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We consider a scenario in which a dark matter can couple only to the top quark. The analysis is conducted by using the effective Lagrangian approach. In the light of the latest data on dark matter, we obtain a maximally allowed magnitude of the coupling between the dark matter and the top quark. The collider signature at the Large Hadron Collider is also discussed. [ABSTRACT FROM AUTHOR]

Despite improvement in adjuncts for thoracoabdominal aortic aneurysms (TAAA) repairs, many devastating complications remains after the surgery. Our experience with these aneurysms has been reviewed in order to identify those methods at risk of major morbidity, as well as which further improvements required. During last 16 years, 53 consecutive patients were operated on TAAA. The mean age was 58 years. Twenty patients had dissecting aneurysms and 13 patients had had prior aortic surgery. A femoro-femoral bypass was used to maintain distal aortic perfusion in most patients. Reimplantation of intercostal or lumbar arteries under the multi-segmental aortic clamping is consistent in our technique. Motor evoked potentials (MEP) were measured to monitor spinal cord protection since 2000. The hospital mortality was 9.4% (5/53), 22.2% (2/9) for emergency operation and 15.4% (2/13) for patients with prior aortic surgery. The mortality for the first and elective operations was 3.2% (1/31). No any neurologic dysfunction was observed in all patients including the hospital deaths. In view of clinical results, our adjuncts and techniques are useful for prevention of spinal cord ischemia during the TAAA surgery.

Objective: We present the impact of multisegmental aortic clamping under distal aortic perfusion and segmental artery reimplantation on the prevention of postoperative paraplegia during thoracoabdominal aortic graft replacement., Patients: During the last 14 years in 47 patients (age range: 22 to 82 years; average: 57,9 +/- 13,2 years; 16 females and 31 males) with thoracoabdominal aortic aneurysm a graft replacement was performed with adjuncts of normothermic partial bypass and multisegmental aortic clamping. As many patent segmental arteries as possible were reimplanted., Results: Five patients died during hospitalization, for an in-hospital mortality rate of 10,6 %. In the elective patients (n = 40), the hospital mortality rate was 7,5 %. The average number of segmental aortic clampings per patient was 2,83 +/- 1,19 times. In 39 patients (82,9 %), 117 segmental arteries were reimplanted or preserved by beveled anastomosis. Eighty-three out of 117 segmental arteries (70,9 %) were located between TH9 and L2. Postoperative paraplegia/paraparesis did not occur in any patient., Conclusion: In view of our results reimplantation of as many segmental arteries as possible under multisegmental aortic clamping with adequate distal aortic perfusion can be recommended for effective prevention of spinal cord ischemia in TAAA surgery.