Periodic trends and easy estimation of relative stabilities in 11-vertex nido-p-block-heteroboranes and -borates

Density functional theory computations were carried out for 11-vertex nido-p-block-hetero(carba)boranes and -borates containing silicon, germanium, tin, arsenic, antimony, sulfur, selenium and tellurium heteroatoms. A set of quantitative values called “estimated energy penalties” was derived by comparing the energies of two reference structures that differ with respect to one structural feature only. These energy penalties behave additively, i.e., they allow us to reproduce the DFT-computed relative stabilities of 11-vertex nido-heteroboranes in general with good accuracy and to predict the thermodynamic stabilities of unknown structures easily. Energy penalties for neighboring heteroatoms (HetHet and HetHet′) decrease down the group and increase along the period (indirectly proportional to covalent radii). Energy penalties for a five- rather than four-coordinate heteroatom, [Het5k(1) and Het5k(2)], generally, increase down group 14 but decrease down group 16, while there are mixed trends for group 15 heteroatoms. The sum of HetHet′ energy penalties results in different but easily predictable open-face heteroatom positions in the thermodynamically most stable mixed heterocarbaboranes and -borates with more than two heteroatoms

Preferences for Sites of Care Among Urban Homeless and Housed Poor Adults

OBJECTIVE: To describe sources of health care used by homeless and housed poor adults. DESIGN: In a cross-sectional survey, face-to-face interviews were conducted to assess source of usual care, preferred site of care for specific problems, perceived need for health insurance at different sites of care, and satisfaction with care received. Polychotomous logistic regression analysis was used to identify the factors associated with selecting non-ambulatory-care sites for usual care. SETTING: Twenty-four community-based sites (i.e., soup kitchens, drop-in centers, and emergency shelters) frequented by the homeless and housed poor in Allegheny County, Pa. PARTICIPANTS: Of the 388 survey respondents, 85.6% were male, 78.1% African American, 76.9% between 30 and 49 years of age, 59.3% were homeless less than 1 year, and 70.6% had health insurance. MAIN RESULTS: Overall, 350 (90.2%) of the respondents were able to identify a source of usual medical care. Of those, 51.3% identified traditional ambulatory care sites (i.e., hospital-based clinics, community and VA clinics, and private physicians offices); 28.9% chose emergency departments; 8.0%, clinics based in shelters or drop-in centers; and 2.1%, other sites. Factors associated with identifying nonambulatory sites for usual care included lack of health insurance (relative risk range for all sites [RR] =3.1–4.0), homelessness for more than 2 years (RR =1.4–3.0), receiving no medical care in the previous 6 months (RR =1.6–7.5), nonveteran status (RR =1.0–2.5), being unmarried (RR =1.2–3.1), and white race (RR =1.0–3.3). CONCLUSIONS: Having no health insurance or need for care in the past 6 months increased the use of a non-ambulatory-care site as a place for usual care. Programs designed to decrease emergency department use may need to be directed at those not currently accessing any care

Arterial Blood Gas and Pulse Oximetry in Initial Management of Patients with Community-acquired Pneumonia

OBJECTIVE: To identify the factors associated with the use of arterial blood gas (ABG) and pulse oximetry (PO) in the initial management of patients with community-acquired pneumonia (CAP) and arterial hypoxemia at presentation. PARTICIPANTS: A total of 944 outpatients and 1,332 inpatients with clinical and radiographic evidence of CAP prospectively enrolled from 5 study sites in the United States and Canada. ANALYSES: Separate multivariate logistic regression analyses were used to 1) compare measurement of ABG and PO within 48 hours of presentation across sites while controlling for patient differences, and 2) identify factors associated with arterial hypoxemia (PaO(2)<60 mm Hg or SaO(2)<90% for non–African Americans and <92% for African Americans) while breathing room air. RESULTS: Range of ABG use by site was from 0% to 6.4% (P = .06) for outpatients and from 49.2% to 77.3% for inpatients (P < .001), while PO use ranged from 9.4% to 57.8% for outpatients (P < .001) and from 47.9% to 85.1% for inpatients (P < .001). Differences among sites remained after controlling for patient demographic characteristics, comorbidity, and illness severity. In patients with 1 or more measurements of oxygenation at presentation, hypoxemia was independently associated with 6 risk factors: age >30 years (odds ratio [OR], 3.2; 95% confidence interval [CI], 1.7 to 5.9), chronic obstructive pulmonary disease (OR, 1.9; 95% CI, 1.4 to 2.6), congestive heart failure (OR, 1.5; 95% CI, 1.0 to 2.1), respiratory rate >24 per minute (OR, 2.3; 95% CI, 1.8 to 3.0), altered mental status (OR, 1.6; 95% CI, 1.1 to 2.3), and chest radiographic infiltrate involving >1 lobe (OR, 2.2; 95% CI, 1.7 to 2.9). The prevalence of hypoxemia among those tested ranged from 13% for inpatients with no risk factors to 54.6% for inpatients with ≥3 risk factors. Of the 210 outpatients who had ≥2 of these risk factors, only 64 (30.5%) had either an ABG or PO performed. In the 48 outpatients tested without supplemental O(2)with ≥2 risk factors 8.3% were hypoxemic. CONCLUSIONS: In the initial management of CAP, use of ABG and PO varied widely across sites. Increasing the assessment of arterial oxygenation among patients with CAP is likely to increase the detection of arterial hypoxemia, particularly among outpatients