927 resultados para Renaud, de Châtillon, prince of Antioch, d. 1187.


Relevância:

100.00% 100.00%

Publicador:

Resumo:

The conformations of Boc-l-Phe-(AiB)3-OH (1) and Boc-l-Phe-(Aib)3-OMe (2) which correspond to the amino terminal sequence of the emerimicins and antiamoebins have been studied in solution using 270 MHz 1H n.m.r. In dimethyl sulphoxide solution both peptides show the presence of two strongly solvent shielded Aib NH groups, consistent with a consecutive β-turn conformation, involving the Aib(3) and Aib(4) NH groups in intramolecular 4 → I hydrogen bonds. This folded conformation is maintained for 2 in chloroform solution. Nuclear Overhauser effect studies provide evidence for a Type II Phe-Aib β-turn. An X-ray diffraction study of Boc-(d,l)-Phe-(Aib)3-OH establishes a single type III(III′) β-turn conformation with Aib(2)-Aib(3) as the corner residues. A single intramolecular 4 → I hydrogen bond between Phe(I) CO and Aib(4) NH groups is observed in the crystal. The solution conformation may incorporate a consecutive type II-III′ structure for the Phe(1)-Aib(2)-Aib(3) segment, with the initial type II β-turn being destabilized by intermolecular interactions in the solid state.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

The ratio of the electron attachment coefficient eta to the gas pressure p (reduced to 0 degrees C) evaluated from the Townsend current growth curves in binary mixtures of electronegative gases (SF6, CCl2F2, CO2) and buffer gases (N2, Ar, air) clearly indicate that the eta /p ratios do not scale as the partial pressure of electronegative gas in the mixture. Extensive calculations carried out using data experimentally obtained have shown that the attachment coefficient of the mixture eta mix can be expressed as eta mix= eta (1-exp- beta F/(100-F)) where eta is the attachment coefficient of the 100% electronegative gas, F is the percentage of the electronegative gas in the mixture and beta is a constant. The results of this analysis explain to a high degree of accuracy the data obtained in various mixtures and are in very good agreement with the data deduced by Itoh and co-workers (1980) using the Boltzmann equation method.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

A finite element analysis of laminated shells reinforced with laminated stiffeners is described in this paper. A rectangular laminated anisotropic shallow thin shell finite element of 48 d.o.f. is used in conjunction with a laminated anisotropic curved beam and shell stiffening finite element having 16 d.o.f. Compatibility between the shell and the stiffener is maintained all along their junction line. Some problems of symmetrically stiffened isotropic plates and shells have been solved to evaluate the performance of the present method. Behaviour of an eccentrically stiffened laminated cantilever cylindrical shell has been predicted to show the ability of the present program. General shells amenable to rectangular meshes can also be solved in a similar manner.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

While the genetic control of wheat processing characteristics such as dough rheology is well understood, limited information is available concerning the genetic control of baking parameters, particularly sponge and dough (S&D) baking. In this study, a quantitative trait loci (QTL) analysis was performed using a population of doubled haploid lines derived from a cross between Australian cultivars Kukri x Janz grown at sites across different Australian wheat production zones (Queensland in 2001 and 2002 and Southern and Northern New South Wales in 2003) in order to examine the genetic control of protein content, protein expression, dough rheology and sponge and dough baking performance. The study highlighted the inconsistent genetic control of protein content across the test sites, with only two loci (3A and 7A) showing QTL at three of the five sites. Dough rheology QTL were highly consistent across the 5 sites, with major effects associated with the Glu-B1 and Glu-D1 loci. The Glu-D1 5 + 10 allele had consistent effects on S&D properties across sites; however, there was no evidence for a positive effect of the high dough strength Glu-B1-al allele at Glu-B1. A second locus on 5D had positive effects on S&D baking at three of five sites. This study demonstrated that dough rheology measurements were poor predictors of S&D quality. In the absence of robust predictive tests, high heritability values for S&D demonstrate that direct selection is the current best option for achieving genetic gain in this product category.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

The firing and delay characteristics of a simple coaxial type of triggered vacuum gap (TVG) are described and compared with the planar type. The designs are new and differ from those reported earlier. By analogy with gaseous breakdown the statistical and formative time lags have been determined.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

The dielectric measurement of ferroelectric trissarcosine calcium chloride (TSCC) was made under various pressures up to 6 kbar. A striking decrease in the peak value of the permittivity, epsilon r, at the transition temperature, Tc, was observed with increasing pressure. The value of Tc increases linearly with a pressure coefficient dTc/dp=11.1K kbar-1 at low pressures. This increase in Tc supports the suggestion that the ferroelectric transition is of the pure order-disorder type. It is suggested on the basis of the behaviour of epsilon r with pressure that the order of the ferroelectric transition changes from second to first order on application of pressure.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Interest in the development of aquaculture of the tropical spiny lobster, Panulirus ornatus, has increased markedly over the past 10 yr because of strong market demand and high prices. In Australia, economic conditions will necessitate that a semi-intensive approach be taken, possibly involving managed environmental conditions. Identification of optimal temperature and salinity levels will be necessary, and therefore two experiments were performed to examine these two parameters. Juvenile lobsters were grown in tanks at five temperatures (19, 22, 25, 28 and 31 C). Growth was significantly affected by temperature (P < 0.01), and maximal growth occurred at 25-31 C. Examination of the temperature effect on molt increment and intermolt period indicated that 27 C was the optimal temperature, at which molt increment was greatest and intermolt period the least. Temperature also had a significant (P < 0.01) positive effect on apparent feed intake (AFI). Juvenile lobsters were also exposed to four different salinities (20, 25, 30 and 35 ppt) over a period of 91 d. Significant differences (P < 0.01) were apparent for both survival and growth. Lowest survival occurred at 35 ppt which may be attributable to higher cannibalism at that salinity. Growth was highest at 35 ppt and progressively less at lower salinities. Although full marine salinity (35 ppt) will generate best performance of P. ornatus, its capacity to tolerate reduced salinity will provide greater opportunity to develop commercial aquaculture.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Antipyrine is a well known ligand for lanthanides (I). A forage through the organic literature of pyrazolones reveals that the 4-position of antipyrine is amenable to a wide variety of organic reactions. It should thus be possible to introduce suitable functional groups at this position and design new multidentate ligands for metal ions. It is also found that the coordination chemistry of lanthanides is much less well developed and far fewer ligands have been used for complexation with lanthanide ions compared to that of the d-transition metal ions. Keeping these points in view we have reported earlier, complexes of lanthanides with a bidentate ligand N,N-diethyl-antipyrine-4-carboxamide (2). In this communication we report the synthesis of two new ligands from Schiff base condensation of antipyraldehyde and the hydrazides of acetic and benzoic acids and the complexes formed by these hydrazones with lanthanide perchlorates.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Cinnamate is the product of phenylalanine ammonialyase (PAL). This compound, a precursor of phenolics in plants, has been shown to be phytotoxic. Cinnamate inhibits PAL activity in cucumber seedlings. DL-phenylalanine has the same effect on the enzyme but does not affect growth. Actinomycin D and cycloheximide are phytotoxic and inhibit PAL. Production of a double-peg has been noticed in the seedlings, grown in the presence of actinomycin D. Light stimulates PAL activity in the seedling.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Therese Molling (1890-1981) is in back row in white dress, to her left is her mother Henny Molling nee Meyerhof (1864-1934), her husband (and Therese's father) Adolf Molling (1865-1921) is posing on the grass in front.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Therese Molling (1890-1981) is in back row in white dress, to her left is her mother Henny Molling nee Meyerhof (1864-1934), her husband (and Therese's father) Adolf Molling (1865-1921) is posing on the grass in front.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Antipyrlne is a well known llgand for lanthanldes (i). A forage through the organic literature of pyrazolones reveals that the 4-position of antipyrlne is amenable to a wide variety of organic reactions. It should thus be possible to introduce suitable functional groups at this position and design new multidentate ligands for metal ions. It is also found that the coordination chemistry of lanthanides is much less well developed and far fewer ligands have been used for complexation with lanthanide ions compared to that of the d-transition metal ions.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Detailed ESR investigations of Mn2+ substituting for Ca2+ in Ca2Sr(C2H5COO)6 (DSP), Ca2Pb(C2H5COO)6 (DLP) and Ca2Ba(C2H5COO)6 (DBP), in single crystals and powders, over the temperature range from 200°C to -180°C have been carried out to study the successive phase transitions in these compounds. (DSP: [Tetragonal] ← 8.5°C → [tetragonal, ferroelectric] [tetragonal] ← -169°C → [monoclinic, ferroelectric]; DLP : [tetragonal] ← 60°C → [tetragonal, ferroelectric] ← -71.5°C → [monoclinic, ferroelectric]; [Cubic] ← -6°C → [orthorhombic] ← -75°C → [?]). Spectra have been analysed in terms of axial spin Hamiltonians and the temperature dependences of the parameters studied. In DSP and DLP across the I ↔ II transition, new physically and chemically inequivalent sites appear indicating the disappearance of the diad axes on which the propionate groups are located, bringing out the connection between the motional states of the propionate groups and the occurence of ferroelectricity. The II ↔ III transition also causes chemically inequivalent sites to develop, indicating that the transitions may not be isomorphous as believed previously. In DBP, the -6°C transition leads to (i) a doubling of both physically and chemically inequivalent sites (ii) a small (150 G at -6°C to 170 G at -8°C), but abrupt change in the magnitude of the zero-field splitting tensor D, and (iii) displacements of the orientations of the D tensors. Results are interpreted in terms of alternate rotations of the oxygen octahedra, showing participation of the carboxyl oxygens in the transition. No drastic changes in the parameters occur across the -75°C transition consistent with its second order nature. Similarities and dissimilarities of the ESR spectra of the three compounds in relation to the phase transitions, are discussed.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

The experimental results of delay time of a vacuum gap triggered by an exploding wire plasma have been reported. It consists of explosion delay time and propagation delay time. The explosion delay time has been found to be dependent on the parameters of the exploding wire and the exploding wire circuit and is independent of vacuum gap configuration. The propagation delay time depends on the properties of the exploding wire plasma and vacuum gap parameters such as the number of injection slots, gap spacing, gap polarity, etc. In the absence of prebreakdown current in the vacuum gap, the breakdown can be initiated only after the plasma completely bridges the gap spacing. Under this specific condition, it has been shown that the delay time data can be used to calculate the plasma velocity.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Handwritten pagination includes 508, 508a, 508b and then later skips from page 574 to page 577.