Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Propane”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 271 records · Page 15Linked to original sources
PubMed2005

Infrared optical properties and AFM of spin-cast chitosan films chemically modified with 1,2 Epoxy-3-phenoxy-propane.

Chemical modification of spin-cast chitosan films has been performed. This modification involves the attachment of 1,2 Epoxy-3-phenoxy-propane, commonly known as glycidyl phenyl ether (GPE), to the amine group of the chitosan molecule. Optical properties of modified films have been determined in the infrared region of the spectrum using spectroscopic ellipsometry, and are reported in this paper. Special attention is paid to the infrared region where the index of refraction and extinction coefficients from 750 to 4000 cm(-1) were determined. Difference plots of IR optical data before and after chemical modification were generated to confirm that modification had occurred. Optical modeling of infrared spectroscopic ellipsometry (IRSE) data with respect to chemical bond vibrations has also been performed. This modeling involved curve fitting of resonant chemical bond absorptions using Lorentz oscillators. These oscillator models allow for comparison of modified chitosan to unmodified chitosan. The purpose of this research was to determine infrared optical constants of chemically modified chitosan films This work shows that surface chemistry of biomaterials can be studied quite sensitively with spectroscopy ellipsometry, detecting as little as 100 ng/cm(2) of GPE.

Adsorption↗
PubMed2006

Synthesis and evaluation of novel 1-(1H-1,2,4-triazol-1-yl)-2-(2,4-difluorophenyl)-3-[(4-substitutedphenyl)-piperazin-1-yl]-propan-2-ols as antifungal agents.

A series of 1-(1H-1,2,4-triazol-1-yl)-2-(2,4-difluorophenyl)-3-[(4-substitutedphenyl)-piperazin-1-yl]-propan-2-ols have been designed and synthesized on the basis of the structure-activity relationships and antimycotic mechanism of azole antifungal agents. Their structures were confirmed by elemental analysis, IR, MS, (1)H NMR and (13)C NMR. Results of preliminary antifungal tests against six human pathogenic fungi (Candida albicans, Candida parapsilosis, Cryptococcus neoformans, Candida tropicalis, inherently fluconazole-resistant Candida krusei, Candida glabrata) in vitro showed that all title compounds exhibited activity against fungi tested to some extent except against C. tropicalis. Compound 5b showed higher activity against C. albicans, C. parapsilosis and C. krusei than fluconazole, and its MIC values were determined to be 0.5microg/mL, 1microg/mL and 4microg/mL, respectively. Compound 5k showed higher activities against Torulopsis glabrata than fluconazole (with the MIC value of 2microg/mL). Compounds 5a, 5c, 5f, 5g, 5i exhibited higher activities against C. parapsilosis than fluconazole (with the MIC values of 2microg/mL, 2microg/mL, 2microg/mL, 1microg/mL and 2microg/mL, respectively).

Antifungal Agents↗
PubMed2005

In vivo protection of synaptosomes by ferulic acid ethyl ester (FAEE) from oxidative stress mediated by 2,2-azobis(2-amidino-propane)dihydrochloride (AAPH) or Fe(2+)/H(2)O(2): insight into mechanisms of neuroprotection and relevance to oxidative stress-related neurodegenerative disorders.

Ferulic acid ethyl ester (FAEE) is an ester derivative of ferulic acid, the latter known for its anti-inflammatory and antioxidant properties. Previous studies from our laboratory have shown that ferulic acid protects synaptosomal membrane system and neuronal cell culture systems against hydroxyl and peroxyl radical oxidation. FAEE is lipophilic and is able to penetrate lipid bilayer. Previous studies reported that FAEE reduces Alzheimer's amyloid beta peptide Abeta(1-42)-induced oxidative stress and cytotoxicity in neuronal cell culture by direct radical scavenging and by inducing certain antioxidant proteins. In the present study we tested the hypothesis that FAEE would provide neuroprotection against free radical oxidative stress in vivo. Synaptosomes were isolated from the gerbils that were previously injected intraperitoneally (i.p.) with FAEE or DMSO and were treated with oxidants, Fe(2+)/H(2)O(2) or 2,2-azobis(2-amidino-propane)dihydrochloride (AAPH). Synaptosomes isolated from the gerbil previously injected i.p. with FAEE and treated with Fe(2+)/H(2)O(2) and AAPH showed significant reduction in reactive oxygen species (ROS), levels of protein carbonyl, protein bound 4-hydroxynonenal (HNE, a lipid peroxidation product), and 3-nitrotyrosine (3-NT, another marker of protein oxidation formed by reaction of tyrosine residues with peroxynitrite) compared to Fe(2+)/H(2)O(2) or AAPH induced oxidative stress in synapotosomes isolated from the brain of gerbils that were previously injected with DMSO. The synaptosomes isolated from gerbil pre-injected with FAEE and subsequently treated with AAPH or Fe(2+)/H(2)O(2) showed induction of heme oxygenase (HO-1) and heat shock protein 70 (HSP-70) but reduced inducible nitric oxide synthase (iNOS) levels. These results are discussed with reference to potential use of this lipophilic antioxidant phenolic compound in the treatment of oxidative stress-related neurodegenerative disorders.

Aldehydes↗
PubMed2005

Raman spectrum, conformational stability, barriers to internal rotations and DFT calculations of 1,1,1-trifluoro-propane-2-thione with double-internal-symmetric rotor.

The Raman spectrum (3500-100 cm-1) of 1,1,1-trifluoro-propane-2-thione (TFPT), CF3C(S)CH3 of the solid phase has been recorded. The internal rotation of CH3 and/or CF3 moieties around CC bonds in TFPT allow five hypothetical conformers (Cs and C1 point groups). Aided by quantum chemical (QC) calculations, the Cc conformer is the only stable form (CF3 and CH3 groups are eclipsing the CS bond) which contains a planar FCC(S)CH backbone and possess intramolecular hydrogen sulfur interactions. However, other conformations (with the orientation of sulfur atom being trans to either hydrogen or fluorine atom) are either transition states or not fully converged geometry with "gauche" orientation. Moreover, the calculation were carried out at the level of Becke three Lee-Yan-Parr (B3LYP) parameters up to 6-311++G(d,p) basis sets. The torsional barriers are adequately described by a three-fold potential, V3 which have been determined utilizing the optimized structural parameters from the B3LYP/6-31G(d) basis set along with potential surface scan. Barriers of 1.28 kcal/mol (448 cm-1) and 1.94 kcal/mol (678 cm-1) were calculated for CH3 and CF3 symmetric rotors, respectively. Complete vibrational assignments have been reported for the stable Cc isomer which is supported by normal coordinate analysis and potential energy distributions (PEDs) for all fundamentals. Moreover, equilibrium geometries, vibrational frequencies are compared to the corresponding experimental values of acetone, 1,1,1-trifluoroacetone (TFA), hexafluoroacetone (HFA) and other molecules having the CF3 moiety whenever appropriate.

Fluorine↗
PubMed2006

Synthesis, molecular structure, spectroscopic studies and second-order nonlinear optical behaviour of N,N'-(2-hydroxy-propane-1,3-diyl)-bis(5-nitrosalicylaldiminato-N,O)-copper(II).

N,N'-(2-Hydroxy-propane-1,3-diyl)-bis(5-nitrosalicylaldiminato-N,O)-copper(II) has been synthesized. The crystal structure has been determined by X-ray diffraction analysis, and linear optical characterization has been determined by UV-vis spectroscopy. It was found that the molecule under investigation has solvatochromic behaviour in the UV region, implying non-zero microscopic first hyperpolarizability. To reveal the microscopic nonlinear optical (NLO) properties, the static first hyperpolarizabilities (beta) and the electric dipole moments (mu) were evaluated by using the ab initio finite field (FF) method. According to the results of the FF calculations, the synthesized compound exhibits non-zero beta values, and it might have microscopic NLO behaviour.

Copper↗
PubMed1998

Synthesis of alpha,alpha-, alpha,Beta-, and Beta,Beta-(dimaltoside)s of ethane-1,2-diol, propane-1,3-diol, and butane-1,4-diol: a proposal for an initial adhesion mode.

Nine dimaltoside derivatives of ethane-1,2-diol, propane-1,3-diol, and butane-1,4-diol having the alpha,alpha, alpha,beta, and beta,beta anomeric configurations at the linkage sites have been synthesized. Suitably protected maltosyl halides or a 1-(phenylthio) derivative were condensed with the foregoing diols and the resulting monomaltosyl derivatives were further condensed with the maltosyl donors to give, after deprotection, the title compounds. Their structures were fully characterized by NMR spectroscopy. Interactions between the three alpha,alpha-(dimaltoside)s and cinnamyl alcohol are briefly discussed.

Carbohydrate Conformation↗
PubMed2003

Vitrification of ECV304 cell suspensions using solutions containing propane-1,2-diol and trehalose.

In this paper, we report on the suitability of solutions containing propane-1,2-diol (propylene glycol, PD), sugars, and salts for the vitrification of the human cell line, ECV304. Cooling (at 10 degrees C/min) and rewarming (at 80 degrees C/min) were at rates that are practicable for the tissues to be studied later. Under these conditions, 45% PD in phosphate-buffered saline (PBS) sometimes froze during cooling and always devitrified during rewarming but both events were avoided if the PBS salts were replaced by an osmotically equivalent concentration of sucrose or trehalose. The effect of such solutions on cells was evaluated using a cell culture assay in which the number of cells recovered after 3 days of culture was divided by the number cells plated, giving a cell multiplication factor or CMF. In the absence of PD the cells tolerated a low-salt concentration in solutions that were made isotonic with sugars, but they recovered poorly when 45% PD was also present. Trehalose gave significantly better recovery than sucrose. When 39% PD and 15% trehalose were included in a low-salt vehicle solution (LSV) that contained approximately 5% of the total salt concentration of PBS (this solution was designated LSV/39/15), the cells exhibited approximately 40% of untreated control CMF following exposure for 9min. LSV/39/15 vitrifies with a glass transition temperature of -102 degrees C, does not devitrify when warmed at 80 degrees C/min, and has suitable dielectric properties for uniform and rapid dielectric heating. An improved method for adding and removing LSV/39/15 gave a CMF of approximately 55% of untreated controls. Using this method, 1.0ml suspensions of ECV304 cells was cooled to, and stored briefly at, -120 degrees C and then rewarmed by immersion in a 37 degrees C water bath ( approximately 75 degrees C/min). The CMF of the cooled samples was similar to that of the exposure-only controls, approximately 50% of the untreated control CMF in both cases.

Calorimetry, Differential Scanning↗
PubMed1978

Animal experiments on the compensation of the immunosuppressive action of cyclophosphamide by 2-[-2-cyanaziridinyl-(1)-]-2-[-2-carbamoylaziridinyl-(1)]-propane BM 12 531.

BM U2 531, the 2-[2-Cyanaziridinyl-(1)-]-2-[-2-carbamoylaziridinyl-(1)-]-propane, the further development of BM 06 002 is able to compensate the immunosuppressive action of Cyclophosphamide and to increase the carcinostatic action of Cyclophosphamide. These properties are demonstrated 1. by a leucocytosis induced after application of BM 12 531 in rats 2. by a quick restauration of leucocyte depression induced by Cyclophosphamide in rats and dogs 3. by an increase of resistance against an infection (candida albicans) in mice 4. by an increase of antitumour effect of Cyclophosphamide against a DS-carcinosarcoma in rats.

Animals↗
PubMed2001

Enzymes involved in the glycidaldehyde (2,3-epoxy-propanal) oxidation step in the kinetic resolution of racemic glycidol (2,3-epoxy-1-propanol) by Acetobacter pasteurianus.

It is already known that kinetic resolution of racemic glycidol (2,3-epoxy-1-propanol) takes place when Acetobacter pasteurianus oxidizes the compound to glycidic acid (2,3-epoxy-propionic acid) with glycidaldehyde (2,3-epoxy-propanal) proposed to be the transient seen in this conversion. Since inhibition affects the feasibility of a process based on this conversion in a negative sense, and the chemical reactivity of glycidaldehyde predicts that it could be the cause for the phenomena observed, it is important to know which enzyme(s) oxidise(s) this compound. To study this, rac.- as well as (R)-glycidaldehyde were prepared by chemical synthesis and analytical methods developed for their determination. It appears that purified quinohemoprotein alcohol dehydrogenase (QH-ADH type II), the enzyme responsible for the kinetic resolution of rac.-glycidol, also catalyses the oxidation of glycidaldehyde. In addition, a preparation exhibiting dye-linked aldehyde dehydrogenase activity for acetaldehyde, most probably originating from molybdohemoprotein aldehyde dehydrogenase (ALDH), which has been described for other Acetic acid bacteria, oxidised glycidaldehyde as well with a preference for the (R)-enantiomer, the selectivity quantified by an enantiomeric ratio (E) value of 7. From a comparison of the apparent kinetic parameter values of QH-ADH and ALDH, it is concluded that ALDH is mainly responsible for the removal of glycidaldehyde in conversions of glycidol catalysed by A. pasteurianus cells. It is shown that the transient observed in rac.-glycidol conversion by whole cells, is indeed (R)-glycidaldehyde. Since both QH-ADH and ALDH are responsible for vinegar production from ethanol by Acetobacters, growth and induction conditions optimal for this process seem also suited to yield cells with high catalytic performance with respect to kinetic resolution of glycidol and prevention of formation of inhibitory concentrations glycidaldehyde.

Journal Article↗
PubMed1998

Cellular expression of inducible nitric oxide synthase following rat cortical incision and its suppression by hydroxyl radical scavenger, 1,2-bis(nicotinamido)propane.

Cellular expression of an inducible isoform of nitric oxide synthase (iNOS) was studied immunohistochemically 1,3 and 7 days following rat cortical incision. The induction of iNOS was demonstrated almost exclusively in the macrophages accumulated within the incision cavity on day 3. They were significantly reduced in number by the treatment with 1,2-bis(nicotinamido)propane (P < 0.01), suggesting the involvement of hydroxyl radicals in the macrophage activation after cortical injury.

Animals↗
PubMed1986

Quantitative determination of N-[trans-2-(dimethylamino)-cyclopentyl]-N-(3',4'-dichlorophenyl)propan amide, its 2H5-labeled analogue and their N-dealkylated metabolites in dog serum by capillary gas chromatography-mass spectrometry.

This paper describes the development of a capillary gas chromatographic--mass spectrometric method for the determination of N-[trans-2-(dimethylamino)cyclopentyl]-N-(3',4'-dichlorophenyl)propan amide and its metabolites in serum. The method utilizes an automated sample preparation whereby drug, metabolites and internal standard are extracted from polar serum components by adsorption chromatography onto an XAD-type resin. The N-demethylated metabolites are derivatized by acetylation prior to chromatography. Detection is by mass spectrometry with chemical ionization. This method was utilized to determine levels of unlabeled and pentadeuterated drug and their respective metabolites in canine serum after oral co-administration. No significant kinetic isotope effects were observed for either absorption or metabolism.

Animals↗
PubMed2002

Biofilm formation in Escherichia coli is affected by 3-(N-morpholino)propane sulfonate (MOPS).

In most natural environments, association with a surface in a structure known as a biofilm is the prevailing microbial life-style. Escherichia coli has been a useful model for the study of biofilm formation. Here we analyzed the amounts of biofilm formed when E. coli was cultured in the presence of MOPS [3-(N-morpholino)propane sulfonatel. We used the "O'Toole and Kolter" method, which consisted of growing cells in PVC microtiter dishes and staining the formed biofilm with crystal violet. Our results showed that: 1) the addition of 100 mM MOPS to the rich Luria-Bertani (LB) medium increased the capacity of biofilm formation of several E. coli strains; and 2) the biofilm formed by cells growing in the presence of MOPS was more evident and well defined than that of cells cultured in LB-only medium. The improved ability of forming biofilms was maintained even for 60 h after removing MOPS from the medium, indicating that this improvement was due to a change in the metabolism of E. coli growing in the presence of MOPS or that, under these conditions, biofilm formation was favored.

Biofilms↗
PubMed2000

Effect of 1-(gamma)linolenyl-3-eicosapentaenoyl propane diol on the growth of human pancreatic carcinoma in vitro and in vivo.

Essential fatty acids such as (gamma)linolenic (GLA) and eicosapentaenoic (EPA) acids have been proposed as anticancer drugs. The aim of this study was to test the effect of a lipid emulsion containing both GLA and EPA in a novel chemical formulation of 1-(gamma)linolenyl-3-eicosapentaenoyl propane diol on the growth of human pancreatic carcinoma in vitro and in nude mice. This compound had a dose-dependent growth-inhibitory effect on human pancreatic cancer cell lines MIA PaCa-2 and Panc-1 in vitro. The concentration necessary for 50% growth inhibition was 25 micromol/l for MIA PaCa-2 and 68 micromol/l for Panc-1 (95% CI 20-29 and 59-77 micromol/l respectively). Nude mice bearing subcutaneous pancreatic tumours produced with the MIA PaCa-2 cell line were treated with the maximum tolerated dose (6.75 mg GLA and 7.3 mg EPA per g of body weight) administered over 10 days by daily intravenous (i.v.) bolus injections. No antitumour effect or major alteration in tumour lipid fatty acid composition was seen in comparison with control animals. Concurrent treatment with parenteral iron (iron saccharate, 5 microg/gram body weight daily) did not make a significant difference. Further improvements in fatty acid delivery mechanisms are necessary before they can become useful anticancer agents.

Animals↗
PubMed1998

Synthesis and anti-HIV activities of symmetrical N1,N3-dibenzyl-2-hydroxy-propane derivatives.

We report the synthesis and the anti-HIV activities of new C2-symmetrical and achiral N1,N3-dibenzyl-2-hydroxy-propane isosteres. Some of them showed significant inhibitory activity with respect to HIV-infected MT4 cells (compound 6a and 7a, IC50 = 0.1 microM). These new structurally simple compounds represent new synthons which can be suitable for combinatorial chemistry purposes.

Anti-HIV Agents↗
PubMed1997

Selective carriers of norepinephrine and ammonium ions: ionophoric properties and molecular modelling studies of diester crown compounds containing a 1,3-bis(1H-pyrazol-1-yl)propane unit.

Ionophoric properties of dipyrazolic crowns and podands containing a 1,3-bis(1H-pyrazol-1-yl)propane unit in their structure are described. They show selectivity of ammonium vs alkali cations and interesting norepinephrine transport rates. A molecular modelling study has been used to elucidate the superstructures of the crown and ammonium cation complexes.

Esters↗
PubMed2003

A PGSE study of propane gas flow through model porous bead packs.

We present a study of the probability density for molecular displacements of gas flowing through bead packs. The three bead packs to be described are composed of polydispersed porous PVC particles, 500 microm glass spheres, and 300 microm polystyrene spheres. A range of velocities (1 cm s(-1) to 1 m s(-1)) and observation times (3-500 ms), hence transport distances, are presented. For comparison we also measure the propagators for water flow in the polystyrene sphere pack. The exchange time between the moving and the stagnant portions of the flow is a strong function of the diffusion coefficient of the fluid. Comparing the propagators between water and propane flowing in similar porous media makes this clear. The gas propagators, for flowing and diffusing molecules, consistently show a feature at the average pore diameter. This feature has previously been observed for similar Peclet number studies in smaller monodispersed bead packs using liquids, but is now demonstrated for larger beads with gas. We analyze and discuss these propagators in the physically intuitive propagator space and also in the well-understood Fourier q space. The extension of NMR PGSE experiments to gas systems allows flow and diffusion information to be obtained over a wider range of length and time scales than with liquids, and also for a new range of physical environments and systems. Interactions between stochastic and deterministic motion are fundamental to the theoretical description of transport in porous media, and the time and length scale dependences are central to an understanding of the resultant dispersive motion.

Journal Article↗
PubMed1983

The sterilizing capacity of propylene oxide and chlorhexidine diacetate solutions upon pre-injection swabs saturated with propan-2-ol.

The sporicidal activity of two solutions which have been used in the production of 'sterile' pre-injection swabs has been investigated. Propylene oxide (3.4% w/w) and chlorhexidine diacetate (0.6% w/w), both made up in approximately 65% w/w propan-2-ol, were artificially contaminated with spores of Bacillus subtilis var. niger and swabs were impregnated with these; surviving spores were enumerated at various temperatures and times of storage. Chlorhexidine diacetate had no sporicidal activity, whereas the activity of propylene oxide was dependent on temperature. The former should not be considered a sterilant and the latter can only be considered such if a controlled incubation period at an elevated temperature is employed.

1-Propanol↗
PubMed2001

Structural and spectroscopic studies of the versatile coordination chemistry of the chiral ligand N,N-bis(1-propan-2-onyl oxime)-L-methionine N'-methylamide with Ni(II) and Zn(II).

The potentially pentadentate, chiral ligand N,N-bis(1-propan-2-onyl oxime)-L-methionine N'-methylamide (L-MABO) shows remarkable versatility in its coordination chemistry with Ni(II) and Zn(II). In the crystal structure of the ZnCl2 complex of L-MABO, the ligand coordinates to the metal only through its three nitrogen donor groups (one amine and two oximes), with two chloride anions completing the distorted trigonal bipyramidal coordination sphere. In the NiCl2 complex, the three nitrogen donors and the thioether sulfur coordinate, along with two chlorides. The crystal structure of the Ni(NO3)2 complex contains two independent molecules, one of which coordinates the three nitrogens, the thioether sulfur, and the amide oxygen of L-MABO in addition to one nitrate anion. The second molecule coordinates the three nitrogen donors, the amide oxygen, one nitrate anion, and a methanol molecule. Thus, in only three crystal structures, L-MABO demonstrates its ability to provide N3, N3S, N3O, and N3OS donor sets. The thioether-bound complexes are unusual in that they have a predominantly nitrogen environment with a nickel-thioether bond that is not constrained by surrounding donor groups in a macrocyclic or linear polydentate motif. Comparison of the thioether-coordinated and methanol-coordinated molecules in the Ni(NO3) salt of L-MABO demonstrate the effect of the thioether bond on the relative "hardness" of the nickel. The electronic absorption and circular dichroism spectra of the aqueous solutions of the nickel complexes are interpreted in terms of a "descent in symmetry" model based on successive C3v and Cs distortions from octahedral geometry. These ligand field spectra indicate that in aqueous solution all ligand groups except for the three nitrogens of L-MABO are displaced by water. In acetonitrile, the non-nitrogen donors in the nitrate salt may also be displaced, while the chlorides remain coordinated.

Journal Article↗