340 research outputs found
Physical properties of transparent perovskite oxides (Ba,La)SnO3 with high electrical mobility at room temperature
Transparent electronic materials are increasingly in demand for a variety of
optoelectronic applications. BaSnO3 is a semiconducting oxide with a large band
gap of more than 3.1 eV. Recently, we discovered that La doped BaSnO3 exhibits
unusually high electrical mobility of 320 cm^2(Vs)^-1 at room temperature and
superior thermal stability at high temperatures [H. J. Kim et al. Appl. Phys.
Express. 5, 061102 (2012)]. Following that work, we report various physical
properties of (Ba,La)SnO3 single crystals and films including
temperature-dependent transport and phonon properties, optical properties and
first-principles calculations. We find that almost doping-independent mobility
of 200-300 cm^2(Vs)^-1 is realized in the single crystals in a broad doping
range from 1.0x10^19 to 4.0x10^20 cm^-3. Moreover, the conductivity of ~10^4
ohm^-1cm^-1 reached at the latter carrier density is comparable to the highest
value. We attribute the high mobility to several physical properties of
(Ba,La)SnO3: a small effective mass coming from the ideal Sn-O-Sn bonding,
small disorder effects due to the doping away from the SnO2 conduction channel,
and reduced carrier scattering due to the high dielectric constant. The
observation of a reduced mobility of ~70 cm^2(Vs)^-1 in the film is mainly
attributed to additional carrier-scatterings which are presumably created by
the lattice mismatch between the substrate SrTiO3 and (Ba,La)SnO3. The main
optical gap of (Ba,La)SnO3 single crystals remained at about 3.33 eV and the
in-gap states only slightly increased, thus maintaining optical transparency in
the visible region. Based on these, we suggest that the doped BaSnO3 system
holds great potential for realizing all perovskite-based, transparent
high-frequency high-power functional devices as well as highly mobile
two-dimensional electron gas via interface control of heterostructured films.Comment: 31 pages, 7 figure
Enabling High‐Stability of Aqueous‐Processed Nickel‐Rich Positive Electrodes in Lithium Metal Batteries
Lithium batteries occupy the large-scale electric mobility market raising concerns about the environmental impact of cell production, especially regarding the use of poly(vinylidene difluoride) (teratogenic) and N-methyl-2-pyrrolidone (NMP, harmful). To avoid their use, an aqueous electrode processing route is utilized in which a water-soluble hybrid acrylic-fluoropolymer together with sodium carboxymethyl cellulose is used as binder, and a thin phosphate coating layer is in situ formed on the surface of the nickel-rich cathode during electrode processing. The resulting electrodes achieve a comparable performance to that of NMP-based electrodes in conventional organic carbonate-based electrolyte (LP30). Subsequently, an ionic liquid electrolyte (ILE) is employed to replace the organic electrolyte, building stable electrode/electrolyte interphases on the surface of the nickel-rich positive electrode (cathode) and metallic lithium negative electrode (anode). In such ILE, the aqueously processed electrodes achieve high cycling stability with a capacity retention of 91% after 1000 cycles (20 °C). In addition, a high capacity of more than 2.5 mAh cm is achieved for high loading electrodes (≈15 mg cm) by using a modified ILE with 5% vinylene carbonate additive. A path to achieve environmentally friendly electrode manufacturing while maintaining their outstanding performance and structural integrity is demonstrated
High Mobility in a Stable Transparent Perovskite Oxide
We discovered that La-doped BaSnO3 with the perovskite structure has an
unprecedentedly high mobility at room temperature while retaining its optical
transparency. In single crystals, the mobility reached 320 cm^2(Vs)^-1 at a
doping level of 8x10^19 cm^-3, constituting the highest value among
wide-band-gap semiconductors. In epitaxial films, the maximum mobility was 70
cm^2(Vs)^-1 at a doping level of 4.4x10^20 cm^-3. We also show that resistance
of (Ba,La)SnO3 changes little even after a thermal cycle to 530 Deg. C in air,
pointing to an unusual stability of oxygen atoms and great potential for
realizing transparent high-frequency, high-power functional devices.Comment: 15 pages, 3 figure
Idiopathic retroperitoneal fibrosis associated with Hashimoto's thyroiditis in a patient with a single functioning kidney
AbstractRetroperitoneal fibrosis (RPF) is a rare disease characterized by the presence of fibroinflammatory tissue around the abdominal aorta and ureteral entrapment in most cases. Idiopathic RPF is frequently reported in association with autoimmune diseases; however, there have been few reports of idiopathic RPF associated with Hashimoto's thyroiditis. Here, we report a case of idiopathic RPF with Hashimoto's thyroiditis in a patient with a single functioning kidney, which was successfully treated by corticosteroid therapy and transient intraureteral stent insertion with a double-J catheter
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Utility of targeted deep sequencing for detecting circulating tumor DNA in pancreatic cancer patients.
Targeted deep sequencing across broad genomic regions has been used to detect circulating tumor DNA (ctDNA) in pancreatic ductal adenocarcinoma (PDAC) patients. However, since most PDACs harbor a mutation in KRAS, sequencing of broad regions needs to be systemically compared to analyzing only KRAS mutations for PDAC. Using capture-based targeted deep sequencing, we detected somatic tumor mutations in 17 fine needle aspiration biopsy and 69 longitudinal cell-free DNA (cfDNA) samples from 17 PDAC patients. KRAS mutations were detected in 10 out of 17 pretreatment patient plasma samples. Next, interrogation of genetic alterations in matched primary tumor samples detected ctDNA in 12 of 17 pretreatment plasma samples and cfDNA sequencing across the 83 target genes identified ctDNA in 15 of 17 cases (88.2% sensitivity). This improved sensitivity of ctDNA detection resulted in enhanced tumor burden monitoring when we analyzed longitudinal plasma samples. We found that cfDNA sequencing detected the lowest mutant allelic fractions and number of variants when complete response or partial response to chemotherapy was achieved. We demonstrated that ctDNA levels measured by targeted deep sequencing sensitively indicate the presence of cancer and correlate well with clinical responses to therapy and disease progression in PDAC patients
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