446 research outputs found

    Towards the development of cascaded surface plasmon resonance POF sensors exploiting gold films and synthetic recognition elements for detection of contaminants in transformer oil

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    The possibility of developing a multichannel optical chemical sensor, based on molecularly imprinted polymers (MIPs) and surface plasmon resonance (SPR) in a D-shaped multimode plastic optical fiber (POF), is presented by two cascaded SPR-POF-MIP sensors with different thicknesses of the gold layer. The low cost, the high selectivity and sensitivity of the SPR-POF-MIP platforms and the simple and modular scheme of the optical interrogation layout make this system a potentially suitable on-line multi-diagnostic tool. As a proof of principle, the possibility of simultaneous determination of two important analytes, dibenzyl disulfide (DBDS) and furfural (2-FAL), in power transformer oil was investigated. Their presence gives useful indication of underway corrosive or ageing processes in power transformers, respectively. Preliminarily, the dependence of the performance of the D-shaped optical platform on the gold film thickness has been studied, comparing two platforms with 30 nm and 60 nm thick gold layers. It has been found that the resonance wavelengths are different on platforms with gold layer of different thickness, furthermore when MIPs are present on the gold as receptors, the performances of the platforms are similar in the two considered sensors. Keywords: Cascaded multianalyte detection, Surface plasmon resonance, Dibenzyl disulfide, Furfural (furan-2-carbaldehyde), Molecularly imprinted polymers, Plastic optical fiber

    Novel Optical Chemical Sensor Based on Molecularly Imprinted Polymer Inside a Trench Micro-machined in Double Plastic Optical Fiber☆

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    Abstract For the detection of chemical agents in different environments, the combination of plastic optical fibers (POFs) and molecularly imprinted polymer (MIP) layers has been tested as a way to obtain a low cost, highly selective and sensitive surface plasmon resonance (SPR) chemical sensor. A novel type of optical chemical sensor based on POF-MIP has been designed and fabricated, and in this work it has been applied for the selective detection of dibenzyl disulfide (DBDS) in transformer oil. This analyte is important in the control of transformer oil, since it is responsible for the corrosive properties of the oil. The new optical sensor platform is based on two plastic optical fibers coupled through a polymer molecularly imprinted for DBDS. The new sensor has been found to be useful for the determination of DBDS in transformer oil

    Anterior Segment-Optical Coherence Tomography features in Blau syndrome.

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    Blau syndrome (BS) is a rare granulomatous auto-inflammatory disease, characterized by the classic clinical triad of joints, skin and ocular involvements. Ocular manifestation usually consists in a bilateral insidious chronic anterior uveitis with a potential evolution to panuveitis. We describe the case of two siblings, an 8-years old female and a 5-years old male, with a diagnosis of BS, evaluated by Anterior Segment-Optical Coherence Tomography (AS-OCT). In the female patient, slit-lamp examination revealed bilateral anterior granulomatous uveitis and inflammatory sequelae. AS-OCT revealed high intensity reflective layers in the anterior cornea, hyperreflective dots both in the aqueous humor and in the posterior corneal surface. In the male, no signs of inflammation were detected both on slit-lamp examination and AS-OCT scans. AS-OCT is a valuable, non-invasive tool that could improve the diagnosis of ocular involvement, better characterize and follow-up corneal alterations and anterior segment features in pediatric patients with BS

    Novel USH1G homozygous variant underlying USH2-like phenotype of Usher syndrome

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    PURPOSE: Usher syndrome (USH) is an autosomal recessive disorder characterized by congenital sensorineural hearing impairment and retinitis pigmentosa. Classification distinguishes three clinical types of which type I (USH1) is the most severe, with vestibular dysfunction as an added feature. To date, 15 genes and 3 loci have been identified with the USH1G gene being an uncommon cause of USH. We describe an atypical USH1G-related phenotype caused by a novel homozygous missense variation in a patient with profound hearing impairment and relatively mild retinitis pigmentosa, but no vestibular dysfunction. METHODS: A 26-year-old female patient with profound congenital sensorineural hearing loss, nyctalopia and retinitis pigmentosa was studied. Audiometric, vestibular and ophthalmologic examination was performed. A panel of 13 genes was tested by next-generation sequencing (NGS). RESULTS: While the hearing loss was confirmed to be profound, the vestibular function resulted normal. Although typical retinitis pigmentosa was present, the age at onset was unusually late for USH1 syndrome. A novel homozygous missense variation (c.1187T>A, p.Leu396Gln) in the USH1G gene has been identified as causing the disease in our patient. CONCLUSIONS: Genetic and phenotypic heterogeneity are very common in both isolated and syndromic retinal dystrophies and sensorineural hearing loss. Our findings widen the spectrum of USH allelic disorders and strength the concept that variants in genes that are classically known as underlying one specific clinical USH subtype might result in unexpected phenotypes

    Prostate health index and multiparametric mri: Partners in crime fighting overdiagnosis and overtreatment in prostate cancer

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    Widespread use of PSA as the standard tool for prostate cancer (PCa) diagnosis led to a high rate of overdiagnosis and overtreatment. In this study, we evaluated the performance of the prostate health index (PHI) and multiparametric magnetic resonance imaging (mpMRI) for the prediction of positive biopsy and of high‐grade PCa at radical prostatectomy (RP). To this end, we prospectively enrolled 196 biopsy‐naïve patients who underwent mpMRI. A subgroup of 116 subjects with biopsy‐proven PCa underwent surgery. We found that PHI significantly outperformed both PI‐RADS score (difference in AUC: 0.14; p < 0.001) and PHI density (difference in AUC: 0.08; p = 0.002) in the ability to predict positive biopsy with a cut‐off value of 42.7 as the best threshold. Conversely, comparing the performance in the identification of clinically significant prostate cancer (csPCa) at RP, we found that PHI ≥61.68 and PI‐RADS score ≥4 were able to identify csPCa (Gleason score ≥7 (3 + 4)) both alone and added to a base model including age, PSA, fPSA‐to-tPSA ratio and prostate volume. In conclusion, PHI had a better ability than PI‐RADS score to predict positive biopsy, whereas it had a comparable performance in the identification of pathological csPCa

    Primary vitrectomy for degenerative and tractional lamellar macular holes: A systematic review and meta-analysis

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    Purpose To assess the efficacy of vitrectomy in degenerative and tractional lamellar macular holes (LMHs) by meta-analysis of published studies. Methods PubMed, Medline and Embase databases were searched up to May 2020. Included cohorts were divided into three groups: degenerative LMH group, lamellar hole associated epiretinal proliferation (LHEP) group and tractional LMH group. LHEP is likely to be associated with degenerative LMHs, but less commonly could be associated with mixed LMHs. To reduce risk of possible misclassification bias, eyes with LHEP which could not have been precisely classified by the authors, were included into the LHEP group. The primary outcome was to investigate the visual change following primary vitrectomy in the degenerative LMH and LHEP group versus the tractional LMH group. A sensitivity analysis excluding the LHEP group was also performed on the primary outcome. Mean difference (MD) in best corrected visual acuity between baseline and post-treatment was calculated, along with 95% confidence interval (CI). Rate of incidence of post-operative full-thickness macular hole (FTMH) was assessed as secondary outcome. Results Thirteen studies were included. Pooled analyses including all groups showed a significant visual improvement following vitrectomy (pre-post MD = -0.17;95%CI = -0.22,-0.12; p&lt;0.001), with no difference in visual improvement between the degenerative LMH and LHEP group and the tractional LMH group. The sensitivity analysis excluding LHEP group confirmed no difference in visual change between the degenerative LMH group (pre-post MD = -0.18;95%CI = -0.24,-0.12;p&lt;0.001) and the tractional LMH group (MD = -0.16;95%CI = -0.26,-0.07;p&lt;0.001). The incidence rate of post-operative FTMH was higher in the degenerative LMH and LHEP group than in the tractional LMH group (p = 0.002). Conclusion Primary vitrectomy for LMH ensured a favorable visual outcome, with no difference in visual gain between degenerative and tractional LMHs. However, a higher incidence of post-operative FTMHs was found in eyes with the degenerative LMH subtype

    Retinal Vascular Assessment in Psoriasis: A Multicenter Study

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    Purpose: To investigate the vascular status of the macula in psoriasis patients without history of ocular inflammation by Optical Coherence Tomography Angiography (OCTA). Methods: This prospective cross-sectional multicenter study included 55 psoriasis patients and 55 control healthy subjects. A complete eye examination and 6 mm × 6 mm OCTA imaging were performed. Retinal vascular status was evaluated by analyzing vascular density (VD) of superficial vascular plexus (superficial wVD) and deep vascular plexuses (deep wVD) in a 6 mm × 6 mm area and in foveal (superficial fVD and deep fVD) and parafoveal sectors (superficial pVD and deep pVD). In addition, foveal thickness (FT) and foveal avascular zone (FAZ) and clinical variables, including best corrected visual acuity (BCVA), intraocular pressure and refractive condition, were collected. Results: BCVA, intraocular pressure and refractive condition were comparable between cases and controls. OCTA imaging showed that superficial wVD and superficial pVD were lower in the psoriasis group in comparison with controls (p = 0.009 and p = 0.01, respectively). Similarly, deep wVD and pVD were lower in the psoriasis group in comparison with control subjects (p = 0.03 and p = 0.01, respectively). In a sub-analysis of 47 patients affected by psoriasis without psoriatic arthritis, lower values of wVD and pVD in both superficial and deep capillary plexuses were registered. Conclusion: OCTA is a useful tool which provides data on vascular status of the retina in psoriasis with no ocular involvement. VD data may suggest that vascular changes may occur earlier than clinical onset of posterior inflammation
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