994 resultados para 179
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Background Ephrin-B2 is the sole physiologically-relevant ligand of the receptor tyrosine kinase EphB4, which is over-expressed in many epithelial cancers, including 66% of prostate cancers, and contributes to cancer cell survival, invasion and migration. Crucially, however, the cancer-promoting EphB4 signalling pathways are independent of interaction with its ligand ephrin-B2, as activation of ligand-dependent signalling causes tumour suppression. Ephrin-B2, however, is often found on the surface of endothelial cells of the tumour vasculature, where it can regulate angiogenesis to support tumour growth. Proteolytic cleavage of endothelial cell ephrin-B2 has previously been suggested as one mechanism whereby the interaction between tumour cell-expressed EphB4 and endothelial cell ephrin-B2 is regulated to support both cancer promotion and angiogenesis. Methods An in silico approach was used to search accessible surfaces of 3D protein models for cleavage sites for the key prostate cancer serine protease, KLK4, and this identified murine ephrin-B2 as a potential KLK4 substrate. Mouse ephrin-B2 was then confirmed as a KLK4 substrate by in vitro incubation of recombinant mouse ephrin-B2 with active recombinant human KLK4. Cleavage products were visualised by SDS-PAGE, silver staining and Western blot and confirmed by N-terminal sequencing. Results At low molar ratios, KLK4 cleaved murine ephrin-B2 but other prostate-specific KLK family members (KLK2 and KLK3/PSA) were less efficient, suggesting cleavage was KLK4-selective. The primary KLK4 cleavage site in murine ephrin-B2 was verified and shown to correspond to one of the in silico predicted sites between extracellular domain residues arginine 178 and asparagine 179. Surprisingly, the highly homologous human ephrin-B2 was poorly cleaved by KLK4 at these low molar ratios, likely due to the 3 amino acid differences at this primary cleavage site. Conclusion These data suggest that in in vivo mouse xenograft models, endogenous mouse ephrin-B2, but not human tumour ephrin-B2, may be a downstream target of cancer cell secreted human KLK4. This is a critical consideration when interpreting data from murine explants of human EphB4+/KLK4+ cancer cells, such as prostate cancer cells, where differential effects may be seen in mouse models as opposed to human clinical situations.
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This article evaluates the adoption and implementation of an Indigenous certification trademark system in Australia. Section II considers the use of copyright law, moral rights provisions and consumer protection laws to protect Indigenous cultural property in Australia. It suggests that there needs to be additional protection under trademark law - especially to deal with problems concerning communal ownership, material form and duration of protection. Section III evaluates the efficacy of the scheme for marks of authenticity established by the National Indigenous Arts Advocacy Association in November 1999. It contends that there were practical problems with the implementation of the scheme and symbolic concerns about the definition of authenticity applied under the regime. Section IV engages in a comparative analysis of other jurisdictions - such as New Zealand, Canada and the United States. It demonstrates that an Indigenous certification mark can be successful, given sufficient support and assistance. The article concludes that there needs to be a sui generis system to protect traditional knowledge at an international level.
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Toughness is the ability of a material to deform plastically and to absorb energy before fracture. The first of its kind, this book covers the most recent developments in the toughening of hard coatings and the methodologies for measuring the toughness of thin films and coatings. The book looks at the present status of toughness for coatings and discusses high-temperature nanocomposite coatings, porous thin films, laser treated surface layers, cracking resistance, indentation techniques, sliding contact fracture, IPN hybrid composites for protection, and adhesion strength.
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A study was undertaken to examine further the effects of perceived work control on employee adjustment. On the basis of the stress antidote model, it was proposed that high levels of prediction, understanding, and control of work-related events would have direct, indirect, and interactive effects on levels of employee adjustment. These hypotheses were tested in a short-term longitudinal study of 137 employees of a large retail organization. The stress antidote measures appeared to be indirectly related to employee adjustment, via their effects on perceptions of work stress. There was weak evidence for the proposal that prediction, understanding, and control would buffer the negative effects of work stress. Additional analyses indicated that the observed effects of prediction, understanding, and control were independent of employees' generalized control beliefs. However, there was no support for the proposal that the effects of the stress antidote measures would be dependent on employees' generalized control beliefs.
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Sustainable construction is gaining worldwide attention and has inspired research to identify and solve the problems involved in its implementation over a project lifecycle. While an impressive number of papers have been published on the topic to date, little has been done to review these papers to identify current research status or provide guidance for future research. This paper reviews existing sustainability papers in 12 internationally renowned construction journals. Based on a three-stage literature review, sustainability papers published in these journals from 2000 to 2012 are analyzed in terms of the annual number of papers published and the research interests involved. The number of sustainability-related papers in construction increases from 30 papers in 2000 to 127 papers in 2012, which shows an increasing trend in sustainability topics. A content analysis identifies seven major research interest in sustainability, including: (1) sustainable project management; (2) sustainability assessment/evaluation; (3) sustainable technology/innovation implementation; (4) sustainable building/infrastructure performance; (5) government policy on sustainability; (6) enterprise sustainability, and; (7) sustainability education. The results of this study provide a reference for scholars and academics to understand the current status of sustainability research in major construction journals.
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Introduction: This study aimed to determine the potential role and guidelines for implementation of skill-based peer mentoring for radiotherapy planning education. Methods: After four weekly mentoring sessions, both Year 3 mentors (n=9) and Year 2 mentees (n=9) were invited to complete a short online questionnaire relating to the impact of the initiative. The tool contained a mixture of Likert-style questions concerning student enjoyment and perceived usefulness of the initiative as well as more qualitative open questions that gathered perceptions of the peer mentoring process, implementation methods and potential future scope. Results: Several key discussion themes related to benefits to each stakeholder group, challenges arising, improvements and potential future directions. There were high levels of enjoyment and perceived value of the mentoring from both sides with 100% of the 18 respondents enjoying the experience. The informal format encouraged further learning, while mentors reported acquisition of valuable skills and gains in knowledge. Conclusions: Peer mentoring has a valuable and enjoyable role to play in radiotherapy planning training and helps consolidate theoretical understanding for experienced students. An informal approach allows for students to adopt the most appropriate mentoring model for their needs while providing them with a free space to engender additional discussion.
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This study investigates friendships between gay sales associates and heterosexual female customers in luxury retail settings. By employing grounded theory methodology, the study integrates theories and findings from diverse literature streams into an original conceptual framework to illustrate the resources gay sales associates and straight female customers receive from and provide to each other during retail exchanges. The study explains why gay male–straight female friendships are uniquely suited for luxury consumption settings. Female customers characterize their friendships with gay sales associates as providing honesty, security, trust, and comfort, which stems from the absence of sexual interest and a lack of inter-female competition. Gay sales associates receive acceptance for who they are and for their displays of unconventional masculinity in retail settings. They also obtain a temporary rite from their female customers, a so-called mandate of privacy, which permits both parties to ignore the bounds of modesty and accept a degree of intimacy. Such intimacy facilitates transactions that require both personalization and customer–employee closeness, such as the selling of high-end apparel, accessories, and jewelry.
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Bone mass acquired during childhood is the primary determinant of adult bone mineral density (BMD) and osteoporosis risk. Bone accrual is subject to genetic influences. Activating and inactivating LRP5 gene mutations elicit extreme bone phenotypes, while more common LRP5 polymorphisms are associated with normal variation of BMD. Our aim was to test the hypothesis that LRP5 gene polymorphisms influence bone mass acquisition during childhood. The association between LRP5 gene polymorphisms and bone size and mineralization was examined in 819 unrelated British Caucasian children (n = 429 boys) aged 9 years. Height, weight, pubertal status (where available), total-body and spinal bone area, bone mineral content (BMC), BMD, and area-adjusted BMC (aBMC) were assessed. Dual-energy X-ray absorptiometry (DXA)-gene associations were assessed by linear regression, with adjustment for age, gender, pubertal status, and body size parameters. There were 140, 79, 12, and 2 girls who achieved Tanner stages I-IV, respectively, and 179 and 32 boys who achieved Tanner stages I and II, respectively. The rs2306862 (N740N) coding polymorphism in exon 10 of the LRP5 gene was associated with spinal BMD and aBMC (each P = 0.01) and total-body BMD and aBMC (P = 0.04 and 0.03, respectively). Adjusting for pubertal stage strengthened associations between this polymorphism and spinal BMD and aBMC (P = 0.01 and 0.002, respectively). Individuals homozygous for the T allele had greater spinal BMD and aBMC scores than those homozygous for the C allele. A dose effect was apparent as the mean spinal BMD and aBMC of heterozygous TC individuals were intermediate between those of their TT and CC counterparts. The N740N polymorphism in exon 10 of LRP5 was associated with spinal BMD and aBMC in pre- and early pubertal children. These results indicate that LRP5 influences volumetric bone density in childhood, possibly through effects on trabecular bone formation.
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The conifer genus Palissya is reviewed giving special attention to assessing the reliability of Gondwanan material referred to this genus. The collection localities of Australasian specimens are mapped on palaeogeographic reconstructions of Eastern Gondwana at relevant times between 179 Ma and 119 Ma. Australasian and other Gondwanan material previously referred to Palissya is considered to differ substantially from the generic diagnosis. Specimens from the Toarcian of Australasia are shown to be allied to Knezourocarpon; this genus is only known from the Toarcian of eastern Australia. Middle Jurassic–Lower Cretaceous Australasian specimens previously referred to Palissya are likely allied to the Knezourocarponaceae fam. nov. The higher taxonomic affinity of this family is unknown but broadly, its structure is suggestive of ginkgoalean or pteridospermous affiliation. Southern hemisphere specimens were probably catkin-like and megascopically very different from the northern hemisphere Palissya and the two groups are unlikely to be closely related. Consequently, genuine Palissya cones and foliage appear to be restricted to the Rhaetian–Lower Jurassic of the northern hemisphere.
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Solid–interstitial fluid interaction, which depends on tissue permeability, is significant to the strain-rate-dependent mechanical behavior of humeral head (shoulder) cartilage. Due to anatomical and biomechanical similarities to that of the human shoulder, kangaroos present a suitable animal model. Therefore, indentation experiments were conducted on kangaroo shoulder cartilage tissues from low (10−4/s) to moderately high (10−2/s) strain-rates. A porohyperelastic model was developed based on the experimental characterization; and a permeability function that takes into account the effect of strain-rate on permeability (strain-rate-dependent permeability) was introduced into the model to investigate the effect of rate-dependent fluid flow on tissue response. The prediction of the model with the strain-rate-dependent permeability was compared with those of the models using constant permeability and strain-dependent permeability. Compared to the model with constant permeability, the models with strain-dependent and strain-rate-dependent permeability were able to better capture the experimental variation at all strain-rates (p<0.05). Significant differences were not identified between models with strain-dependent and strain-rate-dependent permeability at strain-rate of 5×10−3/s (p=0.179). However, at strain-rate of 10−2/s, the model with strain-rate-dependent permeability was significantly better at capturing the experimental results (p<0.005). The findings thus revealed the significance of rate-dependent fluid flow on tissue behavior at large strain-rates, which provides insights into the mechanical deformation mechanisms of cartilage tissues.
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The title compound, C16H18N2O2, is an important precursor in the synthesis of 1,2,3,4-tetrahydropyrazinoindoles, which show excellent antihistamine, antihypertensive and central nervous system depressant properties. The carbethoxy group attached to C2 and the planar cyanoethyl group attached to N1 make dihedral angles of 11.0(4) and 75.0(3)degrees, respectively, with the mean plane of the indole ring, The C-C=N chain is linear with a bond angle of 179.3 (4)degrees.
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A fuzzy waste-load allocation model, FWLAM, is developed for water quality management of a river system using fuzzy multiple-objective optimization. An important feature of this model is its capability to incorporate the aspirations and conflicting objectives of the pollution control agency and dischargers. The vagueness associated with specifying the water quality criteria and fraction removal levels is modeled in a fuzzy framework. The goals related to the pollution control agency and dischargers are expressed as fuzzy sets. The membership functions of these fuzzy sets are considered to represent the variation of satisfaction levels of the pollution control agency and dischargers in attaining their respective goals. Two formulations—namely, the MAX-MIN and MAX-BIAS formulations—are proposed for FWLAM. The MAX-MIN formulation maximizes the minimum satisfaction level in the system. The MAX-BIAS formulation maximizes a bias measure, giving a solution that favors the dischargers. Maximization of the bias measure attempts to keep the satisfaction levels of the dischargers away from the minimum satisfaction level and that of the pollution control agency close to the minimum satisfaction level. Most of the conventional water quality management models use waste treatment cost curves that are uncertain and nonlinear. Unlike such models, FWLAM avoids the use of cost curves. Further, the model provides the flexibility for the pollution control agency and dischargers to specify their aspirations independently.
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Guanylyl cyclase C (GCC), a member of the family of membrane bound guanylyl cyclases is the receptor for the heat-stable enterotoxin (ST) peptides and the guanylin family of endogenous peptides. GCC is activated upon ligand binding to increase intracellular cGMP levels, which in turn activates other downstream signalling events in the cell. GCC is also activated in vitro by nonionic detergents. We have used the T84 cell line as a model system to investigate the regulation of GCC activity by ATP. Ligand-stimulated GCC activity is potentiated in the presence of ATP, whereas detergent-stimulated activity is inhibited. The potentiation of GCC activity by ATP is dependent on the presence of Mg2+ ions, and is probably brought about by a direct binding of Mg-ATP to GCC. The protein kinase-like domain of GCC, which has earlier been shown to play a critical role in the regulation of GCC activity, may be a possible site for the binding of Mg-ATP to GCC.
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Neural data are inevitably contaminated by noise. When such noisy data are subjected to statistical analysis, misleading conclusions can be reached. Here we attempt to address this problem by applying a state-space smoothing method, based on the combined use of the Kalman filter theory and the Expectation–Maximization algorithm, to denoise two datasets of local field potentials recorded from monkeys performing a visuomotor task. For the first dataset, it was found that the analysis of the high gamma band (60–90 Hz) neural activity in the prefrontal cortex is highly susceptible to the effect of noise, and denoising leads to markedly improved results that were physiologically interpretable. For the second dataset, Granger causality between primary motor and primary somatosensory cortices was not consistent across two monkeys and the effect of noise was suspected. After denoising, the discrepancy between the two subjects was significantly reduced.
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The multiphoton inverse bremsstrahlung absorption of two intense electromagnetic beams passing through a magnetized plasma is studied. The rate of absorption of electromagnetic energy by the electrons is calculated by deriving a kinetic equation for the electrons. It is found that the absorption enhances when the frequency of one electromagnetic beam is more, and that of the other electromagnetic beam is less, than the electron-cyclotron frequency. A possible application to extragalactic radio sources is discussed.