8,639 research outputs found

    Matrix metalloproteinases-2,-3,-7,-9 and-10, but not MMP-11, are differentially expressed in normal, benign tumorigenic and malignant human keratinocyte cell lines

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    In order to investigate the correlations between constitutive proteinase expression and the degree of tumorigenicity of cancer cells we have studied a model system of three keratinocyte cell lines. RT-PCR studies showed that the cell lines express the genes of matrix metalloproteinase-2, -3, -7, -9, -10 and -11, indicating that they are able to synthesize the corresponding enzymes. Actual MMP synthesis was proven by zymography and Western blotting. In conditioned media gelatinolytic activities or immunoreactive forms of MMP-2, -3, -7, -9, -10 and -11 were detected. The signal intensities showed that MMP secretion increases in the order HaCaT < A5 less than or equal to II-4RT, whereas only MMP-11 is secreted by all cell lines in equal amounts, Intracellularly, enhanced levels of one or both of the tumorigenic variants were only found for MMP-3 -9 and -10, suggesting special functions of these intracellular MMP pools for the tumorigenic cell lines. For MMP-11 exclusive expression in stromal fibroblasts of tumor tissues is widely accepted; however, our results and three other recent reports demonstrate that this concept is not generally valid. In conclusion, the three keratinocyte cell lines investigated here represent an excellent model for studying constitutive expression and secretion of MMPs in correlation to the degree of in vivo tumorigenicity

    Spectroscopic Observations of New Oort Cloud Comet 2006 VZ13 and Four Other Comets

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    Spectral data are presented for comets 2006 VZ13 (LINEAR), 2006 K4 (NEAT), 2006 OF2 (Broughton), 2P/Encke, and 93P/Lovas I, obtained with the Cerro-Tololo Inter-American Observatory 1.5-m telescope in August 2007. Comet 2006 VZ13 is a new Oort cloud comet and shows strong lines of CN (3880 angstroms), the Swan band sequence for C_2 (4740, 5160, and 5630 angstroms), C_3 (4056 angstroms), and other faint species. Lines are also identified in the spectra of the other comets. Flux measurements of the CN, C_2 (Delta v = +1,0), and C_3 lines are recorded for each comet and production rates and ratios are derived. When considering the comets as a group, there is a correlation of C_2 and C_3 production with CN, but there is no conclusive evidence that the production rate ratios depend on heliocentric distance. The continuum is also measured, and the dust production and dust-to-gas ratios are calculated. There is a general trend, for the group of comets, between the dust-to-gas ratio and heliocentric distance, but it does not depend on dynamical age or class. Comet 2006 VZ13 is determined to be in the carbon-depleted (or Tempel 1 type) class.Comment: 8 pages, 6 figures, 6 tables; Accepted by MNRA

    Unpacking the associations between heterogeneous externalising symptom development and academic attainment in middle childhood

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    This study explores children’s externalising symptom development pathways between 8 and 11 years of age (three time points across 2 years) and examines their sociodemographic correlates and associations with change in academic attainment. Externalising symptoms were assessed for 5485 children across three consecutive years (Mage = 8.7 years, SD = 0.30 at time 1). National standardised test scores served as an index of academic attainment. Using latent class growth analysis, six distinct trajectories of externalising symptom development were identified. Children who showed increasing externalising symptomatology across the three time points were more likely to be male or have special educational needs. These derived trajectories differentially predicted children’s subsequent academic attainment (controlling for earlier attainment). Children with increasing externalising symptomatology were significantly more likely to demonstrate negative change in academic achievement compared with children with consistently low externalising problems. The study helps to clarify the longitudinal association between externalising symptom development and academic attainment, and highlights the importance of early intervention for children with increasing externalising symptoms across middle childhoo

    Biochemistry and functional aspects of human glandular kallikreins

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    Human urinary kallikrein was purified by gel filtration on Sephacryl S-200 and affinity chromatography on aprotinin-Sepharose, followed by ion exchange chromatography on DEAE-Sepharose. In dodecylsulfate gel electrophoresis two protein bands with molecular weights of 41,000 and 34,000 were separated. The amino acid composition and the carbohydrate content of the kallikrein preparation were determined; isoleucine was identified as the only aminoterminal amino acid. The bimolecular velocity constant for the inhibition by diisopropyl fluorophosphate was determined as 9±2 l mol–1 min–1. The hydrolysis of a number of substrates was investigated and AcPheArgOEt was found to be the most sensitive substrate for human urinary kallikrein. Using this substrate an assay method for kallikrein in human urine was developed. It was shown by radioimmunoassay that pig pancreatic kallikrein can be absorbed in the rat intestinal tract. Furthermore, in dogs the renal excretion of glandular kallikrein from blood was demonstrated by radioimmunological methods

    School characteristics and children's mental health: A linked survey-administrative data study

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    Mental health difficulties are childhood-onset with lifelong health, social and economic consequences. Children spend a large amount of time in schools, making schools an important context for mental health prevention and support. We examine how school composition and school climate, controlling for individual child-level characteristics, are associated with children's mental health difficulties (emotional and behavioural difficulties). Data from 23,215 children from 648 primary schools in England were analysed to examine the associations of school composition (size, gender, socioeconomic and ethnicity) and school climate with mental health (emotional symptoms, behavioural symptoms and above clinical cut-off scores) adjusting for individual child socio-demographic characteristics. We find that between 3% and 4.5% of the variation in children's mental health outcomes could be attributed to schools. Of this, small proportions were explained by school composition (1.4 to 3.8%) and larger proportions were explained by school climate (29.5 to 48.8%). Lower school socio-economic status was associated with higher behavioural symptoms (coef = 0.02 [95%CI: 0.01–0.04]) and slightly raised odds of high mental health difficulties (OR = 1.05, 95% CI: 1.01,1.09). More positive school climate was associated with lower emotional (coef = −0.09 [95%CI:-0.11,-0.08]) and behavioural (coef = −0.13 [95% CI,-0.15:-0.11]) symptoms and lower odds of mental health difficulties (OR = 0.78, 95%CI:0.74,0.81). Some associations between school factors and mental health were moderated by child sex and SES. School composition factors were weakly associated with children's mental health, whereas school climate explained a larger amount of between-school variation and appears a good target for universal prevention of mental health difficulties in children

    Applying weighted network measures to microarray distance matrices

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    In recent work we presented a new approach to the analysis of weighted networks, by providing a straightforward generalization of any network measure defined on unweighted networks. This approach is based on the translation of a weighted network into an ensemble of edges, and is particularly suited to the analysis of fully connected weighted networks. Here we apply our method to several such networks including distance matrices, and show that the clustering coefficient, constructed by using the ensemble approach, provides meaningful insights into the systems studied. In the particular case of two data sets from microarray experiments the clustering coefficient identifies a number of biologically significant genes, outperforming existing identification approaches.Comment: Accepted for publication in J. Phys.

    Stationary Entangled Radiation from Micromechanical Motion

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    Mechanical systems facilitate the development of a new generation of hybrid quantum technology comprising electrical, optical, atomic and acoustic degrees of freedom. Entanglement is the essential resource that defines this new paradigm of quantum enabled devices. Continuous variable (CV) entangled fields, known as Einstein-Podolsky-Rosen (EPR) states, are spatially separated two-mode squeezed states that can be used to implement quantum teleportation and quantum communication. In the optical domain, EPR states are typically generated using nondegenerate optical amplifiers and at microwave frequencies Josephson circuits can serve as a nonlinear medium. It is an outstanding goal to deterministically generate and distribute entangled states with a mechanical oscillator. Here we observe stationary emission of path-entangled microwave radiation from a parametrically driven 30 micrometer long silicon nanostring oscillator, squeezing the joint field operators of two thermal modes by 3.40(37) dB below the vacuum level. This mechanical system correlates up to 50 photons/s/Hz giving rise to a quantum discord that is robust with respect to microwave noise. Such generalized quantum correlations of separable states are important for quantum enhanced detection and provide direct evidence for the non-classical nature of the mechanical oscillator without directly measuring its state. This noninvasive measurement scheme allows to infer information about otherwise inaccessible objects with potential implications in sensing, open system dynamics and fundamental tests of quantum gravity. In the near future, similar on-chip devices can be used to entangle subsystems on vastly different energy scales such as microwave and optical photons.Comment: 13 pages, 5 figure

    Child- and school-level predictors of children's bullying behavior: A multilevel analysis in 648 primary schools

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    © 2017 American Psychological Association. A great deal of bullying behavior takes place at school, however, existing literature has predominantly focused on individual characteristics of children associated with bullying with less attention on schoollevel factors. The current study, comprising 23,215 children (51% boys) recruited from Year 4 or Year 5 (M = 9.06 years, SD = .56 years) from 648 primary schools in England, aimed to examine the independent and combined influence of child- and school-level predictors on bullying behavior in primary school. Children provided information on bullying behavior and school climate. Demographic characteristics of children were obtained from the National Pupil Database, and demographic characteristics of schools were drawn from EduBase. Multilevel logistic regression models showed that individual child gender, ethnicity, deprivation and special educational needs status all predicted bullying behavior. Of the school-level predictors, only overall school deprivation and school climate were predictive of bullying behavior once child-level predictors were taken into account. There was a significant interaction between child- and school-level deprivation; high-deprivation schools were a risk factor for bullying only for children that came from nondeprived backgrounds, whereas deprived children reported engaging in bullying behavior irrespective of school-level deprivation. Given the independent and combined role of child- and school-level factors for bullying behavior, the current study has implications for targeted school interventions to tackle bullying behavior, both in terms of identifying high-risk children and identifying high-risk schools

    A Comparison of Stripe Modulations in La1.875_{1.875}Ba0.125_{0.125}CuO4_4 and La1.48_{1.48}Nd0.4_{0.4}Sr0.12_{0.12}CuO4_4

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    We report combined soft and hard x-ray scattering studies of the electronic and lattice modulations associated with stripe order in La1.875_{1.875}Ba0.125_{0.125}CuO4_4 and La1.48_{1.48}Nd0.4_{0.4}Sr0.12_{0.12}CuO4_4. We find that the amplitude of both the electronic modulation of the hole density and the strain modulation of the lattice is significantly larger in La1.875_{1.875}Ba0.125_{0.125}CuO4_4 than in La1.48_{1.48}Nd0.4_{0.4}Sr0.12_{0.12}CuO4_4 and is also better correlated. The in-plane correlation lengths are isotropic in each case; for La1.875_{1.875}Ba0.125_{0.125}CuO4_4, ξhole=255±5\xi^{hole}=255\pm 5 \AA\ whereas for La1.48_{1.48}Nd0.4_{0.4}Sr0.12_{0.12}CuO4_4F, ξhole=111±7\xi^{hole}=111\pm 7 \AA. We find that the modulations are temperature independent in La1.875_{1.875}Ba0.125_{0.125}CuO4_4 in the low temperature tetragonal phase. In contrast, in La1.48_{1.48}Nd0.4_{0.4}Sr0.12_{0.12}CuO4_4, the amplitude grows smoothly from zero, beginning 13 K below the LTT phase transition. We speculate that the reduced average tilt angle in La1.875_{1.875}Ba0.125_{0.125}CuO4_4 results in reduced charge localization and incoherent pinning, leading to the longer correlation length and enhanced periodic modulation amplitude.Comment: 6 pages, 4 figure
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