662 research outputs found

    Quantitative uniqueness for elliptic equations with singular lower order terms

    Full text link
    We use a Carleman type inequality of Koch and Tataru to obtain quantitative estimates of unique continuation for solutions of second order elliptic equations with singular lower order terms. First we prove a three sphere inequality and then describe two methods of propagation of smallness from sets of positive measure.Comment: 23 pages, v2 small changes are done and some mistakes are correcte

    Multiple genome relationships and a complex biogeographic history in the eastern range of Quercus suber L. (Fagaceae) implied by nuclear and chloroplast DNA variation

    Get PDF
    The complex evolutionary history of Quercus suber has been throughly investigated in many recent works, but the details of its differentiation processes are still largely unknown. In addition, the geographical and evolutionary roles of the eastern parts of the species range have gained much less attention compared to other southern European areas. In order to fill this gap, new insights to infer the species diversification and range establishment of the cork oak in the east-central Mediterranean are here provided by means of inter- and intra-specific plastid DNA and nuclear ribosomal ITS phylogeographic studies. We analyzed 95 natural cork oak populations; 6 closely related, sympatric oaks were included in the study and used for comparisons.Evidence for a clear phylogeographical structure was detected with PCR-RFLP at 5 chloroplast loci, while ITS sequence variation is apparently unrelated with the geographical distribution. Five chloroplast haplotypes and three ITS main lineages were identified. Three haplotypes and all ITS lineages occur in the Italian Peninsula, stressing the importance of these territories for the evolutionary history of the species. Two divergent "Italian" haplotypes are highly shared, and one ITS variant is basal to the ingroup, revealing sister relationships within Cerris taxonomic group. Hypotheses of hybridization, lineage sorting of ancient DNA polymorphisms and of reticulate evolution of the whole species group are presented and discussed

    Lineage relationship of prostate cancer cell types based on gene expression

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>Prostate tumor heterogeneity is a major factor in disease management. Heterogeneity could be due to multiple cancer cell types with distinct gene expression. Of clinical importance is the so-called cancer stem cell type. Cell type-specific transcriptomes are used to examine lineage relationship among cancer cell types and their expression similarity to normal cell types including stem/progenitor cells.</p> <p>Methods</p> <p>Transcriptomes were determined by Affymetrix DNA array analysis for the following cell types. Putative prostate progenitor cell populations were characterized and isolated by expression of the membrane transporter ABCG2. Stem cells were represented by embryonic stem and embryonal carcinoma cells. The cancer cell types were Gleason pattern 3 (glandular histomorphology) and pattern 4 (aglandular) sorted from primary tumors, cultured prostate cancer cell lines originally established from metastatic lesions, xenografts LuCaP 35 (adenocarcinoma phenotype) and LuCaP 49 (neuroendocrine/small cell carcinoma) grown in mice. No detectable gene expression differences were detected among serial passages of the LuCaP xenografts.</p> <p>Results</p> <p>Based on transcriptomes, the different cancer cell types could be clustered into a luminal-like grouping and a non-luminal-like (also not basal-like) grouping. The non-luminal-like types showed expression more similar to that of stem/progenitor cells than the luminal-like types. However, none showed expression of stem cell genes known to maintain stemness.</p> <p>Conclusions</p> <p>Non-luminal-like types are all representatives of aggressive disease, and this could be attributed to the similarity in overall gene expression to stem and progenitor cell types.</p

    The stability for the Cauchy problem for elliptic equations

    Full text link
    We discuss the ill-posed Cauchy problem for elliptic equations, which is pervasive in inverse boundary value problems modeled by elliptic equations. We provide essentially optimal stability results, in wide generality and under substantially minimal assumptions. As a general scheme in our arguments, we show that all such stability results can be derived by the use of a single building brick, the three-spheres inequality.Comment: 57 pages, review articl

    Changes in circulating microRNA levels associated with prostate cancer

    Get PDF
    BACKGROUND: The aim of this study was to investigate the hypothesis that changes in circulating microRNAs (miRs) represent potentially useful biomarkers for the diagnosis, staging and prediction of outcome in prostate cancer. METHODS: Real-time polymerase chain reaction analysis of 742 miRs was performed using plasma-derived circulating microvesicles of 78 prostate cancer patients and 28 normal control individuals to identify differentially quantified miRs. RESULTS: A total of 12 miRs were differentially quantified in prostate cancer patients compared with controls, including 9 in patients without metastases. In all, 11 miRs were present in significantly greater amounts in prostate cancer patients with metastases compared with those without metastases. The association of miR-141 and miR-375 with metastatic prostate cancer was confirmed using serum-derived exosomes and microvesicles in a separate cohort of patients with recurrent or non-recurrent disease following radical prostatectomy. An analysis of five selected miRs in urine samples found that miR-107 and miR-574-3p were quantified at significantly higher concentrations in the urine of men with prostate cancer compared with controls. CONCLUSION: These observations suggest that changes in miR concentration in prostate cancer patients may be identified by analysing various body fluids. Moreover, circulating miRs may be used to diagnose and stage prostate cance

    Tumor immunosurveillance in human cancers

    Get PDF
    Until now, the anatomic extent of tumor (TNM classification) has been by far the most important factor to predict the prognosis of colorectal cancer patients. However, in recent years, data collected from large cohorts of human cancers demonstrated that the immune contexture of the primary tumors is an essential prognostic factor for patients’ disease-free and overall survival. Tumoral and immunological markers predicted by systems biology methods are involved in the shaping of an efficient immune reaction and can serve as targets for novel therapeutic approaches. Global analysis of tumor microenvironment showed that the nature, the functional orientation, the density, and the location of adaptive immune cells within distinct tumor regions influence the risk of relapse events. The density and the immune cell location within the tumor have a prognostic value that is superior to the TNM classification, and tumor invasion is statistically dependent on the host-immune reaction. Thus, the strength of the immune reaction could advance our understanding of cancer evolution and have important consequences in clinical practice

    Prostate cancer cells modulate osteoblast mineralisation and osteoclast differentiation through Id-1

    Get PDF
    Background: Id-1 is overexpressed in and correlated with metastatic potential of prostate cancer. The role of Id-1 in this metastatic process was further analysed. Methods: Conditioned media from prostate cancer cells, expressing various levels of Id-1, were used to stimulate pre-osteoclast differentiation and osteoblast mineralisation. Downstream effectors of Id-1 were identified. Expressions of Id-1 and its downstream effectors in prostate cancers were studied using immunohistochemistry in a prostate cancer patient cohort (N110). Results: We found that conditioned media from LNCaP prostate cancer cells overexpressing Id-1 had a higher ability to drive osteoclast differentiation and a lower ability to stimulate osteoblast mineralisation than control, whereas conditioned media from PC3 prostate cancer cells with Id-1 knockdown were less able to stimulate osteoclast differentiation. Id-1 was found to negatively regulate TNF-Β and this correlation was confirmed in human prostate cancer specimens (P0.03). Furthermore, addition of recombinant TNF-Β to LNCaP Id-1 cell-derived media blocked the effect of Id-1 overexpression on osteoblast mineralisation. Conclusion: In prostate cancer cells, the ability of Id-1 to modulate bone cell differentiation favouring metastatic bone disease is partially mediated by TNF-Β, and Id-1 could be a potential therapeutic target for prostate cancer to bone metastasis. © 2010 Cancer Research UK. All rights reserved.link_to_OA_fulltex

    Quantitative estimates of unique continuation for parabolic equations, determination of unknown time-varying boundaries and optimal stability estimates

    Full text link
    In this paper we will review the main results concerning the issue of stability for the determination unknown boundary portion of a thermic conducting body from Cauchy data for parabolic equations. We give detailed and selfcontained proofs. We prove that such problems are severely ill-posed in the sense that under a priori regularity assumptions on the unknown boundaries, up to any finite order of differentiability, the continuous dependence of unknown boundary from the measured data is, at best, of logarithmic type

    Predicting site index from climate and soil variables for cork oak (Quercus suber L.) stands in Portugal

    Get PDF
    Site productivity, assessed through site index, was modelled using partial least squares regression as a function of soil and climatic variables. Two alternative models were developed: a full model, considering all available explanatory variables, and a reduced model, considering only variables that can be obtained without digging a soil pit. The reduced model was used for mapping the site index distribution in Portugal, on the basis of existing digital cartography available for the whole country. The developed models indicate the importance of water availability and soil water holding capacity for site index value distribution. Site index was related to climate, namely evaporation and frost, and soil characteristics such as lithology, soil texture, soil depth, thickness of the A horizon and soil classification. The variability of the estimated values within the map (9.5–16.8 m with an average value of 13.4 m) reflects the impact of soil characteristics on the site productivity estimation. These variables should be taken into consideration during the establishment of new plantations of cork oak, and management of existing plantations. Results confirm the potential distribution of cork oak in coastal regions. They also suggest the existence of a considerable area, located both North and South of the Tagus river, where site indices values of medium (]13;15]) to high (]15;17]) productivity classes may be expected. The species is then expected to be able to have good productivity along the northern coastal areas of Portugal, where presently it is not a common species but where, according to historical records, it occurred until the middle of the sixteenth century. The present research focused on tree growth. Cork growth and cork quality distribution needs to be further researched through the establishment of long term experimental sites along the distribution area of cork oak, namely in the central and northern coastal areas of the countryinfo:eu-repo/semantics/publishedVersio
    corecore