Search results for "Matrix"
showing 10 items of 3205 documents
Autophagy Induces Expression of IL-6 in Human Periodontal Ligament Fibroblasts Under Mechanical Load and Overload and Effects Osteoclastogenesis in v…
2021
Frontiers in physiology 12, 716441 (2021). doi:10.3389/fphys.2021.716441 special issue: "Alveolar Bone: a Pivotal Role in Periodontal Disease Pathobiology and Treatment, Volume I / Fani Anagnostou, Beatriz Castaneda, Frédéric Lézot and Petros Papagerakis"
Probabilistic characterization of nonlinear systems under Poisson white noise parametric input via complex fractional moments
2014
In this paper the probabilistic characterization of a nonlinear system enforced by parametric Poissonian white noise in terms of complex fractional moments is presented. In fact the initial system driven by a parametric input could be transformed into a system with an external type of excitation through an invertible nonlinear transformation. It is shown that by using Mellin transform theorem and related concepts, the solution of the Kolmogorov-Feller equation for the system with external input may be obtained in a very easy way.
A FE-Meshless Multiscale Approach for Masonry Materials
2015
Abstract A FE-Meshless multiscale computational strategy for the analysis of running bond masonry is presented. The Meshless Method (MM) is adopted to solve the boundary value problem (BVP) at the mesoscopic level. The representative unit cell is composed by the aggregate and the surrounding joints, the former assumed to behave elastically while the latter are simulated as non-associated elastic-plastic zero-thickness interfaces with a softening response. Macroscopic localization of plastic bands is obtained performing a spectral analysis of the tangent stiffness matrix. Localized plastic bands are embedded into the quadrature points area of the macroscopic finite elements.
Functional characterization of Tat protein from human immunodeficiency virus. Evidence that Tat links viral RNAs to nuclear matrix.
1990
The processes of transcription and posttranscription are assumed to proceed in close association with the nuclear matrix. In this study we demonstrated that Tat, the trans-activating protein from human immunodeficiency virus type 1 (HIV-1), binds both to the TAR region of the nascent HIV mRNAs and the nuclear matrix with high affinity. Both North/Western blotting experiments and nitrocellulose binding studies revealed that Tat binds with an association constant (K alpha) of approximately 1 x 10(9) M-1 to the TAR segment of HIV RNA; binding of Tat to this sequence which is present between position 32 and 82 downstream from the TATA box was also confirmed by gel retardation assays. Binding of…
Impact of graphitic carbon nitride nanosheets in mixed- matrix membranes for removal of heavy metals from water
2021
International audience; Removal of heavy metal ions from water is being a challenge and Polysulfone (PSf) membranes have shown great potential to remove them from contaminated solutions. In this work, the introduction of Graphitic carbon nitride nanosheets (g-C3N4) into PSf membranes was implemented to improve the permeability and separation performance of PSf membranes. g-C3N4 was incorporated into the membrane matrix via nonsolvent induced phase inversion method. The prepared mixed matrix membranes showed enhanced performances towards water filtration. The incorporation of g-C3N4 into the membrane matrix caused an increase in the desired physicochemical properties like hydrophilicity and …
Proenzyme Structure and Activation of Astacin Metallopeptidase
2010
Proteolysis is regulated by inactive (latent) zymogens, with a prosegment preventing access of substrates to the active-site cleft of the enzyme. How latency is maintained often depends on the catalytic mechanism of the protease. For example, in several families of the metzincin metallopeptidases, a >cysteine switch> mechanism involves a conserved prosegment motif with a cysteine residue that coordinates the catalytic zinc ion. Another family of metzincins, the astacins, do not possess a cysteine switch, so latency is maintained by other means. We have solved the high resolution crystal structure of proastacin from the European crayfish, Astacus astacus. Its prosegment is the shortest struc…
MT5-MMP regulates adult neural stem cell functional quiescence through the cleavage of N-cadherin.
2014
The identification of mechanisms that maintain stem cell niche architecture and homeostasis is fundamental to our understanding of tissue renewal and repair. Cell adhesion is a well-characterized mechanism for developmental morphogenetic processes, but its contribution to the dynamic regulation of adult mammalian stem cell niches is still poorly defined. We show that N-cadherin-mediated anchorage of neural stem cells (NSCs) to ependymocytes in the adult murine subependymal zone modulates their quiescence. We further identify MT5-MMP as a membrane-type metalloproteinase responsible for the shedding of the N-cadherin ectodomain in this niche. MT5-MMP is co-expressed with N-cadherin in adult N…
Type IV collagen and its degradation in paralyzed human muscle: Effect of functional electrical stimulation
2000
The purpose of this study was to evaluate the effects of spinal cord injury (SCI) and functional electrical stimulation (FES) of paralyzed muscles on type IV collagen content and proteins involving its degradation, which is initiated by matrix metalloproteinase (MMP)-2 and -9 and regulated by their tissue inhibitors (TIMPs)-2 and -1. Ten SCI subjects participated in an 18-month program of functional electrical stimulation (FES) of their leg muscles. Needle biopsies were taken from the vastus lateralis muscle before and at various times during the training period, and from able-bodied controls. Type IV collagen concentration was unaltered. ProMMP-2 level of SCI subjects before the training p…
Preparation of Polymer-Supported Polyazamacrocycles. The Role of the Polymeric Matrix in the Preparation of Polymer-Supported Polyazamacrocycles
2000
Different approaches have been studied for the preparation of resins containing different polyazamacrocycles. Preparation of monolithic resins by polymerization of vinylic derivatives of the corresponding macrocycles is shown to be a more versatile strategy for this purpose. The use of energy-dispersive analysis by X-ray has revealed to be a very useful tool for the rapid evaluation of the interaction of those materials with both anions and cations and has allowed the corresponding selectivity trends to be obtained in a fast and simple way. Important effects of the polymeric matrix are observed in some cases.
A New Nuclear Function of the Entamoeba histolytica Glycolytic Enzyme Enolase: The Metabolic Regulation of Cytosine-5 Methyltransferase 2 (Dnmt2) Act…
2009
Cytosine-5 methyltransferases of the Dnmt2 family function as DNA and tRNA methyltransferases. Insight into the role and biological significance of Dnmt2 is greatly hampered by a lack of knowledge about its protein interactions. In this report, we address the subject of protein interaction by identifying enolase through a yeast two-hybrid screen as a Dnmt2-binding protein. Enolase, which is known to catalyze the conversion of 2-phosphoglycerate (2-PG) to phosphoenolpyruvate (PEP), was shown to have both a cytoplasmatic and a nuclear localization in the parasite Entamoeba histolytica. We discovered that enolase acts as a Dnmt2 inhibitor. This unexpected inhibitory activity was antagonized by…