The mechanism of C–H oxidation of propylene (C3H6) and 1-phenyl-1-pentyne (C3H7–CC–Ph) by HOOR (RMe, t Bu) and 3O2 by a copper–salen complex was explored by computations. The most noteworthy step ...is the complexation of two Cu salens to the peroxide to form either the LCuOH/LCuOR pair or an OH-bridged complex LCu(μ-OH)CuL plus OR. The latter pathway involves an avoided crossing of two triplet electronic states. The LCuOH complex can abstract a hydrogen atom from C3H6 and the C3H5 radical plus 3O2 forms the complex LCuOOC3H5. Migration of a hydrogen to the proximal oxygen atom reforms LCuOH and acrolein HC(O)CHCH2.
Geometries and electronic properties of neutral Agn, cationic Agn+, and anionic Agn- silver clusters with n = 2-22 were investigated by density functional theory (DFT) with M06 functional. For ...neutral clusters, transition from planar to "empty cage" structure occurs at n = 7, "empty cage" to "cage with one Ag atom" at n = 18, and to "cage with two Ag atoms" at n = 22. For lowest-energy Agn clusters, Ag8 and Ag18 show lowest polarizability due to closed-shell valence electron configurations 1S2/1P6 and 1S2/1P6/1D10. High stability of Ag8 is manifested in small dissociation energies of Ag9 to Ag8 plus Ag1 and Ag10 cluster to Ag8 plus Ag2. Cluster Ag20 with configuration 1S2/1P6/1D10/2S2 is stable due to low dissociation energy of Ag21 to Ag1 and Ag22 to Ag2. Cationic clusters with even n namely Ag10+ (9 valence electrons), Ag16+ (15 valence electrons), and Ag22+ (21 valence electrons) dissociate to Ag1 and closed-shell Ag9+ (1S2/1P6), Ag15+ (1S2/1D10/2S2) and Ag21+ (1S2/1P6/1D10/2S2). For odd n, Ag11+ and Ag17+ dissociate to Ag2 and closed-shell Ag9+ and Ag15+. For anionic clusters Agn-, cohesion energy Ecoh and binding energy (BE) show maxima at n = 7 and n = 17 due to stable Ag7- and Ag17- clusters. Small Agn- clusters (n = 4-11) with even n (except n = 8) have lower dissociation energy for loss of Ag1 while those with odd n have lower dissociation energy for loss of Ag2. For n = 12-22, all clusters have lower dissociation energy for loss of Ag1.
OBJECTIVE
To examine the association between hearing aids (HAs) and time to diagnosis of Alzheimer disease (AD) or dementia, anxiety or depression, and injurious falls among adults, aged 66 years and ...older, within 3 years of hearing loss (HL) diagnosis.
DESIGN
Retrospective cohort study.
SETTING
We used 2008 to 2016 national longitudinal claims data (based on office visit, inpatient, or outpatient healthcare encounters) from a large private payer. We used Kaplan‐Meier curves to examine unadjusted disease‐free survival and crude and adjusted Cox regression models to examine associations between HAs and time to diagnosis of three age‐related/HL‐associated conditions within 3 years of HL diagnosis. All models were adjusted for age, sex, race/ethnicity, census divisions, and prior diagnosis of cardiovascular conditions, hypertension, hypercholesterolemia, obesity, and diabetes.
PARTICIPANTS
The participants included 114 862 adults, aged 66 years and older, diagnosed with HL.
MEASUREMENT
Diagnosis of (1) AD or dementia; (2) depression or anxiety; and (3) injurious falls.
INTERVENTION
Use of HAs.
RESULTS
Large sex and racial/ethnic differences exist in HA use. Approximately 11.3% of women vs 13.3% of men used HAs (95% confidence interval CI difference = −0.024 to −0.016). Approximately 13.6% of whites (95% CI = 0.13‐0.14) vs 9.8% of blacks (95% CI = 0.09‐0.11) and 6.5% of Hispanics (95% CI = 0.06‐0.07) used HAs. The risk‐adjusted hazard ratios of being diagnosed with AD/dementia, anxiety/depression, and injurious falls within 3 years after HL diagnosis, for those who used HAs vs those who did not, were 0.82 (95% CI = 0.76‐0.89), 0.89 (95% CI = 0.86‐0.93), and 0.87 (95% CI = 0.80‐0.95), respectively.
CONCLUSIONS
Use of HAs is associated with delayed diagnosis of AD, dementia, depression, anxiety, and injurious falls among older adults with HL. Although we have shown an association between use of HAs and reduced risk of physical and mental decline, randomized trials are needed to determine whether, and to what extent, the relationship is causal. J Am Geriatr Soc 67:2362–2369, 2019
A truncated model of the FeMo cofactor is used to explore a new mechanism for the conversion of N2 to NH3 by the nitrogenase enzyme. After four initial protonation/reduction steps, the H4CFe8S9 ...cluster has two hydrogen atoms attached to sulfur, one hydrogen bridging two iron centers and one hydrogen bonded to carbon. The loss of the CH and FeHFe hydrogens as molecular hydrogen activates the cluster to addition of N2 to the carbon center. This unique step takes place at a nearly planar four-coordinate carbon center and leads to an intermediate with a significantly weakened N–N bond. A hydrogen attached to a sulfur atom is then transferred to the distal nitrogen atom. Additional prontonation/reduction steps are modeled by adding a hydrogen atom to sulfur and locating the transition states for transfer to nitrogen. The first NH3 is lost in a thermal neutral step, while the second step is endothermic. The loss of H2 activates the complex by reducing the barrier for N2 addition by 3.5 kcal/mol. Since this is the most difficult step in the mechanism, reducing the barrier for this step justifies the “extra expense” of H2 production.
An essential issue for laboratory experiments to inform policy debates is the “external validity” of the experimental results; that is, does behavior in the laboratory apply to behavior that occurs ...in the naturally occurring world? We examine this issue of external validity in the specific context of laboratory experiments on tax compliance, using two different types of evidence. We find that the behavioral patterns of subjects in the laboratory conform to those of individuals making a similar decision in naturally occurring settings. We also find that the behavioral responses of students are largely the same as those of nonstudents in identical experiments (JEL C9, H0, H3)
Flail chest injuries are associated with severe pulmonary restriction, a requirement for intubation and mechanical ventilation, and high rates of morbidity and mortality. Our goals were to ...investigate the prevalence, current treatment practices, and outcomes of flail chest injuries in polytrauma patients.
The National Trauma Data Bank was used for a retrospective analysis of the injury patterns, management, and clinical outcomes associated with flail chest injuries. Patients with a flail chest injury admitted from 2007 to 2009 were included in the analysis. Outcomes included the number of days on mechanical ventilation, days in the intensive care unit (ICU), days in the hospital, and rates of pneumonia, sepsis, tracheostomy, chest tube placement, and death.
Flail chest injury was identified in 3,467 patients; the mean age was 52.5 years, and 77% of the patients were male. Significant head injury was present in 15%, while 54% had lung contusions. Treatment practices included epidural catheters in 8% and surgical fixation of the chest wall in 0.7% of the patients. Mechanical ventilation was required in 59%, for a mean of 12.1 days. ICU admission was required in 82%, for a mean of 11.7 days. Chest tubes were used in 44%, and 21% required a tracheostomy. Complications included pneumonia in 21%, adult respiratory distress syndrome in 14%, sepsis in 7%, and death in 16%. Patients with concurrent severe head injury had higher rates of ventilatory support and ICU stay and had worse outcomes in every category compared with those without a head injury.
Patients who have sustained a flail chest have significant morbidity and mortality. More than 99% of these patients were treated nonoperatively, and only a small proportion (8%) received aggressive pain management with epidural catheters. Given the high rates of morbidity and mortality in patients with a flail chest injury, alternate methods of treatment including more consistent use of epidural catheters for pain or surgical fixation need to be investigated with large randomized controlled trials.
Epidemiologic/prognostic study, level IV.
Theoretical Study of Methane Storage in Cu24(m‑BDC)24 McKee, Michael L
The journal of physical chemistry. A, Molecules, spectroscopy, kinetics, environment, & general theory,
07/2019, Letnik:
123, Številka:
29
Journal Article
Recenzirano
Calculations on the Cu24(m-BDC)24 (m-BDC = 1,3-benzenedicarboxylate) polyoxometalate (POM) cage with 0, 12, 24, and 40 methane molecules inside were made using the M06 exchange/correlation ...functional. During filling of the cage with 40 CH4 molecules, the 12 strongest binding CH4 molecules are those to the coordination unsaturated sites (CUS) to the inwardly directed Cu(+2) centers via agostic interactions. The next 12 CH4 molecules are less tightly bound followed by the next 16 CH4 molecules with average binding energies of 8.27, 7.88, and 7.36 kcal/mol per CH4, respectively. A section of the Cu24(m-BDC)24 cage was taken with the formula Cu4(m-BDC)(BC)6 (BC = benezenecarboxylate) in order to estimate zero-point, thermal, and entropy corrections of the larger cage. Estimating free energies at 1 bar, the Cu24(m-BDC)24 POM is predicted to lose 16, 12, and 12 CH4 molecules at 67, 123, and 171 °C, respectively. The 40CH4@Cu24(m-BDC)24 cage, which is isostructural to the main cavity of HKUST-1 with 40 CH4 molecules inside, is predicted to have a loading of 224 cm3(STP) cm–3 at 1 bar.
Hearing loss is increasingly prevalent among younger adults, impacting health and health care use. Deaf and hard of hearing (DHH) women have a higher risk of chronic diseases, pregnancy ...complications, and adverse birth outcomes compared with hearing women. Health care utilization patterns during the perinatal period remain not well understood. The objective of this study was to examine differences in antenatal emergency department and inpatient utilization among DHH and non-DHH women.
We conducted a retrospective cohort study design to analyze 2002 to 2013 Massachusetts Pregnancy to Early Life Longitudinal data to compare antenatal inpatient and emergency department use between DHH (
= 925) and hearing (
= 2,895) women with singleton deliveries. Matching was done based on delivery year, age at delivery, and birth parity in 1:3 case-control ratio. Demographic, socioeconomic, clinical, and hospital characteristics were first compared for DHH mothers and the matched control group using chi-squared tests and
-tests. Multivariable models were adjusted for sociodemographic and clinical characteristics.
Among DHH women (
= 925), 49% had at least one emergency department visit, 19% had an observational stay, and 14% had a nondelivery hospital stay compared with 26, 14, and 6%, respectively, among hearing women (
= 28,95) during the antenatal period (all
s < 0.001). The risk of nondelivery emergency department visits (risk ratio RR 1.58;
< 0.001) and inpatient stays (RR = 1.89;
< 0.001) remained higher among DHH women compared with hearing women even after adjustment. Having four or more antenatal emergency department visits (7 vs. 2%) and two or more nondelivery hospital stays (4 vs. 0.4%) were more common among pregnant DHH women compared with their controls (all
-values < 0.001).
The findings demonstrate that DHH women use emergency departments and inpatient services at a significantly higher rate than their hearing controls during the antenatal period. A systematic investigation of the mechanisms for these findings are needed.
· Antenatal emergency department use is significantly higher among deaf and hard of hearing women.. · Antenatal hospitalizations are significantly higher among deaf and hard of hearing women.. · Hearing loss screening may identify those at risk for adverse pregnancy and birth outcomes..
Prior studies on severe maternal morbidity (SMM) have often excluded women who are deaf or hard of hearing (DHH), even though they are at increased risk of pregnancy complications and adverse birth ...outcomes. This study compared rates of SMM during delivery and postpartum among DHH and non-DHH women.
This nationally representative retrospective cohort study used hospital discharge data from the 2004–2020 Health Care and Cost Utilization Project Nationwide Inpatient Sample. The risk of SMM with and without blood transfusion during delivery and postpartum among DHH and non-DHH women were compared using modified Poisson regression analysis. The study was conducted in the United States in 2022–2023.
The cohort included 9351 births to DHH women for the study period, and 13,574,382 age-matched and delivery year-matched births to non-DHH women in a 1:3 case-control ratio. The main outcomes were SMM and non-transfusion SMM during delivery and postpartum. Relative risks were sequentially adjusted for sociodemographic characteristics, hospital-level characteristics, and clinical characteristics. In unadjusted analyses, DHH women were at 80% higher risk for SMM (RR = 1.81, 95% CI 1.63–2.02, p < 0.001) during delivery and postpartum compared to non-DHH women. Adjustment for socio-demographic and hospital characteristics attenuated risk for SMM (RR = 1.54, 95% CI 1.38–1.72, p < 0.001). Adjustment for the Elixhauser comorbidity score further attenuated the risk of SMM among DHH women (RR = 1.13, 95% CI 1.01–1.26, p < 0.05).
The findings of this study demonstrate a critical need for inclusive preconception, prenatal, and postpartum care that address conditions that increase the risk for SMM among DHH people.
•This study examined rates of SMM among DHH women compared to non-DHH women.•DHH women had ∼80% higher risk for SMM than non-DHH women (unadjusted).•Inclusive care should address conditions that increase DHH people's risk of SMM.
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