Consensus-based data replication protocol for distributed cloud

The Journal of Supercomputing - Data availability ensures efficient data accessibility by the readers anytime and from anywhere. It can be addressed by creating multiple copies of each data file...     

Iodine-loaded poly(silicic acid) gellan nanocomposite mucoadhesive film for antibacterial application

Iodine-loaded poly(silicic acid) gellan nanocomposite film was fabricated and evaluated for antibacterial properties. Poly(silicic acid) nanoparticles were synthesized by condensation of silicic acid under alkaline conditions in the presence of polyvinyl pyrrolidone, phosphate ions, and molecular iodine. The nanoparticles were incorporated into gellan dispersion to prepare gellan nanocomposite film using the solvent casting method. The nanocomposite films were characterized by Fourier transformed infrared spectroscopy, thermogravimetric analysis, and X-ray diffraction studies. The results of characterization studies indicated improved thermal stability and an increase in the degree of crystallinity. The scanning electron micrographs and energy dispersive X-ray spectrum confirmed the uniform dispersion of silica and iodine in the nanocomposite films. The analysis of physical and mechanical properties revealed the enhanced tensile strength, moisture resistance, and higher folding endurance of poly(silicic acid) gellan nanocomposite films as compared to gellan film. Further, the iodine-loaded poly(silicic acid) gellan nanocomposite films showed good antibacterial activity against Staphylococcus aureus and Escherichia coli and effective mucoadhesive strength. The results indicate that iodine-loaded poly(silicic acid) gellan nanocomposite mucoadhesive film can be used for potential antibacterial applications in pharmaceuticals.     

Effect of the polyelectrolyte coating on the photothermal efficiency of gold nanorods and the photothermal induced cancer cell damage

Coating gold nanorods (GNRs) with polyelectrolytes is an effective approach to make them biocompatible for potential use in photothermal treatment (PTT) of cancer. The authors report the effect of coating of the GNRs with polystyrene sulphonate (PSS‐GNRs) and PSS plus poly di‐allyl di‐methyl ammonium chloride (PDDAC‐GNRs) on its photothermal conversion efficiency (PTE), cellular uptake and subsequently the photothermal induced cytotoxicity in human oral cancer cells (NT8e). Coating of GNRs with PSS led to decrease in PTE by ∼30% and further coating it with PDDAC led to its increase to similar level, with respect to as‐ prepared GNRs. The cellular uptake of PDDAC‐GNRs in cancer cells was double than that for PSS‐GNRs. PTT of cancer cells after treatment with 60 pM of either PDDAC‐GNRs or PSS‐GNRs resulted in cytotoxicty of ∼90%. At higher concentration of 120 pM, while PSS‐GNRs showed no further change, for PDDAC‐GNR the photothermal induced cytotoxicity decreased to ∼50%. The broadening of longitudinal surface plasmon peak of PDDAC‐GNRs and appearance of dark clusters in cells under bright‐field microscope suggested intracellular clustering of PDDAC‐GNRs. In conclusion, despite high PTE and cellular uptake of PDDAC‐GNRs, its intracellular clustering (due to acidic pH) adversely affect the PTT of cancer cells.Inspec keywords: polymer electrolytes, gold, nanorods, cancer, nanomedicine, cellular biophysics, toxicology, radiation therapy, polymer filmsOther keywords: polyelectrolyte coating, photothermal efficiency, gold nanorods, photothermal induced cancer cell damage, cancer photothermal treatment, polystyrene sulphonate, poly di‐allyl di‐methyl ammonium chloride, photothermal conversion efficiency, cellular uptake, photothermal‐induced cytotoxicity, human oral cancer cells, dark clusters, bright‐field microscope, PDDAC‐GNR intracellular clustering, acidic pH, intracellular compartment, Au     

Green synthesis of highly stable carbon nanodots and their photocatalytic performance

The present study reports a novel, facile, biosynthesis route for the synthesis of carbon nanodots (CDs) with an approximate quantum yield of 38.5%, using Musk melon extract as a naturally derived‐precursor material. The synthesis of CDs was established by using ultraviolet–visible (UV–vis) spectroscopy, Dynamic light scattering, photoluminescence spectroscopy, X‐ray diffraction, transmission electron microscopy and Fourier transform infrared (FTIR) spectroscopy. The as‐prepared CDs possess an eminent fluorescence under UV–light (λ _ex  = 365 nm). The size range of CDs was found to be in the range of 5–10 nm. The authors further explored the use of such biosynthesised CDs as a photocatalyst material for removal of industrial dye. Degradation of methylene blue dye was performed in a photocatalytic reactor and monitored using UV–vis spectroscopy. The CDs show excellent dye degradation capability of 37.08% in 60 min and reaction rate of 0.0032 min⁻¹. This study shows that synthesised CDs are highly stable in nature, and possess potential application in wastewater treatment.Inspec keywords: carbon, nanostructured materials, nanofabrication, catalysis, photochemistry, ultraviolet spectra, visible spectra, photoluminescence, X‐ray diffraction, transmission electron microscopy, Fourier transform infrared spectra, fluorescence, dyesOther keywords: green synthesis, highly stable CD, photocatalytic performance, biosynthesis route, carbon nanodots, quantum yield, Musk melon extract, naturally derived‐precursor material, ultraviolet‐visible spectroscopy, dynamic light scattering, photoluminescence spectroscopy, X‐ray diffraction, transmission electron microscopy, Fourier transform infrared spectroscopy, FTIR spectroscopy, fluorescence, biosynthesised CD, photocatalyst material, industrial dye, methylene blue dye degradation, photocatalytic reactor, UV‐vis spectroscopy, wastewater treatment, size 5 nm to 10 nm, time 60 min     

Ascorbic acid imprinted polymer-modified graphite electrode: A diagnostic sensor for hypovitaminosis C at ultra trace ascorbic acid level

A new kind of molecularly imprinted polymer-modified graphite electrode was fabricated by “grafting-to” approach, incorporating sol–gel technique, for the detection of acute deficiency in serum ascorbic acid level (SAAL), manifesting hypovitaminosis C. The modified electrode exhibited ascorbic acid (AA) oxidation at less positive potential (0.0 V) than the earlier reported methods, resulting in a limit of detection as low as 6.13 ng mL⁻¹ (RSD = 1.2%, S/N = 3). The diffusion coefficient (1.096 × 10⁻⁵ cm² s⁻¹), rate constant (7.308 s⁻¹), and Gibb's free energy change (−12.59 kJ mol⁻¹) due to analyte adsorption, were also calculated to explore the kinetics of AA oxidation. The proposed sensor was found to enhance sensitivity substantially so as to detect ultra trace level of AA in the presence of other biologically important compounds (dopamine, uric acid, etc.), without any cross interference and matrix complications from biological fluids and pharmaceutical samples.     

Determination of various impurities in synthetic diamond powder

Impurities in industrial synthetic diamond powder samples were analyzed by X-ray diffraction (XRD) and Flame Atomic Absorption Spectrometry (FAAS). Specimen for FAAS is required in solution form. Diamonds are chemically inert to most acids and alkalies. Carbon was removed as CO₂ on heating and estimated gravimetrically. The remaining residue was fused with di-lithium tetraborate and dissolved in nitric acid. Impurities such as Si, Al, Fe, Ca, Mg, W, Na, Co and Ni were then determined by FAAS. Crystalline phases of major impurities were identified by XRD.     

Molecular mobility in a homologous series of amorphous solid glucose oligomers

The molecular mobility of amorphous solid biomaterials influences the stability of dried foods and pharmaceuticals, the viability of seeds and spores, and the desiccation-tolerance of organisms during anhydrobiosis. Current understanding of how structure correlates with molecular mobility in the glassy state is inadequate. We used phosphorescence from vanillin dispersed in amorphous films to study the effect of temperature on molecular mobility in the homologous series of oligosaccharides glucose, maltose, maltotriose, maltotetraose, maltopentaose, maltohexaose, and maltoheptaose. Phosphorescence emission spectra and intensity decays were collected from −10 to as high as 130 °C. Emission peak energy, a measure of the extent of dipolar relaxation around the excited state prior to emission, decreased monotonically with temperature, decreasing more significantly in the glassy state in larger sugars (higher degree of polymerisation). The intensity decays were well fitted with sums of either four (glucose, maltose, maltotriose) or three exponentials (maltotetraose, maltopentaose, maltohexaose, maltoheptaose); fit lifetimes at each temperature varied over nearly two orders of magnitude, suggesting a comparable range in matrix dynamic heterogeneity. The lifetimes decreased monotonically with temperature, while the lifetime amplitudes favoured the long lifetime components at lower and short lifetime components at higher temperatures near T_g. Arrhenius analysis indicated that the rate of non-radiative decay, which reflects coupling of probe vibrations with matrix motions and thus provides an estimate of the matrix molecular mobility, increased with molecular size in the glassy state. Both apparent activation energy and activation entropy increased systematically with temperature in all sugars. These data provide additional evidence that the rate and extent of molecular mobility in glassy state carbohydrates is higher in sugars of greater molecular size (mass) and thus higher glass transition temperature and provides additional insight into the molecular dynamics of the glassy state in carbohydrates.     

Effect of Polysaccharides on the Properties of the Mucoadhesive Poly(Vinyl Alcohol) Multicore–Shell Microparticles

This study discusses about the effect of polysaccharides (agar, gum tragacanth, and guar gum) on the properties of the core (organogel)–shell [poly(vinyl alcohol)] microparticles. The size, swelling, and mucoadhesive properties of the poly(vinyl alcohol) microparticles were altered in the presence of the polysaccharides. Thermal analysis confirmed the presence of organogels within the microparticles. Fourier transform infrared spectroscopy confirmed the presence of the polysaccharides within the microparticles. The microparticles were biocompatible in nature. Drug release indicated that an alteration in the shell composition can be used for altering drug release. Ciprofloxacin-loaded microparticles showed sufficient antimicrobial efficiency.     

Analysis of a SiGe MOSFET at 22nm

The present paper proposes a novel concept which can successfully reduce threshold voltage and increase switching speed of a conventional MOSFET. The proposed structures have been incorporated with a silicon germanium (SiGe) layer as a channel at the 22 nm technology node. Also, extensive analyses have been done to study the effects of replacing conventional polysilicon by graded dopent profile polysilicon, use of a high-k/silicon dioxide stack as a dielectric with graded dopent profile polysilicon and by using a high-k/silicon dioxide stack as a dielectric with a metal gate. Hafnium dioxide is used as a high-k material. Silvaco Athena and Atlas simulators are used for simulation as well as for finding electrical characteristics of the structures. For all the proposed structures two important parameters are studied in detail, threshold voltage and subthreshold slope. Comparing the three structures, it can be seen that using the high-k/silicon dioxide stack as a dielectric with a metal gate yields the best threshold voltage as well as good subthreshold slope which is directly related to the switching behaviour of the device. The required fabrication aspects of the modelled structures are also elaborated in detail.     

Subthreshold Current Modeling of Stacked Dielectric Triple Material Cylindrical Gate All Around (SD-TM-CGAA) Junctionless MOSFET for Low Power Applications

Silicon - Stacked Dielectric Triple Material Cylindrical Gate All Around (SD-TM-CGAA) Junctionless MOSFET has been explored for low power applications. This paper presents an analytical model of...