bluuebunny/crossref_metadata_2025 huggingface dataset:
Practicing Reliability
Authors: Adams Samantha , Bal Roland
Published: February 2008

The availability of medical and health information on the world wide web has led to a long discussion about the reliability of that information. Various medical, political, and independent organizations have created user-friendly tools for finding reliable medical/health information on the web and have been faced with the challenge of (re)defining what it means for information to be reliable. Little attention has been given to the work of reviewing web-based information and applying selection criteria to individual sites. In this article, the authors examine how guidelines are applied in practice and discuss how the selection criteria and the practices of applying them reinforce distinctions (such as those between lay and expert, global and local, nonprofit and commercial, etc.) that current medical sociology and informatics literature suggests have been broken down by internet technologies and the availability of web-based medical information.
Comparison of Cutaneous and Transosseous Electromagnetic Position Sensors in the Assessment of Tibial Rotation in a Cadaveric Model
Authors: Magit David P. , McGarry Michelle , Tibone James E. , Lee Thay Q.
Published: February 2008

Background

Recent studies have highlighted the growing interest in validating anatomic anterior cruciate ligament reconstructions. A simple method of measuring tibial rotation is necessary to provide an objective clinical assessment of restoration of normal knee kinematics after various anterior cruciate ligament reconstructive techniques.

Objective

To validate a new method of measuring tibial rotation by comparing cutaneous with transosseous electromagnetic position sensors during a simulated standard knee examination.

Study Design

Controlled laboratory study.

Methods

Eight thawed, fresh-frozen cadaveric knee specimens with skin and soft tissues preserved were mounted on the femoral side in neutral rotation by a rigid clamp, allowing 6 degrees of freedom of the knee joint. With the knee fixed at 30° of flexion, a series of maximal manual internal and external tibial rotations were performed and measured with an electromagnetic tracking system that measures 6 degrees of freedom in a Cartesian coordinate system. During each series of measurements, a cutaneous transmitter was fixed overlying the tibial tuberosity. Simultaneously, a second transducer was rigidly fixed to a transosseous pin placed just distal to the tibial tubercle. Measurements were repeated at 90° of flexion. Differences in measurements were assessed.

Results

No significant differences were found with maximal internal and external rotation between cutaneous and transosseous measurements at 30° of knee flexion (13.0° vs 14.5°, P = .4) or at 90° of flexion (11.2° vs 12.9°, P = .5). Correlation ( R) between cutaneous and transosseous measurements at 30° was .97 ( P = .00009) and at 90° was .99 ( P < .00001). The accuracy of cutaneous measurements using transosseous as the known was 1.6° ± 1.3°. Repeatability of cutaneous measurements was 0.8° ± 0.4°. The repeatability of transosseous measurements was 1.0° ± 0.5°.

Conclusion

No significant differences were found at either 30° or 90° of flexion when measuring tibial rotation using cutaneous versus transosseous electromagnetic position sensors.

Clinical Relevance

The ability to measure knee rotation using cutaneous electromagnetic position sensors represents a promising new method for assessing various clinical conditions and surgical outcomes.
Dreams Deferred?
Authors: Asha Cooper Michelle
Published: February 2008

This study uses data from the Educational Longitudinal Study of 2002 to test a conceptual model that integrates aspects of sociological and econometric frameworks into a traditional status attainment model for educational aspirations. Using descriptive and logistic analyses, this study advanced understanding of the patterns and stability of aspirations; characteristics of students who increase, decrease, and maintain aspirations; predictors of 12th-grade aspirations; and variations in predictors of 12th-grade aspirations by race/ ethnicity. The study's findings have implications for policy, practice, and research. Specifically, the findings reinforce the need for policies and practices geared toward enhancing existing high school reform efforts. The study also identifies recommendations for future research.
What Do We Really Know About the Outcomes of Australian International Education? A Critical Review and Prospectus for Future Research
Authors: Cuthbert Denise , Smith Wendy , Boey Janice
Published: February 2008

Australia has been a significant provider of international education in the Asia-Pacific region since 1950 with the inception of the Colombo Plan. Thus, graduates from these early days would by now be mature professionals in a variety of fields, with several decades of professional and academic attainment enabled by their Australian education. Yet we actually know very little about the outcomes over time of the graduates of Australian international higher education. In this article, the authors review the scholarly literature on the outcomes of international education, education provided by Australian universities and by others, and critically consider some of the limitations of the data and the methodologies that have dominated this area of research. Finally, in an effort to put current debates on international education on a more informed basis, the authors outline a prospectus for future research to redress some of these shortcomings.
Primary Prevention of Skin Cancer in Children and Adolescents: A Review of the Literature
Authors: Hart Kristen M. , DeMarco Rosanna F.
Published: February 2008

Although skin cancer is an easily preventable disease, self-directed prevention behaviors in children are difficult to achieve. The purpose of this article is to evaluate the status of primary prevention interventions and identify gaps in national and international research in order to make suggestions for further intervention design. A comprehensive search of MEDLINE, CINAHL, and PSYCHinfo databases was conducted to collect published research used in this review. The most effective interventions used multicomponent curricula administered over an extended period of time. Younger children were more receptive to interventions than were older children, who had stronger attitudes against sun-protective behaviors. Interventions in Australia have been more successful than interventions in North America and Europe. Further research needs to be conducted to create primary prevention interventions that address informational gaps. Specifically testing the dose and effect of individual educational components and bundling of components with reliable and valid outcome measures would help health care researchers define and measure the most effective way to battle social norms and attitudes of children and sun exposure.
Dimensions of Majority and Minority Groups
Authors: Seyranian Viviane , Atuel Hazel , Crano William D.
Published: February 2008

Several definitions of majority and minority groups can be found in the social psychological literature. They involve numeric size, power/status, and counternormative position, but size is most commonly used in experimental research to manipulate minority/minority status. Does this practice mirror real-world conceptualizations? To address this question, 77 participants were asked to describe majority and minority groups using a structured openended measure. Content analysis of their responses revealed that majority and minority groups were conceptualized along eight dimensions, which included power, number, distinctiveness, social category, group context, dispositions, and being the source or target of behavior. Although these dimensions were relevant to both majorities and minorities, they often were applied differentially. Also, minorities were associated with more divergent thinking and viewed more negatively than were majorities. On the basis of these findings, a new typology of groups was proposed that could be used in future experimental research to advance our understanding of majorities and minorities.
The Structure of Conflict over EU Chemicals Policy
Authors: Lindgren Karl-Oskar , Persson Thomas
Published: February 2008

There is a lively academic debate over whether political cleavages in the European Union (EU) follow mainly territorial (national) or non-territorial (ideological) patterns. This article analyses the cleavages that structure the conflict over European chemicals policy, the so-called REACH system. Taking positions on this major policy as an empirical example, we test these competing theories on the nature of cleavages on environmental policy issues in the EU. We use data from an expert survey of more than 600 individuals to fulfil this aim. The results show that neither of the hypotheses is unequivocally supported. But the data indicate that cleavages based on non-territorial interests are much more important than territorial interests in explaining positions on REACH.
Measuring perceived stigma in persons with progressive neurological disease
Authors: Burgener Sandy C. , Berger Barbara
Published: February 2008

The perceived stigma inherent in progressive neurological diseases, such as Alzheimer's dementia (AD) and Parkinson's Disease (PD), has been under-recognized. The purposes of this pilot study were to examine: (1) the psychometric properties of the Stigma Impact (SIS) and Stigma Experience Scales (SES) when used with persons with AD or PD; and (2) differences in perceived stigma by disease diagnosis. The sample included 26 persons with AD and 14 persons with PD. Findings support the reliability of the total SIS scale for both persons with AD or PD. The four SIS subscales had acceptable reliability when used with persons with PD, while two of the four subscales had adequate reliability when used with persons with AD. Internal consistency reliability of the SES was acceptable in PD sample only. Validity of the total SIS scale and the four subscales was supported through significant correlations with mental status (AD sample only), self-esteem, depression, and personal control. Persons with AD scored higher on the SIS internalized shame subscale and lower on personal control compared to persons with PD. Overall, support was found for the SIS as a reliable and valid measure of perceived stigma in persons with AD or PD. The magnitude of perceived stigma in persons with AD is comparable to or greater than other populations of persons with chronic illness, including cancer and PD.
the role of international expert
Authors: Penn Helen
Published: February 2008

This article reviews Sally Lubeck's international contributions. It describes her role as rapporteur for the OECD review of early education and care services in the UK, one of 20 such reviews commissioned by the OECD. It discusses the continued relevance of her observations and comments on provision in the UK. The article goes on to comment briefly on her insights into the role of international agencies more generally, and the difficulties of knowledge transfer not only between the rich countries of the OECD but between rich and poor countries across the world.
Pigskins and Politics
Authors: Laband David N. , Pandit Ram , Laband Anne M. , Sophocleus John P.
Published: February 2008

In this article, the authors use data collected from nearly 4,000 single-family residences in Auburn, Alabama to investigate empirically whether nonpolitical expressiveness (displaying support for Auburn University's football team outside one's home) is related to the probability that at least one resident voted in the national/state/local elections held on November 7, 2006. Controlling for the assessed value of the property and the length of ownership, the authors find that the likelihood of voting by at least one person from a residence with an external display of support for Auburn University is nearly 2 times greater than from a residence without such a display. This suggests that focusing narrowly on voting as a reflection of political expressiveness may lead researchers to overstate the relative importance of expressiveness in the voting context and understate its more fundamental and encompassing importance in a variety of contexts, only one of which may be voting.
Identification of discrete tumor-induced myeloid-derived suppressor cell subpopulations with distinct T cell–suppressive activity
Authors: Movahedi Kiavash , Guilliams Martin , Van den Bossche Jan , Van den Bergh Rafael , Gysemans Conny , Beschin Alain , De Baetselier Patrick , Van Ginderachter Jo A.
Published: February 2008

The induction of CD11b+Gr-1+ myeloid-derived suppressor cells (MDSCs) is an important immune-evading mechanism used by tumors. However, the exact nature and function of MDSCs remain elusive, especially because they constitute a heterogeneous population that has not yet been clearly defined. Here, we identified 2 distinct MDSC subfractions with clear morphologic, molecular, and functional differences. These fractions consisted of either mononuclear cells (MO-MDSCs), resembling inflammatory monocytes, or low-density polymorphonuclear cells (PMN-MDSCs), akin to immature neutrophils. Interestingly, both MO-MDSCs and PMN-MDSCs suppressed antigen-specific T-cell responses, albeit using distinct effector molecules and signaling pathways. Blocking IFN-γ or disrupting STAT1 partially impaired suppression by MO-MDSCs, for which nitric oxide (NO) was one of the mediators. In contrast, while IFN-γ was strictly required for the suppressor function of PMN-MDSCs, this did not rely on STAT1 signaling or NO production. Finally, MO-MDSCs were shown to be potential precursors of highly antiproliferative NO-producing mature macrophages. However, distinct tumors differentially regulated this inherent MO-MDSC differentiation program, indicating that this phenomenon was tumor driven. Overall, our data refine tumor-induced MDSC functions by uncovering mechanistically distinct MDSC subpopulations, potentially relevant for MDSC-targeted therapies.
Dynamic imaging of fibrin network formation correlated with other measures of polymerization
Authors: Chernysh Irina N. , Weisel John W.
Published: February 2008

Using deconvolution microscopy, we visualized in real time fibrin network formation in the hydrated state. Individual mobile fibers were observed before the gel point determined by eye. After gelation, an initial fibrin network was seen, which evolved over time by addition of new fibers and elongation and branching of others. Furthermore, some fibers in the network moved for a time. We quantified network formation by number of branch points, and longitudinal and lateral growth of fibers. Eighty percent of branch points were formed, and 70% of all fibers reached their maximum length at the gel point. In contrast, at the gel point, fiber diameter, measured as fluorescence intensity, was less than 25% and turbidity was less than 15% of the maximum values of the fully formed clot. The cumulative percentage of fibers reaching their final length and the number of branch points attained maximum values at 60% of maximum turbidity. Lateral fiber growth reached a plateau at the same time as turbidity. Measurements of clot mechanical properties revealed that the clots achieved maximum stiffness and minimum plasticity after the structural parameters reached their maxima. These results provide new information on the relative time sequence of events during fibrin network formation.
Genetic and genomic analysis modeling of germline c-MYC overexpression and cancer susceptibility
Authors: Solé Xavier , Hernández Pilar , de Heredia Miguel López , Armengol Lluís , Rodríguez-Santiago Benjamín , Gómez Laia , Maxwell Christopher A , Aguiló Fernando , Condom Enric , Abril Jesús , Pérez-Jurado Luis , Estivill Xavier , Nunes Virginia , Capellá Gabriel , Gruber Stephen B , Moreno Víctor , Pujana Miguel Angel
Published: February 2008

Background

Germline genetic variation is associated with the differential expression of many human genes. The phenotypic effects of this type of variation may be important when considering susceptibility to common genetic diseases. Three regions at 8q24 have recently been identified to independently confer risk of prostate cancer. Variation at 8q24 has also recently been associated with risk of breast and colorectal cancer. However, none of the risk variants map at or relatively close to known genes, with c-MYC mapping a few hundred kilobases distally.

Results

This study identifies cis-regulators of germline c-MYC expression in immortalized lymphocytes of HapMap individuals. Quantitative analysis of c-MYC expression in normal prostate tissues suggests an association between overexpression and variants in Region 1 of prostate cancer risk. Somatic c-MYC overexpression correlates with prostate cancer progression and more aggressive tumor forms, which was also a pathological variable associated with Region 1. Expression profiling analysis and modeling of transcriptional regulatory networks predicts a functional association between MYC and the prostate tumor suppressor KLF6. Analysis of MYC/Myc-driven cell transformation and tumorigenesis substantiates a model in which MYC overexpression promotes transformation by down-regulating KLF6. In this model, a feedback loop through E-cadherin down-regulation causes further transactivation of c-MYC.

Conclusion

This study proposes that variation at putative 8q24 cis-regulator(s) of transcription can significantly alter germline c-MYC expression levels and, thus, contribute to prostate cancer susceptibility by down-regulating the prostate tumor suppressor KLF6 gene.
Optimized molecular resolution of cross-contamination alerts in clinical mycobacteriology laboratories
Authors: Martín Ana , Herranz Marta , Lirola Miguel Martínez , Fernández Rosa Fernández ,   INDAL-TB group, Bouza Emilio , de Viedma Darío García
Published: February 2008

Background

The phenomenon of misdiagnosing tuberculosis (TB) by laboratory cross-contamination when culturing Mycobacterium tuberculosis (MTB) has been widely reported and it has an obvious clinical, therapeutic and social impact. The final confirmation of a cross-contamination event requires the molecular identification of the same MTB strain cultured from both the potential source of the contamination and from the false-positive candidate. The molecular tool usually applied in this context is IS6110-RFLP which takes a long time to provide an answer, usually longer than is acceptable for microbiologists and clinicians to make decisions. Our purpose in this study is to evaluate a novel PCR-based method, MIRU-VNTR as an alternative to assure a rapid and optimized analysis of cross-contamination alerts.

Results

MIRU-VNTR was prospectively compared with IS6110-RFLP for clarifying 19 alerts of false positivity from other laboratories. MIRU-VNTR highly correlated with IS6110-RFLP, reduced the response time by 27 days and clarified six alerts unresolved by RFLP. Additionally, MIRU-VNTR revealed complex situations such as contamination events involving polyclonal isolates and a false-positive case due to the simultaneous cross-contamination from two independent sources.

Conclusion

Unlike standard RFLP-based genotyping, MIRU-VNTR i) could help reduce the impact of a false positive diagnosis of TB, ii) increased the number of events that could be solved and iii) revealed the complexity of some cross-contamination events that could not be dissected by IS6110-RFLP.
Preclinical studies of Apogossypolone: a new nonpeptidic pan small-molecule inhibitor of Bcl-2, Bcl-XL and Mcl-1 proteins in Follicular Small Cleaved Cell Lymphoma model
Authors: Arnold Alan A , Aboukameel Amro , Chen Jianyong , Yang Dajun , Wang Shaomeng , Al-Katib Ayad , Mohammad Ramzi M
Published: February 2008

Elevated expression of anti-apoptotic Bcl-2 family proteins have been linked to a poor survival rate of patients with Follicular Lymphoma (FL). This prompted us to evaluate a very potent non-peptidic Small-Molecule Inhibitor (SMI) targeting Bcl-2 family proteins, Apogossypolone (ApoG2) using follicular small cleaved cell lymphoma cell line (WSU-FSCCL) and cell isolated from lymphoma patients. ApoG2 inhibited the growth of WSU-FSCCL significantly with a 50% growth inhibition of cells (IC50) of 109 nM and decreased cell number of fresh lymphoma cells. ApoG2 activated caspases-9, -3, and -8, and the cleavage of Poly (ADP-ribose) polymerase (PARP) and Apoptosis Inducing Factor (AIF). In the WSU-FSCCL-SCID xenograft model, ApoG2 showed a significant anti-lymphoma effect, with %ILS of 84% in the intravenous and 63% in intraperitoneal treated mice. These studies suggest that ApoG2 can be an effective therapeutic agent against FL.
Breast cancer stroma frequently recruits fetal derived cells during pregnancy
Authors: Dubernard Gil , Aractingi Sélim , Oster Michel , Rouzier Roman , Mathieu Marie-Christine , Uzan Serge , Khosrotehrani Kiarash
Published: February 2008

Introduction

Breast carcinomas associated with pregnancy display a high frequency of inflammatory types, multifocal lesions and lymph node metastasis. Because pregnancy results in transfer to mothers of foetal stem cells that can migrate and differentiate into various tissues, we addressed the issue of whether such cells are present in breast carcinoma associated with pregnancy.

Methods

We analyzed women presenting with such tumours who were pregnant with male foetuses using fluorescence in situ hybridization (FISH), targeting X and Y chromosomes. The foetal cell phenotype was then determined by combining FISH and immunohistochemistry with various antibodies. Statistical analysis was performed using t-test or nonparametric Wilcoxon's test.

Results

We found that foetal cells were present in nine out of 10 carcinomas, in contrast with none of four benign mammary lesions (P < 0.05). Counting foetal and maternal cells showed that the mean number of foetal cells per million maternal cells was 36 in breast cancers and 0 in control samples (P < 0.01). By combining FISH and immunolabelling, we found that foetal cells expressed mainly mesenchymal or, to a lesser degree, epithelial or endothelial markers, but never leucocytes.

Conclusion

These findings demonstrate the frequent presence of foetal derived cells essentially in tumour stroma. Given the role played by stroma in tumour proliferation, these findings raise the issue of whether foetal cell can be targeted to influence tumour behaviour.
ESR1 and EGFgenetic variation in relation to breast cancer risk and survival
Authors: Einarsdóttir Kristjana , Darabi Hatef , Li Yi , Low Yen Ling , Li Yu Qing , Bonnard Carine , Sjölander Arvid , Czene Kamila , Wedrén Sara , Liu Edison T , Hall Per , Humphreys Keith , Liu Jianjun
Published: February 2008

Introduction

Oestrogen exposure is a central factor in the development of breast cancer. Oestrogen receptor alpha (ESR1) is the main mediator of oestrogen effect in breast epithelia and has also been shown to be activated by epidermal growth factor (EGF). We sought to determine if common genetic variation in the ESR1 and EGF genes affects breast cancer risk, tumour characteristics or breast cancer survival.

Methods

We genotyped 157 single nucleotide polymorphisms (SNPs) in ESR1 and 54 SNPs in EGF in 92 Swedish controls and selected haplotype tagging SNPs (tagSNPs) that could predict both single SNP and haplotype variation in the genes with an R2 of at least 0.8. The tagSNPs were genotyped in 1,590 breast cancer cases and 1,518 controls, and their association with breast cancer risk, tumour characteristics and survival were assessed using unconditional logistic regression models, Cox proportional hazard models and haplotype analysis.

Results

The single tagSNP analysis did not reveal association evidence for breast cancer risk, tumour characteristics, or survival. A multi-locus analysis of five adjacent tagSNPs suggested a region in ESR1 (between rs3003925 and rs2144025) for association with breast cancer risk (p = 0.001), but the result did not withstand adjustment for multiple comparisons (p = 0.086). A similar region was also implicated by haplotype analyses, but its significance needs to be verified by follow-up analysis.

Conclusion

Our results do not support a strong association between common variants in the ESR1 and EGF genes and breast cancer risk, tumour characteristics or survival.
1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene (p,p'-DDE) disrupts the estrogen-androgen balance regulating the growth of hormone-dependent breast cancer cells
Authors: Aubé Michel , Larochelle Christian , Ayotte Pierre
Published: February 2008

Introduction

Estrogen and androgen signalling pathways exert opposing influences on the proliferation of mammary epithelial and hormone-dependent breast cancer cells. We previously reported that plasma concentrations of 1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene (p,p'-DDE), the main metabolite of the insecticide DDT (1,1,1-trichloro-2,2-bis [p-chlorophenyl]ethane) and a potent androgen antagonist, were associated with tumor aggressiveness in women diagnosed with breast cancer. We sought to examine the biological plausibility of this association by testing the effect of p,p'-DDE on the proliferation of CAMA-1 cells, a human breast cancer cell line that expresses the estrogen receptor alpha (ERα) and the androgen receptor (AR), in the presence of physiological concentrations of estrogens and androgens in the cell culture medium.

Methods

The proliferation of CAMA-1 cells was determined in 96-well plates following a 9-day treatment with p,p'-DDE alone (0.1 to 10 μM) or in combination with 17β-estradiol (E2) (100 pM) and dihydrotestosterone (DHT) (100, 500, or 1,000 pM). We also assessed p,p'-DDE-induced modifications in cell cycle entry and the expression of the sex-steroid-dependent genes ESR1, AR, CCND1, and TFF1 (pS2) (mRNA and/or protein).

Results

We found that treatment with p,p'-DDE induced a dose-response increase in the proliferation of CAMA-1 cells when cultivated in the presence of physiological concentrations of estrogens and androgens, but not in the absence of sex steroids in the cell culture medium. A similar effect of p,p'-DDE was noted on the proliferation of MCF7-AR1 cells, an estrogen-responsive cell line that was genetically engineered to overexpress the AR. DHT added together with E2 to the cell culture medium decreased the recruitment of CAMA-1 cells in the S phase and the expression of ESR1 and CCND1 by comparison with cells treated with E2 alone. These androgen-mediated effects were blocked with similar efficacy by p,p'-DDE and the potent antiandrogen hydroxyflutamide.

Conclusion

Our results suggest that p,p'-DDE could increase breast cancer progression by opposing the androgen signalling pathway that inhibits growth in hormone-responsive breast cancer cells. The potential role of environmental antiandrogens in breast carcinogenesis deserves further investigation.
Characterization of a subset of bone marrow-derived natural killer cells that regulates T cell activation in rats
Authors: Kheradmand Taba , Trivedi Prachi P , Wolf Norbert A , Roberts Paul C , Swanborg Robert H
Published: February 2008

We report that bone marrow-derived natural killer (BMNK) cells from DA or F344 rats inhibit PMA/ionomycin-induced T cell proliferation. These NK-regulatory cells are NKR-P1Adim, whereas a minor subpopulation is NKR-P1Abright. Only the NKR-P1Adim BMNK cells inhibit T cell proliferation. If activated with rat Con A supernatant, the NKR-P1Adim cells become NKR-P1Abright and lose the ability to inhibit T cell proliferation. In contrast to BMNK cells, all DA and F344 rat NK cells isolated from the blood, spleen, cervical, or mesenteric lymph nodes or Peyer’s patches are NKR-P1Abright and lack the ability to inhibit T cell proliferation. Inhibition of T cell proliferation correlates with significant down-regulation of CD3, suggesting that this may be the mechanism through which the NKR-P1Adim cells mediate suppression. The nitric oxide synthase inhibitor NG-monomethyl-arginine acetate-abrogated NKR-P1Adim cell inhibition of T cell proliferation. We conclude that rat bone marrow NKR-P1Adim cells represent a unique population that may play a role in maintaining immune homeostasis by regulating the clonal expansion of activated T cells.
Interaction of amyloid precursor protein with contactins and NgCAM in the retinotectal system
Authors: Osterfield Miriam , Egelund Rikke , Young Lauren M. , Flanagan John G.
Published: February 2008

The amyloid precursor protein (APP) plays a central role in Alzheimer's disease, but its actions in normal development are not well understood. Here,a tagged APP ectodomain was used to identify extracellular binding partners in developing chick brain. Prominent binding sites were seen in the olfactory bulb and on retinal axons growing into the optic tectum. Co-precipitation from these tissues and tandem mass spectrometry led to the identification of two associated proteins: contactin 4 and NgCAM. In vitro binding studies revealed direct interactions among multiple members of the APP and contactin protein families. Levels of the APP processing fragment, CTFα, were modulated by both contactin 4 and NgCAM. In the developing retinotectal system, APP,contactin 4 and NgCAM are expressed in the retina and tectum in suitable locations to interact. Functional assays revealed regulatory effects of both APP and contactin 4 on NgCAM-dependent growth of cultured retinal axons,demonstrating specific functional interactions among these proteins. These studies identify novel binding and functional interactions among proteins of the APP, contactin and L1CAM families, with general implications for mechanisms of APP action in neural development and disease.
High-speed imaging of developing heart valves reveals interplay of morphogenesis and function
Authors: Scherz Paul J. , Huisken Jan , Sahai-Hernandez Pankaj , Stainier Didier Y. R.
Published: February 2008

Knowing how mutations disrupt the interplay between atrioventricular valve(AVV) morphogenesis and function is crucial for understanding how congenital valve defects arise. Here, we use high-speed fluorescence microscopy to investigate AVV morphogenesis in zebrafish at cellular resolution. We find that valve leaflets form directly through a process of invagination, rather than first forming endocardial cushions. There are three phases of valve function in embryonic development. First, the atrioventricular canal (AVC) is closed by the mechanical action of the myocardium, rolls together and then relaxes. The growing valve leaflets serve to block the canal during the roll and, depending on the developmental stage, either expand or hang down as a leaflet to block the canal. These steps are disrupted by the subtle morphological changes that result from inhibiting ErbB-, TGFβ-or Cox2(Ptgs2)-dependent signaling. Cox2 inhibition affects valve development due to its effect on myocardial cell size and shape, which changes the morphology of the ventricle and alters valve geometry. Thus, different signaling pathways regulate distinct aspects of the behavior of individual cells during valve morphogenesis, thereby influencing specific facets of valve function.
Notochord-derived Shh concentrates in close association with the apically positioned basal body in neural target cells and forms a dynamic gradient during neural patterning
Authors: Chamberlain Chester E. , Jeong Juhee , Guo Chaoshe , Allen Benjamin L. , McMahon Andrew P.
Published: February 2008

Sonic hedgehog (Shh) ligand secreted by the notochord induces distinct ventral cell identities in the adjacent neural tube by a concentration-dependent mechanism. To study this process, we genetically engineered mice that produce bioactive, fluorescently labeled Shh from the endogenous locus. We show that Shh ligand concentrates in close association with the apically positioned basal body of neural target cells, forming a dynamic, punctate gradient in the ventral neural tube. Both ligand lipidation and target field response influence the gradient profile, but not the ability of Shh to concentrate around the basal body. Further, subcellular analysis suggests that Shh from the notochord might traffic into the neural target field by means of an apical-to-basal-oriented microtubule scaffold. This study, in which we directly observe, measure, localize and modify notochord-derived Shh ligand in the context of neural patterning, provides several new insights into mechanisms of Shh morphogen action.
Alternative promoter use in eye development: the complex role and regulation of the transcription factor MITF
Authors: Bharti Kapil , Liu Wenfang , Csermely Tamas , Bertuzzi Stefano , Arnheiter Heinz
Published: February 2008

During vertebrate eye development, the transcription factor MITF plays central roles in neuroepithelial domain specification and differentiation of the retinal pigment epithelium. MITF is not a single protein but represents a family of isoforms generated from a common gene by alternative promoter/exon use. To address the question of the role and regulation of these isoforms, we first determined their expression patterns in developing mouse eyes and analyzed the role of some of them in genetic models. We found that two isoforms, A- and J-Mitf, are present throughout development in both retina and pigment epithelium, whereas H-Mitf is detected preferentially and D-Mitf exclusively in the pigment epithelium. We further found that a genomic deletion encompassing the promoter/exon regions of H-, D- and B-Mitf leads to novel mRNA isoforms and proteins translated from internal start sites. These novel proteins lack the normal, isoform-specific N-terminal sequences and are unable to support the development of the pigment epithelium, but are capable of inducing pigmentation in the ciliary margin and the iris. Moreover, in mutants of the retinal Mitf regulator Chx10 (Vsx2),reduced cell proliferation and abnormal pigmentation of the retina are associated with a preferential upregulation of H- and D-Mitf. This retinal phenotype is corrected when H- and D-Mitf are missing in double Mitf/Chx10 mutants. The results suggest that Mitf regulation in the developing eye is isoform-selective, both temporally and spatially, and that some isoforms, including H- and D-Mitf, are more crucial than others in effecting normal retina and pigment epithelium development.
Determination of the Ionization Potentials of Security-Relevant Substances with Single Photon Ionization Mass Spectrometry Using Synchrotron Radiation
Authors: Schramm E. , Mühlberger F. , Mitschke S. , Reichardt G. , Schulte-Ladbeck R. , Pütz M. , Zimmermann R.
Published: February 2008

Several ionization potentials (IPs) of security relevant substances were determined with single photon ionization time of flight mass spectrometry (SPI-TOFMS) using monochromatized synchrotron radiation from the “Berliner Elektronenspeicherring-Gesellschaft für Synchrotronstrahlung” (BESSY). In detail, the IPs of nine explosives and related compounds, seven narcotics and narcotics precursors, and one chemical warfare agent (CWA) precursor were determined, whereas six IPs already known from the literature were verified correctly. From seven other substances, including one CWA precursor, the IP could not be determined as the molecule ion peak could not be detected. For these substances the appearance energy (AE) of a main fragment was determined. The analyzed security-relevant substances showed IPs significantly below the IPs of common matrix compounds such as nitrogen and oxygen. Therefore, it is possible to find photon energies in between, whereby the molecules of interest can be detected with SPI in very low concentrations due to the shielding of the matrix. All determined IPs except the one of the explosive EGDN were below 10.5 eV. Hence, laser-generated 118 nm photons can be applied for detecting almost all security-relevant substances by, e.g., SPI-TOFMS.
Surface-Enhanced Raman Spectroscopy Studies of Surfactant Adsorption to a Hydrophobic Interface
Authors: Olson Lydia G. , Harris Joel M.
Published: February 2008

Surface-enhanced Raman spectroscopy is used to investigate the kinetics of adsorption of the cationic surfactant cetylpyridinium chloride (CPC) to hydrophobic surfaces from water. A hydrophobic surface, with stable and reproducible SERS activity, is produced by binding gold colloids to an amine-terminated glass slide and then modifying this surface with octadecyltrimethoxysilane. In situ SERS-detected adsorption of CPC from aqueous solution is found to follow a Frumkin isotherm. Interactions between the charged head groups could be detected in frequency shifts in the symmetric ring breathing mode, consistent with an interfacial surfactant environment similar to a CPC micelle. Rates of surfactant adsorption were determined by time-resolved SERS measurements and were found to be much slower than the diffusion-controlled limit, indicating a significant kinetic barrier to adsorption. Desorption kinetics were heterogeneous, consistent with the spectroscopic results. Alkylsilane-modified gold colloids were shown to be useful substrates for investigating amphiphile adsorption from aqueous solutions to hydrophobic surfaces, where the adsorption kinetics could also be used to determine analyte concentrations in solution.
Discriminant Analysis of Fused Positive and Negative Ion Mobility Spectra Using Multivariate Self-Modeling Mixture Analysis and Neural Networks
Authors: Chen Ping , Harrington Peter B.
Published: February 2008

A new method coupling multivariate self-modeling mixture analysis and pattern recognition has been developed to identify toxic industrial chemicals using fused positive and negative ion mobility spectra (dual scan spectra). A Smiths lightweight chemical detector (LCD), which can measure positive and negative ion mobility spectra simultaneously, was used to acquire the data. Simple-to-use interactive self-modeling mixture analysis (SIMPLISMA) was used to separate the analytical peaks in the ion mobility spectra from the background reactant ion peaks (RIP). The SIMPLSIMA analytical components of the positive and negative ion peaks were combined together in a butterfly representation (i.e., negative spectra are reported with negative drift times and reflected with respect to the ordinate and juxtaposed with the positive ion mobility spectra). Temperature constrained cascade-correlation neural network (TCCCN) models were built to classify the toxic industrial chemicals. Seven common toxic industrial chemicals were used in this project to evaluate the performance of the algorithm. Ten bootstrapped Latin partitions demonstrated that the classification of neural networks using the SIMPLISMA components was statistically better than neural network models trained with fused ion mobility spectra (IMS).
Fabrication and Elimination of PTAA/P4VP Layer-By-Layer Films
Authors: Jiang Yan , Wu Peiyi
Published: February 2008

Layer-by-layer (LBL) ultra-thin films have been assembled by alternate adsorption of poly(3-thiophene acetic acid) (PTAA) and poly(4-vinylpyridine) (P4VP) on planar quartz slides via hydrogen-bonding interaction. Subsequently, the multilayers can be controllably removed by changing the pH values of the aqueous solutions used for film immersion. Our present study is an attempt to reveal the mechanisms of the multilayer film with two-dimensional (2D) ultraviolet-visible (UV-vis) correlation spectroscopy. UV-vis spectroscopy is primarily employed here to monitor the buildup and removal of the ultra-thin films. 2D correlation analysis is performed on the basis of the corresponding spectra for further studies. The morphology of the multilayer film is characterized by atomic force microscopy (AFM). When eliminated in alkaline and acidic aqueous solutions, the polymers in the films show diverse phenomena mainly due to the different extents of dissociation of PTAA and protonation of P4VP at different pH values. In alkaline solution, the elimination of PTAA takes place before P4VP, while in acid solution, the removal of these two polymers adopts a reverse order.
Advantages of Soft versus Hard Constraints in Self-Modeling Curve Resolution Problems. Penalty Alternating Least Squares (P-ALS) Extension to Multi-Way Problems
Authors: Richards Selena , Miller Robert , Gemperline Paul
Published: February 2008

An extension to the penalty alternating least squares (P-ALS) method, called multi-way penalty alternating least squares (NWAY P-ALS), is presented. Optionally, hard constraints (no deviation from predefined constraints) or soft constraints (small deviations from predefined constraints) were applied through the application of a row-wise penalty least squares function. NWAY P-ALS was applied to the multi-batch near-infrared (NIR) data acquired from the base catalyzed esterification reaction of acetic anhydride in order to resolve the concentration and spectral profiles of 1-butanol with the reaction constituents. Application of the NWAY P-ALS approach resulted in the reduction of the number of active constraints at the solution point, while the batch column-wise augmentation allowed hard constraints in the spectral profiles and resolved rank deficiency problems of the measurement matrix. The results were compared with the multi-way multivariate curve resolution (MCR)-ALS results using hard and soft constraints to determine whether any advantages had been gained through using the weighted least squares function of NWAY P-ALS over the MCR-ALS resolution.
Excess Infrared Absorption Spectroscopy and its Applications in the Studies of Hydrogen Bonds in Alcohol-Containing Binary Mixtures
Authors: Li Qingzhong , Wang Nannan , Zhou Qun , Sun Suqin , Yu Zhiwu
Published: February 2008

Excess infrared (IR) absorption spectroscopy, a new concept brought forward by applying the idea of excess thermodynamic functions to infrared spectroscopy, is shown to be a potential method to study hydrogen bonds. It can be applied to enhance spectral resolution of complexed IR bands, to evaluate nonideality of liquid mixtures, and to estimate selective molecular interactions. The sign of the excess infrared absorption coefficient is also of importance in providing information on molecular interactions. The results demonstrate that excess infrared absorption spectroscopy can unveil new information on hydrogen bonding in condensed phases.
Swelling of larch wood in organic liquids
Authors: Loskutov Sergei R. , Aniskina Antonina A.
Published: February 2008

The swelling of larch wood in 1-butanol, dimethyl sulfoxide, N,N-dimethyl formamide, ethylene glycol, ethanol, methyl cellosolve, 1-propanol and toluene was investigated at room temperature. The volumetric, tangential and radial swelling completion was lagging behind the liquid absorption process. The kinetic indices of swelling of larch wood were determined based on the equation of Kolmogorov-Erofeev. The volumetric swelling was related to molecular mass, molar volume, dielectric permittivity and integral heat of wood wetting. The anisotropy of wood swelling was characterized by the ratio of equilibrium tangential swelling to radial swelling (α
t,/α
r). It was demonstrated that α
t,/α
r is related to the dipole component of Hansen's parameter and cannot exceed the value 3.
Effects of thermomechanical refining conditions on the morphology and thermal properties of wheat straw fibre
Authors: Pan Ming-Zhu , Zhou Ding-Guo , Mei Chang-Tong , Deng James , Wang Xiang-Ming , Zhang Tony S.Y.
Published: February 2008

Wheat straw fibre is prepared by a thermomechanical (TM) refining system. This study investigated the effects of refining steam pressure (4, 6, 8 and 10 bar) and refiner speed (2500 and 3000 rpm) on the morphology and thermal properties of the resulting fibres. After TM refining, the fibres exhibited more surface irregularities and heterogeneities as well as decreased fibre length. The fine content decreased with increasing steam pressure, but the aspect ratio increased. The findings show that higher steam pressure (8 bar) results in more effective wheat straw refining. Refining lowers the pH. Thermogravimetric analysis showed that TM refining does not influence the thermal properties of wheat straw fibres. Weight loss has to be taken into account upon exposure to temperatures around 170°C. The silica content of the fibres was significantly reduced through refining.
New Slurry Displacement Method for Reconstitution of Highly Gap-Graded Specimens for Laboratory Element Testing
Authors: Khalili Ali , Wijewickreme Dharma
Published: February 2008

A new “slurry displacement” method was developed for reconstitution of cylindrical specimens of highly gap-graded soils for laboratory element testing. The method stems from a need to conduct laboratory element tests on mixtures of waste rock and tailings with specific relevance to the development of new technology and material science for mining industry. The slurry displacement method allows preparing uniform/homogeneous specimens of highly gap-graded materials in a saturated condition, thus overcoming the difficulties in the use of currently available specimen preparation techniques. The suitability of the technique to replicate specimens is demonstrated by the repeatable test results obtained from shear testing of identical specimens prepared using the method.
Formulation Performance Improvements with Blends of Alkyl Naphthalene Sulfonate Condensates Plus Lignosulfonates When Compared to Lignosulfonates Alone
Authors: Alexander Mark W.
Published: February 2008

Comparative data were generated on lignosulfonates, dry blends, and co-processed blends of ANSCs plus lignosulfonates in a series of pesticide formulations. There was an unexpected improvement in the performance of certain formulations when the co-processed blends were compared to the dry blends of the dispersants.
Thickness Gaging of Thin Plates by Multi-Peak Frequency Decomposition of Lamb Wave Signals
Authors: Edalati K. , Edalati A. , Kermani A.
Published: February 2008

In the present work ultrasonic Lamb wave testing has been applied for thickness gaging of thin aluminum plates with 2, 3, and 4-mm thickness. Angle probes operated in pulse-echo arrangement with 0.98 MHz central frequency and 7°, 12°, and 20° incident angles were utilized for investigations. High order modes (A1, S1, A2, and S2) were selected and evaluated for measurements and a fast Fourier transform was utilized for frequency decomposition. The variation with thickness and frequency of the phase velocity was the basis of measurement. Two methods were proposed for thickness gaging: (1) a probe with 6000–8000 m/s phase velocity and one or two other probes with higher than 10 000 m/s phase velocity were utilized simultaneously to inspect each test area and the peak frequency with the highest amplitude excited by each probe was evaluated, and (2) a single probe was utilized and all visible peak frequencies were evaluated. These methods overcome the limitations of the previous research, which applied a peak frequency shift method for corrosion monitoring of plates only for a known mode and known initial thickness and low thickness reductions. The second method is more practical and accurate and has potential for on-line automatic thickness gaging of rolled plates.
Time scale embedding theorem and coercivity of quadratic functionals
Authors: Hilscher Roman , Zeidan Vera
Published: February 2008

In this paper we study the relation between the coercivity and positivity of a time scale quadratic functional
Remark on uniqueness of weak solutions to the Navier–Stokes equations
Authors: Gala Sadek , Benbernou Samia
Published: February 2008

Consider the Navier–Stokes equations with the initial data a ∈
Entire functions sharing a polynomial with their derivatives and normal families
Authors: Grahl Jürgen , Meng Chao
Published: February 2008

Let

is constant. Furthermore, we prove the corresponding normality criterion.
Asymptotic behavior of the solutions of the Dirichlet problem for the Laplace operator in a domain with a small hole. A functional analytic approach
Authors: Lanza de Cristoforis Massimo
Published: February 2008

We consider a hypersurface in R