731 research outputs found

    Topological properties of regular generalized function algebras

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    We investigate density of various subalgebras of regular generalized functions in the special Colombeau algebra of generalized functions.Comment: 6 page

    Distributional energy momentum tensor of the extended Kerr geometry

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    We generalize previous work on the energy-momentum tensor-distribution of the Kerr geometry by extending the manifold structure into the negative mass region. Since the extension of the flat part of the Kerr-Schild decomposition from one sheet to the double cover develops a singularity at the branch surface we have to take its non-smoothness into account. It is however possible to find a geometry within the generalized Kerr-Schild class that is in the Colombeau-sense associated to the maximally analytic Kerr-metric.Comment: 12 pages, latex2e, amslatex and epsf macro

    The use of D-chiro-inositol in clinical practice

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    OBJECTIVE: D-chiro-Inositol has been widely used in clinical practice to induce ovulation in women with polycystic ovary syndrome. Only recent evidence established that this molecule acts through two different mechanisms, with potentially different outcomes. On the one hand, under a metabolic perspective, D-chiro-Inositol improves insulin signaling, thus restoring physiological insulin levels in resistant subjects. On the other hand, at a cellular level, it downregulates the expression of steroidogenic enzyme aromatase, which is responsible for the conversion of androgens to estrogens. MATERIALS AND METHODS: We reviewed current literature in different databases, searching for D-chiro-Inositol in relation with one of the following keywords: myo-inositol, PCOS, infertility, insulin resistance, aromatase, androgen and inositol, testosterone, estrogen and inositol, estradiol, hypogonadotropic hypogonadism, fat tissue, estrogens and cancer, anovulation, uterine myoma, endometriosis, endometrial hyperplasia. RESULTS: D-Chiro-Inositol treatment may be helpful in restoring physiological hormonal levels in various clinical disorders. However, D-Chiro-Inositol intervention should be carefully designed to avoid possible undesired side effects stemming from its multiple mechanisms of action. CONCLUSIONS: We evaluated the optimal D Chiro-Inositol administration for different pathologies, defining dosages and timing. Even though further studies are required to validate our preliminary results, this paper is primarily intended to guide researchers through some of the pathways of D-Chiro-Inositol

    Total flow intensity, active flow intensity and volume related flow intensity as new quantitative metrics in optical coherence tomography angiography

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    Optical coherence tomography (OCT) angiography (OCTA) is a non-invasive tool for the in-vivo study of the intraretinal vascular network. It is based on the analysis of motion particles within the retina to reconstruct the paths followed by the erythrocytes, i.e. retinal capillaries. To date, qualitative and quantitative information are based on the morphological features disclosed by retinal capillaries. In the present study, we proposed new quantitative functional metrics, named Total Flow Intensity (TFI), Active Flow Intensity (AFI), and Volume-related Flow Intensity (VFI), based on the processing of the blood flow signal detected by OCTA. We studied these metrics in a cohort of healthy subjects, and we assessed their clinical utility by including a cohort of age-matched patients affected by Stargardt disease. Moreover, we compared TFI, AFI, and VFI to the widely used vessel density (VD) parameter. TFI, AFI, and VFI were able to describe in detail the different properties of the retinal vascular compartment. In particular, TFI was intended as the overall amount of volumetric retinal blood flow. AFI represented a selective measure of voxels disclosing blood flow signal. VFI was developed to put in relationship the volumetric blood flow information with the not vascularized retinal volume. In conclusion, TFI, AFI, and VFI were proposed as feasible functional OCTA biomarkers based on the analysis of retinal blood flow signal

    RENAL DENERVATION RAPIDLY RESTORES CIRCULATING PROGENITOR CELLS IN PATIENTS AFFECTED BY RESISTANT HYPERTENSION

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    Objective: To investigate whether blood pressure (BP) lowering after renal sympathetic denervation (RSD) affects CD34+ cell number in drug-resistant hypertension (R-HTN). Design and method: We enrolled 11 patients with R-HTN, already treated with at least 6 antihypertensive drugs, including a diuretic, at full dosages; patients with offi ce BP of > 160 mmHg (>150 mmHg for type 2 diabetes) were considered eligible for the procedure. Adherence to drug treatment was accurately checked by patient’s general practitioners. Mean age was 61 ± 7.9 years; M: F 8:5. We measured clinic (sphygmomanometer) and ambulatory (Tonoport V GEHealthcare) BP, and heart rate (HR; electrocardiogram), at baseline and 30 days after RSD procedure (Symplicity; Medtronic). 24 h BP recordings and home BP protocols were consulted in addition to offi ce BP measurements at the hospital before enrollment. Results: At T0: SBP: 179.1 ± 9.3mmHg; DBP: 101.2 ± 5.5 mmHg; HR 79.9 ± 9.4; CD34+ cells: 1.66 ± 0.51. At T1 SBP values were reduced on the average of 40.2 mmHg (138.9 ± 7.3; –22.5%, p < 0.001) DBP of 18 mmHg (83.2 ± 3.2; –17.7%, p < 0.001), and HR of 10.4 bpm (67.3 ± 6.0; -17.7%, p < 0.005), and CD34+cell number increased on an average of 0.34 cells /microL (2.0 ± 0.51; +21.2%, p < 0.001). Conclusions: RSD rapidly restores CD34+cell number in patients affected by true R-HTN; if these results will be confi rmed on a larger scale, they could provide new insights about CD34+ cells and pathophysiological aspects of arterial hypertension

    Extrafoveal Müller cells detection in vivo in the human retina: a pilot study based on optical coherence tomography

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    Müller cells (MC) represent a key element for the metabolic and functional regulation of the vertebrate retina. The aim of the present study was to test the feasibility of a new method for the in-vivo detection and quantification of extrafoveal MC in human retina. We developed a new approach to isolate and analyse extrafoveal MC in vivo, starting from structural optical coherence tomography data. Our pilot investigation was based on the optical properties of MC, which are known to not interfere with the light reaching the outer retinal structures. We reconstructed MC in the macular region of 18 healthy subjects and the quantitative analyses revealed ~42,000/9 mm2 cells detected. Furthermore, we included 2 patients affected by peripheral intraocular melanoma, with macular sparing, needing surgical enucleation. We used these two eyes to perform a qualitative comparison between our reconstructions and histological findings. Our study represents the first pilot investigation dedicated on the non-invasive isolation and quantification of MC, in-vivo, in human retina. Although we are aware that our study has several limitations, first of all related with the proper detection of foveal MC, because of the peculiar z-shape morphology, this approach may open new opportunities for the non-invasive in vivo analysis of MC, providing also potential useful perspectives in retinal diseases

    Hypoxia inducible factor-1 alpha expression is increased in infected positive HPV16 DNA oral squamous cell carcinoma and positively associated with HPV16 E7 oncoprotein

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    <p>Abstract</p> <p>Background</p> <p>There is increasing evidence for the role of High Risk (HR) Human PapillomaVirus (HPV) in the pathogenesis of Oral Squamous Cell Carcinoma (OSCC). The E6 and E7 oncogenes from HR HPVs are responsible for the deregulation of p53 and pRB proteins involved in cell cycle and apoptotic pathways. In cell lines experiments, the HPV E7 protein seems to be able to enhance Hypoxia Inducible Factor-1 alpha (HIF-1α) activity, normally involved in the response to hypoxia and able to enhance angiogenesis.</p> <p>Results</p> <p>We studied tumor specimens from 62 OSCC; a higher prevalence of tumors in TNM stage II and also in pT2 class between OSCC infected positive HPV16 DNA than non-infected ones was observed. HIF-1α positivity was detected throughout the analysed fields, not associated with areas of necrosis and also observed in cells immediately adjacent to blood vessels. A significant increase in mean values of the HIF-1α labeling indexes was observed for pT1-T2, as well for stage I-II, in the infected positive HPV16 DNA tumors than non-infected ones. HIF-1α and HPV16 E7 labeling indexes showed a significantly positive correlation which suggested a positive association between HPV16 E7 and HIF-1α expression.</p> <p>Conclusions</p> <p>In our specimens HIF-1α immunoreactivity hints for an O<sub>2</sub>-independent regulatory mechanism in infected positive HPV16 DNA tumors, especially for pT1-T2 and stage I-II tumors, suggesting a very early involvement in the development of HPV-induced OSCC. HIF-1α and HPV16 E7 labeling indexes suggest also a positive association between the two proteins in infected positive HPV16 DNA OSCC.</p

    Semi-invariants of symmetric quivers of finite type

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    Let (Q,σ)(Q,\sigma) be a symmetric quiver, where Q=(Q0,Q1)Q=(Q_0,Q_1) is a finite quiver without oriented cycles and σ\sigma is a contravariant involution on Q0Q1Q_0\sqcup Q_1. The involution allows us to define a nondegenerate bilinear form on a representation $V$ of $Q$. We shall call the representation orthogonal if is symmetric and symplectic if is skew-symmetric. Moreover we can define an action of products of classical groups on the space of orthogonal representations and on the space of symplectic representations. For symmetric quivers of finite type, we prove that the rings of semi-invariants for this action are spanned by the semi-invariants of determinantal type cVc^V and, in the case when matrix defining cVc^V is skew-symmetric, by the Pfaffians pfVpf^V

    Sub-clinical effects of chronic noise exposure on vestibular system

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    Aim: to investigate the effect of chronic noise exposure on vestibular function of subjects without clinical evidence of vestibular disorders and with documented cochlear damage from noise. Subjects and methods: 25 patients with chronic noise- induced hearing loss (NIHL) and without vestibular complaints (group A) and 25 matched controls with sensorineural hearing loss without noise exposure (group B), underwent audiological and vestibular test including caloric and cervical vestibular-evoked myogenic potentials tests (cVEMPs). Results: In subjects chronically exposed to noise, similarly to that of the auditory threshold, an increase in the evocation threshold of VEMPs has been documented, statistically significant (p&lt;0,05) and independent of the performance of the auditory threshold. p1-n1 amplitude values showed a significant difference between group A and group B. No significant difference for p1-n1 latencies between the two groups was found. Conclusion: We have documented the possibility of vestibular lesion, along with cochlear damage, related to chronic acoustic trauma

    Semi-invariants of symmetric quivers of tame type

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    A symmetric quiver (Q,σ)(Q,\sigma) is a finite quiver without oriented cycles Q=(Q0,Q1)Q=(Q_0,Q_1) equipped with a contravariant involution σ\sigma on Q0Q1Q_0\sqcup Q_1. The involution allows us to define a nondegenerate bilinear form on a representation $V$ of $Q$. We shall say that $V$ is orthogonal if is symmetric and symplectic if is skew-symmetric. Moreover, we define an action of products of classical groups on the space of orthogonal representations and on the space of symplectic representations. So we prove that if (Q,σ)(Q,\sigma) is a symmetric quiver of tame type then the rings of semi-invariants for this action are spanned by the semi-invariants of determinantal type cVc^V and, when matrix defining cVc^V is skew-symmetric, by the Pfaffians pfVpf^V. To prove it, moreover, we describe the symplectic and orthogonal generic decomposition of a symmetric dimension vector
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