Posterior reversible encephalopathy syndrome in a child following hypovolemic shock: a case report.

Introduction and importance: Posterior reversible encephalopathy syndrome (PRES) is a condition that causes a wide range of clinical neurological manifestations like headache, seizures, visual changes, and altered mental sensations. It is diagnosed with the help of sequential neuroimaging findings. Manifestations may occur a few hours to months after the initial precipitating cause. In the pediatric population, the most common cause is hypertension caused by renal disease or different drugs. Case presentation: Here, the authors present the case of a 4-year-old boy with a significant medical history of acute gastroenteritis following hypovolemic shock that later developed white matter edema of the brain on T2-weighted MRI scans along with symptoms such as headache and vomiting. Here, the patient was managed symptomatically with antiepileptic medication as prophylaxis. Clinical discussion: PRES is a rare neurological diagnosis made in the child that presents with headache, vomiting, blurring of vision, and abnormal body movements, which have several etiology like hypertension, glomerulonephritis, organ transplant, drugs, and very rarely with hypovolemic shock. It is an acute reversible condition in which a person presents with visual disturbances, headaches, and seizures. Seizures present as a life-threatening situation, so antiepileptic drugs are used as early prophylaxis. Conclusion: PRES is a reversible neurological condition, and prognosis is typically favorable if recognized and treated early, with symptom improvement or resolution in a few days to several weeks. Complications of PRES develop if the disease is not treated promptly. Complications include focal neurologic deficits from ischemic injury and epilepsy.

Progressive multifocal leukoencephalopathy in the background of chlorambucil treated chronic lymphocytic leukemia: a case report from Nepal.

Introduction: Progressive multifocal leukoencephalopathy is a rare manifestation in itself. Although many immunosuppressive states are associated with the disease, its occurrence in the setting of chronic lymphocytic leukaemia treated with chemotherapy is seldom reported to date. Case presentation: A 67-year-old woman with known chronic lymphocytic leukaemia who was previously receiving chlorambucil treatment was identified as having progressive multifocal leukoencephalopathy; her prognosis is currently good. Clinical discussion: Although a rare disease in an immunocompromised setting, progressive multifocal leukoencephalopathy often leads to a grave outcome. However, the authors describe a case with a good prognosis to date. Conclusion: Progressive multifocal leukoencephalopathy should be in differentials in immunocompromised patients with dementia. Given that the later prognosis of the disease is unpredictable, an earlier diagnosis would be better for immunological reconstitution.

Stroke epidemiology and outcomes of stroke patients in Nepal: a systematic review and meta-analysis.

BACKGROUND: With an increasing burden of stroke, it is essential to minimize the incidence of stroke and improve stroke care by emphasizing areas that bring out the maximum impact. The care situation remains unclear in the absence of a national stroke care registry and a lack of structured hospital-based data monitoring. We conducted this systematic review and meta-analysis to assess the status of stroke care in Nepal and identify areas that need dedicated improvement in stroke care. METHODS: A systematic literature review was conducted to identify all studies on stroke epidemiology or stroke care published between 2000 and 2020 in Nepal. Data analysis was done with Statistical Package for Social Sciences (SPSS) and Comprehensive Meta-analysis (CMA-3). RESULTS: We identified 2533 studies after database searching, and 55 were included in quantitative and narrative synthesis. All analyses were done in tertiary care settings in densely populated central parts of Nepal. Ischemic stroke was more frequent (70.87%) than hemorrhagic (26.79%), and the mean age of stroke patients was 62,9 years. Mortality occurred in 16.9% (13-21.7%), thrombolysis was performed in 2.39% of patients, and no studies described thrombectomy or stroke unit care. CONCLUSION: The provision of stroke care in Nepal needs to catch up to international standards, and our systematic review demonstrated the need to improve access to quality stroke care. Dedicated studies on establishing stroke care units, prevention, rehabilitation, and studies on lower levels of care or remote regions are required.

Disseminated tuberculosis in an immunocompetent woman from the Himalayan region of Nepal: A case report.

Disseminated tuberculosis (TB) resulting from lymphohematogenous dissemination of Mycobacterium tuberculosis during primary infection or reactivation of latent disease is rare among young immunocompetent patients. Central nervous system TB (CNS TB) is one of the most challenging clinical diagnoses with high fatality. Here, we describe a young immunocompetent female with no known comorbidities initially presented with military pulmonary TB and later developed CNS TB. This presentation of disseminated TB in immunocompetent patient warrant early diagnosis and treatment.

Herpes simplex esophagitis in an immunocompetent host: a case report.

Esophagitis caused by Herpes Simplex virus is a well-recognized opportunistic infection in the immunocompromised or severely ill host. However, it is uncommon in otherwise immunocompetent host. It usually responds well to a course of acyclovir. We report a case of young female without any other immunocompromised state who presented with severe dysphagia. She was diagnosed endoscopically and later with histopathology and recovered well after a course of acyclovir.

Quantifying the Transverse-Electric-Dominant 260 nm Emission from Molecular Beam Epitaxy-Grown GaN-Quantum-Disks Embedded in AlN Nanowires: A Comprehensive Optical and Morphological Characterization.

There has been a relentless pursuit of transverse electric (TE)-dominant deep ultraviolet (UV) optoelectronic devices for efficient surface emitters to replace the environmentally unfriendly mercury lamps. To date, the use of the ternary AlGaN alloy inevitably has led to transverse magnetic (TM)-dominant emission, an approach that is facing a roadblock. Here, we take an entirely different approach of utilizing a binary GaN compound semiconductor in conjunction with ultrathin quantum disks (QDisks) embedded in AlN nanowires (NWs). The growth of GaN QDisks is realized on a scalable and low-cost Si substrate using plasma-assisted molecular beam epitaxy as a highly controllable monolayer growth platform. We estimated an internal quantum efficiency of ∼81% in a wavelength regime of ∼260 nm for these nanostructures. Additionally, strain mapping obtained by high-angle annular dark-field scanning transmission electron microscopy is studied in conjunction with the TE and TM modes of the carrier recombination. Moreover, for the first time, we quantify the TE and TM modes of the PL emitted by GaN QDisks for deep-UV emitters. We observed nearly pure TE-polarized photoluminescence emission at a polarization angle of ∼5°. This work proposes highly quantum-confined ultrathin GaN QDisks as a promising candidate for deep-UV vertical emitters.

Anti-leucine-rich Glioma-inactivated-1 Encephalitis with Faciobrachial Dystonic Seizures and Behavioral Problems: A Case Report.

Anti-Leucine-rich glioma-inactivated-1 encephalitis is a subtype of autoimmune encephalitis characterized by cognitive impairment, faciobrachial dystonic seizures, and behavioural changes. There is no reported case from Nepal. We report a case of a 54-year old male who presented with abnormal body movement, behavioural changes, rapid eye movement sleep behavioural changes, and cognitive decline. Investigations revealed magnetic resonance imaging findings of fluidattenuated inversion recovery intensity signal in bilateral temporal lobes with anti-leucine-rich glioma-inactivated-1 antibody in serum leading to diagnosis of anti-leucine-rich glioma-inactivated-1 encephalitis. He was treated with steroids and intravenous immunoglobulin. Timely diagnosis is vital to prevent complications and improve outcomes.

Titanium Carbide MXene Nucleation Layer for Epitaxial Growth of High-Quality GaN Nanowires on Amorphous Substrates.

Growing III-nitride nanowires on 2D materials is advantageous, as it effectively decouples the underlying growth substrate from the properties of the nanowires. As a relatively new family of 2D materials, MXenes are promising candidates as III-nitride nanowire nucleation layers capable of providing simultaneous transparency and conductivity. In this work, we demonstrate the direct epitaxial growth of GaN nanowires on Ti3C2 MXene films. The MXene films consist of nanoflakes spray coated onto an amorphous silica substrate. We observed an epitaxial relationship between the GaN nanowires and the MXene nanoflakes due to the compatibility between the triangular lattice of Ti3C2 MXene and the hexagonal structure of wurtzite GaN. The GaN nanowires on MXene show good material quality and partial transparency at visible wavelengths. Nanoscale electrical characterization using conductive atomic force microscopy reveals a Schottky barrier height of ∼330 meV between the GaN nanowire and the Ti3C2 MXene film. Our work highlights the potential of using MXene as a transparent and conductive preorienting nucleation layer for high-quality GaN growth on amorphous substrates.

Ultraviolet-to-blue color-converting scintillating-fibers photoreceiver for 375-nm laser-based underwater wireless optical communication.

Underwater wireless optical communication (UWOC) can offer reliable and secure connectivity for enabling future internet-of-underwater-things (IoUT), owing to its unlicensed spectrum and high transmission speed. However, a critical bottleneck lies in the strict requirement of pointing, acquisition, and tracking (PAT), for effective recovery of modulated optical signals at the receiver end. A large-area, high bandwidth, and wide-angle-of-view photoreceiver is therefore crucial for establishing a high-speed yet reliable communication link under non-directional pointing in a turbulent underwater environment. In this work, we demonstrated a large-area, of up to a few tens of cm2, photoreceiver design based on ultraviolet(UV)-to-blue color-converting plastic scintillating fibers, and yet offering high 3-dB bandwidth of up to 86.13 MHz. Tapping on the large modulation bandwidth, we demonstrated a high data rate of 250 Mbps at bit-error ratio (BER) of 2.2 × 10-3 using non-return-to-zero on-off keying (NRZ-OOK) pseudorandom binary sequence (PRBS) 210-1 data stream, a 375-nm laser-based communication link over the 1.15-m water channel. This proof-of-concept demonstration opens the pathway for revolutionizing the photodetection scheme in UWOC, and for non-line-of-sight (NLOS) free-space optical communication.

Perovskite-Based Artificial Multiple Quantum Wells.

Semiconductor quantum well structures have been critical to the development of modern photonics and solid-state optoelectronics. Quantum level tunable structures have introduced new transformative device applications and afforded a myriad of groundbreaking studies of fundamental quantum phenomena. However, noncolloidal, III-V compound quantum well structures are limited to traditional semiconductor materials fabricated by stringent epitaxial growth processes. This report introduces artificial multiple quantum wells (MQWs) built from CsPbBr3 perovskite materials using commonly available thermal evaporator systems. These perovskite-based MQWs are spatially aligned on a large-area substrate with multiple stacking and systematic control over well/barrier thicknesses, resulting in tunable optical properties and a carrier confinement effect. The fabricated CsPbBr3 artificial MQWs can be designed to display a variety of photoluminescence (PL) characteristics, such as a PL peak shift commensurate with the well/barrier thickness, multiwavelength emissions from asymmetric quantum wells, the quantum tunneling effect, and long-lived hot-carrier states. These new artificial MQWs pave the way toward widely available semiconductor heterostructures for light-conversion applications that are not restricted by periodicity or a narrow set of dimensions.

Direct Growth of Single Crystalline GaN Nanowires on Indium Tin Oxide-Coated Silica.

In this work, we demonstrated the direct growth of GaN nanowires on indium tin oxide (ITO)-coated fused silica substrate. The nanowires were grown catalyst-free using plasma-assisted molecular beam epitaxy (PA-MBE). The effect of growth condition on the morphology and quality of the nanowires is systematically investigated. Structural characterization indicates that the nanowires grow in the (0001) direction directly on top of the ITO layer perpendicular to the substrate plane. Optical characterization of the nanowires shows that yellow luminescence is absent from the nanowire's photoluminescence response, attributed to the low number of defects. Conductive atomic force microscopy (C-AFM) measurement on n-doped GaN nanowires shows good conductivity for individual nanowires, which confirms the potential of using this platform for novel device applications. By using a relatively low-temperature growth process, we were able to successfully grow high-quality single-crystal GaN material without the degradation of the underlying ITO layer.

High-power blue superluminescent diode for high CRI lighting and high-speed visible light communication.

We demonstrated a high-power (474 mW) blue superluminescent diode (SLD) on c-plane GaN-substrate for speckle-free solid-state lighting (SSL), and high-speed visible light communication (VLC) link. The device, emitting at 442 nm, showed a large spectral bandwidth of 6.5 nm at an optical power of 105 mW. By integrating a YAG-phosphor-plate to the SLD, a CRI of 85.1 and CCT of 3392 K were measured, thus suitable for solid-state lighting. The SLD shows a relatively large 3-dB modulation bandwidth of >400 MHz, while a record high data rate of 1.45 Gigabit-per-second (Gbps) link has been achieved below forward-error correction (FEC) limit under non-return-to-zero on-off keying (NRZ-OOK) modulation scheme. Our results suggest that SLD is a promising alternative for simultaneous speckle-free white lighting and Gbps data communication dual functionalities.

Wavy Architecture Thin-Film Transistor for Ultrahigh Resolution Flexible Displays.

A novel wavy-shaped thin-film-transistor (TFT) architecture, capable of achieving 70% higher drive current per unit chip area when compared with planar conventional TFT architectures, is reported for flexible display application. The transistor, due to its atypical architecture, does not alter the turn-on voltage or the OFF current values, leading to higher performance without compromising static power consumption. The concept behind this architecture is expanding the transistor's width vertically through grooved trenches in a structural layer deposited on a flexible substrate. Operation of zinc oxide (ZnO)-based TFTs is shown down to a bending radius of 5 mm with no degradation in the electrical performance or cracks in the gate stack. Finally, flexible low-power LEDs driven by the respective currents of the novel wavy, and conventional coplanar architectures are demonstrated, where the novel architecture is able to drive the LED at 2 × the output power, 3 versus 1.5 mW, which demonstrates the potential use for ultrahigh resolution displays in an area efficient manner.