Velocity map imaging of inelastic and elastic low energy electron scattering in organic nanoparticles.

Electron transport is of fundamental importance and has application in a variety of fields. Different scattering mechanisms affect electron transport in the condensed phase; hence, it is important to comprehensively understand these mechanisms and their scattering cross sections to predict electron transport properties. Whereas electron transport is well understood for high kinetic energy (KE) electrons, there is a discrepancy in the experimental and theoretical values for the Inelastic Mean Free Path (IMFP) in the low KE regime. In this work, velocity map imaging soft X-ray photoelectron spectroscopy is applied to unsupported organic nanoparticles (squalene) to extract experimental values of inelastic and elastic mean free paths (EMFPs). The obtained data are used to calculate corresponding scattering cross sections. The data demonstrate a decrease in the IMFP and increase in the EMFP with increasing electron KE between 10 and 50 eV.

Soft X-ray spectroscopy of nanoparticles by velocity map imaging.

Velocity map imaging (VMI), a technique traditionally used to study chemical dynamics in the gas phase, is applied here to study X-ray photoemission from aerosol nanoparticles. Soft X-rays from the Advanced Light Source synchrotron, probe a beam of nanoparticles, and the resulting photoelectrons are velocity mapped to obtain their kinetic energy distributions. A new design of the VMI spectrometer is described. The spectrometer is benchmarked by measuring vacuum ultraviolet photoemission from gas phase xenon and squalene nanoparticles followed by measurements using soft X-rays. It is demonstrated that the photoelectron distribution from X-ray irradiated squalene nanoparticles is dominated by secondary electrons. By scanning the photon energies and measuring the intensities of these secondary electrons, a near edge X-ray absorption fine structure (NEXAFS) spectrum is obtained. The NEXAFS technique is used to obtain spectra of aqueous nanoparticles at the oxygen K edge. By varying the position of the aqueous nanoparticle beam relative to the incident X-ray beam, evidence is presented such that the VMI technique allows for NEXAFS spectroscopy of water in different physical states. Finally, we discuss the possibility of applying VMI methods to probe liquids and solids via X-ray spectroscopy.

Primary angioplasty for the treatment of acute myocardial infarction: experience at two community hospitals without cardiac surgery.

OBJECTIVES: We sought to establish the safety and efficacy of primary percutaneous transluminal coronary angioplasty in patients with acute myocardial infarction (AMI) at two community hospitals without on-site cardiac surgery. BACKGROUND: Though randomized studies indicate that primary angioplasty in AMI may result in superior outcomes compared with fibrinolytic therapy, the performance of primary angioplasty at hospitals without cardiac surgery is debated. METHODS: Three experienced operators performed 506 consecutive immediate coronary angiograms with primary angioplasty when appropriate in patients with suspected AMI at two community hospitals without cardiac surgery, following established rigorous program criteria. RESULTS: Clinical high risk predictors (Killip class 3 or 4, age > or = 75 years, anterior AMI, out-of-hospital ventricular fibrillation) and/or angiographic high risk predictors (left main or three-vessel disease or ejection fraction <45%) were present in 69.6%. Angioplasty was performed in 66.2%, with a median time from emergency department presentation to first angiogram of 94 min and a procedural success rate of 94.3%. The in-hospital mortality for the entire study population was 5.3%. Of those without initial cardiogenic shock, the in-hospital mortality was 3.0%. Of 300 patients who were discharged after primary angioplasty, only four died within the first 6 months, with 97.7% follow-up. No patient died or needed emergent aortocoronary bypass surgery because of new myocardial jeopardy caused by a complication of the cardiac catheterization or angioplasty procedure. CONCLUSIONS: Immediate coronary angiography with primary angioplasty when appropriate in patients with AMI can be performed safely and effectively in community hospitals without on-site cardiac surgery when rigorous program criteria are established.

Primary cutaneous cryptococcosis.

Cryptococcal infections in immuno-compromised patients are of major importance. Current opinion holds that cutaneous cryptococcal infections in these patients indicate disseminated disease. In our renal transplant patient with primary cutaneous cryptococcosis, intravenously administered antifungal chemotherapy resulted in resolution of the disease and appears to have prevented disseminated infection.

Variability of the lupus band test. Results in 18 patients with systemic lupus erythematosus.

Six simultaneous skin biopsies were performed on each of 18 patients with systemic lupus erythematosus. Variability was found both in the lupus band test (LBT) findings and in the presence of its individual immunoglobulin components and C3 in adjacent biopsy specimens taken from both sun-exposed and sun-protected sites. This variability in immune deposits is a major factor in the lack of reproducible association between LBT findings and clinical and serologic indicators of disease activity.

Disseminated candidiasis. Newer approaches to early recognition and treatment.

The clinical triad of fever, erythematous papular rash, and diffuse muscle tenderness has recently been reported to be presumptive evidence for disseminated candidiasis in the immunocompromised host who is receiving broad-spectrum antibiotics. This case report further explores this clinical association and demonstrates that the immediate institution of antifungal therapy before laboratory test results are known may favorably alter the outcome of this frequently fatal condition. In view of the low positive yield of blood cultures, skin biopsy may represent an effective method for achieving rapid laboratory confirmation of the diagnosis.

Malignant acanthosis nigricans: a review.

Malignant acanthosis nigricans is a dermatosis that appears grossly as a hyperpigmented, velvety, or verrucous hyperplasia of the epidermis, most marked in flexural areas. It is always associated with a malignancy. In 277 cases reviewed, the condition was associated with gastric carcinomas in 55.5%, with other intra-abdominal carcinomas in 17.7%, and with malignancies in other sites in 26.8%. Current theories for the association and pathogenesis of the cutaneous process are discussed.

Acanthosis nigricans and the sign of Leser-Trélat associated with adenocarcinoma of the gallbladder.

A case of adenocarcinoma of the gallbladder associated with acanthosis nigricans and the sign of Leser-Trélat is presented. The significant underrepresentation of adenocarcinoma of the gallbladder in association with malignant acanthosis nigricans is noted. If malignant acanthosis nigricans is caused by an ectopic peptide, a relative lack of production of the postulated substance by gallbladder adenocarcinoma cells could account for this finding.