bluuebunny/crossref_metadata_2025 huggingface dataset:
FE modelling of excavation and operation of a shield tunnelling machine
Authors: Komiya Kazuhito
Published: April 2009

A shield tunnelling machine is driven forward by applying mechanical jack forces behind the shield machine tail while excavating the soil in front of the shield machine with its cutting face. In this study, the advance and excavation processes of the shield tunnelling operation are modelled using the finite element method in order to investigate the effect of these construction processes on the ground response. An excavating finite element is introduced, which models the disturbed soil in front of the cutting face. The operation of shield advance and of soil excavation is simulated using the finite element re‐meshing technique at each time step of the analysis. The proposed modelling techniques of shield tunnelling construction are applied to simulate a deep and a triple‐face shield tunnelling project in Tokyo and the numerical results are compared with the field measurements.
Non‐pharmacological management of behavioural symptoms in nursing homes
Authors: Deudon Audrey , Maubourguet Nathalie , Gervais Xavier , Leone Elsa , Brocker Patrice , Carcaillon Laure , Riff Simone , Lavallart Benoît , Robert Philippe Henri
Published: April 2009

Background

Behavioural and psychological symptoms of dementia (BPSD) are often reported in institutions for the elderly.

Objective

To evaluate the effectiveness of a staff education intervention to manage BPSD in older people with a diagnosis of dementia.

Methods

The trial was conducted in 16 nursing homes; 306 patients with a diagnosis of dementia and presenting BPSD were selected. Nursing homes were randomly allocated to an intervention group or a control group. An 8‐week staff education and training programme was conducted in the nursing homes in the intervention group. The main outcome measures were the Cohen‐Mansfield Agitation Inventory (CMAI) and an Observation Scale (OS) score. Assessments were done at baseline (W0), at the end of the ‘intervention’ period (W8) and 12 weeks after (W20).

Results

There was a significant decrease in the global CMAI score between baseline and W8 (−7.8; p > 0.01) and between baseline and W20 (−6.5; p > 0.01) in the intervention group but not in the control group. Results of mixed linear models showed that the CMAI global score, the CMAI physically non‐aggressive behaviours subscale score and verbally non‐aggressive behaviours subscale score significantly decreased in the intervention group (p < 0.001) although there was no significant evolution in the control group. Direct assessment with the OS produced the same pattern of results, with a significant decrease only in the intervention group.

Conclusion

The intervention reduced BPSD in severely demented nursing home residents and this effect was still present 3 months after the end of the programme. Copyright © 2009 John Wiley & Sons, Ltd.
Microstructural status of ipsilesional and contralesional corticospinal tract correlates with motor skill in chronic stroke patients
Authors: Schaechter Judith D. , Fricker Zachary P. , Perdue Katherine L. , Helmer Karl G. , Vangel Mark G. , Greve Douglas N. , Makris Nikos
Published: April 2009

Greater loss in structural integrity of the ipsilesional corticospinal tract (CST) is associated with poorer motor outcome in patients with hemiparetic stroke. Animal models of stroke have demonstrated that structural remodeling of white matter in the ipsilesional and contralesional hemispheres is associated with improved motor recovery. Accordingly, motor recovery in patients with stroke may relate to the relative strength of CST degeneration and remodeling. This study examined the relationship between microstructural status of brain white matter tracts, indexed by the fractional anisotropy (FA) metric derived from diffusion tensor imaging (DTI) data, and motor skill of the stroke‐affected hand in patients with chronic stroke. Voxelwise analysis revealed that motor skill significantly and positively correlated with FA of the ipsilesional and contralesional CST in the patients. Additional voxelwise analyses showed that patients with poorer motor skill had reduced FA of bilateral CST compared to normal control subjects, whereas patients with better motor skill had elevated FA of bilateral CST compared to controls. These findings were confirmed using a DTI‐tractography method applied to the CST in both hemispheres. The results of this study suggest that the level of motor skill recovery achieved in patients with hemiparetic stroke relates to microstructural status of the CST in both the ipsilesional and contralesional hemispheres, which may reflect the net effect of degeneration and remodeling of bilateral CST. Hum Brain Mapp, 2009. © 2009 Wiley‐Liss, Inc.
Does income‐related health inequality change as the population ages? Evidence from Swedish panel data
Authors: Islam M. Kamrul , Gerdtham Ulf‐G. , Clarke Philip , Burström Kristina
Published: April 2009

This paper explains and empirically assesses the channels through which population aging may impact on income‐related health inequality. Long panel data of Swedish individuals is used to estimate the observed trend in income‐related health inequality, measured by the concentration index (CI). A decomposition procedure based on a fixed effects model is used to clarify the channels by which population aging affects health inequality. Based on current income rankings, we find that conventional unstandardized and age–gender‐standardized CIs increase over time. This trend in CIs is, however, found to remain stable when people are instead ranked according to lifetime (mean) income. Decomposition analyses show that two channels are responsible for the upward trend in unstandardized CIs – retired people dropped in relative income ranking and the coefficient of variation of health increases as the population ages. Copyright © 2009 John Wiley & Sons, Ltd.
Labour participation of people living with HIV/AIDS in Spain
Authors: Oliva Juan
Published: April 2009

Objective: This study explores the relationship between the employment status of human immunodeficiency virus (HIV)‐positive individuals and socioeconomic and health characteristics in Spain.

Methods: Data were obtained from four waves of the HIV/AIDS Hospital Survey from the period 2001 to 2004. The sample was composed of 3376 individuals between 16 and 64 years. Assessment of employment participation was performed using a probit model on a wide range of socioeconomic and lifestyle‐related variables.

Results: The main variables explaining the probability of participation in the labour market were age, gender, education level, CD4 cell count, health status, time since HIV diagnosis, psychological impact of contracting the disease or its progression, the most likely means of transmission and intravenous drug use (IDU). The significance of each of these variables differs for men and women as well as for injecting drug users (IDUs) and non‐IDUs.

Conclusions: The employment status of HIV‐positive individuals is directly related to their health status and other personal characteristics. Policies to improve the well‐being of HIV‐positive individuals should not be limited to any one sector as their needs require strategies with a multidisciplinary approach. Copyright © 2009 John Wiley & Sons, Ltd.
Social determinants of health: an economic perspective
Authors: Epstein David , Jiménez‐Rubio Dolores , Smith Peter C. , Suhrcke Marc
Published: April 2009

The World Health Organization has recently received the findings of its Commission on the Social Determinants of Health. The Commission's report offers a remarkable summary of the evidence, and makes a passionate case for government action to address the social determinants of health, especially as they relate to health inequity. This paper summarizes the ways in which economic analysis could strengthen policy under three headings: examining the causal impact of the determinants of health and of associated policies; prioritising actions; and determining the role of government in influencing behaviour. Copyright © 2009 John Wiley & Sons, Ltd.
Phoneutria spider toxins block ischemia‐induced glutamate release, neuronal death, and loss of neurotransmission in hippocampus
Authors: Pinheiro Ana Cristina do Nascimento , da Silva Adriano Jesus , Prado Marco Antonio M. , Cordeiro Marta do Nascimento , Richardson Michael , Batista Monalise Costa , de Castro Junior Célio José , Massensini André Ricardo , Guatimosim Cristina , Romano‐Silva Marco A. , Kushmerick Christopher , Gomez Marcus Vinicius
Published: April 2009

The aim of this study was to investigate the effect of spider toxins on brain injury induced by oxygen deprivation and low glucose (ODLG) insult on slices of rat hippocampus. After ODLG insult cell viabilility in hippocampal slices was assessed by confocal microscopy and epifluorescence using the live/dead kit containing calcein‐AM and ethidium homodimer and CA1 population spike amplitude recording during stimulation of Schaffer collateral fibers. Spider toxins Tx3–3 or Tx3–4 and conus toxins, ω‐conotoxin GVIA or ω‐conotoxin MVIIC are calcium channel blockers and protected against neuronal damage in slices subjected to ODLG insult. Confocal imaging of CA1 region of rat hippocampal slices subject to ischemic insult treated with Tx3–3, Tx3–4, ω‐conotoxin GVIA or ω‐conotoxin MVIIC showed a decrease in cell death that amounted to 68 ± 4.2%, 77 ± 3.8%, 32 ± 2.3%, and 46 ± 2.9%, respectively. This neuroprotective effect of Tx3–4 was corroborated by eletrophysiological recordings of population spikes amplitudes in CA1. The neuroprotection promoted on hippocampal slices by Tx3–3 or Tx3–4 was also observed when the toxins were applied 10, 20, 30, 60, 90, or 120 min after induction of the ODLG injury. During the ischemic insult, glutamate release from slices was increased by 71% (from 7.0 ± 0.3 nM/mg of protein control slices not subjected to ischemia to 12 ± 0.4 nM/mg of protein in slices exposed to ischemia). Tx3–3, Tx3–4, ω‐conotoxin GVIA or ω‐conotoxin MVIIC inhibited the ischemia‐induced increase on glutamate release by 54, 72, 60, and 70%, respectively. Thus Tx3–3 and Tx3–4 provided robust ischemic neuroprotection showing potential as a novel class of agent that exerts neuroprotection in an in vitro model of brain ischemia. © 2009 Wiley‐Liss, Inc.
High chloride concentrations in the soil and groundwater under an oak hedge in the West of France: an indicator of evapotranspiration and water movement
Authors: Grimaldi C. , Thomas Z. , Fossey M. , Fauvel Y. , Merot P.
Published: April 2009

Chloride is a major anion in soil water and its concentration rises essentially as a function of evapotranspiration. Compared to herbaceous vegetation, high transpiration rates are measured for isolated trees, shelterbelts or hedgerows. This article deals with the influence of a tree hedge on the soil and groundwater Cl− concentrations and the possibility of using Cl− as an indicator of transpiration and water movements near the tree rows. Cl− concentrations were measured over 1 year at different depths in the unsaturated zone and in the groundwater along a transect intersecting a bottomland oak hedge. We observed a strong spatial heterogeneity of Cl− concentrations, with very high values up to 2 g l−1 in the unsaturated zone and 1·2 g l−1 in the upper part of the groundwater. This contrasts with the low and homogeneous concentrations (60–70 mg l−1) in the deeper part of the groundwater. Cl− accumulation in the unsaturated zone at the end of the vegetation season allows us to identify the active root zone extension of trees. In winter, upslope of the tree row, downwards leaching partly renews the soil solution in the root zone, while the slow water movement under the trees or farther downslope results in Cl− accumulation and leads to a salinization of the soil and groundwater. This salinization is of the same order as experimental conditions produce negative effects on oak seedlings. The measurement of Cl− concentrations in the unsaturated zone under tree rows at the end of the vegetation season would indicate whether certain topographic, pedological or climatic conditions are likely to favour a strong salinization of the soil, as observed in the present study. Copyright © 2009 John Wiley & Sons, Ltd.
A multimodel assessment of future climatological droughts in the United Kingdom
Authors: Vidal Jean‐Philippe , Wade Steven
Published: April 2009

This paper presents a detailed assessment of future rainfall drought patterns over the United Kingdom. Previously developed bias‐corrected high‐resolution gridded precipitation time series are aggregated to the scale relevant for water resources management, in order to provide 21st‐century time series for 183 hydrologic areas, as computed by six General Circulation Models (GCMs) under two emissions scenarios. The control run data are used as a ‘learning time series’ to compute the Standardized Precipitation Index (SPI) at four different time scales. SPI values for three 30‐year future time slices are computed with respect to these learning time series in order to assess the changes in drought frequency. Multimodel results under the A2 scenario show a dramatic increase in the frequency of short‐term extreme drought class for most of the country. A decrease of long‐term droughts is expected in Scotland, due to the projected increase in winter precipitation. The analysis for two catchment case studies also showed that changes under the B2 scenario are generally consistent with those of the A2 scenario, with a reduced magnitude in changes. The overall increase with time in the spread of individual GCM results demonstrates the utility of multimodel statistics when assessing the uncertainty in future drought indices to be used in long‐term water resources planning. Copyright © 2009 Royal Meteorological Society
Seasonal prediction of lake inflows and rainfall in a hydro‐electricity catchment, Waitaki river, New Zealand
Authors: Purdie J. M. , Bardsley W. E.
Published: April 2009

The Waitaki River is located in the centre of the South Island of New Zealand, and hydro‐electricity generated on the river accounts for 35–40% of New Zealand's electricity. Low inflows in 1992 and 2001 resulted in the threat of power blackouts. Improved seasonal rainfall and inflow forecasts will result in the better management of the water used in hydro‐generation on a seasonal basis.

Researchers have stated that two key directions in the fields of seasonal rainfall and streamflow forecasting are to a) decrease the spatial scale of forecast products, and b) tailor forecast products to end‐user needs, so as to provide more relevant and targeted forecasts.

Several season‐ahead lake inflow and rainfall forecast models were calibrated for the Waitaki river catchment using statistical techniques to quantify relationships between land–ocean–atmosphere state variables and seasonally lagged inflows and rainfall. Techniques included principal components analysis and multiple linear regression, with cross‐validation techniques applied to estimate model error and randomization techniques used to establish the significance of the skill of the models.

Many of the models calibrated predict rainfall and inflows better than random chance and better than the long‐term mean as a predictor. When compared to the range of all probable inflow seasonal totals (based on the 80‐year recorded history in the catchment), 95% confidence limits around most model predictions offer significant skill. These models explain up to 19% of the variance in season‐ahead rainfall and inflows in this catchment.

Seasonal rainfall and inflow forecasting on a single catchment scale and focussed to end‐user needs is possible with some skill in the South Island of New Zealand. Copyright © 2009 Royal Meteorological Society
Latitudinal height couplings between single tropopause and 500 and 100 hPa within the Southern Hemisphere
Authors: Yuchechen Adrián E. , Bischoff Susana A. , Canziani Pablo O.
Published: April 2009

In order to provide further insights into the relationships between the tropopause and different mandatory levels, this paper discusses the coupling between standardized tropopause height anomalies (STHAs) and standardized 500‐hPa and 100‐hPa height anomalies (S5HAs and S1HAs, respectively) within the ‘climatic year’ for three sets of upper‐air stations located approximately along 20°S, 30°S and 45°S. Data used in this research consists in a radiosonde database spanning the period 1973–2007. The mandatory levels are supposed to be included in each radiosonde profile. The tropopause, on the other hand, is calculated from the significant levels available for each sounding using the lapse rate definition. After applying a selection procedure, a basic statistical analysis combined with Fourier analysis is carried out in order to build up the standardized variables. Empirical orthogonal functions (EOFs) in S‐mode are used to get the normal modes of oscillation as well as their time evolution, for STHA/S5HA as well as for STHA/S1HA coupling, separately, within the aforementioned latitudes.

Overall, there are definite cycles in the time evolution associated with each EOF structure at all three latitudes, the semi‐annual wave playing the most important role in most of the cases. Nevertheless, 20°S seems to be the only latitude driven by diabatic heating cycles in the middle atmosphere. Certainly, EOF1 at this latitude has a semi‐annual behaviour and seems to be strongly influenced by the tropical convection seasonality. Apparently, the convectively driven release of latent heat in the middle troposphere affects the time evolution of the EOF1 structure. By contrast, the vertical propagation of planetary waves is raised as a possible explanation for the EOF1 and EOF2 behaviour at latitudes beyond 20°S, in view of the close connection existent between the semi‐annual oscillation (SAO) and the reversion in the direction of the zonal wind. Copyright © 2009 Royal Meteorological Society
Evaluation of the skill and added value of a reanalysis‐driven regional simulation for Alpine temperature
Authors: Prömmel Kerstin , Geyer Beate , Jones Julie M. , Widmann Martin
Published: April 2009

To determine whether the use of regional climate models improves the representation of climate is a crucial topic in climate modelling. An improvement over coarser scale models is expected especially in areas with complex orography or along coastlines. However, some studies have shown no clear added value for regional climate models. In this study a high‐resolution regional climate simulation performed with REMO 5.0 (regional model) over the whole of Europe over the period 1958–1998 is analysed for 2‐m temperature over the European Alps and their surroundings called the Greater Alpine region (GAR). The simulation is driven by perfect boundary conditions at the lateral boundaries provided by the ERA40 reanalysis and spectral nudging of the large‐scale wind fields towards ERA40 values for the upper layers inside the model domain. The added value of the regional simulation (1/6° resolution) is analysed with respect to the driving reanalysis (1.125° resolution).

Both the REMO simulation and the ERA40 reanalysis are validated against different station datasets of monthly and daily mean 2‐m temperature. Correlation analysis shows that the temporal variability of temperature is well represented by both REMO and ERA40, whereas both show considerable biases. The REMO bias reaches 3 K in summer in regions known to experience a problem with summer drying in a number of regional models. The comparison of REMO and ERA40 shows that an added value of the former exists for all regions in winter. For the regions surrounding the Alps, the added value is absent in summer, whereas in the inner Alpine subregions with most complex orography, REMO performs better than ERA40 during the whole year. The only moderate value added by REMO in this hindcast set‐up may be partly explicable by the fact that meteorological measurements are assimilated in the ERA40 reanalysis but not in the REMO simulation. Copyright © 2009 Royal Meteorological Society
Evolution of the oxidative and hydrolytic degradation of biscuits' fatty fraction during storage
Authors: Caponio Francesco , Summo Carmine , Paradiso Vito M. , Pasqualone Antonella , Gomes Tommaso
Published: April 2009

BACKGROUND: There is little information in the scientific literature on the degradation of the fatty fraction of biscuits during storage. Thus two trials were performed utilizing two different kinds of margarine for a better evaluation of the phenomenon.

RESULTS: Covariance analysis of the data evidenced a significant increase of the oxidized triacylglycerols (P < 0.001), together with a significant decrease (P < 0.001) in the amount of monounsaturated and polyunsaturated fatty acids. On the other hand, the level of hydrolytic degradation did not show significant variation.

CONCLUSION: Principal components analysis ascertained that about 60% of the variance of the data could be attributed to the quality of the margarine, while about 30% was ascribable to the increase of oxidative degradation induced by storage. Copyright © 2009 Society of Chemical Industry
HSA binding of HIV protease inhibitors: a high‐performance affinity chromatography study
Authors: Bertucci Carlo , Pistolozzi Marco , Felix Guy , Danielson U. Helena
Published: April 2009

The binding of HIV protease inhibitors, drugs important for anti‐HIV chemotherapy, to HSA was examined by high‐performance affinity chromatography. Frontal analysis was first used to determine the amount of anchored protein and the binding capacity for selected markers on this column. Zonal elution experiments then ranked the HSA bound fraction of the examined compounds. Information on the binding region was obtained by competitive zonal elution experiments using probe compounds with known sites on HSA. An allosteric competition between HIV protease inhibitors (PIs) and valproate (a probe for the bilirubin site) was detected, consistent with a noncooperative binding mechanism. No significant competition was observed between the examined compounds and salicylate or ibuprofen, probes for sites I and II, respectively. The observations were confirmed by circular dichroism spectroscopy, based on the change in the induced circular dichroism signals of selected markers for the main binding sites of HSA when ritonavir was added as the competitor. These results were in good agreement with previous literature reports and provide more details on how PIs are transported in plasma and how they may compete with other drugs in the body.
Longitudinal trajectories of cigarette smoking following rape
Authors: Amstadter Ananda B. , Resnick Heidi S. , Nugent Nicole R. , Acierno Ron , Rheingold Alyssa A. , Minhinnett Robin , Kilpatrick Dean G.
Published: April 2009

Although prior research has identified increases in cigarette smoking following trauma exposure, no studies have examined longitudinal trajectories of smoking following rape. The present investigation identified and characterized longitudinal (<3 months, 3–6 months, and >6 months postassault) trajectories of smoking (N = 152) following a rape in a sample of 268 sexual assault victims participating in a forensic medical exam. Further, the authors examined acute predictors of subsequent smoking trajectories. Of participants endorsing smoking postrape, a two‐class solution was identified, with the majority of participants (74.6%) evidencing moderate smoking with a slight decrease over time and remaining participants showing heavy smoking with a slight increase over time. Having sustained an injury, minority status, and postexamination distress all predicted subsequent smoking trajectory.
The latent structure of the Peritraumatic Dissociative Experiences Questionnaire
Authors: Brooks Robert , Bryant Richard A. , Silove Derrick , Creamer Mark , O'Donnell Meaghan , McFarlane Alexander C. , Marmar Charles R.
Published: April 2009

This paper has been retracted due to a publisher's error: the order of the authors was incorrect. The Editor and Publisher of the Journal of Traumatic Stress apologize to the authors and our readership. The Peritraumatic Dissociative Experiences Questionnaire (PDEQ) is a widely used measure of peritraumatic dissociation, and is presumably a unidimensional construct. Two hundred forty‐seven individuals admitted to five hospitals after traumatic injury were administered the Clinician Administered PTSD Scale, the Hospital Anxiety and Depression Scale, and the PDEQ. Factor analysis indicated that the PDEQ involved two factors containing four items each: one factor (altered awareness) indexes alterations in awareness and the other (derealization) reflects distortions in perceptions of the self and the world. Only the derealization factor was associated with acute stress, anxiety, and depression symptoms. Cross‐validation with independent data provided only partial support for the 2‐factor structure model. These data indicate that peritraumatic dissociation may involve two distinct constructs.
Preparation and Characterization of Novel Quaternized Cellulose Nanoparticles as Protein Carriers
Authors: Song Yongbo , Zhou Jinping , Li Qian , Guo Yi , Zhang Lina
Published: April 2009

Quaternized cellulose (QC) nanoparticles were prepared in distilled water by ionic crosslinking of QC with sodium tripolyphosphate (TPP) for the first time. BSA as a model protein drug was used to investigate the loading and release features of the nanoparticles. The results indicated that QC nanoparticles had high loading efficiency and capacity for BSA. The in vitro BSA release of the QC nanoparticles displayed a burst effect in the first 2 h and then a slow continuous release. Nanoparticles with a higher DS of QC showed a decrease in particle size, an increase in zeta potential, a higher loading efficiency and a slower drug‐release profile. These studies demonstrated that QC nanoparticles are potential protein carriers, and that their physicochemical properties and release profile could be easily adjusted.

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Therapeutic Efficacy of 2‐Methoxyestradiol Microcrystals Encapsulated within Polyelectrolyte Multilayers
Authors: Wang Su He , Shi Xiangyang , Chen Xisui , Baker James R.
Published: April 2009

Development of a novel formulation of anticancer drugs to improve their water‐solubility and bioavailability remains a great challenge. Herein, the potential anticancer agent 2‐methoxyestradiol (2‐ME) was selected as a model drug and was encapsulated within polyelectrolyte (PE) multilayers by layer‐by‐layer deposition of oppositely charged PEs onto the drug microcrystal surfaces. Cell viability and morphology observation of two cell lines reveal that the PE multilayer‐encapsulated 2‐ME microcrystals markedly decrease the cell viability, displaying similar inhibitory effect to that of the conventional formulation of 2‐ME dissolved in ethanol. The current approach to encapsulate hydrophobic drug microparticles may be useful for formulating different drugs for a variety of biological applications.

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Online HPLC‐NMR of PS‐b‐PMMA and Blends of PS and PMMA, 2 ‐ LCCC‐NMR at Critical Conditions of PMMA
Authors: Hiller Wolf , Sinha Pritish , Pasch Harald
Published: April 2009

PS‐b‐PMMA copolymers and blends of PS and PMMA were analyzed by the online coupling of LC at the critical point of adsorption and 1H NMR. The separation of the polymers was carried out at chromatographic conditions which correspond to the critical point of PMMA and the size exclusion mode of PS. It was shown that blends of PS and PMMA homopolymers could be well separated at critical conditions of PMMA. The analysis of both the copolymers and the blends were carried out by online coupled 1H NMR. The block copolymers were analyzed with respect to the chemical composition. LCCC‐NMR coupling was allowed to determine the individual blocks of the copolymers regarding molar mass. The data were compared with the separation at critical conditions of PS.

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Novel Biodegradable Heterografted Polymer Brushes Prepared via a Chemoenzymatic Approach
Authors: Hans Marc , Xiao Yan , Keul Helmut , Heise Andreas , Moeller Martin
Published: April 2009

Biodegradable heterografted molecular bottle brushes were prepared in two steps starting with a linear polyglycidol as a macroinitiator. First, ca. 45% of the polyglycidol hydroxy groups were grafted with ε‐caprolactone via enzymatic catalysis. Selective end capping of the hydroxy groups at the graft ends was achieved via enzymatic esterification with vinyl acetate or vinyl acrylate. Finally, poly(L‐lactide) grafts were attached to the remaining polyglycidol hydroxy groups by chemically catalyzed ring‐opening polymerization. The successful synthesis of the heterografted comb‐shaped brushes was confirmed by NMR and SEC analyses. Additionally, the feasibility of microsphere formulation was described.

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Microwave‐Assisted Modification of Poly(vinylimidazolium salts) via N,N‐Dimethylformamide Decomposition
Authors: Dickmeis Marcus , Ritter Helmut
Published: April 2009

The modification of poly(1‐propyl‐3‐vinylimidazolium bromide) (3a), poly(1‐hexyl‐3‐vinylimidazolium bromide) (3b), poly(1‐isopropyl‐3‐vinylimidazolium bromide) (3c), poly(1‐benzyl‐3‐vinylimidazolium bromide) (3d), poly(1‐(1‐phenylethyl)‐3‐vinylimidazolium bromide) (3e) has been conducted under microwave irradiation using N,N‐dimethylformamide as solvent and reagent. The products were formed by the decomposition of N,N‐dimethylformamide into dimethylamine and carbon monoxide. The proposed structure of the obtained copolymer contains mainly units of 1‐vinylimidazole and some units of amines, formamides, and alkenes. The reaction mechanism was established by use of model compounds 1‐propyl‐3‐methylimidazolium bromide (5a), 1‐hexyl‐3‐methylimidazolium bromide (5b), 1‐isopropyl‐3‐methylimidazolium bromide (5c), 1‐benzyl‐3‐methylimidazolium bromide (5d), 1‐(1‐phenylethyl)‐3‐methylimidazolium bromide (5e), 1‐hexadecyl‐3‐methylimidazolium bromide (5f).

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Synthesis and Characterization of Organic/Inorganic Polyrotaxanes from Polyhedral Oligomeric Silsesquioxane and Poly(ethylene oxide)/α‐Cyclodextrin Polypseudorotaxanes via Click Chemistry
Authors: Zeng Ke , Zheng Sixun
Published: April 2009

Organic/inorganic polyrotaxanes were synthesized via Huisgen 1,3‐dipolar cycloaddition between 3‐azidapropylhepta(3,3,3‐trifluoropropyl) POSS and dialkyne‐terminated PEO/α‐cyclodextrin polypseudorotaxanes. The organic/inorganic hybrid polyrotaxanes were characterized by means of 1H NMR spectroscopy and WAXRD. It was found that the nanosized POSS blocking agents significantly affected the crystal structures of polyrotaxanes. Thermal gravimetric analysis showed that the organic/inorganic hybrid polyrotaxanes exhibited enhanced thermal stability compared to their parent polypseudorotaxanes, in terms of rate of thermal degradation and the summation of char and ceramic yields.

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New Cyclic Olefin Copolymer for the Preparation of Thermally Responsive Luminescent Films
Authors: Donati Filippo , Pucci Andrea , Boggioni Laura , Tritto Incoronata , Ruggeri Giacomo
Published: April 2009

Polymer films with optical properties as indicators to thermal stress were obtained through the controlled dispersion of moderate amounts (≤0.1 wt.‐%) of the 4,4′‐bis(2‐benzoxazolyl)stilbene (BBS) dye into a new semicrystalline ethylene‐norbornene (E‐co‐N, N content of 15.3 mol.‐%) copolymer characterized by a glass transition temperature (Tg) of about 64 °C. All the pristine films showed optical characteristics coming from noninteracting BBS chromophores. In contrast permanent optical changes were detected after film annealing at a T ≥ Tg due to the variation of the BBS supramolecular structure. The easy modulation of the optical features of polymer films by thermal perturbations suggests applications as threshold temperature visual indicators in thermoplastic materials.

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Synthesis of Chitosan Surfactants
Authors: Fricke Nicole , Keul Helmut , Möller Martin
Published: April 2009

Chitosan surfactants were prepared in a three‐step reaction starting with glycol chitosan (GC) and chitosan oligosaccharides (COS). In the case of GC, water‐insoluble products were obtained, the functionalisation of which were proven via IR spectroscopy. Starting with COS, a broad variety of products with different ratios of ionic and hydrophobic side chains were prepared and characterised by NMR and partially by IR spectroscopy. Thermogravimetric analysis showed that the thermal stability of functionalised COS did not change. The critical micelle concentration (cmc) was determined from surface tension measurements to be 0.01 mg · mL−1 for a sample of ionic to hydrophobic units of 1:1.

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Alkylthio‐Substituted Polythiophene: Absorption and Photovoltaic Properties
Authors: Huo Lijun , Zhou Yi , Li Yongfang
Published: April 2009

Two polythiophene derivatives with electron‐donating alkylthio side chains, poly[(3‐hexylthio)thiophene] (P3HST) and poly[(3‐hexylthio)thiophene‐alt‐thiophene] (P3HST‐co‐Th) have been synthesized and characterized. Both P3HST and P3HST‐co‐Th show broader absorption peaks than poly(3‐hexylthiophene). Meanwhile, the alkylthio side chains decrease the HOMO energy level of the polymers, which benefits the higher open circuit voltage of the polymer solar cells (PSCs) based on the polymer as donor. PSCs have been fabricated with the polymers as donor and [6,6]‐phenyl C61 butyric acid methyl ester as acceptor (1: 1, w/w). The devices based on P3HST and P3HST‐co‐Th show an open circuit voltage of 0.63 V, and a power conversion efficiency of 0.34% and 0.5%, respectively, under the illumination of AM1.5, 80 mW · cm−2.

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Water Soluble Star‐block Copolypeptides: Towards Biodegradable Nanocarriers for Versatile and Simultaneous Encapsulation
Authors: Zhuang Wensheng , Liao Lihui , Chen Heru , Wang Jinzhi , Pan Ying , Zhang Lumian , Liu Daojun
Published: April 2009

The synthesis of water soluble star‐block copolypeptides and their encapsulation properties are described. The star‐block copolypeptides, obtained by ring‐opening polymerization of amino acid N‐carboxyanhydrides, consist of a PEI core, a hydrophobic polyphenylalanine or polyleucine inner shell, and a negatively charged polyglutamate outer shell. The encapsulation study showed that these water soluble, amphiphilic star‐block copolypeptides could simultaneously encapsulate versatile compounds ranging from hydrophobic to anionic and cationic hydrophilic guest molecules.

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Similarities in the Structural Organization of Major and Minor Ampullate Spider Silk
Authors: Papadopoulos Periklis , Ene Roxana , Weidner Immanuel , Kremer Friedrich
Published: April 2009

Minor and major ampullate spider silks are studied under varying mechanical stress by static and time‐resolved FT‐IR spectroscopy. This enables one to trace the external mechanical excitation on a microscopic level and to determine for the different moieties the time dependence of the molecular order parameters and corresponding band shifts. It is concluded that the hierarchical nanostructure of both types of silk is similar, being composed of highly oriented nanocrystals, which are interconnected by amorphous chains that obey the worm‐like chain model and have a Gaussian distribution of pre‐strain. By that it is possible to describe the mechanical properties of both silks by two adjustable parameters only, the center and width of the distribution. For major ampullate silk, the observed variability is small in pronounced contrast to the findings for minor ampullate.

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Mesoscopic Membrane Physics: Concepts, Simulations, and Selected Applications
Authors: Deserno Markus
Published: April 2009

The window of a few tens to a few hundred nanometers in length scale is a booming field in lipid membrane research, owing largely to two reasons. First, many exciting biophysical and cell biological processes take place within it. Second, experimental techniques manage to zoom in on this sub‐optical scale, while computer simulations zoom out to system sizes previously unattainable, and both will be meeting soon. This paper reviews a selection of questions and concepts in this field and demonstrates that they can often be favorably addressed with highly simplified simulation models. Among the topics discussed are membrane adhesion to substrates, mixed lipid bilayers, lipid curvature coupling, pore formation by antimicrobial peptides, composition‐driven protein aggregation, and curvature driven vesiculation.

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Rehabilitation treatment of gait in patients with Parkinson's disease with freezing: A comparison between two physical therapy protocols using visual and auditory cues with or without treadmill training
Authors: Frazzitta Giuseppe , Maestri Roberto , Uccellini Davide , Bertotti Gabriella , Abelli Paola
Published: April 2009

Freezing is a disabling symptom in patients with Parkinson's disease. We investigated the effectiveness of a new rehabilitation strategy based on treadmill training associated with auditory and visual cues. Forty Parkinsonian patients with freezing were randomly assigned to two groups: Group 1 underwent a rehabilitation program based on treadmill training associated with auditory and visual cues, while Group 2 followed a rehabilitation protocol using cues and not associated with treadmill. Functional evaluation was based on the Unified Parkinson's Disease Rating Scale Motor Section (UPDRS III), Freezing of Gait Questionnaire (FOGQ), 6‐minute walking test (6MWT), gait speed, and stride cycle. Patients in both the groups had significant improvements in all variables considered by the end of the rehabilitation program (all P = 0.0001). Patients treated with the protocol including treadmill, had more improvement than patients in Group 2 in most functional indicators (P = 0.007, P = 0.0004, P = 0.0126, and P = 0.0263 for FOGQ, 6MWT, gait speed, stride cycle, respectively). The most striking result was obtained for 6MWT, with a mean increase of 130 m in Group 1 compared with 57 m in Group 2. Our results suggest that treadmill training associated with auditory and visual cues might give better results than more conventional treatments. Treadmill training probably acts as a supplementary external cue. © 2009 Movement Disorder Society
De Sitter vacua in simple extended supergravity
Authors: Kehagias A.
Published: April 2009

We show that de Sitter vacua exist in simple extended supergravity theories. In the particular 𝒩 = 2 case we are considering here, we find a de Sitter solution of the supergravity theory with gravity and gravitini turned on by taking into account ψ4 torsion terms.
Higher order conformal perturbation theory
Authors: Schmidt‐Colinet C.
Published: April 2009

We consider a string stretched between two diagonal branes on a bosonic torus under a perturbation of one of the radii. In the world‐sheet description, this corresponds to a perturbation of a conformal field theory with two boundary components. A term in the second order boundary RG equations is related to the change of conformal dimension of the boundary changing operator.
On the tripartite entanglement of three qubits and the entropy of STU black holes
Authors: Rubens W.
Published: April 2009

We show how the entropy of STU black holes is given by the same formula as the tripartite entanglement of three qubits. We explore this link and provide a possible explanation in terms of the wrapping of D3 branes that construct the black holes. This construction also allows us to identify the five parameter generating solution of black holes with a similar one for the qubits.
Nonlinear carrier recombination and transport features in highly excited InN layer
Authors: Nargelas Saulius , Malinauskas Tadas , Kadys Arūnas , Dimakis Emmanouil , Moustakas Theodore D. , Jarašiuūnas Kęstutis
Published: April 2009

A time‐resolved picosecond four‐wave mixing, or transient grating technique has provided novel features of non‐equilibrium carrier recombination and diffusion in wide excitation and temperature range of InN (n0 = 1.4×1018 cm–3) at interband photoexcitation (hν = 1.17 eV). Monitoring of the spatial and temporal carrier dynamics via light diffraction provided a direct way to control the dynamics of photoexcited carrier density N (i.e. integrated over the sample depth) in 5×1017 – 5×1019 cm–3 range. The determined bipolar carrier diffusion coefficient 2 cm2/s and its temperature dependence were used for numerical fitting of carrier in‐depth temporal profiles in non‐homogeneously photoexcited InN layers. The recombination rate was found strongly nonlinear: it followed the 1/τR ∝ B*(n0+N) law and was nearly independent on temperature in T = 15 – 300 K range. These features allowed us to suggest a trap‐assisted Auger recombination being the dominant recombination mechanism in InN. The modelling provided a value of trap–assisted Auger recombination coefficient B* = CTAANT = 8×10–10 cm3 s–1. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Silicon electroluminescent device production via plasma ion implantation
Authors: Bradley Michael P. , Desautels Phillip R. , Hunter Darren , Risch Marcel
Published: April 2009

We discuss the technique of plasma ion implantation (PII) and the type of luminescent centers which can be produced by it. We have focused on high‐dose ion implantation into silicon for bandstructure modification. We have produced electroluminescent silicon using a range of plasma ion species including H+, C+, N+ and a range of ion implant conditions. Analyses of the spectra of electroluminescent centers produced by this technique have been performed. Further work will be required to determine the exact physical mechanisms responsible for these effects. Future prospects for electroluminescent devices based on these effects will be discussed. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Prospects for band gap engineering by plasma ion implantation
Authors: Risch Marcel , Bradley Michael P.
Published: April 2009

The suitability of plasma ion implantation (PII) for band gap engineering will be examined by calculations of the band gap's spatial variation. Plasma Ion Implantation is a method to modify the surface and subsurface properties of materials; the ions surrounding the target are forced into all plasma exposed surfaces simultaneously by virtue of high‐voltage pulses. We calculated the fluence and the ion energy distribution from the dynamic sheath model. The distribution of the ions within the target is subsequently simulated by the TRIDYN software. The concentration profiles are converted into a spatial variation of the band gap. The challenges inherent to the method are discussed by means of the examples of carbon (C) PII in silicon (Si) as well as nitrogen (N) PII in gallium arsenide (GaAs). The ion distribution within the material of the former example is suitable for the formation of the Si‐C alloy. On the other hand, the distribution of N ions in GaAs prevents the formation of the Ga‐As‐N alloy. The discussed methods could be a powerful tool for the prediction of materials properties from the plasma processing parameters, thus helping to design materials. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Near‐infrared inorganic/organic hybrid optical upconverter with an embedded mirror
Authors: Chen Jun , Ban Dayan , Feng Xiaodong , Lu Zhenghong , Fathololoumi Saeed , Thorpe Anthony J. Spring , Liu H. C.
Published: April 2009

We report a hybrid organic‐inorganic optical upconverter with an embedded metal mirror. The device was fabricated through direct tandem integration of an organic light emitting diode (OLED) with an inorganic InGaAs/InP photodetector, converting 1.5 μm infrared light to visible light. It was found that the device with an embedded mirror exhibited a low turn‐on voltage (∼3.2 V) and an enhanced efficiency. The ratio of photocurrent‐induced with an input power density of 0.67 mW/mm2 versus dark‐current‐induced visible light was over 500 at a device bias of 6 V at room temperature. The results show that the embedded mirror at the inorganic‐organic interface plays a vital role in the performance enhancement of a hybrid upconverter. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Modeling of dielectric response of GexSbyTez (GST) materials
Authors: Franta Daniel , Necas David , Frumar Miloslav
Published: April 2009

The models of dielectric response of disordered solids based on parametrization of density of states (PDOS) and parametrization of joint density of states (PJDOS) are discussed in detail for interband and intraband transitions. These models are compared with classical models, i. e. Lorentz, Tauc‐Lorentz and Drude. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Novel long fiber Bragg grating fabrication technique based on push‐pull phase‐shifting interferometry
Authors: Gagné Mathieu , Bojor Lucian , Maciejko Romain , Kashyap Raman
Published: April 2009

We demonstrate a novel UV‐writing technique for fabricating long fiber Bragg gratings (FBGs). The use of electro‐optical phase modulators allows the creation of a continuously moving fringe pattern which can be synchronized with a moving fiber. It is shown that infinitely long FBGs may be fabricated using this technique. Preliminary results are presented. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Third‐order optical nonlinearity of β‐carotene homologues
Authors: Fujiwara Masazumi , Yamauchi Kensei , Sugisaki Mitsuru , Yanagi Kazuhiro , Gall Andrew , Robert Bruno , Cogdell Richard J. , Hashimoto Hideki
Published: April 2009

We investigate the third‐order nonlinear optical property of a range of β‐carotene homologues, which have different numbers (n) of conjugated C=C double bonds from n = 7 to 15, by using third‐harmonic generation Maker fringe technique. The results clearly show that there is a remarkable enhancement of the third‐order optical nonlinearity when n = 15, which is a four fold increase compared with n = 11 (i.e. β‐carotene). (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Optical properties of conductive ZnO films near infrared frequency
Authors: Itoh T. , Matsuyama K. , Shimakawa K. , Orava J. , Wagner T. , Frumar M.
Published: April 2009

To know the optical constants, n and k, in transparent conductive zinc oxide (ZnO) films, both spectroscopic ellipsometry (SE) and reflectance‐transmittance (RT) method have been adopted. The optical constants, n and k deduced from the SE are different from those estimated from the RT method. We will discuss these differences through the deduced physical parameters in magnetron sputtered Ga‐doped ZnO films. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Random laser action in 3‐D ZnO nanostructures
Authors: Miao L. , Tanemura S. , Yang H. Y. , Lau S. P. , Xu G.
Published: April 2009

Room‐temperature ultraviolet random lasing with low threshold pumping power was successfully achieved by ZnO 3‐D random‐wall nanostructure fabricated on ZnO/SiO2/Si substrate through a thermal chemical reaction and vapor transportation deposition method in a simple horizontal tube furnace from the mixed ZnO and graphite powders. The nanorods grown along c‐axis on the substrate are coalesced to form the 3‐D nano‐wall with 80∼100 nm in wall thickness and irregular height ranging of 95‐250 nm. Mueller matrix spectroscopic ellipsometry reveals that evaluated refractive indices n (E) of ZnO nanowalls are well interpreted by taking account of the ratio between ZnO and void achieved by effective medium theory analysis and isotropic depolarization feature of the designated nanowalls. Random lasing action observed in the wide wavelength range between 375 and 395 nm is realized by coherent amplification of the closed‐loop scattered light inside 3‐D random‐wall nanostructure. It is demonstrated that both transverse electric (TE) and transverse magnetic (TM) modes show the same threshold and pumping power dependent trend, while the intensity of TM lasing is weaker than that of TE due to the different scattering strength originated from the features of the inside of nano wall. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)