Integrated methodology for gas content assessment and prediction in shallow muddy lake sediments: acoustic mapping and correlation analysis.

This paper provides a step-by-step description of integrated methodology for quantification and prediction of gas (methane, CH4) content dynamics in shallow aquatic sediments under changing spatial and temporal conditions. Presence of gas bubbles even in small concentrations significantly affects sediment compressibility, which in turn decreases sound speed in sediment. Our integrated methodology consists of two basic steps. In the first step, free gas content is evaluated by acoustic applications based on the sound speed inferred from the reflection coefficient from gassy bottom. The experimental bottom reflections are registered and compared to the simulated ones, using a geoacoustic inversion technique. The best match between the model and the experiment provides sediment sound speed estimate, which is converted into free gas content using a basic relation. In the second step, a multivariate linear regression is fitted for gas content and closed form expression of gas content dependence on the following predictors, which change spatially and temporally over the aquatic ecosystem, is obtained: 1) water depth, 2) short-leaving CH4 production rate peaks fueled by punctuated organic matter deposition; and 3) CH4 bubble dissolution rates.•Gas content and sound speed in the sediment are estimated via the geoacoustic inversion technique by matching the experimentally recorded and simulated bottom reflections•Only single source and receiver are required for the acoustic methodology•A multivariate linear regression is fitted for gas content to indicate its dependence on various predictors that change spatially and temporally over the lake.

Fluoroscopy is not necessary for Maloney dilation of chronic esophageal strictures.

The use of fluoroscopic guidance for Maloney dilation is controversial. In order to determine if fluoroscopic analysis would enhance the success of dilation and increase recognition of adverse events, we prospectively studied 125 Maloney dilations in 80 patients (mean age, 69.3 years) with mild esophageal strictures. Most strictures (89%) resulted from acid-peptic disease. Operators included two staff physicians (5 and 25 years of experience) and one trainee (1 year of experience). Dilations were performed with the patient seated upright and the operator noting the presence and amount of resistance (dilator size, 36F to 60F; median, 50F). The fluoroscopic monitor was not visible to the operator, and the results were recorded by an observer who did not communicate with the operator. Operator assessment of Maloney dilation was correct in 122 of 125 procedures. Two failures were interpreted as no passage by the operator when passage had occurred as confirmed by fluoroscopy. One failure was interpreted as passage when no passage had occurred as indicated by fluoroscopy. Adverse events included 1 episode of tracheal intubation and failure to recognize the dilator tip curling in the esophagus as observed by fluoroscopy in 6 of 125 (4.8%) procedures. Operator assessment of resistance was more often associated with curling of the dilator on the greater curve of the stomach than with an esophageal stricture. Greater operator experience tended to correlate with increased success and correct interpretation of dilation. Maloney dilations performed with patients at 30 degrees rather than upright at 90 degrees were associated with a marked increase in unsuccessful dilator passage and curling of dilator tip.(ABSTRACT TRUNCATED AT 250 WORDS)

[Immunological reactivity in postinfarct cardiosclerosis]. / Immunologicheskaia reaktivnost' u bol'nykh postinfarktnym kardiosklerozom

In 77 patients with postinfarction cardiosclerosis the blood serum immunoglobulin level was studied along with some indices of the lipid and protein metabolism. An increased blood level of immunoglobulins A, M and G was observed in postinfarction cardiosclerosis cases, those with hyper-beta-lipoproteinemia, hypercholesterolemia and C-reactive protein having a significantly higher level of immunoglobulin G and than the rest of the patients. In those having an increased content of immunoglobulin G in the blood serum hypo-beta-globulinemia was observed, as well as a considerable increase of the gamma-globulin fraction as compared to those having a normal or decreased level of immunoglobulin G. Proceeding from these data the authors suggest the presence of autoimmune shifts in the patients with postinfarction cardiosclerosis that are closely connected with lipid and protein metabolism disorders.

[Catecholamines and other vasoactive substances in blood in cardiogenic shock]. / Katekholaminy i drugie vazoaktivnye veshchestva v krovi pri koronarnom shoke

The blood levels of catecholamines, serotonin, histamine and acetylcholine were studied in 17 patients with severe and moderate coronary shock. The blood level of the above vasoactive substances varied widely, and no clear regularity was noted in the changes of the content of the catecholamines, histamine, serotonin and acetylcholine. A relatively higher (on the average) level of noradrenaline was noted in severe shock, in contrast to the moderate cases, as well as a relatively low level of noradrenaline and acetylcholine in the blood of patients with a full atrioventricular block and bradycardia. In studying the vasoactive substances dynamically similar, phase-like fluctuations of the blood level of histamine and serotonin were noted in some patients. In a few cases similar, often phase-like, changes were also noted in the blood content of noradrenaline and acetylcholine