Yuko Shimoji

Hopping Conductivity in CuIr2S4 Spinel Compound: I. Empirical Model for Electronic Configuration and Mechanism of Metal–Insulator Transition

Two types of spinel compound CuIr 2 S 4 samples were investigated: sample 1 was synthesized under protective Ar atmosphere to avoid contamination by oxygen, whereas sample 2 was exposed to oxygen during preparation procedure. According to the results of scanning electron microscopy, the oxygen concentration in sample 2 is 5 times higher than in sample 1. However, the metal–insulator transition (MIT) temperature is the same for both samples irrespective of oxygen concentration. The conductivity σ in the insulating phase (LIP) is proportional to exp [-( T * / T ) 1/2 ] at T ≤120 K for sample 1 and at T ≤50 K for sample 2, while in the metallic phase the resistivity ρ is proportional to the same function of σ in LIP for both samples. Temperature independent diamagnetic susceptibility and temperature dependence of thermopower suggest that this compound is not a normal activation-type semiconductor. The electronic configuration of CuIr 2 S 4 is estimated to a first approximation from the experimental results. ...

Resistivity and thermopower of CaB6 single crystal

Abstract The resistivity ρ and thermopower S of CaB6 single crystal have been measured at temperatures from 2 to 1100 K in magnetic fields up to 15 T . Temperature dependence of ρ is expressed as [ρ(T)−ρ(0)]∝ exp [−(T ∗ /T) 1/2 ] for T⩽90 K and T1.7 for 90 K ⩽T⩽1100 K , where ρ 0 =232 μΩ cm . The magnitude of ρ and S is very large suggesting thin concentration of carriers. The temperature dependence of them suggests the conduction is metallic and electron type. ρ and S can be fitted on the basis of free electron model and obtained the Fermi level is situated near the bottom of an electron band with the Fermi energy of 80 K . The experimental and fitting results show this compound is semi-metallic. No scattering anomalies in temperature dependence of ρ were observed and also no sudden change of the Fermi surface accompanied with magnetic transition in S above 100 K including the region where it might be considered to have ferromagnetic transition.

Lymphatic vessel involvement is predictive for lymph node metastasis and an important prognostic factor in endometrial cancer

BackgroundLymphovascular space involvement is reported to be an important risk factor in endometrial cancer. This study was conducted to evaluate the separate prognostic effects of lymphatic invasion and venous invasion on the outcomes of patients with endometrial cancer.MethodsFrom 2006 to 2013, 189 histologically confirmed endometrial cancer patients were examined. To study the venous invasion (v) of the endometrial cancer, Victoria blue–H&E staining—which positively stains the elastic fibers of vessels—was performed. Immunohistochemical staining with D2-40 was used to study the lymphatic invasion (ly) of the endometrial cancer.ResultsThe median age of the patients was 57 (range 25–84) years. ly(+) and/or v(+) patients were significantly more likely to present an advanced cancer stage, G3 tumor, and deep myometrial invasion than ly(−)/v(−) patients. The incidence of lymph node metastasis was high in ly(+) patients, and that of ovarian metastasis was high in v(+) patients. Lymphatic vessel invasion was significantly correlated with regional lymph node metastasis. We found a significantly higher incidence of distant metastasis in ly(+) patients. Most recurrences in ly(+)/v(−) patients occurred in lymph nodes, while those in ly(+)/v(+) patients occurred mainly at distant organs. Finally, the prognosis was significantly poorer for ly(+) patients, in whom lymphatic invasion was an independent prognostic factor along with distant metastasis.ConclusionsOur study suggests that by separately evaluating lymphatic invasion and blood vessel invasion in endometrial cancer cases, useful information for predicting lymph node metastasis and recurrence sites as well as prognostic information can be obtained.

Microsurgical lymphaticovenular anastomosis for refractory chylous ascites following para-aortic lymph nodes dissection in a patient with tubal cancer

Highlights • Postoperative chylous ascites is an important clinical issue in surgery for gynecological malignancy.• Our patient with refractory chylous ascites after surgery for tubal cancer.• She received great benefit from the microsurgical lymphaticovenular anastomosis.• The microsurgical lymphaticovenular anastomosis is the treatment of choice.• The entire procedure was performed under local anesthesia.

Concurrent weekly cisplatin versus triweekly cisplatin with radiotherapy for locally advanced squamous-cell carcinoma of the cervix: a retrospective analysis from a single institution

Objective: To compare patients with cervical cancer who were primarily treated with concurrent chemoradiotherapy (CCRT) using 20 mg m−2 CDDP for 5 days every 3 weeks with weekly regimens of 40 mg m−2. Methods: We retrospectively analyzed 185 patients with Stage IB–IVA squamous-cell carcinoma of the cervix who were treated with CCRT between 2005 and 2013 at our hospital. The CCRT regimen consisted of cisplatin (CDDP) at 20 mg m−2 for 5 days every 3 weeks or 40 mg m−2 weekly, administered concomitantly with RT. Results: The median age was 50 years (range: 22–70 years) in the triweekly group and was 50.5 years (range: 28–70 years) in the weekly group. The 5-year overall survival rate in the triweekly and weekly groups were 82.0% and 83.3%, respectively (p = 0.851); their disease-free survival rate was 79.6% and 78.1%, respectively (p = 0.672). In the triweekly group, 56 patients (50.9%) had grade 3/4 leukopenia, which was significantly higher than that of 11 patients (15%) in the weekly group (p < 0.0001). Conclusion: The weekly CDDP regimen for CCRT seems better in patients with International Federation of Gynecology and Obstetrics Stages IB–IVA squamous-cell carcinoma of the cervix. Advances in knowledge: The weekly CDDP regimen for CCRT seems better in patients with International Federation of Gynecology and Obstetrics Stages IB–IVA squamous-cell carcinoma of the cervix.

Transport Properties of Ce2Co7B3 in Magnetic Field

Thermopower S , resistivity ρ and magnetization M of Ce 2 Co 7 B 3 have been measured in magnetic fields up to 15 T at temperature range from 2 to 1000 K. The magnetic field dependence of S ( H ) and ρ( H ) changes drastically at spin-flop critical field H S = 6.0 T in 4.2 K. A very large negative magneto-resistance is observed, 35% in 15 T at 4.0 K, suggesting large spin–spin interaction between s and d electrons. Magnetic phase transitions in temperature and field are experimentally obtained, a magnetic phase diagram is established. The S ( T ) measured up to 1000 K suggests that a DOS peak exists at 250 K apart from Fermi level ( e F ) in energy. Below H S , a negative peak exists on the S ( T ) curve around 20 K, which disappears suddenly at H S . The negative peak is estimated coming from a super-zone boundary on e – k curve caused by anti-ferromagnetic periodicity. The DOS below and above H S have been estimated from experimental S ( T ) in terms of Motts two band s – d scattering model.