Assessment of fluid balance in different regimens of infusion therapy of high surgical risk patients with acute abdominal pathology.

Fluid disorders always accompany acute pathology of abdominal organs. To conduct comparative analysis of efficiency of the goal-directed and restrictive regimens of infusion therapy of replenishment of volume depletion in high surgical risk patients with acute abdominal pathology 80 patients, operated by urgent laparotomy were studied. Patients were divided into two groups. In the first group (n=40) a goal-directed infusion therapy was conducted, in the second (n=40) – restrictive. Rheographic method was used to investigate the performance of water sectors of the organism, daily and cumulative water balances were defined, the percentage of excessive fluid was determined and estimated. In patients of the first group an increase in plasma volume by 11% (p<0.05), exceeding of the volume of interstitium by 14% (p<0.05) and the volume of extracellular fluid by 7% (p<0.05) on the 1st and 2nd day were noted. From the 3 to 7th day a reduction in extracellular fluid to 91.5% (p<0.05) of the norm was noted. Recovery of all the studied parameters was detected on the 10th postoperative day, when the percent of excessive fluid reached 9.6%. In patients of the second group there was restoration of plasma volume to normal in reduced by 10% (p<0.05) – 12% (p<0.05) from the norm of the interstitium volume, respectively to the 1st and 2nd day after surgery. From the 3d day there was a significant restoration to normal of all the studied parameters, which coincided with the “zero” values of the daily water balance and sufe limits of the percent of excess fluid, which reached 6.1% on the 10th day of treatment. Thus, the goal-directed infusion therapy allows to perform the correction of volume depletion in high surgical risk patients with acute abdominal pathology by increasing intravascular volume to excessive and increase of interstitium volume on 1st and 2nd day, development of a mild volume depletion from the 3d to 5th day, maintainance of the percentage of excessive fluids within safe borders. Restrictive mode of infusion therapy normalizes fluid balance of water sectors due to restoration of plasma volume in 6 hours of treatment and maintains it within the limits of the norm during all the postoperative period, preventis the development of interstitial oedema, ensures the "zero" daily water balance and limits the postoperative growth of the percentage of excess fluid.

Peculiarities of britlle and ductile materials destruction and deformation during the explosion of industrial shaped charges

Purpose. To study the laws of deformation and destruction of brittle and ductile rocks and concretes under explosion of industrial shaped charges. Methods. In experiments, the following methods of investigation were used: method of contact sensors for determination of jet velocity; determination of the ultrasonic wave velocity in the concrete samples; methods of optical and electronic microscopy; X-ray phase analysis; measuring and visual analysis of the dimensions and nature of deformation and destruction zones. Findings. The work describes the experimental data on the destruction of barriers made of concrete, granite, steel ST 3, AMC-n alloy, and zinc by the explosions of shaped charges of serial production with porous liners. Calculation formulas for estimating the radius of a destruction zone of geomaterials and rocks in case of a semi-infinite barrier are suggested. The calculation method is based on the estimation of energy impact on the rock by jet penetration velocity into the barrier. Jet velocities are determined experimentally and by engineering methods. The reasons for deviations in the hole shape and deflection of the destruction zone from the symmetry axis were determined. Originality. The modes of penetration of shaped jets into rocks of different porosity, the size of the fracture zone around the hole and the causes and mechanisms of the deviations of the hole shape from the symmetric one are established. Practical implications. The results of the research will be used to design blasting-and-perforation operations in geotechnological wells and can be used to design initiating devices for borehole charges.Мета. Дослідження закономірностей деформування й руйнування крихких і пластичних гірських порід та бетонів при вибуху промислових кумулятивних зарядів. Методика. Метод контактних датчиків для визначення швидкості струменя; визначення швидкості ультразвукових хвиль у зразках бетону; оптична та електронна мікроскопія; рентгенофазний аналіз; вимірювання й візуальний аналіз розмірів та характеру зон деформування і руйнування. Результати. В роботі описані експериментальні дані про деформацію та руйнування перешкод з бетону, граніту, пінобетону, сталі Ст 3, сплаву АМЦ-н і цинку вибухами кумулятивних зарядів серійного виробництва з пористим облицюванням. Запропоновано розрахункові формули для оцінки радіусу зони руйнування геоматеріалів і гірських порід у разі напівнескінченної перешкоди. Визначено причини відхилень форми отвору і зони руйнування від осі симетрії. Наукова новизна. Визначено режими проникнення кумулятивних струменів у породи різної пористості, розміри зони руйнування навколо отвору, а також причини і механізми відхилення форми отвору від симетричної. Практична значимість. Результати досліджень будуть використані для проектування вибухо-прострілочних робіт у геотехнологічних свердловинах і можуть бути використані для конструювання ініціюючих пристроїв свердловинних зарядів.Цель. Исследование закономерностей деформирования и разрушения хрупких и пластичных горных пород и бетонов при взрыве промышленных кумулятивных зарядов. Методика. Метод контактных датчиков для определения скорости струи; определение скорости ультразвуковых волн в образцах бетона; оптическая и электронная микроскопия; рентгенофазный анализ; измерение и визуальный анализ размеров и характера зон деформирования и разрушения. Результаты. В работе описаны экспериментальные данные о деформировании и разрушении преград из бетона, гранита, пенобетона, стали Ст 3, сплава АМЦ-н и цинка взрывами кумулятивных зарядов серийного производства с пористыми облицовками. Предложены расчетные формулы для оценки радиуса зоны разрушения геоматериалов и горных пород в случае полубесконечной преграды. Определены причины отклонений формы отверстия и зоны разрушения от оси симметрии. Научная новизна. Определены режимы проникания кумулятивных струй в породы различной пористости, размеры зоны разрушения вокруг отверстия, а также причины и механизмы отклонения формы отверстия от симметричной. Практическая значимость. Результаты исследований будут использованы для проектирования взрыво-прострелочных работ в геотехнологических скважинах и могут быть использованы для конструирования инициирующих устройств скважинных зарядов.The authors extend their sincere gratitude to the staff of Scientific Research Centre “Materialoobrobka vybukhom” (Processing Materials by Explosion) of the Paton Institute of Electric Welding affiliated with the National Academy of Sciences of Ukraine for the assistance in organization and conducting of the research. We would like to express special thanks to S.I. Kochetkov for the provided data on the velocity of longitudinal sound in solid sandy rocks, and to V.P. Bugaits for the assistance in experiments

Thermal switching of indirect interlayer exchange in magnetic multilayers

We propose a magnetic multilayer layout, in which the indirect exchange coupling (IEC also known as RKKY) can be switched on and off by a slight change in temperature. We demonstrate such on/off IEC switching in a Fe/Cr/FeCr-based system and obtain thermal switching widths as small as 10--20~K, essentially in any desired temperature range, including at or just above room temperature. These results add a new dimension of tunable thermal control to IEC in magnetic nanostructures, highly technological in terms of available materials and operating physical regimes.Comment: 3 figures, Supplementary Inf

Modern aspects of the volemic management of patients with acute abdominal pathology.

In conditions of urgent surgical care, the age of patients, concomitant somatic chronic pathology are factors that significantly increase the risk of postoperative complications and lethality.  The latter in this group of patients is 30-80% and is associated with the development of hypovolemia.  Treatment of the latter is traditionally provided by the routine conduct of a liberal regimen of infusion therapy (IT) to achieve hypervolemic hemodilution by infusion of crystalloid and colloidal drugs.  It was found that the consequences of the liberal regime of IT is the development of acute hypervolemia.  The accumulation of excess fluid forms the development of interstitial edema of tissues, causing a decrease in tissue oxygenation, the development of coagulation disorders and multi-organ dysfunction ̸ inadequacy, inhibits the healing of wounds.  Therefore, in recent years, a restrictive (restricted) IT regimen has become available for clinical use, the goal of which is to achieve normovolemia.  At the same time, evidence-based clinical studies indicate the possibility of using perioperative optimization of hemodynamics in the clinic by individualizing IT in accordance with the indices of central hemodynamics

Modern aspects of the volemic management of patients with acute abdominal pathology.

In conditions of urgent surgical care, the age of patients, concomitant somatic chronic pathology are factors that significantly increase the risk of postoperative complications and lethality.  The latter in this group of patients is 30-80% and is associated with the development of hypovolemia.  Treatment of the latter is traditionally provided by the routine conduct of a liberal regimen of infusion therapy (IT) to achieve hypervolemic hemodilution by infusion of crystalloid and colloidal drugs.  It was found that the consequences of the liberal regime of IT is the development of acute hypervolemia.  The accumulation of excess fluid forms the development of interstitial edema of tissues, causing a decrease in tissue oxygenation, the development of coagulation disorders and multi-organ dysfunction ̸ inadequacy, inhibits the healing of wounds.  Therefore, in recent years, a restrictive (restricted) IT regimen has become available for clinical use, the goal of which is to achieve normovolemia.  At the same time, evidence-based clinical studies indicate the possibility of using perioperative optimization of hemodynamics in the clinic by individualizing IT in accordance with the indices of central hemodynamics

Perioperative water balance in patients with acute abdominal pathology in a liberal regime of infusion therapy.

In order to evaluate the effectiveness of the liberal regime of infusion therapy, we examined 50 patients with acute abdominal pathology considering the state of the water sectors of the body. We established that liberal regime of infusion causes hypervolemia and hyperhydration of peripheral tissues during the first 6 hours of the perioperative period, it retains a moderate deficit of hypovolemia and dehydratation from 1 to 14 day of observation and forms an increase in interstanial volume, causing its maximum edema from the 3d to 7th day of observation. These changes are combined with positive daily and cumulative water balances, which is reflected in a critical increase in the percentage of excess fluid from the 5th day of postoperative period

Dynamic characteristics of a mobile robot manipulator built on the basis of a mechanism with parallel kinematic couplings

The mathematical model of dynamical characteristics of a mobile robot with parallel kinematic bonds is developed on the basis of the use of the theory of fuzzy sets. For the dynamic system platform, four partial dynamic subsystems are introduced. Three of them describe the translational movement of the platform in three directions, and the subsystem of the spherical motion describes the rotary motion of the platform relative to the pole. Dynamic subsystems of a variable-length rod take into account the distribution of the parameters of the rod in length. The mathematical modeling of dynamic processes in mobile works of parallel kinematics at single and packet pulse dynamic shock disturbances is carried out.Розроблена математична модель динамічних характеристик мобільного робота з паралельними кінематичними зв’язками на основі використання теорії нечітких множин. Для динамічної системи платформи введено чотири парціальні динамічні підсистеми. Три з них описують поступальні переміщення платформи у трьох напрямках, а підсистема сферичного руху описує поворотний рух платформи відносно полюса. Динамічні підсистеми штанг змінної довжини враховують розподіленість параметрів штанг по довжині. Проведено математичне моделювання динамічних процесів мобільного роботах паралельної кінематики при одиничних і пакетних імпульсних динамічних збуреннях штанг

Ferromagnetic resonance and interlayer exchange coupling in magnetic multilayers with compositional gradients

Ferromagnetic resonance (FMR) in magnetic multilayers of type F1/f/F2, where two strongly ferromagnetic layers F1 and F2 are separated by a weakly magnetic spacer f with a compositional gradient along its thickness, is investigated. The method allows to detect the weak signal from the spacer in additional to the more pronounced and readily measured signal from the outer strongly-magnetic layers, and thereby study the properties of the spacer as well as the interlayer exchange interaction it mediates. Variable temperature FMR measurements, especially near the relevant Curie points, reveal a rich set of properties of the exchange interactions in the system. The obtained results are useful for designing and optimizing nanostructures with thermally-controlled magnetic properties.Comment: 6 pages, 3 figure