Only Changes (only + change)

Distribution by Scientific Domains


Selected Abstracts


Molecular and agronomic evaluation of wheat doubled haploid lines obtained through maize pollination and anther culture methods

PLANT BREEDING, Issue 4 2003
J. Guzy-Wrobelska
Abstract Although maize pollination (MP) and anther culture (AC) are alternative techniques widely used for wheat doubled haploid (DH) production, there is only limited information on the attributes of the plant materials produced through both methods. This study was conducted to evaluate genetic fidelity, transmission of parental gametes, and to compare field performance of DH populations produced by the MP and AC methods from the F1s of two crosses between spring bread wheat cultivars. The DH populations were compared to single seed descent (SSD) lines created from the same crosses. In total, 76 MP and 122 AC lines of the cross between cultivars of divergent origin were subjected to RAPD and AFLP analysis. Only changes in AFLP banding patterns, at similarly low frequencies, 0.18% (MP) and 0.21% (AC), were detected. The frequency of the DH lines affected by the variation, 14.5% (MP) and 14.8% (AC), was similar in both populations. For most of the DH lines, variation in 1-2 loci only, out of several hundreds scored, was observed. A total of 14.3% (MP) and 22.2% (AC) marker loci showed the significant segregation distortion from the expected 1 : 1 ratio, but in at least one polymorphic locus the within-cultivar variation was responsible for the skewed segregation. The field performance of the corresponding MP and AC lines derived from two crosses confirmed the equivalency of both DH populations. In most of the traits analyzed, the MP and AC lines performed the same as the SSD populations created from the same crosses. No, or very small differences in means and ranges, were observed when the best 10% of the lines from all three methods were compared. Moreover, the best 10 % of the lines of the cross between Polish wheat cultivars adapted to the local environment performed significantly better for some traits than different groups of checks used in the study. [source]


Theoretical study on the influence of ancillary ligand on the spectroscopic properties and electronic structures of phosphorescent Pt(II) complexes

INTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY, Issue 6 2010
Min Zhang
Abstract The geometries, energies, and electronic properties of a series of phosphorescent Pt(II) complexes including FPt, CFPt, COFPt, and NFPt have been characterized within density functional theory DFT calculations which can reproduce and rationalize experimental results. The properties of excited-states of the Pt(II) complexes were characterized by configuration interaction with singles (CIS) method. The ground- and excited-state geometries were optimized at the B3LYP/LANL2DZ and CIS/LANL2DZ levels, respectively. In addition, we also have performed a triplet UB3LYP optimization for complex FPt and compared it with CIS method in the emission properties. The datum (562.52 nm) of emission wavelength for complex FPt, which were computed based on the triplet UB3LYP optimization excited-state geometry, is not agreement with the experiment value (500 nm). The absorption and phosphorescence wavelengths were computed based on the optimized ground- and excited-state geometries, respectively, by the time-dependent density functional theory (TD-DFT) methods. The results revealed that the nature of the substituent at the phenylpyridine ligand can influence the distributions of HOMO and LUMO and their energies. Moreover, the auxiliary ligand pyridyltetrazole can make the molecular structure present a solid geometry. In addition, the charge transport quality has been estimated approximately by the predicted reorganization energy (,). Our result also indicates that the substitute groups and different auxiliary ligand not only change the nature of transition but also affect the rate and balance of charge transfer. By summarizing the results, we can conclude that the NFPt is good OLED materials with a solid geometry and a balanced charge transfer rate. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2010 [source]


Theoretical study on the spectroscopic properties and electronic structures of heteroleptic phosphorescent Ir(III) complexes

INTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY, Issue 6 2009
Min Zhang
Abstract The geometries, spectroscopic and electronic structures properties of a series of heteroleptic phosphorescent Ir(III) complexes including N981, N982, N983, N984 have been characterized by density functional theory calculations. The excited-state properties of the Ir(III) complexes have been characterized by CIS method. The ground- and excited-state geometries were optimized at the B3LYP/LANL2DZ and CIS/LANL2DZ levels, respectively. By using the time-dependent density functional theory method, the absorption and phosphorescence spectra were calculated based on the optimized ground- and excited-state geometries, respectively. The results show that the absorption and emission data agree well with the corresponding experimental results. The calculated results also revealed that the nature of the substituent at the 4-position of the pyridyl moiety can influence the distributions of HOMO and LUMO and their energies. In addition, the charge transport quality has been estimated approximately by the calculated reorganization energy (,). Our result also indicates that the positions of the substitute groups not only change the transition characters but also affect the charge transfer rate and balance, and complex N982 is a very good charge transfer material for green OLEDs. © 2008 Wiley Periodicals, Inc. Int J Quantum Chem, 2009 [source]


Multiphase approximation for small-angle scattering

JOURNAL OF APPLIED CRYSTALLOGRAPHY, Issue 1 2010
Dragomir Tatchev
The two-phase approximation in small-angle scattering is well known and is still the dominant approach to data analysis. The intensity scattered at small angles is proportional to the second power of the difference between the scattering densities of the two phases. Nevertheless, scattering contrast variation techniques are widely used, and they are obviously suitable for multiphase systems or systems with gradually varying scattering density, since if no parasitic scattering contributions are present the scattering contrast variation would only change a proportionality coefficient. It is shown here that the scattered intensity at small angles of a multiphase system can be represented as a sum of the scattering of two-phase systems and terms describing interference between all pairs of phases. Extracting two-phase scattering patterns from multiphase samples by contrast variation is possible. These two-phase patterns can be treated with the usual small-angle scattering formalism. The case of gradually varying scattering density is also discussed. [source]


Toxic effect of environmental acid-stress on the sperm of a hill-stream fish Devario aequipinnatus: A scanning electron microscopic evaluation

MICROSCOPY RESEARCH AND TECHNIQUE, Issue 2 2009
Sudip Dey
Abstract Environmental stress due to acidic pH of water was found to be one of the major factors leading to toxic effects on the sperm of a hill-stream fish Devario aequipinnatus of Meghalaya, India. The Scanning Electron Microscopy of the transverse section of testes of the fish collected from its natural habitat with acidic pH (5.6,6.0) showed that the sperms were clumped together and their tails were either absent or were of extremely small length. The acrosome and midpiece were also not well differentiated. When the fingerlings from the natural habitat were reared to maturity in aquarium with water from natural habitat after changing the pH to alkaline range (8.0,8.2), the clumping of the sperm was not observed. The sperm tail was found to be well-developed along with well-differentiated acrosome and midpiece. Since the only change in the water quality parameters of the experimental aquarium as compared to those of the natural habitat was the pH, it is evident that the abnormal features of the sperm observed in fish from natural habitat is mainly because of environmental acid stress. Microsc. Res. Tech., 2009. © 2008 Wiley-Liss, Inc. [source]


Rising incidence of post-transplant lymphoproliferative disease in kidney transplant recipients

BRITISH JOURNAL OF SURGERY (NOW INCLUDES EUROPEAN JOURNAL OF SURGERY), Issue 10 2001
Mr G. Libertiny
Background: The purpose of this study was to determine whether the incidence of post-transplant lymphoproliferative disease (PTLD) has been increasing in renal transplant recipients in this centre. Methods: Prospectively gathered data were analysed to establish trends in the epidemiology of PTLD in 1537 patients. Results: Overall, PTLD occurred in 2·3 per cent of renal transplant recipients. An increase in its incidence coincided with the introduction of cyclosporin in the 1980s. However, there was a further increase in the incidence of PTLD in the 1990s when the only change in immunosuppressive policy was the abandonment of pretransplantation blood transfusion. The latter increase was particularly pronounced in patients with early-onset PTLD in whom it presented within 600 days after transplantation. Conclusion: The incidence of PTLD has been increasing in renal transplant recipients. The recent increase appears to be independent of cyclosporin and may reflect the reduction in pretransplant blood transfusion. Changes in the incidence of PTLD may also mirror changes in the epidemiology of non-Hodgkin lymphoma in the general population. © 2001 British Journal of Surgery Society Ltd [source]


New visions of dental tissue research: Tooth development, chemistry, and structure

EVOLUTIONARY ANTHROPOLOGY, Issue 5 2008
Tanya M. Smith
Abstract Teeth are one of the best preserved and most commonly recovered elements in primate fossil assemblages. Taxonomic, functional, and phylogenetic hypotheses often rely on dental characters, despite considerable evidence of homoplasy in tooth form and large variation in tooth size within and among primates.1,2 Recent studies have led to new areas of research centered on incremental tooth development, chemical composition, and internal structure. Due to rapid technological developments in imaging and elemental sampling, these new approaches have the potential to increase our understanding of developmental biology, including not only changes in the pace of growth and reproduction, but also our assessments of diets, migration patterns, environments, and taxonomy. The integration of these temporal, chemical, and structural approaches heralds a bright future for the role of dental tissue research in evolutionary anthropology. © 2008 Wiley-Liss, Inc. [source]


Glaucomatous optic nerve injury involves early astrocyte reactivity and late oligodendrocyte loss

GLIA, Issue 7 2010
Janice L. Son
Abstract Glaucoma, a neurodegenerative disease affecting retinal ganglion cells (RGC), is a leading cause of blindness. Since gliosis is common in neurodegenerative disorders, it is important to describe the changes occurring in various glial populations in glaucoma animal models in relation to axon loss, as only changes that occur early are likely to be useful therapeutic targets. Here, we describe changes occurring in glia within the myelinated portion of the optic nerve (ON) in both DBA/2J mice and in a rat ocular hypertension model. In both glaucoma animal models, we found only a modest loss of oligodendrocytes that occurred after axons had already degenerated. In DBA/2J mice there was proliferation of oligodendrocyte precursor cells (OPCs) and new oligodendrocyte generation. Activation of microglia was detected only in highly degenerated DBA/2J ONs. In contrast, a large increase in astrocyte reactivity occurred early in both animal models. These results are consistent with astrocytes playing a prominent role in regulating axon loss in glaucoma. © 2010 Wiley-Liss, Inc. [source]


Preparing the HR profession for technology and information work

HUMAN RESOURCE MANAGEMENT, Issue 2-3 2004
Paul S. Hempel
Technology and human resource management have broad influences upon each other. Technology not only changes the administration of human resources (HR), which is the domain of e-HR, but also changes organizations and work. HR professionals must be able to adopt technologies that allow the reengineering of the HR function, be prepared to support organizational and work-design changes enabled by technology, and be able to support the proper managerial climate for innovative and knowledge-based organizations. An examination of HR professional degree programs shows that traditional HR education has poorly prepared the HR profession for these challenges. To address this shortfall, HR education must be revised to provide a greater focus on technological issues, and HR educators must acquire the skills needed to teach these courses. © 2004 Wiley Periodicals, Inc. [source]


SANISAND: Simple anisotropic sand plasticity model

INTERNATIONAL JOURNAL FOR NUMERICAL AND ANALYTICAL METHODS IN GEOMECHANICS, Issue 8 2008
Mahdi Taiebat
Abstract SANISAND is the name used for a family of simple anisotropic sand constitutive models developed over the past few years within the framework of critical state soil mechanics and bounding surface plasticity. The existing SANISAND models use a narrow open cone-type yield surface with apex at the origin obeying rotational hardening, which implies that only changes of the stress ratio can cause plastic deformations, while constant stress-ratio loading induces only elastic response. In order to circumvent this limitation, the present member of the SANISAND family introduces a modified eight-curve equation as the analytical description of a narrow but closed cone-type yield surface that obeys rotational and isotropic hardening. This modification enables the prediction of plastic strains during any type of constant stress-ratio loading, a feature lacking from the previous SANISAND models, without losing their well-established predictive capability for all other loading conditions including the cyclic. In the process the plausible assumption is made that the plastic strain rate decomposes in two parts, one due to the change of stress ratio and a second due to loading under constant stress ratio, with isotropic hardening depending on the volumetric component of the latter part only. The model formulation is presented firstly in the triaxial stress space and subsequently its multiaxial generalization is developed following systematically the steps of the triaxial one. A detailed calibration procedure for the model constants is presented, while successful simulation of both drained and undrained behavior of sands under constant and variable stress-ratio loadings at various densities and confining pressures is obtained by the model. Copyright © 2007 John Wiley & Sons, Ltd. [source]


Differential proteomic profiling to study the mechanism of cardiac pharmacological preconditioning by resveratrol

JOURNAL OF CELLULAR AND MOLECULAR MEDICINE, Issue 4 2006
Karel Bezstarosti
Abstract Recent studies demonstrated that resveratrol, a grape-derived polyphenolic phytoalexin, provides pharmacological preconditioning of the heart through a NO-dependent mechanism. To further explore the molecular mechanisms involved in resveratrol-mediated cardioprotection, we monitored the effects of resveratrol treatment after ischemia-reperfusion on the protein profile by implementation of proteomic analysis. Two groups of rats were studied; one group of animals was fed resveratrol for 7 days, while the other group was given vehicle only. The rats were sacrificed for the isolated working heart preparation and for isolation of cytoplasmic fraction from left ventricle homogenates to carry out the proteomic as well as immunoblot at baseline and at the end of 30 min ischemia/2-h perfusion. The results demonstrate significant cardiopro-tection with resveratrol evidenced by improved ventricular recovery and reduced infarct size and cardiomyocyte apopto-sis. The left ventricular cytoplasmic fractions were separated by two-dimensional electrophoresis (2-DE). Differentially regulated proteins were detected with quantitative computer analysis of the Coomassie blue stained 2-DE images and identified by MALDI-TOF (MS) and nanoLC-ESI-Q-TOF mass spectrometry (MS/MS). Five redox-regulated and precondi-tioning-related proteins were identified that were all upregulated by resveratrol: MAPKK, two different aB-crystallin species, HSP 27 and PE binding protein. Another HSP27 species and aldose reductase were downregulated and peroxire-doxin-2 remained constant. The results of the immunoblot analysis of phosphorylated MAPKK, -HSP27 and -aB-crys-tallin and PE binding protein were consistent with the proteomic findings, but not with peroxiredoxin-2. The proteomic analysis showed also downregulation of some proteins in the mitochondrial respiratory chain and matrix and the myofila-ment regulating protein MLC kinase-2. The results of the present study demonstrate that proteomic profiling enables the identification of resveratrol induced preconditioning-associated proteins which reflects not only changes in their expression level but also isoforms, post-translational modifications and regulating binding or activating partner proteins. [source]


Applying a ,stages of change' model to enhance a traditional evaluation of a research transfer course

JOURNAL OF EVALUATION IN CLINICAL PRACTICE, Issue 4 2003
Leslie L. Buckley MD MPH
Abstract The aim of this study was to utilize an evaluation tool based on Prochaska's model of change in order to assess behaviour change as part of an evaluation process for a research transfer training programme (RTTP). The RTTP was a training programme offered to scientists in a psychiatry department and research institute to gain skills in research transfer. In addition to a traditional course evaluation framework evaluating overall satisfaction with the course and whether or not learning objectives were met, an additional ,stages of change' evaluation tool designed to assess change along a continuum was utilized. This instrument measured change in participants' attitudes, intentions and actions with respect to research transfer practice and consisted of a 12-question survey completed by participants prior to taking the course and 3 months post-course. In two out of the three categories, attitudes and intention to practice, there was positive change from pre- to post-course (P < 0.05). Although there was a trend of increased RT-related action, this was less robust and did not reach significance. For the RTTP transfer course, a ,stages of change' model of evaluation provided an enhanced understanding by showing changes in participants that would otherwise have been overlooked if only changes in RT behaviour were measured. Additionally, evaluating along a change continuum specifically identifies areas for improvement in future courses. The instrument developed for this study could also be used as a pre-course, participant needs assessment to tailor a course to the change needs of participants. Finally, this ,stages of change' approach provides insight into where barriers to change may exist for research transfer action. [source]


Volatile and Nonvolatile Amines in Mediterranean Hake as Function of their Storage Temperature

JOURNAL OF FOOD SCIENCE, Issue 1 2001
S. Baixas-Nogueras
ABSTRACT: The main amines in frozen and fresh hake (Merluccius merluccius) are the natural polyamines, spermidine. The levels of volatile and nonvolatile amines during storage of hake were strogly dependent on temperature. In samples stored at -20° only changes in dimethylamine and agmatine were found, whereas major changes were observed in samples stored at higher temperatures. Cadaverine was the major amine formed followed by histamine, putrescine and tyramine. The maximum levels of biogenic amines were lower than those reported for other fish species. Trimethylamine and biogenic amines related to hake spollage showed levels higher in fresh than in frozen samples, whereas levels of natural polyamines were not statistically different. [source]


Urban paediatric trauma due to stab wounds: an Israeli hospital experience

ACTA PAEDIATRICA, Issue 7 2009
Ibrahim Abu-Kishk
Abstract Objective:, To assess the incidence and types of stab wounds to hospitalized children and adolescents. Subjects:, The sample consisted of patients, age 6,18 years, who were admitted to our hospital with sustained injury between 1991 and 2007. Results:, In total, 83 patients were admitted as a result of penetrating (n = 51) and superficial (n = 32) injuries. Eighty-two were hospitalized, and one was declared dead upon arrival. Only 11 patients were hospitalized during the 1991,2000 period, and 71 during the 2001,2007 period. Ten patients were admitted to the intensive care unit (ICU); 23 patients were operated (hospital mortality = 0). Evacuation time (time from injury to hospital) was 10 min (mean time; maximum 35 min). Conclusion:, This study found higher rates of hospitalization compared with those over a decade ago. These rates reflect not only changes in hospitalization trends and/or population growth in the hospital area but also an increase of urban violence. Israeli hospitalization system deals with paediatric trauma effectively, being well trained because of permanent terrorist activity. [source]