Literature survey

About: Literature survey is a research topic. Over the lifetime, 15372 publications have been published within this topic receiving 459196 citations.

Low-dose alcohol effects on human behavior and performance

Abstract: This literature survey reviews the effects of alcohol on human behavior and performance, especially low alcohol dose effects. This review consisted of 155 empirical studies dating from 1985 to mid-1993, using the alcohol effect schema of Kruger. Several general conclusions that were largely in agreement with previous reviews on this topic were reached. First, sensitivity to the subjective intoxicating effects of alcohol was greater than that for all other performance classes and appeared to display a "threshold" with respect to blood alcohol concentration (BAC), rather than the linear relation evident in performance data. Second, sensitivity to performance impairment in "controlled" performance and simulator tasks was greater than that for psychophysical function or "automatic" performance. Finally, a variety of task-, subject-, and environmental-characteristics or conditions were found to mediate the magnitude and sensitivity to alcohol effects, particularly at lower doses. This review concluded that since alcohol sensitivity can vary from time to time, person to person, and situation to situation, the setting of a "safe" BAC will always be arbitrary, being based on a low, but non-zero, incidence of effects below that level.

Effect of hyperbaric oxygen therapy in comparison to conventional or placebo therapy or no treatment in idiopathic sudden hearing loss, acoustic trauma, noise-induced hearing loss and tinnitus. A literature survey.

Abstract: With the published clinical data to hand on the therapeutic results of patients with idiopathic sudden hearing loss, acoustic trauma or noise-induced hearing loss, it may be confirmed that 65% of those polypragmatically treated patients demonstrated a hearing improvement of 19 +/- 4 dB In 35% of the cases, no hearing improvement was detected independent of the drugs administered This corresponds to the results obtained from placebo-treated patients who demonstrated a hearing improvement of 20 +/- 2 dB in 61% of cases and no hearing gain in 39% of cases (fig 1) A different set of results was obtained from patients with a hearing loss who were treated either with prednisolone or placebo The percentage of patients who achieved normal hearing again in the placebo-treated group amounted to 31% and 38% and in the verum-treated group 50% and 78% It may be concluded that a placebo therapy is equally effective to that of all nonsteroidal drugs Problems arise when comparing non-treated patients since information on spontaneous remission rates differs greatly in the references, ie between 25-68% for spontaneous full remissions and 47-89% for spontaneous partial remissions From a statistical view, 35% and 39% of patients experienced no success with nonsteroidal drugs or placebo, respectively These patients can still be helped with HBO therapy 18 patients only underwent primary HBO therapy In all other 50 studies evaluated here with a total of 4, 109 patients suffering from idiopathic sudden hearing loss, acoustic trauma or noise-induced hearing loss and/or tinnitus, HBO therapy was administered as a secondary therapy, ie following unsuccessful conventional therapy If the onset of affliction was more than 2 weeks but no longer than 6 weeks, one half of the cases showed a marked hearing gain (in at least 3 frequencies of more than 20 dB), one-third showed a moderate improvement (10-20 dB) and 13% showed no hearing improvement at all (fig 2) 4% no longer experienced tinnitus, 813% observed an intensity decrease and 12% an intensity increase of their tinnitus condition 135% remained unchanged (fig 2) If HBO therapy was administered at a later stage, but still within 3 months following onset of affliction, 13% showed a definite improvement in hearing, 25% a moderate improvement and 62% no improvement at all 7% no longer suffered from tinnitus, 44% reported an intensity decrease, a similar percentage noticed no change and 5% a temporary deterioration of their tinnitus condition If the onset of affliction was longer than 3 months up to several years, no hearing improvement can be expected in the majority of patients (fig 3); however, one third of the cases reported an intensity decrease of tinnitus, 60-62% reported no change and 4-7% noticed a temporary intensity increase (fig 4) In conclusion, it may be deduced that HBO therapy is recommended and warranted in those patients with idiopathic sudden deafness, acoustic trauma or noise-induced hearing loss within 3 months after onset of disorder

State-of-the-art of surface integrity in machining of metal matrix composites

Abstract: Metal matrix composites (MMCs), as advanced substitutes of monolithic metallic materials, are currently getting an increasing trend of research focus as well as industrial applications for demanding applications such as aerospace, nuclear and automotive because of their enhanced mechanical properties and relative lightweight. Nevertheless, machining of MMC materials remains a challenging task as a result of their structural heterogeneity which leads to deterioration of the machined surface integrity and rapid tool wear. While most of the research was focused on testing and analytical/numerical investigations of the tool wear, limited work was focused on machined surface integrity of MMCs. This paper presents a detailed literature survey on the conventional and non-conventional machining of metal matrix composites with the primary focus on the aspects related to workpiece surface integrity. The contribution of material mechanical and microstructural properties as well as the material removal mechanism upon the quality of workpiece surfaces/subsurface are discussed along with their influences on the fatigue performance of machined part.

Organolead compounds: environmental health aspects.

Abstract: Since 1923 organolead compounds have been used as antiknock additives to gasoline, and few organic chemicals are now produced in greater amounts than organolead. Early cases of poisoning resulted in increased safety precautions, but augmented production and pollution have not been followed by adequate regulations in order to eliminate environmental health hazards. Occupational and environmental exposures to inorganic lead is currently under debate, and the lead standards have recently been lowered in several countries. Organolead compounds are considered much more toxic than the inorganic lead compounds. Recent cases of organolead poisonings, and the discovery of organolead compounds present in brains of people, have questioned the safety of organolead as a gasoline additive. As a result the authors were asked by the Swedish Environmental Protestion Agency to prepare a literature survey on organic lead in 1977. The present review is an updated and extended version of the 1977 survey.