161 research outputs found

    Efficient construction of the hexacyclic ring core of palau'amine : the pKa concept for proceeding with unfavorable equilibrium reactions

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    Palau'amine has received a great deal of attention as an attractive synthetic target due to its intriguing molecular architecture and significant immunosuppressive activity, and we achieved its total synthesis in 2015. However, the synthesized palau'amine has not been readily applicable to the mechanistic study of immunosuppressive activity, because it requires 45 longest linear steps from a commercially available compound. Here, we report the short-step construction of the ABCDEF hexacyclic ring core of palau'amine. The construction of the CDE tricyclic ring core in a single step is achieved by our pKa concept for proceeding with unfavorable equilibrium reactions, and a palau'amine analog without the aminomethyl and chloride groups is synthesized in 20 longest linear steps from the same starting material. The palau'amine analog is confirmed to retain the immunosuppressive activity. The present synthetic approach for a palau'amine analog has the potential for use in the development of palau'amine probes for mechanistic elucidation

    Crossover from coherent to incoherent scattering in spin-orbit dominated Sr2IrO4

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    Strong spin-orbit interaction in the two dimensional compound Sr2IrO4 leads to the formation of Jeff=1/2 isospins with unprecedented dynamics. In Raman scattering a continuum attributed to double spin scattering is observed. With higher excitation energy of the incident Laser this signal crosses over to an incoherent background. The characteristic energy scale of this cross over is identical to that of intensity resonance effects in phonon scattering. It is related to exciton-like orbital excitations that are also evident in resonant X-Ray scattering. The crossover and evolution of incoherent excitations are proposed to be due to their coupling to spin excitations. This signals a spin-orbit induced entanglement of spin, lattice and charge degrees of freedoms in Sr2IrO4.Comment: 20 pages, 7 figure

    Magnetic Phase Diagram of Ce1-xErxAl2 intermetallic compounds

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    The magnetic and thermal properties of Ce1−xErxAl2 compounds have been studied using electrical resistivity and magnetic susceptibility measurements. The magnetic ordering temperature continuously changes with a change from antiferro-magnetism (CeAl2) to ferro-magnetism (ErAl2) appears. The magnetic ordering temperature is continuously changed as a function of Er concentration x. A spin glass behavior was found between x = 0.08 and 0.4. The magnetic phase diagram was compiled as a function of x.Embargo Period 12 month

    Thermal and magnetic properties in Ce1-xErxAl2 intermetallic compounds

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    The magnetic and thermal properties of Ce1−xErxAl2 compounds have been studied using specific heat, dc magnetization, and ac susceptibility measurements. All these compounds are isomorphic with the MgCu2 Laves phase, and the lattice parameter decreases almost linearly with the increasing Er concentration x. The dc magnetic susceptibility follows the Curie–Weiss law, and the Weiss temperature continuously changes from Θ = −24 K for x = 0 to Θ = 15 K for x = 1, indicating a change from antiferro-magnetism to ferromagnetism. Θ changes from negative to positive at around x = 0.2 where where a field-induced metamagnetic transition disappears. The magnetic ordering state continuously changes with the change in x from antiferromagnetic to ferromagnetic through a spin-glass-like behavior.Embargo Period 12 month

    The Effects of Chlormadinone Acetate on Lower Urinary Tract Symptoms and Erectile Functions of Patients with Benign Prostatic Hyperplasia: A Prospective Multicenter Clinical Study

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    Purpose. To evaluate the effects of chlormadinone acetate (CMA), progesterone-derived antiandrogen, on lower urinary tract symptoms (LUTS) and erectile functions of benign prostatic hyperplasia (BPH). Methods. A multicenter, single-cohort prospective study was conducted. A total of 114 patients received CMA for 16 weeks. The endpoints were changes in International Prostate Symptom Scores (IPSS), IPSS-QOL, International Index of Erectile Function-5, Qmax prostate volume, and residual urine volume. Results. Significant improvements were observed in IPSS from week 8 to week 48 (32 weeks after treatment). IPSS-QOL improvements were also significant from week 8 to week 48. Qmax increased to a maximum at Week 16 and remained elevated throughout the study. Moreover, a decrease of 25% in prostate volume was observed at Week 16. IPSS, QOL, and Qmax changes during the study were not different between the previously treated and untreated patients. IPSS storage subscore changes differed between the age groups. Few severe adverse reactions were observed, except for erectile dysfunction. Conclusions. CMA rapidly and significantly reduced prostate volume and improved voiding and storage symptoms and QOL. Our results suggest that CMA is safe and beneficial, especially for elderly patients with LUTS associated with BPH

    Highly Stretchable Stress-Strain Sensor from Elastomer Nanocomposites with Movable Cross-links and Ketjenblack

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    Practical applications like very thin stress-strain sensors require high strength, stretchability, and conductivity, simultaneously. One of the approaches is improving the toughness of the stress-strain sensing materials. Polymeric materials with movable cross-links in which the polymer chain penetrates the cavity of cyclodextrin (CD) demonstrate enhanced strength and stretchability, simultaneously. We designed two approaches that utilize elastomer nanocomposites with movable cross-links and carbon filler (ketjenblack, KB). One approach is mixing SC (a single movable cross-network material), a linear polymer (poly(ethyl acrylate), PEA), and KB to obtain their composite. The electrical resistance increases proportionally with tensile strain, leading to the application of this composite as a stress- strain sensor. The responses of this material are stable for over 100 loading and unloading cycles. The other approach is a composite made with KB and a movable cross-network elastomer for knitting dissimilar polymers (KP), where movable cross-links connect the CD-modified polystyrene (PSCD) and PEA. The obtained composite acts as a highly sensitive stress-strain sensor that exhibits an exponential increase in resistance with increasing tensile strain due to the polymer dethreading from the CD rings. The designed preparations of highly repeatable or highly responsive stress-strain sensors with good mechanical properties can help broaden their application in electrical devices

    IMMUNOMODULATIVE EFFECTS OF BOVINE IMMUNODEFICIENCY-LIKE VIRUS (BIV)-INFECTION AND MIXED INFECTION OF BIV AND BOVINE LEUKEMIA VIRUS ON SHEEP

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    Experimental bovine immunodeficiency-like virus (BIV)-infection and mixed infection of BIV and bovine leukemia virus (BLV) were performed on sheep. BIV proviral DNA and anti-BIV antibodies were persistently detected in all BIV-inoculated sheep. A slight increase in lymphocyte counts was observed in BIV-infected sheep, but the percentages of CD4^+ and CD8^+ cells in sheep peripheral blood mononuclear cells (PBMCs) were not significantly changed. A transient decrease in lymphocyte blastogenic response to concanavalin A was observed in two of three BIV-infected sheep at 3-6 months after inoculation. From 6 months after BLV-inoculation to sheep which were previously infected with BIV, the numbers of lymphocytes expressing a tumor-associated antigen (TAA) of bovine leukosis were increased compared to those of a sheep inoculated with BLV alone. The BLV titers in PBMCs and the antibody titers against BLV from sheep infected with both BIV and BLV were higher than those of a sheep inoculated with BLV alone

    Non-equilibrium Thermodynamic Model of a Highly Permeable Forward Osmosis Membrane

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