Using sparsity information for iterative phase retrieval in x-ray propagation imaging.

For iterative phase retrieval algorithms in near field x-ray propagation imaging experiments with a single distance measurement, it is indispensable to have a strong constraint based on a priori information about the specimen; for example, information about the specimen's support. Recently, Loock and Plonka proposed to use the a priori information that the exit wave is sparsely represented in a certain directional representation system, a so-called shearlet system. In this work, we extend this approach to complex-valued signals by applying the new shearlet constraint to amplitude and phase separately. Further, we demonstrate its applicability to experimental data.

[Conception and evaluation of a group therapy intervention for patients with chronic pain disorders and applications for early retirement pensions]. / Konzeption und Evaluation einer sozialmedizinischen Patientenschulung für chronische Schmerzpatienten mit laufendem Rentenverfahren.

OBJECTIVE: Patients with chronic pain disorder are generally thought to be difficult to treat in psychosomatic rehabilitation. On average, their disorders tend to take a more chronic course than those of other patients, and they develop a higher rate of additional socio-medical problems, all of which increase the probability of therapy failure. Most of the time, such failures are attributed solely to the desire for early retirement and disability pensions, that is, a characteristic of the patient. However, a lack of specific therapeutic offers for patients with predominant psycho-social problems has also to be considered. The project described was designed to evaluate a newly developed socio-medical therapy module. This module aimed at bringing more transparency to the process of assessing occupational capabilities and work performance, thus improving the patients' motivation to participate in the rehabilitation program as well as the overall therapy outcome. METHODS: The project was implemented as a controlled, prospective evaluation study. A quasi-experimental 3-factorial design was employed, including two group factors (factor 1: socio-medical intervention [EG 1] vs. relaxation therapy module [EG 2]; factor 2: current application for premature pension vs. none; factor 3: repeated measurements [admission to inpatient therapy, discharge from the clinic, 6-months follow-up]). The treatment conditions for the experimental groups were realized according to an ABBA-scheme. Patients in both treatment conditions took part in pain disorder-specific coping groups and were also included in the regular inpatient treatment. At all three points of measurement, socio-demographic, socio-medical, symptomatic and motivational patient characteristics were obtained as dependent variables by use of well-established standardized patient surveys. In total, 206 patients suffering from a chronic pain disorder took part in the study (n [EG1]=100; n [EG2]=106). Both treatment groups were considered equal regarding relevant sample characteristics. RESULTS: The socio-medical intervention was equally well accepted by all patients. Patients of the first experimental group turned out to be better informed about socio-medical issues than members of the second experimental group. The rehabilitation treatment program as a whole was--independently of treatment group affiliation--highly effective. Despite contrary expectations, the socio-medical intervention did not have an additional (differential) therapeutic effect on the patients at all points of measurement, not even on those participants currently applying for retirement pensions. Also, there were no significant differences between the treatment groups regarding the days of sick leave within six months after discharge from inpatient rehabilitation. CONCLUSIONS: The original and possibly too ambitious goal of the project, namely to increase the rehabilitation success for patients with pain disorder and current pension applications by means of the therapeutic module labeled "social medicine", was not achieved. Nevertheless it is to be noted that this module was well received by the patients. Moreover, the authors consider it to be of high value in itself that this therapeutic module helps patients to become better informed.

[Potential of the water jet in cataract surgery]. / Was kann der Wasserstrahl in der Kataraktchirurgie?

UNLABELLED: Though cataract surgery is highly developed today, there are still problems such as endothelial cell loss after surgery and the occurrence of aftercataract. To reduce these complications we looked for techniques with a high degree of safety and precision. We found the water jet, an instrument already well established in liver surgery. We tested the possibility of improving the results of cataract surgery using the water jet method. METHODS: We performed cataract surgery--phacoemulsifikation and polishing of the capsule--on freshly enucleated porcine bulbs using water jet and by conventional procedures. By scanning electron microscope examination we compared the results. Additionally we emulsified human lens nuclei obtained by extracapsular cataract extraction using the water jet. RESULTS: The epithelial cells and lens fragments on the capsule were considerably reduced after the water jet procedure. CONCLUSION: The results show the possibility of improvement of cataract surgery by using the water jet. Further studies are necessary to adapt this technique to routine surgery in humans.

Ethidium bromide and hepatic mitochondrial structure in mice. A morphometric analysis.

Nine days after receiving a single injection of ethidium bromide - an inhibitor of mitochondrial DNA and its synthesis - mice were found to have enlarged mitochondria which were also reduced in number. The morphometric study revealed an increase of the mean mitochondrial volume, as well as an enlargement of the surface area of the mitochondrial inner membrane. However, the surface of the inner and outer membrane per unit volume of mitochondrion remained unchanged. These morphometric findings suggest mitochondrial growth, since mitochondrial inner membranes can be synthesized even in the presence of DNA-inhibiting ethidium bromide. In addition, morphometric analysis enables us to estimate the mean life span of hepatic mitochondria. In conclusion we may assume that since ethidium bromide induces not only a reduction of mitochondrial division but also an increase in the hepatic mitochondrial volume and inner membrane, the mitochondrial genome possibly fulfills a regulatory role in the mitochondrial and cytoplasmic systems for protein synthesis.