Quantum phase transition in the magnetic-field-induced normal state of optimum-doped high-Tc cuprate superconductors at low temperatures.

A 60 T magnetic field suppresses the superconducting transition temperature T_{c} in La_{2-p}Sr_{p}CuO_{4} to reveal a Hall number anomaly, which develops only at temperatures below zero-field T_{c} and peaks at the exact location of p that maximizes T_{c}. The anomaly bears a striking resemblance to observations in Bi_{2}Sr_{2-x}La_{x}CuO_{6+delta}, suggesting a normal-state phenomenology common to the cuprates that underlies the high-temperature superconducting phase. The peak is ascribed to a Fermi surface reconstruction at a quantum phase transition near optimum doping that is coincident with the collapse of the pseudogap state.

Nanoscale friction: kinetic friction of magnetic flux quanta and charge density waves.

In analogy with the standard macroscopic friction, here we present a comparative study of the friction force felt by moving vortices in superconductors and charge density waves. Using experiments and a model for this data, our observations (1) provide a link between friction at the micro- and macroscopic scales, (2) explain the roundness of the static-kinetic friction transition in terms of thermal fluctuations, particle interactions, and system size (critical-phenomena view), and (3) explain the crossing of the kinetic friction F(k) versus velocity V for our pristine (high density of very weak defects) and our irradiated samples (with lower density of deeper pinning defects).

Two-stage spin-flop transitions in the S = 1/2 antiferromagnetic spin chain BaCu(2)Si(2)O(7).

Two-stage spin-flop transitions are observed in the quasi-one-dimensional antiferromagnet BaCu(2)Si(2)O(7). A magnetic field applied along the easy axis induces a spin-flop transition at 2.0 T followed by a second transition at 4.9 T. The magnetic susceptibility indicates the presence of Dzyaloshinskii-Moriya (DM) antisymmetric interactions between the intrachain neighboring spins. We discuss a possible mechanism whereby the geometrical competition between DM and interchain interactions, as discussed for the two-dimensional antiferromagnet La(2)CuO(4), causes the two-stage spin-flop transitions.

Unusual magnetic susceptibility anisotropy in untwinned La2-xSr(x)CuO4 single crystals in the lightly doped region.

We present a study of the magnetic susceptibility chi in carefully detwinned La 2-xSr(x)CuO4 single crystals in the lightly doped region (x = 0-0.03), which demonstrates a remarkable in-plane anisotropy of the spin system. This anisotropy, chi(a)/chi(b), is found to persist after the long-range antiferromagnetic (AF) order is destroyed by hole doping, suggesting that doped holes break the AF order into domains in which the spin alignment is kept essentially intact. It turns out that the freezing of the spins taking place at low temperatures is also notably anisotropic, implying that the "spin-glass" feature is governed by the domain structure as well.

Energy separation of single-particle and continuum states in an S = 1/2 weakly coupled chains antiferromagnet

Inelastic neutron scattering is used to study transverse-polarized magnetic excitations in the quasi-one-dimensional S = 1/2 antiferromagnet BaCu2Si2O7, where the saturation value for the Neel order parameter is m(0) = 0.12&mgr;(B) per spin. At low energies the spectrum is totally dominated by resolution-limited spin-wave-like excitations. An excitation continuum sets in above a well-defined threshold frequency. Experimental results are discussed in the context of current theories for weakly interacting quantum half-integer-spin chains.

Synthesis and antifungal activity of novel thiazole-containing triazole antifungals. II. Optically active ER-30346 and its derivatives.

A series of novel thiazole-containing triazole antifungals was synthesized and evaluated for antifungal activity against a variety of clinically isolated pathogenic fungi in vitro and against systemic candidosis in vivo. These compounds showed potent antifungal activities in vitro and in vivo. In particular, (2R,3R)-3-[4-(4-cyanophenyl)thiazol-2-yl]-2-(2,4- difluorophenyl)-1-(1H-1,2,4-triazol-1-yl)-2-butanol (12g; ER-30346) showed potent and well-balanced in vitro activities and potent in vivo efficacy, and had a good safety profile.

Synthesis and antifungal activity of novel thiazole-containing triazole antifungals.

A new series of thiazole-containing triazole antifungals was synthesized and evaluated for antifungal activity against a variety of clinically isolated pathogenic fungi in vitro and against systemic candidosis in vivo. Among these compounds, (+/-)-1-(2,4-difluorophenyl)-1-[4-(2,4-difluorophenyl) thiazol-2-yl]-2-(1H-1,2,4-triazol-1-yl)ethanol (ER24161) showed the most potent and well-balanced in vitro activities and excellent in vivo efficacy. We also achieved an enantioselective synthesis of the more potent enantiomer of ER-24161.

Studies on orally active cephalosporins. I. Synthesis and structure-activity relationships of new 3-substituted carbamoyloxymethyl cephalosporins.

The synthesis and antibacterial activities of 7 beta-[2-(2-aminothiazol-4-yl)-2-hydroxyiminoacetamido]-3-N,N - dimethylcarbamoyloxymethyl-3-cephem-4-carboxylic acid (E1100) and its analogs are described, as well as oral absorbability and in vivo activities of the 1-(isopropoxycarbonyloxy)ethyl ester (E1101) and its analogous esters. The introduction of acyclic and cyclic lower alkyl groups at the N-position of 3-carbamoyloxymethyl cephems influences antibacterial activities, especially against H. influenzae, and oral absorbability of their prodrug esters. The structure-activity relationships are also discussed.

Studies on orally active cephalosporins. II. Synthesis and structure-activity relations of new [(E) or (Z) 3-substituted carbamoyloxy]-1-propenyl cephalosporins.

In an effort to find a new oral cephalosporin with well-balanced antibacterial spectrum, good oral absorbability and long plasma half-life, a series of oxyimino aminothiazolyl 3-[(E)- or (Z)-N-substituted carbamoyloxy]propenyl cephems was synthesized and evaluated for antibacterial activity and oral absorbability. The substituents of the carbamoyloxy group affected their in vitro activity and bioavailability after oral administration of their pivaloyloxymethyl esters at the C-4 position. The compound possessing an N,N-dimethylcarbamoyloxy moiety at the C-3 position showed good oral absorption and well-balanced antibacterial activity. In this report, the structure-activity relationships and the structure-oral absorbability relationships of 3-(N-substituted carbamoyloxy)-propenyl cephems are described.

[CT appearance of uterine adenomyosis].

CT findings in 37 cases with pathological diagnosis of uterine adenomyosis were reviewed retrospectively. The attenuation coefficient of adenomyosis is almost same as normal parenchyma on both plain and enhanced CT. The margin was obscure except for one case. In focal type, deviation of the endometrium and deformity of the uterus may be a clue to the detection of adenomyosis. But differential diagnosis of adenomyosis from leiomyoma with ill-defined margin was very difficult. In diffuse type, the uterine body is swollen without deviation of the endometrium. This type can be diagnosed if the endometrium identified clearly.

[Management of post-term pregnancy].

Simple titration of urinary estriol and of serum human placental lactogen (HPL) has recently proved valuable in the assessment of feto-placental function, and the non-stress test (NST), the contraction-stress test (CST), and other fetal reserve tests are now routinely used in the management of post-term pregnancy. Major progress has also been made in labor induction using prostaglandin and DHAS. Despite these advances, however, the prognosis of post-term fetus has not improved during the past five years at our department. Our statistical data indicate room for improvement in the management of post-term pregnancy, but independently of new methods of fetal assessment or of labor induction. The management of post-term pregnancy appears to have entered a new stage of development. Ultrasonic echography has made it possible accurately to estimate gestational age, and hence the date of conception, early in pregnancy and thus to exclude false post-term pregnancies. The post-term pregnancy rate was once as high as 7%. More than half of these cases were false and were often subject to unnecessary induction of labor. Echographic screening and correction of date of conception have now reduced the true incidence of post-term pregnancy to between 1.5% and 3.1%. Echographic screening should therefore be performed for this purpose whenever possible. The diagnosis of oligohydramnios has also been facilitated by ultrasonic echography for the semiquantitative measurement of amniotic fluid. It has been reported, for example, that the volume of amniotic fluid tends to decrease after the 38th week of pregnancy.(ABSTRACT TRUNCATED AT 250 WORDS)