Synthesis and Evaluation of a Nonsteroidal Anti-inflammatory Polymeric Prodrug for Sustained and Site-Specific Delivery

A new polymerizable drug derivative of diclofenac sodium was synthesized and characterized in terms of melting point, elemental analysis, and infrared spectroscopy. It was then polymerized to obtain a new polymeric prodrug. The prodrug was evaluated for its viscosity, drug content, and in vitro drug release behavior at pH 1.2 and 7.2. The in vitro studies showed that the drug release takes place predominantly at the higher pH and in a sustained manner, as hypothesized. Stability at room temperature, bioavailability, and ulcer-inducing effect of the polymeric prodrug were also studied. The investigations showed complete drug absorption from the polymeric prodrug with a statistically significant decrease in ulcer scoring effect, thus showing its potential for site-specific and sustained drug delivery.     

Steady-state frictional sliding contact on surfaces of plastically graded materials

Tailored gradation in elastic–plastic properties is known to offer avenues for suppressing surface damage during normal indentation and sliding contact. In tribological applications, sliding contact analysis provides a more representative mechanism for fundamental understanding and design as it offers a tool to test materials under conditions of controlled abrasive wear. However, no such study exists for plastically graded materials, although the sliding behavior for elastically graded materials has been reasonably well understood. This study has established a systematic methodology to quantify the mechanics of steady-state frictional sliding response for a plastically graded material. Specifically, the effect of linear gradient in yield stress on the frictional sliding response is examined through parametric finite-element (FEM) computation of the instrumented scratch test. Gradients in yield strength affect both the load carrying capacity of the surface and its pile-up around the sliding indenter. An increase in yield strength with distance beneath the surface shifts the peak values of von Mises stress below the surface, thus improving the resistance of the surface to onset of plasticity and damage. For a given elastic–plastic property, an increasing yield strength gradient causes a reduction in total apparent friction through a reduction in the ploughing coefficient. The contact-load-bearing capacity of plastically graded surfaces follows a similar trend during indentation and scratch. However, significant differences between the pile-up and the friction response are observed between normal indentation and steady-state frictional sliding. In particular, an increase in interfacial friction is found to cause an increase in pile-up during scratch, while it causes a decrease in pile-up during indentation. The implications of the present results to the design of graded surfaces are discussed.     

Hierarchical Self‐Organization of Nanomaterials into Two‐Dimensional Arrays Using Functional Polymer Scaffold

Fabrication of two and three‐dimensional nanostructures requires the development of new methodologies for the assembly of molecular/macromolecular objects on substrates in predetermined arrangements. Templated self‐assembly approach is a powerful strategy for the creation of materials from assembly of molecular components or nanoparticles. The present study describes the development of a facile, template directed self‐assembly of (metal/organic) nanomaterials into periodic micro‐ and nanostructures. The positioning and the organization of nanomaterials into spatially well‐defined arrays were achieved using an amphiphilic conjugated polymer‐aided, self‐organization process. Arrays of honeycomb patterns formed from conjugated C₁₂PPPOH film with homogenous distribution of metal/organic nanomaterials. Our approach offers a straightforward and inexpensive method of preparation for hybrid thin films without environmentally controlled chambers or sophisticated instruments as compared to multistep micro‐fabrication techniques.     

Collaboration profile of theoretical population genetics speciality

Traces the growth of collaborated and funded research as reflected in research papers in theoretical population genetics research speciality from 1916–80 through a case study. Analyses the proportion and extent of collaborated papers, averge number of authorship per paper, and collaborative coefficient index of research papers thereby giving an overall perspective of the growth of professionalism in the field. Studies the relation between collaboration, productivity, and funding of research papers in theoretical population genetics. Classifies the total collaborative papers/authors by type of collaboration and studies the trends and shifts in the nature and type of collaborative research over the years.     

Estimation of cutting forces and surface roughness for hard turning using neural networks

Metal cutting mechanics is quite complicated and it is very difficult to develop a comprehensive model which involves all cutting parameters affecting machining variables. In this study, machining variables such as cutting forces and surface roughness are measured during turning at different cutting parameters such as approaching angle, speed, feed and depth of cut. The data obtained by experimentation is analyzed and used to construct model using neural networks. The model obtained is then tested with the experimental data and results are indicated.     

Silver nanorods induced oxidative stress and chromosomal aberrations in the Allium cepa model

The production of different size and shape silver nanoparticles (AgNPs) has increased considerably in recent years due to several commercial and biological applications. Here, rod‐shaped AgNPs (SNRs) were prepared using the microwave‐assisted method and characterised by ultraviolet–visible spectroscopy, and transmission electron microscopy analysis. The present study aims to investigate the cyto–genotoxic effect of various concentrations (5, 10, and 15 µM) of SNRs using Allium cepa model. As a result, concentration‐dependent cyto–genotoxic effect of SNRs was observed through a decrease in the mitotic index, and an increase in the chromosomal aberrations such as chromosome break, disturbed metaphase, and anaphase bridge. To check the impact of Ag⁺ ions, 15 µM silver nitrate (AgNO₃) was prepared and tested in all the assays. Furthermore, cell viability and different reactive oxygen species assays were performed to test the cytotoxicity evaluation of SNRs. The authors found that in all the tested assays, SNRs at high concentrations (15 µM) and AgNO₃ (15 µM) were observed to cause maximal damage to the roots. Therefore, the current study implies that the cytotoxicity and genotoxicity of SNRs were dependent on the concentration of SNRs.Inspec keywords: ultraviolet spectra, biomedical materials, silver, cellular biophysics, nanorods, toxicology, visible spectra, nanoparticles, nanofabrication, transmission electron microscopy, nanomedicine, aberrations, microwave materials processingOther keywords: biological applications, rod‐shaped AgNPs, microwave‐assisted method, ultraviolet‐visible spectroscopy, transmission electron microscopy, chromosomal aberrations, chromosome break, silver nitrate, reactive oxygen species assays, cytotoxicity, genotoxicity, silver nanorods, oxidative stress, shape silver nanoparticles, concentration‐dependent cyto‐genotoxic effect, Allium cepa model, mitotic index, disturbed metaphase, anaphase bridge, cell viability, cytotoxicity evaluation, Ag     

Optical and electrical properties of hybrid photovoltaic devices from poly (3-phenyl hydrazone thiophene) (PPHT) and TiO2 blend films

Bulk heterojunction photovoltaic devices based on blends of a conjugated polymer poly (3-phenyl hydrazone thiophene) (PPHT) as electron donor and titanium dioxide (TiO₂) particles as an electron acceptor (n-type wide band gap semiconductor) have been studied. The blend films were spin coated from a common solvent mixture. The absorption peak and shape of the absorption spectra of PPHT:TiO₂ (40 vol%) indicate that it is a superposition of the absorption of PPHT and TiO₂. From the cyclic voltammetry measurements, we have estimated the values of levels of the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) for PPHT. A strong fluorescence quenching indicates that the exciton dissociation and charge separation occurs successfully at PPHT:TiO₂ interfaces formed in the bulk. This also enhances the possibility that the separated charges will reach the electrodes before recombining. Experimentally observed current–voltage characteristics of this device has been explained employing the metal–insulator–metal (MIM) model, where the intimate mixture of electron accepting and hole accepting materials is treated as a homogeneous intrinsic semiconductor. In this device, holes are solely transported along the pure donor phase and electrons transported along the paths of acceptor phase. Effect of TiO₂ concentrations in the blend and thermal annealing of device has been described is detail. For low concentration of TiO₂ below 20% the device performance is poor than that for pure PPHT, while for higher concentration of TiO₂ significant improvement was obtained. The thermal annealing of the device also improves the photovoltaic response of the device, which may be due to the reduction in the recombination process.     

Effect of immobile water content on contaminant transport in unsaturated zone

The effect of immobile water content on contaminant advection and dispersion in unsaturated porous media has been studied using a formulation which assumes that even in the immobile liquid zone, there occurs minor liquid flow. An approach is proposed for computing this liquid velocity. One dimensional numerical simulation is carried out to study the effect of immobile water content on the time of appearance of contaminant at the bottom of an unsaturated column. The numerical model developed is verified using analytical solutions for simple advective-dispersive cases. From the simulations, it was observed that increase in the immobile water content leads to quicker appearance of contaminant.     

Use of micelles in photogalvanic cell for solar energy conversion and storage: Azur A-glucose system

Sodium lauryl sulphate (NaLS), tetradecyl trimethyl ammonium bromide (TTAB) and Brij-35 were used in a photogalvanic cell containing azur A as a photosensitizer and glucose as a reductant for solar energy conversion and storage. The photopotential and photocurrent generated by the cell in the presence of NaLS were 811.0 mV and 1470 μA, respectively. The effect of variation of the concentrations of the surfactants on the electrical output, the fill factor, the conversion efficiency and the performance of the cell in the dark was studied in detail.