316 research outputs found
Generation of a stable pluripotent cell line from Chinese Hamster embryonic fibroblasts
Chinese hamster ovary (CHO) cells are aneuploidy and exhibit a high degree of genomic instability. Many studies having a cell line with a stable karyotype and genome structure is highly desirable. We have derived a stable cell line from Chinese hamster embryonic fibroblasts by transduction of mouse transcription factors M3O (a fusion gene which is chimeric of Oct4 and the effective transactivation domain of MyoD), Sox2, Klf4, and n-Myc using a lentivirus vector. The cells showed morphology of typical murine pluripotent stem cells, stained positively with alkaline phosphatase, expressed endogenous Sox2, Nanog and surface antigen SSEA1, resembling mouse embryonic stem cells. They maintained a normal 22, XY male karyotype. Bisulfite sequencing showed that the CpG on the promoter regions of Oct4 were highly unmethylated. Their telomerase activity was high compared to the parental Chinese hamster embryonic fibroblasts. Upon injection into mice these cells form teratoma that exhibit differentiated cell types of all three germ layer lineages. Transcriptome analysis using an expression array revealed the expression of all pluripotent marker genes and other metabolic genes that are characteristic of embryonic stem cells. The cell line thus possesses all the characteristics of an induced pluripotent cell line. Their differentiation capability toward hepatic and other lineages is currently being investigate
Recommended from our members
Fast-Response Micro-Phototransistor Based on MoS2/Organic Molecule Heterojunction
Over the past years, molybdenum disulfide (MoS2) has been the most extensively studied two-dimensional (2D) semiconductormaterial. With unique electrical and optical properties, 2DMoS2 is considered to be a promising candidate for future nanoscale electronic and optoelectronic devices. However, charge trapping leads to a persistent photoconductance (PPC), hindering its use for optoelectronic applications. To overcome these drawbacks and improve the optoelectronic performance, organic semiconductors (OSCs) are selected to passivate surface defects, tune the optical characteristics, and modify the doping polarity of 2D MoS2. Here, we demonstrate a fast photoresponse in multilayer (ML) MoS2 by addressing a heterojunction interface with vanadylphthalocyanine (VOPc) molecules. The MoS2/VOPc van der Waals interaction that has been established encourages the PPC effect in MoS2 by rapidly segregating photo-generated holes, which move away from the traps of MoS2 toward the VOPc molecules. The MoS2/VOPc phototransistor exhibits a fast photo response of less than 15 ms for decay and rise, which is enhanced by 3ordersof magnitude in comparison to that of a pristine MoS2-based phototransistor (seconds to tens of seconds). This work offers a means to realize high-performance transition metal dichalcogenide (TMD)-based photodetection with a fast response speed
Development of a Vacuum Ultra-Violet Laser-Based Angle-Resolved Photoemission System with a Super-High Energy Resolution Better Than 1 meV
The design and performance of the first vacuum ultra-violet (VUV) laser-based
angle-resolved photoemission (ARPES) system are described. The VUV laser with a
photon energy of 6.994 eV and bandwidth of 0.26 meV is achieved from the second
harmonic generation using a novel non-linear optical crystal KBe2BO3F2 (KBBF).
The new VUV laser-based ARPES system exhibits superior performance, including
super-high energy resolution better than 1 meV, high momentum resolution,
super-high photon flux and much enhanced bulk sensitivity, which are
demonstrated from measurements on a typical Bi2Sr2CaCu2O8 high temperature
superconductor. Issues and further development related to the VUV laser-based
photoemission technique are discussed.Comment: 29 pages, 10 figures, submitted to Review of Scientific Instrument
Fermi Surface and Band Renormalization in (Sr,K)FeAs Superconductor from Angle-Resolved Photoemission Spectroscopy
High resolution angle-resolved photoemission measurements have been carried
out on (Sr,K)FeAs superconductor (Tc=21 K). Three hole-like Fermi
surface sheets are clearly resolved for the first time around the Gamma point.
The overall electronic structure shows significant difference from the band
structure calculations. Qualitative agreement between the measured and
calculated band structure is realized by assuming a chemical potential shift of
-0.2 eV. The obvious band renormalization suggests the importance of electron
correlation in understanding the electronic structure of the Fe-based
compounds.Comment: 4 pages, 4 figure
Unusual Fermi Surface Sheet-Dependent Band Splitting in Sr2RuO4 Revealed by High Resolution Angle-Resolved Photoemission
High resolution angle-resolved photoemission measurements have been carried
out on Sr2RuO4. We observe clearly two sets of Fermi surface sheets near the
(\pi,0)-(0,\pi) line which are most likely attributed to the surface and bulk
Fermi surface splitting of the \beta band. This is in strong contrast to the
nearly null surface and bulk Fermi surface splitting of the \alpha band
although both have identical orbital components. Extensive band structure
calculations are performed by considering various scenarios, including
structural distortion, spin-orbit coupling and surface ferromagnetism. However,
none of them can explain such a qualitative difference of the surface and bulk
Fermi surface splitting between the \alpha and \beta sheets. This unusual
behavior points to an unknown order on the surface of Sr2RuO4 that remains to
be uncovered. Its revelation will be important for studying and utilizing novel
quantum phenomena associated with the surface of Sr2RuO4 as a result of its
being a possible p-wave chiral superconductor and a topological superconductor.Comment: 13 pages, 4 figure
- …