DNA vaccine containing the mycobacterial hsp65 gene prevented insulitis in MLD-STZ diabetes

Background  

Our group previously demonstrated that a DNA plasmid encoding the mycobacterial 65-kDa heat shock protein (DNA-HSP65) displayed prophylactic and therapeutic effect in a mice model for tuberculosis. This protection was attributed to induction of a strong cellular immunity against HSP65. As specific immunity to HSP60 family has been detected in arthritis, multiple sclerosis and diabetes, the vaccination procedure with DNA-HSP65 could induce a cross-reactive immune response that could trigger or worsen these autoimmune diseases.     

H-transfer rates in ion-neutral complexes versus those in intact aliphatic ions

The relative rates of H-transfer between partners in ion-neutral complexes were compared with those in intramolecular rearrangements using results of first differential photoionization mass spectrometry measurements. Complex-mediated H-transfers are inferred to have rates of the same order as those for intramolecular hydrogen rearrangements, suggesting a similar range of motion of the reactive sites in both types of reactions. It is also concluded that at their fastest H-transfers take place between the partners in ion-neutral complexes within at most the time of several rotations of the partners in the complexes. Copyright 1999 John Wiley & Sons, Ltd.     

New high-energy luminescence bands from Co2+ in ZnSe

Three sharp absorption features in the energy range 2.36–2.55 eV have been detected in the transmission spectrum of Co-diffused ZnSe, and a number of luminescence transitions originating from the lowest of these states at 2.361 eV have been observed. Photoluminescence excitation spectra prove that these are high energy excited states of the Co²⁺_Zn impurity, a conclusion confirmed by comparison of measured and predicted luminescence energies. This represents the first identification of luminescence branching from a higher excited state of a transition metal ion in any semiconductor. The sharp, weakly phonon-coupled transitions involve either intra-impurity excitation or transitions from the impurity to localised states split off from a minimum in the conduction band. The implications of these observations for the mechanism of host-impurity energy transfer and for the nature of the excited state wavefunctions are discussed.     

Lysozyme binding to poly(4-vinyl-N-alkylpyridinium bromide)

The adsorption behavior of polycations at ionic strengths (I) ranging from 0.001 to 0.1 onto silicon wafers was studied by means of ellipsometry, contact angle measurements and atomic force microscopy (AFM). Polycations chosen were bromide salts of poly(4-vinylpyridine) N-alkyl quaternized with linear aliphatic chains of 2 and 5 carbon atoms, QPVP-C2 and QPVP-C5, respectively. Under I=0.001 the reduction of screening effects led to low adsorbed amounts of QPVP-C2 or QPVP-C5 (1.0±0.1 mg/m²), arising from the adsorption of extended chains. Upon increasing I to 0.1, screening effects led to conformational changes of polyelectrolyte chains in solution and to higher adsorbed amount values (1.9±0.2 mg/m²). Advancing contact angle θ_a measurements performed with water drops onto QPVP-C2 and QPVP-C5 adsorbed layers varied from (45±2)° to (50±5)°, evidencing the exposure of both hydrophobic alkyl groups and charged moieties. The adsorption of lysozyme (LYZ) molecules to QPVP-C5 layers was more pronounced than to QPVP-C2 films. Antimicrobial effect of LYZ bound to QPVP-C2 or QPVP-C5 layers or to Si wafers was evaluated with enzymatic assays using Micrococcus luteus as substrates. The adsorption behavior of QPVP-C2 and QPVP-C5 at the water–air interface was studied by means of surface tension measurements. Only QPVP-C5 was able to reduce water surface tension. Mixtures of LYZ and QPVP-C5 were more efficient in reducing surface tension than pure LYZ solution, evidencing co-adsorption at liquid–air interface. Moreover, antimicrobial action observed for mixtures of LYZ and QPVP-C5 was more pronounced than that measured for pure LYZ. Hydrophobic interaction between LYZ and QPVP-C5 in solution seems to drive the binding and to preserve LYZ secondary structure.     

On the quantum polarization and entanglement of superpositions of two two-mode coherent states

This work discusses the entanglement and quantum polarization of superpositions of two-mode coherent states of the types |ψ₁〉 = N₁(|α, β〉 + |β, α〉) and |ψ₂〉 = N₂(|−α, −α〉 + |α, α〉). We use the concurrence to measure their entanglements and the quantum Stokes parameters and the Q function in order to analyze their polarization and degree of polarization.     

Wrapped branes as qubits

Recent work has established a correspondence between the tripartite entanglement measure of three qubits and the macroscopic entropy of the four-dimensional 8-charge STU black hole of supergravity. Here we consider the configurations of intersecting D3-branes, whose wrapping around the six compact dimensions T6 provides the microscopic string-theoretic interpretation of the charges, and associate the three-qubit basis vectors |ABC>, (A, B, C=0 or 1) with the corresponding 8 wrapping cycles. In particular, we relate a well-known fact of quantum information theory, that the most general real three-qubit state can be parameterized by four real numbers and an angle, to a well-known fact of string theory, that the most general STU black hole can be described by four D3-branes intersecting at an angle.     

Bone repair in rat mandible by rhBMP-2 associated with two carriers

This study evaluated the quantity and quality of newly formed bone, stimulated by rhBMP-2 in combination with monoolein or chitosan gel as carriers, in critical bone defects created in 36 Wistar rat mandibles. Two weeks after surgery, the animals were anesthetized with 37.5% urethane submitted to perfusion and the hemi-mandibles removed for histological and histomorphometrical analysis. The results showed that there was a statistical difference between groups of animals receiving or not rhBMP-2 (p<0.05). Newly formed bone was more intense in the occlusal region, followed by the basal and middle regions, respectively. Both carriers, monoolein and chitosan gels were adequate for defect filling and control of protein release.     

Sonoelastographic imaging of interference patterns for estimation of shear velocity distribution in biomaterials

The authors have recently demonstrated the shear wave interference patterns created by two coherent vibration sources imaged with the vibration sonoelastography technique. If the two sources vibrate at slightly different frequencies omega and omega+deltaomega, respectively, the interference patterns move at an apparent velocity of (deltaomega/2omega)upsilon(shear), where upsilon(shear) is the shear wave speed. We name the moving interference patterns "crawling waves." In this paper, we extend the techniques to inspect biomaterials with nonuniform stiffness distributions. A relationship between the local crawling wave speed and the local shear wave velocity is derived. In addition, a modified technique is proposed whereby only one shear wave source propagates shear waves into the medium at the frequency omega. The ultrasound probe is externally vibrated at the frequency omega-deltaomega. The resulting field estimated by the ultrasound (US) scanner is proven to be an exact representation of the propagating shear wave field. The authors name the apparent wave motion "holography waves." Real-time video sequences of both types of waves are acquired on various inhomogeneous elastic media. The distribution of the crawling/holographic wave speeds are estimated. The estimated wave speeds correlate with the stiffness distributions.     

Generalization of the concept of continuous function and homeomorphism

Summary We give here a generalization of the concept of continuous function and homeomorphism which seems to be useful in some questions of topology. For instance, applications are given here to separation theorems and to Čech homology theory. This research was supported by the Air Force Office of Scientific Research.