Showing papers on "Liquid paraffin published in 1998"

Study of lactic acid extraction with higher molecular weight aliphatic amines

Abstract: Lactic acid extraction was studied with two extractants, trioctyl amine (TOA) and Aliquat 336, in three diluents (methylisobutyl ketone (MIBK), octanol and paraffin liquid). The effects of organic phase extractant concentration and aqueous phase pH on the extraction process were examined. Among the extractants, TOA was found to be a better extractant than Aliquat 336 in all the diluents. In experiments with 50% (v/v) TOA in methylisobutyl ketone, 79% lactic acid could be extracted (initial lactic acid concentration 86·96 g dm−3). MIBK had a profound effect on the extraction behaviour of TOA in comparison with octanol and paraffin liquid while none of the diluents affected the extraction with Aliquat 336. The extraction of lactic acid was favoured at low pH. The toxicities of TOA and the diluents to Lactobacillus rhamnosus NRRL B445 were also studied. While TOA was found to be highly toxic at the molecular and the phase level, the paraffin liquid was totally non-toxic. The extraction of glucose and yeast extract by TOA and the diluents used was found to be low, which thus enables the selective extraction of lactic acid. © 1998 SCI

Friction and wear characteristics of fiber‐ and whisker‐reinforced PTFE composites under oil lubricated conditions

Abstract: Four kinds of polytetrafluoroethylene (PTFE)-based composites, such as pure PTFE, PTFE + 30(vol.)% carbon fiber, PTFE + 30(vol.)% glass fiber, and PTFE + 30(vol.)% K2Ti6O13 whisker composite, were prepared. The friction and wear properties of these fiber- and whisker-reinforced PTFE composites sliding against GCr15-bearing steel (SAE52100 steel) under both dry and liquid paraffin lubricated conditions were studied by using an MHK-500 ring-block wear tester (Timken wear tester). Then the worn surfaces of these PTFE composites and the transfer films formed on the surface of GCr15-bearing steel were investigated by using a Scanning Electron Microscope (SEM) and an Optical Microscope, respectively. Experimental results show that the friction and wear properties of the PTFE composites reinforced with carbon fiber, glass fiber, and a K2Ti6O13 whisker can be greatly improved by lubrication with liquid paraffin, and the friction coefficients of these PTFE composites can be decreased by one order of magnitude compared to those under dry friction conditions. Meanwhile, the wear of the fiber- and whisker-reinforced PTFE composites in liquid paraffin lubrication increases with the increase of load, but the friction coefficients of these PTFE composites first decrease with the increase of load, and then increase with the increase of load. The variations of friction coefficients with load for these PTFE composites in liquid paraffin lubrication can be described properly by the Stribeck's curve as given in this article. However, when the load increases to the load limits of the PTFE composites, their friction and wear increase sharply. SEM and optical microscope investigations show that the interactions between liquid paraffin and the PTFE composites, especially the absorption of liquid paraffin into the surface layers of the PTFE composites, create some obvious cracks on the worn surfaces of the PTFE composites. The creation and the development of the cracks reduce the load-carrying capacity of the PTFE composites, and therefore lead to the increase of the friction and wear of the PTFE composites under higher loads. Meanwhile, the transfer of the fiber- and whisker-reinforced PTFE composites onto the counterfaces can be greatly reduced by lubrication with liquid paraffin, but the transfer still takes place. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 69: 1393–1402, 1998

Effect of HD-03, a herbal formulation, on the antioxidant defence system in rats

Abstract: The effect of HD-03, a herbal formulation was investigated on the hepatocellular antioxidant defence system in CCl4 treated rats. Three doses of CCl4 were administered orally with liquid paraffin (1:1) to induce hepatic damage. Twenty four hours after the last dose, blood was collected by decapitation for the estimation of serum ALT and AST. The levels of antioxidant enzymes, lipid peroxidation and glycogen in the liver were estimated. Nineteen days pretreatment with HD-03 (750 mg/kg) significantly reversed CCl4-induced changes in serum ALT and AST levels. HD-03 pretreatment also significantly reversed the CCl4-induced changes in the different components of the cellular antioxidant system and lipid peroxidation. Pretreatment with HD-03 significantly restored the hepatic glycogen levels which were depleted in CCl4 intoxicated rats. The observed reversal produced by HD-03 in the serum AST and ALT may be due to the membrane stabilizing potential which helps in preventing the leakage of intracellular enzymes into the systemic circulation. The increase in the hepatic glycogen levels in HD-03 pretreated rats, indicates its preventive effect on subcellular injury caused by CCl4, which leads to glycogenolysis, as a result of disturbance in the intracellular Ca+2 pool. The inhibition of lipid peroxidation and enhancement in the activity of antioxidant enzymes by HD-03 may be due to the direct free radical scavenging activity and reactivation of these enzymes in the liver. Thus the antioxidant potential and inhibitory effect on­lipid peroxidation may play an important role in the antihepatotoxic activity of HD-03. © 1998 John Wiley & Sons, Ltd.

Antibody responses of rats after immunization with organic acid anhydrides as a model of predictive testing

Abstract: OBJECTIVES: The sensitizing properties of organic acid anhydrides (OAA) were evaluated in a rat model. METHODS: The development of specific immunoglobulin (Ig)E and Ig G in serum was investigated after immunization with 14 OAA and 3 OAA conjugates. Brown Norway rats were injected intradermally with 0.1 ml of 0.2 M OAA in liquid paraffin or 1.4 mg of rat serum albumin conjugate in saline. Serum samples were collected after 4 weeks. Antibodies were analyzed with enzyme-linked immunosorbent assay. RESULTS: The serum titers of specific Ig E after immunization with the different free OAA varied from <50 to 6400. The rats immunized with 4-methylphthalic anhydride exhibited the highest titers. The specificity of Ig E was demonstrated by enzyme-linked immunosorbent assay inhibition tests. A good correlation was observed between the Ig E and Ig G titers. Immunization with OAA conjugates showed results parallel to the findings for the free compounds. Importantly, the Ig E titers for the OAA agreed well with findings from guinea pigs and with literature data from epidemiologic studies of exposed workers. CONCLUSIONS: The present animal model may be a valuable tool for predicting the sensitizing potential of OAA and possibly the sensitizing potential of low-molecular-weight compounds in general. Furthermore, the antibody specificity of the haptens and the variations in the magnitude of the antibody titers indicate a valuable approach for studies of quantitative structure-activity relationships. (Less)

Pharmaceutical compositions containing vitamin d and calcium, their preparation and therapeutic use

Abstract: Described herein is a pharmaceutical composition containing Vitamin D and calcium, comprising a binding agent chosen from among the group consisting of: propylene glycol, a polyethylene glycol presenting a molecular weight comprised between 300 and 1500, liquid paraffin or silicone oil, useful for the treatment of nutritional deficiency of calcium and Vitamin D in the elderly.

A novel in vitro bladder pelvic nerve afferent model in the rat

Abstract: Objective To develop an in vitro model to allow electrophysiological recordings from pelvic nerve afferents of the urinary bladder in the rat and to ascertain the stability and reproducibility of the model with time. Materials and methods Six male Wistar rats (body weight ≈100 g) were used in the study. The bladder (complete with accessory organs of prostate and seminal vesicles), urethra and penis, together with the attached pelvic nerve and L6/S1 nerve trunk, were removed intact and placed in a specially designed recording chamber containing oxygenated Krebs solution maintained at 30 °C. The bladder was catheterized urethrally and attached to a continuous-infusion pump and a pressure transducer. The L6/S1 nerve trunk was placed across a silicone-gel wall into a separate chamber containing liquid paraffin, in which multiunit recordings from pelvic nerve afferents originating from the bladder were made. The afferent nerve activities in response to repeated bladder distension with saline, at 0.04 mL/min for 8 min over 3 h, were compared using the paired t-test to assess the reproducibility of the model. Conduction velocity studies were also carried out to ascertain the proportion of C- and Aδ-fibres in the multiunit recordings. Results Repeated bladder distension with saline over 3 h produced consistent and reproducible afferent nerve responses, signifying that the afferent nerves recorded in this study neither sensitize nor desensitize over time. This is an essential prerequisite when using this model to study the effects of pharmacological manipulation of the bladder on its afferent nerve response. Conduction velocity studies showed that ≈30% of the afferent fibres recorded from were C-fibres with the remaining being Aδ-fibres. Conclusions An in vitro bladder pelvic nerve afferent model for the rat was developed successfully; it is stable and produces reproducible results with repeated bladder distension over at least 3 h.

Therapeutic effect and pharmacokinetics of ketotifen transdermal delivery system.

Abstract: Ketotifen transdermal delivery systems were prepared using polyisobutylene, liquid paraffin, and fatty acid. In vitro skin penetration studies were conducted in Franz diffusion cells using excised porcine skin to determine the skin permeation rates of ketotifen patches. A trend of increased skin penetration of ketotifen was observed as the amount of liquid paraffin in the patch was increased. In addition, we found that lauric acid was a suitable enhancer for percutaneous absorption of ketotifen. Challenge tests were performed in guinea pigs to determine the therapeutic effect of the delivery systems for the inhibition of anaphylactic shock using varied concentrations of chicken ovum albumin as sensitizer. Our results showed that compared with the treatment of intramuscular administration, the skin patch was more effective and produced higher survival rates. The pharmacokinetics of the ketotifen patch were determined by applying the skin patch to the dorsal skin of rabbits. The plasma levels were maintained constant (42.5-36.4 ng/ml) from 9 to 30 hr. From our study, the prepared ketotifen patch may further be developed for the treatment or prevention of allergic asthma.

Reduction of Nitrate to Ammonium in Selected Paddy Soils of China *1

Abstract: Three paddy soils were examined for their capacities of dissimilatory reduction of nitrate to ammonium (DRNA). 15 N labelled KNO 3 was added at the rate of 100 mg N kg -1 . Either glucose or rice straw powder was incorporated at the rate of 1.0 or 2.0 mg C kg -1 respectively. Three treatments were designed to keep the soil saturated with water: A) a 2 cm water layer on soil surface (with beaker mouth open); B) a 2 cm water layer and a 1 cm liquid paraffin layer (with beaker mouth open); and C) water saturated under O 2 free Ar atmosphere. The soils were incubated at 28 oC for 5 days. There was almost no 15 N labelled NH + 4 N detected in Treatment A. However, there was 1.4 to 3.4 mg N kg -1 15 N labelled NH + 4 N in Treatment B and 2.1 to 13.8 mg N kg -1 in Treatment C. Glucose was more effective than straw powder in ammonium production. Because there was sufficient amount of non labelled NH + 4 N in the original soils, 15 N labelled NH + 4 N produced as such should be the result of dissimilatory reduction. Studies on microbial population showed that there were plenty of bacteria responsible for DRNA process (DRNA bacteria) in the soils examined, indicating that number of DRNA bacteria was not a limiting factor for ammonium production. However, DRNA bacteria were inferior in number to denitrifiers. DRNA process in soil suspension seemed to start after 5 days of incubation. Glycerol and sodium succinate, though both are readily available carbon sources to organisms,did not facilitate DRNA process. DRNA occurred only when glucose was available and at the C/NO 3 - N ratio of over 12. It seemed that both availability and quality of the carbon sources affected DRNA.

Friction and wear behaviors of several polymers under oil-lubricated conditions

Abstract: The friction and wear properties of polytetrafluoroethylene (PTFE), polyimide (PI), and polyamide 66 (PA66) sliding against GCr15 bearing steel under both dry and oil-lubricated conditions were studied by using an MHK-500 ring-block wear tester (Timken wear tester), and then Stribeck's curves of PTFE, PI, and PA66 under lubrication of the oil were given out. The worn surfaces of these polymers and the transfer films formed on the counterfaces were examined by using a scanning electron microscope (SEM) and an optical microscope, respectively. Experimental results show that the friction and wear-reducing properties of PTFE, PI, and PA66 can be greatly improved by lubrication with liquid paraffin, and the friction coefficients can be decreased by 1 order of magnitude compared to those in dry friction condition. Under lubrication of liquid paraffin, the friction coefficients of PTFE, PI, and PA66 decrease with the increase of load, but the wear increases with the increase of load. The variations of friction coefficients with load for PTFE, PI, and PA66 under lubrication of liquid paraffin can be described properly by the Stribeck's curves, as given out in this article. Under higher loads and sliding speeds in liquid paraffin lubrication, the friction and wear reducing properties of PA66 are the best, and those of PTFE are the worst; therefore, PA66 is also very suitable for applications in oil-lubricated conditions. Meanwhile, SEM and optical microscope investigations show that the wear and transfer of PTFE, PI, and PA66 can be greatly reduced by lubrication of liquid paraffin, but they still take place. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 68: 2175–2182, 1998

Heat conductive material

Abstract: thermally conductive material having excellent flexibility high thermal conductivity, providing no possibility of heat-conducting material which leads to electrical contacts disorder. A heat conductive material of the present invention, the synthetic resin material as a base material, adding hydrate of metal compound as the thermally conductive filler is a mixture. Thermally conductive filler, Aluminum hydroxide, magnesium hydroxide, zinc hydroxide, calcium hydroxide, tin hydroxide, and the like other metal hydrate. The substrate is a synthetic rubber, EPDM, butyl rubber, chloroprene rubber, acrylic rubber, nitrile rubber, fluorocarbon rubber, chlorosulfonated polyethylene rubber, styrene - butadiene rubbers are preferred. Also, oil may be added to increase flexibility. The oil, process oil, liquid paraffin, fatty oil, chlorinated paraffin, ester plasticizers, liquid rubbers, Liquid butadiene, and hydrocarbon-based synthetic lubricating oils are preferred.

Study of the tribochemical behavior of Al ion-implanted pure iron lubricated with ZDDP

Abstract: Friction and wear tests of unimplanted and Al ion-implanted pure iron specimens were carried out under lubrication conditions with liquid paraffin or liquid paraffin containing 2 wt% zinc dialkyldithiophosphate (ZDDP). The friction and wear data were analyzed, and the worn surfaces were characterized using Auger electron spectroscopy and X-ray photoelectron spectroscopy. It was found that Al ion implantation, with liquid paraffin as a lubricant, increased the wear resistance of pure iron by a factor of 50–70%. It was considered that the increase in wear resistance was due to the increase in surface residual compressive stress and microhardness induced by the implantation. The existence of oxide (Al 2 O 3 ) film on the surface of the ion-implanted specimen also has a favorable effect on the wear resistance for its antiadhesion and antiscuffing action. When ZDDP was added to liquid paraffin the wear resistance of both Al ion-implanted and unimplanted specimens was enhanced, but the wear resistance of the former was inferior to that of the latter. It was believed that the wear of the specimen was controlled by composition and amount of the antiwear reaction film, and the mechanical strengthening induced by Al ion implantation played a less important role in affecting the wear rate than the tribochemical effects on wear. The existence of Al element in the implanted pure iron retarded the reactions of iron with active elements S and Zn decomposed from the additive, reduced the amount of surface antiwear film formed during the wear process and changed the composition of the films.

Basic fibroblast growth factor impregnated hydrogel microspheres for embolization of cerebral arteriovenous malformations

Abstract: To assess the prevention of recanalization at embolized sites in cerebral arteriovenous malformations, the authors devised a novel embolic material, hydrogel microspheres prepared from poly(ethylene glycol) diacrylate impregnated with basic fibroblast growth factor. In this article, preparation of the microspheres, and preliminary study of in vitro and in vivo performance are discussed. Poly(ethylene glycol) diacrylate, prepared from end capping of poly(ethylene glycol) (molecular weights, 1,000, 2,000, and 4,000) with acryloyl chloride and benzophenone derived poly(ethylene glycol), prepared from poly(ethylene glycol) (molecular weight, 2,000) with benzoyl benzoic acid chloride as a photoinitiator, were dissolved in a buffer solution with or without basic fibroblast growth factor. The mixed solution was dropped stepwise into liquid paraffin with stirring. Ultraviolet light irradiation resulted in the formation of relatively rigid hydrogel microspheres (diameter, 100-400 microm). The in vitro study showed that the higher the molecular weight of poly(ethylene glycol) diacrylate used, the faster the release rate of immobilized protein. Canine kidneys were embolized with these microspheres via the femoral artery using a microcatheter. Histologic examination showed that microspheres occluded arterioles. The degree of accumulation of fibroblasts and extracellular matrix were larger for basic fibroblast growth factor impregnated microspheres than for nonimpregnated ones. Basic fibroblast growth factor released from microspheres may help regenerate tissues at arteriovenous malformation sites, and recanalization is expected to be prevented.

Heat storage composition and heat storage container

Abstract: PROBLEM TO BE SOLVED: To obtain a composition, which has no lowering in amount of latent heat of fusion, by comprising a hydrated salt-type heat storage material, a supercooling inhibitor, a thickener, water, a heat transfer promoter, and a water evaporation inhibitor. SOLUTION: This composition comprises 100 pts.wt. of a hydrated salt-type heat storage material such as sodium acetate trihydrate salt or the like, 1 to 5 pts.wt. of a supercooling inhibitor such as lithium fluoride or the like, 1 to 6 pts.wt. of a thickener, 1 to 10 pts.wt. of a heat transfer promoter selected from silicon carbide, boron oxide, carbon or the like, and 1 to 6 pts.wt. of water, or 1 to 5 pts.wt. of a water evaporation inhibitor such as liquid paraffin. In the composition, the crystal state of the hydrate-type heat storing material is maintained, so that the composition has no lowering in amount of latent heat of fusion. As the thickener, there are used combinations of polyvinyl alcohol, polyethylene glycol, gelatin, polymethyl cellulose sodium and sodium alginate. A heat storage container has the heat storage composition sealed in a metallic container, and heat transfer portions projecting toward the inside of the composition are provided to increase a heat transfer area thereby enhancing thermal conductivity.

Hair-dyeing agent composition

Abstract: PROBLEM TO BE SOLVED: To obtain the subject composition excellent in hair dyeing effect and fastness, and little causing uneven dyeing and staining the skin by incorporating chloroxylenol and/or chlorobutanol. SOLUTION: This hair dyeing agent composition is obtained by incorporating a dye, 0.01 to 2wt.% of chloroxylenol and/or chlorobutanol, and other ingredients, as required, e.g. a higher alcohol, liquid paraffin, ester oil, fatty acid, silicone (or its derivative), vaseline, polyhydric alcohol, ultraviolet ray absorber, antiseptic, surface active agent, thickening agent, pH adjustor, alkaline agent, perfume and pearling agent. The dye for this composition is an oxidation dye composed of a major intermediate (e.g. paraphenylenediamine) and coupler (e.g. resorcin), or direct dye (e.g. colorant Black No.401). The composition can be prepared into a formulation in the form of liquid, emulsion, cream, gel, paste, aerosol foam or the like.

Multiple organ dysfunction syndrome (MODS) after an intravenous injection of lamp oil (liquid paraffin)

Abstract: Sir: A recent letter by Waldhausen et al. [1] highlights the possible role of parenteral nutrition in the pathogenesis of critical illness polyneuropathy (CIP). A clinical study performed by the authors showed that CIP occurred only in patients receiving parenteral nutrition, and that early cessation of nutrition support could reduce the severity and duration of CIP. The proposed mechanism for the nutrition-induced axonal injury is glucose-induced depletion of intracellular phosphate stores with subsequent depletion of high-energy phosphate compounds. We wish to add another possible source of nutrition-induced injury, i. e., the oxidative modification of dietary lipids [2]. The lipid component of parenteral and enteral feedings is a mixture of polyunsaturated fatty acids (PUFAs) derived from vegetable oils. Dietary PUFAs are readily oxidized (the oxidative decomposition of PUFAs is responsible for rancidity in decaying foods), and infusion of PUFAs in an oxidation-prone condition like sepsis and multiple organ failure can have several deleterious consequences that would favor the development of CIP. The oxidative modification of circulating lipids is damaging to the vascular endothelium [3], and this effect could promote widespread microvascular injury and ischemic axonal injury. Oxidative modification of exogenous lipids can also promote peroxidative injury in lipid-rich structures such as cell membranes and axon sheaths [4]. Finally, infusion of dietary lipids can stimulate the production of inflammatory cytokines [5], and this effect will magnify the risk of inflammatory-mediated cell injury. The deleterious effects of lipid infusions are readily apparent in the animal model of the acute respiratory distress syndrome (ARDS) produced by infusion of oleic acid [6] (a PUFA that is abundant in intravenous lipid emulsions). Since CIP may share a common pathogenesis with ARDS, lipid infusions may have a similar ability to produce CIP. References

Friction and wear characteristics of copper and its compound-filled PTFE composites under oil-lubricated conditions

Abstract: Four kinds of polytetrafluoroethylene (PTFE)-based composites, such as pure PTFE, PTFE + 30(v)%Cu, PTFE + 30(v)%Cu2O, and PTFE + 30(v)%CuS composite, were prepared. Then the friction and wear properties of the PTFE composites filled with Cu, Cu2O, or CuS sliding against GCr15-bearing steel under both dry and liquid paraffin-lubricated conditions were studied by using an MHK-500 ring-block wear tester. Finally, the worn surfaces and the transfer films of these PTFE composites formed on the surface of GCr15-bearing steel were investigated by using a scanning electron microscope (SEM) and an optical microscope, respectively. Experimental results show that the antiwear properties of these PTFE composites can be greatly improved by filling Cu, Cu2O, or CuS to PTFE, and the wear of these PTFE composites can be decreased by two orders of magnitude compared to that of pure PTFE under dry friction conditions. Meanwhile, CuS increases the friction coefficient of the PTFE composite, but Cu and Cu2O reduce the friction coefficients of the PTFE composites. However, the friction and wear properties of Cu, Cu2O, or CuS-filled PTFE composites can be greatly improved by lubrication with liquid paraffin. The friction coefficients of these PTFE composites can be decreased by one order of magnitude compared to those under dry friction conditions, while the wear of these PTFE composites can be decreased by one to two orders of magnitude. The PTFE + 30(v)%Cu composite exhibits excellent friction and wear-reducing properties under higher loads in liquid paraffin-lubricated conditions, so the PTFE + 30(v)%Cu composite is much more suitable for application under oil-lubricated conditions in practice. Optical microscope investigation of transfer films shows that Cu, Cu2O, and CuS enhance the adhesion of the transfer films to the surface of GCr15-bearing steel, so they greatly reduce the wear of the PTFE composites. However, the transfer of the PTFE composites onto the surface of GCr15-bearing steel can be greatly reduced by lubrication with liquid paraffin, but the transfer still takes place. SEM examination of worn surfaces shows that the interaction between liquid paraffin and the PTFE composites, especially the absorption of liquid paraffin into the surface layers of the PTFE composites, creates some cracks on the worn surfaces of Cu2O or CuS-filled PTFE composites, the creation and development of the cracks reduces the load-carrying capacity of the PTFE composites; this leads to the deterioration of the friction and wear properties of the PTFE composites under higher loads in liquid paraffin lubrication. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 70: 1455–1464, 1998

Development of a new cellulose triacetate membrane with a microgradient porous structure for hemodialysis.

Abstract: Dialytic performance and biocompatibility of a newly developed cellulose triacetate (CTA) membrane with a microgradient porous structure, produced without using polyvinylpyrrolidone (PVP) and liquid paraffin, were compared with those of a conventional polysulfone (PS) membrane dialyzer. In vitro and clinical results demonstrated no significant difference in the dialytic performance and biocompatibility of the two dialyzers, but the CTA dialyzer lost less albumin during dialysis than the PS. These results suggest that a CTA membrane dialyzer with a porous microgradient structure attained comparable performance and biocompatibility to PS, and the risk of albumin loss was suppressed by the new CTA membrane.

Porous polyolefin film and its application

Abstract: PROBLEM TO BE SOLVED: To obtain a high-strength porous film which can have both low bubble point and high liquid retentivity by forming one having a liquid paraffin retentivity above a specified value and a bubble point below a specified value and obtain a hydrophilic porous film by imparting hydrophilicity to this porous film. SOLUTION: The liquid paraffin retentivity is at least 40%, and the bubble point is at most 2.0 kg/cm . The polyolefin is obtained by polymerizing at least one of ethylene, propylene and 4-8C α-olefins through, e.g. slurry polymerization. It preferably comprises a copolymer of a combination of ethylene and a small amount of propylene or at least one of 4-8C α-olefins. The porous polyolefin film has a thickness of 10-120 μm, a porosity of 40-90% and a tensile strength of at least 10 kg/5 cm, and it is obtained by boring at least 0.01/cm through holes of a surface hole diameter of 10-200 μm in a feedstock porous film having a maximum pore diameter measured with mercury porosimeter of at most 10 μm and a piercing strength of at least 200 g.