Thickness Decreases (thickness + decrease)

Distribution by Scientific Domains


Selected Abstracts


Functional and morphological changes in the eyes of Behçet's patients with uveitis

ACTA OPHTHALMOLOGICA, Issue 2 2010
Masaru Takeuchi
Abstract. Purpose:, Behçet's disease (BD) is a chronic, recurrent, multisystem disorder, and serious ocular involvement may lead to blindness. In some BD patients, latent tissue damage caused by recurrent ocular inflammation is not reflected by visual acuity or ophthalmoscopic findings. In this study, we evaluated the morphological and functional changes of ocular features related to duration of uveitis from onset in BD patients, and analysed their association with visual acuity. Methods:, Thirty-eight eyes of 20 patients with ocular BD were enrolled. Eyes with marked complications such as cataract, glaucoma, cystoid macular oedema, macular degeneration and optic atrophy were excluded from the study. During clinical remission of ocular inflammation, perimetric sensitivity and retinal thickness were measured by Micro Perimeter 1 (MP-1) and optical coherence tomography (OCT), respectively. The relationship between MP-1 and OCT findings, best-corrected visual acuity (BCVA) converted to logarithm of the minimum angle of resolution (logMAR) and duration from initial onset of uveitis were analysed statistically. Results:, logMAR correlated with perimetric sensitivity measured with MP-1 at the fovea, inner macula and outer macula, but not with retinal thickness based on OCT. The duration of uveitis correlated significantly with logMAR and with OCT-based retinal thickness at the fovea, inner macular and outer macula, but not with MP-1-derived retinal perimetric sensitivity. No correlation was found between OCT-based retinal thickness and the corresponding MP-1-derived retinal sensitivity at the fovea, inner macula or outer macula. Conclusion:, These results demonstrate that visual acuity, retinal perimetric sensitivity and retinal thickness decrease with an increase in the duration of uveitis in BD patients, but that retinal perimetric sensitivity is relatively preserved among these factors. [source]


Changes in the bucco-lingual thickness of the mandibular alveolar process and skeletal bone mineral density in dentate women: a 5-yr prospective study

EUROPEAN JOURNAL OF ORAL SCIENCES, Issue 2 2005
Grethe Jonasson
After tooth extraction there is a great interindividual variation in the remodelling pattern of the alveolar process in edentulous areas, with some individuals losing little bone and others undergoing extensive resorption. However, little is known about possible longitudinal changes in the dentate region of the alveolar process of adults and if these are related to alterations in the skeletal bone mineral density (BMD). In a prospective study, on two occasions, 5-yr apart, the BMD of 117 women was determined in the distal forearm by using dual-energy X-ray absorptiometry, and the bucco-lingual thickness of the mandibular alveolar process was measured on dental casts by using a dial calliper. A decrease in the mean alveolar thickness, exceeding a cut-off value of 0.1 mm, was found in 60% of the women and an increase was found in 3% of the individuals. This decrease was 0.22 ± 0.20 mm in the posterior region and 0.16 ± 0.19 mm in the anterior region. The changes in alveolar thickness in the posterior region were significantly correlated to the BMD changes both on the mid-crestal level site and on the cervical level site. We conclude that the bucco-lingual thickness decreases with age in the dentate alveolar process, possibly owing to periosteal resorption related to skeletal bone loss. [source]


Influence of insulating barrier thickness on the magnetoresistance properties of a magnetic tunnel junction with Zr-alloyed Al oxide barrier

PHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 8 2004
Chul-Min Choi
Abstract We have investigated the magnetoresistive properties and thermal and electrical stability of a magnetic tunnel junction (MTJ) with a high-quality, ultra-thin Zr-alloyed Al oxide (ZrAl oxide) barrier of below 1.0 nm. We obtained the highest bias voltage and breakdown voltage of 711 mV and 1.75 V for a 1.6-nm-thick barrier. The resistance drops from 1850 , to 72 , as the ZrAl thickness decreases from 1.6 to 0.6 nm, respectively. A significant TMR (Tunneling Magneto-resistance) value of 17% and a junction resistance of 98 , were obtained for a MTJ with a ZrAl oxide barrier thickness of 0.8 nm. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]


Spacer layer thickness effects on the photoluminescence properties of InAs/GaAs quantum dot superlattices

PHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 3 2003
B. Ilahi
Abstract InAs/GaAs vertically stacked self-assembled quantum dot (QD) structures with different GaAs spacer layer thicknesses are grown by solid source molecular beam epitaxy (SSMBE) and investigated by transmission electron microscopy (TEM) and photoluminescence (PL) spectroscopy. An increase in the polarization anisotropy is observed when the spacer layer thickness decreases. For a 10 monolayer (ML) thick inter-dots GaAs spacer, the TEM image shows an increase in the QD size when moving to the upper layer accompanied by the generation of dislocations. Consequently, the corresponding temperature-dependant PL properties are found to exhibit an unusual behaviour. The main PL peak is quenched at a temperature around 190 K giving rise to a broad background correlated with the formation of a miniband in the growth direction due to the strong interlayer coupling. For a thicker GaAs spacer layer (30 ML), multilayer QDs align vertically in stacks with no apparent structural defects. Over the whole temperature range, the excitonic band energies are governed by the Varshni empirical relation using InAs bulk parameters and the PL line width shows a slight monotonic increase. For a thinner GaAs interlayer, the thermal activation energies of the carrier emission out of the quantum dots are found to be considerably small (about 25 meV) due to the existence of defects. By combining these structural and optical results, we can conclude that a thinner GaAs spacer has a poorer quality. (© 2003 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]


Evaluation of the atrophogenic potential of different glucocorticoids using optical coherence tomography, 20-MHz ultrasound and profilometry; a double-blind, placebo-controlled trial

BRITISH JOURNAL OF DERMATOLOGY, Issue 4 2006
M. Coßmann
Summary Background, Skin atrophy is one of the main side-effects of topical corticosteroid therapy. Although the use of high-frequency ultrasound is an established method that has been studied previously, it allows measurements of the slow-reacting dermal thickness only. Objectives, To investigate the decreasing epidermal thickness, which occurs earlier, we used optical coherence tomography (OCT), a high-resolution noninvasive imaging technique, and compared it with 20-MHz ultrasound and profilometry. Patients/methods, In this double-blind placebo-controlled trial 20 healthy volunteers applied four different corticosteroids and the cream base formulation as placebo to the volar part of both arms once a day over a 4-week period. The epidermal thickness, the dermal thickness and the skin surface roughness were assessed using OCT, high-frequency ultrasound and profilometry. Results, Each of the three methods allowed the detection and monitoring of significant corticosteroid-induced skin atrophy and its reversibility. The changes correlated with the potency of the steroids. The epidermal thickness decreased significantly in all test areas, even in the placebo and the untreated fields. As expected, the reduction in epidermal thickness was more pronounced and could be detected earlier by OCT than the reduction of dermal thickness using ultrasound. The epidermal surface roughness investigated using profilometry showed a slight smoothing. Conclusions, OCT allows a simple, fast and noninvasive in vivo measurement of the epidermal thickness. To evaluate the atrophogenic potential of corticosteroids it is more suitable than high-frequency ultrasound as epidermal thickness decreases earlier. In addition, epidermal thickness is a more sensitive indicator of steroid atrophy as the degree of thinning is much higher compared with the dermal atrophy. Profilometry might give further information; however, it would not be suitable for clinical use as the results were generally less pronounced. In the future, OCT might be useful to detect corticosteroid-induced side-effects at the beginning for monitoring the therapy. [source]