483 research outputs found

    Bounded Linear Stability Margin Analysis of Nonlinear Hybrid Adaptive Control

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    This paper presents a bounded linear stability analysis for a hybrid adaptive control that blends both direct and indirect adaptive control. Stability and convergence of nonlinear adaptive control are analyzed using an approximate linear equivalent system. A stability margin analysis shows that a large adaptive gain can lead to a reduced phase margin. This method can enable metrics-driven adaptive control whereby the adaptive gain is adjusted to meet stability margin requirements

    Antioxidant and cytotoxic potential of selected plant species of the boraginaceae family

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    Antioxidant activity is one of the most important properties of plant extracts. Antioxidants from natural sources have been intensively studied in the last few decades. The antioxidant contents of medicinal plants may contribute to the protection of diseases. Bioactive components of plants have a potential role in chemoprevention and inhibition of different phases of the malignant transformation process. Therefore, plant extracts and essential oils are in the focus of research, and in recent decades have been tested on a large number of malignant cell lines. The aim of this study was to examine antioxidant and cytotoxic potential of selected plant species from the Boraginaceae family. Determination of antioxidant activity was performed by ammonium-thiocyanate method. Testing citotoxic activity was performed by MTT test on cancer cell lines: HEP 2c (human larynx carcinoma), RD (human cell line-rhabdomyosarcoma) and L2OB (mouse tumor fibroblast line). The best antioxidant activity showed ethanol, acetone and chloroform extracts of Anchusa officinalis, Echium vulgare and Echium italicum. The tested extracts showed an inhibitory effect on cancer cells, but chloroform and acetone extracts of all three plant had the most effective effect on L2OB cells. Isolation of individual active components from this plants and their testing for cancer cells would be of great importance for this field of research

    An Integrated Approach to Damage Accommodation in Flight Control

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    In this paper we present an integrated approach to in-flight damage accommodation in flight control. The approach is based on Multiple Models, Switching and Tuning (MMST), and consists of three steps: In the first step the main objective is to acquire a realistic aircraft damage model. Modeling of in-flight damage is a highly complex problem since there is a large number of issues that need to be addressed. One of the most important one is that there is strong coupling between structural dynamics, aerodynamics, and flight control. These effects cannot be studied separately due to this coupling. Once a realistic damage model is available, in the second step a large number of models corresponding to different damage cases are generated. One possibility is to generate many linear models and interpolate between them to cover a large portion of the flight envelope. Once these models have been generated, we will implement a recently developed-Model Set Reduction (MSR) technique. The technique is based on parameterizing damage in terms of uncertain parameters, and uses concepts from robust control theory to arrive at a small number of "centered" models such that the controllers corresponding to these models assure desired stability and robustness properties over a subset in the parametric space. By devising a suitable model placement strategy, the entire parametric set is covered with a relatively small number of models and controllers. The third step consists of designing a Multiple Models, Switching and Tuning (MMST) strategy for estimating the current operating regime (damage case) of the aircraft, and switching to the corresponding controller to achieve effective damage accommodation and the desired performance. In the paper present a comprehensive approach to damage accommodation using Model Set Design,MMST, and Variable Structure compensation for coupling nonlinearities. The approach was evaluated on a model of F/A-18 aircraft dynamics under control effector damage, augmented by nonlinear cross-coupling terms and a structural dynamics model. The proposed approach achieved excellent performance under severe damage effects

    Correlation analysis of milk production traits across three generations of Simmental cows

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    The relationship between milk production traits over whole lactations was evaluated across three generations of Simmental cows (between daughters, dams and granddams) by a corelation analysis with whole lactation traits in the daughter generation being used as the dependent variables (x<sub>1</sub>), and those in the dam and granddam generations being used as the independent variables (x<sub>2</sub> and  x<sub>3</sub>). The results were obtained from a sample of 1170 daughters and as many dams and  granddams. The correlation of whole lactation milk production traits between daughters, dams and  granddams, as calculated by simple, partial and multiple correlation coefficients was very weak or  non-existent. All of the calculated simple and partial correlation coefficients were positive and mostly  statistically very significant (P<0.01). The calculated coefficients of multiple correlation (R1.23) between  lactation length, milk fat content, milk yield, milk fat yield and 4% FCM yield with the expression of the traits in the daughters being used as the dependent variable and that in the dams and granddams as the independent variable were statistically very significant (P<0.01), amounting to 0.091, 0.251, 0.180, 0.133 and 0.153, respectively.Key words: Simmental breed, production traits, generation, coefficient of partial correlation, coefficient of multiple correlation

    Performance, intestinal histomorphology and bone composition of broiler chickens fed diets supplemented with genistein

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    The effect of dietary genistein on performance, intestinal morphology, caecal Lactobacillus spp. count, and tibia composition in broiler chickens after 21 and 37 days of feeding was investigated. A total of 360 Cobb 500 broiler chickens (21 days old) were randomly allocated to five treatments with six replicates of 12 birds each. They were fed a basal diet (C) or a basal diet supplemented with 200 (T1), 400 (T2), 600 (T3) and 800 (T4) mg genistein/kg of feed. Genistein supplementation did not affect feed intake, but improved bodyweight, weight gain and feed conversion ratio (FCR) after 21 days, while 600 mg/kg led to a significant increase in FCR after 37 days of feeding. Plasma triglyceride level decreased with dietary genistein after 21 days, while increases were found in T3 and T4 groups after prolonged supplementation. Significantly improved duodenal and jejunal villus length and width, crypt depth and villus/crypt ratio were observed after the first and the second finishing periods, respectively, while adverse effects were found in the ileum for both periods. At 42 days old, greater spleen and heart weights were measured in broilers fed diets with 800 mg/kg than in other broiler groups. The shorter genistein supplementation period (21 days) of 200 and 400 mg/kg had a positive effect on tibia wet weight, ash and calcium (Ca) content, while 37 days of the higher genistein doses administered to the T2, T3 and T4 birds significantly increased caecal lactic acid bacteria (LAB) counts. Thus, recommended doses should not exceed 400 mg/kg. Keywords: broiler performance, blood triglyceride, Lactobacillus, prolonged fattening, small intestinal morpholog

    A systematic review and meta-analyses of pregnancy and fetal outcomes in women with multiple sclerosis: a contribution from the IMI2 ConcePTION project.

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    Neurologists managing women with Multiple Sclerosis (MS) need information about the safety of disease modifying drugs (DMDs) during pregnancy. However, this knowledge is limited. The present study aims to summarize previous studies by performing a systematic review and meta-analyses. The terms "multiple sclerosis" combined with DMDs of interest and a broad profile for pregnancy terms were used to search Embase and Medline databases to identify relevant studies published from January 2000 to July 2019.1260 studies were identified and ten studies met our inclusion criteria. Pooled risk ratios (RR) of pregnancy and birth outcomes in pregnancies exposed to DMDs compared to those not exposed were calculated using a random effects model. For spontaneous abortion RR = 1.14, 95% CI 0.99-1.32, for preterm births RR = 0.93, 95% CI 0.72-1.21 and for major congenital malformations RR = 0.86, 95% CI 0.47-1.56. The most common major congenital malformations reported in MS patients exposed to MS drugs were atrial septal defect (ASD) (N = 4), polydactyly (N = 4) and club foot (N = 3), which are among the most prevalent birth defects observed in the general population. In conclusion, interferons, glatiramer acetate or natalizumab, do not appear to increase the risk for spontaneous abortions, pre-term birth or major congenital malformations. There were very few patients included that were exposed to fingolimod, azathioprine and rituximab; therefore, these results cannot be generalized across drugs. Future studies including internal comparators are needed to enable treating physicians and their patients to decide on the best treatment options

    Microbubble-mediated delivery of human adenoviruses does not elicit innate and adaptive immunity response in an immunocompetent mouse model of prostate cancer

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    © 2019 by the authors. Licensee MDPI, Basel, Switzerland. Lack of standardization of clinically compliant culture protocols of mesenchymal stem cells for re-implantation in humans have hindered clinical progress in the field of tissue regeneration to repair maxillofacial and orthopedic defects. The goal of this study was to establish a clinically relevant osteogenic protocol for collection and expansion of autologous stem cells to be used at Marshall University for re-implantation and repair of maxillofacial and orthopedic conditions. Human bone marrow (hBM) samples were collected from patients undergoing intramedullary nail fixation for closed femoral fractures. hBM mesenchymal cells were expanded by growing them first in Petri dishes for two weeks, followed by a week of culture using Perfecta 3D Hanging Drop Plates®. Various scaffold materials were tested and analyzed for cellular integration, vitality, and differentiation capacity of harvested hBM-MSCs including: 60/40 blend of hydroxyapatite biomatrix; Acellular bone composite discs; Allowash®, cancellous bone cubes; PLGA (poly lactic-co-glycolic acid); and Woven chitin derived fiber. We found that the 3D spheroid culture allowed production of hBM mesenchymal cells that retained osteoblast differentiation capacity over a monolayer culture of hBM-MSCs without the need to use chemical or hormonal modulation. We also observed that hydroxyapatite and Allowash cancellous bone scaffolds allowed better cell integration and viability properties as compared to other materials tested in this study. In conclusion, the multimodal culture methodology we developed creates actively differentiating stem-cell spheroids that can then be readily utilized in clinical practices to improve the regeneration of tissues of the head and the body

    Spin-parity dependent tunneling of magnetization in single-molecule magnets

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    Single-molecule magnets facilitate the study of quantum tunneling of magnetization at the mesoscopic level. The spin-parity effect is among the fundamental predictions that have yet to be clearly observed. It is predicted that quantum tunneling is suppressed at zero transverse field if the total spin of the magnetic system is half-integer (Kramers degeneracy) but is allowed in integer spin systems. The Landau-Zener method is used to measure the tunnel splitting as a function of transverse field. Spin-parity dependent tunneling is established by comparing the transverse field dependence of the tunnel splitting of integer and half-integer spin systems.Comment: 4 pages, 6 figure

    Auditory Event-Related P300 Potentials in Rheumatoid Arthritis Patients

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    The aim of the study was to assess P300 event-related potentials (ERPs) in patients suffering from rheumatoid arthritis (RA) in relation to the duration of illness, degree of disease activity, anatomical and functional stage of the disease, pain intensity, and pain unpleasantness. The cross-sectional study included 53 women with RA (RA group; mean age 50.58 ± 0.93 years) and 27 healthy women (control group, C; 49.41 ± 1.08 years). The intensity and unpleasantness of pain were determined using a visual analog scale (VAS); the functional status was assessed using HAQ (Health Assessment Questionnaire), and the disease activity was estimated using the disease activity scale (DAS28). The P300 waves initiated by auditory stimulations according to the oddball paradigm were recorded from leads Fz and Cz. There were no significant differences between the P300 latencies in both leads. At the same time, the average P300 amplitudes in both leads were found to be considerably lower (P < 0.05) in the RA group compared to the C group. Thus, there is a statistically significant amplitude difference between the P300 cognitive ERPs in RA patients and control subjects.Були досліджені параметри пов’язаних із подією потенціалів (ППП) P300 у пацієнтів, що страждають на ревматоїдний артрит (РА), та зв’язок цих параметрів із тривалістю та інтенсивністю захворювання, анатомічною та функціональною стадіями останнього, інтенсивністю та неприємністю відчуттів болю. У порівняльне дослідження були залучені 53 жінки з РА (група RA, середній вік 50.58 ± ± 0.94 року) та 27 здорових жінок (контрольна група C, 49.41 ± 1.08 року). Інтенсивність та рівень неприємності болю визначали за допомогою візуальної аналогової шкали (VAS), функціональний статус – згідно з опитувальником HAQ, а інтенсивність хвороби – за шкалою DAS28. Потенціали P300 ініціювали акустичною стимуляцією відповідно до oddball-парадигми та відводили від точок Fz та Cz. Усереднені значення латентних періодів хвилі P300 в групах RA та C не демонстрували якихось істотних відмінностей. У той же час усереднені амплітуди P300 в обох кортикальних зонах у групі RA були вірогідно нижчими (P < 0.05), ніж відповідні величини в групі C. Таким чином, існує статистично значуща різниця між характеристиками когнітивного ППП P300 у пацієнтів із ревматоїдним артритом та здорових суб’єктів, що вказує на негативні зміни сенсорного процесінга та уваги, а також когнітивні дисфункції, виниклі під впливом хронічного болю

    Genetic evidence that two independent S-loci control RNase-based self-incompatibility in diploid strawberry

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    The self-incompatibility mechanism that reduces inbreeding in many plants of the Rosaceae is attributed to a multi-allelic S locus which, in the Prunoideae and Maloideae subfamilies, comprises two complementary genes, a stylar-expressed S-RNase and a pollen-expressed SFB. To elucidate incompatibility in the subfamily Rosoideae, stylar-specific RNases and self-(in)compatibility status were analysed in various diploid strawberries, especially Fragaria nubicola and F. viridis, both self-incompatible, and F. vesca, self-compatible, and in various progenies derived from them. Unexpectedly, two unlinked RNase loci, S and T, were found, encoding peptides distinct from Prunoideae and Maloideae S-RNases; the presence of a single active allele at either is sufficient to confer self-incompatibility. By contrast, in diploid Maloideae and Prunoideae a single locus encodes S-RNases that share several conserved regions and two active alleles are required for self-incompatibility. Our evidence implicates the S locus in unilateral inter-specific incompatibility and shows that S and T RNases can, remarkably, confer not only allele-specific rejection of cognate pollen but also unspecific rejection of Sn Tn pollen, where n indicates a null allele, consistent with the the presence of the pollen component, SFB, activating the cognitive function of these RNases. Comparison of relevant linkage groups between Fragaria and Prunus suggests that Prunus S-RNases, unique in having two introns, may have resulted from gene conversion in an ancestor of Prunus. In addition, it is shown that there is a non-S locus that is essential for self-incompatibility in diploid Fragaria
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