High-performance one-dimensional halide perovskite crossbar memristors and synapses for neuromorphic computing.

Despite impressive demonstrations of memristive behavior with halide perovskites, no clear pathway for material and device design exists for their applications in neuromorphic computing. Present approaches are limited to single element structures, fall behind in terms of switching reliability and scalability, and fail to map out the analog programming window of such devices. Here, we systematically design and evaluate robust pyridinium-templated one-dimensional halide perovskites as crossbar memristive materials for artificial neural networks. We compare two halide perovskite 1D inorganic lattices, namely (propyl)pyridinium and (benzyl)pyridinium lead iodide. The absence of conjugated, electron-rich substituents in PrPyr+ prevents edge-to-face type π-stacking, leading to enhanced electronic isolation of the 1D iodoplumbate chains in (PrPyr)[PbI3], and hence, superior resistive switching performance compared to (BnzPyr)[PbI3]. We report outstanding resistive switching behaviours in (PrPyr)[PbI3] on the largest flexible crossbar implementation (16 × 16) to date - on/off ratio (>105), long term retention (105 s) and high endurance (2000 cycles). Finally, we put forth a universal approach to comprehensively map the analog programming window of halide perovskite memristive devices - a critical prerequisite for weighted synaptic connections in artificial neural networks. This consequently facilitates the demonstration of accurate handwritten digit recognition from the MNIST database based on spike-timing-dependent plasticity of halide perovskite memristive synapses.

Ion-Mediated Recombination Dynamics in Perovskite-Based Memory Light-Emitting Diodes for Neuromorphic Control Systems.

Neuromorphic devices can help perform memory-heavy tasks more efficiently due to the co-localization of memory and computing. In biological systems, fast dynamics are necessary for rapid communication, while slow dynamics aid in the amplification of signals over noise and regulatory processes such as adaptation- such dual dynamics are key for neuromorphic control systems. Halide perovskites exhibit much more complex phenomena than conventional semiconductors due to their coupled ionic, electronic, and optical properties which result in modulatable drift, diffusion of ions, carriers, and radiative recombination dynamics. This is exploited to engineer a dual-emitter tandem device with the requisite dual slow-fast dynamics. Here, a perovskite-organic tandem light-emitting diode (LED) capable of modulating its emission spectrum and intensity owing to the ion-mediated recombination zone modulation between the green-emitting quasi-2D perovskite layer and the red-emitting organic layer is introduced. Frequency-dependent response and high dynamic range memory of emission intensity and spectra in a LED are demonstrated. Utilizing the emissive read-out, image contrast enhancement as a neuromorphic pre-processing step to improve pattern recognition capabilities is illustrated. As proof of concept using the device's slow-fast dynamics, an inhibition of the return mechanism is physically emulated.

Nomophobia: A rising concern among Indian students.

BACKGROUND: Nomophobia is defined as "the fear of being without a mobile phone or unable to use it." Nowadays, it is considered a modern age phobia. It is to be considered as a form of behavioral addiction. AIM: This study aims to determine the level of nomophobia in the Indian population aged between 15 and 35 years. MATERIALS AND METHODS: A personalized questionnaire was designed in the Google Forms and distributed among the targeted audience. The questionnaire contained three parts: consent letter, sociodemographic details, and nomophobia questionnaire. A total of 2061 valid responses were analyzed in SPSS software. RESULTS: Out of 2061, 52.9% of the respondents were male and 47.1% were female. 92.2% of the respondents were between 18 and 24 years of age group. Moreover, 79.1% of the respondents are undergraduate or pursuing their graduation. 35.5% of the respondents were from metropolitan city, 38.8% were from an urban city, and 12.15% were from a semiurban city, while the rest 13.6% were from rural areas. 74.8% of the respondents were moderate nomophobic, 18.9% were severe nomophobic, and 6.3% were mild nomophobic. CONCLUSION: In this study, we observed that nomophobia is moderate to severe and that our "physical, mental, and social health" has a major concern.

How I do it? Endoscopic discectomy using a new trocar "Endospine Plus" for lumbar prolapsed intervertebral disc.

BACKGROUND: Endoscopic spine surgery is a promising minimally invasive technique and use of trocars like Metrx (Neurosurgery 51(5):S129-36, 2002), Destandau (Neurol Res 21:39-42, 1999), and Easy go (Acta Neurochir (Wien) 151:1027­33, 2009) has revolutionized this field. However, the steep learning curve makes this procedure elusive to many parts of the world. METHODS: The authors describe the technique of pure endoscopic discectomy using a specialized trocar devised by the senior author "Endospine Plus" which makes the technique easy to learn along with the advantages and complications of the procedure. CONCLUSIONS: Endoscopic lumbar discectomy is a safe and effective technique for the treatment of prolapsed intervertebral disc.

A unique case of concomitant intra and extracranial Hansen's disease.

Leprosy is a debilitating disease that usually involves the peripheral branches of the cranial nerves leading to anesthetic/hypoesthetic skin lesions and thickened peripheral nerves. However, the involvement of the central nervous system (CNS) is extremely rare. To the best of the author's knowledge, the involvement of the cranial nerve nuclei by leprosy has not been reported in the literature and the present case is the first report of involvement of the facial nerve nuclei by leprosy.

Late onset leptomeningeal and whole spine metastasis from supratentorial Glioblastoma multiforme: An uncommon manifestation of a common tumor.

Glioblastoma multiforme (GBM) is one of the most common and aggressive primary brain tumors, composing 12-20% of all the intracranial tumors in adults with a highly malignant course and average life expectancy of approximately 12-14 months following initial diagnosis. Leptomeningeal or intramedullary metastasis from primary GBM is a rare phenomenon with a poor prognosis. We present a rare case of GBM with late onset intramedullary, extramedullary, as well as leptomeningeal spinal metastasis.

Intracranial periventricular supratentorial intraparenchymal schwannoma.

BACKGROUND: Intraparenchymal schwannomas in the central nervous system are very rare. Because most of these are benign, complete excision is the treatment of choice. Further, their radiological findings are difficult to differentiate from glioma. Because Schwann cells are not indigenous to cerebral parenchyma, a lot of speculation has been attached to their origin. CASE DESCRIPTION: We report one such rare case of a 17-year-old male who presented to us with a history of headache and vomiting. Neuroradiological findings were suggestive of left temporoparietal solid cystic lesion with enhancement of solid component, suggestive of high grade glioma. CONCLUSION: Intraoperative impression was that of a low-grade glioma but histopathological features were represented as schwannoma.