Gas-phase degradation of 2-butanethiol initiated by OH radicals and Cl atoms: kinetics,product yields and mechanism at 298 K and atmospheric pressure

Relative rate coefficients and product distribution of the reaction of 2-butanethiol (2butSH) with OH radicals and Cl atoms were obtained at atmospheric pressure and 298 K. The experiments were performed in a 480 L borosilicate glass photoreactor in synthetic air coupled to a long path “in situ” FTIR spectrometer. The rate coefficients obtained by averaging the values from different experiments were: k_OH = (2.58 ± 0.21) × 10⁻¹¹ cm³ per molecule per s and k_Cl = (2.49 ± 0.19) × 10⁻¹⁰ cm³ per molecule per s. The kinetic values were compared with related alkyl thiols and homologous alkyl alcohols, where it was found that thiols react faster with both oxidants, OH radicals and Cl atoms. SO₂ and 2-butanone were the major products identified for the reactions of 2-butanethiol with OH radicals and Cl atoms. The product yield of the reaction of 2-butanethiol and OH radicals were (81 ± 2)%, and (42 ± 1)% for SO₂ and 2-butanone, respectively. For the reactions of 2-butanethiol with Cl atom, yields of SO₂ and 2-butanone were (59 ± 2)% and (39 ± 2)%, respectively. A degradation mechanism was proposed for the pathways that leads to formation of identified products. The product distribution observed indicated that the H-atom of the S–H group abstraction channel is the main pathway for the reaction of OH radicals and Cl atoms with 2-butanethiol.

Relative rate coefficients and product distribution of the reaction of 2-butanethiol (2butSH) with OH radicals and Cl atoms were obtained at atmospheric pressure and 298 K.     

The cost of primary care research

A significant portion of research project costs is incurred before the receipt of grant funds. This poses a problem for the initiation of primary care research, especially in community practice settings. Potential investigators need financial support for staff time, training, pilot work, and grant proposal writing if primary care researchers are to compete successfully for grant funds. To find this support, we need to understand and eventually quantify the actual costs of research with attention to those that are incurred before the receipt of grant funds. We outline 10 phases of the research process and provide a model for understanding where costs are incurred and by whom. Costs include those associated with maintaining practice interest in research, supporting practice participation, and disseminating research findings. They may be incurred by either an academic center or a research network, by the practices and physicians themselves, or by an extramural funding source. The needed investment for initiating primary care research can be itemized and, with further research, quantified. This will enhance the arguments for capital investments in the primary care research enterprise.     

Relationship between prepregnancy anthrax vaccination and pregnancy and birth outcomes among US Army women

CONTEXT: Substantial concern surrounds the potential health effects of the anthrax vaccine, particularly the potential adverse effects on reproductive processes. OBJECTIVE: To determine whether receipt of anthrax vaccination by reproductive-aged women has an effect on pregnancy rates. DESIGN, SETTING, AND PATIENTS: Cohort study, based on information from a computer database, of women aged 17 to 44 years who were stationed at Fort Stewart, Ga, or Hunter Army Airfield, Ga, from January 1999 through March 2000. MAIN OUTCOME MEASURES: Pregnancy and birth rates and adverse birth outcomes. RESULTS: Of a total of 4092 women, 3136 received at least 1 dose of the anthrax vaccine. There was a total of 513 pregnancies, with 385 following at least 1 dose of anthrax vaccine. The pregnancy rate ratio (before and after adjustment for marital status, race, and age) comparing vaccinated with unvaccinated women was 0.94 (95% confidence interval [CI], 0.8-1.2; P =.60). There were 353 live births and 25 pregnancies lost to follow-up. The birth odds ratio after anthrax vaccination (before and after adjustment for marital status and age) was 0.9 (95% CI, 0.5-1.4; P =.55). After adjusting for age, the odds ratio for adverse birth outcome after receiving at least 1 dose of anthrax vaccination was 0.9 (95% CI, 0.4-2.4; P =.88). However, this study did not have sufficient power to detect adverse birth outcomes. CONCLUSION: Anthrax vaccination had no effect on pregnancy and birth rates or adverse birth outcomes.     

How many problems do family physicians manage at each encounter? A WReN study

PURPOSE: The number of problems managed concurrently by family physicians during patient encounters has not been fully explored despite the implications for quality assessment, guideline implementation, education, research, administration, and funding. Our study objective was to determine the number of problems physicians report managing at each visit and compare that with the number reflected in the chart and the bill. METHODS: Twenty-nine members of the Wisconsin Research Network reported on encounters with 572 patients using a physician problem log. The patient chart notes and the diagnoses submitted for billing from the encounters were compared with the information in these logs. RESULTS: The physicians reported managing an average of 3.05 problems per encounter and recorded 2.82 in the chart and 1.97 on the bill. For all patients, 37% of encounters addressed more than 3 problems, and 18% addressed more than 4. For patients older than 65 years, there was an average of 3.88 problems at each visit, and for diabetic patients there was an average of 4.60. There was evidence for the selective omission of mental health and substance problems from the diagnoses used for billing. CONCLUSIONS: Family medicine involves the concurrent care of multiple problems, which billing data do not adequately reflect. Our findings suggest a mismatch between family medicine and current approaches to quality assessment, guideline implementation, education, research, administration, and funding. Activities in all these areas need to address the physician's task of prioritizing and integrating care for multiple problems concurrently.     

Differential utilization and localization of ErbB receptor tyrosine kinases in skin compared to normal and malignant keratinocytes

Induction of heparin-binding epidermal growth factor-like growth factor (HB-EGF) mRNA in mouse skin organ culture was blocked by two pan-ErbB receptor tyrosine kinase (RTK) inhibitors but not by genetic ablation of ErbB1, suggesting involvement of multiple ErbB species in skin physiology. Human skin, cultured normal keratinocytes, and A431 skin carcinoma cells expressed ErbB1, ErbB2, and ErbB3, but not ErbB4. Skin and A431 cells expressed more ErbB3 than did keratinocytes. Despite strong expression of ErbB2 and ErbB3, heregulin was inactive in stimulating tyrosine phosphorylation in A431 cells. In contrast, it was highly active in MDA-MB-453 breast carcinoma cells. ErbB2 displayed punctate cytoplasmic staining in A431 and keratinocytes, compared to strong cell surface staining in MDA-MB-453. In skin, ErbB2 was cytoplasmic in basal keratinocytes, assuming a cell surface pattern in the upper suprabasal layers. In contrast, ErbB1 retained a cell surface distribution in all epidermal layers. Keratinocyte proliferation in culture was found to be ErbB1-RTK-dependent, using a selective inhibitor. These results suggest that in skin keratinocytes, ErbB2 transduces ligand-dependent differentiation signals, whereas ErbB1 transduces ligand-dependent proliferation/survival signals. Intracellular sequestration of ErbB2 may contribute to the malignant phenotype of A431 cells, by allowing them to respond to ErbB1-dependent growth/survival signals, while evading ErbB2-dependent differentiation signals.     

Urolithiasis in pediatric patients: a single center study of incidence, clinical presentation and outcome

PURPOSE: The incidence of kidney stones in adults has increased in the last 30 years. This retrospective, single site review was done to test the hypotheses that the incidence of urolithiasis in pediatric patients increased from 1994 to 2005, and that metabolic abnormalities were more common in patients with renal stones in the final 3 years of the study period. MATERIALS AND METHODS: Charts from 2 time periods were reviewed, 1994 to 1996 (period 1) and 2003 to 2005 (period 2). Clinical and laboratory data, including demographics, presenting complaints, laboratory assessment, treatment and outcome, were tabulated in patients with confirmed urolithiasis. RESULTS: The number of patients with urolithiasis increased from 7 in period 1 to 61 in period 2. When expressed as cases per 100 new patients the incidence increased 4.6 times (p = 0.014). Focusing on period 2, 28% of patients were younger than 10 years. While blood tests were generally normal, 76% of patients had at least 1 abnormality in the 24-hour urine collection. Hypocitraturia, which was the most common metabolic abnormality, was noted in 52% of patients. The small number of patients in period 1 precluded determination as to whether metabolic abnormalities were more common in period 2. Surgery and/or lithotripsy was required in 12 children. Stone disease recurred in 39% of the patients. CONCLUSIONS: The incidence of urolithiasis in the pediatric population increased nearly 5-fold at our institution during the last decade. We recommend that the primary diagnostic test be a 24-hour urine collection. The most common metabolic abnormality was hypocitraturia, followed by hypercalciuria. Recurrence of stones is common (approximately 40% rate) and followup is advised.