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Dive into the research topics where Bibek Jyoti Borah is active.

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Featured researches published by Bibek Jyoti Borah.


Green Chemistry | 2011

Stabilization of Cu(0)-nanoparticles into the nanopores of modified montmorillonite: An implication on the catalytic approach for “Click” reaction between azides and terminal alkynes

Bibek Jyoti Borah; Dipanka Dutta; Partha Pratim Saikia; Nabin C. Barua; Dipak Kumar Dutta

In situ generation of Cu(0)-nanoparticles in the nanopores of modified montmorillonite and their catalytic activity in 1,3-dipolar cycloaddition reactions between azides and terminal alkynes to synthesise 1,2,3-triazoles have been carried out. The modification of montmorillonite was carried out by activation with H2SO4 under controlled conditions for generating nanopores to act as a “host” for the Cu(0)-nanoparticles, which is executed by successful loading of Cu(CH3COO)2 metal precursor through an incipient wetness impregnation technique followed by reduction with NaBH4. A TEM study reveals that Cu(0)-nanoparticles within the size range of 0–10 nm are evenly distributed on the support. The synthesized Cu(0)-nanoparticles exhibit face centered cubic (fcc) lattice geometry and serve as an efficient green catalyst for the “Click” azide–alkyne cycloaddition to afford highly regioselective 1,4-disubstituted 1,2,3-triazoles with excellent yields and selectivity in aqueous medium. The nanocatalysts can be recycled and reused several times without significant loss of their catalytic activity.


Catalysis Science & Technology | 2014

Efficient three-component coupling reactions catalyzed by Cu0-nanoparticles stabilized on modified montmorillonite

Bibek Jyoti Borah; Subrat Jyoti Borah; Lakshi Saikia; Dipak Kumar Dutta

The in situ generation of Cu0-nanoparticles into the nanopores of modified montmorillonite and their catalytic performance in the three component (A3) coupling reactions of aldehyde, amine and alkyne to synthesize propargylamines have been described here. The modification of montmorillonite was carried out with HCl under controlled conditions for generating nanopores into the matrix and these pores act as a “host” for the in situ generation of Cu0-nanoparticles. The Cu0-nanoparticles were generated in the nanopores of the acid activated clay mineral matrix by the successful loading of a Cu(CH3COO)2 metal precursor using an incipient wetness impregnation technique followed by reduction with NaBH4. The TEM study reveals that Cu0-nanoparticles of below 10 nm in size are evenly distributed on the support. The synthesized Cu0-nanoparticles exhibit a face centered cubic (fcc) lattice. The Cu0-nanoparticles serve as an efficient green and heterogeneous catalyst for three-component coupling via C–H alkyne-activation to synthesize propargylamines with excellent yields (82–94%) and 100% selectivity under mild reaction conditions without requiring any additives or an inert atmosphere. The nanocatalysts can be recycled and reused several times without significant loss of their catalytic activity.


Catalysis Science & Technology | 2014

Efficient one-pot synthesis of propargylamines catalysed by gold nanocrystals stabilized on montmorillonite

Bibek Jyoti Borah; Subrat Jyoti Borah; Kokil Saikia; Dipak Kumar Dutta

Size selective Au0-nanoparticles were generated in situ in the nanopores of modified montmorillonite. The modification of montmorillonite was carried out with HCl under controlled conditions for generating nanopores (less than 8 nm) in the matrix and these nanopores acted as “hosts” for the in situ generation of Au0-nanoparticles. The synthesis consisted of impregnation of the acid-activated montmorillonite with HAuCl4 aqueous solution followed by reduction with NaBH4. The synthesised Au0-nanoparticles crystallized in the face centred cubic lattice were single crystals with a preferential growth direction along the (111) plane. A N2 adsorption–desorption study revealed specific surface areas of 327–579 m2 g−1, large specific pore volumes ~0.7 cm3 g−1, and pore diameters of 0–10 nm of the support. TEM, FESEM and X-ray studies indicate that Au0-nanoparticles of 0–10 nm were evenly distributed on the support which then serves as an efficient green catalyst for the one-pot, three-component coupling of an aldehyde, an amine and an alkyne via C–H alkyne-activation to synthesize propargylamines with 82–94% yield and 100% selectivity under mild reaction conditions. The nanocatalysts can be recycled and reused several times without significant loss of their catalytic activity.


Green Chemistry | 2016

Stabilized Fe3O4 magnetic nanoparticles into nanopores of modified montmorillonite clay: a highly efficient catalyst for the Baeyer–Villiger oxidation under solvent free conditions

Pallab Kumar Saikia; Podma Pollov Sarmah; Bibek Jyoti Borah; Lakshi Saikia; Kokil Saikia; Dipak Kumar Dutta

In situ generation of Fe3O4 magnetic nanoparticles (Fe3O4@AT-mont.) into the nanopores of modified montmorillonite (AT-mont.) clay has been carried out. Modification of the montmorillonite was done by acid (4 M HCl) activation under controlled conditions for generating nanopores, which act as a “host” for the Fe3O4 nanoparticles. The synthesized Fe3O4@AT-mont. was characterized by PXRD, TEM, SEM-EDX, XPS, VSM and surface area analysis. The average particle size of Fe3O4 nanoparticles was found to be around 10 nm and exhibit a face centered cubic (fcc) lattice geometry. Fe3O4@AT-mont. showed efficient catalytic activity for the Baeyer–Villiger oxidation of various cyclic and aromatic ketones in the presence of hydrogen peroxide as an oxidant at room temperature under solvent free conditions and exhibited conversion of up to 98%. The catalyst was magnetically recovered and recycled up to the third run without any significant loss of efficiency.


Catalysis Reviews-science and Engineering | 2015

Recent Advances in Metal Nanoparticles Stabilization into Nanopores of Montmorillonite and Their Catalytic Applications for Fine Chemicals Synthesis

Dipak Kumar Dutta; Bibek Jyoti Borah; Podma Pollov Sarmah

Metal nanoparticles supported montmorillonite with innovative characteristics has led to a new generation of heterogeneous “nanocatalyst.” Such catalysts are superior to the conventional catalysts because of several factors like: higher surface area; higher activity; higher selectivity and longer life and thus, developing a newer type of sustainable environmentally friendly catalysts. Metal clay supported nanocatalysts may find a wide range of applications in the area of fine and bulk chemical industries, pharmaceuticals, fuel cell, petroleum refineries, environmental catalysis, and many other fields. This article summarizes the recent advances in the synthesis and characterization of metal nanoparticles supported on modified montmorillonite and their catalytic applications for fine chemicals synthesis.Metal nanoparticles supported montmorillonite with innovative characteristics has led to a new generation of heterogeneous “nanocatalyst.” Such catalysts are superior to the conventional catalysts because of several factors like: higher surface area; higher activity; higher selectivity and longer life and thus, developing a newer type of sustainable environmentally friendly catalysts. Metal clay supported nanocatalysts may find a wide range of applications in the area of fine and bulk chemical industries, pharmaceuticals, fuel cell, petroleum refineries, environmental catalysis, and many other fields. This article summarizes the recent advances in the synthesis and characterization of metal nanoparticles supported on modified montmorillonite and their catalytic applications for fine chemicals synthesis.


New Journal of Chemistry | 2016

Aromatic ring hydrogenation catalysed by nanoporous montmorillonite supported Ir(0)-nanoparticle composites under solvent free conditions

Prabin Das; Podma Pollov Sarmah; Bibek Jyoti Borah; Lakshi Saikia; Dipak Kumar Dutta

Ir(0)-nanoparticles (Ir-NPs) were synthesized into the nanopores of modified montmorillonite clay by incipient wetness impregnation of IrCl3 followed by reduction with ethylene glycol. The activation of the montmorillonite clay was carried out by treatment with HCl under controlled conditions to increase the surface area by generating nanopores which act as host for the metal nanoparticles. The synthesized Ir-NP–montmorillonite composites were characterized by N2-sorption, powder XRD, SEM, EDS, TEM, XPS, etc. The composites exhibit high surface area of 327 m2 g−1 and the Ir-NPs with size around 4 nm are uniformly distributed on the support. The Ir-NPs show efficient catalytic activity in aromatic ring hydrogenation under solvent free conditions with maximum conversion up to 100% and Turn Over Frequency (TOF) up to 79 h−1. The catalyst can be easily separated by simple filtration and remained active for several runs without significant loss of catalytic efficiency.


Journal of Nanomedicine & Nanotechnology | 2014

Metal nanoparticles for green and sustainable catalytic applications

Dipak Kumar Dutta; Bibek Jyoti Borah

I this paper, chirality organization of peptide bioconjugates through hydrogen bondings is described. A variety of ferrocenepeptide bioconjugates as bioorganometallics are designed to induce chirality-organized structures of peptides. The ferrocene is recognized to serves as a reliable organometallic scaffold for the construction of protein secondary structures via intramolecular hydrogen bondings, wherein the attached dipeptide chains are constrained within the appropriate dimensions. The configuration and sequence of the amino acids are demonstrated to play an important role in the construction of the chirality-organized bio-inspired systems under controlled hydrogen bonds. Another interesting feature of ferrocene-dipeptide bioconjugates is their strong tendency to self-assemble through the contribution of available hydrogen bonding donors for helical architectures in solid states. The intramolecular hydrogen bondings and chirality of the histidyl pendant groups on the 2,6-pyridinedicarboxamide scaffold are performed to allow induction of the chiral helicity, creating the leftor righthanded helical molecular assembly by the connection of each helical molecule through continuous intermolecular hydrogen bonds. A urea molecular scaffold is introduced into dipeptides to afford the formation of the chiral hydrogen-bonded duplex, wherein each hydrogen-bonded duplex is connected by continuous intermolecular hydrogen bonds to form a double helix-like arrangement.A transition metal oxides, vanadium oxides have received relatively modest attention for supercapacitor applications. Yet, this material is abundant, relatively inexpensive and offers several oxidation states which can provide a broad range of redox reactions suitable for supercapacitor operation. Electrochemical supercapacitors based on nanostructured vanadium oxide (V2O5 ) suffer from relatively low energy densities as they have low surface area and poor electrical conductivities. To overcome these problems, we developed a layer by layer assembly (LBL) technique in which a graphene layer was alternatively inserted between MWCNT films coated with ultrathin (3 nm) V2O5 . The insertion of a conductive spacer of graphene between the MWCNT films coated with V2O5 not only prevents agglomeration between the MWCNT films but also substantially enhances the specific capacitance by 67 %, to as high as ~2,590 Fg-1. Furthermore, the LBL assembled multilayer supercapacitor electrodes exhibited excellent cycling performance > 97 % capacitance retention over 5,000 cycles and a high energy density of 96 Whkg-1 at a power density of 800 Wkg-1. Our approach clearly offers an exciting opportunity for enhancing the device performance of metal oxide-based electrochemical supercapacitors suitable for next-generation flexible energy storage devices by employing a facile LBL assembly.C Heart Disease (CHD) affects over 16 million people in US and is the largest killer in the western world. Overwhelming evidence indicates that increasing levels of circulating high-density lipoprotein (HDL) significantly decreases occurrence of coronary artery disease. Atheroprotective properties of HDL result from its ability to efflux excess of cholesterol from macrophages in plaques and transport it to the liver for excretion. Infusion of synthetic HDL (sHDL) nanoparticles to facilitate cholesterol removal from hardened arteries has been proven effective in phase 2 clinical studies. Synthetic HDL is a nanoparticle (~8-12 nm) composed of a lipid membrane-like bilayer wrapped around by a “belt” of amphipathic helices of Apolipoprotein A-I (ApoA-I). Development of sHDL as therapeutic drugs has been difficult owing to the very large doses (~1-8 g) required to attain clinical endpoints. Administration of high doses results in toxicity due to nanoparticle and protein impurities, and further requires manufacture of high quantities of recombinant ApoA-I, which is both technically difficult and costly. The focus of this research is discovery of novel ApoA-I mimic peptides, optimization of lipid composition of sHDL and use of these nanoparticles for atherosclerosis imaging and drug delivery. By understanding of biophysics of ApoA-I peptide binding to lipid membranes we are able to produce highly pure sHDL of homogeneous size, which are capable of mimicking the function of endogenous HDL. We have found that by optimizing lipid composition, the potency of sHDL in vitro and in vivo could be increased 3-fold. In addition, sHDL composition affected anti-inflammatory properties of nanoparticles and their remodeling in human plasma. Hence, understanding the mechanisms of how composition alters efficacy and safety of sHDL is critical for successful clinical translation of this novel class of cardiovascular drugs to the clinic.G an atom thick of carbon semimetal, has attracted a great deal of attention due to its new properties and promising applications which might have impact in new electronic devices, novel composite materials, innovative sensors, etc. However, graphene it is not alone, there is also hexagonal boron nitride (H-BN) a layered insulator which can be combined with graphene to form new hetero layer materials. Moreover, there are flat layered structures made out of transition metal dichacogenides (TMD) such as MoS2, WS2, MoSe2, WSe2, NbS2, NbSe2, WTe2, etc., which can behave as semiconductors or metals depending on the atoms involved. Interestingly, one monolayer of a semiconducting TMD exhibits a direct band gap which vanishes when adding another layer, thus producing an indirect band gap bilayer material. Since monolayer semiconducting TMD, with trigonal prismatic structure, do not possess center of inversion, exhibit valley polarization effects which envisage their application in non-linear optics and in a new field called valley-tronics. In this talk, theoretical and experimental efforts to shed light on the comportment of TMDs will be provided. First, the main synthesis methods of monolayer TMDs such as exfoliation, chemical vapor transport and chemical vapor deposition will be studied along with their main challenges. Second, the role of defects and doping of TMDs will be analyzed, and finally, first principles calculations to understand their optoelectronic behavior and Raman scattering will be also explained.D containing rigid conjugated backbones were prepared by a convergent method where the attachment of dendritic branches and the extension of phenylene-ethynylene units were alternatively manipulated on the structure of AB2 substituted diphenylacetylene. These dendrimer structures were applied for the construction of nanoscale light-harvesting antennas and charge-separating systems. The conjugated network inside the dendritic structure was shown to play an important role not only as a scaffold for the precise arrangement of functional groups but also as a mediator in both the photoinduced energyand electron-transfer processes. In addition, we report a novel methodology for the construction of nanoscale covalent assemblies with rigid conjugated backbones using dendrimers as modular building blocks. The method was successfully applied to construct a square assembly (diagonal distance of ca. 11 nm) and a linear octamer (48 nm). Spectroscopic measurements establish that the octamer prefers to have folded conformation. These examples demonstrate advantage of the dendrimer with conjugated backbones for the construction of nanoscale molecular devices.Q technology is a promising route for the realization of high-performance photovoltaic devices. The tuneability of optoelectronic properties of quantum dots makes them applicable for a range of novel device designs that offer power conversion efficiencies well in excess of conventional limits. The optoelectronic performance of the QDs, i.e. how well they absorb and emit light, is crucial to realizing these advanced concept devices. We report on InAs quantum dots whose optoelectronic performance has been improved by a Sb treatment prior to capping with GaAs. Significant increase in photoluminescence output is seen with a maximum performance for intermediate Sb spray times. The atomic structure of the Sb-sprayed QDs and the surrounding material matrix was investigated by means of high-resolution transmission electron microscopy (HRTEM) and atom probe tomography (APT). The results reveal the variability of dot shape and size, chemistry complexity and the degree of intermixing between Sb/dots and capping layer. These results can offer insights into the performance boosts observed and how further improvement might be made.R investigations have shown the attraction of using thin films doped with noble metal nanoparticles as recording media. Noble nanoparticles are used because of their strong resistance to frequencies range of optical radiation. As it is well known, the process of recoding is based on melting of nanoparticles into nanospheres without losing matter, which is caused by longitudinal surface plasmon resonance (SPR) induced by laser radiation. Longitudinal SPR is highly sensitive to such geometrical parameters of nanoparticles as aspect ratio and their orientation with respect to polarization of laser radiation. Thus, it is possible to record multiple patterns in one recording layer by using a number of scattered nanorods with different aspect ratio and orientation. As pattern recording is based on melting of nanorods into nanospheres of the same volume under the influence of laser radiation, detailed understanding of this process with respect to nonlinear properties of separated nanorods, as well as their closed-packed array, is the key to construction of new recording media. In this report, we investigate new nonlinear phenomenon: fast and slow laser light under a propagation of pulse with femtosecond duration in the medium with nanorods. We take into account the TPA of laser radiation by nanorods and time-dependence of changing the aspect ratio of nanorods due to their melting because of the laser energy absorption. We also take into account the dependence of the central frequency of the nanorods absorption spectrum from the aspect ratio, detuning between the central frequency of the absorption spectrum and the carrier frequency of the laser pulse, group velocity dispersion and the finite width of both the absorption spectrum and laser pulse spectrum. This phenomenon is very important for process of data storage and data processing using medium with nanoroads.T use of nanoporous membrane in fabrication of biosensorsof high sensitive and specificity for the detection of various analyte is currently an issue of great importance, and its success is often dictated by the size and nature of pore as well as the detection element (the specific ligand) along with choice of target analyte. Here we introduce a polycarbonate trek etched (PCTE) nanoporous membrane having a 5nm gold sputtered porous layer to be used as a selective biorecognition element in aimpedimetricnanoimmunosensor for the label-free detectionof fluorescent Pseudomonasin real soil samples. A simple and rapid method to modify a nanoporous gold surface of membrane through functionalization bythe attachment of thiol group is followed by antigen-antibody complex. Thiolation and antibody attachment has effectively reduced the non-specific bindingof biomolecules and other cells, and permitted successful immobilization of antibodies. The fluorescent Pseudomonas, one of the most used soil-borne plant growth promontory Rhizobacteria, was tested as a model bacteria in this study.A different nanomaterials, gold nanoparticles are especially interesting for biocatalysis because of great affinity of gold to thiols and amino groups, which are present in enzymes. Such interactions may cause changes in a structure of an enzyme and modify its substrate specificity. In literature, there is no information about influence of gold nanoparticles on enzyme stereoselectivity. Therefore systematic studies were performed to verify this phenomenon. Selected enzymes were immobilized on gold nanoparticles using different protocols. Obtained bionanocatalysts were used in a model stereoselective reaction. The influence of bionanocatalysts structure on the stereochemical course of the reaction studied will be discussed.C oxide nanoparticles were prepared hydrothermally at low temperature using water as solvent in microwave oven. The complex was characterized for its size and structure using scanning electron microscopy (SEM), energy dispersive X-ray analysis energy “EDX” and X-ray diffraction “XRD” techniques. The effect of temperature on the morphology and the final products were studied, and the energy dispersive X-ray analysis energy show that this salt is pure and consist of only cadmium and oxygen. The mechanism of the reaction was concluded from collected data.N conjugated polymer thin films represent a promising material for applications such as sensing or organic photovoltaics due to their enhanced interface and semi-conducting properties. While most researchers focus their studies on either elaborated chemistry or time and energy-consuming nano-imprinting methods, we here demonstrate that nanostructured P3HT thin films are easily obtained by using commercially available polymers through self-assembly followed by selected removal of one of the phases. P3HT is among the most widely used conjugated polymers, especially for transistors, sensors and photovoltaic applications. Our simple and cost-effective fabrication process is based on spin-coating of polymerpolymer blends. In order to obtain relatively ordered structures, the compatibility between the two polymers must be given particular attention. For instance, we find that highly incompatible polymers form bilayers rather nanostructured films. With the adequate system, we further investigate the influence of the molecular weights and the relative concentration of the two polymers to control the dimensions of the nanostructures obtained (nanopores and nanoislands). Playing on these parameters, we observe how an increased interface between donor and acceptor molecules in organic solar cells can enhance the device performances. Furthermore, a careful study using angle dependent FTIR and ellipsometry revealed that the conjugated polymer crystallites in the nanostructured films undergo a reorientation at the polymer-polymer interface which is beneficial for an enhanced charge collection within the semi-conducting layer of the solar cells. This low-cost and adaptable method could be applied to a variety of materials to fabricate innovative and original functional devices.E field-induced metal-insulator transition in correlated electron materials has been attracting much attention as not only a mainstream in a development of oxide electronics but also a platform for investigation of condensed-matter physics. In the common motivation, electric field at gate has been used as accumulation and depletion of electric charge carriers to cause drastic change of the transport property because the correlated electronic phases are very sensitive to the number of carriers. However, it is beginning to be understood that the strong electric field induces redox reaction of into or out of oxygen or hydrogen at the interface in oxide channels, especially in applying ion liquid gates. Recently, as a new concept device actively for focusing on the field induced-redox reaction in oxides using water, large modulations of transport and thermopower properties were reported. Water would be a key material to cause strong redox reaction in oxides by an electric field because electrolyzed water separates the strong active agents of H+ and OH/O2ions. In this research, we demonstrate reversible and memristive modulation of transport properties in vanadium dioxide (VO2) nanowires, which is a prototypical correlated electron material, using electric field-induced water electrolysis through air nano-gap in a planer type gate. The device totally works under an ambient air condition at room temperature. Our results offer a newly convenient technique to induce redox reaction and will serve as a powerful tool for examining transport properties on redox effect.T sci‐fi inspired miniaturization of full‐scale robotic manipulation down to the mesoscopic scale regime opens new doors for exploiting the forces of photons for micro‐ and nanobiologic probing, actuation and control. A generic approach for optimizing light‐matter interaction on these scales involves the combination of optimal light‐sculpting with the use of optimized shapes in micro‐ and nano‐robotic structures. Micro‐fabrication processes such as two‐photon photo‐polymerization offer three‐dimensional resolutions for crafting custom‐designed monolithic microstructures that can be equipped with optical trapping handles for convenient opto‐mechanical control using only optical forces. Such microstructures as illustrated above can be effectively handled with simultaneous top and side view on our proprietary BioPhotonics Workstation (BWS) to undertake six degree of freedom optical actuation of tiny 3D‐printed tip structures easily entering the submicron regime. Aided by our international collaborators who fabricated test structures for us, we were able to put our pioneering concept of optically steerable freestanding waveguides coined: wave‐guided optical waveguides to the test using our BWS. We have also proposed using these techniques for generating two photon real time spatially sculpted light for the strongly emerging areas of neurophotonics and optogenetics.We report on position and density control of nitrogen-vacancy (NV) centres created in type Ib diamond using localised exposure from a helium ion microscope and subsequent annealing. Spatial control to <;380 nm has been achieved.T based on transcription factors have the potential to revolutionize medicine, but have had limited medical impact because of delivery problems. In this presentation, we demonstrate that a delivery vehicle, termed DARTs (DNA Assembled Recombinant Transcription factors), can for the first time deliver recombinant transcription factors in vivo, and rescue mice from acute liver failure. DARTs are composed of a double stranded oligonucleotide that contain a transcription factor binding sequence, and have hydrophobic C25 alkyl chains located at their 3’ ends, which are “masked” by acid cleavable galactose residues. DARTs have a unique molecular architecture, which allows them to complex transcription factors, target hepatocytes, disrupt endosomes, and release transcription factors into hepatocytes. We show here that DARTs can deliver the transcription factor Nrf2, to the liver, enhance the transcription of Nrf2 downstream genes, and protect mice from acetaminophen induced liver injury. The DART delivery strategy has tremendous therapeutic potential given the central role of transcription factors in biology and medicine.S technologies are currently in use for computer memory devices. However, there is a need for a universal memory device that has high density, high speed and low power requirements. To this end, various types of magnetic-based technologies with a permanent magnet have been proposed. Recent charge-transfer studies indicate that chiral molecules act as an efficient spin filter. We utilize this effect to achieve a proof of concept for a new type of chiral-based magnetic-based Si-compatible universal memory device without a permanent magnet. More specifically, we use spin-selective charge transfer through a self-assembled monolayer of polyalanine to magnetize a Ni layer. This magnitude of magnetization corresponds to applying an external magnetic field of 0.4 T to the Ni layer. The readout is achieved using low currents. The presented technology has the potential to overcome the limitations of other magnetic-based memory technologies to allow fabricating inexpensive, high-density universal memory-on-chip devices. In the talk author will present nano tool box and show studies of charge transfer, spin transfer and energy transfer in the hybrid layers as well as collective transfer phenomena. These enable the realization of room temperature operating quantum electro optical devices.Electrons in graphene obey Dirac physics which manifests itself through unconventional quantum phenomena, e.g. Klein tunneling - where transmission normal to a potential barrier is close to unity. As a result, graphene systems present unique opportunities for engineering of the electron wavefunction. This would pave the way towards graphene devices and applications that are conceptually entirely new in condensed matter physics and nanoelectronics, such as lateral devices based on quantum interference, or configurable wiring and electron guides. In this presentation the author will focus on two routes for achieving such wavefunction tailoring: Through quantum interference phenomena at lateral interfaces and edges within multi-stacked graphene systems (providing different electron behavior at “hard” and “soft” edges, while interference patterns are controlled by the stacking sequence); and through controlling and modulating the surface potential of the graphene sheet at nanoscale/atomic level via interaction with the substrate and its nanostructures (naturally-occurring or bottom-up engineered). Experimental evidence is collected from scanning probe microscopy studies (Scanning Tunneling, non-contact Atomic Force and Kelvin Probe Microscopies), while theoretical support comes from both full ab-initio and semi-classical calculations. Further, the author will show that inorganic nanostructures provide routes for designing/controlling potentials, electronic superstructures and, ultimately, electron behavioral so in related systems, i.e., carbon nanotubes with encapsulated nanowires. Overall, these examples illustrate generic principles for nanoscale design of properties in graphene-based hybrid systems. - See more at: http://nanotechnology2014.conferenceseries.net/scientific-program.php?day=1&sid=403&date=2014-12-01#sthash.m04QnU8X.dpufP work by our team has demonstrated that calcium phosphosilicate nanoparticles (CPSNPs) are nontoxic candidates for bioimaging and therapeutic drug delivery applications. The pH-dependent solubility profiles of CPSNPs make this class of nanoparticles especially useful for in vitro and in vivo delivery of fluoroprobes as well as chemotherapeutics. CPSNPs that encapsulate the near infra-red fluoroprobe, indocyanine green, have both diagnostic imaging and therapeutic efficacy. These “theranostic” attributes can be exploited to enhance photodynamic therapy (PDT), an alternative modality for cancer treatment. ICG-CPSNPs have enhanced optical imaging properties andfunction as stable photosensitizers for PDT. Data will be presented to demonstrate the theranostic potential of ICG-CPSNPs in multiple models of solid and non-solid tumors. In addition to fluoroprobes and chemotherapeutics, CPSNPs can be formulated to encapsulate molecular-based therapies, such as siRNA. Data will also be presented demonstrating the utility of these non-cationic formulations in in vivo models of cancer.I this talk, the author is going to present two types of ultrasensitive techniques for nano-object sensing. The first one is based on heterogeneously coupled plasmonic waveguides, where giant angular dispersion (AD) as high as 5.4 degree/nm can be achieved. Full-wave vectorial finite difference time domain (FDTD) method was applied which successfully mapped out the modal evolution. It is found that the record high superprism effect originated from the modal competition at the output of the waveguide, where two oppositely swirled optical vortices form. Changing the wavelength of the incident light effectively tunes the relative strength of the vortices, resulting in a controllable beaming effect. Based on the obtained AD, the achievable sensing capability was estimated to be 740 degree/RIU. The second sensing platform was formed by a plasmonic carousel side coupled to a bus waveguide. Due to intra-cavity resonance over the coupling length, giant modal-splitting as large as ∆λ=140 nm can be achieved. Of particular interest, the modal field distributions characterized by two individual resonances form a complementary set in spatial domain, providing two individual channels for sensing the position and polarizability (or the refractive index) of a nano-object simultaneously. Since giant modal splitting of 140 nm has been achieved, ultrasensitive nanoobject detection can be readily realized with a commercially-available, handheld spectrometer with a moderate resolution.T electrochemical erosion of a graphite cathode during the electrolysis of molten lithium chloride salt may be used for the preparation of nano-structured carbon materials. It has been found that the structures and morphologies of these carbon nanomaterials are dependent on those of the graphite cathodes employed and also on the processing parameters such as current density used during the electrolysis process. Tubular and spherical carbon nanostructures can be selectively produced by appropriate control of these parameters.G therapy the transfer of therapeutic DNA into the cells of a patient to treat and potentially cure human disease, has been succeeding in addressing unmet medical needs in increasing number of human clinical trials over the past 5 years. These studies, which have utilized engineered viral carriers in which viral genes have been removed and replaced with therapeutic DNA to treat disease, have established that gene delivery vehicles based on viruses are efficient, safe, and capable of therapeutic gene transfer to numerous target cells and tissues. In particular, nanoscale vehicles or vectors based on the adeno-associated virus (AAV) are highly promising; however, numerous challenges limit their broader utility such as immune responses, physical barriers within complex tissue structures, low delivery efficiency to many cell types, and an inability to target delivery to specific cells. These challenges are not surprising, as nature did not evolve viruses for use as human therapeutics. Rational design has made progress in creating viral variants to address several shortcomings; however, in most situations there is insufficient mechanistic knowledge of underlying virus structure-function relationships to empower rational design with the capacity to engineer a virus. We have been developing directed evolution approaches to address a number of problems with AAV. Directed evolution which emulates the natural evolution process, involves the iterative genetic diversification of a viral genome and functional selection for desired properties. Using this process, we have fundamentally shifted and improved a number of viral delivery properties with implications for clinical gene therapy.


Journal of Molecular Catalysis A-chemical | 2013

In situ stabilization of Pd0-nanoparticles into the nanopores of modified Montmorillonite: Efficient heterogeneous catalysts for Heck and Sonogashira coupling reactions

Bibek Jyoti Borah; Dipak Kumar Dutta


Applied Clay Science | 2011

Synthesis and catalytic activity of Ni°-acid activated montmorillonite nanoparticles

Dipanka Dutta; Bibek Jyoti Borah; Lakshi Saikia; Madan Gopal Pathak; Pinaki Sengupta; Dipak Kumar Dutta


Applied Catalysis A-general | 2014

Efficient Suzuki–Miyaura coupling reaction in water: Stabilized Pdo-Montmorillonite clay composites catalyzed reaction

Bibek Jyoti Borah; Subrat Jyoti Borah; Kokil Saikia; Dipak Kumar Dutta

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Dipak Kumar Dutta

Council of Scientific and Industrial Research

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Podma Pollov Sarmah

North East Institute of Science and Technology

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Biswajit Deb

North East Institute of Science and Technology

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Kokil Saikia

North East Institute of Science and Technology

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Lakshi Saikia

North East Institute of Science and Technology

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Dipanka Dutta

North East Institute of Science and Technology

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Subrat Jyoti Borah

North East Institute of Science and Technology

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Bhaskar Jyoti Sarmah

North East Institute of Science and Technology

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Madan Gopal Pathak

North East Institute of Science and Technology

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Nabin C. Barua

North East Institute of Science and Technology

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