Search results for "Molecular mass"

Morphology and thermal properties of foams prepared via thermally induced phase separation based on polylactic acid blends

2012

Blends of poly-l-lactic acid with two different types of polylactic acid with different average molecular weights (50,000 and 175,000 g/mol, respectively) in different proportions (90/10, 80/20 and 70/30) were utilized in order to produce biodegradable and biocompatible scaffolds for soft tissue engineering applications. The scaffolds were produced via thermally induced phase separation starting from ternary systems where dioxane was the solvent and water the non-solvent. Morphology (average pore size and interconnection) was evaluated by scanning electron microscopy. Foams apparent density was also evaluated (porosity ranges from 87% to 92%). Moreover, a differential scanning calorimetry …

Inverse Spin Fractionation:  a Tool to Fractionate Sodium Hyaluronate

2006

Synthesis and characterization of novel bile-acid – heteroaryl conjugates with N-(2-aminoethyl)amido linker

2008

Abstract Four novel bile acid conjugates N-[2-([2,2′]-bithiophen-5-ylmethyl)aminoethyl]-3α-hydroxy-5β-cholan-24-amide (1), N-[2-([2,2′]-bithiophen-5-ylmethyl)aminoethyl]-3α,7α,12α-trihydroxy-5β-cholan-24-amide (2), N-[2-(1H-pyrrol-2-ylmethyl)aminoethyl]-3α-hydroxy-5β-cholan-24-amide (3), N-[2-(pyridin-2-ylmethyl)aminoethyl]-3α-hydroxy-5β-cholan-24-amide (4) have been synthesized in moderate to good yields, and their structures have been characterized by 1H, 13C, 13C DEPT-135, PFG 1H,13C HMQC, and PFG 1H,13C HMBC NMR spectra. Their molecular weights and elemental compositions have been determined by ESI-TOF mass spectrometry and elemental analyses. Crystal structure of 1 characterized with o…

Molgewichtsbestimmungen an polyacrolein-thiophenolmercaptalen. Polymere acroleine, 13. Mitteilung

1959

Es wird die Herstelung einiger Polyacrolein-Mercaptale beschrieben. Die Thiophenol mercaptable lassen sich in Fraktionen zerlegen. Die Fraktionierung erfolgt nach dem Molgewicht und nicht nach dem Umsetzungsgrad. Osmotische Messungen ergeben in verschiedenen Losungsmitteln ubereinstimmende Polymerisationsgrade. Es wird eine Viskositats- Molgewichts-Beziehung angegeben, und fur 2 verschiedene Polyacrolein-Thiophenolmercaptale werden die Massenverteilungsfunktionen bestimmt. The preparation of some polyacroleinimercaptals is described. It is possible to fractionate the thiophenolmercaptals. The fractionation goes according to the molecular weight and not according to the degree of conversion.…

Complete Sequence of the 24-mer Hemocyanin of the TarantulaEurypelma californicum

2000

Hemocyanins are large oligomeric respiratory proteins found in many arthropods and molluscs. The hemocyanin of the tarantula Eurypelma californicum is a 24-mer protein complex with molecular mass of 1,726,459 Da that consists of seven different polypeptides (a–g), each occupying a distinct position within the native molecule. Here we report the complete molecular structure of the E. californicumhemocyanin as deduced from the corresponding cDNAs. This represents the first complex arthropod hemocyanin to be completely sequenced. The different subunits display 52–66% amino acid sequence identity. Within the subunits, the central domain, which bears the active center with the copper-binding sit…

Polypeptide composition of invertase-containing vesicles of Saccharomyces cerevisiae

1990

Vesicles containing invertase activity were obtained from protoplast homogenates of Saccharomyces cerevisiae by differential centrifugation followed by gel chromatography. These vesicles were similar in size and shape to yeast coated vesicles, and appear to have a complex polypeptide composition. Most of these polypeptides were seemingly bound to the surface of the vesicular structures, being released by treatment with alkali. A protein with an electrophoretic mobility similar to that of yeast clathrin (molecular mass of 185 kDa) co-purified with vesicles containing invertase activity, and exhibited cross-reactivity with anti-mammalian (pig) clathrin antibodies.

Simultaneous Anodic Dissolution and Passivation of Nickel in Moderate Acid Medium

2006

The EQCM results show that nickel electrodissolution and nickel passivation occur simultaneously in a sulphate acid media of pH = 3.5. Mass balances have been done from the instantaneous F(dm/dQ) function. The fitting of the experimental i = f(E) and -dm/dt = g(E) curves to the theoretical equations allow to obtain information about the kinetic parameters and the molecular mass of the species involved in the electrochemical processes.

Automated multi-dimensional liquid chromatography

2004

A comprehensive on-line sample clean-up with an integrated two-dimensional HPLC system was developed for the analysis of natural peptides. Samples comprised of endogenous peptides with molecular weights up to 20 kDa were generated from human hemofiltrate (HF) obtained from patients with chronic renal failure. The (poly-)peptides were separated using novel silica-based restricted access materials with strong cation-exchange functionalities (SCX-RAM). The size-selective sample fractionation step is followed by cation-exchange chromatography as the first dimension. The subsequent second dimension of separation is based on hydrophobic interaction using four parallel short reversed-phase (RP) co…

Primary structure and unusual carbohydrate moiety of functional unit 2-c of keyhole limpet hemocyanin (KLH)

1999

Abstract The complete amino acid sequence of the Megathura crenulata hemocyanin functional unit KLH2-c was determined by direct sequencing and matrix-assisted laser desorption ionization mass spectrometry of the protein, and of peptides obtained by cleavage with EndoLysC proteinase, chymotrypsin and cyanogen bromide. This is the first complete primary structure of a functional unit c from a gastropod hemocyanin. KLH2-c consists of 420 amino acid residues. Circular dichroism spectra indicated approx. 31% β-sheet and 29% α-helix contents. A multiple sequence alignment with other molluscan hemocyanin functional units revealed average identities between 41 and 49%, but 55% in case of Octopus he…

The Pandinus imperator haemolymph lipoprotein, an unusual phosphatidylserine carrying lipoprotein.

2009

The haemolymph lipoprotein of the scorpion, Pandinus imperator was isolated and characterised. Contrary to the lipoproteins of insects and the discoidal HDL-lipoproteins of a crayfish and polychaete, the Pandinus lipoprotein consists of three instead of two apoproteins (apoPiLp I = 230 kDa, apoPiLp II = 130 kDa and apoPiLp III = 120 kDa). The apolipoproteins are arranged in varying stoichiometries as judged by cross-linking experiments. In lipoprotein samples from individual animals, the two smaller subunits occurred in a 1:1 stoichiometry, while the relative amount of the 230 kDa peptide varied. The lipoprotein is a slightly heart-shaped HDL with a diameter of approximately 15 nm. It is pr…