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Search Results: 1 - 10 of 2368 matches for " Yuta Ito "
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Dermatomyositis Associated with Docetaxel Use in the Treatment for Ovarian Cancer  [PDF]
Yuta Ito, Yuko Hamada, Keiko Katayama, Hirokazu Uno, Tokio Nakada
Case Reports in Clinical Medicine (CRCM) , 2017, DOI: 10.4236/crcm.2017.610031
Abstract: A 50-year-old woman presented with a 1-week history of rash on the face and hands and difficulty when rising from a sitting position. She underwent an exploratory laparotomy for ovarian cancer 8 months ago. Three months ago, she underwent total hysterectomy, adnexectomy, and retroperitoneal lymph node dissection. Docetaxel and carboplatin were started and administered twice. Physical examination revealed periorbital edema with a purplish appearance; Erythematous lesions on radiodorsal aspects of the proximal interphalangeal and metacarpophalangeal joints were seen. We diagnosed as dermatomyositis on the basis of clinical findings. Interview demonstrated that such rashes were enhanced 1 week after chemotherapy, and got better through following one week. Cutaneous and muscular symptoms got worse two months after her initial visit. Myotonia was found in electromyography, and high density areas on both femoral regions and lower thighs were observed by MRI of skeletal muscle. Scleroderma-like lesions are known as an adverse effect to taxane. In addition, three cases of dermatomyositis due to taxane were reported in Japan. Since dermatomyositis was regarded as one of paraneoplastic syndrome generally, it was not considered as drug-induced. However, clinical course of our case suggests that docetaxel may play more important role in activity of dermatomyositis than ovarian cancer. Seeing patients treated with taxane, therefore, we have to be careful for symptoms suggestive of autoimmune diseases: not only scleroderma but dermatomyositis.
Power-law expansion of the Universe from the bosonic Lorentzian type IIB matrix model
Yuta Ito,Jun Nishimura,Asato Tsuchiya
Physics , 2015,
Abstract: Recent studies on the Lorentzian version of the type IIB matrix model show that (3+1)D expanding universe emerges dynamically from (9+1)D space-time predicted by superstring theory. Here we study a bosonic matrix model obtained by omitting the fermionic matrices. With the adopted simplification and the usage of a large-scale parallel computer, we are able to perform Monte Carlo calculations with matrix size up to $N=512$, which is twenty times larger than that used previously for the studies of the original model. When the matrix size is larger than some critical value $N_{\rm c}\simeq 110$, we find that (3+1)D expanding universe emerges dynamically with a clear large-$N$ scaling property. Furthermore, at sufficiently late times, we observe a power-law behavior $t^{1/2}$ of the spatial extent with respect to time $t$, which is reminiscent of the expanding behavior of the Friedmann-Robertson-Walker universe in the radiation dominated era. We discuss possible implications of this result on the original model including fermionic matrices.
Large-scale computation of the exponentially expanding universe in a simplified Lorentzian type IIB matrix model
Yuta Ito,Jun Nishimura,Asato Tsuchiya
Physics , 2015,
Abstract: The type IIB matrix model is a conjectured nonperturbative formulation of superstring theory. Recent studies on the Lorentzian version of the model have shown that only three out of nine spatial directions start to expand after some critical time. On the other hand, due to the unbounded action of the Lorentzian model, one has to introduce infrared (IR) cutoffs in order to make the partition function finite. In this work we investigate whether the effects of the IR cutoffs disappear in the infinite volume limit. For that purpose, we study a simplified model with large matrix size up to $N=256$ by Monte Carlo simulation. First we confirm the exponentially expanding behavior of the "universe". Then we generalize the form of the IR cutoffs by one parameter, and find that the results become universal in some region of the parameter. It is suggested that the effects of IR cutoffs disappear in this region, which is confirmed also from the studies of Schwinger-Dyson equations.
Segmental arterial mediolysis accompanied by renal infarction and pancreatic enlargement: a case report
Ito Nobuhisa,Kuwahara Go,Sukehiro Yuta,Teratani Hiromitsu
Journal of Medical Case Reports , 2012, DOI: 10.1186/1752-1947-6-307
Abstract: Introduction Due to recent advances in imaging diagnostic techniques, there are an increasing number of case reports of segmental arterial mediolysis. However, there are only a limited number of reports on segmental arterial mediolysis-related abnormalities of abdominal organs other than the intestine. This report describes a case of segmental arterial mediolysis accompanied by abnormalities of abdominal organs without clinical symptoms. Case presentation A 52-year-old Japanese man with hematuria and no prior medical history was referred to a urologist and was diagnosed as having urinary bladder cancer. He underwent trans-urethral resection of the bladder tumor and intra-vesical instillation therapy, which was followed by observation. During follow-up, although no abdominal symptoms were observed, an abdominal computed tomography scan revealed a dissection of the superior mesenteric artery. A false lumen partially occluded by a thrombus was located distal to this occlusion. The lumen was irregularly shaped with narrow and wide sections. Similar irregularities were also observed in the wall of the inferior mesenteric artery. Arterial dissection with thromboembolism in the left renal artery and renal infarction was also observed. Follow-up computed tomography after two months revealed an enlargement of the pancreatic tail adjacent to the splenic artery. Follow-up three-dimensional computed tomography showed gradual re-expansion of the true lumen of the superior mesenteric artery, improvement in arterial wall irregularities, and a reduction in the pancreas enlargement and renal infarction. Over the following 15 months, these changes gradually normalized. On the basis of the vascular changes in multiple arterial systems that resolved spontaneously, we considered that the lesions were associated with segmental arterial mediolysis. Conclusions We present a rare case of segmental arterial mediolysis accompanied by abnormalities of abdominal organs without clinical symptoms. Three-dimensional computed tomography was useful for follow-up evaluation in our patient.
Monte Carlo studies on the expanding behavior of the early universe in the Lorentzian type IIB matrix model
Yuta Ito,Sang-Woo Kim,Jun Nishimura,Asato Tsuchiya
Physics , 2013,
Abstract: The type IIB matrix model is a conjectured nonperturbative formulation of superstring theory. Recently the Lorentzian version of the model has been studied by Monte Carlo simulation, and it has been shown that only three out of nine spatial directions start to expand after a critical time. We extend this work by investigating the expanding behavior for much longer time. We find that the 3d space expands exponentially for some period of time, which may be interpreted as inflation. We also simulate a simplified model, which is expected to capture some qualitative features of the original model at much later times. We observe that the exponential expansion eventually changes into a power-law t^(1/2) behavior, which agrees with the expanding behavior of the Friedmann-Robertson-Walker (FRW) universe in the radiation dominated era.
A renormalization group method for studying the early universe in the Lorentzian IIB matrix model
Yuta Ito,Sang-Woo Kim,Yuki Koizuka,Jun Nishimura,Asato Tsuchiya
Physics , 2013,
Abstract: We propose a new method for studying the early universe in the Lorentzian version of the IIB matrix model, which is considered to be a nonperturbative formulation of superstring theory. This method is based on the idea of renormalization group, and it enables us to study the time-evolution of the universe for much longer time than in the previous work, which showed that the SO(9) rotational symmetry is spontaneously broken down to SO(3) after a "critical time". We demonstrate how this method works in a simplified model, which is expected to capture the behaviors of the original model when the space is not so large. In particular, we present clear evidence that the three-dimensional space expands exponentially after the critical time in this simplified model.
Robust Optimum Design of Thrust Hydrodynamic Bearings for Hard Disk Drives  [PDF]
Hiromu Hashimoto, Yuta Sunami
Applied Mathematics (AM) , 2012, DOI: 10.4236/am.2012.330193
Abstract: This paper describes the robust optimum design which combines the geometrical optimization method proposed by Hashimoto and statistical method. Recently, 2.5″ hard disk drives (HDDs) are widely used for mobile devices such as laptops, video cameras and car navigation systems. In mobile applications, high durability towards external vibrations and shocks are essentials to the bearings of HDD spindle motor. In addition, the bearing characteristics are influenced by manufacturing error because of small size of the bearings of HDD. In this paper, the geometrical optimization is carried out to maximize the bearing stiffness using sequential quadratic programming to improve vibration characteristics. Additionally, the bearing stiffness is analyzed considering dimensional tolerance of the bearing using statistical method. The dimensional tolerance is assumed to distribute according to the Gaussian distribution, and then the bearing stiffness is estimated by combining the expectation and standard deviation. As a result, in the robust optimum design, new groove geometry of bearing can be obtained in which the bearing stiffness is four times higher than the stiffness of conventional spiral groove bearing. Moreover, the bearing has lower variability compared with the result of optimum design neglecting dimensional tolerance.
Electricity Generation System with Piezoelectric Element Using Acoustic Radiation Energy  [PDF]
Hiroyuki Moriyama, Yuta Yamamura
Journal of Power and Energy Engineering (JPEE) , 2018, DOI: 10.4236/jpee.2018.610001
Abstract: In this study, a circular plate that is installing a piezoelectric element at its center is adopted as energy-harvesting system and is subjected to a harmonic point force. Because this system cannot avoid the influence of its acoustic radiation, the influence is considered theoretically using the equation of plate motion taking into account its radiation impedance and is estimated by the electricity generation efficiency, which is derived from the ratio of the electric power in the electricity generation and the mechanical power supplied to the plate. As a result, the efficiency is suppressed by the acoustic radiation from the plate, so that the efficiencies are so different in whether to take into consideration the radiation impedance or not. Because those results are verified by the electricity generation experiment and radiation acoustic energy has a hopeful prospect for improving the performance of this system, mechanical-acoustic coupling is used to make the most of the acoustic energy. Therefore, a cylinder that has the above plates at both ends is also adopted as the electricity generation system and mechanical-acoustic coupling is caused between the plate vibrations and an internal sound field into the cylindrical enclosure by subjecting one side of each plate to a harmonic point force. Then, the effect of coupling is evaluated by comparing with the efficiencies in the electricity generation system of only plate. Specifically, because the radiation impedance increases with the plate thickness, i.e., with the natural frequency of the plate, it is demonstrated that the effect of coupling becomes remarkable with increasing the thickness on the electricity generation efficiency.
Is Gastrectomy-Induced High Turnover of Bone with Hyperosteoidosis and Increase of Mineralization a Typical Osteomalacia?
Takashi Ueyama, Yuta Yamamoto, Kazuki Ueda, Aiji Yajima, Yoshimasa Maeda, Yasunobu Yamashita, Takao Ito, Yoshihiro Tsuruo, Masao Ichinose
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0065685
Abstract: Gastrectomy (GX) is thought to result in osteomalacia due to deficiencies in Vitamin D and Ca. Using a GX rat model, we showed that GX induced high turnover of bone with hyperosteoidosis, prominent increase of mineralization and increased mRNA expression of both osteoclast-derived tartrate-resistant acid phosphatase 5b and osteocalcin. The increased 1, 25(OH)2D3 level and unchanged PTH and calcitonin levels suggested that conventional bone and Ca metabolic pathways were not involved or changed in compensation. Thus, GX-induced bone pathology was different from a typical osteomalacia. Gene expression profiles through microarray analysis and data mining using Ingenuity Pathway Analysis indicated that 612 genes were up-regulated and 1,097 genes were down-regulated in the GX bone. These genes were related functionally to connective tissue development, skeletal and muscular system development and function, Ca signaling and the role of osteoblasts, osteoclasts and chondrocytes. Network analysis indicated 9 genes (Aldehyde dehydrogenase 1 family, member A1; Aquaporin 9; Interleukin 1 receptor accessory protein; Very low density lipoprotein receptor; Periostin, osteoblast specific factor; Aggrecan; Gremlin 1; Angiopoietin-like 4; Wingless-type MMTV integration site family, member 10B) were hubs connected with tissue development and immunological diseases. These results suggest that chronic systemic inflammation might underlie the GX-induced pathological changes in bone.
Classically conformal B-L extended Standard Model and phenomenology
Orikasa, Yuta
High Energy Physics - Phenomenology , 2013,
Abstract: Bardeen has argued that once the classically conformal invariance and its minimal violation by quantum anomalies are imposed on the SM, it can be free from the quadratic divergences and hence the gauge hierarchy problem. Under the hypothesis, We investigated the minimal B-L extended SM with a flat Higgs potential at the Planck scale. In this model, the B-L symmetry is radiatively broken at TeV scale. We studied phenomenology and detectability of the model at LHC and the ILC.
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