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Sample records for biguanide derivatives chemical

  1. Copper-catalyzed arylation of biguanide derivatives via C-N cross-coupling reactions.

    PubMed

    Zhang, Chen; Huang, Bo; Bao, Ai-Qing; Li, Xiao; Guo, Shunna; Zhang, Jin-Quan; Xu, Jun-Zhi; Zhang, Rihao; Cui, Dong-Mei

    2015-12-21

    An efficient copper-catalyzed cross-coupling reaction of biguanide hydrochloride derivatives with both aryl iodides and bromides under mild conditions has been developed. The reaction occurred in good yields and tolerated aryl halides containing functionalities such as nitriles, sulfonamides, ethers, and halogens. Alkyl and cyclic substituted biguanidines were also well tolerated. PMID:26444146

  2. Optimization of biguanide derivatives as selective antitumor agents blocking adaptive stress responses in the tumor microenvironment

    PubMed Central

    Narise, Kosuke; Okuda, Kensuke; Enomoto, Yukihiro; Hirayama, Tasuku; Nagasawa, Hideko

    2014-01-01

    Adaptive cellular responses resulting from multiple microenvironmental stresses, such as hypoxia and nutrient deprivation, are potential novel drug targets for cancer treatment. Accordingly, we focused on developing anticancer agents targeting the tumor microenvironment (TME). In this study, to search for selective antitumor agents blocking adaptive responses in the TME, thirteen new compounds, designed and synthesized on the basis of the arylmethylbiguanide scaffold of phenformin, were used in structure activity relationship studies of inhibition of hypoxia inducible factor (HIF)-1 and unfolded protein response (UPR) activation and of selective cytotoxicity under glucose-deprived stress conditions, using HT29 cells. We conducted luciferase reporter assays using stable cell lines expressing either an HIF-1-responsive reporter gene or a glucose-regulated protein 78 promoter-reporter gene, which were induced by hypoxia and glucose deprivation stress, respectively, to screen for TME-targeting antitumor drugs. The guanidine analog (compound 2), obtained by bioisosteric replacement of the biguanide group, had activities comparable with those of phenformin (compound 1). Introduction of various substituents on the phenyl ring significantly affected the activities. In particular, the o-methylphenyl analog compound 7 and the o-chlorophenyl analog compound 12 showed considerably more potent inhibitory effects on HIF-1 and UPR activation than did phenformin, and excellent selective cytotoxicity under glucose deprivation. These compounds, therefore, represent an improvement over phenformin. They also suppressed HIF-1- and UPR-related protein expression and secretion of vascular endothelial growth factor-A. Moreover, these compounds exhibited significant antiangiogenic effects in the chick chorioallantoic membrane assay. Our structural development studies of biguanide derivatives provided promising candidates for a novel anticancer agent targeting the TME for selective cancer therapy, to be subjected to further in vivo study. PMID:24944508

  3. Biguanide related compounds in traditional antidiabetic functional foods.

    PubMed

    Perla, Venu; Jayanty, Sastry S

    2013-06-01

    Biguanides such as metformin are widely used worldwide for the treatment of type-2 diabetes. The identification of guanidine and related compounds in French lilac plant (Galega officinalis L.) led to the development of biguanides. Despite of their plant origin, biguanides have not been reported in plants. The objective of this study was to quantify biguanide related compounds (BRCs) in experimentally or clinically substantiated antidiabetic functional plant foods and potatoes. The corrected results of the Voges-Proskauer (V-P) assay suggest that the highest amounts of BRCs are present in green curry leaves (Murraya koenigii (L.) Sprengel) followed by fenugreek seeds (Trigonella foenum-graecum L.), green bitter gourd (Momordica charantia Descourt.), and potato (Solanum tuberosum L.). Whereas, garlic (Allium sativum L.), and sweet potato (Ipomea batatas (L.) Lam.) contain negligible amounts of BRCs. In addition, the possible biosynthetic routes of biguanide in these plant foods are discussed. PMID:23411283

  4. Selective inhibition of deactivated mitochondrial complex I by biguanides.

    PubMed

    Matsuzaki, Satoshi; Humphries, Kenneth M

    2015-03-24

    Biguanides are widely used antihyperglycemic agents for diabetes mellitus and prediabetes treatment. Complex I is the rate-limiting step of the mitochondrial electron transport chain (ETC), a major source of mitochondrial free radical production, and a known target of biguanides. Complex I has two reversible conformational states, active and de-active. The deactivated state is promoted in the absence of substrates but is rapidly and fully reversed to the active state in the presence of NADH. The objective of this study was to determine the relative sensitivity of active/de-active complex I to biguanide-mediated inhibition and resulting superoxide radical (O?(•?)) production. Using isolated rat heart mitochondria, we show that deactivation of complex I sensitizes it to metformin and phenformin (4- and 3-fold, respectively), but not to other known complex I inhibitors, such as rotenone. Mitochondrial O?(•?) production by deactivated complex I was measured fluorescently by NADH-dependent 2-hydroxyethidium formation at alkaline pH to impede reactivation. Superoxide production was 260.4% higher than in active complex I at pH 9.4. However, phenformin treatment of de-active complex I decreased O?(•?) production by 14.9%, while rotenone increased production by 42.9%. Mitochondria isolated from rat hearts subjected to cardiac ischemia, a condition known to induce complex I deactivation, were sensitized to phenformin-mediated complex I inhibition. This supports the idea that the effects of biguanides are likely to be influenced by the complex I state in vivo. These results demonstrate that the complex I active and de-active states are a determinant in biguanide-mediated inhibition. PMID:25719498

  5. Effects of metformin and other biguanides on oxidative phosphorylation in mitochondria

    PubMed Central

    Bridges, Hannah R.; Jones, Andrew J. Y.; Pollak, Michael N.; Hirst, Judy

    2014-01-01

    The biguanide metformin is widely prescribed for Type II diabetes and has anti-neoplastic activity in laboratory models. Despite evidence that inhibition of mitochondrial respiratory complex I by metformin is the primary cause of its cell-lineage-specific actions and therapeutic effects, the molecular interaction(s) between metformin and complex I remain uncharacterized. In the present paper, we describe the effects of five pharmacologically relevant biguanides on oxidative phosphorylation in mammalian mitochondria. We report that biguanides inhibit complex I by inhibiting ubiquinone reduction (but not competitively) and, independently, stimulate reactive oxygen species production by the complex I flavin. Biguanides also inhibit mitochondrial ATP synthase, and two of them inhibit only ATP hydrolysis, not synthesis. Thus we identify biguanides as a new class of complex I and ATP synthase inhibitor. By comparing biguanide effects on isolated complex I and cultured cells, we distinguish three anti-diabetic and potentially anti-neoplastic biguanides (metformin, buformin and phenformin) from two anti-malarial biguanides (cycloguanil and proguanil): the former are accumulated into mammalian mitochondria and affect oxidative phosphorylation, whereas the latter are excluded so act only on the parasite. Our mechanistic and pharmacokinetic insights are relevant to understanding and developing the role of biguanides in new and existing therapeutic applications, including cancer, diabetes and malaria. PMID:25017630

  6. Biguanide-, imine-, and guanidine-based networks as catalysts for transesterification of vegetable oil

    E-print Network

    Fasoli, Ezio

    Polycationic systems based on poly(hexamethylene biguanide) (PHMBG), branched polyethyleneimine (PEI) and poly(N-vinylguanidine) (PVG) have been evaluated as heterogeneous catalysts for the transesterification of sunflower ...

  7. Electron transport through chemically-derived nanostructures

    NASA Astrophysics Data System (ADS)

    Lim, Andrew Kean Leong

    Electrical devices that combine the functionality of lithographically patterned semiconductor circuits with the flexibility inherent in chemical systems present an opportunity to explore fundamental physical processes and simultaneously, to address more practical applications. This dissertation describes efforts to make such chemically-derived structures, by incorporating individual nanometre-sized molecules (C60 and semiconductor nanocrystals/nanorods) into a single electron transistor geometry. Electrical transport measurements are used to characterise these devices. A significant barrier to building these devices is the difficulty in connecting electrodes from the external metre-sized world where measurements are made to a nanometre-sized object. One solution is to place the molecule in a junction formed by the electromigration-induced failure of a metal nanowire, a technique that produces electrically stable transistors in surprisingly high yields. Understanding the process of junction formation is not only of intrinsic interest, but it has also proven to be a highly reliable diagnostic tool to differentiate between successful devices and tunnel junctions not containing the sample molecule. The fabrication of C60-based single electron transistors was one of the first applications of this method. Extensive transport spectroscopy was performed on these devices by tuning parameters such as the transistor bias voltage, the applied electric and magnetic fields and the temperature. The electronic and vibrational degrees of freedom of the cluster appear to couple during electron transport and a model for this behaviour was proposed, based on molecular oscillations within a transistor junction. On several occasions, individual C60 molecules were well connected to the junction electrodes, permitting observation of the Kondo effect in these devices. The break-junction technique was also used to create single electron transistors based upon colloidal semiconductor nanocrystals, facilitating spectroscopy on a semiconductor material that is quantum confined in three dimensions. The techniques to produce these nanocrystals are chemically quite flexible and recent syntheses have produced elongated nanorods where confinement is lost in one direction (resulting in a one-dimensional quantum wire). Preliminary experiments on these objects exhibit an intriguing dependence on the applied magnetic field.

  8. 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.

  9. In Vitro and In Vivo Modulation of Alternative Splicing by the Biguanide Metformin.

    PubMed

    Laustriat, Delphine; Gide, Jacqueline; Barrault, Laetitia; Chautard, Emilie; Benoit, Clara; Auboeuf, Didier; Boland, Anne; Battail, Christophe; Artiguenave, François; Deleuze, Jean-François; Bénit, Paule; Rustin, Pierre; Franc, Sylvia; Charpentier, Guillaume; Furling, Denis; Bassez, Guillaume; Nissan, Xavier; Martinat, Cécile; Peschanski, Marc; Baghdoyan, Sandrine

    2015-01-01

    Major physiological changes are governed by alternative splicing of RNA, and its misregulation may lead to specific diseases. With the use of a genome-wide approach, we show here that this splicing step can be modified by medication and demonstrate the effects of the biguanide metformin, on alternative splicing. The mechanism of action involves AMPK activation and downregulation of the RBM3 RNA-binding protein. The effects of metformin treatment were tested on myotonic dystrophy type I (DM1), a multisystemic disease considered to be a spliceopathy. We show that this drug promotes a corrective effect on several splicing defects associated with DM1 in derivatives of human embryonic stem cells carrying the causal mutation of DM1 as well as in primary myoblasts derived from patients. The biological effects of metformin were shown to be compatible with typical therapeutic dosages in a clinical investigation involving diabetic patients. The drug appears to act as a modifier of alternative splicing of a subset of genes and may therefore have novel therapeutic potential for many more diseases besides those directly linked to defective alternative splicing. PMID:26528939

  10. Fucoxanthin Derivatives: Synthesis and their Chemical Properties.

    PubMed

    Komba, Shiro; Kotake-Nara, Eiichi; Machida, Sachiko

    2015-01-01

    Novel fucoxanthin derivatives that could change the size of mixed micelles were synthesized. The mixed micelles under consideration consist of a bile acid and some additives. To change the affinity against a bile acid, we designed the synthesis of a fucoxanthin-lithocholic acid complex. Lithocholic acid is one of the bile acids. The 3-OH on lithocholic acid was protected by a levulinyl group, and the protected lithocholic acid was selectively coupled via an ester linkage to the 3-OH on fucoxanthin to obtain levulinyl-protected lithocholyl fucoxanthin (LevLF). The levulinyl group was then selectively deprotected using hydrazine to obtain a lithocholyl fucoxanthin (LF). The average sizes of the micelles that contained these compounds (fucoxanthin, LevLF, and LF) with a bile acid (sodium taurocholate) were measured. The LevLF induced larger micelles than fucoxanthin or LF. Interestingly, the addition of 1-oleoyl-rac-glycerol induced a more efficient change in the micelle size. The large micelles grew larger, and the small micelles became smaller. Triple-mixed micelles with LevLF, sodium taurocholate, and 1-oleoyl-rac-glycerol formed the largest micelle with a diameter of 68 nm. On the other hand, triple-mixed micelles using LF, sodium taurocholate, and 1-oleoyl-rac-glycerol made the smallest micelles with diameters as low as 12 nm. We also investigated the hydrolysis of these compounds with enzymes (esterase from porcine liver, lipase from porcine pancreas, and cholesterol esterase from Pseudomonas sp.). The ester linkage between the lithocholic acid and fucoxanthin of LevLF was hydrolyzed with cholesterol esterase. In addition, the intestinal absorption was examined with Caco-2 cells, and no advantageous change in absorption efficiency was observed by chemically modifying the fucoxanthin unless different micelles sizes and increasing hydrophobicity are induced. PMID:26250423

  11. Study of Epigenetic Properties of Poly(HexaMethylene Biguanide) Hydrochloride (PHMB)

    PubMed Central

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

    2014-01-01

    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 ?g/mL up to 20 ?g/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 ?g/mL after treatment with PHMB for 3 h, whereas the MTT test led to IC50 values of 80 ?g/mL, 160 ?g/mL and 160 ?g/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 ?g/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

  12. Energy metabolism determines the sensitivity of human hepatocellular carcinoma cells to mitochondrial inhibitors and biguanide drugs.

    PubMed

    Hsu, Chia-Chi; Wu, Ling-Chia; Hsia, Cheng-Yuan; Yin, Pen-Hui; Chi, Chin-Wen; Yeh, Tien-Shun; Lee, Hsin-Chen

    2015-09-01

    Human hepatocellular carcinoma (HCC) is one of the most common malignancies worldwide particularly in Asia. Deregulation of cellular energetics was recently included as one of the cancer hallmarks. Compounds that target the mitochondria in cancer cells were proposed to have therapeutic potential. Biguanide drugs which inhibit mitochondrial complex I and repress mTOR signaling are clinically used to treat type 2 diabetes mellitus patients (T2DM) and were recently found to reduce the risk of HCC in T2DM patients. However, whether alteration of energy metabolism is involved in regulating the sensitivity of HCC to biguanide drugs is still unclear. In the present study, we treated four HCC cell lines with mitochondrial inhibitors (rotenone and oligomycin) and biguanide drugs (metformin and phenformin), and found that the HCC cells which had a higher mitochondrial respiration rate were more sensitive to these treatments; whereas the HCC cells which exhibited higher glycolysis were more resistant. When glucose was replaced by galactose in the medium, the altered energy metabolism from glycolysis to mitochondrial respiration in the HCC cells enhanced the cellular sensitivity to mitochondrial inhibitors and biguanides. The energy metabolism change enhanced AMP-activated protein kinase (AMPK) activation, mTOR repression and downregulation of cyclin D1 and Mcl-1 in response to the mitochondrial inhibitors and biguanides. In conclusion, our results suggest that increased mitochondrial oxidative metabolism upregulates the sensitivity of HCC to biguanide drugs. Enhancing the mitochondrial oxidative metabolism in combination with biguanide drugs may be a therapeutic strategy for HCC. PMID:26133123

  13. [Preventing nosocomial infections. Dressings soaked in polyhexamethylene biguanide (PHMB)].

    PubMed

    Salas Campos, Luis; Gómez Ferrero, Ona; Estudillo Pérez, Vanesa; Fernández Mansilla, Marta

    2006-06-01

    Polyhexamethlene biguanide (PHMB) is an antibacterial agent included in the chlorhexidine group which is active against a wide number of microorganisms including Staphylococcus Aureus Methycilin Resistant (MRSA), Vancomycin Resistant Enterococcus Faecalis (VRE) and Acinetobacter baumannii which all cause antibiotic-resistant infections. Traditionally gauze dressings have been used to cover and protect wounds although their porous structure does not constitute an efficient barrier against bacterial penetration, especially when a dressing becomes wet due to the effects of a wound oozing and draining. Recently the use of a dressing soaked in a 0.2% PHMB solution which works as a biological barrier against pathogenic agents has been introduced in clinical practice. On the one hand, this PHMB soaked dressing inhibits bacterial growth in the areas where it is applied and, on the other hand, it prevents the penetration of microorganisms through the dressing itself. Simultaneously while a PHMB soaked dressing carries out these actions, it creates an environment favorable to the proliferation of the normal flora found in the epidermis. As opposed to porous gauze dressings, a PHMB dressing remains active during 72 hours even in wet environs. Its wide anti-micro-bacterial range prevents infections in surgical, acute or chronic wounds and in any type of intra-corporal access susceptible to infection, such as by means of intravascular catheters, tracheotomies, or thoracic tubes. A PHMB dressing can also be used as a primary covering to treat a chronic wound since it does not interfere in the process of tissue reepithelization. PMID:16875365

  14. Chemicals from coal. Utilization of coal-derived phenolic compounds

    SciTech Connect

    Song, C.; Schobert, H.H.

    1999-07-01

    This article provides an overview for possible utilization of coal-derived phenolic compounds. Phenolic compounds are abundant in coal-derived liquids. Coal-derived phenolic compounds include phenol, cresol, catechol, methylcatechol, naphthol, and their derivatives. Liquids from coal liquefaction, pyrolysis, gasification, and carbonization are potential sources of phenolic chemicals, although certain processing and separation are needed. There are opportunities for coal-based phenolic chemicals, because there are existing industrial applications and potential new applications. Currently the petrochemical industry produces phenol in multi-step processes, and new research and development has resulted in a one-step process. Selective methylation of phenol can produce a precursor for aromatic engineering plastics. Catalytic oxidation of phenol has been commercialized recently for catechol production. There are potential new uses of phenol that could replace large-volume multi-step chemical processes that are based on benzene as the starting material. New chemical research on coal and coal-derived liquids can pave the way for their non-fuel uses for making chemicals and materials.

  15. Evaluation of novel hydrophilic derivatives for chemically amplified EUV resists

    NASA Astrophysics Data System (ADS)

    Tanagi, Hiroyuki; Tanaka, Hiroyasu; Hayakawa, Shoichi; Furukawa, Kikuo; Yamamoto, Hiroki; Kozawa, Takahiro

    2014-03-01

    EUV lithography is the most favorable process for high volume manufacturing of semiconductor devices beyond 1X nm half-pitch. Many efforts have revealed effective proton sources in acid generation in EUV resists, and the effective proton generation and the control of the generated acid diffusion are required to improve the breakthrough of the resolution ? line width roughness ? sensitivity(RLS) trade-off. To clarify the lithographic performance of these derivatives, we synthesized the acrylic terpolymers containing novel hydrophilic derivatives as model photopolymers and exposed the resist samples based on these polymers to EUV and EB radiation. On the basis of the lithographic performances of these resist samples, we evaluated the characteristics of hydrophilic derivatives upon exposure to EUV radiation. We discuss the relationship between the chemical structures of these derivatives and lithographic performance.

  16. Evaluation of novel lactone derivatives for chemically amplified EUV resists

    NASA Astrophysics Data System (ADS)

    Tanaka, Hiroyasu; Mizusaka, Tetsuhiko; Tanagi, Hiroyuki; Furukawa, Kikuo; Yamamoto, Hiroki; Kozawa, Takahiro

    2015-03-01

    EUV lithography is the most favorable process for high volume manufacturing of semiconductor devices beyond 1X nm half-pitch at present. Many efforts have revealed effective proton sources in acid generation in EUV resists, and the effective proton generation and the control of the generated acid diffusion are required to improve the breakthrough of the resolution ? line width roughness ? sensitivity(RLS) trade-off. To clarify the lithographic performance of these derivatives, we synthesized the acrylic ter/tetrapolymers containing novel lactone derivatives - LCHO and LAATB - as model photopolymers and exposed the resist samples based on these polymers to EUV and EB radiation. On the basis of the lithographic performances of these photoresists, we evaluated the characteristics of lactone derivatives upon exposure to EUV radiation. We discuss the relationship between the chemical structures of these derivatives and lithographic performance.

  17. Study on resist performance of chemically amplified molecular resist based on noria derivative and calixarene derivative

    NASA Astrophysics Data System (ADS)

    Yamamoto, Hiroki; Kudo, Hiroto; Kozawa, Takahiro

    2014-03-01

    Novel resist materials are required for lithographic processing with ionization radiation such as extreme ultraviolet (EUV) and electron beam (EB) exposure tool. In this study, we developed positive-tone chemically amplified molecular resists based on noria derivatives and calixarene derivatives and evaluated the lithographic performance using EUV and EB. We make clear that a small change in modification of noria resists can cause a significant change of sensitivity. Especially, it is useful for the improvement of resist sensitivities to use protecting groups such as 2-acetyloxy-2-methyladamantyl ester (AD) groups and ethoxy groups. Also, novel calixarene derivative such as pillar[5]arene protected by AD showed a semi-isolated pattern with the line width of 40 nm (pitch: 100nm). Noria derivatives and calixarene derivative resists were promising candidates because of high sensitivity, high resolution and etch durability similar to conventional resist such as ZEP 520A and UVIII.

  18. Analytical Derivation of Moment Equations in Stochastic Chemical Kinetics

    PubMed Central

    Sotiropoulos, Vassilios; Kaznessis, Yiannis N.

    2011-01-01

    The master probability equation captures the dynamic behavior of a variety of stochastic phenomena that can be modeled as Markov processes. Analytical solutions to the master equation are hard to come by though because they require the enumeration of all possible states and the determination of the transition probabilities between any two states. These two tasks quickly become intractable for all but the simplest of systems. Instead of determining how the probability distribution changes in time, we can express the master probability distribution as a function of its moments, and, we can then write transient equations for the probability distribution moments. In 1949, Moyal defined the derivative, or jump, moments of the master probability distribution. These are measures of the rate of change in the probability distribution moment values, i.e. what the impact is of any given transition between states on the moment values. In this paper we present a general scheme for deriving analytical moment equations for any N-dimensional Markov process as a function of the jump moments. Importantly, we propose a scheme to derive analytical expressions for the jump moments for any N-dimensional Markov process. To better illustrate the concepts, we focus on stochastic chemical kinetics models for which we derive analytical relations for jump moments of arbitrary order. Chemical kinetics models are widely used to capture the dynamic behavior of biological systems. The elements in the jump moment expressions are a function of the stoichiometric matrix and the reaction propensities, i.e the probabilistic reaction rates. We use two toy examples, a linear and a non-linear set of reactions, to demonstrate the applicability and limitations of the scheme. Finally, we provide an estimate on the minimum number of moments necessary to obtain statistical significant data that would uniquely determine the dynamics of the underlying stochastic chemical kinetic system. The first two moments only provide limited information, especially when complex, non-linear dynamics are involved. PMID:21949443

  19. Biguanide-functionalized mesoporous SBA-15 silica as an efficient solid catalyst for interesterification of vegetable oils.

    PubMed

    Xie, Wenlei; Hu, Libing

    2016-04-15

    The biguanide-functionalized SBA-15 materials were fabricated by grafting of organic biguanide onto the SBA-15 silica through covalent attachments, and then this organic-inorganic hybrid material was employed as solid catalysts for the interesterification of triacylglycerols for the modification of vegetable oils. The prepared catalyst was characterized by FTIR, XRD, SEM, TEM, nitrogen adsorption-desorption and elemental analysis. The biguanide base was successfully tethered onto the SBA-15 silica with no damage to the ordered mesoporous structure of the silica after the organo-functionalization. The solid catalyst had stronger base strength and could catalyze the interesterification of triacylglycerols. The fatty acid compositions and triacylglycerol profiles of the interesterified products were noticeably varied following the interesterification. The reaction parameters, namely substrate ratio, reaction temperature, catalyst loading and reaction time, were investigated for the interesterification of soybean oil with methyl decanoate. The catalyst could be reused for at least four cycles without significant loss of activity. PMID:26616928

  20. 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

  1. Revisiting Aromaticity and Chemical Bonding of Fluorinated Benzene Derivatives

    PubMed Central

    Torres-Vega, Juan J; Vásquez-Espinal, Alejandro; Ruiz, Lina; Fernández-Herrera, María A; Alvarez-Thon, Luis; Merino, Gabriel; Tiznado, William

    2015-01-01

    The electron delocalization of benzene (C6H6) and hexafluorobenzene (C6F6) was analyzed in terms of the induced magnetic field, nucleus-independent chemical shift (NICS), and ring current strength (RCS). The computed out-of-plane component of the induced magnetic field at a distance (r) greater than or equal to 1.0?Å above the ring center correlates well (R2>0.99) with the RCS value. According to these criteria, fluorination has two effects on the C6 skeleton; concomitantly, the resonant effects diminish the ? electron delocalization and the inductive effects decrease the charge density at the ring center and therefore reduce the magnitude of the paratropic current generated in this region. The equilibrium between both effects decreases aromaticity in the fluorinated benzene derivatives. These results can be extrapolated to determine the aromaticity of any derivative within the series of fluorinated benzene derivatives (C6H(6?n)Fn, where n=1–5). PMID:26246992

  2. Metabolic determinants of cancer cell sensitivity to glucose limitation and biguanides

    NASA Astrophysics Data System (ADS)

    Birsoy, K?vanç; Possemato, Richard; Lorbeer, Franziska K.; Bayraktar, Erol C.; Thiru, Prathapan; Yucel, Burcu; Wang, Tim; Chen, Walter W.; Clish, Clary B.; Sabatini, David M.

    2014-04-01

    As the concentrations of highly consumed nutrients, particularly glucose, are generally lower in tumours than in normal tissues, cancer cells must adapt their metabolism to the tumour microenvironment. A better understanding of these adaptations might reveal cancer cell liabilities that can be exploited for therapeutic benefit. Here we developed a continuous-flow culture apparatus (Nutrostat) for maintaining proliferating cells in low-nutrient media for long periods of time, and used it to undertake competitive proliferation assays on a pooled collection of barcoded cancer cell lines cultured in low-glucose conditions. Sensitivity to low glucose varies amongst cell lines, and an RNA interference (RNAi) screen pinpointed mitochondrial oxidative phosphorylation (OXPHOS) as the major pathway required for optimal proliferation in low glucose. We found that cell lines most sensitive to low glucose are defective in the OXPHOS upregulation that is normally caused by glucose limitation as a result of either mitochondrial DNA (mtDNA) mutations in complex I genes or impaired glucose utilization. These defects predict sensitivity to biguanides, antidiabetic drugs that inhibit OXPHOS, when cancer cells are grown in low glucose or as tumour xenografts. Notably, the biguanide sensitivity of cancer cells with mtDNA mutations was reversed by ectopic expression of yeast NDI1, a ubiquinone oxidoreductase that allows bypass of complex I function. Thus, we conclude that mtDNA mutations and impaired glucose utilization are potential biomarkers for identifying tumours with increased sensitivity to OXPHOS inhibitors.

  3. Metabolic determinants of cancer cell sensitivity to glucose limitation and biguanides

    PubMed Central

    Birsoy, K?vanç; Possemato, Richard; Lorbeer, Franziska K.; Bayraktar, Erol C.; Thiru, Prathapan; Yucel, Burcu; Wang, Tim; Chen, Walter W.; Clish, Clary B.; Sabatini, David M.

    2014-01-01

    As the concentrations of highly consumed nutrients, particularly glucose, are generally lower in tumours than in normal tissues1,2, cancer cells must adapt their metabolism to the tumour microenvironment. A better understanding of these adaptations might reveal cancer cell liabilities that can be exploited for therapeutic benefit. Here, we developed a continuous flow culture apparatus (Nutrostat) for maintaining proliferating cells in low nutrient media for long periods of time and used it to undertake competitive proliferation assays on a pooled collection of barcoded cancer cell lines cultured in low glucose conditions. Sensitivity to low glucose varies amongst cell lines, and an RNAi screen pinpointed mitochondrial oxidative phosphorylation (OXPHOS) as the major pathway required for optimal proliferation in low glucose. We found that cell lines most sensitive to low glucose are defective in the upregulation of OXPHOS normally caused by glucose limitation as a result of either mtDNA mutations in Complex I genes or impaired glucose utilization. These defects predict sensitivity to biguanides, anti-diabetic drugs that inhibit OXPHOS3,4, when cancer cells are grown in low glucose or as tumour xenografts. Remarkably, the biguanide sensitivity of cancer cells with mtDNA mutations was reversed by ectopic expression of yeast NDI1, a ubiquinone oxidoreductase that allows bypass of Complex I function5. Thus, we conclude that mtDNA mutations and impaired glucose utilization are potential biomarkers for identifying tumours with increased sensitivity to OXPHOS inhibitors. PMID:24670634

  4. 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

  5. Coumarin heterocyclic derivatives: chemical synthesis and biological activity.

    PubMed

    Medina, Fernanda G; Marrero, Joaquín G; Macías-Alonso, Mariana; González, Magdalena C; Córdova-Guerrero, Iván; Teissier García, Ariana G; Osegueda-Robles, Soraya

    2015-09-23

    This review highlights the broad range of science that has arisen from the synthesis of coumarin-linked and fused heterocycle derivatives. Specific topics include their synthesis and biological activity. PMID:26151411

  6. 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

  7. Mucoadhesive system formed by liquid crystals for buccal administration of poly(hexamethylene biguanide) hydrochloride.

    PubMed

    Souza, Carla; Watanabe, Evandro; Borgheti-Cardoso, Livia Neves; De Abreu Fantini, Márcia Carvalho; Lara, Marilisa Guimarães

    2014-12-01

    Antimicrobial approaches are valuable in controlling the development of buccal diseases, but some antibacterial agents have a short duration of activity. Therefore, the development of prolonged delivery systems would be advantageous. Liquid crystalline systems comprising monoolein (GMO)/water have been considered to be a potential vehicle to deliver drugs to the buccal mucosa because of the phase properties that allow for controlled drug release as well as its mucoadhesive properties. Therefore, the aim of this study was to develop a GMO/water system for the slow release of poly(hexamethylene biguanide) hydrochloride (PHMB) on the buccal mucosa and test the properties of this system with regard to swelling, release profile, antimicrobial activity, and strength of mucoadhesion, with the overall goal of treating buccal infections. The tested systems were capable of modulating drug release, which is controlled by diffusion of the drug throughout the system. Furthermore, PHMB appeared to improve the mucoadhesive properties of the system and may synergistically act with the drug to promote antimicrobial activity against S. mutas and C. albicans, indicating that liquid crystals may be suitable for the administration of PHMB on the buccal mucosa. Therefore, this system could be proposed as a novel system for mucoadhesive drug delivery. PMID:25336429

  8. 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) g L(-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 C=O 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

  9. Is it time to test biguanide metformin in the treatment of melanoma?

    PubMed

    Cerezo, Michael; Tomic, Tijana; Ballotti, Robert; Rocchi, Stéphane

    2015-01-01

    Metformin is the most widely used antidiabetic drug that belongs to the biguanide class. It is very well tolerated and has the major clinical advantage of not inducing hypoglycemia. Metformin decreases hepatic glucose production via a mechanism requiring liver kinase B1, which controls the metabolic checkpoint, AMP-activated protein kinase-mammalian target of rapamycin and neoglucogenic genes. The effects of metformin on this pathway results in reduced protein synthesis and cell proliferation. These observations have given the impetus for many investigations on the role of metformin in the regulation of tumor cell proliferation, cell-cycle regulation, apoptosis, and autophagy. Encouraging results from these studies have shown that metformin could potentially be used as an efficient anticancer drug in various neoplasms such as prostate, breast, lung, pancreas cancers, and melanoma. These findings are strengthened by retrospective epidemiological studies that have found a decrease in cancer risk in diabetic patients treated with metformin. In this review, we have focused our discussion on recent molecular mechanisms of metformin that have been described in various solid tumors in general and in melanoma in particular. PMID:24862830

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

    PubMed

    Lennen, Rebecca M; Pfleger, Brian F

    2013-12-01

    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

  11. Opinion of the scientific committee on consumer safety (SCCS) - 2nd Revision of the safety of the use of poly(hexamethylene) biguanide hydrochloride or polyaminopropyl biguanide (PHMB) in cosmetic products.

    PubMed

    Bernauer, Ulrike

    2015-12-01

    Conclusion of the opinion: On the basis of the data available, the SCCS concludes that Polyaminopropyl Biguanide (PHMB) is not safe for consumers when used as a preservative in cosmetic spray formulations and in all cosmetic products up to the maximum concentration of 0.3%. The safe use could be based on a lower use concentration and/or restrictions with regard to cosmetic products' categories. Dermal absorption studies on additional representative cosmetic formulations are needed. PHMB is used in a variety of applications other than cosmetics. General exposure data from sources others than cosmetics should be submitted for the assessment of the aggregate exposure of PHMB. PMID:26456666

  12. Tendencies of 31P chemical shifts changes in NMR spectra of nucleotide derivatives.

    PubMed Central

    Lebedev, A V; Rezvukhin, A I

    1984-01-01

    31P NMR chemical shifts of the selected mono- and oligonucleotide derivatives, including the compounds with P-N, P-C, P-S bonds and phosphite nucleotide analogues have been presented. The influence of substituents upon 31P chemical shifts has been discussed. The concrete examples of 31P chemical shifts data application in the field of nucleotide chemistry have been considered. PMID:6087290

  13. 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.

  14. Photovoltaic Study of Chemically Derived Titanium-Doped Polythiophene Composites

    NASA Astrophysics Data System (ADS)

    Takpire, S. R.; Waghuley, S. A.

    2015-08-01

    In the present work, titanium (Ti)-doped polythiophene (PTh) was synthesized by a chemical route using titanium chloride as oxidant. As-synthesized composites were further used for fabrication of photovoltaic (PV) cells with indium tin oxide/Ti-doped PTh/aluminum architecture. Structural, morphological, and optical analyses of as-synthesized composites were carried out through x-ray diffraction (XRD) analysis, Fourier-transform infrared (FTIR) spectroscopy, field-emission scanning electron microscopy (FE-SEM), ultraviolet-visible (UV-Vis) spectroscopy, and photoluminescence (PL) measurements. A broad peak was found in the PL spectra of the composites at around 480 nm, indicating high charge generation efficiency. Different PV parameters of the fabricated PV cells were measured at room temperature under incandescent light of 100 W/m2. The optimized PV cell exhibited short-circuit current ( I sc) and open-circuit voltage ( V oc) on the order of 176 ?A and 0.595 V, respectively. The values of I sc and V oc were used to compute the fill factor, which was found to be 0.521. The corresponding power conversion efficiency associated with the optimized cell was found to be 2.41%.

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

    SciTech Connect

    Nenov, Artur; Vivie-Riedle, Regina de

    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.

  16. Gram-positive bacteria as biocatalysts to convert biomass derived sugars into biofuel and chemicals

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The microbial fermentation of biomass derived sugar mixtures is one of the barriers to the overall economic conversion process from lignocellulosic biomass to fuels and chemicals. Although the supply and characteristics of feedstocks vary, biomass hydrolysates usually contain mixed sugars, organic ...

  17. 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.

  18. Development of novel protecting derivatives for chemically amplified extreme ultraviolet resist

    NASA Astrophysics Data System (ADS)

    Tanaka, Hiroyasu; Tanagi, Hiroyuki; Hayakawa, Shoichi; Furukawa, Kikuo; Yamamoto, Hiroki; Kozawa, Takahiro

    2014-03-01

    EUV lithography is the most favorable process for high volume manufacturing of semiconductor devices below 1X nm half-pitch. Many efforts have revealed that the effective proton generation and the control of the generated acid diffusion are required to improve the breakthrough of the RLS trade-off. For the development of EUV resists, the novel protecting derivatives were designed. To clarify the lithographic performance of these derivatives, we synthesized the acrylic polymers containing these derivatives as model photopolymers and exposed the resist samples based on these polymers to EUV/EB radiation. On the basis of the lithographic performances of these resist sample, we evaluated the characteristics of novel protecting derivatives upon exposure to EUV/EB radiation. We discuss the relationship between the chemical structures of these derivatives and lithographic performance.

  19. Identification of a thienopyrimidine derivatives target by a kinome and chemical biology approach.

    PubMed

    Lee, Chulho; Yang, Jee Sun; Han, Gyoonhee

    2015-09-01

    Target identification through chemical biology has been considered one of the most efficient approaches for drug discovery. Thienopyrimidine derivatives were designed to discover potent I?B kinase ? (IKK?) inhibitors based on a known IKK? inhibitor library. Most of the thienopyrimidine derivatives inhibited nitric oxide and tumor necrosis factor alpha, which are downstream of the NF-?B signaling pathway, but not IKK?. To identify the appropriate targets of thienopyrimidine analogues, chemical biology approaches, including text mining and a subsequent kinase panel assay from the kinome profiling were used. Based on the results, Fms-like tyrosine kinase 3 was found to be the target for thienopyrimidine derivatives, and was confirmed to be a potent inhibitor for acute myeloid leukemia. PMID:26186885

  20. Effects of Chemical Weathering on TIR-Derived Bulk Compositions From Deconvolution Models of Mineral Mixtures

    NASA Astrophysics Data System (ADS)

    Rampe, E. B.; Kraft, M. D.; Sharp, T. G.; Rogers, A. D.

    2007-12-01

    The Martian surface may be chemically altered on regional scales. Thermal infrared (TIR) spectroscopy and spectral deconvolution are commonly used to determine mineral abundances of the surface. Chemically weathered surfaces tend to be intimate mixtures of igneous minerals and fine-grained alteration products. To understand how alteration products affect deconvolution models of TIR spectra and model-derived bulk compositions, we measured TIR spectra of physical mineral mixtures, composed of an igneous component (augite, andesine, or 50-50 weight percent augite-andesine) and an alteration phase (montmorillonite clay or synthetic amorphous silica). Weathering products can cause significant differences between the actual and the modeled primary igneous mineral abundances and cause the false identification of significant amounts of volcanic glass in deconvolution models (Rampe et al., 2007). We calculated the bulk oxide compositions (Hamilton et al., 2000) from spectral model results of our physical mixtures and compared them to the actual bulk compositions of the mixtures. Previous studies have shown that bulk chemical compositions can be derived from TIR spectral model results (Hamilton et al., 2001; Wyatt et al., 2001), and bulk oxide data of the Martian surface are commonly derived from spectral models of data from the Thermal Emission Spectrometer (TES) (Hamilton et al., 2001; Hurowitz et al., 2007). In alkali-vs.-SiO2 plots, model-derived compositions for clay- bearing mixtures were similar to the actual compositions of the mixtures; however, model-derived compositions for silica-bearing mixtures varied significantly from the actual values of the mixtures. In Al2O3-vs.- (CaO+Na2O+K2O)-vs.-(FeO+MgO) ternary plots, the model-derived compositions of clay-bearing mixtures followed trends typical of terrestrial basalt weathering, whereas the model-derived compositions for silica-bearing mixtures followed trends seen in compositional data derived from TES spectra from Mars (Hurowitz et al., 2007). Our data show that chemical weathering and precipitation of amorphous silica may account for some of the chemical variations of rocks on Mars as derived from TES spectral data.

  1. 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

  2. Prediction of Henry's law constants of triazine derived herbicides from quantum chemical continuum solvation models.

    PubMed

    Delgado, Eduardo J; Alderete, Joel B

    2003-01-01

    The Henry's law constants (H) for triazine derived herbicides are calculated using quantum chemical solvation models, SM2, SM3, PCM-DFT, and CPCM-DFT, and their performances are discussed. The results show considerable differences in performance among the different levels of theory. The values of H calculated by the semiempirical methods agree much better with the experimental values than those obtained at the DFT level. The differences are discussed in terms of the different contributions, electrostatic and no-electrostatic, to Gibbs free energy of solvation. In addition, the Henry's law constants of some triazine derived herbicides whose values have not been reported earlier are predicted as well. PMID:12870915

  3. A chemically amplified fullerene-derivative molecular electron-beam resist.

    PubMed

    Gibbons, Francis; Zaid, Hasnah M; Manickam, Mayandithevar; Preece, Jon A; Palmer, Richard E; Robinson, Alex P G

    2007-12-01

    Current lithographic resists depend on large polymeric materials, which are starting to limit further improvements in line-width roughness and feature size. Fullerene molecular resists use much smaller molecules to avoid this problem. However, such resists have poor radiation sensitivity. Chemical amplification of a fullerene derivative using an epoxy crosslinker and a photoacid generator is demonstrated. The sensitivity of the material is increased by two orders of magnitude, and 20-nm line widths are patterned. PMID:18008296

  4. Chemical modulation of chaperone-mediated autophagy by retinoic acid derivatives

    PubMed Central

    Anguiano, Jaime; Garner, Thomas P; Mahalingam, Murugesan; Das, Bhaskar C.; Gavathiotis, Evripidis; Cuervo, Ana Maria

    2013-01-01

    Chaperone-mediated autophagy (CMA) contributes to cellular quality control and the cellular response to stress through the selective degradation of cytosolic proteins in lysosomes. Decrease in CMA activity occurs in aging and in age-related disorders (for example, neurodegenerative diseases and diabetes). Although prevention of this age-dependent decline through genetic manipulation in mouse has proven beneficial, chemical modulation of CMA is not currently possible, due in part to the lack of information on the signaling mechanisms that modulate this pathway. In this work, we report that signaling through the retinoic acid receptor alpha (RAR?) inhibits CMA and apply structure-based chemical design to develop synthetic derivatives of all-trans-retinoic acid (ATRA) to specifically neutralize this inhibitory effect. We demonstrate that chemical enhancement of CMA protects cells from oxidative stress and from proteotoxicity, supporting a potential therapeutic opportunity when reduced CMA contributes to cellular dysfunction and disease. PMID:23584676

  5. Tyrosine-Specific Chemical Modification with in Situ Hemin-Activated Luminol Derivatives.

    PubMed

    Sato, Shinichi; Nakamura, Kosuke; Nakamura, Hiroyuki

    2015-11-20

    Tyrosine-specific chemical modification was achieved using in situ hemin-activated luminol derivatives. Tyrosine residues in peptide and protein were modified effectively with N-methylated luminol derivatives under oxidative conditions in the presence of hemin and H2O2. Both single and double modifications of the tyrosine residue occurred in the reaction of angiotensin II with N-methylated luminol derivative 9. Tyrosine-specific chemical modification of the model protein bovine serum albumin (BSA) revealed that the surface-exposed tyrosine residues were selectively modified with 9. We succeeded in the functionalization of several proteins using azide-conjugated compound 18 using alkyne-conjugated probes by copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC) or dibenzocyclooctyne (DBCO)-mediated copper-free click chemistry. This tyrosine-specific modification was orthogonal to conventional lysine modification by N-hydroxysuccinimide (NHS) ester, and dual functionalization by fluorescence modification of tyrosine residues and PEG modification of lysine residues was achieved without affecting the modification efficiency. PMID:26356088

  6. 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.

  7. LOAD TRANSFER AND MECHANICAL PROPERTIES OF CHEMICALLY DERIVED SINGLE LAYER GRAPHENE REINFORCEMENTS IN POLYMER COMPOSITES

    PubMed Central

    Xu, Peng; Loomis, James; Panchapakesan, Balaji

    2013-01-01

    We report load transfer and mechanical properties of chemically derived single layer graphene (SLG) as reinforcements in poly (dimethyl) siloxane (PDMS) composites. Mixing single layer graphene in polymers resulted in the marked decrease of the G’ or 2D band intensity due to doping and functionalization. A Raman G mode shift of 11.2 cm?1/% strain in compression and 4.2 cm?1/% strain in tension is reported. An increase in elastic modulus of PDMS by ~42%, toughness by ~39%, damping capability by ~673%, and strain energy density of ~43% by the addition of 1 wt. % SLG in PDMS is reported. PMID:23196792

  8. 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.

  9. 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.

  10. Hydrodeoxygenation processes: advances on catalytic transformations of biomass-derived platform chemicals into hydrocarbon fuels.

    PubMed

    De, Sudipta; Saha, Basudeb; Luque, Rafael

    2015-02-01

    Lignocellulosic biomass provides an attractive source of renewable carbon that can be sustainably converted into chemicals and fuels. Hydrodeoxygenation (HDO) processes have recently received considerable attention to upgrade biomass-derived feedstocks into liquid transportation fuels. The selection and design of HDO catalysts plays an important role to determine the success of the process. This review has been aimed to emphasize recent developments on HDO catalysts in effective transformations of biomass-derived platform molecules into hydrocarbon fuels with reduced oxygen content and improved H/C ratios. Liquid hydrocarbon fuels can be obtained by combining oxygen removal processes (e.g. dehydration, hydrogenation, hydrogenolysis, decarbonylation etc.) as well as by increasing the molecular weight via C-C coupling reactions (e.g. aldol condensation, ketonization, oligomerization, hydroxyalkylation etc.). Fundamentals and mechanistic aspects of the use of HDO catalysts in deoxygenation reactions will also be discussed. PMID:25443804

  11. 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

  12. 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.

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

    SciTech Connect

    David C. Dayton

    2010-03-24

    Executive Summary The growing gap between petroleum production and demand, mounting environmental concerns, and increasing fuel prices have stimulated intense interest in research and development (R&D) of alternative fuels, both synthetic and bio-derived. Currently, the most technically defined thermochemical route for producing alternative fuels from lignocellulosic biomass involves gasification/reforming of biomass to produce syngas (carbon monoxide [CO] + hydrogen [H2]), followed by syngas cleaning, Fischer-Tropsch synthesis (FTS) or mixed alcohol synthesis, and some product upgrading via hydroprocessing or separation. A detailed techno-economic analysis of this type of process has recently been published [1] and it highlights the need for technical breakthroughs and technology demonstration for gas cleanup and fuel synthesis. The latter two technical barrier areas contribute 40% of the total thermochemical ethanol cost and 70% of the production cost, if feedstock costs are factored out. Developing and validating technologies that reduce the capital and operating costs of these unit operations will greatly reduce the risk for commercializing integrated biomass gasification/fuel synthesis processes for biofuel production. The objective of this project is to develop and demonstrate new catalysts and catalytic processes that can efficiently convert biomass-derived syngas into diesel fuel and C2-C4 alcohols. The goal is to improve the economics of the processes by improving the catalytic activity and product selectivity, which could lead to commercialization. The project was divided into 4 tasks: Task 1: Reactor Systems: Construction of three reactor systems was a project milestone. Construction of a fixed-bed microreactor (FBR), a continuous stirred tank reactor (CSTR), and a slurry bubble column reactor (SBCR) were completed to meet this milestone. Task 2: Iron Fischer-Tropsch (FT) Catalyst: An attrition resistant iron FT catalyst will be developed and tested. Task 3: Chemical Synthesis: Promising process routes will be identified for synthesis of selected chemicals from biomass-derived syngas. A project milestone was to select promising mixed alcohol catalysts and screen productivity and performance in a fixed bed micro-reactor using bottled syngas. This milestone was successfully completed in collaboration withour catalyst development partner. Task 4: Modeling, Engineering Evaluation, and Commercial Assessment: Mass and energy balances of conceptual commercial embodiment for FT and chemical synthesis were completed.

  14. Effects of disorder on the transport properties of chemically derived graphene

    NASA Astrophysics Data System (ADS)

    Eda, Goki; Ball, James; Xiao, Ye; Maher, Robert; Cohen, Lesley; Anthopoulos, Thomas; Chhowalla, Manish

    2011-03-01

    Transport properties of chemically derived graphene (CDG) are strongly influenced by the concentration of defects that are introduced during synthesis. We present a comprehensive transport study on a range of CDG films with varying degrees of disorder. The electric properties of CDG were found to be tunable over several orders of magnitude via controlled oxidation and reduction. The structural properties of CDG were monitored by analyzing the defect-related features in the Raman spectra and correlated with transport. The temperature dependence of the resistivity of these samples indicate that the conduction mechanism evolves from tunneling to hopping for strongly disordered samples and to activated transport for weakly disordered samples. Strong disorder causes localization of carriers and field-dependent modulation of hopping conduction. We discuss the temperature- and gate-bias-dependence of the resistivity of weakly disordered samples in terms of scattering dominated by midgap states, as is the case in ion irradiated graphene.

  15. Analytical characterization of plasma membrane-derived vesicles produced via osmotic and chemical vesiculation.

    PubMed

    Sarabipour, Sarvenaz; Chan, Robin B; Zhou, Bowen; Di Paolo, Gilbert; Hristova, Kalina

    2015-07-01

    Plasma membrane-derived vesicles are being used in biophysical and biochemical research as a simple, yet native-like model of the cellular membrane. Here we report on the characterization of vesicles produced via two different vesiculation methods from CHO and A431 cell lines. The first method is a recently developed method which utilizes chloride salts to induce osmotic vesiculation. The second is a well established chemical vesiculation method which uses DTT and formaldehyde. We show that both vesiculation methods produce vesicles which contain the lipid species previously reported in the plasma membrane of these cell lines. The two methods lead to small but statistically significant differences in two lipid species only; phosphatidylcholine (PC) and plasmalogen phosphatidylethanolamine (PEp). However, highly significant differences were observed in the degree of incorporation of a membrane receptor and in the degree of retention of soluble cytosolic proteins within the vesicles. PMID:25896659

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

    PubMed Central

    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

  17. Ag electrode modified with polyhexamethylene biguanide stabilized silver nanoparticles: a new type of SERS substrates for detection of enzymatically generated thiocholine

    NASA Astrophysics Data System (ADS)

    Tepanov, A. A.; Nechaeva, N. L.; Prokopkina, T. A.; Kudrinskiy, A. A.; Kurochkin, I. N.; Lisichkin, G. V.

    2015-11-01

    The detection of thiocholine is one of the most widespread techniques for estimation of the cholinesterase activity – acetylcholinesterase and butyrylcholinesterase. Both cholinesterases can be inhibited by organophosphates and carbamates and accordingly can be considered for estimation of these pollutants in the environment. In the current work, SERS spectroscopy was applied for the thiocholine detection. The Ag electrodes modified with silver nanoparticles stabilized by polyhexamethylene biguanide were for the first time suggested as SERS-substrates for that purpose. Such electrodes can be applicable for SERS detection of submicromolar concentrations of thiocholine.

  18. Investigation of reports of sexual dysfunction among male chemical workers manufacturing stilbene derivatives

    SciTech Connect

    Quinn, M.M.; Wegman, D.H.; Greaves, I.A.; Hammond, S.K.; Ellenbecker, M.J.; Spark, R.F.; Smith, E.R. )

    1990-01-01

    A Health Hazard Evaluation was conducted by the National Institute for Occupational Safety and Health in an area of a large chemical plant that manufactured the stilbene derivative 4,4'-diaminostilbene-2,2'-disulfonic acid, an intermediate used for the production of optical brightening agents. Men employed in the area reported problems with impotence. The study population consisted of 44 men aged 20-57 years (mean age 37) employed in the area at the time of the evaluation. An industrial hygiene investigation, health and work history questionnaire survey, physical examinations, and blood chemistry and serum hormone evaluation were conducted. Fourteen percent of the men reported symptoms of impotence over the preceding 6 or more months, 7% had potency problems of shorter duration, and 7% were not currently impotent but had experienced impotence for 6 or more months in the past; 36% experienced decreased libido, all since beginning work in the production area. Low levels of serum testosterone (less than 350 ng/dl) were observed in 37% of the men. The low serum testosterone concentrations were not accounted for fully by diurnal variation or an effect of rotating shift work. It is suggested that exposures to chemicals possessing estrogenic activity may be related to the observed health effects in these workers.

  19. Optimizing Performance Parameters of Chemically-Derived Graphene/p-Si Heterojunction Solar Cell.

    PubMed

    Batra, Kamal; Nayak, Sasmita; Behura, Sanjay K; Jani, Omkar

    2015-07-01

    Chemically-derived graphene have been synthesized by modified Hummers method and reduced using sodium borohydride. To explore the potential for photovoltaic applications, graphene/p-silicon (Si) heterojunction devices were fabricated using a simple and cost effective technique called spin coating. The SEM analysis shows the formation of graphene oxide (GO) flakes which become smooth after reduction. The absence of oxygen containing functional groups, as observed in FT-IR spectra, reveals the reduction of GO, i.e., reduced graphene oxide (rGO). It was further confirmed by Raman analysis, which shows slight reduction in G-band intensity with respect to D-band. Hall effect measurement confirmed n-type nature of rGO. Therefore, an effort has been made to simu- late rGO/p-Si heterojunction device by using the one-dimensional solar cell capacitance software, considering the experimentally derived parameters. The detail analysis of the effects of Si thickness, graphene thickness and temperature on the performance of the device has been presented. PMID:26373050

  20. Plasmid-derived DNA Strand Displacement Gates for Implementing Chemical Reaction Networks

    PubMed Central

    Chen, Yuan-Jyue; Rao, Sundipta D.; Seelig, Georg

    2015-01-01

    DNA nanotechnology requires large amounts of highly pure DNA as an engineering material. Plasmid DNA could meet this need since it is replicated with high fidelity, is readily amplified through bacterial culture and can be stored indefinitely in the form of bacterial glycerol stocks. However, the double-stranded nature of plasmid DNA has so far hindered its efficient use for construction of DNA nanostructures or devices that typically contain single-stranded or branched domains. In recent work, it was found that nicked double stranded DNA (ndsDNA) strand displacement gates could be sourced from plasmid DNA. The following is a protocol that details how these ndsDNA gates can be efficiently encoded in plasmids and can be derived from the plasmids through a small number of enzymatic processing steps. Also given is a protocol for testing ndsDNA gates using fluorescence kinetics measurements. NdsDNA gates can be used to implement arbitrary chemical reaction networks (CRNs) and thus provide a pathway towards the use of the CRN formalism as a prescriptive molecular programming language. To demonstrate this technology, a multi-step reaction cascade with catalytic kinetics is constructed. Further it is shown that plasmid-derived components perform better than identical components assembled from synthetic DNA. PMID:26649734

  1. Role of Environmental Chemicals, Processed Food Derivatives, and Nutrients in the Induction of Carcinogenesis.

    PubMed

    Persano, Luca; Zagoura, Dimitra; Louisse, Jochem; Pistollato, Francesca

    2015-10-15

    In recent years it has been hypothesized that cancer stem cells (CSCs) are the actual driving force of tumor formation, highlighting the need to specifically target CSCs to successfully eradicate cancer growth and recurrence. Particularly, the deregulation of physiological signaling pathways controlling stem cell proliferation, self-renewal, differentiation, and metabolism is currently considered as one of the leading determinants of cancer formation. Given their peculiar, slow-dividing phenotype and their ability to respond to multiple microenvironmental stimuli, stem cells appear to be more susceptible to genetic and epigenetic carcinogens, possibly undergoing mutations resulting in tumor formation. In particular, some animal-derived bioactive nutrients and metabolites known to affect the hormonal milieu, and also chemicals derived from food processing and cooking, have been described as possible carcinogenic factors. Here, we review most recent literature in this field, highlighting how some environmental toxicants, some specific nutrients and their secondary products can induce carcinogenesis, possibly impacting stem cells and their niches, thus causing tumor growth. PMID:26176180

  2. Poromechanics Parameters of Fluid-Saturated Chemically Active Fibrous Media Derived from a Micromechanical Approach.

    PubMed

    Misra, Anil; Parthasarathy, Ranganathan; Singh, Viraj; Spencer, Paulette

    2013-01-01

    The authors have derived macroscale poromechanics parameters for chemically active saturated fibrous media by combining microstructure-based homogenization with Hill's volume averaging. The stress-strain relationship of the dry fibrous media is first obtained by considering the fiber behavior. The constitutive relationships applicable to saturated media are then derived in the poromechanics framework using Hill's Lemmas. The advantage of this approach is that the resultant continuum model assumes a form suited to study porous materials, while retaining the effect of discrete fiber deformation. As a result, the model is able to predict the influence of microscale phenomena such as fiber buckling on the overall behavior, and in particular, on the poromechanics constants. The significance of the approach is demonstrated using the effect of drainage and fiber nonlinearity on monotonic compressive stress-strain behavior. The model predictions conform to the experimental observations for articular cartilage. The method can potentially be extended to other porous materials such as bone, clays, foams, and concrete. PMID:25419475

  3. Electrocatalytic processing of renewable biomass-derived compounds for production of chemicals, fuels and electricity

    NASA Astrophysics Data System (ADS)

    Xin, Le

    The dual problems of sustaining the fast growth of human society and preserving the environment for future generations urge us to shift our focus from exploiting fossil oils to researching and developing more affordable, reliable and clean energy sources. Human beings had a long history that depended on meeting our energy demands with plant biomass, and the modern biorefinery technologies realize the effective conversion of biomass to production of transportation fuels, bulk and fine chemicals so to alleviate our reliance on fossil fuel resources of declining supply. With the aim of replacing as much non-renewable carbon from fossil oils with renewable carbon from biomass as possible, innovative R&D activities must strive to enhance the current biorefinery process and secure our energy future. Much of my Ph.D. research effort is centered on the study of electrocatalytic conversion of biomass-derived compounds to produce value-added chemicals, biofuels and electrical energy on model electrocatalysts in AEM/PEM-based continuous flow electrolysis cell and fuel cell reactors. High electricity generation performance was obtained when glycerol or crude glycerol was employed as fuels in AEMFCs. The study on selective electrocatalytic oxidation of glycerol shows an electrode potential-regulated product distribution where tartronate and mesoxalate can be selectively produced with electrode potential switch. This finding then led to the development of AEMFCs with selective production of valuable tartronate or mesoxalate with high selectivity and yield and cogeneration of electricity. Reaction mechanisms of electrocatalytic oxidation of ethylene glycol and 1,2-propanediol were further elucidated by means of an on-line sample collection technique and DFT modeling. Besides electro-oxidation of biorenewable alcohols to chemicals and electricity, electrocatalytic reduction of keto acids (e.g. levulinic acid) was also studied for upgrading biomass-based feedstock to biofuels while achieving renewable electricity storage. Meanwhile, ORR that is often coupled in AEMFCs on the cathode was investigated on non-PGM electrocatalyst with comparable activity to commercial Pt/C. The electro-biorefinery process could be coupled with traditional biorefinery operation and will play a significant role in our energy and chemical landscape.

  4. 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

  5. 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

  6. Chemical Solution Derived Planarization Layers for Highly Aligned IBAD MgO Templates

    SciTech Connect

    Paranthaman, Mariappan Parans; Aytug, Tolga; Stan, Liliana; Jia, Quanxi; Cantoni, Claudia; Wee, Sung Hun

    2014-01-01

    The main goal of this research is to develop a chemical solution derived planarization layer to fabricate highly aligned IBAD-MgO templates for the development of high temperature superconductor (HTS) based coated conductors. The standard IBAD-MgO template needs an additional electrochemical polishing step of the mechanically polished 50- m-thick Hastelloy C-276 substrates to ensure a flat and smooth surface for subsequent growth of multi-layer buffer architectures, which include: sputtered 80-nm Al2O3; sputtered 7-nm Y2O3; IBAD 10-nm MgO; sputtered 30-nm homo-epi MgO; and sputtered 30-nm LaMnO3 (LMO) layers. We have successfully developed a solution planarization layer that removes the electrochemical polishing step and also acts as a barrier layer. Crack-free, smooth Al2O3 layers were prepared on mechanically polished Hastelloy substrates using a chemical solution process. A nearly 10-15-nm thick Al2O3 layer was formed with each coating and the coating was repeated several times to achieve the desired film thickness with intermediate heat-treatments after each coating. The Al2O3 planarization layer significantly reduced the surface roughness of the substrate. The average surface roughness value, Ra for a starting substrate was 9-10 nm. After 8 coatings of Al2O3 layer, the Ra was reduced to 2 nm. Highly aligned IBAD-MgO layers with out-of-plane and in-plane textures comparable to the standard IBAD-MgO layers were successfully deposited on top of the solution planarization Al2O3 layers with an Y2O3 nucleation layer using a reel-to-reel ion-beam sputtering system. Both homo-epi MgO and LMO layers were subsequently deposited on the IBAD-MgO layers using rf sputtering to complete the buffer stack required for the growth of HTS films. YBa2Cu3O7- (YBCO) films with a thickness of 0.8 m deposited on these IBAD-MgO templates by pulsed laser deposition showed a high self-field critical current density, Jc of 3.04 MA/cm2 at 77 K and 6.05 MA/cm2 at 65 K. These results demonstrate that a low-cost chemical-solution-based, high-throughput Al2O3 planarization layer can remove the electro-polishing step and replace sputtered Al2O3 layers for the production of high Jc YBCO-coated conductors.

  7. The Nemertine Toxin Anabaseine and Its Derivative DMXBA (GTS-21): Chemical and Pharmacological Properties

    PubMed Central

    Kem, William; Soti, Ferenc; Wildeboer, Kristin; LeFrancois, Susan; MacDougall, Kelly; Wei, Dong-Qing; Chou, Kuo-Chen; Arias, Hugo R.

    2006-01-01

    Nemertines are a phylum of carnivorous marine worms that possess a variety of alkaloidal, peptidic or proteinaceous toxins that serve as chemical defenses against potential predators. The hoplonemertines additionally envenomate their prey with a mixture of proboscis alkaloids delivered with the help of a calcareous stylet that punctures the skin of the victim. Anabaseine, the first of these alkaloids to be identified, stimulates a wide variety of animal nicotinic acetylcholine receptors (AChRs), especially the neuromuscular [e.g., ?12?1?? (embryogenic) or ?12?1?? (adult)] and ?7 AChRs that are inhibited by the snake peptide ?-bungarotoxin. A synthetic derivative, 3-(2,4-Dimethoxybenzylidene)-Anabaseine (DMXBA; also called GTS-21), improves memory in experimental animals and humans and is currently in clinical trials to determine whether it can ameliorate cognitive problems associated with schizophrenia. Here we summarize present knowledge concerning the chemistry and mechanisms of action of these two substances (anabaseine and DMXBA) on AChRs, especially those found in the mammalian brain.

  8. Chemical Characterization of Beer Aging Products Derived from Hard Resin Components in Hops (Humulus lupulus L.).

    PubMed

    Taniguchi, Yoshimasa; Yamada, Makiko; Taniguchi, Harumi; Matsukura, Yasuko; Shindo, Kazutoshi

    2015-11-25

    The bitter taste of beer originates from resins in hops (Humulus lupulus L.), which are classified into two subtypes (soft and hard). Whereas the nature and reactivity of soft-resin-derived compounds, such as ?-, ?-, and iso-?-acids, are well studied, there is only a little information on the compounds in hard resin. For this work, hard resin was prepared from stored hops and investigated for its compositional changes in an experimental model of beer aging. The hard resin contained a series of ?-acid oxides. Among them, 4'-hydroxyallohumulinones were unstable under beer storage conditions, and their transformation induced primary compositional changes of the hard resin during beer aging. The chemical structures of the products, including novel polycyclic compounds scorpiohumulinols A and B and dicyclohumulinols A and B, were determined by HRMS and NMR analyses. These compounds were proposed to be produced via proton-catalyzed cyclization reactions of 4'-hydroxyallohumulinones. Furthermore, they were more stable than their precursor 4'-hydroxyallohumulinones during prolonged storage periods. PMID:26507444

  9. 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

  10. THE JOURNAL OF CHEMICAL PHYSICS 137, 034901 (2012) Derivation of free energy expressions for tube models from

    E-print Network

    Schieber, Jay D.

    2012-01-01

    THE JOURNAL OF CHEMICAL PHYSICS 137, 034901 (2012) Derivation of free energy expressions for tube; accepted 5 June 2012; published online 16 July 2012) We present the free energy of a single-chain mean in the number density of Kuhn steps along the primitive path and in the degree of entanglement. The free energy

  11. 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

  12. Mass production of chemicals from biomass-derived oil by directly atmospheric distillation coupled with co-pyrolysis

    PubMed Central

    Zhang, Xue-Song; Yang, Guang-Xi; Jiang, Hong; Liu, Wu-Jun; Ding, Hong-Sheng

    2013-01-01

    Production of renewable commodity chemicals from bio-oil derived from fast pyrolysis of biomass has received considerable interests, but hindered by the presence of innumerable components in bio-oil. In present work, we proposed and experimentally demonstrated an innovative approach combining atmospheric distillation of bio-oil with co-pyrolysis for mass production of renewable chemicals from biomass, in which no waste was produced. It was estimated that 51.86?wt.% of distillate just containing dozens of separable organic components could be recovered using this approach. Ten protogenetic and three epigenetic compounds in distillate were qualitatively identified by gas chromatography/mass spectrometry and quantified by gas chromatography. Among them, the recovery efficiencies of acetic acid, propanoic acid, and furfural were all higher than 80?wt.%. Formation pathways of the distillate components in this process were explored. This work opens up a fascinating prospect for mass production of chemical feedstock from waste biomass. PMID:23350028

  13. Mass production of chemicals from biomass-derived oil by directly atmospheric distillation coupled with co-pyrolysis

    NASA Astrophysics Data System (ADS)

    Zhang, Xue-Song; Yang, Guang-Xi; Jiang, Hong; Liu, Wu-Jun; Ding, Hong-Sheng

    2013-01-01

    Production of renewable commodity chemicals from bio-oil derived from fast pyrolysis of biomass has received considerable interests, but hindered by the presence of innumerable components in bio-oil. In present work, we proposed and experimentally demonstrated an innovative approach combining atmospheric distillation of bio-oil with co-pyrolysis for mass production of renewable chemicals from biomass, in which no waste was produced. It was estimated that 51.86 wt.% of distillate just containing dozens of separable organic components could be recovered using this approach. Ten protogenetic and three epigenetic compounds in distillate were qualitatively identified by gas chromatography/mass spectrometry and quantified by gas chromatography. Among them, the recovery efficiencies of acetic acid, propanoic acid, and furfural were all higher than 80 wt.%. Formation pathways of the distillate components in this process were explored. This work opens up a fascinating prospect for mass production of chemical feedstock from waste biomass.

  14. Facilitating Biomimetic Syntheses of Borrerine Derived Alkaloids by Means of Flow-Chemical Methods

    E-print Network

    Kamptmann, Sonja B.; Ley, Steven V.

    2014-11-05

    Flow chemistry, although now commonly used for general synthetic chemistry, has not been applied extensively in a biomimetic fashion. Here we show how the flow syntheses of borrerine derived alkaloids can use these principles to obtain complex...

  15. 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.

  16. 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

  17. The applicability of in vitro-derived data in hazard identification and characterisation of chemicals.

    PubMed

    Blaauboer, Bas J

    2002-07-01

    Toxicological hazard and risk assessments for chemicals presently are mainly based on highly standardised protocols for animal experimentation and exposure assessment. In this paper the possibilities are being discussed of developing systems in which the systemic (acute and chronic) toxicity of chemicals can be quantified, without the heavy reliance on animal experiments. On the basis of a chemical's structure, in vitro data on its toxicity, and biokinetic modelling a decision/flow scheme is presented. Key elements are the evaluation of chemical functionalities representing structural alerts for toxic actions, the construction of biokinetic models on the basis of non-animal data (e.g. tissue-blood partition coefficients (PCs), in vitro biotransformation parameters), tests or batteries of tests for determining basal cytotoxicity and more specific tests for evaluating tissue- or organ toxicity. It is concluded that such a flow chart is a useful tool for different steps in the toxicological hazard and risk assessment, especially for those forms of toxicity for which validated in vitro and other non-animal tests have already been developed. PMID:21782605

  18. Influence of pecan-derived biochar on chemical properties of a Norfolk loamy sand soil

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sandy, Coastal Plain soils in the Southeastern USA are low (0.3 to 2%) in soil organic carbon contents (SOC) due to high soil temperatures, abundant rainfall, and a low physico-chemical protection of organic substances. Consequently, the soils have poor soil fertility characteristics. A strategy to ...

  19. 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

  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. Spectroscopic and quantum chemical studies on the structure of 2-arylquinoline-4(1 H)-thione derivatives

    NASA Astrophysics Data System (ADS)

    Mphahlele, Malose J.; El-Nahas, Ahmed M.; El-Gogary, Tarek M.

    2004-03-01

    The geometries of the title compounds were probed in solution, solid and gas states using spectroscopic methods, X-ray crystallography and quantum chemical techniques. The exclusive existence of the NH-4-thiones in solution (NMR and PCM-B3LYP(MP2)/6-31+G(d) calculations) and solid state (FT-IR and X-ray) is also corroborated by comparison of their spectroscopic data with those of the corresponding 2-aryl-1-methylquinoline-4(1 H)-thione derivatives. The co-existence of the quinoline-4-thione and quinoline-4-thiol (4-mercaptoquinoline) isomers in the gas phase is confirmed by mass spectrometry and the preponderance of the 4-thiol is supported by quantum chemical techniques (PM3, MP2 and B3LYP).

  2. Tautomeric 2-arylquinolin-4(1 H)-one derivatives- spectroscopic, X-ray and quantum chemical structural studies

    NASA Astrophysics Data System (ADS)

    Mphahlele, Malose J.; El-Nahas, Ahmed M.

    2004-01-01

    A convenient method for the synthesis of 2-aryl-1-methylquinolin-4(1 H)-ones is described. Spectroscopic and X-ray crystallographic techniques as well as quantum chemical calculations have been used to probe the structure of potentially tautomeric 2-arylquinolin-4(1 H)-ones in solution phase, gas phase and solid state. The exclusive NH-4-oxo nature of the title compounds in solution phase (NMR) and solid state (IR and X-ray) is also corroborated by comparison of their spectroscopic data with those of the corresponding 2-aryl-1-methylquinolin-4(1 H)-one and 2-aryl-4-methoxyquinoline derivatives. Results from mass spectrometric analysis confirm the coexistence of the 4-quinolinone and 4-hydroxyquinoline isomers in the gas phase and this is supported by quantum chemical computations.

  3. A comparison of the chemical and liver extract-induced hepatic differentiation of adipose derived stem cells.

    PubMed

    Nhung, Truong Hai; Nam, Nguyen Hai; Nguyen, Nguyen Thi Kim; Nghia, Huynh; Van Thanh, Nguyen; Ngoc, Phan Kim; Van Pham, Phuc

    2015-11-01

    Adipose-derived stem cells (ADSCs) have been put forward as promising therapeutics for end-stage liver disease (ESLD). In the present study, we compared the effects of defined chemicals and liver extract on the hepatic differentiation of ADSCs. ADSCs were isolated according to the method described in our previously published study. Subsequently, the differentiation of ADSCs was induced separately by chemicals (including hepatic growth factor (HGF), fibroblast growth factor (FGF), and oncostatin M (OSM)) and liver extract (30 ?g/ml) in a total period of 21 d. The efficiency of hepatic differentiation was evaluated by changes in the cell morphology, gene expression, and cellular function. The results showed that the liver extract promoted the hepatic differentiation of ADSCs to a significantly greater extent than the chemicals. In the group of ADSCs treated with liver extract, changes in the cell morphology began sooner, and the expression of alpha-FP and albumin genes was higher than that in the chemically treated group. The ADSCs in both the groups stained positive for anti-alpha trypsin (AAT) and albumin markers. The cells also exhibited glycogen storage capacity. Therefore, we concluded that the liver extract could efficiently induce the differentiation of ADSCs into hepatocyte-like cells. This study reveals the potential of mesenchymal stem cell differentiation in the liver extract, which supports further preclinical and clinical research on the application of ADSCs in ESLD treatment. PMID:26275888

  4. Brain-derived neurotrophic factor as an indicator of chemical neurotoxicity: an animal-free CNS cell culture model.

    PubMed

    Woehrling, Elizabeth K; Hill, Eric J; Nagel, David; Coleman, Michael D

    2013-12-01

    Recent changes to the legislation on chemicals and cosmetics testing call for a change in the paradigm regarding the current 'whole animal' approach for identifying chemical hazards, including the assessment of potential neurotoxins. Accordingly, since 2004, we have worked on the development of the integrated co-culture of post-mitotic, human-derived neurons and astrocytes (NT2.N/A), for use as an in vitro functional central nervous system (CNS) model. We have used it successfully to investigate indicators of neurotoxicity. For this purpose, we used NT2.N/A cells to examine the effects of acute exposure to a range of test chemicals on the cellular release of brain-derived neurotrophic factor (BDNF). It was demonstrated that the release of this protective neurotrophin into the culture medium (above that of control levels) occurred consistently in response to sub-cytotoxic levels of known neurotoxic, but not non-neurotoxic, chemicals. These increases in BDNF release were quantifiable, statistically significant, and occurred at concentrations below those at which cell death was measureable, which potentially indicates specific neurotoxicity, as opposed to general cytotoxicity. The fact that the BDNF immunoassay is non-invasive, and that NT2.N/A cells retain their functionality for a period of months, may make this system useful for repeated-dose toxicity testing, which is of particular relevance to cosmetics testing without the use of laboratory animals. In addition, the production of NT2.N/A cells without the use of animal products, such as fetal bovine serum, is being explored, to produce a fully-humanised cellular model. PMID:24512234

  5. 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.

  6. Efficiency of stepwise magnetic-chemical site assessment for fly ash derived heavy metal pollution

    NASA Astrophysics Data System (ADS)

    Cao, Liwan; Appel, Erwin; Rösler, Wolfgang; Magiera, Tadeusz

    2015-11-01

    Previous works revealed a close relationship between magnetic susceptibility (MS) and heavy metal (HM) contents originating from industrial sources. However, despite general statements on the usefulness of magnetic mapping, the benefit of this procedure for geochemistry was not quantified yet. We present a study on fly ash pollution in soil around a coal-burning power plant complex and simulate a stepwise approach of magnetic pre-screening and subsequent targeted sampling for chemical analysis. The aim of this study is not to discuss correlations between MS and HM, but to show that a combined stepwise magnetic-chemical approach is the most efficient way for outlining HM contamination. In order to provide quantitative evidence, we explored map similarities of spatial HM distributions based on magnetochemical data and chemical data only. We determined 3-D triangular planes defined by categorized HM values at the sampling coordinates and calculated the average dihedral angle of the normal vectors as a similarity result. The study shows that the `Targeted' HM map (selection of 30 sites based magnetic pre-screening) has a higher similarity with the `True' Pollution HM map (85 sites) than HM maps resulting from site selections (30 sites) without using magnetic pre-screening information.

  7. Paleoclimatic significance of chemical weathering in loess-derived paleosols of subarctic central Alaska

    USGS Publications Warehouse

    Muhs, D.R.; Ager, T.A.; Skipp, G.; Beann, J.; Budahn, J.; McGeehin, J.P.

    2008-01-01

    Chemical weathering in soils has not been studied extensively in high-latitude regions. Loess sequences with modern soils and paleosols are present in much of subarctic Alaska, and allow an assessment of present and past chemical weathering. Five sections were studied in detail in the Fairbanks, Alaska, area. Paleosols likely date to mid-Pleistocene interglacials, the last interglacial, and early-to-mid-Wisconsin interstadiale. Ratios of mobile (Na, Ca, Mg, Si) to immobile (Ti or Zr) elements indicate that modern soils and most interstadial and interglacial paleosols are characterized by significant chemical weathering. Na2O/TiO2 is lower in modern soils and most paleosols compared to parent loess, indicating depletion of plagioclase. In the clay fraction, smectite is present in Tanana and Yukon River source sediments, but is absent or poorly expressed in modern soils and paleosols, indicating depletion of this mineral also. Loss of both plagioclase and smectite is well expressed in soils and paleosols as lower SiO 2/TiO2. Carbonates are present in the river source sediments, but based on CaO/TiO2, they are depleted in soils and most paleosols (with one exception in the early-to-mid-Wisconsin period). Thus, most soil-forming intervals during past interglacial and interstadial periods in Alaska had climatic regimes that were at least as favorable to mineral weathering as today, and suggest boreal forest or acidic tundra vegetation. ?? 2008 Regents of the University of Colorado.

  8. 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.

  9. Antibacterial activity of plumbagin derivative-rich Plumbago indica root extracts and chemical stability.

    PubMed

    Kaewbumrung, Sermwut; Panichayupakaranant, Pharkphoom

    2014-01-01

    The extraction studies and a one-step purification of the crude extract of Plumbago indica using silica-gel vacuum chromatography provided a plumbagin derivative-rich P. indica root extract (PPE). The PPE was standardised to contain total plumbagin derivatives not less than 13% w/w. Antibacterial activities of the standardised PPE and three naphthoquinones, plumbagin, elliptinone and 3,3'-biplumbagin, against Propionibacterium acnes, Staphylococcus aureus and Staphylococcus epidermidis were evaluated by using the microdilution assay. The bactericidal activities of the PPE against these bacteria were much stronger than those of elliptinone and 3,3'-biplumbagin and almost equal to those of plumbagin. Stability of the PPE was determined under various conditions through a period of four months. The PPE was stable over a period of four months when stored as a dried powder but only in a well-closed container protected from light under 4 ± 2°C. PMID:24483166

  10. A comprehensive and compact n-heptane oxidation model derived using chemical lumping.

    PubMed

    Ahmed, Syed Sayeed; Mauss, Fabian; Moréac, Gladys; Zeuch, Thomas

    2007-03-01

    A detailed reaction mechanism for n-heptane oxidation has been compiled and subsequently simplified. The model is based on a kinetic model for C1-C4 fuel oxidation of Hoyermann et al. [Phys. Chem. Chem. Phys., 2004, 6, 3824] and a detailed mechanism for n-heptane oxidation developed by Curran et al. [Combust. Flame, 1998, 114, 149]. The generated mechanism is kept compact by limiting the application of the low temperature oxidation pathways to the fuel molecule. The first reaction steps and the complex low temperature paths in the oxidation process have been simplified and reorganized by linear chemical lumping. The reported procedure allows a decrease in number of species and reactions with only a minor loss of model accuracy. The simplified model is of very compact size and gives an advantageous starting point for further model reduction. By this chemically lumped general mechanism without further adjustments the large set of experimental data for the high and low temperature oxidation (ignition delay times, species concentration profiles, heat release and engine pressure profiles, flame speeds and flame structure data) for conditions ranging from very low to high temperatures (550-2300 K), very lean to extremely fuel rich (0.22 < phi < 3) mixtures and pressures between 1 and 42 bar is consistently described providing a basis for reliable predictions for future applications, (i) building reaction mechanisms for similar but chemically more complex fuels (e.g. iso-octane, n-decane,...) and (ii) calculating complex flow fields ("fluid dynamics") after further simplification with advanced reduction tools. PMID:17311154

  11. Activation of the germ-cell potential of human bone marrow-derived cells by a chemical carcinogen

    PubMed Central

    Liu, Chunfang; Ma, Zhan; Xu, Songtao; Hou, Jun; Hu, Yao; Yu, Yinglu; Liu, Ruilai; Chen, Zhihong; Lu, Yuan

    2014-01-01

    Embryonic/germ cell traits are common in malignant tumors and are thought to be involved in malignant tumor behaviors. The reasons why tumors show strong embryonic/germline traits (displaced germ cells or gametogenic programming reactivation) are controversial. Here, we show that a chemical carcinogen, 3-methyl-cholanthrene (3-MCA), can trigger the germ-cell potential of human bone marrow-derived cells (hBMDCs). 3-MCA promoted the generation of germ cell-like cells from induced hBMDCs that had undergone malignant transformation, whereas similar results were not observed in the parallel hBMDC culture at the same time point. The malignant transformed hBMDCs spontaneously and more efficiently generated into germ cell-like cells even at the single-cell level. The germ cell-like cells from induced hBMDCs were similar to natural germ cells in many aspects, including morphology, gene expression, proliferation, migration, further development, and teratocarcinoma formation. Therefore, our results demonstrate that a chemical carcinogen can reactivate the germline phenotypes of human somatic tissue-derived cells, which might provide a novel idea to tumor biology and therapy. PMID:24998261

  12. Chemical modeling of acid-base properties of soluble biopolymers derived from municipal waste treatment materials.

    PubMed

    Tabasso, Silvia; Berto, Silvia; Rosato, Roberta; Marinos, Janeth Alicia Tafur; 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

  13. 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

  14. 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

  15. Identification of persisten anionic surfactant-derived chemicals in sewage effluent and groundwater

    USGS Publications Warehouse

    Field, J.A.; Leenheer, J.A.; Thorn, K.A.; Barber, L.B., II; Rostad, C.; Macalady, D.L.; Daniel, S.R.

    1992-01-01

    Preparative isolation and fractionation procedures coupled with spectrometric analyses were used to identify surfactant-derived contaminants in sewage effluent and sewage-contaminated groundwater from a site located on Cape Cod, Massachusetts. Anionic surfactants and their biodegradation intermediates were isolated from field samples by ion exchange and fractionated by solvent extraction and adsorption chromatography. Fractions were analyzed by 13C nuclear magnetic resonance spectrometry and gas chromatography-mass spectrometry. Carboxylated residues of alkylphenol polyethoxylate surfactants were detected in sewage effluent and contaminated groundwater. Linear alkylbenzenesulfonates (LAS) were identified in sewage effluent and groundwater. Groundwater LAS composition suggested preferential removal of select isomers and homologs due to processes of biodegradation and partitioning. Tetralin and indane sulfonates (DATS), alicyclic analogs of LAS, were also identified in field samples. Although DATS are a minor portion of LAS formulations, equivalent concentrations of LAS and DATS in groundwater suggested persistence of alicyclic contaminant structures over those of linear structure. Sulfophenyl-carboxylated (SPC) LAS biodegradation intermediates were determined in sewage effluent and groundwater. Homolog distributions suggested that SPC containing 3-10 alkyl-chain carbons persist during infiltration and groundwater transport. Surfactant-derived residues detected in well F300-50 groundwater have a minimum residence time in the range of 2.7-4.6 yr. LAS detected in groundwater at 500 m from infiltration has been stable over an estimated 50-500 half lives.

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

    SciTech Connect

    Stewart, M.K.; Lyon, G.L.; Robinson, B.W. ); Glover, R.B. )

    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.

  17. Direct Chemical Vapor Deposition-Derived Graphene Glasses Targeting Wide Ranged Applications.

    PubMed

    Sun, Jingyu; Chen, Yubin; Priydarshi, Manish Kr; Chen, Zhang; Bachmatiuk, Alicja; Zou, Zhiyu; Chen, Zhaolong; Song, Xiuju; Gao, Yanfeng; Rümmeli, Mark H; Zhang, Yanfeng; Liu, Zhongfan

    2015-09-01

    Direct growth of graphene on traditional glasses is of great importance for various daily life applications. We report herein the catalyst-free atmospheric-pressure chemical vapor deposition approach to directly synthesizing large-area, uniform graphene films on solid glasses. The optical transparency and sheet resistance of such kinds of graphene glasses can be readily adjusted together with the experimentally tunable layer thickness of graphene. More significantly, these graphene glasses find a broad range of real applications by enabling the low-cost construction of heating devices, transparent electrodes, photocatalytic plates, and smart windows. With a practical scalability, the present work will stimulate various applications of transparent, electrically and thermally conductive graphene glasses in real-life scenarios. PMID:26305883

  18. 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

  19. 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.

  20. Microbial production of amino acids and derived chemicals: synthetic biology approaches to strain development.

    PubMed

    Wendisch, Volker F

    2014-12-01

    Amino acids are produced at the multi-million-ton-scale with fermentative production of l-glutamate and l-lysine alone being estimated to amount to more than five million tons in the year 2013. Metabolic engineering constantly improves productivities of amino acid producing strains, mainly Corynebacterium glutamicum and Escherichia coli strains. Classical mutagenesis and screening have been accelerated by combination with intracellular metabolite sensing. Synthetic biology approaches have allowed access to new carbon sources to realize a flexible feedstock concept. Moreover, new pathways for amino acid production as well as fermentative production of non-native compounds derived from amino acids or their metabolic precursors were developed. These include dipeptides, ?,?-diamines, ?,?-diacids, keto acids, acetylated amino acids and ?-amino acids. PMID:24922334

  1. The optical properties and quantum chemical calculations of thienyl and furyl derivatives of pyrene.

    PubMed

    Idzik, Krzysztof R; Cywi?ski, Piotr J; Kuznik, Wojciech; Frydel, Jaroslaw; Licha, Tobias; Ratajczyk, Tomasz

    2015-09-21

    A detailed electrochemical, photophysical and theoretical study is presented for various new thienyl and furyl derivatives of pyrene. Their optical properties are described based on UV-VIS absorption and both steady-state and time-resolved fluorescence spectroscopy. DFT and TDDFT calculations are also presented to support experimental data. The calculations results show that HOMO-LUMO orbitals are delocalized uniformly between aromatic core and aryl substituents. Good electrochemical stability of thienyl and furyl hybrids of pyrene confirm their potential application for light emitting electrochemical cells or spintronics mainly due to their beneficial optical and charge transport properties in electrochromic devices. In order to demonstrate this potential, an OLED device is presented. Synthesized compounds included in this OLED device both facilitate electron transport and act as a light emitting layer. PMID:26257127

  2. Chemical profiling of seized methamphetamine putatively synthesized from phenylacetic acid derivatives.

    PubMed

    Tsujikawa, Kenji; Kuwayama, Kenji; Miyaguchi, Hajime; Kanamori, Tatsuyuki; Iwata, Yuko T; Inoue, Hiroyuki

    2013-04-10

    We report a case of seized crystalline methamphetamine (MA) samples showing unique drug profiles. The samples were mainly composed of (S)-(+)-MA, with each containing a slight amount of (R)-(-)-MA (enantiomeric excess: 99.2-99.4%). 1-Phenyl-2-propanol and N-methyl-2-phenylacetamide were detected as characteristic impurities. These analytical results suggested that the samples were synthesized as racemic MA by reductive amination of 1-phenyl-2-propanone, which was synthesized from phenylacetic acid, putatively prepared from phenylacetic acid ester, and then the racemic MA was optically resolved to the (+)-form-rich product. This proposed preparation route was in accordance with recent reports of seizures worldwide of the raw materials of MA such as phenylacetic acid derivatives, methylamine, and tartaric acid (optical resolving reagent). PMID:22989601

  3. Production of levulinic acid and use as a platform chemical for derived products

    SciTech Connect

    Bozell, J.J.; Moens, L.; Elliott, D.C.; Wang, Y.; Neuenscwander, G.G.; Fitzpatrick, S.W.; Bilski, R.J.; Jarnefeld, J.L.

    1999-07-01

    Levulinic acid (LA) can be produced cost effectively and in high yield from renewable feedstocks in a new industrial process. The technology is being demonstrated on a one ton/day scale at a facility in South Glens Falls, New York. Low cost LA can be used as a platform chemical for the production of a wide range of value-added products. This research has demonstrated that LA can be converted to methyltetrahydrofuran (MTHF), a solvent and fuel extender. MTHF is produced in {gt}80% molar yield via a single stage catalytic hydrogenation process. A new preparation of {delta}-aminolevulinic acid (DALA), a broad spectrum herbicide from LA has also been developed. Each step in this new process proceeds in high ({gt}80%) yield and affords DALA (as the hydrochloride salt) in greater than 90% purity, giving a process that could be commercially viable. LA is also being investigated as a starting material for the production of diphenolic acid (DPA), a direct replacement for bisphenol A.

  4. The potential of synthetic indolylquinoline derivatives for A? aggregation reduction by chemical chaperone activity.

    PubMed

    Chang, Kuo-Hsuan; Chiu, Ya-Jen; Chen, Shu-Ling; Huang, Chen-Hsiang; Lin, Chih-Hsin; Lin, Te-Hsien; Lee, Chi-Mei; Ramesh, Chintakunta; Wu, Chung-Hsin; Huang, Chin-Chang; Fung, Hon-Chung; Chen, Yi-Chun; Lin, Jung-Yaw; Yao, Ching-Fa; Huang, Hei-Jen; Lee-Chen, Guey-Jen; Lee, Ming-Chung; Hsieh-Li, Hsiu Mei

    2016-02-01

    Alzheimer's disease (AD) is the most prevalent form of dementia associated with progressive cognitive decline and memory loss. Extracellular ?-amyloid (A?) is a major constituent of senile plaques, one of the pathological hallmarks of AD. A? deposition causes neuronal death via a number of possible mechanisms such as increasing oxidative stress. Therefore therapeutic approaches to identify novel A? aggregate reducers could be effective for AD treatment. Using a Trx-His-A? biochemical assay, we screened 11 synthetic indolylquinoline compounds, and found NC009-1, -2, -6 and -7 displaying potential to reduce A? aggregation. Treating Tet-On A?-GFP 293 cells with these compounds reduced A? aggregation and reactive oxygen species. These compounds also promoted neurite outgrowth in Tet-On A?-GFP SH-SY5Y cells. Furthermore, treatment with above compounds improved neuronal cell viability, neurite outgrowth, and synaptophysin expression level in mouse hippocampal primary culture under oligomeric A?-induced cytotoxicity. Moreover, the tested NC009-1 significantly ameliorated A?-induced inhibition of hippocampal long-term potentiation in mouse hippocampal slices. Our results demonstrate how synthetic indolylquinoline compounds are likely to work as chemical chaperones in A?-aggregation reduction and neuroprotection, providing insight into the possible applications of indolylquinoline compounds in AD treatment. PMID:26362358

  5. Formulation and pharmacokinetics of lipid nanoparticles of a chemically sensitive nitrogen mustard derivative: Chlorambucil.

    PubMed

    Sharma, Puneet; Ganta, Srinivas; Denny, William A; Garg, Sanjay

    2009-02-01

    Lipid nanoparticles of the cancer drug Chlorambucil (CLB) were prepared by ultrasonication, using stearic acid as the core lipid. Four types of lipid nanoparticle formulations were studied: (i) stearic acid solid lipid nanoparticles (SLN); (ii) sterically stabilized SLN with pegylated phospholipids as stabilizer; (iii) nanostructured lipid complexes with oleic acid as adjunct lipid; (iv) lipid nanocomplexes with dimethyl dioctadecyl ammonium bromide (DDAB) as surface modifier (LN). Lipid nanoparticles were characterized for particle size, assay and encapsulation efficiency, particle morphology and physico-chemical stability over 90 days. All of the formulations were physically stable, with an average particle size of 147 (+/-10)nm. The drug encapsulation efficiency (DEE) of all the formulations except LN decreased significantly over time (p<0.05), probably due to the expulsion of CLB upon crystallization. This indicated that the presence of DDAB in stearic acid nanoparticles increases DEE, preventing CLB degradation in the aqueous disperse phase. Pharmacokinetic studies of the intravenous LN formulation revealed plasma clearance kinetics were comparable to that of CLB solution (p>0.01), indicating electrostatic charge mediated clearance, as reported earlier. In tissue and tumor distribution studies, lower AUC values of CLB were observed for LN compared to CLB solution in liver, kidneys, heart and lungs. However, higher AUC values of LN formulation as compared to CLB solution (p<0.01) in tumors suggested that the presence of DDAB on the lipid nanoparticles resulted in greater accumulation of the drug in tumors. PMID:18930127

  6. 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.

  7. Chemical composition and cytotoxicity evaluation of essential oil from leaves of Casearia sylvestris, its main compound ?-zingiberene and derivatives.

    PubMed

    Bou, Diego Dinis; Lago, João Henrique G; Figueiredo, Carlos R; Matsuo, Alisson L; Guadagnin, Rafael C; Soares, Marisi G; Sartorelli, Patricia

    2013-01-01

    Casearia sylvestris (Salicaceae), popularly known as "guaçatonga", is a plant widely used in folk medicine to treat various diseases, including cancer. The present work deals with the chemical composition as well as the cytotoxic evaluation of its essential oil, its main constituent and derivatives. Thus, the crude essential oil from leaves of C. sylvestris was obtained using a Clevenger type apparatus and analyzed by GC/MS. This analysis afforded the identification of 23 substances, 13 of which corresponded to 98.73% of the total oil composition, with sesquiterpene a-zingiberene accounting for 50% of the oil. The essential oil was evaluated for cytotoxic activity against several tumor cell lines, giving IC50 values ranging from 12 to 153 mg/mL. Pure a-zingiberene, isolated from essential oil, was also evaluated against the tumor cell lines showing activity for HeLa, U-87, Siha and HL60 cell lines, but with IC50 values higher than those determined for the crude essential oil. Aiming to evaluate the effect of the double bonds of a-zingiberene on the cytotoxic activity, partially hydrogenated a-zingiberene (PHZ) and fully hydrogenated a-zingiberene (THZ) derivatives were obtained. For the partially hydrogenated derivative only cytotoxic activity to the B16F10-Nex2 cell line (IC50 65 mg/mL) was detected, while totally hydrogenated derivative showed cytotoxic activity for almost all cell lines, with B16F10-Nex2 and MCF-7 as exceptions and with IC50 values ranging from 34 to 65 mg/mL. These results indicate that cytotoxic activity is related with the state of oxidation of compound. PMID:23966073

  8. 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.

  9. 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.

  10. Practical silicon deposition rules derived from silane monitoring during plasma-enhanced chemical vapor deposition

    SciTech Connect

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

    2015-05-28

    We clarify the difference between the SiH{sub 4} consumption efficiency ? and the SiH{sub 4} 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 SiH{sub 4} 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 SiH{sub 4} 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 SiH{sub 4} concentration in the plasma c{sub p}, 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 SiH{sub 4} density measurements throughout the ignition and the termination of a plasma.

  11. 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.

  12. Chemical hydrogels based on a hyaluronic acid-graft-?-elastin derivative as potential scaffolds for tissue engineering.

    PubMed

    Palumbo, Fabio Salvatore; Pitarresi, Giovanna; Fiorica, Calogero; Rigogliuso, Salvatrice; Ghersi, Giulio; Giammona, Gaetano

    2013-07-01

    In this work hyaluronic acid (HA) functionalized with ethylenediamine (EDA) has been employed to graft ?-elastin. In particular a HA-EDA derivative bearing 50 mol% of pendant amino groups has been successfully employed to produce the copolymer HA-EDA-g-?-elastin containing 32% w/w of protein. After grafting with ?-elastin, remaining free amino groups reacted with ethylene glycol diglycidyl ether (EGDGE) for producing chemical hydrogels, proposed as scaffolds for tissue engineering. Swelling degree, resistance to chemical and enzymatic hydrolysis, as well as preliminary biological properties of HA-EDA-g-?-elastin/EGDGE scaffold have been evaluated and compared with a HA-EDA/EGDGE scaffold. The presence of ?-elastin grafted to HA-EDA improves attachment, viability and proliferation of primary rat dermal fibroblasts and human umbilical artery smooth muscle cells. Biological performance of HA-EDA-g-?-elastin/EGDGE scaffold resulted comparable to that of a commercial collagen type I sponge (Antema®), chosen as a positive control. PMID:23623066

  13. Expanding the chemical diversity of natural esters by engineering a polyketide-derived pathway into Escherichia coli.

    PubMed

    Menendez-Bravo, Simón; Comba, Santiago; Sabatini, Martín; Arabolaza, Ana; Gramajo, Hugo

    2014-07-01

    Microbial fatty acid (FA)-derived molecules have emerged as promising alternatives to petroleum-based chemicals for reducing dependence on fossil hydrocarbons. However, native FA biosynthetic pathways often yield limited structural diversity, and therefore restricted physicochemical properties, of the end products by providing only a limited variety of usually linear hydrocarbons. Here we have engineered into Escherichia coli a mycocerosic polyketide synthase-based biosynthetic pathway from Mycobacterium tuberculosis and redefined its biological role towards the production of multi-methyl-branched-esters (MBEs) with novel chemical structures. Expression of FadD28, Mas and PapA5 enzymes enabled the biosynthesis of multi-methyl-branched-FA and their further esterification to an alcohol. The high substrate tolerance of these enzymes towards different FA and alcohol moieties resulted in the biosynthesis of a broad range of MBE. Further metabolic engineering of the MBE producer strain coupled this system to long-chain-alcohol biosynthetic pathways resulting in de novo production of branched wax esters following addition of only propionate. PMID:24831705

  14. Chemical stability and in vitro and clinical efficacy of a novel hybrid retinoid derivative, bis-retinamido methylpentane.

    PubMed

    Kim, Ki Hyun; Lim, Dae Gon; Lim, Jun Yeul; Kim, Nam Ah; Park, So-Hyun; Cho, Jin Hun; Shin, Beom Soo; Jeong, Seong Hoon

    2015-11-10

    The anti-aging agent, retinol, has fewer side effects and similar biological activity compared to retinoic acid. However, retinol becomes unstable when exposed to light and heat. A novel hybrid retinoid derivative, bis-retinamido methylpentane (RS-2A), was newly developed to overcome the limitations. This study evaluated the chemical stability of RS-2A under thermal and light conditions by examining degradation profiles, and assessed the in vitro biological activity, cytotoxicity, and clinical efficacy. Chemical stability and degradation profiles were investigated with HPLC and LC-MS. Especially, photo-stability of RS-2A was analyzed under various conditions, such as change of physical state and concentration, different solvents, and various excipients. For analyses of cellular activity and cytotoxicity, human dermal fibroblasts were cultured with RS-2A. To evaluate the safety and efficacy of the compound with the cellular results, RS-2A was applied to women who had moderate to severe wrinkles at the periorbital region. All of the experiments were conducted with retinol as a reference. RS-2A was more stable than retinol to thermal conditions, especially in solution. Both RS-2A and retinol were unstable to light, but RS-2A showed enhanced photo-stability with regard to concentration, more polar solvent, and addition of proper excipients. RS-2A exhibited decreased cytotoxicity and enhanced effects on collagen synthesis compared with retinol. In a clinical study, a 4-week treatment with RS-2A significantly improved the appearance of periorbital wrinkles without any side effects. The results indicate that RS-2A might have potential as an anti-aging agent for cosmeceutical preparations because of its enhanced chemical stability, biological activity, safety, and clinical efficacy. PMID:26325317

  15. 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

  16. Cloned calves derived from somatic cell nuclear transfer embryos cultured in chemically defined medium or modified synthetic oviduct fluid

    PubMed Central

    Hong, So Gun

    2011-01-01

    Somatic cell nuclear transfer (SCNT) is considered to be a critical tool for propagating valuable animals. To determine the productivity calves resulting from embryos derived with different culture media, enucleated oocytes matured in vitro were reconstructed with fetal fibroblasts, fused, and activated. The cloned embryos were cultured in modified synthetic oviduct fluid (mSOF) or a chemically defined medium (CDM) and developmental competence was monitored. After 7 days of culturing, the blastocysts were transferred into the uterine horn of estrus-synchronized recipients. SCNT embryos that were cultured in mSOF or CDM developed to the blastocysts stages at similar rates (26.6% vs. 22.5%, respectively). A total of 67 preimplantational stage embryos were transferred into 34 recipients and six cloned calves were born by caesarean section, or assisted or natural delivery. Survival of transferred blastocysts to live cloned calves in the mSOF and the CDM was 18.5% (to recipients), 9.6% (to blastocysts) and 42.9% (to recipients), 20.0% (to blastocysts), respectively. DNA analysis showed that all cloned calves were genetically identical to the donor cells. These results demonstrate that SCNT embryos cultured in CDM showed higher viability as judged by survival of the calves that came to term compared to blastocysts derived from mSOF cultures. PMID:21368567

  17. 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

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

    PubMed

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

    2014-05-01

    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

  19. Roles of Chemical Complexity and Evolutionary Theory in Some Hepatic and Intestinal Enzymatic Systems in Chemical Reproducibility and Clinical Efficiency of Herbal Derivatives

    PubMed Central

    2014-01-01

    Despite the great marketing success, most physicians attribute poor efficacy to herbals. This perception is due to two situations that are an integral part of the herbal topic. The first is the poor phytochemical reproducibility obtained during the production process of herbal extracts, as herbal extracts are not always standardized in the whole manufacturing process, but only in their titer. The second problem is linked to the evolution of important enzymatic systems: cytochromes and ABC proteins. They are both enzyme classes with detoxifying properties and seem to have evolved from the molecular mould provided by active plant substances. During the evolution, as still happens today, polyphenols, saponins, terpenes, and alkaloids were ingested together with food. They do not possess any nutritional value but seem to be provided with a potential pharmacological activity. Cytochromes and ABC proteins, which evolved over time to detoxify food from vegetable chemical “actives,” now seem to limit the action of herbal derivatives. The comprehension of these 2 events may explain the origin of the widespread scepticism of physicians about herbal medicine and suggests that, after correct herbal standardization, use of antagonists of cytochromes and ABC systems will make it possible to recover their pharmacological potential. PMID:24977222

  20. An investigation of the thermal degradation mechanisms of a waste tire through chemical analysis including hydrocarbons, benzene derivatives, and Polycyclic

    E-print Network

    Columbia University

    including hydrocarbons, benzene derivatives, and Polycyclic Aromatic Hydrocarbons (PAHs) at high temperature a GC/MS. Significant Volatile Organic Carbons (VOCs) including benzene derivatives, PAHs, and Hetero

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

    SciTech Connect

    Schoeters, Elke . E-mail: elke.schoeters@vito.be; Nuijten, Jean-Marie; Heuvel, Rosette L. van den; Nelissen, Inge; Witters, Hilda; Schoeters, Greet E.R.; Tendeloo, Vigor F.I. van; Berneman, Zwi N.; Verheyen, Geert R.

    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.

  2. Substituent effect study on experimental ¹³C NMR chemical shifts of (3-(substituted phenyl)-cis-4,5-dihydroisoxazole-4,5-diyl)bis(methylene)diacetate derivatives.

    PubMed

    Kara, Yesim S

    2015-12-01

    Eleven novel (3-(substituted phenyl)-cis-4,5-dihydroisoxazole-4,5-diyl)bis(methylene) diacetate derivatives were synthesized in the present study. These dihydroisoxazole derivatives were characterized by IR, (1)H NMR, (13)C NMR and elemental analyses. Their (13)C NMR spectra were measured in Deuterochloroform (CDCl3). The correlation analysis for the substituent-induced chemical shift (SCS) with Hammett substituent constant (?), inductive substituent constant (?I), different of resonance substituent constants (?R, ?R(o)) and Swain-Lupton substituent parameters (F, R) were performed using SSP (single substituent parameter), and DSP (dual substituent parameter) methods, as well as single and multiple regression analysis. From the result of regression analysis, the effect of substituent on the (13)C NMR chemical shifts was explained. PMID:26172459

  3. 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

  4. Organic reactions for the electrochemical and photochemical production of chemical fuels from CO2 - The reduction chemistry of carboxylic acids and derivatives as bent CO2 surrogates.

    PubMed

    Luca, Oana R; Fenwick, Aidan Q

    2015-11-01

    The present review covers organic transformations involved in the reduction of CO2 to chemical fuels. In particular, we focus on reactions of CO2 with organic molecules to yield carboxylic acid derivatives as a first step in CO2 reduction reaction sequences. These biomimetic initial steps create opportunities for tandem electrochemical/chemical reductions. We draw parallels between long-standing knowledge of CO2 reactivity from organic chemistry, organocatalysis, surface science and electrocatalysis. We point out some possible non-faradaic chemical reactions that may contribute to product distributions in the production of solar fuels from CO2. These reactions may be accelerated by thermal effects such as resistive heating and illumination. PMID:26022364

  5. THE JOURNAL OF CHEMICAL PHYSICS 142, 064109 (2015) Analytic derivative couplings in time-dependent density functional theory

    E-print Network

    Herbert, John

    2015-01-01

    dynamics methods can be applied to go beyond the Born-Oppenheimer approximation and describe these non by the first-order nonadiabatic coupling matrix elements (deriv- ative couplings). Derivative couplings implementation of TDDFT is the version based on linear response (LR) of the electron density or density matrix

  6. Minocycline and doxycycline, but not other tetracycline-derived compounds, protect liver cells from chemical hypoxia and ischemia/reperfusion injury by inhibition of the mitochondrial calcium uniporter

    SciTech Connect

    Schwartz, Justin; Holmuhamedov, Ekhson; Zhang, Xun; Lovelace, Gregory L.; Smith, Charles D.; Lemasters, John J.

    2013-11-15

    Minocycline, a tetracycline-derived compound, mitigates damage caused by ischemia/reperfusion (I/R) injury. Here, 19 tetracycline-derived compounds were screened in comparison to minocycline for their ability to protect hepatocytes against damage from chemical hypoxia and I/R injury. Cultured rat hepatocytes were incubated with 50 ?M of each tetracycline-derived compound 20 min prior to exposure to 500 ?M iodoacetic acid plus 1 mM KCN (chemical hypoxia). In other experiments, hepatocytes were incubated in anoxic Krebs–Ringer–HEPES buffer at pH 6.2 for 4 h prior to reoxygenation at pH 7.4 (simulated I/R). Tetracycline-derived compounds were added 20 min prior to reperfusion. Ca{sup 2+} uptake was measured in isolated rat liver mitochondria incubated with Fluo-5N. Cell killing after 120 min of chemical hypoxia measured by propidium iodide (PI) fluorometry was 87%, which decreased to 28% and 42% with minocycline and doxycycline, respectively. After I/R, cell killing at 120 min decreased from 79% with vehicle to 43% and 49% with minocycline and doxycycline. No other tested compound decreased killing. Minocycline and doxycycline also inhibited mitochondrial Ca{sup 2+} uptake and suppressed the Ca{sup 2+}-induced mitochondrial permeability transition (MPT), the penultimate cause of cell death in reperfusion injury. Ru360, a specific inhibitor of the mitochondrial calcium uniporter (MCU), also decreased cell killing after hypoxia and I/R and blocked mitochondrial Ca{sup 2+} uptake and the MPT. Other proposed mechanisms, including mitochondrial depolarization and matrix metalloprotease inhibition, could not account for cytoprotection. Taken together, these results indicate that minocycline and doxycycline are cytoprotective by way of inhibition of MCU. - Highlights: • Minocycline and doxycycline are the only cytoprotective tetracyclines of those tested • Cytoprotective tetracyclines inhibit the MPT and mitochondrial calcium and iron uptake. • Cytoprotective tetracyclines protect by inhibiting the MCU.

  7. On the toxic effects of tetraethyl lead and its derivatives on the chrysophyte Poterioochromonas malhamensis. III. Chemical analysis

    SciTech Connect

    Roderer, G.

    1981-01-01

    The photolytic decomposition of tetraethyl lead (TEL) into the derivatives triethyl lead (TriEL), diethyl lead (DiEL), and into inorganic lead in an aqueous environment was examined by using a single-step dithizone extraction method. The results of the experiments conclusively indicated that TriEL is the toxic derivative of TEL which is created upon illumination and causes severe inhibitory effects in cultures of Poterioochromonas malhamensis poisoned by TEL. The significance of these findings for polluted natural environments and for the metabolic pathway of organolead in intoxicated mammalia is discussed briefly, and a diagrammatical model is presented describing the presumed fate of TEL and its derivatives under experimental conditions. (JMT)

  8. Total synthesis approaches to natural product derivatives based on the combination of chemical synthesis and metabolic engineering.

    PubMed

    Kirschning, Andreas; Taft, Florian; Knobloch, Tobias

    2007-10-21

    Secondary metabolites are an extremely diverse and important group of natural products with industrial and biomedical implications. Advances in metabolic engineering of both native and heterologous secondary metabolite producing organisms have allowed the directed synthesis of desired novel products by exploiting their biosynthetic potentials. Metabolic engineering utilises knowledge of cellular metabolism to alter biosynthetic pathways. An important technique that combines chemical synthesis with metabolic engineering is mutasynthesis (mutational biosynthesis; MBS), which advanced from precursor-directed biosynthesis (PDB). Both techniques are based on the cellular uptake of modified biosynthetic intermediates and their incorporation into complex secondary metabolites. Mutasynthesis utilises genetically engineered organisms in conjunction with feeding of chemically modified intermediates. From a synthetic chemist's point of view the concept of mutasynthesis is highly attractive, as the method combines chemical expertise with Nature's synthetic machinery and thus can be exploited to rapidly create small libraries of secondary metabolites. However, in each case, the method has to be critically compared with semi- and total synthesis in terms of practicability and efficiency. Recent developments in metabolic engineering promise to further broaden the scope of outsourcing chemically demanding steps to biological systems. PMID:17912378

  9. Derivation of Tissue-specific Functional Gene Sets to Aid Transcriptomic Analysis of Chemical Impacts on the Teleost Reproductive Axis.

    EPA Science Inventory

    Oligonucleotide microarrays are a powerful tool for unsupervised analysis of chemical impacts on biological systems. However, the lack of well annotated biological pathways for many aquatic organisms, including fish, and the poor power of microarray-based analyses to detect diffe...

  10. Identification of Volatile/Semi-Volatile Products Derived from Chemical Remediation of cis-1,3-Dichloropropene by Thiosulfate

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  11. 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...

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

    SciTech Connect

    Lee, Yongwon; Buchanan, B.G.; Rosenkranz, H.S.

    1996-10-01

    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. 7 refs., 5 tabs.

  13. 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 ...

  14. 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.

  15. Establishment of an advanced chemically defined medium for early embryos derived from in vitro matured and fertilized bovine oocytes.

    PubMed

    Momozawa, Kenji; Fukuda, Yoshinori

    2011-12-01

    A chemically defined medium would be useful for analyzing promoters or inhibitors in in vitro culture (IVC) of bovine embryos. However, an IVC system for bovine embryos in a chemically defined medium has not been fully established. The present study was carried out to establish an advanced chemically defined medium for bovine embryos that supports a high rate of embryo development to the blastocyst stage. In the first experiment, we examined the effects of addition of Medium RD (RPMI1640 and Dulbecco's MEM, 1:1 v/v) to mKSOM/aa on developmental competence. The addition of 10% RD to mKSOM/aa with BSA improved the rate of development to the blastocyst stage; however, 10% RD-mKSOM/aa with PVP, which is a chemically defined medium, caused a reduction in the percentage of hatching blastocysts. In the second experiment, embryos were cultured in the chemically defined medium of 10% RD-mKSOM/aa containing 11.7, 23.4, 46.8, 70.2 or 96.8 µM inositol. Inositol at the concentration of 70.2 µM improved the rate of development to the hatching blastocyst stage. In the third experiment, the optimal RD concentration in the IVC medium was evaluated. Embryos were cultured in the chemically defined medium supplemented with 10, 20 or 30% (v/v) RD. The rate of development to the blastocyst stage was highest with 20% RD. In the fourth experiment, the effects of N-acetylglucosamine (GlcNAc) as an IVC medium supplement on developmental competence were examined. The rate of development to the blastocyst stage with 1.0 mM GlcNAc was significantly higher than that without GlcNAc, but the rate of development with 1.2 mM GlcNAc was not different from that without GlcNAc. We also evaluated the ability of blastocysts produced in RD-mKSOM/aa to develop to normal calves after being transferred into recipients. Ten of the 16 recipients became pregnant, with 9 delivering normal calves. These results indicate that 20% RD-mKSOM/aa containing 70.2 µM myo-inositol and 1 mM GlcNAc is useful as a chemically defined medium for IVC of bovine embryos. PMID:21804301

  16. Shornephine A: Structure, Chemical Stability, and P-Glycoprotein Inhibitory Properties of a Rare Diketomorpholine from an Australian Marine-Derived Aspergillus sp.

    PubMed Central

    2015-01-01

    Chemical analysis of an Australian marine sediment-derived Aspergillus sp. (CMB-M081F) yielded the new diketomorpholine (DKM) shornephine A (1) together with two known and one new diketopiperazine (DKP), 15b-?-hydroxy-5-N-acetyladreemin (2), 5-N-acetyladreemin (3), and 15b-?-methoxy-5-N-acetyladreemin (4), respectively. Structure elucidation of 1–4 was achieved by detailed spectroscopic analysis, supported by chemical degradation and derivatization, and biosynthetic considerations. The DKM (1) underwent a facile (auto) acid-mediated methanolysis to yield seco-shornephine A methyl ester (1a). Our mechanistic explanation of this transformation prompted us to demonstrate that the acid-labile and solvolytically unstable DKM scaffold can be stabilized by N-alkylation. Furthermore, we demonstrate that at 20 ?M shornephine A (1) is a noncytotoxic inhibitor of P-glycoprotein-mediated drug efflux in multidrug-resistant human colon cancer cells. PMID:25158286

  17. Shornephine A: structure, chemical stability, and P-glycoprotein inhibitory properties of a rare diketomorpholine from an Australian marine-derived Aspergillus sp.

    PubMed

    Khalil, Zeinab G; Huang, Xiao-cong; Raju, Ritesh; Piggott, Andrew M; Capon, Robert J

    2014-09-19

    Chemical analysis of an Australian marine sediment-derived Aspergillus sp. (CMB-M081F) yielded the new diketomorpholine (DKM) shornephine A (1) together with two known and one new diketopiperazine (DKP), 15b-?-hydroxy-5-N-acetyladreemin (2), 5-N-acetyladreemin (3), and 15b-?-methoxy-5-N-acetyladreemin (4), respectively. Structure elucidation of 1-4 was achieved by detailed spectroscopic analysis, supported by chemical degradation and derivatization, and biosynthetic considerations. The DKM (1) underwent a facile (auto) acid-mediated methanolysis to yield seco-shornephine A methyl ester (1a). Our mechanistic explanation of this transformation prompted us to demonstrate that the acid-labile and solvolytically unstable DKM scaffold can be stabilized by N-alkylation. Furthermore, we demonstrate that at 20 ?M shornephine A (1) is a noncytotoxic inhibitor of P-glycoprotein-mediated drug efflux in multidrug-resistant human colon cancer cells. PMID:25158286

  18. Chemical insight from density functional modeling of molecular adsorption: Tracking the bonding and diffusion of anthracene derivatives on Cu(111) with molecular orbitals.

    PubMed

    Wyrick, Jonathan; Einstein, T L; Bartels, Ludwig

    2015-03-14

    We present a method of analyzing the results of density functional modeling of molecular adsorption in terms of an analogue of molecular orbitals. This approach permits intuitive chemical insight into the adsorption process. Applied to a set of anthracene derivates (anthracene, 9,10-anthraquinone, 9,10-dithioanthracene, and 9,10-diselenonanthracene), we follow the electronic states of the molecules that are involved in the bonding process and correlate them to both the molecular adsorption geometry and the species' diffusive behavior. We additionally provide computational code to easily repeat this analysis on any system. PMID:25770496

  19. 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

  20. Chemical insight from density functional modeling of molecular adsorption: Tracking the bonding and diffusion of anthracene derivatives on Cu(111) with molecular orbitals

    SciTech Connect

    Wyrick, Jonathan; Bartels, Ludwig; Einstein, T. L.

    2015-03-14

    We present a method of analyzing the results of density functional modeling of molecular adsorption in terms of an analogue of molecular orbitals. This approach permits intuitive chemical insight into the adsorption process. Applied to a set of anthracene derivates (anthracene, 9,10-anthraquinone, 9,10-dithioanthracene, and 9,10-diselenonanthracene), we follow the electronic states of the molecules that are involved in the bonding process and correlate them to both the molecular adsorption geometry and the species’ diffusive behavior. We additionally provide computational code to easily repeat this analysis on any system.

  1. The Redox Chemistry and Chemical Biology of H2S, Hydropersulfides and Derived Species: Implications to Their Possible Biological Activity and Utility

    PubMed Central

    Ono, Katsuhiko; Akaike, Takaake; Sawa, Tomohiro; Kumagai, Yoshito; Wink, David A.; Tantillo, Dean J.; Hobbs, Adrian J.; Nagy, Peter; Xian, Ming; Lin, Joseph; Fukuto, Jon M.

    2014-01-01

    Hydrogen sulfide (H2S) is an endogenously generated and putative signaling/effector molecule. In spite of its numerous reported functions, the chemistry by which it elicits its functions is not understood. Moreover, recent studies allude to the existence of other sulfur species besides H2S that may play critical physiological roles. Herein, the basic chemical biology of H2S as well as other related or derived species is discussed and reviewed. A particular focus of this review are the per- and poly-sulfides which are likely in equilibrium with free H2S and which may be important biological effectors themselves. PMID:25229186

  2. Chemical insight from density functional modeling of molecular adsorption: Tracking the bonding and diffusion of anthracene derivatives on Cu(111) with molecular orbitals

    NASA Astrophysics Data System (ADS)

    Wyrick, Jonathan; Einstein, T. L.; Bartels, Ludwig

    2015-03-01

    We present a method of analyzing the results of density functional modeling of molecular adsorption in terms of an analogue of molecular orbitals. This approach permits intuitive chemical insight into the adsorption process. Applied to a set of anthracene derivates (anthracene, 9,10-anthraquinone, 9,10-dithioanthracene, and 9,10-diselenonanthracene), we follow the electronic states of the molecules that are involved in the bonding process and correlate them to both the molecular adsorption geometry and the species' diffusive behavior. We additionally provide computational code to easily repeat this analysis on any system.

  3. Disruption of rosetting in Plasmodium falciparum malaria with chemically modified heparin and low molecular weight derivatives possessing reduced anticoagulant and other serine protease inhibition activities.

    PubMed

    Skidmore, Mark A; Dumax-Vorzet, Audrey F; Guimond, Scott E; Rudd, Timothy R; Edwards, Elizabeth A; Turnbull, Jeremy E; Craig, Alister G; Yates, Edwin A

    2008-03-13

    Severe malaria has been, in part, associated with the ability of parasite infected red blood cells to aggregate together with uninfected erythrocytes to form rosettes via the parasite protein PfEMP-1. In this study, inhibitors of rosetting by the Plasmodium falciparum strain R-29, based on chemically modified heparin polysaccharides (IC 50 = 1.97 x 10 (-2) and 3.05 x 10 (-3) mg.mL (-1)) and their depolymerized, low molecular weight derivatives were identified with reduced anticoagulant and protease (renin, pepsin, and cathepsin-D) activities. Low molecular weight derivatives of the two most effective inhibitors were shown to have distinct minimum size and strain-specific structural requirements for rosette disruption. These also formed distinct complexes in solution when bound to platelet-factor IV. PMID:18260612

  4. Human Induced Pluripotent Stem Cell Derived Neuronal Cells Cultured on Chemically-Defined Hydrogels for Sensitive In Vitro Detection of Botulinum Neurotoxin.

    PubMed

    Pellett, Sabine; Schwartz, Michael P; Tepp, William H; Josephson, Richard; Scherf, Jacob M; Pier, Christina L; Thomson, James A; Murphy, William L; Johnson, Eric A

    2015-01-01

    Botulinum neurotoxin (BoNT) detection provides a useful model for validating cell-based neurotoxicity screening approaches, as sensitivity is dependent on functionally competent neurons and clear quantitative endpoints are available for correlating results to approved animal testing protocols. Here, human induced pluripotent stem cell (iPSC)-derived neuronal cells were cultured on chemically-defined poly(ethylene glycol) (PEG) hydrogels formed by "thiol-ene" photopolymerization and tested as a cell-based neurotoxicity assay by determining sensitivity to active BoNT/A1. BoNT/A1 sensitivity was comparable to the approved in vivo mouse bioassay for human iPSC-derived neurons and neural stem cells (iPSC-NSCs) cultured on PEG hydrogels or treated tissue culture polystyrene (TCP) surfaces. However, maximum sensitivity for BoNT detection was achieved two weeks earlier for iPSC-NSCs that were differentiated and matured on PEG hydrogels compared to TCP. Therefore, chemically-defined synthetic hydrogels offer benefits over standard platforms when optimizing culture conditions for cell-based screening and achieve sensitivities comparable to an approved animal testing protocol. PMID:26411797

  5. Human Induced Pluripotent Stem Cell Derived Neuronal Cells Cultured on Chemically-Defined Hydrogels for Sensitive In Vitro Detection of Botulinum Neurotoxin

    PubMed Central

    Pellett, Sabine; Schwartz, Michael P.; Tepp, William H.; Josephson, Richard; Scherf, Jacob M.; Pier, Christina L.; Thomson, James A.; Murphy, William L.; Johnson, Eric A.

    2015-01-01

    Botulinum neurotoxin (BoNT) detection provides a useful model for validating cell-based neurotoxicity screening approaches, as sensitivity is dependent on functionally competent neurons and clear quantitative endpoints are available for correlating results to approved animal testing protocols. Here, human induced pluripotent stem cell (iPSC)-derived neuronal cells were cultured on chemically-defined poly(ethylene glycol) (PEG) hydrogels formed by “thiol-ene” photopolymerization and tested as a cell-based neurotoxicity assay by determining sensitivity to active BoNT/A1. BoNT/A1 sensitivity was comparable to the approved in vivo mouse bioassay for human iPSC-derived neurons and neural stem cells (iPSC-NSCs) cultured on PEG hydrogels or treated tissue culture polystyrene (TCP) surfaces. However, maximum sensitivity for BoNT detection was achieved two weeks earlier for iPSC-NSCs that were differentiated and matured on PEG hydrogels compared to TCP. Therefore, chemically-defined synthetic hydrogels offer benefits over standard platforms when optimizing culture conditions for cell-based screening and achieve sensitivities comparable to an approved animal testing protocol. PMID:26411797

  6. 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

  7. Composite bound states and broken U(1) symmetry in the chemical-master-equation derivation of the Gray-Scott model

    NASA Astrophysics Data System (ADS)

    Cooper, Fred; Ghoshal, Gourab; Pérez-Mercader, Juan

    2013-10-01

    We give a first principles derivation of the stochastic partial differential equations that describe the chemical reactions of the Gray-Scott model (GS): U+2V??3V and V??P, U??Q, with a constant feed rate for U. We find that the conservation of probability ensured by the chemical master equation leads to a modification of the usual differential equations for the GS model, which now involves two composite fields and also intrinsic noise terms. One of the composites is ?1=?v2, where ?=v is the concentration of the species V and the averaging is over the internal noise ?u,v,?1. The second composite field is the product of three fields ?=??u?v2 and requires a noise source to ensure probability conservation. A third composite ?2=?u?v can also be identified from the noise-induced reactions. The Hamiltonian that governs the time evolution of the many-body wave function, associated with the master equation, has a broken U(1) symmetry related to particle number conservation. By expanding around the (broken symmetry) zero-energy solution of the Hamiltonian (by performing a Doi shift) one obtains from our path integral formulation the usual reaction diffusion equation, at the classical level. The Langevin equations that are derived from the chemical master equation have multiplicative noise sources for the density fields ?u,?v,? that induce higher-order processes such as n?n scattering for n>3. The amplitude of the noise acting on ?v is itself stochastic in nature.

  8. Quantum-chemical calculations of the electronic structure of 2-amino-1,3-dicyano-5,6,7,8-tetrahydronaphthalene derivatives.

    PubMed

    Józefowicz, M; Bajorek, A; Pietrzak, M; Heldt, J R

    2013-09-01

    The UV-Visible absorption spectra of six, newly synthesized donor-substituted 2-amino-1,3-dicyano-5,6,7,8-tetrahydronaphthalene have been measured in methylcyclohexane (MCH) and assigned with the help of quantum-chemical calculations. Our calculations have been performed to assess information regarding the electronic state energy values, corresponding oscillator strengths, x-, y-, z-components of the transition dipole moments and molecular orbitals involved in the main electronic transitions of the studied compounds. Additionally, the experimental absorption transition dipole moments were calculated, on the basis of spectroscopic data, and compared with results of our quantum-chemical calculations. On the basis of the experimental results and quantum-chemical calculations, it was shown that the long-wavelength absorption band involves an overlap of three electronic transitions of different character. For all studied donor-acceptor (D-A) compounds in vapour-phase, the long-wavelength transition (S0?S1) does not possess charge transfer character, whereas the S0?S2 transition possesses electron transfer character e.g., ?-electrons of the acceptor moiety are moved to the donor part. Moreover, it is found that the electronic structure of the studied biphenyl derivatives can be approximately described within composite-model of decoupled moieties: donor and acceptor. PMID:23719413

  9. Optical Fiber Chemical Sensor with Sol-Gel Derived Refractive Material as Transducer for High Temperature Gas Sensing in Clean Coal Technology

    SciTech Connect

    Shiquan Tao

    2006-12-31

    The chemistry of sol-gel derived silica and refractive metal oxide has been systematically studied. Sol-gel processes have been developed for preparing porous silica and semiconductor metal oxide materials. Micelle/reversed micelle techniques have been developed for preparing nanometer sized semiconductor metal oxides and noble metal particles. Techniques for doping metal ions, metal oxides and nanosized metal particles into porous sol-gel material have also been developed. Optical properties of sol-gel derived materials in ambient and high temperature gases have been studied by using fiber optic spectroscopic techniques, such as fiber optic ultraviolet/visible absorption spectrometry, fiber optic near infrared absorption spectrometry and fiber optic fluorescence spectrometry. Fiber optic spectrometric techniques have been developed for investigating the optical properties of these sol-gel derived materials prepared as porous optical fibers or as coatings on the surface of silica optical fibers. Optical and electron microscopic techniques have been used to observe the microstructure, such as pore size, pore shape, sensing agent distribution, of sol-gel derived material, as well as the size and morphology of nanometer metal particle doped in sol-gel derived porous silica, the nature of coating of sol-gel derived materials on silica optical fiber surface. In addition, the chemical reactions of metal ion, nanostructured semiconductor metal oxides and nanometer sized metal particles with gas components at room temperature and high temperatures have also been investigated with fiber optic spectrometric methods. Three classes of fiber optic sensors have been developed based on the thorough investigation of sol-gel chemistry and sol-gel derived materials. The first group of fiber optic sensors uses porous silica optical fibers doped with metal ions or metal oxide as transducers for sensing trace NH{sub 3} and H{sub 2}S in high temperature gas samples. The second group of fiber optic sensors uses sol-gel derived porous silica materials doped with nanometer particles of noble metals in the form of fiber or coating for sensing trace H{sub 2}, NH{sub 3} and HCl in gas samples at for applications ambient temperature. The third classes of fiber optic sensors use sol-gel derived semiconductor metal oxide coating on the surface of silica optical fiber as transducers for selectively sensing H{sub 2}, CH{sub 4} and CO at high temperature. In addition, optical fiber temperature sensors use the fluorescence signal of rare-earth metal ions doped porous silica optical fiber or the optical absorption signal of thermochromic metal oxide materials coated on the surface of silica optical fibers have also been developed for monitoring gas temperature of corrosive gas. Based on the results obtained from this project, the principle of fiber optic sensor techniques for monitoring matrix gas components as well as trace components of coal gasification derived syngas has been established. Prototype sensors for sensing trace ammonia and hydrogen sulfide in gasification derived syngas have been built up in our laboratory and have been tested using gas samples with matrix gas composition similar to that of gasification derived fuel gas. Test results illustrated the feasibility of these sensors for applications in IGCC processes.

  10. Coumarins from the Herb Cnidium monnieri and chemically modified derivatives as antifoulants against Balanus albicostatus and Bugula neritina larvae.

    PubMed

    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 EC(50) 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 EC(50) 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

  11. Chemical interaction of atmospheric mineral dust-derived nanoparticles with natural seawater--EPS and sunlight-mediated changes.

    PubMed

    Kadar, Enikö; Cunliffe, Michael; Fisher, Andrew; Stolpe, Björn; Lead, Jamie; Shi, Zongbo

    2014-01-15

    Laboratory studies were conducted to investigate the interactions of nanoparticles (NPs) formed via simulated cloud processing of mineral dust with seawater under environmentally relevant conditions. The effect of sunlight and the presence of exopolymeric substances (EPS) were assessed on the: (1) colloidal stability of the nanoparticle aggregates (i.e. size distribution, zeta potential, polydispersity); (2) micromorphology and (3) Fe dissolution from particles. We have demonstrated that: (i) synthetic nano-ferrihydrite has distinct aggregation behaviour from NPs formed from mineral dusts in that the average hydrodynamic diameter remained unaltered upon dispersion in seawater (~1500 nm), whilst all dust derived NPs increased about three fold in aggregate size; (ii) relatively stable and monodisperse aggregates of NPs formed during simulated cloud processing of mineral dust become more polydisperse and unstable in contact with seawater; (iii) EPS forms stable aggregates with both the ferrihydrite and the dust derived NPs whose hydrodynamic diameter remains unchanged in seawater over 24h; (iv) dissolved Fe concentration from NPs, measured here as <3 kDa filter-fraction, is consistently >30% higher in seawater in the presence of EPS and the effect is even more pronounced in the absence of light; (v) micromorphology of nanoparticles from mineral dusts closely resemble that of synthetic ferrihydrite in MQ water, but in seawater with EPS they form less compact aggregates, highly variable in size, possibly due to EPS-mediated steric and electrostatic interactions. The larger scale implications on real systems of the EPS solubilising effect on Fe and other metals with the additional enhancement of colloidal stability of the resulting aggregates are discussed. PMID:24035844

  12. Dislocation substructure of mantle-derived olivine as revealed by selective chemical etching and transmission electron microscopy

    USGS Publications Warehouse

    Kirby, S.H.; Wegner, M.W.

    1978-01-01

    Cleaved and mechanically polished surfaces of olivine from peridotite xenoliths from San Carlos, Arizona, were chemically etched using the techniques of Wegner and Christie (1974). Dislocation etch pits are produced on all surface orientations and they tend to be preferentially aligned along the traces of subgrain boundaries, which are approximately parallel to (100), (010), and (001). Shallow channels were also produced on (010) surfaces and represent dislocations near the surface that are etched out along their lengths. The dislocation etch channel loops are often concentric, and emanate from (100) subgrain boundaries, which suggests that dislocation sources are in the boundaries. Data on subgrain misorientation and dislocation line orientation and arguments based on subgrain boundary energy minimization are used to characterize the dislocation structures of the subgrain boundaries. (010) subgrain boundaries are of the twist type, composed of networks of [100] and [001] screw dislocations. Both (100) and (001) subgrain boundaries are tilt walls composed of arrays of edge dislocation with Burgers vectors b=[100] and [001], respectively. The inferred slip systems are {001} ???100???, {100} ???001???, and {010} ???100??? in order of diminishing importance. Exploratory transmission electron microscopy is in accord with these identifications. The flow stresses associated with the development of the subgrain structure are estimated from the densities of free dislocations and from the subgrain dimensions. Inferred stresses range from 35 to 75 bars using the free dislocation densities and 20 to 100 bars using the subgrain sizes. ?? 1978 Springer-Verlag.

  13. Chemical Epigenetics Alters the Secondary Metabolite Composition of Guttate Excreted by an Atlantic-Forest-Soil-Derived Penicillium citreonigrum

    PubMed Central

    Wang, Xiaoru; Filho, José G. Sena; Hoover, Ashley R.; King, Jarrod B.; Ellis, Trevor K.; Powell, Douglas R.; Cichewicz, Robert H.

    2010-01-01

    Chemical epigenetic manipulation of Penicillium citreonigrum led to profound changes in the secondary metabolite profile of its guttate. While guttate from control cultures exhibited a relatively simple assemblage of secondary metabolites, the guttate collected from cultures treated with 50 ?M 5-azacytidine (a DNA methyltransferase inhibitor) were highly enriched in compounds representing at least three distinct biosynthetic families. The metabolites obtained from the fungus included six azaphilones (sclerotiorin (1), sclerotioramine (6), ochrephilone (2), dechloroisochromophilone III (3), dechloroisochromophilone IV (4), and 6-((3E,5E)-5,7-dimethyl-2-methylenenona-3,5-dienyl)-2,4-dihydroxy-3-methylbenzaldehyde (5)), pencolide (7), and two new meroterpenes (atlantinones A and B (9 and 10, respectively)). While pencolide was detected in the exudates of both control and 5-azacytidine-treated cultures, all of the other natural products were found exclusively in the guttates of the epigenetically modified fungus. All of the metabolites from the P. citreonigrum guttate were tested for antimicrobial activity in a disk diffusion assay. Both sclerotiorin and sclerotioramine caused modest inhibition of Staphylococcus epidermidis growth; however, only sclerotioramine was active against a panel of Candida strains. PMID:20450206

  14. Cytotoxicity of aflatoxin B1 and its chemically synthesised epoxide derivative on the A549 human epithelioid lung cell line.

    PubMed

    Palanee, T; Dutton, M F; Chuturgoon, A A

    2001-01-01

    Aflatoxin B1 (AFB1 ) is a carcinogenic mycotoxin found in feeds and in airborne grain dusts. Aflatoxin B1 requires biotransformation to the AFB1-8,9 epoxide (AFBO) by a bioactivation system and subsequent covalent binding to DNA or proteins, to exert its carcinogenic potential. The lung contains cytochrome P450, prostaglandin-H-synthase, lipoxygenase, epoxide hydrolase and other bioactivation enzymes, and is thus a potential target for the effects of AFB1 via the routes of inhalation and ingestion. The A549 human epithelioid lung cell line and the methylthiazol tetrazolium (MTT) bioassay were used to investigate the cytotoxicity of AFB1 and its chemically synthesised epoxide (AFBO) in vitro. Statistical analysis of the MTT results indicated that there were overall significant differences between the control and both the AFB1-treated (p < 0.0001) and AFBO-treated cells (p = 0.002). However, there was no significant difference between AFB1 and AFBO-treated cells, when the entire range of concentrations were assessed against each other (p = 0.2877). When analysed at each concentration, only at 0.01 mM was there a significant difference between the effects of AFB1 and AFBO (p = 0.0358). The results of this investigation show that AFB1 and AFBO are both cytotoxic in the A549 cell line. PMID:11678590

  15. Membranes as programmable matter: modulating physical-chemical behavior in lipid ensembles derived from archaea and eukaryotes

    NASA Astrophysics Data System (ADS)

    Gilmore, Sean Fitzpatrick

    Lipid membranes are of general interest to the scientific community due to their roles as cellular membranes, and because of their interesting material properties, such as tendencies to self-assemble into two- and three-dimensional structures. Further, there is interest in using lipid membranes as a self-assembling template or substrate for other materials, such as membrane proteins. The work presented here explores the physical-chemical interactions in and around artificial lipid membranes. In the first two chapters, lipid membranes are investigated as a form of programmable matter that responds to environmental changes. These responses manifest as two- and three-dimensional reorganization. In the subsequent chapters, the lipids of an extremophilic archaeon are examined in synthetic configurations to 1) identify how ensembles of lipids originating from organisms of different domains on the tree of life may behave in similar ways, and 2) to examine how the lipids of a desiccation-tolerant organism may be used to create robust lipid (bilayer) membranes that do not rely on liquid water to retain their structure. These collected findings expand how living membranes may be modulated or reorganized in vivo, and also suggest new ways to create programmable lipid-based materials.

  16. Influence of Stoichiometry on the Optical and Electrical Properties of Chemical Vapor Deposition Derived MoS2

    PubMed Central

    2015-01-01

    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

  17. Isolation and chemical identification of lipid derivatives from avocado (Persea americana) pulp with antiplatelet and antithrombotic activities.

    PubMed

    Rodriguez-Sanchez, Dariana Graciela; Flores-García, Mirthala; Silva-Platas, Christian; Rizzo, Sheryl; Torre-Amione, Guillermo; De la Peña-Diaz, Aurora; Hernández-Brenes, Carmen; García-Rivas, Gerardo

    2015-01-01

    Platelets play a pivotal role in physiological hemostasis. However, in coronary arteries damaged by atherosclerosis, enhanced platelet aggregation, with subsequent thrombus formation, is a precipitating factor in acute ischemic events. Avocado pulp (Persea americana) is a good source of bioactive compounds, and its inclusion in the diet as a source of fatty acid has been related to reduced platelet aggregability. Nevertheless, constituents of avocado pulp with antiplatelet activity remain unknown. The present study aims to characterize the chemical nature of avocado constituents with inhibitory effects on platelet aggregation. Centrifugal partition chromatography (CPC) was used as a fractionation and purification tool, guided by an in vitro adenosine diphosphate (ADP), arachidonic acid or collagen-platelet aggregation assay. Antiplatelet activity was initially linked to seven acetogenins that were further purified, and their dose-dependent effects in the presence of various agonists were contrasted. This process led to the identification of Persenone-C (3) as the most potent antiplatelet acetogenin (IC??=3.4 mM) among the evaluated compounds. In vivo evaluations with Persenone A (4) demonstrated potential protective effects against arterial thrombosis (25 mg kg?¹ of body weight), as coagulation times increased (2-fold with respect to the vehicle) and thrombus formation was attenuated (71% versus vehicle). From these results, avocado may be referred to as a functional food containing acetogenin compounds that inhibit platelet aggregation with a potential preventive effect on thrombus formation, such as those that occur in ischaemic diseases. PMID:25319210

  18. Tuning of intramolecular charge transfer properties and charge distributions in ferrocene-appended catechol derivatives by chemical substitution.

    PubMed

    Tahara, Keishiro; Akehi, Shogo; Akita, Tetsuhiro; Katao, Shohei; Kikuchi, Jun-Ichi; Tokunaga, Ken

    2015-09-01

    In this study, we report intramolecular charge transfer (ICT) properties and charge distributions in a series of FcC derivatives (FcC = 4-ferrocenylcatecholate where Fc = ferrocene and C = catecholate). This series consists of a previously reported complex FcV (4-ferrocenylveratrole) and newly synthesized complexes FcA (4-ferrocenylcatechol bis(acetate) and Pt((t)Bu2bpy)(FcC) ((t)Bu2bpy = 4,4'-di-tert-butyl-2,2'-dipyridyl). An electrochemical analysis of Pt((t)Bu2bpy)(FcC) using cyclic voltammetry revealed two well-defined, reversible waves which were assigned to the sequential oxidation of the Pt((t)Bu2bpy)(C) and Fc moieties. The potential splitting between the waves (524 mV) indicated that there was an electronic interaction between both moieties. ICT property and charge distribution of [Pt((t)Bu2bpy)(FcC)]?(+) were rationalized by comparison with the [FcV]?(+) and [FcA]?(+) (4-ferrocenylcatechol bis(acetate)). DFT calculations and UV-vis-NIR spectroscopy revealed that [Pt((t)Bu2bpy)(FcC)]?(+), [FcV]?(+), and [FcA]?(+) were ferrocenium (Fc(+))-centered rather than semiquinone ligand-centered and that these complexes exhibited ICT transition bands from the catechol-derivatized framework to the Fc(+) moiety in the near infrared (NIR) region. Both the electronic coupling parameter (HAB) and delocalization parameter (?) increased in value as the electron-donating strength of the substituent groups in the catechol-derivatized framework increased (OCOCH3 ([FcA]?(+)) < OCH3 ([FcV]?(+)) < O(-) ([Pt((t)Bu2bpy)(FcC)]?(+))). The electronic interactions between the organometallic center and the non-innocent framework were tuned by changing the substituents. The potential energy surfaces of the Fc(+) derivatives, obtained using two-state Marcus-Hush theory, can be modulated by changing the energy level of the molecular orbitals of the appended catechol-derivatized moieties. PMID:26212616

  19. Application studies of activated carbon derived from rice husks produced by chemical-thermal process--a review.

    PubMed

    Chen, Yue; Zhu, Yanchao; Wang, Zichen; Li, Ying; Wang, Lili; Ding, Lili; Gao, Xiaoyan; Ma, Yuejia; Guo, Yupeng

    2011-03-15

    The production of functional activated carbon materials starting from cheap natural precursors using environmentally friendly processes is a highly attractive subject in material chemistry today. Recently, much attention has been focused on the use of plant biomass to produce functional carbonaceous materials, encompassing economic, environmental and social issues. Besides the classical route to produce activated carbons from fossil materials, rice husk shows clear advantages in that it can generate a variety of cheap and sustainable carbonaceous materials with attractive nanostructure and functional patterns for a wide range of applications. From a comprehensive literature review, it was found that porous carbon that derived from rice husks, in addition to having wide availability, has fast kinetics and appreciable adsorption capacities too. Porous carbon materials also play a significant role in new applications such as catalytic supports, battery electrodes, capacitors, and gas storage. In this review, an extensive list of rice husks literature has been compiled. Conclusions have been drawn from the literature reviewed, and suggestions for future research are proposed. PMID:21353192

  20. Monitoring the chemical production of citrus-derived bioactive 5-demethylnobiletin using surface-enhanced Raman spectroscopy.

    PubMed

    Zheng, Jinkai; Fang, Xiang; Cao, Yong; Xiao, Hang; He, Lili

    2013-08-28

    To develop an accurate and convenient method for monitoring the production of citrus-derived bioactive 5-demethylnobiletin from the demethylation reaction of nobiletin, we compared surface-enhanced Raman spectroscopy (SERS) methods with a conventional high-performance liquid chromatography (HPLC) method. Our results show that both the substrate- and solution-based SERS methods correlated with the HPLC method very well. The solution method produced lower root-mean-square error of calibration and higher correlation coefficient than the substrate method. The solution method used an "affinity chromatography"-like procedure to separate the reactant nobiletin from the product 5-demthylnobiletin based on their different binding affinities to the silver dendrites. The substrate method was found simpler and faster to collect the SERS "fingerprint" spectra of the samples because no incubation between samples and silver was needed and only a trace amount of samples was required. Our results demonstrated that the SERS methods were superior to the HPLC method in conveniently and rapidly characterizing and quantifying 5-demethylnobiletin production. PMID:23885986

  1. Receptor-specific scoring functions derived from quantum chemical models improve affinity estimates for in-silico drug discovery.

    PubMed

    Fischer, Bernhard; Fukuzawa, Kaori; Wenzel, Wolfgang

    2008-03-01

    The adaptation of forcefield-based scoring function to specific receptors remains an important challenge for in-silico drug discovery. Here we compare binding energies of forcefield-based scoring functions with models that are reparameterized on the basis of large-scale quantum calculations of the receptor. We compute binding energies of eleven ligands to the human estrogen receptor subtype alpha (ERalpha) and four ligands to the human retinoic acid receptor of isotype gamma (RARgamma). Using the FlexScreen all-atom receptor-ligand docking approach, we compare docking simulations parameterized by quantum-mechanical calculation of a large protein fragment with purely forcefield-based models. The use of receptor flexibility in the FlexScreen permits the treatment of all ligands in the same receptor model. We find a high correlation between the classical binding energy obtained in the docking simulation and quantum mechanical binding energies and a good correlation with experimental affinities R=0.81 for ERalpha and R=0.95 for RARgamma using the quantum derived scoring functions. A significant part of this improvement is retained, when only the receptor is treated with quantum-based parameters, while the ligands are parameterized with a purely classical model. PMID:17876816

  2. Study of chemical reactivity in relation to experimental parameters of efficiency in coumarin derivatives for dye sensitized solar cells using DFT.

    PubMed

    Soto-Rojo, Rody; Baldenebro-López, Jesús; Glossman-Mitnik, Daniel

    2015-06-01

    A group of dyes derived from coumarin was studied, which consisted of nine molecules using a very similar manufacturing process of dye sensitized solar cells (DSSCs). Optimized geometries, energy levels of the highest occupied molecular orbital and the lowest unoccupied molecular orbital, and ultraviolet-visible spectra were obtained using theoretical calculations, and they were also compared with experimental conversion efficiencies of the DSSC. The representation of an excited state in terms of natural transition orbitals (NTOs) was studied. Chemical reactivity parameters were calculated and correlated with the experimental data linked to the efficiency of the DSSC. A new proposal was obtained to design new molecular systems and to predict their potential use as a dye in DSSCs. PMID:25959071

  3. Physico-chemical characteristics of coated silicone textured versus smooth breast implants differentially influence breast-derived fibroblast morphology and behaviour.

    PubMed

    Valencia-Lazcano, Anai A; Alonso-Rasgado, Teresa; Bayat, Ardeshir

    2014-12-01

    Capsule formation is an inevitable consequence of silicone breast implantation. Clinically challenging dense fibrocollagenous capsular contractures occur at different rates between smooth compared to textured surfaces. Host response is influenced by several factors including implant surface texture, chemistry and interactions between cells and the extracellular matrix (ECM). Specific coatings can modify the physico-chemical properties of implant surfaces eliciting specific cellular reactions. Therefore, we evaluated the physico-chemical characteristics of coated smooth versus textured silicone breast implants on breast-derived fibroblast morphology and behaviour using (a) confocal laser microscopy, (b) Raman spectroscopy and (c) the effect of four unique protein and glycosaminoglycan (GAG) coatings (aggrecan, collagen I, fibronectin and hyaluronic acid) on breast-derived fibroblast attachment, proliferation, morphology, spreading, cytotoxicity and gene expression. Collagen I, fibronectin and hyaluronic acid coatings exhibited satisfactory fibroblast adhesion (p<0.001) in comparison to uncoated surfaces. Cell adhesion was less on smooth surfaces compared to textured surfaces (p<0.001). Fibroblasts cultured on collagen I, fibronectin and hyaluronic acid coated implants demonstrated improved cell proliferation than uncoated surfaces (p<0.001). LDH assay showed that coating surfaces with collagen I, fibronectin and hyaluronic acid did not induce cytotoxicity. Alpha-actinin expression and fibroblast adhesion to the substrate were upregulated (p<0.001), in textured versus smooth surfaces. FAK, vinculin and paxillin expression were upregulated (p<0.001), in all surfaces coated with fibronectin and collagen I. In conclusion, we present original data for expression of adhesion-related genes, cell morphology and proliferation in breast fibroblasts following the application of specific coatings on breast implant surfaces. PMID:25238227

  4. 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.

  5. 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.

  6. 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

    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.

  7. 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

  8. Lead and copper immobilization in a shooting range soil using soybean stover- and pine needle-derived biochars: Chemical, microbial and spectroscopic assessments.

    PubMed

    Ahmad, Mahtab; Ok, Yong Sik; Rajapaksha, Anushka Upamali; Lim, Jung Eun; Kim, Byung-Yong; Ahn, Jae-Hyung; Lee, Young Han; Al-Wabel, Mohammad I; Lee, Sung-Eun; Lee, Sang Soo

    2016-01-15

    Biochar (BC) could be a potential candidate for the remediation of metal contaminated soil. Mechanistic understandings are needed for the appropriate selection of BC and investigating molecular microbial ecological interactions. The soybean stover-derived BCs were more effective in immobilizing Pb (88%) and Cu (87%) than the pine needle-derived BCs in a contaminated shooting range soil. The sequential chemical extractions indicated that BCs stimulated the geochemical transformation of metal species. Spectroscopic investigations using scanning electron microscopic elemental dot mapping and extended X-ray absorption fine structure spectroscopic measurements showed that Pb in the BCs amended soils was immobilized by the formation of stable chloropyromorphite. Soil organic C and microbial activity were also enhanced by BC. The non-labile C fraction in the soil amended with BCs produced at 700°C was increased. Biochars showed less impact on the bacterial community than feedstock biomass as promulgated by the pyrosequencing of 16S rRNA gene. The feedstock type (namely soybean stover and pine needles) was the main factor influencing the BCs efficacy on metals' (im) mobilization and bacterial health in soils. PMID:26355413

  9. Topoisomerase II DNA cleavage stimulation, DNA binding activity, cytotoxicity, and physico-chemical properties of 2-aza- and 2-aza-oxide-anthracenedione derivatives.

    PubMed

    De Isabella, P; Palumbo, M; Sissi, C; Capranico, G; Carenini, N; Menta, E; Oliva, A; Spinelli, S; Krapcho, A P; Giuliani, F C

    1995-07-01

    The cytotoxic activity of mitoxantrone and related anthracenediones has been ascribed to the ability of these compounds to interfere with DNA topoisomerase II function, resulting in DNA cleavage stimulation. The molecular details of enzyme inhibition by these intercalating agents remain to be defined. In an attempt to identify the structural determinants for optimal activity, the molecular and cellular effects of a series of heteroanalogues bearing different side-chains were examined in relation to the physico-chemical and DNA binding properties of these compounds. The results indicated that substitution of a pyridine ring for the dihydroxyphenylene ring in the planar chromophore caused a marked reduction of cytotoxic activity and of the ability to stimulate topoisomerase II-mediated DNA damage in intact cells and with simian virus 40 DNA in vitro. Although all tested derivatives were shown to intercalate into DNA, their DNA binding affinities were appreciably lower than that of mitoxantrone. The behavior of 2-aza derivatives more closely resembled that of ametantrone, suggesting that the potency of agents of this class is influenced more by the presence of hydroxyl groups than by the phenylene ring. The observation that a dramatic reduction (or loss) of the ability of aza derivatives to stimulate DNA cleavage is associated with a marked reduction of cytotoxic potency supports a primary role of topoisomerase II-mediated effects in the mechanism of action of the effective agents of this class. Because appreciable cytotoxic activity and significant in vivo antitumor efficacy are retained by compounds inactive (or poorly active) in inhibition of topoisomerase II, these results are consistent with multiple effects of anthracenediones at the cellular level. PMID:7623772

  10. The Chemically Synthesized Ageladine A-Derivative LysoGlow84 Stains Lysosomes in Viable Mammalian Brain Cells and Specific Structures in the Marine Flatworm Macrostomum lignano

    PubMed Central

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

    2015-01-01

    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

  11. Chemical activation in Rhinella arenarum oocytes: effect of dehydroleucodine (DhL) and its hydrogenated derivative (2H-DhL).

    PubMed

    Medina, M F; Bühler, M I; Sánchez-Toranzo, G

    2015-12-01

    Mature oocytes are arrested in metaphase II due to the presence of high levels of active maturation promoting factor (MPF). After fertilization, active MPF levels decline abruptly, enabling oocytes to complete meiosis II. One of the first and universal events of oocyte activation is an increase in cytosolic Ca2+ that would be responsible for MPF inactivation. Mature oocytes can also be activated by parthenogenetic activation. The aims of this work are to test the ability of dehydroleucodine (DhL) and its hydrogenated derivative 11,13-dihydro-dehydroleucodine (2H-DhL) to induce chemical activation in amphibian oocytes and to study the participation of calcium in the process. Results indicated that DhL and 2H-DhL induced oocyte activation in a dose-dependent manner. After 90 min of treatment, DhL 36 ?M was able to induce 95% activation, while 2H-DhL 36 ?M was less active, with only 40% activation. Our results suggest that DhL induced the inhibition of MPF activity, probably by an increase in intracellular Ca2+ concentration. Extracellular Ca2+ would not be significant, although Ca2+ release from intracellular stores is critical. In this sense, IP3Rs and RyRs were involved in the Ca2+ transient induced by lactones. In this species, RyRs appears to be the largest contributor to Ca2+ release in DhL-induced activation. Although more studies are needed on the mechanism of action through which these lactones induce oocyte activation in Rhinella arenarum, the results of this research provide interesting perspectives for the use of these lactones as chemical activators in in vitro fertilization and cloning. PMID:25424172

  12. Chemical Modification of a Dehydratase Enzyme Involved in Bacterial Virulence by an Ammonium Derivative: Evidence of its Active Site Covalent Adduct.

    PubMed

    González-Bello, Concepción; Tizón, Lorena; Lence, Emilio; Otero, José M; van Raaij, Mark J; Martinez-Guitian, Marta; Beceiro, Alejandro; Thompson, Paul; Hawkins, Alastair R

    2015-07-29

    The first example of an ammonium derivative that causes a specific modification of the active site of type I dehydroquinase (DHQ1), a dehydratase enzyme that is a promising target for antivirulence drug discovery, is described. The resolution at 1.35 Å of the crystal structure of DHQ1 from Salmonella typhi chemically modified by this ammonium derivative revealed that the ligand is covalently attached to the essential Lys170 through the formation of an amine. The detection by mass spectroscopy of the reaction intermediates, in conjunction with the results of molecular dynamics simulations, allowed us to explain the inhibition mechanism and the experimentally observed differences between S. typhi and Staphylococcus aureus enzymes. The results presented here reveal that the replacement of Phe225 in St-DHQ1 by Tyr214 in Sa-DHQ1 and its hydrogen bonding interaction with the conserved water molecule observed in several crystal structures protects the amino adduct against further dehydration/aromatization reactions. In contrast, for the St-DHQ1 enzyme, the carboxylate group of Asp114, with the assistance of this water molecule, would trigger the formation of a Schiff base that can undergo further dehydration reactions until full aromatization of the cyclohexane ring is achieved. Moreover, in vitro antivirulence studies showed that the reported compound is able to reduce the ability of Salmonella Enteritidis to kill A459 respiratory cells. These studies have identified a good scaffold for the design of irreversible inhibitors that can be used as drugs and has opened up new opportunities for the development of novel antivirulence agents by targeting the DHQ1 enzyme. PMID:26148116

  13. Effect of hydrogen sulfide on chemical looping combustion of coal-derived synthesis gas over bentonite-supported metal-oxide oxygen carriers

    SciTech Connect

    Tian, H.J.; Simonyi, T.; Poston, J.; Siriwardane, R.

    2009-09-15

    The effect of hydrogen sulfide (H{sub 2}S) on the chemical looping combustion of coal-derived synthesis gas with bentonite-supported metal oxides - such as iron oxide, nickel oxide, manganese oxide, and copper oxide - was investigated by thermogravimetric analysis, mass spectrometry, and X-ray photoelectron spectroscopy (XPS). During the reaction with synthesis gas containing H{sub 2}S, metal-oxide oxygen carriers were first reduced by carbon monoxide and hydrogen, and then interacted with H{sub 2}S to form metal sulfide, which resulted in a weight gain during the reduction/sulfidation step. The reduced/sulfurized compounds could be regenerated to form sulfur dioxide and oxides during the oxidation reaction with air. The reduction/oxidation capacities of iron oxide and nickel oxide were not affected by the presence of H{sub 2}S, but both manganese oxide and copper oxide showed decreased reduction/oxidation capacities. However, the rates of reduction and oxidation decreased in the presence of H{sub 2}S for all four metal oxides.

  14. Effect of hydrogen sulfide on chemical looping of coal-derived synthesis gas over bentonite-supported metal---oxide oxygen carriers

    SciTech Connect

    Tian, H.; Simonyi, T.; Poston, J.; Siriwardane, R.

    2009-01-01

    The effect of hydrogen sulfide (H2S) on the chemical looping combustion of coal-derived synthesis gas with bentonite-supported metal oxidesssuch as iron oxide, nickel oxide, manganese oxide, and copper oxideswas investigated by thermogravimetric analysis, mass spectrometry, and X-ray photoelectron spectroscopy (XPS). During the reaction with synthesis gas containing H2S, metal-oxide oxygen carriers were first reduced by carbon monoxide and hydrogen, and then interacted with H2S to form metal sulfide, which resulted in a weight gain during the reduction/sulfidation step. The reduced/sulfurized compounds could be regenerated to form sulfur dioxide and oxides during the oxidation reaction with air. The reduction/oxidation capacities of iron oxide and nickel oxide were not affected by the presence of H2S, but both manganese oxide and copper oxide showed decreased reduction/oxidation capacities. However, the rates of reduction and oxidation decreased in the presence of H2S for all four metal oxides.

  15. VITAL NMR: Using Chemical Shift Derived Secondary Structure Information for a Limited Set of Amino Acids to Assess Homology Model Accuracy

    SciTech Connect

    Brothers, Michael C; Nesbitt, Anna E; Hallock, Michael J; Rupasinghe, Sanjeewa; Tang, Ming; Harris, Jason B; Baudry, Jerome Y; Schuler, Mary A; Rienstra, Chad M

    2011-01-01

    Homology modeling is a powerful tool for predicting protein structures, whose success depends on obtaining a reasonable alignment between a given structural template and the protein sequence being analyzed. In order to leverage greater predictive power for proteins with few structural templates, we have developed a method to rank homology models based upon their compliance to secondary structure derived from experimental solid-state NMR (SSNMR) data. Such data is obtainable in a rapid manner by simple SSNMR experiments (e.g., (13)C-(13)C 2D correlation spectra). To test our homology model scoring procedure for various amino acid labeling schemes, we generated a library of 7,474 homology models for 22 protein targets culled from the TALOS+/SPARTA+ training set of protein structures. Using subsets of amino acids that are plausibly assigned by SSNMR, we discovered that pairs of the residues Val, Ile, Thr, Ala and Leu (VITAL) emulate an ideal dataset where all residues are site specifically assigned. Scoring the models with a predicted VITAL site-specific dataset and calculating secondary structure with the Chemical Shift Index resulted in a Pearson correlation coefficient (-0.75) commensurate to the control (-0.77), where secondary structure was scored site specifically for all amino acids (ALL 20) using STRIDE. This method promises to accelerate structure procurement by SSNMR for proteins with unknown folds through guiding the selection of remotely homologous protein templates and assessing model quality.

  16. Upgrading oxygenated Fischer-Tropsch derivatives and one-step direct synthesis of ethyl acetate from ethanol - examples of the desirability of research on simple chemical compounds transformations.

    PubMed

    Klimkiewicz, Roman

    2014-01-01

    Oxygenates formed as by-products of Fischer-Tropsch syntheses can be transformed into other Fischer-Tropsch derived oxygenates instead of treating them as unwanted chemicals. One-step direct synthesis of ethyl acetate from ethanol is feasible with the use of some heterogeneous catalysts. Despite their apparent simplicity, both transformations are discussed as targeted fields of research. Furthermore, the two concepts are justified due to the environmental protection. Arguments regarding the Fischer-Tropsch process are focused on the opportunities of the utilization of undesirable by-products. The effective striving for their utilization can make the oxygenates the targeted products of this process. Arguments regarding the one-step direct synthesis of ethyl acetate underline the environmental protection and sustainability as a less waste-generating method but, above all, highlight the possibility of reducing the glycerol overproduction problem. The production of ethyl acetate from bioethanol and then transesterification of fats and oils with the use of ethyl acetate allows managing all the renewable raw materials. Thus, the process enables the biosynthesis of biodiesel without glycerine by-product and potentially would result in the increase in the demand for ethyl acetate. Graphical Abstract. PMID:25648719

  17. 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. )

    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.

  18. Chemical microsensors

    SciTech Connect

    Li, DeQuan; Swanson, Basil I.

    1995-01-01

    An article of manufacture is provided including a substrate having an oxide surface layer and a selective thin film of a cyclodextrin derivative chemically bound upon said substrate, said film is adapted for the inclusion of a selected organic compound therewith. Such an article can be either a chemical sensor capable of detecting a resultant mass change from inclusion of the selected organic compound or a chemical separator capable of reversibly selectively separating a selected organic compound.

  19. Predicting biological effects of environmental mixtures using exposure:activity ratios (EAR) derived from US EPA’s ToxCast data: Retrospective application to chemical monitoring data

    EPA Science Inventory

    Chemical monitoring has been widely used in environmental surveillance to assess exposure to environmental contaminants which could represent potential hazards to exposed organisms. However, the ability to detect chemicals in the environment has rapidly outpaced assessment of pot...

  20. Chemical and genetic blockade of HDACs enhances osteogenic differentiation of human adipose tissue-derived stem cells by oppositely affecting osteogenic and adipogenic transcription factors

    SciTech Connect

    Maroni, Paola; Brini, Anna Teresa; Dipartimento di Scienze Biomediche, Chirurgiche ed Odontoiatriche, Universita degli Studi di Milano, Milano ; Arrigoni, Elena; Girolamo, Laura de; Niada, Stefania; Dipartimento di Scienze Biomediche, Chirurgiche ed Odontoiatriche, Universita degli Studi di Milano, Milano ; Matteucci, Emanuela; Bendinelli, Paola; Desiderio, Maria Alfonsina

    2012-11-16

    Highlights: Black-Right-Pointing-Pointer Acetylation affected hASCs osteodifferentiation through Runx2-PPAR{gamma}. Black-Right-Pointing-Pointer HDACs knocking-down favoured the commitment effect of osteogenic medium. Black-Right-Pointing-Pointer HDACs silencing early activated Runx2 and ALP. Black-Right-Pointing-Pointer PPAR{gamma} reduction and calcium/collagen deposition occurred later. Black-Right-Pointing-Pointer Runx2/PPAR{gamma} target genes were modulated in line with HDACs role in osteo-commitment. -- Abstract: The human adipose-tissue derived stem/stromal cells (hASCs) are an interesting source for bone-tissue engineering applications. Our aim was to clarify in hASCs the role of acetylation in the control of Runt-related transcription factor 2 (Runx2) and Peroxisome proliferator activated receptor (PPAR) {gamma}. These key osteogenic and adipogenic transcription factors are oppositely involved in osteo-differentiation. The hASCs, committed or not towards bone lineage with osteoinductive medium, were exposed to HDACs chemical blockade with Trichostatin A (TSA) or were genetically silenced for HDACs. Alkaline phosphatase (ALP) and collagen/calcium deposition, considered as early and late osteogenic markers, were evaluated concomitantly as index of osteo-differentiation. TSA pretreatment, useful experimental protocol to analyse pan-HDAC-chemical inhibition, and switch to osteogenic medium induced early-osteoblast maturation gene Runx2, while transiently decreased PPAR{gamma} and scarcely affected late-differentiation markers. Time-dependent effects were observed after knocking-down of HDAC1 and 3: Runx2 and ALP underwent early activation, followed by late-osteogenic markers increase and by PPAR{gamma}/ALP activity diminutions mostly after HDAC3 silencing. HDAC1 and 3 genetic blockade increased and decreased Runx2 and PPAR{gamma} target genes, respectively. Noteworthy, HDACs knocking-down favoured the commitment effect of osteogenic medium. Our results reveal a role for HDACs in orchestrating osteo-differentiation of hASCs at transcriptional level, and might provide new insights into the modulation of hASCs-based regenerative therapy.

  1. Recognizing subtle evidence for silicic magma derivation from petrochemically-similar arc crust: Isotopic and chemical evidence for the bimodal volcanic series of Gorely Volcanic Center, Kamchatka, Russia

    NASA Astrophysics Data System (ADS)

    Seligman, A. N.; Bindeman, I. N.; Ellis, B. S.; Ponomareva, V.; Leonov, V.

    2012-12-01

    The Kamchatka Peninsula is home to some of the most prolific subduction related volcanic activity in the world. Gorely caldera and its central volcano are located in the rear of its currently active Eastern Volcanic Front. Recent work determined the presence of explosive ignimbrite eruptions sourced from Gorely volcano during the Pleistocene. We studied 32 eruptive units, including tephrochronologically-dated Holocene tephra, stratigraphically-arranged ignimbrites, as well as pre- and post-caldera lavas. We analyzed oxygen isotope ratios of pyroxene and plagioclase grains by laser fluorination, and major and trace element compositions of whole rocks. In addition, we determined 87Sr/86Sr and 143Nd/144Nd ratios of caldera-forming ignimbrite eruptions. Chemical compositions show that Gorely eruptive units range from basalt to basaltic andesite in the "Pra-Gorely" stages prior to caldera formation and the modern Gorely stages forming its current edifice. In contrast, eruptive material from earlier ignimbrites exposed at Opasny Ravine consists primarily of dacite. Whole rock analyses for Gorely indicate that silicic rocks and ignimbrites volumetrically dominate all other products, forming separate bimodal peaks in our SiO2-frequency diagram. In addition, trace element concentrations and ratios define two trends, one for more silicic and another for more mafic material. ?18Omelt values range from a low of 4.85 up to 6.22‰, where the lowest value was found in the last caldera forming eruption, suggesting incorporation of hydrothermally-altered material from earlier eruptions. 87Sr/86Sr and 143Nd/144Nd ratios range from 0.70328 to 0.70351 and from 0.51303 to 0.51309 respectively, with higher and more diverse values being characteristic of earlier ignimbrite units; again suggesting incorporation of surrounding crustal material. In contrast to these results, MELTS modeling using a variety of likely primitive basalts from Gorely shows it is possible to obtain silicic chemical compositions near the evolved ignimbrite compositions, strictly through 70-80% fractional crystallization at 1-2 kbars and NNO oxygen fugacity. The combination of light ?18O values as well as elevated 87Sr/86Sr and low 143Nd/144Nd values, in addition to the volumetric excess of silicic rocks suggest assimilation of the older and petrochemically-similar country-rocks (Karymshina volcano and/or the underlying Akhomten Massif). This research can be utilized for studies of other volcanoes at "long-term centers", underscoring the importance of using both isotopes and modeling of fractional crystallization to determine silicic magma derivation through coupled shallow crustal assimilation of similar older material and fractional crystallization.

  2. The effect of alterations in physical and chemical characteristics on TOBEC-derived body composition estimates: validation with non-human models.

    PubMed

    De Bruin, N C; Luijendijk, I H; Visser, H K; Degenhart, H J

    1994-07-01

    The measurement of total-body electrical conductivity (TOBEC) has become one of the standard methods for the estimation of body composition in infants. We investigated, using non-human models, the effect on the accuracy of TOBEC-derived body composition estimates of alterations in physical and chemical characteristics of the fat-free mass (FFM). The effect of electrolyte type, concentration and volume on TOBEC was determined using 2, 3 and 51 solutions of six different chlorides and sodium bicarbonate. Equimolar concentrations yielded TOBEC values in accordance with known ion conductivities: H+ > Ca2+ > Mg2+ > K+ > Na+ > Li+ and Cl- > HCO3-. The behaviour of these solutions was described very accurately over a wide range of concentrations (1-200 mM) by a simple exponential law. Dissolved egg-white protein, glycine and L-glutamine elicited no TOBEC signal. In vitro, using polyethylene bottles filled with physiologic saline, in the interval of 2-45 degrees C a linear relation was observed between temperature and TOBEC. Below the freezing point no TOBEC signal was elicited. The effect of tissue autolysis and body temperature on TOBEC was examined by repeated measurements of TOBEC and temperature in seven fresh infant minipig cadavers. Five minipigs were allowed to cool. Shortly after death TOBEC decreased by 2.5% per degrees C. Two animals were kept at constant temperature. The TOBEC signal showed a gradual increase of 9% after 7 h due to autolysis. We conclude that in vivo TOBEC measurements are affected by ion concentration (e.g. non-isotonic hydration changes), geometry (e.g. deviations in body shape), temperature (e.g. fever, skin cooling) and tissue autolysis (measurements after death). Proteins, molecules with strong dipole moments and ions trapped in crystalline structures do not significantly affect the TOBEC reading. PMID:15552103

  3. Constraints on the Origins of Along-Arc and Cross-Arc Chemical Variations in Arc Volcanic systems Derived from Global Systematics of Fluid-Mobile Elements

    NASA Astrophysics Data System (ADS)

    Ryan, Jeffrey

    2014-05-01

    The fluid-mobile element (FME) "clan" (B, Cs, As, Sb; conditionally Pb, Rb, Ba, Li, N, I: Leeman 1996; Noll et al 1996; Bebout et al 1999; Savov et al 2005) comprises a chemically disparate suite of trace elements that have in common evidence for low T°/low P mobility from subducting materials in H2O-dominated fluid species. The FME are highly variable in volcanic arc lavas, showing marked along-arc and across arc changes in nearly all of the arc volcanic systems that have been examined. Globally, along-arc variability of the FME can be explained as source mixing, with most arcs defining arrays between two predominant sources: the first a strongly FME-enriched endmember, showing enrichment patterns consistent with those observed in subduction-related serpentinites (Savov et al 2005; Hattori and Guillot 2007), and the second an FME-poor source with signatures for other large-ion lithophile elements (LIL) consistent with subducted slab (predominantly subducted sediment) derivation. The mantle is a negligible contributor to FME systematics in those arcs where the inferred thermal structures are cool at relatively shallow (30-40 km) depths (e.g., Syracuse, et al 2011). However, in the relatively few arcs that show hotter thermal structures at shallow depths, the FME-enriched component is absent, and the mixing components are the mantle and the FME-poor, LIL enriched component observed in all arcs. Regular across-arc declines in enrichments of boron and other FME are a diagnostic feature in volcanic arcs globally. B abundance and isotope systematics for across-arc transects point to a) anomalously high B and B isotope signals near the volcanic front, often some of the highest signatures in the arc, suggesting locally higher inputs of the FME-enriched endmember to mantle sources at that point along the volcanic front. These enrichments, as well as the positioning of the widest volcanic cross-chains, are often linked to physical phenomena (seamount or fracture zone subduction, or faults or grabens perpendicular to the strike of the arc). b) Along cross-arc arrays, there is FME evidence for three-component mixing, involving the two slab-derived FME components and the mantle, in which the FME-depleted slab endmember plays a greater role as subduction depths increase. In general, the overriding arc crust plays a minor role in the FME systematics of arcs, though in those cases where the crustal section is thick and slab-derived signatures are modest, the crustal contribution helps define a baseline level for FME abundance and isotopic signatures throughout the arc. References: Bebout, et al 1999, EPSL 177, 69; Hattori and Guillot, 2007, GCubed, http://dx.doi.org/10.1029/2007GC001594; Leeman. 1996, AGU Monograph 96, 269; Noll et al, 1996, GCA 60, 587; Savov et al, 2005; GCubed, Q04J15 DOI10.1029/2004GC000777; Syracuse et al. 2011, GCubed, http://dx.doi.org/10.1029/2005GC001045.

  4. Adding liraglutide to the backbone therapy of biguanide in patients with coronary artery disease and newly diagnosed type-2 diabetes (the AddHope2 study): a randomised controlled study protocol

    PubMed Central

    Anholm, Christian; Kumarathurai, Preman; Klit, Malene S; Kristiansen, Ole P; Nielsen, Olav W; Ladelund, Steen; Madsbad, Sten; Sajadieh, Ahmad; Haugaard, Steen B

    2014-01-01

    Introduction Newly diagnosed type 2 diabetes mellitus (T2DM) in patients with coronary artery disease (CAD) more than doubles the risk of death compared with otherwise matched glucose tolerant patients. The biguanide metformin is the drug of choice in treatment of T2DM and has shown to ameliorate cardiovascular morbidity in patients with T2DM and myocardial infarction (MI). The incretin hormone, glucagon-like peptide-1 (GLP-1) improves ?-cell function, insulin sensitivity and causes weight loss and has been suggested to have beneficial effects on cardiac function. The GLP-1 receptor agonist (GLP-1RA), liraglutide, is currently used for treatment of T2DM but its potential effect on cardiac function has not been investigated in detail. We hypothesised that liraglutide added to metformin backbone therapy in patients with CAD and newly diagnosed T2DM will improve ?-cell function and left ventricular systolic function during dobutamine stress. Methods and analyses 40 patients with CAD and newly diagnosed T2DM will receive the intervention liraglutide+metformin and placebo+metformin in this investigator-initiated, double blind, randomised, placebo-controlled, cross-over 12 plus 12?weeks intervention study with a 2-week washout period. The primary cardiovascular end point is changes in left ventricular ejection fraction during stress echocardiography. The primary endocrine end point is ?-cell function evaluated during a frequently sampled intravenous glucose tolerance test. Secondary end points include heart rate variability, diurnal blood pressure, glucagon suppression and inflammatory response (urine, blood and adipose tissue). Ethics and dissemination This study is approved by the Danish Medicines Agency, the Danish Dataprotection Agency and the Regional Committee on Biomedical Research Ethics of the Capital Region of Denmark. The trial will be carried out under the guidance from the GCP unit at Copenhagen University Hospital of Bispebjerg and in accordance with the ICH-GCP guidelines and the Helsinki Declaration. Trial registrations number Clinicaltrials.gov ID: NCT01595789, EudraCT: 2011-005405-78. PMID:25031198

  5. Influence of oxide impurities on the chemical tuning of the thermoelectric properties of substitution derivatives of RuIn{sub 3}

    SciTech Connect

    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 RuIn{sub 3} is performed. Samples with nominal composition Ru{sub 0.95}T{sub 0.05}In{sub 3} (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 RuIn{sub 3}. Minor oxide impurities in the commercially available starting elements, the homogeneity range of RuIn{sub 3} 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 RuIn{sub 3} lead independently to a significant decrease of the total thermal conductivity down to approximately one half of the value observed for binary RuIn{sub 3}, prepared with commercially available starting materials. The electrical resistivity was reduced by substitution and the temperature dependence changes from semiconductor-like, for RuIn{sub 3}, to metal-like in the substitution derivatives. At the same time the sign change in the thermopower at high temperatures, characteristic for binary RuIn{sub 3}, is suppressed, attaining only electrons as majority carriers. - Graphical abstract: Microstructure (perpendicular to the pressure axis; polarized light) of polycrystalline Ru{sub 0.95}Rh{sub 0.05}In{sub 3} (a), Ru{sub 0.95}Ir{sub 0.05}In{sub 3} (b) and Ru{sub 0.95}Re{sub 0.05}In{sub 3} (c) samples after SPS treatment. - Highlights: • Substitution solid solutions of RuIn{sub 3} were prepared via liquid–solid-reaction. • Chemistry of oxide impurities is crucial for explanation of experimental results. • Thermodynamic calculations support the observation of In{sub 2}O{sub 3} or ZnO as impurities. • Electrical resistivity is reduced by substitution. • Temperature dependence of resistivity changes from semiconductor- to metal-like.

  6. Oxygenated Derivatives of Hydrocarbons

    Technology Transfer Automated Retrieval System (TEKTRAN)

    For the book entitled “Insect Hydrocarbons: Biology, Biochemistry and Chemical Ecology”, this chapter presents a comprehensive review of the occurrence, structure and function of oxygenated derivatives of hydrocarbons. The book chapter focuses on the occurrence, structural identification and functi...

  7. 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

  8. Metabolomics based on liquid chromatography with mass spectrometry reveals the chemical difference in the stems and roots derived from Ephedra sinica.

    PubMed

    Lv, Mengying; Chen, Jiaqing; Gao, Yiqiao; Sun, Jianbo; Zhang, Qianqian; Zhang, Mohan; Xu, Fengguo; Zhang, Zunjian

    2015-10-01

    To better understand different traditional uses of the stems (known as Mahuang) and roots (known as Mahuanggen) of Ephedra sinica, their chemical difference should be investigated. In this study, an ultra-fast liquid chromatography coupled with ion trap time-of-flight mass spectrometry untargeted metabolomics approach was established to reveal global chemical difference between Mahuang and Mahuanggen. Clear separation was observed in scores plots of principal component analysis and orthogonal partial least squares-discriminant analysis. Twenty two chemical markers responsible for such separation were screened out and unambiguously/tentatively characterized. Then chemical markers of pharmacologically important ephedrine and pseudoephedrine were absolutely quantified using liquid chromatography coupled with tandem mass spectrometry under multiple reaction monitoring mode. The results showed that Mahuang was rich in ephedrine-type alkaloids, while Mahuanggen was rich in macrocyclic spermine alkaloids. Additionally, different types of flavan-3-ols and flavones exist in Mahuang and Mahuanggen extracts. This research facilitates a better understanding of different traditional uses of Mahuang and Mahuanggen and provides references for chemical analysis of other medicinal plants. PMID:26224607

  9. Synthesis, spectral analysis, X-ray crystal structures and evaluation of chemical reactivity of five new benzoindazole derivatives through experimental and theoretical studies

    NASA Astrophysics Data System (ADS)

    Taib, Layla A.; Faidallah, Hassan M.; ?ahin, Zarife Sibel; Asiri, Abdullah M.; ?ahin, Onur; Arshad, Muhammad Nadeem

    2014-11-01

    The main purpose of this study was synthesis, X-ray, DFT and spectroscopic investigations of the title compounds (I-V). Five new compounds were synthesized and the detailed experimental results are reported. The crystal and molecular structures of the title compounds have been determined by IR, 1H NMR, 13C NMR and single-crystal X-ray diffraction. Molecular geometries from X-ray experiment of I-V in the ground state have been compared using the Density Functional Theory (DFT) with B3LYP/6-31G(d,p) basis set. In addition, the molecular electrostatic potential maps and frontier molecular orbitals were performed at B3LYP/6-31G(d,p) level of theory. DFT global chemical reactivity descriptors (chemical hardness, total energy, electronic chemical potential and electrophilicity) are calculated for the title molecules and used to predict their relative stability and reactivity.

  10. 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.

  11. Optical fiber chemical sensors with sol-gel derived nanomaterials for monitoring high temperature/high pressure reactions in clean energy technologies

    NASA Astrophysics Data System (ADS)

    Tao, Shiquan

    2010-04-01

    The development of sensor technologies for in situ, real time monitoring the high temperature/high pressure (HTP) chemical processes used in clean energy technologies is a tough challenge, due to the HTP, high dust and corrosive chemical environment of the reaction systems. A silica optical fiber is corrosive resistance, and can work in HTP conditions. This paper presents our effort in developing fiber optic sensors for in situ, real time monitoring the concentration of trace ammonia and hydrogen in high temperature gas samples. Preliminary test results illustrate the feasibility of using fiber optic sensor technologies for monitoring HTP processes for next generation energy industry.

  12. Assessment of the Ecological Risks of Endocrine-Disrupting Chemicals (EDCs): Derivation of WQC and Consideration of Concentrated Animal Feeding Operations as a Source

    EPA Science Inventory

    The occurrence of endocrine-disrupting chemicals (EDCs) in the environment has been associated with impacts on fish. Hence, there is a need for numerical water quality criteria (WQC) for the protection of aquatic life from adverse effects of EDCs. However, EDCs have some unique...

  13. 40 CFR 721.9658 - Thiadiazole derivative.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...2010-07-01 false Thiadiazole derivative. 721.9658 Section 721.9658...Substances § 721.9658 Thiadiazole derivative. (a) Chemical substance and significant...substance identified as a thiadiazole derivative (PMN P-94-1631) is subject...

  14. 40 CFR 721.9658 - Thiadiazole derivative.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...2011-07-01 false Thiadiazole derivative. 721.9658 Section 721.9658...Substances § 721.9658 Thiadiazole derivative. (a) Chemical substance and significant...substance identified as a thiadiazole derivative (PMN P-94-1631) is subject...

  15. 40 CFR 721.1820 - Bisphenol derivative.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 2010-07-01 false Bisphenol derivative. 721.1820 Section 721.1820...Substances § 721.1820 Bisphenol derivative. (a) Chemical substance and significant...substance identified generically as bisphenol derivative (PMN No. P-92-509) is...

  16. 40 CFR 721.5913 - Phenothiazine derivative.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...2011-07-01 false Phenothiazine derivative. 721.5913 Section 721.5913...Substances § 721.5913 Phenothiazine derivative. (a) Chemical substance and significant...identified generically as a phenothiazine derivative (PMN P-96-813) is subject...

  17. 40 CFR 721.5913 - Phenothiazine derivative.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...2010-07-01 false Phenothiazine derivative. 721.5913 Section 721.5913...Substances § 721.5913 Phenothiazine derivative. (a) Chemical substance and significant...identified generically as a phenothiazine derivative (PMN P-96-813) is subject...

  18. 40 CFR 721.1820 - Bisphenol derivative.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 2011-07-01 false Bisphenol derivative. 721.1820 Section 721.1820...Substances § 721.1820 Bisphenol derivative. (a) Chemical substance and significant...substance identified generically as bisphenol derivative (PMN No. P-92-509) is...

  19. 40 CFR 721.10672 - Sodium olefin sulfonate derivative (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...2014-07-01 2014-07-01 false Sodium olefin sulfonate derivative (generic...Chemical Substances § 721.10672 Sodium olefin sulfonate derivative (generic...chemical substances identified generically as sodium olefin sulfonate derivative...

  20. 40 CFR 721.10317 - Alkyl phosphate derivative (generic).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...2012-07-01 2012-07-01 false Alkyl phosphate derivative (generic). 721.10317...Chemical Substances § 721.10317 Alkyl phosphate derivative (generic). (a) Chemical...substance identified generically as alkyl phosphate derivative (PMN P-02-1040)...

  1. 40 CFR 721.10317 - Alkyl phosphate derivative (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...2013-07-01 2013-07-01 false Alkyl phosphate derivative (generic). 721.10317...Chemical Substances § 721.10317 Alkyl phosphate derivative (generic). (a) Chemical...substance identified generically as alkyl phosphate derivative (PMN P-02-1040)...

  2. 40 CFR 721.10317 - Alkyl phosphate derivative (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...2014-07-01 2014-07-01 false Alkyl phosphate derivative (generic). 721.10317...Chemical Substances § 721.10317 Alkyl phosphate derivative (generic). (a) Chemical...substance identified generically as alkyl phosphate derivative (PMN P-02-1040)...

  3. Some Phthalocyanine and Naphthalocyanine Derivatives as Corrosion Inhibitors for Aluminium in Acidic Medium: Experimental, Quantum Chemical Calculations, QSAR Studies and Synergistic Effect of Iodide Ions.

    PubMed

    Dibetsoe, Masego; Olasunkanmi, Lukman O; Fayemi, Omolola E; Yesudass, Sasikumar; Ramaganthan, Baskar; Bahadur, Indra; Adekunle, Abolanle S; Kabanda, Mwadham M; Ebenso, Eno E

    2015-01-01

    The effects of seven macrocyclic compounds comprising four phthalocyanines (Pcs) namely 1,4,8,11,15,18,22,25-octabutoxy-29H,31H-phthalocyanine (Pc1), 2,3,9,10,16,17,23,24-octakis(octyloxy)-29H,31H-phthalocyanine (Pc2), 2,9,16,23-tetra-tert-butyl-29H,31H-phthalocyanine (Pc3) and 29H,31H-phthalocyanine (Pc4), and three naphthalocyanines namely 5,9,14,18,23,27,32,36-octabutoxy-2,3-naphthalocyanine (nPc1), 2,11,20,29-tetra-tert-butyl-2,3-naphthalocyanine (nPc2) and 2,3-naphthalocyanine (nP3) were investigated on the corrosion of aluminium (Al) in 1 M HCl using a gravimetric method, potentiodynamic polarization technique, quantum chemical calculations and quantitative structure activity relationship (QSAR). Synergistic effects of KI on the corrosion inhibition properties of the compounds were also investigated. All the studied compounds showed appreciable inhibition efficiencies, which decrease with increasing temperature from 30 °C to 70 °C. At each concentration of the inhibitor, addition of 0.1% KI increased the inhibition efficiency compared to the absence of KI indicating the occurrence of synergistic interactions between the studied molecules and I(-) ions. From the potentiodynamic polarization studies, the studied Pcs and nPcs are mixed type corrosion inhibitors both without and with addition of KI. The adsorption of the studied molecules on Al surface obeys the Langmuir adsorption isotherm, while the thermodynamic and kinetic parameters revealed that the adsorption of the studied compounds on Al surface is spontaneous and involves competitive physisorption and chemisorption mechanisms. The experimental results revealed the aggregated interactions between the inhibitor molecules and the results further indicated that the peripheral groups on the compounds affect these interactions. The calculated quantum chemical parameters and the QSAR results revealed the possibility of strong interactions between the studied inhibitors and metal surface. QSAR analysis on the quantum chemical parameters obtained with B3LYP/6-31G (d,p) method show that a combination of two quantum chemical parameters to form a composite index provides the best correlation with the experimental data. PMID:26343626

  4. Identification of UV-protective Activators of Nuclear Factor Erythroid-derived 2-Related Factor 2 (Nrf2) by Combining a Chemical Library Screen with Computer-based Virtual Screening*

    PubMed Central

    Lieder, Franziska; Reisen, Felix; Geppert, Tim; Sollberger, Gabriel; Beer, Hans-Dietmar; auf dem Keller, Ulrich; Schäfer, Matthias; Detmar, Michael; Schneider, Gisbert; Werner, Sabine

    2012-01-01

    Nuclear factor erythroid-derived 2-related factor 2 (Nrf2) is a master regulator of cellular antioxidant defense systems, and activation of this transcription factor is a promising strategy for protection of skin and other organs from environmental insults. To identify efficient Nrf2 activators in keratinocytes, we combined a chemical library screen with computer-based virtual screening. Among 14 novel Nrf2 activators, the most potent compound, a nitrophenyl derivative of 2-chloro-5-nitro-N-phenyl-benzamide, was characterized with regard to its molecular mechanism of action. This compound induced the expression of cytoprotective genes in keratinocytes isolated from wild-type but not from Nrf2-deficient mice. Most importantly, it showed low toxicity and protected primary human keratinocytes from UVB-induced cell death. Therefore, it represents a potential lead compound for the development of drugs for skin protection under stress conditions. Our study demonstrates that chemical library screening combined with advanced computational similarity searching is a powerful strategy for identification of bioactive compounds, and it points toward an innovative therapeutic approach against UVB-induced skin damage. PMID:22851183

  5. 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

  6. 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.

  7. 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...

  8. 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...

  9. The integration of data on physico-chemical properties, in vitro-derived toxicity data and physiologically based kinetic and dynamic as modelling a tool in hazard and risk assessment. A commentary.

    PubMed

    Blaauboer, B J

    2003-02-18

    Toxicity of a compound for an organism is dependent on the route of exposure, the amount (or concentration), the way in which the compound is taken up, distributes and is eliminated from the organism (ADME, kinetics) and the intrinsic properties (reactivity; mode of action, dynamics) of the compound towards the organism. These three elements: exposure, kinetics and dynamics form the basis of hazard and risk evaluations. Developments in our knowledge of the way in which physico-chemical properties of chemicals (on the one side) and physiological processes in the organism (on the other side) determine a compound's toxicity have greatly increased our understanding of toxicological processes and our ability to interpret experimental results. This has now resulted in the development of model systems in which the above-mentioned processes can be described mathematically. Biokinetic modelling is currently of great interest, but the further development of toxicodynamic modelling is equally important. The combination of both allows the estimation of a compound's critical amount/concentration on the critical site of action, which ideally would be the basis for hazard and risk assessments. In vitro systems have been extremely useful in studying the molecular basis of a chemical's biological activity, including its mechanism(s) of toxic action. Other achievements include the prediction of biological reactivity on the basis of a compound's physico-chemical properties and the construction of quantitative structure-activity relationships (QSARs). However, for the incorporation of in vitro-derived data as well as the results of QSARs, kinetic modelling is indispensable. Thus, biokinetic and toxicodynamic modelling are important (if not crucial) tools in toxicological research and there are increasing opportunities to incorporate the results of this work in hazard and risk assessments. Their implementation will allow a much more scientifically-based and a better structured risk assessment, which will be to a much lesser extent relying on animal experimentation. PMID:12559700

  10. Evaluating Whole Chemical Mixtures and Sufficient Similarity

    EPA Science Inventory

    This powerpoint presentation supports apresentation describing dose-response assessment for complex chemical mixtures including deriving reference doses for mixtures evaluating sufficient similarity among chemical mixtures.

  11. 40 CFR 721.1820 - Bisphenol derivative.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Bisphenol derivative. 721.1820 Section... Substances § 721.1820 Bisphenol derivative. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as bisphenol derivative (PMN No. P-92-509)...

  12. 40 CFR 721.1820 - Bisphenol derivative.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Bisphenol derivative. 721.1820 Section... Substances § 721.1820 Bisphenol derivative. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as bisphenol derivative (PMN No. P-92-509)...

  13. 40 CFR 721.1820 - Bisphenol derivative.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Bisphenol derivative. 721.1820 Section... Substances § 721.1820 Bisphenol derivative. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as bisphenol derivative (PMN No. P-92-509)...

  14. 40 CFR 721.1820 - Bisphenol derivative.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Bisphenol derivative. 721.1820 Section... Substances § 721.1820 Bisphenol derivative. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as bisphenol derivative (PMN No. P-92-509)...

  15. 40 CFR 721.1820 - Bisphenol derivative.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Bisphenol derivative. 721.1820 Section... Substances § 721.1820 Bisphenol derivative. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as bisphenol derivative (PMN No. P-92-509)...

  16. Can Small Chemical Modifications of Natural Pan-inhibitors Modulate the Biological Selectivity? The Case of Curcumin Prenylated Derivatives Acting as HDAC or mPGES-1 Inhibitors.

    PubMed

    Iranshahi, Mehrdad; Chini, Maria Giovanna; Masullo, Milena; Sahebkar, Amirhossein; Javidnia, Azita; Chitsazian Yazdi, Mahsa; Pergola, Carlo; Koeberle, Andreas; Werz, Oliver; Pizza, Cosimo; Terracciano, Stefania; Piacente, Sonia; Bifulco, Giuseppe

    2015-12-24

    Curcumin, or diferuloylmethane, a polyphenolic molecule isolated from the rhizome of Curcuma longa, is reported to modulate multiple molecular targets involved in cancer and inflammatory processes. On the basis of its pan-inhibitory characteristics, here we show that simple chemical modifications of the curcumin scaffold can regulate its biological selectivity. In particular, the curcumin scaffold was modified with three types of substituents at positions C-1, C-8, and/or C-8' [C5 (isopentenyl, 5-8), C10 (geranyl, 9-12), and C15 (farnesyl, 13, 14)] in order to make these molecules more selective than the parent compound toward two specific targets: histone deacetylase (HDAC) and microsomal prostaglandin E2 synthase-1 (mPGES-1). From combined in silico and in vitro analyses, three selective inhibitors by proper substitution at position 8 were revealed. Compound 13 has improved HDAC inhibitory activity and selectivity with respect to the parent compound, while 5 and 9 block the mPGES-1 enzyme. We hypothesize about the covalent interaction of curcumin, 5, and 9 with the mPGES-1 binding site. PMID:26588603

  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 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.

  19. 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.

  20. Biotechnology and derived products

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Microorganisms able to infect and kill insect pests, metabolites from plants and microorganisms, and transgenic crops are biotechnologically derived products that are being promoted for use to control insect pests in lieu of chemical insecticides. Products based on these technologies effectively co...

  1. 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.

  2. Design, chemical synthesis and biological evaluation of 3-spiromorpholinone/3-spirocarbamate androsterone derivatives as inhibitors of 17?-hydroxysteroid dehydrogenase type 3.

    PubMed

    Djigoué, Guy Bertrand; Kenmogne, Lucie Carolle; Roy, Jenny; Maltais, René; Poirier, Donald

    2015-09-01

    17?-Hydroxysteroid dehydrogenase type 3 (17?-HSD3) is a key enzyme involved in the biosynthesis of testosterone and dihydrotestosterone. These hormones are known to stimulate androgen-dependent prostate cancer. In order to generate effective inhibitors of androgen biosynthesis without androgenic effect, we synthesized a new family of 3-spiromorpholinone and 3-spirocarbamate androsterone derivatives bearing diversified hydrophobic groups. We also tested their inhibitory activity in a microsomal fraction of 17?-HSD3-containing rat testes, and their androgenic effect on androgen-sensitive LAPC-4 cells. From our first structure-activity relationship (SAR) study, we noted that compound 7e inhibited 17?-HSD3 (77% at 0.1 ?M) compared to our reference compound RM-532-105 (76% at 0.1 ?M), but exhibited a residual androgenic effect. A library of 7e analogue compounds was next synthesized in order to generate compounds with reduced androgenic activity. In this new SAR study, the sulfonamide compound 7e21 and the carboxamide compound 7e22 inhibited 17?-HSD3 (IC50 = 28 and 88 nM, respectively). These two compounds were not androgenic and not cytotoxic even at the highest concentration tested, but their inhibitory activity decreased in intact LNCaP cells overexpressing 17?-HSD3 (LNCaP[17?-HSD3]). Structural modifications of these two lead compounds could however be tested to produce a second generation of 17?-HSD3 inhibitors. PMID:26277760

  3. 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.

  4. Seven New and Two Known Lipopeptides as well as Five Known Polyketides: The Activated Production of Silent Metabolites in a Marine-Derived Fungus by Chemical Mutagenesis Strategy Using Diethyl Sulphate

    PubMed Central

    Wu, Chang-Jing; Li, Chang-Wei; Cui, Cheng-Bin

    2014-01-01

    AD-2-1 is an antitumor fungal mutant obtained by diethyl sulfate mutagenesis of a marine-derived Penicillium purpurogenum G59. The G59 strain originally did not produce any metabolites with antitumor activities in MTT assays using K562 cells. Tracing newly produced metabolites under guidance of MTT assay and TLC analysis by direct comparison with control G59 extract, seven new (1–7) and two known (8–9) lipopeptides were isolated together with five known polyketides 10–14 from the extract of mutant AD-2-1. Structures of the seven new compounds including their absolute configurations were determined by spectroscopic and chemical evidences and named as penicimutalides A–G (1–7). Seven known compounds were identified as fellutamide B (8), fellutamide C (9), 1?-O-methylaverantin (10), averantin (11), averufin (12), nidurufin (13), and sterigmatocystin (14). In the MTT assay, 1–14 inhibited several human cancer cell lines to varying extents. All the bioassays and HPLC-photodiode array detector (PDAD)-UV and HPLC-electron spray ionization (ESI)-MS analyses demonstrated that the production of 1–14 in the mutant AD-2-1 was caused by the activated production of silent metabolites in the original G59 fungal strain. Present results provided additional examples for effectiveness of the chemical mutagenesis strategy using diethyl sulphate mutagenesis to discover new compounds by activating silent metabolites in fungal isolates. PMID:24686557

  5. 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...

  6. 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...

  7. Inquiry of the electron density transfers in chemical reactions: a complete reaction path for the denitrogenation process of 2,3-diazabicyclo[2.2.1]hept-2-ene derivatives.

    PubMed

    Safont, Vicent S; González-Navarrete, Patricio; Oliva, Mónica; Andrés, Juan

    2015-12-01

    A detailed study on all stages associated with the reaction mechanisms for the denitrogenation of 2,3-diazabicyclo[2.2.1]hept-2-ene derivatives (DBX, with X substituents at the methano-bridge carbon atom, X = H and OH) is presented. In particular, we have characterized the processes leading to cycloalkene derivatives through migration-type mechanisms as well as the processes leading to cyclopentil-1,3-diradical species along concerted or stepwise pathways. The reaction mechanisms have been further analysed within the bonding evolution theory framework at B3LYP and M05-2X/6-311+G(2d,p) levels of theory. Analysis of the results allows us to obtain the intimate electronic mechanism for the studied processes, providing a new topological picture of processes underlying the correlation between the experimental measurements obtained by few-optical-cycle visible pulse radiation and the quantum topological analysis of the electron localization function (ELF) in terms of breaking/forming processes along this chemical rearrangement. The evolution of the population of the disynaptic basin V(N1,N2) can be related to the experimental observation associated with the N[double bond, length as m-dash]N stretching mode evolution, relative to the N2 release, along the reaction process. This result allows us to determine why the N2 release is easier for the DBH case via a concerted mechanism compared to the stepwise mechanism found in the DBOH system. This holds the key to unprecedented insight into the mapping of the electrons making/breaking the bonds while the bonds change. PMID:26584857

  8. 40 CFR 721.646 - Aminofluoran derivative (generic name).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...2010-07-01 false Aminofluoran derivative (generic name). 721.646 Section...Substances § 721.646 Aminofluoran derivative (generic name). (a) Chemical...identified generically as aminofluoran derivative (PMN P-95-512) is subject...

  9. 40 CFR 721.1760 - Substituted benzotriazole derivatives.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... false Substituted benzotriazole derivatives. 721.1760 Section 721.1760...721.1760 Substituted benzotriazole derivatives. (a) Chemical substances and significant...generically as substituted benzotriazole derivatives (PMNs P-93-374 and...

  10. 40 CFR 721.5925 - Bis heterocyclic phenylene derivative (generic).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... false Bis heterocyclic phenylene derivative (generic). 721.5925 Section...5925 Bis heterocyclic phenylene derivative (generic). (a) Chemical substance...generically as bis heterocyclic phenylene derivative (PMN P-01-0432) is subject...

  11. 40 CFR 721.2025 - Substituted phenylimino carbamate derivative.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Substituted phenylimino carbamate derivative. 721.2025 Section 721.2025... Substituted phenylimino carbamate derivative. (a) Chemical substance and significant...as a substituted phenylimino carbamate derivative (PMN P-91-487) is subject...

  12. 40 CFR 721.646 - Aminofluoran derivative (generic name).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...2011-07-01 false Aminofluoran derivative (generic name). 721.646 Section...Substances § 721.646 Aminofluoran derivative (generic name). (a) Chemical...identified generically as aminofluoran derivative (PMN P-95-512) is subject...

  13. 40 CFR 721.9740 - Brominated triazine derivative.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...2011-07-01 false Brominated triazine derivative. 721.9740 Section 721.9740... § 721.9740 Brominated triazine derivative. (a) Chemical substance and significant...generically as a brominated triazine derivative (PMN P-91-403) is subject...

  14. 40 CFR 721.2025 - Substituted phenylimino carbamate derivative.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Substituted phenylimino carbamate derivative. 721.2025 Section 721.2025... Substituted phenylimino carbamate derivative. (a) Chemical substance and significant...as a substituted phenylimino carbamate derivative (PMN P-91-487) is subject...

  15. 40 CFR 721.5925 - Bis heterocyclic phenylene derivative (generic).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... false Bis heterocyclic phenylene derivative (generic). 721.5925 Section...5925 Bis heterocyclic phenylene derivative (generic). (a) Chemical substance...generically as bis heterocyclic phenylene derivative (PMN P-01-0432) is subject...

  16. 40 CFR 721.10172 - Alkylamide derivative (generic).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 2011-07-01 false Alkylamide derivative (generic). 721.10172 Section...Substances § 721.10172 Alkylamide derivative (generic). (a) Chemical substance...identified generically as alkylamide derivative (PMN P-03-633) is subject...

  17. 40 CFR 721.9740 - Brominated triazine derivative.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...2010-07-01 false Brominated triazine derivative. 721.9740 Section 721.9740... § 721.9740 Brominated triazine derivative. (a) Chemical substance and significant...generically as a brominated triazine derivative (PMN P-91-403) is subject...

  18. 40 CFR 721.9079 - Dihydro quinacridone derivative (generic).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...2011-07-01 false Dihydro quinacridone derivative (generic). 721.9079 Section... § 721.9079 Dihydro quinacridone derivative (generic). (a) Chemical substance...identified generically as dihydro quinacridone derivative (PMN P-01-397) is subject...

  19. 40 CFR 721.9079 - Dihydro quinacridone derivative (generic).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...2010-07-01 false Dihydro quinacridone derivative (generic). 721.9079 Section... § 721.9079 Dihydro quinacridone derivative (generic). (a) Chemical substance...identified generically as dihydro quinacridone derivative (PMN P-01-397) is subject...

  20. 40 CFR 721.10172 - Alkylamide derivative (generic).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 2010-07-01 false Alkylamide derivative (generic). 721.10172 Section...Substances § 721.10172 Alkylamide derivative (generic). (a) Chemical substance...identified generically as alkylamide derivative (PMN P-03-633) is subject...

  1. 40 CFR 721.1760 - Substituted benzotriazole derivatives.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... false Substituted benzotriazole derivatives. 721.1760 Section 721.1760...721.1760 Substituted benzotriazole derivatives. (a) Chemical substances and significant...generically as substituted benzotriazole derivatives (PMNs P-93-374 and...

  2. 40 CFR 721.2025 - Substituted phenylimino carbamate derivative.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...2014-07-01 false Substituted phenylimino carbamate derivative. 721.2025 Section 721...721.2025 Substituted phenylimino carbamate derivative. (a) Chemical substance...generically as a substituted phenylimino carbamate derivative (PMN P-91-487)...

  3. 40 CFR 721.2025 - Substituted phenylimino carbamate derivative.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...2013-07-01 false Substituted phenylimino carbamate derivative. 721.2025 Section 721...721.2025 Substituted phenylimino carbamate derivative. (a) Chemical substance...generically as a substituted phenylimino carbamate derivative (PMN P-91-487)...

  4. 40 CFR 721.2025 - Substituted phenylimino carbamate derivative.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...2012-07-01 false Substituted phenylimino carbamate derivative. 721.2025 Section 721...721.2025 Substituted phenylimino carbamate derivative. (a) Chemical substance...generically as a substituted phenylimino carbamate derivative (PMN P-91-487)...

  5. Derivative chameleons

    SciTech Connect

    Noller, Johannes

    2012-07-01

    We consider generalized chameleon models where the conformal coupling between matter and gravitational geometries is not only a function of the chameleon field ?, but also of its derivatives via higher order co-ordinate invariants (such as ?{sub ?}??{sup ?}?,??,...). Specifically we consider the first such non-trivial conformal factor A(?,?{sub ?}??{sup ?}?). The associated phenomenology is investigated and we show that such theories have a new generic mass-altering mechanism, potentially assisting the generation of a sufficiently large chameleon mass in dense environments. The most general effective potential is derived for such derivative chameleon setups and explicit examples are given. Interestingly this points us to the existence of a purely derivative chameleon protected by a shift symmetry for ? ? ?+c. We also discuss potential ghost-like instabilities associated with mass-lifting mechanisms and find another, mass-lowering and instability-free, branch of solutions. This suggests that, barring fine-tuning, stable derivative models are in fact typically anti-chameleons that suppress the field's mass in dense environments. Furthermore we investigate modifications to the thin-shell regime and prove a no-go theorem for chameleon effects in non-conformal geometries of the disformal type.

  6. Derivative Chameleons

    E-print Network

    Johannes Noller

    2012-03-29

    We consider generalized chameleon models where the conformal coupling between matter and gravitational geometries is not only a function of the chameleon field \\phi, but also of its derivatives via higher order co-ordinate invariants. Specifically we consider the first such non-trivial conformal factor A(\\phi,X), where X is the canonical kinetic term for \\phi. The associated phenomenology is investigated and we show that such theories have a new generic mass-altering mechanism, potentially assisting the generation of a sufficiently large chameleon mass in dense environments. The most general effective potential is derived for such derivative chameleon setups and explicit examples are given. Interestingly this points us to the existence of a purely derivative chameleon protected by a shift symmetry for \\phi. We also discuss potential ghost-like instabilities associated with mass-lifting mechanisms and find another, mass-lowering and instability-free, branch of solutions. This suggests that, barring fine-tuning, stable derivative models are in fact typically anti-chameleons that suppress the field's mass in dense environments. Furthermore we investigate modifications to the thin-shell regime and prove a no-go theorem for chameleon effects in non-conformal geometries of the disformal type.

  7. Derivative chameleons

    NASA Astrophysics Data System (ADS)

    Noller, Johannes

    2012-07-01

    We consider generalized chameleon models where the conformal coupling between matter and gravitational geometries is not only a function of the chameleon field phi, but also of its derivatives via higher order co-ordinate invariants (such as ??phi??phi,squphi,...). Specifically we consider the first such non-trivial conformal factor A(phi,??phi??phi). The associated phenomenology is investigated and we show that such theories have a new generic mass-altering mechanism, potentially assisting the generation of a sufficiently large chameleon mass in dense environments. The most general effective potential is derived for such derivative chameleon setups and explicit examples are given. Interestingly this points us to the existence of a purely derivative chameleon protected by a shift symmetry for phi ? phi+c. We also discuss potential ghost-like instabilities associated with mass-lifting mechanisms and find another, mass-lowering and instability-free, branch of solutions. This suggests that, barring fine-tuning, stable derivative models are in fact typically anti-chameleons that suppress the field's mass in dense environments. Furthermore we investigate modifications to the thin-shell regime and prove a no-go theorem for chameleon effects in non-conformal geometries of the disformal type.

  8. Chemical Emergencies

    MedlinePLUS

    When a hazardous chemical has been released, it may harm people's health. Chemical releases can be unintentional, as in the case of an ... the case of a terrorist attack with a chemical weapon. Some hazardous chemicals have been developed by ...

  9. Chemical Peels

    MedlinePLUS

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

  10. 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.

  11. 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.

  12. 40 CFR 721.10317 - Alkyl phosphate derivative (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Alkyl phosphate derivative (generic... Specific Chemical Substances § 721.10317 Alkyl phosphate derivative (generic). (a) Chemical substance and... phosphate derivative (PMN P-02-1040) is subject to reporting under this section for the significant new...

  13. 40 CFR 721.10317 - Alkyl phosphate derivative (generic).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Alkyl phosphate derivative (generic... Specific Chemical Substances § 721.10317 Alkyl phosphate derivative (generic). (a) Chemical substance and... phosphate derivative (PMN P-02-1040) is subject to reporting under this section for the significant new...

  14. 40 CFR 721.10317 - Alkyl phosphate derivative (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Alkyl phosphate derivative (generic... Specific Chemical Substances § 721.10317 Alkyl phosphate derivative (generic). (a) Chemical substance and... phosphate derivative (PMN P-02-1040) is subject to reporting under this section for the significant new...

  15. 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)

  16. Chemical Microsensors For Detection Of Explosives And Chemical Warfare Agents

    DOEpatents

    Yang, Xiaoguang (Los Alamos, NM); Swanson, Basil I. (Los Alamos, NM)

    2001-11-13

    An article of manufacture is provided including a substrate having an oxide surface layer and a layer of a cyclodextrin derivative chemically bonded to said substrate, said layer of a cyclodextrin derivative adapted for the inclusion of selected compounds, e.g., nitro-containing organic compounds, therewith. Such an article can be a chemical microsensor capable of detecting a resultant mass change from inclusion of the nitro-containing organic compound.

  17. 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...

  18. 40 CFR 721.1230 - Benzene, ethenyl-, ar-bromo derivatives.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...2012-07-01 2012-07-01 false Benzene, ethenyl-, ar-bromo derivatives...Specific Chemical Substances § 721.1230 Benzene, ethenyl-, ar-bromo derivatives...The chemical substance identified as benzene, ethenyl-, ar-bromo...

  19. 40 CFR 721.1240 - Benzene, (2-bromoethyl)-, ar-bromo derivatives.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...2012-07-01 2012-07-01 false Benzene, (2-bromoethyl)-, ar-bromo derivatives...Specific Chemical Substances § 721.1240 Benzene, (2-bromoethyl)-, ar-bromo derivatives...The chemical substance identified as benzene, (2-bromoethyl)-,...

  20. 40 CFR 721.1230 - Benzene, ethenyl-, ar-bromo derivatives.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...2013-07-01 2013-07-01 false Benzene, ethenyl-, ar-bromo derivatives...Specific Chemical Substances § 721.1230 Benzene, ethenyl-, ar-bromo derivatives...The chemical substance identified as benzene, ethenyl-, ar-bromo...

  1. 40 CFR 721.1240 - Benzene, (2-bromoethyl)-, ar-bromo derivatives.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...2014-07-01 2014-07-01 false Benzene, (2-bromoethyl)-, ar-bromo derivatives...Specific Chemical Substances § 721.1240 Benzene, (2-bromoethyl)-, ar-bromo derivatives...The chemical substance identified as benzene, (2-bromoethyl)-,...

  2. 40 CFR 721.1230 - Benzene, ethenyl-, ar-bromo derivatives.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...2014-07-01 2014-07-01 false Benzene, ethenyl-, ar-bromo derivatives...Specific Chemical Substances § 721.1230 Benzene, ethenyl-, ar-bromo derivatives...The chemical substance identified as benzene, ethenyl-, ar-bromo...

  3. 40 CFR 721.1240 - Benzene, (2-bromoethyl)-, ar-bromo derivatives.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...2013-07-01 2013-07-01 false Benzene, (2-bromoethyl)-, ar-bromo derivatives...Specific Chemical Substances § 721.1240 Benzene, (2-bromoethyl)-, ar-bromo derivatives...The chemical substance identified as benzene, (2-bromoethyl)-,...

  4. Chemical biology of abscisic acid.

    PubMed

    Kitahata, Nobutaka; Asami, Tadao

    2011-07-01

    Chemical biology is a discipline that utilizes chemicals to elucidate biological mechanisms and physiological functions. Various abscisic acid (ABA) derivatives have revealed the structural requirement for the perception by ABA receptors while biotin or caged derivatives of ABA have disclosed the localization of several ABA-binding proteins. Recently, selective ABA agonist has been used to identify ABA receptors. Furthermore, ABA biosynthesis and catabolic inhibitors have contributed to the identification of new ABA functions in plant growth and development. The physiological function of ABA in non-plant organisms has gradually been revealed. In this review, we discuss the development of small bioactive chemicals and their significance in ABA research. PMID:21461661

  5. 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

  6. 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.

  7. 40 CFR 721.10328 - Salt of polyalkylenepolyamine derivative (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Salt of polyalkylenepolyamine... Specific Chemical Substances § 721.10328 Salt of polyalkylenepolyamine derivative (generic). (a) Chemical... as salt of polyalkylenepolyamine derivative (PMN P-03-530) is subject to reporting under this...

  8. 40 CFR 721.10328 - Salt of polyalkylenepolyamine derivative (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Salt of polyalkylenepolyamine... Specific Chemical Substances § 721.10328 Salt of polyalkylenepolyamine derivative (generic). (a) Chemical... as salt of polyalkylenepolyamine derivative (PMN P-03-530) is subject to reporting under this...

  9. 40 CFR 721.10328 - Salt of polyalkylenepolyamine derivative (generic).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Salt of polyalkylenepolyamine... Specific Chemical Substances § 721.10328 Salt of polyalkylenepolyamine derivative (generic). (a) Chemical... as salt of polyalkylenepolyamine derivative (PMN P-03-530) is subject to reporting under this...

  10. 40 CFR 721.6097 - Phosphoric acid derivative (generic name).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Phosphoric acid derivative (generic name). 721.6097 Section 721.6097 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED... Specific Chemical Substances § 721.6097 Phosphoric acid derivative (generic name). (a) Chemical...

  11. 40 CFR 721.430 - Oxo-substituted amino-al-kanoic acid derivative.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... false Oxo-substituted amino-al-kanoic acid derivative. 721.430...430 Oxo-substituted amino-al-kanoic acid derivative. (a) Chemical...generically as oxo-substituted amino al-kan-oic acid derivative (PMN No....

  12. 40 CFR 721.430 - Oxo-substituted amino-al-kanoic acid derivative.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... false Oxo-substituted amino-al-kanoic acid derivative. 721.430...430 Oxo-substituted amino-al-kanoic acid derivative. (a) Chemical...generically as oxo-substituted amino al-kan-oic acid derivative (PMN No....

  13. 40 CFR 721.430 - Oxo-substituted amino-al-kanoic acid derivative.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... false Oxo-substituted amino-al-kanoic acid derivative. 721.430...430 Oxo-substituted amino-al-kanoic acid derivative. (a) Chemical...generically as oxo-substituted amino al-kan-oic acid derivative (PMN No....

  14. 40 CFR 721.430 - Oxo-substituted amino-al-kanoic acid derivative.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... false Oxo-substituted amino-al-kanoic acid derivative. 721.430...430 Oxo-substituted amino-al-kanoic acid derivative. (a) Chemical...generically as oxo-substituted amino al-kan-oic acid derivative (PMN No....

  15. 40 CFR 721.430 - Oxo-substituted amino-al-kanoic acid derivative.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... false Oxo-substituted amino-al-kanoic acid derivative. 721.430...430 Oxo-substituted amino-al-kanoic acid derivative. (a) Chemical...generically as oxo-substituted amino al-kan-oic acid derivative (PMN No....

  16. 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...derivative, phosphoric acid esters, potassium salts. (a) Chemical substance and...derivative, phosphoric acid esters, potassium salts (PMN P-91-818) is...

  17. 40 CFR 721.6110 - Alkyldi(alkyloxyhydroxypropyl) derivative, phosphoric acid esters, potassium salts.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...derivative, phosphoric acid esters, potassium salts. 721.6110 Section 721...derivative, phosphoric acid esters, potassium salts. (a) Chemical substance and...derivative, phosphoric acid esters, potassium salts (PMN P-91-818) is...

  18. 40 CFR 721.6110 - Alkyldi(alkyloxyhydroxypropyl) derivative, phosphoric acid esters, potassium salts.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...derivative, phosphoric acid esters, potassium salts. 721.6110 Section 721...derivative, phosphoric acid esters, potassium salts. (a) Chemical substance and...derivative, phosphoric acid esters, potassium salts (PMN P-91-818) is...

  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...derivative, phosphoric acid esters, potassium salts. (a) Chemical substance and...derivative, phosphoric acid esters, potassium salts (PMN P-91-818) is...

  20. 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...derivative, phosphoric acid esters, potassium salts. (a) Chemical substance and...derivative, phosphoric acid esters, potassium salts (PMN P-91-818) is...

  1. 40 CFR 721.3560 - Derivative of tetra-chloro-ethy-lene.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...2011-07-01 2011-07-01 false Derivative of tetra-chloro-ethy-lene. ...Chemical Substances § 721.3560 Derivative of tetra-chloro-ethy-lene. ...paragraph (a)(2) of this section: Derivative of tetrachloroethylene,...

  2. 40 CFR 721.3560 - Derivative of tetra-chloro-ethy-lene.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...2010-07-01 2010-07-01 false Derivative of tetra-chloro-ethy-lene. ...Chemical Substances § 721.3560 Derivative of tetra-chloro-ethy-lene. ...paragraph (a)(2) of this section: Derivative of tetrachloroethylene,...

  3. Drug laws and the 'derivative' problem.

    PubMed

    King, Leslie A; Ujváry, István; Brandt, Simon D

    2014-01-01

    The concept of a 'derivative' is used widely in chemistry, where its precise meaning depends on the circumstances. However, numerous examples of derivative also occur in domestic drugs legislation, some of which stem from the 1961 United Nations Single Convention on Narcotic Drugs. There is a commonly held view that only 'first-order' derivatives should be considered: substances that can be created from a parent structure in a single chemical reaction. In other words, 'derivatives of derivatives' are excluded. However, some substances related to ecgonine (e.g. 2-carbomethoxytropinone) are clearly convertible to cocaine, even though this may require more than one reaction step. It follows that 2-carbomethoxytropinone is a controlled drug, a situation that most chemists would regard as perverse. A more extreme example of the complexity of 'derivative' is shown by the conversion of thebaine to buprenorphine. Even though this requires six or more stages, the US Drug Enforcement Administration successfully argued in a 1986 case that for the purposes of the Controlled Substances Act, the number of steps required was irrelevant; buprenorphine was a derivative of thebaine. Because the term derivative is rarely defined in statutes, the legal status of some substances, such as 2-bromo-LSD, is uncertain. Although a number of definitions of derivative can be found in the chemical literature, no single definition is adequate to describe all situations where it occurs in legislation. Unless qualified, it is suggested that the term derivative should be avoided in any future legislation. PMID:23949903

  4. 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

  5. [Chemical weapons and chemical terrorism].

    PubMed

    Nakamura, Katsumi

    2005-10-01

    Chemical Weapons are kind of Weapons of Mass Destruction (WMD). They were used large quantities in WWI. Historically, large quantities usage like WWI was not recorded, but small usage has appeared now and then. Chemical weapons are so called "Nuclear weapon for poor countrys" because it's very easy to produce/possession being possible. They are categorized (1) Nerve Agents, (2) Blister Agents, (3) Cyanide (blood) Agents, (4) Pulmonary Agents, (5) Incapacitating Agents (6) Tear Agents from the viewpoint of human body interaction. In 1997 the Chemical Weapons Convention has taken effect. It prohibits chemical weapons development/production, and Organization for the Prohibition of Chemical Weapons (OPCW) verification regime contributes to the chemical weapons disposal. But possibility of possession/use of weapons of mass destruction by terrorist group represented in one by Matsumoto and Tokyo Subway Sarin Attack, So new chemical terrorism countermeasures are necessary. PMID:16296384

  6. Chemical sensors

    DOEpatents

    Lowell, J.R. Jr.; Edlund, D.J.; Friesen, D.T.; Rayfield, G.W.

    1991-07-02

    Sensors responsive to small changes in the concentration of chemical species are disclosed. The sensors comprise a mechanochemically responsive polymeric film capable of expansion or contraction in response to a change in its chemical environment. They are operatively coupled to a transducer capable of directly converting the expansion or contraction to a measurable electrical response. 9 figures.

  7. Chemical preconcentrator

    DOEpatents

    Manginell, Ronald P. (Albuquerque, NM); Frye-Mason, Gregory C. (Cedar Crest, NM)

    2001-01-01

    A chemical preconcentrator is disclosed with applications to chemical sensing and analysis. The preconcentrator can be formed by depositing a resistive heating element (e.g. platinum) over a membrane (e.g. silicon nitride) suspended above a substrate. A coating of a sorptive material (e.g. a microporous hydrophobic sol-gel coating or a polymer coating) is formed on the suspended membrane proximate to the heating element to selective sorb one or more chemical species of interest over a time period, thereby concentrating the chemical species in the sorptive material. Upon heating the sorptive material with the resistive heating element, the sorbed chemical species are released for detection and analysis in a relatively high concentration and over a relatively short time period. The sorptive material can be made to selectively sorb particular chemical species of interest while not substantially sorbing other chemical species not of interest. The present invention has applications for use in forming high-sensitivity, rapid-response miniaturized chemical analysis systems (e.g. a "chem lab on a chip").

  8. 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)

  9. 40 CFR 721.6097 - Phosphoric acid derivative (generic name).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...2011-07-01 false Phosphoric acid derivative (generic name). 721.6097 Section...Substances § 721.6097 Phosphoric acid derivative (generic name). (a) Chemical...identified generically as a phosphoric acid derivative (PMN P-95-284) is subject...

  10. 40 CFR 721.6097 - Phosphoric acid derivative (generic name).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...2010-07-01 false Phosphoric acid derivative (generic name). 721.6097 Section...Substances § 721.6097 Phosphoric acid derivative (generic name). (a) Chemical...identified generically as a phosphoric acid derivative (PMN P-95-284) is subject...

  11. 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)

  12. Chemical Peels

    MedlinePLUS

    ... Bumps and growths Color problems Contagious skin diseases Cosmetic treatments Dry / sweaty skin Eczema / dermatitis Hair and ... dermatologist Home Public and patients Diseases and treatments Cosmetic treatments Chemical peels public SPOT Skin Cancer™ Diseases ...

  13. Chemical Agents

    MedlinePLUS

    ... Info Chemical Emergencies A–Z Abrin Adamsite Ammonia Arsenic Arsine Barium Benzene Brevetoxin Bromine BZ Carbon monoxide ... X Y Z A Abrin Adamsite (DM) Ammonia Arsenic Arsine (SA) B Barium Benzene Brevetoxin Bromine (CA) ...

  14. 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.

  15. Chemical sensors

    DOEpatents

    Lowell, J.R. Jr.; Edlund, D.J.; Friesen, D.T.; Rayfield, G.W.

    1992-06-09

    Sensors responsive to small changes in the concentration of chemical species are disclosed, comprising a mechanicochemically responsive polymeric film capable of expansion or contraction in response to a change in its chemical environment, either operatively coupled to a transducer capable of directly converting the expansion or contraction to a measurable electrical or optical response, or adhered to a second inert polymeric strip, or doped with a conductive material. 12 figs.

  16. 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...

  17. 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...

  18. 40 CFR 721.558 - Salt of a fatty alkylamine derivative (generic).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Salt of a fatty alkylamine derivative... Specific Chemical Substances § 721.558 Salt of a fatty alkylamine derivative (generic). (a) Chemical... as a salt of a fatty alkylamine derivative (PMN P-96-1426) is subject to reporting under this...

  19. 40 CFR 721.558 - Salt of a fatty alkylamine derivative (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Salt of a fatty alkylamine derivative... Specific Chemical Substances § 721.558 Salt of a fatty alkylamine derivative (generic). (a) Chemical... as a salt of a fatty alkylamine derivative (PMN P-96-1426) is subject to reporting under this...

  20. 40 CFR 721.558 - Salt of a fatty alkylamine derivative (generic).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Salt of a fatty alkylamine derivative... Specific Chemical Substances § 721.558 Salt of a fatty alkylamine derivative (generic). (a) Chemical... as a salt of a fatty alkylamine derivative (PMN P-96-1426) is subject to reporting under this...

  1. 40 CFR 721.558 - Salt of a fatty alkylamine derivative (generic).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Salt of a fatty alkylamine derivative... Specific Chemical Substances § 721.558 Salt of a fatty alkylamine derivative (generic). (a) Chemical... as a salt of a fatty alkylamine derivative (PMN P-96-1426) is subject to reporting under this...

  2. 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...

  3. 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...

  4. 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.

  5. 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.

  6. Chemical Modification of Polysaccharides

    PubMed Central

    Cumpstey, Ian

    2013-01-01

    This review covers methods for modifying the structures of polysaccharides. The introduction of hydrophobic, acidic, basic, or other functionality into polysaccharide structures can alter the properties of materials based on these substances. The development of chemical methods to achieve this aim is an ongoing area of research that is expected to become more important as the emphasis on using renewable starting materials and sustainable processes increases in the future. The methods covered in this review include ester and ether formation using saccharide oxygen nucleophiles, including enzymatic reactions and aspects of regioselectivity; the introduction of heteroatomic nucleophiles into polysaccharide chains; the oxidation of polysaccharides, including oxidative glycol cleavage, chemical oxidation of primary alcohols to carboxylic acids, and enzymatic oxidation of primary alcohols to aldehydes; reactions of uronic-acid-based polysaccharides; nucleophilic reactions of the amines of chitosan; and the formation of unsaturated polysaccharide derivatives. PMID:24151557

  7. Production of feedstock chemicals

    SciTech Connect

    Ng, T.K.; Busche, R.M.; McDonald, C.C.; Hardy, R.W.F.

    1983-02-11

    Renewable raw materials may be converted by biological means to feedstocks for the chemical industry. Glucose from cornstarch is the current choice as a substrate, although advances may enable the use of less expensive lignocellulosic materials. The production of oxychemicals and their derivatives from renewable resources could amount to about 100 billion pounds annually, or about half of the U.S. production of organic chemicals. Ethanol produced by fermentation is now cost-competitive with industrial ethanol produced from fossil fuel. Biological routes to other oxychemicals exist and are expected to be important in the future. Several product recovery methods may be used, but new energy-conserving methods will be needed to make the engineering-biology combinations economical. (Refs. 64).

  8. 40 CFR 180.1179 - Plant extract derived from Opuntia lindheimeri, Quercus falcata, Rhus aromatica, and Rhizophoria...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 2014-07-01 false Plant extract derived from Opuntia...PESTICIDE CHEMICAL RESIDUES IN FOOD Exemptions From Tolerances § 180.1179 Plant extract derived from Opuntia... The biochemical pesticide plant extract derived from...

  9. 40 CFR 180.1179 - Plant extract derived from Opuntia lindheimeri, Quercus falcata, Rhus aromatica, and Rhizophoria...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 2013-07-01 false Plant extract derived from Opuntia...PESTICIDE CHEMICAL RESIDUES IN FOOD Exemptions From Tolerances § 180.1179 Plant extract derived from Opuntia... The biochemical pesticide plant extract derived from...

  10. 40 CFR 180.1179 - Plant extract derived from Opuntia lindheimeri, Quercus falcata, Rhus aromatica, and Rhizophoria...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 2011-07-01 false Plant extract derived from Opuntia...PESTICIDE CHEMICAL RESIDUES IN FOOD Exemptions From Tolerances § 180.1179 Plant extract derived from Opuntia... The biochemical pesticide plant extract derived from...

  11. 40 CFR 180.1179 - Plant extract derived from Opuntia lindheimeri, Quercus falcata, Rhus aromatica, and Rhizophoria...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 2012-07-01 false Plant extract derived from Opuntia...PESTICIDE CHEMICAL RESIDUES IN FOOD Exemptions From Tolerances § 180.1179 Plant extract derived from Opuntia... The biochemical pesticide plant extract derived from...

  12. 40 CFR 721.1300 - [(Dinitrophenyl)azo]-[2,4-dia-mino-5-methoxybenzene] derivatives.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...4-dia-mino-5-methoxybenzene] derivatives. 721.1300 Section 721.1300...4-dia-mino-5-methoxybenzene] derivatives. (a) Chemical substances and significant...4-di-a-mino-5-methoxybenzene] derivatives (P-83-817 and...

  13. 40 CFR 721.1825 - Bisphenol A, epichloro-hy-drin, polyalkylenepolyol and poly-iso-cyanato derivative.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...polyalkylenepolyol and poly-iso-cyanato derivative. 721.1825 Section 721.1825...polyalkylenepolyol and poly-iso-cyanato derivative. (a) Chemical substance and significant...polyalkylenepolyol and polyisocyanato derivative (PMN P-89-750) is subject...

  14. 40 CFR 721.1825 - Bisphenol A, epichloro-hy-drin, polyalkylenepolyol and poly-iso-cyanato derivative.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...polyalkylenepolyol and poly-iso-cyanato derivative. 721.1825 Section 721.1825...polyalkylenepolyol and poly-iso-cyanato derivative. (a) Chemical substance and significant...polyalkylenepolyol and polyisocyanato derivative (PMN P-89-750) is subject...

  15. 40 CFR 721.1300 - [(Dinitrophenyl)azo]-[2,4-dia-mino-5-methoxybenzene] derivatives.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...4-dia-mino-5-methoxybenzene] derivatives. 721.1300 Section 721.1300...4-dia-mino-5-methoxybenzene] derivatives. (a) Chemical substances and significant...4-di-a-mino-5-methoxybenzene] derivatives (P-83-817 and...

  16. Introduction Derivative Expansion

    E-print Network

    Introduction Derivative Expansion Examples Generalization: Higher dimensions + thermal effects Electromagnetic field and imperfect mirrors Conclusions A Derivative Expansion for the Casimir Effect C. D. Fosco1-10-2012 C. D. Fosco. In collaboration with: F. D. Lombardo and F. D. Mazzitelli Derivative Expansion #12

  17. Delicious Chemicals.

    ERIC Educational Resources Information Center

    Barry, Dana M.

    This paper presents an approach to chemistry and nutrition that focuses on food items that people consider delicious. Information is organized according to three categories of food chemicals that provide energy to the human body: (1) fats and oils; (2) carbohydrates; and (3) proteins. Minerals, vitamins, and additives are also discussed along with…

  18. 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…

  19. 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 not derive from a direct coupling of the acoustic field with chemical species on a molecular level. Instead

  20. Absolute Time Derivatives

    E-print Network

    T. Matolcsi; P. Van

    2006-10-23

    A four dimensional treatment of nonrelativistic space-time gives a natural frame to deal with objective time derivatives. In this framework some well known objective time derivatives of continuum mechanics appear as Lie-derivatives. Their coordinatized forms depends on the tensorial properties of the relevant physical quantities. We calculate the particular forms of objective time derivatives for scalars, vectors, covectors and different second order tensors from the point of view of a rotating observer. The relation of substantial, material and objective time derivatives is treated.

  1. Generalized \\delta-Derivations

    E-print Network

    Kaygorodov, Ivan

    2011-01-01

    We defined generalized \\delta-derivations of algebra A as linear mapping \\chi associated with usual \\delta-derivation \\phi by the rule \\chi(xy)=\\delta(\\chi(x)y+x\\phi(y))=\\delta(\\phi(x)y+x\\chi(y)) for any x,y \\in A. We described generalized \\delta-derivations of prime alternative algebras, prime Lie algebras and superalgebras, unital algebras, and semisimple finite-dimensional Jordan superalgebras. In this cases we proved that generalized \\delta-derivation is a generalized derivation or \\delta-derivation. After that we described \\delta-superderivations of superalgebras >, arising from prime alternative algebras, prime Lie algebras and superalgebras, unital algebras, and semisimple finite-dimensional Jordan superalgebras. In the end, we constructed new examples of non-trivial \\delta-derivations of Lie algebras.

  2. 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

  3. Synthesis of pyroglutamic acid derivatives via double Michael addition reactions of alkynones. 

    E-print Network

    Scansetti, Myriam

    2009-01-01

    I. Synthesis of pyroglutamic acid derivatives via double Michael reactions of alkynones Pyroglutamic acids and their derivatives are common structural units of widespread chemical significance and they have been heavily ...

  4. 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.

  5. 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 ...

  6. 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.

  7. 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 ,...

  8. 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 ,...

  9. 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 ,...

  10. 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 189.120 Food and Drugs FOOD...Use as Human Food § 189.120 Cobaltous salts and its derivatives. (a) Cobaltous salts are the chemicals, CoC4 H6...

  11. 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 189.120 Food and Drugs FOOD...Use as Human Food § 189.120 Cobaltous salts and its derivatives. (a) Cobaltous salts are the chemicals, CoC4 H6...

  12. 40 CFR 721.646 - Aminofluoran derivative (generic name).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Aminofluoran derivative (generic name). 721.646 Section 721.646 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC... Substances § 721.646 Aminofluoran derivative (generic name). (a) Chemical substance and significant new...

  13. 40 CFR 721.646 - Aminofluoran derivative (generic name).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Aminofluoran derivative (generic name). 721.646 Section 721.646 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC... Substances § 721.646 Aminofluoran derivative (generic name). (a) Chemical substance and significant new...

  14. 40 CFR 721.646 - Aminofluoran derivative (generic name).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Aminofluoran derivative (generic name). 721.646 Section 721.646 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC... Substances § 721.646 Aminofluoran derivative (generic name). (a) Chemical substance and significant new...

  15. 40 CFR 721.646 - Aminofluoran derivative (generic name).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Aminofluoran derivative (generic name). 721.646 Section 721.646 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC... Substances § 721.646 Aminofluoran derivative (generic name). (a) Chemical substance and significant new...

  16. 40 CFR 721.646 - Aminofluoran derivative (generic name).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Aminofluoran derivative (generic name). 721.646 Section 721.646 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC... Substances § 721.646 Aminofluoran derivative (generic name). (a) Chemical substance and significant new...

  17. Azaphilone and Diphenyl Ether Derivatives from a Gorgonian-Derived Strain of the Fungus Penicillium pinophilum.

    PubMed

    Zhao, Dong-Lin; Shao, Chang-Lun; Zhang, Qiang; Wang, Kai-Ling; Guan, Fei-Fei; Shi, Ting; Wang, Chang-Yun

    2015-09-25

    Three new azaphilone derivatives, pinophilins D-F (1-3), and one new diphenyl ether derivative, hydroxypenicillide (10), together with nine known compounds (4-9, 11-13), were isolated from the gorgonian-derived fungus Penicillium pinophilum XS-20090E18. Their structures including absolute configurations were determined by spectroscopic data, chemical conversions, the ECD exciton chirality method, and ECD calculations. Compounds 10-13 exhibited inhibitory activity against the larval settlement of the barnacle Balanus amphitrite at nontoxic concentrations. Compounds 10 and 11 showed cytotoxicity against Hep-2, RD, and HeLa cell lines. PMID:26291474

  18. Distillation of natural fatty acids and their chemical derivatives

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Well over 1,000 different fatty acids are known which are natural components of fats, oils (triacylglycerols), and other related compounds. These fatty acids can have different alkyl chain lengths, 0-6 carbon-carbon double bonds possessing cis- or trans-geometry, and can contain a variety of functio...

  19. Chemical and photochemical properties of chloroharmine derivatives in aqueous solutions.

    PubMed

    Rasse-Suriani, Federico A O; Paula Denofrio, M; Yañuk, Juan G; Micaela Gonzalez, M; Wolcan, Ezequiel; Seifermann, Marco; Erra-Balsells, Rosa; Cabrerizo, Franco M

    2015-12-23

    Thermal and photochemical stability (?R), room temperature UV-vis absorption and fluorescence spectra, fluorescence quantum yields (?F) and lifetimes (?F), quantum yields of hydrogen peroxide (?H2O2) and singlet oxygen (??) production, and triplet lifetimes (?T) have been obtained for the neutral and protonated forms of 6-chloroharmine, 8-chloroharmine and 6,8-dichloroharmine, in aqueous media. When it was possible, the effect of pH and oxygen concentration was evaluated. The nature of electronic transitions of protonated and neutral species of the three investigated chloroharmines was established using Time-Dependent Density Functional Theory (TD-DFT) calculations. The impact of all the foregoing observations on the biological role of the studied compounds is discussed. PMID:26648161

  20. 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...

  1. Pyrazine-Derived Disulfide-Reducing Agent for Chemical Biology

    PubMed Central

    Lukesh, John C.; Wallin, Kelly K.

    2014-01-01

    For fifty years, dithiothreitol (DTT) has been the preferred reagent for the reduction of disulfide bonds in proteins and other biomolecules. Herein we report on the synthesis and characterization of 2,3-bis(mercaptomethyl)pyrazine (BMMP), a readily accessible disulfide-reducing agent with reactivity under biological conditions that is markedly superior to DTT and other known reagents. PMID:25014913

  2. 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

  3. The kinetic chemical equilibrium regime

    NASA Astrophysics Data System (ADS)

    Ern, Alexandre; Giovangigli, Vincent

    We investigate reactive gas mixtures in the kinetic chemical equilibrium regime. Our starting point is a generalized Boltzmann equation with a chemical source term valid for arbitrary reaction mechanisms and yielding a positive entropy production. We first study the Enskog expansion in the kinetic chemical equilibrium regime. We derive a new set of macroscopic equations in the zeroth- and first-order regimes, expressing conservation of element densities, momentum and energy. The transport fluxes arising in the Navier-Stokes equilibrium regime are the element diffusion velocities, the heat flux vector and the pressure tensor and are written in terms of transport coefficients. Upon introducing species diffusion velocities, the kinetic equilibrium regime appears to be formally equivalent to the one obtained for gas mixtures in chemical nonequilibrium and then letting the chemical reactions approach equilibrium. The actual values of the transport coefficients are, however, different. Finally, we derive the entropy conservation equation in the Navier-Stokes equilibrium regime and show that the source term is positive and that it is compatible with Onsager’s reciprocal relations.

  4. Chemical durability

    SciTech Connect

    Kreuer, K.D.; Warhus, U.

    1986-03-01

    The chemical durability of NASICON (Na/sub 1+x/Zr/sub 2/Si/sub x/P/sub 3-x/O/sub 12/, x=0-3) versus molten sodium and sulfur at 600 K has been investigated. Degradation by molten sodium has been observed for phosphorus-containing compositions only. The pure silicate (x=3), however, appeared to be stable, because reduction of silicon demanded by thermodynamics did not occur at the given temperature for kinetic reasons. The latter composition has also been shown to have good durability against molten sulfur.

  5. The Derivation of Primary Human Epicardium-Derived Cells.

    PubMed

    Clunie-O'Connor, Caitlin; Smits, Anke M; Antoniades, Charalambos; Russell, Angela J; Yellon, Derek M; Goumans, Marie-José; Riley, Paul R

    2015-01-01

    To develop therapeutic strategies for the regeneration of lost heart muscle after myocardial infarction (MI), a source of functional new muscle cells and associated coronary vessels must be identified. The epicardium is a source of several cardiovascular cell types during heart development and is widely regarded as a resident progenitor population, which becomes dormant during adulthood. In adult mice, MI induces epicardial reactivation characterized by an upregulation of fetal genes and subsequent epicardium derived cell (EPDC) proliferation, migration, and differentiation. Determining whether the epicardium can be therapeutically targeted following cardiovascular disease requires an in vitro system for the study of adult human EPDCs (hEPDCs). This protocol describes techniques to establish and maintain human epicardium explant cultures from patient-derived right atrial appendage biopsies and documents methods to probe the resultant outgrowth of hEPDCs. The model facilitates a high-throughput approach to either genetic or chemical phenotypic screening for drug-like modifiers of hEPDC activation and potential cell fate. © 2015 by John Wiley & Sons, Inc. PMID:26544538

  6. 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

  7. PROOF COPY 705507JCP Stochastic chemical reactions in microdomains

    E-print Network

    Holcman, David

    PROOF COPY 705507JCP PROOF COPY 705507JCP Stochastic chemical reactions in microdomains D. Holcman; accepted 24 November 2004 Traditional chemical kinetics may be inappropriate to describe chemical reactions dynamics of the molecules, we derive a master-diffusion equation for the joint probability density

  8. 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

  9. Chemical Engineering Rate Processes

    E-print Network

    Fenster, Sam

    Chemical Engineering · Rate Processes Physical Chemical Biochemical · Example - pharmacokinetics ocw.mit.edu #12;The historical chemical engineer · Chemistry + Mechanical design of equipment chemical engineer today · Electronics · Pharmaceuticals · Environment - Air, Energy and Water

  10. 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.

  11. Mixtures are not derivable

    NASA Astrophysics Data System (ADS)

    Alsina, C.; Schweizer, B.

    1988-06-01

    A binary operation ø on probability distribution functions is derivable from a binary operation on random variables if there exists a two-place function V such that, for any distribution functions F and G, there exist random variables X and Y, defined on a common probability space, such that F and G are the distribution functions of X and Y , respectively, and ø( F, G) is the distribution function of V ( X, Y). We show that if ø( F, G) = cF + (1 - c) G, 0 < c < 1, then ø is not derivable; similarly,? (F,G) = sqrt {FG} is not derivable.

  12. Chemical Accelerators The phrase "chemical accelerators"

    E-print Network

    Meetings Chemical Accelerators The phrase "chemical accelerators" is scarcely older than for one or two dozen people grew to include nearly a hundred. Chemical accelerators is a name sug- gested by one of us for devices that produce beams of chemically interesting species at relative kinetic

  13. Credit derivatives in Brazil

    E-print Network

    Rüther, Henrique

    2007-01-01

    The amounts outstanding of credit derivatives have grown exponentially over the past years, and these financial intruments that allow market participants to trade credit risk have become very popular in Europe and in the ...

  14. 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 ...

  15. The azobenzene derivatives

    NASA Astrophysics Data System (ADS)

    Ionita, Ionica; Radulescu, Cristiana; Poinescu, Aurora Anca; Anghelina, Florina Violeta; Bunghez, Raluca; Ion, Rodica-Mariana

    2015-02-01

    Azobenzene derivatives constitute a group of dyes which have photochromic properties and have been investigated as promising systems for diverse applications in the unconventional optic area, their properties can be moulded with help of light.

  16. 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

  17. 40 CFR 721.558 - Salt of a fatty alkylamine derivative (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Salt of a fatty alkylamine derivative... Specific Chemical Substances § 721.558 Salt of a fatty alkylamine derivative (generic). Link to an... to reporting. (1) The chemical substance identified generically as a salt of a fatty...

  18. 40 CFR 721.430 - Oxo-substituted amino-al-kanoic acid derivative.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Oxo-substituted amino-al-kanoic acid... Specific Chemical Substances § 721.430 Oxo-substituted amino-al-kanoic acid derivative. (a) Chemical... as oxo-substituted amino al-kan-oic acid derivative (PMN No. P-92-692) is subject to reporting...

  19. 40 CFR 721.430 - Oxo-substituted amino-al-kanoic acid derivative.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Oxo-substituted amino-al-kanoic acid... Specific Chemical Substances § 721.430 Oxo-substituted amino-al-kanoic acid derivative. (a) Chemical... as oxo-substituted amino al-kan-oic acid derivative (PMN No. P-92-692) is subject to reporting...

  20. 40 CFR 721.430 - Oxo-substituted amino-al-kanoic acid derivative.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Oxo-substituted amino-al-kanoic acid... Specific Chemical Substances § 721.430 Oxo-substituted amino-al-kanoic acid derivative. (a) Chemical... as oxo-substituted amino al-kan-oic acid derivative (PMN No. P-92-692) is subject to reporting...

  1. 40 CFR 721.430 - Oxo-substituted amino-al-kanoic acid derivative.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Oxo-substituted amino-al-kanoic acid... Specific Chemical Substances § 721.430 Oxo-substituted amino-al-kanoic acid derivative. (a) Chemical... as oxo-substituted amino al-kan-oic acid derivative (PMN No. P-92-692) is subject to reporting...

  2. 40 CFR 721.430 - Oxo-substituted amino-al-kanoic acid derivative.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Oxo-substituted amino-al-kanoic acid... Specific Chemical Substances § 721.430 Oxo-substituted amino-al-kanoic acid derivative. (a) Chemical... as oxo-substituted amino al-kan-oic acid derivative (PMN No. P-92-692) is subject to reporting...

  3. 40 CFR 721.5358 - 2-propanol, 1,1?,1?-nitrilotris-, compds. with ethanol 2-[2-(C12-14- alkyloxy) ethoxy] derivs...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...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;...

  4. 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;...

  5. 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

  6. [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

  7. 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.

  8. Exposure Levels for Chemical Threat Compounds; Information to Facilitate Chemical Incident Response

    SciTech Connect

    Hauschild, Veronique; Watson, Annetta Paule

    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.

  9. 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...

  10. CHEMICAL ENGINEERING Curriculum Notes

    E-print Network

    Mohan, Chilukuri K.

    CHEMICAL ENGINEERING Curriculum Notes 2013-2014 1. Chemical engineering students must complete not included in the required chemical engineering curriculum. All technical electives are subject to approval be in chemical engineering. 2. Chemical engineering students must complete a minimum of 18 credits in the Social

  11. Chemical Ecology: Chemical Communication in Nature.

    ERIC Educational Resources Information Center

    Wood, William F.

    1983-01-01

    Substances that deliver chemical messages between same/different species are called semiochemicals. Surveyed are three types of semiochemicals (pheromones, allomones, and kairomones), types of organisms involved, and specific chemicals used to carry the various kinds of messages. (JN)

  12. 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.

  13. Telomeric 30 Overhangs Derive

    E-print Network

    de Lange, Titia

    Telomeric 30 Overhangs Derive from Resection by Exo1 and Apollo and Fill-In by POT1b-Associated CST and main- tenance of mammalian telomeres, but its synthesis must be regulated to avoid excessive resection of the 50 end, which could cause telomere shortening. How this balance is achieved in mammals has not been

  14. 78 FR 32191 - Derivatives

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-29

    ... alternatives. \\5\\ 71 FR 5155 (February 2, 2012). C. 1998 IRPS This proposed rule is consistent with a 1998... promulgation of this proposed rule. \\7\\ 76 FR 37030 (June 24, 2011). First, the Board asked if it should... derivatives transactions independently. \\9\\ 77 FR 5416 (Feb. 3, 2012). Question One. The Board asked if...

  15. 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), ...

  16. 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)

  17. 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.

  18. Explanatory document related to the paper entitled "Signal Processing Applied to Chemically Inspired

    E-print Network

    Vetter, Thomas

    REGARDING THE DERIVATION OF THE TRANSFER FUNCTION (TF) OF THE CHEMICAL CONGESTION CONTROL ALGORITHM (C3A vloss2 (b) The chemical reaction network of C3A Fig. 1: A general model of two packet streams sharing the same channel (a), and the chemical reaction network of C3A that implements the chemical congestion

  19. 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

  20. Microfluidic chemical reaction circuits

    DOEpatents

    Lee, Chung-cheng (Irvine, CA); Sui, Guodong (Los Angeles, CA); Elizarov, Arkadij (Valley Village, CA); Kolb, Hartmuth C. (Playa del Rey, CA); Huang, Jiang (San Jose, CA); Heath, James R. (South Pasadena, CA); Phelps, Michael E. (Los Angeles, CA); Quake, Stephen R. (Stanford, CA); Tseng, Hsian-rong (Los Angeles, CA); Wyatt, Paul (Tipperary, IE); Daridon, Antoine (Mont-Sur-Rolle, CH)

    2012-06-26

    New microfluidic devices, useful for carrying out chemical reactions, are provided. The devices are adapted for on-chip solvent exchange, chemical processes requiring multiple chemical reactions, and rapid concentration of reagents.

  1. 40 CFR 721.1675 - Disulfonic acid rosin amine salt of a benzidine derivative (generic name).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...acid rosin amine salt of a benzidine derivative (generic name). 721.1675 Section...acid rosin amine salt of a benzidine derivative (generic name). (a) Chemical...acid rosin amine salt of a benzidine derivative (PMN P-87-1337) is subject...

  2. 40 CFR 721.1240 - Benzene, (2-bromoethyl)-, ar-bromo derivatives.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...Benzene, (2-bromoethyl)-, ar-bromo derivatives. 721.1240 Section 721.1240...Benzene, (2-bromoethyl)-, ar-bromo derivatives. (a) Chemical substance and significant...benzene, (2-bromoethyl)-, ar-bromo derivatives (PMN P-84-704; CAS No....

  3. 40 CFR 721.1240 - Benzene, (2-bromoethyl)-, ar-bromo derivatives.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...Benzene, (2-bromoethyl)-, ar-bromo derivatives. 721.1240 Section 721.1240...Benzene, (2-bromoethyl)-, ar-bromo derivatives. (a) Chemical substance and significant...benzene, (2-bromoethyl)-, ar-bromo derivatives (PMN P-84-704; CAS No....

  4. 40 CFR 721.1230 - Benzene, ethenyl-, ar-bromo derivatives.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...false Benzene, ethenyl-, ar-bromo derivatives. 721.1230 Section 721.1230...1230 Benzene, ethenyl-, ar-bromo derivatives. (a) Chemical substance and significant...identified as benzene, ethenyl-, ar-bromo derivatives (PMN P-84-660; CAS...

  5. 40 CFR 721.4520 - Isopropylidene, bis(1,1-dimethylpropyl) derivative.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...Isopropylidene, bis(1,1-dimethylpropyl) derivative. 721.4520 Section 721.4520...Isopropylidene, bis(1,1-dimethylpropyl) derivative. (a) Chemical substance and significant...isopropylidene, bis(1,1-dimethylpropyl) derivative (PMN P-85-648) is subject...

  6. 40 CFR 721.558 - Salt of a fatty alkylamine derivative (generic).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... false Salt of a fatty alkylamine derivative (generic). 721.558 Section...721.558 Salt of a fatty alkylamine derivative (generic). (a) Chemical substance...generically as a salt of a fatty alkylamine derivative (PMN P-96-1426) is subject...

  7. 40 CFR 721.1230 - Benzene, ethenyl-, ar-bromo derivatives.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...false Benzene, ethenyl-, ar-bromo derivatives. 721.1230 Section 721.1230...1230 Benzene, ethenyl-, ar-bromo derivatives. (a) Chemical substance and significant...identified as benzene, ethenyl-, ar-bromo derivatives (PMN P-84-660; CAS...

  8. 40 CFR 721.1675 - Disulfonic acid rosin amine salt of a benzidine derivative (generic name).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...acid rosin amine salt of a benzidine derivative (generic name). 721.1675 Section...acid rosin amine salt of a benzidine derivative (generic name). (a) Chemical...acid rosin amine salt of a benzidine derivative (PMN P-87-1337) is subject...

  9. 40 CFR 721.4520 - Isopropylidene, bis(1,1-dimethylpropyl) derivative.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...Isopropylidene, bis(1,1-dimethylpropyl) derivative. 721.4520 Section 721.4520...Isopropylidene, bis(1,1-dimethylpropyl) derivative. (a) Chemical substance and significant...isopropylidene, bis(1,1-dimethylpropyl) derivative (PMN P-85-648) is subject...

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

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... false Salt of a fatty alkylamine derivative (generic). 721.558 Section...721.558 Salt of a fatty alkylamine derivative (generic). (a) Chemical substance...generically as a salt of a fatty alkylamine derivative (PMN P-96-1426) is subject...

  11. 40 CFR 721.10045 - Diazotized substituted heteromonocycle coupled with naphthalene sulfonic acid derivative, nickel...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... coupled with naphthalene sulfonic acid derivative, nickel complex, alkaline salt (generic). 721.10045... derivative, nickel complex, alkaline salt (generic). (a) Chemical substance and significant new uses subject... heteromonocycle coupled with naphthalene sulfonic acid derivative, nickel complex, alkaline salt (PMN P-02-737)...

  12. 40 CFR 721.10045 - Diazotized substituted heteromonocycle coupled with naphthalene sulfonic acid derivative, nickel...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... coupled with naphthalene sulfonic acid derivative, nickel complex, alkaline salt (generic). 721.10045... derivative, nickel complex, alkaline salt (generic). (a) Chemical substance and significant new uses subject... heteromonocycle coupled with naphthalene sulfonic acid derivative, nickel complex, alkaline salt (PMN P-02-737)...

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

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... coupled with naphthalene sulfonic acid derivative, nickel complex, alkaline salt (generic). 721.10045... derivative, nickel complex, alkaline salt (generic). (a) Chemical substance and significant new uses subject... heteromonocycle coupled with naphthalene sulfonic acid derivative, nickel complex, alkaline salt (PMN P-02-737)...

  14. 40 CFR 721.10045 - Diazotized substituted heteromonocycle coupled with naphthalene sulfonic acid derivative, nickel...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... coupled with naphthalene sulfonic acid derivative, nickel complex, alkaline salt (generic). 721.10045... derivative, nickel complex, alkaline salt (generic). (a) Chemical substance and significant new uses subject... heteromonocycle coupled with naphthalene sulfonic acid derivative, nickel complex, alkaline salt (PMN P-02-737)...

  15. 40 CFR 721.10045 - Diazotized substituted heteromonocycle coupled with naphthalene sulfonic acid derivative, nickel...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... coupled with naphthalene sulfonic acid derivative, nickel complex, alkaline salt (generic). 721.10045... derivative, nickel complex, alkaline salt (generic). (a) Chemical substance and significant new uses subject... heteromonocycle coupled with naphthalene sulfonic acid derivative, nickel complex, alkaline salt (PMN P-02-737)...

  16. Chemical Management System

    Energy Science and Technology Software Center (ESTSC)

    1998-10-30

    CMS provides an inventory of all chemicals on order or being held in the laboratory, to provide a specific location for all chemical containers, to ensure that health and safety regulatory codes are being upheld, and to provide PNNL staff with hazardous chemical information to better manage their inventories. CMS is comprised of five major modules: 1) chemical purchasing, 2) chemical inventory, 3) chemical names, properties, and hazard groups, 4) reporting, and 5) system administration.

  17. Nature's chemicals and synthetic chemicals: Comparative toxicology

    SciTech Connect

    Ames, B.N.; Profet, M.; Gold, L.S. )

    1990-10-01

    The toxicology of synthetic chemicals is compared to that of natural chemicals, which represent the vast bulk of the chemicals to which humans are exposed. It is argued that animals have a broad array of inducible general defenses to combat the changing array of toxic chemicals in plant food (nature's pesticides) and that these defenses are effective against both natural and synthetic toxins. Synthetic toxins such as dioxin are compared to natural chemicals, such as indole carbinol (in broccoli) and ethanol. Trade-offs between synthetic and natural pesticides are discussed. The finding that in high-dose tests, a high proportion of both natural and synthetic chemicals are carcinogens, mutagens, teratogens, and clastogens (30-50{percent} for each group) undermines current regulatory efforts to protect public health from synthetic chemicals based on these tests.

  18. Satellite-Derived Management Zones

    NASA Technical Reports Server (NTRS)

    Lepoutre, Damien; Layrol, Laurent

    2005-01-01

    The term "satellite-derived management zones" (SAMZ) denotes agricultural management zones that are subdivisions of large fields and that are derived from images of the fields acquired by instruments aboard Earth-orbiting satellites during approximately the past 15 years. "SAMZ" also denotes the methodology and the software that implements the methodology for creating such zones. The SAMZ approach is one of several products of continuing efforts to realize a concept of precision agriculture, which involves optimal variations in seeding, in application of chemicals, and in irrigation, plus decisions to farm or not to farm certain portions of fields, all in an effort to maximize profitability in view of spatial and temporal variations in the growth and health of crops, and in the chemical and physical conditions of soils. As used here, "management zone" signifies, more precisely, a subdivision of a field within which the crop-production behavior is regarded as homogeneous. From the perspective of precision agriculture, management zones are the smallest subdivisions between which the seeding, application of chemicals, and other management parameters are to be varied. In the SAMZ approach, the main sources of data are the archives of satellite imagery that have been collected over the years for diverse purposes. One of the main advantages afforded by the SAMZ approach is that the data in these archives can be reused for purposes of precision agriculture at low cost. De facto, these archives contain information on all sources of variability within a field, including weather, crop types, crop management, soil types, and water drainage patterns. The SAMZ methodology involves the establishment of a Web-based interface based on an algorithm that generates management zones automatically and quickly from archival satellite image data in response to requests from farmers. A farmer can make a request by either uploading data describing a field boundary to the Web site or else drawing the boundary on a reference image. Hence, a farmer can start to engage in precision farming shortly after gaining access to the Web site, without the need for incurring the high costs of conventional precision-agriculture data-collection practices that include collecting soil samples, mapping electrical conductivity of soil, and compiling multiyear crop-yield data. Given the boundary of a field, a SAMZ server computes the zones within the field in a three-stage process. In the first stage, a vector-valued image of the field is constructed by assembling, from the archives, the equivalent of a stack of the available images of the field (see figure). In the second stage, the vector-valued image is analyzed by use of a wavelet transform that detects spatial variations considered significant for precision farming while suppressing small-scale heterogeneities that are regarded as insignificant. In the third stage, a segmentation algorithm assembles the zones from smaller regions that have been identified in the wavelet analysis.

  19. Insulin-derived amyloidosis

    PubMed Central

    Gupta, Yashdeep; Singla, Gaurav; Singla, Rajiv

    2015-01-01

    Amyloidosis is the term for diseases caused by the extracellular deposition of insoluble polymeric protein fibrils in tissues and organs. Insulin-derived amyloidosis is a rare, yet significant complication of insulin therapy. Insulin-derived amyloidosis at injection site can cause poor glycemic control and increased insulin dose requirements because of the impairment in insulin absorption, which reverse on change of injection site and/or excision of the mass. This entity should be considered and assessed by histopathology and immunohistochemistry, in patients with firm/hard local site reactions, which do not regress after cessation of insulin injection at the affected site. Search strategy: PubMed was searched with terms “insulin amyloidosis”. Full text of articles available in English was reviewed. Relevant cross references were also reviewed. Last search was made on October 15, 2014. PMID:25593849

  20. Derived enriched uranium market

    SciTech Connect

    Rutkowski, E.

    1996-12-01

    The potential impact on the uranium market of highly enriched uranium from nuclear weapons dismantling in the Russian Federation and the USA is analyzed. Uranium supply, conversion, and enrichment factors are outlined for each country; inventories are also listed. The enrichment component and conversion components are expected to cause little disruption to uranium markets. The uranium component of Russian derived enriched uranium hexafluoride is unresolved; US legislation places constraints on its introduction into the US market.

  1. 21 CFR 189.120 - Cobaltous salts and its derivatives.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Cobaltous salts and its derivatives. 189.120... Generally Prohibited From Direct Addition or Use as Human Food § 189.120 Cobaltous salts and its derivatives. (a) Cobaltous salts are the chemicals, CoC4H6O4, CoCl2, and CoSO4.They have been used in...

  2. 21 CFR 189.120 - Cobaltous salts and its derivatives.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Cobaltous salts and its derivatives. 189.120... Generally Prohibited From Direct Addition or Use as Human Food § 189.120 Cobaltous salts and its derivatives. (a) Cobaltous salts are the chemicals, CoC4H6O4, CoCl2, and CoSO4.They have been used in...

  3. 21 CFR 189.120 - Cobaltous salts and its derivatives.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Cobaltous salts and its derivatives. 189.120... Generally Prohibited From Direct Addition or Use as Human Food § 189.120 Cobaltous salts and its derivatives. (a) Cobaltous salts are the chemicals, CoC4H6O4, CoCl2, and CoSO4.They have been used in...

  4. 21 CFR 189.120 - Cobaltous salts and its derivatives.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Cobaltous salts and its derivatives. 189.120... Generally Prohibited From Direct Addition or Use as Human Food § 189.120 Cobaltous salts and its derivatives. (a) Cobaltous salts are the chemicals, CoC4H6O4, CoCl2, and CoSO4.They have been used in...

  5. Treatment of biomass to obtain a target chemical

    DOEpatents

    Dunson, Jr., James B. (Newark, DE); Tucker, III, Melvin P. (Lakewood, CO); Elander, Richard T. (Evergreen, CO); Hennessey, Susan Marie (Avondale, PA)

    2010-08-24

    Target chemicals were produced using biocatalysts that are able to ferment sugars derived from treated biomass. Sugars were obtained by pretreating biomass under conditions of high solids and low ammonia concentration, followed by saccharification.

  6. Olefin recovery via chemical absorption

    SciTech Connect

    Barchas, R.

    1998-06-01

    The recovery of fight olefins in petrochemical plants has generally been accomplished through cryogenic distillation, a process which is very capital and energy intensive. In an effort to simplify the recovery process and reduce its cost, BP Chemicals has developed a chemical absorption technology based on an aqueous silver nitrate solution. Stone & Webster is now marketing, licensing, and engineering the technology. The process is commercially ready for recovering olefins from olefin derivative plant vent gases, such as vents from polyethylene, polypropylene, ethylene oxide, and synthetic ethanol units. The process can also be used to debottleneck C{sub 2} or C{sub 3} splinters, or to improve olefin product purity. This paper presents the olefin recovery imp technology, discusses its applications, and presents economics for the recovery of ethylene and propylene.

  7. Balancing Equations Chemical Reactions

    E-print Network

    Heller, Barbara

    Balancing Equations Chemical Reactions #12;Chemical Equations · A chemical equation describes what of the participants (solid, liquid, gas, aqueous) and the amount of each substance. #12;Balancing of Equations · To balance a chemical equation, you have to establish a mathematical relationship between the quantity

  8. Chemical Emergencies Overview

    MedlinePLUS

    ... that cause nausea and vomiting Hazardous chemicals by name (A-Z list) If you know the name of a chemical but aren’t sure what ... in, you can look for the chemical by name on the A–Z List of Chemical Agents . ...

  9. Enveloped virus inactivation by fatty acid derivatives.

    PubMed

    Sands, J A; Auperin, L D; Reinhardt, A

    1979-01-01

    The enveloped bacteriophage phi6 has been shown to be a valuable model system for the preliminary screening of compounds that might be expected to inactivate herpes simplex virus and other enveloped mammalian viruses. A variety of fatty acid derivatives that form fluid micelles in aqueous media have been found to be potent inactivators of phi6. The chemical nature of the polar head group, the length of the alkyl chain(s), and the extent and geometry of unsaturation are all important parameters in determining the antiviral effectiveness of this class of compounds. PMID:218498

  10. Lignin-Derived Advanced Carbon Materials.

    PubMed

    Chatterjee, Sabornie; Saito, Tomonori

    2015-12-01

    Lignin is a highly abundant source of renewable carbon that can be considered as a valuable sustainable source of biobased materials. By applying specific pretreatments and manufacturing methods, lignin can be converted into a variety of value-added carbon materials. However, the physical and chemical heterogeneities of lignin complicate its use as a feedstock. Herein lignin manufacturing process, the effects of pretreatments and manufacturing methods on the properties of product lignin, and structure-property relationships in various applications of lignin-derived carbon materials, such as carbon fibers, carbon mats, activated carbons, carbon films, and templated carbon, are discussed. PMID:26568373

  11. Revisiting the definition of the electronic chemical potential, chemical hardness, and softness at finite temperatures.

    PubMed

    Franco-Pérez, Marco; Gázquez, José L; Ayers, Paul W; Vela, Alberto

    2015-10-21

    We extend the definition of the electronic chemical potential (?e) and chemical hardness (?e) to finite temperatures by considering a reactive chemical species as a true open system to the exchange of electrons, working exclusively within the framework of the grand canonical ensemble. As in the zero temperature derivation of these descriptors, the response of a chemical reagent to electron-transfer is determined by the response of the (average) electronic energy of the system, and not by intrinsic thermodynamic properties like the chemical potential of the electron-reservoir which is, in general, different from the electronic chemical potential, ?e. Although the dependence of the electronic energy on electron number qualitatively resembles the piecewise-continuous straight-line profile for low electronic temperatures (up to ca. 5000 K), the introduction of the temperature as a free variable smoothens this profile, so that derivatives (of all orders) of the average electronic energy with respect to the average electron number exist and can be evaluated analytically. Assuming a three-state ensemble, well-known results for the electronic chemical potential at negative (-I), positive (-A), and zero values of the fractional charge (-(I + A)/2) are recovered. Similarly, in the zero temperature limit, the chemical hardness is formally expressed as a Dirac delta function in the particle number and satisfies the well-known reciprocity relation with the global softness. PMID:26493893

  12. 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.

  13. 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.

  14. Research projects for 2014 Natural Products Chemistry / Sustainable Chemicals for the Future Prof. Chris Rayner Prof. Chris Rayner

    E-print Network

    Rzepa, Henry S.

    Research projects for 2014 ­ Natural Products Chemistry / Sustainable Chemicals for the Future Prof://www.chem.leeds.ac.uk/People/Rayner.html Natural Products Chemistry / Sustainable Chemicals for the Future The large majority of chemically derived derived equivalents. There is also a perception (not always valid) that in consumer products, naturally

  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. 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;...

  17. Chemical Methods for the Synthesis and Modification of Neoclerodane Diterpenes

    PubMed Central

    Lozama, Anthony; Prisinzano, Thomas E.

    2009-01-01

    Diterpenes are a structural class of molecules that are derived from four isoprene subunits and are widespread throughout nature. A number of neoclerodane diterpenes have been found to have biological activity but a limited number of chemical investigations have been conducted. Recently, the neoclerodane diterpene, salvinorin A (12) has been investigated due to its unique pharmacological profile. This review will discuss the chemical methods used to chemically modify and synthesize 12. PMID:19679471

  18. Spectral Characterization of Plant-Derived Dissolved Organic Matter

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Dissolved organic matter (DOM) derived from fresh or early-stage decomposing soil amendment materials may play an important role in the process of organic matter accumulation. The DOM can influence many chemical processes, due to its reactivity with both soil solution components and soil surfaces. W...

  19. Acquiring Knowledge of Derived Nominals and Derived Adjectives in Context

    ERIC Educational Resources Information Center

    Marinellie, Sally A.; Kneile, Lynn A.

    2012-01-01

    Purpose: This research investigated children's ability to acquire semantic and syntactic knowledge of derived nominals and derived adjectives in the context of short passages. The study also investigated the relation of morphological awareness and the ability to acquire knowledge of derived words in context. Method: A total of 106 children in…

  20. Chemical Leukoderma Associated with Vicks VapoRub®

    PubMed Central

    Zirwas, Matthew J.

    2008-01-01

    Chemical leukoderma is seen in a variety of clinical settings. We present a case of leukoderma associated with the phenolic derivative thymol found in a common over-the-counter medication for nasal congestion. The proposed mechanism for this type of leukoderma is presented along with other sources of phenolic and catecholic derivatives. Treatment is also briefly reviewed. PMID:21212846

  1. 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.

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

    PubMed

    Dhamankar, Himanshu; Prather, Kristala L J

    2011-08-01

    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 evolved enzymes and pathways that can convert biomass into hundreds of unique chemical structures, a property that can be effectively exploited for their engineering into Microbial Chemical Factories (MCFs). De novo pathway engineering facilitates expansion of the repertoire of microbially synthesized compounds beyond natural products. In this review, we visit some recent successes in such novel pathway engineering and optimization, with particular emphasis on the selection and engineering of pathway enzymes and balancing of their accessory cofactors. PMID:21601443

  3. Emergency management of chemical weapons injuries.

    PubMed

    Anderson, Peter D

    2012-02-01

    The potential for chemical weapons to be used in terrorism is a real possibility. Classes of chemical weapons include nerve agents, vesicants (blister agents), choking agents, incapacitating agents, riot control agents, blood agents, and toxic industrial chemicals. The nerve agents work by blocking the actions of acetylcholinesterase leading to a cholinergic syndrome. Nerve agents include sarin, tabun, VX, cyclosarin, and soman. The vesicants include sulfur mustard and lewisite. The vesicants produce blisters and also damage the upper airways. Choking agents include phosgene and chlorine gas. Choking agents cause pulmonary edema. Incapacitating agents include fentanyl and its derivatives and adamsite. Riot control agents include Mace and pepper spray. Blood agents include cyanide. The mechanism of toxicity for cyanide is blocking oxidative phosphorylation. Toxic industrial chemicals include agents such as formaldehyde, hydrofluoric acid, and ammonia. PMID:22080590

  4. Ferroquine and its derivatives: new generation of antimalarial agents.

    PubMed

    Wani, Waseem A; Jameel, Ehtesham; Baig, Umair; Mumtazuddin, Syed; Hun, Lee Ting

    2015-08-28

    Malaria has been teasing human populations from a long time. Presently, several classes of antimalarial drugs are available in market, but the issues of toxicity, lower efficacy and the resistance by malarial parasites have decreased their overall therapeutic indices. Thus, the search for new promising antimalarials continues, however, the battle against malaria is far from over. Ferroquine is a derivative of chloroquine with antimalarial properties. It is the most successful of the chloroquine derivatives. Not only ferroquine, but also its derivatives have shown promising potential as antimalarials of clinical interest. Presently, much research is dedicated to the development of ferroquine derivatives as safe alternatives to antimalarial chemotherapy. The present article describes the structural, chemical and biological features of ferroquine. Several classes of ferroquine derivatives including hydroxyferroquines, trioxaferroquines, chloroquine-bridged ferrocenophanes, thiosemicarbazone derivatives, ferrocene dual conjugates, 4-N-substituted derivatives, and others have been discussed. Besides, the mechanism of action of ferroquine has been discussed. A careful observation has been made into pharmacologically significant ferroquine derivatives with better or equal therapeutic effects to that of chloroquine and ferroquine. A brief discussion of the toxicities of ferroquine derivatives has been made. Finally, efforts have been made to discuss the current challenges and future perspectives of ferroquine-based antimalarial drug development. PMID:26188909

  5. Experts' understanding of partial derivatives using the partial derivative machine

    NASA Astrophysics Data System (ADS)

    Roundy, David; Weber, Eric; Dray, Tevian; Bajracharya, Rabindra R.; Dorko, Allison; Smith, Emily M.; Manogue, Corinne A.

    2015-12-01

    [This paper is part of the Focused Collection on Upper Division Physics Courses.] Partial derivatives are used in a variety of different ways within physics. Thermodynamics, in particular, uses partial derivatives in ways that students often find especially confusing. We are at the beginning of a study of the teaching of partial derivatives, with a goal of better aligning the teaching of multivariable calculus with the needs of students in STEM disciplines. In this paper, we report on an initial study of expert understanding of partial derivatives across three disciplines: physics, engineering, and mathematics. We report on the central research question of how disciplinary experts understand partial derivatives, and how their concept images of partial derivatives differ, with a focus on experimentally measured quantities. Using the partial derivative machine (PDM), we probed expert understanding of partial derivatives in an experimental context without a known functional form. In particular, we investigated which representations were cued by the experts' interactions with the PDM. Whereas the physicists and engineers were quick to use measurements to find a numeric approximation for a derivative, the mathematicians repeatedly returned to speculation as to the functional form; although they were comfortable drawing qualitative conclusions about the system from measurements, they were reluctant to approximate the derivative through measurement. On a theoretical front, we found ways in which existing frameworks for the concept of derivative could be expanded to include numerical approximation.

  6. 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

  7. Chemical Transformation Simulator

    EPA Science Inventory

    The Chemical Transformation Simulator (CTS) is a web-based, high-throughput screening tool that automates the calculation and collection of physicochemical properties for an organic chemical of interest and its predicted products resulting from transformations in environmental sy...

  8. Chemical Industry Bandwidth Study

    SciTech Connect

    none,

    2006-12-01

    The Chemical Bandwidth Study provides a snapshot of potentially recoverable energy losses during chemical manufacturing. The advantage of this study is the use of "exergy" analysis as a tool for pinpointing inefficiencies.

  9. 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.

  10. Personal Chemical Exposure informatics

    EPA Science Inventory

    Chemical Exposure science is the study of human contact with chemicals (from manufacturing facilities, everyday products, waste) occurring in their environments and advances knowledge of the mechanisms and dynamics of events that cause or prevent adverse health outcomes. (adapted...

  11. Chemical burn or reaction

    MedlinePLUS

    ... different products that contain toxic chemicals such as ammonia and bleach. The mixture can give off hazardous ... chemicals immediately after use. Use paints, petroleum products, ammonia, bleach, and other products that give off fumes ...

  12. Chemicals Industry Vision

    SciTech Connect

    none,

    1996-12-01

    Chemical industry leaders articulated a long-term vision for the industry, its markets, and its technology in the groundbreaking 1996 document Technology Vision 2020 - The U.S. Chemical Industry. (PDF 310 KB).

  13. Accurate Calculation, Prediction, and Assignment of 3 Chemical Shifts of Helium-3-Encapsulated Fullerenes and

    E-print Network

    Wang, Guan-Wu

    -Encapsulated Fullerenes and Fullerene Derivatives Guan-Wu Wang,*, Xin-Hao Zhang, Huan Zhan, Qing-Xiang Guo-3 NMR chemical shifts of various 3 He-encapsulated fullerenes (3 He@Cn) and their derivatives have of the experimental and calculated 3 He NMR chemical shifts over a wide range of 3 He-encapsulated fullerene compounds

  14. 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.

  15. Establishing Chemical Technology Programs.

    ERIC Educational Resources Information Center

    Hajian, Harry G.

    In light of the increasing demand for well-prepared chemical technicians, this paper provides suggestions for two-year colleges interested in initiating or upgrading a chemical technology program. Introductory comments indicate that, from the industry standpoint, chemical technicians are invaluable, but inadequate in numbers and often unprepared.…

  16. 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.

  17. 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

  18. Chemical Zeolites Combinatorial . . .

    E-print Network

    Servatius, Brigitte

    . Chemical Zeolites · crystalline solid · units: Si + 4O Si O O O O · two covalent bonds per oxygen #12Chemical Zeolites Combinatorial . . . Realization 2d Zeolites Finite Zeolites The Layer . . . Holes University (Brigitte Servatius -- WPI) #12;Chemical Zeolites Combinatorial . . . Realization 2d Zeolites

  19. Hazard Communication & Chemical Safety

    E-print Network

    Haimovich, Alexander

    types of chemical hazards Physical Hazards Health Hazards The first rule of Chemical safety is by an approved procedure #12;Health Hazards Chemicals are classified as being a health hazard if they: Can cause cancer Are poisonous (toxic) Cause harm to your skin, internal organs, or nervous system Are corrosive

  20. 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.

  1. 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...

  2. Toxicology and Chemical Safety.

    ERIC Educational Resources Information Center

    Hall, Stephen K.

    1983-01-01

    Topics addressed in this discussion of toxicology and chemical safety include routes of exposure, dose/response relationships, action of toxic substances, and effects of exposure to chemicals. Specific examples are used to illustrate the principles discussed. Suggests prudence in handling any chemicals, whether or not toxicity is known. (JN)

  3. Chemical and Environmental Technology.

    ERIC Educational Resources Information Center

    Sheather, Harry

    The two-year curriculum in chemical technology presented in the document is designed to prepare high school graduates for technical positions in the chemical industry. Course outlines are given for general chemistry, chemical calculations, quantitative analysis, environmental chemistry, organic chemistry 1 and 2, instrumental analysis, and…

  4. Radioactively labelled porphyrin derivatives

    NASA Astrophysics Data System (ADS)

    Koní?ová, R.; Ernestová, M.; Jedináková-K?ížová, V.; Král, V.

    2003-01-01

    Radioactive labelling of guanidine-bearing tetraphenylporphyrin and Dy—texaphyrin with selected radionuclides (166Ho and 90Y) is described. A basic characterisation of studied porphyrin and texaphyrin, including their behaviour in a wide range of pH values and data on holmium and yttrium complexation with these compounds was probed using UV-VIS absorption spectrometry. The labelling yield of these macrocyclic molecules depends on the pH of the reaction mixture, metal: ligand ratio and time of incubation. Optimal reaction conditions for formation of porphyrin and texaphyrin radioactive complexes were determined by thin layer chromatography with the detection of ?- activity. The ability of porphyrin derivatives to bind anions was examined as well. Our experiments were focused on perrhenate ion (ReO4 -) because radiopharmaceuticals labelled with isotopes 186Re and 188Re play an important role in therapy of numerous tumour diseases. The possibility of applying ReO4 - anion directly for labelling purposes, without the necessity of its reduction to lower oxidation state, was not proved.

  5. High Throughput Exposure Prioritization of Chemicals Using a Screening-Level Probabilistic SHEDS-Lite Exposure Model

    EPA Science Inventory

    These novel modeling approaches for screening, evaluating and classifying chemicals based on the potential for biologically-relevant human exposures will inform toxicity testing and prioritization for chemical risk assessment. The new modeling approach is derived from the Stocha...

  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 earth models

    NASA Astrophysics Data System (ADS)

    Javoy, Marc

    1999-10-01

    This article presents a critical review of method, concepts and prejudices used bv modelists of the Earth's chemical composition over approximate the last fifty years and of the resulting compositions. Brief descriptions are given of admitted accretion mechanisms, of the starting materials most often considered and of the major parameters and recurrent concepts: 'reduced" state, mantle homogeneity vs heterogeneity, 'low pressure' core formation, 'great impact', refractory, lithophile, siderophile, compatible, incompatible character of elements, depleted and degassed mantle, Urey ratio, as well as the description of a commonly-used instrument, possibly harmful to Iogic, the famous Ockham's razor. Differences between models are now restricted to the lower mantle composition:the 'primary' (before crust differentiation) upper mentle varies little from model to model and the idea of a 10-15% combined Si-O-S concentration as representing the necessary light elements in the core is gaining more and more ground. The dominant type of model derives more or less directly from the CI cabonaceous composition by complete devolatilization and reduction. Its mantle is homogeneous and convecting mainly in a one-level mode, in accordence with dominant geophysicists' views but in rather strong disagreement with geochemical data and models which insist on the strong decoupling between lower and upper mantle. Its low Si excess is generally supposed to have been absorbed by the core, whereas its high refractory lithophile element (RLE) content creates mass balance problems relative to presently observed mantle and crust concentrations. The alternative type is a two-lavel mantle with a Si and Fe-rich, RLE-poor, lower mantle, previously based mainly on seismic and mineral physics data, and now also on geochemical and cosmochemical arguments.

  8. 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.

  9. Four novel spirooxazacamphorsultam derivatives.

    PubMed

    Wilke, Burkhardt I; Goodenough, Angela K; Bausch, Cory C; Cline, Erika N; Abrams, M Leigh; Fayer, Effrat L; Swenson, Dale C; Cermak, Diana M

    2010-12-01

    The chiral compounds (6aS,9S,10aR)-11,11-dimethyl-5,5-dioxo-2,3,8,9-tetrahydro-6H-6a,9-methanooxazaolo[2,3-i][2,1]benzisothiazol-10(7H)-one, C(12)H(17)NO(4)S, (1), (7aS,10S,11aR)-12,12-dimethyl-6,6-dioxo-3,4,9,10-tetrahydro-7H-7a,10-methano-2H-1,3-oxazino[2,3-i][2,1]benzisothiazol-11(8H)-one, C(13)H(19)NO(4)S, (2), (6aS,9S,10R,10aR)-11,11-dimethyl-5,5-dioxo-2,3,7,8,9,10-hexahydro-6H-6a,9-methanooxazolo[2,3-i][2,1]benzisothiazol-10-ol, C(12)H(19)NO(4)S, (3), and (7aS,10S,11R,11aR)-12,12-dimethyl-6,6-dioxo-3,4,8,9,10,11-hexahydro-7H-7a-methano-2H-[1,3]oxazino[2,3-i][2,1]benzisothiazol-11-ol, C(13)H(21)NO(4)S, (4), consist of a camphor core with a five-membered spirosultaoxazolidine or six-membered spirosultaoxazine, as both their keto and hydroxy derivatives. In each structure, the molecules are linked via hydrogen bonding to the sulfonyl O atoms, forming chains in the unit-cell b-axis direction. The chains interconnect via weak C-H...O interactions. The keto compounds have very similar packing but represent the highest melting [507-508?K for (1)] and lowest melting [457-458?K for (2)] solids. PMID:21123893

  10. UCI Chemical Hygiene Plan i August 2014 CHEMICAL HYGIENE PLAN

    E-print Network

    Nizkorodov, Sergey

    UCI Chemical Hygiene Plan i August 2014 CHEMICAL HYGIENE PLAN University of California, Irvine (949) 824-8539 #12;UCI Chemical Hygiene Plan ii August 2014 Chemical Hygiene Plan (CHP) Chapters..................................................... A-1 Appendix B: Container Labelling

  11. Wyss Institute Chemical Hygiene Plan CHEMICAL HYGIENE PLAN

    E-print Network

    Napp, Nils

    Wyss Institute Chemical Hygiene Plan CHEMICAL HYGIENE PLAN The Wyss Institute for Biologically Inspired Engineering June 2015 #12;Wyss Institute Chemical Hygiene Plan TABLE OF CONTENTS 1.0 POLICY..........................................................................................2 2.1 CHEMICAL HYGIENE OFFICER

  12. Wyss Institute Chemical Hygiene Plan CHEMICAL HYGIENE PLAN

    E-print Network

    Church, George M.

    Wyss 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.......................................................................................... 2 2.1 CHEMICAL HYGIENE OFFICER

  13. 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.

  14. 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.

  15. 40 CFR 721.1230 - Benzene, ethenyl-, ar-bromo derivatives.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... removed from a container that has held the substance, unless the container is empty as defined in 40 CFR... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Benzene, ethenyl-, ar-bromo... Specific Chemical Substances § 721.1230 Benzene, ethenyl-, ar-bromo derivatives. (a) Chemical substance...

  16. 40 CFR 721.1230 - Benzene, ethenyl-, ar-bromo derivatives.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... removed from a container that has held the substance, unless the container is empty as defined in 40 CFR... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Benzene, ethenyl-, ar-bromo... Specific Chemical Substances § 721.1230 Benzene, ethenyl-, ar-bromo derivatives. (a) Chemical substance...

  17. 40 CFR 721.1230 - Benzene, ethenyl-, ar-bromo derivatives.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... removed from a container that has held the substance, unless the container is empty as defined in 40 CFR... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Benzene, ethenyl-, ar-bromo... Specific Chemical Substances § 721.1230 Benzene, ethenyl-, ar-bromo derivatives. (a) Chemical substance...

  18. 40 CFR 721.1230 - Benzene, ethenyl-, ar-bromo derivatives.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... removed from a container that has held the substance, unless the container is empty as defined in 40 CFR... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Benzene, ethenyl-, ar-bromo... Specific Chemical Substances § 721.1230 Benzene, ethenyl-, ar-bromo derivatives. (a) Chemical substance...

  19. 40 CFR 721.1230 - Benzene, ethenyl-, ar-bromo derivatives.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... removed from a container that has held the substance, unless the container is empty as defined in 40 CFR... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Benzene, ethenyl-, ar-bromo... Specific Chemical Substances § 721.1230 Benzene, ethenyl-, ar-bromo derivatives. (a) Chemical substance...

  20. 40 CFR 721.10148 - Acryloxy alkanoic alkane derivative with mixed metal oxides (generic).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... with mixed metal oxides (generic). 721.10148 Section 721.10148 Protection of Environment ENVIRONMENTAL... mixed metal oxides (generic). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as acryloxy alkanoic alkane derivative with mixed...

  1. 40 CFR 721.10148 - Acryloxy alkanoic alkane derivative with mixed metal oxides (generic).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... with mixed metal oxides (generic). 721.10148 Section 721.10148 Protection of Environment ENVIRONMENTAL... mixed metal oxides (generic). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as acryloxy alkanoic alkane derivative with mixed...

  2. New derivatives of nonactic and homononactic acids from Bacillus pumilus derived from Breynia fruticosa.

    PubMed

    Han, Li; Huo, Peiyuan; Chen, Huahong; Li, Songtao; Jiang, Yi; Li, Liya; Xu, Lihua; Jiang, Chenglin; Huang, Xueshi

    2014-07-01

    Six new nonactic and homononactic acid derivatives, ethyl homononactate (1), ethyl nonactate (2), homononactyl homononactate (6), ethyl homononactyl nonactate (7), ethyl homononactyl homononactate (8), and ethyl nonactyl nonactate (9), as well as four known compounds, homononactic acid (3), nonactic acid (4), homononactyl nonactate (5), and bishomononactic acid (10), were isolated from culture broth of Bacillus pumilus derived from Breynia fruticosa. The structures of new compounds were elucidated by spectroscopic analysis and chemical methods. The optical purities of 1-6 were determined by HPLC/MS after treatment with L-phenylalanine methyl ester. The dimeric compounds 5-9 showed weak cytotoxic activities against five human cancer cell lines (IC50 19-100??g/ml). PMID:25044594

  3. 40 CFR 721.10056 - Benzenemethanaminium, N-(3-aminopropyl)-N,N-dimethyl-, N-soya acyl derivs., chlorides.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...)-N,N-dimethyl-, N-soya acyl derivs., chlorides. 721.10056 Section 721.10056 Protection of Environment...-aminopropyl)-N,N-dimethyl-, N-soya acyl derivs., chlorides. (a) Chemical substance and significant new uses...-dimethyl-, N-soya acyl derivs., chlorides (PMN P-03-47; CAS No. 90194-13-1) is subject to reporting...

  4. 40 CFR 721.10056 - Benzenemethanaminium, N-(3-aminopropyl)-N,N-dimethyl-, N-soya acyl derivs., chlorides.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...)-N,N-dimethyl-, N-soya acyl derivs., chlorides. 721.10056 Section 721.10056 Protection of Environment...-aminopropyl)-N,N-dimethyl-, N-soya acyl derivs., chlorides. (a) Chemical substance and significant new uses...-dimethyl-, N-soya acyl derivs., chlorides (PMN P-03-47; CAS No. 90194-13-1) is subject to reporting...

  5. 40 CFR 721.7270 - 1-propanaminium, 3-amino-, N,N,N-trimethyl-N-soya acyl derivs., chloride.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...N-trimethyl-N-soya acyl derivs., chloride. 721.7270 Section 721.7270...trimethyl-N-soya acyl derivs., chloride. (a) Chemical substance and significant...trimethyl-N-soya acyl derivs., chloride (PMN P-01-646; CAS No....

  6. 40 CFR 721.10056 - Benzenemethanaminium, N-(3-aminopropyl)-N,N-dimethyl-, N-soya acyl derivs., chlorides.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...N-dimethyl-, N-soya acyl derivs., chlorides. 721.10056 Section 721.10056...dimethyl-, N -soya acyl derivs., chlorides. (a) Chemical substance and significant...dimethyl-, N -soya acyl derivs., chlorides (PMN P-03-47; CAS No....

  7. 40 CFR 721.10056 - Benzenemethanaminium, N-(3-aminopropyl)-N,N-dimethyl-, N-soya acyl derivs., chlorides.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...N-dimethyl-, N-soya acyl derivs., chlorides. 721.10056 Section 721.10056...dimethyl-, N -soya acyl derivs., chlorides. (a) Chemical substance and significant...dimethyl-, N -soya acyl derivs., chlorides (PMN P-03-47; CAS No....

  8. 40 CFR 721.10056 - Benzenemethanaminium, N-(3-aminopropyl)-N,N-dimethyl-, N-soya acyl derivs., chlorides.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...N-dimethyl-, N-soya acyl derivs., chlorides. 721.10056 Section 721.10056...dimethyl-, N -soya acyl derivs., chlorides. (a) Chemical substance and significant...dimethyl-, N -soya acyl derivs., chlorides (PMN P-03-47; CAS No....

  9. 40 CFR 721.7270 - 1-propanaminium, 3-amino-, N,N,N-trimethyl-N-soya acyl derivs., chloride.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...N-trimethyl-N-soya acyl derivs., chloride. 721.7270 Section 721.7270...trimethyl-N-soya acyl derivs., chloride. (a) Chemical substance and significant...trimethyl-N-soya acyl derivs., chloride (PMN P-01-646; CAS No....

  10. 40 CFR 721.7270 - 1-propanaminium, 3-amino-, N,N,N-trimethyl-N-soya acyl derivs., chloride.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...N-trimethyl-N-soya acyl derivs., chloride. 721.7270 Section 721.7270...trimethyl-N-soya acyl derivs., chloride. (a) Chemical substance and significant...trimethyl-N-soya acyl derivs., chloride (PMN P-01-646; CAS No....

  11. 40 CFR 721.7270 - 1-propanaminium, 3-amino-, N,N,N-trimethyl-N-soya acyl derivs., chloride.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...N-trimethyl-N-soya acyl derivs., chloride. 721.7270 Section 721.7270...trimethyl-N-soya acyl derivs., chloride. (a) Chemical substance and significant...trimethyl-N-soya acyl derivs., chloride (PMN P-01-646; CAS No....

  12. 40 CFR 721.7270 - 1-propanaminium, 3-amino-, N,N,N-trimethyl-N-soya acyl derivs., chloride.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...N-trimethyl-N-soya acyl derivs., chloride. 721.7270 Section 721.7270...trimethyl-N-soya acyl derivs., chloride. (a) Chemical substance and significant...trimethyl-N-soya acyl derivs., chloride (PMN P-01-646; CAS No....

  13. 40 CFR 721.10056 - Benzenemethanaminium, N-(3-aminopropyl)-N,N-dimethyl-, N-soya acyl derivs., chlorides.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...N-dimethyl-, N-soya acyl derivs., chlorides. 721.10056 Section 721.10056...dimethyl-, N -soya acyl derivs., chlorides. (a) Chemical substance and significant...dimethyl-, N -soya acyl derivs., chlorides (PMN P-03-47; CAS No....

  14. 40 CFR 721.10056 - Benzenemethanaminium, N-(3-aminopropyl)-N,N-dimethyl-, N-soya acyl derivs., chlorides.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...N-dimethyl-, N-soya acyl derivs., chlorides. 721.10056 Section 721.10056...dimethyl-, N -soya acyl derivs., chlorides. (a) Chemical substance and significant...dimethyl-, N -soya acyl derivs., chlorides (PMN P-03-47; CAS No....

  15. 40 CFR 721.10056 - Benzenemethanaminium, N-(3-aminopropyl)-N,N-dimethyl-, N-soya acyl derivs., chlorides.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...)-N,N-dimethyl-, N-soya acyl derivs., chlorides. 721.10056 Section 721.10056 Protection of Environment...-aminopropyl)-N,N-dimethyl-, N-soya acyl derivs., chlorides. (a) Chemical substance and significant new uses...-dimethyl-, N-soya acyl derivs., chlorides (PMN P-03-47; CAS No. 90194-13-1) is subject to reporting...

  16. 40 CFR 721.10056 - Benzenemethanaminium, N-(3-aminopropyl)-N,N-dimethyl-, N-soya acyl derivs., chlorides.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...)-N,N-dimethyl-, N-soya acyl derivs., chlorides. 721.10056 Section 721.10056 Protection of Environment...-aminopropyl)-N,N-dimethyl-, N-soya acyl derivs., chlorides. (a) Chemical substance and significant new uses...-dimethyl-, N-soya acyl derivs., chlorides (PMN P-03-47; CAS No. 90194-13-1) is subject to reporting...

  17. 40 CFR 721.9078 - 6-Methoxy-1H-benz[de]isoquinoline-2 [3H]-dione derivative (generic).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...de]isoquinoline-2 [3H]-dione derivative (generic). 721.9078 Section...de]isoquinoline-2 [3H]-dione derivative (generic). (a) Chemical substance...de]isoquinoline-2 [3H]-dione derivative (PMN P-00-1205) is subject...

  18. 40 CFR 721.9078 - 6-Methoxy-1H-benz[de]isoquinoline-2 [3H]-dione derivative (generic).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...de]isoquinoline-2 [3H]-dione derivative (generic). 721.9078 Section...de]isoquinoline-2 [3H]-dione derivative (generic). (a) Chemical substance...de]isoquinoline-2 [3H]-dione derivative (PMN P-00-1205) is subject...

  19. Digital and analog chemical evolution.

    PubMed

    Goodwin, Jay T; Mehta, Anil K; Lynn, David G

    2012-12-18

    Living matter is the most elaborate, elegant, and complex hierarchical material known and is consequently the natural target for an ever-expanding scientific and technological effort to unlock and deconvolute its marvelous forms and functions. Our current understanding suggests that biological materials are derived from a bottom-up process, a spontaneous emergence of molecular networks in the course of chemical evolution. Polymer cooperation, so beautifully manifested in the ribosome, appeared in these dynamic networks, and the special physicochemical properties of the nucleic and amino acid polymers made possible the critical threshold for the emergence of extant cellular life. These properties include the precise and geometrically discrete hydrogen bonding patterns that dominate the complementary interactions of nucleic acid base-pairing that guide replication and ensure replication fidelity. In contrast, complex and highly context-dependent sets of intra- and intermolecular interactions guide protein folding. These diverse interactions allow the more analog environmental chemical potential fluctuations to dictate conformational template-directed propagation. When these two different strategies converged in the remarkable synergistic ribonucleoprotein that is the ribosome, this resulting molecular digital-to-analog converter achieved the capacity for both persistent information storage and adaptive responses to an ever-changing environment. The ancestral chemical networks that preceded the Central Dogma of Earth's biology must reflect the dynamic chemical evolutionary landscapes that allowed for selection, propagation, and diversification and ultimately the demarcation and specialization of function that modern biopolymers manifest. Not only should modern biopolymers contain molecular fossils of this earlier age, but it should be possible to use this information to reinvent these dynamic functional networks. In this Account, we review the first dynamic network created by modification of a nucleic acid backbone and show how it has exploited the digital-like base pairing for reversible polymer construction and information transfer. We further review how these lessons have been extended to the complex folding landscapes of templated peptide assembly. These insights have allowed for the construction of molecular hybrids of each biopolymer class and made possible the reimagining of chemical evolution. Such elaboration of biopolymer chimeras has already led to applications in therapeutics and diagnostics, to the construction of novel nanostructured materials, and toward orthogonal biochemical pathways that expand the evolution of existing biochemical systems. The ability to look beyond the primordial emergence of the ribosome may allow us to better define the origins of chemical evolution, to extend its horizons beyond the biology of today and ask whether evolution is an inherent property of matter unbounded by physical limitations imposed by our planet's diverse environments. PMID:23098254

  20. Chemical space networks: a powerful new paradigm for the description of chemical space.

    PubMed

    Maggiora, Gerald M; Bajorath, Jürgen

    2014-08-01

    The concept of chemical space is playing an increasingly important role in many areas of chemical research, especially medicinal chemistry and chemical biology. It is generally conceived as consisting of numerous compound clusters of varying sizes scattered throughout the space in much the same way as galaxies of stars inhabit our universe. A number of issues associated with this coordinate-based representation are discussed. Not the least of which is the continuous nature of the space, a feature not entirely compatible with the inherently discrete nature of chemical space. Cell-based representations, which are derived from coordinate-based spaces, have also been developed that facilitate a number of chemical informatic activities (e.g., diverse subset selection, filling 'diversity voids', and comparing compound collections).These representations generally suffer the 'curse of dimensionality'. In this work, networks are proposed as an attractive paradigm for representing chemical space since they circumvent many of the issues associated with coordinate- and cell-based representations, including the curse of dimensionality. In addition, their relational structure is entirely compatible with the intrinsic nature of chemical space. A description of the features of these chemical space networks is presented that emphasizes their statistical characteristics and indicates how they are related to various types of network topologies that exhibit random, scale-free, and/or 'small world' properties. PMID:24925682

  1. Chitooligosaccharide and its derivatives: preparation and biological applications.

    PubMed

    Lodhi, Gaurav; Kim, Yon-Suk; 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

  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. Chemical evolution STRUCTURE OF GALAXIES

    E-print Network

    Kruit, Piet van der

    Outline Absorption Chemical evolution STRUCTURE OF GALAXIES 8. Absorption; chemical evolution Piet Piet van der Kruit, Kapteyn Astronomical Institute Absorption; chemical evolution #12;Outline Absorption Chemical evolution Outline Absorption Holmberg's analysis Analysis of Disney et al. Edge

  4. Quantum mechanics of higher derivative systems and total derivative terms

    NASA Astrophysics Data System (ADS)

    Kaminaga, Yasuhito

    1996-08-01

    A general theory is presented of the classical and quantum mechanics of singular, non-autonomous, higher derivative systems. It is shown that adding a total derivative to a Lagrangian does not materially affect either, (a) the canonical analysis of the system, or (b) its quantum mechanics.

  5. Rotenoid derivatives from Derris trifoliata with nitric oxide production inhibitory activity.

    PubMed

    Ito, Chihiro; Murata, Tomiyasu; Tan, Hugh T-W; Kaneda, Norio; Furukawa, Hiroshi; Itoigawa, Masataka

    2012-11-01

    Study of the chemical constituents of the stems of Derris trifoliata Lour. (Leguminosae) collected in Singapore led to the isolation and identification of three known and two new rotenoid derivatives. The new derivatives, named derrisfolin A (1) and B (2), inhibited nitric oxide production in murine macrophage-like RAW 264.7 cells stimulated with interferon-gamma and lipopolysaccharide. PMID:23285811

  6. Automated compound classification using a chemical ontology

    PubMed Central

    2012-01-01

    Background Classification of chemical compounds into compound classes by using structure derived descriptors is a well-established method to aid the evaluation and abstraction of compound properties in chemical compound databases. MeSH and recently ChEBI are examples of chemical ontologies that provide a hierarchical classification of compounds into general compound classes of biological interest based on their structural as well as property or use features. In these ontologies, compounds have been assigned manually to their respective classes. However, with the ever increasing possibilities to extract new compounds from text documents using name-to-structure tools and considering the large number of compounds deposited in databases, automated and comprehensive chemical classification methods are needed to avoid the error prone and time consuming manual classification of compounds. Results In the present work we implement principles and methods to construct a chemical ontology of classes that shall support the automated, high-quality compound classification in chemical databases or text documents. While SMARTS expressions have already been used to define chemical structure class concepts, in the present work we have extended the expressive power of such class definitions by expanding their structure-based reasoning logic. Thus, to achieve the required precision and granularity of chemical class definitions, sets of SMARTS class definitions are connected by OR and NOT logical operators. In addition, AND logic has been implemented to allow the concomitant use of flexible atom lists and stereochemistry definitions. The resulting chemical ontology is a multi-hierarchical taxonomy of concept nodes connected by directed, transitive relationships. Conclusions A proposal for a rule based definition of chemical classes has been made that allows to define chemical compound classes more precisely than before. The proposed structure-based reasoning logic allows to translate chemistry expert knowledge into a computer interpretable form, preventing erroneous compound assignments and allowing automatic compound classification. The automated assignment of compounds in databases, compound structure files or text documents to their related ontology classes is possible through the integration with a chemical structure search engine. As an application example, the annotation of chemical structure files with a prototypic ontology is demonstrated. PMID:23273256

  7. 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.

  8. ALTERNATIVE FUELS AND CHEMICALS FROM SYNTHESIS GAS

    SciTech Connect

    Peter Tijrn

    2003-02-03

    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. Alternative Fuels and Chemicals from Synthesis Gas

    SciTech Connect

    Peter Tijrn

    2003-01-02

    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.

  10. ALTERNATIVE FUELS AND CHEMICALS FROM SYNTHESIS GAS

    SciTech Connect

    Peter J. Tijrn

    2000-06-30

    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.

  11. ALTERNATIVE FUELS AND CHEMICALS FROM SYNTHESIS GAS

    SciTech Connect

    Unknown

    2001-09-30

    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.

  12. ALTERNATIVE FUELS AND CHEMICALS FROM SYNTHESIS GAS

    SciTech Connect

    Unknown

    1999-04-01

    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.

  13. ALTERNATIVE FUELS AND CHEMICALS FROM SYNTHESIS GAS

    SciTech Connect

    Unknown

    1999-01-01

    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.

  14. ALTERNATIVE FUELS AND CHEMICALS FROM SYNTHESIS GAS

    SciTech Connect

    Peter J. Tijrn

    2000-09-30

    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.

  15. ALTERNATIVE FUELS AND CHEMICALS FROM SYNTHESIS GAS

    SciTech Connect

    Unknown

    2002-03-31

    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.

  16. Holographic recording materials development. [using stilbene, indigo, and thioindigo derivatives

    NASA Technical Reports Server (NTRS)

    1975-01-01

    The area of organic cis-trans photoisomerization systems for holographic memory applications was examined. Photochemical studies were made of stilbene, indigo, and thioindigo derivatives in solution and in a variety of polymer matrix materials, to optimize the photorefractive behavior of the chemical system as a whole. Lithium niobate was used to study the writing and reading efficiencies of thick phase holograms. Both phase-wave holograms and Fourier-transform holograms were employed, and a number of reconstruction techniques are discussed. The possibility of using cis-trans photoisomerization of appropriate organic chemicals as the basis for a holographic recording system is confirmed.

  17. 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.

  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. Metformin for cancer and aging prevention: is it a time to make the long story short?

    PubMed

    Anisimov, Vladimir N

    2015-11-24

    During the last decade, the burst of interest is observed to antidiabetic biguanide metformin as candidate drug for cancer chemoprevention. The analysis of the available data have shown that the efficacy of cancer preventive effect of metformin (MF) and another biguanides, buformin (BF) and phenformin (PF), has been studied in relation to total tumor incidence and to 17 target organs, in 21 various strains of mice, 4 strains of rats and 1 strain of hamsters (inbred, outbred, transgenic, mutant), spontaneous (non- exposed to any carcinogenic agent) or induced by 16 chemical carcinogens of different classes (polycycIic aromatic hydrocarbons, nitroso compounds, estrogen, etc.), direct or indirect (need metabolic transformation into proximal carcinogen), by total body X-rays and ?- irradiation, viruses, genetic modifications or special high fat diet, using one stage and two-stage protocols of carcinogenesis, 5 routes of the administration of antidiabetic biguanides (oral gavage, intraperitoneal or subcutaneous injections, with drinking water or with diet) in a wide ranks of doses and treatment regimens. In the majority of cases (86%) the treatment with biguanides leads to inhibition of carcinogenesis. In 14% of the cases inhibitory effect of the drugs was not observed. Very important that there was no any case of stimulation of carcinogenesis by antidiabetic biguanides. It was conclude that there is sufficient experimental evidence of anti-carcinogenic effect of antidiabetic biguanides. PMID:26583576

  20. 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.