146 research outputs found
High Pressure Phase Behavior of Two Imidazolium-Based Ionic Liquids, [bmim][BF4] and [bmim][PF6]
Ionic Liquid-Induced Unique Structural Transitions of Proteins
The structural transitions of proteins in aqueous solutions of various ionic liquids (ILs) over a wide concentration range (x (mol% IL) = 0–30) were investigated using Fourier-transform infrared and near-UV circular dichroism spectroscopy combined with small-angle X-ray scattering. The proteins in the aqueous IL solutions showed two structural transition patterns: (i) the folded state → unfolded state → partial globular state (α-helical formation disrupted tertiary structure) and (ii) the folded state → unfolded state → aggregation (amyloid-like aggregation or disordered aggregation). We found that the helical formation of proteins in the condensed IL solutions was strongly related to the competition between the low polarity and denaturation effect of ions. Moreover, the amyloid-like aggregate formation correlated with the competition between the size of the confined water assemblies in the IL layer and the IL-amino acid residue interactions. On the basis of these results, we discussed the future applications of ILs, including their use as cryoprotectants for proteins and as agents for the suppression of amyloid formation
A new mass spectrograph
AbstractThe optical designs of two new types of mass spectrographs were studied. The first is a system that possesses a specially shaped magnet output boundary to satisfy the double-focusing condition for a wide mass range. The focal plane is usually curved. The second system is one in which a parallel ion beam is generated before the magnet, forming a straight double-focusing line. By introducing a quadrupole lens doublet such that the ion beam may be deflected in the same direction through the electric and magnetic fields, the overall image magnification can be arbitrarily controlled and stigmatic focusing achieved for the median ray
Non-Empirical Calculation of the π-Electronic States of Vinyl Chloride Molecule by Valence Bond Method
Effect of rehabilitation in patients undergoing hematopoietic stem cell transplantation
Patients undergoing hematopoietic stem cell transplantation (HSCT) tend to experience decline in physical function, mental function, and quality of life (QOL) after HSCT due to low activity caused by adverse reactions to chemotherapy used in pre-transplantation treatment and post-transplant complications. Rehabilitation for HSCT patients is effective in preventing decline in physical function, reducing fatigue, and improving QOL. A combination of aerobic exercise and strength training is recommended for exercise therapy. Risk management is also important in the implementation of exercise therapy, and the exercise intensity should be determined according to the presence of anemia, low platelet counts, or post-transplant complications. On the other hand, post-transplant complications can decrease the patient's motivation and daily activity level. A multidisciplinary approach, which includes physicians and nurses, is important to achieve early discharge from the hospital and as quick a return to society as possible
Detection of glycosylation and iron-binding protein modifications using Raman spectroscopy
In this study we demonstrate the use of Raman spectroscopy to determine protein modifications as a result of glycosylation and iron binding. Most proteins undergo some modifications after translation which can directly affect protein function. Identifying these modifications is particularly important in the production of biotherapeutic agents as they can affect stability, immunogenicity and pharmacokinetics. However, post-translational modifications can often be difficult to detect with regard to the subtle structural changes they induce in proteins. From their Raman spectra apo-and holo- forms of iron-binding proteins, transferrin and ferritin, could be readily distinguished and variations in spectral features as a result of structural changes could also be determined. In particular, differences in solvent exposure of aromatic amino acids residues could be identified between the open and closed forms of the iron-binding proteins. Protein modifications as a result of glycosylation can be even more difficult to identify. Through the application of the chemometric techniques of principal component analysis and partial least squares regression variations in Raman spectral features as a result of glycosylation induced structural modifications could be identified. These were then used to distinguish between glycosylated and non-glycosylated transferrin and to measure the relative concentrations of the glycoprotein within a mixture of the native non-glycosylated protein
Reaction of naphthalene-2,3-dicarboxaldehyde with enkephalins for LC-fluorescence and lc-ms analysis: Conformational studies by molecular modeling and H/D Exchange mass spectrometry
Non-Empirical Calculation of the π-Electronic States of Cyclo-Bntadiene Molecule by Valence Bond Method
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