bluuebunny/crossref_metadata_2025 huggingface dataset:
Perceived social network support and well-being in same-sex versus mixed-sex romantic relationships
Authors: Blair Karen L. , Holmberg Diane
Published: October 2008

A theoretical model was tested, in which better perceived social network support specifically for a romantic relationship was hypothesized to predict higher relationship well-being which, in turn, would predict more positive mental and physical health outcomes for relationship partners. Furthermore, the model was tested on participants in both same-sex (i.e., homosexual, n = 183) and mixed-sex (i.e., heterosexual, n = 275) relationships. Structural equation modelling indicated that the hypothesized model did fit the data very well; furthermore, no differences in model fit were found between the two relationship groups. Support specifically for the relationship remained a highly significant predictor of the outcome variables, even when general social support and support for one's sexual orientation were controlled.
Relational uncertainty, partner interference, and infertility: A qualitative study of discourse within online forums
Authors: Steuber Keli Ryan , Haunani Solomon Denise
Published: October 2008

Infertility afflicts one in six couples and confronts partners with life decisions that have long-term implications for their partnerships. The authors analyzed discourse from online discussion board strings and blogs (N = 438) to consider how this reproductive disability is both affected by and transforms the marital relationship. Specifically, a relational turbulence model lens was used to gain insight into the salient relational issues of couples coping with infertility. A qualitative theme analysis revealed two relational uncertainty themes (relational invalidation and implications of blame), two partner interference themes (supremacy of the pregnancy goal and violated expectations for treatment involvement), and two identity themes (strengthened relational identity and personal identity shifts).
Student Evaluations of Teaching: Are They Related to What Students Learn?
Authors: Clayson Dennis E.
Published: October 2008

Although the student evaluation of teaching has been extensively researched, no general consensus has been reached about the validity of the process. One contentious issue has been the relationship between the evaluations and learning. If good instruction increases the amount of learning that takes place, then learning and the evaluations should be validly related to each other. A review of the literature shows that attempts to find such a nomological relationship has been complicated by practice, methodology, and interpretation. A meta-analysis of the literature shows that a small average relationship exists between learning and the evaluations but that the association is situational and not applicable to all teachers, academic disciplines, or levels of instruction. It is concluded that the more objectively learning is measured, the less likely it is to be related to the evaluations.
A Deep-Blue Electroluminescence from 2,5-Diphenyl-1,3,4-oxadiazole and Polyfluorene Copolymer End-capped with Triphenylamine
Authors: Ishii Junichi , Sunaga Tomoyasu , Deguchi Shingo , Tsukioka Miyuki
Published: October 2008

An electron-transporting 2,5-bis(4-bromophenyl)-1,3,5-oxadiazole (OXD) was incorporated by copolymerization into polyfluorene (PF) end-capped with a 4-bromo-4',4"-dimethyltriphenylamine (TPA) main chains on the Yamamoto coupling method to improve the initial electroluminescence (EL) color stability against applied voltage and the device operation lifetime. The copolymer, PF/OXD-TPA, possessed a high molecular weight enough for film-forming ability and excellent solution-processability, that is, good solubility in common organic solvents such as toluene. An EL device fabricated using this copolymer as a polymeric emission layer allowed the generation of a strong deep-blue EL peaking at 424 nm with a comparatively high EL efficiency of 0.47 cd A -1, and its color was extremely stable against applied voltage within 527 V. The incorporation of OXD units into the PF-TPA system also improved the operation lifetime, although it is not a practical level for displays. The results are probably attributed to the great roles of the incorporated OXD units for disturbing the formation of fluorene excimer sites and for tuning the hole/electron mobility balance..
Synthesis and Characterization of bis (5-Cyanato Naphthalene-1 Oxy) Methyl Phenyl Silane Epoxy Composites
Authors: Thulasiraman V. , Sarojadevi M.
Published: October 2008

A novel siloxane containing dicyanate was synthesized from the condensation reaction of dichloro methyl phenylsilane with 1, 5 dihydroxynaphthalene in a 1 : 2 ratio using triethylamine as catalyst. A new dicyanate was prepared by treating CNBr with synthesized silane containing diol in the presence of triethyl amine as catalyst at —10 to 5 °C. The dicyanate was characterized by Fourier transform infrared spectroscopy (FTIR) and NMR. The curing reaction of the prepared dicyanate and epoxy blends was studied using differential scanning calorimetry. The prepared dicyanate was blended with commercial epoxy resin in different ratios (3, 6 and 9%) and cured at 120 °C for 1 h, 150 °C for 1 h, 220 °C for 1 h using diamino diphenyl methane as the curing agent. The composite laminates with glass fiber were also fabricated using the same composition. Cured neat resin and epoxy blends were characterized by FTIR. The mechanical properties such as tensile strength, flexural strength, and fracture toughness of the composites were measured by adopting ASTM D 3039, D 790, and D 5528, respectively. The tensile strength increased with increasing cyanate content (3, 6, and 9%) from 55 to 62 MPa. Dynamic mechanical analysis shows that with increasing cyanate content in the composite the storage modulus moderately increased in comparison with the neat epoxy composite. There was not much difference in the values of storage modulus at 50 °C and that at 100 °C, showing that the synthesized cyanate has better thermo mechanical characteristics. The flame retardant property of epoxy—cyanate blend was observed to be 50, 36 and 25 s for 3, 6 and 9%, respectively, which showed that the silane-containing cyanate polymer had better flame retardant properties.
Electrical Transport Mechanism in Polyaniline/Formvar Blend Films
Authors: Ebrahim Shaker
Published: October 2008

Polyaniline (PANI) was synthesized chemically and doped with camphor sulfonic acid. New PANI/formvar blend films were prepared using solution blending. These blend films were characterized by UV-visible, Fourier transform infrared spectra and scanning electron microscopy to investigate their optical, structural and morphological properties. It was found that the percolation threshold of these blend films is 4.4 wt.% of PANI. The dc and ac conductivities of these blend films were measured at a temperature range from 70 to 300 K in the frequency range of 10 kHz—1 MHz. The temperature dependence of the dc conductivity of the PANI/formvar blend films followed the three-dimensional variable range hopping. Temperature variation of frequency exponents in this blend suggests that ac conduction is attributed to be correlated to barrier hopping.
The New View in Activism and Academics 10 Years On
Authors: Tiefer Leonore
Published: October 2008

This special issue of Feminism & Psychology presents a sampling of the type of work stimulated by The New View Campaign against the medicalization of sex, c. 2008. In this introduction, I offer a brief history of the New View Campaign (1999—2008) and show how the articles in this special issue illustrate many of its major themes. In closing, I suggest future directions for New View-inspired research and theory.
Queering The New View
Authors: Iasenza Suzanne
Published: October 2008

This article focuses on why lesbians, gay men, bisexuals and transgendered people should care about the New View Campaign and describes how the New View approach can be used in both pedagogical and clinical settings with queer clients. Case material illustrating the clinical application of New View concepts is included.
Qualitative Research on the Attitudes Toward Teenage Sexual Behavior of Chinese British Families
Authors: Juping Yu
Published: October 2008

Qualitative approaches have been increasingly used to explore ethnic differences in teenage sexual behavior, and methodological issues of conducting such research often remain unaddressed. This article discusses issues related to sampling, rapport, language, and ethnical considerations arising while undertaking research on attitudes toward teenage sexual behavior held by Chinese British families. It highlights the value of using snowball sampling, the importance of establishing rapport, and some advantages of matching the ethnic background between researcher and participants. The researcher's gender and social and cultural backgrounds affect research processes and findings, and this itself merits further reflection.
New Media, Networking and Phatic Culture
Authors: Miller Vincent
Published: October 2008

This article will demonstrate how the notion of 'phatic communion' has become an increasingly significant part of digital media culture alongside the rise of online networking practices. Through a consideration of the new media objects of blogs, social networking profiles and microblogs, along with their associated practices, I will argue, that the social contexts of 'individualization' and 'network sociality', alongside the technological developments associated with pervasive communication and 'connected presence' has led to an online media culture increasingly dominated by phatic communications. That is, communications which have purely social (networking) and not informational or dialogic intents. I conclude with a discussion of the potential nihilistic consequences of such a culture.
The Labour of User Co-Creators
Authors: Banks John , Humphreys Sal
Published: October 2008

Co-creative relations among professional media producers and consumers indicate a profound shift in which our frameworks and categories of analysis (such as the traditional labour theory of value) that worked well in the context of an industrial media economy are perhaps less helpful than before. Can this phenomenon just be explained as the exploitative extraction of surplus value from the work of users, or is something else, potentially more profound and challenging, playing out here? Does consumer co-creation contribute to the precarious conditions of professional creative workers? This article draws from ethnographic research undertaken from 2000 to 2005 with Auran games (a game development company based in Brisbane, Australia) to engage with debates about the status of user co-creation as labour. The article argues that as a hybrid and emergent social network market these relationships introduce a form of creative destruction to labour relations in the context of the creative industries.
Engineering affective atmospheres on the moving geographies of the 1897 Andrée expedition
Authors: McCormack Derek P.
Published: October 2008

How might the dynamic materiality of atmosphere be addressed in ways that register simultaneously its meteorological and affective qualities? The present article considers this question via a discussion of the kinds of atmospheric spaces in which the emergence and experience of modern balloon (or aerostatic) flight is implicated. In doing so it argues that aerostatic flight can be understood simultaneously as a technology for moving through atmosphere in a meteorological sense and as an event generative, at least potentially, of atmospheres in an affective sense. This argument is exemplified via a discussion of a particularly notable instance of balloon flight: the attempt, in 1897 by a Swedish engineer, Salomon August Andrée, and two companions, to fly to the North Pole in a hydrogen-filled balloon. Drawing upon a range of contemporaneous accounts, the article makes three claims about the expedition: first, that it can be understood, following Spinoza, as an effort to engineer a mode of addressing the meteorological atmosphere as a relational field of affect; second, that the passage of the expedition can be understood in terms of the registering of atmospheres (in both meteorological and affective terms) in moving, sensing bodies; and third, that the expedition was also generative of a distributed space of anticipation and expectancy. In concluding, the article speculates upon how conceiving of atmospheric space as simultaneously as meteorological and affective might contribute to recent attempts to rethink the materialities of cultural geographies.
Comparison of fatigue behaviour between resistance spot and friction stir spot welded aluminium alloy sheets
Authors: Uematsu Y. , Tokaji K.
Published: October 2008

Tensile shear fatigue tests have been performed using resistance spot welded (RSW) joint and friction stir spot welded (FSSW) joint of aluminium alloy sheets. When fatigue strength was characterised in terms of applied load, RSW joint showed higher fatigue strength than FSSW joint in the entire load range, while the fatigue strength normalised with respect to the nugget area was higher in FSSW joint than in RSW joint. Friction stir spot welded joint exhibited a very small scatter of fatigue life compared with RSW joint, indicating that FSSW is a very stable and reliable joining method. Macroscopic fatigue fracture modes were similar in both joints: nugget shear fracture in high applied load region and parent sheet fracture in low applied load region. It was indicated that geometrical factors around the weld zone played a dominant role in determining the fatigue strength and fracture mechanism of the joints.
Solid state spot joining of sheet materials using consumable bit
Authors: Miles M. P. , Kohkonen K. , Packer S. , Steel R. , Siemssen B. , Sato Y. S.
Published: October 2008

A new spot joining technology relying on a consumable joining bit has been developed and evaluated on dual phase (DP) 980 steel and a dissimilar combination of aluminium alloy 5754-O and DP 980. This new process, called friction bit joining (FBJ), uses a consumable bit to create a solid state joint in sheet materials by the action of cutting and frictional bonding. FBJ lap shear fracture loads were 14˙7 kN for 1˙4 mm DP 980 compared to 16˙6 kN for RSW, for the same spot diameters. FBJ of a dissimilar combination of aluminium alloy 5754-O and DP 980 produced joints with average lap shear fracture load of 6˙3 kN. This strength is greater than lap shear fracture load obtained by self-piercing riveting (SPR) in HSLA 350 bonded to AA 5754-O.
Finite element analysis of effects of soft zones on formability of laser welded advanced high strength steels
Authors: Panda S. K. , Kuntz M. L. , Zhou Y.
Published: October 2008

Applications of advanced high strength steels in tailor welded blanks are a major focus to reduce vehicle weight and manufacturing cost, and to improve part performance. In the present work, formability of two types of laser welded steels in biaxial stretch forming has been studied. Laser welded blanks of the dual phase steel showed larger reduction of formability than those of high strength low alloy steel. This was due to formation of soft zones in the outer heat affected zone of dual phase steel where strain localisation and fracture occurred. Finite element simulations of dome testing incorporating local weld zone properties were able to accurately predict experimentally observed behaviour including deformation patterns and failure locations. In particular, the simulations have shown that under matching of the softened heat affected zone leads to reduced formability by localisation of strain; and that the fracture location changes from radial to circumferential plane when the flow curve of soft zone is evenly matched with the base metal. It was also concluded that the width of the soft zone has minor influence on formability during biaxial stretch forming.
Control of nitrogen content and porosity in gas tungsten arc welding of high nitrogen steel
Authors: Zhao L. , Tian Z. L. , Peng Y.
Published: October 2008

In welding of high nitrogen steel (HNS), it is essential to control the nitrogen content and porosity in the weld metal. In this paper, the influence of shielding gas composition and heat input on the nitrogen content and porosity in the weld metal of HNS was investigated by gas tungsten arc welding. The experimental results indicate that the weld nitrogen content increases as N2 in the shielding gas is increased in the same heat input of welding. The weld nitrogen content decreases with increasing the heat input for pure argon used as a shielding gas, whereas it increases with increasing the heat input for the shielding gas including some nitrogen. The nitrogen pore can be avoided when the nitrogen content in the shielding gas is <4% in the heat input range of 528–2340 J mm–1.
Research on production, performance and fibre dispersion of PVA engineering cementitious composites
Authors: Yu J. H. , Li V. C.
Published: October 2008

Polyvinyl alcohol (PVA) fibre is considered as one of the most suitable polymeric fibres to be used as the reinforcement of engineered cementitious composites (ECCs). Research and application have shown that PVA–ECC can significantly counteract the deficiency of ordinary concrete. In the present paper, micromechanics based design theory and fracture mechanics formulation leading to energy and strength criteria to achieve strain hardening and multiple cracking are described. Engineered cementitious composites showing pseudo strain hardening behaviour with over 6% of strain capacity under tension is produced. Uniaxial tensile tests of PVA–ECC are conducted and the results support the validity of the proposed theory. Also viscosity modifying agent plays an important role in the dispersion of the fibres in the matrix. It is shown that a uniform distribution of fibres throughout the bulk of the composite material is crucial to its excellent workability, tight crack width and reduction in the autogenous and drying shrinkage strains.
Cyclic stress–strain characteristics of two microalloyed steels
Authors: Gupta C. , Nagchaudhury J. , Chakravartty J. K. , Prasad R. C.
Published: October 2008

The cyclic stress–strain behaviour of two microalloyed steels with different microstructures has been characterised at room temperature under strain controlled low cycle fatigue. The cyclic stress–strain curve in the double logarithmic plot shows a linear relation for both steels. A transition of the cyclic stress–strain curve from softening to hardening with increasing strain amplitude has been observed with respect to the corresponding tensile curve. The strain amplitude for the onset of cyclic softening to hardening transition has been found to be dependent on grain size. The strain lifetime behaviour, estimated from modified universal slopes equation, shows similar trends as Nb or V bearing microalloyed steels. The cyclic characteristics of the two microalloyed steels have been compared with corresponding predeformed state carried out under stress controlled conditions. While, cyclic saturation was observed in case where the extent of predeformation was within the Lüders strain, cyclic softening occurred when it exceeded the Lüders strain. It has been attempted to provide a mechanistic understanding of the differences in the cyclic behaviour of the two steels owing to the microstructure and predeformation.
Towards a lightweight generic computational grid framework for biological research
Authors: Halling-Brown Mark D , Moss David S , Shepherd Adrian J
Published: October 2008

Background

An increasing number of scientific research projects require access to large-scale computational resources. This is particularly true in the biological field, whether to facilitate the analysis of large high-throughput data sets, or to perform large numbers of complex simulations – a characteristic of the emerging field of systems biology.

Results

In this paper we present a lightweight generic framework for combining disparate computational resources at multiple sites (ranging from local computers and clusters to established national Grid services). A detailed guide describing how to set up the framework is available from the following URL: http://igrid-ext.cryst.bbk.ac.uk/portal_guide/.

Conclusion

This approach is particularly (but not exclusively) appropriate for large-scale biology projects with multiple collaborators working at different national or international sites. The framework is relatively easy to set up, hides the complexity of Grid middleware from the user, and provides access to resources through a single, uniform interface. It has been developed as part of the European ImmunoGrid project.
Probabilistic base calling of Solexa sequencing data
Authors: Rougemont Jacques , Amzallag Arnaud , Iseli Christian , Farinelli Laurent , Xenarios Ioannis , Naef Felix
Published: October 2008

Background

Solexa/Illumina short-read ultra-high throughput DNA sequencing technology produces millions of short tags (up to 36 bases) by parallel sequencing-by-synthesis of DNA colonies. The processing and statistical analysis of such high-throughput data poses new challenges; currently a fair proportion of the tags are routinely discarded due to an inability to match them to a reference sequence, thereby reducing the effective throughput of the technology.

Results

We propose a novel base calling algorithm using model-based clustering and probability theory to identify ambiguous bases and code them with IUPAC symbols. We also select optimal sub-tags using a score based on information content to remove uncertain bases towards the ends of the reads.

Conclusion

We show that the method improves genome coverage and number of usable tags as compared with Solexa's data processing pipeline by an average of 15%. An R package is provided which allows fast and accurate base calling of Solexa's fluorescence intensity files and the production of informative diagnostic plots.
A role for SNX5 in the regulation of macropinocytosis
Authors: Lim Jet Phey , Wang Jack TH , Kerr Markus C , Teasdale Rohan D , Gleeson Paul A
Published: October 2008

Background

The mechanisms and components that regulate macropinocytosis are poorly understood. Here we have investigated the role of sorting nexin 5 (SNX5) in the regulation of macropinocytic activity.

Results

SNX5 is abundantly expressed in macrophages, cells very active in macropinocytosis, and is recruited onto newly-formed macropinosomes. LPS treatment of bone marrow-derived macrophages resulted in a 2.5 fold decrease in macropinosome formation that correlates with a reduction in the levels of SNX5. To investigate the relationship between SNX5 levels and macropinocytic activity we examined the formation of macropinosomes in HEK-FlpIn cells stably expressing GFP-SNX5. Constitutive macropinocytosis was increased ~2 fold in HEK-GFP-SNX5 cells compared with parental HEK-FlpIn cells. Furthermore, EGF stimulation resulted in a significant increase in macropinocytosis and there was also a 2.0 fold increase in the generation of macropinosomes in HEK-GFP-SNX5 cells compared with parental HEK-FlpIn cells. SNX5, which interacts specifically with PtdIns(3)Pand PtdIns(3,4)P2through its PX domain, was recruited to regions on the plasma membrane containing EGF receptor or positive for PtdIns(3,4)P2as detected with the PH domain of TAPP1. Treatment with AG1478, an EGF receptor specific tyrosine kinase inhibitor, prevented the recruitment of SNX5 to the cytosolic face of the plasma membrane and inhibited the formation of macropinosomes in response to EGF treatment.

Conclusion

Based on these data, we propose that SNX5 requires the generation of phosphoinositides for recruitment to the plasma membrane and, moreover, influences the level of macropinocytic activity.
Global analysis of gene expression changes during retinoic acid-induced growth arrest and differentiation of melanoma: comparison to differentially expressed genes in melanocytes vs melanoma
Authors: Estler Mary , Boskovic Goran , Denvir James , Miles Sarah , Primerano Donald A , Niles Richard M
Published: October 2008

Background

The incidence of malignant melanoma has significantly increased over the last decade. Some of these malignancies are susceptible to the growth inhibitory and pro-differentiating effects of all-trans-retinoic acid (RA). The molecular changes responsible for the biological activity of RA in melanoma are not well understood.

Results

In an analysis of sequential global gene expression changes during a 4–48 h RA treatment of B16 mouse melanoma cells, we found that RA increased the expression of 757 genes and decreased the expression of 737 genes. We also compared the gene expression profile (no RA treatment) between non-malignant melan-a mouse melanocytes and B16 melanoma cells. Using the same statistical test, we found 1495 genes whose expression was significantly higher in melan-a than in B16 cells and 2054 genes whose expression was significantly lower in melan-a than in B16 cells. By intersecting these two gene sets, we discovered a common set of 233 genes whose RNA levels were significantly different between B16 and melan-a cells and whose expression was altered by RA treatment. Within this set, RA treatment altered the expression of 203 (87%) genes toward the melan-a expression level. In addition, hierarchical clustering showed that after 48 h of RA treatment expression of the 203 genes was more closely related to the melan-a gene set than any other RA treatment time point. Functional analysis of the 203 gene set indicated that RA decreased expression of mRNAs that encode proteins involved in cell division/cell cycle, DNA replication, recombination and repair, and transcription regulation. Conversely, it stimulated genes involved in cell-cell signaling, cell adhesion and cell differentiation/embryonic development. Pathway analysis of the 203 gene set revealed four major hubs of connectivity: CDC2, CHEK1, CDC45L and MCM6.

Conclusion

Our analysis of common genes in the 48 h RA-treatment of B16 melanoma cells and untreated B16 vs. melan-a data set show that RA "normalized" the expression of genes involved in energy metabolism, DNA replication, DNA repair and differentiation. These results are compatible with the known growth inhibitory and pro-differentiating effects of RA. Pathway analysis suggests that CDC2, CHEK1, CDC45L and MCM6 are key players in mediating the biological activity of RA in B16 melanoma cells.
Transcriptional regulation of subclass 5b fimbriae
Authors: Bodero Maria D , Harden Elizabeth A , Munson George P
Published: October 2008

Background

Enterotoxigenic Escherichia coli (ETEC) is a major cause of infant and child mortality in developing countries. This enteric pathogen causes profuse watery diarrhea by elaborating one or more enterotoxins that intoxicate eukaryotic cells and ultimately leads to a loss of water to the intestinal lumen. Virulence is also dependent upon fimbrial adhesins that facilitate colonization of the small intestine.

Results

The expression of CS1 fimbriae is positively regulated by Rns, a member of the AraC/XylS superfamily of transcriptional regulators. Based on fimbrial protein homology, CS1 fimbriae have been categorized as subclass 5b along with CS17, CS19, and PCFO71 fimbriae. In this study we show that Rns positively regulates the expression of these other subclass 5b members. DNase I footprinting revealed a Rns binding site adjacent to the -35 hexamer of each fimbrial promoter. The CS17 and PCFO71 fimbrial promoters carry a second Rns binding site centered at -109.5, relative to the Rns-dependent transcription start site. This second binding site is centered at -108.5 for the CS19 promoter. Mutagenesis of either site reduced Rns-dependent transcription from each promoter indicating that the molecules bound to these sites apparently function independently of one another, with each having an additive effect upon fimbrial promoter activation.

Conclusion

This study demonstrates that the ETEC virulence regulator Rns is required for the expression of all known 5b fimbriae. Since Rns is also known to control the expression of additional ETEC fimbriae, including those within subclasses 5a and 5c, the inactivation or inhibition of Rns could be an effective strategy to prevent ETEC infections.
Amphetamine and pseudoephedrine cross-tolerance measured by c-Fos protein expression in brains of chronically treated rats
Authors: Ruksee Nootchanart , Tongjaroenbuangam Walaiporn , Casalotti Stefano O , Govitrapong Piyarat
Published: October 2008

Background

Pseudoephedrine is a drug commonly prescribed as a nasal decongestant and bronchodilator and is also freely available in cold remedies and medications. The structural and pharmacological similarity of pseudoephedrine to amphetamine has led to evaluation of its psychomotor stimulant properties within the central nervous system. Previous investigations have shown that the acute responses to pseudoephedrine were similar to those of amphetamine and other psychostimulants.

Results

This study examined the effect of chronic administration of pseudoephedrine in rat nucleus accumbens and striatum and identified three further similarities to amphetamine. (i) Chronic exposure to pseudoephedrine reduced the c-Fos response to acute pseudoephedrine treatment suggesting that pseudoephedrine induced tolerance in the animals. (ii) In animals chronically treated with amphetamine or pseudoephedrine the acute c-Fos response to pseudoephedrine and amphetamine was reduced respectively as compared to naïve animals indicating cross-tolerance for the two drugs. (iii)The known involvement of the dopamine system in the response to amphetamine and pseudoephedrine was further confirmed in this study by demonstrating that pseudoephedrine similarly to amphetamine, but with lower potency, inhibited [3H]dopamine uptake in synaptosomal preparations.

Conclusion

This work has demonstrated further similarities of the effect of pseudoephedrine to those of amphetamine in brain areas known to be associated with drug addiction. The most significant result presented here is the cross tolerance effect of amphetamine and psudoephedrine. This suggests that both drugs induce similar mechanisms of action in the brain. Further studies are required to establish whether despite its considerable lower potency, pseudoephedrine could pose health and addiction risks in humans similar to that of known psychostimulants.
Refractive change following pseudophakic vitrectomy
Authors: Byrne Sinead , Ng James , Hildreth Anthony , Danjoux Jean-Pierre , Steel David HW
Published: October 2008

Background

To assess the occurrence and magnitude of refractive change in pseudophakic eyes undergoing 20 gauge pars plana vitrectomy without scleral buckling and to investigate possible aetiological factors.

Methods

Retrospective case note review of 87 pseudophakic eyes undergoing 20 gauge pars plana vitrectomy for a variety of vitreo-retinal conditions over a three-year period. Anterior chamber depth (ACD) was measured before and after vitrectomy surgery in 32 eyes. Forty-three pseudophakic fellow eyes were used as controls.

Results

Eighty-seven eyes (84 patients) were included in the study. Mean spherical equivalent refraction prior to vitrectomy was -0.20 dioptres, which changed to a mean of -0.65 dioptres postoperatively (standard deviation of refractive change 0.59, range-2.13 to 0.75 dioptres) (p < 0.001). Sixty-one of the 87(70%) eyes experienced a myopic shift and 45(52%) eyes had a myopic shift of -0.5 dioptres or more. Mean fellow eye refraction was -0.19 dioptres preoperatively and -0.17 dioptres postoperatively (p = 0.14)(n = 37)

Mean ACD preoperatively was 3.29 mm and postoperatively 3.27 mm (p = 0.53) (n = 32) and there was no significant change in ACD with tamponade use. Regression analysis revealed no statistically significant association between changes in anterior chamber depth, as well as a wide variety of other pre-, intra and postoperative factors examined, and the refractive change observed.

Conclusion

Significant refractive changes occur in some pseudophakic patients undergoing 20 g pars plana vitrectomy. The mean change observed was a small myopic shift but the range was large. The aetiology of the refractive change is uncertain.
Development of a strategy to functionalize a dextrin-based hydrogel for animal cell cultures using a starch-binding module fused to RGD sequence
Authors: Moreira Susana M , Andrade Fábia K , Domingues Lucíla , Gama Miguel
Published: October 2008

Background

Several approaches can be used to functionalize biomaterials, such as hydrogels, for biomedical applications. One of the molecules often used to improve cells adhesion is the peptide Arg-Gly-Asp (RGD). The RGD sequence, present in several proteins from the extra-cellular matrix (ECM), is a ligand for integrin-mediated cell adhesion; this sequence was recognized as a major functional group responsible for cellular adhesion. In this work a bi-functional recombinant protein, containing a starch binding module (SBM) and RGD sequence was used to functionalize a dextrin-based hydrogel. The SBM, which belongs to an α-amylase from Bacillus sp. TS-23, has starch (and dextrin, depolymerized starch) affinity, acting as a binding molecule to adsorb the RGD sequence to the hydrogel surface.

Results

The recombinant proteins SBM and RGD-SBM were cloned, expressed, purified and tested in in vitro assays. The evaluation of cell attachment, spreading and proliferation on the dextrin-based hydrogel surface activated with recombinant proteins were performed using mouse embryo fibroblasts 3T3. A polystyrene cell culture plate was used as control. The results showed that the RGD-SBM recombinant protein improved, by more than 30%, the adhesion of fibroblasts to dextrin-based hydrogel. In fact, cell spreading on the hydrogel surface was observed only in the presence of the RGD-SBM.

Conclusion

The fusion protein RGD-SBM provides an efficient way to functionalize the dextrin-based hydrogel. Many proteins in nature that hold a RGD sequence are not cell adhesive, probably due to the conformation/accessibility of the peptide. We therefore emphasise the successful expression of a bi-functional protein with potential for different applications.
Syzygium jambolanum treatment improves survival in lethal sepsis induced in mice
Authors: Maciel Márcia CG , Farias Jardel C , Maluf Michele J , Gomes Eliane A , Pereira Paulo VS , Aragão-Filho Walmir C , Frazão Josias B , Costa Graciomar C , Sousa Sanara M , Silva Lucilene A , Amaral Flávia MM , Russo Momtchilo , Guerra Rosane NM , Nascimento Flávia RF
Published: October 2008

Background

The leaves and the fruits from Syzygium jambolanum DC.(Myrtaceae), a plant known in Brazil as sweet olive or 'jambolão', have been used by native people to treat infectious diseases, diabetes, and stomachache. Since the bactericidal activity of S. jambolanum has been confirmed in vitro, the aim of this work was to evaluate the effect of the prophylactic treatment with S. jambolanum on the in vivo polymicrobial infection induced by cecal ligation and puncture (CLP) in mice.

Methods

C57Bl/6 mice were treated by the subcutaneous route with a hydroalcoholic extract from fresh leaves of S. jambolanum (HCE). After 6 h, a bacterial infection was induced in the peritoneum using the lethal CLP model. The mice were killed 12 h after the CLP induction to evaluate the cellular influx and local and systemic inflammatory mediators' production. Some animals were maintained alive to evaluate the survival rate.

Results

The prophylactic HCE treatment increased the mice survival, the neutrophil migration to infectious site, the spreading ability and the hydrogen peroxide release, but decreased the serum TNF and nitrite. Despite the increased migration and activation of peritoneal cells the HCE treatment did not decrease the number of CFU. The HCE treatment induced a significant decrease on the bone marrow cells number but did not alter the cell number of the spleen and lymph node.

Conclusion

We conclude that the treatment with S. jambolanum has a potent prophylactic anti-septic effect that is not associated to a direct microbicidal effect but it is associated to a recruitment of activated neutrophils to the infectious site and to a diminished systemic inflammatory response.
Sample processing for DNA chip array-based analysis of enterohemorrhagic Escherichia coli (EHEC)
Authors: Basselet Pascal , Wegrzyn Grzegorz , Enfors Sven-Olof , Gabig-Ciminska Magdalena
Published: October 2008

Background

Exploitation of DNA-based analyses of microbial pathogens, and especially simultaneous typing of several virulence-related genes in bacteria is becoming an important objective of public health these days.

Results

A procedure for sample processing for a confirmative analysis of enterohemorrhagic Escherichia coli (EHEC) on a single colony with DNA chip array was developed and is reported here. The protocol includes application of fragmented genomic DNA from ultrasonicated colonies. The sample processing comprises first 2.5 min of ultrasonic treatment, DNA extraction (2×), and afterwards additional 5 min ultrasonication. Thus, the total sample preparation time for a confirmative analysis of EHEC is nearly 10 min. Additionally, bioinformatic revisions were performed in order to design PCR primers and array probes specific to most conservative regions of the EHEC-associated genes. Six strains with distinct pathogenic properties were selected for this study. At last, the EHEC chip array for a parallel and simultaneous detection of genes etpC-stx1-stx2-eae was designed and examined. This should permit to sense all currently accessible variants of the selected sequences in EHEC types and subtypes.

Conclusion

In order to implement the DNA chip array-based analysis for direct EHEC detection the sample processing was established in course of this work. However, this sample preparation mode may also be applied to other types of EHEC DNA-based sensing systems.
Similarity of aberrant DNA methylation in Barrett's esophagus and esophageal adenocarcinoma
Authors: Smith Eric , De Young Neville J , Pavey Sandra J , Hayward Nicholas K , Nancarrow Derek J , Whiteman David C , Smithers B Mark , Ruszkiewicz Andrew R , Clouston Andrew D , Gotley David C , Devitt Peter G , Jamieson Glyn G , Drew Paul A
Published: October 2008

Background

Barrett's esophagus (BE) is the metaplastic replacement of squamous with columnar epithelium in the esophagus, as a result of reflux. It is the major risk factor for the development of esophageal adenocarcinoma (EAC). Methylation of CpG dinucleotides of normally unmethylated genes is associated with silencing of their expression, and is common in EAC. This study was designed to determine at what stage, in the progression from BE to EAC, methylation of key genes occurs.

Results

We examined nine genes (APC, CDKN2A, ID4, MGMT, RBP1, RUNX3, SFRP1, TIMP3, and TMEFF2), frequently methylated in multiple cancer types, in a panel of squamous (19 biopsies from patients without BE or EAC, 16 from patients with BE, 21 from patients with EAC), BE (40 metaplastic, seven high grade dysplastic) and 37 EAC tissues. The methylation frequency, the percentage of samples that had any extent of methylation, for each of the nine genes in the EAC (95%, 59%, 76%, 57%, 70%, 73%, 95%, 74% and 83% respectively) was significantly higher than in any of the squamous groups. The methylation frequency for each of the nine genes in the metaplastic BE (95%, 28%, 78%, 48%, 58%, 48%, 93%, 88% and 75% respectively) was significantly higher than in the squamous samples except for CDKN2A and RBP1. The methylation frequency did not differ between BE and EAC samples, except for CDKN2A and RUNX3 which were significantly higher in EAC. The methylation extent was an estimate of both the number of methylated alleles and the density of methylation on these alleles. This was significantly greater in EAC than in metaplastic BE for all genes except APC, MGMT and TIMP3. There was no significant difference in methylation extent for any gene between high grade dysplastic BE and EAC.

Conclusion

We found significant methylation in metaplastic BE, which for seven of the nine genes studied did not differ in frequency from that found in EAC. This is also the first report of gene silencing by methylation of ID4 in BE or EAC. This study suggests that metaplastic BE is a highly abnormal tissue, more similar to cancer tissue than to normal epithelium.
Cryopreservation/transplantation of ovarian tissue and in vitro maturation of follicles and oocytes: Challenges for fertility preservation
Authors: Varghese Alex C , du Plessis Stefan S , Falcone Tommaso , Agarwal Ashok
Published: October 2008

Cryopreservation of ovarian tissue and in vitro follicle maturation are two emerging techniques for fertility preservation, especially in cancer patients. These treatment regimes are opening up more options and allow for more suitable choices to preserve fertility according to the patient's specific circumstances. If these technologies are to become widely accepted, they need to be safe, easy to perform and must obtain favorable results. The generation of healthy eggs with the normal genetic complement and the ability to develop into viable and healthy embryos requires tight regulation of oocyte development and maturation. Novel freezing techniques such as vitrification, along with whole ovary cryopreservation and three-dimensional follicle cultures, have shown favorable outcomes. The scope of this article is to take a comprehensively look at the challenges still faced in order for these novel technologies to be routinely employed with the aim of successful fertility preservation.
Connective tissue growth factor promoter activity in normal and wounded skin
Authors: Kapoor Mohit , Liu Shangxi , Huh Kun , Parapuram Sunil , Kennedy Laura , Leask Andrew
Published: October 2008

In skin, connective tissue growth factor (CTGF/CCN2) is induced during tissue repair. However, what the exact cell types are that express CTGF in normal and wounded skin remain controversial. In this report, we use transgenic knock-in mice in which the Pacific jellyfish Aequorea victoria enhanced green fluorescent protein (E-GFP) gene has been inserted between the endogenous CTGF promoter and gene. Unwounded (day 0) and wounded (days 3 and 7) skin was examined for GFP to detect cells in which the CTGF promoter was active, α-smooth muscle actin (α-SMA) to detect myofibroblasts, and NG2 expression to detect pericytes. In unwounded mice, CTGF expression was absent in epidermis and was present in a few cells in the dermis. Upon wounding, CTGF expression was induced in the dermis. Double immunolabeling revealed that CTGF-expressing cells also expressed α-SMA, indicating the CTGF was expressed in myofibroblasts. A subset (~30%) of myofibroblasts were also NG2 positive, indicating that pericytes significantly contributed to the number of myofibroblasts in the wound. Pericytes also expressed CTGF. Collectively, these results indicate that CTGF expression in skin correlates with myofibroblast induction, and that CTGF-expressing pericytes are significant contributors to myofibroblast activity during cutaneous tissue repair.
Redox mechanisms in hepatic chronic wound healing and fibrogenesis
Authors: Novo Erica , Parola Maurizio
Published: October 2008

Reactive oxygen species (ROS) generated within cells or, more generally, in a tissue environment, may easily turn into a source of cell and tissue injury. Aerobic organisms have developed evolutionarily conserved mechanisms and strategies to carefully control the generation of ROS and other oxidative stress-related radical or non-radical reactive intermediates (that is, to maintain redox homeostasis), as well as to 'make use' of these molecules under physiological conditions as tools to modulate signal transduction, gene expression and cellular functional responses (that is, redox signalling). However, a derangement in redox homeostasis, resulting in sustained levels of oxidative stress and related mediators, can play a significant role in the pathogenesis of major human diseases characterized by chronic inflammation, chronic activation of wound healing and tissue fibrogenesis. This review has been designed to first offer a critical introduction to current knowledge in the field of redox research in order to introduce readers to the complexity of redox signalling and redox homeostasis. This will include ready-to-use key information and concepts on ROS, free radicals and oxidative stress-related reactive intermediates and reactions, sources of ROS in mammalian cells and tissues, antioxidant defences, redox sensors and, more generally, the major principles of redox signalling and redox-dependent transcriptional regulation of mammalian cells. This information will serve as a basis of knowledge to introduce the role of ROS and other oxidative stress-related intermediates in contributing to essential events, such as the induction of cell death, the perpetuation of chronic inflammatory responses, fibrogenesis and much more, with a major focus on hepatic chronic wound healing and liver fibrogenesis.
Identification of CDK2 substrates in human cell lysates
Authors: Chi Yong , Welcker Markus , Hizli Asli A , Posakony Jeffrey J , Aebersold Ruedi , Clurman Bruce E
Published: October 2008

Background

Protein phosphorylation regulates a multitude of biological processes. However, the large number of protein kinases and their substrates generates an enormously complex phosphoproteome. The cyclin-dependent kinases - the CDKs - comprise a class of enzymes that regulate cell cycle progression and play important roles in tumorigenesis. However, despite intense study, only a limited number of mammalian CDK substrates are known. A comprehensive understanding of CDK function requires the identification of their substrate network.

Results

We describe a simple and efficient approach to identify potential cyclin A-CDK2 targets in complex cell lysates. Using a kinase engineering strategy combined with chemical enrichment and mass spectrometry, we identified 180 potential cyclin A-CDK2 substrates and more than 200 phosphorylation sites. About 10% of these candidates function within pathways related to cell division, and the vast majority are involved in other fundamental cellular processes. We have validated several candidates as direct cyclin A-CDK2 substrates that are phosphorylated on the same sites that we identified by mass spectrometry, and we also found that one novel substrate, the ribosomal protein RL12, exhibits site-specific CDK2-dependent phosphorylation in vivo.

Conclusions

We used methods entailing engineered kinases and thiophosphate enrichment to identify a large number of candidate CDK2 substrates in cell lysates. These results are consistent with other recent proteomic studies, and suggest that CDKs regulate cell division via large networks of cellular substrates. These methods are general and can be easily adapted to identify direct substrates of many other protein kinases.