Editorial
Hisatoshi Kobayashi; Mikael Syväjärvi
Research Article
Manoj Kumar Goshisht
Abstract
Designing nanomaterials for biomedical applications is not a trivial task. Avoidance of the immune system, stability in physiological media, and cell membranes, low toxicity, and optimal bioperformances are critical for the success of the designed nanomaterials. This review focuses on the study of protein-protein ...
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Designing nanomaterials for biomedical applications is not a trivial task. Avoidance of the immune system, stability in physiological media, and cell membranes, low toxicity, and optimal bioperformances are critical for the success of the designed nanomaterials. This review focuses on the study of protein-protein and protein-carbohydrates interactions. Most of the biological functions involving biochemical process are closely controlled by protein-protein interactions. Multi-protein complexes perform several catalytic functions. The review also focuses on the in vitro synthesis of bioconjugated nanoparticles and their biological applications such as antimicrobial agents and drug delivery vehicles. The synthesized nanoparticles act as sensor for such interactions. The in vitro synthesis of Au NPs also helps to understand such interactions with better clarity, which are otherwise elusive in the absence of NPs due to their highly complex nature. Both lysozyme (Lys) / Cytochrome, c (Cyt. c) and lysozyme/zein complexes showed remarkable surface adsorption on NP surfaces. The former system produced pH responsive NPs due to its amphiphilic nature and good antimicrobial properties while the latter system produced pH insensitive NPs due to its hydrophobic nature dominated by zein due to presence of non-polar amino acids such as leucine, alanine and proline. Due to insignificant hemolysis both systems may be used as drug delivery vehicles in systemic circulation. The diethylaminoethyl dextran chloride (DEAE) -protein interactions showed that DEAE-BSA and DEAE-Lys mixtures are amphiphilic whereas DEAE-zein mixture is hydrophobic in nature. All different complexes demonstrate strong surface adsorption on both presynthesized Au NPs as well as in vitro synthesis of Au NPs, which leads to the formation of biofunctional Au NPs best suited for biological applications in systemic circulation. The biological applicability is demonstrated from the hemolysis measurements where both DEAE−BSA as well as DEAE−Lys coated Au NPs do not show any marked hemolysis, thus proving to be the best suited vehicles for drug release in systemic circulation. DEAE−zein coated NPs, on the other hand, showed this behavior only in the DEAE rich region of the mixture, but in the protein rich region hemolysis dominates. Copyright © 2017 VBRI Press.
Research Article
Swati Tapdiya; Ashwani K. Shrivastava; Sarika Singh
Abstract
Manganese substituted Cobalt Ferrite Co1-xMnxFe2O4() nanoparticles were prepared using low temperature chemical co-precipitation method. All the samples were annealed at 900°C for 3 hours. The crystal lattice symmetry and phase purity were performed by X-ray diffraction (XRD). The varying dopent ...
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Manganese substituted Cobalt Ferrite Co1-xMnxFe2O4() nanoparticles were prepared using low temperature chemical co-precipitation method. All the samples were annealed at 900°C for 3 hours. The crystal lattice symmetry and phase purity were performed by X-ray diffraction (XRD). The varying dopent concentration affects the crystalline size, surface morphology and magnetic properties of the cobalt ferrite. The particle sizes are found to be in the range of 29-37 nm. SEM with EDAX examines the morphological and compositional analysis of the nanoparticles. EDAX confirms the presence of Co, Mn, Fe and O. Fourier transform infrared spectroscopy (FTIR) study confirms the formation of spinel ferrite. The saturation magnetization, magnetic remanence and coercive field of CoMn nanoparticles are obtained at room temperature. Saturation magnetization initially increases and then decreases for higher value of dopent, which shows applicability of these materials for recording media and magnetic data storage. Copyright © 2017 VBRI Press.
Research Article
Yogita Y. Deshpande; Subhash S. Pingale
Abstract
π-conjugated organic materials such as carbazoles have attracted much attention because of their applications in electronic devices such as OLED’s, solar cells and sensors. Due to their optoelectronic properties, high charge carrier mobility, suitable band gaps and orbital energies, carbazoles ...
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π-conjugated organic materials such as carbazoles have attracted much attention because of their applications in electronic devices such as OLED’s, solar cells and sensors. Due to their optoelectronic properties, high charge carrier mobility, suitable band gaps and orbital energies, carbazoles have received immense attention to serve as a potent photosensitizer for obtaining high performance in DSSC. The present QSPR study of substituted carbazole and carbazole anion with electron donor (NH2) and acceptor (NO2) substituents at various positions is done by the density functional theory (DFT) calculations at B3LYP/6-31G(d,p) level. The longest maximum absorption wavelengths (λmax) in vacuum as well as in polar (acetonitrile) and non-polar (benzene) solvents are studied by using the time-dependent density functional theory (TD-DFT). For the singly substitution of NH2 (at C3) and NO2 (at C4) groups to the carbazole and its anion, the λmax values are observed to be shifted to the longest wavelength from 290.56 nm to 325.73 and 375.77 nm than the other respective positions. Whereas, the respective λmax values for carbazole-anion are found at 384.28 and 590.53 nm respectively. For disubstituted carbazole with NH2 and NO2 at C3 and C4 positions, the longest λmax shifts to 477.15 nm and for carbazole-anion the longest λmax obtained at C4 (NH2) and C5 (NO2) positions with λmax value 694.61 nm. Similar observations are also found in acetonitrile and benzene solvents. Further, it is observed that as the λmax increases, the HOMO-LUMO energy gap (EHL) value decreases accordingly which can be attributed to intramolecular charge transfer from NH2 to NO2 groups. A very good correlation of λmaxwith EHL is observed with correlation coefficient between 0.91 to 0.95 in vacuum as well as in acetonitrile and benzene solvents. Present study may provide valuable guidelines for the choice of suitable substituent to design carbazole moieties as efficient photosensitizer in DSSC. Copyright © 2017 VBRI Press.
Research Article
Alper Uysal
Abstract
In this experimental study, cutting temperatures and burr forms were investigated during MQL (Minimum Quantity Lubrication) milling of AISI 430 ferritic stainless steel. In the experiments, uncoated and TiN (Titanium Nitride) coated WC (Tungsten Carbide) cutting tools were used and the experiments were ...
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In this experimental study, cutting temperatures and burr forms were investigated during MQL (Minimum Quantity Lubrication) milling of AISI 430 ferritic stainless steel. In the experiments, uncoated and TiN (Titanium Nitride) coated WC (Tungsten Carbide) cutting tools were used and the experiments were performed under dry and MQL conditions. A commercial vegetable cutting fluid was chosen as cutting fluid and MQL flow rates were applied at 20 ml/h and 40 ml/h. Additionally, a nanofluid was prepared by adding nano graphene particles to the vegetable cutting fluid at 0,5%wt. Depending on the experimental results, low cutting temperature and small burr forms could have been obtained in the results of using TiN coated WC cutting tool and applying MQL method. In addition, the minimum cutting temperature and burr form were observed during MQL milling with nanofluid. Copyright © 2017 VBRI Press.
Research Article
Sachin K. Srivastava; Parthasarathi Gangopadhyay; S. Amirthapandian; P. Magudapathy; Shyamala R. Polaki; Binay K. Panigrahi; T. N. Sairam
Abstract
Au nanoparticles onto a silica-glass (SiO2) surface have been formed due to thermal dewetting of Au thin films. Subsequently, high energy Si ion-irradiations on the pristine Au nanoparticles result systematic redshifts of optical responses and concomitant broadening of the optical absorption peaks with ...
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Au nanoparticles onto a silica-glass (SiO2) surface have been formed due to thermal dewetting of Au thin films. Subsequently, high energy Si ion-irradiations on the pristine Au nanoparticles result systematic redshifts of optical responses and concomitant broadening of the optical absorption peaks with the increase of ion doses. Essentially, these phenomena have been explained in the light of ion-beam mixing and transient molten-state diffusion process of Au atoms in the underneath SiO2 substrate. Analysis of high resolution electron microscopy and Rutherford backscattering data have corroborated the ion-beam induced mixing of Au atoms with the silica glass. Copyright © 2017 VBRI Press.
Research Article
Swati Mamgain
Abstract
The structural, optical and electrical aspects of as deposited as well as annealed amorphous hydrogenated silicon nitride(a-SiNx: H) thin films of different stoichiometry, grown on silicon wafer by radio frequency- plasma enhanced chemical vapor deposition (RF-PECVD) are thoroughly investigated. Photoluminescence ...
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The structural, optical and electrical aspects of as deposited as well as annealed amorphous hydrogenated silicon nitride(a-SiNx: H) thin films of different stoichiometry, grown on silicon wafer by radio frequency- plasma enhanced chemical vapor deposition (RF-PECVD) are thoroughly investigated. Photoluminescence (PL) measurement verify that Si rich a-SiNx: H (SRSN) film of refractive index 2.68, gives good PL as compared to near stoichiometric film and support the presence of Silicon quantum dots (Si QDs) embedded in a-SiNx: H matrix. Detailed structural analysis by high resolution transmission electron microscopy (HRTEM) revealed that as deposited SRSN thin film contains amorphous Silicon quantum dots (a-Si QDs) which are grown by phase separation of SRSN film during the synthesis process. These SRSN thin films of different thicknesses have been deposited at the surface of Silicon solar cell as anti-reflection coatings (ARCs). By reflectance measurement, it is observed that the ARC contains a-Si QDs in a-SiNx: H matrix, more effectively minimize the reflection of incident light across the wavelengths ranging from 300 to 800 nm. With a-Si QDs/ a-SiNx: H ARC, we demonstrate an increase in short circuit current density, open circuit voltage and conversion efficiency by 4.34 mA/cm2, 0.01V and 0.21% (absolute) respectively and indicate its utility in improving the performance of Si solar cells. Copyright © 2017 VBRI Press.
Research Article
Bhishma Karki; Jeevan Jyoti Nakarmi; Rhiddi Bir singh; Manish Banerjee
Abstract
The influence of Au doping in ZnO thin films was studied with respect to photoelectrocatalytic degradation of methylene blue (MB). Influence of Au doping concentration onto PEC structural morphological, optical and luminescence properties of the ZnO thin films were thoroughly investigated. The maximum ...
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The influence of Au doping in ZnO thin films was studied with respect to photoelectrocatalytic degradation of methylene blue (MB). Influence of Au doping concentration onto PEC structural morphological, optical and luminescence properties of the ZnO thin films were thoroughly investigated. The maximum value of Isc and Voc for 3 at. % Au:ZnO thin films confirms the optimization of doping percentage. XRD and SEM were used to study the structure and morphology of the films. Films were nanocrystalline and exhibit a hexagonal crystal structure with no additional phases of gold compounds. For degradation of MB, Au:ZnO films were used as photoelectrode, it was observed that due to Au:ZnO 80% degradation of MB occurs in 150 min. Moreover, large area (100 cm2) Au doped ZnO thin films have been prepared on FTO coated glasses (10–15 Ω). Photocorrosion of ZnO electrode was examined by atomic absorption spectroscopy and no zinc was observed in AAS measurement. Copyright © 2017 VBRI Press.
Research Article
Bhawana Joshi; Santanu Ghosh; Pankaj Srivastava
Abstract
In the present work, ZnO thin films deposited by pulsed laser deposition (PLD) technique have been characterized structurally and optically after post-deposition annealing. As-deposited thin films were annealed in the ambient atmosphere for different annealing temperatures of 2000C, 4000C, 6000C and ...
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In the present work, ZnO thin films deposited by pulsed laser deposition (PLD) technique have been characterized structurally and optically after post-deposition annealing. As-deposited thin films were annealed in the ambient atmosphere for different annealing temperatures of 2000C, 4000C, 6000C and 8000C. X-ray diffraction (XRD) technique was used for structure analysis and elucidated that both as-deposited and annealed films were of good structural quality and highly oriented towards c-axis. UV-Vis spectrophotometer was used to study the transmittance and optical band gap of as-deposited and annealed films. Photoluminescence (PL) technique was used to investigate the photoluminescent properties of all the films. It was found that ZnO thin films were highly transparent in nature and showed two emissions in PL spectra. One was attributed to near band edge (NBE) emission and the other was the broad deep-level (DL) emission. There was a significant change in the photoluminescent properties of the films and it was observed that the intensity of the DL emission increased significantly with the increase in the annealing temperature. The change in DL emission is attributed to the change in defect states inside the band gap of the annealed films. From the present work, it is inferred that the properties of the ZnO films can be tuned by post-deposition annealing for various applications such as optical and optoelectronic devices. Copyright © 2017 VBRI Press.
Research Article
Umaru Ahmadu; Abdulwaliyu B. Usman; Auwal M. Muhammad; Oyeleke I. Olarinoye; Moses Agida
Abstract
Co-doped barium calcium stannate titanate (Ba0.88Ca0.12Ti0.975Sn0.025O3) ceramics, synthesized via solid state reaction and sintered at 1100 °C/3 h. The ceramics were irradiated with thermal neutrons of up to 1.4 × 1010 n/cm2 using a5 Ci Am-Be source having an average flux of 2.7 × 104 ...
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Co-doped barium calcium stannate titanate (Ba0.88Ca0.12Ti0.975Sn0.025O3) ceramics, synthesized via solid state reaction and sintered at 1100 °C/3 h. The ceramics were irradiated with thermal neutrons of up to 1.4 × 1010 n/cm2 using a5 Ci Am-Be source having an average flux of 2.7 × 104 n/cm2.s. Structural analysis of the ceramics indicate a majorly polycrystalline material with a minor secondary phase. The 2θ positions were observed to shift slightly to higher angles and the microstrain remained constant with increase in fluence. The average crystallite size is ∼ 38 nm with anisotropy in lattice expansion observed. Rod-like grains, porous regions and agglomerations were observed in all the specimens. There was general increase in grain size with increase in fluence and the average grain size is∼1 μm. Chemical analysis indicates slight deviation from nominal ones for some irradiated samples. It is concluded that the structural and microstructural changes observed would not affect the performance of the devices based on this material when used in radiation environments of neutrons as the maximum fluence has not exceeded the order of magnitude of threshold for radiation damage. Copyright © 2017 VBRI Press.
Research Article
Nagendra Vara Prasad M; Jeevan Kumar R; Munikrishna Reddy Y
Abstract
In the present work, Ag2O films are deposited at room temperature using DCMS (Magnetron Sputtering) method with the variation of pressure of O2 during the development of film. The pressure of O2 in the DCMS unit chamber is arranged between 2X10-2 and 6X10-2 Pa. Transmission and absorption spectrum are ...
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In the present work, Ag2O films are deposited at room temperature using DCMS (Magnetron Sputtering) method with the variation of pressure of O2 during the development of film. The pressure of O2 in the DCMS unit chamber is arranged between 2X10-2 and 6X10-2 Pa. Transmission and absorption spectrum are recorded to assess the impact of increasing thickness on certain optical parameters such as indirect band gap, direct band gap, dielectric constant etc. As O2 pressure is varies between 2X10-2 Pa and 6X10-2 Pa, optical energy band gap shows a decreasing trend between 1.041 eV and 0.942 eV. It is also observed that the absorption transmittance of the deposited films increases with the increase of thickness of the film. This way, the study reveals that all the parameters are affected by varying pressure of O2. The effective useful of theseO2-rich films is also discussed keeping in view the increasing importance of the modern technological applications such as photovoltaic cell fabrication. Thus, this technique can also be applied to produce films using other metal oxides. Copyright © 2017 VBRI Press.
Research Article
Susai Rajendran; R Joseph Rathish; S Santhana Prabha
Abstract
Self-assembling molecules form protective layers on metal surfaces Self assembled nanofilms of adipic acid, N-cetyl-N,N,N-trimethyl ammonium bromide, Tween- 60, Sodium dodecyl sulphate and an aqueous extract of banana peel have been formed on the surface of carbon steel ...
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Self-assembling molecules form protective layers on metal surfaces Self assembled nanofilms of adipic acid, N-cetyl-N,N,N-trimethyl ammonium bromide, Tween- 60, Sodium dodecyl sulphate and an aqueous extract of banana peel have been formed on the surface of carbon steel by the immersion method. The formation of the nanofilms has been confirmed by Fourier Transform Infrared spectral study and Atomic Force Microscopy Study. The corrosion inhibitive nature of the protective film has been estimated by the classical weight loss method and electrochemical study such as polarization study. The hydrophobic nature of the protective film has been investigated by measurement of contact angles of the protective films. The hydrophobic surfaces may find application in various exciting fields such as corrosion protection, raincoats, water proof surfaces and biomaterials. Copyright © 2017 VBRI Press.
Research Article
Uma Narang; Kumar K. Yadav; Soumee Bhattacharya; S.M.S. Chauhan
Abstract
The selected porphyrin acids such as 5-(4'-carboxyphenyl)-10,15,20-triphenylporphyrin, 5-(4'-carboxyphenyl)-10,15,20-tris-(4''-chlorophenyl)porphyrin, 5-(4'-carboxyphenyl)-10,15,20-tris-(4''-tertbutylphenyl)porphyrin and 5-(4'-carboxyphenyl)-10,15,20-(4''-pyridyl)porphyrin have been synthesised by reaction ...
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The selected porphyrin acids such as 5-(4'-carboxyphenyl)-10,15,20-triphenylporphyrin, 5-(4'-carboxyphenyl)-10,15,20-tris-(4''-chlorophenyl)porphyrin, 5-(4'-carboxyphenyl)-10,15,20-tris-(4''-tertbutylphenyl)porphyrin and 5-(4'-carboxyphenyl)-10,15,20-(4''-pyridyl)porphyrin have been synthesised by reaction of two aldehydes with pyrrole in propionic acid.The coupling of 5-(4'-carboxyphenyl)-10,15,20-triarylporphyrins with pentan-1,5-diol in presence of EDC and DMAP give unsymmetrical bisporphyrins, which were metallated with zinc acetate to give different porphyrin tweezers. The singlet oxygen efficiency of porphyrin tweezers as photosensitizers have been quantified by monitoring the transformation of1,3-diphenylisobenzofuran (DPBF) to 1,2-dibenzoylbenzene by UV-visible spectroscopy. The quantum yield of formation of singlet oxygen for different porphyrin tweezers have been examined. The electron withdrawing group containing porphyrin tweezer is a better photosensitizer than electron donating group in generation of singlet oxygen. Copyright © 2017 VBRI Press.
