Low dielectric materials from fluorinated polybenzoxazines

Fluorinated monomers containing a benzoxazine moiety have been synthesized successfully by preparing the benzoxazines from fluorinated amines (4‐fluoroaniline, 2,4‐difluoroaniline, and 2,3,4‐trifluoroaniline). These monomers were polymerized by step curing process following a cure cycle of 100, 150, 200 and 250°C for 1 h at each temperature. The molecular structure of the monomers and their polymers was characterized by Fourier transform infrared and nuclear magnetic resonance techniques. The synthesized fluorinated polybenzoxazines were able to reduce the dielectric constant to 2.0 for polybenzoxazine from 2,3,4 trifluoroaniline (PTF)‐Bzo at a frequency of 1 MHz. Moreover, they possess high thermal stability and low moisture absorption, which makes it suitable for high‐temperature process of interlayer dielectrics. Copyright © 2014 John Wiley & Sons, Ltd.     

Pinus wallichiana-synthesized silver nanoparticles as biomedical agents: in-vitro and in-vivo approach

ABSTRACT

The current study aims to assess the aqueous extract of Pinus wallichiana stem for the synthesis of small spherical-shaped (10–30?nm) silver nanoparticles (AgNPs) and their in-vitro and in-vivo biomedical applications. The biosynthesized AgNPs were nonmutagenic and safe at all test doses as per Ames and acute toxicity assay (20, 40, 60, and 80?mg/kg). The percent writhing inhibitory effect generated by AgNPs was 42.51, 50.84, and 59.06 at test doses of 10, 20, and 30?mg/kg, respectively. The percent decreased in gastrointestinal tract motility observed was 41.34%, 32.69%, and 28.48% at 10, 20, and 30?mg/kg, respectively. They also showed a significant antipyretic effect after 1, 2, and 3?h in comparison to normal saline. The AgNPs of P. wallichiana showed good antibacterial activity against Acinetobacter baumannii (60% with MIC₅₀?=?2.36?mg/ml and MBC?=?5.0?mg/ml). These nanoparticles also possessed good antioxidant activity of 61.77?±?0.828% and 70.25?±?0.56% at 400 and 500?µg/ml, respectively and lack phytoagglutinin potential. Because of their high potency as biomedical agents, these nanoparticles can be a good alternative to the currently available drugs and approaches.     

Influence of additives on the clouding behavior of amphiphilic drug solutions

The present work focuses on the clouding phenomenon in an amphiphilic drug [amitriptyline (AMT), which is a tricyclic antidepressant] solution. A 50-mM AMT solution prepared in 10 mM of sodium phosphate (SP) buffer was taken where the cloud point (CP) was found to decrease with increasing pH. The same CP decreasing trend (with pH increase) followed in the presence of a fixed concentration (50 mM) of added salts [NaBr, and tetra-n-butylammonium bromide (TBuAB)]. The addition of increasing amounts of quaternary bromides (tetramethylammonium bromide, tetraethylammonium bromide, tetra-n-propylammonium bromide, TBuAB, and tetra-n-pentylammonium bromide) to 50 mM of AMT solution (prepared in 10 mM of SP buffer) caused continuous increase in CP, which was found to be dependent upon the alkyl chain length of that particular salt. The similar type of CP increase was also observed in the presence of conventional (cetyltrimethylammonium bromide and tetradecyltrimethylammonium bromide) and gemini surfactants [bis(hexadecyldimethylammonium)hexane, bis(hexadecyldimethylammonium)pentane, and bis(hexadecyldimethylammonium)butane]. The overall behavior was discussed in terms of electrostatic interactions, micellar growth, and mixed micelle formation.     

Poly (3,4‐ethylenedioxythiophene) γ‐Fe2O3 polymer composite–super paramagnetic behavior and variable range hopping 1D conduction mechanism–synthesis and characterization

The present paper reports the preparation of poly (3,4‐ethylenedioxythiophene) (PEDOT) ferrimagnetic conducting polymer composite by incorporation of ferrite particles in the polymer matrix by emulsion polymerization. Synthesis of PEDOT–γ‐Fe₂O₃ composite was carried out by chemical oxidative polymerization of EDOT with ferrite particles in the presence of dodecylbenzenesulfonic acid (DBSA) that works as dopant as well as surfactant in aqueous medium. The resulting conducting composite possesses saturation magnetization (Ms) value of 20.56 emu/g with a conductivity of 0.4 Scm^?1, which was determined by VSM and four probe technique, respectively. B‐H curve reveals that ferrimagnetic particles of γ‐Fe₂O₃ show super‐paramagnetic behavior at room temperature which was also observed in PEDOT–γ‐Fe₂O₃ composite. The resulting conducting ferrimagnetic composite shows microwave absorption loss of 18.7–22.8 dB in the frequency range of 12.4–18 GHz. Thermogravimetric analysis of the composite revealed that the composite is thermally stable up to 230°C. The characterization of the PEDOT–γ‐Fe₂O₃ composite was carried out using XRD and FTIR spectroscopy. Copyright © 2007 John Wiley & Sons, Ltd.     

Antifungal activity of plumericin and isoplumericin

This study evaluated the in vitro antifungal activity of the chloroform extract of Plumeria bicolor and its phytoconstituents plumericin and isoplumericin against Candida species and Cryptococcus neoformans by measuring the Minimum Inhibitory Concentration (MIC) and Minimum Fungicidal Concentration (MFC). Plumericin's consistently high activity against Candida albicans, C. krusei, C. glabrata, C. tropicalis and Cryptococcus neoformans was more potent than isoplumericin and the standard antifungal drug nystatin suggesting its potential as a drug candidate for candidiasis and cryptococcosis.     

New Insight into Biodegradation of Polylactide (PLA)/Clay Nanocomposites Using Molecular Ecological Techniques

Novel molecular ecological techniques were used to study changes in microbial community structure and population during degradation of polylactide (PLA)/organically modified layered silicates (OMLS) nanocomposites. Cloned gene sequences belonging to members of the phyla Actinobacteria and Ascomycota comprized the most dominant groups of microorganisms during biodegradation of PLA/OMLS nanocomposites. Due to their numerical abundance, members of these microbial groups are likely to play an important role during biodegradation process. This paper presents new insights into the biodegradability of PLA/OMLS nanocomposites and highlights the importance of using novel molecular ecological techniques for in situ identification of new microorganisms involved in biodegradation of polymeric materials.

     

A phosphorus integrated strategy for supercapacitor: 2D black phosphorus–doped and phosphorus-doped materials

In the design and development of energy storage devices, two main factors are considered first high electrochemical performances and second low-cost materials. Phosphorus owns excellent properties such as high carrier mobility, tunable bandgap, anisotropic electronic properties, hydrophilicity, biocompatibility, good electrochemical activity, and high surface area. The interlayer distance of black phosphorus (BP) (0.55 nm) is higher than that of graphene which makes facile ion transportation for supercapacitor application. The phosphorus-based electrode obtained with top-down approaches such as exfoliation and bottom-up approach such as pulsed laser deposition. The BP has been investigated due to its small electronegativity of P which is beneficial to improve the electrical conductivity of the electrode and its abundance nature makes it a desirable candidate for the fabrication of low-cost device. Hence, this review covers the new BP material as the advanced materials for the commercial realization of advanced supercapacitors. This is the first review on phosphorus integrated supercapacitor devices. This review will give a brief idea about BP to researchers in search of outstanding supercapacitor configurations with different electrodes and electrolytes.     

Impacting the Remedial Potential of Nano Delivery-Based Flavonoids for Breast Cancer Treatment

Breast cancer persists as a diffuse source of cancer despite persistent detection and treatment. Flavonoids, a type of polyphenol, appear to be a productive option in the treatment of breast cancer, because of their capacity to regulate the tumor related functions of class of compounds. Plant polyphenols are flavonoids that appear to exhibit properties which are beneficial for breast cancer therapy. Numerous epidemiologic studies have been performed on the dynamic effect of plant polyphenols in the prevention of breast cancer. There are also subclasses of flavonoids that have antioxidant and anticarcinogenic activity. These can regulate the scavenging activity of reactive oxygen species (ROS) which help in cell cycle arrest and suppress the uncontrolled division of cancer cells. Numerous studies have also been performed at the population level, one of which reported a connection between cancer risk and intake of dietary flavonoids. Breast cancer appears to show intertumoral heterogeneity with estrogen receptor positive and negative cells. This review describes breast cancer, its various factors, and the function of flavonoids in the prevention and treatment of breast cancer, namely, how flavonoids and their subtypes are used in treatment. This review proposes that cancer risk can be reduced, and that cancer can be even cured by improving dietary intake. A large number of studies also suggested that the intake of fruit and vegetables is associated with reduced breast cancer and paper also includes the role and the use of nanodelivery of flavonoids in the healing of breast cancer. In addition, the therapeutic potential of orally administered phyto-bioactive compounds (PBCs) is narrowed because of poor stability and oral bioavailability of compounds in the gastrointestinal tract (GIT), and solubility also affects bioavailability. In recent years, creative nanotechnology-based approaches have been advised to enhance the activity of PBCs. Nanotechnology also offers the potential to become aware of disease at earlier stages, such as the detection of hidden or unconcealed metastasis colonies in patients diagnosed with lung, colon, prostate, ovarian, and breast cancer. However, nanoformulation-related effects and safety must not be overlooked. This review gives a brief discussion of nanoformulations and the effect of nanotechnology on herbal drugs.