Search results for " Gradient"
showing 10 items of 575 documents
PLLA-BASED SCAFFOLDS FOR OSTEOCHONDRAL TISSUE REGENERATION VIA THERMALLY INDUCED PHASE SEPARATION TECHNIQUE
L’ingegneria tessutale (TE) è una scienza multidisciplinare che mira a progettare e sviluppare sostituti biologici per migliorare, riparare e/o sostituire i tessuti negli organismi umani. Sulla base della tipica triade dell’ingegneria tessutale è incentrato il primo capitolo Scaffold, Source and Signal; lo scaffold funge da struttura tridimensionale, le cellule rappresentano la source mentre il bioreattore fornisce gli adeguati segnali chimico/fisici. In questo lavoro di tesi sono stati presi in considerazione tutti e tre questi aspetti avendo come obiettivo la rigenerazione osteocondrale. La guarigione dei difetti osteocondrali, riguardanti le lesioni della cartilagine che si esten- dono f…
Impact Assessment of Skidding Extraction: Effects on Physical and Chemical Properties of Forest Soils and on Maple Seedling Growing along the Skid Tr…
2019
Several studies investigated soil disturbances caused on skid trails by forest logging. However, there is still a lack of knowledge about the severity and the distance of disturbances along both sides from the trails. The aims of this study were: i) to investigate the changes in physical and chemical properties of soil along the sides of skidding trails
Influence of M23C6 carbides on the heterogeneous strain development in annealed 420 stainless steel
2020
Understanding the local strain enhancement and lattice distortion resulting from different microstructure features in metal alloys is crucial in many engineering processes. The development of heterogeneous strain not only plays an important role in the work hardening of the material but also in other processes such as recrystallization and damage inheritance and fracture. Isolating the contribution of precipitates to the development of heterogeneous strain can be challenging due to the presence of grain boundaries or other microstructure features that might cause ambiguous interpretation. In this work a statistical analysis of local strains measured by electron back scatter diffraction and …
Type V collagen-induced upregulation of capn2 (large subunit of m-calpain) gene expression and DNA fragmentation in 8701-BC breast cancer cells
2011
Abstract Type V collagen is known to be over-deposited in the stroma of ductal infiltrating carcinomas of the breast. When used as a substrate, type V collagen restrains growth and invasion, and affects gene expression of 8701-BC ductal infiltrating carcinomas cells. Here we supplement existing data by demonstrating type V collagen dependent upregulation of capn2 gene expression in 8701-BC cells through differential display-PCR and Western blot assays. Furthermore, we suggest that our data obtained by centrifugal sedimentation and electrophoresis strongly suggest a correlation between calpain overproduction and DNA fragmentation, since the incubation with calpain inhibitor partly reverts th…
A homemade device for linear sucrose gradients
2008
We have developed a simple and inexpensive device to obtain linear sucrose gradients with commonly used laboratory materials--a syringe, a flask, a plastic tube, and a piece of Pongo (Play-Doh). Refractive index values measured on sucrose fractions collected using our system demonstrate both the linearity and reliability of the gradients obtained.
Precipitation chromatography. III. Optimization of the experimental conditions and determination of the polydispersity of fractions
1974
The influence of the solvent–nonsolvent gradient and the temperature gradient on the efficiency of the precipitation chromatography is investigated with radically and anionically prepared polystyrene samples. Only a combination of both gradients gives optimal effectiveness of the column. The separating power of the column was determined by using mixtures of well defined samples. From the elution curves of the mixtures the nonuniformity Ufr of fractions can be estimated. For fractions of anionically prepared polystyrenes Ufr is on the average 0.001; this value is of the same order of magnitude as the statistical error. These results show that with this chromatographic method it is possible t…
Purification and characterization of leucine aminopeptidase from kidney bean cotyledons
1992
A leucine aminopeptidase (EC 3,4,11.1) was purified from cotyledons of resting kidney beans (Phaseolus vulgaris L. cv. Processor) by acidic extraction, ammonium sulfate fractionation and chromatography on DEAE-Sephacel, Sephacryl S-300, Mono Q HPLC and Superose HPLC columns. The yield of the 317-fold purified enzyme was 9%. On gel filtrations on Sephacryl S-300 and Superose HPLC the elution volumes of the enzyme corresponded to an M, of 360 000. The enzyme gave one band on native gel electrophoresis and an electrophoretic titration in an immobilized pH gradient gave a single curve with a pI of 4.8. Two bands were observed in an SDS-gel electrophoresis with Mr values of 58 000 and 60 000 bot…
Structure and function of ferredoxin-NADP+-oxidoreductase
1987
The redox-enzyme ferredoxin-NADP-oxidoreductase has been shown to be activated by light and inactivated in the dark. This review will summarize recent data concerning the biochemical characterization of the enzyme compared to its in-vivo activation. Further-more the mechanism of this activation process is discussed as a conformational change caused by the light-driven proton gradient.
Assays of Proteasome-Dependent Cleavage Products
2005
The degradation of misfolded, aged, or no longer needed cytosolic proteins depends largely on the ubiquitin-proteasome system. Proteasomes degrade their substrates into fragments of 3-20 amino acids. Human 20S proteasomes can be purified from human erythrocytes by batch adsorption to DEAE-cellulose, ammonium sulfate precipitation, anion-exchange fast protein liquid chromatography (FPLC), and glycerol density gradient ultracentrifugation. 20S proteasomes purified by this method are suitable for the in vitro digestion of synthetic peptides as well as full-length proteins. The degradation products produced by proteasomes are separated by reversed-phase HPLC using an acetonitrile gradient. The …
1990
The determination of average molecular weights and the characterization of molecular weight distributions by the ratio of the weight- to number-average molecular weights Mw/Mn from sedimentation equilibrium in the ultracentrifuge are described. The essential measurement of the density profile of the mixed solvent is conducted according to Munk (Macromolecules15, 500 (1982)). Special evaluation of the polymer band in the equilibrium allowed to deduce from the observed concentration profile Mw and Mn of a series of poly(methyl methacrylate) samples and thus to characterize the molecular weight distribution of the samples.