Increase In Peak Intensity Research Articles

Disparity of selenourea and selenocystine on methaemoglobinemia in non-diabetics and diabetics.

Organoselenium drugs like selenourea (SeU) and selenocystine (SeC) are found to exhibit several medicinal properties and have reported roles in the field of cancer prevention. However, studies related to their interactions with the major erythroid protein, haemoglobin (HbA) are still in dearth despite being of prime importance. In view of this, it was considered essential to investigate the interaction of these two anticancer drugs with Hb. Both the drugs showed significant changes in absorption spectra of Hb at wavelength of maximum absorption (λmax) 630 nm. SeU itself had no effect on the absorbance value at 630 nm with respect to time even with 400 µM concentration. However, it was rapidly converted to nanoselenium in presence of nitrite and there was an increase in the absorbance rate at 630 nm from 3.39 × 10-3 min-1 (without nitrite) to 8.94 × 10-3 min-1 in presence of nitrite (200 µM) owing to the generation of reactive oxygen species in the medium. Although the generation and increase in peak intensity at 630 nm in Hb generally indicates the formation and rise in the levels of methaemoglobin (metHb), nanoselenium was observed to follow a different path. Instead of causing oxidation of Fe2+ to Fe3+ responsible for metHb formation, nanoselenium was found to interact with the protein part, thereby causing changes in its secondary structure which is reflected in the increasing absorbance at 630 nm. SeC, however, showed a different effect. It was shown to act as a novel agent to reduce nitrite-induced metHb formation in a dose-dependent manner. The efficiency of SeC was again found to be less in diabetic blood samples as compared to the non-diabetic ones. For similar ratio of metHb to SeC (1:8), % reduction of metHb was found to be 27.46 ± 0.82 and 16.1 ± 2.4 for non-diabetic and diabetic samples, respectively, with a two tailed P-value much <0.05 which implies that the data are highly significant.

Laser-plasma proton acceleration with a combined gas-foil target

Laser-plasma proton acceleration was investigated in the target normal sheath acceleration regime with a target composed of a gas layer and a thin foil. The laser’s shape, duration, energy and frequency are modified as it propagates in the gas, altering the laser-solid interaction leading to proton acceleration. The modified properties of the laser were assessed by both numerical simulations and by measurements. The 3D particle-in-cell simulations have shown that a nearly seven-fold increase in peak intensity at the foil plane is possible. In the experiment, maximum proton energies showed high dependence on the energy transmission of the laser through the gas and a lesser dependence on the size and shape of the pulse. At high gas densities, where high intensity was expected, laser energy depletion and pulse distortion suppressed proton energies. At low densities, with the laser focused far behind the foil, self-focusing was observed and the gas showed a positive effect on proton energies. The promising results of this first exploration motivate further study of the target.

Structural and Optical Properties of ZnO and MgZnO Semiconductor Materials at Different Annealing Temperature

Zinc Oxide (ZnO) and Magnesium Zinc Oxide (MgZnO) had received much attention in photoelectronic devices. The current study is performed to investigate the effect of temperature on the structural and optical properties of ZnO and MgZnO with 99.99% purity, deposited on Indium Tin Oxide (ITO) glass using Radio Frequency (RF) magnetron sputtering technique. The Argon flow into the chamber is 10 sccm with a deposition rate of 0.25± 0.1 kA/s, working pressure 4.5 x 10-3 Torr, gas and RF power of 100 watt. Structural analysis using X-Ray Diffraction (XRD) shows that when the temperature increase, the diffraction peak intensity and grain size increase while the deposition time at 30 minutes shows the best intensity. The grain size of ZnO and MgZnO is 0.362 nm and 0.195 nm at 300o C respectively. This shows that the full width half maximum (FWHM) of ZnO is smaller compared to MgZnO. The optical transparency value from UV-Vis spectrophotometer is 78% for ZnO while MgZnO showing 80%. This shows that optical transmittance of MgZnO is slightly higher than ZnO.

SYNTHESIS AND CHARACTERIZATION OF SILVER NANOPARTICLES WITH EPOXY RESIN COMPOSITES

Silver nanoparticles have excellent, electrical and optical properties that make them ideal for optical, biomedical and antimicrobial applications. The main objective of the current study was to change the surface resistance which may increase its absorption. In this research work silver nanoparticles were prepared by co-precipitation method. For this AgNO3 and epoxy resin were mixed in 250 ml deionized water and stirred for half hour. Then Ammonia solution NH4OH was added drop by drop to maintain the PH of solution at (10-11). After filtering the solution the filtrate was dried into oven for 2 hour at the temperature of 1500C. After grinding it was placed into furnace at 10000C for the time span of 5 hours. Three samples were prepared by increasing the concentration of epoxy (0.25g, 0.5g and 0.75g) in the 0.5g of silver. Crystalline structure was examined by using XRD with peak intensity increase of 320 (a.u) at the angle of 270 . The increase in the peak intensity shows that there is deposition of epoxy resin and the texture has been created in same directions. The sample having 0.5 g epoxy and 0.5g Ag examined by FTIR showed sharp peak at 796.72 cm-1 having C-H bending. Also a broad peak appeared 564.88cm-1 which matches to methyl group. Another sample having 0.75g epoxy in 0.5 g silver examined by FTIR showed a sharp peak at 875.79cm-1 which shows C=C bonding. Three broad peaks were obtained at 1424.36cm-1 , 564.88cm-1 and 464.80cm-1 which are due to OH- bonding. The UV-Visible spectroscopy of the sample of epoxy with silver showed that 𝜆max is obtained at 381.98 nm, showing the strong photon absorption of the molecules. It was concluded that epoxy resin composite in silver is a promising approach to enhance the technological applications of silver nanoparticles.

A potent multifunctional Ag/Co-polyvinylpyrrolidone nanocomposite for enhanced detection of Cr(III) from environmental samples and its photocatalytic and antibacterial applications.

Trivalent chromium (Cr(III)) is considered to exhibit hormesis (bi-phasic dose-response) property, where low dose be beneficial and high dose shows toxic effect. The present work describe the development of a bimetallic Ag/Co-polyvinylpyrrolidone nanocomposite (Ag/Co-PVP NPs) probe to detect and quantify Cr(III) ions from aqueous samples. The hydrodynamic size and zeta potential of the particle was determined to be 29±1.3nm and -37.19±2.4 mV respectively. The interaction of Cr(III) with Ag/Co-PVP probe showed drastic change in colour of NPs from dark brown to pale yellow, with corresponding blue shift, tapering width and increased peak intensity. The probe showed high specificity towards Cr(III) among the tested metal ions. A linearity was observed between various dilutions of Cr(III) ions (10 to 50nM) and the absorbance of Ag/Co-PVP NPs at 428nm with R2 value of 0.998. The minimum detectable limit of Cr(III) was calculated to be 0.6nM. The influence of salinity, temperature and pH on detection was studied. The probe was found to detect Cr(III) at acidic pH effectively. Competitive metal ions did not interfere the detection of Cr(III). The water sample collected from Noyyal river was taken to estimate Cr(III) by using the prepared probe to ensure practical applicability. The sample contains 9.3nM of Cr(III) that was cross verified with AAS analysis. Hence, it is understood that the reported probe can be used to detect Cr(III) selectively with high accuracy from aqueous samples. In addition, the particles also exhibited excellent photocatalytic activity under visible light. Ag/Co-PVP nanocomposites exhibited excellent antibacterial activity against both gram +ve (B. subtilis) and gram -ve (E. coli) bacteria.

Structure and mechanical performance for TiAlN films that are grown with a low Al composition

An orthogonal array L9 (34) is used with the grey Taguchi design to optimize the performance of TiAlN films that are grown by direct current magnetron co-sputtering, using a low Al concentration. The structure, mechanical performance and the cutting properties of a coated TiAlN tool for which the films are deposited using various parameters are determined. For the optimal deposition conditions, the (111) diffraction peak intensity increases, which demonstrates an improvement in the crystallinity of the TiAlN films. A TiAlN film coated cutter insert is used for the dry milling of a Cr-Mo alloy steel workpiece and it is shown that the tool flank wear decreases and there are fewer surface defects proved. In the confirmation cutting tests the surface roughness is decreased by 26.08% and the flank wear is 16.15% less. The TiAlN films exhibit good mechanical performance, using grey relational analysis, the improvement rate in hardness H is 14.74%, in friction coefficient is 45.88%, in elastic modulus E is 9.56%, in H/E is 9.09% and in H3/E2 is 25.92%.

Structural, optical and photocatalytic properties of pure and Pd-doped CdS thin films

Pure and palladium (Pd)-doped cadmium sulfide (CdS) thin films were deposited on glass substrate by successive ionic layer adsorption and reaction (SILAR) process with different doping concentrations. X-ray diffraction results confirmed the crystalline and hexagonal phase structure of prepared samples. The increase in the main diffraction peak (002) intensity with increasing Pd concentration revealed the substitution of Pd+2 with Cd+2 in the lattice. The crystallite size increased from 58.32 to 89.71 nm with Pd concentration. Morphology of the thin films shown that the average grain size increases by the agglomeration of nano-grains which become cluster of particles after Pd+2 incorporation. The energy bandgap of the CdS thin films is decreased from 2.44 to 2.37 eV with increasing Pd percentage. Photoluminescence (PL) spectra described that the pure and Pd-doped thin films show a broad PL emission peak associated to the transition of sulfur ion vacancy transfers to the valence band. Moreover, the Pd doping improved the film photostability as well as the photocatalytic degradation of methylene blue (MB).

Influencing factor analysis of the coal matrix compressibility of middle-high rank coals

The pore structure and coal matrix compressibility evolution law and their influencing factors of middle-high rank coals was evaluated based on the combined application of high pressure mercury injection, low-temperature nitrogen gas adsorption and low-temperature carbon dioxide adsorption. The middle-high rank coals are dominated by macropores and micropores, along with lower developed mesopores. The porosity, total pore volume and macropores have an increasing trend with increasing coalification degree. Meanwhile, micropores had gradually become more dominant. Coal matrix compressibility of middle-high rank coals is between 0.55 × 10−10 and 1.42 × 10−10 N/m2, which had significant effects on mesopores, while its influence on macropores rise with the increases of coal rank. There was a negative correlation between coal matrix compressibility and coalification degree, resulting from the increasing peak intensity and elastic modulus during the coalification processes. The polarity of the water molecules tends to reduce the peak strength and elastic modulus of coal. As a result, the deformability becomes more enhanced resulting in increases in coal matrix compressibility. Organic compositions and inorganic minerals have opposite effects on coal matrix compressibility. Inorganic matter can effectively resist coal matrix compressibility, resulting from the higher intensities and elastic features and their roles in supporting cleats and pores while organic matter has the opposite effect. Pore structural features have important influences on coal matrix compressibility. Coal matrix compressibility has a trend of increasing with the increasing in the porosity, total pore volume and macropores or the decreasing in micropores. In the maceral composition, the vitrinite was positively correlated with the peak intensity and elastic modulus of medium rank coal, while inertinite tends to be the opposite. There is a positive correlation between coal matrix compressibility and vitrinite, but the opposite occurs for inertinite, resulting from differences in their mechanical strength and elastic properties.

Structural and Electrochemical Studies of La2O3 Coated LiCoO2 Particles

Nanocrystalline LiCoO2 particles have been surface modified with La2O3 by a simple and cost effective resin coating process. The synthesized pure and La2O3 coated samples were characterized by thermogravimetric analysis / differential scanning calorimetry (TGA/DSC), X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) techniques. XRD studies revealed that the presence of La2O3 coating over LiCoO2 particles did not affect the original layer structure of pure LiCoO2. Also, no extra peak was detected for La2O3 phase. FTIR results confirmed the structural co-ordination of the samples. Also, the shifting and broadening of IR peaks corresponding to LiCoO2 confirmed the presence of IR peaks of La2O3. TEM image showed the formation of interconnected small nanoparticle subunits structure for LiCoO2. TEM image also showed the presence of thin La2O3 layer over LiCoO2 particles. The cyclic voltammetry studies revealed that the La2O3 coated LiCoO2 particles exhibited reversible redox peaks with slight increase in peak intensity and peak area compared to pure LiCoO2. It indicates an improved charge storage capacity of La2O3 coated LiCoO2 sample compared to pure LiCoO2 sample.

Experimental determination of electron attenuation lengths in complex materials by means of epitaxial film growth: Advantages and challenges

Accurate electron attenuation lengths are of critical importance in using electron spectroscopic methods to quantitatively characterize complex materials. Here, the authors show that analysis of core-level and valence-band x-ray photoelectron spectra excited with monochromatic AlKα x-rays from the substrate and measured as a function of film thickness can be used to determine electron attenuation lengths in epitaxial SrTiO3 films on Ge(001). Closely lattice-matched epitaxial heterojunctions are ideal systems for determining attenuation lengths provided the films grow in a layer-by-layer fashion, leading to atomically flat surfaces, and the buried interfaces are atomically abrupt. In principle, either the rate of attenuation of substrate peak intensities or the rate of increase of film peak intensities can be used for this purpose. However, the authors find that structural nonuniformities in the films reduce the accuracy of electron attenuation lengths determined from photoelectrons that originate within the films. A more reliable source of information is found in photoelectrons from the substrate which traverse the film. By using the energy dependence of calculated electron attenuation lengths from the NIST database in combination with Ge 3d core and Ge-derived valence-band intensities, the authors determine electron attenuation length as a function of kinetic energy for SrTiO3.

Improving the Link Availability of an Underwater Wireless Optical Communication System Using Chirped Pulse Compression Technique

The effect of frequency chirping on the link availability of an underwater wireless optical communication (UWOC) system is studied theoretically using a simple and realistic model. It is observed, both theoretically and numerically, that a light pulse can be compressed in temporal axis when propagating in the water medium and can attain the minimum value at a prespecified location by appropriately choosing the initial pulse chirp parameter. The pulse compression takes place due to the interplay between the initial frequency chirp and the group velocity dispersion (GVD) effect. An increase in peak intensity, due to pulse compression, at the prespecified receiver location results in an improvement in the link availability compromised due to both attenuation and turbulence. The link availability is quantified by estimating the fading probability for various cases of initially chirped (+ve, 0, and -ve) Gaussian pulses under the influence of attenuation and turbulence and the results are compared for different scenarios. To have a complete channel description, the effect of particulate scattering on the GVD-induced pulse compression and hence on the fading probability is studied and quantified using the Monte Carlo numerical simulation technique. It is shown that, for the same system and channel parameters, the fading probability of a UWOC system is a few orders of magnitude lower (at a prespecified location) for the case with the negatively chirped pulse than for the cases when the initial pulse chirp is either zero or positive. In addition, the analytical expressions for estimating the focus distance and minimum pulse length, as functions of the channel properties, incident pulse length, and initial chirp parameters, are presented and discussed.

Trans Fatty Acid Analysis of Frying Oil Using ATR-FTIR Spectroscopy: A Study on Indian Traditional Snack Foods

Background: Trans Fatty Acid (TFA) content in oil is an important quality parameter due to its adverse health effect. This study was aimed to examine the TFA content in the frying oil used by street food vendors in India for two traditional snack foods. Methods: Totally, 143 oil samples were collected at different frying times (0, 2, and 4 h) from five different vendors for Samosa and Jalebi. TFA levels of the oil samples were analyzed by Attenuated Total Reflection-Fourier Transform Infrared Spectroscopy (ATRFTIR). Statistical analyses were carried out using SPSS software version 23.0. Results: ATR-FTIR spectra exhibited an increase in peak intensity at 966 cm-1 with different frying time in both frying oil samples, indicating the formation of TFA. The TFA content in oils fried at 4 h was significantly higher than the ones at 0 and 2 intervals. It was found that 3 out of 74 (4%) Samosa fried oils and 12 out of 69 (17.4%) Jalebi fried oils were over the maximum allowed regulatory limit of TFA (5%). Jalebi fried oils had significantly higher TFA content than Samosa fried oils. Conclusion: The increase in frying time decreased the peroxide values and increased saturated fatty acids and TFA values of oils used for both food items. The local vendors and consumers should be educated by national authorities regarding health risk of TFA in street fried snacks.

A photo-capacitive sensor operational from 6 K to 350 K with a solution printable, thermally-robust hexagonal boron nitride (h-BN) dielectric and conductive graphene electrodes

A new exfoliation route is introduced for overcoming the drawback of horn-tip exfoliation by combining it with slow magnetic stirring for hexagonal boron nitride (h-BN) bulk crystals. Inkjet printing of h-BN is then conducted, where various patterns were designed and printed and a change from translucent-to-opaque was observed with increasing printing passes from 1 pass (0.417 µm thickness) to 5 passes (1.964 µm thickness). The increase in the E2g peak intensity in the Raman spectra with the thickness of h-BN printed films is demonstrated, which is attributed to an increase in collective photon number as thickness increases. The effect of temperature on the Raman spectra of printed h-BN patterns is studied and the first-order temperature coefficient χ is derived indicative of the thermal properties of printed h-BN films at elevated temperatures. The red-shift of the E2g peak with temperature arises from the variation in the interplanar vibrational frequency with material expansion due to heating. The χ values of −0.033 cm−1/K and −0.028 cm−1/K for 20 and 30 passes of printed h-BN is suggestive of thermally stable h-BN after annealing. All inkjet-printed graphene/h-BN/graphene capacitors were fabricated and the leakage current density, JLeakage, was measured to be ∼ 72 nA/mm2, while the capacitance density was measured to be ∼ 2.4 µF/cm2. Finally, the influence of temperature, frequency, and light irradiation on the performance of graphene/h-BN-based capacitive structures were explored using capacitance density-voltage measurements. The ratio, Con/Coff, between the capacitance density in the illumination ON state, Con, and in the illumination OFF or dark state, Coff, was also calculated for the graphene/h-BN capacitor fabricated with 30 printing passes. The Con/Coff was ∼ 1.6 at 6 K and ∼ 1.4 at 350 K (measured at 1 kHz frequency), suggesting the potential of this 2D graphene/h-BN heterostructure to serve as a photo-capacitive sensing element for printed electronics applications over a wide thermal regime from 6 K to 350 K.

Luminescence and Scintillation Properties of Dy3+ doped Li6Y(BO3)3 crystal

The orthoborate crystals with a wide optical bandgap allow different rare earth ions as an activator (Ce3+, Dy3+, Eu3+, etc.) to provide efficient luminescence. In the present study, Li6Y(BO3)3 pure and 4 mol% Dy3+ doped single crystals have been grown using the Czochralski method. The light emission of the grown crystals has been characterized by using X-ray luminescence, photoluminescence and thermoluminescence measurements. Intrinsic luminescence property has been observed for pure crystal at 330 nm and the characteristic emission of Dy3+ was observed in doped crystal under X-ray excitation. Photoluminescence study of the doped crystal at low temperature has shown the increased peak intensity with the decrease of temperature from 290 to 10 K. Decay time has been measured at the temperature ranging from 290 to 10 K which consists of three components in each stage. Thermally stimulated luminescence of both pure and 4 mol% Dy3+ doped LYBO crystals have been compared at low temperature from 320 K to 10 K. Scintillation β− counts measured from 300 K to 10 K. The performance of the doped crystal has been tested as a scintillator for thermal neutron imaging.

Satellite-Based Observations of Nonlinear Relationships between Vertical Wind Shear and Intensity Changes during the Life Cycle of Hurricane Joaquin (2015)

Abstract A CIMSS vertical wind shear (VWS-C) dataset based on reprocessed GOES-East atmospheric motion vectors (AMVs) at 15-min intervals has a −0.36 correlation with the CIMSS Satellite Consensus (SATCON) intensity changes at 30-min intervals over the life cycle of Hurricane Joaquin (2015). Correlations are then calculated for four intensity change events including two rapid intensifications (RIs) and two decays, and four intensity change segments immediately before or after these events. During the first RI, the peak intensity increase of 16 kt (6 h)−1 (1 kt ≈ 0.51 m s−1) follows a small VWS-C decrease to a moderate 8 m s−1 value (negative correlation). A 30-h period of continued RI following the first peak RI occurred under moderate magnitude VWS-C (negative correlation), but with a rotation of the VWS-C direction to become more aligned with the southwestward heading of Joaquin. During the second RI, the peak intensity increase of 15 kt (6 h)−1 leads the rapid VWS-C increase (positive correlation), which the horizontal plots of VWS-C vectors demonstrate is related to an upper-tropospheric cyclone to the northeast of Joaquin. A conceptual model of ocean cooling within the anticyclonic track loop is proposed to explain a counterintuitive decreasing intensity when the VWS-C was also decreasing (positive correlation) during the Joaquin track reversal. These alternating negative and positive correlations during the four events and four segments of intensity change demonstrate the nonlinear relationships between the VWS-C and intensity changes during the life cycle of Joaquin that must be understood, analyzed, and modeled to improve tropical cyclone intensity forecasts, and especially RI events.

Near-infrared luminescence spectroscopy in yttrium oxide phosphor activated with Er3+, Li+ and Yb3+ ions for application in photovoltaic systems

Near-infrared emission from phosphors Y2O3 doped with Er3+, Li+ and Yb3+ ions under continuous excitation at 523 nm is reported. The downshifting emissions from 950 to 1090 nm correspond to transitions 4I11/2 → 4I15/2 of Er3+ ions and 2F5/2 → 2F7/2 of Yb3+ ions; the emissions from 1500 to 1600 nm correspond to transitions 4I13/2 → 4I15/2 of Er3+. The role of Yb3+ ions in phosphors of Y2O3 doped with 4 at.% of Er, 2 at.% of Li and 2 at.% of Yb was to enhance the 950–1090 nm emissions around 3.5 times in comparison with Yb3+ free samples, through an energy transfer from the erbium 4I11/2 level to the ytterbium 2F5/2 level. Li+ plays an important role in such energy transfer process. With addition of Li+ an erbium 4I13/2 and ytterbium 2F5/2 level decay time increasing is also observed. A peak intensity increase in XRD patterns of the sample tri-doped revealed that the incorporation of lithium increases the phosphor crystallinity. FT-IR and SIMS studies confirmed that Li+ ions are incorporated into the Y2O3 host. According to the optical and structural properties of these phosphors, they could be used to increase the photon absorption in photovoltaic systems.

Enhanced photoluminescence in CaMoO4:Eu3+ by Mn2+ co-doping

Phosphors doped with rare-earth elements have been extensively employed as white light emitting diodes (wLEDs). Red component is essential in realizing the warm white light efficiently. In this work, we report enhancement in red luminescence of Eu doped phosphor by transition metal doping. Here, a series of Eu3+ doped CaMoO4 and Mn+2/Eu3+ co-doped samples are synthesized successfully by facile auto combustion method. Structural and optical analyses of all samples are studied. UV–Vis analysis of Eu3+ doped CaMoO4 samples ascertains the red-shift in the absorption peak and peak broadening in Mn+2/Eu3+ co-doped CaMoO4. PL study shows an increase in the intensity of emission peaks at 610–630 nm and at 702–711 nm wavelength range up to 4 at % Eu3+ doped CaMoO4, which indicates effective energy transfer from Mo–O charge transfer band to 5D0 level of Eu3+. Luminescence intensity is further increased by Mn+2/Eu3+ co-doping in CaMoO4. For 0.3% at Mn+2 co-doping in CaMoO4:4Eu3+, it is observed that upon 290 nm excitation there is a decrease in the emission broadband around 425 nm–575 nm and increase in intensities of peaks at 612 nm, 615 nm, 654 nm, and 702 nm. Therefore, it is concluded that with proper tuning of Mn+2/Eu3+ doping in CaMoO4, prepared phosphor might have potential application in the fields of lighting and display.

Fabrication and characterization of a novel wound scaffold based on polyurethane added with Channa striatus for wound dressing applications

Wound healing is a complex process and it involves restoration of damaged skin tissues. Several wound dressings comprising naturally made substances are constantly investigated to assist wound healing. In this research, a new wound dressing based on polyurethane (PU) supplemented with essence of Channa striatus (CS) fish oil was made by electrospinning. Morphological study depicted the reduction in fiber diameter than PU with the addition of fish oil (0.552 ± 0.109 μm for 8:1 v/v% and 0.519 ± 0.196 μm 7:2 v/v%) than the pristine PU (0.971 ± 0.205 µm). Fourier transform infrared spectroscopy (FTIR) analysis revealed the presence of fish oil in the composite as identified through increasing peak intensity. Fish oil resulted in the hydrophilic behavior (88 ± 3 (8:1 v/v) and 70 ± 6 (7:2 v/v)) as revealed in the contact angle analysis. Thermal gravimetric analysis (TGA) showed the superior thermal behavior of the wound dressing patch compared to the PU. Atomic force microscopy (AFM) analysis insinuated a decrease in the surface roughness of the pristine polyurethane with the added fish oil. Coagulation assays signified the delay in the blood clotting time portraying its anti-thrombogenic behavior. Hemolytic assay revealed the less toxic nature of the developed nanocomposites with the red blood cells (RBC’s) depicting its safety with blood. Hence, polyurethane nanofibers supplemented with fish oil made them as deserving candidates for wound dressing application.

Green synthesis of silver nanoparticles using leaf and stem bark extract of Pometia pinnata J.R. Forst & G. Forst

Pometia pinnata (Matoa) is widely known for its use in traditional medicines and as fruit sources in Indonesia. Stem bark and leaves of Matoa are the most used parts. Each part contains secondary metabolites, including flavonoids, tannins, triterpenoids, glycosides, and saponins. These compounds could act as reducing agents in the biosynthesis of silver nanoparticles. Our research attempts to compare the efficacy of aqueous extracts of Matoa leaf and stem bark in the biosynthesis of silver nanoparticles. We characterized products of silver nanoparticles using UV-Vis spectrophotometer, transmission electron microscope, and particle size analyzer to compare the biosynthesis between the two parts based on ratios of various concentrations of plant extract to silver nitrate (AgNO3). We found that the solution (extract and AgNO3) became darker as the concentration and reaction time increased. Increasing reaction time also caused an increase in absorption peak intensity due to the reduction process of silver ions. The use of leaf and stem bark for biosynthesis resulted in different shapes and sizes of silver nanoparticles; the use of leaves and stem bark resulted in sphere-shaped silver nanoparticles, whereas the use of aqueous leaf extracts triangle-shaped silver nanoparticles formed.

Ion beam modification of polyaniline: Optical and electrical properties of Cu+ ion implanted thin films

Ion implantation of thin nanometre scale films is believed to facilitate better control of the material modification process in thin films when compared to mainstream chemical and electrochemical methods. In this work emeraldine base polyaniline (PANI) films on Indium Tin Oxide coated Polyethylene Terephthalate (ITO/PET) substrates were implanted with 50 keV Cu+ ions at liquid nitrogen temperature to fluences between 0.5 × 1016 and 5.0 × 1016 ions/cm2 to form Cu-PANI nanocomposite sublayer regions in the films. UV–vis, PL and I-V measurements were used to investigate changes in optical and electrical properties of the films post ion implantation. UV–vis data shows red shifting of the optical band gap as a function of fluence from 3.12 eV down to 1.41 eV. At higher fluences Local Surface Plasmon Resonance (LSPR) effects are observed due to formation of Cu nanoparticles ((NPs) in the PANI matrix. Photoluminescence spectra show an increase in the emission peak intensity with fluence, suggesting a corresponding increase in the number of available charge carriers due to radiation induced carbon clustering. This is corroborated by I-V data, which shows a decrease in the DC resistance of the films as a function of fluence.