Добірка наукової літератури з теми "Induction-dynamic transducer"

A displacement sensor with controlled measuring force and its characteristics analysis are discussed in this paper. The displacement sensor consists of an electric induction transducer with high resolution and a voice coil motor (VCM). The measuring principles, structure of the sensor are discussed. Theory model, dynamic and static characteristics of VCM are analysed. A measuring system for surface topography with large measuring range is constructed based on the displacement sensor and 2D moving platform. Measuring force of the sensor in measurement process of surface topography can be controlled at μN level and hardly changes. It has been used in measurement of bearing ball，bullet mark, etc.

Dynamic modeling and stability domain analysis of a system consisting of a synchronous generator sup-plying an induction motor load through a series compensated weak network has been carried out in this paper. The impact of X/Rratio of the feeder and generation control system parameters on the stability domain with respect to series compensation has been examined through eigenvalue calculations and time domain simulations. From the studies conducted, it was observed that the stability domain of the system with respect to series compensation depends on the grid strength in addition to the excitation system parameters. Eigenvalue analysis shows that there is a strong correlation between the exciter gain, time constants of the measurement transducer and exciter, and the series compensation level. The main contribution of this work is to reveal new bifurcations which arise in these systems which has been studied through eigenvalue analysis and time domain simulations for various combinations of system parameters.

Injection of myelin basic protein (MBP)-pulsed dendritic cells (DC) into healthy rats, as we reported before and observed in this study, did not induce clinical experimental allergic encephalomyelitis (EAE), but effectively protected the rats from subsequent EAE induction. The mechanisms by which MBP-pulsed DC mediate immune protection are not completely understood. In the present study, we mainly explored the dynamic change of cytokine and growth factor mRNA expression in spinal cords after subcutaneous injection of MBP-pulsed and unpulsed DC. The expression of interleukin (IL)-1, interferon-g and tumour necrosis factor-a as well as programmed death ligand (PDL)-1, PDL-2, signal transducer and activator of transcription (STAT)4, STAT6, matrix metalloproteinase (MMP)-9 and tissue inhibitor of metalloproteinases (TIMP)-2 was increased on day 0 postimmunization (p.i.). The increase of IL-12 expression was observed on day 7 p.i., while the increase of IL-10 expression mainly occurred on day 14 p.i. Except downregulation of insulin-like growth factor-1, the expression of brain-derived neurotrophic factor, ciliary neurotrophic factor, fibroblast growth factor (FGF)-2 and platelet-derived growth factor (PDGF)-B/C as well as nerve growth factor receptor (NGF-R), FGF receptor, PDGF-R-a and b was elevated on day 0 p.i., while the increase of TIMP and NGF was observed on days 0 and 7 p.i. There were no significant differences on MMP-2, spinal cord-derived growth factor and PDGF-A mRNA expression. In line with the suppression of EAE induced by MBP-pulsed DC, the dynamic change of cytokines and growth factors in spinal cords should constitute a beneficial microenvironment against EAE.

The current state of technology is characterized by the mass use of electricity, the use of various electrical, electronic and radio devices. This causes expansion of magnetic measurements and the need to develop new highly sensitive measuring equipment for a wide range of frequencies. One of its main elements, that largely determines the accuracy, frequency and dynamic ranges, are the primary measuring sensors of strength (induction) of alternating magnetic fields. Many works have been devoted to the analysis and development of various sensors of strength (induction) of magnetic fields. At the same time, it can be noted the lack of a systematic approach to the measurement of alternating magnetic fields. The problem of the general classification of methods of measurement of alternating magnetic fields and, accordingly, primary measuring sensors of strength (induction) of alternating magnetic fields is not solved. In most cases, separate issues of measuring alternating magnetic fields and certain types of sensors are considered. That does not allow obtaining a holistic picture in this area and make the right choice of direction for solving assigned tasks. The comprehensive analysis of methods of measuring alternating magnetic fields was carried out in this work. Based on it, the classification of primary measuring sensors of strength (induction) of alternating magnetic fields, on the physical principles of transformation was proposed. Accordingly, the available measuring sensors of alternating magnetic fields following to the group of used physical phenomena can be divided into: magnetomechanical, induction, galvanomagnetic, quantum, magneto-optical and photomagnetic. Depending on the characteristics of each of these phenomena, separate measurement methods and types of measuring sensors were highlighted. The current state of development of each of the types of measuring sensors of strength of alternating magnetic fields was analyzed, their advantages and disadvantages were determined, the limits of dynamic and frequency ranges, the maximum values of errors were outlined. The obtained results allow to significantly simplify and reduce the time of choosing the necessary method of strength (induction) of alternating magnetic fields measuring and to choose the necessary type of measuring sensor to effectively solve the tasks.

Abstract Ligand-responsive allosteric transcription factors (aTF) play a vital role in genetic circuits and high-throughput screening because they transduce biochemical signals into gene expression changes. Programmable control of gene expression from aTF-regulated promoter is important because different downstream effector genes function optimally at different expression levels. However, tuning gene expression of native promoters is difficult due to complex layers of homeostatic regulation encoded within them. We engineered synthetic promoters de novo by embedding operator sites with varying affinities and radically reshaped binding preferences within a minimal, constitutive Escherichia coli promoter. Multiplexed cell-based screening of promoters for three TetR-like aTFs generated with this approach gave rich diversity of gene expression levels, dynamic ranges and ligand sensitivities and were 50- to 100-fold more active over their respective native promoters. Machine learning on our dataset revealed that relative position of the core motif and bases flanking the core motif play an important role in modulating induction response. Our generalized approach yields customizable and programmable aTF-regulated promoters for engineering cellular pathways and enables the discovery of new small molecule biosensors.

Abstract Tumor-Associated Antigen Presentation by γδ T-Cells in Cancer Immunotherapy Human γδ T-cells are considered to represent a link between innate and adaptive immunity. Their innate killing properties display a potent cytotoxic activity against solid tumors as well as lymphoid and myeloid malignancies. Subsequently, by lysing affected target cells and liberating antigen for uptake, they can differentiate into professional antigen presenting cells (pAPCs) for induction of CD4+ and CD8+ T cell responses. The degree of antigen-specific stimulation of responder T cells is increased in the presence of antibody(Ab)-assisted opsonized target cells, involving the low-affinity receptor for IgG CD16 (Fc γRIII), equivalent to that seen with mature antigen-loaded DCs. To elaborate the implications of this combined killing and pAPC function we have studied how freshly isolated as well as expanded and cloned populations of γδ T-cell subsets kill a target tumor cell, and take up and cross-present tumor-associated antigens (TAA). We performed quantitative analysis on the cellular uptake of different sizes of microspheres, analyzing the correlation between opsonization and internalization. All γδ T-cell subtypes were expanded using artificial APC, engineered to express CD86, CD137L and IL-15, and anti- γδ TCR Ab (B1). Short (EAAGIGILTV) and long (GHSYTTAEEAAGIGILTVILGVLLL) MART-1 peptides were used as antigens for γδ T-cell presentation to MART-1 TCR-transduced cytotoxic T-cells. A CFSE assay was performed to assess cytotoxic T-cell proliferation. Target cells and polysterene microspheres were opsonized with human anti-CD20 IgG1, Rituximab (RTX). CD16 function was blocked with a mouse monoclonal IgG1 anti-CD16 blocking Ab (clone LNK16). Imaging flowcytometry allowed us to quantify internalization of FITC-labeled microspheres. The Internalization Score is defined as the ratio of intensity inside the cell to the intensity of the entire cell. Both γδ T-cell lines and expanded γδ T-cell clones cultured long-term, remarkably, retain both tumor cell killing and take up tumor cell lysates or long synthetic TAA peptides and cross-present these on MHC class I to CD8+ cytotoxic T-cells in a dynamic, controllable fashion, dependent on Ab-opsonization. (Figure 1). The Ab-opsonization of 1 µm microspheres correlates with a higher receptor-mediated phagocytic uptake, in a CD16 dependent manner (Figure 2). The opsonization of 0,5 µm microspheres led to clumping of the microspheres, accounting for the lower uptake in this particular subgroup. For a lack of better alternative, moDCs have been widely used in experimental immunotherapy settings. The ease of manipulation of human γδ T-cells, the ability to be expanded ex-vivo combined with antigen presentation makes them a great potential tool for immunotherapy as a complementary or integrative strategy. Ligation of the γδ T-cell receptor at the tumor site will activate their expansion and innate killing. Yet, antigen presentation will only occur after binding of an immunoglobulin to the tumor cell, thereby activating their dual role. Our goal is to define an effective adjuvant vaccine formulation for inducing leukemia-specific cytolytic effects. We are currently investigating whether γδ T-cells can directly present and/or cross-present to cytotoxic T-cells in-vivo in a humanized mouse model. We believe that the uptake of microspheres by γδ T-cells has an impact on the development of vaccination strategies for cancer immunotherapy, as the immunization of γδ T-cells is a powerful method for the induction or reactivation of cytotoxic T cell specific responses. FIGURE 1 CFSE assay of γδ T-cell lines cross-presenting short and long MART-1 peptides to MART-1 TCR-transduced cytotoxic T-cells in a dynamic, controllable fashion, dependent on Ab-opsonization FIGURE 1. CFSE assay of γδ T-cell lines cross-presenting short and long MART-1 peptides to MART-1 TCR-transduced cytotoxic T-cells in a dynamic, controllable fashion, dependent on Ab-opsonization FIGURE 2a FIGURE 2a. FIGURE 2b FIGURE 2b. Disclosures No relevant conflicts of interest to declare.

Abstract Interleukin-12 (IL-12) is a heterodimeric cytokine mediating a dynamic interplay between T cells and antigen-presenting cells (APCs). Preclinical studies have demonstrated that recombinant murine IL-12 (rmIL-12) promotes specific antitumor immunity mediated by T cells in several types of tumors. However, the in vivo antitumor properties of IL-12 in acute myeloid leukemia (AML) have not been previously reported. We show here in a murine AML model that systemic administration of rmIL-12 significantly delays tumor growth but is incapable of rescuing mice from lethal leukemia. In contrast, AML cells genetically modified to express IL-12 (IL12-AML) using murine stem cell virus (MSCV) p40 + p35 elicit very potent antileukemic activity. Vaccines with lethally irradiated IL12-AML cells protect naive mice against challenge with wild-type AML cells and, more importantly, can cure mice bearing a considerable leukemic burden. Immunized mice show no signs of systemic IL-12 toxicity and their spleen histology is comparable with naive mice spleen. In vivo depletion of IL-12, interferon-γ (IFN-γ), or CD8+ T cells after injections with live IL12-AML cells abrogates completely the antileukemia immune responses. Studies on the in vitro effects of IFN-γ on AML cells demonstrate enhanced expression of major histocompatibility complex (MHC) and accessory molecules and induction of the costimulatory molecules B7.1 and B7.2, but no significant direct antiproliferative effect. 51Cr release assays show that rejection of live IL12-AML cells supports the development of long-lasting leukemia-specific cytotoxic T lymphocyte (CTL) activity. In conclusion, our results demonstrate that IL12-AML vaccination is a safe and potent immunotherapeutic approach that has a great potential to eliminate minimal residual disease in patients with AML.

Interleukin-12 (IL-12) is a heterodimeric cytokine mediating a dynamic interplay between T cells and antigen-presenting cells (APCs). Preclinical studies have demonstrated that recombinant murine IL-12 (rmIL-12) promotes specific antitumor immunity mediated by T cells in several types of tumors. However, the in vivo antitumor properties of IL-12 in acute myeloid leukemia (AML) have not been previously reported. We show here in a murine AML model that systemic administration of rmIL-12 significantly delays tumor growth but is incapable of rescuing mice from lethal leukemia. In contrast, AML cells genetically modified to express IL-12 (IL12-AML) using murine stem cell virus (MSCV) p40 + p35 elicit very potent antileukemic activity. Vaccines with lethally irradiated IL12-AML cells protect naive mice against challenge with wild-type AML cells and, more importantly, can cure mice bearing a considerable leukemic burden. Immunized mice show no signs of systemic IL-12 toxicity and their spleen histology is comparable with naive mice spleen. In vivo depletion of IL-12, interferon-γ (IFN-γ), or CD8+ T cells after injections with live IL12-AML cells abrogates completely the antileukemia immune responses. Studies on the in vitro effects of IFN-γ on AML cells demonstrate enhanced expression of major histocompatibility complex (MHC) and accessory molecules and induction of the costimulatory molecules B7.1 and B7.2, but no significant direct antiproliferative effect. 51Cr release assays show that rejection of live IL12-AML cells supports the development of long-lasting leukemia-specific cytotoxic T lymphocyte (CTL) activity. In conclusion, our results demonstrate that IL12-AML vaccination is a safe and potent immunotherapeutic approach that has a great potential to eliminate minimal residual disease in patients with AML.

Abstract Patients with MDS and a complex karyotype have a very short median survival and a high risk of transformation into AML. We showed earlier that TP53 mutations are associated with complex karyotype and disease progression. However, it is poorly understood how TP53 mutations contribute to the induction of chromosomal instability in hematopoietic stem and progenitor cells. We therefore established a long-term cell culture (LTC) model and investigated the role of TP53 in human CD34+ hematopoietic stem and progenitor cells (HSCs) isolated from cord blood and in HT1080 cells over 6 weeks. We chose 3 different modifications: 1) TP53-deficient HSCs via shRNA knockdown, 2) HSCs with different lentivirally introduced TP53 hotspot mutations (R248W, R175H, R273H, R249S) and 3) HT1080 cells with different lentivirally introduced TP53 hotspot mutations (R248W, R175H, R273H, R249S). We performed each LTC at least three times. In order to stress the cells and induce chromosomal instability, we irradiated half of the cells. Besides functional assays in the first week, we performed detailed cytogenetic analysis including telomere length measurement at weeks 1, 3 and 6. TP53 mutations and the downregulation of TP53 led to impaired hematopoiesis with decreased erythroid differentiation, increased apoptosis and decreased proliferation. None of the modifications induced chromosomal instability in cells without irradiation. In the irradiated cells, all cells carrying a TP53 mutation or a TP53 downregulation developed a chromosomal instability in comparison to the cells transduced with control vectors. However, no stable complex clones developed. Telomeres shortened during follow-up in HSCs carrying the mutations R175H, R248W and R249S. No other cells showed a dynamic response in telomere length. In order to analyze the DNA repair capacity, we performed yH2AX foci assay. Surprisingly, the same cells which showed a telomere shortening showed a lower amount of foci. This could be due to a lower amount of double-strand breaks or to a lower ability to form foci. In summary, TP53 mutations and the downregulation of TP53 led to an increased chromosomal instability in irradiated cells only. Modifications alone did not lead to the development of complex karyotypes. Furthermore, only the mutations R175H, R248W and R249S led to a telomere shortening. In conclusion, a TP53 mutation seems to require additional passenger mutations in order to lead to MDS or AML with complex karyotype. Disclosures No relevant conflicts of interest to declare.

Mitochondrial respiration is responsible for more than 90% of oxygen consumption in humans. Cells utilize oxygen as the final electron acceptor in the aerobic metabolism of glucose to generate ATP which fuels most active cellular processes. Consequently, a drop in tissue oxygen levels to the point where oxygen demand exceeds supply (termed hypoxia) leads rapidly to metabolic crisis and represents a severe threat to ongoing physiological function and ultimately, viability. Because of the central role of oxygen in metabolism, it is perhaps not surprising that we have evolved an efficient and rapid molecular response system which senses hypoxia in cells, leading to the induction of an array of adaptive genes which facilitate increased oxygen supply and support anaerobic ATP generation. This response is governed by HIF (hypoxia-inducible factor). The oxygen sensitivity of this pathway is conferred by a family of hydroxylases which repress HIF activity in normoxia allowing its rapid activation in hypoxia. Because of its importance in a diverse range of disease states, the mechanism by which cells sense hypoxia and transduce a signal to the HIF pathway is an area of intense investigation. Inhibition of mitochondrial function reverses hypoxia-induced HIF leading to speculation of a role for mitochondria in cellular oxygen sensing. However, the nature of the signal between mitochondria and oxygen-sensing hydroxylase enzymes has remained controversial. In the present review, two models of the role for mitochondria in oxygen sensing will be discussed and recent evidence will be presented which raises the possibility that these two models which implicate ROS (reactive oxygen species) and oxygen redistribution respectively may complement each other and facilitate rapid and dynamic activation of the HIF pathway in hypoxia.

Дисертація на здобуття наукового ступеня кандидата технічних наук за спеціальністю 05.09.01 – електричні машини та апарати. – Національний технічний університет "Харківський політехнічний інститут", Харків, 2016. Дисертацію присвячено розробці комплексу науково-технічних рішень, спрямованих на оцінку показників лінійних електромеханічних перетворювачів ударної дії з високою магнітною сумісністю. Запропонована імітаційна математична модель лінійного електромеханічного перетворювача ударної дії, що описує взаємопов'язані просторово-часові електричні, магнітні, механічні та теплові процеси із змінними параметрами. Визначено геометричні параметри електропровідного якоря, феромагнітних осердя та екрана, при яких перетворювач забезпечує найбільші показники. Отримала подальший розвиток методика синтезу параметрів високоефективного лінійного електромеханічного перетворювача ударної дії, заснована на використанні комплексного критерію ефективності, який враховує основні показники при різних варіантах стратегії вибору. Встановлено, що кріогенне охолодження до температури рідкого азоту обмотки індуктора дозволяє збільшити ККД лінійних електромеханічних перетворювачів ударної дії в 1,6 раз, при охолодженні якоря – в 5 разів, а при одночасному їх охолодженні – в 11 разів. Розроблено конструктивні схеми лінійних електромеханічних перетворювачів ударної дії індукційно-електромагнітного типу ударної і ударно-поворотної дії. Розроблено методику експериментальних досліджень лінійних електромеханічних перетворювачів ударної дії з одночасним вимірюванням електричних і механічних показників.
The thesis for the degree of candidate of technical sciences, specialty 05.09.01 – electrical machinery and apparatus. – National technical university "Kharkiv polytechnic institute", Kharkіv, 2016. The thesis is devoted to development of complex scientific and technical solutions aimed at improving the efficiency linear electromechanical transducers with high magnetic compatibility. The proposed computer model linear electromechanical transducers with ferro-magnetic core, describing connected field-temporal electrical, magnetic, mechanical and thermal processes with variable parameters. The optimum form of section and parameters conductive anchor linear electromechanical transducers induction type. The influence of the configuration and geometrical parameters ferromagnetic core, ferromagnetic shield, electromagnetic shield and combined on screen indicators linear electromechanical transducers. Further developed methods of synthesis parameters highly linear electromechanical transducers, based on a comprehensive criteria. The effect of cryogenic cooling efficiency linear electromechanical transducers. Developed design schemes linear electromechanical transducers electromagnetic induction-type. The method of experimental studies linear electromechanical transducers simultaneous measurement of electrical and mechanical performance. Experimentally confirmed the basic theoretical training is shown linear electromechanical transducers efficiency.

Диссертация на соискание ученой степени кандидата технических наук по специальности 05.09.01 – электрические машины и аппараты. – Национальный технический университет "Харьковский политехнический институт", Харьков, 2016. Диссертация посвящена разработке комплекса научно-технических решений, направленных на оценку эффективности линейных электромеханических преобразователей ударного действия с высокой магнитной совместимости. На основе анализа научно-технических источников установлено, что линейные электромеханические преобразователи ударного действия широко при-меняются в ударно-силовых устройствах и для ускорения объектов до высоких скоростей. Однако КПД существующих линейных электромеханических преобразователей ударного действия находится на низком уровне. Кроме того, во время работы линейных электромеханических преобразователей ударного действия последние создают очень значительные импульсные магнитные поля рассеяния, которые резко негативно влияют на близко расположенное оборудование и экологическую чистоту для биологических объектов. Предложена имитационная математическая модель линейного электроме-ханического преобразователя ударного действия, описывающая взаимосвязанные пространственно-временные электрические, магнитные, механические и тепловые процессы с переменными параметрами. Определены геометрические параметры электропроводящего якоря, ферромагнитных сердечника и экрана, при которых преобразователь обеспечивает наибольшие показатели. Предложена конструкция комбинированного экрана, обеспечивающего снижение магнитных полей рассеяния до 4 раз по сравнению с ферромагнитным экраном.
The thesis for the degree of candidate of technical sciences, specialty 05.09.01 – electrical machinery and apparatus. – National technical university "Kharkiv polytechnic institute", Kharkіv, 2016. The thesis is devoted to development of complex scientific and technical solutions aimed at improving the efficiency linear electromechanical transducers with high magnetic compatibility. The proposed computer model linear electromechanical transducers with ferro-magnetic core, describing connected field-temporal electrical, magnetic, mechanical and thermal processes with variable parameters. The optimum form of section and parameters conductive anchor linear electromechanical transducers induction type. The influence of the configuration and geometrical parameters ferromagnetic core, ferromagnetic shield, electromagnetic shield and combined on screen indicators linear electromechanical transducers. Further developed methods of synthesis parameters highly linear electromechanical transducers, based on a comprehensive criteria. The effect of cryogenic cooling efficiency linear electromechanical transducers. Developed design schemes linear electromechanical transducers electromagnetic induction-type. The method of experimental studies linear electromechanical transducers simultaneous measurement of electrical and mechanical performance. Experimentally confirmed the basic theoretical training is shown linear electromechanical transducers efficiency.

The recent discovery of Iron-Gallium alloy (Galfenol) as a “large” magnetostrictive material (as high as 400 ppm) offers a particularly promising transducer material that combines largely desirable mechanical attributes with superior magnetic properties [1]. The high permeability of this material makes it easy to magnetize, however it also causes a relatively low cutoff frequency in dynamic applications, above which eddy currents form and introduce significant power losses. To reduce the eddy current losses, magnetostrictive drivers used in dynamic applications are commonly laminated. A second transducer design consideration is the introduction of an initial alignment of domains inside of the material to maximize the magnetostriction performance. It is common to achieve this by imposing an external compressive prestress to align magnetic moments perpendicular to the direction of actuation. An alternative to the application of an external prestress is to build-in a uniaxial magnetic anisotropy through stress annealing [2]. Stress annealing is a high temperature process with simultaneous application of an external load and subsequent cooling under load in which the magnetic moment alignment developed at temperature is retained upon removal from the stress annealing fixture. The external load needed to build in a useful uniaxial magnetic anisotropy in Galfenol is greater than the buckling load for Galfenol laminae sized for use in high frequency dynamic applications. In this study, prior work on stress annealing of solid rods of single and polycrystalline samples of Galfenol is successfully extended to thin laminae of Galfenol by introducing fixtures to avoid buckling of the laminae under compression during the heat treatment process. Values of the uniaxial anisotropy, cubic anisotropy, saturation magnetic induction, and saturation magnetostriction were obtained from measurements of the magnetization and magnetostriction of stress-annealed Galfenol strip as a function of compressive and tensile stress. These values were derived from fitting magnetization and magnetostriction curves to the energy expression formula [3]. Data are presented that demonstrate the magnetic uniaxial anisotropy developed by stress annealing of laminated Galfenol rods. An annealing temperature of 500 °C and a compressive stress of 200 MPa produced a uniaxial anisotropy of 11.3 kJ/m3 in this study.