Solute induced liquid crystalline behaviour of a quaternary ammonium salt and its application to structure determination

A new liquid crystalline phase, induced by the addition of small amounts of a non-mesogenic solute (such as dimethyl sulphoxide or methyl iodide) to a quaternary ammonium salt, N-methyl-N,N,N-trioctadecylammonium iodide (MTAI), has been detected by NMR and optical microscopic studies. In some cases, there is a coexistence of nematic and smectic phases. Information on the ordering of the phases in the magnetic field of the spectrometer has been derived from NMR spectra of a dissolved molecule, C-13-enriched methyl iodide. The low order parameter of the pure thermotropic nematic phase of the salt provides first-order spectra of the dissolved oriented molecules. Analyses of spectra of cis,cis-mucononitrile exemplifies the utility of the MTAI nematic phase in the determination of structural parameters of the solute.

Gossypol-induced hypokalemia and role of exogenous potassium salt supplementation when used as an antispermatogenic agent in male langur monkey

In our earlier study, we have observed that hypokalemia in langur monkeys, following gossypol acetic acid (GAA) treatment (5 mg dose level) when used as an antispermatogenic agent, and potassium salt supplementation partially maintained body potassium level of the animals. The aims of the present investigation was to confirm further occurrence of hypokalemia in the monkey (comparatively at two higher dose levels) and the role of potassium salt in preventing occurrence of gossypol-induced hypokalemia. Highly purified gossypol acetic acid alone at two dose levels (7.5 and 10 mg/animal/day; oral) and in combination with potassium chloride (0.50 and 0.75 mg/animal/day; oral) was given for 180 days. Treatment with gossypol alone as well as with the supplementation of potassium salt resulted in severe oligospermia and azoospermia. Animals receiving gossypol alone showed significant potassium deficiency with signs of fatigue at both dose levels. Enhanced potassium loss through urine was found in potassium-deficient animals, whereas animals receiving gossypol acetic acid plus potassium salt showed normal serum potassium with a less significant increase in urine potassium level during treatment phases. Other parameters of the body remained within normal range except gradual and significant elevation in serum transaminases activity. The animals gradually returned to normalcy following 150 and 180 days of termination of the treatment.

Consolidation Behavior of Soils

Based on Terzaghi's consolidation theory, percent of consolidation, U, versus the time factor, T, relationship for constant/linear excess pore water pressure distribution, it is possible to generate theoretical log10(H2/t) versus U curves where H is the length of the drainage path of a consolidating layer, and t is the time for different known values of the coefficient of consolidation, cν. A method has been developed wherein both the theoretical and experimental behavior of soils during consolidation can be simultaneously compared and studied on the same plot. The experimental log10(H2/t) versus U curves have been compared with the theoretical curves. The deviations of the experimental behavior from the theory are explained in terms of initial compression and secondary compression. Analysis of results indicates that the secondary compression essentially starts from about 60% consolidation. A simple procedure is presented for calculating the value of cv from the δ-t data using log10(H2/t) versus U plot.

Critical Reappraisal Of Plasticity Index Of Soils

A fundamental approach, based on Gouy-Chapman theory of double layer, has been provided to micromechanistically interpret the plasticity index of soils and their relationship with liquid limit. The relationships between plasticity index and liquid limit, developed earlier, through statistical approaches and critical state concepts, have been reexamined. The statistical analysis of extensive published data has resulted in the relationship, IP = 0.74 (wL - 8). On comparison with other relationships in vogue the proposed equation has been found to give better agreement. From the reappraisal of critical state approaches consistent with the micromechanistic interpretation, the possible range of parameters have been computed and compared with those obtained by statistical means to enhance the credibility of the proposed relationship.

Structure of the Monosodium Salt of D-Glucose 6-Hydrogenphosphate

Na+.C6HI209 P-, Mr=282.1, monoclinic, e2~, a=5-762(1), b=7.163(2), c=12.313(1)A, fl= 99.97 (1) °, U= 500.5 A 3, Z= 2, D m = 1.86, D x = 1.87 Mg m -s, Cu Ka, 2 = 1.5418 A, /a = 3-3 mm -1, F(000) = 292, T= 300 K, final R for 922 observed reflections is 0-042. The phosphate ester bond, P-O(6), is 1.575 (5)A, slightly shorter than the P~O bond in monopotassium phosphoenolpyruvate [1.612 (6) A] [Hosur & Viswamitra (1981). Acta Cryst. B37, 839-843]. The pyranose sugar ring takes a 4C 1 chair conformation. The conformation about the exocyclic C(5)-C(6) bond is gauche-trans. The endocyclic C-O bonds in the glucose ring are nearly equal with C(5)-O(5) = 1.435 (8) and C(1)-O(5) = 1.436 (9) A. The sodium ion has seven near neighbours within a distance of 2.9 A. The crystal structure is stabilized by hydrogen bonds between the O atoms of symmetryrelated molecules.

Compressibility of Partly Saturated Soils

From the considerations of the truncated diffuse double layer due to partial saturation, an equilibrium equation is written in terms of the soil state parameter viz. void ratio, e, void ratio at liquid limit, e=wG, degree of saturation, S and external applied stress, p. The type of fine grained soil is subdued by its liquid limit. The viability of the formulated approach has been experimentally verified. This approach, essentially eliminates the difficulty in the measurement of pore air pressure, u pore water pressure, u and computation of \Gv parameter.

Structure of the disodium salt of glucose 1-phosphate hydrate, 2Na+.C6H11O9P2-.3.5H2O

Mr= 367.2, monoclinic, C2, a = 8.429 (1),b= 10.184(2), c= 16.570(2)A, /~= 99.18 (1) °, U= 1404.2 A 3, z = 4, D m = 1.73, D x = 1.74 Mg m -3,Cu K~, 2 = 1.5418 A, g = 2.99 mm -1, F(000) = 764,T= 300K, final R for 1524 observed reflections is0.069. The endocyclic C-O bonds in the glucose ring are nearly equal with C(5)-O(5)= 1.445 (10) and C(1)-O(5)= 1.424(10). The pyranose sugar ring adopts a 4C 1 chair conformation. The conformation about the exocyclic C(5)-C(6) bond is gauche-gauche, in contrast to gauche-trans observed in the structure of the dipotassium salt of glucose 1-phosphate. The phosphate ester bond, P-O(1), is 1.641 (6)A, slightly longer than the 'high-energy' P-,.O bond in the monopotassium salt of phosphoenolpyruvate [1.612 (6)A]. Two sodium ions are six coordinated while the third has only five neighbours.

The structure of the monobarium salt of glucose 6-phosphate heptahydrate

Abstract is not available.

A Note on the Determination of Plastic Limit of Fine-Grained Soils

Plastic limit of fine-grained soils is conventionally determined in the laboratory by the soil thread rolling method. Many adverse comments have been recorded in the geotechnical engineering literature on the method about its reproducibility and operator dependency. The presen experimental study, which is based on a well-planned and meticulously executed experimental program, critically evaluates the effect of size of the rolled soil thread on the plastic limit of fine-grained soil and the operator dependency of the results. The results have shown that if the plastic limit tests are performed by a trained operator, then consistent results can be obtained and that the effect of size of the rolled soil thread on plastic limit is negligibly small.

A detailed study of Li-DNA fibres at various salt concentrations reveals a non-helical B-DNA and a possible similarity of solution and solid state structures

A thorough investigation of salt concentration dependence of lithium DNA fibres is made using X-ray diffraction. While for low salt the C-form pattern is obtained, crystalline B-type diffraction patterns result on increasing the salt concentration. The salt content in the gel (from which fibres are drawn) is estimated by equilibrium dialysis using the Donnan equilibrium principle. The salt range giving the best crystalline B pattern is determined. It is found that in this range meridional reflections occur on the fourth and sixth layer lines. In addition, the tenth layer meridian is absent at a particular salt concentration. These results strongly suggest the presence of non-helical features in the DNA molecule. Preliminary analysis of the diffraction patterns indicates a structural variability within the B-form itself. Further, the possibility of the structural parameters of DNA being similar in solid state and in solution is discussed.

EUF-analysis of tea soils of Southern India and tea productivity

The relationship between EUF extractable nutrients and conventional soil test extractable nutrients in the acid soils of Southern India on one hand and that between EUF values and tea productivity on the other are described. Close correlation exists between EUF-NO3–N at 20°C and CuSO4–Ag2SO4-extractable NO3–N (r=0.98***), EUF-Norg and Morgan's reagent extractable NH4–N (r=0.97***), total EUF-N and CuSO4–Ag2SO4-extractable NO3–N plus Morgan's reagent NH4–N (r=0.96***), EUF-P at 20°C and modified Bray II-P (r=0.93***) and EUF-P at 20°C plus that at 80°C and modified Bray II-P (r=0.91***). The EUF-K at 20°C shows close correlation with NH4OAc–K (r=0.80***), Ag-thiourea-K (r=0.86***) and Morgan's reagent-K (r=0.84***) whereas the EUF-K at 80°C shows close correlation with the difference in K contents of NH4OAc–K and Ag-thiourea-K (r=0.92***) or of NH4OAc–K and Morgan's reagent-K (r=0.93***) and fixed NH4–N (r=0.89***). EUF-Ca, EUF-Mg and EUF-Mn do not show any relationship with conventional soil test values. Tea productivity is strongly associated with EUF-N and EUF-P extracted at 20°C.

Dynamic Properties Of Soils From Insitu Tests - Discussion

Various field test (namely vibration tests on blocks or plates, steady-state vibration or Rayleigh wave tests, wave propagation tests, and cyclic load tests) were conducted at a number of sites in India to determine the dynamic shear modulus, G. Data obtained at different sites are described. The values of G obtained from the different tests at a given site vary widely. The rational approach for selecting the value of G from field tests for use in the analysis and design of soil-structure interaction problems under dynamic loads must account for the factors affecting G. The suggested approach, which provides a possible answer, is suitable in cohesionless soils below the water table where it is rather difficult, if not impossible, to obtain undisturbed samples.

Prediction of Compressibility of Overconsolidated Uncemented Soils

Overconsolidated soils exhibit a bilinear e-log p relationship. During virgin compression, microstructural units form larger stable groups, thereby reducing the operating specific surface and, in turn, net osmotic repulsive forces in the soil. The rebound portion of the e-log p curve is consequently flatter. The generalized relationship for compressibility of uncemented soils in the overconsolidated state has been developed in the form of e/eL = 1.122 = 0.188 log pc - 0.0463 log p in which e/eL is the generalized soil state parameter, pc is the preconsolidation pressure in kPa, p is the effective overburden pressure in kPa, e is the in situ void ratio, and eL is the void ratio corresponding to the liquid limit water content (wLG). This relationship can be usefully employed to predict both the preconsolidation pressure and compressibility responses of overconsolidated uncemented soils.

Amide-based Room Temperature Molten Salt as Solvent cum Stabilizer for Metallic Nanochains

A simple and efficient method for spontaneous organization of long assemblies of gold nanoparticles is described. This is achieved in a molten solvent containing acetamide, urea and ammonium nitrate that acts as a solvent cum stabilizer. There is no external aggregating agent or stabilizing agent added to the system. Depending on the concentration of the metal salt in the ternary melt, either chain-like assemblies or individual nanoparticles could be obtained. The amine groups present in the components of the melt (acetamide and urea) help in the stabilization of nanoparticles. Ammonium ions present in the eutectic mixture are likely to assist in the organization of the particles. The method is simple, highly reproducible and does not require any templating agent for the formation of chain-like assemblies.

Salt-Fog Pollution Test-A Modification to Suit Natural Conditions

Salt-fog tests as per International Electrotechnical Commission (IEC) recommendations were conducted on stationtype insulators with large leakage lengths. Later, tests were conducted to simulate natural conditions. From these tests, it was understood that the pollution flashover would occur because of nonuniform pollution layers causing nonuniform voltage distribution during a natural drying-up period. The leakage current during test conditions was very small and the evidence was that the leakage current did not play any significant role in causing flashovers. In the light of the experimental results, some modification of the test procedure is suggested.