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The electroclinic effect in the smectic A phase of ferroelectric liquid crystals is a sensitive probe for measuring the soft
mode response near the A-C* transition point. It is possible to evaluate several coefficients of the Landau theory describing
the A-C* transition by simultaneously measuring the frequency dependence of both the optical signal and the current through
the sample. We have made such measurements on a couple of homologous series [2S,3S]-4′-(2-chloro-3-methyl pentanoyloxy) phenyl-trans-4″-n alkoxy cinnamates synthesized in our labortory. The results show that the Landau meanfield theory is adequate to describe
the A-C* phase transition in these compounds.
Presented at the 15th International Liquid Crystal Conference, Budapest, 3–8 July 1994. 相似文献
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Bi3+ ions substituting at Ba-sites in a limited concentration range with another donor dopant occupying the Ti-sites in polycrystalline BaTiO3 enhanced the positive temperature coefficient of resistance (PTCR) by over seven orders of magnitude. These ceramics did not require normal post sinter annealing or a change to an oxygen atmosphere during annealing. These ceramics had low porosities coupled with better stabilities to large applied electric fields and chemically reducing atmospheres. Bi3+ ions limited the grain growth to less than 8 m in size, they enhanced the concentration of acceptor-type trap centres at the grain-boundary-layer regions and maintained complete tetragonality at low grain sizes in BaTiO3 ceramics. 相似文献
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Food restriction was found to impair the incorporation of [1-14C]palmitate into myelin membrane lipids of developing rat brain. An attempt was made to determine whether this phenomenon
is due to differences in the rate of utilization of the labelled precursor or to its enhanced degradationvia β-oxidative pathways. Undernutrition in pups was imposed by food restriction during gestation and lactation. β-Oxidation
by brain region homogenates using [1-14C]palmitate was monitored at days 7, 14 and 21 of postnatal age. There was a significant increase in β-oxidation in the brain
regions of undernourished pups, with the cerebrum and cerebellum being more affected than the brain stem. Because developing
brain possesses the enzymic potential to utilize ketone bodies, the data may indicate increased usage of palmitate as an energy
source in the developing brain of undernourished animals. 相似文献
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Liliana Navarrete Jian Dou Drew M. Allen Rainer Schad Periaswamy Padmini Pranoti Kale R.K. Pandey 《Journal of the American Ceramic Society》2006,89(5):1601-1604
The morphology, structure, and magnetic properties of the magnetic semiconductor ceramic Ilmenite–Hematite (IH), (1− x )FeTiO3 – x Fe2 O3 , were studied as a function of the composition x . The magnetic ordering temperatures that we observed were consistently higher than those reported previously and were, for most of the composition range, above room temperature. We rule out the formation of Fe clusters as the origin of the magnetic properties. These magnetic properties of IH ceramics, in combination with their semiconducting characteristics, render them promising for spin-electronic applications. 相似文献
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Polyphenols and tannins in Indian pulses: Effect of soaking,germination and pressure cooking 总被引:1,自引:0,他引:1
Shweta Khandelwal Shobha A. Udipi Padmini Ghugre 《Food research international (Ottawa, Ont.)》2010,43(2):526-530
Polyphenols and tannins have implications for health and nutrition. There is limited information on their content in pulses, raw or post-processing. We estimated the concentrations of polyphenols and tannins in different cultivars of four pulses commonly consumed in India – Phaseolus aureus, Cajanus cajan, Lens esculenta and Cicer arietinum – and examined the effects of domestic processing. Means and standard deviations were calculated and results were analyzed by ANOVA. There were significant differences (P < 0.001) in the polyphenol and tannin contents of cultivars of the same pulse, with the exception of the tannin contents of pressure-cooked red gram cultivars (P = 0.3103). Processing reduced the concentrations of polyphenols by 19–59% and of tannins by 22–59%. A trend was observed in the degree to which processing reduced polyphenol and tannin contents (germination > pressure-cooking > soaking). Soaking, germination and pressure-cooking proved to be effective household strategies to reduce the levels of polyphenols and tannins in pulse-based foods, thereby enhancing the bioavailability of pulse protein. There is a need to determine the extent to which the remaining polyphenols and tannins are rendered unavailable by these processing techniques. 相似文献
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Jagruti V. Jadhav Padmini Anbu Sneha Yadav Amit P. Pratap Sandeep B. Kale 《Journal of surfactants and detergents》2019,22(3):463-476
Utilization of industrial waste as substrates for the rhamnolipid synthesis by Pseudomonas aeruginosa is a worthy alternative for conventionally used vegetable oils and fatty acids to reduce the production cost of rhamnolipid. Sunflower acid oil (SAO), a by-product of the oil industry, contains 70% 18:0 fatty acid, with oleic acid as a major component. In this scope, production and analysis of rhamnolipid was successfully demonstrated using SAO as a new substrate. Pseudomonas aeruginosa produced rhamnolipid (a glycolipid biosurfactant) at a maximum concentration of 4.9 g L−1 with 60 g L−1 of SAO in the medium. Structural properties of rhamnolipid biosurfactant are confirmed using thin layer chromatography (TLC), high performance liquid chromatography (HPLC), and fourier transformed infrared spectroscopy (FTIR) analysis. Further surface-active properties of the crude rhamnolipid were evaluated by measuring surface tension and emulsification properties. The synthesized rhamnolipid reduced the surface tension of water to 30.12 mN m−1 and interfacial tension (against heptane) to 0.52 mN m−1. Moreover, rhamnolipid shows the highest emulsification index (above 80%) for vegetable oils. This study confirms the use of SAO as a potential substrate for rhamnolipid production. The synthesized rhamnolipid was incorporated in liquid detergent formulation along with alpha olefin sulfonate (AOS) and sodium lauryl ether sulfate (SLES). The performance properties including foaming and cleaning efficiency of liquid detergent were compared. 相似文献
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Owen S. Fenton Katy N. Olafson Padmini S. Pillai Michael J. Mitchell Robert Langer 《Advanced materials (Deerfield Beach, Fla.)》2018,30(29)
Advances in biomaterials for drug delivery are enabling significant progress in biology and medicine. Multidisciplinary collaborations between physical scientists, engineers, biologists, and clinicians generate innovative strategies and materials to treat a range of diseases. Specifically, recent advances include major breakthroughs in materials for cancer immunotherapy, autoimmune diseases, and genome editing. Here, strategies for the design and implementation of biomaterials for drug delivery are reviewed. A brief history of the biomaterials field is first established, and then commentary on RNA delivery, responsive materials development, and immunomodulation are provided. Current challenges associated with these areas as well as opportunities to address long‐standing problems in biology and medicine are discussed throughout. 相似文献
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