Stability and Reversibility of Lithium Borohydrides Doped by Metal Halides and Hydrides

In an effort to develop reversible metal borohydrides with high hydrogen storage capacities and low dehydriding temperature, doping LiBH4 with various metal halides and hydrides has been conducted. Several metal halides such as TiCl3, TiF3, and ZnF2 effectively reduced the dehydriding temperature through a cation exchange interaction. Some of the halide doped LiBH4 are partially reversible. The LiBH4 + 0.1TiF3 desorbed 3.5 wt % and 8.5 wt % hydrogen at 150 and 450 °C, respectively, with subsequent reabsorption of 6 wt % hydrogen at 500 °C and 70 bar observed. XRD and NMR analysis of the rehydrided samples confirmed the reformation of LiBH4. The existence of the (B12H12)−2 species in dehydrided and rehydrided samples gives insight into the resultant partial reversibility. A number of other halides, MgF2, MgCl2, CaCl2, SrCl2, and FeCl3, did not reduce the dehydriding temperature of LiBH4 significantly. XRD and TGA-RGA analyses indicated that an increasing proportion of halides such as TiCl3, TiF3, and ZnCl2 from 0.1 to 0.5 mol makes lithium borohydrides less stable and volatile. Although the less stable borohydrides such as LiBH4 + 0.5TiCl3, LiBH4 + 0.5TiF3, and LiBH4 + 0.5ZnCl2 release hydrogen at room temperature, they are not reversible due to unrecoverable boron loss caused by diborane emission. In most cases, doping that produced less stable borohydrides also reduced the reversible hydrogen uptake. It was also observed that halide doping changed the melting points and reduced air sensitivity of lithium borohydrides

Survival after hospital discharge for ST-segment elevation and non-ST-segment elevation acute myocardial infarction: a population-based study

BACKGROUND: Limited recent data are available describing differences in long-term survival, and factors affecting prognosis, after ST-segment elevation myocardial infarction (STEMI) and non-ST-segment elevation myocardial infarction (NSTEMI), especially from the more generalizable perspective of a population-based investigation. The objectives of this study were to examine differences in post-discharge prognosis after hospitalization for STEMI and NSTEMI, with a particular focus on factors associated with reduced long-term survival. METHODS: We reviewed the medical records of residents of the Worcester, MA, USA metropolitan area hospitalized at eleven central Massachusetts medical centers for acute myocardial infarction (AMI) during 2001, 2003, 2005, and 2007. RESULTS: A total of 3762 persons were hospitalized with confirmed AMI; of these, 2539 patients (67.5%) were diagnosed with NSTEMI. The average age of study patients was 70.3 years and 42.9% were women. Patients with NSTEMI experienced higher post-discharge death rates with 3-month, 1-year, and 2-year death rates of 12.6%, 23.5%, and 33.2%, respectively, compared to 6.1%, 11.5%, and 16.4% for patients with STEMI. After multivariable adjustment, patients with NSTEMI were significantly more likely to have died after hospital discharge (adjusted hazards ratio 1.28; 95% confidence interval 1.14-1.44). Several demographic (eg, older age) and clinical (eg, history of stroke) factors were associated with reduced long-term survival in patients with NSTEMI and STEMI. CONCLUSIONS: The results of this study in residents of central Massachusetts suggest that patients with NSTEMI are at higher risk for dying after hospital discharge, and several subgroups are at particularly increased risk

Trends in the medical management of patients with heart failure

BACKGROUND: Despite the availability of effective therapies, heart failure (HF) remains a highly prevalent disease and the leading cause of hospitalizations in the U.S. Few data are available, however, describing changing trends in the use of various cardiac medications to treat patients with HF and factors associated with treatment. The objectives of this population-based study were to examine decade-long trends (1995 - 2004) in the use of several cardiac medications in patients hospitalized with acute decompensated heart failure (ADHF) and factors associated with evidence-based treatment. METHODS: We reviewed the medical records of 9,748 residents of the Worcester, MA, metropolitan area who were hospitalized with ADHF at all 11 central Massachusetts medical centers in 1995, 2000, 2002, and 2004. RESULTS: Between 1995 and 2004, respectively, the prescription upon hospital discharge of beta-blockers (23%; 67%), angiotensin pathway inhibitors (47%; 55%), statins (5%; 43%), and aspirin (35%; 51%) increased markedly, while the use of digoxin (51%; 29%), nitrates (46%; 24%), and calcium channel blockers (33%; 22%) declined significantly; nearly all patients received diuretics. Patients in the earliest study year, those with a history of obstructive pulmonary disease or anemia, incident HF, non-specific symptoms, and women were less likely to receive beta blockers and angiotensin pathway inhibitors than respective comparison groups. In 2004, 82% of patients were discharged on at least one of these recommended agents; however, only 41% were discharged on medications from both recommended classes. CONCLUSIONS: Our data suggest that opportunities exist to further improve the use of HF therapeutics

Six-month mortality rates are lower in patients with an acute coronary syndrome treated with the combination of clopidogrel and a statin than in patients treated with either therapy alone: An analysis from the global registry of acute coronary events

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Cognitive impairment and self-care in heart failure

BACKGROUND: Heart failure (HF) is a prevalent chronic disease in older adults that requires extensive self-care to prevent decompensation and hospitalization. Cognitive impairment may impact the ability to perform HF self-care activities. We examined the association between cognitive impairment and adherence to self-care in patients hospitalized for acute HF. DESIGN: Prospective cohort study. SETTING AND PARTICIPANTS: A total of 577 patients (mean age = 71 years, 44% female) hospitalized for HF at five medical centers in the United States and Canada. MEASUREMENTS AND METHODS: Participants were interviewed for information on self-reported adherence to self-care using the European Heart Failure Self-care Behaviour Scale. We assessed cognitive impairment in three domains (memory, processing speed, and executive function) using standardized measures. Patients\u27 demographic and clinical characteristics were obtained through medical record review. Multivariable linear regression was used to examine the association between cognitive impairment and self-care practices adjusting for demographic and clinical factors. RESULTS: A total of 453 patients (79%) were impaired in at least one cognitive domain. Average adherence to self-care activities among patients with global cognitive impairment did not differ significantly from those without cognitive impairment (30.5 versus 29.6; 45-point scale). However, impaired memory was associated with lower self-care scores (P = 0.006) in multivariable models. CONCLUSION: Cognitive impairment is highly prevalent among older patients hospitalized for HF. Memory impairment is associated with poorer adherence to self-care practices. Screening for memory impairment in patients with HF may help to identify patients at risk for poor self-care who may benefit from tailored disease management programs

Management of Platelet-Directed Pharmacotherapy in Patients With Atherosclerotic Coronary Artery Disease Undergoing Elective Endoscopic Gastrointestinal Procedures

The periprocedural management of patients with atherosclerotic coronary heart disease, including those who have heart disease and those who are undergoing percutaneous coronary intervention and stent placement who might require temporary interruption of platelet-directed pharmacotherapy for the purpose of an elective endoscopic gastrointestinal procedure, is a common clinical scenario in daily practice. Herein, we summarize the available information that can be employed for making management decisions and provide general guidance for risk assessment

Hospitalization for Hemorrhage Among Warfarin Recipients Prescribed Amiodarone

Amiodarone inhibits the hepatic metabolism of warfarin, potentiating its anticoagulant effect. However, the clinical consequences of this are not well established. Our objective in this study was to characterize the risk of hospitalization for a hemorrhage associated with the initiation of amiodarone within a cohort of continuous warfarin users in Ontario. We conducted a population-based retrospective cohort study among Ontario residents aged ≥66 years receiving warfarin. Among patients with at least 6 months of continuous warfarin therapy, we identified those who were newly prescribed amiodarone and an equal number who were not, matching on age, gender, year of cohort entry, and a high-dimensional propensity score. The primary outcome was hospitalization for hemorrhage within 30 days of amiodarone initiation. Between July 1, 1994, and March 31, 2009, we identified 60,497 patients with at least 6 months of continuous warfarin therapy, of whom 11,665 (19%) commenced amiodarone. For 7,124 (61%) of these, we identified a matched control subject who did not receive amiodarone. Overall, 56 (0.8%) amiodarone recipients and 23 (0.3%) control patients were hospitalized for hemorrhage within 30 days of initiating amiodarone (adjusted hazard ratio 2.45; 95% confidence interval, 1.49–4.02). Seven of 56 (12.5%) patients hospitalized for a hemorrhage after starting amiodarone died in hospital. In conclusion, initiation of amiodarone among older patients receiving warfarin is associated with a more than twofold increase in the risk of hospitalization for hemorrhage, with a relatively high fatality rate. Physicians should closely monitor patients who initiate amiodarone while receiving warfarin