Intermetallics with sp-d orbital hybridisation: morphologies, stabilities and work functions of In-Pd particles at the nanoscale.

The field of intermetallic catalysts, alloying a p-block and a transition metal to form a pM-TM bimetallic alloy, is experiencing robust growth, emerging as a vibrant frontier in catalysis research. Although such materials are increasingly used in the form of nanoparticles, a precise description of their atomic arrangements at the nanoscale remains scarce. Based on the In-Pd binary as a typical pM-TM system, we performed density functional theory calculations to investigate the morphologies, relative stabilities and electronic properties of 24 Å and 36 Å nanoparticles built from the InPd, InPd and InPd compounds.

Composition-dependent chemical ordering predicted in Pt-Ag nanoalloys.

Pt-Ag nanoalloys display an astonishing chemical organization depending on their size and composition. Reversed size-dependent stabilization of ordered nanophases [J. Pirart , , 2019, , 1982-1989] has recently been shown around equiconcentration.

Melting properties of AgPt nanoparticles.

At the nanoscale, materials exhibit unique properties that differ greatly from those of the bulk state. In the case of AgPt nanoalloys, we aimed to study the solid-liquid transition of nanoparticles of different sizes and compositions. This system is particularly interesting since Pt has a high melting point (2041 K compared to 1035 K for Ag) which could keep the nanoparticle solid during different catalytic reactions at relatively high temperatures, such as we need in the growth of nanotubes.

Stress effect on segregation and ordering in Pt-Ag nanoalloys.

We performed a theoretical study of the chemical ordering and surface segregation of Pt-Ag nanoalloys in the range of size from 976 to 9879 atoms (3.12 to 6.76 nm).

Reversed size-dependent stabilization of ordered nanophases.

The size increase of a nanoscale material is commonly associated with the increased stability of its ordered phases. Here we give a counterexample to this trend by considering the formation of the defect-free L1 ordered phase in AgPt nanoparticles, and showing that it is better stabilized in small nanoparticles (up to 2.5 nm) than in larger ones, in which the ordered phase breaks in multiple domains or is interrupted by faults.

Idiopathic nasal bone osteitis: A preliminary report on a recently recognized entity.

Osteitis of the nasal bones is a rare disease; when it occurs, it usually has a known etiology. To the best of our knowledge, idiopathic nasal bone osteitis (NBO) has not been described before. We conducted a study to analyze the behavior of idiopathic NBO and its outcome and to determine a cutoff level for diagnosis using technetium-99m-methylene-diphosphonate (Tc-MDP) bone scanning.

Reevaluation of routine invasive strategy versus noninvasive testing following uncomplicated ST-elevation myocardial infarction.

Background And Aims: While current guidelines recommend a selective invasive approach after low-risk ST-elevation myocardial infarction (STEMI) treated by thrombolysis, based on noninvasive identification of patients with residual or inducible myocardial ischemia, in many instances physicians employ a strategy of routine angiography. The present study was undertaken to reexamine the correlation between noninvasive testing and coronary angiography in patients recovering from uncomplicated STEMI with regard to detection and management of residual infarct artery stenosis and to identify patients with multivessel (MVD) or high-risk coronary disease.

Methods: We prospectively performed predischarge exercise testing (ETT) and myocardial perfusion scintigraphy (MPS) prior to routine predischarge coronary angiography in 83/276 consecutive STEMI patients, who after treatment with initial and early thrombolysis, were defined as low risk by ACC/AHA risk classification.

Myocardial stunning demonstrated with rest and post-stress measurements of left ventricular function using dual-isotope gated myocardial perfusion SPECT.

Objectives: We have evaluated left ventricular ejection fraction (LVEF) at rest (REF) and after stress (SEF) with dual-isotope gated myocardial perfusion SPECT (GMPS) with 201Tl injected at rest and 99mTc sestamibi (99mTc-MIBI) injected at peak stress, to assess the occurrence of post-stress stunning.

Methods: Two hundred and thirty-six consecutive patients had GMPS at rest and post-stress. The summed stress and rest scores and the summed difference score (SDS) were calculated using a 17-segment model analysis of GMPS.

Myocardial perfusion abnormalities early (12-24 h) after coronary stenting or balloon angioplasty: implications regarding pathophysiology and late clinical outcome.

Objective: We prospectively examined the prevalence of reversible perfusion defects on very early (12-24 h) thallium-201 single photon emission computed tomography (SPECT) scintigraphy after angiographically successful percutaneous coronary intervention (PCI) by stenting and/or stand-alone balloon angioplasty and the predictive value of these defects for late target lesion revascularization (TLR).

Patients And Methods: 83 consecutive patients undergoing PCI for 88 lesions (38 balloon angioplasties, 50 stents) underwent very early (12-24 h) SPECT thallium-201 scintigraphy at rest and following administration of 0.7 mg/kg intravenous dipyridamole after PCI.

Gastric emptying time and gastric motility in patients with Parkinson's disease.

Gastrointestinal symptoms such as nausea, abdominal pain, and bloating are frequent complaints of patients with Parkinson's disease (PD). It has been postulated that impaired gastrointestinal function may contribute to the development of motor fluctuations such as delay on and no on in patients with PD. Gastrointestinal impaired function and symptoms may be associated with the disease itself or secondary to levodopa treatment.

Kidney function after radical nephrectomy: assessment by quantitative SPECT of 99mTc-DMSA uptake by the kidneys.

Unlabelled: To determine the function of the remaining contralateral kidney after the removal of a functioning kidney, 30 consecutive patients (18 men, 12 women; average age, 67 y; age range, 34-87 y) who were undergoing unilateral radical nephrectomy were evaluated by sequential quantitative 99mTc-dimercaptosuccinic acid (DMSA) SPECT (QDMSA) studies.

Methods: The 30 patients were undergoing radical nephrectomy for renal tumors. The first study was done before surgery.

Effects of exposure to low concentrations of carbon monoxide on exercise performance and myocardial perfusion in young healthy men.

Objective: To assess the effects of exposure to low concentrations of carbon monoxide (CO), as commonly measured in atmospheric urban air pollution and certain occupational environments, on exercise performance and myocardial perfusion in young healthy men, and the possible need for tighter restrictions on ambient concentrations of CO.

Methods: 15 young, healthy non-smoking men, 18-35 years old, were exposed blindly and randomly to air or to a mixture of CO and air, followed by an exercise treadmill test with thallium heart scintigraphy. Blood was drawn for determination of carboxyhaemoglobin before and at the end of the exposure, and for lactic and pyruvic acid at the beginning and the end of the exercise test.

Importance of immediate and very early postprocedural angiographic and thallium-201 single photon emission computed tomographic perfusion measurements in predicting late results after coronary intervention.

We examined prospectively the hypothesis that the adequacy of initial dilatation may be a major determinant of the late result of coronary angioplasty and that a better assessment of initial dilatation can be made from a combined angiographic and perfusion study than from angiography alone. Angiographic and perfusion (thallium-201 single-photon-emission computed tomography) measurements were made very early (18 to 24 hours) after coronary angioplasty in 59 patients (67 lesions) and also immediately (37 +/- 16 minutes) after the procedures in 19 of them (23 lesions). The early measurements, singly, in combination, and as a restenosis index (restenosis index = thallium-201 ischemic score (units) - minimal luminal area (squared millimeters) were examined as predictors of the late angiographic result.

Semiquantitative skull planar and SPECT bone scintigraphy in diabetic patients: differentiation of necrotizing (malignant) external otitis from severe external otitis.

Unlabelled: Early diagnosis of necrotizing external otitis (NEO) includes the use of bone scintigraphy since clinical assessment alone cannot differentiate the necrotizing type of otitis from the severe type of external otitis in which there is no extension to the adjacent bone. Four-hour planar bone scintigraphy may reflect soft-tissue infection, and therefore may not be useful in distinguishing NEO from severe external otitis (SEO). Twenty-four-hour bone scintigraphy using planar or SPECT imaging may better reflect bone uptake and increase the accuracy of the test.

Imaging patterns of vascular lesions of the head and neck demonstrated by Tc-99m labeled red blood cells.

The authors report on three patients with head and neck masses who demonstrated different imaging patterns on Tc-99m RBC scintigraphy, suggesting different vascular pathology of the lesions. Defining these patterns can be helpful in the diagnosis and decision making concerning the appropriate treatment of these patients.

Quantitative bone and 67Ga scintigraphy in the differentiation of necrotizing external otitis from severe external otitis.

Qualitative technetium Tc 99m bone scintigraphy using phosphate compounds and gallium 67 scintigraphy were described as a helpful means in diagnosing necrotizing external otitis (NEO). They were, however, claimed to be nonspecific. Quantitative Tc 99m methylene diphosphonate bone scintigraphy and gallium 67 scintigraphy were performed in eight patients with NEO and in 20 patients with severe external otitis, in order to prove usefulness of scintigraphy in the diagnosis of NEO.

Effect of nisoldipine on exercise performance in heart failure following myocardial infarction.

The effects of the second generation calcium channel blocking drug nisoldipine on subjective and objective measurements of exercise performance were studied in 19 patients with moderate to severe heart failure (9 New York Heart Association functional class 2, 9 class 3 and 1 class 4) due to fixed ventricular dysfunction following myocardial infarction. Nisoldipine (10 mg 3 times daily) or placebo were administered for 8 weeks in a double-blind parallel study, assessing exercise performance by symptom-limited treadmill exercise testing using a modified Naughton protocol. Nisoldipine was well-tolerated and produced a small increase in peak estimated workload performed (6.

The contribution of perfusion scintigraphy in the evaluation of children suffering from recurrent localized pneumonia.

The value of perfusion scintigraphy as a screening test for children who have suffered from several episodes of recurrent localized pneumonia was evaluated in 32 patients aged 1-15 years. Perfusion studies were carried out using macroaggregated albumin (MAA) labeled with technetium 99m. In 9 patients (28%), large lobar or multisegmental perfusion defects were demonstrated.

A practical SPECT technique for quantitation of drug delivery to human tumors and organ absorbed radiation dose.

A practical quantitative single photon emission computed tomographic (SPECT) technique based on an empirical threshold analysis permits accurate measurements in humans of drug delivery and absorbed radiation dose. The limits of the method have been explored using a wide range of phantom volumes, concentrations, and target-to-nontarget ratios. A threshold of 43% was found to give the best results using volumes of 30 to 3,800 cc.

Gallium 67 scintigraphy in the evaluation of Gardner's syndrome.

Seven patients with Gardner's syndrome--familial polyposis, desmoid tumors, and extracolonic manifestations--underwent gallium 67 (67Ga) scintigraphy. Gallium 67 was taken up by all desmoid tumors and skull osteomas. Three patients were considered clinically disease-free and scintigraphy was normal.

Solitary pericardial metastasis detected by 67Ga scintigraphy in a patient with fever of unknown origin.

67Ga scintigraphy was performed in a patient with fever of unknown origin. Left pneumonectomy had been performed two years previously for carcinoma of the lung. There were no cardiovascular or new pulmonary signs.