Search

Your search keyword '"Kolev V"' showing total 462 results
Start Over Author "Kolev V"
462 results on '"Kolev V"'

24. Contrast-enhanced MR Imaging versus Contrast-enhanced US: A comparison in glioblastoma surgery by using intraoperative fusion imaging

Author

Prada, F, Vitale, V, Del Bene, M, Boffano, C, Sconfienza, L, Pinzi, V, Mauri, G, Solbiati, L, Sakas, G, Kolev, V, D'Incerti, L, Di Meco, F, Prada F., Vitale V., Del Bene M., Boffano C., Sconfienza L. M., Pinzi V., Mauri G., Solbiati L., Sakas G., Kolev V., D'Incerti L., Di Meco F., Prada, F, Vitale, V, Del Bene, M, Boffano, C, Sconfienza, L, Pinzi, V, Mauri, G, Solbiati, L, Sakas, G, Kolev, V, D'Incerti, L, Di Meco, F, Prada F., Vitale V., Del Bene M., Boffano C., Sconfienza L. M., Pinzi V., Mauri G., Solbiati L., Sakas G., Kolev V., D'Incerti L., and Di Meco F.

Abstract

Purpose: To compare contrast material enhancement of glioblastoma multiforme (GBM) with intraoperative contrast-enhanced ultrasonography (US) versus that with preoperative gadolinium- enhanced T1-weighted magnetic resonance (MR) imaging by using real-time fusion imaging. Materials and Methods: Ten patients with GBM were retrospectively identified by using routinely collected, anonymized data. Navigated contrastenhanced US was performed after intravenous administration of contrast material before tumor resection. All patients underwent tumor excision with navigated intraoperative US guidance with use of fusion imaging between real-time intraoperative US and preoperative MR imaging. With use of fusion imaging, glioblastoma contrast enhancement at contrast-enhanced US (regarding location, morphologic features, margins, dimensions, and pattern) was compared with that at gadolinium-enhanced T1-weighted MR imaging. Results: Fusion imaging for virtual navigation enabled matching of realtime contrast-enhanced US scans to corresponding coplanar preoperative gadolinium-enhanced T1-weighted MR images in all cases, with a positional discrepancy of less than 2 mm. Contrast enhancement of gadolinium-enhanced T1-weighted MR imaging and contrast-enhanced US was superimposable in all cases with regard to location, margins, dimensions, and morphologic features. The qualitative analysis of contrast enhancement pattern demonstrated a similar distribution in contrast-enhanced US and gadolinium-enhanced T1-weighted MR imaging in nine patients: Seven lesions showed peripheral inhomogeneous ring enhancement, and two lesions showed a prevalent nodular pattern. In one patient, the contrast enhancement pattern differed between the two modalities: Contrast- enhanced US showed enhancement of the entire bulk of the tumor, whereas gadolinium-enhanced T1-weighted MR imaging demonstrated peripheral contrast enhancement. Conclusion: Glioblastoma contrast enhancement with contrast-enhanced US is supe

Published
2017

37. Control over a phase state of the laser plume ablated by femtosecond laser: Spatial pulse shaping.

Author

Gamaly, E.G., Rode, A.V., Uteza, O., Kolev, V., Luther-Davies, B., Bauer, T., Koch, J., Korte, F., and Chichkov, B.N.

Subjects
LASER ablation, ULTRASHORT laser pulses, FEMTOCHEMISTRY, PHASE modulation, LASERS, CHEMICAL vapor deposition
Abstract

The conditions for the formation of a fully atomized laser-ablated plume using subpicosecond laser pulses have been studied theoretically and implemented experimentally. It is shown that the low-intensity wings, which generally exist in the spatial distribution of laser intensity in the focal plane and can contain a substantial part of the incident laser energy, are responsible for low-threshold phase transformations of the target and this is the major source of particulates in the ablated plume. By truncating these wings with a simple aperture and positioning the target in the image plane of that aperture, particulates can be eliminated from the plume. This is demonstrated in experiments on deposition of Si films using the truncated beam in combination with the proper choice of laser fluence. This results in an almost totally atomized plume and consequently in droplet-free deposition of thin films. © 2004 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Published
2004
Full Text
View/download PDF

38. Ultrafast trapping times in ion implanted InP.

Author

Carmody, C., Boudinov, H., Tan, H. H., Jagadish, C., Lederer, M. J., Kolev, V., Luther-Davies, B., Dao, L. V., and Gal, M.

Subjects
ION implantation, OPTOELECTRONICS
Abstract

As[sup +] and P+ implantation was performed on semi-insulating (SI) and p-type InP samples for the purpose of creating a material suitable for ultrafast optoelectronic applications. SI InP samples were implanted with a dose of 1 × 10[sup 16]cm[sup -2] and p-type InP was implanted with doses between 1 × 10[sup 12] and 1 × 10[sup 16] cm[sup -2]. Subsequently, rapid thermal annealing at temperatures between 400 and 700 °C was performed for 30 sec. Hall-effect measurements, double-crystal x-ray diffraction, and time-resolved femtosecond differential reflectivity showed that, for the highest-annealing temperatures, the implanted SI InP samples exhibited high mobility, low resistivity, short response times, and minimal structural damage. Similar measurements on implanted p-type InP showed that the fast response time, high mobility, and good structural recovery could be retained while increasing the resistivity. [ABSTRACT FROM AUTHOR]

Published
2002
Full Text
View/download PDF

46. Control over a phase state of the laser plume ablated by femtosecond laser: spatial shaping

Author

Gamaly, E.G., Rode, A.V., Kolev, V., Uteza, O., Davies, B. Luther, Bauer, T., Koch, J., Korte, F., and Chichkov, B.N.

Subjects
Dielectric films -- Research, Dielectric films -- Optical properties, Thin films -- Research, Thin films -- Optical properties, Ablation (Vaporization technology) -- Research, Physics
Abstract

The crucial role of spatial distribution of the laser intensity across the focal spot on the phase state of the ablated plume has been demonstrated. The experimental implementation of this led to almost fully atomized plume and to a deposition of almost droplet-free thin films.

Published
2004

47. The position of event-related EEG activity in the local/global theory

Author

Kolev, V. and Yordanova, J.

Subjects
Electroencephalography, Neurology -- Research, Brain -- Localization of functions, Brain mapping -- Methods, Psychology and mental health
Abstract

The theory of local/global neocortical EEG dynamics responds to newly emerging conceptualizations in neuroscience. An extended application of the model to event-related EEG activity composed of distinctive global and local functional epochs with presumably different timing is proposed.

Published
2000

Catalog

Books, media, physical & digital resources
See catalog results