Energies and collapse times of symmetric and symmetry-breaking states of finite systems with a U(1) symmetry.

We study quantum systems of volume V, which will exhibit the breaking of a U(1) symmetry in the limit of V-->infinity, when V is large but finite. We estimate the energy difference between the "symmetric ground state" (SGS), which is the lowest-energy state that does not break the symmetry, and a "pure phase vacuum" (PPV), which approaches a symmetry-breaking vacuum as V-->infinity. Under some natural postulates on the energy of the SGS, it is shown that PPVs always have a higher energy than the SGS, and we derive a lower bound of the excess energy. We argue that the lower bound is O(V0), which becomes much larger than the excitation energies of low-lying excited states for a large V. We also discuss the collapse time of PPVs for interacting many bosons. It is shown that the wave function collapses in a microscopic time scale, because PPVs are not energy eigenstates. We show, however, that for PPVs the expectation value of any observable, which is a finite polynomial of boson operators and their derivatives, does not collapse for a macroscopic time scale. In this sense, the collapse time of PPVs is macroscopically long.

Robustness of wave functions of interacting many bosons in a leaky Box

We study the robustness, against the leakage of bosons, of wave functions of interacting many bosons confined in a finite box by deriving and analyzing a general equation of motion for the reduced density operator. We identify a robust wave function that remains a pure state, whereas other wave functions, such as the Bogoliubov's ground state and the ground state with a fixed number of bosons, evolve into mixed states. Although these states all have the off-diagonal long-range order, and the same energy, we argue that only the robust state is realized as a macroscopic quantum state.

Synthesis and in vitro activity of a new carbapenem, RS-533.

The synthesis and in vitro antimicrobial activity of a new synthetic carbapenem, (5R,6S)-6-[(R)-1-hydroxyethyl]-2-[(S)-1-acetimidoylpyrrolidin -3-ylthio]-1-carbapen-2-em-3-carboxylic acid (RS-533), are described. The MIC values of related penems and carbapenems are also given for comparison with those of the new carbapenem.

Potent cephalosporinase inhibitors: 7 beta-[2-(1, 3-dithiolan-2-ylidene) acetamido] cephalosporins and related compounds.

Cephalosporins possessing a 1, 3-dithiolane, 1, 3-dithiane, or 1, 3-dithietane ring on their 7 beta-substituents showed potent inhibitory activity against cephaloridine hydrolysis by cephalosporinases purified from proteus morganii, Proteus rettgeri, and Proteus inconstans, which were not inhibited by clavulanic acid, a well-known beta-lactamase inhibitor. The mode of inhibition was competitive. The dithiolane cephalosporins themselves were stable against hydrolysis by the beta-lactamases tested. A combination of a dithiolane cephalosporin and cephaloridine synergistically inhibited in vitro growth of strains of P. morganii, P. rettgeri, P. inconstans, Enterobacter aerogenes, Enterobacter cloacae, and Serratia marcescens.

Stereo-specific synthesis of 3-trifluoromethylcephalosporin derivative by microbial acylase.

Cephalosporin acylase (EC 3.5.1.11) obtained from Kluyvera citrophila ATCC 21285 was found to catalyze synthesis of 7-[2-(2-thienyl)acetamido]-3-trifluoromethyl-3-cephem-4-carboxylic acid from methyl thienylacetate and dl-7-amino-3-trifluoromethyl-3-cephem-4-carboxylic acid. The enzymatically-synthesized compound showed [alpha]25 D + 42.7 degrees (c 0.058, MeOH) and its biological activity was about twice as much as that of racemic 7-[2-(2-thienyl)acetamidol]-3-trifluoromethyl-3-cephem-4-carboxylic acid chemicall synthesized. As a result, N-acylation by this enzyme was demonstrated to be asymmetric synthesis.