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  • 1
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 72 (1992), S. 5423-5428 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Photoion and photoelectron yields were measured for poly(methylmethacrylate) in the photon energy region of 8–40 eV using synchrotron radiation. Further, the valence-band structure was investigated with ultraviolet photoelectron spectra and valence effective Hamiltonian calculations. A significant difference was observed between the photon energy dependencies of photoion and photoelectron yields. The threshold energy for photoion emission was found to be 10.5 eV, while that for photoelectron emission was 8.5 eV, indicating holes created near the valence-band top do not contribute to the ion emission. At the higher-energy region, the ion emission efficiency was found to be enhanced in the photon energy region of 17–28 eV. The difference between the threshold energies of photoion and photoelectron emission and the enhancement of the photoion emission are discussed in conjunction with the valence-band structure.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Neuroradiology 31 (1990), S. 533-536 
    ISSN: 1432-1920
    Keywords: Extracranial vertebral artery aneurysm ; Neurofibromatosis ; Detachable balloon ; Endovascular occlusion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary An extracranial vertebral artery aneurysm in a patient with neurofibromatosis is described. The aneurysm was treated by endovascular balloon occlusion of the proximal vetebral artery. The details of the therapeutic management are discussed, and the vascular manifestations of neurofibromatosis are reviewed.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 0942-0940
    Keywords: Subarachnoid haemorrhage ; chronic cerebral vasospasm ; calcium antagonist ; AT877 ; HA 1077
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The initial dose-escalating clinical trial of a novel calcium antagonist, AT877, in patients with aneurysmal subarachnoid haemorrhage is reported. AT877 is characterized by its strong spasmolytic activity, its inhibition of intracellular calcium ion activity, and the inhibiton of several protein kinases. A total of 113 patients (Hunt and Hess grades I to IV) who had undergone surgery within 3 days of aneurysmal rupture entered the study. Patients were divided into 5 groups according to the total daily dose of AT877: I: 20 mg; II: 40 mg; III: 60 mg; IV: 90 mg; and V: 120–180 mg. AT877 was given by intravenous infusion over 30 min two or three times a day for 14 days after surgery. Although AT877 did not completely abolish angiographic vasospasm, severe vasospasm was seen less frequently in patients given higher doses. Vasospasm was the cause of a poor clinical outcome (Glasgow outcome scale rating 3 or greater) in 19%, 7%, 9%, 8%, and 6% of the patients in groups I to V, respectively. The results indicated a favourable clinical effect of AT877 at doses above 40 mg per day. Only mild hypotension was seen, even when 60 mg of AT877 was infused over 30 min. AT877 appears to be effective in patients with subarachnoid haemorrhage. Part of its effect may be attributable to protection of the brain from ischaemic insults due to chronic cerebral vasospasm. However, the drug still needs to be evaluated in a placebo-controlled double-blind trial (which is currently being carried out).
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Acta neurochirurgica 114 (1992), S. 147-150 
    ISSN: 0942-0940
    Keywords: Intrasellar haematoma ; transsphenoidal surgery ; hypopituitarism ; pituitary apoplexy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary This report describes a rare case of primary intrasellar haematoma in a 66 year-old man with hypopituitarism. Computerized tomography (CT) and magnetic resonance imaging (MRI) showed an intrasellar cystic lesion with small suprasellar extension. Transsphenoidal surgery revealed that the lesion was a chronic haematoma, without evidence of a tumour or vascular anomaly. Pathological diagnosis confirmed this. This is the first report of a chronic intrasellar haematoma, which is probably primary.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 0942-0940
    Keywords: Cerebral vasospasm ; haemorrhagic infarction ; intracranial aneurysm ; normovolaemic induced hypertension therapy ; subarachnoid haemorrhage ; Swan-Ganz catheter
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We showed that normovolaemic induced hypertension therapy was effective in reducing ischaemic symptoms attributed to cerebral vasospasm in 41 patients after subarachnoid haemorrhage. By inducing hypertension to 25% to 50% above normal systolic arterial blood pressure, we observed that in 17 of 24 cases (71%) neurological deficits improved. In four cases of haemorrhagic infarction, the blood pressure rose to over 50% of systolic arterial pressure, and a low density area was confirmed on computerized tomography (CT) scan prior to vasospasm. Induced hypertension was therefore not considered when a low density area was revealed on CT scan. Restriction of fluid input is usually a factor in producing hypovolaemia after a neurosurgical operation. Intravascular volume expansion has been reported effective in reversing ischaemic deficits. However, according to Poiseuille's equation, increasing blood volume to a state of hypervolaemia can not enhance flow. The cerebral blood flow (CBF) was raised by increasing perfusion pressure, reducing viscosity, or increasing blood vessel diameter. Intravascular volume expansion elevates not only systemic arterial pressure, but also pulmonary artery wedge pressure over 18 mmHg and cardiac index over 2.2. Since pulmonary oedema and congestive heart failure may develop, one should monitor haemodynamic parameters with the Swan-Ganz catheter as a preventive measure. We emphasize that normovolaemic induced hypertension, maintaining haemodynamics subset 1 of the comparable haemodynamic subsets, is effective in raising perfusion pressure of CBF.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 0942-0940
    Keywords: Ischaemic oculopathy ; venous stasis retinopathy ; neovascular glaucoma ; rubeosis iridis ; STA-MCA anastomosis ; EC-IC bypass surgery
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Effects of STA-MCA anastomosis on two patients with neovascular glaucoma due to occlusion of the internal carotid artery are presented. Both patients improved in visual acuity and central retinal artery pressure as well as in signs of transient ischaemic attack. Postoperative angiography showed a marked decrease in collateral flow through the ophthalmic artery, which is reversed from the normal direction, with the development of blood flow through the anastomosis. Discussion is offered indicating that the lack of collateral flow through both the anterior and posterior communicating arteries is important in addition to occlusion of the internal carotid artery in order to produce full-blown ischaemic oculopathy such as venous stasis retinopathy, neovascular glaucoma or rubeosis iridis. It is stressed that EC-IC bypass surgery should be performed soon after the appearance of ischaemia and before the development of neovascular glaucoma or rubeosis iridis in order to obtain normal vision. In ischaemic oculopathy the results of EC-IC bypass can be evaluated objectively and quantitatively by many noninvasive neuro-ophthalmological tests which are important in discussing the efficacy of the bypass surgery.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 0942-0940
    Keywords: Endothelin ; neuropeptide Y ; angiotensin II ; cerebral arteries ; cerebral circulation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We have studied the effect of endothelin, an endothelium-derived peptide, on isolated canine and bovine cerebral arteries in vitro and on canine vertebral blood flow (VBF) in vivo. Endothelin produced a dose-dependent contraction of canine and bovine arterial smooth muscle with ED50 values ranging from 4 to 8 nM. The response to endothelin developed slowly and persisted as a sustained contraction. Maximal contraction by endothelin required the presence of extracellular calcium and was independent of the presence of endothelium. The maximal contraction produced by endothelin was approximately 2–3 times greater than that produced by neuropeptide Y or angiotensin II. The injection of endothelin into the vertebral artery decreased vertebral blood flow (VBF) dose-dependently without affecting systemic blood pressure or heart rate. The decrease in VBF produced by endothelin was long-lasting, like that produced by neuropeptide Y, but more potent. The present data, together with our previous study demonstrating that the intracisternal injection of endothelin induces an unusually long-lasting decrease in the basilar artery diameter angiographically, suggests that endothelin may act as a long-acting vasoconstrictor in cerebral vascular disease.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    International journal of theoretical physics 31 (1992), S. 59-60 
    ISSN: 1572-9575
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract It is shown that the standard model of the electroweak interactions holds at an infinite sublayer quark level, insofar as we consider the weak isospin doublet (u ∞L,u ∞L cp , whereu ∞is an infinite number of quarks at an infinite sublayer level.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    International journal of theoretical physics 31 (1992), S. 2043-2045 
    ISSN: 1572-9575
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We assume that the electron (e −), neutrino (v e), and gauge bosons (W ±,Z 0) are composed of only two kinds of particles, an ultimate particleu ∞ at an infinite sublayer quark level and a chargeless fermiont, such thate −=(u ∞ cp u ∞ cp l),V e =(u ∞ u ∞ cp l,W +=(u ∞ u ∞),W −=(u ∞ cp u ∞ cp andZ 0=(u ∞ u ∞ cp . It is then shown thatCP is violated in weak interactions associated with these electron, neutrino, and gauge bosons.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    International journal of theoretical physics 31 (1992), S. 521-524 
    ISSN: 1572-9575
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract In a previous paper we proposed the infinite sublayer quark model, in which there exists an infinite number of quarksu ∞ and antiquarksu ∞ c at an infinite sublayer level. By applying the standard model of the electroweak interactions to the weak isospin doublets (u ∞L ,u ∞L cp ) T and (u ∞L ,u ∞L ct ) T , it is shown that there exists only one phase factor, which causesCP violation.
    Type of Medium: Electronic Resource
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