Roles of anti- and pro-oxidant potential of cinnamic acid and phenylpropanoid derivatives in modulating growth of cultured cells

Food Science and Biotechnology - Cinnamic acid (CiA) and phenylpropanoid derivatives are widely distributed in plant foods. In this study, anti- and pro-oxidant properties of the derivatives and...     

Changes in chemical stability and bioactivities of curcumin by ultraviolet radiation

Curcumin, a yellow pigment from turmeric (Curcuma longa), has shown various health beneficial effects. In the present study, changes in the chemical stability and bioactivities of curcumin by UV radiation were investigated. Curcumin degradation in water or phosphate buffered saline was accelerated under UV radiation (254 nm); the residual levels of curcumin were 36.9 and 16.8%, respectively, after 24 h radiation. Decomposition of curcumin by UV was more prominent at higher pHs. ABTS radical scavenging activity of curcumin after 24 h radiation was reduced significantly (p<0.05), whereas scavenging activities of DPPH radical and nitric oxide were not significantly changed (p>0.05) as compared to those of curcumin stored at a dark place. Stabilities and bioactivities of curcumin powder treated under UV radiation were, however, not significantly changed (p>0.05). The present results suggest that certain processing or storing conditions exposed to UV radiation could affect stability and bioactivities of curcumin.     

Super‐Absorbent Polymer Valves and Colorimetric Chemistries for Time‐Sequenced Discrete Sampling and Chloride Analysis of Sweat via Skin‐Mounted Soft Microfluidics

This paper introduces super absorbent polymer valves and colorimetric sensing reagents as enabling components of soft, skin‐mounted microfluidic devices designed to capture, store, and chemically analyze sweat released from eccrine glands. The valving technology enables robust means for guiding the flow of sweat from an inlet location into a collection of isolated reservoirs, in a well‐defined sequence. Analysis in these reservoirs involves a color responsive indicator of chloride concentration with a formulation tailored to offer stable operation with sensitivity optimized for the relevant physiological range. Evaluations on human subjects with comparisons against ex situ analysis illustrate the practical utility of these advances.     

Assessment of two-parameter mixed models for large eddy simulations of transitional and turbulent flows

In the present study, improved two-parameter mixed models for large eddy simulations are proposed based on previous two-parameter mixed models of Salvetti and Banerjee [1] and Horiuti [2]. The subgrid-scale (SGS) stress in our models is decomposed into the modified Leonard stress, modified cross stress and modified SGS Reynolds stress terms. Although the modified Leonard stress term is explicitly calculated based on the scale-similarity, the modified cross stress term is built using an extension of the filtered Bardina model proposed by Horiuti [3] for better predictions of the interaction between resolved and unresolved scales (i.e., energy exchange). The modified SGS Reynolds stress is modeled by the dynamic Smagorinsky model or by a dynamic global model, leading to two unknown model coefficients for the modified cross stress and the modified SGS Reynolds stress terms. In order to demonstrate the reliability of the proposed SGS models, large eddy simulations of two types of flows (i.e., a fully developed turbulent channel flow and a transitional boundary layer flow) are performed. It is shown that the modified cross stress term makes an important contribution to the accurate predictions of such flows because the emergence of negative SGS dissipation (backward scatter) by the modified cross stress term decreases the excessive positive SGS dissipation (forward scatter). A direct comparison of the turbulent statistics with those from previous SGS models shows that the proposed SGS models result in better prediction performance both in transitional and turbulent flows.

     

Soft Wearable Systems for Colorimetric and Electrochemical Analysis of Biofluids

Wearable monitoring systems provide valuable insights about the state of wellness, performance, and progression of diseases. Although conventional wearable systems have been effective in measuring a few key biophysical markers, they offer limited insights into biochemical activity and are otherwise cumbersome in ambulatory modes of use, relying on wired connections, mechanical straps, and bulky electronics. Recent advances in skin‐interfaced microfluidics, stretchable/flexible electronics, and mechanics have created new wearable systems with capabilities in real‐time, noninvasive analysis of sweat biochemistry in combination with biophysical metrics. Here, the latest technologies in multifunctional sweat sensing systems are presented with a focus on novel microfluidic designs, fully‐integrated wireless electrochemical sensors, and hybrid biochemical/biophysical sensing capabilities, creating real‐time physiological insights.     

Analysis of chemical interactions of (−)-epigallocatechin-3-gallate, a major green tea polyphenol, with commonly-consumed over-thecounter drugs

In the present study, changes in chemical stabilities were investigated after incubation of commonly-consumed over-the-counter (OTC) drugs with (−)-epigallocatechin-3-gallate (EGCG), a major green tea polyphenol. Stability of EGCG was significantly increased in the presence of millimolar levels of acetylsalicylic acid (Asp); EGCG stability was not affected by ibuprofen and acetaminophen (AAP). Stability of AAP was not altered in the presence of EGCG during 24 hr-incubation at pH 2.0, 7.4, and 8.0. Asp stability and formation of salicylic acid were not affected by EGCG at pH 2.0 either. The present study may provide basic information for chemical interactions between dietary polyphenols and OTC drugs.     

Antioxidant properties and cytotoxic effects of fractions from glasswort (<Emphasis Type="Italic">Salicornia herbacea</Emphasis>) seed extracts on human intestinal cells

Glasswort (Salicornia herbacea L.) is a halophyte that grows in the salt marshes and has been used as a seasoned vegetable and a traditional folk medicine. In the present study, the antioxidant properties and cytotoxic effects of glasswort seeds on human colon and intestinal cells were investigated. A series of solvent fractions, including fractions of hexane (Fr.H), ethyl ether (Fr.E), ethyl acetate (Fr.EA), and water (Fr.W) were prepared from 70% methanol extract of glasswort seeds. Fr.EA contained the highest level of total polyphenols and flavonoids followed by Fr.E. Radicals of 1,1-diphenyl-2-picrydrazyl and 2,2′-azinobis-(3-ethyl-benzothiazoline-6-sulfonic acid), and nitric oxide were most effectively scavenged by Fr.EA. Among the solvent fractions, Fr.E showed the most potent cytotoxic effects on HCT 116 and HT-29 colon cancer cells, and was significantly less toxic to INT-407 normal immortalized intestinal cells. The selective toxicity between normal and cancer cells was not observed in cells treated with Fr.H or Fr.EA. Fr.W rather stimulated cell growth by 10–20% in the range of 100–400 μg/mL. The results indicate that the fractions from seeds of glasswort have potent antioxidant and cytotoxic effects, and can be used as a dietary source for medicinal application.     

Formation and behavior of Kirkendall voids within intermetallic layers of solder joints

The sub-micron void called “Kirkendall void” has been widely observed within intermetallic compound (IMC) layers in solder joints of semiconductor package interconnections that include both the first level interconnection for a silicon die to a substrate and the second level interconnection for the substrate to a PCB board. Based on many researches on Kirkendall void through a variety of variables, it has been demonstrated as a critical reliability risk within various binary and ternary IMC layers of solder joints in electronic packaging industry. Even, it is more crucial for fine pitch and high complexity in chip-scale electronic packaging. Hence, it is necessarily demanding to review the dependency and influence of critical variables for Kirkendall void formation and behavior in the basis of solid and solid–liquid state interdiffusion process, time and temperature-dependent kinetic process, and morphology and microstructure change of IMCs. Specifically, we reviewed the initial formation, growth and behaviors of Kirkendall void in: (1) short and long-term interfacial reaction by aging in different time and temperatures (2) multiple reflows with different peak temperature (3) annealing after reflow and (4) electromigration, within IMCs of solder joints. Probably, this study may serve as conceptually helpful references to the overall understanding of formation, growth and behavior of Kirkendall void in interfacial reaction of solder joints.