A practical approach to high performance capillary electrophoresis with biosynthetic human growth hormone as a model protein

Biosynthetic human Growth Hormone (B-hGH) is a protein comprising 191 amino acids. The molecular weight is 22,125 and the isoelectric point is close to pH 5. Due to the ready availability of closely related analogues B-hGH was used as a model protein thus allowing for the demonstration and evaluation of the high resolution capability of high performance capillary electrophoresis (HPCE). The same apparatus was used throughout the experiments and an optimum signal-to-noise ratio was found at 200 nm. Linearity was observed between peak area, retention time and the hGH concentration or sample introduction time. Baseline separation of hGH, desamido hGH and didesamido hGH was obtained. Examples showing analysis with 1 million theoretical plates per meter, high speed separation, simultaneous analysis of multiple samples, sample stacking, hGH tryptic digest, and hGH lysate are reported. The use of electrophoretic velocities instead of apparent velocities for peak identification is illustrated.     

(Z)-3-p-tolylsulfinylacrylonitrile as a chiral dienophile: diels-alder reactions with furan and acyclic dienes

The behavior of (Z)-3-p-tolylsulfinylacrylonitrile (1) as a chiral dienophile has been evaluated from its reactions with furan and acyclic dienes. Electrostatic interactions of the cyano group with the sulfinyl one restrict the conformational mobility around the C-S bond, thus controlling the pi-facial selectivity, which is almost complete in all cases, the approach of the diene from the less-hindered face of the dienophile (that bearing the lone electron pair) in the predominant rotamer being the favored one. The regioselectivity is also completely controlled by the cyano group. Additionally, the reactivity of compound 1 as well as its endo-selectivity are both higher than those observed for the corresponding (Z)-3-sulfinylacrylates, thus proving the potential of sulfinylnitriles as chiral dienophiles.     

Narrow band quantitative and multivariate electroencephalogram analysis of peri-adolescent period

ABSTRACT: BACKGROUND: The peri-adolescent period is a crucial developmental moment of transition from childhood to emergent adulthood. The present report analyses the differences in Power Spectrum (PS) of the Electroencephalogram (EEG) between late childhood (24 children between 8 and 13 years old) and young adulthood (24 young adults between 18 and 23 years old). RESULTS: The narrow band analysis of the Electroencephalogram was computed in the frequency range of 0--20 Hz. The analysis of mean and variance suggested that six frequency ranges presented a different rate of maturation at these ages, namely: low delta, delta-theta, low alpha, high alpha, low beta and high beta. For most of these bands the maturation seems to occur later in anterior sites than posterior sites. Correlational analysis showed a lower pattern of correlation between different frequencies in children than in young adults, suggesting a certain asynchrony in the maturation of different rhythms. The topographical analysis revealed similar topographies of the different rhythms in children and young adults. Principal Component Analysis (PCA) demonstrated the same internal structure for the Electroencephalogram of both age groups. Principal Component Analysis allowed to separate four subcomponents in the alpha range. All these subcomponents peaked at a lower frequency in children than in young adults. CONCLUSIONS: The present approaches complement and solve some of the incertitudes when the classical brain broad rhythm analysis is applied. Children have a higher absolute power than young adults for frequency ranges between 0-20 Hz, the correlation of Power Spectrum (PS) with age and the variance age comparison showed that there are six ranges of frequencies that can distinguish the level of EEG maturation in children and adults. The establishment of maturational order of different frequencies and its possible maturational interdependence would require a complete series including all the different ages.     

The Effect of α-, β- and γ-Cyclodextrin on Wheat Dough and Bread Properties

Cyclodextrins (CDs) are cyclic oligosaccharides that have found widespread application in numerous fields. CDs have revealed a number of various health benefits, making them potentially useful food supplements and nutraceuticals. In this study, the impact of α-, β-, and γ-CD at different concentrations (up to 8% of the flour weight) on the wheat dough and bread properties were investigated. The impact on dough properties was assessed by alveograph analysis, and it was found that especially β-CD affected the viscoelastic properties. This behavior correlates well with a direct interaction of the CDs with the proteins of the gluten network. The impact on bread volume and bread staling was also assessed. The bread volume was in general not significantly affected by the addition of up to 4% CD, except for 4% α-CD, which slightly increased the bread volume. Larger concentrations of CDs lead to decreasing bread volumes. Bread staling was investigated by texture analysis and low field nuclear magnetic resonance spectroscopy (LF-NMR) measurements, and no effect of the addition of CDs on the staling was observed. Up to 4% CD can, therefore, be added to wheat bread with only minor effects on the dough and bread properties.     

Thermochemistry of the reaction catalyzed by malate dehydrogenase

The heat of reason for the process

has been determined to be ?21.4±0.2 kcal mol^?1. The similar reactions catalyzed by lactate dehydrogenase (IUB No. 1.1.1.27) and alcohol dehydrogenase (IUB No. 1.1.1.1) are compared with reference to their Gibbs-Helmholtz thermodynamic parameters.     

Intravenous administration of Gd-DTPA prior to DWI does not affect the apparent diffusion constant

MRI measurements of water diffusion and blood perfusion are increasingly used for the evaluation of organ functionality and tissue viability (e.g., in tumors). While diffusion-weighted imaging is performed without contrast agents, measurement of blood perfusion is normally performed based on the administration of paramagnetic substances such as gadolinium diethylenetriamine pentaacetic acid (Gd-DTPA). Simultaneous measurements of these two parameters are often preferred. However, it may be argued that Gd-DTPA causes constriction of small blood vessels or alters hemodynamic parameters such as blood viscosity, thereby corrupting subsequent measurements of the apparent diffusion constant (ADC). The objective of the current study was to investigate the possible changes in the ADC in tumors following intravenous administration of 0.2 and 0.4 mmol/kg of Gd-DTPA in mice. The study was conducted with C3H mouse mammary carcinomas inoculated in the right foot of the animal subjects. The results were compared with findings in a sham group, demonstrating that Gd-DTPA had no significant impact on the ADC as measured in a 7-T animal system.     

Scanning electron microscopy of foreleg tarsal sense organs of the poultry red mite, Dermanyssus gallinae (DeGeer) (Acari:Dermanyssidae)

Scanning electron microscopy (SEM) studies on the poultry red mite, Dermanyssus gallinae (DeGeer), showed that the tip of the foreleg tarsus of both sexes and early instar stages (larvae, protonymph and deutonymph) bears a cluster of 10 blunt peg-type sensillae. Diversity in size, shape and surface features of the wall of these sensillae characterize the sensilla complex (sensory field). Two short setae (1 and 2) with smooth walls lack detectable pores, whereas three medium-sized setae (4, 5 and 8) bear pores in the wall. Four medium or long setae (3, 6, 7 and 9) have longitudinal grooves or ribs in the wall, whilst one seta (10) possesses both pores and grooves in the wall. Based on the morphology, it is suggested that the porous setae could be olfactory receptors, and the grooved setae could be mechanoreceptors.     

Scars of the Wigner Function

We propose a picture of Wigner function scars as a sequence of concentric rings along a two-dimensional surface inside a periodic orbit. This is verified for a two-dimensional plane that contains a classical hyperbolic orbit of a Hamiltonian system with 2 degrees of freedom. The stationary wave functions are the familiar mixture of scarred and random waves, but the spectral average of the Wigner functions in part of the plane is nearly that of a harmonic oscillator and individual states are also remarkably regular. These results are interpreted in terms of the semiclassical picture of chords and centers.