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- Al-Khateeb, S, et al.
(författare)
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Light-induced fluorescence studies on dehydration of incipient enamel lesions
- 2002
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Ingår i: Caries research. - : S. Karger AG. - 0008-6568 .- 1421-976X. ; 36:1, s. 25-30
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Tidskriftsartikel (refereegranskat)abstract
- Changes in the hydration state of enamel affect its optical qualities, such as light scattering and fluorescence. In this study, the rate of fluorescence loss was measured when incipient enamel lesions with different de-remineralization history were left to dehydrate. Four groups of lesions were studied. In groups A, B and C, the lesions were prepared in vitro in an acid-gel system. Group A was kept as control, and groups B and C were remineralized (4 weeks) without and with 1 ppm F in solution, respectively. Group D consisted of natural incipient lesions. Enamel fluorescence was measured for all lesions immediately after removal from water and subsequently at short intervals for 30 min. The change in fluorescence with dehydration varied between the groups. In lesions from groups A and B, it followed a double exponential decrease, while in lesions from groups C and D, it followed a mono-exponential decrease. In all groups, the fluorescence of sound surfaces declined mono-exponentially. The ‘fractional fluorescence difference’, defined as (L<sub>sound</sub> – L<sub>carious</sub> )/L<sub>sound</sub>, became constant after periods of dehydration of about 5, 5, 20 and 5 min for groups A to D, respectively. The observation of the change of fluorescence with dehydration should be taken into consideration when planning studies that use fluorescence as an assessment method. However, it might also be used to gain insight into the properties for fluid transport inside the various lesions, relevant to de-remineralization or fluoride treatments.
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| 2. |
- Al-Khateeb, Susan
(författare)
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Studies on the remineralization of white spot lesions : longitudinal assessment with quantitative light-induced fluorescence
- 1998
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The global aim of this work was to develop and test the light induced fluorescence method using either laser light or a regular, i.e. noncoherent light source for quantification of mineral changes in white spot lesions. Validation studies were carried out to establish the correlation between fluorescence loss and mineral loss. One study was performed to investigate the porosity of white spot lesions of different origins and its effect on the optical characteristics of a white spot lesion. Further, the remineralization process of "open lesions" was studied under different conditions: the effect of acid etching of white spot lesions was investigated in presence or absence of fluoride in an in vitro study. The effect of fluoride supplementation at regularly use of F dentifrice on the remineralization of white spot lesions was investigated in an in situ model. Moreover, the mineral changes in white spot lesions developed in vivo during orthodontic fixed appliance treatment were followed longitudinally. It was concluded that the laser fluorescence method is sensitive and valid for the quantification of mineral loss in natural incipient enamel lesions. Changes in enamel fluorescence reflected changes in mineral content during de- and remineralization processes in the enamel providing the basis for a quantitative method for assessment of mineral changes to a depth of about 450 µm in vitro, in situ, and in vivo. The light induced fluorescence method could operate using monochromatic laser light at the wave length 488 nm, or with a regular (noncoherent) white light source emerging from a Xenon gas-chargeable lamp. Addition of fluoride for the remineralization of "open lesions" caused redistribution of the minerals in the white spot lesions and blockage of their surface layer. In healthy young adults with normal salivary flow and good oral hygiene, fluoride supplementation to the regular use of F dentifrice did not further enhance the remineralization of artificially induced subsurface enamel lesions. Acid etching of white spot lesions enhanced the remineralization process of these lesions. Full remineralization of the so called "open lesions" was not obtained neither in vitro nor in the in vivo environment. Using the QLF method, it would be possible to register the rate of dehydration of a white spot lesion, thus providing information about the nature of that lesion regarding the characteristics of its surface layer.
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| 3. |
- Al-Khatib, A., et al.
(författare)
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Competition between collective and noncollective excitation modes at high spin in Ba-124
- 2006
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Ingår i: Physical Review C. Nuclear Physics. - 0556-2813 .- 1089-490X. ; 74:1
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Tidskriftsartikel (refereegranskat)abstract
- High-spin states in Ba-124 were investigated in two experiments using the Ni-64(Ni-64, 4n)Ba-124 reaction at three different beam energies. In-beam gamma-ray coincidences were measured with the Euroball and Gammasphere detector arrays. In the experiment with Euroball, the CsI detector array Diamant was employed to discriminate against charged-particle channels. Six new rotational bands were observed in Ba-124, and previously known bands were extended to higher spins. One of the bands shows a transition from collective to noncollective behavior at high spins. Configuration assignments are suggested on the basis of comparison with cranked shell model and cranked Nilsson-Strutinsky calculations.
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| 4. |
- Al-Khatib, A., et al.
(författare)
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High-spin states in Ba-124
- 2005
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Ingår i: Acta Physica Polonica B. - 0587-4254 .- 1509-5770. ; 36:4, s. 1029-1032
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Tidskriftsartikel (refereegranskat)abstract
- High-spin states in Ba-124 were populated using the Ni-64 (Ni-64,4n) Ba-124 reaction at beam energies of 255 and 261 MeV. Gamma-ray coincidences were measured using the EUROBALL detector array. The charged-particle detector array DIAMANT provided channel selection. The previously known rotational bands are extended to higher spins. Five new hands are observed, one of them extends up to the spin 40h region.
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| 5. |
- Al-Khatib, Ahmad, 1974
(författare)
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Sabîl
- 2012
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Ingår i: 321090 Institute du Monde Arabe.
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Konstnärligt arbete (övrigt vetenskapligt/konstnärligt)abstract
- Sabîl (Institut du Monde Arabe 321090) Ahmad joins up with percussionist Youssef Hbeisch on this CD of his own compositions, which includes comprehensive liner notes. 1. Khundî Ma'ak (Take me along) 7:18 2. Sifr El-Khurûj I - Musa (Exode I - Moses) 4:19 3. Sifr El-Khurûj II - Kan'ân (Exode II - Canaan) 1:52 4. Sifr El-Khurûj III - Nahrayn (Exode II - Two Rivers) 4:26 5. Bayyâ' El-Ward (The Rose Vendor) 5:46 6. Li Alix (For Alix) 5:08 7. Maqâm li Ghazzâ (Maqâm for Gaza) 4:39 8. Sabîl (On the Way) 4:39 9. 'Ors (Wedding) 4:37 10. Shadhâ (Fragrance) 4:35 11. Ya Halâlû yâ mâlû (Their Palestine) 5:38
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