Green synthesis and antimicrobial activity of silver nanoparticles using wild medicinal mushroom Ganoderma applanatum (Pers.) Pat. from Similipal Biosphere Reserve,Odisha, India

In the present study, green synthesis and cost effective approach of silver nanoparticles using wild medicinal mushroom Ganoderma applanatum (Pers.) Pat. from Similipal Biosphere Reserve, Odisha, India is reported. The biosynthesised AgNPs were characterised using UV‐visible spectroscopy, particle analyser and scanning electron microscopy studies. It was found by dynamic light scattering analysis, that the average size and charges of the AgNPs were 133.0 ± 0.361 nm and −6.01 ± 5.30 mV, respectively. Moreover, the Fourier transform infrared study was also conducted to identify the biomolecules or functional groups responsible for the reduction of Ag and stabilisation of the AgNPs. The potential biomedical application with reference to antimicrobial activity of the synthesised AgNPs was investigated against some pathogenic microorganisms viz. Escherichia coli, Bacillus subtilis, Staphylococcus epidermidis, Vibrio cholerae, Staphylococcus aureus and Shigella flexneri.Inspec keywords: antibacterial activity, biomedical materials, nanomedicine, nanofabrication, materials preparation, ultraviolet spectra, visible spectra, scanning electron microscopy, Fourier transform infrared spectra, molecular biophysics, reduction (chemical), biochemistry, microorganisms, silver, nanoparticlesOther keywords: green synthesis, antimicrobial activity, silver nanoparticles, wild medicinal mushroom, Ganoderma applanatum Pat, Similipal Biosphere Reserve, Odisha, UV‐visible spectroscopy, particle analyser, scanning electron microscopy, dynamic light scattering analysis, Fourier transform infrared study, biomolecules, functional groups, silver reduction, AgNP stabilisation, biomedical application, pathogenic microorganisms, Escherichia coli, Bacillus subtilis, Staphylococcus epidermidis, Vibrio cholerae, Staphylococcus aureus, Shigella flexneri, Ag

Abbreviations

AgNPs

‐ Silver Nanoparticles

SPR

‐Surface plasmon resonance

AgNO3

‐Silver nitrate

nm

‐ Nanometer

mm

‐Milimetre

     

Effect of long-term stress and temperature exposure on the fracture toughness of Ti-62222 alloy

Fracture toughness tests were conducted on a Ti-62222 (titanium alloy) sheet being considered for use in high temperature aircraft applications in the as received condition and after exposing the pre-cracked specimens to a sustained stress intensity, K, level between 55 and 60.5 MPa for 200 h at 350°C. It was concluded that the fracture toughness does not degrade as a result of exposure to high temperature and the K levels in this material. The tensile strength in the exposed condition also remained the same as in the as received condition.     

Study of Formulation Variables on Properties of Drug-Gellan Beads by Factorial Design

ABSTRACT

The aim of the present study was to obtain cross-linked calcium-gellan beads containing diclofenac sodium as model drug, using full 3³ factorial design. Drug quantity, pH of cross-linking solution, and speed of agitation were selected as variables for factorial design. The resultant beads were evaluated by scanning electron microscopy (SEM), percent yield, entrapment efficiency, micromeritic properties, swelling and drug release studies. The drug-loaded beads were spherical with size range of 0.85–1.8 mm. Percent yield and entrapment efficiency of various batches were in the range of 86.48–98.28% w/w and 72.52–92.74% w/w, respectively. Calcium-gellan beads containing diclofenac sodium showed pH-dependent swelling and drug release properties. Swelling and drug release were significantly higher in pH 7.4 phosphate buffer than 0.1N HCl. The swelling ratio for beads was up to 22 and 3 for phosphate buffer and 0.1N HCl, respectively. Cumulative diclofenac sodium release from calcium-gellan beads was 12–35% in 0.1N HCl within 2 h, whereas complete drug release was observed within 3–4 h in pH 7.4 phosphate buffer.     

Corrigendum Static Frequency Assignment in Cellular Networks

Abstract. No abstract.     

Effects of SiO<Subscript>2</Subscript> substitution on wettability of laser deposited Ca-P biocoating on Ti-6Al-4V

Silicon (Si) substitution in the crystal structure of calcium phosphate (CaP) ceramics has proved to generate materials with improved bioactivity than their stoichiometric counterpart. In light of this, in the current work, 100 wt% hydroxyapatite (HA) precursor and 25 wt% SiO₂-HA precursors were used to prepare bioactive coatings on Ti-6Al-4V substrates by a laser cladding technique. The effects of SiO₂ on phase constituents, crystallite size, surface roughness, and surface energy of the CaP coatings were studied. Furthermore, on the basis of these results, the effects and roles of SiO₂ substitution in HA were systematically discussed. X-ray diffraction analysis of the coated samples indicated the presence of various phases such as CaTiO₃, Ca₂SiO₄, Ca₃(PO₄)₂, TiO₂ (Anatase), and TiO₂ (Rutile). The addition of SiO₂ in the HA precursor resulted in the refinement of grain size. Confocal laser microscopy characterization of the surface morphology demonstrated an improved surface roughness for samples with 25 wt% SiO₂-HA precursor compared to the samples with 100 wt% HA precursor processed at 125 cm/min laser speed. The addition of SiO₂ in the HA precursor resulted in the highest surface energy, increased hydrophilicity, and improved biomineralization as compared to the control (untreated Ti-6Al-4V) and the sample with 100 wt% HA as precursor. The microstructural evolution observed using a scanning electron microscopy indicated that the addition of SiO₂ in the HA precursor resulted in the presence of reduced cracking across the cross-section of the bioceramic coating.     

Preparation of mixed (Cd,Bi)S composite thin films via surfactant facilitated electrodeposition process and their photoelectrochemical characterization

In the present investigation we explored possibilities of preparing mixed CdS–Bi₂S₃ composite thin films of nanodimensions using a single step surfactant facilitated electrochemical process from aqueous solutions containing different colloidal concentrations of CdS and Bi₂S₃ particles. As deposited composite thin films has been characterized on the basis of SEM, AFM and XRD studies for determination of their surface morphology, surface roughness and grain size. Photoelectrochemical characterization of these composite materials has been carried out on the basis of photopotential, current–voltage (I–V) characteristics under dark and illumination conditions and photoaction spectral studies. Attempt has also been made to estimate the resistance of these composite materials towards their electrochemical corrosion. As prepared mixed (Cd,Bi)S composite semiconductor film exhibits substantial improvement in their photoelectrochemical properties.     

Fuzzy neural computing of coffee and tainted-water data from an electronic nose

In this paper we compare the ability of a fuzzy neural network and a common back-propagation network to classify odour samples that were obtained by an electronic nose employing semiconducting oxide conductometric gas sensors. Two different sample sets have been analysed: first, the aroma of three blends of commercial coffee, and secondly, the headspace of six different tainted-water samples. The two experimental data sets provide an excellent opportunity to test the ability of a fuzzy neural network due to the high level of sensor variability often experienced with this type of sensor. Results are presented on the application of three-layer fuzzy neural networks to electronic nose data. They demonstrate a considerable improvement in performance compared to a common back-propagation network.