BSG-/- cell lines displayed a low MCT activity (10- to 5-fold reduction, for MCT1 and MCT4, respectively) compared to wild-type cells. Consequently, the rate of glycolysis, compared to the wild-type counterpart, was reduced by 2.0- to 3.5-fold, whereas the rate of respiration was stimulated in BSG-/- cell lines. Both wild-type and BSG-null cells were extremely sensitive to the mitochondria inhibitor metformin/phenformin in normoxia. However, only BSG-null cells, independently of their LKB1 status, remained sensitive to biguanides in hypoxia in vitro and tumour growth in nude mice. Our results demonstrate that inhibiting glycolysis by targeting lactic acid export sensitizes NSCLC to phenformin. PMID:25894929

  6. Disruption of BASIGIN decreases lactic acid export and sensitizes non-small cell lung cancer to biguanides independently of the LKB1 status

    PubMed Central

    Floch, Renaud Le; Moura, Conceição Souto

    2015-01-01

    Most cancers rely on aerobic glycolysis to generate energy and metabolic intermediates. To maintain a high glycolytic rate, cells must efficiently export lactic acid through the proton-coupled monocarboxylate transporters (MCT1/4). These transporters require a chaperone, CD147/BASIGIN (BSG) for trafficking to the plasma membrane and function. To validate the key role of these transporters in lung cancer, we first analysed the expression of MCT1/4 and BSG in 50 non-small lung cancer (NSCLC) cases. These proteins were specifically upregulated in tumour tissues. We then disrupted BSG in three NSCLC cell lines (A549, H1975 and H292) via ‘Zinc-Finger Nucleases’. The three homozygous BSG?/? cell lines displayed a low MCT activity (10- to 5-fold reduction, for MCT1 and MCT4, respectively) compared to wild-type cells. Consequently, the rate of glycolysis, compared to the wild-type counterpart, was reduced by 2.0- to 3.5-fold, whereas the rate of respiration was stimulated in BSG?/? cell lines. Both wild-type and BSG-null cells were extremely sensitive to the mitochondria inhibitor metformin/phenformin in normoxia. However, only BSG-null cells, independently of their LKB1 status, remained sensitive to biguanides in hypoxia in vitro and tumour growth in nude mice. Our results demonstrate that inhibiting glycolysis by targeting lactic acid export sensitizes NSCLC to phenformin. PMID:25894929

  7. Trends and interactions of physical and bio-geo-chemical features in the Adriatic Sea as derived from satellite observations.

    PubMed

    Barale, Vittorio; Schiller, Christian; Tacchi, Ruggero; Marechal, Cecile

    2005-12-15

    Time series of satellite data, generated by the AVHRR (1981-1999), CZCS (1979-1985) and SeaWiFS (1998-2002), have been used to assess trends and interactions of physical and bio-geo-chemical features in the Adriatic Sea. The images were processed to estimate Sea Surface Temperature (SST) and Chlorophyll-like Pigment Concentration (CPC). Long-term composites and climatologies were derived, using fixed geographical grids and projections. The AVHRR data show an apparent warming trend, when plotting the sequence of seasonal cycles (monthly mean SST, averaged over the whole basin) against time, due to a steady rise of summer values. Considering 3 regions (north, central and south), split into east and west sections, the northern Adriatic shows high SST fluctuations (possibly associated with the cycle of winter cooling and summer warming, typical of the relatively shallow sub-basin), while the southern Adriatic exhibits a lower variability (possibly influenced by the periodic water incoming from, and outflowing to the Ionian Sea). During summer, an east-west gradient prevails, while during winter only a general north-south gradient can be found. The SeaWiFS-derived CPC values, distributions and trends appear to be consistent with the historical CZCS record. Persistent differences in the quantitative assessment of CPC for coastal waters is due to the use of improved algorithms, less influenced by the presence of dissolved organics and suspended sediments in the water column, for the processing of SeaWiFS data. Apparent incongruities of the space and time patterns in the SeaWiFS record with respect to the reference climatology, obtained by CZCS more than a decade before, occur chiefly when considering the spring bloom in the southern Adriatic and the summer development of the north Adriatic front. The comparison of the long-term times series of satellite data shows that there is a high correlation between patterns in the thermal field and in the colour field. This suggests that different surface waters, identified by the SST index, are also traced by different ecological features, identified by the CPC index. Both indices also show a high correlation with the classical cyclonic circulation scheme of the Adriatic Sea, proposing once again an intimate relationship between the water dynamics and its bio-geo-chemistry. PMID:16271746

  8. The resistance of the yeast Saccharomyces cerevisiae to the biocide polyhexamethylene biguanide: involvement of cell wall integrity pathway and emerging role for YAP1

    PubMed Central

    2011-01-01

    Background Polyhexamethylene biguanide (PHMB) is an antiseptic polymer that is mainly used for cleaning hospitals and pools and combating Acantamoeba infection. Its fungicide activity was recently shown by its lethal effect on yeasts that contaminate the industrial ethanol process, and on the PE-2 strain of Saccharomyces cerevisiae, one of the main fermenting yeasts in Brazil. This pointed to the need to know the molecular mechanism that lay behind the cell resistance to this compound. In this study, we examined the factors involved in PHMB-cell interaction and the mechanisms that respond to the damage caused by this interaction. To achieve this, two research strategies were employed: the expression of some genes by RT-qPCR and the analysis of mutant strains. Results Cell Wall integrity (CWI) genes were induced in the PHMB-resistant Saccharomyces cerevisiae strain JP-1, although they are poorly expressed in the PHMB-sensitive Saccharomyces cerevisiae PE2 strain. This suggested that PHMB damages the glucan structure on the yeast cell wall. It was also confirmed by the observed sensitivity of the yeast deletion strains, ?slg1, ?rom2, ?mkk2, ?slt2, ?knr4, ?swi4 and ?swi4, which showed that the protein kinase C (PKC) regulatory mechanism is involved in the response and resistance to PHMB. The sensitivity of the ?hog1 mutant was also observed. Furthermore, the cytotoxicity assay and gene expression analysis showed that the part played by YAP1 and CTT1 genes in cell resistance to PHMB is unrelated to oxidative stress response. Thus, we suggested that Yap1p can play a role in cell wall maintenance by controlling the expression of the CWI genes. Conclusion The PHMB treatment of the yeast cells activates the PKC1/Slt2 (CWI) pathway. In addition, it is suggested that HOG1 and YAP1 can play a role in the regulation of CWI genes. PMID:21854579

  9. Rapid routes of synthesis of chemically reactive and highly radioactively labeled alpha- and beta-oligonucleotide derivatives for in vivo studies

    SciTech Connect

    Boutorine, A.S.; Le Doan, T.; Battioni, J.P.; Mansuy, D.; Dupre, D.; Helene, C. (Museum National d'Histoire Naturelle, Paris (France))

    1990-09-01

    Development of the antisense oligonucleotide strategy for the regulation of gene expression in vivo poses several problems: the stability of oligonucleotides toward intracellular nucleases, labeling of oligonucleotides with high specific radioactivity, improvements of penetration of oligonucleotides into living cells, and enhancement of antisense action by coupling of chemically active groups. In the present paper synthesis of highly radioactively labeled (32P)- and (35S)oligonucleotide derivatives is described starting from both natural (beta) and nuclease-resistant (alpha) anomers of oligonucleotides. Conditions for preparative phosphorylation and thiophosphorylation suitable for oligonucleotides of various lengths, base composition, and anomeric forms were established. The stability of the phosphoramide bond under in vivo experimental conditions was checked. The methods of terminal phosphate chemical activation and terminal thiophosphate alkylation were applied to synthesize oligonucleotides equipped with hydrophobic, intercalating, alkylating, and photoactivatable groups. In the case of porphyrin-oligonucleotide conjugates, a series of new monofunctional porphyrin derivatives bearing a free aliphatic amino group was developed.

  10. A quasi-chemical nonrandom lattice fluid model: General derivation and application to pure fluids and mixtures

    Microsoft Academic Search

    Moon Sam Shin; Hwayong Kim

    2006-01-01

    A quasi-chemical nonrandom lattice fluid model without temperature dependence of the close packed volumes of a mer, segment numbers and energy parameters of pure systems is presented. The explicit nonrandom lattice fluid (NLF) model with quasi-chemical approach was capable of describing properties for complex systems, but this model had strong the temperature dependence of energy parameters and segment numbers of

  11. O-Succinyl-L-homoserine-based C4-chemical production: succinic acid, homoserine lactone, ?-butyrolactone, ?-butyrolactone derivatives, and 1,4-butanediol.

    PubMed

    Hong, Kuk-Ki; Kim, Jeong Hyun; Yoon, Jong Hyun; Park, Hye-Min; Choi, Su Jin; Song, Gyu Hyeon; Lee, Jea Chun; Yang, Young-Lyeol; Shin, Hyun Kwan; Kim, Ju Nam; Cho, Kyung Ho; Lee, Jung Ho

    2014-10-01

    There has been a significant global interest to produce bulk chemicals from renewable resources using engineered microorganisms. Large research programs have been launched by academia and industry towards this goal. Particularly, C4 chemicals such as succinic acid (SA) and 1,4-butanediol have been leading the path towards the commercialization of biobased technology with the effort of replacing chemical production. Here we present O-Succinyl-L-homoserine (SH) as a new, potentially important platform biochemical and demonstrate its central role as an intermediate in the production of SA, homoserine lactone (HSL), ?-butyrolactone (GBL) and its derivatives, and 1,4-butanediol (BDO). This technology encompasses (1) the genetic manipulation of Escherichia coli to produce SH with high productivity, (2) hydrolysis into SA and homoserine (HS) or homoserine lactone hydrochloride, and (3) chemical conversion of either HS or homoserine lactone HCL (HSL·HCl) into drop-in chemicals in polymer industry. This production strategy with environmental benefits is discussed in the perspective of targeting of fermented product and a process direction compared to petroleum-based chemical conversion, which may reduce the overall manufacturing cost. PMID:25155257

  12. Neurochemical analysis of amino acids, polyamines and carboxylic acids: GC–MS quantitation of tBDMS derivatives using ammonia positive chemical ionization

    Microsoft Academic Search

    Paul L. Wood; M. Amin Khan; Joseph R. Moskal

    2006-01-01

    The GC–MS quantitation of a large number of neurochemicals utilizing a single derivatization step is not common but is provided by the reagent N-(tert-butyldimethylsilyl)-N-methyltrifluro-acetamide (MTBSTFA). Previous workers have utilized this derivative for GC–MS analyses of amino acids, carboxylic acids and urea with electron impact (EI) and with positive chemical ionization (PCI; methane as reagent gas). However, these conditions yield significant

  13. Efficient, chemical-catalytic approach to the production of 3-hydroxypropanoic acid by oxidation of biomass-derived levulinic acid with hydrogen peroxide.

    PubMed

    Wu, Linglin; Dutta, Saikat; Mascal, Mark

    2015-04-13

    3-Hydroxypropanoic acid (HPA), a precursor to acrylic acid, can be produced in high yield by oxidation of the biomass-derived platform chemical levulinic acid. While treatment of levulinic acid with H2 O2 under acidic conditions gives predominantly succinic acid, a remarkable reversal of selectivity is observed under basic conditions, leading either directly to HPA or, under modified conditions, initially to 3-(hydroperoxy)propanoic acid, which can be quantitatively hydrogenated to HPA. PMID:25736835

  14. Chemical Modification of the ?-Glucocerebrosidase Inhibitor N-Octyl-?-valienamine: Synthesis and Biological Evaluation of 4-Epimeric and 4- O-(?- d-Galactopyranosyl) Derivatives

    Microsoft Academic Search

    Seiichiro Ogawa; Yuko Kobayashi Matsunaga; Yoshiyuki Suzuki

    2002-01-01

    N-Octyl-?-valienemine (1), a potent ?-glucocerebrosidase inhibitor, was chemically transformed into two biologically interesting compounds: the 4-epimer 2, ?-galacto-type N-octyl-valienamine, and the 4-O-(?-d-galactopyranosyl) derivative 3, a carba-lactosylceramide analogue. The former, interestingly, could be demonstrated to act as a very effective inhibitor (IC50=0.3 ?M) of human ?-galactosidase. The latter exhibited moderate inhibitory activity (IC50=20 ?M) against ?-glucocerebrosidase (mouse liver).

  15. Synthesis and physico-chemical and biological studies on ruthenium (III) complexes with Schiff bases derived from aminocarboxylic acids

    Microsoft Academic Search

    Vinod K. Sharma; Om P. Pandey; Soumitra K. Sengupta

    1987-01-01

    Summary Ruthenium(III) complexes of types [Ru(L)3], [Ru(L')Cl(H2O)2], [Ru(L?)Cl2]n, [Ru(L?)Cl(H2O)]n(LH =Schiff bases derived from anthranilic acid and benzaldehyde, acetophenone, vanillin, cinnamaldehyde orm-hydroxyacetophenone; L'H2=Schiff bases derived from anthranilic acid and salicylaldehyde oro-hydroxyacetophenone; L?H=Schiff bases derived fromp-aminobenzoic acid and benzaldehyde, acetophenone, vanillin, cinnamaldehyde orm-hydroxyacetophenone; L?H2=Schiff bases derived fromp-aminobenzoic acid and salicylaldehyde oro-hydroxyacetophenone) have been synthesized and characterized on the basis of elemental analyses,

  16. Reconstitution of anti-allergic activities of PG102 derived from Actinidia arguta by combining synthetic chemical compounds.

    PubMed

    Kim, Donghyun; Choi, Jinyong; Kim, Mi-Jeong; Kim, Seon Hee; Cho, Sang Heon; Kim, Sunyoung

    2013-06-01

    PG102, a water-soluble extract from an edible fruit, Actinidia arguta, has previously been shown to control various factors involved in allergy pathogenesis. It was investigated whether the original activities of PG102 could be reconstituted by mixing chemical compounds present in PG102. Six compounds present in PG102 were, individually or in the form of mixtures, tested for their effects on the expression of various Th2 cytokines and inflammatory mediators in the cell-based assay. Each chemical inhibited IL-4 expression to varying degrees. The chemical compounds were combined at a ratio present in PG102, resulting in two formulations, CQMIIH and CQM, consisting of all or the first three of the following chemicals, citric, quinic, and malic acids, myo-inositol, isoquercitrin, and 5-hydroxymethyl-2-furaldehyde. The mixtures reconstituted original activities of PG102 to a significant level. In the murine asthma model, CQM ameliorated asthmatic symptoms and significantly decreased the level of IgE and IL-5. The decreased phosphorylation of ERK1/2 was observed in cells and mice treated with PG102 and the mixtures. Our data indicated that the substantial portion of PG102's anti-allergic activities could be reconstituted, in vitro and in vivo, by mixing six chemical compounds, suggesting the possibility of developing a new type of anti-allergic agent. This approach may be useful for developing chemically defined functional products from complex botanical extracts. PMID:23918875

  17. Real-time continuous characterization of secondary organic aerosol derived from isoprene epoxydiols in downtown Atlanta, Georgia, using the Aerodyne Aerosol Chemical Speciation Monitor.

    PubMed

    Budisulistiorini, Sri Hapsari; Canagaratna, Manjula R; Croteau, Philip L; Marth, Wendy J; Baumann, Karsten; Edgerton, Eric S; Shaw, Stephanie L; Knipping, Eladio M; Worsnop, Douglas R; Jayne, John T; Gold, Avram; Surratt, Jason D

    2013-06-01

    Real-time continuous chemical measurements of fine aerosol were made using an Aerodyne Aerosol Chemical Speciation Monitor (ACSM) during summer and fall 2011 in downtown Atlanta, Georgia. Organic mass spectra measured by the ACSM were analyzed by positive matrix factorization (PMF), yielding three conventional factors: hydrocarbon-like organic aerosol (HOA), semivolatile oxygenated organic aerosol (SV-OOA), and low-volatility oxygenated organic aerosol (LV-OOA). An additional OOA factor that contributed to 33 ± 10% of the organic mass was resolved in summer. This factor had a mass spectrum that strongly correlated (r(2) = 0.74) to that obtained from laboratory-generated secondary organic aerosol (SOA) derived from synthetic isoprene epoxydiols (IEPOX). Time series of this additional factor is also well correlated (r(2) = 0.59) with IEPOX-derived SOA tracers from filters collected in Atlanta but less correlated (r(2) < 0.3) with a methacrylic acid epoxide (MAE)-derived SOA tracer, ?-pinene SOA tracers, and a biomass burning tracer (i.e., levoglucosan), and primary emissions. Our analyses suggest IEPOX as the source of this additional factor, which has some correlation with aerosol acidity (r(2) = 0.3), measured as H(+) (nmol m(-3)), and sulfate mass loading (r(2) = 0.48), consistent with prior work showing that these two parameters promote heterogeneous chemistry of IEPOX to form SOA. PMID:23638946

  18. Carcinogenicity predictions for a group of 30 chemicals undergoing rodent cancer bioassays based on rules derived from subchronic organ toxicities.

    PubMed Central

    Lee, Y; Buchanan, B G; Rosenkranz, H S

    1996-01-01

    Rodent carcinogenicities for a group of 30 chemicals which form the subject of the Second NIEHS Predictive-Toxicology Evaluation Experiment are predicted based on their subchronic organ toxicities. Predictions are made by rules learned by the rule learning (RL) induction program. PMID:8933055

  19. INFLUENCE OF DECOMPOSITION ON CHEMICAL PROPERTIES OF PLANT-AND MANURE-DERIVED DISSOLVED ORGANIC MATTER AND SORPTION TO GOETHITE

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sorption of dissolved organic matter (DOM) plays an important role in maintaining the fertility and quality of soils in agricultural ecosystems. Few studies have examined the effects of decomposition on DOM sorption and chemical characteristics. This study investigated the sorption to goethite of ...

  20. Identification of volatile/semivolatile products derived from chemical remediation of cis-1,3-dichloropropene by thiosulfate

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The prevalent use of soil fumigants resulted in air pollution in some agricultural regions. Our previous research showed that application of thiosulfate fertilizers at the soil surface may offer an effective and economical approach to reduce the emission of halogenated fumigants via a chemical remed...

  1. VITEXIN DERIVATIVES AS CHEMICAL MARKERS IN THE DIFFERENTIATION OF THE CLOSELY RELATED SPECIES PASSIFLORA ALATA CURTIS. AND PASSIFLORA QUADRANGULARIS LINN

    Microsoft Academic Search

    Geison M. Costa; Andressa C. Gazola; Fernanda A. Madóglio; Silvana M. Zucolotto; Flávio H. Reginatto; Leonardo Castellanos; Freddy A. Ramos; Carmenza Duque; Eloir P. Schenkel

    2012-01-01

    The species of Passiflora are widely used in folk medicine as mild sedatives and tranquilizers. P. alata and P. quadrangularis are distributed throughout South America, with widespread occurrence in Brazil and Colombia. Due to the difficulty in making a botanical distinction between these species, especially in the absence of flowers and fruits, the use of chemical markers for these plants

  2. Design, synthesis, characterization, quantum-chemical calculations and anti-inflammatory activity of novel series of thiophene derivatives

    NASA Astrophysics Data System (ADS)

    Helal, M. H.; Salem, M. A.; Gouda, M. A.; Ahmed, N. S.; El-Sherif, A. A.

    2015-08-01

    Interaction of 1-(4-morpholinophenyl)ethanone 1 with either malononitrile or ethyl cyanoacetate 2 afforded Knoevenagel-Cope product 3. In subsequent treatment of 3 with sulfur, the 2-aminothiophene derivatives (4a, 4b) are formed under basic conditions. The solvent-free reaction of thiophene derivative 4a with ethyl cyanoacetate afforded thieno[2,3-d][1,3]oxazine derivative 6. The base catalyzed condensation of 2-aminothiophene derivative (4a) with ethyl cyanoacetate afforded N-(thieno-2-yl) cyanoacetamide derivative 7. The latter was used to synthesize different heterocyclic derivatives comprising, pyridine and coumarin rings. Also, several substituted thieno[2,3-d]pyrimidines have been prepared from reaction of 2-aminothiophene-3-carbonitrile 4b with some electrophilic reagents. The structure of the newly compounds were confirmed on the basis of elemental analysis and spectral data. The molecular modeling of the synthesized compounds has been drawn and their molecular parameters were calculated. Also, valuable information is obtained from calculation of the molecular parameters including electronegativity, net dipole moment of the compounds, total energy, electronic energy, binding energy, HOMO and LUMO energy. Evaluation of anti-inflammatory activity of the tested compounds was performed in albino rats by producing carrageenan induced paw oedema and measuring the zone of inflammation at different time intervals i.e. 1, 2, 3 and 4 h after carrageenan injection. Results indicated that most of the tested compounds showed moderate to good activity comparable to indomethacin. Also, compound 16 with additional morpholine ring beside the thiophene ring inhibits carrageenan induced paw oedema more than the standard indomethacin drug at all the time scales studied. Thus, compound 16 is considered as a promising compound for further modification to obtain clinically useful anti-inflammatory agent.

  3. Design, synthesis, characterization, quantum-chemical calculations and anti-inflammatory activity of novel series of thiophene derivatives.

    PubMed

    Helal, M H; Salem, M A; Gouda, M A; Ahmed, N S; El-Sherif, A A

    2015-08-01

    Interaction of 1-(4-morpholinophenyl)ethanone 1 with either malononitrile or ethyl cyanoacetate 2 afforded Knoevenagel-Cope product 3. In subsequent treatment of 3 with sulfur, the 2-aminothiophene derivatives (4a, 4b) are formed under basic conditions. The solvent-free reaction of thiophene derivative 4a with ethyl cyanoacetate afforded thieno[2,3-d][1,3]oxazine derivative 6. The base catalyzed condensation of 2-aminothiophene derivative (4a) with ethyl cyanoacetate afforded N-(thieno-2-yl) cyanoacetamide derivative 7. The latter was used to synthesize different heterocyclic derivatives comprising, pyridine and coumarin rings. Also, several substituted thieno[2,3-d]pyrimidines have been prepared from reaction of 2-aminothiophene-3-carbonitrile 4b with some electrophilic reagents. The structure of the newly compounds were confirmed on the basis of elemental analysis and spectral data. The molecular modeling of the synthesized compounds has been drawn and their molecular parameters were calculated. Also, valuable information is obtained from calculation of the molecular parameters including electronegativity, net dipole moment of the compounds, total energy, electronic energy, binding energy, HOMO and LUMO energy. Evaluation of anti-inflammatory activity of the tested compounds was performed in albino rats by producing carrageenan induced paw oedema and measuring the zone of inflammation at different time intervals i.e. 1, 2, 3 and 4h after carrageenan injection. Results indicated that most of the tested compounds showed moderate to good activity comparable to indomethacin. Also, compound 16 with additional morpholine ring beside the thiophene ring inhibits carrageenan induced paw oedema more than the standard indomethacin drug at all the time scales studied. Thus, compound 16 is considered as a promising compound for further modification to obtain clinically useful anti-inflammatory agent. PMID:25827768

  4. Comparison of tropical and temperate freshwater animal species' acute sensitivities to chemicals: implications for deriving safe extrapolation factors

    Microsoft Academic Search

    Kevin WH Kwok; Kenneth MY Leung; Gilbert SG Lui; Vincent KH Chu; Paul KS Lam; David Morritt; Lorraine Maltby; Theo CM Brock; Brink van den P. J; Michael St J Warne; Mark Crane

    2007-01-01

    Toxicity data for tropical species are often lacking for ecological risk assessment. Consequently, tropical and subtropical countries use water quality criteria (WQC) derived from temperate species (e.g., United States, Canada, or Europe) to assess ecological risks in their aquatic systems, leaving an unknown margin of uncertainty. To address this issue, we use species sensitivity distributions of freshwater animal species to

  5. Chemically-responsive complexation of a diquaternary salt with bis(m-phenylene)-32-crown-10 derivatives and host substituent effect on complexation geometry.

    PubMed

    Yan, Xuzhou; Li, Zhengtao; Wei, Peifa; Huang, Feihe

    2013-02-01

    A chemically responsive diquaternary salt with ?-extended surface was made. The host-guest complexation with chemo-responsiveness between three bis(m-phenylene)-32-crown-10 (BMP32C10) derivatives and this diquaternary salt guest was studied through the sequential addition of basic and acidic reagents (diethylamine and trifluoroacetic acid, respectively). Furthermore, the host-substituent effect on the complexation geometries of these three host-guest complexes, from taco to taco-type threaded to threaded structures by changing the substituent on BMP32C10 as shown by crystal structures, was also addressed. PMID:23320925

  6. Chemical modification of the beta-glucocerebrosidase inhibitor N-octyl-beta-valienamine: synthesis and biological evaluation of 4-epimeric and 4-O-(beta-D-galactopyranosyl) derivatives.

    PubMed

    Ogawa, Seiichiro; Matsunaga, Yuko Kobayashi; Suzuki, Yoshiyuki

    2002-06-01

    N-Octyl-beta-valienemine (1), a potent beta-glucocerebrosidase inhibitor, was chemically transformed into two biologically interesting compounds: the 4-epimer, beta-galacto-type N-octyl-valienamine, and the 4-O-(beta-D-galactopyranosyl) derivative, a carba-lactosylceramide analogue. The former, interestingly, could be demonstrated to act as a very effective inhibitor (IC(50)=0.3 microM) of human beta-galactosidase. The latter exhibited moderate inhibitory activity (IC(50)=20 microM) against beta-glucocerebrosidase (mouse liver). PMID:11937356

  7. 40 CFR 721.1820 - Bisphenol derivative.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...2011-07-01 2011-07-01 false Bisphenol derivative. 721.1820 Section 721...Chemical Substances § 721.1820 Bisphenol derivative. (a) Chemical substance...chemical substance identified generically as bisphenol derivative (PMN No....

  8. 40 CFR 721.1820 - Bisphenol derivative.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...2010-07-01 2010-07-01 false Bisphenol derivative. 721.1820 Section 721...Chemical Substances § 721.1820 Bisphenol derivative. (a) Chemical substance...chemical substance identified generically as bisphenol derivative (PMN No....

  9. High-resolution X-ray spectroscopic and quantum-chemical study of electron interactions in fullerene derivatives.

    NASA Astrophysics Data System (ADS)

    Okotrub, Alexander; Bulusheva, Lyubov; Tománek, David

    1998-03-01

    Fluorescent high-resolution spectra of the fullerenes C_60, C_70, and their compounds with various types of chemical bonding were measured using the X-ray spectrometer ``Stearat''. The CK_? spectra of C_60F_24, C_60H_36, K_xC_60, Pd_xC_60 were obtained with resolution ?0.3 eV. The interpretation of the experimental data was performed using the quantum-chemical PM3 computational method. Several isomers were considered in the calculations for C_60F_24 and C_60H_36. The isomers that showed the best agreement between theoretical spectra and experimental data were selected for further study of electron interactions. The correlation diagrams for the interactions between the MO's of C_60 and the AO's of hydrogen and fluorine have been obtained. The main effect of fullerene intercalation by potassium is a maximum at short wavelengths which is clearly observed in the X-ray spectra. X-ray emission spectra and quantum-chemical results indicate that the interaction between C_60 and adsorbed palladium atoms has a donor-acceptor nature.

  10. A new cytotoxic prenylated dihydrobenzofuran derivative and other chemical constituents from the rhizomes of Atractylodes lancea DC.

    PubMed

    Duan, Jin-ao; Wang, Liuying; Qian, Shihui; Su, Shulan; Tang, Yuping

    2008-08-01

    A new prenylated dihydrobenzofuran derivative (1), was isolated from the rhizomes of Atractylodes lancea DC (Asteraceae), along with ten known compounds, including atractylenolide II (2), phi-taraxasteryl acetate (3), taraxerol acetate (4), beta-sitosterol (5), stigmasterol (6), beta-eudesmol (7), atractylenolide III (8), atractylenolide IV (9), daucosterol (10), and stigmasterol 3-O-beta-D-glucopyranoside (11). The structure of the new compound (1) was elucidated as trans-2-hydroxyisoxypropyl-3-hydroxy-7-isopentene-2,3-dihydrobenzofuran-5-carboxylic acid by the combination of 1D, 2D NMR analysis and mass spectrometry, and it was the first reported 2,3-dihydrobenzofuran derivative having a carboxyl residue at C-5 and an isopentene moiety at C-7 contemporaneously. In addition, compound 1 exhibited significant cytotoxicity against cancer cell lines HCT-116 and MKN-45. PMID:18787781

  11. Novel 1,3,4-thiadiazolium-2-phenylamine chlorides derived from natural piperine as trypanocidal agents: Chemical and biological studies

    Microsoft Academic Search

    Welisson da Silva Ferreira; Leonardo Freire-de-Lima; Víctor Barbosa Saraiva; Frederico Alisson-Silva; Lucia Mendonça-Previato; José Osvaldo Previato; Aurea Echevarria; Marco Edilson Freire de Lima

    2008-01-01

    We herein describe the synthesis and characterization of nine new 1,3,4-thiadiazolium-2-phenylamine chlorides derived from natural piperine. We evaluate their toxic effects against the different evolutive forms of Trypanosoma cruzi, and the host cell (murine macrophages). The results obtained show that mesoionic hydrochloride MI possesses the best activity profile. Compound MI may be a prototype for use in the development of

  12. Studies on nitrotyrosine-82 and aminotyrosine-82 derivatives of adrenodoxin. Effects of chemical modification on the complex formation with adrenodoxin reductase.

    PubMed

    Taniguchi, T; Kimura, T

    1976-06-29

    The coordination structure of the iron-sulfur center of the nitrotyrosine and the aminotyrosine derivates of bovine adrenodoxin was investigated by electron paramagnetic resonance spectroscopy. The reduced form of both modified samples exhibited signals identical with those for the native protein at g= 1.94 and g=2.01. From these results together with optical absorption and chemical analyses, it was concluded that the coordination structure of the iron-sulfur chromophore for both the derivatives was identical with the binuclear tetrahedral structure of native adrenodoxin. The configuration of the iron-binding area in nitro- and amino-adrenodoxin was studied by ovserving the circular dichroism spectra between 350 and 600 nm. The maxima for the nitro or amino derivatives were all identical with those for the native protein but different in the magnitude of their molar ellipticity. The molar ellipticities at 440 nm were 45.8 X 10(3), 14.5 X 10(3), and 9.5 X 10(6) deg cm2 per mol of iron for native adrenodoxin, nitro or amino derivative, respectively. These results suggest that the chemical modification of the tyrosine residue causes a conformational change in the iron-binding area. We have previously reported that the enzymatic activities of these reconstituted nitro and amino derivatives toware cytochrome c reduction in the presence of adrenodoxin reductase and reduced nicotinamide adenine dinucleotide phosphate were 19 and 7% of native adrenodoxin, respectively. The cytochrome c reductase activities of nitro- and aminoadrenodixin were drastically affected by the ionic strength of the assay medium, as found in native adrenodoxin. Fluorometric titration of the reductase with aminoadrenodoxin revealed that aminoadrenodoxin forms a 1:1 molar complex with the reductase. These results suggest that both the nitro and amino derivatives form a complex with the reductase. The dissociation constants of nitro- and aminoadrenodoxin for the reductase were 6.1 X 10(-7)M and 3.3 X 10(-7) M at mu = 0.04 and 1.9 X 10(-6) M and 2.0 X 10(-6) M at mu = 0.20, respectively. Comparison of these values with those of native adrenodoxin (approximately 10(-9) M at mu = 0.04 and 2.2 X 10(-7) M at mu = 0.20) suggests that an increase in the dissociation constant for the reductase is responsible for the decreased electron transferring activity of the modified adrenodoxins. PMID:181049

  13. Gas chromatography-electron ionization and chemical ionization mass spectrometric analysis of urinary phenmetrazine after derivatization with 4-carbethoxyhexafluorobutyryl chloride--a new derivative.

    PubMed

    Dasgupta, A; Hart, A; Humphrey, P; Blackwell, W

    1998-05-01

    Phenmetrazine is a central nervous system stimulant currently used as an anorectic agent. The drug is abused and is reported to cause death from overdose. We describe a new derivatization method for phenmetrazine using 4-carbethoxyhexafluorobutyryl chloride. Quantitation of urinary phenmetrazine can be easily achieved by using N-ethyl amphetamine as an internal standard. The electron ionization mass spectrum of 4-carbethoxyhexafluorobutyryl derivative of phenmetrazine showed a molecular ion at m/z 427 and a base peak at m/z 70. In the methane chemical ionization mass spectrum, the base peak was observed at m/z 428 (protonated molecular ion). In the electron ionization mass spectrum of 4-carbethoxyhexafluorobutyryl derivative of the internal standard, N-ethyl amphetamine we did not observe a molecular ion. However, in the chemical ionization mass spectrum, the protonated molecular ion at m/z 414 was the base peak. The retention time of derivatized phenmetrazine (8.4 min) was substantially longer than the retention time of the underivatized molecule. Moreover, underivatized phenmetrazine showed poor peak shape (substantial tailing) while derivatized phenmetrazine had excellent chromatographic properties. The within-run and between-run precisions of the assay were 2.6% and 3.1% respectively at a urinary phenmetrazine concentration of 10 micrograms/mL. The assay was linear for urinary phenmetrazine concentration of 1 to 100 micrograms/mL with a detection limit of 0.2 microgram/mL. PMID:9608702

  14. Influence of decomposition on chemical properties of plant- and manure-derived dissolved organic matter and sorption to goethite.

    PubMed

    Hunt, James F; Ohno, Tsutomu; He, Zhongqi; Honeycutt, C Wayne; Dail, D Bryan

    2007-01-01

    Sorption of dissolved organic matter (DOM) plays an important role in maintaining the fertility and quality of soils in agricultural ecosystems. Few studies have examined the effects of decomposition on DOM sorption and chemical characteristics. This study investigated the sorption to goethite (alpha-FeOOH) of fresh and decomposed hydrophilic (HPL) and hydrophobic (HPB) DOM fractions extracted from the shoots and roots of crimson clover (Trifolium incarnatum L.), corn (Zea mays L.), soybean [Glycine max (L.) Merr.], hairy vetch (Vicia villosa L.), and dairy and poultry manures. Sorption was positively related to apparent molecular weight (MWAP), aromaticity as measured by absorptivity at 280 nm, and phenolic acid content. A 10-d laboratory microbial decomposition of the source organic matter generally increased the sorption of the extracted DOM onto goethite. The decomposition effect on sorption was greater for the HPL fractions than for the HPB fractions. There was a decrease in the MWAP values of the DOM samples following sorption to goethite. In many cases the reduction in MWAP was large, indicating a strong preference by goethite for the higher MWAP DOM fractions. The results of this laboratory-based research demonstrate that microbial processes affect the chemical characteristics of DOM which may affect the distribution of soil organic C pools. PMID:17215221

  15. Biogenic Synthesis, Purification, and Chemical Characterization of Anti-inflammatory Resolvins Derived from Docosapentaenoic Acid (DPAn-6)

    PubMed Central

    Dangi, Bindi; Obeng, Marcus; Nauroth, Julie M.; Teymourlouei, Mah; Needham, Micah; Raman, Krishna; Arterburn, Linda M.

    2009-01-01

    Enzymatically oxygenated derivatives of the ?-3 fatty acids cis-4,7,10,13,16,19-docosahexaenoic acid (DHA) and cis-5,8,11,14,17-eicosapentaenoic acid, known as resolvins, have potent inflammation resolution activity (Serhan, C. N., Clish, C. B., Brannon, J., Colgan, S. P., Chiang, N., and Gronert, K. (2000) J. Exp. Med. 192, 1197–1204; Hong, S., Gronert, K., Devchand, P. R., Moussignac, R., and Serhan, C. N. (2003) J. Biol. Chem. 278, 14677–14687). Our objective was to determine whether similar derivatives are enzymatically synthesized from other C-22 fatty acids and whether these molecules possess inflammation resolution properties. The reaction of DHA, DPAn-3, and DPAn-6 with 5-, 12-, and 15-lipoxygenases produced oxylipins, which were identified and characterized by liquid chromatography coupled with tandem mass-spectrometry. DPAn-6 and DPAn-3 proved to be good substrates for 15-lipoxygenase. 15-Lipoxygenase proved to be the most efficient enzyme of the three tested for conversion of long chain polyunsaturated fatty acids to corresponding oxylipins. Since DPAn-6 is a major component of Martek DHA-S™ oil, we focused our attention on reaction products obtained from the DPAn-6 and 15-lipoxygenase reaction. (17S)-hydroxy-DPAn-6 and (10,17S)-dihydroxy-DPAn-6 were the main products of this reaction. These compounds were purified by preparatory high performance liquid chromatography techniques and further characterized by NMR, UV spectrophotometry, and tandem mass spectrometry. We tested both compounds in two animal models of acute inflammation and demonstrated that both compounds are potent anti-inflammatory agents that are active on local intravenous as well as oral administration. These oxygenated DPAn-6 compounds can thus be categorized as a new class of DPAn-6-derived resolvins. PMID:19324874

  16. Structure and physico-chemical properties of hexadentate Schiff base zinc complexes derived from salicylaldehydes and triethylenetetramine*1

    NASA Astrophysics Data System (ADS)

    Chantarasiri, Nuanphun; Ruangpornvisuti, Vithaya; Muangsin, Nongnuj; Detsen, Hussadee; Mananunsap, Thussanee; Batiya, Chureephon; Chaichit, Narongsak

    2004-09-01

    Two hexadentate Schiff base zinc complexes, ZnSal 2trien and ZnVan 2trien, where Sal=salicylaldehyde, Van= o-vanillin, and trien=triethylenetetramine, have been synthesized by the reaction between salicylaldehydes, triethylenetetramine and zinc acetate. The structure of ZnSal 2trien and ZnVan 2trien were determined by single crystal X-ray crystallography. It was found that both ZnSal 2trien and ZnVan 2trien have a bent-shaped structure. Properties of the complexes were examined using differential scanning calorimetry, polarized optical microscopy and small angle X-ray scattering. Protonation constants of the ligands Sal 2trien and Van 2trien and stability constants of their zinc complexes were determined by potentiometric titration. Binding energies of ZnSal 2trien and ZnVan 2trien complexes were obtained by quantum chemical calculations.

  17. Chemical and morphological changes in hydrochars derived from microcrystalline cellulose and investigated by chromatographic, spectroscopic and adsorption techniques.

    PubMed

    Diakité, Mamadou; Paul, Andrea; Jäger, Christian; Pielert, Judith; Mumme, Jan

    2013-12-01

    Hydrothermal carbonization (HTC) can be used for converting the biomass into a carbon-rich material, whose application as a fuel requires higher heating value, whereas soil amendment needs stable carbon. This work was focused on the characterization of hydrochars derived from microcrystalline cellulose. The chars were investigated using elemental analysis, Brunauer-Emmett-Teller technique, nuclear magnetic resonance spectroscopy, Raman, Fourier transform infrared, and electron spin resonance spectroscopy. Severity in temperature between 230 and 270°C with reaction times between 2 and 10 h only affect the carbon content moderately. The results show that aromatization of HTC chars correlates well with temperature, which was further supported by the increase of organic radicals with decreasing g values at higher temperatures. Based on these results, the energetic use of chars favors mild HTC (T<230°C and t?6 h), while the soil amendement favors serve conditions (T?230°C, and t>6 h). PMID:24157681

  18. Coumarins from the Herb Cnidium monnieri and Chemically Modified Derivatives as Antifoulants against Balanus albicostatus and Bugula neritina Larvae

    PubMed Central

    Wang, Zhan-Chang; Feng, Dan-Qing; Ke, Cai-Huan

    2013-01-01

    In the search for new environmental friendly antifouling (AF) agents, four coumarins were isolated from the herbal plant Cnidium monnieri, known as osthole (1), imperatorin (2), isopimpinellin (3) and auraptenol (4). Furthermore, five coumarin derivatives, namely 8-epoxypentylcoumarin (5), meranzin hydrate (6), 2?-deoxymetranzin hydrate (7), 8-methylbutenalcoumarin (8), and micromarin-F (9) were synthesized from osthole. Compounds 1, 2, 4, 7 showed high inhibitory activities against larval settlement of Balanus albicostatus with EC50 values of 4.64, 3.39, 3.38, 4.67 ?g mL?1. Compound 8 could significantly inhibit larval settlement of Bugula neritina with an EC50 value of 3.87 ?g mL?1. The impact of functional groups on anti-larval settlement activities suggested that the groups on C-5? and C-2?/C-3? of isoamylene chian could affect the AF activities. PMID:23303279

  19. Optical absorption measurements and quantum-chemical simulations of optical properties of novel fluoro derivatives of pyrazoloquinoline

    NASA Astrophysics Data System (ADS)

    Brik, M. G.; Kuznik, W.; Gondek, E.; Kityk, I. V.; Uchacz, T.; Szlachcic, P.; Jarosz, B.; Plucinski, K. J.

    2010-05-01

    The results of experimental research and quantum-chemical simulations of the absorption spectra of 1-(4-fluorophenyl)-3,4-diphenyl, 3-(4-fluorophenyl)-1,4-diphenyl, and 4-(4-fluorophenyl)-1,3-diphenyl-pyrazolo[3,4- b] quinoline are presented. Although the fluorine atom is located on different phenyl rings in these molecules, the absorption spectra do not differ significantly. Semi-empirical AM1, PM3 and RM1 methods, as well as ab initio ADF code-based calculations were used to optimize geometry, calculate the infrared and visible spectra of the afore mentioned compounds and analyze the molecular orbitals schemes. The results of calculations are in good agreement with the experimental data. It was also demonstrated that the positions of the fluorescence maxima depend significantly on the solvent (contrary to the absorption spectra), in which the molecules are embedded, which allows for manipulating with fluorescence properties of the synthesized molecules by changing the solvent.

  20. Influence of stoichiometry on the optical and electrical properties of chemical vapor deposition derived MoS2.

    PubMed

    Kim, In Soo; Sangwan, Vinod K; Jariwala, Deep; Wood, Joshua D; Park, Spencer; Chen, Kan-Sheng; Shi, Fengyuan; Ruiz-Zepeda, Francisco; Ponce, Arturo; Jose-Yacaman, Miguel; Dravid, Vinayak P; Marks, Tobin J; Hersam, Mark C; Lauhon, Lincoln J

    2014-10-28

    Ultrathin transition metal dichalcogenides (TMDCs) of Mo and W show great potential for digital electronics and optoelectronic applications. Whereas early studies were limited to mechanically exfoliated flakes, the large-area synthesis of 2D TMDCs has now been realized by chemical vapor deposition (CVD) based on a sulfurization reaction. The optoelectronic properties of CVD grown monolayer MoS2 have been intensively investigated, but the influence of stoichiometry on the electrical and optical properties has been largely overlooked. Here we systematically vary the stoichiometry of monolayer MoS2 during CVD via controlled sulfurization and investigate the associated changes in photoluminescence and electrical properties. X-ray photoelectron spectroscopy is employed to measure relative variations in stoichiometry and the persistence of MoOx species. As MoS2-? is reduced (increasing ?), the field-effect mobility of monolayer transistors increases while the photoluminescence yield becomes nonuniform. Devices fabricated from monolayers with the lowest sulfur content have negligible hysteresis and a threshold voltage of ? 0 V. We conclude that the electrical and optical properties of monolayer MoS2 crystals can be tuned via stoichiometry engineering to meet the requirements of various applications. PMID:25223821

  1. Synthesis, physico-chemical properties and biological analysis of newly obtained copper(II) complexes with pyrazole derivatives.

    PubMed

    Grazul, Magdalena; Besic-Gyenge, Emina; Maake, Caroline; Ciolkowski, Michal; Czyz, Malgorzata; Sigel, Roland K O; Budzisz, Elzbieta

    2014-06-01

    Three new copper(II) complexes containing two different pyrazole bound ligands (1, 2) have been synthesized and characterized by IR, LSI-MS (liquid secondary ion mass spectrometry) and elemental analysis. (1)H NMR spectra of the organic ligands have been recorded. We describe the influence of these complexes on particular cancer cell lines and DNA structure by MTT-assay [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide], APA (acid phosphatase activity)-assay or CD-spectroscopy and agarose gel electrophoresis methods, together with their physico-chemical properties such as lipophilicity and stability in aqueous solution. The cytotoxic effect on HUVEC (endothelial cells) for the most active complex 4 has been also investigated. Moreover, the ability of these complexes to induce apoptosis in cancer cells has been assessed by using fluorescence microscopy. Our results indicate that dichloridobis{1-[amino(thioxo)methyl]-5-hydroxy-3-phenyl-1H-pyrazole-?N2}copper(II) is the most potent complex among the tested complexes. PMID:24662465

  2. UV-vis spectroscopy and semiempirical quantum chemical studies on methyl derivatives of annulated analogues of azafluoranthene and azulene dyes.

    PubMed

    Danel, K S; Gasiorski, P; Matusiewicz, M; Ca?us, S; Uchacz, T; Kityk, A V

    2010-09-15

    Paper reports the measured optical absorption and fluorescence spectra of 4-(2-chlorophenyl)-7-methyl-1,3-diphenyl-1H-pyrazolo[3,4-b]quinoline (MCPDPPQ), as well as 6-methyl-1,3-diphenyl-3H-indeno[1,2,3-de]pyrazolo[3,4-b]quinoline (MDPIPQ) and 9-methyl-6-phenyl-6H-5,6,7-triazadibenzo[f,h]naphtho[3,2,1-cd]azulene (MPTNA) representing cyclized five- or seven-membered regioisomeric products of MCPDPPQ, respectively. The spectra has been recorded in solvents of different polarity and compared with the results of quantum chemical calculations performed by means of the semiempirical method PM3 in combination with molecular dynamics (MD) simulations. Cyclization of MCPDPPQ into MDPIPQ or MPTNA is accompanied by a significant red shift of the first optical absorption and fluorescence bands. While the solvent polarity rises all the dyes exhibit the blue shift of the first absorption band and the red shift of the fluorescence band. These trends have been reproduced within the semiempirical calculations in combination with the Lippert-Mataga dielectric polarization model and explained by specific orientations of the dipole moments in the ground and excited states. All dyes may be considered as candidates for the luminescent or electroluminescent applications. Depending on solvent polarity they emit light in the green-yellow range of the visible spectra. PMID:20510645

  3. Physico-chemical characterization of polymeric micelles loaded with platinum derivatives by capillary electrophoresis and related methods.

    PubMed

    Oukacine, Farid; Bernard, Stephane; Bobe, Iulian; Cottet, Hervé

    2014-12-28

    (1,2-diamino-cyclohexane)Platinum(II) ((DACH)Pt) loaded polymeric micelles of poly(ethylene glycol-b-sodium glutamate) (PEG-b-PGlu) are currently studied as a potential candidate to replace oxaliplatin in the treatment of cancers with the aim to reduce side effects like cumulative peripheral distal neurotoxicity and acute dysesthesias. As for all synthetic polymeric drug delivery systems, the characterization of the (co)polymer precursors and of the final drug delivery system (polymeric micelles) is crucial to control the repeatability of the different batches and to get correlation between physico-chemical structure and biological activity. In this work, the use of capillary electrophoresis (CE) and related methods for the characterization of (DACH)Pt-loaded polymeric micelles and their precursor (PEG-b-PGlu copolymer) has been investigated in detail. The separation and quantification of residual PGlu homopolymer in the PEG-b-PGlu sample were performed by free solution capillary zone electrophoresis mode. This mode brought also information on the PEG-b-PGlu copolymer composition and polydispersity. It also permitted to monitor the decomposition of polymeric micelles in the presence of NaCl at room temperature. Interactions between PEG-b-PGlu unimers, on one hand, and polymeric micelles or surfactants, on the other hand, were studied by using the Micellar Electrokinetic Chromatography and Frontal Analysis Capillary Electrophoresis modes. Finally, weight-average hydrodynamic radii of the loaded polymeric micelles and of the PEG-b-PGlu unimers were determined by Taylor Dispersion Analysis (an absolute size determination method that can be easily implemented on CE apparatus). PMID:25270114

  4. Physical and chemical characterization and comparison of solids, liquids, and oils derived from Estonian and Green River formation shales

    SciTech Connect

    Peterson, E.J.; Spall, W.D.

    1981-01-01

    Although only a single Estonian raw shale sample with an unknown history has been examined, physical and chemical characterization of this material has been accomplished. A comparison with a representative Green River formation raw shale has been made. Some of the findings are: (1) Elemental analysis indicates that the major elements, aluminum, magnesium, and sodium are deficient in Estonian shale compared to the Green River shale. The minor elements, barium and strontium, and the trace elements, arsenic, cobalt, rare earths, uranium, vanadium, and zinc are also deficient in the Estonian shale compared to the Green River shale. (2) Green River shales contain greater quantities of clay minerals (mainly illite) compared to the Estonian shale. (3) X-ray diffraction data suggests that ..cap alpha..-quartz concentration in the Estonian material is two to three times less than in typical Green River shales. (4) The suite of minerals in the Estonian spent shale suggests extreme processing conditions. (5) Scanning electron microscopy-electron microprobe analysis results indicate the intimate contact of the minerals on the micron level in the Green River shales. Mineral grains in the Estonian shale are dispersed throughout the organic material. (6) Aqueous leaching experiments indicate lead mobility from the Estonian spent materials result in concentrations that are undesirably high. (7) Phenolic compoundsare the most concentrated organic species present in the aqueous Estonian leachates. By comparison, carboxylic acids are the most concentrated species in the Green River leachates. (8) The Estonian raw shale sample has a Fischer assay of 93 barrels per ton, and the Green River an assay of 26 barrels per ton. (9) Organic solvent extraction of the raw shales with 15 different solvents show that approximately 60% of the kerogen in the Green River shale is extractable and only 3.8% of the Estonian shale is extracted under the same conditions.

  5. In vitro antibacterial activity of sphaeropsidins and chemical derivatives toward Xanthomonas oryzae pv. oryzae, the causal agent of rice bacterial blight.

    PubMed

    Evidente, Antonio; Venturi, Vittorio; Masi, Marco; Degrassi, Giuliano; Cimmino, Alessio; Maddau, Lucia; Andolfi, Anna

    2011-12-27

    Sphaeropsidin A, the main phytotoxin produced by Diplodia cupressi, as well as the two natural analogues sphaeropsidins B and C and 14 derivatives obtained by chemical modifications were assayed for antibacterial activity against Xanthomonas oryzae pv. oryzae, Pseudomonas fuscovaginae, and Burkholderia glumae, the causal agents of severe bacterial rice diseases. The results showed a strong and specific activity of sphaeropsidin A against X. oryzae pv. oryzae, while no activity was observed against the other two pathogens. The results of structure-activity relationship studies showed that structural features important to impart this antibacterial activity are the presence of the C-7 carbonyl group and the hemiketalic lactone functionality. The C-13 vinyl group, the double bond of ring C, and/or the tertiary C-9 hydroxy group, as well as the pimarane arrangement of the tricylic carbon skeleton, were also important for the antibacterial activity. These findings may be useful in designing novel compounds for practical applications in agriculture. PMID:22124378

  6. Soluble sulfur species extracted from coal by chemical leaching. [MS thesis; mineral and coal-derived pyrite; 114 references

    SciTech Connect

    Stephenson, M.D.

    1982-07-01

    The nature of the soluble sulfur-containing reaction products from the desulfurization of pyrite was studied. The rate of oxydesulfurization of the two varieties of pyrite was studied under the leaching conditions of the Ames process. Concentrations of soluble sulfur species were determined for oxydesulfurization using leach solutions of sodium carbonate, sodium bicarbonate, distilled water, and dilute sulfuric acid and for alkaline leaching without oxygen using sodium carbonate. Mineral grade pyrite was found to be much less reactive towards oxydesulfurization than coal-derived pyrite, although the mechanism of sulfur removal was apparently the same. The sulfur containing products of oxydesulfurization were found to be thiosulfate, sulfite, and sulfate for alkaline leach solutions, and elemental sulfur and sulfuric acid when neutral or acidic solutions were used. For the Ames process, thiosulfate was usually the major sulfur containing product, although oxidation to sulfite and sulfate was found to take place. Oxidation of thiosulfate did not occur with oxygen alone, but did occur in the presence of oxygen and partially reacted pyrite. Higher temperatures and higher oxygen partial pressures favored formation of sulfate at the expense of both thiosulfate and sulfite. With neutral and acidic leach solutions, sulfuric acid accounted for most of the sulfur, although measurable quantities of elemental sulfur were present.Higher oxygen partial pressures and higher temperatures favored the formation of sulfuric acid at the expense of elemental sulfur. Pyrite oxidized faster under alkaline conditions than under neutral or acidic conditions. Pyrite was also leached at high temperatures in a sodium carbonate solution in the absence of oxygen.

  7. Common host-derived chemicals increase catches of disease-transmitting mosquitoes and can improve early warning systems for Rift Valley fever virus.

    PubMed

    Tchouassi, David P; Sang, Rosemary; Sole, Catherine L; Bastos, Armanda D S; Teal, Peter E A; Borgemeister, Christian; Torto, Baldwyn

    2013-01-01

    Rift Valley fever (RVF), a mosquito-borne zoonosis, is a major public health and veterinary problem in sub-Saharan Africa. Surveillance to monitor mosquito populations during the inter-epidemic period (IEP) and viral activity in these vectors is critical to informing public health decisions for early warning and control of the disease. Using a combination of field bioassays, electrophysiological and chemical analyses we demonstrated that skin-derived aldehydes (heptanal, octanal, nonanal, decanal) common to RVF virus (RVFV) hosts including sheep, cow, donkey, goat and human serve as potent attractants for RVFV mosquito vectors. Furthermore, a blend formulated from the four aldehydes and combined with CO(2)-baited CDC trap without a light bulb doubled to tripled trap captures compared to control traps baited with CO(2) alone. Our results reveal that (a) because of the commonality of the host chemical signature required for attraction, the host-vector interaction appears to favor the mosquito vector allowing it to find and opportunistically feed on a wide range of mammalian hosts of the disease, and (b) the sensitivity, specificity and superiority of this trapping system offers the potential for its wider use in surveillance programs for RVFV mosquito vectors especially during the IEP. PMID:23326620

  8. Computational and Experimental Assessment of Benzene Cation Chemistry for the Measurement of Marine Derived Biogenic Volatile Organic Compounds with Chemical Ionization Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Zoerb, M.; Kim, M.; Zimmermann, K.; Bertram, T. H.

    2013-12-01

    Chemical ionization mass spectrometry (CIMS) is a highly selective and sensitive technique for the measurement of trace gases in the atmosphere. However, competing side reactions and dependence on relative humidity (RH) can make the transition from the laboratory to the field challenging. Effective implementation of chemical ionization requires a thorough knowledge of the elementary steps leading to ionization of the analyte. We have recently investigated benzene cations for the detection of marine derived biogenic volatile organic compounds (BVOCs), such isoprene and terpene compounds, from algal bloom events. Our experimental results indicate that benzene ion chemistry is an attractive candidate for field measurements, and the RH dependence is weak. To further understand the advantages and limitations of this approach, we have also used electronic structure theory calculations to compliment the experimental work. These theoretical methods can provide valuable insight into the physical chemistry of ion molecule reactions including thermodynamical information, the stability of ions to fragmentation, and potential sources of interference such as dehydration to form isobaric ions. The combined experimental and computational approach also allows validation of the theoretical methods and will provide useful information towards gaining predictive power for the selection of appropriate reagent ions for future experiments.

  9. Common Host-Derived Chemicals Increase Catches of Disease-Transmitting Mosquitoes and Can Improve Early Warning Systems for Rift Valley Fever Virus

    PubMed Central

    Tchouassi, David P.; Sang, Rosemary; Sole, Catherine L.; Bastos, Armanda D. S.; Teal, Peter E. A.; Borgemeister, Christian; Torto, Baldwyn

    2013-01-01

    Rift Valley fever (RVF), a mosquito-borne zoonosis, is a major public health and veterinary problem in sub-Saharan Africa. Surveillance to monitor mosquito populations during the inter-epidemic period (IEP) and viral activity in these vectors is critical to informing public health decisions for early warning and control of the disease. Using a combination of field bioassays, electrophysiological and chemical analyses we demonstrated that skin-derived aldehydes (heptanal, octanal, nonanal, decanal) common to RVF virus (RVFV) hosts including sheep, cow, donkey, goat and human serve as potent attractants for RVFV mosquito vectors. Furthermore, a blend formulated from the four aldehydes and combined with CO2-baited CDC trap without a light bulb doubled to tripled trap captures compared to control traps baited with CO2 alone. Our results reveal that (a) because of the commonality of the host chemical signature required for attraction, the host-vector interaction appears to favor the mosquito vector allowing it to find and opportunistically feed on a wide range of mammalian hosts of the disease, and (b) the sensitivity, specificity and superiority of this trapping system offers the potential for its wider use in surveillance programs for RVFV mosquito vectors especially during the IEP. PMID:23326620

  10. Chemical solution deposition derived (001)-oriented epitaxial BiFeO{sub 3} thin films with robust ferroelectric properties using stoichiometric precursors (invited)

    SciTech Connect

    Zhang, Qi; Valanoor, Nagarajan; Standard, Owen, E-mail: o.standard@unsw.edu.au [School of Materials Science and Engineering, The University of New South Wales, Sydney, New South Wales 2052 (Australia)

    2014-08-14

    Phase pure bismuth ferrite (BiFeO{sub 3}) thin films with (001)-oriented epitaxial structure are realized on lanthanum strontium manganite (La{sub 0.67}Sr{sub 0.33}MnO{sub 3}) buffered (001)-SrTiO{sub 3} substrates by chemical solution deposition. The annealing process is optimized such that a stoichiometric precursor can be used to accurately control the Bi:Fe ratio. Ferroelectric, dielectric, and resistive switching behaviours are investigated for 40?nm, 70?nm, and 150?nm BFO thin films. While the thinnest film (40?nm) shows very leaky loops, square and fully saturated polarization hysteresis loops are shown for the thicker films. The highest remanent polarization (2P{sub r}?=?100??C/cm{sup 2}) and relative dielectric constant (?{sub r}?=?613) are obtained in the 150?nm BFO thin film. High cycle fatigue tests show that the thick films are resistant to polarization fatigue. Piezoresponse force microscopy results show that the domain structure varies with thickness. Resistive switching and polarization mediated diode effects are also observed. These robust properties suggest that chemical solution deposition derived BiFeO{sub 3} thin films can offer a viable low cost alternative.

  11. Quantum chemical investigation and statistical analysis of the relationship between corrosion inhibition efficiency and molecular structure of xanthene and its derivatives on mild steel in sulphuric acid

    NASA Astrophysics Data System (ADS)

    Obi-Egbedi, N. O.; Obot, I. B.; El-Khaiary, Mohammad I.

    2011-09-01

    A density functional theory (DFT) study of xanthene (XEN) and two of its derivatives namely xanthone (XAN) and xanthione (XION) recently used as corrosion inhibitors for mild steel in 0.5 M H 2SO 4 was undertaken at the B3LYP/631G (d) level. Inhibition efficiency obtained experimentally followed the order: XEN < XAN < XION. It was found that when the organic molecules adsorbed on the steel surface, molecular structure influences their interaction mechanism and by extension their inhibition efficiencies. The quantum chemical properties/descriptors most relevant to their potential action as corrosion inhibitors have been calculated in the neutral and protonated forms in aqueous phase for comparison. They include: Total energy (TE), EHOMO, ELUMO, energy gap (? E), dipole moment ( D), molecular area (MA), molecular volume (MV), hardness (?), softness ( ??), the fractions of electrons transferred (? N), electrophilicity index (?) and total energy change (? ET). The quantum chemical parameters/descriptors were correlated with inhibition effect of the three inhibitors and were further used to explain the electron transfer mechanism between the inhibitors and the steel surface. Furthermore, equations were proposed using the non-linear and the multiple-linear regression analysis. The theoretical obtained results were found to be consistent with the experimental data reported.

  12. Liquid chromatography tandem mass spectrometry determination of chemical markers and principal component analysis of Vitex agnus-castus L. fruits (Verbenaceae) and derived food supplements.

    PubMed

    Mari, Angela; Montoro, Paola; Pizza, Cosimo; Piacente, Sonia

    2012-11-01

    A validated analytical method for the quantitative determination of seven chemical markers occurring in a hydroalcoholic extract of Vitex agnus-castus fruits by liquid chromatography electrospray triple quadrupole tandem mass spectrometry (LC/ESI/(QqQ)MSMS) is reported. To carry out a comparative study, five commercial food supplements corresponding to hydroalcoholic extracts of V. agnus-castus fruits were analysed under the same chromatographic conditions of the crude extract. Principal component analysis (PCA), based only on the variation of the amount of the seven chemical markers, was applied in order to find similarities between the hydroalcoholic extract and the food supplements. A second PCA analysis was carried out considering the whole spectroscopic data deriving from liquid chromatography electrospray linear ion trap mass spectrometry (LC/ESI/(LIT)MS) analysis. High similarity between the two PCA was observed, showing the possibility to select one of these two approaches for future applications in the field of comparative analysis of food supplements and quality control procedures. PMID:22840980

  13. Flavonols and derivatives of gallic acid from young leaves of Toona sinensis (A. Juss.) Roemer and evaluation of their anti-oxidant capacity by chemical methods

    PubMed Central

    Yang, Huan; Gu, Qinying; Gao, Tingting; Wang, Xubo; Chue, Phenwei; Wu, Qinan; Jia, Xiaobin

    2014-01-01

    Background: Toona sinensis (A. Juss.) Roemer is an endemic species of Toona genus native to Asia. Its crude extract exhibits an effective anti-oxidant capacity against oxidative models, but the intrinsic substances responsible for this capacity in the extract remains unclear and is yet to be studied comprehensively. Objective: To investigate the chemical constituents of the young leaves of Toona sinensis and its anti-oxidant capacity. Materials and Methods: Silica gel column chromatography, preparative high-performance liquid chromatography (HPLC), nuclear magnetic resonance (NMR), and mass spectrometry (MS) were used to isolate and characterize the chemical constituents. Four chemical-induced oxidative models including DPPH free-radical scavenging assay, phenazine methosulphate (PMS) nicotinamide adenine dinucleotide (NADH) PMS-NADH-NBT superoxide anion scavenging assay, FeCl3-K3Fe (CN)6 reducing power assay, and FeCl2-FerroZine metal chelation assay were applied in the present study for evaluating anti-oxidant capacity. Results: Five flavonols and three derivatives of gallic acid, including quercetrin, kaempferol-3-O-?-L-rhamopyranoside, astragalin, quercetin, kaempferol, methyl gallate, ethyl gallate, and 1, 2, 3, 4, 6-penta-O-galloyl-?-D-glucopyranose were isolated from the leaves. Results showed that these compounds exhibited various antioxidant properties, markedly either as the strong scavengers for superoxide and free radicals or as molecules that were reducing or metal chelating in nature. Conclusion: The findings suggested that the 8 compounds in the young leaves of T. sinensis that were isolated in our study were the active compounds responsible for its antioxidant activity. These compounds can be utilized as a potential health supplement, as an available source of natural antioxidants, and as an effective material in pharmaceutical applications. PMID:24914286

  14. The chemically synthesized ageladine A-derivative LysoGlow84 stains lysosomes in viable mammalian brain cells and specific structures in the marine flatworm Macrostomum lignano.

    PubMed

    Mordhorst, Thorsten; Awal, Sushil; Jordan, Sebastian; Petters, Charlotte; Sartoris, Linda; Dringen, Ralf; Bickmeyer, Ulf

    2015-02-01

    Based on the chemical structure and the known chemical synthesis of the marine sponge alkaloid ageladine A, we synthesized the ageladine A-derivative 4-(naphthalene-2-yl)-1H-imidazo[4,5-c]pyridine trifluoroacetate (LysoGlow84). The two-step synthesis started with the Pictet-Spengler reaction of histamine and naphthalene-2-carbaldehyde to a tetrahydropyridine intermediate, which was dehydrogenated with activated manganese (IV) oxide to LysoGlow84. Structure and purity of the synthesized LysoGlow84 were confirmed by NMR spectroscopy and mass spectrometry. The fluorescence intensity emitted by LysoGlow84 depended strongly on the pH of the solvent with highest fluorescence intensity recorded at pH 4. The fluorescence maximum (at 315 nm excitation) was observed at 440 nm. Biocompatibility of LysoGlow84 was investigated using cultured rat brain astrocytes and the marine flatworm Macrostomum lignano. Exposure of the astrocytes for up to 6 h to micromolar concentrations of LysoGlow84 did not compromise cell viability, as demonstrated by several viability assays, but revealed a promising property of this compound for staining of cellular vesicles. Conventional fluorescence microscopy as well as confocal scanning microscopy of LysoGlow84-treated astrocytes revealed co-localization of LysoGlow84 fluorescence with that of LysoTracker® Red DND-99. LysoGlow84 stained unclear structures in Macrostomum lignano, which were identified as lysosomes by co-staining with LysoTracker. Strong fluorescence staining by LysoGlow84 was further observed around the worms' anterior gut and the female genital pore which were not counterstained by LysoTracker Red. Thus, LysoGlow84 is a new promising dye that stains lysosomes and other acidic compartments in cultured cells and in worms. PMID:25679913

  15. Three New and Eleven Known Unusual C25 Steroids: Activated Production of Silent Metabolites in a Marine-Derived Fungus by Chemical Mutagenesis Strategy using Diethyl Sulphate

    PubMed Central

    Xia, Ming-Wen; Cui, Cheng-Bin; Li, Chang-Wei; Wu, Chang-Jing

    2014-01-01

    Three new (1–3) and 11 known (4–14) C25 steroids with an unusual bicyclo[4.4.1]A/B ring system were isolated by tracing newly produced metabolites in the EtOAc extract of an antitumor mutant AD-1-2 obtained by the diethyl sulphate (DES) mutagenesis of a marine-derived Penicillium purpurogenum G59. HPLC-PDAD-UV and HPLC-ESI-MS analyses indicated that the G59 strain did not produce these metabolites and the production of 1–14 in the mutant AD-1-2 extract was caused by the activation of silent metabolites in the original G59 strain by DES mutagenesis. The structures of the new compounds, named antineocyclocitrinols A (1) and B (2) and 23-O-methylantineocyclocitrinol (3), including their absolute configurations were determined by various spectroscopic methods, especially the NMR and Mo2-induced CD analyses. Compounds 1–3 provide the first examples of the C25 bicyclo[4.4.1]A/B ring steroids with the Z-configuration of 20,22-double bond. All of 1–14 weakly inhibited several human cancer cell lines to varying extents. These results provided additional examples for the successful application of the chemical mutagenesis strategy using DES to discover new compounds by activating silent metabolites in fungal isolates and supported also the effectiveness and usefulness of this new strategy. PMID:24633254

  16. The epigenetic promotion of osteogenic differentiation of human adipose-derived stem cells by the genetic and chemical blockade of histone demethylase LSD1.

    PubMed

    Ge, Wenshu; Liu, Yunsong; Chen, Tong; Zhang, Xiao; Lv, Longwei; Jin, Chanyuan; Jiang, Yong; Shi, Lei; Zhou, Yongsheng

    2014-07-01

    Human adipose-derived stem cells (hASCs) are a highly attractive source in bone tissue engineering. It has become increasingly clear that chromatin regulators play an important role in cell fate determination. However, how osteogenic differentiation of hASCs is controlled by epigenetic mechanisms is not fully understood. Here we use genetic tools and chemical inhibitors to modify the epigenetic program of hASCs and identify lysine-specific demethylase 1 (LSD1), a histone demethylase that specifically catalyzes demethylation of di- and mono- methyl histone H3 lysine 4 (H3K4me2/1), as a key regulator in osteogenic differentiation of hASCs. Specifically, we demonstrated that genetic depletion of LSD1 with lentiviral strategy for gene knockdown promoted osteogenic differentiation of hASCs by cell studies and xenograft assays. At the molecular level, we found that LSD1 regulates osteogenesis-associated genes expression through its histone demethylase activity. Significantly, we demonstrated LSD1 demethylase inhibitors could efficiently block its catalytic activity and epigenetically boost osteogenic differentiation of hASCs. Altogether, our study defined the functional and biological roles of LSD1 and extensively explored the effects of its enzymatic activity in osteogenic differentiation of hASCs. A better understanding of how LSD1 influences on osteogenesis associated epigenetic events will provide new insights into the modulation of hASCs based cell therapy and improve the development of bone tissue engineering with epigenetic intervention. PMID:24794925

  17. Comparative investigation on chemical looping combustion of coal-derived synthesis gas containing H2S over supported NiO oxygen carriers

    SciTech Connect

    Ksepko, E.; Siriwardane, R.; Tian, H.; Simonyi, T.; Sciazko, M.

    2010-01-01

    Chemical looping combustion (CLC) of simulated coal-derived synthesis gas was conducted with NiO oxygen carriers supported on SiO2, ZrO2, TiO2, and sepiolite. The effect of H2S on the performance of these samples for the CLC process was also evaluated. Five-cycle thermogravimetric analysis (TGA) tests at 800 #1;C indicated that all oxygen carriers had a stable performance at 800 #1;C, except NiO/SiO2. Full reduction/oxidation reactions of the oxygen carrier were obtained during the five-cycle test. It was found that support had a significant effect on reaction performance of NiO both in reduction and oxidation rates. The reduction reaction was significantly faster than the oxidation reaction for all oxygen carriers, while the oxidation reaction is fairly slow due to oxygen diffusion on NiO layers. The reaction profile was greatly affected by the presence of H2S, but there was no effect on the capacity due to the presence of H2S in synthesis gas. The presence of H2S decreased reduction reaction rates significantly, but oxidation rates of reduced samples increased. X-ray diffraction (XRD) data of the oxidized samples after a five-cycle test showed stable crystalline phases without any formation of sulfides or sulfites/sulfates. Increase in reaction temperature to 900 #1;C had a positive effect on the performance.

  18. Chemical constituents from Kandelia candel with their inhibitory effects on pro-inflammatory cytokines production in LPS-stimulated bone marrow-derived dendritic cells (BMDCs).

    PubMed

    Dat, Le Duc; Thao, Nguyen Phuong; Tai, Bui Huu; Luyen, Bui Thi Thuy; Kim, Sohyun; Koo, Jung Eun; Koh, Young Sang; Cuong, Nguyen The; Thanh, Nguyen Van; Cuong, Nguyen Xuan; Nam, Nguyen Hoai; Kiem, Phan Van; Minh, Chau Van; Kim, Young Ho

    2015-04-01

    Chemical investigation of Kandelia candel resulted in the isolation of 19 compounds (1-19), including one new sesquiterpene glycoside, kandelside (1), three megastigman glycoside compounds (7-9), 16 known phenolic compounds (2-6 and 10-19). Structures of the isolated compounds were elucidated based on spectral data comparison with reported values. Isolated compounds were also evaluated for their inhibitory effects on the production of pro-inflammatory cytokines interleukin (IL)-12 p40, IL-6, and tumor necrosis factor ? (TNF-?) in lipopolysaccharide (LPS)-stimulated bone marrow-derived dendritic cells. Among these compounds, compound 9 exhibited strong inhibitory activity against IL-6 production (IC50=0.07 ± 0.05 ?M) and moderate inhibitory activity against TNF-? production (IC50=49.86 ± 1.02 ?M), but exhibited no activity on IL-12 p40 production. Compounds 5 and 6 significantly inhibited IL-12 p40, IL-6, and TNF-? production with IC50 values of 11.68 ± 0.38, 44.52 ± 1.08, and 28.73 ± 0.96 ?M, respectively. PMID:25769817

  19. Stabilization of asphaltenes in aliphatic solvents using alkylbenzene-derived amphiphiles. 1. Effect of the chemical structure of amphiphiles on asphaltene stabilization

    SciTech Connect

    Chang, C.L.; Fogler, H.S. (Univ. of Michigan, Ann Arbor, MI (United States))

    1994-06-01

    Stabilization of crude oil asphaltenes in apolar alkane solvents was investigated using a series of alkylbenzene-derived amphiphiles as the asphaltene stabilizers. In this paper (i.e., part I), we present the study on the influences of the chemical structure of these amphiphiles on the effectiveness of asphaltene solubilization and on the strength of asphaltene-amphiphile interaction using both UV/vis and FTIR spectroscopies. The results showed that the amphiphile's effectiveness of asphaltene stabilization was primarily controlled by the polarity of the amphiphile's head group and the length of the amphiphile's alkyl tail. Increasing the acidity of the amphiphile's head group could promote the amphiphile's ability to stabilize asphaltenes by increasing the acid-base attraction between asphaltenes and amphiphiles. On the other hand, although decreasing the amphiphile's tail length increased the asphaltene-amphiphile attraction slightly, it still required a minimum tail length (six carbons for p-alkylphenol amphiphiles) for amphiphiles to form stable steric layers around asphaltenes. We also found additional acidic side groups of amphiphiles could further improve the amphiphile's ability to stabilize asphaltenes. The effect of the molecular weight of alkane solvents on the amphiphile's ability to stabilize asphaltenes was also studied. 18 refs., 12 figs., 3 tabs.

  20. An intercomparison and evaluation of aircraft-derived and simulated CO from seven chemical transport models during the TRACE-P experiment

    Microsoft Academic Search

    Christopher M. Kiley; Henry E. Fuelberg; Paul I. Palmer; Dale J. Allen; Gregory R. Carmichael; Daniel J. Jacob; Celine Mari; R. Bradley Pierce; Kenneth E. Pickering; Youhua Tang; Oliver Wild; T. Duncan Fairlie; Jennifer A. Logan; Glen W. Sachse; Todd K. Shaack; David G. Streets

    2003-01-01

    Four global scale and three regional scale chemical transport models are intercompared and evaluated during NASA's Transport and Chemical Evolution over the Pacific (TRACE-P) experiment. Model simulated and measured CO are statistically analyzed along aircraft flight tracks. Results for the combination of 11 flights show an overall negative bias in simulated CO. Biases are most pronounced during large CO events.

  1. Transformation of quercitols into 4-methylenecyclohex-5-ene-1,2,3-triol derivatives, precursors for the chemical chaperones N-octyl-4-epi-?-valienamine (NOEV) and N-octyl-?-valienamine (NOV).

    PubMed

    Kuno, Shinichi; Takahashi, Atsushi; Ogawa, Seiichiro

    2011-12-01

    (+)-proto-Quercitol (1) and (-)-vibo-quercitol (2), both of which could be readily prepared by the bioconversion of myo-inositol, were successfully converted into the corresponding 4-methylenecyclohex-5-ene-1,2,3-triol derivatives. These compounds were demonstrated to be suitable precursors, preserving their configurations, for bioactive carba-aminosugars such as the potent chemical chaperone drug candidates, N-octyl-4-epi-?-valienamine (NOEV, 3) and N-octyl-?-valienamine (NOV, 4). PMID:22001090

  2. Transformation of quercitols into 4-methylenecyclohex-5-ene-1,2,3-triol derivatives, precursors for the chemical chaperones N-octyl-4- epi-?-valienamine ( NOEV) and N-octyl-?-valienamine ( NOV)

    Microsoft Academic Search

    Shinichi Kuno; Atsushi Takahashi; Seiichiro Ogawa

    2011-01-01

    (+)-proto-Quercitol (1) and (?)-vibo-quercitol (2), both of which could be readily prepared by the bioconversion of myo-inositol, were successfully converted into the corresponding 4-methylenecyclohex-5-ene-1,2,3-triol derivatives. These compounds were demonstrated to be suitable precursors, preserving their configurations, for bioactive carba-aminosugars such as the potent chemical chaperone drug candidates, N-octyl-4-epi-?-valienamine (NOEV, 3) and N-octyl-?-valienamine (NOV, 4).

  3. The comparison of surface characteristics, physico-chemical and biological properties of 304 stainless steel coated by melt-derived and sol–gel-derived 45S5 bioglass for orthopedic applications

    Microsoft Academic Search

    Ali Pedram; S. Morteza Naghib; Amin Feizpour; Mojtaba Ansari

    The ability of 45S5 bioglass to form a bond to living bone tissue and stimulate bone-cell proliferation may be different for melt- and sol–gel-derived samples. In this research, the differences in corrosion resistance, bioactivity and physical properties between the melt- and sol–gel-derived 45S5 bioglass coated on the surface of austenitic 304 stainless steel (SS) as a dental and orthopedic metallic

  4. Organic–inorganic hybrid solar cells based on conducting polymer and SnO 2 nanoparticles chemically modified with a fullerene derivative

    Microsoft Academic Search

    Naomi Kudo; Yuta Shimazaki; Hideo Ohkita; Masataka Ohoka; Shinzaburo Ito

    2007-01-01

    Organic–inorganic hybrid solid solar cells were fabricated by using a conjugated polymer (MDMO-PPV) and SnO2 nanoparticles chemically modified with C60C(COOH)2. The cell performance was improved by the chemical modification, suggesting that the modification with photoelectrochemically active organic materials is useful for establishing good electronic junction at the organic–inorganic interface. The short-circuit current density JSC increased with increasing thickness of MDMO-PPV

  5. Synthesis and reactions of a nucleoside derivative of phosphoric sulfonic anhydride. Studies related to the mechanisms of coupling reactions in the chemical synthesis of oligodeoxyribonucleotides by phosphotriester procedures.

    PubMed Central

    Dabkowski, W; Skrzypczynski, Z; Michalski, J; Piel, N; McLaughlin, L W; Cramer, F

    1984-01-01

    The synthesis of a model compound, diphenylphosphoric toluene-p-sulfonic anhydride, an arylsubstituted phosphoric sulfonic mixed anhydride, is described. Using the same procedure a thymidyl substituted derivative was prepared. The phosphoric sulfonic anhydride is the presumed intermediate in oligonucleotide coupling reactions involving phosphodiester activation by arenesulfonyl derivatives. This mixed anhydride reacts with a variety of nucleophiles. It can be converted to phophotriester derivatives in the presence of simple alcohols. Phosphotriester formation using the 5'-hydroxyl of a thymidine derivative requires additionally a catalyst such as N-methylimidazole. The reactive intermediate produced upon the addition of N-methylimidazole to the phosphoric sulfonic anhydride has been observed spectroscopically using 31P-NMR. PMID:6549065

  6. Chemical Evolution

    E-print Network

    Francesca Matteucci

    2007-04-05

    In this series of lectures we first describe the basic ingredients of galactic chemical evolution and discuss both analytical and numerical models. Then we compare model results for the Milky Way, Dwarf Irregulars, Quasars and the Intra-Cluster- Medium with abundances derived from emission lines. These comparisons allow us to put strong constraints on the stellar nucleosynthesis and the mechanisms of galaxy formation.

  7. Removal of the feldspar-derived luminescence component from polymineral fine silt samples for optical dating applications: evaluation of chemical treatment protocols and quality control procedures

    Microsoft Academic Search

    Barbara Mauz; Andreas Lang

    In optical dating of fine silt samples, the use of the quartz fraction only is often preferred. This approach requires the elimination of contaminating luminescence signals from feldspars. We compare here the effectiveness of different chemical treatments using diluted and concentrated hydrofluoric (HF) acid, and describe different tests to monitor the extent of feldspar contamination. The results suggest that the

  8. A conformational ensemble derived using NMR methyl chemical shifts reveals a mechanical clamping transition that gates the binding of the HU protein to DNA.

    PubMed

    Kannan, Arvind; Camilloni, Carlo; Sahakyan, Aleksandr B; Cavalli, Andrea; Vendruscolo, Michele

    2014-02-12

    Recent improvements in the accuracy of structure-based methods for the prediction of nuclear magnetic resonance chemical shifts have inspired numerous approaches for determining the secondary and tertiary structures of proteins. Such advances also suggest the possibility of using chemical shifts to characterize the conformational fluctuations of these molecules. Here we describe a method of using methyl chemical shifts as restraints in replica-averaged molecular dynamics (MD) simulations, which enables us to determine the conformational ensemble of the HU dimer and characterize the range of motions accessible to its flexible ?-arms. Our analysis suggests that the bending action of HU on DNA is mediated by a mechanical clamping mechanism, in which metastable structural intermediates sampled during the hinge motions of the ?-arms in the free state are presculpted to bind DNA. These results illustrate that using side-chain chemical shift data in conjunction with MD simulations can provide quantitative information about the free energy landscapes of proteins and yield detailed insights into their functional mechanisms. PMID:24517490

  9. Chemical modification of ?-glucocerebrosidase inhibitor N-octyl-?-valienamine: synthesis and biological evaluation of N-alkanoyl and N-alkyl derivatives

    Microsoft Academic Search

    Seiichiro Ogawa; Yuko Kobayashi; Kazuya Kabayama; Masayuki Jimbo; Jin-ichi Inokuchi

    1998-01-01

    Several N-alkanoyl 4a–d and N-alkyl derivatives 5a–g of the potent ?-glucocerebrosidase inhibitor N-octyl ?-valienamine (3) were synthesized in order to elucidate a role of hydrophobic portion in the inhibitory action. Although the former lacked inhibitory potency, the latter were strong ?-glucocerebrosidase inhibitors (cf. N-decyl-N-octyl-?-valienamine 5d: Ki 6.6×10?8M). Furthermore, when being prescribed into mouse-derived B16 melanoma cells, N-butyl-N-octyl-?-valienamine 5a and 5d

  10. Validity of Methods to Predict the Respiratory Sensitizing Potential of Chemicals: A Study with a Piperidinyl Chlorotriazine Derivative That Caused an Outbreak of Occupational Asthma

    Microsoft Academic Search

    Jeroen A. J. Vanoirbeek; Cindy Mandervelt; Albert R. Cunningham; Peter H. M. Hoet; Haiyan Xu; Hadewijch M. Vanhooren; Benoit Nemery

    2003-01-01

    A piperidinyl chlorotriazine (PCT) derivative, used as a plastic UV-stabilizer, caused an outbreak of occupational asthma. We verified, in BALB\\/c mice, the sensitizing potential of PCT in comparison to a known respiratory sensitizer (toluene diisocya- nate (TDI)) and a known dermal sensitizer (oxazolone), using three different methods in order to evaluate the validity of current models of sensitization. These included

  11. New modified ?-cyclodextrin derivatives as detoxifying agents of chemical warfare agents (II). In vitro detoxification of cyclosarin (GF): general screening and toxicokinetic aspects of OP scavengers.

    PubMed

    Müller, Susanne; Estour, François; Kalakuntla, Raman Kumar; Le Provost, Romain; Lafont, Olivier; Worek, Franz; Thiermann, Horst; Reiter, Georg

    2013-02-01

    As standard therapy of intoxication with organophosphorus (OP) compounds is still insufficient, developing new treatment strategies is urgently required. For evaluating potential of OP detoxification of several compounds correctly, different toxicodynamic impact of OP enantiomers has to be considered thoroughly. It has already been demonstrated that ?-cyclodextrin (?-CD) derivatives with attached nucleophilic substituent iodosobenzoic acid (IBA) can be regarded as potent OP scavengers due to an accelerating effect on decay of different OP. Herein, six CD derivatives permethylated or not on CD torus as well as differently attached nucleophilic substituent IBA derivative were investigated regarding detoxification of GF as an OP model substance. Acceleration of GF detoxification could be detected for all compounds with highest rate constants for propylene chain linked nucleophilic substituents on CD derivative. In addition, fast initial binding of GF on CD could be observed and is ascribed to formation of CD complexes. Furthermore, terminal plateau phase was detected of about 1% of each enantiomer reflecting the necessity of a quantitative determination at low concentrations. Moreover, this molecular depot formation may represent an additional detoxification pathway for OP. PMID:23201438

  12. Micro-ion beam analysis of physico-chemical reactions at the interface between sol-gel derived glass particles in

    E-print Network

    Boyer, Edmond

    minutes of interaction and the glass particles are progressively coated with this thin film. Traces-gel derived glass particles in the SiO2-CaO system and biological fluids J. Lao1 , J.M. Nedelec2 , Ph. Moretto the sensitivity of ion beam analysis methods to char- acterize in vitro the bioactive glass/biological fluids

  13. Crystallinity and Surface Morphology of Chemical Solution Derived Epitaxial Bi4Ti3O12 Thin Films on (100)LaAlO3

    Microsoft Academic Search

    Kyu-Seog Hwang; Yeon-Hum Yun; Yun-Ho Kim; Hyun-Wook Ryu; Bo-An Kang

    2002-01-01

    Bi4Ti3O12 thin films were prepared on single-crystal (100)LaAlO3 substrates by chemical solution deposition using metal naphthenates as starting materials. Precursor films were pyrolyzed at 500°C for 10 min in air and finally annealed at 650, 700, 750 and 800°C for 30 min in air, followed by rapid cooling. Crystallinity and in-plane alignment of the thin films were investigated by X-ray

  14. Determination of Melamine and Derivatives in Foods by Liquid Chromatography Coupled to Atmospheric Pressure Chemical Ionization Mass Spectrometry and Diode Array Detection

    Microsoft Academic Search

    Pilar Viñas; Natalia Campillo; Gema Férez-Melgarejo; Manuel Hernández-Córdoba

    2012-01-01

    Two liquid chromatographic methods based on atmospheric pressure chemical ionization mass spectrometry (LC-APCI-MS) and diode array detection (DAD) are evaluated for the rapid determination of melamine (MEL) and structurally related compounds, including ammeline (AMN), ammelide (AMD) and cyanuric acid (CA) in foods. Both procedures used ion-exchange LC and isocratic elution. Samples were extracted by homogenization with acetonitrile\\/water\\/diethylamine. Specificity was demonstrated

  15. Effect of Film Thickness on Electrical Properties of Chemical Solution Deposition-Derived Pb(ZrxTi1-x)O3\\/LaNiO3\\/Si

    Microsoft Academic Search

    Yoshihiro Sakamaki; Hiroaki Fukazawa; Naoki Wakiya; Hisao Suzuki; Kazuo Shinozaki; Tomoya Ohno; Marija Kosec

    2007-01-01

    Pb(ZrxTi1-x)O3 (PZT) thin films with different thicknesses and compositions near the morphotropic phase boundary (MPB) were deposited on a pseudocubic LaNiO3 (LNO) thin film electrode by chemical solution deposition (CSD) in order to elucidate effect of film thickness on the electrical properties of the resultant PZT thin films. The crystal symmetry of the resultant PZT thin films changed from tetragonal

  16. Cross-shelf and along-shelf nutrient fluxes derived from flow fields and chemical hydrography observed in the southern East China Sea off northern Taiwan

    Microsoft Academic Search

    Kon-Kee Liu; Tswen Yung Tang; Gwo-Ching Gong; Liang-Yu Chen; Fuh-Kwo Shiah

    2000-01-01

    Cross-shelf exchange of nutrients (N, P and Si) off northeastern Taiwan and along-shelf transports just north of the Taiwan Strait was assessed using chemical hydrography and velocity fields observed in August 1994 (summer) and March 1997 (winter). The summer survey was conducted along the periphery of a triangle. The velocity field was determined by phase-averaged current velocities measured with ship-borne

  17. Chemical synthesis of a polypeptide backbone derived from the primary sequence of the cancer protein NY-ESO-1 enabled by kinetically controlled ligation and pseudoprolines.

    PubMed

    Harris, Paul W R; Brimble, Margaret A

    2015-03-01

    The cancer protein NY-ESO-1 has been shown to be one of the most promising vaccine candidates although little is known about its cellular function. Using a chemical protein strategy, the 180 amino acid polypeptide, tagged with an arginine solubilizing tail, was assembled in a convergent manner from four unprotected peptide ?-thioester peptide building blocks and one cysteinyl polypeptide, which were in turn prepared by Boc and Fmoc solid phase peptide synthesis (SPPS) respectively. To facilitate the assembly by ligation chemistries, non-native cysteines were introduced as chemical handles into the polypeptide fragments; pseudoproline dipeptides and microwave assisted Fmoc SPPS were crucial techniques to prepare the challenging hydrophobic C-terminal fragment. Three sequential kinetically controlled ligations, which exploited the reactivity between peptide arylthioesters and peptide alkylthioesters, were then used in order to assemble the more tractable N-terminal region of NY-ESO-1. The ensuing 147 residue polypeptide thioester then underwent successful final native chemical ligation with the very hydrophobic C-terminal polypeptide bearing an N-terminal cysteine affording the 186 residue polypeptide as an advanced intermediate en route to the native NY-ESO-1 protein. © 2015 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 104: 116-127, 2015. PMID:25656702

  18. Chemical modification of beta-glucocerebrosidase inhibitor N-octyl-beta-valienamine: synthesis and biological evaluation of N-alkanoyl and N-alkyl derivatives.

    PubMed

    Ogawa, S; Kobayashi, Y; Kabayama, K; Jimbo, M; Inokuchi, J

    1998-10-01

    Several N-alkanoyl 4a-d and N-alkyl derivatives 5a-g of the potent beta-glucocerebrosidase inhibitor N-octyl beta-valienamine (3) were synthesized in order to elucidate a role of hydrophobic portion in the inhibitory action. Although the former lacked inhibitory potency, the latter were strong beta-glucocerebrosidase inhibitors (cf. N-decyl-N-octyl-beta-valienamine 5d: Ki 6.6 x 10(-8) M). Furthermore, when being prescribed into mouse-derived B16 melanoma cells, N-butyl-N-octyl-beta-valienamine 5a and 5d were shown to change the amount of GlcCer and GM3, which suggests that they are possibly introduced into cells and influence glycolipids biosynthesis. PMID:9839024

  19. Crystal Structure of Chemically Synthesized [N33A] Stromal Cell-Derived Factor 1alpha , a Potent Ligand for the HIV1 ``Fusin

    Microsoft Academic Search

    Chris Dealwis; Elias J. Fernandez; Darren A. Thompson; Reyna J. Simon; Michael A. Siani; Elias Lolis

    1998-01-01

    Stromal cell-derived factor-1alpha (SDF-1alpha ) is a member of the chemokine superfamily and functions as a growth factor and chemoattractant through activation of CXCR4\\/LESTR\\/Fusin, a G protein-coupled receptor. This receptor also functions as a coreceptor for T-tropic syncytium-inducing strains of HIV-1. SDF-1alpha antagonizes infectivity of these strains by competing with gp120 for binding to the receptor. The crystal structure of

  20. Lanolin and its derivatives

    Microsoft Academic Search

    Mitchell L. Schlossman; Justin P. McCarthy

    1978-01-01

    Lanolin, which is extensively used in pharmaceuticals and cosmetics, is generally considered to consist of a mixture of naturally\\u000a formed esters derived from higher alcohols and higher fatty acids. This paper encompasses the chemical description of lanolin;\\u000a the composition of its esters, acids, and alcohols; the chemical and physical modifications of lanolin; the refining of lanolin;\\u000a and some of its

  1. Local angular momentum-local impact parameter analysis: Derivation and properties of the fundamental identity, with applications to the F +H2, H +D2, and Cl +HCl chemical reactions

    NASA Astrophysics Data System (ADS)

    Monks, P. D. D.; Xiahou, Chengkui; Connor, J. N. L.

    2006-10-01

    The technique of local angular momentum-local impact parameter (LAM-LIP) analysis has recently been shown to provide valuable dynamical information on the angular scattering of chemical reactions under semiclassical conditions. The LAM-LIP technique exploits a nearside-farside (NF) decomposition of the scattering amplitude, which is assumed to be a Legendre partial wave series. In this paper, we derive the "fundamental NF LAM identity," which relates the full LAM to the NF LAMs (there is a similar identity for the LIP case). Two derivations are presented. The first uses complex variable techniques, while the second exploits an analogy between the motion of the scattering amplitude in the Argand plane with changing angle and the classical mechanical motion of a particle in a plane with changing time. Alternative forms of the fundamental LAM-LIP identity are described, one of which gives rise to a CLAM-CLIP plot, where CLAM denotes (Crosssection)×LAM and CLIP denotes (Crosssection)×LIP. Applications of the NF LAM theory, together with CLAM plots, are reported for state-to-state transitions of the benchmark reactions F +H2?FH+H, H +D2?HD+D, and Cl +HCl?ClH+Cl, using as input both numerical and parametrized scattering matrix elements. We use the fundamental LAM identity to explain the important empirical observation that a NF cross section analysis and a NF LAM analysis provide consistent (and complementary) information on the dynamics of chemical reactions.

  2. Derivatives Page

    NSDL National Science Digital Library

    Derivatives are financial securities whose value is derived from another "underlying" financial security. Options, futures, swaps, swaptions, and structured notes are all examples of derivative securities. Derivatives can be used in hedging, protecting against financial risk, or can be used to speculate on the movement of commodity or security prices, interest rates, or the levels of financial indices. The valuation of derivatives makes use of the statistical mathematics of uncertainty. With links to related articles. See also Derivatives Concepts A-Z, glossary of derivatives-related terminology designed to make the other articles in the Financial Pipeline's Derivatives section easier to understand.

  3. STEM and EDXS characterisation of physico-chemical reactions at the periphery of sol-gel derived Zn-substituted hydroxyapatites during interactions with biological fluids

    PubMed Central

    Jallot, Edouard; Nedelec, Jean-Marie; Grimault, Anne S.; Chassot, Emmanuelle; Grandjean-Laquerriere, Alexia; Laquerriere, Patrice; Laurent-Maquin, Dominique

    2005-01-01

    With its good properties of biocompatibility and bioactivity hydroxyapatite (HA) is highly used as bone substitutes and as coatings on metallic prostheses. In order to improve bioactive properties of HA we have elaborated Zn2+ doped hydroxyapatite. Zn2+ ions substitute for Ca2+ cations in the HA structure and four Zn concentrations (Zn/Zn+Ca) were prepared 0.5, 1, 2, 5 % at. To study physico-chemical reactions at the materials periphery, we immersed the bioceramics into biological fluids for delays from 1 day to 20 days. The surface changes were studied at the nanometer scale by scanning transmission electron microscopy associated to energy dispersive X-ray spectroscopy. After 20 days of immersion we observed the formation of a calcium-phosphate layer at the periphery of the HA doped with 5% of zinc. This layer contains magnesium and its thickness was around 200 nm. Formation of this Ca-P-Mg layer represents bioactivity properties of the 5% Zn-substituted hydroxyapatite. This biologically active layer improves properties of HA and will permit a chemical bond between the ceramic and bone. PMID:15893220

  4. Aggregation-induced emissions of tetraphenylethene derivatives and their utilities as chemical vapor sensors and in organic light-emitting diodes

    NASA Astrophysics Data System (ADS)

    Dong, Yongqiang; Lam, Jacky W. Y.; Qin, Anjun; Liu, Jianzhao; Li, Zhen; Tang, Ben Zhong; Sun, Jiaxin; Kwok, Hoi Sing

    2007-07-01

    Nonemissive tetraphenylethene (TPE) 1 and its diphenylated derivative 2 were induced to emit intensely by aggregate formation. Crystalline aggregates of the dyes emitted bluer lights than their amorphous counterparts. The emissions of the TPE dyes could be switched off and on continuously and reversibly by wetting and dewetting with solvent vapors, respectively, manifesting their ability to optically sense volatile organic compounds. The light-emitting diodes fabricated from 1 and 2 were turned on at ˜2.9 and ˜5V and emitted blue lights with maximum luminance of ˜1800 and ˜11000cd/m2, respectively.

  5. 40 CFR 721.10039 - Diethoxybenzenamine derivative, diazotized, coupled with aminonaphthalenesulfonic acid derivative...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...aminonaphthalenesulfonic acid derivative, ammonium salt (generic). 721.10039 Section 721...aminonaphthalenesulfonic acid derivative, ammonium salt (generic). (a) Chemical substance...aminonaphthalenesulfonic acid derivative, ammonium salt (PMN P-02-514) is subject to...

  6. 40 CFR 721.10039 - Diethoxybenzenamine derivative, diazotized, coupled with aminonaphthalenesulfonic acid derivative...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...aminonaphthalenesulfonic acid derivative, ammonium salt (generic). 721.10039 Section 721...aminonaphthalenesulfonic acid derivative, ammonium salt (generic). (a) Chemical substance...aminonaphthalenesulfonic acid derivative, ammonium salt (PMN P-02-514) is subject to...

  7. 40 CFR 721.10039 - Diethoxybenzenamine derivative, diazotized, coupled with aminonaphthalenesulfonic acid derivative...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...aminonaphthalenesulfonic acid derivative, ammonium salt (generic). 721.10039 Section 721...aminonaphthalenesulfonic acid derivative, ammonium salt (generic). (a) Chemical substance...aminonaphthalenesulfonic acid derivative, ammonium salt (PMN P-02-514) is subject to...

  8. Effect of interface structure on the chemical composition and electrical properties of sol-gel-derived LaNiO3 films

    NASA Astrophysics Data System (ADS)

    Zhu, M. W.; Wang, H. L.; Han, H. J.; Wang, Z. J.; Zhang, Z. D.

    2015-06-01

    In the present work, lanthanum nickel oxide (LNO) thin films are prepared with the sol-gel multilayer coating method. Lattice-matched SrTiO3 (STO) buffer layer is introduced to tailor the film-substrate interface. The effect of interface structure on the electrical properties, microstructure and chemical composition of LNO films is investigated. The results show that the improvement in the interface structure minimizes the effect of interface on the electrical properties of LNO films and leads to a sharp decrease in room-temperature resistivity of LNO films to 570 ?? cm, comparable to that of the LNO films on single-crystal STO substrate. This is ascribed to the decrease in structural disorder and the concentration of oxygen vacancies in the LNO films.

  9. 1H NMR spectroscopic investigations on the conformation of amphiphilic aromatic amino acid derivatives in solution: effect of chemical architecture of amphiphiles and polarity of solvent medium.

    PubMed

    Vijay, R; Mandal, A B; Baskar, Geetha

    2010-11-01

    In this study, the conformation of the amphiphilic lauryl esters of L-tyrosine (LET) and L-phenylalanine (LEP) in water and dimethyl sulfoxide is established. The alkyl chain protons of LEP in D(2)O appear at ? 1.010-1.398 and show an upfield shift and large line width, suggesting the proximity of the phenyl ring to the alkyl chain in contrast to that of LET. Quite interestingly, in DMSO-d(6), the (1)H NMR spectra of LET and LEP show a strong similarity that is suggestive of an orientation that positions the aromatic ring and aliphatic chain away from each other. These results are substantiated with two-dimensional nuclear Overhauser enhancement spectroscopy (2D NOSEY). Theoretical molecular models of the conformation at the interface corroborate the experimental findings. Investigations of the solvent polarity and chemical structure-dependent conformation are discussed. PMID:20942451

  10. Chemical composition and anti-mosquito potential of rhizome extract and volatile oil derived from Curcuma aromatica against Aedes aegypti (Diptera: Culicidae).

    PubMed

    Choochote, Wej; Chaiyasit, Dana; Kanjanapothi, Duangta; Rattanachanpichai, Eumporn; Jitpakdi, Atchariya; Tuetun, Benjawan; Pitasawat, Benjawan

    2005-12-01

    Crude rhizome extracts and volatile oils of Curcuma aromatica were evaluated for chemical composition and anti-mosquito potential, including larvicidal, adulticidal, and repellent activities against the Aedes aegypti mosquito. Chemical identification achieved by GC/MS analysis revealed that xanthorrhizol, 1H-3a, 7-methanoazulene and curcumene at 35.08 and 13.65%, 21.81 and 30.02%, and 13.75 and 25.71%, were the main constituents in hexane extracts and volatile oils, respectively. Volatile oil of Cu. aromatica possessed a significantly higher larvicidal activity against the 4th instar larvae of Ae. aegypti than that of hexane extracts, with LC50 values of 36.30 and 57.15 ppm, respectively. In testing for adulticidal activity, on the other hand, hexane-extracted Cu. aromatica (LC50: 1.60 microg/mg female) was found to be slightly more effective against female Ae. aegypti than volatile oil (LC50: 2.86 microg/mg female). However, the repellency of these two products against Ae. aegypti adult females differed significantly. The hexane-extracted Cu. aromatica, with a median complete protection time of 1 h (range = 1-1.5 h) when applied at a concentration of 25%, appeared to have significantly higher repellency than that of distillate oil (0.5 h, range = 0-0.5 h). The different results obtained from both products of Cu. aromatica were probably due to variety in quantity and type of active ingredients as well as the biological and physiological characteristics that differed between both developmental stages of mosquitoes, larvae, and adults. PMID:16599168

  11. Mammalian and teleost cell line bioassay and chemically derived 2,3,7,8-tetrachlorodibenzo-p-dioxin equivalent concentrations in lake trout (Salvelinus namaycush) from Lake Superior and Lake Ontario, North America

    SciTech Connect

    Whyte, J.J.; Heuvel, M.R. van den; Clemons, J.H.; Dixon, D.G.; Bols, N.C. [Univ. of Waterloo, Ontario (Canada). Dept. of Biology; Huestis, S.Y. [Dept. of Fisheries and Oceans, Burlington, Ontario (Canada); Servos, M.R. [Environment Canada, Burlington, Ontario (Canada). National Water Research Inst.

    1998-11-01

    For livers of lake trout from three Great Lakes sites, the 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) equivalent concentrations (TEQs) were determined in four ways. Bioassay-derived (BD) TEQs were measured with rat (H4IIE) and rainbow trout (RTL-W1) cell lines, and chemistry-derived (CD) TEQs were calculated with TCDD equivalency factors (TEFs) derived with H4IIE and RTL-W1. Generally, BD-TEQs and CD-TEQs for individual samples did not differ significantly for either H4IIE or RTL-W1, indicating that all of the AhR-active compounds in a sample were accounted for by the congener analysis and that these compounds acted in an additive fashion in both mammalian and piscine systems. However, contributions of individual chemicals to overall CD-TEQs differed with H4IIE and RTL-W1 TEFs, and for some individual samples. TEQs did depend on the method used. Hepatic TEQs and ethoxyresorufin-O-deethylase (EROD) levels differed significantly between sites. For TEQs, the order was Glenora > Jackfish Bay > Black Bay; for EROD activity, the order was Jackfish Bay > Glenora = Black Bay. No correlation was found between hepatic TEQs and EROD activity, which suggests that the two measurements are evaluating different but related consequences of contaminant exposure.

  12. Chemical constituents from a soil-derived actinomycete, Actinomadura miaoliensis BCRC 16873, and their inhibitory activities on lipopolysaccharide-induced tumor necrosis factor production.

    PubMed

    Tseng, Min; Su, Yung-Shun; Cheng, Ming-Jen; Liu, Ta-Wei; Chen, Ih-Sheng; Wu, Ming-Der; Chang, Hsun-Shuo; Yuan, Gwo-Fang

    2013-02-01

    An investigation on the secondary metabolites from the BuOH extract of the fermentation broth of the thermotolerant polyester-degrading actinomycete Actinomadura miaoliensis BCRC 16873 was carried out. One previously undescribed ?-pyrone (=pyran-2-one) derivative, designated as miaolienone (1), and a new butanolide, miaolinolide (2), together with 13 known compounds, 3-15, were obtained. Their structures were established on the basis of extensive 1D- and 2D-NMR analyses in combination with HR-MS experiments. In addition, the isolated compounds 1-15 were evaluated for the inhibitory effects of the isolates on the production of tumor necrosis factor (TNF-?) induced by lipopolysaccharide (LPS). Among the isolates, 1 and 2 significantly inhibited TNF-? production in U937 cells in vitro, and the IC(50) values were 0.59 and 0.76 ?M, respectively. Compounds 3-5 displayed moderate inhibitory activities on LPS-induced TNF-? production. PMID:23418178

  13. A comparative study of the microbiologic effectiveness of chemical disinfectants and peroxide-neutralizer systems.

    PubMed

    Rosenthal, R A; Stein, J M; McAnally, C L; Schlech, B A

    1995-04-01

    We evaluated the antimicrobial activity of chemical and hydrogen peroxide-neutralizer contact lens disinfection systems. The acute activity, storage, and recontamination potential of the two disinfection methods were compared by challenging the disinfectants with Staphylococcus spp., Pseudomonas aeruginosa, Serratia marcescens, Candida spp., and Aspergillus fumigatus. Chemical disinfectants preserved with polyquaternium-1 and polyhexamethylene biguanide and hydrogen peroxide-neutralizer systems with no additional preservatives were tested. Additionally, lens cases from patients using both systems were evaluated. Lens cases from patients using peroxide-neutralizer systems tended toward heavier contamination (31.8%) than the cases disinfected with a chemical system (20.3%, P = 0.16). The laboratory results showed that the differences in activity of chemical and peroxide-neutralizer systems was not statistically significant at the disinfection times against Staphylococcus epidermidis, S. marcescens, Candida parapsilosis, and A. fumigatus (P = 0.1037 to P = 0.5412). A statistical difference was shown against C. albicans (P = 0.0176) in favor of the peroxide-neutralizer systems. The reverse was true during storage. Although the chemical disinfectants maintained the population of microorganisms, the bacteria and yeast increased to over 10(7) CFU/mL in neutralized peroxide systems. Overall, the results emphasize the importance of contact lens products containing preservatives for lasting protection from microorganisms. PMID:7796529

  14. Synthesis and characterization of Cu and Co complexes derived from 2,4,6-tri-(2-pyridyl)-1,3,5-triazine (TPT) by chemical and tribochemical reactions

    Microsoft Academic Search

    Sawsan M. Al-Ashqar; Mohsen M. Mostafa

    2010-01-01

    Four Cu and Co complexes–[Cu(L1)Cl2(H2O)]3\\/2H2O · 1\\/2EtOH, [Cu(L1)2Cl2]6H2O, [Co(L1)Cl2]3H2O · EtOH, and [Co2(L1)(H2O)Cl4]1.5H2O · EtOH (L1 = 2,4,6-tri(2-pyridyl)-1,3,5-triazine; TPT)–were synthesized by conventional chemical method and used to synthesize another four metal complexes–[Cu(L1)I2(H2O)]6H2O, [Cu(L1)2I2]6H2O, [Co(L1)I(H2O)2]I · 2H2O, and [Co2(L1)I4(H2O)3]–using tribochemical reaction, by grinding it with KI. Substitution of chloride by iodide occurred, but no reduction for Cu or oxidation of Co.

  15. Impact of larger rare earth Pr3+ ions on the physical properties of chemically derived PrxCoFe2-xO4 nanoparticles

    NASA Astrophysics Data System (ADS)

    Pachpinde, A. M.; Langade, M. M.; Lohar, K. S.; Patange, S. M.; Shirsath, Sagar E.

    2014-01-01

    Rare earth Pr3+ ions with its larger ionic radii substituted CoFe2O4 nanoparticles with x ranging from 0.0 to 0.1 were synthesized by sol-gel auto-combustion chemical method. Powder X-ray diffraction (XRD), scanning electron microscopy (SEM), infrared spectroscopy (IR) and vibrating sample magnetometer (VSM) were employed to characterize the physical properties of these ferrite nanoparticles. XRD pattern reveals the formation of cubic spinel ferrite with the signature of PrFeO3 phases for x ? 0.05. SEM images show that the synthesized samples are in good homogeneity with uniformly distributed grain. The results of IR spectroscopy analysis indicated that the functional groups of cobalt spinel ferrite were formed during the sol-gel process. The cations distribution between the tetrahedral (A-site) and octahedral sites (B-site) has been estimated by XRD analysis. Room temperature magnetic measurement shows saturation magnetization and coercivity increased from 54.7 to 64.2 emu/g and 644 to 1013 Oe, respectively with the increasing Pr3+ substitution.

  16. An Intercomparison and Evaluation of Aircraft-Derived and Simulated CO from Seven Chemical Transport Models During the TRACE-P Experiment

    NASA Technical Reports Server (NTRS)

    Kiley, C. M.; Fuelberg, Henry E.; Palmer, P. I.; Allen, D. J.; Carmichael, G. R.; Jacob, D. J.; Mari, C.; Pierce, R. B.; Pickering, K. E.; Tang, Y.

    2002-01-01

    Four global scale and three regional scale chemical transport models are intercompared and evaluated during NASA's TRACE-P experiment. Model simulated and measured CO are statistically analyzed along aircraft flight tracks. Results for the combination of eleven flights show an overall negative bias in simulated CO. Biases are most pronounced during large CO events. Statistical agreements vary greatly among the individual flights. Those flights with the greatest range of CO values tend to be the worst simulated. However, for each given flight, the models generally provide similar relative results. The models exhibit difficulties simulating intense CO plumes. CO error is found to be greatest in the lower troposphere. Convective mass flux is shown to be very important, particularly near emissions source regions. Occasionally meteorological lift associated with excessive model-calculated mass fluxes leads to an overestimation of mid- and upper- tropospheric mixing ratios. Planetary Boundary Layer (PBL) depth is found to play an important role in simulating intense CO plumes. PBL depth is shown to cap plumes, confining heavy pollution to the very lowest levels.

  17. Assessment and Applications of NASA Ozone Data Products Derived from Aura OMI/MLS Satellite Measurements in Context of the GMI Chemical Transport Model

    NASA Astrophysics Data System (ADS)

    Ziemke, J. R.; Olsen, M. A.; Witte, J. C.; Douglass, A. R.

    2014-12-01

    Measurements from the Ozone Monitoring Instrument (OMI) and Microwave Limb Sounder (MLS), both onboard the Aura spacecraft, have been used to produce daily global maps of column and profile ozone since August 2004. Here we compare and evaluate three strategies to obtain daily maps of tropospheric and stratospheric ozone from OMI and MLS measurements: trajectory mapping, direct profile retrieval, and data assimilation. Evaluation is based on an assessment that includes validation using ozonesondes and comparisons with the Global Modeling Initiative (GMI) chemical transport model (CTM). We investigate applications of the three ozone data products from near-decadal and inter-annual timescales to day-to-day case studies. Inter-annual changes in zonal mean tropospheric ozone from all of the products in any latitude range are of the order 1-2 Dobson Units while changes (increases) over the 8-year Aura record investigated vary by 2-4 Dobson Units. It is demonstrated that all of the ozone products can measure and monitor exceptional tropospheric ozone events including major forest fire and pollution transport events. Stratospheric ozone during the Aura record has several anomalous inter-annual events including split stratospheric warmings in the Northern Hemisphere extra-tropics that are well captured using the data assimilation ozone profile product. Data assimilation with continuous daily global coverage and vertical ozone profile information is the best of the three strategies at generating a global tropospheric and stratospheric ozone product for science applications.

  18. Assessment and applications of NASA ozone data products derived from Aura OMI/MLS satellite measurements in context of the GMI chemical transport model

    NASA Astrophysics Data System (ADS)

    Ziemke, J. R.; Olsen, M. A.; Witte, J. C.; Douglass, A. R.; Strahan, S. E.; Wargan, K.; Liu, X.; Schoeberl, M. R.; Yang, K.; Kaplan, T. B.; Pawson, S.; Duncan, B. N.; Newman, P. A.; Bhartia, P. K.; Heney, M. K.

    2014-05-01

    Measurements from the Ozone Monitoring Instrument (OMI) and Microwave Limb Sounder (MLS), both on board the Aura spacecraft, have been used to produce daily global maps of column and profile ozone since August 2004. Here we compare and evaluate three strategies to obtain daily maps of tropospheric and stratospheric ozone from OMI and MLS measurements: trajectory mapping, direct profile retrieval, and data assimilation. Evaluation is based on an assessment that includes validation using ozonesondes and comparisons with the Global Modeling Initiative (GMI) chemical transport model. We investigate applications of the three ozone data products from near-decadal and interannual time scales to day-to-day case studies. Interannual changes in zonal mean tropospheric ozone from all of the products in any latitude range are of the order 1-2 Dobson units while changes (increases) over the 8 year Aura record investigated vary by 2-4 Dobson units. It is demonstrated that all of the ozone products can measure and monitor exceptional tropospheric ozone events including major forest fire and pollution transport events. Stratospheric ozone during the Aura record has several anomalous interannual events including split stratospheric warmings in the Northern Hemisphere extratropics that are well captured using the data assimilation ozone profile product. Data assimilation with continuous daily global coverage and vertical ozone profile information is the best of the three strategies at generating a global tropospheric and stratospheric ozone product for science applications.

  19. Constraints on eruption dynamics of basaltic explosive activity derived from chemical and microtextural study: The example of the Fontana Lapilli Plinian eruption, Nicaragua

    NASA Astrophysics Data System (ADS)

    Costantini, L.; Houghton, B. F.; Bonadonna, C.

    2010-01-01

    The Fontana Lapilli deposit is one of very few examples of basaltic Plinian eruptions discovered so far. Juvenile clasts have uniform chemical composition and moderate ranges of density and bulk vesicularity. However, clast populations include two textural varieties which are microlite-poor and microlite-rich respectively. These two clast types have the same clast density range, making a distinction impossible on that base alone. The high bubble number density (˜ 10 7 cm - 3 ) and small bubble population of the Fontana clasts suggest that the magma underwent coupled degassing following rapid decompression and fast ascent rate, leading to non-equilibrium degassing with continuous nucleation as it is common for silicic analogues. The Fontana products have lower microlite contents (10-60 vol.%) with respect to the other documented basaltic Plinian eruptions suggesting that the brittle fragmentation, implied for the other basaltic Plinian deposits, does not apply to the Fontana products and another fragmentation mechanism led the basaltic magma to erupt in a Plinian fashion.

  20. Assessment and Applications of NASA Ozone Data Products Derived from Aura OMI-MLS Satellite Measurements in Context of the GMI Chemical Transport Model

    NASA Technical Reports Server (NTRS)

    Ziemke, J. R.; Olsen, M. A.; Witte, J. C.; Douglass, A. R.; Strahan, S. E.; Wargan, K.; Liu, X.; Schoeberl, M. R.; Yang, K.; Kaplan, T. B.; Pawson, S.; Duncan, B. N.; Newman, P. A.; Bhartia, K.; Heney, M. K.

    2013-01-01

    Measurements from the Ozone Monitoring Instrument (OMI) and Microwave Limb Sounder (MLS), both onboard the Aura spacecraft, have been used to produce daily global maps of column and profile ozone since August 2004. Here we compare and evaluate three strategies to obtain daily maps of tropospheric and stratospheric ozone from OMI and MLS measurements: trajectory mapping, direct profile retrieval, and data assimilation. Evaluation is based upon an assessment that includes validation using ozonesondes and comparisons with the Global Modeling Initiative (GMI) chemical transport model (CTM). We investigate applications of the three ozone data products from near-decadal and inter-annual timescales to day-to-day case studies. Zonally averaged inter-annual changes in tropospheric ozone from all of the products in any latitude range are of the order 1-2 Dobson Units while changes (increases) over the 8-year Aura record investigated http://eospso.gsfc.nasa.gov/atbd-category/49 vary approximately 2-4 Dobson Units. It is demonstrated that all of the ozone products can measure and monitor exceptional tropospheric ozone events including major forest fire and pollution transport events. Stratospheric ozone during the Aura record has several anomalous inter-annual events including stratospheric warming split events in the Northern Hemisphere extra-tropics that are well captured using the data assimilation ozone profile product. Data assimilation with continuous daily global coverage and vertical ozone profile information is the best of the three strategies at generating a global tropospheric and stratospheric ozone product for science applications.

  1. In vitro proliferation and in vivo malignancy of cell lines simultaneously derived from a chemically-induced heterogeneous rat mammary tumor.

    PubMed

    Tagliaferri, F; Teodori, L; Valente, M G; Stipa, F; Cucina, A; Göhde, W; Colettii, D; Alo, P; Stipa, S

    2000-03-01

    Identification of clones in primary tumors responsible for proliferation, invasion, and metastasis was carried out. Four different aneuploid established cell lines derived from a ductal infiltrating mammary rat tumor induced by 7,12-dimethylbenz[a]anthracene were studied for proliferative and growth features in vitro and for tumorigenic and metastatic potential in vivo in nude mice. Clones, named RM1, RM2, RM3, and RM4, were characterized by different proliferative activity. Clone RM1 showed the highest proliferative activity by both tritiated thymidine incorporation and S-phase flow cytometry, followed by clone RM4. Conversely, clones RM2 and RM3 showed a lower proliferation rate. Growth-promoting activity, tested on 3T3 Swiss cells, was high in all clones, although RM1 showed significantly lower growth factors-releasing activity. Nude mice tumorigenesis demonstrated a strong tumor induction of line RM1 (100% of the mice after 47 +/- 7 d) and a slightly lower tumor induction of line RM4 (70% of the mice after 69 +/- 9 d). Line RM3 showed tumor induction in 40% of the mice after 186 +/- 16 d. Lines RM2 showed no tumor induction. Metastasis occurred in mice treated with line RM1 only. Therefore, tumorigenesis and metastasis correlate with proliferation but not with the release of growth factors. In conclusion, flow cytometry monitoring of clones from heterogeneous primary tumors proved to be a suitable model for the study of in vivo malignancy and in vitro proliferation. PMID:10777055

  2. Bone marrow-derived mesenchymal stem cell transplantation ameliorates oxidative stress and restores intestinal mucosal permeability in chemically induced colitis in mice

    PubMed Central

    Sun, Tao; Gao, Guang-Zhou; Li, Rong-Fu; Li, Xin; Li, Da-Wei; Wu, Shan-Shan; Yeo, Anthony ET; Jin, Bo

    2015-01-01

    Background: Ulcerative colitis (UC) can be viewed as an autoimmune disease. Bone marrow-derived mesenchymal stem cells (MSCs) with its regenerative, cellular multi-lineage and immunomodulatory abilities can influence the repair of damaged tissues in UC. This study investigated the effects of MSCs transplantation on the mice intestinal barrier in response to oxidative stress injury. Methods: Colitis was induced by daily consecutive administration of 5% dextran sulfate sodium (DSS) solution for 7 days. Male murine MSCs were isolated and transplanted into female mice via injection in the tail vein. Serum and colon specimens were collected at 12 h, 24 h, 3 d, 7 d and 14 d after injection. Serum levels of D-lactate (D-LAC), diamine oxidase (DAO), colonic levels of malondialdehyde (MDA) and superoxide dismutase (SOD) were quantified. The SRY protein of the male sex determinant gene expression and E-cadherin were also ascertained intracellularly. Results: Three days after receiving male MSCs transplantation, SRY protein expression was detected. The quantity increased on successive days. Serum levels of D-LAC and DAO, colonic MDA and SOD normalized in a shorter time period compared to controls (p<0.05). Not surprisingly, histological regeneration of tissue and E-cadherin expression in the colon of MSCs transplanted mice also occurred in a shorter time period than controls. Conclusions: Transplanted MSCs restored mucosal permeability, and minimized oxidative stress related injury. PMID:26175850

  3. Anti-inflammatory effects of methyl ursolate obtained from a chemically derived crude extract of apple peels: potential use in rheumatoid arthritis.

    PubMed

    Pádua, Tatiana A; de Abreu, Bianca S S C; Costa, Thadeu E M M; Nakamura, Marcos J; Valente, Lígia M M; Henriques, Maria das Graças; Siani, Antonio C; Rosas, Elaine C

    2014-11-01

    Ursolic acid (UA), a pentacyclic triterpene acid found in apple peels (Malus domestica, Borkh, Rosaceae), has a large spectrum of pharmacological effects. However, the vegetal matrix usually produces highly viscous and poorly soluble extracts that hamper the isolation of this compound. To overcome this problem, the crude EtOH-AcOEt extract of commercial apple peels was exhaustively treated with diazomethane, after which methyl ursolate (MU) was purified by column chromatography and characterized spectrometrically. The anti-inflammatory effects of UA and MU (50 mg/kg) were analyzed by zymosan-induced paw edema, pleurisy and in an experimental arthritis model. After 4 h of treatment with UA and MU, paw edema was reduced by 46 and 44 %, respectively. Both UA and MU inhibited protein extravasation into the thoracic cavity; tibio-femoral edema by 40 and 48 %, respectively; and leukocyte influx into the synovial cavity after 6 h by 52 and 73 %, respectively. Additionally, both UA and MU decreased the levels of mediators related to synovial inflammation, such as KC/CXCL-1 levels by 95 and 90 %, TNF-? levels by 76 and 71 %, and IL-1? levels by 57 and 53 %, respectively. Both the compounds were equally effective when assayed in different inflammatory models, including experimental arthritis. Hence, MU may be considered to be a useful anti-inflammatory derivative to overcome the inherent poor solubility of UA for formulating pharmaceutical products. PMID:24733672

  4. Part I. Naltrexone-derived conjugate addition ligands for opioid receptors. Part II. Chemical and enantioselective aspects of the metabolism of verapamil

    SciTech Connect

    Olsen, L.D.

    1987-01-01

    Selective chemoaffinity ligands to aid in identification and purification of opioid receptor subtypes were prepared from 6..cap alpha..- and 6..beta..-naltrexol, obtained stereoselectively from the ..mu..-receptor antagonist naltrexone. The targets were the 6..cap alpha..- and 6..beta..-methacrylate ethers and 6..cap alpha..- and 6..beta..-methacrylate esters prepared from reaction of 6..cap alpha..- and 6..beta..-naltrexol with methyl ..cap alpha..-(bromomethyl)acrylate or methacryloyl chloride. Of three methacrylate derivatives, the 6..cap alpha..-ether was the most potent in an opioid receptor binding assay with (/sup 3/H)-naltrexone. In the presence of sodium ion, preincubation of the 6..cap alpha..-ether resulted in recovery of about 60% of original (/sup 3/H)-naltrexone binding suggesting some irreversible effects. The methacrylate esters precipitated withdrawal in morphine dependent monkeys. The enantiomers of verapamil, a calcium channel antagonist, have different pharmacological and pharmacokinetic properties. The oxidative metabolism of verapamil was studied in rat and human liver microsomes and in man after a single oral dose.

  5. Preliminary Screening -- Technical and Economic Assessment of Synthesis Gas to Fuels and Chemicals with Emphasis on the Potential for Biomass-Derived Syngas

    SciTech Connect

    Spath, P. L.; Dayton, D. C.

    2003-12-01

    In principle, syngas (primarily consisting of CO and H2) can be produced from any hydrocarbon feedstock, including: natural gas, naphtha, residual oil, petroleum coke, coal, and biomass. The lowest cost routes for syngas production, however, are based on natural gas, the cheapest option being remote or stranded reserves. Economic considerations dictate that the current production of liquid fuels from syngas translates into the use of natural gas as the hydrocarbon source. Nevertheless, the syngas production operation in a gas-to-liquids plant amounts to greater than half of the capital cost of the plant. The choice of technology for syngas production also depends on the scale of the synthesis operation. Syngas production from solid fuels can require an even greater capital investment with the addition of feedstock handling and more complex syngas purification operations. The greatest impact on improving the economics of gas-to liquids plants is through (1) decreasing capital costs associated with syngas production and (2) improving the thermal efficiency with better heat integration and utilization. Improved thermal efficiency can be obtained by combining the gas-to-liquids plant with a power generation plant to take advantage of the availability of low-pressure steam. The extensive research and development efforts devoted to syngas conversion to fuels and chemicals are documented in a vast amount of literature that tracks the scientific and technological advancements in syngas chemistry. The purpose of this report is to review the many syngas to products processes and summarize the salient points regarding the technology status and description, chemistry, catalysts, reactors, gas cleanliness requirements, process and environmental performances, and economics. Table 1 lists the products examined in this study and gives some facts about the technology as well as advantages and disadvantages. Table 2 summarizes the catalysts, process conditions, conversions, and selectivities for the various syngas to products processes. Table 3 presents catalyst poisons for the various products.

  6. Optimization of water treatment methods for the purification of peat extraction derived runoff: Evaluation of chemical treatment response to variations in incoming water quality using a 2k factorial test design

    NASA Astrophysics Data System (ADS)

    Heiderscheidt, Elisangela; Ronkanen, Anna-Kaisa; Klöve, Björn

    2013-04-01

    The sustainable use of peatland areas requires measures to minimize and when possible eradicate the identified environmental impacts. The drainage of peatlands and other peat extraction, agriculture and forestry activities are known to increase the leaching of pollutant substances resulting in the eutrophication and siltation of receiving water bodies, causing water quality deterioration. Due to the geochemistry characteristics of peat soils the quality of peatland derived runoff water is known to oscillate with location and also with variations in runoff and peak discharge occurrences. Affordable, simple and reliable purification methods that can purify waters rich in particulates, nutrients and dissolved organic carbon while capable of coping with incoming water quality variations are therefore required. Chemical treatment is considered one of the best available technologies for the purification of peat extraction runoff water in Finland; however, until recently little research had been applied on the development of this treatment method for the purification of non-point source pollution. Chemical purification, using metal salts as coagulant agents, is currently applied in several treatment facilities in Finnish peat extraction sites. Nevertheless, variations in runoff water quality and the lack of development of field process parameters has led to the application of high chemical dosages, significant and undesirable fluctuations in purification efficiency and high metal concentration in the discharging waters. This work aims to develop and optimize the chemical purification method by using high level scientific methods to evaluate the response of the purification process to variations in water quality which are typical of peatland derived runoff. The evaluation of how the purification process responds to these variations is a critical step which will enable the development of preventive measures and optimization of relevant process parameters and thus reduce the environmental impacts related to this treatment method. The influence of variations in water quality parameters was accessed using a 2k factorial test design and a well-known chemical purification pilot test procedure (jar test). The k factors or parameters evaluated were: organic matter as chemical oxygen demand (COD 20mg/l and 80mg/l), suspended solids (SS 10mg/l and 60 mg/l), applied coagulant dosage (ferric sulphate 35mg/l and 100mg/l) as well as pH (4.5 and 7.0). Water samples were collected from different peat extraction sites and suitable samples were manipulated using techniques such as centrifugation, dilution and acid or base addition to produce samples with the combinations of high and low concentrations presented. The complete statistical analysis of obtained results will include evaluation of variability using the univariate repeated measures ANOVA as well as the multivariate repeated measures ANOVA methods. Preliminary results of the univariate analyses shows that the interaction between the concentration of a particular substance (COD, SS and pH) and the dosage applied impose significant higher influence on the overall purification efficiency than the substance concentration and applied dosage as individual factors.

  7. A method for simple identification of signature peptides derived from polyUb-K48 and K63 by MALDI-TOF MS and chemically assisted MS/MS fragmentation.

    PubMed

    Døskeland, A P

    2006-02-01

    A simple method is described to identify signature peptides derived from polyubiquitin (polyUb) chains. The method is based on MALDI-TOF MS/MS analysis after chemically assisted fragmentation, and works on peptides isolated from polyacrylamide gels. PolyUb chains branched at K48 and K63 were chosen as models for Ub-protein conjugates. They were resolved by SDS-PAGE, and their tryptic peptides (in-gel-trypsinolysis) derivatized with 3-sulfopropinic acid NHSester to obtain chemically assisted fragmentation during the MS/MS analysis. PolyUb-K63 produced a single peptide identified as (55)TLSDYNIQK(63) (GG)ESTLHLVLR(72). PolyUb-K48 produced two branched signature peptides identified as (43)LIFAGK(48)(GG)QLEDGR(54) and (43)LIFAGK(48)(LRGG)QLEDGR(54). The recovery of signature peptide with LRGG as branched chain underscores the need to take limited proteolysis into account in the search for detection of ubiquitinated peptides in proteomics studies. In conclusion, a simple method has been described allowing the identification of signature peptides, which are diagnostic markers of the majority of polyUb-conjugated proteins. In principle, the method should be applicable also for other more rare signature peptides. PMID:16044192

  8. Growth model and the effect of CuO nanocrystallites on the properties of chemically derived epitaxial thin films of YBa2Cu3O7-x

    NASA Astrophysics Data System (ADS)

    Araki, Takeshi; Niwa, Toshiharu; Yamada, Yutaka; Hirabayashi, Izumi; Shibata, Junko; Ikuhara, Yuichi; Kato, Kazumi; Kato, Takeharu; Hirayama, Tsukasa

    2002-09-01

    In metalorganic deposition using trifluoroacetates (TFA-MOD), CuO nanocrystallites in calcined film, which influence the critical current density (Jc) of the resulting film, have seldom been considered before. CuO nanocrystallites ripen and grow during the calcining process at 200-250 degC and grow into large CuO grains in the YBa2Cu3O7-x (YBCO) film. The final diameter of the grains is about 0.1 mum. When highly purified coating solution is used, suppressing the creation of nanocrystallites in the precursor film is an effective way to obtain high-Jc YBCO film because the nanocrystallites consist only of CuO. We obtained the highest-Jc YBCO film on LaAlO3 single crystal with a calcining process of 9h43m at 200-250 degC. It was 141 nm thick and had a Jc of 7.5 MA/cm2 (77 K, 0 T), as measured by the four-probe method. The firing process of TFA-MOD still has several unsolved problems; why can H2O and HF gas diffuse quickly within the film? These phenomena can be explained by a model with a quasiliquid consisting of Y, Ba, Cu, O, H, and F. The H2O and HF can move quickly in the quasiliquid network within the film during the firing process. According to the model, we can get more conversion of CuO nanocrystallites into quasiliquid by increasing the amount of water vapor. Jc of the film was increased from 3.3 to 4.5 MA/cm2 (77 K, 0 T) by increasing the humidity from 4.2% to 12.1% during the long calcining profile of 66h40m at 200-250 degC. These results confirm the above model. CuO nanocrystallites in precursor films induce nonstoichiometric metal contents in the quasiliquid. Isolated CuO grains in YBCO film indirectly cause nonstoichiometric quasiliquid in other areas. Such nonstoichiometric quasiliquid leads to non-YBCO materials such as BaO, Y2O3, and Y2Cu2O5. Thus, films derived from non-highly purified coating solution and ones prepared with an inappropriate calcining process both have lower Jc values. Micrographs obtained by transmission electron microscopy and Jc results support this hypothesis.

  9. Age and flow pattern of groundwater in a Jurassic limestone aquifer and related Tertiary sands derived from combined isotope, noble gas and chemical data

    NASA Astrophysics Data System (ADS)

    Zuber, A.; Weise, S. M.; Motyka, J.; Osenbrück, K.; Ró?a?ski, K.

    2004-01-01

    Multi-tracer study of the Malm (Upper Jurassic) limestone aquifer in north-western part of Cracow, Poland, revealed the existence of much older waters than those estimated from Darcy's law. The following environmental tracers were used: 3H, 14C, ?13C, ?18O, ?2H, 4He, Ne, Ar, Kr, Xe, 3He/ 4He and 40Ar/ 36Ar in combination with water chemistry. The natural drainage of unconfined parts of the aquifer is by springs and streams, with a dominant presence of modern and pre-bomb era Holocene waters, whereas the confined part is drained only by upward leakage through thick Miocene clays in river valleys, mainly in the Vistula (Wis?a) river valley. As a consequence, the confined part contains much older waters. Their glacial ages are indicated by ?18O and ?2H values significantly more negative than those found for modern recharge and by noble gas temperatures reduced by ca. 4.5 °C when compared to the present-day mean annual air temperatures. Quantitative age interpretation of 14C is regarded unreliable due to isotope exchange between dissolved and solid carbonates as suggested by ?13C values of DIC in the range of -0.6 to -6.1‰ for the confined part of the aquifer. Similarly, quantitative 4He dating turned out to be unreliable, though 4He excess values (0.93-5.45×10 -6 cm 3 STP/g) and very low 14C contents (0.0-5.5 pmc) suggest glacial ages. Changes in hydrochemistry also indicate a long-lasting water-rock interaction probably dominated by diffusion-controlled exchange with overlying and underlying formations. Admixture of older water ascending from underlying formations is observed at two sites. That older water is also supposed to be of Quaternary age as the 40Ar/ 36Ar of the mixture remains equal to the atmospheric ratio. Great tracer ages are shown to result mainly from the delay of solute velocity with respect to the velocity of mobile water, caused by diffusive exchange between mobile water in the fissures (porosity of 0.0001-0.001) and stagnant water in the matrix (porosity of ˜0.06). This stagnant water in the porous matrix is the main water reservoir in the Malm aquifer. In the erosion structures of the Malm limestones, close to the Cracow centre on the southern side of the Vistula river, Tertiary sands are deposited under clay cover. Prior to this study, the origin and age of mineral water exploited from these sands was controversial. However, tracer data indicated meteoric water recharged at the end of the last glacial, and excluded an admixture of connate marine water from adjacent formations. In one well a 10% admixture of modern water was observed with the mean age of about 30 years as determined from the lumped-parameter modelling of the tritium data. The recharge is supposed to take place indirectly through nearby Malm horsts and/or by seepage through Miocene clays in unidentified areas, with dissolution of evaporites as the main source of chemical components. The glacial ages of waters in the confined parts of the Malm aquifer and in Tertiary sands indicate their low vulnerability to anthropogenic pollution.

  10. 40 CFR 721.10328 - Salt of polyalkylenepolyamine derivative (generic).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...2012-07-01 2012-07-01 false Salt of polyalkylenepolyamine derivative (generic...Specific Chemical Substances § 721.10328 Salt of polyalkylenepolyamine derivative (generic...chemical substance identified generically as salt of polyalkylenepolyamine...

  11. 40 CFR 721.10328 - Salt of polyalkylenepolyamine derivative (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...2013-07-01 2013-07-01 false Salt of polyalkylenepolyamine derivative (generic...Specific Chemical Substances § 721.10328 Salt of polyalkylenepolyamine derivative (generic...chemical substance identified generically as salt of polyalkylenepolyamine...

  12. The Amazingly Versatile Titanocene Derivatives

    NASA Astrophysics Data System (ADS)

    Bowman, Donald C.

    2006-05-01

    Derivatives of titanocene are remarkably versatile in their chemical applications. This article presents a brief review of the derivatives' uses in the fields of polymers, medical oncology, and organic synthesis. While exhaustive studies exist emphasizing a single field of application, this article shows the breadth of application existing with these complexes.

  13. Chemical Peels

    MedlinePLUS

    ... to Choose the Best Skin Care Products Chemical Peels Uses for Chemical Peels Learn more about specific conditions where chemical peels ... skin Sagging skin Wrinkles What is a chemical peel? A chemical peel is a technique used to ...

  14. Hemoglobin derivatives

    MedlinePLUS

    ... in red blood cells that moves oxygen and carbon dioxide between the lungs and body tissues. This ... This test is used to diagnose carbon monoxide poisoning . It is ... that may result from certain drugs. Some chemicals or drugs can ...

  15. Chemical fixation of sewage sludge derived ash

    Microsoft Academic Search

    Farhana Mohamed; I. Y. Sam Cheng; Ruey S. Huang; Evelyn C. Santos

    1991-01-01

    Los Angeles processes sewage sludge by dehydration and combustion at its Hyperion Treatment Plant. The ash product is usually classified as hazardous because of its heavy metal content, and four readily?available fixing agents have been evaluated for possible use as stabilizers. The ash leachability was assessed before and after fixation using the California Waste Extraction Test. The leaching characteristics of

  16. Chemical Changes

    NSDL National Science Digital Library

    Mr. Jolley

    2005-10-25

    In this activity you will learn what a chemical change is. The first step to understanding chemical changes is to recognize the difference between chemical properties and physical properties. Click here for an example: Chemical and Physical Changes What are the signs of a chemical reaction occuring? Signs of Chemical Change What variables affect a chemical reaction? Variables ...

  17. Radical-assisted chemical doping for chemically derived graphene

    PubMed Central

    2013-01-01

    Carrier doping of graphene is one of the most challenging issues that needs to be solved to enable its use in various applications. We developed a carrier doping method using radical-assisted conjugated organic molecules in the liquid phase and demonstrated all-wet fabrication process of doped graphene films without any vacuum process. Charge transfer interaction between graphene and dopant molecules was directly investigated by spectroscopic studies. The resistivity of the doped graphene films was drastically decreased by two orders of magnitude. The resistivity was improved by not only carrier doping but the improvement in adhesion of doped graphene flakes. First-principles calculation supported the model of our doping mechanism. PMID:24355062

  18. Chemical Peels

    MedlinePLUS

    ... Diseases and treatments A - D Chemical peel Chemical peels Also called chemexfoliation , derma peeling Do you wish ... cost of cosmetic treatments. Learn more about chemical peels: Is a chemical peel the right choice for ...

  19. Chemical Mechanical Planarization- Chemical

    NSDL National Science Digital Library

    This website includes an animation which illustrates the chemical action of slurry in the chemical-mechanical planarization process. Objective: Explain the mechanical and chemical steps in the CMP process. This simulation is from Module 068 of the Process & Equipment III Cluster of the MATEC Module Library (MML). Find this animation under the section "Process & Equipment III." To view other clusters or for more information about the MML visit http://matec.org/ps/library3/process_I.shtmlKey Phrase: MATEC Animation

  20. Semisynthetic Derivatives of Epothilones

    NASA Astrophysics Data System (ADS)

    Altmann, Karl-Heinz

    Semisynthetic derivatives of natural products traditionally occupy a prominent space in natural-product-based drug discovery (1, 2). As many biologically active natural products exhibit a high degree of structural complexity (3), the chemical derivatization of material isolated from natural sources often represents the only feasible means (or at least the only economically viable approach) to explore structure-activity-relationships (SAR) and to produce analogs with more favorable pharmacokinetic and pharmacological properties than the natural product lead. Examples of clinically important drugs that are semisynthetic derivatives of natural products exist in virtually all disease areas (1, 2); in the treatment of cancer this includes compounds such as etoposide or teniposide (derived from podophyllotoxin) (4-6), irinotecan and topotecan (derived from camptothecin) (7-9), or docetaxel (derived from 10-deacetylbaccatin III) (10, 11). Even for taxol (11), which is a natural product (12), the sustained supply of sufficient quantities of material for widespread clinical use could only be secured through the development of a semisynthetic production process from another natural product, namely, 10-deacetylbaccatin III (13). In light of these facts, it is not surprising that semisynthesis approaches have also featured prominently in the elucidation of the SAR for epothilones and in the discovery of a number of clinical development candidates.

  1. Complex derivatives

    NASA Astrophysics Data System (ADS)

    Battiston, Stefano; Caldarelli, Guido; Georg, Co-Pierre; May, Robert; Stiglitz, Joseph

    2013-03-01

    The intrinsic complexity of the financial derivatives market has emerged as both an incentive to engage in it, and a key source of its inherent instability. Regulators now faced with the challenge of taming this beast may find inspiration in the budding science of complex systems.

  2. LLNL Chemical Kinetics Modeling Group

    SciTech Connect

    Pitz, W J; Westbrook, C K; Mehl, M; Herbinet, O; Curran, H J; Silke, E J

    2008-09-24

    The LLNL chemical kinetics modeling group has been responsible for much progress in the development of chemical kinetic models for practical fuels. The group began its work in the early 1970s, developing chemical kinetic models for methane, ethane, ethanol and halogenated inhibitors. Most recently, it has been developing chemical kinetic models for large n-alkanes, cycloalkanes, hexenes, and large methyl esters. These component models are needed to represent gasoline, diesel, jet, and oil-sand-derived fuels.

  3. Visualizing chemical reactions and crossover processes in a fuel cell inserted in the ESR resonator: detection by spin trapping of oxygen radicals, nafion-derived fragments, and hydrogen and deuterium atoms.

    PubMed

    Danilczuk, Marek; Coms, Frank D; Schlick, Shulamith

    2009-06-11

    We present experiments in an in situ fuel cell (FC) inserted in the resonator of the ESR spectrometer that offered the ability to observe separately processes at anode and cathode sides and to monitor the formation of HO and HOO radicals, H and D atoms, and radical fragments derived from the Nafion membrane. The presence of the radicals was determined by spin-trapping electron spin resonance (ESR) with 5,5-dimethylpyrroline N-oxide (DMPO) as a spin trap. The in situ FC was operated at 300 K with a membrane-electrode assembly (MEA) based on Nafion 117 and Pt as catalyst, at closed and open circuit voltage conditions, CCV and OCV, respectively. Experiments with H(2) or D(2) at the anode and O(2) at the cathode were performed. The DMPO/OH adduct was detected only at the cathode for CCV operation, suggesting generation of hydroxyl radicals from H(2)O(2) formed electrochemically via the two-electron reduction of oxygen. The DMPO/OOH adduct, detected in this study for the first time in a FC, appeared at the cathode and anode for OCV operation, and at the cathode after CCV FC operation of >or=2 h. These results were interpreted in terms of electrochemical generation of HOO at the cathode (HO + H(2)O(2) --> H(2)O + HOO) and its chemical generation at the anode from hydrogen atoms and crossover oxygen (H + O(2) --> HOO). DMPO/H and DMPO/D adducts were detected at the anode and cathode sides, for CCV and OCV operation; H and D are aggressive radicals capable of abstracting fluorine from the tertiary carbon in the polymer membrane chain and of leading to chain fragmentation. Carbon-centered radical (CCR) adducts were detected at the cathode after CCV FC operation; weak CCR signals were also detected at the anode. CCRs can originate only from the Nafion membranes, and their presence indicates membrane fragmentation. Taken together, this study has demonstrated that FC operation involves processes such as gas crossover, reactions at the catalyst surface, and possible attack of the membrane by reactive H or D that do not occur in ex situ experiments in the laboratory, thus implying different mechanistic pathways in the two types of experiments. PMID:19453175

  4. Chemical Emergencies

    MedlinePLUS

    ... the case of a terrorist attack with a chemical weapon. Some hazardous chemicals have been developed by military ... there are no guarantees of safety during a chemical emergency, you can take actions to protect yourself. You ...

  5. An Elementary Discussion of Chemical Equilibrium.

    ERIC Educational Resources Information Center

    David, Carl W.

    1988-01-01

    This discussion uses a more difficult reaction as the prototype to derive the standard equation for chemical equilibrium. It can be used by students who can understand and use partial derivatives. (CW)

  6. Chemical Specific Adjustment factors Workshop

    EPA Science Inventory

    The World Health Organization, through the International Programme on Chemical Safety (IPCS), has established guidance on the use of mechanistic data to replace default uncertainty factors for interspecies extrapolation and intraspecies variability in deriving risk values such as...

  7. Reduction behavior induced by HL010183, a metformin derivative against the growth of cutaneous squamous cell carcinoma

    PubMed Central

    Miao, Guoying; Liu, Baoguo; Guo, Xiaohui; Zhang, Xike; Liu, Gui-jing

    2015-01-01

    Metformin is a biguanide widely prescribed as a first-line antidiabetic drug in type 2 diabetes mellitus patients. Animal and cellular studies support that metformin has a strong anti-proliferative effect on various cancers. Herein, we report that metformin derivative, HL010183 significantly inhibited human epidermoid A431 tumor xenograft growth in nu/nu mice, which in turn is associated with a significant reduction in proliferative biomarkers PCNA and cyclins D1/B1. Enhanced apoptotic cell death and an increase in Bax: Bcl2 ratio supported the tumor growth reduction. The mechanism of the drug effects appears to be dependent on the inhibition of nuclear factor kappa B (NFkB) and mTOR signaling pathways. Reduced enhancement of NFkB transcriptional target proteins, iNOS/COX-2 together with decreased phosphorylation of NFkB inhibitory protein IKBa were also observed. Further, AKT signaling activation was evaluated by the reduced phosphorylation at Ser473. In addition, a concomitant decrease in mTOR signaling pathway was also estimated from the reduced phosphorylation at mTOR regulatory proteins p70S6K and 4E-BP-1. Along with this, decreased phosphorylation of GSK3b, which is carried out by AKT kinases was also observed. Overall results suggested that HL010183 interrupt SCC growth via NFkB and mTOR signaling pathways. PMID:25755715

  8. New poly(ester urea) derived from L-leucine: electrospun scaffolds loaded with antibacterial drugs and enzymes.

    PubMed

    Díaz, Angélica; del Valle, Luis J; Tugushi, David; Katsarava, Ramaz; Puiggalí, Jordi

    2015-01-01

    Electrospun scaffolds from an amino acid containing poly(ester urea) (PEU) were developed as promising materials in the biomedical field and specifically in tissue engineering applications. The selected poly(ester urea) was obtained with a high yield and molecular weight by reaction of phosgene with a bis(?-aminoacyl)-?,?-diol-diester monomer. The polymer having L-leucine, 1,6-hexanediol and carbonic acid units had a semicrystalline character and relatively high glass transition and melting temperatures. Furthermore it was highly soluble in most organic solvents, an interesting feature that facilitated the electrospinning process and the effective incorporation of drugs with bactericidal activity (e.g. biguanide derivatives such as clorhexidine and polyhexamethylenebiguanide) and enzymes (e.g. ?-chymotrypsin) that accelerated the degradation process. Continuous micro/nanofibers were obtained under a wide range of processing conditions, being diameters of electrospun fibers dependent on the drug and solvent used. Poly(ester urea) samples were degradable in media containing lipases and proteinases but the degradation rate was highly dependent on the surface area, being specifically greater for scaffolds with respect to films. The high hydrophobicity of new scaffolds had repercussions on enzymatic degradability since different weight loss rates were found depending on how samples were exposed to the medium (e.g. forced or non-forced immersion). New scaffolds were biocompatible, as demonstrated by adhesion and proliferation assays performed with fibroblast and epithelial cells. PMID:25492010

  9. Dihydrochalcones and phenanthrene derivatives from Fissistigma bracteolatum

    Microsoft Academic Search

    Zhu Hongping; Lu Xiaoling; Sun Xiaohong; Xu Qiangzhi; Jiao Binghua

    2010-01-01

    Three dihydrochalcones derivatives 1-3, flavone 4 and phenanthrene derivative 5 were isolated, together with 9 known compounds, from the air-dried root bark of Fissistigma bracteolatum Chatterjee. Their structures were determined by spectroscopic (NMR, MS) and chemical methodologies.

  10. Chemical Communication

    NSDL National Science Digital Library

    0000-00-00

    A concise lesson about chemical communication in insects covering both semio and info chemicals. The site includes a short video of grape root borer moths using sex pheromone. Further links on the take the user to visual and auditory communication.

  11. Chemical sensor

    NASA Technical Reports Server (NTRS)

    Rauh, R. David (Inventor)

    1990-01-01

    A sensor for detecting a chemical substance includes an insertion element having a structure which enables insertion of the chemical substance with a resulting change in the bulk electrical characteristics of the insertion element under conditions sufficient to permit effective insertion; the change in the bulk electrical characteristics of the insertion element is detected as an indication of the presence of the chemical substance.

  12. Synthesis and characterization of lithium molybdenum selenide nanowires for chemical sensing applications and of nanosheets derived from potassium tetratitanate, potassium calcium niobate, and potassium niobate for photocatalytic water splitting

    NASA Astrophysics Data System (ADS)

    Allen, Mark Ryan

    This work describes both the fabrication of LiMo3Se3 nanowire films and assessment their ability to detect analytes in aqueous solution, and the construction of layered photocatalysts, including heterojunction multicomponent materials, from K2Ti4O9, KCa 2Nb3O10, and K4Nb6O 17 nanosheets, and the characterization of these for their photocatalytic water splitting properties. The LiMo3Se3 nanowire film sensors were conceived by drop-coating a 0.05% (mass) aqueous nanowire solution onto microfabricated indium tin oxide electrode pairs. According to scanning electron microscopy (SEM) and atomic force microscopy (AFM), the films are made of a dense network of 3-7 nm thick nanowire bundles. Immersion of the films in 1.0 M aqueous solutions of group 1 or 2 metal halides or of Zn(II), Mn(II), Fe(II), or Co(II) chlorides results in an increase of the electrical resistance of the films. The resistance change is always positive and reaches up to 9% of the base resistance of the films. It occurs over the course of 30-240 s, and it is reversible for monovalent ions and partially reversible for divalent ions. The signal depends on the concentration of the electrolyte and on the size and charge of the metal cation. Anions do not play a significant role, presumably because they are repelled by the negatively charged nanowire strands. The magnitude of the electrical response and its sign suggest that it is due to analyte-induced scattering of conduction electrons in the nanowires. An ion-induced field effect can be excluded based on gated conductance measurements of the nanowire films. The tetratitanate K2Ti4O9 has been known as a photocatalyst for the oxidation of methanol under UV irradiation. Here we study the evolution of the morphological, optical, and photocatalytic properties of this titanate as it is converted into H2Ti4O 9 and subsequently exfoliated into individual tetrabutylammonium (TBA)-supported [Ti4O9]-2 nanosheets. We find that proton exchange and exfoliation are accompanied by a red shift of the optical absorption edge and fluorescence maximum, suggesting a reduction of the bandgap in the series K2Ti4O9 (3.54 eV), H2Ti 4O9 (3.25 eV), (TBA)2[Ti4O9] (3.00 eV). Neither compound is active for photochemical water splitting, even after photochemical deposition of platinum nanoparticles. However, in aqueous methanol, all platinated compounds are moderately active for H2 evolution upon bandgap irradiation, and in 0.01 M AgNO3, they all produce moderate quantities of O2. From the onset potentials for photoelectrochemical methanol oxidation, the values for the valence band edges at pH 7 are deduced to be lie between -0.23 and -0.53 V (NHE) for the non-platinated compounds, and at +0.08 V and -0.30 V for the platinated compounds. This Pt-induced decrease of negative charge on the titanates is likely due to Fermi level equilibration of metal and semiconductor. Its effect can also be seen in a shift of the onset potentials for electrochemical water oxidation, as measured by cyclic voltammetry. Transient absorption data reveal that photogenerated electrons are trapped in mid band gap states, from which they decay exponentially with a time-constant of 43.67 +/- 0.28 ms, much slower than observed for 68 +/- 1 ns for TiO2 nanocrystals (Degussa, P25). Heterojunction multicomponent photocatalysts have been shown to possess enhanced charge separation upon photoexcitation. Nanostructured heterojunctions were prepared through soft chemical routes from nanosheets derived from the parent vi compounds K2Ti4O9, KCa2Nb 3O10, and K4Nb6O17. Five composites in total, consisting of either one or two types of nanosheets, were synthesized by precipitation of the precursor nanosheets with KOH. Resultant stacked materials were confirmed with transmission electron microscopy and characterized via powder x-ray diffraction. The layered catalysts were found to be inactive for photocatalytic water splitting under illumination of ultraviolet light. However, when irradiated in aqueous methanol, all five materials did yield substantial amounts of H2 gas. Photochem

  13. 40 CFR 721.10045 - Diazotized substituted heteromonocycle coupled with naphthalene sulfonic acid derivative, nickel...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...acid derivative, nickel complex, alkaline salt (generic). 721.10045 Section 721...acid derivative, nickel complex, alkaline salt (generic). (a) Chemical substance...derivative, nickel complex, alkaline salt (PMN P-02-737) is subject to...

  14. Chemical burns

    PubMed Central

    Cartotto, Robert C.; Peters, Walter J.; Neligan, Peter C.; Douglas, Leith G.; Beeston, Jeff

    1996-01-01

    Objectives To report a burn unit’s experience with chemical burns and to discuss the fundamental principles in managing chemical burns. Design A chart review. Setting A burn centre at a major university-affiliated hospital. Patients Twenty-four patients with chemical burns, representing 2.6% of all burn admissions over an 8-year period at the Ross Tilley Regional Adult Burn Centre. Seventy-five percent of the burn injuries were work-related accidents. Chemicals involved included hydrofluoric acid, sulfuric acid, black liquor, various lyes, potassium permanganate and phenol. Results Fourteen patients required excision and skin grafting. Complications were frequent and included ocular chemical contacts, wound infections, tendon exposures, toe amputation and systemic reactions from absorption of chemical. One patient died from a chemical scald burn to 98% of the body surface area. Conclusions The key principles in the management of chemical burns include removal of the chemical, copious irrigation, limited use of antidotes, correct estimation of the extent of injury, identification of systemic toxicity, treatment of ocular contacts and management of chemical inhalation injury. Individualized treatment is emphasized. PMID:8640619

  15. Chemical Composition

    NASA Astrophysics Data System (ADS)

    May, Willie; Cavanagh, Richard; Turk, Gregory; Winchester, Michael; Travis, John; Smith, Melody; Derose, Paul; Choquette, Steven; Kramer, Gary; Sieber, John; Greenberg, Robert; Lindstrom, Richard; Lamaze, George; Zeisler, Rolf; Schantz, Michele; Sander, Lane; Phinney, Karen; Welch, Michael; Vetter, Thomas; Pratt, Kenneth; Scott, John; Small, John; Wight, Scott; Stranick, Stephan

    Measurements of the chemical compositions of materials and the levels of certain substances in them are vital when assessing and improving public health, safety and the environment, are necessary to ensure trade equity, and are required when monitoring and improving industrial products and services. Chemical measurements play a crucial role in most areas of the economy, including healthcare, food and nutrition, agriculture, environmental technologies, chemicals and materials, instrumentation, electronics, forensics, energy, and transportation.

  16. Chemical Bonds

    NSDL National Science Digital Library

    The Concord Consortium

    2011-12-11

    Electrons are key to forming the two broad categories of chemical bonds: covalent and ionic. Atoms, which have a nucleus surrounded by electrons, are represented in several different ways. In the Chemical Bonds activity, students explore the different kinds of chemical bonds that can form, ranging from non-polar covalent to ionic. In the model depicted above students adjust the electronegativity of two atoms and see the effect it has on electron distribution and bond type.

  17. Heterogeneous nature of the pre-subduction mantle wedge and their transformation to pyroxene-rich lithologies by slab-derived chemical agents: Tepic-Zacoalco rift, western Trans-Mexican Volcanic Belt

    NASA Astrophysics Data System (ADS)

    Díaz Bravo, B. A.; Gomez-Tuena, A.; Ortega-Obregón, C.; Perez-Arvizu, O.

    2013-12-01

    Alkaline basalts with geochemical features similar to those of intraplate Ocean Islands have been emplaced along the main trace of the Tepic-Zacoalco rift (TZR) in western Mexico. Comprehensive geochemical and petrologic data on volcanic rocks along the rift indicates that the pre-subduction background mantle wedge in western Mexico is as heterogeneous as that below the Pacific basin, and includes a recycled, high-? component (HIMU; ? =238U/204Pb) in their mantle source. Olivines contained within these samples have NiO and CaO contents similar to olivines from MORB, suggesting that the source of enrichment must be entirely hosted in peridotite. More evolved rocks within the TZR have a stronger subduction signatures and water contents, and display a distinctive Pb isotopic array that suggest slab additions. Olivine phenocrysts from these rocks have lower Fo but extend higher NiO and lower CaO contents than those from more mafic magmas, suggesting derivation from a secondary pyroxenite source. It thus appears that the heterogeneous nature of the pristine pre-subduction mantle wedge in western Mexico can only be sampled when extension-driven mantle upwelling induces low extents of melting of a dry peridotitic mantle that preferentially sample its most enriched and easily fusible components. Yet even a small amount of slab-derived silica promotes a secondary petrologic transformation to pyroxene-rich lithologies that upon remelting create magmas with compositions that are similar to arc volcanoes. Metasomatic silica addition is ultimately related to the convergent margin, but deep subduction of Rivera plate below the TZR preclude a direct derivation from the slab surface. The participation of hybrid subduction mélanges that detach from the downgoing slab and melt in the hot core of the mantle wedge can provide a viable alternative explanation.

  18. Chemical Composition

    Microsoft Academic Search

    Willie May; Richard Cavanagh; Gregory Turk; Michael Winchester; John Travis; Melody Smith; Paul Derose; Steven Choquette; Gary Kramer; John Sieber; Robert Greenberg; Richard Lindstrom; George Lamaze; Rolf Zeisler; Michele Schantz; Karen Phinney; Michael Welch; Thomas Vetter; Kenneth Pratt; John Scott; John Small; Scott Wight; Stephan Stranick

    2006-01-01

    Measurements of the chemical compositions of materials and the levels of certain substances in them are vital when assessing and improving public health, safety and the environment, are necessary to ensure trade equity, and are required when monitoring and improving industrial products and services. Chemical measurements play a crucial role in most areas of the economy, including healthcare, food and

  19. Chemical geodynamics

    Microsoft Academic Search

    A. Zindler; S. R. Hart

    1986-01-01

    Consideration is given to the following three principal boundary conditions relating to the nature and development of chemical structure in the earth's mantle: (1) inferred scale lengths for mantle chemical heterogeneities, (2) interrelationships of the various isotopic tracers, and (3) the bulk composition of the earth. These boundary conditions are integrated with geophysical constraints in order to evaluate models for

  20. Chemical Reactions

    NSDL National Science Digital Library

    National Science Teachers Association (NSTA)

    2009-05-01

    We don't often stop to think about it, but underlying many of our everyday activities are chemical reactions. From the cooking of an egg to the growth of a child, chemical reactions make things happen. Although many of the reactions that support our lives

  1. Thermodynamic Derivation of the Equilibrium Distribution Functions of Statistical Mechanics.

    ERIC Educational Resources Information Center

    Stoeckly, Beth

    1979-01-01

    Presents a simplified derivation of the equilibrium distribution functions. The derivation proceeds from the change in the Helmholtz free energy when a particle is added to a system of fixed temperature, volume, and chemical potential. The derivations show the relationship between statistical mechanics and macroscopic thermodynamics. (Author/GA)

  2. Magnetoelectric coupling in La0.6Ca0.4MnO3-Bi0.6Nd0.4TiO3 composite thin films derived by a chemical solution deposition method

    NASA Astrophysics Data System (ADS)

    Cheng, C. P.; Tang, M. H.; Lv, X. S.; Tang, Z. H.; Xiao, Y. G.

    2012-11-01

    Magnetoelectric (ME) xLa0.6Ca0.4MnO3-(1-x)Bi0.6Nd0.4TiO3 composite thin films with x = 0.3, 0.4, and 0.5 were fabricated on Pt/Ti/SiO2/Si(100) substrates by a chemical solution deposition method. The well-defined ferroelectric loops are observed. The Pr values are 11.2, 12.8, and 13.9 ?C/cm2 under the condition of about 350 kV/cm electric field for the composite films with x = 0.3, 0.4, and 0.5. The composite films exhibit typical magnetic hysteresis loops, as well as remnant magnetizations. ME effect which is dependent on Hbias is observed. The results show that the films exhibit both good ferroelectric and magnetic properties, as well as a ME effect.

  3. CHEMICALS INCORPORATED IN NEST MATERIAL BY RED IMPORTED FIRE ANTS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Red imported fire ants are believed to incorporate ant-derived chemicals in nesting material. However, only a few chemicals have been identified. One hurdle for such investigation is the interference in chemical analysis from soil-borne chemicals. Ants were found to be able to construct their nes...

  4. The use of enzymes in the chemical industry in Europe

    Microsoft Academic Search

    Andreas Schmid; Frank Hollmann; Jin Byung Park; Bruno Bühler

    2002-01-01

    Many European chemical industries are in a phase of reorganization resulting in a general opening towards life sciences. Traditional chemical markets are served increasingly with products derived from bioprocesses or hybrid chemical\\/biocatalytic processes. Biocatalytic steps are already being used to produce a wide range of products, including agricultural chemicals, organics, drugs and plastic materials, to name but a few. Apart

  5. Unnecessary Chemicals

    ERIC Educational Resources Information Center

    Johnson, Anita

    1978-01-01

    Discusses the health hazards resulting from chemical additions of many common products such as cough syrups, food dyes, and cosmetics. Steps being taken to protect consumers from these health hazards are included. (MDR)

  6. Weather Derivative Valuation

    NASA Astrophysics Data System (ADS)

    Jewson, Stephen; Brix, Anders

    2005-04-01

    Weather Derivative Valuation is the first book to cover all the meteorological, statistical, financial and mathematical issues that arise in the pricing and risk management of weather derivatives. There are chapters on meteorological data and data cleaning, the modelling and pricing of single weather derivatives, the modelling and valuation of portfolios, the use of weather and seasonal forecasts in the pricing of weather derivatives, arbitrage pricing for weather derivatives, risk management, and the modelling of temperature, wind and precipitation. Specific issues covered in detail include the analysis of uncertainty in weather derivative pricing, time-series modelling of daily temperatures, the creation and use of probabilistic meteorological forecasts and the derivation of the weather derivative version of the Black-Scholes equation of mathematical finance. Written by consultants who work within the weather derivative industry, this book is packed with practical information and theoretical insight into the world of weather derivative pricing.

  7. 40 CFR 721.10579 - Carbon black derived from the pyrolysis of rubber tire shreds (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...2013-07-01 2013-07-01 false Carbon black derived from the pyrolysis of rubber...Chemical Substances § 721.10579 Carbon black derived from the pyrolysis of rubber...chemical substance identified generically as carbon black derived from the pyrolysis...

  8. 40 CFR 721.10579 - Carbon black derived from the pyrolysis of rubber tire shreds (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...2014-07-01 2014-07-01 false Carbon black derived from the pyrolysis of rubber...Chemical Substances § 721.10579 Carbon black derived from the pyrolysis of rubber...chemical substance identified generically as carbon black derived from the pyrolysis...

  9. 40 CFR 721.558 - Salt of a fatty alkylamine derivative (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...2013-07-01 2013-07-01 false Salt of a fatty alkylamine derivative (generic...Specific Chemical Substances § 721.558 Salt of a fatty alkylamine derivative (generic...chemical substance identified generically as a salt of a fatty alkylamine derivative...

  10. 40 CFR 721.558 - Salt of a fatty alkylamine derivative (generic).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...2012-07-01 2012-07-01 false Salt of a fatty alkylamine derivative (generic...Specific Chemical Substances § 721.558 Salt of a fatty alkylamine derivative (generic...chemical substance identified generically as a salt of a fatty alkylamine derivative...

  11. Acoustic cavitation and its chemical consequences

    E-print Network

    Suslick, Kenneth S.

    Acoustic cavitation and its chemical consequences By Kenneth S. Suslick, Yuri Didenko, Ming M. Fang Acoustic cavitation is responsible for both sonochemistry and sonoluminescence. Bubble collapse in liquids, sonochemistry and sonoluminescence derive principally from acoustic cavitation: the formation, growth

  12. Chemiluminescence of indole and its derivatives

    NASA Astrophysics Data System (ADS)

    Vasil'ev, Rostislav F.; Trofimov, A. V.; Tsaplev, Yuri B.

    2010-02-01

    The results of studies on chemiluminescence of indole and its derivatives are critically analyzed. It is shown that chemical transformations of indoles lead, depending on the structure and experimental conditions, to various electronically excited products and emission of light. Many reactions considered are used as a basis for highly sensitive methods for detection of indoles in biology, medicine, ecology and forensics.

  13. Biofuels and bio-products derived from

    E-print Network

    Ginzel, Matthew

    NEED Biofuels and bio- products derived from lignocellulosic biomass (plant materials) are part improve the energy and carbon efficiencies of biofuels production from a barrel of biomass using chemical and thermal catalytic mechanisms. The Center for Direct Catalytic Conversion of Biomass to Biofuels IMPACT

  14. Chemical sensors

    SciTech Connect

    Hubbard, C.W.; Gordon, R.L.

    1987-05-01

    The revolution in analytical chemistry promised by recent developments in the field of chemical sensors has potential for significant positive impact on both research and production activities conducted by and for the Department of Energy. Analyses which were, in the past, performed only with a roomful of expensive equipment can now be performed with miniature solid-state electronic devices or small optical probes. Progress in the development of chemical sensors has been rapid, and the field is currently growing at a great rate. In accordance, Pacific Northwest Laboratory initiated a survey of recent literature so that contributors to active programs in research on analytical methods could be made aware of principles and applications of this new technology. This report presents the results of that survey. The sensors discussed here are divided into three types: micro solid-state devices, optical sensors, and piezoelectric crystal devices. The report is divided into three corresponding sections. The first section, ''Micro Solid-State Devices,'' discusses the design, operation, and application of electronic sensors that are produced in much the same way as standard solid-state electronic devices. The second section, ''Optrodes,'' covers the design and operation of chemical sensors that use fiber optics to detect chemically induced changes in optical properties. The final section, ''Piezoelectric Crystal Detectors,'' discusses two types of chemical sensors that depend on the changes in the properties of an oscillating piezoelectric crystal to detect the presence of certain materials. Advantages and disadvantages of each type of sensor are summarized in each section.

  15. Can hydroxylamine be a more potent nucleophile for the reactivation of tabun-inhibited AChE than prototype oxime drugs? An answer derived from quantum chemical and steered molecular dynamics studies.

    PubMed

    Lo, Rabindranath; Ganguly, Bishwajit

    2014-07-29

    Organophosphorus nerve agents are highly toxic compounds which strongly inhibit acetylcholinesterase (AChE) in the blood and in the central nervous system (CNS). Tabun is one of the highly toxic organophosphorus (OP) compounds and is resistant to many oxime drugs formulated for the reactivation of AChE. The reactivation mechanism of tabun-conjugated AChE with various drugs has been examined with density functional theory and ab initio quantum chemical calculations. The presence of a lone-pair located on the amidic group resists the nucleophilic attack at the phosphorus center of the tabun-conjugated AChE. We have shown that the newly designed drug candidate N-(pyridin-2-yl)hydroxylamine, at the MP2/6-31+G*//M05-2X/6-31G* level in the aqueous phase with the polarizable continuum solvation model (PCM), is more effective in reactivating the tabun-conjugated AChE than typical oxime drugs. The rate determining activation barrier with N-(pyridin-2-yl)hydroxylamine was found to be ?1.7 kcal mol(-1), which is 7.2 kcal mol(-1) lower than the charged oxime trimedoxime (one of the most efficient reactivators in tabun poisonings). The greater nucleophilicity index (?(-)) and higher CHelpG charge of pyridinylhydroxylamine compared to TMB4 support this observation. Furthermore, we have also examined the reactivation process of tabun-inhibited AChE with some other bis-quaternary oxime drug candidates such as methoxime (MMB4) and obidoxime. The docking analysis suggests that charged bis-quaternary pyridinium oximes have greater binding affinity inside the active-site gorge of AChE compared to the neutral pyridinylhydroxylamine. The peripheral ligand attached to the neutral pyridinylhydroxylamine enhanced the binding with the aromatic residues in the active-site gorge of AChE through effective ?-? interactions. Steered molecular dynamics (SMD) simulations have also been performed with the charged oxime (TMB4) and the neutral hydroxylamine. From protein-drug interaction parameters (rupture force profiles, hydrogen bonds, hydrophobic interactions), geometry and the orientation of the drug candidates, the hydroxylamine is suggested to orchestrate the reactivation process better than TMB4. Furthermore, the calculated log?P values show the effective penetration of the neutral drug candidate through the blood-brain barrier. The toxicity measurements and the IC50 values (a measure of the intrinsic affinity toward AChE) suggest that the pyridinylhydroxylamine compound could have similar toxic behavior compared to the prototype oxime antidotes used for reactivation purposes. The newly designed pyridinylhydroxylamine drug candidate can be an effective antidote both kinetically and structurally to reactivate the tabun-inhibited enzyme. PMID:24964273

  16. The chemical Langevin equation Daniel T. Gillespiea)

    E-print Network

    Mangel, Marc

    The chemical Langevin equation Daniel T. Gillespiea) Research Department, Code 4T4100D, Naval Air master equation is derived leads directly to an approximate time-evolution equation of the Langevin type. This chemical Langevin equation is the same as one studied earlier by Kurtz, in contradistinction to some other

  17. Chemical methods for the production of graphenes

    Microsoft Academic Search

    Sungjin Park; Rodney S. Ruoff

    2009-01-01

    Interest in graphene centres on its excellent mechanical, electrical, thermal and optical properties, its very high specific surface area, and our ability to influence these properties through chemical functionalization. There are a number of methods for generating graphene and chemically modified graphene from graphite and derivatives of graphite, each with different advantages and disadvantages. Here we review the use of

  18. 40 CFR 721.10672 - Sodium olefin sulfonate derivative (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.10672 Sodium olefin sulfonate derivative...substances and significant new uses subject to reporting. ...identified generically as sodium olefin sulfonate...

  19. Derivations of quasi *-algebras

    E-print Network

    F. Bagarello; A. Inoue; C. Trapani

    2009-03-31

    The spatiality of derivations of quasi *-algebras is investigated by means of representation theory. Moreover, in view of physical applications, the spatiality of the limit of a family of spatial derivations is considered.

  20. On the chemical composition of Open Clusters

    NASA Astrophysics Data System (ADS)

    Soubiran, C.; Blanco-Cuaresma, S.; Heiter, U.

    2014-12-01

    Open clusters are key objects to study the chemical evolution of the Galactic disk, but metallicities and detailed abundances are available for only a small fraction of them. We review here the current status of metallicity determinations. Open clusters are also perfect objects to test the chemical tagging method which intends to identify stars formed from the same molecular cloud. First results about this technique are presented, based on homogeneously derived chemical abundances for a large sample of stars in open clusters.

  1. Chemical Mahjong

    ERIC Educational Resources Information Center

    Cossairt, Travis J.; Grubbs, W. Tandy

    2011-01-01

    An open-access, Web-based mnemonic game is described whereby introductory chemistry knowledge is tested using mahjong solitaire game play. Several tile sets and board layouts are included that are themed upon different chemical topics. Introductory tile sets can be selected that prompt the player to match element names to symbols and metric…

  2. Chemical Change

    NSDL National Science Digital Library

    2012-06-26

    In this chemistry activity, learners explore the amount of copper in a new penny. Learners use toilet bowl cleaner to hollow out the interior of a penny with zinc inside. This experiment will demonstrate how chemical changes can separate matter. Learners can also discuss how zinc is cheaper than copper, in a lesson about economics.

  3. Chemical Ionization

    Microsoft Academic Search

    Jürgen H. Gross; Mass Spectrometry

    \\u000a Mass spectrometrists have ever been searching for ionization methods softer than EI, because molecular weight determination\\u000a is key for structure elucidation. Chemical ionization (CI) is the first of the so-called soft ionization methods we are going to discuss (cf. Fig. 1.2).

  4. Chemical Indicators.

    ERIC Educational Resources Information Center

    Prombain, Dorothy R.; And Others

    This science sourcebook was written for intermediate grade teachers to provide guidance in teaching a specially developed unit on chemical indicators. Directions and suggestions for guiding student science activities are given. Some of the activities concern soil testing, crystals, and household powders such as sugar and salt. A list of necessary…

  5. Derivation of Characteristic Formulae

    Microsoft Academic Search

    Markus Müller-Olm

    1998-01-01

    This paper shows how modal mu-calculus formulae characterizing finite-state processes up to strong or weak bisimulation can be derived directly from the well-known greatest fixpoint characterizations of the bisimulation relations. Our derivation simplifies earlier proofs for the strong bisimulation case and, by virtue of derivation, immediately generalizes to various other bisimulation-like relations, in particular weak bisimulation.

  6. Gaia Stellar Chemical Abundances and Galactic Archaeology

    NASA Astrophysics Data System (ADS)

    Recio-Blanco, A.; Thévenin, F.

    2005-01-01

    The chemical information derived from the Gaia data will be crucial for tagging stars in the Galaxy and thus for disentangling the Galactic history. The derivation of detailed chemical abundances using the Gaia tools (RVS, Astrometry, MBP) is examined exploring its impact on Galactic evolutionary models. We look into the difficulties for obtaining an accurate diagnostic of the Galactic chemical history, like NLTE effects, chromospheric activity and the consequences of the element diffusion in stellar interiors. Finally, we point out some open questions on the Galactic evolution that Gaia abundances can precisely help to answer.

  7. Chemical Reactions

    NSDL National Science Digital Library

    Mrs. Hicken

    2009-05-04

    We are going go over a general view of reactions to prepare us for our unit on Chemical Reactions! Have fun learning! WARNING: If you are caught looking at ANY other site, without permission, you will be sent to the ALC, and you will not participate in any other computer activities for the rest of the year. Get your worksheet and begin! Overview Take this quiz and have me come over and sign off on your worksheet when you have completed the quiz! Overview Quiz Next let's take a look at what effect the rate of a chemical reaction. Rates of Reactions Another quiz, another check off by me! Rates of Reactions Quiz Now how do we measure how fast a ...

  8. Chemical warfare

    PubMed Central

    Samuels, Richard Ian; Mattoso, Thalles Cardoso; Moreira, Denise D.O.

    2013-01-01

    Leaf-cutting ants are well known for their highly complex social organization, which provides them with a strong defense against parasites invading their colonies. Besides this attribute, these insects have morphological, physiological and structural characteristics further reinforcing the defense of their colonies. With the discovery of symbiotic bacteria present on the integument of leaf-cutting ants, a new line of defense was proposed and considered to be specific for the control of a specialized fungal parasite of the ants’ fungus gardens (Escovopsis). However, recent studies have questioned the specificity of the integumental bacteria, as they were also found to inhibit a range of fungi, including entomopathogens. The microbiota associated with the leaf-cutting ant gardens has also been proposed as another level of chemical defense, protecting the garden from parasite invasion. Here we review the chemical defense weaponry deployed by leaf-cutting ants against parasites of their fungus gardens and of the ants themselves. PMID:23795235

  9. Microbial chemical factories: recent advances in pathway engineering for synthesis of value added chemicals

    E-print Network

    Dhamankar, Himanshu Hemant

    The dwindling nature of petroleum and other fossil reserves has provided impetus towards microbial synthesis of fuels and value added chemicals from biomass-derived sugars as a renewable resource. Microbes have naturally ...

  10. Chemical Evolution of Galaxies

    NASA Astrophysics Data System (ADS)

    Matteucci, Francesca

    Models of galactic chemical evolution study how the chemical elements have formed and dispersed in the Universe. During the Big Bang, only light elements, such as hydrogen (H), deuterium (D), helium (He), and a very tiny fraction of lithium (7Li) were formed, while all the other elements from carbon to uranium and beyond were formed inside the stars. The chemical elements and their isotopes are characterized by their mass number (A), namely, the sum of the protons and neutrons composing their nuclei. So, when we write 7Li, it means that A= 7 for Li. Elements with A = 5 and A = 8 do not exist because they would not be stable, elements with A = 9, 10, 11 are the isotopes of berillium (Be) and boron (B), which are formed, together with 6Li and some 7Li during spallation processes, which derive from the interaction between cosmic rays and interstellar atoms of carbon (C), nitrogen (N), and oxygen (O). All the elements with A ? 12 starting from 12C have been synthesized inside the stars and the sum of all of them in Astronomy is called metallicity and indicated with capital Z.

  11. 21 CFR 189.120 - Cobaltous salts and its derivatives.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...2010-04-01 2009-04-01 true Cobaltous salts and its derivatives. 189.120 Section...Use as Human Food § 189.120 Cobaltous salts and its derivatives. (a) Cobaltous salts are the chemicals, CoC4 H6 O4 ,...

  12. 21 CFR 189.120 - Cobaltous salts and its derivatives.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...2011-04-01 2011-04-01 false Cobaltous salts and its derivatives. 189.120 Section...Use as Human Food § 189.120 Cobaltous salts and its derivatives. (a) Cobaltous salts are the chemicals, CoC4 H6 O4 ,...

  13. 21 CFR 189.120 - Cobaltous salts and its derivatives.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...2013-04-01 2013-04-01 false Cobaltous salts and its derivatives. 189.120 Section...Use as Human Food § 189.120 Cobaltous salts and its derivatives. (a) Cobaltous salts are the chemicals, CoC4 H6 O4 ,...

  14. 21 CFR 189.120 - Cobaltous salts and its derivatives.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...2014-04-01 2014-04-01 false Cobaltous salts and its derivatives. 189.120 Section...Use as Human Food § 189.120 Cobaltous salts and its derivatives. (a) Cobaltous salts are the chemicals, CoC4 H6 O4 ,...

  15. 21 CFR 189.120 - Cobaltous salts and its derivatives.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...2012-04-01 2012-04-01 false Cobaltous salts and its derivatives. 189.120 Section...Use as Human Food § 189.120 Cobaltous salts and its derivatives. (a) Cobaltous salts are the chemicals, CoC4 H6 O4 ,...

  16. Experimental and quantum-chemical studies of 1H, 13C and 15N NMR coordination shifts in Pd(II) and Pt(II) chloride complexes with methyl and phenyl derivatives of 2,2'-bipyridine and 1,10-phenanthroline.

    PubMed

    Pazderski, Leszek; Tousek, Jaromír; Sitkowski, Jerzy; Kozerski, Lech; Sz?yk, Edward

    2007-12-01

    1H, 13C and 15N NMR studies of platinide(II) (M=Pd, Pt) chloride complexes with methyl and phenyl derivatives of 2,2'-bipyridine and 1,10-phenanthroline [LL=4,4'-dimethyl-2,2'-bipyridine (dmbpy); 4,4'-diphenyl-2,2'-bipyridine (dpbpy); 4,7-dimethyl-1,10-phenanthroline (dmphen); 4,7-diphenyl-1,10-phenanthroline (dpphen)] having a general [M(LL)Cl2] formula were performed and the respective chemical shifts (delta1H, delta13C, delta15N) reported. 1H high-frequency coordination shifts (Delta1Hcoord=delta1Hcomplex-delta1Hligand) were discussed in relation to the changes of diamagnetic contribution in the relevant 1H shielding constants. The comparison to literature data for similar [M(LL)(XX)], [M(LL)X2] and [M(LL)XY] coordination or organometallic compounds containing various auxiliary ligands revealed a large dependence of delta1H parameters on inductive and anisotropic effects. 15N low-frequency coordination shifts (Delta15Ncoord=delta 15Ncomplex-delta15Nligand) of ca 88-96 ppm for M=Pd and ca 103-111 ppm for M=Pt were attributed to both the decrease of the absolute value of paramagnetic contribution and the increase of the diamagnetic term in the expression for 15N shielding constants. The absolute magnitude of Delta15Ncoord parameter increased by ca 15 ppm upon Pd(II)-->Pt(II) transition and by ca 6-7 ppm following dmbpy-->dmphen or dpbpy-->dpphen ligand replacement; variations between analogous complexes containing methyl and phenyl ligands (dmbpy vs dpbpy; dmphen vs dpphen) did not exceed+/-1.5 ppm. Experimental 1H, 13C, 15N NMR chemical shifts were compared to those quantum-chemically calculated by B3LYP/LanL2DZ+6-31G**//B3LYP/LanL2DZ+6-31G*, both in vacuo and in DMSO or DMF solution. PMID:18044804

  17. Endohedral Metallofullerene Derivatives

    NASA Technical Reports Server (NTRS)

    Dorn, Harry C. (Inventor); Iezzi, Erick B. (Inventor); Duchamp, James (Inventor)

    2008-01-01

    Trimetallic nitride endohedral metallofullerene derivatives and their preparation are described. The trimetallic nitride endohedral metallofullerene derivatives have the general formula A(sub 3-n)X(sub n)@C(sub m)(R) where n ranges from 0 to 3, A and X may be trivalent metals and may be either rare earth metal or group IIIB metals, m is between about 60 and about 200, and R is preferably an organic group. Derivatives where the R group forms cyclized derivatives with the fullerene cage are also described.

  18. Photosynthetic approaches to chemical biotechnology.

    PubMed

    Desai, Shuchi H; Atsumi, Shota

    2013-12-01

    National interest and environmental advocates encourage alternatives to petroleum-based products. Besides biofuels, many other valuable chemicals used in every-day life are petroleum derivatives or require petroleum for their production. A plausible alternative to production using petroleum for chemical production is to harvest the abundant carbon dioxide resources in the environment to produce valuable hydrocarbons. Currently, efforts are being made to utilize a natural biological system, photosynthetic microorganisms, to perform this task. Photosynthetic microorganisms are attractive to use for biochemical production because they utilize economical resources for survival: sunlight and carbon dioxide. This review examines the various compounds produced by photosynthetic microorganisms. PMID:23578466

  19. P MATRIX PROPERTIES, INJECTIVITY AND STABILITY IN CHEMICAL REACTION SYSTEMS

    E-print Network

    Banaji,. Murad

    P MATRIX PROPERTIES, INJECTIVITY AND STABILITY IN CHEMICAL REACTION SYSTEMS MURAD BANAJI§, PETE. Chemical reactions; P matrices; Injectivity; Stability; Mass action AMS subject classifications. 80A30; 15A48; 34D30 1. Introduction. In this paper we will study chemical reaction systems, and systems derived

  20. Carbon Nano Tube Composites with Chemically Functionalized Plant Oils

    Microsoft Academic Search

    Wim Thielemans; Richard P. Wool; Werner Blau; Valerie Barron

    2003-01-01

    Carbon Nano Tube Composites with Chemically Functionalized Plant Oil Wim Thielemans, R., P. Wool, V. Barron and W. Blau Multi-Wall Carbon Nano Tubes (MWCNT) made by the Kratchmer-Huffman CCVD process were found to interact and solubilize by slow mechanical stirring, with chemically functionalized plant oils, such as acrylated, epoxidized and maleinated triglycerides (TG) derived from plant oils. The chemical functionality

  1. Antitumour Polysaccharide derived Chemically from Natural Glucan (Pachyman)

    Microsoft Academic Search

    Goro Chihara; Junji Hamuro; Yukiko Maeda; Yoshiko Arai; Fumiko Fukuoka

    1970-01-01

    WE have reported1 that the polysaccharide lentinan obtained from Lentinus edodes (Berk.) Sing. (a popular edible mushroom in Japan) had a strong antitumour activity against sarcoma 180 implanted subcutaneously in mice, and that almost complete regression of the tumours had been observed after ten doses of 1 mg\\/kg. Lentinan is a beta-(1-->3)-linked linear glucan having a molecular weight of 950,000-1,050,000

  2. Physical and chemical characterization of waste wood derived biochars

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Biochar, a solid byproduct generated during waste biomass pyrolysis or gasification in the absence (or near-absence) of oxygen, has recently garnered interest for both agricultural and environmental management purposes owing to its unique physicochemical properties, such as its high surface area and...

  3. Quantum chemical assessment of benzimidazole derivatives as corrosion inhibitors

    PubMed Central

    2014-01-01

    Background The majority of well-known inhibitors are organic compounds containing multiple bonds and heteroatoms, such as O, N or S, which allow adsorption onto the metal surface. These compounds can adsorb onto the metal surface and block active surface sites, reducing the rate of corrosion. Results A comparative theoretical study of three benzimidazole isomers, benzimidazole (BI), 2-methylbenzimidazole (2-CH3-BI), and 2-mercaptobenzimidazole (2-SH-BI), as corrosion inhibitors was performed using density functional theory (DFT) with the B3LYP functional basis set. Conclusions Nitro and amino groups were selected for investigation as substituents of the three corrosion inhibitors. Nitration of the corrosion inhibitor molecules led to a decrease in inhibition efficiency, while reduction of the nitro group led to an increase in inhibition efficiency. These aminobenzimidazole isomers represent a significant improvement in the inhibition efficiency of corrosion inhibitor molecules. PMID:24674343

  4. Quantum-chemical evaluation of basicity of acridine derivatives

    SciTech Connect

    Pedash, V.F.; Gaidukevich, A.N.

    1986-08-01

    It has been found that the antibacterial effect of aminoacridines increases with the increase of the degree of their cationic ionization, while changes in the structure are relatively minor as concern the activity. The authors study the possible determination of a dependence between the pK of monosubstituted acridines on the position of substituent in their molecules. The theory of perturbations of molecular orbitals in its simplest variation was used. A comparison is shown of theoretical and experimental data on pK of monoaminoacridines.

  5. Nonlinear response theory in chemical kinetics

    PubMed Central

    Kryvohuz, Maksym; Mukamel, Shaul

    2014-01-01

    A theory of nonlinear response of chemical kinetics, in which multiple perturbations are used to probe the time evolution of nonlinear chemical systems, is developed. Expressions for nonlinear chemical response functions and susceptibilities, which can serve as multidimensional measures of the kinetic pathways and rates, are derived. A new class of multidimensional measures that combine multiple perturbations and measurements is also introduced. Nonlinear fluctuation-dissipation relations for steady-state chemical systems, which replace operations of concentration measurement and perturbations, are proposed. Several applications to the analysis of complex reaction mechanisms are provided. PMID:25669367

  6. Partial Derivative Visualization Gallery

    NSDL National Science Digital Library

    Roberts, Lila F.

    2004-11-11

    This resource is a small gallery of demos for illustrating partial derivatives geometrically. These animations can be used by instructors in a classroom setting or by students to aid in acquiring a visualization background for partial derivatives. Two file formats, gif and QuickTime files are used for the animations which can be downloaded.

  7. Chemical Analyses

    NASA Technical Reports Server (NTRS)

    Bulluck, J. W.; Rushing, R. A.

    1994-01-01

    As a preliminary study on the effects of chemical aging of polymer materials MERL and TRI have examined two polymeric materials that are typically used for offshore umbilical applications. These two materials were Tefzel, a copolymer of ethylene and tetrafluoroethylene, and Coflon, polyvinylidene fluoride. The Coflon specimens were cut from pipe sections and exposed to H2S at various temperatures and pressures. One of these specimens was tested for methane permeation, and another for H2S permeation. The Tefzel specimens were cut from .05 mm sheet stock material and were exposed to methanol at elevated temperature and pressure. One of these specimens was exposed to methanol permeation for 2 days at 100 C and 2500 psi. An additional specimen was exposed to liquid methanol for 3 days at 150 C and 15 Bar. Virgin specimens of each material were similarly prepared and tested.

  8. CHEMICAL REACTIONS AS -LIMIT OF DIFFUSION MARK A. PELETIER, GIUSEPPE SAVARE, AND MARCO VENERONI

    E-print Network

    Veneroni, Marco

    CHEMICAL REACTIONS AS -LIMIT OF DIFFUSION MARK A. PELETIER, GIUSEPPE SAVAR´E, AND MARCO VENERONI a rigorous proof of Kramers's formal derivation, and we show how chemical reactions and diffusion processes can be embedded in a common framework. This allows one to derive a chemical reaction as a singular

  9. Chemical information science coverage in Chemical Abstracts.

    PubMed

    Wiggins, G

    1987-02-01

    For many years Chemical Abstracts has included in its coverage publications on chemical documentation or chemical information science. Although the bulk of those publications can be found in section 20 of Chemical Abstracts, many relevant articles were found scattered among 39 other sections of CA in 1984-1985. In addition to the scattering of references in CA, the comprehensiveness of Chemical Abstracts as a secondary source for chemical information science is called into question. Data are provided on the journals that contributed the most references on chemical information science and on the languages of publication of relevant articles. PMID:3558505

  10. Renewable Chemicals: Dehydroxylation of Glycerol and Polyols

    PubMed Central

    ten Dam, Jeroen; Hanefeld, Ulf

    2011-01-01

    The production of renewable chemicals is gaining attention over the past few years. The natural resources from which they can be derived in a sustainable way are most abundant in sugars, cellulose and hemicellulose. These highly functionalized molecules need to be de-functionalized in order to be feedstocks for the chemical industry. A fundamentally different approach to chemistry thus becomes necessary, since the traditionally employed oil-based chemicals normally lack functionality. This new chemical toolbox needs to be designed to guarantee the demands of future generations at a reasonable price. The surplus of functionality in sugars and glycerol consists of alcohol groups. To yield suitable renewable chemicals these natural products need to be defunctionalized by means of dehydroxylation. Here we review the possible approaches and evaluate them from a fundamental chemical aspect. PMID:21887771

  11. 40 CFR 721.5358 - 2-propanol, 1,1?,1?-nitrilotris-, compds. with ethanol 2-[2-(C12-14- alkyloxy) ethoxy] derivs...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...C12-14- alkyloxy) ethoxy] derivs. hydrogen sulfates. 721.5358 Section 721... 14- alkyloxy) ethoxy] derivs. hydrogen sulfates. (a) Chemical substance...C12-14 - alkyloxy) ethoxy] derivs. hydrogen sulfates (PMN P-99-928;...

  12. Derivative Matching Game

    NSDL National Science Digital Library

    Once again, the Mathematical Association of America has struck instructional gold with this latest gem from their online collection of resources for mathematics educators. Created by Barbara Margolius, this derivative matching game presents users with a game board showing graphs of functions on cards. Essentially, the goal of the game is to match the functions with their derivatives. Visitors can begin by reading an overview of the game, along with some brief instructions, and then they should dive right in. The game can also be customized to match functions with just first derivatives or both first and second derivatives. Mathematics educators will have a lot of fun with this one, and even the mathematically uncertain can be drawn into the fold with this easy to use resource.

  13. Derivative actions in China 

    E-print Network

    Lin, Shaowei

    2014-07-02

    The enactment of derivative action was expected to be actively used by shareholders to protect their interests. In fact, it turned out that this reform effort seemed futile as the right to engage in such actions was ...

  14. Definitions Derived from Neutrosophics

    E-print Network

    Florentin Smarandache

    2003-01-28

    Thirty-three new definitions are presented, derived from neutrosophic set, neutrosophic probability, neutrosophic statistics, and neutrosophic logic. Each one is independent, short, with references and cross references like in a dictionary style.

  15. Definitions Derived from Neutrosophics

    Microsoft Academic Search

    Florentin Smarandache

    2003-01-01

    Thirty-three new definitions are presented, derived from neutrosophic set, neutrosophic probability, neutrosophic statistics, and neutrosophic logic. Each one is independent, short, with references and cross references like in a dictionary style.

  16. Synthesis of phenoxatellurine derivatives

    SciTech Connect

    Maksimenko, A.A.; Rivkin, B.B.; Sadekov, I.D.; Minkin, V.I.

    1985-12-01

    The reaction of dimedon enol acetate with tellurium tetrachloride gives derivatives of octahydrophenoxatellurine. The reaction of cyclohexanone enol acetate and methyl ethyl ketone with tellurium tetrachloride or aryltellurium trichloride gives the respective organotellurium trichloride and diorganotellurium dichloride.

  17. Effects of metformin, buformin, and phenformin on the post-initiation stage of chemically induced mammary carcinogenesis in the rat.

    PubMed

    Zhu, Zongjian; Jiang, Weiqin; Thompson, Matthew D; Echeverria, Dimas; McGinley, John N; Thompson, Henry J

    2015-06-01

    Metformin is a widely prescribed drug for the treatment of type II diabetes. Although epidemiologic data have provided a strong rationale for investigating the potential of this biguanide for use in cancer prevention and control, uncertainty exists whether metformin should be expected to have an impact in nondiabetic patients. Furthermore, little attention has been given to the possibility that other biguanides may have anticancer activity. In this study, the effects of clinically relevant doses of metformin (9.3 mmol/kg diet), buformin (7.6 mmol/kg diet), and phenformin (5.0 mmol/kg diet) were compared with rats fed control diet (AIN93-G) during the post-initiation stage of 1-methyl-1-nitrosourea-induced (50 mg/kg body weight) mammary carcinogenesis (n = 30/group). Plasma, liver, skeletal muscle, visceral fat, mammary gland, and mammary carcinoma concentrations of the biguanides were determined. In comparison with the control group, buformin decreased cancer incidence, multiplicity, and burden, whereas metformin and phenformin had no statistically significant effect on the carcinogenic process relative to the control group. Buformin did not alter fasting plasma glucose or insulin. Within mammary carcinomas, evidence was obtained that buformin treatment perturbed signaling pathways related to energy sensing. However, further investigation is needed to determine the relative contributions of host systemic and cell autonomous mechanisms to the anticancer activity of biguanides such as buformin. Cancer Prev Res; 8(6); 518-27. ©2015 AACR. PMID:25804611

  18. Derived Hall Algebras

    Microsoft Academic Search

    Bertrand Toen

    2005-01-01

    The purpose of this work is to define a derived Hall algebra $\\\\mathcal{DH}(T)$, associated to any dg-category $T$ (under some finiteness conditions). Our main theorem states that $\\\\mathcal{DH}(T)$ is associative and unital. It is shown that $\\\\mathcal{DH}(T)$ contains the usual Hall algebra $\\\\mathcal{H}(T)$ when $T$ is an abelian category. We will also prove an explicit formula for the derived Hall

  19. CHEMICAL PACEMAKERS

    PubMed Central

    Hadidian, Zareh; Hoagland, Hudson

    1939-01-01

    1. Iron spicules found in the brains of general paretic patients are formed from endogenous brain iron normally present in another form. This supports our earlier view that the µ value of 16,000 obtained in advanced paretics for alpha brain wave frequencies as a measure of cortical respiration comes about from the slowing of an iron catalyzed link in cortical respiration such as would result from the reduction of available cytochrome and its oxidase, thus making this step a chemical pacemaker. 2. To test the basic theory of chemical pacemakers, a study was made of the succinate-fumarate enzyme system containing succino-dehydrogenase and cytochrome-cytochrome oxidase acting sequentially. 3. The µ value for the unpoisoned system is 11,200 ± 200 calories. 4. According to theory, the addition of a critical amount of cyanide known to be a specific poison of the cytochrome-cytochrome oxidase system (and not of the dehydrogenase) should shift the µ cleanly to 16,000 calories, and it does. 5. According to theory, selenite, a specific poison for the dehydrogenase, should stop all respiration without shifting the µ. This also is found to be the case. 6. The theory also predicts that if the µ is shifted from 11,000 ± to 16,000 ± by cyanide, the subsequent addition of a critical amount of selenite should shift the µ back again to 11,000 ± calories, and this is found to occur. 7. It is concluded that approximately 11,000 calories is the energy of activation of the succino-dehydrogenase-catalyzed step and 16,000 calories is that for the cytochrome-cytochrome oxidase-catalyzed step. These two values are encountered more frequently than any others in physiological systems. It is to be recalled that a shift of µ for alpha brain wave frequencies from 11,000 to 16,000 calories occurs in the course of advancing syphilitic brain infection and is accompanied by a change in form of brain iron. PMID:19873142

  20. Exposure Levels for Chemical Threat Compounds; Information to Facilitate Chemical Incident Response

    SciTech Connect

    Hauschild, Veronique [U.S. Army Public Health Command] [U.S. Army Public Health Command; Watson, Annetta Paule [ORNL] [ORNL

    2013-01-01

    Exposure Standards, Limits and Guidelines for Chemical Threat Compunds ABSTRACT Exposure criteria for chemical warfare (CW) agents and certain toxic industrial chemicals (TICs) used as CW agents (such as chlorine fill in an improvised explosive device) have been developed for protection of the civilian general public, civilian employees in chemical agent processing facilities and deployed military populations. In addition, compound-specific concentrations have been developed to serve as how clean is clean enough clearance criteria guiding facility recovery following chemical terrorist or other hazardous release events. Such criteria are also useful to verify compound absence, identify containment boundaries and expedite facility recovery following chemical threat release. There is no single right value or concentration appropriate for all chemical hazard control applications. It is acknowledged that locating and comparing the many sources of CW agent and TIC exposure criteria has not been previously well-defined. This paper summarizes many of these estimates and assembles critical documentation regarding their derivation and use.

  1. [Chemical food contaminants].

    PubMed

    Schrenk, D

    2004-09-01

    Chemical food contaminants are substances which are neither present naturally in the usual raw material used for food production nor are added during the regular production process. Examples are environmental pollutants or contaminants derived from agricultural production of crops or livestock or from inadequate manufacturing of the food product itself. More difficult is the classification of those compounds formed during regular manufacturing such as products of thermal processes including flavoring substances. In these cases, it is common practice to call those compounds contaminants which are known for their adverse effects such as acrylamide, whereas constituents which add to the food-specific flavor such as Maillard products formed during roasting, baking etc. are not termed contaminants. From a toxicological viewpoint this distinction is not always clear-cut. Important groups of chemical contaminants are metals such as mercury or lead, persistent organic pollutants such as polychlorinated biphenyls and related pollutants, which are regularly found in certain types of food originating from background levels of these compounds in our environment. Furthermore, natural toxins form microorganisms or plants, and compounds formed during thermal treatment of food are of major interest. In general, a scientific risk assessment has to be carried out for any known contaminant. This comprises an exposure analysis and a toxicological and epidemiological assessment. On these grounds, regulatory and/or technological measures can often improve the situation. Major conditions for a scientific risk assessment and a successful implementation of regulations are highly developed food quality control, food toxicology and nutritional epidemiology. PMID:15378171

  2. Chemical Homogeneity in Collinder 261 and Implications for Chemical Tagging

    E-print Network

    G. M. De Silva; K. C. Freeman; M. Asplund; J. Bland-Hawthorn; M. S. Bessell; R. Collet

    2006-11-28

    This paper presents abundances for 12 red giants of the old open cluster Collinder 261 based on spectra from VLT/UVES. Abundances were derived for Na, Mg, Si, Ca, Mn, Fe, Ni, Zr and Ba. We find the cluster has a solar-level metallicity of [Fe/H] = -0.03 dex. However some alpha elements were found to be enhanced. The star-to-star scatter was consistent with the expected measurement uncertainty for all elements. The observed rms scatter is as follows: Na = 0.07, Mg = 0.05, Si = 0.06, Ca = 0.05, Mn = 0.03, Fe = 0.02, Ni = 0.04, Zr = 0.12, and Ba = 0.03 dex. The intrinsic scatter was estimated to be less than 0.05 dex. Such high levels of homogeneity indicate that chemical information remains preserved in this old open cluster. We use the chemical homogeneity we have now established in Cr 261, Hyades and the HR1614 moving group to examine the uniqueness of the individual cluster abundance patterns, ie. chemical signatures. We demonstrate that the three studied clusters have unique chemical signatures, and discuss how other such signatures may be searched for in the future. Our findings support the prospect of chemically tagging disk stars to common formation sites in order to unravel the dissipative history of the Galactic disk.

  3. Optimization of Source Identification Algorithm Derived from Moth-Inspired Plume Tracing Strategies

    Microsoft Academic Search

    Wei Li; Joseph E. Sutton

    2007-01-01

    This paper presents a method of designing and optimizing a single chemical sensor-based source identification algorithm, derived from moth-inspired chemical plume tracing (CPT) strategies. In doing it, we define a source identification zone (SIZ) using last chemical detection points (LCDPs). Then, we optimize the proposed algorithm using a simulated plume with significant meander and filament intermittency by considering dynamics of

  4. PREDICTION OF OCTANOL/WATER PARTITION COEFFICIENT (KOW) WITH ALGORITHMICALLY DERIVED VARIABLES

    EPA Science Inventory

    A statistical model was developed with algorithmically derived independent variables based on chemical structure for prediction of octanol/water partition coefficients (Kow) measured for more than 4,000 chemicals. he procedure first classified the chemicals into 14 groups based o...

  5. Protective Effects of Synthetic Hydroxytyrosol Acetyl Derivatives against Oxidative Stress in Human Cells

    Microsoft Academic Search

    Caterina Manna; Valentina Migliardi; Filomena Sannino; Antonio De Martino; Renato Capasso

    2005-01-01

    Chemically stable di- and triacetyl derivatives of the natural o-diphenol antioxidant hydroxytyrosol were synthesized, and their chemical and biological antioxidant activities were assessed in comparison with that of the native synthetic compound. The chemical antioxidant activity of the selected compounds was evaluated by measuring the ferric reducing antioxidant power (FRAP). The data clearly indicate that, as expected, the hydroxytyrosol analogues,

  6. Chalcone and dihydrochalcone derivatives from the orchid Lusia volucris

    Microsoft Academic Search

    P. L. Majumder; S. Lahiri; N. Mukhoti

    1995-01-01

    A new dihydrochalcone derivative, lusianin, two other known chalcones and a phenanthrene derivative were isolated from the orchid Lusia volucris. The two chalcones and the phenanthrene derivative were characterized as 2-propene-1-one-1-(2?,4?-dihydroxy-3?-methoxyphenyl)-3-(4?-methoxyphenyl) and 2-propene-1-one-1-(2?-hydroxy-4?-methoxyphenyl)-3-(4?-methoxyphenyl) and 6-hydroxy-2,4,7-trimethoxyphenanthrene(batatasin-I), respectively, by independent spectral analysis of the compounds and their acetyl derivatives. The structure of lusianin was established as 1-propanone-1-(2?,4?-dihydroxy-3?-methoxyphenyl)-3-(4?-methoxyphenyl) from spectral and chemical evidence.

  7. Chemical oscillator as a generalized Rayleigh oscillator

    NASA Astrophysics Data System (ADS)

    Ghosh, Shyamolina; Ray, Deb Shankar

    2013-10-01

    We derive the conditions under which a set of arbitrary two dimensional autonomous kinetic equations can be reduced to the form of a generalized Rayleigh oscillator which admits of limit cycle solution. This is based on a linear transformation of field variables which can be found by inspection of the kinetic equations. We illustrate the scheme with the help of several chemical and bio-chemical oscillator models to show how they can be cast as a generalized Rayleigh oscillator.

  8. TECHNICAL BASIS FOR NARCOTIC CHEMICALS AND POLYCYCLIC AROMATIC HYDROCARBON CRITERIA. I. WATER AND TISSUE

    Microsoft Academic Search

    Dominic M. Di Toro; Joy A. McGrath; David J. Hansen

    2000-01-01

    A method is presented for developing water quality criteria (WQC) for type I narcotic chemicals in general and PAHs in particular. The criteria can be applied to any individual or mixture of narcotic chemicals using only the chemical's octanol-water partition coefficient KOW. It is derived from a database of LC50s comprising 156 chemicals and 33 species, including fish, amphibians, arthropods,

  9. The impact of chemical evolution on the observable properties of stellar populations

    E-print Network

    M. Tosi

    2000-08-22

    The major effects of the chemical evolution of galaxies on the characteristics of their stellar populations are reviewed. A few examples of how the observed stellar properties derived from colour--magnitude diagrams can constrain chemical evolution models are given.

  10. Chemical Growth Regulators for Guayule Plants

    NASA Technical Reports Server (NTRS)

    Dastoor, M. N.; Schubert, W. W.; Petersen, G. R.

    1982-01-01

    Test Tubes containing Guayule - tissue cultures were used in experiments to test effects of chemical-growth regulators. The shoots grew in response to addition of 2-(3,4-dichlorophenoxy)-triethylamine (triethylamine (TEA) derivative) to agar medium. Preliminary results indicate that a class of compounds that promotes growth in soil may also promote growth in a culture medium. Further experiments are needed to define the effect of the TEA derivative.

  11. Tunable Raman spectroscopy study of CVD and peapod-derived bundled and individual double-wall carbon nanotubes

    E-print Network

    Dresselhaus, Mildred

    We use 40 laser excitation energies to analyze the differences in the Raman spectra from chemical vapor deposition-derived double-wall carbon nanotube (CVD-DWNT) bundles, fullerene-derived DWNT bundles (C[subscript 60]-DWNTs), ...

  12. Derivative-Free Optimization

    Microsoft Academic Search

    Oliver Kramer; David Ciaurri; Slawomir Koziel

    \\u000a In many engineering applications it is common to find optimization problems where the cost function and\\/or constraints require\\u000a complex simulations. Though it is often, but not always, theoretically possible in these cases to extract derivative information\\u000a efficiently, the associated implementation procedures are typically non-trivial and time-consuming (e.g., adjoint-based methodologies).\\u000a Derivative-free (non-invasive, black-box) optimization has lately received considerable attention within the

  13. Modern Chemical Technology, Guidebook for Chemical Technicians.

    ERIC Educational Resources Information Center

    Pecsok, Robert L.; Chapman, Kenneth

    This volume is a part of the ACS "Modern Chemical Technology" (ChemTeC) curriculum that is developed for chemical technicians. It is intended as a handbook that will be used throughout the instruction. Safety is stressed in eight of the ten chapters under the headings: safety in the chemical laboratory, personal protective equipment, fire safety…

  14. The Chemical Engineer in the Chemical Industry.

    ERIC Educational Resources Information Center

    Zabicky, Jacob

    1986-01-01

    Describes a course for third- or fourth-year chemical engineering students designed to acquaint them with the chemical industry. The course deals with productivity, characteristics of the chemical industry, sources of information, industrial intelligence, research and development, patent law, technology transfer, and quality control. (TW)

  15. CHEMICAL SAFETY ALERTS-

    EPA Science Inventory

    Chemical Safety Alerts are short publications which explain specific hazards that have become evident through chemical accident investigation efforts. EPA has produced over a dozen Alerts to date. This year's Alert: Managing Chemical Reactivity Hazards...

  16. CHEMICALS IN PROGRESS BULLETIN

    EPA Science Inventory

    Chemicals in Progress Bulletin is a quarterly newsletter which highlights regulatory and program activities of the Office of Pollution Prevention and Toxics. Regular features and news items include the existing chemicals program, new chemicals program, pollution prevention activi...

  17. Chemical methods for the production of graphenes.

    PubMed

    Park, Sungjin; Ruoff, Rodney S

    2009-04-01

    Interest in graphene centres on its excellent mechanical, electrical, thermal and optical properties, its very high specific surface area, and our ability to influence these properties through chemical functionalization. There are a number of methods for generating graphene and chemically modified graphene from graphite and derivatives of graphite, each with different advantages and disadvantages. Here we review the use of colloidal suspensions to produce new materials composed of graphene and chemically modified graphene. This approach is both versatile and scalable, and is adaptable to a wide variety of applications. PMID:19350030

  18. 40 CFR 721.6110 - Alkyldi(alkyloxyhydroxypropyl) derivative, phosphoric acid esters, potassium salts.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...derivative, phosphoric acid esters, potassium salts. 721.6110 Section 721.6110 Protection...derivative, phosphoric acid esters, potassium salts. (a) Chemical substance and significant...derivative, phosphoric acid esters, potassium salts (PMN P-91-818) is subject to...

  19. 40 CFR 721.6110 - Alkyldi(alkyloxyhydroxypropyl) derivative, phosphoric acid esters, potassium salts.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...derivative, phosphoric acid esters, potassium salts. 721.6110 Section 721.6110 Protection...derivative, phosphoric acid esters, potassium salts. (a) Chemical substance and significant...derivative, phosphoric acid esters, potassium salts (PMN P-91-818) is subject to...

  20. 40 CFR 721.6110 - Alkyldi(alkyloxyhydroxypropyl) derivative, phosphoric acid esters, potassium salts.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...derivative, phosphoric acid esters, potassium salts. 721.6110 Section 721.6110 Protection...derivative, phosphoric acid esters, potassium salts. (a) Chemical substance and significant...derivative, phosphoric acid esters, potassium salts (PMN P-91-818) is subject to...

  1. Algal Sensory Chemical Ecology

    Microsoft Academic Search

    Charles D. Amsler

    Sensory chemical ecology is the branch of chemical ecology that focuses on chemical communications between organisms and chemical\\u000a sensing of the environment by organisms. Algae are well known to have numerous physiological responses to variations in their\\u000a chemical environment, particularly with respect to nutrients (Lobban and Harrison 1994). However, with respect to environmental\\u000a sensing it is typical for “chemical ecology”

  2. 15N NMR of 1,4-dihydropyridine derivatives.

    PubMed

    Goba, Inguna; Liepinsh, Edvards

    2013-07-01

    In this article, we describe the characteristic (15)N and (1)HN NMR chemical shifts and (1)J((15)N-(1)H) coupling constants of various symmetrically and unsymmetrically substituted 1,4-dihydropyridine derivatives. The NMR chemical shifts and coupling constants are discussed in terms of their relationship to structural features such as character and position of the substituent in heterocycle, N-alkyl substitution, nitrogen lone pair delocalization within the conjugated system, and steric effects. PMID:23696534

  3. Fractional Derivative Cosmology

    E-print Network

    Mark D. Roberts

    2009-09-07

    The degree by which a function can be differentiated need not be restricted to integer values. Usually most of the field equations of physics are taken to be second order, curiosity asks what happens if this is only approximately the case and the field equations are nearly second order. For Robertson-Walker cosmology there is a simple fractional modification of the Friedman and conservation equations. In general fractional gravitational equations similar to Einstein's are hard to define as this requires fractional derivative geometry. What fractional derivative geometry might entail is briefly looked at and it turns out that even asking very simple questions in two dimensions leads to ambiguous or intractable results. A two dimensional line element which depends on the Gamma-function is looked at.

  4. Derived Hall algebras

    Microsoft Academic Search

    Bertrand Toën

    2006-01-01

    The purpose of this work is to define a derived Hall algebra $\\\\mathcal{DH}(T)$ , associated to any differential graded (DG) category $T$ (under some finiteness conditions), generalizing the Hall algebra of an abelian category. Our main theorem states that $\\\\mathcal{DH}(T)$ is associative and unital. When the associated triangulated category $[T]$ is endowed with a t-structure with heart $\\\\mathcal{A}$ , it

  5. Derived Equivalences by Quantization

    Microsoft Academic Search

    Dmitry Kaledin

    2008-01-01

    We assume given a smooth symplectic (in the algebraic sense) resolution $X$\\u000aof an affine algebraic variety $Y$, and we prove that, possibly after replacing\\u000a$Y$ with an etale neighborhood of a point, the derived category of coherent\\u000asheaves on $X$ is equivalent to the dervied category of finitely generated left\\u000amodules over a non-commutative algebra $R$, a non-commutative resolution

  6. Chemistry and Chemical Engineering

    E-print Network

    Paxton, Anthony T.

    2011 SCHOOL OF Chemistry and Chemical Engineering Information for Candidates APPOINTMENT OF PROFESSOR OF CHEMICAL ENGINEERING #12;#12;SCHOOL OF Chemistry and Chemical Engineering 3 Thank you for your 6-7 School of Chemistry and Chemical Engineering 8-9 Staff Profiles 10-11 Queen's and Northern

  7. Chemical cloud tracking systems

    Microsoft Academic Search

    Larry B. Grim; Thomas C. Gruber; Martin Marshall; Brad Rowland

    2002-01-01

    This paper describes the Chemical Cloud Tracking System (CCTS) which has been installed at Dugway Proving Ground. The CCTS allows mapping of chemical clouds in real time from a safe standoff distance. The instruments used are passive standoff chemical agent detectors (FTIRs). Each instrument individually can only measure the total of all the chemical in its line-of-site; the distance to

  8. Chemical ecology of rotifers

    Microsoft Academic Search

    Terry W. Snell

    1998-01-01

    One of the primary channels of sensory input for zooplankton are chemical signals. Much zooplankton behavior is triggered by chemical stimuli, including feeding, predator defense, mating, and migration. Chemically regulated zooplankton behavior affects larger scale ecosystem processes like grazing, recruitment and secondary production. Knowledge of how chemicals transmit information about location, food quality, conspecifics, competitors, and predators is critical for

  9. Multimedia regulated chemicals

    SciTech Connect

    Lee, C.C.; Huffman, G.L. [Environmental Protection Agency, Cincinnati, OH (United States). National Risk Management Research Lab.; Mao, Y.L. [Soochow Univ., Taipei (Taiwan, Province of China). Dept. of Chemistry

    1999-10-01

    This article examines those chemicals that are listed in either environmental laws or regulations. Its objective is to help readers determine which laws regulate what types of chemicals and which types of chemicals are regulated by what laws. It is multimedia in scope, describing the various chemicals that are regulated in the different media (i.e., air, water, or land).

  10. PINS chemical identification software

    DOEpatents

    Caffrey, Augustine J.; Krebs, Kennth M.

    2004-09-14

    An apparatus and method for identifying a chemical compound. A neutron source delivers neutrons into the chemical compound. The nuclei of chemical elements constituting the chemical compound emit gamma rays upon interaction with the neutrons. The gamma rays are characteristic of the chemical elements constituting the chemical compound. A spectrum of the gamma rays is generated having a detection count and an energy scale. The energy scale is calibrated by comparing peaks in the spectrum to energies of pre-selected chemical elements in the spectrum. A least-squares fit completes the calibration. The chemical elements constituting the chemical compound can be readily determined, which then allows for identification of the chemical compound.

  11. Bacterial degradation of chlorophenols and their derivatives

    PubMed Central

    2014-01-01

    Chlorophenols (CPs) and their derivatives are persistent environmental pollutants which are used in the manufacture of dyes, drugs, pesticides and other industrial products. CPs, which include monochlorophenols, polychlorophenols, chloronitrophenols, chloroaminophenols and chloromethylphenols, are highly toxic to living beings due to their carcinogenic, mutagenic and cytotoxic properties. Several physico-chemical and biological methods have been used for removal of CPs from the environment. Bacterial degradation has been considered a cost-effective and eco-friendly method of removing CPs from the environment. Several bacteria that use CPs as their sole carbon and energy sources have been isolated and characterized. Additionally, the metabolic pathways for degradation of CPs have been studied in bacteria and the genes and enzymes involved in the degradation of various CPs have been identified and characterized. This review describes the biochemical and genetic basis of the degradation of CPs and their derivatives. PMID:24589366

  12. [The recent development of fiber-optic chemical sensor].

    PubMed

    Wang, Jian; Wei, Jian-ping; Yang, Bo; Gao, Zhi-yang; Zhang, Li-wei; Yang, Xue-feng

    2014-08-01

    The present article provides a brief review of recent research on fiber-optic chemical sensor technology and the future development trends. Especially, fiber-optic pH chemical sensor, fiber-optic ion chemicl sensor, and fiber-optic gas chemical sensor are introduced respectively. Sensing film preparation methods such as chemical bonding method and sol-gel method were briefly reviewed. The emergence of new type fiber-microstructured optical fiber opened up a new development direction for fiber-optic chemical sensor. Because of its large inner surface area, flexible design of structure, having internal sensing places in fibers, it has rapidly become an important development direction and research focus of the fiber-optic chemical sensors. The fiber-optic chemical sensor derived from microstructured optical fiber is also discussed in detail. Finally, we look to the future of the fiber-optic chemical sensor. PMID:25474930

  13. [The recent development of fiber-optic chemical sensor].

    PubMed

    Wang, Jian; Wei, Jian-ping; Yang, Bo; Gao, Zhi-yang; Zhang, Li-wei; Yang, Xue-feng

    2014-08-01

    The present article provides a brief review of recent research on fiber-optic chemical sensor technology and the future development trends. Especially, fiber-optic pH chemical sensor, fiber-optic ion chemicl sensor, and fiber-optic gas chemical sensor are introduced respectively. Sensing film preparation methods such as chemical bonding method and sol-gel method were briefly reviewed. The emergence of new type fiber-microstructured optical fiber opened up a new development direction for fiber-optic chemical sensor. Because of its large inner surface area, flexible design of structure, having internal sensing places in fibers, it has rapidly become an important development direction and research focus of the fiber-optic chemical sensors. The fiber-optic chemical sensor derived from microstructured optical fiber is also discussed in detail. Finally, we look to the future of the fiber-optic chemical sensor. PMID:25508709

  14. Chemical engineers design, control and optimize large-scale chemical,

    E-print Network

    Rohs, Remo

    38 Chemical engineers design, control and optimize large-scale chemical, physicochemical and electronics fields. Chemical Engineers are employed in areas as diverse as the chemical, pharmaceutical, petrochemical and environmental industries. Emerging fields in chemical engineering include biotechnology

  15. Platform Chemicals from an Oilseed Biorefinery

    SciTech Connect

    Tupy, Mike; Schrodi Yann

    2006-11-06

    The US chemical industry is $460 billion in size where a $150 billion segment of which is non-oxygenated chemicals that is sourced today via petroleum but is addressable by a renewable feedstock if one considers a more chemically reduced feedstock such as vegetable oils. Vegetable oil, due to its chemical functionality, provides a largely untapped opportunity as a renewable chemical source to replace petroleum-derived chemicals and produce platform chemicals unavailable today. This project examined the fertile intersection between the rich building blocks provided by vegetable oils and the enhanced chemical modification capability provided by metathesis chemistry. The technology advanced in this study is the process of ethylene cross-metathesis (referred to as ethenolysis) with vegetable oil and vegetable oil derivatives to manufacture the platform-chemical 9-decenoic acid (or 9DA) and olefin co-products. The project team meet its goals of demonstrating improved catalyst efficiencies of several multiples, deepening the mechanistic understanding of metathesis, synthesis and screening of dozens of new catalysts, designing and modeling commercial processes, and estimating production costs. One demonstrable result of the study was a step change improvement in catalyst turnover number in the ethenolysis of methyl oleate as reported here. We met our key measurable of producing 100 lbs of 9DA at the pilot-scale, which demonstrated ability to scale-up ethenolysis. DOE Project funding had significant positive impact on development of metathetically modified vegetable oils more broadly as the Cargill/Materia partnership, that was able to initiate primarily due to DOE funding, has succeeded in commercializing products, validating metathesis as a platform technology, and expanding a diverse products portfolio in high value and in large volume markets. Opportunities have expanded and business development has gained considerable momentum and enabled further expansion of the Materia/Cargill relationship. This project exceeded expectations and is having immediate impact on DOE success by replacing petroleum products with renewables in a large volume application today.

  16. Mathematical and numerical modeling for a bio-chemical aquarium

    E-print Network

    Fazio, Riccardo

    Mathematical and numerical modeling for a bio-chemical aquarium Riccardo Fazio *, Alessandra Based on bio-chemical ground we derive an aquarium mathematical model useful for predicting dangerous equations model. For the numerical solution of our aquarium model we apply a low complexity second order

  17. Slow chemical reactions in power plant plumes: application to sulfates

    SciTech Connect

    Forney, L.J.; Giz, Z.G.

    1980-01-01

    Slow chemical reactions in which plume travel time is short compared with characteristic chemical reaction times are incorporated into the MIT buoyant plume theory. Conservation equations are written for a buoyant plume in a crosswind. Approximate solutions to the conservation equations are derived and compared with numerical results. Approximate solutions compared favorably with representative field data. (1 diagram, 4 graphs, 29 references, 1 table)

  18. 40 CFR 721.10193 - 1-Butanaminium, N-(3-aminopropyl)-N-butyl-N-(2-carboxyethyl)-, N-coco acyl derivs., inner salts.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...2-carboxyethyl)-, N-coco acyl derivs., inner salts. 721.10193 Section 721.10193...2-carboxyethyl)-, N-coco acyl derivs., inner salts. (a) Chemical substance and significant...2-carboxyethyl)-, N-coco acyl derivs., inner salts (PMN P-06-263, Chemical B;...

  19. Deriving Darcy's Law

    NSDL National Science Digital Library

    Karen Salvage

    This exercise begins with a demonstration of fluid flow through porous sediment using a constant head permeameter, with the students conducting the experiment and collecting the data. The demo is followed by a Think-Pair-Share exercise in which the question is posed to the class: "What could we change in order to increase flow through the system?" The class then works through their brainstormed list of ideas, discussing each and evaluating whether it is correct or a misconception. The students derive Darcy's Law qualitatively, based upon the results of the Think-Pair-Share exercise and discussions.

  20. Space Derived Air Monitor

    NASA Technical Reports Server (NTRS)

    1983-01-01

    COPAMS, Commonwealth of Pennsylvania Air Monitoring System, derives from technology involved in building unmanned spacecraft. The Nimbus spacecraft carried experimental sensors to measure temperature, pressure, ozone, and water vapor, and instruments for studying solar radiation and telemetry. The process which relayed these findings to Earth formed the basis for COPAMS. The COPAMS system consists of data acquisition units which measure and record pollution level, and sense wind speed and direction, etc. The findings are relayed to a central station where the information is computerized. The system is automatic and supplemented by PAQSS, PA Air Quality Surveillance System.

  1. Quantum chemical 13Calpha chemical shift calculations for protein NMR structure determination, refinement, and validation

    Microsoft Academic Search

    Jorge A. Vila; James M. Aramini; Paolo Rossi; Alexandre Kuzin; Min Su; Jayaraman Seetharaman; Rong Xiao; Liang Tong; Gaetano T. Montelione; Harold A. Scheraga

    2008-01-01

    A recently determined set of 20 NMR-derived conformations of a 48-residue all-alpha-helical protein, (PDB ID code 2JVD), is validated here by comparing the observed 13Calpha chemical shifts with those computed at the density functional level of theory. In addition, a recently introduced physics-based method, aimed at determining protein structures by using NOE-derived distance constraints together with observed and computed 13Calpha

  2. Conversion of lignin biopolymer into surface-active derivatives

    Microsoft Academic Search

    B Koš??ková; M ?uriš; V Demianová

    2000-01-01

    A series of novel lignin-based surface active agents was obtained by alkylation of beechwood prehydrolysis lignin with laurylbromide. Surface tension of measurements of the prepared derivatives revealed that lignin co-product of beechwood prehydrolysis exhibits properties of biodegradable polymeric surfactants after an appropriate chemical modification. All tested modified lignin biopolymers with different degree of alkylation show excellent dispersing and emulsifying efficiency.

  3. Sinaicinone, a complex adamantanyl derivative from Hypericum sinaicum.

    PubMed

    Rezanka, Tomás; Sigler, Karel

    2007-05-01

    The structure of sinaicinone, isolated from the aerial parts of the Egyptian medicinal plant Hypericum sinaicum, has been elucidated by means of spectroscopic data such as UV, IR, MS, 1D and 2D NMR spectra, and chemical degradation. It is a complex adamantanyl derivative with a unique skeleton and oxygenated side chains. PMID:17400263

  4. Adipose-derived cells.

    PubMed

    Meliga, Emanuele; Strem, Brian M; Duckers, H J; Serruys, Patrick W

    2007-01-01

    Heart failure is by far the most common cause of hospitalization in Western countries, with onerous economic consequences. Cell therapy holds great promise for use in tissue regeneration and is increasingly used in an effort to improve outcomes in cardiac disease. Recently it has been shown that adipose tissue, in addition to committed adipogenic, endothelial progenitor cells and pluripotent vascular progenitor cells, also contains multipotent cell types (adipose-derived stem cells, ADSCs) that, in cell culture conditions, have shown to have an impressive developmental plasticity including the ability to undergo multilineage differentiation and self-renewal. ADSCs express multiple CD marker antigens similar to those observed on MSCs and are also capable of secreting a large number of angiogenesis-related cytokines, including vascular endothelial growth factor, granulocyte/macrophage colony stimulating factor, stromal-derived factor-1alpha, and hepatocyte growth factor. Adipose tissue can be harvested in large quantities with minimal morbidity in several regions of the body and, on average, 100 ml of human adipose tissue yields about 1 x 10(6) stem cells. Studies conducted in porcine AMI models have shown a significant LV functional improvement, with no report of any potentially fatal arrhythmias. The APOLLO trial, a prospective, double blind, randomized, placebo-controlled trial currently in the recruiting phase, is a "first-in-man" study that explores the safety and feasibility of ADSC transplantation in patients with acute MI. PMID:18293895

  5. Chemical sensing applications of semiconductor photoluminescence

    NASA Astrophysics Data System (ADS)

    Luebker, Elizabeth R.; Leung, Larry K.; Murphy, Catherine J.; Lisensky, George C.; Ellis, Arthur B.

    1991-05-01

    Semiconductor-derived interfaces have applications in chemical sensing because the bulk photoluminescence (PL) intensity of the semiconductor can be perturbed by chemical adsorption at the surface. Using changes in PL intensity, we have created semiconductor-based systems for non-destructive, in situ, on-line chemical sensing. This paper presents practical applications of PL-based chemical sensors. We have investigated the use of semiconductor PL in a headspace analysis, and in the detection of compounds dissolved in hydrocarbon solution and in aqueous solution. We have constructed two portable systems using semiconductor sensors, where the excitation source, semiconductor, and detection electronics can be transported and used as an on-line system at remote locations. These sensors can be used to detect various classes of compounds in both the liquid and gas phases.

  6. Spithioneines A and B, Two New Bohemamine Derivatives Possessing Ergothioneine Moiety from a Marine-Derived Streptomyces spinoverrucosus.

    PubMed

    Fu, Peng; MacMillan, John B

    2015-06-19

    Spithioneines A and B (1 and 2), two new bohemamine-type pyrrolizidine alkaloids possessing an unusual ergothioneine moiety, were isolated from a marine-derived Streptomyces spinoverrucosus. Their structures were elucidated by spectroscopic analysis, CD spectra, and chemical degradation and synthesis. Compounds 1 and 2 are rare natural products that incorporate the amino acid ergothioneine. PMID:26024315

  7. Helium in Chemically Peculiar Stars

    E-print Network

    F. Leone

    1998-05-05

    For the purpose of deriving the helium abundances in chemically peculiar stars, the importance of assuming a correct helium abundance has been investigated for determining the effective temperature and gravity of main sequence B-type stars, making full use of the present capability of reproducing their helium lines. Even if the flux distribution of main sequence B-type stars appears to depend only on the effective temperature for any helium abundance, the effective temperature, gravity and helium abundance have to be determined simultaneously by matching the Balmer line profiles. New MULTI NLTE calculations, performed adopting ATLAS9 model atmospheres and updated helium atomic parameters, reproduce most of the observed equivalent widths of neutral helium lines for main sequence B-type stars and they make us confident of the possibility to correctly derive the helium abundance in chemically peculiar stars. An application of previous methods to the helium rich star HD 37017 shows that helium could be stratified in the magnetic pole regions, as expected in the framework of the diffusion theory in the presence of mass loss.

  8. 6-Bromocholesterol derivatives

    SciTech Connect

    Flanagan, R.J.

    1984-02-07

    Novel 6-bromo derivatives of cholesterol have the formula 3-(R-O-),6-BR,17-((H3C-)2-HC-H2C-H2C-H2C-HC(-CH3)-)-ESTR-5-ENE Such compounds are prepared from the known 6-iodocholesterol by treatment with cuprous bromide. These compounds, labelled with radioisotopes of Br-82 or Br-77, are localized in the adrenal, mammary and ovary tissue of female mammals and in the adrenal or prostate tissue of males when administered to such individuals. This provides a method for imaging adrenal, ovary or prostate tissue which is superior to use of the prior art 6-iodo-cholesterol.

  9. Chemical and radiation-chemical radical reactions in lignocellulose materials

    NASA Astrophysics Data System (ADS)

    Kuzina, Svetlana I.; Shilova, Irina A.; Mikhailov, Al'fa I.

    2011-09-01

    Chemical and radiation-chemical radical reactions in lignocellulose materials were explored by 3-cm and 2-mm ESR spectroscopy. Background (intrinsic) singlet signals at g=2.003 from wood pulp and lignin and those arising during reaction of lignocellulose materials with acids and chlorine were attributed to radicals with conjugated C?C bonds. The 2-mm ESR signal with 3D anisotropy of g-factor from o-semiquinone radical ions formed in reaction of lignin with NaOH was recorded for the first time. The singlet signals derived from cellulose ?-irradiated at 77 K and marked out during post-thermal reactions were assigned to radicals with conjugated bonds. In wetted cellulose, a triplet signal with ??H?2.7 mT and imposed quadruplet structure (0.5-0.7 mT) from three ?-protons was detected at 300 K and attributed to ? 4-radicals. The triplet signals derived from ? 2- and ? 3-radicals in pyranose cycles of cellulose exhibited higher values of ??H (3.0-3.2 mT) and lower thermal stability (up to 250 K). In radiolyzed cotton pulp, detected were ESR signals derived from formyl radicals formed upon rupture of the ? 5?? 6 bond in pyranose cycles. Heating up irradiated samples under ? 2 was accompanied by formation of peroxide radicals. Photoinduced recombination of trapped electrons with ? 1-radicals was found to proceed as a chain reaction with a kinetic length of about 25 units. Photolysis ( ??360 nm) of radiolyzed cellulose enhanced the disclosure of pyranose cycles and, as a result, the evolution of CO 2 by a factor of 2-2.5.

  10. The first 2(IB),3(IA)-heterodifunctionalized ?-cyclodextrin derivatives as artificial enzymes.

    PubMed

    Letort, S; Mathiron, D; Grel, T; Albaret, C; Daulon, S; Djedaïni-Pilard, F; Gouhier, G; Estour, F

    2015-02-14

    Novel 2,3-heterodisubstituted ?-cyclodextrin derivatives were designed as artificial enzymes to degrade chemical warfare agents. One of them reduced the acetylcholinesterase inhibitory potential by soman faster than its monosubstituted analog. PMID:25572650

  11. Application of quantum-chemical approximations to environmental problems: Prediction of physical and chemical properties of TNT and related species.

    PubMed

    Qasim, Mohammad; Kholod, Yana; Gorb, Leonid; Magers, David; Honea, Patricia; Leszczynski, Jerzy

    2007-10-01

    This paper presents accurate predictions of ecologically important properties of nitroaromatic compounds and their derivatives, including vapor pressure, Henry's law constants, water solubility, octanol/water partition coefficients, heats of formation and ionization potentials. The proposed technique of calculations was based on quantum-chemical methods. The relationship between the chemical structure and mentioned physico-chemical parameters of such widespread military produced contaminants as trinitrotoluene and its derivatives was considered. We revealed that the DFT level of theory combined with the COSMO-RS technique is able to predict the studied parameters with an accuracy that results in error bars of less then one logarithmic unit. PMID:17512030

  12. Deriving Category Theory Type Theory

    E-print Network

    Crole, Roy L.

    Deriving Category Theory from Type Theory Roy L. Crole March 1993 Abstract This work expounds for example [BW90] or [Pie91]. Before we embark on our derivation of a category, let us review the traditional

  13. Capacitive chemical sensor

    DOEpatents

    Manginell, Ronald P; Moorman, Matthew W; Wheeler, David R

    2014-05-27

    A microfabricated capacitive chemical sensor can be used as an autonomous chemical sensor or as an analyte-sensitive chemical preconcentrator in a larger microanalytical system. The capacitive chemical sensor detects changes in sensing film dielectric properties, such as the dielectric constant, conductivity, or dimensionality. These changes result from the interaction of a target analyte with the sensing film. This capability provides a low-power, self-heating chemical sensor suitable for remote and unattended sensing applications. The capacitive chemical sensor also enables a smart, analyte-sensitive chemical preconcentrator. After sorption of the sample by the sensing film, the film can be rapidly heated to release the sample for further analysis. Therefore, the capacitive chemical sensor can optimize the sample collection time prior to release to enable the rapid and accurate analysis of analytes by a microanalytical system.

  14. DTP - Chemical Biology Consortium

    Cancer.gov

    Chemical Biology Consortium Home Discovery Development Pathways Grants/Contracts Books/Publications Site Search Data Search What's New Chemical Biology Consortium (CBC) Division of Cancer Treatment and Diagnosis To download Adobe Reader for documents

  15. Chemical Engineering Division Activities

    ERIC Educational Resources Information Center

    Chemical Engineering Education, 1978

    1978-01-01

    The 1978 ASEE Chemical Engineering Division Lecturer was Theodore Vermeulen of the University of California at Berkeley. Other chemical engineers who received awards or special recognition at a recent ASEE annual conference are mentioned. (BB)

  16. Chemistry 455 Chemical Nanotechnology

    E-print Network

    Rohs, Remo

    Chemistry 455 Chemical Nanotechnology 4 units Prof. Richard Brutchey, Fall 2014 (Lecture = 12:00­12:50 pm MWF) CHEM 455 is an upper-division undergraduate course in Chemical Nanotechnology. The intent

  17. Estimated inventory of chemicals added to underground waste tanks, 1944--1975. [Analysis of sludges and salt cakes

    Microsoft Academic Search

    1976-01-01

    The five major chemical processes, the Bismuth Phosphate process, the Uranium Recovery process, the Redox process, the Purex process, and the Waste Fractionization process have each contributed to give the total Hanford waste chemicals. Each of these processes is studied to determine the total estimated chemicals stored in underground waste tanks. The chemical contents are derived mainly from flowsheet compositions

  18. The elusive chemical potential

    NASA Astrophysics Data System (ADS)

    Baierlein, Ralph

    2001-04-01

    This paper offers some qualitative understanding of the chemical potential, a topic that students invariably find difficult. Three "meanings" for the chemical potential are stated and then supported by analytical development. Two substantial applications—depression of the melting point and batteries—illustrate the chemical potential in action. The origin of the term "chemical potential" has its surprises, and a sketch of the history concludes the paper.

  19. Computing Equilibrium Chemical Compositions

    NASA Technical Reports Server (NTRS)

    Mcbride, Bonnie J.; Gordon, Sanford

    1995-01-01

    Chemical Equilibrium With Transport Properties, 1993 (CET93) computer program provides data on chemical-equilibrium compositions. Aids calculation of thermodynamic properties of chemical systems. Information essential in design and analysis of such equipment as compressors, turbines, nozzles, engines, shock tubes, heat exchangers, and chemical-processing equipment. CET93/PC is version of CET93 specifically designed to run within 640K memory limit of MS-DOS operating system. CET93/PC written in FORTRAN.

  20. Physical and Chemical Change

    NSDL National Science Digital Library

    Mr. Wood

    2010-11-15

    Overview of physical and chemical changes with practice activities and a quiz. Worksheet - Physical Chemical Change Worksheet After viewing the worksheet, copy and paste it into a new blank Google Document - MyDSD Google Login Title your Document "Chemical and Physical Change". Make sure to include your name and period in the body of the doc. The answers in your document should be a different color or font. Examples of Chemical Changes Changes info page More Examples After completing the rest ...

  1. International chemical identifier for chemical reactions

    E-print Network

    Grethe, Guenter; Goodman, Jonathan; Allen, Chad

    2013-03-22

    ORAL PRESENTATION Open Access International chemical identifier for chemical reactions Guenter Grethe1*, Jonathan Goodman2, Chad Allen2 From 8th German Conference on Chemoinformatics: 26 CIC-Workshop Goslar, Germany. 11-13 November 2012 An open... -access software for creating a unique, text-based identifier for reactions (RInChI) was developed by the Goodman group at the University of Cambridge, based on the IUPAC International Chemical Identifier (InChI) stan- dard. RInChIs describe the substances...

  2. HARVARD UNIVERSITY CHEMICAL BIOLOGY

    E-print Network

    Church, George M.

    HARVARD UNIVERSITY CHEMICAL BIOLOGY PHD PROGRAM 2013-2014 Student Handbook #12;Program Contacts at the beginning of each semester. Laboratory Rotations Students in the Chemical Biology Program are expected an interest in having Chemical Biology Program Students in their labs. Students may rotate in the labs

  3. AGRICULTURAL CHEMICAL USAGE DATA

    EPA Science Inventory

    This report, which summarizes the use of agricultural chemicals is issued by the National Agricultural Statistics Service (NASS) as part of its series on Agricultural Chemical Usage. Other publications in the series present statistics for on-farm agricultural chemical usage for f...

  4. Chemicals for worldwide aquaculture

    USGS Publications Warehouse

    Schnick, R.A.

    1991-01-01

    Regulations and therapeutants or other safe chemicals that are approved or acceptable for use in the aquaculture industry in the US, Canada, Europe and Japan are presented, discussing also compounds that are unacceptable for aquaculture. Chemical use practices that could affect public health are considered and details given regarding efforts to increase the number of registered and acceptable chemicals.

  5. Equilibrium Chemical Engines

    E-print Network

    Tatsuo Shibata; Shin-ichi Sasa

    1997-10-30

    An equilibrium reversible cycle with a certain engine to transduce the energy of any chemical reaction into mechanical energy is proposed. The efficiency for chemical energy transduction is also defined so as to be compared with Carnot efficiency. Relevance to the study of protein motors is discussed. KEYWORDS: Chemical thermodynamics, Engine, Efficiency, Molecular machine.

  6. Chemical Kinetic Modeling of Advanced Transportation Fuels

    SciTech Connect

    PItz, W J; Westbrook, C K; Herbinet, O

    2009-01-20

    Development of detailed chemical kinetic models for advanced petroleum-based and nonpetroleum based fuels is a difficult challenge because of the hundreds to thousands of different components in these fuels and because some of these fuels contain components that have not been considered in the past. It is important to develop detailed chemical kinetic models for these fuels since the models can be put into engine simulation codes used for optimizing engine design for maximum efficiency and minimal pollutant emissions. For example, these chemistry-enabled engine codes can be used to optimize combustion chamber shape and fuel injection timing. They also allow insight into how the composition of advanced petroleum-based and non-petroleum based fuels affect engine performance characteristics. Additionally, chemical kinetic models can be used separately to interpret important in-cylinder experimental data and gain insight into advanced engine combustion processes such as HCCI and lean burn engines. The objectives are: (1) Develop detailed chemical kinetic reaction models for components of advanced petroleum-based and non-petroleum based fuels. These fuels models include components from vegetable-oil-derived biodiesel, oil-sand derived fuel, alcohol fuels and other advanced bio-based and alternative fuels. (2) Develop detailed chemical kinetic reaction models for mixtures of non-petroleum and petroleum-based components to represent real fuels and lead to efficient reduced combustion models needed for engine modeling codes. (3) Characterize the role of fuel composition on efficiency and pollutant emissions from practical automotive engines.

  7. Chemical analysis of biomass fast pyrolysis oils

    SciTech Connect

    Elliott, D.C.

    1994-09-01

    This paper reviews the development of the field of chemical analysis of biomass fast pyrolysis oils. The techniques applied to pyrolysis oil analysis are reviewed including proximate and ultimate analysis, water (moisture) analysis, and chemical component analysis by various forms of chromatography, solvent separations, and spectrophotometric analyses, like infrared and ultraviolet. Advanced analytical techniques such as nuclear magnetic resonance and molecular beam -- mass spectrometry are also discussed. This paper reviews and compares the methods and the results of the analyses. The advantages and shortcomings of the various methods applied are identified. Comparisons derived from the IEA Round Robin are incorporated.

  8. Chemistry Review: Chemical Change

    NSDL National Science Digital Library

    James Kessler

    2010-01-01

    This review provides many details about chemical reactions and the components involved in order to make one happen, such as energy, heat, density, and substance. Provided are animations that show molecular combustion that occurs with a chemical reaction. The role of atoms is also described, including Ionic bonds that occur or break in a chemical reaction. Simple experiments use substances such as vinegar, water, and baking soda to show a real chemical reaction in progress. Temperature change in chemical reactions is explained in detail, along with endothermic and exothermic reactions.

  9. TECHNICAL BASIS FOR NARCOTIC CHEMICALS AND POLYCYCLIC AROMATIC HYDROCARBON CRITERIA. II. MIXTURES AND SEDIMENTS

    Microsoft Academic Search

    Dominic M. Di Toro; Joy A. McGrath

    2000-01-01

    A method is presented for developing sediment quality guidelines (SQG) for narcotic chemicals in general and polycyclic aromatic hydrocarbons (PAHs) in particular. The guidelines can be applied to any individual or mixture of narcotic chemicals including PAHs using only the chemical's octanol\\/water partition coefficient. They are derived using the final chronic values for type I narcotics developed from a database

  10. Chemical component mapping of pulverized toner by scanning transmission X-ray microscopy

    E-print Network

    Hitchcock, Adam P.

    and resin environments through chemical component maps derived from multiple energy image sequences achieves strong chemical sensitivity through near edge X-ray absorption spectral (NEXAFS) contrast (StoChemical component mapping of pulverized toner by scanning transmission X-ray microscopy Noriyuki

  11. Operational degradation of organic light-emitting diodes: Mechanism and identification of chemical products

    Microsoft Academic Search

    D. Y. Kondakov; W. C. Lenhart; W. F. Nichols

    2007-01-01

    Despite the importance of the operational lifetime of organic light-emitting diodes (OLEDs) in practical applications, little is known about the nature of chemical reactions associated with efficiency losses during operation. To gain an insight into a chemical mechanism of operational degradation, we studied operation-induced changes in chemical compositions of fluorescent and phosphorescent OLEDs utilizing carbazole derivatives in emissive layers. We

  12. Rapid biomass analysis: New analytical methods supporting fuels and chemical production from biomass

    Microsoft Academic Search

    Bonnie R. Hames; Amie D. Sluiter; Chris J. Roth; Robert R. Meglen

    The ability to obtain an accurate chemical composition of biomass and biomass-derived samples using rapid and inexpensive methods is a key element supporting commercialization of processes that convert biomass to fuels and chemicals. The development and demonstrated use of rapid analysis methods for chemical characterization of feedstocks, process intermediates and solid residues will be presented. The new techniques being presented

  13. Bioremediation of subsurface sediment and groundwater contaminated with pyridine and pyridine derivatives

    Microsoft Academic Search

    Ronen

    1992-01-01

    The presence of toxic organic chemicals such as pyridine and its alkyl derivatives, found in groundwater as a consequence of industrial activities, present a direct hazard to human health and to the environment. The toxicity of these compounds, their teratogenic properties, and their irritating odor require urgent remediation. Physical, chemical, and biological treatments are commonly applied for the removal of

  14. Chemical exchange program analysis.

    SciTech Connect

    Waffelaert, Pascale

    2007-09-01

    As part of its EMS, Sandia performs an annual environmental aspects/impacts analysis. The purpose of this analysis is to identify the environmental aspects associated with Sandia's activities, products, and services and the potential environmental impacts associated with those aspects. Division and environmental programs established objectives and targets based on the environmental aspects associated with their operations. In 2007 the most significant aspect identified was Hazardous Materials (Use and Storage). The objective for Hazardous Materials (Use and Storage) was to improve chemical handling, storage, and on-site movement of hazardous materials. One of the targets supporting this objective was to develop an effective chemical exchange program, making a business case for it in FY07, and fully implementing a comprehensive chemical exchange program in FY08. A Chemical Exchange Program (CEP) team was formed to implement this target. The team consists of representatives from the Chemical Information System (CIS), Pollution Prevention (P2), the HWMF, Procurement and the Environmental Management System (EMS). The CEP Team performed benchmarking and conducted a life-cycle analysis of the current management of chemicals at SNL/NM and compared it to Chemical Exchange alternatives. Those alternatives are as follows: (1) Revive the 'Virtual' Chemical Exchange Program; (2) Re-implement a 'Physical' Chemical Exchange Program using a Chemical Information System; and (3) Transition to a Chemical Management Services System. The analysis and benchmarking study shows that the present management of chemicals at SNL/NM is significantly disjointed and a life-cycle or 'Cradle-to-Grave' approach to chemical management is needed. This approach must consider the purchasing and maintenance costs as well as the cost of ultimate disposal of the chemicals and materials. A chemical exchange is needed as a mechanism to re-apply chemicals on site. This will not only reduce the quantity of unneeded chemicals and the amount spent on new purchases, but will also avoid disposal costs. If SNL/NM were to realize a 5 percent reduction in chemical inventory and a 10 percent reduction in disposal of unused chemicals the total savings would be $189, 200 per year.

  15. Correlation between model-calculated anthropogenic aerosols and satellite-derived cloud optical depths: Indication of indirect effect?

    Microsoft Academic Search

    W. L. Chameides; C. Luo; R. Saylor; D. Streets; Y. Huang; M. Bergin; F. Giorgi

    2002-01-01

    We consider two independently derived data sets. The first represents the annually averaged distribution of anthropogenic aerosols over East Asia as derived by a coupled regional climate\\/chemical transport model. The other is the annually averaged distributions of cloud optical depths and cloud amount over East Asia derived by the International Satellite Cloud Climatology Project (ISCCP) for 1990, 1991, 1992, and

  16. 40 CFR 721.1225 - Benzene, 1,2-dimethyl-, poly-propene derivatives, sulfonated, po-tas-sium salts.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...derivatives, sulfonated, po-tas-sium salts. 721.1225 Section 721.1225 Protection...derivatives, sulfonated, po-tas-sium salts. (a) Chemical substances and significant...polypropene derivatives, sulfonated, potassium salts (PMN P-89-711) is subject to...

  17. 40 CFR 721.1225 - Benzene, 1,2-dimethyl-, poly-propene derivatives, sulfonated, po-tas-sium salts.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...derivatives, sulfonated, po-tas-sium salts. 721.1225 Section 721.1225 Protection...derivatives, sulfonated, po-tas-sium salts. (a) Chemical substances and significant...polypropene derivatives, sulfonated, potassium salts (PMN P-89-711) is subject to...

  18. 40 CFR 721.1225 - Benzene, 1,2-dimethyl-, poly-propene derivatives, sulfonated, po-tas-sium salts.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...derivatives, sulfonated, po-tas-sium salts. 721.1225 Section 721.1225 Protection...derivatives, sulfonated, po-tas-sium salts. (a) Chemical substances and significant...polypropene derivatives, sulfonated, potassium salts (PMN P-89-711) is subject to...

  19. Thermoelastic constitutive equations for chemically hardening materials

    NASA Technical Reports Server (NTRS)

    Shaffer, B. W.; Levitsky, M.

    1974-01-01

    Thermoelastic constitutive equations are derived for a material undergoing solidification or hardening as the result of a chemical reaction. The derivation is based upon a two component model whose composition is determined by the degree of hardening, and makes use of strain-energy considerations. Constitutive equations take the form of stress rate-strain rate relations, in which the coefficients are time-dependent functions of the composition. Specific results are developed for the case of a material of constant bulk modulus which undergoes a transition from an initial liquidlike state into an isotropic elastic solid. Potential applications are discussed.

  20. Highly Hazardous Chemicals and Chemical Spills EPA Compliance Fact Sheet

    E-print Network

    Wikswo, John

    Highly Hazardous Chemicals and Chemical Spills EPA Compliance Fact Sheet Vanderbilt Environmental.safety.vanderbilt.edu HIGHLY HAZARDOUS CHEMICAL WASTES Certain chemical wastes must be handled by special procedures due to their highly hazardous nature. These chemicals include expired isopropyl and ethyl ethers (these chemicals

  1. [Inulin and derivates as key ingredients in functional foods].

    PubMed

    Madrigal, Lorena; Sangronis, Elba

    2007-12-01

    Inulin is a non-digestible carbohydrate that is contained in many vegetables, fruits and cereals. It is industrially produced from the chicory's root (Cichorium intybus) and it is widely used as ingredient in functional foods. Inulin and its derivate compounds (oligofructose, fructooligosaccharides) are usually called fructans, as they are basically based on linear fructose chains. This review presents a description of inulin and its most common derivate compounds: chemical structure, natural sources, physic-chemical properties, technological functionality, industrial manufacturing, analytical method for determination and health benefits: prebiotic, dietary fiber, low caloric value, hypoglycemic action, enhancement of calcium and magnesium bioavailability. Potential benefits: lipid parameters regulation, reduction of colon cancer risk and others, improvement of immune response, intestinal disorders protection. From technological point of view, these compounds exhibit a variety of properties: thickener, emulsifier, gel forming, sugar and fat substitute, humectant, freezing point depression. Inulin and derivates are been used in pharmaceutical, chemical and processing industry as technological additives and excipients. They are also been used for animal feeding. They are been considered as "bioactive" compounds to be proposed as future packaging material. Fructans are proposed to be classified as "functional fiber", according to recent concepts based on physiological effects on individuals. This review of inulin and its derivates was useful to show the broad boundaries of these compounds in the food industry and why they may be considered as key ingredients in the expanding functional food market. PMID:18524324

  2. Chitooligosaccharide and Its Derivatives: Preparation and Biological Applications

    PubMed Central

    Lodhi, Gaurav; Hwang, Jin-Woo; Kim, Se-Kwon; Jeon, You-Jin; Je, Jae-Young; Ahn, Chang-Bum; Moon, Sang-Ho; Jeon, Byong-Tae; Park, Pyo-Jam

    2014-01-01

    Chitin is a natural polysaccharide of major importance. This biopolymer is synthesized by an enormous number of living organisms; considering the amount of chitin produced annually in the world, it is the most abundant polymer after cellulose. The most important derivative of chitin is chitosan, obtained by partial deacetylation of chitin under alkaline conditions or by enzymatic hydrolysis. Chitin and chitosan are known to have important functional activities but poor solubility makes them difficult to use in food and biomedicinal applications. Chitooligosaccharides (COS) are the degraded products of chitosan or chitin prepared by enzymatic or chemical hydrolysis of chitosan. The greater solubility and low viscosity of COS have attracted the interest of many researchers to utilize COS and their derivatives for various biomedical applications. In light of the recent interest in the biomedical applications of chitin, chitosan, and their derivatives, this review focuses on the preparation and biological activities of chitin, chitosan, COS, and their derivatives. PMID:24724091

  3. Marine-Derived Angiogenesis Inhibitors for Cancer Therapy

    PubMed Central

    Wang, Ying-Qing; Miao, Ze-Hong

    2013-01-01

    Angiogenesis inhibitors have been successfully used for cancer therapy in the clinic. Many marine-derived natural products and their analogues have been reported to show antiangiogenic activities. Compared with the drugs in the clinic, these agents display interesting characteristics, including diverse sources, unique chemical structures, special modes of action, and distinct activity and toxicity profiles. This review will first provide an overview of the current marine-derived angiogenesis inhibitors based on their primary targets and/or mechanisms of action. Then, the marine-derived antiangiogenic protein kinase inhibitors will be focused on. And finally, the clinical trials of the marine-derived antiangiogenic agents will be discussed, with special emphasis on their application potentials, problems and possible coping strategies in their future development as anticancer drugs. PMID:23502698

  4. Preparation and characterization of a quaternary ammonium derivative of konjac glucomannan

    Microsoft Academic Search

    Huiqun Yu; Yihong Huang; Hou Ying; Chaobo Xiao

    2007-01-01

    Cationic derivatives of konjac glucomannan (KGM) were prepared by reacting KGM with 3-chloro-2-hydroxypropyltrimethylammonium chloride (CHPTAC) in presence of sodium hydroxide. The chemical structures of derivative were characterized by use of elemental analysis, FTIR and 13C NMR spectroscopy and static light scattering technique. The results revealed that the degree of substitution (DS) of quaternized konjac glucomannan (QKGM) could be controlled by

  5. Decay resistance of wood treated with boric acid and tall oil derivates

    Microsoft Academic Search

    Ali Temiz; Gry Alfredsen; Morten Eikenes; Nasko Terz?ev

    2008-01-01

    In this study, the effect of two boric acid concentrations (1% and 2%) and four derivates of tall oil with varying chemical composition were tested separately and in combination. The tall oil derivates were chosen in a way that they consist of different amounts of free fatty, resin acids and neutral compounds. Decay tests using two brown rot fungi (Postia

  6. Derivation of the Second Law of Thermodynamics from Boltzmann's Distribution Law.

    ERIC Educational Resources Information Center

    Nelson, P. G.

    1988-01-01

    Shows how the thermodynamic condition for equilibrium in an isolated system can be derived by the application of Boltzmann's law to a simple physical system. States that this derivation could be included in an introductory course on chemical equilibrium to help prepare students for a statistical mechanical treatment presented in the curriculum.…

  7. Isolation and characterization of melanic pigments derived from tea and tea polyphenols

    Microsoft Academic Search

    Vasyl M. Sava; Swen-Ming Yang; Meng-Yen Hong; Ping-Cheng Yang; Guewha Steven Huang

    2001-01-01

    The dark brown pigments derived from tea and tea polyphenols were studied. Physical and chemical properties revealed that pigments directly extracted from tea leaves and derived from tea polyphenols were similar to typical melanins. Further investigation showed that both melanic pigments possessed similar antioxidant capability, due to their chelating and scavenging properties. The inhibitory effect of melanic pigments, either from

  8. ALTERNATIVE FUELS AND CHEMICALS FROM SYNTHESIS GAS

    SciTech Connect

    Unknown

    1998-01-01

    The overall objectives of this program are to investigate potential technologies for the conversion of synthesis gas to oxygenated and hydrocarbon fuels and industrial chemicals, and to demonstrate the most promising technologies at DOE's LaPorte, Texas, Slurry Phase Alternative Fuels Development Unit (AFDU). The program will involve a continuation of the work performed under the Alternative Fuels from Coal-Derived Synthesis Gas Program and will draw upon information and technologies generated in parallel current and future DOE-funded contracts.

  9. Hand chemical burns.

    PubMed

    Robinson, Elliot P; Chhabra, A Bobby

    2015-03-01

    There is a vast and ever-expanding variety of potentially harmful chemicals in the military, industrial, and domestic landscape. Chemical burns make up a small proportion of all skin burns, yet they can cause substantial morbidity and mortality. Additionally, the hand and upper extremity are the most frequently involved parts of the body in chemical burns, and therefore these injuries may lead to severe temporary or permanent loss of function. Despite this fact, discussion of the care of these injuries is sparse in the hand surgery literature. Although most chemical burns require only first response and wound care, some require the attention of a specialist for surgical debridement and, occasionally, skin coverage and reconstruction. Exposure to certain chemicals carries the risk of substantial systemic toxicity and even mortality. Understanding the difference between thermal and chemical burns, as well as special considerations for specific compounds, will improve patient treatment outcomes. PMID:25653184

  10. Toxic Chemical System (TCS)

    SciTech Connect

    Del Gandio, P.

    1994-09-01

    The Toxic Chemical System (TCS) will have the capacity to process chemical data, calculate chemical formulas, and format the data into the United States (US) Environmental Protection Agency (EPA) Toxic Chemical Release Inventory Reporting Form R of Section 313 of the Emergency Planning and Community Right-to-Know Act (EPCRA), hereafter be referred to as ``Form R.`` The filing of this form is required of all industries which manufacture, process or otherwise use any EPA listed chemicals in quantities in excess of their threshold planning quantities (TPQ). Facilities required to file the Form R must report the quantities of both routine and accidental releases of listed toxic chemicals on-site during the calendar year and the amount contained in waste products transferred off-site. This paper describes a specialized computer system designed for regulatory compliance.

  11. Journal of Chemical Education: Chemical Resource Shelf

    NSDL National Science Digital Library

    1995-01-01

    Produced under the auspices of the Journal of Chemical Education Online, this site is the basis for that journal's "Book Buyer's Guide." It provides high school and college-level chemistry educators with various teaching resources, including a comprehensive index to chemistry textbooks in print. The index is arranged by subject, under which entries are listed in chronological order, from newest to oldest. Subjects covered range from Biochemistry and Computers in Chemistry to Quantum Chemistry and Writing in Science. In addition to basic bibliographic information, when available, each entry includes citations of reviews and links to publishers' online catalogs. Another feature is "Hal's Picks of the Month," a growing archive of over 30 "books and recent articles for teachers of chemistry and related sciences" as recommended and reviewed by Professor Harold (Hal) Harris of the University of Missouri - St. Louis Chemistry Department. "Journals of Interest to Chemical Educators" and "Suppliers of Software for Chemical Education" are two other lists available at this site.

  12. Excimer laser chemical problems

    SciTech Connect

    Tennant, R.; Peterson, N.

    1982-01-01

    Techniques need to be developed to maintain XeF and XeCl laser performance over long periods of time without degradation resulting from chemical processes occurring within the laser. The dominant chemical issues include optical damage, corrosions of laser materials, gas contamination, and control of halogen concentration. Each of these issues are discussed and summarized. The methods of minimizing or controlling the chemical processes involved are presented.

  13. In Vitro and In Vivo Cytotoxicities and Antileishmanial Activities of Thymol and Hemisynthetic Derivatives

    Microsoft Academic Search

    Sara Robledo; Edison Osorio; Diana Munoz; Luz Marina Jaramillo; Adriana Restrepo; Gabriel Arango; Ivan Velez

    2005-01-01

    Thymol, a p-cymene-derived compound, is widely used in medicine for its antimicrobial, antiseptic, disinfectant, and wound-healing properties (1, 3, 6, 10, 12, 16). Because deriv- atives of p-cymene have leishmanicidal activity (2, 8, 11) and are considered important basic structures for development of novel antiparasitic drugs (9), in this study the thymol structure was chemically modified and its derivated were

  14. Biomolecule derived nanostructured arrays

    NASA Astrophysics Data System (ADS)

    Yuan, Zhen

    During the last decade, intensive research have been reported on biomimetic approaches towards achieving mono-dispersed nanoparticles, and building self-assembled system out of those (organizing nanoparticles). However the development of this research avenue is being hindered by the limited knowledge and very few practical, efficient, cost-effective approaches for implementation of the bio-derived arrays into engineering practice. The objective of this work is to biomimeticaly form nanocomposite materials using a simple, rapid, inexpensive, scalable approach, which is general enough and not limited to colloidal particle self-assembly. Throughout the studies, we have developed a universally applicable process, which is to fabricate macro-biomolecular arrays on solid substrates based on the convective self-assembly of colloidal particles. We have demonstrated that protein (ferritin) and virus (phage) arrays were directly deposited onto solid substrates such as glass, silicon wafer, and gold substrate in closed or near closed-packed order. The arrays were further incorporated into a more robust silica matrix, in such that strengthens the thermal stability and provides porous accessibility. After treatment in controlled pyrolysis, the organic protein shell was removed, left mono-dispersed iron-oxide nanoparticles intact on the substrate or in the silica matrix. Both iron-oxide nanoparticles arrays with or without silica matrix have been further characterized to possess superferromagnetic properties at low temperature (15 K), same as that in bulk material. Initial work on protein patterning, through combining either lithography based top-down or bottom-up techniques with our novel deposition approach, was presented as well. Thin film deposition of mesoporous materials using convective self-assembly is another main part in this work. Both silica and carbon mesoporous thin films were successfully formed using the convective self-assembly horizontal-coating approach. We have shown that ultra thin mesoporous film (less than 100 nm) could be obtained through increasing the coating speed with the solution concentration remained same. Combining with lithographically patterned surface, the mesoporous thin films will be well suited for applications for bio-sensing, separations and etc. Studies were also carried out on the transport of fluid and electric current in fluidic channels with size in nanometer range; particular attention was paid on the effect of the electrolyte valence. At these dimensions new physical phenomena begin to occur because the electric double layers formed at the channel walls become comparable to the channel width and the overall wall surface to channel volume ratio increases. Numerical analysis predicts that the electrokinetic transport phenomena differ from multivalent ions to monovalent ions in the nanochannel when double layer overlap is large. This dependence affects the transport of current, fluid and dissolved analytes in a fluidic channel. The valence of the dissolved counterions determines the electric current and fluid flow in a nanochannel by shaping the electrostatic potential distribution. Our calculation shows that in absence of strong adsorption at the wall, divalent counterions lead to greater current and fluid flow than monovalent electrolyte for the same overall ionic strength. The results also indicate that control over the transport processes in fluidic nanochannels can be accomplished through properly selecting and combining electrolytes.

  15. Apparatus for chemical synthesis

    DOEpatents

    Kong, Peter C. (Idaho Falls, ID); Herring, J. Stephen (Idaho Falls, ID); Grandy, Jon D. (Idaho Falls, ID)

    2011-05-10

    A method and apparatus for forming a chemical hydride is described and which includes a pseudo-plasma-electrolysis reactor which is operable to receive a solution capable of forming a chemical hydride and which further includes a cathode and a movable anode, and wherein the anode is moved into and out of fluidic, ohmic electrical contact with the solution capable of forming a chemical hydride and which further, when energized produces an oxygen plasma which facilitates the formation of a chemical hydride in the solution.

  16. Physical and Chemical Changes

    NSDL National Science Digital Library

    Mrs. Holly

    2010-11-15

    Physical and chemical changes in matter affect us every day. Use the following resources to help you understand these changes more completely. Read this document to help you understand the difference between physical and chemical changes in matter. definitions Watch this! It illustrates the physical change of matter. physical change video Now, watch this! It illustrates the chemical change of matter. chemical change video Click on this link to read and explore the Utah Science Sci-ber Site. It will help you to ...

  17. Field emission chemical sensor

    DOEpatents

    Panitz, J.A.

    1983-11-22

    A field emission chemical sensor for specific detection of a chemical entity in a sample includes a closed chamber enclosing two field emission electrode sets, each field emission electrode set comprising (a) an electron emitter electrode from which field emission electrons can be emitted when an effective voltage is connected to the electrode set; and (b) a collector electrode which will capture said electrons emitted from said emitter electrode. One of the electrode sets is passive to the chemical entity and the other is active thereto and has an active emitter electrode which will bind the chemical entity when contacted therewith.

  18. Overview of medically important antifungal azole derivatives.

    PubMed Central

    Fromtling, R A

    1988-01-01

    Fungal infections are a major burden to the health and welfare of modern humans. They range from simply cosmetic, non-life-threatening skin infections to severe, systemic infections that may lead to significant debilitation or death. The selection of chemotherapeutic agents useful for the treatment of fungal infections is small. In this overview, a major chemical group with antifungal activity, the azole derivatives, is examined. Included are historical and state of the art information on the in vitro activity, experimental in vivo activity, mode of action, pharmacokinetics, clinical studies, and uses and adverse reactions of imidazoles currently marketed (clotrimazole, miconazole, econazole, ketoconazole, bifonazole, butoconazole, croconazole, fenticonazole, isoconazole, oxiconazole, sulconazole, and tioconazole) and under development (aliconazole and omoconazole), as well as triazoles currently marketed (terconazole) and under development (fluconazole, itraconazole, vibunazole, alteconazole, and ICI 195,739). PMID:3069196

  19. Fluorescein Derivatives in Intravital Fluorescence Imaging

    PubMed Central

    Robertson, Thomas A.; Bunel, Florestan; Roberts, Michael S.

    2013-01-01

    Intravital fluorescence microscopy enables the direct imaging of fluorophores in vivo and advanced techniques such as fluorescence lifetime imaging (FLIM) enable the simultaneous detection of multiple fluorophores. Consequently, it is now possible to record distribution and metabolism of a chemical in vivo and to optimise the delivery of fluorophores in vivo. Recent clinical applications with fluorescein and other intravital fluorescent stains have occurred in neurosurgery, dermatology [including photodynamic therapy (PDT)] and endomicroscopy. Potential uses have been identified in periodontal disease, skin graft and cancer surgery. Animal studies have demonstrated that diseased tissue can be specifically stained with fluorophore conjugates. This review focuses on the fluorescein derived fluorophores in common clinical use and provides examples of novel applications from studies in tissue samples. PMID:24709799

  20. Synthesis and conformational analysis of naphthylnaphthoxazine derivatives

    NASA Astrophysics Data System (ADS)

    Tóth, Diána; Szatmári, István; Heydenreich, Matthias; Koch, Andreas; Kleinpeter, Erich; Fülöp, Ferenc

    2009-07-01

    Four new primary aminonaphthols ( 4, 5, 9 and 10) were synthesized from 1- or 2-naphthol and 1- or 2-naphthaldehyde via naphthoxazines in modified Mannich condensations. Simple ring-closure reactions of these aminonaphthols with paraformaldehyde, 4-nitrobenzaldehyde, phosgene or 4-chlorophenyl isothiocyanate led to new heterocyclic derivatives. In these transformations, either an sp 2 or an sp 3 carbon was inserted between the hydroxy and amino groups. The effects of substituents and the naphthyl ring on the conformation were investigated by means of NMR measurements, employing both dipolar and scalar couplings. The structures were confirmed by DFT quantum chemical calculations involving computed coupling constants, intramolecular distances between nuclei and the relative energies of the preferred conformers.

  1. A quinozolinone derivative as a novel rubber additive

    SciTech Connect

    Roy, B.C.; Khanra, T.K.; Maiti, S.; Adhikari, B. [Indian Institute of Technology, Kharagpur (India)

    1993-12-31

    A new quinozolinone derivative containing -NH and -SH functional sites has been developed as a novel antioxidant for diene rubbers. A sulfenamide derivative was prepared from the above compound which acts as an excellent accelerator cum antioxidant for natural rubber. This sulfenamide compound even when used at 50% concentration of the combined amount of commercial accelerator (CBS) and antioxidant (MBI) exhibits comparable accelerating characteristics and superior antiaging performance in the vulcanization of natural rubber. This dual function sulfenamide promises to offer better dispersion in the rubber matrix than two separate chemicals - one accelerator and the other antioxidant - used commercially.

  2. Programmed Derivations of Relational Structures

    Microsoft Academic Search

    Andrea Maggiolo-schettini; Józef Winkowski

    1990-01-01

    Derivations of relational structures by applying productions are considered. The corresponding concepts are taken from the existing algebraic (category theory) approach to transformations of relational structures. An idea of programs for defining sets of derivations is introduced. A number of programming constructs is introduced to specify applications of productions in a controlled way. These constructs are given together with two

  3. Pseudorandom Financial Derivatives [Extended Abstract

    E-print Network

    Zuckerman, David

    in the recent financial crisis. A derivative is a financial product whose value is a function of one or more un computational assumption. In- deed, in the recent financial crisis, it appears that sellers did pack lemonsPseudorandom Financial Derivatives [Extended Abstract] David Zuckerman Department of Computer

  4. Inflation Derivatives L. P. Hughston

    E-print Network

    Macrina, Andrea

    Inflation Derivatives L. P. Hughston Department of Mathematics King's College London The Strand (0)207 848 2855 Abstract. A general theory for the pricing and hedging of inflation The purpose of this note is to outline briefly a general model of inflation and inflation-linked derivatives

  5. Elementary derivation of Kepler's laws

    Microsoft Academic Search

    Erich Vogt

    1996-01-01

    A simple derivation of all three so-called Kepler laws is presented in which the orbits, bound and unbound, follow directly and immediately from conservation of energy and angular momentum. The intent is to make this crowning achievement of Newtonian mechanics easily accessible to students in introductory physics courses. The method is also extended to simplify the derivation of the Rutherford

  6. How accurate are the nonlinear chemical Fokker-Planck and chemical Langevin equations?

    NASA Astrophysics Data System (ADS)

    Grima, Ramon; Thomas, Philipp; Straube, Arthur V.

    2011-08-01

    The chemical Fokker-Planck equation and the corresponding chemical Langevin equation are commonly used approximations of the chemical master equation. These equations are derived from an uncontrolled, second-order truncation of the Kramers-Moyal expansion of the chemical master equation and hence their accuracy remains to be clarified. We use the system-size expansion to show that chemical Fokker-Planck estimates of the mean concentrations and of the variance of the concentration fluctuations about the mean are accurate to order ?-3/2 for reaction systems which do not obey detailed balance and at least accurate to order ?-2 for systems obeying detailed balance, where ? is the characteristic size of the system. Hence, the chemical Fokker-Planck equation turns out to be more accurate than the linear-noise approximation of the chemical master equation (the linear Fokker-Planck equation) which leads to mean concentration estimates accurate to order ?-1/2 and variance estimates accurate to order ?-3/2. This higher accuracy is particularly conspicuous for chemical systems realized in small volumes such as biochemical reactions inside cells. A formula is also obtained for the approximate size of the relative errors in the concentration and variance predictions of the chemical Fokker-Planck equation, where the relative error is defined as the difference between the predictions of the chemical Fokker-Planck equation and the master equation divided by the prediction of the master equation. For dimerization and enzyme-catalyzed reactions, the errors are typically less than few percent even when the steady-state is characterized by merely few tens of molecules.

  7. Intra- and intermolecular hydrogen bonding in acetylacetone and benzoylacetone derived enaminone derivatives

    NASA Astrophysics Data System (ADS)

    Lazi?, Vedrana; Jurkovi?, Mihaela; Jedna?ak, Tomislav; Hrenar, Tomica; Vukovi?, Jelena Parlov; Novak, Predrag

    2015-01-01

    The structure and hydrogen bonding in solution of acetylacetone and benzoylacetone derived enaminone derivatives, 1a-1d and 2a-2d, have been studied by a combination of experimental (NMR and UV spectroscopies) and theoretical (PM6 and DFT) methods. It has been shown that all studied compounds predominantly existed in the localised keto-amine tautomeric form in solution as found also in the solid state. Significant line-broadening and down-field chemical shifts of NH and OH protons have strongly indicated that both groups formed hydrogen bonds, which has further been supported by quantum chemical calculations. Temperature and concentration dependent NMR measurements have pointed towards the fact that NH protons are engaged in strong intramolecular hydrogen bonds of the NH⋯Odbnd C type in both solvents. On the other hand, OH protons are involved in weaker intermolecular hydrogen bonding with solvent molecules in DMSO, while in chloroform intermolecular interactions between two molecules dominate. The results presented in this paper can be used for better understanding and further exploiting properties these ligands possess, especially their bioactivity.

  8. Synthesis and antibacterial activity evaluation of two androgen derivatives.

    PubMed

    Lauro, Figueroa-Valverde; Francisco, Díaz-Cedillo; Elodia, García-Cervera; Eduardo, Pool-Gómez; Maria, López-Ramos; Marcela, Rosas-Nexticapa; Lenin, Hau-Heredia; Bety, Sarabia-Alcocer

    2015-01-01

    In this study two androgen derivatives were synthesized using several strategies; the first stage an aza-steroid derivative (3) was developed by the reaction of a testosterone derivative (1) with thiourea (2) in presence of hydrogen chloride. The second step, involves the synthesis of an amino-steroid derivative (4) by the reaction of 1 with 2 using boric acid as catalyst. The third stage was achieved by the preparation of an aminoaza-androgen derivative (6) by the reaction of 3 with ethylenediamine using boric acid as catalyst. In addition, the compound 6 was made reacting with dihydrotestosterone to form a new androgen derivative (7) in presence of boric acid. The following step was achieved by the reaction of 7 with chloroacetyl chloride to synthesize an azetidinone-androgen derivative (8) using triethylamine as catalyst. Additionally, a thiourea-androgen derivative (9) was synthetized by the reaction of 4 with dihydrotestosterone using boric acid as catalyst. Finally, the compound 9 was made reacting with chloroacetyl chloride in presence of triethylamine to synthesize a new azetidinone-androgen derivative (10). On the other hand, antibacterial activity of compounds synthesized was evaluated on Gram negative (Escherichia coli and Vibrio cholerae) and Gram positive (Staphylococos aureus) bacteria. The results indicate that only the compound 3 and 8 decrease the growth bacterial of E. coli and V. cholerae. Nevertheless, growth bacterial of S. aureus was not inhibited by these compounds. These data indicate that antibacterial activity exerted by the compounds 3 and 8 depend of their structure chemical in comparison with the controls and other androgen derivatives that are involved in this study. PMID:25448363

  9. Derivations and skew derivations of the Grassmann algebras

    E-print Network

    Bavula, V V

    2007-01-01

    Surprisingly, skew derivations rather than ordinary derivations are more basic (important) object in study of the Grassmann algebras. Let $\\L_n = K\\lfloor x_1, ..., x_n\\rfloor$ be the Grassmann algebra over a commutative ring $K$ with ${1/2}\\in K$, and $\\d$ be a skew $K$-derivation of $\\L_n$. It is proved that $\\d$ is a unique sum $\\d = \\d^{ev} +\\d^{od}$ of an even and odd skew derivation. Explicit formulae are given for $\\d^{ev}$ and $\\d^{od}$ via the elements $\\d (x_1), ..., \\d (x_n)$. It is proved that the set of all even skew derivations of $\\L_n$ coincides with the set of all the inner skew derivations. Similar results are proved for derivations of $\\L_n$. In particular, $\\Der_K(\\L_n)$ is a faithful but not simple $\\Aut_K(\\L_n)$-module (where $K$ is reduced and $n\\geq 2$). All differential and skew differential ideals of $\\L_n$ are found. It is proved that the set of generic normal elements of $\\L_n$ that are not units forms a single $\\Aut_K(\\L_n)$-orbit (namely, $\\Aut_K(\\L_n)x_1$) if $n$ is even and two...

  10. Derivations and skew derivations of the Grassmann algebras

    E-print Network

    V. V. Bavula

    2007-04-29

    Surprisingly, skew derivations rather than ordinary derivations are more basic (important) object in study of the Grassmann algebras. Let $\\L_n = K\\lfloor x_1, ..., x_n\\rfloor$ be the Grassmann algebra over a commutative ring $K$ with ${1/2}\\in K$, and $\\d$ be a skew $K$-derivation of $\\L_n$. It is proved that $\\d$ is a unique sum $\\d = \\d^{ev} +\\d^{od}$ of an even and odd skew derivation. Explicit formulae are given for $\\d^{ev}$ and $\\d^{od}$ via the elements $\\d (x_1), ..., \\d (x_n)$. It is proved that the set of all even skew derivations of $\\L_n$ coincides with the set of all the inner skew derivations. Similar results are proved for derivations of $\\L_n$. In particular, $\\Der_K(\\L_n)$ is a faithful but not simple $\\Aut_K(\\L_n)$-module (where $K$ is reduced and $n\\geq 2$). All differential and skew differential ideals of $\\L_n$ are found. It is proved that the set of generic normal elements of $\\L_n$ that are not units forms a single $\\Aut_K(\\L_n)$-orbit (namely, $\\Aut_K(\\L_n)x_1$) if $n$ is even and two orbits (namely, $\\Aut_K(\\L_n)x_1$ and $\\Aut_K(\\L_n)(x_1+x_2... x_n)$) if $n$ is odd.

  11. CHEMICAL CATEGORIES IN EPA'S NEW CHEMICALS PROGRAM

    EPA Science Inventory

    Under section 5 of the Toxic Substances Control Act (TSCA),any person who intends to manufacture or import a new chemical substance, or mixture containing such a substance, in the United States for commercial purposes must submit a premanufacture notice (PMN) to the Environmental...

  12. Chemical Evolution in the LMC

    NASA Astrophysics Data System (ADS)

    Dirsch, B.; Richtler, T.; Gieren, W. P.

    We present preliminary results of an ongoing programme, measuring ages and metallicities of red giants in the Large Magellanic Cloud (LMC) on the basis of Strömgren photometry (Dirsch, Richtler, Gieren 1999, submitted to A&A). Since age and metallicity determinations through Strömgren photometry are (almost) decoupled, we can determine the age-metallicity-relation (AMR) for our present sample of red giants (500 stars). The measured AMR enables us to derive the metallicity distribution of all field stars in our selected regions after taking various selection effects into account. Since the metallicity distribution of the stellar component of a galaxy yields information on the (chemical) evolution that is independent of the details of the star formation history, we can constrain chemical enrichment scenarios for the LMC based on this data. The observed distribution is not compatible with a simple box or a leaky box model, since too few metal-poor stars have been found (this is analogous to the Galactic G-dwarf problem). This statement holds for all our observed fields. Our data favour a scenario of the LMC evolution, in which an infall of non-enriched or metal-poor gas is needed to explain the scarcity of metal-poor field stars compared to more metal-rich ones.

  13. Chemical Homogeneity in the Hyades

    E-print Network

    G. M. De Silva; C. Sneden; D. B. Paulson; M. Asplund; J. Bland-Hawthorn; M. S. Bessell; K. C. Freeman

    2005-09-09

    We present an abundance analysis of the heavy elements Zr, Ba, La, Ce, and Nd for Hyades cluster F-K dwarfs based on high resolution, high S/N ratio spectra from Keck/HIRES. The derived abundances show the stellar members to be highly uniform, although some elements show a small residual trend with temperature. The rms scatter for each element for the cluster members is as follows; Zr = 0.055 dex, Ba = 0.049 dex, Ce = 0.025 dex, La = 0.025 dex, Nd = 0.032 dex. This is consistent with the measurement errors, and implies that there is little or no intrinsic scatter among the Hyades members. Several stars thought to be non-members of the cluster based on their kinematics are found to deviate from the cluster mean abundances by about 2sigma. Establishing chemical homogeneity in open clusters is the primary requirement for the viability of chemically tagging Galactic disk stars to common formation sites, in order to unravel the dissipative history of early disk formation.

  14. Eudesmane derivatives from Tessaria integrifolia.

    PubMed

    Ono, M; Masuoka, C; Odake, Y; Ito, Y; Nohara, T

    2000-02-01

    Five eudesmane-type sesquiterpenoids were isolated from the methanol extract of the aerial part of Tessaria integrifolia Ruiz. et Pavon (Compositae). Their structures were elucidated on the basis of spectroscopic analysis is well as chemical evidence. PMID:10731027

  15. Chemical Reference Literature.

    ERIC Educational Resources Information Center

    Young, Shirley M.

    An innovative and effective laboratory experiment of chemical reference literature is reported. The objectives of the experiment are to acquaint the first term student of college chemistry with the vast source of chemical literature that is available to him; to raise the general level of scientific literacy of these first term college students;…

  16. Chemical Reactions and Stoichiometry

    NSDL National Science Digital Library

    2012-07-31

    In this activity, students explore reactions in which chemical bonds are formed and broken. Students experiment with changing the temperature and the concentration of the atoms in order to see how these affect reaction rates. They also learn how to communicate what happens during a chemical reaction by writing the ratios of reactants and products, known as stoichiometry.

  17. Great Lakes: Chemical Monitoring

    ERIC Educational Resources Information Center

    Delfino, Joseph J.

    1976-01-01

    The Tenth Great Lakes Regional Meeting of the American Chemical Society met to assess current Chemical Research activity in the Great Lakes Basin, and addressed to the various aspects of the theme, Chemistry of the Great Lakes. Research areas reviewed included watershed studies, atmospheric and aquatic studies, and sediment studies. (BT)

  18. Chemicals and Allied Products.

    ERIC Educational Resources Information Center

    Nelson, R. F.; Hovious, J. C.

    1978-01-01

    Presents a literature review of wastes from chemical industry, covering publications of 1976-77. This review covers: (1) wastewater treatment by-product type; (2) biological, and physical/chemical treatments; and (3) source treatment. A list of 80 references is also presented. (HM)

  19. Chemical Engineering Andrew Zydney

    E-print Network

    Maranas, Costas

    discipline ·Undergraduate curriculum combines courses in sciences with a strong focus on mathematics Engineers focus on the processes involved in making new products, including chemical reactions, but they still find a way to have fun #12;Chemical Engineering at the Center Physics Mathematics Biology

  20. Chemistry and Chemical Biology

    E-print Network

    Linhardt, Robert J.

    Chemistry and Chemical Biology AT RENSSELAER ONE WORD To Drive Discovery -- RENSSELAER What is the best Chemistry Ph.D. program for you? Choosing the right Ph.D. Chemistry program depends on many interests, we encourage you consider the Department of Chemistry and Chemical Biology at Rensselaer. WHY

  1. Elemental Chemical Puzzlers

    ERIC Educational Resources Information Center

    Thomas, Nicholas C.

    2009-01-01

    This paper provides nine short chemically based puzzles or problems extensible for use with students from middle school to college. Some of these will strengthen students' recognition of individual elements and element names. Others require students to focus on the salient properties of given chemical elements.

  2. Chemical cloud tracking systems

    NASA Astrophysics Data System (ADS)

    Grim, Larry B.; Gruber, Thomas C., Jr.; Marshall, Martin; Rowland, Brad

    2002-02-01

    This paper describes the Chemical Cloud Tracking System (CCTS) which has been installed at Dugway Proving Ground. The CCTS allows mapping of chemical clouds in real time from a safe standoff distance. The instruments used are passive standoff chemical agent detectors (FTIRs). Each instrument individually can only measure the total of all the chemical in its line-of-site; the distance to the cloud is unknown. By merging data from multiple vantage points (either one instrument moving past the cloud or two or more instruments spaced so as to view the cloud from different directions) a map of the cloud locations can be generated using tomography. To improve the sensitivity and accuracy of the cloud map, chemical point sensors can be added to the sensor array being used. The equipment required for the CCTS is commercially available. Also, the data fusion techniques (tomography) have been demonstrated previously in the medical field. The Chemical Cloud Tracking System can monitor the movement of many chemical clouds of either military or industrial origin. Since the technique is standoff, the personnel are not exposed to toxic hazards while they follow the cloud. Also, the equipment works on-the-move which allows rapid response to emergency situations (plant explosions, tanker car accidents, chemical terrorism, etc.).

  3. Safety Issues Chemical Storage

    E-print Network

    Cohen, Robert E.

    of fume hoods. Minimize chemical storage in fume hoods. · Do not store flammable, volatile toxic in fume hood. Reactives stored with incompatible chemicals. Liquids stored with solids for separate groups. Note: Most fume hoods have a flammable cabinet and a vented corrosive cabinet under them

  4. Department of Chemical Engineering

    E-print Network

    Acton, Scott

    Developing Leaders of Innovation Department of Chemical Engineering #12;At the University of Virginia, we educate students in traditional and nontraditional areas of chemical engineering, giving them. Master of Engineering and Master of Science degrees are offered, with the Master of Engineering student

  5. Chemically Consistent Evolutionary Synthesis

    E-print Network

    Uta Fritze-v. Alvensleben; Peter Weilbacher; Jens Bicker

    2002-10-24

    To account for the range of stellar metallicities in local galaxies and for the increasing importance of low metallicities at higher redshift we present chemically consistent models for the spectral and chemical evolution of galaxies over cosmological timescales. We discuss advantages, limitations and future prospects of our approach.

  6. Misconceptions of chemical equilibrium

    Microsoft Academic Search

    Mark W. Hackling; Patrick J. Garnett

    1985-01-01

    Those propositions deemed necessary for an understanding of chemical equilibrium and Le Chatelier's Principle were defined by the investigators and validated.Thirty, Year 12 Western Australian chemistry students (17 years of age) who had studied chemical equilibrium were interviewed and students’ responses were coded into various categories of misconception that had been identified. The most significant misconceptions revealed by the study

  7. Difficult Decisions: Chemical Warfare.

    ERIC Educational Resources Information Center

    Slesnick, Irwin L.; Miller, John A.

    1988-01-01

    Gives the background history and chemistry of modern day chemical warfare from World War I to the present. Provides discussion questions to stimulate deeper thinking on the issue. Contains a discussion activity called "Can New Chemical Weapons Lead to Humane Warfare?" (CW)

  8. CHEMICAL PROCESSES IN SOILS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Chemical Processes in Soils” edited by Tabatabai and D.L. Sparks (2005) is a key review useful for soil scientists, agronomists, conservationists, environmental scientists and other related professionals who need to understand these processes of chemical reactions and how they may be related to the...

  9. Recognizing Chemical Hazards Module

    NSDL National Science Digital Library

    The Center for the Advancement of Process Technology presents this free sample module on recognizing chemical hazards. It focuses on chemical hazards specific to process industries, and their impact on safety, health and the environment. The material also introduces the purpose and components of an MSDS.

  10. Chemical and Physical Changes

    NSDL National Science Digital Library

    The phenomenon is a chemical reaction between sugar and sulfuric acid. The demonstration (a discrepant event) compares the way sugar and water interact when combined (physical change) to the way sugar and sulfuric acid interact when combined (chemical change). In part II, students are given additional substances and changes to observe.

  11. Chemical warfare agents

    Microsoft Academic Search

    Rohit Shenoi

    2002-01-01

    There is an increased risk that civilian populations will be targets of domestic terrorism. Release of chemical warfare agents in these populations can cause a large number of casualties, with children being disproportionately affected. Chemical agents pose a significant risk to unprepared medical providers. Emergency medical personnel must be able to diagnose and manage victims of toxic exposures. This article

  12. Chemical Changes: Burning”

    NSDL National Science Digital Library

    Kris Ryan

    2012-07-25

    This lesson demonstrates how students can apply the process of identifying main idea and supporting details to show the different ways burning can chemically change matter. The students can identify these changes and discuss the details that support these changes, which will help them further understand how burning matter is considered a chemical change.

  13. Chemical Kinetic Models for HCCI and Diesel Combustion

    SciTech Connect

    Pitz, W J; Westbook, C K; Mehl, M

    2008-10-30

    Hydrocarbon fuels for advanced combustion engines consist of complex mixtures of hundreds or even thousands of different components. These components can be grouped into a number of chemically distinct classes, consisting of n-paraffins, branched paraffins, cyclic paraffins, olefins, oxygenates, and aromatics. Biodiesel contains its own unique chemical class called methyl esters. The fractional amounts of these chemical classes are quite different in gasoline, diesel fuel, oil-sand derived fuels and bio-derived fuels, which contributes to the very different combustion characteristics of each of these types of combustion systems. The objectives of this project are: (1) Develop detailed chemical kinetic models for fuel components used in surrogate fuels for diesel and HCCI engines; (2) Develop surrogate fuel models to represent real fuels and model low temperature combustion strategies in HCCI and diesel engines that lead to low emissions and high efficiency; and (3) Characterize the role of fuel composition on low temperature combustion modes of advanced combustion engines.

  14. PhD Chemical Engineering MS Chemical Engineering

    E-print Network

    Collins, Gary S.

    1 PhD Chemical Engineering MS Chemical Engineering Bylaws Gene and Linda Voiland School of Chemical Engineering and Bioengineering College of Engineering and Architecture Approved by Voiland School facultyD Chemical Engineering, MS Chemical Engineering B. Discipline: Edgar, et al.1 provide a succinct description

  15. Quality of poultry litter-derived granular activated carbon

    Microsoft Academic Search

    Guannan Qiu; Mingxin Guo

    2010-01-01

    Utilization of poultry litter as a source material for generating activated carbon is a value-added and environmentally beneficial approach to recycling organic waste. In this study, the overall quality of poultry litter-derived granular activated carbon was systematically evaluated based on its various physical and chemical properties. Granular activated carbon generated from pelletized poultry litter following a typical steam-activation procedure possessed

  16. Soap-based detergent formulations: XIV. Amphoteric derivatives of alkylbenzenesulfonamides

    Microsoft Academic Search

    R. G. Bistline; W. R. Noble; W. M. Linfield

    1976-01-01

    Surface active amphoteric derivatives were prepared from alkylbenzenesulfonyl chlorides. Industrial detergent alkylates, as\\u000a well as benzene and pure 1-phenylalkanes whose side chains ranged from C1 to C12, were used as starting materials in this study of chemical structure-physical property relationships. The alkylbenzenes were\\u000a first converted into the corresponding alkylbenzenesulfonyl chlorides with chlorosulfonic acid, and the sulfonyl chlorides\\u000a were further treated

  17. Preclinical safety testing of biotechnology-derived pharmaceuticals

    Microsoft Academic Search

    Frank R. Brennan; Leigh Shaw; Mark G. Wing; Christine Robinson

    2004-01-01

    The unique and complex nature of biotechnology-derived pharmaceuticals has meant that it is often not possible to follow the\\u000a conventional safety testing programs used for chemicals, and hence they are evaluated on a case-by-case basis. Nonclinical\\u000a safety testing programs must be rationally designed with a strong scientific understanding of the product, including its method\\u000a of manufacture, purity, sequence, structure, species

  18. Amaryllidaceae Isocarbostyril Alkaloids and Their Derivatives as Promising Antitumor Agents

    PubMed Central

    Ingrassia, Laurent; Lefranc, Florence; Mathieu, Véronique; Darro, Francis; Kiss, Robert

    2008-01-01

    This review covers the isolation, total synthesis, biologic activity, and more particularly the in vitro and in vivo antitumor activities of naturally occurring isocarbostyril alkaloids from the Amaryllidaceae family. Starting from these natural products, new derivatives have been synthesized to explore structure-activity relationships within the chemical class and to obtain potential candidates for preclinical development. This approach appears to be capable of providing novel promising anticancer agents. PMID:18607503

  19. Chemical recognition software

    SciTech Connect

    Wagner, J.S.; Trahan, M.W.; Nelson, W.E.; Hargis, P.H. Jr.; Tisone, G.C.

    1994-06-01

    We have developed a capability to make real time concentration measurements of individual chemicals in a complex mixture using a multispectral laser remote sensing system. Our chemical recognition and analysis software consists of three parts: (1) a rigorous multivariate analysis package for quantitative concentration and uncertainty estimates, (2) a genetic optimizer which customizes and tailors the multivariate algorithm for a particular application, and (3) an intelligent neural net chemical filter which pre-selects from the chemical database to find the appropriate candidate chemicals for quantitative analyses by the multivariate algorithms, as well as providing a quick-look concentration estimate and consistency check. Detailed simulations using both laboratory fluorescence data and computer synthesized spectra indicate that our software can make accurate concentration estimates from complex multicomponent mixtures, even when the mixture is noisy and contaminated with unknowns.

  20. Chemical recognition software

    SciTech Connect

    Wagner, J.S.; Trahan, M.W.; Nelson, W.E.; Hargis, P.J. Jr.; Tisone, G.C.

    1994-12-01

    We have developed a capability to make real time concentration measurements of individual chemicals in a complex mixture using a multispectral laser remote sensing system. Our chemical recognition and analysis software consists of three parts: (1) a rigorous multivariate analysis package for quantitative concentration and uncertainty estimates, (2) a genetic optimizer which customizes and tailors the multivariate algorithm for a particular application, and (3) an intelligent neural net chemical filter which pre-selects from the chemical database to find the appropriate candidate chemicals for quantitative analyses by the multivariate algorithms, as well as providing a quick-look concentration estimate and consistency check. Detailed simulations using both laboratory fluorescence data and computer synthesized spectra indicate that our software can make accurate concentration estimates from complex multicomponent mixtures. even when the mixture is noisy and contaminated with unknowns.

  1. Chemical evolutionary games

    PubMed Central

    Aristotelous, Andreas C.; Durrett, Richard

    2014-01-01

    Inspired by the use of hybrid cellular automata in modeling cancer, we introduce a generalization of evolutionary games in which cells produce and absorb chemicals, and the chemical concentrations dictate the death rates of cells and their fitnesses. Our long term aim is to understand how the details of the interactions in a system with n species and m chemicals translate into the qualitative behavior of the system. Here, we study two simple 2 × 2 games with two chemicals and revisit the two and three species versions of the one chemical colicin system studied earlier by Durrett and Levin [28]. We find that in the 2 × 2 examples, the behavior of our new spatial model can be predicted from that of the mean field differential equation using ideas of [12]. However, in the three species colicin model, the system with diffusion does not have the coexistence which occurs in the lattices model in which sites interact with only their nearest neighbors. PMID:24513098

  2. Tortuous path chemical preconcentrator

    DOEpatents

    Manginell, Ronald P. (Albuquerque, NM); Lewis, Patrick R. (Albuquerque, NM); Adkins, Douglas R. (Albuquerque, NM); Wheeler, David R. (Albuquerque, NM); Simonson, Robert J. (Cedar Crest, NM)

    2010-09-21

    A non-planar, tortuous path chemical preconcentrator has a high internal surface area having a heatable sorptive coating that can be used to selectively collect and concentrate one or more chemical species of interest from a fluid stream that can be rapidly released as a concentrated plug into an analytical or microanalytical chain for separation and detection. The non-planar chemical preconcentrator comprises a sorptive support structure having a tortuous flow path. The tortuosity provides repeated twists, turns, and bends to the flow, thereby increasing the interfacial contact between sample fluid stream and the sorptive material. The tortuous path also provides more opportunities for desorption and readsorption of volatile species. Further, the thermal efficiency of the tortuous path chemical preconcentrator is comparable or superior to the prior non-planar chemical preconcentrator. Finally, the tortuosity can be varied in different directions to optimize flow rates during the adsorption and desorption phases of operation of the preconcentrator.

  3. New derivative of carnosine for nanoparticle assemblies.

    PubMed

    Bellia, Francesco; Oliveri, Valentina; Rizzarelli, Enrico; Vecchio, Graziella

    2013-01-01

    Carnosine (?-alanyl-l-histidine) is an endogenous dipeptide, extensively studied owing to its multifunctional activity exhibited in tissues of several animal species. This natural compound may act as a physiological buffer, ion-chelating agent (especially for copper(II) and zinc(II)), antioxidant and antiglycating agent. The main limit for the therapeutical uses of carnosine is the rapid hydrolysis mostly in human plasma by carnosinase. The chemical derivatization of carnosine is a promising strategy to improve the bioavailability of the dipeptide and facilitating the site-specific transport to different tissues. On this basis, a new carnosine derivative with biotin was synthesized and structurally characterized by NMR and MS measurements, with aim of exploiting the avidin-biotin technology that offers a universal system for selective delivery of any biotinylated agent. The stability of the new carnosine derivative towards the hydrolytic action of serum carnosinase as well as the copper(II) binding ability of the carnosine-biotin conjugate were also assessed. The binding affinity of the new molecular entity to avidin and streptavidin, investigated by a spectrophotometric assay, was exploited to functionalize avidin- and streptavidin-gold nanoparticles with the carnosine-biotin conjugate. PMID:24158014

  4. Quinolines derivatives as novel sunscreening agents.

    PubMed

    Polonini, Hudson C; Dias, Rafael M P; Souza, Isabela O; Gonçalves, Karla Mara; Gomes, Tiago B B; Raposo, Nádia R B; da Silva, Adilson David

    2013-08-15

    Currently, the research and development of sunscreens play an important role on the synthesis of actives that are stable in various kinds of formulations-in addition to their efficiency and broad spectrum of protection against ultraviolet radiation. Our objective here was to synthesize new sunscreening chemical agents using quinoline as a base molecule. Twelve quinoline derivatives were synthesized, four of them novel molecules, and their photoprotective activity was determined in vitro using diffuse transmittance spectrophotometry. We determined their SPF, UVAPF, UVA/UVB ratio, critical wavelength and Boots Star Rating. The quinolines derivatives presented a varied profile of photoprotection, their SPF ranging from 2 to 11 and their UVAPF from 2 to 7. In terms of the critical wavelength, all molecules were considered of broad-spectrum by different classifications. Regarding the Boots Star Rating, one compound received no rating, seven of them received a three stars rating, three received a four stars rating and three were given a five stars rating. The molecules showed in the present work have a wide range of possibilities for creating new sunscreen products, once they have good SPF or UVAPF for single molecules, and they also possess other different qualities that can act synergistically. PMID:23856048

  5. Cytochalasin derivatives from a jellyfish-derived fungus Phoma sp.

    PubMed

    Kim, Eun La; Wang, Haibo; Park, Ju Hee; Hong, Jongki; Choi, Jae Sue; Im, Dong Soon; Chung, Hae Young; Jung, Jee H

    2015-05-15

    Four new cytochalasin derivatives (1-4), together with proxiphomin (5), were isolated from a jellyfish-derived fungus Phoma sp. The planar structures and relative stereochemistry were established by analysis of 1D and 2D NMR data. The absolute configuration was defined by the modified Mosher's method. The compounds showed moderate cytotoxicity against a small panel of human solid tumor cell lines (A549, KB, and HCT116). PMID:25881821

  6. Crystallographic investigations of biotin and carboxybiotin derivatives.

    PubMed

    Stallings, W; Detitta, G T

    1985-01-01

    The structures of a family of biotin and carboxybiotin derivatives have provided information on the mechanism of biotin action. The ureido moiety of the uncarboxylated cofactor is polarized and able to interact with ions and polar molecules; intermolecular interactions in the biotin derivatives suggest biochemical mechanisms resulting in nucleophilic activation to the enol tautomer. N1' carboxylation of biotin is important not only as a chemical reaction to generate the carboxyl-transferring species, carboxybiotin, but also in acting as a switch to depolarize the ureido carbonyl oxygen, and thereby facilitating interactions with non-polar molecules. The structure of an N1' methoxycarbonyl biotin derivative reveals such an interaction between the carbonyl oxygen, O2', and a neighboring methyl group. A computer-generated space-filing model of the van der Waals contacts involved in this interaction reveals that the methyl group is locked with respect to rotation and thus suggests a structural basis for the stereospecificity observed in the carboxyl-transferring half-reaction. The flexibility of the valeryl side chains in this family of structures provides translocation models in line with magnetic resonance data which indicate that the translocation events involve motions of, at most, 7 A. Our models demonstrate that such motions may be accomplished by simple, observed conformational changes in bonds of the valeryl side chain which locally adjoin the bicyclic ring system. High resolution, low temperature diffraction data will allow visualization of the bonding and lone pair electrons in biotin. These studies will serve to extend and fine-tune our description of the electronic structure of biotin which is currently based on accurate measurements of bond distances and angles. PMID:3860171

  7. Chemical Vapor Deposition of Silicon from Silane Pyrolysis

    NASA Technical Reports Server (NTRS)

    Praturi, A. K.; Lutwack, R.; Hsu, G.

    1977-01-01

    The four basic elements in the chemical vapor deposition (CVD) of silicon from silane are analytically treated from a kinetic standpoint. These elements are mass transport of silane, pyrolysis of silane, nucleation of silicon, and silicon crystal growth. Rate expressions that describe the various steps involved in the chemical vapor deposition of silicon were derived from elementary principles. Applications of the rate expressions for modeling and simulation of the silicon CVD are discussed.

  8. Real-time propagators at finite temperature and chemical potential

    E-print Network

    S. Mallik; Sourav Sarkar

    2009-01-08

    We derive a form of spectral representations for all bosonic and fermionic propagators in the real-time formulation of field theory at finite temperature and chemical potential. Besides being simple and symmetrical between the bosonic and the fermionic types, these representations depend explicitly on analytic functions only. This last property allows a simple evaluation of loop integrals in the energy variables over propagators in this form, even in presence of chemical potentials, which is not possible over their conventional form.

  9. Chemical Potential Jump during Evaporation of a Quantum Bose Gas

    E-print Network

    E. A. Bedrikova; A. V. Latyshev

    2013-01-07

    The dependence of the chemical potential jump coefficient on the evaporation coefficient is analyzed for the case in which the evaporating component is a Bose gas. The concentration of the evaporating component is assumed to be much lower than the concentration of the carrier gas. The expression for the chemical potential jump is derived from the analytic solution of the problem for the case in which the collision frequency of molecules of the evaporating component is constant.

  10. Chemical composition and origin of the earth's primitive mantle

    Microsoft Academic Search

    S.-S. Sun

    1982-01-01

    The chemical composition of the earth's primitive crust is estimated by critical evaluation of data derived from ultramafic mantle samples and partial melting model calculations for mafic and ultramafic magmas of various ages. Chemical irregularities inferred in the earth are discussed in terms of earth-forming and mantle-core differentiation processes. The well-defined continuous depletion trend of lithophile elements towards lower temperature

  11. The Open Cluster Chemical Abundances from Spanish Observatories survey (OCCASO)

    NASA Astrophysics Data System (ADS)

    Carrera, R.; Casamiquela, L.; Balaguer-Núñez, L.; Jordi, C.; Pancino, E.; Allende-Prieto, C.; Blanco-Cuaresma, S.; Martínez-Vázquez, C. E.; Murabito, S.; del Pino, A.; Aparicio, A.; Gallart, C.; Recio-Blanco, A.

    2015-05-01

    We present the motivation, design and current status of the Open Cluster Chemical Abundances from Spanish Observatories survey (OCCASO). Using the high resolution spectroscopic facilities available at Spanish observatories, OCCASO will derive chemical abundances in a sample of 20 to 25 OCs older than 0.5 Gyr. This sample will be used to study in detail de formation and evolution of the Galactic disc using OCs as tracers.

  12. Phylogenetic examination of crude drugs derived from Yunnanese Swertia plants.

    PubMed

    Kakiuchi, Nobuko; Iwaki, Naoko; Mikage, Masayuki; Xiao, Huai; Wang, Zhigang; Hattori, Masao

    2014-01-01

    Aiming to examine whether the genetic background of the crude drugs derived from four Yunnanese Swertia plants and their chemical constituent profiles correlate, we analyzed the nucleotide sequences of their nuclear ribosomal DNA regions including ITS1, 5.8S ribosomal RNA gene, and ITS2, together with those of Japanese S. japonica and S. pseudochinensis from Hebei Province. The result that two of the Yunnanese Swertia plants, S. binchuanensis and S. punicea, were genetically similar may explain their similarity in chemical constituent profiles. On the other hand, in spite of differences in chemical profile, S. decora and S. pseudochinensis were genetically close. The other Yunnanese Swertia plants, S. delavayi, and S. japonica, stood at intermediate positions between these two genetically similar pairs. The result suggests that although genetic background would have an influence, environmental factors, e.g., soil and weather conditions, might be critical for their production of secondary metabolites. PMID:23653334

  13. Quinazoline derivatives: synthesis and bioactivities

    PubMed Central

    2013-01-01

    Owing to the significant biological activities, quinazoline derivatives have drawn more and more attention in the synthesis and bioactivities research. This review summarizes the recent advances in the synthesis and biological activities investigations of quinazoline derivatives. According to the main method the authors adopted in their research design, those synthetic methods were divided into five main classifications, including Aza-reaction, Microwave-assisted reaction, Metal-mediated reaction, Ultrasound-promoted reaction and Phase-transfer catalysis reaction. The biological activities of the synthesized quinazoline derivatives also are discussed. PMID:23731671

  14. Complex higher order derivative theories

    SciTech Connect

    Margalli, Carlos A.; Vergara, J. David [Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, Apartado Postal 70-543, Mexico 04510 DF (Mexico)

    2012-08-24

    In this work is considered a complex scalar field theory with higher order derivative terms and interactions. A procedure is developed to quantize consistently this system avoiding the presence of negative norm states. In order to achieve this goal the original real scalar high order field theory is extended to a complex space attaching a complex total derivative to the theory. Next, by imposing reality conditions the complex theory is mapped to a pair of interacting real scalar field theories without the presence of higher derivative terms.

  15. or ChemiCal engineering?

    E-print Network

    Wagner, Stephan

    and the chemical engineer work so closely in industry, there is little doubt that the chemical engineer who has industries. In recent years chemical engineers have started working in biotechnology, designing bioreactorsChemistry or ChemiCal engineering? Do both at Wits! www.wits.ac.za #12;Chemistry or ChemiCal

  16. Wyss Institute Chemical Hygiene Plan CHEMICAL HYGIENE PLAN

    E-print Network

    Napp, Nils

    ................................................................................................... 18 3.10 VENTILATION, FUME HOODS, AND PROPER OPERATIONSWyss Institute Chemical Hygiene Plan CHEMICAL HYGIENE PLAN The Wyss Institute for Biologically Inspired Engineering June 2014 #12;Wyss Institute Chemical Hygiene Plan TABLE OF CONTENTS 1.0 POLICY

  17. The U.S. Chemical Industry, Foreign Chemical Industries

    ERIC Educational Resources Information Center

    Chemical and Engineering News, 1972

    1972-01-01

    This section of the annual report on the chemical industry provides data on the chemical production of Japan, West Germany, United Kingdom, Italy, and France, including the output of major chemical products in these nations. (PR)

  18. Chemical and Biochemical Engineering Getting Computing Help at Chemical and

    E-print Network

    Chemical and Biochemical Engineering Getting Computing Help at Chemical and Biochemical Engineering Help for Departmental Systems. Users of computing systems at Chemical and Biochemical Engineering can get technical support for most issues by contacting the Systems Administrator at help

  19. Cognitive effects of cell-derived and synthetically-derived A? oligomers

    PubMed Central

    Reed, Miranda N.; Hofmeister, Jacki J.; Jungbauer, Lisa; Welzel, Alfred T.; Yu, Chunjiang; Sherman, Mathew A.; Lesné, Sylvain; LaDu, Mary Jo; Walsh, Dominic M.; Ashe, Karen H.; Cleary, James P.

    2010-01-01

    Soluble forms of amyloid-? peptide (A?) are a molecular focus in Alzheimer's disease research. Soluble A? dimers (? 8 kDa), timers (? 12 kDa), tetramers (? 16 kDa) and A?*56 (? 56 kDa) have shown biological activity. These A? molecules have been derived from diverse sources, including chemical synthesis, transfected cells, and mouse and human brain, leading to uncertainty about toxicity and potency. Herein, synthetic A? peptide-derived oligomers, cell- and brain-derived low-n oligomers, and A?*56, were injected intracerebroventricularly (icv) into rats assayed under the Alternating Lever Cyclic Ratio (ALCR) cognitive assay. Cognitive deficits were detected at 1.3?M of synthetic A? oligomers and at low nanomolar concentrations of cell-secreted A? oligomers. Trimers, from transgenic mouse brain (Tg2576), did not cause cognitive impairment at any dose tested, whereas A?*56 induced concentration-dependent cognitive impairment at 0.9?M and 1.3?M. Thus, while multiple forms of A? have cognition impairing activity, there are significant differences in effective concentration and potency. PMID:20031278

  20. Chemical process hazards analysis

    SciTech Connect

    NONE

    1996-02-01

    The Office of Worker Health and Safety (EH-5) under the Assistant Secretary for the Environment, Safety and Health of the US Department (DOE) has published two handbooks for use by DOE contractors managing facilities and processes covered by the Occupational Safety and Health Administration (OSHA) Rule for Process Safety Management of Highly Hazardous Chemicals (29 CFR 1910.119), herein referred to as the PSM Rule. The PSM Rule contains an integrated set of chemical process safety management elements designed to prevent chemical releases that can lead to catastrophic fires, explosions, or toxic exposures. The purpose of the two handbooks, ``Process Safety Management for Highly Hazardous Chemicals`` and ``Chemical Process Hazards Analysis,`` is to facilitate implementation of the provisions of the PSM Rule within the DOE. The purpose of this handbook ``Chemical Process Hazards Analysis,`` is to facilitate, within the DOE, the performance of chemical process hazards analyses (PrHAs) as required under the PSM Rule. It provides basic information for the performance of PrHAs, and should not be considered a complete resource on PrHA methods. Likewise, to determine if a facility is covered by the PSM rule, the reader should refer to the handbook, ``Process Safety Management for Highly Hazardous Chemicals`` (DOE- HDBK-1101-96). Promulgation of the PSM Rule has heightened the awareness of chemical safety management issues within the DOE. This handbook is intended for use by DOE facilities and processes covered by the PSM rule to facilitate contractor implementation of the PrHA element of the PSM Rule. However, contractors whose facilities and processes not covered by the PSM Rule may also use this handbook as a basis for conducting process hazards analyses as part of their good management practices. This handbook explains the minimum requirements for PrHAs outlined in the PSM Rule. Nowhere have requirements been added beyond what is specifically required by the rule.