bluuebunny/crossref_metadata_2025_split huggingface dataset:
Elastic, Piezoelectric and Dielectric Constants of Pentaerythritol
Authors: Ramamoorthy P. , Krishnamurthy N. 
Published: January 2007

AbstractThe elastic, piezoelectric and dielectric constants of pentaerythritol, C(CH2OH)4, have been computed employing the method of long waves and the unscreened rigid ion potential model developed by RAMAMOORTHY and KRISHNAMURTHY. Piezoelectric contribution is taken into account in the computation of elastic constants. This is the first report on the piezoelectric and dielectric constants of pentaerythritol. In the notations followed by LANDOLT‐BORNSTEIN the computed piezoelectric constants are: g14 = 4.82, g15 = 4.37, g31 = 16.21 and g36 = 5.89 (in unit of 10−1Vm/N) and the static dielectric constants are: K1 = 2.38 and K3 = 2.47. The hydrogen bonding in pentaerythritol has no effect on its dielectric behaviour. Calculation of acoustic velocities in piezoelectric crystals and as a special case to the crystals of class 4 is explained in detail. Sound velocities calculated from the elastic, piezoelectric and dielectric constants computed in the present investigation agree with the experimental values determined by the ultrasonic method.
Crystal Structure of Fibrillar Sodium Trimolybdate Hydrate by Powder Diffraction Method
Authors: Łasocha W. , Rafalska‐Łasocha A. , Schenk H. 
Published: January 2007

AbstractThe crystal structure of polycrystalline fibrillar sodium trimolybdate Na2Mo3O10. 3 H2O, has been solved ab initio by Powder Diffraction – Direct Methods package POWSIM. The structure was refined by the Rietveld method with final discrepancy factors RF = 6.9 and Rwp = 17.1%. The structure consists of polymeric chains of Mo‐O polyhedra parallel to the b axis. The space group is C2/m (12), a = 17.179(1), b = 3.7757(3), c = 10.8571(8) Å, β = 115.417(6)°, V = 636.06(6) Å3, Z = 2.
The influence of tartaric acid on the growth kinetics of silver single crystals
Authors: Rashkov R. , Daskalova A. , Nanev Chr. N. 
Published: January 2007

AbstractThe influence of tartaric acid (TA) on both the growth kinetics and morphology of silver single crystals was investigated in situ during electrocrystallization. Using laser interferometry the dependence of the monoatomic step velocity vs. overvoltage at different concentrations of TA was studied. Measuring the normal growth rate R we calculated the current on the front crystal face. It is shown that the addition of TA changes its value in complicated way vs. overvoltage.
Activity of nonparallel center of growth of (001) face of TGS single crystal under inconstant conditions of crystallization
Authors: Bikov A. Z. , Stoichkov S. D. 
Published: January 2007

AbstractMorphologic and kinetic behaviour of the hill of the (001) face of TGS crystal, generated by unparallel dislocation center of growth under inconstant supersaturation and temperature has been experimentally examined. Some irreversible changes in the shape of the hill top, as a hysteresis in its normal rate of growth is registered. A model, on the base of which a qualitative anylsis of the phenomenon is proposed.
Growth of P‐Chloroacetanilide Crystals by Gel Aided Solution Technique and Their Characterisation
Authors: Babu K. Rajendra , Deepa M. , Vaidyan V. K. , Nair C. M. K. 
Published: January 2007

AbstractSingle crystals of P‐chloroacetanilide which exhibit non‐linear optical properties have been grown by solution‐gel technique for the first time. Studies on the crystal nucleation have been carried out. The grown crystals are characterised by IR, XRD, and optical microscopy.
Influence of the Fe+2 Ions on the Dissolution Rate of Potassium Chloride
Authors: Omar W. , Ulrich J. 
Published: January 2007

AbstractA fluidized bed crystallizer is employed to investigate dissolution rates of potassium chloride in the presence of Fe+2 ions at 30 °C. With increasing concentrations of Fe+2 ions, an initial decrease of the dissolution rates in the range between 0 and 10 ppm is followed by a gradual increase in the range between 10 and 50 ppm. The addition of Fe+2 changes the pH level of the solution to a strongly acidic level and increases the streaming potential of the suspension. The acceleration of the dissolution rate is attributed to the adsorption of protons which increase the charge density of the particle and hence the thickness of the diffusion layer will consequently be decreased.
Growth and Optical Properties of LiNbO3: MgO Single Crystals
Authors: Sugak D. Yu. , Matkovskii A. O. , Solskii I. M. , Kopko B. M. , Ya. Oliinyk V. , Stefanskii I. V. , Gaba V. M. , Grabovskii V. V. , Zaritskii I. M. , Rakitina L. G. 
Published: January 2007

AbstractThe technological procedure of the manufacturing of the LiNbO3˙ single crystals doped with 5 mol.% MgO is described in this paper. The results of the investigation of the crystal optical properties, ESR spectra and optical homogeneity are presented. The refractive index dispersion in 300–700 nm region and their temperature dependencies in 20–500 °C range are measured. The dispersion curve is approximated by the two oscillator Sellmeier formula. The data on the LiNbO3: MgO crystal optical resistance are presented.
Electrical and Photoelectrical Properties of n‐CuInS2 Single Crystals
Authors: Cybulski D. , Opanowicz A. 
Published: January 2007

AbstractThe temperature dependences of free electron density and mobility in n‐CuInS2 single crystals have been determined from the Hall effect measurements. The ionization energy of donors and their densities have been estimated. The results of measurements show that the crystals are strongly compensated. The spectral distribution of photoconductivity, the dependence of photoconductivity on excitation intensity, and the photoconductivity decay with time have been measured in the n‐CuInS2 crystals at different temperatures. The results of photo‐conductivity measurements suggest linear recombination of photo‐electrons at weak excitation and quadratic recombination at high excitation intensity. The compensated deep acceptor probably acts as the recombination centre.
4‐(2‐Methylphenyl)‐1,2,3,4,5,6,7,8‐octahydroquinazoline‐2,5‐dione (I) and 4‐(4chlorophenyl)‐1,2,3,4,5,6,7,8‐octahydroquinazoline‐2,5‐dione (II)
Authors: Kendi E. , Saraç S. , Yarim M. , Ertan M. , Läge M. , Krebs B. 
Published: January 2007

AbstractThe crystal and molecular structures of the title compounds have been determined by x‐ray structure analysis. The compounds (I) and (II) crystallize in space groups P212121 and 12/a respectively. The structures were solved by direct methods and refined to R = 0.058 and R = 0.046. The saturated pyrimidine‐2‐one ring in both structures deviates from the planarity. There are two intermolecular hydrogen bonds in (I) and (II).The configuration at C4 in (I) is S.
The Activity of Substrates in the Catalyzed Nucleation of Undercooled Melts and Aqueous Aerosols
Authors: Gutzow I. , Vassilev Ts. , Dobreva A. , Todorova S. 
Published: January 2007

AbstractThe aim of the present contribution is to analyze and to correlate the experimental evidence on the catalyzed nucleation in the crystallization of undercooled melts. This is done by using a new, generalized theoretical approach accounting for both the thermodynamics of adhesion (i.e. the interface bonding) and for correcting structural factors. Beside the usually considered lattice discrepancy substrate/overgrowing crystal in the present contribution as an additional structural corrective is introduced the polarizability of the building units of both interface constituents. It is shown that such a combined approach gives for the first time a way to correlate quantitatively experiment and theory in the case both of heterogeneous meteorolgical important nucleation catalysis and in the crystallization of glassforming organic and inorganic polymer melts. This approach leads to the possibility of predicting further promising nucleation catalysts and especially appropriate substrates in the induced crystallization of ice from undercooled water.An additional advantage of the theoretical concept derived here is that it allows also the determination of nucleation activity, Φ, of amorphous substrates or of crystallization cores with distorted structure – i.e. in cases, where the lattice discrepancy approach is impossible from the very beginning.Two main sources of experimental data are used: crystallization of aqueous aerosols induced by various crystallization cores and the heterogeneous crystallization of undercooled glassforming melts.Thus a new solution of a classical problem is attempted which may be of use in both meteorology and in the technical applications of induced nucleation by using foreign substrates.
Directional Solidification of Faceting Material in a Centrifuge
Authors: Inatomi Y. , Kitajima O. , Huang W. , Kuribayashi K. , Sawada Y. 
Published: January 2007

AbstractIn situ observation of directional solidification of salol was carried out at a centrifuge acceleration of 10 G (G = 9.81 m/s2). Growth rate, temperature distribution and flow pattern in front of the solid‐liquid interface could be simultaneously measured and visualized using a microscopic interferometer and thermocouples. The specimens were transparent, faceting organic compounds, which develop cellular arrays. These materials of commercial grade were purified by several zone‐refining cycles on a laboratory scale and were enclosed in quartz glass cells. The solidification were controlled by the imposed temperature gradient in the cell and cooling rate at the both side of the cell. The growth direction was adjusted to opposite to the acceleration vector. We found appearance of a local recalescence region in front of the growing surface not only under 1 G but 10 G. The uniformity of the recalescence region along the interface seemed to be defined by the flow induced by the centrifuge acceleration. We considered the non‐uniform temperature distribution ahead of the interface as one of the driving forces of the interface breakdown.
The Oscillations of Crystal Growth Rates at their Formation in the Regime of free Convection of a Solution; Statistical Investigation
Authors: Treivus E. B. 
Published: January 2007

AbstractThe growth rate oscillations of {101) NaNO3 crystal face have been measured at certain range of supersaturation of a water solution. It has been found, that root‐mean‐square amplitude of the oscillations of rates increases linearly with the growth of the mean growth rate. The supposition has been made that observed oscillations belong to flicker noise.
Crystallization of Silver‐Germanium Alloys under Microgravity I. Eutectic Crystallization in Hypoeutectic Alloy
Authors: Vojtěch D. , Holeček S. , Barta C. , Barta C. , Görler G. P. , Otto G. , Wittmann K. 
Published: January 2007

AbstractThe results of a study on eutectic crystallisation in the hypoeutectic alloy under different convection conditions are presented. Buoyancy driven convection was suppressed by processing the samples under microgravity conditions. The effect of convection level on the eutectic crystallisation is shown to be significant: In the absence of convection, the non‐equilibrium level of the process is enhanced. The characteristic dependence of the particle size on the distance from the surface of a sample, observed on the minor phase of the eutectic, is discussed.
Alignment Properties of Some Polymeric Layers
Authors: Frunza S. , Frunza L. , Moldovan R. , Stoenescu D. N. , Grigoriu G. , Luca C. , Grigoriu A. 
Published: January 2007

AbstractOrientational properties of rubbed thin polymer layers with vinylic backbone and different side groups are presented. Some of these polymers lead to the alignment of LC molecules parallel to the rubbing direction whereas other polymers impose a perpendicular orientation. The stability of the obtained alignment as function of the temperature was tested.
Crystal Growth of Boron Sillenite Bi24B2O39
Authors: Burianek M. , Mühlberg M. 
Published: January 2007

AbstractThe Sillenite type Bi24B2O39 is an incongruently melting compound at Tp = 650 °C. Single crystals have been grown from non‐stoichiometric melts as well as from high temperature solutions by the Czochralski method and by a top seeded solution growth technique (TSSG), respectively.The main difficulty in the crystal growth of Bi24B2O39 arises from the very small field of crystallization in the binary system Bi2O3–B2O3. Further problems are caused by the nearly simultaneous formation of the 2:1 compound Bi4B2O9 and the 12:1 compound Bi24B2O39. Therefore, a precise thermal reinvestigation of the phase diagram was carried out using DTA‐technique on the Bi2O3‐rich side. Additionally, crystal growth runs have been started in the ternary system Bi2O3–B2O3–Li2O in order to extend the crystallization field. Homogeneous melts were more difficult to prepare because of the high density difference between Bi2O3 (∂ = 9.3 g/cm3) and B2O3 (∂ = 2.46 g/cm3). The homogeneity of the melts were improved, using Bi2O3 and synthesized Bi4B2O9 (∂ = 8.25 g/cm3) as starting materials. As a result of this procedure, small crystals of Bi24B2O39 were grown from these starting materials and the lattice parameter were determined.
Glucose and Fructose Adsorption on Sucrose Crystals. Their Role as Habit‐Modifiers
Authors: Sgualdino G. , Vaccari G. , Mantovani G. , Aquilano D. 
Published: January 2007

AbstractExperimental evidences show that α‐D‐glucose and β‐D‐fructose work as habit‐modifiers of sucrose crystals grown from aqueous solutions at high concentration only. Their ability to affect the sucrose habit is examined from structural point of view, through stereochemical analysis of both additive molecules and surface sites on some significant polar and non‐polar forms of sucrose crystal. We referred to the classical TLK (terraces, ledges, kinks) model and restricted the adsorption interactions to the H‐bondings only. Notwithstanding the simple qualitative model we adopted, our method of analysis appears satisfactory to interpret analogies and differences in selectivity between glucose and fructose. However, it is not able to explain why the additive concentrations, needed to induce macroscopic effects. are so high. To clear this aspect, we assumed a behaviour as “disruption tailor‐made additives” for both monosaccharides. Finally, sucrose crystals grown in the presence of equimolecular mixture of glucose and fructose (50 + 50 g/100 g H2O), examined by X‐ray powder diffractometry, show the systematic splitting of main diffraction peaks; the systematic effect reveals the influence of both impurities on the bulk structure of sucrose crystal.
Zn–Mg–(Y, RE) Quasicrystals: Growth Experiments and Phase Diagrams
Authors: Langsdorf A. , Seuring C. , Hitter F. , Assmus W. 
Published: January 2007

AbstractWe report about our work on the preparation and characterization of icosahedral Zn–Mg–(Y, RE) (RE = rare earth element) quasicrystals. We obtained single grains of the icosahedral (i‐) phase via slow cooling experiments and with the Bridgman technique. We revealed a composition range of the i‐phase, within which the structure changes. Additionally a systematic investigation of the Zn–Mg–Y phase diagram, including the determination of the primary solidification area of the icosahedral phase is presented. It was found that for a growth from the melt a starting composition with a low Y‐content is needed.
Growth of CeCu2Si2 from a Levitating Melt using the Nacken Kyropoulos Technique
Authors: Nüttgens S. , Büllesfeld F. , Reutzel S. , Finsterbusch D. , Assmus W. 
Published: January 2007

AbstractLarge CeCu2Si2 single crystals of several mm3. are grown by the Nacken Kyropoulos technique. The crystals show interesting low temperature properties which strongly depend on the stoichiometry.
Top‐Seeded Solution Growth of Monomethylurea Single Crystals
Authors: Zha M. , Ardoino M. , Zanotti L. , Paorici C. , Sora I. Natali 
Published: January 2007

AbstractIt was previously reported on the growth of monomethylurea (NMU) single crystals from methanol solution by a mechanical limitation‐direction (MLD) technique in which long (100) oriented seeds, capped on their extremities, were employed. The crystals obtained by this technique, in spite of their good structural and optical quality, presented their core region, in which the seed was located, with a higher density of structural defects and henceforth a reduced cross section useful for optical applications. It is here referred to a new, top‐seeded growth configuration, devised on the basis of a preliminary PBC analysis for assessing the morphological importance of the crystal faces experimentally observed during crystal growth, which allows to grow NMU crystals in which the defected core region is removed for almost the entire length of the crystal.
Auxin Biosynthesis by the YUCCA Genes in Rice
Authors: Yamamoto Yuko , Kamiya Noriko , Morinaka Yoichi , Matsuoka Makoto , Sazuka Takashi 
Published: January 2007

Abstract
Although indole-3-acetic acid (IAA), the predominant auxin in plants, plays a critical role in various plant growth and developmental processes, its biosynthesis and regulation have not been clearly elucidated. To investigate the molecular mechanisms of IAA synthesis in rice (Oryza sativa), we identified seven YUCCA-like genes (named OsYUCCA1-7) in the rice genome. Plants overexpressing OsYUCCA1 exhibited increased IAA levels and characteristic auxin overproduction phenotypes, whereas plants expressing antisense OsYUCCA1 cDNA displayed defects that are similar to those of rice auxin-insensitive mutants. OsYUCCA1 was expressed in almost all of the organs tested, but its expression was restricted to discrete areas, including the tips of leaves, roots, and vascular tissues, where it overlapped with expression of a β-glucuronidase reporter gene controlled by the auxin-responsive DR5 promoter. These observations are consistent with an important role for the rice enzyme OsYUCCA1 in IAA biosynthesis via the tryptophan-dependent pathway.
Chlamydomonas reinhardtiiHas Multiple Prolyl 4-Hydroxylases, One of Which Is Essential for Proper Cell Wall Assembly
Authors: Keskiaho Katriina , Hieta Reija , Sormunen Raija , Myllyharju Johanna 
Published: January 2007

AbstractProlyl 4-hydroxylases (P4Hs) catalyze formation of 4-hydroxyproline (4Hyp), which is found in many plant glycoproteins. We cloned and characterized Cr-P4H-1, one of 10 P4H-like Chlamydomonas reinhardtii polypeptides. Recombinant Cr-P4H-1 is a soluble 29-kD monomer that effectively hydroxylated in vitro both poly(l-Pro) and synthetic peptides representing Pro-rich motifs found in the Chlamydomonas cell wall Hyp-rich glycoprotein (HRGP) GP1. Similar Pro-rich repeats that are likely to be Cr-P4H-1 substrates are also present in the cell wall HRGP GP2 and probably GP3. Suppression of the gene encoding Cr-P4H-1 by RNA interference led to a defective cell wall consisting of a loose network of fibrils resembling the inner and outer W1 and W7 layers of the wild-type wall, while the layers forming the dense central triplet were absent. The lack of Cr-P4H-1 most probably affected 4Hyp content of the major HRPGs of the central triplet, GP1, GP2, and GP3. The reduced 4Hyp levels in these HRGPs can also be expected to affect their glycosylation and, thus, the interactive properties and stabilities of their fibrous shafts. Interestingly, our RNA interference data indicate that the nine other Chlamydomonas P4H-like polypeptides could not fully compensate for the lack of Cr-P4H-1 activity and are therefore likely to have different substrate specificities and functions.
Cellular immune response, stress resistance and competitiveness in nestling great tits in relation to maternally transmitted carotenoids
Authors: BERTHOULY ANNE , HELFENSTEIN FABRICE , RICHNER HEINZ 
Published: January 2007

Summary

Egg yolks contain carotenoids that protect biological molecules against free‐radical damage and promote maturation of the immune system. Availability of carotenoids to birds is often limited. Trade‐offs can thus arise in the allocation of carotenoids to different physiological functions, and mothers may influence the immunocompetence of nestlings by modulating the transfer of carotenoid to the yolk.
In the great tit Parus major, we experimentally manipulated the dietary supply of carotenoid to mothers, and partially cross‐fostered hatchlings to investigate the effect of an increased availability of carotenoids during egg laying on immunocompetence of nestlings.
In addition, we infested half of the nests with hen fleas Ceratophyllus gallinae to investigate the relationship between carotenoid availability, resistance to ectoparasites and immunocompetence.
We found that the procedure of cross‐fostering can reduce the immune response of nestlings, but this effect can be compensated by the maternally transferred carotenoids. Cross‐fostered nestlings of carotenoid‐supplemented females show a similar immune response to non‐cross‐fostered nestlings, while cross‐fostered nestlings of control females mounted a weaker cell‐mediated immune response. This suggests that yolk carotenoids may help nestlings to cope with stress, for example the one generated by cross‐fostering and/or they may enhance nestling competitiveness.
There was no statistically significant interaction between parasite and carotenoid treatments, as would be expected if carotenoids helped nestlings to fight parasites. Under parasite pressure, however, lighter nestlings raised a lower immune response, while the immune response was only weakly correlated with body mass in uninfested nests.
The functional significance of residual yolk in hatchling lizards Amphibolurus muricatus (Agamidae)
Authors: RADDER R. S. , WARNER D. A. , CUERVO J. J. , SHINE R. 
Published: January 2007

Summary

Although post‐hatching parental care is uncommon in reptiles, reproducing females may none the less contribute to the nutritional state of their offspring by depositing more yolk into the egg than is needed for embryogenesis. This ‘extra’ yolk (i.e. residual yolk) is drawn into the offspring's body prior to hatching and is widely assumed to serve as an energy resource for early life activities. However, empirical data on the functional significance of residual yolk are rare.
We surgically removed residual yolk from hatchling lizards Amphibolurus muricatus to evaluate its effects on offspring growth and survival over 4 weeks under two environmental conditions: low or high food abundance.
Unsurprisingly, higher food abundance enhanced growth rates of the young lizards. However, experimental removal of residual yolk did not affect any of the traits that we measured in either nutritionally harsh or benign post‐hatching environments.
Overall, our results challenge the common assumption that residual yolk is an important source of energy during early life in lizards, and suggest instead that residual yolk is of trivial nutritional significance (especially, relative to prey availability). Residual yolk in A. muricutus may instead have a different (non‐nutritive) function, or be a nonfunctional relict retained through phylogenetic conservatism from ancestral taxa.