bluuebunny/crossref_metadata_2025 huggingface dataset:
Infrared and Raman Studies of Structural Relaxation in Amorphous Tetracosane, n-C24H50
Authors: Ishii Kikujiro , Nukaga Masako , Hibino Yukinobu , Hagiwara Shohgo , Nakayama Hideyuki
Published: July 2006

Structural relaxation in amorphous tetracosane n-C24H50 was studied by infrared and Raman spectroscopies. Samples were prepared by vacuum deposition onto cold substrates and the spectral changes were monitored as the temperature was raised stepwise. Several distinguishable relaxation processes were found to take place similarly to the case of amorphous states of other hydrocarbons. However, in contrast to the previous study, we arrived at a conclusion that the initial relaxation of the disordered molecules does not take place in a single step. In the later part of the relaxation, metastable orthorhombic-type subcells were found to appear. They disappear finally when the adjustment of the mutual position of extended molecules occurs to attain the lateral molecular packing of the stable triclinic crystal. The intermolecular interactions along the chain direction are also discussed.
On Measuring the Perceived Onsets of Spontaneous Actions
Authors: Lau Hakwan C. , Rogers Robert D. , Passingham Richard E.
Published: July 2006

We investigated the neural mechanisms underlying the timing procedure that was devised by Libet et al. (1983) to measure the onset of conscious motor intentions in spontaneous actions. We previously showed that, when participants were required to estimate the onset of their intentions using this procedure, the activity in the presupplementary motor area (pre-SMA) was enhanced. Here, we show that when participants were required to estimate the onset of their motor executions (instead of their intentions), the activity in the cingulate motor area was enhanced. Across participants, the degree of this neural enhancement was correlated with the degree of perceptual bias: the higher the degree of enhancement, the earlier the perception. Analysis of data from a previous experiment suggests that the same principle holds true for the relationship between the perceived onset of intentions and the activity in the pre-SMA. We therefore argue that the timing method of Libet et al. (1983) is problematic, because the measuring process affects the neural representations of action and thus also the perceived onsets that the method is designed to measure.
Current Advances in Local Protein Synthesis and Synaptic Plasticity
Authors: Pfeiffer Brad E. , Huber Kimberly M.
Published: July 2006

Local or dendritic protein synthesis is required for long-term functional synaptic change, such as long-term potentiation (LTP) and long-term depression (LTD). LTP and LTD both rely on similar signal transduction cascades, which regulate translation initiation. Current research indicates that the specificity by which new proteins participate in either LTP or LTD may be determined in part by specific RNA-binding proteins as well as activity-dependent capture.
RNA Trafficking and Local Protein Synthesis in Dendrites: An Overview
Authors: Martin Kelsey C. , Zukin R. Suzanne
Published: July 2006

It is now widely accepted that mRNAs localize to dendrites and that translation of these mRNAs is regulated in response to neuronal activity. Recent studies have begun to reveal the underpinnings of these processes and to underscore the importance of local protein synthesis to synaptic remodeling and plasticity.

When Steward and Levy (1982) first reported their observation of polyribosomes at the base of spines, the prevailing view was that all proteins were synthesized in the cell body and then transported to distal compartments of neurons. Steward and Levy's discovery, however, raised the intriguing possibility that mRNAs could be transported to synapses and locally translated in response to synaptic stimulation. This provided an elegant mechanism for spatially restricting gene expression within the neuron, such that individual synapses could independently regulate their morphology and efficacy, in a persistent, protein synthesis-dependent manner, in response to specific stimuli. It is now widely accepted that mRNAs do localize to dendrites and that translation of these mRNAs contributes to synaptic plasticity. As is evident from the collection of Mini-Reviews on dendritic protein synthesis in this issue ofThe Journal of Neuroscience, the field has evolved to focus on a series of key questions, including the following: (1) what mRNAs are present in dendrites? (2) How are these mRNAs transported from the nucleus into the dendrite? (3) How is translation of these mRNAs regulated by neuronal activity? and (4) What is the function of local translation of specific transcripts? In this brief introductory overview, we will consider each of these questions in turn.
Highways and Population Change*
Authors: Voss Paul R. , Chi Guangqing
Published: July 2006

Abstract  In this paper we return to an issue often discussed in the literature regarding the relationship between highway expansion and population change. Typically it simply is assumed that this relationship is well established and understood. We argue, following a thorough review of the relevant literature, that the notion that highway expansion leads to increased population growth in the vicinity of the improved infrastructure finds only weak and often conflicting support. Using data on all major highway expansions in Wisconsin covering the period from the late‐1960s through the 1990s from the Wisconsin Department of Transportation (WisDOT), and census data at the minor civil division (MCD) level covering the period 1970 to 2000, we deploy the analytical tools of geographic information system (GIS) software, and theory from the expanding literature in spatial analysis and modeling, to take a fresh look at this relationship. Our analysis reveals that there is a modest relationship between highway expansion and population growth among MCDs within 10–20 miles of the expanded major highway. The causal structure, however, is complex. Our starting hypothesis argues that population growth precedes highway expansion as frequently as population growth results from highway expansion, but the data show otherwise. The dominant causal influence appears to flow from highway expansion to population growth.
Bullying Victimization Uniquely Contributes to Adjustment Problems in Young Children: A Nationally Representative Cohort Study
Authors: Arseneault Louise , Walsh Elizabeth , Trzesniewski Kali , Newcombe Rhiannon , Caspi Avshalom , Moffitt Terrie E.
Published: July 2006

OBJECTIVE. It has been shown that bullying victimization is associated with behavior and school adjustment problems, but it remains unclear whether the experience of bullying uniquely contributes to those problems after taking into account preexisting adjustment problems.

METHODS. We examined bullying in the Environmental Risk Study, a nationally representative 1994–1995 birth cohort of 2232 children. We identified children who experienced bullying between the ages of 5 and 7 years either as pure victims or bully/victims. We collected reports from mothers and teachers about children’s behavior problems and school adjustment when they were 5 years old and again when they were age 7.

RESULTS. Compared with control children, pure victims showed more internalizing problems and unhappiness at school when they were 5 and 7 years. Girls who were pure victims also showed more externalizing problems than controls. Compared with controls and pure victims, bully/victims showed more internalizing problems, more externalizing problems, and fewer prosocial behaviors when they were 5 and 7 years. They also were less happy at school compared with control children at 7 years of age. Pure victims and bully/victims showed more behavior and school adjustment problems at 7 years of age, even after controlling for preexisting adjustment problems at 5 years of age.

CONCLUSIONS. Being the victim of a bully during the first years of schooling contributes to maladjustment in young children. Prevention and intervention programs aimed at reducing mental health problems during childhood should target bullying as an important risk factor.
Pediatric Autonomic Disorders
Authors: Axelrod Felicia B. , Chelimsky Gisela G. , Weese-Mayer Debra E.
Published: July 2006

The scope of pediatric autonomic disorders is not well recognized. The goal of this review is to increase awareness of the expanding spectrum of pediatric autonomic disorders by providing an overview of the autonomic nervous system, including the roles of its various components and its pervasive influence, as well as its intimate relationship with sensory function. To illustrate further the breadth and complexities of autonomic dysfunction, some pediatric disorders are described, concentrating on those that present at birth or appear in early childhood.
How Athens’ Olympic stadium was finally pulled together
Authors: Siriani Federico , Di Silverio Massimo
Published: July 2006

Completing the dramatic 18 500 t main stadium roof for the 2004 Athens Olympics was tension engineering in every sense. The 304 m long, 80 m high cable-stayed steel and polycarbonate roof designed by Santiago Calatrava was literally pulled together at the last minute, just as it was on the verge of being abandoned. This paper describes how the two sinuous halves of the roof were built 70 m away from each side of the existing 20-year-old stadium, using a series of strand-jack towers, and then how they were drawn together using a strand-free pulling system devised at the eleventh hour. The final pull was completed on 6 June, just four days before the first test events. It is a timely reminder of the huge challenges that engineers invariably have to overcome in delivering monumental sporting arenas on time.
Developing productive relationships in civil engineering
Authors: Platts Jim , Tomasevic Vladimir
Published: July 2006

In any group of people, cohesion depends on relationship competence. This involves insightful, intuitive and empathetic noticing of each others’ needs and proactive taking of responsibility to help each other, deeply founded in good intent; indeed, it is the basis of all professional behaviour. This paper reports on a study of productive relationships in civil engineering that has given rise to a model and a framework for guiding and assessing the development of this aspect of professional competence. The model is outlined in the paper along with comments from civil engineers and other construction professionals.
Correlation between activation of the sympathetic nervous system estimated by plasma concentrations of norepinephrine and Doppler echocardiographic variables in dogs with acquired heart disease
Authors: Santos Mário Marcondes , Strunz Célia M. C. , Larsson Maria H. M. A.
Published: July 2006

Objective—To evaluate correlations between plasma concentrations of norepinephrine and Doppler echocardiographic variables for dogs with degenerative mitral valve disease (DMVD) or dilatative cardiomyopathy (DCM) to better understand the time course and magnitude of sympathetic activation in dogs with heart failure (HF).

Animals—15 healthy dogs, 15 dogs with DMVD, and 15 dogs with DCM.

Procedures—Dogs were positioned in lateral recumbency with minimal restraint for at least 20 minutes. Plasma samples were obtained and assayed by use of high-performance liquid chromatography. Concentrations were correlated with HF classification and with the main Doppler echocardiographic variables for each group.

Results—Mean ± SD norepinephrine concentration was significantly higher in dogs with DMVD (494.4 ± 204.8 pg/mL) or DCM (655.7 ± 652.5 pg/mL) than in healthy dogs (205.8 ± 78.9 pg/mL), but concentrations did not differ significantly between the 2 groups with HF. Correlations were not detected between norepinephrine and heart rate or any M-mode echocardiographic variables evaluated, except for fractional shortening (FS) in DCM dogs. In that group, norepinephrine was inversely correlated with FS values. In DMVD dogs, no significant correlation was found between norepinephrine and the left atrium-to-aortic root ratio or mitral regurgitation.

Conclusions and Clinical Relevance—A proportional inverse correlation exists between norepinephrine and FS values in dogs with DCM. However, norepinephrine concentration was not correlated with the evaluated echocardiographic variables in dogs with DMVD. Sympathetic antagonists should be evaluated as a treatment option because of the increased plasma concentrations of norepinephrine detected in dogs with HF.
Compensation for changes in hoof conformation between shoeing sessions through the adaptation of angular kinematics of the distal segments of the limbs of horses
Authors: van Heel Meike C. V. , van Weeren P. René , Back Willem
Published: July 2006

Objective—To determine the mechanism that enables horses to partially counteract the shift of the center of pressure under the hoof induced by changes in hoof morphology attributable to growth and wear during a shoeing interval.

Animals—18 clinically sound Warmblood horses.

Procedures—Horses were evaluated 2 days and 8 weeks after shoeing during trotting on a track containing pressure-force measuring plates and by use of a synchronous infrared gait analysis system set at a frequency of 240 Hz. All feet were trimmed toward straight alignment of the proximal, middle, and distal phalanges and shod with standard flat shoes.

Results—Temporal characteristics such as stance time and the time between heel lift and toe off (ie, breakover duration) did not change significantly as a result of shoeing interval. Protraction and retraction angles of the limbs did not change. Compensation was achieved through an increase in the dorsal angle of the metacarpohalangeal or metarsophalangeal (fetlock) joint and a concomitant decrease of the dorsal angle of the hoof wall and fetlock. There was an additional compensatory mechanism in the hind limbs during the landing phase.

Conclusions and Clinical Relevance—Horses compensate for changes in hoof morphology that develop during an 8-week shoeing interval such that they are able to maintain their neuromuscular pattern of movement. The compensation consists of slight alterations in the angles between the distal segments of the limb. Insight into natural compensation mechanisms for hoof imbalance will aid in the understanding and treatment of pathologic conditions in horses.
Stable and Efficient White Electroluminescent Devices Based on a Single Emitting Layer of Polymer Blends
Authors: Shih P.‐I , Tseng Y.‐H. , Wu F.‐I. , Dixit A. K. , Shu C.‐F.
Published: July 2006

An efficient orange‐light‐emitting polymer (PFTO‐BSeD5) has been developed through the incorporation of low‐bandgap benzoselenadiazole (BSeD) moieties into the backbone of a blue‐light‐emitting polyfluorene copolymer (PFTO poly{[9,9‐bis(4‐(5‐(4‐tert‐butylphenyl)‐[1,3,4]‐oxadiazol‐2‐yl)phenyl)‐9′,9′‐di‐n‐octyl‐[2,2′]‐bifluoren‐7,7′‐diyl]‐stat‐[9,9‐bis(4‐(N,N‐di(4‐n‐butylphenyl)amino)phenyl)‐9′,9′‐di‐n‐octyl‐[2,2′]‐bifluoren‐7,7′‐diyl]}) that contains hole‐transporting triphenylamine and electron‐transporting oxadiazole pendent groups. A polymer light‐emitting device based on this copolymer exhibits a strong, bright‐orange emission with Commission Internationale de L'Eclairage (CIE) color coordinates (0.45,0.52). The maximum brightness is 13 716 cd m–2 and the maximum luminance efficiency is 5.53 cd A–1. The use of blends of PFTO‐BSeD5 in PFTO leads to efficient and stable white‐light‐emitting diodes—at a doping concentration of 9 wt %, the device reaches its maximum external quantum efficiency of 1.64 % (4.08 cd A–1). The emission color remains almost unchanged under different bias conditions: the CIE coordinates are (0.32,0.33) at 11.0 V (2.54 mA cm–2, 102 cd m–2) and (0.31,0.33) at 21.0 V (281 mA cm–2, 7328 cd m–2). These values are very close to the ideal CIE chromaticity coordinates for a pure white color (0.33,0.33).
Macroporous Titania Monolith Prepared via Sol‐gel Process with Polymer Foam as the Template
Authors: Ren Jian , Du Zhong‐Jie , Zhang Chen , Li Hang‐Quan
Published: July 2006

Macroporous titania monoliths were prepared via sol‐gel method using polymer foam as templates. The polymer foam polymerized via concentrated emulsion polymerization was immerged in a solution of titanium(IV) isopropoxide in 2‐propanol, which underwent a sol‐gel process. The organic components were subsequently removed by calcination. The effects of various parameters, including the nature of the monomer, the volume fraction of dispersed phase of the concentrated emulsion, and concentration of the sol‐gel solution were investigated. The SEM micrographs of the macroporous titania monoliths thus obtained showed that the porous structure of the final material was effectively controllable.
Self‐Assembled Octadecyltrimethoxysilane Monolayers Enabling Selective‐Area Atomic Layer Deposition of Iridium
Authors: Färm E. , Kemell M. , Ritala M. , Leskelä M.
Published: July 2006

A preparation method for octadecyltrimethoxysilane (ODS) self‐assembled monolayers (SAMs) that enables the selective‐area ALD of iridium is studied using an ALD process for iridium at 225 °C. ODS SAMs were prepared from the gas phase by two preparation methods: either with exposure to ODS only, or with alternate exposures to ODS and water. SAMs were patterned with a lift‐off process using aluminium as a mask layer.
The Rap GTPases mediate CXCL13‐ and sphingosine1‐phosphate‐induced chemotaxis, adhesion, and Pyk2 tyrosine phosphorylation in B lymphocytes
Authors: Durand Caylib A. , Westendorf Jens , Tse Kathy W. K. , Gold Michael R.
Published: July 2006

The localization of B cells to lymphoid organs where they can become activated and differentiate into antibody‐secreting plasma cells is controlled by multiple chemoattractants that promote cell migration and integrin‐mediated adhesion. CXCL13 and sphingosine 1‐phosphate (S1P) are two important chemoattractants that control the trafficking of B cells. CXCL13 directs B lymphocytes to lymphoid follicles where they receive survival signals and, if activated, undergo a germinal center response. In contrast, S1P allows B cells and plasma cells to exit lymphoid organs and re‐enter the circulation. The Rap1 GTPase is a key regulator of cell adhesion and cell migration in a number of systems. We now show that Rap activation is required for CXCL13 and S1P to induce B cell migration as well as adhesion to ICAM‐1 and VCAM‐1. We also show that Pyk2, a tyrosine kinase involved in cytoskeleton rearrangements and B cell migration, is a downstream target of both CXCL13 and S1P signaling and that Rap activation is important for CXCL13 and S1P to stimulate tyrosine phosphorylation of Pyk2, a modification that increases Pyk2 kinase activity. This suggests that the ability of CXCL13 and S1P to direct the trafficking and localization of B cells in vivo may be dependent on Rap activation.
A one‐dimensional model for simulating armouring and erosion on hillslopes: 1. model development and event‐scale dynamics
Authors: Willgoose Garry R. , Sharmeen Saniya
Published: July 2006

This paper presents an erosion model, ARMOUR, which simulates time‐varying runoff, erosion, deposition and surface armour evolution down a hillslope either as a result of a single erosion event or as the cumulative impact of many events over periods up to decades. ARMOUR simulates sediment transport for both cohesive and non‐cohesive soil and dynamically differentiates between ‘transport‐limited’ and ‘source‐limited’ processes. A variety of feasible processes for entrainment of different size classes can be modelled and evaluated against data. The generalized likelihood of uncertainty estimation (GLUE) technique was used to calibrate and validate ARMOUR using data collected during rainfall simulator experiments at two contrasting sites: (1) non‐cohesive stony sediments at Ranger Uranium Mine, Northern Territory, Australia; and (2) cohesive silty sediments at Northparkes Gold Mine, NSW, Australia. The spatial and temporal variations of model predictions within the individual runoff events showed that some entrainment processes could not model the spikes in concentration and subsequent depletion, while the hiding model of Andrews and Parker best simulated the concentration trends for both calibrated and independent runoff events. ARMOUR also successfully captured the coarsening of the surface material, though small, over the duration of the rainfall simulator trials. This was driven by the depletion of the finest size class of the soil. For a constant discharge, ARMOUR simulated higher sediment flux at the start of the storm with the sediment flux and concentration diminishing with time. For natural rainfall a power law relationship between sediment flux and discharge was observed. The calibration exercise showed that sediment concentration and discharge alone are insufficient to calibrate all aspects of the physics, in particular the armour depth. This appears to be because the armouring during the short duration events is driven by depletion of the finest classes of the sediments (diameters less then 62·5 mm), which are not normally measured. Copyright © 2006 John Wiley & Sons, Ltd.
SET complex in serous epithelial ovarian cancer
Authors: Ouellet Véronique , Page Cécile Le , Guyot Marie‐Claude , Lussier Christian , Tonin Patricia N. , Provencher Diane M. , Mes‐Masson Anne‐Marie
Published: July 2006

With low cure rates but increasing diverse treatment options that provide variable remission times, ovarian cancer is increasingly being recognized as a chronic disease. This reality indicates the need for a better understanding of factors influencing disease progression. In a previous global analysis of gene expression, we identified genes differentially expressed when comparing serous epithelial ovarian tumors of low and high malignant potential (grade 0 vs grade 3). In this analysis, 4 out of 5 members of the SET complex, SET, APE1, NM23 and HMGB2, were highly expressed in invasive grade 3 tumors. To further investigate the expression of these genes and the fifth member of the SET complex (pp32), we performed immunohistochemistry, on a tissue array composed of 235 serous tumors of different grades and disease stages. A significant correlation between expression of all SET complex proteins and the tumor differentiation was observed (p < 0.05). When combining all tumors, overexpression of Nm23 (p = 0.04), Set (p = 0.004) and Ape1 (p = 0.004) was associated with the clinical stage of the disease. No marker by itself was associated with prognosis. The combination of a high level of Nm23 in the context of a low level of Set compared to all other combinations of these markers did confer a better prognosis (p = 0.03). When combined, high expression of Hmgb2 and low expression of Ape1 was also associated with patient prognosis (p = 0.05). These findings suggest that a strategy that sums the activities of different partners within a pathway may be more appropriate in designing nomograms for patient stratification. © 2006 Wiley‐Liss, Inc.
Intake of the major carotenoids and the risk of epithelial ovarian cancer in a pooled analysis of 10 cohort studies
Authors: Koushik Anita , Hunter David J. , Spiegelman Donna , Anderson Kristin E. , Buring Julie E. , Freudenheim Jo L. , Goldbohm R. Alexandra , Hankinson Susan E. , Larsson Susanna C. , Leitzmann Michael , Marshall James R. , McCullough Marjorie L. , Miller Anthony B. , Rodriguez Carmen , Rohan Thomas E. , Ross Julie A. , Schatzkin Arthur , Schouten Leo J. , Willett Walter C. , Wolk Alicja , Zhang Shumin M. , Smith‐Warner Stephanie A.
Published: July 2006

Carotenoids, found in fruits and vegetables, have the potential to protect against cancer because of their properties, including their functions as precursors to vitamin A and as antioxidants. We examined the associations between intakes of α‐carotene, β‐carotene, β‐cryptoxanthin, lutein/zeaxanthin and lycopene and the risk of invasive epithelial ovarian cancer. The primary data from 10 prospective cohort studies in North America and Europe were analyzed and then pooled. Carotenoid intakes were estimated from a validated food frequency questionnaire administered at baseline in each study. Study‐specific relative risks (RR) were estimated using the Cox proportional hazards model and then combined using a random‐effects model. Among 521,911 women, 2,012 cases of ovarian cancer occurred during a follow‐up of 7–22 years across studies. The major carotenoids were not significantly associated with the risk of ovarian cancer. The pooled multivariate RRs (95% confidence intervals) were 1.00 (0.95–1.05) for a 600 μg/day increase in α‐carotene intake, 0.96 (0.93–1.03) for a 2,500 μg/day increase in β‐carotene intake, 0.99 (0.97–1.02) for a 100 μg/day increase in β‐cryptoxanthin intake, 0.98 (0.94–1.03) for a 2,500 μg/day increase in lutein/zeaxanthin intake and 1.01 (0.97–1.05) for a 4,000 μg/day increase in lycopene intake. These associations did not appreciably differ by study (p‐values, tests for between‐studies heterogeneity >0.17). Also, the observed associations did not vary substantially by subgroups of the population or by histological type of ovarian cancer. These results suggest that consumption of the major carotenoids during adulthood does not play a major role in the incidence of ovarian cancer. © 2006 Wiley‐Liss, Inc.
History of allergies and risk of glioma in adults
Authors: Schoemaker Minouk J. , Swerdlow Anthony J. , Hepworth Sarah J. , McKinney Patricia A. , van Tongeren Martie , Muir Kenneth R.
Published: July 2006

Epidemiological studies have consistently reported an inverse association between a history of allergic disease and risk of glioma. The reason for this association is unclear, and there is a lack of studies with the detail and size to explore the association in depth. We conducted a UK population‐based case‐control study with 965 glioma cases and 1,716 controls to investigate glioma risk in relation to allergic disease. Risk was reduced in subjects reporting a history of asthma (odds ratio (OR) = 0.71, 95% confidence interval (CI): 0.54–0.92), hay fever (OR = 0.73, 95% CI: 0.59–0.90), eczema (OR = 0.74, 95% CI: 0.56–0.97) and other allergies (OR = 0.65, 95% CI: 0.47–0.90). Risk was reduced for all the main histological groups. There was no significant trend of risk with age, at the onset of each condition, or the number of conditions reported. Risk reductions were strongest for asthma or hay fever with recent onset. Risk in asthmatic subjects was not related to frequency of use of antiasthmatic drugs, but was significantly reduced for use of antiallergenic medication among subjects with hay fever. The study showed an inverse association of glioma risk with allergic disease. Possible reasons for the association, as well as potential immunological aetiology, include confounding, bias and reverse causality. © 2006 Wiley‐Liss, Inc.
Preparation, characterization and cytocompatibility of porous ACP/PLLA composites
Authors: Gao Yanbo , Weng Wenjian , Cheng Kui , Du Piyi , Shen Ge , Han Gaorong , Guan Binggang , Yan Weiqi
Published: July 2006

The purpose of this work was to incorporate amorphous calcium phosphate (ACP) into porous poly(L‐lactic acid) (PLLA), because ACP is capable of fast phase transformation and morphological change in body fluid, such, a desired pore wall surface within bone tissue engineering scaffolds can be created. A highly porous ACP/PLLA composite was prepared by a thermally induced phase separation technique. The results showed that the composite had an interconnected pore structure with 100 μm macropores and 10 μm micropores, and 91% porosity; 40 nm primary particles of ACP were agglomerated to 3 μm aggregates, and the aggregates were homogeneously distributed in pore walls; These aggregates showed to be in situ transformed into bone‐like apatite after 1 h soaking in phosphate buffered saline solution. Human osteoblast‐like cell culture showed that the ACP/PLLA composite had better cell adhesion and alkaline phosphotase activity than pure PLLA. This study demonstrates that the ACP/PLLA composite can enhance cytocompatibility and could act as a promising scaffold for bone tissue engineering. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res, 2006
Nanoimaging for protein misfolding and related diseases
Authors: Lyubchenko Yuri L. , Sherman Simon , Shlyakhtenko Luda S. , Uversky Vladimir N.
Published: July 2006

Misfolding and aggregation of proteins is a common thread linking a number of important human health problems. The misfolded and aggregated proteins are inducers of cellular stress and activators of immunity in neurodegenerative diseases. They might posses clear cytotoxic properties, being responsible for the dysfunction and loss of cells in the affected organs. Despite the crucial importance of protein misfolding and abnormal interactions, very little is currently known about the molecular mechanism underlying these processes. Factors that lead to protein misfolding and aggregation in vitro are poorly understood, not to mention the complexities involved in the formation of protein nanoparticles with different morphologies (e.g., the nanopores) in vivo. A better understanding of the molecular mechanisms of misfolding and aggregation might facilitate development of the rational approaches to prevent pathologies mediated by protein misfolding. The conventional tools currently available to researchers can only provide an averaged picture of a living system, whereas much of the subtle or short‐lived information is lost. We believe that the existing and emerging nanotools might help solving these problems by opening the entirely novel pathways for the development of early diagnostic and therapeutic approaches. This article summarizes recent advances of the nanoscience in detection and characterization of misfolded protein conformations. Based on these findings, we outline our view on the nanoscience development towards identification intracellular nanomachines and/or multicomponent complexes critically involved in protein misfolding. J. Cell. Biochem. © 2006 Wiley‐Liss, Inc.
A Kirkwood‐Buff derived force field for amides
Authors: Kang Myungshim , Smith Paul E.
Published: July 2006

A force field for the computer simulation of aqueous solutions of amides is presented. The force field is designed to reproduce the experimentally observed density and Kirkwood–Buff integrals for N‐methylacetamide (NMA), allowing for an accurate description of the NMA activity. Other properties such as the translational diffusion constant and heat of mixing are also well reproduced. The force field is then extended to include N,N′‐dimethylacetamide and acetamide with good success. Analysis of the simulations of low concentrations of NMA in water indicates a high degree of solvation with only 15% of the NMA molecules involved in solute–solute hydrogen bonding. There is only a weak angular dependence of the solute–solute hydrogen bonding interaction with a minimum at an angle of 65° for the NH and CO dipole vectors. The models presented here provide a basis for an accurate force field for peptides and proteins. © 2006 Wiley Periodicals, Inc. J Comput Chem 27: 1477–1485, 2006
Bone‐specific heparan sulfates induce osteoblast growth arrest and downregulation of retinoblastoma protein
Authors: Manton Kerry J. , Sadasivam Murali , Cool Simon M. , Nurcombe Victor
Published: July 2006

The heparan sulfate (HSs) sugars of the extracellular matrix (ECM) play a key role during both development and wound repair in regulating the flow of growth and adhesive factors across their cell surface receptors. The aim of this study was to assess the structural and functional differences of HS chains extracted from the conditioned media (soluble), cell surface, and ECM of primary human osteoblast cultures, and to analyze their effects on osteoblast cell growth. HS chains from these compartments were characterized through a combination of enzymatic degradation, anion exchange chromatography, and molecular sieving. Although the chains were all approximately the same size, they varied systematically in their sulfate content, suggesting differences in their protein‐binding domains. When added to pre‐confluent hFOB1.19 osteoblast cultures, HS doses exceeding 500 ng/ml inhibited proliferation, without affecting viability, irrespective of their origin. Furthermore, HS doses of 500 ng/ml also downregulated retinoblastoma, Cyclin A and CDK1 protein expression, indicating that high doses of osteoblast HS negatively regulate cell cycle, resulting in growth arrest; when high doses of HS were withdrawn after a prolonged period, linear cell growth was reestablished. Thus, despite differences in sulfation, HS from either the soluble, cell surface, or matrix compartments of primary human osteoblast cultures are functionally similar with respect to their effects on growth. Binding assays revealed that the HS chains bound TGFβ1, a known inhibitor of osteoprogenitor growth, at higher affinity than a suite of other bone‐related, heparin‐binding growth factors. Overcoming such sugar‐mediated inhibition may prove important for wound repair. J. Cell. Physiol. 209: 219–229, 2006. © 2006 Wiley‐Liss, Inc.
Asylum‐seekers and refugees: a structuration theory analysis of their experiences in the UK
Authors: Healey Ruth L.
Published: July 2006

Much of the literature on asylum‐seekers and refugees tends to be atheoretical. This article uses ideas from Giddens' structuration theory as a conceptual framework to analyse the voices of a group of asylum‐seekers and refugees. The empirical database consists of semi‐structured interviews with 18 asylum‐seekers and refugees living in the UK from a wide range of countries, including Ethiopia, Kenya, Poland, Somalia and the Yemen. The study shows that the experiences of asylum‐seekers and refugees are impacted by both structural and individual agency factors. The former, it is argued, consist of public and political reaction towards the increase in the number of asylum applications, while the latter include asylum‐seeker and refugee experiences of specific places and people which can create social networks. Structural factors had the greatest impact upon the integration of the participants into the host society. The nature of the experiences of asylum‐seekers and refugees can influence the way they feel about their position in the host society. For example, negative experiences of the UK can reduce their sense of security in the society, whereas positive experiences can increase their feelings of comfort. Structuration theory conceptualises how asylum‐seekers and refugees utilise coping strategies to raise their comfort level in the host country. Copyright © 2006 John Wiley & Sons, Ltd.
Theory of spintronic materials
Authors: Chelikowsky James R. , Kaxiras Efthimios , Wentzcovitch Renata M.
Published: July 2006

The ability to manipulate and understand spin polarized materials is a key to constructing spintronic devices, i.e., devices in which the electron'sspinand charge are both utilized. Here we review computational methods for predicting the properties of spin‐polarized materials at the macro‐ and nano‐limits, and at interfaces. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The hazards to practitioners of obstetric and gynecological ultrasound
Authors: Hackmon R. , Sheiner E. , Barnhard Y. , Beer R. , Meizner I.
Published: July 2006

Objectives

To investigate the specific complaints of physicians and technicians performing obstetric and gynecological ultrasound.

Methods

This was a cross‐sectional retrospective survey. Questionnaires were distributed to members of the Israeli Society of Gynecological Ultrasound, including questions on gender and profession, number and type of scans performed, pain related to profession and any therapy undergone. Statistical analysis included chi‐square or Fisher's exact test, Student's t‐test, Pearson's correlation coefficient and logistic regression.

Results

Joint pain was reported by 51.7% (30/58) of the technicians compared with 25.3% (19/75) of the physicians (P = 0.002). It was more common in females than in males (P = 0.05) and it was more common among those who performed transabdominal sonography more frequently than they did transvaginal sonography (P = 0.004). There was a significant association between performing transabdominal ultrasound and back pain (P = 0.05). Although females reported pain more frequently, the rate of surgical procedures was higher among males (P < 0.05).

Conclusions

A technician is 3.5 times more likely to report joint pain than is a physician. Transabdominal sonography is a risk for both joint and back pain. There may be gender differences in pain perception. Copyright © 2006 ISUOG. Published by John Wiley & Sons, Ltd.
Ductus venosus blood flow alterations in fetuses with obstructive lesions of the right heart
Authors: Berg C. , Kremer C. , Geipel A. , Kohl T. , Germer U. , Gembruch U.
Published: July 2006

Objective

To assess the impact of isolated lesions of the fetal right heart on ductus venosus (DV) blood flow profiles.

Methods

Retrospective evaluation of DV blood flow profiles in 83 fetuses with isolated right‐sided cardiac lesions. Cases were divided into two groups. Group A had right‐sided cardiac lesions associated with a large ventricular septal defect that equalized interventricular pressures (double outlet right ventricle (n = 12), tetralogy of Fallot (n = 19), pulmonary atresia (n = 5)). Group B had right‐sided cardiac lesions with obstruction of the inflow (tricuspid atresia with ventricular septal defect (n = 14)) or obstruction of the outflow with intact ventricular septum (Ebstein's anomaly (n = 13), pulmonary stenosis (n = 13) and pulmonary atresia (n = 7)). Comparisons were made with 585 uneventful singleton pregnancies and previously published normative values.

Results

Fetuses in Group B had significantly higher rates of abnormal DV flow profiles compared to Group A and controls (P < 0.01). Conversely, there were no significant differences concerning DV parameters between fetuses in Group A and controls. Despite these different DV flow characteristics, there were no significant differences concerning signs of cardiac failure and/or survival to the perinatal period between the two groups.

Conclusions

Right‐sided cardiac lesions with obstruction of the inflow or outflow with intact ventricular septum are significantly associated with abnormally high pulsatilities in the DV and may even cause a reversal of flow during atrial contraction. These changes do not necessarily indicate cardiac failure, as they are primarily attributable to the special hemodynamics of the cardiac defect. Copyright © 2006 ISUOG. Published by John Wiley & Sons, Ltd.
Tonsillitis to mediastinitis
Authors: Collin J , Beasley N
Published: July 2006

Parapharyngeal abscess secondary to quinsy is a well understood complication; however, its incidence has significantly declined following early use of effective antibiotics. Tracking of infection from the parapharyngeal space through the anatomical planes to cause mediastinitis has a significant mortality rate and requires early detection and aggressive management. A case of quinsy leading to mediastinitis, pericarditis and pleural effusions is presented. It highlights the potentially life-threatening complications of a commonly encountered ENT problem.
Xu Jilin and the Thought Work of China's Public Intellectuals
Authors: Cheek Timothy
Published: July 2006

This article takes recent theoretical essays by Shanghai scholar and public intellectual, Xu Jilin, and other scholars of the history of thought and culture (sixiang wenhua shi) as a case study of efforts by intellectuals in the People's Republic of China to define and promote a role as public intellectuals separate from the party-state. This analysis suggests that political liberalism is used in such intellectual discourse to explain the social experience of intellectuals in China today and to promote a renewed public role for them. This public intellectual discourse is characterized by the continued privileging of sixiang (thought), by the naturalizing of foreign theories about liberalism, and by the use of such thought work to argue for a renewed public role for intellectuals as interpreters of public issues rather than as legislators of public values.
Upper mantle velocity‐temperature conversion and composition determined from seismic refraction and heat flow
Authors: Perry H. K. C. , Jaupart C. , Mareschal J.‐C. , Shapiro N. M.
Published: July 2006

We compile upper mantle Pn velocities from seismic refraction/wide‐angle reflection surveys in the southern Superior Province of the Canadian Shield and compare them with temperatures at the Moho deduced from heat flow data. Calculated Moho temperatures and Pn velocities correlate well, showing that in this area, Pn depends primarily on temperature. The obtained values of ∂V(Pn)/∂T depend weakly on the assumed value of Moho heat flow and are on the order of −6.0 × 10−4 ± 10% km s−1 K−1, within the range of temperature derivatives obtained in laboratory studies of ultramafic rocks. Comparison between observed Pn velocities and predicted values for several mineralogical models at Moho temperatures allows constraints on both the Moho heat flow and the shallow mantle composition. For all Moho heat flows, undepleted (clinopyroxene‐rich) mantle compositions do not allow a good fit to the data. For depleted mantle compositions, temperatures consistent with the observed Pn velocities correspond to values of Moho heat flow larger than 12 mW m−2. For our preferred Moho heat flow of 15 mW m−2, the best fit mantle composition is slightly less depleted than models for average Archean subcontinental lithospheric mantle. This may be due to rejuvenation by melt‐related metasomatism during the Keweenawan rifting event. The similarity in Pn − T conversion factors estimated from this empirical large‐scale geophysical study and those from laboratory data provides confidence in the absolute temperature values deduced from heat flow measurements and seismic studies.
Impacts of tides and atmospheric forcing variability on dissolved oxygen in the subarctic North Pacific
Authors: Andreev Andrey G. , Baturina Victoria I.
Published: July 2006

The impacts of variations in wind‐forcing and the 18.6‐year period tidal cycle on the concentration of dissolved oxygen (DO) in the intermediate waters of the subarctic North Pacific were analyzed. Our results demonstrate that the interannual changes of DO on isopycnal surfaces in the intermediate waters of the western subarctic Pacific can be described very accurately by a linear combination of the intensity of the Aleutian Low pressure system (North Pacific Index), the zonal wind stress (45°N–52°N, 165°E–170°W) in winter, and an annually averaged cubic of tidal amplitude for the central Aleutian and northern Kuril regions. The residual signal shows a good correlation with the temporal variations of DO in the Alaska Gyre.
Optical Spectrograph and Infra‐Red Imaging System (OSIRIS) observations of mesospheric OH A2Σ+‐X2Π 0‐0 and 1‐1 band resonance emissions
Authors: Gattinger R. L. , Degenstein D. A. , Llewellyn E. J.
Published: July 2006

Although only a minor species, the OH molecule plays an important role in the photochemical control of mesospheric ozone density and has been the target of a number of observational programs, principally through the OH A2Σ+‐X2Π 0‐0 band emission at 308 nm. This emission band arises from solar resonance fluorescence excitation of OH X2Π ground state molecules, and its observation is complicated by the presence of an underlying atmospheric Rayleigh scattering spectrum. We show that the OH A2Σ+‐X2Π 0‐0 band emission has been reliably and routinely detected with the moderately low, 0.9 nm, spectral resolution Optical Spectrograph and Infra‐Red Imaging System (OSIRIS) limb scanning spectrograph. Changes in upper mesospheric water vapor observed by the Halogen Occultation Experiment (HALOE) are readily detected as changes in the OH density profiles seen by OSIRIS. Altitude profiles of OH density in the middle and upper mesosphere are in good agreement with model results that incorporate coordinated HALOE water vapor measurements. The agreement is within the HALOE and OSIRIS error limits when the recommended standard reaction rates are assumed. Conversely, model calculations of OH density using the revised reaction rates proposed to explain the Middle Atmosphere High‐Resolution Spectrograph Investigation (MAHRSI) OH profiles typically fall outside the observed OSIRIS error limits. The OSIRIS results suggest that the probable difference between the observed and modeled OH densities is less than 15% from 55 to 80 km. Diurnal and seasonal OH variations observed by OSIRIS are in good agreement with model predictions. These successful comparisons suggest that the OSIRIS OH database, spanning more than 4 years of operation and broad ranges of latitude and local time, can contribute significantly to studies of OH photochemistry and upper mesospheric water vapor.
Current sheets at low altitudes in the Martian magnetotail
Authors: Halekas J. S. , Brain D. A. , Lillis R. J. , Fillingim M. O. , Mitchell D. L. , Lin R. P.
Published: July 2006

We present observations of 1116 current sheet crossings in the Martian magnetotail during one Martian year, as identified from magnetic field rotations measured by Mars Global Surveyor (MGS) at ∼400 km altitude and 2 am local time. Crossings are observed everywhere except above strong crustal fields, and many occur in clusters, with preferred locations varying as a function of season and IMF draping direction. Magnetic polarities are consistent with day‐side IMF draping directions and a two‐lobe induced magnetotail. Energetic “plasma sheet” electrons are often absent, implying that currents can be carried by ions or low‐energy electrons, with thicknesses of <∼100 km arguing for electrons. The presence of a thin current sheet at low altitudes, with specific seasons and IMF directions favored for some geographic locations, implies that reconnection between crustal fields and the draped IMF may play an important role in its formation and location.
Nonlinear optical susceptibility of deformed achiral carbon nanotubes studied from first-principles calculations
Authors: Zhou Jian , Weng Hongming , Wu Gang , Dong Jinming
Published: July 2006

The second harmonic generation (SHG) coefficients of the deformed single-walled carbon nanotubes (SWNTs) have been calculated from the density functional theory in the local density approximation. The obtained results show that their nonlinear responses are very sensitive to the deformation degree and the helicity of the SWNTs, as well as the type of applied strains. More importantly and interestingly, the SHG can be induced in the armchair or zigzag nanotubes under torsional strain, making them promising nonlinear optical materials controllable by applied strains.
Resonant photoemission study of single-strand deoxyribonucleic acid
Authors: Wang Li , Zhang Ke-Qin , Gao Xingyu , Liu Xiang-Yang , Wee Andrew T. S.
Published: July 2006

The electronic structure of single-strand DNA was studied by resonant photoemission spectroscopy at C1s and N1s resonances to understand the charge transfer process in DNA. The intensity enhancements of valence electrons were clearly observed at both C1s and N1s resonances although they emerged at different regions of the valence band at each resonance. These observations provide direct evidence for the localized nature of the unoccupied states in the nucleobases and backbone, and support the validity of the charge hopping model in long-range charge migration in DNA.