bluuebunny/crossref_metadata_2025_split huggingface dataset:
Expertise and aging: maintaining skills through the lifespan
Authors: Horton Sean , Baker Joseph , Schorer Jörg 
Published: April 2008

Abstract
As lifespan continues to increase in many developed countries, so too does the age at which we see extraordinary achievements from older adults. Examples from running, golf, and other domains continue to redefine what is possible as we age. Evidence suggests, however, that progression through adulthood is associated with a dramatic decline in all manner of physical and cognitive abilities, from physiological capacities (e.g., VO2 max) to cognitive and perceptual functions (e.g., IQ scores, reaction time). In the face of such precipitous decline in specific abilities, how do we account for maintenance of skilled performance and expertise amongst those supposedly well along the age-decline curve? Expert performers are seemingly able to sustain high levels of achievement in the face of an overall deterioration in general capacities. Moreover, experts maintain this performance in spite of reduced involvement in their field. There are three primary explanations for the ability of experts to maintain superior performance in spite of an overall decline in abilities: (a) preserved differentiation, (b) compensation, and (c) selective maintenance. Overall, research into the high achievements of older adults may reveal a great deal with respect to skill preservation and how to best counter age-related decline.
Classification of fault breccias and related fault rocks
Authors: WOODCOCK N. H. , MORT K. 
Published: April 2008

AbstractDespite extensive research on fault rocks, and on their commercial importance, there is no non-genetic classification of fault breccias that can easily be applied in the field. The present criterion for recognizing fault breccia as having no ‘primary cohesion’ is often difficult to assess. Instead we propose that fault breccia should be defined, as with sedimentary breccia, primarily by grain size: with at least 30% of its volume comprising clasts at least 2 mm in diameter. To subdivide fault breccias, we advocate the use of textural terms borrowed from the cave-collapse literature – crackle, mosaic and chaotic breccia – with bounds at 75% and 60% clast content. A secondary breccia discriminant, more difficult to apply in the field, is the ratio of cement to matrix between the clasts. Clast-size issues concerning fault gouge, cataclasite and mylonite are also discussed.
Expansion of Human Neural Precursor Cells in Large‐Scale Bioreactors for the Treatment of Neurodegenerative Disorders
Authors: Baghbaderani Behnam A. , Mukhida Karim , Sen Arindom , Hong Murray , Mendez Ivar , Behie Leo A. 
Published: April 2008

AbstractThe transplantation of in vitro expanded human neural precursor cells (hNPCs) represents a potential new treatment alternative for individuals suffering from incurable neurodegenerative disorders such as Parkinson's disease (PD) and Huntington's disease (HD). However, in order for cell restorative therapy to have widespread therapeutic significance, it will be necessary to generate unlimited quantities of clinical grade hNPCs in a standardized method. We report here that we have developed a serum‐free medium and scale‐up protocols that allow for the generation of clinical quantities of human telencephalon‐derived hNPCs in 500‐mL computer‐controlled suspension bioreactors. The average hNPC aggregate diameter in the bioreactors was maintained below a target value of 500 μm by controlling the liquid shear field. The human cells, which were inoculated at 105 cells/mL, exhibited a doubling time of 84 h, underwent a 36‐fold expansion over the course of 18 days, and maintained an average viability of over 90%. The bioreactor‐derived hNPCs retained their nestin expression following expansion and were able to differentiate into glial and neuronal phenotypes under defined conditions. It has also been demonstrated that these hNPCs differentiated to a GABAergic phenotype that has recently been shown to be able to restore functional behavior in rat models of HD and neuropathic pain (Mukhida, K. et al. Stem Cells 2007; DOI 10.1634/stemcells.2007–0326). This study demonstrates that clinical quantities of hNPCs can be successfully and reproducibly generated under standardized conditions in computer‐controlled suspension bioreactors.
Systems Pharmacology
Authors: Iyengar Ravi 
Published: April 2008

AbstractThe slides are from a presentation given by Professor Ravi Iyengar from Mount Sinai School of Medicine at the Drug Forum Meeting 9 that took place in Washington, DC on February 20-21, 2008. The slides describe two projects: one that was published last year, and the other unpublished. These projects used network analysis to explore the relationships between FDA approved drugs and a human protein-protein interaction network.
Glucagon and hyperglycaemia in diabetes
Authors: Cryer Philip E. 
Published: April 2008

Glucagon, in the setting of absolute or relative insulin deficiency, is thought to contribute to the pathogenesis of hyperglycaemia in diabetes, but much of the evidence is extrapolated from short-term studies to the long-term condition. In the present issue of Clinical Science, Li and co-workers report that infusion of glucagon raised fasting plasma glucose concentrations and impaired glucose tolerance over 4 weeks in mice, thus demonstrating a sustained glycaemic effect of hyperglucagonaemia. Nonetheless, compelling evidence that glucagon contributes to the pathogenesis of hyperglycaemia in diabetes awaits long-term selective reduction of glucagon secretion or action in humans.
Assigning functional linkages to proteins using phylogenetic profiles and continuous phenotypes
Authors: Gonzalez Orland , Zimmer Ralf 
Published: April 2008

Abstract
Motivation: A class of non-homology-based methods for protein function prediction relies on the assumption that genes linked to a phenotypic trait are preferentially conserved among organisms that share the trait. These methods typically compare pairs of binary strings, where one string encodes the phylogenetic distribution of a trait and the other of a protein. In this work, we extended the approach to automatically deal with continuous phenotypes.
Results: Rather than use a priori rules, which can be very subjective, to construct binary profiles from continuous phenotypes, we propose to systematically explore thresholds which can meaningfully separate the phenotype values. We illustrate our method by analyzing optimal growth temperatures, and demonstrate its usefulness by automatically retrieving genes which have been associated with thermophilic growth. We also apply the general approach, for the first time, to optimal growth pH, and make novel predictions. Finally, we show that our method can also be applied to other properties which may not be classically considered as phenotypes. Specifically, we studied correlations between genome size and the distribution of genes.
Contact: orlandgonzalez@gmail.com
Supplementary information: Supplementary data are available at Bioinformatics online.
The stochastic Mathieu's equation
Authors: Poulin Francis J , Flierl Glenn R 
Published: April 2008

In this manuscript, we consider generalizations of the classical Mathieu's equation to stochastic systems. Unlike previous works, we focus on internal frequencies that vary continuously between periodic and stochastic variables. By numerically integrating the system of equations using a symplectic method, we determine the Lyapunov exponents for a wide range of parameters to quantify how the growth rates vary in parameter space.
In the nearly periodic limit, we recover the same growth rates as the classical Mathieu's equation. As the stochasticity increases, the maximum growth decreases and the unstable region broadens, which signifies that the stochasticity can both stabilize and destabilize a system in relation to the deterministic limit. In addition to the classical parametric modes, there is also an unstable stochastic mode that arises only for moderate stochasticity. The power spectrum of the solutions shows that an increase in stochasticity tends to narrow the width of the subharmonic peak and increase the decay away from this peak.
Protective effect of nasal immunization of influenza virus hemagglutinin with recombinant cholera toxin B subunit as a mucosal adjuvant in mice
Authors: Isaka Masanori , Zhao Yanqiu , Nobusawa Eri , Nakajima Setsuko , Nakajima Katsuhisa , Yasuda Yoko , Matsui Hideyuki , Hasegawa Tadao , Maeyama Jun‐ichi , Morokuma Kazunori , Ohkuma Kunio , Tochikubo Kunio 
Published: April 2008

ABSTRACTTo develop an efficient nasal influenza vaccine, influenza A and B virus HA with rCTB as a mucosal adjuvant were administered to mice intranasally. Serum anti‐HA IgG and IgA antibody responses for both HA vaccines were significantly increased in the presence of rCTB. Higher HI and neutralizing antibody titers and higher mucosal IgA antibody responses in the respiratory tract were detected when rCTB was added than without rCTB. When mice were immunized with HA vaccine with or without rCTB and challenged by intranasal administration of mouse‐adapted pathogenic influenza A virus, all mice immunized with HA plus rCTB survived for seven days without any inflammatory changes in the lungs, while not all the mice immunized with HA without rCTB survived, and all of them had lung consolidations. These results demonstrate that intranasal co‐administration of rCTB as a mucosal adjuvant with influenza virus HA is necessary not only for the induction of systemic and mucosal HA antibodies, but also for the protection of mice from morbidity and mortality resulting from virus infection.
Human immunodeficiency virus type‐1 vulnerates nascent neuronal cells
Authors: Kitayama Hiroko , Miura Yoshiharu , Ando Yoshinori , Koyanagi Yoshio 
Published: April 2008

ABSTRACTMacrophages or microglial cells are the major target cells for HIV‐1 infection in the brain. The infected cells release neurotoxic factors that may cause severe neuronal cell damage, especially in the basal ganglia and hippocampus. In this study, we used rat OHC to examine the region‐specific neuronal cell damage caused by HIV‐1‐infected macrophages. When OHC was cocultured with HIV‐1‐infected MDM, we found that neuronal cells at the GCL of the DG were preferentially killed via apoptosis, and that projection of MF from GCL to PCL of the CA3 region was severely disturbed. We marked precursor cells around the DG region by using an EGFP‐expressing retrovirus vector and found that these cells lost the ability to differentiate into neurons when exposed to HIV‐1‐infected MDM. In the DG, new neurons are normally incorporated into GCL or PCL, while in the presence of HIV‐1‐infected MDM, mature neurons failed to be incorporated into those layers. These data indicate that the neurotoxic factor(s) released from HIV‐1‐infected macrophages impede(s) neuronal cell repair in brain tissue. This suggests that DG is the region of the hippocampus most vulnerable to neuronal damage caused by HIV‐1 infection, and that its selective vulnerability is most likely due to the highly active neurogenesis that takes place in this region.
The Bordetella type III secretion system: its application to vaccine development
Authors: Abe Akio , Nagamatsu Kanna , Watanabe Mineo 
Published: April 2008

ABSTRACT
B. pertussis is a causative agent of whooping cough (pertussis) in humans. Despite wide‐scale vaccination in many countries, there is serious concern about pertussis as a re‐emerging disease. Re‐emergence of pertussis may be explained by several factors: the short duration of protection by the currently available acellular pertussis vaccine, an increase in asymptomatic adult carriers and expansion of strains with certain antigenic variations which are not covered by currently available vaccines. To develop safer and more efficacious vaccines which confer more prolonged protection, researchers are focusing on identification and characterization of new virulence factors. One candidate for protective antigens is the type III secretion system and its secreted proteins.
Submarine and subaerial erosion of volcanic landscapes: comparing Pacific Ocean seamounts with Valencia Seamount, exposed during the Messinian Salinity Crisis
Authors: Mitchell Neil C. , Lofi Johanna 
Published: April 2008

ABSTRACTSimilarity of form between subaerial and submarine landscapes affected by erosion could suggest similarities in the process of erosion, such as by runoff and sedimentary flows, respectively. On the other hand, if aspects of form vary, its characteristics may be used to identify the environmental origin of erosion. Towards these goals, this contribution addresses the morphology of submarine volcanoes (seamounts) with widely differing histories of erosion. One set from the Pacific Ocean never exposed above sea level includes Cretaceous‐age seamounts near Hawai'i (including Apu'upu'u Seamount), two seamounts of <3 Ma in age near a mid‐ocean ridge and the 11–4 Ma Jasper Seamount. These seamounts are all isolated from continents and hence from any erosion associated with mass wasting of unstable terrigenous deposits. In such isolated submarine environments, surfaces erode slowly from in situ weathering, mass wasting and scouring by sedimentary flows initiated by slope failure in pelagic or bedrock materials. The Pacific seamounts are compared with Valencia Seamount in the western Mediterranean, exposed subaerially for 100–400 k.y. during the Messinian Salinity Crisis before 5 Ma. Multibeam and deeply towed sidescan sonar data of Valencia Seamount reveal features typical of subaerial erosion of volcanic islands, such as canyons and relatively uneroded sectors (planezes) between them. Using a simple topographical reconstruction, the apparent erosion depth typically reaches 100 m within canyons and up to 180 m in places. Whereas the younger Pacific seamounts do not show these erosional features, the much older Cretaceous seamounts do have channels, which in one example suggests up to 200 m of incision. Both Valencia and Apu'upu'u seamounts have channel longitudinal profiles that are steep and typically linear to concave upwards. The erosion depth of Apu'upu'u Seamount is significant, despite the seamount's persistent submarine environment, because of its greater age, steeper flanks and greater contributing areas to channels compared with Valencia Seamount. These results illustrate that the channel morphology resulting from submarine erosion can become similar to that produced by subaerial erosion given sufficient time.
Behavioural flexibility in individuals with Angelman syndrome, Down syndrome, non‐specific intellectual disability and Autism spectrum disorder
Authors: Didden R. , Sigafoos J. , Green V. A. , Korzilius H. , Mouws C. , Lancioni G. E. , O'Reilly M. F. , Curfs L. M. G. 
Published: April 2008

AbstractBackground  Little is known about behavioural flexibility in children and adults with Angelman syndrome and whether people with this syndrome have more or less problems in being behaviourally flexible as compared with other people.Method  Behavioural flexibility scores were assessed in 129 individuals with Angelman syndrome using 11 items from the Behavioural Flexibility Rating Scale‐Revised (Green et al. 2007). Level of behavioural flexibility scores in individuals with Angelman syndrome (N = 129) was compared with that of people with non‐specific intellectual disability (ID) (N = 90), Down syndrome (N = 398) and Autism spectrum disorder (N = 235).Results  Comparative analyses show that individuals with Angelman syndrome were more flexible than those with non‐specific ID (P < 0.001) and those with Autism spectrum disorder (P < 0.01). There were no differences in behavioural flexibility scores between individuals with Angelman syndrome and those with Down syndrome (P = 0.94).Conclusion  It is concluded that individuals with Angelman syndrome are comparatively flexible in their behaviour.
Linear spatio‐temporal characterization of a UV microscope objective for nonlinear imaging and spectroscopy by using two‐dimensional spectral interferometry
Authors: AMIR W. , DURFEE C. G. , SCHAFER D. N. , GIBSON E. A. , KOST L. , PRZEKWAS E. , JIMENEZ R. , SQUIER J. A. 
Published: April 2008

SummaryTwo‐dimensional Fourier transform spectral interferometry is used to characterize the spatio‐temporal aberrations of a UV microscope objective. The spatial and temporal profiles of a 420 nm, 38 fs pulse at the focus of a 0.32 NA UV objective are then deduced using a wave propagation code incorporating the measured aberrations.
Quantifying immunogold labelling in transmission electron microscopy
Authors: D'AMICO F. , SKARMOUTSOU E. 
Published: April 2008

SummaryGold particles labelling on ultrathin sections is extensively used for antigen localization in transmission electron microscopy. In establishing absolute or relative counts in tissue sections, it would be expedient to use stereologically based unbiased estimates for quantitative results. Nowadays, quantitative immunoelectron microscopy has achieved good and satisfactory results to test whether the gold labelling follows a non‐random or a random pattern and then to draw statistical comparisons between cell subcompartments within a sample of cells or between experimental groups of cells. This brief informal review of literature focuses on the relative quantitative determinations of gold labelling of antigens as well as on the statistical distribution comparisons in transmission electron microscopy.
Spatial control of pa‐GFP photoactivation in living cells
Authors: TESTA I. , PARAZZOLI D. , BAROZZI S. , GARRÈ M. , FARETTA M. , DIASPRO A. 
Published: April 2008

SummaryPhotoactivatable green fluorescent protein (paGFP) exhibits peculiar photo‐physical properties making it an invaluable tool for protein/cell tracking in living cells/organisms. paGFP is normally excited in the violet range (405 nm), with an emission peak centred at 520 nm. Absorption cross‐section at 488 nm is low in the not‐activated form. However, when irradiated with high‐energy fluxes at 405 nm, the protein shows a dramatic change in its absorption spectra becoming efficiently excitable at 488 nm. Confocal microscopes allow to control activation in the focal plane. Unfortunately, irradiation extends to the entire illumination volume, making impracticable to limit the process in the 3D (three‐dimensional) space. In order to confine the process, we used two advanced intrinsically 3D confined optical methods, namely: total internal reflection fluorescence (TIRF) and two‐photon excitation fluorescence (2PE) microscopy. TIRF allows for spatially selected excitation of fluorescent molecules within a thin region at interfaces, i.e. cellular membranes. Optimization of the TIRF optical set‐up allowed us to demonstrate photoactivation of paGFP fused to different membrane localizing proteins. Exploitation of the penetration depth showed that activation is efficiently 3D confined even if limited at the interface. 2PE microscopy overcomes both the extended excitation volume of the confocal case and the TIRF constraint of operating at interfaces, providing optical confinement at any focal plane in the specimen within subfemtoliter volumes. The presented results emphasize how photoactivation by non‐linear excitation can provide a tool to increase contrast in widefield and confocal cellular imaging.
Characterization of the polarization sensitivity anisotropy of a near‐field probe using phase measurements
Authors: FISCHER H. , NESCI A. , LEVEQUE G. , MARTIN O.J.F. 
Published: April 2008

SummaryAmplitude and phase measurements of the near‐field generated by isolated subwavelength apertures in a gold film are presented. The near‐field distribution of such a structure is complex and the measured signal strongly depends on the electric field components effectively detected by the experimental setup. By comparing this signal with 3D vectorial calculations we are able to determine which electric field components are effectively measured. The sensitivity of the phase distribution is key to this measurement. The proposed characterization technique should prove extremely useful to calibrate a Scanning near‐field optical microscopy (SNOM) beforehand in order to retrieve quantitative information on the polarization of the field distribution under study.
Starch‐based backwards SHG for in situ MEFISTO pulse characterization in multiphoton microscopy
Authors: ANISHA THAYIL K. N. , GUALDA E. J. , PSILODIMITRAKOPOULOS S. , CORMACK I. G. , AMAT‐ROLDÁN I. , MATHEW M. , ARTIGAS D. , LOZA‐ALVAREZ P. 
Published: April 2008

SummaryWe report a simple methodology to provide complete pulse characterization at the sample plane of a two‐photon excited fluorescence (TPEF) microscope. This is achieved by using backward propagating second‐harmonic generation (SHG) from starch granules. Without any modification to the microscope, SHG‐autocorrelation traces were obtained by using a single starch granule that was placed alongside the biological specimen being imaged. A spectrally resolved SHG autocorrelation was acquired by placing a spectrometer at the output port of the microscope. Complete in situ pulse information is then directly retrieved in an analytical way using the measurement of electric filed by interferometric spectral trace observation (MEFISTO) technique.
Study of the structure of the air and blood capillaries of the gas exchange tissue of the avian lung by serial section three‐dimensional reconstruction
Authors: WOODWARD J. D. , MAINA J. N. 
Published: April 2008

SummaryWe have previously reconstructed the gas exchange tissue of the adult muscovy duck, Cairina moschata using a method of manually aligning sections and tracing the contours of the components of the gas exchange tissue. This reconstruction method demonstrated that the air capillaries are comprised of an expanded globular part interconnected by narrow air channels. The blood capillaries completely surround the air capillaries forming an anastomosing meshwork of short segments. However, the resulting reconstruction was limited in scope because of the laborious process of tracing the profiles of each component through the sequence of micrographs. We have now reconstructed a larger proportion of the exchange tissue by using a cross‐correlation based alignment strategy and have demonstrated that the staining intensity of each of the exchange tissue components is sufficiently different to allow them to be identified by simple filtering and thresholding. The resulting reconstructions sample a much larger proportion of the exchange tissue and demonstrate the heterogeneity of structures from different locations in the parabronchus. We have shown that a sheet‐flow‐type arrangement of blood capillaries surrounds the infundibulum; this represents an unexpected functional convergence with the arrangement of blood capillaries surrounding the mammalian alveoli. It is feasible, using this reconstruction strategy, to analyse the exchange tissue of a large number of avian species in order to determine structural correlates of function. The resulting reconstructions could be analysed in order to determine the basis of the functional efficiency and rigidity of the avian lung.