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Sample records for acute decompensated hf

  1. Acute Decompensated Heart Failure

    PubMed Central

    Joseph, Susan M.; Cedars, Ari M.; Ewald, Gregory A.; Geltman, Edward M.; Mann, Douglas L.

    2009-01-01

    Hospitalizations for acute decompensated heart failure are increasing in the United States. Moreover, the prevalence of heart failure is increasing consequent to an increased number of older individuals, as well as to improvement in therapies for coronary artery disease and sudden cardiac death that have enabled patients to live longer with cardiovascular disease. The main treatment goals in the hospitalized patient with heart failure are to restore euvolemia and to minimize adverse events. Common in-hospital treatments include intravenous diuretics, vasodilators, and inotropic agents. Novel pharmaceutical agents have shown promise in the treatment of acute decompensated heart failure and may simplify the treatment and reduce the morbidity associated with the disease. This review summarizes the contemporary management of patients with acute decompensated heart failure. PMID:20069075

  2. Hospital Management of Acute Decompensated Heart Failure.

    PubMed

    Abdo, Ashraf S

    2017-03-01

    Heart failure (HF) is one of the leading causes of hospitalizations for elderly adults in the United States. One in 5 Americans will be >65 years of age by 2050. Because of the high prevalence of HF in this group, the number of Americans requiring hospitalization for this disorder is expected to rise significantly. We reviewed the most recent and ongoing studies and recommendations for the management of patients hospitalized due to decompensated HF. The Acute Decompensated Heart Failure National Registry, together with the 2013 American College of Cardiology Foundation and American Heart Association heart failure guidelines, earlier retrospective and prospective studies including the Diuretic Optimization Strategies Evaluation (DOSE), the Trial of Intensified vs Standard Medical Therapy in the Elderly Patients With Congestive Heart Failure (TIME-CHF), the Organized Program to Initiate Lifesaving Treatment in Hospitalized Patients with Heart Failure (OPTIMIZE-HF), the Rapid Emergency Department Heart Failure Outpatient Trial (REDHOT) and the Comparison of Medical, Pacing and Defibrillation Therapies in Heart Failure (COMPANION) trial were reviewed for current practices pertaining to these patients. Gaps in our knowledge of optimal use of patient-specific information (biomarkers and comorbid conditions) still exist.

  3. [Therapeutic strategies in acute decompensated heart failure and cardiogenic shock].

    PubMed

    Buerke, M; Lemm, H; Russ, M; Schlitt, A; Werdan, K

    2010-08-01

    As the population of elderly people is increasing, the number of patients requiring hospitalization for acute exacerbations is rising. Traditionally, these episodes of hemodynamic instability were viewed as a transient event characterized by systolic dysfunction, low cardiac output, and fluid overload. Diuretics, along with vasodilator and inotropic therapy, eventually became elements of standard care. In a multicenter observational registry (ADHERE--Acute Decompensated Heart Failure National Registry) of more than 275 hospitals, patients with acute decompensated heart failure were analyzed for their characteristics and treatments options. These data have shown that this population consists of multiple types of heart failure, various forms of acute decompensation, combinations of comorbidities, and varying degrees of disease severity. The challenges in the treatment require multidisciplinary approaches since patients typically are elderly and have complex combinations of comorbidities. So far only a limited number of drugs is currently available to treat the different groups. Over the past years it was shown that even "standard drugs" might be deleterious by induction of myocardial injury, worsening of renal function or increasing mortality upon treatment. Therefore, based on pathophysiology, different types of acute decompensated heart failure require specialized treatment strategies.

  4. The Change in Body Weight During Hospitalization Predicts Mortality in Patients With Acute Decompensated Heart Failure

    PubMed Central

    Komaki, Tomo; Miura, Shin-ichiro; Arimura, Tadaaki; Shiga, Yuhei; Morii, Joji; Kuwano, Takashi; Imaizumi, Satoshi; Kitajima, Ken; Iwata, Atsushi; Morito, Natsumi; Yahiro, Eiji; Fujimi, Kanta; Matsunaga, Akira; Saku, Keijiro

    2017-01-01

    Background In our experience, the change in body weight (BW) during hospitalization varies greatly in patients with acute decompensated heart failure (HF). Since the clinical significance of a change in BW is not clear, we investigated whether a change in BW could predict mortality. Methods We retrospectively enrolled 130 patients (72 males; aged 68 ± 10 years) who were hospitalized due to acute decompensated HF and followed for 2 years after discharge. The change in the BW index during hospitalization (ΔBWI) was calculated as (BW at hospital admission minus BW at hospital discharge)/body surface area at hospital discharge. Results The patients were divided into quartiles according to ΔBWI, and the 2-year mortality rates in the quartiles with the lowest, second, third and highest ΔBWI were 18.8%, 12.1%, 3.1% and 9.1%, respectively. In a multivariate Cox proportional hazards analysis after adjusting for variables with a P value less than 0.05, ΔBWI was independently associated with 2-year mortality (P = 0.0002), and the quartile with the lowest ΔBWI had a higher relative risk (RR) for 2-year mortality than the quartile with the highest ΔBWI (RR: 7.46, 95% confidence interval: 1.03 - 53.99, P = 0.04). Conclusion In conclusion, ΔBWI was significantly associated with 2-year mortality after discharge, which indicates that ΔBWI might be a simple predictor of prognosis in acute decompensated HF. PMID:28179967

  5. Long-Term Survival for Patients with Acute Decompensated Heart Failure According to Ejection Fraction Findings

    PubMed Central

    Coles, Andrew H.; Fisher, Kimberly; Darling, Chad; Yarzebski, Jorge; McManus, David D.; Gore, Joel M.; Lessard, Darleen; Goldberg, Robert J.

    2014-01-01

    Limited data exists about the long-term prognosis of patients with acute decompensated heart failure (ADHF) further stratified according to ejection fraction (EF) findings. The primary objective of this population-based observational study was to characterize and compare trends in long-term prognosis after an episode of ADHF across 3 EF strata. Hospital medical records were reviewed for 3,604 residents of the Worcester (MA) metropolitan area who were discharged after ADHF from all 11 medical centers in central Massachusetts during 1995, 2000, 2002, and 2004 and had EF measurements during their index hospitalization. The average age of this population was 75 years, the majority was white, and 44% were men. Approximately 49% of the population had preserved EF HF (HF-PEF) (≥50%), 37% had reduced EF HF (HF-REF) (<40%), and 14% had borderline EF HF (41-49%) (HF-BREF). Patients with HF-PEF experienced higher post discharge survival rates than patients with either HF-REF or HF-BREF at 1, 2, and 5-years after discharge from all central Massachusetts medical centers. While prognosis at 1-year after hospital discharge improved for all patient groups during the years under study, especially for those with HF-REF and HF-PEF, these encouraging trends declined with increasing duration of follow-up. In conclusion, although improvements in 1-year post-discharge survival were observed for patients in each of the 3 EF groups examined to varying degrees, the post-discharge prognosis of all patients with ADHF remains guarded. PMID:25092194

  6. Management of Patients Admitted with Acute Decompensated Heart Failure

    PubMed Central

    Krim, Selim R.; Campbell, Patrick T.; Desai, Sapna; Mandras, Stacy; Patel, Hamang; Eiswirth, Clement; Ventura, Hector O.

    2015-01-01

    Background Hospital admission for the treatment of acute decompensated heart failure is an unfortunate certainty in the vast majority of patients with heart failure. Regardless of the etiology, inpatient treatment for acute decompensated heart failure portends a worsening prognosis. Methods This review identifies patients with heart failure who need inpatient therapy and provides an overview of recommended therapies and management of these patients in the hospital setting. Results Inpatient therapy for patients with acute decompensated heart failure should be directed at decongestion and symptom improvement. Clinicians should also treat possible precipitating events, identify comorbid conditions that may exacerbate heart failure, evaluate and update current guideline-directed medical therapy, and perform risk stratification for all patients. Finally, efforts should be made to educate patients about the importance of restricting salt and fluid, monitoring daily weights, and adhering to a graded exercise program. Conclusion Early discharge follow-up and continued optimization of guideline-directed medical therapy are key to preventing future heart failure readmissions. PMID:26413005

  7. Extracorporeal ultrafiltration therapy for acute decompensated heart failure.

    PubMed

    Pourafshar, Negiin; Karimi, Ashkan; Kazory, Amir

    2016-01-01

    Congestion is the most common reason for hospitalization of patients with acute decompensated heart failure (ADHF) and adversely impacts their outcomes. Extracorporeal ultrafiltration (UF) therapy has re-emerged as an effective strategy for decongestion in this setting. This article is intended to discuss key concepts in UF and its technique, provide a brief historical view of UF application for decongestion in ADHF, review the hemodynamic and neurohormonal effects of UF and their positive effects on the pathophysiology of ADHF, discuss the findings of the landmark trials in this field, and explain key findings of these studies as well as the apparent discrepancies in their findings. In a separate section we discuss the intricacies of renal dysfunction in ADHF as it plays a very important role in understanding the current evidence and designing futures clinical trials of UF in ADHF. In the end, the authors provide their perspective on the future role of UF in management of patients with ADHF and congestion.

  8. Prostaglandin E2 Mediates Immunosuppression in Acutely Decompensated Cirrhosis

    PubMed Central

    O’Brien, Alastair J.; Fullerton, James N.; Massey, Karen A.; Auld, Grace; Sewell, Gavin; James, Sarah; Newson, Justine; Karra, Effie; Winstanley, Alison; Alazawi, William; Garcia-Marquez, Rita; Cordoba, Juan; Nicolaou, Anna; Gilroy, Derek W.

    2017-01-01

    Patients with advanced cirrhosis experience frequent infections leading to sepsis, which carries high mortality. While innate immune dysfunction underlies this vulnerability, the precise cause remains elusive. We found prostaglandin (PGE2) elevated in acutely decompensated (AD) patients at immunosuppressive levels. Plasma from AD and end-stage liver disease (ESLD) patients suppressed macrophage cytokine secretion and bacteria killing in a PGE2 receptor-dependent manner, effects not seen in stable cirrhosis. Mouse models (bile duct ligation and CCL4-liver injury) also demonstrated elevated PGE2, which when inhibited completely restored immune competence and survival following infection. Importantly, albumin binds/inactivates PGE2 resulting in greater PGE2 bioavailability. This results in enhanced immunosuppressive effects of AD plasma in patients with low albumin levels. Administering albumin to AD patients reversed immunosuppressive properties of their plasma; protective effects recapitulated in rodent survival studies. Thus, elevated PGE2 combined with hypoalbuminemia mediates immunosuppression in AD and ESLD patients, which can be reversed with albumin. PMID:24728410

  9. Rational use of diuretics in acute decompensated heart failure.

    PubMed

    Goebel, Jason A; Van Bakel, Adrian B

    2008-09-01

    Chronic heart failure poses an enormous health care burden to the United States and other developed countries. Acute decompensated heart failure (ADHF) accounts for nearly half of the morbidity and expense of treating this disease. Most patients presenting with ADHF have symptomatic vascular congestion. Diuretics, especially loop diuretics, are the primary pharmacologic intervention used in this population. Despite their widespread use, scant data from randomized clinical trials are available to guide therapeutic choices. In addition, data from several large registries examining weight loss during hospitalization for ADHF suggest that efficacy with diuretic treatment is far from universal. Aggressive diuresis carries a significant risk of electrolyte and volume depletion, with subsequent arrhythmias, hypotension, and worsening renal function. These complications often translate into worse prognosis. Diuretic regimens used to treat ADHF must be individualized based on general knowledge of potency and pharmacokinetic and pharmacodynamic considerations. This article summarizes older and more recent literature to provide a framework for making rational treatment choices in this difficult patient population.

  10. Acute decompensated heart failure (ADHF): A comprehensive contemporary review on preventing early readmissions and postdischarge death.

    PubMed

    Rocha, Bruno M L; Menezes Falcão, Luiz

    2016-11-15

    Heart failure (HF) is an increasingly prevalent syndrome and a leading cause of both first hospitalization and readmissions. Strikingly, up to 25% of the patients are readmitted within 30 to 60-days, accounting for HF as the primary cause for readmission in the adult population. Given its poor prognosis, one could describe it as a "malignant condition". Acute decompensation is intrinsically related to increased right heart tele-diastolic pressures and often related to congestive symptoms. In-hospital strategies to adequately compensate and timely discharge patients are limited. Conversely, the fragile early postdischarge phase is a vulnerable period when one could potentially intervene cost-effectively to improve survival and to reduce morbidity. Promising transitional hospital-to-home programs may have a broader role in the near future, namely for selected higher risk patients. However, identifying patients at risk for hospital readmission has been challenging. Novel approaches, such as ferric carboxymaltose and valsartan/sacubitril, and reemerging drugs, particularly digoxin, may reduce hospitalizations. Despite this, optimizing the use of "older" therapies is still warranted. Right heart pressures monitoring may provide novel insights into promptly outpatient management. Unfortunately, randomized trials in the specific ADHF population are scarce. A novel paradigmatic approach is needed in order to suitably improve the currently poor prognosis of ADHF. Both improving survival and reducing hospitalizations are, therefore, primordial therapy goals. Lastly, no single drug has consistently proved to improve survival in HF with preserved ejection fraction (HFpEF); yet, some approaches may efficiently reduce hospitalizations. Awareness on HFpEF management beyond the failing heart is imperative.

  11. Pharmacologic strategies to preserve renal function in acute decompensated heart failure.

    PubMed

    Kumar, Sachin; Taylor, David O

    2015-02-01

    Over a million patients get hospitalized with the diagnosis of acute decompensated heart failure which poses an insurmountable financial burden on the health care system. Heart failure alone incurs over 30 billion dollars with half the cost spent towards acute hospitalizations. Majority of the treatment strategies have focused towards decongesting patients which often comes with the cost of worsening renal function. Renal dysfunction in the setting of acute decompensated heart failure portends worse morbidity and mortality. Recently, there has been a change in the focus with shift towards therapies attempting to conserve renal function. In the past decade, we have witnessed several large randomized controlled trials testing the established as well as emerging therapies in this subset of population with mixed results. This review intends to provide a comprehensive overview of the pharmacologic therapies commonly utilized in the management of acute decompensated heart failure and the body of evidence supporting these strategies.

  12. Prognostic markers of acute decompensated heart failure: the emerging roles of cardiac biomarkers and prognostic scores.

    PubMed

    Cohen-Solal, Alain; Laribi, Said; Ishihara, Shiro; Vergaro, Giuseppe; Baudet, Mathilde; Logeart, Damien; Mebazaa, Alexandre; Gayat, Etienne; Vodovar, Nicolas; Pascual-Figal, Domingo A; Seronde, Marie-France

    2015-01-01

    Rapidly assessing outcome in patients with acute decompensated heart failure is important but prognostic factors may differ from those used routinely for stable chronic heart failure. Multiple plasma biomarkers, besides the classic natriuretic peptides, have recently emerged as potential prognosticators. Furthermore, prognostic scores that combine clinical and biochemical data may also be useful. However, compared with the scores used in chronic heart failure, scores for acute decompensated heart failure have not been validated. This article reviews potential biomarkers, with a special focus on biochemical biomarkers, and possible prognostic scores that could be used by the clinician when assessing outcome in patients with acute heart failure.

  13. Sofosbuvir and ribavirin in acute hepatitis C–infected patient with decompensated cirrhosis

    PubMed Central

    Liu, Hui; Zhang, Tong; Yan, Yan

    2016-01-01

    Abstract Background: The treatment of chronic hepatitis C virus infection has been revolutionized by the advent of direct-acting antiviral agents. However, evidence of its effects on patients with acute hepatitis C (AHC) virus infection is limited. Case summary: We report the case of a patient with decompensated cirrhosis induced by autoimmune liver disease, whose condition rapidly deteriorated following AHC virus infection. The patient received sofosbuvir and ribavirin combination treatment for 12 weeks. Serum hepatitis C virus RNA remained undetectable 36 weeks after discontinuing sofosbuvir and ribavirin. Conclusion: Our findings support the use of sofosbuvir and ribavirin as a treatment in AHC patients with decompensated cirrhosis. PMID:27930559

  14. Acute metabolic decompensation due to influenza in a mouse model of ornithine transcarbamylase deficiency.

    PubMed

    McGuire, Peter J; Tarasenko, Tatiana N; Wang, Tony; Levy, Ezra; Zerfas, Patricia M; Moran, Thomas; Lee, Hye Seung; Bequette, Brian J; Diaz, George A

    2014-02-01

    The urea cycle functions to incorporate ammonia, generated by normal metabolism, into urea. Urea cycle disorders (UCDs) are caused by loss of function in any of the enzymes responsible for ureagenesis, and are characterized by life-threatening episodes of acute metabolic decompensation with hyperammonemia (HA). A prospective analysis of interim HA events in a cohort of individuals with ornithine transcarbamylase (OTC) deficiency, the most common UCD, revealed that intercurrent infection was the most common precipitant of acute HA and was associated with markers of increased morbidity when compared with other precipitants. To further understand these clinical observations, we developed a model system of metabolic decompensation with HA triggered by viral infection (PR8 influenza) using spf-ash mice, a model of OTC deficiency. Both wild-type (WT) and spf-ash mice displayed similar cytokine profiles and lung viral titers in response to PR8 influenza infection. During infection, spf-ash mice displayed an increase in liver transaminases, suggesting a hepatic sensitivity to the inflammatory response and an altered hepatic immune response. Despite having no visible pathological changes by histology, WT and spf-ash mice had reduced CPS1 and OTC enzyme activities, and, unlike WT, spf-ash mice failed to increase ureagenesis. Depression of urea cycle function was seen in liver amino acid analysis, with reductions seen in aspartate, ornithine and arginine during infection. In conclusion, we developed a model system of acute metabolic decompensation due to infection in a mouse model of a UCD. In addition, we have identified metabolic perturbations during infection in the spf-ash mice, including a reduction of urea cycle intermediates. This model of acute metabolic decompensation with HA due to infection in UCD serves as a platform for exploring biochemical perturbations and the efficacy of treatments, and could be adapted to explore acute decompensation in other types of inborn

  15. Computational modeling to predict nitrogen balance during acute metabolic decompensation in patients with urea cycle disorders.

    PubMed

    MacLeod, Erin L; Hall, Kevin D; McGuire, Peter J

    2016-01-01

    Nutritional management of acute metabolic decompensation in amino acid inborn errors of metabolism (AA IEM) aims to restore nitrogen balance. While nutritional recommendations have been published, they have never been rigorously evaluated. Furthermore, despite these recommendations, there is a wide variation in the nutritional strategies employed amongst providers, particularly regarding the inclusion of parenteral lipids for protein-free caloric support. Since randomized clinical trials during acute metabolic decompensation are difficult and potentially dangerous, mathematical modeling of metabolism can serve as a surrogate for the preclinical evaluation of nutritional interventions aimed at restoring nitrogen balance during acute decompensation in AA IEM. A validated computational model of human macronutrient metabolism was adapted to predict nitrogen balance in response to various nutritional interventions in a simulated patient with a urea cycle disorder (UCD) during acute metabolic decompensation due to dietary non-adherence or infection. The nutritional interventions were constructed from published recommendations as well as clinical anecdotes. Overall, dextrose alone (DEX) was predicted to be better at restoring nitrogen balance and limiting nitrogen excretion during dietary non-adherence and infection scenarios, suggesting that the published recommended nutritional strategy involving dextrose and parenteral lipids (ISO) may be suboptimal. The implications for patients with AA IEM are that the medical course during acute metabolic decompensation may be influenced by the choice of protein-free caloric support. These results are also applicable to intensive care patients undergoing catabolism (postoperative phase or sepsis), where parenteral nutritional support aimed at restoring nitrogen balance may be more tailored regarding metabolic fuel selection.

  16. Impact of intravenous nitroglycerin in the management of acute decompensated heart failure.

    PubMed

    den Uil, Corstiaan A; Brugts, Jasper J

    2015-02-01

    Intravenous nitroglycerin is a well-known, but underused, treatment for acute decompensated heart failure. Nitroglycerin has a rapid onset of action and short half-life and there is a clear dose-response curve on both global hemodynamics and peripheral circulation. IV nitroglycerin reduces LV and RV filling pressures and afterload. In the case of acute decompensated heart failure, there is a typical decreased bioavailability of nitric oxide (NO), which needs to be supplemented by exogenous nitrates. Additionally, there is benefit on clinical endpoints, such as fast optimization of arterial oxygenation, lower rates of mechanical ventilation, and improved survival. Drawbacks of therapy include not only side effects such as headache, resistance, and development of tolerability to nitrates but also free radical production. However, nitrates in combination with diuretics remain the cornerstone of acute decompensated heart failure treatment. We propose a more aggressive use of nitrates and a more limited use of inotropes (due to ischemic demand and pro-arrhythmogenic characteristics) in normo- or hypertensive patients with acute heart failure.

  17. Acute Heart Failure Registry: Risk Assessment Model in Decompensated Heart Failure

    PubMed Central

    Delgado, Anne; Rodrigues, Bruno; Nunes, Sara; Baptista, Rui; Marmelo, Bruno; Moreira, Davide; Gama, Pedro; Nunes, Luís; Santos, Oliveira; Cabral, Costa

    2016-01-01

    Background Heart failure (HF) is a highly prevalent syndrome. Although the long-term prognostic factors have been identified in chronic HF, this information is scarcer with respect to patients with acute HF. despite available data in the literature on long-term prognostic factors in chronic HF, data on acute HF patients are more scarce. Objectives To develop a predictor of unfavorable prognostic events in patients hospitalized for acute HF syndromes, and to characterize a group at higher risk regarding their clinical characteristics, treatment and outcomes. Methods cohort study of 600 patients admitted for acute HF, defined according to the European Society of Cardiology criteria. Primary endpoint for score derivation was defined as all-cause mortality and / or rehospitalization for HF at 12 months. For score validation, the following endpoints were used: all-cause mortality and / or readmission for HF at 6, 12 and 24 months. The exclusion criteria were: high output HF; patients with acute myocardial infraction, acute myocarditis, infectious endocarditis, pulmonary infection, pulmonary artery hypertension and severe mitral stenosis. Results 505 patients were included, and prognostic predicting factors at 12 months were identified. One or two points were assigned according to the odds ratio (OR) obtained (p < 0.05). After the total score value was determined, a 4-point cut-off was determined for each ROC curve at 12 months. Two groups were formed according to the number of points, group A < 4 points, and group B = 4 points. Group B was composed of older patients, with higher number of comorbidities and predictors of the combined endpoint at 6, 12 and 24 months, as linearly represented in the survival curves (Log rank). Conclusions This risk score enabled the identification of a group with worse prognosis at 12 months.

  18. Efficacy and safety of continuous hemodiafiltration for acute decompensated heart failure.

    PubMed

    Shiomi, Hiroki; Matsubara, Kinya; Ariyoshi, Makoto; Iwamura, Yumi; Fukui, Kensuke; Sakamoto, Tomoko; Sawanishi, Takayoshi; Shima, Masami; Furukawa, Keizo

    2010-07-01

    The mortality of heart failure patients with renal insufficiency is high, and these patients tend to develop diuretic resistance. Under these conditions, continuous hemodiafiltration (CHDF) is a possible alternative volume reduction therapy to diuretics. However, its efficacy and safety are not clear. Between April 2005 and March 2008, 248 patients with acute decompensated heart failure were admitted to the CCU of Kyoto City Hospital. Of those patients, 31 (20 volume overloaded heart failure, 11 cardiogenic shock) received CHDF therapy, and their weight loss, acute hemodynamic changes, and clinical outcome were assessed to evaluate the efficacy and safety of CHDF therapy. CHDF was performed for 6.5 +/- 6.5 days. There was no significant change in acute hemodynamics after CHDF initiation. In the volume overloaded heart failure (VH) group, significant weight loss was observed at 24 hours and 48 hours after CHDF initiation (P < 0.001). In-hospital mortality of the VH group and cardiogenic shock (CS) group were 10.0% and 54.5%, respectively. CHDF for acute decompensated heart failure (ADHF) is a safe, effective, and reliable volume reduction therapy for volume overloaded heart failure. Further investigation is required to assess the effectiveness of CHDF for cardiogenic shock.

  19. One-Year Outcomes of Acute Decompensated Systolic Heart Failure in Taiwan: Lessons from TSOC-HFrEF Registry

    PubMed Central

    Chang, Hung-Yu; Wang, Chun-Chieh; Wu, Yen-Wen; Chu, Pao-Hsien; Wu, Chih-Cheng; Hsu, Chih-Hsin; Wen, Ming-Shien; Voon, Wen-Chol; Lin, Wei-Shiang; Huang, Jin-Long; Chen, Shyh-Ming; Yang, Ning-I; Chang, Heng-Chia; Chang, Kuan-Cheng; Sung, Shih-Hsien; Shyu, Kou-Gi; Lin, Jiunn-Lee; Mar, Guang-Yuan; Chan, Kuei-Chuan; Kuo, Jen-Yuan; Wang, Ji-Hung; Chen, Zhih-Cherng; Tseng, Wei-Kung; Cherng, Wen-Jin; Yin, Wei-Hsian

    2017-01-01

    Background Heart failure (HF) is a global health problem. The Taiwan Society of Cardiology-Heart Failure with reduced Ejection Fraction (TSOC-HFrEF) registry was a multicenter, observational survey of patients admitted with HFrEF in Taiwan. The aim of this study was to report the one-year outcome in this large-cohort of hospitalized patients presenting with acute decompensated HFrEF. Methods Patients hospitalized for acute HFrEF were recruited in 21 hospitals in Taiwan. A total of 1509 patients were enrolled into the registry by the end of October 2014. Clinical status, readmission rates and dispensed medications were collected and analyzed 1 year after patient index hospitalization. Results Our study indicated that re-hospitalization rates after HFrEF were 31.9% and 38.5% at 6 and 12 months after index hospitalization, respectively. Of these patients, 9.7% of them were readmitted more than once. At 6 and 12 months after hospital discharge, all-cause mortality rates were 9.5% and 15.9%, respectively, and cardiovascular mortality rates were 6.8% and 10.5%, respectively. Twenty-three patients (1.5%) underwent heart transplantation. During a follow-up period of 1 year, 46.4% of patients were free from mortality, HF re-hospitalization, left ventricular assist device use and heart transplantation. At the conclusion of follow-up, 57.5% of patients were prescribed either with angiotensin-converting enzyme inhibitors or angiotensin receptor blockers; also, 66.3% were prescribed with beta-blockers and 40.8% were prescribed with mineralocorticoid receptor antagonists. Conclusions The TSOC-HFrEF registry showed evidence of suboptimal practice of guideline-directed medical therapy and high HF re-hospitalization rate in Taiwan. The one-year mortality rate of the TSOC-HFrEF registry remained high. Ultimately, our data indicated a need for further improvement in HF care. PMID:28344416

  20. Change in plasma volume and prognosis in acute decompensated heart failure: an observational cohort study

    PubMed Central

    Hudson, Sarah R; Chan, Daniel

    2016-01-01

    Objectives This study aimed to develop an inexpensive, readily available prognostic indicator in acute decompensated heart failure patients to guide management and improve outcome. Prognostic biomarkers for heart failure exist but are expensive and not routinely performed. Increasing plasma volume has been associated with worse outcomes. Setting UK University Teaching Hospital. Design Observational Cohort study. Participants 967 patients with acute decompensated heart failure. Methods Haemoglobin and haematocrit were measured at admission and discharge and were used to calculate the plasma volume change using the Strauss-Davis-Rosenbaum formula. Main outcome measures Endpoints were death and the composite of death and/or heart failure hospitalisation. Change in plasma volume was added to ADHERE scoring to determine predictive value. Results During follow-up, 536 died and 626 died or were hospitalised with heart failure. Multivariable Cox models showed change in plasma volume was an independent predictor of mortality (hazard ratio (HR) [95% confidence interval (CI)]: 1.150 [1.031–1.283], p = 0.012) and death or heart failure hospitalisation (HR: 1.138 [1.029–1.259], p = 0.012). Kaplan–Meier analysis of change in plasma volume tertiles for outcome measures showed significant difference for the top tertile compared to the lower two. Multivariable analysis of change in plasma volume with ADHERE scoring showed change in plasma volume change remained an independent predictor of death (HR: 1.138 [1.026–1.261], p = 0.015) and death or heart failure hospitalisation (HR: 1.129 [1.025–1.243], p = 0.014). Conclusions Change in plasma volume over an admission can be used for prognostication and adds value to the ADHERE score. Change in plasma volume can be easily and inexpensively calculated from routine blood tests. Clinically, this may facilitate targeted treatment of acute decompensated heart failure patients at greatest risk. PMID:27609799

  1. Effect and clinical prediction of worsening renal function in acute decompensated heart failure.

    PubMed

    Breidthardt, Tobias; Socrates, Thenral; Noveanu, Markus; Klima, Theresia; Heinisch, Corinna; Reichlin, Tobias; Potocki, Mihael; Nowak, Albina; Tschung, Christopher; Arenja, Nisha; Bingisser, Roland; Mueller, Christian

    2011-03-01

    We aimed to establish the prevalence and effect of worsening renal function (WRF) on survival among patients with acute decompensated heart failure. Furthermore, we sought to establish a risk score for the prediction of WRF and externally validate the previously established Forman risk score. A total of 657 consecutive patients with acute decompensated heart failure presenting to the emergency department and undergoing serial creatinine measurements were enrolled. The potential of the clinical parameters at admission to predict WRF was assessed as the primary end point. The secondary end point was all-cause mortality at 360 days. Of the 657 patients, 136 (21%) developed WRF, and 220 patients had died during the first year. WRF was more common in the nonsurvivors (30% vs 41%, p = 0.03). Multivariate regression analysis found WRF to independently predict mortality (hazard ratio 1.92, p <0.01). In a single parameter model, previously diagnosed chronic kidney disease was the only independent predictor of WRF and achieved an area under the receiver operating characteristic curve of 0.60. After the inclusion of the blood gas analysis parameters into the model history of chronic kidney disease (hazard ratio 2.13, p = 0.03), outpatient diuretics (hazard ratio 5.75, p <0.01), and bicarbonate (hazard ratio 0.91, p <0.01) were all predictive of WRF. A risk score was developed using these predictors. On receiver operating characteristic curve analysis, the Forman and Basel prediction rules achieved an area under the curve of 0.65 and 0.71, respectively. In conclusion, WRF was common in patients with acute decompensated heart failure and was linked to significantly worse outcomes. However, the clinical parameters failed to adequately predict its occurrence, making a tailored therapy approach impossible.

  2. Case Report: Exercise in a Patient with Acute Decompensated Heart Failure Receiving Positive Inotropic Therapy

    PubMed Central

    Camarda, Robert; Foley, Laura Little; Givertz, Michael M; Cahalin, Lawrence P

    2011-01-01

    Background and Purpose: The projected increase in persons with advanced heart failure and associated costs warrant the examination of exercise in patients receiving inotropic therapy. Literature supports the use of exercise and inotropic therapy in the treatment of patients with advanced heart failure. The purposes of this paper are to illustrate the use of exercise prescription and outcomes assessment with a 6-minute walk test in a patient with acute decompensated heart failure receiving tailored therapy with dobutamine and to discuss potential relationships resulting in observed improvements. Case Description: A 67-year old man was admitted to an acute care hospital with acute decompensated heart failure for tailored medical therapy including dobutamine. The patient received 14 days of tailored medical therapy, of which 12 days included exercise training by a physical therapist. Outcomes: Functional outcomes showed a clinically significant improvement in distance walked and improvement in the cardiorespiratory response. The improvement in estimated peak oxygen consumption was 7% greater than that predicted to be from tailored medical therapy. Discussion: Exercise was safely provided to a patient hospitalized with advanced heart failure on continuous inotropic therapy. The 6-minute walk test was effectively used to prescribe exercise and examine patient outcomes. PMID:21637393

  3. Comparison of the incidence of acute decompensated heart failure before and after the major tsunami in Northeast Japan.

    PubMed

    Nakamura, Motoyuki; Tanaka, Fumitaka; Nakajima, Satoshi; Honma, Miho; Sakai, Toshiaki; Kawakami, Mikio; Endo, Hiroshi; Onodera, Masayuki; Niiyama, Masanobu; Komatsu, Takashi; Sakamaki, Kentaro; Onoda, Toshiyuki; Sakata, Kiyomi; Morino, Yoshihiro; Takahashi, Tomohiro; Makita, Shinji

    2012-12-15

    On March 11, 2011, a huge tsunami attacked the northeastern coast of Japan after a magnitude 9 earthquake. No reports have investigated the impact of tsunamis on the incidence of cardiovascular disease, especially heart failure (HF). We investigated the number and clinical characteristics of hospitalized patients with acute decompensated HF (ADHF) in the east coast of Iwate hit by the tsunami (tsunami area) for a 12-week period around the disaster. For comparison with previous years, numbers of ADHF were surveyed in the corresponding area in 2009 and 2010. In addition, to elucidate the impact of the tsunami, a similar study was performed in a remote area where the tsunami had minimal effect (control area). After the disaster, the number of patients with ADHF in the tsunami area was significantly increased compared to the predisaster period (relative risk 1.97, 95% confidence interval 1.50 to 2.59). The peak was found 3 to 4 weeks after the disaster. In contrast, in the control area, no significant change in ADHF events was observed (relative risk 1.29, 95% confidence interval 0.94 to 1.78). There was a significant correlation between changes in the number of ADHF admissions and percent tsunami flood area (r = 0.73, p <0.001) or the number of shelter evacuees (r = 0.83, p <0.001). In conclusion, these findings suggest that large and sudden changes in daily life and the trauma associated with a devastating tsunami have a significant impact on the incidence of ADHF.

  4. Citric acid as the last therapeutic approach in an acute life-threatening metabolic decompensation of propionic acidaemia.

    PubMed

    Siekmeyer, Manuela; Petzold-Quinque, Stefanie; Terpe, Friederike; Beblo, Skadi; Gebhardt, Rolf; Schlensog-Schuster, Franziska; Kiess, Wieland; Siekmeyer, Werner

    2013-01-01

    The tricarboxylic acid (TCA) cycle represents the key enzymatic steps in cellular energy metabolism. Once the TCA cycle is impaired in case of inherited metabolic disorders, life-threatening episodes of metabolic decompensation and severe organ failure can arise. We present the case of a 6 ½-year-old girl with propionic acidaemia during an episode of acute life-threatening metabolic decompensation and severe lactic acidosis. Citric acid given as an oral formulation showed the potential to sustain the TCA cycle flux. This therapeutic approach may become a treatment option in a situation of acute metabolic crisis, possibly preventing severe disturbance of energy metabolism.

  5. Cardiorenal Syndrome Type 1: Renal Dysfunction in Acute Decompensated Heart Failure

    PubMed Central

    Prins, Kurt W.; Thenappan, Thenappan; Markowitz, Jeremy S.; Pritzker, Marc R.

    2016-01-01

    Objective To present a review of cardiorenal syndrome type 1 (CRS1). Methods Review of the literature. Results Acute kidney injury occurs in approximately one-third of patients with acute decompensated heart failure (ADHF) and the resultant condition was named CRS1. A growing body of literature shows CRS1 patients are at high risk for poor outcomes, and thus there is an urgent need to understand the pathophysiology and subsequently develop effective treatments. In this review we discuss prevalence, proposed pathophysiology including hemodynamic and nonhemodynamic factors, prognosticating variables, data for different treatment strategies, and ongoing clinical trials and highlight questions and problems physicians will face moving forward with this common and challenging condition. Conclusion Further research is needed to understand the pathophysiology of this complex clinical entity and to develop effective treatments. PMID:27158218

  6. Plasma asymmetric dimethylarginine and cardiovascular events in patients with acute decompensated heart failure.

    PubMed

    Dückelmann, Christina; Mittermayer, Friedrich; Haider, Dominik G; Altenberger, Johann; Wolzt, Michael

    2008-07-01

    This prospective study investigated whether plasma asymmetric dimethylarginine (ADMA) concentrations are related to cardiovascular events in patients with acute heart failure. It has been reported that increased plasma ADMA concentrations are associated with adverse cardiovascular outcome in chronic heart failure. In 118 patients with acute decompensated heart failure and impaired left ventricular function, ADMA and N-terminal pro-brain natriuretic peptide (NT-proBNP) were assessed by high-performance liquid chromatography and by an enzyme-linked immunosorbent assay, respectively. Venous blood was collected at admission and after 1 week, and clinical events were observed during follow-up. All patients (median age 73 years, 96 males) were followed up for a median of 10.7 months. A clinical endpoint (cardiac decompensation, major adverse cardiovascular event, or all-cause mortality) occurred in 66 patients. In 81 patients, changes (Delta) in ADMA or NT-proBNP between admission and a median of 7 days were available. ADMA, NT-proBNP at admission, and DeltaADMA or DeltaNT-proBNP were comparable in patients with and without a clinical endpoint. In contrast to ADMA, NT-proBNP concentrations above the median were associated with higher adjusted hazard ratio for occurrence of an endpoint (HR 2.1; 95% confidence interval 1.2-3.9; P = 0.013). An inverse relationship was observed between DeltaNT-proBNP and endpoints before (P = 0.010) and after (P = 0.015) adjustment for confounders. In patients with acute heart failure, ADMA did not detect patients at future cardiovascular risk.

  7. Pheochromocytoma presenting as acute decompensated heart failure reversed with medical therapy

    PubMed Central

    Mulla, Christopher M; Marik, Paul Ellis

    2012-01-01

    A 26-year-old woman presented to hospital with acute chest pain, hypertension, tachycardia and an elevated serum creatinine. She developed respiratory distress requiring endotracheal intubation and mechanical ventilation. She progressed to multiorgan failure due to decompensated congestive heart failure. Echocardiography demonstrated global hypokinesis and an ejection fraction of <10%. Her cardiac function improved with fluid resuscitation and β blockade, and she was eventually discharged home. She was readmitted a few days later with pancreatitis after presenting with nausea, abdominal pain and hypertension. During hospitalisation she had paroxysms of headache, nausea and diaphoresis associated with hypertension and tachycardia. A CT scan of her abdomen revealed an adrenal mass and serum metanephrine studies confirmed the diagnosis of pheochromocytoma. After fluid resuscitation and sympathetic blockade her ejection fraction improved to 55%. The patient underwent an uneventful adrenalectomy and made a complete recovery. PMID:22814979

  8. Review of vasodilators in acute decompensated heart failure: the old and the new.

    PubMed

    Carlson, Michelle D; Eckman, Peter M

    2013-07-01

    Despite substantial improvements in treatment for chronic heart failure, morbidity and mortality for acute decompensated heart failure (ADHF) remain high. Treatment of ADHF is focused on controlling symptoms rather than improving long-term outcomes. The vasodilators nitroglycerin (NTG) and sodium nitroprusside (SNP) have been used in ADHF for decades, but, since the development of nesiritide 10 years ago, interest in new vasodilators has grown. Therapies that improve not only hemodynamics and symptoms but also long-term outcomes are in high demand, and numerous new vasodilatory agents have been investigated, including various natriuretic peptides, soluble guanylyl cyclase agents, renin-angiotensin-aldosterone system-modifying agents, and others. A review of the literature shows that few of them rise to the challenge set by NTG and SNP.

  9. Continuous ultrafiltration in acute decompensated heart failure: current issues and future directions.

    PubMed

    Marenzi, Giancarlo; Morpurgo, Marco; Agostoni, Piergiuseppe

    2015-04-01

    Most patients hospitalized for acutely decompensated heart failure (ADHF) present with symptoms and signs of volume overload, which are also associated with high rates of death and re-hospitalization. Several studies have investigated the possible use of extracorporeal ultrafiltration in the management of ADHF, evaluating potential clinical benefits in terms of hospitalization and survival rates versus those of conventional diuretic therapy. Though ultrafiltration remains an extremely appealing therapeutic option for patients with AHDF, some of the most recent studies have reported conflicting results. Differences in the selection of study population, heterogeneity of the indications for the use of ultrafiltration, disparity in the ultrafiltration protocols, and high variability in the pharmacologic therapies used for the control group could explain some of these contradictory findings. The purpose of the present review is to provide an overview and an update on the mechanisms and clinical effects of ultrafiltration and on currently available evidence supporting its use in ADHF.

  10. Three-view bedside ultrasound to differentiate acute decompensated heart failure from chronic obstructive pulmonary disease.

    PubMed

    Mantuani, Daniel; Nagdev, Arun

    2013-04-01

    Identifying the cause of acute dyspnea in the emergency department is often challenging, even for the most experienced provider. Distinguishing chronic obstructive pulmonary disease from acute decompensated heart failure in the acutely dyspneic patient who presents in respiratory distress is often difficult. Patients are often unable to give a detailed history when in extremis, yet primary management needs to be initiated before further testing can be completed. Bedside diagnostic ultrasound has emerged as a tool for emergency physicians to rapidly evaluate the cardiopulmonary status in patients presenting with undifferentiated shortness of breath [1-3]. A rapid 3-view sonographic evaluation of the heart, lungs, and inferior vena cava or “Triple Scan” may be a useful tool in identifying the cause of acute dyspnea and may aid the clinician in the initial management of the critically ill dyspneic patient. We present a case where a 3-view ultrasound examination, the “Triple Scan,” allowed for detection of new onset congestive heart failure and initiation of appropriate medical therapy without waiting for further standard diagnostic testing.

  11. Circulating Omega-6, But Not Omega-3 Polyunsaturated Fatty Acids, Are Associated with Clinical Outcomes in Patients with Acute Decompensated Heart Failure

    PubMed Central

    Nagai, Toshiyuki; Honda, Yasuyuki; Sugano, Yasuo; Nishimura, Kunihiro; Nakai, Michikazu; Honda, Satoshi; Iwakami, Naotsugu; Okada, Atsushi; Asaumi, Yasuhide; Aiba, Takeshi; Noguchi, Teruo; Kusano, Kengo; Ogawa, Hisao; Yasuda, Satoshi; Anzai, Toshihisa

    2016-01-01

    Background Circulating polyunsaturated fatty acid (PUFA) levels are associated with clinical outcomes in cardiovascular diseases including coronary artery disease and chronic heart failure (HF). However, their clinical implications in acute decompensated HF (ADHF) remain unclear. The aim of this study was to investigate the clinical roles of circulating PUFAs in patients with ADHF. Methods Circulating levels of PUFAs, eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), arachidonic acid (AA) and dihomo-gamma linoleic acid (DGLA), were measured on admission in 685 consecutive ADHF patients. Adverse events were defined as all-cause death and worsening HF. Results During a median follow-up period of 560 days, 262 (38.2%) patients had adverse events. Although patients with adverse events had lower n-6 PUFA (AA + DGLA) level than those without, n-3 PUFA (EPA + DHA) level was comparable between the groups. Kaplan-Meier analyses showed that lower n-6 PUFA level on admission was significantly associated with the composite of all-cause death and worsening HF, all-cause death, cardiovascular death and worsening HF (p < 0.001, p = 0.005, p = 0.021, p = 0.019, respectively). In a multivariate Cox model, lower n-6 PUFA level was independently associated with increased risk of adverse events (HR 0.996, 95% CI: 0.993–0.999, p = 0.027). Conclusions Lower n-6 but not n-3 PUFA level on admission was significantly related to worse clinical outcomes in ADHF patients. Measurement of circulating n-6 PUFA levels on admission might provide information for identifying high risk ADHF patients. PMID:27824904

  12. Post-Exercise Heart Rate Recovery Independently Predicts Clinical Outcome in Patients with Acute Decompensated Heart Failure

    PubMed Central

    Youn, Jong-Chan; Lee, Hye Sun; Choi, Suk-Won; Han, Seong-Woo; Ryu, Kyu-Hyung; Shin, Eui-Cheol; Kang, Seok-Min

    2016-01-01

    Background Post-exercise heart rate recovery (HRR) is an index of parasympathetic function associated with clinical outcome in patients with chronic heart failure. However, its relationship with the pro-inflammatory response and prognostic value in consecutive patients with acute decompensated heart failure (ADHF) has not been investigated. Methods We measured HRR and pro-inflammatory markers in 107 prospectively and consecutively enrolled, recovered ADHF patients (71 male, 59 ± 15 years, mean ejection fraction 28.9 ± 14.2%) during the pre-discharge period. The primary endpoint included cardiovascular (CV) events defined as CV mortality, cardiac transplantation, or rehospitalization due to HF aggravation. Results The CV events occurred in 30 (28.0%) patients (5 cardiovascular deaths and 7 cardiac transplantations) during the follow-up period (median 214 days, 11–812 days). When the patients with ADHF were grouped by HRR according to the Contal and O’Quigley’s method, low HRR was shown to be associated with significantly higher levels of serum monokine-induced by gamma interferon (MIG) and poor clinical outcome. Multivariate Cox regression analysis revealed that low HRR was an independent predictor of CV events in both enter method and stepwise method. The addition of HRR to a model significantly increased predictability for CV events across the entire follow-up period. Conclusion Impaired post-exercise HRR is associated with a pro-inflammatory response and independently predicts clinical outcome in patients with ADHF. These findings may explain the relationship between autonomic dysfunction and clinical outcome in terms of the inflammatory response in these patients. PMID:27135610

  13. Decrease in NTproBNP plasma levels indicates clinical improvement of acute decompensated heart failure.

    PubMed

    Di Somma, Salvatore; Magrini, Laura; Mazzone, Marinella; De Leva, Raffaella; Tabacco, Fabio; Marino, Rossella; Talucci, Veronica; Ferri, Enrico; Forte, Paola; Cardelli, Patrizia; Gentiloni, Nicola; Pittoni, Valerio

    2007-03-01

    Thirty-seven consecutive patients with acute decompensated heart failure (ADHF) admitted to emergency departments for acute dyspnea were investigated. Ten patients with acute exacerbation of chronic obstructive pulmonary disease and 10 patients with hypertension crisis were also included as controls. For each patient, a plasma amino-terminal pro-B-type natriuretic peptide (NTproBNP) concentration measurement was performed at admission, 4, 12, and 24 hours later, and on the day of discharge. In patients with ADHF, the observation of a progressive reduction to a complete relief of symptoms of heart failure was accompanied by a reduction of 58% of NTproBNP plasma levels on the day of discharge. Amelioration of symptoms was accompanied by improvement of physiologic parameters and New York Heart Association functional class. In the control population (chronic obstructive pulmonary disease and hypertension crisis patients), no significant variation of NTproBNP levels in comparison with those at admission was found at each time point. In conclusion, a plasma profile obtained with sequential measurements indicates that a significant decrease in NTproBNP levels is associated with the clinical improvement of patients with ADHF at the time of discharge.

  14. Outcomes of patients hospitalized for acute decompensated heart failure: does nesiritide make a difference?

    PubMed Central

    Carroll, Richard J; Mulla, Zuber D; Hauck, Loran D; Westbrook, Audrey

    2007-01-01

    Background Nesiritide is indicated in the treatment of acute decompensated heart failure. However, a recent meta-analysis reported that nesiritide may be associated with an increased risk of death. Our goal was to evaluate the impact of nesiritide treatment on four outcomes among adults hospitalized for congestive heart failure (CHF) during a three-year period. Methods CHF patients discharged between 1/1/2002 and 12/31/2004 from the Adventist Health System, a national, not-for-profit hospital system, were identified. 25,330 records were included in this retrospective study. Nesiritide odds ratios (OR) were adjusted for various factors including nine medications and/or an APR-DRG severity score. Results Initially, treatment with nesiritide was found to be associated with a 59% higher odds of hospital mortality (Unadjusted OR = 1.59, 95% confidence interval [CI]: 1.31–1.93). Adjusting for race, low economic status, APR-DRG severity of illness score, and the receipt of nine medications yielded a nonsignificant nesiritide OR of 1.07 for hospital death (95% CI: 0.85–1.35). Nesiritide was positively associated with the odds of prolonged length of stay (all adjusted ORs = 1.66) and elevated pharmacy cost (all adjusted ORs > 5). Conclusion In this observational study, nesiritide therapy was associated with increased length of stay and pharmacy cost, but not hospital mortality. Randomized trials are urgently needed to better define the efficacy, if any, of nesiritide in the treatment of decompensated heart failure. PMID:18039381

  15. Decongestive treatment of acute decompensated heart failure: cardiorenal implications of ultrafiltration and diuretics.

    PubMed

    Freda, Benjamin J; Slawsky, Mara; Mallidi, Jaya; Braden, Gregory L

    2011-12-01

    In patients with acute decompensated heart failure (ADHF), treatment aimed at adequate decongestion of the volume overloaded state is essential. Despite diuretic therapy, many patients remain volume overloaded and symptomatic. In addition, adverse effects related to diuretic treatment are common, including worsening kidney function and electrolyte disturbances. The development of decreased kidney function during treatment affects the response to diuretic therapy and is associated with important clinical outcomes, including mortality. The occurrence of diuretic resistance and the morbidity and mortality associated with diuretic therapy has stimulated interest to develop effective and safe treatment strategies that maximize decongestion and minimize decreased kidney function. During the last few decades, extracorporeal ultrafiltration has been used to remove fluid from diuretic-refractory hypervolemic patients. Recent clinical studies using user-friendly machines have suggested that ultrafiltration may be highly effective for decongesting patients with ADHF. Many questions remain regarding the comparative impact of diuretics and ultrafiltration on important clinical outcomes and adverse effects, including decreased kidney function. This article serves as a summary of key clinical studies addressing these points. The overall goal is to assist practicing clinicians who are contemplating the use of ultrafiltration for a patient with ADHF.

  16. Effects of Beta-Blocker Withdrawal in Acute Decompensated Heart Failure

    PubMed Central

    Prins, Kurt W.; Neill, John M.; Tyler, John O.; Eckman, Peter M.; Duval, Sue

    2015-01-01

    OBJECTIVES This study sought to evaluate the effects of beta-blocker withdrawal in acute decompensated heart failure (ADHF). BACKGROUND Published reports showed trends for either no harm or increased risk of in-hospital mortality, short-term mortality, and rehospitalization rates in patients admitted for ADHF that discontinued beta-blockers; however, a comprehensive analysis has not been conducted. METHODS Relevant studies from January 2000 through January 2015 were identified in the PubMed, EMBASE, and COCHRANE electronic databases. Where appropriate data were available, weighted relative risks were estimated using random-effects meta-analysis techniques. RESULTS Five observational studies and 1 randomized clinical trial (n = 2,704 patients who continued beta-blocker therapy and n = 439 patients who discontinued beta-blocker therapy) that reported the short-term effects of beta-blocker withdrawal in ADHF were included in the analyses. In 2 studies, beta-blocker withdrawal significantly increased risk of in-hospital mortality (risk ratio: 3.72; 95% confidence interval [CI]: 1.51 to 9.14). Short-term mortality (relative risk: 1.61; 95% CI: 1.04 to 2.49; 4 studies) and combined short-term rehospitalization or death (relative risk: 1.59; 95% CI: 1.03 to 2.45; 4 studies) were also significantly increased. CONCLUSIONS Discontinuation of beta-blockers in patients admitted with ADHF was associated with significantly increased in-hospital mortality, short-term mortality, and the combined endpoint of short-term rehospitalization or mortality. These data suggest beta-blockers should be continued in ADHF patients if their clinical picture allows. PMID:26251094

  17. Assessing validity by comparing transition and static measures of dyspnea in patients with acute decompensated heart failure.

    PubMed

    Smithline, Howard A; Caglar, Selin; Blank, Fidela S J

    2010-01-01

    This study assessed the convergent validity of 2 dyspnea measures, the transition measure and the change measure, by comparing them with each other in patients admitted to the hospital with acute decompensated heart failure. Static measures of dyspnea were obtained at baseline (pre-static measure) and at time 1 hour and 4 hour (post-static measures). The change measure was calculated as the difference between the pre-static and post-static measures. Transition measures were obtained at time 1 hour and 4 hour. Visual analog scales and Likert scales were used. Both physicians and patients measured the dyspnea independently. A total of 112 patients had complete data sets at time 0 and 1 hour and 86 patients had complete data sets at all 3 time points. Correlations were calculated between the transition measures and static measures (pre-static, post-static, and change measure). Bland-Altman plots were generated and the mean difference and limits of agreement between the transition measures and the change measures were calculated. In general, short-term dyspnea assessment using transition measures and serial static measures can not be used to validate each other in this population of patients being admitted with acute decompensated heart failure.

  18. Forensic Analysis Reveals Acute Decompensation of Chronic Heart Failure in a 3500-Year-Old Egyptian Dignitary.

    PubMed

    Bianucci, Raffaella; Loynes, Robert D; Sutherland, M Linda; Lallo, Rudy; Kay, Gemma L; Froesch, Philippe; Pallen, Mark J; Charlier, Philippe; Nerlich, Andreas G

    2016-09-01

    Naturally preserved and embalmed bodies from archeological contexts represent a powerful source of information for forensic investigators. They allow one to ascertain pathology, cause of death, to enhance diagnostic methodology, and to improve the analysis of altered remains. We investigated the complete head and lung remnants of a 3,500-year-old Egyptian dignitary by radiological, microscopic, and genetic approaches. The individual, a middle-aged male, suffered from severe periodontitis, mild atherosclerosis, and experienced cardiogenic pulmonary insufficiency with recurrent mini-bleeds and pulmonary edema. Histology and ancient DNA analyses excluded the presence of Mycobacterium tuberculosis or of any other pathogenic species. Based on our collection of evidence, we propose that acute decompensation complicating chronic cardiac insufficiency was the likely cause of death. The underlying causes for this failure remain unknown although chronic hypertension appears to be the most likely candidate. Our finding represents the earliest reported case of chronic heart failure in ancient mummies.

  19. Meta-Analysis of Ultrafiltration versus Diuretics Treatment Option for Overload Volume Reduction in Patients with Acute Decompensated Heart Failure

    PubMed Central

    Barkoudah, Ebrahim; Kodali, Sindhura; Okoroh, Juliet; Sethi, Rosh; Hulten, Edward; Suemoto, Claudia; Bittencourt, Marcio Sommer

    2015-01-01

    Introduction Although diuretics are mainly used for the treatment of acute decompensated heart failure (ADHF), inadequate responses and complications have led to the use of extracorporeal ultrafiltration (UF) as an alternative strategy for reducing volume overloads in patients with ADHF. Objective The aim of our study is to perform meta-analysis of the results obtained from studies on extracorporeal venous ultrafiltration and compare them with those of standard diuretic treatment for overload volume reduction in acute decompensated heart failure. Methods MEDLINE, EMBASE, and the Cochrane Central Register of Controlled Trials databases were systematically searched using a pre‑specified criterion. Pooled estimates of outcomes after 48 h (weight change, serum creatinine level, and all-cause mortality) were computed using random effect models. Pooled weighted mean differences were calculated for weight loss and change in creatinine level, whereas a pooled risk ratio was used for the analysis of binary all-cause mortality outcome. Results A total of nine studies, involving 613 patients, met the eligibility criteria. The mean weight loss in patients who underwent UF therapy was 1.78 kg [95% Confidence Interval (CI): −2.65 to −0.91 kg; p < 0.001) more than those who received standard diuretic therapy. The post-intervention creatinine level, however, was not significantly different (mean change = −0.25 mg/dL; 95% CI: −0.56 to 0.06 mg/dL; p = 0.112). The risk of all-cause mortality persisted in patients treated with UF compared with patients treated with standard diuretics (Pooled RR = 1.00; 95% CI: 0.64–1.56; p = 0.993). Conclusion Compared with standard diuretic therapy, UF treatment for overload volume reduction in individuals suffering from ADHF, resulted in significant reduction of body weight within 48 h. However, no significant decrease of serum creatinine level or reduction of all-cause mortality was observed. PMID:25626761

  20. Influence of Spironolactone on Matrix Metalloproteinase-2 in Acute Decompensated Heart Failure.

    PubMed

    Ferreira, João Pedro; Santos, Mário; Oliveira, José Carlos; Marques, Irene; Bettencourt, Paulo; Carvalho, Henrique

    2015-01-23

    Background: Matrix metalloproteinases (MMPs) are a family of enzymes important for the resorption of extracellular matrices, control of vascular remodeling and repair. Increased activity of MMP2 has been demonstrated in heart failure, and in acutely decompensated heart failure (ADHF) a decrease in circulating MMPs has been demonstrated along with successful treatment. Objective: Our aim was to test the influence of spironolactone in MMP2 levels. Methods: Secondary analysis of a prospective, interventional study including 100 patients with ADHF. Fifty patients were non-randomly assigned to spironolactone (100 mg/day) plus standard ADHF therapy (spironolactone group) or standard ADHF therapy alone (control group). Results: Spironolactone group patients were younger and had lower creatinine and urea levels (all p < 0.05). Baseline MMP2, NT-pro BNP and weight did not differ between spironolactone and control groups. A trend towards a more pronounced decrease in MMP2 from baseline to day 3 was observed in the spironolactone group (-21 [-50 to 19] vs 1.5 [-26 to 38] ng/mL, p = 0.06). NT-pro BNP and weight also had a greater decrease in the spironolactone group. The proportion of patients with a decrease in MMP2 levels from baseline to day 3 was also likely to be greater in the spironolactone group (50% vs 66.7%), but without statistical significance. Correlations between MMP2, NT-pro BNP and weight variation were not statistically significant. Conclusion: MMP2 levels are increased in ADHF. Patients treated with spironolactone may have a greater reduction in MMP2 levels.Fundamento: As metaloproteinases de matriz (MMPs) constituem uma família de enzimas importantes para a reabsorção da matriz extracelular e controle do remodelamento e da reparação vasculares. Demonstrou-se aumento da atividade de MMP2 na insuficiência cardíaca, e, na insuficiência cardíaca agudamente descompensada (ICAD), demonstrou-se uma diminuição nas MMPs circulantes juntamente com o

  1. TSOC-HFrEF Registry: A Registry of Hospitalized Patients with Decompensated Systolic Heart Failure: Description of Population and Management

    PubMed Central

    Wang, Chun-Chieh; Chang, Hung-Yu; Yin, Wei-Hsian; Wu, Yen-Wen; Chu, Pao-Hsien; Wu, Chih-Cheng; Hsu, Chih-Hsin; Wen, Ming-Shien; Voon, Wen-Chol; Lin, Wei-Shiang; Huang, Jin-Long; Chen, Shyh-Ming; Yang, Ning-I; Chang, Heng-Chia; Chang, Kuan-Cheng; Sung, Shih-Hsien; Shyu, Kou-Gi; Lin, Jiunn-Lee; Mar, Guang-Yuan; Chan, Kuei-Chuan; Kuo, Jen-Yuan; Wang, Ji-Hung; Chen, Zhih-Cherng; Tseng, Wei-Kung; Cherng, Wen-Jin

    2016-01-01

    Introduction Heart failure (HF) is a medical condition with a rapidly increasing incidence both in Taiwan and worldwide. The objective of the TSOC-HFrEF registry was to assess epidemiology, etiology, clinical management, and outcomes in a large sample of hospitalized patients presenting with acute decompensated systolic HF. Methods The TSOC-HFrEF registry was a prospective, multicenter, observational survey of patients presenting to 21 medical centers or teaching hospitals in Taiwan. Hospitalized patients with either acute new-onset HF or acute decompensation of chronic HFrEF were enrolled. Data including demographic characteristics, medical history, primary etiology of HF, precipitating factors for HF hospitalization, presenting symptoms and signs, diagnostic and treatment procedures, in-hospital mortality, length of stay, and discharge medications, were collected and analyzed. Results A total of 1509 patients were enrolled into the registry by the end of October 2014, with a mean age of 64 years (72% were male). Ischemic cardiomyopathy and dilated cardiomyopathy were diagnosed in 44% and 33% of patients, respectively. Coronary artery disease, hypertension, diabetes, and chronic renal insufficiency were the common comorbid conditions. Acute coronary syndrome, non-compliant to treatment, and concurrent infection were the major precipitating factors for acute decompensation. The median length of hospital stay was 8 days, and the in-hospital mortality rate was 2.4%. At discharge, 62% of patients were prescribed either angiotensin-converting enzyme-inhibitors or angiotensin receptor blockers, 60% were prescribed beta-blockers, and 49% were prescribed mineralocorticoid receptor antagonists. Conclusions The TSOC-HFrEF registry provided important insights into the current clinical characteristics and management of hospitalized decompensated systolic HF patients in Taiwan. One important observation was that adherence to guideline-directed medical therapy was suboptimal

  2. Clinical factors associated with early readmission among acutely decompensated heart failure patients

    PubMed Central

    Pierre-Louis, Bredy; Rodriques, Shareen; Gorospe, Vanessa; Guddati, Achuta K.; Ahn, Chul; Wright, Maurice

    2016-01-01

    Introduction Congestive heart failure (CHF) is a common cause of hospital readmission. Material and methods A retrospective study was conducted at Harlem Hospital in New York City. Data were collected for 685 consecutive adult patients admitted for decompensated CHF from March, 2009 to December, 2012. Variables including patient demographics, comorbidities, laboratory studies, and medical therapy were compared between CHF patient admissions resulting in early CHF readmission and not resulting in early CHF readmission. Results Clinical factors found to be independently significant for early CHF readmission included chronic obstructive pulmonary disease (odds ratio (OR) = 6.4), HIV infection (OR = 3.4), African-American ethnicity (OR = 2.2), systolic heart failure (OR = 1.9), atrial fibrillation (OR = 2.3), renal disease with glomerular filtration rate < 30 ml/min (OR = 2.7), evidence of substance abuse (OR = 1.7), and absence of angiotensin-converting enzyme inhibitors or angiotensin receptor blocker therapy after discharge (OR = 1.8). The ORs were used to develop a scoring system regarding the risk for early readmission. Conclusions Identifying patients with clinical factors associated with early CHF readmission after an index hospitalization for CHF using the proposed scoring system would allow for an early CHF readmission risk stratification protocol to target particularly high-risk patients. PMID:27279845

  3. Recurrent Acute Decompensated Heart Failure Owing to Severe Iron Deficiency Anemia Caused by Inappropriate Habitual Bloodletting

    PubMed Central

    Lim, Woo-Hyun; Kim, Hack-Lyoung; Kim, Ki-Hwan; Na, Sang Hoon; Lee, Hyun-Jung; Kang, Eun Gyu; Seo, Jae-Bin; Chung, Woo-Young; Zo, Joo-Hee; Hong, Jung Ae; Kim, Kwangyoun; Kim, Myung-A

    2015-01-01

    A 68-year-old woman visited the emergency department twice with symptoms of acute heart failure including shortness of breath, general weakness, and abdominal distension. Laboratory findings showed extremely low level of serum hemoglobin at 1.4 g/dL. Echocardiographic examination demonstrated dilated left ventricular cavity with systolic dysfunction and moderate amount of pericardial effusion. In this patient, acute heart failure due to severe iron deficiency anemia was caused by inappropriate habitual bloodletting. PMID:26755934

  4. Acute-on-chronic and Decompensated Chronic Liver Failure: Definitions, Epidemiology, and Prognostication.

    PubMed

    Olson, Jody C

    2016-07-01

    Chronic liver disease is the fifth leading cause of death worldwide and represents a major burden for the health care community. Cirrhosis is a progressive disease resulting in end-stage liver failure, which in the absence of liver transplantation is fatal. Acute-on-chronic liver failure carries high short-term mortality but is potentially reversible. Viral hepatitis, alcohol, and nonalcoholic fatty liver disease remain the principal causes of liver disease. Though treatments exist for hepatitis B and C, they remain unavailable to many with these diseases. This article reviews the epidemiology of advanced liver disease and the concept of acute-on-chronic liver failure.

  5. Pathogenesis of cardiorenal syndrome type 1 in acute decompensated heart failure: workgroup statements from the eleventh consensus conference of the Acute Dialysis Quality Initiative (ADQI).

    PubMed

    Haase, Michael; Müller, Christian; Damman, Kevin; Murray, Patrick T; Kellum, John A; Ronco, Claudio; McCullough, Peter A

    2013-01-01

    Pathophysiological mechanisms of cardiorenal syndromes (CRS) types 1-5 are still sparsely characterized. In an attempt to address this issue, a consensus conference on CRS was held in Venice, Italy, in November 2012 under the auspices of the Acute Dialysis Quality Initiative (ADQI). Working group 1 discussed monodirectional mechanisms of CRS type 1 which is characterized by a rapid worsening of cardiac function leading to acute kidney injury (AKI). Pre-conference we performed a systematic search and review of the available literature using a modified Delphi analysis. Hereby identified and in this review discussed questions were: (i) What are the predominant pathophysiologic mechanisms of CRS type 1 in acute decompensated heart failure? (ii) Could biomarker profiling identify pathomechanisms or hemodynamic phenotype of patients with CRS type 1? Could predictive biomarkers improve renal safety of therapy in CRS type 1? (iii) How do the timing, severity and duration relate to the mechanisms and outcomes of CRS type 1? In summary, after discussion and appraisal of the best available evidence, working group 1 makes consensus recommendations for future research on pathologic mechanisms of CRS type 1 and recommendations for clinical practice where treatment is in either proof or disproof of a mechanism.

  6. Point-of-Care, Ultraportable Echocardiography Predicts Diuretic Response in Patients Admitted with Acute Decompensated Heart Failure

    PubMed Central

    Krishnan, Dena K.; Pawlaczyk, Barbara; McCullough, Peter A.; Enright, Susan; Kunadi, Arvind; Vanhecke, Thomas E.

    2016-01-01

    BACKGROUND Routine management of patients with acute decompensated heart failure (ADHF) requires careful attentiveness to fluid status and diuretic treatment efficacy. New advances in ultrasound have made ultraportable echocardiography (UE) available to physicians for point-of-care use. The purpose of this study is to explore physiologic measures of intravascular fluid volume derived from UE and explore predictors of diuretic response in ADHF. METHODS Various echocardiography imaging measurements, particularly diameter and collapse of inferior vena cava (IVC), were collected from 77 patients admitted with a primary diagnosis of ADHF. Patients were divided into two groups based on whether or not they achieved a net negative fluid output of 3 L within 48 hours. The demographic information, serum laboratory markers, and physical characteristics of the subjects were obtained to correlate with daily ultrasound measurements. Univariate and multivariate analyses were used to compare diuretic “responders” to “nonresponders.” RESULTS A negative change in the IVC diameter at 48 hours was robust in prediction of diuretic response. For every 1 mm decrease in the IVC diameter at 48 hours, there was an odds ratio of 1.62 (95% CI: 1.20–2.19) for responding to diuretic therapy independent of other variables including baseline renal filtration function and blood B-type natriuretic peptide. CONCLUSION Assessment of central venous pressure as a proxy for passive renal congestion independently predicts initial diuretic response in ADHF. Future research is needed to further understand the individual variation in response to loop diuresis and to identify optimal treatment approaches that utilize anatomic and physiologic measures such as venous ultrasound. PMID:28008296

  7. Hypotension During Hospitalization for Acute Heart Failure Is Independently Associated With 30-Day Mortality: Findings from ASCEND-HF

    PubMed Central

    Patel, Priyesh A.; Heizer, Gretchen; O’Connor, Christopher M.; Schulte, Phillip J.; Dickstein, Kenneth; Ezekowitz, Justin A.; Armstrong, Paul W.; Hasselblad, Vic; Mills, Roger M.; McMurray, John J.; Starling, Randall C.; Wilson Tang, W. H.; Califf, Robert M.; Hernandez, Adrian F.

    2015-01-01

    Background Outcomes associated with episodes of hypotension while hospitalized are not well understood. Methods and Results Using data from ASCEND-HF, we assessed factors associated with inhospital hypotension and subsequent 30-day outcomes. Patients were classified as having symptomatic or asymptomatic hypotension. Multivariable logistic regression was used to determine factors associated with in-hospital hypotension, and Cox proportional hazards models were used to assess the association between hypotension and 30-day outcomes. We also tested for treatment interaction with nesiritide on 30-day outcomes and the association between inhospital hypotension and renal function at hospital discharge. Overall, 1555/7141 (21.8%) patients had an episode of hypotension, of which 73.1% were asymptomatic and 26.9% were symptomatic. Factors strongly associated with in-hospital hypotension included randomization to nesiritide (odds ratio [OR] 1.98, 95% confidence interval [CI] 1.76–2.23; p<0.001), chronic metolazone therapy (OR 1.74, 95% CI 1.17–2.60; p<0.001), and baseline orthopnea (OR 1.31, 95% CI 1.13–1.52; p=0.001) or S3 gallop (OR 1.21, 95% CI 1.06–1.40; p=0.006). In-hospital hypotension was associated with increased hazards of 30-day mortality (hazard ratio [HR] 2.03, 95% CI 1.57–2.61; p<0.001), 30-day heart failure (HF) hospitalization or mortality (HR 1.58, 95% CI 1.34–1.86; p<0.001), and 30-day all-cause hospitalization or mortality (HR 1.40, 95% CI 1.22–1.61; p<0.001). Nesiritide had no interaction on the relationship between hypotension and 30-day outcomes (interaction p=0.874 for death, p=0.908 for death/HF hospitalization, p=0.238 death/all-cause hospitalization). Conclusions Hypotension while hospitalized for acute decompensated HF is an independent risk factor for adverse 30-day outcomes, and its occurrence highlights the need for modified treatment strategies. Clinical Trial Registration URL: http://www.clinicaltrials.gov. Unique identifier: NCT

  8. Assessing Risk and Preventing 30-Day Readmissions in Decompensated Heart Failure: Opportunity to Intervene?

    PubMed

    Dunbar-Yaffe, Richard; Stitt, Audra; Lee, Joseph J; Mohamed, Shanas; Lee, Douglas S

    2015-10-01

    Heart failure (HF) patients are at high risk of hospital readmission, which contributes to substantial health care costs. There is great interest in strategies to reduce rehospitalization for HF. However, many readmissions occur within 30 days of initial hospital discharge, presenting a challenge for interventions to be instituted in a short time frame. Potential strategies to reduce readmissions for HF can be classified into three different forms. First, patients who are at high risk of readmission can be identified even before their initial index hospital discharge. Second, ambulatory remote monitoring strategies may be instituted to identify early warning signs before acute decompensation of HF occurs. Finally, strategies may be employed in the emergency department to identify low-risk patients who may not need hospital readmission. If symptoms improve with initial therapy, low-risk patients could be referred to specialized, rapid outpatient follow-up care where investigations and therapy can occur in an outpatient setting.

  9. Therapeutic effects of intravenous urapidil in elderly patients with hypertension and acute decompensated heart failure: A pilot clinical trial

    PubMed Central

    YANG, WEI; ZHOU, YU-JIE; FU, YAN; QIN, JIAN; TAN, SHU; CHEN, XIAO-MIN; GUO, JIN-CHENG; WANG, DE-ZHAO; ZHAN, HONG; GUAN, WEI; XU, YA-WEI; HE, JING-YU; LI, JING; HUA, QI

    2016-01-01

    Urapidil has been proposed to be an effective vasodilator for the treatment of acute decompensated heart failure (ADHF); however, its effect on cardiac function, as compared with that of nitroglycerin, in elderly patients with hypertension and ADHF has yet to be determined. In the present study, a multicenter, open-label clinical trial was performed, in which 120 elderly patients with hypertension and ADHF were randomly assigned to the treatment (50–400 µg/min intravenous urapidil) or control group (5–40 µg/min intravenous nitroglycerin). The dosages of the medications were adjusted according to the blood pressure of the patients. The systolic and diastolic blood pressure, heart rate and serum level of N-terminal pro B-type natriuretic peptide (NT-proBNP) were evaluated at hospital admission and at days 1, 2, 3 and 7 after treatment. In addition, the left ventricular function was assessed by measuring the left ventricular ejection fraction (LVEF) and left ventricular end-diastolic volume at hospital admission and at days 2 and 7 after treatment. The results indicated that intravenous administration of urapidil and nitroglycerin were effective in lowering the blood pressure and heart rate within 7 days, with no significant differences observed between the two groups (P>0.05). By contrast, greater reduction in the serum NT-proBNP level (2,410.4±546.1 vs. 4,234.1±876.4 pg/ml; P<0.05) and greater improvement in the LVEF (55.3±3.4 vs. 45.2±2.4%; P<0.05) were observed in the urapidil-treated group, as compared with the nitroglycerin-treated group. No adverse events were reported during the treatment period in the two groups. The clinical outcomes at 6 months following discharge were evaluated and were not found to be significantly different between the two groups. In conclusion, the present results of the present study suggested that urapidil was as effective as nitroglycerin in controlling blood pressure and heart rate and was more effective in improving

  10. Efficacy and Safety of 1-Hour Infusion of Recombinant Human Atrial Natriuretic Peptide in Patients With Acute Decompensated Heart Failure

    PubMed Central

    Wang, Guogan; Wang, Pengbo; Li, Yishi; Liu, Wenxian; Bai, Shugong; Zhen, Yang; Li, Dongye; Yang, Ping; Chen, Yu; Hong, Lang; Sun, Jianhui; Chen, Junzhu; Wang, Xian; Zhu, Jihong; Hu, Dayi; Li, Huimin; Wu, Tongguo; Huang, Jie; Tan, Huiqiong; Zhang, Jian; Liao, Zhongkai; Yu, Litian; Mao, Yi; Ye, Shaodong; Feng, Lei; Hua, Yihong; Ni, Xinhai; Zhang, Yuhui; Wang, Yang; Li, Wei; Luan, Xiaojun; Sun, Xiaolu; Wang, Sijia

    2016-01-01

    Abstract The aim of the study was to evaluate the efficacy and safety of 1-h infusion of recombinant human atrial natriuretic peptide (rhANP) in combination with standard therapy in patients with acute decompensated heart failure (ADHF). This was a phase III, randomized, double-blind, placebo-controlled, multicenter trial. Eligible patients with ADHF were randomized to receive a 1-h infusion of either rhANP or placebo at a ratio of 3:1 in combination with standard therapy. The primary endpoint was dyspnea improvement (a decrease of at least 2 grades of dyspnea severity at 12 h from baseline). Reduction in pulmonary capillary wedge pressure (PCWP) 1 h after infusion was the co-primary endpoint for catheterized patients. Overall, 477 patients were randomized: 358 (93 catheterized) patients received rhANP and 118 (28 catheterized) received placebo. The percentage of patients with dyspnea improvement at 12 h was higher, although not statistically significant, in the rhANP group than in the placebo group (32.0% vs 25.4%, odds ratio=1.382, 95% confidence interval [CI]: 0.863–2.212, P = 0.17). Reduction in PCWP at 1 h was significantly greater in patients treated with rhANP than in patients treated with placebo (−7.74 ± 5.95 vs −1.82 ± 4.47 mm Hg, P < 0.001). The frequencies of adverse events and renal impairment within 3 days of treatment were similar between the 2 groups. Mortality at 1 month was 3.1% in the rhANP group vs 2.5% in the placebo group (hazard ratio = 1.21, 95% CI: 0.34–4.26; P > 0.99). 1-h rhANP infusion appears to result in prompt, transient hemodynamic improvement with a small, nonsignificant, effect on dyspnea in ADHF patients receiving standard therapy. The safety of 1-h infusion of rhANP seems to be acceptable. (WHO International Clinical Trials Registry Platform [ICTRP] number, ChiCTR-IPR-14005719.) PMID:26945407

  11. Impact of decreased serum albumin levels on acute kidney injury in patients with acute decompensated heart failure: a potential association of atrial natriuretic peptide.

    PubMed

    Takaya, Yoichi; Yoshihara, Fumiki; Yokoyama, Hiroyuki; Kanzaki, Hideaki; Kitakaze, Masafumi; Goto, Yoichi; Anzai, Toshihisa; Yasuda, Satoshi; Ogawa, Hisao; Kawano, Yuhei; Kangawa, Kenji

    2017-02-07

    Although hypoalbuminemia at admission is a risk for acute kidney injury (AKI) and mortality in patients with acute decompensated heart failure (ADHF), the clinical significance of decreased serum albumin levels (DAL) during ADHF therapy has not been elucidated. This study aimed to evaluate whether DAL was associated with AKI, and whether intravenous atrial natriuretic peptide (ANP) administration, which provides an effective treatment for ADHF but promotes albumin extravasation, was associated with DAL and AKI. A total of 231 consecutive patients with ADHF were enrolled. AKI was defined as ≥0.3 mg/dl absolute or 1.5-fold increase in serum creatinine levels within 48 h. AKI occurred in 73 (32%) of the 231 patients during ADHF therapy. The median value of decreases in serum albumin levels was 0.3 g/dl at 7 days after admission. When DAL was defined as ≥0.3 g/dl decrease in serum albumin levels, DAL occurred in 113 patients, and was independently associated with AKI. Of the 231 patients, 73 (32%) were treated with intravenous ANP. DAL occurred more frequently in patients receiving ANP than in those not receiving ANP (77 vs. 36%, p < 0.001), and ANP was independently associated with DAL. The incidence of AKI was higher in patients receiving ANP than in those not receiving ANP (48 vs. 24%, p < 0.001). ANP was independently associated with AKI. In conclusion, DAL is associated with AKI. Intravenous ANP administration may be one of the promoting factors of DAL, which leads to AKI, indicating a possible novel mechanism of AKI.

  12. Modification in CSF specific gravity in acutely decompensated cirrhosis and acute on chronic liver failure independent of encephalopathy, evidences for an early blood-CSF barrier dysfunction in cirrhosis.

    PubMed

    Weiss, Nicolas; Rosselli, Matteo; Mouri, Sarah; Galanaud, Damien; Puybasset, Louis; Agarwal, Banwari; Thabut, Dominique; Jalan, Rajiv

    2017-04-01

    Although hepatic encephalopathy (HE) on the background of acute on chronic liver failure (ACLF) is associated with high mortality rates, it is unknown whether this is due to increased blood-brain barrier permeability. Specific gravity of cerebrospinal fluid measured by CT is able to estimate blood-cerebrospinal fluid-barrier permeability. This study aimed to assess cerebrospinal fluid specific gravity in acutely decompensated cirrhosis and to compare it in patients with or without ACLF and with or without hepatic encephalopathy. We identified all the patients admitted for acute decompensation of cirrhosis who underwent a brain CT-scan. Those patients could present acute decompensation with or without ACLF. The presence of hepatic encephalopathy was noted. They were compared to a group of stable cirrhotic patients and healthy controls. Quantitative brain CT analysis used the Brainview software that gives the weight, the volume and the specific gravity of each determined brain regions. Results are given as median and interquartile ranges and as relative variation compared to the control/baseline group. 36 patients presented an acute decompensation of cirrhosis. Among them, 25 presented with ACLF and 11 without ACLF; 20 presented with hepatic encephalopathy grade ≥ 2. They were compared to 31 stable cirrhosis patients and 61 healthy controls. Cirrhotic patients had increased cerebrospinal fluid specific gravity (CSF-SG) compared to healthy controls (+0.4 %, p < 0.0001). Cirrhotic patients with ACLF have decreased CSF-SG as compared to cirrhotic patients without ACLF (-0.2 %, p = 0.0030) that remained higher than in healthy controls. The presence of hepatic encephalopathy did not modify CSF-SG (-0.09 %, p = 0.1757). Specific gravity did not differ between different brain regions according to the presence or absence of either ACLF or HE. In patients with acute decompensation of cirrhosis, and those with ACLF, CSF specific gravity is modified compared to

  13. Using the Minimally Invasive Impella 5.0 via the Right Subclavian Artery Cutdown for Acute on Chronic Decompensated Heart Failure as a Bridge to Decision

    PubMed Central

    Bansal, Aditya; Bhama, Jay K.; Patel, Rajan; Desai, Sapna; Mandras, Stacy A.; Patel, Hamang; Collins, Tyrone; Reilly, John P.; Ventura, Hector O.; Parrino, P. Eugene

    2016-01-01

    Background: Outcomes of traditional mechanical support paradigms (extracorporeal membrane oxygenation, intraaortic balloon pump [IABP], and permanent left ventricular assist device [LVAD]) in acute decompensated heart failure have generally been suboptimal. Novel approaches, such as minimally invasive LVAD therapy (Impella 5.0 device), promise less invasive but equivalent hemodynamic support. However, it is yet unknown whether the outcomes with such devices support widespread acceptance of this new technology. We recently started utilizing the right subclavian artery (RSA) for Impella 5.0 implantation and report our early experience and outcomes with this novel approach. Methods: A single-center retrospective review was performed of 24 patients with acute on chronic decompensated heart failure who received the Impella 5.0 via the RSA from June 2011 to May 2014. The device was implanted via a cutdown through an 8-mm vascular graft sewn to the RSA. The device was positioned with fluoroscopy and transesophageal echocardiography. Results: The mean age of the patients was 51.29 years, and 75% were male. At implantation, all patients were mechanically ventilated on at least 2 inotropes with persistent cardiogenic shock, and 17 (70.8%) were on IABP support. Postimplantation, 21 (87.5%) tolerated extubation, and all 17 of the patients with IABPs tolerated discontinuation of IABP support. The reduction in the Model for End-Stage Liver Disease score preimplantation vs postimplantation was statistically significant (21.17 vs 14.88, P=0.0014), suggesting improvement in end organ function. A significant decrease was also seen in creatinine levels before and after implantation (2.17 mg/dL vs 1.50 mg/dL, P=0.0043). The endpoint of support included recovery in 6 patients (25.0%), permanent LVAD in 9 (37.5%), and heart transplantation in 2 (8.3%). Death occurred in 7 patients (29.2%) as a result of multisystem organ failure, infection, or patient withdrawal of care. Conclusion

  14. Hyperkalemia after acute metabolic decompensation in two children with vitamin B12-unresponsive methylmalonic acidemia and normal renal function.

    PubMed

    Pela, I; Gasperini, S; Pasquini, E; Donati, M A

    2006-07-01

    The patients affected by vitamin B12-unresponsive methylmalonic acidemia (MMA) on the long run develop chronic renal disease with interstitial nephropathy and progressive renal insufficiency. The mechanism of nephrotoxicity in vitamin B12-unresponsive MMA is not yet known. Chronic hyporeninemic hypoaldosteronism has been found in many cases of methylmalonic acidemia, hyperkalemia and renal tubular acidosis type 4. We report 2 patients affected by B12-unresponsive methylmalonic acidemia diagnosed at the age of 23 months and 5 years, respectively, with normal glomerular filtration and function. They showed hyporeninemic hypoaldosteronism and significant hyperkalemia requiring sodium potassium exchange resin (Kayexalate) therapy after an episode of metabolic decompensation leading to diagnosis of MMA. In both children, hyporeninemic hypoaldosteronism and hyperkalemia disappeared after 6 months of good metabolic control.

  15. In-hospital brain natriuretic peptide and N-terminal prohormone brain natriuretic peptide variations are predictors of short-term and long-term outcome in acute decompensated heart failure

    PubMed Central

    2011-01-01

    Acute decompensated heart failure is one of the most important causes of hospitalisation worldwide. Natriuretic peptides have shown their usefulness in the diagnosis and management of heart failure. Their variations during hospitalisation also appear useful to predict outcomes. In particular, data from the literature demonstrate that reduction from admission to discharge of brain natriuretic peptide and N-terminal prohormone brain natriuretic peptide in these patients is a predictor of future cardiovascular events. PMID:21345261

  16. A case of marked diuresis by combined dopamine and atrial natriuretic peptide administration without renal injury in acute decompensated heart failure.

    PubMed

    Kamiya, Masataka; Sato, Naoki; Akiya, Mai; Okazaki, Hirotake; Takahashi, Yasuhiro; Mizuno, Kyoichi

    2013-01-01

    Renal injury is an important factor for worsening outcome in acute decompensated heart failure (ADHF). An 81-year-old woman was admitted due to ADHF with dyspnea and mild peripheral edema. The patient was managed with intravenous administration of atrial natriuretic peptide (ANP) at a dose of 0.0125 μg/kg/minute, which did not control volume overload even at an increased dose of 0.025 μg/kg/minute. After a low dose of dopamine (DA) of 1.0 μg/kg/ minute was added, urine output increased markedly to 120 from 30 mL/hour. Furthermore, her heart rate decreased to 80-100 from 120 bpm and the congestion improved with a reduced brain natriuretic peptide level. Interestingly, the combination of ANP and DA therapy reduced serum creatinine as well as the levels of urinary liver-type fatty acid binding protein, a novel reno-tubular stress marker, by 98.9%, and an oxidative stress marker, urinary 8-hydroxydeoxyguanosine, by 88.2% from baseline levels. Thus, this ADHF patient, a nonresponder to ANP alone, improved without renal injury when administered combination therapy consisting of low doses of ANP and DA, suggesting that this combined therapy might be useful for better management of ADHF in patients without diuretic responses with ANP alone. Further prospective studies are warranted.

  17. Relief and Recurrence of Congestion During and After Hospitalization for Acute Heart Failure: Insights from DOSE-AHF and CARRESS-HF

    PubMed Central

    Lala, Anuradha; McNulty, Steven E.; Mentz, Robert J.; Dunlay, Shannon; Vader, Justin M.; AbouEzzeddine, Omar F.; DeVore, Adam D.; Khazanie, Prateeti; Redfield, Margaret M.; Goldsmith, Steven R.; Bart, Bradley A.; Anstrom, Kevin J.; Felker, Michael; Hernandez, Adrian F.; Stevenson, Lynne W.

    2015-01-01

    Background Congestion is the most frequent cause for hospitalization in acute decompensated heart failure (ADHF). Although decongestion is a major goal of acute therapy, it is unclear how the clinical components of congestion (e.g., peripheral edema, orthopnea) contribute to outcomes after discharge or how well decongestion is maintained. Methods and Results A post-hoc analysis was performed of 496 patients enrolled in the DOSE-AHF and CARRESS-HF trials during hospitalization with ADHF and clinical congestion. A simple “orthodema” congestion score was generated based on symptoms of orthopnea (≥2 pillows=2 points, <2 pillows=0 points) and peripheral edema (trace=0 points, moderate=1 point, severe=2 points) at baseline, discharge, and 60-day follow-up. Orthodema scores were classified as absent (score of 0), low-grade (score of 1–2), and high-grade (score of 3–4), and the association with death, rehospitalization or unscheduled medical visits through 60 days was assessed. At baseline, 65% of patients had high-grade orthodema and 35% had low-grade orthodema. At discharge, 52% patients were free from orthodema at discharge (score = 0) and these patients had lower 60-day rates of death, rehospitalization, or unscheduled visits (50%) compared to those with low-grade or high-grade orthodema (52% and 68%, respectively, p=0.038). Of the patients without orthodema at discharge, 27% relapsed to low-grade orthodema and 38% to high-grade orthodema at 60-day follow-up. Conclusions Increased severity of congestion by a simple orthodema assessment is associated with increased morbidity and mortality. Despite intent to relieve congestion, current therapy often fails to relieve orthodema during hospitalization or to prevent recurrence after discharge. Clinical Trial Registration URL: http://www.clinicaltrials.gov. Unique identifiers: NCT00608491, NCT00577135. PMID:26041600

  18. Serial measurement of NT-proBNP predicts adverse cardiovascular outcome in children with primary myocardial dysfunction and acute decompensated heart failure (ADHF)

    PubMed Central

    Medar, Shivanand; Hsu, Daphne T.; Ushay, H. Michael; Lamour, Jacqueline M.; Cohen, Hillel W; Killinger, James S.

    2015-01-01

    Introduction In children, elevated amino terminal pro B-type naturetic peptide (NT-proBNP) levels are associated with impaired heart function. The predictive value of serial monitoring of NT-proBNP levels in acute decompensated heart failure (ADHF) is unclear. Methods This prospective observational study enrolled patients ≤ 21 years with primary myocardial dysfunction and ADHF. NT-proBNP levels were obtained on enrollment (D0), day 2 (D2) and day 7 (D7). Clinical, laboratory and imaging data were collected on enrollment. CV outcome was defined as Heart Transplant (HTx), Ventricular Assist Device (VAD) placement, Extracorporeal Membrane Oxygenation or death at 1 year after admission. NT-proBNP levels and the percent change from D0 to D2 and D0 to D7 were calculated and compared between those with and without adverse cardiovascular (ACV) outcome. Results Sixteen consecutive patients were enrolled. ACV outcome occurred in 6 (37.5%, 4 HTx and 2 VAD). In patients with an ACV outcome, median NT-ProBNP levels at D7 were significantly higher (7,365 Vs. 1,196 pg/ml; p= 0.02) and the percent decline in NT-proBNP was significantly smaller (28% vs. 73%, p=0.02) compared to those without an ACV outcome. ROC curve analysis revealed that a less than 55% decline in NT-proBNP levels at D7 had a sensitivity and specificity of 83% and 90% respectively in predicting an ACV [AUC 0.86, CI (0.68,1.0), p=0.02]. Conclusions In conclusion, children with primary myocardial dysfunction and ADHF, a persistently elevated NT-proBNP and/or a lesser degree of decline in NT-proBNP during the first week of presentation were strongly associated with ACV outcome. Serial NT-proBNP monitoring may allow the early identification of children at risk for worse outcome. PMID:25856472

  19. Decompensation of chronic stable alcoholic liver disease by severe exfoliative dermatitis.

    PubMed

    Shawcross, Debbie L; Mookerjee, Rajeshwar P; Jalan, Rajiv

    2003-04-01

    Of the numerous precipitants of hepatic decompensation in chronic liver disease, there are no reports in the literature documenting an acute decompensation following an acute episode of severe dermatitis. This case highlights the haemodynamic consequences of a severe flare up of exfoliative dermatitis in a patient with stable chronic alcoholic liver disease, speculates on the mechanism by which this may provoke clinical decompensation and the impact this may have upon liver failure.

  20. Decompensated heart failure

    PubMed Central

    Mangini, Sandrigo; Pires, Philippe Vieira; Braga, Fabiana Goulart Marcondes; Bacal, Fernando

    2013-01-01

    ABSTRACT Heart failure is a disease with high incidence and prevalence in the population. The costs with hospitalization for decompensated heart failure reach approximately 60% of the total cost with heart failure treatment, and mortality during hospitalization varies according to the studied population, and could achieve values of 10%. In patients with decompensated heart failure, history and physical examination are of great value for the diagnosis of the syndrome, and also can help the physician to identify the beginning of symptoms, and give information about etiology, causes and prognosis of the disease. The initial objective of decompensated heart failure treatment is the hemodynamic and symptomatic improvement preservation and/or improvement of renal function, prevention of myocardial damage, modulation of the neurohormonal and/or inflammatory activation and control of comorbidities that can cause or contribute to progression of the syndrome. According to the clinical-hemodynamic profile, it is possible to establish a rational for the treatment of decompensated heart failure, individualizing the proceedings to be held, leading to reduction in the period of hospitalization and consequently reducing overall mortality. PMID:24136770

  1. The Usefulness of the Delta Neutrophil Index for Predicting Superimposed Pneumonia in Patients with Acute Decompensated Heart Failure in the Emergency Department

    PubMed Central

    Lee, Jong Wook; Kwon, Woocheol; Lee, Seok Jeong; Kang, Kyung Sik; Kim, Hyung Il; Kim, Oh Hyun; Cha, Kyoung-Chul; Kim, Hyun; Hwang, Sung Oh

    2016-01-01

    Background Although respiratory infections, such as pneumonia, have long been recognized as precipitators of exacerbation in patients with acute decompensated heart failure (ADHF), identifying signs of concomitant pneumonia in ADHF is a clinical diagnostic challenge. We evaluated the predictive value of the delta neutrophil index (DNI), a new indicator for immature granulocytes, for diagnosing superimposed pneumonia in patients presenting with ADHF in the emergency department (ED). Methods This was a retrospective and observational study of consecutive patients (>18 years old) diagnosed with an ADHF in the ED over a 7-month period. Patients were categorized into either the ADHF group or the ADHF with pneumonia group. DNI, serum white blood cell (WBC), C-reactive protein (CRP), and β-natriuretic peptide (BNP) were measured upon ED arrival. Results The ADHF with pneumonia group included 30 patients (20.4%). Median initial DNI, WBC, and CRP were significantly higher in the ADHF with pneumonia group [0% vs. 1.8%, p<0.001, 8,200 cells/mL vs. 10,470 cells/mL, p<0.001, and 0.56 mg/dL vs. 6.10 mg/dL, p<0.001]. Multiple logistic regression analyses showed that only initial DNI significantly predicted the presence of superimposed pneumonia in patients with ADHF. In the receiver operating characteristic curves for initial DNI, WBC, and CRP for differentiating superimposed pneumonia in ADHF patients, the area under curve (AUC) of DNI (0.916 [95% confidence interval 0.859–0.955]) was good. AUC of DNI was significantly higher than AUC of CRP and WBC [0.828 and 0.715] (DNI vs. CRP, p = 0.047 and DNI vs. WBC, p<0.001). Conclusions Initial DNI, which was measured upon ED arrival, was significantly higher in the ADHF with pneumonia group than in the ADHF group. The initial DNI’s ability of prediction for ADHF with superimposed pneumonia in the ED was good and it was better than those of serum WBC and CRP. Therefore, DNI may serve as a convenient and useful marker for early

  2. Renal neurohormonal regulation in heart failure decompensation.

    PubMed

    Jönsson, Sofia; Agic, Mediha Becirovic; Narfström, Fredrik; Melville, Jacqueline M; Hultström, Michael

    2014-09-01

    Decompensation in heart failure occurs when the heart fails to balance venous return with cardiac output, leading to fluid congestion and contributing to mortality. Decompensated heart failure can cause acute kidney injury (AKI), which further increases mortality. Heart failure activates signaling systems that are deleterious to kidneys such as renal sympathetic nerve activity (RSNA), renin-angiotensin-aldosterone system, and vasopressin secretion. All three reduce renal blood flow (RBF) and increase tubular sodium reabsorption, which may increase renal oxygen consumption causing AKI through renal tissue hypoxia. Vasopressin contributes to venous congestion through aquaporin-mediated water retention. Additional water retention may be mediated through vasopressin-induced medullary urea transport and hyaluronan but needs further study. In addition, there are several systems that could protect the kidneys and reduce fluid retention such as natriuretic peptides, prostaglandins, and nitric oxide. However, the effect of natriuretic peptides and nitric oxide are blunted in decompensation, partly due to oxidative stress. This review considers how neurohormonal signaling in heart failure drives fluid retention by the kidneys and thus exacerbates decompensation. It further identifies areas where there is limited data, such as signaling systems 20-HETE, purines, endothelin, the role of renal water retention mechanisms for congestion, and renal hypoxia in AKI during heart failure.

  3. Effects of Hyponatremia Normalization on the Short-Term Mortality and Rehospitalizations in Patients with Recent Acute Decompensated Heart Failure: A Retrospective Study.

    PubMed

    De Vecchis, Renato; Di Maio, Marco; Di Biase, Giuseppina; Ariano, Carmelina

    2016-10-22

    Background: Several studies have shown that hyponatremia is associated with increased risk of rehospitalization and death in patients with heart failure. In these studies, chronic heart failure (CHF) patients with persistent hyponatremia were compared only with CHF patients with a normal sodium level at hospital admission. Aims: In the present retrospective study, conducted in a cohort of patients with recent acute decompensated heart failure (ADHF), all with hyponatremia ascertained at the time of hospital admission, we aimed to evaluate the effect of the normalization of serum sodium on the composite endpoint of short-term rehospitalization and mortality. Methods: A retrospective study centered on medical records of patients hospitalized for ADHF in the period April 2013 to April 2016 was performed. Data regarding serum sodium measurements had to be collected from medical records of cardiology wards of two hospitals, and were then processed for statistical analysis. As an inclusion criterion for enrollment, patients had to be suffering from heart failure that had required at least one hospitalization. Moreover, they had to be suffering from a state of hyponatremia (serum sodium < 135 mEq/L) at admission on the occasion of the index hospitalization. Patients with hyponatremia at admission were divided into two groups, one comprising patients with hyponatremia that persisted at the time of discharge (persistent hyponatremia) and a second including patients who had achieved normalization of their serum sodium levels (serum Na⁺ ≥ 135 mEq/L) during hospitalization until discharge. For both groups, the risk of mortality and rehospitalization during a 30-day follow-up was assessed. Results: One hundred and sixty CHF patients with various degrees of functional impairment were enrolled in the study. Among them, 56 (35%) had persistent hyponatremia over the course of hospitalization. At multivariable Cox proportional-hazards regression analysis, the risk of having a 30

  4. Effects of Hyponatremia Normalization on the Short-Term Mortality and Rehospitalizations in Patients with Recent Acute Decompensated Heart Failure: A Retrospective Study

    PubMed Central

    De Vecchis, Renato; Di Maio, Marco; Di Biase, Giuseppina; Ariano, Carmelina

    2016-01-01

    Background: Several studies have shown that hyponatremia is associated with increased risk of rehospitalization and death in patients with heart failure. In these studies, chronic heart failure (CHF) patients with persistent hyponatremia were compared only with CHF patients with a normal sodium level at hospital admission. Aims: In the present retrospective study, conducted in a cohort of patients with recent acute decompensated heart failure (ADHF), all with hyponatremia ascertained at the time of hospital admission, we aimed to evaluate the effect of the normalization of serum sodium on the composite endpoint of short-term rehospitalization and mortality. Methods: A retrospective study centered on medical records of patients hospitalized for ADHF in the period April 2013 to April 2016 was performed. Data regarding serum sodium measurements had to be collected from medical records of cardiology wards of two hospitals, and were then processed for statistical analysis. As an inclusion criterion for enrollment, patients had to be suffering from heart failure that had required at least one hospitalization. Moreover, they had to be suffering from a state of hyponatremia (serum sodium < 135 mEq/L) at admission on the occasion of the index hospitalization. Patients with hyponatremia at admission were divided into two groups, one comprising patients with hyponatremia that persisted at the time of discharge (persistent hyponatremia) and a second including patients who had achieved normalization of their serum sodium levels (serum Na+ ≥ 135 mEq/L) during hospitalization until discharge. For both groups, the risk of mortality and rehospitalization during a 30-day follow-up was assessed. Results: One hundred and sixty CHF patients with various degrees of functional impairment were enrolled in the study. Among them, 56 (35%) had persistent hyponatremia over the course of hospitalization. At multivariable Cox proportional-hazards regression analysis, the risk of having a 30

  5. Prednisone lowers serum uric acid levels in patients with decompensated heart failure by increasing renal uric acid clearance.

    PubMed

    Liu, Chao; Zhen, Yuzhi; Zhao, Qingzhen; Zhai, Jian-Long; Liu, Kunshen; Zhang, Jian-Xin

    2016-07-01

    Clinical studies have shown that large doses of prednisone could lower serum uric acid (SUA) in patients with decompensated heart failure (HF); however, the optimal dose of prednisone and underlying mechanisms are unknown. Thirty-eight patients with decompensated HF were randomized to receive standard HF care alone (n = 10) or with low-dose (15 mg/day, n = 8), medium-dose (30 mg/day, n = 10), or high-dose prednisone (60 mg/day, n = 10), for 10 days. At the end of the study, only high-dose prednisone significantly reduced SUA, whereas low- and medium-dose prednisone and standard HF care had no effect on SUA. The reduction in SUA in high-dose prednisone groups was associated with a significant increase in renal uric acid clearance. In conclusion, prednisone can reduce SUA levels by increasing renal uric acid clearance in patients with decompensated HF.

  6. Management options in decompensated cirrhosis.

    PubMed

    Shah, Neeral L; Banaei, Yasmin Pourkazemi; Hojnowski, Kristen L; Cornella, Scott L

    2015-01-01

    Chronic injury to the liver from a variety of different sources can result in irreversible scarring of the liver, known as cirrhosis. Cirrhosis is a major cause of morbidity and mortality in the USA, and according to the Centers for Disease Control and Prevention was responsible for 31,903 deaths in 2010 alone. It is thus of the utmost importance to appropriately manage these patients in the inpatient and outpatient setting to improve morbidity and mortality. In this review, we address four major areas of cirrhosis management: outpatient management of portal hypertension with decompensation, hepatic encephalopathy, hepatorenal syndrome, and bleeding/coagulation issues. Outpatient management covers recommendations for health care maintenance and screening. Hepatic encephalopathy encompasses a brief review of pathophysiology, treatment in the acute setting, and long-term prevention. Hepatorenal syndrome is discussed in regards to pathophysiology and treatment in the hospital setting. Finally, a discussion of the assessment of coagulation profiles in cirrhosis and recommendations for bleeding and thrombosis complications is included. These topics are not all encompassing with regard to this complicated population, but rather an overview of a few medical problems that are commonly encountered in their care.

  7. [Complementary treatment of acute heart failure in patients with diabetes, chronic obstructive pulmonary disease or anemia].

    PubMed

    Carrasco Sánchez, Francisco Javier; Recio Iglesias, Jesús; Grau Amorós, Jordi

    2014-03-01

    Diabetes, chronic obstructive pulmonary disease (COPD) and anemia are comorbidities with a high prevalence and impact in heart failure (HF). The presence of these comorbidities considerably worsens the prognosis of HF. Diabetic patients have a higher likelihood of developing symptoms of HF and both the treatment of diabetes and that of acute HF are altered by the coexistence of both entities. The glycemic targets in patients with acute HF are not well-defined, but could show a U-shaped relationship. Stress hyperglycemia in non-diabetic patients with HF could also have a deleterious effect on the medium-term prognosis. The inter-relationship between COPD and HF hampers diagnosis due to the overlap between the symptoms and signs of both entities and complementary investigations. The treatment of acute HF is also altered by the presence of COPD. Anemia is highly prevalent and is often the direct cause of decompensated HF, the most common cause being iron deficiency anemia. Iron replacement therapy, specifically intravenous forms, has helped to improve the prognosis of acute HF.

  8. Early Indication of Decompensated Heart Failure in Patients on Home-Telemonitoring: A Comparison of Prediction Algorithms Based on Daily Weight and Noninvasive Transthoracic Bio-impedance

    PubMed Central

    Bonomi, Alberto G; Goode, Kevin M; Reiter, Harald; Habetha, Joerg; Amft, Oliver; Cleland, John GF

    2016-01-01

    Background Heart Failure (HF) is a common reason for hospitalization. Admissions might be prevented by early detection of and intervention for decompensation. Conventionally, changes in weight, a possible measure of fluid accumulation, have been used to detect deterioration. Transthoracic impedance may be a more sensitive and accurate measure of fluid accumulation. Objective In this study, we review previously proposed predictive algorithms using body weight and noninvasive transthoracic bio-impedance (NITTI) to predict HF decompensations. Methods We monitored 91 patients with chronic HF for an average of 10 months using a weight scale and a wearable bio-impedance vest. Three algorithms were tested using either simple rule-of-thumb differences (RoT), moving averages (MACD), or cumulative sums (CUSUM). Results Algorithms using NITTI in the 2 weeks preceding decompensation predicted events (P<.001); however, using weight alone did not. Cross-validation showed that NITTI improved sensitivity of all algorithms tested and that trend algorithms provided the best performance for either measurement (Weight-MACD: 33%, NITTI-CUSUM: 60%) in contrast to the simpler rules-of-thumb (Weight-RoT: 20%, NITTI-RoT: 33%) as proposed in HF guidelines. Conclusions NITTI measurements decrease before decompensations, and combined with trend algorithms, improve the detection of HF decompensation over current guideline rules; however, many alerts are not associated with clinically overt decompensation. PMID:26892844

  9. Metabolic decompensation in methylmalonic aciduria: which biochemical parameters are discriminative?

    PubMed

    Zwickler, Tamaris; Haege, Gisela; Riderer, Alina; Hörster, Friederike; Hoffmann, Georg F; Burgard, Peter; Kölker, Stefan

    2012-09-01

    Recurrent, life-threatening metabolic decompensations often occur in patients with methylmalonic aciduria (MMAuria). Our study evaluated (impending) metabolic decompensations in these patients aiming to identify the most frequent and reliable clinical and biochemical abnormalities that could be helpful for decision-making on when to start an emergency treatment. Seventy-six unscheduled and 179 regular visits of 10 patients with confirmed MMAuria continuously followed by our metabolic centre between 1975 and 2009 were analysed. The most frequent symptom of an impending acute metabolic decompensation was vomiting (90% of episodes), whereas symptoms of intercurrent infectious disease (29%) or other symptoms (such as food refusal and impaired consciousness) were found less often. Thirty-five biochemical parameters were included in the analysis. Among them, pathological changes of acid-base balance reflecting metabolic acidosis with partial respiratory compensation (decreased pH, pCO(2), standard bicarbonate, and base excess) and elevated ammonia were the most reliable biochemical parameters for the identification of a metabolic decompensation and the estimation of its severity. In contrast, analyses of organic acids, acylcarnitines and carnitine status were less discriminative. In conclusion, careful history taking and identification of suspicious symptoms in combination with a small number of rapidly available biochemical parameters are helpful to differentiate compensated metabolic condition and (impending) metabolic crisis and to decide when to start an emergency treatment.

  10. Management of coagulopathy in patients with decompensated liver cirrhosis.

    PubMed

    Amarapurkar, Pooja D; Amarapurkar, Deepak N

    2011-01-01

    Patients with decompensated liver cirrhosis have significantly impaired synthetic function. Many proteins involved in the coagulation process are synthesized in the liver. Routinely performed tests of the coagulation are abnormal in patients with decompensated liver cirrhosis. This has led to the widespread belief that decompensated liver cirrhosis is prototype of acquired hemorrhagic coagulopathy. If prothrombin time is prolonged more than 3 seconds over control, invasive procedures like liver biopsy, splenoportogram, percutaneous cholangiography, or surgery were associated with increased risk of bleeding, and coagulopathy should be corrected with infusion of fresh frozen plasma. These practices were without any scientific evidence and were associated with significant hazards of fresh frozen plasma transfusion. Now, it is realized that coagulation is a complex process involving the interaction of procoagulation and anticoagulation factors and the fibrinolytic system. As there is reduction in both anti and procoagulant factors, global tests of coagulation are normal in patients with acute and chronic liver disease indicating that coagulopathy in liver disease is more of a myth than a reality. In the last few years, surgical techniques have substantially improved, and complex procedures like liver transplantation can be done without the use of blood or blood products. Patients with liver cirrhosis may also be at increased risk of thrombosis. In this paper, we will discuss coagulopathy, increased risk of thrombosis, and their management in decompensated liver cirrhosis.

  11. Management of patients with decompensated cirrhosis.

    PubMed

    Harrison, Phillip M

    2015-04-01

    During the assessment of a patient with liver disease, finding the patient has decompensated cirrhosis, as defined by the presence of jaundice, ascites, variceal haemorrhage or hepatic encephalopathy, has major implications regarding management and prevention of cirrhosis-related complications, as well as consideration for a referral for liver transplantation evaluation. Prognosis is markedly worse in patients with decompensated compared with compensated cirrhosis. In general, any patient with decompensated cirrhosis should receive evaluation and medical care by a hepatologist. Since patients frequently present with more than one facet of liver decompensation, such cases pose a complex management challenge requiring input from a multidisciplinary team and close liaison with a liver transplant centre.

  12. Current and Future Percutaneous Strategies for the Treatment of Acute and Chronic Heart Failure.

    PubMed

    Amat-Santos, Ignacio J; Varela-Falcón, Luis H; Abraham, William T

    2017-01-30

    The prevalence of heart failure (HF) has risen in parallel with improved survival in patients after a myocardial infarction and an aging population worldwide. In recent years, new percutaneous therapies have been developed to complement current established treatments for acute/decompensated and chronic HF and minimize risks. In acute presentations, the failure of medical treatment is no longer the end of the road in refractory circulatory shock; the use of mechanical circulatory support devices may be the next milestone in well-resourced health settings. Although evidence in this area is difficult to generate, research networks can facilitate the volume and quality of data needed to further augment the clinician's knowledge. Pulsatile (intra-aortic balloon pump), axial continuous (Impella), or centrifugal continuous pumps (TandemHeart; HeartMate PHP) together with percutaneously implanted extracorporeal membrane oxygenation are radically changing the prognosis of acute HF. Newer percutaneous therapies for chronic HF are based on attractive hypotheses, including left atrial decompression with shunting devices, left ventricle restoration through partitioning devices, or pressure-guided implantable therapies that may help to promptly treat decompensations. To date, only the last has been proved effective in a randomized study. Therefore, thorough research is still needed in this dynamic and promising field.

  13. Predictors of early dyspnoea relief in acute heart failure and the association with 30-day outcomes: findings from ASCEND-HF

    PubMed Central

    Mentz, Robert J.; Hernandez, Adrian F.; Stebbins, Amanda; Ezekowitz, Justin A.; Felker, G. Michael; Heizer, Gretchen M.; Atar, Dan; Teerlink, John R.; Califf, Robert M.; Massie, Barry M.; Hasselblad, Vic; Starling, Randall C.; O'Connor, Christopher M.; Ponikowski, Piotr

    2013-01-01

    Aims To examine the characteristics associated with early dyspnoea relief during acute heart failure (HF) hospitalization, and its association with 30-day outcomes. Methods and results ASCEND-HF was a randomized trial of nesiritide vs. placebo in 7141 patients hospitalized with acute HF in which dyspnoea relief at 6 h was measured on a 7-point Likert scale. Patients were classified as having early dyspnoea relief if they experienced moderate or marked dyspnoea improvement at 6 h. We analysed the clinical characteristics, geographical variation, and outcomes (mortality, mortality/HF hospitalization, and mortality/hospitalization at 30 days) associated with early dyspnoea relief. Early dyspnoea relief occurred in 2984 patients (43%). In multivariable analyses, predictors of dyspnoea relief included older age and oedema on chest radiograph; higher systolic blood pressure, respiratory rate, and natriuretic peptide level; and lower serum blood urea nitrogen (BUN), sodium, and haemoglobin (model mean C index = 0.590). Dyspnoea relief varied markedly across countries, with patients enrolled from Central Europe having the lowest risk-adjusted likelihood of improvement. Early dyspnoea relief was associated with lower risk-adjusted 30-day mortality/HF hospitalization [hazard ratio (HR) 0.81; 95% confidence interval (CI) 0.68–0.96] and mortality/hospitalization (HR 0.85; 95% CI 0.74–0.99), but similar mortality. Conclusion Clinical characteristics such as respiratory rate, pulmonary oedema, renal function, and natriuretic peptide levels are associated with early dyspnoea relief, and moderate or marked improvement in dyspnoea was associated with a lower risk for 30-day outcomes. PMID:23159547

  14. Sleep-disordered breathing in patients with decompensated heart failure

    PubMed Central

    Valdivia-Arenas, Martin A.; Powers, Michael

    2009-01-01

    Sleep-disordered breathing (SDB) has a higher prevalence in patients with heart failure than in the general middle-aged population. Obstructive sleep apnea (OSA), one of the forms of SBD, promotes poorly controlled hypertension, coronary events, and atrial fibrillation events that can lead to acutely decompensated heart failure (ADHF), and evidence suggests that untreated OSA increases mortality in patients with heart failure. Cheyne–Stokes respiration and central sleep apnea (CSA) have long been associated with heart failure and, in many patients, can coexist with OSA. In this article, we propose a systematic approach to diagnose and treat OSA in patients with ADHF based on current evidence. PMID:18758944

  15. Elevated troponin T on discharge predicts poor outcome of decompensated heart failure.

    PubMed

    Koide, Kimi; Yoshikawa, Tsutomu; Nagatomo, Yuji; Kohsaka, Shun; Anzai, Toshihisa; Meguro, Tomomi; Ogawa, Satoshi

    2010-05-01

    Persistent elevation of cardiac troponin T (cTnT) predicts an adverse clinical outcome in patients with chronic heart failure (HF), but the underlying mechanisms remain to be determined. We investigated the association between predischarge cTnT elevation and coexistent pathophysiology in patients with decompensated HF. Plasma cTnT levels were determined before discharge in 170 patients with decompensated HF. We divided the patients into a group that was positive for cTnT [cTnT(+) group, n = 40] and a group that was negative for cTnT [cTnT(-) group, n = 130]. Multivariate analysis showed that use of beta-blocker therapy (odds ratio [OR] = 0.236, P = 0.003), an elevated high-sensitivity C-reactive protein (hsCRP) level (OR = 3.731, P = 0.006), a high brain natriuretic peptide (BNP) level (OR = 3.570, P = 0.007), diabetes (OR = 3.090, P = 0.018), and anemia (OR = 2.330, P = 0.047) were independently associated with cTnT positivity. During a mean follow-up period of 441 days after discharge, total mortality (P < 0.001), cardiac death (P < 0.001), and exacerbation of HF requiring hospitalization (P = 0.007) were all more common in the cTnT(+) group than in the cTnT(-) group. Cox proportional hazards analysis showed that cTnT positivity was an independent predictor of total mortality (hazard ratio = 5.008, P = 0.004) in an age- and gender-matched model. Elevation of cTnT during convalescence was associated with lack of beta-blocker therapy, a high hsCRP level at discharge, a high BNP level at discharge, diabetes, and anemia, and a worse clinical outcome in patients with decompensated HF.

  16. Role of Soluble ST2 as a Prognostic Marker in Patients with Acute Heart Failure and Renal Insufficiency.

    PubMed

    Kim, Min-Seok; Jeong, Tae-Dong; Han, Seung-Bong; Min, Won-Ki; Kim, Jae-Joong

    2015-05-01

    This study sought to assess the relationship between serum concentrations of the soluble ST2 (sST2) and B-type natriuretic peptide (BNP) and investigate the role of sST2 as a prognosticator in patients hospitalized with acute heart failure (HF) and renal insufficiency. sST2 was measured at admission and discharge in 66 patients hospitalized with acute decompensated HF and renal insufficiency (estimated glomerular filtration rate [eGFR] < 90 mL/min/1.73 m(2)) using a high sensitivity immunoassay. BNP was sampled at the same time and compared to sST2. Demographical, biochemical, and echocardiographic data were also obtained during hospitalization.There were positive correlations between sST2 and BNP levels at admission (r = 0.330, P = 0.007) and at discharge (r = 0.320, P = 0.009) in overall patients. However, there was no correlation between them at each timepoint in patients with severe renal insufficiency (eGFR < 30 mL/min/1.73 m(2), n = 17). sST2 level was not changed with the degree of renal function, even though BNP level was much higher in patients with severe renal insufficiency. During 3 month follow-up, 9 (13.6%) died and 16 (24.2%) were readmitted due to HF aggravation.On multivariate analysis, sST2 at discharge was independently associated with death or HF readmission during 3 months after discharge (hazard ratio, 1.038; 95% confidence interval, 1.011-1.066, P = 0.006). In conclusion, sST2 is not affected by renal function compared with BNP in acute HF patients. The measurement of predischarge sST2 can be helpful in predicting short-term outcomes in acute decompensated HF patients with renal insufficiency.

  17. Challenges in comparing the acute cognitive outcomes of high-frequency repetitive transcranial magnetic stimulation (HF-rTMS) vs. electroconvulsive therapy (ECT) in major depression: A systematic review.

    PubMed

    Kedzior, Karina Karolina; Schuchinsky, Maria; Gerkensmeier, Imke; Loo, Colleen

    2017-03-02

    The present study aimed to systematically compare the cognitive outcomes of high-frequency repetitive transcranial magnetic stimulation (HF-rTMS) and electroconvulsive therapy (ECT) in head-to-head studies with major depression (MDD) patients. A systematic literature search identified six studies with 219 MDD patients that were too heterogeneous to reliably detect meaningful differences in acute cognitive outcomes after ECT vs. HF-rTMS. Cognitive effects of brain stimulation vary depending on the timeframe and methods of assessment, stimulation parameters, and maintenance treatment. Thus, acute and longer-term differences in cognitive outcomes both need to be investigated at precisely defined timeframes and with similar instruments assessing comparable functions.

  18. [Signs and symptoms in patients with decompensated heart failure: inference of priority nursing diagnoses].

    PubMed

    Aliti, Graziella Badin; Linhares, Joelza Celesilvia Chisté; Linch, Graciele Fernanda da Costa; Ruschel, Karen Brasil; Rabelo, Eneida Rejane

    2011-09-01

    The aim of this study is to identify the signs and symptoms of patients admitted for decompensated heart failure (HF) in order to infer the priority nursing diagnoses (ND). This is a cross-sectional study undertaken in a university hospital. The data were collected by nurses trained to deal with HF and registered in a file containing identification items, and demographic and clinical variables. We included 303 patients. Most patients were in emergency departments (95.7%) with functional class III (65.7%). The signs and symptoms identified at the time of admission were dyspnea (91.4%), paroxysmal nocturnal dyspnea (87.5%), fatigue (67.3%), edema (63.7%), orthopnea (55.4 %) and jugular vein distention (28.7%). From the signs and symptoms raised, that became the set of relevant clues and consistent as an indicator for ND, we conclude that Decreased Cardiac Output and Fluid Volume Excess diagnoses were the priorities for this population.

  19. Rationale and methods of the multicenter randomised trial of a heart failure management programme among geriatric patients (HF-Geriatrics)

    PubMed Central

    2011-01-01

    Background Disease management programmes (DMPs) have been shown to reduce hospital readmissions and mortality in adults with heart failure (HF), but their effectiveness in elderly patients or in those with major comorbidity is unknown. The Multicenter Randomised Trial of a Heart Failure Management Programme among Geriatric Patients (HF-Geriatrics) assesses the effectiveness of a DMP in elderly patients with HF and major comorbidity. Methods/Design Clinical trial in 700 patients aged ≥ 75 years admitted with a primary diagnosis of HF in the acute care unit of eight geriatric services in Spain. Each patient should meet at least one of the following comorbidty criteria: Charlson index ≥ 3, dependence in ≥ 2 activities of daily living, treatment with ≥ 5 drugs, active treatment for ≥ 3 diseases, recent emergency hospitalization, severe visual or hearing loss, cognitive impairment, Parkinson's disease, diabetes mellitus, chronic obstructive pulmonary disease (COPD), anaemia, or constitutional syndrome. Half of the patients will be randomly assigned to a 1-year DMP led by a case manager and the other half to usual care. The DMP consists of an educational programme for patients and caregivers on the management of HF, COPD (knowledge of the disease, smoking cessation, immunizations, use of inhaled medication, recognition of exacerbations), diabetes (knowledge of the disease, symptoms of hyperglycaemia and hypoglycaemia, self-adjustment of insulin, foot care) and depression (knowledge of the disease, diagnosis and treatment). It also includes close monitoring of the symptoms of decompensation and optimisation of treatment compliance. The main outcome variables are quality of life, hospital readmissions, and overall mortality during a 12-month follow-up. Discussion The physiological changes, lower life expectancy, comorbidity and low health literacy associated with aging may influence the effectiveness of DMPs in HF. The HF-Geriatrics study will provide direct

  20. Impact of Orthodontic Decompensation on Bone Insertion

    PubMed Central

    Guedes, Fabio Pinto; Capelozza Filho, Leopoldino; Garib, Daniela Gamba; Nary Filho, Hugo; Borgo, Evandro José; Cardoso, Mauricio de Almeida

    2014-01-01

    There has always been concern in determining the relationship between orthodontic tooth movement and the consequent biological costs to the periodontium and tooth root. The possibility of evaluating the tooth and bone morphology by CBCT allows more accurate analysis of qualitative and quantitative aspects of these processes. This paper presents a case report of a 20-year-old male patient with Class III malocclusion and hyperdivergent facial pattern, who was surgically treated. A significant amount of labial movement of mandibular incisors was performed during orthodontic treatment before surgery. CBCT was used for evaluation of buccal and lingual bone plates before and after tooth decompensation. The changes in the bone insertion level of maxillary and mandibular incisors in the present case encourage a reflection on the treatment protocol in individuals with dentoskeletal discrepancies. PMID:25436157

  1. Nesiritide for pulmonary arterial hypertension with decompensated cor pulmonale.

    PubMed

    Kingman, Martha S; Thompson, Brenda S; Newkirk, Trixie; Torres, Fernando

    2005-01-01

    Pulmonary arterial hypertension complicated by decompensated cor pulmonale is a challenging clinical problem with few effective therapeutic options. B-type natriuretic peptide is a pluripotent hormone that promotes diuresis and natriuresis, vasodilates systemic and pulmonary vessels, and reduces circulating levels of endothelin and aldosterone. It may represent a possible therapeutic strategy for decompensated cor pulmonale in the same manner that it is used to treat decompensated left heart failure. The authors report their experience with B-type natriuretic peptide as adjunctive therapy for pulmonary arterial hypertension complicated by decompensated cor pulmonale. A detailed case report is presented followed by the evaluation of a series of 11 cases occurring in eight patients from December 2002 through April 2004.

  2. Northern Territory Heart Failure Initiative–Clinical Audit (NTHFI–CA)–a prospective database on the quality of care and outcomes for acute decompensated heart failure admission in the Northern Territory: study design and rationale

    PubMed Central

    Iyngkaran, Pupalan; Tinsley, Jeff; Smith, David; Haste, Mark; Nadarajan, Kangaharan; Ilton, Marcus; Battersby, Malcolm; Stewart, Simon; Brown, Alex

    2014-01-01

    Introduction Congestive heart failure is a significant cause of morbidity and mortality in Australia. Accurate data for the Northern Territory and Indigenous Australians are not presently available. The economic burden of this chronic cardiovascular disease is felt by all funding bodies and it still remains unclear what impact current measures have on preventing the ongoing disease burden and how much of this filters down to more remote areas. Clear differentials also exist in rural areas including a larger Indigenous community, greater disease burden, differing aetiologies for heart failure as well as service and infrastructure discrepancies. It is becoming increasingly clear that urban solutions will not affect regional outcomes. To understand regional issues relevant to heart failure management, an understanding of the key performance indicators in that setting is critical. Methods and analysis The Northern Territory Heart Failure Initiative—Clinical Audit (NTHFI-CA) is a prospective registry of acute heart failure admissions over a 12-month period across the two main Northern Territory tertiary hospitals. The study collects information across six domains and five dimensions of healthcare. The study aims to set in place an evidenced and reproducible audit system for heart failure and inform the developing heart failure disease management programme. The findings, is believed, will assist the development of solutions to narrow the outcomes divide between remote and urban Australia and between Indigenous and Non-Indigenous Australians, in case they exist. A combination of descriptive statistics and mixed effects modelling will be used to analyse the data. Ethics and dissemination This study has been approved by respective ethics committees of both the admitting institutions. All participants will be provided a written informed consent which will be completed prior to enrolment in the study. The study results will be disseminated through local and international

  3. Design and Rationale of a Randomized Trial of a Care Transition Strategy in Patients With Acute Heart Failure Discharged From the Emergency Department: GUIDED-HF (Get With the Guidelines in Emergency Department Patients With Heart Failure).

    PubMed

    Fermann, Gregory J; Levy, Phillip D; Pang, Peter; Butler, Javed; Ayaz, S Imran; Char, Douglas; Dunn, Patrick; Jenkins, Cathy A; Kampe, Christy; Khan, Yosef; Kumar, Vijaya A; Lindenfeld, JoAnn; Liu, Dandan; Miller, Karen; Peacock, W Frank; Rizk, Samaa; Robichaux, Chad; Rothman, Russell L; Schrock, Jon; Singer, Adam; Sterling, Sarah A; Storrow, Alan B; Walsh, Cheryl; Wilburn, John; Collins, Sean P

    2017-02-01

    GUIDED-HF (Get With the Guidelines in Emergency Department Patients With Heart Failure) is a multicenter randomized trial of a patient-centered transitional care intervention in patients with acute heart failure (AHF) who are discharged either directly from the emergency department (ED) or after a brief period of ED-based observation. To optimize care and reduce ED and hospital revisits, there has been significant emphasis on improving transitions at the time of hospital discharge for patients with HF. Such efforts have been almost exclusively directed at hospitalized patients; individuals with AHF who are discharged from the ED or ED-based observation are not included in these transitional care initiatives. Patients with AHF discharged directly from the ED or after a brief period of ED-based observation are randomly assigned to our transition GUIDED-HF strategy or standard ED discharge. Patients in the GUIDED arm receive a tailored discharge plan via the study team, based on their identified barriers to outpatient management and associated guideline-based interventions. This plan includes conducting a home visit soon after ED discharge combined with close outpatient follow-up and subsequent coaching calls to improve postdischarge care and avoid subsequent ED revisits and inpatient admissions. Up to 700 patients at 11 sites will be enrolled over 3 years of the study. GUIDED-HF will test a novel approach to AHF management strategy that includes tailored transitional care for patients discharged from the ED or ED-based observation. If successful, this program may significantly alter the current paradigm of AHF patient care.

  4. Criteria for decompensation in binocular vision.

    PubMed

    Jenkins, T C; Pickwell, L D; Yekta, A A

    1989-04-01

    Two groups of patients, one under 40 years of age and the other 40 years and over, were divided into subgroups according to whether they had symptoms associated with near vision. A method developed in 'signal detection theory' was used to determine whether a value could be found for heterophoria, or associated heterophoria, which would predict which patients had symptoms due to decompensated heterophoria in normal routine investigation. Receiver operator characteristic curves (ROC curves) were constructed to look for these cut-off values between patients with, and without, symptoms. No value for dissociated heterophoria was found that would discriminate between the symptomatic and asymptomatic patients. It is concluded that heterophoria measurement is not useful as a routine procedure. In the case of associated heterophoria, for the under 40 years age group, patients with a value of 1 prism dioptre or more are more likely to have symptoms than not, and one-third of patients with close work problems have a value of 2 prism dioptres or more. It was rare to find any asymptomatic patient with a value as high as this. In the 40 years and over age group those with an associated heterophoria of 2 prism dioptres or more are more likely to have symptoms than not. One-third of patients in the latter age group, with symptoms, have a value of 3 prism dioptres or more whilst it is rare to find an asymptomatic patient with a value as large as this.

  5. Immunogenicity of hepatitis A vaccination in decompensated cirrhotic patients.

    PubMed

    Arguedas, M R; Johnson, A; Eloubeidi, M A; Fallon, M B

    2001-07-01

    Hepatitis A virus (HAV) vaccination is recommended in chronic liver disease because of an increased morbidity and mortality associated with HAV superinfection. However, data regarding the efficacy of HAV vaccination in patients with advanced chronic liver disease is limited. We assessed the efficacy of a standard HAV vaccination schedule in decompensated chronic liver disease in comparison with compensated disease and defined clinical predictors associated with seroconversion. Eighty-four anti-HAV antibody-negative patients, 49 with compensated liver disease, and 35 with decompensated disease were enrolled. Seroconversion was measured by qualitative and quantitative anti-HAV antibody measurements 1 month after each vaccine dose, and univariate/multivariate analysis was performed to define clinical predictors associated with seroconversion. One month after the primary dose, 71.4% of patients with compensated liver disease had detectable anti-HAV antibody compared with 37.1% with decompensated liver disease (P <.05). One month after the booster dose, 98% of compensated patients seroconverted compared with 65.7% with decompensated disease (P <.05). The median serum antibody concentration in compensated liver disease was 76.4 mIU/mL at month 1 and 327.91 mIU/mL at month 7 compared with 20.0 mIU/mL and 102.57 mIU/mL, respectively, in decompensated disease. On multivariate analysis, Child-Pugh class was the only factor predicting response to vaccination. Seroconversion after HAV vaccination was significantly less common in decompensated liver disease and the presence of advanced disease (Child-Pugh class B/C) predicted a lower response rate. These findings indicate that the response to HAV vaccination in chronic liver disease is optimal when targeted to patients before the development of hepatic decompensation.

  6. Antiviral therapy for hepatitis B virus-related decompensated cirrhosis.

    PubMed

    Wang, Ji Yao

    2012-11-01

    Antiviral therapy is important in patients with hepatitis B virus (HBV)-related decompensated cirrhosis. This therapy is beneficial in most patients for the stabilization or improvement of liver disease; however, advanced cirrhosis with a high Child-Pugh or model for end-stage liver disease (MELD) score may have progressed and does not benefit from antiviral therapy. It is important to identify patients with severe decompensated cirrhosis who will not improve under antiviral therapy and who require liver transplantation as early as possible. Entecavir (ETV) or tenofovir disoproxil fumarate (TDF) is the first-line therapy for nucleos(t)ide analogue (NA)-naive patients with decompensated cirrhosis due to their potent and prompt HBV suppressive effect and low rate of drug-resistant mutations. Patients on antiviral therapy should be monitored for virological and clinical response, compliance, drug resistance and adverse effects as well as surveillance for hepatocellular carcinoma (HCC). Additional studies of TDF and ETV are necessary to determine the optimal agent(s) for treating naive patients and those with drug-resistant decompensated cirrhosis. In order to evaluate the effectiveness of NA for the treatment of decompensated cirrhotic patients in the real world, high quality observational studies such as registration studies of antiviral therapy for HBV-related cirrhosis and a long-term follow-up in China, where a large number of such patients are found, are recommended.

  7. The Decompensated Monofixation Syndrome (An American Ophthalmological Society Thesis)

    PubMed Central

    Siatkowski, R. Michael

    2011-01-01

    Purpose To describe the clinical features and response to treatment of patients with decompensated monofixation syndrome (MFS) and to propose a hypothesis for a decompensation mechanism in such patients. Methods Fourteen adults with MFS who had been symptomatically stable for a mean duration of 25 years developed diplopia in the absence of neurologic or orbital disease. After retrospective chart review, they underwent detailed orthoptic testing. Results from this cross-sectional analysis were compared with similar data from 16 control subjects with stable MFS. Results Compared to stable MFS patients, decompensated subjects had significantly poorer horizontal fusional amplitudes but greater torsional fusional amplitudes; they were also more likely to have a small vertical strabismus and to have received initial treatment later. Stable subjects, however, also had subnormal horizontal as well as torsional fusional amplitudes. There was no difference between groups with respect to refractive error, amblyopia, type or prior treatment of strabismus, stereoacuity, or angle of deviation. After treatment, all patients regained monofixational alignment, but up to one-third had continued diplopia. Symptoms recurred in two patients whose treatment was initially successful. Conclusions Patients with MFS lose fusional amplitudes over time. In some cases this results in development of sensory torsion with secondary decompensation and diplopia. The rate of decompensation averages 7% per year from ages 20 to 70. Treatment for decompensation offers excellent motor results, but sensory symptoms may persist and recurrent symptoms may develop. Monitoring and maintenance of fusional vergence amplitudes should be part of the routine care for patients with MFS. PMID:22253490

  8. Demographics, Clinical Characteristics, Management, and Outcomes of Acute Heart Failure Patients: Observations from the Oman Acute Heart Failure Registry

    PubMed Central

    Panduranga, Prashanth; Sulaiman, Kadhim; Al-Zakwani, Ibrahim; Alazzawi, Aouf AbdlRahman; Abraham, Abraham; Singh, Prit Pal; Narayan, Narayan Anantha; Rajarao, Mamatha Punjee; Khdir, Mohammed Ahmed; Abdlraheem, Mohamad; Siddiqui, Aftab Ahmed; Soliman, Hisham; Elkadi, Osama Abdellatif; Bichu, Ruchir Kumar; Al Lawati, Kumayl Hasan

    2016-01-01

    Objectives We sought to describe the demographics, clinical characteristics, management and outcomes of patients in Oman with acute heart failure (AHF) as part of the Gulf aCute heArt failuRe rEgistry (CARE) project. Methods Data were analyzed from 988 consecutive patients admitted with AHF to 12 hospitals in Oman between 14 February and 14 November 2012. Results The mean age of our patients was 63±12 years. Over half (57%) were male and 95% were Omani citizens. Fifty-seven percent of patients presented with acute decompensated chronic heart failure (ADCHF) while 43% had new-onset AHF. The primary comorbid conditions were hypertension (72%), coronary artery disease (55%), and diabetes mellitus (53%). Ischemic heart disease (IHD), hypertensive heart disease, and idiopathic cardiomyopathy were the most common etiologies of AHF in Oman. The median left ventricular ejection fraction of the cohort was 36% (27–45%) with 56% of the patients having heart failure with reduced ejection fraction (< 40%). Atrial fibrillation was seen in 15% of patients. Acute coronary syndrome (ACS) and non-compliance with medications were the most common precipitating factors. At discharge, angiotensin converting enzyme inhibitors and beta-blockers were prescribed adequately, but aldosterone antagonists were under prescribed. Within 12-months follow-up, one in two patients were rehospitalized for AHF. In-hospital mortality was 7.1%, which doubled to 15.7% at three months and reached 26.4% at one-year post discharge. Conclusions Oman CARE was the first prospective multicenter registry of AHF in Oman and showed that heart failure (HF) patients present at a younger age with recurrent ADCHF and HF with reduced ejection fraction. IHD was the most common etiology of HF with a low prevalence of AHF, but a high prevalence of acute coronary syndrome and non-compliance with medications precipitating HF. A quarter of patients died at one-year follow-up even though at discharge medical therapy was

  9. Short-term effect of levosimendan on free light chain kappa and lambda levels in patients with decompensated chronic heart failure.

    PubMed

    Kurt, Ibrahim Halil; Yavuzer, Kemal; Batur, Mustafa Kemal

    2010-09-01

    To investigate the effects of levosimendan, a positive inotropic agent, on the new heart failure markers immunoglobulin free light chains kappa and lambda (FLC-kappa and FLC-lambda) in decompensated chronic heart failure (HF), 59 patients with New York Heart Association (NYHA) class III-IV HF were enrolled. Patients were randomized into levosimendan (n = 31) and standard HF treatment (n = 29) groups. Serum FLC-kappa and FLC-lambda, brain natriuretic peptide (BNP), and ejection fraction (EF) were measured before treatment and on the 5th day of treatment initiation. Forty-two percent of subjects were females (n = 25) and overall mean age was 64.1 +/- 10.7 years. FLC-kappa (P < 0.05) and FLC-lambda (P < 0.05) were significantly decreased in the levosimendan group compared to baseline, but no difference in either marker in the standard treatment group was observed. Pre- and post-treatment FLC-kappa/FLC-lambda ratios in both groups were similar, whereas FLC-kappa and FLC-lambda levels and the FLC-kappa/FLC-lambda ratio showed no significant correlation with NYHA class, brain natriuretic peptide (BNP) and ejection fraction (EF) levels; and BNP and EF changes after the treatment. Symptomatic improvement in the levosimendan group according to the NYHA class was significantly better than in the standard treatment group (P = 0.044). While 55.2% of patients in the levosimendan group showed a 1-degree shift to lower NYHA classes, 10.3% showed a 2-degree decrease. In conclusion, levosimendan caused short-term hemodynamic and symptomatic improvements, with a more pronounced decrease in FLC levels in patients with advanced decompensated HF.

  10. Response to the NCEPOD report: development of a care bundle for patients admitted with decompensated cirrhosis-the first 24 h.

    PubMed

    McPherson, Stuart; Dyson, Jessica; Austin, Andrew; Hudson, Mark

    2016-01-01

    Recently, there has been a significant increase in the prevalence of chronic liver disease in the UK, and as a result, hospital admissions and deaths due to liver disease have also increased. The 2013 National Confidential Enquiry into Patient Outcome and Death (NCEPOD) of patients with alcohol-related liver disease (ARLD) found that less than half the number of patients who died from ARLD received 'good care', and avoidable deaths were identified. In order to improve the care of patients admitted with ARLD, the NCEPOD report recommended that a 'toolkit' for the acute management of patients admitted with decompensated ARLD be developed and made widely available. As a result, we have developed a 'care bundle' for patients admitted with decompensated cirrhosis (of all aetiologies) to ensure that effective evidence-based treatments are delivered within the first 24 h. This care bundle provides a checklist to ensure that all appropriate investigations are undertaken when a patient with decompensated cirrhosis presents and provides clinicians with clear guidance on the initial management of alcohol withdrawal, infection, acute kidney injury, gastrointestinal bleeding and encephalopathy. The first 24 h are particularly important, as early intervention can reduce mortality and shorten hospital stay, and specialist gastroenterology/liver advice is not always available during this period. This review will discuss the care bundle and the evidence base behind the treatment recommendations made.

  11. Lamivudine treatment for decompensated cirrhosis resulting from chronic hepatitis B.

    PubMed

    Villeneuve, J P; Condreay, L D; Willems, B; Pomier-Layrargues, G; Fenyves, D; Bilodeau, M; Leduc, R; Peltekian, K; Wong, F; Margulies, M; Heathcote, E J

    2000-01-01

    The prognosis of decompensated cirrhosis resulting from chronic hepatitis B is poor, and the benefits of treatment with interferon are outweighed by serious side effects and by the risk of fatal exacerbation of disease activity. Lamivudine rapidly reduces hepatitis B virus (HBV)-DNA in serum to undetectable levels. We have treated 35 patients with chronic hepatitis B and decompensated cirrhosis with lamivudine 100 mg or 150 mg orally once daily. Pretreatment, all were positive for HBV-DNA in serum. Ten had Child-Pugh class B and 25 had Child-Pugh class C liver disease. Seven patients underwent liver transplantation within 6 months of treatment initiation, 5 patients died within 6 months, and 23 patients were treated for at least 6 months (mean = 19 months). In a majority of these 23 cases, there was a slow but marked improvement in liver function, which was most apparent after 9 months of treatment, with a decrease in serum bilirubin from 67 +/- 13 to 30 +/- 4 micromol/L (P <.05, baseline vs. 9 months), an increase in serum albumin from 27 +/- 1 to 34 +/- 1g/L (P <.05), and a decrease in Child-Pugh score from 10.3 +/- 0.4 to 7.5 +/- 0.5 (P <.05). Three patients developed resistance to lamivudine because of a mutation in the YMDD motif, but liver function did not deteriorate. We conclude that inhibition of viral replication with lamivudine results in a significant improvement of liver function in patients with decompensated HBV cirrhosis, but the long-term benefits remain uncertain.

  12. Prognostic and diagnostic value of plasma soluble ST2 concentrations in Acute Respiratory Distress Syndrome

    PubMed Central

    Bajwa, Ednan K.; Volk, Jessica A.; Christiani, David C.; Harris, R. Scott; Matthay, Michael A.; Thompson, B. Taylor; Januzzi, James L.

    2013-01-01

    Objective Soluble ST2 (sST2) is a biomarker of myocardial strain and inflammation. The characteristics of acute respiratory distress syndrome (ARDS) include inflammation and cardiovascular dysfunction. We sought to determine whether plasma sST2 concentration is associated with outcome and response to conservative fluid management, and whether sST2 concentration discriminates ARDS from decompensated heart failure (HF). Design, Setting, and Patients We assayed plasma sST2 concentrations in 826 patients in the Fluid and Catheter Treatment Trial (FACTT), a multi-center randomized controlled trial of conservative fluid management in ARDS, as well as a cohort of patients with decompensated HF. We tested whether sST2 was associated with outcome, response to therapy, and diagnostic utility for ARDS vs. HF. Measurements and Main Results Non-survivors had higher day 0 (P<.0001) and day 3 (P<.0001) sST2 concentrations. After adjustment for severity of illness, higher sST2 concentration was associated with mortality, with odds ratio (ORadj) 1.47 (95% confidence interval [CI] 0.99 – 2.20, P=.06) at day 0, 2.94 (95% CI 2.00 – 4.33, P<.0001) at day 3, and 3.63 (95% CI 2.38 – 5.53, P<.0001) if sST2 increased between days. Cumulative fluid balance was more positive among patients with higher day 0 (median 5212 mL, interquartile range [IQR] 200 – 12284 vs. 2020 mL, −2034 – 7091; P<0.0001), and day 3 sST2 (median 7678 mL, IQR 2217 – 14278 vs. 1492 mL, −2384 – 6239; P<0.0001). sST2 showed excellent discriminative ability between the FACTT and HF populations (Area under ROC curve=0.98, P<0.0001). Conclusions Higher sST2 concentrations are associated with worse outcome in ARDS and may have value for discriminating ARDS from heart failure. PMID:23939353

  13. Acute Effects of Continuous Positive Air way Pressure on Pulse Pressure in Chronic Heart Failure

    PubMed Central

    Quintão, Mônica; Chermont, Sérgio; Marchese, Luana; Brandão, Lúcia; Bernardez, Sabrina Pereira; Mesquita, Evandro Tinoco; Rocha, Nazareth de Novaes; Nóbrega, Antônio Claudio L.

    2014-01-01

    Background Patients with heart failure (HF) have left ventricular dysfunction and reduced mean arterial pressure (MAP). Increased adrenergic drive causes vasoconstriction and vessel resistance maintaining MAP, while increasing peripheral vascular resistance and conduit vessel stiffness. Increased pulse pressure (PP) reflects a complex interaction of the heart with the arterial and venous systems. Increased PP is an important risk marker in patients with chronic HF (CHF). Non-invasive ventilation (NIV) has been used for acute decompensated HF, to improve congestion and ventilation through both respiratory and hemodynamic effects. However, none of these studies have reported the effect of NIV on PP. Objective The objective of this study was to determine the acute effects of NIV with CPAP on PP in outpatients with CHF. Methods Following a double-blind, randomized, cross-over, and placebo-controlled protocol, twenty three patients with CHF (17 males; 60 ± 11 years; BMI 29 ± 5 kg/cm2, NYHA class II, III) underwent CPAP via nasal mask for 30 min in a recumbent position. Mask pressure was 6 cmH2O, whereas placebo was fixed at 0-1 cmH2O. PP and other non invasive hemodynamics variables were assessed before, during and after placebo and CPAP mode. Results CPAP decreased resting heart rate (Pre: 72 ± 9; vs. Post 5 min: 67 ± 10 bpm; p < 0.01) and MAP (CPAP: 87 ± 11; vs. control 96 ± 11 mmHg; p < 0.05 post 5 min). CPAP decreased PP (CPAP: 47 ± 20 pre to 38 ± 19 mmHg post; vs. control: 42 ± 12 mmHg, pre to 41 ± 18 post p < 0.05 post 5 min). Conclusion NIV with CPAP decreased pulse pressure in patients with stable CHF. Future clinical trials should investigate whether this effect is associated with improved clinical outcome. PMID:24676373

  14. Ratio of Systolic Blood Pressure to Right Atrial Pressure, a Novel Marker to Predict Morbidity and Mortality in Acute Systolic Heart Failure.

    PubMed

    Omar, Hesham R; Charnigo, Richard; Guglin, Maya

    2017-04-01

    Congestion is the main contributor to heart failure (HF) morbidity and mortality. We assessed the combined role of congestion and decreased forward flow in predicting morbidity and mortality in acute systolic HF. The Evaluation Study of Congestive Heart Failure and Pulmonary Artery Catheterization Effectiveness trial data set was used to determine if the ratio of simultaneously measured systolic blood pressure (SBP)/right atrial pressure (RAP) on admission predicted HF rehospitalization and 6-month mortality. One hundred ninety-five patients (mean age 56.5 years, 75% men) who received pulmonary artery catheterization were studied. The RAP, SBP, and SBP/RAP had an area under the curve (AUC) of 0.593 (p = 0.0205), 0.585 (p = 0.0359), and 0.621 (p = 0.0026), respectively, in predicting HF rehospitalization. The SBP/RAP was a superior marker of HF rehospitalization compared with RAP alone (difference in AUC 0.0289, p = 0.0385). The optimal criterion of SBP/RAP <11 provided the highest combined sensitivity (77.1%) and specificity (50.9%) in predicting HF rehospitalization. The SBP/RAP had an AUC 0.622, p = 0.0108, and a cut-off value of SBP/RAP <8 had a sensitivity of 61.9% and specificity 64.1% in predicting mortality. Multivariate analysis showed that an SBP/RAP <11 independently predicted rehospitalization for HF (estimated odds ratio 3.318, 95% confidence interval 1.692 to 6.506, p = 0.0005) and an SBP/RAP <8 independently predicted mortality (estimated hazard ratio 2.025, 95% confidence interval 1.069 to 3.833, p = 0.030). In conclusion, SBP/RAP ratio is a marker that identifies a spectrum of complications after hospitalization of patients with decompensated systolic HF, starting with increased incidence of HF rehospitalization at SBP/RAP <11 to increased mortality with SBP/RAP <8.

  15. Pulsed inductive HF laser

    NASA Astrophysics Data System (ADS)

    Razhev, A. M.; Churkin, D. S.; Kargapol'tsev, E. S.; Demchuk, S. V.

    2016-03-01

    We report the results of experimentally investigated dependences of temporal, spectral and spatial characteristics of an inductive HF-laser generation on the pump conditions. Gas mixtures H2 - F2(NF3 or SF66) and He(Ne) - H2 - F2(NF3 or SF6) were used as active media. The FWHM pulse duration reached 0.42 μs. This value corresponded to a pulsed power of 45 kW. For the first time, the emission spectrum of an inductive HF laser was investigated, which consisted of seven groups of bands with centres around the wavelengths of 2732, 2736, 2739, 2835, 2837, 2893 and 2913 nm. The cross section profile of the laser beam was a ring with a diameter of about 20 mm and width of about 5 mm. Parameters of laser operation in the repetitively pulsed regime were sufficiently stable. The amplitude instability of light pulses was no greater than 5% - 6%.

  16. Modern HF Communications.

    DTIC Science & Technology

    1983-05-01

    AD-A131 163 MODERN HF COUNICATIONS(U) ADVISORY GROUP FOR AEROSPACE RESEARCH AND DEVELOPMENT NEUILLY-SUR-SEINE (FRANCE) d AARONS ET AL. MAY 83 AGARD...NORTH ATLANTIC TREATY ORGANIZATION ADVISORY GROUP FOR AEROSPACE RESEARCH AND DEVELOPMENT (ORGANISATION DU TRAITE DE L’ATLANTIQUE NORD) AGARD Lecture...other NATO bodies and to member nation-, in connection with research aind development problems in the aerospace field: Plros iding assistance to

  17. Glycated Hemoglobin Levels in Patients with Decompensated Cirrhosis

    PubMed Central

    Satapathy, Sanjaya K.

    2016-01-01

    Introduction. Aim of this study is to determine if HbA1c levels are a reliable predictor of glycemic control in patients with decompensated cirrhosis. Methods. 200 unique patients referred for liver transplantation at University of Tennessee/Methodist University Transplant Institute with a HbA1c result were included. Three glucose levels prior to the “measured” A1c (MA1c) were input into an HbA1c calculator from the American Diabetes Association website to determine the “calculated” A1c (CA1c). The differences between MA1c and CA1c levels were computed. Patients were divided into three groups: group A, difference of <0.5; group B, 0.51–1.5; and group C, >1.5. Results. 97 (49%) patients had hemoglobin A1c of less than 5%. Discordance between calculated and measured HbA1c of >0.5% was seen in 47% (n = 94). Higher level of discordance of greater than >1.5 was in 12% of patients (n = 24). Hemoglobin was an independent predictor for higher discordance (odds ratio 0.77 95%, CI 0.60–0.99, and p value 0.04). HbA1c was an independent predictor of occurrence of HCC (OR 2.69 955, CI 1.38–5.43, and p value 0.008). Conclusion. HbA1c is not a reliable predictor of glycemic control in patients with decompensated cirrhosis, especially in those with severe anemia. PMID:27882051

  18. Hepatic decompensation with sofosbuvir plus simeprevir in a patient with Child-Pugh B compensated cirrhosis.

    PubMed

    Soriano, Vincent; Barreiro, Pablo; de Mendoza, Carmen; Peña, José M

    2016-01-01

    A 75-year-old male with compensated Child-Pugh B cirrhosis initiated sofosbuvir plus simeprevir, and developed hepatic decompensation and died a few days thereafter. High exposure to simeprevir leading to hepatotoxicity most likely explained this fatal outcome. This observation, along with similar cases recently reported in the literature, should raise awareness of the potential for decompensation in patients with advanced cirrhosis treated with simeprevir.

  19. Pulsed inductive HF laser

    SciTech Connect

    Razhev, A M; Kargapol'tsev, E S; Churkin, D S; Demchuk, S V

    2016-03-31

    We report the results of experimentally investigated dependences of temporal, spectral and spatial characteristics of an inductive HF-laser generation on the pump conditions. Gas mixtures H{sub 2} – F{sub 2}(NF{sub 3} or SF6{sub 6}) and He(Ne) – H{sub 2} – F{sub 2}(NF{sub 3} or SF{sub 6}) were used as active media. The FWHM pulse duration reached 0.42 μs. This value corresponded to a pulsed power of 45 kW. For the first time, the emission spectrum of an inductive HF laser was investigated, which consisted of seven groups of bands with centres around the wavelengths of 2732, 2736, 2739, 2835, 2837, 2893 and 2913 nm. The cross section profile of the laser beam was a ring with a diameter of about 20 mm and width of about 5 mm. Parameters of laser operation in the repetitively pulsed regime were sufficiently stable. The amplitude instability of light pulses was no greater than 5% – 6%. (lasers)

  20. Update: Acute Heart Failure (VII): Nonpharmacological Management of Acute Heart Failure.

    PubMed

    Plácido, Rui; Mebazaa, Alexandre

    2015-09-01

    Acute heart failure is a major and growing public health problem worldwide with high morbidity, mortality, and cost. Despite recent advances in pharmacological management, the prognosis of patients with acute decompensated heart failure remains poor. Consequently, nonpharmacological approaches are being developed and increasingly used. Such techniques may include several modalities of ventilation, ultrafiltration, mechanical circulatory support, myocardial revascularization, and surgical treatment, among others. This document reviews the nonpharmacological approach in acute heart failure, indications, and prognostic implications.

  1. Nonalcoholic fatty liver disease and increased risk of 1-year all-cause and cardiac hospital readmissions in elderly patients admitted for acute heart failure

    PubMed Central

    Valbusa, Filippo; Bonapace, Stefano; Agnoletti, Davide; Scala, Luca; Grillo, Cristina; Arduini, Pietro; Turcato, Emanuela; Mantovani, Alessandro; Zoppini, Giacomo; Arcaro, Guido; Byrne, Christopher; Targher, Giovanni

    2017-01-01

    Nonalcoholic fatty liver disease (NAFLD) is an emerging risk factor for heart failure (HF). Although some progress has been made in improving survival among patients admitted for HF, the rates of hospital readmissions and the related costs continue to rise dramatically. We sought to examine whether NAFLD and its severity (diagnosed at hospital admission) was independently associated with a higher risk of 1-year all-cause and cardiac re-hospitalization in patients admitted for acute HF. We studied 212 elderly patients who were consecutively admitted with acute HF to the Hospital of Negrar (Verona) over a 1-year period. Diagnosis of NAFLD was based on ultrasonography, whereas the severity of advanced NAFLD fibrosis was based on the fibrosis (FIB)-4 score and other non-invasive fibrosis scores. Patients with acute myocardial infarction, severe valvular heart diseases, end-stage renal disease, cancer, known liver diseases or decompensated cirrhosis were excluded. Cox regression was used to estimate hazard ratios (HR) for the associations between NAFLD and the outcome(s) of interest. The cumulative rate of 1-year all-cause re-hospitalizations was 46.7% (n = 99, mainly due to cardiac causes). Patients with NAFLD (n = 109; 51.4%) had remarkably higher 1-year all-cause and cardiac re-hospitalization rates compared with their counterparts without NAFLD. Both event rates were particularly increased in those with advanced NAFLD fibrosis. NAFLD was associated with a 5-fold increased risk of 1-year all-cause re-hospitalization (adjusted-hazard ratio 5.05, 95% confidence intervals 2.78–9.10, p<0.0001) after adjustment for established risk factors and potential confounders. Similar results were found for 1-year cardiac re-hospitalization (adjusted-hazard ratio 8.05, 95% confidence intervals 3.77–15.8, p<0.0001). In conclusion, NAFLD and its severity were strongly and independently associated with an increased risk of 1-year all-cause and cardiac re-hospitalization in elderly

  2. HF mitigation via the Texaco-UOP HF additive technology

    SciTech Connect

    Sheckler, J.C.; Hammershaimb, H.U. ); Ross, L.J. ); Comey, K.R. III . Research and Development)

    1994-01-01

    Alkylation is one of the key processes used by refiners to produce high-octane gasoline. In the alkylation process, light olefins and isobutane are converted to alkylate, a high-octane, low-vapor-pressure, paraffinic gasoline-blending component. Because of its clean burning characteristics and ability to contribute to lower emissions, alkylate is a highly valued component in premium and reformulated gasolines. Alkylation process technology using hydrogen fluoride (HF) as a catalyst has been widely used for many years. Since the mid-1980s, a primary concern has been the tendency of HF to form an aerosol when HF is released to the atmosphere. Much effort has gone into the development of measures to ensure the safe handling of HF in the refinery environment. Texaco and UOP have under development an HF additive technology. The key to this technology is the discovery of a class of additives that form a complex with HF to significantly reduce the aerosol-forming tendency of the catalyst system and still maintain acceptable catalytic performance and product quality. The purpose of this paper is to provide an update on the development status of the Texaco-UOP HF additive technology. Aerosol reduction has been demonstrated in small-scale laboratory release tests as well as in larger scale wind tunnel release tests. The catalytic performance of the HF additive has been demonstrated in laboratory alkylation facilities and in a short-term experimental trial in a full-scale refinery unit. On the basis of the positive results obtained in the test program, a project is under way to implement the HF additive technology on a continuous basis in an existing Texaco alkylation unit by the third quarter of 1994.

  3. [Pulmonary embolism and sibilant types of chronic obstructive pulmonary disease decompensations].

    PubMed

    Mispelaere, D; Glerant, J C; Audebert, M; Remond, A; Sevestre-Pietri, M A; Jounieaux, V

    2002-09-01

    Pulmonary Embolism (PE) poses an important diagnostic problem in patients with chronic obstructive pulmonary disease (COPD). Indeed PE may aggravate the already precarious respiratory state of these fragile patients. Moreover, these two conditions share common symptoms: dyspnoea, wheezing, pleural pain, haemoptysis, palpitations and signs of right cardiac insufficiency. In two studies, one retrospective and the other prospective, we investigated the incidence of PE in patients with non-infective exacerbations of their COPD. The retrospective study was carried out over two years and involved 50 COPD patients with non-infective respiratory exacerbations. In this population, 10 patients out of 50 (20%) had a documented PE. No predictive factor was identified. The prospective study was conducted over one year and COPD patients admitted to hospital with exacerbations were included in the study if they had a positive D-dimer blood test and no evidence of acute respiratory infection. 31 patients were studied with Doppler ultra-sound examination of the legs and a lung perfusion scan. The presence or absence of PE was determined and the two groups were compared. 9 patients out of 31 (29%) had a documented PE. Six of these nine patients had a deep venous thrombosis (DVT). Two predictive factors of PE were identified: existence of a DVT and a significant fall in PaO(2) from baseline state (DeltaPaO(2) > 22 mmHg). We conclude that PE is a frequent (20 to 30%) of non-infective respiratory decompensation in COPD patients. Faced with an unexplained respiratory exacerbation in these patients, a lung perfusion scan should be routinely undertaken to rule out a PE when the D-dimers are positive.

  4. Human umbilical cord mesenchymal stem cells improve liver function and ascites in decompensated liver cirrhosis patients.

    PubMed

    Zhang, Zheng; Lin, Hu; Shi, Ming; Xu, Ruonan; Fu, Junliang; Lv, Jiyun; Chen, Liming; Lv, Sa; Li, Yuanyuan; Yu, Shuangjie; Geng, Hua; Jin, Lei; Lau, George K K; Wang, Fu-Sheng

    2012-03-01

    Decompensated liver cirrhosis (LC), a life-threatening complication of chronic liver disease, is one of the major indications for liver transplantation. Recently, mesenchymal stem cell (MSC) transfusion has been shown to lead to the regression of liver fibrosis in mice and humans. This study examined the safety and efficacy of umbilical cord-derived MSC (UC-MSC) in patients with decompensated LC. A total of 45 chronic hepatitis B patients with decompensated LC, including 30 patients receiving UC-MSC transfusion, and 15 patients receiving saline as the control, were recruited; clinical parameters were detected during a 1-year follow-up period. No significant side-effects and complications were observed in either group. There was a significant reduction in the volume of ascites in patients treated with UC-MSC transfusion compared with controls (P < 0.05). UC-MSC therapy also significantly improved liver function, as indicated by the increase of serum albumin levels, decrease in total serum bilirubin levels, and decrease in the sodium model for end-stage liver disease scores. UC-MSC transfusion is clinically safe and could improve liver function and reduce ascites in patients with decompensated LC. UC-MSC transfusion, therefore, might present a novel therapeutic approach for patients with decompensated LC.

  5. Home telemonitoring study for Japanese patients with heart failure (HOMES-HF): protocol for a multicentre randomised controlled trial

    PubMed Central

    Kotooka, Norihiko; Asaka, Machiko; Sato, Yasunori; Kinugasa, Yoshiharu; Nochioka, Kotaro; Mizuno, Atsushi; Nagatomo, Daisuke; Mine, Daigo; Yamada, Yoko; Eguchi, Kazuo; Hanaoka, Hideki; Inomata, Takayuki; Fukumoto, Yoshihiro; Yamamoto, Kazuhiro; Tsutsui, Hiroyuki; Masuyama, Tohru; Kitakaze, Masafumi; Inoue, Teruo; Shimokawa, Hiroaki; Momomura, Shin-ichi; Seino, Yoshihiko; Node, Koichi

    2013-01-01

    Introduction Despite the encouraging results from several randomised controlled trials (RCTs) and meta-analyses, the ability of home telemonitoring for heart failure (HF) to improve patient outcomes remains controversial as a consequence of the two recent large-scale RCTs. However, it has been suggested that there is a subgroup of patients with HF who may benefit from telemonitoring. The aim of the present study was to investigate whether an HF management programme using telemonitoring could improve outcomes in patients with HF under the Japanese healthcare system. Methods and analysis The Home Telemonitoring Study for Japanese Patients with Heart Failure (HOMES-HF) study is a prospective, multicentre RCT to investigate the effectiveness of home telemonitoring on the primary composite endpoint of all-cause death and rehospitalisation due to worsening HF in recently admitted HF patients (aged 20 and older, New York Heart Association classes II–III). The telemonitoring system is an automated physiological monitoring system including body weight, blood pressure and pulse rate by full-time nurses 7 days a week. Additionally, the system was designed to make it a high priority to support patient's self-care instead of an early detection of HF decompensation. A total sample size of 420 patients is planned according to the Schoenfeld and Richter method. Eligible patients are randomly assigned via a website to either the telemonitoring group or the usual care group by using a minimisation method with biased-coin assignment balancing on age, left ventricular ejection fraction and a history of ischaemic heart disease. Participants will be enrolled until August 2013 and followed until August 2014. Time to events will be estimated using the Kaplan-Meier method, and HRs and 95% CIs will be calculated using the Cox proportional hazards models with stratification factors. Trial Registration: The study is registered at UMIN Clinical Trials Registry (UMIN000006839). PMID

  6. Marburg Hemorrhagic Fever (Marburg HF)

    MedlinePlus

    ... The CDC Cancel Submit Search The CDC Marburg hemorrhagic fever (Marburg HF) Note: Javascript is disabled or is ... was first recognized in 1967, when outbreaks of hemorrhagic fever occurred simultaneously in laboratories in Marburg and Frankfurt, ...

  7. Successful pregnancy outcome in decompensated chronic liver disease with portal vein thrombosis: case report and review of literature.

    PubMed

    Kumar, Mukesh; Kamani, Lubna; Hussain, Riaz; Siddique, Shoaib

    2011-07-01

    Pregnancy is rare in women with decompensated chronic liver disease. In this case report, we describe a case of a young woman who presented with hepatitis B-related decompensated chronic liver disease with portal vein thrombosis having successful full-term uneventful pregnancy.

  8. Specialist intervention is associated with improved patient outcomes in patients with decompensated heart failure: evaluation of the impact of a multidisciplinary inpatient heart failure team

    PubMed Central

    Masters, Jayne; Morton, Geraint; Anton, Isabel; Szymanski, Jane; Greenwood, Elizabeth; Grogono, Joanna; Flett, Andrew S; Cleland, John G F; Cowburn, Peter J

    2017-01-01

    Objective The study aimed to evaluate the impact of a multidisciplinary inpatient heart failure team (HFT) on treatment, hospital readmissions and mortality of patients with decompensated heart failure (HF). Methods A retrospective service evaluation was undertaken in a UK tertiary centre university hospital comparing 196 patients admitted with HF in the 6 months prior to the introduction of the HFT (pre-HFT) with all 211 patients seen by the HFT (post-HFT) during its first operational year. Results There were no significant differences in patient baseline characteristics between the groups. Inpatient mortality (22% pre-HFT vs 6% post-HFT; p<0.0001) and 1-year mortality (43% pre-HFT vs 27% post-HFT; p=0.001) were significantly lower in the post-HFT cohort. Post-HFT patients were significantly more likely to be discharged on loop diuretics (84% vs 98%; p=<0.0001), ACE inhibitors (65% vs 76%; p=0.02), ACE inhibitors and/or angiotensin receptor blockers (83% vs 91%; p=0.02), and mineralocorticoid receptor antagonists (44% vs 68%; p<0.0001) pre-HFT versus post-HFT, respectively. There was no difference in discharge prescription rates of beta-blockers (59% pre-HFT vs 63% post-HFT; p=0.45). The mean length of stay (17±19 days pre-HFT vs 19±18 days post-HFT; p=0.06), 1-year all-cause readmission rates (46% pre-HFT vs 47% post-HFT; p=0.82) and HF readmission rates (28% pre-HFT vs 20% post-HFT; p=0.09) were not different between the groups. Conclusions The introduction of a specialist inpatient HFT was associated with improved patient outcome. Inpatient and 1-year mortality were significantly reduced. Improved use of evidence-based drug therapies, more intensive diuretic use and multidisciplinary care may contribute to these differences in outcome.

  9. Antiviral therapy in compensated and decompensated cirrhotic patients with chronic HCV infection.

    PubMed

    Iacobellis, Angelo; Andriulli, Angelo

    2009-08-01

    Liver cirrhosis secondary to HCV infection is a chronic disorder that carries high morbidity and mortality. Approved antiviral treatment for this condition at present includes peginterferon in combination with ribavirin. Treatment is only recommended for a well-compensated liver cirrhosis, whereas antiviral therapy is commonly not implemented in cirrhotics with signs of liver decompensation, over the concern that the use of peginterferon and ribavirin might expose patients to severe treatment-related side effects. This review focuses on data available to support both efficacy and safety of antiviral therapy in both compensated and decompensated cirrhotic patients.

  10. TLR4/CD14 Variants-Related Serologic and Immunologic Dys-Regulations Predict Severe Sepsis in Febrile De-Compensated Cirrhotic Patients

    PubMed Central

    Fan, Wen-Chien; Liu, Chih-Wei; Ou, Shuo-Ming; Huang, Chia-Chang; Li, Tzu-Hao; Lee, Kuei-Chuan; Huang, Shiang-Fen; Yang, Ying-Ying; Hsieh, Yun-Cheng; Hsieh, Shie-Liang; Hou, Ming-Chih; Lin, Han-Chieh

    2016-01-01

    Genetic variants and dysfunctional monocyte had been reported to be associated with infection susceptibility in advanced cirrhotic patients. This study aims to explore genetic predictive markers and relevant immune dysfunction that contributed to severe sepsis in febrile acute de-compensated cirrhotic patents. Polymorphism analysis of candidate genes was undergone in 108 febrile acute de-compensated cirrhotic patients and 121 healthy volunteers. Various plasma inflammatory/regulatory cytokines, proportion of classical (CD 16-, phagocytic) and non-classical (CD16+, inflammatory) monocytes, lipopolysaccharide (LPS)-stimulated toll-like receptor 4 (TLR4) and intracellular/extracellular cytokines on cultured non-classical monocytes, mCD14/HLA-DR expression and phagocytosis of classical monocytes were measured. For TLR4+896A/G variant allele carriers with severe sepsis, high plasma endotoxin/IL-10 inhibits HLA-DR expression and impaired phagocytosis were noted in their classical monocyte. In the same group, increased non-classical monocyte subset, enhanced LPS-stimulated TLR4 expression and TNFα/nitrite production, and systemic inflammation [high plasma soluble CD14 (sCD14) and total nitric oxide (NOx) levels] were noted. For CD14-159C/T variant allele carriers with severe sepsis, persist endotoxemia inhibited mCD14/HLA-DR expression and impaired phagocytosis of their classical monocyte. In the same group, increased non-classical monocyte subset up-regulated TLR4-NFκB-iNOS and p38MAPK pathway, stimulated TNFα/nitrite production and elicited systemic inflammation. In febrile acute de-compensated cirrhotic patients, TLR4+896A/G and CD14-159C/T polymorphisms-related non-classical and classical monocytes dysfunction resulted in increased severe sepsis risk. Malnutrition, high plasma endotoxin and sCD14 levels, single TLR4+896A/G or CD14-159C/T variant allele carriers and double variant allele carriers are significant predictive factors for the development of severe

  11. [Data from the IN-HF Outcome registry].

    PubMed

    Misuraca, Gianfranco; Di Tano, Giuseppe; Camerini, Alberto; Cloro, Cosima; Gorini, Marco

    2012-05-01

    The IN-HF Outcome registry enrolled 1855 patients admitted for acute heart failure and 3755 outpatients with chronic heart failure seen at 64 cardiology units of the Italian Network-Heart Failure. We assessed gender-related differences in clinical characteristics, management, and short- and long-term mortality and morbidity outcomes. Women were older, more often hypertensive and with a higher prevalence of heart failure with preserved systolic function. Aggressive management was less frequent in women who underwent less often diagnostic and therapeutic procedures. We found no gender-related differences in either acute or long-term mortality nor in hospital readmissions.

  12. Acute oesophageal necrosis (black oesophagus).

    PubMed

    Galtés, Ignasi; Gallego, María Ángeles; Esgueva, Raquel; Martin-Fumadó, Carles

    2016-03-01

    A 54-year-old man was admitted to hospital after being found unconscious in his home. He had a history of alcoholism, multiple drug addictions, and type I diabetes mellitus. At admission, he had hyperglycaemia (550 mg/dL) with glucosuria and ketone bodies in the urine, along with septic shock refractory to bilateral alveolar infiltrates and severe respiratory failure. The patient died 24 hours post admission due to multiple organ failure, with diabetic ketoacidosis decompensated by possible respiratory infection in a patient with polytoxicomania. The autopsy confirmed the presence of acute bilateral bronchopneumonia, chronic pancreatitis, severe hepatic steatosis, and generalized congestive changes. At the oesophagus, acute oesophageal necrosis was evident.

  13. High serum ferritin is associated with worse outcome of patients with decompensated cirrhosis

    PubMed Central

    Oikonomou, Theodora; Goulis, Ioannis; Soulaidopoulos, Stergios; Karasmani, Areti; Doumtsis, Petros; Tsioni, Konstantina; Mandala, Eudokia; Akriviadis, Evangelos; Cholongitas, Evangelos

    2017-01-01

    Background Studies in patients with decompensated cirrhosis showed a correlation between serum ferritin levels and patients’ prognosis. Besides, red blood cell distribution width (RDW) and mean platelet volume (MPV) have been associated with the severity of hepatic function. The aim of this study was to evaluate the prognostic impact of serum ferritin and RDW/MPV in the outcome [survival, death, or liver transplantation (LT)] of patients with stable decompensated cirrhosis. Methods Consecutive adult patients with stable decompensated cirrhosis admitted to our department between September 2010 and February 2016 were included. Serum ferritin, RDW and MPV were recorded in every patient. They were followed up and their outcome (alive, death, or LT) was evaluated. Results 192 consecutive patients with stable decompensated cirrhosis (142 men, age 54.2±12 years); at the end of follow up [12 (range: 1-64) months] 62 patients remained alive and 130 died or underwent LT. In multivariate analysis, serum ferritin (HR 1.001, 95%CI 1.00-1.002, P=0.005) and GFR (HR 0.96, 95%CI 0.92-0.99, P=0.035) were the only independent factors significantly associated with the outcome. Ferritin had low discriminative ability (AUC: 0.61) to the outcome yielding a sensitivity and specificity of 85.3% and 44.2%, respectively, at the best cut-off point (>55 ng/mL), while patients with ferritin >55 ng/mL (n=145) had a worse outcome compared to those with ferritin ≤55 ng/mL (n=47) (log rank P=0.001). RDW and MPV were not associated with the outcome. Conclusion High serum ferritin, but not RDW/MPV, is associated with worse outcome in patients with established decompensated cirrhosis. However, further studies are needed to elucidate better this issue. PMID:28243043

  14. Predictors of survival in hepatitis B virus related decompensated cirrhosis on tenofovir therapy: an Indian perspective.

    PubMed

    Srivastava, Manjita; Rungta, Sumit; Dixit, V K; Shukla, S K; Singh, T B; Jain, A K

    2013-11-01

    Decompensated cirrhosis has low survival rate compared to compensated state. Effective viral suppression due to antiviral therapy (tenofovir) has been shown to slow disease progression and may delay the burden of liver transplantation. We aimed to evaluate the usefulness of various prognostic indicators in predicting the 24-months survival in HBV related decompensated cirrhosis after tenofovir therapy and to evaluate the post-treatment outcome. Ninety-six HBV related decompensated patients on antiviral (tenofovir) therapy were prospectively studied for 24months survival and mortality. Cutoff levels for several prognostic indicators were generated by ROC. Prediction of overall probability of mortality was also calculated. The overall probability of survival observed at 12months was 0.947 whereas at 24months it was found to be 0.833. According to Cox proportional hazards model, the univariate analysis revealed cutoff of >7.4logcopies/ml for HBV DNA, >1.2mg/dl for serum creatinine, >3.7mg/dl for total bilirubin, ⩽0.75 for platelets count, >10 for CTP and >20 for MELD as predictors of poor survival. Multivariate analysis showed MELD score of >20 was the most robust predictor of mortality, with 58 times higher risk (HR: 58.73, p<0.001). Post-treatment response with tenofovir for 24months significantly improved the hepatic functions and reverses decompensation and showed incredible efficacy in improvement of hepatic functional status with reduced viremia in a great majority of decompensated cirrhosis subjects having high MELD and HBV DNA level.

  15. The decompensative gravity anomaly and deep structure of the region of the Rio Grande rift

    SciTech Connect

    Cordell, L. ); Zorin, Y.A. ); Keller, G.R. )

    1991-04-10

    An isostatic correction is commonly made to Bouguer anomaly gravity data to remove the gravity effect of isostatic compensation of topographic loads. In the USSR a decompensative correction has then been made to the isostatic gravity anomaly to remove the gravity effect of isostatic compensation of geologic loads as well. The authors employ here calculations in the wave number domain, leading to an efficient and exact solution. In a 1,200 {times} 1,200 km region centered on the Rio Grande rift the decompensative correction ranges from about {minus}35 to +25 mGal. The decompensative anomaly, highlights an arcuate gravity low and a system of gravity highs inferred to reflect prerift welts of mass concentration which have indirectly influenced the position of the rift and its segmentation and zones of accommodation. Under the assumptions made, if the decompensative anomaly is subtracted from the Bouguer anomaly, then the residual is the gravity anomaly field of deep structure, without gravity effects of shallow sources in the upper crust. Using available seismic data to (weakly) constrain the Moho surface, they invert the residual gravity field for topography of the base of the lithosphere. Lithosphere is found to be 200 km thick in the High Plains; 40-50 km in the eastern Great Basin; 75-100 km in the Colorado Plateau, and as thin as 40 km in the southern Rio Grande rift. In the area studied, the thickness of the lithospere is everwhere greater than that of the crust. The separation of gravity effects made possible by the decompensative correction shows how the rift is fundamentally controlled by thinning of the lithosphere, yet in detail is deflected by long-lived tectonic welts in the shallow, brittle crust.

  16. Pathogenesis and clinical presentation of acute heart failure.

    PubMed

    Ponikowski, Piotr; Jankowska, Ewa A

    2015-04-01

    Acute heart failure constitutes a heterogeneous clinical syndrome, whose pathophysiology is complex and not completely understood. Given the diversity of clinical presentations, several different pathophysiological mechanisms along with factors triggering circulatory decompensation are involved. This article discusses the available evidence on the pathophysiological phenomena attributed or/and associated with episodes of acute heart failure and describes different clinical profiles, which, from a clinical perspective, constitute a key element for therapeutic decision-making.

  17. Radio HF precursors of Earthquakes

    NASA Astrophysics Data System (ADS)

    Ruzhin, Yu.; Nomicos, C.; Vallianatos, F.; Shpakovsky, V.

    The high frequency (HF) earthquake electromagnetic precursors (40-55MHz band) were recorded by the four electromagnetic stations a few days (hours) prior the event associated with earthquakes with magnitude more than 5.0 at Crete Island. These experiments were performed continuously during 1998-2002 and specific peculiarities are found. This is underhorizon epicenter position for main part of events under question. Another unusual result is that such HF preseismic radio noise-like signals are responsible for seaquakes too. We made conclusion about developing of some thunderstorm-like charged clouds activity in atmosphere before the seismic event. As result of our analysis and interpretation of the available data of continuous observations on a network of Crete island we should state here, that in an atmosphere above the sea on the eve of earthquake at heights of 0.1-10 km the spatially distributed spots of sporadic charged clouds are occurred and the conditions for the electrical discharges in an atmosphere are created which can serve a source of HF radio-emission registered by Crete network. The atmosphere theory relations are used to model a corresponding to an anomalous event emissions generation observed on the Crete. The supposed mechanism of preseismic electricity generation is the model of convection carrier started in an atmosphere. It is governed by the horizontal gradient of air temperature. The occurrence of electrical charges in a surface of the sea and transportation them further on heights up to 10 km in our model occurs due to sporadic energy injections that allocated within bottom of the sea as gases and heat. The dimensions of width and height govern the size of atmosphere convection cells in the earthquake preparation area. These dimensions of the sporadic spots are close to 3 km each as it is derived from shadow geometry and spectral fluctuations of HF signal. Based on experience of Crete HF precursors observation the method for satellite mapping

  18. HfS, Hyperfine Structure Fitting Tool

    NASA Astrophysics Data System (ADS)

    Estalella, Robert

    2017-02-01

    Hyperfine Structure Fitting (HfS) is a tool to fit the hyperfine structure of spectral lines with multiple velocity components. The HfS_nh3 procedures included in HfS simultaneously fit the hyperfine structure of the NH3 (J, K) = (1, 1) and (2, 2) transitions, and perform a standard analysis to derive {T}{ex}, NH3 column density, {T}{rot}, and {T}{{k}}. HfS uses a Monte Carlo approach for fitting the line parameters. Special attention is paid to the derivation of the parameter uncertainties. HfS includes procedures that make use of parallel computing for fitting spectra from a data cube.

  19. Orthodontic decompensation in skeletal Class III malocclusion: redefining the amount of movement assessed by Cone-Beam Computed Tomography

    PubMed Central

    Cappellozza, José Antonio Zuega; Guedes, Fabio Pinto; Nary, Hugo; Capelozza, Leopoldino; Cardoso, Mauricio de Almeida

    2015-01-01

    Introduction: Cone-Beam Computed Tomography (CBCT) is essential for tridimensional planning of orthognathic surgery, as it allows visualization and evaluation of bone structures and mineralized tissues. Tomographic slices allow evaluation of tooth inclination and individualization of movement performed during preoperative decompensation. The aim of this paper was to assess maxillary and mandibular incisors inclination pre and post orthodontic decompensation in skeletal Class III malocclusion. Methods: The study was conducted on six individuals with skeletal Class III malocclusion, surgically treated, who had Cone-Beam Computed Tomographic scans obtained before and after orthodontic decompensation. On multiplanar reconstruction view, tomographic slices (axial, coronal and sagittal) were obtained on the long axis of each incisor. The sagittal slice was used for measurement taking, whereas the references used to assess tooth inclination were the long axis of maxillary teeth in relation to the palatal plane and the long axis of mandibular teeth in relation to the mandibular plane. Results: There was significant variation in the inclination of incisors before and after orthodontic decompensation. This change was of greater magnitude in the mandibular arch, evidencing that natural compensation is more effective in this arch, thereby requiring more intensive decompensation. Conclusion: When routinely performed, the protocols of decompensation treatment in surgical individuals often result in intensive movements, which should be reevaluated, since the extent of movement predisposes to reduction in bone attachment levels and root length. PMID:26560818

  20. HIV coinfection shortens the survival of patients with hepatitis C virus-related decompensated cirrhosis.

    PubMed

    Pineda, Juan A; Romero-Gómez, Manuel; Díaz-García, Fernando; Girón-González, José A; Montero, José L; Torre-Cisneros, Julián; Andrade, Raúl J; González-Serrano, Mercedes; Aguilar, José; Aguilar-Guisado, Manuela; Navarro, José M; Salmerón, Javier; Caballero-Granado, Francisco J; García-García, José A

    2005-04-01

    The impact of human immunodeficiency virus (HIV) coinfection on the survival of patients with hepatitis C virus (HCV)-related end-stage liver disease (ESLD) is unknown. Because HIV infection is no longer considered an absolute contraindication for liver transplantation in some countries, it has become a priority to address this topic. The objective of this study was to compare the survival of HIV-infected and HIV-uninfected patients with decompensated cirrhosis due to HCV. In a retrospective cohort study, the survival of 1,037 HCV monoinfected and 180 HCV/HIV-coinfected patients with cirrhosis after the first hepatic decompensation was analyzed. Of the group, 386 (37%) HCV-monoinfected and 100 (56%) HCV/HIV-coinfected subjects died during the follow-up. The median survival time of HIV-infected and HIV-uninfected patients was 16 and 48 months, respectively (P < .001). The relative risk (95% CI) of death for HIV-infected patients was 2.26 (1.51-3.38). Other independent predictors of survival were age older than 63 years (2.25 [1.53-3.31]); Child-Turcotte-Pugh class B versus class A (1.95 [1.41-2.68]) and class C versus class A (2.78 [1.66-4.70]); hepatitis D virus infection (1.56 [1.12-4.77]); model for end-stage liver disease score, (1.05 [1.01-1-11]); more than one simultaneous decompensation (1.23 [1.12-3.33]); and the type of the first hepatic decompensation, with a poorer prognosis associated with encephalopathy compared with portal hypertensive gastrointestinal bleeding (2.03 [1.26-3.10]). In conclusion, HIV coinfection reduces considerably the survival of patients with HCV-related ESLD independently of other markers of poor prognosis. This fact must be taken into account to establish the adequate timing of liver transplantation in HIV-coinfected subjects.

  1. Hepatopulmonary syndrome is associated with the presence of hepatocellular carcinoma in patients with decompensated cirrhosis

    PubMed Central

    Soulaidopoulos, Stergios; Goulis, Ioannis; Giannakoulas, George; Panagiotidis, Theofilos; Doumtsis, Petros; Karasmani, Areti; Oikonomou, Theodora; Tzoumari, Theodora; Karvounis, Haralampos; Cholongitas, Εvangelos

    2017-01-01

    Background Hepatopulmonary syndrome (HPS) is a relatively common complication in patients with decompensated cirrhosis. Our aim was to evaluate the prevalence of HPS, its clinical impact, and the possible association between HPS and characteristics of patients with decompensated cirrhosis. Methods Patients with stable decompensated cirrhosis admitted to our department and assessed for HPS were included. For each patient, several clinical, laboratory and echocardiographic parameters as well as renal function were recorded. The severity of liver disease was evaluated according to the Model for End-stage Liver Disease and Child-Pugh scores, and renal function was assessed using 51chromium complexed with ethylene diamine tetracetic acid. In addition, the short synacthen test was performed in each patient to evaluate the adrenal function. Results Sixty-three patients were enrolled, 26 (41.3%) of whom diagnosed with HPS. In multivariate analysis, the presence of hepatocellular carcinoma [odds ratio (OR) 8.1, 95% confidence interval (CI) 5.3-27.9, P=0.045] and salivary cortisol at T60 (60 min after the intravenous injection of 250 μg corticotropin) (OR 0.88, 95%CI 0.71-0.98, P=0.045) were the factors independently associated with HPS. T60 salivary cortisol had relatively good discriminative ability for the presence of HPS (area under the curve=0.73). The presence of HPS was not associated with the outcome (P=0.22). Conclusion In our cohort of patients with decompensated cirrhosis, the presence of hepatocellular carcinoma and T60 salivary cortisol were the only factors independently associated with HPS. PMID:28243044

  2. The dipolar endofullerene HF@C60

    NASA Astrophysics Data System (ADS)

    Krachmalnicoff, Andrea; Bounds, Richard; Mamone, Salvatore; Alom, Shamim; Concistrè, Maria; Meier, Benno; Kouřil, Karel; Light, Mark E.; Johnson, Mark R.; Rols, Stéphane; Horsewill, Anthony J.; Shugai, Anna; Nagel, Urmas; Rõõm, Toomas; Carravetta, Marina; Levitt, Malcolm H.; Whitby, Richard J.

    2016-10-01

    The cavity inside fullerenes provides a unique environment for the study of isolated atoms and molecules. We report the encapsulation of hydrogen fluoride inside C60 using molecular surgery to give the endohedral fullerene HF@C60. The key synthetic step is the closure of the open fullerene cage with the escape of HF minimized. The encapsulated HF molecule moves freely inside the cage and exhibits quantization of its translational and rotational degrees of freedom, as revealed by inelastic neutron scattering and infrared spectroscopy. The rotational and vibrational constants of the encapsulated HF molecules were found to be redshifted relative to free HF. The NMR spectra display a large 1H-19F J coupling typical of an isolated species. The dipole moment of HF@C60 was estimated from the temperature dependence of the dielectric constant at cryogenic temperatures and showed that the cage shields around 75% of the HF dipole.

  3. The dipolar endofullerene HF@C60.

    PubMed

    Krachmalnicoff, Andrea; Bounds, Richard; Mamone, Salvatore; Alom, Shamim; Concistrè, Maria; Meier, Benno; Kouřil, Karel; Light, Mark E; Johnson, Mark R; Rols, Stéphane; Horsewill, Anthony J; Shugai, Anna; Nagel, Urmas; Rõõm, Toomas; Carravetta, Marina; Levitt, Malcolm H; Whitby, Richard J

    2016-10-01

    The cavity inside fullerenes provides a unique environment for the study of isolated atoms and molecules. We report the encapsulation of hydrogen fluoride inside C60 using molecular surgery to give the endohedral fullerene HF@C60. The key synthetic step is the closure of the open fullerene cage with the escape of HF minimized. The encapsulated HF molecule moves freely inside the cage and exhibits quantization of its translational and rotational degrees of freedom, as revealed by inelastic neutron scattering and infrared spectroscopy. The rotational and vibrational constants of the encapsulated HF molecules were found to be redshifted relative to free HF. The NMR spectra display a large (1)H-(19)F J coupling typical of an isolated species. The dipole moment of HF@C60 was estimated from the temperature dependence of the dielectric constant at cryogenic temperatures and showed that the cage shields around 75% of the HF dipole.

  4. Environmentally friendly HF (DF) lasers

    NASA Astrophysics Data System (ADS)

    Apollonov, V. V.

    2016-08-01

    Dedicated to the 100th anniversary of the birth of Academician A M Prokhorov, this paper reviews the physics of self-sustained volume discharge without preionization—self-initiated volume discharge (SIVD)—in the working mixtures of non-chain hydrofluoride HF (deuterofluoride (DF)) lasers. The dynamics of SIVD in discharge gaps with different geometries is thoroughly described. The mechanisms for the restriction of current density in a diffuse channel in electric discharges in SF6 and SF6 based mixtures (which determines whether SIVD is possible) are proposed and analyzed using simple models. The most probable mechanisms are the electron impact dissociation of SF6 and other mixture components, electron-ion recombination and electron attachment to vibrationally excited SF6 molecules. Starting from a comparative analysis of the rate coefficients of these processes, it is shown that electron-ion recombination is capable of compensating for electron detachment from negative ions via electron impact. It is also established that SIVD is not only observed in SF6, but also in other strongly electronegative gases. The factors that determine the uniformity of the active medium in non-chain HF (DF) lasers are analyzed. Some special features of non-chain HF (DF) lasers with different apertures operating are carefully examined. Consideration is given to the problem of increasing the aperture and discharge volume of non-chain HF (DF) lasers. Based on our experimental results, the possibility of increasing the energy of such lasers to ~1 kJ and above is shown.

  5. Peripheral blood monocytes from patients with HBV related decompensated liver cirrhosis can differentiate into functional hepatocytes.

    PubMed

    Yan, Li; Han, Ying; Wang, Jingbo; Liu, Jingmei; Hong, Liu; Fan, Daiming

    2007-11-01

    Peripheral blood monocytes (PBMCs) have the potential to differentiate into various progenitor cells. Here we have investigated the differentiation potential of PBMCs derived from patients with HBV related decompensated liver cirrhosis into hepatocyte-like cells. In our clinical trial, the PBMCs from 2 patients were mobilized by the recombinant human granulocyte colony stimulating factor, followed by leukapheresis and transplantation of PBMCs. PBMCs, induced by recombinant human hepatocyte growth factors, were identified by the expression of hepatocyte markers and specific biological functions with biochemical assays in vitro. Patients showed a lasting clinical amelioration for more than one year after transplantation, and hepatocyte-like cells were identified by expressing liver specific genes, synthesizing albumin, urea, aspirate transaminase, and glycogen, which were all similar to the human normal hepatic cell line QZG. Our results clearly demonstrated that mobilized PBMCs from patients with HBV related decompensated liver cirrhosis could differentiate into functional hepatocyte-like cells, indicating the possibility of autologous cell transplantation for treating patients with HBV related decompensated liver cirrhosis.

  6. Entecavir therapy in a hepatitis B-related decompensated cirrhotic patient.

    PubMed

    Muneer, Badar; Testa, Giuliano; Millis, J M; Mohanty, Smruti R

    2008-11-01

    A 58-year-old Arab-American male with HBeAg-negative chronic hepatitis B (HBV), presented with decompensated cirrhosis and a high HBV DNA level. He responded to entecavir with a significant reduction in serum HBV DNA level after 15 weeks of therapy with entecavir. However, he developed a progressive rise in prothrombin time/international normalized ratio (PT/INR) and bilirubin and underwent liver transplantation after receiving 22 weeks of entecavir therapy. Furthermore, with the continued use of combination entecavir and hepatitis B immunoglobulins (HBIG), he showed improvement in his clinical status with a nondetectable serum HBV DNA level 12 weeks after transplantation. He continued to maintain nondetectable serum HBV DNA 2 years following transplantation. To the best of our knowledge, this is the first reported case of a patient with decompensated chronic HBV who responded to entecavir both before and after transplantation without showing any evidence of recurrent HBV. Larger clinical trials are recommended to compare both short-term and long-term efficacy using entecavir among nucleoside-naïve decompensated chronic HBV patients before and after liver transplantation.

  7. Dopant penetration studies through Hf silicate

    NASA Astrophysics Data System (ADS)

    Quevedo-Lopez, M. A.; Visokay, M. R.; Chambers, J. J.; Bevan, M. J.; LiFatou, A.; Colombo, L.; Kim, M. J.; Gnade, B. E.; Wallace, R. M.

    2005-02-01

    We present a study of the penetration of B, P, and As through Hf silicate (HfSixOy) and the effect of N incorporation in Hf silicate (HfSixOyNz) on dopant penetration from doped polycrystalline silicon capping layers. The extent of penetration through Hf silicate was found to be dependent upon the thermal annealing budget for each dopant investigated as follows: B(T⩾950°C/60s), P(T⩾1000°C/20s), and As (T⩾1050°C/60s). We propose that the enhanced diffusion observed for these dopants in HfSixOy, compared with that of SiO2 films, is related to grain boundary formation resulting from HfSixOy film crystallization. We also find that, as in the case of SiO2, N incorporation inhibits dopant (B, P, and As) diffusion through the Hf silicate and thus penetration into the underlying Si substrate. Only B penetration is clearly observed through HfSiON films for anneals at 1050 °C for durations of 10 s or longer. The calculated B diffusivity through the HfSixOyNz layer is D0=5.2×10-15cm2/s.

  8. Influence of Titration of Neurohormonal Antagonists and Blood Pressure Reduction on Renal Function and Decongestion in Decompensated Heart Failure

    PubMed Central

    Wilson, F. Perry; Brisco, Meredith A.; Bellumkonda, Lavanya; Jacoby, Daniel; Coca, Steven G.; Parikh, Chirag R.; Tang, W.H. Wilson; Testani, Jeffrey M.

    2015-01-01

    Background Reduction in systolic blood pressure (SBP reduction) during the treatment of acute decompensated heart failure (ADHF) is strongly and independently associated with worsening renal function (WRF). Our objective was to determine if SBP reduction or titration of oral neurohormonal antagonists during ADHF treatment negatively influences diuresis and decongestion. Methods and Results SBP reduction was evaluated from admission to discharge in consecutive ADHF admissions (n=656). Diuresis and decongestion was examined across a range of parameters such as diuretic efficiency, fluid output, hemoconcentration, and diuretic dose. The average reduction in SBP was 14.4 ± 19.4 mmHg and 77.6% of the population had discharge SBP lower than admission. SBP reduction was strongly associated with WRF (OR=1.9, 95% CI: 1.2-2.9, p=0.004), a finding that persisted after adjusting for parameters of diuresis and decongestion (OR=2.0, 95% CI: 1.3-3.2, p=0.002). However, SBP reduction did not negatively impact diuresis or decongestion (p≥0.25 for all parameters). Uptitration of neurohormonal antagonists occurred in over 50% of admissions and was associated with a modest additional reduction in blood pressure (≤ 5.6 mmHg). Notably, WRF was not increased and diuretic efficiency was significantly improved with the uptitration of neurohormonal antagonists. Conclusions Despite a higher rate of WRF, blood pressure reduction was not associated with worsening of diuresis or decongestion. Furthermore, titration of oral neurohormonal antagonists was actually associated with improved diuresis in this cohort. These results provide reassurance that the guideline recommended titration of chronic oral medication during ADHF hospitalization may not be antagonistic to the short-term goal of decongestion. PMID:26699390

  9. The study of multilayers Fe/Hf and Ni/Hf by slow positron beam technique

    NASA Astrophysics Data System (ADS)

    Tashiro, Mutsumi; Nakajyo, Terunobu; Murashige, Yusuke; Koizumi, Tomoya; Kanazawa, Ikuzo; Komori, Fumio; Soe, We-Hyo; Yamamoto, Ryoichi; Ito, Yasuo

    1997-05-01

    The S-parameters versus the incident positron energy are measured in the Ni/Hf multilayer, thin Hf film, thin Fe film and the bilayer Fe/Hf. We have analyzed the change in vacancy-type defects in these multilayers and thin films with the deposition temperature in the MBE system.

  10. "AVOID"ing harm by a double-edged sword: is there a role for ultrafiltration in heart failure?

    PubMed

    Kazory, Amir

    2016-03-01

    Prior studies comparing ultrafiltration with medical management for acute decompensated heart failure have yielded conflicting results. The AVOID-HF trial was designed as a definitive comparison of optimal ultrafiltration versus optimal diuretic-based medical therapy; unfortunately, the trial was terminated prematurely because of slow recruitment. The results of AVOID-HF nevertheless provide a rationale for well-designed, adequately powered trials to determine whether ultrafiltration has a role in the routine management of acute decompensated heart failure.

  11. Ultrafiltration in patients with decompensated heart failure and diuretic resistance: an Asian centre’s experience

    PubMed Central

    Teo, Loon Yee Louis; Lim, Choon Pin; Neo, Chia Lee; Teo, Lee Wah; Ng, Swee Ling Elaine; Chan, Laura Lihua; Kaushik, Manish; Sim, Kheng Leng David

    2016-01-01

    INTRODUCTION Diuretics are the mainstay of therapy for restoring the euvolaemic state in patients with decompensated heart failure. However, diuretic resistance remains a challenge. METHODS We conducted a retrospective cohort study to examine the efficacy and safety of ultrafiltration (UF) in 44 hospitalised patients who had decompensated heart failure and diuretic resistance between October 2011 and July 2013. RESULTS Among the 44 patients, 18 received UF (i.e. UF group), while 26 received diuretics (i.e. standard care group). After 48 hours, the UF group achieved lower urine output (1,355 mL vs. 3,815 mL, p = 0.0003), greater fluid loss (5,058 mL vs. 1,915 mL, p < 0.0001) and greater weight loss (5.0 kg vs. 1.0 kg, p < 0.0001) than the standard care group. The UF group also had a shorter duration of hospitalisation (5.0 days vs. 9.5 days, p = 0.0010). There were no differences in the incidence of 30-day emergency department visits and rehospitalisations for heart failure between the two groups. At 90 days, the UF group had fewer emergency department visits (0.2 vs. 0.8, p = 0.0500) and fewer rehospitalisations for heart failure (0.3 vs. 1.0, p = 0.0442). Reduction in EQ-5D™ scores was greater in the UF group, both at discharge (2.7 vs. 1.4, p = 0.0283) and 30 days (2.5 vs. 0.3, p = 0.0033). No adverse events were reported with UF. CONCLUSION UF is an effective and safe treatment that can improve the health outcomes of Asian patients with decompensated heart failure and diuretic resistance. PMID:26778634

  12. Simeprevir, daclatasvir and sofosbuvir for hepatitis C virus-infected patients with decompensated liver disease.

    PubMed

    Lawitz, E; Poordad, F; Gutierrez, J A; Kakuda, T N; Picchio, G; Beets, G; Vandevoorde, A; Van Remoortere, P; Jacquemyn, B; Luo, D; Ouwerkerk-Mahadevan, S; Vijgen, L; Van Eygen, V; Beumont, M

    2016-11-23

    Approximately three million individuals in the United States are chronically infected with hepatitis C virus (HCV). Chronic HCV infection may lead to the development of compensated as well as decompensated liver cirrhosis. The Phase II IMPACT study was conducted in HCV genotype 1- or 4-infected cirrhotic patients with portal hypertension or decompensated liver disease and assessed for the first time the combination of the three direct-acting antivirals simeprevir, daclatasvir and sofosbuvir. Treatment-naïve or treatment-experienced adults with Child-Pugh (CP) score <7 (CP A) and evidence of portal hypertension, or CP score 7-9 (CP B), received 12 weeks of simeprevir 150 mg, daclatasvir 60 mg and sofosbuvir 400 mg, once daily. The primary efficacy endpoint was sustained virologic response 12 weeks after end of treatment (SVR12). Pharmacokinetics and safety were also assessed. Overall, 40 patients were enrolled (CP A: 19; CP B: 21). All 40 patients achieved SVR12. At week 8, the mean pharmacokinetic exposure to simeprevir, sofosbuvir, daclatasvir and GS-331007 (sofosbuvir metabolite) was 2.2-, 1.5-, 1.2- and 1.2-fold higher in patients with CP B than CP A, respectively. Grade 1/2 adverse events (AEs) occurred in 26 of 40 (65%) patients. One CP B patient had a Grade 3 AE (gastrointestinal haemorrhage), which was reported as a serious AE but not considered related to study drugs. Treatment for 12 weeks with simeprevir, daclatasvir and sofosbuvir was generally safe and well tolerated, and resulted in 100% of cirrhotic patients with portal hypertension or decompensated liver disease achieving SVR12.

  13. Six cases of hyperosmolar non-ketotic diabetic decompensation in a hospital practice in West Africa.

    PubMed

    Merriman, A

    1975-05-01

    During 1972, of 18 patients admitted to St. Luke's Hospital Anua, Uyo, in S.E. Nigeria, with diabetic metabolic decompensation, six were suffering from hyperglycaemic hyperosmolar non-ketotic coma or pre-coma. The clinical features and treatment of these patients are described. All survived. It is suggested that even when biochemical monitoring is unavailable, the overall mortality could be improved by clinical awareness of this commonly unrecognised condition, combined with replacement therapy using half strength normal saline and modest quantities of insulin and potassium.

  14. [Diuretic resistance and mechanical ventilation in decompensated cor pulmonale: successful treatment by slow continuous ultrafiltration].

    PubMed

    Ries, W; Schenzer, A; Lüken, J; Ries, C; Machraoui, A

    2012-08-01

    We report on a 53-year-old male patient who presented with severe dyspnea at rest and massive volume overload because of decompensated cor pulmonale. Furthermore he suffered from stage 3 chronic kidney disease. As there was diuretics resistance and carbon dioxide narcosis, he had to be intubated and ventilated. The massive volume overload could be successfully treated with slow continuous ultrafiltration (SCUF) with removal of a volume of 27.5 l within 3 days. The SCUF therapy is an effective and gentle method to treat even an excessive volume overload based on diuretics resistance.

  15. Acute hepatitis after amiodarone infusion.

    PubMed

    Fonseca, Paulo; Dias, Adelaide; Gonçalves, Helena; Albuquerque, Aníbal; Gama, Vasco

    2015-10-16

    Acute hepatitis is a very rare, but potentially fatal, adverse effect of intravenous amiodarone. We present a case of an 88-year-old man with history of ischemic dilated cardiomyopathy and severely depressed left ventricular function that was admitted to our coronary care unit with diagnosis of decompensated heart failure and non-sustained ventricular tachycardia. A few hours after the beginning of intravenous amiodarone he developed an acute hepatitis. There was a completely recovery within the next days after amiodarone withdrawn and other causes of acute hepatitis have been ruled out. This case highlights the need for close monitoring of hepatic function during amiodarone infusion in order to identify any potential hepatotoxicity and prevent a fatal outcome. Oral amiodarone is, apparently, a safe option in these patients.

  16. Curative effect of combined lamivudine, adefovir dipivoxil, and stem cell transplantation on decompensated hepatitis B cirrhosis.

    PubMed

    Liu, L; Yan, Y; Zhou, J; Huang, L W; He, C P; Ling, K; Zhou, H C; Wen, Q M; Wang, X M

    2014-02-21

    This study assessed the clinical efficacy of lamivudine and adefovir dipivoxil combined with autologous bone marrow stem cell transplantation as treatment for patients with hepatitis B and decompensated liver cirrhosis. In total, 77 patients with hepatitis B and decompensated liver cirrhosis were randomly divided into two groups. Under general symptomatic and supportive treatment, the patients in group A (37 cases) were treated with lamivudine and adefovir dipivoxil, whereas those in group B (40 cases) were treated with autologous bone marrow stem cell transplantation in combination with lamivudine and adefovir dipivoxil. After 4 weeks of treatment, the liver function indicators and clinical signs and symptoms of the patients in group B improved more significantly than those of patients in group A. Lamivudine and adefovir dipivoxil in combination with autologous bone marrow stem cell transplantation effectively prevented hepatitis B virus infection and bone marrow stem cell damage. This combination treatment facilitates the differentiation of bone marrow stem cells into normal liver cells to restore liver structure and improve liver function, thereby improving the quality of life of patients.

  17. Predictive monitoring for respiratory decompensation leading to urgent unplanned intubation in the neonatal intensive care unit

    PubMed Central

    Clark, Matthew T.; Vergales, Brooke D.; Paget-Brown, Alix O.; Smoot, Terri J.; Lake, Douglas E.; Hudson, John L.; Delos, John B.; Kattwinkel, John; Moorman, J. Randall

    2013-01-01

    Background Infants admitted to the neonatal intensive care unit (NICU), and especially those born with very low birth weight (VLBW; <1500 grams), are at risk for respiratory decompensation requiring endotracheal intubation and mechanical ventilation. Intubation and mechanical ventilation are associated with increased morbidity, particularly in urgent unplanned cases. Methods We tested the hypothesis that the systemic response associated with respiratory decompensation can be detected from physiological monitoring, and that statistical models of bedside monitoring data can identify infants at increased risk of urgent, unplanned intubation. We studied 287 VLBW infants consecutively admitted to our NICU and found 96 events in 51 patients, excluding intubations occurring within 12 hours of a previous extubation. Results In order of importance in a multivariable statistical model, we found the characteristics of reduced O2 saturation, especially as heart rate was falling, increased heart rate correlation with respiratory rate, and the amount of apnea all were significant independent predictors. The predictive model, validated internally by bootstrap, had receiver-operating characteristic area of 0.84 ± 0.04. Conclusions We propose that predictive monitoring in the NICU for urgent unplanned intubation may improve outcomes by allowing clinicians to intervene non-invasively before intubation is required. PMID:23138402

  18. Entecavir-Associated Thrombocytopenia in a Decompensated Cirrhotic Patient: A Case Report and Literature Review.

    PubMed

    Fan, Xiaoli; Chen, Liyu; Yang, Jingyu; Feng, Ping

    2016-03-01

    Drug-associated thrombocytopenia is common and curable, but there were few reports about entecavir-associated thrombocytopenia.We report here a case of a 65-year-old female patient with decompensated cirrhosis. The patient developed a fatal thrombocytopenia while under entecavir treatment. After she received entecavir treatment for 4 days, the patient's platelet count dropped significantly to 1 × 10/L, accompanied with a manifestation of mild sclera bleeding. All diagnostic data suggested an entecavir-induced immunological thrombocytopenia. The patient eventually fully recovered after treated with daily intravenous immunoglobulin infusions.Actually, there were only a handful of reports that children or adults with chronic hepatitis B developed a thrombocytopenia due to nucleoside analogue medication. Timeliness of intravenous immunoglobulin infusion could stop the fatal bleeding for patients with entecavir-associated immunological thrombocytopenia. Hence, early diagnosis and treatment are recommended. Our case suggested that the platelet count should be monitored regularly in patients with decompensated cirrhosis with underline immunological disease while treated with ETV.

  19. Levosimendan: a calcium-sensitizing agent for the treatment of patients with decompensated heart failure.

    PubMed

    Lehtonen, Lasse

    2004-09-01

    Levosimendan is a new inodilator. Its mechanism of action includes calcium sensitization of contractile proteins and the opening of adenosine triphosphate-dependent K channels. The combination of positive inotropy with anti-ischemic effects of K-channel opening offers potential benefits in comparison with currently available intravenous inotropes, which are contraindicated in patients with ongoing myocardial ischemia. Levosimendan has been extensively studied in various animal models of heart failure, in which the drug has increased contractility without adverse effects on diastolic function. These results have been repeated in patients with heart failure, in whom levosimendan dose-dependently increases cardiac output and reduces pulmonary capillary wedge pressure. The active metabolite of levosimendan (OR-1896) significantly prolongs the duration of the hemodynamic effects of the therapeutic 24-hour levosimendan infusion. Levosimendan has been studied in two major trials with decompensated patients (LIDO and RUSSLAN), in which it showed outcome benefits in comparison with dobutamine and placebo, respectively. A third comparative study (CASINO) recently suggested mortality benefits with levosimendan over placebo and dobutamine. Currently, two large prospective trials (SURVIVE and REVIVE) in patients who are hospitalized because of worsening heart failure are underway. These trials will conclusively prove whether levosimendan should be added to the standard treatment in patients who are hospitalized because of cardiac decompensation.

  20. Organ protection possibilities in acute heart failure.

    PubMed

    Montero-Pérez-Barquero, M; Morales-Rull, J L

    2016-04-01

    Unlike chronic heart failure (HF), the treatment for acute HF has not changed over the last decade. The drugs employed have shown their ability to control symptoms but have not achieved organ protection or managed to reduce medium to long-term morbidity and mortality. Advances in our understanding of the pathophysiology of acute HF suggest that treatment should be directed not only towards correcting the haemodynamic disorders and achieving symptomatic relief but also towards preventing organ damage, thereby counteracting myocardial remodelling and cardiac and extracardiac disorders. Compounds that exert vasodilatory and anti-inflammatory action in the acute phase of HF and can stop cell death, thereby boosting repair mechanisms, could have an essential role in organ protection.

  1. Acute massive mitral regurgitation from prosthetic valve dysfunction.

    PubMed Central

    Cooper, D K; Sturridge, M F

    1976-01-01

    Two cases of prosthetic valve dysfunction resulting in acute massive mitral regurgitation are reported; emergency operation was successful in both cases. Survival following complete dislodgement of the occluder of a disc valve, as occurred in one case, does not appear to have been reported before. The diffculty in diagnosis of sudden cardiac decompensation in patients with prosthetic valves is stressed, as is the need for urgent operation. Images PMID:973894

  2. What are the effects of hypertonic saline plus furosemide in acute heart failure?

    PubMed

    Zepeda, Patricio; Rain, Carmen; Sepúlveda, Paola

    2015-08-27

    In search of new therapies to solve diuretic resistance in acute heart failure, the addition of hypertonic saline has been proposed. Searching in Epistemonikos database, which is maintained by screening 30 databases, we identified two systematic reviews including nine pertinent randomized controlled trials. We combined the evidence and generated a summary of findings following the GRADE approach. We concluded hypertonic saline associated with furosemide probably decrease mortality, length of hospital stay and hospital readmission in patients with acute decompensated heart failure.

  3. Endocardial Endothelial Dysfunction Progressively Disrupts Initially Anti then Pro-Thrombotic Pathways in Heart Failure Mice

    PubMed Central

    Schoner, Amanda; Tyrrell, Christina; Wu, Melinda; Gelow, Jill M.; Hayes, Alicia A.; Lindner, Jonathan R.; Thornburg, Kent L.; Hasan, Wohaib

    2015-01-01

    Objective An experimental model of endocardial thrombosis has not been developed and endocardial endothelial dysfunction in heart failure (HF) is understudied. We sought to determine whether disruption of the endothelial anti-coagulant activated protein C (APC) pathway in CREBA133 HF mice promotes endocardial thrombosis in the acute decompensated phase of the disease, and whether alterations in von Willebrand factor (vWF) secretion from HF endocardium reduces thrombus formation as HF stabilizes. Approach and results Echocardiography was used to follow HF development and to detect endocardial thrombi in CREBA133 mice. Endocardial thrombi incidence was confirmed with immunohistochemistry and histology. In early and acute decompensated phases of HF, CREBA133 mice had the highest incidence of endocardial thrombi and these mice also had a shorter tail-bleeding index consistent with a pro-thrombotic milieu. Both APC generation, and expression of receptors that promote APC function (thrombomodulin, endothelial protein C receptor, protein S), were suppressed in the endocardium of acute decompensated HF mice. However, in stable compensated HF mice, an attenuation occurred for vWF protein content and secretion from endocardial endothelial cells, vWF-dependent platelet agglutination (by ristocetin), and thrombin generation on the endocardial surface. Conclusions CREBA133 mice develop HF and endocardial endothelial dysfunction. Attenuation of the anti-coagulant APC pathway promotes endocardial thrombosis in early and acute decompensated phases of HF. However, in stable compensated HF mice, disruptions in endothelial vWF expression and extrusion may actually reduce the incidence of endocardial thrombosis. PMID:26565707

  4. EXAFS determination of Hf localization in HDDR Nd Fe B Hf alloys

    NASA Astrophysics Data System (ADS)

    Torres, C. E. Rodríguez; Fernández van Raap, M. B.; Sánchez, F. H.; Pasquevich, A. F.

    2005-05-01

    The local structure around Hf in Nd 15.78Fe 76.3-xHf xB 7.8 ( x=0.1 and 0.2) submitted to conventional and solid hydrogenation-disproportionation-desorption-recombination (HDDR) sequence was studied by extended X-ray absorption fine structure (EXAFS) in order to understand the relation between the presence of Hf and magnetic anisotropy found only in solid-HDDR samples. EXAFS results show that Hf is not in the Nd 2Fe 14B structure but incorporated into a local atomic arrangement (HfB ClNa-type) which is the same for as-cast, solid and conventional HDDR samples. It is concluded that the magnetic anisotropy induced by Hf addition to NdFeB alloys must be related to microstructural features.

  5. On the road to HF mitigation

    SciTech Connect

    Van Zele, R.L.; Diener, R. )

    1990-07-01

    Two components were investigated as a part of tests run by Industry Cooperative HF Mitigation/Assessment Program (ICHMAP). This paper discusses how the test program included a vapor barrier component and an ambient impact assessment component.

  6. Autologous Peripheral Blood Stem Cell Transplantation Improves Portal Hemodynamics in Patients with Hepatitis B Virus-related Decompensated Cirrhosis

    PubMed Central

    Deng, Qinzhi; Cai, Ting; Zhang, Shun; Hu, Airong; Zhang, Xingfen; Wang, Yinyin; Huang, Jianrong

    2015-01-01

    Background: Chronic hepatitis B virus (HBV) infection may eventually lead to decompensated liver cirrhosis, which is a terminal illness. Objectives: The aim of this study was to investigate the therapeutic efficacy of autologous peripheral blood stem cell (APBSC) transplantation to improve portal vein hemodynamics in patients with HBV-related decompensated cirrhosis. Patients and Methods: This prospective study included 68 hospitalized patients who were diagnosed with HBV-related decompensated cirrhosis. These patients were divided into two groups: the transplantation group included 33 patients, while the control group included 35. Both groups received conventional medical treatment simultaneously, and APBSC transplantation was performed on the patients in the transplantation group. We evaluated the effects of APBSC transplantation on postoperative liver function using the following indices: total bilirubin, serum prothrombin and albumin, spleen size, and portal vein hemodynamics. Postoperatively, all of the patients were followed up at 24, 36, and 48 weeks. Results: The transplantation group had no serious reactions. Compared with the control group, albumin and prothrombin activity in the transplantation group was significantly improved at 24, 36, and 48 weeks after the procedure, and spleen length and portal vein diameter were substantially reduced at 48 weeks. The velocity of peak portal vein blood flow and mean maximum portal vein blood flow were greatly increased in the APBSC transplantation group at 36 and 48 weeks, respectively; however, there was also decreased portal vein diameter, which reduced portal vein pressure in patients with HBV-related decompensated cirrhosis. Conclusions: APBSC transplantation greatly benefits HBV-linked decompensated cirrhosis patients and should be recommended in clinical practice. PMID:26977164

  7. Refiners discuss HF alkylation process and issues

    SciTech Connect

    Not Available

    1992-04-06

    Safety and oxygenate operations made HF alkylation a hot topic of discussion at the most recent National Petroleum Refiners Association annual question and answer session on refining and petrochemical technology. This paper provides answers to a variety of questions regarding the mechanical, process, and safety aspects of the HF alkylation process. Among the issues discussed were mitigation techniques, removal of oxygenates from alkylation unit feed, and amylene alkylation.

  8. On the road to HF mitigation

    SciTech Connect

    VanZele, R.L.; Diener, R. )

    1990-06-01

    The hazards of hydrogen fluoride (HF) have long been recognized and industry performance reflects sound operating practices. However, full-scale industry-sponsored HF release test conducted at the U.S. Department of Energy (DOE) test site in 1986 caused concern in view of HF's toxicity. Ambient impacts were greater than anticipated. And diking, a primary mitigation technique, proved ineffective for releases of pressurized superheated HF. In partial response to these new technical data, an ad-hoc three-component Industry Cooperative Hydrogen Fluoride Mitigation Assessment Program (ICHMAP) was begun in late 1987 to study and test techniques for mitigating accidental releases of HF and alkylation unit acid (AUA) and to enhance capabilities to estimate ambient impacts from such releases. AUA is a mixture of HF and hydrocarbons. The program's mitigation components have recently been completed while work on the impact assessment component is nearing completion. This article describes the program and summarizes the objective, scope of work, structure, and conclusions from the program's two mitigation components. In addition, the objectives and scope of work of the impact assessment components are described.

  9. Target organ damage in acute heart failure.

    PubMed

    Casado Cerrada, J; Zabaleta Camino, J P; Fontecha Ortega, M

    2016-03-01

    Acute heart failure is a prognostic factor due to its high mortality during the acute phase and the increased frequency of medium to long-term adverse events. The pathophysiological mechanisms triggered during these exacerbations can persist after reaching clinical stability, remaining even after the acute episode has ended. A certain degree of neurohormonal activation, oxidative stress, apoptosis and inflammation (among other conditions) can therefore persist, resulting in organ damage, not just of the myocardium but likely the entire cardiovascular apparatus. This new insight into the persistence of harmful mechanisms that last beyond the exacerbations could be the start of a change in perspective for developing new therapeutic strategies that seek an overall control of hemodynamic and congestive changes that occur during acute decompensated heart failure and changes that remain after achieving clinical stability.

  10. Upscaling cardiac assist devices in decompensated heart failure: Choice of device and its timing.

    PubMed

    Mishra, Sundeep

    2016-04-01

    Advanced heart failure is a heterogeneous condition unified by a very high mortality unless right treatment is instituted at the right time. The first step is understanding the mechanism leading to instability: hemodynamic or ischemic. Right kind of therapy; drugs (ionotropic) or IABP or other cardiac assist devices should be chosen according to mechanism of insult as well as degree of insult. Drugs such as ionotropes are effective only in very early course but if the decompensation has progressed beyond a certain point device such as IABP may be effective but again only early in the course when CPO? 0.6. Beyond a certain point, even IABP may not be effective: here only Impella (2.5, CP or 5) or Tandem Heart may be effective. However, beyond a certain point CPO<0.53, even these devices may not be effective. Thus crux of the matter is choice of a right device/drug and timing of its institution.

  11. Treatment of patients with HBV-related decompensated cirrhosis and liver transplanted patients.

    PubMed

    Roche, Bruno; Samuel, Didier

    2013-08-01

    Antiviral therapy using newer nucleos(t)ide analogs with lower resistance rates could suppress hepatitis B virus (HBV) replication, improve liver function in patients with compensated or decompensated cirrhosis, delay or obviate liver transplantation in some patients, and reduce the risk of HBV recurrence. Some form of HBV prophylaxis needs to be continued indefinitely posttransplant. However, in patients with a low-risk of HBV recurrence it is possible to discontinue hepatitis B immunoglobulins and maintain long-term nucleos(t)ide analog therapy. Currently, treatment of posttransplantation hepatitis B is a less important clinical problem than it was historically because effective antiviral therapies exist to rescue patients who failed initial prophylaxis.

  12. Splenectomy prior to antiviral therapy in patients with hepatitis C virus related decompensated cirrhosis.

    PubMed

    Ji, Fanpu; Zhang, Shu; Huang, Na; Deng, Hong; Li, Zongfang

    2013-01-01

    Patients with hepatitis C virus-related decompensated cirrhosis can benefit from interferon-based antiviral therapy, but the common complication of cytopenia is a contraindication for this treatment. Splenectomy prior to interferon therapy may alleviate this problem. To investigate whether splenectomy improves the efficacy of antiviral therapy, 13 interferon-naïve hepatitis C virus decompensated cirrhotic patients underwent splenectomy between January 2008 and January 2011, followed 1-3 months later by an interferon-based therapeutic regimen (pegylated/standard interferon-α combined with ribavirin for 48 weeks). Ten (76.9%) of the patients developed postoperative complications, which included minor portal vein thrombosis (2/13, 15.4%) and transient ascites (8/13, 61.5%). At one-month post-splenectomy, the patients showed significantly increased platelet (pre-surgery: 48.2±15.9 vs. 186.0±70.6×10(3)μL(-1), p<0.001) and leukocyte (2.1±0.5 vs. 5.7±1.4×10(3)μL(-1), p<0.001) counts. Eight (61.5%) of the patients achieved sustained virological response, including all HCV genotype 2a-infected patients (4/4, 100%) and some of the genotype 1b-infected patients (4/9, 44.4%). Temporary interferon-α suspension was required for one patient to address severe intestinal infection. These results indicate that splenectomy prior to interferon-based therapy was safe and may facilitate adherence to subsequent antiviral therapy in selected HCV cirrhotic patients with portal hypertension and hypersplenism.

  13. Death from undetected acute myocardial infarction secondary to coronary artery dissection after blunt thoracic trauma.

    PubMed

    Puanglumyai, Supot; Thamtakerngkit, Somboon; Lekawanvijit, Suree

    2016-01-01

    Blunt thoracic trauma is a common occurrence in automobile accidents. Acute myocardial infarction (AMI) caused by coronary dissection following blunt thoracic trauma is rare. We report a case of healthy 24-year-old man with a history of blunt thoracic injury with subsequent undetected AMI who died of acute decompensated heart failure 4 days after the insult. The autopsy findings showed a 90% luminal narrowing of the left anterior descending coronary artery by dissecting hematoma, 3 cm in length. The myocardium revealed transmural myocardial infarction affecting apex, most part of left ventricular free wall, and interventricular septum. Both lungs were heavy, wet, and noncrepitant. Histological findings of the infarcted myocardium were consistent with 3-5 days post-AMI. Sections from both lungs revealed massive pulmonary edema, reflecting acute decompensated heart failure following a large AMI secondary to coronary dissection. Blunt thoracic trauma may obscure typical chest pain associated with cardiac ischemia especially in cases with a high tolerance for pain.

  14. HF Accelerated Electron Fluxes, Spectra, and Ionization

    NASA Astrophysics Data System (ADS)

    Carlson, Herbert C.; Jensen, Joseph B.

    2015-10-01

    Wave particle interactions, an essential aspect of laboratory, terrestrial, and astrophysical plasmas, have been studied for decades by transmitting high power HF radio waves into Earth's weakly ionized space plasma, to use it as a laboratory without walls. Application to HF electron acceleration remains an active area of research (Gurevich in Usp Fizicheskikh Nauk 177(11):1145-1177, 2007) today. HF electron acceleration studies began when plasma line observations proved (Carlson et al. in J Atmos Terr Phys 44:1089-1100, 1982) that high power HF radio wave-excited processes accelerated electrons not to ~eV, but instead to -100 times thermal energy (10 s of eV), as a consequence of inelastic collision effects on electron transport. Gurevich et al (J Atmos Terr Phys 47:1057-1070, 1985) quantified the theory of this transport effect. Merging experiment with theory in plasma physics and aeronomy, enabled prediction (Carlson in Adv Space Res 13:1015-1024, 1993) of creating artificial ionospheres once ~GW HF effective radiated power could be achieved. Eventual confirmation of this prediction (Pedersen et al. in Geophys Res Lett 36:L18107, 2009; Pedersen et al. in Geophys Res Lett 37:L02106, 2010; Blagoveshchenskaya et al. in Ann Geophys 27:131-145, 2009) sparked renewed interest in optical inversion to estimate electron spectra in terrestrial (Hysell et al. in J Geophys Res Space Phys 119:2038-2045, 2014) and planetary (Simon et al. in Ann Geophys 29:187-195, 2011) atmospheres. Here we present our unpublished optical data, which combined with our modeling, lead to conclusions that should meaningfully improve future estimates of the spectrum of HF accelerated electron fluxes. Photometric imaging data can significantly improve detection of emissions near ionization threshold, and confirm depth of penetration of accelerated electrons many km below the excitation altitude. Comparing observed to modeled emission altitude shows future experiments need electron density profiles

  15. Improved techniques for monitoring the HF spectrum

    NASA Astrophysics Data System (ADS)

    Giesbrecht, James E.; Clarke, Russell; Abbott, Derek

    2004-03-01

    A critical review of contemporary papers on modulation recognition, signal separation, and Single Station Location (SSL) is described in the context of High-Frequency (HF) radio-communications. High-frequency communications is undergoing resurgence despite advances in long-range satellite communication systems. Defense agencies are using the HF spectrum for backup communications as well as for spectrum surveillance applications. Spectrum management organizations are monitoring the HF spectrum to control and enforce licensing. This type of activity usually requires a system that is able to determine the location of a source of transmissions, separate valid signals from interferers and noise, and characterize signals-of-interest (SOI). The immediate aim is to show that commercial-off-the-shelf (COTS) equipment can be used to locate HF transmission sources, enhance SOIs and reject interference, and recognize signal types. The described work on single-station-location (SSL), signal separation, and modulation recognition is contributing to these goals. This paper describes the overall objectives and some of the disadvantages and benefits of various schemes for single-station-location (SSL), signal separation, and modulation recognition. It also proposes new approaches that may relieve shortcomings of existing methods -- including selection of benchmarks or modulations for various transmission scenarios and propagation modes, and use of multiple digital receivers or compression techniques to improve modulation recognition, signal separation, and location of HF emitters.

  16. Interdisciplinary Peripartum Management of Acute Respiratory Distress Syndrome with Extracorporeal Membrane Oxygenation – a Case Report and Literature Review

    PubMed Central

    Weyrich, J.; Bogdanski, R.; Ortiz, J. U.; Kuschel, B.; Schneider, K. T. M.; Lobmaier, S. M.

    2016-01-01

    Extracorporeal membrane oxygenation (ECMO) is increasingly used for the management of acute severe cardiac and respiratory failure. One of the indications is acute respiratory distress syndrome (ARDS) for which, in some severe cases, ECMO represents the only possibility to save lives. We report on the successful long-term use of ECMO in a postpartum patient with recurrent pulmonary decompensation after peripartum uterine rupture with extensive blood loss. PMID:27065489

  17. Adaptive tracking of narrowband HF channel response

    NASA Astrophysics Data System (ADS)

    Arikan, F.; Arikan, O.

    2003-12-01

    Estimation of channel impulse response constitutes a first step in computation of scattering function, channel equalization, elimination of multipath, and optimum detection and identification of transmitted signals through the HF channel. Due to spatial and temporal variations, HF channel impulse response has to be estimated adaptively. Based on developed state-space and measurement models, an adaptive Kalman filter is proposed to track the HF channel variation in time. Robust methods of initialization and adaptively adjusting the noise covariance in the system dynamics are proposed. In simulated examples under good, moderate and poor ionospheric conditions, it is observed that the adaptive Kalman filter based channel estimator provides reliable channel estimates and can track the variation of the channel in time with high accuracy.

  18. The ADMX-HF (High Frequency) Experiment

    NASA Astrophysics Data System (ADS)

    Lehnert, K. W.

    2013-04-01

    For many years, the Axion Dark Matter eXperiment (ADMX) has searched for dark-matter axions by their resonant conversion to photons in a high-Q microwave cavity embedded in a strong magnetic field; to date focusing on the ˜1 GHz range, or ma˜ few micro-eV. A second platform, ADMX-HF is now being constructed at Yale University which will focus on technology development and a first look at data in the ˜10 GHz range. Consisting of a 9T superconducting magnet (40 cm long x 14 cm diameter), a dilution refrigerator and a quantum-limited receiver based on Josephson Parametric Amplifiers (JPA) ADMX-HF is projected to achieve sensitivity within the axion model band, despite its smaller volume than ADMX. ADMX-HF is a collaboration of Yale, JILA/Colorado, UC Berkeley and LLNL, and by agreement will create a unified data set with ADMX.

  19. HF Radio Wave Production of Artificial Ionospheres

    NASA Astrophysics Data System (ADS)

    Carlson, Herbert

    In 1993 it was predicted that artificial ionospheres would be produced by high power HF radio waves, once HF transmitters approached a GWatt ERP. When that threshold was very recently achieved, such production was indeed detected and published at two high latitude high power HF facilities. Here we review: the first-principles logic behind that prediction, which aspects of such production are critically dependent on magnetic latitude, and which aspects of such production depend only on physical parameters independent of latitude. These distinctions follow directly from decomposition of the problem of ionization production into its components of: radio-wave propagation, wave-particle interactions, electron transport, and quantitative elastic/inelastic cross-sections. We outline this analysis to show that, within the context of early observations, the production of ionization is inevitable, and only a question of competing instability thresholds, and scale of ionization production. This illustrates complimentary aeronomy and plasma physics to advance understanding of both.

  20. Role of albumin in diseases associated with severe systemic inflammation: Pathophysiologic and clinical evidence in sepsis and in decompensated cirrhosis.

    PubMed

    Artigas, Antonio; Wernerman, Jan; Arroyo, Vicente; Vincent, Jean-Louis; Levy, Mitchell

    2016-06-01

    The metabolism of albumin in inflammatory states such as sepsis or major surgery is complex and still not well characterized. Nevertheless, in inflammatory states, albumin synthesis has been observed to increase. By contrast, in decompensated cirrhosis, a disease characterized by systemic inflammation, albumin synthesis by the liver may decrease to 30% to 50% of normal values. Furthermore, in these conditions, there are high capillary leakage and altered albumin kinetics. The discussion regarding the effect of exogenous albumin administration on intravascular volume in inflammatory states should therefore address albumin turnover. To add complexity to our understanding of the effects of albumin, there are many data indicating that the therapeutic action of albumin is mediated not only through the impact on plasma volume expansion but also through a modulatory effect on inflammation and oxidative stress. All these characteristics are relevant to diseases associated with systemic inflammation including sepsis and decompensated cirrhosis.

  1. Decompensation: A Novel Approach to Accounting for Stress Arising From the Effects of Ideology and Social Norms.

    PubMed

    Riggs, Damien W; Treharne, Gareth J

    2017-01-01

    To date, research that has drawn on Meyer's (2003) minority stress model has largely taken for granted the premises underpinning it. In this article we provide a close reading of how "stress" is conceptualized in the model and suggest that aspects of the model do not attend to the institutionalized nature of stressors experienced by people with marginalized identities, particularly lesbian, gay, bisexual, and transgender individuals. As a counter to this, we highlight the importance of a focus on the effects of ideology and social norms in terms of stress, and we argue why an intersectional approach is necessary to ensure recognition of multiple axes of marginalization and privilege. The article then outlines the concept of decompensation and suggests that it may offer one way to reconsider the effects of ideology and social norms. The decompensation approach centers on the need for social change rather than solely relying on individuals to be resilient.

  2. Effective control of relapsing disseminated intravascular coagulation in a patient with decompensated liver cirrhosis by recombinant soluble thrombomodulin.

    PubMed

    Hasebe, Takumu; Sawada, Koji; Nakajima, Shunsuke; Maeda, Shigeaki; Abe, Masami; Suzuki, Yasuaki; Ohtake, Takaaki; Hasebe, Chitomi; Fujiya, Mikihiro; Kohgo, Yutaka

    2014-01-01

    A 70-year-old Japanese man was hospitalized for expanding purpura and chronic disseminated intravascular coagulation (DIC) caused by decompensated liver cirrhosis. As there are no effective treatments for chronic DIC caused by liver cirrhosis, we decided to administer recombinant human soluble thrombomodulin (rhsTM) after he provided informed consent. The DIC was rapidly improved; however, the purpura and coagulopathy recurred after two months, and repeated rhsTM treatments were required. The rhsTM treatment sufficiently controlled the coagulopathy for two years, without any complications, including bleeding. This is the first report demonstrating that rhsTM can be administered safely and repeatedly to a patient with decompensated liver cirrhosis, and that it appears to be associated with a favorable outcome.

  3. Decompensated lamivudine-resistant hepatitis B virus-related cirrhosis treated successfully with adefovir dipivoxil allowing surgery for hepatocellular carcinoma.

    PubMed

    Takamura, Masaaki; Ichida, Takafumi; Ohkoshi, Shogo; Tsubata, Shunsuke; Osaki, Akihiko; Aoyagi, Tomoya; Nomoto, Minoru; Uehara, Kazuhiro; Terada, Haruo; Aoyagi, Yutaka

    2007-01-01

    We describe a 64-year-old man with decompensated hepatitis B virus (HBV)-related cirrhosis who became resistant to lamivudine. He was started on adefovir at 10 mg daily while continuing lamivudine therapy. Several months later, his liver function improved and subsequently his ascites disappeared. The serum HBV-DNA level became undetectable 11 months later. Twenty months after the start of additional treatment with adefovir, one hepatocellular carcinoma (HCC) was detected, and the patient underwent a successful hepatectomy. Our findings suggest that the addition of adefovir to ongoing lamivudine therapy is useful for improving liver function in patients with decompensated lamivudine-resistant HBV-related cirrhosis, allowing surgery for HCC.

  4. Removal of uranium from aqueous HF solutions

    DOEpatents

    Pulley, Howard; Seltzer, Steven F.

    1980-01-01

    This invention is a simple and effective method for removing uranium from aqueous HF solutions containing trace quantities of the same. The method comprises contacting the solution with particulate calcium fluoride to form uranium-bearing particulates, permitting the particulates to settle, and separting the solution from the settled particulates. The CaF.sub.2 is selected to have a nitrogen surface area in a selected range and is employed in an amount providing a calcium fluoride/uranium weight ratio in a selected range. As applied to dilute HF solutions containing 120 ppm uranium, the method removes at least 92% of the uranium, without introducing contaminants to the product solution.

  5. General concepts of modern HF communications

    NASA Astrophysics Data System (ADS)

    Aarons, Jules

    Both conceptual and hardware advancements have led to substantial systems developments in military HF communications; the former encompass coding and error correction techniques for security, in order to minimize propagation and interference, while the latter prominently include digital equipment permitting the selection of a frequency for a particular path and propagation mode, as well as modulation selection. Propagation-related advancements involve better statistical models as well as advancements in short-term forecasting methods responsive to changes in solar-geophysical parameters. Adaptive HF systems have been developed for meteor-scatter radio communications.

  6. Learning from recent trials and shaping the future of acute heart failure trials

    PubMed Central

    Mentz, Robert J.; Felker, Gary Michael; Ahmad, Tariq; Peacock, William Frank; Pitt, Bertram; Fiuzat, Mona; Maggioni, Aldo P.; Gheorghiade, Mihai; Ando, Yuki; Pocock, Stuart J.; Zannad, Faiez; O’Connor, Christopher M.

    2014-01-01

    The last decade of acute heart failure (HF) research is characterized by disappointments in large phase 2 and 3 pharmacologic studies of therapeutics including calcium-sensitizing agents and antagonists of endothelin, vasopressin, and adenosine. As a result, pharmacologic management for acute HF has changed little in recent years, and adverse event rates remain higher than in chronic HF. Despite neutral results in many acute HF trials, recent studies including RELAX-AHF, ASTRONAUT, and PRONTO have highlighted the role of appropriate timing of patient enrollment, targeting the “right” patients, and selecting appropriate end points and sites. We describe lessons learned from recent trials in acute HF and outline strategies to improve the potential for success in future trials. This review is based on discussions between scientists, clinical trialists, and regulatory representatives at the 9th Global Cardio Vascular Clinical Trialists Forum in Paris, France, from November 30 to December 1, 2012. PMID:24093841

  7. Low Temperature Silicon Surface Cleaning by HF Etching/Ultraviolet Ozone Cleaning (HF/UVOC) Method (I)—Optimization of the HF Treatment—

    NASA Astrophysics Data System (ADS)

    Suemitsu, Maki; Kaneko, Tetsuya; Miyamoto, Nobuo

    1989-12-01

    Several variations of fluoric acid (HF) treatments of silicon substrates were examined for their adaptability as a pretreatment method for a silicon epitaxy process. Treatments with and without distilled, deionized (DI) water rinse, of different HF concentrations, and of different methods of HF supply were tested and their residual carbonic impurity contents were measured using RHEED. As a result, HF treatments by themselves were found to be insufficient in passivating the surface dangling bonds irrespective of the method of HF supply: dipping into the solution or exposure to the vapor. The optimum procedure of HF treatment thus proposed is a succession of (a) HF dipping, (b) DI-water rinsing, (c) nitrogen-gas blowing, and (d) UV-ozone cleaning.

  8. Nanometer-scale crystallization of thin HfO2 films studied by HF-chemical etching

    NASA Astrophysics Data System (ADS)

    Fujii, Shinji; Miyata, Noriyuki; Migita, Shinji; Horikawa, Tsuyoshi; Toriumi, Akira

    2005-05-01

    We used a HF-chemical etching process to examine crystalline structures in thin HfO2 films grown by metal organic chemical vapor deposition at 350-550°C. Nanometer-scale crystalline HfO2 nuclei were identified from all the HfO2 films. The nucleus density exponentially increased with increasing deposition temperature, but the diameter of the nuclei did not depend on the deposition temperature. We propose that the crystallization of thin HfO2 film during growth proceeds in a patchwork process with the increase of the crystalline HfO2 nuclei.

  9. Cardiac p300 Is Involved in Myocyte Growth with Decompensated Heart Failure

    PubMed Central

    Yanazume, Tetsuhiko; Hasegawa, Koji; Morimoto, Tatsuya; Kawamura, Teruhisa; Wada, Hiromichi; Matsumori, Akira; Kawase, Yosuke; Hirai, Maretoshi; Kita, Toru

    2003-01-01

    A variety of stresses on the heart initiate a number of subcellular signaling pathways, which finally reach the nuclei of cardiac myocytes and cause myocyte hypertrophy with heart failure. However, common nuclear pathways that lead to this state are unknown. A zinc finger protein, GATA-4, is one of the transcription factors that mediate changes in gene expression during myocardial-cell hypertrophy. p300 not only acts as a transcriptional coactivator of GATA-4, but also possesses an intrinsic histone acetyltransferase activity. In primary cardiac myocytes derived from neonatal rats, we show that stimulation with phenylephrine increased an acetylated form of GATA-4 and its DNA-binding activity, as well as expression of p300. A dominant-negative mutant of p300 suppressed phenylephrine-induced nuclear acetylation, activation of GATA-4-dependent endothelin-1 promoters, and hypertrophic responses, such as increase in cell size and sarcomere organization. In sharp contrast to the activation of cardiac MEK-1, which phosphorylates GATA-4 and causes compensated hypertrophy in vivo, p300-mediated acetylation of mouse cardiac nuclear proteins, including GATA-4, results in marked eccentric dilatation and systolic dysfunction. These findings suggest that p300-mediated nuclear acetylation plays a critical role in the development of myocyte hypertrophy and represents a pathway that leads to decompensated heart failure. PMID:12724418

  10. A Signal Processing Approach for Detection of Hemodynamic Instability before Decompensation

    PubMed Central

    Belle, Ashwin; Ansari, Sardar; Spadafore, Maxwell; Convertino, Victor A.; Ward, Kevin R.; Derksen, Harm; Najarian, Kayvan

    2016-01-01

    Advanced hemodynamic monitoring is a critical component of treatment in clinical situations where aggressive yet guided hemodynamic interventions are required in order to stabilize the patient and optimize outcomes. While there are many tools at a physician’s disposal to monitor patients in a hospital setting, the reality is that none of these tools allow hi-fidelity assessment or continuous monitoring towards early detection of hemodynamic instability. We present an advanced automated analytical system which would act as a continuous monitoring and early warning mechanism that can indicate pending decompensation before traditional metrics can identify any clinical abnormality. This system computes novel features or bio-markers from both heart rate variability (HRV) as well as the morphology of the electrocardiogram (ECG). To compare their effectiveness, these features are compared with the standard HRV based bio-markers which are commonly used for hemodynamic assessment. This study utilized a unique database containing ECG waveforms from healthy volunteer subjects who underwent simulated hypovolemia under controlled experimental settings. A support vector machine was utilized to develop a model which predicts the stability or instability of the subjects. Results showed that the proposed novel set of features outperforms the traditional HRV features in predicting hemodynamic instability. PMID:26871715

  11. [Two post-traumatic "Gilliatt-Sumner hands" from decompensation of thoracic outlet syndrome].

    PubMed

    Figiel, S; Dubuisson, A

    2011-02-01

    The clinical picture of hand atrophy related to a cervical rib has been well described in 1970 by Gilliatt and Sumner. These authors reported a series of nine patients whose motor status was stabilized following decompressive surgery of the brachial plexus. We report two young patients decompensating a predisposed thoracic outlet (rudimentary cervical rib), following a scapular or cervical trauma. After several years of neck and arm painful complaints, the two patients progressively developed hand atrophy. One patient had been operated both at cervical (double discectomy and disc prosthesis) and elbow (ulnar nerve neurolysis) levels, before the diagnosis of thoracic outlet syndrome (TOS) was attained. Decompression of the brachial plexus by anterior approach has improved the painful symptoms and stabilized the motor status of our two patients. The diagnosis of plexus disease was reached in our two patients at the "true" neurogenic TOS stage (hand atrophy), evolving several years after a "disputed" neurogenic TOS (subjective complaints). These cases remind us to keep in mind the diagnosis of TOS in front of a cervicobrachialgia not or insufficiently explained by a cervical pathology.

  12. Biostereometric Analysis Of Therapeutic Results In The Treatment Of Chronic, Progressive, Decompensating Postural Back Strain

    NASA Astrophysics Data System (ADS)

    Johnson, David M.

    1980-07-01

    A two year pilot program for biostereometric analysis of treatment effectiveness in five patients with chronic decompensating back strain has been completed. The patients came from the investigators family practice of osteopathic medicine. They all manifested objective signs of ligamentous and muscular strain of their postural biomechanics due to the combined effects of prior injury to the musculoskeletal system, gravity strain and the passage of time. Two of the patients were treated with osteopathic manipulative treatment plus a pelvic leverage treatment device developed by Martin Jungman, M.D. Two patients received osteopathic treatment alone and the fifth individual switched from control to full program status in the middle of the study after the second stereophotography recording. Signs and symptoms of all patients' gravity strain syndrome changed during the program. Those patients who had the full combination of treatment modalities showed the most positive and significant postural changes as demonstrated by the biostereometric technique developed and performed by the Department of Biostereometrics, Texas Institute of Rehabilitation and Research, Baylor College of Medicine, Houston, Texas. Improvement was clearly demonstrated more quickly than with the prior radiographic measuring methods. X-ray and other studies have also been done on this group. All of the data has not been processed yet in this program. The test patients have improved posture, muscle mass and tone, more stamina and reduced pain.

  13. Hf-W Chronology of CR Chondrites

    NASA Astrophysics Data System (ADS)

    Budde, G.; Kruijer, T. S.; Kleine, T.

    2017-02-01

    Hf-W systematics of CR chondrites define an age of 3.7 Ma after CAIs for CR chondrule formation. CR metal and silicates have complementary nucleosynthetic W and Mo isotope anomalies due to the uneven distribution of a presolar s-process carrier.

  14. Safety and efficacy of simeprevir plus sofosbuvir with or without ribavirin in patients with decompensated genotype 1 hepatitis C cirrhosis.

    PubMed

    Modi, Apurva A; Nazario, Hector; Trotter, James F; Gautam, Manjushree; Weinstein, Jeffrey; Mantry, Parvez; Barnes, Maisha; Habib, Adil; McAfee, Jean; Teachenor, Olga; Tujague, Lauren; Gonzalez, Stevan

    2016-03-01

    Combination antiviral therapy involving sofosbuvir (SOF) and simeprevir (SIM) is a treatment option in patients with genotype 1 chronic hepatitis C; however, the safety of this regimen in patients with decompensated cirrhosis is not established. Data from a combined treatment cohort of 2 large hepatology referral centers were evaluated to assess for safety and efficacy of SIM plus SOF with or without ribavirin (RBV) in patients with Child B or C cirrhosis. All (n = 42) patients included in the analysis had Child B (n = 35) or C (n = 7) cirrhosis and received 400 mg daily of SOF plus 150 mg daily of SIM, with (n = 7) or without (n = 35) RBV, for 12 weeks. Of the 42 patients in this cohort, 31 (74%) were male, 22 (52%) had failed prior treatments, and 28 (67%) were genotype 1a. Prior decompensating events included encephalopathy (57%), fluid overload (88%), or variceal hemorrhage (24%). Median Model for End-Stage Liver Disease score was 12 (range, 6-25). Treatment was well tolerated overall with more than one-half (57%) reporting no adverse events. In those reporting adverse events, the most common were fatigue (n = 6), insomnia (n = 4), headache (n = 5), nausea (n = 4), and grade 1 rash (n = 1). One patient developed chemical pancreatitis that did not require treatment discontinuation. Three of 7 patients who received RBV developed anemia, with 2 requiring blood transfusions and 1 requiring a dose reduction. No episodes of decompensation requiring hospitalization or deaths occurred on treatment. Of 42 patients, 38 (90%) patients had negative viral load at end of treatment (EOT), and 31 of 42 patients (74%) achieved sustained virological response 12 weeks after EOT; 10 of 10 patients (100%) with HCV genotype 1b achieved sustained virological response for 12 weeks (SVR12). In conclusion, SOF plus SIM was very well tolerated in patients with advanced Child B/C decompensated cirrhosis. Overall, 74% of patients achieved SVR12

  15. SEMICONDUCTOR TECHNOLOGY: Wet etching characteristics of a HfSiON high-k dielectric in HF-based solutions

    NASA Astrophysics Data System (ADS)

    Yongliang, Li; Qiuxia, Xu

    2010-03-01

    The wet etching properties of a HfSiON high-k dielectric in HF-based solutions are investigated. HF-based solutions are the most promising wet chemistries for the removal of HfSiON, and etch selectivity of HF-based solutions can be improved by the addition of an acid and/or an alcohol to the HF solution. Due to densification during annealing, the etch rate of HfSiON annealed at 900 °C for 30 s is significantly reduced compared with as-deposited HfSiON in HF-based solutions. After the HfSiON film has been completely removed by HF-based solutions, it is not possible to etch the interfacial layer and the etched surface does not have a hydrophobic nature, since N diffuses to the interface layer or Si substrate formation of Si-N bonds that dissolves very slowly in HF-based solutions. Existing Si-N bonds at the interface between the new high-k dielectric deposit and the Si substrate may degrade the carrier mobility due to Coulomb scattering. In addition, we show that N2 plasma treatment before wet etching is not very effective in increasing the wet etch rate for a thin HfSiON film in our case.

  16. Pathophysiology of acute heart failure: a world to know.

    PubMed

    Sánchez-Marteles, M; Rubio Gracia, J; Giménez López, I

    2016-01-01

    Our understanding of the pathophysiological mechanisms of heart failure (HF) has changed considerably in recent years, progressing from a merely haemodynamic viewpoint to a concept of systemic and multifactorial involvement in which numerous mechanisms interact and concatenate. The effects of these mechanisms go beyond the heart itself, to other organs of vital importance such as the kidneys, liver and lungs. Despite this, the pathophysiology of acute HF still has aspects that elude our deeper understanding. Haemodynamic overload, venous congestion, neurohormonal systems, natriuretic peptides, inflammation, oxidative stress and its repercussion on cardiac and vascular remodelling are currently considered the main players in acute HF. Starting with the concept of acute HF, this review provides updates on the various mechanisms involved in this disease.

  17. [Diagnosis of acute heart failure and relevance of biomarkers in elderly patients].

    PubMed

    Ruiz Ortega, Raúl Antonio; Manzano, Luis; Montero-Pérez-Barquero, Manuel

    2014-03-01

    Diagnosis of acute heart failure (HF) is difficult in elderly patients with multiple comorbidities. Risk scales and classification criteria based exclusively on clinical manifestations, such as the Framingham scales, lack sufficient specificity. In addition to clinical manifestations, diagnosis should be based on two key factors: natriuretic peptides and echocardiographic study. When there is clinical suspicion of acute HF, a normal natriuretic peptide level will rule out this process. When a consistent clinical suspicion is present, an echocardiographic study should also be performed. Diagnosis of HF with preserved ejection fraction (HF/pEF) requires detection of an enlarged left atrium or the presence of parameters of diastolic dysfunction. Elevation of cardiac biomarkers seems to be due to myocardial injury and the compensatory mechanisms of the body against this injury (hormone and inflammatory response and repair mechanisms). Elevation of markers of cardiac damage (troponins and natriuretic peptides) have been shown to be useful both in the diagnosis of acute HF and in prediction of outcome. MMP-2 could be useful in the diagnosis of HF/pEF. In addition to biomarkers with diagnostic value, other biomarkers are helpful in prognosis in the acute phase of HF, such as biomarkers of renal failure (eGFR, cystatin and urea), inflammation (cytokines and CRP), and the cell regeneration marker, galectin-3. A promising idea that is under investigation is the use of panels of biomarkers, which could allow more accurate diagnosis and prognosis of acute HF.

  18. Heart Failure in Acute Ischemic Stroke

    PubMed Central

    Cuadrado-Godia, Elisa; Ois, Angel; Roquer, Jaume

    2010-01-01

    Heart failure (HF) is a complex clinical syndrome that can result from any structural or functional cardiac disorder that impairs the ability of the ventricle to fill with or eject blood. Due to the aging of the population it has become a growing public health problem in recent decades. Diagnosis of HF is clinical and there is no diagnostic test, although some basic complementary testing should be performed in all patients. Depending on the ejection fraction (EF), the syndrome is classified as HF with low EF or HF with normal EF (HFNEF). Although prognosis in HF is poor, HFNEF seems to be more benign. HF and ischemic stroke (IS) share vascular risk factors such as age, hypertension, diabetes mellitus, coronary artery disease and atrial fibrillation. Persons with HF have higher incidence of IS, varying from 1.7% to 10.4% per year across various cohort studies. The stroke rate increases with length of follow-up. Reduced EF, independent of severity, is associated with higher risk of stroke. Left ventricular mass and geometry are also related with stroke incidence, with concentric hypertrophy carrying the greatest risk. In HF with low EF, the stroke mechanism may be embolism, cerebral hypoperfusion or both, whereas in HFNEF the mechanism is more typically associated with chronic endothelial damage of the small vessels. Stroke in patients with HF is more severe and is associated with a higher rate of recurrence, dependency, and short term and long term mortality. Cardiac morbidity and mortality is also high in these patients. Acute stroke treatment in HF includes all the current therapeutic options to more carefully control blood pressure. For secondary prevention, optimal control of all vascular risk factors is essential. Antithrombotic therapy is mandatory, although the choice of a platelet inhibitor or anticoagulant drug depends on the cardiac disease. Trials are ongoing to evaluate anticoagulant therapy for prevention of embolism in patients with low EF who are at

  19. Peripartum cardiomyopathy: postpartum decompensation and use of non-invasive cardiac output monitoring.

    PubMed

    Lorello, G; Cubillos, J; McDonald, M; Balki, M

    2014-02-01

    The utility of a non-invasive cardiac output monitor (NICOM™) in guiding the peripartum management and identification of postpartum complications in a patient with severe peripartum cardiomyopathy is reported. A 31-year-old nulliparous woman at 35 weeks of gestation presented with a three-week history of worsening dyspnea and progressive functional deterioration. A transthoracic echocardiogram showed severe left ventricular systolic dysfunction with an ejection fraction <20%. Cardiac status was monitored using NICOM™ during labor and delivery. The baseline values were: cardiac output 5.3 L/min, total peripheral resistance 1549 dynes.sec/cm(5), stroke volume 42.1 mL and stroke volume variation 18%. She received early epidural analgesia during labor, titrated slowly with a loading dose of 0.0625% bupivacaine 10 mL and fentanyl 25 μg, followed by patient-controlled epidural analgesia (0.0625% bupivacaine with fentanyl 2 μg/mL, infusion at 10 mL/h, bolus dose 5 mL and lockout interval 10 min). After epidural drug administration, total peripheral resistance decreased, cardiac output increased, and satisfactory analgesia was obtained. She had an uneventful vaginal delivery with a forceps-assisted second stage after prophylactic administration of furosemide 20 mg. NICOM™ was discontinued after delivery. Fifteen hours post-delivery, the patient developed cardiogenic shock, which resolved after aggressive therapy with inotropes and furosemide. NICOM™ can be used to guide treatment during labor and delivery in patients with critical peripartum cardiomyopathy. We suggest that use of NICOM™ be extended into the postpartum period to detect signs of cardiac decompensation in such patients.

  20. Atrial Fibrillation in Decompensated Heart Failure: Associated Factors and In-Hospital Outcome

    PubMed Central

    Mendes, Fernanda de Souza Nogueira Sardinha; Atié, Jacob; Garcia, Marcelo Iorio; Gripp, Eliza de Almeida; de Sousa, Andréa Silvestre; Feijó, Luiz Augusto; Xavier, Sergio Salles

    2014-01-01

    Background Studies on atrial fibrillation (AF) in decompensated heart failure (DHF) are scarce in Brazil. Objectives To determine AF prevalence, its types and associated factors in patients hospitalized due to DHF; to assess their thromboembolic risk profile and anticoagulation rate; and to assess the impact of AF on in-hospital mortality and hospital length of stay. Methods Retrospective, observational, cross-sectional study of incident cases including 659 consecutive hospitalizations due to DHF, from 01/01/2006 to 12/31/2011. The thromboembolic risk was assessed by using CHADSVASc score. On univariate analysis, the chi-square, Student t and Mann Whitney tests were used. On multivariate analysis, logistic regression was used. Results The prevalence of AF was 40%, and the permanent type predominated (73.5%). On multivariate model, AF associated with advanced age (p < 0.0001), non-ischemic etiology (p = 0.02), right ventricular dysfunction (p = 0.03), lower systolic blood pressure (SBP) (p = 0.02), higher ejection fraction (EF) (p < 0.0001) and enlarged left atrium (LA) (p < 0.0001). The median CHADSVASc score was 4, and 90% of the cases had it ≥ 2. The anticoagulation rate was 52.8% on admission and 66.8% on discharge, being lower for higher scores. The group with AF had higher in-hospital mortality (11.0% versus 8.1%, p = 0.21) and longer hospital length of stay (20.5 ± 16 versus 16.3 ± 12, p = 0.001). Conclusions Atrial fibrillation is frequent in DHF, the most prevalent type being permanent AF. Atrial fibrillation is associated with more advanced age, non-ischemic etiology, right ventricular dysfunction, lower SBP, higher EF and enlarged LA. Despite the high thromboembolic risk profile, anticoagulation is underutilized. The presence of AF is associated with longer hospital length of stay and high mortality. PMID:25352505

  1. Influence of metabolic dysfunction on cardiac mechanics in decompensated hypertrophy and heart failure.

    PubMed

    Tewari, Shivendra G; Bugenhagen, Scott M; Vinnakota, Kalyan C; Rice, J Jeremy; Janssen, Paul M L; Beard, Daniel A

    2016-05-01

    Alterations in energetic state of the myocardium are associated with decompensated heart failure in humans and in animal models. However, the functional consequences of the observed changes in energetic state on mechanical function are not known. The primary aim of the study was to quantify mechanical/energetic coupling in the heart and to determine if energetic dysfunction can contribute to mechanical failure. A secondary aim was to apply a quantitative systems pharmacology analysis to investigate the effects of drugs that target cross-bridge cycling kinetics in heart failure-associated energetic dysfunction. Herein, a model of metabolite- and calcium-dependent myocardial mechanics was developed from calcium concentration and tension time courses in rat cardiac muscle obtained at different lengths and stimulation frequencies. The muscle dynamics model accounting for the effect of metabolites was integrated into a model of the cardiac ventricles to simulate pressure-volume dynamics in the heart. This cardiac model was integrated into a simple model of the circulation to investigate the effects of metabolic state on whole-body function. Simulations predict that reductions in metabolite pools observed in canine models of heart failure can cause systolic dysfunction, blood volume expansion, venous congestion, and ventricular dilation. Simulations also predict that myosin-activating drugs may partially counteract the effects of energetic state on cross-bridge mechanics in heart failure while increasing myocardial oxygen consumption. Our model analysis demonstrates how metabolic changes observed in heart failure are alone sufficient to cause systolic dysfunction and whole-body heart failure symptoms.

  2. Heterogeneous chemistry of HBr and HF

    SciTech Connect

    Hanson, D.R.; Ravishankara, A.R.

    1992-11-12

    The authors present information on heterogeneous chemistry of HF and HBr on glass and ice surfaces at a temperature of 200K. Their objective is to study whether heterogeneous reactions of these species could be important in the atmospheric chemistry occuring on NAT particles or cloud condensation nuclei, and be a contributor to ozone depletion. HF showed no significant uptake or reactions with ClONO{sub 2} or HOCl. HBr was found to adsorb on these surfaces, and did not exhibit saturation for even relative high concentrations. In addition it showed reactivity with ClONO{sub 2}, Cl{sub 2} and N{sub 2}O{sub 5} on ice surfaces.

  3. Materials performance in HF-alkylation units

    SciTech Connect

    Forsen, O.; Aromaa, J.; Somervuori, M.; Tavi, M.

    1995-11-01

    Materials selection in HF-alkylation units is mostly based on long time experience. The most widely used material in the Station units is standard carbon steel, because it is capable to form a thick protective FeF{sub 2} layer in concentrated or anhydrous hydrofluoric acid. The corrosion resistance decreases, when the acid is dilute (less than 64% HF) or the temperature is above 160F (70 C). The composition and metallurgical state are also suspected to affect the corrosion resistance of carbon steel. The effect of composition appears more complicated than believed, especially the A-106 specification on the total amount of Cr+Ni+Cu+Mo+V < 1% should be studied more closely from the corrosion point of view. Laboratory tests showed that the uniform corrosion rate may be 100 times higher in galvanic contact of two dissimilar steels. The effect of galvanic contacts can neither be excluded in the process equipment corrosion cases.

  4. Soft X-ray photoemission studies of Hf oxidation

    SciTech Connect

    Suzer, S.; Sayan, S.; Banaszak Holl, M.M.; Garfunkel, E.; Hussain, Z.; Hamdan, N.M.

    2002-02-01

    Soft X-Ray Photoemission Spectroscopy using surface sensitive Synchrotron Radiation has been applied to accurately determine the binding energy shifts and the valence band offset of the HfO2 grown on Hf metal. Charging of oxide films under x-rays (or other irradiation) is circumvented by controlled and sequential in-situ oxidation. Photoemission results show the presence of metallic Hf (from the substrate) with the 4f7/2 binding energy of 14.22 eV, fully oxidized Hf (from HfO2) with the 4f7/2 binding energy of 18.16 eV, and at least one clear suboxide peak. The position of the valence band of HfO2 with respect to the Hf(m) Fermi level is determined as 4.05 eV.

  5. Compact Reconfigurable HF-UHF Antennas

    DTIC Science & Technology

    2007-11-02

    7] P. J. Rainville, F. J. Harackewiez, Magnetic Tuning of a Microstrip Patch Antenna Fabricated on a Ferrite Film, IEEE Microwave and Guided Wave...Letters, 1992, Vol. 2 pp. 483-5. [8] R. K. Misra, S. S. Pattnaik, N. Das, Tuning of Microstrip Antenna on Ferrite Substrate, IEEE Transactions on...DATES COVERED Final , 01 June 1999 to 31 Dec., 2003 4. TITLE AND SUBTITLE Compact Reconfigurable HF-UHF antennas 5. FUNDING

  6. Improved HF Data Network Simulator. Volume 1

    DTIC Science & Technology

    1993-07-01

    flares - may cause HF blackouts, as can large terrestrial events such as volcanic eruptions and atomic explosions. The ionosphere exhibits a remarkable...of the earth interacts with the solar wind, causing rapid changes in the ionosphere that are made visible in part by the aurora borealis. The effects...backscatter - unpredictable changes in refraction from sporadic-E and F layers - excess path delays caused by non-great-circle modes propagating via

  7. Digitally Driven Antenna for HF Transmission

    DTIC Science & Technology

    2010-09-01

    ferrite -loaded loop as the receive antenna . The 1-MHz signal is clearly evident in the time-domain received signal on an oscilloscope, and also in the... MICROWAVE THEORY AND TECHNIQUES, VOL. 58, NO. 9, SEPTEMBER 2010 Digitally Driven Antenna for HF Transmission Steven D. Keller, Member, IEEE, W...MHz reference signal on the pulsewidth modulator as the transmitter and a highly inductive 470- H ferrite -loaded loop as the receive antenna . The 1-MHz

  8. Rationale and Design of the ATHENA-HF Trial: Aldosterone Targeted Neurohormonal Combined With Natriuresis Therapy in Heart Failure.

    PubMed

    Butler, Javed; Hernandez, Adrian F; Anstrom, Kevin J; Kalogeropoulos, Andreas; Redfield, Margaret M; Konstam, Marvin A; Tang, W H Wilson; Felker, G Michael; Shah, Monica R; Braunwald, Eugene

    2016-09-01

    Although therapy with mineralocorticoid receptor antagonists (MRAs) is recommended for patients with chronic heart failure (HF) with reduced ejection fraction and in post-infarction HF, it has not been studied well in acute HF (AHF) despite being commonly used in this setting. At high doses, MRA therapy in AHF may relieve congestion through its natriuretic properties and mitigate the effects of adverse neurohormonal activation associated with intravenous loop diuretics. The ATHENA-HF (Aldosterone Targeted Neurohormonal Combined with Natriuresis Therapy in Heart Failure) trial is a randomized, double-blind, placebo-controlled study of the safety and efficacy of 100 mg/day spironolactone versus placebo (or continued low-dose spironolactone use in participants who are already receiving spironolactone at baseline) in 360 patients hospitalized for AHF. Patients are randomized within 24 h of receiving the first dose of intravenous diuretics. The primary objective is to determine if high-dose spironolactone, compared with standard care, will lead to greater reductions in N-terminal pro-B-type natriuretic peptide levels from randomization to 96 h. The secondary endpoints include changes in the clinical congestion score, dyspnea relief, urine output, weight change, loop diuretic dose, and in-hospital worsening HF. Index hospital length of stay and 30-day clinical outcomes will be assessed. Safety endpoints include risk of hyperkalemia and renal function. Differences among patients with reduced versus preserved ejection fraction will be determined. (Study of High-dose Spironolactone vs. Placebo Therapy in Acute Heart Failure [ATHENA-HF]; NCT02235077).

  9. Room temperature formation of Hf-silicate layer by pulsed laser deposition with Hf-Si-O ternary reaction control

    NASA Astrophysics Data System (ADS)

    Hotta, Yasushi; Ueoka, Satoshi; Yoshida, Haruhiko; Arafune, Koji; Ogura, Atsushi; Satoh, Shin-ichi

    2016-10-01

    We investigated the room temperature growth of HfO2 layers on Si substrates by pulsed laser deposition under ultra-high vacuum conditions. The laser fluence (LF) during HfO2 layer growth was varied as a growth parameter in the experiments. X-ray photoemission spectroscopy (XPS) was used to observe the interface chemical states of the HfO2/Si samples produced by various LFs. The XPS results indicated that an interface Hf-silicate layer formed, even at room temperature, and that the thickness of this layer increased with increasing pulsed LF. Additionally, Hf-Si bonds were increasingly formed at the interface when the LF was more than 2 J/cm2. This bond formation process was related to decomposition of HfO2 to its atomic states of Hf and O by multiphoton photochemical processes for bandgap excitation of the HfO2 polycrystalline target. However, the Hf-Si bond content of the interface Hf-silicate layer is controllable under high LF conditions. The results presented here represent a practical contribution to the development of room temperature processing of Hf-compound based devices.

  10. Effectiveness of Remote Patient Monitoring After Discharge of Hospitalized Patients With Heart Failure: The Better Effectiveness After Transition–Heart Failure (BEAT-HF) Randomized Clinical Trial

    PubMed Central

    Ong, Michael K.; Romano, Patrick S.; Edgington, Sarah; Aronow, Harriet U.; Auerbach, Andrew D.; Black, Jeanne T.; De Marco, Teresa; Escarce, Jose J.; Evangelista, Lorraine S.; Hanna, Barbara; Ganiats, Theodore G.; Greenberg, Barry H.; Greenfield, Sheldon; Kaplan, Sherrie H.; Kimchi, Asher; Liu, Honghu; Lombardo, Dawn; Mangione, Carol M.; Sadeghi, Bahman; Sadeghi, Banafsheh; Sarrafzadeh, Majid; Tong, Kathleen; Fonarow, Gregg C.

    2016-01-01

    Importance It remains unclear whether telemonitoring approaches provide benefits for patients with heart failure (HF) after hospitalization. Objective To evaluate the effectiveness of a care transition intervention using remote patient monitoring in reducing 180-day all-cause readmissions among a broad population of older adults hospitalized with HF. Design, Setting, and Participants We randomized 1437 patients hospitalized for HF between October 12, 2011, and September 30, 2013, to the intervention arm (715 patients) or to the usual care arm (722 patients) of the Better Effectiveness After Transition–Heart Failure (BEAT-HF) study and observed them for 180 days. The dates of our study analysis were March 30, 2014, to October 1, 2015. The setting was 6 academic medical centers in California. Participants were hospitalized individuals 50 years or older who received active treatment for decompensated HF. Interventions The intervention combined health coaching telephone calls and telemonitoring. Telemonitoring used electronic equipment that collected daily information about blood pressure, heart rate, symptoms, and weight. Centralized registered nurses conducted telemonitoring reviews, protocolized actions, and telephone calls. Main outcomes and measures The primary outcome was readmission for any cause within 180 days after discharge. Secondary outcomes were all-cause readmission within 30 days, all-cause mortality at 30 and 180 days, and quality of life at 30 and 180 days. Results Among 1437 participants, the median age was 73 years. Overall, 46.2% (664 of 1437) were female, and 22.0% (316 of 1437) were African American. The intervention and usual care groups did not differ significantly in readmissions for any cause 180 days after discharge, which occurred in 50.8% (363 of 715) and 49.2% (355 of 722) of patients, respectively (adjusted hazard ratio, 1.03; 95% CI, 0.88-1.20; P = .74). In secondary analyses, there were no significant differences in 30-day

  11. Vasodilators in Acute Heart Failure: Review of the Latest Studies

    PubMed Central

    Levy, Phillip D.; Laribi, Said; Mebazaa, Alexandre

    2014-01-01

    Vasodilators play an important role in the management of acute heart failure, particularly when increased afterload is the precipitating cause of decompensation. The time-honored approach to afterload reduction has been largely focused on use of intravenous nitrovasodilators and, when properly dosed, this class of agents does provide substantial symptom relief for patients with acute hypertensive heart failure. Despite this, nitrovasodilators have never been shown to diminish mortality or provide any post-discharge outcome benefit leading to an on-going search for viable and more effective alternatives. While no new vasodilators have been approved for use in acute heart failure since nesiritide more than a decade ago, a number of novel agents have been developed, with some showing significant promise in recent clinical trials. In this review, we summarize the latest study data as it relates to vasodilator therapy and provide a glimpse into the not too distant future state of acute heart failure care. PMID:24855585

  12. Diagnostic and Prognostic Properties of Osteoprotegerin in Patients with Acute Dyspnoea: Observations from the Akershus Cardiac Examination (ACE) 2 Study

    PubMed Central

    Pervez, Mohammed Osman; Pedersen, Marit Holmefjord; Brynildsen, Jon; Høiseth, Arne Didrik; Hagve, Tor-Arne; Røsjø, Helge; Omland, Torbjørn

    2016-01-01

    Background Circulating osteoprotegerin (OPG) levels are increased in patients with chronic heart failure (HF). The diagnostic and prognostic merit of OPG measurement in patients admitted with acute dyspnoea is unknown. Objectives To evaluate the diagnostic and prognostic value of measuring OPG in patients admitted to hospital with acute dyspnoea. Methods OPG was analysed by ELISA in 308 patients admitted due to acute dyspnoea. Investigators blinded to OPG results adjudicated the diagnosis for the index hospitalization. Clinical outcomes were obtained from hospital records. Results In total, 139 patients (45%) were hospitalized with acute HF. OPG levels on hospital admission were higher in patients with acute HF vs. no acute HF, 7.8 (5.5–10.4) vs. 5.4 (3.8–7.2) pmol/L, p<0.001. The area under the receiver operator characteristic curve (ROC AUC) of OPG to discriminate between HF vs. non-HF was 0.695 [95% CI 0.636–0.754]. OPG did not provide incremental information to the ED physician’s prediction or N-terminal pro-B-type natriuretic peptide regarding the diagnosis of acute HF. OPG levels (log transformed) were associated with mortality in crude analysis (HR (95% CI) 1.87 (1.34 to 2.61), p<0.001), but this association was attenuated and no longer significant after including established cardiac biomarkers into the model. Conclusion In patients admitted to hospital with acute dyspnoea, OPG levels are higher in patients with acute HF than in those with dyspnoea from other causes. However, OPG does not provide incremental information beyond ED physician assessment for the diagnosis of acute HF or beyond clinical risk variables and established cardiac biomarkers concerning prognosis. PMID:27463973

  13. Magnetic properties of Hf177 and Hf180 in the strong-coupling deformed model

    NASA Astrophysics Data System (ADS)

    Muto, S.; Stone, N. J.; Bingham, C. R.; Stone, J. R.; Walker, P. M.; Audi, G.; Gaulard, C.; Köster, U.; Nikolov, J.; Nishimura, K.; Ohtsubo, T.; Podolyak, Z.; Risegari, L.; Simpson, G. S.; Veskovic, M.; Walters, W. B.

    2014-04-01

    This paper reports NMR measurements of the magnetic dipole moments of two high-K isomers, the 37/2-, 51.4 m, 2740 keV state in Hf177 and the 8-, 5.5 h, 1142 keV state in Hf180 by the method of on-line nuclear orientation. Also included are results on the angular distributions of γ transitions in the decay of the Hf177 isotope. These yield high precision E2/M1 multipole mixing ratios for transitions in bands built on the 23/2+, 1.1 s, isomer at 1315 keV and on the 9/2+, 0.663 ns, isomer at 321 keV. The new results are discussed in the light of the recently reported finding of systematic dependence of the behavior of the gR parameter upon the quasiproton and quasineutron make up of high-K isomeric states in this region.

  14. Cardiorenal biomarkers in acute heart failure

    PubMed Central

    Choudhary, Rajiv; Gopal, Dipika; Kipper, Ben A.; De La Parra Landa, Alejandro; Lee, Hermineh Aramin Elizabeth; Shah, Saloni; Maisel, Alan S.

    2012-01-01

    Managing patients with heart failure (HF) is a challenging task within itself, but the presence of associated worsening renal function can greatly increase mortality and morbidity. Early diagnosis and treatment is the key to prevent re-hospitalizations and reduce healthcare costs. Biomarkers have long been established as highly sensitive and specific tools in diagnosing and prognosticating patients with HF. Reflecting distinct pathophysiological events and ongoing cellular insult, biomarkers have been proven superior to conventional laboratory tests. Availability of better assays and rapid analysis has allowed the use of biomarkers as point-of-care tests in the emergency department and at the patient's bed-side. Acute HF patients often go on to develop worsening renal function, termed as acute cardiorenal syndrome. The growing breadth of studies has shown the implications of combining multiple biomarkers to better chart outcomes and produce desirable results in such patients. PMID:23097660

  15. LU-HF Age and Isotope Systematics of ALH84001

    NASA Technical Reports Server (NTRS)

    Righter, M.; Lapen, T. J.; Brandon, A. D.; Beard, B. L.; Shafer, J. T.; Peslier, A. H.

    2009-01-01

    Allan Hills (ALH) 84001 is an orthopyroxenite that is unique among the Martian meteorites in having the oldest inferred crystallization age (approx..4.5 to 4.0 Gyr) [e.g., 1-6 and references therein 7]. Its ancient origin makes this stone a critical constraint on early history of Mars, in particular the evolution of different planetary crust and mantle reservoirs. However, because there is significant variability in reported crystallization ages, determination of initial isotope compositions is imprecise making assessment of planetary reservoirs difficult. Here we report a new Lu-Hf mineral isochron age, initial Hf-176/Hf-177 isotope composition, and inferred Martian mantle source compositions for ALH84001 that place constraints on longlived source reservoirs for the enriched shergottite suite of Martian meteorites including Shergotty, Zagami, NWA4468, NWA856, RBT04262, LAR06319, and Los Angeles. Sm-Nd isotope analyses are under way for the same mineral aliquots analyzed for Lu-Hf. The Lu-Hf system was utilized because Lu and Hf are both lithophile and refractory and are not easily redistributed during short-lived thermal pulses associated with shock metamorphism. Moreover, chromite has relatively modest Hf concentrations with very low Lu/Hf ratios [9] yielding tight constraints on initial Hf-176/Hf-177 isotope compositions

  16. Decompensated liver cirrhosis and neural regulation of mesenteric vascular tone in rats: role of sympathetic, nitrergic and sensory innervations

    PubMed Central

    Sastre, Esther; Caracuel, Laura; Prieto, Isabel; Llévenes, Pablo; Aller, M. Ángeles; Arias, Jaime; Balfagón, Gloria; Blanco-Rivero, Javier

    2016-01-01

    We evaluated the possible alterations produced by liver cholestasis (LC), a model of decompensated liver cirrhosis in sympathetic, sensory and nitrergic nerve function in rat superior mesenteric arteries (SMA). The vasoconstrictor response to electrical field stimulation (EFS) was greater in LC animals. Alpha-adrenoceptor antagonist phentolamine and P2 purinoceptor antagonist suramin decreased this response in LC animals more than in control animals. Both non-specific nitric oxide synthase (NOS) L-NAME and calcitonin gene related peptide (CGRP) (8-37) increased the vasoconstrictor response to EFS more strongly in LC than in control segments. Vasomotor responses to noradrenaline (NA) or CGRP were greater in LC segments, while NO analogue DEA-NO induced a similar vasodilation in both experimental groups. The release of NA was not modified, while those of ATP, nitrite and CGRP were increased in segments from LC. Alpha 1 adrenoceptor, Rho kinase (ROCK) 1 and 2 and total myosin phosphatase (MYPT) expressions were not modified, while alpha 2B adrenoceptor, nNOS expression and nNOS and MYPT phosphorylation were increased by LC. Together, these alterations might counteract the increased splanchnic vasodilation observed in the last phases of decompensated liver cirrhosis. PMID:27484028

  17. High-aspect-ratio HfC nanobelts accompanied by HfC nanowires: Synthesis, characterization and field emission properties

    NASA Astrophysics Data System (ADS)

    Tian, Song; Zhang, Yulei; Ren, Jincui; Qiang, Xinfa; Zhang, Shouyang; Li, Hejun

    2017-04-01

    As a key refractory carbide, hafnium carbide (HfC) is commonly used as structural materials while the field emission (FE) application of HfC in the field of vacuum microelectronics is almost the only one for functional material purposes. Based on its outstanding physical and chemical characteristics, HfC is identified as a potential candidate with satisfactory mechanical properties and long-term and/or high-temperature FE stability for future applications in high-performance field emitters. However, the development of HfC in various FE applications is hindered because it is not facile to fabricate large-scale low-dimensional HfC field nanoemitters. Herein, High-aspect-ratio HfC nanobelts accompanied by HfC nanowires were synthesized on a large scale by a traditional and simple catalytic chemical vapor deposition (CVD) method. Classical vapor-liquid-solid (VLS) theory was employed to explain the growth of the HfC nanowires and nanobelts along axial direction. The thin HfO2 shell and thin C layer surrounding the nanostructures might give rise to the diameter fluctuation of HfC nanowires and the width increase of HfC nanobelts in lateral direction. Field emission results show that the high-aspect-ratio HfC nanobelts accompanied by the nanowires are promising field nanoemitters, which exhibit excellent field emission properties with a fairly low turn-on field of ∼1.5 V μm-1 and a low current fluctuation less than ∼10%. This suggests that HfC ceramics with high-aspect-ratio nanostructures are ideal cathode material for various field emission applications.

  18. Physics of the Geospace Response to Powerful HF Radio Waves

    DTIC Science & Technology

    2012-10-31

    Final 3. DATES COVERED (From - To) 10.01.2009-09.30.2012 4. TITLE AND SUBTITLE Physics of the Geospace Response to Powerful HF Radio Waves...facility in Alaska under the 2010-2012 AFOSR task `Physics of the Geospace Response to Powerful HF Radio Waves’. A first-principle model of a HF-created...Boulder, CO. 3. Mishin, E., Effects of high-power high frequency radio waves on geospace , Boston University Center for Space Physics, 18 March

  19. Acute-on-chronic liver failure: a review

    PubMed Central

    Zamora Nava, Luis Eduardo; Aguirre Valadez, Jonathan; Chávez-Tapia, Norberto C; Torre, Aldo

    2014-01-01

    There is no universally accepted definition of acute-on-chronic liver failure; however, it is recognized as an entity characterized by decompensation from an underlying chronic liver disease associated with organ failure that conveys high short-term mortality, with alcoholism and infection being the most frequent precipitating events. The pathophysiology involves inflammatory processes associated with a trigger factor in susceptible individuals (related to altered immunity in the cirrhotic population). This review addresses the different definitions developed by leading research groups, epidemiological and pathophysiological aspects, and the latest treatments for this entity. PMID:24790454

  20. Epitaxial Thin Films of Y doped HfO2

    NASA Astrophysics Data System (ADS)

    Serrao, Claudy; Khan, Asif; Ramamoorthy, Ramesh; Salahuddin, Sayeef

    Hafnium oxide (HfO2) is one of a few metal oxides that is thermodynamically stable on silicon and silicon oxide. There has been renewed interest in HfO2 due to the recent discovery of ferroelectricity and antiferroelectricity in doped HfO2. Typical ferroelectrics - such as strontium bismuth tantalate (SBT) and lead zirconium titanate (PZT) - contain elements that easily react with silicon and silicon oxide at elevated temperatures; therefore, such ferroelectrics are not suited for device applications. Meanwhile, ferroelectric HfO2 offers promise regarding integration with silicon. The stable phase of HfO2 at room temperature is monoclinic, but HfO2 can be stabilized in the tetragonal, orthorhombic or even cubic phase by suitable doping. We stabilized Y-doped HfO2 thin films using pulsed laser deposition. The strain state can be controlled using various perovskite substrates and controlled growth conditions. We report on Y-doped HfO2 domain structures from piezo-response force microscopy (PFM) and structural parameters via X-ray reciprocal space maps (RSM). We hope this work spurs further interest in strain-tuned ferroelectricity in doped HfO2.

  1. Mitigating Doppler shift effect in HF multitone data modem

    NASA Astrophysics Data System (ADS)

    Sonlu, Yasar

    1989-09-01

    Digital communications over High Frequency (HF) radio channels are getting important in recent years. Current HF requirements are for data transmission at rates 2.4 kbps or more to accommodate computer data links and digital secure voice. HF modems which were produced to meet these speeds are, serial modems and parallel modems. On the other hand, the HF sky-wave communication medium, the ionosphere, has some propagation problems such as multipath and Doppler shift. The effect of Doppler shift in a parallel modem which employs Differential Quadrature Phase Shift Keying (DQPSK) modulation is considered and a correction method to mitigate the Doppler Shift effect is introduced.

  2. HF-stabilization of plasma with sharp boundary

    NASA Astrophysics Data System (ADS)

    Kotelnikov, I. A.; Yakovchenko, S. G.

    The effect of HF natural oscillations of a plasma filament in a conducting cylindrical housing on the flute disturbance stability is investigated. Flute development leads to HF oscillation frequency (omega) variation connected with the energy W variation by the condition of constancy of the adiabatic invariant W/(omega) = const. The last is conserved owing to relative slow variations of flute disturbances. The adiabatic approximation used permits one to obtain simple criteria for flute instability stabilization by a HF field. HF oscillations of a plasma with a sharp boundary are considered.

  3. Ferroelectricity of nondoped thin HfO2 films in TiN/HfO2/TiN stacks

    NASA Astrophysics Data System (ADS)

    Nishimura, Tomonori; Xu, Lun; Shibayama, Shigehisa; Yajima, Takeaki; Migita, Shinji; Toriumi, Akira

    2016-08-01

    We report on the impact of TiN interfaces on the ferroelectricity of nondoped HfO2. Ferroelectric properties of nondoped HfO2 in TiN/HfO2/TiN stacks are shown in capacitance-voltage and polarization-voltage characteristics. The Curie temperature is also estimated to be around 500 °C. The ferroelectricity of nondoped HfO2 clearly appears by thinning HfO2 film down to ˜35 nm. We directly revealed in thermal treatments that the ferroelectric HfO2 film on TiN was maintained by covering the top surface of HfO2 with TiN, while it was followed by a phase transition to the paraelectric phase in the case of the open surface of HfO2. Thus, it is concluded that the ferroelectricity in nondoped HfO2 in this study was mainly driven by both of top and bottom TiN interfaces.

  4. Importance of the Decompensative Correction of the Gravity Field for Study of the Upper Crust: Application to the Arabian Plate and Surroundings

    NASA Astrophysics Data System (ADS)

    Kaban, Mikhail K.; El Khrepy, Sami; Al-Arifi, Nassir

    2017-01-01

    The isostatic correction represents one of the most useful "geological" reduction methods of the gravity field. With this correction it is possible to remove a significant part of the effect of deep density heterogeneity, which dominates in the Bouguer gravity anomalies. However, even this reduction does not show the full gravity effect of unknown anomalies in the upper crust since their impact is substantially reduced by the isostatic compensation. We analyze a so-called decompensative correction of the isostatic anomalies, which provides a possibility to separate these effects. It was demonstrated that this correction is very significant at the mid-range wavelengths and may exceed 100 m/s2 (mGal), therefore ignoring this effect would lead to wrong conclusions about the upper crust structure. At the same time, the decompensative correction is very sensitive to the compensation depth and effective elastic thickness of the lithosphere. Therefore, these parameters should be properly determined based on other studies. Based on this technique, we estimate the decompensative correction for the Arabian plate and surrounding regions. The amplitude of the decompensative anomalies reaches ±250 m/s2 10-5 (mGal), evidencing for both, large density anomalies of the upper crust (including sediments) and strong isostatic disturbances of the lithosphere. These results improve the knowledge about the crustal structure in the Middle East.

  5. Hf isotope and concentration systematics of the Mariana arc

    NASA Astrophysics Data System (ADS)

    Tollstrup, D. L.; Gill, J. B.

    2004-12-01

    Negative Hf concentration anomalies are common but little-discussed geochemical features of island arcs. Because both light rare earth elements (LREE) and Hf may be mobile even in `fluid-dominated' island arcs, it is important to relate their isotopic and elemental ratios to models of slab-mantle mixing. We report new Hf isotope and trace element data for K-rich submarine basalts from the Kasuga seamounts located 10-20 km behind the volcanic front of the southern Northern Seamount Province (NSP) of the Mariana arc. These data, when combined with published data for other Mariana samples, span the full range from low-K tholeiites to high-K shoshonites. Rear-arc Kasuga seamounts seamounts of the NSP have lower 143Nd/144Nd and 176Hf/177Hf ratios than arc-front volcanoes of the Mariana Central Island Province (CIP). Within the CIP, Hf concentration anomalies correlate positively with 176Hf/177Hf ratios. Radiogenic Hf and little or no concentration anomalies characterize samples from fluid-dominated volcanoes (Guguan and Maug), whereas samples from sediment-melt dominated volcanoes (Anatahan and Sarigan) have less radiogenic Hf and larger concentration anomalies. Samples from the Kasuga and Hiyoshi seamounts have even larger negative concentration anomalies and less radiogenic Hf, although the two are not always correlated. These data are consistent with mixing between a depleted mantle and a partial melt of subducted sediment that is saturated with trace accessory phases including zircon, rutile, and monazite. A more volcaniclastic source is needed for the NSP than the CIP. Implications of these findings are three-fold. Partial melts of subducting sediment affect the HFSE and REE budgets of even fluid-dominated island arcs. Slab temperatures must be high enough for a peraluminous melt to be present, even where old, cold slabs are subducting. Refractory accessory phases have the potential to become exotic "nuggets" in the convecting mantle, potentially controlling the

  6. Telbivudine versus lamivudine and entecavir for treatment-naïve decompensated hepatitis B virus-related cirrhosis.

    PubMed

    Yue-Meng, Wan; Li, Yu-Hua; Wu, Hua-Mei; Yang, Jing; Xu, Ying; Yang, Li-Hong; Yang, Jin-Hui

    2016-04-19

    The long-term effects of telbivudine (TBV) on decompensated hepatitis B virus (HBV)-related cirrhosis were still not established. This study aimed to investigate the efficacy and safety of TBV in such cohort of patients as compared to lamivudine (LAM) and entecavir (ETV). We retrospectively evaluated 130 treatment-naïve patients with HBV-related decompensated cirrhosis who started treatment with TBV (n = 31), LAM (n = 45) or ETV (n = 54). After 24 months of treatment, cumulative virological response (VR) rates (HBV DNA <500 copies/mL) were 83.7, 65.3 and 89.1 % in TBV, LAM and ETV groups, respectively (p = 0.009). Reduction in HBV DNA levels in TBV was -3.66 ± 0.56, significantly higher than LAM (-3.34 ± 0.59; p < 0.05) and lower than ETV group (-3.98 ± 0.52; p < 0.05). The rates of HBeAg loss or seroconversion and normalization of alanine aminotransferase (ALT) were similar among the groups. Child-Turcotte-Pugh (CTP) score and model for end-stage liver disease score in TBV were significantly improved compared to at baseline without difference among the groups. TBV resulted in similar cumulative rates of survival and incidence of hepatocellular carcinoma (HCC) to LAM and ETV. Frequencies of complications from cirrhosis, including variceal bleeding, hepatic encephalopathy and spontaneous bacterial peritonitis, were comparable among the groups. Four patients (16.7 %) in TBV displayed virological breakthrough, lower than LAM and higher than ETV (p = 0.004). Cox regression analysis showed that baseline HBV DNA (hazard ratio 0.743; 95 % confidence interval 0.582-949, p = 0.017) was an independent predictor for VR at 24 months. Long-term therapy with TBV was effective and safe in HBV-related decompensated cirrhosis.

  7. In vitro cytotoxicity and hemocompatibility studies of Ti-Nb, Ti-Nb-Zr and Ti-Nb-Hf biomedical shape memory alloys.

    PubMed

    Wang, B L; Li, L; Zheng, Y F

    2010-08-01

    The in vitro cytotoxicity and hemocompatibility of the Ti-Nb, Ti-Nb-Zr and Ti-Nb-Hf biomedical shape memory alloys (SMAs) were investigated by cell culture (L-929 fibroblast cell), hemolytic test and platelet adhesion test, with CP Ti as a reference material. The cytotoxicity test indicates that all the Ti-Nb, Ti-Nb-Zr and Ti-Nb-Hf SMAs show over 94% cell viability for different incubation times (2, 4 and 7 days) in comparison with a negative control and CP Ti. The cell morphology observation shows good polygon-like adherent growth and proliferation of L-929 in the extracts of all the test samples and CP Ti. These results suggest excellent cytocompatibility for the Ti-Nb, Ti-Nb-Zr and Ti-Nb-Hf SMAs. The hemolytic test reveals that the hemolysis ratios of the Ti-Nb, Ti-Nb-Zr and Ti-Nb-Hf alloys are far less than 5%, so they cannot give rise to acute hemolysis. The platelet morphology observation shows almost the same adhered platelet morphology and activation ratio for the test samples in comparison with CP Ti, except the Ti-22Nb-6Hf alloy, which shows a lower activation ratio of platelets, indicating excellent blood compatibility. Therefore, it is proposed that the Ti-Nb, Ti-Nb-Zr and Ti-Nb-Hf SMAs will be candidates to replace Ti-Ni for biomedical applications.

  8. Fractionation of Zr and Hf in surface processes

    SciTech Connect

    Chyi, L.L.; Garg, A.N.

    1985-01-01

    Zircons from a pegmatite near Tuxedo, North Carolina were crushed and treated with different reagents under different conditions. The treated and untreated samples were determined for Zr and Hf with radiochemical neutron activation analysis. Zircons treated with 50% sulfuric acid were having lowered Zr content and Zr/Hf ratio. The conclusions are that a portion of Zr and Hf in zircons is sensitive to leaching, and Zr appears to be selectively leached over Hf. The conclusions of this work support the observations of small dissolutions of Zr in both acidic podzolic soils and in alkaline laterites, of lower Zr content in soils on glacial drift, and of lower Zr/Hf ratios in loess deposits from various parts of the world. The fractionation of Zr and Hf in surface processes appears to be due to selective leaching. Weakening of Zr-O over Hf-O bonds in zircon by fission projectiles is postulated to be the viable process. The observed fractionation from leaching experiments suggest that areas receiving leachates such as swamps, lakes, and oceans should have high to very high Zr/Hf ratios preserved in rocks. High ratios are found in the Springfield (No. 9) Coal, the Green River Shale, and various limestones. High ratio is also found in orchard leaves, which grow by absorbing leachate from soil.

  9. Crystal structure of Si-doped HfO2

    NASA Astrophysics Data System (ADS)

    Zhao, Lili; Nelson, Matthew; Aldridge, Henry; Iamsasri, Thanakorn; Fancher, Chris M.; Forrester, Jennifer S.; Nishida, Toshikazu; Moghaddam, Saeed; Jones, Jacob L.

    2014-01-01

    Si-doped HfO2 was prepared by solid state synthesis of the starting oxides. Using Rietveld refinement of high resolution X-ray diffraction patterns, a substitutional limit of Si in HfO2 was determined as less than 9 at. %. A second phase was identified as Cristobalite (SiO2) rather than HfSiO4, the latter of which would be expected from existing SiO2-HfO2 phase diagrams. Crystallographic refinement with increased Si-dopant concentration in monoclinic HfO2 shows that c/b increases, while β decreases. The spontaneous strain, which characterizes the ferroelastic distortion of the unit cell, was calculated and shown to decrease with increasing Si substitution.

  10. Calculation of Electron Affinity and Partial Cross Sections of Hf^-

    NASA Astrophysics Data System (ADS)

    Pan, Lin; Beck, Donald

    2008-05-01

    We have calculated for the first time the electron affinity (EA) of Hf^-, using the relativistic configuration interaction method. Our calculations show Hf^- has only one bound state 5d^26s^26p J=5/2, which is a 6p attachment to the ground state of Hf I. By combining our valence stage result with the separate estimate for the modest core-valence contribution, the EA of Hf^- is about 0.114 eV. So far there have been only two experimental results [1,2] for the EA of Hf^-, but both gave only the limits. Our result falls within both of the limits. We also calculate the partial cross sections for photodetachment to the lower lying neutral thresholds. [1] M-J. Nadeau et al, Nucl. Instr. and Meth. B 123, 521 (1997) [2] Vernon T. Davis et al, Nucl. Instr. and Meth. B 241, 118 (2005)

  11. Hf propagation through actively modified ionospheres

    SciTech Connect

    Argo, P.E.; Fitzgerald, T.J.; Wolcott, J.H.; Simons, D.J. ); Warshaw, S.; Carlson, R. )

    1990-01-01

    We have developed a computer modeling capability to predict the effect of localized electron density perturbations created by chemical releases or high-power radio frequency heating upon oblique, one-hop hf propagation paths. We have included 3-d deterministic descriptions of the depleted or enhanced ionization, including formation, evolution, and drift. We have developed a homing ray trace code to calculate the path of energy propagation through the modified ionosphere in order to predict multipath effects. We also consider the effect of random index of refraction variations using a formalism to calculate the mutual coherence functions for spatial and frequency separations based upon a path integral solution of the parabolic wave equation for a single refracted path through an ionosphere which contains random electron density fluctuations. 5 refs., 8 figs.

  12. Time synchronisation of an HF radio modem

    NASA Astrophysics Data System (ADS)

    Clark, A. P.; McVerry, F.

    1982-12-01

    The present investigation is concerned with a technique for time synchronization which is of potential value in any application of time synchronization where an estimate of the sampled impulse response of a time-varying linear baseband channel is required but the particular phase of the sampling instants is hot important. The technique appears to be both simple and effective and to be capable of development into a useful practical system. Attention is given to the results of computer simulation tests which show the performance of the technique in a 9600 bit/s quadrature-amplitude-modulated (QAM) data-transmission system operating over a model of an HF radio link. The data-transmission system is considered along with the control of the sampling instants, and details concerning the computer simulation tests.

  13. Orthodontic decompensation and correction of skeletal Class III malocclusion with gradual dentoalveolar remodeling in a growing patient.

    PubMed

    Cai, Bin; Zhao, Xiao-Guang; Xiang, Lu-Sai

    2014-03-01

    An 8-year-old girl with a skeletal Class III malocclusion was treated in 2 phases. Maxillary expansion and protraction were carried out as the early intervention. However, her maxillary hypoplasia and mandibular hyperplasia deteriorated with age. The phase 2 comprehensive treatment began with proper mechanics when she was 12 years old with growth potential. In the maxillary arch, an auxiliary rectangular wire was used with a round main wire and an opening spring to create space for the impacted teeth and to bodily move the anterior teeth forward. Decompensation of mandibular incisors and correction of the Class III malocclusion were achieved by short Class III elastics with light forces and a gentle interaction between the rectangular wires and the lingual root-torque slots. The phase 2 active treatment period was 4 years 8 months. The 2-year follow-up indicated that our treatment results were quite stable.

  14. Tissue Doppler Imaging in the Estimation of Intracardiac Filling Pressure in Decompensated Patients with Advanced Systolic Heart Failure

    PubMed Central

    Mullens, Wilfried; Borowski, Allen G; Curtin, Ronan J; Thomas, James D; Tang, W. H. Wilson

    2011-01-01

    Background Early transmitral velocity / tissue Doppler mitral annular early diastolic velocity (E/Ea) has been correlated with pulmonary capillary wedge pressure (PCWP) in a wide variety of cardiac conditions. The objective of this study was to determine the reliability of mitral E/Ea for predicting PCWP in patients admitted for advanced decompensated heart failure (ADHF). Methods and Results Prospective consecutive patients with ADHF (ejection fraction [EF] ≤30%, NYHA class III-IV symptoms) underwent simultaneous echocardiographic and hemodynamic evaluation on admission and after 48 hours of intensive medical therapy. A total of 106 patients were included (mean age 57 ±12 years, EF 24 ±8%, PCWP 21 ±7 mmHg, mitral E/Ea 20 ±12). There was a lack of correlation between mitral E/Ea and PCWP, particularly in those with larger LV volumes, more impaired cardiac indices, and the presence of cardiac resynchronization therapy. Overall, mitral E/Ea was similar among patients with PCWP > and ≤ 18 mmHg, and sensitivity and specificity for mitral E/Ea > 15 to identify a PCWP > 18 mmHg was 66% and 50%, respectively. Contrary to prior reports, we did not observe any direct association between changes in PCWP and changes in mitral E/Ea. Conclusion In decompensated patients with advanced systolic heart failure, tissue Doppler derived mitral E/Ea may not be as reliable in predicting intracardiac filling pressures, particularly in those with larger LV volumes, more impaired cardiac indices, and the presence of cardiac resynchronization therapy. PMID:19075104

  15. Efficacy and safety of entecavir and/or tenofovir in hepatitis B compensated and decompensated cirrhotic patients in clinical practice.

    PubMed

    Miquel, Mireia; Núñez, Óscar; Trapero-Marugán, María; Díaz-Sánchez, Antonio; Jiménez, Miguel; Arenas, Juan; Canós, Antonio Palau

    2013-01-01

    This study aimed to evaluate the efficacy and safety of entecavir and/or tenofovir in compensated (CC) or decompensated (DC) hepatitis B cirrhotic patients in real-life clinical practice. Of the 48 patients, included between April 2007 and March 2010, 12 were DC. The mean age was 55 ± 12.2 years, 85.4% were Caucasians and 8 patients were HBeAg positive. Mean viral load was 5.2 ± 1.9 log(10) UI/mL. HBV-DNA undetectability at 3, 6, 12 and 24 months were 53.3%, 78.3%, 83.7% and 97.1%, respectively, similar in CC and DC. At 6 and 12 months, ≥ 80% of CC achieved ALT normalization, while only 42.9% and 71.4% in DC. After a median follow-up of 27.1 (0.7-45.3) months, 43 patients were Child Pugh Turcotte (CPT) class A (n = 39 at entry). In DC, progressive improvement in the MELD scores was observed: 12.73 (SD 4.5), 10.4 (SD 3.6) and 8.2 (SD 2.6), at baseline, 12 and 24 months, respectively. During follow-up, 7 patients died, 4 received liver transplantation and 5 developed hepatocellular carcinoma. In three out of four DC who died due to hepatic causes, these events occurred between the first 0.7 and 6.7 months, and all were CPT class C. Cumulative survival in CC vs. DC at 12 and 24 months were 94.4% vs. 66.7%, and 88.2% vs. 57.1%, respectively (log rank p = 0.03). No severe adverse events associated with entecavir or tenofovir were reported. In conclusion, in compensated and decompensated cirrhotic patients, entecavir and tenofovir were effective and well tolerated.

  16. [Value of N-terminal pro brain natriuretic peptide in predicting acute kidney injury in patients with acute decompensated chronic heart failure].

    PubMed

    Menzorov, M V; Shutov, A M; Midlenko, V I; Larionova, N V; Morozova, I V; Akulova, O V

    2017-01-01

    Цель исследования. Изучить прогностическое значение N-концевого предшественника мозгового натрийуретического пептида (NT-proBNP) сыворотки крови в развитии острого повреждения почек (ОПП) у больных с острой декомпенсацией хронической сердечной недостаточности (ОДХСН). Материалы и методы. Обследовали 83 больных с ОДХСН — 55 (66%) мужчин и 28 (34%) женщин, средний возраст составил 65±11 лет. ОПП диагностировали и классифицировали согласно Рекомендациям KDIGO (2012). Чтобы исключить индуцированное контрастным веществом ОПП, в исследование включили только пациентов, которым во время госпитализации и за 7 дней до нее не вводились рентгеноконтрастные препараты. У всех пациентов при поступлении в стационар определяли концентрацию NT-proBNP в сыворотке крови иммуноферментным методом. Результаты. ОПП диагностировано у 18 (22%) больных, причем у 13 (16%) I стадию, 4 (5%) II стадию, 1 (1%) III стадию ОПП. Концентрация NT-proBNP в сыворотке крови была достоверно выше у больных с ОПП по сравнению с остальными пациентами — 1512,1 (981,0; 2246,2) и 861,8 (499,0; 1383,6) пг/мл (p=0,008). Установлено, что концентрация NT-proBNP более 942 пг/мл ассоциирована со значительным ростом риска развития ОПП (относительный риск — ОР 4,3 при 95% доверительном интервале — ДИ от 1,27 до 14,90; p=0,02). По данным RОС-анализа, уровень NT-proBNP >942 пг/мл позволяет прогнозировать ОПП с чувствительностью 78 (52; 94) % и специфичностью 55 (44; 69) % (AUC=0,70; р=0,006). В стационаре умерли 4 (5%) больных. У всех умерших уровень NT-proBNP превышал 942 пг/мл. У 2 из 4 умерших больных имелось ОПП. Заключение. Высокий уровень NT-proBNP во время госпитализации больного ОДХСН может служить биомаркером высокого риска развития ОПП и высокой летальности.

  17. Ferroelectricity-modulated resistive switching in Pt/Si:HfO2/HfO2-x /Pt memory

    NASA Astrophysics Data System (ADS)

    Ran, Jiang; Xianghao, Du; Zuyin, Han

    2016-08-01

    It is investigated for the effect of a ferroelectric Si:HfO2 thin film on the resistive switching in a stacked Pt/Si:HfO2/highly-oxygen-deficient HfO2-x /Pt structure. Improved resistance performance was observed. It was concluded that the observed resistive switching behavior was related to the modulation of the width and height of a depletion barrier in the HfO2-x layer, which was caused by the Si:HfO2 ferroelectric polarization field effect. Reliable switching reproducibility and long data retention were observed in these memory cells, suggesting their great potential in non-volatile memories applications with full compatibility and simplicity. Project supported by the National Natural Science Foundation of China (No. 11374182), the Natural Science Foundation of Shandong Province (No. ZR2012FQ012), and the Jinan Independent Innovation Projects of Universities (No. 201303019).

  18. Hf-Nd isotope and trace element constraints on subduction inputs at island arcs: limitations of Hf anomalies as sediment input indicators

    NASA Astrophysics Data System (ADS)

    Handley, H. K.; Turner, S.; MacPherson, C.; Davidson, J. P.; Gertisser, R.

    2010-12-01

    New Nd-Hf isotope and trace element data for Javanese volcanoes are combined with recently published data to place constraints on subduction inputs at the Sunda arc in Indonesia and assess the value of Hf anomalies (expressed as Hf/Hf* and Sm/Hf ratios) as tracers of such inputs. Hf anomaly does not correlate with Hf isotope ratio in Javanese lavas however, Hf/Hf* and Sm/Hf ratios do correlate with SiO2. Contrary to previous work, we show that Hf anomaly variation may be controlled by fractionation of clinopyroxene and/or amphibole during magmatic differentiation and does not represent the magnitude or type of subduction input in some arcs. Correlation of Sm/Hf with indices of differentiation for other arcs (e.g. Vanuatu, New Britain, Mariana) suggests that differentiation control on Sm/Hf ratios of volcanic rocks may be a relatively common phenomenon. This study corroborates the use of Nd-Hf isotope co-variations in arc volcanic rocks to ascertain subduction input characteristics. The trajectories of regional volcano groups (East, Central and West Java) in Nd-Hf isotope space reveal heterogeneity in the subducted sediment input along Java, which reflects present-day spatial variations in sediment compositions on the down-going plate in the Java Trench.

  19. Large Nd-Hf isotopic decoupling in Himalayan River Sediments

    NASA Astrophysics Data System (ADS)

    Garcon, M.; Chauvel, C.; France-Lanord, C.

    2011-12-01

    Nd isotopic compositions of river sediments are widely used to trace sediment provenance in the Himalayan mountain range. In contrast, Hf isotopic compositions are not used even though they are excellent proxies to record the history of continental areas (Hawkesworth and Kemp, Chem. Geol. 226, 2006). Here, we focus on the Hf isotopic message carried by Himalayan river sediments and combine it to the more classical Nd isotopes to better understand the behavior of the two systems during erosion. We report Nd-Hf isotopic compositions of bedloads and suspended loads sampled at different depths in the Narayani River in Nepal (upstream of the Ganga floodplain), in the Ganga River in Bangladesh (downstream of the Ganga floodplain) and in the Yamuna River, a major tributary of the Ganga in India. Nd-Hf isotopic compositions of bedloads span a small range of values (-18< ɛNd <-16 and -30< ɛHf <-23) and lie next to the terrestrial array in a ɛHf vs. ɛNd diagram. Nd isotopic compositions are similar to those of the main Himalayan sources. By contrast, suspended loads have much more variable ratios (-19< ɛNd <-10 and -25< ɛHf <-7) and plot well above the terrestrial array in a ɛHf vs. ɛNd diagram. Like oceanic sediments, they are characterized by high ɛHf compared to their ɛNd. We explain this Nd-Hf decoupling by mineralogical sorting, a process that enriches bottom sediments in coarse and dense minerals, such as unradiogenic zircons, while the surface sediments are enriched in fine material with radiogenic Hf signatures. Bedloads and suspended loads, collected at the same sampling site at different depths in the Narayani and Ganga Rivers, share similar ɛNd. However, differences of about 5 ɛNd and 15 ɛHf units are observed between bedload and surface samples in the Yamuna River. In this river, both Nd and Hf isotopic ratios decrease from surface to bottom. We believe that part of the Hf isotopic variability is due to mineralogical sorting but the rest of it

  20. Power-Stepped HF Cross Modulation Experiments at HAARP

    NASA Astrophysics Data System (ADS)

    Greene, S.; Moore, R. C.; Langston, J. S.

    2013-12-01

    High frequency (HF) cross modulation experiments are a well established means for probing the HF-modified characteristics of the D-region ionosphere. In this paper, we apply experimental observations of HF cross-modulation to the related problem of ELF/VLF wave generation. HF cross-modulation measurements are used to evaluate the efficiency of ionospheric conductivity modulation during power-stepped modulated HF heating experiments. The results are compared to previously published dependencies of ELF/VLF wave amplitude on HF peak power. The experiments were performed during the March 2013 campaign at the High Frequency Active Auroral Research Program (HAARP) Observatory. HAARP was operated in a dual-beam transmission format: the first beam heated the ionosphere using sinusoidal amplitude modulation while the second beam broadcast a series of low-power probe pulses. The peak power of the modulating beam was incremented in 1-dB steps. We compare the minimum and maximum cross-modulation effect and the amplitude of the resulting cross-modulation waveform to the expected power-law dependence of ELF/VLF wave amplitude on HF power.

  1. Critical Questions about PARADIGM-HF and the Future.

    PubMed

    Chen, Chen-Huan

    2016-07-01

    Cardiovascular (CV) diseases in general and heart failure (HF) in particular are major contributors to death and morbidity and are also recognized as important drivers of health care expenditure. The PARADIGM-HF trial was a pivotal trial designed to compare the long-term effects of LCZ696 with enalapril in patients with symptomatic HF with reduced ejection fraction (HFrEF). This review article presents an in-depth view of the PARADIGM-HF trial and the implications of the results in the management of patients with HF and is based on peer reviewed manuscripts, editorials, perspectives and opinions written about the PARADIGM-HF trial. The article presents the key safety and efficacy results of the trial with specific emphasis on the clinical implications of these findings. The review highlights the highly statistically significant, 20% reduction in the primary composite endpoint of cardiovascular death or HF hospitalization, and a 16% reduction in the risk of death from any cause. It also provides an overview of the design, clinical findings, limitations and special areas of clinical interest. The review discusses the future of LCZ696 and additional trials that seek to answer questions in other sub-populations of patients with HF. The article reiterates what has been concluded by many experts in the field of HF- the introduction of LCZ696 into routine clinical care, while dependent on the regulatory approvals in various countries as well as acceptance by physicians, payers and patients, will change the treatment landscape for patients with HFrEF.

  2. Critical Questions about PARADIGM-HF and the Future

    PubMed Central

    Chen, Chen-Huan

    2016-01-01

    Cardiovascular (CV) diseases in general and heart failure (HF) in particular are major contributors to death and morbidity and are also recognized as important drivers of health care expenditure. The PARADIGM-HF trial was a pivotal trial designed to compare the long-term effects of LCZ696 with enalapril in patients with symptomatic HF with reduced ejection fraction (HFrEF). This review article presents an in-depth view of the PARADIGM-HF trial and the implications of the results in the management of patients with HF and is based on peer reviewed manuscripts, editorials, perspectives and opinions written about the PARADIGM-HF trial. The article presents the key safety and efficacy results of the trial with specific emphasis on the clinical implications of these findings. The review highlights the highly statistically significant, 20% reduction in the primary composite endpoint of cardiovascular death or HF hospitalization, and a 16% reduction in the risk of death from any cause. It also provides an overview of the design, clinical findings, limitations and special areas of clinical interest. The review discusses the future of LCZ696 and additional trials that seek to answer questions in other sub-populations of patients with HF. The article reiterates what has been concluded by many experts in the field of HF- the introduction of LCZ696 into routine clinical care, while dependent on the regulatory approvals in various countries as well as acceptance by physicians, payers and patients, will change the treatment landscape for patients with HFrEF. PMID:27471351

  3. Transionospheric HF Propagation Experiments at Auroral Latitudes

    NASA Astrophysics Data System (ADS)

    James, H. G.; Benson, R. F.

    2004-05-01

    High-frequency (HF) propagation experiments are planned as part of the Enhanced Polar Outflow Probe (ePOP) satellite mission to be launched for the Canadian Space Agency in 2007. Ground transmitters such as the CADI ionosondes and the SuperDARN radars will be operated collaboratively to emit waves for detection by the Radio Receiver Instrument of ePOP during passes in the vicinity. The scientific goals include improved understanding of F-region morphology and dynamics, wave scattering and microphysical plasma processes. Partly as preparation for ePOP, transionospheric HF propagation data recorded by the receivers of the ISIS-I and ISIS-II spacecraft are being analyzed. The measurements were made in spring-summer 1978. A ground transmitter was built in Ottawa especially for the project. Some of the ISIS data were obtained in digital form from http://nssdc.gsfc.nasa.gov/space/isis/isis-status.html. These digital data are being surveyed in an attempt to establish repeatable propagation characteristics. From these characteristics, the goal is to understand the processes experienced by waves passing through the ionosphere. Several tens of ISIS-II passes recorded at a fixed frequency of 9.303 MHz have been examined. Swept-frequency ionograms interleaved with these fixed-frequency measurements allow two-dimensional electron density distributions to be modeled in altitude and latitude. Computer code has been developed for three-dimensional ray tracing. The computed latitudinal extent of the zone irradiated at the ISIS-II altitude is approximately as observed. Within this "iris" of accessibility, the peak intensity of waves recorded at the spacecraft is within about 10 dB of what is computed with a link calculation. This calculation is based on a model for the 1-kW transmitter, a radiant-transfer calculation that follows the focusing/defocusing of rays using a three-ray pencil between ground and the satellite, and the orientation of the sounder receiving dipole. Poleward

  4. Control of the static and high-frequency magnetic properties of perpendicular anisotropic Co–HfN granular films through insertion of HfN interlayers

    NASA Astrophysics Data System (ADS)

    Cao, Yang; Zhang, Yiwen; Ohnuma, Shigehiro; Kobayashi, Nobukiyo; Masumoto, Hiroshi

    2017-04-01

    We propose a multilayer granular structure wherein Hf–nitride (HfN) interlayers are inserted into Co–HfN granular films with perpendicular magnetic anisotropy (PMA) to control their static and high-frequency magnetic properties. The transition between soft ferromagnetic properties and PMA was achieved by varying the thickness of Co–HfN layers (2–30 nm) and HfN interlayers (1–4 nm). The resonance frequency of the Co–HfN (24 nm)/HfN films decreased from 2 to 0.9 GHz with increasing HfN interlayer thickness, owning to the separation of the columnar granules and reduced interlayer interaction between Co–HfN granular layers via a HfN interlayer.

  5. Grindability of cast Ti-Hf alloys.

    PubMed

    Kikuchi, Masafumi; Takahashi, Masatoshi; Sato, Hideki; Okuno, Osamu; Nunn, Martha E; Okabe, Toru

    2006-04-01

    As part of our systematic studies characterizing the properties of titanium alloys, we investigated the grindability of a series of cast Ti-Hf alloys. Alloy buttons with hafnium concentrations up to 40 mass% were made using an argon-arc melting furnace. Each button was cast into a magnesia-based mold using a dental titanium casting machine; three specimens were made for each metal. Prior to testing, the hardened surface layer was removed. The specimens were ground at five different speeds for 1 min at 0.98 N using a carborundum wheel on an electric dental handpiece. Grindability was evaluated as the volume of metal removed per minute (grinding rate) and the volume ratio of metal removed compared to the wheel material lost (grinding ratio). The data were analyzed using ANOVA. A trend of increasing grindability was found with increasing amounts of hafnium, although there was no statistical difference in the grindability with increasing hafnium contents. We also found that hafnium may be used to harden or strengthen titanium without deteriorating the grindability.

  6. Ionospheric heating with oblique HF waves

    NASA Astrophysics Data System (ADS)

    Field, Edward C., Jr.; Bloom, Ron M.

    1990-10-01

    Calculations of ionospheric electron density perturbations and ground-level signal changes produce by intense oblique high frequency (HF) transmitters are presented. This analysis considers radio field focusing at caustics, the consequent joule-heating of the surrounding plasma, heat conduction, diffusion, and recombination processes: these being the effects of a powerful oblique 'modifying' wave. It neglects whatever plasma instabilities might occur. Then effects on a secondary 'test' wave that is propagated along the same path as the first are investigated. Calculations predict ground-level field-strength reductions of several dB in the test wave for modifying waves having ERP in the 85 to 90 dBW range. These field-strength changes are similar in sign, magnitude, and location to ones measured in Soviet experiments. The results are sensitive to the model ionosphere assumed, so future experiments should employ the widest possible range of frequencies and propagation conditions. An effective power of 90 dBW seems to be a sort of threshold that, if exceeded, results in substantial rather than small signal changes. The conclusions are based solely on joule-heating and subsequent defocusing of waves passing through caustic regions.

  7. Pulsed HF laser ablation of dentin

    NASA Astrophysics Data System (ADS)

    Papagiakoumou, Eirini I.; Papadopoulos, Dimitris N.; Makropoulou, Mersini I.; Khabbaz, Maruan G.; Serafetinides, Alexander A.

    2005-03-01

    The interaction of a TEA (Transversally Excited Atmospheric pressure) corona preionized oscillator double amplifier HF (hydrogen fluoride) laser beam with dentin tissue is reported. Pulses of 39 ns in the wavelength range of 2.65-3.35 μm and output energies in the range of 10-45 mJ, in a predominantly TEM00 beam were used to interact with dentin tissue. Ablation experiments were conducted with the laser beam directly focused on the tissue. Several samples of freshly extracted human teeth were used, cut longitudinally in facets of about 1mm thick and stored in phosphate buffered saline after being cleaned from the soft tissue remains. The experimental data (ablation thresholds, ablation rates) are discussed with respect to the ablation mechanism(s). Adequate tissue removal was observed and the ablation behavior was, in the greates part of the available fluences, almost linear. From the microscopic examination of teh samples, in a scanning electron microscope (SEM), the irradiated surfaces displayed oval craters (reflecting the laser beam shape) with absence of any melting or carbonization zone. It is suggested that the specific laser removes hard tissue by a combined photothermal and plasma mediated ablation mechanism, leaving a surface free from thermal damage and with a well-shaped crater.

  8. Low-Frequency Waves in HF Heating of the Ionosphere

    NASA Astrophysics Data System (ADS)

    Sharma, A. S.; Eliasson, B.; Milikh, G. M.; Najmi, A.; Papadopoulos, K.; Shao, X.; Vartanyan, A.

    2016-02-01

    Ionospheric heating experiments have enabled an exploration of the ionosphere as a large-scale natural laboratory for the study of many plasma processes. These experiments inject high-frequency (HF) radio waves using high-power transmitters and an array of ground- and space-based diagnostics. This chapter discusses the excitation and propagation of low-frequency waves in HF heating of the ionosphere. The theoretical aspects and the associated models and simulations, and the results from experiments, mostly from the HAARP facility, are presented together to provide a comprehensive interpretation of the relevant plasma processes. The chapter presents the plasma model of the ionosphere for describing the physical processes during HF heating, the numerical code, and the simulations of the excitation of low-frequency waves by HF heating. It then gives the simulations of the high-latitude ionosphere and mid-latitude ionosphere. The chapter also briefly discusses the role of kinetic processes associated with wave generation.

  9. 12. Hard HF transmitter antenna, view toward west. Lyon ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    12. Hard HF transmitter antenna, view toward west. Lyon - Whiteman Air Force Base, Oscar O-1 Minuteman Missile Alert Facility, Southeast corner of Twelfth & Vendenberg Avenues, Knob Noster, Johnson County, MO

  10. 11. Hard HF receiver antenna, view towards east. Lyon ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    11. Hard HF receiver antenna, view towards east. Lyon - Whiteman Air Force Base, Oscar O-1 Minuteman Missile Alert Facility, Southeast corner of Twelfth & Vendenberg Avenues, Knob Noster, Johnson County, MO

  11. Sequential sputtered Co-HfO2 granular films

    NASA Astrophysics Data System (ADS)

    Chadha, M.; Ng, V.

    2017-03-01

    A systematic study of magnetic, magneto-transport and micro-structural properties of Co-HfO2 granular films fabricated by sequential sputtering is presented. We demonstrate reduction in ferromagnetic-oxide formation by using HfO2 as the insulting matrix. Microstructure evaluation of the films showed that the film structure consisted of discrete hcp-Co grains embedded in HfO2 matrix. Films with varying compositions were prepared and their macroscopic properties were studied. We correlate the variation in these properties to the variation in film microstructure. Our study shows that Co-HfO2 films with reduced cobalt oxide and varying properties can be prepared using sequential sputtering technique.

  12. EPA study on HF acid could spell trouble for refiners

    SciTech Connect

    Lobsenz, G.

    1993-06-30

    Hydrofluoric acid, a highly toxic substance used at petroleum refineries, uranium fuel fabrication plants and many other industrial plants, could cause {open_quotes}severe impacts{close_quotes} more than six miles downwind of a worst-case accident, according to preliminary findings of an Environmental Protection Agency study. The study, also found that local governments and communities near some HF facilities were largely unaware of the serious risks posed by an HF release and the protective measures that were needed. HF is present at hundreds of industrial facilities nationwide, including petroleum refineries, where it is used to produce clean-burning gasoline, uranium fuel fabrication facilities and manufacturers of refrigerants, electronics, detergents and drugs. Among other issues, petroleum refiners are strongly concerned about suggestions from environmentalists that EPA consider requiring the industry to phase out HF alkylation units and replace them with an alternative process using sulfuric acid.

  13. Lu-Hf constraints on the evolution of lunar basalts

    NASA Technical Reports Server (NTRS)

    Fujimaki, H.; Tatsumoto, M.

    1984-01-01

    It is shown that a cumulate-remelting model best explains the recently acquired data on the Lu-Hf systematics of lunar mare basalts. The model is constructed using Lu and Hf concentration data and is strengthened by Hf isotopic evidence of Unruh et al. (1984). It is shown that the similarity in MgO/FeO ratios and Cr2O3 content in high-Ti and low-Ti basalts are not important constraints on lunar basalt petrogenesis. The model demonstrates that even the very low Ti or green glass samples are remelting products of a cumulate formed after at least 80-90 percent of the lunar magma ocean had solidified. In the model, all the mare basalts and green glasses were derived from 100-150 km depth in the lunar mantle. The Lu-Hf systematics of KREEP basalts clearly indicate that they would be the final residual liquid of the lunar magma ocean.

  14. Superconducting properties of the noncentrosymmetric superconductor Re6Hf

    NASA Astrophysics Data System (ADS)

    Singh, D.; Hillier, A. D.; Thamizhavel, A.; Singh, R. P.

    2016-08-01

    We report synthesis and detailed characterization of the noncentrosymmetric superconductor Re6Hf using powder x-ray diffraction (XRD), magnetization, transport, and thermodynamic measurements. XRD confirmed the noncentrosymmetric, α -Mn cubic structure in Re6Hf with the cubic cell parameter a =9.6850 (3 ) Å. Resistivity, DC, and AC magnetization measurements confirmed the type-II superconductivity in Re6Hf with the transition temperature Tconset˜5.96 K, having the lower critical field Hc 1(0 ) 5.6 mT and upper critical field Hc 2(0 ) 12.2 T. The electronic specific heat data fits well with the single-gap BCS model. The Sommerfeld coefficient (γ ) also shows linear relation with the magnetic field. All above results suggest s -wave superconductivity in Re6Hf .

  15. Theoretical Assessment of 178m2Hf De-Excitation

    SciTech Connect

    Hartouni, E P; Chen, M; Descalle, M A; Escher, J E; Loshak, A; Navratil, P; Ormand, W E; Pruet, J; Thompson, I J; Wang, T F

    2008-10-06

    This document contains a comprehensive literature review in support of the theoretical assessment of the {sup 178m2}Hf de-excitation, as well as a rigorous description of controlled energy release from an isomeric nuclear state.

  16. Spectroscopic constants and potential energy curves of HfH

    NASA Astrophysics Data System (ADS)

    Balasubramanian, K.; Das, Kalyan K.

    1991-01-01

    Complete active space multiconfiguration self-consistent field (CAS-MCSFC) followed by full second-roder CI (SOCI) and relativistic configuration interaction (RCI) including spin-orbit coupling calculations are carried out on 14 λ- s and 10 ω-ω states of HfH. The spectroscopic constants ( re, Te, ωe, μe, De) of these states are computed. The potential energy curves of these states are also reported. We find several electronic transitions in the IR-UV regions for HfH which are yet to be observed. The ground state of HfH is found to be a {3}/{2} state (82% 2Δ, 8% 2Π) with r e = 1.854 Å, ωe = 1704 cm -1 and μe = 0.66 D. The spin-orbit effects are found to be very significant for HfH.

  17. Application of HF radar currents to oil spill modelling.

    PubMed

    Abascal, Ana J; Castanedo, Sonia; Medina, Raul; Losada, Inigo J; Alvarez-Fanjul, Enrique

    2009-02-01

    In this work, the benefits of high-frequency (HF) radar currents for oil spill modeling and trajectory analysis of floating objects are analyzed. The HF radar performance is evaluated by means of comparison between a drifter buoy trajectory and the one simulated using a Lagrangian trajectory model. A methodology to optimize the transport model performance and to calculate the search area of the predicted positions is proposed. This method is applied to data collected during the Galicia HF Radar Experience. This experiment was carried out to explore the capabilities of this technology for operational monitoring along the Spanish coast. Two long-range HF radar stations were installed and operated between November 2005 and February 2006 on the Galician coast. In addition, a drifter buoy was released inside the coverage area of the radar. The HF radar currents, as well as numerical wind data were used to simulate the buoy trajectory using the TESEO oil spill transport model. In order to evaluate the contribution of HF radar currents to trajectory analysis, two simulation alternatives were carried out. In the first one, wind data were used to simulate the motion of the buoy. In the second alternative, surface currents from the HF radar were also taken into account. For each alternative, the model was calibrated by means of the global optimization algorithm SCEM-UA (Shuffled Complex Evolution Metropolis) in order to obtain the probability density function of the model parameters. The buoy trajectory was computed for 24h intervals using a Monte Carlo approach based on the results provided in the calibration process. A bivariate kernel estimator was applied to determine the 95% confidence areas. The analysis performed showed that simulated trajectories integrating HF radar currents are more accurate than those obtained considering only wind numerical data. After a 24h period, the error in the final simulated position improves using HF radar currents. Averaging the

  18. Acute-on-chronic Liver Failure.

    PubMed

    Sarin, Shiv Kumar; Choudhury, Ashok

    2016-12-01

    Acute-on-chronic liver failure (ACLF) is a distinct entity that differs from acute liver failure and decompensated cirrhosis in timing, presence of treatable acute precipitant, and course of disease, with a potential for self-recovery. The core concept is acute deterioration of existing liver function in a patient of chronic liver disease with or without cirrhosis in response to an acute insult. The insult should be a hepatic one and presentation in the form of liver failure (jaundice, encephalopathy, coagulopathy, ascites) with or without extrahepatic organ failure in a defined time frame. ACLF is characterized by a state of deregulated inflammation. Initial cytokine burst presenting as SIRS, progression to CARS and associated immunoparalysis leads to sepsis and multi-organ failure. Early identification of the acute insult and mitigation of the same, use of nucleoside analogue in HBV-ACLF, steroid in severe alcoholic hepatitis, steroid in severe autoimmune hepatitis and/or bridging therapy lead to recovery, with a 90-day transplant-free survival rate of up to 50 %. First-week presentation is crucial concerning SIRS/sepsis, development, multiorgan failure and consideration of transplant. A protocol-based multi-disciplinary approach including critical care hepatology, early liver transplant before multi-organ involvement, or priority for organ allocation may improve the outcome. Presentation with extrahepatic organ involvement or inclusion of sepsis as an acute insult in definition restricts the therapy, i.e., liver transplant or bridging therapy, and needs serious consideration. Augmentation of regeneration, cell-based therapy, immunotherapy, and gut microbiota modulation are the emerging areas and need further research.

  19. Incidence of and factors associated with hepatocellular carcinoma among hepatitis C virus and human immunodeficiency virus coinfected patients with decompensated cirrhosis.

    PubMed

    García-García, José A; Romero-Gómez, Manuel; Girón-González, José A; Rivera-Irigoin, Robin; Torre-Cisneros, Julián; Montero, José L; González-Serrano, Mercedes; Andrade, Raúl J; Aguilar-Guisado, Manuela; Grilo, Israel; Martín-Vivaldi, Javier; Salmerón, Javier; Caballero-Granado, Francisco J; Macías, Juan; Vergara-López, Salvador; Pineda, Juan A

    2006-12-01

    We compared the incidence of and factors associated with hepatocellular carcinoma (HCC) among hepatitis C virus (HCV)-monoinfected subjects and human immunodeficiency virus (HIV)/HCV-coinfected individuals, both with decompensated cirrhosis. In a retrospective study, a cohort of 180 individuals with HIV coinfection and 1037 HCV-monoinfected patients with decompensated HCV-related cirrhosis from eight centres in Spain were analyzed. HCC was found in 234 (23%) HCV-monoinfected subjects and in four (2%) HIV-coinfected subjects (p<0.001). At the time of the first hepatic decompensation, 188 (17%) and 4 (2%) (p<0.001) patients in the former and in the latter group, respectively, showed HCC. Fifty-four (11%) patients without HCC at baseline developed such a disease during follow-up. There were no incident cases among the HIV-coinfected population. The density of incidence (95% IC) of HCC in HIV/HCV-coinfected and HCV-monoinfected patients was 0 (0-1.70) and 3.31 (2.70-4.64) cases per 100 person-years (p<0.001), respectively. Lack of HIV infection [adjusted odds risk (AOR) (95% IC)=16.7 (3.9-71.1)] and high alanine aminotransferase levels [AOR (95% IC)=2.5 (1.1-5)] were the only two independent predictors of the emergence of HCC. In the group of patients in whom the date of HCV infection could be estimated, the time elapsed until HCC diagnosis was shorter among HIV-coinfected subjects. The incidence of HCC in patients with HCV-related cirrhosis after the first hepatic decompensation is lower in HIV-coinfected patients. This is probably due to the fact that HIV infection shortens the survival of HCV-coinfected patients with end-stage liver disease to such an extent that HCC not had a chance to emerge.

  20. Characterization of an HF-Pumped CO2 Laser.

    DTIC Science & Technology

    1981-10-01

    the 101 and 100 energy levels and lasing action is achieved at 4.3 microns. The results of a theoretical analysis and an experimental study are used...14 3 Predicted HF Power Pulse Shape .................. 30 4 Optical Pumping Schemes ......................... 31 5 CO2 Energy Level Diaqram...32 6 12C1802 Energy Level Diagram .................... 34 7 HF and CO2 Line Broadeninq ....................... 36 8 CO Absorption

  1. Propagation Impact on Modern HF (High Frequency) Communications System Design

    DTIC Science & Technology

    1986-03-01

    to 2.4 kbits/s and above - in the same way as with line circuits or other less dispersive media . However, as will be shown in Section 2, the capacity...time interval. (c) An assumption that HF communication can replace, or back-up, other types of less dispersive communication media and still...reliable. The following media may be considered for interconnection purposes: (a) HF skywave and surface-wave point-to-point links; (b) meteor

  2. Monitoring the HF spectrum in the presence of noise

    NASA Astrophysics Data System (ADS)

    Giesbrecht, James E.; Clarke, Russell; Abbott, Derek

    2004-05-01

    This paper reviews modulation recognition in the context of HF radio-communications. We investigate entropic distance measures and coherence measures for recognizing HF modulations. Preliminary results shown that it may be possible to identify a modulation and its transmit power level based on the entropic distance between it and another modulation. Coherence estimates may provide characteristic signatures that can be used to identify modulation types.

  3. [Organ-protection therapy. A new therapeutic approach for acute heart failure?].

    PubMed

    Chivite, David; Formiga, Francesc; Corbella, Xavier

    2014-03-01

    Unlike the prolonged benefit produced by the treatment of chronic heart failure, newer drugs tested for the treatment of acute heart failure in the last decade have failed to provide evidence of clinical benefit beyond some improvement in symptom relief. In particular, no drug has shown the ability to reduce the higher medium- and long-term risk of morbidity and mortality in these patients after an episode of decompensation. Current understanding of the pathophysiology of acute heart failure and its consequences has led to the hypothesis that, beyond symptom control, effective therapies for this syndrome should target not only the hemodynamic changes of the initial phase of the syndrome but should also "protect" the organism from the activation of neurohumoral and inflammatory pathways triggered by the decompensation episode, which persist in time and confer a risk of deleterious effects in several organs and tissues. Serelaxin, a new drug related to the peptidic endogenous hormones of the relaxin family, has recently been shown to provide multiple beneficial effects in terms of "organ protection" - not only in the cardiovascular and renal systems - from these acute heart failure-related deleterious changes. This drug has already been tested in acute heart failure patients with encouraging results in terms of medium-term clinical benefit, rendering serelaxin as a serious candidate for first-line, prognosis-modifying therapy in this syndrome.

  4. Heparin Saline Versus Normal Saline for Flushing and Locking Peripheral Venous Catheters in Decompensated Liver Cirrhosis Patients

    PubMed Central

    Wang, Rui; Zhang, Ming-Guang; Luo, Ou; He, Liu; Li, Jia-Xin; Tang, Yun-Jing; Luo, Yan-Li; Zhou, Min; Tang, Li; Zhang, Zong-Xia; Wu, Hao; Chen, Xin-Zu

    2015-01-01

    Abstract A prospective randomized, controlled, single-blinded trial to compare the effectiveness and safety of heparin saline (HS) to those of normal saline (NS) as flushing and locking solutions for peripheral venous catheter (PVC) in decompensated liver cirrhosis (DLC) patients. Patients with DLC at our institution between April 2012 and March 2013 were enrolled after obtaining informed consent. The patients were randomly allocated into 2 groups: the NS group received preservative-free 0.9% sodium chloride as the flushing and locking solution, while the HS group received HS (50 U/mL). PVC-related events and the duration of PVC maintenance were compared between the 2 groups. Moreover, the preinfusion and postinfusion levels of prothrombin time (PT), activated partial thromboplastin time (APTT), and platelet (PLT) were also compared. A total of 32 and 36 DLC patients in the NS (125 PVCs) and HS (65 PVCs) groups, respectively, were analyzed. Baseline characteristics, including gender, age, Child–Pugh grade, PVC type and administration of anticoagulant, and irritant agents, were comparable between the 2 groups (P > 0.05). The maintenance times of the HS and NS groups were 80.27 ± 26.47 and 84.19 ± 29.32 hours, respectively (P = 0.397). Removal of PVC for abnormal reasons occurred in 30.7% and 22.4% of patients in the HS and NS groups (P = 0.208). The PVC occlusion rates were 6.2% and 5.6% in the HS and NS groups, respectively (OR = 1.11, 95% CI 0.31–3.92). The PT, APTT, and PLT levels were comparable between the 2 groups both before and after infusion (P > 0.05). Incremental analyses showed that Child–Pugh grade C might be a risk factor for the suppression of PLT in the HS group. We consider NS to be as effective as and safer than conventional HS for flushing and locking PVC in decompensated liver cirrhosis patients. PMID:26252305

  5. Temperature Dependence of Vibrational Relaxation from the Upper Vibrational Levels of HF and DF.

    DTIC Science & Technology

    1980-08-29

    dependent quenching rate coefficients for relaxation of HF(v) and DF(v) by HF(v = 0) and DF(v = 0). The temperature dependence is predicted to be...halide molecules. This theoretical study is the first in which the temperature dependence of the V to R rate coefficients for HF(v sub 1) + HF(v sub 2

  6. The isobutylene-isobutane alkylation process in liquid HF revisited.

    PubMed

    Esteves, P M; Araújo, C L; Horta, B A C; Alvarez, L J; Zicovich-Wilson, C M; Ramírez-Solís, A

    2005-07-07

    Details on the mechanism of HF catalyzed isobutylene-isobutane alkylation were investigated. On the basis of available experimental data and high-level quantum chemical calculations, a detailed reaction mechanism is proposed taking into account solvation effects of the medium. On the basis of our computational results, we explain why the density of the liquid media and stirring rates are the most important parameters to achieve maximum yield of alkylate, in agreement with experimental findings. The ab initio Car-Parrinello molecular dynamics calculations show that isobutylene is irreversibly protonated in the liquid HF medium at higher densities, leading to the ion pair formation, which is shown to be a minimum on the potential energy surface after optimization using periodic boundary conditions. The HF medium solvates preferentially the fluoride anion, which is found as solvated [FHF](-) or solvated F(-.)(HF)(3). On the other hand, the tert-butyl cation is weakly solvated, where the closest HF molecules appear at a distance of about 2.9 Angstrom with the fluorine termination of an HF chain.

  7. Thermal stability of HfO2 nanotube arrays

    SciTech Connect

    Qiu, Xiaofeng; Howe, Jane Y; Meyer III, Harry M; Tuncer, Enis; Paranthaman, Mariappan Parans

    2010-01-01

    Thermal stability of highly ordered hafnium oxide (HfO2) nanotube arrays prepared through an electrochemical anodization method in the presence of ammonium fluoride is investigated in a temperature range of room temperature to 900 C in flowing argon atmosphere. The formation of the HfO2 nanotube arrays was monitored by current density transient characteristics during anodization of hafnium metal foil. Morphologies of the as-grown and post-annealed HfO2 nanotube arrays were analyzed by powder Xray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Although monoclinic HfO2 is thermally stable up to 2000K in bulk, the morphology of HfO2 nanotube arrays degraded at 900 C. A detailed X-ray photoelectron spectroscopy (XPS) study revealed that the thermal treatment significantly impacted the composition and the chemical environment of the core elements (Hf and O), as well as F content coming from the electrolyte. Possible reasons for the degradation of the nanotube at high temperature were discussed based on XPS study and possible future improvements have also been suggested. Moreover, dielectric measurements were carried out on both the as-grown amorphous film and 500 C post-annealed crystalline film. This study will help us to understand the temperature impact on the morphology of nanotube arrays, which is important to its further applications at elevated temperatures.

  8. Three-dimensional analysis of dental decompensation for skeletal Class III malocclusion on the basis of vertical skeletal patterns obtained using cone-beam computed tomography

    PubMed Central

    Kim, Yong-Il; Choi, Youn-Kyung; Son, Woo-Sung; Kim, Seong-Sik

    2012-01-01

    Objective To evaluate the presurgical orthodontic tooth movement of mandibular teeth after dental decompensation for skeletal Class III deformities on the basis of vertical skeletal patterns. Methods This cohort was comprised of 62 patients who received presurgical orthodontic treatment. These patients were divided into 3 groups according to their vertical skeletal patterns. Changes in the positions of the mandibular central incisor, canine, premolar, and 1st molar after presurgical orthodontic treatment were measured using a cone-beam computed tomography (CBCT) superimposition method. Results The incisors moved forward after dental decompensation in all 3 groups. The canines in group I and the 1st premolars in groups I and III also moved forward. The incisors and canines were extruded in groups I and II. The 1st and 2nd premolars were also extruded in all groups. Vertical changes in the 1st premolars differed significantly between the groups. We also observed lateral movement of the canines in group III and of the 1st premolar, 2nd premolar, and 1st molar in all 3 groups (p < 0.05). Conclusions Movement of the mandibular incisors and premolars resolved the dental compensation. The skeletal facial pattern did not affect the dental decompensation, except in the case of vertical changes of the 1st premolars. PMID:23173115

  9. Tracking magmatic processes through Zr/Hf ratios in rocks and Hf and Ti zoning in zircons: An example from the Spirit Mountain batholith, Nevada

    USGS Publications Warehouse

    Lowery, Claiborne L.E.; Miller, C.F.; Walker, B.A.; Wooden, J.L.; Mazdab, F.K.; Bea, F.

    2006-01-01

    Zirconium and Hf are nearly identical geochemically, and therefore most of the crust maintains near-chondritic Zr/Hf ratios of ???35-40. By contrast, many high-silica rhyolites and granites have anomalously low Zr/Hf (15-30). As zircon is the primary reservoir for both Zr and Hf and preferentially incorporates Zr, crystallization of zircon controls Zr/ Hf, imprinting low Zr/Hf on coexisting melt. Thus, low Zr/Hf is a unique fingerprint of effective magmatic fractionation in the crust. Age and compositional zonation in zircons themselves provide a record of the thermal and compositional histories of magmatic systems. High Hf (low Zr/ Hf) in zircon zones demonstrates growth from fractionated melt, and Ti provides an estimate of temperature of crystallization (TTiZ) (Watson and Harrison, 2005). Whole-rock Zr/Hf and zircon zonation in the Spirit Mountain batholith, Nevada, document repeated fractionation and thermal fluctuations. Ratios of Zr/Hf are ???30-40 for cumulates and 18-30 for high-SiO2 granites. In zircons, Hf (and U) are inversely correlated with Ti, and concentrations indicate large fluctuations in melt composition and TTiZ (>100??C) for individual zircons. Such variations are consistent with field relations and ion-probe zircon geochronology that indicate a >1 million year history of repeated replenishment, fractionation, and extraction of melt from crystal mush to form the low Zr/Hf high-SiO2 zone. ?? 2006 The Mineralogical Society.

  10. Global potential energy hypersurface for dynamical studies of energy transfer in HF--HF collisions

    SciTech Connect

    Redmon, M.J.; Binkley, J.S.

    1987-07-15

    The interaction energy of two HF molecules at 1332 individual points has been calculated with Moeller--Plesset (many--body) perturbation theory at the MP4-SDTQ level using a 6-311G** basis set. 293 of the points correspond to stretching of one HF molecule from its equilibrium geometry. No attempt was made to use a sufficiently fine grid to accurately describe the well region corresponding to hydrogen bonding. However, the location and minimum energy are consistent with experiment and other accurate theoretical results. An extensive global fit (rms error of 1 kcal/mol) is reported of 1319 points (below 10 eV of potential energy) using a modified London potential with corrections obtained using polynomials through four-body interactions. A model electrostatic potential represents the long-range interaction. In addition, the use of an expansion in products of three Legendre functions is discussed. It is shown that the latter approach, although accurately fitting the ab initio data, has difficulties interpolating in regions of the surface exhibiting diverse magnitudes of potential energy, and therefore must be used with caution. This surface should be useful for studies of T--V--R processes in this system.

  11. Role of Hf on Phase Formation in Ti45Zr(38-x)Hf(x)Ni17 Liquids and Solids

    NASA Technical Reports Server (NTRS)

    Wessels, V.; Sahu, K. K.; Gangopadhyay, A. K.; Huett, V. T.; Canepari, S.; Goldman, A. I.; Hyers, R. W.; Kramer, M. J.; Rogers, J. R.; Kelton, K. F.; Robinson, D.

    2008-01-01

    Hafnium and zirconium are very similar, with almost identical sizes and chemical bonding characteristics. However, they behave differently when alloyed with Ti and Ni. A sharp phase formation boundary near 18-21 at.% Hf is observed in rapidly-quenched and as-cast Ti45Zr38-xHfxNi17 alloys. Rapidly-quenched samples that contain less than 18 at.% Hf form the icosahedral quasicrystal phase, whiles samples containing more than 21 at.% form the 3/2 rational approximant phase. In cast alloys, a C14 structure is observed for alloys with Hf lower than the boundary concentration, while a large-cell (11.93 ) FCC Ti2Ni-type structure is found in alloys with Hf concentrations above the boundary. To better understand the role of Hf on phase formation, the structural evolution with supercooling and the solidification behavior of liquid Ti45Zr38-xHfxNi17 alloys (x=0, 12, 18, 21, 38) were studied using the Beamline Electrostatic Levitation (BESL) technique using 125keV x-rays on the 6ID-D beamline at the Advanced Photon Source, Argonne National Laboratory. For all liquids primary crystallization was to a BCC solid solution phase; interestly, an increase in Hf concentration leads to a decrease in the BCC lattice parameter in spite of the chemical similarity between Zr and Hf. A Reitveld analysis confirmed that as in the cast alloys, the secondary phase that formed was the C14 below the phase formation boundary and a Ti2Ni-type structure at higher Hf concentrations. Both the liquidus temperature and the reduced undercooling change sharply on traversing the phase formation boundary concentration, suggesting a change in the liquid structure. Structural information from a Honeycutt-Anderson index analysis of reverse Monte Carlo fits to the S(q) liquid data will be presented to address this issue.

  12. Cystitis - acute

    MedlinePlus

    Uncomplicated urinary tract infection; UTI - acute cystitis; Acute bladder infection; Acute bacterial cystitis ... cause. Menopause also increases the risk for a urinary tract infection. The following also increase your chances of having ...

  13. Serpentinization Changes Nd, but not Hf Isotopes of Abyssal Peridotites

    NASA Astrophysics Data System (ADS)

    Bizimis, M.; Frisby, C. P.; Mallick, S.

    2015-12-01

    Serpentinization of the oceanic lithosphere is a known sink for fluid mobile elements (B, Cl, Li, Sr, etc.), while high field strength elements (HFSE: e.g., Hf, Zr, Ti, Nb) are thought to be unaffected by it. In contrast, the fate of REE during serpentinization is equivocal. Correlations between REE and HFSE concentrations in abyssal peridotites suggest control by magmatic processes (Niu, 2004, J. Pet), while some LREE enrichments in serpentinized peridotites compared to their clinopyroxene (cpx) and Nd, Sr isotope data (Delacour et al., 2008, Chem. Geol.) imply seawater-derived REE addition to the mantle protolith (Paulick et al., 2006, Chem. Geol). To further constrain peridotite-seawater interaction during serpentinization we compare bulk rock and cpx Hf and Nd isotope data in partially (up to ~70%) serpentinized abyssal peridotites (9-16°E South West Indian Ridge). We also present a new method that improves yields in Hf, Nd and Pb separations from depleted (<0.03 ppm Hf) ultramafic rocks, which includes coprecipitation of metals with Al-Fe hydroxides and ether-HCl liquid-liquid exchange for Fe removal. Nd isotopes in the bulk peridotite are up to 7ɛNd units less radiogenic than their cpx (i.e., the magmatic value) while Hf isotopes remain equal to cpx within 1 ɛHf. Melt-rock reaction by the local lavas cannot generate this decoupling. The largest Nd isotopic difference between cpx and bulk is seen in the most LREE-depleted samples, while refertilized samples show little change. Leaching experiments show that 30-60% of REE are mobilized from the rock, but >90% of Hf, Zr, Ti are retained in the residue. LA-ICPMS data shows that serpentine after olivine typically has higher LREE/HREE ratios than cpx, pronounced negative Ce anomalies, high U, Sr concentrations and low HFSE, unlike the coexisting cpx. These data are consistent with some seawater-derived LREE addition to peridotite during serpentinization, localized in the serpentine and other secondary phases

  14. Serum C-reactive protein predicts early mortality in hospitalized patients with HBV-related decompensated cirrhosis

    PubMed Central

    Zhu, ShaoMing; Waili, Yulituzi; Qi, XiaoTing; Chen, YueMei; Lou, YuFeng; Chen, Bo

    2017-01-01

    Abstract The serum C-reactive protein (CRP) is an inflammatory marker. The aim of the present study was to elucidate whether CRP could serve as a potential surrogate marker for 30-day mortality in hospitalized patients with HBV-related decompensated cirrhosis (HBV-DeCi). This was a retrospective cohort study that included 140 patients with HBV-DeCi. All patients were followed up for 1-month. A panel of clinical and biochemical variables were analyzed for potential associations with outcomes using multiple regression models. The serum CRP was significantly higher in nonsurviving patients than in surviving patients. Multivariate analysis demonstrated that CRP levels (odds ratio: 1.047, P = 0.002) and the model for end-stage liver disease score (odds ratio: 1.370, P = 0.001) were independent predictors for mortality. Serum CRP is a simple marker that may serve as an additional predictor of 1-month mortality in hospitalized patients with HBV-DeCi. PMID:28121954

  15. Serum C-reactive protein predicts early mortality in hospitalized patients with HBV-related decompensated cirrhosis.

    PubMed

    Zhu, ShaoMing; Waili, Yulituzi; Qi, XiaoTing; Chen, YueMei; Lou, YuFeng; Chen, Bo

    2017-01-01

    The serum C-reactive protein (CRP) is an inflammatory marker. The aim of the present study was to elucidate whether CRP could serve as a potential surrogate marker for 30-day mortality in hospitalized patients with HBV-related decompensated cirrhosis (HBV-DeCi).This was a retrospective cohort study that included 140 patients with HBV-DeCi. All patients were followed up for 1-month. A panel of clinical and biochemical variables were analyzed for potential associations with outcomes using multiple regression models.The serum CRP was significantly higher in nonsurviving patients than in surviving patients. Multivariate analysis demonstrated that CRP levels (odds ratio: 1.047, P = 0.002) and the model for end-stage liver disease score (odds ratio: 1.370, P = 0.001) were independent predictors for mortality.Serum CRP is a simple marker that may serve as an additional predictor of 1-month mortality in hospitalized patients with HBV-DeCi.

  16. Sustained clinical improvement of a patient with decompensated hepatitis B virus-related cirrhosis after treatment with lamivudine monotherapy.

    PubMed

    Nagasaki, Futoshi; Ueno, Yoshiyuki; Yamamoto, Takeshi; Nakagomi, Yu; Kido, Osamu; Kakazu, Eiji; Matsuda, Yasunori; Kogure, Takayuki; Yamagiwa, Yoko; Kikuchi, Kumiko; Fukushima, Koji; Kanno, Noriatsu; Niitsuma, Hirofumi; Shimosegawa, Tooru

    2006-09-01

    Hepatitis B virus (HBV) infection, which causes liver cirrhosis and hepatocellular carcinoma, remains a major health problem in Asian countries. Recent development of vaccine for prevention is reported to be successful in reducing the size of chronically infected carriers, although the standard medical therapies have not been established up to now. In this report, we encountered a patient with decompensated HBV-related cirrhosis who exhibited the dramatic improvements after antiviral therapy. The patient was a 50-year-old woman. Previous conventional medical treatments were not effective for this patient, thus this patient had been referred to our hospital. However, the administration of lamivudine, a reverse transcriptase inhibitor, for 23 months dramatically improved her liver severity. During this period, no drug resistant mutant HBV emerged, and the serum HBV-DNA level was continuously suppressed. These virological responses were also maintained even after the antiviral therapy was discontinued. Moreover, both hepatitis B surface antigen and e antigen were observed to have disappeared in this patient. The administration of lamivudine to patients with HBV-related cirrhosis, like our present case, should be considered as an initial medical therapeutic option, especially in countries where liver transplantation is not reliably available.

  17. Traditional applications and novel approaches in Lu-Hf geochronology

    NASA Astrophysics Data System (ADS)

    Herwartz, D.; Nagel, T. J.; Sandmann, S.; Vitale Brovarone, A.; Rexroth, S.; Rojas-Agramonte, Y.; Froitzheim, N.; Kröner, A.; Skublov, S. G.; Münker, C.

    2012-04-01

    Lutetium-Hf geochronology is currently becoming a routine method for dating metamorphism of garnet bearing rocks, such as eclogites. Prograde garnet growth ages are mostly preserved because blocking temperatures exceed 630 °C [1] and prograde Lu zoning patterns have even been observed in samples that were exposed to temperatures above 800 °C [2]. Here we discuss Lu-Hf ages from various eclogite localities, such as the Northern Tianshan, Kyrgyzstan (~ 470 Ma), the Kola Peninsula, Russia (~ 1900 Ma) [3], Cuba (~70 Ma and ~124 Ma), Alpine Corsica (~ 34 Ma) and the Tauern Window (~32.7 Ma). Age precisions are in the order of 0.1 to 1 % and all ages can be safely attributed to the timing of garnet growth. Some samples, however, contain two garnet populations which complicates Lu-Hf geochronology. In the Adula Nappe (Central Alps) relict garnet has survived a second orogenic cycle, including subduction to mantle depth. By carefully separating the two garnet populations present within the same eclogite sample we obtained a minimum Variscan age of 333 Ma and a maximum Alpine age of 38 Ma [4]. A similar relationship is now evident in samples from the Tauern Window (Eastern Alps), where only one population of garnet generation is visible macroscopically. However, few relics of Variscan garnet inside Alpine garnet are observed in electron microprobe element maps and are also evident from isotopic heterogeneity in 176Lu/177Hf vs. 176Hf/177Hf space. Garnet relics stemming from previous metamorphic events are frequently observed in HP units around the world and the Lu-Hf system is a promising tool to resolve the respective growth ages. Apart from garnet, lawsonite Lu-Hf geochronology was recently identified as a new tool to investigate subduction processes [5]. Here we present a lawsonite Lu-Hf isochron 37,6 ± 1.4 Ma (MSWD = 0.30; n =5) from a lawsonite blueschist from Alpine Corsica. The lawsonite slightly predates the timing of garnet growth (~34 Ma) in three eclogite

  18. HEV infection as an aetiologic factor for acute hepatitis: experience from a tertiary hospital in Bangladesh.

    PubMed

    Mamun-Al-Mahtab; Rahman, Salimur; Khan, Mobin; Karim, Fazal

    2009-02-01

    Acute hepatitis is seen sporadically round the year in Bangladesh. The incidence of acute viral hepatitis E increases after floods as this allows sewerage contamination of piped and groundwater. The aim of this retrospective study was to assess the burden of hepatitis E virus (HEV infection) in Bangladesh. Patients attending the Hepatology Unit III of the Bangabandhu Sheikh Mujib Medical University, during June 2004-December 2006, were included in the study. All viral markers were tested by enzyme-linked immunosorbent assay. The study population was divided in four groups. Group 1 included 144 patients with acute viral hepatitis. The inclusion criteria were: nausea and/or vomiting, loss of appetite, serum bilirubin >200 micromol/L, raised serum transaminases, and prothrombin time >3 seconds prolonged beyond control value. In Group 2, there were 31 pregnant women with acute viral hepatitis. All the patients had prodrome, icterus, raised serum bilirubin and raised serum transaminase levels. Group 3 included 23 patients presenting with fulminant hepatic failure. In Group 4, 69 patients with cirrhosis of liver were included. They presented with features of decompensation for the first time. The inclusion criteria were: patients with established cirrhosis with jaundice and/or ascites and/or hepatic encephalopathy. In Group 1, 58.33% of the 144 patients had acute viral hepatitis E. In Group 2, 45.16% of the pregnant women also had acute viral hepatitis E. HEV was responsible for 56.52% cases of fulminant hepatic failure in Group 3. In 21.7% cases in Group 4, decompensation of cirrhosis was due to HEV. Acute viral hepatitis E in the third trimester of pregnancy and HEV-induced fulminant hepatic failure were associated with 80% of mortality despite the best possible care. In this clinical context, acute viral hepatitis E is the leading cause of wide spectrum of liver disease ranging from severe acute viral hepatitis, fulminant hepatic failure, to decompensation of liver in

  19. Hf-Nd isotope and trace element constraints on subduction inputs at island arcs: Limitations of Hf anomalies as sediment input indicators

    NASA Astrophysics Data System (ADS)

    Handley, Heather K.; Turner, Simon; Macpherson, Colin G.; Gertisser, Ralf; Davidson, Jon P.

    2011-04-01

    New Nd-Hf isotope and trace element data for Javanese volcanoes are combined with recently published data to place constraints on subduction inputs at the Sunda arc in Indonesia and assess the value of Hf anomalies (expressed as Hf/Hf* and Sm/Hf ratios) as tracers of such inputs. Hf anomaly does not correlate with Hf isotope ratio in Javanese lavas, however, Hf/Hf* and Sm/Hf ratios do correlate with SiO 2. Contrary to previous work, we show that Hf anomaly variation may be controlled by fractionation of clinopyroxene and/or amphibole during magmatic differentiation and does not represent the magnitude or type of subduction input in some arcs. Correlation of Sm/Hf with indices of differentiation for other arcs (e.g., Vanuatu, New Britain, and Mariana) suggests that differentiation control on Sm/Hf ratios in volcanic arc rocks may be a relatively common phenomenon. This study corroborates the use of Nd-Hf isotope co-variations in arc volcanic rocks to ascertain subduction input characteristics. The trajectories of regional volcano groups (East, Central and West Java) in Nd-Hf isotope space reveal heterogeneity in the subducted sediment input along Java, which reflects present-day spatial variations in sediment compositions on the down-going plate in the Java Trench. The high Sm/Hf ratio required in the sediment end-member for some Javanese basalts suggests that partial melting of subducted sediment occurs in the presence of residual zircon, and is inconsistent with residual monazite or allanite.

  20. Investigation and Development of Data-Driven D-Region Model for HF Systems Impacts

    NASA Technical Reports Server (NTRS)

    Eccles, J. V.; Rice, D.; Sojka, J. J.; Hunsucker, R. D.

    2002-01-01

    Space Environment Corporation (SEC) and RP Consultants (RPC) are to develop and validate a weather-capable D region model for making High Frequency (HF) absorption predictions in support of the HF communications and radar communities. The weather-capable model will assimilate solar and earth space observations from NASA satellites. The model will account for solar-induced impacts on HF absorption, including X-rays, Solar Proton Events (SPE's), and auroral precipitation. The work plan includes: I . Optimize D-region model to quickly obtain ion and electron densities for proper HF absorption calculations. 2. Develop indices-driven modules for D-region ionization sources for low, mid, & high latitudes including X-rays, cosmic rays, auroral precipitation, & solar protons. (Note: solar spectrum & auroral modules already exist). 3. Setup low-cost monitors of existing HF beacons and add one single-frequency beacon. 4. Use PENEX HF-link database with HF monitor data to validate D-region/HF absorption model using climatological ionization drivers. 5. Develop algorithms to assimilate NASA satellite data of solar, interplanetary, and auroral observations into ionization source modules. 6. Use PENEX HF-link & HF-beacon data for skill score comparison of assimilation versus climatological D-region/HF absorption model. Only some satellites are available for the PENEX time period, thus, HF-beacon data is necessary. 7. Use HF beacon monitors to develop HF-link data assimilation algorithms for regional improvement to the D-region/HF absorption model.

  1. Ketogenic diet: rapid onset of selenium deficiency-induced cardiac decompensation.

    PubMed

    Sirikonda, Naga S; Patten, William D; Phillips, John R; Mullett, Charles J

    2012-06-01

    Selenium-deficiency cardiomyopathy is a known secondary complication from long-term treatment with a ketogenic diet for medical refractory epilepsy. Our patient, a 5-year-old boy on a ketogenic diet for intractable seizures, had a normal selenium level before starting the diet, but he shortly thereafter developed acute reversible cardiomyopathy and ventricular tachycardia, which was unmasked during a hospitalization for an elective operative procedure. His cardiomyopathy was suspected to be secondary to a selenium-deficient state and was confirmed by way of a markedly low serum selenium level and supported by rapid improvement with the initiation of selenium supplementation and cessation of the ketogenic diet. For patients being initiated on a ketogenic diet, current screening guidelines call for baseline and follow-up selenium levels every 3 months during the first year along with RDA selenium supplementation, which is 30 mcg/day. Most of the new ketogenic diet formulas meet this requirement. Our patient underwent elective surgery before his planned 3-month selenium level check and had potentially preventable complications. Secondary to this experience, we suggest that all patients initiated on a ketogenic diet should have a preoperative electrocardiogram (EKG), an echocardiogram, and selenium level determined before any elective surgery. These steps would prevent unnecessary perioperative morbidity and mortality.

  2. Complexities of Lu-Hf geochronology in convergent orogens

    NASA Astrophysics Data System (ADS)

    Mulcahy, S. R.; Vervoort, J. D.

    2015-12-01

    Subduction, terrane accretion, and arc magmatism leave a complex and sometimes incomplete record of metamorphism and deformation. The range of metamorphic temperatures and assemblages produced throughout the tectonic evolution of a single orogen often requires multiple isotopic systems to date distinct events. Lu-Hf geochronology, notably, has proven successful for dating metamorphism from a variety of bulk compositions spanning temperatures <350-850 C. We review the success of applying Lu-Hf geochronology in combination with other isotopic systems to date metamorphism from range of metamorphic conditions within convergent margins. We then discuss some complexities of Lu-Hf geochronology when dating samples with complicated metamorphic histories. Garnet and lawsonite isochrons often exhibit excess scatter (high MSWD's) that can be attributed to a number of factors: secondary mineral inclusions, prolonged garnet growth durations, disequilibrium at low temperatures, and polyphase metamorphic histories. Samples with high-Hf inclusions in isotopic equilibrium host phases can lead to decreased precision, but still produce meaningful ages. At high temperatures Lu-Hf ages may date peak metamorphism, cooling from peak temperatures, or result in spurious ages because of preferential retention of 176Hf over 176Lu in garnet. Despite these complexities, and perhaps because of them, new aspects of the metamorphic history may be revealed that are not readily recorded by other isotopic systems. Minerals other than garnet and lawsonite, particularly apatite, and perhaps epidote, offer exciting new possibilities for Lu-Hf geochronology. Careful fieldwork, detailed petrology and geochemistry, and collaborative efforts using multiple isotopic systems offer the best approach to solving tectonic problems in convergent orogens.

  3. High Frequency (HF) Radio Signal Amplitude Characteristics, HF Receiver Site Performance Criteria, and Expanding the Dynamic Range of HF Digital New Energy Receivers by Strong Signal Elimination

    DTIC Science & Technology

    1990-06-21

    COVERAGE PLAN AND ................................... 148 NOTCH FILTERING B. STRONG SIGNAL ELIMINATION SYSTEM ............................ 151 C... filters , and switching systems must process the entire HF spectrum without distortion. This means that designers must use special care to preserve...appear only at the antenna, impedance matching networks, filters , preamplifiers, and any superheterodyne initial stages. The RF Distribution System

  4. First-principles study of the Hf-based Heusler alloys: Hf2CoGa and Hf2CoIn

    NASA Astrophysics Data System (ADS)

    Hu, Yan; Zhang, Jian-Min

    2017-01-01

    The electronic structures and magnetic properties of the new Heusler alloys Hf2CoGa and Hf2CoIn have been studied by using the first-principles projector augmented wave (PAW) potential within the generalized gradient approximation (GGA). Both Hf2CoGa and Hf2CoIn Heusler alloys have the half-metallic character and completely (100%) spin polarization at the Fermi level (EF) and the indirect band gaps of 0.733 eV and 0.654 eV, respectively, in the minority spin channel. The total magnetic moments μt are all 2μB per formula unit, linearly scaled with the total number of valence electrons (Zt) by μt=Zt-18 and the atomic magnetic moments have localized character due to less affected by deformations. The origin of the indirect band gaps for these two new Heusler alloys is well understood. These two new Heusler alloys are the ideal candidates for spintronic devices.

  5. Comparison of HfAlO, HfO2/Al2O3, and HfO2 on n-type GaAs using atomic layer deposition

    NASA Astrophysics Data System (ADS)

    Lu, Bin; Lv, Hongliang; Zhang, Yuming; Zhang, Yimen; Liu, Chen

    2016-11-01

    Different high-permittivity (high-k) gate dielectric structures of HfO2, HfAlO, and HfO2/Al2O3 deposited on HF-etched n-GaAs using ALD have been investigated. It has been demonstrated that the stacked structure of HfO2/Al2O3 has the lowest interface state density of 8.12 × 1012eV-1 cm-2 due to the "self-cleaning" reaction process, but the sample of HfAlO shows much better frequency dispersion and much higher dielectric permittivity extracted from the C-V curves. The investigation reveals that the electrical properties of gate dielectrics are improved by introducing alumina into HfO2.

  6. HF omnidirectional spectral CW auroral radar (HF-OSCAR) at very high latitude. Part 1: Technique

    NASA Astrophysics Data System (ADS)

    Olesen, J. K.; Jacobsen, K. E.; Stauning, P.; Henriksen, S.

    1983-12-01

    An HF system for studies of very high latitude ionospheric irregularities was described. Radio aurora from field-aligned E-region irregularities of the Slant E Condition type were discussed. The complete system combines an ionosonde, a 12 MHz pulse radar and a 12 MHz bistatic CW Doppler-range set-up. The two latter units use alternately a 360 deg rotating Yagi antenna. High precision oscillators secure the frequency stability of the Doppler system in which the received signal is mixed down to a center frequency of 500 Hz. The Doppler shift range is max + or - 500 Hz. The received signal is recorded in analog form on magnetic tape and may be monitored visually and audibly. Echo range of the CW Doppler signal is obtained by a 150 Hz amplitude modulation of the transmitted signal and phase comparison with the backscattered signal.

  7. Developments in HF equipment and systems mobile and portable terminals

    NASA Astrophysics Data System (ADS)

    Wilson, Q. C.

    1986-03-01

    Before the advent of satellite platforms, sophisticated high frequency (HF) propagation and system research promised improved capability during disturbed ionospheric propagation conditions. However, satellite relays captured the imaginations and pocketbooks of the communications community in the mid-1960s. Consequently, extant HF systems aged while satellite systems were implemented. During peacetime, satellite systems transmit quality low data rate communications and navigation aids to mobile users, but there is now renewed interest in the low cost and survivability attributes of HF radio. At this time, when old HF prime systems need replacement for logistical reasons, the need for low cost communications that can survive jamming, nuclear effects, and space warfare is not satisfied. The HF renaissance is the response to this challenge. Logistical replacement procurements that provide new capabilities are redressing the attrition of vacuum-tube radio equipment over the last decade. Procuring organizations typically compile specifications comprising state-of-the-art and new capabilities offered by competing vendors. Integrated circuits, which include microprocessors, synthesizer ele ments, and other evolving components, have led to new circuit architectures. The first of the following three sections describes: Receivers; Transceivers and Antenna Couplers; Antenna Kits; and Audio Channel Peripherals.

  8. HF acid blends based on formation conditions eliminate precipitation problems

    SciTech Connect

    Gdanski, R.; Shuchart, C.

    1997-03-01

    Formulating HCl-HF acid blends based on the mineralogy and temperature of a formation can increase the success of hydrofluoric acid (HF) treatments. Sodium and potassium in the structures of formation minerals can cause precipitation and matrix plugging problems during acidizing. Slight modifications of the acid blend used in the treatment can help eliminate fluosilicate precipitation. Researchers recently conducted tests to determine how acid blends react in different formations under varying temperatures. The results of the tests indicate that the minimum HCl:HF ratio in an acid blend is 6-to-1, and the optimum ratio is 9-to-1. Regular mud acid (12% HCl-3% HF) has been used successfully for years to enhance production in sandstone formations. By the 1980s, operators began to vary the concentration of HF and HCl acids to solve excessive sanding problems in sandstone. The paper discusses treatment problems, formation characteristics, alumino-silicate scaling, research results, brine compatibility, optimum treatment, and acid volume guidelines.

  9. Effect of HF leaching on 14C dates of pottery

    NASA Astrophysics Data System (ADS)

    Goslar, Tomasz; Kozłowski, Janusz; Szmyt, Marzena; Czernik, Justyna

    2013-01-01

    This paper presents the experiments with 14C dating of two potsherds, which contained carbon dispersed rather homogeneously in their clay fabric. After AAA treatment, the potsherds still appeared to be contaminated with young carbon, presumably connected with humic acids. To make removal of humic acids more effective, we treated the sherds with HF acid of different concentration. The 14C results obtained demonstrate that HF treatment indeed helps to remove humic contaminants, but it also mobilizes carbon bound to raw clay, which may make 14C dates too old. We conclude therefore, that using a simple combination of HF and AAA treatment seems insufficient in reliable 14C dating of carbon homogeneously dispersed in the volume of potsherds.

  10. Centrifugal stretching along the ground state band of Hf168

    NASA Astrophysics Data System (ADS)

    Costin, A.; Reese, M.; Ai, H.; Casten, R. F.; Dusling, K.; Fitzpatrick, C. R.; Gürdal, G.; Heinz, A.; McCutchan, E. A.; Meyer, D. A.; Möller, O.; Petkov, P.; Pietralla, N.; Qian, J.; Rainovski, G.; Werner, V.

    2009-02-01

    The lifetimes of the Jπ=4+, 6+, 8+, and 10+ levels along the ground state band in Hf168 were measured by means of the recoil distance Doppler shift (RDDS) method using the New Yale Plunger Device (NYPD) and the SPEEDY detection array at Wright Nuclear Structure Laboratory of Yale University. Excited states in Hf168 were populated using the Sn124(Ti48,4n) fusion evaporation reaction. The new lifetime values are sufficiently precise to clearly prove the increase of quadrupole deformation as a function of angular momentum in the deformed nucleus Hf168. The data agree with the predictions from the geometrical confined β-soft (CBS) rotor model that involves centrifugal stretching in a soft potential.

  11. MIMO communications within the HF band using compact antenna arrays

    NASA Astrophysics Data System (ADS)

    Gunashekar, S. D.; Warrington, E. M.; Feeney, S. M.; Salous, S.; Abbasi, N. M.

    2010-12-01

    Measurements have been made over a 255 km radio path between Durham and Leicester in the UK in order to investigate the potential applicability of multiple input multiple output (MIMO) techniques to communications within the HF band. This paper describes the results from experiments in which compact heterogeneous antenna arrays have been employed. The results of these experiments indicate that traditional spaced HF antenna arrays can be replaced by compact, active, heterogeneous arrays in order to achieve the required levels of decorrelation between the various antenna elements. An example case study is also presented which highlights the importance of the variable nature of the ionosphere in the context of HF-MIMO radio links.

  12. Feature Modeling of HfO2 Atomic Layer Deposition Using HfCl4/H2O

    NASA Astrophysics Data System (ADS)

    Stout, Phillip J.; Adams, Vance; Ventzek, Peter L. G.

    2003-03-01

    A Monte Carlo based feature scale model (Papaya) has been applied to atomic layer deposition (ALD) of HfO2 using HfCl_4/H_20. The model includes physical effects of transport to surface, specular and diffusive reflection within feature, adsorption, surface diffusion, deposition and etching. Discussed will be the 3D feature modeling of HfO2 deposition in assorted features (vias and trenches). The effect of feature aspect ratios, pulse times, cycle number, and temperature on film thickness, feature coverage, and film Cl fraction (surface/bulk) will be discussed. Differences between HfO2 ALD on blanket wafers and in features will be highlighted. For instance, the minimum pulse times sufficient for surface reaction saturation on blanket wafers needs to be increased when depositing on features. Also, HCl products created during the HfCl4 and H_20 pulses are more likely to react within a feature than at the field, reducing OH coverage within the feature (vs blanket wafer) thus limiting the maximum coverage attainable for a pulse over a feature.

  13. Podocyte hypertrophy, "adaptation," and "decompensation" associated with glomerular enlargement and glomerulosclerosis in the aging rat: prevention by calorie restriction.

    PubMed

    Wiggins, Jocelyn E; Goyal, Meera; Sanden, Silja K; Wharram, Bryan L; Shedden, Kerby A; Misek, David E; Kuick, Rork D; Wiggins, Roger C

    2005-10-01

    Whether podocyte depletion could cause the glomerulosclerosis of aging in Fischer 344 rats at ages 2, 6, 17, and 24 mo was evaluated. Ad libitum-fed rats developed proteinuria and glomerulosclerosis by 24 mo, whereas calorie-restricted rats did not. No evidence of age-associated progressive linear loss of podocytes from glomeruli was found. Rather, ad libitum-fed rats developed glomerular enlargement over time. To accommodate the increased glomerular volume, podocytes principally underwent hypertrophy, whereas other glomerular cells underwent hyperplasia. Stages of hypertrophy through which podocytes pass en route to podocyte loss and glomerulosclerosis were identified: Stage 1, normal podocyte; stage 2, nonstressed podocyte hypertrophy; stage 3, "adaptive" podocyte hypertrophy manifest by changes in synthesis of structural components (e.g., desmin) but maintenance of normal function; stage 4, "decompensated" podocyte hypertrophy relative to total glomerular volume manifest by reduced production of key machinery necessary for normal podocyte function (e.g., Wilms' tumor 1 protein [WT1], transcription factor pod1, nephrin, glomerular epithelial protein 1, podocalyxin, vascular endothelial growth factor, and alpha5 type IV collagen) and associated with widened foot processes and decreased filter efficiency (proteinuria); and stage 5, podocyte numbers decrease in association with focal segmental glomerulosclerosis. In contrast, in calorie-restricted rats, glomerular enlargement was minor, significant podocyte hypertrophy did not occur, podocyte machinery was unchanged, there was no proteinuria, and glomerulosclerosis did not develop. Glomerular enlargement therefore was associated with podocyte hypertrophy rather than hyperplasia. Hypertrophy above a certain threshold was associated with podocyte stress and then failure, culminating in reduced podocyte numbers in sclerotic glomeruli. This process could be prevented by calorie restriction.

  14. Ascites’ neutrophil function is significantly impaired in patients with decompensated cirrhosis but can be restored by autologous plasma incubation

    PubMed Central

    Engelmann, Cornelius; Becker, Christina; Boldt, Andreas; Herta, Toni; Boehlig, Albrecht; Splith, Katrin; Schmelzle, Moritz; Mueller, Niklas; Krohn, Sandra; Tautenhahn, Hans-Michael; Bartels, Michael; Sack, Ulrich; Berg, Thomas

    2016-01-01

    Systemic immune cell dysfunction is a typical feature of liver diseases and increases the risk of bacterial infection, especially spontaneous bacterial peritonitis. We evaluated functional properties of neutrophil granulocytes in blood and ascites of patients both with and without decompensated cirrhosis. We collected blood and ascites samples from 63 patients with cirrhosis and eight without cirrhosis. Phagocytosis activity (PA) and oxidative burst activity (OBA) were evaluated after ex vivo stimulation with E. coli, while fluorescence signals were measured by flow cytometry. Ascites’ neutrophil function tests were repeated after incubation with autologous plasma. Ascites’ neutrophils showed an impaired PA and OBA (median blood PA 98.1% (86.8–99.8) vs. ascites’ PA 50.5% (0.4–97.3), p < 0.0001; median blood OBA 98.7% (27.5–100) vs. ascites’ OBA 27.5% (0.3–96.7), p < 0.0001). Patients with non-cirrhotic ascites showed higher PA but equally suppressed OBA. Ascites’ neutrophil function could be partially restored after incubation with autologous plasma (median increase PA: 22.5% (−49.7 – +93.2), p = 0.002; OBA: 22.8% (−10.4 – +48.8), p = 0.002). Ascites’ neutrophils of patients with cirrhosis are functionally impaired, but could be partially restored after incubation with plasma. Further investigations are needed to identify the factors in ascites that are associated with neutrophils’ function. PMID:27917877

  15. Importance of the Lu-Hf isotopic system in studies of planetary chronology and chemical evolution

    USGS Publications Warehouse

    Patchett, P.J.

    1983-01-01

    The 176Lu-176Hf isotope method and its applications in earth sciences are discussed. Greater fractionation of Lu/Hf than Sm/Nd in planetary magmatic processes makes 176Hf 177Hf a powerful geochemical tracer. In general, proportional variations of 176Hf 177Hf exceed those of 143Nd l44Nd by factors of 1.5-3 in terrestrial and lunar materials. Lu-Hf studies therefore have a major contribution to make in understanding of terrestrial and other planetary evolution through time, and this is the principal importance of Lu-Hf. New data on basalts from oceanic islands show unequivocally that whereas considerable divergences occur in 176Hf 177Hf- 87Sr 86Sr and 143Nd l44Nd- 87Sr 86Sr diagrams, 176Hf 177Hf and 143Nd 144Nd display a single, linear isotopic variation in the suboceanic mantle. These discordant 87Sr 86Sr relationships may allow, with the acquisition of further Hf-Nd-Sr isotopic data, a distinction between processes such as mantle metasomatism, influence of seawater-altered material in the magma source, or recycling of sediments into the mantle. In order to evaluate the Hf-Nd isotopic correlation in terms of mantle fractionation history, there is a need for measurements of Hf distribution coefficients between silicate minerals and liquids, and specifically for a knowledge of Hf behavior in relation to rareearth elements. For studying ancient terrestrial Hf isotopic variations, the best quality Hf isotope data are obtained from granitoid rocks or zircons. New data show that very U-Pb discordant zircons may have upwardly-biased 176Hf 177Hf, but that at least concordant to slightly discordant zircons appear to be reliable carriers of initial 176Hf 177Hf. Until the controls on addition of radiogenic Hf to zircon are understood, combined zircon-whole rock studies are recommended. Lu-Hf has been demonstrated as a viable tool for dating of ancient terrestrial and extraterrestrial samples, but because it offers little advantage over existing methods, is unlikely to find

  16. Hf--Co--B alloys as permanent magnet materials

    DOEpatents

    McGuire, Michael Alan; Rios, Orlando; Ghimire, Nirmal Jeevi

    2017-01-24

    An alloy composition is composed essentially of Hf.sub.2-XZr.sub.XCo.sub.11B.sub.Y, wherein 0Hf.sub.2-XZr.sub.XCo.sub.11B.sub.Y, wherein 0.ltoreq.X<2 and 0

  17. First HF radar measurements of summer mesopause echoes at SURA

    NASA Astrophysics Data System (ADS)

    Karashtin, A. N.; Shlyugaev, Y. V.; Abramov, V. I.; Belov, I. F.; Berezin, I. V.; Bychkov, V. V.; Eryshev, E. B.; Komrakov, G. P.

    1997-07-01

    HF sounding of the mesosphere was first carried out at SURA in summer 1994 at frequencies in the range 8-9 MHz using one of the sub-arrays of the SURA heating facility. The observations had a range resolution of 3 km. Almost all measurements indicated the presence of strong radar returns from altitudes between 83 and 90 km with features very similar to VHF measurements of mesopause summer echoes at mid-latitudes and polar mesopause summer echoes. In contrast to VHF observations, HF mesopause echoes are almost always present.

  18. Field operations with cesium clocks in HF navigation systems

    NASA Technical Reports Server (NTRS)

    Christy, E. H.; Clayton, D. A.

    1982-01-01

    Networks of HF phase comparison marine navigation stations employing cesium clocks are discussed. The largest permanent network is in the Gulf of Mexico where some fourteen base stations are continuously active and others are activated as needed. These HF phase comparison systems, which operate on a single transmission path, require a clock on the mobile unit as well. Inventory consists of upwards of 70 clocks from two different manufacturers. The maintenance of this network as an operating system requires a coordinated effort involving clock preparation, clock environment control, station performance monitoring and field service.

  19. Wideband model of man-made HF noise and interference

    NASA Astrophysics Data System (ADS)

    Lemmon, John J.

    1997-03-01

    A mathematical model of the waveform generated by man-made high frequency (HF) noise and interference is presented and discussed. The model is based on wideband (800 kHz) recordings of the noise and interference at various frequencies in the HF band. Representative examples of first- and higher-order statistics of the measured waveforms are described, including probability distributions of the envelope and phase of the noise and interference in the time and frequency domains, power spectra, autocorrelation functions, and level crossing distributions. The statistics of waveforms generated by the model closely resemble the statistics of the measured data.

  20. HF-Induced Airglow at Magnetic Zenith: Theoretical Considerations

    DTIC Science & Technology

    2007-11-02

    7.8 MHz. Significantly, green -to-red ratios fgr >0.3 are often ob- For a heater ERP Po= 150 MW and distance R=250 kin, served. Gustavsson et al...and 145.15’W) show that the HF-induced airglow maximizes 557.7nm ( green line) during HF modification experiments during injections toward magnetic...1989; Pedersen and injected frequency f0. Here, Oc=arcsin( fsinx), f, is Carlson, 2001; Gustavsson et al., 2001, 2002; Kosch et al., the electron

  1. New process additive reduces HF cloud-forming potential

    SciTech Connect

    Sheckler, J.C.; Hammershaimb, H.U. ); Ross, L.J. ); Comey, K.R. III )

    1994-08-22

    The Texaco-UOP HF additive technology has demonstrated significant aerosol reduction in both small-scale and large-scale releases. The pilot plant testing did not indicate any adverse impact on the alkylation reaction, as was confirmed in a short trial at Texaco Refining and Marketing Inc.'s El Dorado, Kan., refinery in 1992. Equipment to enable continuous addition of the additive was installed in the second quarter of 1994 at the refinery. The paper discusses HF alkylation, mitigation technology, additive development, aerosol reduction, and testing on pilot scale and large scale.

  2. European coordination for coastal HF radar data in EMODnet Physics

    NASA Astrophysics Data System (ADS)

    Mader, Julien; Novellino, Antonio; Gorringe, Patrick; Griffa, Annalisa; Schulz-Stellenfleth, Johannes; Montero, Pedro; Montovani, Carlo; Ayensa, Garbi; Vila, Begoña; Rubio, Anna; Sagarminaga, Yolanda

    2015-04-01

    Historically, joint effort has been put on observing open ocean, organizing, homogenizing, sharing and reinforcing the impact of the acquired information based on one technology: ARGO with profilers Argo floats, EuroSites, ESONET-NoE, FixO3 for deep water platforms, Ferrybox for stations in ships of opportunities, and GROOM for the more recent gliders. This kind of networking creates synergies and makes easier the implementation of this source of data in the European Data exchange services like EMODnet, ROOSs portals, or any applied services in the Blue economy. One main targeted improvement in the second phase of EMODnet projects is the assembling of data along coastline. In that sense, further coordination is recommended between platform operators around a specific technology in order to make easier the implementation of the data in the platforms (4th EuroGOOS DATAMEQ WG). HF radar is today recognized internationally as a cost-effective solution to provide high spatial and temporal resolution current maps (depending on the instrument operation frequency, covering from a few kilometres offshore up to 200 km) that are needed for many applications for issues related to ocean surface drift or sea state characterization. Significant heterogeneity still exists in Europe concerning technological configurations, data processing, quality standards and data availability. This makes more difficult the development of a significant network for achieving the needed accessibility to HF Radar data for a pan European use. EuroGOOS took the initiative to lead and coordinate activities within the various observation platforms by establishing a number of Ocean Observing Task Teams such as HF-Radars. The purpose is to coordinate and join the technological, scientific and operational HF radar communities at European level. The goal of the group is on the harmonization of systems requirements, systems design, data quality, improvement and proof of the readiness and standardization of

  3. Ca + HF - The anatomy of a chemical insertion reaction

    NASA Technical Reports Server (NTRS)

    Jaffe, R. L.; Pattengill, M. D.; Mascarello, F. G.; Zare, R. N.

    1987-01-01

    A comprehensive first-principles theoretical investigation of the gas phase reaction Ca + HF - CaF + H is reported. Ab initio potential energy calculations are first discussed, along with characteristics of the computed potential energy surface. Next, the fitting of the computed potential energy points to a suitable analytical functional form is described, and maps of the fitted potential surface are displayed. The methodology and results of a classical trajectory calculation utilizing the fitted potential surface are presented. Finally, the significance of the trajectory study results is discussed, and generalizations concerning dynamical aspects of Ca + HF scattering are drawn.

  4. A routine high-precision method for Lu-Hf isotope geochemistry and chronology

    USGS Publications Warehouse

    Patchett, P.J.; Tatsumoto, M.

    1981-01-01

    A method for chemical separation of Lu and Hf from rock, meteorite and mineral samples is described, together with a much improved mass spectrometric running technique for Hf. This allows (i) geo- and cosmochronology using the176Lu???176Hf+??- decay scheme, and (ii) geochemical studies of planetary processes in the earth and moon. Chemical yields for the three-stage ion-exchange column procedure average 90% for Hf. Chemical blanks are <0.2 ng for Lu and Hf. From 1 ??g of Hf, a total ion current of 0.5??10-11 Ampere can be maintained for 3-5 h, yielding 0.01-0.03% precision on the ratio176Hf/177Hf. Normalisation to179Hf/177Hf=0.7325 is used. Extensive results for the Johnson Matthey Hf standard JMC 475 are presented, and this sample is urged as an international mass spectrometric standard; suitable aliquots, prepared from a single batch of JMC 475, are available from Denver. Lu-Hf analyses of the standard rocks BCR-1 and JB-1 are given. The potential of the Lu-Hf method in isotope geochemistry is assessed. ?? 1980 Springer-Verlag.

  5. Treat chronic hepatitis C virus infection in decompensated cirrhosis - pre- or post-liver transplantation? the ironic conundrum in the era of effective and well-tolerated therapy.

    PubMed

    Bunchorntavakul, C; Reddy, K Rajender

    2016-06-01

    The management of hepatitis C virus (HCV) infection in patients with decompensated cirrhosis has evolved dramatically over the past few years mainly due to the availability of all-oral antiviral regimens. The currently approved all-oral direct-acting antivirals (DAA) containing sofosbuvir, ledipasvir, daclatasvir and ribavirin, in various combinations, have shown to be safe and effective in patients with decompensated cirrhosis with sustained virological response (SVR) rates nearly comparable to those with well-compensated liver disease. Unique issues yet remain such as the challenges with renal insufficiency, tolerability of ribavirin and risk of further hepatic decompensation with a protease inhibitor-based regimen. While most patients who achieve SVR have demonstrated improvement in hepatic synthetic function over the short course of follow, the long-term beneficial effects are unknown. Further, the baseline predictors of improvement in hepatic function have not been well delineated and thus have left us in a quandary as to what we might expect with successful therapy and thus we are at a loss to well educate our patients. The major concern, in potential liver transplant candidates, is of unintended 'harm' by achieving SVR but without improvement in hepatic function to an extent where the patients might function well. As HCV therapies are as effective in liver transplant recipients, there is a growing sentiment in some of the transplant quarters that those with decompensated liver disease and awaiting liver transplant be treated for HCV after liver transplant. This strategy would thus eliminate any concern of leaving a patient in 'no person's' land by treating HCV successfully pretransplant but not to the point of functional normalcy, while also would maintain the risk of HCC. Yet a contrarian view would be that not all patients have access to liver transplantation (LT), cannot bear the cost, have comorbidities or contraindications to LT. While the debate

  6. Comparative study of atomic-layer-deposited HfO2/Al2O3, Hf0.8Al0.2Ox and Hf0.5Al0.5Ox on N-GaAs

    NASA Astrophysics Data System (ADS)

    Yu, Xinjiang; Lv, Hongliang; Zhang, Yuming; Zhang, Yimen; Qin, Zaiyang

    2016-11-01

    Interfacial properties of n-GaAs metal-oxide-semiconductor (MOSCAPs) with the gate dielectrics of HfO2/Al2O3, Hf0.8Al0.2Ox and Hf0.5Al0.5Ox are investigated. The results reveal that Hf0.5Al0.5Ox has larger permittivity and lower interface trap density than that of HfO2/Al2O3. In order to explain the result from the physical perspective, the XPS tests of all three samples are performed. It is found that the main reason to form interface trap of three samples treated with 500 °C post-deposition annealing, is attributed to the interfacial component of Ga2O3 and The Hf0.5Al0.5Ox dielectric is beneficial to reducing the formation of Ga2O3.

  7. Effectiveness of Haemodiafiltration with Heat Sterilized High-Flux Polyphenylene HF Dialyzer in Reducing Free Light Chains in Patients with Myeloma Cast Nephropathy

    PubMed Central

    2015-01-01

    Introduction In cases of myeloma cast nephropathy in need of haemodialysis (HD), reduction of free light chains using HD with High-Cut-Off filters (HCO-HD), in combination with chemotherapy, may be associated with better renal recovery. The aim of the present study is to evaluate the effectiveness of haemodiafiltration (HDF) in reducing free light chain levels using a less expensive heat sterilized high-flux polyphenylene HF dialyzer (HF-HDF). Methods In a single-centre prospective cohort study, 327 dialysis sessions were performed using a 2.2 m2 heat sterilized high-flux polyphenylene HF dialyzer (Phylther HF22SD), a small (1.1m2) or large (2.1 m2) high-cut-off (HCO) dialyzer (HCOS and HCOL) in a cohort of 16 patients presenting with dialysis-dependent acute cast nephropathy and elevated free light chains (10 kappa, 6 lambda). The outcomes of the study were the mean reduction ratio (RR) of kappa and lambda, the proportion of treatments with an RR of at least 0.65, albumin loss and the description of patient outcomes. Statistical analysis was performed using linear and logistic regression through generalized estimating equation analysis so as to take into account repeated observation within subjects and adjust for session duration. Results There were no significant differences in the estimated marginal mean of kappa RR, which were respectively 0.67, 0.69 and 0.70 with HCOL-HD, HCOS-HDF and HF-HDF (P = 0.950). The estimated marginal mean of the proportions of treatments with a kappa RR ≥0.65 were 68%, 63% and 71% with HCOL-HD, HCOS-HDF and HF-HDF, respectively (P = 0.913). The estimated marginal mean of lambda RR were higher with HCOL-HDF (0.78), compared to HCOL-HD and HF-HDF (0.62, and 0.61 respectively). The estimated marginal mean proportion of treatments with a lambda RR ≥0.65 were higher with HCOL-HDF (81%), compared to 57% in HF-HDF (P = 0.042). The median albumin loss were 7, 21 and 63 g/session with HF-HDF, HCOL-HD and HCOL-HDF respectively (P = 0

  8. The Status of Rotational Nonequilibrium in HF Chemical Lasers

    DTIC Science & Technology

    1986-05-01

    8217 -" II. EVIDENCE FOR ROTATIONAL NONEQUILIBRIU IN HF LASERS Since 1967 there has been a mounting body of evidence that the rotational populations within a...Physique C9 41, 17 (1980). 100. L. H. Sentman and W. Rushmore , ATAA 81-4272 19j 1323 (1981). 101. L. H. Sentman, W. 0. Mosebach, and P. Renzoni, A

  9. First 100 ms of HF modification at Tromso, Norway

    NASA Astrophysics Data System (ADS)

    Djuth, F. T.; Isham, B.; Rietveld, M. T.; Hagfors, T.; La Hoz, C.

    Experiments were performed with the high-power high-frequency HF facility at Troms o Norway to test theoretical predictions for the excitation of ion and Langmuir oscillations in the ionosphere The principal diagnostic of wave-plasma interactions was the VHF radar at the European Incoherent Scatter EISCAT facility High resolution radar techniques were used to monitor the temporal development of the ion and Langmuir oscillations HF pulses 100 ms in duration were periodically transmitted into a smooth background F region plasma Measurements of the radar backscatter spectra show that all key spectral features predicted by strong Langmuir turbulence SLT theory modified Zakharov model are simultaneously present in the plasma and that their evolution is in agreement with theoretical expectations However several new features have been observed that cannot be anticipated by current theory because of limitations in the electric field strength within the simulations The experimental results reinforce the notion that new theoretical developments are needed to accommodate the large HF electric fields produced at Troms o and HAARP Gakona Alaska and to treat the electron acceleration process in a self-consistent fashion The F region response to two HF effective radiated power levels sim 58 MW and sim 125 MW was investigated at Troms o These ERP values include absorptive losses resulting from the sunlit D region In general the results at 58 MW ERP and 125 MW ERP are consistent with many of the SLT

  10. ORIGIN OF EXCESS {sup 176}Hf IN METEORITES

    SciTech Connect

    Thrane, Kristine; Connelly, James N.; Bizzarro, Martin; Meyer, Bradley S.; The, Lih-Sin

    2010-07-10

    After considerable controversy regarding the {sup 176}Lu decay constant ({lambda}{sup 176}Lu), there is now widespread agreement that (1.867 {+-} 0.008) x 10{sup -11} yr{sup -1} as confirmed by various terrestrial objects and a 4557 Myr meteorite is correct. This leaves the {sup 176}Hf excesses that are correlated with Lu/Hf elemental ratios in meteorites older than {approx}4.56 Ga meteorites unresolved. We attribute {sup 176}Hf excess in older meteorites to an accelerated decay of {sup 176}Lu caused by excitation of the long-lived {sup 176}Lu ground state to a short-lived {sup 176m}Lu isomer. The energy needed to cause this transition is ascribed to a post-crystallization spray of cosmic rays accelerated by nearby supernova(e) that occurred after 4564.5 Ma. The majority of these cosmic rays are estimated to penetrate accreted material down to 10-20 m, whereas a small fraction penetrate as deep as 100-200 m, predicting decreased excesses of {sup 176}Hf with depth of burial at the time of the irradiation event.

  11. Noble gas encapsulation: clathrate hydrates and their HF doped analogues.

    PubMed

    Mondal, Sukanta; Chattaraj, Pratim Kumar

    2014-09-07

    The significance of clathrate hydrates lies in their ability to encapsulate a vast range of inert gases. Although the natural abundance of a few noble gases (Kr and Xe) is poor their hydrates are generally abundant. It has already been reported that HF doping enhances the stability of hydrogen hydrates and methane hydrates, which prompted us to perform a model study on helium, neon and argon hydrates with their HF doped analogues. For this purpose 5(12), 5(12)6(8) and their HF doped analogues are taken as the model clathrate hydrates, which are among the building blocks of sI, sII and sH types of clathrate hydrate crystals. We use the dispersion corrected and gradient corrected hybrid density functional theory for the calculation of thermodynamic parameters as well as conceptual density functional theory based reactivity descriptors. The method of the ab initio molecular dynamics (AIMD) simulation is used through atom centered density matrix propagation (ADMP) techniques to envisage the structural behaviour of different noble gas hydrates on a 500 fs timescale. Electron density analysis is carried out to understand the nature of Ng-OH2, Ng-FH and Ng-Ng interactions. The current results noticeably demonstrate that the noble gas (He, Ne, and Ar) encapsulation ability of 5(12), 5(12)6(8) and their HF doped analogues is thermodynamically favourable.

  12. The multilayer Fe/Hf studied with slow positron beam

    NASA Astrophysics Data System (ADS)

    Murashige, Y.; Tashiro, M.; Nakajyo, T.; Koizumi, T.; Kanazawa, I.; Komori, F.; Ito, Y.

    1997-04-01

    The positron annihilation parameter versus the incident positron energy is measured in the thin Fe films and the Fe/Hf bilayer on silica substrate, by means of the variable energetic slow-positron beam technique. We have analyzed the change in open-volume spaces and vacancy-type defects among the Fe microcrystals in these thin films with the deposition temperature.

  13. Spectral output from a premixed chain reaction cw HF laser

    SciTech Connect

    Stanton, A.C.; Bien, F.

    1980-07-01

    Spectral measurements of the output from a purely chemical chain reaction cw HF laser are reported. The laser is a subsonic H/sub 2/-F/sub 2/ flame, with supersonic premixing and spatially uniform initiation by a stationary normal shock. Initial chemical production of fluorine atoms is by the bimolecular reaction of F/sub 2/ with NO. Spectral measurements of the laser output near the initiating shock indicate lasing transitions in the P branches of the v=3 ..-->.. v=2, v=2 ..-->.. v=1, and v=1 ..-->.. v=0 HF bands. Further downstream, the upper vibrational levels are strongly deactivated, and lasing occurs only in the v=1 ..-->.. v=0 band. Laser emission in the v=2 ..-->.. v=1 band reappears at reduced NO flow rates, suggesting efficient deactivation of HF (v) by NO, possibly through multiquantum V-V exchange. An approximate rate of 5 x 10/sup -13plus-or-minus0.5/ cm/sup 3//sec for deactivation of HF (v=2) by NO is inferred.

  14. Composition effects on mechanical properties of HfC-strengthened molybdenum alloys

    NASA Technical Reports Server (NTRS)

    Witzke, W. R.

    1976-01-01

    The mechanical properties of swaged rod thermomechanically processed from arc-melted Mo-2Re-Hf-C alloys containing as much as 0.9 mol pct HfC have been evaluated. The low temperature ductilities of these alloys were not influenced by the amount of HfC present but by the amount of Hf in excess of stoichiometry. Maximum ductility occurred at 0.2 to 0.3 at. pct excess Hf. At 0.3 to 0.5 mol pct HfC, alloy strength varied directly with the Mo content of extracted carbide particles, both decreasing as the amount of excess Hf increased. Additions of 2 at. pct Re had little effect on strength or ductility. Tensile and creep strengths of Mo-2Re-0.7Hf-0.5C alloy equaled or exceeded those of other high strength Mo alloys.

  15. Freestanding HfO2 grating fabricated by fast atom beam etching

    NASA Astrophysics Data System (ADS)

    Wang, Yongjin; Wu, Tong; Kanamori, Yoshiaki; Hane, Kazuhiro

    2011-04-01

    We report here the fabrication of freestanding HfO2 grating by combining fast atom beam etching (FAB) of HfO2 film with dry etching of silicon substrate. HfO2 film is deposited onto silicon substrate by electron beam evaporator. The grating patterns are then defined by electron beam lithography and transferred to HfO2 film by FAB etching. The silicon substrate beneath the HfO2 grating region is removed to make the HfO2 grating suspend in space. Period- and polarization-dependent optical responses of fabricated HfO2 gratings are experimentally characterized in the reflectance measurements. The simple process is feasible for fabricating freestanding HfO2 grating that is a potential candidate for single layer dielectric reflector. PACS: 73.40.Ty; 42.70.Qs; 81.65.Cf.

  16. Acute Kidney Injury in Patients with Cirrhosis

    PubMed Central

    Russ, Kirk B.; Stevens, Todd M; Singal, Ashwani K.

    2015-01-01

    Acute kidney injury (AKI) occurs commonly in patients with advanced cirrhosis and negatively impacts pre- and post-transplant outcomes. Physiologic changes that occur in patients with decompensated cirrhosis with ascites, place these patients at high risk of AKI. The most common causes of AKI in cirrhosis include prerenal injury, acute tubular necrosis (ATN), and the hepatorenal syndrome (HRS), accounting for more than 80% of AKI in this population. Distinguishing between these causes is particularly important for prognostication and treatment. Treatment of Type 1 HRS with vasoconstrictors and albumin improves short term survival and renal function in some patients while awaiting liver transplantation. Patients with HRS who fail to respond to medical therapy or those with severe renal failure of other etiology may require renal replacement therapy. Simultaneous liver kidney transplant (SLK) is needed in many of these patients to improve their post-transplant outcomes. However, the criteria to select patients who would benefit from SLK transplantation are based on consensus and lack strong evidence to support them. In this regard, novel serum and/or urinary biomarkers such as neutrophil gelatinase-associated lipocalin, interleukins-6 and 18, kidney injury molecule-1, fatty acid binding protein, and endothelin-1 are emerging with a potential for accurately differentiating common causes of AKI. Prospective studies are needed on the use of these biomarkers to predict accurately renal function recovery after liver transplantation alone in order to optimize personalized use of SLK. PMID:26623266

  17. [Severe acute liver failure: a case study].

    PubMed

    Moreno Arroyo, M Carmen; Puig Llobet, Montserrat; Cuervo Lavado, Luis

    2012-01-01

    Fulminant hepatic failure (FHF), also known as fulminant hepatitis, is a rare and extremely serious condition with a high mortality rate. Its rapid evolution and complexity in managing the treatment, creates the need to provide some immediate care by a team that specialises in intensive care. This acute decompensation is usually associated with other disorders, such as coagulopathy and hepatic encephalopathy, being responsible for major complications that can lead to organ failure. In our region the most common origin is unknown, followed by acute infection with hepatitis B. The treatment of this syndrome is based on the general measures applicable to any critically ill patient: treat the cause and early detection of extrahepatic complications, urgent liver transplantation being one of the alternatives with a better prognosis. This article presents a case report describing the monitoring of an Irish woman of 20 years who was transferred from a hospital in Ibiza to a hospital in Barcelona, with a suspected diagnosis of FHF. Following the conceptual model of Virginia Henderson, the collaborative problems and nursing diagnoses are described, presenting a care plan according to NANDA (North American Nursing Association), NIC (Nursing Intervention Classification), NOC (Nursing Outcomes Classification). This case helps to establish an individualised care plan that provides guidance to nurse professionals in critical patient care by increasing the knowledge of FHF.

  18. Acute Bronchitis

    MedlinePlus

    ... can also cause acute bronchitis. To diagnose acute bronchitis, your health care provider will ask about your symptoms and listen to your breathing. You may also have other tests. Treatments include rest, fluids, and aspirin (for adults) or ...

  19. Effects of Zr impurity on microscopic behavior of Hf metal

    NASA Astrophysics Data System (ADS)

    Dey, S. K.; Dey, C. C.; Saha, S.

    2016-08-01

    Hf metal with ∼ 3 wt% Zr impurity has been reinvestigated by perturbed angular correlation (PAC) spectroscopy using a LaBr3(Ce)-BaF2 detector set up to understand the microscopic behavior of this metal with temperature. From present measurements, five quadrupole interaction frequencies have been found at room temperature where both pure hcp fraction (∼33%) with 12 nearest neighbor Hf surrounding the probe 181Hf atom and the probe-impurity fraction (∼33%) corresponding to 11 nearest neighbor Hf plus one dissimilar Zr atom are clearly distinguished. At room temperature, the results for quadrupole frequency and asymmetry parameter are found to be ωQ=51.6(4) Mrad/s, η=0.20(4) for the impurity fraction and ωQ=46.8(2) Mrad/s, η=0 for the pure fraction with values of frequency distribution width δ=0 for both components. At 77 K, only 1 NN Zr impurity (∼93%) and pure hcp (∼7%) components have been found with a value of δ ∼ 10% for the impurity fraction. A drastic change in microstructural configuration of Hf metal is observed at 473 K where the impurity fraction increases to ∼ 50% and the pure hcp fraction reduces to ∼ 15% with abrupt changes in quadrupole frequencies for both components. The pure fraction then increases with temperature and enhances to ∼50% at 973 K. In the temperature range 473-973 K, quadrupole frequencies for both components are found to decrease slowly with temperature. Using the Arrhenius relation, binding energy (B) for the probe-impurity pair and the entropy of formation are measured from temperature dependent fractions of probe-impurity and pure hcp in the temperature range 473-773 K. The three other minor components found at different temperatures are attributed to crystalline defects.

  20. A first principles thermodynamic study of Si-HfO2 and Pt-HfO2 interfaces

    NASA Astrophysics Data System (ADS)

    Zhu, Hong; Ramprasad, Rampi

    2012-02-01

    Atomic-level control of dielectric-semiconductor and dielectric-metal interfaces has become critical in determining the properties of the emerging high-k oxide-based MOSFETs. Using Si-HfO2 and Pt-HfO2 as an example, we investigate the evolution of these interface structures and electronic properties as a function of processing conditions by combining density functional theory results and statistical thermodynamics. Firstly, using first principles thermodynamics (FPTs), we determine the phase diagrams of Si-HfO2 and Pt-HfO2 interfaces. The vibrational and configurational entropic contributions to the free energies of the condensed phases are explicitly included. We demonstrate that the predictions of the FPT approach are in quantitative agreement with experiments for the interfaces considered. Secondly, a parameter-free methodology to determine the work function shift (or effective work function, EWF) of metal when interfaced with oxide is developed. This strategy is combined with statistical thermodynamics to predict the most probable EWF at given processing condition. The favorable agreement between the computed and experimental EWFs under generally adopted conditions is indicative of the usefulness of such full first-principles property-processing relationship studies.

  1. Observation of Reliability of HfZrOX Gate Dielectric Devices with Different Zr/Hf Ratios

    NASA Astrophysics Data System (ADS)

    Liao, Jing-Chyi; Fang, Yean-Kuen; Tian Hou, Yong; Hsiung Tseng, Wei; Yang, Chih I.; Hsu, Peng Fu; Chao, Yuen Shun; Lin, Kang Cheng; Huang, Kuo Tai; Lee, Tzu Liang; Liang, Meng Sung

    2008-04-01

    The impact of the Zr/Hf ratio on the reliability of a HfZrOX gate dielectric has been investigated in detail. By a frequency-varied charge-pumping method, we found that the density of bulk traps is reduced with increasing Zr content. Also, a comparable Dit value observed by the rising/falling time-varied charge-pumping method suggests that Zr incorporation does not degrade the interface quality. Consequently, mobility increases with increasing Zr content in the HfZrOX dielectric and ˜25% mobility enhancement compared with that of HfO2 can be observed. However, the bulk trap density reduction reaches saturation at a higher Zr content. The improvement in positive-bias temperature instability (PBTI) was also demonstrated by both DC and pulse techniques. The smaller Vth shift in PBTI is attributed to the reduction of fast trapping and the generation of slow traps. Finally, a reduced gate-induced drain leakage current (GIDL) was also observed with increasing Zr content because of the reduction of trap-assisted tunneling in a high-k film.

  2. 40 CFR 180.1273 - Beauveria bassiana HF23; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Beauveria bassiana HF23; exemption... FOOD Exemptions From Tolerances § 180.1273 Beauveria bassiana HF23; exemption from the requirement of a tolerance. Residues of Beauveria bassiana HF23 are exempt from the requirement of a tolerance on all...

  3. Rifaximin has no effect on hemodynamics in decompensated cirrhosis: A randomized, double-blind, placebo-controlled trial.

    PubMed

    Kimer, Nina; Pedersen, Julie Steen; Busk, Troels Malte; Gluud, Lise Lotte; Hobolth, Lise; Krag, Aleksander; Møller, Søren; Bendtsen, Flemming

    2017-02-01

    Decompensated cirrhosis is characterized by disturbed systemic and splanchnic hemodynamics. Bacterial translocation from the gut is considered the key driver in this process. Intestinal decontamination with rifaximin may improve hemodynamics. This double-blind, randomized, controlled trial (clinicaltrials.gov, NCT01769040) investigates the effects of rifaximin on hemodynamics, renal function, and vasoactive hormones. We randomized 54 stable outpatients with cirrhosis and ascites to rifaximin 550 mg twice a day (n = 36) or placebo twice a day (n = 18). Forty-five patients were male, mean age 56 years (±8.4), average Child score 8.3 (±1.3), and Model for End-Stage Liver Disease score 11.7 (±3.9). Measurements of hepatic venous pressure gradient, cardiac output, and systemic vascular resistance were made at baseline and after 4 weeks. The glomerular filtration rate and plasma renin, noradrenaline, lipopolysaccharide binding protein, troponin T, and brain natriuretic peptide levels were measured. Rifaximin had no effect on hepatic venous pressure gradient, mean 16.8 ± 3.8 mm Hg at baseline versus 16.6 ± 5.3 mm Hg at follow-up, compared to the placebo, mean 16.4 ± 4 mm Hg at baseline versus 16.3 ± 4.4 mm Hg at follow-up, P = 0.94. No effect was found on cardiac output, mean 6.9 ± 1.7 L/min at baseline versus 6.9 ± 2.3 L/min at follow-up, compared to placebo, mean 6.6 ± 1.9 L/min at baseline compared to 6.5 ±2.1 L/min at follow-up, P = 0.66. No effects on the glomerular filtration rate, P = 0.14, or vasoactive hormones were found. Subgroup analyses on patients with increased lipopolysaccharide binding protein and systemic vascular resistance below the mean (1,011 dynes × s/cm(5) ) revealed no effect of rifaximin.

  4. Two-dimensional semiconductor HfSe{sub 2} and MoSe{sub 2}/HfSe{sub 2} van der Waals heterostructures by molecular beam epitaxy

    SciTech Connect

    Aretouli, K. E.; Tsipas, P.; Tsoutsou, D.; Marquez-Velasco, J.; Xenogiannopoulou, E.; Giamini, S. A.; Vassalou, E.; Kelaidis, N.; Dimoulas, A.

    2015-04-06

    Using molecular beam epitaxy, atomically thin 2D semiconductor HfSe{sub 2} and MoSe{sub 2}/HfSe{sub 2} van der Waals heterostructures are grown on AlN(0001)/Si(111) substrates. Details of the electronic band structure of HfSe{sub 2} are imaged by in-situ angle resolved photoelectron spectroscopy indicating a high quality epitaxial layer. High-resolution surface tunneling microscopy supported by first principles calculations provides evidence of an ordered Se adlayer, which may be responsible for a reduction of the measured workfunction of HfSe{sub 2} compared to theoretical predictions. The latter reduction minimizes the workfunction difference between the HfSe{sub 2} and MoSe{sub 2} layers resulting in a small valence band offset of only 0.13 eV at the MoSe{sub 2}/HfSe{sub 2} heterointerface and a weak type II band alignment.

  5. The relational dimension of care for maternity blues and its relation to decompensation of a psychiatric disorder during the intermediate postpartum period in Cameroon.

    PubMed

    Mboua, C P; Nkoum, B A; Abessouguié, S P

    2016-08-01

    In a setting such as Cameroon, where perinatal care offers few services for women with psychiatric problems during pregnancy, delivery, and the immediate postpartum period, the development of the relational dimension of care may help prevent severe psychiatric disorders . This study evaluates the role of the relational dimension of perinatal and early postpartum care (providing perinatal counseling and a space to speak) on women with blues on the intermediate-term outcomes of decompensation, in view of the importance of the emotional issues occurring in the perinatal period. Data collection used both diagnostic and clinical methods on a sample of 50 women from three hospitals in Cameroon who gave birth during the study period and agreed to participate. Of the 38 diagnosed with blues, 10 were available for observation during the intermediate post-partum: they were sorted into an experimental group that received perinatal counseling (n=5) and a control group that did not. The results suggest the importance to women with blues of a space for talking during the post-partum period. In particular, the quality of this counseling, in terms of the emotional responses of the nursing staff, determines the outcome of this management and can help to reduce the outset of depression and decompensation.

  6. [Organ damage and cardiorenal syndrome in acute heart failure].

    PubMed

    Casado Cerrada, Jesús; Pérez Calvo, Juan Ignacio

    2014-03-01

    Heart failure is a complex syndrome that affects almost all organs and systems of the body. Signs and symptoms of organ dysfunction, in particular kidney dysfunction, may be accentuated or become evident for the first time during acute decompensation of heart failure. Cardiorenal syndrome has been defined as the simultaneous dysfunction of both the heart and the kidney, regardless of which of the two organs may have suffered the initial damage and regardless also of their previous functional status. Research into the mechanisms regulating the complex relationship between the two organs is prompting the search for new biomarkers to help physicians detect renal damage in subclinical stages. Hence, a preventive approach to renal dysfunction may be adopted in the clinical setting in the near future. This article provides a general overview of cardiorenal syndrome and an update of the physiopathological mechanisms involved. Special emphasis is placed on the role of visceral congestion as an emergent mechanism in this syndrome.

  7. Prevalence and Prognostic Significance of Hyponatremia in Patients with Acute Exacerbation of Chronic Obstructive Pulmonary Disease: Data from the Akershus Cardiac Examination (ACE) 2 Study

    PubMed Central

    Brynildsen, Jon; Høiseth, Arne Didrik; Følling, Ivar; Brekke, Pål H.; Christensen, Geir; Hagve, Tor-Arne; Verbalis, Joseph G.; Omland, Torbjørn; Røsjø, Helge

    2016-01-01

    Background Hyponatremia is prevalent and associated with mortality in patients with heart failure (HF). The prevalence and prognostic implications of hyponatremia in acute exacerbation of chronic obstructive pulmonary (AECOPD) have not been established. Method We included 313 unselected patients with acute dyspnea who were categorized by etiology of dyspnea according to established guidelines (derivation cohort). Serum Na+ was determined on hospital admission and corrected for hyperglycemia, and hyponatremia was defined as [Na+]<137 mmol/L. Survival was ascertained after a median follow-up of 816 days and outcome was analyzed in acute HF (n = 143) and AECOPD (n = 83) separately. Results were confirmed in an independent AECOPD validation cohort (n = 99). Results In the derivation cohort, median serum Na+ was lower in AECOPD vs. acute HF (138.5 [135.9–140.5] vs. 139.2 [136.7–141.3] mmol/L, p = 0.02), while prevalence of hyponatremia (27% [22/83] vs. 20% [29/143], p = 0.28) and mortality rate (42% [35/83] vs. 46% [66/143], p = 0.56) were similar. By univariate Cox regression analysis, hyponatremia was associated with increased mortality in acute HF (HR 1.85 [95% CI 1.08, 3.16], p = 0.02), but not in AECOPD (HR 1.00 [0.47, 2.15], p = 1.00). Analogous to the results of the derivation cohort, hyponatremia was prevalent also in the AECOPD validation cohort (25% [25/99]), but not associated with mortality. The diverging effect of hyponatremia on outcome between AECOPD and acute HF was statistically significant (p = 0.04). Conclusion Hyponatremia is prevalent in patients with acute HF and AECOPD, but is associated with mortality in patients with acute HF only. PMID:27529844

  8. Respiratory High-Dependency Care Units for the burden of acute respiratory failure.

    PubMed

    Scala, Raffaele

    2012-06-01

    The burden of acute respiratory failure (ARF) has become one of the greatest epidemiological challenges for the modern health systems. Consistently, the imbalance between the increasing prevalence of acutely de-compensated respiratory diseases and the shortage of high-daily cost ICU beds has stimulated new health cost-effective solutions. Respiratory High-Dependency Care Units (RHDCU) provide a specialised environment for patients who require an "intermediate" level of care between the ICU and the ward, where non-invasive monitoring and assisted ventilation techniques are preferentially applied. Since they are dedicated to the management of "mono-organ" decompensations, treatment of ARF patients in RHDCU avoids the dangerous "under-assistance" in the ward and unnecessary "over-assistance" in ICU. RHDCUs provide a specialised quality of care for ARF with health resources optimisation and their spread throughout health systems has been driven by their high-level of expertise in non-invasive ventilation (NIV), weaning from invasive ventilation, tracheostomy care, and discharging planning for ventilator-dependent patients.

  9. First-principles study of electronic properties of La2Hf2O7 and Gd2Hf2O7

    SciTech Connect

    Li, Ni; Xiao, H. Y.; Zu, Xiaotao T.; Wang, Lumin M.; Ewing, R. C.; Lian, Jie; Gao, Fei

    2007-09-15

    The structural and electronic properties of A2Hf2O7 (A=La and Gd) pyrochlore compounds are investigated by means of first-principles total energy calculations. Also, the formation energies of defects are calculated, and the results can be used to explain the stability of pyrochlores. Hybridizations between A 5p and O 2s and between A 5d and O 2p states are observed, but the interaction between A 5p and O 2s orbitals is much stronger in Gd2Hf2O7 than that in La2Hf2O7. Gd2Hf2O7 compound shows much different density of state distribution from that of La2Hf2O7. Mulliken overlap population analysis shows that the A-O48f and A-O8b bonds in Gd2Hf2O7 are more ionic than the corresponding bonds in La2Hf2O7, while the Hf-O48f bond in Gd2Hf2O7 is more covalent. These calculations suggest that A-O48f and A-O8b bonds may play important roles in their responses to irradiation-induced amorphization observed experimentally.

  10. Action mechanism of hydrogen gas on deposition of HfC coating using HfCl4-CH4-H2-Ar system

    NASA Astrophysics Data System (ADS)

    Wang, Yalei; Li, Zehao; Xiong, Xiang; Li, Xiaobin; Chen, Zhaoke; Sun, Wei

    2016-12-01

    Hafnium carbide coatings were deposited on carbon/carbon composites by low pressure chemical vapor deposition using HfCl4-CH4-H2-Ar system. The microstructure, mechanical and ablation resistance performance of HfC coatings deposited with various H2 concentrations were investigated. The effect of hydrogen gas on the deposition of HfC coating was also discussed. Results show that all of the deposited coatings are composed of single cubic HfC phase, the hydrogen gas acted as a crucial role in determining the preferred orientation, microstructure and growth behavior of HfC coatings. During the deposition process, the gas phase supersaturation of the reaction species can be controlled by adjusting the hydrogen gas concentration. When deposited with low hydrogen gas concentration, the coating growth was dominated by the nucleation of HfC, which results in the particle-stacked structure of HfC coating. Otherwise, the coating growth was dominated by the crystal growth at high hydrogen gas concentration, which leads to the column-arranged structure of HfC coating. Under the ablation environment, the coating C2 exhibits better configurational stability and ablation resistance. The coating structure has a significant influence on the mechanical and ablation resistance properties of HfC coating.

  11. Characterization of nanostructured HfO 2 films using RBS and PAC

    NASA Astrophysics Data System (ADS)

    Cavalcante, F. H. M.; Gomes, M. R.; Carbonari, A. W.; Pereira, L. F. D.; Rossetto, D. A.; Costa, M. S.; Alves, E.; Barradas, N. P.; Franco, N.; Redondo, L. M.; Lopes, A. M. L.; Soares, J. C.

    2012-02-01

    The hyperfine field at 181Ta lattice sites in a nanostructured HfO 2 thin film doped with Fe was studied using Rutherford Backscattering Spectrometry and Perturbed Angular Correlation techniques. The 409 nm Hf film was deposited by Electron Beam Evaporation on a silicon substrate. The radioactive 181Hf ions were produced by neutron activation of the nanofilm in the Brazilian Research Reactor (IPEN IEA-R1) by the reaction 180Hf(n,γ) 181Hf. These studies provided an excellent opportunity to obtain unique information regarding local arrangement of the grains, structure, phase transformations of nanoparticles and interfaces of nanostructured materials and the thin film.

  12. Acute-on-chronic liver failure: terminology, mechanisms and management.

    PubMed

    Sarin, Shiv K; Choudhury, Ashok

    2016-03-01

    Acute-on-chronic liver failure (ACLF) is a distinct clinical entity and differs from acute liver failure and decompensated cirrhosis in timing, presence of acute precipitant, course of disease and potential for unaided recovery. The definition involves outlining the acute and chronic insults to include a homogenous patient group with liver failure and an expected outcome in a specific timeframe. The pathophysiology of ACLF relates to persistent inflammation, immune dysregulation with initial wide-spread immune activation, a state of systematic inflammatory response syndrome and subsequent sepsis due to immune paresis. The disease severity and outcome can be predicted by both hepatic and extrahepatic organ failure(s). Clinical recovery is expected with the use of nucleoside analogues for hepatitis B, and steroids for severe alcoholic hepatitis and, possibly, severe autoimmune hepatitis. Artificial liver support systems help remove toxins and metabolites and serve as a bridge therapy before liver transplantation. Hepatic regeneration during ongoing liver failure, although challenging, is possible through the use of growth factors. Liver transplantation remains the definitive treatment with a good outcome. Pre-emptive antiviral agents for hepatitis B before chemotherapy to prevent viral reactivation and caution in using potentially hepatotoxic drugs can prevent the development of ACLF.

  13. What Is Decompensated Cirrhosis?

    MedlinePlus

    ... the Media Room Public Affairs News Releases Speeches Videos Publications National Observances Veterans Day Memorial Day Celebrating America's Freedoms Special Events Adaptive Sports Program Creative Arts Festival Golden Age Games Summer Sports Clinic Training - Exposure - Experience (TEE) Tournament ...

  14. What Is Decompensated Cirrhosis?

    MedlinePlus

    ... Celebrating America's Freedoms Special Events Adaptive Sports Program Creative Arts Festival Golden Age Games Summer Sports Clinic ... used terms Resources return to top CONNECT Veterans Crisis Line: 1-800-273-8255 (Press 1) Social ...

  15. Saturated hydrides in the HfV{sub 2}-D system

    SciTech Connect

    Bogdanova, A. N. Irodova, A. V.; Andre, G.

    2007-05-15

    Saturated solid solutions of hydrogen (deuterium) are synthesized up to the ratio D/HfV{sub 2} = 5.1 for the HfV{sub 2} compound with a structure of the cubic Laves phase (the C15 type) and the HfV{sub 2}-based alloys (Hf{sub 0.7}Zr{sub 0.3})V{sub 2} and Hf(V{sub 0.92}Ti{sub 0.08}){sub 2} with partial substitution. The structure of the solid solutions is studied using neutron diffraction at room temperature. The saturated solid solutions of hydrogen are disordered: hydrogen occupies tetrahedral interstices 2Hf + 2V and 1Hf + 3V. The concentration of hydrogen in the solid solutions increases as the occupancy of the 1Hf + 3V interstices increases to the maximum value p{sub 1Hf+3V} {approx} 0.46, whereas the occupancy of the 2Hf + 2V interstices remains constant and equal to p{sub 2Hf+2V} {approx} 0.28. The maximum hydrogen concentration depends linearly on the lattice parameter of the initial intermetallic compound.

  16. Effect of magnetic storms (substorms) on HF propagation: A review

    NASA Astrophysics Data System (ADS)

    Blagoveshchenskii, D. V.

    2013-07-01

    The manifestations of the so-called main ionospheric effect during geomagnetic storms (substorms) in the character of decameter-wave propagation are analyzed. On HF radio paths, the main effect is observed as variations in the signal amplitude and the MOF-LOF working frequency band similarly to the critical frequency of the ionospheric F2 layer. Specifically, these parameters increase before the disturbance active phase, decrease during the active phase, and increase again after this phase. The propagation outside the great circle arc, the change in the propagation processes, and the HF radio noise behavior were also considered on these paths during storms (substorms). It is assumed that the storm (substorm) development onset can be predicted.

  17. Vibration-Rotation Bands of HF and DF

    DTIC Science & Technology

    1977-09-23

    studies on v -. R energy-transfer processes in the HF and DF systems required rotation-vibration energy terms and band centers for both HF and DF...N or- M o 0m Nr- 4r lO’ z ’OW 0 󈧈- l4-M N.4 00’o 040 oAM af NIN NNf- NN N N- N-I 14.4 -144 0 0 r 4-1 0 04 N t 𔃺NO W. .4 N . of- N utut M rl-0 M NO...propagation of plasmn wavea in the magnetosphere; solar physics, studies of solar magnetic fields; space astronomy, x-ray astronomy; the effects of nuclear

  18. Performance Analysis of HF Band FB-MC-SS

    SciTech Connect

    Hussein Moradi; Stephen Andrew Laraway; Behrouz Farhang-Boroujeny

    2016-01-01

    Abstract—In a recent paper [1] the filter bank multicarrier spread spectrum (FB-MC-SS) waveform was proposed for wideband spread spectrum HF communications. A significant benefit of this waveform is robustness against narrow and partial band interference. Simulation results in [1] demonstrated good performance in a wideband HF channel over a wide range of conditions. In this paper we present a theoretical analysis of the bit error probably for this system. Our analysis tailors the results from [2] where BER performance was analyzed for maximum ration combining systems that accounted for correlation between subcarriers and channel estimation error. Equations are give for BER that closely match the simulated performance in most situations.

  19. HF Doppler observations of acoustic waves excited by the earthquake

    NASA Technical Reports Server (NTRS)

    Ichinose, T.; Takagi, K.; Tanaka, T.; Okuzawa, T.; Shibata, T.; Sato, Y.; Nagasawa, C.; Ogawa, T.

    1985-01-01

    Ionospheric disturbances caused by the earthquake of a relatively small and large epicentral distance have been detected by a network of HF-Doppler sounders in central Japan and Kyoto station, respectively. The HF-Doppler data of a small epicentral distance, together with the seismic data, have been used to formulate a mechanism whereby ionospheric disturbances are produced by the Urakawa-Oki earthquake in Japan. Comparison of the dynamic spectra of these data has revealed experimentally that the atmosphere acts as a low-pass filter for upward-propagating acoustic waves. By surveying the earthquakes for which the magnitude M is larger than 6.0, researchers found the ionospheric effect in 16 cases of 82 seismic events. As almost all these effects have occurred in the daytime, it is considered that it may result from the filtering effect of the upward-propagating acoustic waves.

  20. HF-LPLI-treated tumor cells induce NO production in macrophage

    NASA Astrophysics Data System (ADS)

    Lu, Cuixia; Zhou, Feifan; Wu, Shengnan; Xing, Da

    2013-02-01

    High fluence low-power laser irradiation (HF-LPLI) provides a new stimulator to trigger cell apoptosis, and it is well known that apoptotic cells provide antigens to effectively trigger recognition by the immune system. In order to investigate the effect of HF-LPLI on the professional antigen-presenting cell (APC) function, in our primary study, we focused our attention on the effect of HF-LPLI-treated tumor cells on macrophages phagocytosis and NO production. Both confocal microscopy and flowcytometry analysis showed that HF-LPLI (120 J/cm2) induced significantly EMT6 death. Further experiments showed that HF-LPLI-treated EMT6 cells could be phagocyted by the murine macrophage cells RAW264.7, and could induce NO production in macrophages. Taken together, our results indicate that HF-LPLI-treated tumor cells effectively regulated the immune system. The HF-LPLI effect on the APC function needs to be further studied.

  1. Investigation of new type Cu-Hf-Al bulk glassy alloys

    NASA Astrophysics Data System (ADS)

    Nagy, E.; Rontó, V.; Sólyom, J.; Roósz, A.

    2009-01-01

    In the last years new type Cu-Hf-Al ternary alloys were developed with high glass forming ability and ductility. The addition of Al to Cu-Hf alloys results in improvements in glass formation, thermal stability and mechanical properties of these alloys. We have investigated new Cu-based bulk amorphous alloys in Cu-Hf-Al ternary system. The alloys with Cu49Hf42Al9, Cu46Hf45Al9, Cu50Hf42.5Al7.5 and Cu50Hf45Al5 compositions were prepared by arc melting. The samples were made by centrifugal casting and were investigated by X-ray diffraction method. Thermodynamic properties were examined by differential scanning calorimetry and the structure of the crystallising phases by scanning electron microscopy. The determination of liquidus temperatures of alloys were measured by differential thermal analysis.

  2. Ablation Studies of Enamel Tissue Using Pulsed HF Laser

    DTIC Science & Technology

    2007-11-02

    and enamel has been successful. The reason is thought to be due to high absorption coefficients of hydroxyapatite [Ca10(Po4)6(OH2)] with a total...secondary absorption peak of hydroxyapatite lies, a less violent and cleaner ablation of enamel compared with its main absorption peak at 9.6 µm is...1 of 4 Ablation Studies of Enamel Tissue using Pulsed HF Laser M.E. Khosroshahi, B.A. Ghasemi Amirkabir University of Technology, School of

  3. Simultaneous optical and HF radar observations of the ionsopheric cusp

    SciTech Connect

    Rodger, A.S.; Mende, S.B.; Rosenberg, T.J.; Baker, K.B.

    1995-08-01

    Simultaneous optical all-sky imager and photometer data from South Pole station and the PACE HF radar at Halley, Antarctica from two case studies are used to show that their respective ionospheric signatures of the magnetospheric cusp are collocated to better than about 1{degrees} latitude. The plasma convection reversal as identified in the PACE data is usually observed within the region showing cusp precipitation, as expected from contemporary models of this region of geospace. 21 refs., 3 figs., 1 tab.

  4. UHF electromagnetic emission stimulated by HF pumping of the ionosphere

    NASA Astrophysics Data System (ADS)

    Grach, S. M.; Fridman, V. M.; Lifshits, L. M.; Podstrigach, T. S.; Sergeev, E. N.; Snegirev, S. D.

    2002-10-01

    UHF electromagnetic emission (with a frequency near 600 MHz) from the F-region of the ionosphere pumped by an HF powerful radio wave is revealed. Possible mechanisms of the emission excitation, such as plasma mode con-version, scattering or Earth thermal noise emission off the plasma density irregularities, bremsstrahlung and excitation of high Rydberg states of the neutral particles by the accelerated electrons are discussed.

  5. On the Onset of HF-Induced Airglow at HAARP

    DTIC Science & Technology

    2007-11-02

    revised 2 December 2003; accepted 19 December 2003; published 13 February 2004. [i] Observations of airglow at 630 nm (red line) and 557.7 nm ( green ...during injections toward magnetic zenith (MZ) the green and red lines gain -5 R within ,-1 s and -20 R within ,-,10 s, respectively. We term this period...observations show that the airglow maximizes Gustavsson et al., 2001, 2002; Kosch et al., 2000, 2002]. during HF injections toward magnetic zenith

  6. Ferroelectric HfO2 for Emerging Ferroelectric Semiconductor Devices

    NASA Astrophysics Data System (ADS)

    Florent, Karine

    The spontaneous polarization in ferroelectrics (FE) makes them particularly attractive for non-volatile memory and logic applications. Non-volatile FRAM memories using perovskite structure materials, such as Lead Zirconate Titanate (PZT) and Strontium Bismuth Tantalate (SBT) have been studied for many years. However, because of their scaling limit and incompatibility with CMOS beyond 130 nm node, floating gate Flash memory technology has been preferred for manufacturing. The recent discovery of ferroelectricity in doped HfO2 in 2011 has opened the door for new ferroelectric based devices compatible with CMOS technology, such as Ferroelectric Field Effect Transistor (FeFET) and Ferroelectric Tunnel Junctions (FTJ). This work began with developing ferroelectric hysteresis characterization capabilities at RIT. Initially reactively sputtered aluminum doped HfO 2 films were investigated. It was observed that the composition control using co-sputtering was not achievable within the existing capabilities. During the course of this study, collaboration was established with the NaMLab group in Germany to investigate Si doped HfO2 deposited by Atomic Layer Deposition (ALD). Metal Ferroelectric Metal (MFM) devices were fabricated using TiN as the top and bottom electrode with Si:HfO2 thickness ranging from 6.4 nm to 22.9 nm. The devices were electrically tested for P-E, C-V and I-V characteristics. Structural characterizations included TEM, EELS, XRR, XRD and XPS/Auger spectroscopy. Higher remanant polarization (Pr) was observed for films of 9.3 nm and 13.1 nm thickness. Thicker film (22.9 nm) showed smaller Pr. Devices with 6.4 nm thick films exhibit tunneling behavior showing a memristor like I-V characteristics. The tunnel current and ferroelectricity showed decrease with cycling indicating a possible change in either the structure or the domain configurations. Theoretical simulations using the improved FE model were carried out to model the ferroelectric behavior of

  7. Interface and bulk properties of HfO2 films

    NASA Astrophysics Data System (ADS)

    Biswas, Nivedita; Harris, Harlan; Choi, Kisik; Temkin, Henryk; Gangopadhyay, Shubhra

    2003-03-01

    HfO2 films of varying thickness were deposited on silicon and titanium by reactive electron beam evaporation. Metal gates of Titanium were deposited to form MIS and MIM structures. Capacitance-voltage and conductance-voltage measurements were performed to analyze the HfO2/Si interface and HfO2 bulk. For samples having thickness between 30 and 300 Å the C-V curves of the as-deposited samples were marked by charge leakage, huge hysteresis and frequency dispersion. However, annealing the sample in H2 ambient reduced charge leakage, hysteresis and the frequency dispersion of the C-V curves. A dielectric constant of the annealed films was calculated to be 17. The interface state density as calculated using the method of Nicollian and Brews was 2-3E10 cm-2eV-1 close to the midgap. To study the bulk properties, HfO2 films of thickness 2100 Å with platinum electrodes were deposited on silicon and titanium nitride. The C-V and G-V curves of both as-deposited and annealed samples were measured. Interface state density was found to be comparable to that of the thin samples. Thus the passivation of bulk and interface states with hydrogen annealing is independent of thickness. The gap state densities were found compatible with the observed hysteresis of the as-deposited ( 1E16-1E17 eV-1cm-3) and annealed sample (1E14-1E15eV-1cm-3).

  8. Modeling Study of a cw HF Resonance Transfer Laser Medium

    DTIC Science & Technology

    1983-09-30

    allowing any ORTL fluid element to remain in the pump beam no longer than 200 sec. At that point, V-R processes begin to degrade the gain. A potential ...lasing species are the same, has a potential for high overall efficiency. Namely, a large fraction of the photon flux from a pumping HF laser can be...converted efficiently into BF ORTL power. This potential high efficiency combines with features attractive to chemical laser system. Properties

  9. The equation of state of HF under shock compression

    SciTech Connect

    Fried, L E; Howard, W M

    1999-06-01

    We develop a model of chemical equilibrium mixtures containing the elements H, C, F. We show that the shock response of a wide variety of molecular and polymeric fluorocarbons can be modeled as a chemical equilibrium mixture of a small number of dissociation product molecules. HF is known to strongly associate in the supercritical fluid phase. We predict that such an association also occurs under shock conditions.

  10. Studies of wave phenomena using HF-induced scatter target

    NASA Astrophysics Data System (ADS)

    Blagoveshchenskaya, N.; Borisova, T.; Kornienko, V.; Rietveld, M.; Frolov, V.; Uryadov, V.; Kagan, L.; Yampolski, Y.; Vertogradov, G.; Kelley, M.

    Experimental results from Tromso and Sura heating experiments at high and mid-latitudes are examined It was shown that the combination of HF-induced target and bi-static HF Doppler radio scatter observations is a profitable method for the identification and studies of wave phenomena of different origin We analysed the ULF activity in the Pc 3-4 range and the medium-scale traveling ionospheric disturbances TIDs at high and mid-latitudes Bi-static HF Doppler radio scatter observations were carried out on the London-Tromso-St Petersburg path in the course of Tromso heating experiments During Sura heating experiments multi-position bi-static HF Doppler radio scatter observations were simultaneously performed at three reception points including St Petersburg Kharkov and Rostov-on-Don Ray tracing and Doppler shift simulations were made for all experiments Parameters of ULF waves were found The interesting feature detected from Sura heating experiment was the dependence of the ULF wave parameters from the effective radiated power of the heating facility Medium-scale TIDs were observed in the evening and pre-midnight hours TIDs in the auroral E region with periods of 20-25 min were traveling southward at speeds from 190-250 m s TIDs in the mid-latitudinal F region with periods from 15 to 45 min were at speeds between 40 and 120 m s During quiet magnetic conditions the waves were traveling in the north-east direction In disturbed conditions the waves were moving in the south-west direction with higher speeds as compared with quiet conditions Possible mechanisms

  11. Theoretical study of the dipole-bound anion (HF)2 -

    NASA Astrophysics Data System (ADS)

    Gutowski, Maciej; Skurski, Piotr

    1997-08-01

    It has long been assumed that dipole-bound anionic states possess two properties; (i) the electron binding energy is dominated by the electrostatic electron-dipole interaction, and (ii) the geometrical distortion of the polar molecule upon attachment of a distant electron is negligible. Our results indicate, however, that the dispersion interaction between the loosely bound electron and the electrons of the neutral dimer is as important as the electrostatic electron-dipole stabilization. In addition, the hydrogen bond in (HF)2 is susceptible to a deformation upon attachment of a distant electron. This deformation enhances both the electrostatic and dispersion components of the electron binding energy. The calculated Franck-Condon factors indicate that neutral dimers formed in electron photodetachment experiments may be vibrationally excited in both stiff intramolecular HF stretching modes and soft intermolecular modes. The predicted value of the adiabatic electron detachment energy for (HF)2- is 396 cm-1 and the theoretical photoelectron spectrum is in remarkable agreement with the experimental data of Bowen et al. J. H. Hendricks, H. L. de Clercq, S. A. Lyapustina, and K. H. Bowen, Jr. [J. Chem. Phys. 107, 2962 (1997)].

  12. Spectroscopic ellipsometry studies of HF treated Si (100) surfaces

    NASA Astrophysics Data System (ADS)

    Yao, Huade; Woollam, John A.; Alterovitz, Samuel A.

    1993-08-01

    Both ex situ and in situ spectroscopic ellipsometry (SE) measurements were employed to investigate the effects of HF cleaning on Si surfaces. The hydrogen-terminated (H-terminated) Si surface was modeled as an equivalent dielectric layer, and monitored in real time by SE measurements. The SE analyses indicate that after a 20-s 9:1 HF dip without rinse, the Si(100) surface was passivated by the hydrogen termination and remained chemically stable. Roughness of the HF-etched bare Si(100) surface was observed, in an ultrahigh vacuum (UHV) chamber, and analyzed by the in situ SE. Evidence for desorption of the H-terminated Si surface-layer, after being heated to approximately 550 C in the UHV chamber, is presented and discussed. This is the first use of an ex situ and in situ real-time, nondestructive technique capable of showing state of passivation, the rate of reoxidation, and the surface roughness of the H-terminated Si surfaces.

  13. Spectroscopic ellipsometry studies of HF treated Si (100) surfaces

    NASA Astrophysics Data System (ADS)

    Yao, Huade; Woollam, John A.; Alterovitz, Samuel A.

    1993-06-01

    Both ex situ and in situ spectroscopic ellipsometry (SE) measurements were employed to investigate the effect of HF cleaning on Si surfaces. The hydrogen-terminated (H-terminated) Si surface was modeled as an equivalent dielectric layer, and monitored in real time by SE measurements. The SE analyses indicate that, after a 20-sec 9:1 HF dip without rinse, the Si (100) surface was passivated by the hydrogen termination and remained chemically stable. Roughness of the HF-etched bare Si (100) surface was observed, in an ultrahigh vacuum chamber (UHV), and analyzed by the in situ SE. Evidence for desorption of the H-terminated Si surface layer, after being heated to about 550 C in the UHV chamber, is presented and discussed. This is the first use of an ex situ and in situ real-time, nondestructive technique capable of showing state of passivation, the rate of reoxidation, and the surface roughness of the H-terminated Si surfaces.

  14. Oxidation behavior of FeAl+Hf,Zr,B

    NASA Technical Reports Server (NTRS)

    Smialek, James L.; Doychak, Joseph

    1988-01-01

    The oxidation behavior of Fe-40Al-1Hf, Fe-40Al-1Hf-0.4B, and Fe-40Al-0.1Zr-0.4B (at. percent) alloys was characterized after 900, 1000, and 100 C exposures. Isothermal tests revealed parabolic kinetics after a period of transitional theta-alumina scale growth. The parabolic growth rates for the subsequent alpha-alumina scales were about five times higher than those for NiAl+0.1Zr alloys. The isothermally grown scales showed a propensity toward massive scale spallation due to both extensive rumpling from growth stresses and to an inner layer of HfO2. Cyclic oxidation for 200 1-hr cycles produced little degradation at 900 or 1000 C, but caused significant spallation at 1100 C in the form of small segments of the outer scale. The major difference in the cyclic oxidation of the three FeAl alloys was increased initial spallation for FeAl+Zr,B. Although these FeAl alloys showed many similarities to NiAl alloys, they were generally less oxidation resistant. It is believed that this resulted from nonoptimal levels of dopants and larger thermal expansion mismatch stresses.

  15. Cross-correlation trajectory study of vibrational relaxation of HF (v=1--7) by HF (v=0)

    SciTech Connect

    Coltrin, M.E.; Marcus, R.A.

    1980-11-01

    Results are presented for a three-dimensional quasiclassical trajectory study of the vibrational deactivation of vibrationally excited HF (v=1--7) by ground vibrational HF. A cross-correlation method of analysis is used to calculate probabilities and rate constants for V--V and V--RT transitions using trajectory results. Comparisons are made of calculated total deactivation rate constants (V--V plus V--RT) with experimental values. The V--RT dominates the relaxation for higher v states, and increases particularly rapidly with increasing v. Comparisons are made with recent classical-path calculations for this system, and in the use of Morse versus equivalent harmonic oscillator potentials.

  16. Anion Exchange Behavior Of Ti, Zr, Hf, Nb And Ta As Homologues Of Rf And Db In Mixed HF--Acetone Solutions

    SciTech Connect

    Aksenov, N. V.; Bozhikov, G. A.; Starodub, G. Ya.; Dmitriev, S. N.; Filosofov, D. V.; Sun Jin, Jon; Radchenko, V. I.; Lebedev, N. A.; Novgorodov, A. F.

    2010-04-30

    We studied in detail the sorption behavior of Ti, Zr, Hf, Nb and Ta on AG 1 anion exchange resin in HF-acetone mixed solutions as a function of organic cosolvent and acid concentrations. Anion exchange behavior was found to be strongly acetone concentration dependent. The distribution coefficients of Ti, Zr, Hf and Nb increased and those of Ta decreased with increasing content of acetone in HF solutions. With increasing HF concentration anion exchange equilibrium analysis indicated the formation of fluoride complexes of group 4 elements with charge-3 and Ta---2. For Nb the slope of-2 increased up to-5. Optimal conditions for separation of the elements using AIX chromatography were found. Group 4 elements formed MF{sub 7}{sup 3-} (M = Ti, Zr, Hf) complexes whose sorption decreased Ti>Hf>Zr in reverse order of complex stability. This fact is of particular interest for studying ion exchange behavior of Rf compared to Ti. The advantages of studying chemical properties of Rf and Db in aqueous HF solutions mixed with organic solvents are briefly discussed.

  17. Formation and thermal stability of an E9{sub 3}-structured NiHf{sub 2} phase in Ni{sub 33}Hf{sub 67}

    SciTech Connect

    Liu, X.D. . E-mail: liuxd@physics.mcgill.ca; Liu, X.B.; Altounian, Z.

    2005-03-01

    The melt-spun Ni{sub 33}Hf{sub 67} glassy phase completely crystallizes into an fcc NiHf{sub 2} phase (a {approx} 12 A) upon continuous heating or isothermal annealing. Kinetics analysis shows that the NiHf{sub 2} grains are crystallized by nucleation and diffusion-controlled growth of nuclei at an average activation energy of {approx}400 kJ/mol. The resulting NiHf{sub 2} grains are extremely fine, {approx}10 nm in diameter, and exhibit excellent grain size stability upon subsequent heating over a wide temperature range. The Wigner-Seitz cell calculation results suggest that the fcc phase could be oxygen-stabilized. In the fcc lattice, the octahedral interstitial site with six nearest Hf neighbors is the most likely site for an oxygen atom to occupy. Upon further heating, part of the fcc NiHf{sub 2} crystals transform into two bct phases: the equilibrium bct NiHf{sub 2} and a metastable bct phase with a larger unit cell. Similar to the fcc phase, the metastable bct phase is most likely oxygen-stabilized. We show that the most likely oxygen site in the metastable bct lattice is the center of a tetrahedron with four nearest Hf neighbors. Upon further isothermal annealing at higher temperatures, close to the melting point of the alloy, the transformation from the metastable bct to the stable bct phase takes place.

  18. Lu-Hf and PbSL geochronology of apatites from Proterozoic terranes: A first look at Lu-Hf isotopic closure in metamorphic apatite

    NASA Astrophysics Data System (ADS)

    Barfod, Gry Hoffmann; Krogstad, Eirik Jens; Frei, Robert; Albarède, Francis

    2005-04-01

    The mineral apatite is characterized by elevated and highly variable Lu/Hf ratios that, in some cases, allow for single-crystal dating by the Lu-Hf isotopic system. Apatites from the Adirondack Lowlands and Otter Lake area in the Grenville Province, and from the Black Hills, South Dakota, yield Lu-Hf ages that are consistently older than their respective Pb step leaching ages. Isotopic closure for the Lu-Hf system, therefore, occurs before U-Pb system closure in this mineral. In the Adirondack Lowlands, where H 2O activity was low, Lu-Hf systematics of cm-sized apatite crystals remained undisturbed during upper amphibolite facies metamorphism (˜700 to 675 °C) at 1170-1130 Ma. The relatively old Lu-Hf ages of 1270 and 1230 Ma observed for these apatites correlate with decreasing crystal size. In contrast, apatite from the fluid-rich Otter Lake area and Black Hills yields unrealistically low apparent Lu-Hf closure temperatures, implying that in these apatites, fluids facilitated late exchange. The Lu-Hf ages for the metamorphic apatites were thus controlled either by the prevailing temperature and grain size, or by fluid activity.

  19. Experimental and theoretical study of electro-optics of molecular dimers OC...HF and HCN...HF

    NASA Astrophysics Data System (ADS)

    Bulanin, Michael O.; Bulychev, V. P.; Tokhadze, K. G.; Uspensky, A. I.

    1997-03-01

    We report an experimental study of the band shapes and relative IR intensities for the stretching v1 and librational vL modes of the HF subunit in complexes with OC and HCN. The ratio of the transition dipole moments for the v1 and vL bands is found to be close to unity. The relative intensities of the stretching and librational modes in typical H-bonded species (CH3)2CO. . .HF and (CH3)2O. . .HF are also measured for comparison. A multidimensional quantum mechanical problem of the relative motion of monomers in complexes is solved using model intermolecular interaction potentials and the wave functions expanded in products of 1D-basis functions. Classification of the states of relative motions of monomers is made by considering various cuts through the wave functions. Motions involving different degrees of freedom are shown to be strongly coupled. The frequencies and transition probabilities of the low-frequency modes are computed. The vibrationally averaged electro-optic parameters of complexes evaluated in the framework of the electrostatic induction model are in satisfactory agreement with the experimental data.

  20. Noninvasive mechanical ventilation in chronic obstructive pulmonary disease and in acute cardiogenic pulmonary edema.

    PubMed

    Rialp Cervera, G; del Castillo Blanco, A; Pérez Aizcorreta, O; Parra Morais, L

    2014-03-01

    Noninvasive ventilation (NIV) with conventional therapy improves the outcome of patients with acute respiratory failure due to hypercapnic decompensation of chronic obstructive pulmonary disease (COPD) or acute cardiogenic pulmonary edema (ACPE). This review summarizes the main effects of NIV in these pathologies. In COPD, NIV improves gas exchange and symptoms, reducing the need for endotracheal intubation, hospital mortality and hospital stay compared with conventional oxygen therapy. NIV may also avoid reintubation and may decrease the length of invasive mechanical ventilation. In ACPE, NIV accelerates the remission of symptoms and the normalization of blood gas parameters, reduces the need for endotracheal intubation, and is associated with a trend towards lesser mortality, without increasing the incidence of myocardial infarction. The ventilation modality used in ACPE does not affect the patient prognosis.

  1. Acute-on-chronic liver failure: a new syndrome in cirrhosis.

    PubMed

    Moreau, Richard

    2016-03-01

    Patients with cirrhosis who are hospitalized for an acute decompensation (AD) and also have organ failure(s) are at high risk of short-term death. These patients have a syndrome called Acute-on-Chronic Liver Failure (ACLF). ACLF is now considered as a new syndrome that it is distinct from "mere" AD not only because of the presence of organ failure(s) and high short-term mortality but also because of younger age, higher prevalence of alcoholic etiology of cirrhosis, higher prevalence of some precipitants (such as bacterial infections, active alcoholism), and more intense systemic inflammatory response. ACLF is a new syndrome also because severe sepsis or severe alcoholic hepatitis do not account for 100% of the observed cases; in fact, almost 50% of the cases are of "unknown" origin. In other words, severe sepsis, severe alcoholic hepatitis and ACLF of "unknown origin" are subcategories of the syndrome.

  2. Electron beam induced local crystallization of HfO2 nanopores for biosensing applications

    NASA Astrophysics Data System (ADS)

    Shim, Jiwook; Rivera, Jose A.; Bashir, Rashid

    2013-10-01

    We report the development of single, locally crystallized nanopores in HfO2 membranes for biosensing applications. HfO2 is chosen for its isoelectric point of 7.0, mechanical and chemical stability in solution, and for its potential as a high-k material for nanopore ionic field effect transistor applications. The HfO2 membrane is deposited on a graphene layer suspended over a 300 nm FIB hole, where graphene is used as the mechanical support. Exposure of the membrane to a focused electron beam causes crystallization in the vicinity of the nanopore during pore formation. We investigate the effects of crystallization on the electrical and surface properties of HfO2 films. Our surface analysis of HfO2 reveals improved hydrophilicity of crystallized HfO2, a notable advantage over the hydrophobicity of as-deposited HfO2. We also demonstrate detection of dsDNA translocation through HfO2 nanopores under various applied bias levels. In addition, our device architecture also presents a promising first step toward the realization of high-k HfO2 nanopore transistors.We report the development of single, locally crystallized nanopores in HfO2 membranes for biosensing applications. HfO2 is chosen for its isoelectric point of 7.0, mechanical and chemical stability in solution, and for its potential as a high-k material for nanopore ionic field effect transistor applications. The HfO2 membrane is deposited on a graphene layer suspended over a 300 nm FIB hole, where graphene is used as the mechanical support. Exposure of the membrane to a focused electron beam causes crystallization in the vicinity of the nanopore during pore formation. We investigate the effects of crystallization on the electrical and surface properties of HfO2 films. Our surface analysis of HfO2 reveals improved hydrophilicity of crystallized HfO2, a notable advantage over the hydrophobicity of as-deposited HfO2. We also demonstrate detection of dsDNA translocation through HfO2 nanopores under various applied

  3. Influence of Hf4+ ions concentration on the defect structure and exposure energy in Hf:Ho:LiNbO3

    NASA Astrophysics Data System (ADS)

    Dai, Li; Li, Dayong; Xu, Chao; Guo, Jingjie; Xu, Yuheng

    2013-02-01

    A series of Hf:Ho:LiNbO3 crystals with various levels of HfO2 doping were grown by the conventional Czochraski technique. The measurement of the Hf and Ho concentrations in the crystals was carried out with an inductively coupled plasma atomic emission spectrometer (ICP-OE/MS). The infrared (IR) spectrum was measured in order to analyze the defect structure of the crystals. The light-induced scattering was characterized quantitatively via the incident exposure energy. The results showed that the ability to resist the light-induced scattering was improved considerably with the increase in concentration of Hf4+, however, light-induced scattering resistance ability weakened as the concentration of Hf4+ surpasses the concentration to 8 mol%. The relationship between the defect structures and the light-induced scattering was discussed.

  4. Empirical Study of the Multiaxial, Thermomechanical Behavior of NiTiHf Shape Memory Alloys

    NASA Technical Reports Server (NTRS)

    Shukla, Dhwanil; Noebe, Ronald D.; Stebner Aaron P.

    2013-01-01

    An empirical study was conducted to characterize the multiaxial, thermomechanical responses of new high temperature NiTiHf alloys. The experimentation included loading thin walled tube Ni(sub 50.3)Ti(sub 29.7)Hf(sub 20) alloy samples along both proportional and nonproportional axial-torsion paths at different temperatures while measuring surface strains using stereo digital image correlation. A Ni(sub 50.3)Ti(sub 33.7)Hf(sub 16) alloy was also studied in tension and compression to document the effect of slightly depleting the Hf content on the constitutive responses of NiTiHf alloys. Samples of both alloys were made from nearly texture free polycrystalline material processed by hot extrusion. Analysis of the data shows that very small changes in composition significantly alter NiTiHf alloy properties, as the austenite finish (Af) temperature of the 16-at Hf alloy was found to be approximately 60 C less than the 20-at Hf alloy (approximately 120 C vs. 180 C). In addition, the 16-at Hf alloy exhibited smaller compressive transformation strains (2 vs. 2.5 percent). Multi-axial characterization of the 20-at % Hf alloy showed that while the random polycrystal transformation strains in tension (4 percent) and compression (2.5 percent) are modest in comparison with binary NiTi (6 percent, 4 percent), the torsion performance is superior (7 vs. 4 shear strain width to the pseudoelastic plateau).

  5. The New England Batholith of eastern Australia: Evidence of silicic magma mixing from zircon 176 Hf/ 177 Hf ratios

    NASA Astrophysics Data System (ADS)

    Shaw, S. E.; Flood, R. H.; Pearson, N. J.

    2011-09-01

    Zircon Hf isotopic data from six granite supersuites recognised in the New England Batholith of eastern Australia indicate that magma mixing is present in all plutons. Apart from the S-type supersuites, inherited zircons are rare to absent, suggesting that initial melt temperatures were above zircon saturation for the M-, I- and A-type granites. In all supersuites, the range of zircon Hf model ages calculated relative to arc mantle varies greatly, with younger model ages somewhat less than the Permian and Triassic age of crystallisation, and older model ages indicating derivation from source rocks that may be as old as Neoproterozoic. The older model ages are consistent with late Precambrian rocks in the lower crust that may be elements of the Lachlan Fold Belt underlying the New England Fold Belt. Whole-rock δ 18O and ɛNd values, 87Sr/ 86Sr initial ratios (Sr i) and oxidation state (Fe 2O 3/FeO) are summarised for the five named supersuites, and for a previously unnamed group of Triassic plutons situated east of the main Batholith for which we propose the name Carrai supersuite. Supersuites with higher δ 18O, higher Sr i, lower δ 7Li and lower Fe 2O 3/FeO ratios indicate a metasedimentary component input. The pattern of zircon Hf isotopic variation reflects the other isotopic and geochemical indicators closely, the additional value being that it preserves a magmatic crystallisation record of Hf isotopic variation, that is, a measure of magma mixing from magma generation to final crystallisation. Using the above criteria, at least three distinct crustal components are considered necessary to explain the compositional and isotopic diversity within the Batholith. The crustal components indicated are: 1) a metasedimentary component of Carboniferous and Devonian age for the Hillgrove, Bundarra and Uralla supersuites; 2) a lower crustal K-rich (and Sr-rich) I-type component for the Moonbi, Carrai and possibly Uralla supersuites that could be as old as Proterozoic

  6. Crystallography of the NiHfSi Phase in a NiAl (0.5 Hf) Single-Crystal Alloy

    NASA Technical Reports Server (NTRS)

    Garg, A.; Noebe, R. D.; Darolia, R.

    1996-01-01

    Small additions of Hf to conventionally processed NiAl single crystals result in the precipitation of a high density of cuboidal G-phase along with a newly identified silicide phase. Both of these phases form in the presence of Si which is not an intentional alloying addition but is a contaminant resulting from contact with the ceramic shell molds during directional solidification of the single-crystal ingots. The morphology, crystal structure and Orientation Relationship (OR) of the silicide phase in a NiAl (0.5 at.%Hf) single-crystal alloy have been determined using transmission electron microscopy, electron microdiffraction and energy dispersive X-ray spectroscopy. Qualitative elemental analysis and indexing of the electron microdiffraction patterns from the new phase indicate that it is an orthorhombic NiHfSi phase with unit cell parameters, a = 0.639 nm, b = 0.389 nm and c = 0.72 nm, and space group Pnma. The NiHfSi phase forms as thin rectangular plates on NiAl/111/ planes with an OR that is given by NiHfSi(100))(parallel) NiAl(111) and NiHfSi zone axes(010) (parallel) NiAl zone axes (101). Twelve variants of the NiHfSi phase were observed in the alloy and the number of variants and rectangular morphology of NiHfSi plates are consistent with symmetry requirements. Quenching experiments indicate that nucleation of the NiHfSi phase in NiAI(Hf) alloys is aided by the formation of NiAl group of zone axes (111) vacancy loops that form on the NiAl /111/ planes.

  7. An ab initio study of the C2H2-HF, C2H(CH3)-HF and C2(CH3)2-HF hydrogen-bonded complexes.

    PubMed

    Ramos, Mozart N; Lopes, Kelson C; Silva, Washington L V; Tavares, Alessandra M; Castriani, Fátima A; do Monte, Silmar A; Ventura, Elizete; Araújo, Regiane C M U

    2006-02-01

    MP2/6-31++G** and B3LYP/6-31++G** ab initio molecular orbital calculations have been performed in order to obtain molecular geometries, binding energies and vibrational properties of the C2H2-HF, C2H(CH3)-HF and C2(CH3)2-HF H-bonded complexes. As expected, the more pronounced effects on the structural properties of the isolated molecules due to complexation was verified for the C[triple bond]C and H-F bond lengths, which are directly involved in the H-bond formation. These bond distances increased after complexation. BSSE uncorrected B3LYP binding energies are always lower than the corresponding MP2 values. However, the opposite trend has been verified after BSSE correction by the counterpoise method since it is much lower at B3LYP than at MP2 level. The binding energies for these complexes as well as for the HF acid submolecule modes (the HF stretching and vibrational frequency modes) showed an increasing hydrogen-bonding strength with increasing methyl substitution. The splitting in the HF in-plane and out-of-plane bending modes reflects the anisotropy in the hydrogen-bonding interaction with the pi system of the C[triple bond]C bond. The H-F stretching frequency is shifted downward after complexation and it increases with the methyl substitution. The IR intensities of the HF acid submolecule fundamentals are adequately interpreted through the atomic polar tensor of the hydrogen atom using the charge-charge flux-overlap model. The skeletal stretching modes of the Alkyne submolecule are decreased in the complex. The new vibrational modes arising from complexation show several interesting features.

  8. Use of Lung Ultrasound For Diagnosing Acute Heart Failure in Emergency Department of Southern India

    PubMed Central

    Gupta, Mrigakshi; Vijan, Vikrant; Vupputuri, Anjith; Chintamani, Sanjeev; Rajendran, Bishnukiran; Thachathodiyal, Rajesh; Chandrasekaran, Rajiv

    2016-01-01

    Introduction Diagnosing heart failure is often a challenge for the healthcare providers due to it’s non-specific and usually subtle physical presentations. The outcomes for treatment are strongly related to the stage of the disease. Considering the importance of early and accurate diagnosis, it is important to have an easy, inexpensive, non-invasive, reliable and reproducible method for diagnosis of heart failure. Recent advancement in radiology and cardiology are supporting the emerging technique of lung ultrasound through B-line evaluation for identifying extravascular lung water. Aim To establish lung ultrasound as an easy, inexpensive, non-invasive, reliable and reproducible method for diagnosing Acute Decompensated Heart Failure (ADHF) in emergency department. Materials and Methods The study was a cross-sectional, prospective, observational, diagnostic validation study of lung ultrasound for diagnosis of acute heart failure in an emergency department and was performed at Amrita Institute of Medical Science, Kochi, Kerala, India. A total of 42 patients presenting with symptoms suggestive of acute decompensated heart failure were evaluated by plasma B-type Natriuretic Peptide (BNP), Echocardiography (ECHO) and X-ray. Lung ultrasound was done to look for the presence of B-lines. Statistical Analysis Sensitivity, specificity and predictive value of diagnostic modalities were calculated using Mc Nemar’s Chi-square test for the presence and absence of heart failure. Results Lung ultrasound showed a sensitivity of 91.9% and a specificity of 100% in diagnosing acute heart failure comparable to plasma BNP which had a sensitivity of 100% and a specificity of 60%. It was also superior to other methods of diagnosing ADHF namely X-ray and ECHO and showed a good association. Conclusion Lung ultrasound and its use to detect ultrasonographic B-lines is an early, sensitive and an equally accurate predictor of ADHF in the emergency setting as compared to BNP. PMID:28050472

  9. Effect of lamivudine treatment in patients with decompensated cirrhosis due to anti-HBe positive/HBeAg-negative chronic hepatitis B.

    PubMed

    Nikolaidis, Nikolaos; Vassiliadis, Themistoklis; Giouleme, Olga; Tziomalos, Konstantinos; Grammatikos, Nikolaos; Patsiaoura, Kalliopi; Orfanou-Koumerkeridou, Eleni; Balaska, Aikaterini; Eugenidis, Nikolaos

    2005-06-01

    Lamivudine has been shown to improve liver function and reduce the need for liver transplantation (LT) in patients with decompensated HBeAg-positive cirrhosis. Nevertheless, there is only limited experience with lamivudine in patients with anti-HBe-positive/HBeAg-negative cirrhosis. The primary aim of this study was to determine whether lamivudine treatment improves liver function and subsequently pre-LT survival or delays or obviates the need for LT in patients with anti-HBe-positive/HBeAg-negative cirrhosis. Between July 1998 and June 2003, 20 consecutive patients awaiting LT were enrolled in the study. All patients showed active viral replication and were treated with lamivudine 100 mg daily. Significant clinical improvement, defined as a decrease in the Child-Pugh-Turcotte score by >or=2 points, was observed in 11 (55%) patients. The median change in the Child-Pugh-Turcotte score was -2 (range -5 to +2). The median time required to achieve a 2-point or greater reduction in Child-Pugh-Turcotte score was 6 months (range 3-12 months). In nine patients (45%), the Child-Pugh-Turcotte score decreased to decompensated anti-HBe-positive/HBeAg-negative cirrhosis caused by actively replicating chronic hepatitis B.

  10. Heart failure trials on pharmacological therapy in 2015: lessons learned and future outlook.

    PubMed

    Latini, Roberto; Masson, Serge; Staszewsky, Lidia

    2016-06-01

    Much progress in the medical therapy of chronic heart failure (HF) has been made in the last decades. The last was the introduction of a new treatment strategy based on the combination of the neprilysin inhibitor sacubitril and the angiotensin receptor blocker (ARB) valsartan into the pharmacological armamentarium, as reported in the PARADIGM-HF trial and its ancillary analyses. On the other hand, in the acute setting only scant progress in pharmacological treatments has been achieved, and most published data are based on observational studies or expert opinion. This review critically presents and discusses the most intriguing evidence from clinical trials in HF published in 2015. In particular, we focused on chronic HF with reduced ejection fraction and its comorbidities, while worsening HF or acute decompensated HF were more synthetically treated.

  11. Predictors of Six-Month Mortality in BNP-Matched Acute Heart Failure Patients.

    PubMed

    Lourenço, Patrícia; Ribeiro, Ana; Pintalhão, Mariana; Silva, Sérgio; Bettencourt, Paulo

    2015-09-01

    Natriuretic peptides have established prognostic value in heart failure (HF). The role of many other clinical and laboratory variables is still to be proved. The aim of this study was to assess prognostic determinants of death in acute HF in B-type natriuretic peptide (BNP)-matched patients. We conducted a case-control study to assess prognostic predictors of 6-month mortality in acute HF. From a prospectively recruited population of hospital-admitted patients with acute HF, we retrospectively selected a convenience sample of age-, gender-, and admission BNP-matched patients who survived (controls) or died (cases) in the follow-up period. Prognostic predictors of death were analyzed using a Cox regression analysis. A multivariate model was built. Variables in the model included atrial fibrillation, hypertension, admission heart rate, systolic blood pressure, the New York Heart Association class, hemoglobin, urea, albumin, systolic dysfunction, ischemic etiology, prognostic-modifying therapy, and BNP decrease during hospitalization. We analyzed 224 patients: 112 surviving and 112 not surviving a 6-month period. Median age was 80 years, 42.9% of the patients were men, and 63.9% had systolic dysfunction. Patients surviving the first 6 months had higher admission systolic blood pressure and heart rate, higher hemoglobin, lower urea, and more often had >30% decrease in BNP during hospitalization; they were more often discharged on HF prognostic modifying therapy. However, in multivariate analysis, the only independent mortality predictor was BNP decrease: patients in whom BNP decreased >30% had an HR of death of 0.57 (0.37 to 0.89). In conclusion, in BNP-matched patients with acute HF, the only independent mortality predictor is BNP decrease. Other literature suggested death predictors do not seem independent of natriuretic peptides.

  12. Acute-on-chronic liver failure

    PubMed Central

    Asrani, Sumeet K; Simonetto, Douglas A; Kamath, Patrick S

    2015-01-01

    Over the last two decades, the concept of acute-on-chronic liver failure (ACLF) has been proposed as an alternate path in the natural history of decompensated cirrhosis. ACLF is thus characterized by the presence of a precipitating event (identified or unidentified) in subjects with underlying chronic liver disease leading to rapid progression of liver injury and ending in multi-organ dysfunction characterized by high short term mortality. Multiple organ failure and increased risk for mortality are key to diagnosis of ACLF. The prevalence of ACLF ranges from 24–40% in hospitalized patients. The pathophysiological basis of ACLF can be explained using a 4 part model of predisposing event, injury due to precipitating event, response to injury and organ failure. Though several mathematical scores have been proposed for identifying outcomes with ACLF, it is yet unclear whether these organ failure scores are truly prognostic or are only reflective of the dying process. Treatment paradigms continue to evolve but consist of early recognition, supportive intensive care, and consideration of liver transplantation prior to onset of irreversible multiple organ failure. PMID:26188138

  13. Morphine in the treatment of acute pulmonary oedema--Why?

    PubMed

    Ellingsrud, C; Agewall, S

    2016-01-01

    Morphine has for a long time, been used in patients with acute pulmonary oedema due to its anticipated anxiolytic and vasodilatory properties, however a discussion about the benefits and risks has been raised recently. A literature search in Medline and Embase using the keywords "pulmonary oedema" OR "lung oedema" OR "acute heart failure" AND "morphine" was performed. A certain vasodilation has been described after morphine administration, but the evidence for this mechanism is relatively poor and morphine-induced anxiolysis may possibly be the most important factor of morphine in pulmonary oedema and therefore some authors have suggested benzodiazepines as an alternative treatment. Respiratory depression seems to be a less relevant clinical problem according to the literature, whereas vomiting is common, which may cause aspiration. In the largest outcome study, based on the ADHERE registry, morphine given in acute decompensated heart failure was an independent predictor of increased hospital mortality, with an odds ratio of 4.8 (95% CI: 4.52-5.18, p<0.001). Other, smaller studies have shown a significant association between morphine administration and mortality, which was lost after adjusting for confounding factors. Morphine is still used for pulmonary oedema in spite of poor scientific background data. A randomised, controlled study is necessary in order to determine the effect--and especially the risk--when using morphine for pulmonary oedema. Since the positive effects are not sufficiently documented, and since the risk for increased mortality cannot be ruled out, one can advocate that the use should be avoided.

  14. Strong photoluminescence of the porous silicon with HfO2-filled microcavities

    NASA Astrophysics Data System (ADS)

    Jiang, Ran; Wu, Zhengran; Du, Xianghao; Han, Zuyin; Sun, Weideng

    2015-06-01

    Greatly enhanced blue emission was observed at room temperature in the single-crystal silicon with HfO2 filled into its microcavities. The broad blue band light was emitted from both the HfO2 dielectric and the porous Si. The ferroelectricity of HfO2 enhances the blue emission from Si by its filling into the microcaivities. At the same time, HfO2 contributes to the light emission for the transitions of the defect levels for oxygen vacancy. The observation of greatly enhanced blue light emission of the porous Si filled with HfO2 dielectric is remarkable as both HfO2 and Si are highly compatible with Si-based electronic industry.

  15. Corrosion characteristics of anodized Ti-(10-40wt%)Hf alloys for metallic biomaterials use.

    PubMed

    Jeong, Yong-Hoon; Choe, Han-Cheol; Brantley, William A

    2011-01-01

    The effect of anodizing on corrosion resistance of Ti-xHf alloys has been investigated. Ti-xHf alloys were prepared and anodized at 120, 170 and 220 V in 1 M H(3)PO(4) solution, and crystallized at 300 and 500°C. Corrosion experiments were carried out using a potentiostat in 0.15 M NaCl solution at 36.5 ± 1°C. The Ti-xHf alloys exhibited the α' and anatase phases. The pore size on the anodized surface increases as the applied voltage is increased, whereas the pore size decreases as the Hf content is increased. The anodized Ti-xHf alloys exhibited better corrosion resistance than non-anodized Ti-xHf alloys.

  16. Microstructure dependent filament forming kinetics in HfO2 programmable metallization cells

    NASA Astrophysics Data System (ADS)

    Clarke, Heidi; Brown, Timothy; Hu, Jianjun; Ganguli, Raj; Reed, Amber; Voevodin, Andrey; Shamberger, Patrick J.

    2016-10-01

    Variability remains the principal concern for commercialization of HfO2 based resistance switching devices. Here, we investigate the role of thermal processing conditions on internal structure of atomic layer deposited HfO2 thin films, and the impact of that structure on filament forming kinetics of p+ Si/HfO2/Cu and TiN/HfO2/Cu devices. Regardless of bias polarity or electrode metal, filament formation times are at least one order of magnitude shorter in polycrystalline than in amorphous films, which we attribute to the presence of fast ion migration along grain boundaries. Within polycrystalline films, filament formation times are correlated with degree of crystalline orientation. Inter-device variability in forming time is roughly equivalent across HfO2 film processing conditions. The kinetics of filament forming are shown to be highly dependent on HfO2 microstructure, with possible implications for the inter-device variability of subsequent switching cycles.

  17. Ion migration in crystalline and amorphous HfOX

    NASA Astrophysics Data System (ADS)

    Schie, Marcel; Müller, Michael P.; Salinga, Martin; Waser, Rainer; De Souza, Roger A.

    2017-03-01

    The migration of ions in HfOx was investigated by means of large-scale, classical molecular-dynamics simulations over the temperature range 1000 ≤T /K ≤2000 . Amorphous HfOx was studied in both stoichiometric and oxygen-deficient forms (i.e., with x = 2 and x = 1.9875); oxygen-deficient cubic and monoclinic phases were also studied. The mean square displacement of oxygen ions was found to evolve linearly as a function of time for the crystalline phases, as expected, but displayed significant negative deviations from linear behavior for the amorphous phases, that is, the behavior was sub-diffusive. That oxygen-ion migration was observed for the stoichiometric amorphous phase argues strongly against applying the traditional model of vacancy-mediated migration in crystals to amorphous HfO2. In addition, cation migration, whilst not observed for the crystalline phases (as no cation defects were present), was observed for both amorphous phases. In order to obtain activation enthalpies of migration, the residence times of the migrating ions were analyzed. The analysis reveals four activation enthalpies for the two amorphous phases: 0.29 eV, 0.46 eV, and 0.66 eV (values very close to those obtained for the monoclinic structure) plus a higher enthalpy of at least 0.85 eV. In comparison, the cubic phase is characterized by a single value of 0.43 eV. Simple kinetic Monte Carlo simulations suggest that the sub-diffusive behavior arises from nanoscale confinement of the migrating ions.

  18. Coalescence of silver clusters by immersion in diluted HF solution

    SciTech Connect

    Milazzo, R. G.; Mio, A. M.; D’Arrigo, G.; Spinella, C.; Grimaldi, M. G.; Rimini, E.

    2015-07-14

    The galvanic displacement deposition of silver on H-terminated Si (100) in the time scale of seconds is instantaneous and characterized by a cluster density of 10{sup 11}-10{sup 12} cm{sup −2}. The amount of deposited Ag follows a t{sup 1/2} dependence in agreement with a Cottrell diffusion limited mechanism. At the same time, during the deposition, the cluster density reduces by a factor 5. This behavior is in contrast with the assumption of immobile clusters. We show in the present work that coalescence and aggregation occur also in the samples immersed in the diluted hydrofluoric acid (HF) solution without the presence of Ag{sup +}. Clusters agglomerate according to a process of dynamic coalescence, typical of colloids, followed by atomic redistribution at the contact regions with the generation of multiple internal twins and stacking-faults. The normalized size distributions in terms of r/r{sub mean} follow also the prediction of the Smoluchowski ripening mechanism. No variation of the cluster density occurs for samples immersed in pure H{sub 2}O solution. The different behavior might be associated to the strong attraction of clusters to oxide-terminated Si surface in presence of water. The silver clusters are instead weakly bound to hydrophobic H-terminated Si in presence of HF. HF causes then the detachment of clusters and a random movement on the silicon surface with mobility of about 10{sup −13} cm{sup 2}/s. Attractive interaction (probably van der Waals) among particles promotes coarsening.

  19. TEA HF laser with a high specific radiation energy

    NASA Astrophysics Data System (ADS)

    Puchikin, A. V.; Andreev, M. V.; Losev, V. F.; Panchenko, Yu. N.

    2017-01-01

    Results of experimental studies of the chemical HF laser with a non-chain reaction are presented. The possibility of the total laser efficiency of 5 % is shown when a traditional C-to-C pumping circuit with the charging voltage of 20-24 kV is used. It is experimentally shown that the specific radiation output energy of 21 J/l is reached at the specific pump energy of 350 J/l in SF6/H2 = 14/1 mixture at the total pressure of 0.27 bar.

  20. Meteorite zircon constraints on the bulk Lu-Hf isotope composition and early differentiation of the Earth.

    PubMed

    Iizuka, Tsuyoshi; Yamaguchi, Takao; Hibiya, Yuki; Amelin, Yuri

    2015-04-28

    Knowledge of planetary differentiation is crucial for understanding the chemical and thermal evolution of terrestrial planets. The (176)Lu-(176)Hf radioactive decay system has been widely used to constrain the timescales and mechanisms of silicate differentiation on Earth, but the data interpretation requires accurate estimation of Hf isotope evolution of the bulk Earth. Because both Lu and Hf are refractory lithophile elements, the isotope evolution can be potentially extrapolated from the present-day (176)Hf/(177)Hf and (176)Lu/(177)Hf in undifferentiated chondrite meteorites. However, these ratios in chondrites are highly variable due to the metamorphic redistribution of Lu and Hf, making it difficult to ascertain the correct reference values for the bulk Earth. In addition, it has been proposed that chondrites contain excess (176)Hf due to the accelerated decay of (176)Lu resulting from photoexcitation to a short-lived isomer. If so, the paradigm of a chondritic Earth would be invalid for the Lu-Hf system. Herein we report the first, to our knowledge, high-precision Lu-Hf isotope analysis of meteorite crystalline zircon, a mineral that is resistant to metamorphism and has low Lu/Hf. We use the meteorite zircon data to define the Solar System initial (176)Hf/(177)Hf (0.279781 ± 0.000018) and further to identify pristine chondrites that contain no excess (176)Hf and accurately represent the Lu-Hf system of the bulk Earth ((176)Hf/(177)Hf = 0.282793 ± 0.000011; (176)Lu/(177)Hf = 0.0338 ± 0.0001). Our results provide firm evidence that the most primitive Hf in terrestrial zircon reflects the development of a chemically enriched silicate reservoir on Earth as far back as 4.5 billion years ago.

  1. Meteorite zircon constraints on the bulk Lu−Hf isotope composition and early differentiation of the Earth

    PubMed Central

    Iizuka, Tsuyoshi; Yamaguchi, Takao; Hibiya, Yuki; Amelin, Yuri

    2015-01-01

    Knowledge of planetary differentiation is crucial for understanding the chemical and thermal evolution of terrestrial planets. The 176Lu−176Hf radioactive decay system has been widely used to constrain the timescales and mechanisms of silicate differentiation on Earth, but the data interpretation requires accurate estimation of Hf isotope evolution of the bulk Earth. Because both Lu and Hf are refractory lithophile elements, the isotope evolution can be potentially extrapolated from the present-day 176Hf/177Hf and 176Lu/177Hf in undifferentiated chondrite meteorites. However, these ratios in chondrites are highly variable due to the metamorphic redistribution of Lu and Hf, making it difficult to ascertain the correct reference values for the bulk Earth. In addition, it has been proposed that chondrites contain excess 176Hf due to the accelerated decay of 176Lu resulting from photoexcitation to a short-lived isomer. If so, the paradigm of a chondritic Earth would be invalid for the Lu−Hf system. Herein we report the first, to our knowledge, high-precision Lu−Hf isotope analysis of meteorite crystalline zircon, a mineral that is resistant to metamorphism and has low Lu/Hf. We use the meteorite zircon data to define the Solar System initial 176Hf/177Hf (0.279781 ± 0.000018) and further to identify pristine chondrites that contain no excess 176Hf and accurately represent the Lu−Hf system of the bulk Earth (176Hf/177Hf = 0.282793 ± 0.000011; 176Lu/177Hf = 0.0338 ± 0.0001). Our results provide firm evidence that the most primitive Hf in terrestrial zircon reflects the development of a chemically enriched silicate reservoir on Earth as far back as 4.5 billion years ago. PMID:25870298

  2. Acute Pancreatitis and Pregnancy

    MedlinePlus

    ... Pancreatitis Acute Pancreatitis and Pregnancy Acute Pancreatitis and Pregnancy Timothy Gardner, MD Acute pancreatitis is defined as ... pancreatitis in pregnancy. Reasons for Acute Pancreatitis and Pregnancy While acute pancreatitis is responsible for almost 1 ...

  3. Prognostic biomarkers in acute coronary syndrome

    PubMed Central

    Pavan, Chiara

    2016-01-01

    The acute coronary syndrome (ACS) is a leading cause of death around the globe. Beside a still high mortality rate, additional complications of ACS include arrhythmias, left ventricular mural thrombus, cardiac fibrosis, heart failure (HF), cardiogenic shock, mitral valve dysfunction, aneurysms, up to cardiac rupture. Despite many prognostic tools have been developed over the past decades, efforts are still ongoing to identify reliable and predictive biomarkers, which may help predict the prognosis of these patients and especially the risk of HF. Recent evidence suggests that the value of a discrete number of biomarkers of myocardial fibrosis, namely the soluble form of suppression of tumorigenicity 2 (sST2) and galectin-3 (GAL-3), may be predictive of HF and death in patients with ACS. Interestingly, the already promising predictive value of these biomarkers when measured alone was shown to be consistently magnified when combined with other and well-established cardiac biomarkers such natriuretic peptides and cardiac troponins. This article is hence aimed to review the current knowledge about cardiac biomarkers of fibrosis and adverse remodeling. PMID:27500159

  4. Multiple spectrum analysis and evaluation for optical constants of HfO2 thin films

    NASA Astrophysics Data System (ADS)

    Liu, Dandan; Liu, Huasong; Jiang, Chenghui; Jiang, Yugang; Wang, Lishuan; Zhao, Zhihong; Ji, Yiqin

    2014-08-01

    HfO2 thin films were deposited on ZS1 silica by Ion Beam Sputtering (IBS) technique. Optical constants of HfO2 thin films were obtained by multiple spectrum analysis method, which combined the transmittance spectrum and ellipsometry spectrum of the film. The refractive index and extinction coiefficient of HfO2 thin films were evaluated by etching experiments of the film. The analysis spectral range was between 250nm and 850nm.

  5. Simultaneous measurements of HF-enhanced plasma waves and artificial field-aligned irregularities at Arecibo

    SciTech Connect

    Noble, S.T. ); Djuth, F.T. )

    1990-09-01

    Two radar systems with beams intersecting in the HF-modified F region were used to simultaneously measure HF-enhanced plasma lines (HFPLs) and artificial geomagnetic field-aligned irregularities (AFAIs). The Arecibo 430-MHz radar was used for the HFPL observations, and a portable 49.92-MHz backscatter radar was deployed on the island of Guadeloupe to monitor the AFAIs. The experiment was desgined to examine the degree to which HF-induced plasma turbulence influences the development of AFAIs. When the HF beam is stepped up in power, sustained HFPLs and AFAIs are first observed at the same HF power level, indicating that ponderomotively driven instabilities may be involved in the early time development of AFAIs. As the HF power is increased, the HFPL backscatter power begins to saturate at {approximately}70 MW effective radiated power (ERP). However, the backscatter from AFAIs is linearly dependent on HF power, even at the highest (120 MW ERP) HF power levels available at Arecibo. This suggests that additional processes may contribute to the development of AFAIs. For example, ponderomotively driven instabilities may give rise to weak geomagnetic field-aligned irregularities that are subsequently driven unstable by processes excited near the upper hybrid resonance. It is also likely that AFAIs greatly impact the development of HF-induced plasma turbulence at late times (>1 s) following HF turn-on. Once the ionosphere is preconditioned by high-power HF modifications, AFAIs and HFPLs can be simultaneously sustained at a much lower HF power level than that needed to originally excite them. The nature of the preconditioning process is currently not well understood. New theoretical initiatives are clearly needed to guide future experimental activity in this area.

  6. Evaluation of 25-Percent ATJ Fuel Blends in the John Deere 4045HF 280 Engine

    DTIC Science & Technology

    2014-08-01

    UNCLASSIFIED UNCLASSIFIED EVALUATION OF 25-PERCENT ATJ FUEL BLENDS IN THE JOHN DEERE 4045HF280 ENGINE INTERIM REPORT TFLRF No. 458...FUEL BLENDS IN THE JOHN DEERE 4045HF280 ENGINE INTERIM REPORT TFLRF No. 458 by Adam C. Brandt Edwin A. Frame U.S. Army TARDEC Fuels and...Fuel Blends in the John Deere 4045HF280 Engine 5a. CONTRACT NUMBER W56HZV-09-C-0100 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6

  7. Studies of Plasma Instability Processes Excited by Ground Based High Power HF ("Heating") Facilities

    DTIC Science & Technology

    2001-04-01

    by ground based high power HF (’ heating ’) facilities 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT NUMBER Dr. Alexander...Prescribed by ANSI Std. Z39-18 Grant SPC 00-4010 Final Report STUDIES OF PLASMA INSTABILITY PROCESSES EXCITED BY GROUND BASED HIGH POWER HF (" HEATING ...growing field of ionospheric HF heating . The main new results can be summarized as following: 1. Two sets of observations of suprathermal electrons

  8. Enhanced resistive switching and multilevel behavior in bilayered HfAlO/HfAlO{sub x} structures for non-volatile memory applications

    SciTech Connect

    Faita, F. L.; Silva, J. P. B.; Pereira, M.; Gomes, M. J. M.

    2015-12-14

    In this work, hafnium aluminum oxide (HfAlO) thin films were deposited by ion beam sputtering deposition technique on Si substrate. The presence of oxygen vacancies in the HfAlO{sub x} layer deposited in oxygen deficient environment is evidenced from the photoluminescence spectra. Furthermore, HfAlO(oxygen rich)/HfAlO{sub x}(oxygen poor) bilayer structures exhibit multilevel resistive switching (RS), and the switching ratio becomes more prominent with increasing the HfAlO layer thickness. The bilayer structure with HfAlO/HfAlO{sub x} thickness of 30/40 nm displays the enhanced multilevel resistive switching characteristics, where the high resistance state/intermediate resistance state (IRS) and IRS/low resistance state resistance ratios are ≈10{sup 2} and ≈5 × 10{sup 5}, respectively. The switching mechanisms in the bilayer structures were investigated by the temperature dependence of the three resistance states. This study revealed that the multilevel RS is attributed to the coupling of ionic conduction and the metallic conduction, being the first associated to the formation and rupture of conductive filaments related to oxygen vacancies and the second with the formation of a metallic filament. Moreover, the bilayer structures exhibit good endurance and stability in time.

  9. Clinical trials update from the European Society of Cardiology-Heart Failure meeting 2015: AUGMENT-HF, TITRATION, STOP-HF, HARMONIZE, LION HEART, MOOD-HF, and renin-angiotensin inhibitors in patients with heart and renal failure.

    PubMed

    Pellicori, Pierpaolo; Clark, Andrew L

    2015-09-01

    This article provides an overview on the key trials relevant to the pathophysiology, prevention, and treatment of heart failure (HF) presented at the Heart Failure Association (HFA) of the European Society of Cardiology (ESC) annual meeting held in Seville, Spain in May 2015. Trials reported include AUGMENT-AF (myocardial injections of calcium-alginate hydrogel), a propensity score-matched study of renin-angiotensin system antagonists in patients with HF and severe renal dysfunction, HARMONIZE (sodium zirconium cyclosilicate used to bind potassium), TITRATION, comparing two regimes for introducing LCZ696, STOP-HF, a trial of intramyocardial stromal cell-derived factor-1, MOOD-HF (escitalopram for patients with heart failure and depression), and LION HEART, a trial of intermittent levosimendan therapy. Unpublished reports should be considered as preliminary, since analyses may change in the final publication.

  10. Characteristics, Diagnosis and Prognosis of Acute-on-Chronic Liver Failure in Cirrhosis Associated to Hepatitis B.

    PubMed Central

    Li, Hai; Chen, Liu-Ying; Zhang, Nan-nan; Li, Shu-Ting; Zeng, Bo; Pavesi, Marco; Amorós, Àlex; Mookerjee, Rajeshwar P; Xia, Qian; Xue, Feng; Ma, Xiong; Hua, Jing; Sheng, Li; Qiu, De-kai; Xie, Qing; Foster, Graham R; Dusheiko, Geoffrey; Moreau, Richard; Gines, Pere; Arroyo, Vicente; Jalan, Rajiv

    2016-01-01

    The diagnostic and prognostic criteria of acute-on-chronic liver failure (ACLF) were developed in patients with no Hepatitis B virus (HBV) cirrhosis (CANONIC study). The aims of this study were to evaluate whether the diagnostic (CLIF-C organ failure score; CLIF-C OFs) criteria can be used to classify patients; and the prognostic score (CLIF-C ACLF score) could be used to provide prognostic information in HBV cirrhotic patients with ACLF. 890 HBV associated cirrhotic patients with acute decompensation (AD) were enrolled. Using the CLIF-C OFs, 33.7% (300 patients) were diagnosed as ACLF. ACLF was more common in the younger patients and in those with no previous history of decompensation. The most common organ failures were ‘hepatic’ and ‘coagulation’. As in the CANONIC study, 90-day mortality was extremely low in the non-ACLF patients compared with ACLF patients (4.6% vs 50%, p < 0.0001). ACLF grade and white cell count, were independent predictors of mortality. CLIF-C ACLFs accurately predicted short-term mortality, significantly better than the MELDs and a disease specific score generated for the HBV patients. Current study indicates that ACLF is a clinically and pathophysiology distinct even in HBV patients. Consequently, diagnostic criteria, prognostic scores and probably the management of ACLF should base on similar principles. PMID:27146801

  11. Efficient noble metal nanocatalysts supported on HfC(001) for O2 dissociation

    NASA Astrophysics Data System (ADS)

    Wang, Shiyan; Zhang, Xilin; Zhang, Yanxing; Mao, Jianjun; Yang, Zongxian

    2017-03-01

    The adsorption and dissociation of O2 on the M4 (M=Au, Pd, Pt) clusters supported on HfC(001) (Hafnium Carbide) are investigated using ab initio density functional theory calculations. The geometric and electronic structures are analyzed in detail. It is found that the dissociation barriers of O2 on Au4/HfC(001) (0.26 eV), Pd4/HfC(001) (0.49 eV) and Pt4/HfC(001) (0.09 eV) are much smaller than those on the clean surfaces of HfC(001) (1.60 eV), Au(111) (1.37 eV), Pd(111) (1.0 and 0.91 eV) and Pt(111) (0.27-0.7 eV), respectively. The low dissociation barriers imply that the Pt4/HfC(001) exhibits the highest catalytic activity for O2 dissociation, and the Au4/HfC(001) and Pd4/HfC(001) may also be possible substitutes with lower cost for the current Pt/C catalyst for O2 dissociation. The present study is conductive to designing new efficient noble metal catalyst using HfC support for efficiently promoting O2 dissociation.

  12. Optical cavity temperature measurement based on the first overtones spontaneous emission spectra for HF chemical laser

    NASA Astrophysics Data System (ADS)

    Tang, Shukai; Li, Liucheng; Duo, Liping; Wang, Yuanhu; Yu, Haijun; Jin, Yuqi; Sang, Fengting

    2015-02-01

    An optical cavity temperature test method has been established for the HF chemical laser. This method assumes that in HF optical cavity the rotational distribution of vibrationally excited HF molecules meets the statistical thermodynamic distribution, the first overtones (v = 3-1 and 2-0) spontaneous emission spectral intensity distribution is obtained by using OMA V, the optical cavity temperature is calculated by linear fitting the rotational thermal equilibrium distribution formula for each HF vibrationally excited state. This method is simple, reliable, and repeatable. This method can be used to test the optical cavity temperature not only without lasing, but also with lasing.

  13. Lu-Hf total-rock age for the Amitsoq gneisses, West Greenland

    NASA Technical Reports Server (NTRS)

    Pettingill, H. S.; Patchett, P. J.

    1981-01-01

    Lu-Hf total-rock data for the Amitsoq gneisses of West Greenland yield an age of 3.55 + or - 0.22 billion years, based on the decay constant for Lu-176 of 1.96 x 10 to the -11th/year, and an initial Hf-176/Hf-177 ratio of 0.280482 + or - 33. The result is in good agreement with Rb-Sr total-rock and U-Pb zircon ages. In spite of severe metamorphism of the area at 2.9 billion years, zircons from two of the samples have remained on the total-rock line, and define points close to the initial Hf ratio. The initial Hf-176/Hf-177 lies close to a chondritic Hf isotopic evolution curve from 4.55 billion years to present. This is consistent with the igneous precursors to the Amitsoq gneisses having been derived from the mantle at or shortly before 3.6 billion years. Anomalous relationships between Hf concentration and the Lu-176/Hf-177 ratio may suggest that trace element abundances in the Amitsoq gneisses are partly controlled by processes related to metamorphism.

  14. Lu-hf total-rock isochron for the eucrite meteorites

    USGS Publications Warehouse

    Patchett, P.J.; Tatsumoto, M.

    1980-01-01

    The isotope 176Lu (2.6% of natural lutetium) decays by ??- to 176Hf, with a long half life. We present here the first Lu-Hf isochron. The eucrite meteorites, a suite of planetary igneous rocks of known age, 4,550 Myr, define a 10-point total-rock isochron with a slope of 0.0934 ?? 40, leading to a value of 3.53 ?? 0.14 ??1010yr for the ??--decay half life of 176Lu. The isochron intercept of 0.27973 ?? 12 gives the initial 176Hf/177Hf for the inner Solar System at the time of accretion. ?? 1980 Nature Publishing Group.

  15. Importance of the Lu-Hf isotopic system in studies of planetary chronology and chemical evolution

    NASA Technical Reports Server (NTRS)

    Patchett, P. J.

    1983-01-01

    The Lu-176-Hf-176 isotope method and its applications in earth sciences are discussed with regard to planetary-evolution studies. From new data on basalts from oceanic islands, Hf-176/Hf-177 and Nd-143/Nd-144 are found to display a single linear isotopic variation in the suboceanic mantle, whereas considerable divergences occur in Hf-176/Hf-177-Sr-87/Sr-86 and Nd-143/Nd-144-Sr87/Sr-86 diagrams. With the acquisition of further Hf-Sr-Nd isotopic data, these discordant Sr-87/Sr-86 relationships may allow a distinction between processes such as mantle metasomatism, influence of sea-water altered material in the magma source, or recycling of sediments into the mantle. The best quality Hf isotope data are obtained from granitoid or zircons, and are most suitable for studying ancient terrestrial Hf isotopic variations. Lu-Hf is shown to be a viable method for dating ancient terrestrial and extraterrestrial samples, but is unlikely to find wide application in pure chronological studies because it offers little advantage over existing methods.

  16. Ferroelectric phase stabilization of HfO2 by nitrogen doping

    NASA Astrophysics Data System (ADS)

    Xu, Lun; Nishimura, Tomonori; Shibayama, Shigehisa; Yajima, Takeaki; Migita, Shinji; Toriumi, Akira

    2016-09-01

    We report that nitrogen (N) doping can drive the ferroelectricity of HfO2. It was found that N doping can cause the transition from a monoclinic phase to a highly symmetric phase. The role of N doping is discussed from the viewpoints of charge balance and bond-constraining effects. The former is responsible for the structural transformation from a paraelectric phase to a ferroelectric phase by forming an oxygen vacancy. In addition, Hf-N and N-O bonds with covalent characteristics have strong effects on HfO2 structural and electrical properties, and thus contribute to a marked HfO2 para-/ferroelectric transition.

  17. The use of anhydrous HF solvolysis in conversion of biomass to glucose

    NASA Astrophysics Data System (ADS)

    Mort, A.; Parker, S.

    1982-12-01

    Anhydrous hydrogen fluoride solubilizes and deploymerizes crystalline cellulose, cellulose imbedded in lignin, and amorphous polysaccharides in less than 15 minutes at temperatures as low as 0 C. It is suggested that this reaction may be used to convert crude cellulosic biomass materials into sugar monomers suitable for microbial fermentation. No degradation of the sugars during the HF-catalyzed deploymerization is noted. Because the HF is very volatile it is easily removed from the reaction for reuse with more biomass. The characterization of this reaction and the many advantages of HF solvolysis over acid and enzymatic hydrolysis are examined. Some of the special problems associated with HF are discussed.

  18. [Medico-economic impact of an innovative management of CHF by HF unit].

    PubMed

    Baudouin, C; Groshens, S; Gueneau, P; Rousseau, M; Saura, M; Hryschyschyn, N; Hillani, A; Dagorn, J; Pitthan, E; Jourdain, P

    2015-11-01

    Chronic heart failure remains a frequent, severe and costly disease. Despite encouraging data from different countries, heart failure clinics are scarce in France. We have analyzed the impact of a heart failure clinic (UTIC of Pontoise) in terms of reduction of rehospitalizations and in hospitalization costs in 4855 consecutive patients. In our study, heart failure clinic management dramatically reduces HF related hospitalizations (RRR: -28 %, P=0.001) and HF related costs (55% reduction, P<0.001) regardless of comorbidities or disease severity. HF clinics have to be developed in France in order to optimize management of CHF and reduce the HF related costs.

  19. Hf isotope compositions of U.S. Geological Survey reference materials

    NASA Astrophysics Data System (ADS)

    Weis, Dominique; Kieffer, Bruno; Hanano, Diane; Nobre Silva, Inês; Barling, Jane; Pretorius, Wilma; Maerschalk, Claude; Mattielli, Nadine

    2007-06-01

    A systematic multi-isotopic and trace element characterization of U.S. Geological Survey reference materials has been carried out at the Pacific Centre for Isotopic and Geochemical Research, University of British Columbia. Values of 176Hf/177Hf are recommended for the following reference materials (mean ±2 SD): G-2: 0.282523 ± 6; G-3: 0.282518 ± 1; GSP-2: 0.281949 ± 8; RGM-1: 0.283017 ± 13; STM-1: 0.283019 ± 12; STM-2: 0.283021 ± 5; BCR-1: 0.282875 ± 8; BCR-2: 0.282870 ± 8; BHVO-1: 0.283106 ± 12; BHVO-2: 0.283105 ± 11; AGV-1: 0.282979 ± 6; and AGV-2: 0.282984 ± 9. Reproducibility is better than 50 ppm for the granitoid compositions and better than 40 ppm for the basaltic/andesitic compositions. For the isotopic analyses acquired early in this project on glass columns, Hf isotopic analyses from several of the reference materials were significantly less reproducible than Nd and Sr isotopic analyses determined from the same sample dissolution. The 176Hf/177Hf ratios for relatively radiogenic compositions (BCR-1, 2; BHVO-1, 2; RGM-1) were shifted systematically toward lower values by 100-150 ppm when a borosilicate primary column was used. Although systematic, the shift for felsic compositions was generally within analytical error, except for GSP-2, which has a very low Hf isotopic ratio, where the shift was to higher 176Hf/177Hf. Trace element and isotopic characterization of the borosilicate glass column, borosilicate frits, and quartz columns reveals extremely variable levels of trace elements. The 176Hf/177Hf ratios for these materials are very unradiogenic (borosilicate glass <0.28220 frit = 0.28193 ± 4). The borosilicate frit material appears to be the most variable in elemental concentration and isotopic composition. The quartz material has very low levels (Hf/177Hf and high Hf concentrations of the borosilicate glass column (16 ppm) and frit material (22 ppm) indicate that only small amounts of such unradiogenic

  20. Structural degradation of thin HfO2 film on Ge during the postdeposition annealing

    NASA Astrophysics Data System (ADS)

    Miyata, Noriyuki; Yasuda, Tetsuji; Abe, Yasuhiro

    2010-05-01

    Securing the thermal robustness of thin hafnium oxide (HfO2) film on the semiconductor surface is an important technical issue in the fabrication of the metal-oxide-semiconductor field-effect transistor devices, as the HfO2-based high-k gate stacks usually undergo high-temperature processes. In this study, the structural development of thin HfO2 film on a Ge surface during postdeposition annealing in an ultrahigh vacuum was examined to explore the origin for the initial degradation of thin HfO2 film. Void nucleation and subsequent two-dimensional void growth take place at 780-840 °C, while the chemical composition of the remaining Hf oxide is virtually stable. Both the void nucleation and growth processes show similar larger activation energy of about 10 eV. Based on the observed manner of void growth and the estimated activation energies, the authors propose that mass transport on the HfO2 surface is responsible for void nucleation in the HfO2 films on Ge. The authors also compare the present results with the previous studies on HfO2/Si structures, and suggest that similar surface process leads to the local Hf silicidation.

  1. Anticooperativity of FHF hydrogen bonds in clusters of the type F- × (HF)n, RF × (HF)n and XF × (HF)n, R = alkyl and X = H, Br, Cl, F

    NASA Astrophysics Data System (ADS)

    Kucherov, S. Yu.; Bureiko, S. F.; Denisov, G. S.

    2016-02-01

    Properties of twenty five hydrogen-bonded complexes, namely, F- × (HF)n (n = 1-6), RF × (HF)n (R = t-Bu, i-Pr, Et, Me; n = 1-3), XF × (HF)n (X = H, Br, Cl; n = 1-2), and FF…HF with the hydrogen bond energy varying in a wide range have been calculated using ab initio methods at the MP2/6-31++G** level. For the first time, the energies, geometrical parameters and vibrational frequencies are obtained for the series of clusters, where the bonding character changes from covalent to van der Waals on the variation of proton-acceptor ability of the base, and the energies are in the range of 45-1 kcal/mol. The mutual influence of multiple hydrogen bonds of F…HF type in clusters, in which a fluorine anion or an atom participates in hydrogen bond formation as the acceptor, is systematically investigated. The relative changes in the values of the considered parameters on the sequential addition of an HF molecule (anticooperativity) were determined. It was shown that non-additivity of the interaction is most strongly pronounced in the energy and vibrational frequency values, geometrical parameters of hydrogen bonds are less sensitive to the mutual influence. The anticooperative effect is more pronounced on the hydrogen bridge length R(F...F) than on the geometry of proton donor r(HF). The hydrogen bond formation and the increase of the number n of ligands lead to successive lengthening of the r(XF) bond adjacent to the hydrogen bridge. The length of an XF bond changes stronger on formation of each hydrogen bond than the HF bond length.

  2. Distribution of p-process 174Hf in early solar system materials and the origin of nucleosynthetic Hf and W isotope anomalies in Ca-Al rich inclusions

    NASA Astrophysics Data System (ADS)

    Peters, Stefan T. M.; Münker, Carsten; Pfeifer, Markus; Elfers, Bo-Magnus; Sprung, Peter

    2017-02-01

    Some nuclides that were produced in supernovae are heterogeneously distributed between different meteoritic materials. In some cases these heterogeneities have been interpreted as the result of interaction between ejecta from a nearby supernova and the nascent solar system. Particularly in the case of the oldest objects that formed in the solar system - Ca-Al rich inclusions (CAIs) - this view is confirm the hypothesis that a nearby supernova event facilitated or even triggered solar system formation. We present Hf isotope data for bulk meteorites, terrestrial materials and CAIs, for the first time including the low-abundance isotope 174Hf (∼0.16%). This rare isotope was likely produced during explosive O/Ne shell burning in massive stars (i.e., the classical "p-process"), and therefore its abundance potentially provides a sensitive tracer for putative heterogeneities within the solar system that were introduced by supernova ejecta. For CAIs and one LL chondrite, also complementary W isotope data are reported for the same sample cuts. Once corrected for small neutron capture effects, different chondrite groups, eucrites, a silicate inclusion of a IAB iron meteorite, and terrestrial materials display homogeneous Hf isotope compositions including 174Hf. Hafnium-174 was thus uniformly distributed in the inner solar system when planetesimals formed at the <50 ppm level. This finding is in good agreement with the evidently homogeneous distributions of p-process isotopes 180W, 184Os and possibly 190Pt between different iron meteorite groups. In contrast to bulk meteorite samples, CAIs show variable depletions in p-process 174Hf with respect to the inner solar system composition, and also variable r-process (or s-process) Hf and W contributions. Based on combined Hf and W isotope compositions, we show that CAIs sampled at least one component in which the proportion of r- and s-process derived Hf and W deviates from that of supernova ejecta. The Hf and W isotope

  3. Observations of HF backscatter decay rates from HAARP generated FAI

    NASA Astrophysics Data System (ADS)

    Bristow, William; Hysell, David

    2016-07-01

    Suitable experiments at the High-frequency Active Auroral Research Program (HAARP) facilities in Gakona, Alaska, create a region of ionospheric Field-Aligned Irregularities (FAI) that produces strong radar backscatter observed by the SuperDARN radar on Kodiak Island, Alaska. Creation of FAI in HF ionospheric modification experiments has been studied by a number of authors who have developed a rich theoretical background. The decay of the irregularities, however, has not been so widely studied yet it has the potential for providing estimates of the parameters of natural irregularity diffusion, which are difficult measure by other means. Hysell, et al. [1996] demonstrated using the decay of radar scatter above the Sura heating facility to estimate irregularity diffusion. A large database of radar backscatter from HAARP generated FAI has been collected over the years. Experiments often cycled the heater power on and off in a way that allowed estimates of the FAI decay rate. The database has been examined to extract decay time estimates and diffusion rates over a range of ionospheric conditions. This presentation will summarize the database and the estimated diffusion rates, and will discuss the potential for targeted experiments for aeronomy measurements. Hysell, D. L., M. C. Kelley, Y. M. Yampolski, V. S. Beley, A. V. Koloskov, P. V. Ponomarenko, and O. F. Tyrnov, HF radar observations of decaying artificial field aligned irregularities, J. Geophys. Res. , 101, 26,981, 1996.

  4. Radiation effects in Zr and Hf containing garnets

    NASA Astrophysics Data System (ADS)

    Whittle, Karl R.; Blackford, Mark G.; Smith, Katherine L.; Zaluzec, Nestor J.; Weyland, Matthew; Lumpkin, Gregory R.

    2015-07-01

    Garnets have been considered as host phases for the safe immobilisation of high-level nuclear waste, as they have been shown to accommodate a wide range of elements across three different cation sites, such as Ca, Y, Mn on the a-site, Fe, Al, U, Zr, and Ti on the b-site, and Si, Fe, Al on the c-site. Garnets, due to their ability to have variable composition, make ideal model materials for the examination of radiation damage and recovery in nuclear materials, including as potential waste forms. Kimzeyite, Ca3Zr2FeAlSiO12, has been shown naturally to contain up to 30 wt% Zr, and has previously been examined to elucidate both the structure and ordering within the lattice. This study examines the effects of radiation damage and recovery using in-situ ion beam irradiation with 1 MeV Kr ions at the IVEM-TANDEM facility, Argonne National Laboratory. The complementary Hf containing system Ca3Hf2FeAlSiO12 was also examined, and found to have a different response to irradiation damage. A sample of irradiated Ca3Zr2FeAlSiO12, at 1000 K, was characterised using aberration corrected (S)TEM and found to contain discreet, nano-sized, crystalline Fe rich particles, indicating a competing process during recovery is occurring.

  5. Chemistry of H2O and HF Under Extreme Conditions

    SciTech Connect

    Fried, L; Goldman, N; Kuo, I W; Mundy, C

    2005-11-28

    The predicted high pressure superionic phases of water and HF are investigated via ab initio molecular dynamics. These phases could potentially be achieved through either static compression with heating or through shock compression. We study water at densities of 2.0-3.0 g/cc (34-115 GPa) along the 2000K isotherm.We find that extremely rapid (superionic) diffusion of protons occurs in a fluid phase at pressures between 34 and 58 GPa. A transition to a stable body-centered cubic (bcc) O lattice with superionic proton conductivity is observed between 70 and 75 GPa, a much higher pressure than suggested in prior work. We find that all molecular species at pressures greater than 75 GPa are too short lived to be classified as bound states. Up to 95 GPa, we find a solid superionic phase characterized by covalent O-H bonding. Above 95 GPa, a transient network phase is found characterized by symmetric O-H hydrogen bonding with nearly 50% covalent character. Ab initio molecular dynamics simulations of HF were conducted at densities of 1.8-4.0 g/cc along the 900 K isotherm. According to our simulations, a unique form of (symmetric) hydrogen bonding could play a significant role in superionic conduction. Our work shows that superionic phases could be more prevalent in hydrogen bonded systems than previously thought, such as HCl and HBr.

  6. HF Radar Sea-echo from Shallow Water.

    PubMed

    Lipa, Belinda; Nyden, Bruce; Barrick, Don; Kohut, Josh

    2008-08-06

    HF radar systems are widely and routinely used for the measurement of ocean surface currents and waves. Analysis methods presently in use are based on the assumption of infinite water depth, and may therefore be inadequate close to shore where the radar echo is strongest. In this paper, we treat the situation when the radar echo is returned from ocean waves that interact with the ocean floor. Simulations are described which demonstrate the effect of shallow water on radar sea-echo. These are used to investigate limits on the existing theory and to define water depths at which shallow-water effects become significant. The second-order spectral energy increases relative to the first-order as the water depth decreases, resulting in spectral saturation when the waveheight exceeds a limit defined by the radar transmit frequency. This effect is particularly marked for lower radar transmit frequencies. The saturation limit on waveheight is less for shallow water. Shallow water affects second-order spectra (which gives wave information) far more than first-order (which gives information on current velocities), the latter being significantly affected only for the lowest radar transmit frequencies for extremely shallow water. We describe analysis of radar echo from shallow water measured by a Rutgers University HF radar system to give ocean wave spectral estimates. Radar-derived wave height, period and direction are compared with simultaneous shallow-water in-situ measurements.

  7. Difficulties encountered by general practitioners during acute behavioral disturbances of their dementia patients.

    PubMed

    Campana, Marion; Bonin-Guillaume, Sylvie; Yagoubi, Ramzi; Berbis, Julie; Franqui, Caroline

    2016-06-01

    Alzheimer diseases and related disorders (ADRD) remain a major public health issue. The progression of the disease is dominated by behavioral and psychological symptoms of dementia (BPSD) which are frequent and burdensome for caregivers. The aim of our survey was to study how the general practionner managed these behavioral disturbances (particularly agitation and aggressiveness) in community living patients with ADRD and support of their main caregivers. We based our study on a medical survey sent to all general practitioners (GP) practicing in four districts in Marseille near from a secure unit. Ninety five out of 260 answered to the survey and 57 had already been exposed to patients' behavioral decompensation. For these BPSD management, atypical neuroleptics and benzodiazepines were mostly prescribed, and according to the literature and guidelines. Half of the GP's recognized the weak effectiveness of this strategy. Almost all of them are interested in having a document summarizing the main strategy to be set up or a possibility to call a specialized mobile team with doctors and professionals caregivers. A few dedicated consultations were devoted to informal caregivers whereas GP were aware of negative effects of these decompensations on them. This study point out difficulties for GP to provide appropriate management for their patients with ADRD living at home and for their informal caregivers, particularly during acute behavioral disturbance, despite their practical knowledges.

  8. [Acute pancreatitis].

    PubMed

    Hecker, M; Mayer, K; Askevold, I; Collet, P; Weigand, M A; Krombach, G A; Padberg, W; Hecker, A

    2014-03-01

    Acute pancreatitis is a potentially fatal disease with individually differing expression of systemic involvement. For this reason early diagnosis with subsequent risk stratification is essential in the clinical management of this frequent gastroenterological disorder. Severe forms of acute pancreatitis occur in approximately 20 % of cases often requiring intensive care monitoring and interdisciplinary therapeutic approaches. In the acute phase adequate fluid replacement and sufficient analgesic therapy is of major therapeutic importance. Concerning the administration of antibiotics and the nutritional support of patients with acute pancreatitis a change in paradigms could be observed in recent years. Furthermore, endoscopic, radiological or surgical interventions can be necessary depending on the severity of the disease and potential complications.

  9. Bronchitis - acute

    MedlinePlus

    ... to breathe. Other symptoms of bronchitis are a cough and coughing up mucus. Acute means the symptoms ... diagnosed with chronic bronchitis, you must have a cough with mucus on most days for at least ...

  10. Acute Bronchitis

    MedlinePlus

    ... bronchitis? Acute bronchitis is inflammation of your bronchial tree. The bronchial tree consists of tubes that carry air into your ... weeks or months. This happens because the bronchial tree takes a while to heal. A lasting cough ...

  11. The role of Upper Hybrid Turbulence on HF Artificial Ionization

    NASA Astrophysics Data System (ADS)

    Papadopoulos, Konstantinos Dennis; Najmi, Amir; Eliasson, Bengt; Milikh, Gennady

    2016-07-01

    One of the most fascinating and scientifically interesting phenomena of active space experiments is the discovery of artificial ionization by Todd Pedersen when the HAARP ERP reached the GW level. The phenomenon has been well documented experimentally. A theoretical model based on ionization by energetic electrons accelerated by 50-100 V/m localized electric fields due to Strong Langmuir Turbulence (SLT) near the reflection surface of the HF pump wave, reproduced the observed dynamics of the descending plasma layer quite accurately. A major defect of the model was that the electron temperature in the SLT region was a free parameter. When taken as the 2000 K representing the ambient electron temperature the SLT driven electron flux was insufficient to produce ionization. An equivalent electron temperature of 5000 K or higher was necessary to reproduce the observations. The needed electron heating was attributed to the interaction of the HF at the Upper Hybrid (UH) resonant layer, approximately 5 Km below the reflection region where the HF electric field is perpendicular to the ambient magnetic field. The heated electrons expanded upwards along the magnetic field line and interacted with SLT fields near the resonance region. A consequence of this defect was that the theory could not explain the puzzling double resonance effect. Namely the observation that the ionization level was much stronger when the HF frequency and the UH resonance were a multiple of the electron cyclotron frequency. To remedy this we used a series of Vlasov simulations to explore the HF-plasma interaction in the vicinity of the UH resonance. The simulations followed the evolution of the spectral density of the electric field over a 7.5 MHz frequency band and cm scale lengths and of the electron distribution function over one millisecond for both double resonant and non-resonant cases. Many new features were revealed by the analysis of the simulations such as: 1. Broadening of the wave

  12. Electron Microprobe Analysis of Hf in Zircon: Suggestions for Improved Accuracy of a Difficult Measurement

    NASA Astrophysics Data System (ADS)

    Fournelle, J.; Hanchar, J. M.

    2013-12-01

    It is not commonly recognized as such, but the accurate measurement of Hf in zircon is not a trivial analytical issue. This is important to assess because Hf is often used as an internal standard for trace element analyses of zircon by LA-ICPMS. The issues pertaining to accuracy revolve around: (1) whether the Hf Ma or the La line is used; (2) what accelerating voltage is applied if Zr La is also measured, and (3) what standard for Hf is used. Weidenbach, et al.'s (2004) study of the 91500 zircon demonstrated the spread (in accuracy) of possible EPMA values for six EPMA labs, 2 of which used Hf Ma, 3 used Hf La, and one used Hf Lb, and standards ranged from HfO2, a ZrO2-HfO2 compound, Hf metal, and hafnon. Weidenbach, et al., used the ID-TIMS values as the correct value (0.695 wt.% Hf.), for which not one of the EPMA labs came close to that value (3 were low and 3 were high). Those data suggest: (1) that there is a systematic underestimation error of the 0.695 wt% Hf (ID-TIMS Hf) value if Hf Ma is used; most likely an issue with the matrix correction, as the analytical lines and absorption edges of Zr La, Si Ka and Hf Ma are rather tightly packed in the electromagnetic spectrum. Mass absorption coefficients are easily in error (e.g., Donovan's determination of the MAC of Hf by Si Ka of 5061 differs from the typically used Henke value of 5449 (Donovan et al, 2002); and (2) For utilization of the Hf La line, however, the second order Zr Ka line interferes with Hf La if the accelerating voltage is greater than 17.99 keV. If this higher keV is used and differential mode PHA is applied, only a portion of the interference is removed (e.g., removal of escape peaks), causing an overestimation of Hf content. Unfortunately, it is virtually impossible to apply an interference correction in this case, as it is impossible to locate Hf-free Zr probe standard. We have examined many of the combinations used by those six EPMA labs and concluded that the optimal EPMA is done with Hf

  13. What Hf isotopes in zircon tell us about crust-mantle evolution

    NASA Astrophysics Data System (ADS)

    Iizuka, Tsuyoshi; Yamaguchi, Takao; Itano, Keita; Hibiya, Yuki; Suzuki, Kazue

    2017-03-01

    The 176Lu-176Hf radioactive decay system has been widely used to study planetary crust-mantle differentiation. Of considerable utility in this regard is zircon, a resistant mineral that can be precisely dated by the U-Pb chronometer and record its initial Hf isotope composition due to having low Lu/Hf. Here we review zircon U-Pb age and Hf isotopic data mainly obtained over the last two decades and discuss their contributions to our current understanding of crust-mantle evolution, with emphasis on the Lu-Hf isotope composition of the bulk silicate Earth (BSE), early differentiation of the silicate Earth, and the evolution of the continental crust over geologic history. Meteorite zircon encapsulates the most primitive Hf isotope composition of our solar system, which was used to identify chondritic meteorites best representative of the BSE (176Hf/177Hf = 0.282793 ± 0.000011; 176Lu/177Hf = 0.0338 ± 0.0001). Hadean-Eoarchean detrital zircons yield highly unradiogenic Hf isotope compositions relative to the BSE, providing evidence for the development of a geochemically enriched silicate reservoir as early as 4.5 Ga. By combining the Hf and O isotope systematics, we propose that the early enriched silicate reservoir has resided at depth within the Earth rather than near the surface and may represent a fractionated residuum of a magma ocean underlying the proto-crust, like urKREEP beneath the anorthositic crust on the Moon. Detrital zircons from world major rivers potentially provide the most robust Hf isotope record of the preserved granitoid crust on a continental scale, whereas mafic rocks with various emplacement ages offer an opportunity to trace the Hf isotope evolution of juvenile continental crust (from εHf[4.5 Ga] = 0 to εHf[present] = + 13). The river zircon data as compared to the juvenile crust composition highlight that the supercontinent cycle has controlled the evolution of the continental crust by regulating the rates of crustal generation and intra

  14. Evolution of continental crust and mantle heterogeneity: Evidence from Hf isotopes

    USGS Publications Warehouse

    Jonathan, Patchett P.; Kouvo, O.; Hedge, C.E.; Tatsumoto, M.

    1982-01-01

    We present initial 176Hf/177 Hf ratios for many samples of continental crust 3.7-0.3 Gy old. Results are based chiefly on zircons (1% Hf) and whole rocks: zircons are shown to be reliable carriers of essentially the initial Hf itself when properly chosen on the basis of U-Pb studies. Pre-3.0 Gy gneisses were apparently derived from an unfractionated mantle, but both depleted and undepleted mantle are evident as magma sources from 2.9 Gy to present. This mantle was sampled mainly from major crustal growth episodes 2.8, 1.8 and 0.7 Gy ago, all of which show gross heterogeneity of 176Hf/177Hf in magma sources from ??Hf=0 to +14, or about 60% of the variability of the present mantle. The approximate ??Hf=2??Nd relationship in ancient and modern igneous rocks shows that 176Lu/177Hf fractionates in general twice as much as 147Sm/144Nd in mantle melting processes. This allows an estimation of the relative value of the unknown bulk solid/liquid distribution coefficient for Hf. DLu/DHf=??? 2.3 holds for most mantle source regions. For garnet to be an important residual mantle phase, it must hold Hf strongly in order to preserve Hf-Nd isotopic relationships. The ancient Hf initials are consistent with only a small proportion of recycled older cratons in new continental crust, and with quasi-continuous, episodic growth of the continental crust with time. However, recycling of crust less than 150 My old cannot realistically be detected using Hf initials. The mantle shows clearly the general positive ??Hf resulting from a residual geochemical state at least back to 2.9 Gy ago, and seems to have repeatedly possessed a similar degree of heterogeneity, rather than a continuously-developing depletion. This is consistent with a complex dynamic disequilibrium model for the creation, maintenance and destruction of heterogeneity in the mantle. ?? 1981 Springer-Verlag.

  15. Accurate Hf isotope determinations of complex zircons using the "laser ablation split stream" method

    NASA Astrophysics Data System (ADS)

    Fisher, Christopher M.; Vervoort, Jeffery D.; DuFrane, S. Andrew

    2014-01-01

    The "laser ablation split stream" (LASS) technique is a powerful tool for mineral-scale isotope analyses and in particular, for concurrent determination of age and Hf isotope composition of zircon. Because LASS utilizes two independent mass spectrometers, a large range of masses can be measured during a single ablation, and thus, the same sample volume can be analyzed for multiple geochemical systems. This paper describes a simple analytical setup using a laser ablation system coupled to a single-collector (for U-Pb age determination) and a multicollector (for Hf isotope analyses) inductively coupled plasma mass spectrometer (MC-ICPMS). The ability of the LASS for concurrent Hf + age technique to extract meaningful Hf isotope compositions in isotopically zoned zircon is demonstrated using zircons from two Proterozoic gneisses from northern Idaho, USA. These samples illustrate the potential problems associated with inadvertently sampling multiple age and Hf components in zircons, as well as the potential of LASS to recover meaningful Hf isotope compositions. We suggest that such inadvertent sampling of differing age and Hf components can be a significant cause of excess scatter in Hf isotope analyses and demonstrate that the LASS approach offers a robust solution to these issues. The veracity of the approach is demonstrated by accurate analyses of 10 reference zircons with well-characterized age and Hf isotopic composition, using laser spot diameters of 30 and 40 µm. In order to expand the database of high-precision Lu-Hf isotope analyses of reference zircons, we present 27 new isotope dilution-MC-ICPMS Lu-Hf isotope measurements of five U-Pb zircon standards: FC1, Temora, R33, QGNG, and 91500.

  16. Self-Rectifying Resistive Switching Memory with Ultralow Switching Current in Pt/Ta2O5/HfO2- x /Hf Stack

    NASA Astrophysics Data System (ADS)

    Ma, Haili; Feng, Jie; Lv, Hangbing; Gao, Tian; Xu, Xiaoxin; Luo, Qing; Gong, Tiancheng; Yuan, Peng

    2017-02-01

    In this study, we present a bilayer resistive switching memory device with Pt/Ta2O5/HfO2- x /Hf structure, which shows sub-1 μA ultralow operating current, median switching voltage, adequate ON/OFF ratio, and simultaneously containing excellent self-rectifying characteristics. The control sample with single HfO2- x structure shows bidirectional memory switching properties with symmetrical I-V curve in low resistance state. After introducing a 28-nm-thick Ta2O5 layer on HfO2- x layer, self-rectifying phenomena appeared, with a maximum self-rectifying ratio (RR) of 4 × 103 observed at ±0.5 V. Apart from being a series resistance for the cell, the Ta2O5 rectifying layer also served as an oxygen reservoir which remains intact during the whole switching cycle.

  17. Cross-correlation trajectory study of vibrational relaxation of DF(v = 1 to 7) by DF(v = 0) and of HF by HF

    SciTech Connect

    Coltrin, M.E.; Marcus, R.A.

    1982-03-01

    Three-dimensional quasiclassical trajectories and a cross-correlation method of analysis are used to study the vibrational relaxation of DF(v/sub 1/ = 1 to 7) by DF(v/sub 2/ = 0). Rate constants are calculated for V--V and V--R, T energy transfer. As was seen in earlier studies on HF--HF, the V--R, T mechanism becomes increasingly important at higher initial v/sub 1/, as the V--V transfer moves further off resonance and also becomes increasingly endothermic. Both factors contribute to the decrease of V--V transfer rates with increasing v/sub 1/ for the higher values of v/sub 1/. Comparisons are made with results of a classical path study of vibrational relaxation in DF--DF and with experiment where possible. New results on the HF--HF V--V transfer rates are presented.

  18. Air sensitivity of MoS2, MoSe2, MoTe2, HfS2, and HfSe2

    NASA Astrophysics Data System (ADS)

    Mirabelli, Gioele; McGeough, Conor; Schmidt, Michael; McCarthy, Eoin K.; Monaghan, Scott; Povey, Ian M.; McCarthy, Melissa; Gity, Farzan; Nagle, Roger; Hughes, Greg; Cafolla, Attilio; Hurley, Paul K.; Duffy, Ray

    2016-09-01

    A surface sensitivity study was performed on different transition-metal dichalcogenides (TMDs) under ambient conditions in order to understand which material is the most suitable for future device applications. Initially, Atomic Force Microscopy and Scanning Electron Microscopy studies were carried out over a period of 27 days on mechanically exfoliated flakes of 5 different TMDs, namely, MoS2, MoSe2, MoTe2, HfS2, and HfSe2. The most reactive were MoTe2 and HfSe2. HfSe2, in particular, showed surface protrusions after ambient exposure, reaching a height and width of approximately 60 nm after a single day. This study was later supplemented by Transmission Electron Microscopy (TEM) cross-sectional analysis, which showed hemispherical-shaped surface blisters that are amorphous in nature, approximately 180-240 nm tall and 420-540 nm wide, after 5 months of air exposure, as well as surface deformation in regions between these structures, related to surface oxidation. An X-ray photoelectron spectroscopy study of atmosphere exposed HfSe2 was conducted over various time scales, which indicated that the Hf undergoes a preferential reaction with oxygen as compared to the Se. Energy-Dispersive X-Ray Spectroscopy showed that the blisters are Se-rich; thus, it is theorised that HfO2 forms when the HfSe2 reacts in ambient, which in turn causes the Se atoms to be aggregated at the surface in the form of blisters. Overall, it is evident that air contact drastically affects the structural properties of TMD materials. This issue poses one of the biggest challenges for future TMD-based devices and technologies.

  19. Archean Lithosphere Beneath Arctic Canada: Lu-Hf Isotope Systematics for Kimberlite-Hosted Garnet-Peridotites From Somerset Island

    NASA Astrophysics Data System (ADS)

    Schmidberger, S. S.; Simonetti, A.; Francis, D.; Gariepy, C.

    2001-05-01

    Knowledge of the age of lithospheric mantle underlying the continents provides valuable constraints for the timing of formation and stabilization of Archean cratons. This study reports Lu-Hf isotopic data for garnet-peridotites, and their constituent garnets, from the Nikos kimberlite (100 Ma) on Somerset Island in the Canadian Arctic obtained using a Micromass IsoProbe multicollector inductively coupled plasma mass spectrometer (MC-ICP-MS) at GEOTOP-UQAM. The low temperature peridotites (<1100 C; 80-150 km) exhibit a significant range in 176Lu/177Hf ratios (0.03-0.05) and are characterized by radiogenic 176Hf/177Hf(0.1Ga) isotopic compositions (0.28294-0.28419) corresponding to \\epsilonHf(0.1Ga) values of +8 to +52. In contrast, 176Lu/177Hf ratios (0.004-0.04) are lower for the high temperature peridotites (>1100 C; 160-190 km) and their 176Hf/177Hf(0.1Ga) isotopic compositions (0.28265-0.28333; \\epsilonHf(0.1Ga)=-2 to +22) are less radiogenic than those of the shallow xenoliths. A Lu-Hf isochron for six peridotites yields a mid Archean age of 3.4\\pm0.3 Ga and an initial 176Hf/177Hf ratio of 0.28101\\pm24. The remaining peridotites (n=9), in contrast, are characterized by extremely high (+35) initial \\epsilonHf(3.4Ga) values, which correlate negatively with their 176Lu/177Hf ratios, suggesting addition of Hf as a result of metasomatic interaction with the host kimberlite. The garnets from the low temperature (3.4 Ga old) peridotites are characterized by high 176Lu/177Hf ratios and define an errorchron age of 1.4\\pm0.2 Ga, which may reflect re-equilibration of Hf during kimberlite magmatism.

  20. Lu-Hf and Sm-Nd evolution in lunar mare basalts

    NASA Technical Reports Server (NTRS)

    Unruh, D. M.; Tatsumoto, M.; Stille, P.; Patchett, P. J.

    1984-01-01

    Existing cumulate remelting models for mare basalt genesis are evaluated in light of Lu-Hf, Rb-Sr, Sm-Nd data and overall REE characteristics in order to determine the simplest model that can account for these data. A data base for comparing Lu-Hf evolution in the lunar mantle as inferred from Lu-Hf analyses of oceanic basalts is presented along with a preliminary comparison of Lu-Hf and Sm-Nd evolution betwee mare basalts and terrestrial oceanic basalts. It is found that Lu/Hf characteristics of mare basalts cannot be explained in terms of modal melting of cumulate sources formed from a magma ocean with chondritic Lu/Hf. The data are consistent with a model in which the cumulate sources formed from a light REE + HF-enriched magma ocean. Nonmodal melting of ilmenite in the sources is also required. The Lu-Hf data suggest that even the high-Ti basalt sources contained no more than about 3 percent ilmenite.

  1. Effects of sol aging on resistive switching behaviors of HfOx resistive memories

    NASA Astrophysics Data System (ADS)

    Hsu, Chih-Chieh; Sun, Jhen-Kai; Tsao, Che-Chang; Chen, Yu-Ting

    2017-03-01

    This work investigates effects of long-term sol-aging time on sol-gel HfOx resistive random access memories (RRAMs). A nontoxic solvent of ethanol is used to replace toxic 2-methoxyethanol, which is usually used in sol-gel processes. The top electrodes are fabricated by pressing indium balls onto the HfOx surface rather than by using conventional sputtering or evaporation processes. The maximum process temperature is limited to be 100 ℃. Therefore, influences of plasma and high temperature on HfOx film can be avoided. Under this circumstance, effects of sol aging time on the HfOx films can be more clearly studied. The current conduction mechanisms in low and high electric regions of the HfOx RRAM are found to be dominated by Ohmic conduction and trap-filled space charge limited conduction (TF-SCLC), respectively. When the sol aging time increases, the resistive switching characteristic of the HfOx layer becomes unstable and the transition voltage from Ohmic conduction to TF-SCLC is also increased. This suggests that an exceedingly long aging time will give a HfOx film with more defect states. The XPS results are consistent with FTIR analysis and they can further explain the unstable HfOx resistive switching characteristic induced by sol aging.

  2. Assessment and prevalence of pulmonary oedema in contemporary acute heart failure trials: a systematic review

    PubMed Central

    Platz, Elke; Jhund, Pardeep S.; Campbell, Ross T.; McMurray, John J.

    2015-01-01

    Aims Pulmonary oedema is a common and important finding in acute heart failure (AHF). We conducted a systematic review to describe the methods used to assess pulmonary oedema in recent randomized AHF trials and report its prevalence in these trials. Methods and results Of 23 AHF trials published between 2002 and 2013, six were excluded because they were very small or not randomized, or missing full-length publications. Of the remaining 17 (n = 200–7141) trials, six enrolled patients with HF and reduced ejection fraction (HF-REF) and 11, patients with both HF-REF and HF with preserved ejection fraction (HF-PEF). Pulmonary oedema was an essential inclusion criterion, in most trials, based upon findings on physical examination (‘rales’), radiographic criteria (‘signs of congestion’), or both. The prevalence of pulmonary oedema in HF-REF trials ranged from 75% to 83% and in combined HF-REF and HF-PEF trials from 51% to 100%. Five trials did not report the prevalence or extent of pulmonary oedema assessed by either clinical examination or chest x-ray. Improvement of pulmonary congestion with treatment was inconsistently reported and commonly grouped with other signs of congestion into a score. One trial suggested that patients with rales over >2/3 of the lung fields on admission were at higher risk of adverse outcomes than those without. Conclusion Although pulmonary oedema is a common finding in AHF, represents a therapeutic target, and may be of prognostic importance, recent trials used inconsistent criteria to define it, and did not consistently report its severity at baseline or its response to treatment. Consistent and ideally quantitative, methods for the assessment of pulmonary oedema in AHF trials are needed. PMID:26230356

  3. Ge interactions on HfO{sub 2} surfaces and kinetically driven patterning of Ge nanocrystals on HfO{sub 2}

    SciTech Connect

    Stanley, Scott K.; Joshi, Sachin V.; Banerjee, Sanjay K.; Ekerdt, John G.

    2006-01-15

    Germanium interactions are studied on HfO{sub 2} surfaces, which are prepared through physical vapor deposition (PVD) and by atomic layer deposition. X-ray photoelectron spectroscopy and temperature-programed desorption are used to follow the reactions of germanium on HfO{sub 2}. Germanium chemical vapor deposition at 870 K on HfO{sub 2} produces a GeO{sub x} adhesion layer, followed by growth of semiconducting Ge{sup 0}. PVD of 0.7 ML Ge (accomplished by thermally cracking GeH{sub 4} over a hot filament) also produces an initial GeO{sub x} layer, which is stable up to 800 K. PVD above 2.0 ML deposits semiconducting Ge{sup 0}. Temperature programed desorption experiments of {approx}1.0 ML Ge from HfO{sub 2} at 400-1100 K show GeH{sub 4} desorption below 600 K and GeO desorption above 850 K. These results are compared to Ge on SiO{sub 2} where GeO desorption is seen at 550 K. Exploiting the different reactivity of Ge on HfO{sub 2} and SiO{sub 2} allows a kinetically driven patterning scheme for high-density Ge nanoparticle growth on HfO{sub 2} surfaces that is demonstrated.

  4. Hf-Nd Isotopic and Trace-Element Geochemistry of Global Subducting Sediments

    NASA Astrophysics Data System (ADS)

    Vervoort, J. D.; Plank, T.; Patchett, P. J.

    2001-12-01

    Ferromanganese nodules, crusts, and associated metalliferous clays have long been known to have anomalously high Lu/Hf ratios and highly radiogenic Hf relative to Nd (Patchett et al., 1984; White et al., 1986). These oceanic sediments are some of the few terrestrial materials where Hf and Nd isotopes deviate from the crust-mantle array. This distinctive isotopic signature, therefore, has the potential to trace the fate of oceanic sediments through the subduction zone and into the mantle. It has recently been suggested, for example, that pelagic sediments can be detected in some Hawaiian basalts (Blichert-Toft et al., 1999) and in volcanic rocks from the Luzon arc (Marini et al., 2000) based on their Hf-Nd isotopic compositions. The weak link in this approach, however, is that we do not know, in any quantitative way, how widespread this anomalous signature is in oceanic sediments, what compositions are responsible for this signature, or how volumetrically important these compositions are in terms of the total sediment flux into subduction zones and the mantle. Most marine sediments analyzed thus far have been collected on or near the ocean floor and constitute an incomplete and unrepresentative inventory of the sediment column bound for the subduction zone. There is some reason to suspect that much of the sediment flux is not particularly anomalous, either in terms of Lu/Hf ratios or Hf and Nd isotopic compositions. The most dominant sediment types entering many subduction zones (terrigenous and other continentally derived sediments), have normal Lu/Hf ratios and Hf-Nd isotopic compositions that are indistinguishable from the crust-mantle array. An examination is needed of the Hf-Nd isotopic composition of oceanic sediments, the major and trace-element geochemistry of global sediment flux, how such compositions may relate to Hf-Nd isotopic behavior, and potential Lu/Hf and Nd/Hf fractionation in subduction zones. In addition, the origin of the high Lu/Hf and

  5. HF beam parameters in ELF/VLF wave generation via modulated heating of the ionosphere

    NASA Astrophysics Data System (ADS)

    Cohen, M. B.; Golkowski, M.; Lehtinen, N. G.; Inan, U. S.; McCarrick, M. J.

    2012-05-01

    ELF/VLF (0.3-30 kHz) wave generation is achievable via modulated HF (3-30 MHz) heating of the lower ionosphere in the presence of natural currents such as the auroral electrojet. Using the 3.6 MW High Frequency Active Auroral Research Program (HAARP) facility near Gakona, AK, we investigate the effect of HF frequency and beam size on the generated ELF/VLF amplitudes, as a function of modulation frequency, and find that generation in the Earth-ionosphere waveguide generally decreases with increasing HF frequency between 2.75-9.50 MHz. HAARP is also capable of spreading the HF power over a wider area, and we find that a larger beam area yields larger generated amplitudes on the ground. Measurements are shown to generally agree with a theoretical model, which is then applied to also predict the effect of HF beam parameters on magnetospheric injection with HAARP.

  6. Surface treatment for the atomic layer deposition of HfO2 on silicon

    NASA Astrophysics Data System (ADS)

    Damlencourt, J.-F.; Renault, O.; Martin, F.; Séméria, M.-N.; Billon, T.; Bedu, F.

    2005-04-01

    The atomic layer deposition (ALD) of HfO2 on silicon with a Cl2 surface treatment is investigated by physicochemical and electrical techniques. The specificity of this treatment is to create, on a HF-dipped silicon surface, the nucleation sites necessary for the ALD growth. The growth rates obtained by spectroscopic ellipsometry and total x-ray fluorescence spectroscopy indicate that the nucleation sites (i.e., the -OH groups), which are necessary to perform some bidimensional ALD growth, are generated during this surface treatment. After deposition of thin HfO2 layers (from a few monolayers up to 8.7nm), a very thin parasitic SiOx layer, underneath 1 monolayer of Hf silicate, is observed by x-ray photoelectron spectroscopy. Nevertheless, an equivalent oxide thickness of 1.1nm is obtained with an as-deposited 3.7nm thick HfO2 layer.

  7. Thermal decomposition of HfCl{sub 4} as a function of its hydration state

    SciTech Connect

    Barraud, E.; Begin-Colin, S. . E-mail: begin@ipcms.u-strasbg.fr; Le Caer, G.; Villieras, F.; Barres, O.

    2006-06-15

    The thermogravimetric behavior of HfCl{sub 4} powders with different hydration states has been compared. Strongly hydrated powders consist of HfOCl{sub 2}.nH{sub 2}O with n>4. Partially hydrated powders consist of particles with a HfCl{sub 4} core and a hydrated outerlayer of HfOCl{sub 2}.nH{sub 2}O with n in the range of 0-8. Hydrated powders decomposed at temperature lower than 200 deg. C whereas the decomposition of partially hydrated powders was completed at a temperature of around 450 deg. C. The observed differences in decomposition temperature is related to the structure of HfOCl{sub 2}.nH{sub 2}O, which is different if n is higher or smaller than 4 and leads to intermediate compounds, which decompose at different temperatures.

  8. Theory of large-scale HF heating processes in the unstructured and structured ionosphere

    SciTech Connect

    Keskinen, M.J.; Chaturvedi, P.K.; Ossakow, S.L.

    1990-10-01

    Theoretical aspects of large-scale HF heating processes in the unstructured and structured ionosphere have been studied. For the unstructured case, we present an analytical model for the generation, convection, and steepening of HF-induced density cavities. We discuss the nonlinear propagation of high power HF in steepened cavities. Properties of thermal self-focusing instabilities in the presence of a convecting and steepened cavity is studied. For the structured ionosphere, we discuss parametric coupling processes of a large amplitude HF pump wave with both F-region, i.e., interchange, current-convective, and ion cyclotron and E-region, i.e., two-stream and gradient-drift ionospheric instabilities which instabilities have been proposed to account, in part, for naturally occurring ionospheric irregularities. We show that these instabilities may be stabilized or destabilized using high power HF heaters.

  9. Simultaneous HF-radar and DMSP observations of the cusp

    SciTech Connect

    Baker, K.B.; Greenwald, R.A.; Ruohoniemi, J.M.; Dudeney, J.R.; Pinnock, M.; Newell, P.T.; Greenspan, M.E.; Meng, C.I.

    1990-10-01

    The Geospace Environment Modeling (GEM) Program is directed toward modeling the coupled solar wind/magnetosphere/ionosphere system. The inter-calibration of ground-based observations of the ionosphere and satellite observations has been identified as an essential step in tying together the data to produce a global picture of geospace. On October 10, 1988 the DMSP-F9 satellite passed through the southern hemisphere cusp while a coherent scatter HF-radar was observing 10-m scale irregularities present in the ionosphere. The combined data indicate that these irregularities were being generated in the cusp, and that the cusp was a region of greater than normal electric field turbulence. The radar data indicate that the cusp was co-located with the region where the ionospheric convection rotated from sunward to anti-sunward with increasing latitude. These observations provide an unambiguous case where simultaneous satellite and ground-based observations of the cusp can be compared.

  10. Temporal and spatial resolution of HF ocean radars

    NASA Astrophysics Data System (ADS)

    Heron, Malcom L.; Atwater, Daniel P.

    2013-03-01

    The spatial and temporal resolutions of the two main types of HF radar are compared, with reference to the phasedarray and the crossed-loop direction-finding systems which make up the Australian Coastal Ocean radar Network. Both genres use a swept frequency "chirp" modulation to define the range of a pixel being observed but the method for determining the azimuth direction of the pixel is a strong point of differentiation. The phased-array systems produce independent maps of surface currents in about 1/7 of the time for the crossed-loop systems because of contrasting noise performance of the antennas. The use of beam-forming analysis in the phased-arrays is shown to give spatial resolutions, for vector currents, of about 10 km close to the shore, and 25 km at ranges of 150 km. The corresponding vector current spatial resolutions for the crossed-loop systems are 40 km and 60 km respectively.

  11. Digital hf radar observations of equatorial spread-F

    SciTech Connect

    Argo, P.E.

    1984-01-01

    Modern digital ionosondes, with both direction finding and doppler capabilities can provide large scale pictures of the Spread-F irregularity regions. A morphological framework has been developed that allows interpretation of the hf radar data. A large scale irregularity structure is found to be nightward of the dusk terminator, stationary in the solar reference frame. As the plasma moves through this foehn-wall-like structure it descends, and irregularities may be generated. Localized upwellings, or bubbles, may be produced, and they drift with the background plasma. The spread-F irregularity region is found to be best characterized as a partly cloudy sky, due to the patchiness of the substructures. 13 references, 16 figures.

  12. Plasma perturbations HF-induced in the topside ionosphere

    NASA Astrophysics Data System (ADS)

    Zhang, Xuemin; Frolov, Vladimir; Zhou, Chen; Zhao, Shufan; Ruzhin, Yury; Shen, Xuhui; Zhima, Zeren; Liu, Jing

    2016-10-01

    Three plasma perturbations induced by SURA HF (high-frequency) heating have been selected and analyzed in detail with the DEMETER satellite observing data by instruments of Langmuir probe and ion analyzer. Some common features are revealed, such as (1) electron density and electron temperature both increased during the heating period; (2) both O+ density and ion temperature also increased generally, while H+ varied negatively with O+ density; (3) the ions were accelerated in upward and northward directions, resulting from the thermal pressure gradient, which also caused the variations in ULF (ultralow-frequency) electric field due to V>⇀×B>⇀ effects; and (4) the simulation results verify the electron density and temperature enhancement at the topside ionosphere due to the ohmic heating process and thermal self-focusing instability over the heating region, which is consistent with the observing phenomena by the DEMETER satellite.

  13. Observation of weak HF electrostatic turbulence in the auroral ionosphere

    NASA Astrophysics Data System (ADS)

    Pottelette, R.; Illiano, J. M.

    1982-07-01

    A numerical calculation of the cross spectrum of random signals received by two small antennas that were immersed in a two-component magnetoplasma has been conducted, for the case of a plasma model consisting of a cool and a warm component. The data were compiled by the HF electrostatic wave detection experiment of the Porcupine F3 rocket. A linear calculation of the natural electrostatic emissions detected around the electron gyrofrequency three-halves harmonic and around the upper hybrid frequency shows that their amplitudes are above the plasma thermal noise level. It is noted that the low energy precipitating suprathermal electrons present are highly anisotropic and enhance the three-halves electron gyrofrequency noise, although the electron distribution function remains stable and the most intense emissions are observed around the upper hybrid frequency.

  14. Automatic scaling of HF swept-frequency backscatter ionograms

    NASA Astrophysics Data System (ADS)

    Song, Huan; Hu, Yaogai; Jiang, Chunhua; Zhou, Chen; Zhao, Zhengyu

    2015-05-01

    This paper describes a method for automatically scaling HF swept-frequency backscatter ionograms, which can be applied to a low-power oblique backscatter sounding system. Based on the information of vertical echo in the ionogram, propagation mode is recognized from the amplitude differences between E layer and F layer echoes. Points on the leading edge are extracted by using minimum group path delay theory. The spurious points are removed by using residual analysis. A multiple linear polynomial was adopted to fit the extracted leading edge points. Smooth fitting curves can then be obtained. Automatic scaling results from 362 ionograms show that the proposed method can efficiently recognize propagation modes and extract leading edge curves by taking full advantages of echo characteristics and echo amplitudes in the ionograms. This novel method can be applied into real-time backscatter ionogram scaling, which facilitates the extensive usage of oblique backscatter soundings.

  15. Ternary ceramic alloys of Zr-Ce-Hf oxides

    DOEpatents

    Becher, P.F.; Funkenbusch, E.F.

    1990-11-20

    A ternary ceramic alloy is described which produces toughening of zirconia and zirconia composites through the stress transformation from tetragonal phase to monoclinic phase. This alloy, having the general formula Ce[sub x]Hf[sub y]Zr[sub 1[minus]x[minus]y]O[sub 2], is produced through the addition of appropriate amounts of ceria and hafnia to the zirconia. Typically, improved toughness is achieved with about 5 to about 15 mol % ceria and up to about 40 mol % hafnia. The preparation of alloys of these compositions are given together with data as to the densities, tetragonal phase content, hardness and fracture toughness. The alloys are useful in preparing zirconia bodies as well as reinforcing ceramic composites. 1 fig.

  16. Ternary ceramic alloys of ZR-CE-HF oxides

    DOEpatents

    Becher, Paul F.; Funkenbusch, Eric F.

    1990-01-01

    A ternary ceramic alloy which produces toughening of zirconia and zirconia composites through the stress transformation from tetragonal phase to monoclinic phase. This alloy, having the general formula Ce.sub.x Hf.sub.y Zn.sub.1-x-y O.sub.2, is produced through the addition of appropriate amounts of ceria and hafnia to the zirconia. Typically, improved toughness is achieved with about 5 to about 15 mol % ceria and up to about 40 mol % hafnia. The preparation of alloys of these compositions are given together with data as to the densities, tetragonal phase content, hardness and fracture toughness. The alloys are useful in preparing zirconia bodies as well as reinforcing ceramic composites.

  17. Polymorphisms in the IL-1 gene cluster influence systemic inflammation in patients at risk for acute-on-chronic liver failure.

    PubMed

    Alcaraz-Quiles, José; Titos, Esther; Casulleras, Mireia; Pavesi, Marco; López-Vicario, Cristina; Rius, Bibiana; Lopategi, Aritz; de Gottardi, Andrea; Graziadei, Ivo; Gronbaek, Henning; Ginès, Pere; Bernardi, Mauro; Arroyo, Vicente; Clària, Joan

    2017-01-01

    Acute-on-chronic liver failure (ACLF) in cirrhosis is an increasingly recognized syndrome characterized by acute decompensation, organ failure(s) and high short-term mortality. Recent findings suggest that an overexuberant systemic inflammation plays a primary role in ACLF progression. In this study, we examined whether genetic factors shape systemic immune responses in patients with decompensated cirrhosis. Six single-nucleotide polymorphisms (SNPs) in inflammation-related genes (interleukin [IL]-1 beta [IL-1β], rs1143623; IL-1 receptor antagonist [IL-1ra], rs4251961; IL-10, rs1800871; suppressor of cytokine signaling-3, rs4969170; nucleotide-binding oligomerization domain-containing protein 2, rs3135500; and chemerin chemokine-like receptor 1, rs1878022) were genotyped in 279 patients with cirrhosis with (n = 178) and without (n = 101) ACLF from the CANONIC study of the CLIF consortium. Among these SNPs, we identified two polymorphisms belonging to the IL-1 gene cluster (IL-1β and IL-1ra) in strong association with ACLF. Both SNPs were protective against ACLF; IL-1β (odds ratio [OR], 0.34, 95% confidence interval [CI], 0.13-0.89; P < 0.05) and IL-1ra (OR, 0.58; 95% CI, 0.35-0.95; P < 0.05) under the recessive and overdominant inheritance models, respectively. These protective SNPs translated into reduced circulating levels of IL-1β, IL-1α, IL-6, granulocyte-colony stimulating factor, granulocyte-macrophage colony-stimulating factor, and C-reactive protein at enrollment as well as after 7-14 days of admission. These findings were confirmed in vitro in leukocytes incubated with plasma from patients with decompensated cirrhosis carrying the protective SNP genotypes. Notably, a higher frequency of the protective genotypes was observed in patients without (80%) than in those with (20%) ACLF. Consistently, patients carrying the combined protective genotypes showed a lower 28-day mortality rate.

  18. Single layer of Ge quantum dots in HfO2 for floating gate memory capacitors.

    PubMed

    Lepadatu, A M; Palade, C; Slav, A; Maraloiu, A V; Lazanu, S; Stoica, T; Logofatu, C; Teodorescu, V S; Ciurea, M L

    2017-04-28

    High performance trilayer memory capacitors with a floating gate of a single layer of Ge quantum dots (QDs) in HfO2 were fabricated using magnetron sputtering followed by rapid thermal annealing (RTA). The layer sequence of the capacitors is gate HfO 2/floating gate of single layer of Ge QDs in HfO 2/tunnel HfO 2/p-Si wafers. Both Ge and HfO2 are nanostructured by RTA at moderate temperatures of 600-700 °C. By nanostructuring at 600 °C, the formation of a single layer of well separated Ge QDs with diameters of 2-3 nm at a density of 4-5 × 10(15) m(-2) is achieved in the floating gate (intermediate layer). The Ge QDs inside the intermediate layer are arranged in a single layer and are separated from each other by HfO2 nanocrystals (NCs) about 8 nm in diameter with a tetragonal/orthorhombic structure. The Ge QDs in the single layer are located at the crossing of the HfO2 NCs boundaries. In the intermediate layer, besides Ge QDs, a part of the Ge atoms is segregated by RTA at the HfO2 NCs boundaries, while another part of the Ge atoms is present inside the HfO2 lattice stabilizing the tetragonal/orthorhombic structure. The fabricated capacitors show a memory window of 3.8 ± 0.5 V and a capacitance-time characteristic with 14% capacitance decay in the first 3000-4000 s followed by a very slow capacitance decrease extrapolated to 50% after 10 years. This high performance is mainly due to the floating gate of a single layer of well separated Ge QDs in HfO2, distanced from the Si substrate by the tunnel oxide layer with a precise thickness.

  19. Analysis of D-Region Absorption via HF Cross-Modulation Experiments at HAARP

    NASA Astrophysics Data System (ADS)

    Braun, E. M.; Moore, R. C.

    2010-12-01

    Experimental observations performed near the High-frequency Active Auroral Research Program (HAARP) HF transmitter in Gakona, Alaska are used to implement a new method quantifying the rate of absorption of HF radio waves in the D-region ionosphere. Quantifying the ambient and HF-modified characteristics of the D-region ionosphere in the vicinity of ionospheric HF heaters has historically proven to be a difficult task. For example, the electron density in the 60-90 km altitude range is typically too low to employ radio-sounding techniques; LIDAR observations typically require significant temporal averaging, precluding the investigation of physical processes that occur on sub-millisecond time scales; ELF/VLF wave generation experiments typically have difficulty providing reliable spatial resolution and also cannot experimentally distinguish between the spatial distribution of the ionospheric conductivity modulation produced by modulated HF heating and that of the current-driving electric fields associated with the auroral electrojet. Yet, the majority of HF signal absorption occurs in this region of the ionosphere, and the ability to characterize HF absorption in this region benefits a wide range of ionospheric HF heating experiments. The technique described and demonstrated in this paper combines ionosonde-style radio sounding with ELF/VLF cross-modulation experiments to identify the altitude of maximum D-region absorption as a function of HF frequency. Observations are presented and compared with the predictions of a theoretical model, demonstrating excellent agreement between experiment and theory and indicating that the technique may be used successfully in practice. Based on the success of this first experiment, another HF cross-modulation experiment has been performed at HAARP and analyzed theoretically. Pulsed-modulation experiments are used to assess the relative absorption as a function of altitude within the D-region ionosphere, and a method to chart the

  20. Garnet effect on Nd-Hf isotope decoupling: Evidence from the Jinfosi batholith, Northern Tibetan Plateau

    NASA Astrophysics Data System (ADS)

    Huang, Hui; Niu, Yaoling; Mo, Xuanxue

    2017-03-01

    The initial Nd and Hf isotope ratios of a 420 Ma post-collisional dioritic-granitic batholith from the Northern Tibetan plateau define a negative trend above and orthogonal to the ԐHf(t)-ԐNd(t) terrestrial array. This uncommon trend offers an insight into the origin of the puzzling Nd-Hf isotope decoupling in the crustal rocks. On this trend, samples depleted in heavy rare earth elements (HREEs, i.e., [Dy/Yb]N ≫ 1) deviate most from the terrestrial array whereas samples with flat HREEs (i.e., [Dy/Yb]N ≥ 1) deviate less or plot within the terrestrial array, pointing to the controlling effect of garnet in the magma source. Ancient garnet-bearing residues after melt extraction will have elevated Lu/Hf ratios and can evolve with time to produce high ԐHf(t) at a low ԐNd(t) value. Mixing of melts derived from such source lithologies (high Lu/Hf) with melts possessing a within-terrestrial array Nd-Hf isotopic composition (low Lu/Hf) best explains the observed trend orthogonal to the terrestrial array. The samples from the Jinfosi batholith with the most decoupled Nd-Hf isotope compositions require a larger degree (> 40%) and ancient (i.e., ≥ 1.8 Gyr) previous melt extraction from their source. It follows that the ancient melts with depleted HREEs complementary to those garnet-bearing residues should have low ԐHf values and plot below the terrestrial array, which is indeed shown by some Archean/Paleoproterozic TTGs.

  1. Electronic Structure Differences in ZrO2 vs. HfO2

    SciTech Connect

    Zheng, Weijun; Bowen Jr., K.H.; Li, Jun; Dabkowska, Iwona; Gutowski, Maciej S.

    2005-12-22

    While ZrO2 and HfO2 are, for the most part, quite similar chemically, subtle differences in their electronic structures appear to be responsible for differing MO2/Si (M = Zr, Hf) interface stabilities. In order to shed light on the electronic structure differences between ZrO2 and HfO2, we have conducted joint experimental/theoretical studies. Since electron affinities are a sensitive probe of electronic structure, we have measured them by conducting photoelectron spectroscopic experiments on ZrO2- and HfO2-. The electron affinity of HfO2 was determined to be 2.14? 0.03 eV, while that of ZrO2 was determined to be 1.64 ? 0.03 eV. Concurrently, electronic structure calculations were conducted to determine electron affinities, vibrational frequencies, and geometries of these systems. The calculated electron affinities of HfO2 and ZrO2 were found to be 2.05 and 1.62 eV, respectively. The molecular results confirm earlier predictions from solid phases that HfO2 is more ionic than ZrO2. The excess electron in MO2- occupies an sd-type hybrid orbital localized on the M atom (M=Zr, Hf). The structural parameters of ZrO2 and HfO2 were found to be very similar. The difference in geometries between the neutral and the anion is along the symmetrical stretching and bending modes. Together, these studies unveil significant differences in the electronic structures of ZrO2 and HfO2.

  2. Hardness and Second Phase Percentage of Ni-Ti-Hf Compounds After Heat Treatment at 700C

    NASA Technical Reports Server (NTRS)

    Stanford, Malcolm K.

    2017-01-01

    The Vickers hardness and second phase precipitation of three ternary intermetallic Ni-Ti-Hf compounds containing either 1, 3 or 5 at.% Hf were compared to 60-Nitinol (55 at.% Ni - 45 at.% Ti). Heat treatment either at 700 C or with a subsequent aging step, hardened the 3 and 5 at.% Hf-containing ternaries to approximately 620 HV (56 HRC). Heat treatment increased the hardness of the 1 at.% Hf compound by more than 25 percent. Average hardness of the 3 and 5 at.% Hf ternaries, though higher than that of the binary Ni-Ti or the Ni-Ti-Hf compound containing 1 at.% Hf, appeared to be fairly insensitive to the different heat treatments. There was a drastic reduction of fatigue-enhancing second phase precipitates for the 5 at.% Hf ternaries compared to the other compounds. These results should guide materials selection for development of aerospace componentry.

  3. Effect of Li/Nb Ratio on Growth and Spectrometric Characterization of Hf:Fe:LiNbO3 Crystals

    NASA Astrophysics Data System (ADS)

    Dai, Li; Wu, Shi-Ping; Guo, Jing-Jie; Xu, Chao; Su, Yan-Qing; Xu, Yu-Heng

    Hf:Fe:LiNbO3 crystals were grown by the Czochralski technique with various ratios of Li/Nb = 0.946, 1.05, 1.20 and 1.38 in the melt. The crystal composition and defect structure were analyzed by XRD, UV-Vis and IR spectroscopy. The results show that the threshold concentration of Hf in LiNbO3 crystals decrease with the increasing of the Li/Nb ratio; when the Li/Nb ratio is 1.05, the threshold concentration of Hf is less than 2 mol%, largely under the threshold concentration of Hf ions in congruent Hf:Fe:LiNbO3 crystal (4 mol).1-3 With the increase of Li/Nb, Hf ions first replace the Nb4+ Li; when the concentration of Hf ions is higher than the threshold value, Hf ions occurs on normal Nb and Li sites.

  4. Mixing and melt sources in the Miocene Aztec Wash pluton (Nevada, USA) as revealed by zircon Hf and O and whole rock Sr, Nd, and Hf isotopes

    NASA Astrophysics Data System (ADS)

    Ryan, M.; Miller, J. S.; Miller, C. F.; Bromley, S.; Davies, G. R.; Schmitt, A. K.

    2011-12-01

    The 15.6 Ma Aztec Wash Pluton (AWP) is one of several Miocene intrusions located within the northern Colorado River extensional corridor. Extensive E-W tilting of fault blocks has exposed the pluton from the roof to 5 km structural depth. Earlier field and petrologic studies subdivided the AWP into two distinct zones: (1) a Granite Zone (GZ) comprised of relatively homogeneous granite with subtle differences in textures and mineralogy; (2) a Heterogeneous Zone (HZ), which interfingers the GZ, contains evidence for mafic and felsic magma input with a wide compositional range (42-78 wt% SiO2), and abundant field evidence for hybridization. Previous whole rock geochemistry and zircon trace element analyses indicated that compositional variation was produced by multi-component mixing between mafic and felsic melts within the HZ. New whole rock Sr, Nd, and Hf isotope data from the HZ show that all rocks (including high-silica granites) formed by mixing Precambrian crust and enriched mantle, with mixtures having a large mantle fraction (≥50%). New Hf (n=189) and O (n=241) isotope analyses of zircon from samples in the HZ confirm these melt sources and provide a broader perspective on hybridization processes within the AWP. Zircon grains from all samples show heterogeneous Hf and O isotopic compositions (-5 to -18 ɛHf; 4.5-7.5% δ18O), but despite the clear signature of Precambrian crust in the whole rock data, obvious Precambrian zircons (or cores) were mostly absent; only one zircon was clearly Precambrian (ɛHf = -25). Resolvable intragrain variability is relatively limited (including the Precambrian grain, which is unzoned). Zircons from hand samples and from compositional groups also show heterogeneous ɛHf and δ18O values, although the spreads are more restricted than in the whole data set (6-10 ɛHf in granites, 5-7 ɛHf in intermediate "hybrids", 5-6 ɛHf in gabbro/diorite sheets). Oxygen isotope values for the zircons also show intra-handsample heterogeneity

  5. Synthesis of amorphous alloys and amorphous-crystalline composites in the Cu-Nb-Hf system by ion beam mixing

    SciTech Connect

    Luo, S. Y.; Cui, Y. Y.; Wang, T. L.; Ding, N.; Li, J. H.; Liu, B. X.

    2011-06-15

    Seven sets of Cu-Nb-Hf multilayered films were designed and prepared with the overall compositions of Cu{sub 21}Nb{sub 65}Hf{sub 14}, Cu{sub 33}Nb{sub 49}Hf{sub 18}, Cu{sub 34}Nb{sub 34}Hf{sub 32}, Cu{sub 34}Nb{sub 10}Hf{sub 56}, Cu{sub 50}Nb{sub 23}Hf{sub 27}, Cu{sub 58}Nb{sub 10}Hf{sub 32}, and Cu{sub 70}Nb{sub 8}Hf{sub 22}, and an ion beam mixing experiment was then conducted using 200 keV xenon ions. It is found that the Cu-Nb-Hf system is a metallic glass forming one, and the single amorphous alloys could be synthesized in the Cu-Nb-based alloys with less than 18 at.% of Hf as a third addition. Also, when the Hf concentration is greater than 18 at.%, i.e., at the compositions of Cu{sub 34}Nb{sub 34}Hf{sub 32}, Cu{sub 34}Nb{sub 10}Hf{sub 56}, Cu{sub 50}Nb{sub 23}Hf{sub 27}, Cu{sub 58}Nb{sub 10}Hf{sub 32}, and Cu{sub 70}Nb{sub 8}Hf{sub 22}, ion beam mixing resulted in the formation of amorphous-crystalline composites, which might have better mechanical properties than single-phase glassy alloys. In addition, a detailed discussion was presented for the formation mechanism of the amorphous alloys and amorphous-crystalline composites.

  6. Cardiorenal Syndrome in Acute Heart Failure: Revisiting Paradigms.

    PubMed

    Núñez, Julio; Miñana, Gema; Santas, Enrique; Bertomeu-González, Vicente

    2015-05-01

    Cardiorenal syndrome has been defined as the simultaneous dysfunction of both the heart and the kidney. Worsening renal function that occurs in patients with acute heart failure has been classified as cardiorenal syndrome type 1. In this setting, worsening renal function is a common finding and is due to complex, multifactorial, and not fully understood processes involving hemodynamic (renal arterial hypoperfusion and renal venous congestion) and nonhemodynamic factors. Traditionally, worsening renal function has been associated with worse outcomes, but recent findings have revealed mixed and heterogeneous results, perhaps suggesting that the same phenotype represents a diversity of pathophysiological and clinical situations. Interpreting the magnitude and chronology of renal changes together with baseline renal function, fluid overload status, and clinical response to therapy might help clinicians to unravel the clinical meaning of renal function changes that occur during an episode of heart failure decompensation. In this article, we critically review the contemporary evidence on the pathophysiology and clinical aspects of worsening renal function in acute heart failure.

  7. Design for human factors (DfHF): a grounded theory for integrating human factors into production design processes.

    PubMed

    Village, Judy; Searcy, Cory; Salustri, Filipo; Patrick Neumann, W

    2015-01-01

    The 'design for human factors' grounded theory explains 'how' human factors (HF) went from a reactive, after-injury programme in safety, to being proactively integrated into each step of the production design process. In this longitudinal case study collaboration with engineers and HF Specialists in a large electronics manufacturer, qualitative data (e.g. meetings, interviews, observations and reflections) were analysed using a grounded theory methodology. The central tenet in the theory is that when HF Specialists acclimated to the engineering process, language and tools, and strategically aligned HF to the design and business goals of the organisation, HF became a means to improve business performance. This led to engineers 'pulling' HF Specialists onto their team. HF targets were adopted into engineering tools to communicate HF concerns quantitatively, drive continuous improvement, visibly demonstrate change and lead to benchmarking. Senior management held engineers accountable for HF as a key performance indicator, thus integrating HF into the production design process. Practitioner Summary: Research and practice lack explanations about how HF can be integrated early in design of production systems. This three-year case study and the theory derived demonstrate how ergonomists changed their focus to align with design and business goals to integrate HF into the design process.

  8. First experimental evidence of HF produced electron density irregularities in the polar ionosphere; diagnosed by UHF radio star scintillations

    SciTech Connect

    Frey, A.; Stubbe, P.; Kopka, H.

    1984-05-01

    HF-produced electron density irregularities with scale sizes of several hundred meters were observed in the polar ionosphere by means of UHF-scintillations using the new facilities at Tromso. HF-power densities as low as 20 ..mu..W/m/sup 2/ excited irregularities during over-dense (HF

  9. Acute Pancreatitis

    PubMed Central

    Geokas, Michael C.

    1972-01-01

    For many decades two types of acute pancreatitis have been recognized: the edematous or interstitial and the hemorrhagic or necrotic. In most cases acute pancreatitis is associated with alcoholism or biliary tract disease. Elevated serum or urinary α-amylase is the most important finding in diagnosis. The presence of methemalbumin in serum and in peritoneal or pleural fluid supports the diagnosis of the hemorrhagic form of the disease in patients with a history and enzyme studies suggestive of pancreatitis. There is no characteristic clinical picture in acute pancreatitis, and its complications are legion. Pancreatic pseudocyst is probably the most common and pancreatic abscess is the most serious complication. The pathogenetic principle is autodigestion, but the precise sequence of biochemical events is unclear, especially the mode of trypsinogen activation and the role of lysosomal hydrolases. A host of metabolic derangements have been identified in acute pancreatitis, involving lipid, glucose, calcium and magnesium metabolism and changes of the blood clotting mechanism, to name but a few. Medical treatment includes intestinal decompression, analgesics, correction of hypovolemia and other supportive and protective measures. Surgical exploration is advisable in selected cases, when the diagnosis is in doubt, and is considered imperative in the presence of certain complications, especially pancreatic abscess. PMID:4559467

  10. Photocurrent generation in carbon nanotube/cubic-phase HfO2 nanoparticle hybrid nanocomposites

    PubMed Central

    Galeckas, Augustinas; Salumaa, Martin; Ducroquet, Frédérique; Rauwel, Erwan

    2016-01-01

    Summary A hybrid material consisting of nonfunctionalized multiwall carbon nanotubes (MWCNTs) and cubic-phase HfO2 nanoparticles (NPs) with an average diameter of 2.6 nm has been synthesized. Free standing HfO2 NPs present unusual optical properties and a strong photoluminescence emission in the visible region, originating from surface defects. Transmission electron microscopy studies show that these NPs decorate the MWCNTs on topological defect sites. The electronic structure of the C K-edge in the nanocomposites was probed by electron energy loss spectroscopy, highlighting the key role of the MWCNT growth defects in anchoring HfO2 NPs. A combined optical emission and absorption spectroscopy approach illustrated that, in contrast to HfO2 NPs, the metallic MWCNTs do not emit light but instead expose their discrete electronic structure in the absorption spectra. The hybrid material manifests characteristic absorption features with a gradual merger of the MWCNT π-plasmon resonance band with the intrinsic defect band and fundamental edge of HfO2. The photoluminescence of the nanocomposites indicates features attributed to combined effects of charge desaturation of HfO2 surface states and charge transfer to the MWCNTs with an overall reduction of radiative recombination. Finally, photocurrent generation under UV–vis illumination suggests that a HfO2 NP/MWCNT hybrid system can be used as a flexible nanodevice for light harvesting applications. PMID:27547626

  11. Removal of B from Si by Hf addition during Al–Si solvent refining process

    PubMed Central

    Lei, Yun; Ma, Wenhui; Sun, Luen; Wu, Jijun; Dai, Yongnian; Morita, Kazuki

    2016-01-01

    Abstract A small amount of Hf was employed as a new additive to improve B removal in the electromagnetic solidification refinement of Si with an Al–Si melt, because Hf has a very strong affinity for B. The segregation ratio of Hf between the solid Si and Al–Si melt was estimated to range from 4.9 × 10−6 to 8.8 × 10−7 for Al concentrations of 0 to 64 at.%, respectively. The activity coefficient of Hf in solid Si at its infinite dilution was also estimated. A small addition of Hf (<1025 parts per million atoms, ppma) significantly improved the B removal. It was confirmed that the use of an increased Hf addition, slower cooling rate, and Al-rich Al–Si melt as the refining solvent removed B more efficiently. B in Si could be removed as much as 98.2% with 410 ppma Hf addition when the liquidus temperature of the Al–Si melt was 1173 K and the cooling rate was 4.5–7.6 K min–1. The B content in Si could be controlled from 153 ppma to 2.7 ppma, which meets the acceptable level for solar-grade Si. PMID:27877853

  12. Microstructural Investigation and Phase Relationships of Fe-Al-Hf Alloys

    NASA Astrophysics Data System (ADS)

    Yildirim, Mehmet; Akdeniz, M. Vedat; Mekhrabov, Amdulla O.

    2014-07-01

    The effect of Hf addition on microstructures, phase relationships, microhardness, and magnetic properties of Fe50Al50- n Hf n alloys for n = 1, 3, 5, 7, and 9 at. pct has been investigated. At all investigated compositions, the ternary intermetallic HfFe6Al6 τ 1 phase forms due to the limited solid solubility of Hf in FeAl phase and tends to develop a eutectic phase mixture with the Fe-Al-based phase. The Hf concentration of the eutectic composition is found to be 7 at. pct from the microstructural examinations and the eutectic phase transition temperature is determined as 1521 K (1248 °C) independent of Hf amount by differential scanning calorimetry measurements. Furthermore, the enthalpies and activation energies (based on Kissinger and Ozawa methods) of eutectic phase transitions are reported. The minimum activation energy is calculated for the fully eutectic composition. Moreover, variation of the microhardness of Fe-Al-based alloys as a function of the Hf content is investigated, and its dependence on the thermal history of the alloys is explained.

  13. Determination of Energy Band Alignment in Ultrathin Hf-based Oxide/Pt System

    NASA Astrophysics Data System (ADS)

    Ohta, A.; Murakami, H.; Higashi, S.; Miyazaki, S.

    2013-03-01

    Effect of incorporating a third element into HfO2 on the electronic structures has been studied by high resolution x-ray photoelectron spectroscopy (XPS). Hf-IIIa (La, Y, Gd, and Dy) oxide and Hf-Ti oxide films were deposited on a Pt layer by metal organic chemical vapor deposition (MOCVD) and co-sputtering and followed by post-deposition annealing in O2 ambience at 500°C. The energy bandgap (Eg) of these Hf-based oxide films was determined by analyzing the energy loss spectra of O 1s photoelectrons in consideration of the overlap with Hf 4s core-line signals. From analyses of the valence band signals and the cut-off energy for photoelectrons, the valence band offset between the Hf based-oxide, and the Pt electrode and the work function value of the Pt layer were evaluated. By combining the oxide bandgap values, the valence band line-ups, and the Pt work function value, the energy band profile of the Hf-based oxide/Pt has been determined.

  14. Hf isotope systematics of seamounts near the East Pacific Rise (EPR) and geodynamic implications

    NASA Astrophysics Data System (ADS)

    Zhang, Yu; Meng, Fanxue; Niu, Yaoling

    2016-10-01

    We report new Hf isotopic data for basaltic glasses from seamounts flanking the East Pacific Rise (EPR) between 5° and 15°N that have been previously analyzed for Sr-Nd-Pb isotopes as well as major and trace elements. The Hf isotopic data offer new perspectives on the petrogenesis of these samples in a broader context on mantle dynamics. The Hf isotope compositions show significant correlations with Sr-Nd-Pb isotopes and with both abundances and ratios of incompatible elements. The seamount lavas are thus best interpreted as products of melting-induced mixing in a two-component mantle. The range in composition of EPR seamount lavas cannot be generated by simple mixing of melt and melting of variably heterogeneous mantle in which enriched and depleted materials contribute equally to melting (source mixing). Instead, the trace element and isotope compositions of seamount lavas can be reproduced by melting models in which more enriched, fertile mantle component are preferentially melted during mantle upwelling. At progressively lower degrees of melting, erupted lavas are thus more enriched in incompatible trace elements, have higher 87Sr/86Sr, 208Pb/204Pb ratios and lower 143Nd/144Nd, 176Hf/177Hf ratios. The "EM1" and "pyroxenite" endmember might be the suitable enriched component. The Hf-Nd isotopic variations on global scale might result from the variations in amounts of residual continental lithospheric mantle that detached into upper mantle during continental rifting. The significant correlations of Rb/Sr vs 87Sr/86Sr, Sm/Nd vs 143Nd/144Nd and Lu/Hf vs 176Hf/177Hf give pseudochron ages of 182 ± 33 Ma, 276 ± 50 Ma and 387 ± 93 Ma, respectively. These different "ages" have no significance, but result from melting-induced mixing with the pseudochron slopes controlled by the compositions of enriched component and depleted end-member.

  15. Microstructure and Phase Stability of Single Crystal NiAl Alloyed with Hf and Zr

    NASA Technical Reports Server (NTRS)

    Locci, I. E.; Dickerson, R. M.; Garg, A.; Noebe, R. D.; Whittenberger, J. D.; Nathal, M. V.; Darolia, R.

    1996-01-01

    Six near stoichiometric, NiAl single-crystal alloys, with 0.05-1.5 at.% of Hf and Zr additions plus Si impurities, were microstructurally analyzed in the as-cast, homogenized, and aged conditions. Hafnium-rich interdendritic regions, containing the Heusler phase (Ni2AlHf), were found in all the as-cast alloys containing Hf. Homogenization heat treatments partially reduced these interdendritic segregated regions. Transmission electron microscopy (TEM) observations of the as-cast and homogenized microstructures revealed the presence of a high density of fine Hf (or Zr) and Si-rich precipitates. These were identified as G-phase, Nil6X6Si7, or as an orthorhombic NiXSi phase, where X is Hf or Zr. Under these conditions the expected Heusler phase (beta') was almost completely absent. The Si responsible for the formation of the G and NiHfSi phases is the result of molten metal reacting with the Si-containing crucible used during the casting process. Varying the cooling rates after homogenization resulted in the refinement or complete suppression of the G and NiHfSi phases. In some of the alloys studied, long-term aging heat treatments resulted in the formation of Heusler precipitates, which were more stable at the aging temperature and coarsened at the expense of the G-phase. In other alloys, long-term aging resulted in the formation of the NiXSi phase. The stability of the Heusler or NiXSi phases can be traced to the reactive element (Hf or Zr) to silicon ratio. If the ratio is high, then the Heusler phase appears stable after long time aging. If the ratio is low, then the NiHfSi phase appears to be the stable phase.

  16. Acute renal failure in liver transplant patients: Indian study.

    PubMed

    Naik, Pradeep; Premsagar, B; Mallikarjuna, M

    2015-01-01

    The acute renal failure is the frequent medical complication observed in liver transplant patients. The objective of this study was to determine the cause of acute renal failure in post liver transplant patients. A total of 70 patients who underwent (cadaveric 52, live 18) liver transplantation were categorized based on clinical presentation into two groups, namely hepatorenal failure (HRF, n = 29), and Hepatic failure (HF, n = 41). All the patients after the liver transplant had received tacrolimus, mycophenolate and steroids. We analyzed the modification of diet in renal disease, (MDRD) serum urea, creatinine and albumin before and after 5th and 30th day of liver transplant and data was categorized into survivors and non-survivors group. In HRF survivor group, serum creatinine, and urea levels were high and, albumin, MDRD were low in pre- transplant and reached to normal levels on 30th day of post transplant, and 79.3 % of patients in this group showed resumption of normal kidney function. On the contrary in HRF nonsurvivor group, we did not observed any significant difference and 20.7 % of patients showed irreversible changes after the liver transplant. In HF survivor group, 82.9 % of liver failure patients did not show any deviation in serum creatinine, urea, albumin and MDRD, whereas in HF non survivor group, 17.1 % of liver failure patients who had HCV positive before the transplant developed acute renal failure. The levels of creatinine, urea, albumin and MDRD were normal before the transplant and on day 30th, the levels of albumin and MDRD were significantly low whereas serum urea, creatinine levels were high. In conclusion, based on these observations, an diagnosis and treatment of Acute renal failure is important among the liver transplantation cases in the early postoperative period.

  17. Annealing properties of open volumes in HfSiO{sub x} and HfAlO{sub x} gate dielectrics studied using monoenergetic positron beams

    SciTech Connect

    Uedono, A.; Ikeuchi, K.; Yamabe, K.; Ohdaira, T.; Muramatsu, M.; Suzuki, R.; Hamid, A. S.; Chikyow, T.; Torii, K.; Yamada, K.

    2005-07-15

    Thin Hf{sub 0.6}Si{sub 0.4}O{sub x} and Hf{sub 0.3}Al{sub 0.7}O{sub x} films fabricated by metal-organic chemical-vapor deposition and atomic-layer-deposition techniques were characterized using monoenergetic positron beams. Measurements of the Doppler broadening spectra of annihilation radiation and the lifetime spectra of positions indicated that positrons annihilated from the trapped state by open volumes that exist intrinsically in amorphous structures of the films. For HfSiO{sub x}, the mean size of the open volumes and their size distribution decreased with increasing postdeposition annealing (PDA) temperature. For HfAlO{sub x}, although the overall behavior of the open volumes in response to annealing was similar to that for HfSiO{sub x}, PDA caused a separation of the mean size of the open volumes. When this separation occurred, the value of the line-shape parameter S increased, suggesting an oxygen deficiency in the amorphous matrix. This fragmentation of the amorphous matrix can be suppressed by decreasing the annealing time.

  18. Equilibrium and rate constants, and reaction mechanism of the HF dissociation in the HF(H2O)7 cluster by ab initio rare event simulations.

    PubMed

    Elena, Alin Marin; Meloni, Simone; Ciccotti, Giovanni

    2013-12-12

    We perform restrained hybrid Monte Carlo (MC) simulations to compute the equilibrium constant of the dissociation reaction of HF in HF(H2O)7. We find that the HF is a stronger acid in the cluster than in the bulk, and its acidity is higher at lower T. The latter phenomenon has a vibrational entropic origin, resulting from a counterintuitive balance of intra- and intermolecular terms. We find also a temperature dependence of the reactions mechanism. At low T (≤225 K) the dissociation reaction follows a concerted path, with the H atoms belonging to the relevant hydrogen bond chain moving synchronously. At higher T (300 K), the first two hydrogen atoms move together, forming an intermediate metastable state having the structure of an eigen ion (H9O4(+)), and then the third hydrogen migrates completing the reaction. We also compute the dissociation rate constant, kRP. At very low T (≤75 K) kRP depends strongly on the temperature, whereas it gets almost constant at higher T’s. With respect to the bulk, the HF dissociation in the HF(H2O)7 is about 1 order of magnitude faster. This is due to a lower free energy barrier for the dissociation in the cluster.

  19. Ti insertion in the MTe(5) (M = Zr, Hf) structure type: Hf(0.78)Ti(0.22)Te(5).

    PubMed

    Yu, Jaemin; Yun, Hoseop

    2012-03-01

    The group 5 mixed-metal telluride, Hf(0.78)Ti(0.22)Te(5) (hafnium titanium penta-telluride), is isostructural with the binary phases HfTe(5) and ZrTe(5) and forms a layered structure extending parallel to (010). The layers are made up from chains of bicapped metal-centered trigonal prisms and zigzag Te chains. The metal site (site symmetry m2m) is occupied by statistically disordered Hf [78.1 (5)%] and Ti [21.9 (5)%]. In addition to the regular Te-Te pair [2.7448 (13) Å] forming the short base of the equilateral triangle of the trigonal prism, an inter-mediate Te⋯Te separation [2.9129 (9) Å] is also found. The classical charge balance of the compound can be described as [M(4+)][Te(2-)][Te(2) (2-)][Te(2) (0)] (M = Hf, Ti). The individual metal content can vary in different crystals, apparently forming a random substitutional solid solution (Hf(1-x)Ti(x))Te(5), with 0.15 ≤ x ≤ 0.22.

  20. Continuous internal counterpulsation as a bridge to recovery in acute and chronic heart failure

    PubMed Central

    Kontogiannis, Christos D; Malliaras, Konstantinos; Kapelios, Chris J; Mason, Jay W; Nanas, John N

    2016-01-01

    Cardiac recovery from cardiogenic shock (CS) and end-stage chronic heart failure (HF) remains an often insurmountable therapeutic challenge. The counterpulsation technique exerts numerous beneficial effects on systemic hemodynamics and left ventricular mechanoenergetics, rendering it attractive for promoting myocardial recovery in both acute and chronic HF. Although a recent clinical trial has questioned the clinical effectiveness of short-term hemodynamic support with intra-aortic balloon pump (IABP, the main representative of the counterpulsation technique) in CS complicating myocardial infarction, the issue remains open to further investigation. Moreover, preliminary data suggest that long-term IABP support in patients with end-stage HF is safe and may mediate recovery of left- or/and right-sided cardiac function, facilitating long-term weaning from mechanical support or enabling the application of other permanent, life-saving solutions. The potential of long-term counterpulsation could possibly be enhanced by implementation of novel, fully implantable counterpulsation devices. PMID:27011909

  1. Crystal structure of Na2HfSi2O7 by Rietveld refinement.

    PubMed

    Massoni, Nicolas; Chevreux, Pierrick

    2016-10-01

    The structure of triclinic disodium hafnium disilicate, Na2HfSi2O7, has been determined by laboratory powder X-ray diffraction and refined by the Rietveld refinement. The structure is a framework made of alternate layers of HfO6 octa-hedra and SiO4 tetra-hedra linked by common O atoms. Sodium atoms are located in the voids of the framework, aligned into tunnels along the [010] direction. Na2HfSi2O7 is isostructural with the parakeldyshite Na2ZrSi2O7 phase.

  2. Artificial Ionization and UHF Radar Response Associated with HF Frequencies near Electron Gyro-Harmonics (Invited)

    NASA Astrophysics Data System (ADS)

    Watkins, B. J.; Fallen, C. T.; Secan, J. A.

    2013-12-01

    We present new results from O-mode ionospheric heating experiments at the HAARP facility in Alaska to demonstrate that the magnitude of artificial ionization production is critically dependent on the choice of HF frequency near gyro-harmonics. For O-mode heating in the lower F-region ionosphere, typically about 200 km altitude, artificial ionization enhancements are observed in the lower ionosphere (about 150 - 220 km) and also in the topside ionosphere above about 500 km. Lower ionosphere density enhancements are inferred from HF-enhanced ion and plasma-line signals observed with UHF radar. Upper ionospheric density enhancements have been observed with TEC (total electron content) experiments by monitoring satellite radio beacons where signal paths traverse the HF-modified ionosphere. Both density enhancements and corresponding upward plasma fluxes have also been observed in the upper ionosphere via in-situ satellite observations. The data presented focus mainly on observations near the third and fourth gyro-harmonics. The specific values of the height-dependent gyro-harmonics have been computed from a magnetic model of the field line through the HF heated volume. Experiments with several closely spaced HF frequencies around the gyro-harmonic frequency region show that the magnitude of the lower-ionosphere artificial ionization production maximizes for HF frequencies about 1.0 - 1.5 MHz above the gyro-harmonic frequency. The response is progressively larger as the HF frequency is increased in the frequency region near the gyro-harmonics. For HF frequencies that are initially greater than the gyro-harmonic value the UHF radar scattering cross-section is relatively small, and non-existent or very weak signals are observed; as the signal returns drop in altitude due to density enhancements the HF interaction region passes through lower altitudes where the HF frequency is less than the gyro-harmonic value, for these conditions the radar scattering cross-section is

  3. PARTITION COEFFICIENTS OF Hf, Zr, AND REE BETWEEN PHENOCRYSTS AND GROUNDMASSES.

    USGS Publications Warehouse

    Fujimaki, Hirokazu; Tatsumoto, Mitsunobu; Aoki, Ken-ichiro

    1984-01-01

    Partition coefficients of Hf, Zr, and REE between olivine, orthopyroxene, clinopyroxene, plagioclase, garnet, amphibole, ilmenite, phlogopite, and liquid are presented. Samples consist of megacrysts in kimberlite, phenocrysts in alkaline basalts, tholeiitic basalts and andesitic to dacitic rocks, and synthetic garnet and clinopyroxene in Hawaiian tholeiites. The Hf-Lu and Zr-Lu elemental fractionations are as large as the Lu-Sm or Lu-Nd fractionation. The Hf and Zr partition coefficients between mafic phenocrysts and liquids are smaller than the Lu partition coefficients, but are similar to the Nd or Sm partition coefficients.

  4. Constraints from loess on the Hf-Nd isotopic composition of the upper continental crust

    NASA Astrophysics Data System (ADS)

    Chauvel, Catherine; Garçon, Marion; Bureau, Sarah; Besnault, Adeline; Jahn, Bor-ming; Ding, Zhongli

    2014-02-01

    Knowledge of the average composition of the upper continental crust is crucial to establish not only how it formed but also when. While well constrained averages have been suggested for its major and trace element composition, no values exist for its Nd and Hf isotopic compositions even though radiogenic isotopic systems provide valuable information on its average model age. Here we present Nd and Hf isotopic data determined on a large number of loess deposits from several continents. We demonstrate that these deposits have very uniform Nd and Hf isotopic compositions. We obtain an average Nd isotopic composition that is similar to previous estimates for the upper continental crust (εNd=-10.3±1.2(1σ)) and we establish a new Hf average value at εHf=-13.2±2(1σ). This average falls on the “Terrestrial Array”, demonstrating that the two parent-daughter ratios are not decoupled during crust formation. Trace element data acquired on the same set of samples allow us to calculate an average 147Sm/144Nd ratio for the upper continental crust: 0.1193±0.0026, a value slightly higher than previous estimates. Based on the relationship between Sm/Nd and Nd isotopes, we estimate the average Nd extraction age of upper continental crust from the depleted mantle at TDM(Nd)=1.82±0.07 Ga. This model age is entirely consistent with previous suggestions made for example by Goldstein et al. (1984). Assuming that for each individual sample, the Hf model age cannot be younger than the Nd model age, our new Nd-Hf isotopic data provide a value for the very poorly known 176Lu/177Hf ratio of the upper crust. Our estimate is 176Lu/177Hf = 0.0125 ± 0.0018, a value significantly lower than commonly used values (0.0150-0.0159; Griffin et al., 2002; Goodge and Vervoort, 2006; Hawkesworth et al., 2010) but higher than Rudnick and Gao's (2003) estimate of 0.0083. The impact of our new 176Lu/177Hf ratio on crustal model ages of zircon populations is not simple to evaluate but the Hf model

  5. Heterogeneous conversion of COF2 to HF in polar stratospheric clouds

    NASA Technical Reports Server (NTRS)

    Wofsy, Steven C.; Yatteau, John H.; Salawitch, Ross J.; Mcelroy, Michael B.; Toon, Geoffrey C.

    1990-01-01

    It is argued that the reaction COF2 + H2O - 2HF + CO2 should proceed on surfaces of polar stratospheric clouds, based on laboratory evidence for this reaction in condensed phase and on analysis of column observations of HF during the Airborne Arctic Stratospheric Expedition. If the hypothesis is confirmed, observations of COF2 and HF could provide unambiguous indication of heterogeneous processing of polar air, and could help elucidate the influence of heterogeneous chemistry on concentrations of HCl, ClNO3, and chlorine oxide radicals.

  6. Graphene contacts to a HfSe2/SnS2 heterostructure.

    PubMed

    Su, Shanshan; Das, Protik; Ge, Supeng; Lake, Roger K

    2017-02-14

    Two-dimensional (2D) heterostructures and all-2D contacts are of high interest for electronic device applications, and the SnS2/HfSe2 bilayer heterostructure with graphene contacts has some unique, advantageous properties. The SnS2/HfSe2 heterostructure is interesting because of the strong intermixing of the two conduction bands and the large work function of the SnS2. The band lineup of the well separated materials indicates a type II heterostructure, but the conduction band minimum of the SnS2/HfSe2 bilayer is a coherent superposition of the orbitals from the two layers with a spectral weight of 60% on the SnS2 and 40% on the HfSe2 for AA stacking. These relative weights can be either increased or reversed by an applied vertical field. A 3×3 supercell of graphene and a 2×2 supercell of SnS2/HfSe2 have a lattice mismatch of 0.1% and both the SnS2/HfSe2 conduction band at M and the graphene Dirac point at K are zone-folded to Γ. Placing graphene on the SnS2/HfSe2 bilayer results in large n-type charge transfer doping of the SnS2/HfSe2 bilayer, on the order of 10(13)/cm(2), and the charge transfer is accompanied by a negative Schottky barrier contact for electron injection from the graphene into the SnS2/HfSe2 bilayer conduction band. Binding energies and the anti-crossing gaps of the graphene and the SnS2/HfSe2 electronic bands both show that the coupling of graphene to the HfSe2 layer is significantly larger than its coupling to the SnS2 layer. A tunneling Hamiltonian estimate of the contact resistance of the graphene to the SnS2/HfSe2 heterostructure predicts an excellent low-resistance contact.

  7. Crystal structure of Na2HfSi2O7 by Rietveld refinement

    PubMed Central

    Massoni, Nicolas; Chevreux, Pierrick

    2016-01-01

    The structure of triclinic disodium hafnium disilicate, Na2HfSi2O7, has been determined by laboratory powder X-ray diffraction and refined by the Rietveld refinement. The structure is a framework made of alternate layers of HfO6 octa­hedra and SiO4 tetra­hedra linked by common O atoms. Sodium atoms are located in the voids of the framework, aligned into tunnels along the [010] direction. Na2HfSi2O7 is isostructural with the parakeldyshite Na2ZrSi2O7 phase. PMID:27746936

  8. Graphene contacts to a HfSe2/SnS2 heterostructure

    NASA Astrophysics Data System (ADS)

    Su, Shanshan; Das, Protik; Ge, Supeng; Lake, Roger K.

    2017-02-01

    Two-dimensional (2D) heterostructures and all-2D contacts are of high interest for electronic device applications, and the SnS2/HfSe2 bilayer heterostructure with graphene contacts has some unique, advantageous properties. The SnS2/HfSe2 heterostructure is interesting because of the strong intermixing of the two conduction bands and the large work function of the SnS2. The band lineup of the well separated materials indicates a type II heterostructure, but the conduction band minimum of the SnS2/HfSe2 bilayer is a coherent superposition of the orbitals from the two layers with a spectral weight of 60% on the SnS2 and 40% on the HfSe2 for AA stacking. These relative weights can be either increased or reversed by an applied vertical field. A 3 ×3 supercell of graphene and a 2 ×2 supercell of SnS2/HfSe2 have a lattice mismatch of 0.1% and both the SnS2/HfSe2 conduction band at M and the graphene Dirac point at K are zone-folded to Γ . Placing graphene on the SnS2/HfSe2 bilayer results in large n-type charge transfer doping of the SnS2/HfSe2 bilayer, on the order of 1013/cm2, and the charge transfer is accompanied by a negative Schottky barrier contact for electron injection from the graphene into the SnS2/HfSe2 bilayer conduction band. Binding energies and the anti-crossing gaps of the graphene and the SnS2/HfSe2 electronic bands both show that the coupling of graphene to the HfSe2 layer is significantly larger than its coupling to the SnS2 layer. A tunneling Hamiltonian estimate of the contact resistance of the graphene to the SnS2/HfSe2 heterostructure predicts an excellent low-resistance contact.

  9. Structural and thermal properties of Cu-Hf-Ti bulk amorphous alloys

    NASA Astrophysics Data System (ADS)

    Rontó, V.; Nagy, E.; Svéda, M.; Roósz, A.; Tranta, F.

    2009-01-01

    Cu-Hf-Ti amorphous alloys are high strength and wear resistant materials. Master alloys of Cu57.5Hf27.5Ti15 and Cu57.5Hf25Ti17.5 ternary alloys have been prepared by arc melting, and wedge and rod shaped samples have been cast by centrifugal casting. Liquidus and solidus temperatures of the alloys were determined by DTA. The fully amorphous size was determined by X-ray diffraction. Thermodynamic properties of the amorphous alloys were studied by DSC measurements and Kissinger analyses were performed.

  10. Processing and mechanical properties of materials in the Hf-N system.

    SciTech Connect

    Wuchina, E.; Opeka, M.; Gutierrez-Mora, F.; Koritala, R.; Goretta, K. C.; Routbort, J. L.; Energy Technology; Naval Surface Warefare Center

    2002-01-01

    Samples of hexagonal {alpha}-Hf containing up to 30 at.% N in solid solution were made by a solid-state reaction. The brittle-to-ductile transition temperature increased as the %N increased. Steady-state compressive deformation has been measured from 20 to 1000 C. The data for pure Hf could be fit using a threshold stress with a stress exponent of 5. The stress exponent of the Hf-N solid solution materials was between 5 and 8. The experiments could be interpreted on the basis of dislocation-controlled plasticity, with N acting as classical solid-solution hardening solutes. Transmission electron microscopy supported this interpretation.

  11. Simulation of a two-frequency cw chemical HF-HBr laser

    SciTech Connect

    Aleksandrov, B P; Katorgin, B I; Stepanov, A A

    2008-10-31

    An autonomous cw chemical HF-HBr laser emitting simultaneously at {approx}2.7 {mu}m (HF molecules) and {approx}4.2 {mu}m (HBr molecules) is studied numerically by using complete Navier-Stokes equations. It is shown that the output power of the HBr laser per unit area of the nozzle array can achieve {approx}20 W cm{sup -2} for the laser region length {approx}20 cm. The relation between the radiation intensities emitted by HF and HBr molecules is controlled by diluting the secondary fuel by bromine. (lasers)

  12. Cancer Antigen 125 is Associated with Length of Stay in Patients with Acute Heart Failure

    PubMed Central

    Kurt, Recep; Beton, Osman; Zorlu, Ali; Yucel, Hasan; Gunes, Hakan; Oguz, Didem; Yilmaz, Mehmet Birhan

    2017-01-01

    Length of stay is the primary driver of heart-failure hospitalization costs. Because cancer antigen 125 has been associated with poor morbidity and mortality rates in heart failure, we investigated the relationship between admission cancer antigen 125 levels and lengths of stay in heart-failure patients. A total of 267 consecutive patients (184 men, 83 women) with acute decompensated heart failure were evaluated prospectively. The median length of stay was 4 days, and the patients were classified into 2 groups: those with lengths of stay ≤4 days and those with lengths of stay >4 days. Patients with longer lengths of stay had a significantly higher cancer antigen 125 level of 114 U/mL (range, 9–298 U/mL) than did those with a shorter length of stay (19 U/mL; range; 3–68) (P <0.001). The optimal cutoff level of cancer antigen 125 in the prediction of length of stay was >48 U/mL, with a specificity of 95.8% and a sensitivity of 96% (area under the curve, 0.979; 95% confidence interval [CI], 0.953–0.992). In the multivariate logistic regression model, cancer antigen 125 >48 U/mL on admission (odds ratio=4.562; 95% CI, 1.826–11.398; P=0.001), sodium level (P<0.001), creatinine level (P=0.009), and atrial fibrillation (P=0.015) were also associated with a longer length of stay after adjustment for variables found to be statistically significant in univariate analysis and correlated with cancer antigen 125 level. In addition, it appears that in a cohort of patients with acute decompensated heart failure, cancer antigen 125 is independently associated with prolonged length of stay. PMID:28265209

  13. Acute Vestibulopathy

    PubMed Central

    Cha, Yoon-Hee

    2011-01-01

    The presentation of acute vertigo may represent both a common benign disorder or a life threatening but rare one. Familiarity with the common peripheral vestibular disorders will allow the clinician to rapidly “rule-in” a benign disorder and recognize when further testing is required. Key features of vertigo required to make an accurate diagnosis are duration, chronicity, associated symptoms, and triggers. Bedside tests that are critical to the diagnosis of acute vertigo include the Dix-Hallpike maneuver and canalith repositioning manuever, occlusive ophthalmoscopy, and the head impulse test. The goal of this review is to provide the clinician with the clinical and pathophysiologic background of the most common disorders that present with vertigo to develop a logical differential diagnosis and management plan. PMID:23983835

  14. Acute Blindness.

    PubMed

    Meekins, Jessica M

    2015-09-01

    Sudden loss of vision is an ophthalmic emergency with numerous possible causes. Abnormalities may occur at any point within the complex vision pathway, from retina to optic nerve to the visual center in the occipital lobe. This article reviews specific prechiasm (retina and optic nerve) and cerebral cortical diseases that lead to acute blindness. Information regarding specific etiologies, pathophysiology, diagnosis, treatment, and prognosis for vision is discussed.

  15. Wet BNP, fluid and hemodynamic status at discharge in acute heart failure.

    PubMed

    Parrinello, Gaspare; Torres, Daniele; Paterna, Salvatore; Di Pasquale, Pietro; Licata, Giuseppe

    2010-11-19

    We comment the noteworthy results of Pimenta et al. concerning the significance of discharge BNP levels in acute HF patients. The innovation of Pimento's study is the systematic research of the potential relationship between BNP and clinical and hemodynamic parameters. We focused the attention on the importance of wet "BNP" in managing HF and its ability to reflect congestion and multiple underlying patho-physiological disturbances. The first observation, regarding the statistical order, underlines the importance of renal insufficiency at discharge in genesis of higher BNP levels. Secondly, we note that the relationship between natriuretic peptides and the non-invasive measurement of the fluid status assessed by bioelectrical impedance analysis was already demonstrated. Thirdly, we comment on the potential therapeutical implication of the verified relationship between BNP and albumin levels and we argue on the clinical utility of the albumin supplementation or hypertonic solutions in unstable HF management due to their oncotic power. Fourthly, we wish to further examine the role of central volemia. We underline that some studies had demonstrated that systemic congestion may be a mirror of central congestion and may also influence these levels alone in acute and also chronic HF patients. We believe that a concealed or poorly-assessed accumulation of systemic fluid is of crucial importance in managing HF, which frequently remains undiagnosed or inappropriately treated, thus requiring recurrent hospital readmission and disease progression. Furthermore not only BNP at discharge but also bioimpedance detection may be helpful to discover misdiagnosed congestion. We are of the opinion that, in cases of hospitalized HF and thereafter in ambulatory setting, the achievement and, then, maintenance of dry-wet tailoring diuretics, fluid and sodium intake is the key approach leading to a euvolemic status, a lowering of the NYHA class and an improvement in cardiac hemodynamics

  16. Rationale, Design, Methodology and Hospital Characteristics of the First Gulf Acute Heart Failure Registry (Gulf CARE)

    PubMed Central

    Sulaiman, Kadhim J.; Panduranga, Prashanth; Al-Zakwani, Ibrahim; Alsheikh-Ali, Alawi; Al-Habib, Khalid; Al-Suwaidi, Jassim; Al-Mahmeed, Wael; Al-Faleh, Husam; El-Asfar, Abdelfatah; Al-Motarreb, Ahmed; Ridha, Mustafa; Bulbanat, Bassam; Al-Jarallah, Mohammed; Bazargani, Nooshin; Asaad, Nidal; Amin, Haitham

    2014-01-01

    Background: There is paucity of data on heart failure (HF) in the Gulf Middle East. The present paper describes the rationale, design, methodology and hospital characteristics of the first Gulf acute heart failure registry (Gulf CARE). Materials and Methods: Gulf CARE is a prospective, multicenter, multinational registry of patients >18 year of age admitted with diagnosis of acute HF (AHF). The data collected included demographics, clinical characteristics, etiology, precipitating factors, management and outcomes of patients admitted with AHF. In addition, data about hospital readmission rates, procedures and mortality at 3 months and 1-year follow-up were recorded. Hospital characteristics and care provider details were collected. Data were entered in a dedicated website using an electronic case record form. Results: A total of 5005 consecutive patients were enrolled from February 14, 2012 to November 13, 2012. Forty-seven hospitals in 7 Gulf States (Oman, Saudi Arabia, Yemen, Kuwait, United Gulf Emirates, Qatar and Bahrain) participated in the project. The majority of hospitals were community hospitals (46%; 22/47) followed by non-University teaching (32%; 15/47 and University hospitals (17%). Most of the hospitals had intensive or coronary care unit facilities (93%; 44/47) with 59% (28/47) having catheterization laboratory facilities. However, only 29% (14/47) had a dedicated HF clinic facility. Most patients (71%) were cared for by a cardiologist. Conclusions: Gulf CARE is the first prospective registry of AHF in the Middle East, intending to provide a unique insight into the demographics, etiology, management and outcomes of AHF in the Middle East. HF management in the Middle East is predominantly provided by cardiologists. The data obtained from this registry will help the local clinicians to identify the deficiencies in HF management as well as provide a platform to implement evidence based preventive and treatment strategies to reduce the burden of HF in

  17. Large ionospheric disturbances produced by the HAARP HF facility

    NASA Astrophysics Data System (ADS)

    Bernhardt, Paul A.; Siefring, Carl L.; Briczinski, Stanley J.; McCarrick, Mike; Michell, Robert G.

    2016-07-01

    The enormous transmitter power, fully programmable antenna array, and agile frequency generation of the High Frequency Active Auroral Research Program (HAARP) facility in Alaska have allowed the production of unprecedented disturbances in the ionosphere. Using both pencil beams and conical (or twisted) beam transmissions, artificial ionization clouds have been generated near the second, third, fourth, and sixth harmonics of the electron gyrofrequency. The conical beam has been used to sustain these clouds for up to 5 h as opposed to less than 30 min durations produced using pencil beams. The largest density plasma clouds have been produced at the highest harmonic transmissions. Satellite radio transmissions at 253 MHz from the National Research Laboratory TACSat4 communications experiment have been severely disturbed by propagating through artificial plasma regions. The scintillation levels for UHF waves passing through artificial ionization clouds from HAARP are typically 16 dB. This is much larger than previously reported scintillations at other HF facilities which have been limited to 3 dB or less. The goals of future HAARP experiments should be to build on these discoveries to sustain plasma densities larger than that of the background ionosphere for use as ionospheric reflectors of radio signals.

  18. LU-HF Age of Martian Meteorite Larkman Nunatek 06319

    NASA Technical Reports Server (NTRS)

    Shafer, J. T.; Brandon, A. D.; Lapen, T. J.; Righter, M.; Beard, B.; Peslier, A. H.

    2009-01-01

    Lu-Hf isotopic data were collected on mineral separates and bulk rock powders of LAR 06319, yielding an age of 197+/- 29 Ma. Sm-Nd isotopic data and in-situ LA-ICP-MS data from a thin section of LAR 06319 are currently being collected and will be presented at the 2009 LPSC. These new data for LAR 06319 extend the existing data set for the enriched shergottite group. Martian meteorites represent the only opportunity for ground truth investigation of the geochemistry of Mars [1]. At present, approximately 80 meteorites have been classified as Martian based on young ages and distinctive isotopic signatures [2]. LAR 06319 is a newly discovered (as part of the 2006 ANSMET field season) martian meteorite that represents an important opportunity to further our understanding of the geochemical and petrological constraints on the origin of Martian magmas. Martian meteorites are traditionally categorized into the shergottite, nakhlite, and chassignite groups. The shergottites are further classified into three distinct isotopic groups designated depleted, intermediate, and enriched [3,4] based on the isotope systematics and compositions of their source(s).

  19. Bursts of HF radio noises after irregularities of solar wind

    NASA Astrophysics Data System (ADS)

    Dudnik, O. V.; Malykhina, T. V.

    We present analyses of HF radio emission spectra of magnetospheric origin, at frequencies of 150 and 500 MHz, collected with ground-based antennae at middle latitudes ( L=2) during the second half of 1999. We discover a large occurrence of short-time-scale (1-10 s) sporadic radio bursts during active solar periods. To identify the source of these bursts, we associate their occurrence and perform correlations with solar wind parameters and energetic particle fluxes in interplanetary space and in the outer magnetosphere. Solar wind parameters and energetic ion fluxes in interplanetary space are provided by the ACE satellite. GOES8 and GOES10 satellites provide electron fluxes with energy E>2 MeV at geosynchronous orbit. These data are analyzed in order to show a correlation between particle fluxes and high amplitude radio bursts. There is a delay between the initiations of high-amplitude, short-term, sporadic radio bursts (at a frequency 150 MHz) and the arrival of high-speed solar wind streams at Earth's magnetosphere. The temporal delay of a few hours from the start of these features in the temporal distribution of electron fluxes at L=6.6 is shown, too. We suggest the possibility that the sources of radio bursts are located in the inner parts of magnetosphere.

  20. Low modulus Ti-Nb-Hf alloy for biomedical applications.

    PubMed

    González, M; Peña, J; Gil, F J; Manero, J M

    2014-09-01

    β-Type titanium alloys with a low elastic modulus are a potential strategy to reduce stress shielding effect and to enhance bone remodeling in implants used to substitute failed hard tissue. For biomaterial application, investigation on the mechanical behavior, the corrosion resistance and the cell response is required. The new Ti25Nb16Hf alloy was studied before and after 95% cold rolling (95% C.R.). The mechanical properties were determined by tensile testing and its corrosion behavior was analyzed by potentiostatic equipment in Hank's solution at 37°C. The cell response was studied by means of cytotoxicity evaluation, cell adhesion and proliferation measurements. The stress-strain curves showed the lowest elastic modulus (42GPa) in the cold worked alloy and high tensile strength, similar to that of Ti6Al4V. The new alloy exhibited better corrosion resistance in terms of open circuit potential (EOCP), but was similar in terms of corrosion current density (iCORR) compared to Ti grade II. Cytotoxicity studies revealed that the chemical composition of the alloy does not induce cytotoxic activity. Cell studies in the new alloy showed a lower adhesion and a higher proliferation compared to Ti grade II presenting, therefore, mechanical features similar to those of human cortical bone and, simultaneously, a good cell response.

  1. Anomalous phenomena on HF radio paths during geomagnetic disturbances

    NASA Astrophysics Data System (ADS)

    Blagoveshchenskii, D. V.

    2016-07-01

    We analyze ionospheric oblique sounding data on three high-latitude and one high-latitude-midlatitude HF radio paths for February 15 and 16, 2014, when two substorms and one magnetic storm occurred. We investigate cases of anomalous propagation of signals: their reflection from sporadic layer Es, lateral reflections, type "M" or "N" modes, the presence of traveling ionospheric disturbances, and the diffusivity of signals and triplets. The most significant results are the following. In geomagnetically undisturbed times, sporadic Es-layers with reduced maximum observed frequencies (MOF Es) on three high-latitude paths were observed in both days. The values of MOF Es during disturbances are large, which leads to the screening of other oblique sounding signals reflected from the ionosphere. On all four paths, the most frequently traveling ionospheric disturbances due to the terminator were observed in quiet hours from 03:00 to 15:00 UT on the first day and from 06:00 to 13:00 UT on the second day of the experiment. In addition, both the sunset terminator and the magnetic storm on the high-latitude-mid-latitude path were found to generate traveling ionospheric disturbances jointly. No such phenomenon was found on high-latitude paths.

  2. Lu-Hf and Sm-Nd Isotopic Studies of Shergottites and Nakhlites: Implications for Martian Mantle Sources

    NASA Technical Reports Server (NTRS)

    Debaille, V.; Yin, Q.-Z.; Brandon, A. D.; Jacobsen, B.; Treiman, A. H.

    2007-01-01

    We present a new Lu-Hf and Sm-Nd isotope systematics study of four enriched shergottites (Zagami, Shergotty, NWA856 and Los Angeles), and three nakhlites (Nakhla, MIL03346 and Yamato 000593) in order to further understand processes occurring during the early differentiation of Mars and the crystallization of its magma ocean. Two fractions of the terrestrial petrological analogue of nakhlites, the Archaean Theo's flow (Ontario, Canada) were also measured. The coupling of Nd and Hf isotopes provide direct insights on the mineralogy of the melt sources. In contrast to Sm/Nd, Lu/Hf ratios can be very large in minerals such as garnet. Selective partial melting of garnet bearing mantle sources can therefore lead to characteristic Lu/Hf signatures that can be recognized with Hf-176/Hf-177Hf ratios.

  3. Effects of Modified Precursor Solution on Microstructure of (Y,Yb)MnO3/HfO2/Si

    NASA Astrophysics Data System (ADS)

    Suzuki, Kazuyuki; Kato, Kazumi

    2007-10-01

    Ferroelectric/insulator/silicon structures were prepared using (Y,Yb)MnO3 films as ferroelectrics and HfO2 thin films as insulators through alkoxy-derived precursor solutions. The HfO2 solution was chemically modified in order to decrease the number of heating cycles required. The HfO2 films prepared using a partially hydrolyzed alkoxide solution had a uniform structure. From the results of measurements of the roughness level and refractive index of the HfO2 films, the partial hydrolysis of the HfO2 solution was found to be effective for the formation of a uniform microstructure in a thin insulator film. (Y,Yb)MnO3/HfO2/Si structures were constructed using the resultant HfO2 thin films prepared using the modified solutions.

  4. Effects of C and Hf concentration on phase relations and microstructure of a wrought powder-metallurgy superalloy

    NASA Technical Reports Server (NTRS)

    Miner, R. V., Jr.

    1977-01-01

    NASA IIB-11, a candidate alloy for advanced temperature turbine engine disks, and four modifications with varying C and Hf concentrations were produced from prealloyed powders. Several notable effects of C and Hf concentration in the alloys were observed. Both the amount of the gamma-prime phase and its solvus temperature increased with decreasing C, but only the gamma-prime solvus was affected by Hf, increasing with increasing Hf. Hf also promoted a cellular gamma-prime precipitation. Hf was, however, about equally distributed between gamma-prime and gamma. Hf and C both affected the carbides formed. Increasing both promoted formation of an MC relative to that of an M6C.

  5. Reactive scattering of F+HD -> HF(v,J)+D: HF(v,J) nascent product state distributions and evidence for quantum transition state resonances

    SciTech Connect

    Harper, Warren W. ); Nizkorodov, Sergey A.; Nesbitt, David

    2001-12-01

    Single collision reactive scattering dynamics of F+ HDHF(v,J)+ D have been investigated exploiting high-resolution (0.0001 cm?1) infrared laser absorption for quantum state resolved detection of nascent HF(v,J) product states. State resolved Doppler profiles are recorded for a series of HF rovibrational transitions and converted into state resolved fluxes via density-to-flux analysis, yielding cross-section data for relative formation of HF(v,J) at Ecom0.6(2), 1.0(3), 1.5(3), and 1.9(4) kcal/mol. State resolved HF(v,J) products at all but the lowest collision energy exhibit Boltzmann-type populations, characteristic of direct reactive scattering dynamics. At the lowest collision energy[Ecom0.6(2) kcal/mol], however, the HF(v= 2,J) populations behave quite anomalously, exhibiting a nearly''flat'' distribution out to J11 before dropping rapidly to zero at the energetic limit. These results provide strong experimental support for quantum transition state resonance dynamics near Ecom0.6 kcal /mol corresponding classically to H atom chattering between the F and D atoms, and prove to be in remarkably quantitative agreement with theoretical wave packet predictions by Skodje et al.[J. Chem. Phys. 112, 4536 (2000)]. These fully quantum state resolved studies therefore nicely complement the recent crossed beam studies of Dong et al.[J. Chem. Phys. 113, 3633 (2000)], which confirm the presence of this resonance via angle resolved differential cross-section measurements. The observed quantum state distributions near threshold also indicate several rotational states in the HF(v= 3) vibrational manifold energetically inaccessible to F(2P3/2) reagent, but which are consistent with a minor (5%) nonadiabatic contribution from spin?orbit excited F*(2P1/2).?2002 American Institute of Physics.

  6. Development of Hf(4+)-immobilized polydopamine-coated magnetic graphene for highly selective enrichment of phosphopeptides.

    PubMed

    Lin, Haizhu; Deng, Chunhui

    2016-01-01

    In this work, we first designed and synthesized an IMAC material with Hf(4+) immobilized on polydopamine-coated magnetic graphene and applied it to phosphopeptides enrichment successfully. The newly prepared material gathered the advantages of large specific surface area of graphene, good hydrophilicity and biocompatibility of polydopamine and superparamagnetism of Fe3O4. We investigated the performance of Hf(4+)-immobilized polydopamine-coated magnetic graphene (denoted as magG@PDA-Hf(4+)) in phosphopeptides enrichment and the results showed high selectivity and sensitivity of the new material. Finally, we successfully applied magG@PDA-Hf(4+) to phosphopeptides enrichment from non-fat milk digests and human serum, further demonstrating excellent performance of this new material in phosphopeptides enrichment.

  7. Modulation of auroral electrojet currents using dual HF beams with ELF phase offset

    NASA Astrophysics Data System (ADS)

    Golkowski, M.; Cohen, M.; Moore, R. C.

    2012-12-01

    The modulation of naturally occuring ionospheric currents with high power radio waves in the high frequency (HF, 3-10 MHz) band is a well known technique for generation of extremely low frequency (ELF, 3-3000 Hz) and very low frequency (VLF, 3-30 kHz) waves. We use the heating facility of the High Frequency Active Auroral Research Program (HAARP) to investigate the effect of using dual HF beams with an ELF/VLF phase offset between the modulation waveforms. Experiments with offset HF beams confirm the model of independent ELF/VLF sources. Experiments with co-located HF beams exhibit interaction between the first and second harmonics of the modulated tones when square and sine wave modulation waveforms are employed. Using ELF/VLF phase offsets for co-loacted beams is also shown to be a potential diagnostic for the D-region ionospheric profile.

  8. Interfacial SiO2 scavenging kinetics in HfO2 gate stack

    NASA Astrophysics Data System (ADS)

    Li, Xiuyan; Nishimura, Tomonori; Toriumi, Akira

    2016-11-01

    In this paper, Si and oxygen diffusions as well as SiO2 reduction reaction in HfO2/SiO2/Si stacks are examined in detail for fully understanding the SiO2-IL scavenging process. A 29Si isotope tracing experiment confirms that Si in SiO2-IL is mostly emitted from the HfO2 surface. In addition, the reaction of oxygen from SiO2 with VO in HfO2 is suggested. Furthermore, it is reported that the Si substrate is not changed at all in the SiO2-IL scavenging by simultaneously comparing a Si surface between with and without scavenged parts. Based on these results, a kinetic model for the SiO2-IL scavenging in HfO2/SiO2/Si stacks is proposed.

  9. Lu-Hf total-rock isochron for the eucrite meteorites

    NASA Technical Reports Server (NTRS)

    Patchett, P. J.; Tatsumoto, M.

    1980-01-01

    The isotope Lu-176 (2.6% of natural lutetium) decays by beta(-) to Hf-176, with a long half life. The first Lu-Hf isochron is presented. The eucrite meteorites, a suite of planetary igneous rocks of known age, 4,550 Myr, define a 10-point total-rock isochron with a slope of 0.0934 + or - 40, leading to a value of 3.53 + or - 0.14 x 10 to the 10th yr for the beta(-) decay half life of Lu-176. The isochron intercept of 0.27973 + or - 12 gives the initial Hf-176/Hf-177 for the inner solar system at the time of accretion.

  10. Ferroelectric modulation of terahertz waves with graphene/ultrathin-Si:HfO2/Si structures

    NASA Astrophysics Data System (ADS)

    Jiang, Ran; Han, Zuyin; Sun, Weideng; Du, Xianghao; Wu, Zhengran; Jung, Hyung-Suk

    2015-10-01

    Ferroelectric-field-effect-tunable modulation of terahertz waves in graphene/Si:HfO2/Si stack structure was observed. The modulation shows distinct behaviors when the samples under different gate polarities. At a negative voltage, a transmission modulation depth up to ˜74% was present without depending on the photo illumination power, whereas, at a positive voltage, the modulation of Thz wave shows dependence on the illumination power, which is ascribed to the creation/elimination of an extra barrier in Si layer in response to the polarization in the ferroelectric Si:HfO2 layer. Considering the good compatibility of HfO2 on Si-based semiconductor process, the ferroelectricity layer of Si:HfO2 may open up an avenue for the tunable modulation of Thz wave.

  11. In situ characterization of initial growth of HfO{sub 2}

    SciTech Connect

    Wang, L.; Chu, Paul K.; Xue, K.; Xu, J. B.

    2009-01-19

    The initial growth of HfO{sub 2} on Si (111) is monitored in situ by ultrahigh vacuum (UHV) scanning probe microscopy. UHV scanning tunneling microscopy and UHV atomic force microscopy reveal the topography of HfO{sub 2} films in the initial stage. The chemical composition is further confirmed by x-ray photoelectron spectroscopy. Scanning tunneling spectroscopy is utilized to inspect the evolution of the bandgap. When the film thickness is less than 0.6 nm, the bandgap of HfO{sub 2} is not completely formed. A continuous usable HfO{sub 2} film with thickness of about 1.2 nm is presented in this work.

  12. Spectroscopic requirements for HALOE: An analysis of the HCl and HF channels

    NASA Technical Reports Server (NTRS)

    Rinsland, C. P.; Smith, M. A. H.; Park, J. H.; Harvey, G. A.; Russell, J. M., III; Richardson, D. J.

    1982-01-01

    Spectral line parameters that have absorption features within the HCl and HF channels of the Halogen Occultation Experiment (HALOE) were evaluated. Line positions and identification of stratospheric and solar absorption features in both channels are presented based on an analysis of high-resolution, balloon-borne solar occultation spectra. For the relevant HCl and HF lines and for transitions of the interfering species, the accuracy of the following spectral parameters was assessed: line positions, line strengths, lower state energies, air-broadened collisional half-widths, and temperature dependence of the air-broadened half-widths. In addition, since the HALOE instrument and calibration cells are filled with mixtures of HCl in N2 and HF in N2, the self-broadened and N2-broadened HF and HCl half-widths were also considered.

  13. 6. Historic American Buildings Survey Photographed by H.F. Withey April ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    6. Historic American Buildings Survey Photographed by H.F. Withey April 22nd, 1934. ARCADE TOWARD WEST - Mission San Fernando Rey de Espana, Monastery, San Fernando Mission Road, San Fernando, Los Angeles County, CA

  14. 3. Historic American Buildings Survey Photographed by H.F. Withey, April ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    3. Historic American Buildings Survey Photographed by H.F. Withey, April 22nd, 1934. MONASTERY NORTH ELEVATION. - Mission San Fernando Rey de Espana, Monastery, San Fernando Mission Road, San Fernando, Los Angeles County, CA

  15. 5. Historic American Buildings Survey Photographed by H.F. Withey April ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    5. Historic American Buildings Survey Photographed by H.F. Withey April 22nd, 1934. MONASTERY ARCADE FROM THE EAST FRONT - Mission San Fernando Rey de Espana, Monastery, San Fernando Mission Road, San Fernando, Los Angeles County, CA

  16. 1. Historic American Buildings Survey Photographed by H.F. Withey, April ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. Historic American Buildings Survey Photographed by H.F. Withey, April 22nd, 1934. MONASTERY SOUTH FRONT FROM SOUTH-WEST. - Mission San Fernando Rey de Espana, Monastery, San Fernando Mission Road, San Fernando, Los Angeles County, CA

  17. 2. Historic American Buildings Survey Photographed by H.F. Withey, April ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. Historic American Buildings Survey Photographed by H.F. Withey, April 22nd, 1934. MONASTERY SOUTH FRONT FROM SOUTH-EAST. - Mission San Fernando Rey de Espana, Monastery, San Fernando Mission Road, San Fernando, Los Angeles County, CA

  18. 2. Historic American Buildings Survey, Photographed by H.F. Withey, April ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. Historic American Buildings Survey, Photographed by H.F. Withey, April 22nd, 1934. CHURCH FROM THE SOUTH-WEST #2. - Mission San Fernando Rey de Espana, Church, Mission Road, San Fernando, Los Angeles County, CA

  19. 7. Historic American Buildings Survey, Photographed by H.F. Withey, April ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    7. Historic American Buildings Survey, Photographed by H.F. Withey, April 22nd, 1934. DOORWAY TO ROOM #4 IN ARCADE - Mission San Fernando Rey de Espana, Monastery, San Fernando Mission Road, San Fernando, Los Angeles County, CA

  20. Two-dimensional electron gas in GaAs/SrHfO3 heterostructure

    NASA Astrophysics Data System (ADS)

    Wang, Jianli; Yuan, Mengqi; Tang, Gang; Li, Huichao; Zhang, Junting; Guo, Sandong

    2016-06-01

    The III-V/perovskite-oxide system can potentially create new material properties and new device applications by combining the rich properties of perovskite-oxides together with the superior optical and electronic properties of III-Vs. The structural and electronic properties of the surface and interface are studied using first-principles calculations for the GaAs/SrHfO3 heterostructure. We investigate the specific adsorption sites and the atomic structure at the initial growth stage of GaAs on the SrHfO3 (001) substrate. Ga and As adsorption atoms preferentially adsorb at the top sites of oxygen atoms under different coverage. The energetically favorable interfaces are presented among the atomic arrangements of the GaAs/SrHfO3 interfaces. Our calculations predict the existing of the two-dimensional electron gas in the GaAs/SrHfO3 heterostructure.

  1. Oxidation of several corrosion-resistant metals in HF-DMF

    SciTech Connect

    Chulkevich, A.K.; Smolina, E.V.; Lavrent'ev, I.P.; Khidekel', M.L.

    1987-02-20

    The oxidative dissolution of transition metals in organic and aqueous organic media yields a broad range of complexes. In work, data are given on the dissolution of Ti, Zr, Nb, Ta, Cr, and Mn in HF-DMF and HF-DMF-H/sub 2/O/sub 2/ systems. The dimethylammonium oxyfluoride complexes were isolated and characterized. Metals of groups IV-VI may be oxidized in HF-DMF and HF-DMF-H/sub 2/O/sub 2/ systems. The dimethylammonium oxyfluoride complexes of titanium(IV), zirconium(IV), niobium(V), tantalum(V), and the oxyfluorides of chromium(III) and manganese(II) were isolated and characterized.

  2. Partition coefficients of Hf, Zr, and REE between zircon, apatite, and liquid

    USGS Publications Warehouse

    Fujimaki, H.

    1986-01-01

    Concentration ratios of Hf, Zr, and REE between zircon, apatite, and liquid were determined for three igneous compositions: two andesites and a diorite. The concentration ratios of these elements between zircon and corresponding liquid can approximate the partition coefficient. Although the concentration ratios between apatite and andesite groundmass can be considered as partition coefficients, those for the apatite in the diorite may deviate from the partition coefficients. The HREE partition coefficients between zircon and liquid are very large (100 for Er to 500 for Lu), and the Hf partition coefficient is even larger. The REE partition coefficients between apatite and liquid are convex upward, and large (D=10-100), whereas the Hf and Zr partition coefficients are less than 1. The large differences between partition coefficients of Lu and Hf for zircon-liquid and for apatite-liquid are confirmed. These partition coefficients are useful for petrogenetic models involving zircon and apatite. ?? 1986 Springer-Verlag.

  3. An error-resilient approach for real-time packet communications by HF-channel diversity

    NASA Astrophysics Data System (ADS)

    Navarro, Antonio; Rodrigues, Rui; Angeja, Joao; Tavares, Joao; Carvalho, Luis; Perdigao, Fernando

    2004-08-01

    This paper evaluates the performance of a high frequency (HF) wireless network for transporting packet multimedia services. Beyond of allowing civil/amateur communications, HF bands are also used for long distance wireless military communications. Therefore, our work is based on NATO Link and Physical layer standards, STANAG 5066 and STANAG 4539 respectively. At each HF channel, a typical transmission bandwidth is about 3 kHz with the resulting throughput bit rate up to 12800 bps. This very low bit rate by itself imposes serious challenges for reliable and low delay real time multimedia communications. Thus, this paper discusses the performance of a real time communication system designed to allow an end-to-end communication through "best effort" networks. With HF channel diversity, the packet loss percentage, on average considering three channel conditions, is decreased by 16% in the channel SNR range from 0 to 45 dB.

  4. Low albumin levels and high impedance ratio as risk factors for worsening kidney function during hospitalization of decompensated heart failure patients

    PubMed Central

    Valdespino-Trejo, Adrian; Orea-Tejeda, Arturo; Castillo-Martínez, Lilia; Keirns-Davis, Candace; Montañez-Orozco, Álvaro; Ortíz-Suárez, Gerson; Delgado-Pérez, D Alejandro; Marquez-Zepeda, Bianka

    2013-01-01

    BACKGROUND: Patients hospitalized for decompensated heart failure (DHF) frequently experience worsening of renal function (WRF), leading to volume overload and resistance to diuretics. OBJECTIVE: To investigate whether albumin levels and whole-body impedance ratio, as an indicator of water distribution, were associated with WRF in patients with DHF. Methods: A total of 80 patients hospitalized for DHF were consecutively included in the present longitudinal study. WRF during hospitalization was defined as an increase of ≥0.3 mg/dL (≥26.52 μmol/L) or 25% of baseline serum creatinine. Clinical and echocardiographic characteristics were assessed at baseline. Whole-body bioelectrical impedance was measured using tetrapolar and multiple-frequency equipment to obtain the ratio of impedance at 200 kHz to that at 5 kHz. Serum albumin levels were also evaluated. Baseline characteristics were compared between patients with and without deteriorating renal function using a t test or χ2 test. Subsequently, a logistic regression analysis was performed to obtain the independent variables associated with WRF. RESULTS: The incidence of WRF during hospitalization was 26%. Independent risk factors associated with WRF were low serum albumin (RR=0.11; P=0.04); impedance ratio >0.85 (RR=5.3; P=0.05), systolic blood pressure >160 mmHg (RR=12; P=0.02) and maximum dose of continuous intravenous furosemide required >80 mg/day during hospitalization (RR=5.7, P=0.015). CONCLUSIONS: WRF is frequent in patients with DHF. It results from the inability to effectively regulate volume status because hypoalbuminemia induces water loss from the vascular space (high impedance ratio), and high diuretic doses lower circulatory volumes and reduce renal blood flow, leading to a decline in renal filtration function. PMID:23940434

  5. Plasma etching of HfO{sub 2} at elevated temperatures in chlorine-based chemistry

    SciTech Connect

    Helot, M.; Chevolleau, T.; Vallier, L.; Joubert, O.; Blanquet, E.; Pisch, A.; Mangiagalli, P.; Lill, T.

    2006-01-15

    Plasma etching of HfO{sub 2} at an elevated temperature is investigated in chlorine-based plasmas. Thermodynamic studies are performed in order to determine the most appropriate plasma chemistry. The theoretical calculations show that chlorocarbon gas chemistries (such as CCl{sub 4} or Cl{sub 2}-CO) can result in the chemical etching of HfO{sub 2} in the 425-625 K temperature range by forming volatile effluents such as HfCl{sub 4} and CO{sub 2}. The etching of HfO{sub 2} is first studied on blanket wafers in a high density Cl{sub 2}-CO plasma under low ion energy bombardment conditions (no bias power). Etch rates are presented and discussed with respect to the plasma parameters. The evolution of the etch rate as function of temperature follows an Arrhenius law indicating that the etching comes from chemical reactions. The etch rate of HfO{sub 2} is about 110 A /min at a temperature of 525 K with a selectivity towards SiO{sub 2} of 15. x-ray photoelectron spectroscopy analyses (XPS) reveal that neither carbon nor chlorine is detected on the HfO{sub 2} surface, whereas a chlorine-rich carbon layer is formed on top of the SiO{sub 2} surface leading to the selectivity between HfO{sub 2} and SiO{sub 2}. A drift of the HfO{sub 2} etch process is observed according to the chamber walls conditioning due to chlorine-rich carbon coatings formed on the chamber walls in a Cl{sub 2}-CO plasma. To get a very reproducible HfO{sub 2} etch process, the best conditioning strategy consists in cleaning the chamber walls with an O{sub 2} plasma between each wafer. The etching of HfO{sub 2} is also performed on patterned wafers using a conventional polysilicon gate. The first result show a slight HfO{sub 2} foot at the bottom of the gate and the presence of hafnium oxide-based residues in the active areas.

  6. Subduction Controls of Hf and Nd Isotopes in Lavas of the Aleutian Island Arc

    SciTech Connect

    Yogodzinski, Gene; Vervoort, Jeffery; Brown, Shaun Tyler; Gerseny, Megan

    2010-08-29

    The Hf and Nd isotopic compositions of 71 Quaternary lavas collected from locations along the full length of the Aleutian island arc are used to constrain the sources of Aleutian magmas and to provide insight into the geochemical behavior of Nd and Hf and related elements in the Aleutian subduction-magmatic system. Isotopic compositions of Aleutian lavas fall approximately at the center of, and form a trend parallel to, the terrestrial Hf-Nd isotopic array with {var_epsilon}{sub Hf} of +12.0 to +15.5 and {var_epsilon}{sub Nd} of +6.5 to +10.5. Basalts, andesites, and dacites within volcanic centers or in nearby volcanoes generally all have similar isotopic compositions, indicating that there is little measurable effect of crustal or other lithospheric assimilation within the volcanic plumbing systems of Aleutian volcanoes. Hafnium isotopic compositions have a clear pattern of along-arc increase that is continuous from the eastern-most locations near Cold Bay to Piip Seamount in the western-most part of the arc. This pattern is interpreted to reflect a westward decrease in the subducted sediment component present in Aleutian lavas, reflecting progressively lower rates of subduction westward as well as decreasing availability of trench sediment. Binary bulk mixing models (sediment + peridotite) demonstrate that 1-2% of the Hf in Aleutian lavas is derived from subducted sediment, indicating that Hf is mobilized out of the subducted sediment with an efficiency that is similar to that of Sr, Pb and Nd. Low published solubility for Hf and Nd in aqueous subduction fluids lead us to conclude that these elements are mobilized out of the subducted component and transferred to the mantle wedge as bulk sediment or as a silicate melt. Neodymium isotopes also generally increase from east to west, but the pattern is absent in the eastern third of the arc, where the sediment flux is high and increases from east to west, due to the presence of abundant terrigenous sediment in the

  7. Exposure to Discrimination and Heart Rate Variability Reactivity to Acute Stress among Women with Diabetes.

    PubMed

    Wagner, Julie; Lampert, Rachel; Tennen, Howard; Feinn, Richard

    2015-08-01

    Exposure to racial discrimination has been linked to physiological reactivity. This study investigated self-reported exposure to racial discrimination and parasympathetic [high-frequency heart rate variability (HF-HRV)] and sympathetic (norepinephrine and cortisol) activity at baseline and then again after acute laboratory stress. Lifetime exposure to racial discrimination was measured with the Schedule of Racist Events scale. Thirty-two women (16 Black and 16 White) with type 2 diabetes performed a public speaking stressor. Beat-to-beat intervals were recorded on electrocardiograph recorders, and HF-HRV was calculated using spectral analysis and natural log transformed. Norepinephrine and cortisol were measured in blood. Higher discrimination predicted lower stressor HF-HRV, even after controlling for baseline HF-HRV. When race, age, A1c and baseline systolic blood pressure were also controlled, racial discrimination remained a significant independent predictor of stressor HF-HRV. There was no association between lifetime discrimination and sympathetic markers. In conclusion, preliminary data suggest that among women with type 2 diabetes mellitus (T2DM), exposure to racial discrimination is adversely associated with parasympathetic, but not sympathetic, reactivity.

  8. Evolution of magnetic properties and microstructure of Hf2Co11B alloys

    SciTech Connect

    McGuire, Michael A.; Rios, Orlando

    2015-02-05

    Amorphous Hf2Co11B alloys produced by melt-spinning have been crystallized by annealing at 500-800 °C, and the products have been investigated using magnetization measurements, x-ray diffraction, and scanning electron microscopy. The results reveal the evolution of the phase fractions, microstructure, and magnetic properties with both annealing temperature and time. Crystallization of the phase denoted HfCo7, which is associated with the development of coercivity, occurs slowly at 500 °C. Annealing at intermediate temperatures produces mixed phase samples containing some of the HfCo7 phase with the highest values of remanent magnetization and coercivity. The equilibrium structure at 800 °C contains HfCo3B2, Hf6Co23 and Co, and displays soft ferromagnetism. Maximum values for the remanent magnetization, intrinsic coercivity, and magnetic energy product among the samples are approximately 5.2 kG, 2.0 kOe, and 3.1 MGOe, respectively, which indicates that the significantly higher values observed in crystalline, melt-spun Hf2Co11B ribbons are a consequence of the non-equilibrium solidification during the melt-spinning process. Application of high magnetic fields during annealing is observed to strongly affect the microstructural evolution, which may provide access to higher performance materials in Zr/Hf-Co hard ferromagnets. The crystal structure of HfCo7 and the related Zr analogues is unknown, and without knowledge of atomic positions powder diffraction cannot distinguish among proposed unit cells and symmetries found in the literature.

  9. Evolution of magnetic properties and microstructure of Hf2Co11B alloys

    DOE PAGES

    McGuire, Michael A.; Rios, Orlando

    2015-02-05

    Amorphous Hf2Co11B alloys produced by melt-spinning have been crystallized by annealing at 500-800 °C, and the products have been investigated using magnetization measurements, x-ray diffraction, and scanning electron microscopy. The results reveal the evolution of the phase fractions, microstructure, and magnetic properties with both annealing temperature and time. Crystallization of the phase denoted HfCo7, which is associated with the development of coercivity, occurs slowly at 500 °C. Annealing at intermediate temperatures produces mixed phase samples containing some of the HfCo7 phase with the highest values of remanent magnetization and coercivity. The equilibrium structure at 800 °C contains HfCo3B2, Hf6Co23 andmore » Co, and displays soft ferromagnetism. Maximum values for the remanent magnetization, intrinsic coercivity, and magnetic energy product among the samples are approximately 5.2 kG, 2.0 kOe, and 3.1 MGOe, respectively, which indicates that the significantly higher values observed in crystalline, melt-spun Hf2Co11B ribbons are a consequence of the non-equilibrium solidification during the melt-spinning process. Application of high magnetic fields during annealing is observed to strongly affect the microstructural evolution, which may provide access to higher performance materials in Zr/Hf-Co hard ferromagnets. The crystal structure of HfCo7 and the related Zr analogues is unknown, and without knowledge of atomic positions powder diffraction cannot distinguish among proposed unit cells and symmetries found in the literature.« less

  10. Nickel nanocrystal formation on HfO2 dielectric for nonvolatile memory device applications

    NASA Astrophysics Data System (ADS)

    Lee, Jong Jin; Harada, Yoshinao; Pyun, Jung Woo; Kwong, Dim-Lee

    2005-03-01

    This letter presents the formation of nickel nanocrystal on HfO2 high-k dielectric and its application to the nonvolatile memory devices. The effects of the initial nickel layer thickness and annealing temperature on nickel nanocrystal formation are investigated. The n-metal-oxide-semiconductor field-effect transistor with nickel nanocrystals and HfO2 tunneling dielectrics is fabricated and its programming, data retention, and endurance properties are characterized to demonstrate its advantages for nonvolatile memory device applications.

  11. Slow strain rate 1200-1400 K compressive properties of NiAl-1Hf

    NASA Technical Reports Server (NTRS)

    Whittenberger, J. D.; Nathal, M. V.; Raj, S. V.; Pathare, V. M.

    1991-01-01

    Compression tests are conducted on NiAl-1Hf to assess the elevated-temperature creep behavior of this precipitation-hardened aluminide. While the strength is high under fast strain rates (more than 10 exp -5/s), under slower conditions the alloy is weak. Thus, it is unlikely that effective creep resistance can be obtained in NiAl through small Hf additions.

  12. Evolution of magnetic properties and microstructure of Hf2Co11B alloys

    NASA Astrophysics Data System (ADS)

    McGuire, Michael A.; Rios, Orlando

    2015-02-01

    Amorphous Hf2Co11B alloys produced by melt-spinning have been crystallized by annealing at 500-800 °C, and the products have been investigated using magnetization measurements, x-ray diffraction, and scanning electron microscopy. The results reveal the evolution of the phase fractions, microstructure, and magnetic properties with both annealing temperature and time. Crystallization of the phase denoted HfCo7, which is associated with the development of coercivity, occurs slowly at 500 °C. Annealing at intermediate temperatures produces mixed phase samples containing some of the HfCo7 phase with the highest values of remanent magnetization and coercivity. The equilibrium structure at 800 °C contains HfCo3B2, Hf6Co23, and Co, and displays soft ferromagnetism. Maximum values for the remanent magnetization, intrinsic coercivity, and magnetic energy product among the samples are approximately 5.2 kG, 2.0 kOe, and 3.1 MGOe, respectively, which indicates that the significantly higher values observed in crystalline, melt-spun Hf2Co11B ribbons are a consequence of the non-equilibrium solidification during the melt-spinning process. Application of high magnetic fields during annealing is observed to strongly affect the microstructural evolution, which may provide access to higher performance materials in Zr/Hf-Co hard ferromagnets. The crystal structure of HfCo7 and the related Zr analogues is unknown, and without knowledge of atomic positions powder diffraction cannot distinguish among proposed unit cells and symmetries found in the literature.

  13. Coherent HF Radar System for the Study of Natural and Heater Induced Ionospheric Irregularities

    DTIC Science & Technology

    1993-06-01

    Services HF Active Auroral Research Program ( HAARP ) in Alaska. The DPS characterizes the bulk parameters of the ionosphere including changes of the...electron density, plasma structure and the plasma convection. In the absence of the HAARP facility at the present time, the high latitude ionosphere at...AD-A273 804 COHERENT HF RADAR SYSTEM FOR THE STUDY OF NATURAL AND HEATER INDUCED IONOSPHERIC IRREGULARITIES Bodo W. Reinisch James L. Scali D. Mark

  14. Infrared spectroscopy of the bent isomer of N 2O-HF

    NASA Astrophysics Data System (ADS)

    Dayton, D. C.; Miller, R. E.

    1988-02-01

    We report the infrared spectrum of the bent isomer of N 2O-HF in which the HF subnit is hydrogen bonded to the oxygen. This isomer was previously observed using microwave spectroscopy, while recent infrared measurements by Lovejoy and Nesbitt have shown that a linear (or slightly bent) ONNHF isomer also exists. We find that the linear ONNHF isomer is present under identical beam conditions to those used to record the spectrum of the bent isomer.

  15. Power-Stepped HF Cross-Modulation Experiments: Simulations and Experimental Observations

    NASA Astrophysics Data System (ADS)

    Greene, S.; Moore, R. C.

    2014-12-01

    High frequency (HF) cross modulation experiments are a well established means for probing the HF-modified characteristics of the D-region ionosphere. The interaction between the heating wave and the probing pulse depends on the ambient and modified conditions of the D-region ionosphere. Cross-modulation observations are employed as a measure of the HF-modified refractive index. We employ an optimized version of Fejer's method that we developed during previous experiments. Experiments were performed in March 2013 at the High Frequency Active Auroral Research Program (HAARP) observatory in Gakona, Alaska. During these experiments, the power of the HF heating signal incrementally increased in order to determine the dependence of cross-modulation on HF power. We found that a simple power law relationship does not hold at high power levels, similar to previous ELF/VLF wave generation experiments. In this paper, we critically compare these experimental observations with the predictions of a numerical ionospheric HF heating model and demonstrate close agreement.

  16. DEMETER observations of the ionospheric trough over HAARP in relation to HF heating experiments

    NASA Astrophysics Data System (ADS)

    Piddyachiy, D.; Bell, T. F.; Berthelier, J.-J.; Inan, U. S.; Parrot, M.

    2011-06-01

    Plasma density variations observed aboard the DEMETER satellite in the topside ionospheric F layer are analyzed in relation to high-frequency transmitter operations. The main interest is the high-latitude region. One hundred cases with operating and nonoperating High Frequency Active Auroral Research Program HF transmitter during day and night are examined. It is found that most large-scale variations can be attributed to the presence of the main ionospheric trough and that such natural variations complicate the detection of HF transmitter effects on a case-by-case basis. From statistics, no correlation between the HF transmissions and the presence of the irregularities has been established. A comparison of our observations with two recent works on electron density ducts created by HF transmitters and detected by DEMETER shows that in those works the main ionospheric trough is the major factor in density variations, and it is not clear how to distinguish density variations created by the HF heater from natural variations in such cases. Finally, possible experimental techniques for duct formation by HF heaters are discussed.

  17. Anomalously large band-bending for HF-treated p-Si surfaces

    NASA Astrophysics Data System (ADS)

    Watanabe, D.; En, A.; Nakamura, S.; Suhara, M.; Okumura, T.

    2003-06-01

    Electronic properties of the HF-treated Si surfaces have been characterized by the Kelvin method combined with surface photovoltage (SPV) measurements. With the use of 340 nm ultraviolet light source, a relatively large SPV of -0.45 V was detected at a photocurrent density of 1 mA/cm 2 for the diluted (e.g. 4.5%) HF-treated p-Si(0 0 1) surface. On the other hand, no SPV was induced for the HF-treated n-Si(0 0 1) wafer. This result indicates that there is anomalously large surface band-bending toward the surface, and Fermi-level position at the surface is pinned in the vicinity of the bottom of the conduction band at the HF-treated p-Si(1 0 0). It is considered that the residual fluorine responsible for an anomalously large band-bending at the p-Si(1 0 0) surface treated with HF. Furthermore, the value of the built-in potential for the HF-treated p-Si(0 0 1) surface was estimated to be about 0.60 eV at the room temperature from the result of the temperature dependence of the effective saturation current.

  18. Hf, Zr, and REE partition coefficients between ilmenite and liquid - Implications for lunar petrogenesis

    NASA Technical Reports Server (NTRS)

    Nakamura, Y.; Fujimaki, H.; Nakamura, N.; Tatsumoto, M.; Mckay, G. A.

    1986-01-01

    Partition coefficients (D) between ilmenite and coexisting liquid were determined under near-lunar conditions for Hf, Zr, and REE. Through isotope dilution analysis, ilmenite D values of 0.41 and 0.33 were obtained for Hf and Zr respectively, values significantly lower than those of ilmenite from a kimberlite megacryst. Partition coefficients of REE for the synthesized ilmenite are slightly smaller than those of ilmenite from the kimberlite megacryst, and the lunar (Lu) partition coefficient is 0.056. These results suggest that ilmenite was significant in the lunar-Hf evolution of lunar mare basalts. Using lunar and Hf D values for ilmenite, the Lu-Hf evolution of lunar cumulates and the coexisting magma was examined for various crystallization sequences. The Lu-Hf variation trend of most high-Ti mare basalts is explained by a small degree of partial cumulate melting, though a higher degree is required to explain the variation of very low-Ti basalts, green glass, and Apollo 12 low-Ti basalts. Apollo 15 low-Ti basalts may require chromite crystallization as well.

  19. Partition coefficients of Hf, Zr, and REE between phenocrysts and groundmasses

    NASA Technical Reports Server (NTRS)

    Fujimaki, H.; Tatsumoto, M.; Aoki, K.-I.

    1984-01-01

    Partition coefficients of Hf, Zr, and REE between olivine, orthopyroxene, clinopyroxene, plagioclase, garnet, amphibole, ilmenite, phlogopite, and liquid are presented. Samples consist of megacrysts in kimberlite, phenocrysts in alkaline basalts, tholeiitic basalts and andesitic to dacitic rocks, and synthetic garnet and clinopyroxene in Hawaiian tholeiites. The Hf-Lu and Zr-Lu elemental fractionations are as large as the Lu-Sm or Lu-Nd fractionation. The Hf and Zr partition coefficients between mafic phenocrysts and liquids are smaller than the Lu partition coefficients, but are similar to the Nd or Sm partition coefficients. The Hf and Zr partition coefficients between ilmenite, phlogopite, and liquid are larger than the Lu partition coefficients for these minerals and their corresponding liquids. The Hf-Zr elemental fractionation does not occur except for extreme fractionation involving Zr-minerals and extremely low fO2. These data have an important bearing on chronological and petrogenetic tracer studies involving the Lu-Hf isotopic system.

  20. ELF/VLF wave generation from the beating of two HF ionospheric heating sources

    NASA Astrophysics Data System (ADS)

    Cohen, M. B.; Moore, R. C.; Golkowski, M.; Lehtinen, N. G.

    2012-12-01

    It is well established that Extremely Low Frequency (ELF, 0.3-3 kHz) and Very Low Frequency (VLF, 3-30 kHz) radio waves can be generated via modulated High Frequency (HF, 3-10 MHz) heating of the lower ionosphere (60-100 km). The ionospheric absorption of HF power modifies the conductivity of the lower ionosphere, which in the presence of natural currents such as the auroral electrojet, creates an `antenna in the sky.' We utilize a theoretical model of the HF to ELF/VLF conversion and the ELF/VLF propagation, and calculate the amplitudes of the generated ELF/VLF waves when two HF heating waves, separated by the ELF/VLF frequency, are transmitted from two adjacent locations. The resulting ELF/VLF radiation pattern exhibits a strong directional dependence (as much as 15 dB) that depends on the physical spacing of the two HF sources. This beat wave source can produce signals 10-20 dB stronger than those generated using amplitude modulation, particularly for frequencies greater than 5-10 kHz. We evaluate recent suggestions that beating two HF waves generates ELF/VLF waves in the F-region (>150 km), and conclude that those experimental results may have misinterpreted, and can be explained strictly by the much more well established D region mechanism.