Fabrication and characterization of biodegradable PHBV/SiO2 nanocomposite for thermo‐mechanical and antibacterial applications in food packaging

In the present study, biogenic silica nanoparticles (bSNPs) were synthesized from groundnut shells, and thoroughly characterized to understand its phase, and microstructure properties. The biopolymer was synthesized from yeast Wickerhamomyces anomalus and identified as Poly (3‐hydroxybutyrate‐co ‐3‐hydroxyvalerate) (PHBV) by GC‐MS and NMR analysis. The bSNPs were reinforced to fabricate PHBV/SiO₂ nanocomposites via solution casting technique. The fabricated PHBV/SiO₂ nanocomposites revealed intercalated hybrid interaction between the bSNPs and PHBV matrix through XRD analysis. PHBV/SiO₂ nanocomposites showed significant improvement in physical, chemical, thermo‐mechanical and biodegradation properties as compared to the bare PHBV. The cell viability study revealed excellent biocompatibility against L929 mouse fibroblast cells. The antibacterial activity of PHBV/SiO₂ nanocomposites was found to be progressively improved upon increasing bSNPs concentration against E. coli and S. aureus.Inspec keywords: X‐ray diffraction, microorganisms, antibacterial activity, nanoparticles, cellular biophysics, nanofabrication, silicon compounds, nanocomposites, filled polymers, nanomedicine, biomedical materials, casting, biodegradable materials, food packaging, food safety, biological NMROther keywords: antibacterial applications, poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate), PHBV matrix, biodegradable PHBV‐SiO₂ nanocomposite, thermomechanical biodegradation properties, biogenic silica nanoparticles, groundnut shells, microstructure properties, biopolymer, yeast Wickerhamomyces anomalus, GC‐MS, NMR analysis, food packaging, intercalated hybrid interaction, XRD analysis, cell viability study, solution casting, SiO₂      

A model for foamed cementing of oil and gas wells

We present a two-dimensional model of the primary cementing process for foamed cement slurries. Foamed cement slurries have a number of claimed advantages, but also have a pressure-dependent density and rheology. The rheology is hard to quantify fully over all ranges of foam quality, which compromises the accuracy of models. The density variation is due to expansion/compression of the gas phase along the well, caused by variations in the static pressure. We show that in the absence of careful control, buoyancy-driven instabilities can result in the annulus, as the foamed slurry expands and the density drops below that of the displaced drilling mud. These instabilities appear to be of a classic porous media/Hele-Shaw cell fingering type, triggered by a threshold unstable density difference. We show that these instabilities are amplified by wellbore eccentricity, occurring lower in the well than in a concentric annulus. Our results question the safe usage of foamed cements in primary cementing.     

Investigation of graphene‐on‐metal substrates for SPR‐based sensor using finite‐difference time domain

In this study, the authors investigated the effects of a single layer graphene as a coating layer on top of metal thin films such as silver, gold, aluminum and copper using finite‐difference time domain method. To enhance the resolution of surface plasmon resonance (SPR) sensor, it is necessary to increase the SPR reflectivity and decrease the full‐width‐half maximum (FWHM) of the SPR curve so that there is minimum uncertainty in the determination of the resonance dip. Numerical data was verified with analytical and experimental data where all the data were in good agreement with resonance angle differing in <10% due to noise present in components such as humidity and temperature. In further analysis, reflectivity and FWHM were compared among four types of metal with various thin film thicknesses where graphene was applied on top of the metal layers, and data was compared against pure conventional metal thin films. A 60 nm‐thick Au thin film results in higher performance with reflectivity of 92.4% and FWHM of 0.88° whereas single layer graphene‐on‐60 nm‐thick Au gave reflectivity of 91.7% and FWHM of 1.32°. However, a graphene‐on‐40 nm‐thick Ag also gave good performance with narrower FWHM of 0.88° and reflection spectra of 89.2%.Inspec keywords: graphene, surface plasmon resonance, finite difference time‐domain analysis, reflectivity, metallic thin films, silver, gold, aluminium, copper, chemical sensors, biological techniquesOther keywords: graphene‐on‐metal substrates, SPR‐based sensor, finite‐difference time domain, metal thin films, surface plasmon resonance sensor, SPR curve, resonance angles, reflectivity, C, Ag, Au, Al, Cu     

基于半透膜的钻井液油气分离检测技术

在钻井过程中,录井对钻井液油气的检测是发现和评价油气层重要手段之一,定量获取油气组分信息是有效评价油气层和油气性质的基础.目前录井气测技术所检测的烃组分通常由电动脱气器获得,受钻井液温度、液面高度和黏度的影响较大,所获得的油气定量信息较少,影响了油气解释与评价的准确性.半透膜对油气具有选择性分离的特性,能直接从钻井液中获取烃类组分,能够为油气解释与评价提供定量的基础信息.通过对半透膜和气体分离技术的研究,制备适合现场油气分离要求的半透膜,并在此基础上研制了半透膜油气分离装置,通过稳定性和灵敏度、耐温和抗冲击性能试验,以及钻井现场的应用,其结果证明了该半透膜钻井液油气分离装置适用于钻井现场的油气检测,扩展了油气检测内容,丰富了油气评价信息.     

Process optimisation for green synthesis of zero‐valent iron nanoparticles using Mentha piperita

The potential of Mentha piperita in the iron nanoparticles (FeNPs) production was evaluated for the first time. The influences of the variables such as incubation time, temperature, and volume ratio of the extract to metal ions on the nanoparticle size were investigated using central composite design. The appearance of SPR bands at 284 nm in UV–Vis spectra of the mixtures verified the nanoparticle formation. Incubating the aqueous extract and metal precursor with 1.5 volume ratio at 50°C for 30 min leads to the formation of the smallest nanoparticles with the narrowest size distribution. At the optimal condition, the nanoparticles were found to be within the range of 35–50 nm. Experimental measurements of the average nanoparticle size were fitted well to the polynomial model satisfactory with R ² of 0.9078. Among all model terms, the linear term of temperature, the quadratic terms of temperature, and mixing volume ratio have the significant effects on the nanoparticle average size. FeNPs produced at the optimal condition were characterised by transmission electron microscopy, thermogravimetry analysis (TGA), and Fourier‐transform infrared spectroscopy. The observed weight loss in the TGA curve confirms the encapsulation of FeNPs by the biomolecules of the extract which were dissociated by heat.Inspec keywords: thermal analysis, iron, X‐ray chemical analysis, particle size, nanoparticles, X‐ray diffraction, scanning electron microscopy, transmission electron microscopy, nanofabrication, ultraviolet spectra, mixtures, Fourier transform infrared spectraOther keywords: incubation time, metal ions, central composite design, SPR bands, UV–Vis spectra, nanoparticle formation, metal precursor, narrowest size distribution, optimal condition, average nanoparticle size, particle size, mixing volume ratio, green synthesis, zero‐valent iron nanoparticles, mentha piperita, transmission electron microscopy, thermogravimetry analysis, Fourier‐transform infrared spectroscopy, TGA curve, biomolecules, temperature 50.0 degC, time 30.0 min, size 35.0 nm to 50.0 nm, Fe     

TiO2 /chondroitin‐4‐sulphate nanocomposite coating on Ti–6Al–4V for implants and prostheses applications

Nano‐titania, chondroitin‐4‐sulphate, and titania/chondroitin‐4‐sulphate nanocomposite were separately deposited on Ti–6Al–4V alloys by repetitive spin coating. Surface characterisation techniques were used to find out the crystalline nature, chemical bonding, surface homogeneity, and elemental composition. Biological studies of nanocomposite‐coated alloys revealed the formation of stable hydroxyapatite (Ca/P = 1.678), superior corrosion resistance, and ∼12 mm zone of inhibition against Staphylococcus sp. However, the cell line studies revealed the better response on polymer‐coated alloy than the uncoated and composite‐coated alloy. It has been found that the nanocomposite coating can synergistically increase the thickness of the pre‐existing passive layer and thereby improve the corrosion resistance of Ti–6Al–4V implant in simulated body fluid. The nanocomposite coatings improved the corrosion resistance of the bare Ti–6Al–4V implant specimens by decreasing the i _corr. The formation of hydroxyapatite on nanocomposite‐coated alloy may have ability to inhibit the release of toxic substance to the adjacent tissues. In addition, the in vitro cell line study confers that the nanocomposite‐coated Ti–6Al–4V induces cell attachment and proliferation, and it eventually help to new bone cell formation than the uncoated one. Overall, this nanocomposite coating can be applied in orthopedic applications for effective biomimic bone regeneration.Inspec keywords: titanium compounds, nanocomposites, titanium alloys, aluminium alloys, vanadium alloys, nanomedicine, biomedical materials, prosthetics, X‐ray diffraction, Fourier transform spectra, infrared spectra, scanning electron microscopy, fluorescence, corrosion resistance, polymer films, calcium compounds, cellular biophysics, boneOther keywords: chondroitin‐4‐sulphate nanocomposite coating, implants, prostheses, nano‐titania, repetitive spin coating, surface characterisation, X‐ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, X‐ray fluorescence, TiAlV, TiO₂ , effective biomimic bone regeneration, orthopaedic applications, bone cell formation, osteoblast cells, cell proliferation, cell attachment, simulated body fluid solution, composite‐coated alloy, polymer‐coated alloy, Staphylococcus sp, corrosion resistance, hydroxyapatite, elemental composition, surface homogeneity, chemical bonding, crystalline nature     

PANI/TiO2 nanocomposite‐based chemiresistive gas sensor for the detection of E. Coli bacteria

In the modern pace of the world, food safety is a major concern. In this work, a simple chemiresistive type gas sensor was fabricated to detect Escherichia Coli (E. coli) bacteria. Polyaniline (PANI) films were deposited on the indium tin oxide substrate by an electrochemical deposition method. TiO₂ nanoparticles were synthesised by facile hydrothermal method. PANI films were modified using hydrothermally prepared TiO₂ nanoparticles by a spin coating method. X‐ray diffraction (XRD), field emission scanning electron microscope (FESEM), Fourier transform infrared (FTIR) and ultraviolet– visible spectrophotometer techniques were used to characterise the PANI/TiO₂ nanocomposites. The peaks obtained in the XRD pattern confirmed the anatase phase of TiO₂ nanoparticles. FESEM analysis showed the nanofibrous structure of the nanocomposite. The FTIR characteristic peaks confirmed the formation of the nanocomposite. The electrical resistance of the sensors was evaluated as a function of the bacterial concentration. The PT2 (TiO₂ coated 5 times on PANI) in comparison with PT1 (TiO₂ coated 3 times on PANI) exhibited good sensitivity to the gas molecules at room temperature. The p‐n junction at PANI/TiO₂ interface improved the physical adsorption of gas molecules. Since no specific antibodies or receptors are used, the sensor has the potential for adaptation to real‐life applications. Thus low cost, real‐time, portable, reusable and sensitive bacteria sensors were fabricated and tested.Inspec keywords: conducting polymers, nanoparticles, nanocomposites, visible spectra, ultraviolet spectra, microorganisms, nanosensors, adsorption, gas sensors, nanofabrication, nanofibres, X‐ray diffraction, titanium compounds, spin coating, field emission scanning electron microscopy, Fourier transform infrared spectra, polymer films, electrodeposition, electrical resistivity, wide band gap semiconductors, biological techniques, nanobiotechnologyOther keywords: simple chemiresistive type gas sensor, polyaniline films, indium tin oxide substrate, electrochemical deposition method, TiO₂ nanoparticles, facile hydrothermal method, PANI films, spin coating method, gas molecules, portable bacteria sensors, reusable bacteria sensors, sensitive bacteria sensors, PANI‐TiO₂ nanocomposite‐based chemiresistive gas sensor, Escherichia Coli bacteria detection, X‐ray diffraction, XRD, field emission scanning electron microscopy, FESEM, Fourier transform infrared spectra, FTIR spectra, ultraviolet‐visible spectra, anatase phase, nanofibrous structure, electrical resistance, bacterial concentration, p‐n junction, physical adsorption, temperature 293.0 K to 298.0 K, TiO₂ , ITO     

Synthesis,characterisation and potential biomedical applications of magnetic core–shell structures: carbon‐, dextran‐, SiO2 ‐ and ZnO‐coated Fe3 O4 nanoparticles

Due to the strong effect of nanoparticles'' size and surface properties on cellular uptake and bio‐distribution, the selection of coating material for magnetic core–shell nanoparticles (CSNPs) is very important. In this study, the effects of four different biocompatible coating materials on the physical properties of Fe₃ O₄ (magnetite) nanoparticles (NPs) for different biomedical applications are investigated and compared. In this regard, magnetite NPs are prepared by a simple co‐precipitation method. Then, CSNPs including Fe₃ O₄ as a core and carbon, dextran, ZnO (zincite) and SiO₂ (silica) as different shells are synthesised using simple one‐ or two‐step methods. A comprehensive study is carried out on the prepared samples using X‐ray diffraction, vibrating sample magnetometry, transmission electron microscopy and Fourier transform infrared spectroscopy analyses. According to the authors'' findings, it is suggested that carbon‐ and dextran‐coated magnetite NPs with high M _s have great potential in the application of magnetic resonance imaging contrast agents. Moreover, silica‐coated magnetite NPs with high coercivity are potentially suitable candidates for hyperthermia and ZnO‐coated Fe₃ O₄ is potentially suitable for photothermal therapy.Inspec keywords: iron compounds, carbon, silicon compounds, zinc compounds, nanomedicine, biomedical materials, nanofabrication, nanoparticles, magnetic particles, coatings, X‐ray diffraction, magnetometry, transmission electron microscopy, Fourier transform spectra, infrared spectra, biomedical MRI, hyperthermia, radiation therapyOther keywords: biomedical applications, magnetic core‐shell nanoparticles, CSNP, cellular uptake, biodistribution, coating material, biocompatible coating materials, co‐precipitation, dextran, zincite, silica, X‐ray diffraction, vibrating sample magnetometry, transmission electron microscopy, Fourier transform infrared spectroscopy, magnetic resonance imaging contrast agents, hyperthermia, photothermal therapy, SiO₂ ‐Fe₃ O₄ , ZnO‐Fe₃ O₄      

Methods of improving efficiency of drilling operations for increasing oil and gas production in Ukraine

The paper reports the main outcome of theoretical research, engineering development, and industrial design efforts to elaborate and implement a complex of technological solutions, equipment, and advanced materials for the purpose of improving efficiency of drilling operations. The authors substantiate a rise in oil and gas production by recovering inactive wells, drilling slant and horizontal boreholes, reducting drilling costs.     

Correlation between structural properties and gas sensing characteristics of SnO2 based gas sensors

Undoped polycrystalline tin oxide sintered in the temperature range 500–1000 °C has been comprehensively characterized with respect to its response to CO, methane and H₂. Results obtained at an operating temperature of 300 °C show that increasing the sintering temperature leads to a gradual increase in CO sensitivity which reaches a maximum after sintering at 800 °C.     

Biologically‐synthesised ZnO/CuO/Ag nanocomposite using propolis extract and coated on the gauze for wound healing applications

Wound healing has long been recognised as a major clinical challenge for which stablishing more effective wound therapies is necessary. The generation of metallic nanocomposites using biological compounds is emerging as a new promising strategy for this purpose. In this study, four metallic nanoparticles (NPs) with propolis extract (Ext) and one without propolis including ZnO/Ext, ZnO/Ag/Ext, ZnO/CuO/Ext, ZnO/Ag/CuO/Ext and ZnO/W were prepared by microwave method and assessed for their wound healing activity on excision experimental model of wounds in rats. The developed nanocomposites have been characterised by physico‐chemical methods such as X‐ray diffraction, scanning electron microscopy, diffuse reflectance UV–vis spectroscopy, Fourier transform infrared spectroscopy, thermogravimetric analysis and Brunauer–Emmett–Teller analyses. The wounded animals treated with the NPs/Ext in five groups for 18 days. Every 6 days, for measuring wound closure rate, three samples of each group were examined for histopathological analysis. The prepared tissue sections were investigated by haematoxylin and Eosin stainings for the formation of epidermis, dermis and muscular and Masson''s trichrome staining for the formation of collagen fibres. These findings toughly support the probability of using this new ZnO/Ag/Ext materials dressing for a wound care performance with significant effect compared to other NPs.Inspec keywords: nanomedicine, X‐ray diffraction, II‐VI semiconductors, visible spectra, ultraviolet spectra, nanocomposites, biomedical materials, proteins, wounds, nanoparticles, scanning electron microscopy, nanofabrication, skin, zinc compounds, silver, antibacterial activity, Fourier transform infrared spectra, copper compounds, molecular biophysicsOther keywords: propolis, wound healing applications, effective wound, metallic nanocomposites, biological compounds, metallic nanoparticles, microwave method, wound healing activity, physico‐chemical methods, Fourier transform infrared spectroscopy, diffuse reflectance UV‐vis spectroscopy, Brunauer‐Emmett‐Teller analyses, wounded animals, wound closure rate, wound care performance, histopathological analysis, scanning electron microscopy, X‐ray diffraction, thermogravimetric analysis, haematoxylin, Eosin stainings, Masson trichrome, epidermis, muscular trichrome, collagen fibres, time 18.0 d, time 6.0 d, ZnO‐CuO‐Ag     

Formulation and characterisation of poly(lactic‐co‐glycolic acid) encapsulated clove oil nanoparticles for dental applications

This study investigated synthesis and characterisation of Nano‐PLGA (poly(lactic‐co‐glycolic acid))/CO (clove‐oil) nanoparticles. The delivery of drug‐loaded nanoparticles to demineralised dentin substrates and their morphological association with a two‐step etch‐and‐rinse adhesive system was studied. The effect of Nano‐PLGA/CO pretreatment on micro‐tensile bond strength of resin‐dentin bonding was scrutinised. This study employed CO‐containing PLGA nanoparticles as a delivery vehicle for sustainable drug release inside dentinal‐tubules for potential dental applications. Emulsion evaporation resulted in uniformly distributed negatively‐charged Nano‐PLGA/Blank and Nano‐PLGA/CO nanoparticles. Scanning electron microscopy/ transmission electron microscopy revealed even spherical nanoparticles with smooth texture. High CO‐loading and encapsulation were achieved. Moreover, controlled CO‐release was evidenced after 15 days, in‐vitro and ex‐vivo. Nanoparticles exhibited low initial toxicity towards human mesenchymal stem cells with excellent antibacterial properties. Nanoparticles penetration inside dentinal‐tubules indicated a close correlation with resin‐tags. Nano‐PLGA/CO pretreatment indicated reduction in short‐term bond strength of resin‐dentin specimens. Nano‐PLGA/CO as model drug‐loaded nanoparticles showed excellent metric and antibacterial properties, low toxicity and sustained CO release. However, the loading of nanoparticles with CO up to ∼10 mg (Nano‐PLGA/CO:10) did not adversely affect short‐term bond strength values. This drug‐delivery strategy could be further expanded to deliver other pulp‐sedative agents and medications with other dental relevance.Inspec keywords: nanoparticles, dentistry, encapsulation, filled polymers, nanofabrication, nanocomposites, nanomedicine, biomedical materials, drug delivery systems, adhesives, tensile strength, biomechanics, resins, proteins, molecular biophysics, biochemistry, emulsions, evaporation, scanning electron microscopy, transmission electron microscopy, texture, cellular biophysics, antibacterial activity, bonds (chemical)Other keywords: poly(lactic‐co‐glycolic acid) encapsulated clove oil nanoparticles, dental applications, drug‐loaded nanoparticle delivery, demineralised dentin substrates, morphological association, two‐step etch‐and‐rinse adhesive system, simulated pulpal pressure, nanoPLGA‐CO pretreatment, microtensile bond strength, resin‐dentin bonded specimens, CO‐containing PLGA nanoparticles, delivery vehicle, sustainable drug release, dentinal‐tubules, potential dental applications, emulsion evaporation, uniformly‐distributed negatively‐charged nanoPLGA‐blank, scanning electron microscopy‐transmission electron microscopy, spherical nanoparticles, smooth texture, high CO‐loading, controlled CO‐release, human mesenchymal stem cells, antibacterial properties, antibiofilm properties, deep nanoparticle penetration, resin‐tags, short‐term bond strength, resin‐dentin specimens, metric properties, antibacterial properties, sustained CO release, pulp‐sedative agents, time 15 d     

In‐vitro and in‐vivo evaluation of chitosan‐based thermosensitive gel containing lorazepam NLCs for the treatment of status epilepticus

The objective of this study was to develop an in‐situ gel containing lorazepam (LZM) loaded nanostructured lipid carriers (NLCs) for direct nose‐to‐brain delivery in order to increase drug therapeutic efficacy in the treatment of epilepsy. Accordingly, LZM loaded NLCs were formulated using emulsification solvent diffusion and evaporation method; then the effects of the formulation variables on different physicochemical characteristics of NLCs were investigated. Thermosensitive in‐situ gels containing LZM‐NLCs were prepared using a combination of chitosan and β‐glycerol phosphate (β‐GP). The anticonvulsant efficacy of LZM‐NLCs‐Gel was then examined using the pentylenetetrazole (PTZ) model. The optimised NLCs were spherical, showing the particle size of 71.70 ± 5.16 nm and the zeta potential of −20.06 ± 2.70 mV. The pH and gelation time for the chitosan solution with 15% (w/v) β‐GP were determined to be 7.12 ± 0.03 and 5.33 ± 0.58 min, respectively. The in‐vivo findings showed that compared with the control group and the group that received LZM‐Gel, the occurrence of PTZ‐induced seizures in the rats was significantly reduced by LZM‐NLCs‐Gel after intranasal administration. These results, therefore, suggested that the LZM‐NLCs‐Gel system could have potential applications for brain targeting through nasal route and might increase LZM therapeutic efficacy in the treatment of epilepsy.Inspec keywords: biomedical materials, nanomedicine, cellular biophysics, electrokinetic effects, drug delivery systems, nanoparticles, brain, pH, drugs, particle size, nanofabrication, medical disorders, polymer gelsOther keywords: evaporation method, β‐glycerol phosphate, β‐GP, optimised NLCs, received LZM‐Gel, LZM therapeutic efficacy, chitosan‐based thermosensitive gel, lorazepam NLCs, nose‐to‐brain delivery, drug therapeutic efficacy, emulsification solvent diffusion, in‐vivo evaluation, in‐vitro evaluation, LZM‐NLC‐gel system, status epilepticus treatment, lorazepam loaded nanostructured lipid carriers, epilepsy treatment, physicochemical characteristics, thermosensitive in‐situ gel, anticonvulsant efficacy, pentylenetetrazole model, particle size, zeta potential, pH, gelation time, chitosan solution, PTZ‐induced seizures, intranasal administration     

Synthesis and studies of bay‐substituted perylene diimide‐based D–A–D‐type SM acceptors for OSC and antimicrobial applications

In this study, the synthesis of a series of bay‐substituted donor–acceptor–donor (D–A–D) type perylene diimide derivatives (3a–3d) has been reported as an acceptor for the small‐molecule‐based organic solar cells (SM‐OSCs) by the Suzuki coupling method. It has been evaluated for the antimicrobial activity against some of the bacteria and fungi. The synthesised SMs were confirmed by Fourier transform‐infrared spectroscopy, nuclear magnetic resonance (NMR), and high resolution mass spectroscopy (HR‐MS). The SMs showed absorption up to 750 nm, which eventually reduced the optical band gap Egopt to  < 2 eV. SMs showed thermal stability up to 400 °C. In the SM‐OSC, the SMs showed a power conversion efficiency of  < 1% with the P3HT donor in bulk hetero‐junction device structure. Additionally, the new SMs showed antimicrobial activity against Gram‐negative bacteria such as Escherichia coli Gram‐positive bacteria such as Bacillus subtilis and antifungal activity against the Candida albicans, and Aspergillus niger. Cytotoxicity studies were carried out against the breast cancer cell lines MCF‐7 using MTT assay method. The results revealed that the SMs was able to inhibit the cancer cells. LD₅₀ s calculated for the SMs 3a–3d were between 200 and 400 µg/ml.Inspec keywords: antibacterial activity, solar cells, microorganisms, Fourier transform spectra, infrared spectra, nuclear magnetic resonance, photonic band gap, thermal stability, cellular biophysics, toxicology, cancer, nanomedicine, organic semiconductors, mass spectroscopy, biomedical materialsOther keywords: bay‐substituted perylene diimide‐based D‐A‐D‐type SM acceptors, donor‐acceptor‐donor type perylene diimide derivatives, small‐molecule‐based organic solar cells, SM‐OSC, Suzuki coupling method, antimicrobial activity, bacteria, fungi, Fourier transform infrared spectroscopy, NMR, HR‐MS, optical band gap, P3HT donor, bulk hetero‐junction device structure, Gram‐negative bacteria, Escherichia coli Gram‐positive bacteria, Bacillus subtilis, antifungal activity, Candida albicans, Aspergillus niger, cytotoxicity, breast cancer cell lines MCF‐7, MTT assay method, cancer cells, wavelength 750 nm, temperature 400 degC     

Synergistic effect of SiO2 on proton conduction and thermal behavior for nanocomposite electrolyte CsH2PO4 fuel cells

Journal of Materials Science: Materials in Electronics - Solid acid composite electrolytes (1?x)CsH2PO4(CDP)/xSiO2 (0?≤?x?≤?0.35) were prepared and...     

First principle study of the self‐switching characteristics of the guanine based single optical molecular switch using carbon nanotube electrodes

The switching property of an optical single molecular switch based on a single DNA molecule guanine with a single walled carbon nanotube electrode has been investigated using density functional theory along with non‐equilibrium Green''s function based first principle approach. The semi‐empirical model of this single bio‐molecular switch has been operated at an ultra‐high 25 THz frequency in mid‐UV range. This single bio‐molecule comprises switching activity upon UV photo‐excitation. The influence of the highest occupied molecular orbital and lowest unoccupied molecular orbital gap and the quantum ballistic transmission into the switching activity are discussed in detail in this study. It has been observed that the maximum ON–OFF ratio, i.e. 327 is obtained at +0.8 V bias voltage. Theoretical results show that current through the twisted form is sufficiently larger than the straightened form, which recommends that this structure has smart prospective application in the future generation switching nanotechnology.Inspec keywords: molecular electronic states, density functional theory, ab initio calculations, DNA, organic compounds, molecular electronics, Green''s function methods, molecular biophysics, single‐wall carbon nanotubes, optical switches, orbital calculationsOther keywords: nonequilibrium Green''s function, semiempirical model, single bio‐molecular switch, UV photo‐excitation, lowest unoccupied molecular orbital gap, first principle study, single optical molecular switch, switching property, optical single molecular switch, single DNA molecule guanine, single walled carbon nanotube electrode, density functional theory, highest occupied molecular orbital gap, switching nanotechnology     

Design and damping characteristics of magneto‐rheological fluid damper for special object

Aiming at the vibration characteristics of a small type steel frame, based on the theory of non‐Newton liquid, from the physical property of the magneto‐rheological fluids, the shear stress model of magneto‐rheological fluids damper is built up, the non‐linear characteristics of the magneto‐rheological damper is described, and the parameters of designed magneto‐rheological damper are obtained. The vibration characteristics of the frame structure is studied using magneto‐rheological damper, the results show that after the magneto‐rheological fluids damper fixed, the vibration response of the frame structure is decreased by 42 % for the first mode, which validates the damping effect of the developed magneto‐rheological damper, which provides the theoretical and experimental proof for the design of magneto‐rheological damper.     

Rapid synthesis of Bi 2 O 3 nano‐needles via ‘green route’ and evaluation of its anti‐fungal activity

Here, the authors report a rapid, simple, and eco‐friendly process for synthesis of Bi₂ O₃ nano‐needles. Dioscorea alata tuber extract was used as both reducing and capping agent for the first time. These nanoparticles were characterised by X‐ray diffraction, field emission scanning electron microscope, and Fourier transform infrared (FTIR) spectrometry, the nano‐structured Bi₂ O₃ needles have an average diameter of 158 nm with the lengths in the range of 1–3 μm. CLSI M27‐A2 standard was followed for evaluation of anti‐fungal activity. Bi₂ O₃ nano‐needles show remarkable activity against Candida albicans. It exhibits four time greater activity than bulk Bi₂ O₃ powder and two time greater activity than itraconazole, which makes it a potent anti‐fungal drug.Inspec keywords: bismuth compounds, nanoparticles, X‐ray diffraction, field emission scanning electron microscopy, Fourier transform infrared spectra, drugs, nanomedicine, biomedical materials, nanofabricationOther keywords: nanoneedles, antifungal activity, nanoparticles, X‐ray diffraction, field emission scanning electron microscope, Fourier transform infrared spectrometry, CLSI M27‐A2 standard, Candida albicans, itraconazole, antifungal drug, Bi₂ O₃