113 research outputs found
Identification and Detailed Characterization of Metal Oxide Powders as a Fundamental Chemical Product
Here we propose a method for identification and detailed characterization of metal-oxide powders with patterns of energy-resolved density of electron traps (ERDT) and conduction-band bottom (CBB) position, as a fingerprint, measured by newly developed reversed double-beam photoacoustic spectroscopy (RDB-PAS).
Keywords: Electron Traps, Photoacoustic Spectroscopy, Metal-oxide Powders, Degree of Coincidenc
Mosaic Amplification of Multiple Receptor Tyrosine Kinase Genes in Glioblastoma
SummaryTumor heterogeneity has been implicated in tumor growth and progression as well as resistance to therapy. We present an example of genetic heterogeneity in human malignant brain tumors in which multiple closely related driver genes are amplified and activated simultaneously in adjacent intermingled cells. We have observed up to three different receptor tyrosine kinases (EGFR, MET, PDGFRA) amplified in single tumors in different cells in a mutually exclusive fashion. Each subpopulation was actively dividing, and the genetic changes resulted in protein production, and coexisting subpopulations shared common early genetic mutations indicating their derivation from a single precursor cell. The stable coexistence of different clones within the same tumor will have important clinical implications for tumor resistance to targeted therapies
Molybdenum Disulfide-Coated Lithium Vanadium Fluorophosphate Anode: Experiments and First-Principles Calculations
To develop a new anode material to meet the increasing demands of lithium-ion battery, MoS2 is used for the first time to modify the C/LiVPO4F anode to improve its lithium-storage performance between 3 and 0.01 V. Morphological observations reveal that the MoS2-modified C/LiVPO4F particles (M-LVPF) are wrapped by an amorphous carbon as interlayer and layered MoS2 as external surface. Charge–discharge tests show that M-LVPF delivers a high reversible capacity of 308 mAh g−1 at 50 mA g−1. After 300 cycles at 1.0 A g−1, a capacity retention of 98.7 % is observed. Moreover, it exhibits high rate capability with a specific capacity of 199 mAh g−1 at 1.6 A g−1. Electrochemical impedance spectroscopy tests indicate that the lithium-ion diffusion and charge-exchange reaction at the surface of M-LVPF are greatly enhanced. First-principles calculations for the MoS2 (001)/C/LiVPO4F (010) system demonstrate that the absorption of MoS2 on C/LiVPO4F is exothermic and spontaneous and that the electron transfer at the MoS2-absorbed C/LiVPO4F surface is enhanced.postprin
Physics of Transport and Traffic Phenomena in Biology: from molecular motors and cells to organisms
Traffic-like collective movements are observed at almost all levels of
biological systems. Molecular motor proteins like, for example, kinesin and
dynein, which are the vehicles of almost all intra-cellular transport in
eukayotic cells, sometimes encounter traffic jam that manifests as a disease of
the organism. Similarly, traffic jam of collagenase MMP-1, which moves on the
collagen fibrils of the extracellular matrix of vertebrates, has also been
observed in recent experiments. Traffic-like movements of social insects like
ants and termites on trails are, perhaps, more familiar in our everyday life.
Experimental, theoretical and computational investigations in the last few
years have led to a deeper understanding of the generic or common physical
principles involved in these phenomena. In particular, some of the methods of
non-equilibrium statistical mechanics, pioneered almost a hundred years ago by
Einstein, Langevin and others, turned out to be powerful theoretical tools for
quantitaive analysis of models of these traffic-like collective phenomena as
these systems are intrinsically far from equilibrium. In this review we
critically examine the current status of our understanding, expose the
limitations of the existing methods, mention open challenging questions and
speculate on the possible future directions of research in this
interdisciplinary area where physics meets not only chemistry and biology but
also (nano-)technology.Comment: 33 page Review article, REVTEX text, 29 EPS and PS figure
EZH2 Codon 641 Mutations are Common in BCL2-Rearranged Germinal Center B Cell Lymphomas
Mutations at codon 641 of EZH2 are recurrent in germinal center B cell lymphomas, and the most common variants lead to altered EZH2 enzymatic activity and enhanced tri-methylation of histone H3 at lysine 27, a repressive chromatin modification. As an initial step toward screening patients for cancer genotype-directed therapy, we developed a screening assay for EZH2 codon 641 mutations amenable for testing formalin-fixed clinical specimens, based on the sensitive SNaPshot single nucleotide extension technology. We detected EZH2 mutations in 12/55 (22%) follicular lymphomas (FL), 5/35 (14%) diffuse large B cell lymphomas with a germinal center immunophenotype (GCB-DLBCL), and 2/11 (18%) high grade B cell lymphomas with concurrent rearrangements of BCL2 and MYC. No EZH2 mutations were detected in cases of Burkitt lymphoma (0/23). EZH2 mutations were frequently associated with the presence of BCL2 rearrangement (BCL2-R) in both the FL (28% of BCL-R cases versus 0% of BCL2-WT cases, p<0.05) and GCB-DLBCL groups (33% of BCL2-R cases versus 4% of BCL2-WT cases, p<0.04), and across all lymphoma types excluding BL (27% of BCL2-R cases versus 3% of BCL2-WT cases, p<0.003). We confirmed gain-of-function activity for all previously reported EZH2 codon 641 mutation variants. Our findings suggest that EZH2 mutations constitute an additional genetic “hit” in many BCL2-rearranged germinal center B cell lymphomas. Our work may be helpful in the selection of lymphoma patients for future trials of pharmacologic agents targeting EZH2 and EZH2-regulated pathways
Genome Wide DNA Copy Number Analysis of Serous Type Ovarian Carcinomas Identifies Genetic Markers Predictive of Clinical Outcome
Ovarian cancer is the fifth leading cause of cancer death in women. Ovarian cancers display a high degree of complex genetic alterations involving many oncogenes and tumor suppressor genes. Analysis of the association between genetic alterations and clinical endpoints such as survival will lead to improved patient management via genetic stratification of patients into clinically relevant subgroups. In this study, we aim to define subgroups of high-grade serous ovarian carcinomas that differ with respect to prognosis and overall survival. Genome-wide DNA copy number alterations (CNAs) were measured in 72 clinically annotated, high-grade serous tumors using high-resolution oligonucleotide arrays. Two clinically annotated, independent cohorts were used for validation. Unsupervised hierarchical clustering of copy number data derived from the 72 patient cohort resulted in two clusters with significant difference in progression free survival (PFS) and a marginal difference in overall survival (OS). GISTIC analysis of the two clusters identified altered regions unique to each cluster. Supervised clustering of two independent large cohorts of high-grade serous tumors using the classification scheme derived from the two initial clusters validated our results and identified 8 genomic regions that are distinctly different among the subgroups. These 8 regions map to 8p21.3, 8p23.2, 12p12.1, 17p11.2, 17p12, 19q12, 20q11.21 and 20q13.12; and harbor potential oncogenes and tumor suppressor genes that are likely to be involved in the pathogenesis of ovarian carcinoma. We have identified a set of genetic alterations that could be used for stratification of high-grade serous tumors into clinically relevant treatment subgroups
Modelling of redox flow battery electrode processes at a range of length scales : a review
In this article, the different approaches reported in the literature for modelling electrode processes in redox flow batteries (RFBs) are reviewed. RFB models vary widely in terms of computational complexity, research scalability and accuracy of predictions. Development of RFB models have been quite slow in the past, but in recent years researchers have reported on a range of modelling approaches for RFB system optimisation. Flow and transport processes, and their influence on electron transfer kinetics, play an important role in the performance of RFBs. Macro-scale modelling, typically based on a continuum approach for porous electrode modelling, have been used to investigate current distribution, to optimise cell design and to support techno-economic analyses. Microscale models have also been developed to investigate the transport properties within porous electrode materials. These microscale models exploit experimental tomographic techniques to characterise three-dimensional structures of different electrode materials. New insights into the effect of the electrode structure on transport processes are being provided from these new approaches. Modelling flow, transport, electrical and electrochemical processes within the electrode structure is a developing area of research, and there are significant variations in the model requirements for different redox systems, in particular for multiphase chemistries (gas–liquid, solid–liquid, etc.) and for aqueous and non-aqueous solvents. Further development is essential to better understand the kinetic and mass transport phenomena in the porous electrodes, and multiscale approaches are also needed to enable optimisation across the relevent length scales
Graphene-Based Nanocomposites for Energy Storage
Since the first report of using micromechanical cleavage method to produce graphene sheets in 2004, graphene/graphene-based nanocomposites have attracted wide attention both for fundamental aspects as well as applications in advanced energy storage and conversion systems. In comparison to other materials, graphene-based nanostructured materials have unique 2D structure, high electronic mobility, exceptional electronic and thermal conductivities, excellent optical transmittance, good mechanical strength, and ultrahigh surface area. Therefore, they are considered as attractive materials for hydrogen (H2) storage and high-performance electrochemical energy storage devices, such as supercapacitors, rechargeable lithium (Li)-ion batteries, Li–sulfur batteries, Li–air batteries, sodium (Na)-ion batteries, Na–air batteries, zinc (Zn)–air batteries, and vanadium redox flow batteries (VRFB), etc., as they can improve the efficiency, capacity, gravimetric energy/power densities, and cycle life of these energy storage devices. In this article, recent progress reported on the synthesis and fabrication of graphene nanocomposite materials for applications in these aforementioned various energy storage systems is reviewed. Importantly, the prospects and future challenges in both scalable manufacturing and more energy storage-related applications are discussed
ホニュウルイ ランホウ ケイセイ キコウ ノ カイセキ : ランホウ ハツイク ニ オケル ギャップ ケツゴウ ノ カイセキ ト マウス ハイセイカン サイボウ カラノ ランホウ ユウドウケイ ノ コウチク
博士(Doctor)バイオサイエンス(Bioscience)奈良先端科学技術大学院大学博第951号甲第951号博士(バイオサイエンス)奈良先端科学技術大学院大
Approaches to understanding the mechanism of mammalian folliculogenesis : Analysis of gap junctions in ovarian follicles, and the establishment of an in vitro system for obtaining follicles from mouse embryonic stem cells
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