Publications by authors named "Rekha Shrestha"

Carnitine deficiency is a rare metabolic condition that can result in fasting hypoglycemia. Carnitine deficiency could be primary or secondary to other conditions. Among secondary causes, antiepileptics such as valproic acid have been incriminated.

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The energy storage performances of supercapacitors are expected to be enhanced by the use of nanostructured hierarchically micro/mesoporous hollow carbon materials based on their ultra-high specific surface areas and rapid diffusion of electrolyte ions through the interconnected channels of their mesoporous structures. In this work, we report the electrochemical supercapacitance properties of hollow carbon spheres prepared by high-temperature carbonization of self-assembled fullerene-ethylenediamine hollow spheres (FE-HS). FE-HS, having an average external diameter of 290 nm, an internal diameter of 65 nm, and a wall thickness of 225 nm, were prepared by using the dynamic liquid-liquid interfacial precipitation (DLLIP) method at ambient conditions of temperature and pressure.

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The fabrication of various sensing devices and the ability to harmonize materials for a higher degree of organization is essential for effective sensing systems. Materials with hierarchically micro- and mesopore structures can enhance the sensitivity of sensors. Nanoarchitectonics allows for atomic/molecular level manipulations that create a higher area-to-volume ratio in nanoscale hierarchical structures for use in ideal sensing applications.

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Nanoarchitectonics integrates nanotechnology with numerous scientific disciplines to create innovative and novel functional materials from nano-units (atoms, molecules, and nanomaterials). The objective of nanoarchitectonics concept is to develop functional materials and systems with rationally architected functional units. This paper explores the progress and potential of this field using biomass nanoarchitectonics for supercapacitor applications as examples of energetic materials and devices.

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The electrical double-layer supercapacitance performance of the nanoporous carbons prepared from the (Amala) seed by chemical activation using the potassium hydroxide (KOH) activator is reported. KOH activation was carried out at different temperatures (700-1000 °C) under nitrogen gas atmosphere, and in a three-electrode cell set-up the electrochemical measurements were performed in an aqueous 1 M sulfuric acid (HSO) solution. Because of the hierarchical pore structures with well-defined micro- and mesopores, seed-derived carbon materials exhibit high specific surface areas in the range of 1360 to 1946 m g, and the total pore volumes range from 0.

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Congenital absence of pericardium is an exceedingly rare condition with a prevalence of 0.002%-0.004%.

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IgG4-related disease (IgG4-RD) is an immune-mediated inflammatory condition of unknown etiology characterized by invasion of tissue by IgG4-producing plasma cells. It can affect almost any organ system, but central nervous system involvement is a rare occurrence. A careful clinicopathological correlation is required to establish the diagnosis.

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Biomass-derived activated carbon materials with hierarchically nanoporous structures containing nitrogen functionalities show excellent electrochemical performances and are explored extensively in energy storage and conversion applications. Here, we report the electrochemical supercapacitance performances of the nitrogen-doped activated carbon materials with an ultrahigh surface area prepared by the potassium hydroxide (KOH) activation of the (Lotus) seed in an aqueous electrolyte solution (1 M sulfuric acid: HSO) in a three-electrode cell. The specific surface areas and pore volumes of Lotus-seed-derived carbon materials carbonized at a different temperatures, from 600 to 1000 °C, are found in the range of 1059.

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Of the available environmentally friendly energy storage devices, supercapacitors are the most promising because of their high energy density, ultra-fast charging-discharging rate, outstanding cycle life, cost-effectiveness, and safety. In this work, nanoporous carbon materials were prepared by applying zinc chloride activation of lotus seed powder from 600 °C to 1000 °C and the electrochemical energy storage (supercapacitance) of the resulting materials in aqueous electrolyte (1M HSO) are reported. Lotus seed-derived activated carbon materials display hierarchically porous structures comprised of micropore and mesopore architectures, and exhibited excellent supercapacitance performances.

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Ionic self-assembly is a simple yet powerful method to obtain robust nanostructures. Herewith, we use mixtures of oppositely-charged porphyrins that can act as mesogens to form chromonic liquid crystals in water, i.e.

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We have demonstrated a highly sensitive moisture sensor that can detect water molecules, in addition to water droplets, and therefore, can predict dew condensation with high accuracy and high speed before the formation of water droplets, showing a better performance than a commercial hygrometer. Additionally, the dependence of the output response from the sensor on factors, such as the cooling rate of the sensor's surface and the vapor pressure in the chamber, that affect the performance of the moisture sensor has been clarified. The output response showed a clear dependence on the variation in cooling rate, as well as the vapor pressure.

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Nanoporous activated carbons-derived from agro-waste have been useful as suitable and scalable low-cost electrode materials in supercapacitors applications because of their better surface area and porosity compared to the commercial activated carbons. In this paper, the production of nanoporous carbons by zinc chloride activation of Washnut seed at different temperatures (400-1000 °C) and their electrochemical supercapacitance performances in aqueous electrolyte (1 M HSO) are reported. The prepared nanoporous carbon materials exhibit hierarchical micro- and meso-pore architectures.

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Background: Sickle cell and thalassemia are the inherited disorders of globin chain synthesis, and are the most common monogenic disease worldwide. This study aims to find the distribution of hemoglobinopathies (sickle cell and thalassemia) cases in Nepal using laboratory based data.

Methods: A retrospective study was carried out at five different sites of Nepal Government that uses capillary electrophoresis for screening of hemoglobin disorders from January 2019 to March 2019.

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Nanoporous activated carbon materials derived from agro-wastes could be suitable low-cost electrode materials for high-rate performance electrochemical supercapacitors. Here we report high surface area nanoporous carbon materials derived from Lapsi seed agro-waste prepared by zinc chloride (ZnCl) activation at 700 °C. Powder X-ray diffraction (pXRD) and Raman scattering confirmed the amorphous structure of the resulting carboniferous materials, which also incorporate oxygen-containing functional groups as confirmed by Fourier transform infrared (FTIR) spectroscopy.

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Article Synopsis
  • High-performance supercapacitors require carbon materials with a high surface area and large pore volume featuring hierarchical nanoporous structures.
  • Such materials can be made from organic precursors like synthetic biomass or agricultural waste rich in carbon.
  • The review covers recent methods for creating these hierarchical porous carbons, including direct conversion from fullerene nanomaterials, templating routes, and carbonization of biomass, emphasizing their potential for supercapacitor applications.
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A moisture sensor has been reported that detects invisibly small water droplets and distinguishes their particle size with high accuracy and high speed. This sensor uses narrow lines of dissimilar metals as electrodes, arranged with gaps of 0.5 to 10 μm.

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Here we report the aromatic vapor sensing performance of bitter melon shaped nanoporous fullerene C crystals that are self-assembled at a liquid-liquid interface between isopropyl alcohol and C solution in dodecylbenzene at 25 °C. Average length and center diameter of the crystals were ca. 10 μm and ~2 μm, respectively.

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A hierarchical heterostructure composed of silver nanoparticles (Ag-NPs: average diameter ∼10 nm) on fullerene nanorods (FNRs: average length ∼11 μm and average diameter ∼200 nm) was fabricated using a simple solution route. It was used as an effective single particle freestanding surface enhanced Raman scattering (SERS) substrate for the detection of target molecules (Rhodamine 6G: R6G). FNRs were formed ultra-rapidly (formation process completed in a few seconds) at a liquid-liquid interface of methanol and C60/mesitylene solution then Ag-NPs were grown directly on the surfaces of the FNRs by treatment with a solution of silver nitrate in ethanol.

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This report describes the controlled viscosity changes of photoresponsive reverse wormlike micellar systems formed by soybean lecithin (SoyPC), d-ribose, and azobenzene derivatives in decane. UV light irradiation produces a significant (150-fold) decrease in solution viscosity by triggering a structural transformation of the wormlike micelles. Subsequent visible light irradiation leads to recovery of the initial micellar structure and elevated solution viscoelasticity.

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Fullerene C microbelts were fabricated using the liquid-liquid interfacial precipitation method and converted into quasi 2D mesoporous carbon microbelts by heat treatment at elevated temperatures of 900 and 2000 °C. The carbon microbelts obtained by heat treatment of fullerene C microbelts at 900 °C showed excellent electrochemical supercapacitive performance, exhibiting high specific capacitances ca. 360 F g (at 5 mV s) and 290 F g (at 1 A g) because of the enhanced surface area and the robust mesoporous framework structure.

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A method for controlling the self-assembly of fullerene C molecules into nanotubules in the fcc phase, devoid of entrapped solvent, has been established in a thin film microfluidic device. The micron length C nanotubules, with individual hollow diameters of 100 to 400 nm, are formed under continuous flow processing during high shear micromixing of water and a toluene solution of the fullerene, in the absence of surfactant, and without the need for further down-stream processing. TEM revealed pores on the surface of the nanotubes, and the isolated material has a much higher response to small molecule sensing than that for analogous material formed using multistep batch processing.

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We have investigated the textural properties, electrochemical supercapacitances and vapor sensing performances of bamboo-derived nanoporous carbon materials (NCM). Bamboo, an abundant natural biomaterial, was chemically activated with phosphoric acid at 400 °C and the effect of impregnation ratio of phosphoric acid on the textural properties and electrochemical performances was systematically investigated. Fourier transform-infrared (FTIR) spectroscopy confirmed the presence of various oxygen-containing surface functional groups (i.

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Carbon nanofibers (CNFs) with high surface area (820 m/g) have been successfully prepared by a nanocasting approach using silica nanofibers obtained from chromonic liquid crystals as a template. CNFs with randomly oriented graphitic layers show outstanding electrochemical supercapacitance performance, exhibiting a specific capacitance of 327 F/g at a scan rate of 5 mV/s with a long life-cycling capability. Approximately 95% capacitance retention is observed after 1000 charge-discharge cycles.

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Here, we report the structural and morphological modulation of fullerene C crystals induced by nonionic surfactants diglycerol monolaurate (CG) and monomyristate (CG). C crystals synthesized at a liquid-liquid interface comprising isopropyl alcohol (IPA) and a saturated solution of C in ethylbenzene (EB) exhibited a one-dimensional (1D) morphology with well-defined faceted structure. Average length and diameter of the faceted rods were ca.

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Conjugated polymers with strong photophysical properties are used in many applications. A homopolymer (P1) and five new low band gap copolymers based on 4,4'-difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY) and acceptors 3,6-dithienyldiketopyrrolopyrrole (P2), phthalimide (P3), benzotriazole (P4), 4,7-dithienyl[1,2,3]triazolo[4,5g]quinoxaline (P5), and 2,5-dithienylthieno[3,4-b]pyrazine (P6) were prepared by means of Sonogashira polymerization. The characterization of polymers by using (1) H NMR, absorption, and emission spectroscopy is discussed.

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