The paper describes the Rosetta Lander named Philae and introduces its complement of scientific instruments. Philae was launched aboard the European Space Agency Rosetta spacecraft on 02 March 2004 ...and is expected to land and operate on the nucleus of 67P/Churyumov-Gerasimenko at a distance of about 3 AU from the Sun. Its overall mass is ~98 kg (plus the support systems remaining on the Orbiter), including its scientific payload of ~27 kg. It will operate autonomously, using the Rosetta Orbiter as a communication relay to Earth. The scientific goals of its experiments focus on elemental, isotopic, molecular and mineralogical composition of the cometary material, the characterization of physical properties of the surface and subsurface material, the large-scale structure and the magnetic and plasma environment of the nucleus. In particular, surface and sub-surface samples will be acquired and sequentially analyzed by a suite of instruments. Measurements will be performed primarily during descent and along the first five days following touch-down. Philae is designed to also operate on a long time-scale, to monitor the evolution of the nucleus properties. Philae is a very integrated project at system, science and management levels, provided by an international consortium. The Philae experiments have the potential of providing unique scientific outcomes, complementing by in situ ground truth the Rosetta Orbiter investigations.
A patient with bilateral congenital aplasia of the deep femoral arteries is described. The condition was accompanied by aneurysms of the popliteal arteries. Besides the academic interest of such an ...anatomical rarity, the abnormality is of clinical importance insofar as acute ischemia of the extremity may occur in the presence of superficial femoral artery occlusion.
In a retrospective study, we analyzed our experiences in 24 patients with acute ischemia from popliteal artery aneurysms over a period of 27 years and evaluated the value of a preoperative lytic ...therapy as an adjunct to surgical revascularization, compared to surgery alone. Preoperative urokinase therapy revealed a satisfactory improvement of the runoff in all cases. Follow-up angiography showed complete lysis in 6 and incomplete lysis in 3 of 9 patients. In contrast, in patients treated by surgery alone, postoperative angiography showed residual clots in all cases. The overall amputation rate was 25% (6/24) in 24 popliteal aneurysms with acute ischemia, including four patients with primary amputation for irreversible gangrene. Bypass grafting alone resulted in an early amputation rate of 9% (1/11) and occlusive complications of 45% (5/11) compared to no limb loss and no bypass complication in patients who underwent combined surgery and preoperative lysis (0/9). Our results underline the value of preoperative lytic therapy as an important factor in the management of acute ischemia in popliteal artery aneurysms.
The implantation of an aortic bifurcation graft (ABG) for treatment of occlusive (OD) and aneurysmal (AD) aortoiliac disease is a standard technique with good long-term results and a relatively low ...incidence of complications. In a retrospective review of our patients from 1964 to 1993 only 36/1520 patients were identified who required reoperation at the proximal aortic anastomosis after ABG. Indications were graft occlusion (15/36) and graft stenoses (2/36), refractory to graft thrombectomy, proximal aortic anastomotic aneurysms (11/36) or graft infection (8/36). Graft occlusion or stenosis most frequently led to aortic reoperation in the OD-group (53.5%), recurrent aneurysmal disease (37.5%) and graft infection (37.5%) were the dominant indications in the AD-group. Mean time interval to reoperation was shorter in cases of graft infection (35 +/- 33 months) as compared with graft stenosis (66 +/- 58 months), graft occlusion (86 +/- 49 months) or aortic anastomotic aneurysms (152 +/- 90 months). Of the reoperations, 92% were done electively, 8% as emergency procedures. The perioperative course was uneventful in 67% of patients. Overall mortality rate after elective revisional surgery was 3% but reached 66% in emergencies. Postoperative morbidity and mortality was related to preoperative morbidity and the urgency of surgery, not with the mode of aortic intervention nor indication.
If only one pedal artery is patent the vascular surgeon has to decide between primary amputation and a bypass. Between 1980 and 1990, 460 femoro-distal bypasses were performed in our clinic and 8% ...(39 cases) of these received a pedal reconstruction. At discharge from the hospital 85% of these grafts were patent. The primary goal of treatment, to maintain life and salvage the limb on the basis of a functioning bypass, was obtained in 82% of patients. After 1 year the secondary patency of our pedal reconstructions was 68%. Taking the mortality of amputations into account, vascular surgery to the foot arteries is preferable to amputation, whenever possible.
Most supra-aortic aneurysms are localized in the extracranial carotid and subclavian artery. Aneurysms of the brachiocephalic artery (BCA) represent a rather rare finding. Chronic arteriosclerotic ...changes are responsible for the majority of cases. Posttraumatic BCA damage is only occasionally encountered, complete vascular dissection by perforating injuries being the dominant causative mechanism. Although isolated BCA trauma after blunt thoracic contusion is rare, brachiocephalic injury in association with aortic lesions seems to be the second most common site of vascular injury after the aorta. Cases of isolated blunt BCA trauma documented in the literature to date usually involved a complete avulsion of the artery from the aortic arch or complete rupture near the aortic origin. We present an isolated case of posttraumatic BCA aneurysm in a woman involved in a car accident who suffered blunt chest trauma with a subtotal, near circumferential vessel wall dissection of only the intima and media. Clinical features, diagnostic procedure, surgical treatment, and trauma mechanisms of postcontusional BCA lesions are described and discussed in reference to the literature.
Between January 1988 and January 1994, 24 patients with heterologous vascular bypasses were examined with suspected diagnosis of a perigraft reaction (PGR). All patients were subjected to ultrasound ...and CT. PGR ist defined as a sterile inflammation along the course of a vascular prosthesis. The typical clinical presentation is a fluctuating tumour with a localised painless swelling. In all cases liquid formations could be confirmed by diagnostic imaging procedures; signs of infection could be excluded. The synopsis of the clinical presentation, the time interval after implantation of the prosthetic material and the signs of sonography and CT can reliably exclude infection of the prosthesis and confirm the diagnosis of a PGR.
Medicinal compounds from plants include bicyclo3.3.1nonane derivatives, the majority of which are polycyclic polyprenylated acylphloroglucinols (PPAPs). Prototype molecules are hyperforin, the ...antidepressant constituent of St. John's wort, and garcinol, a potential anticancer compound. Their complex structures have inspired innovative chemical syntheses, however, their biosynthesis in plants is still enigmatic. PPAPs are divided into two subclasses, named type A and B. Here we identify both types in Hypericum sampsonii plants and isolate two enzymes that regiodivergently convert a common precursor to pivotal type A and B products. Molecular modelling and substrate docking studies reveal inverted substrate binding modes in the two active site cavities. We identify amino acids that stabilize these alternative binding scenarios and use reciprocal mutagenesis to interconvert the enzymatic activities. Our studies elucidate the unique biochemistry that yields type A and B bicyclo3.3.1nonane cores in plants, thereby providing key building blocks for biotechnological efforts to sustainably produce these complex compounds for preclinical development.
