Abstract  We investigated the stimulating effect of dietary fiber on fecal excretion of PCDF and PCDD stored in the rat body. Twenty-eight male rats (71-74g body weight) were orally administered with 1ml of the causal rice oil of Yusho desease. The rice oil was contaminated with 2, 3, 4, 7, 8-pentaCDF (691.4ng), 1, 2, 3, 4, 7, 8-hexaCDF (708.6ng), 1, 2, 3, 6, 7, 8-hexaCDF (128.4ng), 1, 2, 3, 7, 8-pentaCDD (7.2ng), 1, 2, 3, 6, 7, 8-hexaCDD (34.1ng), 1, 2, 3, 7, 8, 9-hexaCDD (20.1ng) and 1, 2, 3, 4, 6, 7, 8-heptaCDD (115.9ng). The animals were fed a control diet containing 10% cellulose for seven days. Twenty-eight rats consisting of four rats a group were housed and rats of each group were given a treatment diet containing 10% rice-bran-fiber (RBF), 5% cholestyramine, 10% RBF + 5% cholestyramine, 10% RBF + 5% cholestyramine + 1% squalane, 10% burdock-fiber, 10% corn-fiber and 10% soybean-fiber during a period from eight to twenty-one days. The remaining four rats served as controls. PCDF and PCDD in feces, liver, small intestine and gastrointestinal tract were analyzed by high resolution gas chromatography-mass spectrometry. PCDF level in small intestine of rats administered with RBF + cholestyramine showed a decrease of 40% over the level of control rats.(ABSTRACT TRUNCATED AT 250 WORDS)

Abstract  We discuss molecular simulation methods for computing the phase coexistence properties of complex molecules. The strategies that we pursue are histogram-based approaches in which thermodynamic properties are related to relevant probability distributions. We first outline grand canonical and isothermal-isobaric methods for directly locating a saturation point at a given temperature. In the former case, we show how reservoir and growth expanded ensemble techniques can be used to facilitate the creation and insertion of complex molecules within a grand canonical simulation. We next focus on grand canonical and isothermal-isobaric temperature expanded ensemble techniques that provide a means to trace saturation lines over a wide range of temperatures. To demonstrate the utility of the strategies introduced here, we present phase coexistence data for a series of molecules, including n-octane, cyclohexane, water, 1-propanol, squalane, and pyrene. Overall, we find the direct grand canonical approach to be the most effective means to directly locate a coexistence point at a given temperature and the isothermal-isobaric temperature expanded ensemble scheme to provide the most effective means to follow a saturation curve to low temperature.

Abstract  Mannose derivatives were synthesized as low molecular-weight gelators with various alkoxy substituents on the aromatic ring of methyl-4,6-O-benzilidene-alpha-D-mannopyranoside. Most of these mannose derivatives could gel in various solvents, such as octane, cyclohexane, toluene, ethylene glycol and ethanol solutions, at concentrations lower than 2.0 wt%. In particular, the critical gelation concentration (CGC) of methyl-4,6-O-(4-butoxybenzylidene)-alpha-D-mannopyranoside (2) for squalane was only 0.025 wt%, one of the lowest CGCs we have ever experienced. The observations of xerogels by FE-SEM, TEM and AFM revealed that the length of the alkoxy chains of the mannose derivatives influences the gel morphologies. Moreover, the toluene gels formed from the mannose derivatives 1-6 functionalized by a linear alkoxy group exhibited thixotropic properties. Interestingly, the gels of various solvents formed from methyl-4,6-O-(4-dodecyloxybenzylidene)-alpha-D-mannopyranoside (6) (with the longest alkoxy chain on the aromatic ring in this paper) exhibited thixotropic properties. Thus, we confirmed that alkoxy groups on the aromatic ring exert noticeable effects on the gelation properties of these mannose derivatives.

Abstract  MARY spectroscopy is finding increasing use in the studies of transient organic radical ions and their reactions. Extending this technique to organometallic species will broaden the class of potential target compounds and can help answer important mechanistic questions in organometallic and spin chemistry. We probed this approach using a tailored Zn(hfac)(2)(PPO)(2) complex. The synthesized complex has quantum yield and fluorescence lifetime (n-decane solution) phi similar to 0.8 and tau similar to 1.3 ns, respectively. For this type of complex it is the first observation of MARY spectra different from those of free ligand, thus implying participation of the complex in the development of the observed signal. (C) 2011 Elsevier B. V. All rights reserved.

Abstract  Colloidal GaP nanowires (NWs) were synthesized on a large scale by a surfactant-free, self-seeded solution-liquid-solid (SLS) method using triethylgallium and tris(trimethylsilyl)phosphine as precursors and a noncoordinating squalane solvent. Ga nanoscale droplets were generated in situ by thermal decomposition of the Ga precursor and subsequently promoted the NW growth. The GaP NWs were not intentionally doped and showed a positive open-circuit photovoltage based on photoelectrochemical measurements. Purified GaP NWs were used for visible-light-driven water splitting. Upon photodeposition of Pt nanoparticles on the wire surfaces, significantly enhanced hydrogen production was observed. The results indicate that colloidal surfactant-free GaP NWs combined with potent surface electrocatalysts could serve as promising photocathodes for artificial photosynthesis.

Abstract  Gelatin capsules containing squalane partially purified bone morphogenetic protein (BMP) complex were placed on the perimuscular membrane of rats. Two kinds of control, gelatin capsules containing only BMP and those bearing squalane only, were used. The embedded areas were histopathologically examined at 3 and 6 wk after the operation. The observations revealed that the squalane/BMP complex elicited wide heterotopic bone formation with bone marrow tissue, suggesting that squalane is a possible carrier of BMP for clinical applications.

Abstract  Over the past several years, we have conducted a variety of elastic neutron diffraction and quasielastic neutron scattering experiments to study the structure and the dynamics of films of two intermediate-length alkane molecules (C sub( n)H sub(2n+2)), adsorbed on a graphite basal-plane surface. The two molecules are the normal alkane n-tetracosane [n-CH sub( 3)(CH sub(2)) sub(22)CH sub(3)] and the branched alkane squalane (C sub(30)H sub(62) or 2, 6, 10, 15, 19, 23-hexamethyltetracosane) whose carbon backbone is the same length as teteracosane. The temperature dependence of the monolayer structure of tetracosane and squalane was investigated using elastic neutron diffraction and evidence of two phase transitions was observed. Both the low-coverage tetracosane (C sub( 24)H sub(50)) and squalane (C sub(30)H sub(62)) monolayers have crystalline-to-"smectic" and "smectic"-to-isotropic fluid phase transitions upon heating. The diffusive motion in the tetracosane and squalane monolayers has been investigated by quasielastic neutron scattering. Two different quasielastic neutron scattering spectrometers at the Center for Neutron Research, National Institute of Standards and Technology (NIST) have been used. The spectrometers differ in both their dynamic range and energy resolution allowing molecular motions to be investigated on time scales in the range 10 super(-13)--10 super( -9) s. On these time scales, we observe evidence of translational, rotational, and intermolecular diffusive motions in the tetracosane and squalane monolayers. We conclude that the molecular diffusive motion in the two monolayers is qualitatively similar. Thus, despite the three methyl sidegroups at each end of the squalane molecule, its monolayer structure, phase transitions, and dynamics are qualitatively similar to that of a monolayer of the unbranched tetracosane molecules. With the higher resolution spectrometer at NIST, we have also investigated the molecular diffusive motion in multilayer tetracosane films. The analysis of our measurements indicates slower diffusive motion in the bottom layer of a bilayer tetracosane film compared to that in a monolayer, while the rate of diffusive motion in the bottom two layers of the trilayer film is comparable to that in a monolayer.

Abstract  Squalane is obtained by hydrogenation from squalene, an unsaturated terpene hydrocarbon found mainly in shark liver oil. It is a very stable liquid, and has a remarkably low capacity to irritate the skin. Squalane is used as an important component in various kinds of cosmetics and has a considerably beneficial effect on faecal excretion of the highly toxic 2, 3, 4, 7, 8-pentachlorodibenzofuran (PenCDF). The distribution, excretion and subacute toxicity of squalane after oral administration has already been examined. We considered that squalane, applied subcutaneously, might be an effective carrier of drugs. Furthermore, we found an application of squalane as a carrier of bone morphogenetic protein (BMP). As there were no data on the tissue reaction to squalane administered subcutaneously, we decided to make a histopathological evaluation of squalane fluid in vivo (DBO).

Abstract  In the previous papers, we demonstrated, by using rats, that squalane (2,6,10,15,19,23-hexamethyltetracosane) could stimulate the fecal excretion of 2,3,4,7,8-pentachlorodibenzofuran, which was regarded as the most important etiologic agent of yusho among PCB and PCDF congeners found in the causal rice oil. We also reported that, in rats, squalane was not essentially absorbed from the gastrointestinal tract, and did not show any appreciable side effects during the 3-month treatment. In the present paper, we have investigated the distribution, excretion and subacute toxicity of squalane in beagle dogs. The fecal excretion of squalane accounted for about 83% of dose during the initial 2 days after administration at a single oral dose of 1,200 mg/kg to male dogs. On day 3, absorbed squalane was mostly distributed to the hair and the skin, and the concentrations in these tissues were decreased on day 6. These results suggested that most of squalane administered orally was not absorbed from the gastrointestinal tract, but a part was absorbed and excreted through the hair. In addition, squalane distributed into the liver was found to be eliminated rather slowly. A long-term (13-week) treatments with squalane orally at doses of 400 mg/kg/day or 1,200 mg/kg/day in male and female dogs, resulted also in accumulation of squalane in the liver at a level of about 3% (400 mg/kg) or about 6% (1,200 mg/kg) of the daily dose. This accumulation of squalane in the liver was highest among all the tissues. Nevertheless, no appreciable toxic signs were observed in the serum biochemical tests and the hepatic functional test for squalane groups. Therefore, squalane accumulating in the liver, did not seem to disturb the hepatic physiological functions. It was suggested also in a long-term treatment that the skin and the hair played the most important role in the elimination of squalane. In conclusion, the present studies on subacute toxicity tests suggested that squalane did not give any significant toxic effects on dogs as well as rats.

Abstract  Female mice were given 100 mg HCB/kg body weight i.p. and fed diets containing 0, 2.5, 5.0, and 7.5% of squalane. After 3 weeks samples of liver, blood and abdominal fat were analysed for HCB as well as for squalane. HCB concentrations were significantly lowered as compared to controls in all tissues and at all dietary concentrations of squalane to a maximum of about 36% in fat, 44% in liver and 47% in blood. The effect of squalane upon HCB concentrations was strongly dose dependent in abdominal fat. In contrast, no significant differences were seen with liver and blood between animals fed 5.0 or 7.5% of squalane. Squalane was detected in considerable amounts in the livers (50-100 ppm) but not in abdominal fat (less than 1 ppm) of mice fed squalane.

Abstract  Microfluidized squalene or squalane emulsions are efficient adjuvants, eliciting both humoral and cellular immune responses. Microfluidization stabilizes the emulsions and allows sterilization by terminal filtration. The emulsions are stable for years at ambient temperature and can be frozen. Antigens are added after emulsification so that conformational epitopes are not lost by denaturation and to facilitate manufacture. A Pluronic block copolymer can be added to the squalane or squalene emulsion. Soluble antigens administered in such emulsions generate cytotoxic T lymphocytes able to lyse target cells expressing the antigen in a genetically restricted fashion. Optionally a relatively nontoxic analog of muramyl dipeptide (MDP) or another immunomodulator can be added; however, the dose of MDP must be restricted to avoid systemic side effects in humans. Squalene or squalane emulsions without copolymers or MDP have very little toxicity and elicit potent antibody responses to several antigens in nonhuman primates. They could be used to improve a wide range of vaccines. Squalene or squalane emulsions have been administered in human cancer vaccines, with mild side effects and evidence of efficacy, in terms of both immune responses and antitumor activity.

Abstract  This study focused on an investigation into the experimental quantities inherent in the determination of partition coefficients from gas-liquid chromatographic measurements through the use of capillary columns. We prepared several squalane a (2,6,10,15,19,23-hexamethyltetracosane) a containing columns with very precisely known phase ratios and determined solute retention and hold-up times at 30, 40, 50 and 60 degree C. We calculated infinite dilution partition coefficients from the slopes of the linear regression of retention factors as a function of the reciprocal of the phase ratio by means of fundamental chromatographic equations. In order to minimize gasasolid and liquid-solid interface contributions to retention, the surface of the capillary inner wall was pretreated to guarantee a uniform coat of stationary phase. The validity of the proposed approach was first tested by estimating the partition coefficients of n-alkanes between n-pentane and n-nonane, for which compounds data from the literature were available. Then partition coefficients of sixteen aliphatic alcohols in squalane were determined at those four temperatures. We deliberately chose these highly challenging systems: alcohols in the reference paraffinic stationary phase. These solutes exhibited adsorption in the gas-liquid interface that contributed to retention. The corresponding adsorption constant values were estimated. We fully discuss here the uncertainties associated with each experimental measurement and how these fundamental determinations can be performed precisely by circumventing the main drawbacks.

Abstract  Among several bacterial species belonging to the general Gordonia, Mycobacterium, Micromonospora, Pseudomonas, and Rhodococcus, only two mycobacterial isolates, Mycobacterium fortuitum strain NF4 and the new isolate Mycobacterium ratisbonense strain SD4, which was isolated from a sewage treatment plant, were capable of utilizing the multiply branched hydrocarbon squalane (2,6,10,15,19, 23-hexamethyltetracosane) and its analogous unsaturated hydrocarbon squalene as the sole carbon source for growth. Detailed degradation studies and high-pressure liquid chromatography analysis showed a clear decrease of the concentrations of squalane and squalene during biomass increase. These results were supported by resting-cell experiments using strain SD4 and squalane or squalene as the substrate. The degradation of acyclic isoprenoids and alkanes as well as of acids derived from these compounds was also investigated. Inhibition of squalane and squalene degradation by acrylic acid indicated the possible involvement of beta-oxidation in the degradation route. To our knowledge, this is the first report demonstrating the biodegradation of squalane by using defined axenic cultures.

Abstract  1. The intestinal excretion of hexachlorobenzene (HCB) was studied in rats using the method of pendular perfusion. One and four weeks after i.p. application of 100 micrograms HCB/kg body weight segments of jejunum, ileum and colon were perfused with light liquid paraffin or squalane for 5 h. 2. The highest amount of HCB was excreted into jejunum, followed by ileum and colon. After 5 h HCB concentration in jejunal perfusion medium equals that in plasma. 3. Serosal tissue of intestinal segments contained higher HCB concentrations as compared to mucosa. 4. Paraffin treatment decreased the HCB content in both serosal and mucosal tissue of jejunum and ileum but not of colon.

Abstract  Trehalose dimycolate extracted from mycobacteria is a potent immunomodulator. Incorporation of trehalose dimycolate in a squalane-in-water emulsion leads predominantly to the formation of vesicular structures, which are observable by electron microscopy. The interaction between vesicles of trehalose dimycolate and the immunocompetent cells results in an enhancement of the host defence mechanisms and induction of non-specific resistance against viral, parasitic, and bacterial pathogens and certain tumors. A brief review of the pertinent observations is presented.

Abstract  The efficacy of a new vaccine preparation against Epstein-Barr (EB) virus was investigated in cotton-top tamarins. The vaccine consists of fast protein liquid chromatography-purified EB virus membrane antigen glycoprotein of 340 Kd (MA gp340) mixed with a synthetic muramyl dipeptide adjuvant emulsified in squalane containing a pluronic polymer; it is suitable for both scaled-up batch production and eventual administration to man. Vaccinated tamarins rapidly developed ELISA detectable high titre antibodies to MA gp340, and their sera became strongly EB virus-neutralising. After challenge with a massive 100% carcinogenic dose of EB virus, the vaccinated tamarins had a strikingly low level of circulating EB virus-carrying mononuclear cells, in contrast to a control animal, and remained entirely free of tumours. This first-generation vaccine has thus been validated in experimental animals and the way opened for a phase I human trial.

Abstract  The effect of alamethicin and its derivatives on the voltage-dependent capacitance of phosphatidylethanolamine (squalane) membranes was measured using two different methods: lock-in detection and voltage pulse. Alamethicin and its derivatives modulate the voltage-dependent capacitance at voltages lower than the voltage at which alamethicin-induced conductance is detected. The magnitude and sign of this alamethicin-induced capacitance change depends on the aqueous alamethicin concentration and the kind of alamethicin used. Our experimental data can be interpreted as a potential-dependent pseudocapacitance associated with adsorbed alamethicin. Pseudocapacitance is expressed as a function of alamethicin charge, its concentration in the bathing solution and the applied electric field. The theory describes the dependence of the capacitance on applied voltage and alamethicin concentration. When alamethicin is neutral the theory predicts no change of the voltage-dependent capacitance with either sign of applied voltage. Experimental data are consistent with the model in which alamethicin molecules interact with each other while being adsorbed to the membrane surface. The energy of this interaction depends on the alamethicin concentration.

Abstract  We have developed an adjuvant formulation (SAF) consisting of a synthetic muramyl dipeptide analogue (N-acetylmuramyl-L-threonyl-D-isoglutamine) in a squalane-Pluronic polymer emulsion. Used with a variety of antigens SAF elicits cell-mediated immunity and antibodies of protective isotypes (IgG2a in the mouse). SAF augments responses to influenza virus haemagglutinin and hepatitis B virus surface antigen. Vaccines using SAF have protected guinea pigs against genital herpes simplex virus infections and subhuman primates against Epstein-Barr virus and simian immunodeficiency virus infections. Properties of SAF are compared with those of other adjuvants, including lipopolysaccharide analogs, ISCOMs and liposomes.

Abstract  The ability of nontoxic monophosphoryl lipid A (MPL) to stimulate nonspecific resistance against viral infection was investigated. Mice pretreated intravenously with squalane-in-water emulsions of MPL, alone or in combination with other immunostimulants, were given an aerosol of influenza virus three weeks after the pretreatment. Complete protection against lethal influenza virus infection was conferred when MPL was combined with trehalose dimycolate (TDM). The protective activity of MPL plus TDM combination was corroborated by a significant reduction of the lung virus titers. Combination of lower doses of MPL with TDM extracted from Mycobacterium bovis, but not with that of M. phlei, induced significant resistance to influenza virus. Preparations containing MPL alone, or combined with mycobacterial cell wall skeleton or muramyl dipeptide, were not effective. The adjuvant activity of MPL on bivalent influenza subunit vaccine was also studied. The primary antibody responses to influenza A and influenza B antigens were enhanced by the addition of MPL and were higher than the vaccine associated with aluminum hydroxide. The adjuvant activity of MPL was confirmed by the elevated secondary response. High levels of circulating antibodies were still present in the MPL group when antibody titers in the controls were waning.

Abstract    The solute retention mechanism in gas-liquid chromatography was studied for the hydrocarbon solute-nonpolar stationary liquid phase (squalane) system. The retention volume of the solute and the specific surface area of the liquid-coated, modified alumina were determined as a function of the liquid loading. On the basis of the previous reasoning, distribution constants for the bulk solution partition and some adsorption equilibria taking part in the solute retention could be estimated. The results prove to be quite different from those of the polar liquid phases used previously: that is, squalane formed a bulk liquid layer on the modified alumina after the solid support was completely covered with the monolayer.

Abstract  Squalane and Squalene have been identified as natural components of human sebum. Both ingredients are used in a variety of cosmetics at concentrations ranging from 5 0.1 to > 504b. Animal studies indicate Squalene is slowly absorbed through the skin, while both compounds are poorly absorbed from the gastrointestinal tract. The acute animal toxicity of these ingredients by all routes is low. Both compounds are nonirritants to rabbit skin and eye at 100% concentration. Formulations containing Squalene indicate it is not a significant human skin irritant or sensitizer. limited contact sensitization tests indicate Squalene is not a significant contact allergen or irritant. It is concluded that both Squalane and Squalene are safe as cosmetic ingredients in the present practices of use and concentration.

Abstract  Molecular dynamics (MD) computer simulations are carried out for scattering of high-energy Xe atoms off liquid squalane, and the results are compared with those of molecular-beam scattering. experiments. A crude model for squalane is adopted, describing the hydrocarbon chain molecule as a sphere, and ignoring the role of internal modes. Good overall agreement is found between the results of the simulations and experiment, both for angular distributions and for trends in energy I transfer properties. In particular, excellent agreement is obtained for the dependence of the energy transfer on the deflection angle for in-plane scattering. Theory predicts less trapping events than found experimentally, probably due to the crude model adopted for the squalane molecules. The partial success of the model in predicting some properties and not others is discussed. The other main conclusions of the study are (1) The instantaneous local structure of the liquid surface is highly corrugated, giving rise to a broad annular distribution and to extensive out-of-plane scattering. (2) High-energy atoms undergo both a trapping desorption and also direct inelastic scattering, the latter. yielding information on liquid structure, (3) The angular distribution of atoms at a selected final velocity is sensitive to the local structure and dynamics of the surface. (4) The direct scattering can be conveniently interpreted in terms of contributions from single, double, and multiple collision events, these being roughly equal in relative weight. Forward scattering at grazing angle is dominated by single collisions, while double and multiple collisions have higher contribution at other directions. The double collision contribution in particular contains structural information. (5) There is a substantial yield per collision for sputtering of the squalane-like soft spheres. These results provide insight into the dynamics of gas-liquid collisions, and indicate the usefulness of beam scattering asa tool for studying liquid structure and dynamics.

Abstract  A molecular dynamics simulation is presented of a beam of neon atoms scattering off a n-hexyl thiolate self-assembled monolayer adsorbed on a Au (111) surface. Ab initio QCISD(T)/6-311 ++G** calculations, for a model system consisting of a neon atom and a methane molecule, were used to derive an accurate interaction potential between the neon projectile and the monolayer. Four initial translational energies of 1.2, 5, 20, and 40 kcal/mol and five incident angles (with respect to the surface normal) of 10, 30, 45, 60, and 80 degrees were investigated in the simulations. Both trapping desorption and direct inelastic scattering collisional events were observed. The fraction of trapping desorption decreases as the initial translational energy and/or the angle of incidence increases. For high initial translational energy, trapping desorption may involve penetration of the monolayer. The overall energy transfer probability and the fraction of trapping desorption are in good agreement with previous experiments [J. Chem. Phys. 99, 7056 (1993)] and computational studies [J. Chem. Phys. 100, 8408, 6500 (1994)] of neon atom beams colliding with Liquid squalane surfaces. There is a small but measurable change in the energy transfer efficiency for neon atoms colliding parallel versus perpendicular to the ''tilt angle'' of the SAM. The distributions of the change in the azimuthal angle and the scattering angle between the neon final velocity vector and surface normal provide additional information about the collision dynamics. A general discussion of these simulation results is given, in the context of existing models and theories for gas/surface collisions, to achieve a more fundamental understanding of the dynamics of interfaces. (C) 1997 American Institute of Physics.

Abstract  We have used friction force microscopy to probe friction laws for nanoasperities sliding on atomically flat substrates under controlled atmosphere and liquid environment, respectively. A power law relates friction force and normal load in dry air, whereas a linear relationship, i.e., Amontons' law, is observed for junctions fully immersed in model lubricants, namely, octamethylciclotetrasiloxane and squalane. Lubricated contacts display a remarkable friction reduction, with liquid and substrate specific friction coefficients. Comparison with molecular dynamics simulations suggests that load-bearing boundary layers at junction entrance cause the appearance of Amontons' law and impart atomic-scale character to the sliding process; continuum friction models are on the contrary of limited predictive power when applied to lubrication effects. An attempt is done to define general working conditions leading to the manifestation of nanoscale lubricity due to adsorbed boundary layers.