Controlling Umklapp Scattering in a Bilayer Graphene Moiré Superlattice.

We present experimental findings on electron-electron scattering in two-dimensional moiré heterostructures with a tunable Fermi wave vector, reciprocal lattice vector, and band gap. We achieve this in high-mobility aligned heterostructures of bilayer graphene (BLG) and hBN. Around the half-full point, the primary contribution to the resistance of these devices arises from Umklapp electron-electron (Uee) scattering, making the resistance of graphene/hBN moiré devices significantly larger than that of non-aligned devices (where Uee is forbidden). We find that the strength of Uee scattering follows a universal scaling with Fermi energy and is nonmonotonically dependent on the superlattice period. The Uee scattering can be tuned with the electric field and is affected by layer polarization of BLG. It has a strong particle-hole asymmetry; the resistance when the chemical potential is in the conduction band is significantly lower than when it is in the valence band, making the electron-doped regime more practical for potential applications.

Charge-transfer-driven enhanced room-temperature ferromagnetism in BiFeO3/Ag nanocomposite.

We report observation of more than an order of magnitude jump in saturation magnetization in BiFeO3/Ag nanocomposite at room temperature compared to what is observed in bare BiFeO3nanoparticles. Using transmission electron microscopy together with energy dispersive x-ray spectra (which maps the element concentration across the BiFeO3/Ag interface) and x-ray photoelectron spectroscopy, we show that both the observed specific self-assembly pattern of BiFeO3and Ag nanoparticles and the charge transfer between Ag and O are responsible for such an enormous rise in room-temperature magnetization. The BiFeO3/Ag nanocomposites, therefore, could prove to be extremely useful for a variety of applications including biomedical.

A Rare Case of Fraser Syndrome with Partial Vaginal Agenesis and Its Successful Reconstructive Cosmetic Management: A Case Report.

Fraser syndrome is a rare disorder with autosomal recessive inheritance having a wide spectrum of phenotypic appearances. A fourteen-year-old female presented to us with a chief complaint of acute retention of urine without any cyclical abdominal pain with syndromic appearance. She had partial vaginal agenesis which was treated by successful reconstructive surgery by lotus petal flap technique followed by recanalisation. Objective of this report is to highlight the rare disease of Fraser syndrome along with successful rare surgical management.

Spectral-dependent electronic-photonic modeling of high-speed VCSEL-MMF links for optimized launch conditions.

We present spectral-dependent electronic-photonic modeling of vertical-cavity surface-emitting laser (VCSEL)-multimode fiber (MMF) links for next-generation high-speed interconnects. The beam coupling processes, between the VCSEL and the MMF and between the MMF and the photodetector (PD), are discussed, with spectral-dependent three-dimensional launch conditions analyzed. The model accounts for fiber effects on the transmission performance, specifically modal attenuation, dispersion, mode mixing, and mode partition noise. An advanced split-step small-segment (4-S) method simulates the signal evolution over the MMF with high accuracy and high efficiency. Experimental validation at 25 Gbps confirms the high accuracy of the VCSEL-MMF link model. The model reveals that larger radial offsets can further excite lower-order mode groups reducing the power distributed to higher-order groups when a tilted beam couples to the input fiber facet. With an optimized misalignment launch, the modal bandwidth is greatly improved by 3.8-fold compared to the conventional center launch. The model helps determine the optimum launch condition to improve link performance metrics such as transmission reach.

Cerebral Venous Sinus Thrombosis in Children: A Study from a Tertiary Care Hospital of Eastern India.

CONTEXT: Cerebral venous sinus (sinovenous) thrombosis (CVST) in childhood is a rare, but under recognized, disorder, typically of multifactorial etiology, with neurologic sequelae apparent in up to 40% of survivors and mortality approaching 10%. AIM: The aim of this study was to enlist the patients diagnosed as CVST younger than 14 years of age and to diagnose the etiology along with radiological correlation. SETTINGS AND DESIGN: This prospective clinical study was conducted for 2 years in the Department of Neurology, Srirama Chandra Bhanja Medical College & Hospital (SCBMCH), Cuttack, Odisha, India. MATERIALS AND METHODS: All the patients were enlisted in a prestructured format with detailed clinico-radiological evaluation. Treatment was performed according to recent guidelines. Outcome after 3 months was analyzed. Ethical clearance was obtained from institutional ethics committee. STATISTICAL ANALYSIS: Data were statistically analyzed using IBM SPSS Statistics for Windows, version 20 (IBM Corp., Armonk, N.Y., USA). RESULTS: The total number of patients included in the study was 30. Of them, six were neonates. The most common provocative factor was tuberculous meningitis. Phototherapy after neonatal hyperbilirubinemia was prominent cause in neonatal age group. Multiple sinus involvement was seen in most of the patients. Transverse sinus was the most common sinus to be involved. CONCLUSION: CVST is an underdiagnosed but important cause of stroke in childhood, occurring most often in the neonatal period. Mortality and morbidity are significant. Infections hyper coagulative disorders are the two primary associations. Magnetic resonance venography is the investigation of choice. Early diagnosis with management along with plan for secondary prevention can save from catastrophic consequences.

Series of Dopa Responsive Dystonia Masquerading as Other Diseases with Short Review.

Dopa-responsive dystonia (DRD) encompasses a group of clinically and genetically heterogeneous disorders that typically manifest as limb-onset, diurnally fluctuating dystonia presenting in early life and exhibits a robust and sustained response to levodopa treatment. DRD is one of the treatable dystonia syndromes of childhood. It starts with the involvement of lower limb and associated with characteristic diurnal variation. Many times it is misdiagnosed as cerebral palsy due to selective lower limb preference. We report a series of three cases of DRD which were previously misdiagnosed. The first case presented as myelopathy and other two were diagnosed as cerebral palsy. It is a treatable condition with very good response to drugs. Early diagnosis and adequate therapy can prevent from catastrophic complications.

AlN-SWCNT Metacomposites Having Tunable Negative Permittivity in Radio and Microwave Frequencies.

Discovery of plasmon resonance and negative permittivity in carbon allotropes at much lower frequencies than those of metals has evoked interest to develop random metacomposites by suitable means of addition of these dispersoids in an overall dielectric matrix. Random metacomposites have always the advantage for their easy preparation techniques over those of their regular arrayed artificial counterpart. However, thermal management during the heat generation by electromagnetic attenuation in metamaterials is not yet studied well. The present communication discusses the dielectric permittivities and loss parameters of aluminum nitride-single-wall carbon nanotube (AlN-SWCNT) composites considering high thermal conductivities of both materials. The composites are dense and have been prepared by a standard powder technological method using hot pressing at 1850 °C under a nitrogen atmosphere. Increase in the negative permittivity value with SWCNT concentration (1, 3, and 6 vol %) in the composites had been observed at low frequencies. Characterization of the materials with Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, and microstructure analysis by scanning and transmission electron microscopy (TEM) revealed the survivability of the SWCNTs and the nature of the matrix-filler interface. Plasmonic resonance following Drude's law could be observed at much lower plasma frequencies than that of pure SWCNT and for very little SWCNT addition. Exhibition of the negative permittivity has been explained with relation to the microstructure of the composites observed from field emission scanning electron micrographs (FESEM), TEM images, and the equivalent circuit model. High energy conversion efficiency is expected in these composites due to the possession of dual functionalities like high thermal conductivity as well as high negative permittivity, which should ensure the application of these materials in wave filter, cloaking device, supercapacitors, and wireless communication.

Organophosphorus-Induced Toxic Myeloneuropathy: Series of Three Adolescent Patients with Short Review.

Organophosphate (OP) poisoning is the most common poisoning in India, accounting for almost half of the hospital admissions due to poisoning. Delayed neuropathy is initiated by an attack on a nervous tissue esterase. Although uncommon, delayed neurotoxicity has been consistently reported in literature. This mechanism is implicated not only in damaging peripheral nervous system but also in causing central processes leading to myelopathy. We report a series of three adolescent patients who came to our hospital with delayed neurological manifestations of organophosphorus poisoning, which came out to be OP-induced myeloneuropathy after detailed analysis and evaluation.

Clinical Profile of Dengue Fever in Children: A Study from Southern Odisha, India.

Background. In India, dengue epidemics are becoming more frequent (WHO, 2008). The majority of dengue viral infections are self-limiting, but complications may cause high morbidity and mortality. Objectives. To assess the clinical profile of the dengue infection in children less than 14 years of age and to evaluate the outcomes of dengue fever from September 2013 to August 2015 at the Pediatric Department of Maharaja Krishna Chandra Gajapati Medical College, the largest tertiary care hospital of southern Odisha. Results. A total of 97 cases were classified into 84 (86.59%) nonsevere and 13 (13.40%) severe dengue cases. The most common age of presentation was above 11 yrs. The mean age of admission was 8.7 yrs. The most common presenting symptom was fever seen in 100% and hepatomegaly (43.8%), the most common physical finding. Gastrointestinal bleeding was markedly seen in severe dengue (76.9%). Elevation in aspartate transaminase (SGOT) was found in 47.42% and thrombocytopenia in 27.5%. The correlation between hepatomegaly and elevated SGOT was significant (P value 0.0346). Case fatality rate (CFR) was 1.03%. The mean duration of hospitalisation was 3.8 days. Conclusion. In children, if symptoms like fever, pain, rashes, and vomiting are associated with hepatomegaly and elevated SGOT in context of low TPC, a strong possibility of dengue fever is present, especially in an epidemic setting. Early suspicion and effective management can reduce the severity.

Case reports on atypical presentation of Plasmodium falciparum malaria in pediatric patients.

Variable atypical symptoms are commonly observed in malaria caused by Plasmodium falciparum especially in endemic tropical nations such as India. Nystagmus is observed following involvement of the cerebellum especially during the postrecovery phase. While psychotic features such as severe agitation, hallucination, paranoia may be the early symptoms of falciparum malaria among pediatric patients, urticaria with or without fever can be the initial manifestation of the disease. As the morbidity and mortality of severe malaria are very high in India, these atypical presentations should be considered during diagnosis. We believe our report on atypical cases of falciparum malaria will sensitize doctors and health personnel about rare presentations in children and help in early diagnosis and management to reduce the severity and death toll due to the disease.

Rubinstein-Taybi syndrome with agenesis of corpus callosum.

Rubinstein-Taybi syndrome (RSTS) is a rare genetic disorder with characteristic morphological anomaly. Our patient was a 4.5-year-old girl came with features like broad thumbs, downward slanting palpebral fissures and mental retardation. Systemic abnormalities such as repeated infection, seizure with developmental delay were also associated with it. She was having head banging behavior abnormal slurring speech, incoordination while transferring things from one hand to other. Galaxy of clinical pictures and magnetic resonance imaging report helped to clinch the diagnosis as a case of "RSTS with corpus callosal agenesis" which to the best of our knowledge has never been reported in past from India.

Robinow Syndrome: A Rare Diagnosis.

Robinow syndrome is a rare entity characterized by short stature and abnormalities of the head, face and external genitalia. It is otherwise called 'fetal face syndrome' due to its resemblance with fetal face. We present an eight-year-old female child who came with mesomelic short stature, abnormal facial features, multiple sets of teeth (both deciduous and permanent), pectus excavatum, umbilical hernia, limb abnormalities like shortening of fore arm, simian crease, broad thumbs and other fingers, clinodactyly, abnormal carrying angle, absent labia minora, absent clitoris. Apart from physical appearance she was having diversification of recti and umbilical hernia. Due to the several physical presentation mild systemic involvement it was diagnosed as autosomal dominant robinow syndrome. She is now on follow up and planned for a cosmetic surgery to repair facial defects.