Phased Array with Surface Acoustic Wave (SAWPA) for Screening and Sizing of Surface Defects

Nondestructive inspection of whole structures is important for the safety and reliability. For the inspection of internal defects, ultrasonic testing (UT) with bulk waves has been widely used, whereas such UT cannot inspect surface due to a dead zone. To this end, we proposed a phased array with surface acoustic wave (SAW PA) [1,2] for rapidly inspecting surface defects with a high sensitivity. However, the performance has yet to be fully educed because it was not optimized in terms of the wedge and imaging region. The objective of this study is to improve SAW PA and to demonstrate the wide-range and detailed imaging capabilities for screening and sizing, respectively. The schematic of SAWPA is illustrated in Fig. 1. An array transducer is set on a wedge with a critical angle of Rayleigh wave. Following a delay law, SAWis focused on multiple focal points on the surface, providing an image over the scan area. Note that SAWPA has a capability of a real-time imaging. In this study, the wedge for SAW generation was improved. In the previous study [1], the wedge was made of acrylic resin that is inexpensive and has good workability. It is however relatively attenuative, so that the incident wave was significantly attenuated during the propagation in the wedge. Therefore, it was changed to polystyrene that is less attenuative. The polystyrene has smaller critical angle than acrylic resin, thus also shortening the propagation distance in the wedge. This is useful for both screening and sizing. To show the wide-range imaging capability, a hole specimen (A6063) was imaged with varying the propagation distance of Rayleigh wave. As a result, a sufficient signal-to-noise ratio was obtained even in a far distance of 400 mm (Fig. 2). Subsequently, it was applied to the crack specimen, where the imaging area was set beneath the wedge to attain high resolution and sensitivity, although the region outside the wedge was selected for screening and in Ref. [1]. As a result, the crack was clearly imaged with a high resolution. These results show that the improved SAWPA is useful for both screening and sizing

High Serum Advanced Glycation End Products Are Associated with Decreased Insulin Secretion in Patients with Type 2 Diabetes: A Brief Report

Advanced glycation end products (AGEs) are important in the pathophysiology of type 2 diabetes mellitus (T2DM). They directly cause insulin secretory defects in animal and cell culture models and may promote insulin resistance in nondiabetic subjects. We have developed a highly sensitive liquid chromatography-tandem mass spectrometry method for measuring AGEs in human serum. Here, we use this method to investigate the relationship between AGEs and insulin secretion and resistance in patients with T2DM. Methods. Our study involved 15 participants with T2DM not on medication and 20 nondiabetic healthy participants. We measured the AGE carboxyethyllysine (CEL), carboxymethyllysine (CML), and methyl-glyoxal-hydro-imidazolone (MG-H1). Plasma glucose and insulin were measured in these participants during a meal tolerance test, and the glucose disposal rate was measured during a euglycemic-hyperinsulinemic clamp. Results. CML and CEL levels were significantly higher in T2DM than non-DM participants. CML showed a significant negative correlation with insulin secretion, HOMA-%B, and a significant positive correlation with the insulin sensitivity index in T2DM participants. There was no correlation between any of the AGEs measured and glucose disposal rate. Conclusions. These results suggest that AGE might play a role in the development or prediction of insulin secretory defects in type 2 diabetes

Optineurin regulates osteoblastogenesis through STAT1

A sophisticated and delicate balance between bone resorption by osteoclasts and bone formation by osteoblasts regulates bone metabolism. Optineurin (OPTN) is a gene involved in primary open-angle glaucoma and amyotrophic lateral sclerosis. Although its function has been widely studied in ophthalmology and neurology, recent reports have shown its possible involvement in bone metabolism through negative regulation of osteoclast differentiation. However, little is known about the role of OPTN in osteoblast function. Here, we demonstrated that OPTN controls not only osteoclast but also osteoblast differentiation. Different parameters involved in osteoblastogenesis and osteoclastogenesis were assessed in Optn−/- mice. The results showed that osteoblasts from Optn−/- mice had impaired alkaline phosphatase activity, defective mineralized nodules, and inability to support osteoclast differentiation. Moreover, OPTN could bind to signal transducer and activator of transcription 1 (STAT1) and regulate runt-related transcription factor 2 (RUNX2) nuclear localization by modulating STAT1 levels in osteoblasts. These data suggest that OPTN is involved in bone metabolism not only by regulating osteoclast function but also by regulating osteoblast function by mediating RUNX2 nuclear translocation via STAT1

Rapid and Quantitative Assay of Amyloid-Seeding Activity in Human Brains Affected with Prion Diseases

The infectious agents of the transmissible spongiform encephalopathies are composed of amyloidogenic prion protein, PrPSc. Real-time quaking-induced conversion can amplify very small amounts of PrPSc seeds in tissues/body fluids of patients or animals. Using this in vitro PrP-amyloid amplification assay, we quantitated the seeding activity of affected human brains. End-point assay using serially diluted brain homogenates of sporadic Creutzfeldt-Jakob disease patients demonstrated that 50% seeding dose (SD50) is reached approximately 1010/g brain (values varies 108.79-10.63/g). A genetic case (GSS-P102L) yielded a similar level of seeding activity in an autopsy brain sample. The range of PrPSc concentrations in the samples, determined by dot-blot assay, was 0.6-5.4 μg/g brain; therefore, we estimated that 1 SD50 unit was equivalent to 0.06-0.27 fg of PrPSc. The SD50 values of the affected brains dropped more than three orders of magnitude after autoclaving at 121°C. This new method for quantitation of human prion activity provides a new way to reduce the risk of iatrogenic prion transmission