New quantitative automated model to simulate bacterial dissemination in human tissue during irrigation of contaminated wounds

This study presents a simple and cost-effective model using microparticles to simulate the bacterial distribution pattern in soft tissue after low- and high-pressure irrigation. Silica coated iron microparticles [comparable diameter (1 µm) and weight (0.8333 pg) to Staphylococcus aureus] were applied to the surface of twenty fresh human muscle tissue samples in two amputated lower legs. Particle dissemination into deep tissue layers as an undesired side effect was investigated in four measuring fields as positive control (PC) as well as after performing pulsatile high-pressure (HP, 8 measuring fields) and low-pressure flushing (LP, 8 measuring fields). Five biopsies were taken out of each measuring field to get a total number of 100 biopsies. After histological and digital image processing, the specimens were analysed, and all incomplete sections were excluded. A special detection algorithm was parameterised using the open source bioimage analysis software QuPath. The application of this detection algorithm enabled automated counting and detection of the particles with a sensitivity of 95 % compared to manual counts. Statistical analysis revealed significant differences (p < 0.05) in our three different sample groups: HP (M = 1608, S = 302), LP (M = 2176, SD = 609) and PC (M = 4011, SD = 686). While both HP and LP flushing techniques are able to reduce the number of bacteria, a higher effectiveness is shown for HP irrigation. Nevertheless, a challenge for the validity of the study is the use of dead tissue and therefore a possible negative influence of high-pressure irrigation on tissue healing and further dispersion of particles cannot be evaluated.

Cognition and Perception

Chapter 6 explores the ways culture shapes our cognitive skills and abilities. It discusses cognitive thinking styles, measuring field dependence-independence, holistic and analytic cognition, and applying thinking styles to children’s classroom experiences. It discusses intelligence, intelligence models by Sternberg and Gardner, and culture-specific and cross-cultural studies on intelligence. It also addresses measuring intelligence, culture-specific intelligence tests, factors that shape intelligence such as socioeconomic status and cultural practices, and psychometric tests and cultural fairness. Finally, it explores IQ and social justice; Piaget’s theory; Piaget and culture; problem-solving and culture; and visual perception, including visual illusions and the carpentered world hypothesis. This chapter includes a case study, Culture Across Disciplines box, chapter summary, key terms, a What Do Other Disciplines Do? section, thought-provoking questions, and class and experiential activities.

Modeling of washout of a well-killing liquid after launching of an oil well

The paper presents the results of mathematical modeling of the process of launching and output to the mode of an oil well, which was uploaded by a well-killing liquid at the stage of repairs. After the launching of the electric submergible pump the drop of the bottomhole pressure occurs and the inflow of reservoir fluid begins. As a result the multicomponent mixture is generated inside the well, which consists of oil, associated water, well-killing liquid and free gas, originated from the oil during degassing, and this mixture is pumped out towards wellhead. As soon as the pump characteristics are changed, when the liquid with variable density is pumped out, it is necessary to control the speed of a shaft of the pump for providing the stable pump regime. This problem is solved in the paper for different ratios of densities of well-killing liquid and reservoir fluid by the mathematical modeling of multiphase flow in the well elements and inside the pump. As a mathematical model the one-dimensional quasi-stationary model in approach of drift for description of relative motion of the components is applied, which proved itself well for modeling of non-stationary processes lasting for several days. The comparison of calculated and measuring field parameters is presented. It is shown that the speed of washout of the well-killing liquid from the oil well and the probability of the pump stop due to its head failure depend on the ration of densities of the well-killing liquid and reservoir fluid. It is stated that the monitoring of change of parameters of the pump in time through the mathematical modeling can help to optimize the output to the mode of the well. This allows to avoid stops due to the pump head failure and to diminish the electricity costs.

Dual Resonator MEMS Magnetic Field Gradiometer

Accurate knowledge of the spatial magnetic field distribution is necessary when measuring field gradients. Therefore, a MEMS magnetic field gradiometer is reported, consisting of two identical, but independent laterally oscillating masses on a single chip. The sensor is actuated by Lorentz force and read out by modulation of the light flux passing through stationary and moving arrays of the chip. This optical readout decouples the transducer from the electronic components. Both phase and intensity are recorded which reveals information about the uniformity of the magnetic field. The magnetic flux density is measured simultaneously at two points in space and the field gradient is evaluated locally. The sensor was characterised at ambient pressure by performing frequency and magnitude response measurements with coil and various different permanent magnet arrangements, resulting in a responsivity of 35.67 V/T and detection limit of 3.07 µT/ Hz (@ 83 Hz ENBW). The sensor is compact, offers a large dynamic measurement range and can be of low-cost by using conventional MEMS batch fabrication technology.

Влияние электронного облучения на диэлектрические характеристики монокристаллов AgGaSe-=SUB=-2-=/SUB=-

The effect of various doses of electron irradiation on the dielectric constant and electrical conductivity of triple nonlinear AgGaSe2 crystals at different measuring field frequencies in the temperature range of 100-300 K has been investigated. It has been found that single-crystal irradiation leads to a dielectric constant decrease and an electrical conductivity significant increase. It is shown that the dielectric constant and electrical conductivity increase with an temperature increase. It has been established that AgGaSe2 crystals are characterized by the presence of several conductivity types. A significant frequency dispersion of the dielectric properties of the investigated crystals was found.