Science.gov

Sample records for acute decompensated hf

  1. Cardiac Rhythm Monitoring After Acute Decompensation for Heart Failure: Results from the CARRYING ON for HF Pilot Study

    PubMed Central

    Mortara, Andrea; Diotallevi, Paolo; Gallone, Giuseppe; Mariconti, Barbara; Gronda, Edoardo; Gentili, Alessandra; Bisetti, Silvia; Botto, Giovanni Luca

    2016-01-01

    Background There’s scarce evidence about cardiovascular events (CV) in patients with hospitalization for acute heart failure (HF) and no indication for immediate device implant. Objective The CARdiac RhYthm monitorING after acute decompensatiON for Heart Failure study was designed to assess the incidence of prespecified clinical and arrhythmic events in this patient population. Methods In this pilot study, 18 patients (12 (67%) male; age 72±10; 16 (89%) NYHA II-III), who were hospitalized for HF with low left ventricular ejection fraction (LVEF) (<40%) and no immediate indication for device implant received an implantable loop recorder (ILR) before hospital discharge. Follow-up visits were scheduled at 3 and 6 months, and at every 6 months until study closure; device data were remotely reviewed monthly. CV mortality, unplanned CV hospitalization, and major arrhythmic events during follow-up were analyzed. Results During a median follow-up of 593 days, major CV occurred in 13 patients (72%); of those, 7 patients had at least 1 cardiac arrhythmic event, 2 had at least a clinical event (CV hospitalization or CV death), and 4 had both an arrhythmic and a CV event. Six (33%) patients experienced 10 major clinical events, 5 of them (50%) were HF related. During follow-up, 2 (11%) patients died due to a CV cause and 3 (16%) patients received a permanent cardiac device. Conclusions After an acute HF hospitalization, patients with LVEF<40% and who are not readily eligible for permanent cardiac device implant have a known high incidence of major CV event. In these patients, ILR allows early detection of major cardiac arrhythmias and the ability to react appropriately in a timely manner. Trial Registration ClinicalTrials.gov NCT01216670; https://clinicaltrials.gov/ct2/show/NCT01216670 PMID:27118481

  2. 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

  3. Acute Decompensated Heart Failure Update

    PubMed Central

    Teerlink, John R; Alburikan, Khalid; Metra, Marco; Rodgers, Jo E

    2015-01-01

    Acute decompensated heart failure (ADHF) continues to increase in prevalence and is associated with substantial mortality and morbidity including frequent hospitalizations. The American Heart Association is predicting that more than eight million Americans will have heart failure by 2030 and that the total direct costs associated with the disease will rise from $21 billion in 2012 to $70 billion in 2030. The increase in the prevalence and cost of HF is primarily the result of shifting demographics and a growing population. Although many large, randomized, controlled clinical trials have been conducted in patients with chronic heart failure, it was not until recently that a growing number of studies began to address the management of ADHF. It is the intent of this review to update the clinician regarding the evaluation and optimal management of ADHF. PMID:24251454

  4. Management of acute decompensated heart failure.

    PubMed

    Varughese, Sheeba

    2007-01-01

    Heart failure, a debilitating complex clinical syndrome, affects nearly 5 million people in the United States and presents a heavy socioeconomic burden. Neurohormonal abnormalities contribute to the pathophysiology of heart failure. Acute decompensated heart failure (ADHF) has emerged as a major health problem associated with poor prognosis, increased costs related to care, reduced quality of life, and frequent readmissions. Symptoms of ADHF are primarily related to congestion and/or low perfusion states. The use of biomakers such as B-natriuretic peptides is useful in distinguishing between cardiac and noncardiac causes of symptoms. Treatment for ADHF begins with identification and treatment of precipitating factors for acute decompensation. Initial goal of therapy is focused on symptom management followed by interventions that delay disease progression, reduce readmission, and prolong survival. PMID:17356351

  5. Evaluating the Safety and Efficacy of Sodium-Restricted/Dietary Approaches to Stop Hypertension Diet After Acute Decompensated Heart Failure Hospitalization: Design and Rationale for the Geriatric OUt of hospital Randomized MEal Trial in Heart Failure (GOURMET-HF)

    PubMed Central

    Wessler, Jeffrey D.; Maurer, Mathew S.; Hummel, Scott S.

    2015-01-01

    Background Heart Failure (HF) is a major public health problem affecting predominantly older adults. Non-adherence to diet remains a significant contributor to acute decompensated HF (ADHF). The sodium-restricted Dietary Approaches to Stop Hypertension (DASH/SRD) eating plan reduces cardiovascular dysfunction that can lead to ADHF and is consistent with current HF guidelines. We propose that an intervention that promotes adherence to the DASH/SRD by home-delivering meals will be safe and improve health-related quality of life (QOL) in older adults following hospitalization for ADHF. Methods/Design This is a three center, randomized, single-blind, controlled trial of 12 weeks duration designed to determine the safety and efficacy of home-delivered DASH/SRD-compliant meals in older adults following discharge from ADHF hospitalization. 66 subjects will be randomized in a 1:1 stratified fashion by gender and left ventricular ejection fraction (< vs. ≥50%). Study subjects will receive either pre-prepared, home-delivered DASH/SRD-compliant meals or usual dietary advice for 4 weeks after hospital discharge. Investigators will be blinded to group assignment, food diaries, and urinary electrolyte measurements until study completion. The primary efficacy endpoint is the change in the Kansas City Cardiomyopathy Questionnaire (KCCQ) summary scores for health-related QOL from study enrollment to 4 weeks post-discharge. Safety evaluation will focus on hypotension, renal insufficiency, and hyperkalemia. Exploratory endpoints include echocardiography, non-invasive vascular testing, markers of oxidative stress, and salt taste sensitivity. Conclusion This randomized controlled trial will test the efficacy, feasibility and safety of 4 weeks of DASH/SRD after ADHF hospitalization. By testing a novel dietary intervention supported by multiple levels of evidence including preliminary data in outpatients with stable HF, we will address a critical evidence gap in the care of older

  6. Detecting Heart Failure Decompensation by Measuring Transthoracic Bioimpedance in the Outpatient Setting: Rationale and Design of the SENTINEL-HF Study

    PubMed Central

    Saczynski, Jane S; Darling, Chad E; Riistama, Jarno; Sert Kuniyoshi, Fatima; Meyer, Theo; Goldberg, Robert; McManus, David D

    2015-01-01

    Background Recurrent hospital admissions are common among patients admitted for acute decompensated heart failure (ADHF), but identification of patients at risk for rehospitalization remains challenging. Contemporary heart failure (HF) management programs have shown modest ability to reduce readmissions, partly because they monitor signs or symptoms of HF worsening that appear late during decompensation. Detecting early stages of HF decompensation might allow for immediate application of effective HF therapies, thereby potentially reducing HF readmissions. One of the earliest indicators of HF decompensation is intrathoracic fluid accumulation, which can be assessed using transthoracic bioimpedance. Objective The SENTINEL-HF study is a prospective observational study designed to test a novel, wearable HF monitoring system as a predictor of HF decompensation among patients discharged after hospitalization for ADHF. Methods SENTINEL-HF tests the hypothesis that a decline in transthoracic bioimpedance, as assessed daily with the Philips fluid accumulation vest (FAV) and transmitted using a mobile phone, is associated with HF worsening and rehospitalization. According to pre-specified power calculations, 180 patients admitted with ADHF are enrolled. Participants transmit daily self-assessments using the FAV-mobile phone dyad for 45 days post-discharge. The primary predictor is the deviation of transthoracic bioimpedance for 3 consecutive days from a patient-specific normal variability range. The ADHF detection algorithm is evaluated in relation with a composite outcome of HF readmission, diuretic up-titration, and self-reported HF worsening (Kansas City Cardiomyopathy Questionnaire) during a 90-day follow-up period. Here, we provide the details and rationale of SENTINEL-HF. Results Enrollment in the SENTINEL-HF study is complete and the 90-days follow-up is currently under way. Once data collection is complete, the study dataset will be used to evaluate our ADHF

  7. 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

  8. Therapeutic Potential of Nitroxyl (HNO) Donors in the Management of Acute Decompensated Heart Failure.

    PubMed

    Kemp-Harper, Barbara K; Horowitz, John D; Ritchie, Rebecca H

    2016-09-01

    Heart failure (HF) is a major cause of hospital admission in the Western world, yet there remains a paucity of effective pharmacological management options. With the recent development of synthetic, next-generation nitroxyl (HNO) donors and their progress into clinical trials, it is timely to now provide an update on the therapeutic potential of HNO donors in the management of acute decompensated heart failure. In this article, we summarize current understanding of the pharmacology of HNO (in comparison with its redox sibling, nitric oxide), its spectrum of cardioprotective actions, and efforts to translate these into the clinic. Future research directions for this exciting new class of HF drugs are also considered. PMID:27566478

  9. Lung Ultrasound in the Management of Acute Decompensated Heart Failure

    PubMed Central

    Ang, Shiang-Hu; Andrus, Phillip

    2012-01-01

    Once thought impracticable, lung ultrasound is now used in patients with a variety of pulmonary processes. This review seeks to describe the utility of lung ultrasound in the management of patients with acute decompensated heart failure (ADHF). A literature search was carried out on PubMed/Medline using search terms related to the topic. Over three thousand results were narrowed down via title and/or abstract review. Related articles were downloaded for full review. Case reports, letters, reviews and editorials were excluded. Lung ultrasonographic multiple B-lines are a good indicator of alveolar interstitial syndrome but are not specific for ADHF. The absence of multiple B-lines can be used to rule out ADHF as a causative etiology. In clinical scenarios where the assessment of acute dyspnea boils down to single or dichotomous pathologies, lung ultrasound can help rule in ADHF. For patients being treated for ADHF, lung ultrasound can also be used to monitor response to therapy. Lung ultrasound is an important adjunct in the management of patients with acute dyspnea or ADHF. PMID:22708913

  10. Venous Congestion, Endothelial and Neurohormonal Activation in Acute Decompensated Heart Failure: Cause or Effect?

    PubMed Central

    Colombo, Paolo C.; Doran, Amanda C.; Onat, Duygu; Wong, Ka Yuk; Ahmad, Myra; Sabbah, Hani N.; Demmer, Ryan T.

    2015-01-01

    Venous congestion and endothelial and neurohormonal activation are known to occur in acute decompensated heart failure (ADHF), yet the temporal role of these processes in the pathophysiology of decompensation is not fully understood. Conventional wisdom presumes congestion to be a consequence of worsening cardiovascular function; however, the biomechanically driven effects of venous congestion are biologically plausible contributors to ADHF that remain largely unexplored in vivo. Recent experimental evidence from human models suggests that fluid accumulation and venous congestion are not simply consequences of poor cardiovascular function, but rather are fundamental pro-oxidant, pro-inflammatory, and hemodynamic stimuli that contribute to acute decompensation. The latest advances in the monitoring of volume status using implantable devices allow for the detection of venous congestion before symptoms arise. This may ultimately lead to improved treatment strategies including not only diuretics, but also specific, adjuvant interventions to counteract endothelial and neurohormonal activation during early preclinical decompensation. PMID:25740404

  11. 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.

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

    PubMed Central

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

    2014-01-01

    ABSTRACT 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

  13. Triple Diuretics and Aquaretic Strategy for Acute Decompensated Heart Failure due to Volume Overload

    PubMed Central

    Estrada, Chelsea; Patel, Sagar; Weisfelner Bloom, Michelle; Wadhwa, Nand K.

    2013-01-01

    Diuretics, including furosemide, metolazone, and spironolactone, have historically been the mainstay of therapy for acute decompensated heart failure patients. The addition of an aquaretic-like vasopressin antagonist may enhance diuresis further. However, clinical experience with this quadruple combination is lacking in the acute setting. We present two hospitalized patients with acute decompensated heart failure due to massive fluid overload treated with a combination strategy of triple diuretics in conjunction with the aquaretic tolvaptan. The first patient lost 72.1 lbs. (32.7 kg) with an average urine output of 3.5 to 7.5 L/day over eight days on combined therapy with furosemide, metolazone, spironolactone, and tolvaptan. The second patient similarly achieved a weight loss of 28.2 lbs. (12.8 kg) over 4 days on the same treatment. Both patients maintained stable serum sodium, potassium, and creatinine over this period and remained out of the hospital for more than 30 days. Thus, patients hospitalized with acute decompensated heart failure due to volume overload can achieve euvolemia rapidly and without electrolytes disturbances using this regimen, while being under the close supervision of a team of cardiologists and nephrologists. Additionally, this therapy can potentially decrease the need for ultrafiltration and the length of hospital stay. PMID:24829808

  14. [Piretanide in chronic and acute decompensated heart failure. Effect on hemodynamics and vasoactive hormones].

    PubMed

    Sievert, H; Hopf, R; Vens-Cappell, F; Kirsten, R; Nelson, K; Pooth, R; Kaltenbach, M

    1989-06-15

    Eight patients with chronic heart failure classified as NYHA class II to III (group 1) and nine patients with acute decompensated heart failure classified as NYHA class IV (group 2) were treated with piretanide at a dosage of 12 mg administered intravenously. In both groups the level of prostaglandine PGE2 as well as plasma renine activity significantly increased prior to the onset of diuresis. The percentage increase was more pronounced in group 1 which had lower baseline values. With a time-lag, the norepinephrine plasma level also increased significantly. During the first 30 minutes there was only little effect on blood pressure, pulmonary artery pressure and cardiac output in patients with chronic heart failure (group 1). Only after 60 minutes there was a significant decrease in mean pulmonary artery pressure (from 39 +/- 17 to 33 +/- 18 mm Hg; p less than 0.05). In patients with acute decompensated heart failure (group 2) piretanide led to a significant reduction in mean pulmonary artery pressure (from 42 +/- 13 to 37 +/- 12 mm Hg; p less than 0.05) within 15 minutes after administration, i.e. even prior to the onset of diuresis. Thus, the administration of piretanide had a positive effect on hemodynamics in patients with chronic as well as in patients with acute decompensated heart failure. Significant improvement prior to diuresis onset, however, was only found in patients with acute decompensated heart failure. These effects may be explained by a stimulation of prostaglandines which promote vasodilation. They are increased by the diuresis.(ABSTRACT TRUNCATED AT 250 WORDS)

  15. Haemodialysis is an effective treatment in acute metabolic decompensation of maple syrup urine disease

    PubMed Central

    Atwal, P.S.; Macmurdo, C.; Grimm, P.C.

    2015-01-01

    Acute metabolic decompensation in maple syrup urine disease can occur during intercurrent illness and is a medical emergency. A handful of reports in the medical literature describe the use of peritoneal dialysis and haemodialysis as therapeutic inventions. We report the only patient from our centre to have haemodialysis performed in this setting. Combined with dietary BCAA restriction and calorific support, haemodialysis allows rapid reduction in plasma leucine concentrations considerably faster than conservative methods. PMID:26937409

  16. Haemodialysis is an effective treatment in acute metabolic decompensation of maple syrup urine disease.

    PubMed

    Atwal, P S; Macmurdo, C; Grimm, P C

    2015-09-01

    Acute metabolic decompensation in maple syrup urine disease can occur during intercurrent illness and is a medical emergency. A handful of reports in the medical literature describe the use of peritoneal dialysis and haemodialysis as therapeutic inventions. We report the only patient from our centre to have haemodialysis performed in this setting. Combined with dietary BCAA restriction and calorific support, haemodialysis allows rapid reduction in plasma leucine concentrations considerably faster than conservative methods. PMID:26937409

  17. Incidence and survival of hospitalized acute decompensated heart failure in four US communities (from the Atherosclerosis Risk in Communities Study).

    PubMed

    Chang, Patricia P; Chambless, Lloyd E; Shahar, Eyal; Bertoni, Alain G; Russell, Stuart D; Ni, Hanyu; He, Max; Mosley, Thomas H; Wagenknecht, Lynne E; Samdarshi, Tandaw E; Wruck, Lisa M; Rosamond, Wayne D

    2014-02-01

    Most population-based estimates of incident hospitalized heart failure (HF) have not differentiated acute decompensated heart failure (ADHF) from chronic stable HF nor included racially diverse populations. The Atherosclerosis Risk in Communities Study conducted surveillance of hospitalized HF events (age ≥55 years) in 4 US communities. We estimated hospitalized ADHF incidence and survival by race and gender. Potential 2005 to 2009 HF hospitalizations were identified by International Classification of Diseases, Ninth Revision, Clinical Modification, codes; 6,168 records were reviewed to validate ADHF cases. Population estimates were derived from US Census data; 50% of eligible hospitalizations were classified as ADHF, of which 63.6% were incident ADHF and 36.4% were recurrent ADHF. The average incidence of hospitalized ADHF was 11.6 per 1,000 persons, aged ≥55 years, per year, and recurrent hospitalized ADHF was 6.6 per 1,000 persons/yr. Age-adjusted annual ADHF incidence was highest for black men (15.7 per 1,000), followed by black women (13.3 per 1,000), white men (12.3 per 1,000), and white women (9.9 per 1,000). Of incident ADHF events with heart function assessment (89%), 53% had reduced the ejection fraction (heart failure with reduced ejection fraction [HFrEF]) and 47% had preserved ejection fraction (heart failure with preserved ejection fraction [HFpEF]). Black men had the highest proportion of acute HFrEF events (70%); white women had the highest proportion of acute HFpEF (59%). Age-adjusted 28-day and 1-year case fatality after an incident ADHF was 10.4% and 29.5%, respectively. Survival did not differ by race or gender. In conclusion, ADHF hospitalization and HF type varied by both race and gender, but case fatality rates did not. Further studies are needed to explain why black men are at higher risk of hospitalized ADHF and HFrEF.

  18. Hepatic encephalopathy in patients with acute decompensation of cirrhosis and acute-on-chronic liver failure.

    PubMed

    Romero-Gómez, Manuel; Montagnese, Sara; Jalan, Rajiv

    2015-02-01

    Hepatic encephalopathy in a hospitalized cirrhotic patient is associated with a high mortality rate and its presence adds further to the mortality of patients with acute-on-chronic liver failure (ACLF). The exact pathophysiological mechanisms of HE in this group of patients are unclear but hyperammonemia, systemic inflammation (including sepsis, bacterial translocation, and insulin resistance) and oxidative stress, modulated by glutaminase gene alteration, remain as key factors. Moreover, alcohol misuse, hyponatremia, renal insufficiency, and microbiota are actively explored. HE diagnosis requires exclusion of other causes of neurological, metabolic and psychiatric dysfunction. Hospitalization in the ICU should be considered in every patient with overt HE, but particularly if this is associated with ACLF. Precipitating factors should be identified and treated as required. Evidence-based specific management options are limited to bowel cleansing and non-absorbable antibiotics. Ammonia lowering drugs, such as glycerol phenylbutyrate and ornithine phenylacetate show promise but are still in clinical trials. Albumin dialysis may be useful in refractory cases. Antibiotics, prebiotics, and treatment of diabetes reduce systemic inflammation. Where possible and not contraindicated, large portal-systemic shunts may be embolized but liver transplantation is the most definitive step in the management of HE in this setting. HE in patients with ACLF appears to be clinically and pathophysiologically distinct from that of acute decompensation and requires further studies and characterization.

  19. 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.

  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. 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.

  2. 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.

  3. Geographic Differences in Patients in a Global Acute Heart Failure Clinical Trial (from the ASCEND-HF Trial).

    PubMed

    Metra, Marco; Mentz, Robert J; Hernandez, Adrian F; Heizer, Gretchen M; Armstrong, Paul W; Clausell, Nadine; Corbalan, Ramon; Costanzo, Maria Rosa; Dickstein, Kenneth; Dunlap, Mark E; Ezekowitz, Justin A; Howlett, Jonathan G; Komajda, Michel; Krum, Henry; Lombardi, Carlo; Fonarow, Gregg C; McMurray, John J V; Nieminen, Markku S; Swedberg, Karl; Voors, Adriaan A; Starling, Randall C; Teerlink, John R; O'Connor, Christopher M

    2016-06-01

    A growing number of countries and geographical regions are involved in major clinical trials. Acute Study of Clinical Effectiveness of Nesiritide in Decompensated Heart Failure is the largest trial in acutely decompensated heart failure (HF) with patients from 5 geographical regions: North America (NA), Latin America (LA), Western Europe (WE), Central Europe (CE), and Asia-Pacific (AP). Data from the 5 geographical areas were compared including baseline characteristics, medications, 30-day outcomes (mortality and mortality or HF hospitalization), and 180-day mortality. Of the 7,141 study patients, 3,243 (45.4%) were from NA (average of 15.2 patients/site), 1,762 (24.7%) from AP (28.4 patients/site), 967 (13.5%) from CE (20.2 patients/site), 665 (9.3%) from LA (17.1 patients/site), and 504 (7.1%) from WE (14.4 patients/site). There were marked differences in co-morbidities, clinical profile, medication use, length of stay, 30-day event rates, and 180-day mortality by region. Compared with NA, the adjusted risk for death or HF hospitalization at 30 days was significantly lower in CE (odds ratio [OR] 0.46, 95% CI 0.33 to 0.64), WE (OR 0.52 95% CI 0.35 to 0.75), and AP (OR 0.62 95% CI 0.48 to 0.79) and numerically lower in LA (OR 0.77, 95% CI 0.57 to 1.04) with similar results for 180-day mortality. In conclusion, in patients with acutely decompensated HF, major differences in baseline characteristics, treatments, length of the hospital stay, and 30-day HF rehospitalization rates, and 180-day mortality were found in patients enrolled from different geographical areas. PMID:27108685

  4. Clinical Implications of Cluster Analysis-Based Classification of Acute Decompensated Heart Failure and Correlation with Bedside Hemodynamic Profiles

    PubMed Central

    Ahmad, Tariq; Desai, Nihar; Wilson, Francis; Schulte, Phillip; Dunning, Allison; Jacoby, Daniel; Allen, Larry; Fiuzat, Mona; Rogers, Joseph; Felker, G. Michael; O’Connor, Christopher; Patel, Chetan B.

    2016-01-01

    Background Classification of acute decompensated heart failure (ADHF) is based on subjective criteria that crudely capture disease heterogeneity. Improved phenotyping of the syndrome may help improve therapeutic strategies. Objective To derive cluster analysis-based groupings for patients hospitalized with ADHF, and compare their prognostic performance to hemodynamic classifications derived at the bedside. Methods We performed a cluster analysis on baseline clinical variables and PAC measurements of 172 ADHF patients from the ESCAPE trial. Employing regression techniques, we examined associations between clusters and clinically determined hemodynamic profiles (warm/cold/wet/dry). We assessed association with clinical outcomes using Cox proportional hazards models. Likelihood ratio tests were used to compare the prognostic value of cluster data to that of hemodynamic data. Results We identified four advanced HF clusters: 1) male Caucasians with ischemic cardiomyopathy, multiple comorbidities, lowest B-type natriuretic peptide (BNP) levels; 2) females with non-ischemic cardiomyopathy, few comorbidities, most favorable hemodynamics; 3) young African American males with non-ischemic cardiomyopathy, most adverse hemodynamics, advanced disease; and 4) older Caucasians with ischemic cardiomyopathy, concomitant renal insufficiency, highest BNP levels. There was no association between clusters and bedside-derived hemodynamic profiles (p = 0.70). For all adverse clinical outcomes, Cluster 4 had the highest risk, and Cluster 2, the lowest. Compared to Cluster 4, Clusters 1–3 had 45–70% lower risk of all-cause mortality. Clusters were significantly associated with clinical outcomes, whereas hemodynamic profiles were not. Conclusions By clustering patients with similar objective variables, we identified four clinically relevant phenotypes of ADHF patients, with no discernable relationship to hemodynamic profiles, but distinct associations with adverse outcomes. Our analysis

  5. Urinary Angiotensinogen Level Predicts AKI in Acute Decompensated Heart Failure: A Prospective, Two-Stage Study

    PubMed Central

    Yang, Xiaobing; Chen, Chunbo; Tian, Jianwei; Zha, Yan; Xiong, Yuqin; Sun, Zhaolin; Chen, Pingyan; Li, Jun; Yang, Tiecheng; Ma, Changsheng; Liu, Huafeng

    2015-01-01

    A major challenge in prevention and early treatment of acute cardiorenal syndrome (CRS) is the lack of high-performance predictors. To test the hypothesis that urinary angiotensinogen (uAGT) is an early predictor for acute CRS and 1-year prognosis in patients with acute decompensated heart failure (ADHF), we performed a prospective, two-stage, multicenter cohort study in patients with ADHF. In stage I (test set), 317 patients were recruited from four centers. In stage II (validation set), 119 patients were enrolled from two other centers. Daily uAGT levels were analyzed consecutively. AKI was defined according to Kidney Disease Improving Global Outcomes (KDIGO) Clinical Practice Guidelines. In stage I, 104 (32.8%) patients developed AKI during hospitalization. Daily uAGT peaked on the first hospital day in patients who subsequently developed AKI. After multivariable adjustment, the highest quartile of uAGT on admission was associated with a 50-fold increased risk of AKI compared with the lowest quartile. For predicting AKI, uAGT (area under the receiver-operating characteristic curve [AUC]=0.84) outperformed urinary neutrophil gelatinase-associated lipocalin (AUC=0.78), the urinary albumin/creatinine ratio (AUC=0.71), and the clinical model (AUC=0.77). Survivors in stage I were followed prospectively for 1 year after hospital discharge. The uAGT level independently predicted the risk of 1-year mortality (adjusted odds ratio, 4.5; 95% confidence interval, 2.1 to 9.5) and rehospitalization (adjusted odds ratio, 3.6; 95% confidence interval, 1.6 to 5.7). The ability of uAGT in predicting AKI was validated in stage II (AUC=0.79). In conclusion, uAGT is a strong predictor for acute CRS and 1-year prognosis in ADHF. PMID:25722365

  6. Cardiorenal interactions in acute decompensated heart failure: contemporary concepts facing emerging controversies.

    PubMed

    Kazory, Amir; Elkayam, Uri

    2014-12-01

    Simultaneous dysfunction of the heart and the kidney represents a distinct spectrum of disease states composed of complex clinical scenarios with adverse outcomes. Worsening renal function (WRF) in the setting of acute decompensated heart failure (ADHF) is one such clinical setup for which the underlying mechanisms are poorly understood. Apparent discrepancies exist between the emerging data on the cardiorenal interactions of patients with ADHF and contemporary concepts such as the low forward flow or the high backward pressure hypotheses. The findings of recent retrospective studies also suggest that apparent "improvement in renal function" might be yet another risk factor for untoward outcomes in this patient population, further challenging our current understanding of the cardiorenal interactions. Besides, these data do not seem to fully support our conventional thinking about other aspects of these interactions such as the independent adverse impact of WRF on the outcomes of patients with ADHF, pointing to congestion as a possibly overlooked factor. In this article, we provide an overview of these emerging controversial issues with the goal of identifying the areas where clinical research could be most helpful, because it is of paramount importance to characterize the pathways leading to WRF in ADHF to develop a mechanistically relevant management strategy. Although the paucity of data coupled with the complexity of this field precludes any firm conclusion, these discussions are meant to prompt clinicians and researchers to revisit a number of long-believed concepts surrounding the cardiorenal interactions in ADHF. PMID:25230240

  7. The glucocorticoid in acute decompensated heart failure: Dr Jekyll or Mr Hyde?

    PubMed

    Massari, Francesco; Mastropasqua, Filippo; Iacoviello, Massimo; Nuzzolese, Vincenzo; Torres, Daniele; Parrinello, Gaspare

    2012-03-01

    Glucocorticoid administration is not recommended in patients with heart failure because of its related sodium and fluid retention. However, previous experimental and clinical studies have demonstrated that glucocorticoids can also induce a diuretic effect and improve renal function in patients with acute decompensated heart failure (ADHF) with refractory diuretic resistance. We report the case of a 65-year-old man with a known diagnosis of aortic stenosis, systolic ventricular dysfunction, and chronic obstructive pulmonary disease who was admitted for ADHF. After 3 days, during which resistance to conventional therapy was observed, intravenous methylprednisolone (60 mg/d) was added to ongoing medical treatment. Three days after the onset of glucocorticoid therapy, daily urine volume progressively increased (up to 5.8 L/d). Concurrently, signs and symptoms of congestion improved, the weight and brain natriuretic peptide plasma levels decreased (−7 kg and −46%, respectively) and glomerular filtration rate increased (+26%). Bioimpedance vector analysis showed a net reduction of fluid content (from 88.4% to 73.6% of hydration at discharge). In conclusion, this case report suggests that in a patient with ADHF and congestion resistant to diuretic therapy, glucocorticoid administration is safe and associated with improvement in congestion, neurohormonal status, and renal function. These data support the possible usefulness of glucocorticoids in this setting. PMID:21406321

  8. Loop Diuretics in Acute Decompensated Heart Failure: Necessary? Evil? A Necessary Evil?

    PubMed Central

    Felker, G. Michael; O’Connor, Christopher M.; Braunwald, Eugene

    2009-01-01

    Acute decompensated heart failure (ADHF) is a common and highly morbid cardiovascular disorder. Most hospitalizations for ADHF are related to symptoms of congestion, and the vast majority of ADHF patients are treated with intravenous loop diuretics. Despite this nearly ubiquitous use, data supporting the safety and efficacy of loop diuretics in ADHF are limited, and controversy exists about the best way to use loop diuretics with regard to both dosing and means of administration (continuous infusion vs. intermittent boluses). We reviewed the data supporting the safety and efficacy of loop diuretics in patients with ADHF. A large body of observational literature suggests that loop diuretics, especially at higher doses, may be associated with increased mortality in patients with heart failure even after detailed adjustment for other measures of disease severity. Additionally, multiple small underpowered trials suggest that continuous infusion may be equivalent or superior to intermittent bolus dosing. In summary, there is a critical need to develop more robust data on the use of loop diuretics in ADHF. In that context, the NIH Heart Failure Clinical Research Network has begun the Diuretics Optimization Strategies Evaluation (DOSE) study, a multi-center, double-blind, randomized controlled trial that will enroll 300 patients with ADHF. The DOSE study will randomize patients using a 2 × 2 factorial design to low dose vs. high dose furosemide, and intermittent bolus vs. continuous infusion. Successful completion of the DOSE study will provide important data on the optimal clinical use of loop diuretics in ADHF. PMID:19750134

  9. Hospitalized patients with acute decompensated heart failure: recognition, risk stratification, and treatment review.

    PubMed

    Amin, Alpesh

    2008-11-01

    Acute decompensated heart failure (ADHF) has emerged as a major healthcare problem. It causes approximately 3% of all hospitalizations in the United States, with the direct medical cost of these hospitalizations estimated at $18.8 billion per year. Early recognition, risk stratification, and evidence-based treatment are crucial in reducing the morbidity, mortality, and costs associated with this disorder. Classic signs and symptoms of ADHF, such as rales, dyspnea, and peripheral edema, may be absent at hospital presentation and, even when present, are not specific to this disorder. As a result, serum B-type natriuretic peptide level is now used to rapidly and accurately detect ADHF. Multivariate analyses have identified renal dysfunction, hypotension, advanced age, hyponatremia, and comorbidities as significant and independent mortality risk factors. Based on these factors, mortality risk can be stratified from very low to very high using published algorithms that have been validated in independent populations. Evidence-based guidelines for the treatment of ADHF are available from both the European Society of Cardiology and the Heart Failure Society of America. In general, an intravenous loop diuretic, either alone or in combination with a vasodilator, is recommended as initial therapy in patients with volume overload, depending on the patient's clinical status. Use of inotropic agents should be limited to the small subset of patients with low-output syndrome and significant hypotension. In any event, frequent monitoring of clinical response is essential, with subsequent therapy determined by this response. Finally, focused patient education during hospitalization may help reduce readmissions for ADHF.

  10. Bedside lung ultrasound in the evaluation of acute decompensated heart failure.

    PubMed

    Leidi, Federica; Casella, Francesco; Cogliati, Chiara

    2016-06-01

    Dyspnea is a common presenting complaint in the emergency department (ED) and a leading cause of hospitalization in intensive care unit (ICU) and medical wards. Ultrasound (US) has traditionally been considered inadequate to explore the aerated lung. However, in the past 15 years LUS gained broader application, at least in part thanks to the interpretation of the artefacts generated by the interaction of US and lung structures/content. The total reflection of US beam occurring at the pleural level determines the artefactual image of the aerated lung: an homogenous 'foggy-like' picture under the pleural line. As the air content of the lungs decreases due to interstitial imbibition, deposition of collagen or presence of blood, vertical artefacts -arising from the pleural line and moving synchronously with the respiration- called B-lines appear. Multiple and bilateral B-lines identify the alveolar-interstitial syndrome (AIS). The most common cause of AIS is the wet lung: the more the congestion burden, the more the extent of the B-lines, which become confluent until the so-called white lung in case of pulmonary edema. Many studies showed a higher accuracy of LUS in diagnosing acute decompensated heart failure (ADHF) as compared to chest X-ray As recently shown, the integration of LUS to clinical assessment allow to differentiate cardiogenic dyspnea with sensitivity and specificity greater than 95 %. Moreover, LUS can easily detect pleural effusion -frequently present in ADHF-appearing as an anechoic area in the recumbent area of the thorax, delimited inferiorly by the diaphragmatic dome and superiorly by the aerated lung. PMID:26885846

  11. 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

  12. Impact of onset time of acute kidney injury on outcomes in patients with acute decompensated heart failure.

    PubMed

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

    2016-01-01

    Since acute kidney injury (AKI) is not always related to mortality in patients with acute decompensated heart failure (ADHF), the aim of this study was to focus on onset time of AKI and its clinical importance. A total of 371 ADHF patients were included. The impact of AKI (≥ 0.3 mg/dl or 1.5-fold increase in serum creatinine level within 48 h) with early onset (≤ 4 days from admission) or late onset (≥ 5 days from admission) was assessed. AKI occurred in 99 patients, who were divided into two groups according to the median onset time of AKI: 50 with early onset of AKI and 49 with late onset of AKI. The maximum increase in serum creatinine level from admission was greater in patients with late onset of AKI than in patients with early onset of AKI (p = 0.012). Patients with late onset of AKI had a higher 12-month mortality rate than that in patients with early onset of AKI (log-rank test, p = 0.014). Late onset of AKI was an independent predictor of mortality (hazard ratio: 3.39, 95 % confidence interval: 1.84-6.18, p < 0.001). Late onset of AKI was associated with high blood urea nitrogen level at admission and intravenous administration of dobutamine. In conclusion, late onset of AKI related to high blood urea nitrogen level and intravenous administration of dobutamine, but not early onset of AKI, is linked to high mortality rate. Onset time of AKI may be useful for risk stratification of mortality in ADHF patients developing AKI.

  13. Sex differences in clinical characteristics and long-term outcome in acute decompensated heart failure patients with preserved and reduced ejection fraction.

    PubMed

    Nakada, Yasuki; Kawakami, Rika; Nakano, Tomoya; Takitsume, Akihiro; Nakagawa, Hitoshi; Ueda, Tomoya; Nishida, Taku; Onoue, Kenji; Soeda, Tsunenari; Okayama, Satoshi; Takeda, Yukiji; Watanabe, Makoto; Kawata, Hiroyuki; Okura, Hiroyuki; Saito, Yoshihiko

    2016-04-01

    In patients with acute decompensated heart failure (ADHF), sex differences considering clinical and pathophysiologic features are not fully understood. We investigated sex differences in left ventricular (LV) ejection fraction (LVEF), plasma B-type natriuretic peptide (BNP) levels, and prognostic factors in patients with ADHF in Japan. We studied 748 consecutive ADHF patients of 821 patients registered in the ADHF registry between January 2007 and December 2014. Patients were divided into four groups based on sex and LVEF [reduced (ejection fraction, or EF, <50%, heart failure with reduced EF, or HFrEF) or preserved (EF ≥50%, heart failure with preserved LVEF, or HFpEF)]. The primary endpoint was the combination of cardiovascular death and heart failure (HF) admission. The present study consisted of 311 female patients (50% HFrEF, 50% HFpEF) and 437 male patients (63% HFrEF, 37% HFpEF). There was significant difference between sexes in the LVEF distribution profile. The ratio of HFpEF patients was significantly higher in female patients than in male patients (P= 0.0004). Although there were no significant sex differences in median plasma BNP levels, the prognostic value of BNP levels was different between sexes. Kaplan-Meier analysis revealed that the high BNP group had worse prognosis than the low BNP group in male but not in female patients. In multivariate analysis, log transformed BNP at discharge predicted cardiovascular events in male but not in female HF patients (female, hazard ratio: 1.169; 95% confidence interval: 0.981-1.399;P= 0.0806; male, hazard ratio: 1.289; 95% confidence interval: 1.120-1.481;P= 0.0004). In patients with ADHF, the distribution of LV function and the prognostic significance of plasma BNP levels for long-term outcome were different between the sexes.

  14. 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. PMID:27362779

  15. 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.

  16. 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

  17. 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

  18. 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

  19. 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

  20. Prognostic factors of mid-term clinical outcome in congestive heart failure patients discharged after acute decompensation

    PubMed Central

    Lombardo, Enrico; Testa, Marzia; Avogadri, Enrico; Piccolo, Salvatore; Vado, Antonello

    2012-01-01

    Introduction Risk stratification in congestive heart failure (CHF) patients is based on a variety of clinical and laboratory variables. We analysed renal function, BNP, water composition, echocardiographic and functional determinations in predicting mid-term outcome in CHF patients discharged after decompensation. Material and methods All subjects with NYHA class II-IV were enrolled at hospital discharge. NYHA class, BNP, water body composition, non-invasive cardiac output and echocardiogram were analysed. Death, cardiac transplantation and hospital readmission for CHF were scheduled. Results Two-hundred and thirty-seven (64.5% males, age 71.1±10.1) patients were discharged after obtaining normal hydration; left ventricular ejection fraction (LVEF) was 43.2±16.2%, cardiac output was 3.8±1.1 l/min and BNP at discharge resulted 401.3±501.7 pg/ml. During the 14-month follow-up 15 patients (6.3%) died, 1 (0.4%) underwent cardiac transplantation and 18 (7.6%) were readmitted for CHF (event group); in 203 (85.6%) no events were observed (no-event group). Higher NYHA class (2.1±0.7 vs. 1.9±0.4, p=0.01), BNP at discharge (750.2±527.3 pg/ml vs. 340.7±474.3 pg/ml, p=0.002) and impaired LVEF (33.7±15.7% vs. 44.5±15.8%, p=0.0001) and creatinine (1.7±0.6 vs. 1.2±0.8 mg/dl, p=0.004) were noticed in the event group. At multivariate Cox analysis LVEF (p=0.0009), plasma creatinine (p=0.006) and BNP at discharge (p=0.001) were associated with adverse mid-term outcome. Kaplan-Meier survival curves demonstrated that adding cut-off points for creatinine 1.5 mg/dl and discharged BNP of 250 pg/ml discriminated significantly prognosis (p=0.0001; log rank 21.09). Conclusions In predicting mid-term clinical prognosis in CHF patients discharged after acute decompensation, BNP at discharge ≥ 250 pg/ml added with plasma creatinine > 1.5 mg/dl are strong adverse predictors. PMID:22852001

  1. Mood, Th-1/Th-2 cytokine profile, and autonomic activity in older adults with acute/decompensated heart failure: preliminary observations.

    PubMed

    Guinjoan, Salvador M; Vigo, Daniel E; Castro, Mariana N; Tateosian, Nancy; Chuluyan, Eduardo; Costanzo, Elsa; Fahrer, Rodolfo; Grancelli, Hugo; Leiguarda, Ramón; Cardinali, Daniel P

    2009-01-01

    In order to assess the relationships among mood, peripheral autonomic output and circulating immunoinflammatory mediators in older individuals with decompensated heart failure (CHF), 20 consecutive patients (78+/-7 years, 35% women) admitted to the coronary care unit with a clinical diagnosis of acute/decompensated CHF of coronary origin were examined. Mood was evaluated by the 21-item Hamilton Depression Scale (HAM-D). Four patients met the criteria for major depression. Heart rate variability (HRV) analysis and the levels of tumour necrosis factor (TNF)-alpha, interferon (IFN)-gamma, interleukin (IL)-2, IL-4, IL-6 and IL-10 were measured within 24-72 h of admission. A significant positive relationship between score in HAM-D and serum IL-6 levels was detected with a similar trend as far as IL-2 levels. Circulating IL-2 levels were strongly associated with the HRV L/H quotient, an index of increased sympathetic and/or decreased parasympathetic thoracic activity. A negative correlation between vagal activity (as assessed by HRV) and IL-4 occurred. Neither TNF-alpha nor IL-10 were detectable in this group of elderly patients. The results add to the concept that mood and autonomic unbalance are associated with increased systemic inflammation in old patients with decompensated CHF, a potential mechanism for mood-related worsened prognosis of heart failure at an advanced age.

  2. Ventricular conduction abnormalities as predictors of long‐term survival in acute de novo and decompensated chronic heart failure

    PubMed Central

    Siirila‐Waris, Krista; Harjola, Veli‐Pekka; Marono, David; Parenica, Jiri; Kreutzinger, Philipp; Nieminen, Tuomo; Pavlusova, Marie; Tarvasmaki, Tuukka; Twerenbold, Raphael; Tolonen, Jukka; Miklik, Roman; Nieminen, Markku S.; Spinar, Jindrich; Mueller, Christian; Lassus, Johan

    2016-01-01

    Abstract Aims Data on the prognostic role of left and right bundle branch blocks (LBBB and RBBB), and nonspecific intraventricular conduction delay (IVCD; QRS ≥ 110 ms, no BBB) in acute heart failure (AHF) are controversial. Our aim was to investigate electrocardiographic predictors of long‐term survival in patients with de novo AHF and acutely decompensated chronic heart failure (ADCHF). Methods and Results We analysed the admission electrocardiogram of 982 patients from a multicenter European cohort of AHF with 3.9 years' mean follow‐up. Half (51.5%, n = 506) of the patients had de novo AHF. LBBB, and IVCD were more common in ADCHF than in de novo AHF: 17.2% vs. 8.7% (P < 0.001) and 20.6% vs. 13.2% (P = 0.001), respectively, and RBBB was almost equally common (6.9% and 8.1%; P = 0.5), respectively. Mortality during the follow‐up was higher in patients with RBBB (85.4%) and IVCD (73.7%) compared with patients with normal ventricular conduction (57.0%); P < 0.001 for both. The impact of RBBB on prognosis was prominent in de novo AHF (adjusted HR 1.93, 1.03–3.60; P = 0.04), and IVCD independently predicted death in ADCHF (adjusted HR 1.79, 1.28–2.52; P = 0.001). Both findings were pronounced in patients with reduced ejection fraction. LBBB showed no association with increased mortality in either of the subgroups. The main results were confirmed in a validation cohort of 1511 AHF patients with 5.9 years' mean follow‐up. Conclusions Conduction abnormalities predict long‐term survival differently in de novo AHF and ADCHF. RBBB predicts mortality in de novo AHF, and IVCD in ADCHF. LBBB has no additive predictive value in AHF requiring hospitalization.

  3. [Hepatorenal syndrome in decompensated cirrhosis : A special form of acute renal failure].

    PubMed

    Lenz, K; Buder, R; Lohr, G; Piringer, P; Voglmayr, M

    2016-06-01

    Renal failure is a serious complication in patients with advanced cirrhosis. It occurs in about 20 % of patients hospitalized with cirrhosis. In about 70 % it is caused by prerenal failure, and in 30 % it is due to intrarenal causes. In about 70 % of patients with rperenal failure, renal function can be restored with fluid replacement, but the remaining 30 % are unresponsive to volume expansion. Minor increase in serum creatinine have been shown to be clinically relevant and can adversely affect survival. Therefore early efforts should be made to avoid precipitation of renal failure.Hepatorenal syndrome (HRS) is a  fully reversible impairment of renal function in patients with cirrhosis unresponsive to volume expansion characterized by an acute progressive decrease in kidney function (serumcreatinin > 1,5 mg/dl) - type 1 HRS, whereas type 2 HRS features a decrease in kidney function over a long time, mostly in patients with refractory ascites. Therapy with vasoconstrictors like terlipressin to reverse splanchnic vasodilation, together with albumin is effective in 30-50 % of patients with HRS 1 and improves survival. The only effective longterm therapy is livertransplantation. An improvement of kidney fuction before transplantation is associated with a better outcome and posttransplant kidney function.

  4. 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

  5. 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

  6. 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

  7. Impact of changes in blood pressure during the treatment of acute decompensated heart failure on renal and clinical outcomes†

    PubMed Central

    Testani, Jeffrey M.; Coca, Steven G.; McCauley, Brian D.; Shannon, Richard P.; Kimmel, Stephen E.

    2011-01-01

    Aims One of the primary determinants of blood flow in regional vascular beds is perfusion pressure. Our aim was to investigate if reduction in blood pressure during the treatment of decompensated heart failure would be associated with worsening renal function (WRF). Our secondary aim was to evaluate the prognostic significance of this potentially treatment-induced form of WRF. Methods and results Subjects included in the Evaluation Study of Congestive Heart Failure and Pulmonary Artery Catheterization Effectiveness (ESCAPE) trial limited data were studied (386 patients). Reduction in systolic blood pressure (SBP) was greater in patients experiencing WRF (−10.3 ± 18.5 vs. −2.8 ± 16.0 mmHg, P < 0.001) with larger reductions associated with greater odds for WRF (odds ratio = 1.3 per 10 mmHg reduction, P < 0.001). Systolic blood pressure reduction (relative change > median) was associated with greater doses of in-hospital oral vasodilators (P ≤ 0.017), thiazide diuretic use (P = 0.035), and greater weight reduction (P = 0.023). In patients with SBP-reduction, WRF was not associated with worsened survival [adjusted hazard ratio (HR) = 0.76, P = 0.58]. However, in patients without SBP-reduction, WRF was strongly associated with increased mortality (adjusted HR = 5.3, P < 0.001, P interaction = 0.001). Conclusion During the treatment of decompensated heart failure, significant blood pressure reduction is strongly associated with WRF. However, WRF that occurs in the setting of SBP-reduction is not associated with an adverse prognosis, whereas WRF in the absence of this provocation is strongly associated with increased mortality. These data suggest that WRF may represent the final common pathway of several mechanistically distinct processes, each with potentially different prognostic implications. PMID:21693504

  8. 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.

  9. Impact of predischarge nocturnal pulse oximetry (sleep-disordered breathing) on postdischarge clinical outcomes in hospitalized patients with left ventricular systolic dysfunction after acute decompensated heart failure.

    PubMed

    Ohmura, Takayasu; Iwama, Yoshitaka; Kasai, Takatoshi; Kato, Takao; Suda, Shoko; Takagi, Atsutoshi; Daida, Hiroyuki

    2014-02-15

    Stratifying patients at a high risk for readmission and mortality before their discharge after acute decompensated heart failure (ADHF) is important. Although sleep-disordered breathing (SDB) is prevalent in patients with chronic heart failure, only few studies have investigated the impact of SDB on hospitalized patients with left ventricular (LV) systolic dysfunction after ADHF. Thus, we assessed the prevalence of SDB using nocturnal pulse oximetry and the relation between SDB and clinical events in this patient group. One hundred consecutive patients with LV systolic dysfunction who were hospitalized for ADHF were enrolled in the study. Predischarge nocturnal oximetry was performed to determine if they had SDB (defined as an oxygen desaturation index of ≥5 events/hour with ≥4% decrease in saturation level). Data on death and readmission for ADHF were collected. Forty-one patients had SDB. Complete outcome data were collected in the mean follow-up period of 14.2 months during which 33 events occurred. On multivariate Cox proportional hazards regression analysis, the presence of SDB was a significant independent predictor of postdischarge readmission and mortality (hazard ratio 2.93, p = 0.006). In conclusion, SDB, as determined by predischarge nocturnal oximetry, is prevalent and is an independent predictor of the combined end point of readmission and mortality in hospitalized patients with LV systolic dysfunction after ADHF.

  10. Acute liver function decompensation in a patient with sickle cell disease managed with exchange transfusion and endoscopic retrograde cholangiography

    PubMed Central

    Ona, Mel A.; Changela, Kinesh; Sadanandan, Swayamprabha; Jelin, Abraham; Anand, Sury; Duddempudi, Sushil

    2014-01-01

    Sickle cell intrahepatic cholestasis is a relatively uncommon complication of homozygous sickle cell anemia, which may lead to acute hepatic failure and death. Treatment is mainly supportive, but exchange transfusion is used as salvage therapy in life threatening situations. We describe a case of a 16-year-old female with homozygous sickle cell anemia who presented to the emergency room with fatigue, malaise, dark urine, lower back pain, scleral icterus and jaundice. She was found to have marked hyperbilirubinemia, which persisted after exchange transfusion. Because of the concomitant presence of gallstones and choledocholithiasis, the patient underwent endoscopic ultrasound and laparoscopic cholecystectomy followed by endoscopic retrograde cholangiography and sphincterotomy. PMID:25177368

  11. Worsening of Renal Function During 1 Year After Hospital Discharge Is a Strong and Independent Predictor of All‐Cause Mortality in Acute Decompensated Heart Failure

    PubMed Central

    Ueda, Tomoya; Kawakami, Rika; Sugawara, Yu; Okada, Sadanori; Nishida, Taku; Onoue, Kenji; Soeda, Tsunenari; Okayama, Satoshi; Takeda, Yukiji; Watanabe, Makoto; Kawata, Hiroyuki; Uemura, Shiro; Saito, Yoshihiko

    2014-01-01

    Background Renal impairment is a common comorbidity and the strongest risk factor for poor prognosis in acute decompensated heart failure (ADHF). In clinical practice, renal function is labile during episodes of ADHF, and often worsens after discharge. The significance of worsening of renal function (WRF) after discharge has not been investigated as extensively as baseline renal function at admission or WRF during hospitalization. Methods and Results Among 611 consecutive patients with ADHF emergently admitted to our hospital, 233 patients with 3 measurements of serum creatinine (SCr) level measurements (on admission, at discharge, and 1 year after discharge) were included in the present study. Patients were divided into 2 groups according to the presence or absence of WRF at 1 year after discharge (1y‐WRF), defined as an absolute increase in SCr >0.3 mg/dL (>26.5 μmol/L) plus a ≥25% increase in SCr at 1 year after discharge compared to the SCr value at discharge. All‐cause and cardiovascular mortality were assessed as adverse outcomes. During a mean follow‐up of 35.4 months, 1y‐WRF occurred in 48 of 233 patients. There were 66 deaths from all causes. All‐cause and cardiovascular mortality were significantly higher in patients with 1y‐WRF (log‐rank P<0.0001 and P<0.0001, respectively) according to Kaplan–Meier analysis. In a multivariate Cox proportional hazards model, 1y‐WRF was a strong and independent predictor of all‐cause and cardiovascular mortality. Hemoglobin and B‐type natriuretic peptide at discharge, as well as left ventricular ejection fraction <50%, were independent predictors of 1y‐WRF. Conclusions In patients with ADHF, 1y‐WRF is a strong predictor of all‐cause and cardiovascular mortality. PMID:25370599

  12. Optimizing fluid management in patients with acute decompensated heart failure (ADHF): the emerging role of combined measurement of body hydration status and brain natriuretic peptide (BNP) levels.

    PubMed

    Valle, Roberto; Aspromonte, Nadia; Milani, Loredano; Peacock, Frank W; Maisel, Alan S; Santini, Massimo; Ronco, Claudio

    2011-11-01

    The study tests the hypothesis that in patients admitted with acutely decompensated heart failure (ADHF), achievement of adequate body hydration status with intensive medical therapy, modulated by combined bioelectrical vectorial impedance analysis (BIVA) and B-type natriuretic peptide (BNP) measurement, may contribute to optimize the timing of patient's discharge and to improve clinical outcomes. Three hundred patients admitted for ADHF underwent serial BIVA and BNP measurement. Therapy was titrated to reach a BNP value of <250 pg/ml, whenever possible. Patients were categorized as early responders (rapid BNP fall below 250 pg/ml); late responders (slow BNP fall below 250 pg/ml, after aggressive therapy); and non-responders (BNP persistently >250 pg/ml). Worsening of renal function (WRF) was evaluated during hospitalization. Death and rehospitalization were monitored with a 6-month follow-up. BNP value on discharge of ≤250 pg/ml led to a 25% event rate within 6 months (Group A: 17.4%; Group B: 21%, Chi2; n.s.), whereas a value >250 pg/ml (Group C) was associated with a far higher percentage (37%). At discharge, body hydration was 73.8 ± 3.2% in the total population and 73.2 ± 2.1, 73.5 ± 2.8, 74.1 ± 3.6% in the three groups, respectively. WRF was observed in 22.3% of the total. WRF occurred in 22% in Group A, 32% in Group B, and 20% in Group C (P = n.s.). Our study confirms the hypothesis that combined BNP/BIVA sequential measurements help to achieve adequate fluid balance status in patients with ADHF and can be used to drive a "tailored therapy," allowing clinicians to identify high-risk patients and possibly to reduce the incidence of complications secondary to fluid management strategies.

  13. 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

  14. 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

  15. 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.

  16. 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

  17. [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.

  18. Reduced SIRT1 expression correlates with enhanced oxidative stress in compensated and decompensated heart failure.

    PubMed

    Akkafa, Feridun; Halil Altiparmak, Ibrahim; Erkus, Musluhittin Emre; Aksoy, Nurten; Kaya, Caner; Ozer, Ahmet; Sezen, Hatice; Oztuzcu, Serdar; Koyuncu, Ismail; Umurhan, Berrin

    2015-12-01

    Sirtuin-1 (SIRT1) is a longevity factor in mammals initiating the cell survival mechanisms, and preventing ischemic injury in heart. In the etiopathogenesis of heart failure (HF), impairment in cardiomyocyte survival is a notable factor. Oxidative stress comprises a critical impact on cardiomyocyte lifespan in HF. The aim of the present study was to investigate SIRT1 expression in patients with compensated (cHF) and decompensated HF (dHF), and its correlation with oxidative stress. SIRT1 expression in peripheral leukocytes was examined using quantitative RT-PCR in 163 HF patients and 84 controls. Serum total oxidant status (TOS) and total antioxidant status (TAS) were measured via colorimetric assays, and oxidative stress index (OSI) was calculated. Lipid parameters were also determined by routine laboratory methods. SIRT1 mRNA expression was significantly downregulated in HF with more robust decrease in dHF (p=0.002, control vs cHF; p<0.001, control vs dHF). Markedly increased oxidative stress defined as elevated TOS, OSI and low TAS levels were detected in HF patients comparing with the controls (TAS; p=0.010, control vs cHF, p=0.045 control vs dHF, TOS; p=0.004 control vs cHF; p<0.001 control vs dHF, OSI; p<0.001 for both comparisons, respectively). With SIRT1 expression levels, TAS, TOS, OSI, and high density lipoprotein levels in cHF and dHF were determined correlated. SIRT1 expression were significantly reduced in both HF subtypes, particularly in dHF. SIRT1 expression was correlated with the oxidant levels and antioxidant capacity. Data suggest that SIRT1 may have a significant contribution in regulation of oxidant/antioxidant balance in HF etiology and compensation status. PMID:26233702

  19. Nightmares and psychotic decompensation: a case study.

    PubMed

    Levin, R; Daly, R S

    1998-01-01

    There have been numerous reports in the literature on the descriptive similarities between a severe nightmare and an acute psychotic episode. Nightmares may be a prelude to psychotic decompensation, and it has been suggested that frequent lifelong nightmares may even be diagnostic of an underlying vulnerability to psychosis. In this report, we present a case study of a 40-year old female experiencing chronic paranoid schizophrenia, whose two witnessed psychotic relapses in the hospital were immediately preceded by intense and vivid nightmare attacks. Significantly, the content of these nocturnal dreams was thematically consistent with her waking hallucinations, suggesting a direct continuity between these experiences. We propose that further systematic study of the dreams and nightmares of individuals diagnosed with schizophrenia may be particularly useful in understanding their phenomenological experience.

  20. 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

  1. Canadian Cardiovascular Society Consensus Conference recommendations on heart failure update 2007: Prevention, management during intercurrent illness or acute decompensation, and use of biomarkers

    PubMed Central

    Arnold, J Malcolm O; Howlett, Jonathan G; Dorian, Paul; Ducharme, Anique; Giannetti, Nadia; Haddad, Haissam; Heckman, George A; Ignaszewski, Andrew; Isaac, Debra; Jong, Philip; Liu, Peter; Mann, Elizabeth; McKelvie, Robert S; Moe, Gordon W; Parker, John D; Svendsen, Anna M; Tsuyuki, Ross T; O’Halloran, Kelly; Ross, Heather J; Rao, Vivek; Sequeira, Errol J; White, Michel

    2007-01-01

    Heart failure is common, yet it is difficult to treat. It presents in many different guises and circumstances in which therapy needs to be individualized. The Canadian Cardiovascular Society published a comprehensive set of recommendations in January 2006 on the diagnosis and management of heart failure, and the present update builds on those core recommendations. Based on feedback obtained through a national program of heart failure workshops during 2006, several topics were identified as priorities because of the challenges they pose to health care professionals. New evidence-based recommendations were developed using the structured approach for the review and assessment of evidence adopted and previously described by the Society. Specific recommendations and practical tips were written for the prevention of heart failure, the management of heart failure during intercurrent illness, the treatment of acute heart failure, and the current and future roles of biomarkers in heart failure care. Specific clinical questions that are addressed include: which patients should be identified as being at high risk of developing heart failure and which interventions should be used? What complications can occur in heart failure patients during an intercurrent illness, how should these patients be monitored and which medications may require a dose adjustment or discontinuation? What are the best therapeutic, both drug and nondrug, strategies for patients with acute heart failure? How can new biomarkers help in the treatment of heart failure, and when and how should BNP be measured in heart failure patients? The goals of the present update are to translate best evidence into practice, to apply clinical wisdom where evidence for specific strategies is weaker, and to aid physicians and other health care providers to optimally treat heart failure patients to result in a measurable impact on patient health and clinical outcomes in Canada. PMID:17245481

  2. 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.

  3. Change of Serum BNP Between Admission and Discharge After Acute Decompensated Heart Failure Is a Better Predictor of 6-Month All-Cause Mortality Than the Single BNP Value Determined at Admission

    PubMed Central

    De Vecchis, Renato; Ariano, Carmelina; Giandomenico, Giuseppe; Di Maio, Marco; Baldi, Cesare

    2016-01-01

    Background B-type natriuretic peptide (BNP) is regarded as a reliable predictor of outcome in patients with acute decompensated heart failure (ADHF). However, according to some scholars, a single isolated measurement of serum BNP at the time of hospital admission would not be sufficient to provide reliable prognostic information. Methods A retrospective study was carried out on patients hospitalized for ADHF, who had then undergone follow-up of at least 6 months, in order to see if there was any difference in midterm mortality among patients with rising BNP at discharge as compared to those with decreasing BNP at discharge. Medical records had to be carefully examined to divide the case records into two groups, the former characterized by an increase in BNP during hospitalization, and the latter showing a decrease in BNP from the time of admission to the time of discharge. Results Ultimately, 177 patients were enrolled in a retrospective study. Among them, 53 patients (29.94%) had increased BNPs at the time of discharge relative to admission, whereas 124 (70.06%) exhibited decreases in serum BNP during their hospital stay. The group with patients who exhibited BNP increases at the time of discharge had higher degree of congestion evident in the higher frequency of persistent jugular venous distention (odds ratio: 3.72; P = 0.0001) and persistent orthopnea at discharge (odds ratio: 2.93; P = 0.0016). Moreover, patients with increased BNP at the time of discharge had a lower reduction in inferior vena cava maximum diameter (1.58 ± 2.2 mm vs. 6.32 ± 1.82 mm; P = 0.001 (one-way ANOVA)). In contrast, there was no significant difference in weight loss when patients with increased BNP at discharge were compared to those with no such increase. A total of 14 patients (7.9%) died during the 6-month follow-up period. Cox proportional hazard analysis revealed that BNP increase at the time of discharge was an independent predictor of 6-month all-cause mortality after

  4. Change of Serum BNP Between Admission and Discharge After Acute Decompensated Heart Failure Is a Better Predictor of 6-Month All-Cause Mortality Than the Single BNP Value Determined at Admission

    PubMed Central

    De Vecchis, Renato; Ariano, Carmelina; Giandomenico, Giuseppe; Di Maio, Marco; Baldi, Cesare

    2016-01-01

    Background B-type natriuretic peptide (BNP) is regarded as a reliable predictor of outcome in patients with acute decompensated heart failure (ADHF). However, according to some scholars, a single isolated measurement of serum BNP at the time of hospital admission would not be sufficient to provide reliable prognostic information. Methods A retrospective study was carried out on patients hospitalized for ADHF, who had then undergone follow-up of at least 6 months, in order to see if there was any difference in midterm mortality among patients with rising BNP at discharge as compared to those with decreasing BNP at discharge. Medical records had to be carefully examined to divide the case records into two groups, the former characterized by an increase in BNP during hospitalization, and the latter showing a decrease in BNP from the time of admission to the time of discharge. Results Ultimately, 177 patients were enrolled in a retrospective study. Among them, 53 patients (29.94%) had increased BNPs at the time of discharge relative to admission, whereas 124 (70.06%) exhibited decreases in serum BNP during their hospital stay. The group with patients who exhibited BNP increases at the time of discharge had higher degree of congestion evident in the higher frequency of persistent jugular venous distention (odds ratio: 3.72; P = 0.0001) and persistent orthopnea at discharge (odds ratio: 2.93; P = 0.0016). Moreover, patients with increased BNP at the time of discharge had a lower reduction in inferior vena cava maximum diameter (1.58 ± 2.2 mm vs. 6.32 ± 1.82 mm; P = 0.001 (one-way ANOVA)). In contrast, there was no significant difference in weight loss when patients with increased BNP at discharge were compared to those with no such increase. A total of 14 patients (7.9%) died during the 6-month follow-up period. Cox proportional hazard analysis revealed that BNP increase at the time of discharge was an independent predictor of 6-month all-cause mortality after

  5. Clinical features of patients with decompensated heart failure after the Great East Japan Earthquake.

    PubMed

    Yamauchi, Hiroyuki; Yoshihisa, Akiomi; Iwaya, Shoji; Owada, Takashi; Sato, Takamasa; Suzuki, Satoshi; Yamaki, Takayoshi; Sugimoto, Koichi; Kunii, Hiroyuki; Nakazato, Kazuhiko; Suzuki, Hitoshi; Saitoh, Shu-ichi; Takeishi, Yasuchika

    2013-07-01

    The occurrence of heart failure (HF) and its clinical features after a great disaster have not been rigorously examined. We retrospectively examined the effect of the Great East Japan Earthquake on the occurrence of decompensated HF. The number of patients admitted for treatment of decompensated HF and their clinical features were compared between 2 periods, March 11, 2011 to September 10, 2011 (after the earthquake) and the same period in the previous year. The number of admissions increased from 55 in 2010 to 84 in 2011. A comparison of the clinical features showed that the patients admitted after the earthquake had (1) older age (p = 0.031), (2) greater systolic blood pressure (p = 0.039), (3) a greater incidence of new-onset HF due to valvular heart disease (p = 0.040), (4) interruption of drugs (p = 0.001), (5) a greater incidence of infection (p = 0.019), (6) greater B-type natriuretic peptide (p = 0.005) and C-reactive protein (p = 0.003) levels, (7) a lower estimated glomerular filtration rate (p = 0.048) and lower albumin levels (p = 0.021), and (8) a larger diameter of the inferior vena cava (p = 0.008). In conclusion, these results suggest that the earthquake increased the incidence of HF in association with high blood pressure, interruption of drugs, inflammation, malnutrition, and fluid retention. Taking appropriate measures to control blood pressure, nutritional status, and hygiene environment might decrease the occurrence of HF in future disasters.

  6. [Bibliotherapeutic dream work after acute psychotic decompensation].

    PubMed

    Klosinski, G

    1996-01-01

    The paper reports about a follow-up treatment of a 15,5 year old female youth, who had suffered a polymorph psychotic disturbance with schizophrenic symptomatology. The symptoms began after a sexual encounter with a friend. During her illness the patient considered herself as "Jesus". By means of intensive dream work and bibliotherapy the psychotic events could be identified and understood subjectively. Three months after the onset of the illness the psychotic anxieties could be addressed by reading the Grimm fairy tale "The robber's bride" and could thus be better understood and classified. The patient's anxieties referred to physical and emotional disintegration (to be incorporated, to be Christ himself, and to give away his body). The patient could recall these anxieties as having actually occurred to her at the beginning of her illness.

  7. Decreased accommodation during decompensation of distance exotropia

    PubMed Central

    Horwood, Anna M; Riddell, Patricia M

    2015-01-01

    Objective Disparity cues can be a major drive to accommodation via the CA/C (convergence accommodation to convergence) linkage but, on decompensation of exotropia, disparity cues are extinguished by suppression, so this drive is lost. This study investigated accommodation and vergence responses to disparity, blur and proximal cues in a group of distance exotropes aged between 4-11 years both during decompensation and when exotropic. Methods 19 participants with distance exotropia were tested using a PlusoptiXSO4 photorefractor set in a remote haploscopic device which assessed simultaneous vergence and accommodation to a range of targets incorporating different combinations of blur, disparity and proximal cues at four fixation distances between 2m and 33cm. Responses on decompensation were compared to those from the same children when their deviation was controlled. Results Manifest exotropia was more common in the more impoverished cue conditions. When decompensated for near, mean accommodation gain for the all-cue (naturalistic) target reduced significantly (p<0.0001), with resultant mean under-accommodation of 2.33D at 33cm. The profile of near cues usage changed after decompensation, with blur and proximity driving residual responses, but these remaining cues did not compensate for loss of accommodation caused by the removal of disparity. Conclusions Accommodation often reduces on decompensation of distance exotropia as the drive from convergence is extinguished, providing a further reason to try to prevent decompensation for near. PMID:21873311

  8. Enlarging Red Blood Cell Distribution Width During Hospitalization Identifies a Very High-Risk Subset of Acutely Decompensated Heart Failure Patients and Adds Valuable Prognostic Information on Top of Hemoconcentration

    PubMed Central

    Ferreira, João Pedro; Girerd, Nicolas; Arrigo, Mattia; Medeiros, Pedro Bettencourt; Ricardo, Miguel Bento; Almeida, Tiago; Rola, Alexandre; Tolpannen, Heli; Laribi, Said; Gayat, Etienne; Mebazaa, Alexandre; Mueller, Christian; Zannad, Faiez; Rossignol, Patrick; Aragão, Irene

    2016-01-01

    Abstract Red blood cell distribution width (RDW) may serve as an integrative marker of pathological processes that portend worse prognosis in heart failure (HF). The prognostic value of RDW variation (ΔRDW) during hospitalization for acute heart failure (AHF) has yet to be studied. We retrospectively analyzed 2 independent cohorts: Centro Hospitalar do Porto (derivation cohort) and Lariboisière hospital (validation cohort). In the derivation cohort a total of 170 patients (age 76.2 ± 10.3 years) were included and in the validation cohort 332 patients were included (age 76.4 ± 12.2 years). In the derivation cohort the primary composite outcome of HF admission and/or cardiovascular death occurred in 78 (45.9%) patients during the 180-day follow-up period. Discharge RDW and ΔRDW were both increased when hemoglobin levels were lower; peripheral edema was also associated with increased discharge RDW (all P < 0.05). Discharge RDW value was significantly associated with adverse events: RDW > 15% at discharge was associated with a 2-fold increase in event rate, HR = 1.95 (1.05–3.62), P = 0.04, while a ΔRDW >0 also had a strong association with outcome, HR = 2.47 (1.35–4.51), P = 0.003. The addition of both discharge RDW > 15% and ΔRDW > 0 to hemoconcentration was associated with a significant improvement in the net reclassification index, NRI = 18.3 (4.3–43.7), P = 0.012. Overlapping results were found in the validation cohort. As validated in 2 independent AHF cohorts, an in-hospital RDW enlargement and an elevated RDW at discharge are associated with increased rates of mid-term events. RDW variables improve the risk stratification of these patients on top of well-established prognostic markers. PMID:27057905

  9. Association of gender and length of stay among Puerto Ricans hospitalized with decompensated heart failure.

    PubMed

    Alnajashi, Mohammad A; Almasoud, Mohammed A; Aldaham, Sami A; Acuña, Juan Manuel; Zevallos, Juan C

    2016-07-01

    Heart failure (HF) is a serious, chronic, and progressive condition which may require hospitalization if decompensated. Each year, in the UnitedStates, there are approximately 1 million hospitalizations due to decompensated HF at a cost of $39 billion. Because limited information examining the association between gender and length of stay (LOS) is available in the published literature for Puerto Ricans hospitalized with decompensated HF, we aim to investigate gender differences related to LOS in this population.This study is a secondary data analysis of the Puerto Rico Cardiovascular Disease Surveillance System database, which is a nonconcurrent prospective study carried out in 2007 and 2009. LOS was dichotomized into ≤5 days or ≥6 days (extended) categories. The χ test was used to examine associations between categorical variables. Binary logistic regression was used to estimate unadjusted and adjusted odds ratios of extended LOS. Collinearity was assessed using Pearson correlation coefficients. A P value of 0.05 and 95% confidence intervals were used to evaluate statistical significance.A total of 1724 patients (47.6% women) comprised our study population. The average age of women was 72.5 ± 13.4 years; the average age of men was 67.2 ± 14.5 years. For both women and men, median LOS was 5 days (interquartile range = 5 days). Women were more likely than men to have diabetes mellitus, hypertension, and dyslipidemia, but current smoking was higher in men than in women. The proportion of patients with extended LOS was similar for men (43.3%) and women (45.1%) (P = 0.448). Likewise, the odds for extended LOS was comparable for both genders (OR = 1.1, 95% CI = 0.9, 1.4). Patients admitted with recurrent decompensated HF hospitalizations had shorter LOS than patients with initial episodes (OR = 0.7, 95% CI = 0.6, 0.9). However, factors that prolonged the LOS included the presence of renal failure (OR = 1.7; 95% IC = 1.3, 2

  10. A Pharmacogenetic Investigation of Intravenous Furosemide in Decompensated Heart Failure: A Meta-Analysis of 3 Clinical Trials

    PubMed Central

    de Denus, Simon; Rouleau, Jean L; Mann, Douglas L.; Huggins, Gordon S.; Cappola, Thomas P.; Shah, Svati H.; Keleti, Julianna; Zada, Yassamin Feroz; Provost, Sylvie; Bardhadi, Amina; Phillips, Michael S.; Normand, Valérie; Mongrain, Ian; Dubé, Marie-Pierre

    2016-01-01

    We conducted a meta-analysis of pharmacogenomic substudies of three randomized trials conducted in patients with decompensated heart failure (HF) which were led by National Heart Lung and Blood Institute (NHLBI)-funded HF Network to test the hypothesis that candidate genes modulate net fluid loss and weight change in patients with decompensated HF treated with a furosemide-based diuretic regimen. Although none of the genetic variants previously shown to modulate the effects of loop diuretics in healthy individuals were associated with net fluid loss after 72 hours of treatment, a set of rare variants in the APOL1 gene, which codes for apolipoprotein L1 (P= 0.0005 in the random effects model) was associated with this endpoint. Moreover, a common variant in the multidrug resistance protein-4 coding gene (ABCC4, rs17268282) was associated with weight loss with furosemide use (P = 0.0001). Our results suggest that both common and rare genetic variants modulate the response to a furosemide-based diuretic regimen in patients with decompensated HF. PMID:26927285

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

    PubMed Central

    2015-01-01

    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 m2) 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 m2, 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. PMID:25931787

  12. Biomarkers in acute heart failure.

    PubMed

    Mallick, Aditi; Januzzi, James L

    2015-06-01

    The care of patients with acutely decompensated heart failure is being reshaped by the availability and understanding of several novel and emerging heart failure biomarkers. The gold standard biomarkers in heart failure are B-type natriuretic peptide and N-terminal pro-B-type natriuretic peptide, which play an important role in the diagnosis, prognosis, and management of acute decompensated heart failure. Novel biomarkers that are increasingly involved in the processes of myocardial injury, neurohormonal activation, and ventricular remodeling are showing promise in improving diagnosis and prognosis among patients with acute decompensated heart failure. These include midregional proatrial natriuretic peptide, soluble ST2, galectin-3, highly-sensitive troponin, and midregional proadrenomedullin. There has also been an emergence of biomarkers for evaluation of acute decompensated heart failure that assist in the differential diagnosis of dyspnea, such as procalcitonin (for identification of acute pneumonia), as well as markers that predict complications of acute decompensated heart failure, such as renal injury markers. In this article, we will review the pathophysiology and usefulness of established and emerging biomarkers for the clinical diagnosis, prognosis, and management of acute decompensated heart failure.

  13. How much incisor decompensation is achieved prior to orthognathic surgery?

    PubMed Central

    McNeil, Calum; Laverick, Sean

    2014-01-01

    Objectives: To quantify incisor decompensation in preparation for orthognathic surgery. Study design: Pre-treatment and pre-surgery lateral cephalograms for 86 patients who had combined orthodontic and orthognathic treatment were digitised using OPAL 2.1 [http://www.opalimage.co.uk]. To assess intra-observer reproducibility, 25 images were re-digitised one month later. Random and systematic error were assessed using the Dahlberg formula and a two-sample t-test, respectively. Differences in the proportions of cases where the maxillary (1100 +/- 60) or mandibular (900 +/- 60) incisors were fully decomensated were assessed using a Chi-square test (p<0.05). Mann-Whitney U tests were used to identify if there were any differences in the amount of net decompensation for maxillary and mandibular incisors between the Class II combined and Class III groups (p<0.05). Results: Random and systematic error were less than 0.5 degrees and p<0.05, respectively. A greater proportion of cases had decompensated mandibular incisors (80%) than maxillary incisors (62%) and this difference was statistically significant (p=0.029). The amount of maxillary incisor decompensation in the Class II and Class III groups did not statistically differ (p=0.45) whereas the mandibular incisors in the Class III group underwent statistically significantly greater decompensation (p=0.02). Conclusions: Mandibular incisors were decompensated for a greater proportion of cases than maxillary incisors in preparation for orthognathic surgery. There was no difference in the amount of maxillary incisor decompensation between Class II and Class III cases. There was a greater net decompensation for mandibular incisors in Class III cases when compared to Class II cases. Key words:Decompensation, orthognathic, pre-surgical orthodontics, surgical-orthodontic. PMID:25136421

  14. 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

  15. Myofilament calcium sensitization delays decompensated hypertrophy differently between the sexes following myocardial infarction

    PubMed Central

    Shioura, Krystyna M.; Farjah, Mariam; Geenen, David L.; Solaro, R. John

    2011-01-01

    Contractile dysfunction is common to many forms of cardiovascular disease. Approaches directed at enhancing cardiac contractility at the level of the myofilaments during heart failure (HF) may provide a means to improve overall cardiovascular function. We are interested in gender-based differences in cardiac function and the effect of sarcomere activation agents that increase contractility. Thus, we studied the effect of gender and time on integrated arterial-ventricular function (A-V relationship) following myocardial infarction (MI). In addition, transgenic mice that overexpress the slow skeletal troponin I isoform were used to determine the impact of increased myofilament Ca2+ sensitivity following MI. Based on pressure-volume (P-V) loop measurements, we used derived parameters of cardiovascular function to reveal the effects of sex, time, and increased myofilament Ca2+ sensitivity among groups of post-MI mice. Analysis of the A-V relationship revealed that the initial increase was similar between the sexes, but the vascular unloading of the heart served to delay the decompensated stage in females. Conversely, the vascular response at 6 and 10 wk post-MI in males contributed to the continuous decline in cardiovascular function. Increasing the myofilament Ca2+ sensitivity appeared to provide sufficient contractile support to improve contractile function in both male and female transgenic mice. However, the improved contractile function was more beneficial in males as the concurrent vascular response contributed to a delayed decompensated stage in female transgenic mice post-MI. This study represents a quantitative approach to integrating the vascular-ventricular relationship to provide meaningful and diagnostic value following MI. Consequently, the data provide a basis for understanding how the A-V relationship is coupled between males and females and the enhanced ability of the cardiovascular system to tolerate pathophysiological stresses associated with HF in

  16. Influence of bilevel positive airway pressure on autonomic tone in hospitalized patients with decompensated heart failure

    PubMed Central

    Lacerda, Diego; Costa, Dirceu; Reis, Michel; Gomes, Evelim Leal de F. Dantas; Costa, Ivan Peres; Borghi-Silva, Audrey; Marsico, Aline; Stirbulov, Roberto; Arena, Ross; Sampaio, Luciana Maria Malosá

    2016-01-01

    [Purpose] This study evaluated the effect of Bilevel Positive Airway (BiPAP) on the autonomic control of heart rate, assessed by heart rate variability (HRV), in patients hospitalized with decompensated heart failure. [Subjects and Methods] This prospective cross-sectional study included 20 subjects (age: 69±8 years, 12 male, left ventricular ejection fraction: 36 ±8%) diagnosed with heart failure who were admitted to a semi-intensive care unit with acute decompensation. Date was collected for HRV analysis during: 10 minutes spontaneous breathing in the resting supine position; 30 minutes breathing with BiPAP application (inspiratory pressure = 20 cmH2O and expiratory pressure = 10 cmH2O); and 10 minutes immediately after removal of BiPAP, during the return to spontaneous breathing. [Results] Significantly higher values for indices representative of increased parasympathetic activity were found in the time and frequency domains as well as in nonlinear Poincaré analysis during and after BiPAP in comparison to baseline. Linear HRV analysis: standard deviation of the average of all R-R intervals in milliseconds = 30.99±4.4 pre, 40.3±6.2 during, and 53.3±12.5 post BiPAP. Non-linear HRV analysis: standard deviations parallel in milliseconds = 8.31±4.3 pre, 12.9±5.8 during, and 22.8 ±6.3 post BiPAP. [Conclusion] The present findings demonstrate that BiPAP enhances vagal tone in patients with heart failure, which is beneficial for patients suffering from acute decompensation. PMID:26957719

  17. The role of attention in the tinnitus decompensation: reinforcement of a large-scale neural decompensation measure.

    PubMed

    Low, Yin Fen; Trenado, Carlos; Delb, Wolfgang; Corona-Strauss, Farah I; Strauss, Daniel J

    2007-01-01

    Large-scale neural correlates of the tinnitus decompensation have been identified by using wavelet phase stability criteria of single sweep sequences of auditory late responses (ALRs). The suggested measure provided an objective quantification of the tinnitus decompensation and allowed for a reliable discrimination between a group of compensated and decompensated tinnitus patients. By interpreting our results with an oscillatory tinnitus model, our synchronization stability measure of ALRs can be linked to the focus of attention on the tinnitus signal. In the following study, we examined in detail the correlates of this attentional mechanism in healthy subjects. The results support our previous findings of the phase synchronization stability measure that reflected neural correlates of the fixation of attention to the tinnitus signal. In this case, enabling the differentiation between the attended and unattended conditions. It is concluded that the wavelet phase synchronization stability of ALRs single sweeps can be used as objective tinnitus decompensation measure and can be interpreted in the framework of the Jastreboff tinnitus model and adaptive resonance theory. Our studies confirm that the synchronization stability in ALR sequences is linked to attention. This measure is not only able to serve as objective quantification of the tinnitus decompensation, but also can be applied in all online and real time neurofeedback therapeutic approach where a direct stimulus locked attention monitoring is compulsory as if it based on a single sweeps processing.

  18. 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

  19. Peritoneal ultrafiltration in patients with advanced decompensated heart failure.

    PubMed

    Iadarola, Gian Maria; Lusardi, Paola; La Milia, Vincenzo; Amici, Gianpaolo; Santarelli, Stefano; Virga, Giovambattista; Basile, Carlo; Bertoli, Silvio; Bonofiglio, Renzo; Del Rosso, Goffredo; Feriani, Mariano; Galli, Emilio; Gallieni, Maurizio; Gambaro, Giovanni; Sandrini, Massimo; Sisca, Sergio; Cancarini, Giovanni

    2013-01-01

    The aim of the Best Practice guidelines on peritoneal ultrafiltration (UF) in patients with treatment-resistant advanced decompensated heart failure (TR-AHDF) is to achieve a common approach to the management of decompensated heart failure in those situations in which all conventional treatment options have been unsuccessful, and to stimulate a closer cooperation between nephrologists and cardiologists. The standardization of the case series of different centers would allow a better definition of the results published in the literature, without which they are nothing more than anecdotes. TR-AHDF is characterized by the persistence of severe symptoms even when all possible pharmacological and surgical options have been exhausted. These patients are often treated with methods that allow extracorporeal UF - slow continuous ultrafiltration (SCUF) and continuous renal replacement therapy (CRRT) - which have to be performed in hospital facilities. Peritoneal ultrafiltration (PUF) can be considered a treatment option in patients with TR-AHDF when, despite the fact that all treatment options have been used, patients meet the following criteria: • stage D decompensated heart failure (ACC/AHA classification); • INTERMACS level 4 decompensated heart failure; • INTERMACS frequent flyer profile; • chronic renal failure (estimated glomerular filtration rate <50 ml/min per 1.73 m2: KDOQI classification stage 3 chronic kidney disease); • no obvious contraindications to peritoneal UF. PUF treatment modes are derived from the treatment regimens proposed by various authors to obtain systemic UF in patients with severe decompensated heart failure, using manual and automated incremental peritoneal dialysis involving various glucose concentrations in addition to the single icodextrin exchange. These guidelines also identify a minimum set of tests and procedures for the follow-up phase, to be supplemented, according to the center's resources and policy, with other tests that

  20. Predictors of fifty days in-hospital mortality in decompensated cirrhosis patients with spontaneous bacterial peritonitis

    PubMed Central

    Bal, Chinmaya Kumar; Daman, Ripu; Bhatia, Vikram

    2016-01-01

    AIM: To determine the predictors of 50 d in-hospital mortality in decompensated cirrhosis patients with spontaneous bacterial peritonitis (SBP). METHODS: Two hundred and eighteen patients admitted to an intensive care unit in a tertiary care hospital between June 2013 and June 2014 with the diagnosis of SBP (during hospitalization) and cirrhosis were retrospectively analysed. SBP was diagnosed by abdominal paracentesis in the presence of polymorphonuclear cell count ≥ 250 cells/mm3 in the peritoneal fluid. Student’s t test, multivariate logistic regression, cox proportional hazard ratio (HR), receiver operating characteristics (ROC) curves and Kaplan-Meier survival analysis were utilized for statistical analysis. Predictive abilities of several variables identified by multivariate analysis were compared using the area under ROC curve. P < 0.05 were considered statistical significant. RESULTS: The 50 d in-hospital mortality rate attributable to SBP is 43.11% (n = 94). Median survival duration for those who died was 9 d. In univariate analysis acute kidney injury (AKI), hepatic encephalopathy, septic shock, serum bilirubin, international normalized ratio, aspartate transaminase, and model for end-stage liver disease - sodium (MELD-Na) were significantly associated with in - hospital mortality in patients with SBP (P ≤ 0.001). Multivariate cox proportional regression analysis showed AKI (HR = 2.16, 95%CI: 1.36-3.42, P = 0.001) septic shock (HR = 1.73, 95%CI: 1.05-2.83, P = 0.029) MELD-Na (HR = 1.06, 95%CI: 1.02-1.09, P ≤ 0.001) was significantly associated with 50 d in-hospital mortality. The prognostic accuracy for AKI, MELD-Na and septic shock was 77%, 74% and 71% respectively associated with 50 d in-hospital mortality in SBP patients. CONCLUSION: AKI, MELD-Na and septic shock were predictors of 50 d in-hospital mortality in decompensated cirrhosis patients with SBP. PMID:27134704

  1. 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

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

    PubMed Central

    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. PMID:26834955

  3. Diagnosis and management of bacterial infections in decompensated cirrhosis

    PubMed Central

    Pleguezuelo, Maria; Benitez, Jose Manuel; Jurado, Juan; Montero, Jose Luis; De la Mata, Manuel

    2013-01-01

    Bacterial infections are one of the most frequent complications in cirrhosis and result in high mortality rates. Patients with cirrhosis have altered and impaired immunity, which favours bacterial translocation. Episodes of infections are more frequent in patients with decompensated cirrhosis than those with compensated liver disease. The most common and life-threatening infection in cirrhosis is spontaneous bacterial peritonitis followed by urinary tract infections, pneumonia, endocarditis and skin and soft-tissue infections. Patients with decompensated cirrhosis have increased risk of developing sepsis, multiple organ failure and death. Risk factors associated with the development of infections are severe liver failure, variceal bleeding, low ascitic protein level and prior episodes of spontaneous bacterial peritonitis (SBP). The prognosis of these patients is closely related to a prompt and accurate diagnosis. An appropriate treatment decreases the mortality rates. Preventive strategies are the mainstay of the management of these patients. Empirical antibiotics should be started immediately following the diagnosis of SBP and the first-line antibiotic treatment is third-generation cephalosporins. However, the efficacy of currently recommended empirical antibiotic therapy is very low in nosocomial infections including SBP, compared to community-acquired episodes. This may be associated with the emergence of infections caused by Enterococcus faecium and extended-spectrum β-lactamase-producing Enterobacteriaceae, which are resistant to the first line antimicrobial agents used for treatment. The emergence of resistant bacteria, underlines the need to restrict the use of prophylactic antibiotics to patients with the greatest risk of infections. Nosocomial infections should be treated with wide spectrum antibiotics. Further studies of early diagnosis, prevention and treatment are needed to improve the outcomes in patients with decompensated cirrhosis. PMID:23383362

  4. Precipitating factors leading to decompensation of chronic heart failure in the elderly patient in South-American community hospital

    PubMed Central

    Diaz, Alejandro; Ciocchini, Cleto; Esperatti, Mariano; Becerra, Alberto; Mainardi, Sabrina; Farah, Alejandro

    2011-01-01

    Background Exacerbations of heart failure appear frequently associated with precipitating factors not directly related to the evolution of cardiac disease. There still a paucity of data on the proportional distribution of precipitating factors specifically in elderly patients. The aim of this study was to examine prospectively the precipitating factors leading to hospitalization in elderly patients with heart failure in our community hospital. Methods We evaluate elderly patients who need admissions for decompensate heart failure. All patients were reviewed daily by the study investigators at the first 24 h and closely followed-up. Decompensation was defined as the worsening in clinical NYHA class associated with the need for an increase in medical treatment (at minimum intravenously diuretics). Results We included 102 patients (mean age 79 ± 12 years). Precipitating factors were identified in 88.5%. The decompensation was sudden in 35% of the cases. Noncompliance with diet was identified in 52% of the patients, lack of adherence to the prescribed medications amounted to 30%. Others precipitating factors were infections (29%), arrhythmias (25%), acute coronary ischemia (22%), and uncontrolled hypertension (15%), miscellaneous causes were detected in 18% of the cases (progression of renal disease 60%, anemia 30% and iatrogenic factors 10%). Concomitant cause was not recognizable in 11.5%. Conclusions Large proportion heart failure hospitalizations are associated with preventable precipitating factors. Knowledge of potential precipitating factors may help to optimize treatment and provide guidance for patients with heart failure. The presence of potential precipitating factors should be routinely evaluated in patients presenting chronic heart failure. PMID:22783279

  5. Managing patients with hepatitis‑B-related or hepatitis‑C-related decompensated cirrhosis.

    PubMed

    Fink, Scott A; Jacobson, Ira M

    2011-05-01

    Treatment of patients with hepatitis-B-related or hepatitis-C-related decompensated cirrhosis should focus on controlling the complications of cirrhosis, surveillance for hepatocellular carcinoma and, if applicable, preparation for orthotopic liver transplant. Interferon-based regimens for the treatment of hepatitis C have been somewhat successful in patients with cirrhosis, although treatment of patients with decompensated cirrhosis should be approached with caution. Given the potential for exacerbation of decompensation and poor tolerance of adverse effects, treatment should be reserved for those patients awaiting liver transplantation. Eradication of HCV before liver transplantation reduces the chances of recurrent hepatitis C infection after transplant. HBV can be treated with few adverse effects in patients with decompensated cirrhosis. This treatment is associated with improvement in decompensation in some patients. Hepatocellular carcinoma remains a significant risk in all patients with cirrhosis, and control of or eradication of HBV or HCV does not remove this risk. PMID:21695841

  6. The Role of Ultrafiltration in Patients with Decompensated Heart Failure

    PubMed Central

    Kamath, Sandeep A.

    2011-01-01

    Congestion, due in large part to hypervolemia, is the primary driver of heart failure (HF) admissions. Relief of congestion has been traditionally achieved through the use of loop diuretics, but there is increasing concern that these agents, particularly at high doses, may be deleterious in the inpatient setting. In addition, patients with HF and the cardiorenal syndrome (CRS) have diminished response to loop diuretics, making these agents less effective at relieving congestion. Ultrafiltration, a mechanical volume removal strategy, has demonstrated promise in achieving safe and effective volume removal in patients with cardiorenal syndrome and diuretic refractoriness. This paper outlines the rationale for ultrafiltration in CRS and the available evidence regarding its use in patients with HF. At present, the utility of ultrafiltration is restricted to selected populations, but a greater understanding of how this technology impacts HF and CRS may expand its use. PMID:21151532

  7. Dissociative detachment relates to psychotic symptoms and personality decompensation.

    PubMed

    Allen, J G; Coyne, L; Console, D A

    1997-01-01

    Previous studies have addressed the prominence of psychotic symptoms in conjunction with multiple personality disorder (now dissociative identity disorder). The present study examines the relation between psychotic symptoms and a more pervasive form of dissociative disturbance, namely dissociative detachment. Two hundred sixty-six women in inpatient treatment for severe trauma-related disorders completed the Dissociative Experiences Scale (DES), and 102 of these patients also completed the Millon Clinical Multiaxial Inventory (MCMI-III). A factor analysis of the DES yielded two dimensions of dissociative detachment: detachment from one's own actions and detachment from the self and the environment. Each of these DES dimensions relates strongly to the thought disorder and schizotypal personality disorder scales of the MCMI-III. We propose that severe dissociative detachment, by virtue of loosening the moorings in inner and outer reality, is conducive to psychotic symptoms and personality decompensation.

  8. 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

  9. Decompensated Liver Cirrhosis Presenting as a Spontaneous Left-Sided Bacterial Empyema.

    PubMed

    Chertoff, Jason; Nathoo, Sunina

    2016-01-01

    Decompensation of cirrhosis presents with ascites, encephalopathy, variceal bleeding, or spontaneous bacterial peritonitis. Infrequently, decompensation can result from spontaneous bacterial empyema. A 38-year-old man presented with fevers, chills, and dyspnea. Labs were significant for leukocytosis, transaminitis, and coagulopathy. Imaging showed liver cirrhosis with ascites and a left pleural effusion. Treatment of the effusion consisted of chest tube drainage and antibiotics. Spontaneous bacterial empyema was diagnosed after pleural fluid cultures were positive for Escherichia coli. Our case demonstrates that spontaneous bacterial empyemas can be left-sided, and the first sign of decompensation. PMID:26958567

  10. 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

  11. [Critically ill patients with decompensated liver cirrhosis - New aspects and intensive care management].

    PubMed

    Maschmeier, Miriam; Hüsing, Anna; Schmidt, Hartmut; Kabar, Iyad

    2015-10-01

    The prevalence of liver cirrhosis in the German population is about 1 %. Clinically, compensated liver cirrhosis should be distinguished from decompensated cirrhosis with poor prognosis. Decompensated cirrhosis is defined by the occurrence of complications and consequences of portal hypertension (such as ascites, variceal bleeding, hepatic encephalopathy and hepatorenal syndrome) and progressive liver failure. Optimizing the management of these patients in the intensive care unit could essentially improve their outcome. PMID:26445254

  12. Hospital Re-Admissions among Patients with Decompensated Cirrhosis

    PubMed Central

    Volk, Michael L.; Tocco, Rachel S.; Bazick, Jessica; Rakoski, Mina O.; Lok, Anna S.

    2012-01-01

    OBJECTIVES Early re-hospitalizations have been well characterized in many disease states, but not among patients with cirrhosis. The aims of this study were to identify the frequency, costs, predictors, and preventable causes of hospital re-admissions among patients with decompensated cirrhosis. METHODS Rates of re-admission were calculated for 402 patients discharged after one of the following complications of cirrhosis: ascites, spontaneous bacterial peritonitis, renal failure, hepatic encephalopathy or variceal hemorrhage. Costs of re-admissions were calculated using the hospital accounting system. Predictors of time to first re-admission were determined using Cox regression, and predictors of hospitalization rate/person-years using negative binomial regression. The independent association between re-admission rate and mortality was determined using Cox regression. Admissions within 30 days of discharge were assessed by two reviewers to determine if preventable. RESULTS 276 (69%) subjects had at least one non-elective re-admission, with a median time to first re-admission of 67 days. By one week after discharge 14% of subjects had been re-admitted, and 37% were re-admitted within one month. The mean costs for re-admissions within one week and between weeks 1–4 were $28,898 and %20,581, respectively. During a median follow-up of 203 days, the median number of re-admissions was 2 (range 0–40), with an overall rate of 3 hospitalizations/person-years. Patients with more frequent re-admissions had higher risk of subsequent mortality, despite adjustment for confounders including the Model for End-stage Liver Disease score. Predictors of time to first re-admission included MELD score, serum sodium, and number of medications on discharge; predictors of hospitalization rate included these variables as well as the number of cirrhosis complications and being on the transplant list at discharge. Among 165 re-admissions within 30 days, 22% were possibly preventable

  13. 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.

  14. Hagen-Poiseuille's law: The link between cirrhosis, liver stiffness, portal hypertension and hepatic decompensation.

    PubMed

    Lake-Bakaar, Gerond; Ahmed, Muneeb; Evenson, Amy; Bonder, Alan; Faintuch, Salomao; Sundaram, Vinay

    2015-01-27

    The onset of hepatic decompensation in cirrhosis heralds an accelerated downhill course with poor outcome. The sole predictor of this decompensation in cirrhosis is increased hepatic vein to portal vein gradient hepatic venous pressure gradient (HVPG). Surrogate markers of liver function or hepatic reserve appear to be less relevant. The hepatic sinusoids become less elastic and more rigid as liver fibrosis and cirrhosis progress. We propose that the Hagen-Poiseuille's law, which applies to rigid, but not elastic vessels, determines the pressure-flow characteristics in the sinusoids. In the rigid cirrhotic liver, HVPG rises dramatically with any change in net surface area or radius, r(4) of the vasculature that follows surgical resection. This review relates liver stiffness to the risk of decompensation in patients with cirrhosis. The liver has a unique dual blood supply comprising a low pressure portal vein and high pressure hepatic artery. We compare the complexity of autoregulation in the normal elastic liver with that in the rigid cirrhotic liver. Therapeutic modalities to reduce portal pressure may reduce the risk of hepatic decompensation and improve outcomes in cirrhosis.

  15. Hagen-Poiseuille’s law: The link between cirrhosis, liver stiffness, portal hypertension and hepatic decompensation

    PubMed Central

    Lake-Bakaar, Gerond; Ahmed, Muneeb; Evenson, Amy; Bonder, Alan; Faintuch, Salomao; Sundaram, Vinay

    2015-01-01

    The onset of hepatic decompensation in cirrhosis heralds an accelerated downhill course with poor outcome. The sole predictor of this decompensation in cirrhosis is increased hepatic vein to portal vein gradient hepatic venous pressure gradient (HVPG). Surrogate markers of liver function or hepatic reserve appear to be less relevant. The hepatic sinusoids become less elastic and more rigid as liver fibrosis and cirrhosis progress. We propose that the Hagen-Poiseuille’s law, which applies to rigid, but not elastic vessels, determines the pressure-flow characteristics in the sinusoids. In the rigid cirrhotic liver, HVPG rises dramatically with any change in net surface area or radius, r4 of the vasculature that follows surgical resection. This review relates liver stiffness to the risk of decompensation in patients with cirrhosis. The liver has a unique dual blood supply comprising a low pressure portal vein and high pressure hepatic artery. We compare the complexity of autoregulation in the normal elastic liver with that in the rigid cirrhotic liver. Therapeutic modalities to reduce portal pressure may reduce the risk of hepatic decompensation and improve outcomes in cirrhosis. PMID:25624993

  16. 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.

  17. Autonomic Predictors of Hospitalization Due to Heart Failure Decompensation in Patients with Left Ventricular Systolic Dysfunction

    PubMed Central

    Suchecka, Justyna; Niemirycz-Makurat, Agnieszka; Rozwadowska, Katarzyna

    2016-01-01

    Introduction Autonomic nervous system balance can be significantly deteriorated during heart failure exacerbation. However, it is still unknown whether these changes are only the consequence of heart failure decompensation or can also predict development thereof. Objectives were to verify if simple, non-invasive autonomic parameters, such as baroreflex sensitivity and short-term heart rate variability can provide independent of other well-known clinical parameters information on the risk of heart failure decompensation in patients with left ventricular systolic dysfunction. Methods In 142 stable patients with left ventricular ejection fraction ≤ 40%, baroreflex sensitivity and short-term heart rate variability, as well as other well-known clinical parameters, were analyzed. During 23 ± 9 months of follow-up 19 patients were hospitalized due to the heart failure decompensation (EVENT). Results Pre-specified cut-off values of baroreflex sensitivity (≤2.4 ms/mmHg) and low frequency power index of heart rate variability (≤19 ms2) were significantly associated with the EVENTs (hazard ratio 4.43, 95% confidence interval [CI] 1.35–14.54 and 5.41, 95% CI 1.87–15.65 respectively). EVENTs were also associated with other parameters, such as left ventricular ejection fraction, NYHA class, diuretic use, renal function, brain natriuretic peptide and hemoglobin level, left atrial size, left and right ventricular heart failure signs. After adjusting baroreflex sensitivity and low frequency power index for each of the abovementioned parameters, autonomic parameters were still significant predictors of hospitalization due to the heart failure decompensation. Conclusion Simple, noninvasive autonomic indices can be helpful in identifying individuals with increased risk of hospitalization due to the heart failure decompensation among clinically stable patients with left ventricular systolic dysfunction, even when adjusted for other well-known clinical parameters. PMID

  18. Cell-Free and Concentrated Ascites Reinfusion Therapy for Decompensated Liver Cirrhosis.

    PubMed

    Kozaki, Koichi; IInuma, Masahiro; Takagi, Tomoyuki; Fukuda, Takanori; Sanpei, Takaya; Terunuma, Yusuke; Yatabe, Yoshiharu; Akano, Kazuhiro

    2016-08-01

    Cell-free and concentrated ascites reinfusion therapy (CART) is expected to improve symptoms associated with refractory ascites of the decompensated liver cirrhosis patients. The aim of this study was to evaluate the safety and efficacy of the CART system performed on the decompensated liver cirrhosis patients. In this retrospective observational study, we evaluated 24 CART processes performed on 11 patients with decompensated liver cirrhosis. We evaluated the effectiveness and adverse events during CART procedures. The amounts of collected and concentrated ascites were 4491.7 ± 2222.8 mL (mean ± SD), respectively, and the concentration ratio was 22.4 ± 15.3 times, respectively. The amount of collected protein in ascites was 2.3 ± 0.5 g/dL, and concentration ratio of protein was 8.2 ± 9.4 times. Serum protein level was not significantly different between before and after CART sessions. Thus, CART allowed for the reduction of doses of albumin preparations (Alb) to be administered. CART has been reported to cause two adverse reactions: elevation of body temperature and decrease in blood pressure. In our study, decreased blood pressure was not observed even in patients with > 5 L of ascites drained. Although a transient elevation in body temperature was seen in only one patient, this febrile patient immediately returned to normal body temperature with the use of NSAIDs. In patients with refractory ascites of decompensated liver cirrhosis in whom complete cure cannot be expected, CART improves their QOL and, in terms of medical economy, allows for the reduction of doses of Alb. CART can be effectively applied as a palliative procedure for refractory ascites of decompensated liver cirrhosis patients. PMID:27523078

  19. Liver Enzymes and Uric acid in Acute Heart Failure

    PubMed Central

    Vakilian, Farveh; Rafighdoost, Abbas Ali; Rafighdoost, Amir Hossein; Amin, Ahmad; Salehi, Maryam

    2015-01-01

    Background: Acute heart failure (AHF) is defined as the new onset or recurrence of gradual or rapidly worsening signs and symptoms of heart failure, requiring urgent or emergent therapy. Objectives: This study attempts to assess the association of liver function tests (LFT) and uric acid level with in hospital outcome and echocardiography parameters, in patients with acute decompensated heart failure. Patients and Methods: A total of 100 patients (aged 16 - 90 years, 60% men) admitted with AHF were enrolled. LFTs and uric acid levels were assessed on first day and before discharge, and patients were followed for 3 months. Results: In-hospital outcomes were considered. Mean Left Ventricular Ejection Fraction (LVEF) was 35% (20 - 45%). Mean Uric acid level was 8.4 mg/dL, significantly higher than chronic HF and normal groups (P < 0.02). Elevated liver enzymes were seen in 52% patients, mostly (87%) in transaminases. Liver enzymes were decreased in 85% patients before discharge. LFT and uric acid levels were inversely and significantly correlated with LVEF on echocardiography (P = 0.02), but not with diastolic parameters. Although there was no significant correlation between uric acid level and in-hospital mortality, risk of intubation and rehospitalization in 3 months, enzyme levels increased in these groups. Increased aspartate transaminase (AST level) was associated with inotrope infusion in AHF patients (42 vs. 82 mg/dL, P = 0.03). Conclusions: Abnormal transaminases and uric acid levels are seen in AHF patients. Increased AST levels may be a predictor of the need for inotrope during hospital course in these patients. PMID:26528447

  20. Acute Management of Propionic Acidemia

    PubMed Central

    Chapman, Kimberly A; Gropman, Andrea; MacLeod, Erin; Stagni, Kathy; Summar, Marshall L.; Ueda, Keiko; Mew, Nicholas Ah; Franks, Jill; Island, Eddie; Matern, Dietrich; Pena, Loren; Smith, Brittany; Sutton, V. Reid; Urv, Tiina; Venditti, Charles; Chakrapani, Anupam

    2014-01-01

    Propionic Acidemia or aciduria is an intoxication-type disorder of organic metabolism. Patients deteriorate in times of increased metabolic demand and subsequent catabolism. Metabolic decompensation can manifest with lethargy, vomiting, coma and death if not appropriately treated. On January 28-30, 2011 in Washington, D.C., Children's National Medical Center hosted a group of clinicians, scientists and parental group representatives to design recommendations for acute management of individuals with Propionic Acidemia. Although many of the recommendations are geared towards the previously undiagnosed neonate, the recommendations for a severely metabolically decompensated individual are applicable to any known patient as well. Initial management is critical for prevention of morbidity and mortality. The following manuscript provides recommendations for initial treatment and evaluation, a discussion of issues concerning transport to a metabolic center (if patient presents to a non-metabolic center), acceleration of management and preparation for discharge. PMID:22000903

  1. Predictors of Acute Hemodynamic Decompensation in Early Sepsis: An Observational Study

    PubMed Central

    Lee, Young Im; Smith, Robert L.; Gartshteyn, Yevgeniya; Kwon, Sophia; Caraher, Erin J.; Nolan, Anna

    2016-01-01

    Background The study of sepsis is hindered by its heterogeneous time course and evolution. A subgroup of patients with severe sepsis develops shock soon after the initiation of treatment while others present hypotensive. We sought to determine the incidence of hypotension after the initiation of treatment for sepsis, and characterize their clinical features and course. Methods A retrospective review of electronic medical record of all septic patients (n = 542) that met the definition of septic shock within 24 hours of admission (2011 - 2012) at an urban Veteran Affairs Hospital was performed. Subjects either had 1) initial normotension (INT) with hypotension developing within 24 hours or 2) initial hypotension (IH). Logistic regression was used to model associated factors of INT/IH. Results INT occurred in 62 patients (11%) with average initial blood pressure of 120/71 mm Hg and developed hypotension to 79/48 mm Hg. IH was identified in 52 patients (10%) with average presenting blood pressure of 81/46 mm Hg. INT showed evidence of increased sympathetic tone with significantly higher heart rate, blood pressure and temperature. INT patients were younger, more frequently on alpha-blockers, and more likely septic from pneumonia compared to IH patients. INT and IH patients had similar timing of antibiotic initiation, amount of 24-hour fluid resuscitation, vasopressor use, organ dysfunction and mortality at 28 days. Using alpha-blockers, being Caucasian, and having higher temperatures were independent predictors of INT. Conclusion INT is a distinctive presentation of septic shock characterized by rapid deterioration during early treatment. By further studying this subgroup, mediators of septic shock may be identified that clarify pathophysiology and provide timely targeted treatment. PMID:27429677

  2. MELD Score Kinetics in Decompensated HIV+/HCV+ Patients: A Useful Prognostic Tool (ANRS HC EP 25 PRETHEVIC Cohort Study).

    PubMed

    Gelu-Simeon, Moana; Bayan, Tatiana; Ostos, Maria; Boufassa, Faroudy; Teicher, Elina; Steyaert, Jean-Marc; Bertucci, Inga; Anty, Rodolphe; Pageaux, Georges-Philippe; Meyer, Laurence; Duclos-Vallée, Jean-Charles

    2015-07-01

    To assess prognostic factors for survival and describe Model for End-Stage liver disease (MELD) dynamics in human immunodeficiency virus+/hepatitis C virus+ (HIV+/HCV+) patients after an initial episode of hepatic decompensation.An HIV+/HCV+ cohort of patients experiencing an initial decompensation episode within the year preceding enrollment were followed prospectively. Clinical and biological data were collected every 3 months. Predictors for survival were identified using Kaplan-Meier curves and Cox models. A 2-slope-mixed linear model was used to estimate MELD score changes as a function of survival.Sixty seven patients were included in 32 centers between 2009 and 2012 (72% male; median age: 48 years [interquartile ratio (IQR):45-52], median follow-up: 22.4 months [range: 0.5-65.3]). Overall survival rates were 86%, 78%, and 59% at 6, 12, and 24 months, respectively. Under multivariate analysis, the MELD score at initial decompensation was predictive of survival, adjusted for age, type of decompensation, baseline CD4 counts, and further decompensation during follow-up as a time-dependent variable. The adjusted hazard ratio of death was 1.32 for a score 3 points higher (95% CI: [1.06-1.63], P = 0.012). MELD score kinetics within the 6 months after initial decompensation differed significantly between non-deceased and deceased patients, with a decreased (-0.49/month; P = 0.016), versus a flat (+0.06/month, P = 0.753) mean change in score.MELD is an effective tool to predict survival in HIV+/HCV+ patients with decompensated cirrhosis. A non-decreasing MELD score within 6 months following this initial decompensation episode may benefit from privileged access to liver transplantation in this poor prognosis population. PMID:26222860

  3. Evaluation of a compact tinnitus therapy by electrophysiological tinnitus decompensation measures.

    PubMed

    Low, Yin Fen; Argstatter, Heike; Bolay, Hans Volker; Strauss, Daniel J

    2008-01-01

    Large-scale neural correlates of the tinnitus decompensation have been identified by using wavelet phase stability criteria of single sweep sequences of auditory late responses (ALRs). Our previous work showed that the synchronization stability in ALR sequences might be used for objective quantification of the tinnitus decompensation and attention which link to Jastreboff tinnitus model. In this study, we intend to provide an objective evaluation for quantifying the effect of music therapy in tinnitus patients. We examined neural correlates of the attentional mechanism in single sweep sequences of ALRs in chronic tinnitus patients who underwent compact therapy course by using the maximum entropy auditory paradigm. Results by our measure showed that the extent of differentiation between attended and unattended conditions improved significantly after the therapy. It is concluded that the wavelet phase synchronization stability of ALRs single sweeps can be used for the objective evaluation of tinnitus therapies, in this case the compact tinnitus music therapy. PMID:19163872

  4. 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.

  5. Entecavir for Patients with Hepatitis B Decompensated Cirrhosis in China: a meta-analysis

    NASA Astrophysics Data System (ADS)

    Wang, F. Y.; Li, B.; Li, Y.; Liu, H.; Qu, W. D.; Xu, H. W.; Qi, J. N.; Qin, C. Y.

    2016-09-01

    Evidence about the clinical effects of entecavir (ETV) for patients with hepatitis B decompensated cirrhosis remain controversial. Therefore, we perform this meta-analysis to assess the treatment outcomes of ETV in participants with hepatitis B decompensated cirrhosis. Relevant studies were identified by searching databases until the March 2016. A random-effects model was used to estimate summary relative risks (RRs) and 95% confidence intervals (CIs). GRADEprofiler3.6 was used to evaluate the quality of the evidence. A total of 26 studies (involving 2040 patients) were included. The quality of the evidence was classified from very low to high by the GRADED approach for all included RCTs. Meta-analysis showed that patients were more likely to experience HBV-DNA loss (RR:1.85, 95%CIs: 1.41 to 2.43, P < 0.0001 at 48 weeks), have normalized alanine aminotransferase levels (ALT) (P = 0.003 at 24 weeks, P = 0.02 at 48 weeks), and have a low mortality rate at 24 weeks (P = 0.003) when treated with ETV. There was no significant different between ETV and the control groups at the total mortality (P = 0.06) and HBeAg seroconversion (P = 0.14). In conclusion, ETV could be the first line therapy for patients with HBV related decompensated cirrhosis, because ETV could reduce the early mortality and move HBV DNA load down.

  6. Entecavir for Patients with Hepatitis B Decompensated Cirrhosis in China: a meta-analysis

    PubMed Central

    Wang, F.Y.; Li, B.; Li, Y.; Liu, H.; Qu, W.D.; Xu, H.W.; Qi, J.N.; Qin, C.Y.

    2016-01-01

    Evidence about the clinical effects of entecavir (ETV) for patients with hepatitis B decompensated cirrhosis remain controversial. Therefore, we perform this meta-analysis to assess the treatment outcomes of ETV in participants with hepatitis B decompensated cirrhosis. Relevant studies were identified by searching databases until the March 2016. A random-effects model was used to estimate summary relative risks (RRs) and 95% confidence intervals (CIs). GRADEprofiler3.6 was used to evaluate the quality of the evidence. A total of 26 studies (involving 2040 patients) were included. The quality of the evidence was classified from very low to high by the GRADED approach for all included RCTs. Meta-analysis showed that patients were more likely to experience HBV-DNA loss (RR:1.85, 95%CIs: 1.41 to 2.43, P < 0.0001 at 48 weeks), have normalized alanine aminotransferase levels (ALT) (P = 0.003 at 24 weeks, P = 0.02 at 48 weeks), and have a low mortality rate at 24 weeks (P = 0.003) when treated with ETV. There was no significant different between ETV and the control groups at the total mortality (P = 0.06) and HBeAg seroconversion (P = 0.14). In conclusion, ETV could be the first line therapy for patients with HBV related decompensated cirrhosis, because ETV could reduce the early mortality and move HBV DNA load down. PMID:27601086

  7. Entecavir for Patients with Hepatitis B Decompensated Cirrhosis in China: a meta-analysis.

    PubMed

    Wang, F Y; Li, B; Li, Y; Liu, H; Qu, W D; Xu, H W; Qi, J N; Qin, C Y

    2016-01-01

    Evidence about the clinical effects of entecavir (ETV) for patients with hepatitis B decompensated cirrhosis remain controversial. Therefore, we perform this meta-analysis to assess the treatment outcomes of ETV in participants with hepatitis B decompensated cirrhosis. Relevant studies were identified by searching databases until the March 2016. A random-effects model was used to estimate summary relative risks (RRs) and 95% confidence intervals (CIs). GRADEprofiler3.6 was used to evaluate the quality of the evidence. A total of 26 studies (involving 2040 patients) were included. The quality of the evidence was classified from very low to high by the GRADED approach for all included RCTs. Meta-analysis showed that patients were more likely to experience HBV-DNA loss (RR:1.85, 95%CIs: 1.41 to 2.43, P < 0.0001 at 48 weeks), have normalized alanine aminotransferase levels (ALT) (P = 0.003 at 24 weeks, P = 0.02 at 48 weeks), and have a low mortality rate at 24 weeks (P = 0.003) when treated with ETV. There was no significant different between ETV and the control groups at the total mortality (P = 0.06) and HBeAg seroconversion (P = 0.14). In conclusion, ETV could be the first line therapy for patients with HBV related decompensated cirrhosis, because ETV could reduce the early mortality and move HBV DNA load down. PMID:27601086

  8. Advanced HF anti-jam network architecture

    NASA Astrophysics Data System (ADS)

    Jackson, E. M.; Horner, Robert W.; Cai, Khiem V.

    The Hughes HF2000 system was developed using a flexible architecture which utilizes a wideband RF front-end and extensive digital signal processing. The HF2000 antijamming (AJ) mode was field tested via an HF skywave path between Fullerton, CA and Carlsbad, CA (about 100 miles), and it was shown that reliable fast frequency-hopping data transmission is feasible at 2400 b/s without adaptive equalization. The necessary requirements of an HF communication network are discussed, and how the HF2000 AJ mode can be used to support those requirements is shown. The Hughes HF2000 AJ mode system architecture is presented.

  9. 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

  10. [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.

  11. Entecavir: a review of its use in the treatment of chronic hepatitis B in patients with decompensated liver disease.

    PubMed

    Keating, Gillian M

    2011-12-24

    The oral deoxyguanosine nucleoside analogue entecavir (Baraclude®) has potent activity against hepatitis B virus (HBV) and a high genetic barrier to resistance. This article reviews the clinical efficacy and tolerability of entecavir in the treatment of chronic hepatitis B in patients with decompensated liver disease, as well as summarizing its pharmacological properties. Entecavir 1 mg/day was more effective than adefovir dipivoxil 10 mg/day in the treatment of patients with chronic hepatitis B and decompensated liver disease, according to the results of a randomized, open-label, multicentre trial. Patients were either nucleos(t)ide naive or lamivudine experienced. The reduction from baseline in HBV DNA levels at week 24 (primary endpoint) was significantly greater with entecavir than with adefovir dipivoxil. The proportion of patients with HBV DNA levels of <300 copies/mL was also significantly greater with entecavir than with adefovir dipivoxil at weeks 24, 48 and 96, as was the proportion of patients with ALT normalization. Entecavir 0.5 or 1 mg/day, tenofovir disoproxil fumarate 300 mg/day and a fixed-dose combination of emtricitabine/tenofovir disoproxil fumarate 200 mg/300 mg per day were effective in the treatment of chronic hepatitis B in patients with decompensated liver disease, according to the 48-week analysis of a randomized, double-blind, multicentre trial, primarily designed to examine tolerability endpoints. In this trial, over one-third of patients had received previous therapy with lamivudine for ≥6 months. The efficacy of entecavir in treatment-naive patients with HBV-related decompensated cirrhosis did not significantly differ from that seen in patients with chronic hepatitis B or compensated cirrhosis (compensated group), according to the results of a prospective, nonrandomized study. After 6 or 12 months of entecavir treatment, there were no significant differences between the decompensated and compensated groups in virological

  12. [Dynamics of blood gases and acid-base balance in patients with carbon monoxide acute poisoning].

    PubMed

    Polozova, E V; Shilov, V V; Bogachova, A S; Davydova, E V

    2015-01-01

    Evaluation of blood gases and acid-base balance covered patients with carbon monoxide acute poisoning, in accordance with inhalation trauma presence. Evidence is that thermochemical injury of respiratory tract induced severe acid-base dysbalance remaining decompensated for a long time despite the treatment.

  13. 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. PMID:27657872

  14. 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.

  15. [Cerebral hemodynamic disorders in patients with chronic decompensated respiratory insufficiency. Physiopathogenetic considerations].

    PubMed

    Ionescu, M

    1978-01-01

    The present paper reports on 12 patients (8 males, 4 females) suffering from chronic decompensated respiratory failure, who presented concomitant transient haemodynamic disturbances in the carotid and vertebrobasilary systems, manifested by hemisphere or brain stem symptoms. Owing to the adaptive capacity of these patients there exists a certain tolerance threshold to hypercapnic hypoxemia, but following accentuated or rapid aggravation of acid-base hypercapnic hypoxemia, the biological balance is abruptly perturbed leading to cerebral haemodynamic disturbances. The pathophysiological mechanism of production appears to be the accumulation of acid ions caused by pH acidification of the cerebrospinal fluid. Increase in the cerebral arterial output with decrease in the rate of circulation and vascular resistance take place especially in the vessels with atheromatous or hyaline lesions. Under conditions of severe acidosic hypercapnic hypoxemia this, nevertheless, insures a minimum of 10--20% oxygen required by the metabolism of the nerve cell, sufficient for maintaining the structure of the cell (vita minima). These vasculometabolic mechanisms explain why with improvement of haematosis, following remission of the decompensated disease and fall in acidotic hypercapnic hypoxemia values, the cerebral haemodynamic disturbances also show a more or less evident remission because the nerve cells having maintained their structure are able to take up their function again.

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

    PubMed Central

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

    2016-01-01

    Abstract 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 × 109/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. PMID:27015182

  17. Rotenone-induced energy stress decompensated in ventral mesocerebrum is associated with Parkinsonism progression in rats

    PubMed Central

    Bai, Qunhua; He, Junlin; Tang, Yong; Wang, Shibo; Qiu, Jingfu; Wang, Yang; Yu, Chao

    2016-01-01

    Parkinson's disease (PD) is the second most common neurodegenerative disorder, which is characterized by the hallmark feature of loss of dopaminergic neurons in the substantia nigra. Energy metabolic disorder is associated with the pathogenesis of PD; however, the development of this disorder is yet to be elucidated. PD-like characteristics have been demonstrated in a rotenone rat model. In the present study, energy metabolism status was investigated in a rat model following intraperitoneal treatment with 1.0 mg/kg rotenone every 48 h. The behavior and tyrosine hydroxylase-positive levels in the substantia nigra of rats that were treated with rotenone for 24 weeks demonstrated that these rats developed more severe parkinsonism, as compared with that were treated for 16 weeks. Detection of ATP, lactic acid, NADH dehydrogenase 1 mRNA and lactate dehydrogenase B mRNA levels in the ventral mesocerebrum (VM) and skeletal muscle (SM) of the rats that had been treated with rotenone for 16 and 24 weeks demonstrated that the energy stress induced by rotenone progressed in both VM and SM. Notably, the energy stress detected in VM was more severe, and this energy stress was decompensated in the VM of rats that had been treated with rotenone for 24 weeks. The progression of energy stress and the incidence of energy decompensation in VM may be important for the improvement of PD pathology. PMID:27446321

  18. 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.

  19. 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.

  20. [The choice of optimal operative intervention in patients, suffering an acute tumoral impassability of large intestine].

    PubMed

    Ioffe, I V; Alekseev, A V; Pepenin, A V; Zhadanov, V I; Lisovoĭ, R V

    2012-03-01

    The results of treatment of 101 patients, suffering an acute ileus (AI), caused by colonic cancer, were presented. The operation was performed in 88 patients for AI in subcompensated and decompensated stages. Right-sided hemicolectomy with ileotransversoanastomosis formation was done for right-sided localization of the tumor in a subcompensated stage. The outloading end colostomy was done after tumoral excision and ileotransversoanastomosis formation accomplishment in patients, suffering AI in a decompensated stage with purulent peritonitis. Obstructive large-bowel resection was performed for left-sided colonic cancer with AI in a decompensated stage, and for subcompensated stage--a left-sided hemicolectomy with Y-type anastomosis was done. Postoperative complications rate have constituted 27.3% and lethality--12.5%.

  1. 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

  2. Crescendo in Depolarization and Repolarization Heterogeneity Heralds Development of Ventricular Tachycardia in Hospitalized Patients with Decompensated Heart Failure

    PubMed Central

    Nearing, Bruce D.; Wellenius, Gregory A.; Mittleman, Murray A.; Josephson, Mark E.; Burger, Andrew J.; Verrier, Richard L.

    2012-01-01

    Background A critical need exists for reliable warning markers of in-hospital life-threatening arrhythmias. We employed a new quantitative method to track interlead heterogeneity of depolarization and repolarization to detect premonitory changes prior to ventricular tachycardia (VT) in hospitalized patients with acute decompensated heart failure. Methods and Results Ambulatory ECGs (leads V1, V5, and aVF) recorded before initiation of drug therapy from patients enrolled in the Prospective Randomized Evaluation of Cardiac Ectopy with Dobutamine or Nesiritide Therapy (PRECEDENT) trial were analyzed. R-wave and T-wave heterogeneity (RWH, TWH) were assessed by second central moment analysis and T-wave alternans (TWA) by Modified Moving Average analysis. Patients (N=44) studied included those (N = 22) with episodes of VT (≥4 beats at heart rates >100 beats/min) following ≥120 minutes of stable sinus rhythm and age- and sex-matched patients (N=22) without VT. TWA increased from 18.6±2.1μV (baseline, mean ± SEM) to 27.9±4.6μV in lead V5 at 15–30 minutes prior to VT (p<0.05) and remained elevated until the arrhythmia occurred. TWA results in V1 and aVF were similar. RWH and TWH were elevated from 164.1±33.1μV and 134.5±20.6μV (baseline) to 299.8±54.5μV and 239.2±37.0μV at 30–45 minutes prior to VT (p<0.05), respectively, preceding the crescendo in TWA by 15 minutes. Matched patients without VT did not display elevated RWH (185.5±29.4μV) or TWH (157.1±27.2μV) during the 24–hour period. Conclusions This is the first clinical demonstration of the potential utility of tracking depolarization and repolarization heterogeneity to detect crescendos in electrical instability that could forewarn of impending nonsustained ventricular tachycardia. Clinical Trial Registration http://clinicaltrials.gov; NCT00270400. PMID:22157521

  3. The Relationship between Renal Dysfunction and Abnormalities of the Immune System in Patients with Decompensated Cirrhosis.

    PubMed

    Kakazu, Eiji; Kondo, Yasuteru; Shimosegawa, Tooru

    2012-01-01

    In patients with advanced cirrhosis, not only hepatocellular carcinoma but also bacterial infections, such as spontaneous bacterial peritonitis (SBP) or pneumonia, are frequent clinical complications in such immune-compromised patients. These pathologies often progress to renal dysfunction, especially hepatorenal syndrome (HRS). The central pathology of HRS is splanchnic arterial vasodilation and hyperpermeability followed by bacterial translocation (BT). BT induces a severe inflammatory response in the peritoneal lymphoid tissue, with the activation of the immune systems and the long-lasting production of vasoactive mediators that can impair the circulatory function and cause renal failure. Recent studies report that the plasma amino acid imbalance appeared to be related to an abnormality of the immune system in patients with decompensated cirrhosis. This paper can provide a new approach for future studies of the pathology in cirrhotic patients with renal dysfunction. PMID:23326675

  4. The Relationship between Renal Dysfunction and Abnormalities of the Immune System in Patients with Decompensated Cirrhosis

    PubMed Central

    Kakazu, Eiji; Kondo, Yasuteru; Shimosegawa, Tooru

    2012-01-01

    In patients with advanced cirrhosis, not only hepatocellular carcinoma but also bacterial infections, such as spontaneous bacterial peritonitis (SBP) or pneumonia, are frequent clinical complications in such immune-compromised patients. These pathologies often progress to renal dysfunction, especially hepatorenal syndrome (HRS). The central pathology of HRS is splanchnic arterial vasodilation and hyperpermeability followed by bacterial translocation (BT). BT induces a severe inflammatory response in the peritoneal lymphoid tissue, with the activation of the immune systems and the long-lasting production of vasoactive mediators that can impair the circulatory function and cause renal failure. Recent studies report that the plasma amino acid imbalance appeared to be related to an abnormality of the immune system in patients with decompensated cirrhosis. This paper can provide a new approach for future studies of the pathology in cirrhotic patients with renal dysfunction. PMID:23326675

  5. 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. PMID:27056646

  6. 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

  7. 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.

  8. 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.

  9. Study of factors for unsuitability of DSAEK in cases of corneal decompensation following cataract surgery.

    PubMed

    Sharma, Namrata; Sachdev, Ritika; Pandey, Ravindra M; Titiyal, Jeewan S; Sinha, Rajesh; Tandon, Radhika; Vajpayee, Rasik B

    2012-08-01

    To evaluate suitability of Descemet's stripping automated endothelial keratoplasty (DSAEK) in cases of corneal decompensation following cataract surgery. In this cross-sectional case series, 90 eyes of 90 patients were evaluated at a tertiary eye care centre. Cases with central corneal scarring or vascularisation, complicated aphakia with significant iris tissue defects and extensive synechaie or posterior segment pathology precluding visual recovery were classified as unsuitable for DSAEK. Of 90 eyes, 42 (46.67%) were unsuitable for DSAEK. Multivariate logistic regression analysis, revealed that patients presenting more than a year after cataract surgery had 7.5-fold odds of being unsuitable for DSAEK as compared with those who presented earlier(OR 7.5; CI 2.0-29.1). Patients with BCVA poorer than 0.06 at initial presentation had 5.0 times odds of being unsuitable for DSAEK (OR 5.0; CI 1.0-24.2). Patients who had prior non-phacoemulsification cataract surgery were 5.5 times less likely to be candidates for DSAEK as compared to those who had prior phacoemulsification (OR 5.5; CI 1.5-19.9) and those with anterior chamber IOL or aphakia were 5.0 times less likely suitable for DSAEK, in contrast to posterior chamber intraocular lenses (OR 5.0; CI 1.3-18.7). The type of cataract surgery, time to presentation and initial visual acuity play a role in determining the suitability of performing DSAEK in patients with corneal decompensation after cataract surgery.

  10. Exercise training improves renal excretory responses to acute volume expansion in rats with heart failure.

    PubMed

    Zheng, Hong; Li, Yi-Fan; Zucker, Irving H; Patel, Kaushik P

    2006-12-01

    Experiments were performed to test the postulate that exercise training (ExT) improves the blunted renal excretory response to acute volume expansion (VE), in part, by normalizing the neural component of the volume reflex typically observed in chronic heart failure (HF). Diuretic and natriuretic responses to acute VE were examined in sedentary and ExT groups of rats with either HF or sham-operated controls. Experiments were performed in anesthetized (Inactin) rats 6 wk after coronary ligation surgery. Histological data indicated that there was a 34.9 +/- 3.0% outer and 42.5 +/- 3.2% inner infarct of the myocardium in the HF group. Sham rats had no observable damage to the myocardium. In sedentary rats with HF, VE produced a blunted diuresis (46% of sham) and natriuresis (35% of sham) compared with sham-operated control rats. However, acute VE-induced diuresis and natriuresis in ExT rats with HF were comparable to sham rats and significantly higher than sedentary HF rats. Renal denervation abolished the salutary effects of ExT on renal excretory response to acute VE in HF. Since glomerular filtration rates were not significantly different between the groups, renal hemodynamic changes may not account for the blunted renal responses in rats with HF. Additional experiments confirmed that renal sympathetic nerve activity responses to acute VE were blunted in sedentary HF rats; however, ExT normalized the renal sympathoinhibition in HF rats. These results confirm an impairment of neurally mediated excretory responses to acute VE in rats with HF. ExT restored the blunted excretory responses as well as the renal sympathoinhibitory response to acute VE in HF rats. Thus the beneficial effects of ExT on cardiovascular regulation in HF may be partly due to improvement of the neural component of volume reflex.

  11. 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. PMID:26949146

  12. The pathophysiology of hypertensive acute heart failure.

    PubMed

    Viau, David M; Sala-Mercado, Javier A; Spranger, Marty D; O'Leary, Donal S; Levy, Phillip D

    2015-12-01

    While acute heart failure (AHF) is often regarded as a single disorder, an evolving understanding recognises the existence of multiple phenotypes with varied pathophysiological alterations. Herein we discuss hypertensive AHF and provide insight into a mechanism where acute fluid redistribution is caused by a disturbance in the ventricular-vascular coupling relationship. In this relationship, acute alterations in vascular elasticity, vasoconstriction and reflected pulse waves lead to increases in cardiac work and contribute to decompensated LV function with associated subendocardial ischaemia and end-organ damage. Chronic predisposing factors (neurohormonal activity, nitric oxide insensitivity, arterial stiffening) and physiological stressors (sympathetic surge, volume overload, physical exertion) that are causally linked to acute symptom onset are discussed. Lastly, we review treatment options including both nitrovasodilators and promising novel therapeutics, and discuss future directions in the management of this phenotypic variant.

  13. Imaging Techniques in Acute Heart Failure.

    PubMed

    Pérez del Villar, Candelas; Yotti, Raquel; Bermejo, Javier

    2015-07-01

    In recent years, imaging techniques have revolutionized the diagnosis of heart failure. In patients with a clinical picture of acute decompensation, prognosis is largely determined by early implementation of general measures and treatment of the underlying cause. Given its diagnostic yield and portability, ultrasound has become an essential tool in the setting of acute heart failure, and is currently found in all medical departments involved in the care of the critically ill patient. Cardiac magnetic resonance and computed tomography allow detailed characterization of multiple aspects of cardiac structure and function that were previously unavailable. This helps guide and monitor many of the treatment decisions in the acute heart failure population in an entirely noninvasive way. This article aims to review the usefulness of the imaging techniques that are clinically relevant in the context of an episode of acute heart failure. We discuss the indications and limitations of these techniques in detail and describe the general principles for the appropriate interpretation of results.

  14. 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

  15. 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. PMID:26831575

  16. Modeling the effectiveness of nebulized terbutaline for decompensated chronic obstructive pulmonary disease patients in the emergency department.

    PubMed

    Gueho, Florian; Beaune, Sébastien; Devillier, Philippe; Urien, Saik; Faisy, Christophe

    2016-08-01

    Short-acting β2-agonists (SABA) are widely used in the emergency department (ED) to treat patients with decompensated chronic obstructive pulmonary disease (COPD). We sought to model the effectiveness of nebulized SABA (terbutaline) on clinically relevant parameters associated with a reduction in work of breathing or respiratory muscle fatigue in decompensated COPD patients admitted to the ED.Forty consecutive decompensated COPD patients (having received at least one dose of nebulized terbutaline during their stay in the ED) were included in an observational cohort study. The terbutaline dose received at time t was expressed as cumulative dose and as a rate (mg/day). The associations between the terbutaline dose and time-dependent outcome parameters (respiratory rate, heart rate, arterial blood gases, and, as a marker of terbutaline's systemic effect, serum potassium) were analyzed using a nonlinear, mixed-effects model. The effect of various covariates influencing terbutaline's effectiveness (baseline characteristics and concomitant treatments) was assessed on the model.Among the investigated patients, a total of 377 time-dependent observations were available for analysis. Neither the cumulative dose nor the dose rate at time t significantly influenced the arterial blood gas parameters or heart rate. The cumulative dose of terbutaline was associated with a lower serum potassium level (P < 0.001) and, less significantly, a lower respiratory frequency (P = 0.036). In a tertile analysis, the need for post-ED hospitalization was not associated with the cumulative dose or dose rate of terbutaline.Overall, the results of our modeling study strongly suggest that terbutaline dose did not influence time-dependent outcomes other than serum potassium, and thus call into question the systematic administration of inhaled SABA to patients admitted to the ED for decompensated COPD. PMID:27512880

  17. Modeling the effectiveness of nebulized terbutaline for decompensated chronic obstructive pulmonary disease patients in the emergency department

    PubMed Central

    Gueho, Florian; Beaune, Sébastien; Devillier, Philippe; Urien, Saik; Faisy, Christophe

    2016-01-01

    Abstract Short-acting β2-agonists (SABA) are widely used in the emergency department (ED) to treat patients with decompensated chronic obstructive pulmonary disease (COPD). We sought to model the effectiveness of nebulized SABA (terbutaline) on clinically relevant parameters associated with a reduction in work of breathing or respiratory muscle fatigue in decompensated COPD patients admitted to the ED. Forty consecutive decompensated COPD patients (having received at least one dose of nebulized terbutaline during their stay in the ED) were included in an observational cohort study. The terbutaline dose received at time t was expressed as cumulative dose and as a rate (mg/day). The associations between the terbutaline dose and time-dependent outcome parameters (respiratory rate, heart rate, arterial blood gases, and, as a marker of terbutaline's systemic effect, serum potassium) were analyzed using a nonlinear, mixed-effects model. The effect of various covariates influencing terbutaline's effectiveness (baseline characteristics and concomitant treatments) was assessed on the model. Among the investigated patients, a total of 377 time-dependent observations were available for analysis. Neither the cumulative dose nor the dose rate at time t significantly influenced the arterial blood gas parameters or heart rate. The cumulative dose of terbutaline was associated with a lower serum potassium level (P < 0.001) and, less significantly, a lower respiratory frequency (P = 0.036). In a tertile analysis, the need for post-ED hospitalization was not associated with the cumulative dose or dose rate of terbutaline. Overall, the results of our modeling study strongly suggest that terbutaline dose did not influence time-dependent outcomes other than serum potassium, and thus call into question the systematic administration of inhaled SABA to patients admitted to the ED for decompensated COPD. PMID:27512880

  18. 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

  19. Calcium sensitizer agents: a new class of inotropic agents in the treatment of decompensated heart failure.

    PubMed

    Perrone, Sergio V; Kaplinsky, Edgardo J

    2005-09-01

    The clinician's primary objective in treating a patient with decompensated heart failure is rapid and effective stabilization. This goal often is achieved through the use of inotropic support. Classic inotropic agents (beta-adrenergic agonists and phosphodiesterase III inhibitors) can provide short-term hemodynamic benefits, but their long-term use has been correlated with poor survival rates. Calcium sensitizers comprise a new drug class that offers hemodynamic and symptomatic improvements without increasing cAMP and intracellular calcium concentrations. These agents enhance contractility without a concurrent increase in the risk of cardiac events and thus represent a significant improvement over classic positive inotropic agents. Levosimendan is the most potent calcium sensitizer to date, exhibiting a unique dual mechanism of action that combines a positive inotropic action mediated via calcium sensitization and a vasodilator property via ATP-dependent potassium channels. Available clinical data suggest that calcium sensitizer agents represent a promising class of inotropic agents in a field that has seen few advances in recent decades.

  20. 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.

  1. Response and Tolerance to Oral Vasodilator Uptitration after Intravenous Vasodilator Therapy in Advanced Decompensated Heart Failure

    PubMed Central

    Verbrugge, Frederik H.; Dupont, Matthias; Finucan, Michael; Gabi, Alaa; Hawwa, Nael; Mullens, Wilfried; Taylor, David O.; Young, James B.; Starling, Randall C.; Wilson Tang, W.H.

    2015-01-01

    Aims To assess the hemodynamic response and tolerance to aggressive oral hydralazine/isosorbide dinitrate (HYD/ISDN) uptitration after intravenous vasodilator therapy in advanced decompensated heart failure (ADHF). Methods and Results Medical records of 147 consecutive ADHF patients who underwent placement of a pulmonary artery catheter and received intravenous vasodilator therapy were reviewed. Intravenous sodium nitroprusside and sodium nitroglycerin as first-line agent for those with preserved blood pressures were utilized in 143 and 32 patients, respectively. Sixty-one percent of patients were converted to oral HYD/ISDN combination therapy through a standardized conversion protocol. These patients had a significantly higher admission mean pulmonary arterial wedge pressure compared to patients not converted (28 ± 7 versus 25 ± 8 mmHg, respectively; P-value=0.024). Beneficial hemodynamic response to decongestive therapy, defined as low cardiac filling pressures and cardiac index ≥2.20 L/min/m² without emergent hypotension, was achieved in 32% and 29% of patients who did or did not receive oral HYD/ISDN, respectively (P-value=0.762). HYD/ISDN dosing was progressively and consistently decreased up to the moment of hospital discharge and during outpatient follow-up primarily due to incident hypotension. Conclusion The use of a standardized hemodynamically-guided uptitration protocol for conversion from intravenous to oral vasodilators may warrant subsequent dose reductions upon stabilization. PMID:26213182

  2. 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

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

    PubMed

    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.

  4. Can HF heating generate ESF bubbles?

    NASA Astrophysics Data System (ADS)

    Zawdie, K. A.; Huba, J. D.

    2014-12-01

    The injection of powerful HF waves into the ionosphere can lead to strong electron heating followed by a pressure perturbation which can locally reduce the plasma density. In the postsunset equatorial ionosphere, density perturbations can provide the seed to generate equatorial spread F (ESF) bubbles. In this paper, a modified version of the SAMI3/ESF ionosphere code is used to model the density depletions created by HF heating and to determine if ESF bubbles can be artificially generated. It is found that HF heating primarily redistributes plasma along the geomagnetic field and does not significantly perturb the flux tube integrated conductivities. Thus, HF heating does not appear to be a viable method to seed or generate ESF bubbles.

  5. Rationale and design of a pilot randomized controlled trial to assess the role of intravenous ferric carboxymaltose in Asian patients with heart failure (PRACTICE‐ASIA‐HF)

    PubMed Central

    Yeo, Poh Shuan Daniel; Hadi, Farid Abdul; Cushway, Timothy; Lee, Kim Yee; Tai, Bee Choo

    2015-01-01

    Abstract Aims Iron deficiency (ID) is highly prevalent in patients with heart failure (HF) worldwide regardless of haemoglobin levels. Results from therapeutic trials of intermittently dosed intravenous (i.v.) iron are promising in the ambulatory Caucasian population with HF with reduced left ventricular ejection fraction, although evidence is scarce in Asia. The Pilot Randomized Controlled Trial to Assess the Role of Intravenous Ferric Carboxymaltose in Asian Patients with Heart Failure aims to assess the effect of single‐dose i.v. ferric carboxymaltose (FCM) in a multi‐ethnic Asian population with HF and ID. Methods and results This is an open‐label, randomized, placebo‐controlled trial recruiting stabilized inpatients with decompensated HF (regardless of left ventricular ejection fraction), ID [defined as serum ferritin <300 ng/mL if transferrin saturation <20%] and haemoglobin ≤14 g/dL. Patients from two tertiary institutions were randomized in a 1:1 ratio to receive a single dose of either i.v. FCM (Ferinject®) 1000 mg or i.v. normal saline. The primary endpoint is the change in 6‐min walk distance at Weeks 4 and 12, and secondary endpoints are changes at Weeks 4 and 12 in (i) quality of life as measured by the Kansas City Cardiomyopathy Questionnaire and Visual Analogue Scale scores and (ii) New York Heart Association functional class. Conclusions Preliminary efficacy data on i.v. FCM therapy in Asian HF are expected from this pilot study to support larger‐scale multicentre therapeutic i.v. FCM trials within Asia.

  6. High baseline bilirubin and low albumin predict liver decompensation and serious adverse events in HCV-infected patients treated with sofosbuvir-containing regimens.

    PubMed

    Perumalswami, P V; Patel, N; Bichoupan, K; Ku, L; Yalamanchili, R; Harty, A; Motamed, D; Khaitova, V; Chang, C; Grewal, P; Liu, L; Schiano, T D; Woodward, M; Dieterich, D T; Branch, A D

    2016-09-01

    To conduct surveillance and determine the safety profile of new hepatitis C virus treatments in real-world clinical practice. Hepatic decompensation and other serious adverse events were investigated in an observational cohort study of 511 patients treated with regimens containing sofosbuvir, December 2013-June 2014. Among 499 previously stable patients (no history of hepatic decompensation during the previous 12 months), a nested case-control study was performed to identify predictors of decompensation/serious adverse event. Cases and controls were matched 1:5 based on treatment regimen and duration. Matched conditional logistic regression was used for analysis. Providers scored the likelihood that events were treatment-related (scale = 0-4). The cumulative incidence of decompensation/events was 6.4% for the total cohort. Among 499 previously stable patients, the incidence of decompensation/events was 4.5%; the mortality rate was 0.6%. Sixteen of the 499 experienced one or more serious complications considered to be at least potentially treatment-related, and the sustained virological response rate was 7/16 (44%). Two cases, both on sofosbuvir/simeprevir (without interferon or ribavirin), had complications consistent with autoimmune events (score 3, 'likely treatment-related'), and one experienced a flare of autoimmune hepatitis. Compared to controls, cases had higher baseline median model for end-stage liver disease scores (14 vs 8, P < 0.01). Decompensation/events was independently associated with lower baseline albumin (OR = 0.12/g/dL, P = 0.01) and higher total bilirubin (OR = 4.31/mg/dL, P = 0.01). Reduced hepatic function at baseline increased the risk of liver decompensation/events.

  7. High baseline bilirubin and low albumin predict liver decompensation and serious adverse events in HCV-infected patients treated with sofosbuvir-containing regimens.

    PubMed

    Perumalswami, P V; Patel, N; Bichoupan, K; Ku, L; Yalamanchili, R; Harty, A; Motamed, D; Khaitova, V; Chang, C; Grewal, P; Liu, L; Schiano, T D; Woodward, M; Dieterich, D T; Branch, A D

    2016-09-01

    To conduct surveillance and determine the safety profile of new hepatitis C virus treatments in real-world clinical practice. Hepatic decompensation and other serious adverse events were investigated in an observational cohort study of 511 patients treated with regimens containing sofosbuvir, December 2013-June 2014. Among 499 previously stable patients (no history of hepatic decompensation during the previous 12 months), a nested case-control study was performed to identify predictors of decompensation/serious adverse event. Cases and controls were matched 1:5 based on treatment regimen and duration. Matched conditional logistic regression was used for analysis. Providers scored the likelihood that events were treatment-related (scale = 0-4). The cumulative incidence of decompensation/events was 6.4% for the total cohort. Among 499 previously stable patients, the incidence of decompensation/events was 4.5%; the mortality rate was 0.6%. Sixteen of the 499 experienced one or more serious complications considered to be at least potentially treatment-related, and the sustained virological response rate was 7/16 (44%). Two cases, both on sofosbuvir/simeprevir (without interferon or ribavirin), had complications consistent with autoimmune events (score 3, 'likely treatment-related'), and one experienced a flare of autoimmune hepatitis. Compared to controls, cases had higher baseline median model for end-stage liver disease scores (14 vs 8, P < 0.01). Decompensation/events was independently associated with lower baseline albumin (OR = 0.12/g/dL, P = 0.01) and higher total bilirubin (OR = 4.31/mg/dL, P = 0.01). Reduced hepatic function at baseline increased the risk of liver decompensation/events. PMID:26989855

  8. A disproportionate elevation in right ventricular filling pressure, in relation to left ventricular filling pressure, is associated with renal impairment and increased mortality in advanced decompensated heart failure

    PubMed Central

    Grodin, Justin L.; Drazner, Mark H.; Dupont, Matthias; Mullens, Wilfried; Taylor, David O.; Starling, Randall C.; Tang, W. H. Wilson

    2015-01-01

    Background Discordance between left- and right-sided filling pressures occurs in a subset of patients presenting with acute decompensated heart failure (ADHF). We hypothesized that a disproportionately increased right atrial pressure (RAP) relative to the pulmonary capillary wedge pressure (PCWP) would be associated with both renal dysfunction and mortality in ADHF. Methods A total of 367 patients admitted with ADHF with elevated intracardiac filling pressures were treated with intensive medical therapy guided by invasive hemodynamic monitoring. Baseline characteristics, hemodynamics, and renal function at admission were stratified by RAP/PCWP quartiles. The association of RAP/PCWP quartile with all-cause mortality after a median follow-up of 2.4 years was assessed in univariable and multivariable models, which included adjustment for the RAP. Results The median RAP/PCWP was 0.58 (interquartile range 0.43-0.75). Increasing RAP/PCWP was inversely associated with estimated glomerular filtration rate at baseline and with treatment (P < .0001) independently of RAP. High RAP/PCWP was associated with increased mortality (quartile 4 vs 1: hazard ratio [95% CI] 2.1 [1.3-3.5], P = .002). The association of RAP/PCWP with mortality persisted after adjustment for age, gender, mean arterial pressure, RAP, cardiac index, pulmonary vascular resistance, and estimated glomerular filtration rate (hazard ratio 2.4 [1.4-3.9], P = .007). Conclusion A disproportionate increase in right to left ventricular filling pressures is associated with renal dysfunction and mortality, independently of the right atrial pressure. PMID:26027618

  9. Micronutrients in African-Americans with decompensated and compensated heart failure.

    PubMed

    Arroyo, Maximiliano; Laguardia, Stephen P; Bhattacharya, Syamal K; Nelson, Maeda D; Johnson, Patti L; Carbone, Laura D; Newman, Kevin P; Weber, Karl T

    2006-12-01

    Heart failure is thought to be more common and of greater severity in African-Americans (AAs). Potential mechanisms remain uncertain. The importance of micronutrient deficiencies in the pathophysiologic expression of congestive heart failure (CHF) in AAs remains to be explored, including hypovitaminosis D, which can promote secondary hyperparathyroidism (SHPT), together with hypozincemia and hyposelenemia, the 2 most crucial trace minerals integral to diverse biologic functions. Serum parathyroid hormone (PTH), 25-hydroxyvitamin D (25(OH)D), Zn, and Se were monitored in 30 AAs hospitalized during June through December 2005, with decompensated failure and reduced ejection fraction (EF) (<35%) of predominantly nonischemic origin treated with an angiotensin-converting enzyme (ACE) inhibitor or an angiotensin receptor blocker (ARB), furosemide, and spironolactone. Based on their symptomatic status before hospitalization, 15 patients were stratified as having protracted (>or=4 weeks) CHF, whereas 15 patients had short-term (1-2 weeks) CHF. These hospitalized patients were compared with 10 AA outpatients with stable, similarly treated compensated failure and comparable EF, and 9 AA normal volunteers without cardiovascular disease. Serum PTH was elevated in all patients with protracted CHF and in 60% of patients with short-term CHF, but not in compensated patients or normal volunteers. However, serum 25(OH)D was reduced in all patients with >or=4 weeks and 80% with either 1-2 weeks CHF or compensated failure compared with volunteers. Serum Zn was below normal in 11 of 15 patients with protracted CHF, in 8 of 15 patients with shorter duration CHF, and in 5 of 10 patients with compensated failure. Serum Se was reduced in all patients with >or=4 weeks, 60% with short-term CHF, and 90% of compensated patients. Concomitant to hypovitaminosis D, hypozincemia, and hyposelenemia, SHPT is a covariant of CHF in housebound AAs. PMID:17162251

  10. 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

  11. 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

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

    SciTech Connect

    Fujimaki, H.; Tatsumoto, M.

    1984-02-15

    Very low Ti basalts andd green glass samples from the moon show high Lu/Hf ratios and low Hf concentrations. Low-Ti lunar basalts show high and variable Lu/Hf ratios and higher Hf concentrations, whereas high-Ti lunar basalts show low Lu/Hf ratios and high Hf concentrations. KREEP basalts have constant Lu/Hf ratios and high but variable Hf concentrations. Using the Lu-Hf behavior as a constraint, we propose a model for the mare basalts evolution. This constraint requires extensive crystallization of the primary lunar magma ocean prior to formation of the lunar mare basalt sources and the KREEP basalts. Mare basalts are produced by the melting of the cumulate rocks, and KREEP basalts represent the residual liquid of the magma ocean.

  13. Acute Onset Anti-Synthetase Syndrome With Pericardial Effusion and Non-Specific Interstitial Pneumonia

    PubMed Central

    Shah, Aditya; Patel, Samir R.

    2016-01-01

    Anti-synthetase syndrome (AS) is a clinical entity which is described classically by the triad of interstitial lung disease (ILD), inflammatory myositis and presence of aminoacyl-tRNA synthetase antibodies (ASA). We describe a rare presentation of this condition with regard to the uncharacteristically acute nature of presentation, acute decompensation in clinical condition, development of acute interstitial pneumonitis requiring rescue extracorporeal membrane oxygenation (ECMO) and accompaniment of significant pericardial effusion on presentation, followed by rapid improvement with initiation of steroids. PMID:27540445

  14. 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.

  15. Predischarge initiation of carvedilol in patients hospitalized for decompensated heart failure.

    PubMed

    Gattis, Wendy A; O'Connor, Christopher M

    2004-05-01

    The use of beta-blockers for the treatment of heart failure in the United States is inadequate, despite available data and current guidelines that support their use. The Initiation Management Predischarge: Process for Assessment of Carvedilol Therapy for Heart Failure (IMPACT-HF) study was designed to determine whether initiation of beta-blockade before hospital discharge is safe and effective in improving the 60-day use of beta-blockers in patients with heart failure. IMPACT-HF compared the strategy of the initiation of carvedilol before patients were discharged versus usual care (Heart Failure Society of America guidelines recommend waiting 2 to 4 weeks after hospitalization for heart failure before initiating beta-blocker therapy) in 363 randomized patients with heart failure. The entry criteria were non-restrictive to ensure inclusion of patients reflective of the general heart failure population. The primary end point of the study (the number of patients treated with any beta-blocker at 60 days) was statistically significantly higher in the predischarge group versus the postdischarge group (91.2% vs 73.4%, respectively). Based on the study's results, predischarge initiation may be a successful strategy to improve the use of beta-blocker therapy for patients with heart failure.

  16. Comparison of HfCl4, HfI4, TEMA-Hf, and TDMA-Hf as precursors in early growing stages of HfO2 films deposited by ALD: A DFT study

    NASA Astrophysics Data System (ADS)

    Cortez-Valadez, M.; Fierro, C.; Farias-Mancilla, J. R.; Vargas-Ortiz, A.; Flores-Acosta, M.; Ramírez-Bon, R.; Enriquez-Carrejo, J. L.; Soubervielle-Montalvo, C.; Mani-Gonzalez, P. G.

    2016-06-01

    The final structure of HfO2 films grown by atomic layer deposition (ALD) after reaction with OH- ions has been analyzed by DFT (density functional theory). The interaction of the precursors: HfCl4 (hafnium tetrachloride), HfI4 (hafnium tetraiodide), TEMA-Hf (tetrakis-ethylmethylamino hafnium), and TDMA-Hf (tetrakis-dimethylamino hafnium) with HO-H was studied employing the B3LYP (Becke 3-parameter, Lee-Yang-Parr) hybrid functional and the PBE (Perdew-Burke-Ernzerhof) generalized gradient functional. The structural evolution at the Si(100) surface has been analyzed by LDA (local density approximation). The structural parameters: bond length and bond angle, and the vibrational parameters for the optimized structures are also reported. The presence of hafnium silicate at the interface was detected. The infrared spectra and structural parameters obtained in this work agree with previously reported experimental results.

  17. 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.

  18. HF emissions in manufacturing traditional ceramics

    SciTech Connect

    Brosnan, D.A.

    1997-01-01

    Hydrogen fluoride (HF) evolves in kiln drafts during the preheating of clay-based ceramics. The fluorine source is clay dehydroxylation, i.e., the decomposition of clay crystals. Fluorine evolution can continue in the kiln soak zone as fluorine compounds formed during the initial fluorine-evolution period eventually decompose. Because North America clays exhibit a wide range of fluorine content--typically 200--1,200 ppm--the quantity of HF emitted varies considerably from one manufacturing site to another. Variables in firing--such as preheat rate, soak temperature and exit gas temperature--also affect the emission quantity. Because HF is classified as a hazardous air pollutant under the US Clean Air Act, it is subject to federal regulation, and individual states can impose more stringent regulations than the federal standards. Several states already have imposed such regulations.

  19. 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.

  20. 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

  1. [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.

  2. Sleep and circadian rhythms in hospitalized patients with decompensated cirrhosis: effect of light therapy.

    PubMed

    De Rui, M; Middleton, B; Sticca, A; Gatta, A; Amodio, P; Skene, D J; Montagnese, S

    2015-02-01

    , decompensated patients with cirrhosis are extremely compromised. Treatment with bright light therapy did not show obvious, beneficial effects, most likely in relation to the severity of disturbance at baseline. PMID:25135598

  3. 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.

  4. Rapid Progression to Decompensated Cirrhosis, Liver Transplant, and Death in HIV-Infected Men After Primary Hepatitis C Virus Infection

    PubMed Central

    Fierer, Daniel S.; Dieterich, Douglas T.; Fiel, M. Isabel; Branch, Andrea D.; Marks, Kristen M.; Fusco, Dahlene N.; Hsu, Ricky; Smith, Davey M.; Fierer, Joshua

    2013-01-01

    Background. We and others have shown that primary hepatitis C (HCV) infection in men infected with human immunodeficiency virus (HIV) causes early-onset liver fibrosis; however, little is known about the long-term natural history of the liver disease in these HIV-infected men. Methods. We followed a cohort of HIV-infected men with primary HCV infection in New York City. Results. Four men who were not cured after their primary HCV infection developed decompensated cirrhosis within 17 months to 6 years after primary HCV infection. Three died within 8 years of primary HCV infection, and 1 survived after liver transplant done 2 years after primary HCV infection. Three of the 4 men had AIDS at the time of primary HCV infection, and the most rapid progression occurred in the 2 men with the lowest CD4 counts at the time of HCV infection. Liver histopathology was most consistent with HCV-induced damage even though some had exposures to other potential hepatotoxins. Conclusions. Primary HCV infection resulted in decompensated cirrhosis and death within 2–8 years in 4 HIV-infected men. The rapid onset of fibrosis due to primary HCV infection in HIV-infected men cannot therefore be considered benign. The rate of continued progression to liver failure may be proportional to the degree of underlying immunocompromise caused by HIV infection. More research is needed to better define the mechanisms behind accelerated liver damage. PMID:23264364

  5. 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

  6. Na(+)-K(+)-ATPase alpha(2)-isoform expression in guinea pig hearts during transition from compensation to decompensation.

    PubMed

    Trouve, P; Carre, F; Belikova, I; Leclercq, C; Dakhli, T; Soufir, L; Coquard, I; Ramirez-Gil, J; Charlemagne, D

    2000-10-01

    Disturbance in ionic gradient across sarcolemma may lead to arrhythmias. Because Na(+)-K(+)-ATPase regulates intracellular Na(+) and K(+) concentrations, and therefore intracellular Ca(2+) concentration homeostasis, our aim was to determine whether changes in the Na(+)-K(+)-ATPase alpha-isoforms in guinea pigs during transition from compensated (CLVH) to decompensated left ventricular hypertrophy (DLVH) were concomitant with arrhythmias. After 12- and 20-mo aortic stenosis, CLVH and DLVH were characterized by increased mean arterial pressure (30% and 52.7%, respectively). DLVH differed from CLVH by significantly increased end-diastolic pressure (34%), decreased sarco(endo)plasmic reticulum Ca(2+)-ATPase (-75%), and increased Na(+)/Ca(2+) exchanger (25%) mRNA levels and by the occurrence of ventricular arrhythmias. The alpha-isoform (mRNA and protein levels) was significantly lower in DLVH (2.2 +/- 0.2- and 1. 4 +/- 0.15-fold, respectively, vs. control) than in CLVH (3.5 +/- 0. 4- and 2.2 +/- 0.13-fold, respectively) and was present in sarcolemma and T tubules. Changes in the levels of alpha(1)- and alpha(3)-isoform in CLVH and DLVH appear physiologically irrelevant. We suggest that the increased level of alpha(2)-isoform in CLVH may participate in compensation, whereas its relative decrease in DLVH may enhance decompensation and arrhythmias. PMID:11009487

  7. 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.

  8. Origin of Excess 176Hf in Meteorites

    NASA Astrophysics Data System (ADS)

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

    2010-07-01

    After considerable controversy regarding the 176Lu decay constant (λ176Lu), there is now widespread agreement that (1.867 ± 0.008) × 10-11 yr-1 as confirmed by various terrestrial objects and a 4557 Myr meteorite is correct. This leaves the 176Hf excesses that are correlated with Lu/Hf elemental ratios in meteorites older than ~4.56 Ga meteorites unresolved. We attribute 176Hf excess in older meteorites to an accelerated decay of 176Lu caused by excitation of the long-lived 176Lu ground state to a short-lived 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 176Hf with depth of burial at the time of the irradiation event.

  9. Characteristics of HfO2/Hf-based bipolar resistive memories

    NASA Astrophysics Data System (ADS)

    Jinshun, Bi; Zhengsheng, Han

    2015-06-01

    Nano-scale Hf/HfO2-based resistive random-access-memory (RRAM) devices were fabricated. The cross-over between top and bottom electrodes of RRAM forms the metal-insulator-metal sandwich structure. The electrical responses of RRAM are studied in detail, including forming process, SET process and RESET process. The correlations between SET voltage and RESET voltage, high resistance state and low resistance state are discussed. The electrical characteristics of RRAM are in a strong relationship with the compliance current in the SET process. The conduction mechanism of nano-scale Hf/HfO2-based RRAM can be explained by the quantum point contact model. Project supported by the National Natural Science Foundation of China (Nos. 11179003, 61176095).

  10. Simultaneous observation of HF-enhanced plasma waves and HF-wave self-focusing

    SciTech Connect

    Frey, A.; Duncan, L.M.

    1984-07-01

    Intense HF-radiowaves of the ordinary mode transmitted from the ground enhance plasma waves near the reflection height. These have been extensively studied in the past by the use of Incohernt-Scatter-Radars. Intense HF-radiowaves propagating in the ionosphere also produce electron density irregularities with scale sizes much larger than the HF wavelength of approx.60 m. These have been observed by radio star intensity scintillations. For the past 2 years a new method was used at Arecibo, P.R. which allows radar- and scintillation-measurements at 430 MHz to be performed simultaneously along the same line of sight. The scale sizes deduced from the scintillation measurements are shorter than the scale sizes observed with the radar and are inconsistent with the HF-power density thresholds predicted by existing theories.

  11. 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

  12. 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

    2016-08-01

    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.

  13. K = 6+ Isomers in Hf, yb and W Nuclei

    NASA Astrophysics Data System (ADS)

    Rath, Aswini Kumar; Walker, P. M.; Praharaj, C. R.; Xu, F. R.

    Using deformed Hartree-Fock and angular momentum projection (PHF) technique we try to understand the intrinsic structure and the systematics in the life times of K = 6+ isomers in the Hf isotopes (in 172-178Hf nuclei) and N = 104 Yb, Hf and W isotones. The band structure in 172Hf is reasonably well reproduced. The variation in the B(E2;2+ → 0+) values in the Hf isotopes as well as N = 104 isotones are well reproduced. The calculated K-forbidden E2 transition probabilities from the isomer bandheads to the 4+ yrast states qualitatively explain the variation of the lifetimes with N and Z.

  14. 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.

  15. 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

  16. The WISP/HF system for Spacelab

    NASA Technical Reports Server (NTRS)

    James, H. G.

    1980-01-01

    The high frequency part of the waves in space plasmas system, WISP/HF, is a flexible shuttle Spacelab instrument for transmitting, receiving, and processing signals in the 0.3 to 30 MHz range. It permits a wide range of plasma wave experiments in the ionosphere including studies of the transmitting antenna, fundamentals of electromagnetic (EM) and electrostatic (ES) waves in magnetoplasmas, instabilities and nonlinearities, and remote sounding of ionospheric structure. Collaborative investigations involving other WISP equipment (e.g., antenna and propagation studies with the WISP/VLF system) or other Spacelab facilities (e.g., beam plasma interactions using charged particle guns) are envisaged. A few specific examples illustrate the relevance of WISP/HF to current scientific interest. The overall goal is to help build a comprehensive understanding of plasmaspheric wave physics through group studies.

  17. Studies of dispersion energy in hydrogen-bonded systems. H2O-HOH, H2O-HF, H3N-HF, HF-HF

    NASA Astrophysics Data System (ADS)

    Szcześniak, M. M.; Scheiner, Steve

    1984-02-01

    Dispersion energy is calculated in the systems H2O-HOH, H2O-HF, H3N-HF, and HF-HF as a function of the intermolecular separation using a variety of methods. M≂ller-Plesset perturbation theory to second and third orders is applied in conjunction with polarized basis sets of 6-311G** type and with an extended basis set including a second set of polarization functions (DZ+2P). These results are compared to a multipole expansion of the dispersion energy, based on the Unsöld approximation, carried out to the inverse tenth power of the intermolecular distance. Pairwise evaluation is also carried out using both atom-atom and bond-bond formulations. The MP3/6-311G** results are in generally excellent accord with the leading R-6 term of the multipole expansion. This expansion, if carried out to the R-10 term, reproduces extremely well previously reported dispersion energies calculated via variation-perturbation theory. Little damping of the expansion is required for intermolecular distances equal to or greater than the equilibrium separation. Although the asymptotic behavior of the MP2 dispersion energy is somewhat different than that of the other methods, augmentation of the basis set by a second diffuse set of d functions leads to quite good agreement in the vicinity of the minima. Both the atom-atom and bond-bond parametrization schemes are in good qualitative agreement with the other methods tested. All approaches produce similar dependence of the dispersion energy upon the angular orientation between the two molecules involved in the H bond.

  18. Efficacy and safety of nesiritide in patients with decompensated heart failure: a meta-analysis of randomised trials

    PubMed Central

    Gong, Bojun; Wu, Zhineng; Li, Zicheng

    2016-01-01

    Objectives Current evidence suggests that nesiritide may have effects on renal function and decrease the incidence of mortality. However, a clear superiority using nesiritide in terms of renal toxicity and mortality in patients with heart failure was not consistently proven by previous studies. We performed a meta-analysis of all randomised trials to obtain the best estimates of efficacy and safety of nesiritide for the initial treatment of decompensated heart failure. Method We performed a meta-analysis of randomised trials of nesiritide in patients with decompensated heart failure (n=38 064 patients, in 22 trials). Two reviewers independently extracted data. Data on efficacy and safety outcomes were collected. We calculated pooled relatives risk (RRs), weighted mean difference and associated 95% CIs. Results Compared with placebo, dobutamine and nitroglycerin, nesiritide indicated no increasing risk of total mortality. Compared with the combined control therapy, nesiritide was associated with non-significant differences in short-term mortality (RR 1.24; 95% CI 0.85 to 1.80; p=0.27), mid-term mortality (RR 0.86; 95% CI 0.60 to 1.24; p=0.42) and long-term mortality (RR 0.94; 95% CI 0.75 to 1.18; p=0.61). Nesiritide therapy increased the risk of hypotension (p<0.00 001) and bradycardia (p=0.02) when compared with control therapy. Compared with dobutamine or placebo therapy, no differences in serum creatinine, blood urea nitrogen and creatinine clearance, and no risk of the need for dialysis was observed in nesiritide therapy. Conclusions Our findings indicated that, in patients with heart failure, nesiritide was not associated with the risk of mortality. However, it increased the risk of cardiovascular adverse events. The change of serum creatinine and creatinine clearance had no significant difference, and no risk of the need for dialysis was observed after low-dose nesiritide treatment. PMID:26739721

  19. SERVE-HF: More Questions Than Answers.

    PubMed

    Javaheri, Shahrokh; Brown, Lee K; Randerath, Winfried; Khayat, Rami

    2016-04-01

    The recent online publication of the SERVE-HF trial that evaluated the effect of treating central sleep apnea (CSA) with an adaptive servoventilation (ASV) device in patients with heart failure and reduced ejection fraction (HFrEF) has raised serious concerns about the safety of ASV in these patients. Not only was ASV ineffective but post hoc analysis found excess cardiovascular mortality in treated patients. The authors cited as one explanation an unfounded notion that CSA is a compensatory mechanism with a protective effect in HFrEF patients. We believe that there are several possible considerations that are more likely to explain the results of SERVE-HF. In this commentary, we consider methodological issues including the use of a previous-generation ASV device that constrained therapeutic settings to choices that are no longer in wide clinical use. Patient selection, data collection, and treatment adherence as well as group crossovers were not discussed in the trial as potential confounding factors. We have developed alternative reasons that could potentially explain the results and that can be explored by post hoc analysis of the SERVE-HF data. We believe that our analysis is of critical value to the field and of particular importance to clinicians treating these patients. PMID:26836904

  20. 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.

  1. 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

  2. Cystitis - acute

    MedlinePlus

    Uncomplicated urinary tract infection; UTI - acute; Acute bladder infection; Acute bacterial cystitis ... International clinical practice guidelines for the treatment of acute uncomplicated cystitis and pyelonephritis in women: A 2010 ...

  3. Preliminary observations of lung injury produced by instillation of HF in acidic and neutral buffer

    SciTech Connect

    Brainard, J.R.; Kinkead, S.A.; Kober, E.M.; Sebring, R.J.; Stavert, D.M.; Lehnert, B.E.

    1990-01-01

    Perfluoroisobutylene (PFIB) is an extremely toxic organofluoride that can be produced during pyrolysis of tetrafluoroethylene polymers, including Teflon{reg sign}. Inhalation of PFIB at very low concentrations causes acute lung injury, the hallmark of which is pulmonary edema. Several lines of evidence have suggested that hydrolysis of PFIB and resulting production of hydrofluoric acid may be responsible for pulmonary damage. In order to investigate the potential involvement of hydrofluoric acid in producing lung injury and its relationship to the mechanism of fluorocarbon toxicity, we have compared the pulmonary injury produced by PFIB, by dissociated (H{sup +} and F{sup {minus}}), and by undissociated (HF) hydrofluoric acid in the deep lung. By delivering hydrofluoric acid by intratracheal instillation in neutral buffer, we demonstrate that F{sup {minus}} produces no significant pulmonary injury as assessed by increased in lung weight and ultrastructural changes. Similarly, instillation of acid buffer alone demonstrated that H{sup +} did not produce detectable lung injury. Instillation of HF produced changes in lung weight and ultrastructure similar to those observed in PFIB-treated rats. However, the ultrastructural studies show that in contrast to inhalation of PFIB, which produces both endothelial and epithelial cell damage, instillation of HF appears to exert its injurious effects only upon epithelial cells. 9 refs., 1 fig.

  4. 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.

  5. Synthesis and structural investigation of the compounds containing HF 2- anions: Ca(HF 2) 2, Ba 4F 4(HF 2)(PF 6) 3 and Pb 2F 2(HF 2)(PF 6)

    NASA Astrophysics Data System (ADS)

    Bunič, Tina; Tramšek, Melita; Goreshnik, Evgeny; Žemva, Boris

    2008-09-01

    Three new compounds Ca(HF 2) 2, Ba 4F 4(HF 2)(PF 6) 3 and Pb 2F 2(HF 2)(PF 6) were obtained in the system metal(II) fluoride and anhydrous HF (aHF) acidified with excessive PF 5. The obtained polymeric solids are slightly soluble in aHF and they crystallize out of their aHF solutions. Ca(HF 2) 2 was prepared by simply dissolving CaF 2 in a neutral aHF. It represents the second known compound with homoleptic HF environment of the central atom besides Ba(H 3F 4) 2. The compounds Ba 4F 4(HF 2)(PF 6) 3 and Pb 2F 2(HF 2)(PF 6) represent two additional examples of the formation of a polymeric zigzag ladder or ribbon composed of metal cation and fluoride anion (MF +) n besides PbF(AsF 6), the first isolated compound with such zigzag ladder. The obtained new compounds were characterized by X-ray single crystal diffraction method and partly by Raman spectroscopy. Ba 4F 4(HF 2)(PF 6) 3 crystallizes in a triclinic space group P1¯ with a=4.5870(2) Å, b=8.8327(3) Å, c=11.2489(3) Å, α=67.758(9)°, β=84.722(12), γ=78.283(12)°, V=413.00(3) Å 3 at 200 K, Z=1 and R=0.0588. Pb 2F 2(HF 2)(PF 6) at 200 K: space group P1¯, a=4.5722(19) Å, b=4.763(2) Å, c=8.818(4) Å, α=86.967(10)°, β=76.774(10)°, γ=83.230(12)°, V=185.55(14) Å 3, Z=1 and R=0.0937. Pb 2F 2(HF 2)(PF 6) at 293 K: space group P1¯, a=4.586(2) Å, b=4.781(3) Å, c=8.831(5) Å, α=87.106(13)°, β=76.830(13)°, γ=83.531(11)°, V=187.27(18) Å 3, Z=1 and R=0.072. Ca(HF 2) 2 crystallizes in an orthorhombic Fddd space group with a=5.5709(6) Å, b=10.1111(9) Å, c=10.5945(10) Å, V=596.77(10) Å 3 at 200 K, Z=8 and R=0.028.

  6. 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

  7. 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.

  8. Splanchnic and renal elimination and release of catecholamines in cirrhosis. Evidence of enhanced sympathetic nervous activity in patients with decompensated cirrhosis.

    PubMed Central

    Henriksen, J H; Ring-Larsen, H; Kanstrup, I L; Christensen, N J

    1984-01-01

    Plasma noradrenaline (NA) and adrenaline (A) concentrations were determined in different vascular areas in 32 patients with cirrhosis and in nine controls during a right sided heart, liver, and renal vein catheterisation. The patients were divided into four groups: (I) Compensated (without ascites); (II) Recompensated on diuretic treatment because of former ascites; (III) Decompensated (with ascites) without treatment and (IV) Decompensated on diuretic treatment. Median arterial noradrenaline concentrations were 1.48, 1.07, 2.66, 4.14 and 2.50 nmol/l in controls, group I, II, III, and IV, respectively, the three last mentioned values being significantly raised (p less than 0.01). Median arterial adrenaline concentrations were not significantly increased. In patients arterial-hepatic venous extraction ratios of noradrenaline and adrenaline were on the average 25% (p less than 0.01) and 20% (p less than 0.02) less than those of the controls, indicating a slightly reduced splanchnic elimination of catecholamines in cirrhoses. In controls and group I significant renal venous-arterial noradrenaline differences were absent (0.00 and 0.03 nmol/l) while renal venous-arterial noradrenaline differences were significantly increased in groups II, III and IV (0.47, 0.53 and 0.68 nmol/l, p less than 0.01), indicating a significant net release of noradrenaline from the kidneys in recompensated and decompensated patients. Renal extraction of adrenaline was normal. In conclusion, increased arterial noradrenaline in decompensated and recompensated cirrhosis is only to a limited extent owing to reduced net splanchnic elimination. More likely the increase is caused by release of noradrenaline from the kidneys and possibly other organs indicating enhanced sympathetic nervous tone in these conditions. PMID:6479678

  9. Hf-W chronometry of primitive achondrites

    NASA Astrophysics Data System (ADS)

    Schulz, T.; Münker, C.; Mezger, K.; Palme, H.

    2010-03-01

    Metal segregation and silicate melting on asteroids are the most incisive differentiation events in the early evolution of planetary bodies. The timing of these events can be constrained using the short-lived 182Hf- 182W radionuclide system. Here we present new 182Hf- 182W data for major types of primitive achondrites including acapulcoites, winonaites and one lodranite. These meteorites are of particular interest because they show only limited evidence for partial melting of silicates and are therefore intermediate between chondrites and achondrites. For acapulcoites we derived a 182Hf- 182W age of Δ tCAI = 4.1 +1.2/ -1.1 Ma. A model age for winonaite separates calculated from the intercept of the isochron defines an age of Δ tCAI = 4.8 +3.1/ -2.6 Ma (assuming a bulk Hf/W ratio of ˜1.2). Both ages most likely define primary magmatic events on the respective parent bodies, such as melting of metal, although metal stayed in place and did not segregate to form a core. A later thermal event is responsible for resetting of the winonaite isochron, yielding an age of Δ tCAI = 14.3 +2.7/ -2.2 Ma, significantly younger than the model age. Assuming a co-genetic relationship between winonaites and silicates present in IAB iron meteorites (based on oxygen isotope composition) and including data by Schulz et al. (2009), a common parent body chronology can be established. Magmatic activity occurred between ˜1.5 and 5 Ma after CAIs. More than 5 Ma later, intensive thermal metamorphism has redistributed Hf-W. Average cooling rates calculated for the winonaite/IAB parent asteroid range between ˜35 and ˜4 K/Ma, most likely reflecting different burial depths. Cooling rates obtained for acapulcoites were ˜40 K/Ma to ˜720 K and then ˜3 K/Ma to ˜550 K. Accretion and subsequent magmatism on the acapulcoite parent body occurred slightly later if compared to most achondrite parent bodies (e.g., angrites, ureilites and eucrites), in this case supporting the concept of an inverse

  10. 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.

  11. Hepatitis C in Special Patient Cohorts: New Opportunities in Decompensated Liver Cirrhosis, End-Stage Renal Disease and Transplant Medicine

    PubMed Central

    Hüsing, Anna; Kabar, Iyad; Schmidt, Hartmut H.; Heinzow, Hauke S.

    2015-01-01

    Worldwide, hepatitis C virus (HCV) is a common infection. Due to new antiviral approaches and the approval of direct-acting antiviral agents (DAA), HCV therapy has become more comfortable. Nevertheless, there are special patient groups, in whom treatment of HCV is still challenging. Due to only few data available, tolerability and efficacy of DAAs in special patient cohorts still remain unclear. Such special patient cohorts comprise HCV in patients with decompensated liver disease (Child-Pugh Class B or C), patients with chronic kidney disease, and patients on waiting lists to renal/liver transplantation or those with HCV recurrence after liver transplantation. HCV infection in these patient cohorts has been shown to be associated with increased morbidity and mortality and may lead to reduced graft survival after transplantation. Successful eradication of HCV results in a better outcome concerning liver-related complications and in a better clinical outcome of these patients. In this review, we analyze available data and results from recently published literature and provide an overview of current recommendations of HCV-therapy regimen in these special patient cohorts. PMID:26251895

  12. AST to Platelet Ratio Index Predicts Mortality in Hospitalized Patients With Hepatitis B-Related Decompensated Cirrhosis.

    PubMed

    Mao, Weilin; Sun, Qinqin; Fan, Jian; Lin, Sha; Ye, Bo

    2016-03-01

    Aspartate aminotransferase to platelet ratio index (APRI) has originally been considered as a noninvasive marker for detecting hepatic fibrosis in patients with chronic hepatitis B and C. APRI has been used for predicting liver-related mortality in patients with chronic hepatitis C virus infection or alcoholic liver disease. However, whether APRI could be useful for predicting mortality in chronic hepatitis B virus (HBV) infection remains unevaluated. This study aims to address this knowledge gap. A total of 193 hospitalized chronic HBV-infected patients (cirrhosis, n = 100; noncirrhosis, n = 93) and 88 healthy subjects were retrospectively enrolled. All patients were followed up for 4 months. Mortality that occurred within 90 days of hospital stay was compared among patients with different APRI. APRI predictive value was evaluated by univariate and multivariate regression embedded in a Cox proportional hazards model. APRI varied significantly in our cohort (range, 0.16-10.00). Elevated APRI was associated with increased severity of liver disease and 3-month mortality in hospitalized patients with HBV-related cirrhosis. Multivariate analysis demonstrated that APRI (odds ratio: 1.456, P < 0.001) and the model for end-stage liver disease score (odds ratio: 1.194, P < 0.001) were 2 independent markers for predicting mortality. APRI is a simple marker that may serve as an additional predictor of 3-month mortality in hospitalized patients with HBV-related decompensated cirrhosis.

  13. AST to Platelet Ratio Index Predicts Mortality in Hospitalized Patients With Hepatitis B-Related Decompensated Cirrhosis

    PubMed Central

    Mao, Weilin; Sun, Qinqin; Fan, Jian; Lin, Sha; Ye, Bo

    2016-01-01

    Abstract Aspartate aminotransferase to platelet ratio index (APRI) has originally been considered as a noninvasive marker for detecting hepatic fibrosis in patients with chronic hepatitis B and C. APRI has been used for predicting liver-related mortality in patients with chronic hepatitis C virus infection or alcoholic liver disease. However, whether APRI could be useful for predicting mortality in chronic hepatitis B virus (HBV) infection remains unevaluated. This study aims to address this knowledge gap. A total of 193 hospitalized chronic HBV-infected patients (cirrhosis, n = 100; noncirrhosis, n = 93) and 88 healthy subjects were retrospectively enrolled. All patients were followed up for 4 months. Mortality that occurred within 90 days of hospital stay was compared among patients with different APRI. APRI predictive value was evaluated by univariate and multivariate regression embedded in a Cox proportional hazards model. APRI varied significantly in our cohort (range, 0.16–10.00). Elevated APRI was associated with increased severity of liver disease and 3-month mortality in hospitalized patients with HBV-related cirrhosis. Multivariate analysis demonstrated that APRI (odds ratio: 1.456, P < 0.001) and the model for end-stage liver disease score (odds ratio: 1.194, P < 0.001) were 2 independent markers for predicting mortality. APRI is a simple marker that may serve as an additional predictor of 3-month mortality in hospitalized patients with HBV-related decompensated cirrhosis. PMID:26945406

  14. Hepatitis C in Special Patient Cohorts: New Opportunities in Decompensated Liver Cirrhosis, End-Stage Renal Disease and Transplant Medicine.

    PubMed

    Hüsing, Anna; Kabar, Iyad; Schmidt, Hartmut H; Heinzow, Hauke S

    2015-01-01

    Worldwide, hepatitis C virus (HCV) is a common infection. Due to new antiviral approaches and the approval of direct-acting antiviral agents (DAA), HCV therapy has become more comfortable. Nevertheless, there are special patient groups, in whom treatment of HCV is still challenging. Due to only few data available, tolerability and efficacy of DAAs in special patient cohorts still remain unclear. Such special patient cohorts comprise HCV in patients with decompensated liver disease (Child-Pugh Class B or C), patients with chronic kidney disease, and patients on waiting lists to renal/liver transplantation or those with HCV recurrence after liver transplantation. HCV infection in these patient cohorts has been shown to be associated with increased morbidity and mortality and may lead to reduced graft survival after transplantation. Successful eradication of HCV results in a better outcome concerning liver-related complications and in a better clinical outcome of these patients. In this review, we analyze available data and results from recently published literature and provide an overview of current recommendations of HCV-therapy regimen in these special patient cohorts. PMID:26251895

  15. Severe Acute Traumatic Mitral Regurgitation, Cardiogenic Shock Secondary to Embolized Polymethylmethracrylate Cement Foreign Body After a Percutaneous Vertebroplasty.

    PubMed

    Elapavaluru, Subbarao; Alhassan, Sulaiman; Khan, Fawad; Khalil, Ramzi; Schuett, Amy; Bailey, Stephen

    2016-03-01

    We report the case of a 61-year-old woman with acute decompensated heart failure secondary to acute traumatic mitral regurgitation, resulting from polymethylmethacrylate cement found in the left ventricle less than 24 hours after fluoroscopic percutaneous vertebroplasty. The patient had a history of ovarian cancer and had undergone treatment for symptomatic osteoporotic compression fractures of the vertebrae (T11, L1, and L3). The patient underwent a successful emergency open-heart operation, mitral valve replacement, closure of an atrial septal defect, and video-assisted removal of the cement foreign body from the left ventricle. The patient was later discharged with a good outcome.

  16. Parametric excitation of whistler waves by HF heater

    NASA Technical Reports Server (NTRS)

    Kuo, S. P.; Lee, M. C.

    1989-01-01

    Possible generation of whistler waves by Tromso HF heater is investigated. It is shown that the HF heater wave can parametrically decay into a whistler wave and a Langmuir wave. Since whistler waves may have a broad range of frequency, the simultaneously excited Langmuir waves can have a much broader frequency bandwidth than those excited by the parametric decay instability.

  17. 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.

  18. [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.

  19. Environmental Hf-Nd isotopic decoupling in World river clays

    NASA Astrophysics Data System (ADS)

    Bayon, Germain; Skonieczny, Charlotte; Delvigne, Camille; Toucanne, Samuel; Bermell, Sylvain; Ponzevera, Emmanuel; André, Luc

    2016-03-01

    The hafnium and neodymium radiogenic isotope systems behave differently during Earth surface processes, causing a wide dispersion of Hf and Nd isotopic compositions in sediments and other sedimentary rocks. The decoupling between Hf and Nd isotopes in sediments is generally attributed to a combination of preferential sorting of zircon during sediment transport and incongruent weathering processes on continents. In this study, we analysed size-fractions of sediment samples collected near the mouth of 53 rivers worldwide to better understand the factors controlling the distribution of Hf and Nd isotopes in sediments. Our results for rivers draining old cratonic areas and volcanic provinces demonstrate that both granite and basalt weathering can lead to significant grain-size dependent Hf isotopic variability. While silt-size fractions mainly plot along the Terrestrial Array, World river clays are systematically shifted towards more radiogenic Hf isotopic compositions, defining together with published data a new Clay Array (εHf = 0.78 ×εNd + 5.23). The Hf-Nd isotope decoupling observed in volcanogenic sediments is best explained by selective alteration of Lu-rich mineral phases (e.g. olivine) and preferential enrichment of resistant unradiogenic minerals, such as spinel and ilmenite, in silt fractions. We also show that the extent to which World river clays deviate from the Clay Array (ΔεHf clay) is not linked to the presence of zircons. Instead, it correlates positively with weathering indices and climatic parameters (temperature, rainfall) of the corresponding drainage basins. Overall, these findings demonstrate that the distribution of Hf-Nd isotopes in clay-size sediments is related to a large extent to weathering conditions on continents, although the precise mechanisms controlling this relationship remain unclear. We finally propose that the Hf-Nd isotope pair proxy could be used in palaeoenvironmental studies to provide semi-quantitative information on

  20. The (178m2)Hf Controversy

    SciTech Connect

    Becker, J A; Gemmell, D S; Schiffer, J P; Wilhelmy, J B

    2003-07-24

    Since its discovery in the 1960's the {sup 178m2}Hf isomer has garnered high attention from both the basic and applied communities in nuclear science. It's combination of high spin (16+), long half life (31 yrs), and high excitation energy (2.446 MeV) offer unique possibilities as an energy storage medium. Interest in the isomer was rekindled beginning in 1999 when a series of publications began to appear from a group (referred to here as the ''Texas collaboration'') primarily based at the University of Texas, Dallas [1]. They reported observations that some of the stored energy could be released (''triggered'') when the isomer was exposed to a fluence of photons in the energy range {approx}10 to {approx}60 keV. The implications of this observation are profound. Even though the claimed cross section for the process was {approx}7 orders of magnitude greater than would be predicted from the known systematics of photon absorption by nuclei in this mass range [2], such a highly efficient method for triggering the isomeric deexcitation immediately suggested applications utilizing the explosive or the controlled gradual energy release from a very compact source. The prospect of such applications has focused considerable interest on realizing the promise that is implicit in the reported observations. However, two experiments performed by a group from ANL/LANL/LLNL at the Advanced Photon Source at Argonne (the ''APS collaboration'') reported negative results for the observation of any photon-triggered deexcitation of the {sup 178m2}Hf isomer [3]. This has led to a continued controversy, where both sides have adamantly defended their observations. At this point an outsider has difficulty determining whether there is indeed a triggering effect that should be pursued energetically with substantial resources, or whether the phenomenon consists of overly optimistic interpretation of data.

  1. Curious case of calciphylaxis leading to acute mitral regurgitation

    PubMed Central

    Gallimore, Grant Gardner; Curtis, Blair; Smith, Andria; Benca, Michael

    2014-01-01

    Calciphylaxis is uncommon and typically seen in patients with end-stage renal disease. It has been defined as a vasculopathic disorder characterised by cutaneous ischaemia and necrosis due to calcification, intimal fibroplasia and thrombosis of pannicular arterioles. We present the case of a 74-year-old woman with chronic kidney disease stage III who developed calciphylaxis leading to mitral valve calcification, chordae tendineae rupture and acute mitral regurgitation. Although an alternative explanation can typically be found for non-uraemic calciphylaxis, her evaluation did not reveal any usual non-uraemic causes including elevated calcium–phosphorus product, hyperparathyroidism, or evidence of connective tissue disease. Her wounds improved with sodium thiosulfate, pamidronate, penicillin and hyperbaric oxygen therapies but she ultimately decompensated with the onset of acute mitral regurgitation attributed to rupture of a previously calcified chordae tendineae. This case highlights an unusual case of calciphylaxis without clear precipitant as well as a novel manifestation of the disease. PMID:24789150

  2. 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).

  3. Acute Bronchitis

    MedlinePlus

    ... tightness. There are two main types of bronchitis: acute and chronic. Most cases of acute bronchitis get better within several days. But your ... that cause colds and the flu often cause acute bronchitis. These viruses spread through the air when ...

  4. Levosimendan beyond inotropy and acute heart failure: Evidence of pleiotropic effects on the heart and other organs: An expert panel position paper.

    PubMed

    Farmakis, Dimitrios; Alvarez, Julian; Gal, Tuvia Ben; Brito, Dulce; Fedele, Francesco; Fonseca, Candida; Gordon, Anthony C; Gotsman, Israel; Grossini, Elena; Guarracino, Fabio; Harjola, Veli-Pekka; Hellman, Yaron; Heunks, Leo; Ivancan, Visnja; Karavidas, Apostolos; Kivikko, Matti; Lomivorotov, Vladimir; Longrois, Dan; Masip, Josep; Metra, Marco; Morelli, Andrea; Nikolaou, Maria; Papp, Zoltán; Parkhomenko, Alexander; Poelzl, Gerhard; Pollesello, Piero; Ravn, Hanne Berg; Rex, Steffen; Riha, Hynek; Ricksten, Sven-Erik; Schwinger, Robert H G; Vrtovec, Bojan; Yilmaz, M Birhan; Zielinska, Marzenna; Parissis, John

    2016-11-01

    Levosimendan is a positive inotrope with vasodilating properties (inodilator) indicated for decompensated heart failure (HF) patients with low cardiac output. Accumulated evidence supports several pleiotropic effects of levosimendan beyond inotropy, the heart and decompensated HF. Those effects are not readily explained by cardiac function enhancement and seem to be related to additional properties of the drug such as anti-inflammatory, anti-oxidative and anti-apoptotic ones. Mechanistic and proof-of-concept studies are still required to clarify the underlying mechanisms involved, while properly designed clinical trials are warranted to translate preclinical or early-phase clinical data into more robust clinical evidence. The present position paper, derived by a panel of 35 experts in the field of cardiology, cardiac anesthesiology, intensive care medicine, cardiac physiology, and cardiovascular pharmacology from 22 European countries, compiles the existing evidence on the pleiotropic effects of levosimendan, identifies potential novel areas of clinical application and defines the corresponding gaps in evidence and the required research efforts to address those gaps.

  5. 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

  6. 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

  7. 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.

  8. 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

  9. Loss of the AE3 Anion Exchanger in a Hypertrophic Cardiomyopathy Model Causes Rapid Decompensation and Heart Failure

    PubMed Central

    Al Moamen, Nabeel J.; Prasad, Vikram; Bodi, Ilona; Miller, Marian L.; Neiman, Michelle L.; Lasko, Valerie M.; Alper, Seth L.; Wieczorek, David F.; Lorenz, John N.; Shull, Gary E.

    2010-01-01

    The AE3 Cl−/HCO3− exchanger is abundantly expressed in the sarcolemma of cardiomyocytes, where it mediates Cl−-uptake and HCO3−-extrusion. Inhibition of AE3-mediated Cl−/HCO3− exchange has been suggested to protect against cardiac hypertrophy; however, other studies indicate that AE3 might be necessary for optimal cardiac function. To test these hypotheses we crossed AE3-null mice, which appear phenotypically normal, with a hypertrophic cardiomyopathy mouse model carrying a Glu180Gly mutation in α–tropomyosin (TM180). Loss of AE3 had no effect on hypertrophy; however, survival of TM180/AE3 double mutants was sharply reduced compared with TM180 single mutants. Analysis of cardiac performance revealed impaired cardiac function in TM180 and TM180/AE3 mutants. TM180/AE3 double mutants were more severely affected and exhibited little response to β-adrenergic stimulation, a likely consequence of their more rapid progression to heart failure. Increased expression of calmodulin-dependent kinase II and protein phosphatase 1 and differences in methylation and localization of protein phosphatase 2A were observed, but were similar in single and double mutants. Phosphorylation of phospholamban on Ser16 was sharply increased in both single and double mutants relative to wild-type hearts under basal conditions, leading to reduced reserve capacity for β-adrenergic stimulation of phospholamban phosphorylation. Imaging analysis of isolated myocytes revealed reductions in amplitude and decay of Ca2+ transients in both mutants, with greater reductions in TM180/AE3 mutants, consistent with the greater severity of their heart failure phenotype. Thus, in the TM180 cardiomyopathy model, loss of AE3 had no apparent anti-hypertrophic effect and led to more rapid decompensation and heart failure. PMID:21056571

  10. Stratospheric HF and HCl observations /15 June 1981/

    NASA Technical Reports Server (NTRS)

    Traub, W. A.; Chance, K. V.

    1981-01-01

    Balloon measurements of the stratospheric HF/HCl ratio are reported. Seven far-infrared rotational lines of HF and HCl were observed at elevation angles of 25, 18 and 8 deg by a far-infrared Fourier-transform spectrometer on board a balloon platform at 28.5 km. Analysis of line intensities yields an average HF/HCl ratio of 0.18 + or - 0.02 at an effective altitude of 33 km, with a water vapor mixing ratio of about 4 ppmv. Results are noted to be in reasonable agreement with the calculated profile of Sze and Ko (1981) with 4.5 ppmv H2O.

  11. Acute cardio-renal syndrome: progression from congestive heart failure to congestive kidney failure.

    PubMed

    Wencker, Detlef

    2007-09-01

    Over the past few years, acute worsening of renal function has emerged as a powerful and independent predictor of adverse cardiac outcomes among patients hospitalized with acute heart failure exacerbation. This phenomenon has been recently termed acute cardio-renal syndrome. Acute cardio-renal syndrome is not uncommon, affecting roughly one third of acute decompensated heart failure patients. The mechanism of acute cardio-renal syndrome is poorly understood and difficult to elucidate in light of the complex and multifactorial comorbidities associated with acute heart failure syndrome. Acute cardio-renal syndrome is commonly explained by hypoperfusion of the kidney with intravascular volume depletion, hypotension and low flow state ("pre-renal syndrome"). This perception, however, is challenged by the actual hemodynamics present during acute cardio-renal syndrome characterized by hypervolemia, normal cardiac output, and elevated filling pressures of the systemic and venous circulation. This review discusses the long-standing and unnoticed evidence in support of the notion that right-sided failure with raised filling pressure of the renal vein by itself can indeed lead to acute worsening renal function with oliguria, azotemia, and reduced glomerular filtration rate.

  12. Pathophysiology of cardiorenal syndrome in decompensated heart failure: role of lung-right heart-kidney interaction.

    PubMed

    Guazzi, M; Gatto, P; Giusti, G; Pizzamiglio, F; Previtali, I; Vignati, C; Arena, R

    2013-11-30

    Cardiorenal syndrome (CRS) is defined as an interaction of cardiac disease with renal dysfunction that leads to diuretic resistance and renal function worsening, mainly with heart failure (HF) exacerbation. Hemodynamic variables linking heart and kidney are renal blood flow (cardiac output) and perfusion pressure, i.e., the aortic - renal venous pressure gradient. CRS has traditionally been interpreted as related to defective renal perfusion and arterial underfilling and, more recently, to elevation in central venous pressure transmitted back to renal veins. Our suggestion is that in a setting where aortic pressure is generally low, due to heart dysfunction and to vasodrepressive therapy, the elevated central venous pressure (CVP) contributes to lower the renal perfusion pressure below the threshold of kidney autoregulation (≤80mm Hg) and causes renal perfusion to become directly pressure dependent. This condition is associated with high neurohumoral activation and preglomerular vasoconstriction that may preserve pressure, but may decrease filtration fraction and glomerular filtration rate and enhance proximal tubular sodium absorption. Thus, congestion worsens and drives the vicious cycle of further sodium retention and HF exacerbation. Lowering CVP by targeting the lung-right heart interaction that sustains elevated CVP seems to be a more rational approach rather than reducing intravascular volume. This interaction is crucial and consists of a cascade with stepwise development of pulmonary post-capillary hypertension, precapillary arteriolar hypertone, right ventricular overload and enlargement with tricuspid incompetence and interference with left ventricular filling (interdependence). The resultant CVP rise is transmitted to the renal veins, eventually drives CRS and leads to a positive feedback loop evolving towards HF refractoriness.

  13. 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.

  14. 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.

  15. 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 .

  16. 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.

  17. Amorphous powders of Al-Hf prepared by mechanical alloying

    SciTech Connect

    Schwarz, R.B.; Hannigan, J.W.; Sheinberg, H.; Tiainen, T.

    1988-01-01

    We synthesized amorphous Al/sub 50/Hf/sub 50/ alloy powder by mechanically alloying an equimolar mixture of crystalline powders of Al and Hf using hexane as a dispersant. We characterized the powder as a function of mechanical-alloying time by scanning electron microscopy, x-ray diffraction, and differential scanning calorimetry. Amorphous Al/sub 50/Hf/sub 50/ powder heated at 10 K s/sup /minus/1/ crystallizes polymorphously at 1003 K into orthorhombic AlHf (CrB-type structure). During mechanical alloying, some hexane decomposes and hydrogen and carbon are incorporated into the amorphous alloy powder. The hydrogen can be removed by annealing the powder by hot pressing at a temperature approximately 30 K below the crystallization temperature. The amorphous compacts have a diamond pyramidal hardness of 1025 DPH. 24 refs., 7 figs., 1 tab.

  18. 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.

  19. 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

  20. Phase control of HF chemical lasers for coherent optical recombination.

    PubMed

    Wang, C P; Smith, P L

    1979-05-01

    A servo system for phase-locking two HF chemical lasers has been designed and simulated. A steady-state phase error is achieved that is adequate for coherent optical recombination. The results are based on the measured frequency drift of a small HF chemical laser and the measured frequency response of a piezoelectric transducer (PZT) mirror driver. A major innovation is the use of rate feedback with a laser Doppler sensor to extend the useful frequency response of the PZT driver.

  1. Few-layer HfS2 transistors

    PubMed Central

    Kanazawa, Toru; Amemiya, Tomohiro; Ishikawa, Atsushi; Upadhyaya, Vikrant; Tsuruta, Kenji; Tanaka, Takuo; Miyamoto, Yasuyuki

    2016-01-01

    HfS2 is the novel transition metal dichalcogenide, which has not been experimentally investigated as the material for electron devices. As per the theoretical calculations, HfS2 has the potential for well-balanced mobility (1,800 cm2/V·s) and bandgap (1.2 eV) and hence it can be a good candidate for realizing low-power devices. In this paper, the fundamental properties of few-layer HfS2 flakes were experimentally evaluated. Micromechanical exfoliation using scotch tape extracted atomically thin HfS2 flakes with varying colour contrasts associated with the number of layers and resonant Raman peaks. We demonstrated the I-V characteristics of the back-gated few-layer (3.8 nm) HfS2 transistor with the robust current saturation. The on/off ratio was more than 104 and the maximum drain current of 0.2 μA/μm was observed. Moreover, using the electric double-layer gate structure with LiClO4:PEO electrolyte, the drain current of the HfS2 transistor significantly increased to 0.75 mA/μm and the mobility was estimated to be 45 cm2/V·s at least. This improved current seemed to indicate superior intrinsic properties of HfS2. These results provides the basic information for the experimental researches of electron devices based on HfS2. PMID:26926098

  2. Few-layer HfS2 transistors

    NASA Astrophysics Data System (ADS)

    Kanazawa, Toru; Amemiya, Tomohiro; Ishikawa, Atsushi; Upadhyaya, Vikrant; Tsuruta, Kenji; Tanaka, Takuo; Miyamoto, Yasuyuki

    2016-03-01

    HfS2 is the novel transition metal dichalcogenide, which has not been experimentally investigated as the material for electron devices. As per the theoretical calculations, HfS2 has the potential for well-balanced mobility (1,800 cm2/V·s) and bandgap (1.2 eV) and hence it can be a good candidate for realizing low-power devices. In this paper, the fundamental properties of few-layer HfS2 flakes were experimentally evaluated. Micromechanical exfoliation using scotch tape extracted atomically thin HfS2 flakes with varying colour contrasts associated with the number of layers and resonant Raman peaks. We demonstrated the I-V characteristics of the back-gated few-layer (3.8 nm) HfS2 transistor with the robust current saturation. The on/off ratio was more than 104 and the maximum drain current of 0.2 μA/μm was observed. Moreover, using the electric double-layer gate structure with LiClO4:PEO electrolyte, the drain current of the HfS2 transistor significantly increased to 0.75 mA/μm and the mobility was estimated to be 45 cm2/V·s at least. This improved current seemed to indicate superior intrinsic properties of HfS2. These results provides the basic information for the experimental researches of electron devices based on HfS2.

  3. Synthesis of freestanding HfO2 nanostructures

    PubMed Central

    2011-01-01

    Two new methods for synthesizing nanostructured HfO2 have been developed. The first method entails exposing HfTe2 powders to air. This simple process resulted in the formation of nanometer scale crystallites of HfO2. The second method involved a two-step heating process by which macroscopic, freestanding nanosheets of HfO2 were formed as a byproduct during the synthesis of HfTe2. These highly two-dimensional sheets had side lengths measuring up to several millimeters and were stable enough to be manipulated with tweezers and other instruments. The thickness of the sheets ranged from a few to a few hundred nanometers. The thinnest sheets appeared transparent when viewed in a scanning electron microscope. It was found that the presence of Mn enhanced the formation of HfO2 by exposure to ambient conditions and was necessary for the formation of the large scale nanosheets. These results present new routes to create freestanding nanostructured hafnium dioxide. PACS: 81.07.-b, 61.46.Hk, 68.37.Hk. PMID:21711786

  4. 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.

  5. 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.

  6. [Treatment of acute myocardial infarction with betareceptor blocking agents. I. Hemodynamic effects of Propranolol in combination with digitalis (author's transl)].

    PubMed

    Oeff, M; Lehmann, H U; Witt, E; Hochrein, H

    1981-06-01

    In the acute stage of transmural myocardial infarction, 22 patients ranging in age from 34 to 76 (mean 61.6) were given propranolol- because of its alleged myocardium-protecting properties - intravenously at a dosage of 0.03 to 0.1 mg/kg body weight under conditions of continuous hemodynamic control. Subsequently, the influence of digoxin, administered i. v. at a dosage of 0.01 my/kg body weight, on the negative-inotropic propranolol effects was examined. A hemodynamic comparison was made of the effects of propranolol before and after digitalis administration. In patients with compensated cardiac function (group 1, 16 patients), the propranolol-induced drop in the left ventricular stroke-work-index and rise in the left-ventricular filling pressure was completely compensated again by digitalis. The frequency-decreasing propranolol effect was nor influenced by digitalis. In patients with cardiac decompensation (group 2, 6 patients) digitalis only led to a renewed compensation of the left-ventricular stroke-work-index, the rise of the left-ventricular filling pressure remained unaffected. It follows from that, in cases of myocardial infarction without cardial decompensation, propranolol requires concomitant digitalisation. In cases of already existent myocardial insufficiency, propranolol can produce an unfavorable increase of the decompensation signs. PMID:7257499

  7. Challenging the assumptions of Lu-Hf dating in spinel-peridotites

    NASA Astrophysics Data System (ADS)

    Byerly, B. L.; Lassiter, J. C.

    2013-12-01

    Lu-Hf 'pseudoisochrons' using peridotite-derived clinopyroxene separates are commonly used to constrain timing of melt depletion and lithosphere formation. However, cpx-based pseudoisochrons are only valid if 1) almost all Hf and Lu is hosted in the cpx, or 2) the system is below the mineral closure temperature. We tested these assumptions by examining Lu and Hf partitioning and Hf-isotope variations in cpx, opx, and bulk peridotite in xenoliths from the eastern Colorado Plateau and Rio Grande Rift. The samples primarily derive from Proterozoic SCLM, span a range of fertility (spinel Cr# range from 0.1-0.5), and have equilibration temperatures ranging from 950-1050°C, similar to temperatures reported for other xenoliths utilized in Lu-Hf isotope studies. Cpx have Hf and Lu concentrations ranging from 40-1000 ppb and 80-290 ppb, respectively. Opx have much lower Hf and Lu concentrations (5-60 ppb and 21-51 ppb). Concentrations of Lu, Hf, and other trace elements are well correlated between cpx and opx, indicating mineral equilibrium. DLucpx/opx and DHfcpx/opx range from 3.5-6.1 and 7.0-20, and are negatively correlated with cpx MgO content and other indices of peridotite fertility (e.g., spinel Cr#). Our results agree with (and extend the compositional range of) partition coefficients estimated following the formulation of [1]. The fraction of Lu and Hf hosted in opx increases in highly refractory samples. Although Lu/Hf in cpx is close to WR Lu/Hf in fertile samples, in refractory samples it is much lower. Hf isotopes in cpx are well correlated with cpx Lu/Hf (r2 = 0.998) and yield a pseudoisochron age of ~1.6 Ga (initial ɛHf of +30). Opx have systematically higher Lu/Hf than cpx, but in most samples have identical Hf isotopes. Some opx and WR have lower 176Hf/177Hf, similar to the host magma, likely reflecting melt contamination. The identical Hf isotopes in cpx and opx indicate that xenoliths evolved above the Lu-Hf closure temperature. Therefore, cpx (and opx

  8. Early Management of Patients With Acute Heart Failure: State of the Art and Future Directions

    PubMed Central

    Collins, Sean P.; Storrow, Alan B.; Levy, Phillip D.; Albert, Nancy; Butler, Javed; Ezekowitz, Justin A.; Felker, G. Michael; Fermann, Gregory J.; Fonarow, Gregg C.; Givertz, Michael M.; Hiestand, Brian; Hollander, Judd E.; Lanfear, David E.; Pang, Peter S.; Peacock, W. Frank; Sawyer, Douglas B.; Teerlink, John R.; Lenihan, Daniel J.

    2015-01-01

    Heart failure (HF) afflicts nearly 6 million Americans, resulting in 1 million emergency department (ED) visits and over 1 million annual hospital discharges. The majority of inpatient admissions originate in the ED; thus, it is crucial that emergency physicians and other providers involved in early management understand the latest developments in diagnostic testing, therapeutics, and alternatives to hospitalization. This article discusses contemporary ED management as well as the necessary next steps for ED-based acute HF research. PMID:25423908

  9. 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.

  10. Treatment of Wilson's disease with zinc. XVIII. Initial treatment of the hepatic decompensation presentation with trientine and zinc.

    PubMed

    Askari, Fred K; Greenson, Joel; Dick, Robert D; Johnson, Virginia D; Brewer, George J

    2003-12-01

    We have treated 9 patients who presented with hepatic decompensation resulting from Wilson's disease with a combination of trientine and zinc, generally for at least 4 months, followed by transition to zinc maintenance therapy. All of these patients had hypoalbuminemia, all but 1 had hyperbilirubinemia, and 7 had ascites. All of these patients would have been candidates for liver transplantation on the basis of their initial Child-Turcotte-Pugh (CTP) scores. The minimal listing criteria for transplant candidates is a score greater than 7. Eight of the 9 patients had demonstrated a CTP score of 10 or higher. The other scoring system that has been used in Wilson's disease to determine need for transplantation is the prognostic index of Nazer, in which a score over 6 indicates that the patient is unlikely to survive without a transplant if treated with penicillamine. Two of our patients had Nazer scores higher than 6. With our medical therapy, all 9 of these patients have recovered normal liver function as reflected by normalization of their CTP scores to 5. Because of coexisting neurologic disease, 1 of our 9 patients was initiated on a neurologic protocol and by chance randomized to receive tetrathiomolybdate (TM) and zinc after 2 weeks of trientine/zinc treatment. This patient's liver function recovered much more rapidly than did that of the other 8 patients, all of whom were treated with trientine/zinc, suggesting that TM therapy offers a further advantage. In summary, we were able to take 9 patients who presented with liver failure -8 of whom had CTP scores indicating a potential need for liver transplantation and 2 of whom had Nazer prognostic scores indicating that they were not likely to survive if treated only with penicillamine - and treat them medically, with recovery in all 9. We believe the trientine/zinc combination therapy should be the standard for initial treatment of liver failure in Wilson's disease because its efficacy is equal or slightly superior

  11. 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

  12. 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.

  13. Influence of heart failure on the prognosis of patients with acute myocardial infarction in southwestern China

    PubMed Central

    DENG, FUXUE; XIA, YONG; FU, MICHAEL; HU, YUNFENG; JIA, FANG; RAHARDJO, YEFFRY; DUAN, YINGYI; HE, LINJING; CHANG, JING

    2016-01-01

    The impact of heart failure (HF) on acute myocardial infarction (AMI) in patients from southwestern China remains unclear. The present study aimed to compare in-hospital cardiovascular events, mortality and clinical therapies in AMI patients with or without HF in southwestern China. In total, 591 patients with AMI hospitalized between February 2009 and December 2012 were examined; those with a history of HF were excluded. The patients were divided into four groups according to AMI type (ST-elevated or non-ST-elevated AMI) and the presence of HF during hospitalization. Clinical characteristics, in-hospital cardiovascular events, mortality, coronary angiography and treatment were compared. Clinical therapies, specifically evidence-based drug use were analyzed in patients with HF during hospitalization, including angiotensin converting enzyme inhibitors (ACEIs) and β-blockers (BBs). AMI patients with HF had a higher frequency of co-morbidities, lower left ventricular ejection fraction, longer length of hospital stay and a greater risk of in-hospital mortality compared with AMI patients without HF. AMI patients with HF were less likely to be examined by cardiac angiography or treated with reperfusion therapy or recommended medications. AMI patients with HF co-treated with ACEIs and BBs had a significantly higher survival rate (94.4 vs. 67.5%; P<0.001) compared with untreated patients or patients treated with either ACEIs or BBs alone. Logistic regression analysis revealed that HF and cardiogenic shock in patients with AMI were the strongest predictors of in-hospital mortality. AMI patients with HF were at a higher risk of adverse outcomes. Cardiac angiography and timely standard recommended medications were associated with improved clinical outcomes. PMID:27284294

  14. Hf-Zr anomalies in clinopyroxene from mantle xenoliths from France and Poland: implications for Lu-Hf dating of spinel peridotite lithospheric mantle

    NASA Astrophysics Data System (ADS)

    Downes, Hilary; de Vries, Caja; Wittig, Nadine

    2014-09-01

    Clinopyroxenes in some fresh anhydrous spinel peridotite mantle xenoliths from the northern Massif Central (France) and Lower Silesia (Poland), analysed for a range of incompatible trace elements by laser ablation inductively coupled plasma mass spectrometry, show unusually strong negative anomalies in Hf and Zr relative to adjacent elements Sm and Nd, on primitive mantle-normalised diagrams. Similar Zr-Hf anomalies have only rarely been reported from clinopyroxene in spinel peridotite mantle xenoliths worldwide, and most are not as strong as the examples reported here. Low Hf contents give rise to a wide range of Lu/Hf ratios, which over geological time would result in highly radiogenic ɛHf values, decoupling them from ɛNd ratios. The high 176Lu/177Hf could in theory produce an isochronous relationship with 176Hf/177Hf over time; an errorchron is shown by clinopyroxene from mantle xenoliths from the northern Massif Central. However, in a review of the literature, we show that most mantle spinel peridotites do not show such high Lu/Hf ratios in their constituent clinopyroxenes, because they lack the distinctive Zr-Hf anomaly, and this limits the usefulness of the application of the Lu-Hf system of dating to garnet-free mantle rocks. Nevertheless, some mantle xenoliths from Poland or the Czech Republic may be amenable to Hf-isotope dating in the future.

  15. Hf-Zr anomalies in clinopyroxene from mantle xenoliths from France and Poland: implications for Lu-Hf dating of spinel peridotite lithospheric mantle

    NASA Astrophysics Data System (ADS)

    Downes, Hilary; de Vries, Caja; Wittig, Nadine

    2015-01-01

    Clinopyroxenes in some fresh anhydrous spinel peridotite mantle xenoliths from the northern Massif Central (France) and Lower Silesia (Poland), analysed for a range of incompatible trace elements by laser ablation inductively coupled plasma mass spectrometry, show unusually strong negative anomalies in Hf and Zr relative to adjacent elements Sm and Nd, on primitive mantle-normalised diagrams. Similar Zr-Hf anomalies have only rarely been reported from clinopyroxene in spinel peridotite mantle xenoliths worldwide, and most are not as strong as the examples reported here. Low Hf contents give rise to a wide range of Lu/Hf ratios, which over geological time would result in highly radiogenic ɛHf values, decoupling them from ɛNd ratios. The high 176Lu/177Hf could in theory produce an isochronous relationship with 176Hf/177Hf over time; an errorchron is shown by clinopyroxene from mantle xenoliths from the northern Massif Central. However, in a review of the literature, we show that most mantle spinel peridotites do not show such high Lu/Hf ratios in their constituent clinopyroxenes, because they lack the distinctive Zr-Hf anomaly, and this limits the usefulness of the application of the Lu-Hf system of dating to garnet-free mantle rocks. Nevertheless, some mantle xenoliths from Poland or the Czech Republic may be amenable to Hf-isotope dating in the future.

  16. What Is Decompensated Cirrhosis?

    MedlinePlus

    ... Minority Veterans Plain Language Surviving Spouses & Dependents Adaptive Sports Program ADMINISTRATION Veterans Health Administration Veterans Benefits Administration National Cemetery Administration U.S. Department of Veterans ...

  17. Latitudinal distributions and temporal changes of stratospheric HCl and HF

    NASA Technical Reports Server (NTRS)

    Mankin, W. G.; Coffey, M. T.

    1983-01-01

    Hydrogen chloride and hydrogen fluoride are important sinks in the stratosphere for free halogens. The major sources of chlorine and fluorine in the stratosphere are anthropogenic; therefore, a measurement of HCl and HF gives information about the magnitude of anthropogenic effects on stratospheric chemistry and may give some information about the stratospheric hydroxyl concentration as well. The total column amount of HCl and HF above 12 km has been determined by measuring infrared absorption spectra with a high-resolution Fourier transform spectrometer flown on a jet aircraft. The HCl column varies from 0.7 x 10 to the 15th molecules/ sq cm near the equator to 2.7 x 10 to the 15th molecules/sq cm at 70 N; the HF column is about a factor of 5 lower. The HCl:HF ratio is almost independent of latitude, and neither constituent shows substantial seasonal or diurnal variation. At mid-latitudes, the data from 1978 to 1982 show an annual increase of 5 percent per year for HCl and 12 percent per year for HF.

  18. 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.

  19. [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.

  20. 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.

  1. 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.

  2. 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

  3. 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.

  4. 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

  5. Concerted hydrogen atom exchange between three HF molecules

    NASA Technical Reports Server (NTRS)

    Komornicki, Andrew; Dixon, David A.; Taylor, Peter R.

    1992-01-01

    The termolecular reaction involving concerted hydrogen-atom exchange between three HF molecules was investigated with particular attention given to the effects of correlation at the various stationary points along the reaction. Using large segmented Gaussian basis sets to locate the (HF)3 stationary points at the SCF level, the geometries of the stable hydrogen-bonded trimer, which is of C(3h) symmetry, were located, together with the transition state for hydrogen exchange, which is of D(3h) symmetry. Then, using a large atomic natural orbital basis and correlating all valence electrons, the energetics of the exchange reaction were evaluated at the correlated level.

  6. 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.

  7. NT-proBNP: A Guide to Improve the Management of Patients with Heart Failure

    PubMed Central

    Masson, Serge

    2013-01-01

    N-terminal prohormone of brain natriuretic peptide (NT-proBNP) is a versatile biomarker, that has been extensively studied in large cohorts of individuals in the general population, in subjects at risk for developing left ventricular dysfunction and cardiovascular events, and in patients with chronic or acutely decompensated heart failure (HF). In this paper, the pros and cons of using natriuretic peptide testing to manage patients with HF are presented and discussed over 3 broad areas: (1) dyspnea triage in the emergency room, (2) natriuretic peptide-guided treatment of chronic HF, and (3) management of patients with HF in primary care and nursing homes.

  8. 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.

  9. 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

  10. 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

  11. Infrared overtone spectroscopy of hydrogen fluoride van der Waals complexes at upsilon (HF) = 3

    NASA Astrophysics Data System (ADS)

    Tsang, Susy Ngan Ping

    1998-11-01

    The dependence of weak intermolecular forces on valence bond excitations is investigated by the spectroscopy and vibrational predissociation dynamics of four hydrogen fluoride van der Waals complexes, N2HF, (HF)2, Ar2HF and Ar3HF, at the second overtone vibrational excitation of the hydrogen bonded HF intramolecular stretch, v HF=3. The formation and detection of these weakly bound complexes are achieved by the unique combination of slit supersonic jet expansion and intracavity Ti:sapphire laser-induced fluorescence. For the four complexes studied, an increase in the red- shift as a function of v HF was observed in the hydrogen bonded HF valence stretch as a result of the strengthening of the hydrogen bond. In addition, changes in the anisotropies of the intermolecular potentials of these weakly bound systems are in accord with those observed in the prototypical studies of ArHF at v HF=3 in this laboratory. However, the van der Waals soft modes have only been completely characterized for N2HF at v HF=3. Moreover, the frequencies of these intermolecular modes were experimentally determined for the first time in the N2HF complex. Of major interest in the N2HF studies is the intermolecular state dependence of the vibrational predissociation in this complex at v HF=3. Intermolecular state dependent vibrational predissociation dynamics is also observed in the (HF)2 studies. In order to further understand the complex internal dynamics in N2HF, ab initio calculations for a highly accurate four-dimensional potential energy surface using the symmetry adapted perturbation theory (SAPT) method were performed at v HF=0 and at v HF=3. A preliminary analysis of the ab initio data for both vibrational states and bound state calculations for the ground state potential energy surface are presented. The work on the Ar2HF and Ar3HF clusters tests the accuracy of pairwise additive intermolecular potentials for these two systems at v HF=3. In particular, the data obtained on these

  12. Preliminary data on immunogenicity, safety and tolerability of trivalent inactivated influenza vaccine in children with inborn errors of metabolism at risk of decompensation.

    PubMed

    Esposito, Susanna; Salvini, Filippo; Menni, Francesca; Scala, Alessia; Salvatici, Elisabetta; Manzoni, Francesca; Riva, Enrica; Giovannini, Marcello; Principi, Nicola

    2013-10-25

    In order to evaluate the immunogenicity, safety and tolerability of influenza vaccination in children with inborn errors of metabolism (IEMs), we enrolled 20 patients with IEMs at risk of decompensation (14 males; mean age±SD, 8.5±3.9years) and 20 healthy age- and gender-matched controls. Four weeks after vaccination, seroconversion rates were 75-85% and seroprotection rates 85-95%, with high geometric mean titers (GMTs) of all three influenza antigen strains in both groups. Three months after vaccination, most of the subjects remained seroconverted with high seroprotection rates and high GMTs for all the three influenza strains. Safety and tolerability were also very good, with no differences between the groups.

  13. Pathophysiology and clinical evaluation of acute heart failure.

    PubMed

    Mentz, Robert J; O'Connor, Christopher M

    2016-01-01

    Acute heart failure (AHF) is a complex syndrome characterized by worsening heart failure (HF) symptoms that requires escalation of therapy. Intrinsic cardiac abnormalities and comorbid conditions, including lung and renal disease, and sleep-disordered breathing, can contribute to the development of AHF. In this Review, we summarize and discuss the literature on the clinical evaluation and underlying pathophysiology of AHF. Important features of AHF evaluation include identification of precipitating factors to the disease, and assessment of circulatory-renal limitations associated with use of HF medications, prior HF hospitalizations, congestion and perfusion profiles, and end-organ dysfunction. The pathophysiological contributions of endothelial dysfunction, neurohormonal activation, venous congestion, and myocardial injury to the development of AHF are also discussed. These potential causative mechanisms provide a framework for clinicians to evaluate and manage patients with AHF and highlight possible future targets for therapies designed to improve clinical outcomes.

  14. Early management of patients with acute heart failure: state of the art and future directions--a consensus document from the SAEM/HFSA acute heart failure working group.

    PubMed

    Collins, Sean P; Storrow, Alan B; Levy, Phillip D; Albert, Nancy; Butler, Javed; Ezekowitz, Justin A; Felker, G Michael; Fermann, Gregory J; Fonarow, Gregg C; Givertz, Michael M; Hiestand, Brian; Hollander, Judd E; Lanfear, David E; Pang, Peter S; Peacock, W Frank; Sawyer, Douglas B; Teerlink, John R; Lenihan, Daniel J

    2015-01-01

    Heart failure (HF) afflicts nearly 6 million Americans, resulting in 1 million emergency department (ED) visits and over 1 million annual hospital discharges. The majority of inpatient admissions originate in the ED; thus, it is crucial that emergency physicians and other providers involved in early management understand the latest developments in diagnostic testing, therapeutics, and alternatives to hospitalization. This article discusses contemporary ED management as well as the necessary next steps for ED-based acute HF research.

  15. Photon scattering experiments off 176Hf and the systematics of low-lying dipole modes in the stable even-even Hf isotopes 176,178,180Hf

    NASA Astrophysics Data System (ADS)

    Scheck, M.; Belic, D.; von Brentano, P.; Carroll, J. J.; Fransen, C.; Gade, A.; von Garrel, H.; Kneissl, U.; Kohstall, C.; Linnemann, A.; Pietralla, N.; Pitz, H. H.; Stedile, F.; Toman, R.; Werner, V.

    2003-06-01

    The low-lying dipole strength distribution in the rare isotope 176Hf was studied in nuclear resonance fluorescence experiments performed at the Stuttgart Dynamitron facility using bremsstrahlung beams with end- point energies of 4.1 and 2.4 MeV. In total, about 55 excited spin-1 states, unknown so far, were observed in the excitation energy range up to 4 MeV. Detailed spectroscopic information has been obtained on excitation energies, spins, decay widths, decay branchings, and transition probabilities. Ascribing a positive parity to all observed K=1 states, the detected total B(M1)↑ strength in the energy range of the scissors mode amounts to 2.56(6) μ2N, nearly as much as for well-deformed midshell rare-earth nuclei. The total strength is higher than in the heavier Hf isotopes 178,180Hf, but fits well into the systematics. The observed low-lying ΔK=0 transitions (with probable E1 character) lie in the energy range around 2 MeV, as expected from the systematics. The excitation probabilities correspond to values which are characteristic for nuclei in the transitional region from deformed rotors to more γ-soft nuclei.

  16. Quantitative fibrosis estimation by image analysis predicts development of decompensation, composite events and defines event-free survival in chronic hepatitis B patients.

    PubMed

    Bihari, Chhagan; Rastogi, Archana; Sen, Bijoya; Bhadoria, Ajeet Singh; Maiwall, Rakhi; Sarin, Shiv K

    2016-09-01

    The extent of fibrosis is a major determinant of the clinical outcome in patients with chronic liver diseases. We undertook this study to explore the degree of fibrosis in baseline liver biopsies to predict clinical outcomes in chronic hepatitis B (CHB) patients. Fibrosis quantification was done by image analysis on Masson's trichrome-stained sections and correlated with clinical and biochemical parameters, liver stiffness and hepatic vein pressure gradient (n = 96). Follow-up information collected related to clinical outcome. A total of 964 cases was analyzed. Median quantitative fibrosis (QF) was 3.7% (interquartile range, 1.6%-9.7%) with substantial variation in various stages. Median QF was F0, 1% (0.7%-1.65%); F1, 3.03% (2.07%-4.0%); F2, 7.1% (5.6%-8.7%); F3, 12.7% (10.15%-16.7%); F4, 26.9% (20.3%-36.4%). QF positively correlated with METAVIR staging, liver stiffness measurement, and hepatic vein pressure gradient. Eighty-nine cases developed liver-related events: decompensation, hepatocellular carcinoma, liver transplantation and death. Cox regression analysis after adjusting for METAVIR staging-QF, albumin, and AST for composite events; QF and albumin for decompensation; and only QF for hepatocellular carcinoma-were found to be significant predictors of clinical outcomes. QF categorized into five stages: QF1, 0%-5%; QF2, 5.1%-10%; QF3, 10.1%-15%; QF4, 15.1%-20%; QF5, >20.1%. In patients with advanced stages of QF, probability of event-free survival found to be low. Quantitative fibrosis in baseline liver biopsy predicts progression of the disease and disease outcome in CHB patients. QF defines the probability of event-free survival in CHB cases.

  17. Processing and crystallographic structure of non-equilibrium Si-doped HfO{sub 2}

    SciTech Connect

    Hou, Dong; Fancher, Chris M.; Esteves, Giovanni; Jones, Jacob L.; Zhao, Lili

    2015-06-28

    Si-doped HfO{sub 2} was confirmed to exist as a non-equilibrium state. The crystallographic structures of Si-doped HfO{sub 2} were studied using high-resolution synchrotron X-ray diffraction and the Rietveld refinement method. Incorporation of Si into HfO{sub 2} and diffusion of Si out of (Hf,Si)O{sub 2} were determined as a function of calcination temperature. Higher thermal energy input at elevated calcination temperatures resulted in the formation of HfSiO{sub 4}, which is the expected major secondary phase in Si-doped HfO{sub 2}. The effect of SiO{sub 2} particle size (nano- and micron-sized) on the formation of Si-doped HfO{sub 2} was also determined. Nano-crystalline SiO{sub 2} was found to incorporate into HfO{sub 2} more readily.

  18. 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.

  19. Exploring space plasmas - The WISP/HF experiment

    SciTech Connect

    James, H.G.; Darlington, T.R.; Hersom, C.H.; Gruno, R.S.; Gore, J.V.

    1987-02-01

    WISP/HF is the high-frequency part of the collaborative U.S.-Canada investigation, Waves in Space Plasmas. Instrumentation is being developed that will be flown on NASA's Space Shuttle starting with the Space Plasma Lab missions in the 1990s. Using a high-inclination orbit at heights near the maximum density of the ionospheric F region, active experiments will be carried out on antennas, electromagnetic and electrostatic wave propagation, problems in linear and nonlinear plasma physics, large-scale ionospheric structures, ionospheric irregularities, and the interaction of charged-particle beams with the ionospheric plasma. The WISP/HF equipment will generate, receive, and process signals in the 0.1-to 30-MHz range. The Orbiter-based transmitter will have variable pulse-power levels up to 0.5 kW and will use a dipole of variable length up to 300 m tip-to-tip. WISP/HF receivers will be located both on the Orbiter and on a subsatellite. A high level of operational flexibility in the WISP/HF instrument design has been achieved through programmable digital control. The design also permits human control of experiments, both from the Orbiter and from the ground.

  20. Single source noise reduction of received HF audio: experimental study

    NASA Astrophysics Data System (ADS)

    Campbell, Eric C.; Alva, Carlos O.

    2014-05-01

    This paper visits the application of single-source noise reduction on received audio over a HF channel. The noise reduction algorithm is typically used in vocoder noise processing at the transmitter before encoding. This study presents the results of the algorithm effects by objectively measuring audio quality through the use of industry standard PESQ analysis.

  1. A Coupled Ionosphere-Raytrace Model for Artificial HF Heating

    NASA Astrophysics Data System (ADS)

    Zawdie, K.; Huba, J. D.; Drob, D. P.; Bernhardt, P. A.

    2015-12-01

    The first self-consistent 3D model of artificial HF ionospheric heating has been developed. The model combines the first principles ionosphere model SAMI3/ESF and the ray trace code MoJo-15. The location of HF heating is calculated by simulating the ray path through the ionosphere and determining the average heating location. This new model has been used to successfully simulate the snapback effect discovered in a Arecibo HF heating experiment described by Bernhardt et al. [1988]. The simulations provide new insight into the physical mechanism for snapback. As Bernhardt et al. [1988] hypothesized, the heater wave is refracted by the density cavity, thus causing the location of heating to drift in longitude. The cause of snapback, however, is not that the ray snaps back to its original configuration once the density cavity has convected out of range. Instead, the density cavity convects into the path of the refracted ray such that only a small portion of the ray near the original heating location is above the threshold for HF heating. The heating location thus suddenly snaps back to the original location but the ray itself is still refracted in longitude.

  2. 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

  3. HF wire antennas over real ground: Computer simulation and measurement

    NASA Astrophysics Data System (ADS)

    Belrose, John S.; Royer, G. M.; Petrie, L. E.

    1989-09-01

    The considerable combined experience with numerical and experimental modeling, with fabricating, with measuring performance of and with using practical HF antennas for the low HF band (2 to 8 MHz) is examined. The antenna poses a particularly difficult problem for this frequency band, particularly if a broad-band antenna is wanted for frequency agile systems, because of the four-to-one change in wavelength over the band. A further complication is that as the frequency is reduced so is the electrical height of the antenna above the ground, and since the ground is an imperfect conductor, the finite conductivity of the ground introduces loss of gain, and detuning. There is great concern with antennas at low (electrical) heights, even with antennas very near to or actually lying on the ground. Antennas lying on or near the ground are of particular interest for military tactical communicators, since low profile antenna systems that require no support mast or masts are operationally and logistically an advantage for use in a tactical environment. HF radio operators in the Canadian north have frequently reported success with using HF dipoles lying on the ground. The reason that antennas perform at all under the circumstances is because of the very low ground conductivities found in the Canadian north. It is shown what gain to expect under such circumstances. The comparison between computer simulation with measurement is emphasized, and with the application of computers for both numerical modeling, measurement, and data analysis and presentation.

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

    PubMed

    Mondal, Sukanta; Chattaraj, Pratim Kumar

    2014-09-01

    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. PMID:25047071

  5. 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.

  6. 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.

  7. Treatment disparities in acute coronary syndromes, heart failure, and kidney disease.

    PubMed

    McCullough, Peter A; Maynard, Robert C

    2011-01-01

    It has been consistently observed that patients with renal dysfunction have more premature, severe, complicated, and fatal cardiovascular disease than age- and sex-matched individuals with normal renal function. There have been 4 major explanations for this finding: (1) positive confounding by third variables associated with chronic kidney disease (CKD), including diabetes mellitus and hypertension; (2) therapeutic nihilism or lesser use of beneficial therapies in CKD; (3) greater toxicities of therapies, such as bleeding from anticoagulants or contrast-induced kidney injury; (4) biological factors which result directly from CKD that work to promote and accelerate cardiovascular disease. In this paper, we focus on the issue of treatment disparities or therapeutic nihilism and its contribution to poor outcomes in the setting of acute coronary syndromes and acutely decompensated heart failure. This issue is important because if we can overcome barriers to the utilization of beneficial treatments, then clinical outcomes should improve over time.

  8. Treatment disparities in acute coronary syndromes, heart failure, and kidney disease.

    PubMed

    McCullough, Peter A; Maynard, Robert C

    2011-01-01

    It has been consistently observed that patients with renal dysfunction have more premature, severe, complicated, and fatal cardiovascular disease than age- and sex-matched individuals with normal renal function. There have been 4 major explanations for this finding: (1) positive confounding by third variables associated with chronic kidney disease (CKD), including diabetes mellitus and hypertension; (2) therapeutic nihilism or lesser use of beneficial therapies in CKD; (3) greater toxicities of therapies, such as bleeding from anticoagulants or contrast-induced kidney injury; (4) biological factors which result directly from CKD that work to promote and accelerate cardiovascular disease. In this paper, we focus on the issue of treatment disparities or therapeutic nihilism and its contribution to poor outcomes in the setting of acute coronary syndromes and acutely decompensated heart failure. This issue is important because if we can overcome barriers to the utilization of beneficial treatments, then clinical outcomes should improve over time. PMID:21625092

  9. 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.

  10. The stability of the bifluoride ion (HF - 2) in the gas phase

    NASA Astrophysics Data System (ADS)

    Heni, Martin; Illenberger, Eugen

    1985-12-01

    The bifluoride ion (HF-2) has been generated by dissociative electron attachment to trans-1,2-difluorethylene and cis-1,2-difluoroethylene. Evaluation of the energetics for these reactions leads to ΔH0f (HF-2) ≤-6.9 eV and E. A. (HF2)≥4.8 eV.

  11. 75 FR 10186 - Beauveria bassiana HF23; Amendment of Exemption from the Requirement of a Tolerance

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-05

    ... granting a tolerance exemption for Beauveria bassiana HF23 (Unit III.A. and B., 72 FR 1177, January 10... AGENCY 40 CFR Part 180 Beauveria bassiana HF23; Amendment of Exemption from the Requirement of a... the need to establish a maximum permissible level for residues of Beauveria bassiana HF23. DATES:...

  12. 40 CFR 180.1273 - Beauveria bassiana HF23; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 24 2011-07-01 2011-07-01 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...

  13. 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...

  14. 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.

  15. 176Lu-176Hf geochronology of garnet I: experimental determination of the diffusion kinetics of Lu3+ and Hf4+ in garnet, closure temperatures and geochronological implications

    NASA Astrophysics Data System (ADS)

    Bloch, Elias; Ganguly, Jibamitra; Hervig, Richard; Cheng, Weiji

    2015-02-01

    The 176Lu-176Hf and 147Sm-143Nd decay systems are routinely used to determine garnet (Grt)-whole-rock (WR) ages; however, the 176Lu-176Hf age of garnet is typically older than the 147Sm-143Nd age determined from the same aliquots. Here we present experimental data for Lu3+ and Hf4+ diffusion in garnet as functions of temperature, pressure and oxygen fugacity and show that the diffusivity of Hf4+ in almandine/spessartine garnet is significantly slower than that of Lu3+. The diffusive closure temperature ( T C) of Hf4+ is significantly higher than that of Nd3+, and although this property is partly responsible for the observed 176Lu-176Hf and 147Sm-143Nd Grt-WR age discrepancies, the difference between the T C-s of Lu3+ and Hf4+ could lead to apparent Grt-WR 176Lu-176Hf ages that are skewed from the age of Hf4+ closure in garnet. In addition, the slow diffusivity of Hf4+ indicates that the bulk of metamorphic garnets retain a substantial fraction of prograde radiogenic 176Hf throughout peak metamorphic conditions, a phenomenon that further complicates the interpretation of 176Lu-176Hf garnet ages and invalidates the use of analytical T C expressions. We argue that the diffusion of trivalent rare earth elements in garnet becomes much faster when their concentration level falls below a few hundred ppm, as in the experiments of Tirone et al. (Geochim Cosmochim Acta 69: 2385-2398, 2005), and further argue that this low-concentration mechanism is appropriate for modeling the susceptibility of 147Sm-143Nd garnet ages to diffusive resetting.

  16. 3-Methylcrotonyl-CoA carboxylase deficiency: metabolic decompensation in a noncompliant child detected through newborn screening.

    PubMed

    Ficicioglu, Can; Payan, Irma

    2006-12-01

    We report a 19-month-old girl with a 3-methylcrotonyl-coenzyme A carboxylase deficiency that was detected through newborn screening. She was treated for the first 12 months but was lost to follow-up after the initial year. Her parents did not comply with the recommendations for management during periods of illness or for regular medical evaluations. During an acute illness, she presented with severe acidosis, hypoglycemia, and a low plasma carnitine level at 19 months of age. This report highlights the importance of more extensive follow-up plans to improve parental compliance.

  17. 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.

  18. Effect of substitutional carbon-doping in BNNTs on HF adsorption: DFT study

    NASA Astrophysics Data System (ADS)

    Kaur, Jasleen; Singhal, Sonal; Goel, Neetu

    2014-11-01

    We employed density functional calculations to investigate the adsorption behavior of HF gas on the side walls of pure and carbon-doped boron nitride nanotubes (BNNTs). The HF adsorption over the pure BNNT opens a door for its functionalization without causing significant changes in its electronic properties. The substitutional doping of carbon atom on the BNNT considerably enhances its affinity towards HF where the effect of the dopant concentration plays a vital role. The change in electronic properties of the doped BNNT on HF adsorption is significant enough to consider it a potential sensor for HF detection.

  19. Charge storage characteristics and tunneling mechanism of amorphous Ge-doped HfOx films

    NASA Astrophysics Data System (ADS)

    Qiu, X. Y.; Zhang, S. Y.; Zhang, T.; Wang, R. X.; Li, L. T.; Zhang, Y.; Dai, J. Y.

    2016-09-01

    Amorphous Ge-doped HfOx films have been deposited on p-Si(100) substrates by means of RF magnetron sputtering. Microstructural investigations reveal the partial oxidation of doped Ge atoms in the amorphous HfOx matrix and the existence of HfSiOx interfacial layer. Capacitance-voltage hysteresis of the Ag-/Ge-doped HfOx/Si/Ag memory capacitor exhibits a memory window of 3.15 V which can maintain for >5 × 104 cycles. Current-voltage characteristics reveal that Poole-Frenkel tunneling is responsible for electron transport in the Ge-doped HfOx film.

  20. Acute-on-Chronic Liver Failure.

    PubMed

    Asrani, Sumeet K; Simonetto, Douglas A; Kamath, Patrick S

    2015-11-01

    Over the past 2 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 thus is 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 an increased risk for mortality are key to the diagnosis of ACLF. The prevalence of ACLF ranges from 24% to 40% in hospitalized patients. The pathophysiological basis of ACLF can be explained using the following 4-part model: predisposing event, injury caused by a precipitating event, response to injury, and organ failure. Although several mathematic scores have been proposed for identifying outcomes with ACLF, it is as yet unclear whether these organ failure scores are truly prognostic or only reflective of the dying process. Treatment paradigms continue to evolve but consist of early recognition, supportive intensive care, and consideration of liver transplantation before onset of irreversible multiple organ failure. PMID:26188138

  1. 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.

  2. Combination of lung ultrasound (a comet-tail sign) and N-terminal pro-brain natriuretic peptide in differentiating acute heart failure from chronic obstructive pulmonary disease and asthma as cause of acute dyspnea in prehospital emergency setting

    PubMed Central

    2011-01-01

    Introduction We studied the diagnostic accuracy of bedside lung ultrasound (the presence of a comet-tail sign), N-terminal pro-brain natriuretic peptide (NT-proBNP) and clinical assessment (according to the modified Boston criteria) in differentiating heart failure (HF)-related acute dyspnea from pulmonary (chronic obstructive pulmonary disease (COPD)/asthma)-related acute dyspnea in the prehospital setting. Methods Our prospective study was performed at the Center for Emergency Medicine, Maribor, Slovenia, between July 2007 and April 2010. Two groups of patients were compared: a HF-related acute dyspnea group (n = 129) and a pulmonary (asthma/COPD)-related acute dyspnea group (n = 89). All patients underwent lung ultrasound examinations, along with basic laboratory testing, rapid NT-proBNP testing and chest X-rays. Results The ultrasound comet-tail sign has 100% sensitivity, 95% specificity, 100% negative predictive value (NPV) and 96% positive predictive value (PPV) for the diagnosis of HF. NT-proBNP (cutoff point 1,000 pg/mL) has 92% sensitivity, 89% specificity, 86% NPV and 90% PPV. The Boston modified criteria have 85% sensitivity, 86% specificity, 80% NPV and 90% PPV. In comparing the three methods, we found significant differences between ultrasound sign and (1) NT-proBNP (P < 0.05) and (2) Boston modified criteria (P < 0.05). The combination of ultrasound sign and NT-proBNP has 100% sensitivity, 100% specificity, 100% NPV and 100% PPV. With the use of ultrasound, we can exclude HF in patients with pulmonary-related dyspnea who have positive NT-proBNP (> 1,000 pg/mL) and a history of HF. Conclusions An ultrasound comet-tail sign alone or in combination with NT-proBNP has high diagnostic accuracy in differentiating acute HF-related from COPD/asthma-related causes of acute dyspnea in the prehospital emergency setting. Trial registration ClinicalTrials.gov NCT01235182. PMID:21492424

  3. Electrochemical oxide nanotube formation on the Ti-35Ta-xHf alloys for dental materials.

    PubMed

    Moon, Byung-Hak; Jeong, Yong-Hoon; Choe, Han-Cheol

    2011-08-01

    In this study, we investigated the electrochemical oxide nanotube formation on the Ti-35Ta-xHf alloys for dental materials. The Ti-35Ta-xHf alloys contained from 3 wt.% to 15 wt.% Hf were manufactured by arc melting furnace. The nanotube oxide layers were formed on Ti-35Ta-xHf alloy by anodic oxidation method in 1 M H3PO4 electrolytes containing 0.5 wt.% NaF and 0.8 wt.% NaF at room temperature. The surface characteristics of Ti-35Ta-xHf alloy and nanotube morphology were determined by FE-SEM, STEM, and XRD. The nano-porous surface of Ti-35Ta-xHf alloys showed in 0.5 wt% NaF solution and nanotubular surface showed in 0.8 wt% NaF solution, respectively. The highly ordered nanotube layer without regular knots was formed on the Ti-35Ta-15Hf alloy in the 0.5 wt% NaF solution compared to on Ti-35Ta-3Hf and Ti-35Ta-7Hf alloys in 0.8 wt% NaF solution. Also, the nanotube length of Ti-35Ta-xHf alloys increased as Hf content increased.

  4. Intrinsic metastability of orthorhombic HfTiO{sub 4} in thin film hafnia-titania

    SciTech Connect

    Cisneros-Morales, Massiel Cristina; Aita, Carolyn Rubin

    2011-01-31

    Orthorhombic (o) HfTiO{sub 4} is crystallized when sputter deposited hafnia-titania nanolaminates with ultrathin layers and bilayer (HfO{sub 2}){sub 0.5}(TiO{sub 2}){sub 0.5} composition are annealed between 573 and 1173 K. However, o-HfTiO{sub 4} demixes after annealing at 1273 K, a result not predicted from bulk thermodynamics. X-ray diffraction and Raman microscopy are used here to study structural changes as o-HfTiO{sub 4} demixes upon long-term annealing at 1273 K into Ti-doped monoclinic HfO{sub 2} and Hf-doped rutile TiO{sub 2}. We conclude that o-HfTiO{sub 4} crystallized at low temperature is intrinsically metastable. A space group symmetry analysis shows that demixing can be accomplished by a continuous phase transition chain.

  5. 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.

  6. Field emission from single-crystalline HfC nanowires

    SciTech Connect

    Yuan, Jinshi; Tang, Jie; Zhang Han; Shinya, Norio; Nakajima, Kiyomi; Qin, Lu-Chang

    2012-03-12

    Single HfC nanowire field emitter/electrode structures have been fabricated using nano-assembling and electron beam induced deposition. Field ion microscopy has been applied to study the atomic arrangement of facets formed on a field evaporation-modified HfC nanowire tip. Field evaporation and crystal form studies suggest that the {l_brace}111{r_brace} and {l_brace}110{r_brace} crystal planes have lower work functions, while the {l_brace}100{r_brace}, {l_brace}210{r_brace}, and {l_brace}311{r_brace} planes have higher work functions. Field emission measurement permits us to obtain that the work function of the {l_brace}111{r_brace} crystal plane is about 3.4 eV.

  7. 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.

  8. CMS HF calorimeter PMTs and Xi(c)+ lifetime measurement

    SciTech Connect

    Akgun, Ugur; /Iowa U.

    2003-12-01

    This thesis consists of two parts: In the first part we describe the Photomultiplier Tube (PMT) selection and testing processes for the Hadronic Forward (HF) calorimeter of the CMS, a Large Hadron Collier (LHC) experiment at CERN. We report the evaluation process of the candidate PMTs from three different manufacturers, the complete tests performed on the 2300 Hamamatsu PMTs which will be used in the HF calorimeter, and the details of the PMT Test Station that is in University of Iowa CMS Laboratories. In the second part we report the {Xi}{sub c}{sup +} lifetime measurement from SELEX, the charm hadro-production experiment at Fermilab. Based upon 301 {+-} 31 events from three di.erent decay channels, by using the binned maximum likelihood technique, we observe the lifetime of {Xi}{sub c}{sup +} as 427 {+-} 31 {+-} 13 fs.

  9. Dislocation structures in Ni{sub 3}(Al,Hf)

    SciTech Connect

    Kruml, T.; Viguier, B.; Bonneville, J.; Martin, J.L.; Spaetig, P.

    1997-12-31

    Single crystalline specimens of Ni{sub 74.8}Al{sub 21.9}Hf{sub 3.3} were subjected to compression tests at different temperatures. Thin foils for transmission electron microscopy observations were prepared from several specimens deformed within and above the yield stress anomaly domain. The dislocation microstructure was studied. The weak beam imaging and image simulation techniques followed by anisotropic elasticity calculations were used for the determination of antiphase boundary energies in both cube and octahedral planes, resulting in values of 237 mJm{sup {minus}2} and 252 mJm{sup {minus}2} respectively. The comparison of the present results with data taken from literature shows the influence of Hf on mechanical properties, dislocation microstructures and APB energies.

  10. Crossbar Nanoscale HfO2-Based Electronic Synapses

    NASA Astrophysics Data System (ADS)

    Matveyev, Yury; Kirtaev, Roman; Fetisova, Alena; Zakharchenko, Sergey; Negrov, Dmitry; Zenkevich, Andrey

    2016-03-01

    Crossbar resistive switching devices down to 40 × 40 nm2 in size comprising 3-nm-thick HfO2 layers are forming-free and exhibit up to 105 switching cycles. Four-nanometer-thick devices display the ability of gradual switching in both directions, thus emulating long-term potentiation/depression properties akin to biological synapses. Both forming-free and gradual switching properties are modeled in terms of oxygen vacancy generation in an ultrathin HfO2 layer. By applying the voltage pulses to the opposite electrodes of nanodevices with the shape emulating spikes in biological neurons, spike-timing-dependent plasticity functionality is demonstrated. Thus, the fabricated memristors in crossbar geometry are promising candidates for hardware implementation of hybrid CMOS-neuron/memristor-synapse neural networks.

  11. Acute gastroenteritis.

    PubMed

    Graves, Nancy S

    2013-09-01

    Acute gastroenteritis is a common infectious disease syndrome, causing a combination of nausea, vomiting, diarrhea, and abdominal pain. There are more than 350 million cases of acute gastroenteritis in the United States annually and 48 million of these cases are caused by foodborne bacteria. Traveler's diarrhea affects more than half of people traveling from developed countries to developing countries. In adult and pediatric patients, the prevalence of Clostridium difficile is increasing. Contact precautions, public health education, and prudent use of antibiotics are necessary goals in decreasing the prevalence of Clostridium difficle. Preventing dehydration or providing appropriate rehydration is the primary supportive treatment of acute gastroenteritis.

  12. 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

  13. Mapping high-latitude plasma convection with coherent HF radars

    NASA Technical Reports Server (NTRS)

    Ruohoniemi, J. M.; Greenwald, R. A.; Baker, K. B.; Villain, J.-P.; Hanuise, C.

    1989-01-01

    Several methods developed for mapping high-latitude plasma convection with a high-latitude HF radar are described, which utilize coherent backscatter from electron density irregularities at F-region altitudes to observe convective plasma motion. Several examples of two-dimensional convection-velocity maps are presented, showing instances of L-shell-aligned flow in the dusk sector, the reversal of convection near magnetic midnight, and counterstreaming in the dayside cleft.

  14. Gas consumption characteristics of a recirculating HF-laser.

    PubMed

    Willis, C; Dosi, M; James, D J

    1979-05-01

    The gas consumption characteristics of a recirculating HF TE-laser have been defined. The stoichiometry varies from close to H(2):SF(6):1:1 at low H(2) concentration to 3:1 above 30% H(2). The output energy shows a broad maximum in its dependence on pressure and H(2) concentration and, as a result fairly stable output can be maintained with recirculation using only a simple make-up control system.

  15. 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).

  16. Ionosphere Transient Response To Solar Flares: Hf Radio Monitoring Observations

    NASA Astrophysics Data System (ADS)

    Lebreton, J.-P.; Telljohann, U.; Witasse, O.; Sanderson, T. R.

    We use a simple and low cost method to monitor the ionospheric reflection of commer- cial HF radio transmissions. It only requires a standard HF radio receiver with Single Side Band capability, a computer with a sound card, and appropriate audio signal spectral analysis software. We tune the radio receiver such that the carrier frequency of the transmission appears as a ~ 1kHz tone at the output of the radio receiver. The output signal of the radio receiver is processed with appropriate software that allows real time recording of high frequency resolution dynamic spectrograms of the audio spectrum in the 0-5 kHz range. Voice modulation is also present in the audio spectrum and appears as both upper and lower side bands but it is not considered in this study. HF radio signals reach the receiving station after being reflected by ionospheric layers. Any change in the ionospheric layers that affects HF wave reflection is detectable. In this paper, we particularly discuss our observations related to the transient response of the ionosphere to solar flare ionizing radiation. Enhanced ionization due to EUV and soft X-rays may produce a transient perturbation of the ionosphere which lasts typically one to few minutes. The signature of the transient response depends upon local time, solar flare intensity and the rise time of the solar flare ionizing radiation. We discuss both a few typical examples and a preliminary analysis of our 1-year sta- tistical analysis of observed events at 17.640 MHz. The method is easily accessible to amateur scientists. Possible use of the method for spaceweather-related research and outreach and educational activities is discussed.

  17. Solidification Effects in MAR-M246(Hf) Alloy

    NASA Technical Reports Server (NTRS)

    Johnston, M. H.; Parr, R. A.

    1987-01-01

    Fatigue properties degraded with crystallographic orientations greater than 10 degrees from {001} axis. Influence of solidification and heat-treatment parameters on structure and fatigue properties of nickel-based superalloy MAR-M246(Hf) described in 24-page report. Superalloys have high strength and corrosion resistance at temperatures up to 1,400 degrees C; their uses range from petrochemical equipment to marine, industrial, aircraft, and vehicular gas turbines.

  18. 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

  19. Electrochemical characterization of cast Ti-Hf binary alloys.

    PubMed

    Cai, Z; Koike, M; Sato, H; Brezner, M; Guo, Q; Komatsu, M; Okuno, O; Okabe, T

    2005-05-01

    This study characterized the electrochemical behavior of Ti-Hf binary alloys in a simulated oral environment. Ti-Hf alloys (10, 20, 25, 30, 35 and 40 mass% Hf) were prepared by arc-melting titanium sponge and hafnium sponge. Specimens of each alloy (n = 4) were prepared using a dental titanium casting system with a MgO-based investment. Specimens were inspected with X-ray radiography to ensure minimal internal porosity. Castings (n = 4) made from pure titanium and commercially pure titanium were used as controls. The ground flat surface (10 mm x 10 mm) on each specimen where approximately 30 microm was removed was used for the characterization. Sixteen-hour open-circuit potential (OCP) measurement, linear polarization and potentiodynamic cathodic polarization were performed sequentially in aerated (air + 10% CO2) MTZ synthetic saliva at 37 degrees C. Potentiodynamic anodic polarization was conducted in the same medium but deaerated (N2 + 10% CO2) 2 h before and during testing. Polarization resistance (R(P)) and Tafel slopes were determined, as were corrosion current density (I(CORR)) and passive current density (I(PASS)). Results were subjected to nonparametric statistical analysis (alpha = 0.05). The OCP stabilized (mean values -229 mV to -470 mV vs. SCE) for all specimens after the 16-h immersion. Similar passivation was observed for all the metals on their anodic polarization diagrams. The Kruskal-Wallis test showed significant differences in OCP among the test groups (p = 0.006). No significant differences were found in R(P), I(CORR) or I(PASS) among all the metals (p>0.3). Results indicate that the electrochemical behavior of the Ti-Hf alloys examined resembles that of pure titanium. PMID:16701813

  20. Growth, microstructure and electrical properties of sputter-deposited hafnium oxide (HfO2) thin films grown using HfO2 ceramic target

    SciTech Connect

    Aguirre, B.; Vemuri, R. S.; Zubia, David; Engelhard, Mark H.; Shutthanandan, V.; Kamala Bharathi, K.; Ramana, Chintalapalle V.

    2011-01-01

    Hafnium oxide (HfO₂) thin films have been made by radio-frequency (rf) magnetron-sputtering onto Si(100) substrates under varying growth temperature (Ts). HfO₂ ceramic target has been employed for sputtering while varying the Ts from room temperature to 500⁰C during deposition. The effect of Ts on the growth and microstructure of deposited HfO₂ films has been studied using grazing incidence x-ray diffraction (GIXRD), X-ray photoelectron spectroscopy (XPS), and high-resolution scanning electron microscopy (HR-SEM) coupled with energy dispersive x-ray spectrometry (EDS). The results indicate that the effect of Ts is significant on the growth, surface and interface structure, morphology and chemical composition of the HfO₂ films. Structural characterization indicates that the HfO₂ films grown at Ts<200 ⁰C are amorphous while films grown at Ts>200 ⁰C are nanocrystalline. An amorphous-to-crystalline transition occurs at Ts=200 ⁰C. Nanocrystalline HfO₂ films crystallized in a monoclinic structure with a (-111) orientation. XPS measurements indicated the high surface-chemical quality and stoichiometric nature of the grown HfO₂ films. An interface layer (IL) formation occurs due to reaction at the HfO₂-Si interface for HfO₂ films deposited at Ts>200 ⁰C. The thickness of IL increases with increasing Ts. XPS and EDS at the HfO₂-Si cross-section indicate the IL is a (Hf, Si)-O compound. The electrical characterization using capacitance-voltage measurements indicate that the dielectric constant decreases from 25 to 16 with increasing Ts.

  1. Stretching exercises enhance vascular endothelial function and improve peripheral circulation in patients with acute myocardial infarction.

    PubMed

    Hotta, Kazuki; Kamiya, Kentaro; Shimizu, Ryosuke; Yokoyama, Misako; Nakamura-Ogura, Misao; Tabata, Minoru; Kamekawa, Daisuke; Akiyama, Ayako; Kato, Michitaka; Noda, Chiharu; Matsunaga, Atsuhiko; Masuda, Takashi

    2013-01-01

    The purpose of this study was to clarify the acute effects of a single session of stretching exercises on vascular endothelial function and peripheral circulation in patients with acute myocardial infarction. This study evaluated 32 patients (mean age, 66 ± 9 years) who received phase I cardiac rehabilitation after acute myocardial infarction. Five types of stretching exercises were performed on the floor: wrist dorsiflexion, close-legged trunk flexion, open-legged trunk flexion, open-legged lateral trunk bending, and cross-legged trunk flexion. Each exercise entailed a 30-second stretching followed by a 30-second relaxation, and was repeated twice. Low- and high-frequency components (LF and HF) of heart rate variability (LF, 0.04-0.15 Hz; HF, 0.15-0.40 Hz) were analyzed, and HF and LF/HF were used as indices of parasympathetic and sympathetic nervous activities, respectively. Reactive hyperemia peripheral arterial tonometry (RH-PAT) index was measured and used as a parameter for vascular endothelial function. Transcutaneous oxygen pressure (tcPO2) on the right foot and chest was also measured, and the Foot-tcPO2/Chest-tcPO2 ratio was used as a parameter for peripheral circulation. The HF, RH-PAT index, and Foot-tcPO2/Chest-tcPO2 ratio were significantly higher after the exercises than before (P < 0.05, P < 0.01, and P < 0.05, respectively). There was no significant difference in the LF/HF ratio measured before and after stretching exercises. These findings demonstrate that stretching exercises improve vascular endothelial function and peripheral circulation in patients with acute myocardial infarction.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. Superconductivity in the noncentrosymmetric compound Re6Hf

    NASA Astrophysics Data System (ADS)

    Chen, Bin; Guo, Yang; Wang, Hangdong; Su, Qiping; Mao, Qianhui; Du, Jianhua; Zhou, Yuxing; Yang, Jinhu; Fang, Minghu

    2016-07-01

    Re6Hf , which crystallizes in α -Mn structure(space group I 4 ¯3 m ) without a spatial inversion center, is a superconductor with a superconducting transition temperature Tc≈6.2 K . The measurements of magnetic susceptibility (χ ), resistivity (ρ ), and specific heat capacity (C ) were carried out. Bulk superconductivity is revealed by the jump at Tc of the specific heat with Δ C /γnTc≈1.63 , suggesting moderate electron-electron coupling strength in this system. The upper critical field μ0Hc2 W H H(0 ) was estimated to be of 89 kOe, and μ0Hc2 G L(0 ) =107 kOe, which is close to the Pauli limiting field. The Ginzburg Landau parameter κG L=50.2 , indicates that Re6Hf is a type-II superconductor. The temperature dependence of the electronic specific heat Ce l(T ) in the superconducting state can be explained by BCS theory. Furthermore, the magnetic-field dependence of γ (H ) is found to be linear with respect to H . These results imply a dominant s -wave superconductivity in Re6Hf .

  7. Detection of HCl and HF by TTFMS and WMS.

    PubMed

    De Luca, Anna Chiara; Pesce, Giuseppe; Rusciano, Giulia; Sasso, Antonio

    2006-04-01

    In this work we discuss on a compact spectrometer based on DFB diode lasers for detection of chloridric and fluoridric acids. HCl and HF concentrations are determined through optical absorption of the P(4) line (lambda=1.7 microm) and the R(3) line (lambda=1.3 microm), respectively. Both lines belong to first overtone vibrational bands and their line strengths are 7.8 x 10(-21)cm/molecule for HCl and 2.8 x 10(-20)cm/molecule for HF. We chose these lines for their relative high intensities and because they are quite far from water vapour lines which represent the main interfering gas for trace-gases analysis. To detect these species we used two different high frequency modulation techniques: two-tone frequency modulation spectroscopy (f(1)=800 MHz and f(2)=804 MHz) was used for HCl while for HF we followed a simpler approach based on wavelength modulation spectroscopy (f=600 kHz). We demonstrate that the two techniques provide comparable detection limit of about 80 ppbV at atmospheric pressure. Positive testing of our spectrometer makes it suitable for in situ measurements of exhaust gases coming from waste incinerators.

  8. 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. PMID:27277148

  9. Acute Bronchitis

    MedlinePlus

    ... bronchitis? Acute bronchitis is almost always caused by viruses that attack the lining of the bronchial tree ... infection. As your body fights back against these viruses, more swelling occurs and more mucus is produced. ...

  10. Acute Pericarditis

    MedlinePlus

    ... large pericardial effusions). Acute pericarditis usually responds to colchicine or NSAIDs (such as aspirin and ibuprofen ) taken ... reduce pain but relieves it by reducing inflammation. Colchicine also decreases the chance of pericarditis returning later. ...

  11. 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

  12. Prognostic biomarkers in acute coronary syndrome.

    PubMed

    Salvagno, Gian Luca; Pavan, Chiara

    2016-07-01

    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

  13. 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.

  14. 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.

  15. H-shuttling within a Hf-defect complex in Si/SiO2/HfO2 structures

    NASA Astrophysics Data System (ADS)

    Marinopoulos, A. G.; Batyrev, I.; Zhou, X.; Schrimpf, R.; Fleetwood, D.; Pantelides, S. T.

    2008-03-01

    It was recently shown that, following irradiation of Si-SiO2/HfO2 structures by X-rays or constant-voltage stress, both oxide- and interface-trap densities exhibit oscillations with switch-bias annealing that are much larger than those previously observed in Si/SiO2 devices. Here we describe a particular defect complex that can account for the observations. The complex comprises a suboxide Hf-Si bond and an interfacial dangling bond (Pb center). With the aid of first-principles calculations we show that this defect possesses a symmetric double-well minimum and can provide trapping sites for H atoms near the interface. In the first site, the H atom passivates the dangling bond; in the second site the H atom resides near the center of the Hf-Si bond. A moderate intervening barrier (1.2 eV) suggests a relatively easy hopping of H atoms between these two energy minima, aided by the applied field and temperature. This shuttling mechanism can explain the observed oscillations in the interface trap densities during switched-bias conditions. This work was supported in part by the AFOSR and the DOE.

  16. 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).

  17. Vertically oriented few-layered HfS2 nanosheets: growth mechanism and optical properties

    NASA Astrophysics Data System (ADS)

    Zheng, Binjie; Chen, Yuanfu; Wang, Zegao; Qi, Fei; Huang, Zhishuo; Hao, Xin; Li, Pingjian; Zhang, Wanli; Li, Yanrong

    2016-09-01

    For the first time, large-area, vertically oriented few-layered hafnium disulfide (V-{{{HfS}}}2) nanosheets have been grown by chemical vapor deposition. The individual {{{HfS}}}2 nanosheets are well [001] oriented, with highly crystalline quality. Far different from conventional van der Waals epitaxial growth mechanism for two-dimensional transition metal dichalcogenides, a novel dangling-bond-assisted self-seeding growth mechanism is proposed to describe the growth of V-{{{HfS}}}2 nanosheets: difficult migration of {{{HfS}}}2 adatoms on substrate surface results in {{{HfS}}}2 seeds growing perpendicularly to the substrate; V-{{{HfS}}}2 nanosheets inherit the growth direction of {{{HfS}}}2 seeds; V-{{{HfS}}}2 nanosheets further expand in the in-plane direction with time evolution. Moreover, the V-{{{HfS}}}2 nanosheets show strong and broadened photons absorption from near infrared to ultraviolet; the V-{{{HfS}}}2-based photodetector exhibits an ultrafast photoresponse time of 24 ms, and a high photosensitivity ca. 103 for 405 nm laser.

  18. Hafnium sulfate prenucleation clusters and the Hf(18) polyoxometalate red herring.

    PubMed

    Ruther, Rose E; Baker, Brenna M; Son, Jung-Ho; Casey, William H; Nyman, May

    2014-04-21

    In prior studies, aqueous Hf sulfate-peroxide solutions were spin-coated, dehydrated, patterned by electron-beam lithography, ion-exchanged (OH(-) for SO4(2-)), and finally converted to HfO2 hard masks via annealing. The atomic-level details of the underlying aqueous chemistries of these processes are complex and yet to be understood. Yet a thorough understanding of this specific chemical system will inspire development of design rules for other aqueous-precursor-to-solid-state metal oxide systems. Often-observed crystallization of the Hf18 polyoxometalate from aqueous Hf sulfate-peroxide precursor solutions has led us to believe that Hf18 may represent an important intermediate step in this process. However, via detailed solution studies described here (small-angle X-ray scattering, electrospray ionization mass spectrometry, and Raman spectroscopy), we ascertained that Hf18 is in fact not a prenucleation cluster of Hf sulfate coatings. Rather, the Hf tetramers, pentamers, and hexamers that are the core building blocks of Hf18 are robustly persistent over variable compositions and aging time of precursor solutions, and therefore they are likely the rudimentary building blocks of the deposited thin-film materials. These Hf clusters are capped and linked by sulfate and peroxide anions in solution, which probably prevents crystallization of Hf18 during the rapid dehydration process of spin-coating. In fact, crystallization of Hf18 from the amorphous gel coating would be detrimental to formation of a high-density conformal coating that we obtain from precursor solutions. Therefore, this study revealed that the well-known Hf18 polyoxometalate is not likely to be an important intermediate in the thin-film process. However, its subunits are, confirming the universal importance of deriving information from the solid state, albeit judiciously and critically, to understand the solution state.

  19. Reliability assessment of ultra-thin HfO2 films deposited on silicon wafer

    NASA Astrophysics Data System (ADS)

    Fu, Wei-En; Chang, Chia-Wei; Chang, Yong-Qing; Yao, Chih-Kai; Liao, Jiunn-Der

    2012-09-01

    Ultra-thin hafnium dioxide (HfO2) is used to replace silicon dioxide to meet the required transistor feature size in advanced semiconductor industry. The process integration compatibility and long-term reliability for the transistors depend on the mechanical performance of ultra-thin HfO2 films. The criteria of reliability including wear resistance, thermal fatigue, and stress-driven failure rely on film adhesion significantly. The adhesion and variations in mechanical properties induced by thermal annealing of the ultra-thin HfO2 films deposited on silicon wafers (HfO2/SiO2/Si) are not fully understood. In this work, the mechanical properties of an atomic layer deposited HfO2 (nominal thickness ≈10 nm) on a silicon wafer were characterized by the diamond-coated tip of an atomic force microscope and compared with those of annealed samples. The results indicate that the annealing process leads to the formation of crystallized HfO2 phases for the atomic layer deposited HfO2. The HfSixOy complex formed at the interface between HfO2 and SiO2/Si, where the thermal diffusion of Hf, Si, and O atoms occurred. The annealing process increases the surface hardness of crystallized HfO2 film and therefore the resistance to nano-scratches. In addition, the annealing process significantly decreases the harmonic contact stiffness (or thereafter eliminate the stress at the interface) and increases the nano-hardness, as measured by vertically sensitive nano-indentation. Quality assessments on as-deposited and annealed HfO2 films can be thereafter used to estimate the mechanical properties and adhesion of ultra-thin HfO2 films on SiO2/Si substrates.

  20. 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.

  1. Strong photoluminescence of the porous silicon with HfO{sub 2}-filled microcavities

    SciTech Connect

    Jiang, Ran; Wu, Zhengran; Du, Xianghao; Han, Zuyin; Sun, Weideng

    2015-06-22

    Greatly enhanced blue emission was observed at room temperature in the single-crystal silicon with HfO{sub 2} filled into its microcavities. The broad blue band light was emitted from both the HfO{sub 2} dielectric and the porous Si. The ferroelectricity of HfO{sub 2} enhances the blue emission from Si by its filling into the microcaivities. At the same time, HfO{sub 2} 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 HfO{sub 2} dielectric is remarkable as both HfO{sub 2} and Si are highly compatible with Si-based electronic industry.

  2. 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.

  3. 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.

  4. A coupled ionosphere-raytrace model for high-power HF heating

    NASA Astrophysics Data System (ADS)

    Zawdie, K. A.; Huba, J. D.; Drob, D. P.; Bernhardt, P. A.

    2015-11-01

    The first 3-D model of artificial HF ionospheric heating to self-consistently calculate the modification in heating location due to evolving ionospheric gradients has been developed. The model combines the ionosphere model SAMI3/ESF and the HF propagation code MoJo-15. At each time step, the simulated path of the HF wave through the ionosphere is used to determine the HF heating location. These calculations have been used to explain the physical mechanism responsible for the snapback effect observed in an Arecibo HF heating experiment described by Bernhardt et al. (1988). The heater wave is refracted by the density cavity, which causes the heating location to drift in longitude. Eventually, the density cavity convects into the path of the refracted ray, such that only a small portion of the ray is above the threshold for HF heating and the heating location snaps back even though the ray itself is still refracted in longitude.

  5. Simultaneous measurements of HF-enhanced plasma waves and artificial field-aligned irregularities at Arecibo

    NASA Astrophysics Data System (ADS)

    Noble, S. T.; Djuth, F. T.

    1990-09-01

    A study aimed at examining the coupling between HF-induced Langmuir waves and artificially produced field-aligned irregularities is presented. The HF-enhanced plasma lines (HFPLs) were monitored with the Arecibo 430-MHz radar while simultaneous measurements of artificial geomagnetic field-aligned irregularities (AFAIs) were made with a mobile 49.92-MHz radar. The HF power was systematically increased and then decreased during the experimental period when a single data set was obtained under nearly ideal observing conditions. As the HF power is increased, the HFPL backscatter power starts to saturate at about 70 MW effective radiated power (ERP). However, the backscatter from AFAIs is linearly dependent on HF power, even at the greatest (120 MW ERP) HF power levels available at Arecibo.

  6. Microstructure dependent filament forming kinetics in HfO2 programmable metallization cells.

    PubMed

    Clarke, Heidi; Brown, Timothy; Hu, Jianjun; Ganguli, Raj; Reed, Amber; Voevodin, Andrey; Shamberger, Patrick J

    2016-10-21

    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.

  7. 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.

  8. 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

  9. 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. PMID:25870298

  10. 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.

  11. Nonalcoholic Fatty Liver Disease Is Associated With Higher 1-year All-Cause Rehospitalization Rates in Patients Admitted for Acute Heart Failure

    PubMed Central

    Valbusa, Filippo; Bonapace, Stefano; Grillo, Cristina; Scala, Luca; Chiampan, Andrea; Rossi, Andrea; Zoppini, Giacomo; Lonardo, Amedeo; Arcaro, Guido; Byrne, Christopher D.; Targher, Giovanni

    2016-01-01

    Abstract Repeat hospitalization due to acute heart failure (HF) is a global public health problem that markedly impacts on health resource use. Identifying novel predictors of rehospitalization would help physicians to determine the optimal postdischarge plan for preventing HF rehospitalization. Nonalcoholic fatty liver disease (NAFLD) is an emerging risk factor for many heart diseases, including HF. We assessed whether NAFLD at hospital admission predicts 1-year all-cause rehospitalization in patients with acute HF. We enrolled all patients consecutively admitted for acute HF to our General Medicine Division, from January 2013 to April 2014, after excluding patients with acute myocardial infarction, severe heart valve diseases, malignancy, known liver diseases, and those with volume overload related to extracardiac causes. NAFLD was diagnosed by ultrasonography and exclusion of competing etiologies. The primary outcome of the study was the 1-year all-cause rehospitalization rate. Among the 107 patients enrolled in the study, the cumulative rehospitalization rate was 12.1% at 1 month, 25.2% at 3 months, 29.9% at 6 months, and 38.3% at 1 year. Patients with NAFLD had markedly higher 1-year rehospitalization rates than those without NAFLD (58% vs 21% at 1 y; P < 0.001 by the log-rank test). Cox regression analysis revealed that NAFLD was associated with a 5.5-fold increased risk of rehospitalization (adjusted hazard ratio 5.56, 95% confidence interval 2.46–12.1, P < 0.001) after adjustment for multiple HF risk factors and potential confounders. In conclusion, NAFLD was independently associated with higher 1-year rehospitalization in patients hospitalized for acute HF. PMID:26886619

  12. Temporal Development of HF-Excited Langmuir and Ion Turbulence at Arecibo

    NASA Astrophysics Data System (ADS)

    Djuth, F. T.; DuBois, D. F.

    2015-10-01

    The Arecibo high-power, high-frequency (HF) facility and 430 MHz radar are used to examine the temporal development of the HF-induced Langmuir and ion turbulences from 1 ms to many minutes after the turn-on of the HF beam in the F region. All HF observations begin in a smooth, stratified, stable plasma. "Cold start" HF transmissions are employed to avoid remnant irregularities from prior HF transmissions. HF-excited plasma line (HFPL) and ion line echoes are used to monitor the evolution of the turbulence. In the evening/nighttime the HFPL develops in three reproducible stages. Over time scales of 0 to 10-20 ms (possibly 40 ms), the smooth plasma conditions are maintained, and the results are consistent with theoretical models of the excitation of strong Langmuir turbulence near HF reflection. This entails the initiation of the so-called "caviton production cycle." The turbulence from the parametric decay instability is detected at lower altitudes where the radar wave vector matches those of the HF-enhanced waves. The data suggests that the two processes coexist in the region in between. After ~40 ms the "overshoot process" begins and consists of a downward extension of the HFPL from the HF reflection region to heights ~1.1 km below followed by a retreat back to the reflection region. The whole overshoot process takes place over a time scale of ~3 s. Thereafter the echo remains near HF reflection for 20-90 s after HF turn-on. The HFPL echo subsequently breaks up into patches because of the formation of large-scale electron density structures in the plasma. New kinetic models indicate that suprathermal electrons excited in the plasma by, for example, caviton burn-out serve to regulate plasma turbulence in the modified ionospheric volume.

  13. Silicon/HfO2 interface: Effects of gamma irradiation

    NASA Astrophysics Data System (ADS)

    Maurya, Savita

    2016-05-01

    Quality of MOS devices is a strong function of substrate and oxide interface. In this work we have studied how gamma photon irradiation affects the interface of a 13 nm thick, atomic layer deposited hafnium dioxide deposited on silicon wafer. CV and GV measurements have been done for pristine and irradiated samples to quantify the effect of gamma photon irradiation. Gamma photon irradiation not only introduces positive charge in the oxide and at the interface of Si/HfO2 interface but also induce phase change of oxide layer. Maximum oxide capacitances are affected by gamma photon irradiation.

  14. Survey reveals nature of corrosion in HF alky units

    SciTech Connect

    Dobis, J.D. ); Clarida, D.R. ); Richert, J.P. )

    1995-03-06

    The results of a National Association of Corrosion Engineers survey of 62 HF alkylation units reveal relatively low incidence of service-related cracking of carbon steel. Hydrogen blistering, however, is prevalent, especially in the main acid circuit and overhead condensers. Based on these and other survey results, several recommendations are made to enable refiners to monitor and reduce corrosion in these special units. The paper discusses the survey results, construction materials, post-weld heat treatments, small-diameter piping, construction inspection, bolting, gaskets, block valves, maintenance practices, cracking, blistering, areas of vulnerability, and recommendations.

  15. 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.

  16. 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.

  17. 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. PMID:25758162

  18. Reduced-temperature processing and consolidation of ultra-refractory Ta4HfC5

    SciTech Connect

    Gaballa, Osama; Cook, B. A.; Russell, A. M.

    2013-04-26

    TaC, HfC, and WC powders were subjected to high-energy milling and hot pressing to produce Ta4HfC5, a composite of Ta(4)HfC5 + 30 vol.% WC, and a composite of Ta4HfC5 + 50 vol.% WC. Sub-micron powders were examined after four different milling intervals prior to hot pressing. XRD was used to verify proper phase formation. SEM, relative density, and hardness measurements were used to examine the resulting phases. Hot pressed compacts of Ta4HfC5 showed densification as high as 98.6% along with Vickers hardness values of 21.4 GPa. Similarly, Ta4HfC5 + 30 vol.% WC exhibited 99% densification with a Vickers hardness of 22.5 GPa. These levels of densification were achieved at 1500 degrees C, which is lower than any previously reported sintering temperature for Ta4HfC5. Microhardness values measured in this study were higher than those previously reported for Ta4HfC5. The WC additions to Ta4HfC5 were found to improve densification and increase microhardness. (C) 2013 Elsevier Ltd. All rights reserved.

  19. Characterization of nanostructured HfO2 films using Perturbed Angular Correlation (PAC) technique

    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.; Redondo, L. M.; Mestnik-Filho, J.; Saxena, R. N.; Soares, J. C.

    2010-06-01

    The hyperfine field at 181Ta lattice sites in nanostructured HfO2 thin films was studied by the Perturbed Angular Correlation (PAC) technique. Thin oxide films were deposited by Electron Beam Evaporation on a silicon substrate. The thickness of the films was ~100 nm and ~250 nm. Radioactive 181Hf nuclei were produced by neutron activation of the film samples in the Brazilian Research Reactor (IPEN IEA-R1) by the reaction 180Hf(n, γ)181Hf. PAC measurements were carried out after annealing at 1473 K. The PAC technique allows the determination of the electric field gradient (EFG) at the probe sites.

  20. Electron beam induced local crystallization of HfO2 nanopores for biosensing applications

    PubMed Central

    Shim, Jiwook; Rivera, Jose; Bashir, Rashid

    2013-01-01

    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. PMID:23945603

  1. 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.

  2. 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

  3. Lu-Hf total-rock age for the Amîtsoq gneisses, West Greenland

    USGS Publications Warehouse

    Pettingill, H.S.; Patchett, P.J.

    1981-01-01

    Lu-Hf total-rock data for the Amîtsoq gneisses of West Greenland yield an age of 3.55±0.22Gy(2σ), based on the decay constant λ176Lu=1.96×10−11y−1, and an initial176Hf/177Hf ratio of 0.280482±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 Gy, zircons from two of the samples have remained on the total-rock line, and define points close to the initial Hf ratio. The initial176Hf/177Hf lies close to a chondritic Hf isotopic evolution curve from 4.55 Gy to present. This is consistent with the igneous precursors to the Amîtsoq gneisses having been derived from the mantle at or shortly before 3.6 Gy. Anomalous relationships between Hf concentration and the176Lu/177Hf ratio may suggest that trace element abundances in the Amîtsoq gneisses are partly controlled by processes related to metamorphism.

  4. Electron beam induced local crystallization of HfO2 nanopores for biosensing applications.

    PubMed

    Shim, Jiwook; Rivera, Jose A; Bashir, Rashid

    2013-11-21

    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.

  5. 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.

  6. 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.

  7. 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.

  8. Cathodoluminescence guided zircon Hf isotope depth profiling: Mobilization of the Lu-Hf system during (U)HP rock exhumation in the Woodlark Rift, Papua New Guinea

    NASA Astrophysics Data System (ADS)

    Zirakparvar, N. A.

    2015-04-01

    Cathodoluminescence image guided Hf isotope depth profiling by laser ablation of zircons from two quartzofeldspathic host gneisses constrains the Lu-Hf system's behavior during rapid exhumation of (U)HP rocks in the Woodlark Rift, Papua New Guinea. Investigation of the depth profiling technique in individual and composite zircon standards demonstrates that it is possible to resolve ~ 8 μm thick domains in which εHf(present) differs by as little as 4 units. In a metasedimentary gneiss, 2.89 ± 0.29 Ma zircon overgrowths on Cretaceous aged inherited cores have radiogenic εHf(present) indicating growth in a medium that was originally in equilibrium with garnet undergoing recrystallization (the 'garnet effect' of Zheng et al., 2005). In a separate gneiss sample that originated as an exhumation related anatectic melt, 3.66 ± 0.13 Ma zircons lacking inheritance contain sub-domains that differ from each other by > 15 εHf(present). Some of these sub-domains are radiogenic and can be explained by the 'garnet effect', whereas others also contain highly elevated Lu and Yb in addition to their radiogenic Hf compositions, thus necessitating a medium derived from the complete breakdown of garnet. Zircons in this sample also contain non-radiogenic sub-domains that grew in the presence of Hf mobilized from the surrounding rocks of the subducted and metamorphosed remnants of the Australian continental margin. The results confirm that rapid exhumation of (U)HP rocks can result in the following: 1) transmission of radiogenic Hf (and sometimes Lu and the other HREE) from garnet bearing mafic lithologies into the quartzofeldspathic gneisses, and 2) mobilization and transport of unradiogenic Hf present within the quartzofeldspathic remnants of subducted continental crust.

  9. 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

  10. 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.

  11. Microstructure And Oxidation Properties Of Laser Clad Ni70AL20Cr7Hf3 Alloys With Extended Solid Solution Of Hf

    NASA Astrophysics Data System (ADS)

    Mazumder, J.; Sircar, S.; Ribaudo, C.; Kar, A.,

    1989-01-01

    Alloys coatings for superalloys for improved higher temperature (1200°C) service life under aggressive atmospheres are of great interest at present. There is a general consensus that addition of rare earths such as hafnium (Hf) to these alloys has a pronounced effect on the oxidation resistance properties at high temperatures. In situ laser cladding technique was used to produce Ni-Al-Cr-Hf alloys with extended solid solution of Hf in a near stoichiometric Ni3Al matrix. A 10 kW CW CO2 laser was used in conjunction with a screw-feed powder dispenser to perform the in situ cladding process.

  12. 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

  13. Resonance Ionization Instability in HF and Microwave Discharges

    NASA Astrophysics Data System (ADS)

    Dvinin, Sergey; Dovzhenko, Vitaliy

    2013-09-01

    For the first time ionization instability of HF plasma has been described in. Later it has been shown that in the spatially limited low pressure microwave discharge the given instability leads not only to change plasma structure, but to appearance of resonances at electron densities, when the size of plasma becomes multiple to some number of half waves of the standing surface wave, exciting on plasma boundary. Evolution of electron density perturbation is defined by two processes - negative feedback owing to a total current continuity (as in striations) and positive one due to excitation of a wave, which is close to a resonance. In the given work the theory has been improved with accounting of both processes that has allowed to reach better coincidence with experiment. In addition, the general theory of ionization instability has been developed. Application of the model to CCP HF (100 MHz and higher) discharge with large electrodes has shown that excitation of the instability accompanied by surface waves, propagating along plasma-sheath-electrodes interface, is possible.

  14. Multianode Photomultiplier Testing for 2013 CMS Hadronic Forward (HF) Upgrades

    NASA Astrophysics Data System (ADS)

    Funk, Garrett; Jia, Zhe; Onel, Yasar

    2012-03-01

    The Hadronic Forward (HF) section of the Compact Muon Solenoid, a detector at the Large Hadron Collider at CERN, will undergo various upgrades in 2013. HF requires photomultiplier tubes (PMTs) to detect the energy signatures of hadronic collisions. The University of Iowa High Energy Physics group is responsible for testing new PMTs for the upgrade. These tests provide seven different operational parameters that will be used for calibration and quality control before installation. The dark current test checks the noise generated by the PMTs at different voltages when there is no light source. The after pulse test measures the degradation of the vacuum chamber of each PMT as it relates to pulse noise. The gain test measures the degree of amplification provided by the PMT. This is the most vital test, as it allows for the reconstruction of the energies observed by the PMT. The surface non-uniformity test checks the active face of the PMTs for signal uniformity and ``hot spot'' sensitivity to light. The timing test observes the PMT's reading and recovery speed. The linearity test measures the tube's output under varying levels of light. The double pulse test checks the linearity of the PMT with two signals occurring 25 nanoseconds apart.

  15. Concerted hydrogen atom exchange between three HF molecules

    NASA Technical Reports Server (NTRS)

    Komornicki, Andrew; Dixon, David A.; Taylor, Peter R.

    1992-01-01

    We have investigated the termolecular reaction involving concerted hydrogen exchange between three HF molecules, with particular emphasis on the effects of correlation at the various stationary points along the reaction. Using an extended basis, we have located the geometries of the stable hydrogen-bonded trimer, which is of C(sub 3h) symmetry, and the transition state for hydrogen exchange, which is of D(sub 3h) symmetry. The energies of the exchange reation were then evaluated at the correlated level, using a large atomic natural orbital basis and correlating all valence electrons. Several correlation treatments were used, namely, configration interaction with single and double excitations, coupled-pair functional, and coupled-cluster methods. We are thus able to measure the effect of accounting for size-extensivity. Zero-point corrections to the correlated level energetics were determined using analytic second derivative techniques at the SCF level. Our best calculations, which include the effects of connected triple excitations in the coupled-cluster procedure, indicate that the trimer is bound by 9 +/- 1 kcal/mol relative to three separate monomers, in excellent agreement with previous estimates. The barrier to concerted hydrogen exchange is 15 kcal/mol above the trimer, or only 4.7 kcal/mol above three separated monomers. Thus the barrier to hydrogen exchange between HF molecules via this termolecular process is very low.

  16. 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.

  17. Identification of triaxial strongly deformed band in {sup 168}Hf.

    SciTech Connect

    Yadav, R. B.; Ma, W. C.; Hagemann, G. B.; Bengtsson, R.; Ryde, H.; Carpenter, M. P.; Janssens, R. V. F.; Khoo, T. L.; Kondev, F. G.; Lauritsen, T.; Lister, C. J.; Mississippi State Univ.; Niels Bohr Inst.; Lund Inst. of Tech.; Lund. Univ.; Univ. di Milano; Univ. of Bonn; U.S. Naval Academy; Univ. of Oslo; Univ. of Tennessee

    2008-01-01

    Possible decay pathways associated with three candidates for triaxial strongly deformed (TSD) bands in {sup 168}Hf have been investigated. The spin and excitation energy of the strongest band, TSD1, were determined approximately based on {gamma}-ray coincidence relationships. Discrete links were established for the second band. The overall agreement between the observed properties of the bands and cranking calculations using the ULTIMATE CRANKER code provides strong support for an interpretation where band TSD1 is associated with a TSD minimum, ({var_epsilon}{sub 2},{gamma}) {approx} (0.43,20{sup o}), involving the {pi}(i{sub 13/2}){sup 2} and the {nu}(j{sub 15/2}) high-j orbitals. This constitutes the first identification of a TSD band in Hf isotopes, which has been long-predicted by theoretical studies. The second band is understood as being associated with a near-prolate shape and a deformation enhanced with respect to the normal deformed bands. It is proposed to be built on the {pi}(i{sub 13/2}h{sub 9/2}) {nu}(i{sub 13/2}){sup 2} configuration.

  18. Recent observations of HF and HCl in the upper stratosphere

    NASA Technical Reports Server (NTRS)

    Zander, R.

    1981-01-01

    Concentrations of gas phase hydrofluoric acid and hydrochloric acid have been determined in the upper stratosphere from near-infrared solar spectra recorded in the course of balloon flights from Palestine, Texas, in October 1978 and in September 1979. The average mixing ratios for HF deduced respectively from these flights are (4.8 plus or minus .3) x 10 to the -10th ppv above 30.3km and (6.2 plus or minus .5) x 10 to the -10th ppv above 36.8km. This observed difference is ascribed to an increase in the HF concentration out to at least 37km. The HCl mixing ratios deduced from the 1978 flight yield (4.5 plus or minus .6) x 10 to the -10th ppv at 21.7km, (7.5 plus or minus .7) x 10 to the -10th ppv at 27.5 km and (2.1 plus or minus .4) x 10 to the -9th ppv above 30.5km. Observations in 1979 imply an average HCl mixing ratio above 36.8km of (2.4 plus or minus .4) x 10 to the -9th ppv. Our data do not indicate a measurable temporal trend of the HCl concentration above 30km.

  19. 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.

  20. 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

  1. 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

  2. Development of an obstetric vital sign alert to improve outcomes in acute care obstetrics.

    PubMed

    Behling, Diana J; Renaud, Michelle

    2015-01-01

    Maternal morbidity and mortality is a national health problem. Causal analysis of near-miss and actual serious patient safety events, including those resulting in maternal death, within obstetric units often highlights a failure to promptly recognize and treat women who were exhibiting signs of decompensation/deterioration. The Obstetric Vital Sign Alert (OBVSA) is an early warning tool that leverages discrete data points in the electronic health record, calculating a risk score that is displayed as a visual cue for acute care obstetric staff. When studied in a cohort of women with postpartum hemorrhage, use of the OBVSA reduced symptom-to-response time and intervention time, as well as key process and outcome measures.

  3. 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.

  4. Evolution of E 2 transition strength in deformed hafnium isotopes from new measurements on 172Hf,174Hf, and 176Hf

    NASA Astrophysics Data System (ADS)

    Rudigier, M.; Nomura, K.; Dannhoff, M.; Gerst, R.-B.; Jolie, J.; Saed-Samii, N.; Stegemann, S.; Régis, J.-M.; Robledo, L. M.; Rodríguez-Guzmán, R.; Blazhev, A.; Fransen, Ch.; Warr, N.; Zell, K. O.

    2015-04-01

    Background: The available data for E 2 transition strengths in the region between neutron-deficient hafnium and platinum isotopes are far from complete. More and precise data are needed to enhance the picture of structure evolution in this region and to test state-of-the-art nuclear models. In a simple model, the maximum collectivity is expected at the middle of the major shell. However, for actual nuclei, particularly in heavy-mass regions, which should be highly complex, this picture may no longer be the case, and one should use a more realistic nuclear-structure model. We address this point by studying the spectroscopy of Hf as a representative case. Purpose: We remeasure the 21+ half-lives of 172,174,176Hf, for which there is some disagreement in the literature. The main goal is to measure, for the first time, the half-lives of higher-lying states of the rotational band. The new results are compared to a theoretical calculation for absolute transition strengths. Method: The half-lives were measured using γ -γ and conversion-electron-γ delayed coincidences with the fast timing method. For the determination of half-lives in the picosecond region, the generalized centroid difference method was applied. For the theoretical calculation of the spectroscopic properties, the interacting boson model is employed, whose Hamiltonian is determined based on microscopic energy-density functional calculations. Results: The measured 21+ half-lives disagree with results from earlier γ -γ fast timing measurements, but are in agreement with data from Coulomb excitation experiments and other methods. Half-lives of the 41+ and 61+ states were measured, as well as a lower limit for the 81+ states. Conclusions: This work shows the importance of a mass-dependent effective boson charge in the interacting boson model for the description of E 2 transition rates in chains of nuclei. It encourages further studies of the microscopic origin of this mass dependence. New experimental

  5. Levosimendan vs. dobutamine: outcomes for acute heart failure patients on β-blockers in SURVIVE†

    PubMed Central

    Mebazaa, Alexandre; Nieminen, Markku S.; Filippatos, Gerasimos S.; Cleland, John G.; Salon, Jeffrey E.; Thakkar, Roopal; Padley, Robert J.; Huang, Bidan; Cohen-Solal, Alain

    2009-01-01

    Aims Many chronic heart failure (CHF) patients take β-blockers. When such patients are hospitalized for decompensation, it remains unclear how ongoing β-blocker treatment will affect outcomes of acute inotrope therapy. We aimed to assess outcomes of SURVIVE patients who were on β-blocker therapy before receiving a single intravenous infusion of levosimendan or dobutamine. Methods and results Cox proportional hazard regression revealed all-cause mortality benefits of levosimendan treatment over dobutamine when the SURVIVE population was stratified according to baseline presence/absence of CHF history and use/non-use of β-blocker treatment at baseline. All-cause mortality was lower in the CHF/levosimendan group than in the CHF/dobutamine group, showing treatment differences by hazard ratio (HR) at days 5 (3.4 vs. 5.8%; HR, 0.58, CI 0.33–1.01, P = 0.05) and 14 (7.0 vs. 10.3%; HR, 0.67, CI 0.45–0.99, P = 0.045). For patients who used β-blockers (n = 669), mortality was significantly lower for levosimendan than dobutamine at day 5 (1.5 vs. 5.1% deaths; HR, 0.29; CI 0.11–0.78, P = 0.01). Conclusion Levosimendan may be better than dobutamine for treating patients with a history of CHF or those on β-blocker therapy when they are hospitalized with acute decompensations. These findings are preliminary but important for planning future studies. PMID:19158152

  6. 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.

  7. Measurement of thermal neutron cross-sections and resonance integrals for 164Dy(n,γ) 165Dy and 180Hf(n,γ) 181Hf reactions

    NASA Astrophysics Data System (ADS)

    Cho, Hyun-Je; Kobayashi, Katsuhei; Yamamoto, Shuji; Seo, Kyung-Won; Hwang, Han Yull; Nha, Sang Kyun; Ko, Seung Kook

    2001-04-01

    The thermal neutron cross-sections for the 164Dy(n,γ) 165Dy and the 180Hf(n,γ) 181Hf reactions have been measured by the activation method at the heavy water thermal neutron facility of the Kyoto University Reactor, KUR. The results measured at 0.0253 eV are 2656±98 b for the 164Dy(n,γ) 165Dy reaction and 13.04±0.47 b for the 180Hf(n,γ) 181Hf reaction, respectively. The results have been obtained relative to the reference value of 98.65±0.09 b for the 197Au(n,γ) 198Au reaction. For dysprosium, most of the experimental data and the evaluated ones in ENDF/B-VI and JEF-2.2 are in good agreement with the present value. For hafnium, the previous measurements and the evaluated ones in ENDF/B-VI and JENDL-3.2 are in good agreement with the present result. The resonance integrals for the 164Dy(n,γ) 165Dy and the 180Hf(n,γ) 181Hf reactions have also been measured relative to the reference value of 1550±28 b for the 197Au(n,γ) 198Au reaction using a 1/ E standard neutron spectrum field of the Kinki University Reactor, UTR-KINKI. The present resonance integral for the 164Dy(n,γ) 165Dy reaction is 649±24 b, and the existing experimental and the evaluated data are distributed from 335 to 820 b. The present result for the 180Hf(n,γ) 181Hf reaction is 32.4±1.2 b, and most of the previous measurements and the evaluated values are close to the present measurement. Gryntakis et al. reported the resonance integrals for both reactions, whose results were also in good agreement with the measurements.

  8. Structural characterization of Nd-doped Hf-zirconolite Ca 1-xNd xHfTi 2-xAl xO 7 ceramics

    NASA Astrophysics Data System (ADS)

    Caurant, Daniel; Loiseau, Pascal; Bardez, Isabelle

    2010-12-01

    Because of its high incorporation capacity and of the high thermal neutron capture cross-section of hafnium, Hf-zirconolite (CaHfTi 2O 7) ceramic can be envisaged as a potential waste form for minor actinides (Np, Am, Cm) and plutonium immobilization. In this work, Nd-doped Hf-zirconolite Ca 1-xNd xHfTi 2-xAl xO 7 ( x = 0; 0.01 and 0.2) ceramics have been prepared by solid state reaction. Neodymium has been used as trivalent actinide surrogate. The ceramic samples structure has been studied by X-ray diffraction and refined by the Rietveld method. This revealed that Nd 3+ ions only enter the Ca site, whereas part of Hf 4+ ions substitute titanium into Ti(1) sites and Al 3+ ions mainly occupy the Ti(2) split sites and Ti(3) sites of the zirconolite structure. Using various spectroscopic techniques (electron spin resonance, optical absorption and fluorescence), the environment of Nd 3+ cations in Hf-zirconolite has been studied and compared with that of Nd 3+ cations in Zr-zirconolite (CaZrTi 2O 7). Different local environments of Nd 3+ cations have been detected in Hf-zirconolite that can be attributed to the existence of an important disorder around Nd in the Ca site probably due to the statistical occupancy of the next nearest cationic site of neodymium (a split Ti site) by Ti 4+, Al 3+ cations and vacancies. No significant differences were observed concerning Nd 3+ cations environment and distribution in Hf- and Zr-zirconolite ceramics.

  9. 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

  10. Diagnostic implications of soluble triggering receptor expressed on myeloid cells-1 in patients with acute respiratory distress syndrome and abdominal diseases: a preliminary observational study

    PubMed Central

    2011-01-01

    Introduction Patients admitted to the intensive care unit (ICU) because of acute or decompensated chronic abdominal disease and acute respiratory failure need to have the potential infection diagnosed as well as its site (pulmonary or abdominal). For this purpose, we measured soluble triggering receptor expression on myeloid cells-1 (sTREM-1) in alveolar and peritoneal fluid. Methods Consecutive patients (n = 21) with acute or decompensated chronic abdominal disease and acute respiratory failure were included. sTREM was measured in alveolar (A-sTREM) and peritoneal (P-sTREM) fluids. Results An infection was diagnosed in all patients. Nine patients had a lung infection (without abdominal infection), 5 had an abdominal infection (without lung infection) and seven had both infections. A-sTREM was higher in the patients with pneumonia compared to those without pneumonia (1963 ng/ml (1010-3129) vs. 862 ng/ml (333-1011); P 0.019). Patients with abdominal infection had an increase in the P-sTREM compared to patients without abdominal infection (1941 ng/ml (1088-3370) vs. 305 ng/ml (288-459); P < 0.001). A cut-off point of 900 pg/ml of A-sTREM-1 had a sensitivity of 81% and a specificity of 80% (NPV 57%; PPV 93%, AUC 0.775) for the diagnosis of pneumonia. In abdominal infections, a cut-off point for P-sTREM of 900 pg/ml had the best results (sensitivity 92%; specificity 100%; NPV 90%, PPV 100%, AUC = 0.903). Conclusions sTREM-1 measured in alveolar and peritoneal fluids is useful in assessing pulmonary and peritoneal infection in critical-state patients-A-sTREM having the capacity to discriminate between a pulmonary and an extra-pulmonary infection in the context of acute respiratory failure. PMID:21294874

  11. Acute and Chronic Fetal Anemia as a Result of Fetomaternal Hemorrhage

    PubMed Central

    Swanson, Tara

    2014-01-01

    Introduction. Fetomaternal hemorrhage represents a transfer of fetal blood to the maternal circulation. Although many etiologies have been described, most causes of fetomaternal hemorrhage remain unidentified. The differentiation between acute and chronic fetomaternal hemorrhage may be accomplished antenatally and may influence perinatal management. Case. A 36-year-old gravida 6 para 3 presented at 37 and 5/7 completed gestational weeks with ultrasound findings suggestive of chronic fetal anemia such as right ventricular enlargement, diminished cerebral vascular resistance, and elevated middle cerebral artery end-diastolic velocity. On the other hand, signs of acute fetal decompensation such as deterioration of the fetal heart tracing, diminished biophysical score, decreased cord pH, and increased cord base deficit were noted. Following delivery, the neonate's initial hemoglobin was 4.0 g/dL and the maternal KB ratio was 0.015 indicative of a significant fetomaternal hemorrhage. Discussion. One should consider FMH as part of the differential diagnosis for fetal or immediate neonatal anemia. We describe a unique case of FMH that demonstrated both acute and chronic clinical features. It is our hope that this case will assist practitioners in differentiating acute FMH that may require emergent delivery from chronic FMH which may be able to be expectantly managed. PMID:24804127

  12. Risk-Adapted Management of Acute Pulmonary Embolism: Recent Evidence, New Guidelines

    PubMed Central

    Käberich, Anja; Wärntges, Simone; Konstantinides, Stavros

    2014-01-01

    Venous thromboembolism (VTE), the third most frequent acute cardiovascular syndrome, may cause life-threatening complications and imposes a substantial socio-economic burden. During the past years, several landmark trials paved the way towards novel strategies in acute and long-term management of patients with acute pulmonary embolism (PE). Risk stratification is increasingly recognized as a cornerstone for an adequate diagnostic and therapeutic management of the highly heterogeneous population of patients with acute PE. Recently published European Guidelines emphasize the importance of clinical prediction rules in combination with imaging procedures (assessment of right ventricular function) and laboratory biomarkers (indicative of myocardial stress or injury) for identification of normotensive PE patients at intermediate risk for an adverse short-term outcome. In this patient group, systemic full-dose thrombolysis was associated with a significantly increased risk of intracranial bleeding, a complication which discourages its clinical application unless hemodynamic decompensation occurs. A large-scale clinical trial program evaluating new oral anticoagulants in the initial and long-term treatment of venous thromboembolism showed at least comparable efficacy and presumably increased safety of these drugs compared to the current standard treatment. Research is continuing on catheter-directed, ultrasound-assisted, local, low-dose thrombolysis in the management of intermediate-risk PE. PMID:25386356

  13. Loop diuretics in acute heart failure: beyond the decongestive relief for the kidney.

    PubMed

    Palazzuoli, Alberto; Ruocco, Gaetano; Ronco, Claudio; McCullough, Peter A

    2015-09-03

    Current goals in the acute treatment of heart failure are focused on pulmonary and systemic decongestion with loop diuretics as the cornerstone of therapy. Despite rapid relief of symptoms in patients with acute decompensated heart failure, after intravenous use of loop diuretics, the use of these agents has been consistently associated with adverse events, including hypokalemia, azotemia, hypotension, and increased mortality. Two recent randomized trials have shown that continuous infusions of loop diuretics did not offer benefit but were associated with adverse events, including hyponatremia, prolonged hospital stay, and increased rate of readmissions. This is probably due to the limitations of congestion evaluation as well as to the deleterious effects linked to drug administration, particularly at higher dosage. The impaired renal function often associated with this treatment is not extensively explored and could deserve more specific studies. Several questions remain to be answered about the best diuretic modality administration, global clinical impact during acute and post-discharge period, and the role of renal function deterioration during treatment. Thus, if loop diuretics are a necessary part of the treatment for acute heart failure, then there must be an approach that allows personalization of therapy for optimal benefit and avoidance of adverse events.

  14. [Acute diarrhea].

    PubMed

    Burgmann, Konstantin; Schoepfer, Alain

    2014-09-01

    Diarrhea, defined as three or more loose or watery stools per day, represents a frequent problem in outpatients as well as inpatients. As most of the patients with acute diarrhea show a self-limiting disease course, the main challenge for the physician is to discriminate patients for whom symptomatic therapy is sufficient from those with severe disease course and threatening complications. This review aims to provide a practical guidance for such decisions.

  15. 47 CFR 73.758 - System specifications for digitally modulated emissions in the HF broadcasting service.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... emissions in the HF broadcasting service. 73.758 Section 73.758 Telecommunication FEDERAL COMMUNICATIONS... § 73.758 System specifications for digitally modulated emissions in the HF broadcasting service. (a... digital audio broadcasting and datacasting are authorized. The RF requirements for the DRM system...

  16. 47 CFR 73.758 - System specifications for digitally modulated emissions in the HF broadcasting service.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... emissions in the HF broadcasting service. 73.758 Section 73.758 Telecommunication FEDERAL COMMUNICATIONS... § 73.758 System specifications for digitally modulated emissions in the HF broadcasting service. (a... digital audio broadcasting and datacasting are authorized. The RF requirements for the DRM system...

  17. 47 CFR 73.758 - System specifications for digitally modulated emissions in the HF broadcasting service.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... emissions in the HF broadcasting service. 73.758 Section 73.758 Telecommunication FEDERAL COMMUNICATIONS... § 73.758 System specifications for digitally modulated emissions in the HF broadcasting service. (a... digital audio broadcasting and datacasting are authorized. The RF requirements for the DRM system...

  18. Interfacial and structural properties of sputtered HfO{sub 2} layers

    SciTech Connect

    Aygun, G.; Yildiz, I.

    2009-07-01

    Magnetron sputtered HfO{sub 2} layers formed on a heated Si substrate were studied by spectroscopic ellipsometer (SE), x-ray diffraction (XRD), Fourier transform infrared (FTIR), and x-ray photoelectron spectroscopy (XPS) depth profiling techniques. The results show that the formation of a SiO{sub x} suboxide layer at the HfO{sub 2}/Si interface is unavoidable. The HfO{sub 2} thickness and suboxide formation are highly affected by the growth parameters such as sputtering power, O{sub 2}/Ar gas ratio during sputtering, sputtering time, and substrate temperature. XRD spectra show that the deposited film has (111) monoclinic phase of HfO{sub 2}, which is also supported by FTIR spectra. The atomic concentration and chemical environment of Si, Hf, and O have been measured as a function of depth starting from the surface of the sample by XPS technique. It shows that HfO{sub 2} layers of a few nanometers are formed at the top surface. Below this thin layer, Si-Si bonds are detected just before the Si suboxide layer, and then the Si substrate is reached during the depth profiling by XPS. It is clearly understood that the highly reactive sputtered Hf atoms consume some of the oxygen atoms from the underlying SiO{sub 2} to form HfO{sub 2}, leaving Si-Si bonds behind.

  19. 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.

  20. Interface properties of Ge on cubic SrHfO3 (001)

    NASA Astrophysics Data System (ADS)

    Wang, Jianli; Wang, Chenxiang; Tang, Gang; Zhang, Junting; Guo, Sandong; Han, Yujia

    2016-06-01

    High quality Ge-on-high-k oxide interface is essential to facilitate the high performance metal-oxide semiconductor field-effect transistors and monolithically integrated optoelectronics device performance. The atomic structure and electronic properties of Ge on perfect and defective (001) SrHfO3 are investigated by first-principle calculations. The amplitude of the surface rumpling for the SrO-terminated surface is much larger than that for HfO2-terminated surface, although both SrO- and HfO2-terminated surfaces are stable for a comparable range of the HfO2 chemical potential. The distance between the first and second planes compresses while that of the second and third planes expands due to the relaxation of the slab. We investigated systematically the specific adsorption sites and the atomic structure at the initial growth stage of Ge on the SrHfO3 (001) substrate. The top sites of the oxygen atoms are favorable for 1/2 (1/3) monolayer Ge adsorbate at SrO (HfO2)-terminated surface. We calculated the surface grand potential and presented the complete surface phase diagram. We also pointed out the energetically favorable interfaces among the atomic arrangements of the Ge/SrHfO3 (001) interfaces. The atomic structure and electronic properties of the intrinsic point defects were calculated and analyzed for the Ge/SrHfO3 (001) interfaces.

  1. Schirmwirkung von Hochfrequenz (HF)-Schutzkleidung: Untersuchung verschiedener Konstruktionsmerkmale

    NASA Astrophysics Data System (ADS)

    Arps, V.; Scheibe, K.

    2005-05-01

    Die Messverfahren zur Bestimmung der Schutzwirkung von HF-Schutzkleidung sind in der Norm DIN 32780-100 festgelegt. Entsprechend diesen Anforderungen wird die elektrische und magnetische Schirmdämpfung bestimmt und daraus als Maß für die Schutzwirkung die elektromagnetische Schirmdämpfung berechnet. Diese ist eine der SAR vergleichbare Größe. In diesem Beitrag werden die Einflüsse verschiedener Konstruktionsmerkmale von HF-Schutzanzügen auf die elektromagnetische Schirmdämpfung untersucht. Zu diesen gehören die nach MIL STD 285 vermessene elektrische Schirmdämpfung der verwendeten Gewebe. Weiter werden verschiedene Teilbereiche der HF-Schutzkleidung auf ihre Schutzwirkung untersucht. Der Schwerpunkt liegt hierbei auf der Fragestellung inwieweit Verschlüsse, Reißverschlüsse oder leitfähiges Klettband, die Schutzwirkung beeinträchtigen. Zu diesem Zweck werden zwei Schutzanzüge unterschiedlicher Konstruktion vergleichend vermessen. Es handelt sich dabei um einen bereits im Handel befindlichen und entsprechend der Norm zertifizierten Anzug und einen neuen Prototyp, welcher nach verschiedenen Gesichtspunkten optimiert wurde. Schwachstellen der Konstruktion werden herausgearbeitet und Ansatzpunkte für weitere Verbesserungen erarbeitet. The measuring methods for determining the shielding effectiveness of radiofrequency (RF)-protective clothing are defined in German Standard DIN 32780-100. According to this standard, both the electric and the magnetic shielding effectiveness are measured in order to calculate the electromagnetic shielding effectiveness. The electromagnetic shielding effectiveness is an adequate quality criterion for the degree of protection and also compares well with the Specific Absorption Rate (SAR). In this article, the impact of different design features on the electromagnetic shielding effectiveness is analyzed. The electric shielding effectiveness of the used shielding materials is measured according to MIL STD 285 and thereupon

  2. Comparison of HfO2 films grown by atomic layer deposition using HfCl4 and H2O or O3 as the oxidant

    NASA Astrophysics Data System (ADS)

    Park, Hong Bae; Cho, Moonju; Park, Jaehoo; Lee, Suk Woo; Hwang, Cheol Seong; Kim, Jong-Pyo; Lee, Jong-Ho; Lee, Nae-In; Kang, Ho-Kyu; Lee, Jong-Cheol; Oh, Se-Jung

    2003-09-01

    HfO2 gate dielectric thin-films were deposited on Si wafers using an atomic-layer deposition (ALD) technique with HfCl4 and either H2O or O3 as the precursor and oxidant, respectively. Although the ALD reactions using either H2O or O3 were successfully confirmed at a deposition temperature of 300 °C, the structural and electrical properties of the HfO2 films grown using the two oxidants were quite different. The stronger oxidation power of the O3 compared to H2O increased the oxygen concentration in the HfO2 film and the rate of interfacial SiO2 formation even at the as-deposited state. Because of the larger oxygen concentration, the decrease in the capacitance density of the film grown with O3 after rapid thermal annealing at 750 °C under N2 atmosphere was slightly larger than that of the HfO2 film grown with H2O. Apart from this weakness, all the other electrical properties, including the fixed charge density, the interface trap density, the leakage current density and the hysteresis in the capacitance-voltage plot of the film grown with O3 were superior to those of the film grown with H2O. Therefore, O3 appears to be a better oxidant for the HfO2 film growth using the ALD method.

  3. 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.

  4. Crystal structure of Si-doped HfO{sub 2}

    SciTech Connect

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

    2014-01-21

    Si-doped HfO{sub 2} 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 HfO{sub 2} was determined as less than 9 at. %. A second phase was identified as Cristobalite (SiO{sub 2}) rather than HfSiO{sub 4}, the latter of which would be expected from existing SiO{sub 2}-HfO{sub 2} phase diagrams. Crystallographic refinement with increased Si-dopant concentration in monoclinic HfO{sub 2} 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.

  5. Effect of hydrofluoric acid (HF) concentration to pores size diameter of silicon membrane.

    PubMed

    Burham, Norhafizah; Hamzah, Azrul Azlan; Majlis, Burhanuddin Yeop

    2014-01-01

    This paper studies parameters which affect the pore size diameter of a silicon membrane. Electrochemical etching is performed in characterise the parameter involved in this process. The parameter has been studied is volume ratio of hydrofluoric acid (HF) and ethanol as an electrolyte aqueous for electrochemical etch. This electrolyte aqueous solution has been mixed between HF and ethanol with volume ratio 3:7, 5:5, 7:3 and 9:1. As a result, the higher volume of HF in this electrolyte gives the smallest pore size diameter compared to the lower volume of HF. These samples have been dipped into HF and ethanol electrolyte aqueous with supplied 25 mA/cm2 current density for 20, 30, 40, and 50 minutes. The samples will inspect under Scanning Electron Microscope (SEM) to execute the pore formations on silicon membrane surface.

  6. Perturbed angular correlation study of a nanostructured HfO2 film

    NASA Astrophysics Data System (ADS)

    Pasquevich, A. F.; Cavalcante, F. H. M.; Soares, J. C.

    The hyperfine field at 181Ta lattice sites in a nanostructured Hf02 thin film was studied by the perturbed angular correlation (PAC) technique. The thin oxide film was deposited by pulsed laser ablation on a silicon substrate kept at 673 K. The thickness was about 25 nm. The radioactive 181Hf ions were produced by neutron activation of the very thin film in the Portuguese research reactor by the reaction 180Hf(n,γ)181Hf. PAC measurements were carried out at room temperature after annealing at different temperatures up to 1,473 K in air. The PAC technique allows determining the electric field gradient at the 181Ta probe sites. The 181Ta isotopes appear in the sample as disintegration product of 181 Hf.

  7. Perturbed angular correlation study of a nanostructured HfO2 film

    NASA Astrophysics Data System (ADS)

    Pasquevich, A. F.; Cavalcante, F. H. M.; Soares, J. C.

    2007-09-01

    The hyperfine field at 181Ta lattice sites in a nanostructured HfO2 thin film was studied by the perturbed angular correlation (PAC) technique. The thin oxide film was deposited by pulsed laser ablation on a silicon substrate kept at 673 K. The thickness was about 25 nm. The radioactive 181Hf ions were produced by neutron activation of the very thin film in the Portuguese research reactor by the reaction 180Hf(n, γ)181Hf. PAC measurements were carried out at room temperature after annealing at different temperatures up to 1,473 K in air. The PAC technique allows determining the electric field gradient at the 181Ta probe sites. The 181Ta isotopes appear in the sample as disintegration product of 181Hf.

  8. Synthesis of polymorph A-enriched beta zeolites in a HF-concentrated system.

    PubMed

    Zhang, Guanqun; Wang, Bingchun; Zhang, Weiping; Li, Mingrun; Tian, Zhijian

    2016-04-21

    Polymorph A-enriched beta zeolites were synthesized by employing high HF concentrations in the synthesis medium. The polymorphic compositions of the synthesized beta zeolites were determined by the complementary characterization methods (19)F NMR analysis and PXRD simulation. With a variety of SDAs, a high HF concentration (HF/SDA > 1.0) in the synthesis medium results in the A-rich feature (55-65% A) of beta zeolites, while a moderate HF concentration only results in typical beta zeolites. A systematic study on the synthesis conditions reveals the existence of a buffered system of H(+) and F(-) formed in the highly HF-concentrated medium. This buffer results in a small but continuous supply of F(-) during zeolite crystallization, in contrast to the conventional fluoride route where all F(-) are discharged all-at-once at the initial stage. PMID:26974286

  9. Directionally solidified pseudo-binary eutectics of Ni-Cr-/Hf,Zr/

    NASA Technical Reports Server (NTRS)

    Kim, Y. G.; Ashbrook, R. L.

    1975-01-01

    This report is concerned with the experimental determination of pseudo binary eutectic compositions and the directional solidification of the Ni-Cr-Hf,Zr, and Ni-Cr-Zr eutectic alloys. To determine unknown eutectics, chemical analyses were made of material bled from near eutectic ingots during incipient melting. Nominal compositions in weight per cent of Ni-18.6Cr-24.0Hf, Ni-19.6Cr-12.8Zr-2.8Hf, and Ni-19.2Cr-14.8Zr formed aligned pseudo-binary eutectic structures. The melting points were about 1270 C. The reinforcing intermetallic phases were identified as noncubic (Ni,Cr)7Hf2 and (Ni,Cr)7(Hf,Zr)2, and face centered cubic (Ni,Cr)5Zr. The volume fraction of the reinforcing phases were about 0.5.

  10. Ab initio characterization of the Mg-HF van der Waals complex.

    PubMed

    Koput, Jacek; Makarewicz, Jan

    2010-10-28

    The equilibrium structure and the three-dimensional potential energy surface of the Mg-HF van der Waals complex in its ground electronic state have been determined from accurate ab initio calculations using the coupled-cluster method, CCSD(T), in conjunction with the basis sets of triple- through quintuple-zeta quality. The core-electron correlation, high-order valence-electron correlation, and scalar relativistic effects were investigated. The Mg-HF complex was confirmed to be linear at equilibrium, with a vibrationless dissociation energy (into Mg and HF) D(e) of 280 cm(-1). The vibration-rotation energy levels of two isotopologues, (24)Mg-HF and (24)Mg-DF, were predicted using the variational method. The predicted spectroscopic constants can be useful in a further analysis of high-resolution vibration-rotation spectra of the Mg-HF complex.

  11. Shape memory effect of the Ni-Ti-Hf high temperature shape memory alloy

    SciTech Connect

    Wu, K.H.; Pu, Z.; Tseng, H.K.; Biancaniello, F.S.

    1995-11-17

    The one-way shape memory effect of the newly-developed TiNi-Hf high temperature shape memory alloys has been investigated. The results of the study show that TiNi-Hf high temperature alloys possess a relatively high shape memory effect. All the alloys, even those with an Hf content as high as 30at%, exhibit complete strain recovery behavior. However, as the Hf content increases, the fully reversible strain of the alloys decreases. The increase of the second phase as the Hf content increases is the primary reason for the deterioration of the shape memory effect and ductility. The shape memory properties also deteriorate as the deformation temperature increases.

  12. 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.

  13. Toward an european Med HF-radar coastal monitoring

    NASA Astrophysics Data System (ADS)

    Molcard, A.; Fraunie, P.

    2010-12-01

    The monitoring of coastal areas through HF radar is developping in the european Mediterranean coasts, through national and international projects. Surface current maps may be used for process studies, forecast correction through assimilation, or for practical applications in transport studies (jellyfish, oil-spill, search-and-rescue operations). Results of radar campaigns in the North-western Mediterranean (evidence of mesoscale eddy in the Gulf of Lions and identification of dynamical structures by FSLE in the Ligurian Sea) are shown, as well as techniques for current reconstruction using a single site. A new inter-regional european project started in summer 2010, regrouping 5 countries for an integrated oil-spill coastal awarness network is presented.

  14. 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.

  15. Development of HF radar inversion algorithm for spectrum estimation (HIAS)

    NASA Astrophysics Data System (ADS)

    Hisaki, Yukiharu

    2015-03-01

    A method for estimating ocean wave directional spectra using an HF (high-frequency) ocean radar was developed. This method represents the development of work conducted in previous studies. In the present method, ocean wave directional spectra are estimated on polar coordinates whose center is the radar position, while spectra are estimated on regular grids. This method can be applied to both single and multiple radar cases. The area for wave estimation is more flexible than that of the previous method. As the signal to noise (SN) ratios of Doppler spectra are critical for wave estimation, we develop a method to exclude low SN ratio Doppler spectra. The validity of the method is demonstrated by comparing results with in situ observed wave data that it would be impossible to estimate by the methods of other groups.

  16. 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.

  17. Alternatives for satellite sound broadcast systems at HF and VHF

    NASA Technical Reports Server (NTRS)

    Leroy, B. E.

    1985-01-01

    The National Aeronautics and Space Administration and the United States Information Agency (USIA) are currently engaged in a joint program to assess the technical and economic feasibility of direct sound broadcast satellite systems to meet USIA mission needs. The cooperative effort calls for a series of interrelated studies to provide the respective Agency managements with information on the potential role of direct broadcast satellites. Initial studies focused on HF propagation phenomena and broadcast coverage requirements. These studies served as the basis for parallel systems studies currently in progress. The systems studies are to provide a data base on various satellite configurations and systems concepts capable of supporting potential broadcast requirements ranging from a small fraction to a substantial addition to USIA requirements. Antenna concepts for LEO and GEO orbits are briefly described.

  18. Josephson parametric amplifiers for the ADMX-HF experiment

    NASA Astrophysics Data System (ADS)

    Malnou, Maxime; Palken, Daniel; Hilton, Gene; Vale, Leila; Lehnert, Konrad

    2016-03-01

    Dark matter search in the ADMX-HF experiment aims at detecting power generated by the axion-photon conversion, of a few hundred of yoctowatts, in the 4 - 12 GHz band. The sensitivity of detection directly depends on the amplifier noise temperature, and therefore requires state of the art microwave amplifiers. In contrast to amplifiers with dissipation on-chip, superconducting Josephson parametric amplifiers (JPA) reach and even circumvent the quantum limit. Over the past years, we have developed JPAs fabricated with arrays of superconducting quantum interference devices. Their gain, bandwidth and tunability are particularly well suited for efficient amplification in the band of interest. In this talk we will present numerical modeling of the behavior of our amplifiers, along with the first results from new designs that cover the 4-12 GHz band. Finally, we will present the ongoing work to increase the gain-bandwidth product and gain stability of our amplifiers.

  19. 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.

  20. 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.

  1. Integrated Omic Analysis of a Guinea Pig Model of Heart Failure and Sudden Cardiac Death.

    PubMed

    Foster, D Brian; Liu, Ting; Kammers, Kai; O'Meally, Robert; Yang, Ni; Papanicolaou, Kyriakos N; Talbot, C Conover; Cole, Robert N; O'Rourke, Brian

    2016-09-01

    Here, we examine key regulatory pathways underlying the transition from compensated hypertrophy (HYP) to decompensated heart failure (HF) and sudden cardiac death (SCD) in a guinea pig pressure-overload model by integrated multiome analysis. Relative protein abundances from sham-operated HYP and HF hearts were assessed by iTRAQ LC-MS/MS. Metabolites were quantified by LC-MS/MS or GC-MS. Transcriptome profiles were obtained using mRNA microarrays. The guinea pig HF proteome exhibited classic biosignatures of cardiac HYP, left ventricular dysfunction, fibrosis, inflammation, and extravasation. Fatty acid metabolism, mitochondrial transcription/translation factors, antioxidant enzymes, and other mitochondrial procsses, were downregulated in HF but not HYP. Proteins upregulated in HF implicate extracellular matrix remodeling, cytoskeletal remodeling, and acute phase inflammation markers. Among metabolites, acylcarnitines were downregulated in HYP and fatty acids accumulated in HF. The correlation of transcript and protein changes in HF was weak (R(2) = 0.23), suggesting post-transcriptional gene regulation in HF. Proteome/metabolome integration indicated metabolic bottlenecks in fatty acyl-CoA processing by carnitine palmitoyl transferase (CPT1B) as well as TCA cycle inhibition. On the basis of these findings, we present a model of cardiac decompensation involving impaired nuclear integration of Ca(2+) and cyclic nucleotide signals that are coupled to mitochondrial metabolic and antioxidant defects through the CREB/PGC1α transcriptional axis.

  2. Integrated Omic Analysis of a Guinea Pig Model of Heart Failure and Sudden Cardiac Death.

    PubMed

    Foster, D Brian; Liu, Ting; Kammers, Kai; O'Meally, Robert; Yang, Ni; Papanicolaou, Kyriakos N; Talbot, C Conover; Cole, Robert N; O'Rourke, Brian

    2016-09-01

    Here, we examine key regulatory pathways underlying the transition from compensated hypertrophy (HYP) to decompensated heart failure (HF) and sudden cardiac death (SCD) in a guinea pig pressure-overload model by integrated multiome analysis. Relative protein abundances from sham-operated HYP and HF hearts were assessed by iTRAQ LC-MS/MS. Metabolites were quantified by LC-MS/MS or GC-MS. Transcriptome profiles were obtained using mRNA microarrays. The guinea pig HF proteome exhibited classic biosignatures of cardiac HYP, left ventricular dysfunction, fibrosis, inflammation, and extravasation. Fatty acid metabolism, mitochondrial transcription/translation factors, antioxidant enzymes, and other mitochondrial procsses, were downregulated in HF but not HYP. Proteins upregulated in HF implicate extracellular matrix remodeling, cytoskeletal remodeling, and acute phase inflammation markers. Among metabolites, acylcarnitines were downregulated in HYP and fatty acids accumulated in HF. The correlation of transcript and protein changes in HF was weak (R(2) = 0.23), suggesting post-transcriptional gene regulation in HF. Proteome/metabolome integration indicated metabolic bottlenecks in fatty acyl-CoA processing by carnitine palmitoyl transferase (CPT1B) as well as TCA cycle inhibition. On the basis of these findings, we present a model of cardiac decompensation involving impaired nuclear integration of Ca(2+) and cyclic nucleotide signals that are coupled to mitochondrial metabolic and antioxidant defects through the CREB/PGC1α transcriptional axis. PMID:27399916

  3. 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

  4. 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

  5. Hf and Nd isotopes in marine sediments: Constraints on global silicate weathering

    NASA Astrophysics Data System (ADS)

    Bayon, G.; Burton, K. W.; Soulet, G.; Vigier, N.; Dennielou, B.; Etoubleau, J.; Ponzevera, E.; German, C. R.; Nesbitt, R. W.

    2009-01-01

    The combined use of Lu-Hf and Sm-Nd isotope systems potentially offers a unique perspective for investigating continental erosion, but little is known about whether, and to what extent, the Hf-Nd isotope composition of sediments is related to silicate weathering intensity. In this study, Hf and Nd elemental and isotope data are reported for marine muds, leached Fe-oxide fractions and zircon-rich turbidite sands collected off the Congo River mouth, and from other parts of the SE Atlantic Ocean. All studied samples from the Congo fan (muds, Fe-hydroxides, sands) exhibit indistinguishable Nd isotopic composition (ɛ Nd ~ - 16), indicating that Fe-hydroxides leached from these sediments correspond to continental oxides precipitated within the Congo basin. In marked contrast, Hf isotope compositions for the same samples exhibit significant variations. Leached Fe-hydroxide fractions are characterized by ɛ Hf values (from - 1.1 to + 1.3) far more radiogenic than associated sediments (from - 7.1 to - 12.0) and turbidite sands (from - 27.2 to - 31.6). ɛ Hf values for Congo fan sediments correlate very well with Al/K (i.e. a well-known index for the intensity of chemical weathering in Central Africa). Taken together, these results indicate that (1) silicate weathering on continents leads to erosion products having very distinctive Hf isotope signatures, and (2) a direct relationship exists between ɛ Hf of secondary clay minerals and chemical weathering intensity. These results combined with data from the literature have global implications for understanding the Hf-Nd isotope variability in marine precipitates and sediments. Leached Fe-hydroxides from Congo fan sediments plot remarkably well on an extension of the 'seawater array' (i.e. the correlation defined by deep-sea Fe-Mn precipitates), providing additional support to the suggestion that the ocean Hf budget is dominated by continental inputs. Fine-grained sediments define a diffuse trend, between that for igneous

  6. 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.

  7. Right heart failure in acute respiratory distress syndrome: An unappreciated albeit a potential target for intervention in the management of the disease.

    PubMed

    Biswas, Abhishek

    2015-10-01

    Mortality from acute respiratory distress syndrome (ARDS) has gone down recently. In spite of this trend, the absolute numbers continue to be high even with improvements in ventilator strategies and a better understanding of fluid management with this disease. A possible reason for this could be an under-recognized involvement of the pulmonary vasculature and the right side of the heart in ARDS. The right heart is not designed to function under situations leading to acute elevations in afterload as seen in ARDS, and hence it decompensates. This brief review focuses on the magnitude of the problem, its detection in the intensive care unit, and recognizes the beneficial effect of prone-positioning on the pulmonary vasculature and right heart. PMID:26628826

  8. SY 05-3 HYPERTENSION AND BP EFFECT IN HF: PARADOX OR PHENOMENON?

    PubMed

    Yoo, ByungSu

    2016-09-01

    Hypertension is the most common risk factor for systolic and diastolic heart failure. Based on population-attributable risks, hypertension has the greatest impact on the development of heart failure, accounting for 39% of HF events in men and 59% in women. Higher blood pressure, longer duration of hypertension and older age are associated with higher incidence of heart failure however, long term control of hypertension reduces the risk of heart failure. Thus current guideline pointed the hypertension as the single most important modifiable risk factor for heart failure. Although a number of studies have done regarding the hypertension and the development of heart failure, the prognostic value of the hypertension in established systolic heart failure setting has not been well evaluated. Since the hypertension is associated with other cardiovascular risk factors including diabetes and chronic kidney disease, the patients with preexisting hypertension might have worse prognosis. On the contrary, higher dosage and more combinations of heart failure medication which have mortality benefits could be tolerable in patients with hypertension.Admission systolic blood pressure is known as a predictor of mortality in previous studies. However the initial blood pressure on admission could be easily affected by high sympathetic tone rather than the preexisting hypertension. The concept of "reactive hypertension" which means functional cardiac reserve in acute physiologic stress was applied to explain this phenomenon. The patients with lower functional cardiac reserve have lower blood pressure even in acute stressful condition (ie, pulmonary congestion) and these patients are at higher risk of mortality. We believe the benefits of the medical treatment are more appropriate to explain the lower mortality of hypertension group. While a history of hypertension is very common in heart failure, the high blood pressure can disappear when left ventricular systolic dysfunction develops

  9. Photocurrent generation in carbon nanotube/cubic-phase HfO2 nanoparticle hybrid nanocomposites.

    PubMed

    Rauwel, Protima; Galeckas, Augustinas; Salumaa, Martin; Ducroquet, Frédérique; Rauwel, Erwan

    2016-01-01

    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

  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. Acute effect of dietary fatty acid composition on postprandial metabolism in women.

    PubMed

    Clevenger, Hui C; Kozimor, Amanda L; Paton, Chad M; Cooper, Jamie A

    2014-09-01

    The composition of fatty acids in a diet may differentially affect metabolism, thus playing a role in the development of obesity. Our aim was to study the effects of three high-fat (HF) meals with different degrees of saturation on diet-induced thermogenesis (DIT) and substrate oxidation in premenopausal women of normal weight. Fifteen healthy, normal-weight women, aged 18-35 years, participated in a randomized cross-over study, in which they consumed isocaloric HF meals (70% of energy from fat) rich in saturated fat (SFA; 40% of total energy), monounsaturated fat (MUFA; 42% of total energy) or polyunsaturated fat (PUFA; 42% of total energy). Indirect calorimetry was used to measure respiratory gases for a 5 h postprandial period. The data collected were used to determine respiratory exchange ratio for assessing substrate oxidation, as well as energy expenditure for the determination of DIT. The area under the curve for DIT following the PUFA-rich HF meal was greater than that of the SFA- or MUFA-rich HF meals [10.0 ± 0.7, 8.6 ± 0.8 and 8.9 ± 1.2 kcal (5 h)(-1) (P = 0.02) for PUFA, MUFA and SFA, respectively]. No significant difference was found in respiratory exchange ratio (0.86 ± 0.01, 0.85 ± 0.01 and 0.85 ± 0.01 for PUFA-, MUFA- and SFA-rich HF meals, respectively) or substrate utilization following the three different HF meals (12.2 ± 1.0, 11.2 ± 0.5 and 11.6 ± 0.9 g for cumulative postprandial carbohydrate oxidation following the PUFA-, MUFA- and SFA-rich HF meals, respectively; and 3.8 ± 0.4, 4.1 ± 0.2 and 4.1 ± 0.3 g for cumulative fat oxidation of the PUFA-, MUFA- and SFA-rich HF meals, respectively). In conclusion, acute ingestion of a PUFA-rich HF meal induced a greater DIT in normal-weight women compared with SFA- or MUFA-rich HF meals. No significant differences were found for substrate utilization.

  12. 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.

  13. Authigenic phases and biomass contents drive Zr, Hf and REE distributions in anoxic lake sediments

    NASA Astrophysics Data System (ADS)

    Censi, P.; Saiano, F.; Zuddas, P.; Nicosia, A.; Mazzola, S.; Raso, M.

    2013-05-01

    REE, Zr and Hf distributions in seafloor sediments collected from the hypersaline, anoxic Thetis, Kryos, Medee and Tyro deep-sea basins from the Eastern Mediterranean were determined in light of their mineralogical composition, and biomass contents. Mineralogical investigations demonstrate that all the studied sediments show a similar mineralogy. Detritic assemblages mainly consist of quartz, gypsum and calcite with Mg contents ranging from 0 to about 7%, often of a bioclastic nature. On the contrary, authigenic parageneses are formed by halite, bischofite, dolomite and calcite, with Mg contents up to 22%. Textural evidences of biological activity were also identified. In sediments from the Medee and Tyro basins, REE, Zr and Hf distributions were analysed in the fraction soluble in nitric acid, whereas in materials coming from the Thetis and Kryos basins, the water-soluble sediment fraction had been previously removed and REE, Zr and Hf distributions were investigated in the residue. This approach evidenced that shale-normalised REE patterns of the whole fraction soluble in nitric acid show strong intermediate REE (MREE) enrichments that give way to positive Gd anomalies once water-soluble minerals are removed. Y/Ho ratios are clustered around chondritic values justified by the occurrence of detritic minerals whereas Zr/Hf values span a~wider range from slightly subchondritic to superchondritic terms. Negative Gd anomalies, subchondritic Y/Ho and Zr/Hf values are found in Mg-carbonate rich samples suggesting that authigenic Mg-carbonates partition Ho and Hf with respect to Y and Zr during their crystallization from brines. Textural observations and biomass analyses highlighted effects of biological activities in sediments involving Zr and Hf enrichments and the highest Zr/Hf values according to the preferential Zr removal onto biological surfaces, without partitioning Y with respect to Ho. These first data suggest that Zr/Hf ratio and REE distributions can

  14. High precision Lu and Hf isotope analyses of both spiked and unspiked samples: A new approach

    NASA Astrophysics Data System (ADS)

    Lapen, Thomas J.; Mahlen, Nancy J.; Johnson, Clark M.; Beard, Brian L.

    2004-01-01

    The functional form of instrumentally produced mass fractionation associated with MC-ICP-MS analysis is not accurately known and therefore cannot be fully corrected by traditional approaches of internal normalization using power, linear, or exponential mass-bias laws. We present a method for robust correction of instrumentally produced mass-fractionation of both spiked and unspiked samples that can be applied to mass analysis of Hf as well as Nd, Sr, Os, etc. Correction of 176Hf/177Hf for unspiked samples follows a traditional approach of internal normalization using an exponential law, followed by normalization to a standard of known composition, such as JMC-475. For spiked samples, standards are used to characterize a linear instrumental mass-bias coefficient; the mass-bias coefficient is defined by the slope of a tie-line between measured and true values of a standard. This approximation results in identical precision and accuracy of measurements for spiked and unspiked samples (±0.005% 2σ, external reproducibility). The effects of the spike on the 176Hf/177Hf ratio and calculation of the molar spike-sample ratio is determined by a closed-form solution modified from the double-spike approach used for Fe isotope analysis by TIMS [Johnson and Beard, 1999]. The measured 176Lu/175Lu ratios are corrected by doping the sample with Er and using the 167Er/166Er ratio to externally normalize the 176Lu/175Lu ratio using an exponential law. Finally, spike-sample equilibration is confirmed for our sample dissolution protocol through analysis of varying physical mixtures of 1 Ga garnet and hornblende, where all the data lie on a mixing-line, within error, on a 176Lu/177Hf-176Hf/177Hf diagram. Precision of 176Lu/177Hf ratios is determined to be ±0.2% (2σ) for standards and for physical mixtures of garnet and hornblende.

  15. 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.

  16. DIRECT DETERMINATION OF THE HF/H{sub 2} ABUNDANCE RATIO IN INTERSTELLAR GAS

    SciTech Connect

    Indriolo, Nick; Neufeld, D. A.; Seifahrt, A.; Richter, M. J.

    2013-02-20

    We report the first detection of the v = 1-0, R(0) ro-vibrational transition of HF at 2.499385 {mu}m arising from interstellar gas. The line is seen in absorption toward three background sources-HD 154368, Elias 29, and AFGL 2136 IRS 1-all of which have reported H{sub 2} column densities determined from observations of H{sub 2}. This allows for the first direct determination of the HF/H{sub 2} abundance ratio. We find values of N(HF)/N(H{sub 2}) = 1.15 Multiplication-Sign 10{sup -8} and 0.69 Multiplication-Sign 10{sup -8} for HD 154368 and Elias 29, respectively. The sight line toward AFGL 2136 IRS 1 also shows absorption from the v = 1-0, R(1) transition of HF, indicating warm, dense (n {sub H} {approx}> 10{sup 9} cm{sup -3}) gas, likely very close to the central protostar. Ascribing portions of the HF absorption to warm and cold gas, we find N(HF)/N(H{sub 2}) = (1.7-2.9) Multiplication-Sign 10{sup -8} and (0.33-0.58) Multiplication-Sign 10{sup -8} for the two components, respectively. Except for the warm component toward AFGL 2136 IRS 1, all observed HF/H{sub 2} ratios are well below N(HF)/N(H{sub 2}) = 3.6 Multiplication-Sign 10{sup -8}, the value predicted if nearly all gas phase fluorine is in the form of HF. Models of fluorine chemistry that account for depletion onto grains are able to reproduce the results toward HD 154368, but not in the cold, dense gas toward AFGL 2136 IRS 1 and Elias 29. Most likely, some combinations of simplifying assumptions made in the chemical models are responsible for these discrepancies.

  17. 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.

  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. 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

  1. High local disorder in Tb2Hf2O7 pyrochlore oxide nanocrystals

    NASA Astrophysics Data System (ADS)

    Kabanova, V. A.; Popov, V. V.; Zubavichus, Ya V.; Kulik, E. S.; Yaroslavtsev, A. A.; Chernikov, R. V.; Menushenkov, A. P.

    2016-05-01

    The process of Tb2Hf2O7 nanocrystals formation upon annealing to 1600°C was investigated by means of X-ray absorption fine structure (XAFS) spectroscopy combined with X-ray diffraction (XRD) and pair distribution function (PDF) analysis. The structure ordering and the growth of nanocrystals upon annealing were estimated independently from XRD patterns and PDF. The probable content of Tb4+ ions in Tb2Hf2O7 was estimated from XANES. All studies indicate a high disorder and a large number of local structure defects in Tb2Hf2O7 pyrochlore oxide.

  2. 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.

  3. 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)

  4. Initial characterization of partially stabilized HfO/sub 2/ single crystals

    SciTech Connect

    Ingel, R.P.; Lewis, D.; Bender, B.A.; Rice, R.W.

    1982-09-01

    Results are presented for initial characterization of physical properties, microstructure, and phase structure of partially stabilized HfO/sub 2/ single crystals. These results, for crystals prepared by skull melting, are compared with those for ZrO/sub 2/ single crystals of similar composition and for fully stabilized ZrO/sub 2/ and HfO/sub 2/ single crystals. The observed microstructures and mechanical properties suggest that partially stabilized HfO/sub 2/ crystals may be useful high temperature structural ceramics.

  5. 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

  6. Dielectric and complex impedance properties of tetravalent hafnium (HF 4+) integrated cobalt ferrite

    NASA Astrophysics Data System (ADS)

    Sanchez, Luis

    The work presented in this thesis was carried out to understand the effects of tetravalent hafnium (Hf4+) ion on the crystal structure and phase, surface morphology, electrical, dielectric and complex impedance properties of cobalt ferrite (CoFe2O4; CFO). Hafnium incorporated cobalt ferrite, CoFe2-xHfxO4, with x = 0.00, 0.05, 0.075, 0.10, 0.15 and 0.20 were prepared by the standard solid state ceramic synthesis method. X-ray diffraction (XRD) and scanning electron microscopy (SEM) characterizations were performed to determine the structural properties. Most important aspect of this study is to explore the dielectric and complex impedance properties as a function of variable temperature (T=300-1000 K) and frequency (f=20 Hz -1 MHz). Room temperature and the temperature dependence of dielectric constant, loss factor, complex impedance, and the ac resistivity measurements enabled us to understand the effect of temperature and frequency on the electrical and dielectric properties on CoFe2-xHfxO4 and, thus, to derive structure-property relation. X-ray diffraction (XRD) patterns for Hf-incorporated CFO confirm the formation of majority of CFO spinel [with space group Fd3m (227)] phase, in addition to the small amount of HfO2 monoclinic [space group, P1 21/c (14)] phase leading to formation of CFO-Hf composites. The lattice constant values derived from XRD for CFO-Hf were found to increase from 8.374 A (x = 0.000) to 8.391 A (x = 0.200). The lattice expansion is significant at the very first step of Hf-incorporation and then slows down with progressive Hf-incorporation. SEM imaging analysis indicates that Hf resides at the grain boundaries for CFO-Hf. The dielectric constant (epsilon') of CFO-Hf is T-independent at T<450 K, at which point increasing trend prevails. A grain bulk-boundary based two-layer model, where semiconducting-grains separated by insulating-grain boundaries, satisfactorily accounts for epsilon- T (>450 K) variation. Correspondingly, electrical

  7. Lu-Hf isotope systematics of fossil biogenic apatite and their effects on geochronology

    NASA Astrophysics Data System (ADS)

    Herwartz, Daniel; Münker, Carsten; Tütken, Thomas; Hoffmann, J. Elis; Wittke, Andreas; Barbier, Bruno

    2013-01-01

    Reliable methods for direct dating of biogenic apatite from pre-Pleistocene fossils are currently not available, and recent attempts using the Lu-Hf decay system yielded highly inaccurate ages for both bones and teeth. The geological processes accounting for this poor accuracy of Lu-Hf chronometry are not yet understood. Here we explore Lu-Hf systematics in fossil bones and teeth in detail, by applying five different sample digestion techniques that are tested on bones and composites of bone and sediment. Our current dataset implies that dissolution methods only slightly affect the resulting Lu-Hf ages, while clear differences between the individual digestion techniques became apparent for element concentrations. By analysing the insoluble leftovers from incomplete sample dissolution, four main reservoirs of Hf in fossil bones were identified: (1) a radiogenic end-member associated with apatite; (2) an unradiogenic end-member represented by the authigenic minerals or the embedding sediment; (3) a highly unradiogenic end-member that can be attributed to detrital zircon; and (4) a moderately soluble phase (probably a Zr(Hf)-phosphate) that yielded very low Lu/Hf but a highly radiogenic Hf isotope composition at the same time. This Zr(Hf)-phase must have been precipitated within the fossil bone sample at a late stage of burial history, thereby incorporating radiogenic 176Hf released from apatite surfaces over geological timescales. A second focus of our study is the effect of different sediment matrices and of crystal size on the preservation of pristine Lu-Hf isotope compositions in bioapatite. Because near-depositional Lu-Hf ages of phosphate fossils have previously been reported for the London Clay (England) and a calcareous marl from Tendaguru (Tanzania), we herein investigate specimens fossilised in carbonate matrices (calcareous marl from Oker, Germany; carbonate concretions from the Santana Formation, Brazil; carbonate from the Eifel, Germany) and argillaceous

  8. Acute sinusitis.

    PubMed

    Feldt, Brent; Dion, Gregory R; Weitzel, Erik K; McMains, Kevin C

    2013-10-01

    Sinusitis is a common patient complaint that carries with it a large economic burden. It is one of the most common reasons patients visit their primary care physician. Acute bacterial rhinosinusitis (ABRS) can be distinguished from other forms of rhinosinusitis based on symptom duration of <4 weeks in a patient with purulent rhinorrhea associated with facial pain or pressure. Native upper aerodigestive tract bacteria are the most common etiologic agents. Treatment of ABRS is targeted primarily at symptom improvement. Amoxicillin can be used based on the clinical scenario and patient comorbidities. Computed tomographic scans are reserved for complicated presentations or when there is concern for intracranial extension or other complications. A systematic approach to ABRS will allow for improved patient quality of life and a decreased overall economic burden of this common entity.

  9. Mixed cation phases in sputter deposited HfO{sub 2}-TiO{sub 2} nanolaminates

    SciTech Connect

    Cisneros-Morales, M. C.; Aita, C. R.

    2008-07-14

    Nanolaminate HfO{sub 2}-TiO{sub 2} films are grown by reactive sputter deposition on unheated fused SiO{sub 2}, sequentially annealed at 573 to 973 K, and studied by x-ray diffraction. A nanocrystalline structure of orthorhombic (o) HfTiO{sub 4} adjacent to an interface followed by monoclinic (m) Hf{sub 1-x}Ti{sub x}O{sub 2} is identified. m-Hf{sub 1-x}Ti{sub x}O{sub 2}, a metastable phase, is isomorphous with m-HfO{sub 2} and a high pressure phase, m-HfTiO{sub 4}. A Vegard's law analysis shows that the Ti atomic fraction in m-Hf{sub 1-x}Ti{sub x}O{sub 2} is much greater than Ti equilibrium solubility in m-HfO{sub 2}. A space group-subgroup argument proposes that m-Hf{sub 1-x}Ti{sub x}O{sub 2} arises from an o/m-HfTiO{sub 4} second order phase transition to accommodate the larger Hf atom.

  10. 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.

  11. 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.

  12. The Li···HF van der Waals minimum and the barrier to the deep HF-Li potential well

    NASA Astrophysics Data System (ADS)

    Fan, Qunchao; Feng, Hao; Sun, Weiguo; Xie, Yaoming; Wu, Chia-Hua; Allen, Wesley D.; Schaefer, Henry F., III

    2014-03-01

    Molecular beam experiments (lithium atom plus hydrogen fluoride) by both Becker and co-workers (C.H. Becker, P. Casavecchia, P.W. Tiedemann, J.J.Valentini, and Y.T. Lee, J. Chem. Phys. 73, 2833 (1980)) and Loesch and Stienkemeier (H.J. Loesch and F. Stienkemeier, J. Chem. Phys. 98, 9570 (1993)) deduced a van der Waals complex of type Li...HF. In this research, molecular electronic structure theory [aug-cc-pCVQZ CCSD(T)] has been used to predict a well depth of 0.86 kcal mol-1 relative to separated Li + HF. However, the barrier from this vdW well to the more strongly bound (∼6.2 kcal mol-1) HFLi complex lies 0.43 kcal mol-1 below separated Li + HF. Special Issue of Molecular Physics: Seventh Molecular Quantum Mechanics Conference, Lugano, Switzerland, 2-7 June 2013.

  13. Equatorial ionospheric disturbance observed through a transequatorial HF propagation experiment

    NASA Astrophysics Data System (ADS)

    Maruyama, T.; Kawamura, M.

    2006-07-01

    A transequatorial radio-wave propagation experiment at shortwave frequencies (HF-TEP) was done between Shepparton, Australia, and Oarai, Japan, using the radio broadcasting signals of Radio Australia. The receiving facility at Oarai was capable of direction finding based on the MUSIC (Multiple Signal Classification) algorithm. The results were plotted in azimuth-time diagrams (AT plots). During the daytime, the propagation path was close to the great circle connecting Shepparton and Oarai, thus forming a single line in the AT plots. After sunset, off-great-circle paths, or satellite traces in the AT plot, often appeared abruptly to the west and gradually returned to the great circle direction. However, there were very few signals across the great circle to the east. The off-great-circle propagation was very similar to that previously reported and was attributed to reflection by an ionospheric structure near the equator. From the rate of change in the direction, we estimated the drift velocity of the structure to range mostly from 100 to 300 m/s eastward. Multiple instances of off-great-circle propagation with a quasi-periodicity were often observed and their spatial distance in the east-west direction was within the range of large-scale traveling ionospheric disturbances (LS-TIDs). Off-great-circle propagation events were frequently observed in the equinox seasons. Because there were many morphological similarities, the events were attributed to the onset of equatorial plasma bubbles.

  14. 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.

  15. 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).

  16. Tactical HF field expedient antenna performance, volume 2

    NASA Astrophysics Data System (ADS)

    Turkes, Gurkan

    1990-03-01

    This thesis investigates the performance of various configurations of tactical high frequency (HF) field deployable antennas in the presence of lossy earth. Antennas investigated include horizontal dipoles, short sloping wires, inverted vees, and monopoles with buried and elevated radials. Numerical models of the antennas are exercised via the Numerical Electromagnetic Code (NEC) for radiation pattern performance. Antennas are analyzed for applicability to the following: (1) short-range near vertical incident skywave (NVIS), where high elevation radiation angles are required; (2) medium- and long-range low radiation angle use; and (3) vertically polarized low-angle radiation for ground wave communication. Good NVIS and ground wave performance occurs for horizontal dipoles. Sloping wires and sloping dipoles are similar to horizontal dipoles but exhibit a moderate amount of azimuth plane directivity. Vertical monopoles with at least 15 buried radials produce medium- and long-range skywave coverage and good ground wave performance. Four elevated radials for quarter-wavelength monopoles are shown to out-perform 15 buried radials and are much easier to erect. The larger and more difficult-to-erect inverted vee dipole slightly outperforms a monopole by virtue of modest azimuth plane directivity. The results of this study can be included in an antenna engineering handbook and can be used to interface with existing ionospheric propagation codes in order to obtain optimum communication effectiveness

  17. Tactical HF field expedient antenna performance, volume 1

    NASA Astrophysics Data System (ADS)

    Turkes, Gurkan

    1990-03-01

    This thesis investigates the performance of various configurations of tactical High Frequency (HF) field deployable antennas in the presence of lossy earth. Antennas investigated include horizontal dipoles, short sloping wires, inverted vees, and monopoles with buried and elevated radials. Numerical models of the antennas are exercised via the Numerical Electromagnetics Code (NEC) for radiation pattern performance. Antennas are analyzed for applicability to (1) short-range Near Vertical Incident Skywave (NVIS), where high elevation radiation angles are required; (2) medium-and long-range low radiation angle use; and (3) vertically polarized low-angle radiation for ground wave communication. Good NVIS and ground wave performance occurs for horizontal dipoles. Sloping wires and sloping dipoles are similar to horizontal dipoles but exhibit a moderate amount of azimuth plane directivity. Vertical monopoles with at least 15 buried radials produce medium-and long-range skywave coverage and good ground wave performance. Four elevated radials for quarter-wavelength monopoles are shown to out-perform 15 buried radials and are much easier to erect. The larger and more difficult-to-erect inverted vee dipole slightly outperforms a monopole by virtue of modest azimuth plane directivity. The results of this study can be included in an antenna engineering handbook and can be used to interface with existing ionospheric propagation codes in order to obtain optimum communication effectiveness.

  18. 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.

  19. 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.

  20. 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.

  1. Long haul communications in the HF spectrum utilizing high speed modems

    NASA Astrophysics Data System (ADS)

    Ellis, Robert H.

    1988-03-01

    In the past ten years reliable high-speed satellite systems have pushed slower less reliable communication systems to the bottom of the list for development programs. Concern over reduced budgets, vulnerability of expensive satellite systems, and recent advances in HF technology are creating new interest in upgrading existing HF communication systems. Nondevelopment Items (NDI) are defined as the use of off-the-shelf commercial items instead of costly, time-consuming conventional research and development programs. The Navy Department's current policies are designed to insure the maximum use of NDI to fulfill Navy requirements. The speed of HF systems can be improved using current signaling and modulation techniques, and reliability can be increased by error-correcting codes or error detection used in conjunction with automatic repeat request (ARQ) schemes. Improved HF systems not only provide survivable back-up capability, but increased capacity for present communication needs.

  2. Reconciling Hf-W Model Ages of IVB Parent Body with Numerical Models

    NASA Astrophysics Data System (ADS)

    Neumann, W.; Breuer, D.; Kleine, T.; Kruijer, T.

    2016-08-01

    We calculated the differentiation of the parent body of IVB iron meteorites comparing its evolution to the metal separation data. Our models are consistent with the separation ages inferred from the Hf-W chronology.

  3. 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.

  4. 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.

  5. Crystal growth of HfS 2 by chemical vapour transport with halogen (Cl, Br, I)

    NASA Astrophysics Data System (ADS)

    Fiechter, S.; Eckert, K.

    1988-05-01

    Single crystals of HfS 2 have been prepared by chemical vapour transport (CVT) with halogen. Depending on the transporting agent added, exergonic or endergonic transport was observed. Employing 0.5 mg/cm 3 chlorine or bromine in evacuated and sealed quartz ampoules, exergonic transport occurs. In a temperature gradient from 850 to 870 K transparent reddish-orange crystal platelets of pseudohexagonal shape (10×10×0.05 mm3) were obtained. Endergonic transport, found with iodine as transporting agent, first starts at higher temperatures (1270-1220 K). A thermochemical study of the vapour phase composition revealed that gaseous HfHal 4 and HfHal 3 ( Hal = Cl, Br) are responsible for the exergonic transport observed. Because of the higher stability of HfS 2 against iodine, CVT first starts at elevated temperatures. In the vapour phase Hfl and Hfl 2 dominate and effect a reversal of the transport direction.

  6. 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.

  7. Strongly reduced Si surface recombination by charge injection during etching in diluted HF/HNO3.

    PubMed

    Greil, Stefanie M; Schöpke, Andreas; Rappich, Jörg

    2012-08-27

    Herein, we investigate the behaviour of the surface recombination of light-induced charge carriers during the etching of Si in alkaline (KOH) and acidic etching solutions of HF/HNO(3)/CH(3)COOH (HNA) or HF/HNO(3)/H(3)PO(4) (HNP) at different concentration ratios of HF and HNO(3) by means of photoluminescence (PL) measurements. The surface recombination velocity is strongly reduced during the first stages of etching in HF/HNO(3)-containing solutions pointing to a interface well passivated by the etching process, where a positive surface charge is induced by hole injection from NO-related surface species into the Si near-surface region (back surface field effect). This injected charge leads to a change in band bending by about 150 mV that repulses the light-induced charge carriers from the surface and therefore enhances the photoluminescence intensity, since non-radiative surface recombination is reduced.

  8. Recent Terrestrial Disturbance of the 176Lu-176Hf Systematics in Meteorites

    NASA Astrophysics Data System (ADS)

    Bast, R.; Scherer, E. E.; Sprung, P.; Mezger, K.; Bischoff, A.

    2016-08-01

    The Lu-Hf isotope systematics of many achondrites exhibit excessive scatter above a solar system isochron that cannot be explained by early solar system processes but by recent terrestrial weathering or contamination.

  9. Optical detection of concentrations for mixed acid: HF and HNO3

    NASA Astrophysics Data System (ADS)

    Kang, Gumin; Kim, Kyoungsik

    2009-02-01

    Mixed acid, which consist of HF and HNO3, is used as a good etchant for silicon dioxide in the wet etching and pickling process of stainless steel. The optical detection of concentration for such mixed acids is crucial to optimize and cut costs in the manufacturing process. Optical detection in the IR regime has been utilized to measure the concentration of the mixed acid for HF and HNO3, because that has several strong absorption peaks, which is contributed by vibrational mode of each acid molecular in this spectrum. In this research, we observed the concentrations of mixed acid to consist of HF and HNO3, as we measured the absorption intensity of OH- stretch and NO3 - stretch band by optical spectroscopy. The concentration range of HF over 1.5-3 wt% and that of HNO3 over 2-10 wt% were studied in room temperature.

  10. 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

  11. Deformation and its influence on K isomerism in neutron-rich Hf nuclei

    SciTech Connect

    Liu, H. L.; Bertulani, C. A.; Xu, F. R.; Walker, P. M.

    2011-06-15

    We investigate the influence of deformation on the possible occurrence of long-lived K isomers in Hf isotopes around N=116, using configuration-constrained calculations of potential-energy surfaces. Despite having reduced shape elongation, the multiquasiparticle states in {sup 186,188}Hf remain moderately robust against triaxial distortion, supporting the long expected occurrence of exceptionally long-lived isomers. The calculations are compared with available experimental data.

  12. 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

  13. CE8N -- A new generation of HF modified stainless steel for refinery service

    SciTech Connect

    Gapinski, G.E.

    1995-11-01

    A new generation of HF Modified stainless steel has been developed for hydrocracker/hydrotreater transfer line piping system applications. The new alloy, CE8N, contains lower carbon and higher nitrogen than previous versions of HF Modified. This new alloy offers improved aged toughness, increased resistance to sensitization, and enhanced polythionic acid-stress corrosion cracking resistance. Strength levels of the new alloy are somewhat below CE20N at temperatures up to 850 F (454 C).

  14. 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.

  15. 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.

  16. Ultrathin Hf0.5Zr0.5O2 Ferroelectric Films on Si.

    PubMed

    Chernikova, Anna; Kozodaev, Maksim; Markeev, Andrei; Negrov, Dmitrii; Spiridonov, Maksim; Zarubin, Sergei; Bak, Ohheum; Buragohain, Pratyush; Lu, Haidong; Suvorova, Elena; Gruverman, Alexei; Zenkevich, Andrei

    2016-03-23

    Because of their immense scalability and manufacturability potential, the HfO2-based ferroelectric films attract significant attention as strong candidates for application in ferroelectric memories and related electronic devices. Here, we report the ferroelectric behavior of ultrathin Hf0.5Zr0.5O2 films, with the thickness of just 2.5 nm, which makes them suitable for use in ferroelectric tunnel junctions, thereby further expanding the area of their practical application. Transmission electron microscopy and electron diffraction analysis of the films grown on highly doped Si substrates confirms formation of the fully crystalline non-centrosymmetric orthorhombic phase responsible for ferroelectricity in Hf0.5Zr0.5O2. Piezoresponse force microscopy and pulsed switching testing performed on the deposited top TiN electrodes provide further evidence of the ferroelectric behavior of the Hf0.5Zr0.5O2 films. The electronic band lineup at the top TiN/Hf0.5Zr0.5O2 interface and band bending at the adjacent n(+)-Si bottom layer attributed to the polarization charges in Hf0.5Zr0.5O2 have been determined using in situ X-ray photoelectron spectroscopy analysis. The obtained results represent a significant step toward the experimental implementation of Si-based ferroelectric tunnel junctions.

  17. The molecular frame electric dipole moment and hyperfine interactions in hafnium fluoride, HfF.

    PubMed

    Le, Anh; Steimle, Timothy C; Skripnikov, Leonid; Titov, Anatoly V

    2013-03-28

    The (1,0) [17.9]2.5-X(2)Δ(3∕2) band of hafnium monofluoride (HfF) has been recorded using high-resolution laser-induced fluorescence spectroscopy both field-free and in the presence of a static electric field. The field-free spectra of (177)HfF, (179)HfF, and (180)HfF were modeled to generate a set of fine and hyperfine parameter for the X(2)Δ(3∕2)(v = 0) and [17.9]2.5 (v = 1) states. The observed optical Stark shifts for the (180)HfF isotopologue were analyzed to produce the molecular frame electric dipole moments of 1.66(1) D and 0.419(7) D for the X(2)Δ(3∕2) and [17.9]2.5 state, respectively. Both the generalized effective core potential and all-electron four component approaches were used in ab initio calculations to predict the properties of ground state HfF including equilibrium distance, dipole moments, quadrupole coupling, and magnetic hyperfine constants.

  18. Quadrupole moment measurements for strongly deformed bands in {sup 171,172}Hf

    SciTech Connect

    Mukhopadhyay, S.; Ma, W. C.; Ijaz, Q. A.; Marsh, J.; Yadav, R. B.; Janssens, R. V. F.; Carpenter, M. P.; Khoo, T. L.; Lauritsen, T.; Zhu, S.; Chiara, C. J.; Chowdhury, P.; Hota, S. S.; Lakshmi, S.; Cullen, D. M.; Hagemann, G. B.; Hartley, D. J.; Kondev, F. G.; Riedinger, L. L.; Toh, Y.

    2011-04-15

    A lifetime experiment, using the Doppler-shift attenuation method, has been performed at Gammasphere to measure the transition quadrupole moments Q{sub t} of strongly deformed bands in {sup 171}Hf and {sup 172}Hf. The measured value of Q{sub t} {approx} 9.5 e b for the band labeled ED in {sup 171}Hf strongly supports the recent suggestion that this sequence and several structures with similar properties in neighboring Hf isotopes are associated with a near-prolate shape with a deformation enhanced relative to that of normal deformed structures. The measured values of Q{sub t} {approx} 14 e b for the bands labeled SD1 and SD3 in {sup 172}Hf confirm that these sequences are associated with a prolate superdeformed shape, a property inferred in earlier work from other measured characteristics of the bands. Similar bands in {sup 173-175}Hf are also likely to be associated with superdeformed shapes. The observations are in contrast to predictions of cranking calculations performed with the ultimate cranker code.

  19. Epidermal lipids and the natural history of hydrofluoric acid (HF) injury.

    PubMed

    Noonan, T; Carter, E J; Edelman, P A; Zawacki, B E

    1994-06-01

    To explain several fortuitous observations, we hypothesized that there is a naturally occurring lipid 'barrier' to HF injury in guinea-pig skin and sought to characterize both the barrier and its role in the natural history of such injuries. Under anaesthesia, the dorsal trunk skin of groups of guinea-pigs was gently clipped of hair, washed with chloroform, soap and water, acetone or nothing (controls), and examined histologically for the presence of neutral lipid. Thereafter, in animal groups similarly washed, 1.5 in x 1.5 in (38 mm x 38 mm) areas were exposed to 40 per cent HF for up to 50 min and: (a) mean percentages of exposed areas with gross necrosis 5 days postinjury plotted on dose-response curves; or (b) less than 4 h after exposure to HF, intra-aortic India ink was injected and skin specimens examined to discern depth of ischaemia and necrosis. In contrast to controls, washing reduced neutral lipid in epidermis and significantly (at P < 0.001) increased susceptibility to injury by HF. With very rare (but interesting) exceptions, HF injury was found to be full thickness in depth with ischaemia and coagulative necrosis. In this study, development of guinea-pig skin necrosis due to HF was typically an 'all-or-nothing' 'barrier-penetration' phenomenon relating as much to the integrity of an epidermal lipid barrier as to the duration and intensity of noxious exposure.

  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.

  1. 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.

  2. HfO{sub x}N{sub y} gate dielectric on p-GaAs

    SciTech Connect

    Dalapati, G. K.; Sridhara, A.; Wong, A. S. W.; Chia, C. K.; Chi, D. Z.

    2009-02-16

    Plasma nitridation method is used for nitrogen incorporation in HfO{sub 2} based gate dielectrics for future GaAs-based devices. The nitrided HfO{sub 2} (HfO{sub x}N{sub y}) films on p-GaAs improve metal-oxide-semiconductor device characteristics such as interface state density, accumulation capacitance, hysteresis, and leakage current. An equivalent oxide thickness of 3.6 nm and a leakage current density of 10{sup -6} A cm{sup -2} have been achieved at V{sub FB}-1 V for nitrided HfO{sub 2} films. A nitride interfacial layer (GaAsO:N) was observed at HfO{sub 2}-GaAs interface, which can reduce the outdiffusion of elemental Ga and As during post-thermal annealing process. Such suppression of outdiffusion led to a substantial enhancement in the overall dielectric properties of the HfO{sub 2} film.

  3. Electronic structure characterization of La incorporated Hf-based high-k gate dielectrics by NEXAFS.

    PubMed

    Yamamoto, Takashi; Ogawa, Singo; Kunisu, Masahiro; Tsuji, Junichi; Kita, Koji; Saeki, Masayuki; Oku, Yudai; Arimura, Hiroaki; Kitano, Naomu; Hosoi, Takuji; Shimura, Takayoshi; Watanabe, Heiji

    2011-04-01

    The electronic structures of lanthunum (La) incorporated hafnium (Hf)-based oxides (HfLaO) and their silicate (HfLaSiO) films were investigated by the Near Edge X-ray Absorption Fine Structure (NEXAFS) technique. The oxygen (O) K-edge spectra, which reflected the hybridized Hf 5d state with the O 2p orbital, were found to reveal features of the unoccupied state of the metal oxides, as well as the conduction-band edge. We also found that, while La incorporation into the Hf-based oxides simply changed the features of the conduction-band structure, subsequent thermal annealing of the La-incorporated films led to a conduction-band edge shift due to an interface silicate reaction and/or local bond rearrangement depending on the La concentration and annealing temperature. The impact of La incorporation into the Hf-based high-k materials on the electronic structure is discussed by taking into account the intrinsic nature of these metal oxides.

  4. 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.

  5. 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.

  6. HfCo7-Based Rare-Earth-Free Permanent-Magnet Alloys

    SciTech Connect

    Das, B; Balamurugan, B; Kumar, P; Skomski, R; Shah, VR; Shield, JE; Kashyap, A; Sellmyer, DJ

    2013-07-01

    This study presents the structural and magnetic properties of melt-spun HfCo7, HfCo7-xFex (0.25 <= x <=), and HfCo7Six (0.2 <= x <= 1.2) alloys. Appreciable permanent-magnet properties with a magnetocrystalline anisotropy of about 9.6-16.5, Mergs/cm(3), a magnetic polarization J(s) approximate to 7.2-10.6 kG, and coercivities H-c = 0.5-3.0 kOe were obtained by varying the composition of these alloys. Structural analysis reveals that the positions of x-ray diffraction peaks of HfCo7 show good agreement with those corresponding to an orthorhombic structure having lattice parameters of about a = 4.719 angstrom, b = 4.278 angstrom, and c = 8.070 angstrom. Based on these results, a model crystal structure for HfCo7 is developed and used to estimate the magnetic properties of HfCo7 using density-functional calculations, which agree with the experimental results.

  7. Microstructure of laser clad Ni- Cr- Al- Hf alloy on a γ' strengthened ni- base superalloy

    NASA Astrophysics Data System (ADS)

    Singh, Jogender; Mazumder, J.

    1988-08-01

    Alloys and coatings for alloys for improved high temperature service life under aggressive atmo-spheres are of great contemporary interest. There is a general consensus that the addition of rare earths such as Hf will provide many beneficial effects for such alloys. The laser cladding technique was used to produce Ni-Cr-AI-Hf alloys with extended solid solution of Hf. A 10 kW CO2 laser with mixed powder feed was used for laser cladding. Optical, scanning electron (SEM) and scanning transmission electron (STEM) microscopy were employed to characterize the microstructure of alloys produced during laser cladding processes. Microstructural studies revealed grain refinement, considerable in-crease in solubility of Hf in the matrix, Hf-rich precipitates, and new metastable phases. The size and morphology of γ' (Ni3Al) phase were discussed in relation to its microchemistry and the laser processing conditions. This paper will report the microstructural development in this laser clad Ni-Cr-AI-Hf alloy.

  8. Microstructure dependent filament forming kinetics in HfO2 programmable metallization cells.

    PubMed

    Clarke, Heidi; Brown, Timothy; Hu, Jianjun; Ganguli, Raj; Reed, Amber; Voevodin, Andrey; Shamberger, Patrick J

    2016-10-21

    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. PMID:27632249

  9. The effect of silicon on the oxidation behavior of NiAlHf coating system

    NASA Astrophysics Data System (ADS)

    Dai, Pengchao; Wu, Qiong; Ma, Yue; Li, Shusuo; Gong, Shengkai

    2013-04-01

    Two types of NiAlHf coatings doped with different content of Si (1 at.% and 2 at.%) were deposited on a Ni3Al based single crystal superalloy IC32 by electron beam physical vapor deposition (EB-PVD) method, respectively. For comparison, NiAlHf coating with 0 at.% Si was also prepared. The oxidation tests were carried out at 1423 K in air. At the initial stage of oxidation, large amount of flake-like θ-Al2O3 was found on NiAlHf coating surface. However, no θ-Al2O3 was observed in 2 at.% Si doped NiAlHf coating except α-Al2O3. It revealed that the Si additions could contribute to the transformation from θ-Al2O3 to α-Al2O3. When oxidation time prolonged to 100 h, it was found that the degradation of NiAlHf coating was very severe with no residual β-phase, which was due to the serious inter-diffusion between the coating and substrate. In contrast, the inter-diffusion in Si-doped coating was reduced with some residual β-phase and R-Ni(Mo, Re) precipitates. The presence of Si could retard the inter-diffusion of elements between coating and substrate, indicating a barrier diffusion effect. As a result, the oxidation resistance of NiAlHf coating was improved significantly.

  10. Clinical outcome of acute and chronic hepatitis delta over time: a long-term follow-up study.

    PubMed

    Buti, M; Homs, M; Rodriguez-Frias, F; Funalleras, G; Jardí, R; Sauleda, S; Tabernero, D; Schaper, M; Esteban, R

    2011-06-01

    Long-term changes in the frequency and outcome of hepatitis delta virus (HDV) infection have seldom been analysed. This retrospective, longitudinal study includes 398 consecutive hepatitis B surface antigen (HBsAg)-positive patients with anti-HDV antibodies who attended our institution between 1983 and 2008. At enrolment, 182 patients had acute and 216 chronic hepatitis. Patients were grouped into two periods. Those who attended between 1983 and 1995 and those between 1996 and 2008. The former group was significantly younger, mainly intravenous drugs users, and had a greater incidence of acute HDV and HIV and HCV coinfection. Patients with acute HBV/HDV coinfection cleared both infections in 90% of cases, while all patients with HDV superinfection evolved to chronic disease. One hundred and fifty-eight patients with chronic HDV were followed for a median period of 158months. Seventy-two per cent of the patients remained stable, 18% had hepatic decompensation, 3% developed hepatocellular carcinoma, and 8% cleared HBsAg. Liver-related death was observed in 13% of patients and mainly occurred in patients from the first period (P=0.012). These results indicate an outbreak of HDV at the end of the 1980s and the beginning of the 1990s, with a large number of acute HDV cases affecting predominately young, male intravenous drug users. Currently, patients with chronic HDV disease are older, and factors associated with worse prognosis include the presence of cirrhosis and age at the time of diagnosis.

  11. Finishing and Commissioning the New Arecibo HF Facility

    NASA Astrophysics Data System (ADS)

    Sulzer, M. P.; Gonzalez, S. A.

    2011-12-01

    The imminent completion of the major tasks in the construction of the New Arecibo HF facility means that we must verify that the components are working as intended. The antenna system and the transmitters must be separately commissioned before they can be connected together so that we an be sure it will provide 83 dbW at 8.175 MHz, and 80 dbW at 5.1 MHz. The antenna system will be ready for initial testing in September. It Illuminates the 305 meter dish using dipoles near the surface of the dish transmitting upward to a wire mesh sub-reflector. There are three crossed dipoles for each of the two frequencies. The dipoles are supported on towers mounted on concrete pads underneath the dish. Each dipole element is connected to a transmitter through a three inch coax line. The tower foundations are nearly complete, and the towers will be erected in early September, and we expect to have at least one crossed dipole in place for initial testing by the end of September. We will need to make some measurements on the antenna system to ensure that it meets our requirements. One requirement is to match the antenna impedance to the transmission line and the transmitter closely enough to meet the transmitter specifications, the closer, the better. We have additional requirements; for example, it is necessary for efficient use of the facility that the polarization be close to circular. In most experiments, we want O mode excitation. If we were to transmit linear only half the power would reach the reflection height. The symmetry of the system assures that most of the conditions for achieving accurate circular polarization are met, but one condition is not: that exciting the transmitters driving the orthogonal elements at 90 degrees assures 90 degree separation in the corresponding antenna currents. One of the dipoles of each pair points toward the center of the array. If we think of the three crossed dipoles as consisting of a reference and two that are excited relative to it

  12. Dynamic NBTI effects in HfSiON.

    SciTech Connect

    Devine, Roderick A. B.; Kambour, Kenneth E.; Hjalmarson, Harold Paul; Mee, Jesse K.

    2010-12-01

    Negative bias temperature instability is an issue of critical importance as the space electronics industry evolves because it may dominate the reliability lifetime. Understanding its physical origin is therefore essential in determining how best to search for methods of mitigation. It has been suggested that the magnitude of the effect is strongly dependent on circuit operation conditions (static or dynamic modes). In the present work, we examine the time constants related to the charging and recovery of trapped charged induced by NBTI in HfSiON gate dielectric devices. In previous work, we avoided the issue of charge relaxation during acquisition of the I{sub ds}(V{sub gs}) curve by invoking a continuous stressing technique whereby {Delta}V{sub th} was extracted from a series of single point I{sub ds} measurements. This method relied heavily on determination of the initial value of the source-drain current (I{sub ds}{sup o}) prior to application of gate-source stress. In the present work we have used a new pulsed measurement system (Keithley SCS 4200-PIV) which not only removes this uncertainty but also permits dynamic measurements in which devices are AC stressed (Fig. 1a) or subjected to cycles of continued DC stresses followed by relaxation (Fig. 1b). We can now examine the charging and recovery characteristics of NBTI with higher precision than previously possible. We have performed NBTI stress experiments at room temperature on p-channel MOSFETs made with HfSiON gate dielectrics. In all cases the devices were stressed in the linear regime with V{sub ds}=-0.1V. We have defined two separate waveforms/pulse trains as illustrated in Fig 1. These were applied to the gate of the MOSFET. Firstly we examined the charging characteristics by applying an AC stress at 2.5MHz or 10Hz for different times. For a 50% duty cycle this corresponded to V{sub gs} = - 2V pulses for 200ns or 500ms followed by V{sub gs} = 0V pulses for 200ns or 500ms recovery respectively. In

  13. Chronic Liver Failure-Sequential Organ Failure Assessment is better than the Asia-Pacific Association for the Study of Liver criteria for defining acute-on-chronic liver failure and predicting outcome

    PubMed Central

    Dhiman, Radha K; Agrawal, Swastik; Gupta, Tarana; Duseja, Ajay; Chawla, Yogesh

    2014-01-01

    AIM: To compare the utility of the Chronic Liver Failure-Sequential Organ Failure Assessment (CLIF-SOFA) and Asia-Pacific Association for the Study of Liver (APASL) definitions of acute-on-chronic liver failure (ACLF) in predicting short-term prognosis of patients with ACLF. METHODS: Consecutive patients of cirrhosis with acute decompensation were prospectively included. They were grouped into ACLF and no ACLF groups as per CLIF-SOFA and APASL criteria. Patients were followed up for 3 mo from inclusion or mortality whichever was earlier. Mortality at 28-d and 90-d was compared between no ACLF and ACLF groups as per both criteria. Mortality was also compared between different grades of ACLF as per CLIF-SOFA criteria. Prognostic scores like CLIF-SOFA, Acute Physiology and Chronic Health Evaluation (APACHE)-II, Child-Pugh and Model for End-Stage Liver Disease (MELD) scores were evaluated for their ability to predict 28-d mortality using area under receiver operating curves (AUROC). RESULTS: Of 50 patients, 38 had ACLF as per CLIF-SOFA and 19 as per APASL criteria. Males (86%) were predominant, alcoholic liver disease (68%) was the most common etiology of cirrhosis, sepsis (66%) was the most common cause of acute decompensation while infection (66%) was the most common precipitant of acute decompensation. The 28-d mortality in no ACLF and ACLF groups was 8.3% and 47.4% (P = 0.018) as per CLIF-SOFA and 39% and 37% (P = 0.895) as per APASL criteria. The 28-d mortality in patients with no ACLF (n = 12), ACLF grade 1 (n = 11), ACLF grade 2 (n = 14) and ACLF grade 3 (n = 13) as per CLIF-SOFA criteria was 8.3%, 18.2%, 42.9% and 76.9% (χ2 for trend, P = 0.002) and 90-d mortality was 16.7%, 27.3%, 78.6% and 100% (χ2 for trend, P < 0.0001) respectively. Patients with prior decompensation had similar 28-d and 90-d mortality (39.3% and 53.6%) as patients without prior decompensation (36.4% and 63.6%) (P = NS). AUROCs for 28-d mortality were 0.795, 0.787, 0.739 and 0.710 for

  14. HfO{sub 2} dielectric thickness dependence of electrical properties in graphene field effect transistors with double conductance minima

    SciTech Connect

    Zhang, Cheng; Xie, Dan Xu, Jian-Long; Sun, Yi-Lin; Dai, Rui-Xuan; Li, Xian; Li, Xin-Ming; Zhu, Hong-Wei

    2015-10-14

    We investigate the electrical properties in back-gated graphene field effect transistors (GFETs) with SiO{sub 2} dielectric and different thickness of high-k HfO{sub 2} dielectric. The results show that transform characteristic (I{sub ds}–V{sub gs}) curves of GFETs are uniquely W-shaped with two charge neutrality point (left and right) in both SiO{sub 2} and HfO{sub 2} dielectric (SiO{sub 2}-GFETs and HfO{sub 2}-GFETs). The gate voltage reduces drastically in HfO{sub 2}-GFETs compared with that in SiO{sub 2}-GFETs, and it becomes much smaller with the decline of HfO{sub 2} thickness. The left charge neutrality point in I{sub d}–V{sub g} curves of all HfO{sub 2}-GFETs is negative, compared to the positive ones in SiO{sub 2}-GFETs, which means that there exists n-doping in graphene with HfO{sub 2} as bottom dielectric. We speculate that this n-doping comes from the HfO{sub 2} layer, which brings fixed charged impurities in close proximity to graphene. The carrier mobility is also researched, demonstrating a decreasing trend of hole mobility in HfO{sub 2}-GFETs contrast to that in SiO{sub 2}-GFETs. In a series of HfO{sub 2}-GFETs with different HfO{sub 2} dielectric thickness, the hole mobility shows a tendency of rise when the thickness decreases to 7 nm. The possible reason might be due to the introduced impurities into HfO{sub 2} film from atomic layer deposition process, the concentration of which varies from the thickness of HfO{sub 2} layer.

  15. HfO2 dielectric thickness dependence of electrical properties in graphene field effect transistors with double conductance minima

    NASA Astrophysics Data System (ADS)

    Zhang, Cheng; Xie, Dan; Xu, Jian-Long; Li, Xin-Ming; Sun, Yi-Lin; Dai, Rui-Xuan; Li, Xian; Zhu, Hong-Wei

    2015-10-01

    We investigate the electrical properties in back-gated graphene field effect transistors (GFETs) with SiO2 dielectric and different thickness of high-k HfO2 dielectric. The results show that transform characteristic (Ids-Vgs) curves of GFETs are uniquely W-shaped with two charge neutrality point (left and right) in both SiO2 and HfO2 dielectric (SiO2-GFETs and HfO2-GFETs). The gate voltage reduces drastically in HfO2-GFETs compared with that in SiO2-GFETs, and it becomes much smaller with the decline of HfO2 thickness. The left charge neutrality point in Id-Vg curves of all HfO2-GFETs is negative, compared to the positive ones in SiO2-GFETs, which means that there exists n-doping in graphene with HfO2 as bottom dielectric. We speculate that this n-doping comes from the HfO2 layer, which brings fixed charged impurities in close proximity to graphene. The carrier mobility is also researched, demonstrating a decreasing trend of hole mobility in HfO2-GFETs contrast to that in SiO2-GFETs. In a series of HfO2-GFETs with different HfO2 dielectric thickness, the hole mobility shows a tendency of rise when the thickness decreases to 7 nm. The possible reason might be due to the introduced impurities into HfO2 film from atomic layer deposition process, the concentration of which varies from the thickness of HfO2 layer.

  16. The Molecular Frame Electric Dipole Moment and Hyperfine Interactions in Hafnium Fluoride, HfF

    NASA Astrophysics Data System (ADS)

    Le, Anh; Steimle, Timothy C.; Skripnikov, Leonid; Titov, Anatoly V.

    2013-06-01

    The identification of HfF^{+} as a possible candidate for a d_{e}} measurement has stimulated new interest in the spectroscopy of both HfF^{+} and neutral HfF. Studies of the neutral are relevant because photoionization schemes can be used to produce the cations. More importantly, computational methodologies used to predict the electronic wavefunction of HfF^{+} can be effectively assessed by making a comparison of predicted and experimental properties of the neutral, which are more readily determinable. The (1,0)[17.9]2.5 -X^{2}Δ_{3/2} band of hafnium monofluoride (HfF) has been recorded using high-resolution laser-induced fluorescence spectroscopy both field-free and in the presence of a static electric field. The field-free spectra of ^{177}HfF, ^{179}HfF, and ^{180}HfF were model to generate a set of fine and hyperfine parameters for the X^{2}Δ_{3/2} (v=0) and [17.9]2.5 (v=1) states. The observed optical Stark shifts for the ^{180}HfF isotopologue were analyzed to produce the molecular frame electric dipole moments of 1.66(1)D and 0.419(7)D for the X^{2}Δ_{3/2} and [17.9]2.5 states, respectively. A two-step ab initio calculation consisting of a two-component generalized relativistic effective core potential calculation (GRECP) followed by a restoration of the proper four-component wavefunction was performed to predict the properties of ground state HfF. B. J. Barker, I. O. Antonov, V. E. Bondybey, and M. C. Heaven, J. Chem. Phys., 134, 201102 (2011). K. C. Cossel, D. N. Gresh, L. C. Sinclair, T. Coffey, L. V. Skripnikov, A. N. Petrov, N. S. Mosyagin, A. V. Titov, R. W. Field, E. R. Meyer, E. A. Cornell and J. Ye, Chem. Phys. Lett., 546, 1 (2012). M. Grau, A. E. Leanhardt, H. Loh, L. C. Sinclair, R. P. Stutz, T. S. Yahn, and E. A. Cornell, J. Mol. Spectroc., 272, 32 (2012). H. Loh, R. P. Stutz, T. S. Yahn, H. Looser, R. W. Field, and E. A. Cornell, J. Mol. Spectroc.,276-277, 49 (2012).

  17. Hf Isotope Geochemistry of USGS Reference Materials and Various Labware: Insight into Potential Contaminant Sources

    NASA Astrophysics Data System (ADS)

    Weis, D.; Nobre Silva, I.; Kieffer, B.; Barling, J.; Pretorius, W.; Maerschalk, C.

    2005-12-01

    We have undertaken a high-precision geochemical and isotopic study of USGS reference materials by HR-ICP-MS, TIMS and MC-ICP-MS, including basalt (BCR-1,2; BHVO-1,2), andesite (AGV-1,2), rhyolite (RGM-1), syenite (STM-1,2), granodiorite (GSP-2), and granite (G-2,3). Only a few 176Hf/177Hf results are published on these materials and with the increased use of MC-ICP-MS it is critical to build a solid reference database. Standard hotplate dissolution was used, except for granitoid compositions where it involved a high-pressure bomb procedure. The reproducibility of 176Hf/177Hf is better than 100 ppm for granitoid compositions (G-2: 0.282523±8; G-3: 0.282505±20; GSP-2: 0.282059±27) and better than 65 ppm for basaltic/andesitic compositions in glassware and better than 30 ppm in teflon (BCR-2: 0.282872±9; BHVO-2: 0.283103±6). Overall, our results agree with the rare published data (BCR-1&2, BHVO-1 and RGM-1). Slight differences appear depending on the chemical procedure used to separate Hf and the type of labware used. There are systematic shifts in 176Hf/177Hf for basaltic compositions towards lower values (by 100-150 ppm) when non-teflon material is used. As a result, we then carried out a systematic trace element and isotopic study of various labware, including borosilicate glass and quartz columns and frits. Maximum concentrations (in ppm) of these materials (in the order listed above) are: Hf=16-0.3-22, Nd=0.8-0.1-23, Sr=8-0.08-16, Pb=1.4-0.5-14. The frit material appears the most variable in elemental concentration and isotopic composition, which might reflect various accumulations resulting from column chemistry. 176Hf/177Hf is 0.282198±4 in borosilicate glass and even lower in some of the frit material (<0.28195). Only a small amount of such unradiogenic material can account for the shifts observed in basaltic rocks. Our systematic study shows that careful analyses of rock reference materials with different compositional matrices are necessary, in

  18. Hard magnetic property enhancement of Co{sub 7}Hf-based ribbons by boron doping

    SciTech Connect

    Chang, H. W.; Liao, M. C.; Shih, C. W.; Chang, W. C.; Yang, C. C.; Hsiao, C. H.; Ouyang, H.

    2014-11-10

    Hard magnetic property enhancement of melt spun Co{sub 88}Hf{sub 12} ribbons by boron doping is demonstrated. B-doping could not only remarkably enhance the magnetic properties from energy product ((BH){sub max}) of 2.6 MGOe and intrinsic coercivity ({sub i}H{sub c}) of 1.5 kOe for B-free Co{sub 88}Hf{sub 12} ribbons to (BH){sub max} = 7.7 MGOe and {sub i}H{sub c} = 3.1 kOe for Co{sub 85}Hf{sub 12}B{sub 3} ribbons but also improve the Curie temperature (T{sub C}) of 7:1 phase. The (BH){sub max} value achieved in Co{sub 85}Hf{sub 12}B{sub 3} ribbons is the highest in Co-Hf alloy ribbons ever reported, which is about 15% higher than that of Co{sub 11}Hf{sub 2}B ribbons spun at 16 m/s [M. A. McGuire, O. Rios, N. J. Ghimire, and M. Koehler, Appl. Phys. Lett. 101, 202401 (2012)]. The structural analysis confirms that B enters the orthorhombic Co{sub 7}Hf (7:1) crystal structure as interstitial atoms, forming Co{sub 7}HfB{sub x}, in the as-spun state. Yet B may diffuse out from the 7:1 phase after post-annealing, leading to the reduction of Curie temperature and the magnetic properties. The uniformly refined microstructure with B-doping results in high remanence (B{sub r}) and improves the squareness of demagnetization curve. The formation of interstitial-atom-modified Co{sub 7}HfB{sub x} phase and the microstructure refinement are the main reasons to give rise to the enhancement of hard magnetic properties in the B-containing Co{sub 7}Hf-based ribbons.

  19. A study of the structure of the ν1(HF) absorption band of the СH3СN…HF complex

    NASA Astrophysics Data System (ADS)

    Gromova, E. I.; Glazachev, E. V.; Bulychev, V. P.; Koshevarnikov, A. M.; Tokhadze, K. G.

    2015-09-01

    The ν1(HF) absorption band shape of the CH3CN…HF complex is studied in the gas phase at a temperature of 293 K. The spectra of gas mixtures CH3CN/HF are recorded in the region of 4000-3400 cm-1 at a resolution from 0.1 to 0.005 cm-1 with a Bruker IFS-120 HR vacuum Fourier spectrometer in a cell 10 cm in length with wedge-shaped sapphire windows. The procedure used to separate the residual water absorption allows more than ten fine-structure bands to be recorded on the low-frequency wing of the ν1(HF) band. It is shown that the fine structure of the band is formed primarily due to hot transitions from excited states of the low-frequency ν7 librational vibration. Geometrical parameters of the equilibrium nuclear configuration, the binding energy, and the dipole moment of the complex are determined from a sufficiently accurate quantum-chemical calculation. The frequencies and intensities for a number of spectral transitions of this complex are obtained in the harmonic approximation and from variational solutions of anharmonic vibrational problems.

  20. Laser-clad Ni70Al20Cr7Hf3 alloys with extended solid solution of Hf: Part I. Microstructure evolution

    NASA Astrophysics Data System (ADS)

    Sircar, S.; Ribaudo, C.; Mazumder, J.

    1989-11-01

    Coatings for superalloys for extended service in atmospheres at high temperature are of great interest at present. The addition of reactive elements (RE’s) such as Hf to these coatings has a pronounced effect on their high-temperature oxidation resistance. A laser-cladding technique was used to produce Ni-Al-Cr-Hf alloys with an extended solid solution of Hf in a nearstoichiometric Ni3Al matrix. A 10 kW CO2 laser with mixed powder feed was used for the cladding process. Scanning electron microscope (SEM), transmission electron microscope (TEM), and scanning transmission electron microscope (STEM) were employed for studies of microstructural evolution of alloys produced during the laser-cladding process. Microstructural studies reveal the formation of dendrites with a solid solubility of about 11 to 14 wt pct Hf and also a eutectic structure. Convergent-beam techniques and X-ray spectroscopy have been applied to characterize the phases formed during the cladding process.

  1. REE and Hf distribution among mineral phases in the CV-CK clan: A way to explain present-day Hf isotopic variations in chondrites

    NASA Astrophysics Data System (ADS)

    Martin, Céline; Debaille, Vinciane; Lanari, Pierre; Goderis, Steven; Vandendael, Isabelle; Vanhaecke, Frank; Vidal, Olivier; Claeys, Philippe

    2013-11-01

    Chondrites are among the most primitive objects in the Solar System and constitute the main building blocks of telluric planets. Among the radiochronometers currently used for dating geological events, Sm-Nd and Lu-Hf are both composed of refractory, lithophile element. They are thought to behave similarly as the parent elements (Sm and Lu) are generally less incompatible than the daughter elements (Nd and Hf) during geological processes. As such, their respective average isotopic compositions for the solar system should be well defined by the average of chondrites, called Chondritic Uniform Reservoir (CHUR). However, while the Sm-Nd isotopic system shows an actual spread of less than 4% in the average chondritic record, the Lu-Hf system shows a larger variation range of 28% [Bouvier A., Vervoort J. D. and Patchett P. J. (2008) The Lu-Hf and Sm-Nd isotopic composition of CHUR: Constraints from unequilibrated chondrites and implications for the bulk composition of terrestrial planets. Earth Planet. Sci. Lett.273, 48-57]. To better understand the contrast between Sm-Nd and Lu-Hf systems, the REE and Hf distribution among mineral phases during metamorphism of Karoonda (CK) and Vigarano-type (CV) carbonaceous chondrites has been examined. Mineral modes were determined from elemental mapping on a set of five CK chondrites (from types 3-6) and one CV3 chondrite. Trace-element patterns are obtained for the first time in all the chondrite-forming minerals of a given class (CK chondrites) as well as one CV3 sample. This study reveals that REE are distributed among both phosphates and silicates. Only 30-50% of Sm and Nd are stored in phosphates (at least in chondrites types 3-5); as such, they are not mobilized during early stages of metamorphism. The remaining fraction of Sm and Nd is distributed among the same mineral phases; these elements are therefore not decoupled during metamorphism. Of the whole-rock total of Lu, the fraction held in phosphate decreases significantly

  2. The thermal and electrical properties of the promising semiconductor MXene Hf2CO2

    PubMed Central

    Zha, Xian-Hu; Huang, Qing; He, Jian; He, Heming; Zhai, Junyi; Francisco, Joseph S.; Du, Shiyu

    2016-01-01

    With the growing interest in low dimensional materials, MXenes have also attracted considerable attention recently. In this work, the thermal and electrical properties of oxygen-functionalized M2CO2 (M = Ti, Zr, Hf) MXenes are investigated using first-principles calculations. Hf2CO2 is determined to exhibit a thermal conductivity better than MoS2 and phosphorene. The room-temperature thermal conductivity along the armchair direction is determined to be 86.25~131.2 Wm−1 K−1 with a flake length of 5~100 μm. The room temperature thermal expansion coefficient of Hf2CO2 is 6.094 × 10−6 K−1, which is lower than that of most metals. Moreover, Hf2CO2 is determined to be a semiconductor with a band gap of 1.657 eV and to have high and anisotropic carrier mobility. At room temperature, the Hf2CO2 hole mobility in the armchair direction (in the zigzag direction) is determined to be as high as 13.5 × 103 cm2V−1s−1 (17.6 × 103 cm2V−1s−1). Thus, broader utilization of Hf2CO2, such as the material for nanoelectronics, is likely. The corresponding thermal and electrical properties of Ti2CO2 and Zr2CO2 are also provided. Notably, Ti2CO2 presents relatively lower thermal conductivity but much higher carrier mobility than Hf2CO2. According to the present results, the design and application of MXene based devices are expected to be promising. PMID:27302597

  3. The thermal and electrical properties of the promising semiconductor MXene Hf2CO2

    NASA Astrophysics Data System (ADS)

    Zha, Xian-Hu; Huang, Qing; He, Jian; He, Heming; Zhai, Junyi; Francisco, Joseph S.; Du, Shiyu

    2016-06-01

    With the growing interest in low dimensional materials, MXenes have also attracted considerable attention recently. In this work, the thermal and electrical properties of oxygen-functionalized M2CO2 (M = Ti, Zr, Hf) MXenes are investigated using first-principles calculations. Hf2CO2 is determined to exhibit a thermal conductivity better than MoS2 and phosphorene. The room-temperature thermal conductivity along the armchair direction is determined to be 86.25~131.2 Wm‑1 K‑1 with a flake length of 5~100 μm. The room temperature thermal expansion coefficient of Hf2CO2 is 6.094 × 10‑6 K‑1, which is lower than that of most metals. Moreover, Hf2CO2 is determined to be a semiconductor with a band gap of 1.657 eV and to have high and anisotropic carrier mobility. At room temperature, the Hf2CO2 hole mobility in the armchair direction (in the zigzag direction) is determined to be as high as 13.5 × 103 cm2V‑1s‑1 (17.6 × 103 cm2V‑1s‑1). Thus, broader utilization of Hf2CO2, such as the material for nanoelectronics, is likely. The corresponding thermal and electrical properties of Ti2CO2 and Zr2CO2 are also provided. Notably, Ti2CO2 presents relatively lower thermal conductivity but much higher carrier mobility than Hf2CO2. According to the present results, the design and application of MXene based devices are expected to be promising.

  4. The thermal and electrical properties of the promising semiconductor MXene Hf2CO2.

    PubMed

    Zha, Xian-Hu; Huang, Qing; He, Jian; He, Heming; Zhai, Junyi; Francisco, Joseph S; Du, Shiyu

    2016-01-01

    With the growing interest in low dimensional materials, MXenes have also attracted considerable attention recently. In this work, the thermal and electrical properties of oxygen-functionalized M2CO2 (M = Ti, Zr, Hf) MXenes are investigated using first-principles calculations. Hf2CO2 is determined to exhibit a thermal conductivity better than MoS2 and phosphorene. The room-temperature thermal conductivity along the armchair direction is determined to be 86.25~131.2 Wm(-1) K(-1) with a flake length of 5~100 μm. The room temperature thermal expansion coefficient of Hf2CO2 is 6.094 × 10(-6) K(-1), which is lower than that of most metals. Moreover, Hf2CO2 is determined to be a semiconductor with a band gap of 1.657 eV and to have high and anisotropic carrier mobility. At room temperature, the Hf2CO2 hole mobility in the armchair direction (in the zigzag direction) is determined to be as high as 13.5 × 10(3) cm(2)V(-1)s(-1) (17.6 × 10(3) cm(2)V(-1)s(-1)). Thus, broader utilization of Hf2CO2, such as the material for nanoelectronics, is likely. The corresponding thermal and electrical properties of Ti2CO2 and Zr2CO2 are also provided. Notably, Ti2CO2 presents relatively lower thermal conductivity but much higher carrier mobility than Hf2CO2. According to the present results, the design and application of MXene based devices are expected to be promising. PMID:27302597

  5. Mineralocorticoid receptor antagonists as diuretics: Can congestive heart failure learn from liver failure?

    PubMed

    Masoumi, Amirali; Ortiz, Fernando; Radhakrishnan, Jai; Schrier, Robert W; Colombo, Paolo C

    2015-05-01

    Despite significant improvements in diagnosis, understanding the pathophysiology and management of the patients with acute decompensated heart failure (ADHF), diuretic resistance, yet to be clearly defined, is a major hurdle. Secondary hyperaldosteronism is a pivotal factor in pathogenesis of sodium retention, refractory congestion in heart failure (HF) as well as diuretic resistance. In patients with decompensated cirrhosis who suffer from ascites, similar pathophysiological complications have been recognized. Administration of natriuretic doses of mineralocorticoid receptor antagonists (MRAs) has been well established in management of cirrhotic patients. However, this strategy in patients with ADHF has not been well studied. This article will discuss the potential use of natriuretic doses of MRAs to overcome the secondary hyperaldosteronism as an alternative diuretic regimen in patients with HF.

  6. Mineralocorticoid receptor antagonists as diuretics: Can congestive heart failure learn from liver failure?

    PubMed Central

    Ortiz, Fernando; Radhakrishnan, Jai; Schrier, Robert W.; Colombo, Paolo C.

    2014-01-01

    Despite significant improvements in diagnosis, understanding the pathophysiology and management of the patients with acute decompensated heart failure (ADHF), diuretic resistance, yet to be clearly defined, is a major hurdle. Secondary hyperaldosteronism is a pivotal factor in pathogenesis of sodium retention, refractory congestion in heart failure (HF) as well as diuretic resistance. In patients with decompensated cirrhosis who suffer from ascites, similar pathophysiological complications have been recognized. Administration of natriuretic doses of mineralocorticoid receptor antagonists (MRAs) has been well established in management of cirrhotic patients. However, this strategy in patients with ADHF has not been well studied. This article will discuss the potential use of natriuretic doses of MRAs to overcome the secondary hyperaldosteronism as an alternative diuretic regimen in patients with HF. PMID:25447845

  7. Critical Parameters for Obtaining Low Particle Densities on a Si Surface in an HF-Last Process

    NASA Astrophysics Data System (ADS)

    Alay, Josep-Lluís; Verhaverbeke, Steven; Vandervorst, Wilfried; Heyns, Marc

    1993-01-01

    A study was made on the relation between particle densities and the (remaining) degree of oxidation of a cleaned (100) Si surface following different HF-treatments (HF, HF/IPA, DI-rinse). A detailed comparison between (X-ray photoelectron spectroscopy) XPS and contact angle measurements of a water droplet with the Si surface shows that the latter method is sensitive to less than 1/10 of a SiO2 monolayer on the (100)Si surface. The results obtained with XPS point out that minute amounts of suboxides (a few percentage of a monolayer) are the dominant cause for particles. On the other hand, HF-dipping time and HF bath temperature are found to be the determinant parameters in an HF-last process. In addition the quality of the rinsing water as well as the initial roughness (Si vs polysilicon) play a major role.

  8. Microstructure and Corrosion Behavior of Hf-40 Wt Pct Ti Alloy in Nitric Acid Medium for Reprocessing Applications

    NASA Astrophysics Data System (ADS)

    Jayaraj, J.; Ravi, K. R.; Mallika, C.; Kamachi Mudali, U.

    2016-09-01

    The Hf-40 wt pct Ti (Hf-Ti) alloy was developed for neutron poison application in the spent nuclear fuel reprocessing plant. The furnace-cooled Hf-Ti sample exhibited the microstructure comprising equiaxed-α, lamellar-α, and feathery-α. The water-quenched Hf-Ti sample confirmed the presence of lath and internally twinned martensite. In comparison to the furnace-cooled sample, low corrosion current density and passivation current density values obtained for the water-quenched Hf-Ti in 6 M HNO3 at 298 K (25 °C) indicated better passivation ability. The martensitic structure exhibited high hardness (660 HV) and negligible corrosion rate in 6 M nitric acid at 298 K (25 °C). X-ray photoelectron spectroscopic (XPS) analysis confirmed that passivation behavior of this alloy was due to the protective passive film composed of TiO2 and HfO2.

  9. The study of single station inverting the sea surface current by HF ground wave radar based on adjoint assimilation technology

    NASA Astrophysics Data System (ADS)

    Han, Shuzong; Yang, Hua; Xue, Wenhu; Wang, Xingchi

    2016-10-01

    This paper introduces the assimilation technology in an ocean dynamics model and discusses the feasibility of inverting the sea surface current in the detection zone by assimilating the sea current radial velocity detected by single station HF ground wave radar in ocean dynamics model. Based on the adjoint assimilation and POM model, the paper successfully inverts the sea surface current through single station HF ground wave radar in the Zhoushan sea area. The single station HF radar inversion results are also compared with the bistatic HF radar composite results and the fixed point measured results by Annderaa current meter. The error analysis shows that acquisition of flow velocity and flow direction data from the single station HF radar based on adjoint assimilation and POM model is viable and the data obtained have a high correlation and consistency with the flow field observed by HF radar.

  10. Gas-phase reaction studies of dipositive hafnium and hafnium oxide ions: generation of the peroxide HfO2(2+).

    PubMed

    Lourenço, Célia; Michelini, Maria del Carmen; Marçalo, Joaquim; Gibson, John K; Oliveira, Maria Conceição

    2012-12-27

    Fourier transform ion cyclotron resonance mass spectrometry was used to characterize the gas-phase reactivity of Hf dipositive ions, Hf(2+)and HfO(2+), toward several oxidants: thermodynamically facile O-atom donor N(2)O, ineffective donor CO, and intermediate donors O(2), CO(2), NO, and CH(2)O. The Hf(2+) ion exhibited electron transfer with N(2)O, O(2), NO, and CH(2)O, reflecting the high ionization energy of Hf(+). The HfO(2+) ion was produced by O-atom transfer to Hf(2+) from N(2)O, O(2), and CO(2), and the HfO(2)(2+) ion by O-atom transfer to HfO(2+) from N(2)O; these reactions were fairly efficient. Density functional theory revealed the structure of HfO(2)(2+) as a peroxide. The HfO(2)(2+) ion reacted by electron transfer with N(2)O, CO(2), and CO to give HfO(2)(+). Estimates were made for the second ionization energies of Hf (14.5 ± 0.5 eV), HfO (14.3 ± 0.5 eV), and HfO(2) (16.2 ± 0.5 eV), and also for the bond dissociation energies, D[Hf(2+)-O] = 686 ± 69 kJ mol(-1) and D[OHf(2+)-O] = 186 ± 98 kJ mol(-1). The computed bond dissociation energies, 751 and 270 kJ mol(-1), respectively, are within these experimental ranges. Additionally, it was found that HfO(2)(2+) oxidized CO to CO(2) and is thus a catalyst in the oxidation of CO by N(2)O and that Hf(2+) activates methane to produce a carbene, HfCH(2)(2+).

  11. Designer HF-Based Fluorination Reagent: Highly Regioselective Synthesis of Fluoroalkenes and gem-Difluoromethylene Compounds from Alkynes

    PubMed Central

    2015-01-01

    Hydrogen fluoride (HF) and selected nonbasic and weakly coordinating (toward cationic metal) hydrogen-bond acceptors (e.g., DMPU) can form stable complexes through hydrogen bonding. The DMPU/HF complex is a new nucleophilic fluorination reagent that has high acidity and is compatible with cationic metal catalysts. The gold-catalyzed mono- and dihydrofluorination of alkynes using the DMPU/HF complex yields synthetically important fluoroalkenes and gem-difluoromethlylene compounds regioselectively. PMID:25260170

  12. Pentoxifylline Treatment in Acute Pancreatitis (AP)

    ClinicalTrials.gov

    2016