Electromagnetic informed data model considerations for near-field DOA and range estimates.

Localizing sources in the near-field is one of the emerging challenges for array signal processing, which has received a great deal of attention in recent years. The development of accurate localization algorithms requires the definition of a reliable model of the received signal that takes into account all wavefront characteristics, such as angle, range, and polarization, as well as electromagnetic effects, such as mutual coupling between antennas and the amplitude and phase behaviour of electromagnetic wavefronts. A system model that considers the electromagnetic-informed wave behaviour effects, independent of the type of receiver antennas, array structure, degree of correlation of sources signals and other electromagnetic effects, is considered an " exact model " in the literature. However, due to the mathematical complexity of this modeling approach, simplifications using several approximations are conventionally used. For instance, the phase of the exact model is approximated using the Fresnel approximation, while the magnitude of the exact model is simplified by assuming equal distances between the source and all elements in the array. In this work, we evaluate the accuracy of a localization algorithm, the multiple signal classification (MUSIC), using the exact and approximated models in the near-field region. Through a series of simulations, we demonstrate that the localization algorithm designed based on the electromagnetic-informed exact model outperforms the one designed using the approximated model. We also show that considering electromagnetic factors in the system model through the exact model results in a 13% improvement in the direction of arrival (DOA) root mean square error (RMSE) and a 57.7% improvement in range RMSE at signal-to-noise ratio (SNR) of 15 dB.

Upcoming Methods and Specifications of Continuous Intraocular Pressure Monitoring Systems for Glaucoma.

Glaucoma is the leading cause of irreversible blindness and vision loss in the world. Although intraocular pressure (IOP) is no longer considered the only risk factor for glaucoma, it is still the most important one. In most cases, high IOP is secondary to trabecular meshwork dysfunction. High IOP leads to compaction of the lamina cribrosa and subsequent damage to retinal ganglion cell axons. Damage to the optic nerve head is evident on funduscopy as posterior bowing of the lamina cribrosa and increased cupping. Currently, the only documented method to slow or halt the progression of this disease is to decrease the IOP; hence, accurate IOP measurement is crucial not only for diagnosis, but also for the management. Due to the dynamic nature and fluctuation of the IOP, a single clinical measurement is not a reliable indicator of diurnal IOP; it requires 24-hour monitoring methods. Technological advances in microelectromechanical systems and microfluidics provide a promising solution for the effective measurement of IOP. This paper provides a broad overview of the upcoming technologies to be used for continuous IOP monitoring.

Toward the Art of Robotic-assisted Vitreoretinal Surgery.

New technological progress in robotics has brought many beneficial clinical applications. Currently, computer integrated robotic surgery has gained clinical acceptance for several surgical procedures. Robotically assisted eye surgery is envisaged as a promising solution to overcome the shortcomings inherent to conventional surgical procedures as in vitreoretinal surgeries. Robotics by its high precision and fine mechanical control can improve dexterity, cancel tremor, and allow highly precise remote surgical capability, delicate vitreoretinal manipulation capabilities. Combined with magnified three-dimensional imaging of the surgical site, it can enhance surgical precision. Tele-manipulation can provide the ability for tele-surgery or haptic feedback of forces generated by the manipulation of intraocular tissues. It presents new solutions for some sight-threatening conditions such as retinal vein cannulation where, due to physiological limitations of the surgeon's hand, the procedure cannot be adequately performed. In this paper, we provide an overview of the research and advances in robotically assisted vitreoretinal eye surgery. Additionally the barriers to the integration of this method in the field of ocular surgery are summarized. Finally, we discuss the possible applications of the method in the area of vitreoretinal surgery.

Primary Hydatid Cyst of Umbilicus, Mimicking an Umbilical Hernia.

Hydatid cyst caused by Echinococcus granulosus demonstrates an endemic infection in several countries such as Middle Eastern countries. Liver is the most frequently involved organ, followed by the lung. The case we present is solitary primary localization of cyst in abdominal wall which is extremely rare. A 57-year-old woman presented with an abdominal wall lesion in umbilical area that had been evolving for about 2 years with recent complaint of pain and discomfort. We detected a midline abdominal mass 12⁎13 centimeters in diameter which was bulged out in umbilicus. Preoperative clinical diagnosis of incarcerated umbilical hernia was made due to its physical examination while surgical exploration disproved the primary diagnosis and we found cystic mass adherent to superficial fascia without any communication to peritoneal space. The cyst was excised completely without any injury or perforation of containing capsule. The diagnosis of hydatid cyst was confirmed by histopathological examination of specimen. The retrograde evaluation showed no involvement of other organs. The patient was followed for two years and no recurrence of hydatid disease has been observed. Hydatid cyst should be considered as a differential diagnosis of abdominal wall and umbilical lesions especially in endemic regions.