Showing papers on "Liquid paraffin published in 1973"
TL;DR: In this paper, a rapid response time-resolved E.S.R. spectrometer has been used to observe the decay of an emission spectrum into the corresponding absorption, and the effective relaxation time extracted by fitting an exponential curve to the early part of the decay, and then obtaining the true T 1 at any point of the spectrum by extrapolation to zero microwave power.
Abstract: Chemically induced electron polarization provides a new method for the direct determination of electron spin-lattice relaxation times of radicals in liquids. A rapid-response time-resolved E.S.R. spectrometer has been used to observe the decay of an emission spectrum into the corresponding absorption, and the effective relaxation time extracted by fitting an exponential curve to the early part of the decay, and then obtaining the true T 1 at any point of the spectrum by extrapolation to zero microwave power. The decay is monitored on resonance in the dispersion mode and at the points of maximum slope in the absorption mode : both results converge to T 1 at zero power with a gradient determined by T 2. Results for T 1 and T 2 on the benzophenone ketyl radical in liquid paraffin over a viscosity range 0·3 poise to 30 poise are reported. In this preliminary investigation the deuterated radical was used, and no attempt was made to resolve the hyperfine lines. The values of T 1 and T 2 for the modulation broad...
90 citations
TL;DR: In vitro preparations of locust Malpighian tubules can be made by a new technique in which the alimentary canal to which the tubules attach is removed from the insect and set up in Ringer's solution under liquid paraffin, suggesting an active transport of potassium.
72 citations
TL;DR: Observations of xylem cavitation in Ricinus plants using vibration detection provide considerable circumstantial evidence in justification of the new technique as already described and further developed.
Abstract: Xylem cavitation has been studied in Ricinus plants using vibration detection to examine its induction by different factors. These observations provide considerable circumstantial evidence in justification of the new technique as already described and further developed. In general cavitation is induced only when the tissue water balance is reduced hydrostatically. Thus cavitation is promoted by intense radiation which enhances transpiration, or alternatively by the blockage of xylem conduits by suspended particles carried in the transpiration stream. In contrast a reduction in radiation, or prevention of transpiration tends to restrict cavitation. Thus cavitation can be prevented by immersing a leaf in liquid paraffin. This technique has been used to see if radioactive bombardment would trigger its induction but no detectable effect has been observed even when exposed to intense radiation.An excised leaf, losing water in air, produces a "click total". On restoration to full turgor by standing the petiole in water it recovers very slowly and subsequently its "click total" is much reduced. If however the newly wilted leaf is allowed to recover in water following gas evacuation treatment the "cavitation total" often approaches the original and the rate of recovery is extremely rapid. Apparently gas emboli develop rapidly in conduits which have cavitated, but they can be removed by vacuum injection: the conduits refill and conduction is restored.
67 citations
TL;DR: The ability of the spermatozoa incubated in albuminfree BMOC-2 to enter zona-free hamster eggs was investigated and showed that both groups of eggs were penetrated by spermatozosa as judged by the sperm chromatin dispersion.
Abstract: Yanagimachi (1972a) published the first report ofcapacitation in vitro of guinea\x=req-\ pig spermatozoa. He incubated the spermatozoa in a medium developed by Biggers, Whitten & Whittingham (1971). After 12 to 18 hr incubation, the spermatozoa showed evidence of the acrosomal reaction and were able to penetrate guinea-pig eggs in vitro, with subsequent dispersion of the sperm head and pronuclear formation. So far, all the systems assayed for capacitation in vitro of mammalian spermatozoa have in their composition complex macromolecules such as those present in the body fluids or blood serum fractions. We decided to undertake a further investigation of the conditions under which guinea-pig spermatozoa would undergo capacitation. For this purpose, the epididymal tails were removed from adult guinea-pigs and the epididymal spermatozoa were suspended in 0\m=.\9%sodium chloride. From this sperm suspension, samples of spermatozoa were placed in 100 \g=m\lBMOC-2 medium (Brinster, 1965) devoid of macromolecules. The final sperm concentration was 2x 104 spermatozoa/μ . The drop of medium containing the spermatozoa was covered with liquid paraffin and incubated at 37° C for a period of 14 to 18 hr. At the end of the incubation period, the spermatozoa were examined with a phase-contrast microscope and nearly 100% of the spermatozoa showed evidence of acrosomal reaction. During the incubation, the pattern of motility changed. The characteristic motility pattern of activated spermatozoa, similar to that described by Yanagimachi (1970a) for hamster spermatozoa, was assumed by the guinea-pig spermatozoa. Since capacitated guinea-pig spermatozoa can enter zona-free hamster eggs (Yanagimachi, 1972b), the ability of the spermatozoa incubated in albuminfree BMOC-2 to enter zona-free hamster eggs was investigated. Eggs were recovered from the oviduct of superovulated hamster females and allocated to two groups. The eggs in one group were made zona-free in BMOC-2 and those in the other group were made zona-free in the saline fraction of BMOC-2. Both groups of eggs were mixed in a Petri dish with the capacitated guinea-pig spermatozoa and incubated at 37° C for a further 2 hr. The results (Table 1 ) showed that both groups of eggs were penetrated by spermatozoa as judged by the sperm chromatin dispersion (see PI. 1, Figs 1 and 2). A much smaller percentage of the eggs incubated in the albumin-free medi¬ um, however, were penetrated compared to those incubated in the medium containing albumin. The difference in the percentage of fertilization was due
55 citations
TL;DR: The glands of Myrmica rubra aggregate around a source of one of their secretions, which can be called ‘alarm pheromone’, and also around workers of Lasius flavus, and the mechanism of these aggregations differ.
49 citations
BP1
TL;DR: In this article, the metal cutting activities of mineral oil blends containing mixtures of organosulphur and organochlorine compounds are reported, and it appears that this was associated with the production in the system of the iron salt of the other element.
34 citations
Patent•
08 Aug 1973TL;DR: In this paper, a process for producing powdered paraffin is described, which is characterized by comprising the steps of heating the liquid Paraffin to a temperature between 50*C and 70*C, spraying the liquid PARF into a high velocity flow of cold air, maintaining the mixture until the paraffIN solidifies, and separating the powdered PARFIN from the air.
Abstract: This invention relates to a process for producing powdered paraffin, characterized by comprising the steps of heating the liquid paraffin to a temperature between 50*C and 70*C, spraying the liquid paraffin into a high velocity flow of cold air, maintaining the mixture until the paraffin solidifies, and separating the powdered paraffin from the air, discharging the paraffin for further operations.
10 citations
TL;DR: The highest incidence of deaths occurred in intact rats of both sexes treated with aflatoxin, and hepatomas were found in all 4 survivors among these animals.
8 citations
Abstract: The relevance of diamagnetic susceptibility as a tool for the structure analysis of solid high polymers is stressed in the light of some new examples. The present results complement previous data and offer new aspects on the diamagnetic investigations of longchain hydrocarbons, especially polyethylene (PE). The molecular susceptibility is proportional to the average number of repeat units in the chain. The proportionality factor defines an intermolecular constant μk which characterizes different physical states. This was found to be 2.5 × 10−6 for the liquid and 3.5 × 10−6 cgs for the crystalline state of paraffins and polyethylene (solution-crystallized). For melt-crystallized material, μk, approaches the typical value of the liquid paraffin in agreement with previous results. Such a low μk is probably related to the increased disorder of the paracrystalline lattice domains, in contrast to the more ordered microparacrystallites in the so-called “single crystals,” where μk = 3.5 × 10−6. In single crystals of branched PE, μk approaches 2.5 × 10−6 with increasing branching ratio. Like paraffins in the gaseous state, molten PE, with chains longer than 1000 A, has μk = 0. If the solution-crystallized material is molten for 10 min and thereafter cooled, μk retains the original value 3.5 × 10−6 cgs characteristic of the crystalline state. Hence, solution-crystallized polyethylene apparently possesses a kind of “memory.” Such a “memory” can, nevertheless, be partly destroyed when molten PE is stirred for 10 min and then quenched. Aggregates of solution-precipitated crystals with 3% branching concentration give μk = 2.9 ± 0.2 × 10−6 in good agreement with x-ray diffraction data. Finally, experimental details on the magnetic measurements are critically discussed, and various aspects of improvements for further investigations are also described.
5 citations
TL;DR: In this paper, the state of water contained in emulsions, particularly in o/w emulsion, was studied as a model of water orientation at the peripheries of biomembranes.
Abstract: The state of water contained in emulsions, particularly in o/w emulsions, was studied as a model of water orientation at the peripheries of biomembranes. Dielectric measurements made at microwave frequency on emulsions containing water and liquid paraffin in various ratios with emulsifiers revealed that the o/w emulsions possessed considerably reduced dielectric loss as compared with theoretical values obtained in accordance with the Maxwell-Wagner model, while the dielectric properties of w/o emulsion were in good agreement with the theoretically expected values. The observations seem to be explained by assuming changes in the state of water in the oil-water interfacial layer in o/w emulsions. The preparation of stable emulsions for use in this study is also discussed.
5 citations
Journal Article•
TL;DR: In this article, a method is described for coping with increasing tension on soft clays without the use of RUBBER MEMBTRANES by using LIQUID PARAFFIN as the CELL fluid.
Abstract: A METHOD IS DESCRIBED FOR CONDUCTING EXTENSION TESTS UNDER DECREASING EFFECTIVE STRESSES ON SOFT CLAYS WITHOUT THE USE OF RUBBER MEMBTRANES. TRIAXIAL COMPRESSION TESTS ON PLASTIC CLAYS MAY BE CONDUCTED ON FINE GRAINED SOILS AND ESSENTIALLY THAT OF THE PORTION WITH REDUCED CROSS SECTION. BY USING LIQUID PARAFFIN AS THE CELL FLUID ON UNJACKETED SAMPLES OF CLAY. THIS IS POSSIBLE BECAUSE OF THE DIFFERENCE IN SURFACE TENSIONS AND INTERFACIAL CONTACT ANGLES BETWEEN THE PORE WATER IN THE SAMPLE AND THE SURROUNDING PARAFFIN. IN THE CASE OF EXTENSION TESTS WITH REDUCED AXIAL STRESS, KEEPING LATERAL STRESS CONSTANT IS A PROBLEM. PARAFFIN WILL INTRUDE INTO THE JUNCTION BETWEEN THE END CAPS AND THE SAMPLE ENDS AS SOON AS THE VERTICAL STRESS AT THE ENDS BECOMES LESS THAN LATERAL PRESSURE. SEVERAL TRIALS LED TO THE ADOPTION OF NEOPRENE RUBBER MEMBRANE AS SLEEVING AT THE END OF THE SAMPLE. HIGH VACCUM SILICONE GREASE IS USED TO SEAL THE JUNCTION BETWEEN THE SLEEVINGS AND SAMPLE. IT IS IMPORTANT THAT THE RUBBER MEMBRANE BE OF THE CORRECT DIAMETER. DETAILS OF THE TESTS ARE GIVEN. THE SAMPLES WERE TRIMMED IN STAGES FROM 95 MM DIAMETER TUBE SAMPLES BY USING A SPECIAL TRIMMING FRAME HAVING THE PROFILE OF THE SAMPLE. TWO SETS OF SAMPLES WERE USED. COMPARISON TESTS WERE CONDUCTED WITH SAMPLES COVERED WITH HORIZONTAL FOLDS. CELL PRESSURES EMPLOYED VARIED FROM 0.05 KG/CENTIMETER SQUARED TO 0.20 KG/ CENTIMETER SQUARED. THE AXIAL STRESS WAS REDUCED IN STRESS CONTROLLED DECREMENTS THROUGH A LOADING FRAME. DRAINAGE OF THE SAMPLE WAS ALLOWED AT THE TOP AND BOTTOM ENDS. DEFORMATIONS WERE MEASURED AT THE TOP BY A DIAL GAGE. FOR THE PURPOSE OF STRAIN COMPUTATION, IT WAS PRESUMED THAT THE TOTAL DEFORMATION OF THE SAMPLE WAS
TL;DR: The form and behaviour of the sporangiophores of Pilaira anomala, P. caucasica and P. moreaui differed between species and the stages of development resembled both Phycomyces and Pilobolus and the duration of these stages varied between the species.
Abstract: The form and behaviour of the sporangiophores of Pilaira anomala, P. caucasica and P. moreaui were examined. The stages of development resembled both Phycomyces and Pilobolus and the duration of these stages varied between the species. Rates of growth of the sporangiophores were measured. ‘Stolons’ were formed by abortive sporangiophores under conditions of unfavourable nutrition. The pattern of curvature of sporangiophores during positive phototropism in air and its reversal under liquid paraffin resembled Phycomyces.
TL;DR: In this paper, the dielectric relaxation of six rigid polar solute molecules over a 40°C temperature range (20-60°C) has been studied as a function of the solvent composition (benzene + liquid paraffin mixtures).
Abstract: The dielectric relaxation of six rigid polar solute molecules over a 40°C temperature range (20–60°C) has been studied as a function of the solvent composition (benzene + liquid paraffin mixtures).The thermodynamics of the relaxation processes are examined, compared with corresponding results for viscous flow of the solvents, and inferences drawn about the structure of the solvent and the nature of the relaxation process.The effects of solute dimensions and solvent viscosity upon the relaxation times are examined and an equation proposed to relate these factors.
TL;DR: In this paper, a simplified method has been used as compared to the commonly used one of brushing with liquid paraffin to facilitate the removal of gunpowder residues from the skin, and the results clearly show that from the content of Sb, primarily, and also of Ba, it is possible to identify the person who fired the pistol.
Abstract: In an attempt to facilitate the removal of gunpowder residues from the skin, a simplified method has been tested as compared to the commonly used one of brushing with liquid paraffin. The removing material is still paraffin, but it is dropped from a lighted paraffin candle onto the first interdigital space of the hand. Maps were constructed for gunpowder residues on hands after pistol firing and the first interdigital space was found to be the most significant. Analysis of paraffin “blanks” from candles showed them to be free from antimony, barium and copper. Many samples were examined from the left and the right hands of individuals who had or had not fired a pistol. The results clearly show that from the content of Sb, primarily, and also of Ba, it is possible to identify the person who fired the pistol. Due to the random distribution of copper coming from the skin, this element appears not to be meaningful for the identification of pistol firers. Some practical cases of suicides and shootings are reported.
TL;DR: Fecal paraffin was highly correlated with fecal fatty acids, total nitrogen, dry matter, and ash, and Digestibility coefficients from total fecal collection correlated well with the mean digestibility coefficient from paraffIn of samples collected 4, 8, and 12 h after feeding.
TL;DR: Explantas de fruta de limón manifestan semejanto nucleolar comportamiento, cuanádo están incubadas en parafina liquida con, y sin auto-oxidantes.
Abstract: Explantas de fruta de limon manifestan semejanto nucleolar comportamiento, cuanado estan incubadas en parafina liquida con, y sin auto-oxidantes.
TL;DR: The following seven compounds were prepared, R-N=C-NH-_??_+SO3Na R : n-pentyl (1), n-heptyl (2), nonyl (3), nundecyl (4); n-tridecyl (5); n -pentadecyl (6); nhexyl (7), and their physico-chemical properties in aqueous solutions were studied.
Abstract: The following seven compounds were prepared, R-N=C-NH-_??_+SO3Na R : n-pentyl (1) : n-heptyl (2); n-nonyl (3); n-undecyl (4); n-tridecyl (5); n-pentadecyl (6); n-heptadecyl (7), and their physico-chemical properties in aqueous solutions were studied.The results obtained were as follows.1) Surface-active abilities such as reduction of surface tension, emulsification of liquid paraffin, solubilization of Orange OT, deflocculation of calcium carbonate and wet-through to the cotton cloth were observed in the aqueous solutions of sample (3), (4), (5), (6) and (7).2) Sample (6) and (7) appear to be excellent dispersants for various dyes and pigments.
01 Jan 1973
TL;DR: The diffusion coefficient of triplet anthracene in n-hexadecane (20 − 90 C) and nhexane (25 C) was measured with the modified Avakian-Merrifield method as discussed by the authors.
Abstract: The diffusion coefficient D of triplet anthracene in n-hexadecane (20 – 90 C) and n-hexane (25 C) was measured with the modified Avakian-Merrifield method For n-hexadecane large deviations from the Stokes-Einstein equation are found With the experimental values of D the rate constants for diffusion-limited triplet-triplet annihilation are calculated for both solvents and compared with experimental values In n-hexane triplet-triplet annihilation is slower than diffusion controlled