Chitinase and beta-N-acetylglycosaminidase in the digestive juice of Helix pomatia.

A beta-N-acetylglucosaminidase from Helix pomatia digestive juice was separated and partly purified by gel chromatography. The optimal pH for the degradation of p-nitrophenyl-N-acetyl-beta-D-glucosaminide was 3.4. The molecular weight was around 160 000 and the pI = 4.95. In the same gel chromatography run two chitinase active peaks were also obtained. These chitinase active peaks were also obtained. These chitinases, with molecular weights around 26 000 and 13 000, had somewhat different pH activity curves with optima at 4.2 and 4.3. By isoelectric focusing the first peak with molecular weight around 26 000 was divided in two chitinase active regions with pI at 5.7 and 3.5. The second peak with molecular weight around 13 000 had a pI at 7.3.     

Comparison of protein adsorption patterns onto differently charged hydrophilic superparamagnetic iron oxide particles obtained in vitro and ex vivo.

Protein adsorption patterns of superparamagnetic iron oxides (SPIO) were evaluated by two-dimensional electrophoresis (2-DE) after in vitro incubation of the particles in plasma or serum. SPIO particles having positive (MKK 1211), negative (MKA 1211), or neutral (MKG 1411) charge were used. Protein adsorption patterns of different charged SPIO particles acquired in vitro and recollected 5 min after intravenous injection into rats (ex vivo) were compared. For the uncharged MKG 1411 particles, the differences of protein adsorption patterns were negligible and only minor differences were found for the negatively charged MKA 1211 and positively charged MKK 1211 particles. A good correlation between in vitro and ex vivo data could be shown. For the evaluation of protein adsorption patterns of SPIO particles determining organ distribution and allowing estimation of site-specific delivery (drug targeting), the currently used protocol for 2-DE analysis could be confirmed.     

Isothermal Photo Differential Scanning Calorimetry. Crosslinking polymerization of multifunctional monomers in presence of visible light photoinitiators

The effect of photoinitating (camphorquinone/amines) system concentration and sample thickness on the photopolymerization of triethyleneglycol dimethacrylate/2-hydroxypropyl methacrylate has been investigated. The rate of photopolymerization reaches a maximum and then decreases as the concentration of photoinitiating system increases. This effect has been intepreted as inner filter effect. This revised version was published online in July 2006 with corrections to the Cover Date.     

On the moment of inertia in deformed Ba-Xe nuclei as deduced from gamma-gamma energy correlation experiments

The γ-rays following reactions induced by bombarding targets of ^{114, 116, 118, 120, 122}Sn with 118 MeV ¹²C ions were investigated using six NaI(Tl) detectors in a two-dimensional coincidence arrangement. Experimental energy-correlation spectra were extracted from the original coincidence matrices. The energy-correlation spectra exhibit the features expected for rotational nuclei and were used to deduce information on the moment of inertia $\text{I}{}^{\mathrm{(2)}}\text{= ΔI/Δω}$. The gross properties of the behaviour of $\text{I}$⁽²⁾ in the Ba-Xe region are discussed together with their interpretation within the cranked shell model (CSM).     

Demethylation of methylmercury during inorganic mercury determination by the magos cold vapor atomic absorption technique

Previous animal experiments suggested that the Magos cold vapor atomic absorption spectroscopic (CVAAS) method might overestimate the concentrations of inorganic mercury (I-Hg) in the presence of methylmercury (MeHg). In the present study it is shown that this error is due to a fast degradation of MeHg during the formation of the analytical signal. For brain samples, about 5% of the total amount of MeHg in the reaction vessel is degraded to I-Hg. Speciation of Hg in aqueous solution of MeHg chloride, after purification with ionexchange chromatography using the Magos method, showed that about 9% was I-Hg. Analysis by NMR of MeHg chloride and MeHg hydroxide showed that less than 1% was in the form of I-Hg. The absolute magnitude of the error in the CVAAS method is dependent on the amounts of SnCl₂ and MeHg in the reaction vessel; however, the ratio of I-Hg to total (T-Hg) is shown to be independent of the amount of MeHg (25.5–255 ng as Hg) in the reaction vessel. A procedure for corrections is proposed, based on the results from these studies and empirical data from speciation analyses of brain tissue from MeHg-exposed rats and rabbits.     

Interaction between gravity and moving superconductors

We propose a unified phenomenological theory to investigate the interaction between arbitrarily moving superconductors and gravitational fields including the Newtonian gravity, gravitational waves, vector transverse gravitoelectric fields, and vector gravitomagnetic fields. In the limit of weak field and low velocity, the expressions for the induced electromagnetic and gravitational fields in the interior of a moving superconductor are obtained. The Meissner effect, London moment, DeWitt effect, effects of gravitational wave on a superconductor, and induced electric fields in the interior of a freely vibrating superconductor are recovered from these two expressions. We demonstrate that the weak equivalence principle is valid in superconductivity, that Newtonian gravity and gravitational waves will penetrate either a moving superconductor or a superconductor at rest, and that a superconductor at rest cannot shield either vector gravitomagnetic fields or vector transverse gravitoelectric fields.     

Angular correlation study of levels in 16C

Angular correlation measurements using the ¹⁴C(t, pγ)¹⁶C reaction result in the following spin assignments to levels in ¹⁶C: E_x = 1.766 MeV, J = 2; E_x = 3.980 MeV, J = 2; E_x = 4.083 MeV, J = 3; E_x = 4.138 MeV, J = 4.     

Quantitative study of EγEγ correlations in the 122Sn + 106 MeV 12C compound system

The E_γE_γ correlations in the ¹²²Sn + 106 MeV ¹²C compound system have been measured by using the techniques of time of flight to reject events due to neutrons and of unfolding to remove events due to Compton escape. The rotational correlations in the measured matrix can be followed up to E_γ = 1.2 MeV which is shown to correspond to a collective spin of 15. An attempt to estimate the amount of aligned angular momentum by utilizing the intensities in the unfolded matrix failed mainly because at least half of all E2 γ-rays showed no rotational correlations. An independent evidence for this background of uncorrelated events is obtained by comparing the rotational correlations in the data with the rotational correlations obtained by simulating the decay of the known discrete levels in ^{127, 128}Ba on a computer. The comparison indicates that the observed rotational correlations are mainly due to the known discrete transitions. While the moment of inertia obtained from the correlation pattern is less than 80 % of the rigid-body value the high-energy end of the spectrum of E2 radiation can only be explained if γ-ray energy and spin are related by the rigid-body moment of inertia. The area of positive correlations that occurs in most published correlation plots at E₁ = E₂ and at the high-energy end of the E2 radiation is understood from the unfolding to be an artifact of the subtraction procedure.     

Quantitative information from x-ray diffraction of nylon-6 yarns. I. Development of a model for the analytical description of equatorial x-ray profiles

A wide-angle x-ray method has been developed by which quantitative structural information can be obtained on nylon-6 yarns. To this end, experimental equatorial diffractometer scans measured in transmission were fitted to a mathematical model describing the profiles as the envelopes of three bell-shaped functions. Four different models were investigated using, respectively, Gauss, Lorentz (Cauchy), Logistic, and Pearson-VII functions. The last model, which can be regarded as a generalized Lorentz function, gave the best fit. On the basis of a statistical analysis of the results of well-separated x-ray peaks, two parameters could be fixed. Another reduction of the number of parameters was achieved by interrelating the peak areas of the two outer reflections. These reductions widened the applicability of a computer program based on the aforementioned model to highly overlapping x-ray peaks. So the whole variety of x-ray scans, which can be obtained from nylon-6 yarns made under widely varying process conditions, can be well described. The fitting procedures provide unique solutions and hence objectively determined parameters.