Thermal stability

To achieve the aim, the first objective is preliminary experiments on preparation of polypropylene blends with silicone elastomer masterbatch and characterize by analysis of mass composition, mechanical properties, and dynamic mechanical properties to investigate any improvement of properties. The silicone elastomer masterbatch will then be substituted with propylene-maleic anhydride graft copolymer waxes or other compatibilizers.

147p runthenight05 01-03-2023 7 3   Download

The objectives of this research work are: Study the clay intercalation by organic dye and develop a process to produce nanoclay-dye pigment with better stability and good performance; Conduct structural characterization to verify the level of intercalation and stability of clay-dye pigment by using X-Ray diffraction (XRD) and Transmission Electron Microscopy (TEM); Investigate the thermal stability of clay dye pigment using Thermo Gravimetric Analysis (TGA) to reveal the effect of dye intercalation into the clay on improving thermal stability of organic dye; Compound the clay- pigment with ...

141p runthenight07 01-03-2023 5 3   Download

In this Masters thesis computational modelling techniques were employed to investigate iron-free apo-Lactoferrin (apo-Lf) structural conformation changes in the presence of variant temperature and pH. These conditions represent the environment most milk protein goes through in food processing and the production of food products.

162p runthenight04 02-02-2023 8 3   Download

Manufacture composite based on epoxy reinforced by glass fiber with organ – modified nanosilica using organotitanate curing agent that have good mechanical strength, thermal stability, flame restraint ability; improve the toughness of epoxy resin by incorporating reinforcing agent such as organ – modified nanosilica and glass fiber with appropriate manufacturing condition and ratio.

28p capheviahe26 25-01-2021 31 3   Download

Polypropylene/ maleic anhydride /organic montmorillonite nanocomposites (PP/ MA/ Org-MMT) have been prepared via direct melt intercalation in an internal mixer. Maleic anhydride (MA) was used as a compatibilizer to improve the dispersability of the clay. The structures of nanocomposites have been characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and scanning electron microscopy (SEM). Mechanical properties and thermal stability were determined by tensile analysis and thermogravimetric analysis (TGA), respectively.

8p 12120609 01-06-2020 22 2   Download

The catalyst 7.5% NiO/TiO2 and seven samples of NiO/γ-Al2O3 with NiO content from 7.5% to 60% have been obtained and studied. Physico-chemical characteristics of the catalysts were determined by methods of Adsorption (BET), X-ray Diffraction (XRD), TemperatureProgrammed Reduction (TPR) and Hydrogen Pulse Titration. The catalytic properties of the obtained samples were investigated in the reaction of CO methanation at temperatures 180 – 220◦C and mole ratios hydrogen/carbon monoxide 25-100.

16p 12120609 01-06-2020 7 1   Download

(BQ) In the study, temperature measurements have been made for Ti–6Al–4V workpieces with various duty factors to clarify the essential causes of difficulty in machining titanium alloys and observe the optimal duty factor in terms of productivity and quality.

7p xuanphuongdhts 27-03-2017 49 4   Download

Arecombinant streptococcalC5apeptidasewas expressed in Escherichia coliand its catalytic properties and thermal sta-bility were subjected to examination. It was shown that the NH2 -terminal region ofC5a peptidase (Asn32–Asp79/ Lys90) forms the pro-sequence segment. Upon maturation the propeptide is hydrolyzed either via an autocatalytic intramolecular cleavage or by exogenous protease strepto-pain. At pH 7.4 the enzyme exhibited maximum activity in the narrow range oftemperatures between 40 and 43
C....

13p research12 29-04-2013 48 3   Download

The thermal stabilityofperoxidase fromleavesof theAfrican oil palm treeElaeis guineensis(AOPTP) at pH 3.0 was studied by differential scanning calorimetry (DSC), intrinsic fluorescence, CD and enzymatic assays.The spectral parameters asmonitoredby ellipticity changes in the far-UV CD spectrum of the enzyme as well as the increase in tryp-tophan intensity emission upon heating, together with changes in enzymatic activity with temperature were seen to be good complements to the highly sensitive but integral methodofDSC....

7p research12 29-04-2013 45 3   Download

The proposed biological function ofb-lactoglobulins as transporting proteins assumes a binding ability for ligands andhighstabilityunder theacidic conditionsof the stomach. This work shows that the conformational stability of non-ruminant porcine b-lactoglobulin (BLG) is not consistent with this hypothesis. Thermal denaturation of porcine BLG was studied by high-sensitivity differential scanning calori-metry within the pH range 2.0–10.0.

11p research12 23-04-2013 44 5   Download

The crystal structures of thermophilic xylanases from Chaetomium thermophilumandNonomuraea flexuosawere determined at 1.75 and 2.1 A˚ resolution, respectively. Both enzymes have the overall fold typical to family 11 xylanases with two highly twistedb-sheets forminga large cleft. The comparison of 12 crystal structures of family 11 xylanases from both mesophilic and thermophilic organisms showed that the structures of different xylanases arevery similar.

14p tumor12 20-04-2013 37 3   Download

The major cellulase secreted by the filamentous fungus Trichoderma reeseiis cellobiohydrolase Cel7A. Its three-dimensional structure has been solved and various mutant enzymes produced. In order to study the potential use of T. reeseiCel7A in the alkaline pHrange, the thermal sta-bilityofCel7Awas studiedas a functionof pHwith thewild-type and two mutant enzymes using different spectroscopic methods. Tryptophan fluorescence and CD measurements of the wild-type enzyme show an optimal thermostability between pH3.5–5.

8p tumor12 20-04-2013 40 4   Download

We purified pancreatic deoxyribonucleases I (DNases I) from three snakes, Elaphe quadrivirgata, Elaphe climaco-phoraandAgkistrodon blomhoffii, and cloned their cDNAs. Each mature snake DNase I protein comprised 262 amino acids. Wild-type snake DNases I with Leu130 were more thermally unstable than wild-type mammalian and avian DNases I with Ile130. After substitution of Leu130Ile, the thermal stabilities of the snake enzymes were higher than those of their wild-type counterparts and similar to mam-malian wild-type enzyme levels....

8p tumor12 20-04-2013 41 3   Download

To probe the stability of the seven-iron ferredoxin from Thermus thermophilus(FdTt), we investigated its chemical and thermal denaturationprocesses insolution.Aspredicted from the crystal structure, FdTt is extremely resistant to perturbation. The guanidine hydrochloride-induced unfolding transition shows a midpoint at 6.5M(pH 7, 20
C), andthe thermalmidpoint is aboveboiling, at 114
C. The stability of FdTt is much lower at acidic pH, suggesting that electrostatic interactions are important for the high stability at higher pH.

8p fptmusic 12-04-2013 59 5   Download

Heteronuclear NMR relaxation measurements and hydro-gen exchange data have been used to characterize protein dynamics in the presence or absence of stabilizing solutes from hyperthermophiles. Rubredoxin from Desulfovibrio gigaswas selected as a model protein and the effect of diglycerol phosphate on its dynamic behaviour was studied. The presence of 100 mMdiglycerol phosphate induces a fourfold increase in the half-life for thermal denaturation ofD.

9p fptmusic 12-04-2013 38 3   Download

Neuroglobin (Ngb) and cytoglobin (Cygb), recent additions to the globin family, display a hexa-coordinated (bis-histidyl) heme in the absence of external ligands. Although these proteins have the classical globin fold they reveal a very high thermal stability with a melting temperature (Tm)of 100
C for Ngb and 95
C for Cygb. Moreover, flash photolysis experi-ments at high temperatures reveal that Ngb remains functional at 90
C

9p awards 06-04-2013 32 3   Download

The extreme thermal stabilization achieved by the introduction of a disul-fide bond (G8C⁄N60C) into the cysteine-free wild-type-like mutant (pWT) of the neutral protease fromBacillus stearothermophilus[Mansfeld J, Vri-end G, Dijkstra BW, Veltman OR, Van den Burg B, Venema G, Ulbrich-Hofmann R & Eijsink VG (1997)J Biol Chem 272, 11152–11156] was attributed to the fixation of the loop region 56–69.

12p awards 06-04-2013 43 3   Download

Thermodynamic parameters describing the conformational stability of the histidine-containing phosphocarrier protein fromStreptomyces coelicolor, scHPr, have been determined by steady-state fluorescence measurements of isothermal urea-denaturations, differential scanning calorimetry at different guanidinium hydrochloride concentrations and, independently, by far-UV circular dichroism measurements of isothermal urea-denaturations, and thermal denatura-tions at fixed urea concentrations.

17p dell39 03-04-2013 38 5   Download

HIV gp41(24–157) unfolds cooperatively over the pH range of 1.0–4.0 withTmvalues of 100
C. At pH 2.8, protein unfolding was 80% reversible and theDHvH /DHcal ratio of 3.7 is indicative of gp41 being trimeric. No evidence for a monomer–trimer equilibrium in the concentration range of 0.3–36lMwas obtained by DSC and tryptophan fluores-cence. Glycosylation of gp41 was found to have only a marginal impact on the thermal stability. Reduction of the disulfide bond or mutation of both cysteine residues had only a marginal impact on protein stability. ...

14p dell39 03-04-2013 45 3   Download

We have studied the stability of the histone-like, DNA-binding protein HU from the hyperthermophilic eubacteriumThermotoga maritimaand its E34D mutant by differential scanningmicrocalorimetry and CDunder acidic conditions at various concentrations within the range of 2–225lMof monomer. The thermal unfolding of both proteins is highly reversible and clearly follows a two-state dissociation/unfolding model from the folded, dimeric state to the unfolded, monomericone.

11p dell39 03-04-2013 47 4   Download