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Rate coefficients for the reactions of hydroxyl radicals with a series of cyclic ethers and aliphatic diethers have been determined at 298 ± 2 K. Experiments were performed using a photolytic relative rate method at atmospheric pressure and the absolute rate technique of pulsed laser photolysis−laser induced fluorescence. The temperature dependence of the rate coefficients for the cyclic ethers was also studied over the temperature range 263−372 K. The rate coefficients show significant deviations from simple structure−activity relationships. The reactivity of the aliphatic diethers toward hydroxyl radicals is discussed in terms of the initial formation of a hydrogen-bonded adduct which then undergoes an intramolecular H atom transfer via five-, six-, and seven-membered-ring structures. The reactivity of cyclic ethers is also discussed in relation to adduct formation. However, because of steric restrictions, it is unlikely that the hydrogen-bonded adducts readily undergo H atom transfer via ring formation.

Rate constants for the reactions of OH radicals with a series of diethers and hydroxyethers have been determined at 298 ± 2 K. Rate measurements were made using a pulsed laser photolysis resonance fluorescence technique at total pressures of ~100 Torr and a conventional photolytic relative rate method at atmospheric pressure. The temperature dependencies of the rate constants for four diethers were also studied over the temperature range 230−372 K using pulsed laser photolysis resonance fluorescence. The rate data for reaction of OH with the diethers show significant deviations from simple structure−activity relationships. Evidence is presented that suggests that these deviations may be a consequence of stabilization of the reaction transition states by hydrogen bonding.

Ten cases of meningococcal meningitis in the Los Angeles County men's jail system in 1986 were the first known reported cases in this population. New cases have continued into 1990. Nineteen of 21 symptomatic cases identified by serogroup from the men's jail occurring through 1988 had serogroup C. The prevalence of meningococcal carriage and potential risk factors were studied in 1988 among 150 men booked to enter the jail, 350 inmates being released, and 100 jail staff. The prevalence of meningococcal carriage among releases, bookings, and staff were 25.4%, 18.7%, and 5.0%, respectively. Among releases, imprisonment longer than a threshold of 28 days increased carriage of serogroup C 10.0 times (95% confidence interval (CI) 4.6-21.6). Among bookings, household crowding increased serogroup C carriage 8.2 times (95% CI 1.5-45.3). Direct and passive smoking at home increased carriage of any serogroup 5.2 (95% CI 1.2-47.5) and 2.5 (95% CI 1.1-5.8) times, respectively. Feasible potential interventions include banning smoking in the jail and immunization with quadrivalent meningococcal vaccine of booked men sentenced for one month or more.

ABSTRACTIn a survey of bloodstream infection (BSI) isolates across the continental United States, 162 Candida albicansisolates were fingerprinted with the species-specific probe Ca3 and the patterns were analyzed for relatedness with a computer-assisted system. The results demonstrate that particular BSI strains are more highly concentrated in particular geographic locales and that established BSI strains are endemic in some, but not all, hospitals in the study and undergo microevolution in hospital settings. The results, however, indicate no close genetic relationship among fluconazole-resistant BSI isolates in the collection, either from the same geographic locale or the same hospital. This study represents the first of three fingerprinting studies designed to analyze the origin, genetic relatedness, and drug resistance of Candidaisolates responsible for BSI.

In 1991-92, Neisseria meningitidis group C was isolated from the blood of eight students in Urbana, Illinois, USA, and from the cerebrospinal fluid of one student from a nearby community, Decatur, Illinois. These and other bacterial species were analysed by PCR fingerprinting using primers selected from the ribosomal (r)DNA loci. A rDNA primer pairs spanning a region within the 16S rDNA amplified a predicted 280 base pair (bp) DNA fragment from Neisseria spp. and fragments of different sizes for other genera. This primer pair specifically detected a carrier of N. meningitidis in a small clinical battery. Identify of the fragment was confirmed by restriction endonuclease analysis. A 600 bp fragment was also amplified from the 16S-23S internal transcribed spacer (ITS) of N. meningitidis; amplification from six other genera yielded different-sized fragments. Digestion of the ITS fragment from N. meningitidis with Alu I revealed three patterns; pattern I was found only for serogroup C isolates, and it was the dominant pattern among recent isolates with the exception of the one from Decatur. The isolate from Decatur yielded pattern III which suggested a non-clonal relationship to the seven isolates from Urbana. Patterns II and III were more prevalent in isolates from the 1960's and 1980's. PCR-based analysis of these loci can complement the techniques which are currently used for the detection and typing of these and other eubacteria. Copyright 1993, 1999 Academic Press

Ro 2-2985 increased mean arterial blood pressure in both the venous bypass preparation and the intact animal; however, total peripheral resistance increased in the venous bypass preparation with a constant cardiac output but decreased in the intact animal with an increase in cardiac output. These observations indicate a drug-related increase in the distensibility of the aorta at the same arterial pressure. In vivo ventricular function curves were shifted to the left indicating enhanced myocardial performance with the translocation of large volumes of blood to the central circulation since total body venous compliance was significantly decreased. Beta adrenergic blocking doses of propranolol blocked the positive inotropic effect of Ro 2-2985 while myocardial depression produced by toxic doses of propranolol was reversed. This observation suggests several mechanisms for the Ro 2-2985 metabolic mediation of myocardial muscle contraction. The cardiovascular effects produced by Ro 2-2985 were accompanied by a marked polycythemia and a decrease in plasma volume without a change in total circulating blood volume, while blood glucose values showed a nonsignificant increase. Ro 2-2985 produced a marked increase in cardiac output. The increase in myocardial performance appears to be complex since myocardial force of contraction, dT/dt, dP/dt:P40 and Vmax were all increased. RO 2-2985 increased coronary flow without an increase in resistance. There were no significant increases in myocardial arteriovenous glucose, lactate, K+, Ca++, Na+ or Cl.

Over a 12-year period, 16 human strains of a gram-negative, catalase-positive, halophilic, aerobic, nonmotile, small coccoid bacterium were received for identification. On the bases of biochemical characteristics and cellular fatty acid profiles, 14 of these strains were similar to the "Philomiragia" bacterium (Yersinia philomiragia, species incertae sedis). Additional characteristics were growth on Thayer-Martin agar but no growth or sparse, delayed growth on MacConkey agar; oxidase positive; acid production, often weak and delayed, from D-glucose, sucrose, and maltose; urease negative; no reduction of nitrates; and H2S produced but often delayed in triple sugar iron agar. Both the human isolates and the "Philomiragia" bacterium contained C10:0, C14:0, C16:0, C18:1 omega 9c, C18:0, 3-OH C18:0, C22:0, and C24:1 as major cellular fatty acids and ubiquinone eight (Q8) as the major isoprenoid quinone. These cellular acids in these relative amounts have been found previously only in Francisella tularensis and Francisella novicida, suggesting a relationship between the "Philomiragia" bacterium and Francisella species. Of the 14 human "Philomiragia"-like isolates, 9 were from blood, 3 were from lung biopsies or pleural fluid, and one each was from peritoneal fluid and cerebrospinal fluid. DNA relatedness studies (hydroxyapatite method, 50 and 65 degrees C) showed that these 14 strains were a single group that was the same species as the "Philomiragia" bacterium. Two other human strains were oxidase negative and H2S negative. They formed a single DNA relatedness group that was indistinguishable from the type strains of both F. tularensis and F. novicida. DNA relatedness of "Philomiragia" bacterium type and other strains to strains of F. novicida and F. tularensis, including the type strains, was 35 to 46%. One of the two F. novicida- and F. tularensis-like strains was isolated from blood, and the other was isolated from a cervical lymph node. On the basis of these findings, we propose transferring Y. philomiragia from the genus Yersinia to the genus Francisella as Francisella philomiragia comb. nov. Having confirmed that F novicida and F. tularensis are the same species and having shown that F. novicida is pathogenic for humans, we further propose eliminating the species F. novicida and demoting it to a biogroup of F. tularensis.

A TiO2 nanocrystallite has been modified to selectively bind, by complementary hydrogen bonding, a uracil substrate incorporating a viologen moiety. Bandgap excitation of the self-assembled donor (TiO2 nanocrystallite)−acceptor (viologen) complex results in electron transfer. Some implications of these findings for the self-assembly of functional nanostructures containing both condensed phase and molecular components are considered.

TiO2 nanocrystallites are prepared by hydrolysis of titanium tetraisopropoxide in the presence of N,N‘-2,6-pyridinediylbis[undecamide]. The latter stabilizes the resulting semiconductor sol and provides sites at the surface of a nanocrystallite for selective binding of a uracil derivative by complementary hydrogen bonding. Addition of 6-(N-tridecylundecamido)methyluracil results in self-assembly of a heterosupermolecule subsequently characterized by ¹H NMR and FT-IR spectroscopies.