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1

Antidiabetic and antimalarial biguanide drugs are metal-interactive antiproteolytic agents  

Microsoft Academic Search

Various biguanide derivatives are used as antihyperglycemic and antimalarial drugs (e.g., 1,1-dimethyl biguanide (metformin), phenylethyl biguanide (phenformin), N-(4-chlorophenyl)-N?-(isopropyl)-imidodicarbonimidic diamide (proguanil)); however, no common mechanism has been suggested in these controversial therapeutic actions. Biguanides bind endogenous metals that inhibit cysteine proteases independently, e.g., Zn2+, Cu2+, Fe3+. Here, various biguanide derivatives are reported to be metal-interactive inhibitors of cathepsin B from mammals

Deacon Sweeney; Michael L. Raymer; Thomas D. Lockwood

2003-01-01

2

Environmental fate of polyhexamethylene biguanide.  

PubMed

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

Lucas, Anne D

2011-10-29

3

Phagocytosis affects biguanide sensitivity of Acanthamoeba spp.  

PubMed

The incidence of Acanthamoeba keratitis, a disease associated with contact lens wear, has been in apparent decline with the advent of multipurpose contact lens solutions. The concentrations of the biguanides chlorhexidine digluconate (CHX) and particularly polyhexamethylene biguanide (PHMB) included in multipurpose solutions (MPSs) are sublethal for amoebae. We evaluated by flow cytometry the effects of these two biguanides on phagocytosis of particles and the survival of trophozoites of Acanthamoeba castellanii and A. polyphaga. Trophozoites of A. castellanii and A. polyphaga (10(6)/ml) were exposed to solutions of 5 and 50 microg of PHMB and CHX per ml in the presence and absence of particles (i.e., heat-killed yeasts and bacteria and latex beads). In addition, trophozoites were exposed to particles treated with these concentrations of the two biguanides. In the absence of particles, trophozoites of A. polyphaga appeared to be more resistant to the biguanides than those of A. castellanii. In the presence of particles, the rates of survival of both species were decreased. In most instances, particles treated with sublethal concentrations of both biguanides that were adsorbed onto the particles reduced the incidence of phagocytosis. Particles present in MPSs in contact lens cases may be involved in the decreased incidence of Acanthamoeba keratitis. PMID:12069957

Noble, Judith A; Ahearn, Donald G; Avery, Simon V; Crow, Sidney A

2002-07-01

4

Phagocytosis Affects Biguanide Sensitivity of Acanthamoeba spp.  

PubMed Central

The incidence of Acanthamoeba keratitis, a disease associated with contact lens wear, has been in apparent decline with the advent of multipurpose contact lens solutions. The concentrations of the biguanides chlorhexidine digluconate (CHX) and particularly polyhexamethylene biguanide (PHMB) included in multipurpose solutions (MPSs) are sublethal for amoebae. We evaluated by flow cytometry the effects of these two biguanides on phagocytosis of particles and the survival of trophozoites of Acanthamoeba castellanii and A. polyphaga. Trophozoites of A. castellanii and A. polyphaga (106/ml) were exposed to solutions of 5 and 50 ?g of PHMB and CHX per ml in the presence and absence of particles (i.e., heat-killed yeasts and bacteria and latex beads). In addition, trophozoites were exposed to particles treated with these concentrations of the two biguanides. In the absence of particles, trophozoites of A. polyphaga appeared to be more resistant to the biguanides than those of A. castellanii. In the presence of particles, the rates of survival of both species were decreased. In most instances, particles treated with sublethal concentrations of both biguanides that were adsorbed onto the particles reduced the incidence of phagocytosis. Particles present in MPSs in contact lens cases may be involved in the decreased incidence of Acanthamoeba keratitis.

Noble, Judith A.; Ahearn, Donald G.; Avery, Simon V.; Crow Jr., Sidney A.

2002-01-01

5

Potential applications for biguanides in oncology.  

PubMed

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

Pollak, Michael

2013-09-03

6

Insulin and longevity: antidiabetic biguanides as geroprotectors  

Microsoft Academic Search

The results of previous experimental studies of effects of antidiabetic biguanides (phenformin and buformin) on life span\\u000a and spontaneous tumor incidence in mice and rats were recalculated and reanalyzed using standard demographic models of mortality.\\u000a The chronic treatment of female C3H\\/Sn mice with phenformin prolonged the mean life span by 21.1% (P < 0.05), the mean life span of the

Vladimir N. Anisimov; Anna V. Semenchenko; Anatoli I. Yashin

2003-01-01

7

Occupationally derived chemicals in breast milk  

Microsoft Academic Search

Exogenously derived chemicals have been widely reported in breast milk. Chemicals typically found in occupational exposures, including trace metals, solvents, and halogenated hydrocarbons, are reviewed, in terms of milk partition factors, potential infant exposures, and possible infant health effects. In addition to ingestion of a chemical from breast milk, an infant incurs a neonatal body burden of a chemical due

Mary S. Wolff

1983-01-01

8

Inhibition of intestinal amino acid transport by blood sugar lowering biguanides  

Microsoft Academic Search

Summary  The effect of blood-glucose lowering biguanides (phenethyl- and butylbiguanide) on active intestinal transport of different amino acids has been tested in hamster small intestinein vitro. —.Biguanides inhibited active transport of all amino acids tested. The inhibitory effect of biguanides increased with incubation time, was more pronounced after preincubation of intestinal tissue and was found to be non-competitive. The minimal inhibitory

W. Creutzfeldt

1973-01-01

9

Chemically Derived, Ultrasmooth Graphene Nanoribbon Semiconductors  

Microsoft Academic Search

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

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

2008-01-01

10

Occupationally derived chemicals in breast milk  

SciTech Connect

Exogenously derived chemicals have been widely reported in breast milk. Chemicals typically found in occupational exposures, including trace metals, solvents, and halogenated hydrocarbons, are reviewed, in terms of milk partition factors, potential infant exposures, and possible infant health effects. In addition to ingestion of a chemical from breast milk, an infant incurs a neonatal body burden of a chemical due to transplacental migration from maternal blood. For trace metals, neonatal blood levels are similar to maternal blood levels. Partition of metals to milk is less efficient, but nevertheless can contribute significantly to an infant's body burden. For lipid-soluble pesticide residues and halogenated biphenyls, neonatal body burden is much less than that of the mother, but transfer to milk is efficient, due to the high proportion of milk fat. It is suggested that potential organic mercury toxicity can be estimated from concentration in maternal blood or milk. For other chemicals, available data are not sufficient to evaluate short- or long-term health effects. However, for many halogenated hydrocarbons, concentrations in normal human milk would permit infant exposure above guidelines for allowable daily intake set by the World Health organization.

Wolff, M.S.

1983-01-01

11

Polyhexamethylene biguanide functionalized cationic silver nanoparticles for enhanced antimicrobial activity  

PubMed Central

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

2012-01-01

12

Production of Chemical Derivatives from Renewables  

SciTech Connect

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.

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

1996-06-01

13

Quantum chemical studies of some pyridine derivatives as corrosion inhibitors  

Microsoft Academic Search

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

C Ö?retir; B Mihçi; G Bereket

1999-01-01

14

PhysicoChemical Characterization of Sesame Oil Derivatives  

Microsoft Academic Search

Ozone treatment of commercially available vegetable oils gives rise to the formation of chemical species that are responsible\\u000a for the therapeutic properties of ozonated oil derivatives in dermatological diseases. In the last years, these products have\\u000a been successfully used as a topical disinfectant in a number of serious skin affections. The medical application of empirically\\u000a prepared ozonated oil has yielded

Iacopo Zanardi; Valter Travagli; Alessandro Gabbrielli; Luisa Chiasserini; Velio Bocci

2008-01-01

15

Biological activity of oleanane triterpene derivatives obtained by chemical derivatization.  

PubMed

Nine new derivatives of oleanane triterpenoids isolated from Fatsia polycarpa Hayata were synthesized through chemical transformations. Acetylation was effected by reaction with acetic anhydride in pyridine to afford compounds 1-5, while compound 6 was obtained using 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDC·HCl) in CH2Cl2. The others derivatives 7-9 were obtained in reactions of the corresponding triterpenoids with EDC·HCl, 4-N,N-dimethylaminopyridine hydrochloride and 4-N,N-dimethylaminopyridine in CH2Cl2. The structures of 1-9 were elucidated from extensive spectroscopic and HRESIMS data, while the structure of 9 was further confirmed by X-ray diffraction analysis. The cytotoxic, anti-hepatitis B virus (HBV), antibacterial, hypoglycaemic and Wnt signaling activities of these derivatives were evaluated in vitro. PMID:24145793

Cheng, Shi-Yie; Wang, Chao-Min; Cheng, Hsueh-Ling; Chen, Hui-Jye; Hsu, Yuan-Man; Lin, Yu-Chi; Chou, Chang-Hung

2013-10-18

16

Regulation of the Proliferation of Colon Cancer Cells by Compounds that Affect Glycolysis, Including 3-Bromopyruvate, 2-Deoxyglucose and Biguanides  

PubMed Central

In previous studies we observed that 2-deoxyglucose blocked the acidification of the medium used for culture of colon cancer cells caused by incubation with biguanides and had an additive inhibitory effect on growth. In the present work, we found that 3-bromopyruvate can also prevent the lowering of pH caused by biguanide treatment. 3-Bromopyruvate inhibited colonic cancer cell proliferation but the effect was not always additive to that of biguanides and an additive effect was more notable in combined treatment with 3-bromopyruvate and 2-deoxyglucose. The induction of alkaline phosphatase activity by butyrate was not consistently affected by combination with other agents that modified glucose metabolism. The drug combinations that were examined inhibited proliferation of wild-type and P53 null cells and affected colonic cancer lines with different growth rates.

Lea, Michael A.; Qureshi, Mehreen S.; Buxhoeveden, Michael; Gengel, Nicolette; Kleinschmit, Jessica; desBordes, Charles

2013-01-01

17

Marine derived polysaccharides for biomedical applications: chemical modification approaches.  

PubMed

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

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

2008-09-03

18

Soybean Oil Derivatives for Fuel and Chemical Feedstocks  

SciTech Connect

Plant based sources of hydrocarbons are being considered as alternatives to petrochemicals because of the need to conserve petroleum resources for reasons of national security and climate change. Changes in fuel formulations to include ethanol from corn sugar and methyl esters from soybean oil are examples of this policy in the United States and elsewhere. Replacements for commodity chemicals are also being considered, as this value stream represents much of the profit for the oil industry and one that would be affected by shortages in oil or other fossil fuels. While the discovery of large amounts of natural gas associated with oil shale deposits has abated this concern, research into bio-based feedstock materials continues. In particular, this chapter reviews a literature on the conversion of bio-based extracts to hydrocarbons for fuels and for building block commodity chemicals, with a focus on soybean derived products. Conversion of methyl esters from soybean triglycerides for replacement of diesel fuel is an active area of research; however, the focus of this chapter will not reside with esterification or transesterification, except has a means to provide materials for the production of hydrocarbons for fuels or chemical feedstocks. Methyl ester content in vehicle fuel is limited by a number of factors, including the performance in cold weather, the effect of oxygen content on engine components particularly in the case of older engines, shelf-life, and higher NOx emissions from engines that are not tuned to handle the handle the enhanced pre-ignition conditions of methyl ester combustion [1]. These factors have led to interest in synthesizing a hydrocarbon fuel from methyl esters, one that will maintain the cetane number but will achieve better performance in an automobile: enhanced mixing, injection, and combustion, and reduce downstream issues such as emissions and upstream issues such as fuel preparation and transportation. Various catalytic pathways from oxygenated precursor to hydrocarbon will be considered in the review: pyrolysis [2], deoxygenation and hydrogenation [3, 4], and hydrotreatment [5]. The focus of many of these studies has been production of fuels that are miscible or fungible with petroleum products, e.g., the work published by the group of Daniel Resasco at U. Oklahoma [6]. Much of the published literature focuses on simpler chemical representatives of the methyl esters form soybean oil; but these results are directly applicable to the production of chemical feedstocks, such as ethylbenzene that can be used for a variety of products: polymers, solvent, and reagent [3]. Although many chemical pathways have been demonstrated in the laboratory, the scale-up to handle quantities of bio-derived material presents a number of challenges in comparison with petroleum refining. These range from additional transportation costs because of distributed feedstock production to catalyst cost and regeneration. Other chapters in the book appear to address the cultivation and harvesting of soybeans and production of oil, so these areas will not be dealt with directly in this chapter except as they may relate to chemical changes in the feedstock material. However, the feasibility of the production of hydrocarbons from soybean triglycerides or methyl esters derived from these triglycerides will be considered, along with remaining technical hurdles before soybeans can make a significant contribution to the hydrocarbon economy.

McFarlane, Joanna [ORNL

2013-01-01

19

Scedosporium prolificans Osteomyelitis in an Immunocompetent Child Treated with Voriconazole and Caspofungin, as Well as Locally Applied Polyhexamethylene Biguanide  

Microsoft Academic Search

Scedosporium species are increasingly isolated from immunocompromised and immunocompetent patients. Unfortunately, Scedosporium infections are generally resistant to amphotericin B, and Scedosporium prolificans strains are particularly resistant to the antifungal agents now in use. We report here on an immunocompetent child with S. prolificans-associated osteomyelitis successfully treated with debridement, local irrigation with polyhexamethylene biguanide, and the systemic administration of voriconazole and

William J. Steinbach; Wiley A. Schell; Jackie L. Miller; John R. Perfect

2003-01-01

20

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

PubMed

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

Dilamian, M; Montazer, M; Masoumi, J

2013-01-28

21

Miltefosine and polyhexamethylene biguanide: a new drug combination for the treatment of Acanthamoeba keratitis.  

PubMed

PURPOSE: In this study, a series of compounds - miltefosine (MLT), polyhexamethylene biguanide (PHMB), chlorhexidine (CHX), and propamidine isethionate (PI) - and combinations of the latter three agents with miltefosine were prepared and used in a rat model for the topical treatment of Acanthamoeba keratitis. METHODS: The corneas of rats were infected with Acanthamoeba hatchetti. On the fifth day, all corneas were microscopically examined in order to determine the grade of infections. Nine groups were then prepared: MLT (65.12 ?g/mL); CHX (0.02%); PHMB (0.02%), PI (0.1%), MLT plus CHX, MLT plus PHMB; MLT plus PI; infected control; and a non-infected control group. The treatment was continued for 28 days. After the treatment, the corneas were excised and used for Acanthamoeba culture to investigate the presence of Acanthamoeba growth. For the determination of cytotoxicity of the drugs on L929 cells, colorimetric assays were performed. RESULTS: The best treatment results were obtained from the PHMB plus MLT group: the ratio of fully recovered eyes was 28.4%. It was proven that the MLT-PHMB combination yielded the highest anti-acanthamoebal activity in that approximately 86% of the eyes were cleared from amoebae. The cytotoxicity values of the MLT and the control groups were compared with other groups, and found to be statistically different (p<0.05). CONCLUSION: This in vivo study demonstrates that a MLT-PHMB combination is highly effective for the treatment of AK. PMID:23601234

Polat, Zubeyde A; Walochnik, Julia; Obwaller, Andreas; Vural, Ayse; Dursun, Ayhan; Arici, Mustafa K

2013-04-22

22

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

PubMed Central

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.

Lebedev, A V; Rezvukhin, A I

1984-01-01

23

The Evaluation of Polyhexamethylene Biguanide (PHMB) as a Disinfectant for Adenovirus  

PubMed Central

Purpose Swimming pools can be a vector for transmission of adenovirus ocular infections. Polyhexamethylene biguanide (PHMB) is a disinfectant used in swimming pools and hot tubs. The current study determined whether PHMB is an effective disinfectant against ocular adenovirus serotypes at a concentration used to disinfect swimming pools and hot tubs. Methods The direct disinfecting activity of PHMB was determined in triplicate assays by incubating nine human adenovirus types (1, 2, 3, 4, 5, 7a, 8, 19, and 37) with 50 and 0 PPM (µg/ml) of PHMB for 24 hours at room temperature, to simulate swimming pool temperatures, or 40°C, to simulate hot tub temperatures. Plaque assays determined adenovirus titers after incubation. Titers were Log10 converted and mean ± standard deviation Log10 reductions from controls were calculated. Virucidal (greater than 99.9%) decreases in mean adenovirus titers after PHMB treatment were determined for each adenovirus type and temperature tested. Results At room temperature, 50 PPM of PHMB produced mean reductions in titers less than 1 Log10 for all adenovirus types tested. At 40°C, 50 PPM of PHMB produced mean reductions in titers less than 1 Log10 for two adenovirus types and greater than 1 Log10, but less than 3 Log10, for seven of nine adenovirus types. Conclusions 50 PPM of PHMB was not virucidal against adenovirus at temperatures consistent with swimming pools or hot tubs. Clinical Relevance Recreational water maintained and sanitized with PHMB has the potential to serve as a vector for the transmission of ocular adenovirus infections.

Romanowski, Eric G.; Yates, Kathleen A.; O'Connor, Katherine E.; Mah, Francis S.; Shanks, Robert M. Q.; Kowalski, Regis P.

2013-01-01

24

Effects of insulin, biguanide antihyperglycaemic agents and beta-adrenergic agonists on pathways of myocardial proteolysis.  

PubMed Central

Pathways of bulk protein degradation controlled by insulin and isoprenaline (isoproterenol) were distinguished in Langendorff-perfused rat hearts. Proteins were biosynthetically labelled in vitro with [3H]leucine, followed by addition of 2 mM non-radioactive leucine to competitively prevent reincorporation. Rapidly degraded proteins were eliminated during a 3 h preliminary perfusion period without insulin. One third of bulk myocardial protein degradation was inhibited by isoprenaline as described previously. An insulin concentration of 5 nM maximally inhibited proteolysis, beginning within 2 min. Inhibition reached 32% within 1.25 h and 35% after 1.5 h. The minimum effective insulin concentration was approx. 10-50 pM, which caused 10-20% inhibition. Following 3 h of perfusion without insulin, the lysosomal inhibitor, chloroquine (30 microM), inhibited 38% of bulk degradation. The 35% proteolytic inhibition caused by insulin was followed by very little further inhibition on subsequent concurrent infusion of chloroquine, i.e. the inhibitory effects of insulin and chloroquine were not additive. In contrast, prior inhibition of lysosomal proteolysis by insulin or chloroquine did not prevent the subsequent additive inhibition caused by isoprenaline. Insulin and beta-agonists additively inhibited approx. two-thirds of bulk degradation. The biguanide antihyperglycaemic agent phenformin (2 microM) inhibited 35% of bulk degradation, beginning at 2 min and reaching a near maximum at approx. 1.25-1.5 h. Following inhibition of proteolysis with phenformin (20 microM), subsequent infusion of chloroquine (30 microM) produced only a slight additional inhibition. Following inhibition of 35% of degradation by 1.5 h of perfusion with insulin (5 nM), subsequent exposure to phenformin (2 microM) produced only a slight additional inhibition which did not exceed 38% of basal proteolysis. Thus insulin and phenformin both inhibit lysosomal proteolysis; however, the adrenergic-responsive pathway is distinct.

Thorne, D P; Lockwood, T D

1990-01-01

25

CHEMICAL PATHWAYS FOR THE PREPARATION OF LABELED DERIVATIVES OF DIHYDROXYACETONE  

Microsoft Academic Search

The object of this investigation was to devise a chemical synthesis of ; dihydroxyacetone phosphate in a manner that could produce a product uniquely ; labeled at carbon atoms 1, 2, or 3. This compound would be useful for the ; enzymatic synthesis of D-fructose-1,6-diphosphate uniquely labeled with C¹⁴ ; in any position, a specificity of labeling that has never

Weinswig

1962-01-01

26

Scedosporium prolificans Osteomyelitis in an Immunocompetent Child Treated with Voriconazole and Caspofungin, as Well as Locally Applied Polyhexamethylene Biguanide  

PubMed Central

Scedosporium species are increasingly isolated from immunocompromised and immunocompetent patients. Unfortunately, Scedosporium infections are generally resistant to amphotericin B, and Scedosporium prolificans strains are particularly resistant to the antifungal agents now in use. We report here on an immunocompetent child with S. prolificans-associated osteomyelitis successfully treated with debridement, local irrigation with polyhexamethylene biguanide, and the systemic administration of voriconazole and caspofungin despite poor in vitro activity of voriconazole alone against the isolate. We also review the treatments and outcomes of 28 reported cases of osteomyelitis or septic arthritis caused by Scedosporium species in immunocompetent patients.

Steinbach, William J.; Schell, Wiley A.; Miller, Jackie L.; Perfect, John R.

2003-01-01

27

Evaluation of xanthine derivatives in chocolate – nutritional and chemical aspects  

Microsoft Academic Search

Organic substances containing nitrogen are widespread throughout the whole of the natural world. Also included amongst these\\u000a are the methylxanthine derivatives caffeine, theobromine and theophylline. These are very closely related and are to be found\\u000a in extremely varying contents in different plants. Because of their pharmacological effect, which is fundamentally of a stimulative\\u000a nature, methylxanthines have been significant since time

Reinhard Matissek

1997-01-01

28

Functionalisation and chemical characterisation of cellulose-derived carbon aerogels  

Microsoft Academic Search

A series of nitrogen- and oxygen-functionalised carbon aerogels was produced from a carbon aerogel derived from cellulose acetate. Samples were oxidised by H2O2 or HNO3 and\\/or enriched in nitrogen by reaction with gaseous ammonia or co-heating of the carbon aerogel and melamine. Porosity variations and morphology were monitored using N2 adsorption and helium pycnometry. The surface chemistry was characterised by

Bartosz Grzyb; Claudia Hildenbrand; Sandrine Berthon-Fabry; Dominique Bégin; Nathalie Job; Arnaud Rigacci; Patrick Achard

2010-01-01

29

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

Microsoft Academic Search

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

Michael Murray

2012-01-01

30

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

Microsoft Academic Search

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

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

2007-01-01

31

Conical intersection seams in polyenes derived from their chemical composition  

SciTech Connect

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.

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

2012-08-21

32

Chemical encapsulation of rocuronium by synthetic cyclodextrin derivatives: reversal of neuromuscular block in anaesthetized Rhesus monkeys  

Microsoft Academic Search

BACKGROUND: At present, reversal of neuromuscular block induced by steroidal neuromuscular blocking agents (NMBAs) is achieved by administration of cholinesterase inhibitors. Chemical encapsulation of steroidal NMBAs, such as rocuronium, by a cyclodextrin is a new concept in neuromuscular block reversal. The present study evaluates the capacity of nine synthetic cyclodextrin derivatives (Org 25288, Org 25289, Org 25467, Org 25168, Org

H. D. de Boer; J. van Egmond; F. van de Pol; A. Bom; L. H. D. J. Booij

2006-01-01

33

Synthesis and applications of 2-aminopyrimidine derivatives as key intermediates in chemical synthesis of biomolecules  

NASA Astrophysics Data System (ADS)

Published data on the main approaches to the formation of the heterocyclic 2-aminopyrimidine system, which is one of important pharmacophores responsible for the biological properties of its derivatives, are described systematically. Main chemical transformations of functionalized 2-aminopyrimidines and their application in the synthesis of modern pharmaceuticals are considered.

Koroleva, Elena V.; Gusak, K. N.; Ignatovich, Zh V.

2010-10-01

34

Correlation between chemical structure and rodent repellency of benzoic acid derivatives  

USGS Publications Warehouse

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.

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

1965-01-01

35

Correlation Between Dielectric Properties and Chemical Changes in Soybean Oil Derivatives  

Microsoft Academic Search

Dielectric properties of soybean oil derivatives were measured at frequency bands from 10 to 10 Hz at different temperatures. Relaxation times ?, activation enthalpies ?H, and entropy changes ?S for dielectric relaxation were calculated and related to the chemical changes of the samples. It was found that dielectric properties can be used in differentiating between epoxidized and nonepoxidized oils, and

I. Z. Selim

1997-01-01

36

Surface work function of chemically derived graphene: A first-principles study  

NASA Astrophysics Data System (ADS)

Using first-principles calculations within the framework of density-functional theory, we systematically study the modulation effect of chemical decoration including hydrogenation, fluorination, and oxidization on the surface work function of graphene. The chemical decoration is effective approach to modulate the surface work function, which expands the space to design diverse nano-devices based on graphene. Moreover, we also find some un-expectation chemically decorated cases which do not follow the traditional rule of "electronegative (electropositive) adsorbates, which increase (decrease) the work function of the surface". Such a phenomenon is mainly derived from the charge redistribution induced by the bonding process between adsorbates and carbon atoms along with the chemical decoration.

Jiao, N.; He, Chaoyu; Zhou, P.; Zhang, C. X.; Xiao, H. P.; Sun, L. Z.

2013-10-01

37

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

Microsoft Academic Search

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

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

2011-01-01

38

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

Microsoft Academic Search

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

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

1990-01-01

39

Differential response to chemically altered polyethylene by activated mature human monocyte-derived macrophages  

Microsoft Academic Search

Macrophages and polyethylene (PE) particulate are currently recognized as being the two common denominators in the development of chronic inflammation, periprosthetic osteolysis, and subsequent implant failure. In this study, the effect of PE particulate surface chemistry on mature human monocyte-derived macrophage (MDM) function was investigated. Virgin high-density PE (HDPE: 4–10?m) and HDPE oxidized by irradiation, thermal and chemical treatment were

S Xing; J. P Santerre; R. S Labow; E. L Boynton

2002-01-01

40

Comparative Study of Risk Assessment Approaches Based on Different Methods for Deriving DNEL and PNEC of Chemical Mixtures  

Microsoft Academic Search

\\u000a Most living organisms are actually exposed to chemical mixtures rather than individual substances. But current chemical risk\\u000a assessment frequently focuses on the single chemical substances. The European Union presented some methods in the draft technical\\u000a guidance notes for deriving DNEL (Derived No Effect Level) and PNEC (Predicted No Effect Concentration) for risk assessment\\u000a of mixtures. This case study shows that

Jongwoon Kim; Sanghun Kim; Gabriele E. Schaumann

2010-01-01

41

A pathwise derivative approach to the computation of parameter sensitivities in discrete stochastic chemical systems  

PubMed Central

Characterizing the sensitivity to infinitesimally small perturbations in parameters is a powerful tool for the analysis, modeling, and design of chemical reaction networks. Sensitivity analysis of networks modeled using stochastic chemical kinetics, in which a probabilistic description is used to characterize the inherent randomness of the system, is commonly performed using Monte Carlo methods. Monte Carlo methods require large numbers of stochastic simulations in order to generate accurate statistics, which is usually computationally demanding or in some cases altogether impractical due to the overwhelming computational cost. In this work, we address this problem by presenting the regularized pathwise derivative method for efficient sensitivity analysis. By considering a regularized sensitivity problem and using the random time change description for Markov processes, we are able to construct a sensitivity estimator based on pathwise differentiation (also known as infinitesimal perturbation analysis) that is valid for many problems in stochastic chemical kinetics. The theoretical justification for the method is discussed, and a numerical algorithm is provided to permit straightforward implementation of the method. We show using numerical examples that the new regularized pathwise derivative method (1) is able to accurately estimate the sensitivities for many realistic problems and path functionals, and (2) in many cases outperforms alternative sensitivity methods, including the Girsanov likelihood ratio estimator and common reaction path finite difference method. In fact, we observe that the variance reduction using the regularized pathwise derivative method can be as large as ten orders of magnitude in certain cases, permitting much more efficient sensitivity analysis than is possible using other methods.

Sheppard, Patrick W.; Rathinam, Muruhan; Khammash, Mustafa

2012-01-01

42

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

PubMed

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

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

2011-07-21

43

Evaluation of hepatotoxicity of chemicals using hepatic progenitor and hepatocyte-like cells derived from mouse embryonic stem cells: effect of chemicals on ESC-derived hepatocyte differentiation.  

PubMed

Embryonic stem cell testing is an alternative model system to assess drug and chemical toxicities because of its similar developmental characteristics with in vivo embryogenesis and organogenesis. This study evaluated the toxicity of chemicals at specific developmental stages of mouse embryonic stem cell (ESC)-derived hepatic differentiation; hepatic progenitor cells (HPCs), and hepatocyte-like cells (HCs). The toxic effects of carbon tetrachloride (CCl(4)), 5-fluorouracil (5-FU), and arsanilic acid (Ars) were evaluated by measuring the expressions of Cytokeratin (CK18) and GATA binding protein 4 (GATA-4) and the activities of aspartate transaminase (AST), lactate dehydrogenase (LDH), and alkaline phosphatase (ALP) during the hepatic differentiation process. Non-toxic doses of three chemicals at a range of 25 to 500 ?M for CCl(4), 12.5 to 800 nM for 5-FU and 6.25 to 400 mM for Ars were treated. In the CCl(4)-treated group, significant decreases (P?chemicals were significantly increased (P?derived HPCs and HCs could provide useful information on chemical toxicity during the hepatic differentiation process and could be a useful model system for assessing chemical hepatotoxicity. PMID:23108452

Kang, Seok-Jin; Jeong, Sang-Hee; Kim, Eun-Joo; Cho, Joon-Hyoung; Park, Young-Il; Park, Sung-Won; Shin, Hyo-Sook; Son, Seong-Wan; Kang, Hwan-Goo

2012-10-30

44

Microbial production of fatty-acid-derived fuels and chemicals from plant biomass.  

PubMed

Increasing energy costs and environmental concerns have emphasized the need to produce sustainable renewable fuels and chemicals. Major efforts to this end are focused on the microbial production of high-energy fuels by cost-effective 'consolidated bioprocesses'. Fatty acids are composed of long alkyl chains and represent nature's 'petroleum', being a primary metabolite used by cells for both chemical and energy storage functions. These energy-rich molecules are today isolated from plant and animal oils for a diverse set of products ranging from fuels to oleochemicals. A more scalable, controllable and economic route to this important class of chemicals would be through the microbial conversion of renewable feedstocks, such as biomass-derived carbohydrates. Here we demonstrate the engineering of Escherichia coli to produce structurally tailored fatty esters (biodiesel), fatty alcohols, and waxes directly from simple sugars. Furthermore, we show engineering of the biodiesel-producing cells to express hemicellulases, a step towards producing these compounds directly from hemicellulose, a major component of plant-derived biomass. PMID:20111002

Steen, Eric J; Kang, Yisheng; Bokinsky, Gregory; Hu, Zhihao; Schirmer, Andreas; McClure, Amy; Del Cardayre, Stephen B; Keasling, Jay D

2010-01-28

45

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

NASA Astrophysics Data System (ADS)

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

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

2013-04-01

46

A pathwise derivative approach to the computation of parameter sensitivities in discrete stochastic chemical systems.  

PubMed

Characterizing the sensitivity to infinitesimally small perturbations in parameters is a powerful tool for the analysis, modeling, and design of chemical reaction networks. Sensitivity analysis of networks modeled using stochastic chemical kinetics, in which a probabilistic description is used to characterize the inherent randomness of the system, is commonly performed using Monte Carlo methods. Monte Carlo methods require large numbers of stochastic simulations in order to generate accurate statistics, which is usually computationally demanding or in some cases altogether impractical due to the overwhelming computational cost. In this work, we address this problem by presenting the regularized pathwise derivative method for efficient sensitivity analysis. By considering a regularized sensitivity problem and using the random time change description for Markov processes, we are able to construct a sensitivity estimator based on pathwise differentiation (also known as infinitesimal perturbation analysis) that is valid for many problems in stochastic chemical kinetics. The theoretical justification for the method is discussed, and a numerical algorithm is provided to permit straightforward implementation of the method. We show using numerical examples that the new regularized pathwise derivative method (1) is able to accurately estimate the sensitivities for many realistic problems and path functionals, and (2) in many cases outperforms alternative sensitivity methods, including the Girsanov likelihood ratio estimator and common reaction path finite difference method. In fact, we observe that the variance reduction using the regularized pathwise derivative method can be as large as ten orders of magnitude in certain cases, permitting much more efficient sensitivity analysis than is possible using other methods. PMID:22280752

Sheppard, Patrick W; Rathinam, Muruhan; Khammash, Mustafa

2012-01-21

47

Chemically defined conditions for human iPS cell derivation and culture  

PubMed Central

We reexamine the individual components for human ES and iPS cell culture, and formulate a cell culture system in which all protein reagents for liquid media, attachment surfaces, and splitting are chemically defined. A major improvement is the lack of a serum albumin component, as variations in either animal or human sourced albumin batches have previously plagued human ES and iPS cell culture with inconsistencies. Using this new medium (E8) and vitronectin-coated surfaces, we demonstrate improved derivation efficiencies of vector-free human iPS cells with an episomal approach. This simplified E8 medium should facilitate both the research use and clinical applications of human ES and iPS cells and their derivatives, and should be applicable to other reprogramming methods.

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

2011-01-01

48

Accumulation of plastic-derived chemicals in tissues of seabirds ingesting marine plastics.  

PubMed

We analyzed polybrominated diphenyl ethers (PBDEs) in abdominal adipose of oceanic seabirds (short-tailed shearwaters, Puffinus tenuirostris) collected in northern North Pacific Ocean. In 3 of 12 birds, we detected higher-brominated congeners (viz., BDE209 and BDE183), which are not present in the natural prey (pelagic fish) of the birds. The same compounds were present in plastic found in the stomachs of the 3 birds. These data suggested the transfer of plastic-derived chemicals from ingested plastics to the tissues of marine-based organisms. PMID:23298431

Tanaka, Kosuke; Takada, Hideshige; Yamashita, Rei; Mizukawa, Kaoruko; Fukuwaka, Masa-aki; Watanuki, Yutaka

2013-01-05

49

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

PubMed Central

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

2012-01-01

50

Combined physical-chemical and aerobic biological treatments of wastewater derived from sauce manufacturing.  

PubMed

The viability of an integrated coagulation-flocculation and aerobic treatment for purifying wastewater derived from a sauce manufacturing industry was evaluated. The best coagulation-flocculation results were obtained at alkaline pH, showing the greatest turbidity removal efficiency (greater than 90%) and a total chemical oxygen demand (COD) removal of approximately 80%, Additionally, experiments at alkaline pH reduce the reagent requirements (coagulant concentration of 0.4 mL/L and flocculant concentration of 4.0 mL/L) providing a consequent economic benefit as compared to experiments at neutral and acidic pH. Another set of experiments was conducted in a sequencing batch reactor to evaluate the aerobic biodegradability of the remnant dissolved organic matter. The effluent from the physical-chemical pre-treatment at alkaline pH again showed the highest biodegradability (76%), with a global COD total removal of 98%. The results showed that the combination of both techniques could be a viable alternative to efficiently treat wastewater derived from sauce manufacturing. PMID:23697239

Martín, M A; González, I; Siles, J A; Berrios, M; Martín, A

2013-04-01

51

Chemical shift assignment and structural plasticity of a HIV fusion peptide derivative in dodecylphosphocholine micelles  

PubMed Central

Summary A “HFPK3” peptide containing the 23 residues of the human immunodeficiency virus (HIV) fusion peptide (HFP) plus three non-native C-terminal lysines was studied in dodecylphosphocholine (DPC) micelles with 2D 1H NMR spectroscopy. The HFP is at the N-terminus of the gp41 fusion protein and plays an important role in fusing viral and target cell membranes which is a critical step in viral infection. Unlike HFP, HFPK3 is monomeric in detergent-free buffered aqueous solution which may be a useful property for functional and structural studies. H? chemical shifts indicated that DPC-associated HFPK3 was predominantly helical from I4 to L12. In addition to the highest-intensity crosspeaks used for the first chemical shift assignment (denoted I), there were additional crosspeaks whose intensities were ~10% of those used for assignment I. A second assignment (II) for residues G5 to L12 as well as a few other residues was derived from these lower-intensity crosspeaks. Relative to the I shifts, the II shifts were different by 0.01–0.23 ppm with the largest differences observed for HN. Comparison of the shifts of DPC-associated HFPK3 with those of detergent-associated HFP and HFP derivatives provided information about peptide structures and locations in micelles.

Gabrys, Charles M.; Weliky, David P.

2008-01-01

52

[Spectral analysis of dissolved organic matter derived from rice straw after chemical treatment].  

PubMed

Fourier transform infrared spectroscopy (FTIR), ultraviolet spectroscopy (UV), and nuclear magnetic resonance spectroscopy (NMR) were used to study the chemical composition of Dissolved Organic Matter (DOM) derived from rice straw in the hydrolysis process with a dilute complex acid solution. The results obtained are as follows. FTIR spectra could indicate the changes of DOM during the hydrolysis process of rice straw. With the progress of rice straw hydrolysis, methyl, methylene, aromatic compounds and carbohydrates decreased, most of aliphatic compounds were oxidized to CO2 and H2O, and others were turned into carbonates. Most of the organic silicon was hydrolyzed into inorganic silicon. The proteins, amino acids and other nitrogen were hydrolyzed to NH4+. All the recalcitrant fractions of rice straw, such as hemi-cellulose, cellulose and silicon sharply decreased during the process of chemical treatment. The results obtained in this paper proposed that the changes of DOM of rice straw in the hydrolysis could be an indication in the changes of chemical composition of rice straw during the hydrolyzation, and FTIR, UV and NMR were good methods to study the changes in the structure of organic compounds. PMID:15856553

Shen, Qi-Rong; Xu, Yong; Yang, Hong; Zhou, Li-Xiang; Yu, Qing; Zhou, Zhi-Ping

2005-02-01

53

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

PubMed Central

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

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

1992-01-01

54

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

SciTech Connect

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.

David C. Dayton

2010-03-24

55

Deriving Toxicity Values for Organophosphate Nerve Agents: A Position Paper in Support of the Procedures and Rationale for Deriving Oral RfDs for Chemical Warfare Nerve Agents  

Microsoft Academic Search

During the process of deriving oral Reference Dose (RfDs) values for chemical warfare agents, several issues arose regarding the identification of adverse effect levels and the application of uncertainty factors. For those agents that function as cholinesterase inhibitors (e.g., agents VX, GA, GB, and GD), these issues included the following: (1) Is the endpoint of blood cholinesterase inhibition an indicator

Robert A. Young; Dennis M. Opresko; Annetta P. Watson; Robert H. Ross; Joe King; Harlal Choudhury

1999-01-01

56

High performance In2O3 thin film transistors using chemically derived aluminum oxide dielectric  

NASA Astrophysics Data System (ADS)

We report high performance solution-deposited indium oxide thin film transistors with field-effect mobility of 127 cm2/Vs and an Ion/Ioff ratio of 106. This excellent performance is achieved by controlling the hydroxyl group content in chemically derived aluminum oxide (AlOx) thin-film dielectrics. The AlOx films annealed in the temperature range of 250-350 °C showed higher amount of Al-OH groups compared to the films annealed at 500 °C, and correspondingly higher mobility. It is proposed that the presence of Al-OH groups at the AlOx surface facilitates unintentional Al-doping and efficient oxidation of the indium oxide channel layer, leading to improved device performance.

Nayak, Pradipta K.; Hedhili, M. N.; Cha, Dongkyu; Alshareef, H. N.

2013-07-01

57

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

SciTech Connect

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.

Quinn, M.M.; Wegman, D.H.; Greaves, I.A.; Hammond, S.K.; Ellenbecker, M.J.; Spark, R.F.; Smith, E.R. (Univ. of Massachusetts Medical School, Worcester (USA))

1990-01-01

58

Responses of human adipose-derived mesenchymal stem cells to chemical microenvironment of the intervertebral disc  

PubMed Central

Background Human adipose-derived mesenchymal stem cells (ADMSCs) may be ideal source of cells for intervertebral disc (IVD) regeneration, but the harsh chemical microenvironment of IVD may significantly influence the biological and metabolic vitality of ADMSCs and impair their repair potential. This study aimed to investigate the viability, proliferation and the expression of main matrix proteins of ADMSCs in the chemical microenvironment of IVD under normal and degeneration conditions. Methods ADMSCs were harvested from young (aged 8-12 years, n = 6) and mature (aged 33-42 years, n = 6) male donors and cultured under standard condition and IVD-like conditions (low glucose, acidity, high osmolarity, and combined conditions) for 2 weeks. Cell viability was measured by annexin V-FITC and PI staining and cell proliferation was measured by MTT assay. The expression of aggrecan and collagen-I was detected by real-time quantitative polymerase chain reaction and Western blot analysis. Results IVD-like glucose condition slightly inhibited cell viability, but increased the expression of aggrecan. In contrast, IVD-like osmolarity, acidity and the combined conditions inhibited cell viability and proliferation and the expression of aggrecan and collagen-I. ADMSCs from young and mature donors exhibited similar responses to the chemical microenvironments of IVD. Conclusion IVD-like low glucose is a positive factor but IVD-like high osmolarity and low pH are deleterious factors that affect the survival and biological behaviors of ADMSCs. These findings may promote the translational research of ADMSCs in IVD regeneration for the treatment of low back pain.

2012-01-01

59

Chemical nature of implant-derived titanium(IV) ions in synovial fluid  

SciTech Connect

Previous investigations have indicated a deleterious leakage of Ti(III) and/or Ti(IV) species from Ti-Al-V alloy joint prostheses into adjacent tissue, synovium or synovial fluid (SF) in vivo. In view of the importance of the particular chemical nature of such complexes in determining their biological activity, we have employed high field proton ({sup 1}H) NMR spectroscopy to 'speciate' Ti(IV) in inflammatory SF. Treatment of osteoarthritic SF samples with increasing concentrations of Ti(IV) (0.10-1.03 mM [TiO(C{sub 2}O{sub 4}){sub 2}]{sup 2-}) gave rise to a specific broadening of the citrate proton resonances, indicating that this bioavailable oxygen-donor ligand plays an important role in complexing implant-derived Ti(IV). {sup 1}H NMR analysis of Ti(IV)-loaded SF samples subsequently treated with a large excess of ascorbate (0.05 M) showed that this added Ti(IV) chelator was only poorly effective in removing this metal ion from Ti(IV)-citrate/Ti(IV)-oxycitrate complexes. The results obtained here provide evidence for complexation of the low-molecular-mass (non-protein-bound) fraction of implant-derived Ti(IV) by citrate in vivo.

Silwood, Christopher J.L. [Department of Applied Science, Faculty of Engineering, Science and the Built Environment, London South Bank University, 103 Borough Road, London SE1 0AA (United Kingdom); Grootveld, Martin [Department of Applied Science, Faculty of Engineering, Science and the Built Environment, London South Bank University, 103 Borough Road, London SE1 0AA (United Kingdom)]. E-mail: grootvm@lsbu.ac.uk

2005-05-13

60

Iodinated derivatives of vasoactive intestinal peptide (VIP), PHI and PHM: purification, chemical characterization and biological activity  

SciTech Connect

The iodination of vasoactive intestinal peptide (VIP) was studied, using a variety of enzymatic and chemical iodination methods. Reversed phase high performance liquid chromatography (HPLC) was used to purify the reaction products. The lactoperoxidase-glucose oxidase method gave excellent results in terms of reproducibility, iodine incorporation, and yield of the non-oxidized products (Tyr(I)10)VIP and (Tyr(I)22)VIP, and was used to prepare both /sup 125/I and /sup 127/I labelled derivatives. In both cases, direct application to HPLC and a single column system were used. Although the oxidized peptides (Tyr(I)10,Met(O)17)VIP and (Tyr(I)22,Met(O)17)VIP could be generated to varying degrees directly by iodination of VIP, these were most conveniently prepared by iodination of (Met(O)17)VIP. Iodinated derivatives of the homologous peptides PHI and PHM were likewise prepared by rapid, one-step HPLC procedures. The site and degree of iodination were determined by HPLC peptide mapping of tryptic digests and amino acid analyses, and in the case of (Tyr(I)10)VIP also by sequencing. The vasorelaxant activities of the iodinated peptides in bovine cerebral artery preparations did not differ significantly from those of the corresponding noniodinated peptides, with the exception of (Tyr(I)10,Met(O)17)VIP and (Tyr(I)22,Met(O)17)VIP which, unlike (Met(O)17)VIP itself, had slightly lower potency than VIP.

McMaster, D.; Suzuki, Y.; Rorstad, O.; Lederis, K.

1987-07-01

61

The chemical characterization and instability of shale derived middle distillate fuels  

SciTech Connect

Changes in fuel properties with time in storage have been a continuing problem in the use of shale-derived middle distillate fuels. The storage stability of middle distillate fuels is usually defined in terms of the formation of sediment, gum, color, and peroxides. A shale-derived fuel of marginal stability has been used as a source of nitrogen-rich polar extracts. These polar nitrogen heteroatonis were isolated by mild acid extraction followed by silica gel adsorption and were identified by combined capillary column GC/MS. Alkyl substituted pyridines were the prevalent class of compounds present. Other nitrogen functional groups present included the alkyl substituted: tetrahydroquinolines, quinolines, indoles, and carbazoles. This fuel was also analyzed for the metal ions content by ICP. The effect of adding these shale extract fractions as dopants to a stable shale diesel fuel were examined in terms of sediment formation, and peroxide number under accelerated storage stability test conditions. We have developed a 16 hour test method that predict accurately fuel behavior over a two year period. The activities of the extracts in inducing fuel instability were correlated with their chemical composition and will be reported.

Mushrush, G.W.; Mose, D.G. [George Mason Univ., Fairfax, VA (United States)

1996-09-01

62

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

PubMed Central

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.

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

63

Chemical synthesis and formulation design of a PEGylated vasoactive intestinal peptide derivative with improved metabolic stability.  

PubMed

The present study aimed to design a PEGylated VIP derivative, [Arg(15, 20, 21), Leu(17)]-VIP-GRR (IK312532), with improved metabolic stability, and develop its respirable powder (RP) formulation for inhalation therapy. IK312532 was chemically conjugated with PEG (5 kDa, P5K), the physicochemical and biochemical properties of which were characterized by CD spectral analysis, binding assays, and metabolic stability. CD spectral analysis demonstrated that PEG conjugation had no impact on the conformational structure of IK312532. Although the receptor-binding activity of IK312532/P5K (IC??: 82 nM) was estimated to be ca. 30-fold less than that of IK312532 (IC??: 2.8 nM), the metabolic stability of IK312532/P5K was highly improved. The IK312532/P5K was jet-milled and blended with lactose carrier particles to provide RP formulation of IK312532/P5K (IK312532/P5K-RP). In vitro inhalation performance and in vivo pharmacological effects of the IK312532/P5K-RP in antigen-sensitized rats were also evaluated. In cascade impactor analyses, fine particle fraction of IK312532/P5K-RP was calculated to be ca. 37%. Insufflation of IK312532/P5K-RP (150 ?g of IK312532/P5K) in antigen-sensitized rats resulted in marked attenuation of inflammatory events, as evidenced by significant decreases in inflammatory biomarkers and granulocyte recruitment in pulmonary tissue 24h after the antigen challenge. From these findings, PEGylation of a VIP derivative, as well as its strategic application to the RP formulation, may be a viable approach to improve its therapeutic potential for the treatment of airway inflammatory diseases. PMID:23608612

Onoue, Satomi; Matsui, Takuya; Kato, Masashi; Mizumoto, Takahiro; Liu, Baosheng; Liu, Liang; Karaki, Shin-ichiro; Kuwahara, Atsukazu; Yamada, Shizuo

2013-04-19

64

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

PubMed Central

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.

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

2006-01-01

65

Chemical Processing for Sol-Gel Derived Metal Oxide Thin Films using Supercritical Carbon Dioxide Fluid  

NASA Astrophysics Data System (ADS)

Chemical processing using supercritical carbon dioxide fluid (scCO2) was demonstrated for lowering processing temperature of sol-gel-derived metal oxide thin films. The film processing was performed in a hot-wall closed vessel filled with scCO2 fluid. Precursor films of titanium dioxide (TiO2) on soda-glass substrates prepared by sol-gel coating using Ti-alkoxide solution were converted to crystalline TiO2 (anatase) films successfully by the scCO2 treatment at a fluid pressure of 15 MPa and a substrate temperature of 300°C whereas no crystallization was occurred by conventional heat treatment at 400°C. XPS analysis indicated that the interface reaction related to Si element was suppressed successfully by scCO2 treatment at 300°C. These results suggest that the sol-gel synthesis using scCO2 fluid would be a cadidate for low-temperature processing of crystalline oxide films, which is more preferable than conventional techniques based on the heat treatment.

Asai, Y.; Narishige, S.; Fujioka, K.; Uchida, H.; Koda, S.

2011-10-01

66

Improving surface functional properties of tofu whey-derived peptides by chemical modification with fatty acids.  

PubMed

Effect of acylation with saturated fatty acids on surface functional properties of tofu whey-derived peptides was investigated. Tofu whey (TW) and soy proteins (7S, 11S, and acid-precipitated soy protein [APP]) were hydrolyzed by Protease M 'Amano' G, and resulting peptide mixtures were acylated with esterified fatty acids of different chain length (6C to 18C) to form a covalent linkage between the carboxyl group of fatty acid and the free amino groups of peptide. Acylation significantly (P < 0.05) increased emulsifying properties of 7S, 11S, and APP peptides independent of fatty acid chain length. Acylation decreased water binding capacity although oil binding capacity of acylated tofu whey ultra filtered fraction (UFTW < 3 kDa), 7S- and 11S-peptides were improved compared to native peptides. 7S peptides acylated with long chain fatty acids had shown significant higher surface hydrophobicity as in contrast with acylated UFTW < 3 kDa and APP peptides. Fluorescence spectra studies revealed structural conformation of acylated soy peptides as compared to native peptides. This study shows that chemical modification with fatty acids can further affect functional properties of soy proteins. PMID:22429318

Matemu, Athanasia Oswald; Katayama, Shigeru; Kayahara, Hisataka; Murasawa, Hisashi; Nakamura, Soichiro

2012-03-19

67

Photosensitization of skin fibroblasts and HeLa cells by three chlorin derivatives: Role of chemical structure and delivery vehicle  

Microsoft Academic Search

The chemical nature of the sensitizer and its selective uptake by malignant cells are decisive to choose an appropriate biocompatible carrier, able to preserve the photosensitizing characteristics of the dye. In this paper we demonstrate the photodynamic properties of three chlorins, derived from chlorophyll a, and the usefulness of liposomal carriers to design pharmaceutical formulations. The chlorins have been quantitatively

Fernando Postigo; M. Luisa Sagristá; M. Africa De Madariaga; Santi Nonell; Margarita Mora

2006-01-01

68

Comparative Study of Risk Assessment Approaches Based on Different Methods for Deriving DNEL and PNEC of Chemical Mixtures  

NASA Astrophysics Data System (ADS)

Most living organisms are actually exposed to chemical mixtures rather than individual substances. But current chemical risk assessment frequently focuses on the single chemical substances. The European Union presented some methods in the draft technical guidance notes for deriving DNEL (Derived No Effect Level) and PNEC (Predicted No Effect Concentration) for risk assessment of mixtures. This case study shows that the differences of DNELs and PNECs of mixtures (2 coating materials) based on two methods (KCC and CR methods) and explains why such differences are generated. The differences of DNELs and PNECs of the mixtures based on the two methods were estimated by 1.21 and 2.31 times respectively. Through the theoretical analysis on influence factors affecting DNEL and PNEC, it could be recognized that the difference between two methods can significantly increase in proportion to the number of substances having similar hazard and weight fraction.

Kim, Jongwoon; Kim, Sanghun; Schaumann, Gabriele E.

69

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

SciTech Connect

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

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

1996-09-01

70

Primary cilia: the chemical antenna regulating human adipose-derived stem cell osteogenesis.  

PubMed

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

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

2013-05-17

71

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

PubMed Central

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

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

2013-01-01

72

Capillary electrophoresis analysis of chemical warfare agent breakdown products I. Counterelectroosmotic separation of alkylphosphonic acids and their monoester derivatives  

Microsoft Academic Search

An analytical method has been developed for the analysis of chemical warfare agents by capillary zone electrophoresis (CZE). Sorbate anion has been selected as indirect UV-absorbing agent and decamethonium cation reduces the electroosmotic flow. The optimized electrolyte (5 mM sorbic acid, 0.1 mM decamethonium bromide pH 6) allows the simultaneous separation of alkylphosphonic acids and their monoester derivatives in less

J.-P. Mercier; Ph. Morin; M. Dreux; A. Tambute

1996-01-01

73

Effect of cholesterol or phospholipid incorporation on the chemical stability of the muramyldpeptide derivative B30MDP in mixed vesicles  

Microsoft Academic Search

Application of the muramyldipeptide derivative B30-MDP to liposomal vaccines will aid in the development of improved high immunogenicity vaccines. To give full play to the effectiveness of B30-MDP as a liposomal vaccine, it is important to evaluate the effect of cholesterol, dimyristoylphosphatidylcholine (DMPC) or distearoylphosphatidylcholine (DSPC) incorporation on the chemical stability of B30-MDP and physicochemical properties of B30-MDP\\/lipid mixed vesicles

S. Ando; H. Tsuge; T. Mayumi

1996-01-01

74

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

PubMed

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

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

2013-01-24

75

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

NASA Astrophysics Data System (ADS)

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.

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

2013-01-01

76

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

PubMed Central

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.

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

2013-01-01

77

Chemical Incident Simulator: A New Approach for Deriving Passive Defence Requirements.  

National Technical Information Service (NTIS)

The 'Chemical Incident Simulator' (CIS) - a chain of linked simulation models - simulates the dispersion, detector responses, effects of protective equipment, and human toxicological responses for many realistic scenarios. Operational behavior, like chang...

M. J. Linders C. A. van Beest P. Brasser L. F. Geers

2004-01-01

78

Synthesis of Renewable Fine-Chemical Building Blocks by Reductive Coupling between Furfural Derivatives and Terpenes.  

PubMed

Sugar and Spice…?: The use of renewable resources to produce fine chemicals is an underdeveloped area. A waste-free technology will be necessary to further convert platform chemicals, readily available from biomass. We show that furfurals, which can be obtained from C5 sugars, can be coupled with terpenes in up to 95?% yield through ruthenium-catalyzed reductive couplings developed by Krische et al. PMID:23857755

Nicklaus, Céline M; Minnaard, Adriaan J; Feringa, Ben L; de Vries, Johannes G

2013-07-15

79

Identification of Human-Derived Volatile Chemicals that Interfere with Attraction of Aedes aegypti Mosquitoes  

Microsoft Academic Search

It is known that human individuals show different levels of attractiveness to mosquitoes. In this study, we investigated the\\u000a chemical basis for low attractiveness. We recorded behaviors of Aedes aegypti toward the hands of human volunteers and toward the volatile chemicals produced by their bodies. Some individuals, and their\\u000a corresponding volatiles, elicited low upwind flight, relative attraction, and probing activity.

James G. Logan; Michael A. Birkett; Suzanne J. Clark; Stephen Powers; Nicola J. Seal; Lester J. Wadhams; John A. Pickett

2008-01-01

80

New N-aryloxy-phthalimide derivatives. Synthesis, physico-chemical properties, and QSPR studies  

Microsoft Academic Search

Starting from N-hydroxyphthalimide 1 and the reactive fluoro- or chloro-nitroaryl derivatives 2, 3 and 4a-e (2-chloro-3,5-dinitropyridine; 3, NBD-chloride; 4a, 1-fluoro-2,4-dinitrobenzene; 4b, picryl chloride; 4c, 4-chloro-3,5-dinitrobenzotrifluoride; 4d, 2-chloro-3,5- dinitrobenzotrifluoride; 4e, 4-chloro-3,5-dinitrobenzoic acid) the corresponding N-(2-nitroaryloxy)-phthalimide derivatives 5a-e, or 6 and 7 were obtained and characterized by IR, UV-Vis 1H-NMR and 13C-NMR spectroscopy. The TLC behavior and the hydrophobicity of these derivatives

Madalina Tudose; Florin D. Badea; Miron T. Caproiu; Adrian Beteringhe; Maria Maganu; Petre Ionita; Titus Constantinescu; Alexandru T. Balaban

2010-01-01

81

Chemical-microbiological synthesis of cryptomeridiol derivatives by Gliocladium roseum: semisynthesis of 11-hydroxyeudesmanolides.  

PubMed

Biotransformations of 4alpha- and 4beta-hydroxyeudesmane derivatives by the filamentous fungus Gliocladium roseum were achieved. Hydroxylation at C-11 was the main action of this microorganism, producing new cryptomeridiol (12 and 14) and 4-epi-cryptomeridiol derivatives (6 and 7), respectively, in good yields. The biotransformation activity of G. roseum toward 4beta-hydroxyeudesmane was focused on the isopropyl moiety, but more scattered on the 4alpha-hydroxylated derivative, acting in both the "A" and "B" rings and the isopropyl group of the molecule. Semisyntheses of 11-hydroxyeudesmanolides from the isolated 11,12-dihydroxylated metabolites were also accomplished and used in assigning the stereochemistry of hydroxylation. PMID:12141862

García-Granados, Andrés; Gutiérrez, María C; Parra, Andrés; Rivas, Francisco

2002-07-01

82

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 ...

83

Isolation and Chemical Characterization of a Zinc Dialkyldithiophosphate-Derived Antiwear Agent  

Microsoft Academic Search

A secondary-alkyl zinc dialkyldithiophosphate (ZDP) was thermally decomposed in the presence of air. The resulting precipitate, when blended in a base grease, demonstrated better antiwear performance in a 4-ball wear machine than the parent additive. When extracted with acetone, a white powder with excellent antiwear properties was obtained from the precipitate. Chemical analysis indicated that this white powder was approximately

Albert Molina

1986-01-01

84

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

Microsoft Academic Search

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

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

1980-01-01

85

Comparison of earthworm and fish-derived chemicals eliciting prey attack by garter snakes ( Thamnophis )  

Microsoft Academic Search

Materials eliciting increased tongue flicking and prey attack in garter snakes were isolated from both earthworm and fish prey. New extraction methods based on chloroform-methanol mixtures are valuable adjuncts to the more typical aqueous preparations. Both high- and low-molecular weight components from earthworms and fish were active. The similarity between the active chemicals in these two classes of prey was

Gordon M. Burghardt; Scot E. Goss; Fred M. Schell

1988-01-01

86

Attenuation of 1-(m-chlorophenyl)-biguanide induced hippocampus-dependent memory impairment by a standardised extract of Bacopa monniera (BESEB CDRI-08).  

PubMed

Bacopa monniera is a well-known medhya-rasayana (memory enhancing and rejuvenating) plant in Indian traditional medical system of Ayurveda. The effect of a standardized extract of Bacopa monniera (BESEB CDRI-08) on serotonergic receptors and its influence on other neurotransmitters during hippocampal-dependent learning was evaluated in the present study. Wistar rat pups received a single dose of BESEB CDRI-08 during postnatal days 15-29 showed higher latency during hippocampal-dependent learning accompanied with enhanced 5HT(3A) receptor expression, serotonin and acetylcholine levels in hippocampus. Furthermore, 5HT(3A) receptor agonist 1-(m-chlorophenyl)-biguanide (mCPBG) impaired learning in the passive avoidance task followed by reduction of 5HT(3A) receptor expression, 5HT and ACh levels. Administration of BESEB CDRI-08 along with mCPBG attenuated mCPBG induced behavioral, molecular and neurochemical alterations. Our results suggest that BESEB CDRI-08 possibly acts on serotonergic system, which in turn influences the cholinergic system through 5-HT(3) receptor to improve the hippocampal-dependent task. PMID:21735137

Rajan, Koilmani Emmanuvel; Singh, Hemant K; Parkavi, Arunagiri; Charles, Prisila Dulcy

2011-07-07

87

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

Microsoft Academic Search

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

G Bereket; E Hür; C Ö?retir

2002-01-01

88

Using tandem mass spectrometry to predict chemical transformations of 2-pyrimidinyloxy- N -arylbenzyl amine derivatives in solution  

Microsoft Academic Search

Tandem mass spectrometry is used to predict the chemical transformations of 2-pyrimidinyloxy-N-arylbenzyl amine derivatives. Compound 1, N-2-2-4,6- dimethoxypyrimidin-2-yloxy benzylamino phenyl benzamide was selected as a model to present our idea. The CID reactions\\u000a of protonated 1 include an intramolecular S\\u000a N\\u000a 2 reaction and a cyclodehydration reaction. Under in-source CID conditions, deprotonated 1 undergoes a Smiles rearrangement reaction and then

Hao-Yang Wang; Xiang Zhang; Yin-Long Guo; Qing-Hong Tang; Long Lu

2006-01-01

89

Chemically-modified polysaccharide extract derived from Leucaena leucocephala alters Raw 264.7 murine macrophage functions.  

PubMed

In this study, a chemical modification of the polysaccharides extract (E) derived from Leucaena leucocephala seeds was performed to prepare C-glycosidic 2-propanol derivative (PE), and its sulphated derivative (SPE). This study aimed to characterize immunomodulatory activities of the original extract and its derivatives by exploring their effects on Raw macrophage 264.7 functions and their antioxidant activity. Our results indicated that PE was an effective radical scavenger to hydroxyl, peroxyl, and superoxide anion radicals, and SPE was a peroxyl radical scavenger. PE and SPE were found to influence the macrophage functions. Both of PE and SPE enhanced the macrophage proliferation and phagocytosis of FITC-zymosan; PE inhibited nitric oxide (NO) generation and tumor necrosis factor-alpha (TNF-alpha) secretion in lipopolysaccharide (LPS)-stimulated Raw macrophage 264.7. In contrast, SPE over-induced NO generation and TNF-alpha secretion. Moreover, PE strongly inhibited the binding affinity of FITC-LPS to Raw 264.7, as indicated by flow cytometry analysis. These findings revealed that PE may act as a potent anti-inflammatory agent; however SPE may act as an inducer of macrophage functions against pathogens. PMID:17466921

Gamal-Eldeen, Amira M; Amer, Hassan; Helmy, Wafaa A; Talaat, Roba M; Ragab, Halla

2007-03-05

90

Chemical synthesis, characterisation and biological evaluation of lactonic-estradiol derivatives as inhibitors of 17?-hydroxysteroid dehydrogenase type 1.  

PubMed

To control estradiol (E2) formation, we are interested in synthesizing inhibitors of 17?-hydroxyteroid dehydrogenase type 1 (17?-HSD1). Since the results of docking experiments have shown that E2-lactone derivatives substituted in position 19 or 20 (E-ring) could generate interactions with the active site of the enzyme, we carried out their chemical synthesis. After having prepared the 16?,17?-?-lactone-E2 in four steps starting from estrone (E1), we introduced the molecular diversity by adding a hydroxymethyl, a methylcarboxylate, a carboxy or an allyl group. The allyl derivative was used as a key intermediate to generate a hydroxyethyl side chain in ? or ? position. Two lactols were also obtained from two hydroxyalkyl lactones. Enzymatic assays revealed that lactone and lactol derivatives weakly inhibited 17?-HSD1 in homogenized HEK-293 cells overexpressing 17?-HSD1 (34-60% at 1?M) and in intact T-47D cells expressing 17?-HSD1 (10-40% at 10?M). This article is part of a Special Issue entitled "Synthesis and biological testing of steroid derivatives as inhibitors". PMID:23685015

Farhane, Siham; Fournier, Michelle-Audrey; Poirier, Donald

2013-05-15

91

Native chemical ligation derived method for recombinant peptide/protein C-terminal amidation.  

PubMed

C-terminal amidation is often a requisite structural feature for peptide hormone bio-activity. We report a chemical amidation method that converts peptide/protein thioesters into their corresponding C-terminal amides. The peptide/protein thioester is treated with 1-(2,4-dimethoxyphenyl)-2-mercaptoethyl auxiliary (1b) in a native chemical ligation (NCL) reaction to form an intermediate, which upon removal of the auxiliary with TFA, yields the peptide/protein amide. We have demonstrated the general utility of the approach by successfully converting several synthetic peptide thioesters to peptide amides with high conversion rates. Preliminary results of converting a recombinant peptide thioester to its amide form are also reported. PMID:23880540

Sun, Chengzao; Luo, Gary; Neravetla, Swetha; Ghosh, Soumitra S; Forood, Bruce

2013-07-06

92

Chromatographic Separation of Isomers of Tribenzylgermanium Nitrile Derivatives using Chemically Bonded Aryl Stationary Phases  

Microsoft Academic Search

The present work concerns the development and optimisation of an HPLC method with UV detection in order to separate new organogermanium compounds (3?tribenzylgermanyl?butyronitrile and 4?tribenzylgermanyl?butyronitrile). Organic germanium compounds have found application as pharmaceutical drugs, as biostimulators in agriculture, and in the electronic industry. Three types of stationary phase: octyl, octadecyl, and aryl chemically bonded phases have been investigated. The octadecyl

Krzysztof Pypowski; Iwona Uszy?ska; Mariusz Kluska

2006-01-01

93

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

SciTech Connect

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.

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

1981-01-01

94

Oxygen carrier development for chemical looping combustion of coal derived synthesis gas  

Microsoft Academic Search

In the present work, NETL researchers have studied chemical looping combustion (CLC) with an oxygen carrier NiO\\/bentonite (60 wt.% NiO) for the IGCC systems utilizing simulated synthesis gas. Multi cycle CLC was conducted with NiO\\/Bentonite in TGA at atmospheric pressure and in a high pressure reactor in a temperature range between 700-900°C. Global reaction rates of reduction and oxidation as

R. V. Siriwardane; K. Chaudhari; A. N. Zinn; T. Simonyi; Clark Robinson; J. A. Poston

2006-01-01

95

Chemical-looping combustion of coal-derived synthesis gas over copper oxide oxygen carriers  

Microsoft Academic Search

CuO\\/bentonite and CuO-BHA nanocomposites were studied as oxygen carriers in chemical-looping;\\u000acombustion (CLC) of simulated synthesis gas. Global reaction rates of reduction and oxidation, as the function;\\u000aof reaction conversion, were calculated from 10-cycle oxidation\\/reduction tests utilizing thermogravimetric;\\u000aanalysis at atmospheric pressure between 700 and 900 °C. It was found that the reduction reactions are always;\\u000afaster than oxidation reactions;

Hanjing Tian; Karuna Chaudhari; Thomas Simonyi; James Poston; Tengfei Liu; Tom Sanders; Go?tz Veser; Ranjani Siriwardane

2008-01-01

96

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

PubMed

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

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

2007-01-09

97

NMR chemical shift reagents in structural determination of lipid derivatives: II. Methyl petroselinate and methyl oleate  

Microsoft Academic Search

Whentris(1,1,1,2,2,3,3-heptafluoro-7,7-dimethyl-4,6-octaneodionato)europium (III)—Eu(fod)3—forms a complex with a sufficiently basic functional group in a donor molecule, the change in the magnetic environment of\\u000a protons near the coordination site causes their nuclear magnetic resonance (NMR) signals to shift to different positions.\\u000a Consequently Eu(fod)3 and other compounds that similarly affect NMR signals have been designated chemical shift reagents (csr). Because of their\\u000a ability to

John P. Wineburg; Daniel Swern

1972-01-01

98

Chemical constituents of marine algal-derived endophytic fungus Exophiala oligosperma EN-21  

NASA Astrophysics Data System (ADS)

Seven compounds (1-7) were identified from the cultivation of the endophytic fungus Exophiala oligosperma (EN-21) that was isolated from the inner tissue of the marine red alga Laurencia similis. Their structures were identified with spectroscopic and chemical methods as 2-phenoxynaphthalene ( 1), (2 S, 3 R, 4 E, 8 E)-1- O-?-D-glucopyranosyl-3-hydroxy-2-[( R)-2'-hydroxyoctadecanoyl] amino-9-methyl-4, 8-octadeca-diene ( 2), (22 E,24 R)-ergosta-7,22-dien-3?,5?,6?-triol ( 3), (22 E, 24 R)-3?, 5?, 9?-trihydroxy-ergosta-7, 22-dien-6-one ( 4), (22 E, 24 R)-5?, 6?-epoxy-ergosta-8, 22-dien-3?, 7?-diol ( 5), (22 E, 24 R)-ergosta-4, 6, 8(14), 22-tetraen-3-one ( 6), and euphorbol ( 7). This paper reports for the first time the chemical constituents of fungus Exophiala oligosperma and the discovery of compound 1 as a natural product from the fungus.

Li, Fang; Li, Ke; Li, Xiaoming; Wang, Bingui

2011-01-01

99

Physico-chemical studies of fused phenanthrimidazole derivative as sensitive NLO material  

NASA Astrophysics Data System (ADS)

Heterocyclic phenanthrimidazole derivative, 2-(4-fluorophenyl)-1-p-tolyl-1H-imidazo[4,5-f] [1,10] phenanthroline (FPTIP) has been synthesized and characterised by NMR, mass and CHN analysis. The FPTIP was evaluated concerning their solvatochromic properties and molecular optical nonlinearities. Their electric dipole moment (?), polarizability (?) and hyperpolarizability (?) have been calculated theoretically and the results indicate that the extension of the ?-framework of the ligands has an effect on the NLO properties. The energies of the HOMO and LUMO levels and the molecular electrostatic potential (MEP) energy surface studies have exploited the existence of intramolecular charge transfer (ICT) within the molecule.

Jayabharathi, Jayaraman; Thanikachalam, Venugopal; Sathishkumar, Ramalingam; Jayamoorthy, Karunamoorthy

2013-01-01

100

Physico-chemical studies of fused phenanthrimidazole derivative as sensitive NLO material.  

PubMed

Heterocyclic phenanthrimidazole derivative, 2-(4-fluorophenyl)-1-p-tolyl-1H-imidazo[4,5-f] [1,10] phenanthroline (FPTIP) has been synthesized and characterised by NMR, mass and CHN analysis. The FPTIP was evaluated concerning their solvatochromic properties and molecular optical nonlinearities. Their electric dipole moment (?), polarizability (?) and hyperpolarizability (?) have been calculated theoretically and the results indicate that the extension of the ?-framework of the ligands has an effect on the NLO properties. The energies of the HOMO and LUMO levels and the molecular electrostatic potential (MEP) energy surface studies have exploited the existence of intramolecular charge transfer (ICT) within the molecule. PMID:23103466

Jayabharathi, Jayaraman; Thanikachalam, Venugopal; Sathishkumar, Ramalingam; Jayamoorthy, Karunamoorthy

2012-10-05

101

Indole-3-piperazinyl derivatives: novel chemical class of 5-HT(6) receptor antagonists.  

PubMed

N(1)-Arylsulfonyl-3-piperazinyl indole derivatives were designed and identified as a novel class of 5-HT(6) receptors ligands. All the compounds have high affinity and antagonist activity towards 5-HT(6) receptor. The compound 7a (K(i) = 3.4 nM, functional assay IC(50) = 310 nM) shows enhanced cognitive effect when tested in NORT and Morris water maze models. Synthesis, SAR and PK profile of these novel compounds constitute the subject matter of this Letter. PMID:21134749

Nirogi, Ramakrishna V S; Deshpande, Amol D; Kambhampati, Ramasastri; Badange, Rajesh Kumar; Kota, Laxman; Daulatabad, Anand V; Shinde, Anil K; Ahmad, Ishtiyaque; Kandikere, Vishwottam; Jayarajan, Pradeep; Dubey, P K

2010-11-05

102

Murine bone marrow-derived dendritic cells as a potential in vitro model for predictive identification of chemical sensitizers.  

PubMed

The identification of potential sensitizing chemicals is a key step in the safety assessment process. To this end, predictive tests that require no or few animals and that are reliable, inexpensive and easy to perform are needed. The aim of this study was to evaluate the performance of murine bone marrow-derived dendritic cells (BMDCs) in an in vitro skin sensitization model. BMDCs were exposed to six well-known allergens (dinitrochlorobenzene, DNCB; dinitrofluorobenzene, DNFB; Bandrowski's base, BB; paraphenylenediamine, PPD; nickel sulfate, NiSO(4); cinnamaldehyde, Cinn). Surface expression of MHC class II, CD40, CD54, and CD86 was measured by flow cytometry after 48h exposure to these chemicals. All the allergens tested induced a significant increase in marker expression, with an augmentation in the percentage of mature cells ranging from 2.3- to 10.5-fold change over control. The level of up-regulation was dependent on the concentration and the strength of the allergens. In contrast, the irritants (sodium dodecyl sulfate, SDS and 4-aminobenzoic acid, pABA) and the negative control (zinc sulfate, ZnSO(4)) tested induced either no modification or a down-regulation of membrane marker expression. Taken together, our data suggest that murine BMDCs may represent a new and valuable in vitro model to predict the sensitizing properties of chemicals. PMID:18006254

Pépin, Elsa; Goutet, Michèle; Ban, Masarin

2007-10-02

103

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

PubMed

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

Van den Heuvel, Willem; Soncini, Alessandro

2013-02-01

104

NMR chemical shift as analytical derivative of the Helmholtz free energy  

NASA Astrophysics Data System (ADS)

We present a theory for the temperature-dependent nuclear magnetic shielding tensor of molecules with arbitrary electronic structure. The theory is a generalization of Ramsey's theory for closed-shell molecules. The shielding tensor is defined as a second derivative of the Helmholtz free energy of the electron system in equilibrium with the applied magnetic field and the nuclear magnetic moments. This derivative is analytically evaluated and expressed as a sum over states formula. Special consideration is given to a system with an isolated degenerate ground state for which the size of the degeneracy and the composition of the wave functions are arbitrary. In this case, the paramagnetic part of the shielding tensor is expressed in terms of the g and A tensors of the electron paramagnetic resonance spin Hamiltonian of the degenerate state. As an illustration of the proposed theory, we provide an explicit formula for the paramagnetic shift of the central lanthanide ion in endofullerenes Ln@C60, with Ln = Ce3+, Nd3+, Sm3+, Dy3+, Er3+, and Yb3+, where the ground state can be a strongly spin-orbit coupled icosahedral sextet for which the paramagnetic shift cannot be described by previous theories.

Van den Heuvel, Willem; Soncini, Alessandro

2013-02-01

105

A forward chemical screen using zebrafish embryos with novel 2-substituted 2H-chromene derivatives.  

PubMed

We synthesized 2-substituted 2H-chromene derivatives from salicylaldehyde using potassium vinylic borates in the presence of secondary amines. Our goal was to generate novel compounds that might modulate transforming growth factor-beta signaling, based on limited rational design. Potassium vinyl trifluoroborates react with salicylaldehydes at 80 degrees C in the presence of a secondary amine and produce 2-substituted 2H-chromene derivatives with a 70-90% yield. A small library of these compounds, predicted to potentially interact with transforming growth factor-beta receptors, was screened for bioactivity in living zebrafish embryos. We found that the related compounds differentially affect development, and demonstrate one compound that produces severe body axis alterations in early embryogenesis and at lower doses affects specifically cardiovascular development. This compound modulates specifically a Smad-independent transforming growth factor-beta-regulated mitogen-activated protein kinase pathway, namely p-SAPK/JNK. These compounds, as suggested by our biological assays, may prove useful to manipulate developmental programs and develop therapeutic tools. PMID:19207470

Torregroza, Ingrid; Evans, Todd; Das, Bhaskar C

2009-03-01

106

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

PubMed

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

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

2012-09-16

107

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

NASA Astrophysics Data System (ADS)

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.

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

108

Chemical ozone losses in Arctic and Antarctic polar winter/spring season derived from SCIAMACHY limb measurements 2002-2009  

NASA Astrophysics Data System (ADS)

Stratospheric ozone profiles are retrieved for the period 2002-2009 from SCIAMACHY measurements of limb-scattered solar radiation in the Hartley and Chappuis absorption bands of ozone. This data set is used to determine the chemical ozone losses in both the Arctic and Antarctic polar vortices by averaging the ozone in the vortex at a given potential temperature. The chemical ozone losses at isentropic levels between 450 K and 600 K are derived from the difference between observed ozone abundances and the ozone modelled taking diabatic cooling into account, but no chemical ozone loss. Chemical ozone losses of up to 30-40% between mid-January and the end of March inside the Arctic polar vortex are reported. Strong inter-annual variability of the Arctic ozone loss is observed, with the cold winters 2004/2005 and 2006/2007 showing chemical ozone losses inside the polar vortex at 475 K, where 1.7 ppmv and 1.4 ppmv of ozone were removed, respectively, over the period from 22 January to beginning of April and 0.9 ppmv and 1.2 ppmv, respectively, during February. For the winters of 2007/2008 and 2002/2003, ozone losses of about 0.8 ppmv and 0.4 ppmv, respectively are estimated at the 475 K isentropic level for the period from 22 January to beginning of April. Essentially no ozone losses were diagnosed for the relatively warm winters of 2003/2004 and 2005/2006. The maximum ozone loss in the SCIAMACHY data set was found in 2007 at the 600 K level and amounted to about 2.1 ppmv for the period between 22 January and the end of April. Enhanced losses close to this altitude were found in all investigated Arctic springs, in contrast to Antarctic spring. The inter-annual variability of ozone losses and PSC occurrence rates observed during Arctic spring is consistent with the known QBO effects on the Arctic polar vortex, with exception of the unusual Arctic winter 2008/2009. The maximum total ozone mass loss of about 25 million tons was found in the cold Arctic winter of 2004/2005 inside the polar vortex between the 450 K and 600 K isentropic levels from mid-January until the middle of March. The Antarctic vortex averaged ozone loss as well as the size of the polar vortex do not vary much from year to year. The total ozone mass loss inside the Antarctic polar vortex between the 450 K and 600 K isentropic levels is about 50-60 million tons and the vortex volume for this altitude range varies between about 150 and 300 km3 for the period between mid-August and mid-November of every year studied, except for 2002. In 2002 a mid-winter major stratospheric warming occurred in the second half of September and the ozone mass loss was only about half of the value in the other years. However, inside the polar vortex we find chemical ozone losses at the 475 K isentropic level that are similar to those in all other years studied. At this isentropic level ozone losses of 70-90% between mid-August and mid-November or about 2.5 ppmv are observed every year. At isentropic levels above 500 K the chemical ozone losses were found to be larger in 2002 than in all other years studied. Comparisons of the vertical variation of ozone losses derived from SCIAMACHY observations with several independent techniques for the Arctic winter 2004/2005 show that the SCIAMACHY results fall in the middle of the range of previously published results for this winter. For other winters in both hemispheres - for which comparisons with other studies were possible - the SCIAMACHY results are consistent with the range of previously published results.

Sonkaew, T.; von Savigny, C.; Eichmann, K.-U.; Weber, M.; Rozanov, A.; Bovensmann, H.; Burrows, J. P.; Grooß, J.-U.

2013-02-01

109

Synthesis and evaluation of resveratrol derivatives as new chemical entities for cancer.  

PubMed

Resveratrol has been shown to be active in inhibiting multistage carcinogenesis. The potential use of resveratrol in cancer chemoprevention or chemotherapy settings has been hindered by its short half-life and low bioavailability. Considering the above remarks, using resveratrol as a prototype, we have synthesized two derivatives of resveratrol. Their activity was evaluated using in vitro and in silico analysis. Biological evaluation of resveratrol analogues on U937 cells had shown that two synthesized analogues of resveratrol had higher rates of inhibition than the parental molecule at 10?M concentration. EMSA conducted for NF-kB revealed that these molecules significantly interfered in the DNA binding ability of NF-kB. It was found that these molecules suppressed the expression of TNF?, TNFR, IL-8, actin and activated the expression of FasL, FasR genes. To understand possible molecular mechanism of the action we performed docking and dynamic studies, using NF-kB as a receptor. Results showed that resveratrol, RA1 and RA2 interacted with the residues involved in DNA binding. Resveratrol analogues by interacting NF-kB might have prevented its translocation and also by interacting with the residues involved in DNA binding might have prevented the binding of NF-kB to DNA. This may be the reason for suppression of NF-kB binding to DNA. PMID:23500626

Mulakayala, Chaitanya; Babajan, B; Madhusudana, P; Anuradha, C M; Rao, Raja Mohan; Nune, Ravi Prakash; Manna, Sunil Kumar; Mulakayala, Naveen; Kumar, Chitta Suresh

2013-02-04

110

Highly uniform 300 mm wafer-scale deposition of single and multilayered chemically derived graphene thin films.  

PubMed

The deposition of atomically thin highly uniform chemically derived graphene (CDG) films on 300 mm SiO(2)/Si wafers is reported. We demonstrate that the very thin films can be lifted off to form uniform membranes that can be free-standing or transferred onto any substrate. Detailed maps of thickness using Raman spectroscopy and atomic force microscopy height profiles reveal that the film thickness is very uniform and highly controllable, ranging from 1-2 layers up to 30 layers. After reduction using a variety of methods, the CDG films are transparent and electrically active with FET devices yielding high mobilities of approximately 15 cm(2)/(V s) and sheet resistance of approximately 1 kOmega/sq at approximately 70% transparency. PMID:20050640

Yamaguchi, Hisato; Eda, Goki; Mattevi, Cecilia; Kim, Hokwon; Chhowalla, Manish

2010-01-26

111

Chemical Evolution of Amphiphiles: Glycerol Monoacyl Derivatives Stabilize Plausible Prebiotic Membranes  

NASA Astrophysics Data System (ADS)

The self-assembly of simple amphiphiles like fatty acids into cell-like membranous structures suggests that such structures were available on prebiotic Earth to support the origin of cellular life. However, the composition of primitive membranes remains unclear because the physical properties of the aqueous environment in which they assembled are relatively unconstrained in terms of temperature, pH, and ionic concentrations. It seems likely that early membranes were composed of mixtures of various amphiphiles in an aqueous medium warmed by geothermal activity prevalent in the Archean era. To better understand the properties of mixed bilayers formed by binary mixtures of single-chain amphiphiles under these conditions, we conducted stability experiments, using membranes composed of various fatty acids having hydrocarbon chain length between 8 and 18 carbons, in mixtures with their glycerol monoacyl amphiphile derivatives (GMAs). The parameters investigated were critical vesicle concentration (CVC), encapsulation, and temperature-dependent stability. We found that hydrocarbon chain length and the presence of GMAs were major factors related to membrane stability. As chain length increased, GMA additions decreased the CVC of the mixtures 4- to 9-fold. Encapsulation ability also increased significantly as a function of chain length, which reduced permeation of small marker molecules. However, long exposures to temperatures in excess of 60°C resulted in a total release of encapsulated solutes and extensive mixing of the membrane components between vesicles. We conclude that GMAs can significantly increase the stability of mixed amphiphile membranes, but further studies are required to establish model membranes that are stable at elevated temperatures.

Maurer, S. E.; Deamer, D. W.; Boncella, J. M.; Monnard, P.-A.

2009-12-01

112

Analysis of estrogens in river water and effluents using solid-phase extraction and gas chromatography–negative chemical ionisation mass spectrometry of the pentafluorobenzoyl derivatives  

Microsoft Academic Search

A procedure was developed for the analysis of estrogens in environmental water and effluents. Samples were extracted by passing through polymer-impregnated solid-phase extraction discs or C18 cartridges, followed by gas chromatography–negative chemical ionisation mass spectrometry of the pentafluorobenzoyl derivatives. The derivatives were stable and gave diagnostic negative molecular ions as the base peak for each of the major estrogens studied.

Xiao-Yao Xiao; David V McCalley; James McEvoy

2001-01-01

113

Seasonal cycles in radium and barium within a subterranean estuary: Implications for groundwater derived chemical fluxes to surface waters  

NASA Astrophysics Data System (ADS)

There is increasing evidence that submarine groundwater discharge (SGD) is an important source of water and dissolved materials to the ocean. One of the primary tracers of this process is the quartet of radium isotopes (223Ra, 224Ra, 226Ra and 228Ra), whereby excess activities in surface waters can often be attributed to an input supplied via SGD. This approach requires the radium end member activity to be well constrained, however, natural variability in groundwater radium may span several orders of magnitude. Therefore, this variability is usually the main driver of uncertainties in volumetric SGD estimates. To investigate the physical and biogeochemical controls on groundwater radium activities, we conducted a three-year time series of radium and barium, a chemical analogue for radium, within the subterranean estuary of a coastal aquifer (Waquoit Bay, MA, USA). Gonneea et al. (2013) demonstrated that movement of the salinity interface within the subterranean estuary is driven by changes in the hydraulic gradient between groundwater level and sea level height. For Waquoit Bay, seasonal scale sea level change, not groundwater level, was the main driver in hydraulic gradient fluctuations. Seasonal changes in groundwater chemistry can be attributed to the resulting movement of the salinity transition zone between terrestrial and marine groundwater. Landward movement of the interface results in a large release of radium isotopes (226Ra = 1400 dpm 100 L?1) and barium (3000 nmol kg?1) associated with an increase in groundwater salinity. The magnitude of these releases cannot be explained by in situ production or weathering alone, but is likely due to salinity driven desorption from surface-bound sediment inventory. The timing of these peak concentrations is not always in phase with model-derived estimates of SGD; as a result, the groundwater concentration rather than the water flux is the main driver of Ra and Ba inputs to Waquoit Bay surface waters. The behavior of the subterranean estuary as an ion exchange reservoir has important implications for the timing and flux of various nutrients and pollutants that transit this region prior to discharge. In addition to modulating chemical fluxes via submarine groundwater discharge on seasonal time scales, transgression of the subterranean estuary may alter the input of chemicals to the ocean on decadal and longer time scales. During this study, the observed excess flux of 226Ra and Ba from the subterranean estuary can be accounted for with sorbed sediment pools and accelerating rates of sea level rise in this region.

Gonneea, Meagan Eagle; Mulligan, Ann E.; Charette, Matthew A.

2013-10-01

114

Effects of mechanical and chemical stimuli on ?differentiation of human adipose-derived stem ?cells into endothelial cells.  

PubMed

It has been hypothesized that application of the micromechanical environment that target cells experience in vivo enhances functionality of differentiated cells. Vascular endothelial cells, functioning at the interface of the blood-vessel wall, are vital to the performance of the cardiovascular system. They are subject to shear and tensile stresses induced by blood flow and pressure, respectively.?This study investigated effects of shear/tensile stresses on endothelial differentiation of adipose-?derived mesenchymal stem cells (ASCs) utilizing a custom-made bioreactor capable of applying both shear and tensile stresses. The loading values of 10% cyclic stretch, 0-2.5 dyn/cm2 cyclic shear stress, and combined loadings were used. To examine the extent of mechanical and chemical stimuli in ?acquisition of endothelial characteristics by ASCs, the expression of three major endothelial genes were quantified when ASCs were treated by three loading regimes and endothelial growth factor for three different durations (1, 2, and 7 days). In general, cyclic stretch decreased expression of FLK-1 ?and vWF, while cyclic shear elevated expression levels. The combined loading regime had minor ?effects on the expression of the two markers. All types of loadings significantly enhanced the expression level of VE-cadherin with the most prominent increase by combined loading. It was concluded that applying different loading regimes assists in adjusting the expression level of endothelial markers to achieve functional endothelial cells for cardiovascular engineering. PMID:23918273

Shojaei, Shahrokh; Tafazzoli-Shahdpour, Mohamad; Shokrgozar, Mohamad Ali; Haghighipour, Nooshin

2013-08-02

115

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

PubMed

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

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

2012-06-13

116

Chemical induction of subcutaneous tumors in balb\\/c and swiss mice infected with wild type c rna viruses derived from balb\\/c tissues  

Microsoft Academic Search

SUMMARY The effect of exogenous type C RNA viruses derived from BALB\\/c mice on the chemical induction of s .c. tumors in mice was determined in relation to host strain, age at treatment, sex, carcinogen dose, and virus strain . Viruses that were cocarcinogenic in Swiss mice were anticarcinogenic or without effect in BALB\\/c mice under similar treatment conditions .

Ronald A. Salerno; G M Ramm; C E Whitmire

1973-01-01

117

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

Technology Transfer Automated Retrieval System (TEKTRAN)

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

118

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)

Xanthene and its derivatives have been found to be effective inhibitors for the corrosion of mild steel in acidic medium. Quantum chemical parameters were calculated using DFT. The multiple-linear regression analyses fitted the theoretical data well. The results obtained in this study indicated that protonated species represent better the actual experimental situation.

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

2011-09-01

119

Optimisation of chemical purification conditions for direct application of solid metal salt coagulants: treatment of peatland-derived diffuse runoff.  

PubMed

The drainage of peatland areas for peat extraction, agriculture or bioenergy requires affordable, simple and reliable treatment methods that can purify waters rich in particulates and dissolved organic carbon. This work focused on the optimisation of chemical purification process for the direct dosage of solid metal salt coagulants. It investigated process requirements of solid coagulants and the influence of water quality, temperature and process parameters on their performance. This is the first attempt to provide information on specific process requirements of solid coagulants. Three solid inorganic coagulants were evaluated: aluminium sulphate, ferric sulphate and ferric aluminium sulphate. Pre-dissolved aluminium and ferric sulphate were also tested with the objective of identifying the effects of in-line coagulant dissolution on purification performance. It was determined that the pre-dissolution of the coagulants had a significant effect on coagulant performance and process requirements. Highest purification levels achieved by solid coagulants, even at 30% higher dosages, were generally lower (5%-30%) than those achieved by pre-dissolved coagulants. Furthermore, the mixing requirements of coagulants pre-dissolved prior to addition differed substantially from those of solid coagulants. The pH of the water samples being purified had a major influence on coagulant dosage and purification efficiency. Ferric sulphate (70 mg/L) was found to be the best performing solid coagulant achieving the following load removals: suspended solids (59%-88%), total organic carbon (56%-62%), total phosphorus (87%-90%), phosphate phosphorus (85%-92%) and total nitrogen (33%-44%). The results show that the use of solid coagulants is a viable option for the treatment of peatland-derived runoff water if solid coagulant-specific process requirements, such as mixing and settling time, are considered. PMID:23923774

Heiderscheidt, Elisangela; Saukkoriipi, Jaakko; Ronkanen, Anna-Kaisa; Kløve, Bjørn

2013-04-01

120

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

SciTech Connect

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

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

1990-09-01

121

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

Microsoft Academic Search

The measurement of total-body electrical conductivity (TOBEC) has become one of the standard methods for the estimation of body composition in infants. The authors investigated, using nonhuman 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

N. C. DeBruin; I. H. T. Luijendijk; H. K. A. Visser; H. J. Degenhart

1994-01-01

122

Effect of multi-coating process on the orientation and microstructure of lead zirconate titanate (PZT) thin films derived by chemical solution deposition  

Microsoft Academic Search

This paper describes the effects of multi-coating processes on the orientation, microstructure and electrical property of lead zirconate titanate (PZT) thick films derived by chemical solution deposition. PZT thick films (>1 ?m in thickness) were deposited by various multi-coating processes, such as layer-by-layer crystallization, seed-layering or single-crystallization. The orientation and microstructure of the thick films were characterized by X-ray diffractometry

T. Kobayashi; M. Ichiki; J. Tsaur; R. Maeda

2005-01-01

123

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

Microsoft Academic Search

The effect of hydrogen sulfide (HS) 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 HS, metal-oxide oxygen carriers were first reduced by carbon

Hanjing Tian; Thomas Simonyi; James Poston; Ranjani Siriwardane

2009-01-01

124

Synthechol™ Ynthetic Cholesterol for Cholesterol Dependent Cell Culture — Development of Non-Animal Derived Chemically Defined NS0 Medium  

Microsoft Academic Search

Traditional serum supplemented cell culture medium is fast becoming outdated as new technology permits the omission of most animal derived protein from the culture system. Cell lines derived from the NS0 myeloma cell line are rising in popularity for biopharmaceutical production, due to their high cell growth potential and their subsequent high production yields. However, because of their cholesterol auxotrophic

D. Talley; B. Cutak; E. Rathbone; T.-Kolla; D. Allison; J. Blasberg; K. Kao; M. Caple

125

Chemical Profiles and Identification of Key Compound Caffeine in Marine-Derived Traditional Chinese Medicine Ostreae concha  

PubMed Central

To compare the chemical differences between the medicinal and cultured oyster shells, their chemical profiles were investigated. Using the ultra performance liquid chromatography-electron spraying ionization-mass spectrometry (UPLC-ESI-MS), combined with principal component analysis (PCA) and orthogonal projection to latent structures discriminant analysis (OPLS-DA), the discrimination of the chemical characteristics among the medicinal and cultured oyster shells was established. Moreover, the chemometric analysis revealed some potential key compounds. After a large-scale extraction and isolation, one target key compound was unambiguously identified as caffeine (1) based on extensive spectroscopic data analysis (1D and 2D NMR, MS, and UV) and comparison with literature data.

Yang, Xue; Zhou, Shi-Lu; Ma, Ai-Cui; Xu, Hai-Tao; Guan, Hua-Shi; Liu, Hong-Bing

2012-01-01

126

Physical and Chemical Characterization and Comparison of Solids, Liquids, and Oils Derived from Estonian and Green River Formation Shales.  

National Technical Information Service (NTIS)

Although only a single Estonian raw shale sample with an unknown history has been examined, physical and chemical characterization of this material has been accomplished. A comparison with a representative Green River formation raw shale has been made. So...

E. J. Peterson W. D. Spall

1981-01-01

127

Chemical Shifts and Coupling Constants in Pentafluorophenyl Derivatives. Ii. Application to a Study of Bonding in Selected Compounds.  

National Technical Information Service (NTIS)

The pi interactions within molecules containing the pentafluorophenyl group are examined using the coupling constant-chemical shift relationship as proposed in the preceding paper. The following series, selected from the 73 pentafluorophenyl compounds stu...

M. G. Hogben R. S. Gay A. J. Oliver J. A. J. Thompson W. A. G. Graham

1968-01-01

128

Prodrugs of peptides. 11. Chemical and enzymatic hydrolysis kinetics of N-acyloxymethyl derivatives of a peptide-like bond.  

PubMed

Various carboxylic acid esters of the N-hydroxymethyl derivative of N-benzyloxycarbonylglycine benzylamide, used as a peptide-like model, were prepared and their decomposition kinetics studied in aqueous solution and in human plasma solutions. These N-acyloxymethylamide derivatives were found to undergo a facile decomposition by a pH-independent process in the pH range 4-8.5, the half-lives being 1-11hr at 37 degrees C. The cause of this limited stability was suggested to be due to the occurrence of an elimination-addition mechanism involving a reactive N-acylminium ion intermediate. In alkaline solutions (pH greater than 10) the derivatives showed a normal ester stability. The ester group in the N-acyloxymethyl derivatives was readily hydrolyzed by plasma enzymes to yield the N-hydroxymethyl amide, which subsequently decomposed to the parent amide. The results obtained suggest that N-acyloxymethylation of a peptide bond may be a useful prodrug approach to obtain derivatives with varying lipophilicities and a ready ability to undergo conversion to the parent peptide in vivo. However, the stability of the derivatives in aqueous solutions is limited. PMID:1796040

Bundgaard, H; Rasmussen, G J

1991-10-01

129

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

PubMed

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

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

2013-05-21

130

Photoluminescence of 1,3-Diphenyl-1H-pyrazolo[3,4-b]quinoline and its derivatives: Experiment and quantum chemical simulations  

NASA Astrophysics Data System (ADS)

The optical absorption and photoluminescent spectra are studied in recently synthesized diphenyl pyrazoloquinolines (DPPQ): 1,3-diphenyl-1H-pyrazolo[3,4-b] quinoline and its 6-vinyl, 6-N,N-diphenyl, 6-methyl, 6-fluoro, 6-bromo and 6-chloro derivatives. The photoemission spectra are recorded in organic solvents of different polarity and found to be highly solvatochromic. The measured spectra are compared with the quantum chemical calculations performed by means of the semiempirical methods (AM1 or PM3) in combination with the equilibrium molecular conformation (EMC) in vacuo (T = 0 K, ? = 0.12 eV) or MD simulations (T = 300 K). The broadening of absorption and emission bands and their red-shift with increasing of temperature may be well reproduced by MD simulations. The Stokes shift of the photoluminescent spectra is obtained by including vibrational modes into the emission equation. The quantum chemical method AM1 in combination with MD simulations gives in most cases the best agreement with the experimental data. By comparing the emission spectra of 6-N,N-diphenyl-DPPQ with other DPPQ-derivatives one concludes that the molecular fragment diphenyl-amin [(C6H5)2N ] is likely subjected to strong conformational changes in solvents. The large difference between the excited- and state-dipole moments indicates on a strong electron transfer effect being common for all DPPQ derivatives.

Ca?us, S.; Gondek, E.; Danel, A.; Jarosz, B.; Kityk, A. V.

2007-03-01

131

Availability of protein-derived amino acids as feedstock for the production of bio-based chemicals  

Microsoft Academic Search

This review describes different potential sources for amino acids that could be used for the production of bulk chemicals in a biorefinery, such as agricultural byproduct streams. Volumes at which these sources and the amino acids therein are available were determined, and the most interesting amino acids in terms of their potential available quantity were identified. The investigated sources are

T. M. Lammens; M. C. R. Franssen; E. L. Scott; J. P. M. Sanders

2012-01-01

132

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

PubMed Central

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.

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

1996-01-01

133

Contaminant and plant-derived changes in soil chemical and microbiological indicators during fuel oil rhizoremediation with Galega orientalis  

Microsoft Academic Search

The aim of this work was to evaluate the effects of vegetation and hydrocarbon (HC) contamination on the development of soil chemical and biological status during rhizoremediation of fuel oil contamination with the legume Galega orientalis. Uncontaminated and unvegetated references monitored in parallel with the rhizoremediation treatment enabled the identification of the partial effects. A 21-week greenhouse experiment simulated one

Anu Mikkonen; Elina Kondo; Kaisa Lappi; Kaisa Wallenius; Kristina Lindström; Helinä Hartikainen; Leena Suominen

2011-01-01

134

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...

135

Corrosion inhibitors part V: QSAR of benzimidazole and 2-substituted derivatives as corrosion inhibitors by using the quantum chemical parameters  

Microsoft Academic Search

Quantum chemical SCF calculations of some parameters of benzimidazoles were correlated with their inhibition efficiency in case of steel in aqueous acidic medium. Geometric structures, total negative charge on the molecule (TNC), highest occupied molecular orbital (EHOMO), lowest unoccupied molecular orbital (ELUMO), dipole moment (?) and linear solvation energy terms, molecular volume (Vi) and dipolar-polarization (?*) were correlated to corrosion

El Sayed H. El Ashry; Ahmed El Nemr; Samy A. Essawy; Safaa Ragab

2008-01-01

136

Impact of zinc substitution on the structural and magnetic properties of chemically derived nanosized manganese zinc mixed ferrites  

Microsoft Academic Search

Mn1-xZnxFe2O4 nanoparticles (x=0-1) were synthesized by wet chemical co-precipitation techniques. X-ray diffraction, transmission electron microscopy and high-resolution transmission electron microscopy were effectively utilized to investigate the different structural parameters. The elemental analysis was conducted using energy-dispersive spectrum and inductively coupled plasma analysis. The magnetic properties such as magnetization and coercivity were measured using vibrating sample magnetometer. The observed magnetization values

E. Veena Gopalan; I. A. Al-Omari; K. A. Malini; P. A. Joy; D. Sakthi Kumar; Yasuhiko Yoshida; M. R. Anantharaman

2009-01-01

137

Catalytic conversion of a biomass-derived oil to fuels and chemicals I: Model compound studies and reaction pathways  

Microsoft Academic Search

The reactions over HZSM-5 catalyst of a number of model compounds were studied in a fixed-bed micro-reactor operating at 3.6 WHSV, atmospheric pressure and temperature range 330–410°C. The compounds were propanoic acid, methyl ester of acetic acid, 4-methylcyclohexanol, cyclopentanone, 2-methylcyclopentanone, methoxybenzene, ethoxybenzene, phenol and 2-methoxy-4-(2-propenyl)phenol. These compounds represented the acid, ester, alcohol, aldehyde and ketone, ether and phenol chemical groups,

J. D. Adjaye; N. N. Bakhshi

1995-01-01

138

Reproducible Growth of Metalorganic Chemical Vapor Deposition Derived YBa2Cu3Ox Thin Films Using Ultrasonic Gas Concentration Analyzer  

NASA Astrophysics Data System (ADS)

We report, in detail, on precursor concentration monitoring in the metalorganic chemical vapor deposition (MOCVD) of YBa2Cu3Ox (YBCO) by ultrasonic measurement and a newly developed feedback system to solve reproducibility problems. The fluctuation of the flow rate of dipivaloylmethanate (DPM) compounds has been clearly observed. We have proposed a feedback system using an ultrasonic concentration analyzer and two sets of mass flow controllers for each precursor, and have proven the validity of the operation.

Yamamoto, Shuu'ichirou; Nagata, Kouji; Sugai, Satoshi; Sengoku, Akio; Matsukawa, Yasunari; Hattori, Takeo; Oda, Shunri

1999-08-01

139

Atomic emission detection for the quantitation of trimethylsilyl derivatives of chemical-warfare-agent related compounds in environmental samples  

Microsoft Academic Search

Quantitation of nerve agent degradation products is needed to develop methods for analysis of environmental samples for verification of the Chemical Weapons Convention. A procedure has been characterized which involves formation of the trimethylsilyl esters of alkylmethylphosphonic acids using 1% trimethylchlorosilane in bis-(trimethylsilyl)trifluoroacetamide as a derivatizing agent. Eight phosphorus-containing acids were extracted from spiked water, wipes, and two soil samples

William R. Creasy; Alex A. Rodríguez; Robert W. Warren

1995-01-01

140

Properties of high ash char particles derived from inertinite-rich coal: 1. Chemical, structural and petrographic characteristics  

Microsoft Academic Search

An investigation was undertaken to determine the properties of high ash coal–chars derived from South African discards rich in inertinites, for the development of suitable overall reaction rate models at low temperatures (<900°C). Detailed characterisation results of the parent coal and chars prepared at 700°C and 900°C obtained from standard coal analytical methods, petrographic techniques, CCSEM image analysis and a

Raymond C. Everson; Hein W. J. P. Neomagus; Rufaro Kaitano; Rosemary Falcon; Chris van Alphen; Vivien M. du Cann

2008-01-01

141

Antimalarial activity of dihydroartemisinin derivatives against P. falciparum resistant to mefloquine: a quantum chemical and multivariate study  

Microsoft Academic Search

Dihydroartemisinin derivatives with antimalarial activity against P. falciparum resistant to mefloquine are proposed with the aid of quantum chemistry and multivariate analysis methods (PCA, KNN, and SIMCA). The principal component analysis (PCA) and hierarchical cluster analysis (HCA) showed that the descriptors: molecular softness (MS), total surface area (TSA), Randic's index, path-1 molecular connectivity-average (CHI1A), bond information index (BIC), shape index

J. C Pinheiro; M. M. C Ferreira; O. A. S Romero

2001-01-01

142

Cycloheptane, cyclooctane and 1,3,5-cycloheptatriene. Low temperature thermal properties, vapor pressure and derived chemical thermodyamic properties  

Microsoft Academic Search

From determinations of the low temperature thermal properties and vapor pressure of cycloheptane, cyclooctane and 1,3,5-cycloheptatriene, values of the entropy in the liquid and vapor states and the heat of vaporization, all at 298.16°K, were obtained. These results and values of the heats of formation derivable from literature data were used to compute values of ..delta..Hf°, ..delta..Ff°, ..delta..Sf° and logââ

H. L. Finke; D. W. Scott; M. E. Gross; J. F. Messerly; G. Waddington

1956-01-01

143

A small chemical library of 2-aminoimidazole derivatives as BACE-1 inhibitors: Structure-based design, synthesis, and biological evaluation.  

PubMed

In this work, we report a rational structure-based approach aimed at the discovery of new 2-aminoimidazoles as ?-secretase inhibitors. Taking advantage of a microwave-assisted synthetic protocol, a small library of derivatives was obtained and biologically evaluated. Two compounds showed promising activities in both enzymatic and cellular assays. Moreover, one of them exhibited the capability to cross the blood-brain barrier as assessed by the parallel artificial membrane permeability assay. PMID:22209418

Chiriano, Gianpaolo; De Simone, Angela; Mancini, Francesca; Perez, Daniel I; Cavalli, Andrea; Bolognesi, Maria Laura; Legname, Giuseppe; Martinez, Ana; Andrisano, Vincenza; Carloni, Paolo; Roberti, Marinella

2011-12-16

144

Chemical abundances of planetary nebulae from optical recombination lines - II. Abundances derived from collisionally excited lines and optical recombination lines  

NASA Astrophysics Data System (ADS)

In Paper I, we presented spectrophotometric measurements of emission lines from the ultraviolet (UV) to the far-infrared for 12 Galactic planetary nebulae (PNe) and derived nebular thermal and density structures using a variety of plasma diagnostics. The measurements and plasma diagnostic results are used in the current paper to determine elemental abundances in these nebulae. Abundance analyses are carried out using both strong collisionally excited lines (CELs) and weak optical recombination lines (ORLs) from heavy element ions. Assuming electron temperatures and densities derived from HI recombination spectra (line and continuum), we are able to determine the ORL C abundance relative to hydrogen for all the PNe in our sample, N and O abundances for 11 of them and Ne abundances for nine of them. In all cases, ORL abundances are found to be systematically higher than the corresponding values deduced from CELs. In NGC 40, the discrepancy between the abundances derived from the two types of emission line reaches a factor of 17 for oxygen. For the other 10 PNe, the discrepancies for oxygen vary from 1.6 to 3.1. In general, collisionally excited infrared fine-structure lines, which have excitation energies less than 103 K and consequently emissivities that are insensitive to electron temperature and temperature fluctuations, yield ionic abundances comparable to those derived from optical/UV CELs. For a given nebula, the discrepancies between the ORL and CEL abundances are of similar magnitude for different elements. In other words, relative abundance ratios such as C/O, N/O and Ne/O deduced from the traditional method based on strong CELs are comparable to those yielded by ORLs, for a wide range of ORL to CEL oxygen abundance ratios, varying from near unity to over a factor of 20. We have also determined ORL abundances relative to hydrogen for the third-row element magnesium for 11 nebulae in our sample. In strong contrast to the cases for second-row elements, Mg abundances derived from the MgII 3d-4f ?4481 ORL are nearly constant for all the PNe analysed so far and agree within the uncertainties with the solar photospheric value. In accordance with results from previous studies, the ORL to CEL abundance ratio is correlated with the difference between the electron temperatures derived from the [OIII] forbidden-line ratio, on the one hand, and from the hydrogen recombination Balmer discontinuity, on the other. We find that the discrepancy between the ORL and CEL abundances is correlated with nebular absolute diameter, surface brightness, the electron density derived from [SII] CELs, and excitation class. The results confirm that the dichotomy of temperatures and heavy elemental abundances determined from the two types of emission line, which has been widely observed in PNe, is a strong function of nebular evolution, as first pointed out by Garnett and Dinerstein. Our analyses show that temperature fluctuations and/or density inhomogeneities are incapable of explaining the large discrepancies between the heavy elemental abundances and electron temperatures determined from the two types of emission line. Our analyses support the bi-abundance model of Liu et al., who have proposed that PNe contain another previously unseen component of ionized gas which, highly enriched in heavy elements, has an electron temperature of <~103 K and emits strongly in recombination lines but not in CELs. Our determinations of low average emission temperatures from the observed line intensity ratios of HeI and OII ORLs lend further support to this scenario.

Liu, Y.; Liu, X.-W.; Barlow, M. J.; Luo, S.-G.

2004-10-01

145

Impact of zinc substitution on the structural and magnetic properties of chemically derived nanosized manganese zinc mixed ferrites  

Microsoft Academic Search

Mn(1-x)Zn(x)Fe(2)O(4) nanoparticles (x = 0-1) were synthesized by wet\\u000a chemical co-precipitation techniques. X-ray diffraction, transmission\\u000a electron microscopy and high-resolution transmission electron microscopy\\u000a were effectively utilized to investigate the different structural\\u000a parameters. The elemental analysis was conducted using energy-dispersive\\u000a spectrum and inductively coupled plasma analysis. The magnetic\\u000a properties such as magnetization and coercivity were measured using\\u000a vibrating sample magnetometer. The observed

E. Veena Gopalan; I. A. Al-Omari; K. A. Malini; P. A. Joy; D. Sakthi Kumar; Yasuhiko Yoshida; M. R. Anantharaman

2009-01-01

146

Derivation of new human embryonic stem cell lines reveals rapid epigenetic progression in vitro that can be prevented by chemical modification of chromatin.  

PubMed

Human embryonic stem cells (hESCs) are pluripotent cell types derived from the inner cell mass of human blastocysts. Recent data indicate that the majority of established female XX hESC lines have undergone X chromosome inactivation (XCI) prior to differentiation, and XCI of hESCs can be either XIST-dependent (class II) or XIST-independent (class III). XCI of female hESCs precludes the use of XX hESCs as a cell-based model for examining mechanisms of XCI, and will be a challenge for studying X-linked diseases unless strategies are developed to reactivate the inactive X. In order to recover nuclei with two active X chromosomes (class I), we developed a reprogramming strategy by supplementing hESC media with the small molecules sodium butyrate and 3-deazaneplanocin A (DZNep). Our data demonstrate that successful reprogramming can occur from the XIST-dependent class II nuclear state but not class III nuclear state. To determine whether these small molecules prevent XCI, we derived six new hESC lines under normoxic conditions (UCLA1-UCLA6). We show that class I nuclei are present within the first 20 passages of hESC derivation prior to cryopreservation, and that supplementation with either sodium butyrate or DZNep preserve class I nuclei in the self-renewing state. Together, our data demonstrate that self-renewal and survival of class I nuclei are compatible with normoxic hESC derivation, and that chemical supplementation after derivation provides a strategy to prevent epigenetic progression and retain nuclei with two active X chromosomes in the self-renewing state. PMID:22058289

Diaz Perez, Silvia V; Kim, Rachel; Li, Ziwei; Marquez, Victor E; Patel, Sanjeet; Plath, Kathrin; Clark, Amander T

2011-11-04

147

A rapid screening for cytochrome P450 catalysis on new chemical entities: cytochrome P450 BM3 and 1,2,5-oxadiazole derivatives.  

PubMed

This work presents the validation of a rapid screening procedure for the catalysis of cytochrome P450 on new chemical entities. The assay is tested on the prototypical, catalytically self-sufficient and soluble cytochrome P450 BM3 from Bacillus megaterium that shares a high degree of homology with mammalian counterparts. The so-called alkali assay developed in our laboratory is validated here also by product formation and molecular modeling on a number of derivatives sharing the molecular scaffold of the 1,2,5-oxadiazole ring, a class of molecules very different from the long-chain fatty acids known to be oxidized by cytochrome P450 BM3. The alkali assay reveals the ability of this cytochrome to oxidize NADPH in the presence of nine out of thirteen 1,2,5-oxadiazole derivatives tested. The enzyme shows high affinity and coupling efficiencies when incubated with four 1,2,5-oxadiazole derivatives. The presence of oxidation products deriving from catalysis was also confirmed by high-performance liquid chromatography (HPLC). Molecular docking suggests that a key factor for the 1,2,5-oxadiazole derivatives to enter the active site and induce catalysis is the presence of the -SO(2) moiety bridging the 1,2,5-oxadiazole and phenyl rings. These data indicate that the alkali assay is able to quickly and cheaply detect the recognition of new substrates by cytochrome P450. The assay is not intended to substitute HPLC-mass spectrometry analysis, but it is a preliminary screening that allows elimination of obvious nonsubstrates from the start. PMID:22983164

Tsotsou, Georgia E; Di Nardo, Giovanna; Sadeghi, Sheila J; Fruttero, Roberta; Lazzarato, Loretta; Bertinaria, Massimo; Gilardi, Gianfranco

2012-09-13

148

40 CFR 721.1820 - Bisphenol derivative.  

Code of Federal Regulations, 2010 CFR

...2009-07-01 2009-07-01 false Bisphenol derivative. 721.1820 Section 721...Chemical Substances § 721.1820 Bisphenol derivative. (a) Chemical substance...chemical substance identified generically as bisphenol derivative (PMN No....

2009-07-01

149

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

SciTech Connect

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.

Shiquan Tao

2006-12-31

150

Chemical inhibitors suggest endophytic fungal paclitaxel is derived from both mevalonate and non-mevalonate-like pathways.  

PubMed

Taxus trees possess fungal endophytes reported to produce paclitaxel. Inhibitors that block early steps in plant paclitaxel biosynthesis were applied to a paclitaxel-producing fungus to determine whether these steps are shared. The plant paclitaxel backbone is reportedly derived from the non-mevalonate terpenoid pathway, while the side chain is phenylalanine-derived. Evidence that the shikimate pathway contributes to fungal paclitaxel was shown by decreased paclitaxel accumulation following inhibition of phenylalanine ammonia lyase. Expression of another shikimate pathway enzyme, 3-dehydroquinate synthase, coincided with paclitaxel production. The importance of the mevalonate pathway in fungal paclitaxel biosynthesis was shown by inhibition of fungal paclitaxel accumulation using compactin, a specific inhibitor of 3-hydroxy-3-methyl-glutaryl-CoA reductase. Expression of another mevalonate pathway enzyme, 3-hydroxy-3-methyl-glutaryl-CoA synthase, coincided with fungal paclitaxel accumulation. Unexpectedly, results from using fosmidomycin suggested that fungal paclitaxel requires 1-deoxy-D-xylulose-5-phosphate reductoisomerase (DXR), an enzyme in the 2-C-methyl-D-erythritol-4-phosphate (MEP) pathway normally found in bacteria/plants. Additional lines of evidence support this finding; first, a plant DXR antibody recognized a fungal peptide of the correct size; second, expression of an apparent fungal DXR ortholog correlated to changes in paclitaxel production; finally, BLAST searching identified a gene putatively encoding 1-deoxy-D-xylulose-5-phosphate synthase, the first enzyme in the MEP pathway in Aspergillus. PMID:22103292

Soliman, Sameh S M; Tsao, Rong; Raizada, Manish N

2011-11-21

151

Chemical modification of silica gel with synthesized new Schiff base derivatives and sorption studies of cobalt (II) and nickel (II)  

NASA Astrophysics Data System (ADS)

In this study, three Schiff base ligands and their complexes were synthesized and characterized by infrared spectroscopy (IR), thermogravimetric analyses (TGA), nuclear magnetic resonance (NMR), elemental analysis and magnetic susceptibility apparatuses. Silica gel was respectively modified with Schiff base derivatives, (E)-2-[(2-chloroethylimino)methyl]phenol, (E)-4-[(2-chloroethylimino)methyl]phenol and N, N'-[1,4-phenilendi(E)methylidene]bis(2-chloroethanamine), after silanization of silica gel by (3-aminopropyl)trimethoxysilane (APTS) by using a suitable method. Characterization of the surface modification was also performed with IR, TGA and elemental analysis. The immobilized surfaces were used for Co(II) and Ni(II) sorption from aqueous solutions and values of sorption were detected by atomic absorption spectrometer (AAS).

Kursunlu, Ahmed Nuri; Guler, Ersin; Dumrul, Hakan; Kocyigit, Ozcan; Gubbuk, Ilkay Hilal

152

Pinpointing pseurotins from a marine-derived Aspergillus as tools for chemical genetics using a synthetic lethality yeast screen.  

PubMed

A new compound of mixed polyketide synthase-nonribosomal peptide synthetase (PKS/NRPS) origin, 11- O-methylpseurotin A ( 1), was identified from a marine-derived Aspergillus fumigatus. Bioassay-guided fractionation using a yeast halo assay with wild-type and cell cycle-related mutant strains of Saccharomyces cerevisiae resulted in the isolation of 1, which selectively inhibited a Hof1 deletion strain. Techniques including 1D and 2D NMR, HRESIMS, optical rotation, J-based analysis, and biosynthetic parallels were used in the elucidation of the planar structure and absolute configuration of 1. A related known compound, pseurotin A ( 2), was also isolated and found to be inactive in the yeast screen. PMID:17929896

Boot, Claudia M; Gassner, Nadine C; Compton, Jennifer E; Tenney, Karen; Tamble, Craig M; Lokey, R Scott; Holman, Theodore R; Crews, Phillip

2007-10-12

153

Modeling and experimental verification of physical and chemical processes during pyrolysis of a refuse-derived fuel  

SciTech Connect

A model for refuse-derived fuel (RDF) conventional pyrolysis in a fixed-bed reactor is presented. The model investigates the influence of the heat- and mass-transfer processes on the pyrolysis product yields. Solid degradation reactions have been modeled by assuming that the interactions between the main RDF components during pyrolysis are negligible and that the RDF pyrolysis behavior may be considered as the sum of the separate behaviors of primary reacting species. The model accounts for conductive and convective heat transfer within the solid matrix and secondary tar-cracking reactions, as well as for variability in physical properties and in the void fraction of the pyrolyzing material. Quite good agreement was found between model results and experimental data obtained for conventional pyrolysis of a RDF in a laboratory-scale fixed-bed reactor. The model is able to predict the temperature transients, the rate of gas generation, and the product final yields during conventional pyrolysis of RDF.

Cozzani, V.; Tognotti, L. [Univ. degli Studi di Pisa (Italy); Nicolella, C.; Rovatti, M. [Univ. degli Studi di Genova (Italy). Ist. di Scienze e Tecnologie dell`Ingegneria Chimica

1996-01-01

154

Atmospheric pressure chemical vapor infiltration (CVI) for the preparation of biomorphic SiC ceramics derived from paper.  

PubMed

Chemical Vapor Infiltration of biological structures such as paper is used here to produce biomorphic SiC ceramics with high temperature resistance. The biological substrate materials are infiltrated with tetramethylsilane (TMS) at atmospheric pressure and elevated temperatures of 790 degrees C. A simple tube furnace (hot-wall reactor) is used for the infiltration process. As result, porous SiC-ceramics are grown which are around 20% smaller and 70% lighter than the initial substrates. This can be explained by the pyrolytic reaction of the substrates while heating them up to 790 degrees C, which is necessary for the infiltration process. Nevertheless, besides the shrinking of the substrates the geometrical form remains nearly unchanged. The resulting materials were heated up to 1000 degrees C in oxygen atmosphere in order to analyze their resistance against oxidation. After this treatment, all of them were still mechanically stable and of unchanged shape while a further mass loss was observed. This confirms the high temperature stability of the prepared materials. PMID:22097596

Pflitsch, Christian; Curdts, Benjamin; Atakan, Burak

2011-09-01

155

Enhanced Durability of Antisticking Layers by Recoating a Silica Surface with Fluorinated Alkylsilane Derivatives by Chemical Vapor Surface Modification  

NASA Astrophysics Data System (ADS)

Adsorbed monolayers from (3,3,3-trifluoropropyl)trimethoxysilane (FAS3), (tridecafluoro-1,1,2,2-tetrahydrooctyl)trimethoxysilane (FAS13), (heptadecafluoro-1,1,2,2-tetrahydrodecyl)trimethoxysilane (FAS17), and (heptadecafluoro-1,1,2,2-tetrahydrodecyl)trichlorosilane (FAS17-Cl) were formed by chemical vapor surface modification (CVSM) on silica lens surfaces cleaned by exposure to vacuum ultraviolet (VUV) light at 172 nm. Changes in monolayer-modified lens surfaces concomitant with repeating a cycle of curing to induce the radical polymerization of a UV-curable resin and detaching the UV-cured resin were monitored by contact angle measurement with water and atomic force microscopy to investigate the property of the adsorbed monolayers as antisticking layers in UV nanoimprint lithography. A decrease of the contact angle for water with increasing the number of repeated cycles was mainly responsible for the removal of surface impurities in the form of nanoparticles on detaching the cured resin repeatedly. It was found that recoating the silica lens surface with monolayers from FAS13, FAS17, and FAS17-Cl after cleaning by VUV-light exposure resulted in the suppression of the decrease in the contact angle. These results indicate that the durability of an antisticking layer in UV nanoimprint lithography is markedly improved by the recoating.

Akihiro Kohno,; Nobuji Sakai,; Shinji Matsui,; Masaru Nakagawa,

2010-06-01

156

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

PubMed

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

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

2001-01-01

157

Chemical epigenetics alters the secondary metabolite composition of guttate excreted by an atlantic-forest-soil-derived Penicillium citreonigrum.  

PubMed

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 muM 5-azacytidine (a DNA methyltransferase inhibitor) was 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

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

2010-05-28

158

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

PubMed Central

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.

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

2010-01-01

159

Recombinant leech-derived tryptase inhibitor: construction, production, protein chemical characterization and inhibition of HIV-1 replication.  

PubMed

A synthetic gene coding for leech-derived tryptase inhibitor, form C (LDTI-C), was designed, cloned and expressed. The gene assembled via 6 oligonucleotides contains linker sequences, stop codons and internal restriction recognition sites for cloning, expression and cassette mutagenesis. Periplasmatic expression products could not be detected in Escherichia coli (E. coli), but strong expression was found using Saccharomyces cerevisiae (S. cerevisiae) ( > 10 mg/l culture broth) if a variant of pVT102U/alpha was used as vector. The secreted material was isolated after cross-flow filtration and purified by cation exchange chromatography. The recombinant material proved to be pure and homogeneous by electrophoretic and chromatographic analyses. Amino acid sequencing and molecular mass determination (4737.6 +/- 0.77 Da) by electrospray ionization mass spectrometry confirmed that rLDTI-C was processed correctly and that it is indistinguishable from LDTI-C. The far UV-CD (circular dichroism) spectrum of the recombinant inhibitor is typical for a small folded protein. rLDTI-C is inhibitorily fully active, its complexes with bovine trypsin and human mast cell tryptase display equilibrium dissociation constants which are nearly identical to those with the natural inhibitor. Remarkably, the inhibitor blocked replication of HIV-1 in HUT-78 cells at a concentration of 20 microM. PMID:7888082

Auerswald, E A; Morenweiser, R; Sommerhoff, C P; Piechottka, G P; Eckerskorn, C; Gürtler, L G; Fritz, H

1994-10-01

160

The effect of adipose tissue derived MSCs delivered by a chemically defined carrier on full-thickness cutaneous wound healing.  

PubMed

Mesenchymal stem cells (MSCs) have properties which make them promising for the treatment of chronic non-healing wounds. A major so far unmet challenge is the efficient, safe and painless delivery of MSCs to skin wounds. Recently, a surface carrier of medical-grade silicone coated by plasma polymerisation with a thin layer of acrylic acid (ppAAc) was developed, and shown to successfully deliver MSCs to deepithelialised human dermis in vitro. Here we studied the potential of the ppAAc carrier to deliver human adipose tissue derived MSCs (AT-MSCs) to murine full-thickness excisional skin wounds in vivo. Further we investigate the mechanism of action of MSCs in accelerating wound healing in these wounds. AT-MSCs cultured on ppAAc carriers for 4 days or longer fully retained their cell surface marker expression profile, colony-forming-, differentiation- and immunosuppressive potential. Importantly, AT-MSCs delivered to murine wounds by ppAAc carriers significantly accelerated wound healing, similar to AT-MSCs delivered by intradermal injection. More than 80% of AT-MSCs were transferred from carriers to wounds in 3 days. AT-MSCs were detectable in wounds for at least 5 days after wounding. Carrier delivered AT-MSCs were demonstrated to have the capacity to down-modulate TNF-?-dependent inflammation, increase anti-inflammatory M2 macrophage numbers, and induce TGF-?(1)-dependent angiogenesis, myofibroblast differentiation and granulation tissue formation, thereby enhancing overall tissue repair. PMID:23317813

Jiang, Dongsheng; Qi, Yu; Walker, Nathan G; Sindrilaru, Anca; Hainzl, Adelheid; Wlaschek, Meinhard; MacNeil, Sheila; Scharffetter-Kochanek, Karin

2013-01-11

161

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

SciTech Connect

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

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

1981-01-01

162

Differential polarization of alveolar macrophages and bone marrow-derived monocytes following chemically and pathogen-induced chronic lung inflammation  

PubMed Central

Alveolar macrophages and BDMCs undergo sequential biochemical changes during the chronic inflammatory response to chemically induced lung carcinogenesis in mice. Herein, we examine two chronic lung inflammation models—repeated exposure to BHT and infection with Mycobacterium tuberculosis—to establish whether similar macrophage phenotype changes occur in non-neoplastic pulmonary disease. Exposure to BHT or M. tuberculosis results in pulmonary inflammation characterized by an influx of macrophages, followed by systemic effects on the BM and other organs. In both models, pulmonary IFN-? and IL-4 production coincided with altered polarization of alveolar macrophages. Soon after BHT administration or M. tuberculosis infection, IFN-? content in BALF increased, and BAL macrophages became classically (M1) polarized, as characterized by increased expression of iNOS. As inflammation progressed in both models, the amount of BALF IFN-? content and BAL macrophage iNOS expression decreased, and BALF IL-4 content and macrophage arginase I expression rose, indicating alternative/M2 polarization. Macrophages present in M. tuberculosis-induced granulomas remained M1-polarized, implying that these two pulmonary macrophage populations, alveolar and granuloma-associated, are exposed to different activating cytokines. BDMCs from BHT-treated mice displayed polarization profiles similar to alveolar macrophages, but BDMCs in M. tuberculosis-infected mice did not become polarized. Thus, only alveolar macrophages in these two models of chronic lung disease exhibit a similar progression of polarization changes; polarization of BDMCs was specific to BHT-induced pulmonary inflammation, and polarization of granuloma macrophages was specific to the M. tuberculosis infection.

Redente, Elizabeth F.; Higgins, David M.; Dwyer-Nield, Lori D.; Orme, Ian M.; Gonzalez-Juarrero, Mercedes; Malkinson, Alvin M.

2010-01-01

163

[Studies on the chemical constituents of Aquilaria sinensis(Lour.) Gilg. IV. Isolation and characterization of 2-(2-phenylethyl)chromone derivatives].  

PubMed

Six chromone derivatives were isolated from the ether soluble fraction of the alcoholic extract of Aquilaria sinensis(Lour.) Gilg. (Thymeleaceae) by silica gel chromatography. On the basis of spectrometric data (UV, IR, 1HNMR and 13CNMR as well as MS) and chemical synthesis one of them was found to be a new chromone, 6-hydroxy-2-[2-(4'-methoxylphenyl)ethyl]chromone(VI) and the other five known chromones are 2-(2-phenylethyl)chromone(I), 6-methoxy-2-(2-phenylethyl)chromone (II), 6.7-dimethoxy-2-(2-phenylethyl)chromone(III), 6-methoxy-2[2-(3'-methoxyphenyl)ethyl]chromone(IV) and 6-hydroxy-2-(2-phenylethyl) chromone(V). These compounds were obtained for the first time from this plant. PMID:2618717

Yang, J S; Wang, Y L; Su, Y L

1989-01-01

164

Microwave plasma enhanced chemical vapor deposition growth of few-walled carbon nanotubes using catalyst derived from an iron-containing block copolymer precursor  

NASA Astrophysics Data System (ADS)

The microwave plasma enhanced chemical vapor deposition (MPECVD) method is now commonly used for directional and conformal growth of carbon nanotubes (CNTs) on supporting substrates. One of the shortcomings of the current process is the lack of control of the diameter and diameter distribution of the CNTs due to difficulties in synthesizing well-dispersed catalysts. Recently, block copolymer derived catalysts have been developed which offer the potential of fine control of both the size of and the spacing between the metal clusters. In this paper we report the successful growth of CNTs with narrow diameter distribution using polystyrene-block-polyferrocenylethylmethylsilane (PS-b-PFEMS) as the catalyst precursor. The study shows that higher growth pressure leads to better CNT growth. Besides the pressure, the effects on the growth of CNTs of the growth parameters, such as temperature and precursor gas ratio, are also studied.

Wang, Peng; Lu, Jennifer; Zhou, Otto

2008-05-01

165

Identification of human-derived volatile chemicals that interfere with attraction of the Scottish biting midge and their potential use as repellents.  

PubMed

The Scottish biting midge, Culicoides impunctatus (Diptera: Ceratopogonidae), is a major pest in Scotland, causing a significant impact to the Scottish tourist and forestry industries. C. impunctatus is a generalist feeder, preferring to feed on large mammals, and is notorious for its attacks on humans. Until now, there was anecdotal evidence for differential attraction of female host-seeking C. impunctatus to individual human hosts, and the mechanism for this phenomenon was unknown. Using extracts of human odor collected by air entrainment, electroantennogram recordings to identify the physiologically active components, followed by behavioral assays, we show, for the first time, the differential attraction of female C. impunctatus to human odors and the chemical basis for this phenomenon. Certain chemicals, found in greater amounts in extracts that cause low attractiveness to midges, elicit a repellent effect in laboratory assays and repellency trials in the field. Differences in the production of these natural human-derived compounds could help to explain differential "attractiveness" between different human hosts. A mixture of two compounds in particular, 6-methyl-5-hepten-2-one and geranylacetone [(E)-6,10-dimethylundeca-5,9-dien-2-one], showed significant repellency (87, 77.4, 74.2, and 31.6% at hours 0, 1, 2, and 3, respectively) in the field and have the potential to be developed as novel repellents. PMID:19351071

Logan, James G; Seal, Nicola J; Cook, James I; Stanczyk, Nina M; Birkett, Michael A; Clark, Suzanne J; Gezan, Salvador A; Wadhams, Lester J; Pickett, John A; Mordue, A Jennifer

2009-03-01

166

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

PubMed Central

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

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

2013-01-01

167

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

PubMed

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

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

2012-07-13

168

Chemical microsensors  

DOEpatents

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.

Li, DeQuan (Los Alamos, NM); Swanson, Basil I. (Los Alamos, NM)

1995-01-01

169

Neuroprotective Ganglioside Derivatives.  

National Technical Information Service (NTIS)

In this study, neuroprotective ganglioside derivatives are studied in an attempt to devise neuroprotective agents targeted to specific points in cell death pathways. GMl ganglioside and several of its chemically modified derivatives are neuroprotective in...

M. D. Ullman

2004-01-01

170

Are 4-hydroxy-2(E)-nonenal derived mercapturic acids and (1)H NMR metabonomics potential biomarkers of chemically induced oxidative stress in the kidney?  

PubMed

Various markers derived from radical-mediated oxidative damage to cellular macromolecules have been proposed as tools for the detection of alterations in redox status, but there is strong debate as to which may be the most sensitive and reliable indicator of oxidative stress conditions. This study was aimed to investigate the use of mercapturic acids derived from conjugation of the lipid peroxidation product 4-hydroxy-2(E)-nonenal (HNE) with glutathione and (1)H NMR metabonomics in two rodent models of oxidative kidney damage. Treatment of rats with FeNTA resulted in a marked increase in the concentrations of 4-hydroxy-2(E)-nonenal derived mercapturic acids in plasma and kidney within 5h. 1,4-dihydroxynonenal mercapturic acid (DHN-MA) remained elevated 24h after compound administration, while other markers returned to control levels, suggesting that DHN-MA may present a more stable indicator of lipid peroxidation. However, significant changes were only evident in the presence of severe nephrotoxicity, indicating that HNE-derived mercapturic acids were less sensitive than nonspecific markers of renal injury. In contrast to FeNTA, continuous administration of potassium bromate for 2 weeks had no effect on the concentrations of DHN-MA or 4-hydroxyononenal-3-yl-mercapturic acid in kidney, plasma or urine of treated animals, although a dose-dependent increase in 8-oxo-7,8-dihydro-2'deoxyguanosine was observed in kidney DNA in the absence of nephrotoxicity. These data suggest that markers of lipid peroxidation may not be suitable to detect alterations in redox status induced by potassium bromate at doses known to cause tumors after chronic treatment. Alterations in urine (1)H NMR spectra were detected in both models but reflect nonspecific alterations as a result of impaired renal function rather than specific changes indicative of oxidative stress. In summary, it appears that - depending on the pathological circumstances and the chemical nature of the insult - different types of oxidative stress exist, and it is therefore not possible to define a universal marker of oxidative stress. PMID:17184893

Mally, Angela; Amberg, Alexander; Hard, Gordon C; Dekant, Wolfgang

2006-12-01

171

Enhanced ferroelectric properties in Mn-doped K0.5Na0.5NbO3 thin films derived from chemical solution deposition  

NASA Astrophysics Data System (ADS)

Mn-doped K0.5Na0.5NbO3 (KNN) thin films derived from chemical solution deposition have been investigated. 2 mol % manganese acetate was introduced into the polyvinylpyrrolidone-modified KNN precursor solution to prepare the KNN thin films. It was found that Mn doping can increase the dielectric constant and decrease the dielectric loss, as well as significantly decrease the leakage current. The leakage current density of Mn-doped KNN film is about 3×10-6 A/cm2 at an electric field of 50 kV/cm, which is 104 times lower than that of the undoped film (about 3×10-2 A/cm2). These are attributed to the decrease in the concentration in oxygen vacancies and free carrier-holes by increasing the valence of Mn during thermal treatment. As a result, well saturated polarization-electric field hysteresis loops were obtained in the Mn-doped KNN thin films.

Wang, Lingyan; Ren, Wei; Shi, Peng; Chen, Xiaofeng; Wu, Xiaoqing; Yao, Xi

2010-08-01

172

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

SciTech Connect

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.

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

1994-06-01

173

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

SciTech Connect

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.

Brothers, Michael C [University of Illinois, Urbana-Champaign; Nesbitt, Anna E [University of Illinois, Urbana-Champaign; Hallock, Michael J [University of Illinois, Urbana-Champaign; Rupasinghe, Sanjeewa [University of Illinois, Urbana-Champaign; Tang, Ming [University of Illinois, Urbana-Champaign; Harris, Jason B [ORNL; Baudry, Jerome Y [ORNL; Schuler, Mary A [University of Illinois, Urbana-Champaign; Rienstra, Chad M [University of Illinois, Urbana-Champaign

2011-01-01

174

Correlation between refractive indices and other fuel-related physical/chemical properties of pyrolysis liquids derived from coal, oil shale, and tar sand  

SciTech Connect

In the literature, characterization techniques based upon the liquid's refractive index are used with petroleum distillates to predict fuel-related properties; however, essentially nothing has been reported on the application of this technique to pyrolysis liquids. Measurements of the refractive indices of the pyrolysis liquids derived from various feedstocks (coal, oil shale, and tar sand) were made and appear to correlate well with the liquids' physical and chemical properties. The refractive indices of the pyrolysis liquids show good correlations with liquid density (correlation coefficient of 0.98), carbon and proton aromaticities (correlation coefficients of 0.88 and 0.91, respectively), and liquid carbon residue (i.e., correlation coefficient of 0.88 with the Conradson carbon residue). The above and other correlations were developed using data from at least 7 to as many as 35 discrete samples. These correlations have been used to develop empirical models. These findings demonstrate the potential of using the liquid's refractive index as a rapid technique to characterize the fuel-related properties of fossil fuel liquids generated by pyrolysis (before they are hydrogenated).

Khan, M.R. (Department of Energy, Morgantown, WV (USA))

1988-01-01

175

THE RELATION OF CHEMICAL STRUCTURE IN CATECHOL COMPOUNDS AND DERIVATIVES TO POISON IVY HYPERSENSITIVENESS IN MAN AS SHOWN BY THE PATCH TEST.  

PubMed

1. Additional evidence is presented in support of the view which postulates a close chemical and biologic relation between the active ingredients in poison ivy and Japan lac. 2. Biologic evidence, based on the use of the patch test in man, is presented in support of the view that the active ingredient in poison ivy is a catechol derivative with a long, unsaturated side-chain in the 3-position. 3. Of the catechol compounds and derivatives studied, group reactions in patients sensitive to poison ivy leaves or extract were exhibited by the following compounds: 3-pentadecyl catechol (100 per cent of 21 cases), 4-pentadecyl catechol (38 per cent of 21 cases), "urushiol" dimethyl ether (33 per cent of 33 cases), 3-pentadecenyl-1'-veratrole (21 per cent of 14 cases), 3-methyl catechol (14 per cent of 21 cases), and hydrourushiol dimethyl ether (10 per cent of 20 cases). It has been found that 3-geranyl catechol shows a practically constant group reactivity in persons sensitive to poison ivy. 4. The uniformly positive group reaction to 3-pentadecyl catechol is notable since this substance possesses a saturated side-chain, whereas the active ingredient in poison ivy is known to have an unsaturated side-chain. 5. The group reactivity was not restricted to the 3-position, for in some instances 4-pentadecyl catechol also gave group reactions which, however, were less intense and less frequent than those shown by 3-pentadecyl catechol. This indicates that in some cases a long side-chain in the 4 position may be effective in producing group specific reactions. 6. Only an occasional person showed sensitiveness to 3-methyl catechol (short side-chain), and in one instance the group reactivity appeared to be specific for the 3-position. 7. The position of the side-chain in the catechol configuration has some bearing on the degree and incidence of group reactions in persons hypersensitive to poison ivy. 8. Evidence is presented to indicate that the introduction of double bonds in the alkyl side-chain increases the incidence and intensity of group reactions. 9. Methylating the hydroxyl groups in the catechol configuration diminishes strongly the incidence of group reactivity but does not eliminate it entirely in persons hypersensitive to poison ivy. Thus, "urushiol" dimethyl ether (3-pentadecadienyl veratrole) gave group reactions in 33 per cent of 33 persons. 10. Methylating the hydroxyl groups as well as saturating the double bonds in the alkyl side-chain still further diminishes the group reactions but an occasional person hypersensitive to poison ivy may still show positive reaction to such a substance as 3-pentadecyl veratrole (hydrourushiol dimethyl ether). In this respect our results are not in full agreement with those recorded by Toyama who stated that hydrourushiol dimethyl ether is entirely harmless. 11. The significance of the group reactivity displayed by certain veratrole compounds is discussed, and several possible explanations of their behavior are advanced. 12. The group reactions discussed in this paper relate only to various catechol and veratrole compounds. Preliminary studies by us indicate that this sensitiveness extends to other phenolic derivatives. 13. Among the veratrole compounds showing positive reactions, the order of frequency and intensity was: (1) "urushiol" dimethyl ether (average of two double bonds); (2) S-pentadecenyl-1'-veratrole (one double bond); (3) hydrourushiol dimethyl ether (saturated side-chain). It may be noted that 4-pentadecyl veratrole was inactive. PMID:19871415

Keil, H; Wasserman, D; Dawson, C R

1944-10-01

176

Secondary structure of ?-hydroxydecanoyl thiol ester dehydrase, a 39-kDa protein, derived from H ? , C ? , C ? and CO signal assignments and the Chemical Shift Index: Comparison with the crystal structure  

Microsoft Academic Search

Nearly complete backbone 1H, 15N and 13C signal assignments are reported for ß-hydroxydecanoyl thiol ester dehydrase, a 39-kDa homodimer containing 342 amino acids. Although 15N relaxation data show that the protein has a rotational correlation time of 18 ns, assignments were derived from triple-resonance experiments recorded at 500 MHz and pH 6.8, without deuteration. The Chemical Shift Index, CSI, identified

Valérie Copié; John A. Battles; John M. Schwab; Dennis A. Torchia

1996-01-01

177

Gas chromatography/mass spectrometric analysis of N,N-dialkylaminoethyl-2-chlorides and trimethylsilyl derivatives of N,N-dialkylaminoethan-2-ols for verification of the Chemical Weapons Convention.  

PubMed

Gas chromatography/electron ionization mass spectrometry (GC/EI-MS) of N,N-dialkylaminoethyl-2-chlorides (DAAECls) and trimethylsilyl (TMS) derivatives of N,N-dialkylaminoethan-2-ols (DAAEAs) has been carried out. GC/EI-MS data of these compounds are of importance for verification of the Chemical Weapons Convention (CWC). Based on these EI mass spectra, generalized fragmentation routes are proposed that rationalize most of the characteristic ions. PMID:16773673

Gupta, Arvinda K; Pardasani, Deepak; Kanaujia, Pankaj K; Tak, Vijay; Dubey, Devendra K

2006-01-01

178

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

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.

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

1984-01-01

179

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)

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.

Tao, Shiquan

2010-03-01

180

Studies on chemical modification and biology of a natural product, gambogic acid (II): Synthesis and bioevaluation of gambogellic acid and its derivatives from gambogic acid as antitumor agents  

Microsoft Academic Search

Gambogic acid (GA) has been reported to be a potent apoptosis inducer. The fact that it is amenable to chemical modification makes GA an attractive molecule for the development of anticancer agents. We firstly reported the synthesis of gambogellic acid, which was generated under acid catalysis from readily available GA by a base-catalyzed diene intramolecular annelation. Sequentially, thirteen new compounds

Jinxin Wang; Junhai Ma; Qidong You; Li Zhao; Fan Wang; Chong Li; Qinglong Guo

2010-01-01

181

Study on the fate of petroleum-derived polycyclic aromatic hydrocarbons (PAHs) and the effect of chemical dispersant using an enclosed ecosystem, mesocosm  

Microsoft Academic Search

Polycyclic Aromatic Hydrocarbons (PAHs) are one of the components found in oil and are of interest because some are toxic. We studied the environmental fate of PAHs and the effects of chemical dispersants using experimental 500 l mesocosm tanks that mimic natural ecosystems. The tanks were filled with seawater spiked with the water-soluble fraction of heavy residual oil. Water samples

Mihoko Yamada; Hideshige Takada; Keita Toyoda; Akihiro Yoshida; Akira Shibata; Hideaki Nomura; Minoru Wada; Masahiko Nishimura; Ken Okamoto; Kouichi Ohwada

2003-01-01

182

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...

183

GC\\/MS analysis of trimethylsilyl derivatives of treaty-related chemical warfare agent degradation products. Final report, May-August 1994  

Microsoft Academic Search

The entry into force of the Chemical Weapons Convention requires specific detection methods for identification of CW agent degradation products to verify treaty compliance or noncompliance. Many of these products are polar and not detected in the original state by gas chromatography based instrumentation. In this study, 22 compounds, including 4 alkylphosphonic acids (methyl, ethyl, n-propyl, and t-butyl) and 18

Rohrbaugh

1995-01-01

184

Size distribution, mass concentration, chemical and mineralogical composition and derived optical parameters of the boundary layer aerosol at Tinfou, Morocco, during SAMUM 2006  

Microsoft Academic Search

During the SAMUM 2006 field campaign in southern Morocco, physical and chemical properties of desert aerosols were measured. Mass concentrations ranging from 30 ? gm ?3 for PM2.5 under desert background conditions up to 300 000 ? gm ?3 for total suspended particles (TSP) during moderate dust storms were measured. TSP dust concentra- tions are correlated with the local wind

K. K ANDLER; C. D EUTSCHER; M. E B E RT; H. H OFM; A NN; R. JA ENICKE; P. K NIPPERTZ; K. L IE; A. M A SSLING; A. P ETZOLD; A. S CHLADITZ; B. W E IN; A. W IEDENSOHLER; S. W E IN; B RU C H

185

Derivation of multipotent nestin + \\/CD271 ? \\/STRO-1 ? mesenchymal-like precursors from human embryonic stem cells in chemically defined conditions  

Microsoft Academic Search

The successful establishment of stem cell-based therapies requires multipotent, immunocompatible stem cells, highly efficient\\u000a strategies for direct differentiation, and most importantly, optimal culture conditions for large-scale expansion of such\\u000a cell populations. Other than adult tissues, human embryonic stem cells (hESCs) represent another infinitely expansible source\\u000a for mesenchymal stem cell (MSC) derivation. Here, we reproducibly derived a population of Nestin+\\/CD271?\\/STRO-1? mesenchymal-like

Rongrong Wu; Bin Gu; Xiaoli Zhao; Zhou Tan; Liangbiao Chen; Jiang Zhu; Ming Zhang

186

The anisotropic effect of functional groups in 1H NMR spectra is the molecular response property of spatial nucleus independent chemical shifts (NICS)--conformational equilibria of exo/endo tetrahydrodicyclopentadiene derivatives.  

PubMed

The inversion of the flexible five-membered ring in tetrahydrodicyclopentadiene (TH-DCPD) derivatives remains fast on the NMR timescale even at 103 K. Since the intramolecular exchange process could not be sufficiently slowed for spectroscopic evaluation, the conformational equilibrium is thus inaccessible by dynamic NMR. Fortunately, the spatial magnetic properties of the aryl and carbonyl groups attached to the DCPD skeleton can be employed in order to evaluate the conformational state of the system. In this context, the anisotropic effects of the functional groups in the (1)H NMR spectra prove to be the molecular response property of spatial nucleus independent chemical shifts (NICS). PMID:21152640

Kleinpeter, Erich; Lämmermann, Anica; Kühn, Heiner

2010-12-13

187

Determination of delta 9-tetrahydrocannabinol-11-oic acid in urine as its pentafluoropropyl-pentafluoropropionyl derivative by GC/MS utilizing negative ion chemical ionization.  

PubMed

A rapid and sensitive GC/MS method for the determination of delta 9-tetrahydrocannabinol-11-oic acid in urine is presented. Enzymically hydrolyzed urine was extracted with hexane/ethyl ether followed by a one-step derivatization procedure with a mixture of pentafluoropropionic anhydride and pentafluoropropanol. By using negative ion chemical ionization and selected ion monitoring, a 200-fold higher detectability was observed, compared with El or positive ion chemical ionization under the conditions used. Samples were analyzed with split injection on a fused silica capillary column with a total analysis time of less than four minutes. A deuterium labelled analogue was used as internal standard and the precision for the overall method was measured to 3.4% for a sample concentration of 230 ng/mL, and to 6.7% for 3 ng/mL. The minimum detectable amount was below 1 ng/mL. PMID:6314044

Karlsson, L; Jonsson, J; Aberg, K; Roos, C

188

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

Microsoft Academic Search

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

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

2002-01-01

189

Size distribution, mass concentration, chemical and mineralogical composition and derived optical parameters of the boundary layer aerosol at Tinfou, Morocco, during SAMUM 2006  

Microsoft Academic Search

ABSTRACT During the SAMUM 2006 field campaign in southern Morocco, physical and chemical properties of desert aerosols were measured. Mass concentrations ranging from 30mugm-3 for PM2.5 under desert background conditions up to 300000mugm-3 for total suspended particles (TSP) during moderate dust storms were measured. TSP dust concentrations are correlated with the local wind speed, whereas PM10 and PM2.5 concentrations are

K. Kandler; L. Schütz; C. Deutscher; M. Ebert; H. Hofmann; S. Jäckel; R. Jaenicke; P. Knippertz; K. Lieke; A. Massling; A. Petzold; A. Schladitz; B. Weinzierl; A. Wiedensohler; S. Zorn; S. Weinbruch

2009-01-01

190

Glycal Derivatives  

NASA Astrophysics Data System (ADS)

Glycals are unsaturated sugar derivatives in which the double bond engages the anomeric carbon atom. Such cyclic vinyl ethers are characterized by high reactivity, allowing for regio- and stereoselective transformations, directly or indirectly related to glycosylation, as well as to formation of carbon-carbon and carbon-heteroatom bonds at the anomeric center. This review provides a systematic survey of chemical synthetic methods, by which the carbon-carbon double bond is introduced next to the ring oxygen, in an endo- or exocyclic position. Some mechanistic aspects are discussed in relation to traditional methods of glycal preparation, which rely on elimination reactions. Glycal-to-glycal rearrangement and applications of organometallic chemistry and heteroatom-induced transformations for syntheses and activation of glycals are also highlighted.

Priebe, Waldemar; Fokt, Izabela; Grynkiewicz, Grzegorz

191

Synthesis of some fluorescent benzimidazole derivatives using cobalt(ii) hydroxide as highly efficient catalyst - spectral and physico-chemical studies and ESIPT process.  

PubMed

Some fluorescent benzimidazole derivatives have been designed and synthesized using cobalt(ii) hydroxide as highly efficient catalyst. Synthesized compounds have been characterized by (1)H and (13)C-NMR and mass spectral analysis. The solvent effect on the absorption and fluorescence bands has been analyzed and supplemented by computational studies. Solvatochromic effects on the spectral position and profile of the stationary fluorescence spectra clearly indicate the charge transfer (CT) character of the emitting singlet states of all of the compounds studied in both polar and non-polar environments. The fluorescence decays for the benzimidazoles fit satisfactorily to a single exponential kinetics. HOMO and LUMO orbital pictures [DFT/B3LYP/6-31G(d,p)] evidence the existence of excited state intramolecular proton transfer (ESIPT) in benzimidazole derivatives containing a hydroxy group. PMID:23824328

Jayabharathi, J; Thanikachalam, V; Jayamoorthy, K

2013-10-23

192

Chemical synthesis of 2?-amino-5?-androstane-3?,17?-diol N-derivatives and their antiproliferative effect on HL60 human leukemia cells  

Microsoft Academic Search

Even though few steroids are used for the treatment of leukemia, 2?-(4-methylpiperazinyl)-5?-androstane-3?,17?-diol (1) was recently reported for its ability to inhibit the proliferation of human leukemia HL-60 cells. With an efficient procedure that we had developed for the aminolysis of hindered steroidal epoxides, we synthesized a series of 2?-amino-5?-androstane-3?,17?-diol N-derivatives structurally similar to 1. Hence, the opening of 2,3?-epoxy-5?-androstan-17?-diol with

Dominic Thibeault; Jenny Roy; Patrick DeRoy; Donald Poirier

2008-01-01

193

[Studies on the chemical constituents of Aquilaria sinensis (Lour.) Gilg. V. Isolation and characterization of three 2-(2-phenylethyl) chromone derivatives].  

PubMed

Three 2-(2-phenylethyl) chromone derivatives were isolated from the ethyl acetate soluble fraction of the alcoholic extract of Aquilaria sinensis (Lous.) Gilg. (Thymeleaceae) by silica gel chromatography. Based on spectral data (UV, IR, 1HNMR, 13CNMR and MS) two of them are new compounds and their structures were identified as 5,8-dihydroxy-2-(2-p-methoxyphenylethyl) chromone (2) and 6,7-dimethoxy-2-(2-p-methoxyphenylethyl) chromone (3). The known compound siolated for the first time from this plant, was identified as 5,8-dihydroxy-2-(2-phenylethyl)-chromone (1). PMID:2101003

Yang, J S; Wang, Y L; Su, Y L

1990-01-01

194

Antitumour benzothiazoles. Part 15: The synthesis and physico-chemical properties of 2-(4-aminophenyl)benzothiazole sulfamate salt derivatives.  

PubMed

A series of sulfamate salt derivatives of the potent and selective 2-(4-aminophenyl)benzothiazole antitumour agents has been prepared and their evaluation as potential prodrugs for parenteral administration carried out. The salts were sparingly soluble under aqueous conditions (pH 4-9), and degradation to the active free amine was shown to occur under strongly acidic conditions. The salts were found to be markedly less active than their parent amines against sensitive human tumour cell lines in vitro. PMID:11327598

Shi, D F; Bradshaw, T D; Chua, M S; Westwell, A D; Stevens, M F

2001-04-23

195

Identification of a chemical probe for bromo and extra C-terminal bromodomain inhibition through optimization of a fragment-derived hit.  

PubMed

The posttranslational modification of chromatin through acetylation at selected histone lysine residues is governed by histone acetyltransferases (HATs) and histone deacetylases (HDACs). The significance of this subset of the epigenetic code is interrogated and interpreted by an acetyllysine-specific protein-protein interaction with bromodomain reader modules. Selective inhibition of the bromo and extra C-terminal domain (BET) family of bromodomains with a small molecule is feasible, and this may represent an opportunity for disease intervention through the recently disclosed antiproliferative and anti-inflammatory properties of such inhibitors. Herein, we describe the discovery and structure-activity relationship (SAR) of a novel, small-molecule chemical probe for BET family inhibition that was identified through the application of structure-based fragment assessment and optimization techniques. This has yielded a potent, selective compound with cell-based activity (PFI-1) that may further add to the understanding of BET family function within the bromodomains. PMID:23095041

Fish, Paul V; Filippakopoulos, Panagis; Bish, Gerwyn; Brennan, Paul E; Bunnage, Mark E; Cook, Andrew S; Federov, Oleg; Gerstenberger, Brian S; Jones, Hannah; Knapp, Stefan; Marsden, Brian; Nocka, Karl; Owen, Dafydd R; Philpott, Martin; Picaud, Sarah; Primiano, Michael J; Ralph, Michael J; Sciammetta, Nunzio; Trzupek, John D

2012-11-08

196

Identification of a Chemical Probe for Bromo and Extra C-Terminal Bromodomain Inhibition through Optimization of a Fragment-Derived Hit  

PubMed Central

The posttranslational modification of chromatin through acetylation at selected histone lysine residues is governed by histone acetyltransferases (HATs) and histone deacetylases (HDACs). The significance of this subset of the epigenetic code is interrogated and interpreted by an acetyllysine-specific protein–protein interaction with bromodomain reader modules. Selective inhibition of the bromo and extra C-terminal domain (BET) family of bromodomains with a small molecule is feasible, and this may represent an opportunity for disease intervention through the recently disclosed antiproliferative and anti-inflammatory properties of such inhibitors. Herein, we describe the discovery and structure–activity relationship (SAR) of a novel, small-molecule chemical probe for BET family inhibition that was identified through the application of structure-based fragment assessment and optimization techniques. This has yielded a potent, selective compound with cell-based activity (PFI-1) that may further add to the understanding of BET family function within the bromodomains.

2012-01-01

197

Study on the fate of petroleum-derived polycyclic aromatic hydrocarbons (PAHs) and the effect of chemical dispersant using an enclosed ecosystem, mesocosm.  

PubMed

Polycyclic Aromatic Hydrocarbons (PAHs) are one of the components found in oil and are of interest because some are toxic. We studied the environmental fate of PAHs and the effects of chemical dispersants using experimental 500 l mesocosm tanks that mimic natural ecosystems. The tanks were filled with seawater spiked with the water-soluble fraction of heavy residual oil. Water samples and settling particles in the tanks were collected periodically and 38 PAH compounds were analyzed by gas chromatography-mass spectrometry (GC-MS). Low molecular weight (LMW) PAHs with less than three benzene rings disappeared rapidly, mostly within 2 days. On the other hand, high molecular weight (HMW) PAHs with more than four benzene rings remained in the water column for a longer time, up to 9 days. Also, significant portions (10-94%) of HMW PAHs settled to the bottom and were caught in the sediment trap. The addition of chemical dispersant accelerated dissolution and biodegradation of PAHs, especially HMW PAHs. The dispersant amplified the amounts of PAHs found in the water column. The amplification was the greater for the more hydrophobic PAHs, with an enrichment factor of up to six times. The increased PAHs resulting from dispersant use overwhelmed the normal degradation and, as a result, higher concentrations of PAHs were observed in water column throughout the experimental period. We conclude that the addition of the dispersant could increase the concentration of water column PAHs and thus increase the exposure and potential toxicity for organisms in the natural environment. By making more hydrocarbon material available to the water column, the application of dispersant reduced the settling of PAHs. For the tank with dispersant, only 6% of chrysene initially introduced was detected in the sediment trap whereas 70% was found in the trap in the tank without dispersant. PMID:12787605

Yamada, Mihoko; Takada, Hideshige; Toyoda, Keita; Yoshida, Akihiro; Shibata, Akira; Nomura, Hideaki; Wada, Minoru; Nishimura, Masahiko; Okamoto, Ken; Ohwada, Kouichi

2003-01-01

198

Glucosamine-derived phospholipids in Escherichia coli. Structure and chemical modification of a triacyl glucosamine 1-phosphate found in a phosphatidylglycerol-deficient mutant.  

PubMed

Certain Escherichia coli mutants defective in phosphatidylglycerol biosynthesis accumulate novel glucosamine-derived phospholipids. We previously demonstrated that the simplest of these substance (lipid X) is a diacylglucosamine 1-phosphate bearing beta-hydroxymyristoyl groups at positions 2 and 3 (Takayama, K., Qureshi, N., Mascagni, P., Nashed, M. A., Anderson, L., and Raetz, C. R. H. (1983) J. Biol. Chem. 258, 7379-7385). We now report the structural characterization of a triacylglucosamine 1-phosphate (designated lipid Y) that is also found in these mutants. Hydrolyzates of Y contain 2 mol of beta-hydroxymyristate and 1 mol of palmitate/mol of glucosamine. In the lipid, one of the beta-hydroxymyristates is amide-linked at position 2, while the two other fatty acyl groups are ester-linked. Fast atom bombardment mass spectrometry is used to confirm that Y is a monosaccharide derivative and that the molecular weight of Y as the free acid (C50H96NO13P) is 950.29. Analysis of Y by proton NMR spectroscopy at 200 MHz reveals that the anomeric configuration is alpha. Further, one of the esterified fatty acid residues is attached to the 3 OH of the sugar, while the second is linked to an OH moiety of a hydroxymyristate. The 4 and 6 OH groups of the sugar are unsubstituted, as in E. coli lipid X. To establish the precise location of each esterified fatty acyl residue, we subjected Y to a very mild alkaline hydrolysis in the presence of triethylamine. This resulted in the selective removal of a single hydroxymyristoyl group. The triethylamine-treated derivative (lipid Y) has a molecular weight of 723. NMR spectroscopy of Y shows that the 3 OH of the sugar is no longer substituted, while the beta OH of the remaining amide-linked hydroxymyristate is still esterified with palmitate. On the basis of these findings, we propose that lipid Y has the same fundamental structure as lipid X, except for the additional presence of a palmitoyl moiety on the N-linked hydroxymyristate. Presumably, lipid Y is synthesized from X by a selective acylation reaction. PMID:6358219

Takayama, K; Qureshi, N; Mascagni, P; Anderson, L; Raetz, C R

1983-12-10

199

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

Code of Federal Regulations, 2013 CFR

...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...

2013-07-01

200

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

SciTech Connect

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.

Olsen, L.D.

1987-01-01

201

Chemical genomic screening of a Saccharomyces cerevisiae genomewide mutant collection reveals genes required for defense against four antimicrobial peptides derived from proteins found in human saliva.  

PubMed

To compare the effects of four antimicrobial peptides (MUC7 12-mer, histatin 12-mer, cathelicidin KR20, and a peptide containing lactoferricin amino acids 1 to 11) on the yeast Saccharomyces cerevisiae, we employed a genomewide fitness screen of combined collections of mutants with homozygous deletions of nonessential genes and heterozygous deletions of essential genes. When an arbitrary fitness score cutoffs of 1 (indicating a fitness defect, or hypersensitivity) and -1 (indicating a fitness gain, or resistance) was used, 425 of the 5,902 mutants tested exhibited altered fitness when treated with at least one peptide. Functional analysis of the 425 strains revealed enrichment among the identified deletions in gene groups associated with the Gene Ontology (GO) terms "ribosomal subunit," "ribosome biogenesis," "protein glycosylation," "vacuolar transport," "Golgi vesicle transport," "negative regulation of transcription," and others. Fitness profiles of all four tested peptides were highly similar, particularly among mutant strains exhibiting the greatest fitness defects. The latter group included deletions in several genes involved in induction of the RIM101 signaling pathway, including several components of the ESCRT sorting machinery. The RIM101 signaling regulates response of yeasts to alkaline and neutral pH and high salts, and our data indicate that this pathway also plays a prominent role in regulating protective measures against all four tested peptides. In summary, the results of the chemical genomic screens of S. cerevisiae mutant collection suggest that the four antimicrobial peptides, despite their differences in structure and physical properties, share many interactions with S. cerevisiae cells and consequently a high degree of similarity between their modes of action. PMID:23208710

Lis, Maciej; Bhatt, Sanjay; Schoenly, Nathan E; Lee, Anna Y; Nislow, Corey; Bobek, Libuse A

2012-12-03

202

Synthesis, antitumor activity, and chemical properties of silaplatin and related platinum (II) and platinum (IV) complexes derived from beta-silyl amines.  

PubMed

Platinum (II) and platinum (IV) coordination complexes derived from beta-silyl-substituted amines were prepared. The solubility of selected complexes in water and physiological saline was measured, and the effect of the beta-silicon on the reactivity of the complex in aqueous solution was determined by HPLC. The stabilities of selected silyl complexes were compared to the carbon analogues. The cyclic complexes 2a ("silaplatin") and its Pt(IV) analogue, 2b, were very active against L1210 leukemia in vivo. Both the platinum (II) complex 2a and the platinum (IV) complex 2b produced a significant number of cures over the dose range 10-40 mg/kg. The platinum (II) complex 2a, silaplatin, was very active in vivo against an L1210 leukemia subline that was resistant to cisplatin; 2a was also active, when given ip, against ic implanted L1210. The cyclobutanedicarboxylic acid complex 3c was synthesized; this complex was active against both cisplatin sensitive and resistant L1210 leukemia but was less potent than the analogous dichloro compound 2a. The acyclic platinum (II) and platinum (IV) complexes 1a,b were synthesized and unexpectedly found to be inactive in vivo against L1210 leukemia. More lipophilic silaplatin analogues were prepared--Pt(II) complex 2c and Pt(IV) complex 2d have one additional methylene carbon compared to 2a,b, whereas Pt(II) complex 2e and Pt(IV) complex 2f have two additional methylene carbons. Cyclization of the alkyl groups attached to the silicon gave the spiro bicyclic Pt(II) complexes 10a and 11a and the Pt(IV) complexes 10b and 11b. PMID:7562909

Anderson, W K; Kasliwal, R; Houston, D M; Wang, Y S; Narayanan, V L; Haugwitz, R D; Plowman, J

1995-09-15

203

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)

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.

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

2013-04-01

204

Chemical Changes  

NSDL National Science Digital Library

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

Jolley, Mr.

2005-10-25

205

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

Code of Federal Regulations, 2013 CFR

...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...

2013-07-01

206

Chemical intermediates and derivatives from oleyl alcohol  

Microsoft Academic Search

Several series of compounds were prepared from oleyl alcohol which may prove useful as lubricants and plasticizers. The reactions\\u000a involved addition to the double bond and replacement of the hydroxyl moiety. One series of compounds is characterized l-R?,\\u000a 9(10)R octadecane where l-R? signifies the replacement of hydroxyl by ethoxy,tert-butylphenyl,tert-butoxy and phenyl. Examples of additions across the double bond 9(10)R, include

William Rosenblatt; Lloyd I. Osipow; Foster Dee Snell

1966-01-01

207

40 CFR 721.9740 - Brominated triazine derivative.  

Code of Federal Regulations, 2013 CFR

...triazine derivative. (a) Chemical substance and significant...to reporting. (1) The chemical substance identified generically...requirements do not apply when the chemical substance is present in a plastic...elastomer, rubber matrix, or in solution. (iii) Industrial,...

2013-07-01

208

LLNL Chemical Kinetics Modeling Group  

SciTech Connect

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.

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

2008-09-24

209

Crosslinkable cellulose derivatives  

SciTech Connect

This paper reports method of treating a subterranean formation. It comprises: preparing a treating fluid composition with or without a particulate agent by admixing: an aqueous liquid, a cellulose ether derivative that is chemically modified by reacting the cellulose ether derivative with a vinyl phosphonic acid in the presence of the reaction product of hydrogen peroxide and a ferrous salt and a crosslinking agent; and injecting the treating fluid composition into the subterranean formation through a wellbore; injecting the treating fluid composition into the subterranean formation through a wellbore.

Holtmyer, M.; Hunt, C.V.

1991-11-26

210

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

Code of Federal Regulations, 2010 CFR

...2009-07-01 2009-07-01 false Phosphoric acid derivative (generic name...Chemical Substances § 721.6097 Phosphoric acid derivative (generic name...substance identified generically as a phosphoric acid derivative (PMN...

2009-07-01

211

Induction of CYP1A1, CYP1A2, and CYP1B1 mRNAs by nitropolycyclic aromatic hydrocarbons in various human tissue-derived cells: chemical-, cytochrome P450 isoform-, and cell-specific differences.  

PubMed

Nitropolycyclic aromatic hydrocarbons (NPAHs) are found in diesel exhaust and ambient air. NPAHs as well as polycyclic aromatic hydrocarbons (PAHs) are known to have mutagenicity, carcinogenicity, and endocrine-disruptive effects. In the present study, the inducibility of the human cytochrome P450-1 (CYP1) family by NPAHs was compared with those produced by their parent PAHs and some reductive metabolites, amino-PAHs. Furthermore, to investigate the differences in the inducibility of the CYP1 family in human tissues, various human tissue-derived cell lines, namely HepG2 (hepatocellular carcinoma), ACHN (renal carcinoma), A549 (lung carcinoma), MCF-7 (breast carcinoma), LS-180 (colon carcinoma), HT-1197 (bladder carcinoma), HeLa (cervix of uterus adenocarcinoma), OMC-3 (ovarian carcinoma), and NEC14 (testis embryonal carcinoma), were treated with NPAHs, PAHs, or amino-PAHs. The mRNA levels of CYP1A1, CYP1A2, and CYP1B1 were determined with reverse transcription-polymerase chain reaction (RT-PCR). The cell lines were classified into two groups: CYP1 inducible cell lines, comprising HepG2, MCF-7, LS-180, and OMC-3 cells, and CYP1 non-inducible cell lines, comprising ACHN, A549, HT-1197, HeLa, and NEC14 cells. In inducible cell lines, the induction profile of chemical specificity was similar for CYP1A1, CYP1A2, and CYP1B1, although the extent of induction differed among the cell lines and for the CYP isoforms. Pyrene, 1-nitropyrene, 1-aminopyrene, 1,3-, 1,6-, and 1,8-dinitropyrenes slightly induced CYP1 mRNAs, but 1,3-dinitropyrene produced a 6-fold induction of CYP1A1 mRNA in MCF-7 cells. 2-Nitrofluoranthene and 3-nitrofluoranthene exhibited stronger inducibility than fluoranthene in the inducible cell lines. 6-Nitrochrysene induced CYP1 mRNAs to the same extent or more potently than chrysene. The induction potencies of 6-nitrobenzo[ a]pyrene and 7-nitrobenz[ a]anthracene were weaker than those of their parents benzo[ a]pyrene and benz[ a]anthracene, respectively. This study demonstrated that NPAHs as well as PAHs induced human CYP1A1, CYP1A2, and CYP1B1 in a chemical-, CYP isoform-, and cell-specific manner. Furthermore, the cell-specific induction of the CYP1 family was not related to the expression levels of aryl hydrocarbon receptor, aryl hydrocarbon nuclear translocator, or estrogen receptors alpha and beta. PMID:12107646

Iwanari, Masashi; Nakajima, Miki; Kizu, Ryoichi; Hayakawa, Kazuichi; Yokoi, Tsuyoshi

2002-04-10

212

Betulinol derivatives  

US Patent & Trademark Office Database

The present invention is directed to betulinol derivatives and betulinol-antibody conjugates having the formulae: ##STR1## and and, in particular, betulinol dimethyl ether. Methods for making and using these derivatives and conjugates, as well as a method for making and using betulonic aldehyde, are also disclosed.

Bomshteyn; Arkadiy L. (Brooklyn, NY); Rathnam; Premila (Englewood Cliffs, NJ); Saxena; Brij B. (Englewood, NJ)

2005-05-10

213

Biomass, Chemicals from  

SciTech Connect

This chapter describes the use and potential use of biomass resources for chemical production as a means to displace petroleum use. Therefore, the scope of the discussion is limited to large scale, commodity chemical products that can have an impact on the energy market by displacing petroleum conversion to chemical products. This article does not address in detail specialty chemical products whose limited market would have minimal impact on energy markets; nor does it describe in detail the use of biomass for material products such as cellulosic fiber for paper or lignocellulosic material for construction materials. The use of biomass for production of a vast array of specialty chemicals based on unique biochemical structures is another part of the overall concept of a sustainable economy, but is outside the scope of this article. Chemical production from biomass is an energy issue in that biomass-derived chemicals can result in a significant impact on the petroleum requirement for petrochemicals used in modern society. Petroleum thus displaced is available for use in the energy market. Petroleum utilization for chemicals production is reported at 14% of the petroleum market in the United States. Displacement of a significant fraction of this chemical synthesis from petroleum can provide an important impact on the overall market. In 1998 the U.S. Department of Energy stated as its goal the production of at least 10% of the basic chemical building blocks from plant-derived renewables by the year 2020 (a five-fold increase) and 50% by 2050 (another five-fold increase). In the long run, utilization of renewable carbon sources for the chemical requirements of society is the only option as fossil sources become more scarce.

Elliott, Douglas C.

2004-03-15

214

Crosslinkable cellulose derivatives  

SciTech Connect

This patent describes a method for treating a subterranean formation. It comprises: preparing a treating fluid composition with or without a particulate agent by admixing an aqueous liquid, a cellulose ether derivative consisting essentially of the reaction product of a cellulose ether with a ceric salt, the reaction occurring under acidic conditions and at a temperature in the range of from about 20{degree} to about 60{degree}C. and a cross-linking agent; and injecting the treating fluid composition into the subterranean formation through a wellbore. This patent also describes a method of treating a subterranean formation. It comprises: preparing a treating fluid composition with or without a particulate agent by admixing an aqueous liquid, a cellulose ether derivative that is chemically modified by reacting under acidic conditions the cellulose ether derivative with a vinyl phosphonic acid and a ceric salt, and a crosslinking agent; and injecting the treating fluid composition into the subterranean formation through a wellbore.

Holtmeyer, M.D.; Hunt, C.V.; Harms, W.M.

1991-01-08

215

Semisynthetic Derivatives of Epothilones  

NASA Astrophysics Data System (ADS)

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.

Altmann, Karl-Heinz

216

Maximum work from isothermal chemical engines  

NASA Astrophysics Data System (ADS)

Upper bounds are derived for the work that can be extracted from simple isothermal chemical converters (chemical engines) that operate from a finite chemical potential reservoir. The incremental gains that stem from adding an arbitrary number of engines is derived. Results are analogous to those for heat engines fed by a finite heat capacity reservoir. Systems of practical interest include chemical reactions, electrochemical cells, and solid-state converters. The effectiveness of introducing more engines to utilize unexploited chemical potential is expressed in terms of the specific relation between mass transfer and chemical potential difference, often referred to as the device's current-voltage curve.

Gordon, J. M.

1993-01-01

217

Complex derivatives  

NASA Astrophysics Data System (ADS)

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

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

2013-03-01

218

Chemical Biology\\/ Chemical Genetics\\/ Chemical Genomics: Importance of Chemical Library  

Microsoft Academic Search

A new field of science, chemical biology\\/ chemical genetics\\/ chemical genomics (cb\\/cg\\/cg) has emerged since the late 1990's, especially in the United States. The NIH Roadmap agenda, Molecular Libraries Screening Center Network (MLSCN), became a drive force to push cb\\/cg\\/cg forward. Cb\\/cg\\/cg studies consist of three methodologies, chemical libraries with small molecules, high-throughput screenings, and computational databases. In this review,

Fumihiko Kugawa; Masaru Watanabe; Fuyuhiko Tamanoi

2007-01-01

219

40 CFR 721.10317 - Alkyl phosphate derivative (generic).  

Code of Federal Regulations, 2013 CFR

...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)...

2013-07-01

220

Leaching Properties and Chemical Compositions of Calcines Produced at the Idaho Chemical Processing Plant.  

National Technical Information Service (NTIS)

No significant chemical differences were determined between retrieved and fresh calcine based on chemical and spectrochemical analyses. Little can be derived from the amounts of the radioisotopes present in the retrieved calcine samples other than the rat...

B. A. Staples B. E. Paige D. W. Rhodes M. W. Wilding

1980-01-01

221

Dimeric avermectin and milbemycin derivatives  

US Patent & Trademark Office Database

This invention provides for novel antiparasitic and pesticidal derivatives of avermectin and milbemycin compounds in which two avermectin or milbemycin members are linked together by a chemical linker. The resulting compounds may be used in veterinary compositions which are used in treating, controlling and preventing of endo- and ectoparasite infections and infestations in animals or for combating pests in plants or plant propagation material.

Meng; Charles Q. (Johns Creek, GA)

2013-04-23

222

Chemical modification of chitin and chitosan 1: preparation of partially deacetylated chitin derivatives via a ring-opening reaction with cyclic acid anhydrides in lithium chloride\\/ N, N-dimethylacetamide  

Microsoft Academic Search

Derivatives of partially N-deacetylated chitin (DAC) were prepared via ring-opening reactions with various cyclic acid anhydrides in lithium chloride\\/N,N-dimethylacetamide (LiCl\\/DMAc) system. Some cyclic acid anhydrides such as succinic, maleic, glutaric, and phthalic anhydrides gave successfully water-soluble DAC derivatives. From the enzymatic studies, the glycosyl bond of succinyl and maleoyl DAC-20 (20% DAC) was rapidly degraded by lysozyme or chitinase, though

Y Shigemasa; H Usui; M Morimoto; H Saimoto; Y Okamoto; S Minami; H Sashiwa

1999-01-01

223

[Chemical weapons and chemical terrorism].  

PubMed

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

Nakamura, Katsumi

2005-10-01

224

Chemical Bonds  

NSDL National Science Digital Library

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

Consortium, The C.

2011-12-11

225

Dynamic light scattering investigations of a new class of polyethyleneimine derivatives.  

National Technical Information Service (NTIS)

Dynamic light scattering measurements were performed on polyethyleneimine and several chemically modified derivatives that differ in site, degree of substitution, and chemical nature of alkyl substituents. Moreover, two of the six polymer derivatives were...

D. M. Budzynski A. S. Benight E. A. Myatt

1992-01-01

226

Chemical agents and chemical terrorism.  

PubMed

Chemical terrorism is a new threat to the security of mankind, which scale essentially exceeds the impact of use of the most modem firearms. At present time all over the world threats from different radical elements to use radioactive materials, potent poisonous substances and pathogenic microorganisms for terrorist purposes became more frequent. High-toxic chemical substances can fall in terrorist hands through wide range of sources. Potentially misused types of chemical compounds are discussed in this article. PMID:15141987

Patocka, J; Fusek, J

2004-03-01

227

Chemical Reactions  

NSDL National Science Digital Library

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

National Science Teachers Association (NSTA)

2009-05-01

228

Chemical spectroscopy  

Microsoft Academic Search

The purpose of chemical spectroscopy with neutrons is to utilize the dependence of neutron scattering cross sections on isotope and on momentum transfer (which probes the spatial extent of the excitation) to understand fundamental and applied aspects of the dynamics of molecules and fluids. Chemical spectroscopy is divided into three energy ranges: vibrational spectroscopy, 25-500 MeV, for which much of

J. Eckert; T. O. Brun; A. J. Dianoux; J. Howard; J. J. Rush; J. W. White

1984-01-01

229

Chemical sensors  

DOEpatents

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.

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

1991-07-02

230

Chemical Composition  

Microsoft Academic Search

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

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

2006-01-01

231

Chemical Name  

Cancer.gov

Attachment III Chemical Quick Reference Chart for Minors Chemical Name Select Carcinogen Reproductive Toxin LD50 < 50 mg/kg (oral rat) LD50 < 200 mg/kg for 24 hours or less (dermal rabbit) LC50 < 200 ppm or 2 mg/L for one hour (inhalation rat)

232

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)

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

Allen, Mark Ryan

233

Chemical threats.  

PubMed

The use of chemical agents as military weapons has been recognized for many centuries but reached the most feared and publicized level during World War I. Considerable political effort has been exercised in the twentieth century to restrict military strategies with chemicals. However, considerable concern currently exists that chemical weapons may be used as agents in civilian terrorism. The distribution of acetaminophen tablets contaminated with potassium cyanide and the release of sarin in the Tokyo sub-way system show that larger-scale deployment of chemical agents can be a reality. This reality makes it necessary for civilian disaster-planning strategies to incorporate an understanding of chemical agents, their effects, and the necessary treatment. PMID:16781273

Fry, Donald E

2006-06-01

234

Enhanced detectability of fluorinated derivatives of N, N-dialkylamino alcohols and precursors of nitrogen mustards by gas chromatography coupled to Fourier transform infrared spectroscopy analysis for verification of chemical weapons convention  

Microsoft Academic Search

N,N-Dialkylamino alcohols, N-methyldiethanolamine, N-ethyldiethanolamine and triethanolamine are the precursors of VX type nerve agents and three different nitrogen mustards respectively. Their detection and identification is of paramount importance for verification analysis of chemical weapons convention. GC–FTIR is used as complimentary technique to GC–MS analysis for identification of these analytes. One constraint of GC–FTIR, its low sensitivity, was overcome by converting

Prabhat Garg; Ajay Purohit; Vijay K. Tak; D. K. Dubey

2009-01-01

235

Chemical and Physical Properties of Tetracyclo-(3.3.O.O(2,8).O(4,8)) Octane and Tetracyclo(3.3.1.O(2,8).O(4,6))-Nonane Derivatives.  

National Technical Information Service (NTIS)

The compounds 3-tetracyclo(3.3.0.0.(2,8).0(4,6))octane, 3-tetracyclo(3.3.1.0.(2,8).0(4,6))nonane, 8-bicyclo(3.2.1)oct-2-ene, 8-bicyclo(3.3.0)oct-2-ene, 3-tricyclo(3.3.0.0(2,8))octane and 3-bicyclo(3.2.1)oct-6-ene were examined. In addition, the chemical a...

N. A. LeBel

1970-01-01

236

Chemical Aspects of Organotin Derivatives of Beta?diketones, Quinonoids, Steroids and Some Currently Used Drugs: A Review of the Literature with Emphasis on the Medicinal Potential of Organotins  

Microsoft Academic Search

The last 50–70 years there has been an increasing interest on organotin compounds mainly because of their industrial, agricultural and biological applications. This review aims to offer a substantial overview of the organotin complexes of beta?diketones and beta?diketone derivatives, quinonoids, steroids and NSAIDs describing their structure, coordination mode and properties. Discussion will be focused on the interaction of organotins with

Vasiliki Valla

2007-01-01

237

Chemical Agents  

Center for Drug Evaluation (CDER)

... FDA has cleared for use by the US military a liquid decontamination lotion intended to remove or neutralize chemical warfare agents and T-2 fungal ... More results from www.fda.gov/drugs/emergencypreparedness/bioterrorismanddrugpreparedness

238

Unnecessary Chemicals  

ERIC Educational Resources Information Center

|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)|

Johnson, Anita

1978-01-01

239

Unnecessary Chemicals  

ERIC Educational Resources Information Center

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)

Johnson, Anita

1978-01-01

240

Chemical Emergency  

MedlinePLUS

... Prepare Your Workplace Types of Emergency Chemical Emergency Drought Preparedness Earthquake Home Fire Flood Flu Food Safety ... you have been advised by medical professionals. Next Drought Preparedness & Water Conservation Be Red Cross Ready Are ...

241

Chemical Kinetics  

Microsoft Academic Search

\\u000a While thermodynamics provides steady-state information of the combustion process, chemical kinetics describes the transient\\u000a states of the system during the combustion process. Particularly important is information related to the rate at which species\\u000a are consumed and produced, and the rate at which the heat is released. Combustion chemistry has two important characteristics\\u000a not commonly observed in other chemical systems. First,

Sara McAllister; Jyh-Yuan Chen; A. Carlos Fernandez-Pello

242

The studies of tautomerism in 6-mercaptopurine derivatives by 1H 13C, 1H 15N NMR and 13C, 15N CPMAS-experimental and quantum chemical approach  

NASA Astrophysics Data System (ADS)

Tautomerism in 6-mercaptopurine (6mpH), 2,6-dimercaptopurine (2,6dmp) and 6-mercaptopurine-9-riboside (6mp-9rb) was studied in the solution with 2D NMR methods-1H 13C HMBC and 1H 15N HMQC. The 15N NMR signals were assigned and the distribution of mobile protons proposed on the basis of ?13C, ?15N chemical shifts and JHC, JHN coupling constants, determined with HECADE. These heterocycles appear in DMSO-d6 as the thionic species with predominance of the following tautomers: N(1)H, N(7)H for 6mpH; N(1)H, N(3)H, N(7)H for 2,6dmp; N(1)H for 6mp-9rb. Quantum-chemical NMR calculations by GIAO method(RHF/6-31G**//B3LYP/6-31G**) allowed to evaluate the ratios of N(7)H, N(9): N(7), N(9)H tautomeric forms as ca. 3:1 for 6mpH and nearly 10:0 for 2,6dmp. The 13C and 15N CPMAS spectra were measured for solid 6mpH·H2O, anhydrous 6mpH, 2,6dmp and 6-mercaptopurinium chloride (6mpH2Cl), confirming the thionic character of all compounds. The 15N chemical shifts in the solid phase were calculated (B3LYP/6 31G**) for 6mpH·H2O and 6mpH2Cl, basing on the re-determined single crystal X-ray data (optimised with RHF/3-21G**).

Pazderski, Leszek; ?akomska, Iwona; Wojtczak, Andrzej; Sz?yk, Edward; Sitkowski, Jerzy; Kozerski, Lech; Kamie?ski, Bohdan; Ko?mi?ski, Wiktor; Tousek, Jaromír; Marek, Radek

2006-03-01

243

40 CFR 721.10147 - Acrylate derivative of alkoxysilylalkane ester and mixed metal oxides (generic).  

Code of Federal Regulations, 2013 CFR

...derivative of alkoxysilylalkane ester and mixed metal oxides (generic). 721.10147 Section...derivative of alkoxysilylalkane ester and mixed metal oxides (generic). (a) Chemical...derivative of alkoxysilylalkane ester and mixed metal oxides (PMN P-07-198) is...

2013-07-01

244

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

Code of Federal Regulations, 2010 CFR

...false Benzene, (2-bromoethyl)-, ar-bromo derivatives. 721.1240 Section...1240 Benzene, (2-bromoethyl)-, ar-bromo derivatives. (a) Chemical...identified as benzene, (2-bromoethyl)-, ar-bromo derivatives (PMN...

2009-07-01

245

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

Code of Federal Regulations, 2010 CFR

...false Benzene, (2-bromoethyl)-, ar-bromo derivatives. 721.1240 Section...1240 Benzene, (2-bromoethyl)-, ar-bromo derivatives. (a) Chemical...identified as benzene, (2-bromoethyl)-, ar-bromo derivatives (PMN...

2010-07-01

246

Chemical Warfare and Chemical Disarmament.  

ERIC Educational Resources Information Center

|Described are some of the technical, military, and political considerations that bear most directly on the choices facing the United States and its NATO allies on modern lethal chemical weapons. (BT)|

Meselson, Matthew; Robinson, Julian Perry

1980-01-01

247

Phase stabilities of monoclinic oxoborates LaB3O6 and GdB3O6 in C121 and I12/a1 phase—Energetics and chemical bonds derived from first-principles calculations  

NASA Astrophysics Data System (ADS)

The computational study on the relative phase stabilities between two monoclinic polymorphs of the lanthanide-containing oxoborates LaB3O6 and GdB3O6 is presented at the first-principles density functional theory gradient-corrected B3PW level. The hypothetical monoclinic ?-BiB3O6-like C121 non-centrosymmetric crystal structures were assumed for LaB3O6 and GdB3O6 and the corresponding geometries were calculated and compared with their monoclinic I12/a1 centrosymmetric structures. The enthalpy pressure correlations were calculated and the first-principles chemical bonds based on the crystal orbital overlapping population were quantitatively analyzed for LaB3O6 and GdB3O6. The chemical bonds between the central cation (La (III)/Gd (III)) and coordinated oxygen atoms rather than the B O bonds in the borate units are found to stabilize the I12/a1 centrosymmetric LaB3O6 and GdB3O6 structures with respect to the C121 non-centrosymmetric counterparts.

Yang, Jun; Dolg, Michael

2007-10-01

248

Chemical sensors  

SciTech Connect

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.

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

1987-05-01

249

Kinetic theory of steady chemical nucleation in the gas phase  

Microsoft Academic Search

We develop a kinetic theory of nucleation involving chemical reactions in the gas phase. For the basis of deriving the chemical nucleation rate, chemical kinetic considerations are presented on the steady current density and the effective rate constants of the overall reaction, which is a sum of a sequential elementary reactions. We formulate the steady rate of chemical nucleation in

T. Yamamoto; T. Chigai; S. Watanabe; T. Kozasa

2001-01-01

250

Structural, ferroelectric, dielectric, and magnetic properties of BiFeO3/Pb(Zr0.5,Ti0.5)O3 multilayer films derived by chemical solution deposition  

NASA Astrophysics Data System (ADS)

BiFeO3/Pb(Zr0.5,Ti0.5)O3 (BFO/PZT) multilayer films have been grown on platinum-coated silicon substrate by chemical solution deposition. The remnant polarization is about 12 ?C/cm2, which is much bigger than most of pure BFO thin films. P-E measurement shows that there are more obstacles affecting the motion of the domain wall in the multilayer films than those in the pure PZT films. This conclusion is also confirmed by measuring the dependence of capacitance with ac field under subswitching field. The frequency dependence of dielectric loss indicates that the dielectric loss (tan ?) of the multilayer is smaller than that of the PZT thin films at high frequency. Magnetic measurement indicates that the multilayer films are antiferromagnetic.

Li, Y. W.; Sun, J. L.; Chen, J.; Meng, X. J.; Chu, J. H.

2005-10-01

251

Chemical Modification of Polysaccharides  

PubMed Central

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.

Cumpstey, Ian

2013-01-01

252

Sound Absorption in Dilute Chemically Reacting Systems.  

National Technical Information Service (NTIS)

A systematic theoretical development is presented for sound absorption in dilute chemically reacting systems when heat effects and other dissipative mechanisms, e.g. diffusion and viscous damping, are ignored. A derivation is presented for the isothermal ...

J. M. Deuth

1981-01-01

253

Chemical defense by termite soldiers  

Microsoft Academic Search

The chemistry of the defensive secretions of termite soldiers is reviewed. The structural variety of the chemical weapons, the uses of these substances in defense, and some potential biosynthetic interrelationships are discussed. Classification of the monoterpenes, sesquiterpenes, diterpenes, and various acetate-derived compounds according to termite subfamilies places the known defense substances in a phylogenetic perspective.

Glenn D. Prestwich

1979-01-01

254

Chemical sensors  

SciTech Connect

This review of chemical sensors contains the following topics of interest: books and reviews; reviews of sensors by their type; fabrication and selectivity; data processing; thermal sensors; mass sensors (fabrication, gas sensors, and liquid sensors); electrochemical sensors (potentiometric sensors, amperometric sensors, and conductometric sensors); and optical sensors (fabrication, liquid sensors, biosensors, and gas sensors). 795 refs., 1 tab.

Janata, J.; Josowicz, M.; DeVaney, D.M. (Pacific Northwest Lab., Richland, WA (United States))

1994-06-15

255

Delicious Chemicals.  

ERIC Educational Resources Information Center

|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…

Barry, Dana M.

256

Chemical Ionization  

Microsoft Academic Search

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

Jürgen H. Gross; Mass Spectrometry

257

Chemical Mahjong  

ERIC Educational Resources Information Center

|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…

Cossairt, Travis J.; Grubbs, W. Tandy

2011-01-01

258

Chemical Indicators.  

ERIC Educational Resources Information Center

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

Prombain, Dorothy R.; And Others

259

Four new citrinin derivatives from a marine-derived Penicillium sp. fungal strain.  

PubMed

Four new citrinin derivatives, including two citrinin dimers and two citrinin monomer derivatives, were isolated and identified from a marine-derived fungal strain Penicillium sp. ML226 along with six known related compounds. Their structures were elucidated by spectroscopic and chemical methods. The new compounds showed modest cytotoxic activity against HepG-2 cell line and weak antimicrobial activity against Staphylococcus aureus. PMID:23681057

Wang, Mei Ling; Lu, Chun Hua; Xu, Qing Yan; Song, Si Yang; Hu, Zhi Yu; Zheng, Zhong Hui

2013-05-16

260

Stimulation with a monoclonal antibody (mAb4E4) of scavenger receptor-mediated uptake of chemically modified low density lipoproteins by THP-1-derived macrophages enhances foam cell generation.  

PubMed Central

mAb4E4, a murine monoclonal antibody that is specific for acetylated LDL and malondialdehyde-treated LDL, binds specifically to modified LDL present in human atherosclerotic lesions. It is directed against an epitope that is poorly exposed in delipidated and solubilized apolipoprotein B-100 from modified LDL. mAb4E4, as well as its F(ab')2 and Fab fragments, enhanced the uptake of both acetylated LDL and malondialdehyde-treated LDL by THP-1-derived macrophages resulting in a sixfold increase of cytoplasmic cholesteryl ester levels. The increased uptake of modified LDL/mAb4E4 complexes did not occur via the Fc receptor and did not depend on aggregation of modified LDL particles. However, their uptake was inhibited by blocking the scavenger receptors with fucoidin or by downregulation of receptor expression with endotoxins or interferon-gamma, indicating that their uptake is mediated via these receptors. Thus, generation of autoimmune antibodies against modified LDL and subsequent endocytosis of soluble modified LDL/antibody complexes via scavenger receptors may enhance foam cell generation. This mechanism may contribute to the progression of atherosclerotic lesions. Images

Holvoet, P; Perez, G; Bernar, H; Brouwers, E; Vanloo, B; Rosseneu, M; Collen, D

1994-01-01

261

Automated large-scale culture and medium-throughput chemical screen for modulators of proliferation and viability of human induced pluripotent stem cell-derived neuroepithelial-like stem cells.  

PubMed

The aim of this study was to demonstrate proof-of-concept feasibility for the use of human neural stem cells (NSCs) for high-throughput screening (HTS) applications. For this study, an adherent human induced pluripotent stem (iPS) cell-derived long-term, self-renewing, neuroepithelial-like stem (lt-NES) cell line was selected as a representative NSC. Here, we describe the automated large-scale serum-free culture ("scale-up") of human lt-NES cells on the CompacT SelecT cell culture robotic platform, followed by their subsequent automated "scale-out" into a microwell plate format. We also report a medium-throughput screen of 1000 compounds to identify modulators of neural stem cell proliferation and/or survival. The screen was performed on two independent occasions using a cell viability assay with end-point reading resulting in the identification of 24 potential hit compounds, 5 of which were found to increase the proliferation and/or survival of human lt-NES on both occasions. Follow-up studies confirmed a dose-dependent effect of one of the hit compounds, which was a Cdk-2 modulator. This approach could be further developed as part of a strategy to screen compounds to either improve the procedures for the in vitro expansion of neural stem cells or to potentially modulate endogenous neural stem cell behavior in the diseased nervous system. PMID:23042076

McLaren, Donna; Gorba, Thorsten; Marguerie de Rotrou, Anita; Pillai, Gopalan; Chappell, Clare; Stacey, Alison; Lingard, Sarah; Falk, Anna; Smith, Austin; Koch, Philipp; Brüstle, Oliver; Vickers, Richard; Tinsley, Jon; Flanders, David; Bello, Paul; Craig, Stewart

2012-10-04

262

Chemical methods for the production of graphenes  

Microsoft Academic Search

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

Sungjin Park; Rodney S. Ruoff

2009-01-01

263

Chemicals from coal: ERDA's programs and plans  

Microsoft Academic Search

ERDA's current and planned programs have the objective of evaluating the potential of producing chemicals from coal, coal liquids, and from synthesis gas derived from coal. The Dow Chemical program is aimed at estimating preliminary capital investment and operating costs for a commercial plant which would utilize coal liquefaction products for the production of useful aliphatic and aromatic compounds. Laboratory

Harney

1976-01-01

264

Inactivation of coliphages by chitosan derivatives  

Microsoft Academic Search

The effect of chitosan fragments with different degrees of polymerization and the chemical derivatives of chitosan differing\\u000a in the number of amino groups and total molecule charge on phages T2, T4, and T7 was studied. The interaction of chitosan\\u000a with bacteriophage particles inactivated them to the extent dependent on the chemical properties of chitosan and its concentration.\\u000a Phage T2 was

Z. M. Kochkina; N. A. Surgucheva; S. N. Chirkov

2000-01-01

265

Stabilization of biomass-derived pyrolysis oils  

Microsoft Academic Search

BACKGROUND:Biomassistheonlyrenewablefeedstockcontainingcarbon,andthereforetheonlyalternativetofossil-derived crude oil derivatives. However, the main problems concerning the application of biomass for biofuels and bio-based chemicals are related to transport and handling, the limited scale of the conversion process and the competition with the food industry. Toovercome suchproblems,anintegralprocessing routefortheconversionof(non-feed)biomass(residues)totransportation fuels is proposed. It includes a pretreatment process by fast pyrolysis, followed by upgrading to produce a crude-oil-like product,

A. Oasmaa; J. Wildschut; A. R. Ardiyanti; R. H. Venderbosch; H. J. Heeres

2010-01-01

266

Chemical Separations  

NSDL National Science Digital Library

This site contains complete notes in a PowerPoint-like presentation for a chemical separations course. It covers a wide variety of topics, including distillation, extraction, gas chromatography, liquid chromatograpy, chromatography theory, instrumentation, electrophoresis, field flow fractionation, and affinity chromatography. It covers these topics thoroughly using a clear, consistent, and simple presentation style. Links to major topics like GC, LC, and electrophoresis provide specific information about the theory, instrumentation, and practice related to these techniques. The site also contains many annimations illustrating important separation processes.

2011-05-18

267

Chemical lasers  

NASA Astrophysics Data System (ADS)

The application and the advances of quantum electronics, specifically, of optical quantum generators lasers is reviewed. Materials are cut, their surfaces are machined, chemical transformations of substances are carried out, surgical operations are performed, data are transmitted, three dimensional images are produced and the content of microimpurities, in the atmosphere, are analyzed by use of a beam. Laser technology is used in conducting investigations in the most diverse fields of the natural and technical sciences from controlled thermonuclear fusion to genetics. Many demands are placed on lasers as sources of light energy. The importance of low weight, compactness of the optical generator and the efficiency of energy conversion processes is emphasized.

Khariton, Y.

1984-08-01

268

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

Code of Federal Regulations, 2013 CFR

...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...

2013-07-01

269

Plant-derived wildlife repellents  

US Patent & Trademark Office Database

Products from the plant species Nerium oleander and, Urginea maritima, are prepared and tested as wildlife repellents comparing them with digitalis products. Chemical compounds derived from these plants including oleandrin, oleandrigenin, scillirosidin, digitoxigenin and digoxigenin are shown to cause nausea and emesis at low doses in pigeons and to repel, mice, rats, gophers, meadow voles and mountain beavers. After ingestion these animals quickly learn to avoid targets treated with the plant-derived repellents. When the remembrance of a treated food or other target lasts for an extended period of time it can be termed an aversion conditioning agent. Such products can be used for the protection of other plants, seeds, buildings, structures, communication cables and animals exposed to wildlife.

Verbiscar; Anthony J. (Sierra Madre, CA)

1994-10-18

270

[Research progress of chromanone derivatives from Calophyllum].  

PubMed

Calophyllum plants have great pharmaceutical value. Some species of this genus are used in folk medicine to treat and cure diseases, such as toothache, rheumatism, diarrhea, chronic ulcers, skin infections, and wounds. The genus is known to be rich in chromanone derivatives, and some of these compounds have antiviral, antifungal, antibacterial, cytotoxic, and other activities. In order to come to a more complete understanding of chromanone derivatives and gain new bioactive constituents from Calophyllum, chemical structures, pharmacological activities, and biogenesis of chromanone derivatives from Calophyllum have been discussed in this review. PMID:21842632

Wang, Huan; Wang, Yuehu; Li, Juan; Chen, Lijuan

2011-05-01

271

Weather Derivative Valuation  

NASA Astrophysics Data System (ADS)

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.

Jewson, Stephen; Brix, Anders

2005-04-01

272

Environmental risk assessment of existing chemicals  

Microsoft Academic Search

Most of the existing chemicals of high priority have been released into the environment for many years. Risk assessments for\\u000a existing chemicals are now conducted within the framework of the German Existing Chemicals Program and by the EC Regulation\\u000a on Existing Substances. The environmental assessment of a chemical involves:\\u000a \\u000a \\u000a a) \\u000a \\u000a exposure assessment leading to the derivation of a predicted environmental

Jan Ahlers; Robert Diderich; Ursula Klaschka; Annette Marschner; Beatrice Schwarz-Schulz

1994-01-01

273

Chemicals from corn: much more than ethanol  

SciTech Connect

A leading U.S. chemical company, A.E. Staley, Decatur, Ill., came onstream towards the end of 1981 with a pilot plant designed to produce methyl glucoside by fermentation from corn starch about half the cost of using conventional synthesis from hydrocarbons. The company aims ultimately to produce a line of corn-derived organic chemicals. Another company, CPC International, N.J., is selling corn raw materials - corn starch, corn syrup, dextrose - to chemical companies and then working with them to produce specific organic chemicals.

Not Available

1982-02-24

274

Synthesis and absorption spectra of thienylphenylpropenol derivatives  

Microsoft Academic Search

Fourteen thienylphenylpropenol derivatives containing substituents of varying electronic nature were synthesized. IR and NMR spectroscopy established that the a, ß-unsaturated alcohols obtained belong to the trans series. The electronic and PMR spectra of the alcohols in neutral and acidic solutions were studied. A correlation was found between the chemical shifts of the proton of the alcohol hydroxyl group and the

V. F. Lavrushin; R. I. Pogonina; N. S. Pivnenko; V. P. Izvekov

1970-01-01

275

Chemiluminescence of indole and its derivatives  

NASA Astrophysics Data System (ADS)

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.

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

2010-02-01

276

Prediction for biodegradability of chemicals by an empirical flowchart  

Microsoft Academic Search

A method for predicting aerobic biodegradability of chemicals was developed based on empirical knowledge. A flowchart was derived from rule of thumb relationships between the biodegradability and the number of the functional groups and substructures in a certain skeletal structure of chemicals. The flowchart classified chemicals into readily biodegradable, not readily biodegradable and not predictable. It was validated by using

Koichi Hiromatsu; Yoshikuni Yakabe; Kazuomi Katagiri; Tsutomu Nishihara

2000-01-01

277

Carbon Nano Tube Composites with Chemically Functionalized Plant Oils  

Microsoft Academic Search

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

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

2003-01-01

278

Chemical Potential from the Beginning  

Microsoft Academic Search

The chemical potential ?, commonly defined as a partial derivative of a quantity which involves energy and entropy, is often\\u000a regarded as difficult to grasp not only by students. As a fast and easy way, without frightening mathematics, it is suggested\\u000a to introduce this quantity by a phenomenological definition and direct measuring procedure, a method usual for various basic\\u000a quantities

R. Rüffler; G. Job

279

CHEMICAL PACEMAKERS  

PubMed Central

1. Iron spicules found in the brains of general paretic patients are formed from endogenous brain iron normally present in another form. This supports our earlier view that the µ value of 16,000 obtained in advanced paretics for alpha brain wave frequencies as a measure of cortical respiration comes about from the slowing of an iron catalyzed link in cortical respiration such as would result from the reduction of available cytochrome and its oxidase, thus making this step a chemical pacemaker. 2. To test the basic theory of chemical pacemakers, a study was made of the succinate-fumarate enzyme system containing succino-dehydrogenase and cytochrome-cytochrome oxidase acting sequentially. 3. The µ value for the unpoisoned system is 11,200 ± 200 calories. 4. According to theory, the addition of a critical amount of cyanide known to be a specific poison of the cytochrome-cytochrome oxidase system (and not of the dehydrogenase) should shift the µ cleanly to 16,000 calories, and it does. 5. According to theory, selenite, a specific poison for the dehydrogenase, should stop all respiration without shifting the µ. This also is found to be the case. 6. The theory also predicts that if the µ is shifted from 11,000 ± to 16,000 ± by cyanide, the subsequent addition of a critical amount of selenite should shift the µ back again to 11,000 ± calories, and this is found to occur. 7. It is concluded that approximately 11,000 calories is the energy of activation of the succino-dehydrogenase-catalyzed step and 16,000 calories is that for the cytochrome-cytochrome oxidase-catalyzed step. These two values are encountered more frequently than any others in physiological systems. It is to be recalled that a shift of µ for alpha brain wave frequencies from 11,000 to 16,000 calories occurs in the course of advancing syphilitic brain infection and is accompanied by a change in form of brain iron.

Hadidian, Zareh; Hoagland, Hudson

1939-01-01

280

ASSESSING BIOACCUMULATION FOR DERIVING NATIONAL HUMAN HEALTH WATER QUALITY CRITERIA  

EPA Science Inventory

The United States Environmental Protection Agency is revising its methodology for deriving national ambient water quality criteria (AWQC) to protect human health. A component of this guidance involves assessing the potential for chemical bioaccumulation in commonly consumed fish ...

281

Synthesis of methyl methacrylate from coal-derived syngas.  

National Technical Information Service (NTIS)

Research Triangle Institute (RTI), Eastman Chemical Company, and Bechtel collectively are developing a novel three-step process for the synthesis of methyl methacrylate (MMA) from coal-derived syngas that consists of the steps of synthesis of a propionate...

B. W. L. Jang G. N. Choi J. J. Spivey J. R. Zoeller R. D. Colberg

1998-01-01

282

Synthesis of acrylates and Methacrylates from Coal-Derived Syngas.  

National Technical Information Service (NTIS)

Research Triangle Institute (RTI), Eastman Chemical Company, and Bechtel collectively are developing a novel process for the synthesis of methyl methacrylate (MMA) from coal-derived syngas, under a contract from the U.S. Department of Energy, Federal Ener...

1997-01-01

283

Sultamo-Steroid analogues, part VII: Synthesis of epiandrosterone derivatives with potential activity  

Microsoft Academic Search

The reaction of epi-androsterone with cyanoacetyl hydrazine (2) gave the hydrazone derivative3. The reactivity of3 towards chemical reagents was studied to give pyridine, thiazole and thiophene derivatives.

Senot H. Doss; Nadia A. Louca; Gamal A. Elmegeed; Rafat M. Mohareb

1999-01-01

284

Chemical composition of the Orion nebula derived from echelle spectrophotometry  

Microsoft Academic Search

We present echelle spectroscopy in the 3500- to 7060-Å range for two positions of the Orion nebula. The data were obtained using the 2.1-m telescope at Observatorio Astrónmico Nacional in San Pedro Mártir, Baja California. We have measured the intensities of about 220 emission lines, in particular 81 permitted lines of C+, N+, N++, 0°, 0+, Ne0, Si+, Si++ and

C. Esteban; M. Peimbert; S. Torres-Peimbert; V. Escalante

1998-01-01

285

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...

286

Chemical determination of unsaturation of fats and derivatives  

Microsoft Academic Search

be obtained from a new product are worth less than the cost of evaluating the surfactants. Nevertheless extensive surfactant testing is being carried out in many of the larger mills. Some of the factors which will cause further shifts in the selection of surfactants are: the steadily decreasing price of the nonionics, the increasing proportion of fabric that receives special

Don S. Bolley; James Egee; H. Ehrhardt; Botany Mills; J. M. Jester; E. A. Leonard; Joseph Oliver

1955-01-01

287

Renewable Chemicals: Dehydroxylation of Glycerol and Polyols  

PubMed Central

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.

ten Dam, Jeroen; Hanefeld, Ulf

2011-01-01

288

Utilization of lignins and lignin derivatives. Parts 1 and 2  

SciTech Connect

A total of 3742 abstracts, from the Abstract Bulletin of the Institute of Paper Chemistry and Chemical Abstracts, are presented of scientific articles and patents on the use of lignin and its derivatives in: adhesives, agricultural chemicals, water treatment, general applications, cement, drilling, rubber, dispersing agents, tanning, batteries, and miscellaneous applications. Author, subject and patent indexes are included.

Boyle, F.

1984-01-01

289

Chemical-potential route for multicomponent fluids.  

PubMed

The chemical potentials of multicomponent fluids are derived in terms of the pair correlation functions for arbitrary number of components, interaction potentials, and dimensionality. The formally exact result is particularized to hard-sphere mixtures with zero or positive nonadditivity. As a simple application, the chemical potentials of three-dimensional additive hard-sphere mixtures are derived from the Percus-Yevick theory and the associated equation of state is obtained. This Percus-Yevick chemical-route equation of state is shown to be more accurate than the virial equation of state. An interpolation between the chemical-potential and compressibility routes exhibits a better performance than the well-known Boublík-Mansoori-Carnahan-Starling-Leland equation of state. PMID:23767518

Santos, Andrés; Rohrmann, René D

2013-05-29

290

Chemical Ecology: Chemical Communication in Nature.  

ERIC Educational Resources Information Center

|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)|

Wood, William F.

1983-01-01

291

21 CFR 189.120 - Cobaltous salts and its derivatives.  

Code of Federal Regulations, 2013 CFR

...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 ,...

2013-04-01

292

Toxicity of Benzotriazole and Benzotriazole Derivatives to Three Aquatic Species  

Microsoft Academic Search

Benzotriazole and its derivatives comprise an important class of corrosion inhibitors, typically used as trace additives in industrial chemical mixtures such as coolants, deicers, surface coatings, cutting fluids, and hydraulic fluids. Recent studies have shown that benzotriazole derivatives are a major component of aircraft deicing fluids (ADFs) responsible for toxicity to bacteria (Microtox®). Our current research compared the toxicity of

David A Pillard; Jeffrey S Cornell; Doree L DuFresne; Mark T Hernandez

2001-01-01

293

Study of some improved shellac derivatives as microencapsulating materials.  

PubMed

Shellac was chemically modified to alter its permeability and to prevent its 'after hardening'. Various shellac derivatives such as with succinic anhydride, phthalic anhydride, ethylenediamine and myristic acid were prepared. Salicylic acid granules were coated and evaluated for flow properties, moisture absorption and release characteristics before and after ageing. These derivatives imparted better flow properties and showed excellent ageing properties. PMID:1941444

Sheorey, D S; Kshirsagar, M D; Dorle, A K

294

Modern Chemical Technology, Guidebook for Chemical Technicians.  

ERIC Educational Resources Information Center

|This volume is a part of the ACS "Modern Chemical Technology" (ChemTeC) curriculum that is developed for chemical technicians. It is intended as a handbook that will be used throughout the instruction. Safety is stressed in eight of the ten chapters under the headings: safety in the chemical laboratory, personal protective equipment, fire safety…

Pecsok, Robert L.; Chapman, Kenneth

295

Microfluidic chemical reaction circuits  

DOEpatents

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.

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

296

Algal Sensory Chemical Ecology  

Microsoft Academic Search

Sensory chemical ecology is the branch of chemical ecology that focuses on chemical communications between organisms and chemical\\u000a sensing of the environment by organisms. Algae are well known to have numerous physiological responses to variations in their\\u000a chemical environment, particularly with respect to nutrients (Lobban and Harrison 1994). However, with respect to environmental\\u000a sensing it is typical for “chemical ecology”

Charles D. Amsler

297

Nature's chemicals and synthetic chemicals: Comparative toxicology  

SciTech Connect

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.

Ames, B.N.; Profet, M.; Gold, L.S. (Univ. of California, Berkeley (USA))

1990-10-01

298

Mesomorphic Derivatives Of Ferrocene  

Microsoft Academic Search

The first series of ferrocene derivatives exhibiting mesomorphic properties (substituted N-(p-benzoyloxybenzylidene) anilines la and 1b) has been synthesized for application in Mössbauer spectroscopy.

Jacques Malthete; Jean Billard

1976-01-01

299

Antiestrogenic activity of anthropogenic and natural chemicals.  

PubMed

A number of natural and man-made chemicals possess antiestrogenic activity, i.e. they antagonize a broad spectrum of estrogen-induced responses in vertebrates. Examples of antiestrogens include dioxin, furan and PCB congeners, certain PAHs, pesticides and indol-3-carbinol derivatives. Major mechanisms of anti-estrogenicity are antagonistic action of chemicals at the estrogen receptor, or binding of chemicals to the arylhydrocarbon (Ah) receptor and subsequent interaction with estrogen-responsive genes. Toxicological consequences resulting from antiestrogenic activity have not been conclusively demonstrated to date, although antiestrogenic compounds could critically affect sensitive reproductive and developmental processes. PMID:19005814

Navas, J M; Segner, H

1998-01-01

300

TECHNICAL BASIS FOR NARCOTIC CHEMICALS AND POLYCYCLIC AROMATIC HYDROCARBON CRITERIA. I. WATER AND TISSUE  

Microsoft Academic Search

A method is presented for developing water quality criteria (WQC) for type I narcotic chemicals in general and PAHs in particular. The criteria can be applied to any individual or mixture of narcotic chemicals using only the chemical's octanol-water partition coefficient KOW. It is derived from a database of LC50s comprising 156 chemicals and 33 species, including fish, amphibians, arthropods,

Dominic M. Di Toro; Joy A. McGrath; David J. Hansen

2000-01-01

301

Irregularities in Imperfective Derivation  

ERIC Educational Resources Information Center

|This article discusses presentation of Russian conjugation via the one-stem system advocated by Lipson and Townsend, and attempts a more unified and complete presentation of irregularities in imperfect derivation. Two major irregularities are occurrence of an unexpected suffix and unpredictable alternation in the root of the derived imperfective.…

Levin, Maurice I.

1977-01-01

302

New 23-spirocholestane derivatives from Ypsilandra thibetica.  

PubMed

Three new unusual 23-spirocholestane derivatives, ypsilanogenin (1), ypsilanogenin 3-O-?-D-glucopyranoside (2), and 4'-acetylypsilanogenin 3-O-?-D-glucopyranoside (3), were isolated from the whole plants of Ypsilandra thibetica. The structures of compounds 1-3 were deduced by spectroscopic and chemical methods, and the structure of 1 was further confirmed by a single-crystal diffraction analysis. All isolates were evaluated for their inhibitory activities against HIV-1. PMID:23818269

Xie, Bai-Bo; Chen, Chang-Xiang; Guo, Yong-Hui; Li, Yu-Ye; Liu, Ya-Juan; Ni, Wei; Yang, Liu-Meng; Gong, Ning-Bo; Zheng, Yong-Tang; Wang, Rui-Rui; Lü, Yang; Liu, Hai-Yang

2013-07-01

303

Olefin recovery via chemical absorption  

SciTech Connect

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.

Barchas, R. [Stone & Webster Engineering Corporation, Houston, TX (United States)

1998-06-01

304

Chemical Basis for Photomutagenicity in Synthetic Fuels.  

National Technical Information Service (NTIS)

Photomutagens (chemicals that enhance the mutagenicity of near uv-visible radiation) have been detected in a variety of experimental coal- and oil shale-derived synthetic fuels using S. typhimurium strain TA98 and fluorescent light. In this study, photomu...

C. P. Selby J. Calkins H. G. Enoch C. W. Wright B. W. Wilson

1985-01-01

305

Chemical and electrochemical basis of bioleaching processes  

Microsoft Academic Search

The bioleaching of sulfide minerals involves electrochemical and chemical reactions of the mineral with the leach liquor and the extra-cellular polysaccharide layers on the microorganisms. The microorganisms derive energy by oxidising the sulfur moiety and ferrous iron, which can be interpreted using electrochemistry and chemiosmotic theory. Recently, significant advances have been made in understanding the mechanism by which the bioleaching

G. S Hansford; T Vargas

2001-01-01

306

Derivation of Biomonitoring Equivalents for cyfluthrin.  

PubMed

Recent efforts worldwide have resulted in a growing database of measured concentrations of chemicals in blood and urine samples taken from the general population. However, few tools exist to assist in the interpretation of the measured values in a health risk context. Biomonitoring Equivalents (BEs) are defined as the concentration or range of concentrations of a chemical or its metabolite in a biological medium (blood, urine, or other medium) that is consistent with an existing health-based exposure guideline, and are derived by integrating available data on pharmacokinetics with existing chemical risk assessments. This study reviews available health-based exposure guidance values for cyfluthrin from Health Canada, the United States Environmental Protection Agency (USEPA), and the World Health Organization/Food and Agriculture Organization. BE values corresponding to the oral reference dose (RfD), or acceptable daily intake (ADI) estimates from these agencies were derived based on data on excretion fractions of the urinary metabolite 4-fluoro-3-phenoxybenzoic acid (FPBA), which is a metabolite specific to cyfluthrin. These values may be used as screening tools for evaluation of biomonitoring data for cyfluthrin as the metabolite FPBA in the context of existing risk assessments and for prioritization of the potential need for additional risk assessment efforts for cyfluthrin relative to other chemicals. PMID:19751788

Hays, Sean M; Aylward, Lesa L; Gagné, Michelle; Krishnan, Kannan

2009-09-12

307

RESRAD-CHEM: A computer code for chemical risk assessment  

SciTech Connect

RESRAD-CHEM is a computer code developed at Argonne National Laboratory for the U.S. Department of Energy to evaluate chemically contaminated sites. The code is designed to predict human health risks from multipathway exposure to hazardous chemicals and to derive cleanup criteria for chemically contaminated soils. The method used in RESRAD-CHEM is based on the pathway analysis method in the RESRAD code and follows the U.S. Environmental Protection Agency`s (EPA`s) guidance on chemical risk assessment. RESRAD-CHEM can be used to evaluate a chemically contaminated site and, in conjunction with the use of the RESRAD code, a mixed waste site.

Cheng, J.J.; Yu, C.; Hartmann, H.M.; Jones, L.G.; Biwer, B.M.; Dovel, E.S.

1993-10-01

308

A thermodynamic derivation of the reciprocal relations.  

PubMed

Starting with the continuity and Smoluchowski equations, we write the mass flux for a system out of equilibrium in terms of the physicochemical potential ?(g). ?(g) is a coarse-grained analog of the chemical potential in the presence of forces that drive the system out of equilibrium. The expression for flux in terms of ?(g) allows for a macroscopic derivation of the Onsager reciprocal relations for the case of transport by diffusion and drift in single or multi-component systems, without recourse to microscopic fluctuations or equations of motion. Transport coefficients for any time reversal-invariant properties now are expressed in terms of only partial molar derivatives and mobilities (diffusion coefficients). The thermodynamic derivation cannot treat time reversal. PMID:23556731

Kocherginsky, N; Gruebele, M

2013-03-28

309

Bioconversion of coal-derived synthesis gas to liquid fuels. Final technical report, September 1, 1990--August 31, 1991.  

National Technical Information Service (NTIS)

The use of coal-derived synthesis gas as an industrial feedstock for production of fuels and chemicals has become an increasingly attractive alternative to present petroleum-based chemicals production. However, one of the major limitations in developing s...

M. K. Jain

1991-01-01

310

Platform Chemicals from an Oilseed Biorefinery  

SciTech Connect

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.

Tupy, Mike; Schrodi Yann

2006-11-06

311

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...

312

Higher Derivative Gravity.  

National Technical Information Service (NTIS)

A possible classical route conducting towards a general relativity theory with higher-derivatives starting, in a sense, from first principles, is analysed. A completely causal vacuum solution with the symmetries of the Goedel universe is obtained in the f...

A. J. Accioly

1987-01-01

313

Ferrocene and Ferrocene Derivatives.  

National Technical Information Service (NTIS)

This is an annotated bibliography covering ferrocene and its derivatives from 1962 to August 1966. Several review articles are listed which describe the unique characteristics of ferrocene since its discovery in 1951, its reactions, and some of its uses. ...

W. P. McNutt C. U. Pittman

1966-01-01

314

Neuroprotective Ganglioside Derivatives.  

National Technical Information Service (NTIS)

In this study, neuroprotective ganglioside derivatives are examined so they can be targeted to specific points in cell death pathways. Here, ganglioside functional groups required for neuroprotection and blood-brain barrier permeance are determined. Cell ...

M. D. Ullman

2003-01-01

315

Deriving Common Model Characteristics  

NSDL National Science Digital Library

In this activity, students confront several different models - from the DNA helix Watson and Crick constructed in their laboratory to a map of McDonalds density in the US - and work in small groups to derive their commonalities.

Momsen, Jennifer; Long, Tammy M.; Speth, Elena B.

316

Combinatorics of Partial Derivatives  

Microsoft Academic Search

The natural forms of the Leibniz rule for the kth derivative of a product and of Fa a di Bruno's formula for the kth derivative of a composition involve the dif- ferential operator @k=@x1 @xk rather than dk=dxk, with no assumptions about whether the variables x1;:::;xk are all distinct, or all identical, or partitioned into several distinguishable classes of indistinguishable

Michael Hardy

2006-01-01

317

On higher derivative gravity  

Microsoft Academic Search

A possible classical route conducting towards a general relativity theory with higher-derivatives starting, in a sense, from first principles, is analysed. A completely causal vacuum solution with the symmetries of the Goedel universe is obtained in the framework of this higher-derivative gravity. This very peculiar and rare result is the first known vacuum solution of the fourth-order gravity theory that

A. J. Accioly

1987-01-01

318

Derivative beliefs and evaluations  

Microsoft Academic Search

Purpose – The purpose of this research is to examine how consumers form beliefs and evaluate derivatives (e.g. handheld computers) and branded derivatives (e.g. Palm handheld computers). The aim is to study how consumers combine two categories (e.g. “handheld products” and “computers”) to form beliefs, how the similarity between the categories influences beliefs, how the addition of a brand changes

Daniel A. Sheinin; Laurette Dubé; Bernd H. Schmitt

2008-01-01

319

Empirical NMR Chemical Shift Correlations for Methyl and Methylene Protons.  

ERIC Educational Resources Information Center

|Presents an internally consistent set of 63 substituent constants developed for use with the Schoolery Relationship to predict the chemical shifts of methylene protons of acyclic compounds. Chemical shift data used in deriving the constants were taken mainly from primary sources of HNMR (nuclear magnetic resonance) spectra. (JN)|

Friedrich, Edwin C.; Runkle, Katherine Gates

1984-01-01

320

Mechanical, chemical, and electrical constraints and hydrodynamic interfacial instability  

Microsoft Academic Search

Threshold conditions are derived for the onset of convection in infinite plane and spherical surfaces with chemical, mechanical, and electrical constraints. A linear stability analysis is used and the role of the following factors is discussed: diffusion coefficients, viscosity coefficients, surface chemical processes, the adsorption-desorption step, the surface activity, the surface charge and the surface electric potential, interactions between surface

A. Sanfeld; A. Steinchen; M. Hennenberg; P. Bisch; D. Van Lamsweerde-Gallez; W. Dalle-Vedove

1979-01-01

321

Magnetic-resonance-based system for chemical agent screening  

Microsoft Academic Search

Quantum Magnetics is developing a system based on magnetic resonance (MR), combined with a proprietary technology, to screen for chemical agents in nonmetallic containers, without the need to open the container. It derives from the successful design and testing of a similar system for detecting liquid explosives. Preliminary measurements indicate that the system promises to quickly screen for many chemical

Sankaran Kumar; Erik E. Magnuson; David E. Newman; Pablo J. Prado; Jess Lawton

2003-01-01

322

Solar-driven chemical energy source for a Martian biota  

Microsoft Academic Search

Microorganisms deep in the Martian soil could derive energy indirectly from the sun via chemical reactions involving atmospheric photolysis products of the solar ultraviolet flux. The Viking discovery of a chemically uniform regolith which, though poor in organics, is rich in sulfur-containing compounds suggests reaction sequences in which sulfur is recycled through reduced and oxidized states by biologically catalyzed reactions

Benton C. Clark

1979-01-01

323

Quantum chemical 13Calpha chemical shift calculations for protein NMR structure determination, refinement, and validation  

Microsoft Academic Search

A recently determined set of 20 NMR-derived conformations of a 48-residue all-alpha-helical protein, (PDB ID code 2JVD), is validated here by comparing the observed 13Calpha chemical shifts with those computed at the density functional level of theory. In addition, a recently introduced physics-based method, aimed at determining protein structures by using NOE-derived distance constraints together with observed and computed 13Calpha

Jorge A. Vila; James M. Aramini; Paolo Rossi; Alexandre Kuzin; Min Su; Jayaraman Seetharaman; Rong Xiao; Liang Tong; Gaetano T. Montelione; Harold A. Scheraga

2008-01-01

324

40 CFR 721.1225 - Benzene, 1,2-dimethyl-, poly-propene derivatives, sulfonated, po-tas-sium salts.  

Code of Federal Regulations, 2013 CFR

...1,2-dimethyl-, poly-propene derivatives, sulfonated, po-tas-sium salts. 721.1225 Section 721.1225 Protection...1,2-dimethyl-, poly-propene derivatives, sulfonated, po-tas-sium salts. (a) Chemical substances and...

2013-07-01

325

40 CFR 721.1225 - Benzene, 1,2-dimethyl-, poly-propene derivatives, sulfonated, po-tas-sium salts.  

Code of Federal Regulations, 2010 CFR

...1,2-dimethyl-, poly-propene derivatives, sulfonated, po-tas-sium salts. 721.1225 Section 721.1225 Protection...1,2-dimethyl-, poly-propene derivatives, sulfonated, po-tas-sium salts. (a) Chemical substances and...

2010-07-01

326

Chemical Methods for the Synthesis and Modification of Neoclerodane Diterpenes  

PubMed Central

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.

Lozama, Anthony; Prisinzano, Thomas E.

2009-01-01

327

Chemical methods for the synthesis and modification of neoclerodane diterpenes.  

PubMed

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

Lozama, Anthony; Prisinzano, Thomas E

2009-07-17

328

Modeling effect of chemical–mechanical synergy on material removal at molecular scale in chemical mechanical polishing  

Microsoft Academic Search

This paper proposed a novel mathematical model to fully describe the influence of chemical mechanical synergy (CMS) on material removal in chemical mechanical polishing (CMP) of wafer at molecular scale. A general equation is derived on the basis of molecular scale removal mechanism and micro-contact theory. It is shown that the relative velocity-removal rate relation follows the trend similar to

Yongguang Wang; Yongwu Zhao; Jianzhong Jiang; Xufang Li; Jing bai

2008-01-01

329

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

Code of Federal Regulations, 2013 CFR

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

2013-07-01

330

Mechanistic insight into the DPPH radical-scavenging activity of hydroxystilbene derivatives  

Microsoft Academic Search

Resveratrol is a naturally occurring hydroxystilbene derived from grapes and possesses multiple biological activities. Resveratrol and many hydroxystilbene derivatives exhibit antioxidant potential and can scavenge various free radicals, such as DPPH radical. In the present paper, with the aim to elucidate the mechanism underlying how DPPH radical is scavenged by hydroxystilbene derivatives, quantum chemical calculations were performed to estimate the

Liang Shen

2011-01-01

331

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 false Carbon black derived from the pyrolysis of...Chemical Substances § 721.10579 Carbon black derived from the pyrolysis of...substance identified generically as carbon black derived from the pyrolysis...

2013-07-01

332

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

Code of Federal Regulations, 2010 CFR

...2009-07-01 false Oxo-substituted amino-al-kanoic acid derivative. 721.430... § 721.430 Oxo-substituted amino-al-kanoic acid derivative. (a) Chemical...identified generically as oxo-substituted amino al-kan-oic acid derivative (PMN...

2009-07-01

333

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... § 721.430 Oxo-substituted amino-al-kanoic acid derivative. (a) Chemical...identified generically as oxo-substituted amino al-kan-oic acid derivative (PMN...

2010-07-01

334

Chemical and radiation-chemical radical reactions in lignocellulose materials  

NASA Astrophysics Data System (ADS)

Chemical and radiation-chemical radical reactions in lignocellulose materials were explored by 3-cm and 2-mm ESR spectroscopy. Background (intrinsic) singlet signals at g=2.003 from wood pulp and lignin and those arising during reaction of lignocellulose materials with acids and chlorine were attributed to radicals with conjugated C=C bonds. The 2-mm ESR signal with 3D anisotropy of g-factor from o-semiquinone radical ions formed in reaction of lignin with NaOH was recorded for the first time. The singlet signals derived from cellulose ?-irradiated at 77 K and marked out during post-thermal reactions were assigned to radicals with conjugated bonds. In wetted cellulose, a triplet signal with ??H?2.7 mT and imposed quadruplet structure (0.5-0.7 mT) from three ?-protons was detected at 300 K and attributed to ?4-radicals. The triplet signals derived from ?2- and ?3-radicals in pyranose cycles of cellulose exhibited higher values of ??H (3.0-3.2 mT) and lower thermal stability (up to 250 K). In radiolyzed cotton pulp, detected were ESR signals derived from formyl radicals formed upon rupture of the ?5=?6 bond in pyranose cycles. Heating up irradiated samples under ?2 was accompanied by formation of peroxide radicals. Photoinduced recombination of trapped electrons with ?1-radicals was found to proceed as a chain reaction with a kinetic length of about 25 units. Photolysis (??360 nm) of radiolyzed cellulose enhanced the disclosure of pyranose cycles and, as a result, the evolution of CO2 by a factor of 2-2.5.

Kuzina, Svetlana I.; Shilova, Irina A.; Mikhailov, Al'fa I.

2011-09-01

335

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

PubMed

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

Dhamankar, Himanshu; Prather, Kristala L J

2011-05-19

336

Lean and Chemicals Toolkit.  

National Technical Information Service (NTIS)

This Lean and Chemicals Toolkit describes practical strategies for using Lean manufacturingthe production system developed by Toyotato reduce chemical wastes while improving the operational and environmental performance of manufacturing and industrial bus...

2009-01-01

337

The Chemical Equilibrium Problem.  

National Technical Information Service (NTIS)

It has long been known that the problem of determining the equilibrium composition of a solution of chemically reacting species could be formulated as a constrained minimum problem. Previous methods for solving the chemical equilibrium problem in this for...

J. H. Bigelow

1968-01-01

338

Tobacco and chemicals (image)  

MedlinePLUS

Some of the chemicals associated with tobacco smoke include ammonia, carbon dioxide, carbon monoxide, propane, methane, acetone, hydrogen cyanide and various carcinogens. Other chemicals that are associated with chewing ...

339

Alternatives in Chemical Education  

ERIC Educational Resources Information Center

|Summarizes the educational objectives and strategies of the Chemical Technician Curriculum Project (Chem TeC), which has the primary objective of preparing a set of texts specifically for training chemical technicians. (PR)|

Pecsok, Robert L.

1971-01-01

340

Chemical Reactions (Netorials)  

NSDL National Science Digital Library

Chemical Reactions: this is a resource in the collection "Netorials". The Netorials cover selected topics in first-year chemistry including: Chemical Reactions, Stoichiometry, Thermodynamics, Intermolecular Forces, Acids & Bases, Biomolecules, and Electrochemistry.

341

Physical vs Chemical Changes  

NSDL National Science Digital Library

The phenomena are physical changes, including the crushing of a can, melting of ice, and melting of sugar, and chemical changes, including and the rusting of iron and burning of sugar. This analysis will address the chemical change component.

342

Advanced Chemical Propulsion Study.  

National Technical Information Service (NTIS)

A study was performed of advanced chemical propulsion technology application to space science (Code S) missions. The purpose was to begin the process of selecting chemical propulsion technology advancement activities that would provide greatest benefits t...

G. Woodcock D. Byers L. A. Alexander A. Krebsbach

2004-01-01

343

Children and Dairy Chemicals  

MedlinePLUS

Children & Dairy Chemicals Chemicals used to clean dairy facilities and equipment, especially dairy pipeline cleaners, pose a special risk for children. Rapid medical assessment and treatment is critical in preventing long ...

344

Chemical Structural Aging Effects.  

National Technical Information Service (NTIS)

This program is determining the individual chemical rate processes that govern the aging of ANB-3066 propellant, and it is attempting to establish the effect of chemical (compositional) changes upon the system's mechanical response to enable better utiliz...

G. E. Myers A. B. Tipton

1972-01-01

345

1,3,4-oxadiazole derivatives as potential biological agents.  

PubMed

The synthesis of novel compound libraries along with screening is a rapid and effective approach for the discovery of potential chemical agents, and it becomes an important method in pharmaceutical chemistry research. 1,3,4- oxadiazole derivatives as the typical heterocyclic compounds, exhibit a broad spectrum of biological activities and vital leading compounds for the development of chemical drugs. Herein, we focus on the synthesis and screening of novel 1,3,4-oxadiazoles derivatives with antimicrobial, antitumor or antiviral activities during the past decade. In this review, we discussed the synthetic development of 1,3,4-oxadiazoles derivatives, and also the relevant bioactivity and their prospects as the potential chemical drugs. PMID:23815585

Sun, Juan; Makawana, Jigar A; Zhu, Hai-Liang

2013-10-01

346

Emergency management of chemical weapons injuries.  

PubMed

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

Anderson, Peter D

2011-11-11

347

Application of quantum-chemical approximations to environmental problems: Prediction of physical and chemical properties of TNT and related species  

Microsoft Academic Search

This paper presents accurate predictions of ecologically important properties of nitroaromatic compounds and their derivatives, including vapor pressure, Henry’s law constants, water solubility, octanol\\/water partition coefficients, heats of formation and ionization potentials. The proposed technique of calculations was based on quantum-chemical methods. The relationship between the chemical structure and mentioned physico-chemical parameters of such widespread military produced contaminants as trinitrotoluene

Mohammad Qasim; Yana Kholod; Leonid Gorb; David Magers; Patricia Honea; Jerzy Leszczynski

2007-01-01

348

Physical and Chemical Change  

NSDL National Science Digital Library

Overview of physical and chemical changes with practice activities and a quiz. Worksheet - Physical Chemical Change Worksheet After viewing the worksheet, copy and paste it into a new blank Google Document - MyDSD Google Login Title your Document "Chemical and Physical Change". Make sure to include your name and period in the body of the doc. The answers in your document should be a different color or font. Examples of Chemical Changes Changes info page More Examples After completing the rest ...

Wood, Mr.

2010-11-15

349

Chemical Synthesis Database  

NSDL National Science Digital Library

This database provides information on thousands of chemical compounds, including synthesis references and physical properties. The database is searchable by keyword and browseable by journal title. For each compound, the information includes molecular formula and weight, Chemical Abstracts Service (CAS) numbers, International Chemical Identifier (InChIKey), and Simplified Molecular Input Line Entry System (SMILES) notation. There is also information on synonyms, physical properties (boiling and melting points, density), an illustration of chemical structure, spectral data, and links to additional data.

350

Chemical of the Week  

NSDL National Science Digital Library

Professor Bassam Z. Shakhashiri at the University of Wisconsin-Madison adds a new chemical to this page every week. The site was created for his general chemistry courses, Chem 103 and Chem 104, to increase students' knowledge about various chemicals and their use. Users can view featured chemicals from the currently updated fall course (103) or from the spring course (104). The chemicals featured thus far include: lime, methane, uranium, the chemistry of autumn colors, and gases that emit light.

Shakhashiri, Bassam Z.

1997-01-01

351

The elusive chemical potential  

NSDL National Science Digital Library

The author offers some qualitative understanding of the chemical potential, a topic that students invariably find difficult. Three "meanings" for the chemical potential are stated and then supported by analytical development. Two substantial applications â depression of the melting point and batteries â illustrate the chemical potential in action. The origin of the term "chemical potential" has its surprises, and a sketch of the history is given.variable particle number.

Baierlein, Ralph

2011-08-31

352

Epoxide-derived organosulfates  

NASA Astrophysics Data System (ADS)

Organosulfates (OS) are a significant fraction of secondary organic aerosol (SOA) material in the atmosphere. OS are typically surface-active, and have been suggested to cause surface tension depression in aerosols. Recent field studies suggest that epoxide-derived OS are the most abundant OS type in aerosols. Time-dependent surface tension measurements and Aerosol-CIMS characterization of two epoxides and their organosulfate products are shown. ?-pinene oxide, derived from ?-pinene, shows significant surface tension depression in H2O and ammonium sulfate. Results from cis-2,3-epoxybutane-1,4-diol (BEPOX), a butadiene-derived analog to isoprene-derived epoxydiols, are also shown. In addition, using GAMMA, a photochemical box model using coupled gas- and aqueous-phase chemistry developed in the McNeill laboratory, we show the dominance of epoxide-derived OS formation over other competing OS formation mechanisms, such as radical chemistry, under both high-NOx and low-NOx scenarios.

Schwier, A. N.; Woo, J.; McNeill, V. F.

2011-12-01

353

Principles of Chemical Programming  

Microsoft Academic Search

The chemical reaction metaphor describes computation in terms of a chemical solu- tion in which molecules interact freely according to reaction rules. Chemical models use the multiset as their basic data structure. Computation proceeds by rewritings of the multiset which consume elements according to reaction conditions and pro- duce new elements according to specific transformation rules. Since the introduction of

Jean-pierre Banâtre; Pascal Fradet; Yann Radenac

2005-01-01

354

Principles of Chemical Programming  

Microsoft Academic Search

The chemical reaction metaphor describes computation in terms of a chemical solu- tion in which molecules interact freely according to reaction rules. Chemical models use the multiset as their basic data structure. Computation proceeds by rewritings of the multiset which consume elements according to reaction conditions and pro- duce new elements according to specic transformation rules. Since the introduction of

Jean-Pierre Ban; Pascal Fradet; Yann Radenac; Campus de Beaulieu

2004-01-01

355

Biological and Chemical Security  

Microsoft Academic Search

The LLNL Chemical & Biological National Security Program (CBNP) provides science, technology and integrated systems for chemical and biological security. Our approach is to develop and field advanced strategies that dramatically improve the nation's capabilities to prevent, prepare for, detect, and respond to terrorist use of chemical or biological weapons. Recent events show the importance of civilian defense against terrorism.

Fitch

2002-01-01

356

Toxicology and Chemical Safety.  

ERIC Educational Resources Information Center

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)

Hall, Stephen K.

1983-01-01

357

Chemical Plume Source Localization  

Microsoft Academic Search

This paper addresses the problem of estimating a likelihood map for the location of the source of a chemical plume using an autonomous vehicle as a sensor probe in a fluid flow. The fluid flow is assumed to have a high Reynolds number. Therefore, the dispersion of the chemical is dominated by turbulence, resulting in an intermittent chemical signal. The

Shuo Pang; Jay A. Farrell

2006-01-01

358

Chemical warfare agents  

Microsoft Academic Search

Chemical warfare agents (CWA's) are defined as any chemical substance whose toxic properties are utilised to kill, injure or incapacitate an enemy in warfare and associated military operations. Chemical agents have been used in war since times immemorial, but their use reached a peak during World War I. During World War II only the Germans used them in the infamous

S. Chauhan; R. D’Cruz; S. Faruqi; K. K. Singh; S. Varma; M. Singh; V. Karthik

2008-01-01

359

Toxicology and Chemical Safety.  

ERIC Educational Resources Information Center

|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)|

Hall, Stephen K.

1983-01-01

360

More on Chemical Changes  

NSDL National Science Digital Library

The phenomenon is a series of chemical reactions and observation of signs of a chemical change. The laboratory activities can be done by students or as a teacher demonstration. They involve mixing chemicals and noting color change, formation of a precipitate, and production of a gas.

361

Chemical etching of aluminium  

Microsoft Academic Search

Chemical etching is employed as micromachining manufacturing process to produce micron-size components. The process applies a strong chemical etchant solution to remove unwanted part in the workpiece material. It is basically a corrosion-controlled process. Chemical etching process has a long history and accepted one of the important nontraditional machining processes during the last half century. The method is widely applied

O. Çak?r

2008-01-01

362

Adaptability in Chemical Engineering.  

National Technical Information Service (NTIS)

The adaptability issue for chemical engineering (the ability of chemical engineers to be retrained to work in other fields and for those from other fields to be retrained for work in chemical engineering) will be discussed and illustrated in terms of (1) ...

J. S. Watson

1989-01-01

363

Novel derivatives of polymyxins.  

PubMed

Polymyxin B and colistin (polymyxin E) are bactericidal pentacationic lipopeptides that act specifically on Gram-negative bacteria, first by disrupting their outermost permeability barrier, the outer membrane (OM), and then damaging the cytoplasmic membrane. Both were discovered in the mid-1950s and subsequently used in intravenous therapy, but soon largely abandoned because of nephrotoxicity. The emergence of extremely multiresistant strains has now forced clinicians to reinstate them in the therapy of severe infections caused by such strains. This article reviews recent attempts to develop novel derivatives of polymyxins that exhibit less toxicity and greater potency than the existing drugs. In addition, studies of novel des-fatty acyl-polymyxin derivatives that display activity against Pseudomonas aeruginosa are included. The review also covers recent studies of derivatives that lack potent bactericidal action, but which disrupt the OM, which increases bacterial permeability to other antibiotics, facilitating their entry into the cell. PMID:23412346

Vaara, Martti

2013-02-13

364

Myeloid derived suppressor cells  

PubMed Central

The goal of achieving measurable response with cancer immunotherapy requires counteracting the immunosuppressive characteristics of tumors. One of the mechanisms that tumors utilize to escape immunosurveillance is the activation of myeloid derived suppressor cells (MDSCs). Upon activation by tumor-derived signals, MDSCs inhibit the ability of the host to mount an anti-tumor immune response via their capacity to suppress both the innate and adaptive immune systems. Despite their relatively recent discovery and characterization, anti-MDSC agents have been identified, which may improve immunotherapy efficacy.

Waldron, Todd J.; Quatromoni, Jon G.; Karakasheva, Tatiana A.; Singhal, Sunil; Rustgi, Anil K.

2013-01-01

365

Credit Derivatives and Risk Management.  

National Technical Information Service (NTIS)

The striking growth of credit derivatives suggests that market participants find them to be useful tools for risk management. I illustrate the value of credit derivatives with three examples. A commercial bank can use credit derivatives to manage the risk...

M. S. Gibson

2007-01-01

366

Streptothricin derivatives from Streptomyces sp. I08A 1776.  

PubMed

Five new streptothricin derivatives with a carbamoyl group substituted at C-12 (1-5) and three known analogues have been isolated from the culture broth of Streptomyces sp. I08A 1776 by ion exchange and hydrophilic interaction chromatographic techniques. Their structures were determined by spectroscopic and chemical methods. Compound 3 was a streptothricin derivative possessing a cis-streptolidine moiety. Its absolute configuration was defined by comparison of quantum chemical TDDFT calculated and experimental ECD spectra. Compound 5 and streptothricin E (6) displayed antibacterial and antifungal activity with MIC values in the range 1-64 ?g/mL. PMID:21510638

Gan, Maoluo; Zheng, Xudong; Gan, Lishe; Guan, Yan; Hao, Xueqin; Liu, Yishuang; Si, Shuyi; Zhang, Yuqin; Yu, Liyan; Xiao, Chunling

2011-04-21

367

Application of quantum-chemical approximations to environmental problems: Prediction of physical and chemical properties of TNT and related species.  

PubMed

This paper presents accurate predictions of ecologically important properties of nitroaromatic compounds and their derivatives, including vapor pressure, Henry's law constants, water solubility, octanol/water partition coefficients, heats of formation and ionization potentials. The proposed technique of calculations was based on quantum-chemical methods. The relationship between the chemical structure and mentioned physico-chemical parameters of such widespread military produced contaminants as trinitrotoluene and its derivatives was considered. We revealed that the DFT level of theory combined with the COSMO-RS technique is able to predict the studied parameters with an accuracy that results in error bars of less then one logarithmic unit. PMID:17512030

Qasim, Mohammad; Kholod, Yana; Gorb, Leonid; Magers, David; Honea, Patricia; Leszczynski, Jerzy

2007-05-23

368

Make a Chemical Clock  

NSDL National Science Digital Library

This lesson for Grades 6-8 combines a short video with three experiments to observe and record chemical changes. The experiments use common household materials to demonstrate chemical reaction -- a change that leads to a transformation of one substance into another substance. In the 3rd experiment, there are two chemical reactions happening at the same time. Through careful observation, learners see that the 3rd reaction represents a "chemical clock", because the time it takes the chemicals to react happens very predictably, like a regular clock. Talking Science is part of National Public Radio's Science Friday initiative.

2011-08-18

369

Chemical composition of A and F dwarfs members of the Pleiades open cluster? (Research Note)  

Microsoft Academic Search

Aims. Abundances of 18 chemical elements have been derived for 16 A (normal and chemically peculiar CP) and 5 F dwarfs members of the Pleiades open cluster in order to set constraints on evolutionary models. Methods. The abundances, rotational velocities and microturbulent velocities were derived by iteratively adjusting syntheti c spectra to observations at high resolution (R? 42000 and R?

M. Gebran; R. Monier

370

Basic cholane derivatives. XI: Comparison between acid and basic derivatives.  

PubMed

A series of hydroxycholan-24-amines was synthesized; the carboxyl group of starting unconjugated bile acids was transformed into a basic moiety [-NH2, -NHCH3, -N(CH3)2, or -NHCH2C6H5] at C-24. Solubilities, acidities, partition coefficients, and critical micellar concentrations were measured and compared with those of the corresponding bile acids. Because the steroid nucleus in the amines is the same as that in the bile acids, most of the physical-chemical properties of the two compound classes were similar. The amines were more soluble than the corresponding acids; solubilities depended mainly on the number of steroid hydroxyls and, to a lesser extent, on the side chain. Amines are strong bases in water, whereas unconjugated bile acids can be classified as weak acids. N-Benzylamino derivatives have higher log P (P is partition coefficient) values, as a consequence of the bulky hydrophobic substituent; the log P values were almost the same for the amines and the bile acids and depended on the steroid hydroxyls. Amines can self-aggregate at an acidic pH and form cationic micelles; the critical micellar concentrations of amines were of the same order of magnitude as those of bile acids. The introduction of a basic function in the side chain of the cholane moiety increased the antimicrobial activity toward most gram-positive strains. PMID:1403713

Fini, A; Fazio, G; Roda, A; Bellini, A M; Mencini, E; Guarneri, M

1992-07-01

371

Chemical Kinetic Modeling of Advanced Transportation Fuels  

SciTech Connect

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.

PItz, W J; Westbrook, C K; Herbinet, O

2009-01-20

372

Deriving Function From Structure  

Microsoft Academic Search

\\u000a The fold and biochemical activity of a protein are tightly coupled. Once a protein is characterized, it is usual to determine\\u000a its structure in order to derive an atomic descrip- tion of its molecular mechanism. The fold reveals interaction surfaces,\\u000a ligand-binding pockets, and the precise juxtaposition of functional groups.

Annabel E. Todd

373

Chemically Prepared Lead Magnesium Niobate Dielectrics  

SciTech Connect

A chemical solution powder synthesis technique has been developed that produces fine uniform powders of lead magnesium niobate (PMN) with 60 to 80 nm crystallite size. The synthesis technique was based on the dissolution of lead acetate and alkoxide precursors in acetic acid followed by precipitation with oxalic acid/propanol solutions. Lead magnesium niobate ceramics fabricated from these chemically derived powders had smaller, more uniform grain size and higher dielectric constants than ceramics fabricated from mixed oxide powders that were processed under similar thermal conditions.

Tuttle, B.A.; Voigt, J.A.; Sipola, D.L.; Olson, W.R.; Goy, D.M.

1998-01-01

374

Chemical analysis of biomass fast pyrolysis oils  

SciTech Connect

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.

Elliott, D.C.

1994-09-01

375

Digital and analog chemical evolution.  

PubMed

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

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

2012-10-25

376

Metformin modulates insulin receptor signaling in normal and cholesterol-treated human hepatoma cells (HepG2)  

Microsoft Academic Search

The effects of the biguanide anti-hyperglycemic agent, metformin (N,N?-dimethyl-biguanide), on insulin signaling was studied in a human hepatoma cell line (HepG2). Cells were cultured in the absence (control cells) or in the presence of 100 ?M of a cholesterol derivative, hemisuccinate of cholesterol. Cholesterol hemisuccinate-treatment alters cholesterol and lipid content of HepG2 and modulates membrane fluidity. Cholesterol hemisuccinate-treatment induces a

Emmanuelle J Meuillet; Nicolas Wiernsperger; Barbara Mania-Farnell; Pierre Hubert; Gerard Cremel

1999-01-01

377

Comparison of sublethal and lethal criteria for nine different chemicals in standardized toxicity tests using the earthworm Eisenia andrei  

Microsoft Academic Search

In this study, the effects of nine different chemicals on the survival, growth, and reproduction of the earthworm species Eisenia andrei were determined using a recently developed method. Earthworms were exposed for 3 weeks to the test chemicals in an artificial soil substrate. Additional data on the acute toxicity of these chemicals were derived from the literature. For some chemicals,

C. A. Van Gestel; E. M. Dirven-Van Breemen; R. Baerselman; H. J. Emans; J. A. Janssen; R. Postuma; P. J. Van Vliet

1992-01-01

378

Toxic Chemical System (TCS)  

SciTech Connect

The Toxic Chemical System (TCS) will have the capacity to process chemical data, calculate chemical formulas, and format the data into the United States (US) Environmental Protection Agency (EPA) Toxic Chemical Release Inventory Reporting Form R of Section 313 of the Emergency Planning and Community Right-to-Know Act (EPCRA), hereafter be referred to as ``Form R.`` The filing of this form is required of all industries which manufacture, process or otherwise use any EPA listed chemicals in quantities in excess of their threshold planning quantities (TPQ). Facilities required to file the Form R must report the quantities of both routine and accidental releases of listed toxic chemicals on-site during the calendar year and the amount contained in waste products transferred off-site. This paper describes a specialized computer system designed for regulatory compliance.

Del Gandio, P.

1994-09-01

379

Producer Welfare Consequences of Regulating Chemical Residues on Agricultural Crops: Maleic Hydrazide and Flue Cured Tobacco  

Microsoft Academic Search

A procedure is presented to calculate welfare consequences of chemical regulation from demand curves when input applications are unobserved, and is applied to maleic hydrazide and tobacco. The relationship between chemical residues and weather variables and prices is estimated, and from this the authors derive demand curves using an application-residue relationship estimated using research station data. Chemical price levels required

William E. Foster; Bruce A. Babcock

1991-01-01

380

TECHNICAL BASIS FOR NARCOTIC CHEMICALS AND POLYCYCLIC AROMATIC HYDROCARBON CRITERIA. II. MIXTURES AND SEDIMENTS  

Microsoft Academic Search

A method is presented for developing sediment quality guidelines (SQG) for narcotic chemicals in general and polycyclic aromatic hydrocarbons (PAHs) in particular. The guidelines can be applied to any individual or mixture of narcotic chemicals including PAHs using only the chemical's octanol\\/water partition coefficient. They are derived using the final chronic values for type I narcotics developed from a database

Dominic M. Di Toro; Joy A. McGrath

2000-01-01

381

Photochemical ozone creation potentials for organic compounds in northwest Europe calculated with a master chemical mechanism  

Microsoft Academic Search

Master Chemical Mechanism containing over 2400 chemical species and over 7100 chemical reactions is employed here to describe the atmospheric degradation of 120 organic compounds and the associated regional scale ozone and PAN formation under conditions appropriate to the polluted boundary layer over northwest Europe. Photochemical ozone and PAN creation potentials (POCP and PPCP) are derived for each organic compound

Richard G. Derwent; Michael E. Jenkin; Sandra M. Saunders; Michael J. Pilling

1998-01-01

382

Rapid biomass analysis: New analytical methods supporting fuels and chemical production from biomass  

Microsoft Academic Search

The ability to obtain an accurate chemical composition of biomass and biomass-derived samples using rapid and inexpensive methods is a key element supporting commercialization of processes that convert biomass to fuels and chemicals. The development and demonstrated use of rapid analysis methods for chemical characterization of feedstocks, process intermediates and solid residues will be presented. The new techniques being presented

Bonnie R. Hames; Amie D. Sluiter; Chris J. Roth; Robert R. Meglen

383

Potential Health Hazards of Organic Pigments and Dyes Used in the Manufacture of Paints and Surface Coatings. Appendix I: Scientific Basis for the Proposed Regulation of Dyes Derived from the Chemical Substances Benzidine, 3,3'-Dimethylbenzidine, and 3,3'-Dimethoxybenzidine,  

National Technical Information Service (NTIS)

The scientific bases for regulating dyes derived from benzidine (92875), 3,3'-dimethylbenzidine (119937), and 3,3'-dimethoxybenzidine (119904) are presented. Studies of these compounds have demonstrated that benzidine type dyes undergo nearly complete cle...

C. L. Jenkins

1978-01-01

384

QCD sign problem as a total derivative  

NASA Astrophysics Data System (ADS)

We consider the distribution of the complex phase of the fermion determinant in QCD at nonzero chemical potential and examine the physical conditions under which the distribution takes a Gaussian form. We then calculate the baryon number as a function of the complex phase of the fermion determinant and show 1) that the exponential cancellations produced by the sign problem take the form of total derivatives, and 2) that the full baryon number is orthogonal to this noise. These insights allow us to define a self-consistency requirement for measurements of the baryon number in lattice simulations.

Greensite, Jeff; Myers, Joyce C.; Splittorff, K.

2013-08-01

385

Miniature chemical measurement systems  

SciTech Connect

Prospect of microfabricated monolithic devices that accomplish complete chemical assays is enticing. Early work with microfabricated chemical analysis devices focused on separations methods. More recently reagent manipulation has been integrated with separation devices to create more powerful capabilities. Examples of procedures, other than separations, that have been demonstrated on micromachined structures include reagent mixing, dilution, and reaction, preconcentration through sample stacking and biopolymer tagging for detection. Developments in liquid phase microfabricated chemical analysis devices are reviewed.

Ramsey, J.M.

1996-12-31

386

Chemical warfare agents  

Microsoft Academic Search

\\u000a Chemical warfare agents are compounds of different chemical structures. Simple molecules such as chlorine as well as complex\\u000a structures such as ricin belong to this group. Nerve agents, vesicants, incapacitating agents, blood agents, lung-damaging\\u000a agents, riot-control agents and several toxins are among chemical warfare agents. Although the use of these compounds is strictly\\u000a prohibited, the possible misuse by terrorist groups

Kamil Ku?a; Miroslav Pohanka

387

Derivation of equations describing solute transport in ground water  

USGS Publications Warehouse

A general equation describing the three-dimensional transport and dispersion of a reacting solute in flowing ground water is derived from the principle of conservation of mass. The derivation presented is more detailed but less rigorous than derivations published previously. The general solute-transport equation relates concentration changes to hydrodynamic dispersion, convective transport, fluid sources and sinks, and chemical reactions. Because both dispersion and convective transport depend on the velocity of ground-water flow, the solute-transport equation must be solved in conjunction with the ground-water flow equation. (Woodard-USGS)

Konikow, L. F.; Grove, D. B.

1977-01-01

388

Physical and Chemical Changes  

NSDL National Science Digital Library

Physical and chemical changes in matter affect us every day. Use the following resources to help you understand these changes more completely. Read this document to help you understand the difference between physical and chemical changes in matter. definitions Watch this! It illustrates the physical change of matter. physical change video Now, watch this! It illustrates the chemical change of matter. chemical change video Click on this link to read and explore the Utah Science Sci-ber Site. It will help you to ...

Holly, Mrs.

2010-11-15

389

310 Facility chemical specifications  

SciTech Connect

The 300 area Treated Effluent Disposal Facility (TEDF) was designed and built to treat the waste water from the 300 area process sewer system. Several treatment technologies are employed to remove the trace quantities of contaminants in the stream, including iron coprecipitation, clarification, filtration, ion exchange, and ultra violet light/hydrogen peroxide oxidation of organics. The chemicals that will be utilized in the treatment process are hydrogen peroxide, sulfuric acid, sodium hydroxide, and ferric chloride. This document annotates the required chemical characteristics of TEDF bulk chemicals as well as the criteria that were used to establish these criteria. The chemical specifications in appendix B are generated from this information.

Hagerty, K.J.

1997-05-21

390

RFE Chemical Taxonomy  

Center for Food Safety and Applied Nutrition (CFSAN)

... In chemical taxonomic identification ("chemotaxonomy") the comparison of characteristic gel banding patterns from biochemical analyses are used ... More results from www.fda.gov/food/foodscienceresearch/rfe

391

Apparatus for chemical synthesis  

SciTech Connect

A method and apparatus for forming a chemical hydride is described and which includes a pseudo-plasma-electrolysis reactor which is operable to receive a solution capable of forming a chemical hydride and which further includes a cathode and a movable anode, and wherein the anode is moved into and out of fluidic, ohmic electrical contact with the solution capable of forming a chemical hydride and which further, when energized produces an oxygen plasma which facilitates the formation of a chemical hydride in the solution.

Kong, Peter C. (Idaho Falls, ID); Herring, J. Stephen (Idaho Falls, ID); Grandy, Jon D. (Idaho Falls, ID)

2011-05-10

392

Ionospheric chemical releases  

SciTech Connect

Ionospheric plasma density irregularities can be produced by chemical releases into the upper atmosphere. F-region plasma modification occurs by (1) chemically enhancing the electron number density, (2) chemically reducing the electron population, or (3) physically convecting the plasma from one region to another. The three processes (production, loss, and transport) determine the effectiveness of ionospheric chemical releases in subtle and surprising ways. Initially, a chemical release produces a localized change in plasma density. Subsequent processes, however, can lead to enhanced transport in chemically modified regions. Ionospheric modification by chemical releases excites artificial enhancements in airglow intensities by exothermic chemical reactions between the newly created plasma species. Numerical models have been developed to describe the creation and evolution of large scale (>l km) density irregularities and airglow clouds generated by artificial means. Experimental data compares favorably with these models. In general, we find that chemical releases produce transient, large amplitude perturbations in electron density which can evolve into fine scale irregularities via nonlinear transport processes.

Bernhardt, P.A.; Scales, W.A.

1990-10-01

393

Automated compound classification using a chemical ontology  

PubMed Central

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.

2012-01-01

394

Predicting Chemical Toxicity Effects Based on Chemical-Chemical Interactions  

PubMed Central

Toxicity is a major contributor to high attrition rates of new chemical entities in drug discoveries. In this study, an order-classifier was built to predict a series of toxic effects based on data concerning chemical-chemical interactions under the assumption that interactive compounds are more likely to share similar toxicity profiles. According to their interaction confidence scores, the order from the most likely toxicity to the least was obtained for each compound. Ten test groups, each of them containing one training dataset and one test dataset, were constructed from a benchmark dataset consisting of 17,233 compounds. By a Jackknife test on each of these test groups, the 1st order prediction accuracies of the training dataset and the test dataset were all approximately 79.50%, substantially higher than the rate of 25.43% achieved by random guesses. Encouraged by the promising results, we expect that our method will become a useful tool in screening out drugs with high toxicity.

Zhang, Jian; Feng, Kai-Rui; Zheng, Ming-Yue; Cai, Yu-Dong

2013-01-01

395

ALTERNATIVE FUELS AND CHEMICALS FROM SYNTHESIS GAS  

SciTech Connect

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.

Unknown

1999-04-01

396

Modelling chemical depletion profiles in regolith  

Microsoft Academic Search

Chemical or mineralogical profiles in regolith display reaction fronts that document depletion of leachable elements or minerals. A generalized equation employing lumped parameters was derived to model such ubiquitously observed patterns:C=C0C0?Cx=0Cx=0exp(?ini·kˆ·x)+1Here C, Cx=0, and Co are the concentrations of an element at a given depth x, at the top of the reaction front, or in parent respectively. ?ini is the

S. L. Brantley; J. Bandstra; J. Moore; A. F. White

2008-01-01

397

Alternative Fuels and Chemicals From Synthesis Gas  

SciTech Connect

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.

none

1998-07-01

398

Alternative fuels and chemicals from synthesis gas  

SciTech Connect

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.

Unknown

1998-08-01

399

ALTERNATIVE FUELS AND CHEMICALS FROM SYNTHESIS GAS  

SciTech Connect

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.

Unknown

2001-12-31

400

ALTERNATIVE FUELS AND CHEMICALS FROM SYNTHESIS GAS  

SciTech Connect

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.

Unknown

2000-10-01

401

ALTERNATIVE FUELS AND CHEMICALS FROM SYNTHESIS GAS  

SciTech Connect

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.

Unknown

1999-07-01

402

ALTERNATIVE FUELS AND CHEMICALS FROM SYNTHESIS GAS  

SciTech Connect

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.

Peter Tijrn

2003-02-03

403

ALTERNATIVE FUELS AND CHEMICALS FROM SYNTHESIS GAS  

SciTech Connect

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.

Unknown

2001-09-30

404

ALTERNATIVE FUELS AND CHEMICALS FROM SYNTHESIS GAS  

SciTech Connect

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.

Peter J. Tijrn

2000-06-30

405

ALTERNATIVE FUELS AND CHEMICALS FROM SYNTHESIS GAS  

SciTech Connect

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.

Unknown

1999-01-01

406

ALTERNATIVE FUELS AND CHEMICALS FROM SYNTHESIS GAS  

SciTech Connect

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.

NONE

1999-10-01

407

Metamorphic chemical geodynamics of subduction zones  

Microsoft Academic Search

Study of metamorphic suites directly representing the deep subduction of altered oceanic crust and sediments can help elucidate the geochemical evolution of the forearc-to-subarc slab mantle interface, the nature of slab-derived fluids added to arc lava source regions, and the chemical changes in subducting rocks potentially contributing to the geochemical heterogeneity of the deeper mantle. The stage is set for

Gray E. Bebout

2007-01-01

408

Alternative Fuels and Chemicals from Synthesis Gas  

SciTech Connect

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.

Peter Tijrn

2003-01-02

409

ALTERNATIVE FUELS AND CHEMICALS FROM SYNTHESIS GAS  

SciTech Connect

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.

Peter J. Tijrn

2000-09-30

410

Biolubricant basestocks from chemically modified ricinoleic acid  

Microsoft Academic Search

This paper presents a series of chemically modified biolubricant basestocks derived from ricinoleic acid. The reactions were monitored and products were confirmed by NMR and FTIR. The synthesis protocol is carried out in three stages: (1) epoxidation of ricinoleic acid; (2) synthesis of 10,12-dihydroxy-9-acyloxystearic acid from epoxidized ricinoleic acid; (3) esterification of the acyloxystearic acid products with 2-ethylhexanol to yield

Jumat Salimon; Nadia Salih; Emad Yousif

2010-01-01

411

CHEMICAL STUDIES ON BACTERIAL AGGLUTINATION  

PubMed Central

1. By the application of an absolute, quantitative microchemical method for the estimation of agglutinins, precise data have been obtained on the course of the agglutination of Type I pneumococcus by homologous anticarbohydrate. 2. Within the limitations imposed by the necessity for the agglutination reaction to take place at the bacterial surface, the reaction is shown to be analogous to the precipitin reaction and subject to the same laws. 3. The entire process of a typical instance of specific bacterial agglutination has been quantitatively accounted for on a purely chemical basis and expressed in the form of equations derived from the law of mass action. 4. Experimental verification of predictions based on the theory has shown a fundamental difference between this instance of specific bacterial agglutination and the commonly adduced analogies, and necessitated a revision of current conceptions regarding the rôle of electrolytes and of physical forces in the reaction.

Heidelberger, Michael; Kabat, Elvin A.

1937-01-01

412

Fabrication of optical film derived from biomass using eco-friendly nanoimprint lithography  

NASA Astrophysics Data System (ADS)

This paper presents the chemical design and fabrication of optical film derived from biomass using eco-friendly nanoimprint lithography. The optical film derived from biomass with subwavelength structures was successfully demonstrated in specific desired properties. The linearly polymerized polysaccharide in optical film derived from biomass indicated two effects of high concentration of acrylate group in the side-chain terminus for highly sensitivity, and the ring components containing bulky disaccharide for suitable optical properties. The optical film derived from biomass is applicable to future development of antireflective material with subwavelength structures and suitable refractive index material as a chemical design concept.

Takei, Satoshi; Murakami, Gaku; Mori, Yuto; Ichikawa, Takumi; Sekiguchi, Atsushi; Obata, Tsutomu; Yokoyama, Yoshiyuki; Mizuno, Wataru; Sumioka, Junji; Horita, Yuji

2013-03-01

413

CHEMICAL CATEGORIES IN EPA'S NEW CHEMICALS PROGRAM  

EPA Science Inventory

Under section 5 of the Toxic Substances Control Act (TSCA),any person who intends to manufacture or import a new chemical substance, or mixture containing such a substance, in the United States for commercial purposes must submit a premanufacture notice (PMN) to the Environmental...

414

Chemical Dynamics Special Feature: Chemical reaction dynamics  

Microsoft Academic Search

Understanding the motions of the constituent atoms in reacting molecules lies at the heart of chemistry and is the central focus of chemical reaction dynamics. The most detailed questions one can ask are about the evolution of molecules prepared in a single quantum state to products in individual states, and both calculations and experiments are providing such detailed understanding of

F. Fleming Crim

2008-01-01

415

Amaryllidaceae Isocarbostyril Alkaloids and Their Derivatives as Promising Antitumor Agents  

Microsoft Academic Search

This review covers the isolation, total synthesis, biologic activity, and more particularly the in vitro and in vivo anti- tumor activities of naturally occurring isocarbostyril alkaloids from the Amaryllidaceae family. Starting from these natural products, new derivatives have been synthesized to explore structure-activity relationships within the chemical class and to obtain potential candidates for preclinical development. This approach appears to

Laurent Ingrassia; Florence Lefranc; Véronique Mathieu; Francis Darro; Robert Kiss

416

Polymeric derivatives of plant growth regulators: synthesis and properties  

Microsoft Academic Search

The polymeric formulations of plant growth regulators (PGRs) are high molecular weight systems in which the PGR unit is attached to the polymeric chain by a hydrolysable chemical bond. These polymeric derivatives (esters, ethers, or else) of PGRs are characterised by the ability to release the active compound (PGR) from their solutions (mainly aqueous) in certain conditions. The release of

Aristidis M. Tsatsakis; Michail I. Shtilman

1994-01-01

417

Sinapic acid derivatives from the seeds of Raphanus nussatirus L  

Microsoft Academic Search

A new disulfide glycoside, raphthioglucoside (1), and a new sinapic acid derivative, sinapic acid 5-hydroxymethylfurfural ester (2), together with sinapic acid (3) have been isolated from the seeds of Raphanus nussatirus L. The structures of compounds 1-3 were determined based on chemical analysis and spectroscopic methods (UV, 1D and 2D NMR, HRFABMS, HREIMS and elemental analysis).

Li-Xin Duan; Bao-Min Feng; Fang Chen; Jing-Yang Liu; Fan Li; Yong-Qi Wang; Yue-Hu Pei

2007-01-01

418

Sinapic acid derivatives from the seeds of Raphanus nussatirus L.  

PubMed

A new disulfide glycoside, raphthioglucoside (1), and a new sinapic acid derivative, sinapic acid 5-hydroxymethylfurfural ester (2), together with sinapic acid (3) have been isolated from the seeds of Raphanus nussatirus L. The structures of compounds 1-3 were determined based on chemical analysis and spectroscopic methods (UV, 1D and 2D NMR, HRFABMS, HREIMS and elemental analysis). PMID:17885845

Duan, Li-Xin; Feng, Bao-Min; Chen, Fang; Liu, Jing-Yang; Li, Fan; Wang, Yong-Qi; Pei, Yue-Hu

419

Graphene and Chemically Modified Graphene Nanomechanical Resonators  

NASA Astrophysics Data System (ADS)

The facile synthesis of solution derived graphene and CVD graphene films have enabled recent advances in the large-area fabrication of graphene-based nanoelectromechanical structures. In this talk we describe routes to fabricate nanomechanical resonators and our characterization of the resulting structures. We find chemical modification has important consequences in the mechanical response of graphene-based resonators, including quality factor (Q) and Young's modulus (E). Graphene-based resonance structures are formed from both nominally pure graphene films and chemically modified graphene (CMG) formed from graphene oxide. Critically, a composite CMG/ graphene film facilitates the formation of high-quality, low-resistance resonators for incorporation into nanoelectromechanical systems. We further discuss chemical bonding of graphene versus CMG to the underlying substrate and its effect on subsequent quality factors of the resonator structures.

Robinson, Jeremy; Zalalutdniov, Maxim; Baldwin, Jeffrey; Burgess, James; Wei, Zhongqing; Sheehan, Paul; Snow, Eric; Houston, Brian

2010-03-01

420

Chemically prepared lead magnesium niobate dielectrics  

SciTech Connect

A chemical solution powder synthesis technique has been developed that produces first, uniform powders of lead magnesium niobate (PMN) with 60 to 80 nm crystallite size. The synthesis technique was based on the dissolution of lead acetate and alkoxide precursors in acetic acid followed by precipitation with oxalic acid/propanol solutions. Lead magnesium niobate ceramics fabricated from these chemically derived powders had smaller, more uniform grain size and higher dielectric constants than ceramics fabricated from mixed oxide powders that were processed under similar thermal conditions. Chem-prep PMN dielectrics with peak dielectric constants greater than 22,000 and polarizations in excess of 29 {micro}C/cm{sup 2} were obtained for 1,100 C firing treatments. Substantial decreases in dielectric constant and polarization were measured for chemically prepared PMN ceramics fired at lower temperatures, consistent with previous work on mixed oxide materials.

Tuttle, B.A.; Voigt, J.A.; Sipola, D.L.; Olson, W.R.; Goy, D.M.

1998-11-01

421

Separations Needs for the Alternate Chemical Cycles  

SciTech Connect

The bulk of the efforts for the development of a hydrogen production plant supported by the Nuclear Hydrogen Initiative (NHI) have been directed towards the sulfur-iodine (S-I) thermochemical cycle. However, it was judged prudent to re-investigate alternate chemical cycles in light of new developments and technical accomplishments derived from the current S-I work. This work analyzes the available data for the promising alternate chemical cycles to provide an understanding of their inherent chemical separations needs. None of the cycles analyzed have separations that are potential “show stoppers”; although some of the indicated separations will be challenging to perform. The majority of the separations involve processes that are either more achievable or more developed

Frederick F. Stewart

2007-05-01

422

Access to Chemical Works  

Microsoft Academic Search

STUDENTS of chemistry so often complain of the extreme difficulty of obtaining access to chemical works that it may be well to bear in mind that the universities and technical schools of the United Kingdom have perhaps a remedy for what is a serious obstacle to a proper study of chemistry. The amount of chemicals now consumed in educational laboratories

Chemist

1908-01-01

423

Recognizing Chemical Hazards Module  

NSDL National Science Digital Library

The Center for the Advancement of Process Technology presents this free sample module on recognizing chemical hazards. It focuses on chemical hazards specific to process industries, and their impact on safety, health and the environment. The material also introduces the purpose and components of an MSDS.

2013-01-09

424

Chemicals in Everyday Life.  

ERIC Educational Resources Information Center

|Discusses the dependencies of people on chemicals in various aspects of life. Describes some of the natural and synthetic chemicals currently used in food production, clothing, shelter, travel and exploration, sports and recreation, ventilation, heating and cooling, communications, decoration, sanitation, and education. (TW)|

Seymour, Raymond B.

1987-01-01

425

Fundamentals of Chemical Processes.  

ERIC Educational Resources Information Center

|Describes a course that provides students with a fundamental understanding of the chemical, catalytic, and engineering sciences related to the chemical reactions taking place in a variety of reactors of different configurations. Also describes the eight major lecture topics, course examinations, and term papers. The course schedule is included.…

Moser, William R.

1985-01-01

426

CHEMICAL PROCESSES IN SOILS  

Technology Transfer Automated Retrieval System (TEKTRAN)

“Chemical Processes in Soils” edited by Tabatabai and D.L. Sparks (2005) is a key review useful for soil scientists, agronomists, conservationists, environmental scientists and other related professionals who need to understand these processes of chemical reactions and how they may be related to the...

427

Chemical Reaction Problem Solving.  

ERIC Educational Resources Information Center

|Discusses the role of chemical-equation problem solving in helping students predict reaction products. Methods for helping students learn this process must be taught to students and future teachers by using pedagogical skills within the content of chemistry. Emphasizes that solving chemical reactions should involve creative cognition where…

Veal, William

1999-01-01

428

The Chemical Abstract Machine  

Microsoft Academic Search

We introduce a new kind of abstract machine based on the chemical metaphor used in the ? language of Banâtre & al. States of a machine are chemical solutions where floating molecules can interact according to reaction rules. Solutions can be stratified by encapsulating subsolutions within membranes that force reactions to occur locally. We illustrate the use of this model

Gérard Berry; Gérard Boudol

1990-01-01

429

Chemical Kinetics: Isolation Method  

NSDL National Science Digital Library

This site offers an interactive tutorial that guides the student through the Method of Isolation used for the determination of chemical reaction rate laws and rate constants. This tutorial is coupled to others to further guide the student to a better understanding of chemical kinetics.

Blauch, David N.

430

Microorganisms and Chemical Pollution  

ERIC Educational Resources Information Center

|Discusses the importance of microorganisms in chemical pollution and pollution abatement. Selected chemical pollutants are chosen to illustrate that microorganisms synthesize hazardous substances from reasonably innocuous precursors, while others act as excellent environmental decontaminating agents by removing undesirable natural and synthetic…

Alexander, M.

1973-01-01

431

Great Lakes: Chemical Monitoring  

ERIC Educational Resources Information Center

|The Tenth Great Lakes Regional Meeting of the American Chemical Society met to assess current Chemical Research activity in the Great Lakes Basin, and addressed to the various aspects of the theme, Chemistry of the Great Lakes. Research areas reviewed included watershed studies, atmospheric and aquatic studies, and sediment studies. (BT)|

Delfino, Joseph J.

1976-01-01

432

Chemical Plant Security.  

National Technical Information Service (NTIS)

The potential harm to public health and the environment from a sudden release of hazardous chemicals has long concerned the U.S. Congress. This report reviews requirements that aim to reduce risks to the general public of exposure to hazardous chemicals a...

L. J. Schierow

2003-01-01

433

Identification of chemical compounds  

Microsoft Academic Search

We consider chemical identification as a process of setting up, testing, and screening of hypotheses, and review principles, techniques, and errors of identification. We also trace the relations between qualitative analysis and metrology and outline the range of known chemical compounds that are candidates for identification in general. We differentiate between methods for confirming identity and those for identifying unknowns,

Boris L. Milman

2005-01-01

434

Chemical profiles of switchgrass  

Microsoft Academic Search

Chemical analysis studies were conducted for four populations of switchgrass (Alamo, Kanlow, GA993, and GA992), Panicum virgatum L., which were partitioned into leaves, internodes, and nodes. The variations in carbohydrate compositions, lignin and extractives content, higher heating value (HHV), and the syringyl:guaiacyl ratio of switchgrass were determined. The experimental results indicated that bulk chemical profiles for the four populations of

Zhoujian Hu; Robert Sykes; Mark F. Davis; E. Charles Brummer; Arthur J. Ragauskas

2010-01-01

435

Chemical Encapsulation and Distribution.  

National Technical Information Service (NTIS)

A method is presented of coating chemicals that are used in the control of insects which protects the chemicals from biodegradation and improves their distribution in insect-containing bodies of water. A fat is mixed with an appropriate solvent, surfactan...

L. J. Goldberg

1975-01-01

436

Chemical Agent Detector Kits.  

National Technical Information Service (NTIS)

TOP 8-2-555 establishes general procedures and guidance for determining the technical performance and safety aspects of chemical agent detector kits that are designed to detect the presence of chemical agents in the atmosphere, on the surfaces of various ...

1989-01-01

437

Chemical and Physical Changes  

NSDL National Science Digital Library

The phenomenon is a chemical reaction between sugar and sulfuric acid. The demonstration (a discrepant event) compares the way sugar and water interact when combined (physical change) to the way sugar and sulfuric acid interact when combined (chemical change). In part II, students are given additional substances and changes to observe.

438

Difficult Decisions: Chemical Warfare.  

ERIC Educational Resources Information Center

|Gives the background history and chemistry of modern day chemical warfare from World War I to the present. Provides discussion questions to stimulate deeper thinking on the issue. Contains a discussion activity called "Can New Chemical Weapons Lead to Humane Warfare?" (CW)|

Slesnick, Irwin L.; Miller, John A.

1988-01-01

439

Nonadiabatic chemical reactions  

Microsoft Academic Search

A mixed quantum-classical approach where the environment is treated classically and the reactive degrees of freedom are considered to be quantum mechanical can be used to describe many chemical reactions, such as proton and electron transfer processes. We present reactive flux correlation function expressions for the rate constants of nonadiabatic chemical reactions occurring in quantum-classical systems. By means of a

Alessandro Sergi; Raymond Kapral

2005-01-01

440

Chemical Biology Consortium Agreement  

Cancer.gov

NCI_CBC v.1.2 9/2009 The National Cancer Institute’s Chemical Biology Consortium Participants Agreement Mission: The mission of the National Cancer Institute’s (“NCI”) Chemical Biology Consortium (“CBC”) is to increase the flow of early

441

Forward chemical genetic screening.  

PubMed

Chemical genetics utilizes small molecules to perturb biological processes. Unlike conventional genetics methods, which involve the alteration of genetic information mostly with lasting effects, chemical genetics allows temporary and reversible alterations of biological processes. Furthermore, it enables the alteration of biological processes in a dose-dependent manner, providing an advantage over conventional genetics.In the present chapter, the general procedures of forward chemical genetic screening are described. Forward chemical genetic screening can be performed in three steps. The first step involves the identification of small molecules that induce phenotypic or physiological changes in a biological system from a chemical library. In the second step, cellular targets that interact with the isolated chemical, which are mostly proteins, are identified. Although several methods can be applied in the second step, the most common one is affinity pull-down assay using a target protein that binds to the isolated compound. However, affinity pull-down of a target protein is a formidable barrier in forward chemical genetics. We introduced a tagged chemical library approach that significantly facilitates the identification of target proteins. The third step consists of the validation of the target protein, which should include the assessment of target specificity. This step is critical because small molecules often show pleiotropic effects due to low specificity. The specificity test may include a competition assay using cold competitors and a genetic study using mutants or transgenic lines modified for the cellular target. PMID:24057378

Choi, Hyunmo; Kim, Jun-Young; Chang, Young Tae; Nam, Hong Gil

2014-01-01

442

Combination chemical genetics  

PubMed Central

Predicting the behavior of living organisms is an enormous challenge given their vast complexity. Efforts to model biological systems require large datasets generated by physical binding experiments and perturbation studies. Genetic perturbations have proven important and are greatly facilitated by the advent of comprehensive mutant libraries in model organisms. Small-molecule chemical perturbagens provide a complementary approach, especially for systems that lack mutant libraries, and can easily probe the function of essential genes. Though single chemical or genetic perturbations provide crucial information associating individual components (for example, genes, proteins or small molecules) with pathways or phenotypes, functional relationships between pathways and modules of components are most effectively obtained from combined perturbation experiments. Here we review the current state of and discuss some future directions for ‘combination chemical genetics’, the systematic application of multiple chemical or mixed chemical and genetic perturbations, both to gain insight into biological systems and to facilitate medical discoveries.

Lehar, Joseph; Stockwell, Brent R; Giaever, Guri; Nislow, Corey

2009-01-01

443

Tortuous path chemical preconcentrator  

SciTech Connect

A non-planar, tortuous path chemical preconcentrator has a high internal surface area having a heatable sorptive coating that can be used to selectively collect and concentrate one or more chemical species of interest from a fluid stream that can be rapidly released as a concentrated plug into an analytical or microanalytical chain for separation and detection. The non-planar chemical preconcentrator comprises a sorptive support structure having a tortuous flow path. The tortuosity provides repeated twists, turns, and bends to the flow, thereby increasing the interfacial contact between sample fluid stream and the sorptive material. The tortuous path also provides more opportunities for desorption and readsorption of volatile species. Further, the thermal efficiency of the tortuous path chemical preconcentrator is comparable or superior to the prior non-planar chemical preconcentrator. Finally, the tortuosity can be varied in different directions to optimize flow rates during the adsorption and desorption phases of operation of the preconcentrator.

Manginell, Ronald P. (Albuquerque, NM); Lewis, Patrick R. (Albuquerque, NM); Adkins, Douglas R. (Albuquerque, NM); Wheeler, David R. (Albuquerque, NM); Simonson, Robert J. (Cedar Crest, NM)

2010-09-21

444

Chemical recognition software  

SciTech Connect

We have developed a capability to make real time concentration measurements of individual chemicals in a complex mixture using a multispectral laser remote sensing system. Our chemical recognition and analysis software consists of three parts: (1) a rigorous multivariate analysis package for quantitative concentration and uncertainty estimates, (2) a genetic optimizer which customizes and tailors the multivariate algorithm for a particular application, and (3) an intelligent neural net chemical filter which pre-selects from the chemical database to find the appropriate candidate chemicals for quantitative analyses by the multivariate algorithms, as well as providing a quick-look concentration estimate and consistency check. Detailed simulations using both laboratory fluorescence data and computer synthesized spectra indicate that our software can make accurate concentration estimates from complex multicomponent mixtures. even when the mixture is noisy and contaminated with unknowns.

Wagner, J.S.; Trahan, M.W.; Nelson, W.E.; Hargis, P.J. Jr.; Tisone, G.C.

1994-12-01

445

Reversible Chemical Kinetics Model  

NSDL National Science Digital Library

The Reversible Chemical Kinetics Model illustrates the time evolution of a reversible chemical reaction, from a given set of initial reactants concentration until chemical equilibrium is reached. The concentrations are plotted against time and the respective numerical values are periodically displayed at the data Table. As chemical equilibrium is attained, the concentrations become constant, the reaction quotient (Q) equalizes the equilibrium constant and Gibbs's energy change (G/RT) approaches zero. The Reversible Chemical Kinetics Model was developed using the Easy Java Simulations (EJS) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the jar file will run the program if Java is installed. You can modify this simulation if you have EJS installed by right-clicking within the map and selecting "Open Ejs Model" from the pop-up menu item.

Fernandes, Fernando S.

2012-10-20

446

Deriving Darcy's Law  

NSDL National Science Digital Library

This exercise begins with a demonstration of fluid flow through porous sediment using a constant head permeameter, with the students conducting the experiment and collecting the data. The demo is followed by a Think-Pair-Share exercise in which the question is posed to the class: "What could we change in order to increase flow through the system?" The class then works through their brainstormed list of ideas, discussing each and evaluating whether it is correct or a misconception. The students derive Darcy's Law qualitatively, based upon the results of the Think-Pair-Share exercise and discussions.

Salvage, Karen

447

Characterization of a Dopaminergic Stimulatory Factor Derived from Monoclonal Cell Lines of Striatal Origin.  

National Technical Information Service (NTIS)

A lysate of an immortalized monoclonal cell line derived from the striatum (X61) contains two types of chemically distinct factors which are capable of increasing the dopamine content of an immortalized, dopaminergic mouse mesencephalic cell line (MN9D). ...

A. Heller L. Won M. Gross

2006-01-01

448

Synthesis of methyl methacrylate from coal-derived syngas: Quarterly report, October 1-December 31, 1997.  

National Technical Information Service (NTIS)

Research Triangle Institute (RTI), Eastman Chemical Company, and Bechtel collectively are developing a novel process for the synthesis of methyl methacrylate (MMA) from coal-derived syngas that consists of three steps of synthesis of a propionate, its con...

1998-01-01

449

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

Code of Federal Regulations, 2013 CFR

...1) The chemical substance identified generically as disulfonic acid rosin amine salt of a benzidine derivative (PMN P-87-1337) is subject to reporting under this section for the significant new uses described in paragraph (a)(2) of this...

2013-07-01

450

40 CFR 454.60 - Applicability; description of manufacture of rosin-based derivatives subcategory.  

Code of Federal Regulations, 2011 CFR

...Section 454.60 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS GUM AND WOOD CHEMICALS MANUFACTURING POINT SOURCE CATEGORY Rosin-Based Derivatives Subcategory § 454.60...

2011-07-01

451

Molecularly imprinted solid-phase extraction for the screening of antihyperglycemic biguanides.  

PubMed

A new molecularly imprinted polymer (MIP) was specifically synthesized as a smart material for the recognition of metformin hydrochloride in solid-phase extraction. Particles of this MIP were packed into a stainless-steel tubing (50 mm x 0.8 mm i.d.) equipped with an exit frit. This micro-column was employed in the development of a molecularly imprinted solid-phase extraction (MISPE) method for metformin determination. The MISPE instrumentation consisted of a micrometer pump, an injector valve equipped with a 20-microl sample loop, a UV detector, and an integrator. With CH3CN as the mobile phase flowing at 0.5 ml/min, 95 +/- 2% binding could be achieved for 1200 ng of metformin from one injection of a phosphate-buffered sample solution (pH 2.5). Methanol + 3% trifluoroacetic acid was good for quantitative pulsed elution (PE) of the bound metformin. The MISPE-PE method, with UV detection at 240 nm, afforded a detection limit of 16 ng (or 0.8 microg/ml) for metformin. However, the micro-column interacted indiscriminately with phenformin with a 49 +/- 2% binding. A systematic investigation of binding selectivity was conducted with respect to sample composition (including the solvent, matrix, pH, buffer and surfactant effects). An intermediate step of differential pulsed elution used acetonitrile with 5% picric acid to remove phenformin and other structural analogues. A final pulsed elution of metformin for direct UV detection was achieved using 3% trifluoroacetic acid in methanol. PMID:14971497

Feng, Sherry Y; Lai, Edward P C; Dabek-Zlotorzynska, Ewa; Sadeghi, Susan

2004-02-20

452

Polyhexamethyl biguanide can eliminate contaminant yeasts from fuel-ethanol fermentation process  

Microsoft Academic Search

Industrial ethanol fermentation is a non-sterile process and contaminant microorganisms can lead to a decrease in industrial\\u000a productivity and significant economic loss. Nowadays, some distilleries in Northeastern Brazil deal with bacterial contamination\\u000a by decreasing must pH and adding bactericides. Alternatively, contamination can be challenged by adding a pure batch of Saccharomyces cerevisiae—a time-consuming and costly process. A better strategy might

Carolina Elsztein; João Assis Scavuzzi de Menezes; Marcos Antonio de Morais Jr

2008-01-01

453

Molecularly imprinted solid-phase extraction for the screening of antihyperglycemic biguanides  

Microsoft Academic Search

A new molecularly imprinted polymer (MIP) was specifically synthesized as a smart material for the recognition of metformin hydrochloride in solid-phase extraction. Particles of this MIP were packed into a stainless-steel tubing (50mm×0.8mm i.d.) equipped with an exit frit. This micro-column was employed in the development of a molecularly imprinted solid-phase extraction (MISPE) method for metformin determination. The MISPE instrumentation

Sherry Y Feng; Edward P. C Lai; Ewa Dabek-Zlotorzynska; Susan Sadeghi

2004-01-01

454

Derivatives of molecular electromagnetic properties using nonlocal susceptibility densities  

NASA Astrophysics Data System (ADS)

This thesis presents three analytic derivative relationships. The underlying concept of these three relationships is connecting the change of a molecular property to other well-defined molecular properties. The foundation of this work lies in nonlocal polarizability density theory. The nonlocal polarizability density characterizes the polarization at one point in a molecule due to its reaction with an electric field at another point in the molecule. In the first part, the derivative of the electronic hyperpolarizability with respect to a Cartesian nuclear coordinate is related to the nonlocal second hyperpolarizability density, the nuclear charge and the dipole propagator. The derivation uses the derivatives of the wavefunctions and operators that comprise the six- term hyperpolarizability. These derivatives, which are also derived, are substituted into the hyperpolarizability to yield a sixty-term expression. The initial result is manipulated algebraically in a nontrivial way to yield the equality. A brief review of hyper-Raman scattering theory is given. Recent applications of hyper-Raman scattering are considered. In the second part a new expression for the derivative of the polarization propagator with respect to an arbitrary coordinate is derived in terms of the quadratic polarization propagator and a sum of polarization propagators. The derivation involves calculating the derivative of a creation and annihilation operator pair with respect to an arbitrary parameter. Then the propagator derivative is calculated via the derivatives of many-electron wavefunctions. Past work calculating the derivatives of molecular properties using polarization propagator techniques is briefly reviewed. The third part concerns finding an expression for the derivative of the electronic magnetic moment with respect to nuclear momentum and its relationship to a nonlocal magnetizability density. The magnetizability density has a structure similar to the chemical shift. The relationship is found by considering the magnetic field produced by a moving nucleus as a perturbation on the electronic structure. The ground state wavefunctions are corrected to first order in perturbation theory using the nuclear magnetic field as the perturbation. The corrected wavefunctions are used to calculate the expectation value of the magnetic moment. When the derivative of this expectation value is taken with respect to nuclear momentum, its relationship with the nonlocal chemical shift density is uncovered. The result is correct when adiabatic wavefunctions that go beyond the Born- Oppenheimer approximation are used. The physical content of the equation is interpreted as a description of intramolecular magnetic response. Other possible paths to a complete susceptibility theory are considered. One path involves substitution of 4- currents into the definition of the nonlocal polarizability density. Other paths arise from an initial consideration of the relativistic Dirac equation and subsequent analysis using the Gordon decomposition and the Foldy-Wouthuysen transformation.

Tisko, Edmund Leo

455

Adipose-derived cells.  

PubMed

Heart failure is by far the most common cause of hospitalization in Western countries, with onerous economic consequences. Cell therapy holds great promise for use in tissue regeneration and is increasingly used in an effort to improve outcomes in cardiac disease. Recently it has been shown that adipose tissue, in addition to committed adipogenic, endothelial progenitor cells and pluripotent vascular progenitor cells, also contains multipotent cell types (adipose-derived stem cells, ADSCs) that, in cell culture conditions, have shown to have an impressive developmental plasticity including the ability to undergo multilineage differentiation and self-renewal. ADSCs express multiple CD marker antigens similar to those observed on MSCs and are also capable of secreting a large number of angiogenesis-related cytokines, including vascular endothelial growth factor, granulocyte/macrophage colony stimulating factor, stromal-derived factor-1alpha, and hepatocyte growth factor. Adipose tissue can be harvested in large quantities with minimal morbidity in several regions of the body and, on average, 100 ml of human adipose tissue yields about 1 x 10(6) stem cells. Studies conducted in porcine AMI models have shown a significant LV functional improvement, with no report of any potentially fatal arrhythmias. The APOLLO trial, a prospective, double blind, randomized, placebo-controlled trial currently in the recruiting phase, is a "first-in-man" study that explores the safety and feasibility of ADSC transplantation in patients with acute MI. PMID:18293895

Meliga, Emanuele; Strem, Brian M; Duckers, H J; Serruys, Patrick W

2007-01-01

456

How accurate are the nonlinear chemical Fokker-Planck and chemical Langevin equations?  

NASA Astrophysics Data System (ADS)

The chemical Fokker-Planck equation and the corresponding chemical Langevin equation are commonly used approximations of the chemical master equation. These equations are derived from an uncontrolled, second-order truncation of the Kramers-Moyal expansion of the chemical master equation and hence their accuracy remains to be clarified. We use the system-size expansion to show that chemical Fokker-Planck estimates of the mean concentrations and of the variance of the concentration fluctuations about the mean are accurate to order ?-3/2 for reaction systems which do not obey detailed balance and at least accurate to order ?-2 for systems obeying detailed balance, where ? is the characteristic size of the system. Hence, the chemical Fokker-Planck equation turns out to be more accurate than the linear-noise approximation of the chemical master equation (the linear Fokker-Planck equation) which leads to mean concentration estimates accurate to order ?-1/2 and variance estimates accurate to order ?-3/2. This higher accuracy is particularly conspicuous for chemical systems realized in small volumes such as biochemical reactions inside cells. A formula is also obtained for the approximate size of the relative errors in the concentration and variance predictions of the chemical Fokker-Planck equation, where the relative error is defined as the difference between the predictions of the chemical Fokker-Planck equation and the master equation divided by the prediction of the master equation. For dimerization and enzyme-catalyzed reactions, the errors are typically less than few percent even when the steady-state is characterized by merely few tens of molecules.

Grima, Ramon; Thomas, Philipp; Straube, Arthur V.

2011-08-01

457

Effect of organic fertilizers derived dissolved organic matter on pesticide sorption and leaching  

Microsoft Academic Search

Incorporation of organic fertilizers\\/amendments has been, and continues to be, a popular strategy for golf course turfgrass management. Dissolved organic matter (DOM) derived from these organic materials may, however, facilitate organic chemical movement through soils. A batch equilibrium technique was used to evaluate the effects of organic fertilizer-derived DOM on sorption of three organic chemicals (2,4-D, naphthalene and chlorpyrifos) in

Kun Li; Baoshan Xing; William A. Torello

2005-01-01

458

Chemical Biology is.....  

PubMed Central

Chemical Biology is a relatively new field, and as such is not yet simply or succinctly defined. It includes such a wide range of fundamental problems that this commentary could only include just a few snapshots of potential areas of interest. Overarching themes and selected recent successes and ideas in chemical biology are described to illustrate broadly the scope of the field, but should not be taken as exhaustive. The Chemical Biology Section of Chemistry Central Journal is pleased to receive manuscripts describing research into all and any aspects of the subject.

Ostler, Elizabeth L

2007-01-01

459

Chemical warfare agents.  

PubMed

Among the Weapons of Mass Destruction, chemical warfare (CW) is probably one of the most brutal created by mankind in comparison with biological and nuclear warfare. Chemical weapons are inexpensive and are relatively easy to produce, even by small terrorist groups, to create mass casualties with small quantities. The characteristics of various CW agents, general information relevant to current physical as well as medical protection methods, detection equipment available and decontamination techniques are discussed in this review article. A brief note on Chemical Weapons Convention is also provided. PMID:21829312

Ganesan, K; Raza, S K; Vijayaraghavan, R

2010-07-01

460

Chemical warfare agents  

PubMed Central

Among the Weapons of Mass Destruction, chemical warfare (CW) is probably one of the most brutal created by mankind in comparison with biological and nuclear warfare. Chemical weapons are inexpensive and are relatively easy to produce, even by small terrorist groups, to create mass casualties with small quantities. The characteristics of various CW agents, general information relevant to current physical as well as medical protection methods, detection equipment available and decontamination techniques are discussed in this review article. A brief note on Chemical Weapons Convention is also provided.

Ganesan, K.; Raza, S. K.; Vijayaraghavan, R.

2010-01-01

461

Selecting chemical treatment programs  

SciTech Connect

Many process equipment performance and reliability problems can be solved economically by the proper selection and application of chemical treatment programs. It is important to choose an experienced chemical vendor and to work closely with the vendor to develop a good chemical treatment program. This requires devoting sufficient manpower to ensure that the treatment program development is thorough and timely. After the treatment program is installed, the system operation and performance should be routinely monitored to ensure that expected benefits are achieved and unexpected problems do not develop.

Miller, J.E. (TOSCO Corp., Avon Refinery, Martinez, CA (US))

1988-09-01

462

Chemical Kinetic Models for HCCI and Diesel Combustion  

SciTech Connect

Hydrocarbon fuels for advanced combustion engines consist of complex mixtures of hundreds or even thousands of different components. These components can be grouped into a number of chemically distinct classes, consisting of n-paraffins, branched paraffins, cyclic paraffins, olefins, oxygenates, and aromatics. Biodiesel contains its own unique chemical class called methyl esters. The fractional amounts of these chemical classes are quite different in gasoline, diesel fuel, oil-sand derived fuels and bio-derived fuels, which contributes to the very different combustion characteristics of each of these types of combustion systems. The objectives of this project are: (1) Develop detailed chemical kinetic models for fuel components used in surrogate fuels for diesel and HCCI engines; (2) Develop surrogate fuel models to represent real fuels and model low temperature combustion strategies in HCCI and diesel engines that lead to low emissions and high efficiency; and (3) Characterize the role of fuel composition on low temperature combustion modes of advanced combustion engines.

Pitz, W J; Westbook, C K; Mehl, M

2008-10-30

463

Chemistry and structure of coal derived asphaltenes and preasphaltenes. Quarterly progress report, January-March 1980  

SciTech Connect

The following conclusions are drawn: (1) the aromaticity of petroleum-derived asphaltene (f/sub a/ = 0.2-0.5) is lower than that of coal-derived asphaltene (f/sub a/ = 0.6-0.7). (2) The aromatic ring systems within petroleum-derived asphaltene are much more ccondensed (peri) (H/sub aru//C/sub ar/ = 0.3-0.5) than that of coal-derived asphaltene (kata)(H/sub aru//C/sub ar/ = 0.5-0.7). (3) The substituents of the petroleum-derived asphaltenes are longer (n = 4-6) than those of coal-derived asphaltenes (n = 1). (4) The aromatic system of petroleum-derived asphaltene is extensively substituted (70 to 80%), whereas the coal-derived asphaltene is sparingly substituted (35 to 45%). (5) The molecular weight of petroleum-derived asphaltene is ca. 10 times higher than that of the coal-derived asphaltene. (6) Petroleum-derived asphaltene is less reactive to physical or chemical agents than that of coal-derived asphaltene. (7) Petroleum-derived asphaltene is more highly associated (Me = 5-7) than that of coal-derived asphaltene (Me-2-4). This will be reflected in the ease of processing. (8) Petroleum-derived asphaltene is less poplar than the coal-derived asphaltene.

Yen, T.F.

1980-01-01

464

Chemical Handler's Manual: A Guide to Chemical Control Regulations.  

National Technical Information Service (NTIS)

The Drug Enforcement Administration (DEA) is pleased to provide the Chemical Handler's Manual to assist you in understanding the provisions of the chemical control laws and their implementing regulations. These laws, including the Chemical Diversion and T...

2002-01-01

465

Inositol derivatives: evolution and functions  

Microsoft Academic Search

Current research on inositols mainly focuses on myo-inositol (Ins) derivatives in eukaryotic cells, and in particular on the many roles of Ins phospholipids and polyphosphorylated Ins derivatives. However, inositols and their derivatives are more versatile than this — they have acquired diverse functions over the course of evolution. Given the central involvement of primordial bacteria and archaea in the emergence

Robert H. Michell

2008-01-01

466

Derivative Analysis of Hyperspectral Data  

Microsoft Academic Search

With the goal of applying derivative spectral analysis to analyze high-resolution, spectrally continuous remote sensing data, several smoothing and derivative computation algorithms have been reviewed and modified to develop a set of cross-platform spectral analysis tools. Emphasis was placed on exploring different smoothing and derivative algorithms to extract spectral details from spectral data sets. A modular program was created to

Fuan Tsai; William Philpot

1998-01-01

467

Derivative spectrophotometry of cobalt alloys  

Microsoft Academic Search

The method of derivative spectrophotometry is briefly described, and derivative absorption spectra are presented for samarium, cobalt, and commercial Sm-Co alloys. It is shown that the use of derivative spectrophotometry not only improves the accuracy and selectivity of element determinations but also simplifies the analysis of alloys. Results of a statistical evaluation of the metrological characteristics of the analytical procedure

Spitsyn

1985-01-01

468

Two chemical races in Salix sachalinensis Fr. Schmidt (Salicaceae)  

Microsoft Academic Search

High-performance liquid chromatography (HPLC) profiles based on chemical constituents of the leaves of 145 individuals ofSalix sachalinensis were classified into two different patterns: one composed of flavonoids (myricetin and dihydromyricetin), and the other composed\\u000a of phenylpropanoid derivatives. This led to the conclusion that two chemical races exist inS. sachalinensis with different biosynthetic abilities to produce secondary metabolites.

Mizuo Mizuno; Masaya Kato; Munekazu Iinuma; Toshiyuki Tanaka; Arika Kimura; Hiroyoshi Ohashi; Hideki Sakai; Tadashi Kajita

1989-01-01