Baryon pairs production ine + e − annihilation at\sqrt s = 2.4 GeV

Search for baryon pairs production ine ⁺ e ^? annihilation at \(\sqrt s = 2386 MeV\) is reported. The data relate to a luminosity of 161 nb^?1 collected by the DM2 experiment at DCI, the Orsay colliding ring. First measurements of directe ⁺ e ^? annihilation into \(\Lambda \bar \Lambda \) and ofe ⁺ e ^?→ \(p\bar p\) at this energy are presented. First observation of a goode ⁺ e ^?→ \(n\bar n\) candidate is reported and upper limits are given fore ⁺ e ^?→ \(n\bar n, \Lambda \bar \sum ^0 + c.c.\) and \(\Sigma ^0 \bar \Sigma ^0 \) .     

Quantization on curved surfaces

After a short review of the existing methods for quantization of curved manifolds, the free particle motions or the so‐called geodesic flows on axisymmetrical prolate and oblate ellipsoids are quantized using the isomorphism established by Neumann of these systems and the harmonic oscillator restricted to the unit sphere. © 2002 Wiley Periodicals, Inc. Int J Quantum Chem, 2002     

Equilibrium Configurations of Lipid Bilayer Membranes and Carbon Nanostructures

The present article concerns the continuum modelling of the mechanical behaviour and equilibrium shapes of two types of nano-scale objects: fluid lipid bilayer membranes and carbon nanostructures. A unified continuum model is used to handle four different case studies. Two of them consist in representing in analytic form cylindrical and axisymmetric equilibrium configurations of single-wall carbon nanotubes and fluid lipid bilayer membranes subjected to uniform hydrostatic pressure. The third one is concerned with determination of possible shapes of junctions between a single-wall carbon nanotube and a flat graphene sheet or another single-wall carbon nanotube. The last one deals with the mechanical behaviour of closed fluid lipid bilayer membranes (vesicles) adhering onto a flat homogeneous rigid substrate subjected to micro-injection and uniform hydrostatic pressure.     

DNA Damage Clustering after Ionizing Radiation and Consequences in the Processing of Chromatin Breaks

Charged-particle radiotherapy (CPRT) utilizing low and high linear energy transfer (low-/high-LET) ionizing radiation (IR) is a promising cancer treatment modality having unique physical energy deposition properties. CPRT enables focused delivery of a desired dose to the tumor, thus achieving a better tumor control and reduced normal tissue toxicity. It increases the overall radiation tolerance and the chances of survival for the patient. Further improvements in CPRT are expected from a better understanding of the mechanisms governing the biological effects of IR and their dependence on LET. There is increasing evidence that high-LET IR induces more complex and even clustered DNA double-strand breaks (DSBs) that are extremely consequential to cellular homeostasis, and which represent a considerable threat to genomic integrity. However, from the perspective of cancer management, the same DSB characteristics underpin the expected therapeutic benefit and are central to the rationale guiding current efforts for increased implementation of heavy ions (HI) in radiotherapy. Here, we review the specific cellular DNA damage responses (DDR) elicited by high-LET IR and compare them to those of low-LET IR. We emphasize differences in the forms of DSBs induced and their impact on DDR. Moreover, we analyze how the distinct initial forms of DSBs modulate the interplay between DSB repair pathways through the activation of DNA end resection. We postulate that at complex DSBs and DSB clusters, increased DNA end resection orchestrates an increased engagement of resection-dependent repair pathways. Furthermore, we summarize evidence that after exposure to high-LET IR, error-prone processes outcompete high fidelity homologous recombination (HR) through mechanisms that remain to be elucidated. Finally, we review the high-LET dependence of specific DDR-related post-translational modifications and the induction of apoptosis in cancer cells. We believe that in-depth characterization of the biological effects that are specific to high-LET IR will help to establish predictive and prognostic signatures for use in future individualized therapeutic strategies, and will enhance the prospects for the development of effective countermeasures for improved radiation protection during space travel.     

Stabilität einer elliptischen Zylinderschale unter Torsion

Übersicht Die vorliegende Arbeit behandelt die statische Stabilität einer elliptischen, dünnwandigen, isotropen, elastischen Zylinderschale unter Torsion bei vier verschiedenen Arten von Randbedingungen. Die Lösung wird mit Hilfe des Bubnow-Galerkin-Verfahrens gesucht. Manche Ergebnisse der numerischen Lösung sind graphisch dargestellt. Sie zeigen, daß sich die minimale kritische Last bei wachsender Exzentrizität reduziert.

---

Summary The paper deals with the static instability of an elliptic, thin-walled, isotropic, elastic cylindrical shell under torsion for four different sets of boundary conditions. The solution is based on the method of Bubnov-Galerkin. Some numerical results are presented on diagrams. They show that the smallest critical loading diminishes when the eccentricity of the cross-section increases.

     

An approach for decomposition of finite rotations

Based on Lie groups theory, this work considers the problem of decomposition of a given rotation into three successive finite rotations with prescribed in advance axes. (© 2012 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)     

Classical motions of infinitesimal rotators on Mylar balloons

This paper starts with the derivation of the most general equations of motion for the infinitesimal rotators moving on arbitrary two-dimensional surfaces of revolution. Both geodesic and geodetic (i.e., without any external potential) equations of motion on surfaces with nontrivial curvatures that are embedded into the three-dimensional Euclidean space are discussed. The Mylar balloon as a concrete example for the application of the scheme was chosen. A new parameterization of this surface is presented, and the corresponding equations of motion for geodesics and geodetics are expressed in an analytical form through the elliptic functions and elliptic integrals. The so-obtained results are also compared with those for the two-dimensional sphere embedded into the three-dimensional Euclidean space for which it can be shown that the geodesics and geodetics are plane curves realized as the great and small circles on the sphere, respectively.     

Self-Organization of Magnetic Nanoparticles and Inclusion of Hydrogen by Borohydride Reduction

Summary.  Different structures of the interglobular space or voids between self-organized nanoparticles lead to differences in the measurable magnetic properties of single-domain particle chains of similar composition, grain size, and amorphous structure of the single globules. The volumes and radii of nanoparticles obtained by application of a magnetic field (3 to 15 nm) are larger than those determined without application of a magnetic field during the borohydride reduction process. Two types of hydrogen containing nanotubes with diameters of up to 2 (small-size containers) and 5 nm (large-size containers) are produced using as a driving force the domain wall formation energy between ferromagnetic nanoparticles with quantum size effected dimensions prepared by this reduction method at room temperature and ambient atmosphere. Nanoscale hydrogen containers can be used instead of MeH nanoparticle electrodes as perfect energy charge transfer media of high efficiency (close to 100%) using Li ion electrolytes. No influence on the electrode temperature and no participation of OH⁻ and H₂O in the main charge/discharge transfer reactions were observed. Received October 25, 2001. Accepted (revised) January 3, 2002