168 research outputs found

    Half-Metallic Heusler Alloy/GaN Heterostructure for Semiconductor Spintronics Devices

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    Because spin-orbit coupling in wurtzite semiconductors is relatively weak compared with that in zincblende ones, the III-nitride semiconductor GaN is a promising material for high-performance optical semiconductor spintronic devices such as spin lasers. For the purpose of reducing the operating power of spin lasers, it is necessary to demonstrate highly efficient electrical spin injection from a ferromagnetic material into GaN with a low-resistance contact. Here, an epitaxial half-metallic Heusler alloy Co2FeAlxSi1−x(CFAS)/GaN heterostructure is developed by inserting an ultrathin Co layer between the CFAS and GaN. The CFAS/n+-GaN heterojunctions clearly show tunnel conduction with very small rectification and a low resistance-area product of ≈3.8 kΩµm2, which is several orders of magnitude smaller than those reported in previous work, at room temperature. Nonlocal spin signals and a Hanle effect curve are observed at low temperatures using lateral spin-valve devices with the CFAS/n+-GaN contacts, suggesting pure spin current transport in bulk GaN. The spin transport is observed at temperatures as high as room temperature, with a high spin polarization of 0.2 at a low bias voltage less than 2.0 V. This study is expected to open a path to GaN-based spintronic devices with highly spin-polarized and low-resistance contacts.Yamada S., Kato M., Ichikawa S., et al. Half-Metallic Heusler Alloy/GaN Heterostructure for Semiconductor Spintronics Devices. Advanced Electronic Materials 9, 2300045 (2023); https://doi.org/10.1002/aelm.202300045

    Measurement and Analysis of Electromyography for Sequential Mastication

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     In the palatability of food, texture is a major factor of food quality. The physical shear force value of meat has been measured. However, quantitative relationship and characterization between shear force value and tenderness as a sensory perception has not been clear. Therefore, a computer system was developed to analyze and to measure the electromyography (EMG) for mastication.  The integral EMG values were almost constant by sequential mastication up to five times. The average of integral EMG values were 63.6 mV with tender meat of pork fillet and 153.8 mV with firm meat of beef round, giving a ratio of 2.4 times. The shear force values of similar samples were 2,300 g and 8,300 g each, and the ratio was 3.6 times. Sensory texture of the subjective feeling was 3ン4 times that corresponded with the shear force value. The integral EMG value could be thought to compress the amount of texture sense.  The integral EMG varied greatly in food, and showed lower value in order of boiled fish surimi, steamed fish paste, pork sausage, konnyaku (devil’s tongue), pork fillet, beef loin, pork ham portion, roast beef, pork loin and beef round. Generally this order reflected the sensory texture of chewing. The deviation of the integral EMG value was smaller than expected, so it has a definite possibility for practical use

    Gremlin Enhances the Determined Path to Cardiomyogenesis

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    BACKGROUND: The critical event in heart formation is commitment of mesodermal cells to a cardiomyogenic fate, and cardiac fate determination is regulated by a series of cytokines. Bone morphogenetic proteins (BMPs) and fibroblast growth factors have been shown to be involved in this process, however additional factors needs to be identified for the fate determination, especially at the early stage of cardiomyogenic development. METHODOLOGY/PRINCIPAL FINDINGS: Global gene expression analysis using a series of human cells with a cardiomyogenic potential suggested Gremlin (Grem1) is a candidate gene responsible for in vitro cardiomyogenic differentiation. Grem1, a known BMP antagonist, enhanced DMSO-induced cardiomyogenesis of P19CL6 embryonal carcinoma cells (CL6 cells) 10-35 fold in an area of beating differentiated cardiomyocytes. The Grem1 action was most effective at the early differentiation stage when CL6 cells were destined to cardiomyogenesis, and was mediated through inhibition of BMP2. Furthermore, BMP2 inhibited Wnt/beta-catenin signaling that promoted CL6 cardiomyogenesis. CONCLUSIONS/SIGNIFICANCE: Grem1 enhances the determined path to cardiomyogenesis in a stage-specific manner, and inhibition of the BMP signaling pathway is involved in initial determination of Grem1-promoted cardiomyogenesis. Our results shed new light on renewal of the cardiovascular system using Grem1 in human

    Non-traumatic myositis ossificans mimicking a malignant neoplasm in an 83-year-old woman: a case report

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    <p>Abstract</p> <p>Introduction</p> <p>Myositis ossificans is a benign, self-limiting condition that usually affects young, athletically active men. To the best of our knowledge, this case report describes the oldest recorded patient with myositis ossificans.</p> <p>Case presentation</p> <p>Our patient was an 83-year-old Japanese woman who presented with a one week history of a palpable mass in the left thigh. She had a history of surgery for transverse colon cancer and lung cancer at the ages of 73 and 80, respectively. Clinical and radiological examinations suggested a malignant neoplasm such as metastatic carcinoma or extraskeletal osteosarcoma. A diagnosis of myositis ossificans was made by core needle biopsy. Our patient was asymptomatic and had no recurrence at one year follow-up.</p> <p>Conclusion</p> <p>Clinicians should consider myositis ossificans as a possible diagnosis for a soft tissue mass in the limb of an older patient, thereby avoiding unnecessarily aggressive therapy.</p

    Rice Annotation Database (RAD): a contig-oriented database for map-based rice genomics

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    A contig-oriented database for annotation of the rice genome has been constructed to facilitate map-based rice genomics. The Rice Annotation Database has the following functional features: (i) extensive effort of manual annotations of P1-derived artificial chromosome/bacterial artificial chromosome clones can be merged at chromosome and contig-level; (ii) concise visualization of the annotation information such as the predicted genes, results of various prediction programs (RiceHMM, Genscan, Genscan+, Fgenesh, GeneMark, etc.), homology to expressed sequence tag, full-length cDNA and protein; (iii) user-friendly clone / gene query system; (iv) download functions for nucleotide, amino acid and coding sequences; (v) analysis of various features of the genome (GC-content, average value, etc.); and (vi) genome-wide homology search (BLAST) of contig- and chromosome-level genome sequence to allow comparative analysis with the genome sequence of other organisms. As of October 2004, the database contains a total of 215 Mb sequence with relevant annotation results including 30 000 manually curated genes. The database can provide the latest information on manual annotation as well as a comprehensive structural analysis of various features of the rice genome. The database can be accessed at http://rad.dna.affrc.go.jp/

    Intracapsular pressure and interleukin-1β cytokine in hips with acetabular dysplasia

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    Background and purpose Several studies have demonstrated an increased intracapsular pressure in several hip disorders such as septic arthritis, synovitis, and trauma. We therefore measured the intracapsular pressure in different positions in early dysplasic hips and its relation to the concentration of interleukin-1β (IL-1β), the volume of joint fluid, and the clinical and radiographic findings before a periacetabular osteotomy

    Effect of combined treatment with alendronate and calcitriol on femoral neck strength in osteopenic rats

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    <p>Abstract</p> <p>Background</p> <p>Hip fracture is associated with pronounced morbidity and excess mortality in elderly women with postmenopausal osteoporosis. Many drugs have been developed to treat osteoporosis and to reduce the risk of osteoporotic fractures. We investigated the effects of combined alendronate and vitamin D<sub>3 </sub>treatment on bone mass and fracture load at the femoral neck in ovariectomized (OVX) rats, and evaluated the relationship between bone mass parameters and femoral neck strength.</p> <p>Methods</p> <p>Thirty 12-week-old female rats underwent either a sham-operation (n = 6) or OVX (n = 24). Twenty weeks later, OVX rats were further divided into four groups and received daily doses of either saline alone, 0.1 mg/kg alendronate, 0.1 μg/kg calcitriol, or a combination of both two drugs by continuous infusion via Alzet mini-osmotic pumps. The sham-control group received saline alone. After 12 weeks of treatment, femoral necks were examined using peripheral quantitative computed tomography (pQCT) densitometry and mechanical testing.</p> <p>Results</p> <p>Saline-treated OVX rats showed significant decreases in total bone mineral content (BMC) (by 28.1%), total bone mineral density (BMD) (by 9.5%), cortical BMC (by 26.3%), cancellous BMC (by 66.3%), cancellous BMD (by 29.0%) and total cross-sectional bone area (by 30.4%) compared with the sham-control group. The combined alendronate and calcitriol treatments improved bone loss owing to estrogen deficiency. On mechanical testing, although OVX significantly reduced bone strength of the femoral neck (by 29.3%) compared with the sham-control group, only the combined treatment significantly improved the fracture load at the femoral neck in OVX rats to the level of the sham-controls. The correlation of total BMC to fracture load was significant, but that of total BMD was not.</p> <p>Conclusion</p> <p>Our results showed that the combined treatment with alendronate and calcitriol significantly improved bone fragility of the femoral neck in OVX osteopenic rats.</p
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