Kooperativer Bibliotheksverbund

Berlin Brandenburg

and
and

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Elsevier (CrossRef)  (108)
Type of Medium
Language
Year
  • 1
    Language: English
    In: Gait & Posture, January 2015, Vol.41(1), pp.258-262
    Description: The dual-process account of sensorimotor-cognitive interactions postulates that easy cognitive tasks can lead to performance improvements in the motor domain (e.g., an increased stability while walking or balancing) across the lifespan. However, cross-domain resource competition can lead to performance decrements in motor tasks when the concurrent cognitive task is very difficult, and older adults have shown performance decrements in their motor functioning under such circumstances. Resource limitations are particularly pronounced not only in old adulthood, but also in childhood. The current study investigates the relationship of walking speed and cognitive load on walking regularity in 7- and 9-year olds and young adults, with 18 participants in each group. Participants were walking on a treadmill at their preferred speed, and with speeds that were 30% faster and 30% slower than preferred. Regularity of lower-body coordination was operationalized as the residual variance of principal component analyses performed on the data of a motion analysis system. All age groups showed a more regular gait with increasing walking speed. Young adults’ gait regularity was not influenced by cognitive load, whereas children showed a U-shaped relationship of cognitive load and walking regularity, with the highest regularity when performing an easy cognitive task. It can be concluded that children are also influenced by cross-domain resources competition in challenging cognitive-motor dual-task situations.
    Keywords: Dual-Task ; Walking ; Cognition ; Children ; Young Adults ; Medicine ; Anatomy & Physiology
    ISSN: 0966-6362
    E-ISSN: 1879-2219
    E-ISSN: 14321106
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 2
    Language: English
    In: Gait & Posture, 2011, Vol.33(3), pp.401-405
    Description: We investigated dual-task performance of cognitive (semantic fluency) and sensorimotor tasks (walking) in 120 children and adults from four age groups (9-year olds, = 9.52 years; 11-year olds, = 11.51 years; young adults, = 25.34 years; older adults, = 64.28 years; = 30 per group). Distances walked during 90 s and numbers of category exemplars generated in the semantic fluency task showed an inverted U-shape function with age. In line with general resource models proportional dual-task costs in walking also showed a U-shaped relation as a function of age with pronounced decrements in the youngest and oldest groups. Only 9-year olds showed significant costs in the cognitive task. Individual differences in single-task performance accounted for more than half of the variance in dual-task performance. Reliable age-related residual variance implicated additional factors particularly in children's developing multi-tasking performances.
    Keywords: Dual-Task ; Lifespan ; Semantic Fluency ; Cognitive Resources ; Medicine ; Anatomy & Physiology
    ISSN: 0966-6362
    E-ISSN: 1879-2219
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 3
    Language: English
    In: Chemosphere, November 2015, Vol.138, pp.856-862
    Description: Equilibrium sampling can be applied to measure freely dissolved concentrations ( ) of hydrophobic organic chemicals (HOCs) that are considered effective concentrations for diffusive uptake and partitioning. It can also yield concentrations in lipids at thermodynamic equilibrium with the sediment ( ) by multiplying concentrations in the equilibrium sampling polymer with lipid to polymer partition coefficients. We have applied silicone coated glass jars for equilibrium sampling of seven ‘indicator’ polychlorinated biphenyls (PCBs) in sediment samples from ten locations along the River Elbe to measure of PCBs and their . For three sites, we then related to lipid-normalized PCB concentrations ( ) that were determined independently by the German Environmental Specimen Bank in common bream, a fish species living in close contact with the sediment: (1) In all cases, were below , (2) there was proportionality between the two parameters with high values (0.92–1.00) and (3) the slopes of the linear regressions were very similar between the three stations (0.297; 0.327; 0.390). These results confirm the close link between PCB bioaccumulation and the thermodynamic potential of sediment-associated HOCs for partitioning into lipids. This novel approach gives clearer and more consistent results compared to conventional approaches that are based on total concentrations in sediment and biota-sediment accumulation factors. We propose to apply equilibrium sampling for determining bioavailability and bioaccumulation potential of HOCs, since this technique can provide a thermodynamic basis for the risk assessment and management of contaminated sediments.
    Keywords: Equilibrium Sampling ; Sediment ; Bioaccumulation ; Polychlorinated Biphenyl (Pcb) ; River Elbe ; Freely Dissolved Concentration (Cfree) ; Chemistry ; Ecology
    ISSN: 0045-6535
    E-ISSN: 1879-1298
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 4
    Language: English
    In: NeuroImage, 01 May 2016, Vol.131, pp.155-161
    Description: This study investigates the effects of fitness changes on hippocampal microstructure and hippocampal volume. Fifty-two healthy participants aged 59–74 years with a sedentary lifestyle were randomly assigned to either of two levels of exercise intensity. Training lasted for six months. Physical fitness, hippocampal volumes, and hippocampal microstructure were measured before and after training. Hippocampal microstructure was assessed by mean diffusivity, which inversely reflects tissue density; hence, mean diffusivity is lower for more densely packed tissue. Mean changes in fitness did not differ reliably across intensity levels of training, so data were collapsed across groups. Multivariate modeling of pretest–posttest differences using structural equation modeling (SEM) revealed that individual differences in latent change were reliable for all three constructs. More positive changes in fitness were associated with more positive changes in tissue density (i.e., more negative changes in mean diffusivity), and more positive changes in tissue density were associated with more positive changes in volume. We conclude that fitness-related changes in hippocampal volume may be brought about by changes in tissue density. The relative contributions of angiogenesis, gliogenesis, and/or neurogenesis to changes in tissue density remain to be identified.
    Keywords: Aging ; Fitness ; Physical Exercise ; Hippocampal Volume ; Hippocampal Microstructure ; Latent Difference Modeling ; Medicine
    ISSN: 1053-8119
    E-ISSN: 1095-9572
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 5
    Language: English
    In: NeuroImage, 15 February 2012, Vol.59(4), pp.3389-3397
    Description: A widespread network involving cortical and subcortical brain structures forms the neural substrate of human spatial navigation. Most studies investigating plasticity of this network have focused on the hippocampus. Here, we investigate age differences in cortical thickness changes evoked by four months of spatial navigation training in 91 men aged 20–30 or 60–70 years. Cortical thickness was automatically measured before, immediately after, and four months after termination of training. Younger as well as older navigators evidenced large improvements in navigation performance that were partly maintained after termination of training. Importantly, training-related cortical thickening in left precuneus and paracentral lobule were observed in young navigators only. Thus, spatial navigation training appears to affect cortical brain structure of young adults, but there is reduced potential for experience-dependent cortical alterations in old age.
    Keywords: Cortical Thickness ; Plasticity ; Spatial Navigation ; Aging ; Medicine
    ISSN: 1053-8119
    E-ISSN: 1095-9572
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 6
    Language: English
    In: Marine Environmental Research, 2011, Vol.71(1), pp.70-78
    Description: Female and male individuals of the same species often differ with respect to their susceptibility to toxicant stress. In the present study, sea urchins ( ) of both sexes were exposed to high (150 μg L ) and environmentally relevant (5 μg L ) concentrations of phenanthrene over 10 days. While food intake was significantly decreased following exposure to 150 μg L phenanthrene, histological indices (lipofuscin accumulation, fibrosis, oocyte atresia), energetic status (energy charge, sum adenylates, AMP/ATP ratio) as well as ascorbate levels in the gonads showed either little or no effect upon phenanthrene exposure. However, most parameters (vitamin C, energy charge, sum adenylates, AMP/ATP ratio, ATP and ADP concentrations, lipofuscin content, fibrosis) significantly differed between male and female animals. This study illustrates the difficulties to identify toxic injury in reproductive tissue as it may be superimposed by gametogenesis and spawning of gametes.
    Keywords: Sea Urchin ; Gonad ; Lipofuscin ; Energy Charge ; Phenanthrene ; Ascorbate ; Sex-Specific Differences ; ATP ; ATP/Amp Ratio ; Gametogenesis ; Environmental Sciences ; Biology ; Oceanography ; Ecology
    ISSN: 0141-1136
    E-ISSN: 1879-0291
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 7
    Language: English
    In: Molecular Plant, 02 March 2015, Vol.8(3), pp.479-481
    Description: 摘 要: Dear Editor, The Arabidopsis CONSTITUTIVELY PHOTOMORPHOGENIC1/ SUPPRESSOR OF PHYA-105 (COP1/SPA) complex is a key repressor of light signaling that inhibits light responses in dark- ness. It acts as an E3 ubiquitin ligase, which ubiquitinates posi- tively acting light-signaling intermediates, mainly transcription factors, thereby targeting them for proteolytic degradation by the 26S proteasome. In the light, photoreceptors directly interact with the COP1/SPA complex, leading to its inactivation, which subsequently allows the target transcription factors to accumu- late and initiate vast reprogramming of gene expression (Huang et al., 2014).
    Keywords: Botany
    ISSN: 1674-2052
    E-ISSN: 1752-9867
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 8
    Language: English
    In: The American Journal of Pathology, November 2014, Vol.184(11), pp.2922-2935
    Description: Oxyphil cell transformation of epithelial cells due to the accumulation of mitochondria occurs often during cellular aging. To understand the pathogenic mechanisms, we studied mitochondrial DNA (mtDNA) alterations in the three cell types of the parathyroids using multiplex real-time PCR and next-generation sequencing. mtDNA was analyzed from cytochrome oxidase (COX)–positive and COX-negative areas of 19 parathyroids. Mitochondria-rich pre-oxyphil/oxyphil cells were more prone to develop COX defects than the mitochondria-poor clear chief cells (  〈 0.001). mtDNA increased approximately 2.5-fold from clear chief to oxyphil cells. In COX deficiency, the increase was even more pronounced, and COX-negative oxyphil cells had approximately two times more mtDNA than COX-positive oxyphil cells (  〈 0.001), illustrating the influence of COX deficiency on mtDNA biosynthesis, probably as a consequence of insufficient ATP synthesis. Next-generation sequencing revealed a broad spectrum of putative pathogenic mtDNA point mutations affecting NADH dehydrogenase and COX genes as well as regulatory elements of mtDNA. NADH dehydrogenase gene mutations preferentially accumulated in COX-positive pre-oxyphil/oxyphil cells and, therefore, could be essential for inducing oxyphil cell transformation by increasing mtDNA/mitochondrial biogenesis. In contrast, COX-negative cells predominantly harbored mutations in the and genes and in regulatory mtDNA elements, but only rarely NADH dehydrogenase mutations. Thus, multiple hits in NADH dehydrogenase and COX activity–impairing genes represent the molecular basis of oxyphil cell transformation in the parathyroids.
    Keywords: Medicine
    ISSN: 0002-9440
    E-ISSN: 1525-2191
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 9
    Language: English
    In: Geoderma, 01 September 2018, Vol.325, pp.37-48
    Description: Organic particles including microorganisms are a significant fraction of the mobile organic matter (MOM) pool that contributes to initial pedogenesis. Still, the dynamics and the interplay of the multitude of processes that control the mobilization, transport, and retention of MOM are vastly unclear. We studied this interplay using an ‘artificial soil’ as model for a young, unstructured soil with defined initial composition employing a novel two-layer column experiment. The upstream layer was composed of a mixture of well-defined mineral phases, a sterile organic matter source and a diverse, natural microbial inoculant mimicking an organic-rich topsoil. The downstream layer, mimicking the subsoil, was composed of the mineral phases, only. Columns were run under water-unsaturated flow conditions with multiple flow interruptions to reflect natural flow regimes and to detect possible non-equilibrium processes. Pore system changes caused by flow were inspected by scanning electron microscopy and computed micro-tomography. MOM-related physicochemical effluent parameters and bacterial community diversity and abundance were assessed by molecular analysis of the effluent and the solid phase obtained after the long-term irrigation experiment (75 d). Tomographic data showed homogeneous packing of the fine-grained media (sandy loam). During flow, the initially single-grain structured artificial soil showed no connected macropores. In total, 6% of the initial top layer organic matter was mobile. The release and transport of particulate (1.2%) and dissolved organic matter (4.8%) including bacteria were controlled by non-equilibrium conditions. Bacterial cells were released and selectively transported to downstream layer resulting in a depth-dependent and selective establishment of bacterial communities in the previously sterile artificial soil. This study underlines the importance of bacterial transport from the surface or topsoil for colonization and maturation of downstream compartments. This initial colonization of pristine surfaces is the major step in forming biogeochemical interfaces - the prominent locations of intensive biological activity and element turnover that seem to play a major role for the functioning of soil.
    Keywords: Mobile Organic Matter ; Unsaturated Two-Layer Column Experiment ; Experimental Pedogenesis ; Artificial Soil ; Computed Micro-Tomography ; Molecular Analysis ; Agriculture
    ISSN: 0016-7061
    E-ISSN: 1872-6259
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 10
    Language: English
    In: Colloids and Surfaces A: Physicochemical and Engineering Aspects, 20 April 2019, Vol.567, pp.249-259
    Description: Protein based nanoparticles (NPs) are promising new surface-active ingredients for stabilizing air-in-water or oil-in-water dispersions in food systems. Fundamental knowledge on their structure-function relationship is still lacking. Here, NPs based on wheat gliadins (WGNPs) and maize zeins (MZNPs) were produced using liquid anti-solvent precipitation. MZNPs had much higher surface hydrophobicity (SH) than WGNPs. Defatting of gliadin and zein powders prior to NP production revealed that their endogenous lipids do not impact neither size, surface charge and SH of WGNPs or MZNPs. Thus, the high SH of MZNP could be ascribed solely to its proteins. WGNPs had excellent foaming capacity and foam stability, while foam could barely be formed from MZNPs. The foaming properties of mixed gliadin-zein particles of intermediate SH were worse than expected based on their gliadin contents. The presence of zein in nanoparticles thus resulted in poor foam stability. Interestingly, all foaming characteristics could be related to the build-up of a viscoelastic interfacial protein film upon NP adsorption. Indeed, WGNP had much higher surface dilatational moduli than MZNPs, which was in line with the former’s superior foaming properties. This suggests that for WGNPs and MZNPs to efficiently stabilize interfaces, they need to partially disintegrate and spread at the interface, thereby mutually interacting and forming a coherent viscoelastic protein film.
    Keywords: Air-Water Interface ; Gliadin ; Zein ; Nanoparticles ; Foam ; Surface Hydrophobicity ; Engineering ; Chemistry
    ISSN: 0927-7757
    E-ISSN: 1873-4359
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. Further information can be found on the KOBV privacy pages