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41.
42.
Volvulus of the sigmoid colon is exceptionally rare in infancy and childhood. In this report volvulus of the sigmoid colon in a neonate was found associated with maldevelopment of the mesocolon. 相似文献
43.
Background
There is paucity of literature describing complex elbow trauma in the pediatric population. We described a case of an uncommon pediatric elbow injury comprised of lateral condyle fracture associated with posterolateral dislocation of elbow. 相似文献44.
45.
46.
Time domain (TD) diffuse optical measurement systems are being applied to neuroimaging, where they can detect hemodynamics changes associated with cerebral activity. We show that TD systems can provide better depth sensitivity than the more traditional continuous wave (CW) systems by gating late photons, which carry information about deep layers of the brain, and rejecting early light, which is sensitive to the superficial physiological signal clutter. We use an analytical model to estimate the contrast due to an activated region of the brain, the instrumental noise of the systems, and the background signal resulting from superficial physiological signal clutter. We study the contrast-to-noise ratio and the contrast-to-background ratio as a function of the activation depth and of the source-detector separation. We then present experimental results obtained with a time-gated instrument on the motor cortex during finger-tapping exercises. Both the model and the experimental results show a similar contrast-to-noise ratio for CW and TD, but that estimation of the contrast is experimentally limited by background fluctuations and that a better contrast-to-background ratio is obtained in the TD case. Finally, we use the time-gated measurements to resolve in depth the brain activation during the motor stimulus. 相似文献
47.
Boverman G Miller EL Li A Zhang Q Chaves T Brooks DH Boas DA 《Physics in medicine and biology》2005,50(17):3941-3956
Spectroscopic diffuse optical tomography (DOT) can directly image the concentrations of physiologically significant chromophores in the body. This information may be of importance in characterizing breast tumours and distinguishing them from benign structures. This paper studies the accuracy with which lesions can be characterized given a physiologically realistic situation in which the background architecture of the breast is heterogeneous yet highly structured. Specifically, in simulation studies, we assume that the breast is segmented into distinct glandular and adipose regions. Imaging with a high-resolution imaging modality, such as magnetic resonance imaging, in conjunction with a segmentation by a clinical expert, allows the glandular/adipose boundary to be determined. We then apply a two-step approach in which the background chromophore concentrations of each region are estimated in a nonlinear fashion, and a more localized lesion is subsequently estimated using a linear perturbational approach. In addition, we examine the consequences which errors in the breast segmentation have on estimating both the background and inhomogeneity chromophore concentrations. 相似文献
48.
The Israeli experience discloses the relationship between the traditional altruistic basis of organ donation and the new alternatives
based on a utilitarian conception of unrelated compensated donation. Although organ trafficking in Israel was dramatically
intensified, cadaveric and living-related donations decreased. Reforms in living donations, such as evaluation committees
for unrelated directed donors, were insignificant in terms of meeting the demand of patients and reducing the volume of trafficking.
It is our contention that battling organ trafficking should provide patients with a realistic alternative for kidney donations.
Our model of regulated nondirect paid donations is planned to legalize significant compensation for the unrelated donors drawing
individuals from falling into the trap of organ traders. This program, together with uncompromised penalties, would hopefully
eradicate organ trafficking. 相似文献
49.
Epileptic seizures and epilepsy: definitions proposed by the International League Against Epilepsy (ILAE) and the International Bureau for Epilepsy (IBE) 总被引:27,自引:9,他引:18
The International League Against Epilepsy (ILAE) and the International Bureau for Epilepsy (IBE) have come to consensus definitions for the terms epileptic seizure and epilepsy. An epileptic seizure is a transient occurrence of signs and/or symptoms due to abnormal excessive or synchronous neuronal activity in the brain. Epilepsy is a disorder of the brain characterized by an enduring predisposition to generate epileptic seizures and by the neurobiologic, cognitive, psychological, and social consequences of this condition. The definition of epilepsy requires the occurrence of at least one epileptic seizure. 相似文献
50.
Augustijn PB Parra J Wouters CH Joosten P Lindhout D van Emde Boas W 《Neurology》2001,57(6):1108-1111
Ring chromosome 20 mosaicism is associated with dysmorphic features, mental retardation, and intractable seizures, including recurrent episodes of nonconvulsive status epilepticus. The authors' findings in four children, all without dysmorphic features, indicate that mental deterioration and frequent subtle nocturnal frontal lobe seizures, associated with a characteristic EEG pattern, represent prominent additional clinical features not previously described in this syndrome. This emphasizes the importance of full-night video-EEG in children with frontal lobe seizures and cognitive deterioration. 相似文献