bluuebunny/crossref_metadata_2025_split huggingface dataset:
Azidoberyllate mit Adamantanstruktur: Synthese, IR‐Spektren und Kristallstrukturen von (Ph4P)2[Be4X4(μ‐N3)6] (X = Cl, Br)
Authors: Neumüller Bernhard , Dehnicke Kurt 
Published: February 2004

AbstractAzido Beryllates with Adamantan‐like Structures: Synthesis, IR Spectra, and Crystal Structures of (Ph4P)2[Be4X4(μ‐N3)6] (X = Cl, Br)The azido beryllates (Ph4P)2[Be4X4(μ‐N3)6] (X = Cl 1a, X = Br 1b) have been prepared by the reaction of Me3SiN3 with the halogeno beryllates (Ph4P)2[Be2Cl6] and (Ph4P)2[Be2Br6], respectively, in CH2Cl2 and CH2Br2 solution, respectively. Both complexes form moisture sensitive, colourless crystals, which are nonexplosive with respect to mechanical or thermal stress. They are characterized by IR spectroscopy and by crystal structure determinations. 1a and 1b crystallize isotypically in the space group C2/c with 12 formula units per unit cell. Whereas 1a was only refined to R1 = 0.13, which is caused by disordering, 1b could be refined to R1 = 0.066. The structures contain adamantanlike dianions [Be4X4(μ‐N3)6]2— with two symmetry nonequivalent individuals which differ only slightly from one another. The Be4N6 core is formed by bridging function of the α‐nitrogen atoms of the azide groups with BeN bond lengths of 172.5 and bond lengths Nα—Nβ = 123.2 pm and Nβ—Nγ = 113.1 pm on average in the structure of 1b.
On damping in two‐layer elastic‐viscoelastic media
Authors: Renardy M. 
Published: February 2004

AbstractWe consider one‐dimensional wave propagation through two layers consisting, respectively, of an elastic and a viscoelastic medium. We show that, if the instantaneous elastic modulus of the viscoelastic medium is infinite, then there exists a family of modes with frequencies going to infinity, but damping rates going to zero. Hence the overall rate of damping is not exponential. On the other hand, there is a possibility of faster than exponential damping (i.e., the damping rate goes to infinity with frequency) if the elastic moduli of the two media are matched and the derivative G′(0) of the relaxation modulus of the viscoelastic medium is ‐∞.
A computer‐assisted instability proof for the Orr‐Sommerfeld equation with Blasius profile
Authors: Lahmann J.‐R. , Plum M. 
Published: February 2004

AbstractThe Orr‐Sommerfeld equation is one of the governing equations of hydrodynamic stability. Mathematically, it constitutes a non‐selfadjoint eigenvalue problem. Depending on its spectrum being contained in the right complex half‐plane or not, the underlying flow is stable or unstable under some given perturbation. Here, we focus on the Blasius profile modelling a flow along a wall. We present a computer‐assisted method for computing eigenvalue enclosures for such non‐selfadjoint problems. As a specific result, for a particular parameter constellation in the Orr‐Sommerfeld equation (often used as test example in the engineering literature), we enclose an eigenvalue in a circle which is completely contained in the left half‐plane. This constitutes the first rigorous proof of instability for the Orr‐Sommerfeld equation with Blasius profile.
Second order methods for boundary control of the instationary Navier‐Stokes system
Authors: Hinze M. , Kunisch K. 
Published: February 2004

AbstractSecond order methods for open loop optimal boundary control problems governed by the instationary Navier‐Stokes system are investigated. A general analytic framework is developed which allows an elegant representation of first and second order derivatives of the objective functional and of the state equations. Moreover a second order sufficient optimality condition is proved which guarantees local quadratic convergence of Newton's method.
Asymptotics of self‐intersecting loop solutions of the pendant drop equations
Authors: O'Brien S.B.G. 
Published: February 2004

AbstractWe construct asymptotic solutions for loop‐like self intersecting mathematical solutions of the Laplace‐Young capillary equation which was originally derived to model liquid rise in capillary tubes. We show that each successive loop has a complicated asymptotic structure which is resolved using the method of matched asymptotic expansions.
On the convergence of the Newton iteration
Authors: Veselić K. 
Published: February 2004

AbstractWe give a new class of convergence criteria for the classical Newton method for the equation f(x) = 0. We prove the global convergence, if the function f is the gradient of a uniformly convex function, while the convergence in the general case is still open. Our convergence condition consists of only one bound with a constant, which is shown to be sharp. We apply our result to a generic variational problem as well as to uniformly diagonally dominant Hessians. The convergence result is extended to the cases where the derivative is defined merely as a distribution.
A new relationship for the experimental‐analytical solution of the axisymmetric thermoelasticity problem
Authors: Ainola L. , Aben H. 
Published: February 2004

AbstractThe following inverse problem of axisymmetric thermoelasticity is considered: stresses σz and σrz are determined experimentally but the temperature distribution is not known; the stresses σr and σθ are to be determined. By eliminating temperature from the compatibility equations and using the equilibrium equations, a new relationship between the stress components for the axisymmetric thermoelasticity problem has been derived. Using this relationship, a closed form solution of the problem has been obtained.
Specialist care of heart failure improves appropriate pharmacotherapy at the expense of greater polypharmacy and drug‐interactions
Authors: Ledwidge Mark , Travers Bronagh , Ryder Mary , Ryan Enda , McDonald Kenneth 
Published: February 2004

AbstractBackground:There is growing concern at the nature and extent of polypharmacy in heart failure (HF), which may be associated with increased drug interactions, adverse drug effects and a poor understanding of and compliance with therapy.Aims:This study evaluates polypharmacy in a relatively unselected community heart failure population following emergency admission and determines the impact of an in‐hospital, specialist heart failure care programme on appropriate pharmacotherapy, polypharmacy and drug interactions.Methods:We analysed the medication profiles of 91 consecutive patients with an emergency admission for HF to our institution on admission and discharge. The numbers of inappropriate medicines, inappropriate dosages and omitted medicines according to guidelines were recorded. Medication profiles were analysed for potential drug–drug, drug–liver and drug–kidney interactions using standard criteria.Results:In the study population, average age 71.1±10.4 years, 65.9% were male, 68.1% had left ventricular systolic dysfunction and the average ejection fraction on transfer to the specialist HF service was 38±13%. A total of 66 inappropriate medicines, 107 omitted medicines and 37 inappropriate dosage regimens were identified in the cohort on admission. These figures had dropped to 31, 33 and 19, respectively, on discharge, with per patient averages decreasing significantly (all P<0.0001). However, polypharmacy and potential drug interactions increased by 33% and 62%, respectively, from admission to discharge (P<0.0001) as did drug–kidney interactions and drug–liver interactions. Only ischemic aetiology and hypercholesterolaemia predicted polypharmacy in this cohort on discharge, whereas age, sex, renal function and heart failure type did not.Conclusions:Specialist care of heart failure following emergency admission results in more appropriate pharmacotherapy of heart failure. However, increased polypharmacy and drug–interactions are an inevitable consequence independent of age, sex and renal function. We advocate a practice of systematic evaluation of polypharmacy in all heart failure patients to identify potential problems and modify therapy where appropriate.
Improved systolic and diastolic myocardial function with intracoronary pyruvate in patients with congestive heart failure
Authors: Hermann Hans‐Peter , Arp Jordis , Pieske Burkert , Kögler Harald , Baron Steffen , Janssen Paul M.L. , Hasenfuss Gerd 
Published: February 2004

AbstractBackground:Pyruvate increases myocardial performance in isolated myocardium and improves hemodynamics in patients with congestive heart failure.Aims:To investigate the influence of pyruvate on detailed parameters of systolic and diastolic left ventricular (LV) function.Methods and Results:In patients with heart failure due to dilated cardiomyopathy (LVEF 30±4%, n=9) pyruvate was infused intracoronarily. LV function was analysed before, during and after application of different pyruvate concentrations using a LV‐micromanometer catheter. LV volumes were determined using cine ventriculography. Pyruvate increased maximum rate of LV isovolumic pressure rise (Peak +dP/dt) from 802±106 to 1125±103 mmHg/s (P<0.05). Left ventricular end‐diastolic pressure declined in parallel from 17±2 to 12±2 mmHg (P<0.05) and heart rate decreased from 79±4 to 72±5 min−1 (P<0.05). Stroke volume index increased from 34±4 to 43±6 ml/m2 (P<0.05), end‐diastolic LV volume remained unchanged, thus left ventricular ejection fraction increased with pyruvate from 30±4 to 39±4% (P<0.05). Maximum rate of LV isovolumic pressure decline (Peak −dP/dt) was significantly increased with pyruvate (from 794±94 to 980±108 mmHg/s; P<0.05) and mean arterial pressure increased from 80±5 to 88±4 mmHg (P<0.05). Discontinuation of pyruvate resulted in immediate reversibility of its effects.Conclusion:Intracoronary pyruvate improves systolic and diastolic myocardial function and increases ejection fraction without increasing heart rate. Pyruvate thus exhibits the profile of a favourable inotropic agent, however, further investigation for the treatment of patients with acute heart failure is mandatory.
Long‐term effects of non‐excitatory cardiac contractility modulation electric signals on the progression of heart failure in dogs
Authors: Morita Hideaki , Suzuki George , Haddad Walid , Mika Yuval , Tanhehco Elaine J. , Goldstein Sidney , Ben‐Haim Shlomo , Sabbah Hani N. 
Published: February 2004

AbstractObjective:We previously showed that acute delivery of non‐excitatory cardiac contractility modulation (CCM) electric signal during the absolute refractory period improved LV function in dogs with chronic heart failure (HF). In the present study we examined the long‐term effects of CCM signal delivery on the progression of LV dysfunction and remodeling in dogs with chronic HF.Methods:Chronic HF was produced in 12 dogs by multiple sequential intracoronary microembolizations. The CCM signal was delivered using a lead implanted in the distal anterior coronary vein. A right ventricular and a right atrial lead were implanted and used for timing of CCM signal delivery. In six dogs, CCM signals were delivered continuously for 6 h daily with an average amplitude of 3.3 V for 3 months. Six HF dogs did not have leads implanted and served as controls.Results:In control dogs, LV end‐diastolic volume (EDV) and LV end‐systolic volume (ESV) increased (64±5 ml vs. 75±6 ml, P=0.003; 46±4 ml vs. 57±4 ml, P=0.003; respectively), and ejection fraction (EF) decreased (28±1% vs. 23±1%, P=0.001) over the course of 3 months of follow‐up. In contrast, CCM‐treated dogs showed a smaller increase in EDV (66±4 vs. 73±5 ml, P=0.01), no change in ESV, and an increase in EF from 31±1 to 34±2% (P=0.04) after 3 months of therapy.Conclusions:In dogs with HF, long‐term CCM therapy prevents progressive LV dysfunction and attenuates global LV remodeling. These findings provide compelling rationale for exploring the use of CCM for the treatment of patients with chronic HF.
The epidemiological enigma of heart failure with preserved systolic function
Authors: Thomas Martin D. , Fox Kevin F. , Coats Andrew J.S. , Sutton George C. 
Published: February 2004

AbstractBackground:Current epidemiological evidence suggests that the prevalence of preserved systolic function in patients with heart failure varies widely from 13 to 74%. This inconsistency suggests a lack of consensus as to what this condition really is and how it has been characterised for epidemiological studies.Aims:In this review, we summarise and discuss the current understanding of the epidemiology of heart failure with preserved systolic function and the challenges that this raises.Methods:Studies were identified from Medline and Embase Literature Database searches using the subject headings heart failure, diastolic heart failure, epidemiology, incidence, prevalence, diagnosis, prognosis and mortality.Results:Sixty‐one studies of congestive heart failure with preserved systolic function were reviewed. There is great diversity in the criteria used to determine whether heart failure is present, the patient population, the setting of the study and methods of evaluating left ventricular function. This makes epidemiological studies of prevalence, morbidity and mortality impossible to compare.Conclusions:The diagnosis of this syndrome might be better defined in terms of symptoms, elevated neuro hormones and impaired cardiac workload. This would allow accurate identification of cases so that further research could be conducted to measure outcome and assess therapeutic benefit.
NT‐brain natriuretic peptide levels in pleural fluid distinguish between pleural transudates and exudates
Authors: Tomcsányi János , Nagy Erzsébet , Somlói Miklós , Moldvay Judit , Bezzegh Attila , Bózsik Béla , Strausz János 
Published: February 2004

AbstractBackground:Pleural effusion is not pathognomic and distinguishing between transudates and exudates often presents a diagnostic dilemma. The purpose of our study was to examine whether the inclusion of pleural fluid brain natriuretic peptide (BNP) measurement into the analysis improves the diagnostic accuracy of pleural effusion.Methods:The pleural effusion of 14 patients with CHF (group A) and 14 subjects with different pleural pathology (group B) were analyzed. Samples of pleural fluid and serum were obtained from all patients on admission and biochemical analysis, bacterial and fungal culture, acid‐fast bacilli smear and culture and cytology were performed on the pleural fluid. In vitro quantitative determination of N‐terminal pro‐Brain natriuretic peptide (NT‐proBNP) in serum and pleural fluid were performed by electrochemiluminescence immunoassay proBNP method on an Elecsys 2010 (Roche) analyzer.Results:The median NT‐proBNP levels in groups A and B were 6295 pg/ml and 276 pg/ml, respectively: (P=0.0001). There was no overlap between the two groups. While the Light's criteria had a sensitivity of 93% and specificity of 43% for transudates, the pleural fluid NT‐proBNP level accurately differentiated between the two groups.Conclusions:The pleural NT‐proBNP levels were elevated in all patients who had transudate. Therefore if the NT‐proBNP levels of pleural effusion are within the normal range, transudate resulting from congestive heart failure can be ruled out. Our results suggest that the inclusion of pleural fluid NT‐proBNP measurement in the routine diagnostic panel would enhance discrimination among the different causes of pleural effusions.
Application of NT‐proBNP and BNP measurements in cardiac care: a more discerning marker for the detection and evaluation of heart failure
Authors: Seino Yoshihiko , Ogawa Akio , Yamashita Teruyo , Fukushima Masato , Ogata Ken‐ichi , Fukumoto Hiroko , Takano Teruo 
Published: February 2004

AbstractBackground:Measurement of brain natriuretic peptide (BNP) has become a potent diagnostic aid as a means of identifying patients with systolic or diastolic dysfunction. Due to better stability in circulating blood, we reasoned that measurement of N‐terminal proBNP (NT‐proBNP) may be a more discerning marker for the detection and evaluation of chronic heart failure.Methods:The relationships between plasma concentrations of NT‐proBNP and BNP, and aetiology, New York Heart Association (NYHA) classification, and left ventricular ejection fraction (LVEF) were analyzed in 105 patients with chronic heart failure. Sixty‐seven healthy volunteers were studied as the controls.Results:Both NT‐proBNP and BNP showed progressive increases (P<0.001) in proportion to the NYHA classification; the increment of NT‐proBNP was larger than that of BNP. Elevated NT‐proBNP significantly correlated with BNP (r=0.737, P<0.001). Receiver operating characteristics analysis to detect LVEF<40% showed similar values (area under the curve, AUC: NT‐proBNP 0.754 vs. BNP 0.770), however, AUC to detect LVEF<50% tended to be greater for NT‐proBNP than that for BNP (NT‐proBNP 0.820 vs. BNP 0.794).Conclusion:NT‐proBNP may be a more discerning marker for the detection and evaluation of heart failure than BNP.
Value of N‐terminal pro brain natriuretic peptide in the elderly: data from the prospective Copenhagen Hospital Heart Failure study (CHHF)
Authors: Nielsen Olav Wendelboe , Kirk Vibeke , Bay Morten , Boesgaard Søren , Nielsen Henrik 
Published: February 2004

We describe the value of Nt‐proBNP in relation to cardiac normality and risk of major adverse cardiac events (MACE) in consecutive hospitalised patients below and above 75 years of age. Method: During a 10 month period 2224 consecutive patients, admitted to all departments in a general city hospital, had a full cardiac examination and were prospectively followed for 1 year. We identified a normal group (without obvious heart disease) and a group with MACE (significant heart disease at admission or a cardiac event within the following 90 days). NT‐proBNP measurements were done using an ELISA—a two‐step sandwich assay with streptavidin coated microtitre plates. Results: The age dependent 90th percentiles of Nt‐proBNP in the normal group were approximately 3 times higher than values reported in previous community studies. Elderly patients had 3‐fold higher absolute cut off values than did patients under the age of 75 years. One‐hundred‐and‐sixteen patients had a MACE, and areas under the receiver operating curve (ROC) to predict a MACE were 0.83 (from 40 to 59 years), 0.82 (60 to 74) and 0.79 (from 75 years). In younger patients, the upper limit of Nt‐proBNP in normal patients was similar to the value, which defined the top quintile of risk. In patients aged greater than 75 years the predictive cut point included more than 40% of the population.Conclusion:Nt‐proBNP was useful at all ages but specificity was slightly lower in the elderly. Cut off values in hospitalised cardiac normal patients are approximately three times higher than community derived values.
Use of NT‐proBNP in routine testing and comparison to BNP
Authors: Pfister R. , Scholz M. , Wielckens K. , Erdmann E. , Schneider C.A. 
Published: February 2004

AbstractObjectives:B‐type natriuretic peptide (BNP) is a strong diagnostic predictor of left‐ventricular (LV)‐dysfunction. Recently, the aminoterminal portion of pro‐BNP (NT‐proBNP) has been introduced, which could be even more sensitive because of its longer half‐life. The aim of this study was to evaluate the new marker NT‐proBNP within a large, heterogeneous population of patients with suspected cardiovascular disease at risk of cardiovascular dysfunction and to compare it with the established diagnostic parameter BNP.Subjects and methods:NT‐proBNP and BNP were measured in 339 hospitalised patients undergoing diagnostic angiography (median age 66 years, 244 male vs. 95 female).Results:Median values of NT‐proBNP increased with worsening LV‐dysfunction and higher NYHA class. The area under the receiver operator characteristics curve (AUC) of NT‐proBNP for detecting severe systolic dysfunction or for detecting any systolic LV‐dysfunction was 0.83 and 0.77, respectively. The latter improved (AUC=0.81) when patients with clinically relevant heart disease like valvular dysfunction were included, independent of the haemodynamic values. Compared to BNP, NT‐proBNP tended to be more accurate in identifying lesser degrees of LV‐dysfunction.Conclusions:Even after optimisation of target criteria, there was still a substantial overlap of NT‐proBNP values between patients with and without relevant heart disease. Therefore, NT‐proBNP is not suitable as a screening test for LV‐dysfunction in the community. Nevertheless, because of its good negative predictive value, NT‐proBNP could be an easy and effective tool to rule out severe systolic LV‐dysfunction in high risk patients. No clinically significant advantage of BNP testing could be found.
N‐terminal proBNP and mortality in hospitalised patients with heart failure and preserved vs. reduced systolic function: data from the prospective Copenhagen Hospital Heart Failure Study (CHHF)
Authors: Kirk V. , Bay M. , Parner J. , Krogsgaard K. , Herzog T.M. , Boesgaard S. , Hassager C. , Nielsen O.W. , Aldershvile J. , Nielsen H. 
Published: February 2004

Preserved systolic function among heart failure patients is a common finding, a fact that has only recently been fully appreciated. The aim of the present study was to examine the value of NT‐proBNP to predict mortality in relation to established risk factors among consecutively hospitalised heart failure patients and secondly to characterise patients in relation to preserved and reduced systolic function.Material:At the time of admission 2230 consecutively hospitalised patients had their cardiac status evaluated through determinations of NT‐proBNP, echocardiography, clinical examination and medical history. Follow‐up was performed 1 year later in all patients.Results:161 patients fulfilled strict diagnostic criteria for heart failure (HF). In this subgroup of patients 1‐year mortality was approximately 30% and significantly higher as compared to the remaining non‐heart failure population (approx. 16%). Using univariate analysis left ventricular ejection fraction (LVEF), New York Heart Association classification (NYHA) and plasma levels of NT‐proBNP all predicted mortality independently. However, regardless of systolic function, age and NYHA class, risk‐stratification was provided by measurements of NT‐proBNP. Having measured plasma levels of NT‐proBNP, LVEF did not provide any additional prognostic information on mortality among heart failure patients (multivariate analysis).Conclusion:The results show that independent of LVEF, measurements of NT‐proBNP add additional prognostic information. It is concluded that NT‐proBNP is a strong predictor of 1‐year mortality in consecutively hospitalised patients with heart failure with preserved as well as reduced systolic function.
NT‐proBNP in heart failure: therapy decisions and monitoring
Authors: Richards Mark , Troughton Richard W. 
Published: February 2004

AbstractWith increasing cardiac dysfunction, a complex neurohormonal response results in increasing circulating levels of an array of plasma hormones. Increments in plasma levels of atrial natriuretic peptide (ANP) and B‐type natriuretic peptide (BNP) and their amino‐terminal congeners are more closely related to cardiac structure and function and to cardiovascular prognosis than changes in other plasma neurohormones. Reports suggest that changes in plasma BNP levels in the course of treatment of acutely decompensated heart failure provide a more powerful prognostic indicator of the likelihood of survival or recurrent decompensation than symptomatic assessment. This observation requires a randomised controlled trial in which changes in peptide levels determine aggression and duration of in‐patient therapy in order to establish whether this indicator can improve results from management of acute in‐patient heart failure. Plasma BNP or NT‐proBNP is a powerful independent predictor of mortality and morbidity in long‐term follow‐up of heart failure cohorts. In addition, it appears likely to be a good predictor of beneficial response to the addition of beta blockade to anti‐heart failure pharmacotherapy. Finally, adjustment of therapy for heart failure according to serial measurements of NT‐proBNP promises to improve outcomes in comparison with adjusting therapy according to unassisted clinical acumen.