2,000 research outputs found
Low-Dose Radiotherapy of Painful Heel Spur/Plantar Fasciitis as an Example of Treatment Effects in Benign Diseases
Degenerative changes in the plantar fascia may cause the soâcalled âpainful heelâ with typical projections of tenderness. This condition is often associated with a plantar heel spur. Radiotherapy with low doses (LDâEBRT) has been well known for its antiâinflammatory potential. In the recent years, several microbiological mechanisms were elucidated to explain immunomodulation by LDâEBRT. Furthermore, a randomized study proved the clinical efficacy of this therapy in plantar fasciitis. Two other trials defined a fractionation schedule of 6 Ă 0.5 Gy twice weekly as the new standard therapy. Taken together, LDâEBRT is an effective and safe therapeutic option for patients over 30 years of age and after exclusion of pregnancy. In case of an insufficient response, a second course can be offered to the patient. There are still open questions concerning target volume definition and fractionation of LDâEBRT. Furthermore, studies randomizing LDâEBRT with other conservative therapeutic approaches are missing
Comment on Singly Ionizing 100-MeV/amu Câ¶âș+He Collisions with Small Momentum Transfer
In a recent article, Kouzakov suggested that experimental resolution effects can be responsible for discrepancies between measured and calculated fully differential cross sections for the ionization of helium by fast C6+ impact. They further asserted that projectile-coherence effects have no influence on the measured cross sections. In this Comment, we reiterate that the experimental resolution can only explain part of the discrepancies. Furthermore, we note that the conclusion regarding the role of projectile coherence neglects potential interference between first- and higher-order transition amplitudes
Doubly Differential Electron-Emission Spectra in Single and Multiple Ionization of Noble-Gas Atoms by Fast Highly-Charged-Ion Impact
Low-energy electron emission spectra are studied in collisions of 3.6 MeV/amu Au53+ ions with neon and argon atoms for well-defined degrees of target ionization. We calculate doubly differential cross sections as functions of the recoil-ion charge state in the continuum-distorted-wave with eikonal initial-state approximation using a binomial analysis of the total and differential ionization probabilities, and compare them with the present and with previously published experimental data. Very good agreement is found for the single-ionization spectra and for double ionization of neon, while some discrepancies are observed in the spectra for double and triple ionization of argon
Dupuytren's DiseaseâEtiology and Treatment
BACKGROUND: The worldwide prevalence of Dupuytrenâs disease (DD) is 8%. DD is a chronic disease for which there is no cure. Various treatments are available. METHODS: This review is based on pertinent publications retrieved by a selective search in PubMed and Embase. RESULTS: Genetic factors account for 80% of the factors involved in causing this disease. Diabetes mellitus, hepatic diseases, epilepsy, and chronic occupational use of vibrating tools are also associated with it. Limited fasciectomy is the most common treatment and is considered the reference standard. Possible complications include persistent numbness in areas where the skin has been elevated, cold sensitivity, and stiffness, with a cumulative risk of 3.6 â39.1% for all complications taken together. The recurrence rate at 5 years is 12â73%. Percutaneous needle fasciotomy is the least invasive method, with more rapid recovery and a lower complication rate than with limited fasciectomy. 85% of patients have a recurrence after an average of 2.3 years. Radiotherapy can be given before contractures arise in patients with high familial risk, or postoperatively in selected patients with a very high individual risk of recurrence. CONCLUSION: Although DD is not curable, good treatments are available. Recurrences reflect the pathophysiology of the disease and should not be considered complications of treatment. When counseling patients about the available treatment options, particularly the modalities and timing of surgery, the physician must take the patientâs degree of suffering into account. Nowadays, fast recovery from surgery and less postoperative pain are a priority for many patients. Different surgical methods can be used in combination. It remains difficult to predict the natural course and the time to postoperative recurrence in individual patients; these matters should be addressed in future studies
Chemical spray pyrolysis of Tl-Ba-Ca-Cu-O high-T(sub c) superconductors for high-field bitter magnets
The deposition of Tl-Ba-Ca-Cu-O thick films by spray pyrolyzing a Ba-Ca-Cu-O precursor film and diffusing thallium into the film to form the superconducting phase is examined. This approach was taken to reduce exposure to thallium and its health and safety hazards. The Tl-Ba-Ca-Cu-O system was selected because it has very attractive features which make it appealing to device and manufacturing engineering. Tl-Ba-Ca-Cu-O will accommodate a number of superconducting phases. This attribute makes it very forgiving to stoichiometric fluctuations in the bulk and film. It has excellent thermal and chemical stability, and appears to be relatively insensitive to chemical impurities. Oxygen is tightly bound into the systems, consequently there is no orthorhombic (conductor) to tetragonal (insulator) transition which would affect a component's lifetime. More significantly, the thallium based superconductors appear to have harder magnetic properties than the other high-Tc oxide ceramics. Estimates using magnetoresistance measurements indicate that at 77 K Tl2Ba2CaCu2O10 will have an upper critical field, H(sub c2) fo 26 Tesla for applied fields parallel to the c-axis and approximately 1000 Tesla for fields oriented in the a-b plane. Results to date have shown that superconducting films can be reproducibly deposited on 100 oriented MgO substrates. One film had a zero resistance temperature of 111.5 K. Furthermore, x ray diffraction analysis of the films showed preferential c-axis orientation parallel to the plane of the substrate. These results have now made it possible to consider the manufacture of a superconducting tape wire which can be configured into a topology useful for high-field magnet designs. The research which leads to the preparation of these films and plans for further development are reviewed
Prospective Evaluation of Low-Dose External Beam Radiotherapy (LD-EBRT) for Painful Trapeziometacarpal Osteoarthritis (Rhizarthrosis) on Pain, Function, and Quality of Life to Calculate the Required Number of Patients for a Prospective Randomized Study
Background: Retrospective studies have described the effectiveness of low-dose radiotherapy (LD-EBRT) in painful arthrosis of small finger joints, but two recent prospective studies have yielded ambiguous results. To generate accurate data for the planning of a trial, we conducted a prospective, monocentric, observational study to describe the effects of LD-EBRT as precisely as possible. Methods: Twenty-five consecutive patients with symptomatic trapeziometacarpal (TMC) arthrosis were irradiated with 6 Ă 0.5 Gy. Before, 3, and 12 months after LD-EBRT, we assessed subjective endpoints (modified âvon-Pannewitz scoreâ, 10-point visual analogue scale (VAS), âpatient-rated wrist evaluationâ (PRWE)), and objective measurements (âactive range of motionâ (AROM), Kapandji index, grip strength, pinch grip). Results: At 3/12 months, 80%/57% reported partial and 4%/18% complete remission according to the âvon-Pannewitzâ score. VAS âoverall painâ significantly decreased from a median of seven (IQR 4) at baseline to three (IQR 6; p = 0.046) and to two (IQR 2; p = 0.013). Similar results were obtained for VAS âpain during exerciseâ, VAS âpain during daytimeâ, and VAS âfunctionâ. âPRWE overall scoreâ was reduced from 0.5 at baseline (SD 0.19) to 0.36 (SD 0.24, p = 0.05) and to 0.27 (SD 0.18, p = 0.0009). We found no improvements of the objective endpoints (AROM, Kapandji, grip strength) except for flexion, which increased from 64° (SD 12°) at baseline to 73° (SD 9.7°, p = 0.046) at 12 months. Conclusions: We recommend the PRWE score as a useful endpoint for further studies for this indication. To prove a 15% superiority over sham irradiation, we calculated that 750 patients need to be prospectively randomized
Simultaneous Projectile-Target Ionization: A Novel Approach to (e, 2e) Experiments on Ions
A kinematically complete experiment for simultaneous ionization of a projectile and target has been performed for 3.6 MeV/u C2+ on He collisions measuring the final vector momenta of the He1+ recoil ion and of two electrons (projectile, target) in coincidence with the emerging C3+ projectile. The feasibility of an event-by-event separation of the various reaction channels, among them the ionization of C2+ by the interaction with a quasifree target electron, is demonstrated in agreement with six-body classical trajectory Monte Carlo calculations, paving the way to kinematically complete electron-ion scattering experiments
Ultracold chemical reactions of a single Rydberg atom in a dense gas
Within a dense environment (atoms/cm) at
ultracold temperatures (), a single atom excited to a
Rydberg state acts as a reaction center for surrounding neutral atoms. At these
temperatures almost all neutral atoms within the Rydberg orbit are bound to the
Rydberg core and interact with the Rydberg atom. We have studied the reaction
rate and products for Rb Rydberg states and we mainly observe a
state change of the Rydberg electron to a high orbital angular momentum ,
with the released energy being converted into kinetic energy of the Rydberg
atom. Unexpectedly, the measurements show a threshold behavior at for the inelastic collision time leading to increased lifetimes of the
Rydberg state independent of the densities investigated. Even at very high
densities (), the lifetime of a
Rydberg atom exceeds at compared to
at . In addition, a second observed reaction mechanism,
namely Rb molecule formation, was studied. Both reaction products are
equally probable for but the fraction of Rb created drops to below
10% for .Comment: 13 pages, 13 figure
Probing Scattering Wave Functions Close to the Nucleus
Recently, three-dimensional imaging of the ejected electrons following 100ââMeV/amu C6+ single ionization of helium led to the observation of a new structure not predicted by theory [M. Schulz et al., Nature (London) 422, 48 (2003)]. Instead of the usual ârecoil lobeâ centered on the momentum-transfer axis, a ring-shaped structure centered on the beam axis was observed. New measurements at 2ââMeV/amu exhibit a similar structure, which is now predicted by theory. We argue that the same theory failed at 100ââMeV/amu because the faster projectiles probe distances much closer to the nucleus, where our multiple-scattering model is expected to break down
Quantum Electronics
Contains reports on three research projects.Joint Services Electronics Program (Contract DAAB07-75-C-1346
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