Ultra-broadband EPR spectroscopy in field and frequency domains.

Electron paramagnetic resonance (EPR) is a powerful technique to investigate the electronic and magnetic properties of a wide range of materials. We present the first combined terahertz (THz) field and frequency domain electron paramagnetic resonance (HFEPR/FDMR) spectrometer designed to investigate the electronic structure and magnetic properties of molecular systems, thin films and solid state materials in a very broad frequency range of 85-1100 GHz. In this paper, we show high resolution frequency-field (Zeeman) maps (170-380 GHz by 0-15 T) recorded on two single-molecule magnets, [Mn2(saltmen)2(ReO4)2] and [Mn2(salpn)2(H2O)2](ClO4)2, which give direct access to the field-dependence of the energy level diagram. Furthermore, supression of standing waves in the described system and the sensitivity in field and frequency domain operations is evaluated and discussed.

Cyclotron motion in the vicinity of a Lifshitz transition in graphite.

Graphite, a model (semi)metal with trigonally warped bands, is investigated with a magnetoabsorption experiment and viewed as an electronic system in the vicinity of the Lifshitz transition. A characteristic pattern of up to 20 cyclotron resonance harmonics has been observed. This large number of resonances, their relative strengths and characteristic shapes trace the universal properties of the electronic states near a separatrix in momentum space. Quantum-mechanical perturbative methods with respect to the trigonal warping term hardly describe the data which are, on the other hand, fairly well reproduced within a quasiclassical approach and conventional band structure model. Trigonal symmetry is preserved in graphite in contrast to a similar system, bilayer graphene.

Co(II)-Based single-ion magnets with 1,1'-ferrocenediyl-bis(diphenylphosphine) metalloligands.

Herein, we report on investigations of magnetic and spectroscopic properties of three heterobimetallic Fe(ii)-Co(ii) coordination compounds based on the tetracoordinate {CoP2X2} core encapsulated by dppf metalloligand, where X = Cl (1), Br (2), I (3), dppf = 1,1'-ferrocenediyl -bis(diphenylphosphine). The analysis of static magnetic data has revealed the presence of axial magnetic anisotropy in compounds (1) and (2) and this was further confirmed by high-frequency electron spin resonance (HF-ESR) spectroscopy. Dynamic magnetic data confirmed that (1) and (2) behave as field-induced Single-Ion Magnets (SIMs). Together with bulk studies, we have also tested the possibility of depositing (2) as thick films on Au(111), glass, and polymeric acetate by drop-casting as well as thermal sublimation, a key aspect for the development of future devices embedding these magnetic objects.

Nuclear receptors gene polymorphisms and risk of restenosis and clinical events following coronary stenting.

INTRODUCTION: Hereditary factors connected with inflammation and fibroproliferation may play important role in restenotic process after coronary stenting. Peroxisome proliferator-activated receptors (PPAR) and retinoic X receptors (RXR) regulate the transcription of crucial genes involved in the glucose and lipid metabolism, inflammation and cell differentiation. METHODS: In our angiographic and clinical study we assessed the association of gene polymorphisms of L162V for PPAR-alpha, C161T for PPAR-gamma and A(39526)AA for RXR-alpha with the risk of restenosis and cardiac events after coronary stenting. Primary endpoint was diameter stenosis > or = 50% at follow-up angiography. Secondary endpoints were death, myocardial infarction and/or target lesion revascularisation at 12 months, and clinical restenosis. The results were adjusted for known predictors of restenosis. The genotypes were analysed by polymerase chains reaction (PCR) and restriction fragment length polymorphism (RFLP) methods. RESULTS: Control angiography was performed in 477 of 565 patients (84.4%) with following restenosis rates in genotype subgroups: CC 29.0% vs GC/GG 22.6% (p = 0.33) in L162V, CC 29.9% vs TC/TT 24.6% (p = 0.24) in C161T and A/A 26.9% vs A/AA + AA/AA 35.0% (p = 0.14) in A(39526)AA polymorphisms. The T allele ofC161T polymorphism was associated with lower frequency of clinical restenosis (p = 0.015). CONCLUSION: We could not find an association of L162V PPAR-alpha, C161T PPAR-gamma and A(39526)AA RXR-alpha gene polymorphisms with angiographic in-stent restenosis or major cardiac events. However, we found the relationship between C161T PPAR-gamma polymorphism and clinical restenosis deserving further study.

[Factors related to NT-proBNP values in haemodynamically stable patients with normal systolic function of the left ventricle]. / Faktory se vztahem k hodnotám NT-proBNP u hemodynamicky stabilních pacientu s normální systolickou funkcí levé komory.

INTRODUCTION: Increased values ofnatriuretic peptides are considered prognostically significant in normal population with respect to mortality and the incidence of cardiovascular events, regardless of the left ventricular function. The objective of the study is to point out the factors related to NT-proBNP values in patients without the heart failure syndrome and with normal left ventricular systolic function. METHODS: The group consisted of 290 elective patients aged between 50 and 82, with the mean age of 62 years, of whom 47% were women. The enrolled patients were heamodynamically stable, without a history of MI, with a normal left ventricular systolic function and with the serum creatinine level < 150 micromol/l. On the same day, the following procedures were performed: left heart catheterisation, NT-proBNP sampling and echocardiographic examination. Diabetes mellitus, hypertension, coronary heart disease, body mass index, age, sex, left ventricular end-diastolic pressure and aortic pulse pressure were chosen as factors with possible impact on the level of NT-proBNP. We used echo parametres to assess the size of the left ventricle, the left ventricular mass index and the presence of left ventricular diastolic function. RESULTS: The median of NT-proBNP was 110 pg/ml (min. 11; max. 1,943 pg/ml), and higher values were recorded for 116 (i.e. 40%) of the total number of patients. Based on the above-referred factors, a significant relation was demonstrated between NT-proBNP and age (p < 0.01), sex (p < .01), BMI (p = 0.03), left ventricular size (p = 0.02), left ventricular mass index (p = 0.01), and aortic pulse pressure (p < 0.01). CONCLUSION: The study has shown that the level of NT-proBNP in patients does not solely depend on the haemodynamic status and left ventricular function, but is related to many other risk factors of cardiovascular mortality and morbidity.

Multi-frequency rapid-scan HFEPR.

Gaining access to electron spin dynamics at (sub-)THz frequencies is highly challenging. However, this information is highly relevant for the understanding and development of spin polarization agents in dynamic nuclear polarization methods and single-molecule magnets for quantum computation. Here we demonstrate the first rapid-scan EPR experiment in 200 GHz frequency region. A voltage controlled oscillator (VCO) generated fast sinusoidal frequency sweeps with scan rates up to 3×105 THz/s after the frequency multiplication, which is equal to 107 T/s in field representation. Such high scan rates provide access to extremely short relaxation times T2=2π×sweeprate-0.5≈1 ns. The absence of a microwave cavity allowed us to perform multi-frequency experiments in the 170-250 GHz range. A further advantage of a cavity-less approach is the possibility to use vast sweeps, which in turn, allows the deconvolution using a linear sweep function. The deconvoluted spectra obtained with this method are identical to the slow-rate spectrum. We find spin-spin relaxation times of several nanoseconds for pure LiPc samples in this frequency range. These values cannot be obtained by means of conventional pulsed EPR methods.

[Is the left ventricle enddiastolic pressure pathological in the older population?]. / Je zvýsený enddiastolický tlak v levé komore u populace starsího veku patologický?

INTRODUCTION: The percentage of older population has significantly increased in the recent decades. Morphologic and functional changes of the cardiovascular system go together with ageing. The aim of the study should show the correlation between the age and left ventricular enddiastolic pressure (LVDEP) value. METHODS: 106 patients of the age from 23 to 79 years without an organic heart disease and the history of hypertension underwent elective coronary angiography including left ventricle angiography between 1999 and 2002. LVEDP was obtained as an average value from 8 consecutive beats without extrasystoles. According to the relation between increased relative frequency of LVEDP and age patients were divided into two groups: 50 years and older (80 patients) and younger than 50 years (26 patients). RESULTS: An average LVEDP value in older population versus younger population was 12.1 +/- 5.0 mm Hg vs 8.9 +/- 3.4 mm Hg, p < 0.05. Increased LVEDP in yonger population was found in only 11.5 % vs 46.2 % in older group, p < 0.01 and the LVEDP was age dependent, p < 0.05. CONCLUSIONS: In compliance with about mentioned results we suppose that the age is a factor with impact to LVEDP value. LVEDP values > 12 mm Hg in older population may not be pathological and probably are due to the left ventricle diastolic dysfunction in consequence with ageing.

Magneto-optical investigations of molecular nanomagnet monolayers.

We report field-dependent magnetization measurements on monolayers of [Dy(Pc)2] on quartz, prepared by the Langmuir-Blodgett technique. The films are thoroughly characterized by means of X-ray reflectivity and atomic force microscopy. The magnetisation of the sample is measured through the magnetic circular dichroism of a ligand-based electronic transition.

A Mn(iii) single ion magnet with tridentate Schiff-base ligands.

Single ion magnet behaviour is reported for a mononuclear Mn(iii) ion with tridentate Schiff-base ligands which exhibits a tetragonal Jahn-Teller elongation along the Namine-Mn-Namine axis and crystallises with two crystallographically distinct Mn(iii) cations (unit A and unit B). While magnetic measurements show a large and negative axial zero-field splitting (D = -4.73 cm(-1)), HF-EPR reveal two distinct large axial Ds (D = -4.60 cm(-1) for unit A and D = -4.18 cm(-1) for unit B), thus resulting in the largest D known to date for a Mn(iii) single ion magnet. AC magnetic measurements at 2000 Oe allowed determination of the energy barrier for spin reversal (10.19 K) and spin reversal relaxation time (1.476 × 10(-6) s) for the Mn(iii) ion. Computational studies were used to characterise the electronic structure and substantiate the zero field splitting in the Mn(iii) complex.

Effects of bilateral orbital decompression by an endoscopic endonasal approach in dysthyroid orbitopathy.

AIMS: The efficacy of endoscopic endonasal orbital decompression in dysthyroid orbitopathy was analysed. METHODS: In 21 consecutive cases of bilateral operation short term (10 (SD 6) days after operation) and long term (156 (12) days after operation) results were recorded. RESULTS: Short term results showed that vision of the more affected eye improved from a mean of 0.35 to 0.59; vision improved in all but one eye which remained unchanged. In the fellow eyes mean visual acuity improved from 0.6 to 0.7; three of these eyes showed a decrease. Mean proptosis returned from 23.0 mm to 20.0 mm. As to motility the mean abductive capacity decreased from 5.5 mm to 4.0 mm of monocular excursion, whereas adduction increased from 7.5 mm to 8.5 mm. Upgaze and downgaze did not show any major change. The mean angle of horizontal squint shifted from 7.5 degrees of convergence to 15.5 degrees while no significant vertical or cyclorotational deviation was induced. These immediate postoperative results proved to be stable for the period of long term follow up with only slight changes. No significant bleeding or specific otorhinolaryngological complication without resolve occurred intraoperatively or perioperatively. CONCLUSION: This method is believed to be superior to non-endoscopic techniques because it avoids external scars and antral pain. With regard to the relief of intraorbital pressure, the technique gives good results for visual acuity improvement, but in proptosis reduction the method is not as efficient as external or combined procedures. There seems to be no difference when compared with other approaches in induction of horizontal squint. The method has a protective long term effect against the recurrence of compressive optic neuropathy.

Continuous intratympanic infusion of gentamicin via a microcatheter in Menière's disease.

Between 1995 and 1998, 11 patients with disabling Menière's disease were treated at our institution with a continuous gentamicin infusion into the middle ear via a microcatheter. The patients had frequent attacks of vertigo and vomiting (functional levels 3-5). Hearing threshold on the affected side was significantly worse than on the healthy side (stage 4+5). Gentamicin was applied by a high-precision insulin pump with a flow rate of 40 mg per day directly in front of the round window. Application was stopped as soon as signs of vestibular affection appeared. A good overall control of vertiginous spells was achieved in 8 patients. Eight patients experienced complete hearing loss on the affected side, 1 experienced a slight worsening, and 1 had no hearing change. There was no correlation between the cumulative gentamicin dosage and the hearing loss. Our findings show that in terms of hearing loss and hospitalization time the continuous gentamicin application is inferior to other applications presented in the literature.

[Implantation of coronary stents in reperfusion therapy in acute myocardial infarct]. / Implantace koronárních stentu pri reperfuzní lécbe akutního infarktu myokardu.

BACKGROUND: Primary coronary angioplasty was accepted as a method of choice in the reperfusion treating strategy of the ST elevation acute myocardial infarction. Since 1995, when the very good results of the stent implantation in patients with acute myocardial infarction were published, there has been a general trend to more stenting also in the Czech Republic. AIM: The analysis of the effectivety and safety of the coronary stent implantation in acute myocardial infarction. METHODS: Prospective analysis of the patients with ST elevation acute myocardial infarction treated with primary coronary angioplasty with one coronary stent implantation at least in the period I/2000-XII/2000. RESULTS: In the above mentioned period the authors carried out the total of 116 primary coronary angioplasties in 116 patients with ST elevation acute myocardial infarction. Balloon angioplasty only was done in 27 patients (23.3%) only, at least one stent was implanted in 89 patients (76.7%). The average procedure time was 58 +/- 27.2 mins, fluoroscopy 10.6 +/- 6.6 mins, sciagraphy 1.8 +/- 0.7 mins. Primary angiographical result was optimal in 82 cases (92.2%) with achieving TIMI flow 3, in 5 cases (5.6%) there was slower perfusion of the infarcted artery observed with TIMI flow 2 and in 2 cases (2.2%) the authors were unsuccessful with final TIMI flow 0-1. Coronary stents were implanted in 13 cases (13.8%) without predilatation as so called "direct stenting", in 19 cases (20.2%) the planned or "elective" stenting was done, in 47 cases (50%) the suboptimal result after balloon angioplasty only was the reason for stent implantation and in 15 cases (16%) it was rescue "bail-out" stenting in complications of the balloon angioplasty only or if the result after balloon angioplasty was unsuccessful. Primary angiographical success of the stented lesion was 100% and in 14 cases (15.7%) the abciximab as a representative of IIb/IIIa platelet blockers was given. Periprocedural complications (up-to 24 hours after the procedure) in the stented group of patients occurred in 2 cases (2.2%), further serious in-hospital cardiovascular complications occurred in another 4 cases (4.4%). The total of 5 patients (5.5%) died in the hospital, out of which 4 patients (4.4%) died due to the primary cardiogennic shock and 1 patient (1.1%) admitted in pulmonary oedema died due to the heart failure progression. Excluding patients primary in cardiogennic shock the in-hospital mortality was 1.2% only. Hospital mortality in the group of patients treated with primary balloon angioplasty only was 3.7% (1 patient). CONCLUSION: At present the coronary artery stenting is safe and highly effective method in acute myocardial infarction treatment.

[Glycoprotein IIb/IIIa platelet blockers in acute myocardial infarct treated with primary coronary angioplasty]. / Gp IIb/IIIa blokátory desticek u akutního infarktu myokardu léceného primární koronární angioplastikou.

BACKGROUND: Primary coronary angioplasty is at present accepted as the most effective reperfusion treatment strategy of the ST elevation acute myocardial infarction. The optimum approach appears to be combination of the interventional technique (mechanical reperfusion) with aggressive pharmacological treatment aimed at the platelets. Intravenous blockers of the glycoprotein receptors IIb/IIIa together with acetylsalicylic acid have the additive antiaggregant effect and are used more frequently as adjunctive therapy by coronary interventions in patients with acute coronary syndromes and the acute myocardial infarction. AIM: The assessment of safety and effectiveness of the IIb/IIIa platelet blockers in patients indicated to primary coronary angioplasty. METHODS: Since 1st January 2000 to 30th June 2001 the authors carried out the total of 912 coronary angioplasties in their cathlab, from which in 195 cases (21.4%) the primary angioplasty in acute ST elevation myocardial infarction was conducted. IIb/IIIa blockers were administered in the total of 53 cases (5.1% from the whole amount of coronary angioplasties), in 30 cases (15.4% from the total of 195 patients) of the primary coronary angioplasties, unlike the elective procedures, where these agents were given only in 9 patients (1.5% from the overall number of 621 coronary angioplasties) (p < 0.001). The authors in their work analyse the group of patients treated with primary coronary angioplasty with adjuvant treatment of IIb/IIIa platelet blockers. RESULTS: In the stated period the IIb/IIIa platelet blockers were given to 30 patients at the age of 60.3 +/- 11.3 on average (70% were men). The most frequent risk factors were smoking, in 18 patients (60%), and hypertension, in 14 patients (40%). At least one coronary stent was implanted in 20 patients (66.7%). Abciximab was administered in 27 cases (90%) and eptifibatid in 5 cases (10%). Solely in 5 cases (16.7%) the agents were administered at least 10 minutes before the intervention and therefore preventively, and in 25 cases (83.3%) the administration was rescue. The reason for preventive administration was in 3 cases determination of the angiographically high-risk coronary artery disease and in 2 cases the thrombosis of another non-infarction related artery. The most frequent reason for the rescue use was in 6 cases (22.2%) slow-flow or no-reflow fenomena even after the mechanical obstacles and in 5 cases (18.5%) that were successfully treated with further dilatation, the acute in-stent thrombosis was observed. The infarct-related artery was most often the left anterior descending coronary artery, namely in 16 cases (54%). CONCLUSION: IIb/IIIa platelet blockers in primary coronary angioplasty administered either preventively or as rescue therapy are highly effective, relatively safe and improve the effectiveness of mechanical reperfusion. The total in-hospital mortality of this group of patients was 10%.

[ST-segment resolution as a simple tool for the assessment of successful primary coronary intervention at a microvascular level]. / Ustup ST elevací jako jednoduchý nástroj pro posouzení úspesnosti primární koronární intervence na mikrovaskuláirní úrovni.

BACKGROUND: The primary success of the coronary artery reperfusion by primary coronary intervention (PCI) is almost angiographically assessed by TIMI flow score. The perfusion at a microvascular level can be inadequate despite the restoring of normal flow in the epicardial coronary artery. One of the options of successful reperfusion at a microvascular level is the measurement of ST-segment resolution (STR) after primary PCI. AIM: The assessment of ST-segment resolution in patients indicated for primary PCI and the comparison with clinical data. METHODS: The authors studied 149 patients (68.5 % men) with ST elevation acute myocardial infarction treated by primary PCI. The ECG was taken at the time of arriving patient at coronary unit and compared with ECG early after primary PCI. Patients were divided into 3 groups according to the grade of STR: with complete (> or = 70%), partial (30-69%) and none (< 30%) STR. The lead with maximal changes (STEmax) and sum of ST elevation (STEsum) were assessed. RESULTS: 42 (28.2 %) patients had complete STR, 55 (36.9%) partial STR and 52 (34.9%) patients didn't achieve STR. STR was connected with better left ventricular ejection fraction, which was in group with complete STR 50% compared with 39.4% in group without STR (p < 0.0001). Patients with symptoms of heart failure on admission (Killip II-IV) had complete STR only in 4 cases (10%) compared with patients without heart failure (Killip I), where was complete STR in 38 (34.8%), (p = 0.003). There wasn't noted significant difference in STR at dependence on glycoprotein IIb/IIIa inhibitors administration. A normal or mildly slower coronary flow (TIMI 2, 3) was achieved in 146 patients (98%), 3 patients (2%) had inadequate coronary flow after primary PCI (TIMI 0, 1). CONCLUSIONS: The evaluation of early ECG changes is simple method for the assessment of primary PCI success at the microvascular level. Our outcomes confirm a differences in achievement of optimal epicardial coronary flow and a perfusion at microvascular level.

Relationship between high aortic pulse pressure and extension of coronary atherosclerosis in males.

A high pulse pressure (PP) is a marker of increased artery stiffness and represents a well-established independent predictor for cardiovascular morbidity and mortality. The objective of the research was to determine whether invasively measured central aortic PP was related to the presence and severity of coronary artery disease. In total 1075 consecutive stable male patients undergoing diagnostic coronary angiography with a preserved left ventricular function were included. Diseased coronary vessel (DCV) was defined by the presence of >50 % stenosis. Men were divided into 3 groups according to the increased value of PP. The average PP in the tertiles was 47.8+/-7.1 vs. 67.0+/-4.9 vs. 91.3+/-12.8 mm Hg (p<0.01). The significant differences of DCV was found among tertiles (1.51+/-1.11 vs 1.80+/-1.04 vs. 1.99+/-0.98 DCV, p<0.01). Aortic PP together with age and hyperlipoproteinemia were found as factors with an independent relationship to DCV according to multivariate linear regression. In conclusions the increased value of aortic PP in the male population is independently connected with more severe atherosclerosis evaluated by the significant number of DCV.

How perfect can graphene be?

We have identified the cyclotron resonance response of the purest graphene ever investigated, which can be found in nature on the surface of bulk graphite, in the form of decoupled layers from the substrate material. Probing such flakes with Landau level spectroscopy in the THz range at very low magnetic fields, we demonstrate a superior electronic quality of these ultralow density layers (n_{0} approximately 3 x 10;{9} cm;{-2}) expressed by the carrier mobility in excess of 10;{7} cm;{2}/(V * s) or scattering time of tau approximately 20 ps. These parameters set new and surprisingly high limits for intrinsic properties of graphene and represent an important challenge for further developments of current graphene technologies.

[The influence of different alpha-sympathomimetic drugs and benzalkoniumchlorid on the ciliary beat frequency of in vitro cultured human nasal mucosa cells]. / Der Einfluss verschiedener alpha-Sympathomimetika und Benzalkoniumchlorid auf die Zilienschlagfrequenz humaner Flimmerzellen in vitro.

BACKGROUND: An appropriate in-vitro model of the human nasal mucosa was developed, which allowed to measure the influence of different pharmaceutical substances on the ciliary beat frequency (CBF) under standardized conditions. METHOD: The present study describes the effect of the alpha-sympathomimetic drugs naphazolin, xylometazolin and oxymetazolin as pure substances and the preservative Benzalkonium chloride in rising concentrations on the CBF. For these investigations human cells of the human nasal mucosa were cultured, which exhibited a high constancy during the equilibration measurements over at least 200 minutes. RESULTS: The alpha-sympathomimetic drugs oxymetazoline in the concentration of 0.01% and 0.001% as well as naphazoline within all three concentrations did not show any change of the CBF. Whereas xylometazoline in the concentration of 0.1% caused a high-significant decrease of the CBF. This decrease of the CBF was however partially reversible after rinsing out. Oxymetazolin showed likewise a significant decrease of the CBF in the concentration of 0.1%. This effect however was not reversible after rinsing out with substrate-free medium, but on the contrary showed up a further decrease of CBF. The preservative benzalkonium chloride effected an irreversible ciliostatic activity already in the concentration of 0.005%. CONCLUSIONS: From the three investigated alpha-sympathomimetic drugs only naphazoline in all measured concentrations did not show any toxic effect. With regard to its therapeutic application this drug in the concentrations 0.001%-0.1% should be preferred to all other alpha-sympathomimetic drugs. Oxymetazoline in the concentration of 0.01% and 0.001% had no toxic effect as well. It however caused an irreversible damage to the cilia in the concentration of 0.1%. This should be considered for the application of rhinological drugs especially in children. The same attention is demanded for xylometazoline, causing a high significant release of CBF in the concentration of 0.1%, which is only partially reversible. Due to the results of this study it has strongly to be advised against the use of all rhinological drugs containing the preservative benzalkonium chloride.

Approaching the dirac point in high-mobility multilayer epitaxial graphene.

Multilayer epitaxial graphene is investigated using far infrared transmission experiments in the different limits of low magnetic fields and high temperatures. The cyclotron-resonance-like absorption is observed at low temperature in magnetic fields below 50 mT, probing the nearest vicinity of the Dirac point. The carrier mobility is found to exceed 250,000 cm2/(V x s). In the limit of high temperatures, the well-defined Landau level quantization is observed up to room temperature at magnetic fields below 1 T, a phenomenon unusual in solid state systems. A negligible increase in the width of the cyclotron resonance lines with increasing temperature indicates that no important scattering mechanism is thermally activated.