The multi-disciplinary design study: A life cycle cost algorithm

The approach and results of a Life Cycle Cost (LCC) analysis of the Space Station Solar Dynamic Power Subsystem (SDPS) including gimbal pointing and power output performance are documented. The Multi-Discipline Design Tool (MDDT) computer program developed during the 1986 study has been modified to include the design, performance, and cost algorithms for the SDPS as described. As with the Space Station structural and control subsystems, the LCC of the SDPS can be computed within the MDDT program as a function of the engineering design variables. Two simple examples of MDDT's capability to evaluate cost sensitivity and design based on LCC are included. MDDT was designed to accept NASA's IMAT computer program data as input so that IMAT's detailed structural and controls design capability can be assessed with expected system LCC as computed by MDDT. No changes to IMAT were required. Detailed knowledge of IMAT is not required to perform the LCC analyses as the interface with IMAT is noninteractive

Disease of the Year : Differential Diagnosis of Uveitic Macular Edema

Uveitic cystoid macular edema (UME) is an important cause of visual morbidity among patients with both infectious and non-infectious uveitis. UME may be associated in more than 30% cases of active uveitis. However, even patients with minimal features of intraocular inflammation may develop recurrent or chronic UME. Therefore, the evaluation and management of UME in patients with uveitis may be challenging. A number of vitreoretinal pathologies may result in UME and accumulation of fluid in the intra- or subretinal space. These need to be carefully distinguished from each other so that appropriate management can be initiated. All types of uveitis, including anterior uveitis (where the primary site of inflammation is not in the posterior segment) can present with UME. Other conditions such as diabetes, and surgery, can present with macular edema. This index review highlights various differential diagnoses of UME and provides illustrative case examples with multimodal imaging evaluation

Efficient computation of bifurcation diagrams with a deflated approach to reduced basis spectral element method

The majority of the most common physical phenomena can be described using partial differential equations (PDEs). However, they are very often characterized by strong nonlinearities. Such features lead to the coexistence of multiple solutions studied by the bifurcation theory. Unfortunately, in practical scenarios, one has to exploit numerical methods to compute the solutions of systems of PDEs, even if the classical techniques are usually able to compute only a single solution for any value of a parameter when more branches exist. In this work, we implemented an elaborated deflated continuation method that relies on the spectral element method (SEM) and on the reduced basis (RB) one to efficiently compute bifurcation diagrams with more parameters and more bifurcation points. The deflated continuation method can be obtained combining the classical continuation method and the deflation one: the former is used to entirely track each known branch of the diagram, while the latter is exploited to discover the new ones. Finally, when more than one parameter is considered, the efficiency of the computation is ensured by the fact that the diagrams can be computed during the online phase while, during the offline one, one only has to compute one-dimensional diagrams. In this work, after a more detailed description of the method, we will show the results that can be obtained using it to compute a bifurcation diagram associated with a problem governed by the Navier-Stokes equations

Multimodal imaging in hereditary retinal diseases

Introduction. In this retrospective study we evaluated the multimodal visualization of retinal genetic diseases to better understand their natural course. Material and Methods. We reviewed the charts of 70 consecutive patients with different genetic retinal pathologies who had previously undergone multimodal imaging analyses. Genomic DNA was extracted from peripheral blood and genotyped at the known locus for the different diseases. Results. The medical records of 3 families of a 4-generation pedigree affected by North Carolina macular dystrophy were reviewed. A total of 8 patients with Stargardt disease were evaluated for their two main defining clinical characteristics, yellow subretinal flecks and central atrophy. Nine male patients with a previous diagnosis of choroideremia and eleven female carriers were evaluated. Fourteen patients with Best vitelliform macular dystrophy and 6 family members with autosomal recessive bestrophinopathy were included. Seven patients with enhanced s-cone syndrome were ascertained. Lastly, we included 3 unrelated patients with fundus albipunctatus. Conclusions. In hereditary retinal diseases, clinical examination is often not sufficient for evaluating the patient's condition. Retinal imaging then becomes important in making the diagnosis, in monitoring the progression of disease, and as a surrogate outcome measure of the efficacy of an intervention

Corneal confocal microscopy in dry eye treated with corticosteroids

Purpose To evaluate, by in vivo laser scanning confocal microscopy (LSCM), the corneal findings in moderate-to-severe dry eye patients before and after treatment with topical corticosteroid and to associate the confocal findings to the clinical response. Methods Fifty eyes of 50 patients with moderate-to-severe dry eye were included in this open-label, masked study. Exclusion criteria were any systemic or ocular condition (other than dry eye) and any systemic or topical treatment (except artificial tears), ongoing or performed in the previous 3 months, with known effect on the ocular surface. All patients were treated with loteprednol etabonate ophthalmic suspension 0.5% qid for 4 weeks. Baseline and follow-up (day 30 \ub1 2) visits included Ocular Surface Disease Index (OSDI) questionnaire, full eye examination, and central cornea LSCM. We compared data obtained before and after treatment and looked for associations between baseline data and steroid-induced changes. Based on the previously validated OSDI Minimal Clinically Important Difference, we reanalyzed the baseline findings comparing those patients clinically improved after steroids to patients not clinically improved after steroids. Results Ocular Surface Disease Index score and LSCM dendritic cell density (DCD) significantly decreased after treatment. Baseline DCD correlated with both OSDI and DCD steroid-related changes (r = -0.44, p 2, p < 0.01; independent samples t test). Conclusions Laser scanning confocal microscopy examination of DCD allows detection of treatment-related inflammation changes and shows previously unknown associations between confocal finding and symptoms improvement after treatment. These promising preliminary data suggest the need for future studies testing the predictive value of DCD for a clinical response to topical corticosteroids

Neovascular glaucoma induced by peripheral retinal ischemia in neurofibromatosis type 1: Management and imaging features

Purpose: To report the case of a young patient affected by neurofibromatosis 1 (NF-1) with peripheral retinal ischemia-induced neovascular glaucoma and the peculiar spectral-domain optical coherence tomography (SD-OCT) features. Material and Methods: A 13-year-old boy affected by NF-1, as diagnosed according to established criteria, was referred with a diagnosis of hypertensive uveitis in his left eye. He underwent a complete ophthalmic examination and comprehensive blood work with viral and immunological tests. The case was documented with fluorescein angiography (FA) and SD-OCT. When the intraocular pressure (IOP) of the left eye decreased and the cornea cleared, FA revealed retinal ischemia and leakage from pathologic retinal vessels. SD-OCT revealed foveal hypoplasia secondary to the complete absence of the retinal nerve fiber layer. Results: Peripheral retinal ischemia-induced neovascular glaucoma was diagnosed. The patient underwent Ahmed valve implantation to control his IOP, and subsequent retinal photocoagulation by argon laser and intravitreal bevacizumab injection were performed to control neovascularization. Discussion: Retinal ischemia in NF-1 might lead to neovascular glaucoma: lowering of the IOP with surgical implantation of an Ahmed valve, regression of neovascularization by argon laser panretinal photocoagulation and intravitreal injection of bevacizumab can be a helpful way to control such a complication

Dry eye in vernal keratoconjunctivitis

The purpose of this comparative cross-sectional study was to investigate the use of standardized clinical tests for dry eye in pediatric patients with active and quiet vernal keratoconjunctivitis (VKC) and to compare them with healthy children. We recruited 35 active VKC, 35 inactive VKC, and 70 age-matched control healthy subjects. Each child underwent a complete eye examination, including visual analog scale symptoms assessment, biomicroscopy, fluorescein break-up time (BUT), corneal fluorescein and conjunctival lissamine green staining, corneal esthesiometry, Schirmer test with anesthetic, and meibomian glands inspection and expression. Active VKC patients showed significantly increased symptoms and signs of ocular surface disease, compared with the other 2 groups. Inactive VKC patients, compared with control subjects, showed increased photophobia (P<0.05; Mann-Whitney U test), conjunctival lissamine green staining and Schirmer test values, and reduced BUT and corneal sensitivity [P<0.05 by analysis of variance (ANOVA) least significant difference posthoc test for BUT and Schirmer; P<0.001 by Mann-Whitney U test for lissamine green staining and corneal sensitivity]. Our results confirm the association between VKC and short-BUT dry eye. This syndrome seems to affect the ocular surface in quiescent phases too, determining abnormalities in tear film stability, epithelial cells integrity, and corneal nerves function. The very long-term consequences of this perennial mechanism of ocular surface damage have not been fully understood yet

Automated quantification of uveitic keratic precipitates by use of anterior segment optical coherence tomography

BACKGROUND: Evaluation of ocular inflammation via common imaging modalities like optical coherence tomography (OCT) has emphasised cell visualisation, but automated detection of uveitic keratic precipitates (KPs) remains unexplored. METHODS: Anterior segment (AS)-OCT dense volumes of the corneas of patients with uveitic KPs were collected at three timepoints: with active (T0), clinically improving (T1), and resolved (T2) inflammation. At each visit, visual acuity and clinical grading of the anterior chamber cells were assessed. A bespoke algorithm was used to create an en face rendering of the KPs and to calculate their volume and a ratio of the volume of precipitates over the analysed area. The variation of AS-OCT-derived measurements over time was assessed, and compared with clinical grading. RESULTS: Twenty eyes from 20 patients (13 females, mean age 39 years) were studied. At T0, the mean volume of the corneal KPs was 0.1727 mm3 , and it significantly reduced to 0.1111 mm3 (p = 0.03) only at T2. The ratio between the volume of the KPs and the corneal area decreased from T0 (0.007) to T1 (0.006; p = 0.2) and T2 (0.004; p = 0.009). There was a statistically significant correlation between the AC cell count and the AS-OCT volume measurements of the KPs at the three time points. CONCLUSIONS: AS-OCT can image uveitic KPs and through a bespoke algorithm we were able to create an en face rendering allowing us to extrapolate their volume. We found that objective quantification of KPs correlated with inflammatory cell counts in the anterior chamber

Lembo miofasciale di vasto laterale nella ricostruzione della lingua

Nell'ultimo decennio il lembo antero-laterale di coscia (ALT) è diventato il lembo libero più utilizzato nella ricostruzione della lingua, dal momento che esso è caratterizzato da bassa morbidità a livello del sito donatore e da migliori risultati estetici. Tuttavia, l'ALT fascio-cutaneo può essere insufficiente nella ricostruzione nei difetti maggiori (es. glossectomia totale) mentre la sua variante muscolo-cutanea (che include il muscolo vasto laterale)' può essere troppo voluminosa. Scopo dello studio è quello di descrivere la nostra esperienza preliminare nella ricostruzione della lingua utilizzando il lembo libero mio-fasciale di vasto laterale che potrebbe a nostro parere offrire notevoli vantaggi nella ricostruzione testa-collo come: possibilità di confezionare un lembo voluminoso quando necessario, ottimi risultati funzionali, obliterazione di spazi morti con prevenzione dello sviluppo di fistola e infezione con minima morbidità a livello del sito donatore