bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of genetic variation in Kv1.3 on olfactory function
Authors: Guthoff Martina , Tschritter Otto , Berg Daniela , Liepelt Inga , Schulte Claudia , Machicao Fausto , Haering Hans‐Ulrich , Fritsche Andreas 
Published: June 2009

AbstractBackgroundOlfactory function is reduced in aged humans and diabetes mellitus patients. However, little is known about the pathogenic mechanisms leading to olfactory dysfunction. Recently, it has been shown that the voltage‐gated potassium channel Kv1.3 is regulated by insulin and is highly expressed in the olfactory bulb. Furthermore, the function of this channel is associated with olfaction in mice and with glucose metabolism in mice and men. We therefore hypothesized that a functionally relevant polymorphism in Kv1.3 might alter olfactory function.MethodsWe investigated a group of 94 healthy subjects (male: n = 58, female: n = 36) for olfactory function and genotyped them for rs2821557 in the human Kv1.3 gene. Olfactory function was tested using standardised sniffing sticks, and parameters of glucose metabolism were assessed.ResultsWe found a significant olfactory impairment in male homozygous carriers of the Kv1.3 polymorphism rs2821557 (recessive model, p = 0.018, adjusted for age) that could not be determined in female subjects due to the very small number of homozygous minor allele carriers (n = 1). In addition, we found a significant correlation of olfactory dysfunction with higher HbA1c and fasting plasma glucose (p = 0.004 and p = 0.001, both adjusted for age). We also found a loss of olfactory function with age (p = 0.006). Gender, body mass index and insulin sensitivity did not alter smelling function.ConclusionsThe presence of genetic variation in Kv1.3 is associated with decreased olfactory function in healthy subjects. As olfactory function, glucose metabolism and genetic variation in Kv1.3 seem to be associated, further studies are needed to clarify the underlying mechanisms. Copyright © 2009 John Wiley & Sons, Ltd.
Mono(aryloxido)Titanium(IV) Complexes and Their Application in the Selective Dimerization of Ethylene
Authors: Cazaux Jean‐Benoit , Braunstein Pierre , Magna Lionel , Saussine Lucien , Olivier‐Bourbigou Hélène 
Published: June 2009

AbstractWe report on the synthesis of mono(aryloxido)titanium(IV) complexes of general formula {Ti[O(o‐R)Ar]X3}, with X = OiPr, ArO = 2‐tert‐butyl‐4‐methylphenoxy and R = CMe3 (2a), CMe2Ph (2b) and CH2NMe2 (2c). Attempts to reach pure mono(aryloxido) complexes when R = CH2NMe(CH2Ph) (2d) or CH2N(CH2Ph)2 (2e) were unsuccessful. When R = CH2OMe, the analogous mononuclear complex was not obtained, and instead, a dinuclear complex [(2‐tert‐butyl‐4‐methyl‐6‐methoxymethylphenoxy) TiCl(OiPr)(μ2‐OiPr)2TiCl(OiPr)2] (3) was formed. Complexes 2b and 3 were characterized by single‐crystal X‐ray diffraction. The former contains a tetrahedrally coordinated TiIV centre, whereas in the latter the aryloxido ligand behaves as a chelating–bridging ligand between the two, chemically very different metal centres that form two face‐sharing octahedra. Different synthetic approaches starting from [Ti(OiPr)4] or [TiCl(OiPr)3] were evaluated and are discussed. The hemilabile behaviour of the aryloxido ligand resulting from reversible coordination of its side arm was studied by variable‐temperature 1H NMR spectroscopy for 2c (R = CH2NMe2). Complexes 2a–d were contacted with ethylene and AlEt3 as cocatalyst. When activated with AlEt3 (3 equiv.) at 20 bar and 60 °C, complex 2c exhibits interesting activity (2100 g/gTi/h) for the selective dimerization of ethylene to 1‐butene (92 % C4=; 99+% C4=1). Noticeable differences in catalyst activity were observed when the R group was modified. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Recent Applications of Acyclic (Diene)iron Complexes and (Dienyl)iron Cations in Organic Synthesis
Authors: Donaldson William A. , Chaudhury Subhabrata 
Published: June 2009

AbstractComplexation of (tricarbonyl)iron to an acyclic diene serves to protect the ligand against oxidation, reduction, and cycloaddition reactions, whereas the steric bulk of this adjunct serves to direct the approaches of reagents to unsaturated groups attached to the diene onto the face opposite to iron. Furthermore, the Fe(CO)3 moiety can serve to stabilize carbocation centers adjacent to the diene (i.e. pentadienyl‐iron cations). Recent applications of these reactivities to the synthesis of polyene‐, cyclopropane‐, cycloheptadiene‐, and cyclohexenone‐containing natural products or analogues are presented. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Probabilistic estimate of seismic response design values of RC frames
Authors: D'Ambrisi Angelo , Mezzi Marco 
Published: June 2009

AbstractProbabilistically controlled design values of the nonlinear seismic response of reinforced concrete frames are obtained using a method previously proposed by the authors. The method allows to calculate conservative design values characterized by a predefined non‐exceedance probability, using a limited number of spectrum‐fitting generated accelerograms. Herein the method is applied to elastic‐strain hardening single degree of freedom systems representative of RC framed structures and is then assessed with reference to four reinforced concrete model frames designed according to EC8. The frames are characterized by different natural periods and aspect ratios. The results, compared with those obtained applying current EC8 recommendations, show the effectiveness of the proposed method. EC8 provides for design values of the seismic response of a structure with a nonlinear behavior computed as the mean value of the responses to seven accelerograms or as the maximum value of the responses to three accelerograms. These two criteria lead to design values characterized by very different and uncontrolled non‐exceedance probability levels, while the proposed method allows the analyst to directly control the non‐exceedance probability level of the calculated design values. Copyright © 2009 John Wiley & Sons, Ltd.
Stability of central difference method for dynamic real‐time substructure testing
Authors: Wu Bin , Deng Lixia , Yang Xiandong 
Published: June 2009

AbstractThis paper studies the stability of the central difference method (CDM) for real‐time substructure test considering specimen mass. Because the standard CDM is implicit in terms of acceleration, to avoid iteration, an explicit acceleration formulation is assumed for its implementation in real‐time dynamic substructure testing. The analytical work shows that the stability of the algorithm decreases with increasing specimen mass if the experimental substructure is a pure inertia specimen. The algorithm becomes unstable however small the time integration interval is, when the mass of specimen equal or greater than that of its numerical counterpart. For the case of dynamic specimen, the algorithm is unstable when there is no damping in the whole test structure; a damping will make the algorithm stable conditionally. Part of the analytical results is validated through an actual test. Copyright © 2009 John Wiley & Sons, Ltd.
Wood distribution in neotropical forested headwater streams of La Selva, Costa Rica
Authors: Cadol Daniel , Wohl Ellen , Goode Jaime R. , Jaeger Kristin L. 
Published: June 2009

AbstractSurveys of wood along 30 forested headwater stream reaches in La Selva Biological Station in north‐eastern Costa Rica represent the first systematic data reported on wood loads in neotropical streams. For streams with drainage areas of 0·1–8·5 km2 and gradients of 0·2–8%, wood load ranged from 3 to 34·7 m3 wood/100 m channel and 41–612 m3 wood/ha channel. These values are within the range reported for temperate streams. The variables wood diameter/flow depth, stream power, the presence of backflooding, and channel width/depth are consistently selected as significant predictors by statistical models for wood load. These variables explain half to two‐thirds of the variability in wood load. These results, along with the spatial distribution of wood with respect to the thalweg, suggest that transport processes exert a greater influence on wood loads than recruitment processes. Wood appears to be more geomorphically effective in altering bed elevations in gravel‐bed reaches than in reaches with coarser or finer substrate. Copyright © 2009 John Wiley & Sons, Ltd.
Thermochronological data from Sudan in the frame of the denudational history of the Nubian Red Sea margin
Authors: Balestrieri M. L. , Abbate E. , Bigazzi G. , El Bedri Ali Omer 
Published: June 2009

AbstractLow‐temperature thermochronology provides information on the timing of rifting and denudation of passive margins, and the Red Sea with its well‐exposed, young rift margins is a suitable setting for its application. Here we present new apatite fission‐track (AFT) data from Sudan northern hinterland and Red Sea coastal areas. From the former region we obtained ages between 270 ± 2 Ma ad 253 ± 53 Ma, and from the coastal belt between 83 ± 8 Ma and 39 ± 7 Ma. These data prompted a review and comparison with low‐temperature thermochronological data from the whole Nubian Red Sea Margin, and a discussion on their implication in assessing the margin evolutionary style. AFT data are available for Egypt and Eritrea as well as apatite (U‐Th)/He (AHe) ages for two transects transversal to the margin in Eritrea. Both in Egypt and Eritrea AFT data record a cooling event at about 20–25 Ma (Early Miocene) and an earlier, more local, cooling event in Egypt at about 34 Ma (Early Oligocene). The thermal modeling of the Sudan samples provides an indication of a rapid cooling in Miocene times, but does not support nor rules out an Early Oligocene cooling phase. The re‐assessment of new and existing thermochronological data within the known geological framework of the Nubian and conjugate Arabian margins favours the hypothesis that early rifting stages were affecting the whole Gulf of Suez–Red Sea–Gulf of Aden system since the Oligocene. These precocious, more attenuated, phases were followed by major extension in Miocene times.As to the mode of margin evolution, AFT age patterns both in Egypt and Eritrea are incompatible with a downwarp model. The distribution of AHe ages across the Eritrean coastal plain suggests that there the escarpment was evolving predominantly by plateau degradation. Copyright © 2009 John Wiley & Sons, Ltd.
Seasonal patterns of suspended sediment transport in an abandoned farmland catchment in the Central Spanish Pyrenees
Authors: Lana‐Renault N. , Regüés D. 
Published: June 2009

AbstractThe suspended sediment response of a small catchment subjected to farmland abandonment and subsequent plant recolonization was studied in relation to its hydrological functioning. The analysis of data over a seven‐year period demonstrated that suspended sediment yield was greatly influenced by the occurrence of intense, low‐frequency events. Greater amounts of suspended sediment were exported during spring, when the catchment was hydrologically more active. Rainfall intensity and baseflow at the start of a flood event had a strong influence on the sediment response, suggesting that several hydrological processes were active within the catchment. SSC (suspended sediment concentration)‐Q hysteretic loop analysis at the event scale aided understanding of the sedimentological and hydrological behaviour of the catchment. During the study period the SSC‐Q loops showed a high degree of seasonality and two main patterns strongly related to catchment wetness were distinguished. When the catchment was dry (mainly during summer and the beginning of autumn) the predominant process was infiltration excess runoff over sparsely vegetated areas close to the main channel. Under these conditions, floods exhibited a counter‐clockwise hysteretic loop and were characterized by a small streamflow response, short duration and high SSC. Under wet conditions (mainly during winter and spring), saturation excess runoff was increasingly dominant over vegetated areas. Under these conditions, floods exhibited a clockwise hysteretic loop, and were characterized by a larger streamflow response, longer duration and higher suspended sediment yield. The lower SSC during the falling stage of the hydrograph is likely to be due to dilution effects related to the contribution of clean water resulting from enlargement of the saturated areas, together with an increase in the baseflow discharge. Copyright © 2009 John Wiley & Sons, Ltd.
Development of an expert system for the interpretation of displacement monitoring data
Authors: Großauer Karl , Schubert Wulf 
Published: June 2009

AbstractDisplacement monitoring has been common practice during tunnel excavation for many decades. The results are usually used to assess the stabilisation process and to adapt excavation and support to the actual conditions. Although monitoring is done routinely on practically all sites, no consistent collection of case histories has yet been established, so the experience gained on completed projects is rarely available for new projects. To better utilise this previous experience, an expert system for the evaluation and interpretation of displacement monitoring data is currently under development. The main component of the system is an expert knowledge base containing normal displacement behaviour for a wide range of geotechnical conditions. Methods required for the identification of such normal displacement situations as well as for clear description of the displacement characteristics have been developed and will be outlined. The check whether the actually observed displacements are normal will be done by means of a comparison with a real displacement scenario from the database. In case a significant deviation is identified, the actual displacement trends will be compared to reference trends characteristic for changing ground conditions and the most probable situation determined. If the degree of correlation is low, then it is very probable that the actual displacements show abnormal behaviour.
Neural correlates of pre‐attentive processing of pattern deviance in professional musicians
Authors: Habermeyer Benedikt , Herdener Marcus , Esposito Fabrizio , Hilti Caroline C. , Klarhöfer Markus , di Salle Francesco , Wetzel Stephan , Scheffler Klaus , Cattapan‐Ludewig Katja , Seifritz Erich 
Published: June 2009

AbstractPre‐attentive registration of aberrations in predictable sound patterns is attributed to the temporal cortex. However, electrophysiology suggests that frontal areas become more important when deviance complexity increases. To play an instrument in an ensemble, professional musicians have to rely on the ability to detect even slight deviances from expected musical patterns and therefore have highly trained aural skills. Here, we aimed to identify the neural correlates of experience‐driven plasticity related to the processing of complex sound features. We used functional magnetic resonance imaging in combination with an event‐related oddball paradigm and compared brain activity in professional musicians and non‐musicians during pre‐attentive processing of melodic contour variations. The melodic pattern consisted of a sequence of five tones each lasting 50 ms interrupted by silent interstimulus intervals of 50 ms. Compared to non‐musicians, the professional musicians showed enhanced activity in the left middle and superior temporal gyri, the left inferior frontal gyrus and in the right ventromedial prefrontal cortex in response to pattern deviation. This differential brain activity pattern was correlated with behaviorally tested musical aptitude. Our results thus support an experience‐related role of the left temporal cortex in fast melodic contour processing and suggest involvement of the prefrontal cortex. Hum Brain Mapp, 2009. © 2009 Wiley‐Liss, Inc.
Endogenous cannabinoid signaling is required for voluntary exercise‐induced enhancement of progenitor cell proliferation in the hippocampus
Authors: Hill Matthew N. , Titterness Andrea K. , Morrish Anna C. , Carrier Erica J. , Lee Tiffany T.‐Y. , Gil‐Mohapel Joana , Gorzalka Boris B. , Hillard Cecilia J. , Christie Brian R. 
Published: June 2009

AbstractVoluntary exercise and endogenous cannabinoid activity have independently been shown to regulate hippocampal plasticity. The aim of the current study was to determine whether the endocannabinoid system is regulated by voluntary exercise and if these changes contribute to exercise‐induced enhancement of cell proliferation. In Experiment 1, 8 days of free access to a running wheel increased the agonist binding site density of the cannabinoid CB1 receptor; CB1 receptor‐mediated GTPγS binding; and the tissue content of the endocannabinoid anandamide in the hippocampus but not in the prefrontal cortex. In Experiment 2, the CB1 receptor antagonist AM251 (1 mg kg−1) was administered daily to animals given free access to a running wheel for 8 days, after which cell proliferation in the hippocampus was examined through immunohistochemical analysis of the cell cycle protein Ki‐67. Voluntary exercise increased proliferation of progenitor cells, as evidenced by the increase in the number of Ki‐67 positive cells in the granule cell layer of the dentate gyrus (DG) in the hippocampus. However, this effect was abrogated by concurrent treatment with AM251, indicating that the increase in endocannabinoid signaling in the hippocampus is required for the exercise‐induced increase in cell proliferation. These data demonstrate that the endocannabinoid system in the hippocampus is sensitive to environmental change and suggest that it is a mediator of experience‐induced plasticity. © 2009 Wiley‐Liss, Inc.
Dose‐dependent long‐term effects of Tat in the rat hippocampal formation: A design‐based stereological study
Authors: Fitting Sylvia , Booze Rosemarie M. , Hasselrot Ulla , Mactutus Charles F. 
Published: June 2009

AbstractThe human immunodeficiency virus type 1 (HIV‐1) protein transactivator of transcription (Tat) is believed to play a critical role in mediating central nervous system (CNS) pathology in pediatric HIV‐1 infection. Long‐term neurotoxicity was investigated in a design‐based stereology study following intrahippocampal injection of Tat on postnatal day (P)10, a time period that approximates the peak in the rats' rate of brain growth and mimics clinical HIV‐1 CNS infection at labor/delivery. The goal was to examine the impact of P10 intrahippocampal Tat injection on the anatomy of the adult hippocampus (5 month) to gain a better understanding about how timing of infection influences the rate of progression of pediatric HIV‐1 infection [cf. Fitting et al. (2008a) Hippocampus 18:135–147]. Male P10 Sprague‐Dawley rats were bilaterally injected with vehicle or one of three different doses of Tat (5, 25, or 50 μg). Unbiased stereological estimates were used to quantify total neuron number (Nissl stain) in five major subregions of the rat hippocampus: granular layer (GL), hilus of the dentate gyrus (DGH), cornu ammonis fields (CA)2/3, CA1, and subiculum (SUB). Glial cells (astrocytes and oligodendrocytes) were quantified in the DGH and SUB. No significant reduction of neuron number was noted for any of the five hippocampal subregions, in contrast to the very prominent reductions reported when Tat was administered on P1 [Fitting et al. (2008a) Hippocampus 18:135–147]. However, for glial cells, the number of astrocytes in the DGH and SUB as well as the number of oligodendrocytes in the DGH were linear dose dependently increased as a function of dose of Tat. In conjunction with previous stereological research [Fitting et al., (2008a) Hippocampus 18:135–147], the present data suggest that variability in the progression of pediatric HIV/acquired immunodeficiency syndrome (AIDS) may be better understood with the knowledge of the factor of timing of HIV‐1 CNS infection. © 2009 Wiley‐Liss, Inc.
Distinct trafficking and expression mechanisms underlie LTP and LTD of NMDA receptor‐mediated synaptic responses
Authors: Peng Yi , Zhao Jiang , Gu Qin‐Hua , Chen Rong‐Qing , Xu Zhuo , Yan Jing‐Zhi , Wang Shan‐Hui , Liu Su‐Yi , Chen Zheng , Lu Wei 
Published: June 2009

AbstractAlthough an increasing number of studies have demonstrated the plasticity of NMDA receptor‐mediated synaptic transmission, little is known about the molecular mechanisms that underlie this neurologically important process. In a study of NMDAR‐mediated synaptic responses in hippocampal Schaffer‐CA1 synapses whose AMPA receptor (AMPAR) activity is totally blocked, we uncovered differences between the trafficking mechanisms that underlie the long‐term potentiation (LTP) and long‐term depression (LTD) that can be induced in these cells under these conditions. The LTP‐producing protocol failed to induce a change in the amplitude of NMDAR‐mediated postsynaptic currents (NMDAR EPSCs) in the first 5–10 min, but induced gradual enhancement of NMDAR EPSCs thereafter that soon reached a stable magnitude. This “slow” LTP of NMDAR EPSCs (LTPNMDA) was blocked by inhibiting exocytosis or actin polymerization in postsynaptic cells. By contrast, LTD of NMDAR EPSCs (LTDNMDA) was immediately inducible, and, although it was blocked by the actin stabilizer, it was unaffected by exocytosis or endocytosis inhibitors. Furthermore, concomitant changes in the decay time of NMDAR EPSCs suggested that differential switches in NR2 subunit composition accompanied LTPNMDA and LTDNMDA, and these changes were blocked by the calcium buffer BAPTA or an mGluR antagonist. Our results suggest that LTPNMDA and LTDNMDA utilize different NMDAR trafficking pathways and express different ratios of NMDAR subunits on the postsynaptic surface. © 2009 Wiley‐Liss, Inc.
Chronic social stress during adolescence induces cognitive impairment in aged mice
Authors: Sterlemann Vera , Rammes Gerhard , Wolf Miriam , Liebl Claudia , Ganea Karin , Müller Marianne B. , Schmidt Mathias V. 
Published: June 2009

AbstractAge‐related cognitive decline is one of the major aspects that impede successful aging in humans. Environmental factors, such as chronic stress, can accelerate or aggravate cognitive deficits during aging. While there is abundant evidence that chronic stress directly affects cognitive performance, the lasting consequences of stress exposures during vulnerable developmental time windows are largely unknown. This is especially true for the adolescent period, which is critical in terms of physical, sexual, and behavioral maturation. Here we used chronic social stress during adolescence in male mice and investigated the consequences of this treatment on cognitive performance during aging. We observed a substantial impairment of spatial memory, but not other memory domains, 12 months after the end of the stress period. This hippocampus‐dependent cognitive dysfunction was supported by concomitant impairment in LTP induction in CA1 neurons in 15‐month‐old animals. Further, we observed a decrease of hippocampal BDNF mRNA and synaptophysin immunoreactivity, suggesting plasticity and structural alterations in formerly stressed mice. Finally, we identified expression changes of specific neurotransmitter subunits critically involved in learning and memory, specifically the NMDA receptor subunit NR2B. Taken together, our results identify possible molecular mechanisms underlying cognitive impairment during aging, demonstrating the detrimental impact of stress during adolescence on hippocampus‐dependent cognitive function in aged mice. © 2009 Wiley‐Liss, Inc.