Novel quinazoline ring synthesis by cycloaddition of N-arylketenimines with N,N-disubstituted cyanamides.

PubMed

Shimizu, Masao; Oishi, Akihiro; Taguchi, Yoichi; Gama, Yasuo; Shibuya, Isao

2002-03-01

The reaction of N-aryl-substituted ketenimines with N,N-disubstituted cyanamides or (MeS)2C=N-CN under high pressure afforded 4-(N,N-disubstituted amino) or 4-(MeS)2C=N-substituted quinazoline derivatives, respectively. These products were formed by [4+2] cycloaddition between the aza-diene moieties of the N-arylsubstituted ketenimines and cyano groups. A 4-(unsubstituted amino)quinazoline derivative was synthesized by hydrolysis of the latter product.

Transcriptome and Metabolite Changes during Hydrogen Cyanamide-Induced Floral Bud Break in Sweet Cherry.

PubMed

Ionescu, Irina A; López-Ortega, Gregorio; Burow, Meike; Bayo-Canha, Almudena; Junge, Alexander; Gericke, Oliver; Møller, Birger L; Sánchez-Pérez, Raquel

2017-01-01

Release of bud dormancy in perennial woody plants is a temperature-dependent process and thus flowering in these species is heavily affected by climate change. The lack of cold winters in temperate growing regions often results in reduced flowering and low fruit yields. This is likely to decrease the availability of fruits and nuts of the Prunus spp. in the near future. In order to maintain high yields, it is crucial to gain detailed knowledge on the molecular mechanisms controlling the release of bud dormancy. Here, we studied these mechanisms using sweet cherry ( Prunus avium L.), a crop where the agrochemical hydrogen cyanamide (HC) is routinely used to compensate for the lack of cold winter temperatures and to induce flower opening. In this work, dormant flower buds were sprayed with hydrogen cyanamide followed by deep RNA sequencing, identifying three main expression patterns in response to HC. These transcript level results were validated by quantitative real time polymerase chain reaction and supported further by phytohormone profiling (ABA, SA, IAA, CK, ethylene, JA). Using these approaches, we identified the most up-regulated pathways: the cytokinin pathway, as well as the jasmonate and the hydrogen cyanide pathway. Our results strongly suggest an inductive effect of these metabolites in bud dormancy release and provide a stepping stone for the characterization of key genes in bud dormancy release.

Transcriptome and Metabolite Changes during Hydrogen Cyanamide-Induced Floral Bud Break in Sweet Cherry

PubMed Central

Ionescu, Irina A.; López-Ortega, Gregorio; Burow, Meike; Bayo-Canha, Almudena; Junge, Alexander; Gericke, Oliver; Møller, Birger L.; Sánchez-Pérez, Raquel

2017-01-01

Release of bud dormancy in perennial woody plants is a temperature-dependent process and thus flowering in these species is heavily affected by climate change. The lack of cold winters in temperate growing regions often results in reduced flowering and low fruit yields. This is likely to decrease the availability of fruits and nuts of the Prunus spp. in the near future. In order to maintain high yields, it is crucial to gain detailed knowledge on the molecular mechanisms controlling the release of bud dormancy. Here, we studied these mechanisms using sweet cherry (Prunus avium L.), a crop where the agrochemical hydrogen cyanamide (HC) is routinely used to compensate for the lack of cold winter temperatures and to induce flower opening. In this work, dormant flower buds were sprayed with hydrogen cyanamide followed by deep RNA sequencing, identifying three main expression patterns in response to HC. These transcript level results were validated by quantitative real time polymerase chain reaction and supported further by phytohormone profiling (ABA, SA, IAA, CK, ethylene, JA). Using these approaches, we identified the most up-regulated pathways: the cytokinin pathway, as well as the jasmonate and the hydrogen cyanide pathway. Our results strongly suggest an inductive effect of these metabolites in bud dormancy release and provide a stepping stone for the characterization of key genes in bud dormancy release. PMID:28769948

Non-precious metal catalysts prepared from precursors comprising cyanamide and polyaniline

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chung, Hoon Taek; Zelenay, Piotr

A catalyst for oxygen reduction reaction (ORR) for a fuel cell was prepared by pyrolyzing a mixture of polyaniline, cyanamide, carbon black, and a non-precious metal salt under an inert atmosphere. The pyrolyzed product was treated to remove acid soluble components and then pyrolyzed again. The resulting powder was used to prepare a cathode for a membrane electrode assembly that was used in a fuel cell. When iron(III) chloride was used as the salt, the resulting catalyst was porous with a web-shaped structure. It displayed a maximum power density of 0.79 W/cm at 0.4 V in H.sub.2/O.sub.2 at 1.0 barmore » back pressure.« less

Formation of Cyanamide-Glyoxal Oligomers in Aqueous Environments Relevant to Primeval and Astrochemical Scenarios: A Spectroscopic and Theoretical Study.

PubMed

Lavado, Nieves; García de la Concepción, Juan; Babiano, Reyes; Cintas, Pedro

2018-03-15

The condensation of cyanamide and glyoxal, two well-known prebiotic monomers, in an aqueous phase has been investigated in great detail, demonstrating the formation of oligomeric species of varied structure, though consistent with generalizable patterns. This chemistry involving structurally simple substances also illustrates the possibility of building molecular complexity under prebiotically plausible conditions, not only on Earth, but also in extraterrestrial scenarios. We show that cyanamide-glyoxal reactions in water lead to mixtures comprising both acyclic and cyclic fragments, largely based on fused five- and six-membered rings, which can be predicted by computation. Remarkably, such a mixture could be identified using high-resolution electrospray ionization (ESI) mass spectrometry and spectroscopic methods. A few mechanistic pathways can be postulated, most involving the intermediacy of glyoxal cyanoimine and further chain growth, thus increasing the diversity of the observed products. This rationale is supported by theoretical analyses with clear-cut identification of all of the stationary points and transition-state structures. The properties and structural differences of oligomers obtained under thermodynamic conditions in water as opposed to those isolated by precipitation from organic media are also discussed. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Synthesis of new structurally related cyanamide compounds LiM(CN{sub 2}){sub 2} where M is Al{sup 3+}, In{sup 3+} or Yb{sup 3+}

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kubus, Mariusz, E-mail: mariusz.kubus@anorg.uni-tuebingen.de; Heinicke, Robert; Ströbele, Markus

2015-02-15

Highlights: • New cyanamide compounds LiM(CN{sub 2}){sub 2} where M is Al{sup 3+}, In{sup 3+} or Yb{sup 3+}. • New luminescent material LiIn(CN{sub 2}){sub 2}:Tb{sup 3+}. • Reduction in efficiency of luminescence with temperature increase. - Abstract: New ternary cyanamide compounds isostructural to LiY(CN{sub 2}){sub 2} were obtained by solid state metathesis reaction. The crystal structure of LiAl(CN{sub 2}){sub 2} was determined by single crystal X-ray diffraction, the structures of LiIn(CN{sub 2}){sub 2} and LiYb(CN{sub 2}){sub 2} were solved from X-ray powder diffraction data. Photoluminescence properties of Tb{sup 3+}-doped LiIn(CN{sub 2}){sub 2} are reported too.

Low energy electron attachment to cyanamide (NH{sub 2}CN)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tanzer, Katrin; Denifl, Stephan, E-mail: Andrzej.Pelc@poczta.umcs.lublin.pl, E-mail: Stephan.Denifl@uibk.ac.at; Pelc, Andrzej, E-mail: Andrzej.Pelc@poczta.umcs.lublin.pl, E-mail: Stephan.Denifl@uibk.ac.at

Cyanamide (NH{sub 2}CN) is a molecule relevant for interstellar chemistry and the chemical evolution of life. In the present investigation, dissociative electron attachment to NH{sub 2}CN has been studied in a crossed electron–molecular beams experiment in the electron energy range from about 0 eV to 14 eV. The following anionic species were detected: NHCN{sup −}, NCN{sup −}, CN{sup −}, NH{sub 2}{sup −}, NH{sup −}, and CH{sub 2}{sup −}. The anion formation proceeds within two broad electron energy regions, one between about 0.5 and 4.5 eV and a second between 4.5 and 12 eV. A discussion of possible reaction channels formore » all measured negative ions is provided. The experimental results are compared with calculations of the thermochemical thresholds of the anions observed. For the dehydrogenated parent anion, we explain the deviation between the experimental appearance energy of the anion with the calculated corresponding reaction threshold by electron attachment to the isomeric form of NH{sub 2}CN—carbodiimide.« less

Prebiotic-Like Condensations of Cyanamide and Glyoxal: Revisiting Intractable Biotars.

PubMed

Lavado, Nieves; Escamilla, Juan Carlos; Ávalos, Martín; Babiano, Reyes; Cintas, Pedro; Jiménez, José Luis; Palacios, Juan Carlos

2016-09-12

We report a detailed investigation into the nature of products that are generated by the reactions of cyanamide and glyoxal, two small molecules of astrochemical and prebiotic significance, under different experimental conditions. The experimental data suggest that the formation of oligomeric structures is related in part to the formation of insoluble tholins in the presence of oxygen-containing molecules. Although oligomerization proceeds well in water, product isolation turned out to be impractical. Instead, solid precipitates were obtained easily in acetone. Crude mixtures have been thoroughly scrutinized by spectroscopic methods, in particular NMR and mass spectroscopy (ESI mode), which are all consistent with the generation of a few functional groups that are embedded into regular chains of five- and six-membered rings, thereby pointing to a supramolecular organization. Three different models of cross-condensation and chain growth are suggested. These synthetic explorations provide further insights into the formation of complex organic matter in interstellar scenarios and extraterrestrial bodies that might have played a pivotal role in chemical evolution. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Hydrogen cyanamide breaks grapevine bud dormancy in the summer through transient activation of gene expression and accumulation of reactive oxygen and nitrogen species.

PubMed

Sudawan, Boonyawat; Chang, Chih-Sheng; Chao, Hsiu-Fung; Ku, Maurice S B; Yen, Yung-Fu

2016-09-15

Hydrogen cyanamide (HC) and pruning (P) have frequently been used to break dormancy in grapevine floral buds. However, the exact underlying mechanism remains elusive. This study aimed to address the early mode of action of these treatments on accumulation of reactive oxygen species (ROS) and reactive nitrogen species (RNS) and expression of related genes in the dormancy breaking buds of grapevine in the summer. The budbreak rates induced by pruning (P), hydrogen cyanamide (HC), pruning plus hydrogen cyanamide (PHC) and water (control) after 8 days were 33, 53, 95, and 0 %, respectively. Clearly, HC was more effective in stimulating grapevine budbreak and P further enhanced its potency. In situ staining of longitudinal bud sections after 12 h of treatments detected high levels of ROS and nitric oxide (NO) accumulated in the buds treated with PHC, compared with HC or P alone. The amounts of ROS and NO accumulated were highly correlated with the rates of budbreak among these treatments, highlighting the importance of a rapid, transient accumulation of sublethal levels of ROS and RNS in dormancy breaking. Microarray analysis revealed specific alterations in gene expression in dormancy breaking buds induced by P, HC and PHC after 24 h of treatment. Relative to control, PHC altered the expression of the largest number of genes, while P affected the expression of the least number of genes. PHC also exerted a greater intensity in transcriptional activation of these genes. Gene ontology (GO) analysis suggests that alteration in expression of ROS related genes is the major factor responsible for budbreak. qRT-PCR analysis revealed the transient expression dynamics of 12 specific genes related to ROS generation and scavenge during the 48 h treatment with PHC. Our results suggest that rapid accumulation of ROS and NO at early stage is important for dormancy release in grapevine in the summer, and the identification of the commonly expressed specific genes among the

Rotation and rotation-vibration spectroscopy of the 0+-0- inversion doublet in deuterated cyanamide.

PubMed

Kisiel, Zbigniew; Kraśnicki, Adam; Jabs, Wolfgang; Herbst, Eric; Winnewisser, Brenda P; Winnewisser, Manfred

2013-10-03

The pure rotation spectrum of deuterated cyanamide was recorded at frequencies from 118 to 649 GHz, which was complemented by measurement of its high-resolution rotation-vibration spectrum at 8-350 cm(-1). For D2NCN the analysis revealed considerable perturbations between the lowest Ka rotational energy levels in the 0(+) and 0(-) substates of the lowest inversion doublet. The final data set for D2NCN exceeded 3000 measured transitions and was successfully fitted with a Hamiltonian accounting for the 0(+) ↔ 0(-) coupling. A smaller data set, consisting only of pure rotation and rotation-vibration lines observed with microwave techniques was obtained for HDNCN, and additional transitions of this type were also measured for H2NCN. The spectroscopic data for all three isotopic species were fitted with a unified, robust Hamiltonian allowing confident prediction of spectra well into the terahertz frequency region, which is of interest to contemporary radioastronomy. The isotopic dependence of the determined inversion splitting, ΔE = 16.4964789(8), 32.089173(3), and 49.567770(6) cm(-1), for D2NCN, HDNCN, and H2NCN, respectively, is found to be in good agreement with estimates from a simple reduced quartic-quadratic double minimum potential.

Effect of calcium cyanamide, ammonium bicarbonate and lime mixture, and ammonia water on survival of Ralstonia solanacearum and microbial community

PubMed Central

Liu, Lijuan; Sun, Chengliang; Liu, Xingxing; He, Xiaolin; Liu, Miao; Wu, Hao; Tang, Caixian; Jin, Chongwei; Zhang, Yongsong

2016-01-01

The inorganic nitrogenous amendments calcium cyanamide (CC), ammonia water (AW), and a mixture of ammonium bicarbonate with lime (A+L) are popularly used as fumigants to control soil-borne disease in China. However, it is unclear which of these fumigants is more effective in controlling R. solanacearum. This present study compared the efficiencies of the three nitrogenous amendments listed above at four nitrogen levels in suppressing the survival of R. solanacearum in soil. The CC showed the best ability to suppress R. solanacearum due to its highest capacity to increase soil and NO2− contents and pH. However, AW was more suitable to controlling bacterial wilt caused by R. solanacearum because it had a lower cost and its application rate of 0.25 g N kg−1 soil could effectively suppress the survival of R. solanacearum. Additionally, soil microbial activity and community populations were restored to their initial state four weeks after the application of each fumigant, indicating that the three fumigants had few detrimental impacts on soil microbial activity and community structure with an exception of the suppression of R. solanacearum. The present study provides guidance for the selection of a suitable alkaline nitrogenous amendment and its application rate in controlling bacterial wilt. PMID:26738601

Effect of calcium cyanamide, ammonium bicarbonate and lime mixture, and ammonia water on survival of Ralstonia solanacearum and microbial community

NASA Astrophysics Data System (ADS)

Liu, Lijuan; Sun, Chengliang; Liu, Xingxing; He, Xiaolin; Liu, Miao; Wu, Hao; Tang, Caixian; Jin, Chongwei; Zhang, Yongsong

2016-01-01

The inorganic nitrogenous amendments calcium cyanamide (CC), ammonia water (AW), and a mixture of ammonium bicarbonate with lime (A+L) are popularly used as fumigants to control soil-borne disease in China. However, it is unclear which of these fumigants is more effective in controlling R. solanacearum. This present study compared the efficiencies of the three nitrogenous amendments listed above at four nitrogen levels in suppressing the survival of R. solanacearum in soil. The CC showed the best ability to suppress R. solanacearum due to its highest capacity to increase soil and NO2- contents and pH. However, AW was more suitable to controlling bacterial wilt caused by R. solanacearum because it had a lower cost and its application rate of 0.25 g N kg-1 soil could effectively suppress the survival of R. solanacearum. Additionally, soil microbial activity and community populations were restored to their initial state four weeks after the application of each fumigant, indicating that the three fumigants had few detrimental impacts on soil microbial activity and community structure with an exception of the suppression of R. solanacearum. The present study provides guidance for the selection of a suitable alkaline nitrogenous amendment and its application rate in controlling bacterial wilt.

Effect of calcium cyanamide, ammonium bicarbonate and lime mixture, and ammonia water on survival of Ralstonia solanacearum and microbial community.

PubMed

Liu, Lijuan; Sun, Chengliang; Liu, Xingxing; He, Xiaolin; Liu, Miao; Wu, Hao; Tang, Caixian; Jin, Chongwei; Zhang, Yongsong

2016-01-07

The inorganic nitrogenous amendments calcium cyanamide (CC), ammonia water (AW), and a mixture of ammonium bicarbonate with lime (A+L) are popularly used as fumigants to control soil-borne disease in China. However, it is unclear which of these fumigants is more effective in controlling R. solanacearum. This present study compared the efficiencies of the three nitrogenous amendments listed above at four nitrogen levels in suppressing the survival of R. solanacearum in soil. The CC showed the best ability to suppress R. solanacearum due to its highest capacity to increase soil and NO2(-) contents and pH. However, AW was more suitable to controlling bacterial wilt caused by R. solanacearum because it had a lower cost and its application rate of 0.25 g N kg(-1) soil could effectively suppress the survival of R. solanacearum. Additionally, soil microbial activity and community populations were restored to their initial state four weeks after the application of each fumigant, indicating that the three fumigants had few detrimental impacts on soil microbial activity and community structure with an exception of the suppression of R. solanacearum. The present study provides guidance for the selection of a suitable alkaline nitrogenous amendment and its application rate in controlling bacterial wilt.

Phytotoxic cyanamide affects maize (Zea mays) root growth and root tip function: from structure to gene expression.

PubMed

Soltys, Dorota; Rudzińska-Langwald, Anna; Kurek, Wojciech; Szajko, Katarzyna; Sliwinska, Elwira; Bogatek, Renata; Gniazdowska, Agnieszka

2014-05-01

Cyanamide (CA) is a phytotoxic compound produced by four Fabaceae species: hairy vetch, bird vetch, purple vetch and black locust. Its toxicity is due to complex activity that involves the modification of both cellular structures and physiological processes. To date, CA has been investigated mainly in dicot plants. The goal of this study was to investigate the effects of CA in the restriction of the root growth of maize (Zea mays), representing the monocot species. CA (3mM) reduced the number of border cells in the root tips of maize seedlings and degraded their protoplasts. However, CA did not induce any significant changes in the organelle structure of other root cells, apart from increased vacuolization. CA toxicity was also demonstrated by its effect on cell cycle activity, endoreduplication intensity, and modifications of cyclins CycA2, CycD2, and histone HisH3 gene expression. In contrast, the arrangement of microtubules was not altered by CA. Treatment of maize seedlings with CA did not completely arrest mitotic activity, although the frequency of dividing cells was reduced. Furthermore, prolonged CA treatment increased the proportion of endopolyploid cells in the root tip. Cytological malformations were accompanied by an induction of oxidative stress in root cells, which manifested as enhanced accumulation of H2O2. Exposure of maize seedlings to CA resulted in an increased concentration of auxin and stimulated ethylene emission. Taken together, these findings suggested that the inhibition of root growth by CA may be a consequence of stress-induced morphogenic responses. Copyright © 2014. Published by Elsevier GmbH.

Characterization of Thick Glass Reinforced Composites

DTIC Science & Technology

1992-07-01

24 ounces per square yard. The matrices were different polyester resin systems from American Cyanamid and Owens Corning . Specimen thicknesses ranged...fab- ricated similar size plates using the American Cyanamid resin. The Owens Corning plates con- tained 53% volume fraction fiber while the American...thicknesses for the Owens Corning and four for the American Cyanamid. Specimens were loaded in three point bending at a displacement rate that was changed

Developmental lead exposure induces opposite effects on ethanol intake and locomotion in response to central vs. systemic cyanamide administration.

PubMed

Mattalloni, Mara Soledad; Deza-Ponzio, Romina; Albrecht, Paula Alejandra; Cancela, Liliana Marina; Virgolini, Miriam Beatriz

2017-02-01

Lead (Pb) is a developmental neurotoxicant that elicits differential responses to drugs of abuse. Particularly, ethanol consumption has been demonstrated to be increased as a consequence of environmental Pb exposure, with catalase (CAT) and brain acetaldehyde (ACD, the first metabolite of ethanol) playing a role. The present study sought to interfere with ethanol metabolism by inhibiting ALDH2 (mitochondrial aldehyde dehydrogenase) activity in both liver and brain from control and Pb-exposed rats as a strategy to accumulate ACD, a substance that plays a major role in the drug's reinforcing and/or aversive effects. To evaluate the impact on a 2-h chronic voluntary ethanol intake test, developmentally Pb-exposed and control rats were administered with cyanamide (CY, an ALDH inhibitor) either systemically or intracerebroventricularly (i.c.v.) on the last 4 sessions of the experiment. Furthermore, on the last session and after locomotor activity was assessed, all animals were sacrificed to obtain brain and liver samples for ALDH2 and CAT activity determination. Systemic CY administration reduced the elevated ethanol intake already reported in the Pb-exposed animals (but not in the controls) accompanied by liver (but not brain) ALDH2 inactivation. On the other hand, a 0.3 mg i.c.v. CY administration enhanced both ethanol intake and locomotor activity accompanied by brain ALDH2 inactivation in control animals, while an increase in ethanol consumption was also observed in the Pb-exposed group, although in the absence of brain ALDH2 blockade. No changes were observed in CAT activity as a consequence of CY administration. These results support the participation of liver and brain ACD in ethanol intake and locomotor activity, responses that are modulated by developmental Pb exposure. Copyright © 2016 Elsevier Inc. All rights reserved.

A Review of the Literature and of Work Done in A.R.D and C.R.D.D. on Picrite and its Intermediates with a View to Finding a Cheap and Economical Process

DTIC Science & Technology

1947-05-01

dehydrating agents are finely divided nickel aluminium or phosphorous pentoxide. AI2O? or MCO2 Bay be present, ^°°) (c) By the hydrolysis of cyanurea...to form guanidino nitrate which is then dehydrated to nitroguanidine, the equation being as follows:- " CaO + C02 CaC2 + CO CaCN2 + C (4...cyanamide. The presence of water increases the yield of cyanamide. Iron is avoided as it I; causes decomposition but hydrogen sulphide or carbon

Role of acetaldehyde in ethanol-induced conditioned taste aversion in rats.

PubMed

Escarabajal, M Dolores; De Witte, Philippe; Quertemont, Etienne

2003-05-01

In spite of many recent studies on the effects of acetaldehyde, it is still unclear whether acetaldehyde mediates the reinforcing and/or aversive effects of ethanol. The present study reexamined the role of acetaldehyde in ethanol-induced conditioned taste aversion (CTA). A first experiment compared ethanol- and acetaldehyde-induced CTA. In a second experiment, cyanamide, an aldehyde dehydrogenase inhibitor, was administered before conditioning with either ethanol or acetaldehyde to investigate the effects of acetaldehyde accumulation. A classic CTA protocol was used to associate the taste of a saccharin solution with either ethanol or acetaldehyde injections. In experiment 1, saccharin consumption was followed by injections of either ethanol (0, 0.5, 1.0, 1.5 or 2.0 g/kg) or acetaldehyde (0, 100, 170 or 300 mg/kg). In experiment 2, the rats were pretreated with either saline or cyanamide (25 mg/kg) before conditioning with either ethanol or acetaldehyde. Both ethanol and acetaldehyde induced significant CTA. However, ethanol produced a very strong CTA relative to acetaldehyde that induced only a weak CTA even at toxic doses. Cyanamide pretreatments significantly potentiated ethanol- but not acetaldehyde-induced CTA. The present results indicate that ethanol-induced CTA does not result from brain acetaldehyde effects. In contrast, it is suggested that the reinforcing effects of brain acetaldehyde might actually reduce ethanol-induced CTA. Our results also suggest that the inhibition of brain catalase activity may contribute to the potentiating effects of cyanamide on ethanol-induced CTA.

Copper-Catalyzed Domino Three-Component Approach for the Assembly of 2-Aminated Benzimidazoles and Quinazolines.

PubMed

Tran, Lam Quang; Li, Jihui; Neuville, Luc

2015-06-19

A copper-promoted three-component synthesis of 2-aminobenzimidazoles (1) or of 2-aminoquinazolines (2) involving cyanamides, arylboronic acids, and amines has been developed. The operationally simple oxidative process, performed in the presence of K2CO3, a catalytic amount of CuCl2·2H2O, 2,2'-bipyridine, and an O2 atmosphere (1 atm), allows the rapid assembly of either benzimidazoles or quinazolines starting from aryl- or benzyl-substituted cyanamides, respectively. In this process, the copper promotes the formation of three bonds, two C-N bonds, and an additional bond resulting from C-H functionalization event.

The structure of carbodiimide, HNCNH

NASA Astrophysics Data System (ADS)

Jabs, Wolfgang; Winnewisser, Manfred; Belov, Sergei P.; Lewen, Frank; Maiwald, Frank; Winnewisser, Gisbert

An experimentally determined rs -type structure of HNCNH is reported: rNH = 1.0074 A, rCN = 1.2242 A, /HNC = 118.63, /NCN = 170.63, /HN NH = 88.99 . The number of digits quoted allow for errors with two significant figures. In order to obtain these values we recorded rotational-torsional spectra of HN13CNH, H15NC15NH and DNCND, by using isotopically enriched cyanamide. A chemical equilibrium exists between carbodiimide, HNCNH, and the more stable isomer cyanamide, H2NCN, which strongly favours cyanamide (approximately 1:115 at 110 oC). The expensive C- and N-substituted isotopomers could only be investigated in the millimetre wave region, while for DNCND the far infrared spectrum between 10-350 cm-1 was also recorded. Rotational constants of the three isotopomers, as well as of the parent species, were determined by fitting the assigned spectral transitions to the Watson Hamiltonian in S reduction. Using fitting programs written by Schwendeman and Rudolph, r0, rs and rrho m structures of HNCNH were derived. The experimentally determined structural parameters are compared with an ab initio re structure.

Formation of urea and guanidine by irradiation of ammonium cyanide.

NASA Technical Reports Server (NTRS)

Lohrmann, R.

1972-01-01

Aqueous solutions of ammonium cyanide yield urea, cyanamide and guanidine when exposed to sunlight or an unfiltered 254 nm ultraviolet source. The prebiotic significance of these results is discussed.

75 FR 34448 - Proposed CERCLA Administrative Cost Recovery Settlement; Great Lakes Container Corporation...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-06-17

... Cyanamid Company); Hubbard Hall, Inc.; Invesys, Inc. on behalf of Elmwood Sensors, Inc.; Chevron..., subsidiaries and divisions; BP Products North America, Inc.; Eastern Color & Chemical Company. Dated: June 3...

Synthesis ofN-(2-chloro-5-methylthiophenyl)-N'-(3-methyl-thiophenyl)-N'-[3H3]methylguanidine, l brace [3H3]CNS-5161 r brace

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gibbs, Andrew R.; Morimoto, Hiromi; VanBrocklin, Henry F.

2001-09-28

The preparation of the title compound, [{sup 3}H{sub 3}]CNS-5161, was accomplished in three steps starting with the production of [{sup 3}H{sub 3}]iodomethane (CT{sub 3}I). The intermediate N-[{sup 3}H{sub 3}]methyl-3-(thiomethylphenyl)cyanamide was prepared in 77% yield by the addition of CT{sub 3}I to 3-(thiomethylphenyl)cyanamide, previously treated with sodium hydride. Reaction of this tritiated intermediate with 2-chloro-5-thiomethylaniline hydrochloride formed the guanidine compound [{sup 3}H{sub 3}]CNS-5161. Purification by HPLC gave the desired labeled product in an overall yield of 9% with greater than 96% radiochemical purity and a final specific activity of 66 Ci mmol{sup -1}.

Evaluation of Toxic Air Emissions

DTIC Science & Technology

1995-06-01

108394 106445 98828 94757 3547044 334883 Calcium Cyanamide Caprolactam Captan Carbaryl Carbon disulfide Carbon Tetrachloride Carbonyl sulfide Catechol...Phosphorus Phthalic anhydride Polychlorinated biphenyls (Aroclors) 1,3-Propane sultone beta-Propiolactone Propionaldehyde Propoxur (Baygon) Propylene

Synthesis of the coenzymes adenosine diphosphate glucose, guanosine diphosphate glucose, and cytidine diphosphoethanolamine under primitive Earth conditions

NASA Technical Reports Server (NTRS)

Mar, A.; Oro, J.

1991-01-01

The nonenzymatic synthesis of the coenzymes adenosine diphosphate glucose (ADPG), guanosine diphosphate glucose (GDPG), and cytidine diphosphoethanolamine (CDP-ethanolamine) has been carried out under conditions considered to have been prevalent on the early Earth. The production of these compounds was performed by allowing simple precursor molecules to react under aqueous solutions, at moderate temperatures and short periods of time, with mediation by cyanamide or urea. These two condensing agents are considered to have been present in significant amounts on the primitive Earth and have been previously used in the nonenzymatic synthesis of several other important biochemical compounds. In our experiments, ADPG was obtained by heating glucose-1-phosphate (G1P) and ATP in the presence of cyanamide for 24 h at 70 degrees C. The reaction of G1P and GTP under the same conditions yielded GDPG. The cyanamide-mediated production of CDP-ethanolamine was carried out by reacting a mixture of ethanolamine phosphate and CTP for 24 h at 70 degrees C. The separation and identification of the reaction products was carried out by paper chromatography, thin-layer chromatography, high performance thin-layer chromatography, high performance liquid chromatography, both normal and reverse-phase, UV spectroscopy, enzymatic assays, and acid hydrolysis. Due to the mild conditions employed, and to the relative ease of these reactions, these studies offer a simple attractive system for the nonenzymatic synthesis of phosphorylated high-energy metabolic intermediates under conditions considered to have been prevalent on the ancient Earth.

Hazardous Waste Cleanup: Wyeth Holdings Corporation in Princeton Junction, New Jersey

EPA Pesticide Factsheets

BASF, formerly American Cyanamid Corporation (ACC) Agricultural Division, is a 683 acre site, located at the intersection of Quakerbridge Rd and US Route 1 in Princeton Junction, NJ. BASF bought the operations of ACC Agricultural Division from American

PERSPECTIVE VIEW LOOKING SOUTHWEST AT THE EAST SIDE OF THE ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

PERSPECTIVE VIEW LOOKING SOUTHWEST AT THE EAST SIDE OF THE CYANAMIDE (L-N) OVEN BUILDING. PIECES OF A DISASSEMBLED RAIL CAR IN FOREGROUND. - United States Nitrate Plant No. 2, Reservation Road, Muscle Shoals, Muscle Shoals, Colbert County, AL

The National Shipbuilding Research Program. Historical Overview of Efforts to Reduce VOC Emissions Through Coating Reformulations and Analysis of VOC vs HAP Content in Marine Coatings

DTIC Science & Technology

1995-05-01

79118 532274 108907 510156 67663 107302 126998 1319773 95287 108394 106445 1,3-Butadiene Calcium Cyanamide Caprolactam Captan Carbaryl Carbon disulfide...96093 1746016 79345 127184 7550450 108883 95807 584849 95534 8001352 120821 79005 79016 Propionaldehyde Propoxur (Baygon) Propylene dichloride (1,2

Tolerance to disulfiram induced by chronic alcohol intake in the rat.

PubMed

Tampier, Lutske; Quintanilla, María Elena; Israel, Yedy

2008-06-01

Disulfiram, an inhibitor of aldehyde dehydrogenase used in the treatment of alcoholism, is an effective medication when its intake is supervised by a third person. However, its therapeutic efficacy varies widely, in part due to the fact that disulfiram is a pro-drug that requires its transformation into an active form and because it shows a wide range of secondary effects which often prevent the use of doses that ensure full therapeutic effectiveness. In this preclinical study in rats we report the development of tolerance to disulfiram induced by the chronic ingestion of ethanol, an additional source of variation for the actions of disulfiram with possible therapeutic significance, We also addresses the likely mechanism of this effect. Wistar-derived rats bred for generations as high ethanol drinkers (UChB) were trained for either 3 days (Group A) or 30 days (Group B) to choose between ethanol (10% v/v) or water, which were freely available from 2 bottles on a 24-hour basis. Subsequently, animals in both groups were administered disulfiram or cyanamide (another inhibitor of aldehyde dehydrogenase) and ethanol intake in this free choice paradigm was determined. Animals were also administered a standard dose of 1 g ethanol/kg (i.p) and arterial blood acetaldehyde was measured. Disulfiram (12.5 and 25 mg/kg) and cyanamide (10 mg/kg) markedly inhibited ethanol intake (up to 60 to 70%) in animals that had ethanol access for only 3 days (Group A). However both drugs were inactive in inhibiting ethanol intake in animals that had consumed ethanol for 30 days (Group B). Following the injection of 1 g ethanol/kg, arterial blood acetaldehyde levels reached levels of 150 and 300 microM for disulfiram and cyanamide respectively, values which were virtually identical regardless of the length of prior ethanol intake of the animals. Chronic ethanol intake in high-drinker rats leads to marked tolerance to the aversive effects of disulfiram and cyanamide on ethanol intake despite

40 CFR 62.2601 - Identification of sources.

Code of Federal Regulations, 2012 CFR

2012-07-01

... Section 62.2601 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS...: (1) American Cyanamid Company in Savannah, and (2) Cities Service Company in Augusta. (b) Oleum plant of Cities Service Company in Augusta. (c) There are no bound sulfur feedstock plants. Fluoride...

40 CFR 62.2601 - Identification of sources.

Code of Federal Regulations, 2010 CFR

2010-07-01

... Section 62.2601 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS...: (1) American Cyanamid Company in Savannah, and (2) Cities Service Company in Augusta. (b) Oleum plant of Cities Service Company in Augusta. (c) There are no bound sulfur feedstock plants. Fluoride...

40 CFR 62.2601 - Identification of sources.

Code of Federal Regulations, 2011 CFR

2011-07-01

... Section 62.2601 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS...: (1) American Cyanamid Company in Savannah, and (2) Cities Service Company in Augusta. (b) Oleum plant of Cities Service Company in Augusta. (c) There are no bound sulfur feedstock plants. Fluoride...

40 CFR 62.2601 - Identification of sources.

Code of Federal Regulations, 2013 CFR

2013-07-01

... Section 62.2601 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS...: (1) American Cyanamid Company in Savannah, and (2) Cities Service Company in Augusta. (b) Oleum plant of Cities Service Company in Augusta. (c) There are no bound sulfur feedstock plants. Fluoride...

40 CFR 62.2601 - Identification of sources.

Code of Federal Regulations, 2014 CFR

2014-07-01

... Section 62.2601 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS...: (1) American Cyanamid Company in Savannah, and (2) Cities Service Company in Augusta. (b) Oleum plant of Cities Service Company in Augusta. (c) There are no bound sulfur feedstock plants. Fluoride...

PSD Reconstruction Requirements American Cyanamid Company

EPA Pesticide Factsheets

This document may be of assistance in applying the New Source Review (NSR) air permitting regulations including the Prevention of Significant Deterioration (PSD) requirements. This document is part of the NSR Policy and Guidance Database. Some documents in the database are a scanned or retyped version of a paper photocopy of the original. Although we have taken considerable effort to quality assure the documents, some may contain typographical errors. Contact the office that issued the document if you need a copy of the original.

Plant's sterilization rule for fertile women cited.

PubMed

1979-01-01

The American Cyanamid Corporation has been cited by the Occupational Safety and Health Administration (OSHA) for violating federal law by requiring female employees of childbearing age to be sterilized in order to continue working in areas of the plant where they would be exposed to high levels of airborne lead. High levels of airborne lead can cause damage to workers' reproductive systems and be responsible for birth defects in fetuses. The OSHA charged that American Cyanamid's policy constituted a "willful violation" of the 1970 Occupational Safety and Health Act. The Act requires employers to provide employment that is free from recognized hazards likely to cause death or physical harm. According to OSHA, the Act does not allow an employer to eliminate the hazard by compelling employees to choose between losing their jobs and undergoing sterilization. The reproductive health of workers is considered a valid part of OSHA's regulatory concern. The citation, which carries a $10,000 fine, grew out of a complaint that was filed by the Oil, Chemical and Atomic Workers Union on behalf of 5 female workers working in the lead pigment division of the company's Willow Island, West Virginia plant. The 5 employees alleged that they had themselves sterilized to avoid being transferred to other and possibly lower paying janitorial jobs or losing thier jobs completely. The company is appealing the citation. The union has also filed a complaint with the Equal Employment Opportunity Commission charging American Cyanamid with sex discrimination, since only the women workers are at risk of being transferred to lower paying jobs.

Ionic Liquid as a Solvent and Catalyst for Acylation of Maltodextrin

USDA-ARS?s Scientific Manuscript database

Catalyst-free esterification of maltodextrin was carried out in ionic liquid. Stearate esters of maltodextrin were obtained in various degree of substitution (DS) when vinyl stearate or stearic acid was heated with maltodextrin in ionic liquid, 1-butyl-3-methylimidazolium cyanamide (bmim[dca]). Re...

Improving the Durability of Methanol Oxidation Reaction Electro-Catalysts Through the Modification of Carbon Architectures

DTIC Science & Technology

2014-01-01

zeolite template was used in conjunction with liquid cyanamide to form a carbon nitride structure with a better 2D mesoporous hexagonal framework, resulting...the core. Both hybrid inorganic–organic polymer networks and 139 zeolitic inorganic–organic polymer electrolyte materials were used to impregnate an

Synthesis of phosphatidylcholine under possible primitive earth conditions

NASA Technical Reports Server (NTRS)

Rao, M.; Eichberg, J.; Oro, J.

1982-01-01

Using a primitive earth evaporating pond model, the synthesis of phosphatidylcholine was accomplished when a reaction mixture of choline chloride and disodium phosphatidate, in the presence of cyanamide and traces of acid, was evaporated and heated at temperatures ranging from 25 to 100 C for 7 hours. Optimum yields of about 15% were obtained at 80 C. Phosphatidylcholine was identified by chromatographic, chemical and enzymatic degradation methods. On enzymatic hydrolysis with phospholipase A2 and phospholipase C, lysophosphatidylcholine and phosphorylcholine were formed, respectively. Alkaline hydrolysis gave glycerophosphorylcholine. The synthesis of phosphatidylcholine as the major compound was accompanied by the formation of lysophosphatidylcholine in smaller amounts. Cyanamide was found to be essential for the formation of phosphatidylcholine, and only traces of HCl, of the order of that required to convert the disodium phosphatidate to free phosphatidic acid were found necessary for the synthesis. This work suggests that phosphatidylcholine, which is an essential component of most biological membranes, could have been synthesized on the primitive earth.

Environmental Compliance Assessment System (ECAS). South Carolina Supplement. U.S. Army

DTIC Science & Technology

1994-04-01

Cyanamide. 156627 2.50 Captan 133062 25.00 Carbaryl 63252 25.00 Carbon Disulfide 75150 150.00 Carbon Tetrachloride 56235 150.00. Carbonyl Sulfide...1120714 + b-Propiolactone 57578 7.50 Propoxur 114261 2.50 Propylene Dichloride 78875 1750.00 1,2 Propylene Oxide 75569 250.00 Propylenimine (1,2

Nitroguanidine Wastewater Pollution Control Technology: Phase 2 Wastewater Characterization and Analytical Methods Development for Organics

DTIC Science & Technology

1984-03-01

a....... .6 Thin Layer Chromatographic (TLC) Analyses... o................. ......a... 7 RESULTS AND DISCUSSIONo.....................o...Beckman 5230 UV/visible spectrophotometer was used for colorimetric determinations of urea and cyanamide. Urea was hydrolyzed by urease and...correlation coefficients were 0.9999. THIN LAYER CHROMATOGRAPHIC (TLC) ANALYSES Cellulose plates were used and were developed in the following systems: 3N

Review of Laboratory Program on Degradation Mechanisms in Soil of Wastewater From Nitroguanidine Manufacture

DTIC Science & Technology

1987-03-01

in./hr) (3). Nutrients (organic nitrogen, ammonia-nitrogen, nitrate/I nitrite-nitrogen, potassium , and phosphorus) in SFAAP soils are generally...A mixture con- taining equal portions of these was diluted with 0.085 percent potassium chloride. The 30 percent solution was filtered and the...01 L (d) Cyanamide - Spectrophotometric determination after complexation with pentacyanoamine ferrate reagent. Detection limit was approximately 100

Pre Conference Hazardous Materials Workshop, West/East Coast Safety Conference, held 3-4 October/31 October - 1 November 1981,

DTIC Science & Technology

1981-01-01

itation and ulceration of skin Blacher,. picklers (nicals). refiners (metals). tinners. c,".:mical manufactur- ing Hydrofluoric X Severe burning of skin...strong solutions are used) DNc,.g, felt hat industry Nitric X Severe skin burns and ulcers Nitric acid worker%, electroplaters. met- al refincr, acid...Fertilije, makers, gr:cultural workers. Calcium cyanamide alkali salt makers Calcium oxide, carbon- X Dermatitis,. burns , or ulcers Lime %orkers

Preparation of nitrogen-doped carbon tubes

DOEpatents

Chung, Hoon Taek; Zelenay, Piotr

2015-12-22

A method for synthesizing nitrogen-doped carbon tubes involves preparing a solution of cyanamide and a suitable transition metal-containing salt in a solvent, evaporating the solvent to form a solid, and pyrolyzing the solid under an inert atmosphere under conditions suitable for the production of nitrogen-doped carbon tubes from the solid. Pyrolyzing for a shorter period of time followed by rapid cooling resulted in a tubes with a narrower average diameter.

Air Emissions Inventory Guidance Document for Mobile Sources at Air Force Installations

DTIC Science & Technology

2002-01-01

Compounds 156-62-7 Calcium cyanamide 133-06-2 Captan 63-25-2 Carbaryl 75-15-0 Carbon disulfide 56-23-5 Carbon tetrachloride 463-58-1 Carbonyl sulfide...1120-71-4 1,3-Propane sultone 57-57-8 beta-Propiolactone, 123-38-6 Propionaldehyde 114-26-1 Propoxur (Baygon) 78-87-5 Propylene dichloride, (1 ,2...Dichlorvos 62-75-9 N-Nitrosodimethylamine 63-25-2 Carbaryl 64-67-5 Diethyl sulfate 67-56-1 Methanol 67-66-3 Chloroform 67-72-1 Hexachloroethane 68-12-2

Non-enzymatic synthesis of the coenzymes, uridine diphosphate glucose and cytidine diphosphate choline, and other phosphorylated metabolic intermediates

NASA Technical Reports Server (NTRS)

Mar, A.; Dworkin, J.; Oro, J.

1987-01-01

Using urea and cyanamide, the two condensing agents considered to have been present on the primitive earth, uridine diphosphate glucose (UDPG), cytidine diphosphate choline (CDP-choline), glucose-1-phosphate (G1P), and glucose-6-phosphate (G6P) were synthesized under simulated prebiotic conditions. The reaction products were separated and identified using paper chromatography, thin layer chromatography, enzymatic analyses, and ion-pair reverse-phase high performance liquid chromatography. The possibility of nonenzymatic synthesis of metabolic intermediates on the primitive earth from simple precursors was thus demonstrated.

Flammability Characteristics of Fiber-Reinforced Composite Materials for the Composite Infantry Fighting Vehicle

DTIC Science & Technology

1990-09-01

Comments MTL-1 SZIPolyester 70/30 E-701 Baseline MTL-2 S2IPdyester’ 70130 Owens - Corning MTL-3 S2/Polyester* 70/30 American-Cyanamide MTL-5 S2IPhenolic...80120 Owens - Corning *Resin formulation is ro rietary t ~ e s i n is 50150 phenofc-FvB. ’ Organic polymers a re one of the major constituents of...SPECTROMETRY OF MTL-2, OWENS - CORNING ; 900°C IN HELIUM Peak No. Identification Carbon Monoxide and Carbon Dioxide Formaldehyde Propene 1.2-Propadiene 1

9-cis Retinoic Acid is the ALDH1A1 Product that Stimulates Melanogenesis

PubMed Central

Paterson, Elyse K.; Ho, Hsiang; Kapadia, Rubina; Ganesan, Anand K.

2013-01-01

Aldehyde dehydrogenase 1A1 (ALDH1A1), an enzyme that catalyzes the conversion of lipid aldehydes to lipid carboxylic acids, plays pleiotropic roles in UV-radiation resistance, melanogenesis, and stem cell maintenance. In this study, a combination of RNAi and pharmacologic approaches were used to determine which ALDH1A1 substrates and products regulate melanogenesis. Initial studies revealed that neither the UV-induced lipid aldehyde 4-hydroxy-2-nonenal nor the ALDH1A1 product all-trans retinoic acid appreciably induced melanogenesis. In contrast, both the ALDH1A1 substrate 9-cis retinal and its corresponding product 9-cis retinoic acid potently induced the accumulation of MITF mRNA, Tyrosinase mRNA, and melanin. ALDH1A1 depletion inhibited the ability of 9-cis retinal but not 9-cis retinoic acid to stimulate melanogenesis, indicating that ALDH1A1 regulates melanogenesis by catalyzing the conversion of 9-cis retinal to 9-cis retinoic acid. The addition of potent ALDH1A inhibitors (cyanamide or Angeli’s salt) suppressed Tyrosinase and MITF mRNA accumulation in vitro and also melanin accumulation in skin equivalents, suggesting that 9-cis retinoids regulate melanogenesis in the intact epidermis. Taken together, these studies not only identify cyanamide as a potential novel treatment for hyperpigmentary disorders, but also identify 9-cis retinoic acid as a pigment stimulatory agent that may have clinical utility in the treatment of hypopigmentary disorders, such as vitiligo. PMID:23489423

Allelopathy in the natural and agricultural ecosystems and isolation of potent allelochemicals from Velvet bean (Mucuna pruriens) and Hairy vetch (Vicia villosa).

PubMed

Fujii, Yoshiharu

2003-06-01

We have studied on allelopathy of plants and developed methods to identify the effective substances in root exudates, leaf leacheate, and volatile chemicals emitted from plants. We found traditional cover plants that show allelopathic activity are useful for weed control. It could eliminate the use of synthetic chemicals for this purpose. Allelopathy is a natural power of plants to protect themselves by producing natural organic chemicals. Some endemic plants in Asia, already known by farmers in the region, as either cover crops used in intercropping, hedgerow, or agroforestry, were found to possess strong allelopathic abilities. Our group identified several allelochemicals from these plants. These allelopathic cover crops, mostly leguminous plants, provide protein rich food, and grow easily without artificial fertilizers, herbicides, insecticides and fungicides. In this regards, these allelopathic cover crops could save food shortage in rural area, and are useful for environmental conservation. Screenings of allelopathic plants by specific bioassays and field tests have been conducted. Hairy vetch (Vicia villosa) and Velvet bean (Mucuna pruriens) are two promising species for the practical application of allelopathy. An amino acid, L-DOPA, unusual in plants, plays an important role as allelochemical in Velvet bean (Mucuna pruriens). Hairy vetch is the most promising cover plant for the weed control in orchard, vegetable and rice production and even for landscape amendment in abandoned field in Japan. We have isolated "cyanamide", a well known nitrogen fertilizer, from Hairy vetch. This is the first finding of naturally produced cyanamide in the world.

Synthesis of δ- and α-Carbolines via Nickel-Catalyzed [2 + 2 + 2] Cycloaddition of Functionalized Alkyne-Nitriles with Alkynes.

PubMed

Wang, Gaonan; You, Xu; Gan, Yi; Liu, Yuanhong

2017-01-06

A new method for the synthesis of δ- and α-carbolines through Ni-catalyzed [2 + 2 + 2] cycloaddition of ynamide-nitriles or alkyne-cyanamides with alkynes has been developed. The catalytic system of NiCl 2 (DME)/dppp/Zn with a low-cost Ni(II)-precursor was first utilized in Ni-catalyzed [2 + 2 + 2] cycloaddition reactions, and the in situ generated Lewis acid may play an important role for the successful transformation. Not only internal alkynes but also terminal alkynes undergo the desired cycloaddition reactions efficiently to furnish the carboline derivatives with wide diversity and functional group tolerance.

The Capital Budgeting Policies of the U. S. Shipbuilding Industry: An Analysis of Defense Industry Behavior

DTIC Science & Technology

1979-10-01

Johns - Manville ) and one whose net worth was comparable in 1976 (Cluett Peabody). • One company whose asset base was comparable to Lockheed’s in 1967...AVERAGE2 30.2 ’ KODAK ARMCO SFERRY RAND JOHNS - MANVILLE CLCETt PEABODY AMER.CYANAMID SINGER-1’ N.A. N.A. N.A. N.A. N.A. M.A. N.A. 9 11 10 22 4 13 N.A. 10...JIM WALTER 8 23 CUMMINS 58 8 MARTIN MARIETTA 9 90 SQUIBB 851 KOPPERS 708 UNION CAMP 624 INT’L MINING 68 2 JOHNS MANVILLE 814 EMERSON ELEC

Intrahippocampal injection of Cortistatin-14 impairs recognition memory consolidation in mice through activation of sst2, ghrelin and GABAA/B receptors.

PubMed

Jiang, Jinhong; Peng, Yali; He, Zhen; Wei, Lijuan; Jin, Weidong; Wang, Xiaoli; Chang, Min

2017-07-01

Cortistatin-14 (CST-14), a neuropeptide related to somatostatin, is primarily localized within the cortex and hippocampus. In the hippocampus, CST-14 inhibits CA1 neuronal pyramidal cell firing and co-exists with GABA. However, its role in cognitive is still not clarified. The first aim of our study was to elucidate the role of CST-14 signaling in consolidation and reconsolidation of recognition memory in mice, using novel object recognition task. The results showed that central CST-14 induced in impairment of long-term and short-term recognition memory, indicating memory consolidation impairment effect. Similarly, we found that CST-14 did not impaired long-term and short-term reconsolidation recognition memory. To further investigate the underlying mechanisms of CST-14 in memory process, we used cyclosomatostatin (c-SOM, a selective sst 1-5 receptor antagonist), cyanamid154806 (a selective sst 2 receptor antagonist), ODN-8 (a high affinity and selectivity compound for sst 3 receptor), [d-Lys 3 ]GHRP-6 (a selective ghrelin receptor antagonist), picrotoxin (PTX, a GABA A receptor antagonist), and sacolfen (a GABA B receptor antagonist) to research its effects in recognition. Our results firstly indicated that the memory-impairing effects of CST-14 were significantly reversed by c-SOM, cyanamid154806, [d-Lys 3 ]GHRP-6, PTX and sacolfen, but not ODN-8, suggesting that the blockage of recognition memory consolidation induced by CST-14 involves sst 2 , ghrelin and GABA system. The present study provides a potential strategy to regulate memory processes, providing new evidence that reconsolidation is not a simple reiteration of consolidation. Copyright © 2017 Elsevier B.V. All rights reserved.

The metabolism of ethanol-derived acetaldehyde by alcohol dehydrogenase (EC 1.1.1.1) and aldehyde dehydrogenase (EC 1.2.1.3) in Drosophila melanogaster larvae.

PubMed Central

Heinstra, P W; Geer, B W; Seykens, D; Langevin, M

1989-01-01

Both aldehyde dehydrogenase (ALDH, EC 1.2.1.3) and the aldehyde dehydrogenase activity of alcohol dehydrogenase (ADH, EC 1.1.1.1) were found to coexist in Drosophila melanogaster larvae. The enzymes, however, showed different inhibition patterns with respect to pyrazole, cyanamide and disulphiram. ALDH-1 and ALDH-2 isoenzymes were detected in larvae by electrophoretic methods. Nonetheless, in tracer studies in vivo, more than 75% of the acetaldehyde converted to acetate by the ADH ethanol-degrading pathway appeared to be also catalysed by the ADH enzyme. The larval fat body probably was the major site of this pathway. Images Fig. 1. Fig. 2. PMID:2499314

Synthesis and photocatalytic properties of graphitic carbon nitride nanofibers using porous anodic alumina templates

NASA Astrophysics Data System (ADS)

Suchitra, S. M.; Udayashankar, N. K.

2017-12-01

In the present study, we describe an effective method for the synthesis of Graphitic carbon nitride (GCN) nanostructures using porous anodic alumina (AAO) membrane as template by simple thermal condensation of cyanamide. Synthesized nanostructure was fully analysed by various techniques to detect its crystalline nature, morphology, luminescent properties followed by the evaluation of its photocatalytic activity in the degradation of Methylene blue dye. Structural analysis of synthesized GCNNF was systematically carried out using x-ray powder diffraction (XRD) and scanning electron microscope (SEM), and. The results confirmed the growth of GCN inside the nanochannels of anodic alumina templates. Luminescent properties of GCNNF were studied using photoluminescence (PL) spectroscopy. PL analysis showed the presence of a strong emission peak in the wavelength range of 350-600 nm in blue region. GCNNF displays higher photocatalytic performance in the photodegradation of methylene blue compare to the bulk GCN. Highlights 1. In the present paper, we report the synthesis of graphitic carbon nitride nanofibers (GCNNF) using porous anodic aluminium oxide membranes as templates through thermal condensation of cyanamide at 500 °C. 2. The synthesis of Graphitic carbon nitride nanofibers using porous andic alumina template is the efficient approach for increasing crystallinity and surface area. 3. The high surface area of graphitic carbon nitride nanofibers has a good impact on novel optical and photocatalytic properties of the bulkGCN. 4. AAO templating of GCN is one of the versatile method to produce tailorable GCN nanostructures with higher surface area and less number of structural defects. 5. Towards photocatalytic degradation of dyes, the tuning of physical properties is very essential thing hence we are succeeded in achieving better catalytic performance of GCN nanostructures by making use of AAO templates.

Outward current produced by somatostatin (SRIF) in rat anterior cingulate pyramidal cells in vitro

PubMed Central

Hicks, G A; Feniuk, W; Humphrey, P P A

1998-01-01

A high density of receptors for somatostatin (SRIF) exists in the anterior cingulate cortex but their function is unknown. Whole-cell patch clamp recordings were made from visualized deep layer pyramidal cells of the rat anterior cingulate cortex contained in isolated brain slices to investigate the putative effects of SRIF and to identify the receptor subtype(s) involved.SRIF (1–1000 nM) produced a concentration-dependent outward current which was associated with an increased membrane conductance, was sensitive to Ba2+ (300 μM–1 mM), and was absent in the presence of a maximal concentration of the GABAB receptor agonist, baclofen (100 μM). These observations suggest the outward current was carried by K+ ions.SRIF analogues also elicited outward currents with a rank potency order of (EC50, nM): octreotide (1.8)>BIM-23027 (3.7)>SRIF (20)=L-362,855 (20). BIM-23056 was without agonist or antagonist activity. Responses to L-362,855 were unlike those to the other agonists since they were sustained for the duration of the application.The sst2 receptor antagonist, L-Tyr8Cyanamid 154806 (1 μM), had no effect alone but partially reversed responses to submaximal concentrations of SRIF (100 nM, 44±6% reversal) and L-362,855 (100 nM, 70±6% reversal) and fully reversed the response to BIM-23027 (10 nM). In contrast, L-Tyr8Cyanamid 154806 did not antagonize the response to baclofen (10 μM).We conclude that SRIF activates a K+ conductance in anterior cingulate pyramidal neurones via an action predominantly at sst2 receptors. PMID:9630367

Study and application of molluscicides in Japan*

PubMed Central

Komiya, Yoshitaka

1961-01-01

For several years after the First World War calcium oxide was the main compound used in the control of Oncomelania nosophora in Japan. This was generally replaced in 1944 by calcium cyanamide; since 1952 the prefectural authorities in areas of endemic bilharziasis have increasingly turned to the use of sodium pentachlorophenate as the molluscicide of choice. Applied at a rate of 5 g per m2, this compound has been found to kill 70%-80% of snails per application. Laboratory and field experiments with calcium-arsenic compounds have been conducted in Japan and have indicated that these products have a relatively high molluscicidal effect; they have, however, not been used on a wide scale for snail control. PMID:14458130

Photodegradation of methyl red under visible light by mesoporous carbon nitride

NASA Astrophysics Data System (ADS)

Hu, Yueyue; Zhang, Min; Xiao, Zaozao; Jiang, Tao; Yan, Bing; Li, Jian

2018-02-01

Mesoporous carbon nitride (mpg-C3N4) with tunable microstructure has been successfully prepared through a simple polymerization reaction of cyanamide by a nano hard-templating approach. The obtained materials have been characterized using X-ray diffraction (XRD), N2 adsorption, and Fourier transform infrared (FT-IR) spectroscopy. The results show that the pore diameter of the mpg-C3N4 materials can be easily tuned from 3.8 to 10.5 nm. The mpg-C3N4 materials are demonstrated to exhibit much higher visible light photocatalytic activity than that of g-C3N4 for the degradation of aqueous methyl red (MR). The high surface areas and large pore volume contributed to the efficient visible light photocatalytic activity.

Synthesis of cytidine ribonucleotides by stepwise assembly of the heterocycle on a sugar phosphate.

PubMed

Ingar, Abdul-Aziz; Luke, Richard W A; Hayter, Barry R; Sutherland, John D

2003-06-06

Although various syntheses of the nucleic acid bases exist and ribose is a product of the formose reaction, no prebiotically plausible methods for attaching pyrimidine bases to ribose to give nucleosides have been described. Kinetic and thermodynamic factors are thought to mitigate against such condensation reactions in aqueous solution. This inability to produce pyrimidine nucleosides and hence nucleotides is a major stumbling block of the "RNA World" hypothesis and has led to suggestions of alternative nucleic acids as evolutionary precursors to RNA. Here, we show that a process in which the base is assembled in stages on a sugar phosphate can produce cytidine nucleotides. The sequential action of cyanamide and cyanoacetylene on arabinose-3-phosphate produces cytidine-2',3'-cyclophosphate and arabinocytidine-3'-phosphate.

Historical trends in chill hour accumulation and peach bud response to hydrogen cyanamide

USDA-ARS?s Scientific Manuscript database

Long held records for (low) chill hour accumulation have recently been broken several times in the southeastern US peach (Prunus persica) production areas. Long term historical average chill hour accumulation through February 15th in middle Georgia has dropped significantly over the last 15 years. T...

Aldehyde dehydrogenase-2 inhibition blocks remote preconditioning in experimental and human models.

PubMed

Contractor, Hussain; Støttrup, Nicolaj B; Cunnington, Colin; Manlhiot, Cedric; Diesch, Jonathan; Ormerod, Julian O M; Jensen, Rebekka; Bøtker, Hans Erik; Redington, Andrew; Schmidt, Michael R; Ashrafian, Houman; Kharbanda, Rajesh K

2013-05-01

Mitochondrial aldehyde dehydrogenase-2 (ALDH-2) is involved in preconditioning pathways, but its role in remote ischaemic preconditioning (rIPC) is unknown. We investigated its role in animal and human models of rIPC. (i) In a rabbit model of myocardial infarction, rIPC alone reduced infarct size [69 ± 5.8 % (n = 11) to 40 ± 6.5 % (n = 12), P = 0.019]. However, rIPC protection was lost after pre-treatment with the ALDH-2 inhibitor cyanamide (62 ± 7.6 % controls, n = 10, versus 61 ± 6.9 % rIPC after cyanamide, n = 10, P > 0.05). (ii) In a forearm plethysmography model of endothelial ischaemia-reperfusion injury, 24 individuals of Asian ethnic origin underwent combined rIPC and ischaemia-reperfusion (IR). 11 had wild-type (WT) enzyme and 13 carried the Glu504Lys (ALDH2*2) polymorphism (rendering ALDH-2 functionally inactive). In WT individuals, rIPC protected against impairment of response to acetylcholine (P = 0.9), but rIPC failed to protect carriers of Glu504Lys polymorphism (P = 0.004). (iii) In a second model of endothelial IR injury, 12 individuals participated in a double-blind placebo-controlled crossover study, receiving the ALDH-2 inhibitor disulfiram 600 mg od or placebo for 48 h prior to assessment of flow-mediated dilation (FMD) before and after combined rIPC and IR. With placebo, rIPC was effective with no difference in FMD before and after IR (6.18 ± 1.03 % and 4.76 ± 0.93 % P = 0.1), but disulfiram inhibited rIPC with a reduction in FMD after IR (7.87 ± 1.27 % and 3.05 ± 0.53 %, P = 0.001). This study demonstrates that ALDH-2 is involved in the rIPC pathway in three distinct rabbit and human models. This has potential implications for future clinical studies of remote conditioning.

Metabolic engineering of microbial competitive advantage for industrial fermentation processes.

PubMed

Shaw, A Joe; Lam, Felix H; Hamilton, Maureen; Consiglio, Andrew; MacEwen, Kyle; Brevnova, Elena E; Greenhagen, Emily; LaTouf, W Greg; South, Colin R; van Dijken, Hans; Stephanopoulos, Gregory

2016-08-05

Microbial contamination is an obstacle to widespread production of advanced biofuels and chemicals. Current practices such as process sterilization or antibiotic dosage carry excess costs or encourage the development of antibiotic resistance. We engineered Escherichia coli to assimilate melamine, a xenobiotic compound containing nitrogen. After adaptive laboratory evolution to improve pathway efficiency, the engineered strain rapidly outcompeted a control strain when melamine was supplied as the nitrogen source. We additionally engineered the yeasts Saccharomyces cerevisiae and Yarrowia lipolytica to assimilate nitrogen from cyanamide and phosphorus from potassium phosphite, and they outcompeted contaminating strains in several low-cost feedstocks. Supplying essential growth nutrients through xenobiotic or ecologically rare chemicals provides microbial competitive advantage with minimal external risks, given that engineered biocatalysts only have improved fitness within the customized fermentation environment. Copyright © 2016, American Association for the Advancement of Science.

Combination of carbon nitride and carbon nanotubes: synergistic catalysts for energy conversion.

PubMed

Gong, Yutong; Wang, Jing; Wei, Zhongzhe; Zhang, Pengfei; Li, Haoran; Wang, Yong

2014-08-01

Due to their versatile features and environmental friendliness, functionalized carbon materials show great potential in practical applications, especially in energy conversion. Developing carbon composites with properties that can be modulated by simply changing the ratio of the original materials is an intriguing synthetic strategy. Here, we took cyanamide and multiwalled carbon nanotubes as precursors and introduced a facile method to fabricate a series of graphitic carbon nitride/carbon nanotubes (g-C3 N4 /CNTs) composites. These composites demonstrated different practical applications with different weight ratios of the components, that is, they showed synergistic effects in optoelectronic conversion when g-C3 N4 was the main ingredient and in oxygen reduction reaction (ORR) when CNTs dominated the composites. Our experiments indicated that the high electrical conductivity of carbon nanotubes promoted the transmission of the charges in both cases. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Mechanical properties of neat polymer matrix materials and their unidirectional carbon fiber-reinforced composites

NASA Technical Reports Server (NTRS)

Zimmerman, Richard S.; Adams, Donald F.

1988-01-01

The mechanical properties of two neat resin systems for use in carbon fiber epoxy composites were characterized. This included tensile and shear stiffness and strengths, coefficients of thermal and moisture expansion, and fracture toughness. Tests were conducted on specimens in the dry and moisture-saturated states, at temperatures of 23, 82 and 121 C. The neat resins tested were American Cyanamid 1806 and Union Carbide ERX-4901B(MPDA). Results were compared to previously tested neat resins. Four unidirectional carbon fiber reinforced composites were mechanically characterized. Axial and transverse tension and in-plane shear strengths and stiffness were measured, as well as transverse coefficients of thermal and moisture expansion. Tests were conducted on dry specimens only at 23 and 100 C. The materials tested were AS4/3502, AS6/5245-C, T300/BP907, and C6000/1806 unidirectional composites. Scanning electron microscopic examination of fracture surfaces was performed to permit the correlation of observed failure modes with the environmental test conditions.

Mechanical properties testing of candidate polymer matrix materials for use in high performance composites

NASA Technical Reports Server (NTRS)

Zimmerman, R. S.; Adams, D. F.

1985-01-01

The mechanical properties of four candidate neat resin systems for use in graphite/epoxy composites are characterized. This includes tensile and shear stiffnesses and strengths, coefficients of thermal and moisture expansion, and fracture toughness. Tests are conducted on specimens in the dry state and moisture-saturated, at temperatures of 23C, 82C and 121C. The neat resins tested are Hexcel HX-1504, Narmco 5245-C, American Cyanamid CYCOM 907, and Union Carbide ERX-4901A (MDA). Results are compared with those obtained for four other epoxy resins tested in a prior program, i.e., Hercules 3502, 2220-1, and 2220-3, and Ciba-Geigy Fibredux 914, as well as with available Hercules 3501-6 data. Scanning electron microscopic examination of fracture surfaces is performed to permit the correlation of observed failure modes with the environmental test conditions. A finite element micromechanics analysis is used to predict unidirectional composite response under various test conditions, using the measured neat resin properties as input data.

Dark Photocatalysis: Storage of Solar Energy in Carbon Nitride for Time-Delayed Hydrogen Generation.

PubMed

Lau, Vincent Wing-Hei; Klose, Daniel; Kasap, Hatice; Podjaski, Filip; Pignié, Marie-Claire; Reisner, Erwin; Jeschke, Gunnar; Lotsch, Bettina V

2017-01-09

While natural photosynthesis serves as the model system for efficient charge separation and decoupling of redox reactions, bio-inspired artificial systems typically lack applicability owing to synthetic challenges and structural complexity. We present herein a simple and inexpensive system that, under solar irradiation, forms highly reductive radicals in the presence of an electron donor, with lifetimes exceeding the diurnal cycle. This radical species is formed within a cyanamide-functionalized polymeric network of heptazine units and can give off its trapped electrons in the dark to yield H 2 , triggered by a co-catalyst, thus enabling the temporal decoupling of the light and dark reactions of photocatalytic hydrogen production through the radical's longevity. The system introduced here thus demonstrates a new approach for storing sunlight as long-lived radicals, and provides the structural basis for designing photocatalysts with long-lived photo-induced states. © 2016 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.

Hydrogen cyanamide on citrus: preliminary data on phytotoxicity and influence on flush in potted and field trees

USDA-ARS?s Scientific Manuscript database

Bloom in individual citrus trees typically continues for more than a month in south Florida, with even greater bloom duration within most orchard blocks because of variation in bloom timing between trees. Prolonged bloom contributes to variable fruit maturity as harvest approaches and increases seve...

Potent Inhibitors of Plasmodial Serine Hydroxymethyltransferase (SHMT) Featuring a Spirocyclic Scaffold.

PubMed

Schwertz, Geoffrey; Witschel, Matthias C; Rottmann, Matthias; Leartsakulpanich, Ubolsree; Chitnumsub, Penchit; Jaruwat, Aritsara; Amornwatcharapong, Watcharee; Ittarat, Wanwipa; Schäfer, Anja; Aponte, Raphael A; Trapp, Nils; Chaiyen, Pimchai; Diederich, François

2018-05-08

With the discovery that serine hydroxymethyltransferase (SHMT) is a druggable target for antimalarials, the aim of this study was to design novel inhibitors of this key enzyme in the folate biosynthesis cycle. Herein, 19 novel spirocyclic ligands based on either 2-indolinone or dihydroindene scaffolds and featuring a pyrazolopyran core are reported. Strong target affinities for Plasmodium falciparum (Pf) SHMT (14-76 nm) and cellular potencies in the low nanomolar range (165-334 nm) were measured together with interesting selectivity against human cytosolic SHMT1 (hSHMT1). Four co-crystal structures with Plasmodium vivax (Pv) SHMT solved at 2.2-2.4 Å resolution revealed the key role of the vinylogous cyanamide for anchoring ligands within the active site. The spirocyclic motif in the molecules enforces the pyrazolopyran core to adopt a substantially more curved conformation than that of previous non-spirocyclic analogues. Finally, solvation of the spirocyclic lactam ring of the receptor-bound ligands is discussed. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Exploration and pharmacokinetic profiling of phenylalanine based carbamates as novel substance p 1-7 analogues.

PubMed

Fransson, Rebecca; Nordvall, Gunnar; Bylund, Johan; Carlsson-Jonsson, Anna; Kratz, Jadel M; Svensson, Richard; Artursson, Per; Hallberg, Mathias; Sandström, Anja

2014-12-11

The bioactive metabolite of Substance P, the heptapeptide SP1-7 (H-Arg-Pro-Lys-Pro-Gln-Gln-Phe-OH), has been shown to attenuate signs of hyperalgesia in diabetic mice, which indicate a possible use of compounds targeting the SP1-7 binding site as analgesics for neuropathic pain. Aiming at the development of drug-like SP1-7 peptidomimetics we have previously reported on the discovery of H-Phe-Phe-NH2 as a high affinity lead compound. Unfortunately, the pharmacophore of this compound was accompanied by a poor pharmacokinetic (PK) profile. Herein, further lead optimization of H-Phe-Phe-NH2 by substituting the N-terminal phenylalanine for a benzylcarbamate group giving a new type of SP1-7 analogues with good binding affinities is reported. Extensive in vitro as well as in vivo PK characterization is presented for this compound. Evaluation of different C-terminal functional groups, i.e., hydroxamic acid, acyl sulfonamide, acyl cyanamide, acyl hydrazine, and oxadiazole, suggested hydroxamic acid as a bioisosteric replacement for the original primary amide.

Exploration and Pharmacokinetic Profiling of Phenylalanine Based Carbamates as Novel Substance P 1–7 Analogues

PubMed Central

2014-01-01

The bioactive metabolite of Substance P, the heptapeptide SP1–7 (H-Arg-Pro-Lys-Pro-Gln-Gln-Phe-OH), has been shown to attenuate signs of hyperalgesia in diabetic mice, which indicate a possible use of compounds targeting the SP1–7 binding site as analgesics for neuropathic pain. Aiming at the development of drug-like SP1–7 peptidomimetics we have previously reported on the discovery of H-Phe-Phe-NH2 as a high affinity lead compound. Unfortunately, the pharmacophore of this compound was accompanied by a poor pharmacokinetic (PK) profile. Herein, further lead optimization of H-Phe-Phe-NH2 by substituting the N-terminal phenylalanine for a benzylcarbamate group giving a new type of SP1–7 analogues with good binding affinities is reported. Extensive in vitro as well as in vivo PK characterization is presented for this compound. Evaluation of different C-terminal functional groups, i.e., hydroxamic acid, acyl sulfonamide, acyl cyanamide, acyl hydrazine, and oxadiazole, suggested hydroxamic acid as a bioisosteric replacement for the original primary amide. PMID:25516784

DOE Office of Scientific and Technical Information (OSTI.GOV)

Morris, G.D.L.

One of the many joint venture alliances recently announced in the petrochemical sector is ending in divorce. Hoechst Celanese Chemical (Dallas) and Methanex Corp. (Vancouver) are in the process of dissolving the partnership they had formed to restart Hoechst Celanese's methanol plant at Clear Lake, TX. Hoechst Celanese says it is actively seeking replacement partners and has several likely prospects, while Methanex is concentrating on its other ventures. Those include its just-completed acquisition of Fletcher Challenge's (Auckland, NZ) methanol business and a joint venture with American Cyanamid to convert an ammonia plant at Fortier, LA to methanol. Methanex will stillmore » be the world's largest producer of methanol. Officially, the negotiations between Methanex and Hoechst Celanese just broke down over the last month or so,' says Steve Yurich, operations manager for the Clear Lake plant. Market sources, however, say that Methanex found itself with too many irons in the fire' and pulled out before it ran into financial or perhaps even antitrust difficulties.« less

Mechanism of the sulfurisation of phosphines and phosphites using 3-amino-1,2,4-dithiazole-5-thione (xanthane hydride).

PubMed

Hanusek, Jirí; Russell, Mark A; Laws, Andrew P; Jansa, Petr; Atherton, John H; Fettes, Kevin; Page, Michael I

2007-02-07

Contrary to a previous report, the sulfurisation of phosphorus(III) derivatives by 3-amino-1,2,4-dithiazole-5-thione (xanthane hydride) does not yield carbon disulfide and cyanamide as the additional reaction products. The reaction of xanthane hydride with triphenyl phosphine or trimethyl phosphite yields triphenyl phosphine sulfide or trimethyl thiophosphate, respectively, and thiocarbamoyl isothiocyanate which has been trapped with nucleophiles. The reaction pathway involves initial nucleophilic attack of the phosphorus at sulfur next to the thiocarbonyl group of xanthane hydride followed by decomposition of the phosphonium intermediate formed to products. The Hammett rho-values for the sulfurisation of substituted triphenyl phosphines and triphenyl phosphites in acetonitrile are approximately -1.0. The entropies of activation are very negative (-114+/-15 J mol-1 K-1) with little dependence on solvent which is consistent with a bimolecular association step leading to the transition state. The negative values of DeltaS(not equal) and rho values indicate that the rate limiting step of the sulfurisation reaction is formation of the phosphonium ion intermediate which has an early transition state with little covalent bond formation. The site of nucleophilic attack has been also confirmed using computational calculations.

Crab shell chitin whiskers reinforced natural rubber nanocomposites. 3. Effect of chemical modification of chitin whiskers.

PubMed

Gopalan Nair, Kalaprasad; Dufresne, Alain; Gandini, Alessandro; Belgacem, Mohamed Naceur

2003-01-01

The purpose of this study was to chemically modify the surface of chitin whiskers and to investigate the effect of the incorporation of these modified whiskers into a natural rubber (NR) matrix on the properties of the ensuing nanocomposite. Different chemical coupling agents were tested, namely, phenyl isocyanate (PI), alkenyl succinic anhydride (ASA) (Accosize 18 from American Cyanamid), and 3-isopropenyl-alpha,alpha'-dimethylbenzyl isocyanate (TMI). The extent of chemical modification was evaluated by Fourier transform infrared (FTIR) spectroscopy, transmission electron microscopy (TEM), and surface energy analysis. After chemical modification, nanocomposite films were obtained using a toluene natural rubber solution in which the whiskers were dispersed. Their mechanical properties were found to be inferior to those of unmodified chitin/NR composites presented in our previous study. In fact, even though there is an increase in filler-matrix interaction as a result of chemical modification of the chitin whiskers, this does not contribute to the improvement in the mechanical properties of the resulting nanocomposite. It is concluded that this loss of performance is due to the partial destruction of the three-dimensional network of chitin whiskers assumed to be present in the unmodified composites.

The Chemistry of Nitroxyl-Releasing Compounds

PubMed Central

DuMond, Jenna F.

2011-01-01

Abstract Nitroxyl (HNO) demonstrates a diverse and unique biological profile compared to nitric oxide, a redox-related compound. Although numerous studies support the use of HNO as a therapeutic agent, the inherent chemical reactivity of HNO requires the use of donor molecules. Two general chemical strategies currently exist for HNO generation from nitrogen-containing molecules: (i) the disproportionation of hydroxylamine derivatives containing good leaving groups attached to the nitrogen atom and (ii) the decomposition of nitroso compounds (X-N=O, where X represents a good leaving group). This review summarizes the synthesis and structure, the HNO-releasing mechanisms, kinetics and by-product formation, and alternative reactions of six major groups of HNO donors: Angeli's salt, Piloty's acid and its derivatives, cyanamide, diazenium diolate-derived compounds, acyl nitroso compounds, and acyloxy nitroso compounds. A large body of work exists defining these six groups of HNO donors and the overall chemistry of each donor requires consideration in light of its ability to produce HNO. The increasing interest in HNO biology and the potential of HNO-based therapeutics presents exciting opportunities to further develop HNO donors as both research tools and potential treatments. Antioxid. Redox Signal. 14, 1637–1648. PMID:21235345

[Effects of different application rates of calcium cyanamide on soil microbial biomass and enzyme activity in cucumber continuous cropping].

PubMed

Zhang, Xue-peng; Ning, Tang-yuan; Yang, Yan; Sun, Tao; Zhang, Shu-min; Wang, Bin

2015-10-01

A 2-year field experiment was conducted to study the effects of CaCN2 combined with cucumber straw retention on soil microbial biomass carbon (SMBC) , soil microbial biomass nitrogen (SMBN) and soil enzyme activities under cucumber continuous cropping system. Four treatments were used in this study as follows: CK (null CaCN2), CaCN2-90 (1350 kg CaCN2 . hm-2) CaCN2-60 (900 kg CaCN2 . hm-2), CaCN2-30 (450 kg CaCN2 . hm-2). The results indicated that, compared with the other treatments, CaCN2-90 treatment significantly decreased SMBC in 0-10 cm soil layer at seedling stage, but increased SMBC in 0-20 cm soil layer after early-fruit stage. Compared with CK, CaCN2 increased SMBC in 0-20 cm soil layer at late-fruit stage, and increased SMBN in 0-10 cm soil layer at mid- and late-fruit stages, however there was no significant trend among CaCN2 treatments in the first year (2012), while in the second year (2013) SMBN increased with the increasing CaCN2 amount after mid-fruit stage. CaCN2 increased straw decaying and nutrients releasing, and also increased soil organic matter. Furthermore, the CaCN2-90 could accelerate straw decomposition. Compared with CK, CaCN2 effectively increased soil urease, catalase and polyphenol oxidase activity. The soil urease activity increased while the polyphenol oxidase activity decreased with the increase of CaCN2, and CaCN2-60 could significantly improve catalase activity. Soil organic matter, urease activity and catalase activity had significant positive correlations with SMBC and SMBN. However, polyphenol oxidase activity was negatively correlated to SMBC and SMBN. Our findings indicated that CaCN2 application at 900 kg . hm-2 combined with cucumber straw retention could effectively improve soil environment, alleviating the soil obstacles under the cucumber continuous cropping system.

Are Polyphosphates or Phosphate Esters Prebiotic Reagents?

NASA Technical Reports Server (NTRS)

Keefe, Anthony D.; Miller, Stanley L.

1995-01-01

It is widely held that there was a phosphate compound in prebiotic chemistry that played the role of adenosine triphosphate and that the first living organisms had ribose-phosphate in the backbone of their genetic material. However, there are no known efficient prebiotic synthesis of high-energy phosphates or phosphate esters. We review the occurrence of phosphates in nature, the efficiency of the volcanic synthesis of P4O10, the efficiency of polyphosphate synthesis by heating phosphate minerals under geological conditions, and the use of high-energy organic compounds such as cyanamide or hydrogen cyanide. These are shown to be inefficient processes especially when the hydrolysis of the polyphosphates is taken into account. For example, if a whole atmosphere of methane or carbon monoxide were converted to cyanide which somehow synthesized polyphosphates quantitatively, the polyphosphate concentration in the ocean would still have been insignificant. We also attempted to find more efficient high-energy polymerizing agents by spark discharge syntheses, but without success. There may still be undiscovered robust prebiotic syntheses of polyphosphates, or mechanisms for concentrating them, but we conclude that phosphate esters may not have been constituents of the first genetic material. Phosphoanhydrides are also unlikely as prebiotic energy sources.

Selective derivatization and sequestration of ribose from a prebiotic mix.

PubMed

Springsteen, Greg; Joyce, Gerald F

2004-08-11

Observations regarding the catalytic potential of RNA and the role of RNA in biology have formed the basis for the "RNA world" hypothesis, which suggests that a genetic system based on self-replicating polyribonucleotides preceded modern biology. However, attempts to devise a realistic prebiotic synthesis of nucleic acids from simple starting materials have been plagued by problems of poor chemical selectivity, lack of stereo- and regiospecificity, and similar rates of formation and degradation of some of the key intermediates. For example, ribose would have been only a small component of a highly complex mix of sugars resulting from the condensation of formaldehyde in a prebiotic world. In addition, ribose is more reactive and degrades more rapidly compared with most other monosaccharides. This study demonstrates an approach for the preferential sequestration of ribose relative to other sugars that takes advantage of its greater reactivity. Cyanamide reacts especially rapidly with ribose to form a stable bicyclic adduct. This product crystallizes spontaneously in aqueous solution, whereas the corresponding products derived from threose, galactose, glucose, mannose, and each of the other pentoses do not. Furthermore, when employing a racemic mixture of d- and l-ribose, enantiomerically twinned crystals are formed that contain discrete homochiral domains.

Toward an Aqueous Solar Battery: Direct Electrochemical Storage of Solar Energy in Carbon Nitrides.

PubMed

Podjaski, Filip; Kröger, Julia; Lotsch, Bettina V

2018-03-01

Graphitic carbon nitrides have emerged as an earth-abundant family of polymeric materials for solar energy conversion. Herein, a 2D cyanamide-functionalized polyheptazine imide (NCN-PHI) is reported, which for the first time enables the synergistic coupling of two key functions of energy conversion within one single material: light harvesting and electrical energy storage. Photo-electrochemical measurements in aqueous electrolytes reveal the underlying mechanism of this "solar battery" material: the charge storage in NCN-PHI is based on the photoreduction of the carbon nitride backbone and charge compensation is realized by adsorption of alkali metal ions within the NCN-PHI layers and at the solution interface. The photoreduced carbon nitride can thus be described as a battery anode operating as a pseudocapacitor, which can store light-induced charge in the form of long-lived, "trapped" electrons for hours. Importantly, the potential window of this process is not limited by the water reduction reaction due to the high intrinsic overpotential of carbon nitrides for hydrogen evolution, potentially enabling new applications for aqueous batteries. Thus, the feasibility of light-induced electrical energy storage and release on demand by a one-component light-charged battery anode is demonstrated, which provides a sustainable solution to overcome the intermittency of solar radiation. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Suppression on plant-parasitic nematodes using a soil fumigation strategy based on ammonium bicarbonate and its effects on the nematode community

PubMed Central

Su, Lanxi; Ruan, Yunze; Yang, Xiujuan; Wang, Kang; Li, Rong; Shen, Qirong

2015-01-01

Banana production is severely hindered by plant-parasitic nematodes in acidic, sandy soil. This study investigated the possibility of applying a novel fumigation agent based on ammonium bicarbonate as a strategy for controlling plant-parasitic nematodes under sealed conditions. Moreover, its effects on the nematode community in pot and field experiments were also measured using morphology and feeding-habit based classification and the PCR-DGGE method. Results showed that a mixture (LAB) of lime (L) and ammonium bicarbonate (AB) in suitable additive amounts (0.857 g kg−1 of L and 0.428 g kg−1 of AB) showed stronger nematicidal ability than did the use of AB alone or the use of ammonium hydroxide (AH) and calcium cyanamide (CC) with an equal nitrogen amount. The nematode community was altered by the different fumigants, and LAB showed an excellent plant-parasitic nematicidal ability, especially for Meloidogyne and Rotylenchulus, as revealed by morphology and feeding-habit based classification, and for Meloidogyne, as revealed by the PCR-DGGE method. Fungivores and omnivore-predators were more sensitive to the direct effects of the chemicals than bacterivores. This study explored a novel fumigation agent for controlling plant-parasitic nematodes based on LAB and provides a potential strategy to ensure the worldwide development of the banana industry. PMID:26621630

Polymer-assisted iron oxide magnetic nanoparticle immobilized keratinase

NASA Astrophysics Data System (ADS)

Konwarh, Rocktotpal; Karak, Niranjan; Rai, Sudhir Kumar; Mukherjee, Ashis Kumar

2009-06-01

Nanotechnology holds the prospect for avant-garde changes to improve the performance of materials in various sectors. The domain of enzyme biotechnology is no exception. Immobilization of industrially important enzymes onto nanomaterials, with improved performance, would pave the way to myriad application-based commercialization. Keratinase produced by Bacillus subtilis was immobilized onto poly(ethylene glycol)-supported Fe3O4 superparamagnetic nanoparticles. The optimization process showed that the highest enzyme activity was noted when immobilized onto cyanamide-activated PEG-assisted MNP prepared under conditions of 25 °C and pH 7.2 of the reaction mixture before addition of H2O2 (3% w/w), 2% (w/v) PEG6000 and 0.062:1 molar ratio of PEG to FeCl2·4H2O. Further statistical optimization using response surface methodology yielded an R2 value that could explain more than 94% of the sample variations. Along with the magnetization studies, the immobilization of the enzyme onto the PEG-assisted MNP was characterized by UV, XRD, FTIR and TEM. The immobilization process had resulted in an almost fourfold increase in the enzyme activity over the free enzyme. Furthermore, the immobilized enzyme exhibited a significant thermostability, storage stability and recyclability. The leather-industry-oriented application of the immobilized enzyme was tested for the dehairing of goat-skin.

Effect of organic amendments on quality indexes in an italian agricultural soil

NASA Astrophysics Data System (ADS)

Scotti, R.; Rao, M. A.; D'Ascoli, R.; Scelza, R.; Marzaioli, R.; Rutigliano, F. A.; Gianfreda, L.

2009-04-01

Intensive agricultural practices can determine a decline in soil fertility which represents the main constraint to agricultural productivity. In particular, the progressive reduction in soil organic matter, without an adequate restoration, may threaten soil fertility and agriculture sustainability. Some soil management practices can improve soil quality by adding organic amendments as alternative to the sole use of mineral fertilizers for increasing plant quality and growth. A large number of soil properties can be used to define changes in soil quality. In particular, although more emphasis has been given in literature to physical and chemical properties, biological properties, strictly linked to soil fertility, can be valid even more sensitive indicators. Among these, soil enzyme activities and microbial biomass may provide an "early warning" of soil quality and health changes. The aim of this work was to study the effect of preventive sterilization treatment and organic fertilization on enzymatic activities (dehydrogenase, arylsulphatase, beta-glucosidase, phosphatase, urease) and microbial biomass C in an agricultural soil under crop rotation. The study was carried out on an agricultural soil sited in Campania region (South Italy). At the beginning of experiment sterilizing treatments to control soilborne pathogens and weeds were performed by solarization and calcium cyanamide addition to soil. Organic fertilization was carried out by adding compost from vegetable residues, ricin seed exhaust (Rigen) and straw, singly or in association. Three samplings were performed at three different stages of crop rotation: I) September 2005, immediately after the treatments; II) December 2005, after a lettuce cycle; III) January 2007, after peppers and lettuce cycles. The soil sampling followed a W scheme, with five sub-samples for each plot. Soils were sieved at 2 mm mesh and air dried to determine physical and chemical properties; in addition a suitable amount of soils

Use of collagen film as a dural substitute: preliminary animal studies.

PubMed

Collins, R L; Christiansen, D; Zazanis, G A; Silver, F H

1991-02-01

Cadaver grafts, laminated metallic materials, and synthetic fabrics have been evaluated as dural substitutes. Use of cadaver tissues is limited by fear of transmission of infectious disease while use of synthetic materials is associated with implant encapsulation and foreign body reactions. The purpose of this study is to evaluate the use of collagen film as a dural substitute. Collagen films prepared from bovine skin were used to replace the dura of rabbits and histological observations were made at 16, 28, 42, and 56 days postimplantation. Controls consisted of dura that was removed and then reattached. Control dura showed no signs of inflammation or adhesion to underlying tissue at 16 and 28 days postimplantation. By 56 days postimplantation, extensive connective tissue deposition was observed in close proximity to adjacent bone as well as pia arachnoid adhesions. Implanted collagen film behaved in a similar manner to control dura showing minimal inflammatory response at all time periods. At 56 days postimplantation collagen film appeared strongly infiltrated by connective tissue cells that deposited new collagen. The results of this study suggest that a reconstituted type I collagen film crosslinked with cyanamide acts as a temporary barrier preventing loss of fluid and adhesion formation. It is replaced after approximately 2 months with host collagen with limited inflammatory and fibrotic complications. Further studies are needed to completely characterize the new connective tissue formed as well as long-term biocompatibility and functioning of a reconstituted collagen dural substitute.

Detection of Potential TNA and RNA Nucleoside Precursors in a Prebiotic Mixture by Pure Shift Diffusion-Ordered NMR Spectroscopy

PubMed Central

Islam, Saidul; Aguilar, Juan A; Powner, Matthew W; Nilsson, Mathias; Morris, Gareth A; Sutherland, John D

2013-01-01

In the context of prebiotic chemistry, one of the characteristics of mixed nitrogenous-oxygenous chemistry is its propensity to give rise to highly complex reaction mixtures. There is therefore an urgent need to develop improved spectroscopic techniques if onerous chromatographic separations are to be avoided. One potential avenue is the combination of pure shift methodology, in which NMR spectra are measured with greatly improved resolution by suppressing multiplet structure, with diffusion-ordered spectroscopy, in which NMR signals from different species are distinguished through their different rates of diffusion. Such a combination has the added advantage of working with intact mixtures, allowing analyses to be carried out without perturbing mixtures in which chemical entities are part of a network of reactions in equilibrium. As part of a systems chemistry approach towards investigating the self-assembly of potentially prebiotic small molecules, we have analysed the complex mixture arising from mixing glycolaldehyde and cyanamide, in a first application of pure shift DOSY NMR to the characterisation of a partially unknown reaction composition. The work presented illustrates the potential of pure shift DOSY to be applied to chemistries that give rise to mixtures of compounds in which the NMR signal resolution is poor. The direct formation of potential RNA and TNA nucleoside precursors, amongst other adducts, was observed. These preliminary observations may have implications for the potentially prebiotic assembly chemistry of pyrimidine threonucleotides, and therefore of TNA, by using recently reported chemistries that yield the activated pyridimidine ribonucleotides. PMID:23371787

Synthesis of guanosine and its derivatives from 5-amino-1-beta-D-ribofuranosyl-e-imidazolecarboxamide. IV. A new route to guanosine via cyanamide derivative.

PubMed Central

Yamazaki, A; Okutsu, M; Yamada, Y

1976-01-01

4-Cyanamido-5-imidazolecarboxamide (IV) was prepared by brief treatment of 5-(S-methylisothiocarbamoyl) amino-4-imidazolecarboxamide (V) with alkali. Compound VI was converted in an alkaline solution to either guanine (VII) or isoguanine (VIII), depending on the concentration of alkali. This procedure was applied to the synthesis of 2',3'-0-isopropylideneguanosine (XVI) from the riboside of 5-(N'-benzoyl-S-methylthiocarbamoyl) amino-4-imidazolecarboxamide (IX), PROviding a new route to XVI. PMID:1250702

Gravimetric measurements of materials outgassing applied to graphite-epoxy laminates

NASA Technical Reports Server (NTRS)

Scialdone, John J.

1990-01-01

The outgassing rates of two graphite-epoxy laminates, American Cyanamide 985B-626 and HST-7B-112, were obtained using a gravimetric method. The rates as a function of time and temperature were derived from the measurements of their mass losses at temperatures varying from 25 to 150 C and for a time span of up to 400 hours in a vacuum. The data from those measurements were reduced to obtain the outgassing activation energies, the mass losses per unit mass or area, and the corresponding outgassing rates. The rates are expressed in closed-form equations and are directly usable for modeling computations. The procedures to obtain these parameters are shown and may be used for the evaluation of other materials. The results of the tests show that the activation energies of the two materials are: 4630 cal/mole for the 985B-626 materials and 4791 cal/mole for the HST-7B-112 sample no. 10 Graphite Epoxy. The outgassing rates of these materials are in the 1OE-5 g sq cm/hr range and they decay according to a power of time of 0.60 at 25 C, indicating that the outgassing process is mainly a diffusion at that temperature. The normalized mass losses versus time obtained from these tests were compared to the discrete results obtained from the ASTM-E595 tests. The comparison provides general indications on the effects of temperature and time in relation to the ASTM test values obtained at 125 C for a 24-hour test duration.

Gravimetric measurements of materials outgassing applied to graphite-epoxy laminates

NASA Technical Reports Server (NTRS)

Scialdone, John J.

1989-01-01

The outgassing rates of two graphite-epoxy laminates, American Cyanamide 985B-626 and HST-7B-112, were obtained using a gravimetric method. The rates as a function of time and temperature were derived from the measurements of their mass losses at temperatures varying from 25 to 150 C and for a time span of up to 400 hours in a vacuum. The data from those measurements were reduced to obtain the outgassing activation energies, the mass losses per unit mass or area, and the corresponding outgassing rates. The rates are expressed in closed-form equations and are directly usable for medling computations. The procedures to obtain these parameters are shown and may be used for the evaluation of other materials. The results of the tests show that the activation energies of the two materials are: 4630 cal/mole for the 985B-626 materials and 4791 cal/mole for the HST-7B-112 sample no. 10 Graphite Exoxy. The outgassing rates of these materials are in the 10E-5 g/sq cm/hr range and they decay according to a power of time of 0.60 at 25 C, indicating that the outgassing process is mainly a diffusion at that temperature. The normalized mass losses versus time obtained from these tests were compared to the discrete results obtained from the ASTM-E595 tests. The comparison provides general indications on the effects of temperature and time in relation to the ASTM test values obtained at 125 C for a 24-hour test duration.

Activation of ALDH2 with Low Concentration of Ethanol Attenuates Myocardial Ischemia/Reperfusion Injury in Diabetes Rat Model

PubMed Central

Kang, Pin-Fang; Wu, Wen-Juan; Tang, Yang; Xuan, Ling; Guan, Su-Dong; Tang, Bi; Zhang, Heng

2016-01-01

The aim of this paper is to observe the change of mitochondrial aldehyde dehydrogenase 2 (ALDH2) when diabetes mellitus (DM) rat heart was subjected to ischemia/reperfusion (I/R) intervention and analyze its underlying mechanisms. DM rat hearts were subjected to 30 min regional ischemia and 120 min reperfusion in vitro and pretreated with ALDH2 activator ethanol (EtOH); cardiomyocyte in high glucose (HG) condition was pretreated with ALDH2 activator Alda-1. In control I/R group, myocardial tissue structure collapse appeared. Compared with control I/R group, left ventricular parameters, SOD activity, the level of Bcl-2/Bax mRNA, ALDH2 mRNA, and protein expressions were decreased and LDH and MDA contents were increased, meanwhile the aggravation of myocardial structure injury in DM I/R group. When DM I/R rats were pretreated with EtOH, left ventricular parameters, SOD, Bcl-2/Bax, and ALDH2 expression were increased; LDH, MDA, and myocardial structure injury were attenuated. Compared with DM + EtOH I/R group, cyanamide (ALDH2 nonspecific blocker), atractyloside (mitoPTP opener), and wortmannin (PI3K inhibitor) groups all decreased left ventricular parameters, SOD, Bcl-2/Bax, and ALDH2 and increased LDH, MDA, and myocardial injury. When cardiomyocyte was under HG condition, CCK-8 activity and ALDH2 protein expression were decreased. Alda-1 increased CCK-8 and ALDH2. Our findings suggested enhanced ALDH2 expression in diabetic I/R rats played the cardioprotective role, maybe through activating PI3K and inhibiting mitoPTP opening. PMID:27829984

Activation of ALDH2 with Low Concentration of Ethanol Attenuates Myocardial Ischemia/Reperfusion Injury in Diabetes Rat Model.

PubMed

Kang, Pin-Fang; Wu, Wen-Juan; Tang, Yang; Xuan, Ling; Guan, Su-Dong; Tang, Bi; Zhang, Heng; Gao, Qin; Wang, Hong-Ju

2016-01-01

The aim of this paper is to observe the change of mitochondrial aldehyde dehydrogenase 2 (ALDH2) when diabetes mellitus (DM) rat heart was subjected to ischemia/reperfusion (I/R) intervention and analyze its underlying mechanisms. DM rat hearts were subjected to 30 min regional ischemia and 120 min reperfusion in vitro and pretreated with ALDH2 activator ethanol (EtOH); cardiomyocyte in high glucose (HG) condition was pretreated with ALDH2 activator Alda-1. In control I/R group, myocardial tissue structure collapse appeared. Compared with control I/R group, left ventricular parameters, SOD activity, the level of Bcl-2/Bax mRNA, ALDH2 mRNA, and protein expressions were decreased and LDH and MDA contents were increased, meanwhile the aggravation of myocardial structure injury in DM I/R group. When DM I/R rats were pretreated with EtOH, left ventricular parameters, SOD, Bcl-2/Bax, and ALDH2 expression were increased; LDH, MDA, and myocardial structure injury were attenuated. Compared with DM + EtOH I/R group, cyanamide (ALDH2 nonspecific blocker), atractyloside (mitoPTP opener), and wortmannin (PI3K inhibitor) groups all decreased left ventricular parameters, SOD, Bcl-2/Bax, and ALDH2 and increased LDH, MDA, and myocardial injury. When cardiomyocyte was under HG condition, CCK-8 activity and ALDH2 protein expression were decreased. Alda-1 increased CCK-8 and ALDH2. Our findings suggested enhanced ALDH2 expression in diabetic I/R rats played the cardioprotective role, maybe through activating PI3K and inhibiting mitoPTP opening.

Therapeutic utility and medicinal chemistry of cathepsin C inhibitors.

PubMed

Guay, Daniel; Beaulieu, Christian; Percival, M David

2010-01-01

The lysosomal cysteine protease cathepsin C (Cat C), also known as dipeptidyl peptidase I, activates a number of granule-associated serine proteases with pro-inflammatory and immune functions by removal of their inhibitory N-terminal dipeptides. Thus, Cat C is a therapeutic target for the treatment of a number of inflammatory and autoimmune diseases. Cathepsin C null mice and humans with Cat C loss of function mutations (Papillon-Lefèvre syndrome) show deficiencies in disease-relevant proteases including neutrophil elastase, cathepsin G, chymases and granzymes and the Cat C mice are protected in a number of disease models. Several methodologies have been recently reported for assessing the effects of Cat C inhibitors on serine protease activities in cellular assays and prolonged treatment of rats with a reversible, selective Cat C inhibitor reduced the activity of three leukocyte serine proteases. Nearly all potent and selective Cat C inhibitors described are based on the preferred dipeptide substrates bearing either irreversible (e.g. diazomethylketone, acyloxymethyl ketone, o-acyl hydroxamic acid and vinyl sulfone) or reversible (e.g. semicarbazide, nitrile and cyanamide) electrophilic warheads. While potent and highly selective, the best inhibitors described to date still have poor stability and/or rodent pharmacokinetics, likely resulting from their peptidic nature. The lack of selective compounds with appropriate rodent pharmacokinetic properties has hampered the assessment of the effects of Cat C inhibitors on the activation of disease-relevant proteases in vivo and the full evaluation of the therapeutic utility of Cat C inhibitors.

Quantitative detection of melamine based on terahertz time-domain spectroscopy

NASA Astrophysics Data System (ADS)

Zhao, Xiaojing; Wang, Cuicui; Liu, Shangjian; Zuo, Jian; Zhou, Zihan; Zhang, Cunlin

2018-01-01

Melamine is an organic base and a trimer of cyanamide, with a 1, 3, 5-triazine skeleton. It is usually used for the production of plastics, glue and flame retardants. Melamine combines with acid and related compounds to form melamine cyanurate and related crystal structures, which have been implicated as contaminants or biomarkers in protein adulterations by lawbreakers, especially in milk powder. This paper is focused on developing an available method for quantitative detection of melamine in the fields of security inspection and nondestructive testing based on THz-TDS. Terahertz (THz) technology has promising applications for the detection and identification of materials because it exhibits the properties of spectroscopy, good penetration and safety. Terahertz time-domain spectroscopy (THz-TDS) is a key technique that is applied to spectroscopic measurement of materials based on ultrafast femtosecond laser. In this study, the melamine and its mixture with polyethylene powder in different consistence are measured using the transmission THz-TDS. And we obtained the refractive index spectra and the absorption spectrum of different concentrations of melamine on 0.2-2.8THz. In the refractive index spectra, it is obvious to see that decline trend with the decrease of concentration; and in the absorption spectrum, two peaks of melamine at 1.98THz and 2.28THz can be obtained. Based on the experimental result, the absorption coefficient and the consistence of the melamine in the mixture are determined. Finally, methods for quantitative detection of materials in the fields of nondestructive testing and quality control based on THz-TDS have been studied.

Role of aldehyde dehydrogenase in hypoxic vasodilator effects of nitrite in rats and humans

PubMed Central

Arif, Sayqa; Borgognone, Alessandra; Lin, Erica Lai-Sze; O'Sullivan, Aine G; Sharma, Vishal; Drury, Nigel E; Menon, Ashvini; Nightingale, Peter; Mascaro, Jorge; Bonser, Robert S; Horowitz, John D; Feelisch, Martin; Frenneaux, Michael P; Madhani, Melanie

2015-01-01

Background and Purpose Hypoxic conditions favour the reduction of nitrite to nitric oxide (NO) to elicit vasodilatation, but the mechanism(s) responsible for bioconversion remains ill defined. In the present study, we assess the role of aldehyde dehydrogenase 2 (ALDH2) in nitrite bioactivation under normoxia and hypoxia in the rat and human vasculature. Experimental Approach The role of ALDH2 in vascular responses to nitrite was studied using rat thoracic aorta and gluteal subcutaneous fat resistance vessels from patients with heart failure (HF; 16 patients) in vitro and by measurement of changes in forearm blood flow (FBF) during intra-arterial nitrite infusion (21 patients) in vivo. Specifically, we investigated the effects of (i) ALDH2 inhibition by cyanamide or propionaldehyde and the (ii) tolerance-independent inactivation of ALDH2 by glyceryl trinitrate (GTN) on the vasodilator activity of nitrite. In each setting, nitrite effects were measured via evaluation of the concentration–response relationship under normoxic and hypoxic conditions in the absence or presence of ALDH2 inhibitors. Key Results Both in rat aorta and human resistance vessels, dilatation to nitrite was diminished following ALDH2 inhibition, in particular under hypoxia. In humans there was a non-significant trend towards attenuation of nitrite-mediated increases in FBF. Conclusions and Implications In human and rat vascular tissue in vitro, hypoxic nitrite-mediated vasodilatation involves ALDH2. In patients with HF in vivo, the role of this enzyme in nitrite bioactivation is at the most, modest, suggesting the involvement of other more important mechanisms. PMID:25754766

Solar-Driven Reduction of Aqueous Protons Coupled to Selective Alcohol Oxidation with a Carbon Nitride-Molecular Ni Catalyst System.

PubMed

Kasap, Hatice; Caputo, Christine A; Martindale, Benjamin C M; Godin, Robert; Lau, Vincent Wing-Hei; Lotsch, Bettina V; Durrant, James R; Reisner, Erwin

2016-07-27

Solar water-splitting represents an important strategy toward production of the storable and renewable fuel hydrogen. The water oxidation half-reaction typically proceeds with poor efficiency and produces the unprofitable and often damaging product, O2. Herein, we demonstrate an alternative approach and couple solar H2 generation with value-added organic substrate oxidation. Solar irradiation of a cyanamide surface-functionalized melon-type carbon nitride ((NCN)CNx) and a molecular nickel(II) bis(diphosphine) H2-evolution catalyst (NiP) enabled the production of H2 with concomitant selective oxidation of benzylic alcohols to aldehydes in high yield under purely aqueous conditions, at room temperature and ambient pressure. This one-pot system maintained its activity over 24 h, generating products in 1:1 stoichiometry, separated in the gas and solution phases. The (NCN)CNx-NiP system showed an activity of 763 μmol (g CNx)(-1) h(-1) toward H2 and aldehyde production, a Ni-based turnover frequency of 76 h(-1), and an external quantum efficiency of 15% (λ = 360 ± 10 nm). This precious metal-free and nontoxic photocatalytic system displays better performance than an analogous system containing platinum instead of NiP. Transient absorption spectroscopy revealed that the photoactivity of (NCN)CNx is due to efficient substrate oxidation of the material, which outweighs possible charge recombination compared to the nonfunctionalized melon-type carbon nitride. Photoexcited (NCN)CNx in the presence of an organic substrate can accumulate ultralong-lived "trapped electrons", which allow for fuel generation in the dark. The artificial photosynthetic system thereby catalyzes a closed redox cycle showing 100% atom economy and generates two value-added products, a solar chemical, and solar fuel.

Prebiotic Lipidic Amphiphiles and Condensing Agents on the Early Earth

PubMed Central

Fiore, Michele; Strazewski, Peter

2016-01-01

It is still uncertain how the first minimal cellular systems evolved to the complexity required for life to begin, but it is obvious that the role of amphiphilic compounds in the origin of life is one of huge relevance. Over the last four decades a number of studies have demonstrated how amphiphilic molecules can be synthesized under plausibly prebiotic conditions. The majority of these experiments also gave evidence for the ability of so formed amphiphiles to assemble in closed membranes of vesicles that, in principle, could have compartmented first biological processes on early Earth, including the emergence of self-replicating systems. For a competitive selection of the best performing molecular replicators to become operative, some kind of bounded units capable of harboring them are indispensable. Without the competition between dynamic populations of different compartments, life itself could not be distinguished from an otherwise disparate array or network of molecular interactions. In this review, we describe experiments that demonstrate how different prebiotically-available building blocks can become precursors of phospholipids that form vesicles. We discuss the experimental conditions that resemble plausibly those of the early Earth (or elsewhere) and consider the analytical methods that were used to characterize synthetic products. Two brief sections focus on phosphorylating agents, catalysts and coupling agents with particular attention given to their geochemical context. In Section 5, we describe how condensing agents such as cyanamide and urea can promote the abiotic synthesis of phospholipids. We conclude the review by reflecting on future studies of phospholipid compartments, particularly, on evolvable chemical systems that include giant vesicles composed of different lipidic amphiphiles. PMID:27043635

Thermochemistry, Tautomerism, and Thermal Decomposition of 1,5-Diaminotetrazole: A High-Level ab Initio Study.

PubMed

Shakhova, Margarita V; Muravyev, Nikita V; Gritsan, Nina P; Kiselev, Vitaly G

2018-04-19

Thermochemistry, kinetics, and mechanism of thermal decomposition of 1,5-diaminotetrazole (DAT), a widely used "building block" of nitrogen-rich energetic compounds, were studied theoretically at a high and reliable level of theory (viz., using the explicitly correlated CCSD(T)-F12/aug-cc-pVTZ procedure). Quantum chemical calculations provided detailed insight into the thermolysis mechanism of DAT missing in the existing literature. Moreover, several contradictory assumptions on the mechanism and key intermediates of thermolysis were resolved. The unimolecular primary decomposition reactions of the seven isomers of DAT were studied in the gas phase and in the melt using a simplified model of the latter. The two-step reaction of N 2 elimination from the diamino tautomer was found to be the primary decomposition process of DAT in the gas phase and melt. The effective Arrhenius parameters of this process were calculated to be E a = 43.4 kcal mol -1 and log( A/s -1 ) = 15.2 in a good agreement with the experimental values. Contrary to the existing literature data, all other decomposition channels of DAT isomers turned out to be kinetically unimportant. Apart from this, a new primary decomposition channel yielding N 2 , cyanamide, and 1,1-diazene was found for some H-bonded dimers of DAT. We also determined a reliable and mutually consistent set of thermochemical values for DAT (Δ f H solid 0 = 74.5 ± 1.5 kcal·mol -1 ) by combining theoretically calculated (W1 multilevel procedure along with an isodesmic reaction) gas phase enthalpy of formation (Δ f H gas 0 = 100.7 ± 1.0 kcal·mol -1 ) and experimentally measured sublimation enthalpy (Δ sub H 0 = 26.2 ± 0.5 kcal·mol -1 ).

Degradation of Adenine on the Martian Surface in the Presence of Perchlorates and Ionizing Radiation: A Reflectron Time-of-flight Mass Spectrometric Study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Góbi, Sándor; Bergantini, Alexandre; Kaiser, Ralf I., E-mail: ralfk@hawaii.edu

The aim of the present work is to unravel the radiolytic decomposition of adenine (C{sub 5}H{sub 5}N{sub 5}) under conditions relevant to the Martian surface. Being the fundamental building block of (deoxy)ribonucleic acids, the possibility of survival of this biomolecule on the Martian surface is of primary importance to the astrobiology community. Here, neat adenine and adenine–magnesium perchlorate mixtures were prepared and irradiated with energetic electrons that simulate the secondary electrons originating from the interaction of the galactic cosmic rays with the Martian surface. Perchlorates were added to the samples since they are abundant—and therefore relevant oxidizers on the surfacemore » of Mars—and they have been previously shown to facilitate the radiolysis of organics such as glycine. The degradation of the samples were monitored in situ via Fourier transformation infrared spectroscopy and the electron ionization quadruple mass spectrometric method; temperature-programmed desorption profiles were then collected by means of the state-of-the-art single photon photoionization reflectron time-of-flight mass spectrometry (PI-ReTOF-MS), allowing for the detection of the species subliming from the sample. The results showed that perchlorates do increase the destruction rate of adenine by opening alternative reaction channels, including the concurrent radiolysis/oxidation of the sample. This new pathway provides a plethora of different radiolysis products that were identified for the first time. These are carbon dioxide (CO{sub 2}), isocyanic acid (HNCO), isocyanate (OCN{sup −}), carbon monoxide (CO), and nitrogen monoxide (NO); an oxidation product containing carbonyl groups (R{sub 1}R{sub 2}–C=O) with a constrained five-membered cyclic structure could also be observed. Cyanamide (H{sub 2}N–C≡N) was detected in both irradiated samples as well.« less

Hot atoms in cosmic chemistry.

PubMed

Rossler, K; Jung, H J; Nebeling, B

1984-01-01

High energy chemical reactions and atom molecule interactions might be important for cosmic chemistry with respect to the accelerated species in solar wind, cosmic rays, colliding gas and dust clouds and secondary knock-on particles in solids. "Hot" atoms with energies ranging from a few eV to some MeV can be generated via nuclear reactions and consequent recoil processes. The chemical fate of the radioactive atoms can be followed by radiochemical methods (radio GC or HPLC). Hot atom chemistry may serve for laboratory simulation of the reactions of energetic species with gaseous or solid interstellar matter. Due to the effective measurement of 10(8)-10(10) atoms only it covers a low to medium dose regime and may add to the studies of ion implantation which due to the optical methods applied are necessarily in the high dose regime. Experimental results are given for the systems: C/H2O (gas), C/H2O (solid, 77 K), N/CH4 (solid, 77K) and C/NH3 (solid, 77 K). Nuclear reactions used for the generation of 2 to 3 MeV atoms are: N(p,alpha) 11C, 16O(p,alpha pn) 11C and 12C(d,n) 13N with 8 to 45 MeV protons or deuterons from a cyclotron. Typical reactions products are: CO, CO2, CH4, CH2O, CH3OH, HCOOH, NH3, CH3NH2, cyanamide, formamidine, guanidine etc. Products of hot reactions in solids are more complex than in corresponding gaseous systems, which underlines the importance of solid state reactions for the build-up of precursors for biomolecules in space. As one of the major mechanisms for product formation, the simultaneous or fast consecutive reactions of a hot carbon with two target molecules (reaction complex) is discussed.

Degradation of Adenine on the Martian Surface in the Presence of Perchlorates and Ionizing Radiation: A Reflectron Time-of-flight Mass Spectrometric Study

NASA Astrophysics Data System (ADS)

Góbi, Sándor; Bergantini, Alexandre; Kaiser, Ralf I.

2017-04-01

The aim of the present work is to unravel the radiolytic decomposition of adenine (C5H5N5) under conditions relevant to the Martian surface. Being the fundamental building block of (deoxy)ribonucleic acids, the possibility of survival of this biomolecule on the Martian surface is of primary importance to the astrobiology community. Here, neat adenine and adenine-magnesium perchlorate mixtures were prepared and irradiated with energetic electrons that simulate the secondary electrons originating from the interaction of the galactic cosmic rays with the Martian surface. Perchlorates were added to the samples since they are abundant—and therefore relevant oxidizers on the surface of Mars—and they have been previously shown to facilitate the radiolysis of organics such as glycine. The degradation of the samples were monitored in situ via Fourier transformation infrared spectroscopy and the electron ionization quadruple mass spectrometric method; temperature-programmed desorption profiles were then collected by means of the state-of-the-art single photon photoionization reflectron time-of-flight mass spectrometry (PI-ReTOF-MS), allowing for the detection of the species subliming from the sample. The results showed that perchlorates do increase the destruction rate of adenine by opening alternative reaction channels, including the concurrent radiolysis/oxidation of the sample. This new pathway provides a plethora of different radiolysis products that were identified for the first time. These are carbon dioxide (CO2), isocyanic acid (HNCO), isocyanate (OCN-), carbon monoxide (CO), and nitrogen monoxide (NO); an oxidation product containing carbonyl groups (R1R2-C=O) with a constrained five-membered cyclic structure could also be observed. Cyanamide (H2N-C≡N) was detected in both irradiated samples as well.

Rapid detection of economic adulterants in fresh milk by liquid chromatography-tandem mass spectrometry.

PubMed

Abernethy, Grant; Higgs, Kerianne

2013-05-03

A method to aid in the detection of the economically driven adulteration of fresh milk with a range of small, nitrogen containing compounds, including melamine, ammeline, ammelide, cyanuric acid, allantoin, thiourea, urea, biuret, triuret, semicarbazide, aminotriazine, 3- and 4-aminotriazole, cyanamide, dicyandiamide, guanidine, choline, hydroxyproline, nitrate, and a range of amino acids, has been developed. (15)N2-Urea is used as an internal standard. The adulteration of milk with exogenous urea has previously been difficult to detect because of the variation in the naturally occurring levels of urea in milk. However, by monitoring the contaminants biuret and triuret, which comprise up to 1% of synthetic urea, the adulteration of milk with urea-based fertilizer can be detected. We estimate that to be economically viable, adulteration of the order of 90-4000ppm of the above adulterants would need to be added to fresh milk. For most of the compounds, an arbitrary detection threshold of 2ppm is therefore more than sufficient. For biuret, a lower detection threshold, better than 0.5ppm, is desirable and the sensitivity for biuret and triuret can be improved by the post-column addition of lithium to create lithium adducts under electrospray ionisation. Sample handling involves a two-step solvent precipitation method that is deployed in a 96-well plate format, and the hydrophilic interaction liquid chromatography uses a rapid gradient (1.2min). Three separate injections, to detect the positively charged compounds, the negatively charged compounds and amino acids and finally the lithium adducts, are used. This rapid and qualitative survey method may be deployed as a second tier screening method to quickly reduce sample numbers indicated as irregular by an FTIR based screening system, and to direct analysis to appropriate quantification methods. Copyright © 2013 Elsevier B.V. All rights reserved.

Somatostatin type-2 receptor activation inhibits glutamate release and prevents status epilepticus

PubMed Central

Kozhemyakin, Maxim; Rajasekaran, Karthik; Todorovic, Marko S.; Kowalski, Samuel L.; Balint, Corinne; Kapur, Jaideep

2013-01-01

Summary Newer therapies are needed for the treatment of status epilepticus (SE) refractory to benzodiazepines. Enhanced glutamatergic neurotransmission leads to SE, and AMPA receptors are modified during SE. Reducing glutamate release during SE is a potential approach to terminate SE. The neuropeptide somatostatin (SST) is proposed to diminish presynaptic glutamate release by activating SST type-2 receptors (SST2R). SST exerts an anticonvulsant action in some experimental models of seizures. Here, we investigated the mechanism of action of SST on excitatory synaptic transmission at the Schaffer collateral-CA1 synapses and the ability of SST to treat SE in rats using patch-clamp electrophysiology and video-EEG monitoring of seizures. SST reduced action potential-dependent EPSCs (sEPSCs) at Schaffer collateral-CA1 synapses at concentrations up to 1 μM; higher concentrations had no effect or increased the sEPSC frequency. SST also prevented paired-pulse facilitation of evoked EPSCs and did not alter action-potential-independent miniature EPSCs (mEPSCs). The effect of SST on EPSCs was inhibited by the SST2R antagonist cyanamid-154806 and was mimicked by the SST2R agonists, octreotide and lanreotide. Both SST and octreotide reduced the firing rate of CA1 pyramidal neurons. Intraventricular administration of SST, within a range of doses, either prevented or attenuated pilocarpine-induced SE or delayed the median time to the first grade 5 seizure by 11 min. Similarly, octreotide or lanreotide prevented or attenuated SE in more than 65% of animals. Compared to the pilocarpine model, octreotide was highly potent in preventing or attenuating continuous hippocampal stimulation-induced SE in all animals within 60 min of SE onset. Our results demonstrate that SST, through the activation of SST2Rs, diminishes presynaptic glutamate release and attenuates SE. PMID:23473742

On the surface chemistry of molybdena-alumina catalysts prepared from Mo(CO) sub 6

DOE Office of Scientific and Technical Information (OSTI.GOV)

Goldwasser, J.; Fang, S.M.; Houalla, M.

1989-01-01

Catalysts were prepared by subliming Mo(CO){sub 6} onto partially dehydroxylated (PDA) and exhaustively dehydroxylated (DA) alumina made from the same parent preparation (American Cyanamid Aero 100PHF). The chemisorption of NO and Co on these materials was studied using volumetric, chromatographic, and spectroscopic techniques. ESCA data indicated that metallic Mo crystals formed on Mo(CO){sub 6}/DA whereas on PDA both Mo{sup 4+} and some lower valence state, Mo{sup 2+} or Mo{sup 0}, were present. NO chemisorbed on both preparations at 195 K without releasing either N{sub 2}O or N{sub 2}. The chemisorption on the PDA preparations was over tenfold higher than thatmore » on the DA-supported catalysts under these conditions, but at 300 K the difference was reduced to a factor of 2. Moreover, redox chemistry occurred at this higher temperature as evidenced by the release of N{sub 2}O and N{sub 2}. The amounts of NO actually chemisorbed correlated well with the integrated IR band intensities. These data suggest that lower valence states are oxidized to Mo{sup 4+} at 300 K and that the observed IR bands stem from Mo{sup 4+}(NO){sub 2}, irrespective of the initial catalyst. Infrared spectra from residual CO remaining on decomposition of Mo(CO){sub 6} on DA and PDA showed bands which could be attributed to residual Mo(CO){sub 6} and/or to subcarbonyl species formed during decomposition. By 573 K, no residual bands could be observed. On adding-back CO at 300 K to the PDA preparation, bands at 1989 and 2170 cm{sup {minus}1} appeared, suggesting the presence of Mo{sup 4+} and residual Mo{sup 0}. Spectra from similar experiments with the DA preparation demonstrated that chemisorbed Mo(CO){sub 6} was reforming and possibly some subcarbonyl species.« less

Cytochromes P450 Catalyze the Reduction of α,β-Unsaturated Aldehydes

PubMed Central

Amunom, Immaculate; Dieter, Laura J.; Tamasi, Viola; Cai, Jan; Conklin, Daniel J.; Srivastava, Sanjay; Martin, Martha V.; Guengerich, F. Peter; Prough, Russell A.

2011-01-01

The metabolism of α,β-unsaturated aldehydes, e.g. 4-hydroxynonenal, involves oxidation to carboxylic acids, reduction to alcohols, and glutathionylation to eventually form mercapturide conjugates. Recently we demonstrated that P450s can oxidize aldehydes to carboxylic acids, a reaction previously thought to involve aldehyde dehydrogenase. When recombinant cytochrome P450 3A4 was incubated with 4-hydroxynonenal, O2, and NADPH, several products were produced, including 1,4-dihydroxynonene (DHN), 4-hydroxy-2-nonenoic acid (HNA), and an unknown metabolite. Several P450s catalyzed the reduction reaction in the order (human) P450 2B6 ≅ P450 3A4 > P450 1A2 > P450 2J2 > (mouse) P450 2c29. Other P450s did not catalyze the reduction reaction (human P450 2E1 & rabbit P450 2B4). Metabolism by isolated rat hepatocytes showed that HNA formation was inhibited by cyanamide, while DHN formation was not affected. Troleandomycin increased HNA production 1.6-fold while inhibiting DHN formation, suggesting that P450 3A11 is a major enzyme involved in rat hepatic clearance of 4-HNE. A fluorescent assay was developed using 9-anthracenealdehyde to measure both reactions. Feeding mice diet containing t-butylated hydroxyanisole increased the level of both activities with hepatic microsomal fractions, but not proportionally. Miconazole (0.5 mM) was a potent inhibitor of these microsomal reduction reactions, while phenytoin and α-naphthoflavone (both at 0.5 mM) were partial inhibitors, suggesting the role of multiple P450 enzymes. The oxidative metabolism of these aldehydes was inhibited >90% in an Ar or CO atmosphere, while the reductive reactions were not greatly affected. These results suggest that P450s are significant catalysts of reduction of α,β-unsaturated aldehydes in liver. PMID:21766881

Citral reduces breast tumor growth by inhibiting the cancer stem cell marker ALDH1A3.

PubMed

Thomas, Margaret Lois; de Antueno, Roberto; Coyle, Krysta Mila; Sultan, Mohammad; Cruickshank, Brianne Marie; Giacomantonio, Michael Anthony; Giacomantonio, Carman Anthony; Duncan, Roy; Marcato, Paola

2016-11-01

Breast cancer stem cells (CSCs) can be identified by increased Aldefluor fluorescence caused by increased expression of aldehyde dehydrogenase 1A3 (ALDH1A3), as well as ALDH1A1 and ALDH2. In addition to being a CSC marker, ALDH1A3 regulates gene expression via retinoic acid (RA) signaling and plays a key role in the progression and chemotherapy resistance of cancer. Therefore, ALDH1A3 represents a druggable anti-cancer target of interest. Since to date, there are no characterized ALDH1A3 isoform inhibitors, drugs that were previously described as inhibiting the activity of other ALDH isoforms were tested for anti-ALDH1A3 activity. Twelve drugs (3-hydroxy-dl-kynurenine, benomyl, citral, chloral hydrate, cyanamide, daidzin, DEAB, disulfiram, gossypol, kynurenic acid, molinate, and pargyline) were compared for their efficacy in inducing apoptosis and reducing ALDH1A3, ALDH1A1 and ALDH2-associated Aldefluor fluorescence in breast cancer cells. Citral was identified as the best inhibitor of ALDH1A3, reducing the Aldefluor fluorescence in breast cancer cell lines and in a patient-derived tumor xenograft. Nanoparticle encapsulated citral specifically reduced the enhanced tumor growth of MDA-MB-231 cells overexpressing ALDH1A3. To determine the potential mechanisms of citral-mediated tumor growth inhibition, we performed cell proliferation, clonogenic, and gene expression assays. Citral reduced ALDH1A3-mediated colony formation and expression of ALDH1A3-inducible genes. In conclusion, citral is an effective ALDH1A3 inhibitor and is able to block ALDH1A3-mediated breast tumor growth, potentially via blocking its colony forming and gene expression regulation activity. The promise of ALDH1A3 inhibitors as adjuvant therapies for patients with tumors that have a large population of high-ALDH1A3 CSCs is discussed. Crown Copyright © 2016. Published by Elsevier B.V. All rights reserved.

Cross-linked g-C3 N4 /rGO nanocomposites with tunable band structure and enhanced visible light photocatalytic activity.

PubMed

Li, Yibing; Zhang, Haimin; Liu, Porun; Wang, Dan; Li, Ying; Zhao, Huijun

2013-10-11

Cross-linked rather than non-covalently bonded graphitic carbon nitride (g-C3 N4 )/reduced graphene oxide (rGO) nanocomposites with tunable band structures have been successfully fabricated by thermal treatment of a mixture of cyanamide and graphene oxide with different weight ratios. The experimental results indicate that compared to pure g-C3 N4 , the fabricated CN/rGO nanocomposites show narrowed bandgaps with an increased in the rGO ratio. Furthermore, the band structure of the CN/rGO nanocomposites can be readily tuned by simply controlling the weight ratio of the rGO. It is found that an appropriate rGO ratio in nanocomposite leads to a noticeable positively shifted valence band edge potential, meaning an increased oxidation power. The tunable band structure of the CN/rGO nanocomposites can be ascribed to the formation of C-O-C covalent bonding between the rGO and g-C3 N4 layers, which is experimentally confirmed by Fourier transform infrared (FT-IR) and X-ray photoelectron (XPS) data. The resulting nanocomposites are evaluated as photocatalysts by photocatalytic degradation of rhodamine B (RhB) and 4-nitrophenol under visible light irradiation (λ > 400 nm). The results demonstrate that the photocatalytic activities of the CN/rGO nanocomposites are strongly influenced by rGO ratio. With a rGO ratio of 2.5%, the CN/rGO-2.5% nanocomposite exhibits the highest photocatalytic efficiency, which is almost 3.0 and 2.7 times that of pure g-C3 N4 toward photocatalytic degradation of RhB and 4-nitrophenol, respectively. This improved photocatalytic activity could be attributed to the improved visible light utilization, oxidation power, and electron transport property, due to the significantly narrowed bandgap, positively shifted valence band-edge potential, and enhanced electronic conductivity. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Solid state and dynamic solution structures of O-carbamidine amidoximes gives further insight into the mechanism of zinc(II)-mediated generation of 1,2,4-oxadiazoles

NASA Astrophysics Data System (ADS)

Kulish, Kirill I.; Novikov, Alexander S.; Tolstoy, Peter M.; Bolotin, Dmitrii S.; Bokach, Nadezhda A.; Zolotarev, Andrey A.; Kukushkin, Vadim Yu.

2016-05-01

Three new iminium salts [H2Ndbnd C(R)ONdbnd C(R‧)NH2](p-TolSO3)·½H2O ([1-3](p-TolSO3)·½H2O; R/R‧ = NMe2/PhCH21, NMe2/p-BrC6H42, N(CH2)5/p-BrC6H43) were synthesized via ZnII-mediated amidoxime-cyanamide coupling and their solid structures were studied by X-ray diffraction. Solution structure and conformational changes of [1-3](p-TolSO3)·½H2O were studied by dynamic NMR. The obtained quantitative data were supported by DFT calculations. All the obtained results help to understand the relative stability of the salts [H2Ndbnd C(R)ONdbnd C(R‧)NH2](X) (R = NAlk2, Alk, Ar) and give a further insight into the mechanism of ZnII-mediated generation of 1,2,4-oxadiazoles. The electron delocalization and sesquialteral bonds in the [H2Ndbnd C(NR2)ONdbnd C(R‧)NH2]+ system was recognized by estimation of values of activation energy barriers (14-18 kcal/mol by DNMR and 16-17 kcal/mol by DFT calculations) for the rotation around the CN bonds for the NR2 groups and inspection of the solid-state X-ray data along with the Wiberg bond indices (intermediate single/double bond order for the CN distances). This electron delocalization is responsible for the stabilization of the positively charged iminium cation. The moderate strength hydrogen bonding between the oxime N atom and the =NH2 group, which is verified from the X-ray, DNMR experiments, and by using quantum chemical calculations, stabilizes the iminium salt, but it is still weak to prevent the heterocyclization. Theoretical calculations of the heterocyclization of [H2Ndbnd C(R)ONdbnd C(R‧)NH2]+ to 1,2,4-oxadiazoles demonstrated that it is kinetically hindered to a greater extent for R = NAlk2 and this explains their lower reactivity as compared to the iminium salts with R = Alk, Ar.

Mineral Grains, Dimples, and Hot Volcanic Organic Streams: Dynamic Geological Backstage of Macromolecular Evolution.

PubMed

Skoblikow, Nikolai E; Zimin, Andrei A

2018-04-01

The hypothesis of hot volcanic organic stream as the most probable and geologically plausible environment for abiogenic polycondensation is proposed. The primary synthesis of organic compounds is considered as result of an explosive volcanic (perhaps, meteorite-induced) eruption. The eruption was accompanied by a shock wave propagating in the primeval atmosphere and resulting in the formation of hot cloud of simple organic compounds-aldehydes, alcohols, amines, amino alcohols, nitriles, and amino acids-products, which are usually obtained under the artificial conditions in the spark-discharge experiments. The subsequent cooling of the organic cloud resulted in a gradual condensation and a serial precipitation of organic compounds (in order of decreasing boiling point values) into the liquid phase forming a hot, viscous and muddy organic stream (named "lithorheos"). That stream-even if the time of its existence was short-is considered here as a geologically plausible environment for abiogenic polycondensation. The substances successively prevailing in such a stream were cyanamide, acetamide, formamide, glycolonitrile, acetonitrile. An important role was played by mineral (especially, phosphate-containing) grains (named "lithosomes"), whose surface was modified with heterocyclic nitrogen compounds synthesized in the course of eruption. When such grains got into hot organic streams, their surface catalytic centers (named "lithozymes") played a decisive role in the emergence, facilitation and maintenance of prebiotic reactions and key processes characteristic of living systems. Owing to its cascade structure, the stream was a factor underlying the formation of mineral-polymeric aggregates (named "lithocytes") in the small natural streambed cavities (dimples)-as well as a factor of their further spread within larger geological locations which played a role of chemo-ecological niches. All three main stages of prebiotic evolution (primary organic synthesis

Photochemical Generation of H_{2}NCNX, H_{2}NNCX, H_{2}NC(NX) (x = O, s) in Low-Temperature Matrices

NASA Astrophysics Data System (ADS)

Voros, Tamas; Lajgut, Gyozo Gyorgy; Magyarfalvi, Gabor; Tarczay, Gyorgy

2017-06-01

The [NH_{2}, C, N, O] and the [NH_{2}, C, N, S] systems were investigated by quantum-chemical computations and matrix-isolation spectroscopic methods. The equilibrium structures of the isomers and their relative energies were determined by CCSD(T) method. This was followed by the computation of the harmonic and anharmonic vibrational wavenumbers, infrared intensities, relative Raman activities and UV excitation energies. These computed data were used to assist the identification of products obtained by UV laser photolysis of 3,4-diaminofurazan, 3,4-diaminothiadiazole and 1,2,4-thiadiazole-3,5-diamine in low-temperature Ar and Kr matrices. Experimentally, first the precursors were studied by matrix-isolation IR and UV spectroscopic methods. Based on these UV spectra, different wavelengths were selected for photolysis. The irradiations, carried out by a tunable UV laser-light source, resulted in the decomposition of the precursors, and in the appearance of new bands in the IR spectra. Some of these bands were assigned to cyanamide (H_{2}NCN) and its isomer, the carbodiimide molecule (HNCNH), generated from H_{2}NCN. By the analysis of the relative absorbance vs. photolysis time curves, the other bands were grouped to three different species both for the O- and the S-containing systems. In the case of the O-containing isomers, these bands were assigned to the H_{2}NNCO:H_{2}NCN, and H_{2}NCNO:H_{2}NCN complexes, and to the ring-structure H_{2}NC(NO) isomer. In a similar way, the complexes of H_{2}NNCS and H_{2}NCNS with the H_{2}NCN, and H_{2}NC(NS) were also identified. 1,2,4-thiadiazole-3,5-diamine was also investigated in similar way like the above mentioned precursors. The results of this study also support the identification of the new S-containing isomers. Except for H_{2}NNCO and H_{2}NCNS, these molecules were not identified previously. It is expected that at least some of these species, like the methyl isocyanate (CH_{3}CNO) isomer, are present and could be

Did the Pre-RNA World Rest Upon DNA Molecules?

NASA Technical Reports Server (NTRS)

Lazcano, Antonio; Dworkin, Jason P.; Miller, Stanley L.

2004-01-01

The isolation of a DNA sequence that catalyzes the ligation of oligodeoxynucleotides via the formation of 3' - 5' phosphodiester linkage significance in selection experiments has been reported. Ball recently used this to discuss the possibility that natural DNA molecules may have formed in the primitive Earth leading to the origin of life. As noted by Ferris and Usher, if metabolic pathways evolved backwards, it could be argued that the biosynthesis of 2-deoxyribose from ribose suggests that RNA came from DNA. As summarized elsewhere, there are several properties of deoxyribose which could be interpreted to support the possibility that DNA-like molecules arose prior to the RNA world. For example, 2-deoxyribose is slightly more soluble than ribose (which may have been an advantage in a drying pool scenario), may have been more reactive under possible prebiotic conditions (it forms a nucleoside approx. 150 times faster than ribose with the alternative base urazole at 25 C), while it decomposes in solution (approximately 2.6 times more slowly than ribose at 100 C). Other advantages of DNA over RNA are that it has one fewer chiral center, has a greater stability at the 8.2 pH value of the current oceans, and does not has the 2'5' and 3'5' ambiguity in polymerizations. Yet, there is strong molecular biological and biochemical evidence that RNA was featured in the biology well before the last common ancestor. The presence of sugar acids, including both ribo- and deoxysugar acids, in the 4.6 Ga old Murchison meteorite suggest that both may have been available in the primitive Earth, derived from the accretion of extraterrestrial sources and/or from endogenous processes involving formaldehyde and its derivatives. However, the abiotic synthesis of deoxyribose, ribose, and other sugars from glyceraldehyde and acetaldehyde under alkaline conditions is inefficient and unespecific. Although sugars are labile compounds, the role of cyanamide or borate minerals in the

Hydrologic monitoring of a waste-injection well near Milton, Florida, June 1975 - June 1977

USGS Publications Warehouse

Pascale, Charles A.; Martin, J.B.

1978-01-01

This report presents the hydraulic and chemical data collected from June 1, 1975, when injection began, to June 30, 1977 through a monitoring program at a deep-well waste-injection system at the American Cyanamid Company's plant near Milton, about 12 miles northwest of Pensacola. The injection system consists of a primary injection well, a standby injection well, and two deep monitor wells all completed open hole in the lower limestone of the Floridan aquifer and one shallow-monitor well completed in the upper limestone of the Floridan aquifer. Two of the monitor wells and the standby injection well are used to observe hydraulic and geochemical effects of waste injection in the injection zone at locations 8,180 feet northeast, 1,560 feet south, and 1,025 feet southwest of the primary injection well. The shallow-monitor well, used to observe any effects in the first permeable zone above the 200-foot-thick confining bed, is 28 feet north of the primary injection well. Since injection began in June 1975, 607 million gallons of treated industrial liquid waste with a pH of 4.6 to 6.3 and containing high concentrations of nitrate, organic nitrogen and carbon have been injected into a saline-water-filled limestone aquifer. Wellhead pressure at the injection well in June 1977 average 137 pounds per square inch and the hydraulic pressure gradient was 0.53 pound per square inch per foot of depth to the top of the injection zone. Water levels rose from 36 to 74 feet at the three wells used to monitor the injection zone during the 25-month period. The water level in the shallow-monitor well declined about 8 feet. No changes were detected in the chemical character of water from the shallow-monitor well and deep-monitor well-north. Increases in concentration of bicarbonate and dissolved organic carbon were detected in water from the deep-test monitor well in February 1976 and at the standby injection well in August 1976. In addition to increases in bicarbonate and dissolved