2,336 research outputs found

    Opportunities and challenges of unplanned follow-up interviews: Experiences with Polish migrants in London

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    Although there is growing interest in qualitative longitudinal research as a way of taking time seriously (ADAM, 2000), this approach still holds many challenges for the social researcher. In this article we use a reflexive approach, drawing on a Goffmanian analysis of self-presentation, to consider our separate but related experience of re-interviewing Polish migrants over intervals of several years. In each case, the repeat interviews were not part of the original research design and were undertaken years later for a range of different reasons. After briefly presenting case studies from our individual interviews, we critically reflect upon some opportunities and challenges of researching change through time. We first consider the ways in which repeat interviews may challenge earlier analyses and findings. We then explore some of the ethical considerations involved in unplanned repeat interviews. Next, we reflect upon dilemmas about self-revelation, particularly in contexts of social media and on-line technologies. Finally, we discuss what we have learned from our different experiences and what implications there are for this kind of ad hoc longitudinal research in migration studies

    Characterization of hair-follicle side population cells in mouse epidermis and skin tumors.

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    A subset of cells, termed side-population (SP), which have the ability to efflux Hoeschst 33342, have previously been demonstrated to act as a potential method to isolate stem cells. Numerous stem/progenitor cells have been localized in different regions of the mouse hair follicle (HF). The present study identified a SP in the mouse HF expressing the ABCG2 transporter and MTS24 surface marker. These cells are restricted to the upper isthmus of the HF and have previously been described as progenitor cells. Consistent with their SP characteristic, they demonstrated elevated expression of ABCG2 transporter, which participates in the dye efflux. Analysis of tumor epidermal cell lines revealed a correlation between the number of SP keratinocytes and the grade of malignancy, suggesting that the SP may play a role in malignant progression. Consistent with this idea, the present study observed an increased number of cells expressing ABCG2 and MTS24 in chemically induced skin tumors and skin tumor cell lines. This SP does not express the CD34 surface marker detected in the multipotent stem cells of the bulge region of the HF, which have been defined as tumor initiation cells. The present study concluded that a SP with properties of progenitor cells is localized in the upper isthmus of the HF and is important in mouse skin tumor progression

    Cyclin D3 deficiency inhibits skin tumor development, but does not affect normal keratinocyte proliferation.

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    Rearrangement and amplification of the D-type cyclin genes have been reported in human cancer. Previous studies have demonstrated that Ras-mediated skin tumorigenesis depends on pathways that act through cyclin D1 and D2; however, the role of cyclin D3 remains unknown. The present study demonstrates that cyclin D3 ablation does not affect keratinocyte proliferation, but instead increases apoptosis levels in the bulge region of the hair follicle. Consequently, cyclin D3 ablation reduces skin papilloma development in a Ras-dependent carcinogenesis model. Previous results revealed that cyclin D3 preferentially binds to cyclin-dependent kinase 6 (CDK6) in mouse keratinocytes and transgenic expression of CDK6 (K5CDK6 mice) inhibits skin tumor development. Thus, we hypothesized that the inhibitory effect of CDK6 is dependent on cyclin D3 expression. To test this hypothesis, a mouse model that overexpresses CDK6 and does not express cyclin D3 (K5CDK6/cyclin D3-/- compound mouse) was developed. Biochemical analysis of the epidermis of K5CDK6/cyclin D3-/- mice revealed that cyclin D3 ablation resulted in increased expression of cyclin D1 protein, with a consequent elevation in the level of CDK6/cyclin D1 and CDK4/cyclin D1 complexes. These findings were concurrent with the increase skin papilloma malignant progression observed in K5CDK6/cyclin D3-/- mice. In summary the absence of cyclin D3 led to fewer number of papillomas in cyclin D3-ablated mice than in the wild-type owing to increased apoptosis, suggesting that alterations in cell survival are a crucial mechanism for crippling cellular defense against neoplasia. The results of the current study also suggest that although cyclin D3 expression does not alter the tumor suppressive role of CDK6 in skin carcinogenesis, the compensatory increase in cyclin D1 can shift the balance towards malignant progression

    Politicas agrarias y estrategias campesinas en la Cuenca del Canete : anexos 8 a 13

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    Ce document réunit plusieurs diagnostics établis à partir d'observations de terrain sur la géographie physique, l'organisation sociale, les pratiques paysannes dans la vallée de Canete et la vallée Pampas afin de déterminer les facteurs limitants de la production et des pratiques culturales , notamment en matière d'irrigation

    Final state effects on superfluid 4^{\bf 4}He in the deep inelastic regime

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    A study of Final State Effects (FSE) on the dynamic structure function of superfluid 4^4He in the Gersch--Rodriguez formalism is presented. The main ingredients needed in the calculation are the momentum distribution and the semidiagonal two--body density matrix. The influence of these ground state quantities on the FSE is analyzed. A variational form of ρ2\rho_2 is used, even though simpler forms turn out to give accurate results if properly chosen. Comparison to the experimental response at high momentum transfer is performed. The predicted response is quite sensitive to slight variations on the value of the condensate fraction, the best agreement with experiment being obtained with n0=0.082n_0=0.082. Sum rules of the FSE broadening function are also derived and commented. Finally, it is shown that Gersch--Rodriguez theory produces results as accurate as those coming from other more recent FSE theories.Comment: 20 pages, RevTex 3.0, 11 figures available upon request, to be appear in Phys. Rev.

    Aprovechamiento de residuos de la industria textil para la preparación de telas de carbón activo.

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    Los residuos generados por la industria textil en España se han cuantificado sobre unas 30.000 Toneladas durante los últimos años. Debido al gran volumen de almacenamiento que necesitan estos residuos, así como la problemática generada por la disponibilidad geográfica, hacen que sea de gran interés el estudio del aprovechamiento de estos materiales, siendo de gran importancia la obtención de materiales carbonosos que poseen originariamente una estructura fibrilar en forma continua, cuya forma presenta características muy interesantes para distintas aplicaciones. En el presente trabajo se muestran los resultados de preparación y caracterización de materiales carbonosos a partir de residuos de la industria textil, usando como materia prima tejidos de algodón, los cuales se activarán químicamente con H3PO4. Las telas de carbón activo obtenidas serán usadas para testar su aplicación como adsorbentes y como materiales para almacenamiento de energía.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

    Immunotherapeutic targeting of LIGHT/LTβR/HVEM pathway fully recapitulates the reduced cytotoxic phenotype of LIGHT-deficient T cells.

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    Tumor necrosis factor (TNF)/TNF receptor (TNFR) superfamily members play essential roles in the development of the different phases of the immune response. Mouse LIGHT (TNFSF14) is a type II transmembrane protein with a C-terminus extracellular TNF homology domain (THD) that assembles in homotrimers and regulates the course of the immune responses by signaling through 2 receptors, the herpes virus entry mediator (HVEM, TNFSFR14) and the lymphotoxin β receptor (LTβR, TNFSFR3). LIGHT is a membrane-bound protein transiently expressed on activated T cells, natural killer (NK) cells and immature dendritic cells that can be proteolytically cleaved by a metalloprotease and released to the extracellular milieu. The immunotherapeutic potential of LIGHT blockade was evaluated in vivo. Administration of an antagonist of LIGHT interaction with its receptors attenuated the course of graft-versus-host reaction and recapitulated the reduced cytotoxic activity of LIGHT-deficient T cells adoptively transferred into non-irradiated semiallogeneic recipients. The lack of LIGHT expression on donor T cells or blockade of LIGHT interaction with its receptors slowed down the rate of T cell proliferation and decreased the frequency of precursor alloreactive T cells, retarding T cell differentiation toward effector T cells. The blockade of LIGHT/LTβR/HVEM pathway was associated with delayed downregulation of interleukin-7Rα and delayed upregulation of inducible costimulatory molecule expression on donor alloreactive CD8 T cells that are typical features of impaired T cell differentiation. These results expose the relevance of LIGHT/LTβR/HVEM interaction for the potential therapeutic control of the allogeneic immune responses mediated by alloreactive CD8 T cells that can contribute to prolong allograft survival
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