Distribution of scattering matrix elements in quantum chaotic scattering.

Scattering is an important phenomenon which is observed in systems ranging from the micro- to macroscale. In the context of nuclear reaction theory, the Heidelberg approach was proposed and later demonstrated to be applicable to many chaotic scattering systems. To model the universal properties, stochasticity is introduced to the scattering matrix on the level of the Hamiltonian by using random matrices. A long-standing problem was the computation of the distribution of the off-diagonal scattering-matrix elements. We report here an exact solution to this problem and present analytical results for systems with preserved and with violated time-reversal invariance. Our derivation is based on a new variant of the supersymmetry method. We also validate our results with scattering data obtained from experiments with microwave billiards.

Distribution of proper delay times in quantum chaotic scattering: a crossover from ideal to weak coupling.

The probability distribution of the proper delay times during scattering on a chaotic system is derived in the framework of the random matrix approach and the supersymmetry method. The result obtained is valid for an arbitrary number of scattering channels as well as arbitrary coupling to the energy continuum. The case of statistically equivalent channels is studied in detail. In particular, the semiclassical limit of an infinite number of weak channels is paid appreciable attention.

Reducing nonideal to ideal coupling in random matrix description of chaotic scattering: application to the time-delay problem.

We write explicitly a transformation of the scattering phases reducing the problem of quantum chaotic scattering for systems with M statistically equivalent channels at nonideal coupling to that for ideal coupling. Unfolding the phases by their local density leads to universality of their local fluctuations for large M. A relation between the partial time delays and diagonal matrix elements of the Wigner-Smith matrix is revealed for ideal coupling. This helped us in deriving the joint probability distribution of partial time delays and the distribution of the Wigner time delay.

Effects of beta-adrenergic blockade on ventilation and gas exchange during incremental exercise.

Controversy exists concerning the effects of acute beta-adrenergic blockade on ventilation during exercise. Hence, the purpose of this study was to determine the effects of acute beta blockade on ventilation and gas exchange during incremental exercise. Nine male subjects underwent incremental exercise on a cycle ergometer (30 W.min-1) to exhaustion, with one trial being performed 60 min after the subject ingested propranolol hydrochloride (Inderal 1 mg.kg-1 BW) while the second test served as control. The treatment order was counterbalanced to preclude any ordering effect on the results, and 1 week separated the tests. Ventilation and gas exchange were monitored by open circuit techniques. No difference (p greater than 0.05) existed in VE, % Hb sat, VCO2, ventilatory threshold, and VE/VCO2 between treatments at the same exercise stage. VO2max was lowered from 3.82 to 3.26 l.min-1 (p less than 0.05) and HRmax was reduced from 190 to 150 bpm (p less than 0.05) as a result of beta blockade. These data suggested that acute beta blockade had no effect on exercise ventilation, but decreased HRmax at comparable work rates. In addition, VO2max and exercise time to exhaustion were hindered, probably due to beta blockade limitation of HRmax, and, thus, oxygen transport.

Effects of beta-adrenergic blockade on ventilation and gas exchange during the rest to work transition.

The purpose of these experiments was to determine the effects of acute beta-blockade on the kinetics of oxygen uptake (VO2), expired carbon dioxide (VCO2), and expired ventilation (VE) in the transition from rest to submaximal exercise. Six male subjects exercised for 6 min on a cycle ergometer (60 W) initiated as a square wave from rest on two occasions. The beta-blockade experiment began 60 min after the subject ingested propranolol hydrochloride (1 mg.kg-1 BW) while the second experiment served as control with the treatment order counterbalanced. Ventilation and gas exchange were monitored by open circuit techniques and the data were modeled with a single-component exponential function using a time delay. No differences existed (p greater than 0.05) in the steady state VO2, VCO2, or VE nor the kinetics of VCO2 and VE between treatments. However, the rate of adaptation of VO2 toward steady state was significantly slowed (p less than 0.05) with beta-blockade. These data suggest that acute beta blockade results in diminished VO2 kinetics in the transition from rest to steady-state exercise. We hypothesize that the mechanism to explain this finding is a slowed time course of cardiac output adjustment at the beginning of exercise.

Woodman's disease: hypersensitivity pneumonitis from cutting live trees.

A 28-year-old man developed multiple episodes of fever, cough, shortness of breath, and leukocytosis several hours after cutting live oak and maple trees. Fungal cultures of wood chips from oak and maple trees were positive for Penicillium (three species), Paecilomyces sp., Aspergillus niger, Aspergillus sp., and Rhizopus sp. Gel-immunodiffusion studies demonstrated serum precipitins to extracts of oak chips, Penicillium sp., and Paecilomyces sp., and suggested that Penicillium sp. and Paecilomyces sp. shared cross-reactive antigens that were the significant antigens in the oak chips. ELISA studies demonstrated elevated serum levels of IgG to an oak chip extract, inhibition of that ELISA by preincubation of serum with Penicillium sp., and absence of elevated IgG levels to an extract of freshly cut oak wood that had been stripped of bark to minimize mold contamination. The case analysis indicates that the patient likely had hypersensitivity pneumonitis on exposure to Penicillium sp., when he was cutting trees, and identifies cutting live trees as another occupational exposure that may cause hypersensitivity pneumonitis.

Effect of clavulanic acid on the susceptibility of clinical anaerobic bacteria to ticarcillin: a multicenter study.

Over 2,000 recent clinical isolates of anaerobic bacteria were tested at five medical centers for susceptibility to ticarcillin, ticarcillin plus clavulanic acid, clindamycin, and metronidazole. At 64 micrograms/ml, ticarcillin inhibited 92% of all isolates, but 98% were inhibited at this concentration when 2 micrograms/ml of clavulanic acid was added. With different Bacteroides species, clavulanic acid reduced ticarcillin MICs 2- to 32-fold; other anaerobic species were not significantly affected.

Prolonged evaluation of patients with corticosteroid-dependent asthma stage of allergic bronchopulmonary aspergillosis.

Eight cases with stage IV allergic bronchopulmonary aspergillosis (ABPA) (corticosteroid-dependent asthma stage) were observed for a total of 82 patient years with individual patients observed for 7 to 19 years (mean 10.2) years. One case is the first case of ABPA diagnosed in the United States in 1967. A second case has been observed through four stages of ABPA. None of these eight cases has demonstrated pulmonary deterioration by clinical, chest roentgenogram, or pulmonary function analysis. After diagnosis, the maintenance dose of prednisone in seven of eight cases was a low to moderate dose alternate-day prednisone. These results suggest that continuous observation and management of episodes of pulmonary consolidation or asthma exacerbations may prevent the progression of ABPA to stage V (fibrotic end stage). The total IgE may remain elevated in these patients, and therapy should not attempt to reduce total serum IgE to normal levels. After prolonged therapy with prednisone for asthma and control of ABPA, the IgE and IgG antibody indices against Aspergillus fumigatus may remain elevated or may be below the levels that are of diagnostic value.

In vitro activity of DJ-6783 (a keto carboxylic acid) compared with six other orally administered antimicrobial agents.

DJ-6783 is a new keto carboxylic acid having an expanded antimicrobial activity when compared with nalidixic acid or cinoxacin. Its usable activity includes the following: Enterobacteriaceae (MIC90, less than or equal to 0.06-4.0 micrograms/ml), Acinetobacter species (MIC90, 0.25-1.0 microgram/ml), Pseudomonas species (MIC90, 1.0-2.0 micrograms/ml), P. aeruginosa (MIC90, 16 micrograms/ml), Staphylococcus species (MIC90, 1.0-32 micrograms/ml), Haemophilus influenzae (MIC900, less than or equal to 0.06 microgram/ml), and Neisseria species (MIC90 less than or equal to 0.06 microgram/ml). The Streptococcus species were resistant to DL-6783 with MIC50 ranging from 16 to greater than 32 micrograms/ml. The drug appears to be bactericidal, minimally influenced by increasing inocula, but resistant mutants can be selected by serial subinhibitory concentration passages of strains in DJ-6783. The resulting resistant organisms also have higher MICs to related drugs such as norfloxacin, cinoxacin, and nalidixic acid. DJ-6783 was the most active organic acid not having structural characteristics of the fluorinated 4-quinolones.

Cefpiramide: comparative in-vitro activity and beta-lactamase stability.

Cefpiramide is a new Pseudomonas-active cephalosporin with a broad spectrum of antibacterial activity. Like cefoperazone, cefpiramide was moderately susceptible to hydrolysis by a variety of beta-lactamases from Gram-negative bacilli. Tests with 6552 bacterial isolates in five separate medical centres documented cefpiramide's effectiveness against the more commonly encountered bacterial pathogens. Additional studies with 761 selected isolates, representing 35 species, demonstrated similarities between cefpiramide and cefoperazone; cefpiramide was more active against Acinetobacter spp. and Pseudomonas spp. Like most other cephalosporins, cefpiramide inhibited methicillin-susceptible staphylococci, non-enterococcal streptococci, Neisseria gonorrhoeae, N. meningitidis and beta-lactamase-negative Haemophilus influenzae. Cefpiramide was marginally active against Streptococcus faecalis (MIC 50, 8.0 mg/l).

Allergic bronchopulmonary curvulariosis.

A patient with clinical and roentgenographic findings suggestive of allergic bronchopulmonary disease who presented with recurrent pulmonary infiltrates with peripheral eosinophilia was identified. Sputum cultures were positive for Curvularia lunata. Total serum IgE was elevated, and intracutaneous skin testing with C. lunata was positive. Serum precipitins against C. lunata were present with specific IgE and IgG antibody indexes elevated. These studies provide further Immunologic characterization of this uncommon disorder.

In vitro comparative antimicrobial activity of cefpimizole against clinical isolates from five medical centers.

Cefpimizole was compared with cefoperazone and cefotaxime against 6,599 clinical bacterial isolates from five medical centers. Cefoperazone and cefotaxime were both more active and provided a greater spectrum of antimicrobial coverage than cefpimizole. Some of the cefpimizole minimum concentrations inhibiting 50% of tested strains were as follows: Citrobacter freundii and Enterobacter cloacae, 16 micrograms/ml; Escherichia coli and Klebsiella pneumoniae, 2.0 micrograms/ml; Proteus mirabilis, 1.0 microgram/ml; Pseudomonas aeruginosa, 16 micrograms/ml; Staphylococcus spp., 32 micrograms/ml; and the enterococci, greater than 32 micrograms/ml.

Antibacterial activities of ciprofloxacin, norfloxacin, oxolinic acid, cinoxacin, and nalidixic acid.

In vitro studies were performed comparing ciprofloxacin (Bay o 9867) and norfloxacin with three related organic acids. Ciprofloxacin was two to eight times more active than norfloxacin against 658 bacterial isolates representing 30 species. For all species tested, ciprofloxacin MICs for 90% inhibition were less than or equal to 2.0 micrograms ml. Additional tests with 5,994 isolates detected only 37 (0.6%) strains resistant to 2.0 micrograms of ciprofloxacin per ml and 106 (1.8%) resistant to 1.0 micrograms/ml. Only 6 (0.1%) of the 5,994 strains were resistant to 16 micrograms of norfloxacin per ml, and 129 (2.1%) were resistant to 4.0 micrograms/ml. The majority of resistant strains were streptococci or Pseudomonas spp. Resistance among the Enterobacteriaceae was extremely rare (i.e., greater than 99.8% susceptible to both drugs.

In vitro activity of apalcillin compared with those of piperacillin and carbenicillin against 6,797 bacterial isolates from four separate medical centers.

Quantitative susceptibility tests were performed in four separate medical centers, in which apalcillin was compared with piperacillin and carbenicillin. Data from tests of 6,797 isolates confirmed that apalcillin and piperacillin had nearly identical spectra of activity but that apalcillin was significantly more active against Pseudomonas aeruginosa (MIC required to inhibit 90% of strains, 2.0 versus 64 micrograms/ml) and Acinetobacter calcoaceticus subsp. anitratus (MIC required to inhibit 90% of strains, 2.0 versus 16 micrograms/ml). Against 166 anaerobic bacterial isolates, apalcillin demonstrated in vitro activity.

Cefotetan, a new cephamycin: comparison of in vitro antimicrobial activity with other cephems, beta-lactamase stability, and preliminary recommendations for disk diffusion testing.

Cefotetan is a new, potent, 7 alpha-methoxy cephalosporin (cephamycin). The in vitro activity of cefotetan tested in a multiphasic, collaborative study against 12,260 consecutive clinical isolates and 448 selected isolates showed 93% of Enterobacteriaceae, 90% of methicillin-susceptible Staphylococcus aureus (broth dilution), 83% of Bacteroides fragilis, and 72% of non-enterococcal streptococci to be inhibited by less than or equal to 8 micrograms/ml. Beta-Lactamase-producing and -nonproducing Haemophilus influenzae strains were inhibited by less than or equal to 1.0 micrograms/ml. Cefotetan's inhibitory spectrum paralleled those of the newest generation of cephems and exceeded those of cefoxitin and cefamandole. No useful activity was present against Streptococcus faecalis or Pseudomonas aeruginosa. Cefotetan was bactericidal without significant inoculum effect and was highly resistant to hydrolysis by Richmond-Sykes types I, III, and IV beta-lactamases. Hydrolysis of the chromogenic cephalosporin PADAC (pyridine-2-azo-p-dimethylaniline cephalosporin) by type I beta-lactamases was markedly inhibited by concentrations of cefotetan similar to those of the potent inhibitor dicloxacillin. Analysis of agar disk diffusion for several disk potencies and broth dilution susceptibility tests by regression and error rate-bounding methods produced preliminary tentative zone standards (30-micrograms disk, using minimal inhibitory concentration breakpoints of less than or equal to 8 micrograms/ml susceptible and greater than 32 micrograms/ml resistant, or 75-micrograms disk, using minimal inhibitory concentration breakpoints of less than or equal to 16 micrograms/ml susceptible and greater than or equal to 64 micrograms/ml resistant) of greater than or equal to 18 mm susceptible, less than or equal to 14 mm resistant, and 15 to 17 mm indeterminate. Staphylococcus aureus testing with the 30-micrograms disk is not recommended.