303 research outputs found
Up-date on sun protection factor
No full textThe sun protection factor (SPF) refers to the level of protection of a sunscreen against UV rays and is expressed, according to the COLIPA recommendation as a numerical value, and in terms of low, medium, high, and very high protection as well. For the determination of SPF exist methods in vivo (on volunteers) and in vitro (laboratory tests on artificial substrates). At European level there is a standard method for the determination of “in vivo” SPF: "International Sun Protection Factor Test Method " and a standard method to determine the “in vitro” UVA-PF: “Method for “in vitro” Determination of UVA protection " published by COLIPA in 2006 and 2011 respectively. There is still no definitive and optimized procedure to analyze the “in vitro” SPF. In this work, it was assessed the influence of substrate type and amount of product applied on the determination of “in vitro” SPF. The measurements were carried out with two instruments: Labsphere UV 1000S and UV 2000S, in order to assess their equivalence for such determinations. The study also focused on the evaluation of UVA-PF on several commercially available substrates. With the two instruments it is possible to get results “in vitro” correlate with those “in vivo” for low and medium SPF, while for high values of SPF some problems may occur. We compared SPF “in vivo” values with those measured “in vitro”. From all analyses we were able to point out that, as regards SPF determination the Transpore is an excellent substrate for the “in vitro” determination excluding alcoholic or high lipophilic preparations. Values even more similar to those “in vivo” were obtained with two different types of PMMA having same roughness (Ra). With regard to the UVA-PF two different roughness of PMMA were tested .The best results were obtained with the PMMA of Ra: 4.8. Of all the emulsions tested it was obtained a value of UVA-PF exceeding 1/3 of SPF calculated in vivo
Disentangling the solar activity-solar wind predictive causality at Space Climate scales
No full textThe variability in the magnetic activity of the Sun is the main source of the
observed changes in the plasma and electromagnetic environments within the
heliosphere. The primary way in which solar activity affects the Earth's
environment is via the solar wind and its transients. However, the relationship
between solar activity and solar wind is not the same at the Space Weather and
Space Climate time scales. In this work, we investigate this relationship
exploiting five solar cycles data of Ca II K index and solar wind parameters,
by taking advantage of the Hilbert-Huang Transform, which allows to separate
the contribution at the different time scales. By filtering out the high
frequency components and looking at decennial time scales, we confirm the
presence of a delayed response of solar wind to Ca II K index variations, with
a time lag of ~ 3.1-year for the speed and ~ 3.4-year for the dynamic pressure.
To assess the results in a stronger framework, we make use of a Transfer
Entropy approach to investigate the information flow between the quantities and
to test the causality of the relation. The time lag results from the latter are
consistent with the cross-correlation ones, pointing out the presence of a
statistical significant information flow from Ca II K index to solar wind
dynamic pressure that peaks at time lag of 3.6-year. Such a result could be of
relevance to build up a predictive model in a Space Climate context
Nerve growth factor expression in human dystrophic muscles
No full textNerve growth factor (NGF) is a neurotrophin that is expressed during muscle development and is also capable of favoring muscle regeneration in experimental studies. The presence of NGF in muscular dystrophies, such as Duchenne and Becker muscular dystrophies, has never been fully explored. By means of immunohistochemistry, we show that regenerating muscle fibers from such patients consistently express NGF, as do myofibroblasts and mast cells. By contrast, rest fibers from dystrophic patients, as well as muscle fibers from healthy, control patients and even regenerative muscle fibers in polymyositis do not show NGF immunoreactivity. The paracrine effect of NGF on muscle regeneration, as well as its chemoattractant capacities for mast cells, may contribute to explaining why regenerating fibers most frequently occur in clusters and why mast cells are more numerous in dystrophic muscles. Moreover, being a mediator of wound healing and tissue fibrosis, NGF may contribute to long-term muscle regeneration impairment by tissue fibrosis in the muscular dystrophies
sylvae parvae: poems
No full textThe following is a collection of original poetry, supplemented by a critical introduction tracing biographical, literary, and theoretical influences. The critical introduction takes the form of a series of loosely connected notes. The poems are divided into two major sections.
I begin by discussing the difficulties involved in writing an overarching introduction to a collection which was never intended to be a cohesive whole, that is to say, a group of individual poems rather than a themed collection or sequence. I examine some of the influences on my work, including other poets and authors. These poets do not fall into strictly defined schools or chronological periods. Rather, I find that certain poets throughout history pay attention in greater or lesser detail to the spaces around words (potential meanings) and the system that is constructed in a given poem. I align myself, therefore, not with particular schools or eras, but with writing styles. I also discuss some of the theories that come into play in my work. Most often these resemble postmodernism, yet I tend to draw on metaphors from science or philosophy rather than literary theorists themselves, who are often needlessly obtuse. Lastly, I look at autobiographical influences that have shaped my writing. I complete my introduction with a detailed discussion of two poems and how these various elements are visible therein, and a few comments on the title of the thesis.
The first section of poetry is titled "Lyrics & Observations." As can be gleaned from this title, the poetry is primarily lyric, though alternating between formal and informal in structure. Additionally, most of the lyric poems I write tend to make observations on life, leaving any moral unspoken or open-ended. The second section of poetry, on the other hand, is titled "Narratives & Lessons" and tends towards poetry with an overt message.
These poems represent a selected output of the last year. Some of the poems may have begun their lives before I began my studies at Texas A&M University, but almost all have been revised since that point, reflecting my continuing growth and change as a writer
Cell composition and immunohistochemical detection of VEGF, TGF-ß and TNF-α in proliferative vitreoretinopathy
No full textFormation of vascularized membranes inside the vitreous leads to retinal detachment and blindness. In this paper it is shown that vitreal membranes are composed of newly formed vessels and myofibroblasts, immersed in a loose stroma with sparse histocytes. Vascular endothelial growth factor (VEGF) is clearly present in cellular constituents of the membranes and, therefore, represents a fundamental cytokine in their formation, while transforming growth factor-beta (TGF-beta) and tumor necrosis factor-alpha (TNF-alpha) are not. Considering that the composition of vitreal membranes clearly resembles scar tissue, the absence of TGF-beta in the membranes could explain their peculiar histological appearance
Histology of anterior capsule fibrosis following phacoemulsification
No full textPURPOSE:
To determine the histology and immunohistochemistry of anterior capsule fibrosis.
SETTING:
Department of Ophthalmology and Neurosurgery and Institute of Pathology, University of Siena, Siena, Italy.
METHODS:
Tissue sections from 3 patients with anterior capsule fibrosis after phacoemulsification and intraocular lens implantation were examined histologically.
RESULTS:
The proliferating tissue was devoid of vessels and composed of dense fibrous tissue and numerous activated fibroblasts with contractile capacity (myofibroblasts). No TGF-beta, which is the most important cytokine in modulating myofibroblasts, was present in the fibrotic tissue.
CONCLUSION:
The absence of the cytokine TGF-beta and inflammatory cells in the proliferating tissue confirms the unique character of the reparative activity within the eye
Preliminary Validation and Sensitivity Analysis on a Eulerian/Lagrangian RANS Approach for Liquid Injection in Supersonic Crossflow
No full textPhysical phenomena related to liquid jets in supersonic crossflows are fundamental for several applications in the aerospace propulsion field. A preliminary validation of a Eulerian- Lagrangian RANS-CFD is conducted on a testcase employing water injection in a M=1.94 crossflow with a jet-to-freestream momentum flux ratio q=7. After presenting the numerical models, the effect of turbulence is investigated by performing simulations using the RNG k-ε, Menter SST k-ω, and Reynolds Stress Model (RSM), retaining the breakup sub-model constants at their default values. A sensitivity analysis is then conducted by varying some parameters of the latter, highlighting a greater influence of the parameter associated with the critical breakup radius in the Kelvin-Helmholtz model. The results show that the differences between the various turbulence closure models are minimal in this configuration. The consistency of the results with the physics of the problem is critically reviewed, revealing some discrepancies compared to experimental data in terms of liquid presence on the wall and trends in the Sauter mean diameter and velocity along the penetration direction coordinate. A calibration procedure for the k-ω model is proposed, based on fitting the obtained data and the maximum expected SMD. The calibrated simulation shows improved results in terms of agreement with penetration height, SMD and particle velocity
Small thymus in very low birth weight infants born to mothers with subclinical chorioamnionitis
No full textChorioamnionitis, a major cause of preterm birth with significant neonatal
morbidity and mortality, frequently occurs in mothers who are free of
symptoms. A combined clinical, radiologic, and pathologic study of 129
very low birth weight infants indicated a significant association between a
markedly decreased thymic size at birth and subclinical chorioamnionitis
Scarring in papillary carcinoma of the thyroid: report of two new cases with exuberant nodular fasciitis-like stroma. Histopathology
No full textAims: To describe two new cases of papillary carcinoma of the thyroid with exuberant nodular fasciitis-like stroma, one of which was characterized by previously unreported transformation into a poorly differentiated lesion. Moreover, we explore the presence of TGF-β to help to clarify the pathogenesis of the collagen formation. Methods and results: The case characterized by an aggressive behaviour exhibited areas of transformation into a poorly differentiated (insular) carcinoma of the thyroid. In both cases, as revealed by immunohistochemistry, neoplastic cells produced and secreted high amounts of TGF-β. On the contrary, TGF-β immunoreaction was never present in the normal thyroid or in papillary carcinomas without collagen bundles, while a weak, exclusively intracellular reaction was present in a patchy manner in cases showing intratumoral fibrous bundles. Conclusions: The rare variant of papillary thyroid carcinoma characterized by exuberant stroma may give rise to more aggressive lesions, as do other histotypes of differentiated thyroid carcinomas. TGF-β, the fundamental cytokine which mediates scarring and activation of myofibroblasts, most probably induces the exuberant stroma
Spleen depletion in neonatal sepsis and chorioamnionitis
No full textNeonatal sepsis and chorioamnionitis induce morphologic modifications and shrinkage of the thymus. We show fetal and neonatal morphologic modifications of the spleen in the same autopsy subjects as previously used to describe thymus shrinkage, including 10 preterm or full-term neonates who died of proven sepsis within 48 hours after birth and 20,fetuses spontaneously aborted because of extensive ascending chorioamnionitis. Control subjects included 10 fetuses from induced termination of pregnancy and 10 neonates who died suddenly during the perinatal period without evidence of chorioamnionitis. Spleen cell populations were studied by means of immunohistochemical analysis. Neonatal sepsis occurred with severe spleen depletion, involving both B and T lymphocytes (P < .001). Fetuses with chorioamnionitis also showed spleen cell depletion. These observations, to our knowledge not described before, indicate that preterm and term neonates show an inflammatory reaction similar to that of adult patients and that severe chorioamnionitis is associated with a nonspecific inflammatory response comparable to that of sepsis
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