Varsha Khare

• Ph.D.
• Professor at Seoul National University

Real-world problems are traditionally viewed through a disciplinary lens at the boundary of the physical, life, mathematical and chemical sciences. The existence of these boundaries in taught classroom courses from a traditional context may be an intellectual barrier in seeking critically important hidden connectivities for problems that may have a...

This study presents a comprehensive analysis of the dimerization interfaces of fly GSTs through sequence alignment. Our investigation revealed GSTE1 as a particularly intriguing target, providing valuable insights into the variations within Delta and Epsilon GST interfaces. The X-ray structure of GSTE1 was determined, unveiling remarkable thermal s...

The photocatalytic competence of brookite relative to polymorphs anatase and rutile has generally been considered structurally and energetically unfavourable for reasons that remain largely unknown and unchallenged. Here, we demonstrate...

About this Research Topic The Convergence Paradigm driving self-assembly at the Synthetic and Biosynthetic Boundary Bio-assemblies are distinguishable from synthetically constructed materials by their programmable properties which is inherent of their ability to adapt to their environment. For example, some biostructures use mechanical stress ene...

Ensuring the safe disposal of waste materials to prevent irreversible environmental damage is a major priority concern of the current century. The alarming rate of consumption of plastic-based packaging materials has steadily increased and plastic accumulation now seemingly contributes to the global carbon footprint substantially adding to greenhou...

Interest in carbon materials has soared immensely, not only as a fundamental building block of life, but because its importance has been critical to the advancement of many diverse fields, from medicine to electrochemistry, which has provided much deeper appreciation of carbon functionality in forming unprecedented structures. Since functional grou...

Metal-organic frameworks (MOFs) are arguably a class of highly tuneable polymer-based materials with wide applicability. The arrangement of chemical components and the bonds they form through specific chemical bond associations are critical determining factors in their functionality. In particular, crystalline porous materials continue to inspire t...

Scale driven convergence at the intersection of biology and chemistry could be strategically important in defining a new era in biomanufacturing of materials requiring greater functional complexity. Broadening the functional capability of biologically derived molecules lies in understanding the mechanisms that are intrinsic to their design. While g...

The process of compartmentalization has unique evolutionary importance in biology by facilitating structural order, through the delivery of self-assembled building blocks which are both intrinsically and materially diverse in nature. For example, bacterial micro-compartments formed under biogenic control comprise of semi-permeable protein shells th...

Rapid advancement in the synthetic chemistry of scalable materials permit direct interaction of complex miniaturized structures with biologically assembled materials on an unprecedented order of scale. With the potential to host and trigger new routes to therapeutic pathways, such interactions may be capable of unlocking new biological mechanisms a...

The process of compartmentalization has unique evolutionary importance in biology by facilitating struc-tural order, through the delivery of self-assembled building blocks which are both intrinsically and material-ly diverse in nature. For example, bacterial micro-compartments formed under biogenic control comprise of semi-permeable protein shells...

Crystallization via an amorphous pathway is often preferred by biologically driven processes enabling living species to better regulate activation energies to crystal formation that are intrinsically linked to shape and size of dynamically evolving morphologies. Templated ordering of 3-dimensional space around amorphous embedded non-equilibrium pha...

Enthalpically driven dopant induced defects generated from the interaction of bulk titanium oxide and structure directed agents composed of charge separated ions have important consequences in directing interfacial energies in organometallic semi-conductors. Such external factors imposed by the chemical environment at contrasting surfaces generated...

Nanocontainers embody a ‘compartmentalised’ structural archetype with the potential to operate on a dimensional scale which can either assimilate or be integrated within bio-driven processes. With expected improvements in sensitive diagnostic assays for early disease detection (e.g. CTCs or circulating tumor cells), this has important implications...

In the era of multi-dimensional digital printing technology, engineering by multilayered ‘top-down’ methodologies are redefining manufacturing processes at multi-scale levels with atomic precision permitting unprecedented freedom to design complex structures at will. This challenges the current perception of conventional machining processes for unc...

Accessibility to new synthetic materials to sub-nanometer levels to quantum scales is not trivial—TiO2 is a case in question. The evolution of some biominerals with equilibrium morphologies stabilized by ligand compartmentalization enabling control over shape and size reveals mechanistic clues to engineer biomimetic approaches. Using the principles...

Understanding the complex world of material growth and tunability has mystified the minds of material scientists and has been met with increasing efforts to close the gap between controllability and applicability. The reality of this journey is frustratingly tortuous but is being eased through better conceptual appreciation of metal crystalline fra...

Visible light-active bismuth oxychloride-reduced graphene oxide (BiOCl-RGO) composite photocatalysts were synthesised using a hydrothermal method at low temperature, and at a low cost. This approach reduced the recombination of electron-hole pairs and thereby provided more efficient photocatalysts. The size of BiOCl structure was controlled by poly...

Formation of magnetite in anaerobic sediments is thought to be enhanced by the activities of iron-reducing bacteria. Geobacter has been implicated as playing a major role, as in culture its cells are often associated with extracellular magnetite grains. We studied the bacterial community associated with magnetite grains in sediment of a freshwater...

Ionic liquid has gained much attention from the research community, due to its eco-friendly properties, including low vapor pressure, non-flammability, thermal stability, and high-friction reduction abilities. In this study, a series of experiments were performed to investigate the characteristics of ionic liquids as lubricants in micro end milling...

Graphitic carbon nitride (g-C3N4) was hybridized with CdS nanoparticles and reduced graphene oxide (RGO) sheets using a facile chemical method, for the application of catalytic photodegradation of Rhodamine B and Congo red dyes under irradiation with UV and visible light. Fourier-transform infrared (FTIR) spectroscopy and X-ray photoemission spectr...

Hybrid nano-materials offer potential scope for an increasing number of novel applications when engineered to deliver usefully functional properties. Recent advancement in the design of new material products that result from interactions among different compositions at the nano and micro scale has led to innovative ways to fabricate and process hyb...

In the present study, the effects of ionic liquids (ILs) on the stability of nanoparticles in several IL compositions were investigated. In this context, we examined the primary role of ILs in the synthesis of metal/metal oxide nanoparticles and their dispersions extensively. However, the focus of the discussion in this communication centers mainly...

Magnetotactic bacteria (MTB) synthesize magnetosomes, which are intracellular vesicles comprising a magnetic particle. A series of magnetosomes arrange themselves in chains to form a magnetic dipole that enables the cell to orient itself along the Earth's magnetic field. MamK, an actin-like homolog of MreB has been identified as a central component...

Correlation function and translation diffusion coefficient expressions of scattered intensity. (DOC)

Concentration dependent elution of over-expressed MamK with increasing imidazole. (a) Sodium dodecyl sulfphate-polyacrylamide gel (12%) electrophoresis of purified histidine-tagged MamK eluted using an imidazole gradient to reduce the co-purification of contaminant proteins binding to the column resin. MamK was eluted with increasing concentrations...

Thermal stability of MamK and determination of the α-helical content. Thermal denaturation of MamK (1 mg/ml) was measured by circular dichroism at 222 nm in polymerisation buffer as a function of temperature. The melting temperature of MamK was 66°C. The insert shows the change in the helical content of MamK as a function of temperature. The fracti...

We report on attempts towards the synthesis of titanium nanoparticles using a wet chemical approach in imidazolium-based ionic liquids (ILs) under reducing conditions. Transmission electron microscopy finds nanoparticles in all cases. UV/Vis spectroscopy confirms the nanoparticulate nature of the precipitate, as in all cases an absorption band betw...

Dispersions of Fe(3)C nanoparticles in several ionic liquids (ILs) have been investigated. The ILs are based on 1-ethyl-3-methylimidazolium [Emim] and 1-butyl-3-methylimidazolium [Bmim] cations. Anions are ethylsulfate [ES], methanesulfonate [MS], trifluoromethylsulfonate (triflate) [TfO], tetrafluoroborate [BF(4)], dicyanamide [N(CN)(2)], and thio...

FeII–III hydroxycarbonate green rust GR(CO32−), FeII4 FeIII2 (OH)12 CO3·3H2O, is oxidized in aqueous solutions with varying reaction kinetics. Rapid oxidation with either H2O2 or dissolved oxygen under neutral and alkaline conditions leads to the formation of ferric oxyhydroxycarbonate GR(CO32−)∗, FeIII6 O12 H8 CO3·3H2O, via a solid-state reaction....

Ionic liquids (ILs) have attracted tremendous interest in the recent past for their potential in many chemical fields. The current report explores the effects of a set of ILs based on the 1-ethyl-3-methyl-imidazolium cation and different anions on the formation of gold nanoparticles. X-Ray diffraction finds face-centered cubic gold in all cases, bu...

Abstract We report on attempts towards the synthesis of titanium nanoparticles using a wet chemical approach in imidazolium-based ionic liquids (ILs) under reducing conditions. Transmission electron microscopy finds nanoparticles in all cases. UV/Vis spectroscopy confirms the nanoparticulate nature of the precipitate, as in all cases an absorption...

Due to increased active surface area and high redox flexibility, the green rust- and ferrihydrite- (FH) coated sands appear promising materials in environmental applications such as reactive filtration processes for the elimination and fixation of pollutants in soils, sediments and contaminated water. Recently, different synthesis routes to prepare...

A major enterprise for scientists worldwide is the search for alternative fuels and molecular hydrogen (H2) is a promising candidate. Its large-scale technical production needs to involve water-oxidation catalysts from inexpensive and abundant materials. Here, a water-oxidizing Co-based catalyst film (CoCF) is investigated. We review and extend our...

FeII-III hydroxycarbonate green rust GR(CO32-), FeII4 FeIII2 (OH)12 CO3 • 3H2O, is oxidized in aqueous solutions with varying reaction kinetics. Rapid oxidation with either H2O2 or dissolved oxygen under neutral and alkaline conditions leads to the formation of ferric oxyhydroxycarbonate GR(CO32-)*, FeIII6 O12 H8 CO3 • 3H2O, via a solid-state react...

In photosynthesis, water is oxidized at a protein-bound Mn(4)Ca complex. Artificial water-oxidation catalysts that are similarly efficient and based on inexpensive and abundant materials are of great interest. Recently, assembly of a catalyst as an amorphous layer on inert cathodes by electrodeposition starting from an aqueous solution of cobalt io...

A comparative study of ferrihydrite and ferric green rust coated sand prepared by three synthesis routes has been outlined in the present contribution. The two minerals displayed inverse properties in terms of quantity of deposited iron for all three methods investigated. For ferric green rust coating, a newly proposed synthesis route named as dry...

The oxidation behaviour of Fe(II)Fe(III) hydroxysalt green rust (GR) compounds was investigated using XPS. Stoichiometric GR(CO32−), i.e. Fe(II)4Fe(III)2(OH)12CO33H2O was prepared by co-precipitating Fe(II) and Fe(III) ions in carbonate-containing solution under an inert atmosphere. Fast oxidation of stoichiometric GR(CO32−) by hydrogen peroxide in...

Glassy Zr–Cu–Ni–Al precursor alloys exhibit quasicrystal forming ability in a narrow concentration range via isothermal heating. The formation of quasicrystals has been explained by various arguments. Often, they are considered as Hume-Rothery phases, atomic size or bond strength dependent structures, or a hybrid structure built from Al2Cu- and MoS...

Zr-based quasicrystalline alloys can store hydrogen up to a content close to the highest value known for crystalline materials, but there are questions regarding their structural stability during hydrogen charging. Hydrogenation of Zr69.5Cu12Ni11Al7.5 quasicrystals was observed to increase the (quasi-)lattice constant, but at higher contents also t...

We report on the direct determination of the hydrogen diffusion constant D in the hydrogen-storage quasicrystalline alloy ZrCuNiAl using the technique of nuclear magnetic resonance diffusion in a static fringe field of a superconducting magnet. The diffusion constant of partially quasicrystalline Zr69.5Cu12Ni11Al7.5 exhibits a significant decrease...

We report on the direct determination of the hydrogen diffusion constant D in the hydrogen-storage quasicrystalline alloy ZrCuNiAl using the technique of nuclear magnetic resonance diffusion in a static fringe field of a superconducting magnet. The diffusion constant of partially quasicrystalline Zr69.5Cu12Ni11Al7.5 exhibits a significant decrease...

The hydrogen diffusion constant D in the hydrogenated quasicrystalline alloy ZrCuNiAl has been determined using the technique of NMR diffusion in a static fringe field of a superconducting magnet. The diffusion constant of partially quasicrystalline Zr69.5Cu12Ni11Al7.5 exhibits a significant decrease with increasing hydrogen-to-metal ratio H/M, owi...

We have investigated Fe substituted versions of the quasicrystalline (qc) alloy corresponding to Al65Cu20(Cr, Fe)15 with special reference to the possible occurrence of various quasicrystalline and related phases. Based on the explorations of various compositions it has been found that alloy compositions Al65Cu20Cr12Fe3 and Al65Cu20Cr9Fe6 exhibit i...

In order to find out the effect of Si on quasicrystalline (QC) and related phases, Si has been substituted in place of Al in Al–Cu–Cr system. In the present investigation, various alloys corresponding to Al65−xCu20Cr15Six (x=1,3,5,7and10) composition have been synthesized and characterized. The investigations reveal that at 1at.% of Si both QC and...

The high number of potential interstitial sites suitable for hydrogen and the favorable hydrogen-metal chemistry make quasicrystalline alloys candidates for hydrogen storage applications. Hydrogen charging was performed electrochemically in a 2:1 glycerin-phosphoric acid electrolyte. The microstructure of quasicrystals in Zr69.5Cu12Ni11Al7.5 was in...

In the present work investigations on the effect of stoichiometric variations on the Occurrence and stabilization of quasicrystalline (qc) and related phases have been carried out. Based on the explorations of several Al-deficient and Al-rich versions of the ideal nominal composition i.e. Al65Cu20Cr15, it has been found that the alloy compositions...

The quasicrystalline (qc) alloy Al65Cu20Cr15, unlike its Ru- and Fe-bearing counterparts like Al65Cu20Ru15 and Al65Cu20Fe15, is a metastable phase. This qc alloy has been shown to possess several structural variants and curious structural characteristics. We have investigated the qc alloy Al65Cu20Cr15 with special reference to the possible occurren...