On the theory of deuteron NMR free induction decay of reptating polymer chains: Effect of end segment dynamics.

A self-consistent approximation beyond the Redfield limit and without using the Anderson-Weiss approximation for the Free Induction Decay (FID) of deuteron spins belonging to polymer chains undergoing reptation is formulated. The dynamical heterogeneity of the polymer segments created by the end segments is taken into account. Within an accuracy of slow-changing logarithmic factors, FID can be qualitatively described by a transition from an initial pseudo-Gaussian to a stretched-exponential decay at long times. With an increase in observation time, the contribution from end effects to the FID increases. In the regime of incoherent reptation, contributions to the FID from central segments yield an exponent of 1/4 for the stretched decay and contributions from end segments yield an exponent of 3/16. In the regime of coherent reptation, the central segments generate a stretching exponent of 1/2, whereas the end segments contribute with an exponent of 1/4. These predictions are shown to be in qualitative agreement with the experimental FIDs of perdeuterated poly(ethylene oxide) with molecular masses of 132 kg/mol and 862 kg/mol.

Perspectives of Deuteron Field-Cycling NMR Relaxometry for Probing Molecular Dynamics in Soft Matter.

Due to the single-particle character of the quadrupolar interaction in molecular systems, (2)H NMR poses a unique method for probing reorientational dynamics. Spin-lattice relaxation gives access to the spectral density, and its frequency dependency can be monitored by field-cycling (FC) techniques. However, most FC NMR studies employ (1)H; the use of (2)H is still rare. We report on the application of (2)H FC NMR for investigating the dynamics in molecular liquids and polymers. Commercial as well as home-built relaxometers are employed accessing a frequency range from 30 Hz to 6 MHz. Due to low gyromagnetic ratio, high coupling constants, and finite FC switching times, current (2)H FC NMR does not reach the dispersion region in liquids (toluene and glycerol), yet good agreement with the results from conventional high-field (HF) relaxation studies is demonstrated. The pronounced difference at low frequencies between (2)H and (1)H FC NMR data shows the relevance of intermolecular relaxation in the case of (1)H NMR. In the case of the polymers polybutadiene and poly(ethylene-alt-propylene), very similar relaxation dispersion is observed and attributed to Rouse and entanglement dynamics. Combination with HF (2)H relaxation data via applying frequency-temperature superposition allows the reconstruction of the full spectral density reflecting both polymer as well as glassy dynamics. Transformation into the time domain yields the reorientational correlation function C2(t) extending over nine decades in time with a long-time power law, C2(t) ∝ t(-0.45±0.05), which does not conform to the prediction of the tube-reptation model, for which ∝ t(-0.25) is expected. Entanglement sets in below C2(t = τe) ≅ S(2) = 0.001, where τe is the entanglement time and S the corresponding order parameter. Finally, we discuss the future prospects of the (2)H FC NMR technique.

Dynamics of asymmetric binary glass formers. II. Results from nuclear magnetic resonance spectroscopy.

Various (2)H and (31)P nuclear magnetic resonance (NMR) spectroscopy techniques are applied to probe the component dynamics of the binary glass former tripropyl phosphate (TPP)/polystyrene-d3 (PS) over the full concentration range. The results are quantitatively compared to those of a dielectric spectroscopy (DS) study on the same system previously published [R. Kahlau, D. Bock, B. Schmidtke, and E. A. Rössler, J. Chem. Phys. 140, 044509 (2014)]. While the PS dynamics does not significantly change in the mixtures compared to that of neat PS, two fractions of TPP molecules are identified, one joining the glass transition of PS in the mixture (α1-process), the second reorienting isotropically (α2-process) even in the rigid matrix of PS, although at low concentration resembling a secondary process regarding its manifestation in the DS spectra. Pronounced dynamical heterogeneities are found for the TPP α2-process, showing up in extremely stretched, quasi-logarithmic stimulated echo decays. While the time window of NMR is insufficient for recording the full correlation functions, DS results, covering a larger dynamical range, provide a satisfactory interpolation of the NMR data. Two-dimensional (31)P NMR spectra prove exchange within the broadly distributed α2-process. As demonstrated by (2)H NMR, the PS matrix reflects the faster α2-process of TPP by performing a spatially highly hindered motion on the same timescale.

Cardiac manifestation of the hypereosinophilic syndrome: new insights.

Cardiac manifestation is the major cause of morbidity in patients with hypereosinophilic syndrome (HES). Clinical features range from heart failure to arterial embolism, which are caused by thickening of the endocardium and mural left ventricular thrombosis. Modern magnetic resonance imaging and echocardiography are able to detect fibrosis, eosinophilic infiltrate and thrombi to stage the fibrotic evolution of the disease. Treatment of HES involves standard medication for heart failure, anticoagulant therapy, immunosuppressive therapy and potentially surgical resection. The outcome of HES depends on both the progression of endocardial fibrosis and associated complications and the 5-year mortality is estimated at 30%.

[CRT in atrial fibrillation--methodical and apparatus options in decision-making]. / CRT bei Vorhofflimmern. Methodische und apparative Optionen zur Entscheidungsfindung.

Heart failure and atrial fibrillation often coexist, especially with increasing degree of heart failure severity. Under this constellation, the advantage of cardiac resynchronization therapy (CRT) is still under discussion and displayed as an unresolved problem in the guidelines for cardiac stimulation and resynchronization. If ventricular desynchronization can be documented and response to CRT can be expected, the challenge is to interoperatively seek the best left ventricular electrode position and to postoperatively optimize the device in order to achieve the best therapy performance. This situation encourages the development of individualized methods and to utilize innovative apparatus features in order to consolidate individual decisions and to optimize CRT in heart failure with atrial fibrillation.

[The "broken heart" syndrome--a rare clinical phenomenon]. / Das "Broken Heart"-Syndrom--Ein seltenes klinisches Phänomen.

BACKGROUND AND OBJECTIVE: A clinical entity that mimics acute coronary syndrome with reversible left ventricular systolic dysfunction and is triggered by emotional stress was identified in 6 patients by screening a database of > 1000 patients with the ICD-10 coding of acute coronary syndrome. The search criteria were acute coronary syndrome, normal coronary anatomy, absence of coronary lesions and transient left ventricular dysfunction, triggered by emotional stress. PATIENTS AND METHODS: We analyzed 6 patients, who fulfilled the criteria of (1) acute substernal chest pain with ST-segment elevation and/or T-wave inversion; (2) absence of significant coronary arterial narrowing on angiography, (3) systolic dysfunction with abnormal regional wall motion ("apical ballooning") in the context of (4) severe psychological stress immediately before and triggering the cardiac events. RESULTS: The primary diagnosis for all 6 acutely ill patients accorded with the ICD-code of acute coronary syndrome. All patients had survived and eventually recovered with an LV ejection fraction of 60 +/- 5 %; P = 0.03 and had had recovered normal levels of physical activity at hospital discharge. Of note is the number of women of postmenopausal age. CONCLUSIONS: A transient cardiomyopathy triggered by major emotional stress may mimic an acute coronary syndrome but without significant coronary artery disease. This condition is characterized by reversible cardiac dysfunction and may be more frequent in women. It has a favorable clinical outcome.

Process tomography of ion trap quantum gates.

A crucial building block for quantum information processing with trapped ions is a controlled-NOT quantum gate. In this Letter, two different sequences of laser pulses implementing such a gate operation are analyzed using quantum process tomography. Fidelities of up to 92.6(6)% are achieved for single-gate operations and up to 83.4(8)% for two concatenated gate operations. By process tomography we assess the performance of the gates for different experimental realizations and demonstrate the advantage of amplitude-shaped laser pulses over simple square pulses. We also investigate whether the performance of concatenated gates can be inferred from the analysis of the single gates.

[Dual antithrombotic therapy after implantation of coronary stents]. / Duale antiaggregatorische Therapie nach Implantation von Koronarstents.

Dual antiplatelet-aggregation treatment with aspirin and clopidogrel after coronary stent implantation is nowadays standard peri-interventional practice, although its use is not yet licensed for this indication in many European countries. Clopidogrel administration is initiated before PCI with a loading dose of 300 mg when given at least 6 hours before PCI, otherwise 600 mg. The required duration of combined (aspirin + clopidogrel) antiplatelet-aggregation treatment after coronary stent implantation depends on the type of stent and the pre-existing disease. After bare-metal stent implantation dual antiplatelet medication is needed for at least 3-4 weeks, after drug-eluting stent implantation 6 months, after coronary brachytherapy 12 months, and 9 months after an acute coronary syndrome. These time intervals should also be respected before any elective surgical intervention. Early operations, because postponement is impossible, should be performed under antiplatelet-aggregation treatment after assessment of bleeding risk in the individual case. Premature termination of this treatment carries an increased risk of serious cardiovascular events, especially stent thrombosis and myocardial infarction. Prolonged antiplatelet-aggregation treatment is of benefit especially in patients with a high risk of serious cardiovascular events. Patients with an indication for long-term anticoagulation may require, during the period of highest risk of stent thrombosis after stent implantation, administration of combined aspirin, clopidogrel and anticoagulants with an INR target value in the lower therapeutic range. The increased risk of bleeding must be weighed up against the potential benefit.

[Left ventricular electromechanical latency period is an additional indicator to upgrade from right to biventricular DDD pacing]. / Die linksventrikuläre elektromechanische Latenzzeit ist ein zusätzlicher Indikator für ein Upgrading zur biventrikulären Stimulation.

In DDD pacing, the left-ventricular electromechanical latency period defines the duration between premature ventricular stimulation and the prematurely ending left-atrial contribution to left-ventricular filling. It has to be considered in diastolic AV delay optimization. Individual duration of this parameter seemed to reflect the ventricular function. Therefore, we compared the left-ventricular electromechanical latency period due to right ventricular stimulus with the documented ejection fraction of two groups, 33 congestive heart failure patients carrying biventricular systems and 13 right ventricular paced bradycardia patients. A mean latency period of 168+/-26 ms was found in the heart failure patients (ejection fraction: 25+/-5%) which was significantly longer (p=0.0039) compared to the bradycardia patients (ejection fraction: 51+/-12%) with a mean latency of 119+/-13 ms. Thus, an increasing latency period during right ventricular DDD pacing therapy indicates decreasing ejection fraction. A cut-off interval of 135 ms allowed the discrimination of 93% of our patients as having an individual ejection fraction of either up to 35% or above. Thus, the left ventricular electromechanical latency period can be used as an additional parameter indicating the necessity to upgrade from right to biventricular DDD pacing.

[Feasibility and safety of long-term AAI(R) pacing in isolated sinus node syndrome]. / Realisierbarkeit und Sicherheit einer alleinigen AAI(R)-Schrittmacherbehandlung beim isolierten symptomatischen Sinusknotensyndrom.

Recent investigations prove that AAI(R) pacing is the "ideal" stimulation mode in isolated sick sinus syndrome. Nevertheless, in Germany this bradycardia is treated by AAI(R) pacemakers in less than 4% of cases compared to 25% in other countries. In our institution treatment of patients with isolated sick sinus syndrome is uniform and corresponds to the actual guidelines since the early 1990s; therefore the aim of our study was to analyze feasibility and safety of AAI(R) pacing in a retrospective study. Between 1998 and 2000, 52 of 165 patients (31.5%) with isolated sick sinus syndrome were treated by an AAI(R) pacemaker. The median follow-up duration was 51.5 months (minimal: 36 months). 6 patients died, in all cases unrelated to the stimulation mode. Three patients required reoperations, however, in only one case due to second degree AV block with the need for upgrading to DDD stimulation. Thus, the yearly incidence of this specific complication in the AAI(R) cohort is 0.64%.In conclusion, permanent atrial stimulation in isolated sick sinus syndrome is feasible in a quarter of all cases. It is safe if performed corresponding to actual guidelines. Additionally, single lead AAI(R) pacing is a cost-effective therapy and the only stimulation mode which, today, reliably prevents unnecessary right ventricular stimulation. If, on the other hand, algorithms providing automatic mode switching from AAI to DDD and vice versa are implemented reliably into all dual chamber pacemakers, single chamber atrial pacing will no longer be a subject for discussion.

Scalable multiparticle entanglement of trapped ions.

The generation, manipulation and fundamental understanding of entanglement lies at the very heart of quantum mechanics. Entangled particles are non-interacting but are described by a common wavefunction; consequently, individual particles are not independent of each other and their quantum properties are inextricably interwoven. The intriguing features of entanglement become particularly evident if the particles can be individually controlled and physically separated. However, both the experimental realization and characterization of entanglement become exceedingly difficult for systems with many particles. The main difficulty is to manipulate and detect the quantum state of individual particles as well as to control the interaction between them. So far, entanglement of four ions or five photons has been demonstrated experimentally. The creation of scalable multiparticle entanglement demands a non-exponential scaling of resources with particle number. Among the various kinds of entangled states, the 'W state' plays an important role as its entanglement is maximally persistent and robust even under particle loss. Such states are central as a resource in quantum information processing and multiparty quantum communication. Here we report the scalable and deterministic generation of four-, five-, six-, seven- and eight-particle entangled states of the W type with trapped ions. We obtain the maximum possible information on these states by performing full characterization via state tomography, using individual control and detection of the ions. A detailed analysis proves that the entanglement is genuine. The availability of such multiparticle entangled states, together with full information in the form of their density matrices, creates a test-bed for theoretical studies of multiparticle entanglement. Independently, 'Greenberger-Horne-Zeilinger' entangled states with up to six ions have been created and analysed in Boulder.

Deterministic quantum teleportation with atoms.

Teleportation of a quantum state encompasses the complete transfer of information from one particle to another. The complete specification of the quantum state of a system generally requires an infinite amount of information, even for simple two-level systems (qubits). Moreover, the principles of quantum mechanics dictate that any measurement on a system immediately alters its state, while yielding at most one bit of information. The transfer of a state from one system to another (by performing measurements on the first and operations on the second) might therefore appear impossible. However, it has been shown that the entangling properties of quantum mechanics, in combination with classical communication, allow quantum-state teleportation to be performed. Teleportation using pairs of entangled photons has been demonstrated, but such techniques are probabilistic, requiring post-selection of measured photons. Here, we report deterministic quantum-state teleportation between a pair of trapped calcium ions. Following closely the original proposal, we create a highly entangled pair of ions and perform a complete Bell-state measurement involving one ion from this pair and a third source ion. State reconstruction conditioned on this measurement is then performed on the other half of the entangled pair. The measured fidelity is 75%, demonstrating unequivocally the quantum nature of the process.

[Percutaneous stents for the treatment of stenosis of descending aorta]. / Perkutane Stents zur Behandlung stenosierender Prozesse der deszendierenden Aorta.

Stenotic processes of the descending aorta lead to a transstenotic gradient with either risk of proximal hypertension especially affecting the cerebral circulation combined with the risk of distal malperfusion. This article describes the technique of percutaneous stenting of suprarenal aortic stenosis in two patients with different genesis of aortic obstruction in whom operative correction was refused due to elevated surgical risk. The first patient (female, 38 years) suffered from aortic stenosis at the thoracoabdominal level revealing a residual lumen of 3 mm. The second patient (male, 71 years) had a chronic type B aortic dissection and developed dynamic compression of true lumen and thus peripheral malperfusion. Both patients were treated successfully with percutaneous implantation of self-expanding stents. During the follow-up of 6 and 10 months, respectively, both patients were free of any symptoms. The technique of percutaneous stenting of static and dynamic stenotic processes of the aorta led to excellent mid-term results. Long-term results of large patient cohorts are not available yet; however, all patients subjected to such a palliative procedure should be followed in structured registries in an effort to standardize the concept and develop therapeutic recommendations.

[Acute thrombosis of pelvic and leg veins in agenesis of the renal segment of the inferior vena cava]. / Akute Becken-Beinvenenthrombose bei Agenesie des renalen Segments der Vena cava inferior.

A 19-year-old, otherwise asymptomatic man presented to the hospital of orthopaedic surgery with acute severe pain like lumbago. Symptomatic treatment was performed after extensive orthopaedic diagnostic procedures. On the third day after admission he showed clinical signs of deep vein thrombosis with painful swelling and livid discoloration of both legs. Colour duplex ultrasound revealed complete thrombosis of the leg and pelvic veins bilaterally, but the cranial extent was not clear. Contrast-enhanced helical computer tomography of the abdomen and the pelvis confirmed deep pelvic vein thrombosis and showed extension into the inferior vena cava. Moreover, the study revealed the agenesis of the renal segment of the inferior vena cava with collateral flow through dilated lumbar veins to enlarged azygous and hemiazygous, through vertebral and paravertebral venous plexus. The renals were drained via dilated capsular veins. The agenesis of renal vena cava is a very rare anomaly causing acute thrombosis of the deep leg and pelvic veins. Other risk factors of thromboembolic disease were not found. The patient was treated successfully with systemic thrombolysis. Therefore we used ultra-high streptokinase infusion (9 million units over 6 hours). Colour duplex ultrasound revealed good flow into deep leg and pelvic veins after three cycle of lysis. Magnetic resonance angiography of the abdomen and pelvis was performed to evaluate the successful fibrinolysis with complete recanalisation of the pelvic veins and to demonstrate the venous anatomy. Permanent oral anticoagulation with phenprocoumon is indicated to decrease the high rate of recurrent thrombosis. Compression stockings were prescribed. To prevent thrombosis, additional risk factors like smoking, immobilization and unusual physical activity should be strictly avoided.

[Perforated mitral valve aneurysm as a rare course of bacterial endocarditis]. / Perforiertes Mitralklappenaneurysma als seltene Verlaufsform einer bakteriellen Endokarditis.

A 65 year old man with a history of mechanical aortic valve replacement acquired Enterococcus faecalis mediated infective endocarditis about 3 years later. Transesophageal echocardiography revealed formation of an aneurysm confined to the anterior mitral valve leaflet. The aortic valve revealed no signs of endocarditis by transesophageal ultrasound. With sudden perforation of the mitral valve aneurysm, subsequent hemodynamic deterioration and pulmonary oedema, the patient underwent emergency mitral and aortic valve replacement. The postoperative course was uneventful.

Digital nasotracheal intubation.

Digital nasotracheal intubation may be useful in situations where blind nasotracheal intubation is unsuccessful. This technique can be performed in edentulous patients and may prove to be a valuable adjunct in controlling the airway.

Blast injuries from glass bottles containing dry ice.

We present three cases (two incidents) of severe blast injury from the explosion of covered glass bottles containing dry ice. The first patient sustained lacerations of the face, left eye, right wrist and forearm, and abdomen with protrusion of the small bowel. The second sustained a deep laceration to her anterior neck. The third sustained multiple lacerations to her lower extremities and one to the labia majora. All three patients were taken to the operating room for surgical exploration and repair and were discharged without complications.