Synthetic studies of polyene macrolides,synthesis of a C29–37 fragment for amphotericin B and nystatin

An enantioselective synthesis of a C29–37 fragment common to both amphotericin B $\text{1}$ and nystatin $\text{2}$ is described from ethyl 3(S)-hydroxybutanote.     

Synthetic studies of trichothecenes,an enantioselective synthesis of a C-ring precursor of anguidine

An enantioselective synthesis of a cyclopentanoid C-ring precursor $\text{1}$$\text{9}$ of anguidine $\text{3}$, a representative trichothecene with antitumor activity, from 2-allyl-2-methylcyclopentane-1,3-dione is described.     

Chiral cyclohexanoid synthetic precursors via asymmetricmicrobial reduction of prochiral cyclohexanediones

Microbial reduction of various 2,2-disubstituted-1,3-cyclohexanediones with bakers' yeast provides efficient access to chiral cyclohexanoid synthetic precursors.     

3D configuration of mandibles and controlling muscles in rove beetles based on micro-CT technique

X-ray micro-CT is a powerful tool to visualize without damage details of the inner structures of beetles, the largest order of insects with a hard external skeleton. This contribution shows the three-dimensional (3D) reconstruction of the head morphology of three rove beetle species (Insecta, Coleoptera, Staphylinidae)—Noddia sp., Creophilus maxillosus, and Hesperosoma sp.—using X-ray microtomography at a spatial resolution of 6 μm. The details of skeletal muscle fiber insertions are described, giving a comprehensive overview of mandible mobility and organization. With the support of 3D rendering, we discuss the relationship among the mandible forms, the development of the muscles controlling the movement, and the head morphology. The well-developed posterior part of the head capsule is always accompanied by a well-developed mandible, a large adductor muscle, and a large apodeme for the wide areas of the muscle fiber attachment. In Noddia sp., muscles connected to the posterolateral angle of the head capsule are mainly short muscles, whereas in Creophilus maxillosus, the latter are mainly long muscles, and in Hesperosoma sp. no mandible adductor muscle fibers are present on the posterolateral angle of the head capsule. These results offer new invaluable information regarding the biting functions of beetle mandibles and the trend of their morphological change during their long-term evolution.     

Reduction of a polling network to a single node

We consider a discrete-time tree network of polling servers where all packets are routed to the same node (called node 0), from which they leave the network. All packets have unit size and arrive from the exterior according to independent batch Bernoulli arrival processes. The service discipline of each node is work-conserving and the service discipline of node 0 has to be HoL-based, which is an additional assumption that is satisfied by, a.o., m _i -limited service, exhaustive service, and priority disciplines. Let a type i packet be a packet that visits queue i of node 0. We establish a distributional relation between the number of type i packets in the network and in a single station system, and we show equality of the mean end-to-end delay of type i packets in the two systems. Essentially this reduces an arbitrary tree network to a much simpler system of one node, while preserving the mean end-to-end delay of type i packets.      

Baryon distributions in ultrarelativistic nucleus-nucleus collisions

We have measured distributions in transverse momentum and rapidity of protons from interactions of 14.6 GeV/nucleon²⁸Si projectiles with targets of Al and Pb. The transverse momentum spectra exhibit a thermal shape with a rapidity dependent temperature parameter. For very central or violent collisions the proton rapidity distributions exhibit the large rapidity shifts and (for Si+Al) a peak at midrapidity as required for full stopping.     

Particle-hole symmetry and the effect of disorder on the Mott-Hubbard insulator

The understanding of the interplay of electron correlations and randomness in solids is enhanced by demonstrating that particle-hole ( p-h) symmetry plays a crucial role in determining the effects of disorder on the transport and thermodynamic properties of the half-filled Hubbard Hamiltonian. We show that the low-temperature conductivity decreases with increasing disorder when p-h symmetry is preserved, and shows the opposite behavior, i.e., conductivity increases with increasing disorder, when p-h symmetry is broken. The Mott insulating gap is insensitive to weak disorder when there is p-h symmetry, whereas in its absence the gap diminishes with increasing disorder.