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At least 73 records · Page 4Linked to original sources
PubMed1990

A case of tumour simulating pulp space infection.

General practitioners and accident and emergency departments are often involved in the management of hand or finger sepsis. Such cases are usually easily diagnosed and treated. We report a more serious disorder which may mimic the condition and cause diagnostic confusion.

Aged↗
PubMed1997

Accuracy of radiographic diagnosis of peri-implant radiolucencies--an in vitro experiment.

The absence of a peri-implant radiolucency on radiographs is used as a criterion for implant success. The purpose of the present study was to evaluate the accuracy of diagnosing peri-implant radiolucencies using an experimental model. Astra Tech fixtures were inserted into 20 bony specimens. Later, the fixtures were removed and the prepared cavities were enlarged in 2 steps. The specimens were radiographed under strictly standardized circumstances in the 3 stages ("press-fit" = simulated osseointegration, and "0.1 mm space" and "0.175 mm space" = simulated connective tissue layer). All specimens were radiographed with 2 vertical angulations (0 degree and 15 degrees). Ten observers read the radiographs and evaluated bone-implant relationship on a 5-point scale. The interobserver agreement was low. Specificity was remarkably low, and sensitivity was moderate. A significant difference in diagnostic accuracy was found for 0.175 mm peri-implant-space compared to 0.1 mm space. The diagnostic accuracy was found to be highest for 0.175 mm peri-implant space specimens. It is concluded, that radiography seems to be an unreliable method for diagnosing peri-implant spaces, although accuracy improved at increasing space widths. Strict orthogonal projection angles did not improve diagnostic accuracy.

Alveolar Bone Loss↗
PubMed1997

Content analysis of the crew communication with external communicants under prolonged isolation.

BACKGROUND: The communication between space crews and outside monitoring personnel in Mission Control gives us valuable information about crewmember psychological health. Studying the formal parameters of similar communication during ground-based space simulation missions helps us understand the psychological climate of confined groups over time, and this information can be applied to long-term space missions. HYPOTHESES: We hypothesized that psychological closing and information filtration will be observed in a confined crew as the mission progresses and will differ by the type of communication (e.g., audio vs. computer-generated) with the outside monitors in the simulated Mission Control (MC). In addition, communication patterns will vary with the specific group of people on-duty outside. METHOD: Audio and computer communications between space simulation crews and MC teams were analyzed during two isolation studies lasting 135 and 90 d at the Institute for Biomedical Problems in Moscow. A number of temporal, content and quantitative parameters of verbal activity were examined. RESULTS: The total intensity of communication dropped after month 1 of the missions. The Commander had the highest intensity of communication. There was evidence for the presence of psychological closing and information filtration in the crews over time, with some variation based on type of communication. Communication patterns differed with different outside teams. CONCLUSIONS: The communication between confined groups and outside monitoring personnel is affected by psychological closing and information filtration and by the make-up of the teams that comprise the monitoring groups.

Adult↗
PubMed2001

Mid- and far-infrared spectroscopic studies of the influence of temperature, ultraviolet photolysis and ion irradiation on cosmic-type ices.

Infrared (IR) studies of laboratory ices can provide information on the evolution of cosmic-type ices as a function of different simulated space environments involving thermal, ultraviolet (UV), or ion processing. Laboratory radiation experiments can lead to the formation of complex organic molecules. However, because of our lack of knowledge about UV photon and ion fluxes, and exposure lifetimes, it is not certain how well our simulations represent space conditions. Appropriate laboratory experiments are also limited by the absence of knowledge about the composition, density, and temperature of ices in different regions of space. Our current understanding of expected doses due to UV photons and cosmic rays is summarized here, along with an inventory of condensed-phase molecules identified on outer solar system surfaces, comets and interstellar grains. Far-IR spectra of thermally cycled H2O are discussed since these results reflect the dramatic difference between the amorphous and crystalline phases of H2O ice, the most dominant condensed-phase molecule in cosmic ices. A comparison of mid-IR spectra of products in proton-irradiated and UV-photolyzed ices shows that few differences are observed for these two forms of processing for the simple binary mixtures studied to date. IR identification of radiation products and experiments to determine production rates of new molecules in ices during processing are discussed. A new technique for measuring intrinsic IR band strengths of several unstable molecules is presented. An example of our laboratory results applied to Europa observations is included.

Carbonic Acid↗
PubMed1996

Hormonal, water balance, and electrolyte changes during sixty-day confinement.

The EXEMSI experiment has made it clear that it is difficult to perform psychological and physiological protocols satisfactorily in the same study. It is, therefore, essential that the objectives of study be defined clearly before the start. While behavioral and psychological studies may be possible and provide valid results for a small group of mixed gender, it is more difficult to conduct valid physiological studies due to large differences between individuals and even in the same individual over time. As stated before, it is unusual in space research on humans and even during space simulation studies to have large and homogeneous groups of subjects. The consequence is that the results remain tentative. For a better understanding of the physiological data collected during the ISEMSI ad EXEMSI experiments, they should be correlated with the results of the psychological studies. One of the conclusions drawn from the ISEMSI experiment was that confinement provides a valuable parallel to other simulations of weightlessness, such as bedrest. The same pattern of changes in parameters like the blood volume regulating hormones renin and aldosterone was observed as in bedrest. After the EXEMSI study we can say that the conditions imposed by confinement, high work load, and stress, potentiate these effects. This implies that in using head-down bedrest as a weightlessness simulation the confinement effects must be identified by setting adequate control conditions for the head-down position, for short-term as well as for long-term simulations. Indeed, we have seen in the two isolation studies that confinement may have its effects at the beginning of the isolation period (EXEMSI) as well as during the entire isolation period (ISEMSI). In planning for EXEMSI we wanted to obtain more insight in some of the phenomena observed during ISEMSI by the introduction of new techniques such as the doubly labeled water method for determination of total body water. However, in some cases the opposite effects of those encountered in ISEMSI were found. This was probably due to the many changes in the experimental scenario, like number of subjects, mixed gender, living space per subject, and workload. Thus, for future isolation studies the operational scenario should be better examined and preferably standardized. Nevertheless, in such studies as well as in long-term sojourns in a space station, the crew size will not be larger than that of the EXEMSI crew. Physiologists will, therefore, have to become familiar with the study of small groups of subjects and to try to overcome the problems of large individual differences and statistical analysis of data from small groups.

Adult↗
PubMed1997

An investigation into the placement of force delivery systems and the initial forces applied by clinicians during space closure.

This in vitro investigation was designed to establish not only how clinicians apply forces for space closure when using the straight wire appliance and sliding mechanics, but also to quantify the initial force levels produced. A single typodont, with residual extraction space in each quadrant, was set up to simulate space closure using sliding mechanics. On two occasions, at least 2 months apart, 18 clinicians were asked to apply three force delivery systems to the typodont, in the manner in which they would apply it in a clinical situation. The three types of force delivery system investigated were elastomeric chain, an elastomeric module on a steel ligature, and a nickel-titanium closed coil spring. A choice of spaced or unspaced elastomeric chain produced by a single manufacturer was provided. The amount of stretch which was placed on each type of system was measured and, using an Instron Universal Testing Machine, the initial force which would be generated by each force delivery system was established. Clinicians were assessed to examine their consistency in the amount of stretch which each placed on the force delivery systems, their initial force application and their ability to apply equivalent forces with the different types of force delivery system. The clinicians were found to be consistent in their method of application of the force delivery systems and, therefore, their force application, as individuals, but there was a wide range of forces applied as a group. However, most clinicians applied very different forces when using different force delivery systems. When using the module on a ligature the greatest force was applied, whilst the nickel titanium coil springs provided the least force.

Dental Alloys↗
PubMedDate not supplied

[Biological value of proteins in food rations of crews on Saliut orbital stations].

The biological value of the protein component of three modifications of the Salyut space diet was measured in laboratory studies and in simulated space flights. Three experimental runs of up to 68 days in duration were carried out on 20 volunteers. During the study the following parameters of protein metabolism were measured: total protein and protein fractions in serum; urea, uric acid and creatinine in blood; total nitrogen, urea, ammonia, uric acid and creatinine in urine. The results obtained showed that the diet modifications provided an adequate nutritional status and a normal level of the above parameters of protein metabolism.

Amino Acids↗
PubMedDate not supplied

Rational combinatorial library design. 1. Focus-2D: a new approach to the design of targeted combinatorial chemical libraries.

We describe a new computational approach, called Focus-2D, to the rational design of targeted combinatorial chemical libraries. This approach is based on the hypothesis that structurally similar compounds display similar biological activity profiles. Building blocks that are used in a combinatorial chemical synthesis are randomly assembled to produce virtual library compounds. Individual library compounds are represented by Kier-Hall topological descriptors. Molecular similarities between compounds are evaluated quantitatively by modified pairwise Euclidean distances in multidimensional descriptor space. Simulated annealing is used to search the potentially large structural space of virtual chemical libraries to identify compounds similar to lead molecules. Frequency analysis of building block composition of selected virtual compounds identifies building blocks that can be used in combinatorial synthesis of chemical libraries with high similarity to the lead molecules. We show that this method correctly identifies building found in active peptoids with adrenergic or opioid activities.

Drug Design↗
PubMed1994

Intrapleural omentum simulating pleural effusion.

We report herein a case of Morgagni hernia of omentum into the pleural space, simulating a pleural effusion on a routine chest radiograph. A 62-year-old man was referred to our clinic for close examination of a pleural effusion-like shadow at the right costophrenic region. He had no history of trauma and no symptoms. Chest computed tomographic scan showed a pleural effusion-like shadow with a fat density. Thoracoscopy revealed a movable omentum-like mass and no significant fluid in the right pleural space. Magnetic resonance imaging and celiac angiography confirmed the herniation of omentum into the right pleural space. This case suggests that a Morgagni hernia must be excluded in a patient with a fat density effusion-like shadow in the pleural space.

Diagnosis, Differential↗
PubMed1987

Psychological and interpersonal issues in space.

As future manned space missions become longer, and as crews become more heterogeneous, psychological and interpersonal factors will take on increasing importance in assuring mission success. On the basis of a review of more than 60 American and Soviet space simulation studies on Earth, along with reports from U.S. and Soviet space missions, the author identifies nine psychological and seven interpersonal issues, which are discussed along with pertinent research findings and examples from manned spaceflights. He concludes that more psychological and interpersonal research should be done under actual spaceflight conditions and offers suggestions.

Adaptation, Psychological↗
PubMed1978

Radiobiological experiment aboard the biosatellite Cosmos-690.

In 1974, the USSR launched the biosatellite Cosmos-690 equipped with a gamma-irradiation unit that carried 35 rats. On the 10th flight day, the rats were exposed to radiation at doses of 220 or 800 rads. During the subsequent 10 d, radiation injury developed in a space environment. Similar ground-based experiments were carried out to simulate space flight environment effects. The results obtained were studied on a comparative basis. The conclusion is made that effects of a short-term space flight, as long as 20 d, do not essentially modify the radiobiological effect.

Animals↗
PubMed1998

[The study of biocide effectiveness of ultraviolet treatment in media stimulating space station environment].

An experiment was performed to study the biocide effect of ultraviolet treatment of simulated space station milieu. UV generated by low and moderately power-intensive sources (from 10 W to 1 kW) showed a good promise for decontaminating, within the reach, solid structural materials, and the air and water in the cabin. For instance, within 10 minutes of the UV-treatment aerial bacteria in 20 m3 were reduced in 12 to 30 times while fungal microflora was fully suppressed. Water containing spores and vegetative cells of both pathogenic and nonpathogenic microorganisms became essentially sterile after 4 to 10 minutes of treatment with low UV (in the order of 0.01 W/cm2). Different UV modalities can lay the basis for development of specific technologies of microbial decontamination of various spacecraft.

Decontamination↗