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Biomedical subjects

T Yildirim

Publications and source records attributed to T Yildirim.

At least 19 recordsLinked to original sources
PubMed2002

A case of Castleman's disease with "downhill" varices in the absence of superior vena cava obstruction.

Downhill esophageal varices", classically defined as those that develop in the upper region of the esophagus, are less common than the "uphill" type, which is usually produced by portal hypertension. Various causes of downhill varices have been reported, but mediastinal tumor is the most common responsible lesion. Castleman's disease, or angiofollicular lymph node hyperplasia, is a rare pathological process of unknown etiology that usually develops in the mediastinum. We report the case of a 60-year-old woman whose large esophageal varices were detected incidentally. The cause was a mediastinal mass which was diagnosed as Castleman's disease on histopathological examination of a surgical specimen. This patient's varices most likely formed as a result of copious blood drainage from the tumor into the esophageal veins. Evidence for this was the lack of the classic downhill pattern, the absence of superior vena cava obstruction, and the fact that the varices resolved after the tumor was removed. It is our opinion that this type of varices should be renamed, and we suggest that "overflow varices" would be an appropriate term.

Castleman Disease↗
PubMed2001

Tunable adsorption on carbon nanotubes.

We investigated the adsorption of a single atom, hydrogen and aluminum, on single-wall carbon nanotubes from first principles. The adsorption is exothermic, and the associated binding energy varies inversely as the radius of the zigzag tube. We found that the adsorption of a single atom and related properties can be modified continuously and reversibly by the external radial deformation. The binding energy on the high curvature site of the deformed tube increases with increasing radial deformation. The effects of curvature and radial deformation depend on the chirality of the tube.

Journal Article↗
PubMed2001

Giant anharmonicity and nonlinear electron-phonon coupling in MgB2: a combined first-principles calculation and neutron scattering study.

First-principles calculations of the electronic band structure and lattice dynamics for the new superconductor MgB (2) are carried out and found to be in excellent agreement with our inelastic neutron scattering measurements. The numerical results reveal that the E(2g) in-plane boron phonons near the zone center are very anharmonic and strongly coupled to the planar B sigma bands near the Fermi level. This giant anharmonicity and nonlinear electron-phonon coupling is key to quantitatively explaining the observed high T(c) and boron isotope effect in MgB (2).

Journal Article↗
PubMed2001

MRI of neurologic complications in end-stage renal failure patients on hemodialysis: pictorial review.

End-stage renal disease patients who have been on long-term hemodialysis tend to develop central nervous system complications. The most common neurologic complications in this patient group include white matter changes, cerebral atrophy, osmotic demyelination syndrome, dialysis encephalopathy, hypertensive encephalopathy, intracranial hemorrhage, infarct, sinus thrombosis, and infection. Clinical evaluation of these patients is somehow complicated and MRI is important before establishment of the therapy. The purpose of this article is to illustrate the range of MRI findings of neurologic complications in end-stage renal failure patients on hemodialysis with etiologic factors.

Atrophy↗
PubMed2001

Osteoid osteoma in the base of the coracoid process of the scapula. Excision by anterior approach: a case report.

Osteoid osteoma in the base of the coracoid process of the scapula is very rare and diagnosis and treatment often is delayed. A lesion in this atypical location may seem surgically unreachable. This report is of a case of osteoid osteoma in the base of coracoid process in a 14-year-old female. The lesion had been diagnosed as a nontumorous condition and overlooked for four years. Computed tomography and magnetic resonance imaging revealed a nidus in the base of the coracoid process. The en bloc excision of the osteoid osteoma was managed by an anterior approach using an osteotomy of the coracoid process. A 12-month follow-up examination revealed no symptoms and computed tomography showed bone healing with no recurrence of the tumor.

Adolescent↗