Energy Dispersive X-ray Spectroscopy Studies Research Articles

Fabrication of a Superhydrophobic Al2O3 Surface Using Picosecond Laser Pulses

Ultrashort pulse laser (USPL) machining/structuring is a promising technique to create a micropattern on a material surface with very low distortion to the peripheral area or high precession. Thin sheets of alumina (Al2O3) are micromachined with ultraviolet laser pulses of 6.7 ps, to create a superhydrophobic surface by single-step processing. USPL patterned micropillars and microholes have been fabricated with a range of pulses varying from 100 to 1200 pulses/unit area. The impact of the number of pulses/unit area with respect to the geometry and static contact angle measurements has been studied. The surface is free from cracks, and the melting effect is well-pronounced for the blind microhole structures. An energy dispersive X-ray spectroscopy study revealed a marginal change in the elemental composition of the laser-patterned surface. The results show that the geometry of the laser-machined pattern plays a major role in changing the wetting properties rather than the chemical changes induced on the surface. The micropillars exhibited a consistent superhydrophobic surface with a static contact angle measurement of 150° ± 3°.

Local material composite sintered systems for fluoride removal

AbstractThe article elaborates the development of gravity-based water filtration systems capable of removing fluoride using natural organic material. In this study, the precipitation and dissolution reaction occurring in suspension of hydroxyapatite (HAP) as addition of fluoride were investigated under well-defined condition. This process is set to occur in a quasi-static gravity-based water filter system. This system is a (pond sand, organic material (gaur seed powder, neem, sesame sawdust, and Ayurvedic waste), water, and HAP mixture) composite ceramic. This article illustrates these ceramic material systems manufactured using distinct permutations of pond sand and organic materials. HAP is introduced into the composite mix of pond sand and organic materials to manufacture some of the sintered ceramic filtration material systems tested here. The fluoride removal efficiency of these variant systems is discussed. The energy dispersive X-ray spectroscopy studies of the ceramics provided the mineral content...

Bio-nanogate controlled enzymatic reaction for virus sensing.

The objective of this study was to develop an aptamer-based bifunctional bio-nanogate, which could selectively respond to target molecules, and control enzymatic reaction for electrochemical measurements. It was successfully applied for sensitive, selective, rapid, quantitative, and label-free detection of avian influenza viruses (AIV) H5N1. A nanoporous gold film with pore size of ~20 nm was prepared by a metallic corrosion method, and the purity was checked by energy-dispersive X-ray spectroscopy (EDS) study. To improve the performance of the bio-nanogate biosensor, its main analytical parameters were studied and optimized. We demonstrated that the developed bio-nanogate was capable of controlling enzymatic reaction for AIV H5N1 sensing within 1h with a detection limit of 2(-9)HAU (hemagglutination units). The enzymatic reaction was able to cause significant current change due to the presence of target AIV. A linear relationship was found in the virus titer range of 2(-10)-2(2)HAU. No interference was observed from non-target AIV subtypes such as H1N1, H2N2, H4N8 and H7N2. The developed approach could be adopted for sensing of other viruses.

Polyethylene glycol-assisted growth of Cu2SnS3 promising absorbers for thin film solar cell applications

In this paper, we report, for the first time, the results of the polyethylene glycol- (PEG) assisted preparation and characterization of high-quality and well-crystallized Cu2SnS3 (CTS) thin films obtained using sol–gel spin-coating method and a subsequent annealing in a sulphur atmosphere. Structural, morphological, compositional, electrical and optical investigations were carried out. The X-ray diffraction patterns of the samples proved the polycrystalline nature and preferred crystallization of the films. No peak referring to other binary or ternary phases were detected in the patterns. The intensity of the preferred orientation and crystallite size of the films increased with increasing PEG content. This trend yielded an improvement in photo-transient currents of the PEG-assisted growth of CTS films. The scanning electron microscopy images revealed that the CTS films have continuous, dense and agglomeration-like morphology. Through energy dispersive X-ray spectroscopy studies, it has been deduced that the samples consist of Cu, Sn and S of which atomic percentages were consistent with Cu/Sn and S/metal initial ratios. The agglomerated morphology of the samples has been attributed to increasing PEG content. A remarkable enhancement was observed in photo-transient currents of p-n junction of the produced films along with increasing PEG content. Through resistivity-temperature measurements, three impurity level electrical activation energy values for each film were found. Optical band gap values of the films were estimated via absorbance-wavelength behaviours and decreased with increasing PEG content. It has been revealed that PEG-assisted growth of CTS thin films is a promising way to improve its photovoltaic characteristics.

Immobilization of glucose oxidase on graphene and cobalt phthalocyanine composite and its application for the determination of glucose

We described a simple and facile chemical reduction strategy for the preparation of graphene (GR)-cobalt phthalocyanine (CoPc) composite and explored it for the enzymatic determination of glucose. CoPc is an active mediator and electrocatalysts for the immobilization of GOx and determination of glucose. However, it is not stable on the electrode surface and also suffers from lack of conductivity. Here, we have employed GR as the suitable support to stabilize CoPc through simple chemical reduction method and the resulting composite has been used for the glucose biosensor application. Scanning electron microscopy, X-ray diffraction and Energy-dispersive X-ray spectroscopy studies confirmed the successful formation of composite. Direct electron transfer of glucose oxidase (GOx) was observed with well defined redox peaks at the formal potential of −0.44V. The amount of electroactive GOx (Г) and electron transfer rate constant (ks) were calculated to be 3.77×10−10molcm−2 and 3.57s−1, respectively. The fabricated amperometric biosensor detects glucose in wide linear concentration range from 10μM to 14.8mM with high sensitivity of 5.09μAmM−1cm−2. The sensor offered very low detection limit (LOD) of 1.6μM. In addition, practical feasibility of the sensor has been explored in screen printing carbon electrode with accurate determination of glucose present in human blood serum and urine samples. Furthermore, the sensor exhibited appreciable stability, repeatability and reproducibility results.

Surface morphology and optical properties of PVA/PbS nanoparticles

PVA capped lead sulfide (PbS) nanoparticles were successfully synthesized by the simple wet chemical method. The synthesized product has been characterized by powder X-ray diffraction (XRD), UV–vis spectrophotometry, FTIR spectroscopy, scanning electron microscopy (SEM), transmission electron Microscopy (TEM), energy dispersive X-ray spectroscopy (EDX) and photoluminescence studies. The size of the PVA capped PbS nanoparticles was determined From XRD and it is found that the size of the particles of the order of 42–5nm. FTIR and EDX analyses are used to identify the presence of organic molecules and elements in the synthesized PbS nanoparticles. Significant “blue-shift” from bulk material was observed on the PbS nanoparticles using UV–vis spectra.A 10-fold increase in photoluminescence intensity is reached at 4g PVA addition.

Scanning Electron Microscopy and Energy Dispersive X-ray Spectroscopy Studies on Processed Tooth Graft Material by Vacuum-ultrasonic Acceleration.

Purpose:The current gold standard for clinical jawbone formation involves autogenous bone as a graft material. In addition, demineralized dentin can be an effective graft material. Although demineralized dentin readily induces heterotopic bone formation, conventional decalcification takes three to five days, so, immediate bone grafting after extraction is impossible. This study evaluated the effect of vacuum ultrasonic power on the demineralization and processing of autogenous tooth material and documented the clinical results of rapidly processed autogenous demineralized dentin (ADD) in an alveolar defects patient.Methods:The method involves the demineralization of extracted teeth with detached soft tissues and pulp in 0.6 N HCl for 90 minutes using a heat controlled vacuum-ultrasonic accelerator. The characteristics of processed teeth were evaluated by scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDS). Bone grafting using ADD was performed for narrow ridges augmentation in the mandibular area.Results:The new processing method was completed within two hours regardless of form (powder or block). EDS and SEM uniformly demineralized autotooth biomaterial. After six months, bone remodeling was observed in augmented sites and histological examination showed that ADD particles were well united with new bone. No unusual complications were encountered.Conclusion:This study demonstrates the possibility of preparing autogenous tooth graft materials within two hours, allowing immediate one-day grafting after extraction.

Highly stable and sensitive amperometric sensor for the determination of trace level hydrazine at cross linked pectin stabilized gold nanoparticles decorated graphene nanosheets

Herein, we have described a simple electrochemical method for the deposition of the calcium ions cross linked pectin film (CCLP) along with gold nanoparticles (GNPs) on the graphene (GR) modified glassy carbon electrode (GCE) and applied for the determination of hydrazine. The formation of composite film was confirmed by cyclic voltammetry, scanning electron microscopy, Energy-Dispersive X-ray spectroscopy and X-ray diffraction studies. The GR/CCLP-GNPs/GCE film exhibited significantly enhanced electro catalytic ability towards oxidation of hydrazine. The kinetic parameters such as electron transfer coefficient (α) and diffusion coefficient (Do) for the hydrazine oxidation were determined as 0.46 and 2.91×10−6 cm2 s−1, respectively. Two linear ranges were observed in the amperometric determination of hydrazine: (1) 10–600nM with sensitivity of 47.6 nAnM−1cm−2 and (2) 0.6–197.4μM with sensitivity of 1.786μAμM−1cm−2. The sensor is able to detect trace level of hydrazine in nanomolar range with very low deletion limit (LOD) of 1.6nM. This is the lowest LOD achieved compare to all the reported electrochemical amperometric sensors so far. In addition, the sensor is able to detect hydrazine even in the presence of 500 folds excess quantity of interfering ions present in the water and biological liquid. The practicality of the proposed sensor has been demonstrated in water and urine samples. Other advantages of the sensor are repeatability, reproducibility and stability.

Green synthesis of silver and gold nanoparticles using Zingiber officinale root extract and antibacterial activity of silver nanoparticles against food pathogens.

In the present study, we synthesized silver and gold nanoparticles with a particle size of 10-20nm, using Zingiber officinale root extract as a reducing and capping agent. Chloroauric acid (HAuCl4) and silver nitrate (AgNO3) were mixed with Z. officinale root extract for the production of silver (AgNPs) and gold nanoparticles (AuNPs). The surface plasmon absorbance spectra of AgNPs and AuNPs were observed at 436-531nm, respectively. Optimum nanoparticle production was achieved at pH 8 and 9, 1mM metal ion, a reaction temperature 50°C and reaction time of 150-180min for AgNPs and AuNPs, respectively. An energy-dispersive X-ray spectroscopy (SEM-EDS) study provides proof for the purity of AgNPs and AuNPs. Transmission electron microscopy images show the diameter of well-dispersed AgNPs (10-20nm) and AuNPs (5-20nm). The nanocrystalline phase of Ag and Au with FCC crystal structures have been confirmed by X-ray diffraction analysis. Fourier transform infrared spectroscopy analysis shows the respective peaks for the potential biomolecules in the ginger rhizome extract, which are responsible for the reduction in metal ions and synthesized AgNPs and AuNPs. In addition, the synthesized AgNPs showed a moderate antibacterial activity against bacterial food pathogens.

Influence of atomic oxygen exposure on surface resistivity of silicon doped polyimide affecting spacecraft charging

In the present research work, the vulnerability of silicon doped polyimide by atomic oxygen present in LEO (lower earth orbit) of space was investigated. AO-exposure of a fluence of 5.4 × 1018 atoms cm−2 significantly changed the surface resistivity properties of polyimide which is a prime factor governing spacecraft surface charging problem. This amount of fluence affected surface morphology and eroded the surface thickness as observed by SEM (scanning electron microscopy), laser beam imaging and surface profilometer study. This much exposure also increased the oxygen and silicon content on the surface as observed by XPS (X-ray photoelectron spectroscopy) and EDX (Energy-dispersive X-ray spectroscopy) study.

Reversible in situ precipitation: a flow-through approach for coating macroporous supports with metal hydroxides

In this study we report on the production of metal-hydroxide-coated macroporous polymers (MHCMPs), which mainly involves a polyacrylamide backbone coated with iron–aluminium double hydroxides. The coating process is fast, occurs using relatively mild reagents at room temperature, and can be repeated multiple times, thus making it a very simple and flexible process. Electron microscopy and energy dispersive X-ray spectroscopy studies showed that metal hydroxide coating occurred throughout the polymer backbone. It was shown that the mass of metal hydroxides incorporated in the MHCMPs could be adjusted by varying the initial salt solution concentration or the number of cycles in the process. Under the studied conditions, on a polymer backbone of mass 25 mg, we observed a maximum metal hydroxide mass incorporation of 18 mg for the MHCMPs produced at 6 cycles by using 0.4 M iron and aluminium salt solution. Nitrogen adsorption isotherms indicated that the surface area of the MHCMPs increased linearly with the increase in the mass of metal hydroxides incorporated. The polymer backbone with no mass incorporated showed a BET surface area of 18 m2 g−1 and the MHCMPs with maximum mass incorporation under the studied conditions showed a BET surface area of 63 m2 g−1. MHCMPs with varying mass incorporations were applied for arsenic (As(III)) adsorption and showed a high As(III) removal, indicating that they can serve as potential adsorbents. In addition, MHCMPs incorporated with other metal hydroxides were also produced and characterized to show that this method is applicable for coating these as well.

Electrochemical characterization of Ni-Co and Ni-Co-Fe for oxidation of methyl alcohol fuel with high energetic catalytic surface

Non Pt based metals and alloys as electrode materials for methyl alcohol fuel cells have been investigated with an aim of finding high electrocatalytic surface property for the faster electrode reactions. Electrodes were fabricated by electrodeposition on pure Al foil, from an electrolyte of Ni, Co, Fe salts. The optimum condition of electrodeposition were found out by a series of experiments, varying the chemistry of the electrolyte, pH value, temperature, current and cell potential. Polarization study of the coated Ni-Co or Ni-Co-Fe alloy on pure Al was found to exhibit high exchange current density, indicating an improved electro catalytic surface with faster charge- discharge reactions at anode and cathode and low overvoltage. Electrochemical impedance studies on coated and uncoated surface clearly showed that the polarization resistance and impedance were decreased by Ni-Co or N-Co-Fe coating. X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX) and atomic absorption spectroscopy (AAS) studies confirmed the presence of alloying elements and constituents of the alloy. The morphology of the deposits from scanning electron microscope (SEM) images indicated that the electrode surface was a three dimensional space which increased the effective surface area for the electrode reactions to take place.

Hydrothermal synthesis of wurtzite Zn1−xNixS mesoporous nanospheres: With blue–green emissions and ferromagnetic Curie point above room temperature

Wurtzite Zn1−xNixS (x=0.00, 0.01, 0.02, 0.03, 0.04 and 0.05) mesoporous nanospheres were successfully synthesized via a versatile hydrothermal method with the assistance of ethylenediamine (EN). The as synthesized nanospheres were uniform, mono-dispersed with a spherical shape. Microstructure investigations revealed that these nanospheres were mesoporous clusters of Zn1−xNixS nanoparticles with the size around 5nm. X-ray Diffraction, X-ray photoelectron spectroscopy, and Energy-dispersive X-ray spectroscopy studies confirmed that the Ni ions substituted into ZnS host lattice without altering the crystal structure. The Fourier-transform infrared spectra confirmed the coupling between the EN molecules and ZnS. The absorption edge in the diffuse reflection spectra shifted towards lower wavelength with increasing Ni concentration, indicating an expansion in the band gap energy that is estimated to be in the range of 3.53–3.60eV. The photoluminescence spectra of the doped and un-doped samples contained a broad emission band covering the range of 350–650nm. Room temperature magnetization studies indicated that the undoped ZnS nanospheres yielded only diamagnetism, whereas the doped samples exhibited ferromagnetism that can be attributed to the Ni2+ dopants. The temperature dependence of magnetization revealed that the Zn1−xNixS nanospheres have Curie point above room temperature. The intrinsic ferromagnetism and ferromagnetic Curie point above room temperature promise a great deal of potential applications in spintronic devices for Zn1−xNixS nanospheres.

Toxicological profile of small airway epithelial cells exposed to gold nanoparticles

Gold nanoparticles (AuNPs) have diverse applications in the biomedical industry such as in diagnosis, labeling, delivering and sensing. Despite their prevalent medical use, nanotoxicity induced by AuNPs is still largely unknown. We have previously shown that AuNPs could exert cytotoxic effects on lung fibroblasts. In this study, we investigated the invitro toxicological effects of AuNPs in small airway epithelial cells (SAECs) which are the first cells of contact for inhaled NPs and compared expression of metallothionein (MT), a reactive oxygen species scavenger, in SAECs and lung fibroblasts invitro. Transmission electron microscopy (TEM) and energy-dispersive X-ray (EDX) spectroscopy study revealed cellular uptake of aggregates of AuNPs into the cytoplasm at the ultrastructural level. A significant increase in lipid peroxide as well as substantial DNA damage and cytotoxicity was observed in AuNP-treated cells. For MT expression, AuNPs induced down-regulation of the MT-1X isoform in SAECs, but up-regulation of the MT-1X and MT-2 A isoforms in MRC5 lung fibroblasts. The present study suggests that AuNPs could induce oxidative stress-related cytotoxicity and genotoxicity in SAECs.

Surface Modification of Absorbable Magnesium Stents by Reactive Ion Etching

The surface texture and chemistry of WE43 absorbable magnesium stents (AMS) and tube specimens processed by chemical and reactive ion etching (RIE) were investigated. Tube specimens were produced in three different conditions, namely as- received, chemically etched and plasma etched. The results of scanning electron micros- copy, atomic force microscopy and energy dispersive X-ray spectroscopy studies showed that plasma etching and cleaning reduced surface roughness by 10 % compared to chemical etching alone, and completely removed surface deposits remaining from the chemical etch process. The same combination of chemical and plasma etching processes was employed to produce AMS. Expansion tests demonstrated uniform stent expansion characteristics and confirmed the viability of the device. The results of this study show that RIE is an effective surface modification technique for absorbable magnesium devices.

Study of the Painting Methods of Mural Paintings in Ancient Tombs of Goguryeo Using Scanning Electron Microscope

Disputes on the painting methods of Goguryeo murals can mainly be categorized into whether the murals adapted eastern secco or western fresco; however, the murals have their own unique methods as well. There are different viewpoints among experts on interpreting the painting methods. This study involved the creation of research samples to discover the painting methods under dispute and may help discover the methods based on scanning electron microscopy energy-dispersive X-ray spectroscopy (SEM-EDX) studies. Goguryeo murals introduced pseudo-fresco rather than buon fresco methods. Unlike fresco techniques in the West, Goguryeo painters mixed traditional soft binders and adapted typical secco painting techniques for paintings, borders, and corrections after drying. The disputed issues may be resolved by these techniques, and samples may be produced based on the analyzed data. Therefore, many questions can finally be answered through SEM-EDX elemental mapping.

Synthesis of d-Mannose Capped Silicon Nanoparticles and Their Interactions with MCF-7 Human Breast Cancerous Cells

Silicon nanoparticles (SiNPs) hold prominent interest in various aspects of biomedical applications. For this purpose, surface functionalization of the NPs is essential to stabilize them, target them to specific disease area, and allow them to selectively bind to the cells or the bio-molecules present on the surface of the cells. However, no such functionalization has been explored with Si nanoparticles. Carbohydrates play a critical role in cell recognition. Here, we report the first synthesis of silicon nanoparticles functionalized with carbohydrates. In this study, stable and brightly luminescent d-Mannose (Man) capped SiNPs have been synthesized from amine terminated SiNPs and d-mannopyranoside acid. The surface functionalization is confirmed by Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance spectroscopy (NMR), and energy dispersive X-ray spectroscopy (EDX) studies. The mean diameter of the crystal core is 5.5 nm, as measured by transmission electron microscopy (TEM), while the hydrodynamic diameter obtained by dynamic light scattering (DLS) is 16 nm. The quantum yield (QY) of photoluminescence emission is found to be 11.5%, and the nanoparticles exhibit an exceptional stability over two weeks. The Man-capped SiNPs may prove to be valuable tools for further investigating glycobiological, biomedical, and material science fields. Experiments are carried out using Concanavalin A (ConA) as a target protein in order to prove the hypothesis. When Man functionalized SiNPs are treated with ConA, cross-linked aggregates are formed, as shown in TEM images as well as monitored by photoluminescence spectroscopy (PL). Man functionalized SiNPs can target cancerous cells. Visualization imaging of SiNPs in MCF-7 human breast cancer cells shows the fluorescence is distributed throughout the cytoplasm of these cells.

A multi-spectroscopic approach to the characterization of early glaze opacifiers: Studies on an Achaemenid glazed brick found at Susa, south-western Iran (mid-first millennium BC)

This paper presents the results of micro-Raman spectroscopy, energy dispersive X-ray fluorescence (XRF), and scanning electron microscopy–energy dispersive X-ray spectroscopy (SEM–EDS) studies performed on an Achaemenid glazed brick found at Susa (mid-first millennium BC). The results showed that calcium antimonate (CaSb2O6) and lead antimonate (Pb2Sb2O7) were used as white and yellow opacifiers in the white and orange glazes respectively. Moreover, the mixture of calcium antimonate and lead antimonate were used as opacifier in the green glaze. In addition, green, turquoise, blue, and orange colors were achieved by the dissolution of copper, cobalt, and iron-bearing materials in an alkali glaze. A black glazed line, whose color was obtained by copper and iron oxides, was used to separate the colored glazes. The present paper strongly suggests invasive micro-Raman spectroscopy for the identification of the opacifiers used in the early vitreous materials.

Amperometric biosensor based on Prussian Blue nanoparticle-modified screen-printed electrode for estimation of glucose-6-phosphate

Glucose-6-phosphate (G6P) plays an important role in carbohydrate metabolism of all living organisms. Compared with the conventional analytical methods available for estimation of G6P, the biosensors having relative simplicity, specificity, low cost, and fast response time are a promising alternative. We have reported a G6P biosensor based on screen-printed electrode using Prussian Blue (PB) nanoparticles and enzymes, glucose-6-phosphate dehydrogenase, and glutathione reductase. The PB nanoparticles acted as a mediator and thereby enhanced the rate of electron transfer in a bienzymatic reaction. The Fourier transform infrared spectroscopy and energy-dispersive X-ray spectroscopy study confirmed the formation of PB, whereas atomic force microscopy revealed that PB nanoparticles were approximately 25 to 30nm in diameter. Various optimization studies, such as pH, enzyme, and cofactor loading, were conducted to obtain maximum amperometric responses for G6P measurement. The developed G6P biosensor showed a broad linear response in the range of 0.01 to 1.25mM, with a detection limit of 2.3μM and sensitivity of 63.3μA/mM at a signal-to-noise ratio of 3 within 15s at an applied working potential of −100mV. The proposed G6P biosensor also exhibited good stability and excellent anti-interference ability, and it worked well for serum samples.

Attachment of silver nanoparticles (AgNPs) onto thin-film composite (TFC) membranes through covalent bonding to reduce membrane biofouling

Membrane biofouling has a negative impact on the membrane treatment performance. Silver nanoparticles (AgNPs) are well-known antimicrobial agent. Herein, AgNPs with approximately 15nm in diameter were effectively attached to the surface of polyamide (PA) thin-film composite (TFC) membrane via covalent bonding, with cysteamine as a bridging agent. Scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) and cross-sectional transmission electron microscopy (TEM) studies all showed the immobilization of AgNPs. Compared with the pristine TFC membrane, thiol-terminated membrane (TFC–SH) and AgNPs grafted membrane (TFC-S–AgNPs) both showed a higher water flux with slightly lower salt rejection. At a constant transmenbrane pressure of 300psi, the water permeability of TFC–SH, TFC-S–AgNPs, and control TFC membranes was 70.6±0.5, 69.4±0.3, and 49.8±1.7L/m2h, respectively, while NaCl rejection was 93.4±0.1%, 93.6±0.2%, and 95.9±0.6%, respectively. TFC-S–AgNPs had an improved antibacterial ability to inhibit E. coli growth. The silver leaching from the TFC-S–AgNPs membrane surfaces was minimal, as tested by both batch and flow-through methods. The results successfully demonstrated that AgNPs could be grafted onto TFC via chemical bonding, leading towards the development of an advanced functional TFC membrane with anti-biofouling properties.