Piezoelectric power harvesting devices: An overview

This article reviews the fundamental behavior of piezoelectric for applications in sensors and energy harvesting technologies. In fact, many devices and applications are evolving day-to-day depending on smart materials technology such as, scanning probe microscope (SPM) and cigarette lighters. Today, vibration based energy harvesting via piezoelectric materials has become one of the most prominent ways to provide a limited energy for self-powered wireless sensor and low power electronics. This review provides an insight that involves mathematical modeling of constitutive equations, lumped parameter model, mechanisms of piezoelectric energy conversion, and operating principle of a piezoelectric energy harvesting system. This article also focuses on the dielectric, piezoelectric, mechanical, and pyroelectric properties of piezoelectric and pyroelectric materials open to use from single crystal such as PMN-PT through ceramics PZT and polymers such as PVDF. Recent important literature is also reviewed along with energy harvesting devices proposed for use in industrial and biomedical applications

Functional and Probiotic Attributes of an Indigenous Isolate of Lactobacillus plantarum

BACKGROUND:Probiotic microorganisms favorably alter the intestinal microflora balance, promote intestinal integrity and mobility, inhibit the growth of harmful bacteria and increase resistance to infection. Probiotics are increasingly used in nutraceuticals, functional foods or in microbial interference treatment. However, the effectiveness of probiotic organism is considered to be population-specific due to variation in gut microflora, food habits and specific host-microbial interactions. Most of the probiotic strains available in the market are of western or European origin, and a strong need for exploring new indigenous probiotic organisms is felt. METHODS AND FINDINGS:An indigenous isolate Lp9 identified as Lactobacillus plantarum by molecular-typing methods was studied extensively for its functional and probiotic attributes, viz., acid and bile salt tolerance, cell surface hydrophobicity, autoaggregation and Caco-2 cell-binding as well as antibacterial and antioxidative activities. Lp9 isolate could survive 2 h incubation at pH 1.5-2.0 and toxicity of 1.5-2.0% oxgall bile. Lp9 could deconjugate major bile salts like glycocholate and deoxytaurocholate, indicating its potential to cause hypocholesterolemia. The isolate exhibited cell-surface hydrophobicity of approximately 37% and autoaggregation of approximately 31%. Presence of putative probiotic marker genes like mucus-binding protein (mub), fibronectin-binding protein (fbp) and bile salt hydrolase (bsh) were confirmed by PCR. Presence of these genes suggested the possibility of specific interaction and colonization potential of Lp9 isolate in the gut, which was also suggested by a good adhesion ratio of 7.4+/-1.3% with Caco-2 cell line. The isolate demonstrated higher free radical scavenging activity than standard probiotics L. johnsonii LA1 and L. acidophilus LA7. Lp9 also exhibited antibacterial activity against E. coli, L. monocytogenes, S. typhi, S. aureus and B. cereus. CONCLUSION:The indigenous Lactobacillus plantarum Lp9 exhibited high resistance against low pH and bile and possessed antibacterial, antioxidative and cholesterol lowering properties with a potential for exploitation in the development of indigenous functional food or nutraceuticals

Allosteric inhibitors of plasma membrane Ca2+ pumps: Invention and applications of caloxins

Plasma membrane Ca2+ pumps (PMCA) play a major role in Ca2+ homeostasis and signaling by extruding cellular Ca2+ with high affinity. PMCA isoforms are encoded by four genes which are expressed differentially in various cell types in normal and disease states. Therefore, PMCA isoform selective inhibitors would aid in delineating their role in physiology and pathophysiology. We are testing the hypothesis that extracellular domains of PMCA can be used as allosteric targets to obtain a novel class of PMCA-specific inhibitors termed caloxins. This review presents the concepts behind the invention of caloxins and our progress in this area. A section is also devoted to the applications of caloxins in literature. We anticipate that isoform-selective caloxins will aid in understanding PMCA physiology in health and disease. With strategies to develop therapeutics from bioactive peptides, caloxins may become clinically useful in cardiovascular diseases, neurological disorders, retinopathy, cancer and contraception