| 1. |
- Abbasi, R, et al.
(författare)
-
Extending the Search for Neutrino Point Sources with IceCube above the Horizon
- 2009
-
Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 103:22, s. 221102-
-
Tidskriftsartikel (refereegranskat)abstract
- Point source searches with the IceCube neutrino telescope have been restricted to one hemisphere, due to the exclusive selection of upward going events as a way of rejecting the atmospheric muon background. We show that the region above the horizon can be included by suppressing the background through energy-sensitive cuts. This improves the sensitivity above PeV energies, previously not accessible for declinations of more than a few degrees below the horizon due to the absorption of neutrinos in Earth. We present results based on data collected with 22 strings of IceCube, extending its field of view and energy reach for point source searches. No significant excess above the atmospheric background is observed in a sky scan and in tests of source candidates. Upper limits are reported, which for the first time cover point sources in the southern sky up to EeV energies.
|
|
| 2. |
- Fok, KF, et al.
(författare)
-
Spontaneous intracerebral hemorrhage caused by an unusual association of developmental venous anomaly and arteriovenous malformation
- 2006
-
Ingår i: Interventional neuroradiology : journal of peritherapeutic neuroradiology, surgical procedures and related neurosciences. - : SAGE Publications. - 1591-0199. ; 12:2, s. 113-121
-
Tidskriftsartikel (refereegranskat)abstract
- We describe three patients who presented with spontaneous intracerebral hemorrhage resulting from the close association of developmental venous anomaly (DVA) and arteriovenous malformation (AVM). Angioarchitecturally, either the DVA formed the draining pathway for the AVM or they shared a common venous channel. The AVMs were treated by targeted embolization and the DVAs were carefully preserved. It is suggested that the unusual association of an AVM with the less flexible DVA was the cause of hemorrhage.
|
|
| 3. |
|
|
| 4. |
|
|
| 5. |
|
|
| 6. |
- Stracke, C P, et al.
(författare)
-
Interneuronal systems of the cervical spinal cord assessed with BOLD imaging at 1.5 T.
- 2005
-
Ingår i: Neuroradiology. - : Springer Science and Business Media LLC. - 0028-3940 .- 1432-1920. ; 47:2, s. 127-33
-
Tidskriftsartikel (refereegranskat)abstract
- The purpose of this study was to investigate if functional activity with spinal cord somatosensory stimulation can be visualized using BOLD fMRI. We investigated nine healthy volunteers using a somatosensory stimulus generator. The stimuli were applied in three different runs at the first, third, and fifth finger tip of the right hand, respectively, corresponding to dermatomes c6, c7, and c8. The stimuli gave an increase of BOLD signal (activation) in three different locations of the spinal cord and brain stem. First, activations could be seen in the spinal segment corresponding to the stimulated dermatome in seven out of nine volunteers for c6 stimulation, two out of eight for c7, and three out of eight for c8. These activations were located close to the posterior margin of the spinal cord, presumably reflecting synaptic transmission to dorsal horn interneurons. Second, activation in the medulla oblongata was evident in four subjects, most likely corresponding to the location of the nucleus cuneatus. The third location of activation, which was the strongest and most reliable observed was inside the spinal cord in the c3 and c4 segments. Activation at these spinal levels was almost invariably observed independently of the dermatome stimulated (9/9 for c6, 8/8 for c7, and 7/8 for c8 stimulation). These activations may pertain to an interneuronal system at this spinal level. The results are discussed in relation to neurophysiological studies on cervical spinal interneuronal pathways in animals and humans.
|
|
| 7. |
|
|
| 8. |
- Zhao, WY, et al.
(författare)
-
Spontaneous mirror dissections of cervicocephalic arteries. Pathomechanical considerations
- 2006
-
Ingår i: Interventional neuroradiology : journal of peritherapeutic neuroradiology, surgical procedures and related neurosciences. - : SAGE Publications. - 1591-0199. ; 12:1, s. 73-78
-
Tidskriftsartikel (refereegranskat)abstract
- While so-called twin or mirror aneurysms constitute an established subgroup of multiple aneurysms, simultaneous spontaneous mirror dissections of cervicocephalic artery have not yet been reported as a particular entity. Among the patients treated at our institution since 1989, we identified 74 patients with spontaneous, non-traumatic dissections. Six of these cases presented with simultaneous bilateral dissections and four of the six patients had mirror dissections. Acute or chronic headache was present in all four cases. Additional clinical presentations consisted of impaired consciousness, cranial nerve palsy, and tinnitus. Angiography revealed irregular stenosis, dilatation or aneurysms located in the cervical ICA (internal carotid artery), VA (vertebral artery), or MCA (middle cerebral artery) without evident location bias. Although mirror dissections seems to be an exceptional finding, they may shed light on the vulnerability of different arterial segments to specific diseases. Similar to arterial aneurysm formation, pathogenesis of mirror dissection may involve an underlying “shared defect” in the endothelial cells, since these cells demonstrate a bilateral distribution during embryological development. This particular distribution therefore also provides a chronicle trail of the first trigger striking during embryonic development and demonstrates the segmental vulnerability to highly specific triggers.
|
|
