Effect of undernutrition on the metabolism of phospholipids and gangliosides in developing rat brain

1. Phospholipid content of brains of 3- or 8-week-old undernourished rats was 7--9% less than that for the corresponding control animals and this deficit could not be made up by rehabilitation. Phosphatidyl ethanolamine and plasmalogen were the components most affected in brains of undernourished rats. 2. Incorporation of 32P into phospholipids by brain homogenates was 28% higher in 3-week-old undernourished rats. It is suggested that enhanced phospholipid metabolism in undernourished animals may be related to behavioural alterations noted previously (Sobotka, Cook & Brodie, 1974). 3. Ganglioside concentrations in 3- and 8-week-old undernourished animals were 14% and 11.5% less respectively than those of the control animals and this difference could be made up by rehabilitation. [14C]Glucosamine incorporation in vivo into brain gangliosides was not affected by undernutrition.

X-ray studies on crystalline complexes involving amino acids and peptides. XV. Crystal structures of L-lysine D-glutamate and L-lysine D-aspartate monohydrate and the effect of chirality on molecular aggregation

L-Lysine D-glutamate crystallizes in the monoclinic space group P2(1) with a = 4.902, b = 30.719, c = 9.679 A, beta = 90 degrees and Z = 4. The crystals of L-lysine D-aspartate monohydrate belong to the orthorhombic space group P2(1)2(1)2(1) with a = 5.458, b = 7.152, c = 36.022 A and Z = 4. The structures were solved by the direct methods and refined to R values of 0.125 and 0.040 respectively for 1412 and 1503 observed reflections. The glutamate complex is highly pseudosymmetric. The lysine molecules in it assume a conformation with the side chain staggered between the alpha-amino and the alpha-carboxylate groups. The interactions of the side chain amino groups of lysine in the two complexes are such that they form infinite sequences containing alternating amino and carboxylate groups. The molecular aggregation in the glutamate complex is very similar to that observed in L-arginine D-aspartate and L-arginine D-glutamate trihydrate, with the formation of double layers consisting of both types of molecules. In contrast to the situation in the other three LD complexes, the unlike molecules in L-lysine D-aspartate monohydrate aggregate into alternating layers as in the case of most LL complexes. The arrangement of molecules in the lysine layer is nearly the same as in L-lysine L-aspartate, with head-to-tail sequences as the central feature. The arrangement of aspartate ions in the layers containing them is, however, somewhat unusual. Thus the comparison between the LL and the LD complexes analyzed so far indicates that the reversal of chirality of one of the components in a complex leads to profound changes in molecular aggregation, but these changes could be of more than one type.

Effect of √-irradiation on the structure and dynamics of domains in triglycine selenate

A comparative study of the switching properties of pure and √-irradiated TGSe crystals has been carried out to see the effect of irradiation on the structure and dynamics of domains. The switching behaviour of √-irradiated TGSe has been found to be qualitatively similar to that of unirradiated crystal and this has been interpreted in terms of structural inhibition caused by the formation of radiolysis products as well as the difference between the domain structures of the unirradiated and irradiated samples. Confirmation of this has been obtained by studying the domain patterns using the etch method.

Effect of sintering on optical, structural and photoluminescence properties of ZnO thin films prepared by sol-gel process

Zinc oxide (ZnO) thin films have been deposited on glass substrates via sol-gel technique using zinc acetate dihydrate as precursor by spin coating of the sol at 2000 rpm. Effects of annealing temperature on optical, structural and photo luminescence properties of the deposited ZnO films have been investigated. The phase transition from amorphous to polycrystalline hexagonal wurtzite structure was observed at an annealing temperature of 400 degrees C. An average transmittance of 87% in the visible region has been obtained at room temperature. The optical transmittance has slightly increased with increase of annealing temperature. The band gap energy was estimated by Tauc's method and found to be 3.22 eV at room temperature. The optical band gap energy has decreased with increasing annealing temperature. The photoluminescence (PL) intensity increased with annealing temperature up to 200 degrees C and decreased at 300 degrees C. (c) 2010 Elsevier B.V. All rights reserved.

Effect of Temperature on Respiration of a Mesophilic and a Thermophilic Fungus

The respiratory rates of mycelia of the mesophilic fungus, Aspergillus niger, and the thermophilic fungus, Thermomyces lanuginosus, were comparable at their respective temperature optima for growth. The respiratory rate of A. niger was independent of changes in temperature between 15 and 40 C. The respiratory rate of T. lanuginosus increased with increase in temperature between 25 and 55 C.

Effect of GPS on understanding relationship between mobile map and environment : A field experiment

Objectives: GPS technology enables the visualisation of a map reader s location on a mobile map. Earlier research on the cognitive aspects of map reading identified that searching for map-environment points is an essential element for the process of determining one s location on a mobile map. Map-environment points refer to objects that are visualized on the map and are recognizable in the environment. However, because the GPS usually adds only one point to the map that has a relation to the environment, it does not provide a sufficient amount of information for self-location. The aim of the present thesis was to assess the effect of GPS on the cognitive processes involved in determining one s location on a map. Methods: The effect of GPS on self-location was studied in a field experiment. The subjects were shown a target on a mobile map, and they were asked to point in the direction of the target. In order for the map reader to be able to deduce the direction of the target, he/she has to locate himself/herself on the map. During the pointing tasks, the subjects were asked to think aloud. The data from the experiment were used to analyze the effect of the GPS on the time needed to perform the task. The subjects verbal data was used to assess the effect of the GPS on the number of landmark concepts mentioned during a task (landmark concepts are words referring to objects that can be recognized both on the map and in the environment). Results and conclusions: The results from the experiment indicate that the GPS reduces the time needed to locate oneself on a map. The analysis of the verbal data revealed that the GPS reduces the number of landmark concepts in the protocols. The findings suggest that the GPS guides the subject s search for the map-environment points and narrows the area on the map that must be searched for self-location.

Effect of pressure on the dielectric properties of DTAAP

Effect of pressure on the dielectric properties of ferroelectric DTAAP has been carried out upto about 4 Kbars. The dTc/dP value was found to be -1.65°C/Kbar. It was noted that the value of dTc/dP is 1.63 times smaller in DTAAP as compared to TAAP, where as Tc itself is 1.13 times larger.

Effect of V2O5 on the Surface and Structural Characteristics of Potassium Lithium Niobate

It has been suggested that materials with interesting and useful bulk non-linear optical properties might result by substituting vanadium, the lightest element in the group V of periodic table, for Nb or Ta atoms along with Li and three oxygens. It is with this motivation that we have been making attempts to grow single crystals of LiNbO3 doped with various concentrations of V2O5. Unfortunately the results obtained on the ceramic samples of this material have not been very encouraging, owing to their hygroscopic nature. However, our attempts to prepare both ceramic and single-crystalline samples of potassium lithium niobate (K3Li2Nb5O15; KLN) doped V2O5 were successful. In this letter we report the preliminary results concerning our studies on the effect of V2O5 doping on the structural as well as topographic features of both ceramic and single-crystalline samples of KLN.

Crystal structures of propanediamine complexed with L and DL- glutamic acid: effect of chirality on propanediamine.

The structures of complexes of 1,3-diaminopropane With L- and DL-glutamic acid have been determined. L-Glutamic acid complex: C3H12N22+.2C5H8NO4-, M(r) = 368.4, orthorhombic. P2(1)2(1)2(1), a = 5.199 (1), b = 16.832 (1). c = 20.076 (3) angstrom, V = 1756.6 (4) angstrom3, z = 4, D(x) = 1.39 g cm-3, lambda(Mo K-alpha) = 0.7107 angstrom, mu = 1.1 cm-1, F(000) = 792. T = 296 K, R = 0.044 for 1276 observed reflections. DL-Glutamic acid complex: C3H12N22+.2C5H8NO4-, M(r) = 368.4, orthorhombic, Pna2(1), a = 15.219(2), b = 5.169 (1), c 22.457 (4) angstrom, V = 1766.6 (5) angstrom3 Z = 4, D(x) = 1.38 g cm-3, lambda(Mo K-alpha) = 0.7107 angstrom, mu = 1.1 cm F(000) = 792, T = 296 K, R = 0.056 for 993 observed reflections. The conformation of diaminopropane is all-trans in the DL complex but trans-gauche in the L complex. The main packing feature in the L complex is the arrangement of diaminopropane around dimers of antiparallel L-glutamic acid molecules. The diaminopropane in the DL complex is sandwiched between two antiparallel glutamic acid molecules of the same chirality and this forms the basic packing unit. This might be the dominant form of interaction between L-glutamic acid and diaminopropane in solution. The structures reveal the adaptability of the polyamine backbone to different environments and the probable reasons for their choice as biological cations.

Switching studies and the effect of irradiation on ferroelectric properties of TAAP and DTAAP

Polarization switching processes in TAAP and DTAAP have been studied by the Merz method. The switching process in DTAAP is slower than in TAAP. The temperature dependence of switching time indicates that the crystal might contain groups of domain nuclei with different activation energies. X-ray irradiation causes an increase in the threshold field below which switching could not occur and decrease in the mobility of domain walls. Irradiation decreases the peak value of dielectric constant, Tc and increases the value of coercive field. Domain structure studies on TAAP crystals have shown that the crystals grow as both predominantly single domain and multi domains, depending on which the internal bias increases or remains unaffected upon irradiation.