Magnetic Field Effect on the Cathodic Potential Oscillation of Zinc Electrode in Alkaline Solution

The magnetic field effect (0?C0.47?T) on cathodic potential oscillation of a zinc cathode in an alkaline solution was studied. By applying a magnetic field, the oscillation interval increased. The oscillation was quenched at 0.47?T. In situ bore-scope observation of the cathode during electrolysis in magnetic fields revealed that the solution convection induced by the Lorentz force causes the observed effect.     

Valve-based microfluidic compression platform: single axon injury and regrowth

We describe a novel valve-based microfluidic axon injury micro-compression (AIM) platform that enables focal and graded compression of micron-scale segments of single central nervous system (CNS) axons. The device utilizes independently controlled "push-down" injury pads that descend upon pressure application and contact underlying axonal processes. Regulated compressed gas is input into the AIM system and pressure levels are modulated to specify the level of injury. Finite element modeling (FEM) is used to quantitatively characterize device performance and parameterize the extent of axonal injury by estimating the forces applied between the injury pad and glass substrate. In doing so, injuries are normalized across experiments to overcome small variations in device geometry. The AIM platform permits, for the first time, observation of axon deformation prior to, during, and immediately after focal mechanical injury. Single axons acutely compressed (~5 s) under varying compressive loads (0-250 kPa) were observed through phase time-lapse microscopy for up to 12 h post injury. Under mild injury conditions (< 55 kPa) ~73% of axons continued to grow, while at moderate (55-95 kPa) levels of injury, the number of growing axons dramatically reduced to 8%. At severe levels of injury (> 95 kPa), virtually all axons were instantaneously transected and nearly half (~46%) of these axons were able to regrow within the imaging period in the absence of exogenous stimulating factors.     

Magnetic field effect on chemical wave propagation from the Belousov-Zhabotinsky reaction

Effects of magnetic field (maximum field, 4 and 93 T(2) m(-1)) on the propagation speed of a chemical wavefront from the Belousov-Zhabotinsky reaction were studied in a thin glass tube. The downward and upward speed and the horizontal one are, respectively affected significantly by vertical and horizontal magnetic fields. Observations of the wavefront shape in magnetic fields showed that the magnetic force-induced convection causes the observed effects.     

Chemical Modification of Saccharomycopsis fibuligera R64 α-Amylase to Improve its Stability Against Thermal, Chelator, and Proteolytic Inactivation

α-Amylase catalyzes hydrolysis of starch to oligosaccharides, which are further degraded to simple sugars. The enzyme has been widely used in food and textile industries and recently, in generation of renewable energy. An α-amylase from yeast Saccharomycopsis fibuligera R64 (Sfamy) is active at 50 °C and capable of degrading raw starch, making it attractive for the aforementioned applications. To improve its characteristics as well as to provide information for structural study ab initio, the enzyme was chemically modified by acid anhydrides (nonpolar groups), glyoxylic acid (GA) (polar group), dimethyl adipimidate (DMA) (cross-linking), and polyethylene glycol (PEG) (hydrophilization). Introduction of nonpolar groups increased enzyme stability up to 18 times, while modification by a cross-linking agent resulted in protection of the calcium ion, which is essential for enzyme activity and integrity. The hydrophilization with PEG resulted in protection against tryptic digestion. The chemical modification of Sfamy by various modifiers has thereby resulted in improvement of its characteristics and provided systematic information beneficial for structural study of the enzyme. An in silico structural study of the enzyme improved the interpretation of the results.