bluuebunny/crossref_metadata_2025 huggingface dataset:
The nature of upstream blocking in uniformly stratified flow over long obstacles
Authors: Baines Peter G. , Guest Fiona
Published: April 2006

The general method described in Baines 1988 has been applied to stratified flows of finite depth over long obstacles where the flow initially has uniform horizontal velocity. The fluid consists of a finite number of homogeneous layers of equal thickness and with equal density increments. This represents the state of continuous stratification with constant density gradient as closely as possible, for a given number of layers. Two-, three-, four- and sixty-four-layered models are studied in detail. The results are expressed in terms of the initial Froude number F0 (F0 = U/ĉ1 where U is the fluid speed and ĉ1 is the speed of the fastest long internal wave mode in the fluid at rest) and the obstacle height. In general, introduction of an obstacle into the flow causes disturbances to propagate upstream (columnar disturbance modes) which alter the velocity and density profiles there. These may accumulate to cause upstream blocking of some of the fluid layers if F0 is sufficiently small. As the number of fluid layers increases, so does the range of F0 for which this upstream blocked flow occurs. There are no upstream disturbances for F0 > 1, and for F0 < 1 the upstream disturbances are of the rarefaction type if upstream blocking does not occur. The results for three and four layers show how several coexisting modes may interact to affect the upstream profiles. The results for sixty-four-layers provide theoretical support for the observational criterion (Baines 1979b) that blocking in initially uniformly stratified flow occurs when Nhm/U > 2 (N is the Brunt—Väisälä frequency and hm the obstacle height), provided that more than two modes are present. In some situations, layered models are found to be inadequate as a representation of continuous stratification when one or more layers thicken to the extent that their discreteness is significant.
Thermal convection during the directional solidification of a pure liquid with variable viscosity
Authors: Smith Marc K.
Published: April 2006

The onset of a buoyancy-driven instability during the directional solidification of a pure liquid with a strongly temperature-dependent viscosity and an arbitrary Prandtl number is investigated using linear stability theory. The Rayleigh number for this system contains the lengthscale Ls defined as the ratio of the thermal diffusivity of the liquid and the solidification velocity times the density ratio of the two phases. It is independent of the actual depth of the liquid and it reflects the fact that increasing the solidification velocity stabilizes the system. The theory also shows that the difference in material properties between the two phases and the properties of the solidifying interface itself cause the interface to look like a boundary of finite conductivity measured by a wavenumber-dependent Biot number. For large viscosity variations, convection occurs below a stagnant layer which forms just beneath the interface where the liquid is immobilized by its very large viscosity. The thickness of this layer is measured by the natural logarithm of the viscosity contrast in the liquid times the lengthscale Ls. In this limit, the influence of the solidifying boundary is shielded from the bulk liquid by the stagnant layer and so the effect of the Biot number on the critical Rayleigh number is small. However, inertial effects, being associated with the bulk liquid, are very important for small Prandtl numbers of the fluid far from the interface. The model has applications to the solidification of magma chambers or lava lakes and to the material processing of polymeric liquids.
A note on the divergence effect and the Lagrangian-mean surface elevation in periodic water waves
Authors: Mcintyre M. E.
Published: April 2006

Longuet-Higgins’ exact expression for the increase in the Lagrangian-mean elevation of the free surface due to the presence of periodic, irrotational surface gravity waves is rederived from generalized Lagrangian-mean theory. The raising of the Lagrangian-mean surface as wave amplitude builds up illustrates the non-zero divergence of the Lagrangian-mean velocity field in an incompressible fluid.
Instability of swirl in low-Prandtl-number thermal convection
Authors: Massaguer Josep M. , Mercader Isabel
Published: April 2006

In the present paper we examine low-Prandtl-number thermal convection using a highly truncated modal approach. For the horizontal structure we assume a hexagonal planform as in Toomre Gough & Spiegel (1977) but including a vertical vorticity mode. The system develops a non-zero vertical vorticity component through a finite-amplitude instability. Following this, the system displays a Hopf bifurcation giving rise to periodic oscillations. The mechanism for this instability is associated with the growth of swirl in the azimuthal direction. We have found three different types of periodic solutions, possibly associated with subharmonic bifurcations, and their structure has been examined.

A large part of the present work is devoted to exploring the cases of mercury and liquid helium - or air - as the best-known examples of low and intermediate-Prandtl-number fluids. Results for mercury are quite satisfactory as far as frequencies and fluxes are concerned and they show reasonable agreement with experimental measurements at mildly supercritical Rayleigh values. On the other hand, for liquid helium or air agreement is poor.
The stability of stationary waves in a wavy-walled channel
Authors: Mchugh John Philip
Published: April 2006

Experiments by Binnie showed that unsteady waves were produced by flow through a channel with symmetric, wavy sidewalls, with waves propagating both upstream and downstream. However, the first-order solution to this problem that was obtained by Yih is a set of steady waves. The steady solution is shown to be unstable to a pair of infinitesimal disturbance waves which satisfy the resonance conditions of Phillips. For the Froude-number range used by Binnie, a pair of disturbances has been found such that one wave propagates upstream, one propagates downstream, and the amplitudes have an exponential growth. The Froude numbers outside the range of Binnie are also shown to be unstable. The steady waves produced by flow through an antisymmetric channel are shown to be unstable in the same manner.
Interpretation of shadowgraph patterns in Rayleigh-Bénard convection
Authors: Jenkins D. R.
Published: April 2006

The relationship between observations of cellular Rayleigh-Bénard convection using shadowgraphs and theoretical expressions for convection planforms is considered. We determine the shadowgraphs that ought to be observed if the convection is as given by theoretical expressions for roll, square or hexagonal planforms and compare them with actual experiments. Expressions for the planforms derived from linear theory, valid for low supercritical Rayleigh number, produce unambiguous shadowgraphs consisting of cells bounded by bright lines, which correspond to surfaces through which no fluid flows and on which the vertical component of velocity is directed downwards. Dark spots at the centre of cells, indicating regions of hot, rising fluid, are not accounted for by linear theory, but can be produced by adding higher-order terms, predominantly due to the temperature dependence of a material property of the fluid, such as its viscosity.
Report on the IUTAM symposium: fundamental aspects of vortex motion
Authors: Aref H. , Kambe T.
Published: April 2006

The IUTAM Symposium Fundamental Aspects of Vortex Motion was held in Tokyo, Japan, from 31 August to 4 September 1987. We present an account of the technical sessions of that meeting. The main goals of this report are (i) to provide a widely accessible record of the four-and-one-half day meeting; (ii) to identify important new developments in the field of vortex dynamics of potential interest to a larger audience than the invited attendees; and (iii) to attempt some overview comments with the wisdom of hindsight that may be useful as a guide to specific papers in the proceedings and other current literature.
Existence and some properties of waves trapped by submerged cylinders
Authors: Aranha J. A. P.
Published: April 2006

In this paper the mathematical formulation associated with waves trapped by submerged cylinders is recast as a standard eigenvalue problem. In this way the existence is proven of trapped waves for every frequency Ω, and for arbitrary geometry of the submerged cylinder. At the same time a simple expression for the first eigenvalue and eigenmode, correct in the limits Ω → 0 or Ω → ∞, is derived. The expression can be a useful approximation for a structure relatively transparent to the wave action such as, for instance, a semisubmersible platform.
The stability of boundary-layer flow over single-and multi-layer viscoelastic walls
Authors: Yeo K. S.
Published: April 2006

In this paper, we are concerned with the linear stability of zero pressure-gradient laminar boundary-layer flow over compliant walls which are composed of one or more layers of isotropic viscoelastic materials and backed by a rigid base. Wall compliance supports a whole host of new instabilities in addition to the Tollmien-Schlichting mode of instability, which originally exists even when the wall is rigid. The perturbations in the flow and the compliant wall are coupled at their common interface through the kinematic condition of velocity continuity and the dynamical condition of stress continuity. The disturbance modes in the flow are governed by the Orr-Sommerfeld equation using the locally-parallel flow assumption, and the response of the compliant layers is described using a displacement-stress formalism. The theoretical treatment provides a unified formulation of the stability eigenvalue problem that is applicable to compliant walls having any finite number of uniform layers; inclusive of viscous sublayer. The formulation is well suited to systematic numerical implementation. Results for single- and multi-layer walls are presented. Analyses of the eigenfunctions give an insight into some of the physics involved. Multi-layering gives a measure of control over the stability characteristics of compliant walls not available to single-layer walls. The present study provides evidence which suggests that substantial suppression of disturbance growth may be possible for suitably tailored compliant walls.
Viscoelastic response of a floating ice plate to a steadily moving load
Authors: Hosking R. J. , Sneyd A. D. , Waugh D. W.
Published: April 2006

Viscoelastic theory is used to describe the response of a floating ice sheet to a moving vehicle. We adopt a two-parameter memory function to describe the behaviour of the ice, subjected to a steadily moving line or point load. The viscoelastic dissipation produces an asymmetric quasi-static response at subcritical speed, renders a finite response at the critical speed, and damps the shorter leading waves rather more severely than the longer trailing waves at supercritical speed. We extend earlier asymptotic theory to consider the anisotropic damping of the flexural waves. There is enhanced agreement between theory and experiment.
Viscoelastic inertial flow driven by an axisymmetric accelerated surface
Authors: Larson R. G.
Published: April 2006

A similarity transform is used to analyse the flow of an upper-convected Maxwell fluid in an infinitely long cylinder whose surface has a velocity that increases in magnitude linearly with axial coordinate. Two types of problem are considered, the accelerated surface flow - when the surface velocity is outward towards the tube ends, and the decelerated surface flow - when it is inward. For the accelerated surface flow, the introduction of elasticity prevents the loss of similarity solution that occurs without elasticity at a Reynolds number (Re) of 10.25: with elasticity, solutions up to a Reynolds number of 95 were computed. As elasticity is introduced, normal stress gradients in an elastic boundary layer near the accelerated surface help offset inertially generated negative axial pressure gradients; with sufficient elasticity the turning point in the non-elastic solution family at Re = 10.25 disappears. For the decelerated surface flow, solutions could not be computed beyond a critical Re that depends on the level of elasticity considered, because at this critical Re, the axial velocity profile at the centreline becomes infinitely blunt.
Squawk talk: commentary by birds in the Bayeux Tapestry?
Authors: Owen-Crocker Gale R.
Published: April 2006

A brief history of the tradition of birds as motifs on textiles is followed by a catalogue of the birds in the Bayeux Tapestry and a discussion of their function. The possible significance of identifiable birds (cocks, doves, peacocks, storks), the birds of Aesop's fables and the creatures in the border ‘bird scaring scene’ is analysed. The individuality, in colouring and position, of all the border birds is demonstrated and the apparent interest which many of them take in the action of the main register is highlighted to suggest that the border birds present a commentary on, and audience-participation in, the narrative.
X-ray study of the electric double layer at the n-hexane/nanocolloidal silica interface
Authors: Tikhonov Aleksey M.
Published: April 2006

The spatial structure of the transition region between an insulator and an electrolyte solution was studied with x-ray scattering. The electron-density profile across the n-hexane/silica sol interface (solutions with 5, 7, and 12nm colloidal particles) agrees with the theory of the electrical double layer and shows separation of positive and negative charges. The interface consists of three layers, i.e., a compact layer of Na+, a loose monolayer of nanocolloidal particles as part of a thick diffuse layer, and a low-density layer sandwiched between them. Its structure is described by a model in which the potential gradient at the interface reflects the difference in the potentials of “image forces” between the cationic Na+ and anionic nanoparticles and the specific adsorption of surface charge. The density of water in the large electric field (∼109–1010V∕m) of the transition region and the layering of silica in the diffuse layer is discussed.
High-reflectivity ultraviolet AlGaN∕AlGaN distributed Bragg reflectors
Authors: Mitrofanov O. , Schmult S. , Manfra M. J. , Siegrist T. , Weimann N. G. , Sergent A. M. , Molnar R. J.
Published: April 2006

We demonstrate high-reflectivity crack-free Al0.18Ga0.82N∕Al0.8Ga0.2N distributed Bragg reflectors (DBR) for the spectral region around 350nm grown by molecular-beam epitaxy on thick GaN templates. The structural quality of the DBR layers is maintained by compensating the compressive and tensile stress in each λ∕4 pair. This approach results in the lowest elastic strain energy and allows the growth of thick coherently strained DBRs. A 25 period mirror provides a 26nm wide stop band centered at 347nm with the maximum reflectivity higher than 99%.
Electroluminescence from ZnO nanowire/polymer composite p-n junction
Authors: Chang Chih-Yang , Tsao Fu-Chun , Pan Ching-Jen , Chi Gou-Chung , Wang Hung-Ta , Chen Jau-Juin , Ren F. , Norton D. P. , Pearton S. J. , Chen Kuei-Hsien , Chen Li-Chyong
Published: April 2006

The characteristics of a hybrid p-n junction consisting of the hole-conducting polymer poly(3,4-ethylene-dioxythiophene)-poly(styrene-sulfonate) (PEDOT/PSS) and n-ZnO nanorods grown on an n-GaN layer on sapphire are reported. Spin coating of polystyrene was used to electrically isolate neighboring nanorods and a top layer of transparent conducting indium tin oxide (ITO) was used to contact the PEDOT/PSS. Multiple peaks are observed in the electroluminescence spectrum from the structure under forward bias, including ZnO band edge emission at ∼383nm as well as peaks at 430, 640, and 748nm. The threshold bias for UV light emission was <3V, corresponding to a current density of 6.08Acm−2 through the PEDOT/PSS at 3V.
Negative differential resistance in dislocation-free GaN∕AlGaN double-barrier diodes grown on bulk GaN
Authors: Golka S. , Pflügl C. , Schrenk W. , Strasser G. , Skierbiszewski C. , Siekacz M. , Grzegory I. , Porowski S.
Published: April 2006

Double-barrier GaN resonant tunneling diodes with AlGaN barriers were fabricated on bulk (0001) single-crystal GaN substrates. Layers were grown using molecular-beam epitaxy with a rf plasma nitrogen source. Single diodes of 6μm diameter were prepared by inductively coupled plasma reactive ion etching. For many diodes clear negative differential resistance is observed around 2V with peak currents around 10kA∕cm2 and a peak-to-valley ratio of about 2 at room temperature. Its observation does not depend on specific conditions of measurement; however, it slowly decays after each measurement. The mechanism behind this decay is investigated since it is obviously prohibiting the usage of GaN resonant tunneling diodes so far. It is shown not to be caused by catastrophic breakdown of the devices.
ZnO light-emitting diode grown by plasma-assisted metal organic chemical vapor deposition
Authors: Xu W. Z. , Ye Z. Z. , Zeng Y. J. , Zhu L. P. , Zhao B. H. , Jiang L. , Lu J. G. , He H. P. , Zhang S. B.
Published: April 2006

We report a breakthrough in fabricating ZnO homojunction light-emitting diode by metal organic chemical vapor deposition. Using NO plasma, we are able to grow p-type ZnO thin films on n-type bulk ZnO substrates. The as-grown films on glass substrates show hole concentration of 1016–1017cm−3 and mobility of 1–10cm2V−1s−1. Room-temperature photoluminescence spectra reveal nitrogen-related emissions. A typical ZnO homojunction shows rectifying behavior with a turn-on voltage of about 2.3V. Electroluminescence at room temperature has been demonstrated with band-to-band emission at I=40mA and defect-related emissions in the blue-yellow spectrum range.
Recruiting Teen Smokers in Shopping Malls to a Smoking‐Cessation Program Using the Foot‐in‐the‐Door Technique
Authors: Bloom Paul N. , McBride Colleen M. , Pollak Kathryn I. , Schwartz‐Bloom Rochelle D. , Lipkus Isaac M.
Published: April 2006

Persuading teen smokers to volunteer for smoking‐cessation programs is a challenging yet understudied problem. As a method of dealing with this problem, we used and tested a foot‐in‐the‐door (FITD) approach. Teen smokers were intercepted at malls and were assigned randomly to request compliance with a small behavior request of either (a) answering a few questions (light FITD) or (b) answering the same questions and a few additional ones, plus watching a short video about the effects of nicotine (heavy FITD). Participants were then called back by telephone several weeks later and asked to comply with a large behavior request of joining a cessation program that involved the use of self‐help materials and telephone counseling. Although no differences were found in responses from the light and heavy groups, consent to enter the program was obtained from 12% of the pooled qualified intercepts and their parents (for those under 18 years). This recruitment rate was considered good, given that this is one of the only reported studies that recruited teen smokers from the general population to cessation programs.
High sensitivity detection of epidermal growth factor receptor mutations in the pleural effusion of non‐small cell lung cancer patients
Authors: Kimura Hideharu , Fujiwara Yutaka , Sone Takashi , Kunitoh Hideo , Tamura Tomohide , Kasahara Kazuo , Nishio Kazuto
Published: April 2006

Epidermal growth factor receptor (EGFR) mutations are a strong determinant of tumor response to gefitinib in non‐small cell lung cancer (NSCLC). We attempted to elucidate the feasibility of EGFR mutation detection in cells of pleural effusion fluid. We obtained 24 samples of pleural effusion fluid from NSCLC patients. The pleural effusion fluid was centrifuged, and the cellular components obtained were used for detection. EGFR mutation status was determined by a direct sequencing method (exons 18–21) and by the Scorpion Amplified Refractory Mutation System (ARMS) method. EGFR mutations were detected in eight cases. Three mutations were detected by both methods, and the other five mutations were detected by Scorpion ARMS alone. The mutations were detected by both methods in all four partial responders among the seven patients who received gefitinib therapy. Direct sequencing detected the mutations in only two of four cases with partial response. These results suggest that the DNA in pleural effusion fluid can be used to detect EGFR mutations. The Scorpion ARMS method appears to be more sensitive for detecting EGFR mutations than the direct sequencing method. (Cancer Sci 2006; 97: 642–648)
Radiation carcinogenesis in mouse thymic lymphomas
Authors: Kominami Ryo , Niwa Ohtsura
Published: April 2006

Ionizing radiation is a well‐known carcinogen for various human tissues and a complete carcinogen that is able to initiate and promote neoplastic progression. Studies of radiation‐induced mouse thymic lymphomas, one of the classic models in radiation carcinogenesis, demonstrated that even the unirradiated thymus is capable of developing into full malignancy when transplanted into the kidney capsule or subcutaneous tissue of irradiated mice. This suggests that radiation targets tissues other than thymocytes to allow expansion of cells with tumorigenic potential in the thymus. The idea is regarded as the ‘indirect mechanism’ for tumor development. This paper reviews the indirect mechanism and genes affecting the development of thymic lymphomas that we have analyzed. One is the Bcl11b/Rit1 tumor suppressor gene and the other is Mtf‐1 gene affecting tumor susceptibility. (Cancer Sci 2006; 97: 575–581)
Vitamin A supplementation increases ratios of proinflammatory to anti-inflammatory cytokine responses in pregnancy and lactation
Authors: Cox S E , Arthur P , Kirkwood B R , Yeboah-Antwi K , Riley E M
Published: April 2006

Vitamin A supplementation reduces child mortality in populations at risk of vitamin A deficiency and may also reduce maternal mortality. One possible explanation for this is that vitamin A deficiency is associated with altered immune function and cytokine dysregulation. Vitamin A deficiency in pregnancy may thus compound the pregnancy-associated bias of cellular immune responses towards Th-2-like responses and exacerbate susceptibility to intracellular pathogens. We assessed mitogen and antigen-induced cytokine responses during pregnancy and lactation in Ghanaian primigravidae receiving either vitamin A supplementation or placebo. This was a double-blind, randomized, placebo-controlled trial of weekly vitamin A supplementation in pregnant and lactating women. Pregnancy compared to postpartum was associated with a suppression of cytokine responses, in particular of the proinflammatory cytokines interferon (IFN)-γ and tumour necrosis factor (TNF)-α. Mitogen-induced TNF-α responses were associated with a decreased risk of peripheral parasitaemia during pregnancy. Furthermore, vitamin A supplementation was significantly associated with an increased ratio of mitogen-induced proinflammatory cytokine (IFN-γ) to anti-inflammatory cytokine (IL-10) during pregnancy and in the postpartum period. The results of this study indicate that suppression of proinflammatory type 1 immune responses and hence immunity to intracellular infections, resulting from the combined effects of pregnancy and vitamin A deficiency, might be ameliorated by vitamin A supplementation.
Class‐3c compression bandaging for venous ulcers: comparison of spiral and figure‐of‐eight techniques
Authors: Coull Alison , Tolson Debbie , McIntosh Jean
Published: April 2006

Aim.  This paper reports a study to compare the differences in compression produced on a limb using a spiral and a figure‐of‐eight bandaging technique.

Background.  Chronic leg ulcers are a major health problem in Western countries. Compression bandaging is the accepted treatment for venous leg ulcers. The spiral and the figure‐of‐eight techniques are traditional methods of applying compression bandages. but their performance in terms of pressure profiles is unknown. Despite a lack of evidence about technique, class‐3c compression bandages are not currently recommended for application in a figure‐of‐eight as this is thought to produce dangerously high pressure.

Methods.  A cross‐over experimental design was used with a sample of 26 nurse bandagers. Consistency of performance was tested. Bandage stretch and overlap were measured and analysed by standard deviation to ensure that the techniques were consistent and repeatable. Pressure probes were then applied to the medial, posterior and lateral aspects of the lower limb of a healthy volunteer. The class‐3c compression bandage was applied using both techniques and the pressure profiles around the leg were measured under the bandage. The results of each technique were compared using independent sample t‐tests. The data were collected in 1999.

Results.  The figure‐of‐eight technique provided statistically significantly higher compression at lower areas of the leg than the spiral technique. Mean pressure difference was 20·3 mmHg at the ankle, 22·2 mmHg at the gaiter, 9·4 mmHg at the calf. The pressure differences decrease towards the knee with both techniques and decrease more steeply with the figure‐of‐eight technique.

Conclusion.  The spiral technique was a safe and comfortable method of bandage application. The figure‐of‐eight also provided graduated compression but with some high areas of pressure, notably overlying the Achilles tendon. However, before firm practice recommendations are made, replication of the study using a padding layer and a larger sample is needed.
MreB of Streptomyces coelicolor is not essential for vegetative growth but is required for the integrity of aerial hyphae and spores
Authors: Mazza Paola , Noens Elke E. , Schirner Kathrin , Grantcharova Nina , Mommaas A. Mieke , Koerten Henk K. , Muth Günther , Flärdh Klas , Van Wezel Gilles P. , Wohlleben Wolfgang
Published: April 2006

MreB forms a cytoskeleton in many rod‐shaped bacteria which is involved in cell shape determination and chromosome segregation. PCR‐based and Southern analysis of various actinomycetes, supported by analysis of genome sequences, revealed mreB homologues only in genera that form an aerial mycelium and sporulate. We analysed MreB in one such organism, Streptomyces coelicolor. Ectopic overexpression of mreB impaired growth, and caused swellings and lysis of hyphae. A null mutant with apparently normal vegetative growth was generated. However, aerial hyphae of this mutant were swelling and lysing; spores doubled their volume and lost their characteristic resistance to stress conditions. Loss of cell wall consistency was observed in MreB‐depleted spores by transmission electron microscopy. An MreB–EGFP fusion was constructed to localize MreB in the mycelium. No clearly localized signal was seen in vegetative mycelium. However, strong fluorescence was observed at the septa of sporulating aerial hyphae, then as bipolar foci in young spores, and finally in a ring‐ or shell‐like pattern inside the spores. Immunogold electron microscopy using MreB‐specific antibodies revealed that MreB is located immediately underneath the internal spore wall. Thus, MreB is not essential for vegetative growth of S. coelicolor, but exerts its function in the formation of environmentally stable spores, and appears to primarily influence the assembly of the spore cell wall.
Fine‐scale time‐lapse analysis of the biphasic, dynamic behaviour of the two Vibrio cholerae chromosomes
Authors: Fiebig Aretha , Keren Kinneret , Theriot Julie A.
Published: April 2006

Using fluorescent repressor‐operator systems in live cells, we investigated the dynamic behaviour of chromosomal origins in Vibrio cholerae, whose genome is divided between two chromosomes. We have developed a method of analysing fine‐scale motion in the curved co‐ordinate system of vibrioid bacteria. Using this method, we characterized two different modes of chromosome behaviour corresponding to periods between segregation events and periods of segregation. Between segregation events, the origin positions are not fixed but rather maintained within ellipsoidal caged domains, similar to eukaryotic interphase chromosome territories. These domains are approximately 0.4 µm wide and 0.6 µm long, reflecting greater restriction in the short axis of the cell. During segregation, movement is directionally biased, speed is comparable between origins, and cell growth can account for nearly 20% of the motion observed. Furthermore, the home domain of each origin is positioned by a different mechanism. Specifically, the oriCI domain is maintained at a constant actual distance from the pole regardless of cell length, while the oriCII domain is maintained at a constant relative position. Thus the actual position of oriCII varies with cell length. While the gross behaviours of the two origins are distinct, their fine‐scale dynamics are remarkably similar, indicating that both experience similar microenvironments.
Amplification of the epidermal growth factor receptor in astrocytic tumours by chromogenic in situ hybridization: association with clinicopathological features and patient survival
Authors: Järvellä S. , Helin H. , Haapasalo J. , Järvellä T. , Junttila T. T. , Elenius K. , Tanner M. , Haapasalo H. , Isola J.
Published: April 2006

Chromogenic in situ hybridization (CISH) was used to detect amplification of the epidermal growth factor receptor (EGFR) gene in tissue microarrays of tumours derived from 287 patients with grade II–IV diffuse astrocytomas. Amplification was found in 32% of the tumours with a highly significant association with histological grade (4% in grade II, 21% in grade III and 39% in grade IV; P < 0.001). Amplification of the EGFR gene was more common in primary than in secondary glioblastomas (41%vs. 16%, P = 0.033). Overexpression of EGFR mRNA and protein (wild‐type and vIII variant) was found to correlate with EGFR gene amplification (P = 0.028, P = 0.035 and P = 0.014 respectively), but wild‐type EGFR protein was also frequently overexpressed in tumours without EGFR gene amplification. Patients with older age (P < 0.001) and tumours with lack of p53 overexpression (P = 0.03) and higher apoptosis rate (P < 0.001) had significantly more EGFR gene amplifications than their counterparts. No such correlation with apoptosis was found in glioblastomas. The survival of patients with EGFR gene‐amplified grade III tumours was significantly shorter than in those with grade III non‐amplified tumours (P = 0.03). No such difference was noted in glioblastomas (grade IV tumours). Our data verify the central role of EGFR in the pathobiology of astrocytic tumours, and highlight the advantages of CISH as a simple and practical assay to screen for EGFR gene amplification in astrocytic tumours.
Growth inhibitory effects of interferon‐α subtypes vary according to human liver cancer cell lines
Authors: Yano Hirohisa , Yanai Yoshiaki , Momosaki Seiya , Ogasawara Sachiko , Akiba Jun , Kojiro Sakiko , Moriya Fukuko , Fukahori Suguru , Kurimoto Masashi , Kojiro Masamichi
Published: April 2006

Background:  Interferon (IFN)‐α preparations used in the treatment of viral and neoplastic disease consist of single or multiple IFN‐α subtypes that may possess different biological activity, but there are no data on liver cancer cells.

Methods:  Antiproliferative effects and the mechanisms of growth inhibition of five IFN‐α subtypes (α1, α2, α5, α8 and α10) were examined in vitro using 13 human liver cancer cell lines.

Results:  The antiproliferative effect of each IFN‐α subtype was different in each cell line. The 50% growth inhibitory concentration (IC50) on an antiviral unit basis showed that α5 presented the most potent antiproliferative effects in 11 of the 13 cell lines, and α8 in two cell lines. On average, the antiproliferative effects were strong in descending order from α5, α8, α10, α2 to α1. On weight basis, the most potent antiproliferative effect was shown by α8 in nine of the 13 cell lines, α5 in four cell lines, and the potency of the effects on average in descending order was α8, α5, α10, α2 and α1. No significant difference was observed between natural and recombinant α2. The mechanism of growth inhibition of each subtype in HAK‐1B and KMCH‐1 cell lines were apoptosis and S‐phase arrest, and their induction levels were related to a certain degree to the antiproliferative effects.

Conclusions:  Our findings show that the antiproliferative effect of each IFN‐α subtype varies according to the cell line, but that the cells are relatively or absolutely responsive to α5 and α8 subtypes.
Predictors for squamous re‐epithelialization of Barrett’s esophagus after endoscopic biopsy
Authors: Amano Yuji , Kushiyama Yoshinori , Yuki Takafumi , Takahashi Yoshiko , Chinuki Daisuke , Ishimura Norihisa , Furuta Kenji , Ishihara Shunji , Adachi Kyoichi , Maruyama Riruke , Kinoshita Yoshikazu
Published: April 2006

Background and Aim:  Acid suppressive therapy has been reported to regress Barrett’s esophagus. However, it is still controversial as to whether all Barrett’s esophagus patients respond to this therapy. The factors that might facilitate newly developed squamous re‐epithelialization after biopsy excision of Barrett’s mucosa were evaluated to identity individuals who may favorably respond to the regression therapy.

Methods:  Two hundred and forty‐seven biopsy sites from 185 patients with Barrett’s esophagus were examined by endoscopy to investigate possible squamous re‐epithelialization of Barrett’s mucosa after endoscopic biopsy. Before endoscopic examination, all participants were requested to answer questionnaires concerning sociodemographic characteristics, lifestyle habits and drugs usage. The mucin phenotype, Cdx2 expression, cyclooxygenase‐2 expression, cellular proliferation and apoptosis of Barrett’s mucosa were immunohistochemically investigated in the biopsy samples taken from Barrett’s esophagus. The influence of these factors on the newly developed squamous re‐epithelialization of Barrett’s mucosa after endoscopic biopsy excision was evaluated.

Results:  By multivariate analysis, the independent factors that favored squamous re‐epithelialization were the gastric mucin predominant phenotype of Barrett’s mucosa and the absence of Cdx2 protein expression. In Barrett’s mucosa with the gastric predominant mucin phenotype, proton pump inhibitor administration, the absence of reflux esophagitis and a low proliferating cell nuclear antigen index were found to be independent predictors for squamous re‐epithelialization.

Conclusions:  The absence of the intestinal predominant mucin phenotype was a positive predictor for newly developed squamous re‐epithelialization at the site of biopsy of Barrett’s mucosa. Only Barrett’s esophagus with the gastric predominant mucin phenotype may predict a favorable response to acid suppressive therapy.
417–2α‐Tocopherol and ascorbic acid attenuates the ribavirin‐induced decrease of eicosapentaenoic acid in erythrocyte membrane in chronic hepatitis C patients
Authors: Hino Keisuke , Murakami Yasuko , Nagai Ayako , Kitase Akira , Hara Yuichi , Furutani Takakazu , Ren Fenyu , Yamaguchi Yuhki , Yutoku Kohki , Yamashita Satoyoshi , Okuda Michiari , Okita Misako , Okita Kiwamu
Published: April 2006

Background:  Oxidative damage of the erythrocyte membrane plays an important role in ribavirin‐induced anemia. The purpose of the present paper was to assess whether supplementation of α‐tocopherol and ascorbic acid (vitamins) causes changes in the erythrocyte membrane fatty acid composition during interferon and ribavirin combination therapy for chronic hepatitis C patients.

Methods:  Fatty acid compositions in erythrocyte membrane phospholipids were determined by gas chromatography at 0, 2, 4, 8 weeks, and at the end of combination therapy (26 weeks) for interferon with ribavirin in 32 patients with chronic hepatitis C who were randomized to receive vitamins or not (controls).

Results:  Good compliance with orally administered vitamins and ribavirin were confirmed by their concentrations in erythrocytes or plasma. The hemoglobin level was negatively correlated with the ribavirin concentration at 8 weeks (r = 0.59, P = 0.01) after initiation of therapy in controls, but not in the vitamin group. Among the 26 kinds of fatty acids analyzed, only eicosapentaenoic acid (EPA) significantly decreased at 8 weeks after initiation of therapy (P = 0.03) and at the end of therapy (P = 0.004) in controls. Vitamins did not inhibit ribavirin‐induced anemia, but attenuated the decrease of EPA in erythrocytes. The EPA level was negatively correlated with the drop in hemoglobin levels at 8 weeks after initiation of therapy in controls (r = 0.58, P = 0.015), but not in the vitamin group.

Conclusions:  Supplementation of α‐tocopherol and ascorbic acid attenuates the ribavirin‐induced decrease of EPA in erythrocyte membrane phospholipids in chronic hepatitis C patients.
Aid Effectiveness on Accumulation: A Meta Study
Authors: Doucouliagos Hristos , Paldam Martin
Published: April 2006

The AEL (aid effectiveness literature) studies the macroeconomic effects of development aid using cross‐country or panel data econometrics. It contains 97 papers of which 43 study whether development aid leads to increasing accumulation. The aggregate results of the 43 studies are that aid increases investment with about 25% of the aid, while most of the remaining 75% of the effect is crowded out by a fall in savings. However, these aggregate results are so variable that it is dubious if accumulation rises.
Were People in the Past Poor and Miserable?
Authors: Kenny Charles
Published: April 2006

Standard economic theory would suggest close linkages between income, broader measures of the quality of life and ‘utility’. To some extent it is hard to test the link between income and utility given the way that utility is proxied by economists, but we do have measures of objective and subjective wellbeing as a potential guide. When we look at broader measures of objective and subjective wellbeing in both rich and poor countries today, the relationship to absolute income is perhaps surprisingly weak. Turning to the past, we know that most people were in an absolute income sense very poor, and faced a considerably lower broad quality of life using objective measures. However, the link between these two factors is not as straightforward as sometimes assumed. At the same time, from the preoccupations of political thinkers and others, it does appear that relative (rather than absolute) income has long been a concern, and that concerns with absolute income at the national level appear to center around avoiding absolute deprivation rather than the advantage of ever more consumption goods. In short, there is plentiful evidence that people in the past were nearly all absolutely poor and broadly worse off according to other objective quality of life measures, less evidence that these two were intimately linked, even less that everyone was miserable, and less again that those who did feel miserable felt so because they were absolutely poor.
Key Aspects of Psychological Change in Residents of a Prison Therapeutic Community: A Focus Group Approach
Authors: MILLER SARAH , SEES CARLY , BROWN JENNIFER
Published: April 2006

Abstract: In an attempt to gain a person‐centred perspective of therapeutic change, exploratory focus groups were conducted with men in Dovegate Prison's Therapeutic Community (TC). Residents identified change as a process comprising variability, gradual movement and differential paces. The process was seen to involve self‐referential properties, interpersonal facets and challenges. Residents distinguished two significant change events: identifying aspects of the unknown and openness to receive help. Support is given to focus group methodology as a way of offering novel insights into experience of a TC as a process‐orientated model of change, taking into account individual aspects and underlying facets of change.
‘Are you allowed to say that?’ using video materials to provide accessible information about psychology services
Authors: Dunn Andy , Kroese Biza Stenfert , Kroese Biza Stenfert , Thomas Gail , McGarry Alison , Drew Pip
Published: April 2006

The White Paper ‘Valuing People’ [Department of Health (DoH) (2001)Valuing people: a new strategy for learning disability for the 21st century, London, HMSO] indicates that people with a learning disability need to become more actively involved in the decisions that affect their lives. This includes being offered active choices in access to health services. Psychologists, therefore, need to think about how to give people with learning disabilities enough relevant information in an accessible way to promote informed consent to treatment. This study investigates how much information adults with mild and moderate learning disabilities understand about psychology services, before and after watching a video designed to explain what seeing a psychologist entails. The video was shown to 19 participants at a local Social Education Centre. Participants’ knowledge increased significantly after watching the video. They were able to answer questions about its content better when asked after short sections of the video when presented, rather than after an uninterrupted presentation.
Kinship and social structure of bobcats (Lynx rufus) inferred from microsatellite and radio‐telemetry data
Authors: Janečka J. E. , Blankenship T. L. , Hirth D. H. , Tewes M. E. , Kilpatrick C. W. , Grassman L. I.
Published: April 2006

Kinship analysis using 12 microsatellites was compared with radio‐telemetry data to examine the social structure of bobcatsLynx rufusin southern Texas. Genetically identified kinship relationships combined with capture data were used to reconstruct pedigrees. Three family groups were constructed from parent/offspring pairs identified from shared alleles. All parents identified by genetic analysis had established home ranges. Individuals with no distinct home ranges were not genetically observed to have offspring among the bobcats sampled. This suggests that establishing a home range is necessary for bobcats to breed. Of three identified male offspring and three identified female offspring, two female offspring were philopatric. These females became a part of the breeding population in their natal area. Among sibling pairs that included nine female and four male individuals, four females and one male were residents suggesting male‐biased dispersal.
The role of LPA1 in formation of synapses among cultured hippocampal neurons
Authors: Pilpel Yair , Segal Menahem
Published: April 2006

We studied the lysophosphatidic acid receptor‐1 (LPA1) gene, which we found to be expressed endogenously in cultured hippocampal neurons, and in vivo in young (1‐week‐old) rat brain slices. Overexpressed green fluorescent protein (GFP)‐tagged, membrane‐associated LPA1 accumulated in a punctate manner over the entire dendritic tree and caused an increase in dendritic spine density. About half of the dendritic spines in the LPA1‐transfected neurons displayed distinct fluorescent puncta, and this subset of spines was also substantially larger than puncta‐free, LPA1‐transfected or control GFP spines. This phenotype could also be seen in cells transfected with a ligand‐binding, defective mutant and is therefore not dependent on interaction with an ambient ligand. While spontaneous miniature excitatory synaptic currents were of the same amplitudes, they decayed slower in LPA1‐transfected neurons compared with GFP controls. We propose that LPA1 may play a role in the formation and modulation of the dendritic spine synapse.
The Effect of State Medicaid Case‐Mix Payment on Nursing Home Resident Acuity
Authors: Feng Zhanlian , Grabowski David C. , Intrator Orna , Mor Vincent
Published: April 2006

Objective. To examine the relationship between Medicaid case‐mix payment and nursing home resident acuity.

Data Sources. Longitudinal Minimum Data Set (MDS) resident assessments from 1999 to 2002 and Online Survey Certification and Reporting (OSCAR) data from 1996 to 2002, for all freestanding nursing homes in the 48 contiguous U.S. states.

Study Design. We used a facility fixed‐effects model to examine the effect of introducing state case‐mix payment on changes in nursing home case‐mix acuity. Facility acuity was measured by aggregating the nursing case‐mix index (NCMI) from the MDS using the Resource Utilization Group (Version III) resident classification system, separately for new admits and long‐stay residents, and by an OSCAR‐derived index combining a range of activity of daily living dependencies and special treatment measures.

Data Collection/Extraction Methods. We followed facilities over the study period to create a longitudinal data file based on the MDS and OSCAR, respectively, and linked facilities with longitudinal data on state case‐mix payment policies for the same period.

Principal Findings. Across three acuity measures and two data sources, we found that states shifting to case‐mix payment increased nursing home acuity levels over the study period. Specifically, we observed a 2.5 percent increase in the average acuity of new admits and a 1.3 to 1.4 percent increase in the acuity of long‐stay residents, following the introduction of case‐mix payment.

Conclusions. The adoption of case‐mix payment increased access to care for higher acuity Medicaid residents.
Topiramate Does Not Affect the Acquisition or Expression of Ethanol Conditioned Place Preference in DBA/2J or C57BL/6J Mice
Authors: Gremel Christina M. , Gabriel Kara I. , Cunningham Christopher L.
Published: April 2006

Background: Topiramate, an anticonvulsant, has been reported to increase the number of abstinent days and decrease craving in alcohol‐dependent individuals. However, the neurobiological basis for topiramate's effect is unknown. To assess topiramate's effect on ethanol's rewarding and conditioning rewarding effects, the present experiments examined the effects of topiramate on the acquisition and expression of ethanol‐induced conditioned place preference (CPP) in DBA/2J and C57BL/6J mice.

Methods: A biased apparatus and subject assignment were used. Mice received ethanol (2 g/kg) or saline paired with an initially nonpreferred floor (CS+) and saline paired with an initially preferred floor (CS−) for 5‐minute conditioning trials. During the acquisition experiments, mice received a pretreatment of topiramate (0, 5, 10, 20, 50, or 100 mg/kg) 1 hour before the CS+ trials. On intervening CS− trials, mice received a pretreatment of saline. For the preference test, all mice received saline injections and were placed on a split floor for a 30‐minute test. During the expression experiments, mice received no drug pretreatment on conditioning trials, but were pretreated with topiramate (0, 10, 50, or 100 mg/kg) 1 hour before the test session.

Results: Ethanol‐induced CPP was observed in both strains, but topiramate did not affect the acquisition or expression of ethanol‐induced CPP in either strain. Despite its failure to alter CPP, topiramate produced dose‐dependent locomotor activating effects in both strains. These effects were observed both in the presence and in the absence of ethanol.

Conclusions: These findings indicate that topiramate has no effect on ethanol's rewarding or conditioned rewarding effects as indexed by the place conditioning procedure. Thus, these studies raise the possibility that topiramate's efficacy in the treatment of alcoholism results from its impact on brain areas other than those that mediate ethanol's rewarding or conditioned rewarding effects. One alternative possibility is that topiramate decreases withdrawal‐induced negative affective states that normally contribute to relapse.