61 research outputs found

    Systematic characterization of upper critical fields for MgB2_2 thin films using the two-band superconducting theory

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    We present experimental results of the upper critical fields Hc2H_{\rm c2} of various MgB2_2 thin films prepared by the molecular beam epitaxy, multiple-targets sputtering, and co-evaporation deposition apparatus. Experimental data of the Hc2(T)H_{\rm c2}(T) are successfully analyzed by applying the Gurevich theory of dirty two-band superconductivity in the case of Dπ/Dσ>1D_{\pi}/D_{\sigma}>1, where DπD_{\pi} and DσD_{\sigma} are the intraband electron diffusivities for π\pi and σ\sigma bands, respectively. We find that the parameters obtained from the analysis are strongly correlated to the superconducting transition temperature TcT_{\rm c} of the films. We also discuss the anormalous narrowing of the transition width at intermediate temperatures confirmed by the magnetoresistance measurements.Comment: 7 pages, 7 figures, submitted to Phys. Rev.

    Efficacy of SGLT2 inhibitors in IgA nephropathy associated with alcoholic liver cirrhosis accompanied by nephrotic syndrome: a case report

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    We present a 51-year-old male patient with a history of Child-Pugh Grade B alcoholic liver cirrhosis (ALC) who developed renal impairment (serum creatinine of 2.00 mg/dL) and nephrotic syndrome (a urinary protein level of 4.35 g/gCr). The patient was diagnosed with immunoglobulin A nephropathy (IgAN) associated with ALC based on findings from comprehensive evaluations, including markedly elevated serum IgA levels (883.7 mg/dL), a kidney biopsy revealing significant IgA deposition in the para-mesangial area, and a liver diagnosis showing long-standing advanced ALC. Our treatment approach involved initiating dapagliflozin therapy, a sodium-glucose cotransporter-2 (SGLT2) inhibitor, alongside strict alcohol abstinence. Remarkably, the patient demonstrated a dramatic reduction in proteinuria within one week of dapagliflozin administration. No hypoglycemic events were observed. This case adds valuable clinical insights into the potential therapeutic role of SGLT2 inhibitors in IgAN associated with ALC. Specifically, in cases where conventional steroid therapies may be contraindicated due to coexisting comorbidities such as diabetes or obesity, dapagliflozin emerges as a potentially efficacious alternative. Further investigations are warranted to validate these preliminary observations

    Reexamination of Refrigeration Power of the LHD Cryogenic System After Fire and Restart of Operation

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    The Large Helical Device (LHD), built in the 1990s, is a heliotron-type fusion plasma experimental device with the world\u27s first fully superconducting magnetic confinement system. The LHD cryogenic system operated stably for 18 years from 1998 to 2015 with high availability exceeding 99%. Unfortunately, in August 2015, a fire occurred in the cold box of the He refrigerator during maintenance, and nonmetallic components such as multilayer insulation films, temperature sensors, and measuring instruments were burnt down. Repair work started in November 2015 and completed at the end of July 2016. In August 2016, a test operation of the He refrigerator was conducted, and the refrigeration power was compared with that measured in the initial performance test conducted in 1995. The measured equivalent refrigeration power at 4.4 K was 9.19 kW, representing a decrease ~2% from the value of 9.38 kW measured in 1995. We attributed this slight decrease in refrigeration power to performance deterioration owing to aging over 18 years and not to the fire. The LHD restarted operation in January 2017, and its 19th operational cycle for a deuterium plasma experiment was conducted successfully up to August 2017. This paper reports the operational history and restart of the LHD superconducting magnet and cryogenic system

    Bilateral dual iliac screws in spinal deformity correction surgery

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    Abstract Background Surgery for adult spinal deformity requires optimal patient-specific spino-pelvic-lower extremity alignment. Distal fixation in thoracolumbar spinal deformity surgery is crucial when arthrodesis to the sacrum is indicated. Although we had performed sacro-pelvic fixation with bilateral S1 and bilateral single iliac screws previously, iliac screw loosening and/or S1 screw loosening occurred frequently. So, the authors attempted to fuse spino-pelvic lesions with the dual iliac screws and S1 pedicle screws. Methods Twenty-seven consecutive adult spinal deformity patients underwent thoracolumbar-pelvic correction surgery with bilateral double iliac screws between May 2014 and September 2015. Sagittal vertical axis, lumbar lordosis, pelvic tilt, sacral slope, T1 pelvic angle, and global tilt were assessed radiographically and by computed tomography both preoperatively and 24 months postoperatively. Iliac screw loosening, S1 pedicle screw loosening, and screw penetration of the ilium were evaluated 2 years postoperatively. Results Only two patients (7.4%) at 1 year and three patients (11.1%) at 2 years presented with iliac screw loosening postoperatively. Loosening of the S1 screw occurred in three cases (11.1%) 2 years postoperatively. Displacement of the iliac screw occurred in eight cases (25%). Internal and external perforation of the ilium by the iliac screw occurred in six (22.2%) and three (11.1%) cases respectively. One reoperation was performed due to back-out of the iliac screw and rod breakage. Conclusion Bilateral dual iliac screws and an S1 pedicle screw system achieve longer stability for spinal and pelvic fusion in adult spinal deformity patients, with few severe complications

    Risk Factors for Clinically Relevant Loosening of Percutaneous Pedicle Screws

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    Introduction: (1) To evaluate the influence of pedicle screw loosening on clinical outcomes; (2) to clarify the association between the pull-out length and screw loosening 1 year after surgery; and (3) to determine radiographically which screw parameters predominantly influence the pull-out resistance of screws. Methods: We analyzed 32 consecutive patients who underwent minimally invasive lumbar or thoracic spinal stabilization by intraoperative three-dimensional computed tomography (CT)-guided navigation without anterior reconstruction and were followed up for 1 year. The screw pull-out length was measured on axial CT images obtained both immediately after screw insertion and postoperatively. Loosening of screws and clinical outcomes were evaluated radiographically, clinically, and by CT 1 year after surgery. Results: There were no significant differences in the mean age, sex, bone mineral density, mean stabilized length, and smoking habits of patients with (+) or without (−) loosening. The Oswestry Disability Index and the lumbar visual analog scale 1 year after surgery were significantly higher in patients with loosening (+) than in those without (−). The overall pedicle screw pull-out rate was 16.2% (47/290) of screws and the overall screw loosening rate was 15.2% (44/290) of screws. Screws with loosening (+) had significantly lower (axial) trajectory angles and higher screw pull-out lengths than those without (−). Approximately 82% of loosened screws had been pulled out during rod connection. Conclusions: A lower axial trajectory and an increased screw pull-out length after rod reduction are crucial risk factors for screw loosening

    Clinical significance of para‐carinal air cysts in patients with pleuroparenchymal fibroelastosis: The relationship with pneumomediastinum and pneumothorax

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    Abstract Background Para‐tracheal or para‐carinal air cysts (PACs) are often asymptomatic and usually detected incidentally by methods such as computed tomography. Their clinical significance is unclear in patients with pleuroparenchymal fibroelastosis (PPFE). Methods We evaluated the clinical significance of PACs in PPFE and their relationship with pneumomediastinum or pneumothorax. Results In total, 50 patients had PPFE and 34 (68%) had PACs. Most PACs were para‐carinal (n = 30). A para‐tracheal air cyst was detected in only nine patients, which included five patients having both para‐carinal and para‐tracheal air cysts. Overall median survival was 24.7 months. Survival was not significantly different between the patients with [PACs(+)] and without PACs (P = 0.268). A high frequency (64%) of the complication of pneumomediastinum or pneumothorax occurred in the overall population during follow‐up. Pneumomediastinum/pneumothorax occurred significantly more frequently in patients with PACs(+) than in those without (76.5% vs. 37.5%; P = 0.012). PACs(+) was the only significant risk factor for pneumomediastinum/pneumothorax. Conclusions Our data showed that PACs commonly occur in patients with PPFE, and most PACs were para‐carinal air cysts. Additionally, PACs(+) was a significant risk factor for pneumomediastinum/pneumothorax; therefore, clinicians should be more aware of these complications during follow‐up examination, particular in PACs(+) patients with PPFE

    Upper Extremity Skeletal Muscle Mass Asymmetry Exacerbated by Shoulder Imbalance in Lenke1A Adolescent Idiopathic Scoliosis

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    Limb muscle strength asymmetry affects many physical abilities. The present study (1) quantified limb muscle asymmetry in patients with adolescent idiopathic scoliosis (AIS); (2) compared AIS patients with major thoracolumbar/lumbar (TL/L) or major thoracic (MT) curves; (3) examined correlations between limb muscle asymmetry and radiographic parameters. Patients with AIS with major TL/L curves (Lenke type 5C) and MT curves (Lenke Type 1A) who underwent posterior spinal fusion at our university hospitals were included. Patients with left hand dominance were excluded. Body composition was measured using whole-body dual-energy X-ray absorptiometry and asymmetry of left and right side skeletal muscles were evaluated. Upper extremity skeletal muscles on the dominant side were significantly larger than those on the nondominant side in both Lenke1A and 5C groups. The asymmetry of upper extremity skeletal muscles was significantly greater in the Lenke1A group than in the Lenke5C group. Additionally, the size of the asymmetry did not correlate with the magnitude of the major curve and rotational deformation but did correlate with a right shoulder imbalance in the Lenke1A group. These results suggest that in AIS with a constructive thoracic curve, right shoulder imbalance is an independent risk factor for upper extremity skeletal muscle asymmetry
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