242 research outputs found
Bi- or ter-pyridine tris-substituted benzenes as electron-transporting materials for organic light-emitting devices
We demonstrated that 1,3,5-tris([2',2 '']bipyridin-6'-yl) benzene (BpyB) and 1,3,5-tris([ 2',2 '',6 '',2''']terpyridin-6'-yl)benzene (TpyB) are good electron-transport (ET) layer materials for organic light-emitting devices (OLEDs). The new materials exhibit high electron mobilities of around 10 (4) cm(2) V (1) s (1), and OLEDs comprising the materials operate at lower voltage than the OLEDs with tris(8-hydroxyquinolinato) aluminum (Alq) as an ET material. The new materials are also useful for phosphorescent OLEDs in blue-, green-, and red-light-emitting devices, where they function as both electron-transporting and hole-blocking materials. Phosphorescent OLEDs with the new materials operate at lower voltage (while maintaining comparable external quantum efficiencies of electroluminescence) than does the corresponding reference device with bathocuproine/Alq as electron-transporting and hole-blocking layers.ArticleORGANIC ELECTRONICS. 11(12):1966-1973 (2010)journal articl
Bipyridyl-substituted benzo[1,2,3]triazoles as a thermally stable electron transporting material for organic light-emitting devices
We developed new electron-transporting materials (ETMs) for organic light-emitting devices (OLEDs) based on benzo[1,2,3] triazole and two bipyridines. Four derivatives based on the same skeleton were synthesized with four different substituents: phenyl (BpyBTAZ-Ph), biphenyl (-BP), m-terphenyl (-mTP), and o-terphenyl (-oTP). These BpyBTAZ compounds have good thermal stabilities, and their decomposition temperatures were greater than 410 degrees C, which is significantly higher than that of tris(8-quinolinolato) aluminium (Alq), the conventional OLED material. BpyBTAZ compounds show preferable amorphous nature, and moreover, the glass transition temperatures (T(g)s) of both BpyBTAZ-TP compounds exceed 100 degrees C. Furthermore, BpyBTAZ-BP exhibits no melting point and is fully amorphous. The electron affinities of the materials are as large as 3.3 eV and their electron mobility is sufficiently high. These characteristics accounted for a reduction in the operational voltage of OLEDs with BpyBTAZ compounds compared with the reference device with Alq as an ETM. Specifically, the electron mobility of all the BpyBTAZ compounds exceeds 1 x 10(-4) cm(2) V(-1) s(-1) at an electric field of 1 MV cm(-1). In addition, it was revealed that both BpyBTAZ-TP-based devices showed longer luminous lifetimes and smaller voltage increases during continuous operation at 50 mA cm(-2), compared with the Alq reference device.ArticleJOURNAL OF MATERIALS CHEMISTRY. 21(32):11791-11799 (2011)journal articl
HLA-Haploidentical Peripheral Blood Stem Cell Transplantation with Post-Transplant Cyclophosphamide after Busulfan-Containing Reduced-Intensity Conditioning
AbstractAllogeneic hematopoietic stem cell transplantation (allo-SCT) using post-transplant cyclophosphamide (PTCy) is increasingly performed. We conducted a multicenter phase II study to evaluate the safety and efficacy of PTCy-based HLA-haploidentical peripheral blood stem cell transplantation (PTCy-haploPBSCT) after busulfan-containing reduced-intensity conditioning. Thirty-one patients were enrolled; 61% patients were not in remission and 42% patients had a history of prior allo-SCT. Neutrophil engraftment was achieved in 87% patients with a median of 19 days. The cumulative incidence of grades II to IV and III to IV acute graft-versus-host disease (GVHD) and chronic GVHD at 1 year were 23%, 3%, and 15%, respectively. No patients developed severe chronic GVHD. Day 100 nonrelapse mortality (NRM) rate was 19.4%. Overall survival, relapse, and disease-free survival rates were 45%, 45%, and 34%, respectively, at 1 year. Subgroup analysis showed that patients who had a history of prior allo-SCT had lower engraftment, higher NRM, and lower overall survival than those not receiving a prior allo-SCT. Our results suggest that PTCy-haploPBSCT after busulfan-containing reduced-intensity conditioning achieved low incidences of acute and chronic GVHD and NRM and stable donor engraftment and low NRM, particularly in patients without a history of prior allo-SCT
Essential Role of the Zinc Transporter ZIP9/SLC39A9 in Regulating the Activations of Akt and Erk in B-Cell Receptor Signaling Pathway in DT40 Cells
The essential trace element zinc is important for all living organisms. Zinc functions not only as a nutritional factor, but also as a second messenger. However, the effects of intracellular zinc on the B cell-receptor (BCR) signaling pathway remain poorly understood. Here, we present data indicating that the increase in intracellular zinc level induced by ZIP9/SLC39A9 (a ZIP Zrt-/Irt-like protein) plays an important role in the activation of Akt and Erk in response to BCR activation. In DT40 cells, the enhancement of Akt and Erk phosphorylation following BCR activation requires intracellular zinc. To clarify this event, we used chicken ZnT5/6/7-gene-triple-knockout DT40 (TKO) cells and chicken Zip9-knockout DT40 (cZip9KO) cells. The levels of Akt and ERK phosphorylation significantly decreased in cZip9KO cells. In addition, the enzymatic activity of protein tyrosine phosphatase (PTPase) increased in cZip9KO cells. These biochemical events were restored by overexpressing the human Zip9 (hZip9) gene. Moreover, we found that the increase in intracellular zinc level depends on the expression of ZIP9. This observation is in agreement with the increased levels of Akt and Erk phosphorylation and the inhibition of total PTPase activity. We concluded that ZIP9 regulates cytosolic zinc level, resulting in the enhancement of Akt and Erk phosphorylation. Our observations provide new mechanistic insights into the BCR signaling pathway underlying the regulation of intracellular zinc level by ZIP9 in response to the BCR activation
Extracellular-to-intracellular water ratios are associated with functional disability levels in patients with knee osteoarthritis: results from the Nagahama Study.
INTRODUCTION/OBJECTIVES: To test the hypothesis that greater extracellular-to-intracellular water (ECW/ICW) ratios in lower-limb muscles are associated with worsened functional abilities in patients with knee osteoarthritis (OA). METHODS: We analyzed data from 787 participants (82.2% female; mean age, 69.6 ± 5.3 years) from the Nagahama Prospective Cohort who were ≥60 years old and had radiographically confirmed bilateral knee OA. The Knee Scoring System (KSS) was used to assess functional abilities. Lower-limb ECW/ICW ratios and skeletal mass index values were determined with multi-frequency bioelectrical impedance analysis (BIA). Multiple linear regression analysis was used to test for associations between ECW/ICW ratios and functional abilities. Subgroup analyses based on OA severities and symptomaticity were also conducted. RESULTS: Increased ECW/ICW ratios were associated with a 4.38-point decrease in the KSS function scores (95% confidence interval [CI], 3.15-5.62 points) after adjusting for covariates. This association varied according to the degree of knee symptoms, especially in individuals with radiologically mild OA. ECW/ICW ratios in individuals with asymptomatic mild OA were associated with a 2.14-point decrease in the KSS function score (95% CI, 0.32-3.96 points), whereas those in individuals with severe symptomatic mild OA were associated with a 6.16-point decrease (95% CI, 2.13-10.19 points). CONCLUSIONS: Our findings indicate that higher ECW/ICW ratios are associated with greater functional disability in patients with knee OA. Therefore, ECW/ICW ratio measurements with multi-frequency BIA can serve as valuable indicators for functional disability in patients with knee OA. Key Points • Higher extracellular-to-intracellular water (ECW/ICW) ratios are associated with greater functional disability levels in patients with knee osteoarthritis (OA). • ECW/ICW ratios are useful clinical signs as a biomarker for poor functional abilities in patients with knee OA
A Tunable Monolithic SQUID in Twisted Bilayer Graphene
Magic-angle twisted bilayer graphene (MATBG) hosts a number of correlated
states of matter that can be tuned by electrostatic doping. Superconductivity
has drawn considerable attention and the mechanism behind it is a topic of
active discussion. MATBG has been experimentally characterized by numerous
transport and scanning-probe experiments. The material has also emerged as a
versatile platform for superconducting electronics, as proven by the
realization of monolithic Josephson junctions. However, even though
phase-coherent phenomena have been measured, no control of the superconducting
phase has been demonstrated so far. Here, we present a Superconducting Quantum
Interference Device (SQUID) in MATBG, where the superconducting phase
difference is controlled through the magnetic field. We observe
magneto-oscillations of the critical current, demonstrating long-range
coherence agreeing with an effective charge of 2e for the superconducting
charge carriers. We tune to both asymmetric and symmetric SQUID configurations
by electrostatically controlling the critical currents through the junctions.
With this tunability, we study the inductances in the device, finding values of
up to 2{\mu}H. Furthermore, we directly observe the current-phase relation of
one of the Josephson junctions of the device. Our results show that
superconducting devices in MATBG can be scaled up and used to reveal properties
of the material. We expect this to foster a more systematic realization of
devices of this type, increasing the accuracy with which microscopic
characteristics of the material are extracted. We also envision more complex
devices to emerge, such as phase-slip junctions or high kinetic inductance
detectors.Comment: Supplementary Information is included in the .pd
Bi- or ter-pyridine tris-substituted benzenes as electron-transporting materials for organic light-emitting devices
We demonstrated that 1,3,5-tris([2',2 '']bipyridin-6'-yl) benzene (BpyB) and 1,3,5-tris([ 2',2 '',6 '',2''']terpyridin-6'-yl)benzene (TpyB) are good electron-transport (ET) layer materials for organic light-emitting devices (OLEDs). The new materials exhibit high electron mobilities of around 10 (4) cm(2) V (1) s (1), and OLEDs comprising the materials operate at lower voltage than the OLEDs with tris(8-hydroxyquinolinato) aluminum (Alq) as an ET material. The new materials are also useful for phosphorescent OLEDs in blue-, green-, and red-light-emitting devices, where they function as both electron-transporting and hole-blocking materials. Phosphorescent OLEDs with the new materials operate at lower voltage (while maintaining comparable external quantum efficiencies of electroluminescence) than does the corresponding reference device with bathocuproine/Alq as electron-transporting and hole-blocking layers.ArticleORGANIC ELECTRONICS. 11(12):1966-1973 (2010)journal articl
Tunable quantum interferometer for correlated moir\'e electrons
Magic-angle twisted bilayer graphene (MATBG) can host an intriguing variety
of gate-tunable correlated states, including superconducting and correlated
insulator states. Junction-based superconducting devices, such as Josephson
junctions and SQUIDs, have been introduced recently and enable the exploration
of the charge, spin, and orbital nature of superconductivity and the coherence
of moir\'e electrons in MATBG. However, complementary fundamental coherence
effects - in particular, the Little-Parks effect in a superconducting and the
Aharonov-Bohm effect in a normal conducting ring - remained to be observed.
Here, we report the observation of both these phenomena in a single
gate-defined ring device where we can embed a superconducting or normal
conducting ring in a correlated or band insulator. We directly observe the
Little-Parks effect in the superconducting phase diagram as a function of
density and magnetic field, confirming the effective charge of . By
measuring the Aharonov-Bohm effect, we find that in our device, the coherence
length of normal conducting moir\'e electrons exceeds a few microns at 50 mK.
Surprisingly, we also identify a regime characterized by -periodic
oscillations but with superconductor-like nonlinear transport. Taken together,
these experiments establish a novel device platform in MATBG, and more
generally in tunable 2D materials, to unravel the nature of superconductivity
and other correlated quantum states in these materials
High mobility transport in isotopically-enriched C and C exfoliated graphene
Graphene quantum dots are promising candidates for qubits due to weak
spin-orbit and hyperfine interactions. The hyperfine interaction, controllable
via isotopic purification, could be the key to further improving the coherence.
Here, we use isotopically enriched graphite crystals of both C and
C grown by high-pressure-high-temperature method to exfoliate graphene
layers. We fabricated Hall bar devices and performed quantum transport
measurements, revealing mobilities exceeding and a
long mean free path of microns, which are as high as natural graphene.
Shubnikov-de Haas oscillations, quantum Hall effect up to the filling factor of
one, and Brown-Zak oscillations due to the alignment of hBN and graphene are
observed thanks to the high mobility. These results constitute a material
platform for physics and engineering of isotopically-enriched graphene qubits.Comment: 6 pages, 2 figure
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