2,985 research outputs found

    Elastic anomalies in glasses: the string theory understanding in the case of Glycerol and Silica

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    We present an implementation of the analytical string theory recently applied to the description of glasses. These are modeled as continuum media with embedded elastic string heterogeneities, randomly located and randomly oriented, which oscillate around a straight equilibrium position with a fundamental frequency depending on their length. The existence of a length distribution reflects then in a distribution of oscillation frequencies which is responsible for the Boson Peak in the glass density of states. Previously, it has been shown that such a description can account for the elastic anomalies reported at frequencies comparable with the Boson Peak. Here we start from the generalized hydrodynamics to determine the dynamic correlation function S(k,ω)S(k,\omega) associated with the coherent, dispersive and attenuated, sound waves resulting from a sound-string interference. Once the vibrational density of states has been measured, we can use it for univocally fixing the string length distribution inherent to a given glass. The density-density correlation function obtained using such distribution is strongly constrained, and able to account for the experimental data collected on two prototypical glasses: glycerol and silica. The obtained string length distribution is compatible with the typical size of elastic heterogeneities previously reported for silica and supercooled liquids, and the atomic motion associated to the string dynamics is consistent with the soft modes recently identified in large scale numerical simulations as non-phonon modes responsible for the Boson Peak. The theory is thus in agreement with the most recent advances in the understanding of the glass specific dynamics and offers an appealing simple understanding of the microscopic origin of the latter, while raising new questions on the universality or material-specificity of the string distribution properties.Comment: 15 pages, 8 figure

    Effetti immunomodulatori di preparazioni fitoterapiche a base di Echinacea

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    In questa tesi ho analizzato studi in vitro ed in vivo sugli effetti immunomodulatori di preparazioni contenenti Echinacea purpurea, Echinacea pallida ed Echinacea angustifolia. Sulla base dei risultati ottenuti con gli studi in vivo, per il momento non è possibile affermare se le specie di Echinacea abbiano proprietà immunomodulatorie. I risultati di numerosi trials sono ottenuti con tecniche disomogenee, pertanto risulta impossibile comarare i risultati emersi dagli studi. Anche gli studi in vitro sull' attività immunomodulatoria dell' Echinacea hanno mostrato risultati controversi, mentre altri studi sulla sua attività antinfiammatoria propongono le alcamidi come una nuova classe di cannabinomimetici. This thesis analyzes in vivo and in vitro studies about remedies containing Echinacea purpurea, Echinacea pallida and Echinacea angustifolia. At present it's not possible to affirm if Echinacea species have immunomodulatory properties. Various trials results come from not univocal methods and so it is impossible to compare each other. In vitro studies also show controversial results about immunomodulatory activity of Echinacea species. Other in vitro studies show an interesting cannabinomimetic effect from Echinacea's alcamides

    Lattice and string worldsheet in AdS/CFT: a numerical study

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    We consider a possible discretization for the gauge-fixed Green-Schwarz (two-dimensional) sigma-model action for the Type IIB superstring and use it for measuring the cusp anomalous dimension of planar N=4\mathcal{N}=4 SYM as derived from string theory. We perform lattice simulations employing a Rational Hybrid Monte Carlo (RHMC) algorithm and a Wilson-like fermion discretization. In this preliminary study, we compare our results with the expected behavior for very large values of g=λ4πg=\frac{\sqrt{\lambda}}{4\pi}, which is the perturbative regime of the sigma-model, and find a qualitative agreement at finite lattice spacing. For smaller gg the continuum limit is obstructed by a divergence. We also detect a phase in the fermion determinant, whose origin we explain, which for small gg leads to a sign problem not treatable via standard reweigthing. Results presented here are discussed thoroughly in~\cite{toappear}.Comment: Contribution to the proceedings of Lattice 2015, July 14--18, Kobe, Japa

    Preimplantation biopsy predicts delayed graft function, glomerular filtration rate and long-term graft survival of transplanted kidneys

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    Background The predictive value of preimplantation biopsies for long-term graft function is often limited by conflicting results. The aim of this study was to evaluate the influence of time-zero graft biopsy histological scores on early and late graft function, graft survival and patient survival, at different time points. Methods We retrospectively analyzed 284 preimplantation biopsies at a single center, in a cohort of recipients with grafts from live and deceased donors (standard and nonstandard), and their impact in posttransplant renal function after a mean follow-up of 7 years (range 1–16). Implantation biopsy score (IBS), a combination score derived from 4 histopathological aspects, was determined from each sample. The correlation with incidence of delayed graft function (DGF), creatinine clearance (1st, 3rd and 5th posttransplant year) and graft and patient survival at 1 and 5 years were evaluated. Results Preimplantation biopsies provided somewhat of a prognostic index of early function and outcome of the transplanted kidney in the short and long term. In the immediate posttransplantation period, the degree of arteriolosclerosis and interstitial fibrosis correlated better with the presence of DGF. IBS values between 4 and 6 were predictive of worst renal function at 1st and 3rd years posttransplant and 5-year graft survival. The most important histological finding, in effectively transplanted grafts, was the grade of interstitial fibrosis. Patient survival was not influenced by IBS. Conclusions Higher preimplantation biopsy scores predicted an increased risk of early graft losses, especially primary nonfunction. Graft survival (at 1st and 5th years after transplant) but not patient survival was predicted by IBS

    Gene-specific methylation profiles in BRCA-mutation positive and BRCA-mutation negative male breast cancers

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    Male breast cancer (MBC) is a rare disease. Due to its rarity, MBC research and clinical approach are mostly based upon data derived from female breast cancer (FBC). Increasing evidence indicate that on molecular level MBC may be an heterogeneous disease different from FBC. In order to investigate whether epigenetic signatures could define molecular subgroups of MBCs, we performed promoter methylation analysis of genes involved in signal transduction and hormone signalling in BRCA1/2 mutation-positive and -negative MBCs. We examined 69 MBCs, paired blood samples, and 15 normal tissues for promoter methylation of hTERT, ESR1, RASSF1, AR, MYC and WNT1 genes. MBCs showed higher gene promoter methylation levels compared to paired blood and normal breast samples. Significantly higher RASSF1 methylation levels were observed in association with BRCA1/2 mutations, HER2 expression and high tumor grade. Significantly higher AR methylation levels were observed in BRCA1/2 wild-type cases and higher WNT1 methylation levels in PR negative cases. Overall, our results indicate that alterations in gene methylation profiles are common in MBC and that methylation pattern of tumor-associated genes may allow for the identification of MBC molecular subgroups, that could have implications in clinical management of MBC patients

    Patient safety competencies in undergraduate nursing students: a rapid evidence assessment

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    Aims To identify patient safety competencies, and determine the clinical learning environments that facilitate the development of patient safety competencies in nursing students. Background Patient safety in nursing education is of key importance for health professional environments, settings, and care systems. To be effective, safe nursing practice requires a good integration between increasing knowledge and the different clinical practice settings. Nurse educators have the responsibility to develop effective learning processes and ensure patient safety. Design Rapid Evidence Assessment. Data Sources MEDLINE, CINAHL, SCOPUS, and ERIC were searched, yielding 500 citations published between 1 January 2004 - 30 September 2014. Review Methods Following the Rapid Evidence Assessment process, 17 studies were included in this review. Hawker's (2002) quality assessment tool was used to assess the quality of the selected studies. Results Undergraduate nursing students need to develop competencies to ensure patient safety. The quality of the pedagogical atmosphere in the clinical setting has an important impact on the students’ overall level of competence. Active student engagement in clinical processes stimulates their critical reasoning, improves interpersonal communication, and facilitates adequate supervision and feedback. Conclusion Few studies describe the nursing students’ patient safety competencies and exactly what they need to learn. In addition, studies describe only briefly which clinical learning environments facilitate the development of patient safety competencies in nursing students. Further research is needed to identify additional pedagogical strategies and the specific characteristics of the clinical learning environments that encourage the development of nursing students’ patient safety competencies

    Cervical carcinogenesis, bacterial vaginosis, HPV-mRNA test and relapse of CIN2+ after loop electrosurgical excision procedure (LEEP)

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    OBJECTIVE: The aim of the study was to evaluate the relationship between bacterial vaginosis (BV) and relapse of cervical intraepithelial neoplasia grade 2 or more (CIN2+) after Loop electrosurgical excision procedure (LEEP). PATIENTS AND METHODS: One hundred four patients who underwent LEEP for CIN2+ were followed up every six months for three years. Fifty-three were negative for BV and fifty-one were positive. Each clinical control included Pap test, colposcopy, Amsel criteria test, HPV-DNA, and HPV-mRNA test. RESULTS: Patients’ age, presence of BV, positivity to HPV-DNA and HPV-mRNA tests were analyzed. The average age of patients was 42.5 ± 8.92 years (median: 42.5; range from 27 to 58 years). The minimum follow-up was 6 months and maximum 36 months (average: 22.8 ± 4.53; median: 24). The 10% of the patients with HPV-mRNA test negative had relapsed, compared to 45% of patients with HPV-mRNA test positive. Among the 53 patients without BV the 20% had relapsed compared with 23% of 51 patients with diagnosis of BV. CONCLUSIONS: There is no evidence for higher percentage of relapse in patients with BV, submitted to excisional procedure for CIN2+ associated to HPV-m-RNA test positivity. There is only a correlation among BV and relapse of CIN2+ lesions after LEEP

    Operator Product Expansion for Pure Spinor Superstring on AdS(5)*S(5)

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    The tree-level operator product expansion coefficients of the matter currents are calculated in the pure spinor formalism for type IIB superstring in the AdS(5)*S(5) background.Comment: 18 pages, no figure, corrected typos and added acknowledgement

    HDAC4 regulates satellite cell proliferation and differentiation by targeting P21 and Sharp1 genes

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    Skeletal muscle exhibits a high regenerative capacity, mainly due to the ability of satellite cells to replicate and differentiate in response to appropriate stimuli. Epigenetic control is effective at different stages of this process. It has been shown that the chromatin-remodeling factor HDAC4 is able to regulate satellite cell proliferation and commitment. However, its molecular targets are still uncovered. To explain the signaling pathways regulated by HDAC4 in satellite cells, we generated tamoxifen-inducible mice with conditional inactivation of HDAC4 in Pax7(+) cells (HDAC4 KO mice). We found that the proliferation and differentiation of HDAC4 KO satellite cells were compromised, although similar amounts of satellite cells were found in mice. Moreover, we found that the inhibition of HDAC4 in satellite cells was sufficient to block the differentiation process. By RNA-sequencing analysis we identified P21 and Sharp1 as HDAC4 target genes. Reducing the expression of these target genes in HDAC4 KO satellite cells, we also defined the molecular pathways regulated by HDAC4 in the epigenetic control of satellite cell expansion and fusion
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