C-Term Faraday Rotation in Low Symmetry tert-Butyl Substituted Polyferroceniums.

Molecular thin films are currently being investigated as candidate materials to replace conventional atomistic inorganic crystal-based Faraday rotators. High symmetry paramagnetic species have been reported to exhibit large Verdet constants via magnetic field splitting of degenerate ground states. However, lower symmetry open-shell species have not been extensively studied. Herein, we report the Faraday rotation of two poly di-tert-butylferroceniums with diphenylsilane and vinylene linkers. Thin films of oxidized poly[(1,1'-di-tert-butylferrocenyl)diphenylsilane] [poly(tBu2fc-SiPh2)] displayed a 30% increase in maximum Verdet constant relative to the previously reported decamethylferrocenium/PMMA composite, with Verdet constants of -4.52 × 104 deg T-1 m-1 at 730 nm and 4.46 × 104 deg T-1 m-1 at 580 nm. When a sp2-type linker was used, as with the oxidized poly(1,1'-di-tert-butyl-ferrocenylene)vinylene [poly(tBu2fc-C═C)], negligible Faraday rotation was observed. Hence, Faraday rotation can be maintained when molecular symmetry is broken, however orbital symmetry breaking in optical transitions of interest leads to a significant loss in magneto-optical activity.

Removal of ammoniacal nitrogen from landfill leachate by irrigation onto vegetated treatment planes.

Leachate is a contaminated liquor resulting from the disposal of solid and liquid wastes at landfill sites that must be treated before discharge. Vegetated leachate treatment planes have been used at landfill sites in the UK but have received little scientific attention. This paper describes studies of model leachate treatment planes with a focus on the removal of ammoniacal nitrogen (NH3-N). Small-scale and field-scale experimental treatment planes were constructed. filled with clay loam soil and vegetated with grass (Agrostis stolonifera). Landfill leachate was applied at hydraulic loading rates ranging from 17-217l/m2/d. An exponential relationship was used to characterise the pattern of NH3-N removal. No relationship was observed between the hydraulic loading rate and the NH3-N removal rate constants (R2 = 0.0039). The daily specific NH3-N mass removal rate was found to be linearly related to the NH3-N concentration at the start of that day of treatment (R2 = 0.35). Possible causes of variation in the rate of NH3-N removal between experiments are discussed. A simple inorganic nitrogen balance indicated that the mass of N-H3-N and NO2-N removed was not accounted for by NO3-N production. Explanations for this apparent nitrogen deficit are discussed.

Bronchodilator pretreatment improves aerosol deposition uniformity in HIV-positive patients who cough while inhaling aerosolized pentamidine.

OBJECTIVE: To determine the effect of bronchodilator pretreatment on deposition uniformity of aerosolized pentamidine (AP) in HIV-positive patients who coughed while inhaling AP. DESIGN: Nonrandomized control trial. SETTING: A university hospital. PATIENTS: Ten HIV-positive patients who were using AP prophylactically. INTERVENTION: Four patients who coughed during AP administration were pretreated with 10 mg metaproterenol aerosol prior to a second inhalation of AP. MEASUREMENTS: Skew, a measure of overall deposition symmetry, deposition in the apex vs the base of the right lung (A:B ratio), and percentage of change from baseline in peak expiratory flow rate (PEFR). RESULTS: At baseline, the average (+/- SD) skew value for four subjects who coughed (0.89 +/- 0.19) was significantly higher than for six control subjects (0.58 +/- 0.07) (p < 0.01), indicating enhanced nonuniformity of AP distribution. After bronchodilator, no one coughed and the average skew value was normalized to 0.57 +/- 0.13. The A:B ratios at baseline and after metaproterenol were not significantly different, suggesting that deposition of AP in the apex, relative to basal deposition, was not enhanced by bronchodilator treatment. When no bronchodilator was administered, average PEFR decreased to 330 +/- 162 from baseline (410 +/- 84). Average PEFR increased to 429 +/- 85 from baseline (395 +/- 116) after bronchodilator pretreatment. CONCLUSIONS: These results suggest that in addition to relieving cough in patients receiving AP prophylactically, pretreatment with metaproterenol enhances uniformity of distribution of AP and improves PEFR.

A new bedside test of cognition for patients with HIV infection.

OBJECTIVE: To compare the Mental Alternation Test, a new 60-second bedside test of cognition, with the Mini-Mental State Exam (MMSE) and the Trailmaking Test, parts A and B, in patients with human immunodeficiency virus (HIV) infection. DESIGN: Cohort study. PARTICIPANTS: Sixty-two inpatients with HIV infection. SETTING: The AIDS service of a referral hospital. MEASUREMENTS: Scores on the MMSE; the Trailmaking Test, parts A and B; and the Mental Alternation Test were compared using correlation calculations and analyses of variance. Receiver operating curves were constructed to identify the best cutoff score on the Mental Alternation Test for detecting impaired performance on the MMSE and the Trailmaking Test. MAIN RESULTS: The Mental Alternation Test score correlated significantly with MMSE (r = 0.68, P < 0.01) and Trailmaking Test, part B, scores (r = -0.54, P < 0.01). The receiver operating curves showed that a Mental Alternation Test cutoff score of 15 yielded the best results for the detection of abnormal performance on the MMSE (sensitivity, 95% [95% CI, 90% to 100%]; specificity, 79% [CI, 69% to 89%]) and the Trailmaking Test, part B (sensitivity, 78% [CI, 68% to 88%]; specificity 93% [CI, 90% to 100%]). Patients making fewer than 15 alternations in 30 seconds were significantly more likely to have abnormal MMSE (P < 0.0001) and Trailmaking Test, part B, scores (P < 0.0001). The Mental Alternation Test had good reproducibility; analyses of reliability included test-retest correlation (r = 0.80) and inter-rater reliability (r = 0.85, kappa = 0.84). Time of administration was approximately 60 seconds. CONCLUSIONS: The Mental Alternation Test of cognition has good sensitivity and specificity and is easily administered. It is a valuable test to identify patients who may need further cognitive evaluation.

Ocular blood flow in dogs using radiolabelled microspheres.

We used radioactive microspheres of different sizes to determine the rate of blood flow through the various parts of the eye in dogs. The use of either 15 +/- 5 microns or 25 +/- 5 microns microspheres gave reproducible measurements of total ocular and uveal blood flows. Using these sphere sizes, retinal flow was found to be close to 1% of the total ocular blood flow and showed poor reproducibility due in part to the small number of spheres trapped in the retinal vessels.

Measurement of left ventricular ejection fraction with ionic 113mIn and a cardiac probe.

Left ventricular ejection fraction (LVEF) was measured with a cardiac probe (Nuclear Stethoscope, Bios Inc., Valhalla, New York) and 113mIn in 28 normal subjects and 86 patients with coronary artery disease (CAD). In 20 normal subjects 99mTC-RBCs were compared with 113mIn which binds to transferrin after IV injection. With 99mTc-RBCs, average LVEF was 57 +/- 7% (1 SD); with 113mIn, average LVEF was 55 +/- 8% (N.S.). Sequential measurements at different times over 60 min revealed good reproducibility. Comparison of LVEFs obtained using 99mTc-RBCs with a gamma camera and cardiac probe revealed a good correlation. The correlation coefficients were 0.92 in 25 patients with CAD and 0.95 in 10 patients with LV wall motion abnormalities. The LVEF obtained using a cardiac probe and 113mIn increased in 28 normals from 57 +/- 9% to 64 +/- 13% (P less than 0.001) during handgrip exercise, while the LVEF decreased from 45 +/- 9% to 41 +/- 10% (P less than 0.01) in patients with acute myocardial infarction 4-7 weeks after episode, from 48 +/- 11 to 40 +/- 12% (P less than 0.001) in patients with old myocardial infarction, and from 52 +/- 9 to 42 +/- 9% (P less than 0.001) in patients with angina pectoris. The cardiac probe and 113mIn provide a useful alternate means of determining left ventricular dysfunction in facilities where 99mTc and a gamma camera computer system are not readily available.

Evaluation of a miniature CdTe detector for monitoring left ventricular function.

A miniature CdTe probe interfaced to a microcomputer was used to measure left ventricular ejection fraction (LVEF) in 25 patients. LVEF obtained with the CdTe module, in the beat-to-beat mode, or the integrated gated mode agreed well with LVEF obtained with a gamma camera (r = 0.80; r = 0.82 respectively). Similarly, LVEF by CdTe probe agreed with LVEF obtained by gated equilibrium studies performed with a computerized NaI probe. The CdTe probe can provide comparable measurement of LVEF at a fraction of the cost of a camera-computer system and, being small and lightweight, the CdTe probe is adaptable for monitoring patients in intensive care facilities.