Abstract  π-A isotherms, atomic force microscopy (AFM), and sum frequency generation (SFG) vibrational spectroscopy are employed to investigate the molecular structure and lateral interactions in mixed monolayers of dioctadecyldimethylammonium chloride (DOAC) and stearyl alcohol (SA) at air/water and air/solid interfaces. To avoid possible interference between the two molecules in the SFG spectroscopic measurements, perprotonated DOAC and perdeuterated SA (dSA) were used. The thermodynamic analyses for the π-A isotherms show that DOAC is miscible with dSA. SFG observations reveal that DOAC molecules become conformationally ordered as dSA molecules are introduced into the monolayer. AFM observations demonstrate coexistence of DOAC-rich and dSA-rich domains in the mixed monolayer with ratios different from their initial composition in the subphase. The present study suggests that DOAC molecules in the mixed monolayer are condensed by mixing with dSA in which the repulsive interactions between positively charged head groups of the DOAC molecules are largely reduced along with an increase of van der Waals interactions with dSA.

Abstract  To reveal the effects of particle size distributions on flame propagation mechanism during octadecanol dust explosions clearly, the flame propagation through dust clouds with three different particle size distributions in an open space were recorded using an approach combined by high-speed photography and band-pass filter. From the direct light emission photographs and CH emission photographs, it has been demonstrated in the experiments that the flame front structures were changed as varying the particle size distributions. Flame propagated in the dust cloud with a smaller particle size was characterized by a regular shape and spatially continuous combustion zone structure, which was similar to the premixed gas explosions. On the contrary, when flame propagated through the dust cloud with a larger particle size, discrete blue luminous spots appeared surrounding the yellow luminous zone. Further increase in diameter resulted mostly in the appearance of blue spot flames and the disappearance of yellow luminous zone in the flame propagation process. Additionally, a simple mathematical model was developed to determine the critical particle size to illustrate the different flame propagation mechanisms in octadecanol dust explosions. (C) 2013 Elsevier B.V. All rights reserved.

Abstract  Submicron aerosol particles were collected during July and August 2010 in Hyytiala, Finland, to determine the composition and sources of aerosol at that boreal forest site. Submicron particles were collected on Teflon filters and analyzed by Fourier transform infrared (FTIR) spectroscopy for organic functional groups (OFGs). Positive matrix factorization (PMF) was applied to aerosol mass spectrometry (AMS) measurements and FTIR spectra to identify summertime sources of submicron aerosol mass at the sampling site. The two largest sources of organic mass (OM) in particles identified at Hyytiala were (1) biogenic aerosol from surrounding local forest and (2) biomass burning aerosol, transported 4-5 days from large wildfires burning near Moscow, Russia, and northern Ukraine. The robustness of this apportionment is supported by the agreement of two independent analytical methods for organic measurements with three statistical techniques. FTIR factor analysis was more sensitive to the chemical differences between biogenic and biomass burning organic components, while AMS factor analysis had a higher time resolution that more clearly linked the temporal behavior of separate OM factors to that of different source tracers even though their fragment mass spectrum were similar. The greater chemical sensitivity of the FTIR is attributed to the nondestructive preparation and the functional group specificity of spectroscopy. The FTIR spectra show strong similarities among biogenic and biomass burning factors from different regions as well as with reference OM (namely olive tree burning organic aerosol and alpha-pinene chamber secondary organic aerosol (SOA)). The biogenic factor correlated strongly with temperature and oxidation products of biogenic volatile organic compounds (BVOCs), included more than half of the oxygenated OFGs (carbonyl groups at 29% and carboxylic acid groups at 22 %), and represented 35% of the submicron OM. Compared to previous studies at Hyytiala, the summertime biogenic OM is 1.5 to 3 times larger than springtime biogenic OM (0.64 mu g m(-3) and 0.4 mu g m(-3), measured in 2005 and 2007, respectively), even though it contributed only 35% of OM. The biomass burning factor contributed 25% of OM on average and up to 62% of OM during three periods of transported biomass burning emissions: 26-28 July, 29-30 July, and 8-9 August, with OFG consisting mostly of carbonyl (41 %) and alcohol (25 %) groups. The high summertime terrestrial biogenic OM (1.7 mu g m(-3)) and the high biomass burning contributions (1.2 mu g m(-3)) were likely due to the abnormally high temperatures that resulted in both stressed boreal forest conditions with high regional BVOC emissions and numerous wildfires in upwind regions.

Abstract  A valid assessment of selective aerobic degradation on organic matter (OM) and its impact on OM-based proxies is vital to produce accurate environmental reconstructions. However, most studies investigating these effects suffer from inherent environmental heterogeneities. In this study, we used surface samples collected along two meter-scale transects and one longer transect in the northeastern Arabian Sea to constrain initial OM heterogeneity, in order to evaluate selective aerobic degradation on temperature, productivity and alteration indices at the sediment-water interface. All of the studied alteration indices, the higher plant alkane index, alcohol preservation index, and diol oxidation index, demonstrated that they are sensitive indicators for changes in the oxygen regime. Several export production indices, a cholesterol-based stanol/stenol index and dinoflagellate lipid- and cyst-based ratios, showed significant (more than 20%) change only over the lateral oxygen gradients. Therefore, these compounds do not exclusively reflect surface water productivity, but are significantly altered after deposition. Two of the proxies, glycerol dibiphytanyl glycerol tetraether-based TEX86 sea surface temperature indices and indices based on phytol, phytane and pristane, did not show any trends related to oxygen. Nevertheless, unrealistic sea surface temperatures were obtained after application of the TEX86, TEX86L, and TEX86H proxies. The phytol-based ratios were likely affected by the sedimentary production of pristane. Our results demonstrate the selective impact of aerobic organic matter degradation on the lipid and palynomorph composition of surface sediments along a short lateral oxygen gradient and suggest that some of the investigated proxies may be useful tracers of changing redox conditions at the sediment-water interface.

Abstract  Eight phthalate esters, with alcohol chain lengths of 1-11 carbon atoms and with various degrees of branching, were tested in vitro in the L5178Y mouse lymphoma mammalian cell mutation assay and in the Balb/3T3 cell transformation assay. The tests were performed as part of a voluntary testing agreement between the Chemical Manufacturers Association's Phthalate Esters Panel and the United States Environmental Protection Agency (US EPA). The esters tested were: dimethyl phthalate (DMP), di-n-butyl phthalate (DBP), butyl benzyl phthalate (BBP), di- inverted question markn-hexyl, n-octyl, n-decyl inverted question mark phthalate (610P), di-isononyl phthalate (DINP), di- inverted question markheptyl, nonyl, undecyl inverted question mark phthalate (711P), di-isodecyl phthalate (DIDP) and di-undecyl phthalate (DUP). Both DMP and DBP were found to produce significant increases in the mutant frequency in the mouse lymphoma assay in the presence but not in the absence of an Aroclor-induced rat liver activation system (S-9). Ester 610P gave equivocal results in the mouse lymphoma assay in the presence and absence of rat liver S-9. There was no indication of mutagenic potential for any of the other test materials in the mouse lymphoma assay, and none of the test materials increased transformation frequency in the Balb/3T3 cell transformation assay. Aldehyde metabolites of the de-esterified alcohols are postulated to play a role in the positive results for DMP and DBP.

Abstract  49 substances permitted for use in food in the United States was tested for mutagenicity in the Ames Salmonella typhimurium assay and in Escherichia coli strain WP2. Four of these substances caused increases in revertant counts in S. typhimurium. Two of these four (papain and pepsin) were found to contain histidine, and therefore the results of the tests on these two substances could not be taken as demonstrating mutagenicity. The other two substances causing increases in revertant counts (hydrogen peroxide and potassium nitrite) were mutagenic. The results on one chemical, beta-carotene, were evaluated as inconclusive or questionable. The remaining 44 substances were nonmutagenic in the test systems used. It is concluded that, for those generally physiologically innocuous chemicals tested, there are very few 'false positives' in the bacterial test systems used.

Abstract  In order to obtain a novel prescription to treat scald, a new ointment was assessed. The ointment was made of pepsin soluble collagen (PSC), Bletilla striata polysaccharide (CBSP), lentinan, 1-octadecanol, dodecyl sodium sulfate, white vaseline, methyl hydroxybenzoate, propyl hydroxybenzoate, propylene glycol and distilled water. Experiment involving mice with their biochemical assays was used to evaluate the suitability of the ointment. The ointment which include by 1.5 g PSC, 1.5 g CBSP, 1.5 g lentinan, 20 g 1-octadecanol, 1.46 g dodecyl sodium sulfate, 23 g white vaseline, 0.025 g methyl hydroxybenzoate, 0.015 g propyl hydroxybenzoate, 11 g propylene glycol, and 40 g distilled water is optimal ointment. The scar outcomes rate all reach 100.00% in ointment group and model group. However, the ointment group of scar outcomes rate is higher than model group in the tenth day. The ointment 1, 2 and 3 group can significantly improve the activity of superoxide dismutase, increase the content of monoamine oxidase and reduce the content of malondialdehyde. The ointment had no influence on the body mass, the relative organ mass, blood hematology and serum biochemical indices of the mice. The results of the study indicated that the ointment can be used to treat scalds on mouse, increase the rate of the scar outcome and promote scald heal.

Abstract  Aerobic oxidation of a thin film of octadecanol at 105 degrees C and ambient pressures to its corresponding carbonyl derivatives (a mixture of aldehyde and carboxylic acid) was for the first time performed over a flat-model (i.e. two-dimensional), silicon wafer-supported metallic silver catalyst. The experimental set-up was extraordinary simple. An open-to-the-atmosphere glass beaker was used as reactor. Just enough octadecanol was placed on the silicon-supported catalytic surface to cover it with a thin film when melted. Reaction progress was monitored by ATR-FTIR analyses to identify the appearance of octadecanal and octadecanoic acid carbonyl stretching peaks at 1730 and 1710 cm(-1) respectively. The successful demonstration of this simple approach in studying catalysed small-molecule condensed organic reactions opens a new avenue towards simplified catalytic mechanistic studies of such processes. The catalyst was prepared by spin coating silver nitrate on a flat silicon wafer with (100) surface orientation, pretreated to have 4-5 silanol (-Si-OH) groups per nm(2). Reduction by hydrogen at 350 degrees C afforded metallic silver particles on the two-dimensional support at a nominal surface concentration of ca. 21-23 silver atoms/nm(2). XPS differentiation between the catalyst precursor, AgNO3. and the metallic silver catalytic surface required use of the Auger MNN kinetic energies. TEM studies of the active catalyst showed no serious aggregation of metallic Ag particles occurred during reduction. (C) 2012 Elsevier B.V. All rights reserved.

Abstract  Purpose: To ascertain the influence of paraffin, white soft paraffin and pre-hydrated white soft paraffin on the viscosity of a cream formulated with a corticosteroid. Methods: The formulations were prepared via homogenization with variable velocity in the range 3300 4000 rpm. Individual series of preparations contained the same proportion of macrogol cetostearyl alcohol, cetyl alcohol, stearyl alcohol, sorbitan stearate, propylene glycol, metyl parahydroxybenzoate, propyl parahydroxybenzoate and water. The semi-solid preparations were assessed by viscometric and microscopic methods. Results: The viscosity of the samples measured ranged from 13050 to 15660 mPas. The particles in dispersed phase sized from 15 to 90 mu m. Within the multiple emulsion, the continuous phase included fine particles with diameter < 5 mu m. Change of the liquid paraffin used from Ondina 934 to Vara 600P significantly decreased the viscosity of the formulation. Several phases within the formulations were distinguished microscopically. Increased viscosity was observed in formulations with increasing proportion of white soft paraffin. Conclusion: Both the ratio of liquid paraffin to white soft paraffin, as well as the initial hydration of white soft paraffin influenced the viscosity of the cream as well as the diameter of particles in the dispersed phase.

Abstract  The intact preen wax esters of the red knot Calidris canutus were studied with gas chromatography/mass spectrometry (GC/MS) and GC/MS/MS. In this latter technique, transitions from the molecular ion to fragment ions representing the fatty acid moiety of the wax esters were measured, providing additional resolution to the analysis of wax esters. The C21-C32 wax esters are composed of complex mixtures of hundreds of individual isomers. The odd carbon-numbered wax esters are predominantly composed of even carbon-numbered n-alcohols (C14, C16, and C18) esterified predominantly with odd carbon-numbered 2-methyl fatty acids (C7, C9, C11, and C13), resulting in relatively simple distributions. The even carbon-numbered wax esters show a far more complex distribution due to a number of factors: (i) Their n-alcohol moieties are not dominated by even carbon-numbered n-alcohols esterified with odd carbon-numbered 2-methyl fatty acids, but odd and even carbon-numbered n-alcohols participate in approximately equal amounts; (ii) odd carbon-numbered methyl-branched alcohols participate abundantly in these wax ester clusters; and (iii) with increasing molecular weight, various isomers of the 2,6-, 2,8-, and 2,10-dimethyl branched fatty acids also participate in the even carbon-numbered wax esters. The data demonstrate that there is a clear biosynthetic control on the wax ester composition although the reasons for the complex chemistry of the waxes are not yet understood.

Abstract  The nematode Caenorhabditis elegans arrests development at the first larval stage if food is not present upon hatching. Larvae in this stage provide an excellent model for studying stress responses during development. We found that supplementing starved larvae with ethanol markedly extends their lifespan within this L1 diapause. The effects of ethanol-induced lifespan extension can be observed when the ethanol is added to the medium at any time between 0 and 10 days after hatching. The lowest ethanol concentration that extended lifespan was 1 mM (0.005%); higher concentrations to 68 mM (0.4%) did not result in increased survival. In spite of their extended survival, larvae did not progress to the L2 stage. Supplementing starved cultures with n-propanol and n-butanol also extended lifespan, but methanol and isopropanol had no measurable effect. Mass spectrometry analysis of nematode fatty acids and amino acids revealed that L1 larvae can incorporate atoms from ethanol into both types of molecules. Based on these data, we suggest that ethanol supplementation may extend the lifespan of L1 larvae by either serving as a carbon and energy source and/or by inducing a stress response.

Abstract  BIOSIS COPYRIGHT: BIOL ABS. The application of Salmonella/microsomal mammalian tests to column chromatography fractions isolated from river and marine sediments collected in the vicinity of Barcelona City, Spain, demonstrated a positive response (TA98+S9 mix) among the polar fractions. Chemical analysis by high resolution gas chromatography coupled to negative ion chemical ionization mass spectrometry (HRGC-NICI MS) provided sensitivity and selectivity to detect several mutagenic chemical classes. Among them, nitrated PAHs, azaarenes, aromatic amines, anhydrides, and ketones were identified. A total of 116 compounds were tentatively identified, 22 for the first time, of which 16 possessed mutagenic activity. However, a lack of correlation between chemical composition and fraction mutagenicity in the medium polarity fractions, especially in the river sediment, was evidenced. The occurrence of multiple interactions between components in spiked organic extracts is demonstrated.

Abstract  Structure-activity relationships between acute toxicities of 95 alcohols to rat and mouse (oral LD50) and four special substructure factors, hydroxyl number, carbon atom number were examined by means of expert system method. The results showed that the expert system based QSAR model was excellent for classification for miscellaneous alcohols (only 9 of them were wrong classified). It was also used to predict the toxicity of other 25 alcohols, and the false prediction rate was only 12%.

Abstract  A laboratory investigation on the biotransformation of 8:2 fluorotelomer stearate monoester (8:2 FTS) in aerobic soils was conducted by monitoring the loss of 8:2 FTS, production of 8:2 fluorotelomer alcohol (8:2 FTOH) and stearic acid, which would be released by cleavage of the ester linkage, and subsequent degradation products from FTOH for 80 d. Soil microcosms were extracted with ethyl acetate followed by two heated 90/10 v/v acetonitrile/200 mM NaOH extractions. 8:2 FTS was degraded with an observed half-life (t(1/2)) of 10.3 d. The rate of 8:2 FTS biotransformation substantially decreased after 20 d with 22% of 8:2 FTS still remaining on day 80. No biotransformation of 8:2 FTS occurred in autoclaved soil controls, which remained sterile with 102 ± 6% recovery, through day 20. 8:2 FTOH was generated with cleavage of the ester linkage of 8:2 FTS followed by a rapid decline (t(1/2) ~ 2 d) due to subsequent biodegradation. All the expected 8:2 FTOH degradation products were detected including 8:2 fluorotelomer unsaturated and saturated carboxylic acids, 7:2s FTOH, 7:3 acid, and three perfluoroalkyl carboxylic acids with the most prominent being perfluorooctanoic acid (PFOA). PFOA consistently increased over time reaching 1.7 ± 0.07 mol % by day 80. Although cleavage of the ester linkage was evidenced by 8:2 FTOH production, an associated trend in stearic acid concentrations was not clear because of complex fatty acid metabolism dynamics in soil. Further analysis of mass spectrometry fragmentation patterns and chromatography supported the conclusion that hydrolysis of the ester linkage is predominantly the first step in the degradation of 8:2 FTS with the ultimate formation of terminal products such as PFOA.

Abstract  In the present work some stability studies on Supported Liquid Membranes (SLMs) to be used for chiral separations were realized. In particular, primary aim was to determine how a modification of the support surface influences the SLM stability. First, the procedure for support modification was optimised, making a screening of various compounds (sulphuric acid, nitric acid, chromic acid, sodium dodecyl sulphate (SDS), glycerol, oleic alcohol, propylene glycol (PPG), bovine serum albumin (BSA)) and testing their performance by means of contact angle measurements. Next, a second screening was realized by permeation tests in a stirred cell. Finally, to compare the stability of modified with unmodified support in a process of interest for chemical and/or biochemical industries, some permeation tests for resolution of DNB-DL-Leucine were realized in a re-circulation system. Results showed a better surface hydrophilization of chemically modified support and better stability of the sulphonated support. However, in operating conditions a little high stability of the unmodified support was obtained.

Abstract  Systematically synthetic zinc 3-hydroxymethyl-131-oxo-chlorins esterified by different linear alcohols (methanol, 1-propanol, 1-hexanol, 1-dodecanol and 1-octadecanol) at the 17-propionate were self-assembled in the presence of cetyltrimethylammonium bromide in an aqueous solution. These zinc chlorins exhibited red-shifted Qy absorption bands and circular dichroism (CD) signals in the corresponding Qy region after incubation for 17h, indicating that the zinc chlorins formed self-aggregates like those in natural chlorosomes of green photosynthetic bacteria. Visible absorption and CD spectra of self-aggregates of the zinc chlorins depended on the length of their esterifying alcohols. Zinc chlorins esterified by shorter alcohols gave larger changes in their visible absorption and CD spectra after incubation above 40 degrees C, whereas zinc chlorins esterified by longer alcohols afforded smaller changes. These results indicate that hydrophobic interaction among esterifying chains of chlorin molecules as well as that between the esterifying chains and peripheral surfactants or lipids play an important role in the stability of chlorosomal self-aggregates.

Abstract  Breflate is a water soluble prodrug developed to facilitate parenteral administration of the investigational antineoplastic agent brefeldin A (BFA). Previously, using analytical methods based upon reversed-phase high performance liquid chromatography (HPLC) with low wavelength UV detection or gas chromatography (GC) with electron capture detection following derivatization with heptafluorobutyrylimidazole, it was demonstrated that breflate undergoes rapid and efficient conversion to BFA following bolus i.v. injection in mice and dogs. However, plasma concentrations of the drug and prodrug achieved during the administration of nontoxic doses of breflate to beagle dogs as a 72 h continuous i.v. infusion were undetectable (< 0.1 microgram ml-1) by these methods. The sensitivity and specificity required for therapeutic drug level monitoring were achieved by GC with selected-ion mass spectrometry (MS) detection. Breflate, BFA and 1-eicosanol, the latter added to the sample as an internal standard (IS), were extracted from plasma into tert-butyl methyl ether (TBME) and esterified with trifluoroacetic anhydride. Methanol was added to the reaction mixture to effect the convenient removal of excess reagent as the volatile methyl ester during evaporation of the solvent. The residual material was analyzed directly upon reconstitution by capillary GC with automated splitless injection. Electron-ionization (70 eV) MS detection was performed by sequentially scanning ions at m/z 58, 202 and 325. The lowest concentration of either analyte quantified with acceptable reproducibility, as defined by an inter-day R.S.D. of about 20%, was near 10 ng ml-1 in plasma using a sample volume of 100 microliters. The assay has proven to be sufficiently sensitive, specific and reproducible for the routine analysis of pharmacokinetic specimens acquired during IND (investigational new drug)-directed toxicology studies in dogs.

Abstract  Scanning tunneling microscopy (STM) images of 1-docosanol, 1-docosanethiol, didocosyl disulfide, and 1-chlorooctadecane on graphite are compared. The images of the 1-docosanethiol and didocosyl disulfide show bright spots which are attributed to the positions of the S-H and S-S functional groups. The STM images of the 1-docosanol and 1- chlorooctadecane do not show such bright spots. The fact that both the S-H and S-S groups appear bright in the STM images indicates that the presence of an S atom on graphite results in a higher tunneling current when the tip scans over it compared to the tunneling current over a C, O, or Cl atom. The different behavior of the S atoms compared to the O, C, and Cl atoms is discussed in terms of the interactions between these atoms and the underlying graphite substrate. The persistent brightness of S atoms in the images of molecular adsorbates suggests that sulfur may serve as a useful ''chromophore'' for molecules imaged by STM.

Abstract  A new derivatization procedure to increase the sensitivity of electrospray ionization mass spectrometry (ESI-MS) to non-ethoxylated and ethoxylated alcohols was investigated. The analytes were oxidized with chromium(VI) oxide and the resulting carboxylic and ethoxy-carboxylic acids were isolated by extraction with ethyl acetate; the extracts were alkalinized and infused into the ESI-MS system working in the negative-ion mode. The yields of the combined oxidation-extraction were ca. 100% for non-ethoxylated fatty alcohols dissolved in acetone and they decreased moderately in samples containing increasing amounts of water (e.g., a 75% yield was obtained with 50% water). Ethoxylated alcohols with more than two ethylene oxide units resulted in yields of ca. 60%. Low limits of detection (LODs) were obtained when the procedure was applied to the analysis of body-care products and cosmetics containing fatty alcohols, e.g., in a varicose-vein cream, the LODs were 25 microg cetyl alcohol and 7.5 microg stearyl alcohol (detected as palmitic acid and stearic acid, respectively) per gram of sample. High molecular mass alcohols were also detected in seawater after pre-concentration by solid-phase extraction. Thus, the proposed method is particularly valuable for use in industrial samples having complex matrices and in environmental samples and it is competitive with other methods for the analysis of trace amounts of fatty alcohols.

Abstract  Continuous butanol/isopropanol fermentation with immobilized Clostridium isopropylicum was performed in a downflow column reactor using molasses as the substrate. In order to prevent product inhibition and at the same time obtain high concentration of the products, the column reactor was coupled with a pervaporation module using a supported liquid membrane. The liquid membrane was prepared with oleyl alcohol nontoxic to the microorganism. In comparison with the continuous fermentation without product removal, the specific butanol production rate was 2 times higher. The butanol concentration in the permeate was 230 kg/m(3), which was about 50 times higher than that in the culture broth. A numerical investigation suggested a further increase in the productivity by improving the module construction.

Abstract  The rabbit external ear canal was used to define which chemicals caused comedone formation on topical application. Some of the tested ingredients are currently used in topically applied formulations. Certain raw materials have been shown to produce follicular hyperkeratosis in the rabbit ear assay. This study quantifies comedogenic potential of cosmetic materials, including: isopropyl palmitate, isopropyl myristate, butyl stearate, isopropyl isostearate, decyl oleate, isostearyl neopentanoate, isocetyl stearate, myristle myristate, cocoa butter, cetyl alcohol, paraffin, stearyl alcohol sodium lauryl sulfate (SLS), and petrolatum. The first nine were deemed positive. Factors aiding clinical relevance are listed.

Abstract  Emulsion copolymerization of vinyl chloride with vinyl acetate comonomer was performed. Potassium persulfate, a mixture of stearyl alcohol and sodium lauryl sulfate, was used and reactions were performed at 55 degrees C in a pressurized reactor. By sampling during the reaction in different intervals copolymer composition was investigated using FTIR and NMR spectroscopy. The results showed that the partitioning of vinyl acetate in the copolymerization in general follows the Mayo-Lewis copolymerization equation with some discrepancy. This was attributed to the gaseous nature of vinyl chloride monomer and the differences between polymerization in heterogeneous and homogeneous systems. Both FT - IR and NMR spectroscopy showed two peaks in vinyl acetate content of copolymer beyond 65% conversion which was attributed to the elimination of vinyl chloride droplets in the media and replacing them with vinyl acetate monomer. The first increase is related to the consumption of vinyl chloride droplets and the second is related to the consumption of gaseous vinyl chloride; in both instances vinyl acetate governs the polymerization.

Abstract  Experiments concerning the effect of shear flow on the turbidity of a colloidal dispersion close to its gas-liquid critical point are described. Theory predicts that in the mean-field region, the turbidity of the sheared syst em relative to that of the quiescent dispersion is a function of a single dimensionless group lambda that is proportional to gamma xi(-4) (gamma is the shear rate and xi(-1) is the correlation length of the quiescent dispersion at the given temperature). Experiments are found to be in accordance with this scaling behavior. Moreover, the experiments confirm the theoretically predicted lambda dependence. As a model colloidal system, we used spherical silica particles coated with stearyl alcohol. When dissolved in benzene, these colloidal particles attract each other, due to the fact that benzene is a marginal solvent for the stearyl coating. These attractions give rise to a gas-liquid critical point.

Abstract  HEEP COPYRIGHT: BIOL ABS. Two O2-containing derivatives of unsaturated fatty acids, methyl 12-oxo-trans- 10-octade-cenoate and methyl hydroxyoctadecadienoate, both highly active in the newt test for carcinogenicity, were tested as complete carcinogens and as promoting agents by application to the skin of ST/a mice. Through observation for 2 yr the tumorigenic effect was recorded and compared with that of methyl oleate and adequate positive control substances: 7,12-dimethylbenz(alpha)anthracene and croton oil. Methyl oxoctadecenoate and hydroxyoctadecadienoate showed a significant potency to promote the induction of skin papillomas. The genesis of malignant skin tumors was promoted by methyl oleate and oxoctadecnoate and all 3 methyl esters had weak activity as complete carcinogens to the skin. As a systemic effect all esters promoted the induction of malignant lymphomas, most markedly methyl oxoctadecenoate. Even without preceding initiation this ester and methyl oleate had some activity in lymphoma induction. The various observations show that, when tested by these procedures, methyl oxoctadecenoate is the ester most active in the induction of tumors and the effect is essentially that of a promoter. The relation between molecular configuration and carcinogenicity of fatty acids is discussed.

Abstract  Rosewood tree has high adaptability to environment and tolerance to water stress, and a long history of utilization and plantation in many countries. However, researches on Rosewood were mostly focused on the biomass analyses and utilizations of its wood, and lacked those to analyze the chemical components of extractives of Rosewood leaves, which was very important to recover and utilize the polluting waste Rosewood leaves. Therefore, the chemical components of benzene/ethanol extractives of Rosewood leaves were analyzed by method of GC/MS in order to identify top value-added bioactive components from waste leaves of Rosewood tree. The analytical result showed that the main components of benzene/ethanol extractives of freeze-dried Rosewood leaves by GC/MS analysis were identified 16 constituent (16 peaks) as: Ethanol, 2-butoxy- (40.36%), 2-O-Methyl-D-mannopyranosa (18.22 %), Hydrazine, 1,1-dipropyl- (6.09%), 1-Docosanol (5.59%), 1-Eicosanol (5.28%), Oxirane, hexadecyl- (3.63%), trans-2,4,5-Trimethoxy-center dot beta center dot-methyl- (3.50%), Bicyclo[3.1.1]heptane, 2,6,6-trimethyl- (2.53%), 9,12,15-Octadecatrienoic acid, methyl- (2.43%), Tetratetracontane (2.31%), Hexadecane, 1-(ethenyloxy)- (2.27%), Cholan-24-oic acid, 7,12-bis(acetyloxy)-3-ethoxy-, methyl ester, (3.alpha.,5.beta.)- (2.10%), Hexatriacontane (2.02%), Phytol (1.76%), Octadecane, 1-chloro (1.08%), etc. As the first report here, our result by GC/MS showed that the benzene-methanol extractive of freeze-dried Rosewood leaves can be developed into top value-added materials of medicines, biofuel, and industrial solvents.