Efficient DNA strand displacement by a W-shaped nucleoside analogue (WNA-βT) containing an ortho-methyl-substituted phenyl ring

Molecules that can target duplex DNA with sequence selectivity have the potential to be useful tools in genomic research and also as therapeutic agents. Homopurine-homopyrimidine stretches in duplex DNA can be recognized by homopurine or homopyrimidine TFOs (triplex-forming oligonucleotides) through the formation of triplex DNA. We have previously developed bicyclic nucleoside analogues (WNAs) for the formation of stable triplexes in the formation of stable antiparallel triplexes containing a TA or a CG interrupting site. In this study, we investigated the effects on triplex DNA formation of ortho-, meta-, and para-methyl substituent groups on the aromatic ring of the WNA analogue. It was found that the homopurine TFO containing meta- and para-methyl-substituted WNA-βT (mMe-WNA-βT, pMe-WNA-βT) stabilized triplexes containing a TA interrupting site or a GC site, respectively. Interestingly, the ortho-methyl-substituted WNA-βT (oMe-WNA-βT) efficiently promoted DNA strand displacement to form the TFO/pyrimidine duplex. A detailed investigation showed that the duplex was in the antiparallel orientation and that its formation took place prior to triplex formation with the need for a magnesium cation. NOESY measurements indicated a significant difference in the rotation flexibilities of the phenyl rings of WNA-βTs: that is, the conformation of the ortho-methylated phenyl ring was stable in a temperature-independent manner. It was speculated that the initial formation of a ternary complex was followed by strand displacement and then the formation of the TFO/pyrimidine duplex together with the TFO(2)/pyrimidine triplex formation during the early stage, and that the equilibrium shifted to the triplex during the later stage. Although the detailed role is still uncertain, the fixed phenyl ring of oMe-WNA-βT might play a role in the displacement reaction.     

Development of an In-pipe micro mobile robot using peristalsis motion

Currently, many researchers from various fields are engaged in developing machines that move in a tubular cylinder. Many such machines are being developed for industrial purposes, such as for the examination of ruptures at the joints of gas and water pipes and those caused by cracks. Studies specifically focused on applications to the medical field, such as the realization of machines that can travel through the intestines and blood vessels, have also been reported. In this study, we propose a microscopic moving mechanism that can move in 2–3 mm-diameter blood vessels by peristalsis motion with repeated expansion and contraction using hydraulic pressure, particularly using a physiological saline solution as an acting fluid. Peristalsis motion, observed in earthworms and nematodes, induces shape variation and a shift in the center of gravity, causing extensional waves to propagate and thus achieving movement without damage to the vulnerable inner walls of blood vessels. When this moving mechanism is combined with catheters, we can realize an active catheter that can reach a diseased site by itself. In this study, we created a microrobot with pistonlike hydraulic pressure sources outside both its ends. The microrobot can move back and forth as follows. When the piston pumps, the acting fluid is repeatedly injected into and ejected from the driving body, while the microrobot changes the length and width of its rubber body. The development of our microrobot and the results of its evaluation are reported in this paper.     

All-fiber Q-switched operation of thulium-doped silica fiber laser by piezoelectric microbending

We demonstrate an all-fiber Q-switched laser operation in the 2 μm region on the basis of a dynamic periodic microbend and pulsed-pump configuration. A single-mode thulium-doped silica fiber is pumped by 1.6 μm-band laser diodes, and the dynamic loss is introduced in the fiber ring resonator by the periodic microbend that is electrically controlled with a piezoelectric actuator. When the voltage-off period of the piezoelectric actuator is set at 20 μs for the pump power of 120 mW, the output pulse power is measured by 420 mW with a pulse width of 1.3 μs.     

High-velocity impact damage behavior of plain-woven SiC/SiC composites after thermal loading

This study investigates characteristics of foreign-object damage in plain-woven SiC/SiC composites after thermal loading. High-speed impact tests were conducted on virgin specimens, thermally exposed specimens, and thermally shocked specimens, in which the maximum temperature during thermal loading was 600 °C or 1000 °C. An oxide layer was generated on the specimen surface by thermal loading at 1000 °C. Damaged areas on the front and back surfaces induced by particle impact were independent of thermal loading. However, in specimens thermally loaded at 1000 °C, brittle failure, i.e. cone cracking without fiber pull-out, occurred due to oxidation of the fiber/matrix interfaces, and the ballistic limit velocity significantly decreased. Finally, the ballistic limit is predicted using static strength properties, and the effect of thermal loading on impact resistance is discussed.     

Correlation between preoperative mouth opening and surgical outcome after arthroscopic lysis and lavage in patients with disc displacement without reduction

PURPOSE: This study was designed to evaluate the efficacy of arthroscopic lysis and lavage for patients with limited mouth opening. The relationship between preoperative mouth opening and the surgical outcome was determined. METHOD: Fourteen patients with 16 internally deranged joints were treated by arthroscopic lysis and lavage. All had received 10.4 (7 to 19) months of nonsurgical treatment before arthroscopy. The preoperative magnetic resonance images showed anterior disc displacement without reduction in all treated joints. RESULTS: Twelve of the 14 patients (86%) showed good reduction in pain and improved range of jaw movement on average follow-up of 28.5 (13 to 66) months. Two patients showed no improvement after arthroscopy and required open surgical procedures. The preoperative mouth opening of the successful group averaged 29.4 (22 to 35) mm, whereas the two failed cases had 10- and 19-mm openings, respectively (P < .05). CONCLUSION: Persistent limitation of mouth opening of more than 22 mm after nonsurgical treatment has a good prognosis when treated by arthroscopic lysis and lavage. However, those with greater limitation should probably have earlier surgical intervention.     

GaAs Hall-effect devices fabricated by ion-implantation technique

Gallium-arsenide Hall-effect devices were developed by using Se-implanted n layers. A Hall voltage of 85 mV was generated at I = 1 mA and B = 5 kgauss. The imbalance voltage appearing was below 1.4 mV at I = 1 mA and B = 0.This fabrication technique is very promising in the high throughput of GaAs Hall-device production.     

An NDT technique for composite structures using visualized Lamb-wave propagation

This study proposes a non-destructive testing (NDT) technique that visualizes the propagation of ultrasonic waves in solids, including composite laminates. This technique provides a moving diagram of traveling waves through the use of a pulsed laser that scans a test piece. A non-contact scan by the pulsed laser for ultrasound generation with reception at a fixed point enables us to inspect an arbitrarily shaped object and also facilitates easy operation of the measurement system. We applied the proposed technique to the inspection of CFRP laminates and successfully visualized the wave scattering due to impact-induced delamination as well as the propagation of the S₀ and A₀ Lamb modes. We also addressed disbonding detection in a composite skin-stringer structure and concluded that the reliable detection of damage and the advantages of the proposed technique are applicable to inspections of composite structures.     

Color functional images of the cerebral blood flow

Functional gamma imaging, in color, was established for regional cerebral blood flow (rCBF) using 133Xe. During 10 min after intracarotid injection of 133Xe in saline, 60 picture frames of the 133Xe clearance curve for the entire hemisphere were obtained. After nine-point smoothing, the rCBF for each of the 4,096 picture elements was calculated by two methods: the half-time method and the height-over-area method. Both the 133Xe clearance half-times and the calculated CBF values were displayed, using 13 steps of color, as functional CBF images of the brain. Images of peak count and total count were also displayed on the same frame of the color television. Forty-six studies, performed on 37 patients with various cerebral disorders, were divided into two types: diffuse and focal. In the diffuse type, a decrease in CBF was noted in cases of normal-pressure hydrocephalus; successful ventriculoperitoneal shunt operations were followed by recovery of CBF. Occlusion of the middle cerebral artery showed up as a wedge-shaped area of decreased CBF, even when the conventional brain scan looked normal. Increased perfusion to a tumor was frequently associated with decreased CBF in the rest of the lateral hemisphere; such a decrease could be improved by surgical removal of the tumor.     

Cytotoxic lymphocytes in the peripheral blood of patients with B cell lymphomas

In order to analyze systemic immune surveillance in patients with B cell non-Hodgkin's lymphomas (B-NHL), we investigated circulating lymphocytes using two-color flow cytometry. The proportions of CD3-CD56+ natural killer (NK) cells and CD8++(bright) S6F1++ killer-effector T cells corresponding to activated cytotoxic T lymphocytes (aCTL) were studied in the peripheral blood of 26 patients with indolent lymphoma (IL) and 24 with aggressive lymphoma (AL). The AL patients with both limited disease and advanced disease had an increased proportion of NK cells. However, this feature was not evident in IL patients with either limited or advanced disease. In contrast, an increased proportion of aCTL was observed only in IL patients with advanced disease. These findings indicate that IL may differ from AL in terms of immune surveillance against neoplastic B cells.     

A modified method of cardiac functional analysis for ECG gated SPECT: study of functional G-maps

To evaluate the cardiac function accurately using ECG gated SPECT images, we performed a modified method of cardiac functional analysis (Functional G-maps). One hour after the intravenous injection of 1,110 MBq of 99mTc-tetrofosmin, gated SPECT data was acquired dividing a cardiac cycle into 12 frames. Every short-axis images were usually reconstructed using first 11 of 12 frames. The reconstruction of these images was repeated performing slice thickness correction. Because the apex-to-base length is different at any frame during a cardiac cycle, 10 slices of short-axis images were obtained with the same thickness for each frame. Subsequently each short-axis image was divided by 40 radii, and the time activity curve was generated from the total counts included in each segment plus both neighboring segments. Afterwards the curve fitting was performed using the second reverse Fourier function. From fitted curves and their differentials, we estimated a variety of parameters including Max (End-systolic count), Min (End-diastolic count), %CI (Percent count increase), Uptake, PCR (Peak contraction rate), PDR (Peak distention rate) and CT (Contraction time). In 5 normal subjects, %Max was greater in the anterior and septal regions, whereas %Min was greater in the apex and lateral regions. %CI and %PCR were similarly greater in the septal, anterior and inferior regions. On the other hand, %PDR in the lateral or inferior region was lower than the values in the other regions. In conclusion, this modified method is expected to be useful for accurate assessment of regional cardiac function and myocardial perfusion.