Search

Purpose To investigate parametric changes in the apparent diffusion coefficient (ADC) at multiple timepoints during and after completion of primary proton and carbon ion irradiation of prostate cancer (PCa) as compared with normal-appearing prostate parenchyma. Materials and Methods In all, 92 patients with histologically confirmed PCa received either proton or carbon ion hypofractionated radiotherapy (RT). All were prospectively evaluated with diffusion-weighted magnetic resonance imaging (DWI-MRI) at five timepoints: baseline, day 10 during therapy and 6 weeks, 6 months, and 18 months after treatment. Linear mixed models (LMM) were used to evaluate the effects of radiation, antihormonal therapy, time, and type of particle irradiation on manual ADC measurements. ADC differences related to prostate-specific antigen (PSA) relapse according to PSA thresholds and to Vancouver rules and Phoenix criteria were examined using LMM and unpaired Student's t-test. Results A measurable and continuous increase of tumor ADC measurements from baseline (1.194 × 10−3 mm2/s) during (1.350 × 10−3 mm2/s, day 10, P = 0.006) and after treatment (1.355/1.430/1.490 × 10−3 mm2/s, week 6 / month 6 / month 18, P = 0.001/

Identifying mechanisms through which individual differences in reward learning emerge offers an opportunity to understand both a fundamental form of adaptive responding as well as etiological pathways through which aberrant reward learning may contribute to maladaptive behaviors and psychopathology. One candidate mechanism through which individual differences in reward learning may emerge is variability in dopaminergic reinforcement signaling. A common functional polymorphism within the catechol-O-methyl transferase gene (COMT; rs4680, Val158Met) has been linked to reward learning, where homozygosity for the Met allele (linked to heightened prefrontal dopamine function and decreased dopamine synthesis in the midbrain) has been associated with relatively increased reward learning. Here, we used a probabilistic reward learning task to asses response bias, a behavioral form of reward learning, across three separate samples that were combined for analyses (age: 21.80 ± 3.95; n = 392; 268 female; European-American: n = 208). We replicate prior reports that COMT rs4680 Met allele homozygosity is associated with increased reward learning in European-American participants (β = 0.20, t = 2.75, P < 0.01; ΔR2 = 0.04). Moreover, a meta-analysis of 4 studies, including the current one, confirmed the association between COMT rs4680 genotype and reward learning (95% CI −0.11 to −0.03; z = 3.2; P < 0.01). These results suggest that variability in dopamine signaling associated with COMT rs4680 influences individual differences in reward which may potentially contribute to psychopathology characterized by reward dysfunction.

Maternal genetic effects (MGEs), where genes expressed by mothers affect the phenotype of their offspring, are important sources of phenotypic diversity in a myriad of organisms. We use a single-locus model to examine how MGEs contribute patterns of heritable and nonheritable variation and influence evolutionary dynamics in randomly mating and inbreeding populations. We elucidate the influence of MGEs by examining the offspring genotype-phenotype relationship, which determines how MGEs affect evolutionary dynamics in response to selection on offspring phenotypes. This approach reveals important results that are not apparent from classic quantitative genetic treatments of MGEs. We show that additive and dominance MGEs make different contributions to evolutionary dynamics and patterns of variation, which are differentially affected by inbreeding. Dominance MGEs make the offspring genotype-phenotype relationship frequency dependent, resulting in the appearance of negative frequency-dependent selection, while additive MGEs contribute a component of parent-of-origin dependent variation. Inbreeding amplifies the contribution of MGEs to the additive genetic variance and, therefore enhances their evolutionary response. Considering evolutionary dynamics of allele frequency change on an adaptive landscape, we show that this landscape differs from the mean fitness surface, and therefore, under some condition, fitness peaks can exist but not be "available" to the evolving population.

We evaluated the performance of Time to Clinical Stability (TCS), a longitudinal outcome measure using four physiologic parameters (temperature, heart rate, respiratory rate, and use of supplemental oxygen), among children enrolled in a prospective study of pneumonia hospitalizations. We calculated the time from admission to normalization for each of the four parameters individually and various combinations of these parameters (>2 parameters). We assessed for agreement between the combined TCS measures and both hospital length of stay and an ordinal severity scale (non-severe, severe, and very severe). Overall, 323 (96.7%) of 334 included children had ≥1 parameter abnormal on admission; 70 (21%) children had ≥1 parameter abnormal at discharge. For the four combined measures, median TCS decreased with increasing age. Increasing TCS was associated with both longer length of stay and increasing disease severity. The simplest combined measure incorporating only respiratory rate and need for supplemental oxygen performed similarly to more complex measures including additional parameters. Our study demonstrates that longitudinal TCS measures may be useful in children with pneumonia, both in clinical settings to assess recovery and readiness for discharge, and as an outcome measure in research and quality assessments. Additional study is needed to further validate our findings.

We report on a detailed comparison of the thermodynamic properties of the heavy-fermion system CeCu6 which can be described as a Fermi liquid at low temperatures T < 0.1 K, and CeCu5.9Au0.1 where strong deviations from the Fermi-liquid behaviour were found previously in the T dependence of the specific heat C, magnetization M and electrical resistivity p. The specific heat, magnetization and elastic constants are investigated in a large range of magnetic fields, corroborating the idea that the non-Fermi-liquid behaviour arises from low-lying spin excitations. For the elastic constants, a striking linear T dependence is found for CeCu5.9Au0.1 in contrast to the T2 Fermi-liquid behaviour of CeCu6.

Stomatopod crustaceans have the most complex assemblage of visual receptor classes known; retinas of many species are thought to express up to 16 different visual pigments. Physiological studies indicate that stomatopods contain up to six distinct middle-wavelength-sensitive (MWS) photoreceptor classes, suggesting that no more than six different MWS opsin gene copies exist per species. However, we previously reported the unexpected expression of 6-15 different MWS genes in retinas of each of five stomatopod species (Visual Neurosci 26: 255-266, 2009). Here, we present a review of the results reported in this publication, plus new results that shed light on the origins of the diverse colour and polarization visual capabilities of stomatopod crustaceans. Using in situ hybridization of opsins in photoreceptor cells, we obtained new results that support the hypothesis of an ancient functional division separating spatial and polarizational vision from colour vision in the stomatopods. Since evolutionary trace analysis indicates that stomatopod MWS opsins have diverged both with respect to spectral tuning and to cytoplasmic interactions, we have now further analyzed these data in an attempt to uncover the origins, diversity and potential specializations among clades for specific visual functions. The presence of many clusters of highly similar transcripts suggests exuberant opsin gene duplication has occurred in the stomatopods, together with more conservative, ancient gene duplication events within the stem crustacean lineage. Phylogenetic analysis of opsin relatedness suggests that opsins specialized for colour vision have diverged from those devoted to polarization vision, and possibly motion and spatial vision.

When individuals interact, phenotypic variation can be partitioned into direct genetic effects (DGEs) of the individuals' own genotypes, indirect genetic effects (IGEs) of their social partners' genotypes and epistatic interactions between the genotypes of interacting individuals ('genotype-by-genotype (GxG) epistasis'). These components can all play important roles in evolutionary processes, but few empirical studies have examined their importance. The social amoeba Dictyostelium discoideum provides an ideal system to measure these effects during social interactions and development. When starved, free-living amoebae aggregate and differentiate into a multicellular fruiting body with a dead stalk that holds aloft viable spores. By measuring interactions among a set of natural strains, we quantify DGEs, IGEs and GxG epistasis affecting spore formation. We find that DGEs explain most of the phenotypic variance (57.6%) whereas IGEs explain a smaller (13.3%) but highly significant component. Interestingly, GxG epistasis explains nearly a quarter of the variance (23.0%), highlighting the complex nature of genotype interactions. These results demonstrate the large impact that social interactions can have on development and suggest that social effects should play an important role in developmental evolution in this system.

A battery of cognitive ability, knowledge, and non-ability measures were administered to 105 college students enrolled in a cooperative school-work program and used to predict academic and job performance. Composite scores for each domain were derived from factor analyses of 11 measures of verbal, numerical, and spatial abilities, four measures of domain knowledge, and 27 measures of personality and motivational traits, vocational interests, and self-assessments. Both ability and non-ability trait composites were significant predictors of academic performance, but only the non-ability trait composites predicted job performance. Implications for the integrative assessment of individual differences and their predictive validities for performance in different active work contexts, as well as the importance of trait composites across contexts, are discussed. Un ensemble de mesures relatives aux connaissances, aux aptitudes et autres dimensions furent obtenues aupres de 105 etudiants de 1° cycle impliques dans un programme de travail scolaire cooperatif, avec pour objectif de predire les resultats universitaires et la performance au travail. Des scores composites pour chacun de ces deux domaines ont ete constitues a partir d'analyses factorielles des onze mesures des aptitudes verbale, numerique et spatiale, des quatre mesures portant sur les connaissances et des 27 mesures relevant de traits de personnalite, de la motivation, des interets professionnels et de l'auto-evaluation. Les scores des aptitudes et des traits de personnalite furent des predicteurs significatifs du succes universitaire, mais seuls ces derniers ont predit la performance au travail. On reflechit aux consequences sur l'evaluation synthetique des differences individuelles et leur validite predictive de la performance dans differents contextes de travail productif, ainsi que sur l'importance des scores composites selon les situations.

Mothers can determine which genotypes of offspring they will produce through selective abortion or selective implantation. This process can, at some loci, favour matching between maternal and offspring genotype whereas at other loci mismatching may be favoured (e.g. MHC, HLA). Genomic imprinting generally renders gene expression monoallelic and could thus be adaptive at loci where matching or mismatching is beneficial. This hypothesis, however, remains unexplored despite evidence that loci known to play a role in genetic compatibility may be imprinted. We develop a simple model demonstrating that, when matching is beneficial, imprinting with maternal expression is adaptive because the incompatible paternal allele is not detected, protecting offspring from selective abortion. Conversely, when mismatching is beneficial, imprinting with paternal expression is adaptive because the maternal genotype is more able to identify the presence of a foreign allele in offspring. Thus, imprinting may act as a genomic 'cloaking device' during critical periods in development when selective abortion is possible.

Interactions between cytoplasmic (generally organelle) and nuclear genomes may be relatively common and could potentially have major fitness consequences. As in the case of within-genome epistasis, this cytonuclear epistasis can favor the evolutionary coadaptation of high-fitness combinations of nuclear and cytoplasmic alleles. Because cytoplasmic factors are generally uniparentally inherited, the cytoplasmic genome is inherited along with only one of the nuclear haplotypes, and therefore, coadaptation is expected to evolve through the interaction of these coinherited (usually maternally inherited) genomes. Here I show that, as a result of this coinheritance of the two genomes, cytonuclear epistasis can favor the evolution of genomic imprinting such that, when the cytoplasmic factor is maternally inherited, selection favors maternal expression of the nuclear locus and when the factor is paternally inherited selection favors paternal expression. Genomic imprinting evolves in this model because it leads to a pattern of gene expression in the nuclear haplotype that is coadapted with (i.e., adaptively coordinated with) gene expression in the coinherited cytoplasmic genome.

Results are presented from an intercomparison of single-column and cloud-resolving model simulations of a cold-air outbreak mixed-phase stratocumulus cloud observed during the Atmospheric Radiation Measurement (ARM) programme's Mixed-Phase Arctic Cloud Experiment. The observed cloud occurred in a well-mixed boundary layer with a cloud-top temperature of −15 ◦ C. The average liquid water path of around 160 g m −2 was about two-thirds of the adiabatic value and far greater than the average mass of ice which when integrated from the surface to cloud top was around 15 gm −2 . Simulations of 17 single-column models (SCMs) and 9 cloud-resolving models (CRMs) are compared. While the simulated ice water path is generally consistent with observed values, the median SCM and CRM liquid water path is a factor-of-three smaller than observed. Results from a sensitivity study in which models removed ice microphysics suggest that in many models the interaction between liquid and ice-phase microphysics is responsible for the large model underestimate of liquid water path. Despite this underestimate, the simulated liquid and ice water paths of several models are consistent with observed values. Furthermore, models with more sophisticated microphysics simulate liquid and ice water paths that are in better agreement with the observed values, although considerable scatter exists. Although no single factor guarantees a good simulation, these results emphasize the need for improvement in the model representation of mixed-phase microphysics. Copyright c � 2009 Royal Meteorological Society

We present here a detailed study of the genetic contributions to adult body size and adiposity in the LG,SM advanced intercross line (AIL), an obesity model. This study represents a first step in fine-mapping obesity quantitative trait loci (QTLs) in an AIL. QTLs for adiposity in this model were previously isolated to chromosomes 1, 6, 7, 8, 9, 12, 13, and 18. This study focuses on heritable contributions and the genetic architecture of fatpad and organ weights. We analyzed both the F(2) and F(3) generations of the LG,SM AIL population single-nucleotide polymorphism (SNP) genotyped with a marker density of approximately 4 cM. We replicate 88% of the previously identified obesity QTLs and identify 13 new obesity QTLs. Nearly half of the single-trait QTLs were sex-specific. Several broad QTL regions were resolved into multiple, narrower peaks. The 113 single-trait QTLs for organs and body weight clustered into 27 pleiotropic loci. A large number of epistatic interactions are described which begin to elucidate potential interacting molecular networks. We present a relatively rapid means to obtain fine-mapping details from AILs using dense marker maps and consecutive generations. Analysis of the complex genetic architecture underlying fatpad and organ weights in this model may eventually help to elucidate not only heritable contributions to obesity but also common gene sets for obesity and its comorbidities.

Results of an ongoing prospective study of progeny of patients with adult-onset polycystic kidney disease using grey-scale ultrasound and high-dose nephrotomography are reported. Six asymptomatic subjects out of 17 at risk for polycystic kidney disease were found by ultrasonography to have multiple renal cysts; this included two unrelated children aged 18 months and 6 y who had normal high-dose nephrotomography. We suggest that ultrasonography may be the method of choice for presymptomatic detection of polycystic kidney disease. Serial studies of at-risk individuals by sonography will be useful in determining the earliest age of detection, the latest age of ultrasonography presentation, and in following the natural history of polycystic kidney disease.

The paradoxical persistence of heritable variation for fitness-related traits is an evolutionary conundrum that remains a preeminent problem in evolutionary biology. Here we describe a simple mechanism in which social competition results in the evolutionary maintenance of heritable variation for fitness related traits. We demonstrate this mechanism using a genetic model with two primary assumptions: the expression of a trait depends upon success in social competition for limited resources; and competitive success of a genotype depends on the genotypes that it competes against. We find that such social competition generates heritable (additive) genetic variation for "competition-dependent" traits. This heritable variation is not eroded by continuous directional selection because, rather than leading to fixation of favored alleles, selection leads instead to allele frequency cycling due to the concerted coevolution of the social environment with the effects of alleles. Our results provide a mechanism for the maintenance of heritable variation in natural populations and suggest an area for research into the importance of competition in the genetic architecture of fitness related traits.

Indirect genetic effects arise when genes expressed in one individual affect the expression of traits in other individuals. The importance of indirect genetic effects has been recognized for a diversity of evolutionary processes including kin selection, sexual selection, community structure and multilevel selection, but data regarding their genetic architecture and prevalence throughout the genome remain scarce, especially for interactions between unrelated individuals. Using a set of 411 Bay-0 x Shahdara Arabidopsis recombinant inbred lines grown with Landsberg neighbours, we examined quantitative trait loci (QTL) having direct and indirect effects on size, developmental, and fitness related traits. Using an interval mapping approach, we identified 15 QTL with direct effects and found that 13 of these QTL had significant indirect effects on trait expression in neighbouring plants. These results suggest widespread pleiotropy, as nearly all direct effect QTL have associated pleiotropic indirect effects. Paradoxically, most indirect effects were of the same sign as direct effects, creating a pattern of nearly universal positive pleiotropy that makes most covariances between direct and indirect effects positive. These results are consistent with a complex genetic basis for intraspecific interactions, but suggest that interactions between neighbouring plants are largely positive, rather than negative as would be expected for competition. In addition to their evolutionary and ecological importance, these pleiotropic relationships between DGE and IGE loci have implications for quantitative genetic studies of natural populations as well as experimental design considerations. Additionally, studies that ignore IGEs may over- or underestimate quantitative genetic parameters, as well as the effect of and variance contributed by QTL.

Evolution is best viewed as a multivariate process making a working knowledge of linear algebra a great aide in our understanding of this process (Lande & Arnold, 1983; Manley, 1985; Endler, 1986; Phillips & Arnold, 1989). We therefore are in general agreement with the main thrust of Blows’ (2007) argument – a fuller appreciation of multivariate methods, particularly those that employ the diagonalization of the G and c matrices, can aid our understanding of microevolutionary change. Nevertheless, the approach advocated by Blows (2007) is not a panacea that solves all problems in multivariate evolutionary analyses, and there are circumstances where the diagonalization of the G and c matrices is either inappropriate or inferior to alternatives. In our opinion, the utility of matrix diagonalization is largely determined by the particular question of interest and the biology of the system examined. In support of our arguments, we discuss how matrix diagonalization can obscure the biological interpretation of a complex data set. We then discuss how the benefits of matrix diagonalization in evolutionary studies vary with the specific question addressed.

The contribution that pleiotropic effects of individual loci make to covariation among traits is well understood theoretically and is becoming well documented empirically. However, little is known about the role of epistasis in determining patterns of covariation among traits. To address this problem we combine a quantitative trait locus (QTL) analysis with a two-locus model to assess the contribution of epistasis to the genetic architecture of variation and covariation of organ weights and limb bone lengths in a backcross population of mice created from the M16i and CAST/Ei strains. Significant epistasis was exhibited by 14 pairwise combinations of QTL for organ weights and 10 combinations of QTL for limb bone lengths, which contributed, on average, about 5% of the variation in organ weights and 8% in limb bone lengths beyond that of single-locus QTL effects. Epistatic pleiotropy was much more common in the limb bones (seven of 10 epistatic combinations affecting limb bone lengths were pleiotropic) than the organs (three of the 14 epistatic combinations affecting organ weights were pleiotropic). In both cases, epistatic pleiotropy was less common than single-locus pleiotropy. Epistatic pleiotropy accounted for an average of 6% of covariation among organ weights and 21% of covariation among limb bone lengths, which represented an average of one-fifth (for organ weights) and one-third (for limb bone lengths) of the total genetic covariance between traits. Thus, although epistatic pleiotropy made a smaller contribution than single-locus pleiotropy, it clearly made a significant contribution to the genetic architecture of variation/covariation.

The traditional means of preparing community college leaders are disjointed and in many cases ill suited to meet the challenges leaders will face through the beginning decades of the twenty-first century. Community colleges must take a proactive role in the development of their future leaders.

This study reports the Single-Column Model (SCM) part of the Atmospheric Radiation Measurement (ARM)/the Global Energy and Water Cycle Experiment (GEWEX) Cloud System Study (GCSS) joint SCM and Cloud-Resolving Model (CRM) Case 3 intercomparison study, with a focus on evaluation of cumulus parametrizations used in SCMs. Fifteen SCMs are evaluated under summertime midlatitude continental conditions using data collected at the ARM Southern Great Plains site during the summer 1997 Intensive Observing Period. Results from ten CRMs are also used to diagnose problems in the SCMs. It is shown that most SCMs can generally capture well the convective events that were well-developed within the SCM domain, while most of them have difficulties in simulating the occurrence of those convective events that only occurred within a small part of the domain. All models significantly underestimate the surface stratiform precipitation. A third of them produce large errors in surface precipitation and thermodynamic structures. Deficiencies in convective triggering mechanisms are thought to be one of the major reasons. Using a triggering mechanism that is based on the vertical integral of parcel buoyant energy without additional appropriate constraints results in overactive convection, which in turn leads to large systematic warm/dry biases in the troposphere. It is also shown that a non-penetrative convection scheme can underestimate the depth of instability for midlatitude convection, which leads to large systematic cold/moist biases in the troposphere. SCMs agree well quantitatively with CRMs in the updraught mass fluxes, while most models significantly underestimate the downdraught mass fluxes. Neglect of mesoscale updraught and downdraught mass fluxes in the SCMs contributes considerably to the discrepancies between the SCMs and the CRMs. In addition, uncertainties in the diagnosed mass fluxes in the CRMs and deficiencies with cumulus parametrizations are not negligible. Similar results are obtained in the sensitivity tests when different forcing approaches are used. Finally, sensitivity tests from an SCM indicate that its simulations can be greatly improved when its triggering mechanism and closure assumption are improved. © Royal Meteorological Society, 2002. J. C. Petch's contribution is Crown copyright.

There has been a long-standing conceptual debate over the legitimacy of assigning components of offspring fitness to parents for purposes of evolutionary analysis. The benefits and risks inherent in assigning fitness of offspring to parents have been given primarily as verbal arguments and no explicit theoretical analyses have examined quantitatively how the assignment of fitness can affect evolutionary inferences. Using a simple quantitative genetic model, we contrast the conclusions drawn about how selection acts on a maternal character when components of offspring fitness (such as early survival) are assigned to parents vs. when they are assigned directly to the individual offspring. We find that there are potential shortcomings of both possible assignments of fitness. In general, whenever there is a genetic correlation between the parental and direct effects on offspring fitness, assigning components of offspring fitness to parents yields incorrect dynamical equations and may even lead to incorrect conclusions about the direction of evolution. Assignment of offspring fitness to parents may also produce incorrect estimates of selection whenever environmental variation contributes to variance of the maternal trait. Whereas assignment of offspring fitness to the offspring avoids these potential problems, it introduces the possible problem of missing components of kin selection provided by the mother, which may not be detected in selection analyses. There are also certain conditions where either model can be appropriate because assignment of offspring fitness to parents may yield the same dynamical equations as assigning offspring fitness directly to offspring. We discuss these implications of the alternative assignments of fitness for modelling, selection analysis and experimentation in evolutionary biology.

A set of both enantiomeric forms of non-proteinogenic, unsaturated α-H-α-amino acids was efficiently synthesized using a biocatalytic pathway. This route involved the straightforward synthesis of the required unsaturated amino acid amides, followed by resolution with an aminopeptidase present in Pseudomonas putida ATCC 12633 and/or a genetically modified organism, leading to the (S)-acids and (R)-amides. Undesired amino acid racemase activity was identified in the wild-type strain, which was absent in the newly developed organism. The (R)-amides were hydrolyzed under mild conditions using an amidase present in whole cells from Rhodococcus erythropolis NCIMB 11540 to the (R)-acids. The viability of this procedure was demonstrated with the multi-gram synthesis of a variety of unsaturated amino acids in excellent enantiopurity.

Theoretical analyses have demonstrated a potential role for epistasis in many of the most important processes in evolution. These analyses generally assume that an individual's genes map directly to its phenotype and epistasis results from interactions among loci that contribute to the same biochemical or developmental pathways (termed physiological, or within-genotype, epistasis). For many characters, particularly those expressed early in life, an in- dividual's phenotype may also be affected by genes expressed by its parents. The presence of these parental effects allows for interactions between the genes present in the parental and offspring genomes. When the phenotypic effect of a locus in the offspring depends on the alleles possessed by its parents, genotype-by-genotype, or among-genotype, epistasis occurs. The among-genotype epistasis resulting from parental effects may contribute to ruggedness of adaptive landscapes because early mortality often accounts for much of the variance in fitness in populations. To demonstrate how parent-offspring interactions can result in among-genotype epistasis, I use a two-locus model, with one maternal effect locus and one direct effect locus, each with two alleles. Dynamical equations are presented for the two-locus model and are directly contrasted with the dynamical equations derived for a model for physiological epistasis. The relationship between the evolutionary dynamics resulting from these two forms of epistasis is discussed. Three scenarios are presented to illustrate systems in which maternal-offspring, genotype-by-genotype epistasis may occur. The im- plications of maternal-offspring epistasis for quantitative-trait-loci studies are also discussed.

Objective:To determine the interactions of endothelin-1 (ET-1) and nitric oxide (NO) in the regulation of endothelial barrier function in skeletal muscle. Methods:The protein sieving coefficient (1 − σf) was measured as an index of microvascular permeability in the isolated, perfused cat hindlimb preparation. The measurement was made to determine 1) the effects of ET-1 and NO on basal permeability by blocking the ETAreceptor with BQ123 and NO production with the NO-synthase inhibitors L-NAME or L-NMMA; 2) if elevated NO (SNAP) affects permeability; and 3) the interaction of ET-1 and NO by ascertaining if NO-synthase inhibition or elevated NO can block the ET-1-induced permeability increases. Additionally, vascular resistance was determined under these conditions to see if increased microvascular pressures or increased shear stress might play a role in the permeability changes. Results:Blocking either the ETAreceptor or basal NO production did not affect basal permeability. Likewise, raising NO levels did ...

X-ray powder diffraction and Rietveld refinement were used to investigate the structural details of the ThMn 12 -type compounds in the Fe-Gd-Mo ternary system. It has been shown that 8(f)- and 8(j)-crystallographic sites are partially filled with only Fe atoms. The 2(a)-site filled exclusively by Gd and the 8(i)-site that allows mixing of Fe and Mo was found to be completely occupied. It has been established that ThMn 12 -type structure allows a small part of Gd atoms to be located on the 8(i)-positions (antistructural defects). The experimentally measured mass density of the compact samples was compared with the theoretical densities calculated on the base of different possible defect structures. The best agreement was achieved under the assumption that two types of defects are present simultaneously: vacancies on Fe sites and Gd atoms substituting for Fe atoms.

Different hardness measures as Vickers, Brinell and Meyer hardness are discussed with respect to their physical interpretation. Meyer hardness is found to be best suited as a measure of plastic properties. The outline of a depth sensing nanoindentation experiment is described, and particular emphasis is given to the correct deduction of the contact area from indenter penetration data. Experimental complications, as phase transformations, finite machine compliance, thermal and pieco drift, and sample creep are detailed with, and their impact on the calculation of hardness and elastic modulus is shown. Furthermore the onset of yielding in dependence on critical load, indenter curvature and yield strength is discussed.

Hardness and elastic modulus of the icosahedral quasicrystal Al 70 Pd 21 Mn 9 (in the following simply denoted as AlPdMn) have been probec by micro- and nanoindentation in the temperature range from room temperature to 820 K. Pronounced indentation size effects (ISE) were found that result in a hardness increase with decreasing force at room temperature and in the inverse behaviour for elevated temperatures. Furthermore, considerable indentation creep was observed for temperatures above 670 K. Atomic force microscopy (AFM) was utilised to both quantify the impression contact area and to study the development of surface modifications and crack propagation around the indents. The elastic modulus exhibits a linear decrease with raising temperature which is considerably smaller than observed for metals, but somewhat higher than in case of elemental semiconductors.

Single-quasicrystaltine icosahedral AlPdMn was subject to Vickers microindentations at room temperature, annealed up to 750°C in vacuum, and then inspected using optical microscopy, atomic force microscopy (AFM), wavelength dispersive microanalysis (WDX) and Auger spectroscopy (AES). At temperatures above 600°C the whole sample surface became increasingly rough, exhibiting holes and small elevations, whereas the vicinity of the impressions remained free of surface alterations. The growth of large hillocks out of the impressions was observed at temperatures above 700°C in the presence of oxygen. No growth of high elevations was noted for an oxygen partial pressure below 3 x 10 -6 Pa. AES and WDX revealed an enrichment of manganese and the depletion of aluminium in the hillocks. The results are discussed in the frame of indentation induced defects and their impact on diffusion and surface migration.

Objective:To investigate the ability of continuous-distribution pore models to accurately predict permeability-surface area product (PS) experimental data in skeletal muscle. Methods:Models having a water-only (WO) pathway and continuous distributions of microvascular transport-pathway sizes were fit to solute reflection-coefficient (σ) experimental data (∼0.5–16 nm Stokes radii) obtained from skeletal muscle to determine optimal parameter values. Without further modification, these models were used to predict experimental PS values obtained from the literature for small solutes ranging in size from NaCl to inulin and for three proteins, α-lactalbumin, ovalbumin, and albumin (∼ 0.23–3.7 nm radii). The protein PSs were determined from fluorescent tracer-diffusion curves and a nonlinear model of tracer diffusion in the cat hindlimb preparation. The model's PS predictions were compared to those of a discrete-pore model previously developed and a fiber-matrix (FM) model. Results:A log-normal (LN) continuous p...

Interacting phenotypes are traits whose expression is affected by interactions with conspecifics. Commonly- studied interacting phenotypes include aggression, courtship, and communication. More extreme examples of inter- acting phenotypes-traits that exist exclusively as a product of interactions-include social dominance, intraspecific competitive ability, and mating systems. We adopt a quantitative genetic approach to assess genetic influences on interacting phenotypes. We partition genetic and environmental effects so that traits in conspecifics that influence the expression of interacting phenotypes are a component of the environment. When the trait having the effect is heritable, the environmental influence arising from the interaction has a genetic basis and can be incorporated as an indirect genetic effect. However, because it has a genetic basis, this environmental component can evolve. Therefore, to consider the evolution of interacting phenotypes we simultaneously consider changes in the direct genetic contributions to a trait (as a standard quantitative genetic approach would evaluate) as well as changes in the environmental (indirect genetic) contribution to the phenotype. We then explore the ramifications of this model of inheritance on the evolution of interacting phenotypes. The relative rate of evolution in interacting phenotypes can be quite different from that predicted by a standard quantitative genetic analysis. Phenotypic evolution is greatly enhanced or inhibited depending on the nature of the direct and indirect genetic effects. Further, unlike most models of phenotypic evolution, a lack of variation in direct genetic effects does not preclude evolution if there is genetic variance in the indirect genetic contributions. The available empirical evidence regarding the evolution of behavior expressed in interactions, although limited, supports the predictions of our model.

In the present publication, a method to identify and distinguish between different types of low-density polyethylene based on thermal fractionation and FTIR analysis is described. It was shown that during thermal fractionation four to seven endothermic peaks are obtained as opposed to one or two peaks obtained during regular differential scanning calorimetric analysis. The ration between band heights at 1368 and 1376 cm−1 was found to represent the length of the side chain (branch). © 1996 John Wiley & Sons, Inc.

The paper discusses general questions of friction and wear from the point of material sensitivity in AFM studies. The depth of generated grooves after scanning under high load proved a tool of material characterization. The erosion depth was found to sensitively depend on the scanning speed. A model for quantitative discussion of this phenomenon is presented, which also explains the relation between external load and lateral friction force. Allgemeine Fragen von Reibung und Verschleis werden unter dem Aspekt der Materialidentifizierung in atomkraftmikroskopischen Studien diskutiert. Die Tiefe erzeugter Gruben nach Rastern unter relativ hoher Last kann zur Materialcharakterisierung herangezogen werden. Dabei wurde eine Abhangigkeit des Materialabtrags von der Scangeschwindigkeit festgestellt. Ein Modell zur Quantifizierung dieses Phanomens wird vorgeschlagen, welches auch den Zusammenhang zwischen eingebrachter Last und lateraler Reibungskraft hinreichend gut erklart.

NiAl covered with native oxide is oxidized under UHV conditions with controlled oxygen exposures up to 22 × 103 L at T = 940 K and p = 4 × 10−4 Pa. Scanning tunneling spectroscopy and current imaging of oxidized samples reveal that the usual constant current image cannot be interpreted as height profile of the sample. As a consequence of a laterally varying oxide thickness or composition, constant current imaging is more sensitive to thickness and/or composition contrast than to height variations. As shown by I–z spectroscopy, the tip is in mechanical contact with the sample in regions of higher resistance of the oxide layer. For predominating thickness contrast, this effect permits to obtain a lateral cross section of the oxide thickness profile as a function of the oxygen exposure. AES depth profiling suggested the growth of an oxide layer of about 2 nm thickness, when exposing the sample to 22 × 103 L oxygen.

Background. Cyclosporin was used in an attempt to suppress the formation of human antimouse antibody (HAMA) after administration of murine monoclonal antibodies. Methods. Thirteen patients were given oral cyclosporin (8.6-15 mg/kg/day) starting 2 days before administration of technetium-99m ( 99m Tc) labeled F(ab') 2 (3 patients) or Fab (10 patients) murine antibody fragment. Six to nine days later, patients received either rhenium-186 ( 186 Re)-labeled F(ab') 2 or an intact antibody

C1-[18F]fluoroethylamino asparagine was synthesised from N1-t-boc C1-p-nitrophenol asparagine and the radiolabelled precursor [18F]flouroethylamine in a one-pot-synthesis. The yield of this synthesis was 22% referring to [18F]fluoride, including the removal of the protection groups. The in vivo tests are in progress.

By choosing the right substituents either highly functionalized unusual four-membered ring amino acids or the isomeric pipecolic acid derivatives are obtained in enantiomerically pure form. Starting material is a linear allene-containing amino acid that has been resolved via biocatalysis.

Enantiomerically pure acetylene-containing - amino acids were used as versatile starting materials for the synthesis of a variety of heterocycles via Pd-mediated cyclization reactions. Depending on the protecting group strategy, both the carboxylate and the amine function of the amino acids could participate in the cyclizations, thus giving rise to oxygen heterocycles (-aminolactones) and nitrogen heterocycles (cyclic -amino acid derivatives), respectively. Beside the straightforward cyclization, cyclization/cross- coupling reactions were also successfully carried out to provide the corresponding substituted cyclic amino acid derivatives.

Precise thermal control of Knudsen-type evaporation cells in MBE requires basic knowledge on the thermal behaviour of the cell on any alteration of the heating power. This paper deals with the cell's response in temperature, when the cell is subject to a jumplike change in heating power. Particular care is devoted to deviations from pure exponential behaviour, if the temperature transition function between two equilibrium states is concerned. It is shown, that the jump response function for a finite increase in heating power is equivalent to that of an infinite small one, whereby an effective temperature — amounting to 70% of the temperature jump height — has to be introduced.

Molecular beam epitaxy (MBE) takes advantage of crucibles indirectly heated by an electric resistance heater. These thermal sources can be used to evaporate a great variety of materials. A precise control of the evaporation rate, however, requires a temperature stability of about 1‰. Therefore, a detailed knowledge on the thermal behaviour of the source is indispensible. It is intended to present models describing the response of the source temperature to a step change in heating power and compare the results by experimental data. Fur die Molekularstrahlepitaxie (MBE) verwendet man Tiegel, die durch einen elekrischen Widerstandsheizer geheizt werden. Eine Vielzahl von Materialien last sich mit thermischen Quellen verdampfen. Die genaue Steuerung und Regelung der Verdampfungsrate erfordert jedoch eine Temperaturkonstanz von ungefahr 1‰. Deshalb sind genaue Kenntnisse des thermischen Verhaltens der Quelle notwendig. Es Werden einerseits Modelle zur Beschreibung des zeitlichen Verlaufes der Quellentemperatur nach sprunghafter Anderung der Heizleistung und andererseits experimentelle Ergebnisse zur Charakterisierung der Quelle vorgestellt.