bluuebunny/crossref_metadata_2025 huggingface dataset:
The Stroop revisited: a meta‐analysis of interference control in AD/HD
Authors: Van Mourik Rosa , Oosterlaan Jaap , Sergeant Joseph A.
Published: January 2005

Background:  An inhibition deficit, including poor interference control, has been implicated as one of the core deficits in AD/HD. Interference control is clinically measured by the Stroop Colour‐Word Task. The aim of this meta‐analysis was to investigate the strength of an interference deficit in AD/HD as measured by the Stroop Colour‐Word Task and to assess the role of moderating variables that could explain the results. These moderating variables included: methods of calculating the interference score, comorbid reading and psychiatric disorders, AD/HD‐subtypes, gender, age, intellectual functioning, medication, and sample size.

Methods:  Seventeen independent studies were located including 1395 children, adolescents, and young adults, in the age range of 6–27 years. A meta‐analysis was conducted to assess the effect sizes for the scores on the word and the colour card as well as the interference score.

Results:  Children with AD/HD performed more poorly on all three dependent variables. The effect sizes for word reading (d = .49) and colour naming (d = .58) were larger and more homogeneous than the effect size for the interference score (d = .35). The method used to calculate the interference score strongly influenced the findings for this measure. When interference control was calculated as the difference between the score on the colour card minus the score on the colour‐word card, no differences were found between AD/HD groups and normal control groups.

Discussion:  The Stroop Colour‐Word Task, in standard form, does not provide strong evidence for a deficit in interference control in AD/HD. However, the Stroop Colour‐Word Task may not be a valid measure of interference control in AD/HD and alternative methodologies may be needed to test this aspect of the inhibitory deficit model in AD/HD.
Aggression, social cognitions, anger and sadness in bullies and victims
Authors: Camodeca Marina , Goossens Frits A.
Published: January 2005

Background:  The present study aimed to investigate children's social information processing (SIP) and emotions in the bullying situation, taking into account reactive and proactive aggression. More specifically, we investigated the way in which children interpret social information, which goals they select, how they evaluate their responses and which emotions they express in hypothetical situations.

Method:  The participants comprised 242 Dutch children (120 girls and 122 boys; mean age: 117.2 months), who were assigned by means of peer nominations (Salmivalli, Lagerspetz, et al., 1996) to one of the following roles: bully (n = 21), follower of the bully (n = 38), victim (n = 35), defender of the victim (n = 48), outsider (n = 52) and not involved (n = 32). Sixteen children (including 3 bully/victims) were not given any role. The reactive and proactive aggression scale (Dodge, & Coie, 1987) was filled out by teachers in order to test the association between these types of aggression and involvement in bullying. Children were presented with ambiguous scenarios and responded to questions about attribution of intent, goal selection and emotions (anger and sadness). In addition, two questionnaires were administered to children: one assessed perceived self‐efficacy in performing aggression, inhibiting aggression and using verbal persuasion skills, and the other assessed expected outcomes from behaving aggressively or prosocially.

Results:  Results showed that while reactive aggression was common in bullies and victims, proactive aggression was only characteristic of bullies. Both bullies and victims, compared to the other children, scored higher on hostile interpretation, anger, retaliation and ease of aggression. Bullies and followers claimed that it was easy for them to use verbal persuasion, while victims turned out to be the saddest group. All children, irrespective of their role in the peer group, thought that aggressive as well as prosocial behavior was more likely to produce desired results from a friendly peer than from an aggressive one.

Conclusions:  Bullies and victims seem to be similar in reactive aggression, SIP, and in the expression of anger, but the motivations which lead to their behavior may be different, as well as the final outcomes of their acts.
Foetal testosterone, social relationships, and restricted interests in children
Authors: Knickmeyer Rebecca , Baron‐Cohen Simon , Raggatt Peter , Taylor Kevin
Published: January 2005

Background: Sex‐differences exist in some areas of human social behaviour. In animals, foetal testosterone (fT) plays a central role in organising the brain and in later social behaviour. fT has also been implicated in language development, eye‐contact, and spatial ability in humans.

Methods: Fifty‐eight children (35 male and 23 female), whose fT was analysed in amniotic fluid, were followed up at age 4. Their mothers completed the Children's Communication Checklist, a questionnaire assessing language, quality of social relationships and restricted interests.

Results: fT was negatively correlated to quality of social relationships, taking sex‐differences into account. fT was also positively correlated with restricted interests in boys.

Conclusions: These findings implicate fT in both social development and attentional focus. They may also have implications for understanding the sex ratio in autism.
Practitioner Review: The contribution of attachment theory to child custody assessments
Authors: Byrne James G. , O'Connor Thomas G. , Marvin Robert S. , Whelan William F.
Published: January 2005

Background:  The area of child custody assessments continues to fail to meet the evidence‐based threshold now established in clinical practice. This is despite the existence, for many years, of published guidelines governing the practice of custody assessments available from a number of professional bodies.

Methods:  This article reviews the potential of attachment theory to contribute to the conceptualization of custody evaluations, clinical assessment, and the development of evidence‐based practice. Particular attention is paid to specific instruments used to assess attachment in clinic and non‐clinic settings.

Results:  Guidelines concerning child custody assessments highlight the particular importance of assessing attachment and parent–child relationship quality. However, measures often used in the course of a custody assessment are not backed up with empirical research, and the measures that are supported by empirical research have been slow to influence practice. There may be conceptual and measurement advantages of considering an attachment research‐informed custody assessment.

Discussion:  Attachment theory has obvious conceptual relevance for the child custody context. Further clinical research is needed to demonstrate the usefulness of attachment research measures; research of this kind may shed important light on the development and resilience of affectional bonds.
Methodology, Statistics, and Voting Error: An Exploration of 2000 Presidential Election Data in Two States
Authors: Miller Geralyn M.
Published: January 2005

In the wake of the voting controversy of Election 2000, along with passage of a congressional measure designed to fix what many believe is an ailing voting system, research into the impact of voting equipment on residual voting error has become a crucial question as the states prepare to replace existing voting equipment through the use of matching federal funds, to adjust existing equipment, or to face yet more lawsuits. Most existent studies into the link between voting equipment and residual voting error have concentrated on voting equipment across the states rather than within the individual states, generating results that are subject to a possible aggregation bias. Using a variety of statistical techniques, data on Election 2000 U.S. presidential and U.S. senatorial races are analyzed in an attempt to determine the impact of voting equipment on the voting error levels intrastate in those races. This study presents analysis of two sets of state data, Wyoming and Pennsylvania, and is used to argue that the infamous punch‐card voting equipment may not be a significant contributor to an increase in voter error when analyzing intrastate, contrary to existing research that indicates it is significant when analyzed across multiple states. This research underscores the importance of researchers’ ideological perspectives in application of statistical methodology to the American policy arena.
Policy Coherence and Component‐Driven Policymaking: Arctic Policy in Canada and the United States
Authors: May Peter J. , Jones Bryan D. , Beem Betsi E. , Neff‐Sharum Emily A. , Poague Melissa K.
Published: January 2005

This research extends theorizing about the implications of political environments to the content of policy areas. We consider the case of Arctic policy in Canada and the United States as an example of what we label as component‐driven policymaking. We show how the lack of a clear constituency and the lack of a stable policy subsystem for the Arctic create a policy environment for which the politics of particular issues dominate Arctic policymaking. The result is a policy space labeled Arctic policy that lacks policy coherence. We suggest that similar features of component‐based policymaking help explain limited policy coherence for a variety of policy areas such as policies for children, families, rural areas, urban areas, and women in the United States.
The Effects of Universal Pre‐K in Oklahoma: Research Highlights and Policy Implications
Authors: Gormley William T. , Phillips Deborah
Published: January 2005

Oklahoma is one of only three states in the nation to offer a free pre‐kindergarten (pre‐K) program to all students in participating school districts on a voluntary basis. Fortuitous circumstances in Tulsa, Oklahoma, the state's largest school district, permitted an unusually rigorous evaluation of the pre‐K program in Tulsa. Because four‐year‐olds beginning pre‐K and five‐year‐olds beginning kindergarten were administered the same test in September 2001 and because strict eligibility cut‐offs were applied, based on date of birth, it was possible to control for selection effects, in addition to gender, race/ ethnicity, school lunch eligibility, and precise date of birth. The evaluation showed strong positive effects of the pre‐K program on children's language and cognitive test scores. Hispanic children benefited most from the program, and black children also showed sharp gains, especially when they attended full‐day programs. The results are discussed in light of contemporary controversies regarding targeted or universal pre‐K programs; full‐or part‐day programming; public school or multiple delivery sites; strategies for ensuring high quality, effective programs; and the need for rigorous program evaluations.
Effect of Education on School‐Age Children's and Parents' Asthma Management
Authors: Horner Sharon D.
Published: January 2005

ISSUES AND PURPOSE. Asthma affects 7.4% of school‐age children, with poor children or members of ethnic minorities disproportionately affected.

DESIGN AND METHODS. A quasiexperimental, year‐long pilot study tested the effectiveness of an intervention that included school‐based small‐group education for children with home‐based education for parents. Pretest and two posttest measures were collected.

RESULTS. Forty‐four families completed the study (41% African American, 36% European American, 23% Mexican American), with 46% coming from poor or working‐class families. Asthma management in the treatment group was lower than the comparison group at baseline, but improved significantly at 6 months and stabilized at 12 months, a trend that was most pronounced among the poorer children.

PRACTICE IMPLICATIONS. Improvements in asthma management point to the need for ongoing asthma education to address learning needs of the children and families.
Antibiotic susceptibility of Listeria monocytogenes in Denmark 1958–2001
Authors: HANSEN JOANNA M. , GERNER‐SMIDT PETER , BRUUN BRITA
Published: January 2005

In order to see whether the susceptibility of Danish Listeria monocytogenes strains has changed over the years we examined a collection of human isolates from the period 1958–2001. We, furthermore, wanted to compare L. monocytogenes susceptibility testing using a disc diffusion assay with MIC measurements performed by the E‐test. 106 strains isolated predominantly from blood cultures and cerebrospinal fluids were examined together with three reference strains. Susceptibility to the following antibiotics was tested by the E‐test and by Oxoid discs using Iso‐sensitest agar: penicillin G, ampicillin, meropenem, gentamicin, sulphamethoxazole, trimethoprim, ciprofloxacin, erythromycin, vancomycin, linezolid, chloramphenicol and tetracycline. The strains were in the main sensitive to all antibiotics examined using both methods, except for ciprofloxacin, where the strains were intermediate sensitive. However, for penicillin, ampicillin and sulphamethoxazole, while the disc diffusion assay found the strains to be sensitive, MIC measurements generally placed the strains one dilution above the breakpoint for sensitivity in the intermediate sensitive group. Based on the MIC measurements, the antibiotic susceptibility of L. monocytogenes has not changed in Denmark from 1958 to 2001, and the multiresistant strains found in human infections elsewhere have not been found in Denmark.
Effects of diabetes and CETP expression on diet‐induced atherosclerosis in LDL receptor‐deficient mice
Authors: BERTI JAIRO A. , SALERNO ALESSANDRO G. , BIGHETTI ELIETE J. B. , CASQUERO ANDREA C. , BOSCHERO ANTONIO C. , OLIVEIRA HELENA C. F.
Published: January 2005

The role of CETP expression and diabetes in atherogenesis was investigated in mice with heterozygous disruption of the LDL receptor gene (LDLR1). LDLR1 mice with and without CETP expression were treated with streptozotocin (STZ) and maintained on a standard diet for one month before switching to an atherogenic diet for an additional month. STZ‐sensitive mice had ∼2.5‐fold higher glycemia and 7.5‐ to 8.0‐fold higher cholesterolemia. Factorial analysis of variance showed no significant effect of diabetes, CETP or diabetes‐CETP interaction on the size of the atherosclerotic lesions. CETP expression in non‐diabetic mice resulted in a 50% reduction in the area of the atherosclerotic lesions. Multiple regression analysis showed a positive and independent atherogenic effect of triglyceridemia in LDLR1 mice and of cholesterolemia in diabetic mice. Logistic analysis showed that elevated plasma cholesterol level significantly increased the risk of developing large lesion size (>75th percentile). In conclusion, CETP expression did not alter the lesion formation in response to diabetes, although it may be protective in the euglycemic state; the triglyceride level was an independent risk factor for LDL receptor‐deficient mice but not for CETP‐expressing mice; and elevated plasma cholesterol levels increased the risk of developing large atherosclerotic lesions, independently of CETP and diabetes.
Virucidal activities of medium‐ and long‐chain fatty alcohols, fatty acids and monoglycerides against herpes simplex virus types 1 and 2: comparison at different pH levels
Authors: HILMARSSON HILMAR , KRISTMUNDSDÓTTIR THÓRDÍS , THORMAR HALLDOR
Published: January 2005

Previous studies have shown that certain lipids and fatty alcohols have microbicidal activities against a number of pathogens. In this study, virucidal activities of fatty alcohols and lipids were tested against HSV types 1 and 2 at various concentrations, times, and pH levels. The aim was first, to determine which compounds are most virucidal against HSV and could possibly be used as active ingredients in topical drug formulations and second, to attempt to throw light on the mode of action of virucidal lipids. Good agreement was found between the activities for HSV‐1 and HSV‐2. The activity of a compound depends on the concentration and time of contact and most of the compounds are more active at pH 4.2 than at pH 7. This information may be helpful in the formulation of pharmaceutical dosage forms for treatment of herpes lesions in skin and mucosa. The difference between the polar groups of alcohols and fatty acids, i.e. hydroxyl group versus carboxyl group, and the corresponding difference in their hydrophile‐lipophile balance (HLB) may explain their different virucidal activities against HSV. However, in most cases HLB numbers cannot explain the different virucidal activities of fatty alcohols and lipids, particularly not their increased activity at low pH. It is more likely that the acidic environment makes HSV more sensitive, possibly by ionic changes in the envelope proteins.
Cellular pseudosarcomatous fibroepithelial stromal polyp of the renal pelvis
Authors: PARADA DAVID , MOREIRA OTTO , GLEDHILL TERESA , LUIGII JUAN C. , PÁEZ ALBERTO , PARDO MANUEL
Published: January 2005

Cellular pseudosarcomatous fibroepithelial stromal polyp is an underrecognized lesion described in the lower female genital tract. We here report the clinical, histological, and immunohistochemical features of a cellular pseudosarcomatous fibroepithelial stromal polyp located in the renal pelvis. A 47‐year‐old woman was referred with a 4‐month history of left flank pain and gross hematuria. Left radical nephrectomy was performed. Gross pathological examination showed irregular pedunculated polypoid masses that had developed from the renal pelvis. Histologically, spindle cells with a patternless appearance were seen. The cells were of different sizes and had discernible cytoplasmic bipolar processes. Atypical stromal cells and atypical mitoses were also found. This case represents a typical cellular pseudosarcomatous fibroepithelial stromal polyp, probably developing from a reactive hyperplastic process involving the subepithelial stroma.
Lymphoid variant of hyaline vascular Castleman's disease containing numerous mantle zone lymphocytes with clear cytoplasm
Authors: KOJIMA MASARU , NAKAMURA SHIGEO , IIJIMA MISA , MURAYAMA KAYOKO , SAKATA NORIYUKI , MASAWA NOBUHIDE
Published: January 2005

We report two unusual cases of hyaline vascular type Castleman's disease showing a pale clear cuff of mantle zone lymphocytes presenting a marginal zone distribution pattern. These cells had medium‐sized round or slightly indented nuclei and a moderate amount of clear cytoplasm. The histopathologic findings in our cases were similar to those of nodal marginal zone B‐cell lymphoma. However, immunohistochemistry demonstrated that both the mantle zone lymphocytes and the pale cuff of the lymphoid cells were CD20+, CD79a+, sIgM+, sIgD+, CD5‐, CD10‐, CD43‐, CD45RO‐, Bcl‐2+, Bcl‐6‐ and cyclin D1‐. The polytypic nature of these cells was demonstrated by immunohistochemistry and polymerase chain reaction. Reactive lymph node lesions only rarely show mantle cell hyperplasia with clear cytoplasm. This unusual mantle cell hyperplasia with clear cytoplasm associated with a hyaline vascular type of Castleman's disease should be differentiated from nodal marginal zone B‐cell lymphoma, mantle cell lymphoma and follicular lymphoma. To avoid overdiagnosis and overtreatment, it is suggested that immunophenotypic and genotypic studies might be required, and furthermore careful attention should be paid to the morphologic examination.
Training response of adolescent Kenyan town and village boys to endurance running
Authors: Larsen Henrik B. , Nolan Thomas , Borch Christian , Søndergaard Hans
Published: January 2005

To investigate the response to endurance training on physiological characteristics, 10 Nandi town boys and 14 Nandi village boys 16.5 and 16.6 years of age, respectively, from western Kenya performed 12 weeks of running training. The study was performed at altitude (∼2000 m.a.s.l. ∼595 mm Hg). Training heart rate and speed were registered during every training session throughout the entire training period. While town and village boys trained at similar heart rates (172.1 vs. 172.5 beats min−1), the training speed of the town boys was 9% lower compared with the village boys (12.4 vs. 13.6 km h−1, P<0.001). Significant increases in VO2max were observed in the town boys (from 50.3 to 55.6 mL kg−1 min−1, P<0.001) and in village boys (from 56.0 to 59.1 mL kg−1 min−1, P<0.002). Significant decreases in submaximal heart rate (from 172.4 to 160.3 beats min−1 (P<0.005)), blood lactate (from 2.7 to 1.4 mmol L−1 (P<0.005)) and ammonia concentration (from 102.0 to 71.4 μmol L−1 (P<0.01)) at 9.9 km h−1 were observed in the town boys, while similar decreases in heart rate (from 170.2 to 159.2 beats min−1 (P<0.001)), blood lactate (from 2.4 to 1.4 mmol L−1 (P<0.001)) and ammonia concentration (from 102.5 to 72.7 lmol L−1 (P<0.001)) at 10.9 km h−1 were observed in the village boys. The oxygen cost of running was decreased from 221.5 to 211.5 mL kg−1 km−1 (P<0.03) in the town boys and from 220.1 to 207.2 mL kg−1 km−1 (P<0.01) in the village boys. The 5000 m performance time of the town boys was significantly greater than that of the village boys (20.25 vs. 18.42 min (P=0.01)). It is concluded that no difference was observed in trainability with respect to VO2max, running economy, submaximal heart rate, and submaximal blood lactate and ammonia concentration between Kenyan Nandi town and village boys. The higher performance level of the village boys was likely due to a higher VO2max of these boys.
Reducing the use of diagnostic imaging in patients with suspected pulmonary embolism: Validation of a risk assessment strategy
Authors: Goergen Stacy K , Chan Thomas , De Campo John F , Wolfe Rory , Gan Eng , Wheeler Michael , McKay John
Published: January 2005

Objectives:  The aims of this study were to measure the: (i) effects of implementation of a new risk assessment strategy for patients with suspected pulmonary embolism (PE) on the use of imaging and D‐dimer assay; (ii) negative predictive value for PE of a combination of low risk and negative D‐dimer assay; and (iii) compliance of ED clinicians with the strategy.

Methods:  A non‐randomized clinical trial was conducted in the ED of a 720‐bed teaching hospital between November 2002 and August 2003. Study subjects with suspected PE were compared with 191 randomly selected historical controls. The risk assessment strategy of Kline et al. was disseminated and implemented.

Results:  The negative predictive value for PE was 99% (95% confidence interval [CI] = 97–100%) in 114 patients with low risk and negative D‐dimer. There was a 21% absolute reduction in the rate of imaging following the implementation of the risk assessment strategy (56% vs 77%, P < 0.001).

Conclusion:  Low risk combined with a negative D‐dimer result may allow exclusion of PE without imaging.
Prospective analysis of the effect of physician experience with the FAST examination in reducing the use of CT scans
Authors: Ma O John , Gaddis Gary , Steele Mark T , Cowan David , Kaltenbronn Kary
Published: January 2005

Objective:  The objective of this study was to examine the effect of ultrasound experience level on emergency physicians’ Focused Assessment with Sonography for Trauma (FAST) exam accuracy and emergency physicians’ confidence in using FAST findings to assist in managing patients with blunt trauma.

Methods:  This prospective, consecutive enrolment study evaluated adult trauma team activation blunt trauma patients. Based on the number of post‐training FAST exams carried out, 11 attending emergency physicians were grouped into A (<25 exams, n = 4), B (26–50 exams, n = 4) or C (>50 exams, n = 3). The FAST exam was carried out prior to other diagnostic studies. The emergency physicians were asked to prospectively judge their perception of the need for surgery, abdominal CT or no further tests. All study patients ultimately underwent CT, diagnostic peritoneal lavage or laparotomy. Among each physician group, the number of subsequent CT scans deemed necessary by the emergency physician after a ‘normal’ FAST was calculated and compared.

Results:  Accuracy was greatest in group C. Sixty‐nine of 80 patients in group A had a normal FAST exam; emergency physicians deemed CT necessary in 68/69 cases (99%; confidence interval [CI] 92–100%). Eighty‐two of 98 patients in group C had a normal FAST exam; emergency physicians deemed CT necessary in 19/82 cases (23%; CI 15–34%). Physicians in groups B and C were less likely to order CT after a normal FAST than group A (P < 0.001).

Conclusions:  FAST accuracy was greatest among more experienced emergency physicians. A normal FAST exam assisted more experienced emergency physicians with the perceived need to order significantly fewer CT scans than less experienced emergency physicians.
CPR before defibrillation in out‐of‐hospital cardiac arrest: A randomized trial
Authors: Jacobs Ian G , Finn Judith C , Oxer Harry F , Jelinek George A
Published: January 2005

Objective:  Current resuscitation guidelines recommend that defibrillation be undertaken as soon as possible in patients suffering a cardiac arrest where the cardiac rhythm is either ventricular fibrillation (VF) or ventricular tachycardia (VT). Evidence from animal and clinical studies suggests that outcomes may be improved if a period of cardiopulmonary resuscitation (CPR) is given prior to defibrillation. The objective of this study was to determine if 90 seconds of CPR before defibrillation improved survival.

Methods:  Patients suffering non‐paramedic witnessed VF/VT cardiac arrest were randomized to receive either 90 seconds of CPR before defibrillation (treatment) or immediate defibrillation (control). The study was carried out in Perth, Western Australia between June 2000 and June 2002. The primary endpoint was survival to hospital discharge with secondary endpoints of return of spontaneous circulation (ROSC) and survival at 1 year.

Results:  A total of 256 patients underwent randomization. Baseline characteristics including response intervals were similar in both groups. Survival to hospital discharge in the CPR first group was 4.2% (5/119) compared with 5.1% (7/137) for the immediate defibrillation group (OR 0.81; 95%CI. 0.25–2.64). No difference in those achieving ROSC was observed between the groups (OR 1.16; 95% CI 0.49–2.80).

Conclusion:  Ninety seconds of CPR before defibrillation does not improve overall survival in patients suffering VF/VT cardiac arrests. Further studies to evaluate various aspects of this treatment strategy are required as published outcomes to date are inconclusive.
Numerical Prediction of Cavitating MHD Flow of Electrically Conducting Magnetic Fluid in a Converging-Diverging Nozzle
Authors: Ishimoto Jun
Published: January 2005

The fundamental characteristics of the two-dimensional cavitating MHD flow of an electrically conducting magnetic fluid in a vertical converging-diverging nozzle under a strong nonuniform magnetic field are numerically predicted to realize the further development and high performance of a two-phase liquid-metal MHD power generation system using electrically conducting magnetic fluids. First, the governing equations of the cavitating flow of a mercury-based magnetic fluid based on the unsteady thermal nonequilibrium multifluid model are presented, and several flow characteristics are numerically calculated taking into account the effect of the strong nonuniform magnetic field. Based on the numerical results, the two-dimensional structure of the cavitating flow and cavitation inception phenomena of the mercury-based magnetic fluid through a converging-diverging nozzle are shown in detail. The numerical results demonstrate that effective two-phase magnetic driving force, fluid acceleration, and high power density are obtained by the practical use of the magnetization of the working fluid. Also clarified is the precise control of the cavitating flow of magnetic fluid that is possible by effective use of the magnetic body force that acts on cavitation bubbles.
The Onset of Tearing at Slits in Stressed Coated Plain Weave Fabrics
Authors: Godfrey T. A. , Rossettos J. N. , Bosselman S. E.
Published: January 2005

A simple micromechanical model is presented for predicting the onset of tearing at slitlike damage sites in biaxially stressed coated plain weave fabrics. The stress concentration in the first intact yarn at the slit tip is determined as a function of increasing loading, and predictions for the onset of tearing are made under the assumption that tearing initiates through the rupture of the first intact yarn at a characteristic yarn breaking load. Extensive onset of tearing experiments on various coated nylon and polyester fabrics are presented, and the model is shown to capture the onset of tearing in these fabrics quite well over a range of slit lengths.
A Superposition Framework for Discrete Dislocation Plasticity
Authors: O’Day M. P. , Curtin W. A.
Published: January 2005

A superposition technique is introduced that allows for the application of discrete dislocation (DD) plasticity to a wide range of thermomechanical problems with reduced computational effort. Problems involving regions of differing elastic and/or plastic behavior are solved by superposing the solutions to i) DD models only for those regions of the structure where dislocation phenomena are permitted subject to either zero traction or displacement at every point on the boundary and ii) an elastic (EL) (or elastic/cohesive-zone) model of the entire structure subject to all desired loading and boundary conditions. The DD subproblem is solved with standard DD machinery for an elastically homogeneous material. The EL subproblem requires only a standard elastic or elastic/cohesive-zone finite element (FE) calculation. The subproblems are coupled: the negative of the tractions developed at the boundaries of the DD subproblem are applied as body forces in the EL subproblem, while the stress field of the EL subproblem contributes a driving force to the dislocations in the DD subproblem structure. This decomposition and the generic boundary conditions of the DD subproblem permit the DD machinery to be easily applied as a “black-box” constitutive material description in an otherwise elastic FE formulation and to be used in a broader scope of applications due to the overall enhanced computational efficiency. The method is validated against prior results for crack growth along a plastic/rigid bimaterial interface. Preliminary results for crack growth along a metal/ceramic bimaterial interface are presented.
Thermal Post-Buckling of Laminated Plates Comprising Functionally Graded Materials With Temperature-Dependent Properties
Authors: Liew K. M. , Yang J. , Kitipornchai S.
Published: January 2005

This paper presents thermal buckling and post-buckling analyses for moderately thick laminated rectangular plates that contain functionally graded materials (FGMs) and subjected to a uniform temperature change. The theoretical formulation employs the first-order shear deformation theory and accounts for the effect of temperature-dependent thermoelastic properties of the constituent materials and initial geometric imperfection. The principle of minimum total potential energy, the differential quadrature method, and iterative algorithms are used to obtain critical buckling temperatures and the post-buckling temperature-deflection curves. The results are presented for both symmetrically and unsymmetrically laminated plates with ceramic/metal functionally graded layers, showing the effects of temperature-dependent properties, layup scheme, material composition, initial imperfection, geometric parameters, and boundary conditions on buckling temperature and thermal post-buckling behavior.
Implicit Multigrid Computations of Buoyant Drops Through Sinusoidal Constrictions
Authors: Muradoglu Metin , Gokaltun Seckin
Published: January 2005

Two-dimensional computations of dispersed multiphase flows involving complex geometries are presented. The numerical algorithm is based on the front-tracking method in which one set of governing equations is written for the whole computational domain and different phases are treated as a single fluid with variable material properties. The front-tracking methodology is combined with a newly developed finite volume solver based on dual time-stepping, diagonalized alternating direction implicit multigrid method. The method is first validated for a freely rising drop in a straight channel, and it is then used to compute a freely rising drop in various constricted channels. Interaction of two buoyancy-driven drops in a continuously constricted channel is also presented.
Concept and Fundamentals of Temporal-Spatial Pulse Representation for Dislocation Source Modeling
Authors: Ruichong Zhang Ray
Published: January 2005

For far-field wave-motion response to a point dynamic dislocation source, the temporal and spatial features of the source mechanism are characterized, respectively, by two factors, i.e., a source time function for dislocation growth and a combination of nine couples of impulse forces that is equivalent to the final dislocation. The mathematical representation for each of the couples, referred to as spatial couples, is a couple of impulses acting in opposing directions with an infinitesimal separation distance or, in the limit, by the derivative of the impulse with respect to the separation-distance parameter. This study proposes a temporal-spatial pulse representation for the nine couples, referred to as temporal-spatial couples, and subsequently for the dislocation source modeling. Each temporal-spatial couple consists of two impulses acting in opposite directions with both an infinitesimal separation distance and an infinitesimal time delay. By examining dynamite source modeling, this study shows that the proposed representation can intrinsically integrate the spatial and temporal features of the dislocation sources from the response point of view. This study also shows an example of a point, shear-slip seismic source modeling using traditional and proposed pulse representations for far-field wave motion. Discussion is finally provided for the implications of the proposed representation in broad applications.
Quantum Dots for Live Cells, in Vivo Imaging, and Diagnostics
Authors: Michalet X. , Pinaud F. F. , Bentolila L. A. , Tsay J. M. , Doose S. , Li J. J. , Sundaresan G. , Wu A. M. , Gambhir S. S. , Weiss S.
Published: January 2005

Research on fluorescent semiconductor nanocrystals (also known as quantum dots or qdots) has evolved over the past two decades from electronic materials science to biological applications. We review current approaches to the synthesis, solubilization, and functionalization of qdots and their applications to cell and animal biology. Recent examples of their experimental use include the observation of diffusion of individual glycine receptors in living neurons and the identification of lymph nodes in live animals by near-infrared emission during surgery. The new generations of qdots have far-reaching potential for the study of intracellular processes at the single-molecule level, high-resolution cellular imaging, long-term in vivo observation of cell trafficking, tumor targeting, and diagnostics.
Spotlight on Invisible Women
Authors: Gopinathan Asha
Published: January 2005

Pandora's Breeches
Women, Science and Power in the Enlightenment.
Patricia Fara
. Pimlico (Random House), London, 2004. 288 pp. £12.50, C$34.95. ISBN 1-8441-3082-7.

Writing for a general audience, the author explores how women contributed to the development of science in 17th- and 18th-century Europe.
Micropylar Pollen Tube Guidance by Egg Apparatus 1 of Maize
Authors: Márton Mihaela L. , Cordts Simone , Broadhvest Jean , Dresselhaus Thomas
Published: January 2005

Pollen tube guidance precedes the double fertilization of flowering plants. Here, we report the identification of a small maize protein of 94 amino acids involved in short-range signaling required for pollen tube attraction by the female gametophyte.
ZmEA1
is exclusively expressed in the egg apparatus, consisting of the egg cell and two synergids. Chimeric ZmEA1 fused to green fluorescent protein (ZmEA1:GFP) was first visible within the filiform apparatus and later was localized to nucellar cell walls below the micropylar opening of the ovule. Transgenic down-regulation of the
ZmEA1
gene led to ovule sterility caused by loss of close-range pollen tube guidance to the micropyle.
A Molecular Phylogeny for Bats Illuminates Biogeography and the Fossil Record
Authors: Teeling Emma C. , Springer Mark S. , Madsen Ole , Bates Paul , O'Brien Stephen J. , Murphy William J.
Published: January 2005

Bats make up more than 20% of extant mammals, yet their evolutionary history is largely unknown because of a limited fossil record and conflicting or incomplete phylogenies. Here, we present a highly resolved molecular phylogeny for all extant bat families. Our results support the hypothesis that megabats are nested among four major microbat lineages, which originated in the early Eocene [52 to 50 million years ago (Mya)], coincident with a significant global rise in temperature, increase in plant diversity and abundance, and the zenith of Tertiary insect diversity. Our data suggest that bats originated in Laurasia, possibly in North America, and that three of the major microbat lineages are Laurasian in origin, whereas the fourth is Gondwanan. Combining principles of ghost lineage analysis with molecular divergence dates, we estimate that the bat fossil record underestimates (unrepresented basal branch length, UBBL) first occurrences by, on average, 73% and that the sum of missing fossil history is 61%.
Restoration of Tolerance in Lupus by Targeted Inhibitory Receptor Expression
Authors: McGaha Tracy L. , Sorrentino Brian , Ravetch Jeffrey V.
Published: January 2005

Lupus, a multigenic autoimmune condition in which a breakdown of tolerance results in the development of autoantibodies, leads to a variety of pathologic outcomes. Despite the heterogeneity of factors influencing disease susceptibility, we demonstrate that the partial restoration of inhibitory Fc receptor (FcgRIIB) levels on B cells in lupus-prone mouse strains is sufficient to restore tolerance and prevent autoimmunity. FcgRIIB regulates a common B cell checkpoint in genetically diverse lupus-prone mouse strains, and modest changes in its expression can result in either tolerance or autoimmunity. Therefore, increasing FcγRIIB levels on B cells may be an effective way to treat autoimmune diseases.
Marine Fish Egg Hydration Is Aquaporin-Mediated
Authors: Fabra Mercedes , Raldúa Demetrio , Power Deborah M. , Deen Peter M. T. , Cerdà Joan
Published: January 2005

The positive buoyancy of marine fish eggs in sea water, allowed by hydration of the oocyte, is critical for their survival and dispersion in the ocean. We isolated an aquaporin, SaAQP1o, that belongs to a unique subfamily of aquaporin-1—like channels specifically evolved in teleosts and mainly expressed in the ovary. We further show that hormone-induced fish oocyte hydration is a highly controlled process based on the interplay between protein hydrolysis and the translocation of SaAQP1o to the plasma membrane, indicating a specialized physiological role for this aquaporin.
Ammonia Synthesis from First-Principles Calculations
Authors: Honkala K. , Hellman A. , Remediakis I. N. , Logadottir A. , Carlsson A. , Dahl S. , Christensen C. H. , Nørskov J. K.
Published: January 2005

The rate of ammonia synthesis over a nanoparticle ruthenium catalyst can be calculated directly on the basis of a quantum chemical treatment of the problem using density functional theory. We compared the results to measured rates over a ruthenium catalyst supported on magnesium aluminum spinel. When the size distribution of ruthenium particles measured by transmission electron microscopy was used as the link between the catalyst material and the theoretical treatment, the calculated rate was within a factor of 3 to 20 of the experimental rate. This offers hope for computer-based methods in the search for catalysts.
Prediction of Hydrogen Flux Through Sulfur-Tolerant Binary Alloy Membranes
Authors: Kamakoti Preeti , Morreale Bryan D. , Ciocco Michael V. , Howard Bret H. , Killmeyer Richard P. , Cugini Anthony V. , Sholl David S.
Published: January 2005

Metal membranes play a vital role in hydrogen purification. Defect-free membranes can exhibit effectively infinite selectivity but must also provide high fluxes, resistance to poisoning, long operational lifetimes, and low cost. Alloying offers one route to improve on membranes based on pure metals such as palladium. We show how ab initio calculations and coarse-grained modeling can accurately predict hydrogen fluxes through binary alloy membranes as functions of alloy composition, temperature, and pressure. Our approach, which requires no experimental input apart from knowledge of bulk crystal structures, is demonstrated for palladium-copper alloys, which show nontrivial behavior due to the existence of face-centered cubic and body-centered cubic crystal structures and have the potential to resist sulfur poisoning. The accuracy of our approach is examined by a comparison with extensive experiments using thick foils at elevated temperatures. Our experiments also demonstrate the ability of these membranes to resist poisoning by hydrogen sulfide.
Learning from 100 Numbers
Authors: Strang Gilbert
Published: January 2005

The SIAM 100-Digit Challenge
A Study in High-Accuracy Numerical Computing.
By Folkmar Bornemann, Dirk Laurie, Stan Wagon, and Jörg Waldvogel
. SIAM Press, Philadelphia, 2004. 318 pp. $57. ISBN 0-89871-561-X.

The authors discuss a range of clever algorithms and mathematical machinery for efficient computation that they used to solve the 10 problems posed for a 2002 contest.
Complete Genome Sequence of the Grouper Iridovirus and Comparison of Genomic Organization with Those of Other Iridoviruses
Authors: Tsai Chih-Tung , Ting Jing-Wen , Wu Ming-Hsien , Wu Ming-Feng , Guo Ing-Cherng , Chang Chi-Yao
Published: January 2005

The complete DNA sequence of grouper iridovirus (GIV) was determined using a whole-genome shotgun approach on virion DNA. The circular form genome was 139,793 bp in length with a 49% G+C content. It contained 120 predicted open reading frames (ORFs) with coding capacities ranging from 62 to 1,268 amino acids. A total of 21% (25 of 120) of GIV ORFs are conserved in the other five sequenced iridovirus genomes, including DNA replication, transcription, nucleotide metabolism, protein modification, viral structure, and virus-host interaction genes. The whole-genome nucleotide pairwise comparison showed that GIV virus was partially colinear with counterparts of previously sequenced ranaviruses (ATV and TFV). Besides, sequence analysis revealed that GIV possesses several unique features which are different from those of other complete sequenced iridovirus genomes: (i) GIV is the first ranavirus-like virus which has been sequenced completely and which infects fish other than amphibians, (ii) GIV is the only vertebrate iridovirus without CpG sequence methylation and lacking DNA methyltransferase, (iii) GIV contains a purine nucleoside phosphorylase gene which is not found in other iridoviruses or in any other viruses, (iv) GIV contains 17 sets of repeat sequence, with basic unit sizes ranging from 9 to 63 bp, dispersed throughout the whole genome. These distinctive features of GIV further extend our understanding of molecular events taking place between ranavirus and its hosts and the iridovirus evolution.
Role of CCL11 in Eosinophilic Lung Disease during Respiratory Syncytial Virus Infection
Authors: Matthews Stephen P. , Tregoning John S. , Coyle Anthony J. , Hussell Tracy , Openshaw Peter J. M.
Published: January 2005

Respiratory syncytial virus (RSV) is a major viral pathogen of infants and the elderly. Significant morbidity is caused by an overexuberant mixed lung cell infiltrate, which is thought to be driven by chemokines. One of the main chemotactic mediators responsible for the movement of eosinophils is CCL11 (eotaxin). Using a mouse model of eosinophilic bronchiolitis induced by RSV, we show here that treatment in vivo with a blocking antibody to CCL11 greatly reduces lung eosinophilia and disease severity. In addition, anti-CCL11 caused a striking inhibition of CD4-T-cell influx and shifted cytokine production away from interleukin-5 without reducing the resistance to viral replication. These results suggest that in addition to influencing eosinophil diapedesis and survival, anti-CCL11 has an action on T cells. These studies strengthen the case for anti-CCL11 treatment of Th2-driven diseases.
Caffeine Inhibits Human Immunodeficiency Virus Type 1 Transduction of Nondividing Cells
Authors: Daniel René , Marusich Elena , Argyris Elias , Zhao Richard Y. , Skalka Anna Marie , Pomerantz Roger J.
Published: January 2005

Caffeine is an efficient inhibitor of DNA repair and DNA damage-activated checkpoints. We have shown recently that caffeine inhibits retroviral transduction of dividing cells, most likely by blocking postintegration repair. This effect may be mediated at least in part by a cellular target of caffeine, the ataxia telangiectasia-mutated and Rad3-related (ATR) kinase. In this study, we present evidence that caffeine also inhibits efficient transduction of nondividing cells. We observed reduced transduction in caffeine-treated growth-arrested cells as well as caffeine-treated terminally differentiated human neurons and macrophages. Furthermore, this deficiency was observed with a human immunodeficiency virus type 1 (HIV-1) vector lacking Vpr, indicating that the effect is independent of the presence of this viral protein in the infecting virion. Finally, we show that HIV-1 transduction of nocodazole-arrested cells is reduced in cells that express an ATR dominant-negative protein (kinase-dead ATR [ATRkd]) and that the residual transduction of ATRkd-expressing cells is relatively resistant to caffeine. Taken together, these data suggest that the effect(s) of caffeine on HIV-1 transduction is mediated at least partly by the inhibition of the ATR pathway but is not dependent on the caffeine-mediated inhibition of cell cycle checkpoints.
Identification of a Movement Protein of Rice Yellow Stunt Rhabdovirus
Authors: Huang Yan-Wei , Geng Yun-Feng , Ying Xiao-Bao , Chen Xiao-Ying , Fang Rong-Xiang
Published: January 2005

Rice yellow stunt rhabdovirus(RYSV) encodes seven genes in its negative-sense RNA genome in the order 3′-N-P-3-M-G-6-L-5′. The existence of gene 3 in the RYSV genome and an analogous gene(s) of other plant rhabdoviruses positioned between the P and M genes constitutes a unique feature for plant rhabdoviruses that is distinct from animal-infecting rhabdoviruses in which the P and M genes are directly linked. However, little is known about the function of these extra plant rhabdovirus genes. Here we provide evidence showing that the protein product encoded by gene 3 of RYSV, P3, possesses several properties related to a viral cell-to-cell movement protein (MP). Analyses of the primary and secondary protein structures suggested that RYSV P3 is a member of the “30K” superfamily of viral MPs. Biolistic bombardment transcomplementation experiments demonstrated that RYSV P3 can support the intercellular movement of a movement-deficient potexvirus mutant inNicotiana benthamianaleaves. In addition, Northwestern blot analysis indicated that the RYSV P3 protein can bind single-stranded RNA in vitro, a common feature of viral MPs. Finally, glutathioneS- transferase pull-down assays revealed a specific interaction between the RYSV P3 protein and the N protein which is a main component of the ribonucleocapsid, a subviral structure believed to be involved in the intercellular movement of plant rhabdoviruses. Together, these data suggest that RYSV P3 is likely a MP of RYSV, thus representing the first example of characterized MPs for plant rhabdoviruses.