Giant Magnetoresistance Effect in the Metal-Insulator Transition of Pyrochlore Oxide Nd2Ir2O7

We investigated the magnetoresistance (MR) effect of the pyrochlore oxide Nd2Ir2O7, which shows a metal-insulator transition at T_MI =33 K. A small positive MR effect was observed in the metallic state above T_MI, while a large negative MR effect was observed in the insulating state below T_MI . MR effects exceeding 3000% were found at 1 K at a field of 9 T. As a result, we confirmed the crossover from the insulating state to a state with a small or partial band gap in a field up to 56 T. Furthermore, from the MR effect in Eu2Ir2O7 (T_MI = 120 K) and Gd$_2$Ir$_2$O$_7$ (T_MI = 127 K), we revealed that the large negative MR effect of the pyrochlore iridate Ln2Ir2O7 depends on the magnetism of the lanthanide Ln^{3+} ion. The d-f interaction plays a significant role in the large negative MR effect in the insulating state.Comment: 10 pages, 4 figure

Metal–Insulator Transitions in Pyrochlore Oxides Ln2Ir2O7

We report the physical properties of Ln2Ir2O7 (Ln = Nd, Sm, Eu, Gd, Tb, Dy, and Ho), which exhibit metal-insulator transitions (MITs) at different temperatures. The transition temperature TMI increases with a reduction in the ionic radius of Ln. The ionic radius　boundary for MITs in Ln2Ir2O7 lies between Ln = Pr and Nd. MITs in Ln2Ir2O7 have some common features. They are second-order transitions. Under the field cool condition, a weak ferromagnetic component (»10−3 μB/f.u.) caused by Ir 5d electrons is observed below TMI.The entropy associated with MITs for Ln = Nd, Sm, and Eu is estimated to be 0.47, 2.0, and 1.4 J/K mole, respectively. The change in entropy is much smaller than 2R ln 2 [11.5 J /K mole] expected in a magnetic transition due to localized moments of S = 1/2. The feature of continuous MITs in Ln2Ir2O7 is discussed

Small-cell lung cancer with a rare epidermal growth factor receptor gene mutation showing “wax-and-wane” transformation

BACKGROUND: Small-cell lung cancer with epidermal growth factor receptor (EGFR) gene mutation typically manifests as a transformation occurring after EGFR tyrosine kinase inhibitor therapy for adenocarcinoma with EGFR mutation, whereas primary small-cell lung cancer showing EGFR mutation is extremely rare. Second biopsy of EGFR-mutated tumor has been broadly recognized as necessary, but is not always performed in daily practice, mainly due to the imbalance between the potential risk of the diagnostic procedure and the therapeutic impact of the biopsy result. CASE PRESENTATION: A 70-year-old woman who had never smoked was referred to our hospital with chief complaints of cough and back pain. Transbronchial lung biopsy from the primary tumor of the left upper lobe revealed combined small-cell lung cancer and adenocarcinoma, a subtype of small-cell lung cancer. EGFR L861Q mutation was detected in both small-cell lung cancer and adenocarcinoma components. Given the staging of cT2aN3M1b (Stage IV) and histological diagnosis, first-line chemotherapy with cisplatin plus irinotecan was initiated, and partial response was achieved. Seven months after initial diagnosis, the primary tumor enlarged again, and a second biopsy from the enlarged lesion detected only adenocarcinoma with the L861Q mutation. Erlotinib was started, but multiple brain metastases and enlarged mediastinal lymph nodes subsequently appeared. Whole-brain radiation therapy was performed, and endobronchial ultrasonography-guided transbronchial biopsy from the lymph node revealed reverse transformation to small-cell lung cancer with the L861Q mutation. Amrubicin therapy achieved partial response after two cycles, with the shrinkage lasting for eight months. Serum sialyl Lewis X antigen level increased when the adenocarcinoma component was dominant, whereas plasma pro-gastrin-releasing peptide level increased when the small-cell lung cancer component became dominant. CONCLUSIONS: Transformation of the tumor correlates with the difference between small-cell lung cancer and adenocarcinoma in sensitivity to therapies, so repeated biopsies are beneficial for choosing appropriate treatments. Noninvasively obtainable parameters such as tumor markers can support the need for biopsy

Metal–Insulator Transitions in Pyrochlore Oxides Ln2Ir2O7

We report the physical properties of Ln2Ir2O7 (Ln = Nd, Sm, Eu, Gd, Tb, Dy, and Ho), which exhibit metal-insulator transitions (MITs) at different temperatures. The transition temperature TMI increases with a reduction in the ionic radius of Ln. The ionic radius　boundary for MITs in Ln2Ir2O7 lies between Ln = Pr and Nd. MITs in Ln2Ir2O7 have some common features. They are second-order transitions. Under the field cool condition, a weak ferromagnetic component (»10−3 μB/f.u.) caused by Ir 5d electrons is observed below TMI. The entropy associated with MITs for Ln = Nd, Sm, and Eu is estimated to be 0.47, 2.0, and 1.4 J/K mole, respectively. The change in entropy is much smaller than 2R ln 2 [11.5 J /K mole] expected in a magnetic transition due to localized moments of S = 1/2. The feature of continuous MITs in Ln2Ir2O7 is discussed

Surgical treatment of thoracoabdominal aortic mural and floating thrombi extending to infrarenal aorta

AbstractThe case of a 49-year-old man with thoracoabdominal aortic mural and floating thrombi extending to the infrarenal aorta and occlusion of the common iliac artery is described. He had no factors promoting thrombosis, with a history of thrombectomy of the femoral artery. The thoracoabdominal aortic thrombi were successfully removed with a Forgaty catheter through a thoracotomy under simple aortic clamping and subsequent femoro-femoral cardiopulmonary bypass. Intravascular ultrasound performed through the femoral artery after thrombectomy revealed that little mural thrombi remained and that the celiac, superior mesenteric, and bilateral renal arteries were all patent

Effect of Digestibility of Soy Protein Concentrate on Rat Nutrition(1) : Effect of Proteolytic Pretreatment of Soy Protein Concentrate on Amino Acid Pattern in Small Intestine and Activities of Enzymes related with Digestion and Metabolism of Protein

The digestion and metabolism of protein of rats fed soy protein concentrate (SP) pretreated by protease was investigated, and the nutritive value of the pretreated SP was discussed. Glutamate-pyruvate transaminase, arginase and xanthine oxidase activities in liver of rats fed heated SP are lower than those fed SP pretreated by protease and amino acid mixture simulated SP. There is more quantity of peptide in small intestine of rats fed SP pretreated by protease than that fed the amino acid mixture. In free amino acid pattern, however, no difference was shown between SP groups, but the patterns of SP groups, especially on the bases of methionine content, were different with that of amino acid mixture group. No difference is shown in the digestion and the biological values between SP groups. From these results, it was found that the pretreatment of SP by protease, which might improve the digestibility of SP, was effective for raising the availability of SP. It may be considered, furthermore, that methionine in SP is difficult to liberate in small intestine, which causes a wasteful absorption of amino acids for rat

PcpA, which is involved in the degradation of pentachlorophenol in Sphingomonas chlorophenolica ATCC39723, is a novel type of ring-cleavage dioxygenase

AbstractThe pentachlorophenol (PCP) mineralizing bacterium Sphingomonas chlorophenolica ATCC39723 degrades PCP via 2,6-dichlorohydroquinone (2,6-DCHQ). The pathway converting PCP to 2,6-DCHQ has been established previously; however, the pathway beyond 2,6-DCHQ is not clear, although it has been suggested that a PcpA plays a role in 2,6-DCHQ conversion. In this study, PcpA expressed in Escherichia coli was purified to homogeneity and shown to have novel ring-cleavage dioxygenase activity in conjunction with hydroquinone derivatives, and converting 2,6-DCHQ to 2-chloromaleylacetate