Possibilities of assessment of reliability of an anthropotechnical system

"Reliability and safety characteristics [7] of an anthropotechnical system are the basic information about the correctness of relation between a man (e.g. pilot) and a helicopter (machine). Methods of defining them are still an open problem. The article presents an innovative way of definition of reliability characteristics of a pilot and a helicopter engine as well as an entire anthropotechnical system. Described are theoretical bases of this method, which are various configurations of the ""equation of state"" describing relations pilot – helicopter and helicopter – pilot [8, 9]. Defined was the set of ""numbers of limit state violations"" of the parameter of pilot’s physical condition aP and technical state of the helicopter aS, which as ""premises of damage"" were used for calculation of estimators of reliability characteristics. It is noteworthy that these characteristics could be particularly useful in the process of comparing different pilots and helicopters in various situations appearing in the course of utilisation

Possibilities of assessment of reliability of an anthropotechnical system

"Reliability and safety characteristics [7] of an anthropotechnical system are the basic information about the correctness of relation between a man (e.g. pilot) and a helicopter (machine). Methods of defining them are still an open problem. The article presents an innovative way of definition of reliability characteristics of a pilot and a helicopter engine as well as an entire anthropotechnical system. Described are theoretical bases of this method, which are various configurations of the ""equation of state"" describing relations pilot – helicopter and helicopter – pilot [8, 9]. Defined was the set of ""numbers of limit state violations"" of the parameter of pilot’s physical condition aP and technical state of the helicopter aS, which as ""premises of damage"" were used for calculation of estimators of reliability characteristics. It is noteworthy that these characteristics could be particularly useful in the process of comparing different pilots and helicopters in various situations appearing in the course of utilisation

Key principle of the efficient running, swimming, and flying

Empirical observations indicate striking similarities among locomotion in terrestrial animals, birds, and fish, but unifying physical grounds are lacking. When applied to efficient locomotion, the analytical mechanics principle of minimum action yields two patterns of mechanical similarity via two explicit spatiotemporal coherent states. In steady locomotory modes, the slow muscles determining maximal optimum speeds maintain universal intrinsic muscular pressure. Otherwise, maximal speeds are due to constant mass-dependent stiffness of fast muscles generating a uniform force field, exceeding gravitation. Being coherent in displacements, velocities and forces, the body appendages of animals are tuned to natural propagation frequency through the state-dependent elastic muscle moduli. Key words: variational principle of minimum action (04.20.Fy), locomotion (87.19.ru), biomechanics (87.85.G-).Comment: Submitted to the Europhysical Letter

A rigid barrier between the heart and sternum protects the heart and lungs against rupture during negative pressure wound therapy

<p>Abstract</p> <p>Objectives</p> <p>Right ventricular heart rupture is a devastating complication associated with negative pressure wound therapy (NPWT) in cardiac surgery. The use of a rigid barrier has been suggested to offer protection against this lethal complication, by preventing the heart from being drawn up and damaged by the sharp edges of the sternum. The aim of the present study was to investigate whether a rigid barrier protects the heart and lungs against injury during NPWT.</p> <p>Methods</p> <p>Sixteen pigs underwent median sternotomy followed by NPWT at -120 mmHg for 24 hours, in the absence (eight pigs) or presence (eight pigs) of a rigid plastic disc between the heart and the sternal edges. The macroscopic appearance of the heart and lungs was inspected after 12 and 24 hours of NPWT.</p> <p>Results</p> <p>After 24 hours of NPWT at -120 mmHg the area of epicardial petechial bleeding was 11.90 ± 1.10 cm²when no protective disc was used, and 1.15 ± 0.19 cm²when using the disc (p < 0.001). Heart rupture was observed in three of the eight animals treated with NPWT without the disc. Lung rupture was observed in two of the animals, and lung contusion and emphysema were seen in all animals treated with NPWT without the rigid disc. No injury to the heart or lungs was observed in the group of animals treated with NPWT using the rigid disc.</p> <p>Conclusion</p> <p>Inserting a rigid barrier between the heart and the sternum edges offers protection against heart rupture and lung injury during NPWT.</p

Effects of Curcuma longa (turmeric) on postprandial plasma glucose and insulin in healthy subjects

<p>Abstract</p> <p>Background</p> <p>Previous animal studies have shown that <it>Curcuma (C.) longa </it>lowers plasma glucose. <it>C. longa </it>may thus be a promising ingredient in functional foods aimed at preventing type 2 diabetes. The purpose of the study is to study the effect of <it>C. longa </it>on postprandial plasma glucose, insulin levels and glycemic index (GI) in healthy subjects.</p> <p>Methods</p> <p>Fourteen healthy subjects were assessed in a crossover trial. A standard 75 g oral glucose tolerance test (OGTT) was administered together with capsules containing a placebo or <it>C. longa</it>. Finger-prick capillary and venous blood samples were collected before, and 15, 30, 45, 60, 90, and 120 min after the start of the OGTT to measure the glucose and insulin levels, respectively.</p> <p>Results</p> <p>The ingestion of 6 g <it>C. longa </it>had no significant effect on the glucose response. The change in insulin was significantly higher 30 min (<it>P </it>= 0.03) and 60 min (<it>P </it>= 0.041) after the OGTT including <it>C. longa</it>. The insulin AUCs were also significantly higher after the ingestion of <it>C. longa</it>, 15 (<it>P </it>= 0.048), 30 (<it>P </it>= 0.035), 90 (<it>P </it>= 0.03), and 120 (<it>P </it>= 0.02) minutes after the OGTT.</p> <p>Conclusions</p> <p>The ingestion of 6 g <it>C. longa </it>increased postprandial serum insulin levels, but did not seem to affect plasma glucose levels or GI, in healthy subjects. The results indicate that <it>C. longa </it>may have an effect on insulin secretion.</p> <p>Trial registration number</p> <p>NCT01029327</p

Quantum Averaging I: Poincar\'e--von Zeipel is Rayleigh--Schr\"odinger

An exact analogue of the method of averaging in classical mechanics is constructed for self--adjoint operators. It is shown to be completely equivalent to the usual Rayleigh--Schr\"odinger perturbation theory but gives the sums over intermediate states in closed form expressions. The anharmonic oscillator and the Henon--Heiles system are treated as examples to illustrate the quantum averaging method.Comment: 12 pages, LaTeX, to appear in Journ. Phys.

A genomic biomarker signature can predict skin sensitizers using a cell-based in vitro alternative to animal tests

<p>Abstract</p> <p>Background</p> <p>Allergic contact dermatitis is an inflammatory skin disease that affects a significant proportion of the population. This disease is caused by an adverse immune response towards chemical haptens, and leads to a substantial economic burden for society. Current test of sensitizing chemicals rely on animal experimentation. New legislations on the registration and use of chemicals within pharmaceutical and cosmetic industries have stimulated significant research efforts to develop alternative, human cell-based assays for the prediction of sensitization. The aim is to replace animal experiments with in vitro tests displaying a higher predictive power.</p> <p>Results</p> <p>We have developed a novel cell-based assay for the prediction of sensitizing chemicals. By analyzing the transcriptome of the human cell line MUTZ-3 after 24 h stimulation, using 20 different sensitizing chemicals, 20 non-sensitizing chemicals and vehicle controls, we have identified a biomarker signature of 200 genes with potent discriminatory ability. Using a Support Vector Machine for supervised classification, the prediction performance of the assay revealed an area under the ROC curve of 0.98. In addition, categorizing the chemicals according to the LLNA assay, this gene signature could also predict sensitizing potency. The identified markers are involved in biological pathways with immunological relevant functions, which can shed light on the process of human sensitization.</p> <p>Conclusions</p> <p>A gene signature predicting sensitization, using a human cell line in vitro, has been identified. This simple and robust cell-based assay has the potential to completely replace or drastically reduce the utilization of test systems based on experimental animals. Being based on human biology, the assay is proposed to be more accurate for predicting sensitization in humans, than the traditional animal-based tests.</p