Eggs of many marine and mammalian species attract sperm by releasing chemoattractants that modify the bending properties of flagella to redirect sperm paths toward the egg. This process, called chemotaxis, is dependent on extracellular Ca(2+). We used stroboscopic fluorescence imaging to measure intracellular Ca(2+) concentration ([Ca(2+)]i) in the flagella of swimming sea urchin sperm. Uncagin...

Mechanical properties of flexible films, for example surface strain of largely bending films, are key to design of stretchable electronic devices, wearable biointegrated devices, and soft microactuators/robots. However, existing methods are mainly based on strain-gauge measurements that require miniaturized array sensors, lead wires, and complicated calibrations. Here we introduce a facile meth...

Using present knowledge of the cell's optical and growth mechanisms, a theoretical bending speed of about 5 degrees min.(-1) is calculated for unilateral irradiation by a single beam of normally incident visible light; this figure is of the magnitude found experimentally. Between beams of light opposed at 180 degrees , the resultant bending speed is given by the difference-to-sum ratio of the l...

PURPOSE Preservative treatments are necessary for disinfection and long term storage when dealing with biological tissue. Freezing is a gold standard but infectious risk can only be eliminated by using chemical fluids that may alter the mechanical properties, depending on their composition. Therefore, we experimentally evaluated the influence of freezing and of two commonly used preservative fl...

Structural aspects of organic molecular films, such as disordering, packing density, molecular bending or tilts, and phase separation, influence electrical properties as well as friction and adhesion. This indicates a correlation between nanomechanical and charge transport properties of molecular films at the molecular scale. In this review, we highlight the recent studies on correlations betwe...

We performed molecular dynamics simulations to study the equilibrium and flow properties of a liquid in a nano-channel with confining surfaces coated with a layer of grafted semiflexible polymers. The coverage spans a wide range of grafting densities from essentially isolated chains to dense brushes. The end-grafted polymers were described by a bead spring model with a harmonic potential to inc...

According to the direct homogenization theory of inhomogeneous material, a single medium homogenization constitutive model of the confined concrete in the steel box-concrete combined member has been established, and model parameters have been determined by the measured data of the bending test. By analyzing the theoretical ultimate strength and overall process curve, the results obtained is con...

In this study, a novel numerical method is proposed for determination of mode-I interlaminar fracture toughness, GIc, in multi-directional (MD) double cantilever beam (DCB) specimens using fracture properties of unidirectional DCB specimens. Two factors, β and Dc are defined to minimize the undesirable effects on strain energy release rate. β describes the difference between maximum and average...

NeP1 binds to the F1 silencer element of the chicken lysozyme gene and, in the presence of TR, v-ERBA or RAR, synergistically represses transcriptional activity. This repression involves a silencing mechanism acting independently of the relative promoter position. Here we show that NeP1 alone can induce a significant directed bend on DNA. The chicken homologue of human NeP1, CTCF, shows identic...

This paper investigates the hygrothermal effects on the failure mechanisms in bending of carbon fibre reinforced polymer (CFRP) composites. Accelerated diffusion testing was carried out by immersion at 50°C constant temperature and 70 bar hydrostatic pressure to study the effects of fresh or sea water diffusion into pre-preg CFRP laminates. Consequently the composite laminates were tested in be...