Nanoporous Layers and the Peculiarities of Their Local Formation on a Silicon Wafer

This review presents the results of the local formation of nanostructured porous silicon (NPSi) on the surface of silicon wafers by anodic etching using a durite intermediate ring. The morphological and crystallographic features of NPSi structures formed on n- and p-type silicon with low and relatively high resistivity have also been investigated. The proposed scheme allows one to experiment with biological objects (for example, stem cells, neurons, and other objects) in a locally formed porous structure located in close proximity to the electronic periphery of sensor devices on a silicon wafer.

EXAMINATION OF STRESS-STRAIN STATE OF SPHERICAL TRANSFORMING MECHANISM ELEMENTS AT NON-ORTHOGONAL ARRANGEMENT EXTERNAL HINGES

Work is devoted to modeling of stress-strain state of spherical converting mechanism with non-orthogonal arrangement of hinges of outer ring relative to rocking axis of intermediate ring. Results of simulation of mechanism main elements loading in operating position are shown. Based on the obtained data, the most hazardous areas were identified and design recommendations were given

POS1393 QUANTITATIVE AUTOFLUORESCENCE FINDINGS IN PATIENTS UNDERGOING HYDROXYCHLOROQUINE TREATMENT

Background:Hydroxychloroquine (HCQ) is a relatively safe and effective drug widely used as primary or adjunctive treatment for several rheumatological and dermatological disorders1. HCQ modulates immune response through several mechanisms and has a tropism for pigmented ocular tissues, particularly retinal pigment epithelium (RPE)2. Its accumulation within RPE cells can lead to sight threatening retinal toxicity, with bull’s eye maculopathy (BEM) representing its advanced phenotype. 3 Quantitative Auto-Fluorescence (qAF) is an imaging modality that allows the measurement of retinal auto-fluorescence following short-wavelength light (488nm) excitation of retinal fluorophores (lipofuscin). 4 Two recent studies have focused on qAF values in patients treated with HCQ 5,6. In both cases qAF was increased in eyes with BEM. Furthermore, Reichel et al.6 were able to detect increased values of qAF in patients without BEM as early as 6 months after the start of HCQ treatment using an experimental imaging analysis procedure.Objectives:To measure quantitative autofluorescence (qAF) in patients under treatment with hydroxychloroquine (HCQ) with no apparent signs of retinal toxicity and to compare it with that of untreated subjects.Methods:Consecutive patients at risk for the development of HCQ retinal toxicity (duration of treatment >5 years or daily HCQ dose >5 mg/kg of actual body weight (ABW) and/or renal insufficiency)7 but no alterations on Spectral Domain - Optical Coherence Tomography, Short-Wavelength Autofluorescence and 10-2 Visual Field examination were recruited. Healthy subject matched by age and sex were also enrolled in the study. All subjects underwent qAF measurements in one eye. Images were analyzed using the conventional qAF grid by Delori calculating the qAF of 8 sectors of the intermediate ring and the mean of those values (qAF8).Results:Thirty-nine patients treated with HCQ (38 females, mean age 52,1 ± 8,6 years) and 39 untreated subjects (38 females, mean age 51,2 ± 8,6 years). In both HCQ patients and untreated subjects, qAF8 was positively correlated with age (p=0.004) (Figure 1). Although HCQ patients showed a higher mean qAF8 compared to untreated subjects (294,7 ±65,3 vs 268,9 ± 57,5), the difference was not significant (p=0.068). HCQ patients showed significantly higher mean qAF values in the inferior-temporal, inferior and inferior-nasal sectors of the intermediate ring of qAF grid compared to untreated subjects (all p<0.05).Figure 1.Visual representation of a model predicting the standardized qAF values as influenced by age and HCQ daily dose/ABW, calculated for a treatment duration of 15 years.Conclusion:These results suggest a possible preclinical increase of qAF values in inferior parafoveal sectors probably induced by HCQ exposure. Further studies are required to improve our understanding of preclinical stages of HCQ retinopathy and the possible role of qAF in the HCQ toxicity screening.References:[1]Haładyj, E., Sikora, M., Felis-Giemza, A. & Olesińska, M. Antimalarials - are they effective and safe in rheumatic diseases? Reumatologia56, 164–173 (2018).[2]Rosenthal, A. R., Kolb, H., Bergsma, D., Huxsoll, D. & Hopkins, J. L. Chloroquine retinopathy in the rhesus monkey. Invest. Ophthalmol. Vis. Sci.17, 1158–1175 (1978).[3]Modi, Y. S. & Singh, R. P. Bull’s-Eye Maculopathy Associated with Hydroxychloroquine. N. Engl. J. Med.380, 1656 (2019).[4]Sparrow, J. R., Duncker, T., Schuerch, K., Paavo, M. & de Carvalho, J. R. L. J. Lessons learned from quantitative fundus autofluorescence. Prog. Retin. Eye Res.74, 100774 (2020).[5]Greenstein, V. C. et al. Quantitative Fundus Autofluorescence in HCQ Retinopathy. Invest. Ophthalmol. Vis. Sci.61, 41 (2020).[6]Reichel, C. et al. Quantitative Fundus Autofluorescence in Systemic Chloroquine/Hydroxychloroquine Therapy. Transl. Vis. Sci. Technol.9, 42 (2020).[7]Yusuf, I. H., Sharma, S., Luqmani, R. & Downes, S. M. Hydroxychloroquine retinopathy. Eye (Lond).31, 828–845 (2017).Disclosure of Interests:Salvatore Parrulli: None declared, Mariano Cozzi Grant/research support from: Bayer, Nidek, Zeiss, Matteo Airaldi: None declared, Francesco Romano: None declared, Francesco Viola: None declared, Piercarlo Sarzi-Puttini: None declared, Giovanni Staurenghi Grant/research support from: Heidelberg Engineering (C), QuantelMedical (C), Centervue (C), Carl Zeiss Meditec (C), Alcon (C), Allergan (C), Bayer (C), Boheringer (C), Genentech (C), GSK (C),Novartis (C), and Roche (C), Optos (F), Optovue (F) and Centervue (F), Alessandro Invernizzi Grant/research support from: Novartis (C), Bayer (C)

Ring Extensions with Finitely Many Non-Artinian Intermediate Rings

The commutative ring extensions with exactly two non-Artinian intermediate rings are characterized. An initial step involves the description of the commutative ring extensions with only one non-Artinian intermediate ring.

Closure formula for ideals in intermediate rings

<p>In this paper, we prove that the closure formula for ideals in C(X) under m topology holds in intermediate ring also, i.e. for any ideal I in an intermediate ring with m topology, its closure is the intersection of all the maximal ideals containing I.</p>

On almost valuation ring pairs

If [Formula: see text] are (commutative) rings, [Formula: see text] denotes the set of intermediate rings and [Formula: see text] is called an almost valuation (AV)-ring pair if each element of [Formula: see text] is an AV-ring. Many results on AV-domains and their pairs are generalized to the ring-theoretic setting. Let [Formula: see text] be rings, with [Formula: see text] denoting the integral closure of [Formula: see text] in [Formula: see text]. Then [Formula: see text] is an AV-ring pair if and only if both [Formula: see text] and [Formula: see text] are AV-ring pairs. Characterizations are given for the AV-ring pairs arising from integrally closed (respectively, integral; respectively, minimal) ring extensions [Formula: see text]. If [Formula: see text] is an AV-ring pair, then [Formula: see text] is a P-extension. The AV-ring pairs [Formula: see text] arising from root extensions are studied extensively. Transfer results for the “AV-ring” property are obtained for pullbacks of [Formula: see text] type, with applications to pseudo-valuation domains, integral minimal ring extensions, and integrally closed maximal non-AV subrings. Several sufficient conditions are given for [Formula: see text] being an AV-ring pair to entail that [Formula: see text] is an overring of [Formula: see text], but there exist domain-theoretic counter-examples to such a conclusion in general. If [Formula: see text] is an AV-ring pair and [Formula: see text] satisfies FCP, then each intermediate ring either contains or is contained in [Formula: see text]. While all AV-rings are quasi-local going-down rings, examples in positive characteristic show that an AV-domain need not be a divided domain or a universally going-down domain.

Disproportion of lamellar capillary non-perfusion in proliferative diabetic retinopathy on optical coherence tomography angiography

PurposeTo characterise the non-perfused areas (NPAs) in the superficial and deep capillary layers (sNPAs and dNPAs, respectively) in the posterior pole in proliferative diabetic retinopathy (PDR) on wide-field optical coherence tomography angiography (OCTA) images.MethodsWe retrospectively reviewed 104 eyes of 70 patients with PDR from whom wide-field swept source OCTA images were acquired. sNPAs and dNPAs were manually measured in each quadrant of the inner (1–3 mm diameter), intermediate (3–6 mm), and outer (6–10 mm) rings centred on the fovea. Two qualitative findings, that is, segmented NPAs and periarteriolar NPAs, were also compared.ResultsThe dNPAs were greater than the sNPAs (p<0.001) in each subfield. The outer ring had higher rates of deep NPAs than did the intermediate ring in the superior, inferior and temporal quadrants (p=0.010, p=0.004 and p<0.001, respectively), whereas no differences were detected in the nasal quadrant (p=1.000). Similarly, sNPA rates were higher in the outer ring than in the intermediate ring in the inferior and temporal subfields (p=0.003 and p<0.001, respectively). In 45 eyes with extensive NPAs, there were modest correlations between the dNPAs in the nasal and temporal quadrants in the intermediate (ρ=0.341, p=0.026) and outer (ρ=0324, p=0.032) rings, whereas sNPAs exhibited no associations. Segmented NPAs were delineated more frequently in the superficial layer than in the deep layer (p<0.001). Periarteriolar NPAs were more frequent in the deep layer (p<0.001).ConclusionsThree-dimensional assessment of wide-field OCTA promotes a better understanding of the enigmatic disproportion of lamellar NPAs in the posterior pole in PDR.