bluuebunny/crossref_metadata_2025_split huggingface dataset:
What is the function of hippocampal theta rhythm?—Linking behavioral data to phasic properties of field potential and unit recording data
Authors: Hasselmo Michael E. 
Published: September 2005

AbstractThe extensive physiological data on hippocampal theta rhythm provide an opportunity to evaluate hypotheses about the role of theta rhythm for hippocampal network function. Computational models based on these hypotheses help to link behavioral data with physiological measurements of different variables during theta rhythm. This paper reviews work on network models in which theta rhythm contributes to the following functions: (1) separating the dynamics of encoding and retrieval, (2) enhancing the context‐dependent retrieval of sequences, (3) buffering of novel information in entorhinal cortex (EC) for episodic encoding, and (4) timing interactions between prefrontal cortex and hippocampus for memory‐guided action selection. Modeling shows how these functional mechanisms are related to physiological data from the hippocampal formation, including (1) the phase relationships of synaptic currents during theta rhythm measured by current source density analysis of electroencephalographic data from region CA1 and dentate gyrus, (2) the timing of action potentials, including the theta phase precession of single place cells during running on a linear track, the context‐dependent changes in theta phase precession across trials on each day, and the context‐dependent firing properties of hippocampal neurons in spatial alternation (e.g., “splitter cells”), (3) the cholinergic regulation of sustained activity in entorhinal cortical neurons, and (4) the phasic timing of prefrontal cortical neurons relative to hippocampal theta rhythm. © 2005 Wiley‐Liss, Inc.
An analysis of the climate variability over the Mediterranean sea by means of the surface water vapour density
Authors: Schiano M. E. , Sparnocchia S. , Cappa C. , Bozzano R. 
Published: September 2005

AbstractMany studies suggest that the climate of the Mediterranean region is shifting toward a more tropical regime. In order to verify this supposed modification, an analysis is performed using the water vapour density at the sea surface. Previous experimental results in the region show that this parameter can evidence when the tropical features of the Mediterranean climate predominate. Compared to the other common indicators like the air temperature, it gives a more comprehensive picture of any possible variation by analysing the combined effect of two distinct parameters, the air temperature and the humidity, providing at the same time additional information on the surface marine thermal stratification. The work was performed using data from the European Centre for Medium‐range Weather Forecast (ECMWF) ERA‐40 project covering the period ranging from 1958 to 2001. Yearly averages and maxima of the water vapour density were obtained from the daily mean values. The number of days of the year in which these daily means were greater/equal to 15 gm−3, and the first and the last day of the year when they crossed this threshold were also evaluated. The investigation is carried out for the whole basin and its three main subbasins, namely, the western, the central and the eastern Mediterranean, separately. The results confirm that the occurrence of tropical features in the Mediterranean climate has been increasing in the last two decades, with a widening of the period affected by the condition and enhancement of the extreme values. This trend is detectable over the whole basin notwithstanding the very high interannual variability. The good agreement with the results obtained in other works where different variables or proxy data were used confirms that the surface water vapour density is a good indicator for detecting long term climate variability. Copyright © 2005 Royal Meteorological Society.
Palaeoclimatic reconstruction from Loch Lomond Readvance glaciers in the West Drumochter Hills, Scotland
Authors: Benn Douglas I. , Ballantyne Colin K. 
Published: September 2005

AbstractGeomorphological mapping in the West Drumochter Hills provides evidence of a readvance of locally nourished glaciers during the Loch Lomond (Younger Dryas) Stade, in the form of an icefield 67.7 km2 in area drained by outlet glaciers. The icefield limits accord broadly with those proposed by Sissons (1980) but all geomorphic, stratigraphic and sedimentological evidence conflicts with a recent proposal that the landforms in the area reflect southwestwards retreat of the last ice sheet. Up‐valley continuity of recessional moraines indicates that the ice remained active and close to climatic equilibrium during the earlier stages of glacier retreat, consistent with slow warming following the coldest part of the stade. The pattern of equilibrium line altitudes (ELAs) across the icefield is consistent with transfer of snow by westerly and southerly winds. The ELA of the reconstructed icefield as a whole is 622–629 m, although this figure is likely to be lower than the regional (climatic) ELA because the icefield probably received additional snow blown from adjacent plateau surfaces and slopes. Inclusion of potential snow‐blow areas in the ELA calculation yields a value of 648–656 m; the climatic ELA is therefore likely to have lain between 622 and 656 m. Mean June to August temperature at the ELA, based on chironomid assemblages at two sites, falls within the range 4.0 ± 0.7°C. Empirical relationships between temperature and precipitation at modern glacier ELAs indicate that mean annual precipitation (MAP) at the ELA was 1977 ± 464 mm, statistically indistinguishable from modern values. Comparison with precipitation values calculated for the Isle of Mull on the west coast suggest that the precipitation gradient across the Central Highlands of Scotland was steeper during the Loch Lomond Stade than at present, probably as the result of efficient scavenging of precipitation from westerly airflows by the West Highland Icefield. Copyright © 2005 John Wiley & Sons, Ltd.
Re‐interpretation of the Meikirch pollen record, Swiss Alpine Foreland, and implications for Middle Pleistocene chronostratigraphy
Authors: Preusser Frank , Drescher‐Schneider Ruth , Fiebig Markus , Schlüchter Christian 
Published: September 2005

AbstractThe Meikirch drilling site in the Swiss Midlands north of Bern is re‐interpreted using a combination of sedimentological logging, pollen analyses and luminescence dating. The sedimentary sequence comprises about 70 m of lacustrine deposits, overlain by about 39 m of coarse glacial outwash interpreted to represent at least two independent ice advances. Pollen analyses of the apparently complete limnic sequence reveal a basal late glacial period followed by three warm phases that are interrupted by two stadial periods (Meikirch complex). The warm periods were previously correlated with the Holsteinian and Eemian Interglacials. According to luminescence dating, and with consideration of evidence for Middle Pleistocene climate patterns at other central European sites, a correlation of the Meikirch complex with marine isotope stage (MIS) 7 is now proposed. If this correlation is correct, it implies the presence of three intervals with interglacial character during MIS 7. However, the late Middle Pleistocene vegetational features of the Meikirch complex show significant differences when compared with the pollen record from the Velay region, central France. Possible explanations for this discrepancy are distinct Middle Pleistocene patterns of atmospheric circulation over central Europe and a different distribution of vegetation refugia compared to the Eemian Interglacial and the Holocene. Copyright © 2005 John Wiley & Sons, Ltd.
Quaternary glaciation of the Bale Mountains, Ethiopia
Authors: Osmaston Henry A. , Mitchell Wishart A. , Osmaston J. A. Nigel 
Published: September 2005

AbstractCentral Ethiopia comprises a high plateau at 2000–3000 m, formed from Tertiary lava flows and bisected by the Eastern African Rift. Ten volcanic mountains rise to altitudes of just over 4000 m, but on only three has Quaternary glaciation been substantiated by published field observations. On the Bale Mountains (4400 m), a previous report based on limited evidence proposed an ice‐cap extending to 600 km2. Based on aerial photographs and ground surveys, this paper reports evidence of a more complex situation. A wide spread of large erratic boulders on the plateau records a central ice cap of 30 km2, though ice probably extended for a further 40 km2. Further north two groups of deeply incised and clearly glaciated valleys contain moraines and roches moutonnées (60 km2). On interfluves between them and on the open north slopes are moraines from an earlier stage of the same glaciation or from a distinct older event. Altogether about 180 km2 may have been glaciated. Cores dated by 14C from inside and outside the glaciated area suggest that at least the northern valley glaciers may date from the Last Glacial Maximum. Estimated equilibrium line altitudes for these glaciers and the ice‐cap are 3750–4230 m. Copyright © 2005 John Wiley & Sons, Ltd.
Holocene solifluction, climate variation and fire in a subarctic landscape at Pippokangas, Finnish Lapland, based on radiocarbon‐dated buried charcoal
Authors: Matthews John A. , Seppälä Matti , Dresser P. Quentin 
Published: September 2005

AbstractA large number of radiocarbon dates from charcoal layers buried beneath stacked solifluction lobes at Pippokangas, in the northern boreal zone of Finnish Lapland, are used to reconstruct a Holocene history of solifluction. Although the site is surrounded by Scots pine forest, the solifluction lobes occur on the lower slopes of a kettle hole, the microclimate of which prevents the growth of trees. Samples from the upslope end of charcoal layers have enabled the recognition of four synchronous phases of solifluction lobe initiation: 7400–6700, 4200–3400, 2600–2100 and 1500–500 cal. yr BP. Rates of lobe advance are shown to be lobe‐dependent and age‐dependent: initially, average rates were commonly 0.14–0.19 cm yr−1, later falling to 0.02–0.07 cm yr−1 or less as the lobes approached the bottom of the slope. The absence of charcoal prior to 8000 cal. yr BP, together with single IRSL and TL dates, indicate a relatively stable early Holocene landscape. The onset of solifluction around 7400 cal. yr BP. appears to have followed the immigration of pine around the site, which increased the frequency of forest fires. Phases of solifluction activity seem to have been triggered by millennial‐scale variations in effective moisture (the climatic hypothesis), rather than episodic burning of the surface vegetation cover (the geoecological hypothesis), although climate may also have affected fire frequency and severity. Copyright © 2005 John Wiley & Sons, Ltd.
Variation in the phytic acid content of soybeans and its effect on consistency of tofu made from soybean varieties with high protein content
Authors: Toda Kyoko , Takahashi Koji , Ono Tomotada , Kitamura Keisuke , Nakamura Yoshiyuki 
Published: September 2005

AbstractThe relationships of contents of phytic acid and protein to the breaking stress of tofu were examined using soybeans of three Japanese varieties with high protein content harvested in different locations from the years 2001 to 2003. The phytic acid content was more variable than protein content within different cultivating locations and years for the same variety and showed significant negative correlation to the breaking stress of tofu made with 0.25% MgCl2 for all the varieties (P < 0.001, r = −0.60). In particular, Sachiyutaka variety was characterized by the highest negative correlation between the breaking stress of tofu and the phytic acid content in soymilk (P < 0.001, r = −0.73). As MgCl2 concentration increased, the correlation between the phytic acid content and the breaking stress of tofu was reduced, and finally there was no significant correlation between them when the breaking stress reached a maximum at the particular MgCl2 concentration which is probably concerned with varietial characteristics of soybeans. These results support the idea that the variation in the content of phytic acid, which can act as a buffer against coagulation of soy protein, accounts for the fluctuation in consistency of tofu made with lower MgCl2 concentrations (ca. 0.25%) using soybeans of the same variety with different cultivating conditions. Copyright © 2005 Society of Chemical Industry
Effect of storage and heating on phytosterol concentrations in vegetable oils determined by GC/MS
Authors: Thanh Tran T , Vergnes Marie‐France , Kaloustian Jacques , El‐Moselhy Tarek F , Amiot‐Carlin Marie‐Jo , Portugal Henri 
Published: September 2005

AbstractPhytosterols can be of value in decreasing cardiovascular risk of coronary heart disease. β‐Sitosterol was the most abundant sterol in the three oils studied (sunflower, olive and ‘4 oil mixture’). The total phytosterol level was the highest in the ‘4 oil mixture’ compared with the other oils studied. Tests performed on the effect of aging (heating at 50 °C for several weeks and at 100 °C for 1 h) did not show any significant variation in the phytosterol content. In contrast, heating at 200 °C for 1 h led to a 50–60% decrease of phytosterol in the oils studied and in the standard solutions. Copyright © 2005 Society of Chemical Industry
Study on distribution pattern of stable carbon isotope ratio of Chinese honeys by isotope ratio mass spectrometry
Authors: Pang Guo‐Fang , Fan Chun‐Lin , Cao Yan‐Zhong , Zhang Jin‐Jie , Li Xue‐Min , Li Zeng‐Yin , Jia Guang‐Qun 
Published: September 2005

AbstractThe δ 13C values of 26 varieties of Chinese pure single‐flower honeys, 323 census samples of six varieties of single‐flower honeys and one multi‐flower honey as well as 20 888 commercial honey samples from 135 honey‐related enterprises in 25 provinces of China were analysed by stable carbon isotope ratio mass spectrometry between 1998 and 2004. It was found that the δ 13C values of different Chinese honeys fell within the ranges of values proposed by JW White. This shows that White's theory of the stable carbon isotope ratio of honeys is applicable to Chinese honeys and further demonstrates that the theory is universal to honeys from all over the world. The study also confirmed that the δ 13C values of honeys do not bear much relation to the environment in which the honey plants are grown, e.g. geographical area, water and soil, climate, etc., but do vary slightly with the honey plant species. Copyright © 2005 Society of Chemical Industry
Thermo‐ and pH‐Sensitivities of Thiosemicarbazone‐Incorporated, Fluorescent and Amphiphilic Poly(N‐isopropylacrylamide)
Authors: Li Cheng , Meng Ling‐Zhi , Lu Xiao‐Ju , Wu Zhao‐Qiang , Zhang Li‐Fen , He Yong‐Bing 
Published: September 2005

AbstractSummary: Novel hydrophobic comonomer (p‐methacrylamido)acetophenone thiosemicarbazone was synthesized and polymerized with N‐isopropylacrylamide to get a series of amphiphilic copolymers. The self‐aggregation behavior and thermo‐sensitive character of the (co)polymers were confirmed by TEM observation, fluorescence spectra, and cloud point measurement. Fluorescence emission of copolymer was significantly strengthened or switched off at an excitation wavelength of 320 nm upon the addition of acid or base, respectively. Thermo‐sensitivity, pH‐sensitivity, and pharmacologically versatile thiosemicarbazone groups were integrated into these novel fluorescent and amphiphilic copolymers, which will develop the novel applications of amphiphilic copolymer and environment‐responsive materials.Fluorescence intensity at 393 nm of polymer 2 in water at 18 °C excited at 320 nm upon addition of acid and base.imageFluorescence intensity at 393 nm of polymer 2 in water at 18 °C excited at 320 nm upon addition of acid and base.
Eburnamine derivatives and the brain
Authors: Vas Ádám , Gulyás Balázs 
Published: September 2005

AbstractThe Apocynaceae plant family contains a great number of so called eburnamine–vincamine alkaloids. Quite a few of these alkaloids exert varied pharmacological activities on the cell multiplication, cardiovascular system, and brain functions. Many derviatives were also synthesized to find pharmacologically active compunds better characterized and safer to be administered than the natural plant alkaloids themselves. We concentrate on the eburnamine structures with cerebral activities in this review. Vincamine, vinburnine, vindeburnol, apovincaminate, and vinpocetine (cis‐ethyl‐apovincaminate) all share modulatory effects on brain circulation and neuronal homeostasis, bear antihypoxic and neuroprotective potencies to various degrees. The most eminent compound of this class of alkaloids is vinpocetine. Since its introduction to the market as a neuroprotective agent many non clinical and clinical studies proved vinpocetine's effects on calmodulin dependent phosphodiesterase E1, on sodium, calcium channels, peripheral benzodiazepine receptor, and glutamate receptors as well as its clinical usefulness in the treatment of post‐ischaemic stroke disease states and various disorders of cerebrovascular origin. Lately, positron emission tomography studies proved that vinpocetine has a rapid uptake in the primate and human brain with a heterogenous distribution pattern (preference areas: thalamus, basal ganglia, and visual cortex) both after intravenous and oral administration. Vinpocetine exerts beneficial effects in cerebral glucose metabolism and regional cerebral blood flow in chronic post‐stroke patients. © 2005 Wiley Periodicals, Inc. Med Res Rev
Determination of the spatial structure of glutathione by residual dipolar coupling analysis
Authors: Klochkov Anton V. , Khairutdinov Bulat I. , Tagirov Murat S. , Klochkov Vladimir V. 
Published: September 2005

AbstractThe approach based on analysis of the residual 1H13C dipolar couplings in molecules partially aligned in a lyotropic liquid crystalline medium was used in the NMR investigation of the reduced glutathione (Glu–Cys–Gly; GSH) structure in a lyotropic medium (cetylpyridinium chloride–n‐hexanol). The spatial structure of GSH in solution was established on the basis of the experimental data for observed couplings only. Copyright © 2005 John Wiley & Sons, Ltd.
Ideal tetrafunctional amphiphilic PEG/PDMS conetworks by a dual‐purpose extender/crosslinker. II. Characterization and properties of water‐swollen membranes
Authors: Erdodi Gabor , Kennedy J. P. 
Published: September 2005

AbstractSelect characteristics and properties of a series of ideal tetrafunctional amphiphilic conetworks consisting of random poly(ethylene glycol) (PEG) and polydimethylsiloxane (PDMS) segments crosslinked by a novel dual‐purpose crosslinker/extender were determined. The overall composition of the conetworks was varied in the 16–40% PEG range, and membranes were prepared by polymerizing/crosslinking charges in molds. Membranes were characterized by equilibrium swelling (both in water and n‐heptane) and by determining their oxygen permeabilities and select mechanical properties. Swelling in water increases, whereas in heptane it decreases with increasing PEG content. Significant swelling in both solvents indicates bicontinuous (bipercolating) PEG and PDMS phases. Bicontinuity is reached with ∼13% PEG in the conetworks. The oxygen permeabilities of optically clear water‐swollen membranes containing 24, 32, and 40 wt % PEG are ∼350, ∼245 and ∼185 barrers, respectively, i.e., oxygen permeability decreases by increasing the hydrophilic constituent. These oxygen permeabilities are far superior to those of contemporary soft contact lenses. The tensile strengths and moduli of water‐swollen membranes decrease, while elongations increase, with increasing PEG content. Dry membranes exhibit first order transitions at −52 and ∼46 °C indicating phase‐separated crystalline PDMS and PEG domains, respectively. Both dry and water‐swollen membranes are optically clear, indicating the presence of PEG and PDMS domains with dimensions well below the wavelength of visible light. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 4965–4971, 2005
Ideal tetrafunctional amphiphilic PEG/PDMS conetworks by a dual‐purpose extender/crosslinker. I. Synthesis
Authors: Erdodi Gabor , Kennedy Joseph P. 
Published: September 2005

AbstractThe synthesis of a new type of amphiphilic conetwork (APCN) consisting of well‐defined hydrophilic poly(ethylene glycol) (PEG) and hydrophobic polydimethylsiloxane (PDMS) segments is described. The conetwork is ideal (the lengths of each PEG and PDMS chain segments, respectively, are identical) and tetrafunctional (exactly four chains emanate from each crosslink site). The synthesis of the conetworks was achieved by the use of a novel dual‐purpose extender/crosslinker Y (bis [(dimethylsilyl)oxy]‐[(etoxydimethylsilyl)oxy]phenylsilane, (SiPh(SiH)2OEt)), in two steps: (1) Synthesis of a new linear random multiblock copolymer (MBC) (AY)n(BY)m, where A is the hydrophilic PEG and B is the hydrophobic segment, and (2) Crosslinking the multiblocks by catalytic condensation of the SiOEt groups in the Y units. The extender/crosslinker fulfills two totally different functions: First, it extends two incompatible hydrophilic and hydrophobic prepolymers (PEG and PDMS) to a random MBC, and, subsequently, it cross‐links the multiblocks to the target APCN. The synthesis and characterization of the extender/crosslinker is also presented. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 4953–4964, 2005
Fabrication and microstructures of Si composite nanocone arrays
Authors: Meng X. M. , Shang N. G. , Lee C. S. , Bello I. , Lee S. T. 
Published: September 2005

AbstractMulti‐layer Si composite cones with nano‐scale diameter were fabricated by a simple ion sputtering method, and characterized with scanning electron microscopy (SEM), high‐resolution transmission electron microscopy (HRTEM), and electron energy loss spectroscopy. SEM observation showed that the as‐fabricated nanocone arrays on silicon substrates had a high density of 1010–1011 cm2, diameters of less than 70 nm, and heights of about 200 nm. Cross‐section HRTEM characterization revealed that the nanocones were composed of one‐, two‐ or three‐layer structures. The layer in these cones were identified to be pure Si, FeSi or 3C–SiC, and to have obvious orientation relationships. The formation mechanisms of the nanocones were discussed. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Formation of micrometer sized quasicrystals in slowly cooled Zr–Ti–Nb–Cu–Ni–Al alloys
Authors: Kühn U. , Eckert J. , Mattern N. , Schultz L. 
Published: September 2005

AbstractThe solidification behavior of copper mold cast Zr60Ti6Nb2Cu14Ni9Al9 and Zr60Ti2Nb6Cu14Ni9Al9 alloys has been investigated. The phase formation of the alloy with a ratio of Ti:Nb = 3:1 depends very sensitively on changes of the cooling conditions, exhibiting three competing phases: a glassy, an icosahedral quasicrystalline (i phase) and a crystalline phase, which are arranged very closely in the part of the sample with the highest cooling rate. Decreasing the cooling rate leads to a fully crystalline microstructure. In contrast, the alloy with a ratio of Ti:Nb = 1:3 forms predominantly an i phase and presents only a low volume fraction of a residual glassy phase at the interfaces of the quasicrystals. Besides a specific cooling rate a content of Cu + Ni + Al of about 32 at% and a content of Ti + Nb of about 8 at% is required for the formation of an as‐cast i phase in these Zr‐based alloys, because of a decrease of their glass‐forming ability linked with more pronounced icosahedral short‐range ordering in the melt. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)