Search

Akihiro Kuwahata,1,* Muneer Ahmed,2,* Kohei Saeki,3 Shinichi Chikaki,1 Miki Kaneko,1 Wenqi Qiu,1 Zonghao Xin,1 Shinji Yamaguchi,3 Akiko Kaneko,1 Michael Douek,2 Moriaki Kusakabe,3,4 Masaki Sekino1 1Department of Electrical Engineering and Information Systems, Graduate School of Engineering, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo, Japan; 2Division of Cancer Studies, King’s College London, Guy’s Hospital Campus, Great Maze Pond, London, UK; 3Graduate School of Agriculture and Life Sciences, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo, Japan; 4Matrix Cell Research Institute Inc., Ibaraki, Japan *These authors contributed equally to this work Background: Sentinel node biopsy using radioisotope and blue dye remains a gold standard for axillary staging in breast cancer patients with low axillary burden. However, limitations in the use of radioisotopes have resulted in emergence of novel techniques. This is the first in vivo study to assess the feasibility of combining the two most common novel techniques of using a magnetic tracer and indocyanine green (ICG) fluorescence.Materials and methods: A total of 48 mice were divided into eight groups. Groups 1 and 2, the co-localization groups, received an injection of magnetic tracers (Resovist® and Sienna+®, respectively) and ICG fluorescence; distilled water was used as the solvent of ICG. Groups 3 and 4, the diluted injection groups, received an injection of magnetic tracers (Resovist and Sienna+, respectively) and saline for dilution. Groups 5, 6, and 7, the control groups, received magnetic tracer (Resovist, Sienna+) and ICG alone, respectively. Fluorescent intensity assessment and iron quantification of excised popliteal lymph nodes were performed. Group 1', a co-localization group, received an injection of magnetic tracers (Resovist) and ICG' fluorescence: saline was used as the solvent for ICG.Results: Lymphatic uptake of all tracers was confined to the popliteal nodes only, with co-localization confirmed in all cases and no significant difference in fluorescent intensity or iron content of ex vivo nodes between the groups (except for Group 1'). There was no impact of dilution on the iron content in the diluted Sienna+ group, but it significantly enhanced Resovist uptake (P=0.005). In addition, there was a significant difference in iron content (P=0.003) in Group 1'.Conclusion: The combination of a magnetic tracer (Resovist or Sienna+) and ICG fluorescence is feasible for sentinel node biopsy and will potentially allow for precise transcutaneous node identification, in addition to accurate intraoperative assessment. This radioisotope-free “combined technique” warrants further assessment within a clinical trial. Keywords: sentinel node biopsy, combined technique, fluorescence dye, magnetic nanoparticles, dilutional effect

To perform transcranial magnetic stimulation therapy at home, a stimulation coil that is robust against misalignment must be employed. A dome-shaped coil is one such coil; however, it has the disadvantage that the induced electric field is smaller than that of the conventional figure-8 coil. In this study, we developed a double D-shaped coil with a horizontal return path to suppress the influence of the return current, while reducing the inductance of the coil. After optimizing geometric parameters of the double D-shaped coil through numerical simulations, we fabricated the coil and evaluated its performance on healthy subjects. It was confirmed that the developed coil was found to tolerate a wider range of positioning errors than the figure-8 coil when stimulating the motor cortex. [ABSTRACT FROM AUTHOR]

We present a novel method for estimating the magnetic field that can generate the desired magnetic force to move magnetic nanoparticles in a region of interest. The magnetic field is expanded using vector spherical harmonics, and the optimal multipole moments are estimated. The multipole moments are included in quadratic form because the magnetic force is defined as the product of the magnetic field and its gradient. We transform the system of quadratic equations into a rank-one-matrix estimation problem to construct a convex numerical algorithm based on a well-established proximal operation. The proposed method was validated using numerical simulations and can be used to design magnetic force patterns that cannot be generated using a simple coil pair. [ABSTRACT FROM AUTHOR]

The finite-difference method is used for solving the diffusion equation of nuclear magnetization in discrete space and time. The purpose of this study was to obtain the time step [DELTA]t and the spatial step [DELTA]x, which minimize computational errors in simulation. We evaluated the difference between a discrete solution and an explicit solution that had been derived from the magnetization diffusion equation. The results revealed the existence of [DELTA]x, which minimizes computational errors. The spatial step [DELTA]x and computational errors increased as the time step [DELTA]t increased. The results should be useful for efficiently carrying out diffusion simulations within given time limitations for computation. Index Terms--Computational errors, diffusion, finite difference methods, magnetic resonance imaging, water molecules.

The present study demonstrated the measurement of [Na.sub.e]/[Na.sub.i] in sciatic nerves by [sup.23]Na-MRS using [sup.23]Na frequency shift agent [Na.sup.4] HTmDOTP. Sciatic nerves from bull frogs were submerged into the 5 mM TmDOTP solution for 12 h before acquisition. MRS was performed on a Varian 4.7-T magnetic resonance spectrometer. To obtain the shift of [Na.sub.e]/[Na.sub.i] resonance, [sup.23]Na spectra were acquired from the whole sample with TR 50 ms and 800 averages. [Na.sub.e] and [Na.sub.i] signals were detected clearly in the spectra of TmDOTP solution-immerged nerve. Then, for evaluation of nerves viability, action potential of TmDOTP solution-immerged nerve was examined. TmDOTP had no effects on the generation of action potential. An increase of [Na.sub.e] signal/[Na.sub.i] signal was observed during the electrical stimulation, suggesting that this result reflected the direct changes in sodium ions permeability during the nerves excitation. Index Terms--Magnetic resonance spectroscopy, nerve excitation, sodium ion.

Repetitive pulsed magnetic stimulation (RPMS) is the use of pulsed magnetic fields to induce electric fields in the tissues by electromagnetic induction without the need for surgery or external electrodes. In the present study, the combination effect of RPMS and an anticancer agent was examined on human chronic myelogenous leukemia-derived cell line TCC-S using molecular target drug (selective tyrosine kinase inhibitor) imatinib mesylate (imatinib). The stimulus conditions were determined as follows: 0.1, 0.25, and 0.5 T, 25 pulses/s, 1000, 3000, and 6000 pulses/day. TCC-S cells were cultured with 100 nM imatinib and exposed to RPMS at 1 h, 12 h, 24 h, 36 h, 48 h, and 56 h after drug treatment. The significant combination effects of RPMS and imatinib occurred by the stimulus intensity and pulse dose depended manner. To clarify the effects of RPMS on human normal lymphocytes, PBMCs were also exposed to RPMS with or without imatinib. RPMS had no effect on the viability of PBMCs. These results indicate that RPMS possibly improve the effectiveness of anticancer agents. Index Terms--Anticancer agent, leukemia cells, repetitive pulsed magnetic stimulation.

We investigate the effects of repetitive magnetic stimulation on tumors and immune functions. A circular coil (inner diameter = 15 mm, outer diameter = 75 mm) is used in the experiments. Stimulus conditions are: peak magnetic field = 0.25 T (at the center of the coil), frequency = 25 pulses/s, 1000 pulses/sample/day, and magnetically induced eddy currents in mice = 0.79-1.54 A/[m.sup.2]]. The sham group mice are placed in the same holders and exposed to the same noise produced during the stimulation. The tumor growth study shows a significant tumor weight decrease due to the application of magnetic stimulation (54% versus the sham group). An immunological assay is also performed to examine the effects of the magnetic stimulation on immune functions. An in vivo study, TNF-[alpha] and IL-2 productions in the spleen are measured after exposure of the magnetic stimulation three or seven times. TNF-[alpha] production significantly increases in the stimulated group (146%-164% versus the sham group). In an in vitro study, isolated spleen cells (lymphocytes) are exposed to the magnetic stimulation (25 pulses/s, 1000 pulses/sample, and eddy currents: 2.36-2.90 A/[m.sup.2]) and a proliferation assay is performed. The poliferation activity of the lymphocytes is up-regulated in the exposed samples. These results indicate that the immune functions might be activated by repetitive magnetic stimulation exposure, resulting in a tumor weight decrease. Index Terms--Eddy currents, immune system, pulsed magnetic stimulation.

A method is described for noninvasively evaluating the permeability of the cell membrane in the rat brain by using diffusion magnetic resonance imaging (MRI). This method is useful for noninvasively estimating the cell membrane permeability of biological tissues and it can be easily applied to human tissues.

Current distribution image of the rat brain using diffusion weighted magnetic resonance imaging is discussed. By comparing subtraction MRI maps of ADC of rat brain tissue, we showed that applied external electrical currents increase the ADC of rat brain tissue.

This study clarifies the location, size and age at the onset of metamorphosis in Japanese eels Anguilla japonica through oceanic surveys, rearing experiments and analyses of the morphology and otoliths of leptocephali and glass eels. Twenty‐eight metamorphosing leptocephali were collected in the mesoscale eddy region to the east of Taiwan during research expeditions in 2004. Rearing experiments showed that the total length (LT) of leptocephali decreased by an average of 12·5% during metamorphosis and 13·9% during the 2–12 h after death. Thus, the mean back‐calculated LT at the onset of metamorphosis for 630 glass eels from Taiwan and Japan was estimated at 67·8 ± 2·7 mm (mean ± S.D.). The estimated mean ante‐mortem size of the fully grown pre‐metamorphic leptocephali collected in 2004 was 64·6 ± 3·4 mm, which was consistent with the LT estimate for glass eels. Otolith analysis showed that the mean age at the onset of metamorphosis was 137 ± 15 days and indicated that Japanese eels may have a recruitment route through the mesoscale eddies to the east of Taiwan in addition to the direct transfer route from the North Equatorial Current to the Kuroshio Current. [ABSTRACT FROM AUTHOR]

Background The standard for sentinel lymph node biopsy ( SLNB), the dual technique (radiolabelled tracer and blue dye), has several drawbacks. A novel magnetic technique without these drawbacks has been evaluated in a number of clinical trials. It uses a magnetic tracer and a handheld magnetometer to identify and excise sentinel lymph nodes. A systematic review and meta-analysis was performed to assess the performance and utility of the magnetic in comparison to the standard technique. Methods MEDLINE, PubMed, Embase and the Cochrane online literature databases were used to identify all original articles evaluating the magnetic technique for SLNB published up to April 2016. Studies were included if they were prospectively conducted clinical trials comparing the magnetic with the standard technique for SLNB in patients with breast cancer. Results Seven studies were included. The magnetic technique was non-inferior to the standard technique ( z = 3·87, P < 0·001), at a 2 per cent non-inferiority margin. The mean identification rates for the standard and magnetic techniques were 96·8 (range 94·2-99·0) and 97·1 (94·4-98·0) per cent respectively (risk difference ( RD) 0·00, 95 per cent c.i. -0·01 to 0·01; P = 0·690). The total lymph node retrieval was significantly higher with the magnetic compared with the standard technique: 2113 (1·9 per patient) versus 2000 (1·8 per patient) ( RD 0·05, 0·03 to 0·06; P = 0·003). False-negative rates were 10·9 (range 6-22) per cent for the standard technique and 8·4 (2-22) per cent for the magnetic technique ( RD 0·03, 0·00 to 0·06; P = 0·551). The mean discordance rate was 3·9 (range 1·7-6·9) per cent. Conclusion The magnetic technique for SLNB is non-inferior to the standard technique, with a high identification rate but with a significantly higher lymph node retrieval rate. [ABSTRACT FROM AUTHOR]

Occupational exposure to static magnetic fields (SMF) is a concern in relation to magnetic resonance imaging (MRI) system operators. Bodily movements inside the stray field around an MRI system induce an electric current inside the body, and this magnetically induced current can cause temporary sensational changes. Although self-motivated motion control near MRI equipment is recommended in order to prevent these effects, a feasible and safe working procedure is required from a health and safety management viewpoint. In this paper, a procedure involving a restricted access area set at a distance of 30 cm from the end of a 3 T MRI system is compared with a protocol in which self-motivated motion control was used (as recommended by the International Commission on Non-Ionizing Protection guidelines). The effects of this safe working procedure on occupational SMF exposure levels and worker performance were evaluated using Hall sensors and a motion capture system. Subjects performed the protocol for head MRI examination both with and without the proposed safe working procedure. The values for maximum field exposure (peak B) were reduced for all subjects using the safe working procedure. The average peak B also decreased by approximately 26%, compared with the results obtained without any restrictions (conventional protocol) ( $p<0.01$ , $t$ -test). Motion analysis of the subjects indicated that the minimum approach distance to the MRI equipment increased due to the adoption of the restricted access area ( $p<0.05$ , $t$ -test), while slight changes were also observed in sojourn time and the differences of the position along the $z$ -axis ( $\Delta z$ , $p<0.05$ , $t$ -test). However, there were no significant differences in the parameters more closely related to worker performance (e.g., distance moved and velocity) when using the protocols with or without the safe working procedure. These results suggest that this simple safe working procedure may be applied to MRI system operation in order to reduce occupational SMF exposure, without noticeable changes in worker performance. [ABSTRACT FROM AUTHOR]

Tri- and tetra-motif repeat microsatellite marker loci were developed for the white-spotted charr Salvelinus leucomaenis. The 454 pyrosequencing was used to discover repeat arrays, and eight microsatellite-primer sets, available for the estimation of polymorphisms, were identified. The number of alleles in a wild population ranged from two to four and the observed and expected heterozygosities were 0·180-0·600 and 0·188-0·599, respectively. [ABSTRACT FROM AUTHOR]

The article presents a study that developed microsatellite markers to monitor the genetic population diversity of the white-streaked grouper Epinephelus ongus. The study's findings reveal 18 polymorphic microsatellites markers in E. ongus with 2-16 allelles and differing estimates of observed and expected heterozygosity. The Hardy-Weinberg equilibrium (HWE) of markers and linkage disequlibrium (LD) between markers were also examined.

Abstract: We studied the magnetization characteristics of the arrayed and stacked bulk superconductors. The bulks were made of GdBaCuO superconductor. Two-dimensional magnetic flux density distributions over bulks were measured after 2.0 T magnetic fields cooling at 77K. The current densities in the bulks were estimated 108 A/m2 order at 77K and the field cooling conditions. The experimental results showed the proposed structure can obtain larger trapped flux area than that of a single bulk. [Copyright &y& Elsevier]

Various techniques have been described for blind bedside placement of a post-pyloric feeding tube. However, there is no universal method and the technique depends on the local institutional resources and expertise. The purpose of this study was to evaluate a simple new technique for the bedside placement of a post-pyloric feeding tube in an intensive care unit using palpation to confirm tube position. We studied 47 consecutive ventilated patients (mean body mass index 22.4 ± 4.2 kg/m(2)) requiring enteral tube feeding for nutritional support. We monitored the maximum intensity point of injected air 'bubbling' by palpation and estimated tube position. We monitored the movement of the maximum intensity point from the left upper quadrant to the right upper quadrant. If the maximum intensity point on the right upper quadrant diminished or weakened, we considered the tube had proceeded beyond the pylorus. By palpation, we could feel the bubbling of the injected air in all patients, but four patients were excluded because of failure to complete the protocol. The overall success rate including the four excluded cases was 85.1% (40/47) on the first attempt and 91.5% (43/47) when we included the second attempt. The median time for 40 successful tube placements on the first attempt was 10 (7 to 23) minutes. Our new palpation technique can successfully detect the position of a feeding tube in the stomach and help guide the tube to the correct location in the post-pyloric portion of the stomach in lean critically ill patients. [ABSTRACT FROM AUTHOR]

Transverse flux enhanced type superconducting synchronous machines have been studied for large-capacity wind power generation. The generators have multiple circular superconducting field coils in the rotor and copper armature windings in the stator. A parametric design study and electromagnetic characteristic analysis of the superconducting wind turbine generators (WTGs) have been carried out. The target output is 10 MW for a rotational speed of 10 rpm, and the diameter of the whole coil system is 5 m. Superconducting technology is quite effective for compact and lightweight design of large power capacity, low-speed and high torque generators. Armature and field coil dimensions and the number of poles are key parameters in the design study. FEM analysis was carried out to obtain magnetic flux density, magnetic flux linkage, induced voltage, fundamental generator characteristics, etc. Required superconducting wire length was also estimated. [ABSTRACT FROM AUTHOR]

The present study was conducted to investigate whether typical isoprenyl compounds (TICs) can control liposomal fusion reactions through changes in the physical properties of membranes. The fusion capabilities of TIC-incorporated liposomes were characterized by measuring the 13C spin-lattice relaxation times (13CT1) and the gel permeation chromatogram (GPC) patterns. The 13CT1 relaxivities of some of these TlC-liposomes were remarkably enhanced at 27degC. The highest 13CT1 value obtained was for the beta-carotene-liposome, which ruptured, and was attributed to the highest membrane fusion reactivity. The other TIC-liposomes incorporated with alpha-tocopherol, canthax- nnlhin, or coenzyme Q10 also induced significant fusion and did not rupture in comparison with the beta-carotene-liposome. These results show that the incorporations of TICs into lipid bilayers are useful to control liposomal nanocarriers for suitable membrane packing and advantageous phase separation, which could affect membrane-related processes. [ABSTRACT FROM PUBLISHER]

Focuses on seawater desalination facilities by reverse osmosis membranes in the world. High-efficiency seawater desalination technology in Japan with improved recovery ratio of fresh water; Spiral wound module; Hollow fiber type reverse osmosis module; Resolution of the problem on meeting Japanese drinking water quality standards.

The present study demonstrated the measurement of Nae/Nai in sciatic nerves by 23Na-MRS using 23Na frequency shift agent Na4 HTmDOTP. Sciatic nerves from bull frogs were submerged into the 5 mM TmDOTP solution for 12 h before acquisition. MRS was performed on a Varian 4.7-T magnetic resonance spectrometer. To obtain the shift of Nae/Nai resonance, 23N spectra were acquired from the whole sample with TR 50 ms and 800 averages. Nae and Nai signals were detected clearly in the spectra of TmDOTP solution-immerged nerve. Then, for evaluation of nerves viability, action potential of TmDOTP solution-immerged nerve was examined. TmDOTP had no effects on the generation of action potential. An increase of Nae signal/Nai. signal was observed during the electrical stimulation, suggesting that this result reflected the direct changes in sodium ions permeability during the nerves excitation. [ABSTRACT FROM AUTHOR]

The outbreak of paralytic shellfish poisoning caused by the toxic dinoflagellate Alexandrium catenella (Dinophyceae) is a worldwide concern from the economic and food hygiene point of view. To assess the dispersal mechanism, a population genetic study using highly polymorphic genetic markers is one of the crucial approaches. We isolated 12 polymorphic microsatellites from this species. These loci provide one class of highly variable genetic marker as the number of alleles ranged from three to 12 and the estimate of gene diversity was from 0.248 to 0.897 across the 12 microsatellites; we consider that these loci have a potential to detail the genetic structure and gene flow among A. catenella populations. [ABSTRACT FROM AUTHOR]

We investigate the effects of repetitive magnetic stimulation on tumors and immune functions. A circular coil (inner diameter = 15 mm, outer diameter = 75 mm) is used in the experiments. Stimulus conditions are: peak magnetic field = 0.25 T (at the center of the coil), frequency = 25 pulses/s, 1000 pulses/sample/day, and magnetically induced eddy currents in mice = 0.79-1.54 A/m2. The sham group mice are placed in the same holders and exposed to the same noise produced during the stimulation. The tumor growth study shows a significant tumor weight decrease due to the application of magnetic stimulation (54% versus the sham group). An immunological assay is also performed to examine the effects of the magnetic stimulation on immune functions. An in vivo study, TNF-α and IL-2 productions in the spleen are measured after exposure of the magnetic stimulation three or seven times. TNF-α production significantly increases in the stimulated group (146%-164% versus the sham group). In an in vitro study, isolated spleen cells (lymphocytes) are exposed to the magnetic stimulation (25 pulses/s, 1000 pulses/sample, and eddy currents: 2.36-2.90 A/m2) and a proliferation assay is performed. The poliferation activity of the lymphocytes is up-regulated in the exposed samples. These results indicate that the immune functions might be activated by repetitive magnetic stimulation exposure, resulting in a tumor weight decrease. [ABSTRACT FROM AUTHOR]

Five novel microsatellite loci were isolated from Pacific abalone Haliotis discus discus, and the polymorphisms were examined to estimate genetic varaiability. The genetic variabilities varied depending on the locus: the number of alleles ranged from 3 to 10, and the observed and expected hetrozygosity ranged from 0.17 to 0.80, and 0.20 to 0.89, respectively. Two loci showed significant Hardy-Weinberg disequilibrium at the 0.01 < P < 0.05 levels. The high variabilities revealed in this study were evidently higher than that observed in allozyme loci, suggesting that these microsatellites should prove useful for various genetic investigations. [ABSTRACT FROM AUTHOR]

Characterizes the microsatellite DNA loci in Japanese flounder Paralichthys olivaceus. Genetic diversity observations; Genetic structure; Levels of heterozygosities; Genetic polymorphisms identified.

Characterizes the microsatellites in the rockfish Sebastes thompsoni. Detection of repeat microsatellites; Length of microsatellite repeats; Heterozygosity; Genetic polymorphism.