Strong and Flexible Braiding Pattern of Carbon Nanotubes for Composites: Stiff and Robust Structure Active in Composite Materials.

Carbon nanotubes (CNTs) exhibit high strength, Young's modulus, and flexibility and serve as an ideal reinforcement for composite materials. Owing to their toughness against bending and/or twisting, they are typically used as fabric composites. The conventional multiaxial braiding method lacks tension and resultant strength in the thickness direction. Some braiding patterns are proposed; however, they may have shortcomings in flexibility. Thus, this study proposed three types of braiding pattern for fabrics based on natural products such as spider net and honeycomb, in accordance with thickness-direction strength. The spider-net-based structure included wefts with spaces in the center with overlapping warps. At both sides, the warps crossed and contacted the wefts to impart solidness to the structure and enhance its strength as well as flexural stability. In addition, box-type wefts were proposed by unifying the weft and warps into boxes, which enhanced the stability and flexibility of the framework. Finally, we proposed a structure based on rectangular and hexagonal shapes mimicking the honeycomb. Moreover, finite element calculations were performed to investigate the mechanisms through which the proposed structures garnered strength and deformation ability. The average stress in fabrics becomes smaller than half (43%) when four edges are restrained and sliding is inserted. Under three-dimensional forces, our proposed structures underwent mechanisms of wrapping, warping, sliding and doubling, and partial locking to demonstrate their enhanced mechanical properties. Furthermore, we proposed a hierarchical structure specialized for CNTs, which could facilitate applications in structural components of satellites, wind turbines, and ships. The hierarchical structure utilizing discontinuity and sliding benefits the usage for practical mechanical systems.

A novel n-type semiconducting biomaterial.

There has been no research conducted thus far on the semiconducting behaviour of biomaterials. In this study, we present an n-type semiconducting biomaterial composed of amorphous kenaf cellulose fibre (AKCF) paper with a voltage-controlled N-type negative resistance. The AKCF generates an alternating-current wave with a frequency of 40.6 MHz from a direct-current voltage source at its threshold voltage (electric field of 5.26 kV/m), which is accompanied by a switching effect with a four-order resistance change at 293 K. This effect is attributed to the voltage-induced occurrence of strong field domains (electric double layers) at the cathode and depletion at the anode of the AKCF device. The proposed AKCF material presents considerable potential for applications in flexible/paper electronic devices such as high frequency power sources and switching effect devices.

Effect of nitric oxide synthase inhibitor on increase in nasal mucosal blood flow induced by sensory and parasympathetic nerve stimulation in rats.

OBJECTIVES: Neural control of nasal blood flow (NBF) has not been systematically investigated. The aim of the present study was to evaluate the effect of electrical stimulation of both sensory and parasympathetic nerves innervating the nasal mucosal arteries on NBF in rats. METHODS: In anesthetized rats, nasociliary (sensory) nerves and postganglionic (parasympathetic) nerves derived from the right sphenopalatine ganglion were electrically stimulated. We measured NBF with a laser-Doppler flowmeter. RESULTS: The nerve stimulation increased NBF on both sides and increased the mean arterial blood pressure. The increase in NBF was larger on the ipsilateral side than on the contralateral side. Hexamethonium bromide, a ganglion blocker, abolished the stimulation-induced pressure effect and the increase in NBF on the contralateral side, but did not abolish the increase in NBF on the ipsilateral side. The remaining increase in NBF was abolished by N(G)-nitro-L-arginine, a nitric oxide synthase inhibitor. Histochemical analysis with nicotinamide adenine dinucleotide phosphate-diaphorase showed neuronal nitric oxide synthase-containing nerves that innervate nasal mucosal arteries. CONCLUSIONS: Nitric oxide released from parasympathetic nitrergic nerves may contribute to an increase in NBF in rats. The afferent impulses induced by sensory nerve stimulation may lead to an increase in mean arterial blood pressure that is partly responsible for the increase in NBF.

True aneurysm of the facial artery.

True aneurysm of the facial artery is extremely rare. We describe a case of true facial aneurysm of the submandibular lesion in a 73-years-old man. A color Doppler ultrasonography and computed tomography (CT) revealed a 2.1 cm x 1.5 cm aneurysm with turbulent arterial flow and some thrombus inside the lumen. At the operation, the aneurysm was excised and proximal and distal ends of the facial artery were ligated. The histopathologic examination confirmed a true aneurysm of the facial artery with degenerative changes of the wall and some thrombus in the lumen. The postoperative course was uneventful, and no recurrence has been noted in more than 1-year follow-up.

Cortical and subcortical activation with monaural monosyllabic stimulation by functional MRI.

Few reports have characterized auditory processing in monaural stimulation, which is important to the understanding of auditory brain activity in subjects with hearing loss. We therefore measured regional brain activity in response to monaural stimulation of 95 dB SPL monosyllables using functional magnetic resonance imaging (fMRI) in subjects with normal hearing and five with unilateral deafness as controls for 'cross-hearing'. Images were analyzed by statistical parametric mapping software. In subjects without hearing loss, the stimuli elicited cortical activation in the primary auditory (BA 41) and auditory association regions (BA 42, 22), particularly contralaterally where extent of activation was approximately 2.5 times the ipsilateral extent. All patients with profound unilateral deafness showed no statistically apparent response in the primary auditory and auditory association regions, ruling out an important influence from cross-hearing. We found fMRI to be a useful technique for analysis of auditory processing that should be applicable to patients with various hearing abnormalities.