| 1. |
- Owens, Frank J., et al.
(författare)
-
Unusual room temperature ferromagnetism in bulk sintered GaP doped with copper
- 2007
-
Ingår i: IEEE transactions on magnetics. - 0018-9464 .- 1941-0069. ; 43:6, s. 3043-3045
-
Tidskriftsartikel (refereegranskat)abstract
- Robust room temperature ferromagnetism is obtained in single phase Gallium Phosphide doped with Cu2+ prepared by simple solid state reaction route. The saturation magnetization at 300 K is 1.5 x 10(-2) emu/g and the coercivity was found to be 125 Oe. A strong ferromagnetic resonance signal confirms the long range magnetic order which persists to temperatures as high as 739 K. X-ray absorption spectroscopy (XAS) indicate that Cu is in a +2 state. Ab initio calculations also show that the ferromagnetic ordering is energetically favorable in Cu doped GaP. When the spin-orbit coupling is included we get an enhanced total magnetic moment of 0.31 mu(B) with a local moment on Cu 0.082 and on P 0.204 mu(B). per atom.
|
|
| 2. |
- Gupta, A., et al.
(författare)
-
High-temperature ferromagnetism in Cu-doped GaP by SQUID magnetometry and ferromagnetic resonance measurements
- 2006
-
Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 74:22
-
Tidskriftsartikel (refereegranskat)abstract
- The search for ferromagnetism above room temperature in semiconductors doped with paramagnetic ions has intensified in recent years because of the potential of combining magnetic information storage and electronic switching in one spintronic device. Here we report an observation of ferromagnetism well above room temperature in gallium phosphide doped with Cu2+ detected by ferromagnetic resonance and SQUID magnetometry. Other important features of the results in this p-type Cu-doped GaP are the high Curie temperature above 700 K significantly higher than previous observations, the relatively simple low-temperature bulk sintering process used to synthesize the material, which will significantly reduce the cost of large-scale production, and the use of copper as the dopant rather than manganese, which precludes ferromagnetic clusters or magnetic alloy impurities as the origin of the ferromagnetism. Ab initio calculations also show the existence of ferromagnetism in Cu-doped GaP. When the spin-orbit coupling is included, the total moment is enhanced and we get a total magnetic moment of 0.31 mu(B) with a local moment on Cu 0.082 and on P 0.204 mu(B).
|
|
| 3. |
- Moat, R. J., et al.
(författare)
-
Residual Stresses in Inertia-Friction-Welded Dissimilar High-Strength Steels
- 2009
-
Ingår i: Metallurgical and Materials Transactions A - Physical Metallurgy and Materials Science. - : Springer Science and Business Media LLC. - 1073-5623. ; 40A:9, s. 2098-2108
-
Tidskriftsartikel (refereegranskat)abstract
- The welding of dissimilar alloys is seen increasingly as a way forward to improve efficiencies in modern aeroengines, because it allows one to tailor varying material property demands across a component. Dissimilar inertia friction welding (IFW) of two high-strength steels, Aermet 100 and S/CMV, has been identified as a possible joint for rotating gas turbine components and the resulting welds are investigated in this article. In order to understand the impact of the welding process and predict the life expectancy of such structures, a detailed understanding of the residual stress fields present in the welded component is needed. By combining energy-dispersive synchrotron X-ray diffraction (EDSXRD) and neutron diffraction, it has been possible to map the variations in lattice spacing of the ferritic phase on both sides of two tubular Aermet 100-S/CMV inertia friction welds (as-welded and postweld heat-treated condition) with a wall thickness of 37 mm. Laboratory-based XRD measurements were required to take into account the variation in the strain-free d-spacing across the weld region. It was found that, in the heat-affected zone (HAZ) slightly away from the weld line, residual stress fields showed tensile stresses increasing most dramatically in the hoop direction toward the weld line. Closer to the weld line, in the plastically affected zone, a sharp drop in the residual stresses was observed on both sides, although more dramatically in the S/CMV. In addition to residual stress mapping, synchrotron XRD measurements were carried out to map microstructural changes in thin slices cut from the welds. By studying the diffraction peak asymmetry of the 200-alpha diffraction peak, it was possible to demonstrate that a martensitic phase transformation in the S/CMV is responsible for the significant stress reduction close to the weld line. The postweld heat treatment (PWHT) chosen to avoid any overaging of the Aermet 100 and to temper the S/CMV martensite resulted in little stress relief on the S/CMV side of the weld.
|
|
| 4. |
- Wiltfang, J., et al.
(författare)
-
Consensus Paper of the WFSBP Task Force on Biological Markers of Dementia : The role of CSF and blood analysis in the early and differential diagnosis of dementia
- 2009
-
Ingår i: Revista de Psiquiatria Clinica. - 0101-6083. ; 36, s. 1-16
-
Forskningsöversikt (refereegranskat)abstract
- Aging of population, and increasing life expectancy result in an increasing number of patients with dementia. This symptom can be a part of a completely curable disease of the central nervous system (e.g, neuroinflammation), or a disease currently considered irreversible (e.g, Alzheimer's disease, AD). In the latter case, several potentially successful treatment approaches are being tested now, demanding reasonable standards of pre-mortem diagnosis. Cerebrospinal fluid and serum analysis (CSF/serum analysis), whereas routinely performed in neuroinflammatory diseases, still requires standardization to be used as an aid to the clinically based diagnosis of AD. Several AD-related CSF parameters (total tau, phosphorylated forms of tau, A beta peptides, ApoE genotype, p97, etc.) tested separately or in a combination provide sensitivity and specificity in the range of 85%, the figure commonly expected from a good diagnostic tool. In this review, recently published reports regarding progress in neurochemical pre-mortem diagnosis of dementias are discussed with a focus on an early and differential diagnosis of AD. Novel perspectives offered by recently introduced technologies, e.g, fluorescence correlation spectroscopy (FCS) and surface enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI-TOF MS) are briefly discussed.
|
|
| 5. |
- Wiltfang, J, et al.
(författare)
-
Consensus paper of the WFSBP Task Force on Biological Markers of Dementia: the role of CSF and blood analysis in the early and differential diagnosis of dementia.
- 2005
-
Ingår i: The world journal of biological psychiatry : the official journal of the World Federation of Societies of Biological Psychiatry. - : Informa UK Limited. - 1562-2975. ; 6:2, s. 69-84
-
Forskningsöversikt (refereegranskat)abstract
- Aging of population, and increasing life expectancy result in an increasing number of patients with dementia. This symptom can be a part of a completely curable disease of the central nervous system (e.g, neuroinflammation), or a disease currently considered irreversible (e.g, Alzheimer's disease, AD). In the latter case, several potentially successful treatment approaches are being tested now, demanding reasonable standards of pre-mortem diagnosis. Cerebrospinal fluid and serum analysis (CSF/serum analysis), whereas routinely performed in neuroinflammatory diseases, still requires standardization to be used as an aid to the clinically based diagnosis of AD. Several AD-related CSF parameters (total tau, phosphorylated forms of tau, Abeta peptides, ApoE genotype, p97, etc.) tested separately or in a combination provide sensitivity and specificity in the range of 85%, the figure commonly expected from a good diagnostic tool. In this review, recently published reports regarding progress in neurochemical pre-mortem diagnosis of dementias are discussed with a focus on an early and differential diagnosis of AD. Novel perspectives offered by recently introduced technologies, e.g, fluorescence correlation spectroscopy (FCS) and surface enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI-TOF MS) are briefly discussed.
|
|
| 6. |
- Aibinu, A.M., et al.
(författare)
-
A New Method of Correcting Uneven Illumination Problem in Fundus Images
- 2007
-
Konferensbidrag (refereegranskat)abstract
- Recent advancements in signal and image processing have reduced the time of diagnoses, effort and pressure on the screeners by providing auto diagnostic tools for different diseases. The success rate of these tools greatly depend on the quality of acquired images. Bad image quality can significantly reduce the specificity and the sensitivity which in turn forces screeners back to their tedious job of manual diagnoses. In acquired fundus images, some areas appear to be brighter than the other, that is areas close to the center of the image are always well illuminated, hence appear very bright while areas far from the center are poorly illuminated hence appears to be very dark. Several techniques including the simple thresholding, Naka Rushton (NR) filtering technique and histogram equalization (HE) method have been suggested by various researchers to overcome this problem. However, each of these methods has limitations at their own and hence the need to develop a more robust technique that will provide better performance with greater flexibility. A new method of compensating uneven (irregular) illumination in fundus images termed global-local adaptive histogram equalization using partially-overlapped windows (GLAPOW) is proposed in this paper. The developed algorithm has been tested and the results obtained show superior performance when compared to other known techniques for uneven illumination correction.
|
|
| 7. |
- Aibinu, A.M., et al.
(författare)
-
Automatic Diagnosis of Diabetic Retinopathy from Fundus Images Using Digital Signal and Image Processing Techniques
- 2007
-
Konferensbidrag (refereegranskat)abstract
- Automatic diagnosis and display of diabetic retinopathy from images of retina using the techniques of digital signal and image processing is presented in this paper. The acquired images undergo pre-processing to equalize uneven illumination associated with the acquired fundus images. This stage also removes noise present in the image. Segmentation stage clusters the image into two distinct classes while the abnormalities detection stage was used to distinguish between candidate lesions and other information. Methods of diagnosis of red spots, bleeding and detection of vein-artery crossover points have also been developed in this work using the color information, shape, size, object length to breadth ration as contained in the acquired digital fundus image. Furthermore, two graphical user interfaces (GUIs) have also been developed during this work; the first is for the collection of lesion data information and was used by the ophthalmologist in marking images for database while the second GUI is for automatic diagnosing and displaying of the result in a user friendly manner. The algorithm was tested with a separate set of 25 fundus images. From this, the result obtained for microaneurysms and haemorrhages diagnosis shows the appropriateness of the method.
|
|
| 8. |
- Iqbal, Muhammad Imran, et al.
(författare)
-
Detection of Vascular Intersection in Retina Fundus Image Using Modified Cross Point Number and Neural Network Technique
- 2008
-
Konferensbidrag (refereegranskat)abstract
- Vascular intersection can be used as one of the symptoms for monitoring and diagnosis of diabetic retinopathy from fundus images. In this work we apply the knowledge of digital image processing, fuzzy logic and neural network technique to detect bifurcation and vein-artery cross-over points in fundus images. The acquired images undergo preprocessing stage for illumination equalization and noise removal. Segmentation stage clusters the image into two distinct classes by the use of fuzzy c-means technique, neural network technique and modified cross-point number (MCN) methods were employed for the detection of bifurcation and cross-over points. MCN uses a 5x5 window with 16 neighboring pixels for efficient detection of bifurcation and cross over points in fundus images. Result obtained from applying this hybrid method on both real and simulated vascular points shows that this method perform better than the existing simple cross-point number (SCN) method, thus an improvement to the vascular point detection and a good tool in the monitoring and diagnosis of diabetic retinopathy. ©2008 IEEE.
|
|
| 9. |
- Moore, Sophie E., et al.
(författare)
-
Use of stable-isotope techniques to validate infant feeding practices reported by Bangladeshi women receiving breastfeeding counseling
- 2007
-
Ingår i: American Journal of Clinical Nutrition. - 0002-9165 .- 1938-3207. ; 85:4, s. 1075-1082
-
Tidskriftsartikel (refereegranskat)abstract
- Background: The World Health Organization recommends exclusive breastfeeding until age 6 mo. Studies relying on mothers' self-reported behaviors have shown that lactation counseling increases both the rate and duration of exclusive breastfeeding. Objective: We aimed to validate reported infant feeding practices in rural Bangladesh; intakes of breast milk and nonbreast-milk water were measured by the dose-given-to-the mother deuterium dilution technique. Design: Subjects were drawn from the large-scale Maternal and Infant Nutrition Interventions, Matlab, study of combined interventions to improve maternal and infant health, in which women were randomly assigned to receive either exclusive breastfeeding counseling or standard health care messages. Data on infant feeding practices were collected by questionnaire at monthly visits. Intakes of breast milk and nonbreast-milk water were measured in a subsample of 98 mother-infant pairs (mean infant age: 14.3 wk) and compared with questionnaire data reporting feeding practices. Results: Seventy-five of the 98 subjects reported exclusive breastfeeding. Mean (±SD) breast milk intake was 884 ± 163 mL/d in that group and 791 ± 180 mL/d in the group reported as nonexclusively breastfed (P = 0.0267). Intakes of nonbreast-milk water were 40 ± 80.6 and 166 ± 214 mL/d (P < 0.0001), respectively. Objective cross-validation using deuterium dilution data showed good accuracy in reporting of feeding practices, although apparent misreporting was widely present in both groups. Conclusions: The dose-given-to-the-mother deuterium dilution technique can be applied to validate reported feeding behaviors. Whereas this technique shows that the reports of feeding practices were accurate at the group level, it is not adequate to distinguish between feeding practices in individual infants.
|
|
