bluuebunny/crossref_metadata_2025 huggingface dataset:
Flow around a short horizontal bottom cylinder under steady and oscillatory flows
Authors: Testik F. Y. , Voropayev S. I. , Fernando H. J. S.
Published: March 2005

This paper presents the results of an experimental study on flow around a short cylinder placed horizontally on a solid bottom. The aim was to provide a better understanding of flow past blunt objects immersed in the oceanic wave boundary layer. Both steady and oscillatory flows are considered. In the parameter range studied (Reynolds number Re=300–5300, Keulegan–Carpenter number KC=4–31), the near wake was dominated by large periodically shed horseshoe vortices of size comparable to that of the cylinder. In oscillatory flow, horseshoe vortices of opposite sign form periodically on both sides of the cylinder, and they flip from one side of the cylinder to the other with the change of flow direction. This flipping vortex (of one sign) of a given phase of a cycle interacts with the vortex (of opposite sign) that forms in the opposite phase, and the pair is shed away periodically from the cylinder. Flow visualization and particle image velocimetry were used to identify and quantify these flow structures.
Two-photon absorption in the relativistic four-component Hartree–Fock approximation
Authors: Henriksson Johan , Norman Patrick , Jensen Hans Jørgen Aa.
Published: March 2005

A first implementation of the single residue of the quadratic response function in the four-component Hartree–Fock approximation is presented. The implementation is based on a Kramers paired molecular orbital basis and takes full advantage of time and spatial symmetry reductions in a quaternion formulation—in analogy with the previous work on the quadratic response function [J. Chem. Phys. 121, 6145 (2004)]. Sample calculations are given in terms of the monochromatic and coherent two-photon absorption cross sections in the noble gases. The relativistic two-photon selection rule ΔJ={0,±2} allows for nonrelativistically spin-forbidden transitions, and, even in neon, strong two-photon absorption is shown to occur for the XS01→2P23 transition. It is argued that relevant comparisons between nonrelativistic and relativistic calculations must be performed at the level of integrated absorption cross sections.
Free energy profile along a discretized reaction path via the hyperplane constraint force and torque
Authors: Kudin Konstantin N. , Car Roberto
Published: March 2005

By employing mechanical work analogies, we derive a convenient computational approach for evaluation of the free energy profile (FEP) along some discretized path defined as a sequence of hyperplanes. A hyperplane is fully specified by any of its point and a tangent vector. The FEP is obtained as an integral of two components. The translational component of the free energy is computed by integrating the hyperplane constraint force. The rotational component is evaluated via the hyperplane torque. Both ingredients—the constraint force and the hyperplane torque—are evaluated on each hyperplane independently. The integration procedure utilizes a set of reference points defining a point of rotation on each hyperplane, and these points can be chosen before or after the sampling takes place. A shift in the reference points redistributes the FEP contributions between the translational and rotational components. For systems where the FEP is dominated by the potential energy differences, reference points residing on the minimum energy path present a natural choice. We demonstrate the validity of our approach on two examples, a simple two-dimensional (2D) potential, and a seven-atom Lennard-Jones cluster. In each case, we compare the numerical FEP with the harmonic approximation estimates. Our results for the 2D potential are also verified by the data available in the literature. In both cases, the rotational component of the FEP represents a sizable contribution to the total FEP, so ignoring it would yield clearly incorrect results.
Dynamically forced cantilever system: A piezo-polymer characterization tool with possible application for micromechanical HF resonator devices
Authors: Schwödiauer Reinhard
Published: March 2005

A cantilever system, driven to a dynamically forced oscillation by a small piezoelectric specimen is presented as a simple and accurate tool to determine the converse dynamic piezocoefficient up to several kHz. The piezoelectric sample is mounted on top of a reflective cantilever where it is free to oscillate without any mechanical constraint. A Nomarsky-interferometer detects the induced cantilever displacement. The presented technique is especially suited for a precise characterization of small and soft piezoelectric polymer-samples with rough surfaces. The capability of the dynamically forced cantilever principle is demonstrated with a LiNbO3 crystal and with a porous ferroelectretic polypropylene foam. Results from measurements between 400 Hz and 5 kHz were found to be in excellent agreement with published values. Additionally, the dynamically forced cantilever principle may possibly improve the sensitivity of some micromechanical cantilever-sensors and it could also be interesting for the design of enhanced micromechanical high frequency mixer filters. Some ideas about are briefly presented.
Force spectroscopy based on temperature controlled atomic force microscope head using piezoresistive cantilevers
Authors: Muševič I. , Kočevar K. , Kržič U. , Carbone G.
Published: March 2005

We have built a double temperature controlled atomic force microscope (AFM) head, based on the force detection using piezoresistive cantilevers. The temperature of the sample is controlled to better than ±2mK in a temperature interval up to 60°C. The force sensitivity is 300pN and is limited by the intrinsic low frequency noise of the piezoresistive cantilevers. By using a colloidal probe of the radius of R≈10μm, the normalized force sensitivity is F∕R≈0.02mN∕m. Although this is comparable to the sensitivity of a surface force apparatus (SFA), the piezoresistive AFM requires only ≈1μl of a fluid material, that is typically 10.000× less compared to the SFA. The capability of the force spectroscopy using a piezoresistive AFM head is illustrated by measuring the structural forces in the nematic liquid crystal.
Compact extreme ultraviolet reflectometer for the characterization of grazing incidence optics based on a gas discharge light source
Authors: Bergmann Klaus , Rosier Oliver , Metzmacher Christof
Published: March 2005

A grazing incidence reflectometer operating in the extreme ultraviolet (EUV) spectral range around 13.5 nm is presented which is making use of a compact xenon pinch plasma light source. The apparatus allows for measuring the absolute reflectivity of a sample for grazing incidence angle in the range from typically 5° to 35° by comparing the EUV diode signal for the reflected light and a reference diode with an accuracy of better than 2%. Design criteria for proper matching of diode apertures and distances with respect to the spatially extended plasma source are presented. The absolute accuracy has been checked by investigating a ruthenium sample with low roughness, which has a reflectivity in the EUV close to the theoretical limit. Comparison to measurements at the EUV-reflectometer of the Physikalisch Technische Bundesanstalt in Berlin at a synchrotron source confirm the absolute accuracy of better than 2% for the reflectivity for the angle interval of interest.
Fabrication and characterization of vertical-type, self-aligned asymmetric double-gate metal-oxide-semiconductor field-effect-transistors
Authors: Masahara Meishoku , Liu Yongxun , Ishii Kenichi , Sakamoto Kunihiro , Matsukawa Takashi , Tanoue Hisao , Kanemaru Seigo , Suzuki Eiichi
Published: March 2005

For gate work function engineering required for ultrathin channel (UTC) double-gate (DG) metal-oxide-semiconductor field-effect-transistor (MOSFET), threshold voltage (Vth) tuning of self-aligned asymmetric (n+–p+) DG MOSFETs have been experimentally investigated in comparison with symmetric (n+–n+) DG MOSFETs. The vertical UTCs (12–32nm) were fabricated on bulk Si substrates by utilizing the novel ion-bombardment-retarded wet etching and the self-aligned asymmetric DGs were formed by employing the tilted ion implantation and anisotropic dry etching. The fabricated vertical asymmetric DG n-MOSFET with the gate length of 100nm clearly exhibits the desirable Vth of +0.1V, in addition to the unique DG MOSFET characteristics of the high short-channel-effect immunity with decreasing a channel thickness.
Parent‐child relationships and quality of life: Resilience among childhood cancer survivors*
Authors: Orbuch Terri L. , Parry Carla , Chesler Mark , Fritz Jennifer , Repetto Paula
Published: March 2005

Abstract: According to The Resiliency Model of Family Stress, Adjustment, and Adaptation, certain family strengths can promote positive outcomes for children undergoing adverse or stressful circumstances. We proposed that chief among these potential strengths are high quality parent‐child relationships. Data from self‐report questionnaires from 190 long‐term survivors (3+ years posttreatment) of childhood cancer were analyzed. The findings indicated that survivors who report better relationships with their mothers and fathers consistently report a higher quality of life, especially in the psychological domain. Although survivors reported better relationships with their mothers than with their fathers, father‐child relations were associated more highly with survivors’ reports of selective quality of life scales. Important implications for family therapists and practitioners are discussed, especially those that employ a growth or resilience approach.
The family of origin parachute model: Landing safely in adult romantic relationships*
Authors: Busby Dean M. , Gardner Brandt C. , Taniguchi Narumi
Published: March 2005

Abstract: This study investigates the utility of the family of origin parachute model in predicting longitudinal outcomes for couples in romantic relationships. This conceptual model contains common family variables that are theoretically and empirically related to later adult functioning and are believed to influence attitudes that adult children develop regarding romantic relationships as well as self‐esteem. Data from two samples were used to analyze this model. The results support the model and demonstrate its ability to predict membership in relationship satisfaction groups. Suggestions are presented for integrating the family of origin in applied work.
THE BLACK‐SCHOLES EQUATION REVISITED: ASYMPTOTIC EXPANSIONS AND SINGULAR PERTURBATIONS
Authors: Widdicks Martin , Duck Peter W. , Andricopoulos Ari D. , Newton David P.
Published: March 2005

In this paper, novel singular perturbation techniques are applied to price European, American, and barrier options. Employment of these methods leads to a significant simplification of the problem in all cases, by reducing the number of parameters. For American options, the valuation problem is reduced to a procedure that may be performed on a rudimentary handheld calculator. The method also sheds light on the evolution of option prices for all of the cases considered, the results being particularly illuminating for American and barrier options.
Calculus‐like deposit on the apical external root surface of teeth with post‐treatment apical periodontitis: report of two cases
Authors: Ricucci D. , Martorano M. , Bate A. L. , Pascon E. A.
Published: March 2005

Aim  To report two cases in which calculus‐like material was found on external root surfaces of (i) an extracted root and (ii) an apicected part of a root, both of which were removed due to post‐treatment refractory apical periodontitis.

Summary  In each case, there was a fistulous tract, which did not heal after conventional root canal treatment. The first case did not heal even after apical surgery, and subsequent tooth extraction revealed calculus‐like material on a root surface of complex anatomy. The second case showed radiographic signs of healing after apicectomy. Histology of the apical biopsy revealed a calculus‐like material on the external surface of the root apex. It is suggested that the presence of calculus on the root surfaces of teeth with periapical lesions may contribute towards the aetiology of failure.

Key learning points

• Biofilm on the external root surface has been implicated in the failure of apical periodontitis to heal, despite adequate root canal treatment.

• Calculus‐like material was found, in two cases, on the root surface of teeth with post‐treatment apical periodontitis, where the only communication externally was a sinus tract.
Identification of a novel A2 allele derived from the A transferase gene through a nucleotide substitution G539C
Authors: Chen D.‐P. , Tseng C.‐P. , Wang W.‐T. , Sun C.‐F.
Published: March 2005

Background and Objectives  The A2 is a very rare phenotype in the ABO blood group system in the Oriental population. It corresponds to a special ABO allele encoding a glycosyltransferase that is capable of synthesizing A2 antigens, which is weaker than the typical A antigen. In this study, we report a novel A2 allele in two unrelated Taiwanese individuals.

Materials and Methods  Two individuals were identified as the A2 phenotype based on the standard ABO serological test. For analysing the A2 allele, both direct sequencing and gene cloning of the ABO gene were performed.

Results  The ABO gene of the two A2 individuals was composed of O1 and A2 alleles, and the novel A2 allele has a 539G > C that results in the amino acid change Arg180Pro. The mutation was not detected in the general group A population.

Conclusion  We report for the first time that a 539G > C mutation represents a new molecular basis for the A2 blood type. The amino acid substitution from arginine to proline may have effect on the expression of A antigen.
Explaining the Younger– Older Worker Union Density Gap: Evidence from New Zealand
Authors: Haynes Peter , Vowles Jack , Boxall Peter
Published: March 2005

This paper uses two recent large‐scale surveys in New Zealand to test the various reasons given for lower rates of union membership among younger workers. Younger workers’ disproportionate location in smaller workplaces and those industries where union reach is lowest accounts for a substantial part of their lower union density. Along with the tendency of younger workers to explore their options through labour turnover, this factor offers a much better explanation for the younger‐older worker union density gap than do assertions about a growth in individualism in Generations X and Y.
Oral versus vaginal misoprostol administered one hour before surgical termination of pregnancy: a randomised controlled trial
Authors: Sharma Sunita , el Refaey Hazem , Stafford Michael , Purkayastha Sheila , Parry Marianne , Axby Helen
Published: March 2005

Objective  To assess the efficacy of oral and vaginal misoprostol as cervical priming agents administered 1 hour before first trimester surgical termination of pregnancy.

Design  A randomised controlled trial.

Setting  Chelsea and Westminster Hospital, London.

Population  Pregnant women of 10 weeks or less gestation attending the termination of pregnancy clinic.

Methods  Ninety eligible women were recruited to the study during September 2001 and September 2002. Women were randomised to one of the three groups: misoprostol administered orally (400 μg), misoprostol administered vaginally (800 μg) and standard care (no cervical priming agent) administered prior to surgical termination of pregnancy. Under general anaesthesia, and prior to the operation, a cervical tonometer was used to determine the main outcome measures.

Main outcome measures  Baseline cervical dilatation and the cumulative force required to dilate the cervix from 3 to 9 mm.

Results  There was no significant difference in the mean baseline cervical dilation (P= 0.16) or the cumulative force required to dilate the cervix (P= 0.12) between the three randomised groups.

Conclusion  No cervical priming effects were detectable with oral or vaginal misoprostol administered 1 hour before first trimester surgical termination of pregnancy.
A comparative study of two methods of large loop excision of the transformation zone
Authors: Mossa Mohamed A. , Carter Paul G. , Abdu Salah , Young Martin P.A. , Thomas Valerie A. , Barton Desmond P.J.
Published: March 2005

Objective  To determine whether the conventional large loop excision of the transformation zone (CLLETZ) and the ‘top‐hat’ technique (THLLETZ) differ in (a) completeness of excision of the cervical lesion, (b) depth of cervical tissue excised and (c) adequacy of follow up by cytology and colposcopy.

Design  Retrospective case review.

Setting  University Teaching Hospital, London.

Sample  Five hundred and thirteen consecutive patients matched for age, parity, smoking history and referral cytology who had either CLLETZ (286—5%) or THLLETZ (227—44%) for cervical intraepithelial neoplasia (CIN).

Methods  All procedures were performed or supervised by BSCCP‐accredited colposcopists. All cytology and histology were reviewed by two specialist cytohistopathologists. Cervical stenosis was defined as difficulty in or inability in obtaining an endocervical brush smear.

Main outcome measures  Depth of cervical tissue excised, histology of endocervical margins, post‐LLETZ cytologic and colposcopic findings.

Results  The mean depth of excision in the CLLETZ group was 12.1 mm (SD = 4.4 mm) and 20.8 mm (SD = 6.4 mm) in the THLLETZ group. The incidence of involved endocervical margins was 2.8% in the CLLETZ group and 5.2% in the THLLETZ group (P= 0.1). There was CIN in the ‘top‐hat specimen’ of 10 THLLETZ cases (4.4%, CI = 95%). The first post‐treatment cervical smear was inadequate in 5 (4.1%) cases in the CLLETZ group and 20 (11.7%) in the THLLETZ group (P= 0.022). Cervical stenosis was found in 21 (7.7%) cases in the CLLETZ group and in 64 (30.9%) cases in the THLLETZ group (P < 0.0001). Eleven (4%) patients in the CLLETZ group had cytological and/or colposcopic evidence of residual CIN compared with 12(5.8%) patients in THLLETZ group (P= 0.4). In the first follow up assessment, 21.7% of the CLLETZ group had incomplete colposcopy compared with 48.7% in the THLLETZ group (P < 0.0001).

Conclusions  Compared with the CLLETZ, the THLLETZ (1) removed more cervical tissue but did not have a lower incidence of involved endocervical margins, and (2) resulted in significantly higher incidence of inadequate post‐treatment colposcopic and cytological follow up. These data indicate that there is no justification to performing a ‘top‐hat’ LLETZ routinely.
Effects of maternal hypoxia or nutrient restriction during pregnancy on endothelial function in adult male rat offspring
Authors: Williams Sarah J. , Hemmings Denise G. , Mitchell Jana M. , McMillen I. Caroline , Davidge Sandra T.
Published: March 2005

Compromised fetal growth impairs vascular function; however, it is unclear whether chronic hypoxia in utero affects adult endothelial function. We hypothesized that maternal hypoxia (H, 12% O2, n= 9) or nutrient restriction (NR, 40% of control, n= 7) imposed from day 15–21 pregnancy in rats would impair endothelial function in adult male offspring (relative to control, C, n= 10). Using a wire myograph, endothelium‐dependent relaxation in response to methacholine was assessed in small mesenteric arteries from 4‐ and 7‐month‐old (mo) male offspring. Nitric oxide (NO) mediation of endothelium‐dependent relaxation was evaluated using Nω‐nitro‐l‐arginine methyl ester (l‐NAME; NO synthase inhibitor). Observed differences in the NO pathway at 7 months were investigated using exogenous superoxide dismutase (SOD) to reduce NO scavenging, and sodium nitroprusside (SNP; NO donor) to assess smooth muscle sensitivity to NO. Sensitivity to methacholine‐induced endothelium‐dependent relaxation was reduced in H offspring at 4 months (P < 0.05), but was not different among groups at 7 months. l‐NAME reduced methacholine sensitivity in C (P < 0.01), H (P < 0.01) and NR (P < 0.05) offspring at 4 months, but at 7 months l‐NAME reduced sensitivity in C (P < 0.05), tended to in NR (P= 0.055) but had no effect in H offspring. SOD did not alter sensitivity to methacholine in C, but increased sensitivity in H offspring (P < 0.01). SNP responses did not differ among groups. In summary, prenatal hypoxia, but not nutrient restriction impaired endothelium‐dependent relaxation at 4 months, and reduced NO mediation of endothelial function at 7 months, in part through reduced NO bio‐availability. Distinct effects following reduced maternal oxygen versus nutrition suggest that decreased oxygen supply during fetal life may specifically impact adult vascular function.
Sweet Bird Most Musical
Authors: Lohr Bernard
Published: March 2005

Nature's Music
The Science of Birdsong.
Peter Marler and Hans Slabbekoorn, Eds.
. Elsevier Academic Press, San Diego, 2004. 543 pp. + 2 CD-ROMS. $74.95, £49.95. ISBN 0-12-473070-1.

Covering topics such as the physiology, neurobiology, learning, ecology, and evolution of birdsong, the contributors offer nonspecialists an up-to-date survey of our understanding of avian singing.
Shining a Light on Semiconductors
Authors: Chelikowsky James R.
Published: March 2005

The Story of Semiconductors
.
By John Orton
. Oxford University Press, Oxford, 2004. 522 pp. $54.50, £35. ISBN 0-19-853083-8.

Surveying the physics, devices, and applications of semiconductors, Orton offers a historical perspective that highlights interactions among research, industry, and consumer demands.
Differential regulation of intestinal alkaline phosphatase gene expression by Cdx1 and Cdx2
Authors: Alkhoury Fuad , Malo Madhu S. , Mozumder Moushumi , Mostafa Golam , Hodin Richard A.
Published: March 2005

We have examined the role that the caudal-related homeobox transcription factors Cdx1 and Cdx2 play in activating the enterocyte differentiation marker gene intestinal alkaline phosphatase ( IAP). Human colon cancer Caco-2 cells were transiently transfected with Cdx1 and/or Cdx2, and semiquantitative RT-PCR was used to study the effects on IAP mRNA expression. Transfections with a variety of IAP-luciferase reporter constructs were used to identify a Cdx response element located within the human IAP gene promoter. Protein-DNA interactions were examined by EMSA. Results showed that Cdx1 markedly induced IAP mRNA expression, whereas Cdx2 did not, and, in fact, inhibited the Cdx1 effects. Functional analysis revealed that Cdx1 transactivates (fourfold, P < 0.05) the IAP promoter through a novel Cdx response element (GTTTAGA) located between −2369 and −2375 upstream of the translational start site. EMSA showed that both Cdx1 and Cdx2 could bind to the cis element, but in cotransfection experiments, Cdx2 inhibited the Cdx1 effects by ∼50%. Thus we have identified a previously unrecognized interaction between two important gut transcription factors, Cdx1 and Cdx2, in the context of IAP gene regulation. Cdx1 activates the IAP gene via a novel cis element, whereas Cdx2 inhibits the Cdx1 effects.
Regulation of the Renal Sodium-Dependent Phosphate Cotransporter NaPi2 (Npt2) in Acute Renal Failure due to Ischemia and Reperfusion
Authors: Rubinger Dvora , Wald Hanna , Gimelreich Dimitri , Halaihel Nabil , Rogers Thomas , Levi Moshe , Popovtzer Mordecai M.
Published: March 2005

Background: Acute renal failure (ARF) is associated with hyperphosphatemia and decreased urinary phosphate excretion. The present study was undertaken to characterize the effects of ARF due to ischemia and reperfusion on renal phosphate transport and on gene and pro- tein expression of type IIa NaPi cotransporter (Npt2) the physiologically most relevant renal sodium-dependent phosphate cotransporter. Methods: The following groups of rats with intact parathyroid glands were studied: (1) sham operated (sham); (2) after 1 h ischemia by bilateral renal artery clamping (I), and after 1 h ischemia and reperfusion of 1 h (I + R 1 h); (3) 24 h (I + R 24 h); (4) 48 h (I + R 48 h), and (5) 72 h (I + R 72 h) duration. The effect of ARF on Npt2 mRNA and protein expression was also examined after parathyroidectomy (PTX) of 2 and 4 days’ duration. Results: Ischemia and reperfusion were associated with increases in plasma creatinine, hyperphosphatemia, and with decreased tubular phosphate reabsorption. Npt2 mRNA was significantly downregulated in the cortex, maximal at 24 and 48 h of reperfusion. The degree of Npt2 mRNA downregulation was not affected by PTX of 2–4 days’ duration. The abundance of Npt2 protein in proximal tubular apical brush border membrane was markedly decreased after reperfusion. Npt2 protein, however, was more abundant in PTX animals than in those with intact parathyroids and a similar degree of renal insufficiency. The immunohistochemical analysis of proximal tubular apical brush border membrane showed a progressive decrease of Npt2 protein labeling after ischemia and reperfusion, with progressive regeneration after 72 h. Conclusion: These results suggest that downregulation of Npt2 protein may contribute to the decreased tubular reabsorption of phosphate in acute ischemic renal failure and hyperphosphatemia.
The EPAGE Internet Guideline as a Decision Support Tool for Determining the Appropriateness of Colonoscopy
Authors: Terraz Olivier , Wietlisbach Vincent , Jeannot Jean-Gabriel , Burnand Bernard , Froehlich Florian , Gonvers Jean-Jacques , Harris Jennifer K. , Vader John-Paul
Published: March 2005

Background: Few studies have examined how physicians perceive guidelines, much less their perceptions of an Internet presentation of such guidelines. This study assessed physicians’ acceptance ofan Internet-based guideline on the appropriateness of colonoscopy. Methods: Gastroenterologists participating in an international observational study consulted an Internet-based guideline for consecutive patients referred for colonoscopy. The guideline was produced by the European Panel on the Appropriateness of Gastrointestinal Endoscopy (EPAGE), using a validated method (RAND). Through the use of questionnaires, physicians were asked their opinions and perspectives of the guideline and website. Results: There were 289 patients included in the study. The mean time for consulting the website was 1.8 min, and it was considered easy to use by 86% of physicians. The recommendations were easily located for 82% of patients and physicians agreed with the appropriateness in 86% of cases. According to the EPAGE criteria, colonoscopy was appropriate, uncertain, and inappropriate in 59, 28, and 13% of patients, respectively. Conclusions: The EPAGE guideline was considered acceptable and user-friendly and the use, usefulness and relevance of the website were considered acceptable. However, its actual use will depend on the removal of certain organizational and cultural obstacles.
The Marshall Plan and the Division of Europe
Authors: Maier Charles S.
Published: March 2005

Five distinguished scholars offer separate commentaries on the article by Michael Cox and Caroline Kennedy-Pipe. All of the commentators reject the broad interpretation and many of the specific arguments put forth by Cox and Kennedy-Pipe. They point out several crucial issues that are omitted from the article and raise questions about the authors' sources, use of evidence, and selective invocation of secondary literature. They regret that Cox and Kennedy Pipe seem to dwell on a large number of the same matters that preoccupied radical revisionist historians in the 1960s. They argue that although Cox and Kennedy-Pipe offer a more sophisticated version of revisionism, their article suffers from many of the same shortcomings. Most of the commentators believe that the Marshall Plan merely reflected a division of Europe that was already well under way rather than being the precipitating cause. In that sense, the debate on the origins of the Cold War needs to go well beyond the issues raised by Cox and Kennedy-Pipe.
After 9/11
Authors: Enders Walter , Sandler Todd
Published: March 2005

Using time-series procedures, the authors investigate whether transnational terrorism changed following 9/11 and the subsequent U.S.-led “war on terror.” Perhaps surprising, little has changed in the time series of overall incidents and most of its component series. When 9/11 is prejudged as a break date, the authors find that logistically complex hostage-taking events have fallen as a proportion of all events, while logistically simple, but deadly, bombings have increased as a proportion of deadly incidents. These results hold when they apply the Bai-Perron procedure in which structural breaks are data identified. This procedure locates earlier breaks in the mid-1970s and 1990s. Reasonable out-of-sample forecasts are possible if structural breaks are incorporated fairly rapidly into the model.
CCR6 regulates CD4+ T-cell–mediated acute graft-versus-host disease responses
Authors: Varona Rosa , Cadenas Vanesa , Gómez Lucio , Martínez-A Carlos , Márquez Gabriel
Published: March 2005

We studied the role of chemokine receptor CCR6 in acute graft-versus-host disease (GvHD), a pathology in which activated, host antigen-specific donor T cells selectively damage tissues such as skin, liver, and gut. GvHD incidence was reduced in major histocompatibility complex (MHC) class II–mismatched recipients of CD4+ T cells from CCR6-deficient donors. In MHC-matched/minor histocompatibility antigen–mismatched recipients of CD4+CD45RBhigh T cells from CCR6-deficient donors, infiltration of CD45+ and CD4+ cells to skin and gut, as well as lesion onset, were significantly delayed, and pathologic symptoms were milder. Consistent with this, in skin and gut of recipients of naive T cells from CCR6-deficient donors we observed lower levels of interferon γ (IFN-γ), interleukin 10 (IL-10), and the chemokines that control activated T-cell homing. We suggest a role for CCR6 in recruiting alloreactive CD4+ T cells to target tissues and identify CCR6 as a potential therapeutic target for GvHD.
Variation in the cortical area map of C57BL/6J and DBA/2J inbred mice predicts strain identity
Authors: Airey David C , Robbins Alicia I , Enzinger Katherine M , Wu Fangbai , Collins Christine E
Published: March 2005

Background

Recent discoveries suggest that arealization of the mammalian cortical sheet develops in a manner consonant with principles established for embryonic patterning of the body. Signaling centers release morphogens that determine regional growth and tissue identity by regulating regional expression of transcription factors. Research on mouse cortex has identified several candidate morphogens that affect anteroposterior or mediolateral cortical regionalization as well as mitogenesis. Inbred strains of laboratory mice can be exploited to study cortical area map formation if there are significant phenotypic differences with which to correlate gene polymorphism or expression data. Here we describe differences in the cortical area map of two commonly used inbred strains of laboratory mice, C57BL/6J and DBA/2J. Complete cortical hemispheres from adult mice were dissected and stained for the cytochrome oxidase enzyme in order to measure histochemically defined cortical areas.

Results

C57BL/6J has the larger neocortex, relatively larger primary visual cortex (V1), but relatively smaller posterior medial barrel subfield of the primary somatosensory cortex (PMBSF). The sample of C57BL/6J and DBA/2J mice can be discriminated with 90% accuracy on the basis of these three size dimensions.

Conclusion

C57BL/6J and DBA/2J have markedly different cortical area maps, suggesting that inbred strains harbor enough phenotypic variation to encourage a forward genetic approach to understanding cortical development, complementing other approaches.
Risk factors for bacterial catheter colonization in regional anaesthesia
Authors: Morin Astrid M , Kerwat Klaus M , Klotz Martina , Niestolik Roswitha , Ruf Veronika E , Wulf Hinnerk , Zimmermann Stefan , Eberhart Leopold HJ
Published: March 2005

Background

Although several potential risk factors have been discussed, risk factors associated with bacterial colonization or even infection of catheters used for regional anaesthesia are not very well investigated.

Methods

In this prospective observational trial, 198 catheters at several anatomical sites where placed using a standardized technique. The site of insertion was then monitored daily for signs of infection (secretion at the insertion site, redness, swelling, or local pain). The catheters were removed when clinically indicated (no or moderate postoperative pain) or when signs of potential infection occurred. After sterile removal they were prospectively analyzed for colonization, defined as > 15 colony forming units.

Results

33 (16.7%) of all catheters were colonized, and 18 (9.1%) of these with additional signs of local inflammation. Two of these patients required antibiotic treatment due to superficial infections. Stepwise logistic regression analysis was used to identify factors associated with catheter colonization. Out of 26 potential factors, three came out as statistically significant. Catheter placement in the groin (odds-ratio and 95%-confidence interval: 3.4; 1.5–7.8), and repeated changing of the catheter dressing (odds-ratio: 2.1; 1.4–3.3 per removal) increased the risk for colonization, whereas systemic antibiotics administered postoperatively decreased it (odds ratio: 0.41; 0.12–1.0).

Conclusion

Colonization of peripheral and epidural nerve catheter can only in part be predicted at the time of catheter insertion since two out of three relevant variables that significantly influence the risk can only be recorded postoperatively. Catheter localisation in the groin, removal of the dressing and omission of postoperative antibiotics were associated with, but were not necessarily causal for bacterial colonization. These factors might help to identify patients who are at increased risk for catheter colonization.
Validity of Simpson-Angus Scale (SAS) in a naturalistic schizophrenia population
Authors: Janno Sven , Holi Matti M , Tuisku Katinka , Wahlbeck Kristian
Published: March 2005

Background

Simpson-Angus Scale (SAS) is an established instrument for neuroleptic-induced parkinsonism (NIP), but its statistical properties have been studied insufficiently. Some shortcomings concerning its content have been suggested as well. According to a recent report, the widely used SAS mean score cut-off value 0.3 of for NIP detection may be too low. Our aim was to evaluate SAS against DSM-IV diagnostic criteria for NIP and objective motor assessment (actometry).

Methods

Ninety-nine chronic institutionalised schizophrenia patients were evaluated during the same interview by standardised actometric recording and SAS. The diagnosis of NIP was based on DSM-IV criteria. Internal consistency measured by Cronbach's α, convergence to actometry and the capacity for NIP case detection were assessed.

Results

Cronbach's α for the scale was 0.79. SAS discriminated between DSM-IV NIP and non-NIP patients. The actometric findings did not correlate with SAS. ROC-analysis yielded a good case detection power for SAS mean score. The optimal threshold value of SAS mean score was between 0.65 and 0.95, i.e. clearly higher than previously suggested threshold value.

Conclusion

We conclude that SAS seems a reliable and valid instrument. The previously commonly used cut-off mean score of 0.3 has been too low resulting in low specificity, and we suggest a new cut-off value of 0.65, whereby specificity could be doubled without loosing sensitivity.
Differential expression of CCN-family members in primary human bone marrow-derived mesenchymal stem cells during osteogenic, chondrogenic and adipogenic differentiation
Authors: Schutze Norbert , Noth Ulrich , Schneidereit Jutta , Hendrich Christian , Jakob Franz
Published: March 2005

Background

The human cysteine rich protein 61 (CYR61, CCN1) as well as the other members of the CCN family of genes play important roles in cellular processes such as proliferation, adhesion, migration and survival. These cellular events are of special importance within the complex cellular interactions ongoing in bone remodeling. Previously, we analyzed the role of CYR61/CCN1 as an extracellular signaling molecule in human osteoblasts. Since mesenchymal stem cells of bone marrow are important progenitors for various differentiation pathways in bone and possess increasing potential for regenerative medicine, here we aimed to analyze the expression of CCN family members in bone marrow-derived human mesenchymal stem cells and along the osteogenic, the adipogenic and the chondrogenic differentiation.

Results

Primary cultures of human mesenchymal stem cells were obtained from the femoral head of patients undergoing total hip arthroplasty. Differentiation into adipocytes and osteoblasts was done in monolayer culture, differentiation into chondrocytes was induced in high density cell pellet cultures. For either pathway, established differentiation markers and CCN-members were analyzed at the mRNA level by RT-PCR and the CYR61/CCN1 protein was analyzed by immunocytochemistry.

RT-PCR and histochemical analysis revealed the appropriate phenotype of differentiated cells (Alizarin-red S, Oil Red O, Alcian blue, alkaline phosphatase; osteocalcin, collagen types I, II, IX, X, cbfa1, PPARγ, aggrecan). Mesenchymal stem cells expressed CYR61/CCN1, CTGF/CCN2, CTGF-L/WISP2/CCN5 and WISP3/CCN6. The CYR61/CCN1 expression decreased markedly during osteogenic differentiation, adipogenic differentiation and chondrogenic differentiation. These results were confirmed by immuncytochemical analyses. WISP2/CCN5 RNA expression declined during adipogenic differentiation and WISP3/CCN6 RNA expression was markedly reduced in chondrogenic differentiation.

Conclusion

The decrease in CYR61/CCN1 expression during the differentiation pathways of mesenchymal stem cells into osteoblasts, adipocytes and chondrocytes suggests a specific role of CYR61/CCN1 for maintenance of the stem cell phenotype. The differential expression of CTGF/CCN2, WISP2/CCN5, WISP3/CCN6 and mainly CYR61/CCN1 indicates, that these members of the CCN-family might be important regulators for bone marrow-derived mesenchymal stem cells in the regulation of proliferation and initiation of specific differentiation pathways.
Linguistic sources of item bias for second generation immigrants in Dutch tests
Authors: Uiterwijk Henny , Vallen Ton
Published: March 2005

This article reports the first results of a long-term research project focusing on the detection and possible linguistic causes of differential item functioning (DIF) for second generation immigrant students in the Final Test of Primary Education in the Netherlands. The main aim of the project is to provide test constructors with information which is as detailed as possible about sources of DIF in order to help them avoid item bias in future forms of the test. The project was carried out in three steps. First, DIF items were identified using two statistical procedures: IRT and Mantel-Haenszel. The second stage was an investigation of sources of DIF, beginning with an inventory of subject matter elements which can cause difficulty for immigrant students, according to previous educational research. This was followed by a careful evaluation of DIF items by the researchers and by external experts, and a think-aloud experiment with students. At the third stage, judges decided whether each DIF item was biased and thus reduced the construct validity of the test. The article concentrates on the classification of linguistic sources of DIF and a consideration of whether they work to the advantage or disadvantage of immigrant students.
Immunotoxicity evaluation of nelfinavir in rats
Authors: Burns-Naas Leigh Ann , White Kimber L , McCay J Ann , Ivett James , Webber Stephanie , Zorbas Mark
Published: March 2005

The objective of these investigations was to determine whether exposure to the HIV-1 protease inhibitor nelfinavir compromises immune function in Sprague Dawley rats. Animals (20/sex per group) were exposed orally for 1 or 6 months to nelfinavir at doses of 0 (1% carboxymethylcellulose vehicle), 100, 300 or 1000 mg/kg per day. Animals were observed daily for morbidity/mortality and for clinical signs of toxicity. Body weights were recorded weekly (weeks 1-14) and then monthly there-after and at study termination. At termination (1 month or 6 months; 10/sex per group), serum was collected and retained for toxicokinetic analysis. The spleen, thymus and liver were removed from each animal and weighed; thymuses and liver were discarded after weighing. Spleens were prepared and immunophenotyping, natural killer (NK) cell activity, and proliferative responses to mitogenic stimuli (e.g., concanavalin A, Salmonella typhimurium) were evaluated. There were no treatment-related effects on immune cell populations (absolute or percent values) or in proliferative responses. At the 1-month interval, a decrease in NK cell activity (0.45-fold control) was noted in male rats at 100 and 1000 mg/kg per day but not at the middle dose of 300 mg/kg per day. Female rats at 1 month were noted for an increase in NK cell activity (1.4-fold control) at 100 mg/kg per day, but there was no difference in the NK response between vehicle-treated animals and those exposed to higher doses of nelfinavir. No effects on NK activity were noted in female animals after 6 months of nelfinavir treatment. Assay difficulties prevented evaluation of male rats at the 6-month interval. Taken together, the absence of a dose-response effect for NK activity in male rats treated for 1 month, the lack of suppressive effects in females treated for either 1 or 6 months, and the unchanged splenic NK cell numbers in nelfinavir-treated animals at both 1 and 6 months suggest that the decreased NK activity noted in male rats at 1 month is not biologically relevant. It was therefore concluded that, under the experimental conditions used, oral treatment with nelfinavir for 1 or 6 months at doses up to 1000 mg/ kg per day is not immunosuppressive in rats. C8hr values following nelfinavir treatment at 1000 mg/kg per day for 6 months were between 1-and 2.7-fold the reported Cmaxvalues in humans.
Investigations on the subchronic toxicity of 2-methoxypropanol-1(acetate) in rats
Authors: Ma-Hock L , Klimisch H-J , Gembardt Chr , Deckardt K , Jäckh R
Published: March 2005

Wistar rats were exposed to 2-methoxypropylacetate-1 (2-MPAc-1) vapours in concentrations of 0, 110, 560 and 2800 ppm for (equiv. to 0; 0.6; 3.0 and 14.9 mg/L) for 4 weeks in chambers (6 hours/day; 5 days/week; five male and five female animals per group). The top concentration was equivalent to a 95% vapour saturation at 208C and the animals reacted to this with a moderate respiratory irritation during the 6 hours exposure times; at 560 ppm these effects were only slight. The top dose was also associated with a significantly reduced body weight development and some hematologic and biochemical alterations of little specificity. The most prominent effect was thymic atrophy. No effects were noted on the testes or on the cellularity in blood or bone marrow. 560 ppm were without systemic effects.

Furthermore, 2-methoxypropanol-1 (2-MP-1), 2-MPAc-1 and 2-ethoxyethanol (EE) were administered in parallel by gavage to groups of five male Wistar rats daily for 10 days at near equimolar dose levels (1800, 2600 and 1800 mg/kg per day, respectively). At the end of the administration period the testes were investigated. There was a pronounced testicular atrophy in animals exposed to EE, whereas no adverse effects were observed with 2-MP-1 and 2-MPAc-1.

The results of these studies indicate that 2-MP-1 and 2-MPAc-1 which previously had been shown to exert pronounced prenatal toxicity in rabbits and weak prenatal effects in rats are devoid of other forms of systemic toxicity in rats that are typically observed with ethoxyethanol and methoxyethanol.
Psychopathy versus psychopathies in classifying criminal offenders
Authors: Vassileva Jasmin , Kosson David S. , Abramowitz Carolyn , Conrod Patricia
Published: March 2005

Purpose. Psychopathy has been shown to be related to the onset, frequency, and course of antisocial behaviour in criminal offenders. The purpose of the present study was to use cluster analysis to explore the existence of subtypes of criminal offenders in male inmates, based on the two empirically validated dimensions of psychopathy and several other dimensions previously proposed for differentiating offender groups.

Methods. Two hundred male inmates participated in the study. Scores on the two dimensions of the Psychopathy Checklist–Revised (Hare, 1991), the Interpersonal Measure of Psychopathy (Kosson, Steuerwald, Forth, & Kirkhart, 1997), DSM‐IV diagnoses for alcohol and drug abuse/dependence, and anxiety were standardized and were included in two different types of cluster analyses. Both Ward's hierarchical method and K‐means non‐hierarchical method revealed the presence of four subtypes of criminal offenders in the sample. The four‐cluster solution was replicated when the sample was split in half and identical cluster analyses were performed on the two subsamples.

Results. Two types of cluster analyses identified four subtypes of criminal offenders in two samples of jail inmates. Two of the clusters resembled primary and secondary psychopaths described in the literature, the third group exhibited some antisocial and psychopathic features, and the fourth group was non‐psychopathic.

Conclusions. Findings suggest that considering the individual contributions of the two dimensions of psychopathy in lieu of the construct as a whole may prove useful in identifying relatively homogeneous groups of criminal offenders.
Gums
Authors: BeMiller James N.
Published: March 2005

The term gum most often refers to natural and modified polysaccharides, other than starches and modified starch products, that thicken or gel aqueous systems. Polysaccharides that comprise the category of substances called gums have a variety of structures and impart a variety of functionalities, in addition to thickening and gelation. Common commercial polysaccharidic gums are algins, carboxymethylcelluloses, carrageenans, gellan, guar gum and modified guar gums, gum arabic, hydroxyethylcelluloses, hydroxypropylmethylcelluloses, locust bean (carob) gum, methylcelluloses, pectins, welan, and xanthan.
Polyethylene, Low Density
Authors: Maraschin Norma
Published: March 2005

Low density polyethylene (LDPE) was the first thermoplastic polyolefin used commercially. It was discovered serendipitously in 1933 and was quickly utilized for radar sheathing during the war. LDPE, along with high density polyethylene (HDPE) and linear low density polyethylene (LLDPE), offers an unparalleled combination of low cost, ease of fabrication into a variety of end uses, and balance of physical properties. Polyethylene has displaced paper, metal, wood, and other materials of construction. LDPE is unique in its polymerization process. Free‐radical‐initiated polymerization is used to make LDPE, as compared to transition‐metal catalysis for HDPE and LLDPE. The free‐radical process leads to the unique molecular structure of LDPE: the presence of long‐chain branching. The long‐chain branching imparts unusual rheological behavior in both shear and extension. LDPE is used in a variety of applications, such as film, coating, molding, and wire and cable insulation. One of the reasons for its wide range of utility is its thermal stability and low toxicity.
Intramolecular Hydroarylation of Alkynes Catalyzed by Platinum or Gold: Mechanism and endo Selectivity
Authors: Nevado Cristina , Echavarren Antonio M.
Published: March 2005

The cyclization of differently substituted aryl alkynes with PtII or AuI catalysts proceeds by endo‐dig pathways. When AgI was used to generate reactive cationic AuI catalysts, 2H‐chromenes dimerize to form cyclobutane derivatives by a AgI‐catalyzed process. A DFT study on the cyclization mechanism shows a kinetic and thermodynamic preference for 6‐endo‐dig versus 5‐exo‐dig cyclizations in PtII‐catalyzed processes. Calculations indicate that although Friedel–Crafts and the cyclopropanation processes via metal cyclopropyl carbenes show very similar activation energies, platinum cyclopropyl carbenes are the stationary points with the lowest energy.