http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
A FIXED POINT THEOREM REVISITED
Kirk, W.A,Kang, B.G 대한수학회 1997 대한수학회지 Vol.34 No.2
In this paper we obtain an abstract formulation of a fixed point theorem for nonexpansive mappings. Our theorem is a non-metric version of Kirk's original theorem.
Kirk Vance,Matthew Aguayo,Akash Dakhane,Deepak Ravikumar,Jitendra Jain,Narayanan Neithalath 한국콘크리트학회 2014 International Journal of Concrete Structures and M Vol.8 No.4
Alkali-activated slag concretes are being extensively researched because of its potential sustainability-related benefits. For such concretes to be implemented in large scale concrete applications such as infrastructural and building elements, it is essential to understand its early and long-term performance characteristics vis-a`-vis conventional ordinary portland cement (OPC) based concretes. This paper presents a comprehensive study of the property and performance features including early-age isothermal calorimetric response, compressive strength development with time, microstructural features such as the pore volume and representative pore size, and accelerated chloride transport resistance of OPC and alkali-activated binder systems. Slag mixtures activated using sodium silicate solution (SiO₂-to-Na₂O ratio or Ms of 1?2) to provide a total alkalinity of 0.05 (Na₂O-tobinder ratio) are compared with OPC mixtures with and without partial cement replacement with Class F fly ash (20 % by mass) or silica fume (6 % by mass). Major similarities are noted between these binder systems for: (1) calorimetric response with respect to the presence of features even though the locations and peaks vary based on Ms, (2) compressive strength and its development, (3) total porosity and pore size, and (4) rapid chloride permeability and non-steady state migration coefficients. Moreover, electrical impedance based circuit models are used to bring out the microstructural features (resistance of the connected pores, and capacitances of the solid phase and pore-solid interface) that are similar in conventional OPC and alkali-activated slag concretes. This study thus demonstrates that performance-equivalent alkali-activated slag systems that are more sustainable from energy and environmental standpoints can be proportioned.
Effect of chromatin modifiers on the plasticity and immunogenicity of small-cell lung cancer
Kirk Nicole A.,Kim Kee-Beom,Park Kwon-Sik 생화학분자생물학회 2022 Experimental and molecular medicine Vol.54 No.-
Tumor suppressor genes (TSGs) are often involved in maintaining homeostasis. Loss of tumor suppressor functions causes cellular plasticity that drives numerous types of cancer, including small-cell lung cancer (SCLC), an aggressive type of lung cancer. SCLC is largely driven by numerous loss-of-function mutations in TSGs, often in those encoding chromatin modifiers. These mutations present a therapeutic challenge because they are not directly actionable. Alternatively, understanding the resulting molecular changes may provide insight into tumor intervention strategies. We hypothesize that despite the heterogeneous genomic landscape in SCLC, the impacts of mutations in patient tumors are related to a few important pathways causing malignancy. Specifically, alterations in chromatin modifiers result in transcriptional dysregulation, driving mutant cells toward a highly plastic state that renders them immune evasive and highly metastatic. This review will highlight studies in which imbalance of chromatin modifiers with opposing functions led to loss of immune recognition markers, effectively masking tumor cells from the immune system. This review also discusses the role of chromatin modifiers in maintaining neuroendocrine characteristics and the role of aberrant transcriptional control in promoting epithelial-to-mesenchymal transition during tumor development and progression. While these pathways are thought to be disparate, we highlight that the pathways often share molecular drivers and mediators. Understanding the relationships among frequently altered chromatin modifiers will provide valuable insights into the molecular mechanisms of SCLC development and progression and therefore may reveal preventive and therapeutic vulnerabilities of SCLC and other cancers with similar mutations.
Novel Natural Product Modulators of Cancer Targets, Processes, and Phenotypes
( Kirk R. Gustafson ) 전남대학교 약품개발연구소 2016 약품개발연구지 Vol.25 No.-
The NCI`s Natural Products Repository contains>220,000 extracts from taxonomically diverse marine organisms, terrestrial palnts, and microbial isolates. These extracts represent a valuable source of chemical diversity for both phenotypic and molecularly targeted high-throughput screening applications. The Molecular Targets Laboratory has successfully combined assay development experience, high-throughput screening capabilities, and natural products chemistry expertise to evaluate these extracts. Assay-guided fractionation of active extracts has provided an array of bioactive compounds that span many different structural classes. Recently, the extracts of several marine invertebrate animals have provided new heterocyclic metabolites that block activation of the HIF-1a transcription factor. These compounds represent a new structural class of alkaloid comprised of novel fused ring systems and unusual heteroatom functionality. The structural elucidation challenges associated with these proton-deficient alkaloid structures will be highlighted, along with some spectroscopic and computational methods to help address these issues. Additional new metabolites that target MALT1 protease, B-Raf kinase, and other cancer-associated targets will be described. The combination of a large, diverse library of natural product samples and new cancer-related screening platforms, provides a valuable resource for discovery of novel compounds that can serve as biological probes or potential anticancer drug development leads.