bluuebunny/crossref_metadata_2025 huggingface dataset:
Identification of Rhodococcus equi lipids recognized by host cytotoxic T lymphocytes
Authors: Harris Seth P. , Fujiwara Nagatoshi , Mealey Robert H. , Alperin Debra C. , Naka Takashi , Goda Reina , Hines Stephen A.
Published: March 2010

Immune adult horses have CD8+cytotoxic T lymphocytes (CTLs) that recognize and lyseRhodococcus equi-infected cells in an equine lymphocyte alloantigen (ELA)-A [classical major histocompatibility complex (MHC) class I]-unrestricted fashion. As protein antigens are MHC class I-restricted, the lack of restriction suggests that the bacterial antigens being recognized by the host are not proteins. The goals of this study were to test the hypothesis that these CTLs recognize uniqueR. equicell-wall lipids related to mycobacterial lipids. Initial experiments showed that treatment of solubleR. equiantigen with broadly reactive proteases did not significantly diminish the ability of the antigen to stimulateR. equi-specific CTLs.R. equi-specific CTLs were also shown to lyse target cells (equine macrophages) pulsed with anR. equilipid extract. Analysis of theR. equilipid by TLC and MS (MALDI-TOF and ES) indicated that the extracted antigen consisted of three primary fractions: trehalose monomycolate (TMM), trehalose dimycolate (TDM) and cardiolipin (CL). ELA-A-mismatched cells pulsed with purified TMM and CL, but not the TDM fraction, were recognized and lysed byR. equi-specific CTLs. Because of their role in immune clearance and pathogenesis, transcription of the cytokines gamma interferon (IFN-γ) and interleukin-4 (IL-4) was also measured in response toR. equilipids by using real-time PCR; elevated IFN-γ, but not IL-4, was associated with host clearance of the bacteria. The whole-cellR. equilipid and all threeR. equilipid fractions resulted in marked increases in IFN-γtranscription, but no increase in IL-4 transcription. Together, these data support the hypothesis that immune recognition of unique lipids in the bacterial cell wall is an important component of the protective immune response toR. equi. The results also identify potential lipid antigens not previously shown to be recognized by CTLs in an important, naturally occurring actinomycete bacterial pathogen.
Comparison of promoter-specific events during transcription initiation in mycobacteria
Authors: China Arnab , Tare Priyanka , Nagaraja Valakunja
Published: March 2010

DNA–protein interactions that occur during transcription initiation play an important role in regulating gene expression. To initiate transcription, RNA polymerase (RNAP) binds to promoters in a sequence-specific fashion. This is followed by a series of steps governed by the equilibrium binding and kinetic rate constants, which in turn determine the overall efficiency of the transcription process. We present here the first detailed kinetic analysis of promoter–RNAP interactions during transcription initiation in the σ
A-dependent promoters P
rrnAPCL1
, P
rrnB
and P
gyr
of Mycobacterium smegmatis. The promoters show comparable equilibrium binding affinity but differ significantly in open complex formation, kinetics of isomerization and promoter clearance. Furthermore, the two rrn promoters exhibit varied kinetic properties during transcription initiation and appear to be subjected to different modes of regulation. In addition to distinct kinetic patterns, each one of the housekeeping promoters studied has its own rate-limiting step in the initiation pathway, indicating the differences in their regulation.
A chromodomain switch mediated by histone H3 Lys 4 acetylation regulates heterochromatin assembly
Authors: Xhemalce Blerta , Kouzarides Tony
Published: March 2010

Chromodomain proteins (Chp1/Chp2/Swi6/Clr4) bind to methylated H3K9 (H3K9me) and regulate pericentric heterochromatin in fission yeast. Chp1 and Clr4 (H3K9-HMT), bind transcriptionally active heterochromatin, whereas Chp2/Swi6 (HP1 homologs) are recruited during the inactive state. We show that H3K4 acetylation (H3K4ac) plays a role in the transition of dimethylated H3K9 (H3K9me2) occupancy from Chp1/Clr4 to Chp2/Swi6. H3K4ac, mediated by Mst1, is enriched at pericentromeres concomitantly with heterochromatin reassembly. H3K4R (Lys → Arg) mutation increases Chp1 and decreases Chp2/Swi6 pericentric occupancy and exhibits centromeric desilencing. Consistent with structural data, H3K4ac specifically reduces Chp1/Clr4 affinity to H3K9me. We propose that H3K4ac mediates a chromodomain switch from Chp1/Clr4 to Swi6/Chp2 to allow heterochromatin reassembly.
MicroRNAs coordinate an alternative splicing network during mouse postnatal heart development
Authors: Kalsotra Auinash , Wang Kun , Li Pei-Feng , Cooper Thomas A.
Published: March 2010

Alternative splicing transitions have been identified recently as a conserved component of vertebrate heart remodeling during postnatal development. Here we report that the targeted deletion of Dicer, specifically in adult mouse myocardium, reveals the role of microRNAs (miRNAs) in regulating networks of postnatal splicing transitions and in maintaining adult splicing programs. We demonstrate a direct role for miR-23a/b in the dramatic postnatal down-regulation of CUGBP and ETR-3-like factor (CELF) proteins that regulate nearly half of developmentally regulated splicing transitions in the heart. These findings define a hierarchy in which rapid postnatal up-regulation of specific miRNAs controls expression of alternative splicing regulators and the subsequent splicing transitions of their downstream targets.
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.
A SELF‐IMPROVEMENT SHEET IN BIOLOGY TEACHING IN THE SECONDARY SCHOOLS
Authors: Roberts Ernestine W.
Published: March 2010

[It is to be noted that in a paper of this type the different evaluations are subject to opinion and the evaluations given are not necessarily the correct ones. The set‐up and method of the author are highly commended. It will be stimulating for the reader to make his own evaluations and attempt to justify them in cases in which these differ from those given. Biol. Ed. note.]
SOME EFFECTIVE SCIENCE ACTIVITIES IN THE UPPER ELEMENTARY GRADES
Authors: Fahy Mildred
Published: March 2010

(This article is the third of a series of four articles of practical interest to elementary science teachers. Miss Fahy is the Principal of the Peirce N. E. A. and has had several years of experience in promoting the teaching of elementary science. The activities she describes have been used and have proved successful.

The first article of the series entitled “Adding Interest to the Elementary Science Classroom” by Dorothy Phipps appeared in the March issue. The second article gave suggestions for the care and handling of pets in the classroom and appeared in the April issue. The fourth and last article of the series will deal with science activities in the primary grades and will be in the June issue. D. W. R.)
Book Reviews
Authors: Shroyer Gail
Published: March 2010

Book reviewed in this article:

Slippery Babies: Young Frogs, Toads and Salamanders Ginny Johnson Judy Cutchins

When the Woods Hum Joanne Ryder
Software Reviews
Authors: McGrath Diane
Published: March 2010

Balance of the Planet Intellimation

The Wetlands Optical Data Corporation
Book Reviews
Authors: Shroyer Gail
Published: March 2010

Book reviewed in this article:

A History of Ideas in Science Education: Implications for Practice, George E. DeBoer

Exploring the Microscopic World, Joel Beller, Philip Weissman
Book Reviews
Authors: Shroyerm Gail
Published: March 2010

Book reviewed in this article:

Earth Science for Every Kid: 101 Easy Experiments That Really Work, Janice Pratt VanCleave.

Power Magic Science Activities for Children, Alisa Alexander and Susie Bower.
Software Reviews
Authors: McGrath Diane
Published: March 2010

A Field Trip into the Sea

Biology Explorer: Genetics
Problem Posing: A Neglected Component in Mathematics Courses for Prospective Elementary and Middle School Teachers
Authors: Gonzales Nancy A.
Published: March 2010

The purpose of this article is to describe a scheme which is designed to guide the prospective teacher beyond the point of proficiency as a student solving given problems. By experiencing several stages of inquiry, the scheme provides a mechanism where by the prospective teacher advances toward assuming the role of a teacher posing his or her own problems. Although the scheme has been developed within the context of a standard mathematics course for preservice teachers, the ideas set forth are equally appropriate for incorporation within a science course for prospective teachers.
The Circle of Apollonius: A Discovery Activity
Authors: Cain Ralph W.
Published: March 2010

The works of the Greek mathematician Apollonius offer many opportunities for conjecture regarding the discovery of geometric relationships. The “circle of Apollonius” can provide students a chance to use simple constructions and knowledge of proportions to discover an unexpected result, and, if desired, a chance to follow that discovery with a proof that what appears to be so is, indeed, the case. A minimum of prior knowledge is needed for the conjecturel discovery phase of this activity, while the proof requires a more solid background of Euclidean geometry. This exercise can lead to a number of other relationships and constructions found in the works of Apollonius.
The Value of Trade Books in Secondary Science and Mathematics Instruction: A Rationale
Authors: Daisey Peggy
Published: March 2010

A rationale for the inclusion of trade books (i.e., fiction, nonfiction, biographies, autobiographies, reports of discoveries, poetry, science fiction) is offered to secondary science and mathematics instructors. The benefits of trade books include context for problem posing and solving while promoting constructivist‐based instruction. Trade books provide students with vicarious experiences of the science and mathematics process, as they afford young people introductions to people and ideas which they may not know otherwise. Trade books promote positive attitudes toward science and mathematics instruction because they present a distinctive point of view and celebrate diversity of achievement. Trade books contain the ingredients necessary for emotional growth: romance, wonder and awe. In addition, trade books foster students' literacy development, since students are likely to conduct personalized inquiry, monitor their thinking and spend more time actively engaged in reading due to the variety and appeal of trade books. Importantly, teacher and student responses show reflection and ownership when trade books are used during instruction. Examples of books and quotes are included.
Changes in Preservice Elementary Teachers' Sense of Efficacy in Teaching Science
Authors: Ginns Ian S. , Tulip David F. , Watters James J. , Lucas Keith B.
Published: March 2010

This paper reports progress to date on a longitudinal study of changes in preservice teachers' sense of efficacy in teaching science. The study involved procedures designed to validate, in an Australian context, the Science Teaching Efficacy Beliefs Instrument (STEBI‐B) comprised of two scales: Personal Science Teaching Efficacy Belief Scale (STE) and Science Teaching Outcome Expectancy Scale (STO). Concomitantly, the instrument was used to monitor changes in teachers' sense of science teaching efficacy employing a pretest and repeated posttest, one group research design. The subjects were students enrolled in a three‐year Bachelor of Teaching (Primary) program. Correlations between pretest scores on STEBI‐B and other measures of personal beliefs and behaviors, namely academic self concept and academic locus of control, supported the validity of STEBI‐B. The results indicate that, over three semesters of the program, there was significant difference between the pretest and posttest scores on the STE scale. Possible explanations of the results obtained are discussed and evaluated and a justification for further long term research into teachers' sense of efficacy in teaching science is provided. Implications of the results for the teaching of elementary school science are discussed.
Heterogeneous Grouping as an Element of Cooperative Learning in an Elementary Education Science Course
Authors: Watson Scott B. , Marshall James E.
Published: March 2010

The purpose of this study was to clarify the effectiveness of heterogeneous grouping as an element of cooperative learning. A pretest‐posttest control group design was utilized. The independent variable was the method of arranging groups (heterogeneously or homogeneously). Dependent variables were scores from the NABT/NSTA Biology Exam (1987). Students were administered a questionnaire to determine perceptions of their cooperative learning situation. An analysis of covariance was used as the data analysis procedure for the experimental portion of the study. No significant differences in achievement were found between the two treatment conditions. Results from the student perceptions questionnaire did reveal substantial differences between students in the two treatment conditions, with generally more positive responses given by students in the homogeneous condition.
Elementary Preservice Teachers' Knowledge and Beliefs Regarding Science and Mathematics
Authors: Stevens Carol , Wenner George
Published: March 2010

The development of teacher education programs to better prepare elementary teachers requires an empirical base in which to anchor meaningful change. The research reported herein makes just such an effort. Preservice teachers' mathematics and science knowledge was measured as were their beliefs regarding instruction in these content areas. The results suggest that an increase in the number of college credit hours in science and mathematics content is less likely to effect necessary change than alteration of the methods and curriculum materials.
Ten Myths of Science: Reexamining What We Think We Know About the Nature of Science
Authors: McComas William F.
Published: March 2010

This article addresses and attempts to refute several of the most widespread and enduring misconceptions held by students regarding the enterprise of science. The ten myths discussed include the common notions that theories become laws, that hypotheses are best characterized as educated guesses, and that there is a commonly‐applied scientific method. In addition, the article includes discussion of other incorrect ideas such as the view that evidence leads to sure knowledge, that science and its methods provide absolute proof, and that science is not a creative endeavor. Finally, the myths that scientists are objective, that experiments are the sole route to scientific knowledge and that scientific conclusions are continually reviewed conclude this presentation. The paper ends with a plea that instruction in and opportunities to experience the nature of science are vital in preservice and inservice teacher education programs to help unseat the myths of science.
Classroom Observations of Middle School Students' Technology Use in Mathematics
Authors: Huang Shwu‐Yong L. , Waxman Hersholt C.
Published: March 2010

There have been many studies that have examined technology use in schools; most have relied on selfreport data from administrators, teachers, or students rather than on systematic classroom observations of technology use. The authors of the present study conducted systematic observations on 1,315 students from 220 middle school mathematics classrooms to examine the extent of technology use and whether there were gender, ethnic, or grade‐level differences related to the extent of students' use of technology. The descriptive results indicate that students used calculators about 25 percent of the time and computers less than 1 percent of the time in their mathematics classes. The multivariate analysis of variance results indicated no sex‐ or ethnicity‐related differences among students on their use of technology. Seventh grade students, however, were found to use calculators significantly more than sixth and eighth grade students.
Reflection and Problem Solving: Integrating Methods of Teaching Mathematics and Science
Authors: Stuessy Carol L. , Naizer Gilbert L.
Published: March 2010

An innovative teacher preparation course which integrates methods of teaching elementary mathematics and science was the context of this study. The course was developed as a prototype for the Teachers As Reflective Problem Solvers model for the preparation of elementary mathematics and science teachers. Data from 35 preservice elementary teachers' performance‐portfolios were analyzed to reveal patterns of change in their reflections and problem‐solving performance during the semester. Many of the students' reflections changed from task‐focused learning to broader teaching applications. No relationship was discerned between changes in students' reflections and changes in their levels of problem‐solving performance, although both increased during the semester. A significant correspondence was found, however, between students' perceptions of their problem‐solving abilities and their actual performance in solving teaching problems in integrated mathematics and science contexts.
Writing Collaborative Laboratory Reports in Ninth Grade Science: Three Case Studies of Social Interactions
Authors: Keys Carolyn W.
Published: March 2010

The purpose of this study was to investigate how collaborative peer discussion provided cognitive support for writing laboratory reports in ninth grade general science. The discourse of three pairs of students during collaborative writing sessions was analyzed to identify the types of social interactions in which the students engaged. These interactions were examined in relation to various intellectual demands of the laboratory reports and similarities and differences between the three pairs. Five types of interactions were identified and labeled as sounding board, peer teaching, supplies answer, debate, and incorporation. In general, student pairs used the constructive interactions of sounding board, peer teaching, and incorporation when writing difficult explanation and application sections of the reports. These interactions involved the processes of elaboration, explanation, and interpretation. Debate was used less frequently than the other interaction types, overall, and was hardly ever used by female pairs in the study. The results point to a high degree of interconnection between social interaction and cognitive processing.
Need New Problem‐Solving Ideas? Take a Trip!
Authors: Wiest Lynda R. , Sturbaum Mary Barr
Published: March 2010

The authors discuss how actual or planned travel experiences can form the basis for constructing realistic, challenging, and interesting problem‐solving tasks for classroom use. They discuss and provide examples of how teachers and students can create travel problems for use in the classroom. The travel‐problem concept is adaptable to any elementary, secondary, or post‐secondary classroom.
Korean and American Elementary School Teachers' Beliefs about Mathematics Problem Solving
Authors: Zambo Ron , Hong Eunsook
Published: March 2010

Elementary school teachers in South Korea and the United States completed a beliefs and practices questionnaire pertaining to mathematical problem‐solving instruction. Although both groups of teachers shared a general approach to teaching with a focus on problem‐solving strategies, many differences were apparent. Korean teachers rated themselves and their students higher in problem‐solving ability than American teachers. Korean teachers perceived their mathematics textbook as a more valuable source for problem‐solving instruction and word problems. Korean teachers more strongly agreed that students should know the key‐word approach for solving problems. American teachers reported more frequent use of calculators, manipulatives, and small group instruction. The results indicate that American teachers may more often use instructional techniques that are aligned with current recommendations for mathematics instruction.
Computer‐Assisted, Semi‐Programmed, and Teaching Assistant‐Led Instruction in General Chemistry
Authors: Cracolice Mark S. , Abraham Michael R.
Published: March 2010

The purpose of this study was to investigate computer‐assisted instruction and semi‐programmed instruction as replacements for traditional recitation/discussion in general chemistry. Student performance on problem solving and student attitudes were investigated. The study also examined the effect of formal reasoning ability as a covariate. The data indicated that for simple exercises, all methods of teaching recitation/discussion sections were equally effective, but for more difficult exercises, the semi‐programmed instruction was most effective. Students had more positive attitudes when using the semi‐programmed instruction than when attending traditional recitation/discussion sections.
Exploring Probability and Statistics with Preservice and Inservice Teachers
Authors: Quinn Robert J.
Published: March 2010

NCTM's mathematics curriculum and evaluation standards (1989) have provided educators with the challenge of revamping high school mathematics curricula as well as pedagogies by which content is taught. This article presents a lesson designed for preservice and inservice teachers that permits participants to: (a) strengthen their conceptual understanding, and (b) experience learning in a cooperative environment that encourages communication. The lesson engages participants in the collection and representation of probabilistic data using dice with 4, 6, 8, 10, 12, and 20 faces. Opportunities are provided for participants to discover patterns and construct mathematical knowledge concerning theoretical probability. Teacher educators can facilitate reform of mathematics education by developing and delivering such lessons.
Electromigration Simulation for Metal Lines
Authors: Jing JianPing , Liang Lihua , Meng Guang
Published: March 2010

As the electronics industry continues to push for high performance and miniaturization, the demand for higher current densities, which may cause electromigration failures in an IC, interconnects. Electromigration is a phenomenon that metallic atoms constructing the line are transported by electron wind. The damage induced by electromigration appears as the formation of voids and hillocks. A numerical simulation method for electromigration void incubation, and afterwards, void propagation, based on commercial software ANSYS Multiphysics and FORTRAN code, is presented in this paper. The electronic migration formulation considering the effects of the electron wind force, stress gradients, temperature gradients, and the atomic concentration gradient has been developed for the electromigration failure mechanisms. Due to introducing the atomic concentration gradient driving force in atomic flux formulations, the conventional atomic flux divergence method is no longer valid in electromigration (EM) simulation. Therefore, the corresponding EM atomic concentration redistribution algorithm is proposed using FORTRAN code. Finally, the comparison of voids generation through the numerical example of a standard wafer electromigration accelerated test (SWEAT) structure with the measurement result is discussed.
Teaching the Fundamentals of Cell Phones and Wireless Communications
Authors: Davids Mark , Forrest Rick , Pata Don
Published: March 2010

Wireless communications are ubiquitous. Students and teachers use iPhones®, BlackBerrys®, and other smart phones at home and at work. More than 275 million Americans had cell phones in June of 20091 and expanded access to broadband is predicted this year.2 Despite the plethora of users, most students and teachers do not understand “how they work.” Over the past several years, three high school teachers have collaborated with engineers at Cingular, Motorola, and the University of Michigan to explore the underlying science and design a three-week, student-centered unit with a constructivist pedagogy consistent with the “Modeling in Physics” philosophy.3 This unique pilot program reinforces traditional physics topics including vibrations and waves, sound, light, electricity and magnetism, and also introduces key concepts in communications and information theory. This article will describe the motivation for our work, outline a few key concepts with the corresponding student activities, and provide a summary of the program that has been developed to engage and inspire the next generation of scientists, engineers, and citizens.
Women and Men of the Manhattan Project
Authors: Marshall Jill , Herzenberg Caroline , Howes Ruth , Weaver Ellen , Gans Dorothy
Published: March 2010

In the early 1990s Ruth Howes, a nuclear physicist on the faculty at Ball State University, and Caroline Herzenberg, a nuclear physicist at Argonne National Laboratory, were asked to write a chapter on the Manhattan Project for a volume on women working on weapons development for the military.1 Realizing that they knew very little about the women who had been involved in that effort, they embarked on a mission to find out more. Howes and Herzenberg were able to document the wartime contributions of more than 1000 women in Their Day in the Sun,2 preserving this legacy for generations to come. At the 2009 AAPT Winter Meeting in Chicago, the AAPT Committee on Women in Physics celebrated the accomplishments of these women and the men who worked beside them in a session co-sponsored with the History and Philosophy of Physics and the Concerns of Senior Physicists committees. Howes presented an overview of the contributions of women to the development of the first nuclear weapon, and the session was honored with the presence of Manhattan Project veterans Ellen Cleminshaw Weaver, who worked at Oak Ridge, and Dorothy Marcus Gans, who worked as a technician in the Metallurgical Laboratory in Chicago.
An apparatus to simulate an amusement park rotor
Authors: Saraiva Carlos
Published: March 2010

The rotor is a device that can be found in many amusement parks.1 In the literature there are various articles about this topic. The rotor is a hollow cylindrical room, covered inside with canvas and which can be rotated about the central vertical axis. People stand upright, with their backs against the internal face of the device. When it reaches a certain angular speed, the floor moves down and people don't fall; they are apparently stuck to the walls of the rotating cylinder.
Heritable Individual-Specific and Allele-Specific Chromatin Signatures in Humans
Authors: McDaniell Ryan , Lee Bum-Kyu , Song Lingyun , Liu Zheng , Boyle Alan P. , Erdos Michael R. , Scott Laura J. , Morken Mario A. , Kucera Katerina S. , Battenhouse Anna , Keefe Damian , Collins Francis S. , Willard Huntington F. , Lieb Jason D. , Furey Terrence S. , Crawford Gregory E. , Iyer Vishwanath R. , Birney Ewan
Published: March 2010

Like Father, Like Mother, Like Child

Transcriptional regulation is mediated by chromatin structure, which may affect the binding of transcription factors, but the extent of how individual-to-individual genetic variation affects such regulation is not well understood.

Kasowski
et al.

(p.
232
, published online 18 March) investigated the binding of two transcription factors across the genomes of human individuals and one chimpanzee. Transcription factor binding was associated with genomic features such as nucleotide variation, insertions and deletions, and copy number variation. Thus, genomic sequence variation affects transcription factor binding and may explain expression difference among individuals.

McDaniell
et al.

(p.
235
, published online 18 March) provide a genome-wide catalog of variation in chromatin and transcription factor binding in two parent-child trios of European and African ancestry. Up to 10% of active chromatin binding sites were specific to a set of individuals and were often inherited. Furthermore, variation in active chromatin sites showed heritable allele-specific correlation with variation in gene expression.
A Six Sigma approach to the rate and clinical effect of registration errors in a laboratory
Authors: Vanker Naadira , van Wyk Johan , Zemlin Annalise E , Erasmus Rajiv T
Published: March 2010

Background

Laboratory errors made during the pre-analytical phase can have an impact on clinical care. Quality management tools such as Six Sigma may help improve error rates.

Aim

To use elements of a Six Sigma model to establish the error rate of test registration onto the laboratory information system (LIS), and to deduce the potential clinical impact of these errors.

Methods

In this retrospective study, test request forms were compared with the tests registered onto the LIS, and all errors were noted before being rectified. The error rate was calculated. The corresponding patient records were then examined to determine the actual outcome, and to deduce the potential clinical impact of the registration errors.

Results

Of the 47 543 tests requested, 72 errors were noted, resulting in an error rate of 0.151%, equating to a sigma score of 4.46. The patient records reviewed indicated that these errors could, in various ways, have impacted on clinical care.

Conclusion

This study highlights the clinical effect of errors made during the pre-analytical phase of the laboratory testing process. Reduction of errors may be achieved through implementation of a Six Sigma programme.
Multifocal polypoid endometriosis in a young woman simulating vaginal and pelvic neoplasm
Authors: Kaushal Seema , Dadhwal Vatsla , Mathur Sandeep R , Ray Ruma , Durgapal Prashant , Deka Deepika
Published: March 2010

A 27-year-old nulliparous woman presented with large finger-like projections protruding from her vagina. Intraoperatively there were deposits in the pouch of Douglas. Clinical presentation and history of vaginal bleeding suggested malignancy. Histopathology of both the vaginal and pouch of Douglas masses showed endometrial glands and stroma. There was no architectural complexity or cytological atypia of glands or stroma. Immunohistochemistry for oestrogen receptor, progesterone receptor and CD10 was positive. Based on morphological and immunohistochemical findings, multifocal polypoid endometriosis was diagnosed; this is a recently described entity having a clinical presentation and age range completely different from conventional or non-polypoid endometriosis. Although an association between tamoxifen use, unopposed oestrogen therapy and polypoid endometriosis has been suggested, the patient had no history of tamoxifen or oestrogen intake. Polypoid endometriosis should be part of the differential diagnosis in young women presenting with vaginal growth.
THE HOMOTOPY GROUPS OF THE L2-LOCALIZATION OF THE MODULO p MOORE SPECTRUM SMASHING WITH THE FIRST RAVENEL SPECTRUM
Authors: Ichigi Ippei , Shimomura Katsumi
Published: March 2010

Let BP be the Brown-Peterson spectrum at an odd prime p, and L2 denote the Bousfield localization functor with respect to [Formula: see text]. The Ravenel spectrum T(1) is characterized by BP*(T(1)) = BP*[t1] on the primitive generator t1. In this paper, we determine the homotopy groups π*(L2M ∧ T(1)) for the mod p Moore spectrum M.
Device transparency
Authors: Strauss Jacob , Lesniewski-Laas Chris , Paluska Justin Mazzola , Ford Bryan , Morris Robert , Kaashoek Frans
Published: March 2010

This paper proposes a new storage model,
device transparency
, in which users view and manage their entire data collection from any of their devices, even from disconnected storage-limited devices holding only a subset of the entire collection.
Does virtualization make disk scheduling passé?
Authors: Boutcher David , Chandra Abhishek
Published: March 2010

We examine whether traditional disk I/O scheduling still provides benefits in a layered system consisting of virtualized operating systems and underlying virtual machine monitor. We demonstrate that choosing the appropriate scheduling algorithm in guest operating systems provides performance benefits, while scheduling in the virtual machine monitor has no measurable advantage. We propose future areas for investigation, including schedulers optimized for running in a virtual machine, for running in a virtual machine monitor, and layered schedulers optimizing both application level access and the underlying storage technology.
Why panic()?
Authors: Sundararaman Swaminathan , Subramanian Sriram , Rajimwale Abhishek , Arpaci-Dusseau Andrea C. , Arpaci-Dusseau Remzi H. , Swift Michael M.
Published: March 2010

The file system is one of the most critical components of the operating system. Almost all applications running in the operating system require file systems to be available for their proper operation. Though file-system availability is critical in many cases, very little work has been done on tolerating file system crashes. In this paper, we propose Membrane, a set of changes to the operating system to support restartable file systems. Membrane allows an operating system to tolerate a broad class of file system failures and does so while remaining transparent to running applications; upon failure, the file system restarts, its state is restored, and pending application requests are serviced as if no failure had occurred. Our initial evaluation ofMembrane with ext2 shows thatMembrane induces little performance overhead and can tolerate a wide range of file system crashes. More critically, Membrane does so with few changes to ext2, thus improving robustness to crashes without mandating intrusive changes to existing filesystem code.
SelfTalk for Dena
Authors: Ghanbari Saeed , Soundararajan Gokul , Amza Cristiana
Published: March 2010

We introduce SelfTalk, a novel declarative language that allows users to query and understand the status of a large scale system. SelfTalk is sufficiently expressive to encode an administrator's high level hypotheses/expectations about normal system behavior, such as, "I expect that the throughputs across all system components are linearly correlated". SelfTalk works in conjunction with Dena, a runtime support system designed to help system administrators detect the root cause of system misbehavior quickly and accurately. Given a user hypothesis, Dena instantiates and validates it using actual monitored data within specific system contexts. We evaluate Dena by posing several hypotheses about system behavior and querying Dena to diagnose anomalies in a virtual storage system. We find that Dena can automatically validate the system performance based on the user hypotheses and also accurately diagnose system misbehavior.
Efficiency matters!
Authors: Anderson Eric , Tucek Joseph
Published: March 2010

Current data intensive scalable computing (DISC) systems, although scalable, achieve embarrassingly low rates of processing per node. We feel that current DISC systems have repeated a mistake of old high-performance systems: focusing on scalability without considering efficiency. This poor efficiency comes with issues in reliability, energy, and cost. As the gap between theoretical performance and what is actually achieved has become glaringly large, we feel there is a pressing need to rethink the design of future data intensive computing and carefully consider the direction of future research.
An energy case for hybrid datacenters
Authors: Chun Byung-Gon , Iannaccone Gianluca , Iannaccone Giuseppe , Katz Randy , Lee Gunho , Niccolini Luca
Published: March 2010

Reducing energy consumption in datacenters is key to building low cost datacenters. To address this challenge, we explore the potential of hybrid datacenter designs that mix low power platforms with high performance ones. We show how these designs can handle diverse workloads with different service level agreements in an energy efficient fashion. We evaluate the feasibility of our approach through experiments and then discuss the design challenges and options of hybrid datacenters.
Incremental learning of system log formats
Authors: Zhu Kenny Q. , Fisher Kathleen , Walker David
Published: March 2010

System logs come in a large and evolving variety of formats, many of which are semi-structured and/or non-standard. As a consequence, off-the-shelf tools for processing such logs often do not exist, forcing analysts to develop their own tools, which is costly and timeconsuming. In this paper, we present an incremental algorithm that automatically infers the format of system log files. From the resulting format descriptions, we can generate a suite of data processing tools automatically. The system can handle large-scale data sources whose formats evolve over time. Furthermore, it allows analysts to modify inferred descriptions as desired and incorporates those changes in future revisions.
Mining dependency in distributed systems through unstructured logs analysis
Authors: Lou Jian-Guang , Fu Qiang , Wang Yi , Li Jiang
Published: March 2010

Dependencies among system components are crucial to locating root errors in a distributed system. In this paper, we propose an approach to mine intercomponent dependencies from unstructured logs. The technique requires neither additional system instrumentation nor any application specific knowledge. In the approach, we first parse each log message into its log key and parameters. Then, we find dependent log key pairs belong to different components by leveraging co-occurrence analysis and parameter correspondence. After that, we use Bayesian decision theory to estimate the dependency direction of each dependent log key pair. We further apply time delay consistency to remove false positive detections. Case studies on Hadoop show that the technique successfully identifies the dependencies among the distributed system components.
Roadcast
Authors: Zhang Yang , Zhao Jing , Cao Guohong
Published: March 2010

Content sharing through vehicle-to-vehicle communication can help people find their interested content on the road. In VANETs, due to limited contact duration time and the unreliable wireless connection, a vehicle can only get the useful data when it meets the vehicle which has the exactly matching data. However, the probability of such cases is very low. To improve the performance of content sharing in intermittently connected VANETs, we propose a novel P2P content sharing scheme called Roadcast. Roadcast relaxes user's query requirement a little bit so that each user can have more chances to get the requested content quickly. Furthermore, Roadcast ensures popular data is more likely to be shared with other vehicles so that the performance of overall query delay can be improved. Roadcast consists of two components called popularity aware content retrieval and popularity aware data replacement. The popularity aware content retrieval scheme makes use of Information Retrieval (IR) techniques to find the most relevant data towards user's query, but significantly different from IR techniques by taking the data popularity factor into consideration. The popularity aware data replacement algorithm ensures that the density of different data is proportional to the square-root of their popularity in the system steady state, which firmly obeys the optimal "square-root" replication rule [6]. Results based on real city map and real traffic model show that Roadcast outperforms other content sharing schemes in VANETs.
Probiotic bacteria and intestinal epithelial barrier function
Authors: Ohland Christina L. , MacNaughton Wallace K.
Published: March 2010

The intestinal tract is a diverse microenvironment where more than 500 species of bacteria thrive. A single layer of epithelium is all that separates these commensal microorganisms and pathogens from the underlying immune cells, and thus epithelial barrier function is a key component in the arsenal of defense mechanisms required to prevent infection and inflammation. The epithelial barrier consists of a dense mucous layer containing secretory IgA and antimicrobial peptides as well as dynamic junctional complexes that regulate permeability between cells. Probiotics are live microorganisms that confer benefit to the host and that have been suggested to ameliorate or prevent diseases including antibiotic-associated diarrhea, irritable bowel syndrome, and inflammatory bowel disease. Probiotics likely function through enhancement of barrier function, immunomodulation, and competitive adherence to the mucus and epithelium. This review summarizes the evidence about effects of the many available probiotics with an emphasis on intestinal barrier function and the mechanisms affected by probiotics.
Modulatory effect of curcumin on survival of irradiated human intestinal microvascular endothelial cells: role of Akt/mTOR and NF-κB
Authors: Rafiee Parvaneh , Binion David G. , Wellner Michael , Behmaram Behnaz , Floer Martin , Mitton Elizabeth , Nie Linghui , Zhang Zhihong , Otterson Mary F.
Published: March 2010

Radiation therapy is an essential modality in the treatment of colorectal cancers. Radiation exerts an antiangiogenic effect on tumors, inhibiting endothelial proliferation and survival in the tumor microvasculature. However, damage from low levels of irradiation can induce a paradoxical effect, stimulating survival in endothelial cells. We used human intestinal microvascular endothelial cells (HIMEC) to define effects of radiation on these gut-specific endothelial cells. Low-level irradiation (1–5 Gy) activates NF-κB and the phosphatidylinositol 3-kinase (PI3K)/Akt pathway, which is involved in cell cycle reentry and cell survival in HIMEC. A downstream target of PI3K/Akt is mammalian target of rapamycin (mTOR), which contributes to endothelial proliferation and angiogenesis. The aim of this study was to investigate the signaling molecules involved in the radiosensitizing effects of curcumin on HIMEC subjected to low levels of irradiation. We have demonstrated that exposure of HIMEC to low levels of irradiation induced Akt and mTOR phosphorylation, which was attenuated by curcumin, rapamycin, LY294002, and mTOR small interference RNA (siRNA). Activation of NF-κB by low levels of irradiation was inhibited by curcumin, SN-50, and mTOR siRNA. Curcumin also induced apoptosis by induction of caspase-3 cleavage in irradiated HIMEC. In conclusion, curcumin significantly inhibited NF-κB and attenuated the effect of irradiation-induced prosurvival signaling through the PI3K/Akt/mTOR and NF-κB pathways in these gut-specific endothelial cells. Curcumin may be a potential radiosensitizing agent for enhanced antiangiogenic effect in colorectal cancer radiation therapy.
A phenomenological model that predicts forces generated when electrical stimulation is superimposed on submaximal volitional contractions
Authors: Perumal Ramu , Wexler Anthony S. , Kesar Trisha M. , Jancosko Angela , Laufer Yocheved , Binder-Macleod Stuart A.
Published: March 2010

Superimposition of electrical stimulation during voluntary contractions is used to produce functional movements in individuals with central nervous system impairment, to evaluate the ability to activate a muscle, to characterize the nature of fatigue, and to improve muscle strength during postsurgical rehabilitation. Currently, the manner in which voluntary contractions and electrically elicited forces summate is not well understood. The objective of the present study is to develop a model that predicts the forces obtained when electrical stimulation is superimposed on a volitional contraction. Quadriceps femoris muscles of 12 able-bodied subjects were tested. Our results showed that the total force produced when electrical stimulation was superimposed during a volitional contraction could be modeled by the equation T = V + S[(MaxForce − V)/MaxForce]N, where T is the total force produced, V is the force in response to volitional contraction alone, S is the force response to the electrical stimulation alone, MaxForce is the maximum force-generating ability of the muscle, and N is a parameter that we posit depends on the differences in the motor unit recruitment order and firing rates between volitional and electrically elicited contractions. In addition, our results showed that the model predicted accurately (intraclass correlation coefficient ≥0.97) the total force in response to a wide range of stimulation intensities and frequencies superimposed on a wide range of volitional contraction levels. Thus the model will be helpful to clinicians and scientists to predict the amount of stimulation needed to produce the targeted force levels in individuals with partial paralysis.
Is interindividual variability of EMG patterns in trained cyclists related to different muscle synergies?
Authors: Hug François , Turpin Nicolas A. , Guével Arnaud , Dorel Sylvain
Published: March 2010

Our aim was to determine whether muscle synergies are similar across trained cyclists (and thus whether the same locomotor strategies for pedaling are used), despite interindividual variability of individual EMG patterns. Nine trained cyclists were tested during a constant-load pedaling exercise performed at 80% of maximal power. Surface EMG signals were measured in 10 lower limb muscles. A decomposition algorithm (nonnegative matrix factorization) was applied to a set of 40 consecutive pedaling cycles to differentiate muscle synergies. We selected the least number of synergies that provided 90% of the variance accounted for VAF. Using this criterion, three synergies were identified for all of the subjects, accounting for 93.5 ± 2.0% of total VAF, with VAF for individual muscles ranging from 89.9 ± 8.2% to 96.6 ± 1.3%. Each of these synergies was quite similar across all subjects, with a high mean correlation coefficient for synergy activation coefficients (0.927 ± 0.070, 0.930 ± 0.052, and 0.877 ± 0.110 for synergies 1– 3, respectively) and muscle synergy vectors (0.873 ± 0.120, 0.948 ± 0.274, and 0.885 ± 0.129 for synergies 1– 3, respectively). Despite a large consistency across subjects in the weighting of several monoarticular muscles into muscle synergy vectors, we found larger interindividual variability for another monoarticular muscle (soleus) and for biarticular muscles (rectus femoris, gastrocnemius lateralis, biceps femoris, and semimembranosus). This study demonstrated that pedaling is accomplished by the combination of the similar three muscle synergies among trained cyclists. The interindividual variability of EMG patterns observed during pedaling does not represent differences in the locomotor strategy for pedaling.