Repeatability of Foveal Measurements Using Spectralis Optical Coherence Tomography Segmentation Software

PURPOSE: To investigate repeatability and reproducibility of thickness of eight individual retinal layers at axial and lateral foveal locations, as well as foveal width, measured from Spectralis spectral domain optical coherence tomography (SD-OCT) scans using newly available retinal layer segmentation software. METHODS: High-resolution SD-OCT scans were acquired for 40 eyes of 40 young healthy volunteers. Two scans were obtained in a single visit for each participant. Using new Spectralis segmentation software, two investigators independently obtained thickness of each of eight individual retinal layers at 0°, 2° and 5° eccentricities nasal and temporal to foveal centre, as well as foveal width measurements. Bland-Altman Coefficient of Repeatability (CoR) was calculated for inter-investigator and inter-scan agreement of all retinal measurements. Spearman's ρ indicated correlation of manually located central retinal thickness (RT0) with automated minimum foveal thickness (MFT) measurements. In addition, we investigated nasal-temporal symmetry of individual retinal layer thickness within the foveal pit. RESULTS: Inter-scan CoR values ranged from 3.1μm for axial retinal nerve fibre layer thickness to 15.0μm for the ganglion cell layer at 5° eccentricity. Mean foveal width was 2550μm ± 322μm with a CoR of 13μm for inter-investigator and 40μm for inter-scan agreement. Correlation of RT0 and MFT was very good (ρ = 0.97, P 0.05); however this symmetry could not be found at 5° eccentricity. CONCLUSIONS: We demonstrate excellent repeatability and reproducibility of each of eight individual retinal layer thickness measurements within the fovea as well as foveal width using Spectralis SD-OCT segmentation software in a young, healthy cohort. Thickness of all individual retinal layers were symmetrical at 2°, but not at 5° eccentricity away from the fovea

Strategic Response by providers to specialty hospitals, ambulatory surgery centers, and retail clinics.

Radical innovation and disruptive technologies are frequently heralded as a solution to delivering higher quality, lower cost health care. According to the literature on disruption, local hospitals and physicians (incumbent providers) may be unable to competitively respond to such creative destruction and alter their business models for a host of reasons, thus threatening their future survival. However, strategic management theory and research suggest that, under certain conditions, incumbent providers may be able to weather the discontinuities posed by the disrupters. This article analyzes 3 disruptive innovations in service delivery: single-specialty hospitals, ambulatory surgical centers, and retail clinics. We first discuss the features of these innovations to assess how disruptive they are. We then draw on the literature on strategic adaptation to suggest how incumbents develop competitive responses to these disruptive innovations that assure their continued survival. These arguments are then evaluated in a field study of several urban markets based on interviews with both incumbents and entrants. The interviews indicate that entrants have failed to disrupt incumbent providers primarily as a result of strategies pursued by the incumbents. The findings cast doubt on the prospects for these disruptive innovations to transform health care

Corporate Structure and Performance Feedback: Aspirations and Adaptation in M-Form Firms

In this study, we examine how business units of multidivisional (M-form) firms adapt their activities in response to poor performance at the corporate and business unit levels. By linking performance feedback theory with theories of attention and M-form organizations, we show that corporate structure influences the relationship between performance below aspirations and business unit adaptation. Because corporate structure vertically differentiates performance goals and problemistic search, solutions to performance problems vary across corporate and business unit levels, with divergent implications for business unit adaptation. We examine business unit adaptation empirically through new product introductions in the global mobile device industry, finding that poor performance at the business unit level leads to greater new product introductions. In contrast, corporate-level responses to performance problems have a negative cross-level effect on new product introductions. We also find that these negative effects are attenuated for strategically significant business units, which have more input into corporate responses. By linking structural and behavioral drivers of action, this paper contributes to the knowledge and understanding of adaptive behavior in multidivisional firms

SANS from micellar solutions of CTAB and sodium salicylate

SANS from 0.1M solution of CTAB without and with addition of varying concentrations of NaSal has been studied. The measured spectra show that on addition of NaSal two or more of CTAB micelles join together to form a bigger micelle. These micelles disintegrate to smaller ones on heating

A Rare but Important Clinical Presentation of Induced Methemoglobinemia

Phenazopyridine is considered one of the classic causes of drug-induced methemoglobinemia. It is often taught as such and seen in board review courses. Nevertheless, the epidemiology is unknown, presentation quite rare, and less than five cases have been reported in PubMed in over 35 years.1-4 We present a case with a different set of patient characteristics than seen in the few recent case reports, and an approach to treatment that validates further uniqueness, justifying reporting the case in the literature. In particular, the patient was a young otherwise-healthy adult, with the initial diagnosis and decision to treat based on clinical grounds versus laboratory values.