252 research outputs found
Versatile lithium fluoride thin-film solid-state detectors for nanoscale radiation imaging
Point defects in insulating materials are successfully used for radiation detectors. Among them, colour centres in lithium fluoride (LiF) are well known for application in dosimeters and in light-emitting devices and lasers. LiF
thin-film detectors for extreme ultraviolet radiation, soft and hard X-rays, based on photoluminescence from aggregate electronic defects, are currently under development for imaging application with laboratory radiation sources, e.g. laser-driven plasma sources and conventional X-ray tubes, as well as large-scale facilities, e.g. synchrotrons and free-electron lasers. Among the peculiarities of these detectors, noteworthy ones are the very high intrinsic spatial resolution ( 1 cm2) and the wide dynamic range. Moreover, they are insensitive to ambient light and no development process is needed. The latent images stored in the LiF thin layer can be read with fluorescence optical microscopy techniques.
These detectors prove to be highly versatile, as LiF is sensitive to almost any kind of radiation, including charged particles and neutrons, and can be grown in the form of polycrystalline thin films, whose photoluminescence response can be tailored trough the control of the growth conditions
Photoluminescence of radiation-induced color centers in lithium fluoride thin films for advanced diagnostics of proton beams
Systematic irradiation of thermally evaporated 0.8 μm thick polycrystalline lithium fluoride films on glass was performed by proton beams of 3 and 7 MeV energies, produced by a linear accelerator, in a fluence range from 1011 to 1015 protons/cm2. The visible photoluminescence spectra of radiation-induced F2 and F3+ laser active color centers, which possess almost overlapping absorption bands at about 450 nm, were measured under laser pumping at 458 nm. On the basis of simulations of the linear energy transfer with proton penetration depth in LiF, it was possible to obtain the behavior of the measured integrated photoluminescence intensity of proton irradiated LiF films as a function of the deposited dose. The photoluminescence signal is linearly dependent on the deposited dose in the interval from 103 to about 106 Gy, independently from the used proton energies. This behavior is very encouraging for the development of advanced solid state radiation detectors based on optically transparent LiF thin films for proton beam diagnostics and two-dimensional dose mapping
Pentacyclic triterpenes from Terminalia arjuna show multiple benefits on aged and dry skin
BACKGROUND Pentacyclic triterpenoids improve epidermal barrier function and induce collagen production. Here, their effects on cutaneous aging by means of objective instrumental measurements were elucidated. METHODS Reconstituted human epidermis, cultivated keratinocytes and fibroblasts were incubated with Terminalia arjuna triterpenes (T. arjuna bark extract), and mRNA and protein expression of various genes was determined using microarray analysis, qRT-PCR and ELISA techniques. Clinical efficacy of T. arjuna bark extract versus vehicle control cream was elucidated in 30 patients and transepidermal water loss (TEWL), skin hydration and elasticity were measured. Another 30 female patients in their postmenopausal phase were treated with a similar regime, and skin sebum content, cutaneous blood microcirculation and skin density/echogenicity were assessed. RESULTS Incubation with T. arjuna triterpenes increased FGF-2, TSP-1, TGF-\textgreekb and CTGF expression, and VEGF secretion in vitro. Elevated lactate dehydrogenase release upon sodium dodecyl sulphate challenge was reversed by the application of T. arjuna bark extract. T. arjuna bark extract decreased TEWL, improved skin moisturization, reduced scaliness and led to significantly improved skin elasticity. Also, increases in blood microflow and skin sebum content as well as improved skin thickness/echogenicity were noted on postmenopausal skin, resulting in visible reduction of sagging skin on the jowls as demonstrated by digital photography. CONCLUSION T. arjuna bark extract appears as an innovative active ingredient that exerts versatile antiaging properties in vitro and in vivo
Amphibian transition to the oxidant terrestrial environment affects the expression of glutathione S-transferases isoenzymatic pattern
AbstractIt has been postulated that glutathione S-transferases (GST; EC 2.5.1.18) may play a role in protecting against oxidative stress.In previous studies, we have purified and characterised from Bufo bufo embryos a GST isoenzyme (BbGSTP1-1), which falls at very low level in the adult liver, where a novel isoform (BbGSTP2-2), starts to be highly expressed. During transition to adult life, B. bufo leaves the aquatic environment to live predominantly in the terrestrial environment, characterised by higher oxygen concentration.It has been found that BbGSTP2-2 is more efficient in scavenging from organic hydroperoxides.Therefore, the appearance of BbGSTP2-2 may respond to the necessity of providing the adult toad with a more suitable protection against oxygen toxic by-products. In this work, we performed experiments aimed at verifying if oxidative stress (hyperoxic and H2O2 treatments) could act as a modulator of BbGSTP2-2 expression. Results show that: (a) BbGSTP2 mRNA starts to be expressed in the late embryonic period, while protein appears during metamorphosis; (b) oxidative stress induces anticipation of BbGSTP2 gene expression at both transcriptional and translational levels.These findings seem to indicate that the appearance of BbGSTP2-2 is aimed at endowing the adult toad with more efficient antioxidant defence in the terrestrial atmosphere
Contact X-ray microscopy of living cells by using LiF crystal as imaging detector
In this paper, the use of lithium fluoride (LiF) as imaging
radiation detector to analyse living cells by single-shot soft
X-ray contact microscopy is presented. High resolved X-ray
images on LiF of cyanobacterium Leptolyngbya VRUC135,
two unicellular microalgae of the genus Chlamydomonas
and mouse macrophage cells (line RAW 264.7) have been
obtained utilizingX-ray radiation in the water window energy
range from a laser plasma source. The used method is based on
loading of the samples, the cell suspension, in a special holder
where they are in close contactwith a LiF crystal solid-state Xray
imaging detector. After exposure and sample removal, the
images stored in LiF by the softX-ray contactmicroscopy technique
are read by an optical microscope in fluorescence mode.
The clear image of the mucilaginous sheath the structure
of the filamentous Leptolyngbya and the visible nucleolus in
the macrophage cells image, are noteworthiness results. The
peculiarities of the used X-ray radiation and of the LiF imaging
detector allow obtaining images in absorption contrast revealing
the internal structures of the investigated samples at high
spatial resolution. Moreover, thewidedynamicrangeof theLiF
imaging detector contributes to obtain high-quality images. In
particular, we demonstrate that this peculiar characteristic of
LiF detector allows enhancing the contrast and reveal details
even when they were obscured by a nonuniform stray light
Evidences of +896 A/G TLR4 Polymorphism as an Indicative of Prevalence of Complications in T2DM Patients
T2DMis today considered as world-wide health problem, with complications responsible of an enhanced mortality and morbidity.
Thus, new strategies for its prevention and therapy are necessary. For this reason, the research interest has focused its attention
on TLR4 and its polymorphisms, particularly the rs4986790. However, no conclusive findings have been reported until now about
the role of this polymorphism in development of T2DM and its complications, even if a recent meta-analysis showed its T2DM
association in Caucasians. In this study, we sought to evaluate the weight of rs4986790 polymorphism in the risk of the major
T2DMcomplications, including 367 T2DMpatients complicated for the 55.6%. Patients with A/A and A/G TLR4 genotypes showed
significant differences in complication\u2019s prevalence. In particular, AG carriers had higher risk prevalence for neuropathy (P =
0.026), lower limb arteriopathy (P = 0.013), and the major cardiovascular pathologies (P = 0.017). Their cumulative risk was
significant (P = 0.01), with a threefold risk to develop neuropathy, lower limb arteriopathy, and major cardiovascular events in AG
cases compared to AA cases.The adjusted OR for the confounding variables was 3.788 (95% CI: 1.642\u20138.741).Thus, the rs4986790
polymorphism may be an indicative of prevalence of complications in T2DM patients
High resolution and high efficiency coloration of lithium fluoride by soft X-rays irradiation
The efficient coloration of LiF material, in the form of bulk and films, by EUV and soft X-rays emitted by a laser-plasma source is demonstrated. The short penetration depth of soft-X-rays is exploited to obtain high spatial resolution luminescent patterns while the high dynamic range of proportionality between X-ray dose and coloration is exploited for using LiF as image detector in micro-radiography and soft X-ray microscopy applications
Erythropoietin (EPO) haplotype associated with all-cause mortality in a cohort of Italian patients with Type-2 Diabetes
Type-2 Diabetes (T2D), diabetic complications, and their clinical risk factors harbor a substantial genetic component but the genetic factors contributing to overall diabetes mortality remain unknown. Here, we examined the association between genetic variants at 21 T2D-susceptibility loci and all-cause mortality in an elderly cohort of 542 Italian diabetic patients who were followed for an average of 12.08 years. Univariate Cox regression analyses detected age, waist-to-hip ratio (WHR), glycosylated haemoglobin (HbA1c), diabetes duration, retinopathy, nephropathy, chronic kidney disease (CKD), and anaemia as predictors of all-cause mortality. When Cox proportional hazards multivariate models adjusted for these factors were run, three erythropoietin (EPO) genetic variants in linkage disequilibrium (LD) with each other (rs1617640-T/G, rs507392-T/C and rs551238-A/C) were significantly (False Discovery Rate < 0.1) associated with mortality. Haplotype multivariate analysis revealed that patients carrying the G-C-C haplotype have an increased probability of survival, while an opposite effect was observed among subjects carrying the T-T-A haplotype. Our findings provide evidence that the EPO gene is an independent predictor of mortality in patients with T2D. Thus, understanding the mechanisms by which the genetic variability of EPO affects the mortality of T2D patients may provide potential targets for therapeutic interventions to improve the survival of these patients
Hair Strengthening Evaluation of Anisotropic Osmolite Solutions (Inositol + Arginine): Cross-Talk between Dermal Papilla Fibroblast and Keratinocytes of the Outer Root Sheath Using a µHair Follicle 3D Model
The hair follicle (HF) is a dynamic \u201cmini-organ\u201d which undergoes bi-continuous cycles of growth, destruction and rest. The molecular mechanisms underlying the HF cycle are complex yet not fully understood. Anyhow, it is clear that the epithelial\u2013mesenchymal interactions, and in particular the cross-talk between dermal papilla fibroblast (DPF) and the keratinocytes of the outer root sheath (ORSK) play a pivotal role. Aim of this study is the evaluation of the biological activity of
anisotropic osmolyte solutions on the HF cycle. As reported in recent studies, dermal papilla cells deeply modify their gene expression profile when cultured as monolayers, but their transcriptional pattern can be partially restored when they are cultured as 3-dimensional spheroids. This draws our attention to the discovery that the spatial distribution of cells in the growth medium is fundamental in order to produce a verisimilar model. Therefore, we used the hanging drop technology to produce a scaffold-free micro-tissue model applied to a DPF-ORSK co-culture in order to create a \u3bcHF 3-dimensional model. As a result, this system was capable of evaluating the efficacy of the anisotropic osmolyte solutions on the progressive increase of the follicle turnover and \u2018health\u2019. Moreover, an in silico model was used in order to screen the most promising combination of osmolyte molecules. In vivo objective evaluations were finally carried out on volunteers having hair disorders
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