Experimental Study on Bond-Strengthening Hooks for RC Beams

This paper presents an experimental investigation of bond-strengthening hooks as a new method to increase bond strength along flexural reinforcing bars in reinforced concrete (RC) beams. The proposed method attempts to increase confining stiffness around the flexural bars by placing U-shaped hooks and to prevent premature bond splitting failure. Ten specimens with different numbers and sizes of hooks were prepared to verify the strengthening effectiveness under monotonic four-point loading. The test results indicated that the hooks increased the bond strength along flexural bars although the strengthening effectiveness was limited by the effective number of anchors of hooks Nbe. This limit is determined by the size of the stress-transmitting zones of the concrete around the anchors of the hooks. The bond-strengthening effectiveness of hooks was found to be equivalent to that of conventional internal ties

Experimental Study on Bond-Strengthening Hooks for RC Beams

This paper presents an experimental investigation of bond-strengthening hooks as a new method to increase bond strength along flexural reinforcing bars in reinforced concrete (RC) beams. The proposed method attempts to increase confining stiffness around the flexural bars by placing U-shaped hooks and to prevent premature bond splitting failure. Ten specimens with different numbers and sizes of hooks were prepared to verify the strengthening effectiveness under monotonic four-point loading. The test results indicated that the hooks increased the bond strength along flexural bars although the strengthening effectiveness was limited by the effective number of anchors of hooks Nbe. This limit is determined by the size of the stress-transmitting zones of the concrete around the anchors of the hooks. The bond-strengthening effectiveness of hooks was found to be equivalent to that of conventional internal ties

Bond-Strengthening Hooks for RC Members with 1300MPa-Class Shear-Reinforcing Spirals : Part III: Bond Strengths of Double-Layered Longitudinal Bars and Cut-Off Bars(Building Structures and Materials)

This paper presents an experimental investigation of reinforced concrete (RC) beams with double layered longitudinal bars, bond-strengthening hooks and 1300MPa-class spirals. The hooks made of mild steel increased the bond strength along longitudinal bars. This experiment is aimed at quantification of not only the effectiveness of the spirals and bond-strengthening hooks on the RC members consisting of double layered longitudinal bars but also the influence of cut-off bars in an inner (second) layer. Twelve specimens were prepared and subjected to cyclic shear loads. All the specimens failed because of bond splitting along the longitudinal bars. The hooks, made of mild steel, increased the bond strength along the longitudinal bars. Applying the bond-strengthening hooks was found to improve the shear capacities of the specimens with the cut-off bars. The authors developed a truss mechanism model for members with longitudinal bars in an inner (second) layer. The model showed that the shear strength depends on the span/depth ratio L/D and inner (second) layer bar length L_d

The Met268Pro Mutation of Mouse TRPA1 Changes the Effect of Caffeine from Activation to Suppression

The transient receptor potential A1 channel (TRPA1) is activated by various compounds, including isothiocyanates, menthol, and cinnamaldehyde. The sensitivities of the rodent and human isoforms of TRPA1 to menthol and the cysteine-attacking compound CMP1 differ, and the molecular determinants for these differences have been identified in the 5th transmembrane region (TM5) for menthol and TM6 for CMP1. We recently reported that caffeine activates mouse TRPA1 (mTRPA1) but suppresses human TRPA1 (hTRPA1). Here we aimed to identify the molecular determinant that is responsible for species-specific differences in the response to caffeine by analyzing the functional properties of various chimeras expressed in Xenopus oocytes. We initially found that the region between amino acids 231 and 287, in the distal N-terminal cytoplasmic region of mTRPA1, is critical. In a mutagenesis study of this region, we subsequently observed that introduction of a Met268Pro point mutation into mTRPA1 changed the effect of caffeine from activation to suppression. Because the region including Met-268 is different from other reported ligand-binding sites and from the EF-hand motif, these results suggest that the caffeine response is mediated by a unique mechanism, and confirm the importance of the distal N-terminal region for regulation of TRPA1 channel activity

A novel binding site between the voltage-dependent calcium channel CaV1.2 subunit and CaVβ2 subunit discovered using a new analysis method for protein–protein interactions

Abstract We developed a new method to analyze protein–protein interactions using a dual-inducible prokaryotic expression system. To evaluate protein–protein binding, a chimeric fusion toxin gene was constructed using a DNase-treated short DNA fragment (epitope library) and CcdB, which encodes a DNA topoisomerase II toxin. Protein–protein interactions would affect toxin activity, resulting in colony formation. Using this novel system, we found a new binding site in the voltage-dependent calcium channel α1 subunit (CaV1.2) for the voltage-dependent calcium channel β2 subunit. Prokaryotic expression screening of the β2 subunit using an epitope library of CaV1.2 resulted in two overlapping clones of the C-terminal sequence of CaV1.2. In vitro overlay and immunoprecipitation analyses revealed preferential binding of the C-terminal sequences of CaV1.2 and β2

Outcomes in Newly Diagnosed Atrial Fibrillation and History of Acute Coronary Syndromes: Insights from GARFIELD-AF

BACKGROUND: Many patients with atrial fibrillation have concomitant coronary artery disease with or without acute coronary syndromes and are in need of additional antithrombotic therapy. There are few data on the long-term clinical outcome of atrial fibrillation patients with a history of acute coronary syndrome. This is a 2-year study of atrial fibrillation patients with or without a history of acute coronary syndromes