Imaging and manipulation of the competing electronic phases near the Mott metal-insulator transition.

The complex interplay between the electron and lattice degrees of freedom produces multiple nearly degenerate electronic states in correlated electron materials. The competition between these degenerate electronic states largely determines the functionalities of the system, but the invoked mechanism remains in debate. By imaging phase domains with electron microscopy and interrogating individual domains in situ via electron transport spectroscopy in double-layered Sr(3)(Ru(1-x)Mn(x))(2)O(7) (x = 0 and 0.2), we show in real-space that the microscopic phase competition and the Mott-type metal-insulator transition are extremely sensitive to applied mechanical stress. The revealed dynamic phase evolution with applied stress provides the first direct evidence for the important role of strain effect in both phase separation and Mott metal-insulator transition due to strong electron-lattice coupling in correlated systems.

Ferromagnetic stability in Fe nanodot assemblies on Cu(111) induced by indirect coupling through the substrate.

We report collective ferromagnetic behavior with high Curie temperatures (T(c)) in Fe dot assemblies supported by the Cu(111) surface. Our ability to tune the average size and spacing of the individual dots allows us to conclude that enhanced magnetic anisotropy cannot account for this high-T(c) ferromagnetic order. Because our Monte Carlo simulations have ruled out the dipolar interaction as the dominant factor in this system, we attribute the origin of the ferromagnetic order to indirect exchange coupling via the Cu(111) substrate.

Decay characteristics of surface mounds with contrasting interlayer mass transport channels.

The decay characteristics of three-dimensional (3D) islands formed on surfaces are investigated theoretically considering two types of interlayer mass transport mechanisms. If an adatom on a given layer can easily descend from any site along the periphery of the layer, an optimal island slope and a constant terrace width will be selected during the decay. In contrast, if the adatom can descend primarily through selective (such as kinked) sites, the decay will be accompanied by a gradual increase in the island slope. These generic conclusions provide the basis for a microscopic understanding of the decay of nanostructures in fcc(111) and fcc(100) metal homoepitaxy and are applicable to other systems as well.

Evolution of two-dimensional wormlike nanoclusters on metal surfaces.

A pinch-off phenomenon is discovered in the evolution of 2D wormlike nanoclusters formed in homoepitaxial adlayers. This feature is shown to distinguish mass transport via periphery diffusion from other mechanisms. Continuum modeling of such evolution accurately describes experimental observations, particularly if one incorporates the anisotropy in step-edge line tension.

Shockwave lithotripsy and pacemakers: experience with 20 cases.

Lithotripsy treatment of urinary tract calculi initially excluded patients with cardiac pacemakers. Continued research and clinical study of patient outcomes has promoted a change in that initial concept. The Oklahoma Lithotripsy Center has successfully treated 20 patients with various types of pacemakers. No significant cardiovascular events occurred during treatment. Patients should be evaluated before the procedure by a cardiologist, and dual-chamber pacemakers should be reprogrammed to the single-chamber mode. Patients who cannot tolerate this should not undergo SWL. Rate-responsive pacemakers should be programmed to the non-rate-responsive (VVI) mode. The pacemaker should be at least 5 cm from the blast path. With these precautions and careful monitoring, SWL can be performed safely in most patients with pacemakers.

Lithotripsy for retained common duct stones: a quasi-urological procedure.

A protocol for bile duct lithotripsy was formulated in early 1988 after review of the literature and encouragement by gastroenterologists. Seven cases have been treated at our center and are being reported to explain our current concept of this therapy. Failure of the Food and Drug Administration to approve gallstone lithotripsy has complicated the promulgation of this procedure.

Saralasin test as a diagnostic and prognostic aid in renovascular hypertensive patients subjected to renal operation.

A positive saralasin test in patients with angiographic evidence of renovascular disease and other positive functional tests gives further assurance that these patients will achieve normal or substantially reduced blood pressure postoperatively. In our experience with proved renovascular hypertension there was a 19 per cent incidence of falsely negative saralasin tests. Therefore, saralasin should not be used as the sole screening test in hypertensive patients suspected of having surgically correctable lesions. There is a direct correlation between elevated renin activity and a positive saralasin test. In some patients saralasin may be more sensitive than any other currently used test to detect overactivity of the renin-angiotensin system. This would determine those patients with technical errors in renin sampling and assays. Of the 16 patients (all normotensive) who had 6-month followup tests 5 had elevated peripheral renin activity, probably owing to furosemide stimulation. Of these 5 patients 2 had a positive postoperative saralasin test, raising the question of potential falsely positive responses in cases of essential hypertension and coincidental non-functional renal artery stenosis. Patients with high renin essential hypertension may respond to saralasin, even in the absence of renal artery lesions. A saralasin test should be done in a hospital where all specific conditions can be met and potential complications handled promptly.

Lower extremity amputation: review of 110 cases.

Very significant morbidity and mortality continue to accompany lower extremity amputations. In this study 90 patients underwent 110 amputations over a 4 year period. The overall complication rate was 40 per cent and the overall mortality rate 12.2 per cent. The patients at greatest risk were the above knee amputees greater than 60 years of age with peripheral vascular disease. Amputation of the lower extremity must be recognized as a major, life-threatening procedure. Careful preoperative evaluation of cardiac, pulmonary, and nutritional status along with efforts to prevent sepsis, pneumonia, pulmonary embolism, gastrointestinal ulceration, and renal failure are necessary if the mortality accompanying these procedures is to be reduced.

Transitional cell carcinoma: cause of refractory cancer of prostate.

Four cases with a diagnosis of adenocarcinoma of the prostate are presented in which a histologic pattern of adenocarcinoma mixed with transitional cell carcinoma developed subsequently. Suggestions are made regarding the pathogenesis and diagnosis.

Free full thickness skin graft urethroplasty: current technique.

We present details of our current techniques for skin graft urethroplasty. We believe that careful attention to the details of these operative techniques is important to their success. The changes from our previous reports include: 1) preparation of patch grafts with rounded ends, 2) preparation of tube grafts with fishmouth spatulation, 3) fixation of the stent catheter to the anterior abdominal wall, 4) leaving a stent catheter inlying for 2 weeks and replacing with a smaller catheter if a voiding cystourethrogram shows extravasation, 5) fixation of the graft during preparation by dermatome adhesive, 6) irrigation of the wound with irrigant before closure and 7) urodynamic flow study for non-invasive postoperative followup.

Saralasin test as a diagnostic and prognostic aid in renovascular hypertensive patients subjected to renal operation.

A positive saralasin test in patients with angiographic evidence of renovascular disease and other positive functional tests gives further assurance that these patients will achieve normal or substantially reduced blood pressure postoperatively. In our experience with proved renovascular hypertension there was a 19% incidence of falsely negative saralasin tests. Therefore, saralasin should not be used as the sole screening test in hypertensive patients suspected of having surgically correctable lesions. There is a direct correlation between elevated renin activity and a positive saralasin test. In some patients saralasin may be more sensitive than any other currently used test to detect overactivity of the renin-angiotensin system. This would determine those patients with technical errors in renin sampling and assays. Of the 16 patients (all normotensive) who had 6-month followup tests 5 had elevated peripheral renin activity, probably owing to furosemide stimulation. Of these 5 patients 2 had a positive postoperative saralasin test, raising the question of potential falsely positive responses in cases of essential hypertension and coincidental non-functional renal artery stenosis. Patients with high renin essential hypertension may respond to saralasin, even in the absence of renal artery lesions. A saralasin test should be done in a hospital where all specific conditions can be met and potential complications handled promptly.