180 research outputs found
Monitoring of stress distribution in damaged small-scale masonry walls by using two innovative sensors
Structural Health Monitoring (SHM) represents a strategic solution for the preservation of cultural heritage buildings. Existing masonry structures often suffer reductions in mechanical performances due to physiological aging of material constituents, external actions, and effect of catastrophic natural events. In many cases, the prompt prediction of damage in masonry elements is difficult and it can cause sudden collapses, compromising the safety of people.
The proposed experimental study examines the effectiveness of two low-cost and innovative stress sensors, i.e. piezoelectric and capacitive stress sensors, for SHM of masonry structures. To this scope, the sensors were embedded in the mortar joints of two small-scale clay brick and calcarenite masonry wall specimens consisting of three panels. Experimental tests were carried out by applying a constant vertical compressive load at the top of each specimen and simulating the damage with a progressive reduction of the cross-section of one of the panels. During the tests, the vertical stress distributions (and their variations), were monitored by the sensors. Experimental outcomes from sensor reading were then compared to that numerically provided by a refined finite element simulation of the test. Results will show that vertical stress variations in masonry structures can be effectively accounted by the adopted sensors and potentially interpreted for the early prediction of structural damage
Identification of a serum and urine extracellular vesicle signature predicting renal outcome after kidney transplant
Background A long-standing effort is dedicated towards the identification of biomarkers allowing the prediction of graft outcome after kidney transplant. Extracellular vesicles (EVs) circulating in body fluids represent an attractive candidate, as their cargo mirrors the originating cell and its pathophysiological status. The aim of the study was to investigate EV surface antigens as potential predictors of renal outcome after kidney transplant. Methods We characterized 37 surface antigens by flow cytometry, in serum and urine EVs from 58 patients who were evaluated before, and at 10-14 days, 3 months and 1 year after transplant, for a total of 426 analyzed samples. The outcome was defined according to estimated glomerular filtration rate (eGFR) at 1 year. Results Endothelial cells and platelets markers (CD31, CD41b, CD42a and CD62P) in serum EVs were higher at baseline in patients with persistent kidney dysfunction at 1 year, and progressively decreased after kidney transplant. Conversely, mesenchymal progenitor cell marker (CD1c, CD105, CD133, SSEEA-4) in urine EVs progressively increased after transplant in patients displaying renal recovery at follow-up. These markers correlated with eGFR, creatinine and proteinuria, associated with patient outcome at univariate analysis and were able to predict patient outcome at receiver operating characteristics curves analysis. A specific EV molecular signature obtained by supervised learning correctly classified patients according to 1-year renal outcome. Conclusions An EV-based signature, reflecting the cardiovascular profile of the recipient, and the repairing/regenerative features of the graft, could be introduced as a non-invasive tool for a tailored management of follow-up of patients undergoing kidney transplant
Reticular Pseudodrusen in Early Age-Related Macular Degeneration Are Associated With Choroidal Thinning
PURPOSE. To compare choroidal thickness (CT) measurements in early AMD between patients with and without reticular pseudodrusen (RPD) using spectral-domain optical coherence tomography (SD-OCT). METHODS. This cross-sectional study examined 84 age-and sex-matched AMD patients (40 RPD [63 eyes], 44 non-RPD [75 eyes]). Fundus photographs and scanning laser ophthalmoscopy images were graded to identify RPD and non-RPD groups by three retinal specialists (MO, SY, SB) who were masked to corresponding SD-OCTs. CT at the fovea and 2400 to 3000 lm superior and inferior to the fovea was measured on SD-OCT by a grader (AG) and reviewed by a retinal specialist (SB). Only images with a clear posterior choroidal margin were analyzed (six eyes excluded due to poor image quality), and enhanced depth imaging SD-OCT was used when available (20 of 138 eyes). Greatest retinal thickness (RT) on horizontal foveal SD-OCT was also recorded. RESULTS. Mean CTs in the superior, foveal, and inferior macula in RPD (191.3 lm 6 57.9 SD, 176.3 lm 6 60.5 SD, 179.7 lm 6 56.24 SD) were significantly less than that of non-RPD (228.0 lm 6 66.1 SD, 216.5 lm 6 70.3 SD, 224.4 lm 6 71.9 SD; P ¼ 0.0010, P ¼ 0.0005, P ¼ 0.0001, respectively), as was greatest RT (P ¼ 0.0301). CONCLUSIONS. CT was thinner throughout the macula in the RPD group as compared with the non-RPD group. The current analysis supports an association between RPD and a thinned choroidal layer and is consistent with a choroidal etiology of RPD. CT may be integral to understanding RPD, and may be helpful in stratifying AMD progression risk. Keywords: reticular pseudodrusen, spectral-domain optical coherence tomography, choroidal layer, early age-related macular degeneration, retinal ischemia A ge-related macular degeneration is the leading cause of vision loss in developing and developed countries, 1 and accounts for more than 54% of all blindness in the United States. 2 Age-related macular degeneration is a disease characterized by extracellular material, collectively described as drusen, which accumulates under the RPE. Reticular pseudodrusen (RPD) are found in the fundus of some patients with AMD and were initially characterized as a peculiar yellow pattern occurring in the outer macula best visible under blue light in photographs of patients with AMD. 3 RPD have been associated with a higher likelihood of developing late AMD in the forms of choroidal neovascularization (CNV) 4-9 and geographic atrophy (GA). 10 However, there is no clear agreement about the prevalence of RPD, the relationship between RPD and AMD, 11 or the underlying etiology of RPD. Theories proposed for the etiology of RPD include abnormal choroidal perfusion, subretinal drusenoid deposits (SDD), or a combination of both. RPD have been associated with choroidal vascular abnormalities. A histopathologic study of one RPD eye found that there was a loss of the inner and middle layers of the choroid, subsequently leading to fibrous replacement of choroidal stroma. In normal eyes, the choroidal layer has been found to be thickest in the subfoveal region, where visual acuity and the concentration of cone photoreceptors are highest, with progressive thinning outward in both the horizontal and vertical axes
ATM Gene Variants in Patients with Idiopathic Perifoveal Telangiectasia
PURPOSE. To investigate the prevalence of sequence variants in the ATM gene and to determine the frequency of major agerelated macular degeneration (AMD)-associated variants in CFH, CFB, and 10q26 loci in patients with idiopathic perifoveal telangiectasia (IPT). METHODS. Thirty patients with diagnoses of IPT underwent standard ophthalmologic evaluation that included visual acuity testing, fundus photography, and fluorescein angiography. DNA was screened for variations in the ATM gene by a combination of denaturing high-performance liquid chromatography and direct sequencing. Major AMD-associated alleles in CFH, CFB, and 10q loci were screened by PCR-restriction fragment-length polymorphism. RESULTS. Nineteen female and 11 male patients (average age, 59 years) with a median visual acuity of 20/50 were evaluated. Six patients were of Asian-Indian origin, one was Hispanic, and 23 were of European-American ancestry. Nine of 30 (30%) patients had diabetes mellitus, 18 of 30 (60%) patients had hypertension, and 12 of 30 (40%) patients had a history of smoking. Screening of the ATM gene revealed a null allele in 2 of 23 (8.7%) patients of European ancestry, previously disease-associated missense alleles in 4 of 23 (17.4%) patients, and common missense alleles in 7 of 23 (30.4%) patients. No variants were identified in the ATM gene in patients of Asian or Hispanic origin. Frequencies of major AMD-associated alleles in CFH, CFB, and 10q loci in the IPT cohort were similar to those in the ethnically matched general population. CONCLUSIONS. At least 26%, and maybe up to 57%, of IPT patients of European-American descent carried possibly diseaseassociated ATM alleles. Vascular risk factors such as hypertension, diabetes, and smoking may be associated with the pathogenesis of the disease. (Invest Ophthalmol Vis Sci. 2008; 49:3806 -3811
Comprehensive Analysis of the Candidate Genes CCL2, CCR2, and TLR4 in Age-Related Macular Degeneration
PURPOSE. To determine whether variants in the candidate genes TLR4, CCL2, and CCR2 are associated with age-related macular degeneration (AMD). METHODS. This study was performed in two independent Caucasian populations that included 357 cases and 173 controls from the Netherlands and 368 cases and 368 controls from the United States. Exon 4 of the TLR4 gene and the promoter, all exons, and flanking intronic regions of the CCL2 and CCR2 genes were analyzed in the Dutch study and common variants were validated in the U.S. study. Quantitative (q)PCR reactions were performed to evaluate expression of these genes in laserdissected retinal pigment epithelium from 13 donor AMD and 13 control eyes. RESULTS. Analysis of single nucleotide polymorphisms (SNPs) in the TLR4 gene did not show a significant association between D299G or T399I and AMD, nor did haplotypes containing these variants. Univariate analyses of the SNPs in CCL2 and CCR2 did not demonstrate an association with AMD. For CCR2, haplotype frequencies were not significantly different between cases and controls. For CCL2, one haplotype containing the minor allele of C35C was significantly associated with AMD (P ϭ 0.03), but this did not sustain after adjustment for multiple testing (q ϭ 0.30). Expression analysis did not demonstrate altered RNA expression of CCL2 and CCR2 in the retinal pigment epithelium from AMD eyes (for CCL2 P ϭ 0.62; for CCR2 P ϭ 0.97). CONCLUSIONS. No evidence was found of an association between TLR4, CCR2, and CCL2 and AMD, which implies that the common genetic variation in these genes does not play a significant role in the etiology of AMD. (Invest Ophthalmol Vis Sci
The ERCC6 Gene and Age-Related Macular Degeneration
Background: Age-related macular degeneration (AMD) is the leading cause of irreversible visual loss in the developed countries and is caused by both environmental and genetic factors. A recent study (Tuo et al., PNAS) reported an association between AMD and a single nucleotide polymorphism (SNP) (rs3793784) in the ERCC6 (NM_000124) gene. The risk allele also increased ERCC6 expression. ERCC6 is involved in DNA repair and mutations in ERCC6 cause Cockayne syndrome (CS). Amongst others, photosensitivity and pigmentary retinopathy are hallmarks of CS. Methodology/Principal Findings: Separate and combined data from three large AMD case-control studies and a prospective population-based study (The Rotterdam Study) were used to analyse the genetic association between ERCC6 and AMD (2682 AMD cases and 3152 controls). We also measured ERCC6 mRNA levels in retinal pigment epithelium (RPE) cells of healthy and early AMD affected human donor eyes. Rs3793784 conferred a small increase in risk for late AMD in the Dutch population (The Rotterdam and AMRO-NL study), but this was not replicated in two non-European studies (AREDS, Columbia University). In addition, the AMRO-NL study revealed no significant association for 9 other variants spanning ERCC6. Finally, we determined that ERCC6 expression in the human RPE did not depend on rs3793784 genotype, but, interestingly, on AMD status: Early AMD-affected donor eyes had a 50% lower ERCC6 expression than healthy donor eyes (P = 0.018). Conclusions/Significance: Our meta analysis of four Caucasian cohorts does not replicate the reported association between SNPs in ERCC6 and AMD. Nevertheless, our findings on ERCC6 expression in the RPE suggest that ERCC6 may be functionally involved in AMD. Combining our data with those of the literature, we hypothesize that the AMD-related reduced transcriptional activity of ERCC6 may be caused by diverse, small and heterogeneous genetic and/or environmental determinants
Common variants near FRK/COL10A1 and VEGFA are associated with advanced age-related macular degeneration
Despite significant progress in the identification of genetic loci for age-related macular degeneration (AMD), not all of the heritability has been explained. To identify variants which contribute to the remaining genetic susceptibility, we performed the largest meta-analysis of genome-wide association studies to date for advanced AMD. We imputed 6 036 699 single-nucleotide polymorphisms with the 1000 Genomes Project reference genotypes on 2594 cases and 4134 controls with follow-up replication of top signals in 5640 cases and 52 174 controls. We identified two new common susceptibility alleles, rs1999930 on 6q21-q22.3 near FRK/COL10A1 [odds ratio (OR) 0.87; P = 1.1 × 10−8] and rs4711751 on 6p12 near VEGFA (OR 1.15; P = 8.7 × 10−9). In addition to the two novel loci, 10 previously reported loci in ARMS2/HTRA1 (rs10490924), CFH (rs1061170, and rs1410996), CFB (rs641153), C3 (rs2230199), C2 (rs9332739), CFI (rs10033900), LIPC (rs10468017), TIMP3 (rs9621532) and CETP (rs3764261) were confirmed with genome-wide significant signals in this large study. Loci in the recently reported genes ABCA1 and COL8A1 were also detected with suggestive evidence of association with advanced AMD. The novel variants identified in this study suggest that angiogenesis (VEGFA) and extracellular collagen matrix (FRK/COL10A1) pathways contribute to the development of advanced AMD
Can Clinical and Surgical Parameters Be Combined to Predict How Long It Will Take a Tibia Fracture to Heal? A Prospective Multicentre Observational Study: The FRACTING Study
Background. Healing of tibia fractures occurs over a wide time range of months, with a number of risk factors contributing to prolonged healing. In this prospective, multicentre, observational study, we investigated the capability of FRACTING (tibia FRACTure prediction healING days) score, calculated soon after tibia fracture treatment, to predict healing time. Methods. The study included 363 patients. Information on patient health, fracture morphology, and surgical treatment adopted were combined to calculate the FRACTING score. Fractures were considered healed when the patient was able to fully weight-bear without pain. Results. 319 fractures (88%) healed within 12 months from treatment. Forty-four fractures healed after 12 months or underwent a second surgery. FRACTING score positively correlated with days to healing: r = 0.63 (p < 0.0001). Average score value was 7.3 \ub1 2.5; ROC analysis showed strong reliability of the score in separating patients healing before versus after 6 months: AUC = 0.823. Conclusions. This study shows that the FRACTING score can be employed both to predict months needed for fracture healing and to identify immediately after treatment patients at risk of prolonged healing. In patients with high score values, new pharmacological and nonpharmacological treatments to enhance osteogenesis could be tested selectively, which may finally result in reduced disability time and health cost savings
Production of He-4 and (4) in Pb-Pb collisions at root(NN)-N-S=2.76 TeV at the LHC
Results on the production of He-4 and (4) nuclei in Pb-Pb collisions at root(NN)-N-S = 2.76 TeV in the rapidity range vertical bar y vertical bar <1, using the ALICE detector, are presented in this paper. The rapidity densities corresponding to 0-10% central events are found to be dN/dy4(He) = (0.8 +/- 0.4 (stat) +/- 0.3 (syst)) x 10(-6) and dN/dy4 = (1.1 +/- 0.4 (stat) +/- 0.2 (syst)) x 10(-6), respectively. This is in agreement with the statistical thermal model expectation assuming the same chemical freeze-out temperature (T-chem = 156 MeV) as for light hadrons. The measured ratio of (4)/He-4 is 1.4 +/- 0.8 (stat) +/- 0.5 (syst). (C) 2018 Published by Elsevier B.V.Peer reviewe
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