bluuebunny/crossref_metadata_2025 huggingface dataset:
Adsorption of hydrogen molecules on the platinum-doped boron nitride nanotubes
Authors: Wu Xiaojun , Yang J. L. , Zeng X. C.
Published: July 2006

Adsorption of hydrogen molecules on platinum-doped single-walled zigzag (8,0) boron nitride (BN) nanotube is investigated using the density-functional theory. The Pt atom tends to occupy the axial bridge site of the BN tube with the highest binding energy of −0.91eV. Upon Pt doping, several occupied and unoccupied impurity states are induced, which reduces the band gap of the pristine BN nanotube. Upon hydrogen adsorption on Pt-doped BN nanotube, the first hydrogen molecule can be chemically adsorbed on the Pt-doped BN nanotube without crossing any energy barrier, whereas the second hydrogen molecule has to overcome a small energy barrier of 0.019eV. At least up to two hydrogen molecules can be chemically adsorbed on a single Pt atom supported by the BN nanotube, with the average adsorption energy of −0.365eV. Upon hydrogen adsorption on a Pt-dimer-doped BN nanotube, the formation of the Pt dimer not only weakens the interaction between the Pt cluster and the BN nanotube but also reduces the average adsorption energy of hydrogen molecules. These calculation results can be useful in the assessment of metal-doped BN nanotubes as potential hydrogen storage media.
An accurate ab initio potential energy surface and calculated spectroscopic constants for BeH2, BeD2, and BeHD
Authors: Li Hui , Le Roy Robert J.
Published: July 2006

A three-dimensional potential energy surface for the ground electronic state of BeH2 has been determined by three-dimensional spline interpolation over 6864 symmetry-unique ab initio points calculated at the icMRCI/aug-cc-pV5Z level and corrected for core-electron correlation computed at the MR-ACPF/cc-pCV5Z level. Calculated spectroscopic constants of BeH2 and BeD2 are in excellent agreement with recent experimental results: for 11 bands of BeH2 and 5 bands of BeD2 the root mean square (rms) band origin discrepancies were only 0.15(±0.09) and 0.46(±0.19)cm−1, respectively, and the rms relative discrepancies in the inertial rotational constants (B[v]) were only 0.028% and 0.023%, respectively. Spectral constants for BeHD were predicted using the same potential surface. The effect of different interpolation methods on predicted potential function values and on the calculated level energies and spectroscopic constants has been examined.
Quantum equations for vibrational dynamics on metal surfaces
Authors: Krishna Vinod
Published: July 2006

A first principles treatment of the vibrational dynamics of molecular chemisorbates on metal surfaces is presented. It is shown that the mean field quantum evolution of the vibrational position operator is determined by a quantum Langevin equation with an electronic friction. In the mean field limit, the quantum noise and friction are related by the quantum fluctuation-dissipation theorem. The classical limit of this model is shown to agree with previously proposed models. A criterion is presented to describe the validity of the weak-coupling approximation and equations of motion for the dynamics in the presence of strong nonadiabatic coupling to electron-hole pairs are presented.
Oxygen diffusion and reactions in Hf-based dielectrics
Authors: Goncharova L. V. , Dalponte M. , Starodub D. G. , Gustafsson T. , Garfunkel E. , Lysaght P. S. , Foran B. , Barnett J. , Bersuker G.
Published: July 2006

Oxygen transport in and reactions with thin hafnium oxide and hafnium silicate films have been investigated using medium energy ion scattering in combination with O218 isotopic tracing methods. Postgrowth oxidation of Hf-based films in an O218 atmosphere at 490–950°C results in O exchange in the film. The exchange rate is faster for pure hafnium oxides than for silicates. The amount of exchanged oxygen increases with temperature and is suppressed by the SiO2 component. Films annealed prior to oxygen isotope exposure show complex incorporation behavior, which may be attributed to grain boundary defects, and SiO2 phase segregation.
Unified semiclassical theory for the two-state system: An analytical solution for general nonadiabatic tunneling
Authors: Zhu Chaoyuan , Lin Sheng Hsien
Published: July 2006

Unified semiclasical solution for general nonadiabatic tunneling between two adiabatic potential energy surfaces is established by employing unified semiclassical solution for pure nonadiabatic transition [C. Zhu, J. Chem. Phys. 105, 4159 (1996)] with the certain symmetry transformation. This symmetry comes from a detailed analysis of the reduced scattering matrix for Landau-Zener type of crossing as a special case of nonadiabatic transition and nonadiabatic tunneling. Traditional classification of crossing and noncrossing types of nonadiabatic transition can be quantitatively defined by the rotation angle of adiabatic-to-diabatic transformation, and this rotational angle enters the analytical solution for general nonadiabatic tunneling. The certain two-state exponential potential models are employed for numerical tests, and the calculations from the present general nonadiabatic tunneling formula are demonstrated in very good agreement with the results from exact quantum mechanical calculations. The present general nonadiabatic tunneling formula can be incorporated with various mixed quantum-classical methods for modeling electronically nonadiabatic processes in photochemistry.
Determination of active sites for H atom rearrangement in dissociative ionization of ethanol
Authors: Sharma Vandana , Bapat B.
Published: July 2006

In an electron impact dissociative ionization experiment on C2H5OH, the formation of molecular ions requiring rearrangement of H atoms has been studied using a momentum spectrometer. H3+, H2+, HOH+, and H2OH+ observed in the experiment are molecular ions of this type. By comparing the mass spectrum of C2H5OH with that of its isotopomer C2H5OD, we determine the proportions of H–bond rearrangements involving carbon and oxygen sites. We find that the formation of H3+ due to the breaking of the O–H bond and rearrangement of the H atoms on the CH2 site is about 2.5 times as likely as its formation involving atoms from the CH3 site alone. No such difference is seen in case of the H2+ ion. The role of the O–H bond in formation of all observed ions has been assessed. Kinetic energy distributions of the molecular ions suggest that two or three electronically excited states contribute to their formation.
Nanoengineering mechanically robust aerogels via control of foam morphology
Authors: Kucheyev S. O. , Baumann T. F. , Cox C. A. , Wang Y. M. , Satcher J. H. , Hamza A. V. , Bradby J. E.
Published: July 2006

Potential of aerogels for technological applications is often limited by their poor mechanical properties. Here, we demonstrate that alumina aerogel monoliths with excellent mechanical properties can be made by controlling the crystallographic phase, shape, and size of nanoligaments. In particular, we show that thermal processing of aerogels with a morphology of interconnected nanoleaflets causes dehydration and associated curling of the nanoleaflets, resulting in a dramatic improvement of mechanical properties. This study shows an effective way to control mechanical properties of the nanoporous solids that can be synthesized with ligaments having a quasi-two-dimensional shape, such as platelets, ribbons, or leaflets.
Mode tuning of quantum cascade lasers through optical processing of chalcogenide glass claddings
Authors: Song Shanshan , Howard Scott S. , Liu Zhijun , Dirisu Afusat O. , Gmachl Claire F. , Arnold Craig B.
Published: July 2006

In this letter, we demonstrate a method of tuning quantum cascade (QC) lasers by modifying the optical properties of an overlying cladding material. An amorphous chalcogenide cladding layer is deposited through a low temperature, solvent-casting technique that is compatible with current QC laser fabrication and operation. Above band gap illumination (λ<530nm) of this cladding causes a permanent change in its index of refraction leading to a change of the modal refractive index and a corresponding modal shift in the laser. Combined with deep-etched distributed Bragg gratings, a tuning of over 30nm is obtained at an operating wavelength of 7.9μm for constant current and temperature.
Propagation of a partially coherent twisted anisotropic Gaussian Schell-model beam in a turbulent atmosphere
Authors: Cai Yangjian , He Sailing
Published: July 2006

Analytical formulas are derived for the propagation of a partially coherent twisted anisotropic Gaussian Schell-model (TAGSM) beam in a turbulent atmosphere. Propagation properties of a TAGSM beam in a turbulent atmosphere are investigated in detail. It is found that a TAGSM beam will become a circular beam in a turbulent atmosphere, and low coherence and larger twist have an effect of anticircularization of the beam spot. The beam spot spreads more rapidly for lower coherence, larger twist, or stronger turbulence.
Characterization of mycobacterial virulence genes through genetic interaction mapping
Authors: Joshi Swati M. , Pandey Amit K. , Capite Nicole , Fortune Sarah M. , Rubin Eric J. , Sassetti Christopher M.
Published: July 2006

We have previously shown that ≈5% of the genes encoded by the genome of
Mycobacterium tuberculosis
are specifically required for the growth or survival of this bacterium during infection. This corresponds to hundreds of genes, most of which have no identifiable function. As a unique approach to characterize these genes, we developed a method to rapidly delineate functional pathways by identifying mutations that modify each other’s phenotype, i.e., “genetic interactions”. Using this method, we have defined a complex set of interactions between virulence genes in this pathogen, and find that the products of unlinked genes associate to form multisubunit transporters that are required for bacterial survival in the host. These findings implicate a previously undescribed family of transport systems in the pathogenesis of tuberculosis, and identify genes that are likely to function in the metabolism of their substrates. This method can be readily applied to other organisms at either the single pathway level, as described here, or at the system level to define quantitative genetic interaction networks.
Establishing a baseline for the monitoring of medicines availability for children in the UK: 1998–2002
Authors: Balakrishnan Komathi , Tordoff June , Norris Pauline , Reith David
Published: July 2006

Aim

To determine changes in the availability, in terms of licensing and formulations, of medicines for children in the UK between 1998 and 2002.

Methods

Using the Association of British Pharmaceutical Industry (ABPI) Compendium of Data Sheets and Summaries of Product Characteristics (SPC) 1998 and the Medicines Compendium 2002, licensed medicines available in the UK in the calendar years 1998 and 2002 were examined.

Results

In 1998, 61% of chemical entities/fixed‐dose combinations were licensed in some form for children compared with 64% in 2002. Of the chemical entities/fixed‐dose combinations with oral formulations, 250 (33%) in 1998 had an oral formulation suitable for use by children and in 2002 there were 284 (34%). Of the 129 new chemical entities registered in the UK between 1998 and 2002, only 30 (23%) were licensed for under the age of 12 years and 19 (15%) for the neonatal age group. A total of 480 medicines licensed for children were withdrawn from marketing but only cisapride and primidone had no generic or therapeutic alternatives.

Conclusion

Although there was improvement in the availability of medicines for children in the UK over the 5‐year period (1998–2002), considerable inequities still existed between children and adults.
Order and disorder in the river continuum: the contribution of continuity and connectivity to floodplain meadow biodiversity
Authors: Looy Kris Van , Honnay Olivier , Pedroli Bas , Muller Serge
Published: July 2006

Aim  Aspects of connectivity and continuity operating in the River Meuse were analysed for their contribution to the biodiversity of the floodplain. From this analysis of the diversity and composition of the meadow communities, we aimed to derive effective biodiversity conservation strategies.

Location  The River Meuse is one of the larger rivers in the European Western Plains ecoregion. The alluvial plains of the river have a long history of cultivation, and for these plains the floodplain meadow vegetation is a highly appreciated and valuable nature conservation asset.

Method  We sampled floodplain meadows from 400 km of the six geomorphic reaches of the middle to lower course of the River Meuse. For each, 50 vascular plant relevés were recorded, representing the spectrum of floodplain meadow communities of that reach. Beta diversity was calculated to quantify similarity in species pools between the reaches. A dissimilarity formula was used to determine the turnover between the reaches, and these dissimilarities were compared with a Mantel test to detect whether species composition of the floodplain meadows exhibited connectivity and continuity between the reaches. Species richness for the floodplain vegetation data of the reaches was compared with data for riparian invertebrate communities. The vegetation data sets were ordinated using detrended correspondence analysis (DCA) to reveal patterns in the floodplain meadow species composition, and the DCA axes were related to plant functional groups and population strategies. The axis scores of the species and plots were linked to river and plant species traits.

Results  We did not observe an overall continuity trend in similarity, nor one in diversity in a downstream direction. Lateral connectivity was highlighted by the dissimilarity between the reaches and in the influxes of species from adjacent ecoregions. The DCA ordination showed statistically significant separations between reaches and between the plant functional groups. The second DCA axis related to the longitudinal gradient of the river, whereas the first axis showed stronger correlations with river and plant species traits. We termed this axis the ‘disorder axis’. Plant invaders and avoiders are located at the left side of the disorder axis, whereas the true river‐adapted categories of resisters and endurers are at the right extremity. Contributions to the disorder were identified in terms of connectivity with adjacent ecoregions and the physical disturbance regime of natural and anthropogenic perturbations, resulting in community changes between the reaches.

Main conclusions  We concluded that a single overall strategy for biodiversity conservation of the river or its floodplains is not feasible. Strategies can, however, be derived for separate river reaches based on functional groups in the communities, the disorder characteristics of the reach, and the influence of surrounding ecoregions.
The prevalence of vitamin D inadequacy amongst women with osteoporosis: an international epidemiological investigation
Authors: LIPS P. , HOSKING D. , LIPPUNER K. , NORQUIST J. M. , WEHREN L. , MAALOUF G. , RAGI‐EIS S. , CHANDLER J.
Published: July 2006

Introduction.  Vitamin D is essential for calcium metabolism as well as for fracture prevention, and a recent review suggested that the optimal serum 25(OH)D lies in the region of 50–80 nmol L−1 (20–32 ng mL−1). A high prevalence of inadequacy has been reported in many studies but the prevalence of inadequacy amongst women with osteoporosis in different regions of the world has not been well characterized.

Setting and subjects.  A multinational study of 18 countries at various latitudes (range 64N–38S) was conducted in 2004 and 2005 to determine the average levels of serum 25(OH)D and the prevalence of vitamin D inadequacy. A total of 2606 postmenopausal women with osteoporosis (low bone mineral density, history of fragility fracture) seeking routine medical care were enrolled and serum 25(OH)D levels were measured at a single laboratory visit.

Results.  Mean serum 25(OH)D level was 26.8 ng mL−1 (SE 0.3) and ranged from 7 to 243 ng mL−1. Regional mean values were highest in Latin America (29.6 ng mL−1, SE 0.6) and lowest in the Middle East (20.4 ng mL−1, SE 0.5). Overall, 64% of women had serum levels <30 ng mL−1. Serum parathyroid hormone reached a nadir at serum 25(OH)D levels >35 ng mL−1. In nonequatorial countries, women recruited during the winter months had somewhat lower serum 25(OH)D levels than those recruited during the summer months in some, but not all, countries.

Conclusions.  Low levels of serum 25(OH)D are common amongst women with osteoporosis. The results underscore the value of assuring vitamin D adequacy in these women.
Apolipoprotein B as a long‐term predictor of mortality in type 1 diabetes mellitus: a 15‐year follow up
Authors: STETTLER C. , SUTER Y. , ALLEMANN S. , ZWAHLEN M. , CHRIST E. R. , DIEM P.
Published: July 2006

Objectives.  To evaluate the association of apolipoprotein B (apo B) with mortality due to all causes, to cardiac disease and to ischaemic heart disease (IHD) in subjects with type 1 diabetes mellitus.

Subjects.  165 subjects with type 1 diabetes included in the Swiss Cohort of the WHO Multinational Study of Vascular Disease in Diabetes were followed for 14.7 ± 0.45 years.

Methods.  Causes of death were obtained from death certificates, hospital records and postmortem reports. Using a parametric proportional hazards model the association of apo B with mortality rates was assessed by time‐to‐event analysis, including the absolute cumulative mortality risk over time for various apo B levels at baseline.

Results.  Apo B was positively associated with all‐cause mortality [hazard ratio (HR) 2.65 per g L−1 increase of apo B, 95% CI: 1.11–6.36, P = 0.029], cardiac mortality (HR 11.64, 1.03–131.11, P = 0.047) and IHD mortality (HR 9.36, 1.26–69.66, P = 0.029). An apo B ≥0.96 g L−1 translated into a duplication of overall mortality hazard (HR 1.93, 1.00–3.72, P = 0.050), and a sevenfold increase of mortality because of cardiac disease or IHD (HR 7.44, 1.44–38.42, P = 0.017 and HR 7.38, 0.78–69.82, P = 0.081). A baseline apo B of 1.5 g L−1 predicted an absolute cumulative risk to die over the next 10 years of 12.1% (5.2–31.7) for male and of 10.4% (4.7–26.1) for female subjects whereas risks were 6.3% (1.8–21.4) and 5.4% (0.8–15.8) for an apo B of 0.8 g L−1.

Conclusion.  Apo B is consistently associated with an increased mortality in type 1 diabetes.
Glutathione peroxidase‐like protein of Synechocystis PCC 6803 confers tolerance to oxidative and environmental stresses in transgenic Arabidopsis
Authors: Gaber Ahmed , Yoshimura Kazuya , Yamamoto Takashi , Yabuta Yukinori , Takeda Toru , Miyasaka Hitoshi , Nakano Yoshihisa , Shigeoka Shigeru
Published: July 2006

Glutathione peroxidase (GPX)‐like proteins (GPX‐1 and GPX‐2) of Synechocystis PCC 6803 (S. PCC 6803) reduce unsaturated fatty acid hydroperoxides using NADPH, but not reduced glutathione (GSH), as an electron donor. Here, we generated transgenic Arabidopsis plants overexpressing S. PCC 6803 GPX‐2 in the cytosol (AcGPX2) or chloroplasts (ApGPX2). The activities toward α‐linolenic acid hydroperoxide in ApGPX2 and AcGPX2 plants were 6.5–11.5 and 8.2–16.3 nmol min−1 mg protein−1, respectively, while no activity (<0.1 nmol min−1 mg protein−1) was detected in the wild‐type plants. Both transgenic lines (AcGPX2 and ApGPX2) showed enhanced tolerance to oxidative damage caused by treatment with H2O2 (10 mM), Fe ions (200 μM) or methylviologen (50 μM) and environmental stress conditions, such as chilling with high light intensity (4°C, 1000 μmol photons m−2 s−1), high salinity (100 mM NaCl) or drought. The degree of tolerance of the transgenic plants to all types of stress was correlated with the levels of lipid peroxide suppressed by the overexpression of S. PCC 6803 GPX‐2. Under conditions of oxidative stress due to the H2O2 treatment, the NADPH/(NADP++ NADPH) ratio in the transgenic plants was lower than that in the wild‐type plants. The data reported here indicate that the expression of S. PCC 6803 GPX‐2 contributes to the reduction in unsaturated fatty acid hydroperoxides using NADPH in situ under stress conditions in the transgenic plants.
Substantial changes in the genetic basis of tadpole morphology of Rana lessonae in the presence of predators
Authors: Kraft P. G. , Wilson R. S. , Franklin C. E. , Blows M. W.
Published: July 2006

Predator-induced morphological plasticity is a model system for investigating phenotypic plasticity in an ecological context. We investigated the genetic basis of the predator-induced plasticity in Rana lessonae by determining the pattern of genetic covariation of three morphological traits that were found to be induced in a predatory environment. Body size decreased and tail dimensions increased when reared in the presence of preying dragonfly larvae. Genetic variance in body size increased by almost an order of magnitude in the predator environment, and the first genetic principal component was found to be highly significantly different between the two environments. The across environment genetic correlation for body size was significantly below 1 indicating that different genes contributed to this trait in the two environments. Body size may therefore be able to respond to selection independently in the two environments to some extent.
Shedding of Porcine Circovirus into Colostrum of Sows
Authors: Shibata I. , Okuda Y. , Kitajima K. , Asai T.
Published: July 2006

The purpose of the present study was to investigate porcine circovirus (PCV) shedding into the milk of sows. Colostrum was collected from 33 sows. PCV1 was isolated from four of 33 milk whey samples. PCV1 DNA was detected by polymerase chain reaction in three of these samples and in three of 10 milk cell samples. PCV2 was also isolated and detected from every single milk whey sample. These results showed that PCV1 and PCV2 were shed into the milk of sows and suggest that PCV can be transmitted to offspring by an oral route through milk.
Canine Distemper Virus Induces Apoptosis Through Caspase‐3 and ‐8 Activation in Vero Cells
Authors: Kajita M. , Katayama H. , Murata T. , Kai C. , Hori M. , Ozaki H.
Published: July 2006

We investigated the signal‐transduction pathway of canine distemper virus‐Onderstepoort (CDV‐Ond) vaccine strain‐mediated apoptosis in Vero cells. Canine distemper virus‐Onderstepoort at a multiplicity of infection (MOI) of 0.1 induced DNA fragmentation 48 h after infection. Immunofluorescence staining revealed that 57% ± 4% of the CDV‐N‐protein‐positive cells were terminal deoxynucleotidyl transferase‐mediated dUTP nick‐end labeling (TUNEL)‐positive, and all TUNEL‐positive cells were CDV‐N‐protein‐positive, indicating that CDV‐Ond induced apoptosis only in the infected cells. We also found that CDV‐Ond infection induced activation of caspase‐3 and caspase‐8. In the semi‐quantitative reverse transcription‐polymerase chain reaction assay for apoptosis‐related genes, the expression of mRNA of the death receptor, Fas, was also increased in CDV‐Ond‐infected cells. In contrast, the expressions of Bcl‐2 and Bax, regulators for intrinsic apoptotic signaling through the mitochondria, did not change. These results suggest that CDV‐Ond induced apoptosis by activating caspase‐3, possibly through caspase‐8 signaling rather than through p53/Bax‐mediated, mitochondrial signaling in the infected cells.
Incidences of Canine Leishmaniasis in an Endemic Area of Southern Italy
Authors: Paradies P. , Capelli G. , Cafarchia C. , De Caprariis D. , Sasanelli M. , Otranto D.
Published: July 2006

Canine leishmaniasis (CanL), caused by Leishmania infantum, is widely distributed in many Mediterranean countries and is considered endemic in southern and central Italy with prevalence reaching up to 48.4%. Determination of the incidence would be useful as a measure of the risk of infection, then to evaluate the usefulness of control measures and to estimate whether a new focus is autochthonous or imported. This study was performed on two sites in the Apulia region of southern Italy, namely sites A and B. A total of 262 dogs were included in the evaluation of incidence, 94 farm dogs from site A and 168 dogs (92 farm and 76 kennel dogs) from site B. The incidence of infection was determined by using two different approaches: in site A by means of incidence density rate (IDR); in site B by the yearly seroconversion rate. In site A, the IDR was calculated at 4.25% dog‐years; in site B the yearly incidence rate was of 9.52% (6.5% and 13.1% in farm and kennel dogs, respectively). The strength and weakness of the two different approaches (i.e. annual monitoring or monthly interval monitoring) for calculating the incidence of CanL in an endemic area have been discussed.
Direct association of a promoter polymorphism in the CD36/FAT fatty acid transporter gene with Type 2 diabetes mellitus and insulin resistance
Authors: Corpeleijn E. , Van Der Kallen C. J. H. , Kruijshoop M. , Magagnin M. G. P. , De Bruin T. W. A. , Feskens E. J. M. , Saris W. H. M. , Blaak E. E.
Published: July 2006

Aims  The membrane‐bound fatty acid transporter CD36/FAT may play a role in disturbed fatty acid handling as observed in the metabolic syndrome and Type 2 diabetes mellitus (T2DM). Genetic variation in the CD36 gene may contribute to the aetiology of diabetes.

Methods  A population‐based cohort in the Netherlands [age > 40 years and body mass index (BMI) > 25 kg/m2] of 675 subjects was phenotyped with respect to glucose metabolism with an oral glucose tolerance test and was genotyped for a known 478C→T substitution and a C/T snp in the upstream promoter region (rs1527479) in the CD36 gene.

Results  T2DM was more prevalent in the TT genotype than in the CC genotype. This was most pronounced in women and in subjects with a high BMI (BMI > 27 kg/m2). In addition, within the group of diabetic patients, the TT genotype was commoner in subjects with increased homeostasis model assessment (HOMA) index for insulin resistance. The 478C→T substitution, previously found in the Japanese population, was not found in our caucasian population.

Conclusions  This is the first study to show a direct association of a CD36 snp with T2DM. Moreover, within the diabetic subjects, this CD36 snp was associated with insulin resistance (HOMA index).
Do people with diabetes who need to talk want to talk?
Authors: Davies M. , Dempster M. , Malone A.
Published: July 2006

Aim  Our objective was to determine whether people with diabetes who ask for psychological support are those who are experiencing clinically significant levels of psychological distress.

Method  Three hundred people with diabetes were asked to complete psychometrically validated questionnaires that assessed subjective need and objective psychological distress.

Results  High levels of psychological distress were reported: 25% reported depressive symptomatology, 41% reported clinically significant levels of anxiety and 51% reported some binge eating behaviour. Participants also indicated a desire to talk to diabetes professionals about various problem areas in diabetes. Those reporting psychological distress, especially depression, were most likely to indicate a desire to talk to someone about living with diabetes.

Conclusions  Those who want to talk are those who need to talk. Future service development issues should acknowledge the needs and expressed wishes of service users.
Age and Second Language Acquisition and Processing: A Selective Overview
Authors: Birdsong David
Published: July 2006

This article provides a selective overview of theoretical issues and empirical findings relating to the question of age and second language acquisition (L2A). Both behavioral and brain‐based data are discussed in the contexts of neurocognitive aging and cognitive neurofunction in the mature individual. Moving beyond the classical notion of “deficient” L2 processing and acquisition, we consider the complementary question of learner potential in postadolescent L2A.
Growth of functional cranial components in rats submitted to intergenerational undernutrition
Authors: Cesani María F. , Orden Alicia B. , Oyhenart Evelia E. , Zucchi Mariel , Muñe María C. , Pucciarelli Héctor M.
Published: July 2006

The aim of the present study was to discover how intergenerational undernutrition affects the growth of major and minor functional cranial components in two generations of rats. Control animals constituted the parental generation (P). The undernourished generations (F1 and F2) were fed 75% of the control diet. Animals were X‐rayed every 10 days from 20 to 100 days of age. The length, width and height of the major (neurocranium and splanchnocranium) and minor (anterior‐neural, middle‐neural, posterior‐neural, otic, respiratory, masticatory and alveolar) cranial components were measured on each radiograph. Volumetric indices were calculated to estimate size variations of these components. Data were processed using the Kruskal–Wallis and Kolmogorov–Smirnov tests for two samples. Impairment in splanchnocranial and neurocranial growth was found, the latter being more affected than the former in F1. Comparison between F2 and F1 animals showed cumulative effects of undernutrition in both major and minor components (anterior‐neural, respiratory, masticatory and alveolar in males, and middle‐neural and respiratory in females). Such differential effects on minor components may reflect a residual mechanical strain resulting from the linkage between components. This phenomenon was clearly observed in the neurocranium and could be understood as an adaptive response to the demands of the associated functional matrices.
In vitro degradation of articular cartilage: does trypsin treatment produce consistent results?
Authors: Moody H. R. , Brown C. P. , Bowden J. C. , Crawford R. W. , McElwain D. L. S. , Oloyede A. O.
Published: July 2006

It is common practice in laboratories to create models of degraded articular cartilage in vitro and use these to study the effects of degeneration on cartilage responses to external stimuli such as mechanical loading. However, there are inconsistencies in the reported action of trypsin, and there is no guide on the concentration of trypsin or the time to which a given sample can be treated so that a specific level of proteoglycan depletion is achieved. This paper argues that before any level of confidence can be established in comparative analysis it is necessary to first obtain samples with similar properties. Consequently, we examine the consistency of the outcome of the artificial modification of cartilage relative to the effects of the common enzyme, trypsin, used in the process of in vitro proteoglycan depletion. The results demonstrate that for a given time and enzyme concentration, the action of trypsin on proteoglycans is highly variable and is dependent on the initial distribution and concentration of proteoglycans at different depths, the intrinsic sample depth, the location in the joint space and the medium type, thereby sounding a note of caution to researchers attempting to model a proteoglycan‐based degeneration of articular cartilage in their experimental studies.
Four Components Describe Behavioral Symptoms in 1,120 Individuals with Late‐Onset Alzheimer's Disease
Authors: Hollingworth Paul , Hamshere Marian L. , Moskvina Valentina , Dowzell Kimberley , Moore Pamela J. , Foy Catherine , Archer Nicola , Lynch Aoibhinn , Lovestone Simon , Brayne Carol , Rubinsztein David C. , Lawlor Brian , Gill Mike , Owen Michael J. , Williams Julie
Published: July 2006

OBJECTIVES: To investigate behavioral components of Alzheimer's disease (AD) and to analyze behavioral components in relation to disease severity, apolipoprotein E genotype (APOE), sex, years of education, age at onset, and cognitive impairment.

DESIGN: Cross‐sectional study.

SETTING: Data were collected from community‐dwelling individuals and those residing in nursing homes.

PARTICIPANTS: A total of 1,120 individuals meeting National Institute of Neurological and Communicative Disorders and Stroke/Alzheimer's Disease and Related Disorders Association criteria for late‐onset probable AD.

MEASUREMENTS: Behavioral symptoms were assessed using the Neuropsychiatric Inventory. First‐order polychoric correlations, controlling for disease severity, between the 12 symptom domain scores were estimated, and the resulting matrix underwent principal components analysis.

RESULTS: Four interpretable components were identified: behavioral dyscontrol (euphoria, disinhibition, aberrant motor behavior, and sleep and appetite disturbances), psychosis (delusions and hallucinations), mood (depression, anxiety, and apathy), and agitation (aggression and irritability). Scores on the four components were associated with severity of cognitive impairment. Higher behavioral dysfunction, agitation, and mood component scores were associated with lower age at onset. Behavioral dysfunction and mood component scores were associated with sex. None of the components were associated with age at assessment, years of education, or number of APOE ɛ4 alleles.

CONCLUSION: Four behavioral components were identified that were comparable with those observed previously. Future analysis of these components will strengthen understanding of the underlying pathology of behavioral symptoms and AD.
Satisfaction with Hospital at Home Care
Authors: Leff Bruce , Burton Lynda , Mader Scott , Naughton Bruce , Burl Jeffrey , Clark Rebecca , Greenough William B. , Guido Susan , Steinwachs Donald , Burton John R.
Published: July 2006

OBJECTIVES: To examine differences in satisfaction with acute care between patients who received treatment in a physician‐led substitutive Hospital at Home program and those who received usual acute hospital care.

DESIGN: Survey questionnaire of participants in prospective, nonrandomized clinical trial.

SETTING: Three Medicare‐managed care health systems and a Department of Veterans Affairs Medical Center.

PARTICIPANTS: Two hundred fourteen community‐dwelling elderly patients who required acute hospital admission for community‐acquired pneumonia, exacerbation of chronic heart failure, exacerbation of chronic obstructive pulmonary disease, or cellulitis, 84 of whom were treated in Hospital at Home and 130 in the acute care hospital.

INTERVENTION: Treatment in a Hospital at Home model of care that substitutes for treatment in an acute care hospital.

MEASUREMENTS: A 40‐question survey measuring nine domains of care for patients and a 37‐question survey measuring eight domains of care for family members.

RESULTS: A higher proportion of patients were satisfied with treatment in Hospital at Home than with the acute care hospital in eight of nine domains, and this difference was statistically different in four domains. Hospital at Home patients were more likely than acute hospital patients to be satisfied with their physician (adjusted odds ratio (AOR)=3.84, 95% confidence interval (CI)=1.32–11.19), comfort and convenience of care (AOR=6.52, 95% CI=1.97–21.56), admission processes (AOR=5.90, 95% CI=2.21–5.76), and the overall care experience (AOR=2.98, 95% CI=1.08–8.21). Family members of patients treated in Hospital at Home were also more likely to be satisfied with multiple domains of care.

CONCLUSION: Hospital at Home care was associated with greater satisfaction than acute hospital inpatient care for patients and their family members. These findings support further dissemination of the Hospital at Home care model.
Management of Far‐Field R Wave Sensing for the Avoidance of Inappropriate Mode Switch in Dual Chamber Pacemakers: Results of the FFS‐Test Study
Authors: KOLB CHRISTOF , WILLE BERND , MAURER DOMINIK , SCHUCHERT ANDREAS , WEBER RALF , SCHIBGILLA VOLKER , KLEIN NORBERT , HÜMMER ALEXANDER , SCHMITT CLAUS , ZRENNER BERNHARD ,   on behalf of the FFS‐Test Study Group
Published: July 2006

Background and Objective: Far‐field R wave sensing (FFS) in the atrial channel of dual chamber pacemakers is a relevant source for inappropriate mode switch from the DDD mode to the DDI or VDI mode. Inappropriate loss of atrioventricular synchrony due to false positive mode switch is hemodynamically disadvantageous, may induce atrial tachyarrhythmias, can lead to pacemaker syndrome, and impairs the reliability of pacemaker Holter data. The aim of the study was to determine whether individual adjustment of the postventricular atrial blanking period (PVAB) based on an additional test is effective in avoiding inappropriate mode switch due to FFS when compared with standard programming of the PVAB.

Methods: A total of 207 patients were supplied with a St. Jude Medical Identity DR® or Identity ADx DR® dual chamber pacemaker for sinus nodal disease (n = 84), atrioventricular block (n = 79), binodal disease (n = 35), or other indications (n = 9). At hospital discharge, they were randomized to an individually optimized PVAB (n = 100) or to a control group with the PVAB left at the nominal of 100 msec (n = 107). Primary endpoint was the occurrence of inappropriate mode switch due to FFS within 3 months after pacemaker implantation assessed by stored electrograms of the pacemaker.

Results: At the 3‐month follow‐up, 28/107 (26%) patients with the standard programming of the PVAB showed at least one episode of inappropriate mode switch due to FFS versus 10/100 (10%) patients with optimized PVAB (P < 0.01). The optimized PVAB was shorter than the nominal PVAB in about one‐third of patients and longer in about two‐third of patients. Different atrial lead localizations were not associated with the occurrence of inappropriate mode switch.

Conclusions: Individual adjustment of the PVAB significantly reduces the incidence of inappropriate mode switch due to FFS.
External and Endoluminal Analysis of Left Atrial Anatomy and the Pulmonary Veins in Three‐Dimensional Reconstructions of Magnetic Resonance Angiography: The Full Insight from Inside
Authors: SCHMIDT BORIS , ERNST SABINE , OUYANG FEIFAN , CHUN K.R. JULIAN , BROEMEL THOMAS , BÄNSCH DIETMAR , KUCK KARL‐HEINZ , ANTZ MATTHIAS
Published: July 2006

Introduction: The detailed knowledge of the individual pulmonary vein (PV) anatomy may help to prevent serious complications during PV isolation (PVI). The purpose of this study was to determine the geometry of the PV ostia and their spatial relation to adjacent structures in external (ex 3D) and endoluminal (en 3D) three‐dimensional reconstructions of magnetic resonance angiographies (MRAs).

Methods and Results: Ex 3D and en 3D of the left atrium (LA) and the PVs of 28 patients were calculated. Diameters and the shape of PV ostia were assessed. In addition, the distances between ipsilateral PV ostia, the LA isthmus line, the roof line and the distance between the left PV and the LA appendage (LAA) were measured. Both ex 3D and en 3D are useful tools to determine the dimensions and the geometry of PVs. En 3D facilitates the identification of common PV ostia (15/28 patients). In en 3D, ipsilateral PV ostia are separated by a narrow myocardial ridge of less than 4 mm in 19/38 PVs (mean 4.3 ± 1 mm; 4.6 ± 2 mm with ex 3D). LAA and the LPV ostia are separated by a ridge of less than 4 mm in 12/28 PVs measured with en 3D (4.8 ± 2 mm; 6.4 ± 2 mm with ex 3D).

Conclusions: Both ex 3D and en 3D reconstructions of MRA precisely visualize the complex LA anatomy. Exact determination of PV ostial geometry is facilitated with en 3D and provides important anatomical information for the PVI strategy. According to our data, individual encircling of every PV is strongly discouraged.
Insulin‐like growth factor 1 signaling regulates cytosolic sialidase Neu2 expression during myoblast differentiation and hypertrophy
Authors: Fanzani Alessandro , Colombo Francesca , Giuliani Roberta , Preti Augusto , Marchesini Sergio
Published: July 2006

Cytosolic sialidase (neuraminidase 2; Neu2) is an enzyme whose expression increases during myoblast differentiation. Here we show that insulin‐like growth factor 1 (IGF1)‐induced hypertrophy of myoblasts notably increases Neu2 synthesis by activation of the phosphatidylinositol 3‐kinase/AKT/mammalian target of rapamycin (P13K/AKT/mTOR) pathway, whereas the proliferative effect mediated by activation of the extracellular regulated kinase 1/2 (ERK1/2) pathway negatively contributed to Neu2 activity. Accordingly, the differentiation L6MLC/IGF‐1 cell line, in which the forced postmitotic expression of insulin‐like growth factor 1 stimulates a dramatic hypertrophy, was accompanied by a stronger Neu2 increase. Indeed, the hypertrophy induced by transfection of a constitutively activated form of AKT was able to induce high Neu2 activity in C2C12 cells, whereas the transfection of a kinase‐inactive form of AKT prevented myotube formation, triggering Neu2 downregulation. Neu2 expression was strictly correlated with IGF‐1 signaling also in C2 myoblasts overexpressing the insulin‐like growth factor 1 binding protein 5 and therefore not responding to endogenously produced insulin‐like growth factor 1. Although Neu2‐transfected myoblasts exhibited stronger differentiation, we demonstrated that Neu2 overexpression does not override the block of differentiation mediated by PI3 kinase and mTOR inhibitors. Finally, Neu2 overexpression did not modify the ganglioside pattern of C2C12 cells, suggesting that glycoproteins might be the target of Neu2 activity. Taken together, our data demonstrate that IGF‐1‐induced differentiation and hypertrophy are driven, at least in part, by Neu2 upregulation and further support the significant role of cytosolic sialidase in myoblasts.
Alpha‐fetoprotein antagonizes X‐linked inhibitor of apoptosis protein anticaspase activity and disrupts XIAP–caspase interaction
Authors: Dudich Elena , Semenkova Lidia , Dudich Igor , Denesyuk Alexander , Tatulov Edward , Korpela Timo
Published: July 2006

Previous results have shown that the human oncoembryonic protein α‐fetoprotein (AFP) induces dose‐dependent targeting apoptosis in tumor cells, accompanied by cytochrome c release and caspase 3 activation. AFP positively regulates cytochrome c/dATP‐mediated apoptosome complex formation in a cell‐free system, stimulates release of the active caspases 9 and 3 and displaces cIAP‐2 from the apoptosome and from its complex with recombinant caspases 3 and 9 [Semenkova et al. (2003) Eur. J. Biochem. 270, 276–282]. We suggested that AFP might affect the X‐linked inhibitor of apoptosis protein (XIAP)–caspase interaction by blocking binding and activating the apoptotic machinery via abrogation of inhibitory signaling. We show here that AFP cancels XIAP‐mediated inhibition of endogenous active caspases in cytosolic lysates of tumor cells, as well as XIAP‐induced blockage of active recombinant caspase 3 in a reconstituted cell‐free system. A direct protein–protein interaction assay showed that AFP physically interacts with XIAP molecule, abolishes XIAP–caspase binding and rescues caspase 3 from inhibition. The data suggest that AFP is directly involved in targeting positive regulation of the apoptotic pathway dysfunction in cancer cells inhibiting the apoptosis protein function inhibitor, leading to triggering of apoptosis machinery.
Tertiary teaching excellence: The CETLs scheme in England
Authors: Chalkley Brian
Published: July 2006

Abstract:  This article describes the establishment of Centres for Excellence in Teaching and Learning (CETLs) by the Higher Education Funding Council in England. It outlines this approach to enhancing effective university teaching and learning and discusses four CETLs that are closely related to university geography departments and dedicated to the themes of active learning, spatial literacy, experiential learning and education for sustainable development.
Elasticity of Energy Demand and Challenges for China's Energy Industry
Authors: Yin Jason Zunsheng , Gates David Forrest
Published: July 2006

The rapid growth of energy demand, the lagging growth of energy production and rising pollution problems have raised concerns in several policy areas, including the availability and cost of energy supply and the possibility of further adverse impacts on the environment. This paper begins with an overview of recent developments in energy demand and supply in China. Using a traditional demand elasticity approach, it analyzes the elasticity of each of four major energy end uses and the potential for adjustments in their relationships. The paper concludes with suggestions for public policy to meet the challenge of growing energy demand and implications for the private sector, including both private and foreign investments.

(Edited by Zhinan Zhang)
How we do it: Tympanoplasty: are different three‐ and four‐frequency averages comparable?
Authors: Dawes P.J.D. , Welch D. , Lee P.
Published: July 2006

Keypoints

• The results of tympanoplasty may be reported in a variety of ways. Pure‐tone audiometry underpins reporting, yet there is no constancy in the pure‐tone threshold average used. We examine the relationship between the 0.5, 1, 2 kHz, 0.5, 1, 2, 3 kHz and 0.5, 1, 2, 4 kHz pure‐tone audiometry averages.

• Using audiometric data collected for 77 patients, we have compared hearing threshold using three different frequency averages derived from pure‐tone audiometry.

• The 0.5, 1, 2 kHz, 0.5, 1, 2, 3 kHz and 0.5, 1, 2, 4 kHz three‐ and four‐frequency averages are significantly different, this difference being primarily determined by the changes in the 4‐kHz threshold. Using an average including 4 kHz results in 8% few patients achieving an ABG closure to within either 10 dB or 20 dB.

• When comparing surgical results with others, surgeons should use reports employing comparable audiometric measures of analysis.
How we do it: An audit of Action on ENT baseline standards in otolaryngology departments in England, UK
Authors: Persaud R. , Hajioff D. , Georgalas C. , Bentley M. , Silva S. , Narula A.
Published: July 2006

Keypoints

• An internet‐based audit was conducted to determine how well English otolaryngology departments apply Action on ENT baseline clinical and administrative standards.

• A total of 91% (97 of 107) departments responded.

• Only 8% of 97 departments met all 23 standards but the majority complied with most standards.

• Microsuction and outpatient endoscopy were almost universally available (99% and 97% respectively) and 98% monitored in‐patient and day surgery activity.

• Compliance was poor (<60%) for three standards: common waiting lists for common conditions (51%), facilities to elicit patient feedback (56%) and the inclusion of a treatment plan in the notes (46%). More than one in four departments lacked dedicated facilities to treat children or a lead clinician for paediatric audiology, despite the Children Acts of 1989 and 2004.

• It is hoped that this audit will help sub‐optimal units to correct their deficiencies.
Chaotic Behavior of a Symmetric Laminate With Transient Thermal Field
Authors: He Xiaoling
Published: July 2006

A symmetric isotropic laminate in a simply supported boundary condition is analyzed for its nonlinear dynamic response subjected to a nonuniform transient thermal field. The equation of motion of a modified Duffing type in a decoupled modal form is obtained for both orthotropic and isotropic symmetric laminate from the reduction of the governing equation of motion by using a Galerkin-type method. Thermally induced nonlinear response and thermal mechanically induced response are investigated in a multimode analysis. The influence of the transient thermal field is found to cause drastically different modal response from that due to the steady-state thermal field. Chaos is found being induced by the transient in-plane thermal field, or by both transient in-plane and transverse thermal fields. Unique bifurcation behavior is observed with different thermal frequencies. Different loading levels can cause transition between chaos and quasi-periodic oscillations.