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1.
Dimer structure and liquid structure of fatty acids in the binary liquid mixture of dodecanoic (LA) and 3-phenylpropionic acids (PPA) were studied through the measurements of DSC, self-diffusion coefficient (D), density, viscosity, 13C NMR spin-lattice relaxation time, small-angle X-ray scattering (SAXS), and small-angle neutron scattering (SANS). The phase diagram of LA/PPA mixture exhibited a typical eutectic pattern, which means that LA and PPA are completely immiscible in solid phase. In the liquid phase of the LA/PPA mixture, D of LA always differed from that of PPA irrespective of their compositions. This exhibited that, in the liquid phase of the binary mixture of fatty acids giving a complete eutectic in the solid phase, the fatty acid dimers are composed of the same fatty acid species irrespective of their compositions. The liquid structure of the LA/PPA mixture was clarified through the SAXS and also the SANS measurements.  相似文献   

2.
The solubilization of hydrophilic and lipophilic molecules, with biological relevance, in the monoolein/water (MO/W) system has been investigated for phase behavior. Small angle X-ray scattering (SAXS), nuclear magnetic resonance (NMR) and optical microscopy (OM) have been used to characterize the microstructure of the liquid crystalline phases. Partial phase diagrams of the MO/W system in the presence of sodium decanoate, 1-adamantanamine hydrochloride, decanoic and dodecanoic acids, acetyl salicilic acid and retinol have been determined. The stability of the various phases has been followed for at least eight months. The polarity and the molecular structure of the additive determine whether it is located at the polar interface or in the apolar region of the lipid layer. Therefore, the additive affects the interfacial curvature of the lipid layer differently, which in turn will trigger transition to disparate phases. A cubic-to-reverse hexagonal phase transition has been observed with time for most of the ternary systems, with the exception of 1-adamantanamine hydrochloride and retinol. The release of free glycerol and oleic acid due to MO hydrolysis has been clearly demonstrated by 13C NMR. This would account for the changes in phase behavior observed with time. The released oleic acid, located in the MO acyl chain region, favors the inverse interfacial curvature. The average lipid dimensions in the cubic and in the reverse hexagonal phases have been calculated from SAXS data.  相似文献   

3.
Mechanisms of proton/hydroxide conductance (GH/OH) were investigated in planar (Mueller-Rudin) bilayer membranes made from decane solutions of phospholipids or phospholipids plus phytanic acid (a 20-carbon, branched chain fatty acid). At neutral pH, membranes made from diphytanoylphosphatidylcholine or bacterial phosphatidylethanolamine had GH/OH values in the range of (2-5) X 10(-9) S X cm-2, corresponding to H+/OH- 'net' permeabilities of about (0.4-1.0) X 10(-5) cm X s-1. GH/OH was inhibited by serum albumin, phloretin, glycerol and low pH, but was increased by chlorodecane and voltage greater than 80 mV. Water permeability and GH/OH were not correlated, suggesting that water and H+/OH- cross the membrane by separate pathways. Addition of phytanic acid to the phospholipids caused an increase in GH/OH which was proportional to the first power of the phytanic acid concentration. In membranes containing phytanic acid, GH/OH was inhibited by albumin, phloretin, glycerol and low pH, but was increased by chlorodecane and voltages greater than 80 mV. The results suggest that phytanic acid acts as a simple (A- type) proton carrier. The qualitative similarities between the behavior of GH/OH in unmodified and phytanic-acid containing membranes suggest that phospholipids may contain weakly acidic contaminants which cause most of GH/OH at pH greater than 4. However, there is also a significant background (pH independent) GH/OH which may be due to hydrogen-bonded water chains. The ability of phytanic acid to act as a proton carrier may help to explain the toxicity of phytanic acid in Refsum's disease, a metabolic disorder in which phytanic acid accumulates to high levels in plasma, cells and tissues.  相似文献   

4.
Behaviour of morphocycline (H5R) and its complex with beryllium ions in acqueous solutions was studied fluorimetrically. The ionization constants of H5R were estimated at pH 1.5-15 according to the data of fluorimetric determination with respect to OH-group: pK1 6.40, pK2 8.25, pK3 10.65, pK4 11.30. Two constants characterizing the deprotonization process with respect to the carbonylic group and nitrogen were also estimated: pK01--1.0 (greater than C = 0) and pK02 4.75 (--N=). Formation of an intensively fluorescing compound less than [Be3(OH)3(H2O2)5]2HR greater than 2+ was observed at pH 6.0-7.0. The cause of such intensive fluorescence was deformation of ion [Be3(OH)3(H2O)6]3+ because of its exclusion from the coordinating sphere of one molecule of water during the complex formation and decreasing of level H comes from II as compared to the morphocycline level II comes from n. A procedure for detecting morphocycline in the blood of humans and animals was developed.  相似文献   

5.
The effect of magnetic field (MF) treatments of maize (Zea mays L.) var. Ganga Safed 2 seeds on the growth, leaf water status, photosynthesis and antioxidant enzyme system under soil water stress was investigated under greenhouse conditions. The seeds were exposed to static MFs of 100 and 200 mT for 2 and 1 h, respectively. The treated seeds were sown in sand beds for seven days and transplanted in pots that were maintained at -0.03, -0.2 and -0.4 MPa soil water potentials under greenhouse conditions. MF exposure of seeds significantly enhanced all growth parameters, compared to the control seedlings. The significant increase in root parameters in seedlings from magnetically-exposed seeds resulted in maintenance of better leaf water status in terms of increase in leaf water potential, turgor potential and relative water content. Photosynthesis, stomatal conductance and chlorophyll content increased in plants from treated seeds, compared to control under irrigated and mild stress condition. Leaves from plants of magnetically-treated seeds showed decreased levels of hydrogen peroxide and antioxidant defense system enzymes (peroxidases, catalase and superoxide dismutase) under moisture stress conditions, when compared with untreated controls. Mild stress of -0.2 MPa induced a stimulating effect on functional root parameters, especially in 200 mT treated seedlings which can be exploited profitably for rain fed conditions. Our results suggested that MF treatment (100 mT for 2 h and 200 for 1 h) of maize seeds enhanced the seedling growth, leaf water status, photosynthesis rate and lowered the antioxidant defense system of seedlings under soil water stress. Thus, pre sowing static magnetic field treatment of seeds can be effectively used for improving growth under water stress.  相似文献   

6.
Effect of the constant magnetic field (MF) by the induction of 1.1 T on formation kinetics of bilayer lipid membranes (BLM) from egg lecithin in decane was discovered. Under the effect of MF oriented in parallel to the lipid film place the rate of BLM formation decreases, while at its perpendicular orientation it is accelerated. The stationary value of BLM capacity decreases under MF effect at both orientations. The discovered changes in the rate of BLM formation under MF effect seem to be related to the effect of MF on liquid crystalline structure of colour lipid film.  相似文献   

7.
Pseudomonas MA3 was isolated from activated sludge on the basis of its capacity to use dodecyldimethylamine as a sole carbon (C) and energy source. Dodecylamine, dodecanal, dodecanoic acid and acetic acid also supported growth of Pseudomonas MA3. Dodecyldimethylamine-grown cells oxidized a wide range of alkylamine derivatives, dodecanal, dodecanoic acid and acetic acid. Degradation of the alkyl chain of dodecyldimethylamine by Pseudomonas MA3 appeared from the stoichiometric liberation of dimethylamine. A dehydrogenase catalysed the cleavage of the Calkyl-N bond. The first intermediate of the proposed degradation pathway, dodecanal, accumulated in the presence of decanal used as a competitive inhibitor. The second intermediate,dodecanoic acid, was formed in the presence of acrylic acid during the degradation of dodecyldimethylamine. Dodecanal was converted into dodecanoic acid by a dehydrogenase and dodecanoic acid was then degraded via the oxidation pathway.  相似文献   

8.
Adolescence is a critical developmental stage during which substantial remodeling occurs in brain areas involved in emotional and learning processes. Although a robust literature on the biological effects of extremely low frequency magnetic fields (ELF‐MFs) has been documented, data on the effects of ELF‐MF exposure during this period on cognitive functions remain scarce. In this study, early adolescent male mice were exposed from postnatal day (P) 23–35 to a 50 Hz MF at 2 mT for 60 min/day. On P36–45, the potential effects of the MF exposure on spatial memory performance were examined using the Y‐maze and Morris water maze tasks. The results showed that the MF exposure did not affect Y‐maze performance but improved spatial learning acquisition and memory retention in the water maze task under the present experimental conditions. Bioelectromagnetics 34:275–284, 2013. © 2012 Wiley Periodicals, Inc.  相似文献   

9.
Drop coating deposition Raman (DCDR) spectroscopy is used to obtain high-quality normal Raman spectra from small volumes (10 microl) of dilute insulin solutions (3-400 microM) for spectral identification and chromatographic detection. The results are used to demonstrate the spectroscopic classification (identification) of three natural insulin variants-human, bovine, and porcine-that differ by between one and three amino acid residues. DCDR measurements were performed on solutions obtained from reverse phase high-performance liquid chromatography (RP-HPLC) eluent fractions, either before or after lyophilization. Classification is demonstrated using replicate DCDR measurements, followed by normalized Savitsky-Golay second derivative preprocessing and partial least squares training with either leave-one-out or batch-to-batch testing.  相似文献   

10.
The aim of this study was to analyse the Raman and infrared spectra of eight common mammalian bile acids in order to identify intermolecular interactions between hydroxyl and carbonyl groups. The results are considered in the light of the new hydrophilic/hydrophobic classification of bile acids. The alcohol OH group of the hydrophobic bile acids forms different intermolecular bonds. The most hydrophobic bile acid, lithocholic acid forms polymers, and this may explain its very low water solubility. The hydrophilic bile acids have some of their alcohol OH groups free of any intermolecular interaction. The strongly hydrophilic murideoxycholic acid also forms dimers, again consistent with a very low water solubility. The proposed structural arrangements are in agreement with published crystallographic studies. Received: 7 November 1996 / Accepted: 8 December 1996  相似文献   

11.
Dimer structure and liquid structure of fatty acids in their binary mixtures such as decanoic acid (DA)/octadecanoic acid (SA) and DA/dodecanoic acid (LA) were studied through the measurements of self-diffusion coefficient (D), differential scanning calorimetry (DSC), density and viscosity. The obtained phase diagrams showed that DA and SA form a eutectic in the solid state but partly a solid solution in the SA-rich region; DA and LA form an incongruent-melting compound which forms a eutectic with DA. In the liquid mixture of DA and SA, the D of DA is larger than that of SA over the entire range of compositions and tends to approach the D of SA with increasing SA-mole fraction; the D of DA in the DA/LA system is also larger than that of LA especially in the LA-poor region and steeply approaches that of LA with increasing LA-mole fraction. These D values and phase diagrams were compared with those for the binary mixtures of n-alkanes (C14/C20, C19/C20 and C20/C24); it is concluded that the two kinds of fatty acids always form their individual homodimers in their liquid mixtures regardless of their compositions and temperatures.  相似文献   

12.
N-acetyl-L-aspartic acid (NAA) is an amino acid present in the vertebrate brain that is synthesized and stored primarily in neurons, although it cannot be hydrolyzed in these cells. Nonetheless, neuronal NAA is dynamic and turns over more than once each day by cycling, via extracellular fluids (ECF), between neurons and catabolic compartments in oligodendrocytes. One important role of the NAA intercompartmental cycle appears to be osmoregulatory, and in this role it may be the primary mechanism for the removal of metabolic water, against a water gradient, from myelinated neurons. However, the number of water molecules that might be cotransported to ECF per NAA molecule released is as yet unclear. In this investigation, using a proton nuclear magnetic resonance method and diffusion measurements at two magnetic field strengths on water and NAA phantoms in vitro, the effect of NAA on the diffusion coefficient of water has been measured, and a ratio (K) of obligated water molecules per molecule of NAA has been determined. For NAA measured at 100mM and 3 Tesla K=24 and at 7 Tesla K=14. Based on these results, apparent K(NAA) varies inversely with field strength, and with a computed field strength factor of 2.55mmol water/unit Tesla, K(NAA) in the absence of any applied magnetic field strength would be 32.  相似文献   

13.
A rapid and selective high-performance liquid chromatographic method for the simultaneous quantitative analysis of clofibric acid and probenecid in plasma and urine and for the direct analysis of clofibric acid glucuronide in plasma is described. Both methods involve direct injection of deproteinised body fluids. Concentrations of as low as 10 mg/l of clofibric acid and probenecid and 1.5 mg/l of clofibric acid glucuronide can be measured by the analysis. The coefficient of variance for these methods ranges from 1–7%.  相似文献   

14.
Incubation for 72 h of human peripheral blood cultures in the presence of 60 Hz sinusoidal magnetic fields (MF) at magnetic flux densities of 1.0, 1.5, and 2.0 mT led to stimulation of lymphocyte proliferation but had no influence on the frequency of sister-chromatid exchanges (SCE). The cytotoxic potential of MF combined with the mutagen Mitomycin-C also was analyzed. An opposite effect between MF exposure and Mitomycin-C treatment in terms of cell kinetics and mitotic rate was found, whereas no variation in SCE frequency was observed for this coexposure condition.  相似文献   

15.
The increase in crop productivity is an urgent need of the time to reduce scarcity of food in underdeveloped countries. Several biological, chemical and physical methods have been applied to promote crop yield. Application of magnetic field (MF) is an emerging physical method used to increase plant growth and yield. The reports on MF pretreatment-induced nutritional changes in harvested seeds are scarce. We previously identified the optimal frequency of MF to improve plant growth and yield as 1500 nT at 10.0 Hz. This study was aimed to investigate the effect of MF treatment on storage proteins and fatty acids in harvested soybean seeds. The results showed that MF triggered globulin production and suppressed prolamin production. However, lipid content in seeds increased, because MF exposure caused an elevation of several fatty acids including caprylic acid, palmitic acid, heptadecanoic acid, linoleic acid, lignoceric acid and eicosapentaenoic acid. This is the first report to reveal the seed pretreated MF on nutritional values of harvested seeds. This study suggests that MF treatment improves seed quality by regulating the metabolism of storage proteins and fatty acids.  相似文献   

16.
Odd numbered 1-alkenes, such as 1-pentadecene or 1,8,11,14-heptadecatetraene are formed from palmitic or linolenic acid by fragmentative decarboxylation. Incubation studies with germinating safflower (Carthamus tinctorius) and (2R,3R)-12-phenyl[2,3-2H2]dodecanoic acid, (2S,3S)-12-phenyl[2,3-2H2]dodecanoic acid, (2R)-12-phenyl[2-2H]dodecanoic acid and (2S)-12-phenyl[2-2H]dodecanoic acid instead of the natural alpha-linolenic acid precursor revealed the fragmentation to be an overall anti elimination of the 3-pro(S) hydrogen and the carboxyl group (anti-periplanar transition state geometry). Externally offered 3-hydroxy acids are not fragmented to 1-alkenes. The most probable mechanistic alternatives are in agreement with abstraction of the 3-pro(S) hydrogen as a radical followed by electron transfer and fragmentation, or transient insertion of oxygen into the 3-pro(S) C-H bond and subsequent fragmentation into an 1-alkene and CO2 after appropriate activation. The mechanism seems to be of general importance for the biosynthesis of vinylic substructures of natural products from oxygenated precursors.  相似文献   

17.
This paper presents an analysis of the excess Gibbs free energy of aqueous electrolytes. The analysis of experimental data leads to the conclusion that the equilibrium state for dilute univalent electrolytes in water involves an intercalation of water and ionic liquid crystal domains. Excess free energy of the solution is determined by the Madelung energy of hydrated ion-pair liquid crystals, and the energy associated with a shift in the structural equilibrium of water. The data that point to such a model include: molecular orbital-molecular dynamics applied to electrolyte water systems; Raman spectra; infrared spectra; magnetic resonance spectra of ions; the apparent density of water; and the excess free energy of electrolytes in aqueous solutions. Molecular orbital-molecular dynamics calculations of relatively large water clusters containing a molecule of sodium iodide show that the solvent separated ion pair exists in a substantial potential well compared to other possible structures. Raman spectra of univalent electrolyte solutions as a function of concentration can be quantitatively modeled using only the spectra of pure water and electrolyte solution at the concentration of the solvent separated ion pair. The other observations are consistent with the structures proposed from the Raman spectral study. The new model provides a satisfactory account of the fact that the excess free energy of dilute (<0.2 mol/l) solutions is generally more negative than anticipated on the basis of Debye-Hückel theory, and that the equilibrium evidence points to the same functional behavior at very low concentrations as is seen at 0.05 mol/l. We present a testable hypothesis that the excess free energy, and other thermodynamic properties of the solutions do not follow the Debye-Hückel limiting law. The tests of this hypothesis must involve only equilibrium measurements at concentrations between 0.05 and 0.0005 mol/l. This hypothesis concerning the structure of aqueous electrolyte solutions is not in conflict in any way with the Debye-Hückel-Onsager theory of electrical conductivity.  相似文献   

18.
The effect of alternating low-frequency (50 Hz, 40 mT) magnetic field (MF) on preventing of early rejection of xenotransplants (XT) of the chicken embryo forebrain, grafted in the brain parenchyma of adults rats, was studied. For this purpose, rats with XT were treated with 1-h-long MF applications over 1, 3, and 5 days following neurotransplantation. The animals with XT, but without treatment with MF, were used as a control. Morphological analysis of XT and neighboring brain tissues of recipients was performed 5 days after transplantation. It was found that the action of MF prevented or substantially weakened reactions of XT rejection at early stages after XT grafting in the brain of recipient rats. Destruction of the neighboring brain tissues was decelerated, while in the control group of animals destructions were clearly manifested. Positive effect of MF was observed even after single 1-h-long application of MF the next day after the operation, and it did not change when MF treatment was repeated 3 or 5 times during the following days. It is suggested that MF depresses some cellular reactions, in particular migration of lymphocytes and reactive gliosis, which cause early XT rejection. A possibility that the MF effect is due to activation of immunodepressant factor and/or to blockade of antigen receptors of the main histocompatibility complex on the donor and/or recipient cell surface cannot be ruled out.  相似文献   

19.
The effect of in vivo exposure of mice to a 60 Hz sinusoidal magnetic field (MF) at 2.0 mT on male germ cells was studied. The cytological endpoints measured included meiotic chromosome aberrations in spermatocytes and sperm morphology. Three independent experiments were carried out: (a) animals exposed for 72 h, (b) 10 days/8 h daily, and (c) 72 h exposure to MF plus 5 mg/kg of Mitomycin-C. No statistically significant differences indicative of MF effects were observed between MF exposed and control animals. In addition, an opposite effect between MF exposure and Mitomycin-C treatment in terms of chromosomal aberrations and sperm morphology was observed.  相似文献   

20.
Pershin SM 《Biofizika》2010,55(4):619-625
A conception of biocommunication based on the principle of radiophysics stating that the carrier modulation takes place at the resonance frequency in the transmission-receiver system has been substantiated and proved. The coherent radiation of space OH-masers (1.6-1.7 GHz) and ortho-H2O-maser (22.3 GHz) is proposed as a source of the carrier frequency. The narrow lines of rotational transition of H2O and OH molecules in liquid water were proposed to be considered as an analog of selective resonances of transmitter and receiver in radiocommunication. The possibility of the ortho-para conversion of H2O spin isomers, induced by weak electromagnetic fields, is discussed.  相似文献   

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