Soot morphology: an application of image analysis in high-resolution transmission electron microscopy.

Interest in the fine structure of soots and carbon blacks is motivated by a variety of possible applications. The structure provides information on the origins of the particles and on their adsorptive and reactive properties. This paper describes a method for quantification of the structure of soots and carbon blacks based on direct electron microscopic observation followed by image analysis of these materials. High-resolution transmission electron microscopy (HRTEM) provides a very detailed observation of particle structure. The differences in soot structure, because of its complexity, may not be easily quantifiable with the human eye; therefore, high-level computer software has been used to manipulate HRTEM images. This technique involves the application of fast Fourier transforms (FFT) to single particles and the measurement of characteristic parameters such as interplanar spacings and crystallite sizes from these particles. The methodology and application of this characterization technique are presented here. Results are shown for different samples obtained from soot and carbon black particles selected to illustrate the capabilities of the methodology. Quantitative information can be obtained on structural characteristics, e.g., interplanar spacing, circularity, orientation, elongation, and length distribution of lattice fringes, as well as on the fractional coverage of the extracted pattern.

Characterization by scanning transmission electron microscopy of silica particles from alveolar macrophages of coal miners.

The structure and composition of silica-rich particles recovered by lavage from the lungs of three active miners with different medical histories were studied using high-resolution electron microscopy and chemical microanalysis. The results are compared to the similarly determined structure and composition of respirable-size mineral particles obtained from roof-bolter dust-box samples from two coal mines of widely different bulk quartz concentrations. The results show that the lungs of the miners contain silica-based particles with structures not found in the mine samples. Also, the particle structures and compositions found in the macrophages were different in each of the miners. The results suggest that possibility that intracellular processes may affect the susceptibility of individuals to silica-induced pneumoconioses.

Cardiac arrest due to aberrant left coronary artery originating from the right sinus of Valsalva in a young girl.

We report a 14-year-old girl who sustained a syncope followed by cardiac arrest. She was kept alive for three days by full cardiocirculatory support using left and right ventricular assist devices, but subsequently died in multiple organ failure. Autopsy revealed an anomalous origin of the left coronary artery (LCA) from the right sinus of Valsalva (RSV) and a major left anterior wall infarction. A cyclo-ergometric stress test performed two years before having been negative, we discuss its value in preventing sudden death due to coronary anomalies.

Thrombolytic treatment of pulmonary embolism with APSAC.

BRL 26921 (Eminase registered trade mark in Belgium, Germany and The Netherlands) is the p-anisoyl derivative of the primary (human) lys plasminogen-streptokinase activator complex (APSAC). The acyl-enzyme has the theoretical advantage of causing fibrinolysis in situ in the presence of fibrin clotbound plasminogen. It was administered to 34 patients with severe pulmonary embolism (PE) in an open multicentre study. PE was suspected on clinical, blood gas, ECG, and radiographic data. Pulmonary angiograms performed pre- and post-treatment confirmed the diagnosis and were assessed using the Miller Index (MI). Fibrinogen, plasminogen, alpha-2-antiplasmin, fibrinogen degradation products (FDP), activated partial thromboplastin time (APTT), partial thromboplastin time (PTT) were closely monitored before and after each administration of APSAC. Median angiographic improvement was 50% (range 0-94%). The following adverse events were reported: bleeding at puncture sites (n = 12), haematuria (n = 1), epistaxis (n = 3), fever (n = 2). A blood transfusion was given in one patient with an inguinal haematoma. Systemic fibrinogenolysis occurred in 20/28 patients.

Acute cardiovascular collapse after administration of suxamethonium.

The case is reported of an acute cardiovascular collapse immediately after the administration of suxamethonium to a 25-year-old woman undergoing a diagnostic laparoscopy under general anesthesia. Reintervention 14 days later--without the use of suxamethonium--was uneventful. A skin prik test with suxamethonium proved highly positive. A survey of the literature is given and an attempt is made to distinguish between true anaphylaxis and anaphylactoid reaction.