An Embeddable Strain Sensor with 30 Nano-Strain Resolution based on Optical Interferometry

A cost-effective, robust and embeddable optical interferometric strain sensor with nanoscale strain resolution is presented in this paper. The sensor consists of an optical fiber, a quartz rod with one end coated with a thin gold layer, and two metal shells employed to transfer the strain and orient and protect the optical fiber and the quartz rod. The optical fiber endface, combining with the gold-coated surface, forms an extrinsic Fabry—Perot interferometer. The sensor was firstly calibrated, and the result showed that our prototype sensor could provide a measurement resolution of 30 nano-strain (nε) and a sensitivity of 10.01 µε/ µm over a range of 1000 µε. After calibration of the sensor, the shrinkage strain of a cubic brick of mortar in real time during the drying process was monitored. The strain sensor was compared with a commercial linear variable displacement transducer, and the comparison results in four weeks demonstrated that our sensor had much higher measurement resolution and gained more detailed and useful information. Due to the advantages of the extremely simple, robust and cost-effective configuration, it is believed that the sensor is significantly beneficial to practical applications, especially for structural health monitoring

Probing Nanostrain via a Mechanically Designed Optical Fiber Interferometer

We propose an extrinsic Fabry-Perot interferometer (EFPI)-based optical fiber sensor with a novel mechanical design for nano-scale strain measurement. In our proposed sensor, a designed mechanical structure consists of a cylinder and a square column attached to a stainless steel substrate. This simple and compact structure along with a fiber ceramic ferrule and a gold-coated reflective mirror as a packaged EFPI sensor can resolve nano-scale strain with temperature self-compensation. In comparison with the existing nanostrain sensing methods, no reference sensors and complicated configurations are needed. The strain measured by our proposed sensor ranges from 0 to 677 nε with a measurement accuracy of ±5 nε. This robust and easy-to-build geometry-based nano-scale strain sensor has great potential in nanotechnology, geophysical research, seismic monitoring, and other practical applications

Bioactive glass activates VEGF paracrine signaling of cardiomyocytes to promote cardiac angiogenesis

The heart contains a wide range of cell types, which are not isolated but interact with one another via multifarious paracrine, autocrine and endocrine factors. In terms of cardiac angiogenesis, previous studies have proved that regulating the communication between cardiomyocytes and endothelial cells is efficacious to promote capillary formation. Firstly, this study investigated the effect and underlying mechanism of bioactive glass (BG) acted on vascular endothelial growth factor (VEGF) paracrine signaling in cardiomyocytes. We found that bioactive ions released from BG significantly promoted the VEGF production and secretion of cardiomyocytes. Subsequently, we proved that cardiomyocyte-derived VEGF played an important role in mediating the behavior of endothelial cells. Further research showed that the phosphoinositide 3-kinase (PI3K)/protein kinase B (Akt)/hypoxia-inducible factor 1α (HIF-1α) signaling pathway was upregulated by BG, which was involved in VEGF expression of cardiomyocytes. This study revealed that by means of modulating cellular crosstalk via paracrine signaling of host cells in heart is a new direction for the application of BGs in cardiac angiogenesis.</p

Facile, Fast-Responsive, and Photostable Imaging of Telomerase Activity in Living Cells with a Fluorescence Turn-On Manner

In situ detecting and monitoring intracellular telomerase activity is significant for cancer diagnosis. In this work, we report a facile and fast-responsive bioprobe for in situ detection and imaging of intracellular telomerase activity with superior photostability. After transfected into living cells, quencher group labeled TS primer (QP) can be extended in the presence of intracellular telomerase. Positive charged TPE-Py molecules (AIE dye) will bind to the primer as well as extension repeated units, producing a telomerase activity-related turn-on fluorescence signal. By incorporating positive charged AIE dye and substrate oligonucleotides, in situ light-up imaging and detection of intracellular telomerase activity were achieved. This strategy exhibits good performance for sensitive in situ tracking of telomerase activity in living cells. The practicality of this facile and fast-responsive telomerase detection method was demonstrated by using it to distinguish tumor cells from normal cells and to monitor the change of telomerase activity during treatment with antitumor drugs, which shows its potential in clinical diagnostic and therapeutic monitoring

Inhibitory Effects of Methyl trans-Cinnamate on Mushroom Tyrosinase and Its Antimicrobial Activities

The control of food browning and growth of disease-causing microorganisms is critical to maintaining the quality and safety of food. Tyrosinase is the key enzyme in food browning. The inhibitory effect of methyl trans-cinnamate on the activity of tyrosinase has been investigated. Methyl trans-cinnamate can strongly inhibit both monophenolase and diphenolase activity of mushroom tyrosinase. When the concentration of methyl trans-cinnamate reached 2.5 mM, the lag time was lengthened from 32 to 160 s and the steady-state activity was lost about 65%. The IC50 value was 1.25 mM. For the diphenolase activity, the inhibition of methyl trans-cinnamate displayed a reversible and noncompetitive mechanism. The IC50 value was 1.62 mM, and the inhibition constant (K-I) was determined to be 1.60 mM. Moreover, the antibacterial activity against Escherichia coli, Bacillus subtilis and Staphyloccocus aureus and antifungal activity against Candida albicans were tested. The results showed that methyl trans-cinnamate possessed an antimicrobial ability.National Key Technology R & D Program of China [2007BAD07B06]; Natural Science Foundation of China [30570408]; Science and Technology Foundation of Fujian Province [2007N0051]; Program for Innovative Research Team in Science and Technology in Fujian Province Universit

Evolutionarily significant A-to-I RNA editing events originated through G-to-A mutations in primates

Abstract Background Recent studies have revealed thousands of A-to-I RNA editing events in primates, but the origination and general functions of these events are not well addressed. Results Here, we perform a comparative editome study in human and rhesus macaque and uncover a substantial proportion of macaque A-to-I editing sites that are genomically polymorphic in some animals or encoded as non-editable nucleotides in human. The occurrence of these recent gain and loss of RNA editing through DNA point mutation is significantly more prevalent than that expected for the nearby regions. Ancestral state analyses further demonstrate that an increase in recent gain of editing events contribute to the over-representation, with G-to-A mutation site as a favorable location for the origination of robust A-to-I editing events. Population genetics analyses of the focal editing sites further reveal that a portion of these young editing events are evolutionarily significant, indicating general functional relevance for at least a fraction of these sites. Conclusions Overall, we report a list of A-to-I editing events that recently originated through G-to-A mutations in primates, representing a valuable resource to investigate the features and evolutionary significance of A-to-I editing events at the population and species levels. The unique subset of primate editome also illuminates the general functions of RNA editing by connecting it to particular gene regulatory processes, based on the characterized outcome of a gene regulatory level in different individuals or primate species with or without these editing events

Designing Superhydrophobic Porous Nanostructures with Tunable Water Adhesion

Basic principles of capillary-induced adhesion and roughness-enhanced hydrophobicity are utilized to design three superhydrophobic porous-nanostructure models whose adhesion forces ranged from strong to weak. The design idea is well supported by experimental results, which indicated that adhesive forces may be tailored by modifying structural morphologies to manipulate solid-liquid contact behavior and air-pocket composition in open or sealed systems.National Nature Science Foundation of China [50571085, 20773100, 20620130427, 20773135]; National Basic Research Program of China 973 Program [2007CB935603]; Technology Program of Fujian and Xiamen, China [2007H0031, 3502Z20073004]; Chinese Academy of Science