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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 19 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1989

The 3-(bromoacetamido)-propylamine hydrochloride: A novel sulfhydryl reagent and its future potential in the configurational study of S1-myosin

Configurational study of S1-Myosin is an important step towards understanding force generation in muscle contraction. Previously reported NMR studies were corroborated. A new compound was synthesized, 3-(Bromoacetamido)-propylamine hydrochloride. Its potential as a sulfhydryl reagent provides an indirect but elegant approach towards future structural elucidation of S1-Myosin. The preliminary investigation has shown that this compound, BAAP, reacted with S1 in the absence of MgADP. The modified enzyme had a 2-fold increase in CaATPase activity and no detectable K-EDTA ATPase activity. Reaction of BAAP with S1 in the presence of MgADP resulted in a modified enzyme which retained a Ca-ATPase activity that was about 60 percent of the unmodified S1 and had essentially zero K-EDTA ATPase activity. Sulfhydryl titration indicated that about 1.5 and 3.5 SH groups per S1 molecule were blocked by BAAP in the absence and presence of MgADP, respectively. When coupled to a carboxyl group of EDTA, the resulting reagent could become a useful SH reagent in which chelated paramagnetic or luminescent lanthanide ions can be exploited to probe S1 conformation.

Sharma, Prasanta↗
NASA NTRS1992

Room temperature synthesis of copper indium diselenide in non-aqueous solution using an organoindium reagent

A novel two-phase synthesis of CuInSe2 at 25 C from Cu2Se and Cp3In in 4-methylpyridine has been discovered. Characterization of the material produced shows it to be platelet-shaped crystallites with an average particle size of 10 microns, less than 2 percent C and H, with a small amount of unidentified crystalline impurity. The results demonstrate that it is possible to produce from solution a material that is ordinarily synthesized in bulk or films at much higher temperatures or using extraneous reagents and/or electrons. The use of a solid-state reagent as a starting material which is converted to another solid-state compound by an organometallic reagent has tremendous potential to produce precursors for a wide range of solid-state materials of interest to the electronics, defense, and aerospace communities.

Hepp, Aloysius F.↗
NASA NTRS1988

Slow Release Of Reagent Chemicals From Gel Matrices

Procedure developed for slow release of reagent chemicals into solutions. Simple and inexpensive and not subject to failure of equipment. Use of toothpaste-type tube or pump dispenser conceivably provides more controlled technique for storage and dispensation of gel matrix. Possible uses include controlled, slow release of reagents in chemical reactions, crystal growth, space-flight experiments, and preformed gel medications from packets.

Debnam, William J.↗
NASA NTRS1987

Effects of diatomic reagent alignment on the A + BC reaction

A computational study is reported on the A + BC - AB + C bimolecular exchange reaction in which BC is aligned with respect to the approach direction of atom A so that the initial rotational angular momentum vector of BC is either parallel (or equivalently antiparallel) or perpendicular to the initial velocity vector of A. The calculations employ a modification of the extended LEPS potential, which permits straightforward generation of noncollinear minimum energy reaction paths. The calculations clearly demonstrate that diatomic reagent alignment can markedly affect the nature of reaction product early partitioning; they also demonstrate that diatomic reagent alignment affects reactive cross sections.

Pattengill, M. D.↗
NASA NTRS2002

Chemical Amplification with Encapsulated Reagents

Autocatalysis and chemical amplification are characteristic properties of living systems, and they give rise to behaviors such as increased sensitivity, responsiveness, and self-replication. Here we report a synthetic system in which a unique form of compartmentalization leads to nonlinear, autocatalytic behavior. The compartment is a reversibly formed capsule in which a reagent is sequestered. Reaction products displace the reagent from the capsule into solution and the reaction rate is accelerated. The resulting self-regulation is sensitive to the highly selective molecular recognition properties of the capsule.

Chen, Jian↗
NASA NTRS1993

Ion mobility spectrometry of hydrazine, monomethylhydrazine, and ammonia in air with 5-nonanone reagent gas

Hydrazine (HZ) and monomethylhydrazine (MMH) in air were monitored continuously using a hand-held ion mobility spectrometer equipped with membrane inlet, 63Ni ion source, acetone reagent gas, and ambient temperature drift tube. Response characteristics included detection limit, 6 ppb; linear range, 10-600 ppb; saturated response, >2 ppm; and stable response after 15-30 min. Ammonia interfered in hydrazines detection through a product ion with the same drift time as that for MMH and HZ. Acetone reagent gas was replaced with 5-nonanone to alter drift times of product ions and separate ammonia from MMH and HZ. Patterns in mobility spectra, ion identifications from mass spectra, and fragmentation cross-sections from collisional-induced dissociations suggest that drift times are governed by ion-cluster equilibria in the drift region of the mobility spectrometer. Practical aspects including calibration, stability, and reproducibility are reported from the use of a hand-held mobility spectrometer on the space shuttle Atlantis during mission STS-37.

Flight Experiment↗
NASA NTRS2023

Evaluation of the Interference of Tenax®TA Adsorbent With Dimethylformamide Dimethyl Acetal Reagent for Gas Chromatography-Dragonfly Mass Spectrometry and Future Gas Chromatography-Mass Spectrometry in Situ Analysis

Among future space missions, national aeronautics and space administration (NASA) selected two of them to analyze the diversity in organic content within Martian and Titan soil samples using a gas chromatograph – mass spectrometer (GC–MS) instrument. The Dragonfly space mission is planned to be launched in 2027 to Titan's surface and explore the Shangri-La surface region for years. One of the main goals of this mission is to understand the past and actual abundant prebiotic chemistry on Titan, which is not well characterized yet. The ExoMars space mission is planned to be launched in 2028 to Mars’ surface and explore the Oxia Planum and Mawrth Vallis region for years. The main objectives focus on the exploration of the subsurface soil samples, potentially richer in organics, that might be relevant for the search of past life traces on Mars where irradiation does not impact the matrices and organics. One recently used sample pre-treatment for gas chromatography – mass spectrometry analysis is planned on both space missions to detect refractory organic molecules of interest for astrobiology. This pre-treatment is called derivatization and uses a chemical reagent – called dimethylformamide dimethyl acetal (DMF-DMA) – to sublimate organic compounds keeping them safe from thermal degradation and conserving the chirality of the molecules extracted from Titan or Mars’ matrices. Indeed, the detection of building blocks of life or enantiomeric excess of some organics (e.g. amino acids) after DMF-DMA pre-treatment and GC–MS analyses would be both bioindicators. The main results highlighted by our work on DMF-DMA and Tenax®TA interaction and efficiency to detect organic compounds at ppb levels in a fast and single preparation are first that Tenax®TA did not show the onset of degradation until after 150 experiments – a 120 h at 300 °C experiment – which greatly exceeds the experimental lifetimes for the DraMS and GC-space in situ investigations. Tenax®TA polymer and DMF-DMA produce many by-products (about 70 and 46, respectively, depending on the activation temperature). Further, the interaction between the two leads to the production of 22 additional by-products from DMF-DMA degradation, but these listed by-products do not prevent the detection of trace-level organic molecules after their efficient derivatization and volatilization by DMF-DMA in the oven ahead the GC–MS trap and column.

DraMS-Dragonfly mission↗
NASA NTRS1967

Tritiated alumina serves as reagent for self-labeling analysis

Tritiated alumina, prepared by exchange of the surface hydroxyl groups with tritiated water, is a suitable reagent for exchange-labeling of specific compounds in low concentrations prior to chromatographic analysis. In a chromatographic column, it detects and measures submicrogram quantities of material.

Erenrich, E. H.↗
NASA NTRS1980

Immunomicrospheres - Reagents for cell labeling and separation

Immunomicrospheres are specially designed microscopic particles that have antibodies or similar molecules chemically bound to their surfaces. The antibody-coated microspheres react in a highly specific way with target cells, viruses, or other antigenic agents. Immunomicrospheres may be synthesized so that they incorporate compounds that are highly radioactive, intensely fluorescent, magnetic, electron opaque, highly colored, or pharmacologically active. These various types of microspheres may be coated with pure, highly specific monoclonal antibodies obtained by the new hybridoma cell cloning techniques or with conventional antibody preparations. Some of the many present and potential applications for these new reagents are (1) new types of radioimmune or immunofluorescent assays, (2) improved fluorescence microscopy, (3) separation of cells on the basis of the fluorescent, electrophoretic, or magnetic properties of bound immunomicrospheres, (4) markers for use in several types of electron or standard light microscopy, and (5) delivery of lethal compouds to specific undesirable living cells. The combination of the various new types of synthetic microspheres and the newly available homogeneous antibodies offers new opportunities in research, diagnosis, and therapy.

Rembaum, A.↗
NASA NTRS1985

Remarks on preparation of indandione detection reagents

A modified Claisen condensation with sliced sodium at a higher temperature was recommended for the production of ungranulated charcoal. A new ninhydrin production method by oxidation of benzaldiketohydrinden using available reagents was tried and was unsuccessful. Triketohydrinden was obtained by boiling ninhydrin in acetic acid anhydrides.

Stepan, J.↗
NASA NTRS1994

Phenylethynyl End-Capping Reagents And Reactive Diluents

Compounds containing phenylethynyl group serve as thermally reactive polymer end caps and reactive diluents. Useful in preparation of adhesives, composite matrices, and molding compounds. These reagents transform arylene ether oligomers and polymers into readily processable reactive materials that convert thermally to thermosets. Compounds synthesized for subsequent use in making thermoset polymers. Phenylethynyl group found to offer several unexpected advantages over ethynyl-based analog.

Bryant, Robert G.↗
NASA NTRS1994

Phenylethynyl endcapping reagents and reactive diluents

A phenylethynyl composition which can be used to endcap nucleophilic species is employed in the production of phenylethynyl terminated reactive oligomers exclusively. These phenylethynyl terminated reactive oligomers display unique thermal characteristics, as exemplified by the model compound, 4-phenoxy 4'-phenylethynylbenzophenone, which is relatively stable at 200 C, but reacts at 350 C. In addition, a reactive diluent was prepared which decreases the melt viscosity of the phenylethynyl terminated oligomers and subsequently reacts therewith to increase density of the resulting thermoset. The novelty of this invention resides in the phenylethynyl composition used to terminate a nucleophilic reagent, resulting in the exclusive production of phenylethynyl terminated reactive oligomers which display unique thermal characteristics. A reactive diluent was also employed to decrease the melt viscosity of a phenylethynyl terminated reactive oligomer and to subsequently react therewith to increase the crosslink density of the resulting thermoset. These materials have features which make them attractive candidates for use as composite matrices and adhesives.

Jensen, Brian J.↗
NASA NTRS1994

Room-temperature synthesis of CuInQ2 (Q = S or Se) in non-aqueous solution using an organoindium reagent

We have discovered a novel two-phase synthesis of CuInSe2 at 25 deg C from Cu2Se and (C5H5)3In in 4-methylpyridine (4-MePy). An analogous reaction to produce CuInS2 must be run at 140 deg C in refluxing 4-MePy in the presence of 2-mercaptopyridine. Microscopy of CuInSe2 produced at 25 deg C shows it to be platelet-shaped crystallites with an approximate particle size of 10 microns, less than 2 percent C and H, with a small amount of unidentified crystalline impurity. Our results demonstrate that it is possible to produce from solution a material that is ordinarily synthesized in bulk or films at much higher temperatures or using extraneous reagents and/or electrons.

Hepp, Aloysius F.↗
NASA NTRS1994

Inhibition of the Vacuolar-like ATPase from Halobacterium saccharovorum by Thiol Reagents: Evidence for Different Functional Thiols

N-Ethylmaleimide (NEM) inhibited the vacuolar-like ATPase from Halobacterium saccharovorum (K(sub i) approximately 1 mM) by modifying one or more of the thiols located on the largest of the subunit. ATP protected against inhibition and coincidentally prevented NEM binding which suggested that NEM acts at or near the catalytic site. p-Chloromercuriphenylsulfonate (PCMS) also inhibited this ATPase (K(sub i) approximately 90 microM). ATP did not protect against PCMS inhibition. Dithiothreitol (DTT) partially reversed PCMS inhibition and restored approximately half of the initial activity of 90% inhibited enzyme. DTT did not restore activity of the NEM-inhibited enzyme or the PCMS-inhibited enzyme when it was subsequently incubated with NEM. The failure of ATP to protect against PCMS inhibition and the inability of DTT to restore activity of enzyme incubated in the presence of PCMS and NEM suggests these reagents react with different thiols and that the PCMS-sensitive thiol may have a structural role.

Hochstein, L. I.↗