Pathologic Epithelial and Anterior Corneal Nerve Morphology in Early-Stage Congenital Aniridic Keratopathy

Objective: To document the clinical and morphologic corneal findings in the early stages of congenital aniridic keratopathy in Swedish families. less thanbrgreater than less thanbrgreater thanDesign: Prospective, observational, comparative case series. less thanbrgreater than less thanbrgreater thanParticipants: A total of 16 eyes of 16 subjects with congenital aniridic keratopathy and a clear central cornea, and 6 eyes from 6 healthy controls (unaffected relatives). Nine of the 16 eyes with aniridia came from 5 families with a documented familial history of aniridia. less thanbrgreater than less thanbrgreater thanMethods: Detailed ophthalmic examinations included best spectacle-corrected visual acuity (BSCVA), tear film production, tear break-up time (BUT), corneal touch sensitivity, intraocular pressure measurement, ultrasound pachymetry, slit-lamp biomicroscopy, and laser scanning in vivo confocal microscopy (IVCM). less thanbrgreater than less thanbrgreater thanMain Outcome Measures: Confirmed stage of aniridic keratopathy, clinical parameters of cornea and tear film (visual acuity, sensitivity, corneal thickness, tear production, and BUT), and the morphologic status of corneal epithelium, sub-basal nerves, and limbal palisades of Vogt. less thanbrgreater than less thanbrgreater thanResults: In early-stage aniridic keratopathy, BSCVA and tear BUT were reduced relative to controls (P andlt; 0.001 for both), and corneal thickness was increased (P = 0.01). Inflammatory dendritic cells were present in the central epithelium in aniridia, with significantly increased density relative to controls (P = 0.001). Discrete focal opacities in the basal epithelial region were present in 5 of 11 aniridia cases with an otherwise clear cornea. Opacities were associated with dendritic cells and harbored structures presumed to be goblet cells. Sub-basal nerves were extremely dense in 3 aniridia cases, and a prominent whorl pattern of nerves and epithelial cells was observed in 1 case. Normal limbal palisade morphology was absent in aniridia but present in controls. less thanbrgreater than less thanbrgreater thanConclusions: Early-stage aniridic keratopathy is characterized by the development of focal opacities in the basal epithelium, altered sub-basal nerves, infiltration of the central epithelium by dendritic cells, tear film instability, and increased corneal thickness and degradation of limbal palisade architecture. These findings may help to elucidate the pathogenesis of aniridic keratopathy. less thanbrgreater than less thanbrgreater thanFinancial Disclosure(s): The author(s) have no proprietary or commercial interest in any materials discussed in this article.Funding Agencies|European Union||Crown Princess Margaretas Foundation for the Visually Impaired||Swedish Eye Fund||Carmen and Bertil Regners Foundation||David and Beth Dahlins Foundation||King Gustav V and Queen Victorias Freemasons Foundation||County Council of Ostergotland||Association of the Blind in Ostergotland||</p

Supplying a Brushless DC Motor by z-source PV power inverter with FLC-IC MPPT by DTC drive

This paper describes the optimal operation performance of a Brushless DC Motor (BLDC) fed by a z-source inverter accompanying with photovoltaic (PV) system, driving a water pumping system. The proposed system employs a Z-Source Inverter (ZSI) to extract the Maximum Power from a Photovoltaic array to supply the BLDC motor simultaneously. Utilizing the ZSI provides some advantages such as high efficiency and low cost. In order to achieve an accurate Maximum Power Point Tracking (MPPT) of the PV array, fuzzy logic controller(FLC) is applied to attain an appropriate variable step size in incremental conductance method. Direct torque control (DTC) has some benefits such as faster torque response and reduced torque ripple for driving the BLDC motor. Because of ignoring stator flux linkage of DTC in constant torque region, driving of BLDC motor is not complicated. The effectiveness of proposed system is evaluated by simulation results

Review of permanent-magnet brushless DC motor basic drives based on analysis and simulation study

Brushless DC (BLDC) motors and their drives have been increasingly considered in a broad range of applications due to their significant features. The implementation of these motors is possible thanks to firstly, the progress of permanent-magnet (PM) technologies which provide high efficiency, power density, and torque for these motors. Secondly, the structure and special features of these motors have prepared a basis for simpler control and smaller size compared to those with the same power. In this paper, the basic drives of BLDC motors have been reviewed in order to provide a useful reference for primary research in conventional methods of these types of motors. To present a proper insight to various drive techniques in these motors a systematic classification to control strategies with principles of these techniques has been made. In addition, computer simulations have been utilized in order to achieve a more accurate evaluation, provide the possibility of comparative analysis between various strategies, and place emphasis on the constraints and features of each method. Apart from the comparison of different methods of each strategy, a general comparison among the different methods of various strategies has been made based on the torque ripple, analysis of frequency, and losses of the BLDC motor drive as well as various applications of the different controlling methods. Moreover, considering the importance of electric vehicles (EVs) in industry, selection of the best controlling method for this type of applications together with energy regeneration has been discussed

Hybrid instrumentation in lumbar spinal fusion : a biomechanical evaluation of three different Instrumentation techniques

Study Design Ex vivo human cadaveric study. Objective The development or progression of adjacent segment disease (ASD) after spine stabilization and fusion is a major problem in spine surgery. Apart from optimal balancing of the sagittal profile, dynamic instrumentation is often suggested to prevent or impede ASD. Hybrid instrumentation is used to gain stabilization while allowing motion to avoid hypermobility in the adjacent segment. In this biomechanical study, the effects of two different hybrid instrumentations on human cadaver spines were evaluated and compared with a rigid instrumentation. Methods Eighteen human cadaver spines (T11-L5) were subdivided into three groups: rigid, dynamic, and hook comprising six spines each. Clinical parameters and initial mechanical characteristics were consistent among groups. All specimens received rigid fixation from L3-L5 followed by application of a free bending load of extension and flexion. The range of motion (ROM) for every segment was evaluated. For the rigid group, further rigid fixation from L1-L5 was applied. A dynamic Elaspine system (Spinelab AG, Winterthur, Switzerland) was applied from L1 to L3 for the dynamic group, and the hook group was instrumented with additional laminar hooks at L1-L3. ROM was then evaluated again. Results There was no significant difference in ROM among the three instrumentation techniques. Conclusion Based on this data, the intended advantage of a hybrid or dynamic instrumentation might not be achieve