PubMed Health⌕ Search

Biomedical subjects

M Kindermann

Publications and source records attributed to M Kindermann.

At least 19 recordsLinked to original sources
PubMed2006

[Invasive diagnosis of pulmonary hypertension and its effects on the right heart].

When pulmonary hypertension (HPT) is suspected invasive diagnosis provides final diagnosis, establishes the most important parameters for making a prognosis and identifies resulting abnormalities of the right and left ventricles. Cardiac catheterization gives data on cardiac function and thus additional information on the limits of physical capacity and prognostic assessment. Invasive diagnosis thus plays a key role, but clearly is not part of primary diagnosis, which in addition to clinical examination emphasizes Doppler echocardiography as a valid screening method. Noninvasive examinations are preferred for follow-up.

Catheterization, Swan-Ganz↗
PubMed2006

Interference as a probe of spin incoherence in strongly interacting quantum wires.

We show that interference experiments can be used to identify the spin-incoherent regime of strongly interacting one-dimensional conductors. Two qualitative signatures of spin incoherence are found: a strong magnetic field dependence of the interference contrast and an anomalous scaling of the interference contrast with the applied voltage, with a temperature and magnetic field dependent scaling exponent. The experiments distinguish the spin-incoherent from the spin-polarized regime, and so may be useful in deciding between alternative explanations proposed for the anomalous conductance quantization observed in quantum point contacts and quantum wires at low density.

Journal Article↗
PubMed2006

Proposal of an experimentally accessible measure of many-fermion entanglement.

We propose an experimentally accessible measure of entanglement in many-fermion systems that characterizes interaction-induced ground state correlations. It is formulated in terms of cross correlations of currents through resonant fermion levels weakly coupled to the probed system. The proposed entanglement measure vanishes in the absence of many-body interactions at zero temperature and it is related to measures of occupation number entanglement. We evaluate it for two examples of interacting electronic nanostructures.

Journal Article↗
PubMed2006

[Drug treatment of chronic heart failure].

Drug treatment of chronic heart failure is undergoing continuous modifications according to the data of new trials. Treatment has to be adjusted to current guidelines. The state of the art of medical treatment of chronic heart failure is addressed in this report.

Adrenergic beta-Antagonists↗
PubMed2005

Frequency-dependent transport through a quantum dot in the Kondo regime.

We study the ac conductance and equilibrium current fluctuations of a Coulomb-blockaded quantum dot in the Kondo regime. To this end we have developed an extension of the numerical renormalization group suitable for the nonperturbative calculation of finite-frequency transport properties. We demonstrate that ac transport gives access to the many-body resonance in the equilibrium spectral density. It provides a new route for measuring this key signature of Kondo physics, which so far has defied direct experimental observation.

Journal Article↗
PubMed2005

Splenic rupture complicating periinterventional glycoprotein IIb/IIIa antagonist therapy for myocardial infarction in polycythemia vera.

Polycythemia vera is a myeloproliferative disorder predisposing to thromboembolic and bleeding complications. We report the case of a patient with polyglobuly, leukocytosis, and thrombocytosis, who suffered from acute ST-segment elevation myocardial infarction due to thrombotic high-grade pre-stent stenosis two months after percutaneous coronary intervention for complex coronary one vessel disease. Following re-PTCA and stent implantation in conjunction with periinterventional GP IIb/IIIa antagonist treatment, the patient was initially symptom free for about two hours before rapidly developing signs of a hemorrhagic shock. An abdominal CT scan showed splenic rupture with massive intraabdominal hemorrhage as a consequence of secondary bleeding into multiple pre-existing splenic infarctions. The patient's condition stabilized after emergency splenectomy. Subsequent bone marrow biopsy revealed the presence of polycythemia vera. Post-operatively, the patient was treated with the anti-platelet agents aspirin and clopidogrel to prevent subacute stent thrombosis. Additionally, cyto-reductive therapy with hydroxyurea was initiated because of a further increase in the platelet count. In patients with polycythemia vera, the indication for treatment with GP IIb/IIIa antagonists should be carefully weighed against the potentially serious bleeding complications. Should treatment be established, a risk stratification using abdominal sonography and bleeding time testing is recommended, while during treatment red blood count, platelet count, coagulation tests, and hemodynamic parameters should be closely monitored.

Abciximab↗
PubMed2004

Charge detection enables free-electron quantum computation.

It is known that a quantum computer operating on electron-spin qubits with single-electron Hamiltonians and assisted by single-spin measurements can be simulated efficiently on a classical computer. We show that the exponential speedup of quantum algorithms is restored if single-charge measurements are added. These enable the construction of a CNOT (controlled NOT) gate for free fermions, using only beam splitters and spin rotations. The gate is nearly deterministic if the charge detector counts the number of electrons in a mode, and fully deterministic if it only measures the parity of that number.

Journal Article↗
PubMed2004

Quantum teleportation by particle-hole annihilation in the Fermi sea.

We point out that the mutual annihilation of an electron-hole pair at a tunnel barrier leads to teleportation of the state of the annihilated electron to a second, distant electron--if the latter was previously entangled with the annihilated hole. We propose an experiment, involving low-frequency noise measurements on a two-dimensional electron gas in a high magnetic field, to detect teleportation of electrons and holes in the two lowest Landau levels.

Journal Article↗
PubMed2004

[Heart disease in schizophrenia].

A 63-year-old male patient diagnosed with chronic schizophrenia and characterized by formal disorders of thought with neologism and paranoid ideation, especially grandiose delusions and feelings of being influenced by radiation, is presented. At admission to psychiatric hospital, the patient reported attacks of weakness and dizziness, which he attributed to his feelings of alien influence. The diagnosis of cardiac disease with severe bradycardia could already be established by basic physical examination. Further diagnostic procedures (e.g., ECG) revealed symptomatic atrioventricular conduction defects (atrioventricular block III). After implantation of a cardiac pacemaker, the somatic symptoms vanished and the patient recovered completely in terms of physical condition.

Bradycardia↗
PubMed2003

Proposal for production and detection of entangled electron-hole pairs in a degenerate electron gas.

We demonstrate theoretically that the shot noise produced by a tunnel barrier in a two-channel conductor violates a Bell inequality. The nonlocality is shown to originate from entangled electron-hole pairs created by tunneling events-without requiring electron-electron interactions. The degree of entanglement (concurrence) equals 2(T1T2)(1/2)(T1+T2)(-1), with T1,T2<<1 the transmission eigenvalues. A pair of edge channels in the quantum Hall effect is proposed as an experimental realization.

Journal Article↗
PubMed2003

Interaction effects on counting statistics and the transmission distribution.

We investigate the effect of weak interactions on the full counting statistics of charge transfer through an arbitrary mesoscopic conductor. We show that the main effect can be incorporated into an energy dependence of the transmission eigenvalues and study this dependence in a nonperturbative approach. An unexpected result is that all mesoscopic conductors behave at low energies such as either a single or a double tunnel junction, which divides them into two broad classes.

Journal Article↗
PubMed2003

Distribution of voltage fluctuations in a current-biased conductor.

We calculate the fluctuating voltage V(t) over a conductor driven out of equilibrium by a current source. This is the dual of the shot noise problem of current fluctuations I(t) in a voltage-biased circuit. In the single-channel case the distribution of the accumulated phase Phi=(e/ variant Planck's over 2pi ) integral Vdt is the Pascal (or binomial waiting-time) distribution-distinct from the binomial distribution of transferred charge Q= integral Idt. The weak-coupling limit of a Poissonian P(Phi) is reached in the limit of a ballistic conductor, while in the tunneling limit P(Phi) has the chi-square form.

Journal Article↗
PubMed2003

Temperature-dependent third cumulant of tunneling noise.

Poisson statistics predicts that the shot noise in a tunnel junction has a temperature independent third cumulant e(2)I, determined solely by the mean current I. Experimental data, however, show a puzzling temperature dependence. We demonstrate theoretically that the third cumulant becomes strongly temperature dependent and may even change sign as a result of feedback from the electromagnetic environment. In the limit of a noninvasive (zero-impedance) measurement circuit in thermal equilibrium with the junction, we find that the third cumulant crosses over from e(2)I at low temperatures to -e(2)I at high temperatures.

Journal Article↗
PubMed2003

[Detection of left ventricular ischemia at rest by tissue Doppler echocardiography].

UNLABELLED: A 53-year old woman without a previous history of cardiac disease was successfully resuscitated from ventricular fibrillation. Despite a normal two dimensional echocardiogram, tissue Doppler analysis of left ventricular long-axis contraction revealed marked postsystolic contractions in the territory of the left coronary artery suggesting ischemia as the underlying pathogenetic mechanism. This was confirmed by coronary angiography which revealed a high-grade ostial stenosis of the left main stem. After coronary artery bypass surgery, the tissue Doppler findings normalized. CONCLUSION: Assessment of regional long axis function by tissue Doppler echocardiography may yield important additional findings even if two-dimensional echocardiography is apparently normal.

Coronary Angiography↗