Carbohydrate crosslinked biocompatible polyurethanes: Synthesis,characterization, and drug delivery studies

A series of novel polyurethanes (PUs) with carbohydrate crosslinkers was synthesized. The drug loading and release kinetics were studied by using lamotrigine as a model drug. The polymers were designed in such a way that the drug release was tailored by differences in the stoichiometry of polymers. All the PUs were characterized for thermal and morphological properties by using differential scanning calorimetry and thermogravimetric analysis and scanning electron microscope , respectively. The encapsulation of drug inside PU matrix was confirmed via Fourier transform ‐ infrared (FT‐IR) spectra and scanning electron microscope . The kinetics and release mechanisms were observed to be a function of stoichiometric parameters such as type of crosslinker, polyol/crosslinker ratio and polyol/chain extender ratio. All the PUs were observed to be non‐cytotoxic in normal lung cell line L132. The synthesized PUs exhibited good mechanical strength, tunable release rates and biocompatibility that can be utilized in biomedical applications like wound dressing, biomedical implants , and drug delivery carriers. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42223.     

A Hybrid Fractal Metamaterial Inspired Multiband Antenna for Wireless Applications

Wireless Personal Communications - In this paper a multiband (hepta-band) antenna loaded with hybrid fractal structures and metamaterial cell (SRR/CSRR) is proposed to cover the wireless...     

Sequency codes for palmprint recognition

This paper presents a new palmprint scheme named as Sequency code (SeqC) which exploits symmetric and asymmetric Gabor filtered responses at different orientations. Concatenation of the zero crossings of these symmetric and asymmetric Gabor responses is performed, and bit transition among concatenated zero crossings is counted at corresponding locations to compute Sequency plane, Seq. Finally, Seq is encoded into Sequency code bit plane features SeqC. The Sequency code requires less computations and time in feature extraction process because of its simple fusion strategy. Performance of Sequency code is validated by carrying out large number of experiments with three different standard databases, i.e., PolyU 2D, PolyU 2nd version, IITD, and Multispectral databases.     

Tunable Emission in Heteroepitaxial Ln‐SURMOFs

By using a layer‐by‐layer (LbL) approach, lanthanide‐based, monolithic metal–organic framework (MOF) thin films are fabricated for optical applications. In particular, the LbL approach allows manufacturing of heteroepitaxial Tb(III)‐Eu(III)(BTC) coatings with precise thickness control. Adjusting the Tb(III)‐to‐Eu(III) ratio allows tuning of the emission color. The hetero‐multilayer architecture makes it possible to suppress the direct Tb(III)‐to‐Eu(III) energy transfer, an unwanted phenomenon present in the corresponding mixed‐metal bulk MOF structures. The resulting Ln‐MOF thin films, or Ln‐surface‐anchored MOFs (SURMOFs), are characterized by X‐ray diffraction, infra‐red reflection absorption spectroscopy, UV–vis, and photoluminescence measurements. The results demonstrate that the heteroepitaxial SURMOF architectures carry huge potential for fabricating optical coatings for a wide range of applications.     

A vertex‐fed hexa‐band frequency reconfigurable antenna for wireless applications

Present article embodies the design and analysis of an octagonal shaped split ring resonator based multiband antenna fed at vertex for wireless applications with frequency‐band reconfigurable characteristics. The proposed antenna is printed on FR4 substrate with electrical dimension of 0.4884 λ × 0.4329 λ × 0.0178 λ (44 × 39 × 1.6 mm³), at lower frequency of 3.33 GHz. The antenna consists of SRR based vertex fed octagonal ring as the radiation element and switchable reclined L‐shaped slotted ground plane. Antenna achieves six bands for wireless standards viz: upper WLAN (5.0/5.8 GHz), lower WiMAX (3.3 GHz), super extended C‐band (6.6 GHz), middle X band (9.9 GHz—for space communication), and lower K_U band (15.9 GHz—for satellite communication systems operating band). Stable radiation patterns are observed for the operating bands with low cross polarization. The proposed design achieves hexa band characteristics during switching ON state of PIN diode located at reclined L‐shaped slot in the ground plane. Experimental characteristic of antenna shows close agreement with those obtained by simulation of the proposed antenna.     

Predictive modeling of multi-track laser hardening of AISI 4140 steel

Laser hardening provides benefits over the conventional hardening processes, including minimum distortion in the parts and the absence of a quenchant. This process is also faster than conventional hardening processes and can be used for selective hardening of specific areas of components. One known problem with laser hardening in steels, however, is back tempering when a large area is hardened by multiple, overlapping passes. This study focused on the development of a numerical model to predict the back tempering in multi-track laser hardening. A tempering model was combined with existing models of thermal behavior and phase change kinetics, which were developed earlier in the authors’ group, to predict three-dimensional hardness profiles after multiple track laser hardening. The combined model was first validated through multi-track laser hardening tests and then used to predict and optimize the laser hardened case depth in multi-track laser hardening of AISI 4140 steel. The predictions and parameters optimized to obtain maximum case depth with the least variation along width of the hardened zone were experimentally verified. Case depths up to 2 mm were obtained with 5 mm overlapping of laser tracks.     

Heterointerfaces in semiconductor nanowires

Semiconductor nanowires have attracted considerable recent interest due to their unique properties, including their highly anisotropic geometry, large surface-to-volume ratio, and carrier and photon confinement. Currently, tremendous efforts are devoted to the rational synthesis of advanced nanowire heterostructures. Yet, if functional devices are to be made from these materials, precise control over their composition, structure, morphology, and dopant concentration must be achieved. Their fundamental properties must also be carefully investigated since the presence of a large surface and interfacial area in nanowires can profoundly alter their performance. In this article, the progress, promise, and challenges in the area of nanowire heterostructured materials are reviewed, with particular emphasis on the effect of different types of heterointerfaces on device properties.     

Milk Derived Antimicrobial Bioactive Peptides: A Review

In recent decades, bioactive peptides have attracted increasing interest as health promoting functional foods. A variety of naturally formed bioactive peptides have been found in fermented dairy products such as yogurt, sour milk, and cheese. Initially these peptides are inactive within the sequence of the parent protein molecule and can be generated by gastrointestinal digestion of milk, fermentation of milk with proteolytic starter cultures, and/or hydrolysis by proteolytic enzymes. Milk derived peptides exert a number of health beneficial activities, even upon oral administration. Bioactive peptides have a great impact on major body systems including the digestive, nervous, endocrine, cardiovascular, diabetes type II, obesity, and immune systems. Antimicrobial peptides are also an important ingredient of innate immunity, especially at mucosal surfaces such as lungs and small intestine that are constantly exposed to a range of potential pathogens. Therefore, it plays an important role in boosting natural immune protection by reducing the risk of chronic diseases. Bioactive peptides are considered as potent drugs with well-defined pharmacological residues and also used to formulate health-enhancing nutraceuticals.     

A partial Granger causality based method for analysis of parameter interactions in bioreactors

In this article, we utilize the concept of partial Granger causality to study the penicillin production process under several operating conditions. We propose a graph-theoretic template (causal network) based method for intelligent process monitoring. We validate our results with the aid of existing knowledge and available literature. The proposed method is quite general and can be extended to analyze several physical, chemical or biological systems.     

Importance of Deoxyribose Degradation Assay for Evaluating Hydroxyl Radical Scavenging Activity of Punica Extract

Punica granatum L. (Family: Punicaceae), commonly known as pomegranate (Anar) has been used traditionally as medicine to treat a number of diseases and disorders. Various parts of the plant and their active constituents are known to possess diverse biological activity. However, little is known about the antioxidant potential of pomegranate fruit peel, which is otherwise considered as waste. Therefore, the concentration-dependent hydroxyl radical scavenging ability of Punica granatum seed and peel extracts (alcoholic and aqueous) using deoxyribose degradation assay were analyzed and compared. The hydroxyl radical scavenging activity at different concentrations of extract (10 to 250 μg/mL) both in presence and/or absence of ascorbic acid and ethylenediamine tetra acetic acid was determined. It was observed that a higher concentration of extract suppresses scavenging activity and lower promotes antioxidant property. Based on the observations, it may be inferred that pomegranate extract, especially from the spent/waste prt, has a strong antioxidant property as assessed by its property of scavenging hydroxyl radical formation.