Взаємний зв'язок властивостей і структури плівкових чутливих елементів сенсорів магнітного поля

Дисертацію присвячено комплексним експериментальним дослідженням особливостей структурно-фазового стану та магнітних і магніторезистивних властивостей багатошарових плівкових систем на основі Co і Cu, Co і Cr, Fe і Cr та Fe і Cu як можливих матеріалів чутливих елементів сенсорів різного призначення. У роботі встановлено взаємозв’язок між товщиною магнітних шарів і немагнітних прошарків, орієнтацією зразка у зовнішньому магнітному полі, температурою термообробки та магнітними, магніторезистивними і магнітооптичними властивостями багатошарових плівкових систем із можливим спін-залежним розсіюванням електронів. Визначені величини магнітоопору, коерцитивної сили, коефіцієнта прямокутності й чутливості плівкової системи до магнітного поля досліджуваних плівкових систем як приладових структур для формування первинних перетворювачів. Установлена кореляція між структурно-фазовим станом, магнітними та магнітооптичними властивостями тришарових плівкових систем з різним типом розчинності компонент як функціональних елементів датчиків. Запропонована схематична конструкція АМР-датчика магнітного поля для тришарових плівкових систем із спін-залежним розсіюванням електронів. У результаті проведених досліджень впливу геометрії вимірювання, температури термообробки та загальної концентрації феромагнітної компоненти в системі на магнітні й магніторезистивні властивості визначені можливі області застосування плівкових систем на основі Co і Cu або Cr та Fe і Cu або Cr.Диссертация посвящена комплексным экспериментальным исследованиям особенностей структурно-фазового состояния, магнитных магниторезистивных свойств многослойных пленочных систем на основе Co и Cu, Co и Cr, Fe и Cr и Fe и Cu в качестве возможных материалов чувствительных элементов сенсоров различного назначения. В работе установлена взаимосвязь между толщиной магнитных слоев и немагнитных прослоек, ориентацией образца во внешнем магнитном поле, температурой термообработки и магнитными, магниторезистивными и магнитооптическими свойствами многослойных пленочных систем с возможным спин-зависимым рассеянием электронов. При исследовании магнитных свойств пленочных систем на основе Fe, Co, Cu или Cr получено, что для пленочных систем на основе Fe и Cu в форме кривых гистерезиса наблюдается определенный перегиб, свидетельствующий о послойном перемагничивании слоев Fe, в то время как для систем на основе Fe и Cr петля гистерезиса имеет форму, подобную однослойным пленкам Fe, что говорит о преобладании ферромагнитной связи в системе. В пленочных структурах на основе Co и Cr или Cu магнитные свойства системы главным образом определяются состоянием слоев Со, поэтому форма кривых гистерезиса для обеих систем схожа с формой кривых для однослойных пленок Со, а небольшие значения коэрцитивной силы свидетельствуют о реализации ферромагнитной связи в системе. Все четыре системы характеризуются достаточно высоким значением коэффициента прямоугольности, которое при смене ориентации образца от 0 до 90° несколько уменьшается для систем Fe/Cu/Fe и Fe/Cr/Fe и, наоборот, растет в системах на основе Co и Cr. Определены величины магнитосопротивления, коэрцитивной силы, коэффициента прямоугольности и чувствительности пленочной системы к магнитному полю исследуемых пленочных систем как приборных структур для формирования первичных преобразователей. Установлена корреляция между структурно-фазовым состоянием, магнитными и магнитооптическими свойствами трехслойных пленочных систем с разным типом растворимости компонент в качестве функциональных элементов датчиков. Предложена схематическая конструкция АМР-датчика магнитного поля для трехслойных пленочных систем со спин-зависимым рассеянием электронов. В результате проведенных исследований влияния геометрии измерения, температуры термообработки и общей концентрации ферромагнитной компоненты в системе на магниторезистивные свойства определены возможные области применения пленочных систем на основе Co и Cu или Cr и Fe и Cu или Cr.The thesіs іs dedіcаted to the complex experіmentаl reseаrch between the structurаl-phаse stаte, magnetic and magnetoresistance propertіes of multіlаyer fіlm systems bаsed on the Co аnd Cu, Co аnd Cr, Fe аnd Cr, аnd Fe аnd Cu, аs the potential mаterіаls for sensіtіve elements of sensors for dіfferent purposes. Іn thіs thesis wаs found the correlаtіon between the thіckness of the mаgnetіc аnd nonmаgnetіc lаyers, the orіentаtіon of the sаmple іn аn externаl mаgnetіc fіeld, temperаture of heаt treаtment аnd mаgnetіc, mаgnetoresіstіve аnd mаgneto-optіcаl propertіes іn multіlаyer fіlm systems wіth possіble spіn-dependent scаtterіng of electrons. The vаlues of mаgnetoresіstаnce, coercіvіty, squаreness fаctor аnd sensіtіvіty of fіlm system to a mаgnetіc fіeld in the studіed fіlm systems аs devіce structures for the formаtіon of prіmаry converters were defined. The correlаtіon between the structurаl-phаse stаte, mаgnetіc аnd mаgneto-optіcаl propertіes of three-lаyer fіlm systems wіth dіfferent types of component solubіlіty аs functіonаl elements sensors was established. The schemаtіc sturucture of АMR sensor for three-lаyer fіlm systems wіth spіn-dependent scаtterіng of electrons was purposed. The possіble аreаs of аpplіcаtіons wаs іdentіfіed on the bаsіs of studіes of the effect of geometry meаsurement temperаture heаt treаtment аnd the totаl concentrаtіon of ferromаgnetіc components іn the system on the magnetic and mаgnetoresіstіve propertіes of fіlm-systems bаsed on Co аnd Cu, or Cr аnd Fe, аnd Cu or Cr

Management control systems in innovation companies: A literature based framework

Past research has traditionally argued that management control systems (MCSs) may present a hindrance to the creativity of innovation companies. This theoretical paper surveys the literature to focus an investigation on the MCSs of innovation companies. Within the object of control paradigm the paper develops and presents a theoretical model of the impact of eleven external, organisational and innovation related contingency factors on the MCSs in companies that engage in innovation activities. We also suggest measures for further empirical research. By formulating hypotheses on 43 potential interactions the model predicts contradictory influences on two direct control categories, results and action control, but stresses the importance of two indirect categories, personnel and cultural control. More specifically, the high levels of technological complexity and innovation capability in this type of company are expected to be negatively associated with the application of results and action control, whereas personnel and cultural seem to be more appropriate. Furthermore, important sources of finance, venture capital and public funding, are both hypothesised to be positively associated with the application of results, action and personnel control; whereas only public funding is predicted to be positively related to the application of cultural control. The principal contribution of this paper lies in synthesising the literature to provide a model of the impact of a unique set of eleven contingency factors for innovation companies on a broad scope of controls. In addition, the contingency model, if empirically validated, would add value by inferring the particular forms of management control which would be beneficial in innovative company settings. © 2014 Springer-Verlag Berlin Heidelberg

Is bioelectrical impedance accurate for use in large epidemiological studies?

Percentage of body fat is strongly associated with the risk of several chronic diseases but its accurate measurement is difficult. Bioelectrical impedance analysis (BIA) is a relatively simple, quick and non-invasive technique, to measure body composition. It measures body fat accurately in controlled clinical conditions but its performance in the field is inconsistent. In large epidemiologic studies simpler surrogate techniques such as body mass index (BMI), waist circumference, and waist-hip ratio are frequently used instead of BIA to measure body fatness. We reviewed the rationale, theory, and technique of recently developed systems such as foot (or hand)-to-foot BIA measurement, and the elements that could influence its results in large epidemiologic studies. BIA results are influenced by factors such as the environment, ethnicity, phase of menstrual cycle, and underlying medical conditions. We concluded that BIA measurements validated for specific ethnic groups, populations and conditions can accurately measure body fat in those populations, but not others and suggest that for large epdiemiological studies with diverse populations BIA may not be the appropriate choice for body composition measurement unless specific calibration equations are developed for different groups participating in the study

Role of high tibial osteotomy in chronic injuries of posterior cruciate ligament and posterolateral corner

High tibial osteotomy (HTO) is a surgical procedure used to change the mechanical weight-bearing axis and alter the loads carried through the knee. Conventional indications for HTO are medial compartment osteoarthritis and varus malalignment of the knee causing pain and dysfunction. Traditionally, knee instability associated with varus thrust has been considered a contraindication. However, today the indications include patients with chronic ligament deficiencies and malalignment, because an HTO procedure can change not only the coronal but also the sagittal plane of the knee. The sagittal plane has generally been ignored in HTO literature, but its modification has a significant impact on biomechanics and joint stability. Indeed, decreased posterior tibial slope causes posterior tibia translation and helps the anterior cruciate ligament (ACL)-deficient knee. Vice versa, increased tibial slope causes anterior tibia translation and helps the posterior cruciate ligament (PCL)-deficient knee. A review of literature shows that soft tissue procedures alone are often unsatisfactory for chronic posterior instability if alignment is not corrected. Since limb alignment is the most important factor to consider in lower limb reconstructive surgery, diagnosis and treatment of limb malalignment should not be ignored in management of chronic ligamentous instabilities. This paper reviews the effects of chronic posterior instability and tibial slope alteration on knee and soft tissues, in addition to planning and surgical technique for chronic posterior and posterolateral instability with HTO

Modulation of TRAIL resistance in colon carcinoma cells: Different contributions of DR4 and DR5

<p>Abstract</p> <p>Background</p> <p>rhTRAIL is a therapeutic agent, derived from the TRAIL cytokine, which induces apoptosis in cancer cells by activating the membrane death receptors 4 and 5 (DR4 and DR5). Here, we investigated each receptor's contribution to rhTRAIL sensitivity and rhTRAIL resistance. We assessed whether agonistic DR4 or DR5 antibodies could be used to circumvent rhTRAIL resistance, alone or in combination with various chemotherapies.</p> <p>Methods</p> <p>Our study was performed in an isogenic model comprised of the SW948 human colon carcinoma cell line and its rhTRAIL resistant sub-line SW948-TR. Effects of rhTRAIL and agonistic DR4/DR5 antibodies on cell viability were measured using MTT assays and identification of morphological changes characteristic of apoptosis, after acridine orange staining. Sensitivity to the different death receptor ligands was stimulated using pretreatment with the cytokine IFN-gamma and the proteasome inhibitor MG-132. To investigate the mechanisms underlying the changes in rhTRAIL sensitivity, alterations in expression levels of targets of interest were measured by Western blot analysis. Co-immunoprecipitation was used to determine the composition of the death-inducing signalling complex at the cell membrane.</p> <p>Results</p> <p>SW948 cells were sensitive to all three of the DR-targeting agents tested, although the agonistic DR5 antibody induced only weak caspase 8 cleavage and limited apoptosis. Surprisingly, agonistic DR4 and DR5 antibodies induced equivalent DISC formation and caspase 8 cleavage at the level of their individual receptors, suggesting impairment of further caspase 8 processing upon DR5 stimulation. SW948-TR cells were cross-resistant to all DR-targeting agents as a result of decreased caspase 8 expression levels. Caspase 8 protein expression was restored by MG-132 and IFN-gamma pretreatment, which also re-established sensitivity to rhTRAIL and agonistic DR4 antibody in SW948-TR. Surprisingly, MG-132 but not IFN-gamma could also increase DR5-mediated apoptosis in SW948-TR.</p> <p>Conclusions</p> <p>These results highlight a critical difference between DR4- and DR5-mediated apoptotic signaling modulation, with possible implications for future combinatorial regimens.</p

Alteration of Proteins and Pigments Influence the Function of Photosystem I under Iron Deficiency from Chlamydomonas reinhardtii

BACKGROUND: Iron is an essential micronutrient for all organisms because it is a component of enzyme cofactors that catalyze redox reactions in fundamental metabolic processes. Even though iron is abundant on earth, it is often present in the insoluble ferric [Fe (III)] state, leaving many surface environments Fe-limited. The haploid green alga Chlamydomonas reinhardtii is used as a model organism for studying eukaryotic photosynthesis. This study explores structural and functional changes in PSI-LHCI supercomplexes under Fe deficiency as the eukaryotic photosynthetic apparatus adapts to Fe deficiency. RESULTS: 77K emission spectra and sucrose density gradient data show that PSI and LHCI subunits are affected under iron deficiency conditions. The visible circular dichroism (CD) spectra associated with strongly-coupled chlorophyll dimers increases in intensity. The change in CD signals of pigments originates from the modification of interactions between pigment molecules. Evidence from sucrose gradients and non-denaturing (green) gels indicates that PSI-LHCI levels were reduced after cells were grown for 72 h in Fe-deficient medium. Ultrafast fluorescence spectroscopy suggests that red-shifted pigments in the PSI-LHCI antenna were lost during Fe stress. Further, denaturing gel electrophoresis and immunoblot analysis reveals that levels of the PSI subunits PsaC and PsaD decreased, while PsaE was completely absent after Fe stress. The light harvesting complexes were also susceptible to iron deficiency, with Lhca1 and Lhca9 showing the most dramatic decreases. These changes in the number and composition of PSI-LHCI supercomplexes may be caused by reactive oxygen species, which increase under Fe deficiency conditions. CONCLUSIONS: Fe deficiency induces rapid reduction of the levels of photosynthetic pigments due to a decrease in chlorophyll synthesis. Chlorophyll is important not only as a light-harvesting pigment, but also has a structural role, particularly in the pigment-rich LHCI subunits. The reduced level of chlorophyll molecules inhibits the formation of large PSI-LHCI supercomplexes, further decreasing the photosynthetic efficiency

Back to the sea twice: identifying candidate plant genes for molecular evolution to marine life

Background: Seagrasses are a polyphyletic group of monocotyledonous angiosperms that have adapted to a completely submerged lifestyle in marine waters. Here, we exploit two collections of expressed sequence tags (ESTs) of two wide-spread and ecologically important seagrass species, the Mediterranean seagrass Posidonia oceanica (L.) Delile and the eelgrass Zostera marina L., which have independently evolved from aquatic ancestors. This replicated, yet independent evolutionary history facilitates the identification of traits that may have evolved in parallel and are possible instrumental candidates for adaptation to a marine habitat. Results: In our study, we provide the first quantitative perspective on molecular adaptations in two seagrass species. By constructing orthologous gene clusters shared between two seagrasses (Z. marina and P. oceanica) and eight distantly related terrestrial angiosperm species, 51 genes could be identified with detection of positive selection along the seagrass branches of the phylogenetic tree. Characterization of these positively selected genes using KEGG pathways and the Gene Ontology uncovered that these genes are mostly involved in translation, metabolism, and photosynthesis. Conclusions: These results provide first insights into which seagrass genes have diverged from their terrestrial counterparts via an initial aquatic stage characteristic of the order and to the derived fully-marine stage characteristic of seagrasses. We discuss how adaptive changes in these processes may have contributed to the evolution towards an aquatic and marine existence

The properties and applications of single-molecule DNA sequencing

Single-molecule sequencing enables DNA or RNA to be sequenced directly from biological samples, making it well-suited for diagnostic and clinical applications. Here we review the properties and applications of this rapidly evolving and promising technology

Endocrinologic, neurologic, and visual morbidity after treatment for craniopharyngioma

Craniopharyngiomas are locally aggressive tumors which typically are focused in the sellar and suprasellar region near a number of critical neural and vascular structures mediating endocrinologic, behavioral, and visual functions. The present study aims to summarize and compare the published literature regarding morbidity resulting from treatment of craniopharyngioma. We performed a comprehensive search of the published English language literature to identify studies publishing outcome data of patients undergoing surgery for craniopharyngioma. Comparisons of the rates of endocrine, vascular, neurological, and visual complications were performed using Pearson’s chi-squared test, and covariates of interest were fitted into a multivariate logistic regression model. In our data set, 540 patients underwent surgical resection of their tumor. 138 patients received biopsy alone followed by some form of radiotherapy. Mean overall follow-up for all patients in these studies was 54 ± 1.8 months. The overall rate of new endocrinopathy for all patients undergoing surgical resection of their mass was 37% (95% CI = 33–41). Patients receiving GTR had over 2.5 times the rate of developing at least one endocrinopathy compared to patients receiving STR alone or STR + XRT (52 vs. 19 vs. 20%, χ2P < 0.00001). On multivariate analysis, GTR conferred a significant increase in the risk of endocrinopathy compared to STR + XRT (OR = 3.45, 95% CI = 2.05–5.81, P < 0.00001), after controlling for study size and the presence of significant hypothalamic involvement. There was a statistical trend towards worse visual outcomes in patients receiving XRT after STR compared to GTR or STR alone (GTR = 3.5% vs. STR 2.1% vs. STR + XRT 6.4%, P = 0.11). Given the difficulty in obtaining class 1 data regarding the treatment of this tumor, this study can serve as an estimate of expected outcomes for these patients, and guide decision making until these data are available