803 research outputs found
A single ion as a three-body reaction center in an ultracold atomic gas
We report on three-body recombination of a single trapped Rb^+ ion and two
neutral Rb atoms in an ultracold atom cloud. We observe that the corresponding
rate coefficient K_3 depends on collision energy and is about a factor of 1000
larger than for three colliding neutral Rb atoms. In the three-body
recombination process large energies up to several 0.1eV are released leading
to an ejection of the ion from the atom cloud. It is sympathetically recooled
back into the cloud via elastic binary collisions with cold atoms. Further, we
find that the final ionic product of the three-body processes is again an
atomic Rb^+ ion suggesting that the ion merely acts as a catalyzer, possibly in
the formation of deeply bound Rb_2 molecules.Comment: 5 pages, 4 figure
A Versatile Simulation Environment of FTC Architectures for Large Transport Aircraft
We present a simulation environment with 3-D stereo visualization facilities destined for an easy setup and versatile assessment of fault detection and diagnosis based fault tolerant control systems. This environment has been primarily developed as a technology demonstrator of advanced reconfigurable flight control systems and is based on a realistic six degree of freedom flexible aircraft model. The aircraft control system architecture includes a flexible fault detection and diagnosis system and a reconfigurable nonlinear dynamic inversion based controller, able to handle different fault situations
Dramatic regression and bleeding of a duodenal GIST during preoperative imatinib therapy: case report and review
<p>Abstract</p> <p>Background</p> <p>Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors of the digestive tract. The majority of GISTs is located in the stomach. Only 3-5% of GISTs are located in the duodenum associated with an increased risk of gastrointestinal bleeding as primary manifestation. With response rates of up to 90%, but complications like bleeding due to tumor necrosis in 3%, imatinib mesylate dramatically altered the pre- and postoperative therapy for GIST patients.</p> <p>Case presentation</p> <p>A 58-year-old female patient presented with acute upper gastrointestinal bleeding 2 weeks after a giant GIST of the duodenum had been diagnosed. Neoadjuvant imatinib therapy had been initiated to achieve a tumor downsizing prior to surgery. During emergency laparotomy a partial duodenopancreatectomy was performed to achieve a complete resection of the mass. Histology revealed a high-malignancy GIST infiltrating the duodenal wall. Adjuvant imatinib therapy was initiated. At follow-up (19 months) the patient is still alive and healthy.</p> <p>Conclusion</p> <p>Giant GISTs of the duodenum are rare and - in contrast to other localizations - harbour a higher risk of serious bleeding as primary manifestation. Tumor necrosis and tumor bleeding are rare but typical adverse effects of imatinib therapy especially during treatment of high-malignancy GIST. In GIST patients with increased risk of tumor bleeding neoadjuvant imatinib therapy should thoroughly be performed during hospitalization. In cases of duodenal GIST primary surgery should be considered as treatment alternative.</p
3D printed fracture reduction guides planned and printed at the point of care show high accuracy - a porcine feasibility study.
PURPOSE
After surgical treatment of comminuted diaphyseal femoral and tibial fractures, relevant malalignment, especially rotational errors occur in up to 40-50%. This either results in a poor clinical outcome or requires revision surgery. This study aims to evaluate the accuracy of reduction if surgery is supported by 3D guides planned and printed at the point of care.
METHODS
Ten porcine legs underwent computed tomography (CT) and 3D models of femur and tibia were built. Reduction guides were virtually constructed and fitted to the proximal and distal metaphysis. The guides were 3D printed using medically approved resin. Femoral and tibial comminuted diaphyseal fractures were simulated and subsequently reduced using the 3D guides. Postoperative 3D bone models were reconstructed to compare the accuracy to the preoperative planning.
RESULTS
Femoral reduction showed a mean deviation ± SD from the plan of 1.0 mm ± 0.9 mm for length, 0.9° ± 0.7° for varus/valgus, 1.2° ± 0.9° for procurvatum/recurvatum and 2.0° ± 1.7° for rotation. Analysis of the tibial reduction revealed a mean deviation ± SD of 2.4 mm ± 1.6 mm for length, 1.0° ± 0.6° for varus/valgus, 1.3° ± 1.4° for procurvatum/recurvatum and 2.9° ± 2.2° for rotation.
CONCLUSIONS
This study shows high accuracy of reduction with 3D guides planned and printed at the point of care. Applied to a clinical setting, this technique has the potential to avoid malreduction and consecutive revision surgery in comminuted diaphyseal fractures.
LEVEL OF EVIDENCE
Basic Science
Decoy oligodeoxynucleotide againstactivator protein-1 reducesneointimal proliferation after coronaryangioplasty in hypercholesterolemic minipigs
AbstractObjectivesWe sought to demonstrate, in an appropriate animal model, that co-medication with a transcription factor-blocking agent limits restenosis after percutaneous transluminal coronary angioplasty (PTCA).BackgroundEnhanced synthesis in the vessel wall of endothelin-1 (ET-1), a powerful co-mitogen for vascular smooth muscle cells, appears to be one mechanism that promotes restenosis after PTCA. Deformation-induced expression of prepro-ET-1 is governed by the transcription factor, activator protein-1 (AP-1).MethodsAn anti-AP-1 decoy oligodeoxynucleotide (dODN) strategy was devised in which the dODN-containing solution (20 nmol) was administered locally through a Dispatch catheter into the coronary arteries of hypercholesterolemic minipigs at the time of PTCA (AVE-GFX stent).ResultsTreatment with an AP-1 dODN, mimicking the consensus binding site of the transcription factor, significantly reduced neointimal formation in the coronary arteries of hypercholesterolemic minipigs (n = 10 to 12), compared with vehicle-treated coronary arteries, after four weeks of follow-up (neointimal area 2.64 ± 0.33 vs. 4.81 ± 1.04 mm2[mean ± SEM]; p < 0.05). This effect was maintained after eight weeks (neointimal area 2.04 ± 0.22 mm2; n = 3) and correlated with a reduction in both nuclear translocation of AP-1 and ET-1 synthesis in the vessel wall 48 h after PTCA (n = 4). In contrast, an AP-1 mutant dODN, to which the transcription factor does not bind, showed no effect on neointimal formation at either time point (n = 3 to 7). Moreover, a consensus dODN directed against CCAAT/enhancer binding protein (C/EBP), another deformation-sensitive transcription factor, did not significantly affect neointimal formation after four weeks (n = 3).ConclusionsThese findings demonstrate the feasibility, efficacy and specificity of the anti-AP-1 dODN approach to the treatment of restenosis, which principally but not exclusively targets deformation-induced ET-1 synthesis in the vessel wall. Provided that these findings can be extrapolated to the situation of patients with coronary artery disease, the observed extent of the inhibitory effect of the AP-1 dODN treatment suggests that this co-medication may greatly reduce the incidence of in-stent restenosis
The impact of early surgical intervention in free intestinal perforation: a time-to-intervention pilot study
PURPOSES: An abdominal inflammatory focus is the second most often source of sepsis with a high risk of death in surgical intensive care units. By establishing evidence-based bundled strategies the surviving sepsis campaign provided an optimized rapid and continuous treatment of these emergency patients. Hereby the hospital mortality decreased from 35 to 30%. Sepsis treatment is based on three major therapeutic elements: surgical treatment (source control), antiinfective treatment, and supportive care. The international guidelines of the surviving sepsis campaign were updated recently and recommend rapid diagnosis of the infection and source control within the first 12h after the diagnosis (grade 1c). Interestingly this recommendation is mainly based on studies on soft tissue infections.
METHODS: In this retrospective analysis 76 septic patients with an intraabdominal inflammatory focus were included. All patients underwent surgery at different time-points after diagnosis.
RESULTS: With 80% patients of the early intervention group had an improved overall survival (vs. 73% in the late intervention group).
CONCLUSIONS: Literature on the time dependency of early source control is rare and in part contradicting. Results of this pilot study reveal that immediate surgical intervention might be of advantage for septic emergency patients. Further multi-center approaches will be necessary to evaluate, whether the TTI has any impact on the outcome of septic patients with intestinal perforation
Survival, functional outcome and satisfaction of first revision total knee arthroplasty at a mean eleven-year follow-up.
PURPOSE
Providing long-term outcome data after rTKA and compare one- versus two-stage and septic versus aseptic revisions.
METHODS
This study represents a single-center retrospective study of first rTKAs performed for any reason with a final follow-up of a minimum of five years. Outcome parameters included stability assessment ROM, radiologic assessment, HSS score, KSS score, OKS score, EQ-5D-3L and VAS. 44 patients were included in the study. Subgroups analysis of one- versus two-stage revision and septic versus aseptic revision was performed.
RESULTS
The leading causes of rTKA in this mean 11 year follow-up study were aseptic loosening (36%) and periprosthetic joint infection (27%). At the final follow-up, there was a 89% survivorship of the implants. Patients showed a ROM of 114 ± 13°, HSS score of 78 ± 12, KKS objective score of 77 ± 16, KSS expectation and satisfaction score of 32 ± 11, KSS functional activity score of 50 ± 20, OKS of 30 ± 9, VAS of 53 ± 25 and EQ-5D index of 0.649. Functional outcome scores were not significantly altered in the analyzed subgroups.
CONCLUSIONS
In our 11Â years follow-up, we obtained 89% implant survivorship. Measurements regarding functional outcome and pain showed results in the medium range of the respective scores, while patient satisfaction lay in the upper third. No significant differences in outcome scores between one- and two-stage revisions and septic versus aseptic revisions were observed. Level of Evidence Level III, retrospective cohort study
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