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This paper proposes a hexagonal photonic crystal fiber (H-PCF) structure with all circular air holes in order to simultaneously achieve ultrahigh birefringence and high nonlinearity. The H-PCF design consists of an asymmetric core region, where one air hole is a reduced diameter and the air hole in its opposite vertex is omitted. The light-guiding properties of the proposed H-PCF structure were studied using the full-vector finite element method (FEM) with a circular perfectly matched layer (PML). The simulation results showed that the proposed H-PCF exhibits an ultrahigh birefringence of 3.87 × 10−2, a negative dispersion coefficient of −753.2 ps/(nm km), and a nonlinear coefficient of 96.51 W−1 km−1 at an excitation wavelength of 1550 nm. The major advantage of our H-PCF design is that it provides these desirable modal properties without using any non-circular air holes in the core and cladding region, thus making the fiber fabrication process much easier. The ultrahigh birefringence, large negative dispersion, and high nonlinearity of our designed H-PCF make it a very suitable candidate for optical backpropagation applications, which is a scheme for the simultaneous dispersion and nonlinearity compensation of optical-fiber transmission links.

PurposeThe unfolded protein response (UPR) is triggered when the protein folding capacity of the endoplasmic reticulum (ER) is overwhelmed and misfolded proteins accumulate in the ER, a condition referred to as ER stress. IRE1α is an ER-resident protein that plays major roles in orchestrating the UPR. Several lines of evidence implicate the UPR and its transducers in neurodegenerative diseases, including retinitis pigmentosa (RP), a group of inherited diseases that cause progressive dysfunction and loss of rod and cone photoreceptors. This study evaluated the contribution of IRE1α to photoreceptor development, homeostasis, and degeneration.MethodsWe used a conditional gene targeting strategy to selectively inactivate Ire1α in mouse rod photoreceptors. We used a combination of optical coherence tomography (OCT) imaging, histology, and electroretinography (ERG) to assess longitudinally the effect of IRE1α deficiency in retinal development and function. Furthermore, we evaluated the IRE1α-deficient retina responses to tunicamycin-induced ER stress and in the context of RP caused by the rhodopsin mutation RhoP23H.ResultsOCT imaging, histology, and ERG analyses did not reveal abnormalities in IRE1α-deficient retinas up to 3 months old. However, by 6 months of age, the Ire1α mutant animals showed reduced outer nuclear layer thickness and deficits in retinal function. Furthermore, conditional inactivation of Ire1α in rod photoreceptors accelerated retinal degeneration caused by the RhoP23H mutation.ConclusionsThese data suggest that IRE1α is dispensable for photoreceptor development but important for photoreceptor homeostasis in aging retinas and for protecting against ER stress-mediated photoreceptor degeneration.

Feroz Aziz1, Tanmay Pandya1, Himanshu V Patel1, Paladugu Ramakrishna1, Kamal R Goplani1, Manoj Gumber1, Aruna V Vanikar2, Kamal Kanodia2, Pankaj R Shah1, Hargovind L Trivedi11Department of Nephrology and Transplantation Medicine; 2Department of Pathology, Lab Medicine, Transfusion Services and Immunohematology, G.R. Doshi and K.M. Mehta Institute of Kidney Diseases and Research Centre (IKDRC), Ahmedabad, Gujarat, IndiaAbstract: Renal involvement, which can rarely occur in echinococcosis, more commonly manifests as hydatid cyst of the kidney. Scattered case reports of nephrotic syndrome secondary to hydatid cyst in the liver or lung have been reported for over two decades. The glomerular picture varied from minimal change lesion to mesangiocapillary glomerulonephritis. We report a case of predominantly tubulointerstitial nephritis with mesangioproliferative glomerulonephritis in a patient with hepatic hydatid cyst which responded to cyst resection alone. Keywords: echinococcosis, hydatid cyst, kidney, nephrotic syndrome, tubulointerstitial nephritis