Antibacterial ciprofloxacin HCl incorporated polyurethane composite nanofibers via electrospinning for biomedical applications

We report on the preparation and characterization of polyurethane (PU) composite nanofibers by electrospinning. Two different approaches were adopted to obtain the PU composite nanofibers. In the first approach, a homogeneous solution of 10 wt% PU containing ciprofloxacin HCl (CipHCl) drug was electrospun to obtain PU/Drug composite nanofibers. And in the second approach, the PU with ciprofloxacin HCl drug and ceramic hydroxyapatite (HA) particles were electrospun to obtain the PU/Drug and PU/Drug/HA composite nanofibers. The surface morphology, structure, bonding configuration, optical and thermal properties of the resultant products were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and UV–vis spectroscopy. The antibacterial activity was tested against common food borne pathogenic bacteria, namely, Staphylococcus aureus, Escherichia coli by the minimum inhibitory concentration (MIC) method. Our result results demonstrate that these composite nanofibers possess superior characteristics which can utilized for variety of applications.     

Preparation of nylon-6/chitosan composites by nanospider technology and their use as candidate for antibacterial agents

Electrospun nylon-6/chitosan (nylon-6/Ch) nanofibers were prepared by nanospider technology. Quaternary ammonium salts as antibacterial agent were immobilized onto electrospun nylon-6/Ch nanofibers via surface modification by soaking the mat in aqueous solution of glycidyltrimethylammonium chloride (GTMAC) at room temperature overnight to give nylon-6/N-[(2-hydroxy-3-trimethylammonium)propyl] chitosan chloride (nylon-6/HTCC). The morphological, structural and thermal properties of the nylon-6/ch nanofibers were studied by field-emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), Fourier transform-infrared (FT-IR) spectroscopy, and thermogravimetric analysis (TGA). Biological screening has demonstrated the antibacterial activity of the electrospun nanofibers against Gram negative bacteria, Escherichia coli 35218, and Pseudomonas aeruginosa and Gram positive bacteria, Staphylococcus aureus 24213 among the tested microbes. Thus, the study ascertains the value of the use of electrospun nanofibers, which could be of considerable interest to the development of new antibacterial materials for biomedical applications.     

A comparative study of electrocatalytic performance of metal molybdates for the water oxidation

Binary mixed oxides of molybdenum and a metal of the first-row transition metals with compositional formulae, MMoO₄ (where M = Cr, Fe, Mn, Co, Ni, Cu or Zn), were prepared by a microwave-assisted co-precipitation method and their electrocatalytic activities have been investigated for oxygen evolution reaction (OER) in 1 M KOH. Materials were characterized for structural and electrocatalytic surface properties using FT-IR, XRD, TEM, BET, XPS, cyclic voltammetry (CV) and anodic Tafel polarization techniques. The crystallite size of oxides ranged between ～17 and ～41 nm. For electrochemical studies, oxides obtained in powders form were produced in the thin-film form on the pretreated glassy carbon (GC) support. It has been observed that among electrocatalysts investigated, the CoMoO₄/GC electrode was the greatest OER active while that the MnMoO₄/GC electrode was the least active. The OER produced low Tafel slopes, ～36, ～43 and ～46 mV respectively on FeMoO₄, CoMoO₄ and CuMoO₄ while it showed the higher Tafel slopes on CrMoO₄(～57 mV), NiMoO₄(～71 mV) and MnMoO₄ (～89 mV).     

Two-dimensional Darcy–Forchheimer flow of a dusty hybrid nanofluid over a stretching sheet with viscous dissipation

The main objective of the present examination is to design a stable mathematical model of a two-phase dusty hybrid nanofluid flow over a stretching sheet with heat transfer in a porous medium, and the Darcy–Forchheimer flow is taken into account with viscous dissipation and melting effect. The equations of motion are reduced to nonlinear ordinary differential equations by considering suitable similarity variables. These dimensionless expressions are solved by a well-known numerical technique known as Runge–Kutta–Fehlberg fourth–fifth order method. The behavioral study and analysis of the velocity and thermal profile in dual phases (fluid phase and dust phase) for diverse values of parameters are estimated using graphs and tables. The result outcome reveals that the velocity gradient declines in the fluid phase and increases in the dust phase for a rise in values of the velocity interaction parameter. Also, the velocity gradients of the both phases diminish for increasing values of the porosity parameter. Furthermore, it is determined that the increase in the value of melting parameter leads to a decline in the thermal gradient of both phases.     

Clinical decision support system for early prediction of Down syndrome fetus using sonogram images

In this paper, the segmentation and extraction of features from ultrasound second trimester fetal images have been presented for early detection of Down syndrome. The region of interest and the edges of the segmented region have been obtained using mean shift analysis and Canny operator, respectively. The prime features such as the nasal bone, the palate and the frontal bone have been segmented for estimating the nasal bone length and frontomaxillary facial angle (FMF). It is observed from the results that the rate of growth of nasal bone length is poor and the FMF angle has been found to increase above 85° for fetus with trisomy 21. This analysis may help the physician for better clinical diagnosis.     

An underwater sensor allocation scheme for a range dependent environment

A series of assumptions is typically made when designing a field of passive underwater sensors. One of the more glaring is range independence throughout an operational area. It is unlikely that a large water space will have uniform acoustic characteristics throughout, i.e., the performance of a sensor will vary based upon its physical location. In an area clearance scenario, where there is no apparent target for an adversary to gravitate towards, such as a ship or a port, it is difficult to determine where the field designer should allocate sensors so that their deployment locations can be planned efficiently. To intelligently allocate sensors, a field designer could first divide an area into sectors of relatively uniform acoustics, based upon variations in acoustic characteristics throughout the area. A prediction of how often a threat submarine will visit each sector can then be made in order to increase the field’s detection capabilities. In this work, an area of interest is divided into sectors of varying geographic size and acoustic characteristics and the probability of visitation to each sector by a threat submarine is determined by solving a minimax matrix game. The Game Theory Field Design (GTFD) model is proposed, which allocates sensors to sectors of relatively uniform acoustics according to the visitation probabilities of an adversary, against adversaries of varying intelligence. In a comparison with two models that do not consider these visitation probabilities and only examine either acoustic characteristics or the size of the sectors, GTFD is shown to offer a significant improvement in terms of overall field detection capability against intelligent adversaries.     

Preparation of the crosslinked poly(vinyl alcohol)/blocked isocyanate prepolymers nanofibers with hydrolyzed products of Scutellariae Radix

We report on the preparation and characterizations of Scutellariae Radix (SR) blended poly(vinyl alcohol) (PVA)/blocked isocyanate prepolymer (BIP) composite nanofibers via electrospinning process. In order to improve the biocompatibility properties, SR biological macromolecules were blended in PVA/BIP composite nanofibers. SEM images revealed that the composite nanofibers were well-oriented and had good incorporation of SR. Ultraviolet (UV) absorbance spectra revealed that the maximum measured absorbance intensities were linearly increased with increasing SR in the composite nanofibers. TEM images revealed a peculiar morphology by the additive SR. This additive SR possesses a lower molecular component which was exhibited at the outside of the nanofibers structure due to strong applied electric field during electrospinning process. These results indicated that the PVA/BIP blended SR composite nanofibers might be utilized for many biomedical applications including control release and wound dressing.     

Synthesis, characterisation, thermal and explosive properties of 4,6-dinitrobenzofuroxan salts

Two new initiatory molecules, e.g. rubidium and cesium salts of 4,6-dinitrobenzofuroxan (DNBF) have been prepared by reacting sodium salt of 4,6-dinitrobenzofuroxan (DNBF) with rubidium nitrate and cesium nitrate, respectively, at 60 °C in aqueous medium. The characterisation of compounds by IR, ¹H-NMR, elemental analysis and metal content is described along with some of the evaluated thermal and explosive properties. The results indicate that cesium salt of DNBF (Cs-DNBF) appears promising initiatory and may suitably replace potassium salt of DNBF (K-DNBF), being used currently in initiatory compositions.     

Synthesis and characterisation of starch/agar nanocomposite films for food packaging application

In the present work cassava starch/agar Ag and ZnO nanocomposite films were prepared by the solution casting method. The structural, physical and antimicrobial properties of the nanocomposite films were studied as a function of the concentration of Ag and ZnO nanoparticles. The results of the thermogravimetric analysis showed 8–15% degradation of both the nanocomposite films at 150°C endorsing the thermal stability of the films. Scanning electron microscopic analysis reveals the uniform blending of Ag and ZnO nanoparticles with a starch/agar matrix with tiny waves like appearance on the surface. The incorporation of Ag and ZnO nanoparticles in the film was found to reduce the moisture content, water solubility and water vapour permeability with increase in the concentration of Ag and ZnO nanoparticles. The growth kinetics study of Pseudomonas aeruginosa and Staphylococcus aureus in the presence of Ag and ZnO blended nanocomposite films showed promising results especially against Gram‐negative P. aeruginosa. Thus, the film synthesised in the present study bears the potential to be used as active packaging material to prevent food from bacterial contamination and spoilage.Inspec keywords: casting, microorganisms, scanning electron microscopy, nanoparticles, food preservation, solubility, thermal analysis, zinc compounds, food processing industry, food products, thermal stability, permeability, antibacterial activity, food packaging, contaminationOther keywords: water vapour permeability, food packaging, solution casting method, structural properties, physical properties, antimicrobial properties, water solubility, agar nanocomposite film, starch nanocomposite film, Pseudomonas aeruginosa, Staphylococcus aureus, bacterial contamination prevention, spoilage prevention, scanning electron microscopic analysis, thermogravimetric analysis, temperature 150.0 degC, Ag, ZnO