bluuebunny/crossref_metadata_2025 huggingface dataset:
Optical and electronic properties of thermoelectric Zn4Sb3 across the low-temperature phase transitions
Authors: Litvinchuk A. P. , Lorenz B. , Chen Feng , Nylén J. , Häussermann U. , Lidin Sven , Wang Limin , Guloy Arnold M.
Published: May 2007

Using infrared reflection spectroscopy the authors show that the phase transitions from disordered high temperature β-Zn4Sb3 into the increasingly higher ordered and complex structured low-temperature phases α and α′ are accompanied by a significant increase in the free charge carrier density and a concomitant increase of the effective scattering rate.
Electron effective mass and phonon modes in GaAs incorporating boron and indium
Authors: Hofmann T. , Schubert M. , Leibiger G. , Gottschalch V.
Published: May 2007

The strain-free boron- and indium-containing GaAs compounds are promising candidates for III-V semiconductor solar cell absorber materials with lattice match to GaAs, for which experimental data of the electronic band structure are widely unknown. For nondegenerate, silicon-doped, n-type B0.03In0.06Ga0.91As with band-gap energy of 1.36eV, determined by near-infrared ellipsometry, a strong increase of the electron effective mass of 44% in B0.03In0.06Ga0.91As compared to In0.06Ga0.94As is obtained from far-infrared magneto-optic generalized ellipsometry studies. The authors thereby obtain the vibrational lattice mode behavior. For BAs, an experimentally obscure compound, the curvature of the Γ-point conduction band thus extrapolates to the free electron mass.
Surface heterostructure nanomechanical actuators with atomic resolution
Authors: Makowski Jan D. , Talghader Joseph J.
Published: May 2007

A continuously tunable vertical actuator with subnanometer resolution is presented. It consists of a heterostructure cantilever which has collapsed over a 125nm thick nanogap. Its operating principle relies on the temperature dependence of the adhesion energy between two InGaAs surface quantum wells. Deflections from −17to5nm with a precision better than three atomic layers have been measured.
Photonic crystal effect on light emission from InGaN∕GaN multi-quantum-well structures
Authors: Kim Keunjoo , Choi Jaeho , Jeon Sang Cheol , Kim Jin Soo , Lee Hee Mok
Published: May 2007

Triangular hole arrays with nanoscaled lattice constants of 230 and 460nm were fabricated on a p-type GaN epitaxial layer grown on an InGaN∕GaN multi-quantum-well light emitting diode structure by metal-organic chemical vapor deposition. The hole geometries of dry-etched thin slabs for triangular lattice constants of 230 and 460nm possessed diameters of 223 and 218nm at the surface, and 108 and 76nm at the bottom, with depths of 31 and 27nm, respectively. The hole array with a lattice constant of 230nm enhances photoluminescence intensity at wavelengths of 364 and 406nm, but reduces light extraction at a wavelength of 450nm, which indicates destructive surface diffraction correlated with light scattering in the photonic crystal structure.
Intersubband absorption with different sublevel couplings in [(CdS∕ZnSe∕BeTe)∕(ZnSe∕BeTe)] double quantum wells
Authors: Cong G. W. , Akimoto R. , Akita K. , Hasama T. , Ishikawa H.
Published: May 2007

The authors demonstrated the strong sublevel coupling on the intersubband absorption at telecommunication wavelengths in asymmetric II-VI double quantum wells consisting of a deep CdS well and a shallow ZnSe well coupled by a 1-monolayer-thick BeTe barrier. With increasing ZnSe well thickness, the sublevel coupling between excited states first increases to a maximum and then decreases, which results in a transition energy anticrossing and a reverse intensity evolution for e1-e2 and e1-e3 transitions. These results are in good agreement with the self-consistent Schrödinger-Poisson calculation. For optical switch applications, the sublevel-coupling-dependent relaxation time could be increased to lower the switching energy.
Self-oscillating electroactive polymer actuator
Authors: Kim Doyeon , Kim Kwang J. , Tak Yongsuk , Pugal Deivid , Park Il-Seok
Published: May 2007

To drive the electroactive polymer (EAP) materials and subsequently control their strain generation, the need for power electronics and driving circuits has been eminent. In this letter the authors demonstrate a spontaneous actuation of an electroactive polymer that requires only dc power to produce its ac responses. Such a dc-to-ac response of the EAP was achieved by the deposition of an effective electrocatalyst, i.e., platinum, on an ionomer, Nafion™. The coated ionomer was immersed into an acidic formaldehyde solution. An applied dc voltage will produce current oscillations in the system, and therefore oscillating bending of the actuator.
Introducing groundwater physics
Authors: Anderson Mary P.
Published: May 2007

Studied as early as the mid-19th century, the physics of water beneath Earth's surface is the basis of groundwater hydrology, a multifaceted discipline that continues to challenge theorists and experimentalists alike.
Defeating Cane Diseases: Plant Pathologists and the Development of Disease Control Strategies in the Australian Sugar Industry, 1920 - 1950
Authors: Griggs Peter
Published: May 2007

Between 1920 and 1950, the Queensland sugar industry was troubled by many of the diseases that plagued sugar cane, often in serious proportions. Financial losses from these disease outbreaks in the 1920s prompted the Colonial Sugar Refining Company (CSR) and the Queensland Bureau of Sugar Experiment Stations (BSES) to employ university-trained plant pathologists who undertook research into identifying the diseases, understanding their etiology and devising control strategies to reduce their impact. Archival records, annual reports of both organizations and published scientific papers are used to reconstruct the programmes of research undertaken into these diseases. Control strategies developed as a result of this research included restrictions on the movement of cane plants, the establishment of quarantine districts, use of disease-free planting material, pre-treatment of planting material with hot water and/or solutions of organic mercurial fungicides, and 'roguing' of diseased cane plants. Consequently, by 1950, gumming, Fiji and downy mildew diseases — three of the most troublesome cane diseases in Australia — had been virtually eliminated in sugar-producing districts.
Alan Buchanan Wardrop 1921 - 2003
Authors: Williamson Richard E. , Higgins Huntly G. , Stone Bruce A.
Published: May 2007

Alan Buchanan Wardrop was one of Australia's most distinguished students of plant cell wall ultra-structure who made major contributions to our understanding of the structure of secondary walls and of how that structure affected the industrial uses of wood fibres. His work integrated information from observations with polarized light, X-rays and electron microscopy. Joining the Forest Products Division of Australia's Council for Scientific and Industrial Research in 1945, he became Foundation Professor of Biological Sciences at La Trobe University, Melbourne, in 1965.
Many Beautiful Things: Colonial Botanists' Accounts of the North Queensland Rainforests
Authors: Sanderson Rachel
Published: May 2007

Colonial botanists played an important role in both elucidating and reshaping the nature of the North Queensland rainforests between 1860 and 1915. The Government Botanist of Victoria, Ferdinand von Mueller, was the first to begin to document the plant life of North Queensland. In 1859, on separation from New South Wales, Queensland's first Colonial Botanist was appointed to the Brisbane Botanic Gardens; this role was filled initially by Walter Hill, then by Frederick Manson Bailey.They were based at a distance from the northern rainforests and largely relied on local collectors to supply them with specimens that they would then identify, name and describe. They were also part of a network that assisted in the introduction of plants to North Queensland from other tropical locations for acclimatization purposes, and they worked to promote the development of tropical agriculture in the region. Colonial botanists not only promoted the settlement of rainforest areas and utilization of rainforest species, they also recorded and commented on the associated processes of environmental change that they observed.
Conserved domain structure of pentatricopeptide repeat proteins involved in chloroplast RNA editing
Authors: Okuda Kenji , Myouga Fumiyoshi , Motohashi Reiko , Shinozaki Kazuo , Shikanai Toshiharu
Published: May 2007

The pentatricopeptide repeat (PPR) proteins form one of the largest families in higher plants and are believed to be involved in the posttranscriptional processes of gene expression in plant organelles. It has been shown by using a genetic approach focusing on NAD(P)H dehydrogenase (NDH) activity that a PPR protein CRR4 is essential for a specific RNA editing event in chloroplasts. Here, we discovered
Arabidopsis crr21
mutants that are specifically impaired in the RNA editing of the site 2 of
ndhD
(ndhD-2), which encodes a subunit of the NDH complex. The
CRR21
gene encodes a member of the PPR protein family. The RNA editing of ndhD-2 converts the Ser-128 of NdhD to leucine. In
crr21
, the activity of the NDH complex is specifically impaired, suggesting that the Ser128Leu change has important consequences for the function of the NDH complex. Both CRR21 and CRR4 belong to the E+ subgroup in the PLS subfamily that is characterized by the presence of a conserved C-terminal region (the E/E+ domain). This E/E+ domain is highly conserved and exchangeable between CRR21 and CRR4, although it is not essential for the RNA binding. Our results suggest that the E/E+ domain has a common function in RNA editing rather than of recognizing specific RNA sequences.
Essential roles of the bHLH transcription factor Hrt2 in repression of atrial gene expression and maintenance of postnatal cardiac function
Authors: Xin Mei , Small Eric M. , van Rooij Eva , Qi Xiaoxia , Richardson James A. , Srivastava Deepak , Nakagawa Osamu , Olson Eric N.
Published: April 2007

The basic helix–loop–helix transcriptional repressor Hairy-related transcription factor 2 (Hrt2) is expressed in ventricular, but not atrial, cardiomyocytes, and in endothelial and vascular smooth muscle cells. Mice homozygous for a null mutation of
Hrt2
die perinatally from a spectrum of cardiac abnormalities, raising questions about the specific functions of this transcriptional regulator in individual cardiac cell lineages. Using a conditional
Hrt2
null allele, we show that cardiomyocyte-specific deletion of
Hrt2
in mice results in ectopic activation of atrial genes in ventricular myocardium with an associated impairment of cardiac contractility and a unique distortion in morphology of the right ventricular chamber. Consistent with the atrialization of ventricular gene expression in
Hrt2
mutant mice, forced expression of
Hrt2
in atrial cardiomyocytes is sufficient to repress atrial cardiac genes. These findings reveal a ventricular myocardial cell-autonomous function for Hrt2 in the suppression of atrial cell identity and the maintenance of postnatal cardiac function.
Stabilization of RAD-51–DNA filaments via an interaction domain in
Caenorhabditis elegans
BRCA2
Authors: Petalcorin Mark I. R. , Galkin Vitold E. , Yu Xiong , Egelman Edward H. , Boulton Simon J.
Published: May 2007

Mutations in BRCA2 predispose individuals to breast cancer, a consequence of the role of BRCA2 in DNA repair. Human BRCA2 interacts with the recombinase RAD51 via eight BRC repeats. Controversy has existed, however, about whether the BRC interactions are primarily with RAD51 monomers or with the RAD51–DNA helical polymer, and whether there is a single interaction or multiple ones. We show here that the single BRC motif in the
Caenorhabditis elegans
BRCA2 homolog, CeBRC-2, contains two different RAD-51-binding regions. One of these regions binds only weakly to RAD-51–DNA filaments but strongly to RAD-51 alone and corresponds to the part of human BRC4 crystallized with RAD51. Injection of a peptide corresponding to this region into worms inhibits the normal formation of RAD-51 foci in response to ionizing radiation (IR). Conversely, peptides corresponding to the second region bind strongly to RAD-51–DNA filaments but do not bind to RAD-51 alone. Three-dimensional reconstructions from electron micrographs show that this peptide binds to the RAD-51 N-terminal domain, which has been shown to have a regulatory function. Injection of this peptide into worms before IR leads to a dramatic increase and persistence of IR-induced RAD-51 foci. This peptide also inhibits the RAD-51 ATPase activity, required for filament depolymerization. These results support a model where an interaction with RAD-51 alone is likely involved in filament nucleation, whereas a second independent interaction is involved in stabilization of RAD-51 filaments by BRCA2. The multiple interactions between BRCA2-like molecules and RAD51 provide insights into why mutations in BRCA2 lead to cancer.
Inhibition of Integrin-mediated Crosstalk with Epidermal Growth Factor Receptor/Erk or Src Signaling Pathways in Autophagic Prostate Epithelial Cells Induces Caspase-independent Death
Authors: Edick Mathew J. , Tesfay Lia , Lamb Laura E. , Knudsen Beatrice S. , Miranti Cindy K.
Published: May 2007

In vivo in the prostate gland, basal epithelial cells adhere to laminin 5 (LM5) via α3β1 and α6β4 integrins. When placed in culture primary prostate basal epithelial cells secrete and adhere to their own LM5-rich matrix. Adhesion to LM5 is required for cell survival that is dependent on integrin-mediated, ligand-independent activation of the epidermal growth factor receptor (EGFR) and the cytoplasmic tyrosine kinase Src, but not PI-3K. Integrin-mediated adhesion via α3β1, but not α6β4 integrin, supports cell survival through EGFR by signaling downstream to Erk. PC3 cells, which do not activate EGFR or Erk on LM5-rich matrices, are not dependent on this pathway for survival. PC3 cells are dependent on PI-3K for survival and undergo caspase-dependent death when PI-3K is inhibited. The death induced by inhibition of EGFR or Src in normal primary prostate cells is not mediated through or dependent on caspase activation, but depends on the induction of reactive oxygen species. In addition the presence of an autophagic pathway, maintained by adhesion to matrix through α3β1 and α6β4, prevents the induction of caspases when EGFR or Src is inhibited. Suppression of autophagy is sufficient to induce caspase activation and apoptosis in LM5-adherent primary prostate epithelial cells.
Nitric Oxide Signaling Is Disrupted in the Yeast Model for Batten Disease
Authors: Osório Nuno S. , Carvalho Agostinho , Almeida Agostinho J. , Padilla-Lopez Sérgio , Leão Cecília , Laranjinha João , Ludovico Paula , Pearce David A. , Rodrigues Fernando
Published: May 2007

The juvenile form of neuronal ceroid lipofuscinoses (JNCLs), or Batten disease, results from mutations in the CLN3 gene, and it is characterized by the accumulation of lipopigments in the lysosomes of several cell types and by extensive neuronal death. We report that the yeast model for JNCL (btn1-Δ) that lacks BTN1, the homologue to human CLN3, has increased resistance to menadione-generated oxidative stress. Expression of human CLN3 complemented the btn1-Δ phenotype, and equivalent Btn1p/Cln3 mutations correlated with JNCL severity. We show that the previously reported decreased levels of l-arginine in btn1-Δ limit the synthesis of nitric oxide (·NO) in both physiological and oxidative stress conditions. This defect in ·NO synthesis seems to suppress the signaling required for yeast menadione-induced apoptosis, thus explaining btn1-Δ phenotype of increased resistance. We propose that in JNCL, a limited capacity to synthesize ·NO directly caused by the absence of Cln3 function may contribute to the pathology of the disease.
Coordination of Hpr1 and Ubiquitin Binding by the UBA Domain of the mRNA Export Factor Mex67
Authors: Hobeika Maria , Brockmann Christoph , Iglesias Nahid , Gwizdek Carole , Neuhaus David , Stutz Françoise , Stewart Murray , Divita Gilles , Dargemont Catherine
Published: May 2007

The ubiquitin-associated (UBA) domain of the mRNA nuclear export receptor Mex67 helps in coordinating transcription elongation and nuclear export by interacting both with ubiquitin conjugates and specific targets, such as Hpr1, a component of the THO complex. Here, we analyzed substrate specificity and ubiquitin selectivity of the Mex67 UBA domain. UBA-Mex67 is formed by three helices arranged in a classical UBA fold plus a fourth helix, H4. Deletion or mutation of helix H4 strengthens the interaction between UBA-Mex67 and ubiquitin, but it decreases its affinity for Hpr1. Interaction with Hpr1 is required for Mex67 UBA domain to bind polyubiquitin, possibly by inducing an H4-dependent conformational change. In vivo, deletion of helix H4 reduces cotranscriptional recruitment of Mex67 on activated genes, and it also shows an mRNA export defect. Based on these results, we propose that H4 functions as a molecular switch that coordinates the interaction of Mex67 with ubiquitin bound to specific substrates, defines the selectivity of the Mex67 UBA domain for polyubiquitin, and prevents its binding to nonspecific substrates.
A novel optical coherence tomography-based micro-indentation technique for mechanical characterization of hydrogels
Authors: Yang Ying , Bagnaninchi Pierre O , Ahearne Mark , Wang Ruikang K , Liu Kuo-Kang
Published: May 2007

Depth-sensing micro-indentation has been well recognized as a powerful tool for characterizing mechanical properties of solid materials due to its non-destructive approach. Based on the depth-sensing principle, we have developed a new indentation method combined with a high-resolution imaging technique, optical coherence tomography, which can accurately measure the deformation of hydrogels under a spherical indenter at constant force. The Hertz contact theory has been applied for quantitatively correlating the indentation force and the deformation with the mechanical properties of the materials. Young's moduli of hydrogels estimated by the new method are comparable with those measured by conventional depth-sensing micro-indentation. The advantages of this new method include its capability to characterize mechanical properties of bulk soft materials and amenability to perform creeping tests. More importantly, the measurement can be performed under sterile conditions allowing non-destructive,
in situ
and real-time investigations on the changes in mechanical properties of soft materials (e.g. hydrogel). This unique character can be applied for various biomechanical investigations such as monitoring reconstruction of engineered tissues.
Hypoxia and the antipredator behaviours of fishes
Authors: Domenici P , Lefrançois C , Shingles A
Published: May 2007

Hypoxia is a phenomenon occurring in marine coastal areas with increasing frequency. While hypoxia has been documented to affect fish activity and metabolism, recent evidence shows that hypoxia can also have a detrimental effect on various antipredator behaviours. Here, we review such evidence with a focus on the effect of hypoxia on fish escape responses, its modulation by aquatic surface respiration (ASR) and schooling behaviour. The main effect of hypoxia on escape behaviour was found in responsiveness and directionality. Locomotor performance in escapes was expected to be relatively independent of hypoxia, since escape responses are fuelled anaerobically. However, hypoxia decreased locomotor performance in some species (Mugilidae) although only in the absence of ASR in severe hypoxia. ASR allows fish to show higher escape performance than fish staying in the water column where hypoxia occurs. This situation provides a trade-off whereby fish may perform ASR in order to avoid the detrimental effects of hypoxia, although they would be subjected to higher exposure to aerial predation. As a result of this trade-off, fishes appear to minimize surfacing behaviour in the presence of aerial predators and to surface near shelters, where possible.

For many fish species, schooling can be an effective antipredator behaviour. Severe hypoxia may lead to the disruption of the school unit. At moderate levels, hypoxia can increase school volume and can change the shuffling behaviour of individuals. By altering school structure and dynamics, hypoxia may affect the well functioning of schooling in terms of synchronization and execution of antipredator manoeuvres. School structure and volume appear to be the results of numerous trade-offs, where school shape may be dictated by the presence of predators, the need for energy saving via hydrodynamic advantages and oxygen level.

The effects of hypoxia on aquatic organisms can be taxon specific. While hypoxia may not necessarily increase the vulnerability of fish subject to predation by other fish (since feeding in fish also decreases in hypoxia), predators from other taxa such as birds, jellyfish or aquatic mammals may take advantage of the detrimental effects of hypoxia on fish escape ability. Therefore, the effect of hypoxia on fish antipredator behaviours may have major consequences for the composition of aquatic communities.
Consequences of thermal acclimation for the mating behaviour and swimming performance of female mosquito fish
Authors: Wilson Robbie S , Condon Catriona H.L , Johnston Ian A
Published: May 2007

The mating system of eastern mosquito fish (Gambusia holbrooki) is dominated by male sexual coercion, where all matings are forced and females never appear to cooperate and actively avoid all attempts. Previous research has shown that maleG. holbrookioffer a model system for examining the benefits of reversible thermal acclimation for reproductive success, but examining the benefits to female avoidance behaviour has been difficult. In this study, we examined the ability of non-male-deprived femaleG. holbrookito avoid forced–coercive matings following acclimation to either 18 or 30°C for six weeks (12 h light : 12 h dark photoperiod). Thermal acclimation of burst and sustained swimming performance was also assessed, as these traits are likely to underlie their ability to avoid forced matings. There was no influence of thermal acclimation on the burst swimming performance of femaleG. holbrookiover the range 18–30°C; however, sustained swimming performance was significantly lower in the warm- than the cool-acclimation group. For mating behaviour, we tested the hypothesis that acclimation would enhance the ability of femaleG. holbrookito avoid forced matings at their host acclimation temperature relative to females acclimated to another environment. However, our hypothesis was not supported. The rate of copulations was almost three times greater for females acclimated to 30°C than 18°C when tested at 30°C, indicating that they possess the ability to alter their avoidance behaviour to ‘allow’ more copulations in some environments. Coupled with previous studies, femaleG. holbrookiappear to have greater control on the outcome of coercive mating attempts than previously considered and can alter their propensity to receive forced matings following thermal acclimation. The significance of this change in female mating-avoidance behaviours with thermal acclimation remains to be explored.
Accounting for a Shift in Term Structure Behavior with No‐Arbitrage and Macro‐Finance Models
Authors: RUDEBUSCH GLENN D. , WU TAO
Published: May 2007

This paper examines a shift in the dynamics of the term structure of interest rates in the United States during the mid‐1980s. We document this shift using standard interest rate regressions and using dynamic, affine, no‐arbitrage models estimated for the pre‐ and post‐shift subsamples. The term structure shift largely appears to be the result of changes in the pricing of risk associated with a “level” factor. Using a macro‐finance model, we suggest a link between this shift in term structure behavior and changes in the dynamics and risk pricing of the Federal Reserve's inflation target as perceived by investors.
Interest Rate Risk and the Forward Premium Anomaly in Foreign Exchange Markets
Authors: WU SHU
Published: May 2007

This paper shows that even adjusted for the time‐varying risk premiums implied by the yield curves across countries, uncovered interest parity is still strongly rejected by the data. Moreover, factors that predict the excess bond returns are found not significant at all in predicting the foreign exchange returns. These results reject the joint restrictions on the exchange rate and interest rates imposed by dynamic term‐structure models, suggesting that foreign exchange markets and bond markets may not be fully integrated and we have to look beyond interest rate risk in order to understand the exchange rate anomaly.
Inventory Dynamics and Business Cycles: What Has Changed?
Authors: McCARTHY JONATHAN , ZAKRAJŠEK EGON
Published: May 2007

To what extent can information‐technology led improvements in inventory management account for the apparent moderation of economic fluctuations in the United States since the mid‐1980s? We argue that changes in inventory dynamics played a reinforcing—rather than a leading—role in the reduction of output volatility. Since the mid‐1980s, inventory dynamics have changed in a manner consistent with a faster resolution of inventory imbalances. However, these changes appear to be a consequence of changes in the response of industry‐level sales and aggregate economic activity to monetary policy shocks. Our results suggest that it is the interaction between the changes in inventory behavior at the industry level and the macroeconomic environment—where the latter likely includes changes in the conduct of monetary policy and the responses of the economy to policy disturbances—rather than any single factor, that has contributed importantly to the observed decline in economic volatility.
Heterogeneity and Lotteries in Monetary Search Models
Authors: LOTZ SÉBASTIEN , SHEVCHENKO ANDREI , WALLER CHRISTOPHER
Published: May 2007

We introduce ex ante heterogeneity into the Berentsen, Molico, and Wright monetary search model with lotteries. We show that their three main results regarding lotteries do not survive this modification of the environment.
Frequency of Subclinical Heart Disease in Elderly Persons With Dementia
Authors: Reitz Christiane , Brickman Adam M. , Luchsinger José A. , Wu William E. , Small Scott A. , Tang Ming‐Xin , Mayeux Richard
Published: May 2007

The authors compared the frequency of structural and functional heart abnormalities assessed using transthoracic echocardiography among persons with Alzheimer's disease, vascular dementia, stroke, and healthy control subjects. Compared with controls, patients with Alzheimer's disease were more likely to have aortic valve thickening, aortic valve regurgitation, left ventricular wall motion abnormalities, left ventricular hypertrophy, and reduced ejection fraction. Persons with vascular dementia were more likely to have aortic valve regurgitation, but mitral valve thickening and tricuspid valve regurgitation were also more frequent. In the absence of dementia, persons with stroke differed from controls by more frequent mitral valve calcifications. With the increasing prevalence of Alzheimer's disease and vascular dementia, clinicians have to be more attentive to the presence of structural heart disease and its complications in persons with these conditions.
Usefulness of ARBs and ACE Inhibitors in the Prevention of Vascular Dementia in the Elderly
Authors: Hanes Donna S. , Weir Matthew R.
Published: May 2007

Hypertension is a leading risk factor for vascular dementia. With the increasing burden of dementia, prevention and delay of cognitive decline are becoming a priority. Recent clinical trials have demonstrated that patients taking antihypertensive medications have a reduced incidence of dementia and cognitive impairment. Calcium channel blockers, angiotensin‐converting enzyme inhibitors, and angiotensin receptor blockers appear to offer significant neuroprotection, even beyond blood pressure reduction. Evidence is emerging that the angiotensin receptor blockers offer superior neuroprotection. This finding has been attributed to the unique property of sustained blockade of the AT1 receptor, combined with simultaneous activation of the AT2 receptors. The use of angiotensin receptor blockers as first‐line therapy for hypertension and cognitive protection in the elderly should be strongly considered.
The lymphoid cell surface receptor NTB‐A: a novel monoclonal antibody target for leukaemia and lymphoma therapeutics
Authors: Korver Wouter , Singh Shweta , Liu Shouchun , Zhao Xiaoxian , Yonkovich Shirlee , Sweeney Allison , Anton Kristin , Lomas Woodrow E. , Greenwood Rachel , Smith Ashley , Tran Denise Hoang , Shinkawa Pauline , Jimenez Mark , Yeung Patricia , Aguilar Gerard , Palencia Servando , Vatta Paolo , Mueller Matthew , Zhan Xiaoming , Newton Elizabeth M. , Liu Yi , Zhao Jingsong , Emtage Peter , Levy Michael D. , Hsi Eric D. , Funk Walter D. , Abo Arie
Published: May 2007

NTB‐A is a CD2‐related cell surface protein expressed primarily on lymphoid cells including B‐lymphocytes from chronic lymphocytic leukaemia (CLL) and lymphoma patients. We have generated a series of monoclonal antibodies (mAbs) against NTB‐A and assessed their therapeutic potential for CLL. Selective mAbs to NTB‐A were further tested in functional complement‐dependent cytotoxicity (CDC) and antibody‐dependent cellular cytotoxicty (ADCC) assays in cell lines and B lymphocytes freshly isolated from CLL patients. While lower levels of NTB‐A were detected in T and natural killer (NK) cells, CDC activity was demonstrated primarily in B cells isolated from CLL patients and B lymphoma cell lines. Knockdown of NTB‐A by small interfering RNA in target cells results in lower cytotoxicity, demonstrating the specificity of the mAbs. Furthermore, anti NTB‐A mAbs demonstrated anti‐tumour activity against CA46 human lymphoma xenografts in nude mice and against systemically disseminated Raji human lymphoma cells in severe combined immunodeficient mice. Taken together, these results demonstrate NTB‐A as a potential new target for immunotherapy of leukaemia and lymphomas.
Improving the clinical usefulness of a behavioural pain scale for older people with dementia
Authors: Zwakhalen Sandra M.G. , Hamers Jan P.H. , Berger Martijn P.F.
Published: May 2007

Title.  Improving the clinical usefulness of a behavioural pain scale for older people with dementia

Aim.  This paper is a description of the process of item reduction as part of the construction of the Pain Assessment Checklist for Seniors with Limited Ability to Communicate to assess pain in Dutch older nursing home residents with dementia.

Background.  A valid and reliable clinically useful tool is important for assessing pain in people with dementia. The Pain Assessment Checklist for Seniors with Limited Ability to Communicate has demonstrated good inter‐ and intra‐rater reliability and evidence of construct validity. However, nurses found the scale too long for clinical use.

Methods.  In an observational study in 2005, nursing home patients (n = 128) were observed while receiving an influenza injection, and a selection of patients were also assessed at a patient‐specific pain moment. Internal consistency and Principal Component Analysis were used to refine the scale, to examine the psychometric quality and underlying factor structure of the scale.

Results.  A brief and manageable version of the Pain Assessment Checklist for Seniors with Limited Ability to Communicate in Dutch was developed, with a three‐component solution including 24 items. This version had high levels of internal consistency for the complete scale (Cronbach's alpha range 0·82–0·86) and for all subscales (alpha range 0·72–0·82). Social–emotional items played a significant role in detecting pain.

Conclusion.  It is important to have a valid, reliable, brief and manageable pain scale available for the nursing home setting. Further research is needed to examine the adequacy and effectiveness of the scale in daily clinical practice.
General practitioners’ perceptions and attitudes to infertility management in primary care: focus group study
Authors: Wilkes Scott , Hall Nicola , Crosland Ann , Murdoch Alison , Rubin Greg
Published: May 2007

Background  Infertility management in primary care is variable. National Institute of Clinical Excellence have recommended hysterosalpingography (HSG) as a first‐line investigation for tubal assessment.

Aim  To explore general practitioners’ (GPs) perceptions of, and attitudes to, the initial management of the infertile couple and their views on open access to HSG.

Method  Design: Qualitative study using three focus groups. Setting: Seven general practices in Newcastle upon Tyne and Northumberland. Subjects: We purposively selected the three focus groups to provide a range of GPs’ views. In total 13 practitioners participated: 11 GPs, one GP registrar and one nurse practitioner.

Results  The key themes to emerge were: (1) perceived professional responsibilities, (2) uncertainty and lack of knowledge, (3) consistency of approach to the initial management of infertility, and (4) access to infertility services. Some GPs felt that they should do all they possibly could, while others felt it was the responsibility of the infertility specialist. Uncertainty and lack of knowledge was linked to the relative infrequency of primary care infertility consultations and the difficulty ‘keeping up to date’ with rapidly advancing reproductive technologies in tertiary care. Some GPs subscribed to the notion of one suitably trained clinician delivering the service on behalf of a group of GPs. Some were unsure where HSG fitted into the overall management plan, but they were comfortable with following recommended guidelines.

Conclusions  GPs recognize an advocacy role and many take on a significant degree of clinical responsibility welcoming the introduction of a new technology in primary care. Nevertheless, GPs feel that they lack proficiency and have little opportunity to rehearse the necessary skills. These findings contribute to an understanding of the management of infertility, an infrequently presenting problem in primary care.
Distracting communications in the operating theatre
Authors: Sevdalis Nick , Healey Andrew N. , Vincent Charles A.
Published: May 2007

Rationale and aims  Research suggests that there are problems of communication effectiveness in surgery. Here we describe the content, initiators and recipients of communications that intrude or interfere with individual surgical cases. We also consider the level at which the surgical team and its team members are distracted by these case‐irrelevant communications (CICs).

Methods  Two psychologist observers sampled 48 general surgery procedures and they recorded the initiator and the recipient of CIC events, their content and the level of observable distraction that they caused.

Results  Irrelevant comments and queries (i.e. ‘small‐talk’) accounted for half of the observed CICs. From the remaining CICs that we observed, most were related to the organization and administration of the case‐list, to operating theatre provisions and to teaching junior staff. Surgeons initiated a third of the observed CICs, while receiving two thirds of them. External staff visiting the operating theatre initiated the most distracting communications. The CICs addressed to surgeons introduced significantly less distraction to the operating theatre than those addressed to anaesthetists and nurses.

Conclusions  Some of the observed CICs contributed to the administration of the operating theatre case‐list. Nonetheless, this communication can interfere with highly sensitive work. More effectively co‐ordinated communication could reduce this interference. More research should assess the communication effectiveness and the impact of CICs on task performance in the operating theatre.
Comparison of the Bayer VERSANT HCV RNA 3.0 and the Roche COBAS Amplicor HCV Monitor, Version 2.0, assays in HCV genotype 4 infection
Authors: Jessner W. , Watkins‐Riedel T. , Müller C. , Formann E. , Gschwantler M. , Ferenci P.
Published: May 2007

summary Prediction of treatment response is clinically important in chronic hepatitis C virus (HCV) genotype 4 infection. Early viral kinetics is useful in this respect for genotype 1 but interpretation is dependent on assay linearity and reproducibility. The VERSANT HCV RNA 3.0 (bDNA‐3.0) and the COBAS Amplicor HCV Monitor 2.0 (HCM‐2.0) have been widely used quantitative assays. We wanted to comparatively evaluate the two tests in a large genotype 4 sample. Genotyping was performed by NS5b sequencing. Viral load was tested in parallel in 32 patients at least six times on antiviral therapy with interferon α (IFNα). Totally, 198 samples within a quantitative range from undetectable to about 7 × 106 IU/mL (bDNA‐3.0) were obtained and compared. Twenty‐two samples with viral load above 500 000 IU/mL tested by HCM‐2.0 were 1:100 diluted and retested. Quantitative values were fitted to a third order polynomial (M = 0.118303 + 1.07503 × V+ 0.0112128 × V2 − 0.0055504 × V3; M…HCM‐2.0, V…bDNA‐3.0, both log IU/mL) showing progressive nonlinearity of HCM‐2.0 above 100 000 IU/mL but better clinical sensitivity with respect to bDNA‐3.0. Dilution lead to a gain of at least a factor of 2.7 and thus, overestimation compared with bDNA‐3.0. Deviation from linearity and overestimation upon dilution by HCM‐2.0 are similar with HCV genotype 4, compared with other HCV genotypes. Differences in test performance were not detected for subtypes but for individual patients possibly related to specific quasispecies patterns. The interpretation of viral kinetic data becomes difficult due to overestimation upon dilution of baseline values by HCM‐2.0.
Adapting a diet from sugar to meat: double‐dealing genes of Streptococcus pyogenes
Authors: Rosch Jason W. , Tuomanen Elaine
Published: May 2007

Intuitively, paralogues created by gene duplication should retain related functions. However, a study of the two lactose metabolic operons of Streptococcus pyogenes, reported in this issue of Molecular Microbiology, indicates that paralogues might evolve very different functions, in this case changing from a metabolic enzyme to a regulator of virulence. Divergence of paralogues could be a newly recognized theme in the metamorphosis of a bacteria from innocuous to pathogenic.
Identification of mutations that alter the gating of the Escherichia coli mechanosensitive channel protein, MscK
Authors: Li Chan , Edwards Michelle D. , Jeong Hochterl , Roth John , Booth Ian R.
Published: May 2007

Mechanosensitive channels allow bacteria to survive rapid increases in turgor pressure. Substantial questions remain as to how these channels sense and respond to mechanical stress. Here we describe a set of mutants with alterations in their MscK channel protein. The mutants were detected fortuitously by their enhanced ability to modify the accumulation of quinolinic acid. Some amino acid changes lie in the putative pore region of MscK, but others affect sequences that lie amino‐terminal to the domain aligning with MscS. We demonstrate that the alterations in MscK cause the channel to open more frequently in the absence of excessive mechanical stress. This is manifested in changes in sensitivity to external K+ by cells expressing the mutant proteins. Single‐channel analysis highlighted a range of gating behaviours: activation at lower pressures than the wild type, inability to achieve the fully open state or a modified requirement for K+. Thus, the dominant uptake phenotype of these mutants may result from a defect in their ability to regulate the gating of MscK. The locations of the substituted residues suggest that the overall gating mechanism of MscK is comparable to that of MscS, but with subtleties introduced by the additional protein sequences in MscK.
Nuclear factor kappa‐B p50 and p65 subunits expression in dementia with Lewy bodies
Authors: Saldaña M. , Mullol J. , Aguilar E. , Bonastre M. , Marin C.
Published: May 2007

Dementia with Lewy bodies (DLB) is the second most common cause of neurodegenerative dementia after Alzheimer's disease (AD). Parkinsonism in DLB is mainly caused by neuronal loss with Lewy bodies (LBs) in the substantia nigra, thereby inducing degeneration of the nigrostriatal dopaminergic pathway similar to that in Parkinson's disease (PD). To clarify the pathogenesis of DLB, it is important to investigate the mechanisms involved in the degenerative process of LB‐bearing neurones. Several reports suggest a role for nuclear factor kappa‐B (NFκB) in the manifestation of neurodegenerative conditions such as AD and PD. The aim of the present study was to investigate whether NFκB subunits are involved in the pathogenesis of neurodegeneration in DLB by measuring tyrosine hydroxylase (TH), NFκB p65 and p50 protein expression in frontal cortex and substantia nigra pars compacta of DLB and control human brains. An increase, although not statistically significant, in nigral TH expression in DLB cases was observed. There were no differences in the cortical and nigral expression levels of NFκB p65 subunit between control and DLB cases. Western blots of the frontal cortex showed no differences in the expression levels of NFκB p50 subunit. However, NFκB p50 levels were significantly decreased (P < 0.05) in the pars compacta of the substantia nigra in the DLB cases in comparison with controls. The decrease in the expression of the p50 subunit in the substantia nigra of DLB cases achieved in the present study may increase the vulnerability of the dopaminergic neurones to a possible neurotoxic effect of p65 subunit. Thus, normal levels of NFκB p65 might be toxic in neurones with a low expression of the NFκB p50 subunit.
Bone Marrow Dendritic Cells Internalize Live RF‐81 Bovine Rotavirus and Rotavirus‐like Particles (RF 2/6‐GFP‐VLP and RF 8*2/6/7‐VLP) But are Only Activated by Live Bovine Rotavirus
Authors: Istrate C. , Douagi I. , Charpilienne A. , McInerney G. M. , Hidmark Å. , Johansen K. , Larsson M. , Magnusson K.‐E. , Poncet D. , Svensson L. , Hinkula J.
Published: May 2007

Dendritic cells (DC) represent the link between innate and adaptive immunity. They are classified as antigen‐presenting cells (APC) and can initiate and modulate the immune response. To investigate the interaction with DCs, live RF‐81 bovine rotavirus strain (RFV) and rotavirus‐like particles (rota‐VLP), RF 2/6‐GFP‐VLP and rota RF 8*2/6/7‐VLP, were added in vitro to murine bone marrow‐derived DCs (bmDCs). Live RFV, RF 2/6‐GFP‐VLP and RF 8*2/6/7‐VLP all bound to bmDC and were internalized but only live RFV stimulated phenotypic maturation of the bmDCs as shown by the upregulation of the co‐stimulatory molecule CD86. Even though bmDCs internalized RF 2/6‐GFP‐VLP and RF 8*2/6/7‐VLP as efficiently as live RFV, these rota‐VLP were not able to activate the cells. Supernatants derived from bmDC cultures treated with live RFV, RF 2/6‐GFP‐VLP or RF 8*2/6/7‐VLP were examined for TNF‐α production. At 6, 18 and 24 h post‐infection, TNF‐α concentrations were significantly increased in cultures treated with live RFV and rota‐VLP compared with untreated cultures. In conclusion, this study showed that live RF‐81 bovine rotavirus strain was internalized and induced bmDCs activation, whereas both RF 2/6‐GFP‐VLP and RF 8*2/6/7‐VLP were internalized by bmDCs without triggering their activation.
The Double Role of the Endoplasmic Reticulum Chaperone Tapasin in Peptide Optimization of HLA Class I Molecules
Authors: Cabrera C. M.
Published: May 2007

During the assembly of the HLA class I molecules with peptides in the peptide‐loading complex, a series of transient interactions are made with ER‐resident chaperones. These interactions culminate in the trafficking of the HLA class I molecules to the cell surface and presentation of peptides to CD8+ T lymphocytes. Within the peptide‐loading complex, the glycoprotein tapasin exhibits a relevant function. This immunoglobulin (Ig) superfamily member in the endoplasmic reticulum membrane tethers empty HLA class I molecules to the transporter associated with antigen‐processing (TAP) proteins. This review will address the current concepts regarding the double role that tapasin plays in the peptide optimization and surface expression of the HLA class I molecules.
ORIGINAL INVESTIGATIONS ON CPP: Development, extinction and reinstatement of morphine withdrawal‐induced conditioned place aversion in rats
Authors: Li Yi , Liu Xuebing , Chen Hongxian , Deng Huiqiong , Xiang Xiaojun , Chen Hanhui , Hao Wei
Published: May 2007

The motivational component of drug withdrawal may contribute to drug seeking and relapse through the negative reinforcement‐based process. Here, we used conditioned place aversion (CPA) induced by naloxone‐precipitated morphine withdrawal to measure the aversive effects. Using an unbiased conditioning paradigm, we treated rats with morphine hydrochloride [(10 mg/kg intraperitoneally (i.p.)] twice per day (at 08:00 and 20:00) for 6.5 days (from day 1 to day 7 morning), while gave them naloxone (0.3 mg/kg i.p.) on day 6, a precipitated withdrawal paired with a compartment that caused CPA to the side. Then, the rats exhibited CPA were received 12 extinction trials from days 7 to 13, by daily exposed to the two compartments for free exploration. On day 13, the rats with extinguished CPA were treated with a priming injection of morphine (10 mg/kg i.p.) followed by naloxone (0.3 mg/kg i.p.) that reliably reinstated CPA. These results demonstrated that repeatedly morphine‐treated rats showed the formation, extinction and reinstatement of CPA. The present CPA model induced by these procedures may be useful for studying the biological mechanisms underlying the aversive motivational component of opiate withdrawal.
The quality of information about kidney transplantation on the World Wide Web
Authors: Hanif Faisal , Abayasekara Kumar , Willcocks Lisa , Jolly Elaine C , Jamieson Neville V , Praseedom Raaj K , Goodacre John A , Read Janet C , Chaudhry Afzal , Gibbs Paul
Published: May 2007

Abstract:  Background:  Websites on the Internet are used increasingly by patients and those caring for them as a source of medical information. This study investigated the nature and quality of the kidney transplant‐related information currently available on the World Wide Web (WWW).

Methods:  Four common search engines were used to explore the Internet using the keywords “kidney transplantation.” Each website was assessed on the following categories: source, language, accessibility, presence of kitemarks, and quality/depth of information. Websites were scored independently by four transplant clinicians (two surgeons and two physicians), and a weighted Information Score (IS) was created to assess the overall clinical and educational value of the site.

Results:  A total of 200 potential websites were identified of which 94 websites were suitable for scoring. The remaining 106 were repetitions or non‐accessible links. The overall median weighted IS for the sites assessed was 21 (IQR 0–61). Median weighted IS of sites originating from Europe and USA were 47 (IQR = 21–61) and 45 (IQR = 15–61) respectively (p = 0.27). Websites belonging to academic institutions scored higher with a median weighted IS of 49 (IQR = 20–61) when compared with kitemarked websites (median 21, IQR = 5–45, p = 0.01). However, there was no statistically significant difference in weighted IS of kitemarked, professional (median 22, IQR = 2–53), commercial (median 20, IQR = 0–45), and individual websites (median 9, IQR 3–12). There was a good agreement between the observers who scored the websites with an intraclass correlation coefficient (ICC) of 0.79 and an associated 95% CI (0.73–0.90) for the four observers on the 94 websites.

Conclusion:  The educational material currently available on the WWW about kidney transplantation is often of poor quality and more input is required from transplant clinicians. Quality seals in the form of kitemarks may give a false sense of security. The gaps in validity and accuracy of the information available on complex topics such as kidney transplantation should be filled; otherwise poor quality information will continue to be the norm rather than the exception.