Development of ultra-low mass and high-rate capable RPC based on Diamond-Like Carbon electrodes for MEG II experiment

A new type of resistive plate chamber with thin-film electrodes based on diamond-like carbon is under development for background identification in the MEG II experiment. Installed in a low-momentum and high-intensity muon beam, the detector is required to have extremely low mass and a high rate capability. A single-layer prototype detector with 2 cm $\times$ 2 cm size was constructed and evaluated to have a high rate capability of 1 MHz/cm$^2$ low-momentum muons. For a higher rate capability and scalability of the detector size, the electrodes to supply high voltage was segmented by implementing a conductive pattern on diamond-like carbon. Using the new electrodes, a four-layer prototype detector was constructed and evaluated to have a 46% detection efficiency with only a single layer active at a rate of $\cal O$(10 kHz). The result is promising to achieve the required detection efficiency of 90% at a rate of 4 MHz/cm$^2$ with all the layers active.Comment: 5 pages, 8 figures. Contribution to XVI Workshop on Resistive Plate Chambers and Related Detectors (RPC2022), September 26-30 2022. Submitted to Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipmen

Analysis of Revision Surgery of Microsurgical Lumbar Discectomy

Study DesignA retrospective study.PurposeOur objectives were to determine the association between the pathological changes of disc herniation and the interval between primary and revision surgeries and to investigate the frequency and site of the dural laceration in the primary and revision surgeries.Overview of LiteratureAmong 382 patients who underwent microsurgical lumbar discectomy, we investigated 29 who underwent revision surgery to analyze recurrent herniation pathologies and complications to determine the manner in which lumbar disc herniation can be more efficiently managed.MethodsOf 29 patients, 22 had recurrent disc herniation at the same level and site. The pathological changes associated with compression factors were classified into the following two types depending on intraoperative findings: (1) true recurrence and (2) minor recurrence with peridural fibrosis (>4 mm thickness). The sites of dural laceration were examined using video footage and operative records.ResultsThe pathological findings and days between the primary and revision surgeries showed no statistical difference (p=0.14). Analysis of multiple factors, revealed no significant difference between the primary and revision surgery groups with regard to hospital days (p=0.23), blood loss (p=0.99), and operative time (p=0.67). Dural lacerations obviously increased in the revision surgery group (1.3% vs. 16.7%, p<0.01) and were mainly located near the herniated disc in the primary surgery group and near the root shoulder in the revision surgery group, where severe fibrosis and adhesion were confirmed. To avoid dural laceration during revision surgery, meticulous decompressive manipulation must be performed around the root sleeve.ConclusionsWe recommend that meticulous epidural dissection around the scar formation must be performed during revision surgery to avoid complications

Incommensurate state in a quasi-one-dimensional S=1/2S=1/2 bond-alternating antiferromagnet with frustration in magnetic fields

We investigate the critical properties of the $S=1/2$ bond-alternating spin chain with a next-nearest-neighbor interaction in magnetic fields. By the numerical calculation and the exact solution based on the effective Hamiltonian, we show that there is a parameter region where the longitudinal incommensurate spin correlation becomes dominant around the half-magnetization of the saturation. Possible interpretations of our results are discussed. We next investigate the effects of the interchain interaction ($J^{\prime}$). The staggered susceptibility and the uniform magnetization are calculated by combining the density-matrix renormalization group method with the interchain mean-field theory. For the parameters where the dominant longitudinal incommensurate spin correlation appears in the case $J^{\prime}=0$, the staggered long-range order does not emerge up to a certain critical value of $J^{\prime}$ around the half-magnetization of the saturation. We calculate the static structure factor in such a parameter region. The size dependence of the static structure factor at $k=2k_{\rm F}$ implies that the system has a tendency to form an incommensurate long-range order around the half-magnetization of the saturation. We discuss the recent experimental results for the NMR relaxation rate in magnetic fields performed for pentafluorophenyl nitronyl nitroxide.Comment: 10 pages, 12 figures, final version, to appear in PRB vol. 70, No. 5 (2004

Dynamical structure factors of S=1/2S=1/2 two-leg spin ladder systems

We investigate dynamical properties of $S=1/2$ two-leg spin ladder systems. In a strong coupling region, an isolated mode appears in the lowest excited states, while in a weak coupling region, an isolated mode is reduced and the lowest excited states become a lower bound of the excitation continuum. We find in the system with equal intrachain and interchain couplings that due to a cyclic four-spin interaction, the distribution of the weights for the dynamical structure factor and characteristics of the lowest excited states are strongly influenced. The dynamical properties of two systems proposed for ${\rm SrCu_2O_3}$ are also discussed.Comment: 5 pages, 6 figure

Usage Survey of Personal Underfloor Air Outlet System and Thermal Environment Acceptability

This study was aimed to clarify the usage of a personal air-conditioning system and to describe the characteristics of actual worker acceptance of the thermal environment. The results showed that the usage rate of the personal air-conditioning system was 90% and that most workers were satisfied with the system’s effect. Only a few workers reported that the environment was unacceptable despite the use of the system, and they expressed this even when the temperature and humidity were within a comfortable range. It was suggested that the complaints resulted from factors such as the individual thermal histories and changes in their metabolic rate upon returning to the office after performing outdoor activities

Sunitinib Versus Sorafenib as Initial Targeted Therapy for mCC-RCC With Favorable/Intermediate Risk: Multicenter Randomized Trial CROSS-J-RCC

Purpose: The present study compared the efficacy of sunitinib and sorafenib as first-line treatment of metastatic clear cell renal cell carcinoma (mCC-RCC) with favorable or intermediate Memorial Sloan Kettering Cancer Center (MSKCC) risk. Patients and methods: Treatment-naive patients with mCC-RCC were randomized to receive open-label sunitinib followed by sorafenib (SU/SO) or sorafenib followed by sunitinib (SO/SU). The primary endpoint was first-line progression-free survival (PFS). The secondary endpoints were total PFS and overall survival (OS). Results: Of the 124 patients enrolled at 39 institutions from February 2010 to July 2012, 120 were evaluated. The median first-line PFS duration was 8.7 and 7.0 months in the SU/SO and SO/SU groups, respectively (hazard ratio [HR], 0.67; 95% confidence interval [CI], 0.42-1.08). The total PFS and OS were not significantly different between the SU/SO and SO/SU groups (27.8 and 22.6 months; HR, 0.73; 95% CI, 0.428-1.246; and 38.4 and 30.9 months; HR, 0.934; 95% CI, 0.588-1.485, respectively). The subgroup analysis revealed that the total PFS with SU/SO was superior to the total PFS with SO/SU in the patients with favorable MSKCC risk and those with Conclusions: No statistically significant differences were found in first-line PFS, total PFS, or OS between the 2 treatment arms (ClinicalTrials.gov identifier, NCT01481870)

Optical absorption spectra in SrCu_2O_3 two-leg spin ladder

We calculate the phonon-assisted optical-absorption spectra in SrCu_2O_3 two-leg spin-ladder systems. The results for two models proposed for SrCu_2O_3 are compared. In the model including the effects of a cyclic four-spin interaction, the shoulder structure appears at 978 cm^{-1} and the peak appears at 1975 cm^{-1} in the spectrum for polarization of the electric field parallel to the legs. In the other model which describes a pure two-leg ladder, the peak appears around the lower edge of the spectrum at 1344 cm^{-1}. The feature can be effective in determining the proper model for SrCu_2O_3.Comment: 5 pages, 5 figures, to appear in PRB vol. 67 (2003