Management of patent ductus arteriosus in premature infants.

Closure of hemodynamically significant patent ductus arterios (HSPDA)  is one of the most important questions in modern neonatal intensive care, especially for preterm babies. Long-term functioning of the hemodynamically significant  arterial duct leads to a large number of complications in premature babies, such as: bronchopulmonary dysplasia, periventricular leucomalacia, intraventricular hemorrhage, retinopathy of the premature. To prevent all these complications, the PDA should be closed pharmacologically or surgically as soon as possible without any hesitation. COX inhibitors are commonly used nowa days. Ibuprofen and indomethacin show the equal efficacy and no significant adverse events. But some patients still need surgical treatment. The aim of the study was to determine the feasibility, effectiveness and safety of using various volumes of infusion in combination with COX inhibitors and to determine its effect on the timing of the closure of PDA. 91 premature infants with a gestational age of 26-31 weeks with manifestations of respiratory distress syndrome and НSPDA were studied retrospectively. Premies were divided into 2 groups. Research groups were representative as to gestational age, gender, and weight (1205.0±435.0 g). Therapy for PDA closure included the use of various volumes of restrictive or liberal infusion therapy (from 50 to 100 ml/kg/day) and COX inhibitors (indomethacin, ibuprofen). The volume of infusion therapy was limited in the first group. Preemies received 53.5±6.4 ml/kg/day on DOL1 and 2. From the third day urine excretion increased and the volume of infusion therapy also raised to 63.6±5.6 ml/kg/day, and on day 5 – to 89.7±6.8 ml/kg/day. In the second group there was no strict limitation of the volume of infusion therapy (especially in the first 5 days). Delayed period of PDA closure (on average from 14.55±0.56 DOL) was associated with absence of limitation of the infusion volume. In the first group, volume of infusion therapy was restricted in the first 5 days, and the closure of the ductus arteriosus occurred extremely early (on 2.35±0.48 DOL). COX inhibitors were prescribed according to the standard scheme: in the first 3 days indomethacin was administered orally in doses of 0.2/0.1/0.1 mg/kg/day. If the premature baby had symptoms of intestinal paresis ( this restricted oral administration of indomethacin), ibuprofen was prescribed in a three-day course in doses of 10/5/5 mg/kg/day intravenously or 20/10/10 mg/kg/day in rectal form. In all  groups, standard PDA closure therapy was used. In the more remote periods (14 and 28 days), there was no fundamental difference in the volume of infusion in all groups. For early PDA closure limitation of infusion therapy in the first 3-5 days in combination with COX is principle

Spatial and Wavenumber Resolution of Doppler Reflectometry

Doppler reflectometry spatial and wavenumber resolution is analyzed within the framework of the linear Born approximation in slab plasma model. Explicit expression for its signal backscattering spectrum is obtained in terms of wavenumber and frequency spectra of turbulence which is assumed to be radially statistically inhomogeneous. Scattering efficiency for both back and forward scattering (in radial direction) is introduced and shown to be inverse proportional to the square of radial wavenumber of the probing wave at the fluctuation location thus making the spatial resolution of diagnostics sensitive to density profile. It is shown that in case of forward scattering additional localization can be provided by the antenna diagram. It is demonstrated that in case of backscattering the spatial resolution can be better if the turbulence spectrum at high radial wavenumbers is suppressed. The improvement of Doppler reflectometry data localization by probing beam focusing onto the cut-off is proposed and described. The possibility of Doppler reflectometry data interpretation based on the obtained expressions is shown.Comment: http://stacks.iop.org/0741-3335/46/114

Management of patent ductus arteriosus in premature infants

Closure of hemodynamically significant patent ductus arterios (HSPDA) is one of the most important questions in modern neonatal intensive care, especially for preterm babies. Long-term functioning of the hemodynamically significant arterial duct leads to a large number of complications in premature babies, such as: bronchopulmonary dysplasia, periventricular leucomalacia, intraventricular hemorrhage, retinopathy of the premature. To prevent all these complications, the PDA should be closed pharmacologically or surgically as soon as possible without any hesitation. COX inhibitors are commonly used nowa days. Ibuprofen and indomethacin show the equal efficacy and no significant adverse events. But some patients still need surgical treatment. The aim of the study was to determine the feasibility, effectiveness and safety of using various volumes of infusion in combination with COX inhibitors and to determine its effect on the timing of the closure of PDA. 91 premature infants with a gestational age of 26-31 weeks with manifestations of respiratory distress syndrome and НSPDA were studied retrospectively. Premies were divided into 2 groups. Research groups were representative as to gestational age, gender, and weight (1205.0±435.0 g). Therapy for PDA closure included the use of various volumes of restrictive or liberal infusion therapy (from 50 to 100 ml/kg/day) and COX inhibitors (indomethacin, ibuprofen). The volume of infusion therapy was limited in the first group. Preemies received 53.5±6.4 ml/kg/day on DOL1 and 2. From the third day urine excretion increased and the volume of infusion therapy also raised to 63.6±5.6 ml/kg/day, and on day 5 – to 89.7±6.8 ml/kg/day. In the second group there was no strict limitation of the volume of infusion therapy (especially in the first 5 days). Delayed period of PDA closure (on average from 14.55±0.56 DOL) was associated with absence of limitation of the infusion volume. In the first group, volume of infusion therapy was restricted in the first 5 days, and the closure of the ductus arteriosus occurred extremely early (on 2.35±0.48 DOL). COX inhibitors were prescribed according to the standard scheme: in the first 3 days indomethacin was administered orally in doses of 0.2/0.1/0.1 mg/kg/day. If the premature baby had symptoms of intestinal paresis ( this restricted oral administration of indomethacin), ibuprofen was prescribed in a three-day course in doses of 10/5/5 mg/kg/day intravenously or 20/10/10 mg/kg/day in rectal form. In all groups, standard PDA closure therapy was used. In the more remote periods (14 and 28 days), there was no fundamental difference in the volume of infusion in all groups. For early PDA closure limitation of infusion therapy in the first 3-5 days in combination with COX is principle

Evolution and global collapse of trapped Bose condensates under variations of the scattering length

We develop the idea of selectively manipulating the condensate in a trapped Bose-condensed gas, without perturbing the thermal cloud. The idea is based on the possibility to modify the mean field interaction between atoms (scattering length) by nearly resonant incident light or by spatially uniform change of the trapping magnetic field. For the gas in the Thomas-Fermi regime we find analytical scaling solutions for the condensate wavefunction evolving under arbitrary variations of the scattering length $a$. The change of $a$ from positive to negative induces a global collapse of the condensate, and the final stages of the collapse will be governed by intrinsic decay processes.Comment: 4 pages, LaTeX, other comments are at http://WWW.amolf.nl/departments/quantumgassen/TITLE.HTM

Geophysical Observatory in Kamchatka region for monitoring of phenomena connected with seismic activity

Regular monitoring of some geophysical parameters in association with seismicity has been carried out since last year at the Japan-Russian Complex Geophysical Observatory in the Kamchatka region. This observatory was organized in connection with the ISTC project in Russia and was motivated by the results of the FRONTIER/RIKEN and FRONTIER/NASDA research projects in Japan. The main purpose of the observations is to investigate the electromagnetic and acoustic phenomena induced by the lithosphere processes (especially by seismic activity). The seismicity of the Kamchatka area is analyzed and a description of the observatory equipment is presented. At present, the activity of the observatory includes the seismic (frequency range &#x2206;F = 0.5 – 40 Hz) and meteorological recordings, together with seismo-acoustic (&#x2206;F = 30 – 1000 Hz) and electromagnetic observations: three-component magnetic ULF variations ( &#x2206;F = 0.003 – 30 Hz), three-component electric potential variations ( &#x2206;F <u><</u> 1.0 Hz), and VLF transmitter’s signal perturbations ( &#x2206;F ~ 10 – 40 kHz)

Study of electromagnetic emissions associated with seismic activity in Kamchatka region

International audienceA review of data processing of electromagnetic emission observation collected at the Complex Geophysical Observatory Karimshino (Kamchatka peninsula) during the first 5 months (July?November, 2000) of its operation is given. The main goal of this study addresses the detection of the phenomena associated with Kamchatka seismic activity. The following observations have been conducted at CGO: variations of ULF/ELF magnetic field, geoelectric potentials (telluric currents), and VLF signals from navigation radio transmitters. The methods of data processing of these observations are discussed. The examples of the first experimental results are presented

Stabilization of the number of Bose-Einstein condensed atoms in evaporative cooling via three-body recombination loss

The dynamics of evaporative cooling of magnetically trapped $^{87}$Rb atoms is studied on the basis of the quantum kinetic theory of a Bose gas. We carried out the quantitative calculations of the time evolution of conventional evaporative cooling where the frequency of the radio-frequency magnetic field is swept exponentially. This "exponential-sweep cooling" is known to become inefficient at the final stage of the cooling process due to a serious three-body recombination loss. We precisely examine how the growth of a Bose-Einstein condensate depends on the experimental parameters of evaporative cooling, such as the initial number of trapped atoms, the initial temperature, and the bias field of a magnetic trap. It is shown that three-body recombination drastically depletes the trapped $^{87}$Rb atoms as the system approaches the quantum degenerate region and the number of condensed atoms finally becomes insensitive to these experimental parameters. This result indicates that the final number of condensed atoms is well stabilized by a large nonlinear three-body loss against the fluctuations of experimental conditions in evaporative cooling.Comment: 7 pages, REVTeX4, 8 eps figures, Phys. Rev A in pres

Improvement of microstructure and mechanical properties of high dense SiC ceramics manufactured by high-speed hot pressing

Non-oxide ceramics possess high physical-mechanical properties, corrosion and radiation resistance, which can be used as a protective materials for radioactive wastes disposal. The aim of the present study was the manufacturing of high density SiC ceramics with advanced physical and mechanical parameters. The high performance on the properties of produced ceramics was determined by the dense and monolithic structure. The densified silicon carbide samples possessed good mechanical strength, with a high Vickers micro hardness up to 28.5 GPa.Безкисневі керамічні матеріали демонструють високі фізико-механічні властивості, корозійну та радіаційну стійкість, що роблять їх перспективними кандидатами для використання в якості бар'єрних матеріалів для захоронення радіоактивних відходів. Метою цієї роботи було отримання високощільної SiC-кераміки з вдосконаленими фізичними і механічними властивостями. Високі параметри отриманої кераміки визначаються формуванням високощільної і монолітної структури. Кераміка карбіду кремнію має поліпшену механічну міцність і високу твердість по Віккерсу порядка 28,5 ГПa.Бескислородные керамические материалы демонстрируют высокие физико-механические свойства, коррозионную и радиационную стойкость, делающие их перспективными кандидатами для использования в качестве барьерных материалов для захоронения радиоактивных отходов. Целью настоящей работы было получение высокоплотной SiC-керамики с усовершенствованными физическими и механическими свойствами. Высокие параметры полученной керамики определяются формированием высокоплотной и монолитной структуры. Керамика карбида кремния обладает улучшенной механической прочностью и высокой твердостью по Виккерсу порядка 28,5 ГПa

The use of thromboelastography and the functional tests with double local hypoxia of the upper limb to assess the risk of thromboembolism in patients undergoing surgery

Introduction: Prothrombotic is considered a condition that leads to the development of venous or arterial thrombosis and its consequences. There are many factors that cause a violation of the hemostatic potential in patients undergoing surgery with existing risk factors for thromboembolism, a more detailed study of the blood coagulation system, including the study of the compensatory capabilities of the hemocoagulation system, should be conducted. One of these methods is a functional test with double local hypoxia of the upper limb (DLHUL) under the control of thromboelastography (TEG). Goals: The purpose of the study - to identify the degree of thrombotic risk in patients preparing for planned surgical intervention, who belong to the risk group of thrombotic complications, to compare and evaluate the state of the hemostasis system in healthy volunteers and in this cohort of patients using a functional test with double local hypoxia of the upper limb by the method of thromboelastography. Materials and methods: A randomized prospective study was conducted. Patients were divided into two groups depending on the presence of risk factors for thrombosis. Group 1 consisted of healthy volunteers (n = 40) who are not at risk of thrombosis. Group 2 includes patients with existing factors of thrombotic risk (n = 120) who are preparing for scheduled surgical interventions. These patients underwent a functional test of "double local hypoxia of the upper limb" (DLHUL) using thromboelastographic (TEG) methods of studying the hemocoagulation system. The main task of this functional test is to create a trigger component to determine the limits of hemostasis, the origin and duration of adaptive and compensatory reactions of the hemostasis system. Indicators of the hemostasis system are recorded using a thromboelastograph before and after the test. The links of hemostasis are reflected by the following indicators: aggregate state of blood (A0), contact coagulation intensity (CCI), coagulation drive intensity (ICD), maximum clot density - maximum activity (MA), fibrinolytic activity - clot retraction and lysis index (IRCL). The results. Analyzing the data of thromboelastography after performing DLHUL, among the patients of Group 1, two types of reaction of the hemostasis system were found in patients without predictors of thrombotic risk: compensated (n= 20) (characterized by a decrease in the indicators of the vascular-platelet component; subcompensated (n = 20) (characterized by an increase in the indicators of the vascular -platelet component). In subjects of Group 1, TEG indicators indicate an increase in the external mechanism of prothrombinase formation, and the reaction of the procoagulant link of the blood coagulation system in response to the influence of a trigger indicates a change in the directionality of the hemostatic potential towards hypercoagulation. In subjects of group 1 with a compensated type, there is an increase in the components of fibrinolysis and a deviation of the hemostatic potential towards hypocoagulation is observed. The state of the hemostasis system in patients of Group 2 is characterized by pronounced changes in the hemostatic potential in all links. In the vascular-platelet link, a violation of platelet aggregation was noted, with an increase in indicators in response to a stimulus. When conducting the DLHUL test in the subjects of group 2, a decompensated (n = 98) and exhausted (n = 22) type of reaction to the test with local hypoxia of the upper limb was determined. That is, with increased platelet aggregation, hypercoagulation, inhibition of the anticoagulant system and fibrinolysis before the action of the trigger factor, after performing the DLHUL test, these disorders in the hemostasis system progress towards hypercoagulation, which is indicated by the increase in platelet aggregation, the strengthening of the coagulation link of the hemostatic system, the depression of fibrinolysis increases . However, the intensity of these changes is not as high as in patients of group 1 after the DLHUL test. Conclusions: The test with double local hypoxia of the upper limb is effective as a trigger factor to determine the compensatory capabilities of the HS. Depending on the type of reaction of the platelet-vascular, coagulation components of hemostasis and fibrinolysis to the influence of the trigger, two types of reaction of the blood aggregate state regulation system are possible in people who do not have an anamnesis of factors provoking a hypercoagulable state: compensated and subcompensated. Therefore, when planning surgical intervention in this cohort of patients, the risk of thrombotic complications is low. Depending on the type of reaction of the platelet-vascular, coagulation components of hemostasis and fibrinolysis to the influence of the trigger, two types of reaction of the blood aggregate state regulation system are possible in people with an anamnesis of factors provoking a hypercoagulable state: decompensated (more often) and depleted (less often). Patients with a history of factors provoking a hypercoagulable state have a high risk of perioperative thrombotic complications and a possible risk of thrombo-hemorrhagic complications, including the syndrome of disseminated intravascular coagulation. Changes in all links of the hemostasis system in response to the DLHUL test indicate the need to use anticoagulant therapy in patients with an anamnesis of factors provoking a hypercoagulable state as one of the components of preoperative preparation