169 research outputs found

    Fully coupled-channel study of KppK^-pp resonance in a chiral SU(3)-based KˉN\bar{K}N potential

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    We have investigated the most essential kaonic nucleus "KppK^-pp" as a resonant state of the KˉNN\bar{K}NN-πΣN\pi\Sigma N-πΛN\pi\Lambda N coupled channel system using a chiral SU(3)-based KˉN\bar{K}N potential. We treat the "KppK^-pp" resonance adequately with a fully coupled-channel complex scaling method (full ccCSM). Self-consistency needs to be considered for the energy dependence of the chiral SU(3)-based potential. In the present study, we propose a simple prescription for the treatment of self-consistency, considering the {\it averaged threshold} and {\it averaged binding energy of mesons}. With this prescription, we have successfully found the self-consistent solutions of the "KppK^-pp" three-body resonance. The results indicate that the "KppK^-pp" system is bound rather shallowly. In particular, when the potential parameters are constrained with the latest KˉN\bar{K}N scattering length, the binding energy and half of the mesonic decay width are obtained as 145014-50 MeV and 8198-19 MeV, respectively.Comment: 7 pages, 2 figures, accepted by Phys. Lett.

    Investigation of KbarNNK^{bar}NN resonances with a coupled-channel Complex Scaling Method + Feshbach projection

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    We have investigated a prototype of kaonic nuclei, "KppK^-pp", with a coupled-channel Complex Scaling Method (ccCSM). Combining the ccCSM with Feshbach projection method, we can handle a coupled-channel problem effectively as a single-channel problem. By using an energy-dependent chiral SU(3)-based KˉN\bar{K}N potential, the KppK^-pp (Jπ=0J^\pi=0^- and T=1/2T=1/2) is obtained to be shallowly bound with the binding energy of 20-30 MeV. The mesonic decay width depends on the interaction parameters and ansatz; the decay width is ranging from 20 to 65 MeV. In case of Jπ=1J^\pi=1^- state, no three-body KˉNN\bar{K}NN resonant states are found.Comment: 6 pages, 3 figures, Proceedings of "International Conference on Exotic Atoms and Related Topics (EXA2014)", Vienna, Austria, Sept. 15-19, 2014, to be published in Hyperfine Interaction

    Dynamics of rheumatoid joint

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    In the present communication the recent works done by the Rheumatism Research Group of Department of Orthopedic Surgery, Okayama University, are described. The principal findings may briefly be summarized as follows. 1. Pathohistological pictures of the synovial membrane are classified into six types. Among them, Fibrinoid type and Follicular-Fibrosis type are the representative ones of chronic rheumatoid arthritis. 2. For the evaluation of the systemic as well as the local activities in rheumatoid arthritis and for judging the therapeutic effect, some indices have been established. 3. Injection of steroid hormones into the local joints fails to give satisfactory results in advanced, chronic rheumatoid arthritis. In such instances the flushing of the joint with physiological saline solution is effective. 4. In the case of chronic rheumatoid arthritis where the inflammation of hand and phalangeal joints is marked, RA-test gives rapid and more intense reaction, and most of such cases are of Follicular-Fibrosis type. 5. When lymph follicles appearing in the synovial membrane are stained when methyl green pyronine, the arrangement of lymphoid cells and plasma cells becomes distinctly clear. By micro-autoradiographic observations it can be seen that ³H-thymindine injected into the joint cavity is mostly ingested by the lymphoid cells in lymph follicles. 6. In the observation by the fluorescent antibody method multinuclear leucocytes found in the joint fluid and in the peripheral blood react with 19S and 7S-gamma-globulins. 7. When the serum and the joint fluid of the patient with rheumatoid arthritis are fractionated, they separate into three peaks at 19S, 7S, and 4S. Both S. S. C. A.-test and L. F. T. tests reveal the peak at 19S. The serum of chronic hepatitis positive to RA-test and the serum of rheumatoid arthritis are found to react immunologically the same to anti-&#946;2 M globulin sheep serum. 8. When the reticulo-endothelial system of rat is blocked by 900,000 molecules of poly-vinyl-pyrroridon, the ability of antibody production is diminished. 9. Chemical synovectomy of injecting osmic acid is effective to FibrinoidCoating type. Its action mechanism lies in the complete cleaning of the surface of synovial membrane. 10. By radiating synovectomy with 193Au a fairly good result can be expected. 198Au is ingested by those cells in the surface layer of the synovial membrane and also by histiocytes in the synovial membrane. When 5 mc of 198Au are injected into the knee joint, a marked necrosis of the synovial membrane occurs. When 198Au is added to the ascites cells of rabbit during the tissue culture, in the concentration of over 14 &#956;C degeneration of these cells can be recognized. 11. From the examination results of prognosis on those 25 cases with 41 rheumatoid knee joints after surgical synovectomy, it is considered that this method is indicated for Follicular-Fibrosis type. Ones with rheumatoid knee joint of Fibrinoid-Coating type gold sol treatment should be resorted to. In the cases of hand joints, surgical synovectemy is to be recommended at a relatively early stage.</p

    Surface Modification with Metal Hexacyanoferrates for Expanding the Choice of H₂-Evolving Photocatalysts for Both Fe³⁺/Fe²⁺ Redox-Mediated and Interparticle Z-Scheme Water-Splitting Systems

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    The construction of Z-scheme water splitting systems is an effective approach toward harvesting a wide portion of the solar light spectrum; however, the success has often depended on the property of photocatalyst surfaces. This drawback is typified by the limited choice of efficient H₂ evolution photocatalysts (HEPs) (e.g., Rh-doped SrTiO₃) for Z-scheme water splitting using Fe³⁺/Fe²⁺ redox couple. The majority of visible light-responsive materials shows low activity for H2 production with Fe²⁺ electron donors despite having suitable band levels, probably due to the absence of an effective surface site for oxidizing Fe²⁺. The choice of HEPs for interparticle Z-scheme systems has also been limited. Herein, an effective strategy for overcoming these limitations is reported: activation of originally inactive materials via surface modification with metal hexacyanoferrate nanoparticles. Photocatalytic H2 evolution over TaON in aqueous Fe²⁺ solution is drastically enhanced by comodification with indium hexacyanoferrate (InHCF) and Rh–Cr mixed oxide. InHCF promotes Fe²⁺ oxidation to Fe³⁺ utilizing the holes photogenerated in TaON via FeIII/FeII redox cycles, enabling Z-scheme water splitting with the Fe³⁺/Fe²⁺ redox mediator coupled with an O2 evolution photocatalyst under visible light. It is also disclosed that InHCF nanoparticles function as effective solid electron mediators for achieving interparticle Z-scheme water splitting

    Risk factors for lumbar intervertebral disc height narrowing: a population-based longitudinal study in the elderly

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    BACKGROUND: The progression of disc degeneration is generally believed to be associated with low back pain and/or degenerative lumbar diseases, especially in the elderly. The purpose of this study was to quantitatively evaluate changes in lumbar disc height using radiographic measurements and to investigate risk factors for development of disc height narrowing of the elderly. METHODS: From 1997 to 2007, 197 village inhabitants at least 65 years-old who participated in baseline examinations and more than four follow-up examinations conducted every second year were chosen as subjects for this study. Using lateral lumbar spine radiographs of each subject, L1-L2 to L5-S1 disc heights were measured. The subjects were divided into two groups according to the rate of change in disc height: mildly decreased (≤20 % decrease) and severely decreased (>20 % decrease). A stepwise multiple logistic regression analysis was used to select those factors significantly associated with disc height narrowing. RESULTS: Disc height at each intervertebral disc (IVD) level decreased gradually over ten years (p < 0.01, an average 5.8 % decrease of all disc levels). There was no significant difference in the rate of change in disc height among the IVD levels. Female gender, radiographic knee osteoarthritis and low back pain at baseline were associated with increased risk for disc height narrowing. CONCLUSIONS: We conducted the first population-based cohort study of the elderly that quantitatively evaluated lumbar disc height using radiographic measurements. The risk factors identified in this study would contribute to a further understanding the pathology of disc degeneration

    Complications Associated With Spine Surgery in Patients Aged 80 Years or Older: Japan Association of Spine Surgeons with Ambition (JASA) Multicenter Study

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    Study Design:Retrospective study of registry data.Objectives:Aging of society and recent advances in surgical techniques and general anesthesia have increased the demand for spinal surgery in elderly patients. Many complications have been described in elderly patients, but a multicenter study of perioperative complications in spinal surgery in patients aged 80 years or older has not been reported. Therefore, the goal of the study was to analyze complications associated with spine surgery in patients aged 80 years or older with cervical, thoracic, or lumbar lesions.Methods:A multicenter study was performed in patients aged 80 years or older who underwent 262 spinal surgeries at 35 facilities. The frequency and severity of complications were examined for perioperative complications, including intraoperative and postoperative complications, and for major postoperative complications that were potentially life threatening, required reoperation in the perioperative period, or left a permanent injury.Results:Perioperative complications occurred in 75 of the 262 surgeries (29%) and 33 were major complications (13%). In multivariate logistic regression, age over 85 years (hazard ratio [HR] = 1.007, P = 0.025) and estimated blood loss ≥500 g (HR = 3.076, P = .004) were significantly associated with perioperative complications, and an operative time ≥180 min (HR = 2.78, P = .007) was significantly associated with major complications.Conclusions:Elderly patients aged 80 years or older with comorbidities are at higher risk for complications. Increased surgical invasion, and particularly a long operative time, can cause serious complications that may be life threatening. Therefore, careful decisions are required with regard to the surgical indication and procedure in elderly patients

    Risk Factors for Delirium After Spine Surgery in Extremely Elderly Patients Aged 80 Years or Older and Review of the Literature: Japan Association of Spine Surgeons with Ambition Multicenter Study

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    Study Design:Retrospective database analysis.Objective:Spine surgeries in elderly patients have increased in recent years due to aging of society and recent advances in surgical techniques, and postoperative complications have become more of a concern. Postoperative delirium is a common complication in elderly patients that impairs recovery and increases morbidity and mortality. The objective of the study was to analyze postoperative delirium associated with spine surgery in patients aged 80 years or older with cervical, thoracic, and lumbar lesions.Methods:A retrospective multicenter study was performed in 262 patients 80 years of age or older who underwent spine surgeries at 35 facilities. Postoperative complications, incidence of postoperative delirium, and hazard ratios of patient-specific and surgical risk factors were examined.Results:Postoperative complications occurred in 59 of the 262 spine surgeries (23%). Postoperative delirium was the most frequent complication, occurring in 15 of 262 patients (5.7%), and was significantly associated with hypertension, cerebrovascular disease, cervical lesion surgery, and greater estimated blood loss (P < .05). In multivariate logistic regression using perioperative factors, cervical lesion surgery (odds ratio = 4.27, P < .05) and estimated blood loss ≥300 mL (odds ratio = 4.52, P < .05) were significantly associated with postoperative delirium.Conclusions:Cervical lesion surgery and greater blood loss were perioperative risk factors for delirium in extremely elderly patients after spine surgery. Hypertension and cerebrovascular disease were significant risk factors for postoperative delirium, and careful management is required for patients with such risk factors

    XPS Study of H-Terminated Silicon Surface under Inert Gas and UHV Annealing

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    We have investigated the changes of chemical bonding states of an H-terminated silicon surface under inert gas (Ar,N 2 ) and ultrahigh vacuum ͑UHV͒ annealing using X-ray photoelectron spectroscopy ͑XPS͒ and thermal desorption spectroscopy ͑TDS͒. SiC is formed ͑corresponding to ϳ0.1 monolayer͒ under inert gas and UHV annealing at around 500°C, which is coincident with the temperature of the dangling bonds formation at the silicon surface by hydrogen desorption, whereas SiC is not formed under O 2 annealing. From the precise analysis using a combination of XPS and TDS, the SiC formation is related to the reaction between the silicon surface and the organic contamination that is unavoidably adsorbed during air exposure. We also studied the electrical properties of metal oxide semiconductor capacitors with a chemical vapor deposited silicon oxide gate insulator formed on It is of great importance to obtain high reliability in less than 1.5 nm thick silicon oxide gate dielectrics for 65 nm metal oxide semiconductor ͑MOS͒ devices. Pyrogenic oxides have been frequently applied for the gate dielectrics up to the present. In a conventional furnace, an uncontrollable oxide layer is grown at low temperatures in the preannealing process because O 2 gas in the air unavoidably enters the furnace chamber simultaneously at the wafer loading step. 1 The growth of the uncontrollable oxide layer deteriorates the reliability of the gate dielectrics because the time-dependent dielectric breakdown ͑TDDB͒ characteristic of a MOS capacitor with silicon oxide film grown by dry O 2 at low temperature is inferior to that with a pyrogenic oxide film grown at high temperature. 1 A furnace equipped with a load lock chamber that can control residual O 2 is necessary to prevent the uncontrollable oxide layer formation. H-termination with HF treatment is also necessary to remove the chemical oxide layer formed by the RCA cleaning process and to deactivate the silicon surface. 2-7 Although the uncontrollable oxide or the chemical oxide layer is only about 1 nm thick, it is necessary to prevent the formation of these oxide layers to realize 1.5 nm thick, highly reliable gate dielectrics. Previously, it was reported that the TDDB characteristic for MOS capacitors degrades when using a load lock chamber after HF treatment. 8 It would be caused by remaining organic contamination or etching on the silicon surface by residual O 2 and H 2 O. 9,10 However, a microscopic mechanism for the TDDB degradation still remains unclear. In this paper, we investigate the influence of inert gas (Ar,N 2 ) and ultrahigh vacuum ͑UHV͒ annealing with a load lock chamber on the chemical bonding state and roughness of H-terminated silicon surfaces by X-ray photoelectron spectroscopy ͑XPS͒ and thermal desorption spectroscopy ͑TDS͒ analysis and atomic force microscopic ͑AFM͒ observation. The insulation characteristics of gate dielectrics fabricated on these silicon surfaces are also studied. The microscopic mechanism of reliability deterioration of the gate dielectrics fabricated with inert gas and UHV preannealing after HF treatment is discussed. Experimental 2-5 Some of them were annealed in O 2 , Ar, N 2 , or UHV at 800°C, as shown in Moreover, some of the samples were annealed in UHV at various temperatures ranging from room temperature to 800°C as shown in The TDS equipment was ESCO EMD-WA1000S. During the TDS measurement, the base pressure was below 4 ϫ 10 Ϫ7 Pa and the annealing rate was 60°C/min. The temperature of the sample surface was calibrated with the temperature of the CO (m/e ϭ 28) desorption peak ͑520°C͒ generated by thermal decomposition of calcium oxalate spread on a silicon wafer surface. The XPS spectra were obtained using a PHI ESCA 5400 photoelectron spectrometer with Mg K␣ excitation, and the takeoff angle was 45°. AFM images are observed in tapping mode using a Digital Instruments Nanoscope II. The MOS capacitors were fabricated on n-type silicon ͑100͒ substrate with an n ϩ polycrystalline-silicon gate electrode. Prior to the 6.5 nm thick gate oxide growth at 800°C, the silicon surface was etched with HF solution followed by annealing in Ar or O 2 atmosphere. To investigate the influence of inert gas annealing on the silicon surface, the chemical vapor deposition ͑CVD͒ technique was used to form silicon oxide gate dielectrics, and current-voltage characteristics were measured in positive gate bias
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