bluuebunny/crossref_metadata_2025 huggingface dataset:
Infiltration of Foxp3‐ and Toll‐like Receptor‐4–positive Cells in the Intestines of Children With Food Allergy
Authors: Westerholm‐Ormio Mia , Vaarala Outi , Tiittanen Minna , Savilahti Erkki
Published: March 2010

Objectives:

Regulatory T (Treg) cells together with intestinal microflora play a central role in controlling allergic inflammation. We examined the markers related to Treg cells, and bacterial signaling, such as Toll‐like receptors (TLR)‐2 and ‐4, in the duodenal mucosa of patients with food allergy (FA).

Patients and Methods:

Small intestinal samples were collected from patients with FA on a normal or an elimination diet, from healthy controls and patients with untreated celiac disease. Single and double immunohistochemistry were used to enumerate the densities of Foxp3‐positive cells and TLR2‐ and TLR4‐positive cells in the mucosa and evaluate the colocalization of Foxp3 expression in CD4+, CD25+, and CTLA‐4+ cells. The mRNA expression of CD25, Foxp3, TLR2, and TLR4 was measured by reverse transcriptase‐polymerase chain reaction.

Results:

The densities of Foxp3+ and TLR4+ cells were significantly increased in patients with untreated FA compared with healthy controls (P = 0.003, P = 0.033), and the Foxp3+ cells were higher in untreated than in treated allergic patients (P < 0.001). The immense majority of Foxp3+ cells were CD4+ (median 100%), CTLA‐4+ (100%), or CD25+ (81%). The ratio of Foxp3 mRNA to Foxp3+ cells was decreased in patients with FA and in patients with celiac disease compared with controls (P = 0.036, P = 0.035).

Conclusions:

Foxp3+ cells are increased in the duodenum of patients with untreated FA, but these cells are not able to suppress the harmful immune response, indicated by the low expression of Foxp3 transcripts. The increase of TLR4+ cells and their correlation with TCRγδ+ intraepithelial lymphocytes suggest a role for the innate immunity and intestinal microbiota in FA.
Partially Hydrolyzed 100% Whey Protein Infant Formula and Reduced Risk of Atopic Dermatitis: A Meta‐analysis
Authors: Alexander Dominik D , Cabana Michael D
Published: March 2010

Objective:

A reduced risk of atopic dermatitis (AD) among healthy infants who received 100% whey protein partially hydrolyzed formula (PHF‐W) compared with intact protein cow's milk formula (CMF), has been reported in several studies. To validate these observations and estimate the magnitude of this potential association with greater statistical precision, we conducted a meta‐analysis of clinical trial and intervention studies.

Materials and Methods:

A total of 18 articles representing 12 independent study populations met our inclusion criteria.

Results:

A statistically significant 44% (summary relative risk estimate [SRRE] = 0.56, 95% confidence interval 0.40–0.77) reduced risk of atopic manifestations, which included AD, was found among infants receiving PHF‐W compared with infants receiving CMF. In a subanalysis of 4 studies that reported results specifically for AD and that were considered of superior methodological quality, the incidence of AD was reduced by 55% (SRRE = 0.45, 95% confidence interval 0.30–0.70).

Conclusions:

Regardless of study design, infant population, follow‐up time, or study location, individual study findings were consistent because a reduced incidence of AD was reported in all of the reviewed studies. Exclusive breast‐feeding should be encouraged as the standard for infant nutrition in the first months of life. For infants who are not exclusively breast‐fed, feeding with PHF‐W instead of CMF reduces the risk of AD in infants, particularly in infants with a family history of allergy.
Three cases of Arcanobacterium pyogenes-associated soft tissue infection
Authors: Kavitha Kannaiyan , Latha R. , Udayashankar C. , Jayanthi K. , Oudeacoumar P.
Published: March 2010

Arcanobacterium pyogenes is an established but often unrecognized human pathogen. A. pyogenes may also be misidentified as Arcanobacterium haemolyticum, which gives remarkably similar results in conventional biochemical tests. In this study, we have reported three cases of wound infections associated with A. pyogenes and also on the bacteriological characteristics which are relevant for identification of these isolates. The negative reverse CAMP test, the ability to produce acid from xylose and to hydrolyse gelatin and the positive β-glucuronidase test clearly differentiated A. pyogenes from other closely related species. All three isolates were uniformly susceptible to penicillin, ampicillin, amoxicillin–clavulanic acid, ceftriaxone and gentamicin, variably susceptible to tetracycline and erythromycin and uniformly resistant to cotrimoxazole. Only a few confirmed cases have been reported throughout the world and therefore the diagnostic evaluation of this organism is emphasized.
Silicone colonization by non-Candida albicans Candida species in the presence of urine
Authors: Silva Sónia , Negri Melyssa , Henriques Mariana , Oliveira Rosário , Williams David , Azeredo Joana
Published: March 2010

Urinary tract infections (UTIs) are the most common nosocomial infections and 80 % are related to the use of urinary catheters. Furthermore,Candidaspecies are responsible for around 15 % of UTIs and an increasing involvement of non-Candida albicans Candida(NCAC) species (e.g.Candida glabrata,Candida tropicalisandCandida parapsilosis) has been recognized. Given the fact that silicone is frequently used in the manufacture of urinary catheters, the aim of this work was to compare both the adhesion and biofilm formation on silicone of different urinary clinical isolates of NCAC species (i.e.C. glabrata,C. tropicalisandC. parapsilosis) in the presence of urine. Several clinical isolates of NCAC species recovered from patients with UTIs, together with reference strains of each species, were examined. Adhesion and biofilm formation were performed in artificial urine and the biofilm biomass was assessed by crystal violet staining. Hydrophobicity and surface charge of cells was determined by measuring contact angles and zeta potential, respectively. The number of viable cells in biofilms was determined by enumeration of c.f.u. after appropriate culture. The biofilm structure was also examined by confocal laser scanning microscopy (CLSM). The results showed that all isolates adhered to silicone in a species- and strain-dependent manner withC. parapsilosisshowing the lowest andC. glabratathe highest levels of adhesion. However, these differences in adhesion abilities cannot be correlated with surface properties since all strains examined were hydrophilic and exhibited a similar zeta potential. Despite a higher number of cultivable cells being recovered after 72 h of incubation, stronger biofilm formation was not observed and CLSM showed an absence of extracellular polymeric material for all isolates examined. In summary, this work demonstrated that all tested NCAC species were able to adhere to and survive on silicone in the presence of urine. Furthermore,C. glabratastrains presented higher colonization abilities thanC. tropicalisandC. parapsilosisstrains, a fact that might explain the larger role ofC. glabratacolonization and disseminated infections in hospitalized and catheterized patients.
Ribulose-1,5-bisphosphate carboxylase/oxygenase genes as a functional marker for chemolithoautotrophic halophilic sulfur-oxidizing bacteria in hypersaline habitats
Authors: Tourova Tatjana P. , Kovaleva Olga L. , Sorokin Dimitry Yu. , Muyzer Gerard
Published: March 2010

The presence and diversity of the cbb genes encoding the large subunit of ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO) (a key enzyme of the Calvin–Benson cycle of autotrophic CO2 assimilation) were investigated in pure cultures of seven genera of halophilic chemolithoautotrophic sulfur-oxidizing bacteria (SOB) and in sediments from a hypersaline lake in which such bacteria have been recently discovered. All of the halophilic SOB strains (with the exception of Thiohalomonas nitratireducens) possessed the cbbL gene encoding RuBisCO form I, while the cbbM gene encoding RuBisCO form II was detected only in some of the pure cultures. The general topologies of the CbbL/CbbM trees and the 16S rRNA gene tree were different, but both markers showed that the halophilic SOB genera formed independent lineages in the Gammaproteobacteria. In some cases, such as with several strains of the genus Thiohalospira and with Thioalkalibacter halophilus, the cbbL clustering was incongruent with the positions of these strains on the ribosomal tree. In the cbbM tree, the clustering of Thiohalospira and Thiohalorhabdus strains was incongruent with their branching in both cbbL and 16S rRNA gene trees. cbbL and cbbM genes related to those found in the analysed halophilic SOB were also detected in a sediment from a hypersaline lake in Kulunda Steppe (Russia). Most of the cbbL and cbbM genes belonged to members of the genus Thiohalorhabdus. In the cbbL clone library, sequences related to those of Halothiobacillus and Thiohalospira were detected as minor components. Some of the environmental cbbM sequences belonged to as yet unknown phylotypes, representing deep lineages of halophilic autotrophs.
The high-adhesive properties of the FimH adhesin of Salmonella enterica serovar Enteritidis are determined by a single F118S substitution
Authors: Grzymajło Krzysztof , Kuźmińska-Bajor Marta , Jaworski Jakub , Dobryszycki Piotr , Ugorski Maciej
Published: March 2010

The binding properties of low- and high-adhesive forms of FimH adhesins from Salmonella enterica serovars Enteritidis and Typhimurium (S. Enteritidis and S. Typhimurium) were studied using chimeric proteins containing an additional peptide that represents an N-terminal extension of the FimF protein. This modification, by taking advantage of a donor strand exchange mechanism, closes the hydrophobic groove in the fimbrial domain of the FimH adhesin. Such self-complemented adhesins (scFimH) did not form aggregates and were more stable (resistant to proteolytic cleavage) than native FimH. High-adhesive variants of scFimH proteins, with alanine at position 61 and serine at position 118, were obtained by site-directed mutagenesis of fimH genes from low-adhesive variants of S. Enteritidis and S. Typhimurium, with glycine at position 61 and phenylalanine at position 118. Direct kinetic analysis using surface plasmon resonance (SPR) and glycoproteins carrying high-mannose carbohydrate chains (RNase B, horseradish peroxidase and mannan-BSA) revealed the existence of high- and low-adhesive allelic variants, not only in S. Typhimurium but also in S. Enteritidis. Using two additional mutants of low-adhesive FimH protein from S. Enteritidis (Gly61Ala and Phe118Ser), SPR analysis pointed to Ser118 as the major determinant of the high-adhesive phenotype of type 1 fimbriae from S. Enteritidis. These studies demonstrated for the first time that the functional differences observed with whole fimbriated bacteria could be reproduced at the level of purified adhesin. They strongly suggest that the adhesive properties of type 1 fimbriae are determined only by structural differences in the FimH proteins and are not influenced by the fimbrial shaft on which the adhesin is located.
TheArabidopsisFloral Homeotic Proteins APETALA3 and PISTILLATA Negatively Regulate theBANQUOGenes Implicated in Light Signaling
Authors: Mara Chloe D. , Huang Tengbo , Irish Vivian F.
Published: March 2010

The Arabidopsis thaliana MADS box transcription factors APETALA3 (AP3) and PISTILLATA (PI) heterodimerize and are required to specify petal identity, yet many details of how this regulatory process is effected are unclear. We have identified three related genes, BHLH136/BANQUO1 (BNQ1), BHLH134/BANQUO2 (BNQ2), and BHLH161/BANQUO3 (BNQ3), as being directly and negatively regulated by AP3 and PI in petals. BNQ1, BNQ2, and BNQ3 encode products belonging to a family of atypical non-DNA binding basic helix-loop-helix (bHLH) proteins that heterodimerize with and negatively regulate bHLH transcription factors. We show that bnq3 mutants have pale-green sepals and carpels and decreased chlorophyll levels, suggesting that BNQ3 has a role in regulating light responses. The ap3 bnq3 double mutant displays pale second-whorl organs, supporting the hypothesis that BNQ3 is downstream of AP3. Consistent with a role in light response, we show that the BNQ gene products regulate the function of HFR1 (for LONG HYPOCOTYL IN FAR-RED1), which encodes a bHLH protein that regulates photomorphogenesis through modulating phytochrome and cryptochrome signaling. The BNQ genes also are required for appropriate regulation of flowering time. Our results suggest that petal identity is specified in part through downregulation of BNQ-dependent photomorphogenic and developmental signaling pathways.
Promoters of the Barley Germin-LikeGER4Gene Cluster Enable Strong Transgene Expression in Response to Pathogen Attack
Authors: Himmelbach Axel , Liu Luo , Zierold Uwe , Altschmied Lothar , Maucher Helmut , Beier Franziska , Müller Doreen , Hensel Götz , Heise Andreas , Schützendübel Andres , Kumlehn Jochen , Schweizer Patrick
Published: March 2010

Immunity of plants triggered by pathogen-associated molecular patterns (PAMPs) is based on the execution of an evolutionarily conserved defense response that includes the accumulation of pathogenesis-related (PR) proteins as well as multiple other defenses. The most abundant PR transcript of barley (Hordeum vulgare) leaf epidermis attacked by the powdery mildew fungus Blumeria graminis f. sp hordei encodes the germin-like protein GER4, which has superoxide dismutase activity and functions in PAMP-triggered immunity. Here, we show that barley GER4 is encoded by a dense cluster of tandemly duplicated genes (GER4a-h) that underwent several cycles of duplication. The genomic organization of the GER4 locus also provides evidence for repeated gene birth and death cycles. The GER4 promoters contain multiple WRKY factor binding sites (W-boxes) preferentially located in promoter fragments that were exchanged between subfamily members by gene conversion. Mutational analysis of TATA-box proximal W-boxes used GER4c promoter-β-glucuronidase fusions to reveal their enhancing effects and functional redundancy on pathogen-induced promoter activity. The data suggest enhanced transcript dosage as an evolutionary driving force for the local expansion and functional redundancy of the GER4 locus. In addition, the GER4c promoter provides a tool to study signal transduction of PAMP-triggered immunity and to engineer strictly localized and pathogen-regulated disease resistance in transgenic cereal crops.
Apomictic and Sexual Ovules ofBoecheraDisplay Heterochronic Global Gene Expression Patterns
Authors: Sharbel Timothy F. , Voigt Marie-Luise , Corral José M. , Galla Giulio , Kumlehn Jochen , Klukas Christian , Schreiber Falk , Vogel Heiko , Rotter Björn
Published: March 2010

We have compared the transcriptomic profiles of microdissected live ovules at four developmental stages between a diploid sexual and diploid apomictic Boechera. We sequenced >2 million SuperSAGE tags and identified (1) heterochronic tags (n = 595) that demonstrated significantly different patterns of expression between sexual and apomictic ovules across all developmental stages, (2) stage-specific tags (n = 577) that were found in a single developmental stage and differentially expressed between the sexual and apomictic ovules, and (3) sex-specific (n = 237) and apomixis-specific (n = 1106) tags that were found in all four developmental stages but in only one reproductive mode. Most heterochronic and stage-specific tags were significantly downregulated during early apomictic ovule development, and 110 were associated with reproduction. By contrast, most late stage-specific tags were upregulated in the apomictic ovules, likely the result of increased gene copy number in apomictic (hexaploid) versus sexual (triploid) endosperm or of parthenogenesis. Finally, we show that apomixis-specific gene expression is characterized by a significant overrepresentation of transcription factor activity. We hypothesize that apomeiosis is associated with global downregulation at the megaspore mother cell stage. As the diploid apomict analyzed here is an ancient hybrid, these data are consistent with the postulated link between hybridization and asexuality and provide a hypothesis for multiple evolutionary origins of apomixis in the genus Boechera.
PROBLEM DEPARTMENT
Authors: Jamison G. H.
Published: March 2010

This department aims to provide problems of varying degrees of difficulty which will interest anyone engaged in the study of mathematics.

All readers are invited to propose problems and to solve problems here proposed, Drawings to illustrate the problems should be well done in India ink. Problems and solutions will be credited to their authors. Each solution, or proposed problem, sent to the Editor should have the author's name introducing the problem or solution as on the following pages.

The Editor of the department desires to serve its readers by making it interesting and helpful to them. Address suggestions and problems to G. H. Jamison, State Teachers College, Kirksville, Missouri.
REFLECTION OF LIGHT
Authors: Cebelius Arthur E.
Published: March 2010

[This article is the introductory portion of a paper on reflection prepared by Mr. Cebelius for presentation before a class in “Physical Science for the Junior High School” of which he is a member. Mr. Cebelius is a Senior at the Teachers College of Connecticut. The object of this article is to illustrate types of laboratory activity pertinent to the subject being discussed. O. E. Underbill, Instructor in science.]
Software Reviews
Authors: McGrath Diane
Published: March 2010

Exploring Chaos

Neuroanatomy Foundations
BOOK REVIEWS
Authors: Abdi S. Wali
Published: March 2010

Book reviewed in this article:

The Geometric Supposer: What Is It A Case Of?, Edited by Judah L. Schwartz, Michal Yerushalmy, and Beth Wilson.

Profiles of Ecologists: Results of a Survey of the Membership of the Ecological Society of America, Marjorie M. Holland, David M. Lawrence, Deborah J. Morrin, Carol Hunsaker, David Ianoye, Anthony Janetos, H. Ronald Pulliam, William Robertson, and John Wilson.

Garbage, Maria Fleming.
Developing Interdisciplinary Units: Strategies and Examples
Authors: McDonald Jacqueline , Czerniak Charlene
Published: March 2010

The authors use a common theme of SHARKS to illustrate the process of developing an interdisciplinary unit for middle school instruction. A model is presented for teams to use in developing integrated curriculum. Focusing on a central theme or topic, a web of disciplines and key concepts is developed. As activities evolve, a concept map is created to illustrate the relationships and integration of ideas and activities.
The Virginia State Systemic Initiative: A Brief Overview of the Lead Teacher Component and a Description of the Evolving Mathematics & Science Integration Outcomes
Authors: Underhill Robert G. , Abdi S. Wali , Peters P. Frank
Published: March 2010

This article describes the Lead Teacher Component of the NSF‐funded State Systemic Initiative, Virginia's Quality Education in Science and Technology (V‐QUEST). Part of V‐QUEST focuses on the integration of mathematics and science in elementary and middle schools. Some recent research findings and recommendations which informed the planning and decisions are cited. The article describes the guiding principles, objectives, strategies, and agencies involved in the project. An outline of how the integration of mathematics and science elements were developed is provided and some preliminary outcomes are catalogued. An important feature of the systemic project is the manner through which it includes a wide range of individuals and organizations concerned with education in all the planning and implementation phases.
Data Collection and Elementary School Mathematics
Authors: Evered Lisa J.
Published: March 2010

The curriculum standards of the National Council of Teachers of Mathematics advocate the inclusion of data collection activities throughout the middle school. This paper presents activities that implement these recommendations. Activities include data collection in the home, school and community and encourage students to summarize, interpret, and draw inferences from the data they collect individually and in cooperative groups. Four types of data collection activities are presented ‐ observations, surveys, experiments and sampling. Every activity requires minimal planning/preparation by the teacher yet involves students in a variety of roles. Further, each activity can be adapted to different classroom settings.
Gender, Prior Academic Performance and Beliefs as Predictors of Attitudes Toward Biology Laboratory Experiences
Authors: Weinburgh Molly H. , Englehard George
Published: March 2010

The purpose of this study was to investigate the relationships between gender, prior academic performance, beliefs and student attitudes toward biology laboratory experiences. The sample consisted of 294 students from 10th, 11th and 12th grades enrolled in a Catholic high school in a major metropolitan area in the Southeast. Two 11‐item scales were created; one to measure student attitudes toward biology laboratory experiences, and the other to measure student beliefs about the benefits of biology laboratory. A three‐way analysis of variance (gender × prior academic performance × beliefs) was conducted with the attitudes toward biology used as the dependent variable. Gender had a significant effect on attitudes, with females reporting more positive attitudes toward biology laboratory than males. Prior academic experience was also a significant predictor of attitudes; students who received lower GPAs in previous science courses reported more positive attitudes toward biology laboratory than students with higher GPAs. Based on previous research this finding was surprising; however, it appears that lower achieving students may perceive that there is a higher benefit from “hands on” laboratory experiences than high achieving students. The data also indicated that beliefs had the strongest correlations with attitudes; students who believed laboratory experiences were beneficial had more positive attitudes. The implications for research, theory and practice are also presented.
Mathematics in Context: Measurement, Packaging and Caring for Our Environment
Authors: Anderson Ann
Published: March 2010

The purpose of this article is to present illustrative examples which will help teachers and teacher educators combine mathematics and science through the activities which involve higher order thinking and worthwhile tasks. Packaging provides an important and meaningful context for exploring important mathematics and an important environmental issue.
Students Explaining Solutions in Student‐Directed Groups: Cooperative Learning and Reform in Mathematics Education
Authors: Ross John A.
Published: March 2010

Cooperative learning experiences can contribute to mathematics education reform by stimulating student communication. Sixth grade student conversations were recorded on four occasions over a four month period when they were working in cooperative groups. The results indicated that routine compliance with the requirement to “explain” superseded authentic dialogues about mathematical ideas. Student conversations were influenced by the model of explanation exchanges emerging from the teacher's visits to groups. Teacher influence was mediated by students' past experiences. The findings suggest that teachers implementing reform should help students develop criteria for judging mathematical arguments and confront student conceptions directly to deepen debates.
Tech Prep Academics: Using Real Life Connections to Develop Scientific and Mathematical Literacy
Authors: Mitchell Charles E. , Miller L. Diane
Published: March 2010

Based upon the recommendations of professional organizations in science and mathematics education, children at K‐6 levels need to be exposed to activities involving scientific methodology, the discovery of new knowledge and the integration of science and mathematics curricula. This study describes several distinct kinds of problem solving investigations identified from real life situations which can be adapted in intellectually honest ways for selected levels of the elementary school curriculum. The activities lend themselves to interactions with businesses and industries in the children's community and involve the children in a variety of non‐traditional instructional activities such as oral presentations, small group collaborative efforts, and written reports. Finally, the investigations promote the integration of science and mathematics curricula and suggest the role curricula can play in the lives of children.
Connections in Proportional Reasoning: Levers, Arithmetic Means, Mixtures, Batting Averages, and Speeds
Authors: Flores Alfinio
Published: March 2010

The lever is used to give an alternate physical representation of, and as a means to connect, situations that involve weighted averages and inverse proportionality, such as arithmetic means, mixtures, batting averages, and speeds. Geometric representations of the situations are also provided as another way to make connections.
Mathematics Assessment: Practices and Reporting Methods
Authors: Schmidt Mary Ellen , Brosnan Patricia A.
Published: March 2010

The curriculum, teaching, and assessment Standards of the National Council of Teachers of Mathematics advocate the use of various assessment techniques in mathematics, K‐12. Practitioners from 35 school districts in two regions of a midwestern state completed a questionnaire and reported information about their assessment practices, reporting methods, and other issues that affect change in mathematics. The results of the survey suggest that current reporting practices are limiting the use of alternative classroom assessment practices. Delays in the use of alternative mathematics assessment practice can probably be expected until the reporting systems used in school districts become consistent with the assessment systems and teachers participate in ongoing professional development programs to learn more about alternative assessment practices.
Predictors of Success in a District Science Fair Competition: An Exploratory Study
Authors: Czerniak Charlene M.
Published: March 2010

This exploratory study examined relationships among success in a regional science fair and self‐concept, parental influences, motivation, anxiety, and selected demographic variables. The sample included 142 students in grades 7–12 who were enrolled in a district science day in Ohio. Confidence levels and parental influences were measured using scales developed by Campbell (1991). Motivation was measured with items asking who or what influenced students to enter the district science fair and whether they intended to attend college and major in a science‐related field. The State‐Trait Anxiety Indicator (STAI) (Spielberger, 1983) was used to measure anxiety. Success in the district science day was measured by the rating given by a pair of judges for the science fair project. Demographic variables examined were GPA, participation in a gifted/talented class, participation in a scientific research course, gender, ethnicity, and parents' level of education. Descriptive and discriminant statistical techniques were used to analyze the data. A discriminant function analysis determined one significant function which predicted rating in the science fair. This function, accounting for 77% of the variance, included five coefficients—parental help, parental pressure, science self concept, the science fair project counted as part of a science course grade, and the judges' rating on the science fair project determined the course grade. Implications are discussed for classroom teachers who enroll students in science fairs.
The Zoo Connection: A Cooperative Project Between Formal and Informal Educational Institutions
Authors: Barman Charles R. , Lessow Denise , Lessow Barry , Shedd Jill D.
Published: March 2010

This project was a cooperative effort between university faculty, elementary school teachers, and members of the Education Department at the Indianapolis Zoo. The purpose of this project was to develop, evaluate, and disseminate a set of fourteen K‐6 science lessons that could be used in conjunction with field trips to the zoo. These lessons, titled The Zoo Connection, follow the Learning Cycle teaching model. In addition to following the model, the development of the lessons was based on the premise that teachers should focus on a specific science concept or set of related concepts when visiting a zoo. Workshop sessions were conducted to introduce teachers to the materials and to provide them with strategies for implementing the materials in their science instruction. An evaluation was conducted for each workshop session to determine teachers' perceptions of the materials and to determine whether they felt prepared to use them with their students. The materials were also field‐tested in several elementary schools to assess their effectiveness for presenting science concepts to elementary school children. Results indicate that teachers felt the workshops adequately prepared them to use the materials and that the materials were effective for presenting science concepts.
Student Performance on Asking Questions, Identifying Variables, and Formulating Hypotheses
Authors: Germann Paul J. , Aram Roberta , Odom A. Louis , Burke Gerald
Published: March 2010

The purpose of this study was to extend attempts to develop a research framework for encoding and analyzing students' responses to the tasks of asking questions, identifying variables, and formulating hypotheses, and to use the research framework to analyze and classify the responses of seventh grade students. A performance‐based assessment instrument was used. The topic was heat and temperature. The responses of 364 seventh grade students were used to develop a framework for evaluating student written responses which allows researchers to classify student responses according to their general completeness and usefulness, and according to the manner in which responses were incomplete or not useful. Interrater reliability was 82%. Seventh grade students who reportedly have had instruction in the science processes did not perform well on this performance‐based assessment.
Gender Differences in Risk‐Taking Behavior and their Relationship to SAT‐Mathematics Performance
Authors: Ramos Ismael , Lambating Julita
Published: March 2010

This study focused on the relationship of an individual's risk‐taking behavior and his/her performance on the mathematics section of the Scholastic Aptitude Test (SAT‐M). Previous research in this area has found that on multiple choice tests, calculated guessing (risk‐taking) plays a role in the score one obtains. Risk‐taking behavior was defined by the number of items omitted by the student on the instrument designed for the purpose of assessing this behavior. The data were obtained from 89 students who were attending two colleges in upstate New York. The data consisted of SAT‐M scores and performance scores on a mathematics test designed to assess risk‐taking. A t‐test performed on the number of omissions revealed that females omit more items and thus manifest less risk‐taking behavior. A significant difference in favor of females omitting more items was found at the p < .01 level. A multiple regression design was employed, and gender and risk‐taking behavior were found to be significantly related at the p<.01 level to a student's performance on the SAT‐M.
Elementary School Chemistry: Has its Potential been Realized?
Authors: Skamp Keith
Published: March 2010

Examples of lesson sequences are described to illustrate how chemical content can be used with well established teaching‐learning models. These approaches place an emphasis on children constructing their own chemical ideas and using a wide range of science investigation skills. Mention is made of some literature which indicates the types of chemical ideas possessed by children. These results provide guidance for teachers, but hopefully readers will be challenged to see that while there is definitely a role for elementary school chemistry its full potential simply has not been realized.
Mathematics as Connection Making in Japanese Elementary Schools
Authors: Sawada Daiyo
Published: March 2010

Connection making is one of the major standards proposed by the National Council of Teachers of Mathematics, however, unlike problem solving, it has no long history of being designated as a goal of mathematics teaching. An examination of classroom observations of mathematics lessons taught in Japan reveal that connection making appears to be an implicit if not explicit standard for Japanese mathematics education. As a perspective from which to re‐examine and re‐assess our own practice, this paper describes several episodes of connection making as they occurred in Japanese elementary school classrooms. By reflecting upon the methods used in these classrooms, other approaches to connection making are suggested and explored.
Doing Is Believing: Do Laboratory Experiences Promote Conceptual Change?
Authors: Westbrook Susan L. , Rogers Laura N.
Published: March 2010

The present study examined whether notions students hold about scientific concepts are impacted by generating and testing hypotheses. Students enrolled in three ninth grade physical science classes were asked to select and test two student‐generated hypotheses concerning flotation. Conceptual change was assessed by concept maps and word sorting activities administered at three points in the investigation (pre, mid, and post). Lawson's Classroom Test of Scientific Reasoning (CTSR) and the Integrated Test of Process Skills (TIPS) were used to assess scientific reasoning ability and proficiency with science process skills, respectively. Twenty‐one of 63 students enrolled in the course completed the battery of assessment items and met the classroom attendance requirement. Those 21 students represented the data sample. Students selecting and investigating the hypothesis that weight determines an object's ability to float generally changed their notion of the relationship between weight and flotation. Students investigating the hypothesis that shape determines an object's ability to float did not exhibit conceptual change regarding shape.
Design of a Static TIM Tester
Authors: Székely V. , Kollár E. , Somlay G. , Szabó P. G. , Rencz M.
Published: March 2010

Testing the thermal properties of thermal interface material (TIM) has been a big challenge for decades. Recent development trends made this challenge even bigger, as now the values that have to be measured are extremely small. In this paper, we present a newly developed TIM tester equipment that is targeting to overcome all the problems that present industrial TIM testing methods face. The main idea behind our design is to use the capabilities of microelectronics in order to make small sized sensors both for temperature and heat-flux sensings. This way it is possible to place these sensors in the closest proximity of the measured sample. This paper presents details of all the technical solutions of the newly developed static TIM tester that is capable to measure Rth of unit area values in the order of 0.01 K cm2/W with good accuracy. Special attention is made to analyze and eliminate the possible sources of measurement inaccuracy. A number of measurement examples prove the usability of the developed measuring instrument.
Evaluation of Transverse Shear Effect on Film Delamination in Blister Test
Authors: Wang Wei , Huang Yong , Coutris Nicole , Noh Hongseok , Hesketh Peter J.
Published: March 2010

The transverse shear effect has been frequently ignored in determining the debonding-related energy release rate and the phase angle in the blister test, resulting in underestimated values. This study aims to study the effect of shear force on the energy release rate and phase angle prediction in the blister test. A generalized approach is proposed to predict them under the effect of shear force. The predictions show that when the ratio of the film thickness to the debonded film window radius is large (such as 0.05), the transverse shear effect cannot be ignored in determining the energy release rate and the phase angle. The study also further illustrates the importance of including the shear force contribution in estimation and how this importance depends on the film thickness to debonded radius ratio, as well as the elastic mismatch.
Evaluation of Stress Effects on Electrical Characteristics of N-Type MOSFETs: Variations of DC Characteristics During the Resin-Molding Process
Authors: Koganemaru Masaaki , Ikeda Toru , Miyazaki Noriyuki , Tomokage Hajime
Published: March 2010

Stress-induced changes in the electrical characteristics of a semiconductor device become a major concern in the production of semiconductor packages because the electrical characteristics are adversely affected by packaging (residual) stresses. The objective of our project is to evaluate the effects of stress on semiconductor devices. In this study, the shift of the DC characteristics of nMOSFETs during the resin-molding process was investigated experimentally. After a silicon chip including the n-type metal oxide semiconductor field effect transistors (nMOSFETs) was encapsulated in a quad flat package, the drain current variations and the transconductance shifts were measured. The drain current decreased during the resin-molding process while no significant shift in threshold voltage was observed. The experimental results were estimated adequately from the residual stress predicted by numerical and experimental analyses and from the stress-sensitivity of the nMOSFETs measured by the four-point bending method. Also, we tested the validity of an electron-mobility model that included the effect of stress. The electron-mobility model takes into account the variation in the relative occupancy of the electrons in each conduction-band energy valley. It was found that the effect of biaxial stress on the variation in electron-mobility can be qualitatively evaluated by the electron-mobility model but are quantitatively different from the experimental results. Several needed improvements to the electron-mobility model are proposed in this article.
Three-Dimensional Modeling of Mold Filling in Microchip Encapsulation Process With a Matrix-Array Arrangement
Authors: Abdullah M. K. , Abdullah M. Z. , Mujeebu M. A. , Gitano Horizon , Ariff Z. M. , Razali R. , Ahmad K. A.
Published: March 2010

A three-dimensional numerical model is developed to simulate the mold filling behavior in the plastic encapsulation of microchips. The conventional Hele–Shaw approximation is inadequate to analyze a complex molding compound flow behavior with multiple microchips in a single cavity. The developed numerical algorithm is based on the finite difference method combined with the robustness of volume of fluid volume-tracking method to solve the two-phase flow field in complex mold and die geometries. Twelve dies are arranged in a matrix-array in a single mold cavity. Short-shot experimental data are used to validate the numerical results for the melt flow front at different flow times. Close agreement between the experimental data and the numerical results demonstrates the applicability of the present computational model for the simulation of practical epoxy molding compound encapsulation.
An Inverse Problem in Estimating the Volumetric Heat Generation for a Three-Dimensional Encapsulated Chip
Authors: Huang Cheng-Hung , Chang Wei-Lun
Published: March 2010

A three-dimensional inverse heat conduction problem is solved in the present study by using the conjugate gradient method (CGM) and the general-purpose commercial code CFD−ACE+ to estimate the strength of the unknown heat generation for an encapsulated chip in a three-dimensional irregular domain. The advantage of calling CFD−ACE+ code as a subroutine in the present inverse calculation lies in that many difficult but practical 3D inverse problem can be solved under this construction since the general-purpose commercial code has the ability to solve the direct problem easily. The results obtained by using the CGM to solve this 3D inverse problem are justified based on the numerical experiments using the simulated exact and inexact measurements. It is concluded that reliable heat generation can be estimated by the present inverse algorithm.
Reliability Modeling of Lead-Free Solder Joints in Wafer-Level Chip Scale Packages
Authors: Zhao Jie-Hua , Gupta Vikas , Lohia Alok , Edwards Darvin
Published: March 2010

Board-level thermomechanical fatigue lifetimes of five different wafer-level chip scale packages (WCSPs) with lead-free solder joints were studied by both experiment and finite element method modeling. The effect of three different constitutive laws of the lead-free solder, namely Anand viscoplasticity, power law break-down creep, and time-hardening creep are also investigated for each of the five packages. The fatigue correlation parameters based on the increment of volume-averaged inelastic strain energy density are deduced for each of the corresponding three constitutive laws. It is demonstrated that the relative error of the predicted lifetime for WCSP with lead-free solder joints can be within 10% compared with experiment. It is found that the fatigue correlation parameters depend strongly on the specific constitutive law. Another important finding is that the fatigue correlation parameters depend on the specific package family. It is also demonstrated that when fatigue correlation parameters calibrated for other package families are applied to WCSPs, the error in predicted lifetimes is consistently large.
High Performance Anisotropic Conductive Adhesives Using Copper Particles With an Anti-Oxidant Coating Layer
Authors: Yim Myung Jin , Li Yi , Moon Kyoung Sik , Wong C. P.
Published: March 2010

This paper describes the development and characterization of anisotropically conductive films (ACFs) incorporated with copper (Cu) particles as electrically conductive fillers for environmentally friendly, low cost, high electrical, and high thermal interconnect applications in microelectronics packaging. The Cu particle surface modification by a coupling agent and its effects on the electrical conductivity and thermal stability of Cu-filled ACF joints were investigated for the potential alternatives of conventional Au-coated polymer and Au-coated Ni-filled ACFs. The surface characteristics of a thin film of the coupling agent on copper surfaces such as element analysis, their hydrophobicity, and thermal stability were evaluated. The treated Cu ball-filled ACF showed the lowest contact resistance 1.0×10−5 Ω, higher current carrying capability, and higher thermal stability of ACF joints compared with the conventional Au-coated polymer ball and Au-coated Ni ball-filled anisotropically conductive adhesives.
Determination of the Specific Heat Ratio of a Gas in a Plastic Syringe
Authors: Chamberlain Jeff
Published: March 2010

The rapid compression or expansion of a gas in a plastic syringe is a poor approximation of an adiabatic process. Heat exchange with the walls of the syringe brings the gas to equilibrium in an amount of time that is not significantly greater than the length of the compression or expansion itself. Despite this limitation, it is still possible to measure the pressure changes during a rapid change in volume and calculate an approximation of the pressures for an adiabatic process. From these values the specific heat ratio of the gas can be calculated.
Assessment of a Solar System Walk
Authors: LoPresto Michael C. , Murrell Steven R. , Kirchner Brian
Published: March 2010

The idea of sending students and the general public on a walk through a scale model of the solar system in an attempt to instill an appreciation of the relative scales of the sizes of the objects compared to the immense distances between them is certainly not new. A good number of such models exist, including one on the National Mall in Washington, D.C., starting at the Smithsonian Air and Space museum.1 A pioneering model and inspiration for our own is on the campus of the University of Colorado in Boulder,2 and there are others.3 Those at science museums are often used by the general public and field-trip groups, while the ones on college campuses are also used by students of introductory astronomy.
Reflection by Porro Prisms
Authors: Greenslade Thomas B.
Published: March 2010

Students all know that reflection from a plane mirror produces an image that is reversed right to left and so cannot be read by anyone but Leonardo da Vinci, who kept his notes in mirror writing. A useful counter-example is the Porro prism, which produces an image that is not reversed.
Battleship Buoyancy
Authors: Dishaw J. Patrick
Published: March 2010

One of the most dramatic demonstrations of the Archimedes principle is the simple fact that battleships float. I estimate the depth of a battleship in seawater as an example in my physics classes. I use the battleship Arizona as an exemplar of a class of U.S. battleships used during World War II. The Arizona was 608 ft (185.3 m) long and 97 ft 1 in (29.6 m) wide at its widest dimension. The unloaded weight of the ship was 31,400 U.S. tons (2.79× 108 N).1 How deep would the Arizona sink into seawater of density 1028 kg/m3?
Modeling the Motion of an Increasing Mass System
Authors: Kunkel William , Harrington Randal
Published: March 2010

Problems on the dynamics of changing mass systems often call for the more general form of Newton's second law1 Fnet = dpdt. These problems usually involve situations where the mass of the system decreases, such as in rocket propulsion. In contrast, this experiment examines a system where the mass increases at a constant rate and the net force remains constant. This system provides a context that is different, and in some ways simpler, than the rocket propulsion systems typically introduced in introductory courses.
Can We Trace Arbitrary Rays To Locate an Image Formed by a Thin Lens?
Authors: Suppapittayaporn Decha , Panijpan Bhinyo , Emarat Narumon
Published: March 2010

After learning how to trace the principal rays [Fig. 1(i)] through a thin lens in order to form the image in the conventional way, students sometimes ask whether it is possible to use other rays emanating from the object to form exactly the same image—for example, the two arbitrary rays shown in Fig. 1(ii). The answer is a definite yes, and this paper presents a method of doing so.
Getting Rid of Gravity — Alternative Ways of Looking at Trajectories
Authors: Dion Peter W. , Ho Anthony M. H.
Published: March 2010

Problems in projectile motion are a time-honored staple of high school and even first-year university physics. They can become confusing for some students, yet boring for the stronger students. Herein we present two alternative approaches to such questions, one we call “breaking down gravity,” which makes these questions easier to solve, and the other we call “getting rid of gravity,” which converts such questions into a more interesting and challenging form.
Functional Hierarchy and Reversibility Within the Murine Spermatogenic Stem Cell Compartment
Authors: Nakagawa Toshinori , Sharma Manju , Nabeshima Yo-ichi , Braun Robert E. , Yoshida Shosei
Published: March 2010

Sperm Production-Line Maintenance

The average man makes upwards of 1500 sperm per heartbeat. Such a feat requires a robust stem cell system. Using mice,

Nakagawa
et al.

(p.
62
, published online 18 March) shed light on some of the properties of the murine germline stem cell system that contribute to its robustness. During steady-state spermatogenesis, the majority of the stem cell population lies within a subset of cells called type A spermatogonia. However, during regeneration (for example, during recovery of the stem cell pool after drug exposure) the system in essence hijacks early-differentiating cells back into the stem cell compartment. Lineage analysis and live-imaging also suggests that during sperm production there is more than one path from a stem cell to differentiation.