Ring-Opening 1-Amino-3-aminomethylation of Donor–Acceptor Cyclopropanes via 1,3-Diazepanes

The first ring-opening reaction of donor–acceptor cyclopropanes to give diamines is reported. For this reaction, a 1,3-bisfunctionalization was developed using cyclopropanes, triazinanes, and Sc(OTf)₃ as the catalyst, followed by treatment with acid. The reaction proceeds under very mild conditions and tolerates many functional groups. Moreover, a library of various 1,3-diazepanes, which arise as intermediates of the first formal aza-[4+3]-cycloaddition reaction with donor–acceptor cyclopropanes, was synthesized.     

Vibrations of a taut string and torsional vibration of a gun barrel under the influence of a moving mass

Vibration of a string under a moving mass is considered. Owing to the interplay between inertial forces and the string tension this problem shows some differences from that of a travelling force. The torsional vibration of a gun barrel induced by the spin-up of a bullet, being of ballistic interest, is also treated.     

Lipopolysaccharide removal by a peptide-functionalized surface

Five peptides: BPI(85-109); CAP18(106-137); endotoxin inhibitor (EI); GQ33 and GQ33C, derived from lipopolysaccharide (LPS)-binding molecules were investigated for LPS-binding ability with a view to a potential use in extracorporeal therapy. The surface plasmon resonance technique (SPR) was used to monitor the interaction between LPS in solution and the surface-immobilized peptides. The peptides were covalently bound to a model dextran surface via inherent amino groups or via terminally introduced cysteine residues. The results showed that the binding efficacy and binding stability of the peptides varied greatly. The CAP18(106-137) peptide, which exhibited the highest binding efficacy and binding stability, was also immobilized on a poly(ethylene imine)-poly(ethylene glycol) (PEI-PEG) surface through maleimide-terminal PEG. The binding efficacy of the CAP18(106-137) peptide was not significantly affected by the different immobilization methods used in the attachment to a dextran or a PEI-PEG surface. LPS bound selectively to CAP18(106-137) and showed very low unspecific binding to the PEI-PEG surface layer. The EI peptide proved to have a reasonably good binding capacity but a less stable interaction with LPS. The other peptides exhibited much poorer binding efficacy. We believe that the results presented in this work can be of practical value for the development of extracorporeal treatment of patients suffering from septic shock.     

Separation of hydroxy acids by ion exchange chromatography

Factors affecting the Chromatographic separation of hydroxy acids by means of anion exchange resins in the borate form have been studied. With the acids studied the separation factor increases for a decreased borate concentration in the eluant. With complicated mixtures it is recommended to employ stepwise elution with solutions of increasing concentration.     

Electromagnetic wave collapse in a radiation background

The nonlinear interaction, due to quantum electrodynamical (QED) effects between an electromagnetic pulse and a radiation background, is investigated by combining the methods of radiation hydrodynamics with the QED theory for photon-photon scattering. For the case of a single coherent electromagnetic pulse, we obtain a Zakharov-like system, where the radiation pressure of the pulse acts as a driver of acoustic waves in the photon gas. For a sufficiently intense pulse and/or background energy density, there is focusing and the subsequent collapse of the pulse. The relevance of our results for various astrophysical applications are discussed.     

Decay of63Zn

Investigation of the 38.8 min decay of⁶³Zn has resulted in 31 gamma-ray transitions in⁶³Cu. New levels not earlier reported inΒ ⁺-decay of⁶³Zn, but found in nuclear reactions, are suggested at 2,010.9 and 3,101 keV. It is assumed that the excited core model generates a multiplet of levels at 669.75 keV (1/2^?), 962.1 keV (5/2^?), 1,327.1 keV (7/2^?) and 1,546.6 keV (3/2^?). Intensities for intramultiplet transitions were found to be: 219.4 keV, <0.004 (in units of 200 for annihilation radiation), 292.4 keV, <0.004, 365.0 keV, 0.03±0.03, 584.4 keV, <0.005, and 876.8 keV, <0.005.     

Sub-nanosecond lifetimes in Te

The half-lives of the 1776.8 keV 6⁺ level and the 2497.3 keV 7^? level in ¹²⁶Te are measured by registering β-γ coincidences in the decay of ¹²⁶Sb. The results are $\text{T}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext><mtext>(1776.8)\; =\; 66\pm 3</mtext><mtext>ps</mtext>}}$ and $\text{T}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext><mtext>(2497.3)\; =\; 152\pm 5\; </mtext><mtext>ps</mtext>}}$. The collective strength of the 6⁺ → 4⁺ transition depopulating the 1776.8 keV state is estimated. An additional half-life of 0.36±0.06 ns is found but not definitely assigned in the level scheme.