1,439 research outputs found
Minkowski Brane in Asymptotic dS Spacetime without Fine-tuning
We discuss properties of a 3-brane in an asymptotic 5-dimensional de-Sitter
spacetime. It is found that a Minkowski solution can be obtained without
fine-tuning. In the model, the tiny observed positive cosmological constant is
interpreted as a curvature of 5-dimensional manifold, but the Minkowski
spacetime, where we live, is a natural 3-brane perpendicular to the fifth
coordinate axis.Comment: 6 pages, Latex fil
Increased apoptosis in human knee osteoarthritis cartilage related to the expression of protein kinase B and protein kinase Cα in chondrocytes
Protein kinase B (Akt) and protein kinase CĪ± (PKCĪ±) play important roles in the regulation of cell apoptosis. The aim of this study was to investigate the expression of Akt and PKCa in chondrocytes of human knee osteoarthritic (OA) cartilage, further evaluating their role in chondrocyte apoptosis during OA progression. Human knee OA cartilages were obtained from 38 patients undergoing knee arthroplasty, which is the medium-late stage of OA. Healthy knee cartilages were obtained from 11 amputees. The samples taken from the condyle of femur were collected routinely for morphological, immunohistochemical and Western blot detection, respectively. Light microscopy and laser-scanning confocal microscopy were used for morphological observation. The optical density with computer image analysis evaluated the intensity of immunohistochemical reaction of Akt and PKCĪ± in OA cartilage. Western blot detected the protein expression levels. The results indicated that Akt and PKCa were involved in OA progression, along with the increase of cell apoptosis. In OA cartilage, Akt decreased (p < 0.05) and PKCĪ± increased (p < 0.05). There was a negative correlation and interaction between Akt and PKCĪ± (r = ā0.8). These results demonstrated that both Akt and PKCĪ± are related to increased chondrocyte apoptosis in human OA cartilage. The correlation between human OA progression, the role of Akt and PKCĪ±, and chondrocyte apoptosis allows for new therapeutic strategies to be considered
Arbitrary Optical Waveform Generation Using Planar Lightwave Circuits
Abstract-We provide an overview of the direct temporal domain approach for designing optical filters for ultrafast photonic signal processing applications. We discuss different filter designs, including lattice-form Mach-Zehnder interferometers and two-dimensional ring resonator arrays, to perform pulse repetition rate multiplication and arbitrary optical waveform generation. Simulation and experimental results are presented
Recent advances and current issues in single-cell sequencing of tumors
AbstractIntratumoral heterogeneity is a recently recognized but important feature of cancer that underlies the various biocharacteristics of cancer tissues. The advent of next-generation sequencing technologies has facilitated large scale capture of genomic data, while the recent development of single-cell sequencing has allowed for more in-depth studies into the complex molecular mechanisms of intratumoral heterogeneity. In this review, the recent advances and current challenges in single-cell sequencing methodologies are discussed, highlighting the potential power of these data to provide insights into oncological processes, from tumorigenesis through progression to metastasis and therapy resistance
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