bluuebunny/crossref_metadata_2025 huggingface dataset:
Wear Mechanism of Glass Fiber Reinforced Epoxy Composites Under Dry Sliding Using Fuzzy Clustering Technique
Authors: Srinivasan V. , Asaithambi B. , Ganesan G. , Karthikeyan R. , Palanikumar K.
Published: July 2008

Polymers and polymer composites are steadily gaining ground over metals in the field of engineering applications in tribology. In the present study, the friction and wear behavior of glass fiberreinforced epoxy composites against stainless steel under dry sliding conditions has been comparatively evaluated on a friction and wear tester at different sliding velocities ranging from 0.6 to 2.5 m/s and normal force of 9.81 to 19.62 N. Besides, conventional weighing, determination of coefficient of friction (µ), temperature, wear rate, and examination of the worn surface features were taken by scanning electron microscope. Fuzzy clustering technique has been used to plot the wear rate and wear transition map. The tribological behavior of glass fiber reinforced epoxy composites, the wear mechanisms and its relation with a wear transition map are discussed in detail.
Jute Reinforced Polypropylene Composite: Effect of Surface Pretreatment by Photocuring with Acrylic Monomers
Authors: Rahman S.M.M.A. , Mustafa A.I. , Khan Mubarak A.
Published: July 2008

Jute fiber (hessian cloth) reinforced polypropylene (PP) composites were prepared by compression molding. The composite fabrication temperature, pressure and time were 190°C, 4 tons and 5 min, respectively. The jute content, in the composites was studied over mechanical properties and it was observed that the highest TS (70 MPa), BS (75 MPa) and bending-E-modulus (2.35 GPa) were produced by 60% jute content, but Young's modulus was found to be the highest (1.95 GPa) at 38% jute content. To further improve the mechanical properties and interfacial adhesion behavior between jute and polypropylene, hessian cloth was pretreated with acrylic monomers, e.g., 1,4-butanediol diacrylate (BDDA), ethyl hexyl acrylate (EHA) and trypropylene glycol diacrylate (TPGDA) at different concentrations using 2% photoinitiator (Darocur-1116) under UV radiation of various intensities. Among all the monomers BDDA showed the best performance. The highest TS (90 MPa), BS (95 MPa), Young's modulus (2.2 GPa) and bending-E-modulus (3.2 GPa) of the composite were obtained when hessian cloth was cured by soaking it for 10 min in a solution containing 3% BDDA, 2% photoinitiator in methanol, followed by exposure to six passes of UV radiation. Under this condition polymer loading (PL) of photocured hessian cloth was 14%.
Production of Tribological Composites by Recycling Dust of Friction Products
Authors: Lucignano Carmine , Quadrini Fabrizio , Tagliaferri Vincenzo
Published: July 2008

Polymeric matrix composites were prepared by mixing a tribological dust in a polyester resin. The dust resulted from the fabrication process of friction products and was initially destined for disposal. Composite specimens were fabricated with different dust content (up to 70wt%) and cured in an oven at 80°C for 30min. Flexure tests and dynamic mechanical analysis (DMA) were carried out together with pin-on-disc tests to quantify mechanical and tribological performances. Flexural modulus and strength generally increased by increasing the filler content as well as the friction coefficient. At the highest values (60—70 wt%), mechanical and tribological properties were damaged by the dust clustering during mixing.
Application of Vibrating Beam Method to Determine Dynamic Properties of Flexible Adhesives
Authors: Kadioglu Ferhat , Adams Robert
Published: July 2008

Nowadays, ductile adhesives are entering the arena of structural applications due to their high strains to failure that is able to tolerate possible stress—strain concentrations, and due to their high damping performance, which is useful for energy dissipation. In this article, dynamic properties of such an adhesive are investigated using a vibrating beam technique with free—free end conditions. For the measurements of flexural modulus and damping values of the adhesive, the free layer beam configuration with different layer thicknesses was used. It is shown that the technique is able to give the consistent results and the data can be used for design purposes. The results suggest that the dynamic properties of the adhesive are frequency dependent at room temperature, which means the adhesive has a viscoelastic behavior.
LRFD Approach for FRP-Reinforced Thermoplastic Beams
Authors: Razzaq Zia , Coskun Hilmi , Li Xiaojing , Beach Robert , Prabhakaran Ram
Published: July 2008

Thermoplastic beams are currently being used primarily in marine and waterfront applications, and can be used in bridges and buildings. A summary is presented of an experimental and theoretical study of the flexural behavior of a commercially available thermoplastic beam known as Seatimber with simple supports and subjected to a gradually increasing midspan concentrated load. Theoretical predictions are based on a non-linear moment-curvature analysis coupled with a central finite-difference scheme. Simplified criteria for a load and resistance factor design (LRFD) approach is outlined and its use demonstrated through analysis and design examples.
Mechanical and Wear Characterization of GF Reinforced Vinyl Ester Resin Composites with Different Co-Monomers
Authors: Chauhan S. , Kumar Anoop , Patnaik Amar , Satapathy Alok , Singh I.
Published: July 2008

This article reports the mechanical characterization and sliding wear behavior of glass fiber-reinforced vinyl ester resins of varying acid values, based on epoxy-novalocs in the presence of three different comonomers (styrene, methyl acrylate and butyl acrylate) as reactive diluents. It presents a special account of the optimization of fabrication techniques of glass fiber-reinforced vinyl ester resin composites. It outlines optimum reaction conditions such as temperature, time, monomer type and initiator concentration. The experimental plan consisted of preparation of vinyl ester resin followed by the composite samples. Mechanical characterization was done and a comparison was made between the different samples. It was found that these composites have fairly good tensile and flexural properties. The composites with styrene and butyl acrylate as co-monomers had similar tensile strength which was higher than that of the composite with methyl acrylate. Hardness values of the three composites were almost the same without any significant effect of the comonomer type. Volumetric wear rate was estimated for these samples under various test conditions. A steady wear rate regime after certain amount of sliding was observed all the three cases.
Urban Elementary School Teachers' Perspectives Regarding Collaborative Teaching Practices
Authors: Damore Sharon J. , Murray Christopher
Published: July 2008

Collaborative teaching has grown in popularity as students with disabilities have been increasingly moved to general education classrooms. Despite the growth of these models, little empirical evidence exists regarding the effectiveness of these practices. In this investigation, general and special education teachers ( N = 118) from 20 urban elementary schools were surveyed regarding their perceptions of collaborative teaching. The survey instrument elicited teacher perceptions about collaboration, their views regarding inclusion, and what is needed to ensure effective collaborative teaching. Findings indicate that 92% of respondents thought that collaboration was occurring in their school but that only 57% reported use of the practices in their own classrooms. Respondents valued inclusive practices, although special educators had more positive perceptions than did general educators. The interpersonal and structural factors valued by these teachers included team processes, positive attitudes, resources, professional development, leadership, university training, accountability, shared responsibility, and communication.
Engaging Mexican Immigrant Families in Language and Literacy Interventions
Authors: Kummerer Sharon E. , Lopez-Reyna Norma A.
Published: July 2008

This article describes the experiences of three Mexican immigrant mothers and their young children who were participating in early intervention speech-language therapy. Mother interviews, children’s therapy files, observation field notes, and parent journals contributed to the construction of instrumental case studies. Highlighting the potential for collaborative relationships, the authors describe how mothers’ concerns, understandings, and participation changed across intervention and how the clinician and mothers developed shared goals and informed one another. The case studies portray mothers’ beliefs about language and literacy development, perceptions of their children’s abilities, and the mother—child relationship around speech-language therapy. Based on these beliefs and perceptions, avenues for the increased engagement of Mexican immigrant families in their children’s early language and literacy opportunities are suggested.
Congress, Crime, and Budgetary Responsiveness
Authors: Marion Nancy E. , Oliver Willard M.
Published: July 2008

In 1980, Caldeira and Cowart theorized that Congress has been responsive in its budgetary responsibilities to the rise in official crime rates. Their findings based on their study from 1935 to 1975 supported the theory that Congress was engaged in substantive policy making. This article theorizes that Caldeira and Cowarts' findings are no longer true and that criminal justice policy making has become more symbolic in recent years. Hence, budgetary appropriations should no longer be responsive to the rise and fall in official crime rates. Drawing on the theory of symbolic politics, which posits that political acts are viewed as symbols conveying a political meaning that are an end unto themselves, this study replicates and updates the work of Caldeira and Cowart. The study finds support for the theory of symbolic politics and suggests that Congressional involvement in crime policy, beginning in the early 1970s, has become even more symbolic.
Turning Around Failing Schools
Authors: Murphy Joseph
Published: July 2008

In this article, the author reviews research from the organizational sciences to develop turnaround policy guidelines that may prove useful for policy makers and educators. The approach is an integrative review of the literature. The author employs a comprehensive process to unpack and make sense of the turnaround literature from the organizational sciences. Strategies appropriate for document analysis and interview data are employed. Insights are captured from the five major research pathways for studying organizational turnaround. Research findings are blended into three policy dimensions, namely, leadership, efficiency, and focus. It is argued that the literature on turning around failing organizations in sectors outside of education provides potential blueprints for recovery activity in failing schools. This is the first systematic effort to mine research in the corporate, not-for-profit, and public sectors to develop policy insights for shaping efforts to turn around failing schools.
When worlds collide: Developing game-design partnerships in universities
Authors: Lynch Martin A. , Tunstall Richard J.
Published: July 2008

A growing body of evidence suggests that relevant, well-designed simulations can make a valuable contribution to students' experiences in training and education and go some way toward meeting the expectations of students who have grown up with immersive, computer-mediated games. Within universities, many barriers exist that may prevent the effective development of this work, in part because of the nature of the traditional roles of both academics and developers who undertake these activities. Through a discussion of the experiences of working within a successful cross-functional team, the authors discuss the practice of developing an innovative eLearning simulation tool for an undergraduate course and how the challenges of combining the developer and educationalist roles were overcome. By synthesizing theories in educational philosophy and game design processes, a conceptual framework for ensuring quality in creative education projects is outlined that may be applied to the development of eLearning and adaptive game projects.
Understanding Racial/Ethnic Disparities in Youth Mental Health Services
Authors: Gudiño Omar G. , Lau Anna S. , Yeh May , McCabe Kristen M. , Hough Richard L.
Published: July 2008

The authors examined racial/ethnic disparities in mental health service use based on problem type (internalizing/externalizing). A diverse sample of youth in contact with public sectors of care and their families provided reports of youth's symptoms and functional impairment during an initial interview. Specialty and school-based mental health service use during the subsequent 2 years was assessed prospectively. Greater disparities in mental health service receipt were evident for internalizing problems, with non-Hispanic White youth more likely to receive services in response to internalizing symptoms than minority youth. Fewer disparities in rates of unmet need emerged for externalizing problems, but minority youth were more likely to have need for externalizing problems met and African American youth were particularly likely to receive services in response to such problems. Findings highlight the importance of considering problem type when examining racial disparities in mental health services and underscore concerns about the responsiveness of mental health services for minority youth with internalizing disorders.
Depression Among Alumni of Foster Care
Authors: White Catherine Roller , O'Brien Kirk , Pecora Peter J. , English Diana , Williams Jason R. , Phillips Chereese M.
Published: July 2008

The Northwest Foster Care Alumni Study examined the relation between experiences in foster care and depression among young adults who spent at least a year in foster care as adolescents. Results indicate that preparation for leaving foster care, nurturing supports from the foster family, school stability, access to tutoring, access to therapeutic service and support, and a shorter and more stable placement history were associated with a lower probability of depression in young adulthood. Results provide evidence that suggest ways to improve practice to decrease rates of depression among alumni of care.
Can Technology and the Media Help Reduce Dysfunctional Parenting and Increase Engagement With Preventative Parenting Interventions?
Authors: Calam Rachel , Sanders Matthew R. , Miller Chloe , Sadhnani Vaneeta , Carmont Sue-Ann
Published: July 2008

In an evaluation of the television series “Driving Mum and Dad Mad,” 723 families participated and were randomly assigned to either a standard or technology enhanced viewing condition (included additional Web-support). Parents in both conditions reported significant improvements from pre- to postintervention in their child's behavior, dysfunctional parenting, parental anger, depression, and self-efficacy. Short-term improvements were maintained at 6-months follow-up. Regressions identified predictors of program outcomes and level of involvement. Parents who watched the entire series had more severe problems at preintervention and high sociodemographic risk than parents who did not watch the entire series. Few sociodemographic, child, or parent variables assessed at preintervention predicted program outcomes or program engagement, suggesting that a wide range of parents from diverse socioeconomic status benefited from the program. Media interventions depicting evidence-based parenting programs may be a useful means of reaching hard to engage families in population-level child maltreatment prevention programs.
Toward a Unifying Model of Identification With Groups: Integrating Theoretical Perspectives
Authors: Roccas Sonia , Sagiv Lilach , Schwartz Shalom , Halevy Nir , Eidelson Roy
Published: July 2008

Building on the contributions of diverse theoretical approaches, the authors present a multidimensional model of group identification. Integrating conceptions from the social identity perspective with those from research on individualism—collectivism, nationalism— patriotism, and identification with organizations, we propose four conceptually distinct modes of identification: importance (how much I view the group as part of who I am), commitment (how much I want to benefit the group), superiority (how much I view my group as superior to other groups), and deference (how much I honor, revere, and submit to the group's norms, symbols, and leaders). We present an instrument for assessing the four modes of identification and review initial empirical findings that validate the proposed model and show its utility in understanding antecedents and consequences of identification.
Personality and Prejudice: A Meta-Analysis and Theoretical Review
Authors: Sibley Chris G. , Duckitt John
Published: July 2008

Despite a substantial literature examining personality, prejudice, and related constructs such as Right-Wing Authoritarianism (RWA) and Social Dominance Orientation (SDO), there have been no systematic reviews in this area. The authors reviewed and meta-analyzed 71 studies (N = 22,068 participants) investigating relationships between Big Five dimensions of personality, RWA, SDO, and prejudice. RWA was predicted by low Openness to Experience but also Conscientiousness, whereas SDO was predicted by low Agreeableness and also weakly by low Openness to Experience. Consistent with a dual-process motivational model of ideology and prejudice, the effects of Agreeableness on prejudice were fully mediated by SDO, and those of Openness to Experience were largely mediated by RWA. Finally, the effects of Agreeableness and Openness to Experience were robust and consistent across samples, although subtle moderating factors were identified, including differences in personality inventory (NEO Personality Inventory—Revised vs. Big Five Inventory), differences across prejudice domain, and cross-cultural differences in Conscientiousness and Neuroticism. Implications for the study of personality and prejudice are discussed.
The Neglected Science and Art of Quasi-Experimentation
Authors: Grant Adam M. , Wall Toby D.
Published: July 2008

Although quasi-experiments can facilitate causal inferences by combining good internal validity with high external validity, organizational scholars underutilize them. In this article, the authors aim to encourage the novel use of quasi-experimentation by identifying five of its key benefits: (a) strengthening causal inference when random assignment and controlled manipulation are not possible or ethical; (b) building better theories of time and temporal progression; (c) minimizing ethical dilemmas of harm, inequity, paternalism, and deception; (d) facilitating collaboration with practitioners; and (e) using context to explain conflicting findings. We offer advice and illustrative examples to guide future research, and provide recommendations for gaining access to organizations to open doors for collaborating on quasi-experiments.
Preliminary Validation of the Implementation Phases Inventory for Assessing Fidelity of Schoolwide Positive Behavior Supports
Authors: Bradshaw Catherine P. , Debnam Katrina , Koth Christine W. , Leaf Philip
Published: July 2008

Schoolwide positive behavioral interventions and supports (SWPBIS) are becoming increasingly popular with schools across the country to help create safer learning environments for students. An important aspect of SWPBIS is the ongoing monitoring and evaluation of implementation fidelity. Although a few measures have been created to assess the degree to which schools are implementing the key aspects of SWPBIS, there remains a need for a tool to categorize a school's overall phase of implementation and document the schools' progression toward sustainability of SWPBIS. The present study examines the reliability and validity of the Implementation Phases Inventory (IPI), a new measure of SWPBIS implementation fidelity. The findings indicate that the IPI is an internally consistent measure with adequate test—retest reliability, interrater reliability, and concurrent validity. These findings provide preliminary evidence that supports the use of the IPI to assess phase of SWPBIS implementation.
Myc regulates aggresome formation, the induction of Noxa, and apoptosis in response to the combination of bortezomib and SAHA
Authors: Nawrocki Steffan T. , Carew Jennifer S. , Maclean Kirsteen H. , Courage James F. , Huang Peng , Houghton Janet A. , Cleveland John L. , Giles Francis J. , McConkey David J.
Published: July 2008

The histone deacetylase inhibitor SAHA enhances cell death stimulated by the proteasome inhibitor bortezomib (BZ) by disrupting BZ-induced aggresome formation. Here we report that Myc regulates the sensitivity of multiple myeloma (MM) cells to BZ + SAHA–induced cell death. In MM cells, Myc expression directly correlated with intracellular ER content, protein synthesis rates, the percentage of aggresome-positive cells, and the sensitivity to BZ + SAHA–induced cell death. Accordingly, Myc knockdown markedly reduced the sensitivity of MM cells to BZ + SAHA–mediated apoptosis. Furthermore, activation of Myc was sufficient to provoke aggresome formation and thus sensitivity to BZ + SAHA, and these responses required de novo protein synthesis. BZ + SAHA–mediated stimulation of apoptosis includes the induction of the proapoptotic BH3-only protein Noxa as well as endoplasmic reticular stress, a disruption of calcium homeostasis, and activation of capase-4. Finally, knockdown studies demonstrated that both caspase-4 and Noxa play significant roles in Myc-driven sensitivity to BZ + SAHA–induced apoptosis. Collectively, our results establish a mechanistic link between Myc activity, regulation of protein synthesis, increases in HDAC6 expression and aggresome formation, induction of Noxa, and sensitivity to BZ + SAHA–induced apoptosis. These data suggest that MM patients with elevated Myc activity may be particularly sensitive to the BZ + SAHA combination.
Hematopoiesis is not clonal in healthy elderly women
Authors: Swierczek Sabina I. , Agarwal Neeraj , Nussenzveig Roberto H. , Rothstein Gerald , Wilson Andrew , Artz Andrew , Prchal Josef T.
Published: July 2008

Clonality assays, based on X-chromosome inactivation, discriminate active from inactive alleles. Skewing of X-chromosome allelic usage, based on preferential methylation of one of the HUMARA alleles, was reported as evidence of clonal hematopoiesis in approximately 30% of elderly women. Using a quantitative, transcriptionally based clonality assay, we reported X-chromosome–transcribed allelic ratio in blood cells of healthy women consistent with random X-inactivation of 8 embryonic hematopoietic stem cells. Furthermore, we did not detect clonal hematopoiesis in more than 200 healthy nonelderly women. In view of the susceptibility of aging hematopoietic stem cells to epigenetic dysregulation, we reinvestigated the issue of clonality in elderly women. Forty healthy women (ages 65-92 years; mean, 81.3 years) were tested by a novel, quantitative polymerase chain reaction (qPCR) transcriptional clonality assay. We did not detect clonal hematopoiesis in any of the tested subjects. We also tested DNA from the same granulocyte samples using the methylation-based HUMARA assay, and confirmed previous reports of approximately 30% extensively skewed or monoallelic methylation, in agreement with likely age-related deregulated methylation of the HUMARA gene locus. We conclude that the transcriptionally based X-chromosome clonality assays are suitable for evaluation of clonal hematopoiesis in elderly women.
p120-Catenin regulates leukocyte transmigration through an effect on VE-cadherin phosphorylation
Authors: Alcaide Pilar , Newton Gail , Auerbach Scott , Sehrawat Seema , Mayadas Tanya N. , Golan David E. , Yacono Patrick , Vincent Peter , Kowalczyk Andrew , Luscinskas Francis W.
Published: July 2008

Vascular endothelial–cadherin (VE-cad) is localized to adherens junctions at endothelial cell borders and forms a complex with α-, β-, γ-, and p120-catenins (p120). We previously showed that the VE-cad complex disassociates to form short-lived “gaps” during leukocyte transendothelial migration (TEM); however, whether these gaps are required for leukocyte TEM is not clear. Recently p120 has been shown to control VE-cad surface expression through endocytosis. We hypothesized that p120 regulates VE-cad surface expression, which would in turn have functional consequences for leukocyte transmigration. Here we show that endothelial cells transduced with an adenovirus expressing p120GFP fusion protein significantly increase VE-cad expression. Moreover, endothelial junctions with high p120GFP expression largely prevent VE-cad gap formation and neutrophil leukocyte TEM; if TEM occurs, the length of time required is prolonged. We find no evidence that VE-cad endocytosis plays a role in VE-cad gap formation and instead show that this process is regulated by changes in VE-cad phosphorylation. In fact, a nonphosphorylatable VE-cad mutant prevented TEM. In summary, our studies provide compelling evidence that VE-cad gap formation is required for leukocyte transmigration and identify p120 as a critical intracellular mediator of this process through its regulation of VE-cad expression at junctions.
Parasitization by the wasp Eretmocerus mundus induces transcription of genes related to immune response and symbiotic bacteria proliferation in the whitefly Bemisia tabaci
Authors: Mahadav Assaf , Gerling Dan , Gottlieb Yuval , Czosnek Henryk , Ghanim Murad
Published: July 2008

Background

The whitefly Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae), and the viruses it transmits, are a major constraint to growing vegetable crops worldwide. Although the whitefly is often controlled using chemical pesticides, biological control agents constitute an important component in integrated pest management programs, especially in protected agriculture. One of these agents is the wasp Eretmocerus mundus (Mercet) (Hymenoptera: Aphelinidae). E. mundus lays its egg on the leaf underneath the second-third instar nymph of B. tabaci. First instars of the wasp hatch and penetrate the whitefly nymphs. Initiation of parasitization induces the host to form a capsule composed of epidermal cells around the parasitoid. The physiological and molecular processes underlying B. tabaci-E. mundus interactions have never been investigated.

Results

We used a cDNA microarray containing 6,000 expressed sequence tags (ESTs) from the whitefly genome to study the parasitoid-whitefly interaction. We compared RNA samples collected at two time points of the parasitization process: when the parasitoid first instar starts the penetration process and once it has fully penetrated the host. The results clearly indicated that genes known to be part of the defense pathways described in other insects are also involved in the response of B. tabaci to parasitization by E. mundus. Some of these responses included repression of a serine protease inhibitor (serpin) and induction of a melanization cascade. A second set of genes that responded strongly to parasitization were bacterial, encoded by whitefly symbionts. Quantitative real-time PCR and FISH analyses showed that proliferation of Rickettsia, a facultative secondary symbiont, is strongly induced upon initiation of the parasitization process, a result that supported previous reports suggesting that endosymbionts might be involved in the insect host's resistance to various environmental stresses.

Conclusion

This is the first study to examine the transcriptional response of a hemipteran insect to attack by a biological control agent (hymenopterous parasitoid), using a new genomic approach developed for this insect pest. The defense response in B. tabaci involves genes related to the immune response as described in model organisms such as Drosophila melanogaster. Moreover, endosymbionts of B. tabaci appear to play a role in the response to parasitization, as supported by previously published results from aphids.
Successful elimination of non-neural cells and unachievable elimination of glial cells by means of commonly used cell culture manipulations during differentiation of GFAP and SOX2 positive neural progenitors (NHA) to neuronal cells
Authors: Witusik Monika , Piaskowski Sylwester , Hulas-Bigoszewska Krystyna , Zakrzewska Magdalena , Gresner Sylwia M , Azizi S Ausim , Krynska Barbara , Liberski Pawel P , Rieske Piotr
Published: July 2008

Background

Although extensive research has been performed to control differentiation of neural stem cells – still, the response of those cells to diverse cell culture conditions often appears to be random and difficult to predict. To this end, we strived to obtain stabilized protocol of NHA cells differentiation – allowing for an increase in percentage yield of neuronal cells.

Results

Uncommitted GFAP and SOX2 positive neural progenitors – so-called, Normal Human Astrocytes (NHA) were differentiated in different environmental conditions to: only neural cells consisted of neuronal [MAP2+, GFAP-] and glial [GFAP+, MAP2-] population, non-neural cells [CD44+, VIMENTIN+, FIBRONECTIN+, MAP2-, GFAP-, S100β-, SOX2-], or mixture of neural and non-neural cells.

In spite of successfully increasing the percentage yield of glial and neuronal vs. non-neural cells by means of environmental changes, we were not able to increase significantly the percentage of neuronal (GABA-ergic and catecholaminergic) over glial cells under several different cell culture testing conditions. Supplementing serum-free medium with several growth factors (SHH, bFGF, GDNF) did not radically change the ratio between neuronal and glial cells – i.e., 1,1:1 in medium without growth factors and 1,4:1 in medium with GDNF, respectively.

Conclusion

We suggest that biotechnologists attempting to enrich in vitro neural cell cultures in one type of cells – such as that required for transplantology purposes, should consider the strong limiting influence of intrinsic factors upon extracellular factors commonly tested in cell culture conditions.
The impact of generic-only drug benefits on patients' use of inhaled corticosteroids in a Medicare population with asthma
Authors: Fung Vicki , Tager Ira B , Brand Richard , Newhouse Joseph P , Hsu John
Published: July 2008

Background

Patients face increasing insurance restrictions on prescription drugs, including generic-only coverage. There are no generic inhaled corticosteroids (ICS), which are a mainstay of asthma therapy, and patients pay the full price for these drugs under generic-only policies. We examined changes in ICS use following the introduction of generic-only coverage in a Medicare Advantage population from 2003–2004.

Methods

Subjects were age 65+, with asthma, prior ICS use, and no chronic obstructive pulmonary disorder (n = 1,802). In 2004, 74.0% switched from having a $30 brand-copayment plan to a generic-only coverage plan (restricted coverage); 26% had $15–25 brand copayments in 2003–2004 (unrestricted coverage). Using linear difference-in-difference models, we examined annual changes in ICS use (measured by days-of-supply dispensed). There was a lower-cost ICS available within the study setting and we also examined changes in drug choice (higher- vs. lower-cost ICS). In multivariable models we adjusted for socio-demographic, clinical, and asthma characteristics.

Results

In 2003 subjects had an average of 188 days of ICS supply. Restricted compared with unrestricted coverage was associated with reductions in ICS use from 2003–2004 (-15.5 days-of-supply, 95% confidence interval (CI): -25.0 to -6.0). Among patients using higher-cost ICS drugs in 2003 (n = 662), more restricted versus unrestricted coverage subjects switched to the lower-cost ICS in 2004 (39.8% vs. 10.3%). Restricted coverage was not associated with decreased ICS use (2003–2004) among patients who switched to the lower-cost ICS (18.7 days-of-supply, CI: -27.5 to 65.0), but was among patients who did not switch (-38.6 days-of-supply, CI: -57.0 to -20.3). In addition, restricted coverage was associated with decreases in ICS use among patients with both higher- and lower-risk asthma (-15.0 days-of-supply, CI: -41.4 to 11.44; and -15.6 days-of-supply, CI: -25.8 to -5.3, respectively).

Conclusion

In this elderly population, patients reduced their already low ICS use in response to losing drug coverage. Switching to the lower-cost ICS mitigated reductions in use among patients who previously used higher-cost drugs. Additional work is needed to assess barriers to switching ICS drugs and the clinical effects of these drug use changes.
Serpins in T cell immunity
Authors: Bots Michael , Medema Jan Paul
Published: July 2008

Serine protease inhibitors (serpins) are a family of proteins that are important in the regulation of several biological processes. This mainly involves the inhibition of serine proteases, although some serpins inhibit a different class of proteases or even function without inhibitory activity. In contrast to other protease inhibitor families, serpins inhibit their target proteases by a specific mechanism, which depends on a change in conformation. This review primarily focuses on one subgroup of serpins—ovalbumin (ov)-serpins. Different than most members of the family, this group of serpins lacks secretion signal sequences and therefore, mainly functions intracellularly. In addition to expression in most normal tissues, ov-serpins can be found in multiple different cells of the immune system. Interestingly, expression of ov-serpins in these cells is tightly regulated, indicating a role for these serpins in the regulation of immune responses. The role of serpins in the immune response will be the topic of this review.
Iron, zinc, copper, lead and cadmium contents in Ruppia maritima from a Mediterranean coastal lagoon: monthly variation and distribution in different plant fractions
Authors: Malea Paraskevi , Boubonari Theodora , Kevrekidis Theodoros
Published: July 2008

Metal concentrations and quantities were determined monthly in different fractions of the submerged angiosperm Ruppia maritima in Monolimni Lagoon, Aegean Sea. Concentrations were the highest in the roots, suggesting that the sediment-to-root pathway is a principal uptake route of metals. Most metals were equally distributed between rhizomes plus stems and leaves; Fe accumulated greatly in the rhizomes plus stems, whereas Cu occurred mostly in the leaves. Positive correlations were found between metal concentrations in different plant parts, suggesting metal translocation. Most metal concentrations in the different parts declined during the growing season. Iron and Cd accumulation was found to be associated with temperature, which strongly influences the plant growth; additionally, Fe and Cd concentrations in plant tissues were negatively correlated with leaf, rhizome plus stem biomass. Copper concentrations in the roots showed a converse monthly pattern. No metal concentration in plant fractions was positively correlated with concentrations in the water or sediments. Metal quantities (μg m-2) stored in the plant generally increased 2- to 4-fold during the growing season. Evidence that return to sediments is a major fate of these quantities is provided by the seasonal pattern in sediment metal concentrations.
Singing Through the Looking Glass: Child's Play and Learning in Medieval Italy
Authors: Long Michael
Published: July 2008

This study explores the context for a small monophonic Latin song preserved in an eclectic Italian anthology manuscript produced around the turn of the fifteenth century. The song bears the Italian heading L'antefana di Ser Lorenzo, and is presumably connected to the Florentine composer Lorenzo Masini. “Diligenter advertant chantores” (as the Latin text begins) attracted considerable attention when it was first made widely available in facsimiles of the mid-twentieth century. Scholars of late medieval music, confronted by the song's apparent intellectual virtuosity and the diabolical excess of its so-called musica ficta signs, drew the conclusion that its musical context lay hidden within the history of music theory and perhaps even in its most esoteric corners. But repositioned against a new and still-emerging understanding of the pedagogical practices of the ars grammatica and ars memorativa, L'antefana takes on a different sort of historical significance. Details of its previously neglected text and the evidence of its fantastical notation suggest that it is a simple riddle intended for the youngest singers, likely a learning game of a very rudimentary sort (one of several considered in this article). Such classroom amusements still remain childhood constants, bridging the supposed gap between medieval and modern musical lives.
Race, Racial Concentration, and the Dynamics of Educational Inequality Across Urban and Suburban Schools
Authors: Lleras Christy
Published: July 2008

This study uses national data from the National Educational Longitudinal Study to model educational inequality as a feedback process among course placement, student engagement, and academic achievement, separately for students in schools with high and low percentages of African American students. Results find strong effects of placement, engagement, and performance on one another over time and across both school types. However, the results also show that racial segregation is detrimental to the overall learning process for students between 8th and 10th grade. The author concludes that White and African American students in predominantly Black, particularly urban, schools are significantly disadvantaged at each point of the learning process compared to students in other school types.
Ultrastructure of Islet Microcirculation, Pericytes and the Islet Exocrine Interface in the HIP Rat Model of Diabetes
Authors: Hayden Melvin R. , Karuparthi Poorna R. , Habibi Javad , Lastra Guido , Patel Kamlesh , Wasekar Chetan , Manrique Camila Margarita , Ozerdem Ugur , Stas Sameer , Sowers James R.
Published: July 2008

Context: The transgenic human islet amyloid polypeptide (HIP) rat model of type 2 diabetes mellitus (T2DM) parallels the functional and structural changes in human islets with T2DM. Objective: The transmission electron microscope (TEM) was utilized to observe the ultrastructural changes in islet microcirculation. Methods: Pancreatic tissue from male Sprague Dawley rats (2, 4, 8, 14 months) were used as controls (SDC) and compared to the 2-, 4-, 8- and 14-month-old HIP rat models. Results: The 2-month-old HIP model demonstrated no islet or microcirculation remodeling changes when compared to the SDC models. The 4-month-old HIP model demonstrated significant pericapillary amyloid deposition and diminution of pericyte foot processes as compared to the SDC models. The 8-month-old model demonstrated extensive islet amyloid deposition associated with pericyte and β-cell apoptosis when compared with SDC. The 14-month-old HIP model demonstrated a marked reduction of β-cells and intra-islet capillaries with near complete replacement of islets by amyloidoses. Increased cellularity in the region of the islet exocrine interface was noted in the 4- to 14-month-old HIP models as compared to SDC. In contrast to intra-islet capillary rarefaction there was noticeable angiogenesis in the islet exocrine interface. Pericytes seemed to be closely associated with collagenosis, intra-islet adipogenesis and angiogenesis in the islet exocrine interface. Conclusion: The above novel findings regarding the microcirculation and pericytes could assist researchers and clinicians in a better morphological understanding of T2DM and lead to new strategies for prevention and treatment of T2DM.
Role of Oxidative Stress and NFkB in Hypoxia-Induced Pulmonary Edema
Authors: Sarada Sagi , Himadri Patir , Mishra Chitaranjan , Geetali Pradhan , Ram Mastoori Sai , Ilavazhagan Govindan
Published: July 2008

Hypoxia is well known to increase the free radical generation in the body, leading to oxidative stress. In the present study, we have determined whether the increased oxidative stress further upregulates the nuclear transcription factor (NFkB) in the development of pulmonary edema. The rats were exposed to hypobaric hypoxia at 7620 m (280 mm Hg) for different durations, that is, 3 hrs, 6 hrs, 12 hrs, and 24 hrs at 25 ± 1°C. The results revealed that exposure of animals to hypobaric hypoxia led to a significant increase in vascular leakage, with time up to 6 hrs (256.38 ± 61 rfu/g) as compared with control (143.63 ± 60.1 rfu/g). There was a significant increase in reactive oxygen species, lipid peroxidation, and superoxide dismutase levels, with a concurrent decrease in lung glutathione peroxidase activity. There was 13-fold increase in the expression of NFkB level in nuclear fraction of lung homogenates of hypoxic animals over control rats. The DNA binding activity of NFkB was found to be increased significantly ( P < 0.001) in the lungs of rats exposed to hypoxia as compared with control. Further, we observed a significant increase in proinflammatory cytokines such as IL-1, IL-6, and TNF-α with concomitant upregulation of cell adhesion molecules such as ICAM-I, VCAM-I, and P-selectin in the lung of rats exposed to hypoxia as compared with control. Interestingly, pretreatment of animals with curcumin (NFkB blocker) attenuated hypoxia-induced vascular leakage in lungs with concomitant reduction of NFkB levels. The present study therefore reveals the possible involvement of NFkB in the development of pulmonary edema.
Pulmonary Histopathology in an Experimental Model of Chronic Aspiration Is Independent of Acidity
Authors: Downing Tacy E. , Sporn Thomas A. , Bollinger R. Randal , Davis R. Duane , Parker William , Lin Shu S.
Published: July 2008

Gastroesophageal reflux has become a major health concern in industrialized countries, with drugs aimed at blocking acid production being more frequently prescribed than any other drug. Damage to lung tissue as a result of chronic aspiration of gastric fluid is a primary health risk associated with gastro-esophageal reflux, with such aspiration being suspected in the induction or exacerbation of asthma and other lung diseases. In this study, a rodent model of chronic aspiration was used to characterize the pulmonary histopathology produced by repetitive aspiration events and to investigate the pathologic roles of individual gastric fluid components such as acid and particulate food matter. Rats exposed to chronic aspiration of whole gastric fluid developed a pathology distinct from that of acute lung injury, characterized by granulomatous interstitial pneumonitis with prominent formation of multinucleated giant cells. This pattern of injury could be reproduced with chronic aspiration of particulate food matter and with chronic aspiration of pH-neutralized gastric fluid, but not with chronic aspiration of hydrochloric acid. Thus, since acid-neutralizing therapy is currently the mainstay of treatment for patients with reflux-associated respiratory symptoms, these results strongly suggest that alternative therapeutic approaches aimed at preventing chronic-aspiration induced lung injury may be warranted.
Matrix Metalloproteinase-3 Enhances the Free Fatty Acids-Induced VEGF Expression in Adipocytes Through Toll-Like Receptor 2
Authors: Kawamura Toru , Murakami Kentaro , Bujo Hideaki , Unoki Hiroyuki , Jiang Meizi , Nakayama Toshinori , Saito Yasushi
Published: July 2008

Infiltrated macrophages (Mϕ) are believed to cause pathological changes in the surrounding adipocytes through the secretion of active molecules in visceral fat. Matrix metalloproteinase (MMP)-3 is secreted from Mϕ, and enhances expression of the inflammatory cytokines through the activation of toll-like receptor (TLR) 2. Visceral adipocytes express high levels of vascular endothelial growth factor (VEGF), and the degree of visceral fat accumulation is associated with the plasma VEGF concentration in obese subjects. The aim of the study is to clarify the role of MMP-3 in the enhancement of the free fatty acids (FFAs)-induced VEGF expression through TLR2 in visceral adipocytes. One mM FFAs induced VEGF mRNA and protein expression in 3T3-L1 adipocytes. The FFAs-induced VEGF expression was mostly mediated by TLR2. A high fat intake increased the VEGF mRNA expression in visceral fat and the VEGF concentration in plasma, accompanied with the increase in the plasma FFAs concentration in mice. These increases were largely inhibited in TLR2-deficient mice. The FFAs-induced VEGF expression was increased in the presence of Mϕ-conditioned medium (CM) in adipocytes, and the enhancement was inhibited by a MMP-3 inhibitor or a neutralizing antibody against MMP-3. The active form of MMP-3 induced the VEGF mRNA expression, as well as TLR2, in adipocytes. The increase in the VEGF expression by MMP-3 was inhibited by the treatment with siRNA for TLR2. The enhancement of FFAs-induced TLR2 expression by Mϕ-CM was inhibited by blocking of the MMP-3. The increase in the VEGF mRNA expression by Mϕ-CM or MMP-3 was partially inhibited by a neutralizing antibody against TNF-α. These results indicate that MMP-3 in Mϕ-CM enhances the FFAs-induced VEGF expression in adipocytes through the increase in the TLR2 expression. The MMP-3 secreted from the infiltrated Mϕ may be a regulator of the VEGF expression in visceral adipocytes.
Renal Activity of Akt Kinase in Obese Zucker Rats
Authors: Ždychová Jana , Kazdová Ludmila , Pelikanová Terezie , Lindsley Jessie N. , Anderson Sharon , Komers Radko
Published: July 2008

Insulin resistance (IR) and consequent hyperinsulinemia are hallmarks of Type 2 diabetes (DM2). Akt kinase (Akt) is an important molecule in insulin signaling, implicated in regulation of glucose uptake, cell growth, cell survival, protein synthesis, and endothelial nitric oxide (NO) production. Impaired Akt activation in insulin-sensitive tissues contributes to IR. However, Akt activity in other tissues, particularly those affected by complications of DM2, has been less studied. We hypothesized that hyperinsulinemia could have an impact on activity of Akt and its effectors involved in regulation of renal morphology and function in DM2. To address this issue, renal cortical Akt was determined in obese Zucker rats (ZO), a model of DM2, and lean controls (ZL). We also studied expression and phosphorylation of the mammalian target of rapamycin (mTOR) and endothelial NO synthase (eNOS), molecules downstream of Akt in the insulin signaling cascade, and documented modulators of renal injury. Akt activity was measured by a kinase assay with GSK-3 as a substrate. Expression of phosphorylated (active) and total proteins was measured by immunoblotting and immunohistochemistry. Renal Akt activity was increased in ZO as compared to ZL rats, in parallel with progressive hyperinsulinemia. No differences in Akt were observed in the skeletal muscle. Corresponding to increases in Akt activity, ZO rats demonstrated enhanced phosphorylation of renal mTOR. Acute PI3K inhibition with wortmannin (100 μg/kg) attenuated renal Akt and mTOR activities in ZO, but not in ZL rats. In contrast to mTOR, eNOS phosphorylation was similar in ZO and ZL rats, despite higher total eNOS expression. In conclusion, ZO rats demonstrated increases in renal Akt and mTOR activity and expression. However, eNOS phosphorylation did not follow this pattern. These data suggest that DM2 is associated with selective IR in the kidney, allowing pro-growth signaling via mTOR, whereas potentially protective effects mediated by eNOS are blunted.