Photoelectron Circular Dichroism in the Spin-Polarized Spectra of Chiral Molecules

We studied strong-field multiphoton ionization of 1-iodo-2-methylbutane enantiomers with 395 nm circularly polarized laser pulses experimentally and theoretically. For randomly oriented molecules, we observe spin polarization up to about 15%, which is independent of the molecular enantiomer. Our experimental findings are explained theoretically as an intricate interplay between three contributions from HOMO, HOMO-1, and HOMO-2, which are formed of 5p-electrons of the iodine atom. For uniaxially oriented molecules, our theory demonstrates even larger spin polarization. Moreover, we predict a sizable enantiosensitive photoelectron circular dichroism of about 10%, which is different for different spin states of photoelectrons.

Outcomes across the tuberculosis care continuum among adolescents in Haiti

Setting: GHESKIO (Groupe Haitien d'Etude du Sarcome de Kaposi et des Infections Opportunistes) clinic, Port-au-Prince, Haiti. Objective: To evaluate tuberculosis (TB) care continuum outcomes among adolescents. Design: Among a retrospective cohort of 10-24 year olds diagnosed with active TB, we report completion of the following steps of the TB care continuum stratified by human immunodeficiency virus (HIV) status: diagnosis of microbiologically confirmed TB, initiation of anti-tuberculosis treatment, retention in care at 2 months on anti-tuberculosis treatment, and TB treatment success. Factors associated with attrition at each step were identified using multivariable regression. Results: A total of 1005 adolescents were diagnosed with active TB; 74 (7%) were HIV-positive at the time of TB diagnosis. HIV-positive patients had poorer outcomes than non-HIV-infected patients: 73% vs. 85% initiated anti-tuberculosis treatment (P < 0.01), 46% vs. 74% were retained in care at 2 months (P < 0.01), and 41% vs. 68% achieved TB treatment success (P < 0.01). Among those who initiated treatment, same-day initiation resulted in less treatment failure. Attrition before treatment initiation was associated with female sex and HIV coinfection. Attrition after treatment initiation was associated with age ⩾16 years and HIV coinfection. Conclusion: Outcomes across the TB care continuum are suboptimal among adolescents, with only two thirds of patients achieving treatment success. Interventions tailored to adolescents are needed to improve retention in care, particularly for those who are co-infected with HIV.

Evaluation of antibiotic susceptibility testing by agar dilution and the Micro Media system (Fox Panel)

The susceptibilities of 350 gram-positive cocci and 638 gram-negative bacilli to various antimicrobial agents were compared by using the Micro-Media system (MMS) (Fox Panel) (Micro-Media Systems, Inc., Potomac, Md.) and a standard agar dilution procedure. Major discrepancies occurred with enterococci, among which 48 of 53 isolates (91%) were found to be resistant to penicillin G by agar dilution and reported as susceptible by the MMS. Other large discrepancies occurred with Staphylococcus aureus and Acinetobacter calcoaceticus subsp. anitratus, among which more than 40% of the isolates were judged to be resistant to ampicillin by agar dilution and susceptible by the MMS. In terms of overall agreement in interpretation of MICs by the two systems, an agreement of greater than 84% was seen for both gram-positive and gram-negative organisms when ampicillin and cephalothin (68 and 78% agreement for gram-positive cocci, respectively) were excluded. These disagreements in MIC interpretations may result in part from the small number of organisms tested per well (4,000 CFU) in the MMS, as compared with 10,000 CFU per test in the agar dilution method.

Oxolinic acid in the treatment of typhoid fever due to chloramphenicol-resistant strains of Salmonella typhi

Of 28 strains of Salmonella typhosa collected in late 1972 in Vietnam, 4 had minimum inhibitory concentrations to chloramphenicol of >100 mug/ml. Median minimum inhibitory concentrations of all strains to oxolinic acid were 0.39 mug/ml; ampicillin, 6.25 mug/ml; amoxicillin, 0.39 mug/ml. Widespread typhoid fever appeared in mid-1973 with more than three-fourths of strains found to be resistant to chloramphenicol. Peak serum concentrations of oxolinic acid average 3.0 mug/ml after the oral ingestion of 1.0 g. In July 1974, a pilot study was begun to evaluate the efficacy of oxolinic acid in vivo, recognizing the discrepancy between in vitro and in vivo results with many agents evaluated in the treatment of typhoid fever. Seven patients with typhoid fever, six with positive blood cultures, were treated with oxolinic acid (1.5 g twice daily by mouth, a daily dose that averaged 75 mg/kg per day) for 5 to 12 days. In four of six patients, blood cultures became negative at 2 to 3 days, with another being negative at 6 days. Despite negative blood cultures, all but one patient remained clinically ill with temperatures of >39.5 C at 4 to 9 days. All strains were susceptible to 0.19 mug of oxolinic acid per ml, and resistant strains did not occur. One patient died after being changed to ampicillin, one left against advice, three responded to amoxicillin, and one died with pseudomonas bacteremia. Toxicity to oxolinic acid did not occur.