Abstract  Assessment of acute toxicity of squalan in rats was conduced according "guidelines for toxicity studies issued by Ministry of Health and Welfare of Japan (MHW) - 1993. The test item was administered orally to rats (male and female) at the unique dose of 2000 mg/kg and its acute toxicity was assessed. Observation period was conduced from J0 (administration) to J14. No deaths occurred throughout the observation period, no abnormality was observed and the body weight gain increased normally. Based on these results, it is concluded that the oral LDL0 (lethal dose lowest) of squalan is greater than 2 000mg/kg.

Abstract  The test has been realized according OCDE 84/449 L251 method on 10 animals (wistar rats - 5 females and 5 males). The test item was administrated by oral gavage at the unique dose of 2 ml/kg. Animals were observed from J0 (oral administration) to J14. No mortality, neither no clinical sign were observed after oral administration of 2 ml/kg. In the test conditions, the substance is considered as nontoxic after oral administration of a unique dose 2 ml/kg.

Abstract  Biological oil hydrocarbons degradation is a complicated process, influenced by hydrocarbons properties, microorganisms and environmental conditions. The aim of this work was to select microbial strain, capable of degrading heavy branched hydrocarbons for further application in environment remediation and bio-cracking. Also, it was necessary to select optimal conditions (temperature, pH, concentration and etc.) for selected microbial strain degrading heavy branched hydrocarbons. Since crude oil and its products are mixtures of various hydrocarbons, at the first step of selection the ability of the strains to degrade individual hydrocarbons was investigated. Squalane was used as a test substrate. 10 microbial cultures belonging to genus Arthrobacter and obtained from culture collection of JSC "Biocentras" were used for the investigations. Gas chromatography analysis revealed that Arthrobacter sp NJ5 strain had the highest effectiveness (67%) in degradation of heavy branched oil hydrocarbon (Squalane) to shorter chain intermediates. So, Arthrobacter sp NJ5 could be applied in bio-cracking. For the application in industry, more detailed analyses are needed.

Abstract  Tetradecane (TD), testosterone (TS), and dimethyl sulfoxide (DMSO) were separately inuncted on rabbit pinnas once a day; the pinnas were biopsied on days 1, 3, 7, and 28. Untreated pinnas and squalane-treated pinnas were used as controls. Three-dimensional images of sebaceous glands were reconstructed from their serial histologic sections using a computer-image analysis system. By stereometry, the sebaceous gland volumes gradually increased during the course of treatments with TS and DMSO, whereas the volumes of TD-treated sebaceous glands increased, reached the maximum on day 7, and then decreased. The acinus number was increased by all the substances, the DMSO-treated sebaceous glands on day 28 showing the largest number of acini. The volumes of individual acini increased until day 28 with TS treatment, whereas with TD and DMSO treatments they increased, reached the maximum on day 7, and then decreased. Stereographically, each untreated control sebaceous gland was composed of 20-30 pear-shaped acini. On day 28, acini of TS-treated sebaceous glands were swollen and ovoid in shape, DMSO-treated sebaceous glands resembled a bunch of grapes, and acini of TD-treated sebaceous glands were widely scattered and showed globular swelling arising from an elongated tube. Hyperplastic responses of sebaceous glands are quite different according to substances applied topically.

Abstract  This study investigated the removal of long-chain alkanes, which are released as the result of shipping activities and fuel oil spills, with Penicillium simplicissimum YK, a fungus that degrades polyethylene. Two branched alkanes (pristane and squalane) and a phosphoric ester (Plysurf A210G) were used separately as a dispersant. Yeast extract and malt extract were added as a supplementary nutrient, respectively, to enhance cell growth. Squalane was found to be more favorable to the long-chain n-alkane degradation than pristine when the cell density was higher. When 0.001% (w/v) Plysurf A210G was used as the dispersant and 0.3% malt extract was added as the supplementary nutrient, about 26% to 51% of an initial concentration of 0.10% (w/v) of n-alkanes 30 to 40 carbons long was degraded in two weeks. In this case, no apparent correlation was observed between the molecular weights of the long-chain n-alkanes and their degradation rates. In a separate experiment, it was confirmed that the fungus used pristane, squalane, and n-alkanes with a chain of 20 and 50 carbons long for growth. This report demonstrated the biodegradability of the long-chain straight and branched alkanes by Penicillium simplicissimum YK.

Abstract  Alkanes having unusual saturated isoprenoidal and methyl-branched structures have been isolated from the bitumen of several sediments. The methanogenic biomarkers 2,6,10,15,19-pentamethyleicosane and squalane were found in sediments which also contained bacteriogenic glycerol ethers. However, in one ether-containing sediment, 2,6,10,13,17,21 -hexamethyldocosane was tentatively identified and this compound was found in place of the established alkane biomarkers. Other hydrocarbons found were regular C21 and C23 isoprenoid alkanes, compounds which cannot be derived from phytol; two isoprenoids of the type 3,7,11 . . . -polymethylalkane, previously reported only in petroleums; 8-methylheptadecane, a probable biomarker for cyanobacteria and a number of its homologs and other methyl-branched alkanes. Ubiquitous branched-chain alkylbenzenes and a homology of trimethylalkylbenzenes were also isolated. Most, or all, of the compounds reported here are probably not catagenetic products but may represent direct algal or bacterial bioinputs.

Abstract  In this study, the molecular composition and biomarker distribution of lacustrine sediments from Val-1 drillhole in the central zone of the western part of the Valjevo-Mionica basin were investigated at depth interval of 0- 400 m. Former investigations have shown that the core material can be separated into six depth intervals based on bulk geochemical, mineralogical and sedimentological characteristics. Concerning the quality of organic matter, presence of specific minerals, and high salinity and anoxicity, or alkalinity, three zones are of highest interest, defined at depth intervals of 15-75 m (A), 75-200 m (B) and 360-400 m (F). The first aim of the study was to identify which biomarkers characterize these specific intervals. The second aim, addressing the transitions zones of these intervals, was to extend the changes in the characteristics of the organic substance, to reflect the changes of conditions in the depositional environment as well as to define biomarker parameters which are the most sensitive sedimentological indicators. The sediments from the hypersaline anoxic and alkaline environment show high contribution of algal precursor biomass, what is in accordance with the good quality of organic substances in the sediments from these zones. High squalane content and low content of regular isoprenoid C sub(25) are typical for hypersaline anoxic environment, whereas sediments from alkaline environment have high regular isoprenoid C sub(25) content. Transition to specific sedimentation zones is characterized by change in total organic matter content, and of both free and pyrolysis-derived, and change in hydrogen index value. In the biomarker distributions, more significant changes were detected in distributions of n-alkanes and isoprenoids, compared to polycyclic alkanes. The most intensive changes in alkane distribution are reflected in changes in n-C sub(17) content compared to n-C sub(27), and phytane compared to n-C sub(18). In addition, significant sensitivity was seen in ratios between squalane and n-alkane C sub(26) (hypersaline depositional environment), or isoprenoid C sub(25) and n-alkane C sub(22) for high alkalinity environment. This study showed that Sq/n-C sub(26) ratio can be used to assess the quality of organic substance in immature lacustrine sediments.

Abstract  Adjuvants can be used with recombinant antigens to elicit cell-mediated immunity and antibodies of protective isotypes (IgG2a in the mouse and IgG1 in primates). Adjuvants should not produce reactions at injection sites, be pyrogenic or induce anterior uveitis or arthritis. Among 130 analogs of muramyl dipeptides tested, N-acetylmuramyl-L-threonyl-D-isoglutamine showed the greatest separation of potency as an adjuvant from potency in the production of side-effects. A stable emulsion of squalane and the Pluronic polymer L-121 provides a versatile vehicle for targeting of antigens to antigen-presenting cells. The combination of this emulsion with the threonyl analog of MDP is termed Syntex Adjuvant Formulation. This formulation increases the efficacy of influenza, hepatitis B virus, herpes simplex virus, lentivirus and tumor vaccines in experimental animals.

Abstract  Recent work has established that secondary organic aerosol (SOA) can exist as an amorphous solid, leading to various suggestions that the addition of SOA coatings to existing particles will decrease the reactivity of those particles toward common atmospheric oxidants. Experimental evidence suggests that O3 is unable to physically diffuse through an exterior semisolid or solid layer thus inhibiting reaction with the core. The extent to which this suppression in reactivity occurs for OH has not been established, nor has this been demonstrated specifically for SOA. Here, measurements of the influence of adding a coating of α-pinene+O3 SOA onto squalane particles on the OH-initiated heterogeneous oxidation rate are reported. The chemical composition of the oxidized internally mixed particles was monitored online using a vacuum ultraviolet-aerosol mass spectrometer. Variations in the squalane oxidation rate with particle composition were quantified by measurement of the effective uptake coefficient, γeff, which is the loss rate of a species relative to the oxidant-particle collision rate. Instead of decreasing, the measured γeff increased continuously as the SOA coating thickness increased, by a factor of ∼2 for a SOA coating thickness of 42 nm (corresponding to ca. two-thirds of the particle mass). These results indicate that heterogeneous oxidation of ambient aerosol by OH radicals is not inhibited by SOA coatings, and further that condensed phase chemical pathways and rates in organic particles depend importantly on composition.

Abstract  As the test method of cosmetic ingredients safety evaluation, we performed open repeated patch test in rabbits. The members of this study were the researchers in three different cosmetic companies. The test materials were propylene glycol, 1, 3-butylene glycol, glycerine, pristane, liquid paraffin and squalane. We chose distilled water as negative control. We performed this test with the same procedure in each aboratory. The results were as following; (1) In polyols, the positive rate order was p ropylene glycol<1, 3-butylene glycol

Abstract  Insights into the influence of molecular structure and thermodynamic phase on the chemical mechanisms of hydroxyl radical-initiated heterogeneous oxidation are obtained by identifying reaction products of submicrometer particles composed of either n-octacosane (C28H58, a linear alkane) or squalane (C30H62, a highly branched alkane) and OH. A common pattern is observed in the positional isomers of octacosanone and octacosanol, with functionalization enhanced toward the end of the molecule. This suggests that relatively large linear alkanes are structured in submicrometer particles such that their ends are oriented toward the surface. For squalane, positional isomers of first-generation ketones and alcohols also form in distinct patterns. Ketones are favored on carbons adjacent to tertiary carbons, while hydroxyl groups are primarily found on tertiary carbons but also tend to form toward the end of the molecule. Some first-generation products, viz., hydroxycarbonyls and diols, contain two oxygen atoms. These results suggest that alkoxy radicals are important intermediates and undergo both intramolecular and intermolecular (chain propagation) hydrogen abstraction reactions. Oxidation products with carbon number less than the parent alkane's are observed to a much greater extent for squalane than for n-octacosane oxidation and can be explained by the preferential cleavage of bonds involving tertiary carbons.

Abstract  Measurements of the evolution of organic aerosol extinction cross sections (sigma(ext)) and subsaturated hygroscopicity upon heterogeneous OH oxidation are reported for two model compounds, squalane (a C-30 saturated hydrocarbon) and azelaic acid (a C-9 dicarboxylic acid). For both compounds, the sigma(ext) values at 532 nm increase substantially as the particles undergo oxidation, exhibiting a logarithmic increase with OH exposure. The increase in sigma(ext) correlates with both an increase in the particle oxygen to carbon (O:C) atomic ratio and density and a decrease in mean molecular weight. The measurements have been used to calculate the variation with oxidation of the mean polarizability, alpha, of the molecules comprising the particles. The absolute alpha values for the two systems are shown to be related through the variation in the particle chemical composition, specifically the relative abundances of C, O, and H atoms and the mean molecular weight. Unlike sigma(ext), it was found that the evolution of the particle hygroscopicity upon oxidation is quite different for the two model systems considered. Hygroscopicity was quantified by measuring gamma(ext), which is a single-parameter representation of hygroscopicity that describes the increase in extinction upon exposure of the particles to a high-relative humidity environment (here, 75% and 85% RH). For unoxidized squalane, gamma(ext) was zero and only increased slowly as the particles were oxidized by OH radicals. In contrast, gamma(ext) for azelaic acid increased rapidly upon exposure to OH, eventually reaching a plateau at high OH exposures. In general, gamma(ext) appears to vary sigmoidally with O:C, reaching a plateau at high O:C.

Abstract  The oxidative evolution ("aging") of organic species in the atmosphere is thought to have a major influence on the composition and properties of organic particulate matter but remains poorly understood, particularly for the most oxidized fraction of the aerosol. Here we measure the kinetics and products of the heterogeneous oxidation of highly oxidized organic aerosol, with an aim of better constraining such atmospheric aging processes. Submicrometer particles composed of model oxidized organics-1,2,3,4-butanetetracarboxylic acid (C8H10O8), citric acid (C6H8O7), tartaric acid (C4H6O6), and Suwannee River fulvic acid-were oxidized by gas-phase OH in a flow reactor, and the masses and elemental composition of the particles were monitored as a function of OH exposure. In contrast to our previous studies of less-oxidized model systems (squalane, erythritol, and levoglucosan), particle mass did not decrease significantly with heterogeneous oxidation. Carbon content of the aerosol always decreased somewhat, but this mass loss was approximately balanced by an increase in oxygen content. The estimated reactive uptake coefficients of the reactions range from 0.37 to 0.51 and indicate that such transformations occur at rates corresponding to 1-2 weeks in the atmosphere, suggesting their importance in the atmospheric lifecycle of organic particulate matter.

Abstract  The inelastic scattering of OH radicals from the surfaces of a sequence of potentially reactive organic liquids: squalane (C(30)H(62), 2,6,10,15,19,23-hexamethyltetracosane); squalene (C(30)H(50), trans-2,6,10,15,19,23-hexamethyltetracosa-2,6,10,14,18,22-hexaene); and oleic acid (C(18)H(34)O(2), cis-9-octadecanoic acid) was studied experimentally. A liquid long-chain perfluorinated polyether (PFPE, Krytox® 1506) was compared as a chemically inert reference. Gas-phase OH with an average laboratory-frame kinetic energy of 54 kJ mol(-1) was generated by 355-nm photolysis of a low-pressure of HONO a short distance (9 mm) above the liquid surface. Scattered OH was detected at the same distance by laser-induced fluorescence (LIF). Appearance profiles as a function of photolysis-probe delay were recorded for selected OH v' = 0, N' rotational levels. The efficiency of momentum transfer to the surface is least for PFPE and highest for squalane, with squalene and oleic acid intermediate, but in all cases the speed distributions are markedly too hot to be consistent with a thermal accommodation mechanism. The rotational distribution is found to be a function of scattered OH speed. The generally high rotational temperatures implied by the relative fluxes for N' = 1 and 5 were confirmed by LIF excitation spectra at the peak of the profile for each liquid. The trends in translational-to-rotational energy transfer were broadly consistent with the sequence in surface stiffness inferred from the translational inelasticity. The non-statistical distribution of OH fine-structure and Λ-doublet states produced by HONO photolysis appears to be effectively completely scrambled in collisions with the liquid surfaces. With due account taken of the product rotational distributions, and assuming that 100% of the OH scatters from PFPE, the integrated OH survival probabilities were: squalane (0.70 ± 0.08), squalene (0.61 ± 0.07) and oleic acid (0.76 ± 0.10). The 'missing' OH is presumed to have reacted at the liquid surface. Detailed comparison of the appearance profiles suggests that the main difference between squalane and squalene is loss of slower-moving OH, consistent with an additional capture mechanism at the vinyl sites.

Abstract  We investigated the reactive uptake of NO(3) (an important night-time oxidant in the atmosphere) on binary mixtures containing an unsaturated organic (methyl oleate) and saturated molecules (diethyl sebacate, dioctyl sebacate, and squalane) which we call matrix molecules. These studies were carried out to better understand the reactivity of unsaturated organics in multicomponent and multiphase atmospheric particles. For liquid binary mixtures the reactivity of methyl oleate depended on the matrix molecule. Assuming a bulk reaction, H(matrix)√(D(matrix)k(oleate)) varied by a factor of 2.7, and assuming a surface reaction H(matrix)(S)K(matrix)(S)k(oleate)(S) varied by a factor of 3.6, where H(matrix)√(D(matrix)k(oleate) and H(matrix)(S)K(matrix)(S)k(oleate)(S) are constants extracted from the data using the resistor model. For solid-liquid mixtures, the reactive uptake coefficient depended on exposure time: the uptake decreased by a factor of 10 after exposure to NO(3) for approximately 90 min. By assuming either a bulk or surface reaction, the atmospheric lifetime of methyl oleate in different matrices was estimated for moderately polluted atmospheric conditions. For all liquid mixtures, the lifetime was in the order of a few minutes (with an upper limit of 35 min). These lifetimes can be used as lower limits to the lifetimes in semi-solid mixtures. Our studies emphasize that the lifetime of unsaturated organics (similar to methyl oleate) is likely short if the particle matrix is in a liquid state.

Abstract  Faecal excretion of 2,4,5,2',4',5'-hexachlorobiphenyl (6-CB) was followed for 19 weeks in rats fed a control diet, or a squalane-supplemented diet, for up to 17 weeks. In 3 d after a single oral dose of 8 mg/kg of 6-CB, 20% dose was excreted in faeces as unchanged 6-CB, which probably represents that not-absorbed. From day 4 to 133 only an additional 2-4% dose was excreted in faeces by control animals. Addition of 8% squalane to the diet 2, 6 and 15 weeks after dosing resulted in a five-fold increase of daily 6-CB excretion in faeces independent of the time of beginning the treatment. Total excretion of 6-CB in faeces from day 4 to 133 was 3.6, 6-7 and 9.3% dose after 4, 13 and 17 weeks of squalane treatment, respectively. No adverse effects of long-term squalane treatment on body-weight gain, feed efficiency and organ weights were observed. Plasma cholesterol and triglycerides were significantly lowered. Independent of the duration of treatment, the livers of rats fed the squalane-supplemented diet contained 40-50 micrograms/g squalane. Within the limits of detection no squalane could be found in lungs, kidneys, abdominal fat, spleen and blood. It is concluded that 6-CB elimination can be enhanced by oral treatment with squalane even a long time after uptake of the poison. As there was no alteration in the tissue distribution of 6-CB, the 6-CB excreted after squalane treatment probably originates from all tissues.

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, the most important etiologic agent of Yusho, which was accumulated in the body of rat. We also reported that, in rats and dogs, squalane did not show any appreciable toxic signs during 3-month treatment, though a part of squalane was absorbed from gastrointestinal tract of dogs. In the present paper, we have investigated the elimination of absorbed squalane in beagle dogs. During the treatment with squalane orally at a dose of 1200 mg/kg/day for 14 days, the fecal excretion of squalane per day was 65-90% of the daily dose. After the treatment (on the day 14), squalane levels in blood and hair were about 30 ppm and 14640 ppm, respectively. On the day 56 after the first dosing, squalane was not detected in blood. On the day 70, squalane level in hair was reduced to about 1% of that on the day 14. Squalane levels in skin, liver, adipose tissue and small intestine on the day 70 were also reduced compared with that on the day 42. Moreover, small amount of squalane was still excreted into feces from the day 15 to the day 70. These results suggested that absorbed squalane was gradually excreted through feces and skin in dogs.

Abstract  We conducted the rabbit eye irritation test using the samples of three polyols (propylene glycol, 1, 3-butylene glycol and glycerin) as is and 10% in distilled water, and three hydrocarbons (liquid paraffin #72, squalane and pristane). Tests were performed in six labolatories, three with polyols and three with hydrocarbons. Comparing the reactions of three laboratories, propylene glycol and glycerin as is showed the same irritancy and 1, 3-butylene glycol showed a little lower irritancy than formers. 10% polyols and hydrocarbons showed low irritancy and no differences between the three chemicals were observed. By the way, no clear reduction effects of irritation by washing the eyes were seen. Though differences were shown in the grade of reactions between three laboratories, there was shown the same order as to the irritation grade of three chemicals.

Abstract  Multiphase chemical reactions (gas + solid/liquid) involve a complex interplay between bulk and interface chemistry, diffusion, evaporation, and condensation. Reactions of atmospheric aerosols are an important example of this type of chemistry: the rich array of particle phase states and multiphase transformation pathways produce diverse but poorly understood interactions between chemistry and transport. Their chemistry is of intrinsic interest because of their role in controlling climate. Their characteristics also make them useful models for the study of principles of reactivity of condensed materials under confined conditions. In previous work, we have reported a computational study of the oxidation chemistry of a liquid aliphatic aerosol. In this study, we extend the calculations to investigate nearly the same reactions at a semisolid gas-aerosol interface. A reaction-diffusion model for heterogeneous oxidation of triacontane by hydroxyl radicals (OH) is described, and its predictions are compared to measurements of aerosol size and composition, which evolve continuously during oxidation. These results are also explicitly compared to those obtained for the corresponding liquid system, squalane, to pinpoint salient elements controlling reactivity. The diffusive confinement of the free radical intermediates at the interface results in enhanced importance of a few specific chemical processes such as the involvement of aldehydes in fragmentation and evaporation, and a significant role of radical-radical reactions in product formation. The simulations show that under typical laboratory conditions semisolid aerosols have highly oxidized nanometer-scale interfaces that encapsulate an unreacted core and may confer distinct optical properties and enhanced hygroscopicity. This highly oxidized layer dynamically evolves with reaction, which we propose to result in plasticization. The validated model is used to predict chemistry under atmospheric conditions, where the OH radical concentration is much lower. The oxidation reactions are more strongly influenced by diffusion in the particle, resulting in a more liquid-like character.