Publications by authors named "Mahi Singh"

Lead poisoning in children has the potential for devastating neurodevelopmental consequences. There is significant socioeconomic disparity in children with lead poisoning. Specific lead chelation regimens have been approved for children by the US Food and Drug Administration, however in the United States, there has been a recent national shortage of the primary therapy, edetate calcium disodium (CaNa2 EDTA).

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Dual heterostructures integrating noble-metal and copper chalcogenide nanoparticles have attracted a great deal of attention in nonlinear optics, because coupling of their localized surface plasmon resonances (LSPRs) substantially enhances light-matter interactions through local-field effects. Previously, enhanced cascaded third-harmonic generation was demonstrated in Au/CuS heterostructures mediated by harmonically coupled surface plasmon resonances. This suggests a promising approach for extending nonlinear enhancement to higher harmonics by adding an additional nanoparticulate material with higher-frequency harmonic resonances to the hybrid films.

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We have studied the time-dependent optical properties of nanowaveguides containing an ensemble of noninteracting quantum emitters and interaction metallic nanoparticles. We have developed a theory for transient photoluminescence (PL) and exciton population density using the density matrix method. In our theory, we have included the effect of the dipole-dipole interaction (DDI) between metallic nanoparticles along with the effect of the surface plasmon polaritons (SPPs) created by metallic nanoparticles.

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A growing class of nonlinear materials employ the localized surface plasmonic resonance (LSPR) of nanoparticles to enhance harmonic generation. Material systems containing harmonically coupled metallic and semiconductor plasmonic nanoparticles have been shown to further increase performance. Here, we explore the effect of dual plasmonic interactions in bilayer CuS and Au nanoparticle films on third harmonic generation (THG).

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We have developed a theory of the quantum yield for plasmonic nanowaveguide where the cladding layer is made of an ensemble of quantum dots and the core layer consists of an ensemble of metallic nanoparticles. The bound states of the confined probe photons in the plasmonic nanowaveguide are calculated using the transfer matrix method based on the Maxwell equations. It is shown that the number of bound states in the nanowaveguide depends on the dielectric properties of the core and cladding layers.

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Although 9 of 10 of the world's children live in low- and middle-income countries (LMICs), and children constitute nearly half of the populations of these countries, far too little research has focused on child mental health in LMICs. The expansion of research in global health and global mental health over the past several decades has not yet been matched by new research in child and adolescent mental health in LMICs. It is time for that to change.

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A theory of the two-photon florescence for a metallic nanoshell in the presence of quantum emitters has been developed. The metallic nanoshell is made of a metallic nanosphere as a core and a dielectric material as a shell. An ensemble of quantum emitters is deposited on the surface of the dielectric shell.

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In this chapter, we explain why metallic nanomaterials are used in nanomedicine. We have shown that the electron density in metallic nanomaterials oscillates and creates electron density waves. When laser light falls on metallic nanoparticles, light interacts with electron density waves.

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We developed a theory for the fluorescence (FL) for quantum emitter and double metallic nanoshell dimer hybrids using the density matrix method. The dimer is made from two identical double metallic nanoshells, which are made of a dielectric core, a gold metallic shell and a dielectric spacer layer. The quantum emitters are deposited on the surface of the spacer layers of the dimers due to the electrostatic absorptions.

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We have studied energy absorption rate in a quantum dot-metallic nanosphere system embedded on a dielectric substrate. We applied a control field to induce dipole moments in the quantum dot and the metal nanosphere, and monitored the energy absorption using a probe field. These external fields induce dipole moments in the metal nanosphere and the quantum dot, and these two structures interact with one another via the dipole-dipole interaction.

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We have demonstrated energy transfer between a biological labelling dye (Alexa Fluor 405) and gold nanorods experimentally and theoretically. The fluorescence lifetime imaging microscopy and density matrix method are used to study a hybrid system of dye and nanorods under one- and two-photon excitations. Energy transfer between dye and nanorods via the dipole-dipole interaction is found to cause a decrease in the fluorescence lifetime change.

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Nonlinear two-photon absorption in a quantum dot-graphene nanoflake nanocomposite system has been investigated. An external laser field is applied to the nanocomposite to simultaneously observe two-photon processes in the quantum dot and excite localized surface plasmons in the graphene nanodisk. This resonance condition can be achieved by tuning the plasmon resonance frequency in the graphene nanoflake via electrostatic gating.

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We have investigated the second-harmonic generation (SHG) and dipole-dipole interaction in a quantum dot and metallic nanoparticle hybrid system. A strong probe field is applied to create two-photon absorption in the quantum dot and metallic nanoparticle. SHG photons and SHG surface plasmon polaritons are emitted by the quantum dot and metallic nanoparticle, respectively.

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The drivers of abnormal DNA methylation in human cancers include widespread aberrant splicing of the DNMT3B gene, producing abnormal transcripts that encode truncated proteins that may act as dominant negative isoforms. To test whether reduced Dnmt3b dosage can alter tumorigenesis, we bred Dnmt3b(+/-) mice to Eµ-Myc mice, a mouse model susceptible to B-cell lymphomas. Eµ-Myc/Dnmt3b(+/-) mice showed a dramatic acceleration of lymphomagenesis, greater even than that observed in Eµ-Myc mice that express a truncated DNMT3B isoform found in human tumors, DNMT3B7.

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It is known that surface-plasmon resonances of metallic nanoparticles can significantly enhance the field experienced by semiconductor quantum dots. In this paper we show that, when quantum dots are in the vicinity of metallic nanoparticles and interact with coherent light sources (laser fields), coherent exciton-plasmon coupling (quantum coherence effects) can increase the amount of the plasmonic field enhancement significantly. We also study how the coherent molecular resonances generated by such a coupling process are influenced by the self-renormalization of the plasmonic fields and the structural parameters of the systems, particularly the size and shape of the metallic nanoparticle.

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Thin films of Bi(x)Ce(3-x)Fe(5)O(12) with x = 0.7 and 0.8 compositions were prepared by using pulsed laser deposition.

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Simultaneous dislocation of the metacarpophalangeal and carpometacarpal joint has been previously reported. Floating metacarpals occur when the metacarpal head displaces volarly and the base displaces towards the dorsal side. A closed dislocation at both ends of the fifth ray is unusual.

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We study the variation of the energy absorption rate in a hybrid semiconductor quantum dot-metallic nanoparticle system doped in a photonic crystal. The quantum dot is taken as a three-level V-configuration system and is driven by two applied fields (probe and control). We consider that one of the excitonic resonance frequencies is near to the plasmonic resonance frequency of the metallic nanoparticle, and is driven by the probe field.

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Here, we study the resonant photonic states of photonic double quantum well (PDQW) heterostructures composed of two different photonic crystals. The heterostructure is denoted as B/A/B/A/B, where photonic crystals A and B act as photonic wells and barriers, respectively. The resulting band structure causes photons to become confined within the wells, where they occupy discrete quantized states.

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In this work, the absorption coefficient of a metallic photonic crystal doped with nanoparticles has been obtained using numerical simulation techniques. The effects of quantum interference and the concentration of doped particles on the absorption coefficient of the system have been investigated. The nanoparticles have been considered as semiconductor quantum dots which behave as a four-level quantum system and are driven by a single coherent laser field.

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We investigate the current-voltage relationship and the temperature-dependent conductance of nano-scale samples of poly(dA)-poly(dT) DNA molecules. A polaron hopping model has been used to calculate the I-V characteristic of nano-scale samples of DNA. This model agrees with the data for current versus voltage at temperatures greater than 100 K.

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The effect of the dipole-dipole interaction (DDI) on absorption processes has been investigated in photonic nanowires. They are manufactured by embedding a photonic crystal into another crystal. The embedded crystal is doped with an ensemble of three-level quantum dots.

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We conducted a randomized controlled trial comparing EUSOL (Edinburgh University Solution of Lime) and sugar as dressing agents in the treatment of traumatic wounds. Patients in both groups were matched for age and gender. We found EUSOL did better than sugar in terms of contraction of size of wound, presence of discharge, floor area covered with slough, formation of healthy granulation and early possibility of wound coverage.

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The aim of this prospective study was to assess the outcome of trochanteric fractures of the femur after external fixation in a group of elderly patients with high surgical risk. The study population consisted of 50 patients with trochanteric fractures of the femur and a mean age of 87 years who were classified by an anaesthetist as ASA 3 or 4 and considered not suitable for conventional fractures fixation. The fracture was fixed with an external fixator under spinal anaesthesia.

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Malignant peripheral nerve sheath tumors (MPNSTs) are the leading cause of death in young adults and are one of the most frequent non-rhabdomyosarcomatous soft tissue tumors in pediatric age. These tumors usually occur in young adults from a previously recognized neurofibroma, neurofibromatosis type 1 (NF1), with a noted change in size and pain. This child reached the age of 10 without the presence of the more commonly seen manifestations of NF1.

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