Light-induced cross-linking and post-cross-linking modification of polyglycidol.

The photoinduced radical generation process has received renewed interest due to its economic and ecological appeal. Herein the light-induced cross-linking of functional polyglycidol and its post-cross-linking modification are presented. Linear polyglycidol was first functionalized with a tertiary amine in a two-step reaction. Dimethylaminopropyl functional polyglycidol was cross-linked in a UV-light mediated reaction with camphorquinone as a type II photoinitiator. The cross-linked polyglycidol was further functionalized by quaternization with various organoiodine compounds. Aqueous dispersions of the cross-linked polymers were investigated by means of DLS and zeta potential measurements. Polymer films were evaluated by DSC and XPS.

Quantum Nondemolition Measurement of a Quantum Squeezed State Beyond the 3 dB Limit.

We use a reservoir engineering technique based on two-tone driving to generate and stabilize a quantum squeezed state of a micron-scale mechanical oscillator in a microwave optomechanical system. Using an independent backaction-evading measurement to directly quantify the squeezing, we observe 4.7±0.9 dB of squeezing below the zero-point level surpassing the 3 dB limit of standard parametric squeezing techniques. Our measurements also reveal evidence for an additional mechanical parametric effect. The interplay between this effect and the optomechanical interaction enhances the amount of squeezing obtained in the experiment.

Intracavity Squeezing Can Enhance Quantum-Limited Optomechanical Position Detection through Deamplification.

It has been predicted and experimentally demonstrated that by injecting squeezed light into an optomechanical device, it is possible to enhance the precision of a position measurement. Here, we present a fundamentally different approach where the squeezing is created directly inside the cavity by a nonlinear medium. Counterintuitively, the enhancement of the signal-to-noise ratio works by deamplifying precisely the quadrature that is sensitive to the mechanical motion without losing quantum information. This enhancement works for systems with a weak optomechanical coupling and/or strong mechanical damping. This can allow for larger mechanical bandwidth of quantum-limited detectors based on optomechanical devices. Our approach can be straightforwardly extended to quantum nondemolition qubit detection.

QUANTUM MECHANICS. Quantum squeezing of motion in a mechanical resonator.

According to quantum mechanics, a harmonic oscillator can never be completely at rest. Even in the ground state, its position will always have fluctuations, called the zero-point motion. Although the zero-point fluctuations are unavoidable, they can be manipulated. Using microwave frequency radiation pressure, we have manipulated the thermal fluctuations of a micrometer-scale mechanical resonator to produce a stationary quadrature-squeezed state with a minimum variance of 0.80 times that of the ground state. We also performed phase-sensitive, back-action evading measurements of a thermal state squeezed to 1.09 times the zero-point level. Our results are relevant to the quantum engineering of states of matter at large length scales, the study of decoherence of large quantum systems, and for the realization of ultrasensitive sensing of force and motion.

[MR-guided interventions of the prostate gland: a literature review]. / Aktueller Stand der MR-gesteuerten Prostata-Interventionen.

In recent years MR imaging has played an increasingly important role in the diagnosis and treatment of prostate cancer. MR imaging of the prostate allows clear delineation of the anatomic structures and prostate tumors using T 2-weighted images combined with spectroscopy and dynamic examinations. The advantages of MRI make it possible to perform interventions, like biopsies, brachytherapy or different local therapies of the prostate gland. MRI robotic assistance will improve the accuracy of the interventions. Due to the advantages of MR imaging, MR-guided prostate interventions will play a greater role in the future.

Strong coupling of a mechanical oscillator and a single atom.

We propose and analyze a setup to achieve strong coupling between a single trapped atom and a mechanical oscillator. The interaction between the motion of the atom and the mechanical oscillator is mediated by a quantized light field in a laser driven high-finesse cavity. In particular, we show that high fidelity transfer of quantum states between the atom and the mechanical oscillator is in reach for existing or near future experimental parameters. Our setup provides the basic toolbox from atomic physics for coherent manipulation, preparation, and measurement of micromechanical and nanomechanical oscillators.

Correlation-induced resonances in transport through coupled quantum dots.

We investigate the effect of local electron correlations on transport through parallel quantum dots. The linear conductance as a function of gate voltage is strongly affected by the interplay of the interaction U and quantum interference. We find a pair of novel correlation-induced resonances separated by an energy scale that depends exponentially on U. The effect is robust against a small detuning of the dot energy levels and occurs for arbitrary generic tunnel couplings. It should be observable in experiments on the basis of presently existing double-dot setups.

The coronary-subclavian-vertebral steal syndrome (CSVSS).

OBJECTIVE: Reverse flow in the internal thoracic artery (ITA) after coronary bypass surgery due to an occlusion or severe stenosis of the subclavian artery is a rare situation. Symptoms can be recurrent and intermittent angina pectoris in the case of a coronary-subclavian steal (CSSS) or-in addition with cerebral symptoms-in the case of a coronary-subclavian-vertebral steal syndrome (CSVSS). METHOD: We describe the cases of four patients with recurrent angina pectoris 5, 11, and 14 years as well as directly after coronary bypass surgery with LITA grafts to LAD. In two patients there was the additional aspect of vertebral steal symptoms with dizziness and intermittent drop attacks. RESULTS: A PTA of the subclavian occlusions in three cases was not feasible, so that three patients were operated on by extrathoracal approach and carotido-subclavian bypass (CSB) in two cases, and local thrombendarteriectomy of the subclavian and vertebral artery (TEA)+ -patchplasty in one case. Patient 4 was treated by PTA and stent placement into the subclavian artery. Antegrade flow in all four LITAs could be achieved resulting in immediate relief from angina pectoris and cerebral symptoms. Patients 1 and 3 showed no further symptoms with equal BP of the upper extremities and anterograde flow in the LITA grafts and vertebral artery at 10-month follow-up. Patient 2 unfortunately died from an unrelated cause (asthmatic state) 4 months after the operation despite an uneventful recovery. CONCLUSION: The occurrence of a CSSS or CSVSS after coronary bypass surgery with retrograde flow in the ITA graft (as described in our four patients) is a rare, but potentially hazardous, situation. If the subclavian occlusion is not amenable to endovascular strategies, the extrathoracal approach by CSB or local TEA and patchplasty provides an excellent means with good midterm and long-term results.

[Uterine adenomyosis in infertile patients: MR imaging findings and clinical conclusions]. / MRT der uterinen Adenomyose bei infertilen Patientinnen: Ergebnisse und klinische Rückschlüsse.

PURPOSE: To evaluate the clinical value of magnetic resonance imaging (MRI) of the uterus and the pelvis in infertile female with symptomatic endometriosis for the assessment of uterine morphology and function. MATERIALS AND METHODS: Forty-one infertile women (mean age: 33.2 years) with symptomatic endometriosis documented by laparoscopy were evaluated with high-field MRI (Sonata, Siemens) using T2- and T1-weighted sequences. In addition, the patients underwent hysterosalpingoscintigraphy (HSSG) for evaluation of the uterotubal transport capacity. Pathologic findings of the uterine junction zone were correlated with the laparoscopic results, clinical symptoms and uterotubal transport capacity. RESULTS: Adenomyosis was diagnosed on T2-weigthed MR-images in 35 (85.4 %) patients (focal adenomatosis in 26 patients and diffuse adenomatosis in 9). Patients showing signs of adenomyosis tended to be older than patients without adenomyosis (mean age 34.1 years vs. 30.1 years) and showed a longer history of symptomatic endometriosis. A positive transport capacity in HSSG was observed in 73.1 % (19/26) of the patients with focal adenomyosis and in only 22.2 % (2/9) of patients with diffuse adenomyosis. In 83.3 % (5/6) of the patients without signs of adenomyosis, a positive uterotubal transport was documented. CONCLUSION: MRI of the uterus is a helpful diagnostic tool for the diagnosis of adenomyosis and for planning further therapies. Patients with the diagnosis of adenomyosis showed a reduced uterotubal transport capacity that depended on the severity of adenomyotic changes and might be a possible cause of infertility.