Science.gov

Sample records for actively controlled partial

  1. Semi-active control of a sandwich beam partially filled with magnetorheological elastomer

    NASA Astrophysics Data System (ADS)

    Dyniewicz, Bartłomiej; Bajkowski, Jacek M.; Bajer, Czesław I.

    2015-08-01

    The paper deals with the semi-active control of vibrations of structural elements. Elastomer composites with ferromagnetic particles that act as magnetorheological fluids are used. The damping coefficient and the shear modulus of the elastomer increases when it is exposed to an electro-magnetic field. The control of this process in time allows us to reduce vibrations more effectively than if the elastomer is permanently exposed to a magnetic field. First the analytical solution for the vibrations of a sandwich beam filled with an elastomer is given. Then the control problem is defined and applied to the analytical formula. The numerical solution of the minimization problem results in a periodic, perfectly rectangular control function if free vibrations are considered. Such a temporarily acting magnetic field is more efficient than a constantly acting one. The surplus reaches 20-50% or more, depending on the filling ratio of the elastomer. The resulting control was verified experimentally in the vibrations of a cantilever sandwich beam. The proposed semi-active control can be directly applied to engineering vibrating structural elements, for example helicopter rotors, aircraft wings, pads under machines, and vehicles.

  2. Vibration reduction in helicopter rotors using an actively controlled partial span trailing edge flap located on the blade

    NASA Technical Reports Server (NTRS)

    Millott, T. A.; Friedmann, P. P.

    1994-01-01

    This report describes an analytical study of vibration reduction in a four-bladed helicopter rotor using an actively controlled, partial span, trailing edge flap located on the blade. The vibration reduction produced by the actively controlled flap (ACF) is compared with that obtained using individual blade control (IBC), in which the entire blade is oscillated in pitch. For both cases a deterministic feedback controller is implemented to reduce the 4/rev hub loads. For all cases considered, the ACF produced vibration reduction comparable with that obtained using IBC, but consumed only 10-30% of the power required to implement IBC. A careful parametric study is conducted to determine the influence of blade torsional stiffness, spanwise location of the control flap, and hinge moment correction on the vibration reduction characteristics of the ACF. The results clearly demonstrate the feasibility of this new approach to vibration reduction. It should be emphasized than the ACF, used together with a conventional swashplate, is completely decoupled from the primary flight control system and thus it has no influence on the airworthiness of the helicopter. This attribute is potentially a significant advantage when compared to IBC.

  3. HIV-induced T-cell activation/exhaustion in rectal mucosa is controlled only partially by antiretroviral treatment.

    PubMed

    Rueda, Cesar Mauricio; Velilla, Paula Andrea; Chougnet, Claire A; Montoya, Carlos Julio; Rugeles, Maria Teresa

    2012-01-01

    Peripheral blood T-cells from untreated HIV-1-infected patients exhibit reduced immune responses, usually associated with a hyperactivated/exhausted phenotype compared to HAART treated patients. However, it is not clear whether HAART ameliorates this altered phenotype of T-cells in the gastrointestinal-associated lymphoid tissue (GALT), the main site for viral replication. Here, we compared T-cells from peripheral blood and GALT of two groups of chronically HIV-1-infected patients: untreated patients with active viral replication, and patients on suppressive HAART. We characterized the T-cell phenotype by measuring PD-1, CTLA-4, HLA-DR, CD25, Foxp3 and granzyme A expression by flow cytometry; mRNA expression of T-bet, GATA-3, ROR-γt and Foxp3, and was also evaluated in peripheral blood mononuclear cells and rectal lymphoid cells. In HIV-1+ patients, the frequency of PD-1(+) and CTLA-4(+) T-cells (both CD4+ and CD8+ T cells) was higher in the GALT than in the blood. The expression of PD-1 by T-cells from GALT was higher in HIV-1-infected subjects with active viral replication compared to controls. Moreover, the expression per cell of PD-1 and CTLA-4 in CD4(+) T-cells from blood and GALT was positively correlated with viral load. HAART treatment decreased the expression of CTLA-4 in CD8(+) T cells from blood and GALT to levels similar as those observed in controls. Frequency of Granzyme A(+) CD8(+) T-cells in both tissues was low in the untreated group, compared to controls and HAART-treated patients. Finally, a switch towards Treg polarization was found in untreated patients, in both tissues. Together, these findings suggest that chronic HIV-1 infection results in an activated/exhausted T-cell phenotype, despite T-cell polarization towards a regulatory profile; these alterations are more pronounced in the GALT compared to peripheral blood, and are only partiality modulated by HAART. PMID:22276176

  4. Partially decentralized control for ALSTOM gasifier.

    PubMed

    Tan, Wen; Lou, Guannan; Liang, Luping

    2011-07-01

    The gasifier plays a key role in the operation of the whole IGCC power plant. It is a typical multivariable control system with strict constraints on the inputs and outputs which makes it very difficult to control. This paper presents a partially decentralized controller design method based on the stabilizer idea. The method only requires identifying some closed-loop transfer functions and solving an H(∞) optimization problem. The final partially decentralized controller is easy to implement and test in practice. Two partially decentralized controllers are designed for the ALSTOM gasifier benchmark problem, and simulation results show that they both meet the design specifications. PMID:21356534

  5. Differential partial activation phenotype and production of tumour necrosis factor-α by conventional dendritic cells in response to lipopolysaccharide in HIV+ viraemic subjects and HIV+ controllers

    PubMed Central

    Camacho-Sandoval, R; Del Río Estrada, P M; Rivero-Arrieta, A; Reyes-Terán, G; Bonifaz, L C

    2014-01-01

    HIV+ subjects are reported to have increased soluble CD14 (sCD14) in plasma, an indicator of microbial translocation. We evaluated if microbial translocation has a differential impact on the activation and function of conventional dendritic cells (cDC) from viraemic HIV+ subjects and HIV+ controllers (CTs). The HIV+ subjects were classified into two groups according to their plasma viral load (pVL): CT and viraemic. Subjects without HIV were included as controls (HIV–). The frequencies and phenotypes of cDC from these subjects were evaluated by multi-parameter flow cytometry. In addition, peripheral blood mononuclear cells (PBMCs) were stimulated with lipopolysaccharide (LPS) or single-stranded RNA40 (ssRNA40), the phenotype of the cDC and the intracellular production of tumour necrosis factor (TNF)-α by the cDC were evaluated by flow cytometry. We observed a partial activation phenotype for the cDC in the viraemic subjects and CTs ex vivo and after LPS activation, which showed differences in the expression of CD40 and CD86. Furthermore, in response to LPS the cDC from the viraemic subjects produced more TNF-α compared to the cDC from CTs. Interestingly, the percentage of TNF-α+ cDC was found to be correlated positively with the pVL. The partial activation of cDC and the over-production of TNF-α in response to LPS in viraemic HIV+ subjects might be related to the increased chronic activation observed in these subjects. In contrast, cDC from CTs seem to have a regulated response to LPS, indicating that they respond differently to chronic immune activation. These results may have implications in the development of HIV therapies and vaccines using DC. PMID:25130456

  6. DEVICE FOR CONTROL OF OXYGEN PARTIAL PRESSURE

    DOEpatents

    Bradner, H.; Gordon, H.S.

    1957-12-24

    A device is described that can sense changes in oxygen partial pressure and cause a corresponding mechanical displacement sufficient to actuate meters, valves and similar devices. A piston and cylinder arrangement contains a charge of crystalline metal chelate pellets which have the peculiar property of responding to variations in the oxygen content of the ambient atmosphere by undergoing a change in dimension. A lever system amplifies the relative displacement of the piston in the cylinder, and actuates the controlled valving device. This partial pressure oxygen sensing device is useful in controlled chemical reactions or in respiratory devices such as the oxygen demand meters for high altitude aircraft.

  7. Partially Decentralized Control Architectures for Satellite Formations

    NASA Technical Reports Server (NTRS)

    Carpenter, J. Russell; Bauer, Frank H.

    2002-01-01

    In a partially decentralized control architecture, more than one but less than all nodes have supervisory capability. This paper describes an approach to choosing the number of supervisors in such au architecture, based on a reliability vs. cost trade. It also considers the implications of these results for the design of navigation systems for satellite formations that could be controlled with a partially decentralized architecture. Using an assumed cost model, analytic and simulation-based results indicate that it may be cheaper to achieve a given overall system reliability with a partially decentralized architecture containing only a few supervisors, than with either fully decentralized or purely centralized architectures. Nominally, the subset of supervisors may act as centralized estimation and control nodes for corresponding subsets of the remaining subordinate nodes, and act as decentralized estimation and control peers with respect to each other. However, in the context of partially decentralized satellite formation control, the absolute positions and velocities of each spacecraft are unique, so that correlations which make estimates using only local information suboptimal only occur through common biases and process noise. Covariance and monte-carlo analysis of a simplified system show that this lack of correlation may allow simplification of the local estimators while preserving the global optimality of the maneuvers commanded by the supervisors.

  8. Mitochondrial quality control, promoted by PGC-1α, is dysregulated by Western diet-induced obesity and partially restored by moderate physical activity in mice

    PubMed Central

    Greene, Nicholas P; Lee, David E; Brown, Jacob L; Rosa, Megan E; Brown, Lemuel A; Perry, Richard A; Henry, Jordyn N; Washington, Tyrone A

    2015-01-01

    Skeletal muscle mitochondrial degeneration is a hallmark of insulin resistance/obesity marked by lost function, enhanced ROS emission, and altered morphology which may be ameliorated by physical activity (PA). However, no prior report has examined mitochondrial quality control regulation throughout biogenesis, fusion/fission dynamics, autophagy, and mitochondrial permeability transition pore (MPTP) in obesity. Therefore, we determined how each process is impacted by Western diet (WD)-induced obesity and whether voluntary PA may alleviate derangements in mitochondrial quality control mechanisms. Despite greater mitochondrial content following WD (COX-IV and Cytochrome C), induction of biogenesis controllers appears impaired (failed induction of PGC-1α). Mitochondrial fusion seems diminished (reduced MFN2, Opa1 proteins), with no significant changes in fission, suggesting a shift in balance of dynamics regulation favoring fission. Autophagy flux was promoted in WD (reduced p62, increased LC3II:I ratio); however, mitophagy marker BNIP3 is reduced in WD which may indicate reduced mitophagy despite enhanced total autophagy flux. MPTP regulator Ant mRNA is reduced by WD. Few processes were impacted by physical activity. Finally, mitochondrial quality control processes are partially promoted by PGC-1α, as PGC-1α transgenic mice display elevated mitochondrial biogenesis and autophagy flux. Additionally, these mice exhibit elevated Mfn1 and Opa1 mRNA, with no change in protein content suggesting these factors are transcriptionally promoted by PGC-1α overexpression. These data demonstrate dysfunctions across mitochondrial quality control in obesity and that PGC-1α is sufficient to promote multiple, but not necessarily all, aspects of mitochondrial quality control. Mitochondrial quality control may therefore be an opportune target to therapeutically treat metabolic disease. PMID:26177961

  9. Mitochondrial quality control, promoted by PGC-1α, is dysregulated by Western diet-induced obesity and partially restored by moderate physical activity in mice.

    PubMed

    Greene, Nicholas P; Lee, David E; Brown, Jacob L; Rosa, Megan E; Brown, Lemuel A; Perry, Richard A; Henry, Jordyn N; Washington, Tyrone A

    2015-07-01

    Skeletal muscle mitochondrial degeneration is a hallmark of insulin resistance/obesity marked by lost function, enhanced ROS emission, and altered morphology which may be ameliorated by physical activity (PA). However, no prior report has examined mitochondrial quality control regulation throughout biogenesis, fusion/fission dynamics, autophagy, and mitochondrial permeability transition pore (MPTP) in obesity. Therefore, we determined how each process is impacted by Western diet (WD)-induced obesity and whether voluntary PA may alleviate derangements in mitochondrial quality control mechanisms. Despite greater mitochondrial content following WD (COX-IV and Cytochrome C), induction of biogenesis controllers appears impaired (failed induction of PGC-1α). Mitochondrial fusion seems diminished (reduced MFN2, Opa1 proteins), with no significant changes in fission, suggesting a shift in balance of dynamics regulation favoring fission. Autophagy flux was promoted in WD (reduced p62, increased LC3II:I ratio); however, mitophagy marker BNIP3 is reduced in WD which may indicate reduced mitophagy despite enhanced total autophagy flux. MPTP regulator Ant mRNA is reduced by WD. Few processes were impacted by physical activity. Finally, mitochondrial quality control processes are partially promoted by PGC-1α, as PGC-1α transgenic mice display elevated mitochondrial biogenesis and autophagy flux. Additionally, these mice exhibit elevated Mfn1 and Opa1 mRNA, with no change in protein content suggesting these factors are transcriptionally promoted by PGC-1α overexpression. These data demonstrate dysfunctions across mitochondrial quality control in obesity and that PGC-1α is sufficient to promote multiple, but not necessarily all, aspects of mitochondrial quality control. Mitochondrial quality control may therefore be an opportune target to therapeutically treat metabolic disease. PMID:26177961

  10. Controllability of the better chosen partial networks

    NASA Astrophysics Data System (ADS)

    Liu, Xueming; Pan, Linqiang

    2016-08-01

    How to control large complex networks is a great challenge. Recent studies have proved that the whole network can be sufficiently steered by injecting control signals into a minimum set of driver nodes, and the minimum numbers of driver nodes for many real networks are high, indicating that it is difficult to control them. For some large natural and technological networks, it is impossible and not feasible to control the full network. For example, in biological networks like large-scale gene regulatory networks it is impossible to control all the genes. This prompts us to explore the question how to choose partial networks that are easy for controlling and important in networked systems. In this work, we propose a method to achieve this goal. By computing the minimum driver nodes densities of the partial networks of Erdös-Rényi (ER) networks, scale-free (SF) networks and 23 real networks, we find that our method performs better than random method that chooses nodes randomly. Moreover, we find that the nodes chosen by our method tend to be the essential elements of the whole systems, via studying the nodes chosen by our method of a real human signaling network and a human protein interaction network and discovering that the chosen nodes from these networks tend to be cancer-associated genes. The implementation of our method shows some interesting connections between the structure and the controllability of networks, improving our understanding of the control principles of complex systems.

  11. A convex penalty for switching control of partial differential equations

    DOE PAGESBeta

    Clason, Christian; Rund, Armin; Kunisch, Karl; Barnard, Richard C.

    2016-01-19

    A convex penalty for promoting switching controls for partial differential equations is introduced; such controls consist of an arbitrary number of components of which at most one should be simultaneously active. Using a Moreau–Yosida approximation, a family of approximating problems is obtained that is amenable to solution by a semismooth Newton method. In conclusion, the efficiency of this approach and the structure of the obtained controls are demonstrated by numerical examples.

  12. Partial pressure measurements with an active spectrometer

    SciTech Connect

    Brooks, N.H.; Jensen, T.H.; Colchin, R.J.; Maingi, R.; Wade, M.R.; Finkenthal, D.F.; Naumenko, N.; Tugarinov, S.

    1998-07-01

    Partial pressure neutral ga measurements have been made using a commercial Penning gauge in conjunction with an active spectrometer. In prior work utilizing bandpass filters and conventional spectrometers, trace concentrations of the hydrogen isotopes H, D, T and of the noble gases He, Ne and Ar were determined from characteristic spectral lines in the light emitted by the neutral species of these elements. For all the elements mentioned, the sensitivity was limited by spectral contamination from a pervasive background of molecular hydrogen radiation. The active spectrometer overcomes this limitations by means of a digital lock-in method and correlation with reference spectra. Preliminary measurements of an admixture containing a trace amount of neon in deuterium show better than a factor of 20 improvement in sensitivity over conventional techniques. This can be further improved by correlating the relative intensities of multiple lines to sets of reference spectra.

  13. Nested hierarchical controller with partial autonomy

    NASA Technical Reports Server (NTRS)

    Meystel, A.

    1987-01-01

    The problem of computer architecture for intelligent robots with partial autonomy is addressed. A robot with partial autonomy is considered a degenerated case of a fully autonomous robot. Thus, the problem of man-machine communication is formulated, and the conditions are determined for generating a language for such a communication. The duties of the master are determined.

  14. Control of human carnitine palmitoyltransferase II gene transcription by peroxisome proliferator-activated receptor through a partially conserved peroxisome proliferator-responsive element.

    PubMed Central

    Barrero, María J; Camarero, Nuria; Marrero, Pedro F; Haro, Diego

    2003-01-01

    The expression of several genes involved in fatty acid metabolism is regulated by peroxisome proliferator-activated receptors (PPARs). To gain more insight into the control of carnitine palmitoyltransferase (CPT) gene expression, we examined the transcriptional regulation of the human CPT II gene. We show that the 5'-flanking region of this gene is transcriptionally active and binds PPARalpha in vivo in a chromatin immunoprecipitation assay. In addition, we characterized the peroxisome proliferator-responsive element (PPRE) in the proximal promoter of the CPT II gene, which appears to be a novel PPRE. The sequence of this PPRE contains one half-site which is a perfect consensus sequence (TGACCT) but no clearly recognizable second half-site (CAGCAC); this part of the sequence contains only one match to the consensus, which seems to be irrelevant for the binding of PPARalpha. As expected, other members of the nuclear receptor superfamily also bind to this element and repress the activation mediated by PPARalpha, thus showing that the interplay between several nuclear receptors may regulate the entry of fatty acids into the mitochondria, a crucial step in their metabolism. PMID:12408750

  15. Deterministic controlled remote state preparation using partially entangled quantum channel

    NASA Astrophysics Data System (ADS)

    Chen, Na; Quan, Dong Xiao; Yang, Hong; Pei, Chang Xing

    2016-04-01

    In this paper, we propose a novel scheme for deterministic controlled remote state preparation (CRSP) of arbitrary two-qubit states. Suitably chosen partially entangled state is used as the quantum channel. With proper projective measurements carried out by the sender and controller, the receiver can reconstruct the target state by means of appropriate unitary operation. Unit success probability can be achieved for arbitrary two-qubit states. Different from some previous CRSP schemes utilizing partially entangled channels, auxiliary qubit is not required in our scheme. We also show that the success probability is independent of the parameters of the partially entangled quantum channel.

  16. Comparison of several activated partial thromboplastin time methods.

    PubMed

    Morin, R J; Willoughby, D

    1975-08-01

    Activated partial thromboplastin times (APTT's) performed with a semi-automated electrical-conductivity type of clot timer on plasmas from patients with hepatic disease and intravascular coagulation, and on warfarin or heparin therapy, were significantly lower than when done on the same plasmas with either a manual optical method or an automated optical-endpoint instrument. Results of APTT's done on normal plasmas by the three methods were not significantly different. Substitution of different activator-phospholipid reagents resulted in some variability in results, but these differences were less than those between the different done with both the electrical clot timer and the automated optical instrument on prepared plasmas containing 5.0 or 1.0% of factor II, V, VIII, IX, OR X revealed shorter times with the electrical clot timer only in the case of factor II- and factor V-deficient plasmas. APTT's done on normal plasmas to which 0.1 or 0.3 units per ml. of heparin had been added vitro also were shorter with the electrical clot itmer than the automatic optical instrument. Prothrombin times done on normal and abnormal control plasmas and on a series of plasmas from patients on warfarin therapy showed no significant difference between the two methods. PMID:239589

  17. Controlled partial interpenetration in metal-organic frameworks.

    PubMed

    Ferguson, Alan; Liu, Lujia; Tapperwijn, Stefanus J; Perl, David; Coudert, François-Xavier; Van Cleuvenbergen, Stijn; Verbiest, Thierry; van der Veen, Monique A; Telfer, Shane G

    2016-03-01

    Interpenetration, the entwining of multiple lattices, is a common phenomenon in metal-organic frameworks (MOFs). Typically, in interpenetrated MOFs the sub-lattices are fully occupied. Here we report a family of MOFs in which one sub-lattice is fully occupied and the occupancy level of the other can be controlled during synthesis to produce frameworks with variable levels of partial interpenetration. We also report an 'autocatenation' process, a transformation of non-interpenetrated lattices into doubly interpenetrated frameworks via progressively higher degrees of interpenetration that involves no external reagents. Autocatenation maintains crystallinity and can be triggered either thermally or by shear forces. The ligand used to construct these MOFs is chiral, and both racemic and enantiopure partially interpenetrated frameworks can be accessed. X-ray diffraction, nonlinear optical microscopy and theoretical calculations offer insights into the structures and dynamic behaviour of these materials and the growth mechanisms of interpenetrated MOFs. PMID:26892557

  18. Controlled partial interpenetration in metal-organic frameworks

    NASA Astrophysics Data System (ADS)

    Ferguson, Alan; Liu, Lujia; Tapperwijn, Stefanus J.; Perl, David; Coudert, François-Xavier; van Cleuvenbergen, Stijn; Verbiest, Thierry; van der Veen, Monique A.; Telfer, Shane G.

    2016-03-01

    Interpenetration, the entwining of multiple lattices, is a common phenomenon in metal-organic frameworks (MOFs). Typically, in interpenetrated MOFs the sub-lattices are fully occupied. Here we report a family of MOFs in which one sub-lattice is fully occupied and the occupancy level of the other can be controlled during synthesis to produce frameworks with variable levels of partial interpenetration. We also report an ‘autocatenation’ process, a transformation of non-interpenetrated lattices into doubly interpenetrated frameworks via progressively higher degrees of interpenetration that involves no external reagents. Autocatenation maintains crystallinity and can be triggered either thermally or by shear forces. The ligand used to construct these MOFs is chiral, and both racemic and enantiopure partially interpenetrated frameworks can be accessed. X-ray diffraction, nonlinear optical microscopy and theoretical calculations offer insights into the structures and dynamic behaviour of these materials and the growth mechanisms of interpenetrated MOFs.

  19. A double-blind, placebo-controlled, randomized clinical trial of recombinant human chorionic gonadotropin on muscle strength and physical function and activity in older men with partial age-related androgen deficiency.

    PubMed

    Liu, Peter Y; Wishart, Susan M; Handelsman, David J

    2002-07-01

    Despite partial androgen deficiency, the safety and efficacy of androgen therapy in older men remains controversial because controlled studies of testosterone have given equivocal results. Human chorionic gonadotropin (hCG) can be conveniently and infrequently self-administered, and it increases not only circulating testosterone but also estradiol and other testicular steroids. We evaluated the efficacy and safety of 3 months of treatment with sc recombinant hCG (r-hCG, Ovidrel) on muscle mass, strength, mobility, and physical activity in ambulant, community-dwelling men more than 60 yr old having partial androgen deficiency (testosterone < or = 15 nmol/liter, twice). Forty eligible men (mean age, 67 yr; range, 60-85 yr) were randomized to receive r-hCG (5000 IU, 250 microg) or placebo by twice weekly sc self-injection and were studied before treatment, monthly during treatment, and 1 month after treatment. All completed the study, and treatment groups were well matched. r-hCG significantly increased body weight (approximately 1 kg; P < 0.05) and lean body mass ( approximately 2 kg; P < 0.001) and reduced fat mass (approximately 1 kg, P < 0.05). However, anthropometric measures of skinfold thickness (biceps, triceps, subscapular, suprailiac) and circumferences (midarm, waist, hip, and midthigh), including the waist-hip ratio, did not change significantly. Shoulder and knee strength (peak torque), as measured by isokinetic and isometric dynamometry, was not significantly increased, nor was physical activity (accelerometry and Physical Activity Scale for Elderly self-report) or gait and balance (modified Guralnik and Frailty and Injuries: Cooperative Studies of Intervention Techniques performance batteries) altered. Total and free testosterone and estradiol were markedly (150%; P < 0.001) and stably increased, whereas LH, FSH, and urea were significantly decreased. Testis volume was significantly decreased (approximately 5 ml; P < 0.05). There were no significant

  20. Neuronal Activity in the Subthalamic Cerebrovasodilator Area under Partial-Gravity Conditions in Rats

    PubMed Central

    Zeredo, Jorge L.; Toda, Kazuo; Kumei, Yasuhiro

    2014-01-01

    The reduced-gravity environment in space is known to cause an upward shift in body fluids and thus require cardiovascular adaptations in astronauts. In this study, we recorded in rats the neuronal activity in the subthalamic cerebrovasodilator area (SVA), a key area that controls cerebral blood flow (CBF), in response to partial gravity. “Partial gravity” is the term that defines the reduced-gravity levels between 1 g (the unit gravity acceleration on Earth) and 0 g (complete weightlessness in space). Neuronal activity was recorded telemetrically through chronically implanted microelectrodes in freely moving rats. Graded levels of partial gravity from 0.4 g to 0.01 g were generated by customized parabolic-flight maneuvers. Electrophysiological signals in each partial-gravity phase were compared to those of the preceding 1 g level-flight. As a result, SVA neuronal activity was significantly inhibited by the partial-gravity levels of 0.15 g and lower, but not by 0.2 g and higher. Gravity levels between 0.2–0.15 g could represent a critical threshold for the inhibition of neurons in the rat SVA. The lunar gravity (0.16 g) might thus trigger neurogenic mechanisms of CBF control. This is the first study to examine brain electrophysiology with partial gravity as an experimental parameter. PMID:25370031

  1. Neuronal Activity in the Subthalamic Cerebrovasodilator Area under Partial-Gravity Conditions in Rats.

    PubMed

    Zeredo, Zeredo L; Toda, Kazuo; Kumei, Yasuhiro

    2014-01-01

    The reduced-gravity environment in space is known to cause an upward shift in body fluids and thus require cardiovascular adaptations in astronauts. In this study, we recorded in rats the neuronal activity in the subthalamic cerebrovasodilator area (SVA), a key area that controls cerebral blood flow (CBF), in response to partial gravity. "Partial gravity" is the term that defines the reduced-gravity levels between 1 g (the unit gravity acceleration on Earth) and 0 g (complete weightlessness in space). Neuronal activity was recorded telemetrically through chronically implanted microelectrodes in freely moving rats. Graded levels of partial gravity from 0.4 g to 0.01 g were generated by customized parabolic-flight maneuvers. Electrophysiological signals in each partial-gravity phase were compared to those of the preceding 1 g level-flight. As a result, SVA neuronal activity was significantly inhibited by the partial-gravity levels of 0.15 g and lower, but not by 0.2 g and higher. Gravity levels between 0.2-0.15 g could represent a critical threshold for the inhibition of neurons in the rat SVA. The lunar gravity (0.16 g) might thus trigger neurogenic mechanisms of CBF control. This is the first study to examine brain electrophysiology with partial gravity as an experimental parameter. PMID:25370031

  2. Neural network guided search control in partial order planning

    SciTech Connect

    Zimmerman, T.

    1996-12-31

    The development of efficient search control methods is an active research topic in the field of planning. Investigation of a planning program integrated with a neural network (NN) that assists in search control is underway, and has produced promising preliminary results.

  3. Measurement and Control of Oxygen Partial Pressure in an Electrostatic Levitator

    NASA Technical Reports Server (NTRS)

    SanSoucie, Michael P.; Rogers, Jan R.

    2014-01-01

    Recently the NASA Marshall Space Flight Center electrostatic levitation (ESL) laboratory has been upgraded to include an oxygen control system. This system allows the oxygen partial pressure within the vacuum chamber to be measured and controlled, at elevated temperatures, theoretically in the range from 10(exp -36) to 10(exp 0) bar. The role of active surface agents in liquid metals is fairly well known; however, published surface tension data typically has large scatter, which has been hypothesized to be caused by the presence of oxygen. The surface tension of metals is affected by even a small amount of adsorption of oxygen. It has even been shown that oxygen partial pressures may need to be as low as 10(exp -24) bar to avoid oxidation. While electrostatic levitation is done under high vacuum, oxide films or dissolved oxygen may have significant effects on materials properties, such as surface tension and viscosity. Therefore, the ability to measure and control the oxygen partial pressure within the chamber is highly desirable. The oxygen control system installed at MSFC contains a potentiometric sensor, which measures the oxygen partial pressure, and an oxygen ion pump. In the pump, a pulse-width modulated electric current is applied to yttrium-stabilized zirconia, resulting in oxygen transfer into or out of the system. Also part of the system is a control unit, which consists of temperature controllers for the sensor and pump, PID-based current loop for the ion pump, and a control algorithm. This system can be used to study the effects of oxygen on the thermophysical properties of metals, ceramics, glasses, and alloys. It can also be used to provide more accurate measurements by processing the samples at very low oxygen partial pressures. The oxygen control system will be explained in more detail and an overview of its use and limitations in an electrostatic levitator will be described. Some preliminary measurements have been made, and the results to date will

  4. Model-based control of thermoacoustic instabilities in partially premixed lean combustion - a design case study

    NASA Astrophysics Data System (ADS)

    Yuan, Xiao-Chuan; Glover, Keith

    2013-11-01

    Self-excited oscillation is becoming a major issue in low-emission, lean partially premixed combustion systems, and active control has been shown to be a feasible method to suppress such instabilities. A number of robust control methods are employed to obtain a feedback controller and it is observed that the robustness to system uncertainty is significantly better for a low complexity controller in spite of the norms being similar. Moreover, we demonstrate that closed-loop stability for such a complex system can be proved via use of the integral quadratic constraint method. Open- and closed-loop nonlinear simulations are provided.

  5. Robust Dynamics and Control of a Partially Observed Markov Chain

    SciTech Connect

    Elliott, R. J. Malcolm, W. P. Moore, J. P.

    2007-12-15

    In a seminal paper, Martin Clark (Communications Systems and Random Process Theory, Darlington, 1977, pp. 721-734, 1978) showed how the filtered dynamics giving the optimal estimate of a Markov chain observed in Gaussian noise can be expressed using an ordinary differential equation. These results offer substantial benefits in filtering and in control, often simplifying the analysis and an in some settings providing numerical benefits, see, for example Malcolm et al. (J. Appl. Math. Stoch. Anal., 2007, to appear).Clark's method uses a gauge transformation and, in effect, solves the Wonham-Zakai equation using variation of constants. In this article, we consider the optimal control of a partially observed Markov chain. This problem is discussed in Elliott et al. (Hidden Markov Models Estimation and Control, Applications of Mathematics Series, vol. 29, 1995). The innovation in our results is that the robust dynamics of Clark are used to compute forward in time dynamics for a simplified adjoint process. A stochastic minimum principle is established.

  6. Voltage is a partial activator of rat thermosensitive TRP channels

    PubMed Central

    Matta, José A; Ahern, Gerard P

    2007-01-01

    TRPV1 and TRPM8 are sensory nerve ion channels activated by heating and cooling, respectively. A variety of physical and chemical stimuli activate these receptors in a synergistic manner but the underlying mechanisms are unclear. Both channels are voltage sensitive, and temperature and ligands modulate this voltage dependence. Thus, a voltage-sensing mechanism has become an attractive model to explain the generalized gating of these and other thermo-sensitive TRP channels. We show here using whole-cell and single channel measurements that voltage produces only a partial activation of TRPV1 and TRPM8. At room temperature (20–25°C) membrane depolarization evokes responses that saturate at ∼50–60% of the maximum open probability. Furthermore, high concentrations of capsaicin (10 μm), resiniferatoxin (5 μm) and menthol (6 mm) reveal voltage-independent gating. Similarly, other modes of TRPV1 regulation including heat, protein kinase C-dependent phosphorylation, and protons enhance both the efficacy and sensitivity of voltage activation. In contrast, the TRPV1 antagonist capsazepine produces the opposite effects. These data can be explained by an allosteric model in which voltage, temperature, agonists and inverse agonists are independently coupled, either positively or negatively, to channel gating. Thus, voltage acts separately but in concert with other stimuli to regulate channel activation, and, therefore, a voltage-sensitive mechanism is unlikely to represent a final, gating mechanism for these channels. PMID:17932142

  7. Active controls technology to maximize structural efficiency

    NASA Technical Reports Server (NTRS)

    Hoy, J. M.; Arnold, J. M.

    1978-01-01

    The implication of the dependence on active controls technology during the design phase of transport structures is considered. Critical loading conditions are discussed along with probable ways of alleviating these loads. Why fatigue requirements may be critical and can only be partially alleviated is explained. The significance of certain flutter suppression system criteria is examined.

  8. Further Results on Finite-Time Partial Stability and Stabilization. Applications to Nonlinear Control Systems

    SciTech Connect

    Jammazi, Chaker

    2009-03-05

    The paper gives Lyapunov type sufficient conditions for partial finite-time and asymptotic stability in which some state variables converge to zero while the rest converge to constant values that possibly depend on the initial conditions. The paper then presents partially asymptotically stabilizing controllers for many nonlinear control systems for which continuous asymptotically stabilizing (in the usual sense) controllers are known not to exist.

  9. Controlled Teleportation of a Qudit State by Partially Entangled GHZ States

    NASA Astrophysics Data System (ADS)

    Wang, Jin-wei; Shu, Lan; Mo, Zhi-wen; Zhang, Zhi-hua

    2014-08-01

    In this paper, we propose a controlled teleportation scheme which communicates an arbitrary ququart state via two sets of partially entangled GHZ state. The necessary measurements and operations are given detailedly. Furthmore the scheme is generalized to teleport a qudit state via s sets of partially entangled GHZ state.

  10. Immunomodulatory activity and partial characterisation of polysaccharides from Momordica charantia.

    PubMed

    Deng, Yuan-Yuan; Yi, Yang; Zhang, Li-Fang; Zhang, Rui-Fen; Zhang, Yan; Wei, Zhen-Cheng; Tang, Xiao-Jun; Zhang, Ming-Wei

    2014-01-01

    Momordica charantia Linn. is used as an edible and medicinal vegetable in sub-tropical areas. Until now, studies on its composition and related activities have been confined to compounds of low molecular mass, and no data have been reported concerning the plant's polysaccharides. In this work, a crude polysaccharide of M. charantia (MCP) fruit was isolated by hot water extraction and then purified using DEAE-52 cellulose anion-exchange chromatography to produce two main fractions MCP1 and MCP2. The immunomodulatory effects and physicochemical characteristics of these fractions were investigated in vitro and in vivo. The results showed that intragastric administration of 150 or 300 mg·kg-·d⁻¹ of MCP significantly increased the carbolic particle clearance index, serum haemolysin production, spleen index, thymus index and NK cell cytotoxicity to normal control levels in cyclophosphamide (Cy)-induced immunosuppressed mice. Both MCP1 and MCP2 effectively stimulated normal and concanavalin A-induced splenic lymphocyte proliferation in vitro at various doses. The average molecular weights of MCP1 and MCP2, which were measured using high-performance gel permeation chromatography, were 8.55×10⁴ Da and 4.41×10⁵ Da, respectively. Both fractions exhibited characteristic polysaccharide bands in their Fourier transform infrared spectrum. MCP1 is mainly composed of glucose and galactose, and MCP2 is mainly composed of glucose, mannose and galactose. The results indicate that MCP and its fractions have good potential as immunotherapeutic adjuvants. PMID:25178064

  11. TMJ function after partial condylectomy in active mandibular condylar hyperplasia

    PubMed Central

    Olate, Sergio; Martinez, Felipe; Uribe, Francisca; Pozzer, Leandro; Cavalieri-Pereira, Lucas; de Moraes, Marcio

    2014-01-01

    Condylar hyperplasia is a frequent pathology that causes severe facial asymmetries. The partial condylectomy generally halts the disease. The aim of this research was to examine post-condylectomy TMJ function; 14 patients were included in this study, 6 male and 8 female. The average age was 21 years old. In all, the partial condylectomy was performed with preauricular or endaural access and the osteotomy were performed with drills, saw or an ultrasonic system. The patients were assessed with 3 or more time after surgery and were considering maximum mouth opening, right and left lateralities, presence of pain, noises, alterations in the facial nerve (VII) and esthetic alteration from the scar. The analysis was performed with the visual analog scale (VAS) and with a 7 cm metallic rule. Data analysis was descriptive plus chi-square test considering p value < 0.05 for statistical differences. With an average of 11 month after surgery, the results showed that the open mouth (over 35 mm) and lateralities (average 9 mm for the both right and left side) were normal and without statistical differences between the right or left side. Noise was observed in 3 patients and pain was observed in two patients with level 2 and 1 (VAS score). Scar was not related to problem with patient and the temporal branch of facial nerve was observed with limitations but without problem for patients. It can be concluded that the condylectomy is a safe and effective procedure with low morbidity for patients. PMID:24753777

  12. Theoretical analysis of controllability of interference phenomena between partially coherent fields in the intensity matrix theory

    NASA Astrophysics Data System (ADS)

    Yashiki, Satoshi

    2016-09-01

    We analyze the controllability of interference phenomena between partially coherent fields by introducing the Wigner distribution function (WDF) and entropy, which is defined using the intensity matrix [H. Gamo, J. Opt. Soc. Am. 47, 976 (1957)]. The analytical derivation of the WDF and entropy is presented for a partially coherent imaging system consisting of two pinholes illuminated by a circular source. It is shown that the WDF, defined in the 4D space–spatial frequency region, and entropy can be useful tools to understand how one can freely and quantitatively control the interference when any optical components in the partially coherent imaging system are changed.

  13. Strategies for Controlling Item Exposure in Computerized Adaptive Testing with the Generalized Partial Credit Model

    ERIC Educational Resources Information Center

    Davis, Laurie Laughlin

    2004-01-01

    Choosing a strategy for controlling item exposure has become an integral part of test development for computerized adaptive testing (CAT). This study investigated the performance of six procedures for controlling item exposure in a series of simulated CATs under the generalized partial credit model. In addition to a no-exposure control baseline…

  14. Statechart-based design controllers for FPGA partial reconfiguration

    NASA Astrophysics Data System (ADS)

    Łabiak, Grzegorz; Wegrzyn, Marek; Rosado Muñoz, Alfredo

    2015-09-01

    Statechart diagram and UML technique can be a vital part of early conceptual modeling. At the present time there is no much support in hardware design methodologies for reconfiguration features of reprogrammable devices. Authors try to bridge the gap between imprecise UML model and formal HDL description. The key concept in author's proposal is to describe the behavior of the digital controller by statechart diagrams and to map some parts of the behavior into reprogrammable logic by means of group of states which forms sequential automaton. The whole process is illustrated by the example with experimental results.

  15. Stochastic optimal control of partially observable nonlinear quasi-integrable Hamiltonian systems

    NASA Astrophysics Data System (ADS)

    Feng, Ju; Zhu, Weiqiu; Ying, Zuguang

    2010-01-01

    The stochastic optimal control of partially observable nonlinear quasi-integrable Hamiltonian systems is investigated. First, the stochastic optimal control problem of a partially observable nonlinear quasi-integrable Hamiltonian system is converted into that of a completely observable linear system based on a theorem due to Charalambous and Elliot. Then, the converted stochastic optimal control problem is solved by applying the stochastic averaging method and the stochastic dynamical programming principle. The response of the controlled quasi Hamiltonian system is predicted by solving the averaged Fokker-Planck-Kolmogorov equation and the Riccati equation for the estimated error of system states. As an example to illustrate the procedure and effectiveness of the proposed method, the stochastic optimal control problem of a partially observable two-degree-of-freedom quasi-integrable Hamiltonian system is worked out in detail.

  16. Multi-input partial eigenvalue assignment for high order control systems with time delay

    NASA Astrophysics Data System (ADS)

    Zhang, Lei

    2016-05-01

    In this paper, we consider the partial eigenvalue assignment problem for high order control systems with time delay. Ram et al. (2011) [1] have shown that a hybrid method can be used to solve partial quadratic eigenvalue assignment problem of single-input vibratory system. Based on this theory, a rather simple algorithm for solving multi-input partial eigenvalue assignment for high order control systems with time delay is proposed. Our method can assign the expected eigenvalues and keep the no spillover property. The solution can be implemented with only partial information of the eigenvalues and the corresponding eigenvectors of the matrix polynomial. Numerical examples are given to illustrate the efficiency of our approach.

  17. Multi-strategy learning of search control for partial-order planning

    SciTech Connect

    Estlin, T.A.; Mooney, R.J.

    1996-12-31

    Most research in planning and learning has involved linear, state-based planners. This paper presents SCOPE, a system for learning search-control rules that improve the performance of a partial-order planner. SCOPE integrates explanation-based and inductive learning techniques to acquire control rules for a partial-order planner. Learned rules are in the form of selection heuristics that help the planner choose between competing plan refinements. Specifically, SCOPE learns domain-specific control rules for a version of the UCPOP planning algorithm. The resulting system is shown to produce significant speedup in two different planning domains.

  18. Detecting and correcting partial errors: Evidence for efficient control without conscious access.

    PubMed

    Rochet, N; Spieser, L; Casini, L; Hasbroucq, T; Burle, B

    2014-09-01

    Appropriate reactions to erroneous actions are essential to keeping behavior adaptive. Erring, however, is not an all-or-none process: electromyographic (EMG) recordings of the responding muscles have revealed that covert incorrect response activations (termed "partial errors") occur on a proportion of overtly correct trials. The occurrence of such "partial errors" shows that incorrect response activations could be corrected online, before turning into overt errors. In the present study, we showed that, unlike overt errors, such "partial errors" are poorly consciously detected by participants, who could report only one third of their partial errors. Two parameters of the partial errors were found to predict detection: the surface of the incorrect EMG burst (larger for detected) and the correction time (between the incorrect and correct EMG onsets; longer for detected). These two parameters provided independent information. The correct(ive) responses associated with detected partial errors were larger than the "pure-correct" ones, and this increase was likely a consequence, rather than a cause, of the detection. The respective impacts of the two parameters predicting detection (incorrect surface and correction time), along with the underlying physiological processes subtending partial-error detection, are discussed. PMID:24347086

  19. A Comparison of Item Exposure Control Procedures with the Generalized Partial Credit Model

    ERIC Educational Resources Information Center

    Sanchez, Edgar Isaac

    2008-01-01

    To enhance test security of high stakes tests, it is vital to understand the way various exposure control strategies function under various IRT models. To that end the present dissertation focused on the performance of several exposure control strategies under the generalized partial credit model with an item pool of 100 and 200 items. These…

  20. On stochastic optimal control of partially observable nonlinear quasi Hamiltonian systems.

    PubMed

    Zhu, Wei-qiu; Ying, Zu-guang

    2004-11-01

    A stochastic optimal control strategy for partially observable nonlinear quasi Hamiltonian systems is proposed. The optimal control forces consist of two parts. The first part is determined by the conditions under which the stochastic optimal control problem of a partially observable nonlinear system is converted into that of a completely observable linear system. The second part is determined by solving the dynamical programming equation derived by applying the stochastic averaging method and stochastic dynamical programming principle to the completely observable linear control system. The response of the optimally controlled quasi Hamiltonian system is predicted by solving the averaged Fokker-Planck-Kolmogorov equation associated with the optimally controlled completely observable linear system and solving the Riccati equation for the estimated error of system states. An example is given to illustrate the procedure and effectiveness of the proposed control strategy. PMID:15495321

  1. A stochastic optimal control strategy for partially observable nonlinear quasi-Hamiltonian systems

    NASA Astrophysics Data System (ADS)

    Ying, Z. G.; Zhu, W. Q.

    2008-02-01

    A stochastic optimal control strategy for partially observable nonlinear quasi-Hamiltonian systems is proposed. The optimal control force consists of two parts. The first part is determined by the conditions under which the stochastic optimal control problem of a partially observable nonlinear system is converted into that of a completely observable linear system. The second part is determined by solving the dynamical programming equation derived by applying the stochastic averaging method and stochastic dynamical programming principle to the completely observable linear control system. The response of the optimally controlled quasi-Hamiltonian system is predicted by solving the averaged Fokker-Planck-Kolmogorov equation associated with the optimally controlled completely observable linear system and solving the Riccati equation for the estimate errors of system states. An example is given to illustrate the procedure and effectiveness of the proposed control strategy.

  2. Mnemonic strategy training partially restores hippocampal activity in patients with mild cognitive impairment

    PubMed Central

    Hampstead, Benjamin M.; Stringer, Anthony Y.; Stilla, Randall F.; Giddens, Michelle; Sathian, K.

    2012-01-01

    Learning and memory deficits typify patients with mild cognitive impairment (MCI) and are generally attributed to medial temporal lobe dysfunction. Although the hippocampus is perhaps the most commonly studied neuroanatomical structure in these patients, there have been few attempts to identify rehabilitative interventions that facilitate its functioning. Here, we present results from a randomized, controlled, single-blind study in which patients with MCI and healthy elderly controls (HEC) were randomized to either 3 sessions of mnemonic strategy training (MS) or a matched-exposure control group (XP). All participants underwent pre- and post-training fMRI scanning as they encoded and retrieved object-location associations. For the current report, fMRI analyses were restricted to the hippocampus, as defined anatomically. Before training, MCI patients showed reduced hippocampal activity during both encoding and retrieval, relative to HEC. Following training, the MCI MS group demonstrated increased activity during both encoding and retrieval. There were significant differences between the MCI MS and MCI XP groups during retrieval, especially within the right hippocampus. Thus, MS facilitated hippocampal functioning in a partially restorative manner. We conclude that cognitive rehabilitation techniques may help mitigate hippocampal dysfunction in MCI patients. PMID:22368035

  3. Allosteric activation of the Par-6 PDZ via a partial unfolding transition

    PubMed Central

    Whitney, Dustin S.; Peterson, Francis C.; Kovrigin, Evgenii L.; Volkman, Brian F.

    2013-01-01

    Proteins exist in a delicate balance between the native and unfolded states, where thermodynamic stability may be sacrificed to attain the flexibility required for efficient catalysis, binding or allosteric control. Par-6 regulates the Par polarity complex by transmitting a GTPase signal through the CRIB-PDZ module that alters PDZ lig-and binding. Allosteric activation of the PDZ is achieved by local rearrangement of the L164 and K165 side chains to stabilize the interdomain CRIB-PDZ interface and reposition a conserved element of the ligand binding pocket. However, microsecond to millisecond dynamics measurements revealed that L164/K165 exchange requires a larger rearrangement than expected. The margin of thermodynamic stability for the PDZ domain is modest (~3 kcal/mol) and further reduced by transient interactions with the disordered CRIB domain. Measurements of local structural stability revealed that tertiary contacts within the PDZ are disrupted by a partial unfolding transition that enables interconversion of the L/K switch. The unexpected participation of partial PDZ unfolding in the allosteric mechanism of Par-6 suggests that native-state unfolding may be essential for the function of other marginally stable proteins. PMID:23705660

  4. Realizing Open-Destination and Controlled Teleportation of a Rotation Using Partially Entangled Pairs

    NASA Astrophysics Data System (ADS)

    Chen, Li-Bing; Jin, Rui-Bo; Peng, Tan; Lu, Hong

    We present a scheme for realizing open-destination and controlled teleportation of a single-qubit rotation gate, albeit probabilistically, by using partially entangled pairs of particles. In the scheme, a quantum rotation is faithfully teleported onto any one of N spatially separated receivers under the control of the (N-1) unselected receivers in a network. We first present the three-destination and controlled teleportation of a rotation gate by using three partially entangled pairs, and then generalize the scheme to the case of N-destination. In our scheme, the sender's local generalized measurement described by a positive operator-valued measurement (POVM) lies at the heart. We construct the required POVM. The fact that deterministic and exact teleportation of a rotation gate could be realized using partially entangled pairs is notable.

  5. Camera Based Closed Loop Control for Partial Penetration Welding of Overlap Joints

    NASA Astrophysics Data System (ADS)

    Abt, F.; Heider, A.; Weber, R.; Graf, T.; Blug, A.; Carl, D.; Höfler, H.; Nicolosi, L.; Tetzlaff, R.

    Welding of overlap joints with partial penetration in automotive applications is a challenging process, since the laser power must be set very precisely to achieve a proper connection between the two joining partners without damaging the backside of the sheet stack. Even minor changes in welding conditions can lead to bad results. To overcome this problem a camera based closed loop control for partial penetration welding of overlap joints was developed. With this closed loop control it is possible to weld such configurations with a stable process result even under changing welding conditions.

  6. Selectively active markers for solving of the partial occlusion problem in matchmoving and chromakeying workflow

    NASA Astrophysics Data System (ADS)

    Mazurek, Przemysław

    2013-09-01

    Matchmoving (Match Moving) is the process used for the estimation of camera movements for further integration of acquired video image with computer graphics. The estimation of movements is possible using pattern recognition, 2D and 3D tracking algorithms. The main problem for the workflow is the partial occlusion of markers by the actor, because manual rotoscoping is necessary for fixing of the chroma-keyed footage. In the paper, the partial occlusion problem is solved using the invented, selectively active electronic markers. The sensor network with multiple infrared links detects occlusion state (no-occlusion, partial, full) and switch LED's based markers.

  7. Instrument for stable high temperature Seebeck coefficient and resistivity measurements under controlled oxygen partial pressure

    SciTech Connect

    Ihlefeld, Jon F.; Brown-Shaklee, Harlan James; Sharma, Peter Anand

    2015-04-28

    The transport properties of ceramic materials strongly depend on oxygen activity, which is tuned by changing the partial oxygen pressure (pO2) prior to and during measurement. Within, we describe an instrument for highly stable measurements of Seebeck coefficient and electrical resistivity at temperatures up to 1300 K with controlled oxygen partial pressure. An all platinum construction is used to avoid potential materials instabilities that can cause measurement drift. Two independent heaters are employed to establish a small temperature gradient for Seebeck measurements, while keeping the average temperature constant and avoiding errors associated with pO2-induced drifts in thermocouple readings. Oxygen equilibrium is monitored using both an O2 sensor and the transient behavior of the resistance as a proxy. A pO2 range of 10-25–100 atm can be established with appropriate gas mixtures. Seebeck measurements were calibrated against a high purity platinum wire, Pt/Pt–Rh thermocouple wire, and a Bi2Te3 Seebeck coefficient Standard Reference Material. To demonstrate the utility of this instrument for oxide materials we present measurements as a function of pO2 on a 1 % Nb-doped SrTiO3 single crystal, and show systematic changes in properties consistent with oxygen vacancy defect chemistry. Thus, an approximately 11% increase in power factor over a pO2 range of 10-19–10-8 atm at 973 K for the donor-doped single crystals is observed.

  8. Instrument for stable high temperature Seebeck coefficient and resistivity measurements under controlled oxygen partial pressure

    DOE PAGESBeta

    Ihlefeld, Jon F.; Brown-Shaklee, Harlan James; Sharma, Peter Anand

    2015-04-28

    The transport properties of ceramic materials strongly depend on oxygen activity, which is tuned by changing the partial oxygen pressure (pO2) prior to and during measurement. Within, we describe an instrument for highly stable measurements of Seebeck coefficient and electrical resistivity at temperatures up to 1300 K with controlled oxygen partial pressure. An all platinum construction is used to avoid potential materials instabilities that can cause measurement drift. Two independent heaters are employed to establish a small temperature gradient for Seebeck measurements, while keeping the average temperature constant and avoiding errors associated with pO2-induced drifts in thermocouple readings. Oxygen equilibriummore » is monitored using both an O2 sensor and the transient behavior of the resistance as a proxy. A pO2 range of 10-25–100 atm can be established with appropriate gas mixtures. Seebeck measurements were calibrated against a high purity platinum wire, Pt/Pt–Rh thermocouple wire, and a Bi2Te3 Seebeck coefficient Standard Reference Material. To demonstrate the utility of this instrument for oxide materials we present measurements as a function of pO2 on a 1 % Nb-doped SrTiO3 single crystal, and show systematic changes in properties consistent with oxygen vacancy defect chemistry. Thus, an approximately 11% increase in power factor over a pO2 range of 10-19–10-8 atm at 973 K for the donor-doped single crystals is observed.« less

  9. Active control of convection

    SciTech Connect

    Bau, H.H.

    1995-12-31

    Using stability theory, numerical simulations, and in some instances experiments, it is demonstrated that the critical Rayleigh number for the bifurcation (1) from the no-motion (conduction) state to the motion state and (2) from time-independent convection to time-dependent, oscillatory convection in the thermal convection loop and Rayleigh-Benard problems can be significantly increased or decreased. This is accomplished through the use of a feedback controller effectuating small perturbations in the boundary data. The controller consists of sensors which detect deviations in the fluid`s temperature from the motionless, conductive values and then direct actuators to respond to these deviations in such a way as to suppress the naturally occurring flow instabilities. Actuators which modify the boundary`s temperature/heat flux are considered. The feedback controller can also be used to control flow patterns and generate complex dynamic behavior at relatively low Rayleigh numbers.

  10. A Robust Reinforcement Learning Control Design Method for Nonlinear System with Partially Unknown Structure

    NASA Astrophysics Data System (ADS)

    Nakano, Kazuhiro; Obayashi, Masanao; Kuremoto, Takashi; Kobayashi, Kunikazu

    We propose a robust control system which has robustness for disturbance and can deal with a nonlinear system with partially unknown structure by fusing reinforcement learning and robust control theory. First, we solved an optimal control problem without using unknown part of functions of the system, using neural network and the repetition learning of reinforcement learning algorithm. Second, we built the robust reinforcement learning control system which permits uncertainty and has robustness for disturbance by fusing the idea of H infinity control theory with above system.

  11. Mex3c mutation reduces adiposity partially through increasing physical activity.

    PubMed

    Han, Changjie; Jiao, Yan; Zhao, Qingguo; Lu, Baisong

    2014-06-01

    MEX3C is an RNA-binding protein with unknown physiological function. We have recently reported that a Mex3c mutation in mice causes growth retardation and reduced adiposity, but how adiposity is reduced remains unclear. Herein, we show that homozygous Mex3c gene trap mice have increased physical activity. The Mex3c mutation consistently conferred full protection from diet-induced obesity, hyperglycemia, insulin resistance, hyperlipidemia, and hepatic steatosis. In ob/ob mice with leptin deficiency, the Mex3c mutation also increased physical activity and improved glucose and lipid profiles. Expressing cre in the neurons of Mex3c gene trap mice, an attempt to partially restoring neuronal Mex3c expression, significantly increased white adipose tissue deposition, but had no effects on body length. Our data suggest that one way in which Mex3c regulates adiposity is through controlling physical activity, and that neuronal Mex3c expression could play an important role in this process. PMID:24741071

  12. Efficient All-Vacuum Deposited Perovskite Solar Cells by Controlling Reagent Partial Pressure in High Vacuum.

    PubMed

    Hsiao, Sheng-Yi; Lin, Hong-Lin; Lee, Wei-Hung; Tsai, Wei-Lun; Chiang, Kai-Ming; Liao, Wei-Yu; Ren-Wu, Chen-Zheng; Chen, Chien-Yu; Lin, Hao-Wu

    2016-08-01

    All-vacuum-deposited perovskite solar cells produced by controlling reagent partial pressure in high vacuum with newly developed multi-layer electron and hole transporting structures show outstanding power conversion efficiency of 17.6% and smooth, pinhole-free, micrometer-sized perovskite crystal grains. PMID:27226143

  13. An approximation theory for nonlinear partial differential equations with applications to identification and control

    NASA Technical Reports Server (NTRS)

    Banks, H. T.; Kunisch, K.

    1982-01-01

    Approximation results from linear semigroup theory are used to develop a general framework for convergence of approximation schemes in parameter estimation and optimal control problems for nonlinear partial differential equations. These ideas are used to establish theoretical convergence results for parameter identification using modal (eigenfunction) approximation techniques. Results from numerical investigations of these schemes for both hyperbolic and parabolic systems are given.

  14. Application of partial differential equation modeling of the control/structural dynamics of flexible spacecraft

    NASA Technical Reports Server (NTRS)

    Taylor, Lawrence W., Jr.; Rajiyah, H.

    1991-01-01

    Partial differential equations for modeling the structural dynamics and control systems of flexible spacecraft are applied here in order to facilitate systems analysis and optimization of these spacecraft. Example applications are given, including the structural dynamics of SCOLE, the Solar Array Flight Experiment, the Mini-MAST truss, and the LACE satellite. The development of related software is briefly addressed.

  15. Takagi-Sugeno fuzzy modeling and chaos control of partial differential systems.

    PubMed

    Vasegh, Nastaran; Khellat, Farhad

    2013-12-01

    In this paper a unified approach is presented for controlling chaos in nonlinear partial differential systems by a fuzzy control design. First almost all known chaotic partial differential equation systems are represented by Takagi-Sugeno fuzzy model. For investigating design procedure, Kuramoto-Sivashinsky (K-S) equation is selected. Then, all linear subsystems of K-S equation are transformed to ordinary differential equation (ODE) systems by truncated Fourier series of sine-cosine functions. By solving Riccati equation for each ODE systems, parallel stabilizing feedback controllers are determined. Finally, a distributed fuzzy feedback for K-S equation is designed. Numerical simulations are given to show that the distributed fuzzy controller is very easy to design, efficient, and capable to extend. PMID:24387539

  16. Active weld control

    NASA Technical Reports Server (NTRS)

    Powell, Bradley W.; Burroughs, Ivan A.

    1994-01-01

    Through the two phases of this contract, sensors for welding applications and parameter extraction algorithms have been developed. These sensors form the foundation of a weld control system which can provide action weld control through the monitoring of the weld pool and keyhole in a VPPA welding process. Systems of this type offer the potential of quality enhancement and cost reduction (minimization of rework on faulty welds) for high-integrity welding applications. Sensors for preweld and postweld inspection, weld pool monitoring, keyhole/weld wire entry monitoring, and seam tracking were developed. Algorithms for signal extraction were also developed and analyzed to determine their application to an adaptive weld control system. The following sections discuss findings for each of the three sensors developed under this contract: (1) weld profiling sensor; (2) weld pool sensor; and (3) stereo seam tracker/keyhole imaging sensor. Hardened versions of these sensors were designed and built under this contract. A control system, described later, was developed on a multiprocessing/multitasking operating system for maximum power and flexibility. Documentation for sensor mechanical and electrical design is also included as appendices in this report.

  17. Active Control of Engine Dynamics

    NASA Astrophysics Data System (ADS)

    2002-11-01

    Active control can alleviate design constraints and improve the response to operational requirements in gas turbines. The Course presented the state-of-the-art including experimental, theoretical knowledge and practical information. Topics treated: stability characteristics; active control approaches; robustness and fundamental limits; combustion systems processes; combustor dynamics; compression system dynamics models; diagnostics and control of compression instabilities; sensor and actuator architectures; R&D needs of future prospects. The course has shown that for combustion systems, as well as in actuator and sensor technologies the active control approach is a viable option even at full scale with potential for aero engines and air breathing missiles.

  18. TEMPERATURE-HYDROSTATIC PRESSURE STUDIES ON PARTIALLY PURIFIED INORGANIC PYROPHOSPHATASE ACTIVITY.

    PubMed

    MORITA, R Y; MATHEMEIER, P F

    1964-12-01

    Morita, Richard Y. (Oregon State University, Corvallis), and Paul F. Mathemeier. Temperature-hydrostatic pressure studies on partially purified inorganic pyrophosphatase activity. J. Bacteriol. 88:1667-1671. 1964.-Partially purified inorganic pyrophosphatase from Bacillus stearothermophilus demonstrated increased activity at 90 C with hydrostatic pressures of 100 to 1,100 atm. At 90 C, optimal activity was at 700 atm. No enzyme activity could be demonstrated at 100 C at 1 atm; however, at 105 C moderate hydrostatic pressures favored the enzyme reaction, resulting in increased activity. The increased enzyme activity is explained on the basis of pressure counteracting the molecular volume increase which results from elevated temperature. Thermal denaturation studies at 90 C show inorganic pyrophosphatase to be more stable in the presence of cofactor than substrate, and indicate an enyzme-cofactor intermediate in the hydrolysis. PMID:14240955

  19. Solvability of some partial functional integrodifferential equations with finite delay and optimal controls in Banach spaces.

    PubMed

    Ezzinbi, Khalil; Ndambomve, Patrice

    2016-01-01

    In this work, we consider the control system governed by some partial functional integrodifferential equations with finite delay in Banach spaces. We assume that the undelayed part admits a resolvent operator in the sense of Grimmer. Firstly, some suitable conditions are established to guarantee the existence and uniqueness of mild solutions for a broad class of partial functional integrodifferential infinite dimensional control systems. Secondly, it is proved that, under generally mild conditions of cost functional, the associated Lagrange problem has an optimal solution, and that for each optimal solution there is a minimizing sequence of the problem that converges to the optimal solution with respect to the trajectory, the control, and the functional in appropriate topologies. Our results extend and complement many other important results in the literature. Finally, a concrete example of application is given to illustrate the effectiveness of our main results. PMID:27540497

  20. Human activities recognition by head movement using partial recurrent neural network

    NASA Astrophysics Data System (ADS)

    Tan, Henry C. C.; Jia, Kui; De Silva, Liyanage C.

    2003-06-01

    Traditionally, human activities recognition has been achieved mainly by the statistical pattern recognition methods or the Hidden Markov Model (HMM). In this paper, we propose a novel use of the connectionist approach for the recognition of ten simple human activities: walking, sitting down, getting up, squatting down and standing up, in both lateral and frontal views, in an office environment. By means of tracking the head movement of the subjects over consecutive frames from a database of different color image sequences, and incorporating the Elman model of the partial recurrent neural network (RNN) that learns the sequential patterns of relative change of the head location in the images, the proposed system is able to robustly classify all the ten activities performed by unseen subjects from both sexes, of different race and physique, with a recognition rate as high as 92.5%. This demonstrates the potential of employing partial RNN to recognize complex activities in the increasingly popular human-activities-based applications.

  1. Dual Window Pattern Recognition Classifier for Improved Partial-Hand Prosthesis Control

    PubMed Central

    Earley, Eric J.; Hargrove, Levi J.; Kuiken, Todd A.

    2016-01-01

    Although partial-hand amputees largely retain the ability to use their wrist, it is difficult to preserve wrist motion while using a myoelectric partial-hand prosthesis without severely impacting control performance. Electromyogram (EMG) pattern recognition is a well-studied control method; however, EMG from wrist motion can obscure myoelectric finger control signals. Thus, to accommodate wrist motion and to provide high classification accuracy and minimize system latency, we developed a training protocol and a classifier that switches between long and short EMG analysis window lengths. Seventeen non-amputee and two partial-hand amputee subjects participated in a study to determine the effects of including EMG from different arm and hand locations during static and/or dynamic wrist motion in the classifier training data. We evaluated several real-time classification techniques to determine which control scheme yielded the highest performance in virtual real-time tasks using a three-way ANOVA. We found significant interaction between analysis window length and the number of grasps available. Including static and dynamic wrist motion and intrinsic hand muscle EMG with extrinsic muscle EMG significantly reduced pattern recognition classification error by 35%. Classification delay or majority voting techniques significantly improved real-time task completion rates (17%), selection (23%), and completion (11%) times, and selection attempts (15%) for non-amputee subjects, and the dual window classifier significantly reduced the time (8%) and average number of attempts required to complete grasp selections (14%) made in various wrist positions. Amputee subjects demonstrated improved task timeout rates, and made fewer grasp selection attempts, with classification delay or majority voting techniques. Thus, the proposed techniques show promise for improving control of partial-hand prostheses and more effectively restoring function to individuals using these devices. PMID

  2. ISOLATION AND PARTIAL CHARACTERIZATION OF AN ACID PHOSPHATASE ACTIVITY FROM SPIRODELA OLIGORHIZA

    EPA Science Inventory

    An acid phosphatase activity from the aquatic plant Spirodela oligorhiza (duckweed) was isolated and partially characterized. S. oligorhiza was grown in a hydroponic growth medium, harvested, and ground up in liquid nitrogen. The ground plant material was added to a biological ...

  3. Controls Considerations for Turbine Active Clearance Control

    NASA Technical Reports Server (NTRS)

    Melcher, Kevin J.

    2004-01-01

    This presentation discusses active control of turbine tip clearance from a control systems perspective. It is a subset of charts that were presented at the 2003 meeting of the International Society of Air Breathing Engines which was held August 31 through September 5 in Cleveland, Ohio. The associated reference paper is cited at the end of the presentation. The presentation describes active tip clearance control research being conducted by NASA to improve turbine engine systems. The target application for this effort is commercial aircraft engines. However, it is believed that the technologies developed as part of this research will benefit a broad spectrum of current and future turbomachinery. The first part of the presentation discusses the concept of tip clearance, problems associated with it, and the benefits of controlling it. It lays out a framework for implementing tip clearance controls that enables the implementation to progress from purely analytical to hardware-in-the-loop to fully experimental. And it briefly discusses how the technologies developed will be married to the previously described ACC Test Rig for hardware-in-the-loop demonstrations. The final portion of the presentation, describes one of the key technologies in some detail by presenting equations and results for a functional dynamic model of the tip clearance phenomena. As shown, the model exhibits many of the clearance dynamics found in commercial gas turbine engines. However, initial attempts to validate the model identified limitations that are being addressed to make the model more realistic.

  4. Partial purification of a Bacillus licheniformis levansucrase producing levan with antitumor activity.

    PubMed

    Dahech, Imen; Belghith, Karima Srih; Belghith, Hafedh; Mejdoub, Hafedh

    2012-10-01

    The extracellular fructosyltransferase (FTase) of a novel strain of Bacillus licheniformis capable of producing fructooligosaccharides (FOS) and a polysaccharide type levan was obtained and partially purified. The purification was achieved by ammonium sulfate precipitation, DEAE cellulose and gel filtration chromatographies. The enzyme was partially purified as determined by SDS-PAGE, and the specific activity reached was 67.5, representing a purification factor of 177 and yield of 40%. Levan was isolated from the cultures of B. licheniformis. The levan was composed mainly of fructose residues when analyzed by TLC after acid hydrolysis and NMR analysis. In a previous study, the levan produced exhibited a hypoglycemiant activity. The present paper deals with the study of the antitumor and anti-cytotoxic effect of levan produced by B. licheniformis strain. In the in vitro antitumor activity test of levan against some tumor cell lines, relatively the significantly high activity was observed against the HepG(2). PMID:22579870

  5. Exogenous Magnesium Chloride Reduces the Activated Partial Thromboplastin Times of Lupus Anticoagulant-Positive Patients

    PubMed Central

    Tokutake, Takayoshi; Baba, Hisami; Shimada, Yuji; Takeda, Wataru; Sato, Keijiro; Hiroshima, Yuki; Kirihara, Takehiko; Shimizu, Ikuo; Nakazawa, Hideyuki; Kobayashi, Hikaru; Ishida, Fumihiro

    2016-01-01

    The activated partial thromboplastin time (APTT) assay is a basic hemostatic assay based on the time it takes for clots to form in plasma samples after the addition of calcium chloride. It is used to screen for various coagulation disorders. Several previous reports have suggested that magnesium (Mg) might contribute to coagulation reactions by binding to specific coagulation proteins. We investigated the effects of Mg on the APTT. In healthy controls, the APTT was significantly prolonged in proportion to the increase in the concentration of magnesium chloride in the range from 2.1 to 16.7 mmol/L. Among eight samples from patients with various disorders that exhibited prolonged APTT, two samples demonstrated shorter APTT when Mg was added, both of which were from patients that were positive for lupus anticoagulant. When we examined 206 clinical APTT samples, we found that Mg shortened the APTT of two samples. These two samples were also from lupus anticoagulant-positive patients (p-value: <0.003). Our findings regarding the unique effects of exogenous Mg on the APTT of lupus anticoagulant-positive patients might shed light on the role of Mg in APTT assays and lead to the development of a novel screening method for lupus anticoagulant. PMID:27355205

  6. A Proposal of Partial Model Matching Method for Continuous-Time Generalized Minimum Variance Control

    NASA Astrophysics Data System (ADS)

    Tajima, Jyun-Ichi; Doi, Masayoshi; Mori, Yasuchika

    The proposed method can improve the response for the servo type Continuous-time Generalized Minimum Variance Control (CGMVC). The conventional CGMVC, which is tuned due to the controlled input weighting of the cost function, cannot freely adjust the response in the case of the servo type. This study proposes a new servo CGMVC of tuning the output weighting of the cost function. The proposed CGMVC is applied by the Partial Model Matching (PMM) method. The CGMVC with PMM and tuning the output weighting can improve both the response of tracking the reference signal and the load-disturbance rejection.

  7. Reward-Modulated Hebbian Plasticity as Leverage for Partially Embodied Control in Compliant Robotics

    PubMed Central

    Burms, Jeroen; Caluwaerts, Ken; Dambre, Joni

    2015-01-01

    In embodied computation (or morphological computation), part of the complexity of motor control is offloaded to the body dynamics. We demonstrate that a simple Hebbian-like learning rule can be used to train systems with (partial) embodiment, and can be extended outside of the scope of traditional neural networks. To this end, we apply the learning rule to optimize the connection weights of recurrent neural networks with different topologies and for various tasks. We then apply this learning rule to a simulated compliant tensegrity robot by optimizing static feedback controllers that directly exploit the dynamics of the robot body. This leads to partially embodied controllers, i.e., hybrid controllers that naturally integrate the computations that are performed by the robot body into a neural network architecture. Our results demonstrate the universal applicability of reward-modulated Hebbian learning. Furthermore, they demonstrate the robustness of systems trained with the learning rule. This study strengthens our belief that compliant robots should or can be seen as computational units, instead of dumb hardware that needs a complex controller. This link between compliant robotics and neural networks is also the main reason for our search for simple universal learning rules for both neural networks and robotics. PMID:26347645

  8. Reward-Modulated Hebbian Plasticity as Leverage for Partially Embodied Control in Compliant Robotics.

    PubMed

    Burms, Jeroen; Caluwaerts, Ken; Dambre, Joni

    2015-01-01

    In embodied computation (or morphological computation), part of the complexity of motor control is offloaded to the body dynamics. We demonstrate that a simple Hebbian-like learning rule can be used to train systems with (partial) embodiment, and can be extended outside of the scope of traditional neural networks. To this end, we apply the learning rule to optimize the connection weights of recurrent neural networks with different topologies and for various tasks. We then apply this learning rule to a simulated compliant tensegrity robot by optimizing static feedback controllers that directly exploit the dynamics of the robot body. This leads to partially embodied controllers, i.e., hybrid controllers that naturally integrate the computations that are performed by the robot body into a neural network architecture. Our results demonstrate the universal applicability of reward-modulated Hebbian learning. Furthermore, they demonstrate the robustness of systems trained with the learning rule. This study strengthens our belief that compliant robots should or can be seen as computational units, instead of dumb hardware that needs a complex controller. This link between compliant robotics and neural networks is also the main reason for our search for simple universal learning rules for both neural networks and robotics. PMID:26347645

  9. Improved Efficiency for Partial Oxidation of Methane by Controlled Copper Deposition on Surface‐Modified ZSM‐5

    PubMed Central

    Sheppard, Thomas; Daly, Helen; Goguet, Alex

    2015-01-01

    Abstract The mono(μ‐oxo) dicopper cores present in the pores of Cu‐ZSM‐5 are active for the partial oxidation of methane to methanol. However, copper on the external surface reduces the ratio of active, selective sites to unselective sites. More efficient catalysts are obtained by controlling the copper deposition during synthesis. Herein, the external exchange sites of ZSM‐5 samples were passivated by bis(trimethylsilyl) trifluoroacetamide (BSTFA) followed by calcination, promoting selective deposition of intraporous copper during aqueous copper ion exchange. At an optimum level of 1–2 wt % SiO2, IR studies showed a 64 % relative reduction in external copper species and temperature‐programmed oxidation analysis showed an associated increase in the formation of methanol compared with unmodified Cu‐ZSM‐5 samples. It is, therefore, reported that the modified zeolites contained a significantly higher proportion of active, selective copper species than their unmodified counterparts with activity for partial methane oxidation to methanol. PMID:26925172

  10. Optical control of antibacterial activity

    NASA Astrophysics Data System (ADS)

    Velema, Willem A.; van der Berg, Jan Pieter; Hansen, Mickel J.; Szymanski, Wiktor; Driessen, Arnold J. M.; Feringa, Ben L.

    2013-11-01

    Bacterial resistance is a major problem in the modern world, stemming in part from the build-up of antibiotics in the environment. Novel molecular approaches that enable an externally triggered increase in antibiotic activity with high spatiotemporal resolution and auto-inactivation are highly desirable. Here we report a responsive, broad-spectrum, antibacterial agent that can be temporally activated with light, whereupon it auto-inactivates on the scale of hours. The use of such a ‘smart’ antibiotic might prevent the build-up of active antimicrobial material in the environment. Reversible optical control over active drug concentration enables us to obtain pharmacodynamic information. Precisely localized control of activity is achieved, allowing the growth of bacteria to be confined to defined patterns, which has potential for the development of treatments that avoid interference with the endogenous microbial population in other parts of the organism.

  11. Steady, subsonic, lifting surface theory for wings with swept, partial span, trailing edge control surfaces

    NASA Technical Reports Server (NTRS)

    Medan, R. T.

    1973-01-01

    A method for computing the lifting pressure distribution on a wing with partial span, swept control surfaces is presented. This method is valid within the framework of linearized, steady, potential flow theory and consists of using conventional lifting surface theory in conjuction with a flap pressure mode. The cause of a numerical instability that can occur during the quadrature of the flap pressure mode is discussed, and an efficient technique to eliminate the instability is derived. This technique is valid for both the flap pressure mode and regular pressure modes and could be used to improve existing lifting surface methods. Examples of the use of the flap pressure mode and comparisons among this method, other theoretical methods, and experiments are given. Discrepancies with experiment are indicated and candidate causes are presented. It is concluded that the method can lead to an efficient and accurate solution of the mathematical problem when a partial span, trailing edge flap is involved.

  12. Demonstration of Active Combustion Control

    NASA Technical Reports Server (NTRS)

    Lovett, Jeffrey A.; Teerlinck, Karen A.; Cohen, Jeffrey M.

    2008-01-01

    The primary objective of this effort was to demonstrate active control of combustion instabilities in a direct-injection gas turbine combustor that accurately simulates engine operating conditions and reproduces an engine-type instability. This report documents the second phase of a two-phase effort. The first phase involved the analysis of an instability observed in a developmental aeroengine and the design of a single-nozzle test rig to replicate that phenomenon. This was successfully completed in 2001 and is documented in the Phase I report. This second phase was directed toward demonstration of active control strategies to mitigate this instability and thereby demonstrate the viability of active control for aircraft engine combustors. This involved development of high-speed actuator technology, testing and analysis of how the actuation system was integrated with the combustion system, control algorithm development, and demonstration testing in the single-nozzle test rig. A 30 percent reduction in the amplitude of the high-frequency (570 Hz) instability was achieved using actuation systems and control algorithms developed within this effort. Even larger reductions were shown with a low-frequency (270 Hz) instability. This represents a unique achievement in the development and practical demonstration of active combustion control systems for gas turbine applications.

  13. Active Flow Control Activities at NASA Langley

    NASA Technical Reports Server (NTRS)

    Anders, Scott G.; Sellers, William L., III; Washburn, Anthony E.

    2004-01-01

    NASA Langley continues to aggressively investigate the potential advantages of active flow control over more traditional aerodynamic techniques. This paper provides an update to a previous paper and describes both the progress in the various research areas and the significant changes in the NASA research programs. The goals of the topics presented are focused on advancing the state of knowledge and understanding of controllable fundamental mechanisms in fluids as well as to address engineering challenges. An organizational view of current research activities at NASA Langley in active flow control as supported by several projects is presented. On-center research as well as NASA Langley funded contracts and grants are discussed at a relatively high level. The products of this research are to be demonstrated either in bench-top experiments, wind-tunnel investigations, or in flight as part of the fundamental NASA R&D program and then transferred to more applied research programs within NASA, DOD, and U.S. industry.

  14. Fractional active disturbance rejection control.

    PubMed

    Li, Dazi; Ding, Pan; Gao, Zhiqiang

    2016-05-01

    A fractional active disturbance rejection control (FADRC) scheme is proposed to improve the performance of commensurate linear fractional order systems (FOS) and the robust analysis shows that the controller is also applicable to incommensurate linear FOS control. In FADRC, the traditional extended states observer (ESO) is generalized to a fractional order extended states observer (FESO) by using the fractional calculus, and the tracking differentiator plus nonlinear state error feedback are replaced by a fractional proportional-derivative controller. To simplify controller tuning, the linear bandwidth-parameterization method has been adopted. The impacts of the observer bandwidth ωo and controller bandwidth ωc on system performance are then analyzed. Finally, the FADRC stability and frequency-domain characteristics for linear single-input single-output FOS are analyzed. Simulation results by FADRC and ADRC on typical FOS are compared to demonstrate the superiority and effectiveness of the proposed scheme. PMID:26928516

  15. Extended Active Disturbance Rejection Controller

    NASA Technical Reports Server (NTRS)

    Gao, Zhiqiang (Inventor); Tian, Gang (Inventor)

    2016-01-01

    Multiple designs, systems, methods and processes for controlling a system or plant using an extended active disturbance rejection control (ADRC) based controller are presented. The extended ADRC controller accepts sensor information from the plant. The sensor information is used in conjunction with an extended state observer in combination with a predictor that estimates and predicts the current state of the plant and a co-joined estimate of the system disturbances and system dynamics. The extended state observer estimates and predictions are used in conjunction with a control law that generates an input to the system based in part on the extended state observer estimates and predictions as well as a desired trajectory for the plant to follow.

  16. Extended Active Disturbance Rejection Controller

    NASA Technical Reports Server (NTRS)

    Gao, Zhiqiang (Inventor); Tian, Gang (Inventor)

    2014-01-01

    Multiple designs, systems, methods and processes for controlling a system or plant using an extended active disturbance rejection control (ADRC) based controller are presented. The extended ADRC controller accepts sensor information from the plant. The sensor information is used in conjunction with an extended state observer in combination with a predictor that estimates and predicts the current state of the plant and a co-joined estimate of the system disturbances and system dynamics. The extended state observer estimates and predictions are used in conjunction with a control law that generates an input to the system based in part on the extended state observer estimates and predictions as well as a desired trajectory for the plant to follow.

  17. Extended active disturbance rejection controller

    NASA Technical Reports Server (NTRS)

    Gao, Zhiqiang (Inventor); Tian, Gang (Inventor)

    2012-01-01

    Multiple designs, systems, methods and processes for controlling a system or plant using an extended active disturbance rejection control (ADRC) based controller are presented. The extended ADRC controller accepts sensor information from the plant. The sensor information is used in conjunction with an extended state observer in combination with a predictor that estimates and predicts the current state of the plant and a co-joined estimate of the system disturbances and system dynamics. The extended state observer estimates and predictions are used in conjunction with a control law that generates an input to the system based in part on the extended state observer estimates and predictions as well as a desired trajectory for the plant to follow.

  18. Parallels between control PDE's (Partial Differential Equations) and systems of ODE's (Ordinary Differential Equations)

    NASA Technical Reports Server (NTRS)

    Hunt, L. R.; Villarreal, Ramiro

    1987-01-01

    System theorists understand that the same mathematical objects which determine controllability for nonlinear control systems of ordinary differential equations (ODEs) also determine hypoellipticity for linear partial differentail equations (PDEs). Moreover, almost any study of ODE systems begins with linear systems. It is remarkable that Hormander's paper on hypoellipticity of second order linear p.d.e.'s starts with equations due to Kolmogorov, which are shown to be analogous to the linear PDEs. Eigenvalue placement by state feedback for a controllable linear system can be paralleled for a Kolmogorov equation if an appropriate type of feedback is introduced. Results concerning transformations of nonlinear systems to linear systems are similar to results for transforming a linear PDE to a Kolmogorov equation.

  19. Crystal form control and particle size control of RG3487, a nicotinic α7 receptor partial agonist.

    PubMed

    Kuang, Shanming; Zhang, Pingsheng; Dong, Eric Z; Jennings, Geremia; Zhao, Baoshu; Pierce, Michael

    2016-07-11

    This paper describes solid form control and particle size control of RG3487, a nicotinic receptor partial agonist. Four crystal forms were identified by polymorph screen under ∼100 varying conditions. Form A and Form B are anhydrates, while Forms C and D are solvates. Forms A, which is enantiotropically related to Form B, is the more thermodynamically stable form under ambient conditions and the desired form selected for clinical development. The crystal form control of Form A was achieved by crystallization solvent selection which consistently produced the desired form. Several process parameters impacting particle size of Form A in the final crystallization step were identified and investigated through both online and offline particle size measurement. The investigation results were utilized to control crystallization processes which successfully produced Form A with different particle size in 500g scale. PMID:27167333

  20. Changes in the nuclear protein kinase activities in the regenerating liver of partially irradiated rat

    SciTech Connect

    Asami, K.; Kobayashi, H.; Fujiwara, A.; Yasumasu, I. )

    1989-09-01

    X rays (4.8 Gy) inhibit both DNA synthesis and phosphorylation of histone H1 in the regenerating liver of the rat. To determine the cause of the inhibition of histone H1 phosphorylation, changes in the nuclear protein kinase activities during the prereplicative phase of regeneration were measured. The cAMP-dependent protein kinase activity was low during regeneration, and the changes in the activity were not statistically significant. The cAMP-independent protein kinase activity increased at 15 h, decreased at 18 h, and increased again at 24 h after partial hepatectomy. X irradiation prior to partial hepatectomy did not inhibit the increase at 15 h, but it did inhibit the increase at 24 h. The activity was not inhibited by isoquinolinesulfonamide inhibitors such as H-7, and it was activated by a commercial preparation of an inhibitor protein of the cAMP-dependent kinase. It was also inhibited by quercetin. The possibility that the radiation-sensitive nuclear protein kinase is a nuclear cAMP-independent protein kinase specific for histone H1 is considered.

  1. Dual control active superconductive devices

    DOEpatents

    Martens, Jon S.; Beyer, James B.; Nordman, James E.; Hohenwarter, Gert K. G.

    1993-07-20

    A superconducting active device has dual control inputs and is constructed such that the output of the device is effectively a linear mix of the two input signals. The device is formed of a film of superconducting material on a substrate and has two main conduction channels, each of which includes a weak link region. A first control line extends adjacent to the weak link region in the first channel and a second control line extends adjacent to the weak link region in the second channel. The current flowing from the first channel flows through an internal control line which is also adjacent to the weak link region of the second channel. The weak link regions comprise small links of superconductor, separated by voids, through which the current flows in each channel. Current passed through the control lines causes magnetic flux vortices which propagate across the weak link regions and control the resistance of these regions. The output of the device taken across the input to the main channels and the output of the second main channel and the internal control line will constitute essentially a linear mix of the two input signals imposed on the two control lines. The device is especially suited to microwave applications since it has very low input capacitance, and is well suited to being formed of high temperature superconducting materials since all of the structures may be formed coplanar with one another on a substrate.

  2. Partially Oxidized Sub-10 nm MnO Nanocrystals with High Activity for Water Oxidation Catalysis

    PubMed Central

    Jin, Kyoungsuk; Chu, Arim; Park, Jimin; Jeong, Donghyuk; Jerng, Sung Eun; Sim, Uk; Jeong, Hui-Yun; Lee, Chan Woo; Park, Yong-Sun; Yang, Ki Dong; Kumar Pradhan, Gajendra; Kim, Donghun; Sung, Nark-Eon; Hee Kim, Sun; Nam, Ki Tae

    2015-01-01

    The oxygen evolution reaction (OER) is considered a major bottleneck in the overall water electrolysis process. In this work, highly active manganese oxide nano-catalysts were synthesized via hot injection. Facile surface treatment generated Mn(III) species on monodisperse 10 nm MnO nanocrystals (NCs). Size dependency of MnO NCs on OER activity was also investigated. Surprisingly, the partially oxidized MnO NCs only required 530 mV @ 5 mA cm−2 under near neutral conditions. PMID:25998696

  3. Partially Oxidized Sub-10 nm MnO Nanocrystals with High Activity for Water Oxidation Catalysis

    NASA Astrophysics Data System (ADS)

    Jin, Kyoungsuk; Chu, Arim; Park, Jimin; Jeong, Donghyuk; Jerng, Sung Eun; Sim, Uk; Jeong, Hui-Yun; Lee, Chan Woo; Park, Yong-Sun; Yang, Ki Dong; Kumar Pradhan, Gajendra; Kim, Donghun; Sung, Nark-Eon; Hee Kim, Sun; Nam, Ki Tae

    2015-05-01

    The oxygen evolution reaction (OER) is considered a major bottleneck in the overall water electrolysis process. In this work, highly active manganese oxide nano-catalysts were synthesized via hot injection. Facile surface treatment generated Mn(III) species on monodisperse 10 nm MnO nanocrystals (NCs). Size dependency of MnO NCs on OER activity was also investigated. Surprisingly, the partially oxidized MnO NCs only required 530 mV @ 5 mA cm-2 under near neutral conditions.

  4. Active Interior Noise Control Studies

    NASA Technical Reports Server (NTRS)

    Park, J.; Veeramani, S.; Sampath, A.; Balachandran, B.; Wereley, N.

    1996-01-01

    Analytical and experimental investigations into the control of noise in the interior of a three-dimensional enclosure with a flexible boundary are presented. The rigid boundaries are constructed from acrylic material, and in the different cases considered the flexible boundary is constructed from either aluminum or composite material. Noise generated by an external speaker is transmitted into the enclosure through the flexible boundary and active control is realized by using Lead Zirconate Titanate (PZT) piezoelectric actuators bonded to the flexible boundary. Condenser microphones are used for noise measurements inside and outside the enclosure. Minimization schemes for global and local noise control in the presence of a harmonic disturbance are developed and discussed. In the experiments, analog feedforward control is implemented by using the harmonic disturbance as a reference signal.

  5. Adaptive feedback active noise control

    NASA Astrophysics Data System (ADS)

    Kuo, Sen M.; Vijayan, Dipa

    Feedforward active noise control (ANC) systems use a reference sensor that senses a reference input to the controller. This signal is assumed to be unaffected by the secondary source and is a good measure of the undesired noise to be cancelled by the system. The reference sensor may be acoustic (e.g., microphone) or non-acoustic (e.g., tachometer, optical transducer). An obvious problem when using acoustic sensors is that the reference signal may be corrupted by the canceling signal generated by the secondary source. This problem is known as acoustic feedback. One way of avoiding this is by using a feedback active noise control (FANC) system which dispenses with the reference sensor. The FANC technique originally proposed by Olson and May employs a high gain negative feedback amplifier. This system suffered from the drawback that the error microphone had to be placed very close to the loudspeaker. The operation of the system was restricted to low frequency range and suffered from instability due to the possibility of positive feedback. Feedback systems employing adaptive filtering techniques for active noise control were developed. This paper presents the FANC system modeled as an adaptive prediction scheme.

  6. Drosophila ATM and ATR checkpoint kinases control partially redundant pathways for telomere maintenance

    PubMed Central

    Bi, Xiaolin; Srikanta, Deepa; Fanti, Laura; Pimpinelli, Sergio; Badugu, RamaKrishna; Kellum, Rebecca; Rong, Yikang S.

    2005-01-01

    In higher eukaryotes, the ataxia telangiectasia mutated (ATM) and ATM and Rad3-related (ATR) checkpoint kinases play distinct, but partially overlapping, roles in DNA damage response. Yet their interrelated function has not been defined for telomere maintenance. We discover in Drosophila that the two proteins control partially redundant pathways for telomere protection: the loss of ATM leads to the fusion of some telomeres, whereas the loss of both ATM and ATR renders all telomeres susceptible to fusion. The ATM-controlled pathway includes the Mre11 and Nijmegen breakage syndrome complex but not the Chk2 kinase, whereas the ATR-regulated pathway includes its partner ATR-interacting protein but not the Chk1 kinase. This finding suggests that ATM and ATR regulate different molecular events at the telomeres compared with the sites of DNA damage. This compensatory relationship between ATM and ATR is remarkably similar to that observed in yeast despite the fact that the biochemistry of telomere elongation is completely different in the two model systems. We provide evidence suggesting that both the loading of telomere capping proteins and normal telomeric silencing requires ATM and ATR in Drosophila and propose that ATM and ATR protect telomere integrity by safeguarding chromatin architecture that favors the loading of telomere-elongating, capping, and silencing proteins. PMID:16203987

  7. Environmental control and life support - Partially closed system will save big money

    NASA Technical Reports Server (NTRS)

    Guy, W. W.

    1983-01-01

    Although the NASA space station has not yet been completely defined, realistic estimates may be made of the environmental control and life support system requirements entailed by a crew of eight, a resupply interval of 90 days, an initial launch which includes expendables for the first resupply interval, 7.86 lb/day of water per person, etc. An appraisal of these requirements is presented which strongly suggests the utility of a partially closed life support system. Such a scheme would give the crew high quality water to drink, and recycle nonpotable water from hand washing, bathing, clothes and dish washing, and urinal flushing. The excess recovery process water is electrolyzed to provide metabolic and leakage oxygen. The crew would drink electrolysis water and atmospheric humidity control moisture-derived water.

  8. INFLUENCE OF SUBSTRATE-COFACTOR RATIOS ON PARTIALLY PURIFIED INORGANIC PYROPHOSPHATASE ACTIVITY AT ELEVATED TEMPERATURES.

    PubMed

    MATHEMEIER, P F; MORITA, R Y

    1964-12-01

    Mathemeier, Paul F. (Oregon State University, Corvallis), and Richard Y. Morita. Influence of substrate-cofactor ratios on partially purified inorganic pyrophosphatase activity at elevated temperatures. J. Bacteriol. 88:1661-1666. 1964.-Inorganic pyrophosphatase of Bacillus stearothermophilus was studied for optimal substrate-cofactor ratios at 60 to 100 C. Mg(++) was the primary cofactor, and Co(++) resulted in 50% enzyme activity at 60 C. The pH optima differed for the Mg(++) activated and Co(++) activated pyrophosphatase. At 80 C and above, Co(++) replaced Mg(++) as the optimal cofactor in the enzyme reaction. The optimal ratio of pyrophosphate to Mg(++) varied from 2 to 0.25, dependent on enzyme concentration. The optimal pyrophosphate-cobalt ratio was constant at 1.0. The enzyme catalyzed appreciable pyrophosphate hydrolysis at 95 C. PMID:14240954

  9. Novel Active Combustion Control Valve

    NASA Technical Reports Server (NTRS)

    Caspermeyer, Matt

    2014-01-01

    This project presents an innovative solution for active combustion control. Relative to the state of the art, this concept provides frequency modulation (greater than 1,000 Hz) in combination with high-amplitude modulation (in excess of 30 percent flow) and can be adapted to a large range of fuel injector sizes. Existing valves often have low flow modulation strength. To achieve higher flow modulation requires excessively large valves or too much electrical power to be practical. This active combustion control valve (ACCV) has high-frequency and -amplitude modulation, consumes low electrical power, is closely coupled with the fuel injector for modulation strength, and is practical in size and weight. By mitigating combustion instabilities at higher frequencies than have been previously achieved (approximately 1,000 Hz), this new technology enables gas turbines to run at operating points that produce lower emissions and higher performance.

  10. Clinical results of renal artery embolization to control postoperative hemorrhage after partial nephrectomy

    PubMed Central

    Jeon, Chang Ho; Yoon, Chang Jin; Byun, Seok-Soo; Lee, Sang Eun

    2016-01-01

    Background With the wider application of nephron-sparing surgery, there has been an increase in the occurrence of postoperative hemorrhage. However, despite such an increase, there are only a limited number of reports regarding renal artery embolization (RAE) for the management of postoperative bleeding after nephron-sparing surgery, especially after robot-assisted laparoscopic partial nephrectomy (RALPN). Purpose To evaluate the safety and clinical efficacy of transcatheter RAE for postoperative hemorrhage after open partial nephrectomy (OPN) and RALPN. Material and Methods A total of 29 patients (17 men, 12 women; age range, 31–70 years) who were referred to our hospital for postoperative hemorrhage after partial nephrectomy, between December 2003 and December 2014, were selected. We retrospectively reviewed patients’ clinical data, angiographic findings, embolization details, and clinical outcomes. Results Embolization was performed in patients who underwent OPN (25/29) and RALPN (4/29). The angiographic findings were as follows: renal artery pseudoaneurysm (n = 18), contrast extravasation (n = 8), and arteriovenous fistula (n = 3). Fiber-coated microcoil and n-butyl-2-cyanoacrylate (NBCA) was administered to the targeted bleeding renal arteries in 12 and 11 patients, respectively. In six patients, fiber-coated microcoil and NBCA were used concurrently. Technical and clinical successes were achieved in all patients (100%). Bleeding cessation was achieved in all patients, and no further relevant surgeries or interventions were required for hemorrhage control. There were no episodes of hemorrhagic recurrence during the follow-up period (median, 20 days; range, 7–108 days). Conclusion Angiography and RAE identified the origin of bleeding and could successfully preserve the residual renal function. PMID:27570638

  11. Nitrogenase Activity Is Affected by Reduced Partial Pressures of N2 and NO3- 1.

    PubMed Central

    Blumenthal, J. M.; Russelle, M. P.; Vance, C. P.

    1997-01-01

    Optimal use of legumes in cropping systems requires a thorough understanding of the interaction between inorganic N nutrition and symbiotic N2 fixation. Our objective was to test the hypothesis that increased NO3- uptake by alfalfa (Medicago sativa L.) would compensate for lower N2 fixation caused by low partial pressure of N2. Root systems of hydroponically grown alfalfa at 2 mg L-1 NO3--N were exposed to (a) 80% N2, (b) 7% N2, (c) 2% N2, or (d) 0% N2. Exposure to reduced partial pressures of N2 reduced total nitrogenase activity (TNA, measured as H2 production in 20% O2 and 80% Ar) by 40% within less than 30 min, followed by a recovery period over the next 30 min to initial activity. Five hours after treatments began, the TNA of plants exposed to 7 and 2% N2 was substantially higher than pretreatment activities, whereas the TNA of plants exposed either to 0 or 80% N2 did not differ from pretreatment values. The decline in TNA due to NO3- exposure over 4 d was not affected by reduced partial pressure of N2. During the 1st h the proportion of electrons used for the reduction of N2 fell from 0.52 to 0.23 for plants exposed to 7% N2, and to 0.09 for plants exposed to 2% N2, and remained unchanged for the rest of the experiment. Although the hypothesis that alfalfa compensated with increased NO3- uptake for lower N2 fixation was not validated by our results, we unexpectedly demonstrated that the decline in TNA upon exposure to NO3- was independent of the N2-fixing efficiency (i.e. the amount of N2 reduced by nitrogenase) of the symbiosis. PMID:12223779

  12. Uveal Melanoma Cell Growth Is Inhibited by Aminoimidazole Carboxamide Ribonucleotide (AICAR) Partially Through Activation of AMP-Dependent Kinase

    PubMed Central

    Al-Moujahed, Ahmad; Nicolaou, Fotini; Brodowska, Katarzyna; Papakostas, Thanos D.; Marmalidou, Anna; Ksander, Bruce R.; Miller, Joan W.; Gragoudas, Evangelos; Vavvas, Demetrios G.

    2014-01-01

    Purpose. To evaluate the effects and mechanism of aminoimidazole carboxamide ribonucleotide (AICAR), an AMP-dependent kinase (AMPK) activator, on the growth of uveal melanoma cell lines. Methods. Four different cell lines were treated with AICAR (1–4 mM). Cell growth was assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium (MTT) assay. Cell cycle analysis was conducted by flow cytometry; additionally, expression of cell-cycle control proteins, cell growth transcription factors, and downstream effectors of AMPK were determined by RT-PCR and Western blot. Results. Aminoimidazole carboxamide ribonucleotide inhibited cell growth, induced S-phase arrest, and led to AMPK activation. Aminoimidazole carboxamide ribonucleotide treatment was associated with inhibition of eukaryotic translation initiation factor 4E-BP1 phosphorylation, a marker of mammalian target of rapamycin (mTOR) pathway activity. Aminoimidazole carboxamide ribonucleotide treatment was also associated with downregulation of cyclins A and D, but had minimal effects on the phosphorylation of ribosomal protein S6 or levels of the macroautophagy marker LC3B. The effects of AICAR were abolished by treatment with dipyridamole, an adenosine transporter inhibitor that blocks the entry of AICAR into cells. Treatment with adenosine kinase inhibitor 5-iodotubericidin, which inhibits the conversion of AICAR to its 5′-phosphorylated ribotide 5-aminoimidazole-4-carboxamide-1-D-ribofuranosyl-5′-monophosphate (ZMP; the direct activator of AMPK), reversed most of the growth-inhibitory effects, indicating that some of AICAR's antiproliferative effects are mediated at least partially through AMPK activation. Conclusions. Aminoimidazole carboxamide ribonucleotide inhibited uveal melanoma cell proliferation partially through activation of the AMPK pathway and downregulation of cyclins A1 and D1. PMID:24781943

  13. Improving forecast skill by assimilation of quality-controlled AIRS temperature retrievals under partially cloudy conditions

    NASA Astrophysics Data System (ADS)

    Reale, O.; Susskind, J.; Rosenberg, R.; Brin, E.; Liu, E.; Riishojgaard, L. P.; Terry, J.; Jusem, J. C.

    2008-04-01

    The National Aeronautics and Space Administration (NASA) Atmospheric Infrared Sounder (AIRS) on board the Aqua satellite is now recognized as an important contributor towards the improvement of weather forecasts. At this time only a small fraction of the total data produced by AIRS is being used by operational weather systems. In fact, in addition to effects of thinning and quality control, the only AIRS data assimilated are radiance observations of channels unaffected by clouds. Observations in mid-lower tropospheric sounding AIRS channels are assimilated primarily under completely clear-sky conditions, thus imposing a very severe limitation on the horizontal distribution of the AIRS-derived information. In this work it is shown that the ability to derive accurate temperature profiles from AIRS observations in partially cloud-contaminated areas can be utilized to further improve the impact of AIRS observations in a global model and forecasting system. The analyses produced by assimilating AIRS temperature profiles obtained under partial cloud cover result in a substantially colder representation of the northern hemisphere lower midtroposphere at higher latitudes. This temperature difference has a strong impact, through hydrostatic adjustment, in the midtropospheric geopotential heights, which causes a different representation of the polar vortex especially over northeastern Siberia and Alaska. The AIRS-induced anomaly propagates through the model's dynamics producing improved 5-day forecasts.

  14. Improving Forecast Skill by Assimilation of Quality-controlled AIRS Temperature Retrievals under Partially Cloudy Conditions

    NASA Technical Reports Server (NTRS)

    Reale, O.; Susskind, J.; Rosenberg, R.; Brin, E.; Riishojgaard, L.; Liu, E.; Terry, J.; Jusem, J. C.

    2007-01-01

    The National Aeronautics and Space Administration (NASA) Atmospheric Infrared Sounder (AIRS) on board the Aqua satellite has been long recognized as an important contributor towards the improvement of weather forecasts. At this time only a small fraction of the total data produced by AIRS is being used by operational weather systems. In fact, in addition to effects of thinning and quality control, the only AIRS data assimilated are radiance observations of channels unaffected by clouds. Observations in mid-lower tropospheric sounding AIRS channels are assimilated primarily under completely clear-sky conditions, thus imposing a very severe limitation on the horizontal distribution of the AIRS-derived information. In this work it is shown that the ability to derive accurate temperature profiles from AIRS observations in partially cloud-contaminated areas can be utilized to further improve the impact of AIRS observations in a global model and forecasting system. The analyses produced by assimilating AIRS temperature profiles obtained under partial cloud cover result in a substantially colder representation of the northern hemisphere lower midtroposphere at higher latitudes. This temperature difference has a strong impact, through hydrostatic adjustment, in the midtropospheric geopotential heights, which causes a different representation of the polar vortex especially over northeastern Siberia and Alaska. The AIRS-induced anomaly propagates through the model's dynamics producing improved 5-day forecasts.

  15. Partially Hydrogenated Graphene Materials Exhibit High Electrocatalytic Activities Related to Unintentional Doping with Metallic Impurities.

    PubMed

    Jankovský, Ondřej; Libánská, Alena; Bouša, Daniel; Sedmidubský, David; Matějková, Stanislava; Sofer, Zdeněk

    2016-06-13

    Partially hydrogenated graphene materials, synthesized by the chemical reduction/hydrogenation of two different graphene oxides using zinc powder in acidic environment or aluminum powder in alkaline environment, exhibit high electrocatalytic activities, as well as electrochemical sensing properties. The starting graphene oxides and the resultant hydrogenated graphenes were characterized in detail. Their electrocatalytic activity was examined in the oxygen reduction reaction, whereas sensing properties towards explosives were tested by using picric acid as a redox probe. Findings indicate that the high electrocatalytic performance originates not only from the hydrogenation of graphene, but also from unintentional contamination of graphene with manganese and other metals during synthesis. A careful evaluation of the obtained data and a detailed chemical analysis are necessary to identify the origin of this anomalous electrocatalytic activity. PMID:27167069

  16. Medium Chain Fatty Acids Are Selective Peroxisome Proliferator Activated Receptor (PPAR) γ Activators and Pan-PPAR Partial Agonists

    PubMed Central

    Ayers, Steven D.; Lin, Jean Z.; Cvoro, Aleksandra; Silveira, Rodrigo L.; Martínez, Leandro; Souza, Paulo C. T.; Saidemberg, Daniel; Deng, Tuo; Amato, Angela Angelica; Togashi, Marie; Hsueh, Willa A.; Phillips, Kevin; Palma, Mário Sérgio; Neves, Francisco A. R.; Skaf, Munir S.; Webb, Paul; Polikarpov, Igor

    2012-01-01

    Thiazolidinediones (TZDs) act through peroxisome proliferator activated receptor (PPAR) γ to increase insulin sensitivity in type 2 diabetes (T2DM), but deleterious effects of these ligands mean that selective modulators with improved clinical profiles are needed. We obtained a crystal structure of PPARγ ligand binding domain (LBD) and found that the ligand binding pocket (LBP) is occupied by bacterial medium chain fatty acids (MCFAs). We verified that MCFAs (C8–C10) bind the PPARγ LBD in vitro and showed that they are low-potency partial agonists that display assay-specific actions relative to TZDs; they act as very weak partial agonists in transfections with PPARγ LBD, stronger partial agonists with full length PPARγ and exhibit full blockade of PPARγ phosphorylation by cyclin-dependent kinase 5 (cdk5), linked to reversal of adipose tissue insulin resistance. MCFAs that bind PPARγ also antagonize TZD-dependent adipogenesis in vitro. X-ray structure B-factor analysis and molecular dynamics (MD) simulations suggest that MCFAs weakly stabilize C-terminal activation helix (H) 12 relative to TZDs and this effect is highly dependent on chain length. By contrast, MCFAs preferentially stabilize the H2-H3/β-sheet region and the helix (H) 11-H12 loop relative to TZDs and we propose that MCFA assay-specific actions are linked to their unique binding mode and suggest that it may be possible to identify selective PPARγ modulators with useful clinical profiles among natural products. PMID:22649490

  17. Spatial control over cell attachment by partial solvent entrapment of poly lysine in microfluidic channels

    PubMed Central

    Baman, Nicki K; Schneider, Galen B; Terry, Treniece L; Zaharias, Rebecca; Salem, Aliasger K

    2006-01-01

    We demonstrate spatial control over cell attachment on biodegradable surfaces by flowing cell adhesive poly (D-lysine) (PDL) in a trifluoroethanol (TFE)–water mixture through microfluidic channels placed on a biodegradable poly (lactic acid)–poly (ethylene glycol) (PLA–PEG) substrate. The partial solvent mixture swells the PLA–PEG within the confines of the microfluidic channels allowing PDL to diffuse on to the surface gel layer. When excess water is flowed through the channels substituting the TFE–water mixture, the swollen PLA surface collapses, entrapping PDL polymer. Results using preosteoblast human palatal mesenchymal cells (HEPM) indicate that this new procedure can be used for facile attachment of cells in localized regions. The PEG component of the PLA–PEG copolymer prevents cells from binding to the nonpatterned regions. PMID:17722538

  18. Redundant manipulator techniques for partially decentralized path planning and control of a platoon of autonomous vehicles.

    PubMed

    Stilwell, Daniel J; Bishop, Bradley E; Sylvester, Caleb A

    2005-08-01

    An approach to real-time trajectory generation for platoons of autonomous vehicles is developed from well-known control techniques for redundant robotic manipulators. The partially decentralized structure of this approach permits each vehicle to independently compute its trajectory in real-time using only locally generated information and low-bandwidth feedback generated by a system exogenous to the platoon. Our work is motivated by applications for which communications bandwidth is severely limited, such for platoons of autonomous underwater vehicles. The communication requirements for our trajectory generation approach are independent of the number of vehicles in the platoon, enabling platoons composed of a large number of vehicles to be coordinated despite limited communication bandwidth. PMID:16128465

  19. Continuum Modeling and Control of Large Nonuniform Wireless Networks via Nonlinear Partial Differential Equations

    DOE PAGESBeta

    Zhang, Yang; Chong, Edwin K. P.; Hannig, Jan; Estep, Donald

    2013-01-01

    We inmore » troduce a continuum modeling method to approximate a class of large wireless networks by nonlinear partial differential equations (PDEs). This method is based on the convergence of a sequence of underlying Markov chains of the network indexed by N , the number of nodes in the network. As N goes to infinity, the sequence converges to a continuum limit, which is the solution of a certain nonlinear PDE. We first describe PDE models for networks with uniformly located nodes and then generalize to networks with nonuniformly located, and possibly mobile, nodes. Based on the PDE models, we develop a method to control the transmissions in nonuniform networks so that the continuum limit is invariant under perturbations in node locations. This enables the networks to maintain stable global characteristics in the presence of varying node locations.« less

  20. Studies on Chip Control in Turning by Partially Laser Hardening of Carbon Steel

    NASA Astrophysics Data System (ADS)

    Lin, Yongchuan; Tanaka, Ryutaro; Hosokawa, Akira; Kusano, Takahiko; Ueda, Takashi

    This study deals with the chip control in turning by in-situ laser heat treatment of work material. Medium carbon steel JIS S45C is chosen as workpiece material because the ductile ferrite-pearlite structure of the base material can be relatively easily changed into the hard-brittle martensitic structure by laser heat. For the purpose of practical use, the direct diode laser (DDL) is selected because of its compact size, easiness of handling and high absorbance. Prior to turning process, the continuous-wave laser beam is irradiated on the workpiece surface in a longitudinal direction. This linear heat treatment makes it possible to break chips in turning every one revolution of workpiece at which the material is embrittled. The chip breakability depends mainly on the ratio of heat-treated depth to depth of cut. In spite that the workpiece is partially hardened, abnormal wear or chipping is not observed on the tool face after turning.

  1. Neuronal activity controls transsynaptic geometry.

    PubMed

    Glebov, Oleg O; Cox, Susan; Humphreys, Lawrence; Burrone, Juan

    2016-01-01

    The neuronal synapse is comprised of several distinct zones, including presynaptic vesicle zone (SVZ), active zone (AZ) and postsynaptic density (PSD). While correct relative positioning of these zones is believed to be essential for synaptic function, the mechanisms controlling their mutual localization remain unexplored. Here, we employ high-throughput quantitative confocal imaging, super-resolution and electron microscopy to visualize organization of synaptic subdomains in hippocampal neurons. Silencing of neuronal activity leads to reversible reorganization of the synaptic geometry, resulting in a increased overlap between immunostained AZ and PSD markers; in contrast, the SVZ-AZ spatial coupling is decreased. Bayesian blinking and bleaching (3B) reconstruction reveals that the distance between the AZ-PSD distance is decreased by 30 nm, while electron microscopy shows that the width of the synaptic cleft is decreased by 1.1 nm. Our findings show that multiple aspects of synaptic geometry are dynamically controlled by neuronal activity and suggest mutual repositioning of synaptic components as a potential novel mechanism contributing to the homeostatic forms of synaptic plasticity. PMID:26951792

  2. Neuronal activity controls transsynaptic geometry

    PubMed Central

    Glebov, Oleg O.; Cox, Susan; Humphreys, Lawrence; Burrone, Juan

    2016-01-01

    The neuronal synapse is comprised of several distinct zones, including presynaptic vesicle zone (SVZ), active zone (AZ) and postsynaptic density (PSD). While correct relative positioning of these zones is believed to be essential for synaptic function, the mechanisms controlling their mutual localization remain unexplored. Here, we employ high-throughput quantitative confocal imaging, super-resolution and electron microscopy to visualize organization of synaptic subdomains in hippocampal neurons. Silencing of neuronal activity leads to reversible reorganization of the synaptic geometry, resulting in a increased overlap between immunostained AZ and PSD markers; in contrast, the SVZ-AZ spatial coupling is decreased. Bayesian blinking and bleaching (3B) reconstruction reveals that the distance between the AZ-PSD distance is decreased by 30 nm, while electron microscopy shows that the width of the synaptic cleft is decreased by 1.1 nm. Our findings show that multiple aspects of synaptic geometry are dynamically controlled by neuronal activity and suggest mutual repositioning of synaptic components as a potential novel mechanism contributing to the homeostatic forms of synaptic plasticity. PMID:26951792

  3. Single dose efficacy evaluation of two partial benzodiazepine receptor agonists in photosensitive epilepsy patients: A placebo-controlled pilot study.

    PubMed

    Kasteleijn-Nolst Trenité, Dorothée G A; Groenwold, Rolf H H; Schmidt, Bernd; Löscher, Wolfgang

    2016-05-01

    Benzodiazepines (BZDs) are highly effective to suppress various types of seizures; however, their clinical use is limited due to adverse effects and tolerance and dependence liability. Drugs that act only as partial agonists at the BZD recognition site (initially termed "BZD receptor") of the GABAA receptor chloride ionophore complex or exhibit a GABAA receptor subtype-selectivity are thought to have advantages vs. full agonists such as diazepam and most other clinically used BZDs in that such compounds have less adverse effects and reduced or absent tolerance and dependence liability. One of such compounds, abecarnil, has been clinically evaluated as a novel anxiolytic drug, but, despite its potent preclinical anti-seizure activity, it has not yet been evaluated in patients with epilepsy. In the present proof-of-concept study, we performed a within-subject placebo-controlled, single oral dose study of abecarnil in patients with photosensitive epilepsy. Flumazenil, which is generally considered a BZD receptor antagonist, but has slight partial agonistic properties, was used for comparison. In total, 12 patients were enrolled in this study. Abecarnil, 5 or 10mg, completely abolished the photo-paroxysmal EEG response, while flumazenil, 30, 60 or 100mg, was less effective. The anti-epileptic effect of abecarnil was significantly different from both placebo and flumazenil. Sedative adverse effects were observed after abecarnil but not flumazenil. The study substantiates previous pre-clinical experiments that abecarnil exerts pronounced anti-seizure activity. Epilepsy is often associated with anxiety, so that the anxiolytic activity of abecarnil would be an added advantage when using this compound in epilepsy patients. PMID:26921854

  4. Deformation of partially pumped active mirrors for high average-power diode-pumped solid-state lasers.

    PubMed

    Albach, Daniel; LeTouzé, Geoffroy; Chanteloup, Jean-Christophe

    2011-04-25

    We discuss the deformation of a partially pumped active mirror amplifier as a free standing disk, as implemented in several laser systems. We rely on the Lucia laser project to experimentally evaluate the analytical and numerical deformation models. PMID:21643092

  5. Folding of the anterior cingulate cortex partially explains inhibitory control during childhood: a longitudinal study.

    PubMed

    Borst, G; Cachia, A; Vidal, J; Simon, G; Fischer, C; Pineau, A; Poirel, N; Mangin, J-F; Houdé, O

    2014-07-01

    Difficulties in cognitive control including inhibitory control (IC) are related to the pathophysiology of several psychiatric conditions. In healthy subjects, IC efficiency in childhood is a strong predictor of academic and professional successes later in life. The dorsal anterior cingulate cortex (ACC) is one of the core structures responsible for IC. Although quantitative structural characteristics of the ACC contribute to IC efficiency, the qualitative structural brain characteristics contributing to IC development are less-understood. Using anatomical magnetic resonance imaging, we investigated whether the ACC sulcal pattern at age 5, a stable qualitative characteristic of the brain determined in utero, explains IC at age 9. 18 children performed Stroop tasks at age 5 and age 9. Children with asymmetrical ACC sulcal patterns (n=7) had better IC efficiency at age 5 and age 9 than children with symmetrical ACC sulcal patterns (n=11). The ACC sulcal patterns appear to affect specifically IC efficiency given that the ACC sulcal patterns had no effect on verbal working memory. Our study provides the first evidence that the ACC sulcal pattern - a qualitative structural characteristic of the brain not affected by maturation and learning after birth - partially explains IC efficiency during childhood. PMID:24642370

  6. Cerebral blood flow during paroxysmal EEG activation induced by sleep in patients with complex partial seizures

    SciTech Connect

    Gozukirmizi, E.; Meyer, J.S.; Okabe, T.; Amano, T.; Mortel, K.; Karacan, I.

    1982-01-01

    Cerebral blood flow (CBF) measurements were combined with sleep polysomnography in nine patients with complex partial seizures. Two methods were used: the 133Xe method for measuring regional (rCBF) and the stable xenon CT method for local (LCBF). Compared to nonepileptic subjects, who show diffuse CBF decreases during stages I-II, non-REM sleep onset, patients with complex partial seizures show statistically significant increases in CBF which are maximal in regions where the EEG focus is localized and are predominantly seen in one temporal region but are also propagated to other cerebral areas. Both CBF methods gave comparable results, but greater statistical significance was achieved by stable xenon CT methodology. CBF increases are more diffuse than predicted by EEG paroxysmal activity recorded from scalp electrodes. An advantage of the 133Xe inhalation method was achievement of reliable data despite movement of the head. This was attributed to the use of a helmet which maintained the probes approximated to the scalp. Disadvantages were poor resolution (7 cm3) and two-dimensional information. The advantage of stable xenon CT method is excellent resolution (80 mm3) in three dimensions, but a disadvantage is that movement of the head in patients with seizure disorders may limit satisfactory measurements.

  7. Cerebral blood flow during paroxysmal EEG activation induced by sleep in patients with complex partial seizures.

    PubMed

    Gozukirmizi, E; Meyer, J S; Okabe, T; Amano, T; Mortel, K; Karacan, I

    1982-01-01

    Cerebral blood flow (CBF) measurements were combined with sleep polysomnography in nine patients with complex partial seizures. Two methods were used: the 133Xe method for measuring regional (rCBF) and the stable xenon CT method for local (LCBF). Compared to nonepileptic subjects, who show diffuse CBF decreases during stages I-II, non-REM sleep onset, patients with complex partial seizures show statistically significant increases in CBF which are maximal in regions where the EEG focus is localized and are predominantly seen in one temporal region but are also propagated to other cerebral areas. Both CBF methods gave comparable results, but greater statistical significance was achieved by stable xenon CT methodology. CBF increases are more diffuse than predicted by EEG paroxysmal activity recorded from scalp electrodes. An advantage of the 133Xe inhalation method was achievement of reliable data despite movement of the head. This was attributed to the use of a helmet which maintained the probes approximated to the scalp. Disadvantages were poor resolution (7 cm3) and two-dimensional information. The advantage of stable xenon CT method is excellent resolution (80 mm3) in three dimensions, but a disadvantage is that movement of the head in patients with seizure disorders may limit satisfactory measurements. PMID:7163722

  8. Responsiveness of G protein-coupled odorant receptors is partially attributed to the activation mechanism

    PubMed Central

    Yu, Yiqun; de March, Claire A.; Ni, Mengjue J.; Adipietro, Kaylin A.; Golebiowski, Jérôme; Matsunami, Hiroaki; Ma, Minghong

    2015-01-01

    Mammals detect and discriminate numerous odors via a large family of G protein-coupled odorant receptors (ORs). However, little is known about the molecular and structural basis underlying OR response properties. Using site-directed mutagenesis and computational modeling, we studied ORs sharing high sequence homology but with different response properties. When tested in heterologous cells by diverse odorants, MOR256-3 responded broadly to many odorants, whereas MOR256-8 responded weakly to a few odorants. Out of 36 mutant MOR256-3 ORs, the majority altered the responses to different odorants in a similar manner and the overall response of an OR was positively correlated with its basal activity, an indication of ligand-independent receptor activation. Strikingly, a single mutation in MOR256-8 was sufficient to confer both high basal activity and broad responsiveness to this receptor. These results suggest that broad responsiveness of an OR is at least partially attributed to its activation likelihood. PMID:26627247

  9. Active control technology and the use of multiple control surfaces

    NASA Technical Reports Server (NTRS)

    Hart, J. E.

    1976-01-01

    Needed criteria for active control technology applications in commercial transports are lacking. Criteria for redundancy requirements, believed to be consistent with certification philosophy, are postulated to afford a discussion of the relative value of multiple control surfaces. The control power and frequency bandpass requirements of various active control technology applications are shown to be such that multiple control surfaces offer advantages in minimizing the hydraulic or auxiliary power for the control surface actuators.

  10. Active Spacecraft Potential Control Investigation

    NASA Astrophysics Data System (ADS)

    Torkar, K.; Nakamura, R.; Tajmar, M.; Scharlemann, C.; Jeszenszky, H.; Laky, G.; Fremuth, G.; Escoubet, C. P.; Svenes, K.

    2016-03-01

    In tenuous plasma the floating potential of sunlit spacecraft reaches tens of volts, positive. The corresponding field disturbs measurements of the ambient plasma by electron and ion sensors and can reduce micro-channel plate lifetime in electron detectors owing to large fluxes of attracted photoelectrons. Also the accuracy of electric field measurements may suffer from a high spacecraft potential. The Active Spacecraft Potential Control (ASPOC) neutralizes the spacecraft potential by releasing positive charge produced by indium ion emitters. The method has been successfully applied on other spacecraft such as Cluster and Double Star. Two ASPOC units are present on each spacecraft. Each unit contains four ion emitters, whereby one emitter per instrument is operated at a time. ASPOC for the Magnetospheric Multiscale (MMS) mission includes new developments in the design of the emitters and the electronics. New features include the use of capillaries instead of needles, new materials for the emitters and their internal thermal insulators, an extended voltage and current range of the electronics, both for ion emission and heating purposes, and a more capable control software. This enables lower spacecraft potentials, higher reliability, and a more uniform potential structure in the spacecraft's sheath compared to previous missions. Results from on-ground testing demonstrate compliance with requirements. Model calculations confirm the findings from previous applications that the plasma measurements will not be affected by the beam's space charge. Finally, the various operating modes to adapt to changing boundary conditions are described along with the main data products.

  11. Reconstitution of glucotoxic HIT-T15 cells with somatostatin transcription factor-1 partially restores insulin promoter activity.

    PubMed

    Harmon, J S; Tanaka, Y; Olson, L K; Robertson, R P

    1998-06-01

    We have reported that chronic culture of HIT-T15 cells in medium containing supraphysiologic glucose concentrations (11.1 mmol/l) causes a decrease in insulin mRNA levels, insulin content, and insulin release. Furthermore, decreases in insulin gene transcription and binding activity of two essential beta-cell transcription factors, somatostatin transcription factor-1 (STF-1; also known as GSTF, IDX-1, IPF-1, PDX-1, and GSF) and RIPE-3b1 activator, are associated with this glucotoxic effect. In this study, we observed that the loss of RIPE-3b1 occurs much earlier (79% decrease at passage [p]81) than the loss of STF-1 (65% decrease at p104), with abolishment of both factors by p122. Since the STF-1, but not the RIPE-3b1 activator, gene has been cloned, we examined its restorative effects on insulin gene promoter activity after reconstitution with STF-1 cDNA. Basal insulin promoter activities normalized to early (p71-74) passage cells (1.000 +/- 0.069) were 0.4066 +/- 0.093 and 0.142 +/- 0.034 for intermediate (p102-106) and late (p118-122) passage cells, respectively. Early, intermediate, and late passage cells, all chronically cultured in medium containing 11.1 mmol/l glucose, were transfected with STF-1 alone or cotransfected with E2-5, an E-box factor known to be synergistically associated with STF-1. Compared with basal levels, we observed a trend toward an increase in insulin promoter activity in intermediate passage cells with STF-1 transfection (1.43-fold) that became a significant increase when E2-5 was cotransfected (1.78-fold). In late passage cells, transfection of STF-1 alone significantly stimulated a 2.2-fold increase in the insulin promoter activity. Cotransfection of STF-1 and E2-5 in late passage cells stimulated insulin promoter activity 2.8-fold, which was 40% of the activity observed in early passage cells. Control studies in glucotoxic betaTC-6 cells deficient in RIPE-3b1 activator but not STF-1 did not demonstrate an increase in insulin promoter

  12. Thermal expansion measurement of (U,Pu)O2-x in oxygen partial pressure-controlled atmosphere

    NASA Astrophysics Data System (ADS)

    Kato, Masato; Ikusawa, Yoshihisa; Sunaoshi, Takeo; Nelson, Andrew T.; McClellan, Kenneth J.

    2016-02-01

    Thermal expansion of U0.7Pu0.3O2-x (x = 0, 0.01, 0.02, 0.03) and U0.52Pu0.48O2.00 was investigated by a unique dilatometry which measured in an oxygen partial pressure-controlled atmosphere. The oxygen partial pressure was controlled to hold a constant oxygen-to-metal ratio in the (U,Pu)O2-x during the measurement. Thermal expansion slightly increased with the decrease in oxygen-to-metal ratio. We proposed a relationship to describe thermal expansion as a function of temperature, O/M and Pu content.

  13. Crystalline structure of ceria particles controlled by the oxygen partial pressure and STI CMP performances.

    PubMed

    Kim, Ye-Hwan; Kim, Sang-Kyun; Kim, Namsoo; Park, Jea-Gun; Paik, Ungyu

    2008-09-01

    The effect of the crystalline structures of nano-sized ceria particles on shallow trench isolation (STI) chemical mechanical planarization (CMP) performance was investigated. The ceria particles were synthesized via a solid-state displacement reaction method, and their crystalline structure was controlled by regulating the oxygen partial pressure at the reaction site on the precursor. The crystalline structures of ceria particles were analyzed by the high-resolution TEM nano-beam diffraction pattern. In a calcination process with a high oxygen concentration, the synthesized ceria particles had a cubic fluorite structure (CeO(2)), because of the decarbonation of the cerium precursor. However, a low oxygen concentration results in a hexagonal phase cerium oxide (Ce(2)O(3)) rather than the cubic phase due to the insufficient oxidation of Ce(3+) to Ce(4+). In the STI CMP evaluation, the ceria slurry prepared with the cubic CeO(2) shows enhanced performances of the oxide-to-nitride removal selectivity. PMID:18562111

  14. Interictal regional cerebral blood flow during non specific activation test in partial epilepsy.

    PubMed Central

    Valmier, J; Touchon, J; Baldy-Moulinier, M

    1989-01-01

    In order to investigate, during activation testing, the interictal cortical cerebral blood flows (rCBF) of epileptic patients suffering from complex partial seizures, 40 epileptic patients (divided into "lesional", this is, with abnormal CT findings, and "non lesional", that is, with normal CT findings) were submitted to rCBF measurements with the 133 xenon intravenous technique, at rest and during intermittent light stimulation (ILS). The findings compared with normal volunteers seem to demonstrate that, during ILS, (1) in non lesional patients, the suspected epileptic focus shows a significant rCBF increase (2) in lesional patients, the significant rCBF increases were not in the region of the suspected epileptic focus but in adjacent or in contralateral ones. It was concluded that activation interictal rCBF measurements are more useful than resting ones for the determination of epileptic foci when CT findings are normal and that the nature of the epileptic focus influences markedly the interhemispheric activation pattern. PMID:2926422

  15. Total or Partial Knee Arthroplasty Trial - TOPKAT: study protocol for a randomised controlled trial

    PubMed Central

    2013-01-01

    Background In the majority of patients with osteoarthritis of the knee the disease originates in the medial compartment. There are two fundamentally different approaches to knee replacement for patients with unicompartmental disease: some surgeons feel that it is always best to replace both the knee compartments with a total knee replacement (TKR); whereas others feel it is best to replace just the damaged component of the knee using a partial or unicompartment replacement (UKR). Both interventions are established and well-documented procedures. Little evidence exists to prove the clinical and cost-effectiveness of either management option. This provides an explanation for the high variation in treatment of choice by individual surgeons for the same knee pathology. The aim of the TOPKAT study will be to assess the clinical and cost effectiveness of TKRs compared to UKRs in patients with medial compartment osteoarthritis. Methods/Design The design of the study is a single layer multicentre superiority type randomised controlled trial of unilateral knee replacement patients. Blinding will not be possible as the surgical scars for each procedure differ. We aim to recruit 500 patients from approximately 28 secondary care orthopaedic units from across the UK including district general and teaching hospitals. Participants will be randomised to either UKR or TKR. Randomisation will occur using a web-based randomisation system. The study is pragmatic in terms of implant selection for the knee replacement operation. Participants will be followed up for 5 years. The primary outcome is the Oxford Knee Score, which will be collected via questionnaires at 2 months, 1 year and then annually to 5 years. Secondary outcomes will include cost-effectiveness, patient satisfaction and complications data. Trial registration Current Controlled Trials ISRCTN03013488; ClinicalTrials.gov Identifier: NCT01352247 PMID:24028414

  16. N,O6-partially acetylated chitosan nanoparticles hydrophobically-modified for controlled release of steroids and vitamin E.

    PubMed

    Quiñones, Javier Pérez; Gothelf, Kurt Vesterager; Kjems, Jørgen; Caballero, Ángeles María Heras; Schmidt, Claudia; Covas, Carlos Peniche

    2013-01-01

    Diosgenin, two synthetic analogs of brassinosteroids, testosterone and dl-α-tocopherol were covalently linked to synthetic water-soluble N,O6-partially acetylated chitosan, for their controlled release. Drug linking was confirmed by FTIR spectroscopy and proton NMR. Conjugates were also characterized by differential scanning calorimetry and wide-angle X-ray diffraction. These conjugates formed self-assembled nanoparticles in aqueous solution with particle sizes ranging from 197 to 358 nm and drug contents between 11.8 and 56.4% (w/w). Spherical 30-60 nm nanoparticles were observed by scanning electron microscopy and transmission electron microscopy upon drying. In vitro release studies performed at acid pH indicated a drug release dependence on substitution degree and particle sizes. Almost constant release rates were observed during the first 6-8h. Brassinosteroids-modified nanoparticles showed good agrochemical activity in radish seeds bioassay at 10(-1) to 10(-4) mg mL(-1). Tocopheryl-modified nanoparticles exhibited radical scavenging activity in DPPH test. PMID:23044115

  17. Isotherm-Based Thermodynamic Models for Solute Activities of Organic Acids with Consideration of Partial Dissociation.

    PubMed

    Nandy, Lucy; Ohm, Peter B; Dutcher, Cari S

    2016-06-23

    Organic acids make up a significant fraction of the organic mass in atmospheric aerosol particles. The calculation of gas-liquid-solid equilibrium partitioning of the organic acid is therefore critical for accurate determination of atmospheric aerosol physicochemical properties and processes such as new particle formation and activation to cloud condensation nuclei. Previously, an adsorption isotherm-based statistical thermodynamic model was developed for capturing solute concentration-activity relationships for multicomponent aqueous solutions over the entire concentration range (Dutcher et al. J. Phys. Chem. C/A 2011, 2012, 2013), with model parameters for energies of adsorption successfully related to dipole-dipole electrostatic forces in solute-solvent and solvent-solvent interactions for both electrolytes and organics (Ohm et al. J. Phys. Chem. A 2015). However, careful attention is needed for weakly dissociating semivolatile organic acids. Dicarboxylic acids, such as malonic acid and glutaric acid are treated here as a mixture of nondissociated organic solute (HA) and dissociated solute (H(+) + A(-)). It was found that the apparent dissociation was greater than that predicted by known dissociation constants alone, emphasizing the effect of dissociation on osmotic and activity coefficient predictions. To avoid additional parametrization from the mixture approach, an expression was used to relate the Debye-Hückel hard-core collision diameter to the adjustable solute-solvent intermolecular distance. An improved reference state treatment for electrolyte-organic aqueous mixtures, such as that observed here with partial dissociation, has also been proposed. This work results in predictive correlations for estimation of organic acid and water activities for which there is little or no activity data. PMID:27222917

  18. Active thermal control system evolution

    NASA Technical Reports Server (NTRS)

    Petete, Patricia A.; Ames, Brian E.

    1991-01-01

    The 'restructured' baseline of the Space Station Freedom (SSF) has eliminated many of the growth options for the Active Thermal Control System (ATCS). Modular addition of baseline technology to increase heat rejection will be extremely difficult. The system design and the available real estate no longer accommodate this type of growth. As the station matures during its thirty years of operation, a demand of up to 165 kW of heat rejection can be expected. The baseline configuration will be able to provide 82.5 kW at Eight Manned Crew Capability (EMCC). The growth paths necessary to reach 165 kW have been identified. Doubling the heat rejection capability of SSF will require either the modification of existing radiator wings or the attachment of growth structure to the baseline truss for growth radiator wing placement. Radiator performance can be improved by enlarging the surface area or by boosting the operating temperature with a heat pump. The optimal solution will require both modifications. The addition of growth structure would permit the addition of a parallel ATCS using baseline technology. This growth system would simplify integration. The feasibility of incorporating these growth options to improve the heat rejection capacity of SSF is under evaluation.

  19. Active control of combustion instability

    SciTech Connect

    Lang, W.; Poinsot, T.; Candel, S.

    1987-12-01

    The principle of 'antisound' is used to construct a method for the suppression of combustion instabilities. This active instability control (AIC) method uses external acoustic excitation by a loudspeaker to suppress the oscillations of a flame. The excitation signal is provided by a microphone located upstream of the flame. This signal is filtered, processed, amplified, and sent to the loudspeaker. The AIC method is validated on a laboratory combustor. It allows the suppression of all unstable modes of the burner for any operating ratio. The influence of the microphone and loudspeaker locations on the performance of the AIC system is described. For a given configuration, domains of stability, i.e., domains where the AIC system parameters provide suppression of the oscillation, are investigated. Measurements of the electric input of the loudspeaker show that the energy consumption of the AIC system is almost negligible and suggest that this method could be used for industrial combustor stabilization. Finally, a simple model describing the effects of the AIC system is developed and its results compared to the experiment.

  20. Identification of BRCA1 missense substitutions that confer partial functional activity: potential moderate risk variants?

    PubMed Central

    Lovelock, Paul K; Spurdle, Amanda B; Mok, Myth TS; Farrugia, Daniel J; Lakhani, Sunil R; Healey, Sue; Arnold, Stephen; Buchanan, Daniel; Investigators, kConFab; Couch, Fergus J; Henderson, Beric R; Goldgar, David E; Tavtigian, Sean V; Chenevix-Trench, Georgia; Brown, Melissa A

    2007-01-01

    Introduction Many of the DNA sequence variants identified in the breast cancer susceptibility gene BRCA1 remain unclassified in terms of their potential pathogenicity. Both multifactorial likelihood analysis and functional approaches have been proposed as a means to elucidate likely clinical significance of such variants, but analysis of the comparative value of these methods for classifying all sequence variants has been limited. Methods We have compared the results from multifactorial likelihood analysis with those from several functional analyses for the four BRCA1 sequence variants A1708E, G1738R, R1699Q, and A1708V. Results Our results show that multifactorial likelihood analysis, which incorporates sequence conservation, co-inheritance, segregation, and tumour immunohistochemical analysis, may improve classification of variants. For A1708E, previously shown to be functionally compromised, analysis of oestrogen receptor, cytokeratin 5/6, and cytokeratin 14 tumour expression data significantly strengthened the prediction of pathogenicity, giving a posterior probability of pathogenicity of 99%. For G1738R, shown to be functionally defective in this study, immunohistochemistry analysis confirmed previous findings of inconsistent 'BRCA1-like' phenotypes for the two tumours studied, and the posterior probability for this variant was 96%. The posterior probabilities of R1699Q and A1708V were 54% and 69%, respectively, only moderately suggestive of increased risk. Interestingly, results from functional analyses suggest that both of these variants have only partial functional activity. R1699Q was defective in foci formation in response to DNA damage and displayed intermediate transcriptional transactivation activity but showed no evidence for centrosome amplification. In contrast, A1708V displayed an intermediate transcriptional transactivation activity and a normal foci formation response in response to DNA damage but induced centrosome amplification. Conclusion

  1. Status and trends in active control technology

    NASA Technical Reports Server (NTRS)

    Rediess, H. A.; Szalai, K. J.

    1975-01-01

    The emergence of highly reliable fly-by-wire flight control systems makes it possible to consider a strong reliance on automatic control systems in the design optimization of future aircraft. This design philosophy has been referred to as the control configured vehicle approach or the application of active control technology. Several studies and flight tests sponsored by the Air Force and NASA have demonstrated the potential benefits of control configured vehicles and active control technology. The present status and trends of active control technology are reviewed and the impact it will have on aircraft designs, design techniques, and the designer is predicted.

  2. Identification of QTL controlling high levels of partial resistance to Fusarium solani f. sp. pisi in pea

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fusarium root rot is a common biotic restraint on pea yields worldwide and genetic resistance is the most feasible method for improving pea production. This study was conducted to discover quantitative trait loci (QTL) controlling genetic partial resistance to Fusarium root rot caused by Fusarium s...

  3. Comparison of Exposure Controls, Item Pool Characteristics, and Population Distributions for CAT Using the Partial Credit Model

    ERIC Educational Resources Information Center

    Lee, HwaYoung; Dodd, Barbara G.

    2012-01-01

    This study investigated item exposure control procedures under various combinations of item pool characteristics and ability distributions in computerized adaptive testing based on the partial credit model. Three variables were manipulated: item pool characteristics (120 items for each of easy, medium, and hard item pools), two ability…

  4. Rational design of orally-active, pyrrolidine-based progesterone receptor partial agonists

    SciTech Connect

    Thompson, Scott K.; Washburn, David G.; Frazee, James S.; Madauss, Kevin P.; Hoang, Tram H.; Lapinski, Leahann; Grygielko, Eugene T.; Glace, Lindsay E.; Trizna, Walter; Williams, Shawn P.; Duraiswami, Chaya; Bray, Jeffrey D.; Laping, Nicholas J.

    2010-09-03

    Using the X-ray crystal structure of an amide-based progesterone receptor (PR) partial agonist bound to the PR ligand binding domain, a novel PR partial agonist class containing a pyrrolidine ring was designed. Members of this class of N-alkylpyrrolidines demonstrate potent and highly selective partial agonism of the progesterone receptor, and one of these analogs was shown to be efficacious upon oral dosing in the OVX rat model of estrogen opposition.

  5. Overview of Langley activities in active controls research

    NASA Technical Reports Server (NTRS)

    Abel, I.; Newsom, J. R.

    1981-01-01

    The application of active controls technology to reduce aeroelastic response of aircraft structures offers a potential for significant payoffs in terms of aerodynamic efficiency and weight savings. The activities of the Langley Research Center (laRC) in advancing active controls technology. Activities are categorized into the development of appropriate analysis tools, control law synthesis methodology, and experimental investigations aimed at verifying both analysis and synthesis methodology.

  6. Chemical control of dissolution-driven convection in partially miscible systems: theoretical classification.

    PubMed

    Loodts, V; Rongy, L; De Wit, A

    2015-11-28

    Dissolution-driven convection occurs in the host phase of a partially miscible system when a buoyantly unstable density stratification develops upon dissolution. Reactions can impact such convection by changing the composition and thus the density of the host phase. Here we study the influence of A + B → C reactions on such convective dissolution when A is the dissolving species and B a reactant initially in solution in the host phase. We perform a linear stability analysis of related reaction-diffusion density profiles to compare the growth rate of the instability in the reactive case to its non reactive counterpart when all species diffuse at the same rate. We classify the stabilizing or destabilizing influence of reactions on the buoyancy-driven convection in a parameter space spanned by the solutal Rayleigh numbers RA,B,C of chemical species A, B, C and by the ratio β of initial concentrations of the reactants. For RA > 0, the non reactive dissolution of A in the host phase is buoyantly unstable. In that case, we show that the reaction is enhancing convection provided C is sufficiently denser than B. Increasing the ratio β of initial reactant concentrations increases the effect of chemistry but does not significantly impact the stabilizing/destabilizing classification. When the non reactive case is buoyantly stable (RA≤ 0), reactions can create in time an unstable density stratification and trigger convection if RC > RB. Our theoretical approach allows classifying previous results in a unifying picture and developing strategies for the chemical control of convective dissolution. PMID:26486608

  7. MIT Middeck Active Control Experiment (MACE): noncollocated payload pointing control

    NASA Astrophysics Data System (ADS)

    MacMartin, Douglas G.; Miller, David W.

    1993-09-01

    The Middeck Active Control Experiment is a space shuttle flight experiment intended to demonstrate high authority active structural control in zero gravity conditions. The prediction of on-orbit closed-loop dynamics is based on analysis and ground testing. The MACE test article is representative of multiple payload platforms, and includes two 2-axis gimballing payloads connected by a flexible bus. The goal of active control is to maintain pointing accuracy of one payload, while the remaining payload is moving independently. Current control results on the ground test article are presented. Multiple input, multiple output controllers are designed based on high order measurement based models. Linear Quadratic Gaussian controllers yield reasonable performance. At high authority, however, these controllers destabilize the actual structure, due to parametric errors in the control design model. A robust control design procedure is required to yield high performance in the presence of these errors.

  8. Evaluation of Prothrombin Time and Activated Partial Thromboplastin Time in Hypertensive Patients Attending a Tertiary Hospital in Calabar, Nigeria

    PubMed Central

    Nnenna Adaeze, Nnamani; Uchenna Emeribe, Anthony; Abdullahi Nasiru, Idris; Babayo, Adamu; Uko, Emmanuel K.

    2014-01-01

    Introduction. Several biomedical findings have established the effects of hypertension on haemostasis and roles of blood coagulation products in the clinical course of hypertension. Methods. This cross-sectional study aimed at determining effects of hypertension on prothrombin time (PT) and activated partial thromboplastin time (APTT) in hypertensive patients in comparison with normotensive subjects attending a tertiary hospital in Calabar. Forty-two (42) hypertensive patients and thirty-nine (39) normotensive control subjects were investigated for PT and APTT using Quick one-stage methods. Results. Systolic blood pressure (SBP) and diastolic blood pressure (DBP) correlated positively with APTT (r = 0.3072, r = 0.4988; P < 0.05) in hypertensive patients. DBP, SBP, PT, and APTT were significantly higher in hypertensive patients when compared to normotensive subjects (P < 0.05). DBP correlated negatively with duration of illness (r = −0.3097; P < 0.05) in hypertensive patients and positively with age of normotensive subjects (r = 0.3523; P < 0.05). Conclusion. The results obtained indicated that measurements of PT and APTT may serve as indices for evaluating hemostatic abnormalities in hypertensive patients and guide for antihypertensive therapy. However, to have better understanding of hemostatic activities in hypertension, it is recommended to conduct D-dimer, platelet factors, and protein assays. PMID:25477963

  9. Estimation of active pharmaceutical ingredients content using locally weighted partial least squares and statistical wavelength selection.

    PubMed

    Kim, Sanghong; Kano, Manabu; Nakagawa, Hiroshi; Hasebe, Shinji

    2011-12-15

    Development of quality estimation models using near infrared spectroscopy (NIRS) and multivariate analysis has been accelerated as a process analytical technology (PAT) tool in the pharmaceutical industry. Although linear regression methods such as partial least squares (PLS) are widely used, they cannot always achieve high estimation accuracy because physical and chemical properties of a measuring object have a complex effect on NIR spectra. In this research, locally weighted PLS (LW-PLS) which utilizes a newly defined similarity between samples is proposed to estimate active pharmaceutical ingredient (API) content in granules for tableting. In addition, a statistical wavelength selection method which quantifies the effect of API content and other factors on NIR spectra is proposed. LW-PLS and the proposed wavelength selection method were applied to real process data provided by Daiichi Sankyo Co., Ltd., and the estimation accuracy was improved by 38.6% in root mean square error of prediction (RMSEP) compared to the conventional PLS using wavelengths selected on the basis of variable importance on the projection (VIP). The results clearly show that the proposed calibration modeling technique is useful for API content estimation and is superior to the conventional one. PMID:22001843

  10. Identification of PPARgamma Partial Agonists of Natural Origin (II): In Silico Prediction in Natural Extracts with Known Antidiabetic Activity

    PubMed Central

    Guasch, Laura; Sala, Esther; Mulero, Miquel; Valls, Cristina; Salvadó, Maria Josepa; Pujadas, Gerard; Garcia-Vallvé, Santiago

    2013-01-01

    Background Natural extracts have played an important role in the prevention and treatment of diseases and are important sources for drug discovery. However, to be effectively used in these processes, natural extracts must be characterized through the identification of their active compounds and their modes of action. Methodology/Principal Findings From an initial set of 29,779 natural products that are annotated with their natural source and using a previously developed virtual screening procedure (carefully validated experimentally), we have predicted as potential peroxisome proliferators-activated receptor gamma (PPARγ) partial agonists 12 molecules from 11 extracts known to have antidiabetic activity. Six of these molecules are similar to molecules with described antidiabetic activity but whose mechanism of action is unknown. Therefore, it is plausible that these 12 molecules could be the bioactive molecules responsible, at least in part, for the antidiabetic activity of the extracts containing them. In addition, we have also identified as potential PPARγ partial agonists 10 molecules from 16 plants with undescribed antidiabetic activity but that are related (i.e., they are from the same genus) to plants with known antidiabetic properties. None of the 22 molecules that we predict as PPARγ partial agonists show chemical similarity with a group of 211 known PPARγ partial agonists obtained from the literature. Conclusions/Significance Our results provide a new hypothesis about the active molecules of natural extracts with antidiabetic properties and their mode of action. We also suggest plants with undescribed antidiabetic activity that may contain PPARγ partial agonists. These plants represent a new source of potential antidiabetic extracts. Consequently, our work opens the door to the discovery of new antidiabetic extracts and molecules that can be of use, for instance, in the design of new antidiabetic drugs or functional foods focused towards the

  11. Investigations on the stability, oscillation, and stress conditions of airplanes with tab control. Second partial report : application of the solutions obtained in the first partial report to tab-controlled airplanes.

    NASA Technical Reports Server (NTRS)

    Filzek, B

    1949-01-01

    The first partial report, FB 2000, contained a discussion of the derivation of the equations of motion and their solutions for a tab-controlled airplane; the results obtained there are now to be applied to the longitudinal motion of tab-controlled airplanes. In view of the abundance of structural factors and aerodynamic parameters, a general discussion of the problems is unfeasible. Thus it is demonstrated on the basis of examples what stability, oscillation, and stress conditions are to be expected for tab-controlled airplanes. (author)

  12. Partial Sleep Restriction Activates Immune Response-Related Gene Expression Pathways: Experimental and Epidemiological Studies in Humans

    PubMed Central

    Rantanen, Ville; Kronholm, Erkki; Surakka, Ida; van Leeuwen, Wessel M. A.; Lehto, Maili; Matikainen, Sampsa; Ripatti, Samuli; Härmä, Mikko; Sallinen, Mikael; Salomaa, Veikko; Jauhiainen, Matti; Alenius, Harri; Paunio, Tiina; Porkka-Heiskanen, Tarja

    2013-01-01

    Epidemiological studies have shown that short or insufficient sleep is associated with increased risk for metabolic diseases and mortality. To elucidate mechanisms behind this connection, we aimed to identify genes and pathways affected by experimentally induced, partial sleep restriction and to verify their connection to insufficient sleep at population level. The experimental design simulated sleep restriction during a working week: sleep of healthy men (N = 9) was restricted to 4 h/night for five nights. The control subjects (N = 4) spent 8 h/night in bed. Leukocyte RNA expression was analyzed at baseline, after sleep restriction, and after recovery using whole genome microarrays complemented with pathway and transcription factor analysis. Expression levels of the ten most up-regulated and ten most down-regulated transcripts were correlated with subjective assessment of insufficient sleep in a population cohort (N = 472). Experimental sleep restriction altered the expression of 117 genes. Eight of the 25 most up-regulated transcripts were related to immune function. Accordingly, fifteen of the 25 most up-regulated Gene Ontology pathways were also related to immune function, including those for B cell activation, interleukin 8 production, and NF-κB signaling (P<0.005). Of the ten most up-regulated genes, expression of STX16 correlated negatively with self-reported insufficient sleep in a population sample, while three other genes showed tendency for positive correlation. Of the ten most down-regulated genes, TBX21 and LGR6 correlated negatively and TGFBR3 positively with insufficient sleep. Partial sleep restriction affects the regulation of signaling pathways related to the immune system. Some of these changes appear to be long-lasting and may at least partly explain how prolonged sleep restriction can contribute to inflammation-associated pathological states, such as cardiometabolic diseases. PMID:24194869

  13. Orbiter active thermal control system description

    NASA Technical Reports Server (NTRS)

    Laubach, G. E.

    1975-01-01

    A brief description of the Orbiter Active Thermal Control System (ATCS) including (1) major functional requirements of heat load, temperature control and heat sink utilization, (2) the overall system arrangement, and (3) detailed description of the elements of the ATCS.

  14. Developing Internal Controls through Activities

    ERIC Educational Resources Information Center

    Barnes, F. Herbert

    2009-01-01

    Life events can include the Tuesday afternoon cooking class with the group worker or the Saturday afternoon football game, but in the sense that Fritz Redl thought of them, these activities are only threads in a fabric of living that includes all the elements of daily life: playing, working, school-based learning, learning through activities,…

  15. Active Compliance And Damping In Telemanipulator Control

    NASA Technical Reports Server (NTRS)

    Kim, Won S.; Bejczy, Antal K.; Hannaford, Blake

    1991-01-01

    Experimental telemanipulator system of force-reflecting-hand-controller type provides for active compliance and damping in remote, robotic manipulator hand. Distributed-computing and -control system for research in various combinations of force-reflecting and active-compliance control regimes. Shared compliance control implemented by low-pass-filtered force/torque feedback. Variable simulated springs and shock absorbers soften collisions and increase dexterity.

  16. The Middeck Active Control Experiment (MACE)

    NASA Technical Reports Server (NTRS)

    Miller, David W.

    1992-01-01

    Viewgraphs on the Middeck Active Control Experiment (MACE) are presented. Topics covered include: program objectives; program features; flight experiment features; current activities; MACE development model lab testing; MACE test article deployed on STS middeck; and development model testing.

  17. The Middeck Active Control Experiment (MACE)

    NASA Astrophysics Data System (ADS)

    Miller, David W.

    Viewgraphs on the Middeck Active Control Experiment (MACE) are presented. Topics covered include: program objectives; program features; flight experiment features; current activities; MACE development model lab testing; MACE test article deployed on STS middeck; and development model testing.

  18. Synteny analysis of loci controlling partial resistance to Aphanomyces euteiches between Pisum sativum and Medicago truncatula

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aphanomyces root rot, due to Aphanomyces euteiches, is one of the most damaging diseases of pea worldwide. Breeding for partial polygenic resistance to Aphanomyces root rot is a major objective for the development of the pea crop in Europe. Our objectives were to study i)- the diversity of resistanc...

  19. Porcine pituitary peptides with opiate-like activity: partial purification and effects in the rat after intraventricular injection.

    PubMed

    Teschemacher, H; Bläsig, J; Kromer, W

    1976-09-01

    A peptide material with opiate-like activity in the guinea-pig ileum was extracted from porcine pituitaries using a hot glacial acetic acid extraction method and was partially purified by gel filtration. When injected intraventricularly in rats, these purified peptides induced strong analgesia, catelepsy, respiratory depression and other opiate-like effects, which lasted for several hours. PMID:1034219

  20. Effect of partial agonist activity in beta blockers in severe angina pectoris: a double blind comparison of pindolol and atenolol.

    PubMed

    Quyyumi, A A; Wright, C; Mockus, L; Fox, K M

    1984-10-13

    The use of beta adrenoceptor blockade in the treatment of rest angina is controversial, and the effects on severe angina of partial agonist activity in beta blockers are unknown. Eight patients with effort angina and seven with effort and nocturnal angina and severe coronary artery disease were studied initially when they were not taking any antianginal drugs. Pindolol 5 mg thrice daily (with partial agonist activity) and atenolol 100 mg daily (without partial agonist activity) were given for five days each in a double blind randomised manner. Diaries of angina were kept and treadmill exercise testing and ambulatory ST monitoring performed during the last 48 hours of each period of treatment. Daytime and nocturnal resting heart rates and the frequency of angina were significantly reduced by atenolol compared with pindolol (p less than 0.01). The duration of exercise was significantly increased and the frequency, duration, and magnitude of daytime and nocturnal episodes of ST segment depression on ambulatory monitoring were reduced by atenolol. Reduction in resting heart rate is important in the treatment of both effort and nocturnal angina. Partial agonist activity in beta adrenoceptor antagonists may be deleterious in patients with severe angina pectoris. PMID:6148991

  1. Differential pathway coupling efficiency of the activated insulin receptor drives signaling selectivity by xmeta, an allosteric partial agonist antibody

    Technology Transfer Automated Retrieval System (TEKTRAN)

    XMetA, an anti-insulin receptor (IR) monoclonal antibody, is an allosteric partial agonist of the IR. We have previously reported that XMetA activates the “metabolic-biased” Akt kinase signaling pathway while having little or no effect on the “mitogenic” MAPK signaling pathwayof ERK 1/2. To inves...

  2. Partial root zone drying: regulation of photosynthetic limitations and antioxidant enzymatic activities in young olive (Olea europaea) saplings.

    PubMed

    Aganchich, Badia; Wahbi, Said; Loreto, Francesco; Centritto, Mauro

    2009-05-01

    The effect of partial root drying (PRD) irrigation on split-root olive (Olea europaea L. cv Picholine marocaine) saplings was investigated. An irrigated control and two PRD regimes were applied (control: irrigation applied on both sides of the root system to keep the soil water content close to field capacity; PRD(50): irrigation applied at 50% of the control amount on one side of the root system and irrigation withheld from the other side, with irrigation regimes switched between the sides of the root system every 2 weeks; and PRD(100): irrigation applied at 100% of the control amount on one side and irrigation withheld on the other side, with irrigation regimes switched between the sides of the root system every 2 weeks. Only saplings in the PRD(50) regime were subjected to water-deficit irrigation. The PRD treatments significantly affected water relations and vegetative growth throughout the growing season. Predawn leaf water potential and relative water content differed significantly between the PRD(50) and PRD(100) saplings, leading to reduced stomatal conductance, carbon assimilation, shoot length and leaf number in PRD(50) saplings. However, the PRD(50) water-deficit treatment did not affect the capacity of the saplings to assimilate CO(2). Activities of superoxide dismutase, soluble and insoluble peroxidase (POX) and polyphenol oxidase were up-regulated by the PRD(50) and PRD(100) treatments compared with control values. The higher activities of both soluble and insoluble POX observed in PRD(50) saplings may reflect the greater inhibitory effect of this treatment on vegetative growth. Up-regulation of the detoxifying systems in the PRD(100) and PRD(50) saplings may have provided protection mechanisms against irreversible damage to the photosynthetic machinery, thereby allowing the photosynthetic apparatus to function and preventing the development of severe water stress. We also measured CO(2) assimilation rate/internal leaf CO(2) concentration (A

  3. The Middeck Active Control Experiment (MACE): Identification for robust control

    NASA Astrophysics Data System (ADS)

    Karlov, Valery I.

    Viewgraphs on identification for robust control for the Middeck Active Control Experiment (MACE) are presented. Topics covered include: identification for robust control; three levels of identification; basic elements of the approach; advantages of 'post-ID' model of uncertainty; advantages of optimization; and practical realization.

  4. The Middeck Active Control Experiment (MACE): Identification for robust control

    NASA Technical Reports Server (NTRS)

    Karlov, Valery I.

    1992-01-01

    Viewgraphs on identification for robust control for the Middeck Active Control Experiment (MACE) are presented. Topics covered include: identification for robust control; three levels of identification; basic elements of the approach; advantages of 'post-ID' model of uncertainty; advantages of optimization; and practical realization.

  5. Aggregate size and architecture determine microbial activity balance for one-stage partial nitritation and anammox.

    PubMed

    Vlaeminck, Siegfried E; Terada, Akihiko; Smets, Barth F; De Clippeleir, Haydée; Schaubroeck, Thomas; Bolca, Selin; Demeestere, Lien; Mast, Jan; Boon, Nico; Carballa, Marta; Verstraete, Willy

    2010-02-01

    Aerobic ammonium-oxidizing bacteria (AerAOB) and anoxic ammonium-oxidizing bacteria (AnAOB) cooperate in partial nitritation/anammox systems to remove ammonium from wastewater. In this process, large granular microbial aggregates enhance the performance, but little is known about granulation so far. In this study, three suspended-growth oxygen-limited autotrophic nitrification-denitrification (OLAND) reactors with different inoculation and operation (mixing and aeration) conditions, designated reactors A, B, and C, were used. The test objectives were (i) to quantify the AerAOB and AnAOB abundance and the activity balance for the different aggregate sizes and (ii) to relate aggregate morphology, size distribution, and architecture putatively to the inoculation and operation of the three reactors. A nitrite accumulation rate ratio (NARR) was defined as the net aerobic nitrite production rate divided by the anoxic nitrite consumption rate. The smallest reactor A, B, and C aggregates were nitrite sources (NARR, >1.7). Large reactor A and C aggregates were granules capable of autonomous nitrogen removal (NARR, 0.6 to 1.1) with internal AnAOB zones surrounded by an AerAOB rim. Around 50% of the autotrophic space in these granules consisted of AerAOB- and AnAOB-specific extracellular polymeric substances. Large reactor B aggregates were thin film-like nitrite sinks (NARR, <0.5) in which AnAOB were not shielded by an AerAOB layer. Voids and channels occupied 13 to 17% of the anoxic zone of AnAOB-rich aggregates (reactors B and C). The hypothesized granulation pathways include granule replication by division and budding and are driven by growth and/or decay based on species-specific physiology and by hydrodynamic shear and mixing. PMID:19948857

  6. Application of a magnetohydrodynamic element in the control loop of a rotating spacecraft with cavities partially filled with liquid

    NASA Astrophysics Data System (ADS)

    Nazirov, R. R.; Rabinovich, B. I.; Mytarev, A. I.

    2008-06-01

    This paper is a continuation of [1 3] and a generalization of the results for a rotating spacecraft with cavities partially filled with liquid and equipped with an operational magnetohydrodynamic (MHD) element in the loop of its attitude control. This element makes possible the creation of hingeless systems of stabilization and orientation that do not require rocket propellant consumption. The application of an MHD element is considered for stabilization in the mode of spin-up of a spacecraft not having gyroscopic stability.

  7. Student Activity Funds: Procedures & Controls.

    ERIC Educational Resources Information Center

    Cuzzetto, Charles E.

    Student activity funds may create educational opportunities for students, but they frequently create problems for business administrators. The first part of this work reviews the types of organizational issues and transactions an organized student group is likely to encounter, including establishing a constitution, participant roles,…

  8. Parasympathetic activity and blood catecholamine responses following a single partial-body cryostimulation and a whole-body cryostimulation.

    PubMed

    Hausswirth, Christophe; Schaal, Karine; Le Meur, Yann; Bieuzen, François; Filliard, Jean-Robert; Volondat, Marielle; Louis, Julien

    2013-01-01

    The aim of this study was to compare the effects of a single whole-body cryostimulation (WBC) and a partial-body cryostimulation (PBC) (i.e., not exposing the head to cold) on indices of parasympathetic activity and blood catecholamines. Two groups of 15 participants were assigned either to a 3-min WBC or PBC session, while 10 participants constituted a control group (CON) not receiving any cryostimulation. Changes in thermal, physiological and subjective variables were recorded before and during the 20-min after each cryostimulation. According to a qualitative statistical analysis, an almost certain decrease in skin temperature was reported for all body regions immediately after the WBC (mean decrease±90% CL, -13.7±0.7°C) and PBC (-8.3±0.3°C), which persisted up to 20-min after the session. The tympanic temperature almost certainly decreased only after the WBC session (-0.32±0.04°C). Systolic and diastolic blood pressures were very likely increased after the WBC session, whereas these changes were trivial in the other groups. In addition, heart rate almost certainly decreased after PBC (-10.9%) and WBC (-15.2%) sessions, in a likely greater proportion for WBC compared to PBC. Resting vagal-related heart rate variability indices (the root-mean square difference of successive normal R-R intervals, RMSSD, and high frequency band, HF) were very likely increased after PBC (RMSSD: +54.4%, HF: +138%) and WBC (RMSSD: +85.2%, HF: +632%) sessions without any marked difference between groups. Plasma norepinephrine concentrations were likely to very likely increased after PBC (+57.4%) and WBC (+76.2%), respectively. Finally, cold and comfort sensations were almost certainly altered after WBC and PBC, sensation of discomfort being likely more pronounced after WBC than PBC. Both acute cryostimulation techniques effectively stimulated the autonomic nervous system (ANS), with a predominance of parasympathetic tone activation. The results of this study also suggest that a

  9. Parasympathetic Activity and Blood Catecholamine Responses Following a Single Partial-Body Cryostimulation and a Whole-Body Cryostimulation

    PubMed Central

    Hausswirth, Christophe; Schaal, Karine; Le Meur, Yann; Bieuzen, François; Filliard, Jean-Robert; Volondat, Marielle; Louis, Julien

    2013-01-01

    The aim of this study was to compare the effects of a single whole-body cryostimulation (WBC) and a partial-body cryostimulation (PBC) (i.e., not exposing the head to cold) on indices of parasympathetic activity and blood catecholamines. Two groups of 15 participants were assigned either to a 3-min WBC or PBC session, while 10 participants constituted a control group (CON) not receiving any cryostimulation. Changes in thermal, physiological and subjective variables were recorded before and during the 20-min after each cryostimulation. According to a qualitative statistical analysis, an almost certain decrease in skin temperature was reported for all body regions immediately after the WBC (mean decrease±90% CL, -13.7±0.7°C) and PBC (-8.3±0.3°C), which persisted up to 20-min after the session. The tympanic temperature almost certainly decreased only after the WBC session (-0.32±0.04°C). Systolic and diastolic blood pressures were very likely increased after the WBC session, whereas these changes were trivial in the other groups. In addition, heart rate almost certainly decreased after PBC (-10.9%) and WBC (-15.2%) sessions, in a likely greater proportion for WBC compared to PBC. Resting vagal-related heart rate variability indices (the root-mean square difference of successive normal R-R intervals, RMSSD, and high frequency band, HF) were very likely increased after PBC (RMSSD: +54.4%, HF: +138%) and WBC (RMSSD: +85.2%, HF: +632%) sessions without any marked difference between groups. Plasma norepinephrine concentrations were likely to very likely increased after PBC (+57.4%) and WBC (+76.2%), respectively. Finally, cold and comfort sensations were almost certainly altered after WBC and PBC, sensation of discomfort being likely more pronounced after WBC than PBC. Both acute cryostimulation techniques effectively stimulated the autonomic nervous system (ANS), with a predominance of parasympathetic tone activation. The results of this study also suggest that a

  10. Active-member control of precision structures

    NASA Technical Reports Server (NTRS)

    Fanson, J. L.; Blackwood, G. H.; Chu, C. C.

    1989-01-01

    This paper presents the results of closed loop experiments that use piezoelectric active-members to control the flexible motion of a precision truss structure. These experiments are directed toward the development of high performance structural systems as part of the Control/Structure Interaction program at JPL. Order of magnitude reductions in dynamic response are achieved with relatively simple control techniques. The practical implementation of high stiffness, high bandwidth active-members in a precision structure highlights specific issues of importance relating to the modelling and implementation of active-member control.

  11. Actively controlled shaft seals for aerospace applications

    NASA Technical Reports Server (NTRS)

    Salant, Richard F.

    1991-01-01

    Actively controlled mechanical seals have recently been developed for industrial use. This study investigates the feasibility of using such seals for aerospace applications. In a noncontacting mechanical seal, the film thickness depends on the geometry of the seal interface. The amount of coning, which is a measure of the radial convergence or divergence of the seal interface, has a primary effect on the film thickness. Active control of the film thickness is established by controlling the coning with a piezoelectric material. A mathematical model has been formulated to predict the performance of an actively controlled mechanical seal.

  12. Photoionization of Synchrotron-Radiation-Excited Atoms: Separating Partial Cross Sections by Full Polarization Control

    SciTech Connect

    Aloiese, S.; Meyer, M.; Cubaynes, D.; Grum-Grzhimailo, A. N.

    2005-06-10

    Resonant atomic excitation by synchrotron radiation and subsequent ionization by a tunable dye laser is used to study the photoionization of short-lived Rydberg states in Xe. By combining circular and linear polarization of the synchrotron as well as of the laser photons the partial photoionization cross sections were separated in the region of overlapping autoionizing resonances of different symmetry and the parameters of the resonances were extracted.

  13. Detachment Fault Initiation and Control by Partially Molten Zones in the Lower Ocean Crust

    NASA Astrophysics Data System (ADS)

    Dick, H. J.; Natland, J. H.; MacLeod, C. J.; Robinson, P. T.

    2012-12-01

    The close association of oxide gabbro and deformation in interleaved ferrogabbro and olivine gabbro at Atlantis Bank on the SW Indian Ridge explains the formation of this enormous single-domed gabbroic oceanic core complex. ODP Holes 735B and 1105A show that the stratigraphy is defined by 100's of zones of intense deformation and strain localization in the upper 500-m where various melts percolated including late-stage iron-titanium rich melts. The latter created highly deformed oxide-rich gabbro zones at scales from millimeters to over 100 meters. Mapping by ROV, over-the-side rock drilling, dredging, and submersible shows that this stratigraphy exists uniformly over the bank. Deep drilling and sampling up the headwalls of major landslips cutting into the core complex show that the fault zone was imbricate, likely reflecting relocation of the active slip plane due to cyclic intrusion in the lower crust. The detachment originated as a high-angle fault on the rift valley wall that propagated into a zone of partially molten gabbro beneath the sheeted dikes. This zone then pinned the footwall block, creating a plutonic growth fault along which gabbro intruded beneath the ridge axis was continuously uplifted and exposed on the Antarctic plate for ~3.9 myr. The overlying basaltic carapace spread more slowly to the north on the African Plate. Textural evidence, particularly that provided by iron-titanium oxides, shows that melts migrated along complex shear zones in which several creep mechanisms operated, ranging from crystal plastic dislocation creep, diffusion creep, grain boundary sliding, and brittle deformation. More than one of these mechanisms may have occurred concurrently. Subsequently, these zones localized later solid-state creep, often producing texturally complex rocks where separation of the timing and duration of different creep mechanisms is difficult to unravel. As uplift of the plutonic section progressed, the footwall passed through the zone of diking

  14. Active Control Of Structure-Borne Noise

    NASA Astrophysics Data System (ADS)

    Elliott, S. J.

    1994-11-01

    The successful practical application of active noise control requires an understanding of both its acoustic limitations and the limitations of the electrical control strategy used. This paper is concerned with the active control of sound in enclosures. First, a review is presented of the fundamental physical limitations of using loudspeakers to achieve either global or local control. Both approaches are seen to have a high frequency limit, due to either the acoustic modal overlap, or the spatial correlation function of the pressure field. These physical performance limits could, in principle, be achieved with either a feedback or a feedforward control strategy. These strategies are reviewed and the use of adaptive digital filters is discussed for both approaches. The application of adaptive feedforward control in the control of engine and road noise in cars is described. Finally, an indirect approach to the active control of sound is discussed, in which the vibration is suppressed in the structural paths connecting the source of vibration to the enclosure. Two specific examples of this strategy are described, using an active automotive engine mount and the incorporation of actuators into helicopter struts to control gear-meshing tones. In both cases good passive design can minimize the complexity of the active controller.

  15. Implications of partial immunity on the prospects for tuberculosis control by post-exposure interventions.

    PubMed

    Gabriela M Gomes, M; Rodrigues, Paula; Hilker, Frank M; Mantilla-Beniers, Natalia B; Muehlen, Marion; Cristina Paulo, Ana; Medley, Graham F

    2007-10-21

    One-third of the world population (approximately 2 billion individuals) is currently infected with Mycobacterium tuberculosis, the vast majority harboring a latent infection. As the risk of reactivation is around 10% in a lifetime, it follows that 200 million of these will eventually develop active pulmonary disease. Only therapeutic or post-exposure interventions can tame this vast reservoir of infection. Treatment of latent infections can reduce the risk of reactivation, and there is accumulating evidence that combination with post-exposure vaccines can reduce the risk of reinfection. Here we develop mathematical models to explore the potential of these post-exposure interventions to control tuberculosis on a global scale. Intensive programs targeting recent infections appear generally effective, but the benefit is potentially greater in intermediate prevalence scenarios. Extending these strategies to longer-term persistent infections appears more beneficial where prevalence is low. Finally, we consider that susceptibility to reinfection is altered by therapy, and explore its epidemiological consequences. When we assume that therapy reduces susceptibility to subsequent reinfection, catastrophic dynamics are observed. Thus, a bipolar outcome is obtained, where either small or large reductions in prevalence levels result, depending on the rate of detection and treatment of latent infections. By contrast, increased susceptibility after therapy may induce an increase in disease prevalence and does not lead to catastrophic dynamics. These potential outcomes are silent unless a widespread intervention is implemented. PMID:17669435

  16. Insulin down-regulates the expression of ubiquitin E3 ligases partially by inhibiting the activity and expression of AMP-activated protein kinase in L6 myotubes

    PubMed Central

    Deng, Hu-Ping; Chai, Jia-Ke; Shen, Chuan-An; Zhang, Xi-Bo; Ma, Li; Sun, Tian-Jun; Hu, Qing-Gang; Chi, Yun-Fei; Dong, Ning

    2015-01-01

    While insulin is an anabolic hormone, AMP-activated protein kinase (AMPK) is not only a key energy regulator, but it can also control substrate metabolism directly by inducing skeletal muscle protein degradation. The hypothesis of the present study was that insulin inhibits AMPK and thus down-regulates the expression of the ubiquitin E3 ligases, muscle atrophy F-box (MAFbx) and muscle RING finger 1 (MuRF1) in skeletal muscle cells. Differentiated L6 myotubes were treated with 5-aminoimidazole-4-carboxamide-1-β-4-ribofuranoside (AICAR) and/or compound C to stimulate and/or block AMPK respectively. These treatments were also conducted in the presence or absence of insulin and the cells were analysed by western blot and quantitative real-time PCR. In addition, nuleotide levels were determined using HPLC. The activation of AMPK with AICAR enhanced the mRNA levels of MAFbx and MuRF1. Insulin reduced the phosphorylation and activity AMPK, which was accompanied by reduced MAFbx and MuRF1 mRNA levels. Using a protein kinase B (PKB/Akt) inhibitor, we found that insulin regulates AMPK through the activation of Akt. Furthermore, insulin down-regulated AMPK α2 mRNA. We conclude that insulin inhibits AMPK through Akt phosphorylation in L6 myotubes, which may serve as a possible signalling pathway for the down-regulation of protein degradation. In addition, decreased expression of AMPK α2 may partially participate in inhibiting the activity of AMPK. PMID:26193886

  17. Selected topics on the active control of helicopter aeromechanical and vibration problems

    NASA Technical Reports Server (NTRS)

    Friedmann, Peretz P.

    1994-01-01

    This paper describes in a concise manner three selected topics on the active control of helicopter aeromechanical and vibration problems. The three topics are as follows: (1) the active control of helicopter air-resonance using an LQG/LTR approach; (2) simulation of higher harmonic control (HHC) applied to a four bladed hingeless helicopter rotor in forward flight; and (3) vibration suppression in forward flight on a hingeless helicopter rotor using an actively controlled, partial span, trailing edge flap, which is mounted on the blade. Only a few selected illustrative results are presented. The results obtained clearly indicate that the partial span, actively controlled flap has considerable potential for vibration reduction in helicopter rotors.

  18. Active vibration control of lightweight floor systems

    NASA Astrophysics Data System (ADS)

    Baader, J.; Fontana, M.

    2016-04-01

    Wide-span and lightweight floors are often prone to structural vibrations due to their low resonance frequency and poor material damping. Their dynamic behaviour can be improved using passive, semi-active or active vibration control devices. The following article proposes a novel method for the controller synthesis for active vibration control. An existing passive TMD (tuned mass damper) is modelled and equipped with an actuator in order to provide more efficient damping. Using an iterative optimization approach under constraints, an optimal controller is found which minimizes a quadratic cost function in frequency domain. A simulation of an existing test bench shows that the active vibration control device is able to provide increased damping compared to the passive TMD.

  19. Partially oxidized iridium clusters within dendrimers: size-controlled synthesis and selective hydrogenation of 2-nitrobenzaldehyde.

    PubMed

    Higaki, Tatsuya; Kitazawa, Hirokazu; Yamazoe, Seiji; Tsukuda, Tatsuya

    2016-06-01

    Iridium clusters nominally composed of 15, 30 or 60 atoms were size-selectively synthesized within OH-terminated poly(amidoamine) dendrimers of generation 6. Spectroscopic characterization revealed that the Ir clusters were partially oxidized. All the Ir clusters efficiently converted 2-nitrobenzaldehyde to anthranil and 2-aminobenzaldehyde under atmospheric hydrogen at room temperature in toluene via selective hydrogenation of the NO2 group. The selectivity toward 2-aminobenzaldehyde over anthranil was improved with the reduction of the cluster size. The improved selectivity is ascribed to more efficient reduction than intramolecular heterocyclization of a hydroxylamine intermediate on smaller clusters that have a higher Ir(0)-phase population on the surface. PMID:27193739

  20. Charged particle detectors with active detector surface for partial energy deposition of the charged particles and related methods

    DOEpatents

    Gerts, David W; Bean, Robert S; Metcalf, Richard R

    2013-02-19

    A radiation detector is disclosed. The radiation detector comprises an active detector surface configured to generate charge carriers in response to charged particles associated with incident radiation. The active detector surface is further configured with a sufficient thickness for a partial energy deposition of the charged particles to occur and permit the charged particles to pass through the active detector surface. The radiation detector further comprises a plurality of voltage leads coupled to the active detector surface. The plurality of voltage leads is configured to couple to a voltage source to generate a voltage drop across the active detector surface and to separate the charge carriers into a plurality of electrons and holes for detection. The active detector surface may comprise one or more graphene layers. Timing data between active detector surfaces may be used to determine energy of the incident radiation. Other apparatuses and methods are disclosed herein.

  1. Reliable and Affordable Control Systems Active Combustor Pattern Factor Control

    NASA Technical Reports Server (NTRS)

    McCarty, Bob; Tomondi, Chris; McGinley, Ray

    2004-01-01

    Active, closed-loop control of combustor pattern factor is a cooperative effort between Honeywell (formerly AlliedSignal) Engines and Systems and the NASA Glenn Research Center to reduce emissions and turbine-stator vane temperature variations, thereby enhancing engine performance and life, and reducing direct operating costs. Total fuel flow supplied to the engine is established by the speed/power control, but the distribution to individual atomizers will be controlled by the Active Combustor Pattern Factor Control (ACPFC). This system consist of three major components: multiple, thin-film sensors located on the turbine-stator vanes; fuel-flow modulators for individual atomizers; and control logic and algorithms within the electronic control.

  2. Partially oxidized iridium clusters within dendrimers: size-controlled synthesis and selective hydrogenation of 2-nitrobenzaldehyde

    NASA Astrophysics Data System (ADS)

    Higaki, Tatsuya; Kitazawa, Hirokazu; Yamazoe, Seiji; Tsukuda, Tatsuya

    2016-06-01

    Iridium clusters nominally composed of 15, 30 or 60 atoms were size-selectively synthesized within OH-terminated poly(amidoamine) dendrimers of generation 6. Spectroscopic characterization revealed that the Ir clusters were partially oxidized. All the Ir clusters efficiently converted 2-nitrobenzaldehyde to anthranil and 2-aminobenzaldehyde under atmospheric hydrogen at room temperature in toluene via selective hydrogenation of the NO2 group. The selectivity toward 2-aminobenzaldehyde over anthranil was improved with the reduction of the cluster size. The improved selectivity is ascribed to more efficient reduction than intramolecular heterocyclization of a hydroxylamine intermediate on smaller clusters that have a higher Ir(0)-phase population on the surface.Iridium clusters nominally composed of 15, 30 or 60 atoms were size-selectively synthesized within OH-terminated poly(amidoamine) dendrimers of generation 6. Spectroscopic characterization revealed that the Ir clusters were partially oxidized. All the Ir clusters efficiently converted 2-nitrobenzaldehyde to anthranil and 2-aminobenzaldehyde under atmospheric hydrogen at room temperature in toluene via selective hydrogenation of the NO2 group. The selectivity toward 2-aminobenzaldehyde over anthranil was improved with the reduction of the cluster size. The improved selectivity is ascribed to more efficient reduction than intramolecular heterocyclization of a hydroxylamine intermediate on smaller clusters that have a higher Ir(0)-phase population on the surface. Electronic supplementary information (ESI) available. See DOI: 10.1039/c6nr01460g

  3. Active Control by Conservation of Energy Concept

    NASA Technical Reports Server (NTRS)

    Maestrello, Lucio

    2000-01-01

    Three unrelated experiments are discussed; each was extremely sensitive to initial conditions. The initial conditions are the beginnings of the origins of the information that nonlinearity displays. Initial conditions make the phenomenon unstable and unpredictable. With the knowledge of the initial conditions, active control requires far less power than that present in the system response. The first experiment is on the control of shocks from an axisymmetric supersonic jet; the second, control of a nonlinear panel response forced by turbulent boundary layer and sound; the third, control of subharmonic and harmonics of a panel forced by sound. In all three experiments, control is achieved by redistribution of periodic energy response such that the energy is nearly preserved from a previous uncontrolled state. This type of active control improves the performance of the system being controlled.

  4. Magnetic motive, ordered mesoporous carbons with partially graphitized framework and controllable surface wettability: preparation, characterization and their selective adsorption of organic pollutants in water

    NASA Astrophysics Data System (ADS)

    Zhang, Bin; Liu, Chen; Kong, Weiping; Qi, Chenze

    2016-06-01

    Magnetically active, ordered and stable mesoporous carbons with partially graphitized networks and controllable surface wettability (PR-Fe-P123-800 and PR-Ni-P123-800) have been synthesized through direct carbonization of Fe or Ni functionalized, and ordered mesoporous polymers at 800°C, which could be synthesized from self assembly of resol (phenol/formaldehyde) with block copolymer template (P123) in presence of Fe3+ or Ni2+, and hydrothermal treatment at 200°C. PR-Fe-P123-800 and PR-Ni-P123-800 possess ordered and uniform mesopores, large BET surface areas, good stabilities, controllable surface wettability and partially graphitized framework. The above structural characteristics result in their enhanced selective adsorption property and good reusability for organic pollutants such as RhB, p-nitrophenol and n-heptane in water, which could be easily regenerated through separation under constant magnetic fields and washing with ethanol solvent. The unique magnetically active and adsorptive property found in PR-Fe-P123-800 and PR-Ni-P123-800 will be very important for them to be used as efficient absorbents for removal of various organic pollutants in water.

  5. Magnetic motive, ordered mesoporous carbons with partially graphitized framework and controllable surface wettability: preparation, characterization and their selective adsorption of organic pollutants in water

    NASA Astrophysics Data System (ADS)

    Zhang, Bin; Liu, Chen; Kong, Weiping; Qi, Chenze

    2016-02-01

    Magnetically active, ordered and stable mesoporous carbons with partially graphitized networks and controllable surface wettability (PR-Fe-P123-800 and PR-Ni-P123-800) have been synthesized through direct carbonization of Fe or Ni functionalized, and ordered mesoporous polymers at 800°C, which could be synthesized from self assembly of resol (phenol/formaldehyde) with block copolymer template (P123) in presence of Fe3+ or Ni2+, and hydrothermal treatment at 200°C. PR-Fe-P123-800 and PR-Ni-P123-800 possess ordered and uniform mesopores, large BET surface areas, good stabilities, controllable surface wettability and partially graphitized framework. The above structural characteristics result in their enhanced selective adsorption property and good reusability for organic pollutants such as RhB, p-nitrophenol and n-heptane in water, which could be easily regenerated through separation under constant magnetic fields and washing with ethanol solvent. The unique magnetically active and adsorptive property found in PR-Fe-P123-800 and PR-Ni-P123-800 will be very important for them to be used as efficient absorbents for removal of various organic pollutants in water.

  6. Active control of buildings during earthquakes

    NASA Technical Reports Server (NTRS)

    Vance, Vicki L.

    1993-01-01

    The objective of this report is to provide an overview of the different types of control systems used in buildings, to discuss the problems associated with current active control mechanisms, and to show the cost-effectiveness of applying active control to buildings. In addition, a small case study investigates the feasibility and benefits of using embedded actuators in buildings. Use of embedded actuators could solve many of the current problems associated with active control by providing a wider bandwidth of control, quicker speed of response, increased reliability and reduced power requirement. Though embedded actuators have not been developed for buildings, they have previously been used in space structures. Many similarities exist between large civil and aerospace structures indicating that direct transfer of concepts between the two disciplines may be possible. In particular, much of the Controls-Structures Interaction (CSI) technology currently being developed could be beneficially applied to civil structures. While several buildings with active control systems have been constructed in Japan, additional research and experimental verification are necessary before active control systems become widely accepted and implemented.

  7. Manually controlled neutron-activation system

    NASA Astrophysics Data System (ADS)

    Johns, R. A.; Carothers, G. A.

    1982-01-01

    A manually controlled neutron activation system, the Manual Reactor Activation System, was designed and built and has been operating at one of the Savannah River Plant's production reactors. With this system, samples can be irradiated for up to 24 hours and pneumatically transferred to a shielded repository for decay until their activity is low enough for them to be handled at a radiobench. The Manual Reactor Activation System was built to provide neutron activation of solid waste forms for the Alternative Waste Forms Leach Testing Program. Neutron activation of the bulk sample prior to leaching permits sensitive multielement radiometric analyses of the leachates.

  8. Combined and controlled remote implementations of partially unknown quantum operations of multiqubits using Greenberger-Horne-Zeilinger states

    SciTech Connect

    Wang Anmin

    2007-06-15

    We propose and prove protocols of combined and controlled remote implementations of partially unknown quantum operations belonging to the restricted sets [A. M. Wang, Phys. Rev. A 74, 032317 (2006)] using Greenberger-Horne-Zeilinger (GHZ) states. We present the protocols in detail in the cases of one qubit, with two senders and with one controller, respectively. Then we study the variations of protocols with many senders, or with many controllers, or with both many senders and controllers using a multipartite GHZ state. Furthermore, we extend these protocols to the cases of multiqubits. Because our protocols have to request that the senders work together and transfer the information in turn or receive the repertoire of extra supercontrollers, or/and the controller(s) open the quantum channel and distribute the passwords in different ways, they definitely have the strong security in remote quantum information processing and communications. Moreover, the combined protocol with many senders is helpful to arrive at the power of remote implementations of quantum operations to the utmost extent in theory, since the different senders may have different operational resources and different operational rights in practice, and the controlled protocol with many controllers is able to enhance security and increase applications of remote implementations of quantum operations in engineering, since it has some common features in a controlled process.

  9. Combined and controlled remote implementations of partially unknown quantum operations of multiqubits using Greenberger-Horne-Zeilinger states

    NASA Astrophysics Data System (ADS)

    Wang, An Min

    2007-06-01

    We propose and prove protocols of combined and controlled remote implementations of partially unknown quantum operations belonging to the restricted sets [A. M. Wang, Phys. Rev. A 74, 032317 (2006)] using Greenberger-Horne-Zeilinger (GHZ) states. We present the protocols in detail in the cases of one qubit, with two senders and with one controller, respectively. Then we study the variations of protocols with many senders, or with many controllers, or with both many senders and controllers using a multipartite GHZ state. Furthermore, we extend these protocols to the cases of multiqubits. Because our protocols have to request that the senders work together and transfer the information in turn or receive the repertoire of extra supercontrollers, or/and the controller(s) open the quantum channel and distribute the passwords in different ways, they definitely have the strong security in remote quantum information processing and communications. Moreover, the combined protocol with many senders is helpful to arrive at the power of remote implementations of quantum operations to the utmost extent in theory, since the different senders may have different operational resources and different operational rights in practice, and the controlled protocol with many controllers is able to enhance security and increase applications of remote implementations of quantum operations in engineering, since it has some common features in a controlled process.

  10. Neural network approach to continuous-time direct adaptive optimal control for partially unknown nonlinear systems.

    PubMed

    Vrabie, Draguna; Lewis, Frank

    2009-04-01

    In this paper we present in a continuous-time framework an online approach to direct adaptive optimal control with infinite horizon cost for nonlinear systems. The algorithm converges online to the optimal control solution without knowledge of the internal system dynamics. Closed-loop dynamic stability is guaranteed throughout. The algorithm is based on a reinforcement learning scheme, namely Policy Iterations, and makes use of neural networks, in an Actor/Critic structure, to parametrically represent the control policy and the performance of the control system. The two neural networks are trained to express the optimal controller and optimal cost function which describes the infinite horizon control performance. Convergence of the algorithm is proven under the realistic assumption that the two neural networks do not provide perfect representations for the nonlinear control and cost functions. The result is a hybrid control structure which involves a continuous-time controller and a supervisory adaptation structure which operates based on data sampled from the plant and from the continuous-time performance dynamics. Such control structure is unlike any standard form of controllers previously seen in the literature. Simulation results, obtained considering two second-order nonlinear systems, are provided. PMID:19362449

  11. Controls on fire activity over the Holocene

    NASA Astrophysics Data System (ADS)

    Kloster, S.; Brucher, T.; Brovkin, V.; Wilkenskjeld, S.

    2015-05-01

    Changes in fire activity over the last 8000 years are simulated with a global fire model driven by changes in climate and vegetation cover. The changes were separated into those caused through variations in fuel availability, fuel moisture or wind speed, which react differently to changes in climate. Disentangling these controlling factors helps in understanding the overall climate control on fire activity over the Holocene. Globally the burned area is simulated to increase by 2.5% between 8000 and 200 cal yr BP, with larger regional changes compensating nearly evening out on a global scale. Despite the absence of anthropogenic fire ignitions, the simulated trends in fire activity agree reasonably well with continental-scale reconstructions from charcoal records, with the exception of Europe. For some regions the change in fire activity is predominantly controlled through changes in fuel availability (Australia monsoon, Central America tropics/subtropics). For other regions changes in fuel moisture are more important for the overall trend in fire activity (North America, Sub-Saharan Africa, Europe, Asia monsoon). In Sub-Saharan Africa, for example, changes in fuel moisture alone lead to an increase in fire activity between 8000 and 200 cal yr BP, while changes in fuel availability lead to a decrease. Overall, the fuel moisture control is dominating the simulated fire activity for Sub-Saharan Africa. The simulations clearly demonstrate that both changes in fuel availability and changes in fuel moisture are important drivers for the fire activity over the Holocene. Fuel availability and fuel moisture do, however, have different climate controls. As such, observed changes in fire activity cannot be related to single climate parameters such as precipitation or temperature alone. Fire models, as applied in this study, in combination with observational records can help in understanding the climate control on fire activity, which is essential to project future fire

  12. ACTIVELY CONTROLLED AFTERBURNER FOR COMPACT WASTE INCINERATION

    EPA Science Inventory

    In a continuing research program directed at developing technology for compact shipboard incinerators, active control of fluid dynamics has been used to enhance mixing in incinerator afterburner (AB) experiments and increase the DRE for a waste surrogate. Experiments were conduc...

  13. The Middeck Active Control Experiment (MACE)

    NASA Astrophysics Data System (ADS)

    Miller, David W.

    1991-07-01

    Viewgraphs on the Middeck Active Control Experiment (MACE) are presented. Topics covered include: science program objectives and rationale; science requirements; capturing the essential physics; science development approach; development model hardware; development model test plan; and flight hardware and operations.

  14. The Middeck Active Control Experiment (MACE)

    NASA Technical Reports Server (NTRS)

    Miller, David W.

    1991-01-01

    Viewgraphs on the Middeck Active Control Experiment (MACE) are presented. Topics covered include: science program objectives and rationale; science requirements; capturing the essential physics; science development approach; development model hardware; development model test plan; and flight hardware and operations.

  15. Active control of turbomachine discrete tones

    NASA Astrophysics Data System (ADS)

    Fleeter, Sanford

    This paper was directed at active control of discrete frequency noise generated by subsonic blade rows through cancellation of the blade row interaction generated propagating acoustic waves. First discrete frequency noise generated by a rotor and stator in a duct was analyzed to determine the propagating acoustic pressure waves. Then a mathematical model was developed to analyze and predict the active control of discrete frequency noise generated by subsonic blade rows through cancellation of the propagating acoustic waves, accomplished by utilizing oscillating airfoil surfaces to generate additional control propagating pressure waves. These control waves interact with the propagating acoustic waves, thereby, in principle, canceling the acoustic waves and thus, the far field discrete frequency tones. This model was then applied to a fan exit guide vane to investigate active airfoil surface techniques for control of the propagating acoustic waves, and thus the far field discrete frequency tones, generated by blade row interactions.

  16. Synthesis and structure-activity relationships of novel indazolyl glucocorticoid receptor partial agonists.

    PubMed

    Gilmore, John L; Sheppeck, James E; Wang, Jim; Dhar, T G Murali; Cavallaro, Cullen; Doweyko, Arthur M; Mckay, Lorraine; Cunningham, Mark D; Habte, Sium F; Nadler, Steven G; Dodd, John H; Somerville, John E; Barrish, Joel C

    2013-10-01

    SAR was used to further develop an indazole class of non-steroidal glucocorticoid receptor agonists aided by a GR LBD (ligand-binding domain)-agonist co-crystal structure described in the accompanying paper. Progress towards discovering a dissociated GR agonist guided by human in vitro assays biased the optimization of this compound series towards partial agonists that possessed excellent selectivity against other nuclear hormone receptors. PMID:23916594

  17. Partial Storage Optimization and Load Control Strategy of Cloud Data Centers

    PubMed Central

    2015-01-01

    We present a novel approach to solve the cloud storage issues and provide a fast load balancing algorithm. Our approach is based on partitioning and concurrent dual direction download of the files from multiple cloud nodes. Partitions of the files are saved on the cloud rather than the full files, which provide a good optimization to the cloud storage usage. Only partial replication is used in this algorithm to ensure the reliability and availability of the data. Our focus is to improve the performance and optimize the storage usage by providing the DaaS on the cloud. This algorithm solves the problem of having to fully replicate large data sets, which uses up a lot of precious space on the cloud nodes. Reducing the space needed will help in reducing the cost of providing such space. Moreover, performance is also increased since multiple cloud servers will collaborate to provide the data to the cloud clients in a faster manner. PMID:25973444

  18. Partial storage optimization and load control strategy of cloud data centers.

    PubMed

    Al Nuaimi, Klaithem; Mohamed, Nader; Al Nuaimi, Mariam; Al-Jaroodi, Jameela

    2015-01-01

    We present a novel approach to solve the cloud storage issues and provide a fast load balancing algorithm. Our approach is based on partitioning and concurrent dual direction download of the files from multiple cloud nodes. Partitions of the files are saved on the cloud rather than the full files, which provide a good optimization to the cloud storage usage. Only partial replication is used in this algorithm to ensure the reliability and availability of the data. Our focus is to improve the performance and optimize the storage usage by providing the DaaS on the cloud. This algorithm solves the problem of having to fully replicate large data sets, which uses up a lot of precious space on the cloud nodes. Reducing the space needed will help in reducing the cost of providing such space. Moreover, performance is also increased since multiple cloud servers will collaborate to provide the data to the cloud clients in a faster manner. PMID:25973444

  19. Active Polymer Microfiber with Controlled Polarization Sensitivity

    PubMed Central

    Xia, Hongyan; Wang, Ruxue; Liu, Yingying; Cheng, Junjie; Zou, Gang; Zhang, Qijin; Zhang, Douguo; Wang, Pei; Ming, Hai; Badugu, Ramachandram; Lakowicz, Joseph R.

    2016-01-01

    Controlled Polarization Sensitivity of an active polymer microfiber has been proposed and realized with the electrospun method. The fluorescence intensity guiding through this active polymer microfiber shows high sensitivity to the polarization state of the excitation light. What is more, the fluorescence out-coupled from tip of the microfiber can be of designed polarization state. Principle of these phenomena lies on the ordered and controlled orientation of the polydiacetylene (PDA) main chains inside polymer microfiber. PMID:27099828

  20. Active control of helicopter transmission noise

    NASA Astrophysics Data System (ADS)

    Spencer, R. H.; Burke, M. J.; Tye, G. W.

    An account is given of an effort to reduce helicopter transmission noise by 10 dB, using active methods, as part of the NASA-Lewis/U.S. Army Propulsion Directorate Advanced Rotorcraft Transmission technology integration and demonstration program. The transmission used as a test stand is that of the CH-47C forward rotor. Attention is presently given to the active control system's actuators, sensors, and control algorithms.

  1. Active control of helicopter transmission noise

    NASA Technical Reports Server (NTRS)

    Spencer, R. H.; Burke, M. J.; Tye, G. W.

    1991-01-01

    An account is given of an effort to reduce helicopter transmission noise by 10 dB, using active methods, as part of the NASA-Lewis/U.S. Army Propulsion Directorate Advanced Rotorcraft Transmission technology integration and demonstration program. The transmission used as a test stand is that of the CH-47C forward rotor. Attention is presently given to the active control system's actuators, sensors, and control algorithms.

  2. Changes in neuronal activity and gene expression in guinea-pig auditory brainstem after unilateral partial hearing loss.

    PubMed

    Dong, S; Mulders, W H A M; Rodger, J; Robertson, D

    2009-03-31

    Spontaneous neural hyperactivity in the central auditory pathway is often associated with deafness, the most common form of which is partial hearing loss. We quantified both peripheral hearing loss and spontaneous activity in single neurons of the contralateral inferior colliculus in a guinea-pig model 1 week after a unilateral partial deafness induced by cochlear mechanical lesion. We also measured mRNA levels of candidate genes in the same animals using quantitative real-time PCR. Spontaneous hyperactivity was most marked in the frequency region of the peripheral hearing loss. Expression of glutamate decarboxylase 1 (GAD1), GABA-A receptor subunit alpha-1 (GABRA1), and potassium channel subfamily K member 15 (KCNK15) was decreased ipsilaterally in the cochlear nucleus and bilaterally in the inferior colliculus. A member of RAB family of small GTPase (RAB3A) was decreased in both ipsilateral cochlear nucleus and contralateral inferior colliculus. RAB3 GTPase activating protein subunit 1 (RAB3GAP1) and glycine receptor subunit alpha-1 (GLRA1) were reduced ipsilaterally in the cochlear nucleus only. These results suggest that a decrease in inhibitory neurotransmission and an increase in membrane excitability may contribute to elevated neuronal spontaneous activity in the auditory brainstem following unilateral partial hearing loss. PMID:19356697

  3. Vector control activities, fiscal year 1983

    SciTech Connect

    Pickard, E.; Cooney, J.C.; McDuff, B.R.

    1984-07-01

    The goal of the Vector Control Program is to safeguard public health and well-being in the Tennessee Valley region by controlling arthropod pests of medical importance that are propagated on TVA lands or waters or that are produced as a result of TVA activities. To achieve this goal the program is divided into two major categories consisting of operations and support studies. The latter is geared to improving the operational effectiveness and efficiency of the control program and to identify additional vector control problems requiring TVA attention and study. Nonchemical methods of control are emphasized and are supplemented with chemical measures as needed.

  4. Finite difference numerical methods for boundary control problems governed by hyperbolic partial differential equations

    NASA Technical Reports Server (NTRS)

    Chen, G.; Zheng, Q.; Coleman, M.; Weerakoon, S.

    1983-01-01

    This paper briefly reviews convergent finite difference schemes for hyperbolic initial boundary value problems and their applications to boundary control systems of hyperbolic type which arise in the modelling of vibrations. These difference schemes are combined with the primal and the dual approaches to compute the optimal control in the unconstrained case, as well as the case when the control is subject to inequality constraints. Some of the preliminary numerical results are also presented.

  5. Method and system for controlling a gasification or partial oxidation process

    SciTech Connect

    Rozelle, Peter L; Der, Victor K

    2015-02-10

    A method and system for controlling a fuel gasification system includes optimizing a conversion of solid components in the fuel to gaseous fuel components, controlling the flux of solids entrained in the product gas through equipment downstream of the gasifier, and maximizing the overall efficiencies of processes utilizing gasification. A combination of models, when utilized together, can be integrated with existing plant control systems and operating procedures and employed to develop new control systems and operating procedures. Such an approach is further applicable to gasification systems that utilize both dry feed and slurry feed.

  6. Transitioning Active Flow Control to Applications

    NASA Technical Reports Server (NTRS)

    Joslin, Ronald D.; Horta, Lucas G.; Chen, Fang-Jenq

    1999-01-01

    Active Flow Control Programs at NASA, the U.S. Air Force, and DARPA have been initiated with the goals of obtaining revolutionary advances in aerodynamic performance and maneuvering compared to conventional approaches. These programs envision the use of actuators, sensors, and controllers on applications such as aircraft wings/tails, engine nacelles, internal ducts, nozzles, projectiles, weapons bays, and hydrodynamic vehicles. Anticipated benefits of flow control include reduced weight, part count, and operating cost and reduced fuel burn (and emissions), noise and enhanced safety if the sensors serve a dual role of flow control and health monitoring. To get from the bench-top or laboratory test to adaptive distributed control systems on realistic applications, reliable validated design tools are needed in addition to sub- and large-scale wind-tunnel and flight experiments. This paper will focus on the development of tools for active flow control applications.

  7. Active load control techniques for wind turbines.

    SciTech Connect

    van Dam, C.P.; Berg, Dale E.; Johnson, Scott J.

    2008-07-01

    This report provides an overview on the current state of wind turbine control and introduces a number of active techniques that could be potentially used for control of wind turbine blades. The focus is on research regarding active flow control (AFC) as it applies to wind turbine performance and loads. The techniques and concepts described here are often described as 'smart structures' or 'smart rotor control'. This field is rapidly growing and there are numerous concepts currently being investigated around the world; some concepts already are focused on the wind energy industry and others are intended for use in other fields, but have the potential for wind turbine control. An AFC system can be broken into three categories: controls and sensors, actuators and devices, and the flow phenomena. This report focuses on the research involved with the actuators and devices and the generated flow phenomena caused by each device.

  8. Student Activity Funds: Procedures and Controls.

    ERIC Educational Resources Information Center

    Cuzzetto, Charles E.

    2000-01-01

    An effective internal-control system can help school business administrators meet the challenges of accounting for student activity funds. Such a system should include appropriate policies and procedures, identification of key control points, self-assessments, audit trails, and internal and external audits. (MLH)

  9. Oxidative stability and antioxidant enzyme activities of dry-cured bacons as affected by the partial substitution of NaCl with KCl.

    PubMed

    Wu, Haizhou; Yan, Wenjing; Zhuang, Hong; Huang, Mingming; Zhao, Jianying; Zhang, Jianhao

    2016-06-15

    This study investigated the influence of partial substitution of NaCl with KCl on protein and lipid oxidation as well as antioxidant enzyme activities in dry-cured bacons during processing. The partial substitution was 0% KCl (I), 40% KCl (II), and 70% KCl (III). Compared with 0% KCl (I), the substitution of 40% NaCl with KCl did not significantly influence the protein and lipid oxidation and antioxidant enzyme activities. The bacons that were treated with 70% KCl treatment (III) showed increased lipid oxidation and antioxidant enzyme GSH-Px activity, whereas samples treated with formulas I and II showed higher protein oxidation and antioxidant enzyme catalase activity. These results demonstrate that the substitution of NaCl with KCl by more than 40% may significantly affect protein and lipid oxidation and that for the substitution of NaCl in further processed meat products with other chloride salts, salt content is very important for control of protein and lipid biochemical changes in finished products. PMID:26868571

  10. Optimal active control for Burgers equations

    NASA Technical Reports Server (NTRS)

    Ikeda, Yutaka

    1994-01-01

    A method for active fluid flow control based on control theory is discussed. Dynamic programming and fixed point successive approximations are used to accommodate the nonlinear control problem. The long-term goal of this project is to establish an effective method applicable to complex flows such as turbulence and jets. However, in this report, the method is applied to stochastic Burgers equation as an intermediate step towards this goal. Numerical results are compared with those obtained by gradient search methods.

  11. Intention-to-Treat Analysis in Partially Nested Randomized Controlled Trials with Real-World Complexity

    ERIC Educational Resources Information Center

    Schweig, Jonathan David; Pane, John F.

    2016-01-01

    Demands for scientific knowledge of what works in educational policy and practice has driven interest in quantitative investigations of educational outcomes, and randomized controlled trials (RCTs) have proliferated under these conditions. In educational settings, even when individuals are randomized, both experimental and control students are…

  12. Partial Activation of SA- and JA-Defensive Pathways in Strawberry upon Colletotrichum acutatum Interaction.

    PubMed

    Amil-Ruiz, Francisco; Garrido-Gala, José; Gadea, José; Blanco-Portales, Rosario; Muñoz-Mérida, Antonio; Trelles, Oswaldo; de Los Santos, Berta; Arroyo, Francisco T; Aguado-Puig, Ana; Romero, Fernando; Mercado, José-Ángel; Pliego-Alfaro, Fernando; Muñoz-Blanco, Juan; Caballero, José L

    2016-01-01

    Understanding the nature of pathogen host interaction may help improve strawberry (Fragaria × ananassa) cultivars. Plant resistance to pathogenic agents usually operates through a complex network of defense mechanisms mediated by a diverse array of signaling molecules. In strawberry, resistance to a variety of pathogens has been reported to be mostly polygenic and quantitatively inherited, making it difficult to associate molecular markers with disease resistance genes. Colletotrichum acutatum spp. is a major strawberry pathogen, and completely resistant cultivars have not been reported. Moreover, strawberry defense network components and mechanisms remain largely unknown and poorly understood. Assessment of the strawberry response to C. acutatum included a global transcript analysis, and acidic hormones SA and JA measurements were analyzed after challenge with the pathogen. Induction of transcripts corresponding to the SA and JA signaling pathways and key genes controlling major steps within these defense pathways was detected. Accordingly, SA and JA accumulated in strawberry after infection. Contrastingly, induction of several important SA, JA, and oxidative stress-responsive defense genes, including FaPR1-1, FaLOX2, FaJAR1, FaPDF1, and FaGST1, was not detected, which suggests that specific branches in these defense pathways (those leading to FaPR1-2, FaPR2-1, FaPR2-2, FaAOS, FaPR5, and FaPR10) were activated. Our results reveal that specific aspects in SA and JA dependent signaling pathways are activated in strawberry upon interaction with C. acutatum. Certain described defense-associated transcripts related to these two known signaling pathways do not increase in abundance following infection. This finding suggests new insight into a specific putative molecular strategy for defense against this pathogen. PMID:27471515

  13. Partial Activation of SA- and JA-Defensive Pathways in Strawberry upon Colletotrichum acutatum Interaction

    PubMed Central

    Amil-Ruiz, Francisco; Garrido-Gala, José; Gadea, José; Blanco-Portales, Rosario; Muñoz-Mérida, Antonio; Trelles, Oswaldo; de los Santos, Berta; Arroyo, Francisco T.; Aguado-Puig, Ana; Romero, Fernando; Mercado, José-Ángel; Pliego-Alfaro, Fernando; Muñoz-Blanco, Juan; Caballero, José L.

    2016-01-01

    Understanding the nature of pathogen host interaction may help improve strawberry (Fragaria × ananassa) cultivars. Plant resistance to pathogenic agents usually operates through a complex network of defense mechanisms mediated by a diverse array of signaling molecules. In strawberry, resistance to a variety of pathogens has been reported to be mostly polygenic and quantitatively inherited, making it difficult to associate molecular markers with disease resistance genes. Colletotrichum acutatum spp. is a major strawberry pathogen, and completely resistant cultivars have not been reported. Moreover, strawberry defense network components and mechanisms remain largely unknown and poorly understood. Assessment of the strawberry response to C. acutatum included a global transcript analysis, and acidic hormones SA and JA measurements were analyzed after challenge with the pathogen. Induction of transcripts corresponding to the SA and JA signaling pathways and key genes controlling major steps within these defense pathways was detected. Accordingly, SA and JA accumulated in strawberry after infection. Contrastingly, induction of several important SA, JA, and oxidative stress-responsive defense genes, including FaPR1-1, FaLOX2, FaJAR1, FaPDF1, and FaGST1, was not detected, which suggests that specific branches in these defense pathways (those leading to FaPR1-2, FaPR2-1, FaPR2-2, FaAOS, FaPR5, and FaPR10) were activated. Our results reveal that specific aspects in SA and JA dependent signaling pathways are activated in strawberry upon interaction with C. acutatum. Certain described defense-associated transcripts related to these two known signaling pathways do not increase in abundance following infection. This finding suggests new insight into a specific putative molecular strategy for defense against this pathogen. PMID:27471515

  14. Partial Fractionation of Venoms from Two Iranian Vipers, Echis carinatus and Cerastes persicus Fieldi and Evaluation of Their Antiplatelet Activity.

    PubMed

    Mehdizadeh Kashani, Toktam; Vatanpour, Hossein; Zolfagharian, Hossein; Hooshdar Tehrani, Hasan; Heydari, Mohammad Hossein; Kobarfard, Farzad

    2012-01-01

    Platelet aggregation inhibitory effect and anticoagulant properties of fractions separated from the venoms of Cerastes persicus fieldi and Echis carinatus were investigated. The partial fractionation was performed on a Sephadex G-100 column. Two fractions separated from Cerastes persicus fieldi showed anti platelet aggregation activity on ADP (200 μM)-induced platelet aggregation (ca 80% inhibition). Attempts to measure the antiplatelet aggregation activity of crude Echis carinatus venom and its fractions were not successful due to the protein coagulation of the plasma samples after the addition of venom. Anticoagulant activities of venoms were also evaluated. Total venom of Echis carinatus showed anti coagulant activity in PT test, while its fractions showed procoagulant activity. PMID:24250552

  15. Partial Fractionation of Venoms from Two Iranian Vipers, Echis carinatus and Cerastes persicus Fieldi and Evaluation of Their Antiplatelet Activity

    PubMed Central

    Mehdizadeh Kashani, Toktam; Vatanpour, Hossein; Zolfagharian, Hossein; Hooshdar Tehrani, Hasan; Heydari, Mohammad Hossein; Kobarfard, Farzad

    2012-01-01

    Platelet aggregation inhibitory effect and anticoagulant properties of fractions separated from the venoms of Cerastes persicus fieldi and Echis carinatus were investigated. The partial fractionation was performed on a Sephadex G-100 column. Two fractions separated from Cerastes persicus fieldi showed anti platelet aggregation activity on ADP (200 μM)-induced platelet aggregation (ca 80% inhibition). Attempts to measure the antiplatelet aggregation activity of crude Echis carinatus venom and its fractions were not successful due to the protein coagulation of the plasma samples after the addition of venom. Anticoagulant activities of venoms were also evaluated. Total venom of Echis carinatus showed anti coagulant activity in PT test, while its fractions showed procoagulant activity. PMID:24250552

  16. Enhanced ammonia removal at room temperature by pH controlled partial nitrification and subsequent anaerobic ammonium oxidation.

    PubMed

    Durán, U; del Val Río, A; Campos, J L; Mosquera-Corral, A; Méndez, R

    2014-01-01

    The Anammox-based processes are suitable for the treatment of wastewaters characterized by a low carbon to nitrogen (C/N) ratio. The application of the Anammox process requires the availability of an effluent with a NO2- -N/NH4+ -N ratio composition around 1 g g-1, which involves the necessity of a previous step where the partial nitrification is performed. In this step, the inhibition of the nitrite-oxidizing bacteria (NOB) is crucial. In the present work, a combined partial nitrification-ANaerobic AMmonia OXidation (Anammox) two-units system operated at room temperature (20 degreeC) has been tested for the nitrogen removal of pre-treated pig slurry. To achieve the successful partial nitrification and inhibit the NOB activity, different ammonium/inorganic carbon (NH4+/IC) ratios were assayed from 1.19 to 0.82g NH4+-Ng-1 HCO3-C. This procedure provoked a decrease of the pH value to 6.0 to regulate the inhibitory effect over ammonia-oxidizing bacteria caused by free ammonia. Simultaneously, the NOB experienced the inhibitory effect of free nitrous acid which avoided the presence of nitrate in the effluent. The NH4+/IC ratio which allowed the obtaining of the desired effluent composition (50% of both ammonium and nitrite) was 0.82 +/- 0.02 g NH4+-N g-1 HCO3- -C. The Anammox reactor was fed with the effluent of the partial nitrification unit containing a NO2 -N/NH4+ -N ratio of 1 g g-1' where a nitrogen loading rate of 0.1 g N L-1 d-1 was efficiently removed. PMID:24600878

  17. Towards sub-optimal stochastic control of partially observable stochastic systems

    NASA Technical Reports Server (NTRS)

    Ruzicka, G. J.

    1980-01-01

    A class of multidimensional stochastic control problems with noisy data and bounded controls encountered in aerospace design is examined. The emphasis is on suboptimal design, the optimality being taken in quadratic mean sense. To that effect the problem is viewed as a stochastic version of the Lurie problem known from nonlinear control theory. The main result is a separation theorem (involving a nonlinear Kalman-like filter) suitable for Lurie-type approximations. The theorem allows for discontinuous characteristics. As a byproduct the existence of strong solutions to a class of non-Lipschitzian stochastic differential equations in dimensions is proven.

  18. Partial control of complex systems with application to the Fluidized Catalytic Cracker

    SciTech Connect

    Rinard, I.H.; Shinnar, R.

    1996-12-31

    The research deals with the control of complex nonlinear system with a limited number of manipulated variables. In many chemical processes the number of variables that make up the specifications and constraints exceeds the number of manipulated variables available. Furthermore, model information is limited. The goal of this work is to study the design of the control system and the conditions required to achieve adequate control for such cases. A Fluid Catalytic Cracker was chosen to illustrate and test the approach. This paper presents a short overview and summary of the approach and results.

  19. Active vibration control of civil structures

    SciTech Connect

    Farrar, C.; Baker, W.; Fales, J.; Shevitz, D.

    1996-11-01

    This is a final report of a one year, Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). Active vibration control (AVC) of structural and mechanical systems is one of the rapidly advancing areas of engineering research. The multifaceted nature of AVC covers many disciplines, such as sensors and instrumentation, numerical modeling, experimental mechanics, and advanced power systems. This work encompassed a review of the literature on active control of structures focusing both on active control hardware and on control algorithms, a design of an isolation systems using magneto-rheological fluid-filled (MRF) dampers and numerical simulations to study the enhanced vibration mitigation effects of this technology.

  20. Vector control activities: Fiscal Year, 1986

    SciTech Connect

    Not Available

    1987-04-01

    The program is divided into two major components - operations and support studies. The support studies are designed to improve the operational effectiveness and efficiency of the control program and to identify other vector control problems requiring TVA attention and study. Nonchemical methods of control are emphasized and are supplemented with chemical measures as needed. TVA also cooperates with various concerned municipalities in identifying blood-sucking arthropod pest problems and demonstrating control techniques useful in establishing abatement programs, and provides technical assistance to other TVA programs and organizations. The program also helps Land Between The Lakes (LBL) plan and conduct vector control operations and tick control research. Specific program control activities and support studies are discussed.

  1. Control with Partial Observations and an Explicit Solution of Mortensen's Equation

    SciTech Connect

    Benes, Vaclav E. Karatzas, Ioannis Ocone, Daniel Wang, Hui

    2004-05-15

    We formulate a stochastic control problem with a general information structure, and show that an optimal law exists and is characterized as the unique solution of a recursive stochastic equation. For a special information structure of the 'signal-plus-noise' type and with quadratic cost-functions, this recursive equation is solved for the value function of the control problem. This value function is then shown to satisfy the Mortensen equation of Dynamic Programming in function-space.

  2. Fluorimetric determination of the active form of tetracycline, chloretetracycline and oxytetracycline in partially decomposed solutions.

    PubMed

    Regosz, A

    1977-11-01

    The content of tetracycline (1), chlortetracycline (2) and oxytetracycline (3) has been determined by use of the fluorimetric method in partially decomposed acqueous solutions of different pH values. The procedure consisted in the extraction of fluorescent calcium and 5.5-diethyl-barbituric acid complexes of 1 and 3 (with 2 calcium complex only) into an organic solvent. In the method, only complexes with undecomposed 1--3 show a strong fluorescence. Products of decomposition of the antibiotics did not affect significantly analytical results. Comparative investigations have been carried out with 1--3 using t.l.c. and turbidimetry. PMID:24855

  3. CFD Modeling for Active Flow Control

    NASA Technical Reports Server (NTRS)

    Buning, Pieter G.

    2001-01-01

    This presentation describes current work under UEET Active Flow Control CFD Research Tool Development. The goal of this work is to develop computational tools for inlet active flow control design. This year s objectives were to perform CFD simulations of fully gridded vane vortex generators, micro-vortex genera- tors, and synthetic jets, and to compare flowfield results with wind tunnel tests of simple geometries with flow control devices. Comparisons are shown for a single micro-vortex generator on a flat plate, and for flow over an expansion ramp with sidewall effects. Vortex core location, pressure gradient and oil flow patterns are compared between experiment and computation. This work lays the groundwork for evaluating simplified modeling of arrays of devices, and provides the opportunity to test simple flow control device/sensor/ control loop interaction.

  4. Polyacetylenes from Notopterygium incisum–New Selective Partial Agonists of Peroxisome Proliferator-Activated Receptor-Gamma

    PubMed Central

    Liu, Xin; Noha, Stefan M.; Malainer, Clemens; Kramer, Matthias P.; Cocic, Amina; Kunert, Olaf; Schinkovitz, Andreas; Heiss, Elke H.; Schuster, Daniela

    2013-01-01

    Peroxisome proliferator-activated receptor gamma (PPARγ) is a key regulator of glucose and lipid metabolism and therefore an important pharmacological target to combat metabolic diseases. Since the currently used full PPARγ agonists display serious side effects, identification of novel ligands, particularly partial agonists, is highly relevant. Searching for new active compounds, we investigated extracts of the underground parts of Notopterygium incisum, a medicinal plant used in traditional Chinese medicine, and observed significant PPARγ activation using a PPARγ-driven luciferase reporter model. Activity-guided fractionation of the dichloromethane extract led to the isolation of six polyacetylenes, which displayed properties of selective partial PPARγ agonists in the luciferase reporter model. Since PPARγ activation by this class of compounds has so far not been reported, we have chosen the prototypical polyacetylene falcarindiol for further investigation. The effect of falcarindiol (10 µM) in the luciferase reporter model was blocked upon co-treatment with the PPARγ antagonist T0070907 (1 µM). Falcarindiol bound to the purified human PPARγ receptor with a Ki of 3.07 µM. In silico docking studies suggested a binding mode within the ligand binding site, where hydrogen bonds to Cys285 and Glu295 are predicted to be formed in addition to extensive hydrophobic interactions. Furthermore, falcarindiol further induced 3T3-L1 preadipocyte differentiation and enhanced the insulin-induced glucose uptake in differentiated 3T3-L1 adipocytes confirming effectiveness in cell models with endogenous PPARγ expression. In conclusion, we identified falcarindiol-type polyacetylenes as a novel class of natural partial PPARγ agonists, having potential to be further explored as pharmaceutical leads or dietary supplements. PMID:23630612

  5. Active control of robot manipulator compliance

    NASA Technical Reports Server (NTRS)

    Nguyen, C. C.; Pooran, F. J.

    1986-01-01

    Work performed at Catholic University on the research grant entitled Active Control of Robot Manipulator Compliance, supported by NASA/Goddard space Flight Center during the period of May 15th, 1986 to November 15th, 1986 is described. The modelling of the two-degree-of-freedom robot is first presented. Then the complete system including the robot and the hybrid controller is simulated on an IBM-XT Personal Computer. Simulation results showed that proper adjustments of controller gains enable the robot to perform successful operations. Further research should focus on developing a guideline for the controller gain design to achieve system stability.

  6. Optimal control techniques for active noise suppression

    NASA Technical Reports Server (NTRS)

    Banks, H. T.; Keeling, S. L.; Silcox, R. J.

    1988-01-01

    Active suppression of noise in a bounded enclosure is considered within the framework of optimal control theory. A sinusoidal pressure field due to exterior offending noise sources is assumed to be known in a neighborhood of interior sensors. The pressure field due to interior controlling sources is assumed to be governed by a nonhomogeneous wave equation within the enclosure and by a special boundary condition designed to accommodate frequency-dependent reflection properties of the enclosure boundary. The form of the controlling sources is determined by considering the steady-state behavior of the system, and it is established that the control strategy proposed is stable and asymptotically optimal.

  7. Simple relations for different stomatal control mechanisms link partially drying soil and transpiration

    NASA Astrophysics Data System (ADS)

    Huber, Katrin; Vanderborght, Jan; Javaux, Mathieu; Vereecken, Harry

    2015-04-01

    Stomata can close to regulate plant water loss under unfavourable water availability. This closure can be triggered by hydraulic ('H') and/or chemical signals ('C', 'H+C'). By combining plant hydraulic relations with a model for stomatal conductance, including chemical signalling, our aim was to derive a simple relation that links soil water availability, expressed as the fraction of roots in dry soil, to transpiration. We used the detailed mechanistic soil-root water flow model R-SWMS to verify this relation. Virtual split root experiments were simulated, comparing horizontally and vertically split domains with varying fractions of roots in dry soil and comparing different strengths of stomatal regulation by chemical and hydraulic signals. Transpiration predicted by the relation was in good agreement with numerical simulations. Under certain conditions H+C control leads to isohydric plant behaviour, which means that stomata close to keep leaf water potential constant after reaching a certain level. C control on the other hand exerts anisohydric behaviour, meaning that stomata remain fully open during changes in leaf water potential. For C control the relation between transpiration reduction and fraction of roots in dry soil becomes independent of transpiration rate whereas H+C control results in stronger reduction for higher transpiration rates. Simple relations that link effective soil and leaf water potential can describe different stomatal control resulting in contrasting behaviour.

  8. Active control of buckling of flexible beams

    NASA Technical Reports Server (NTRS)

    Baz, A.; Tampe, L.

    1989-01-01

    The feasibility of using the rapidly growing technology of the shape memory alloys actuators in actively controlling the buckling of large flexible structures is investigated. The need for such buckling control systems is becoming inevitable as the design trends of large space structures have resulted in the use of structural members that are long, slender, and very flexible. In addition, as these truss members are subjected mainly to longitudinal loading they become susceptible to structural instabilities due to buckling. Proper control of such instabilities is essential to the effective performance of the structures as stable platforms for communication and observation. Mathematical models are presented that simulate the dynamic characteristics of the shape memory actuator, the compressive structural members, and the associated active control system. A closed-loop computer-controlled system is designed, based on the developed mathematical models, and implemented to control the buckling of simple beams. The performance of the computer-controlled system is evaluated experimentally and compared with the theoretical predictions to validate the developed models. The obtained results emphasize the importance of buckling control and suggest the potential of the shape memory actuators as attractive means for controlling structural deformation in a simple and reliable way.

  9. Thermoeconomic optimal sizing for ice storage system in partial storage control strategies

    SciTech Connect

    Lee, K.H.; Joo, Y.J.; Choi, B.Y.; Kwon, S.C.

    1999-07-01

    This paper describes optimal sizing of ice storage and chiller system through parametric simulation for a commercial office building with peak cooling load of 600 tons. As an optimality criterion, the minimization of the annualized capital cost and fuel exergy costs on the basis of thermoeconomic analysis was chosen. This paper considers encapsulated ice storage system in chiller-downstream arrangement with chiller-priority control and storage-priority control strategies. Minimal required chiller sizes of the system for each control strategy are determined with storage fraction from 40% to 60%. The design condition, which has minimum cost, lies on the curve of the set of required chiller size and storage fraction. The optimal sizing is defined in this paper as the choice of size of chiller and storage tank, which leads to minimization of the annualized cost per exergy unit of product for the system.

  10. Rotor Flapping Response to Active Control

    NASA Technical Reports Server (NTRS)

    Nguyen, Khanh; Johnson, Wayne

    2004-01-01

    Rotor active control using higher harmonic blade pitch has been proposed as a means to reduce both rotor radiated noise and airframe vibration and to enhance rotor performance. The higher harmonic input, however, can affect rotor thrust and cyclic flapping - the basic trim characteristics of the rotor. Some of the trim changes can negate the active control benefits. For example, wind tunnel test results of a full scale BO-105 rotor with individual-blade control indicate some rotor performance improvements, accompanied with changes in rotor trim, using two-per-rev blade pitch input. The observed performance benefits could therefore be a simple manifestation of the trim change rather than an efficient redistribution of the rotor airloads. More recently, the flight test of the BO-105 helicopter equip,ped with individual-blade-control actuators also reported trim changes whenever the two-per-rev blade pitch for noise reduction was activated. The pilot had to adjust the trim control to maintain the aircraft under a constant flight path. These two cases highlight the, importance of trim considerations in the application of active control to rotorcraft.

  11. Actively controlled shaft seals for aerospace applications

    NASA Technical Reports Server (NTRS)

    Salant, Richard F.

    1994-01-01

    This study experimentally investigates an actively controlled mechanical seal for aerospace applications. The seal of interest is a gas seal, which is considerably more compact than previous actively controlled mechanical seals that were developed for industrial use. In a mechanical seal, the radial convergence of the seal interface has a primary effect on the film thickness. Active control of the film thickness is established by controlling the radial convergence of the seal interface with piezoelectric actuator. An actively controlled mechanical seal was initially designed and evaluated using a mathematical model. Based on these results, a seal was fabricated and tested under laboratory conditions. The seal was tested with both helium and air, at rotational speeds up to 3770 rad/sec, and at sealed pressures as high as 1.48 x 10(exp 6) Pa. The seal was operated with both manual control and with a closed-loop control system that used either the leakage rate or face temperature as the feedback. The output of the controller was the voltage applied to the piezoelectric actuator. The seal operated successfully for both short term tests (less than one hour) and for longer term tests (four hours) with a closed-loop control system. The leakage rates were typically 5-15 slm (standard liters per minute), and the face temperatures were generally maintained below 100 C. When leakage rate was used as the feedback signal, the setpoint leakage rate was typically maintained within 1 slm. However, larger deviations occurred during sudden changes in sealed pressure. When face temperature was used as the feedback signal, the setpoint face temperature was generally maintained within 3 C, with larger deviations occurring when the sealed pressure changed suddenly.

  12. Vector control activities. Fiscal year, 1982

    SciTech Connect

    Pickard, E.; Cooney, J.C.; McDuff, B.R.

    1983-06-01

    The goal of the TVA Vector Control Program is to protect the public from potential vectors of disease by controlling medically-important arthropod pests that are propagated on TVA lands or waters. In addition, freedom from annoying mosquitoes and other blood-sucking pests permits the development, use, and full enjoyment of the vast recreational opportunities offered by the many miles of freshwater lakes. To attain this goal the program is divided into operations and support studies. The support studies are designed to improve the operational effectiveness and efficiency of the control program and to identify other vector control problems that require TVA attention and study. Specifically, activities concerning water level management of TVA lakes, dewatering projects, plant growth control, drainage and insect control programs are detailed. Further, report is made of post-impoundment surveys, soil sampling studies of Mosquite larvae and ecological mosquito management studies.

  13. Actively Controlling Buffet-Induced Excitations

    NASA Technical Reports Server (NTRS)

    Moses, Robert W.; Pototzky, Anthony S.; Henderson, Douglas A.; Galea, Stephen C.; Manokaran, Donald S.; Zimcik, David G.; Wickramasinghe, Viresh; Pitt, Dale M.; Gamble, Michael A.

    2005-01-01

    High performance aircraft, especially those with twin vertical tails, encounter unsteady buffet loads when flying at high angles of attack. These loads result in significant random stresses, which may cause fatigue damage leading to restricted capabilities and availability of the aircraft. An international collaborative research activity among Australia, Canada and the United States, conducted under the auspices of The Technical Cooperation Program (TTCP) contributed resources toward a program that coalesced a broad range of technical knowledge and expertise into a single investigation to demonstrate the enhanced performance and capability of the advanced active BLA control system in preparation for a flight test demonstration. The research team investigated the use of active structural control to alleviate the damaging structural response to these loads by applying advanced directional piezoelectric actuators, the aircraft rudder, switch mode amplifiers, and advanced control strategies on an F/A-18 aircraft empennage. Some results of the full-scale investigation are presented herein.

  14. Rolling Maneuver Load Alleviation using active controls

    NASA Technical Reports Server (NTRS)

    Woods-Vedeler, Jessica A.; Pototzky, Anthony S.

    1992-01-01

    Rolling Maneuver Load Alleviation (RMLA) has been demonstrated on the Active Flexible Wing (AFW) wind tunnel model in the NASA Langley Transonic Dynamics Tunnel. The design objective was to develop a systematic approach for developing active control laws to alleviate wing incremental loads during roll maneuvers. Using linear load models for the AFW wind-tunnel model which were based on experimental measurements, two RMLA control laws were developed based on a single-degree-of-freedom roll model. The RMLA control laws utilized actuation of outboard control surface pairs to counteract incremental loads generated during rolling maneuvers and actuation of the trailing edge inboard control surface pairs to maintain roll performance. To evaluate the RMLA control laws, roll maneuvers were performed in the wind tunnel at dynamic pressures of 150, 200, and 250 psf and Mach numbers of 0.33, .38 and .44, respectively. Loads obtained during these maneuvers were compared to baseline maneuver loads. For both RMLA controllers, the incremental torsion moments were reduced by up to 60 percent at all dynamic pressures and performance times. Results for bending moment load reductions during roll maneuvers varied. In addition, in a multiple function test, RMLA and flutter suppression system control laws were operated simultaneously during roll maneuvers at dynamic pressures 11 percent above the open-loop flutter dynamic pressure.

  15. Feedback controllers for broadband active noise reduction

    NASA Astrophysics Data System (ADS)

    Petitjean, Benoit; Legrain, Isabelle

    1994-09-01

    The aim of the present paper is to demonstrate the efficiency of an LQG-based controller for the active control of the acoustic field radiated by a rectangular panel. This topic has been of interest for numerous researchers in the past 10 or 15 years, but very little attention has been paid to broadband disturbances occurring in a relatively high frequency range. These are unfortunately common features of noise perturbations in realistic structures such as airplanes or helicopters. The few articles that deal with this problem provide very scarce experimental results and are related to frequency bands where the structure dynamics is rather poor. From the outset, the problem at hand involves numerous difficulties, such as the modeling of the active structure itself and the possible large size of the controller. In the following, the experimental setup is described, then the controller design procedure is developed and finally some experimental results are shown that prove the efficiency of the method.

  16. Active Flow Control Stator With Coanda Surface

    NASA Technical Reports Server (NTRS)

    Guendogdu; Vorreiter; Seume

    2010-01-01

    Active Flow Control increases the permissible aerodynamic loading. Curved surface near the trailing edge ("Coanda surface"): a) increases turning -> higher pressure ratio. b) controls boundary layer separation -> increased surge margin. Objective: Reduce the number of vanes or compressor stages. Constraints: 1. In a real compressor, the vane must still function entirely without blowing. 2. Maintain the flow exit angle of the reference stator despite the resulting increase in stator loading.

  17. Active Vibration Control For Lasers And Spacecraft

    NASA Astrophysics Data System (ADS)

    Pearson, Jerome

    1983-12-01

    The Active Control of Space Structures (ACOSS) program of the Defense Advanced Research Projects Agency has identified problems in active vibration control of structural modes in extremely flexible space structures and in precisely pointed optics. The Air Force Wright Aeronautical Laboratories programs are an outgrowth of the ACOSS program. They are aimed at the problems of sensors, actuators, and their dynamic interactions with the structure to be controlled, and at the problem of system identification by one-g laboratory experiments. The VCOSS-1 and VCOSS-2 programs (Vibration Control of Space Structures) address the dynamic interactions of the sensor-actuator-structure; the Benchless Laser program and the Airborne Laser Mirror-Control program address the active control of HEL mirrors; the Experimental Modal Analysis and Component Synthesis and the Large Space Structure Dynamics programs address the problems of system identification and testing. Closer coordination with NASA and DARPA is being sought in support of on-orbit dynamic testing using the Space Shuttle and in the development of a national facility for one-g dynamics testing of large space structures.

  18. Active disturbance rejection controller for chemical reactor

    SciTech Connect

    Both, Roxana; Dulf, Eva H.; Muresan, Cristina I.

    2015-03-10

    In the petrochemical industry, the synthesis of 2 ethyl-hexanol-oxo-alcohols (plasticizers alcohol) is of high importance, being achieved through hydrogenation of 2 ethyl-hexenal inside catalytic trickle bed three-phase reactors. For this type of processes the use of advanced control strategies is suitable due to their nonlinear behavior and extreme sensitivity to load changes and other disturbances. Due to the complexity of the mathematical model an approach was to use a simple linear model of the process in combination with an advanced control algorithm which takes into account the model uncertainties, the disturbances and command signal limitations like robust control. However the resulting controller is complex, involving cost effective hardware. This paper proposes a simple integer-order control scheme using a linear model of the process, based on active disturbance rejection method. By treating the model dynamics as a common disturbance and actively rejecting it, active disturbance rejection control (ADRC) can achieve the desired response. Simulation results are provided to demonstrate the effectiveness of the proposed method.

  19. Active Control of Cryogenic Propellants in Space

    NASA Technical Reports Server (NTRS)

    Notardonato, William

    2011-01-01

    A new era of space exploration is being planned. Exploration architectures under consideration require the long term storage of cryogenic propellants in space. This requires development of active control systems to mitigate the effect of heat leak. This work summarizes current state of the art, proposes operational design strategies and presents options for future architectures. Scaling and integration of active systems will be estimated. Ideal long range spacecraft systems will be proposed with Exploration architecture benefits considered.

  20. Seismic active control by neural networks.

    SciTech Connect

    Tang, Y.

    1998-01-01

    A study on the application of artificial neural networks (ANNs) to activate structural control under seismic loads is carried out. The structure considered is a single-degree-of-freedom (SDF) system with an active bracing device. The control force is computed by a trained neural network. The feed-forward neural network architecture and an adaptive back-propagation training algorithm is used in the study. The neural net is trained to reproduce the function that represents the response-excitation relationship of the SDF system under seismic loads. The input-output training patterns are generated randomly. In the back-propagation training algorithm, the learning rate is determined by ensuring the decrease of the error function at each epoch. The computer program implemented is validated by solving the classification of the XOR problem. Then, the trained ANN is used to compute the control force according to the control strategy. If the control force exceeds the actuator's capacity limit, it is set equal to that limit. The concept of the control strategy employed herein is to apply the control force at every time step to cancel the system velocity induced at the preceding time step so that the gradual rhythmic buildup of the response is destroyed. The ground motions considered in the numerical example are the 1940 El Centro earthquake and the 1979 Imperial Valley earthquake in California. The system responses with and without the control are calculated and compared. The feasibility and potential of applying ANNs to seismic active control is asserted by the promising results obtained from the numerical examples studied.

  1. Seismic active control by neutral networks

    SciTech Connect

    Tang, Yu

    1995-12-31

    A study on the application of artificial neural networks (ANNs) to active structural control under seismic loads is carried out. The structure considered is a single-degree-of-freedom (SDF) system with an active bracing device. The control force is computed by a trained neural network. The feedforward neural network architecture and an adaptive backpropagation training algorithm is used in the study. The neural net is trained to reproduce the function that represents the response-excitation relationship of the SDF system under seismic loads. The input-output training patterns are generated randomly. In the backpropagation training algorithm, the learning rate is determined by ensuring the decrease of the error function at each epoch. The computer program implemented is validated by solving the classification of the XOR problem. Then, the trained ANN is used to compute the control force according to the control strategy. If the control force exceeds the actuator`s capacity limit, it is set equal to that limit. The concept of the control strategy employed herein is to apply the control force at every time step to cancel the system velocity induced at the preceding time step so that the gradual rhythmic buildup of the response is destroyed. The ground motions considered in the numerical example are the 1940 El Centro earthquake and the 1979 Imperial Valley earthquake in California. The system responses with and without the control are calculated and compared. The feasibility and potential of applying ANNs to seismic active control is asserted by the promising results obtained from the numerical examples studied.

  2. Active control: an investigation method for combustion instabilities

    NASA Astrophysics Data System (ADS)

    Poinsot, T.; Yip, B.; Veynante, D.; Trouvé, A.; Samaniego, J. M.; Candel, S.

    1992-07-01

    Closed-loop active control methods and their application to combustion instabilities are discussed. In these methods the instability development is impeded with a feedback control loop: the signal provided by a sensor monitoring the flame or pressure oscillations is processed and sent back to actuators mounted on the combustor or on the feeding system. Different active control systems tested on a non-premixed multiple-flame turbulent combustor are described. These systems can suppress all unstable plane modes of oscillation (i.e. low frequency modes). The active instability control (AIC) also constitutes an original and powerful technique for studies of mechanisms leading to instability or resulting from the instability. Two basic applications of this kind are described. In the first case the flame is initially controlled with AIC, the feedback loop is then switched off and the growth of the instability is analysed through high speed Schlieren cinematography and simultaneous sound pressure and reaction rate measurements. Three phases are identified during th growth of the oscillations: (1) a linear phase where acoustic waves induce a flapping motion of the flame sheets without interaction between sheets, (2) a modulation phase, where flame sheets interact randomly and (3) a nonlinear phase where the flame sheets are broken and a limit cycle is reached. In the second case we investigate different types of flame extinctions associated with combustion instability. It is shown that pressure oscillations may lead to partial or total extinctions. Extinctions occur in various forms but usually follow a rapid growth of pressure oscillations. The flame is extinguished during the modulation phase observed in the initiation experiments. In these studies devoted to transient instability phenomena, the control system constitutes a unique investigation tool because it is difficult to obtain the same information by other means. Implications for modelling and prediction of

  3. Precise and high-speed control of partial pressures of multiple gas species in plasma process chamber using pulse-controlled gas injection

    SciTech Connect

    Morishita, Sadaharu; Goto, Tetsuya; Nagase, Masaaki; Ohmi, Tadahiro

    2009-05-15

    Multiprocesses in a single plasma process chamber with high throughput require precise, sequential, high-speed alteration of partial pressures of multiple gas species. A conventional gas-distribution system cannot realize this because the system seriously overshoots gas pressure immediately following valve operation. Furthermore, chamber volume and conductance of gas piping between the system and chamber should both be considered because they delay the stabilizing time of gas pressure. Therefore, the authors proposed a new gas-distribution system without overshoot by controlling gas flow rate based on pressure measurement, as well as a method of pulse-controlled gas injection immediately following valve operation. Time variation of measured partial pressure agrees well with a calculation based on an equivalent-circuit model that represents the chamber and gas piping between the system and chamber. Using pulse-controlled gas injection, the stabilizing time can be reduced drastically to 0.6 s for HBr added to pure Ar plasma, and 0.7 s for O{sub 2} added to Ar/HBr plasma; without the pulse control, the stabilizing times are 3 and 7 s, respectively. In the O{sub 2} addition case, rapid stabilization can be achieved during the period of line/space pattern etching of poly-Si on a thin SiO{sub 2} film. This occurs without anomalous etching of the underlying SiO{sub 2} film or the Si substrate near the sidewall, thus obtaining a wide process margin with high throughput.

  4. Solubilization, partial purification, and reconstitution of glutamate- and N-methyl-D-aspartate-activated cation channels from brain synaptic membranes

    SciTech Connect

    Ly, A.M.; Michaelis, E.K. )

    1991-04-30

    L-Glutamate-activated cation channel proteins from rat brain synaptic membranes were solubilized, partially purified, and reconstituted into liposomes. Optimal conditions for solubilization and reconstitution included treatment of the membranes with nonionic detergents in the presence of neutral phospholipids plus glycerol. Quench-flow procedures were developed to characterize the rapid kinetics of ion flux induced by receptor agonists. ({sup 14}C)Methylamine, a cation that permeates through the open channel of both vertebrate and invertebrate glutamate receptors, was used to measure the activity of glutamate receptor-ion channel complexes in reconstituted liposomes. L-Glutamate caused an increase in the rate of ({sup 14}C)methylamine influx into liposomes reconstituted with either solubilized membrane proteins or partially purified glutamate-binding proteins. Of the major glutamate receptor agonists, only N-methyl-D-aspartate activated cation fluxes in liposomes reconstituted with glutamate-binding proteins. In liposomes reconstituted with glutamate-binding proteins, N-methyl-D-aspartate- or glutamate-induced influx of NA{sup +} led to a transient increase in the influx of the lipid-permeable anion probe S{sup 14}CN{sup {minus}}. These results indicate the functional reconstitution of N-methyl-D-aspartate-sensitive glutamate receptors and the role of the {approximately}69-kDa protein in the function of these ion channels.

  5. TORC1 activity is partially reduced under nitrogen starvation conditions in sake yeast Kyokai no. 7, Saccharomyces cerevisiae.

    PubMed

    Nakazawa, Nobushige; Sato, Aya; Hosaka, Masahiro

    2016-03-01

    Industrial yeasts are generally unable to sporulate but treatment with the immunosuppressive drug rapamycin restores this ability in a sake yeast strain Kyokai no. 7 (K7), Saccharomyces cerevisiae. This finding suggests that TORC1 is active under sporulation conditions. Here, using a reporter gene assay, Northern and Western blots, we tried to gain insight into how TORC1 function under nitrogen starvation conditions in K7 cells. Similarly to a laboratory strain, RPS26A transcription was repressed and Npr1 was dephosphorylated in K7 cells, indicative of the expected loss of TORC1 function under nitrogen starvation. The expression of nitrogen catabolite repression-sensitive genes, however, was not induced, the level of Cln3 remained constant, and autophagy was more slowly induced than in a laboratory strain, all suggestive of active TORC1. We conclude that TORC1 activity is partially reduced under nitrogen starvation conditions in K7 cells. PMID:26272416

  6. Stable performance of non‐aerated two‐stage partial nitritation/anammox (PANAM) with minimal process control

    PubMed Central

    Bagchi, Samik; Biswas, Rima; Vlaeminck, Siegfried E.; Roychoudhury, Kunal; Nandy, Tapas

    2012-01-01

    Summary Partial nitritation/anammox (PANAM) technologies have rapidly developed over the last decade, but still considerable amounts of energy are required for active aeration. In this study, a non‐aerated two‐stage PANAM process was investigated. In the first‐stage upflow fixed‐film bioreactor, nitratation could not be prevented at ammonium loading rates up to 186 mg N l−1 d−1 and low influent dissolved oxygen (0.1 mg O2 l−1). Yet, increasing the loading rate to 416 and 747 mg N l−1 d−1 by decreasing the hydraulic retention time to 8 and 5 h, respectively, resulted in partial nitritation with the desired nitrite to ammonium nitrogen ratio for the subsequent anammox stage (0.71–1.05). The second‐stage anammox reactor was established with a synthetic feeding based on ammonium and nitrite. After establishing anammox at low biomass content (0.5 g VSS l−1), the anammox influent was switched to partial nitritation effluent at a loading rate of 71 mg N l−1 d−1, of which 78% was removed at the stoichiometrically expected nitrite to ammonium consumption ratios (1.19) and nitrate production to ammonium consumption ratio (0.24). The combined PANAM reactors were operated for 3 months at a stable performance. Overall, PANAM appeals economically, saving about 50% of the energy costs, as well as technically, given straightforward operational principles. PMID:22414169

  7. Rolling maneuver load alleviation using active controls

    NASA Technical Reports Server (NTRS)

    Woods-Vedeler, Jessica A.; Pototzky, Anthony S.

    1992-01-01

    Rolling Maneuver Load Alleviation (RMLA) was demonstrated on the Active Flexible Wing (AFW) wind tunnel model in the LaRC Transonic Dynamics Tunnel. The design objective was to develop a systematic approach for developing active control laws to alleviate wing incremental loads during roll maneuvers. Using linear load models for the AFW wind-tunnel model which were based on experimental measurements, two RMLA control laws were developed based on a single-degree-of-freedom roll model. The RMLA control laws utilized actuation of outboard control surface pairs to counteract incremental loads generated during rolling maneuvers and roll performance. To evaluate the RMLA control laws, roll maneuvers were performed in the wind tunnel at dynamic pressures of 150, 200, and 250 psf and Mach numbers of .33, .38, and .44, respectively. Loads obtained during these maneuvers were compared to baseline maneuver loads. For both RMLA controllers, the incremental torsion moments were reduced by up to 60 percent at all dynamic pressures and performance times. Results for bending moment load reductions during roll maneuvers varied. In addition, in a multiple function test, RMLA and flutter suppression system control laws were operated simultaneously during roll maneuvers at dynamic pressures 11 percent above the open-loop flutter dynamic pressure.

  8. Dielectric elastomers for active vibration control applications

    NASA Astrophysics Data System (ADS)

    Herold, S.; Kaal, W.; Melz, T.

    2011-04-01

    Dielectric elastomers (DE) have proved to have high potential for smart actuator applications in many laboratory setups and also in first commercially available components. Because of their large deformation capability and the inherent fast response to external stimulation they proffer themselves to applications in the field of active vibration control, especially for lightweight structures. These structures typically tend to vibrate with large amplitudes even at low excitation forces. Here, DE actuators seem to be ideal components for setting up control loops to suppress unwanted vibrations. Due to the underlying physical effect DE actuators are generally non-linear elements with an approximately quadratic relationship between in- and output. Consequently, they automatically produce higher-order frequencies. This can cause harmful effects for vibration control on structures with high modal density. Therefore, a linearization technique is required to minimize parasitic effects. This paper shows and quantifies the nonlinearity of a commercial DE actuator and demonstrates the negative effects it can have in technical applications. For this purpose, two linearization methods are developed. Subsequently, the actuator is used to implement active vibration control for two different mechanical systems. In the first case a concentrated mass is driven with the controlled actuator resulting in a tunable oscillator. In the second case a more complex mechanical structure with multiple resonances is used. Different control approaches are applied likewise and their impact on the whole system is demonstrated. Thus, the potential of DE actuators for vibration control applications is highlighted.

  9. Piezoelectric Power Requirements for Active Vibration Control

    NASA Technical Reports Server (NTRS)

    Brennan, Matthew C.; McGowan, Anna-Maria Rivas

    1997-01-01

    This paper presents a method for predicting the power consumption of piezoelectric actuators utilized for active vibration control. Analytical developments and experimental tests show that the maximum power required to control a structure using surface-bonded piezoelectric actuators is independent of the dynamics between the piezoelectric actuator and the host structure. The results demonstrate that for a perfectly-controlled system, the power consumption is a function of the quantity and type of piezoelectric actuators and the voltage and frequency of the control law output signal. Furthermore, as control effectiveness decreases, the power consumption of the piezoelectric actuators decreases. In addition, experimental results revealed a non-linear behavior in the material properties of piezoelectric actuators. The material non- linearity displayed a significant increase in capacitance with an increase in excitation voltage. Tests show that if the non-linearity of the capacitance was accounted for, a conservative estimate of the power can easily be determined.

  10. A Dynamic Absorber With Active Vibration Control

    NASA Astrophysics Data System (ADS)

    Huang, S.-J.; Lian, R.-J.

    1994-12-01

    The design and construction of a dynamic absorber incorporating active vibration control is described. The absorber is a two-degrees-of-freedom spring — lumped mass system sliding on a guide pillar, with two internal vibration disturbance sources. Both the main mass and the secondary absorber mass are acted on by DC servo motors, respectively, to suppress the vibration amplitude. The state variable technique is used to model this dynamic system and a decoupling PID control method is used. First, the discrete time state space model is identified by using the commercial software MATLAB. Then the decoupling controller of this multi-input/multi-output system is derived from the identified model. Finally the results of some experiments are presented. The experimental results show that the system is effective in suppressing vibration. Also, the performance of this control strategy for position tracking control is evaluated based on experimental data.

  11. Neural predictive control for active buffet alleviation

    NASA Astrophysics Data System (ADS)

    Pado, Lawrence E.; Lichtenwalner, Peter F.; Liguore, Salvatore L.; Drouin, Donald

    1998-06-01

    The adaptive neural control of aeroelastic response (ANCAR) and the affordable loads and dynamics independent research and development (IRAD) programs at the Boeing Company jointly examined using neural network based active control technology for alleviating undesirable vibration and aeroelastic response in a scale model aircraft vertical tail. The potential benefits of adaptive control includes reducing aeroelastic response associated with buffet and atmospheric turbulence, increasing flutter margins, and reducing response associated with nonlinear phenomenon like limit cycle oscillations. By reducing vibration levels and thus loads, aircraft structures can have lower acquisition cost, reduced maintenance, and extended lifetimes. Wind tunnel tests were undertaken on a rigid 15% scale aircraft in Boeing's mini-speed wind tunnel, which is used for testing at very low air speeds up to 80 mph. The model included a dynamically scaled flexible fail consisting of an aluminum spar with balsa wood cross sections with a hydraulically powered rudder. Neural predictive control was used to actuate the vertical tail rudder in response to strain gauge feedback to alleviate buffeting effects. First mode RMS strain reduction of 50% was achieved. The neural predictive control system was developed and implemented by the Boeing Company to provide an intelligent, adaptive control architecture for smart structures applications with automated synthesis, self-optimization, real-time adaptation, nonlinear control, and fault tolerance capabilities. It is designed to solve complex control problems though a process of automated synthesis, eliminating costly control design and surpassing it in many instances by accounting for real world non-linearities.

  12. Actively Controlled Shaft Seals for Aerospace Applications

    NASA Technical Reports Server (NTRS)

    Salant, Richard F.; Wolff, Paul

    1995-01-01

    This study experimentally investigates an actively controlled mechanical seal for aerospace applications. The seal of interest is a gas seal, which is considerably more compact than previous actively controlled mechanical seals that were developed for industrial use. In a mechanical seal, the radial convergence of the seal interface has a primary effect on the film thickness. Active control of the film thickness is established by controlling the radial convergence of the seal interface with a piezoelectric actuator. An actively controlled mechanical seal was initially designed and evaluated using a mathematical model. Based on these results, a seal was fabricated and tested under laboratory conditions. The seal was tested with both helium and air, at rotational speeds up to 3770 rad/sec, and at sealed pressures as high as 1.48 x 10(exp 6) Pa. The seal was operated with both manual control and with a closed-loop control system that used either the leakage rate or face temperature as the feedback. The output of the controller was the voltage applied to the piezoelectric actuator. The seal operated successfully for both short term tests (less than one hour) and for longer term tests (four hours) with a closed-loop control system. The leakage rates were typically 5-15 slm (standard liters per minute), and the face temperatures were generally maintained below 100C. When leakage rate was used as the feedback signal, the setpoint leakage rate was typically maintained within 1 slm. However, larger deviations occurred during sudden changes in sealed pressure. When face temperature was used as the feedback signal, the setpoint face temperature was generally maintained within 3 C, with larger deviations occurring when the sealed pressure changes suddenly. the experimental results were compared to the predictions from the mathematical model. The model was successful in predicting the trends in leakage rate that occurred as the balance ratio and sealed pressure changed

  13. Review of levetiracetam, with a focus on the extended release formulation, as adjuvant therapy in controlling partial-onset seizures

    PubMed Central

    Ulloa, Carol M; Towfigh, Allen; Safdieh, Joseph

    2009-01-01

    Levetiracetam is a second-generation antiepileptic drug (AED) with a unique chemical structure and mechanism of action. The extended release formulation of levetiracetam (Keppra XR™; UCB Pharma) was recently approved by the Food and Drug Administration for adjunctive therapy in the treatment of partial-onset seizures in patients 16 years of age and older with epilepsy. This approval is based on a double-blind, randomized, placebo-controlled, multicenter, multinational trial. Levetiracetam XR allows for once-daily dosing, which may increase compliance and, given the relatively constant plasma concentrations, may minimize concentration-related adverse effects. Levetiracetam’s mode of action is not fully elucidated, but it has been found to target high-voltage, N-type calcium channels as well as the synaptic vesicle protein 2A (SV2A). Levetiracetam has nearly ideal pharmacokinetics. It is rapidly and almost completely absorbed after oral ingestion, is <10% protein-bound, demonstrates linear kinetics, is minimally metabolized through a pathway independent of the cytochrome P450 system, has no significant drug–drug interactions, and has a wide therapeutic index. The most common reported adverse events with levetiracetam XR were somnolence, irritability, dizziness, nausea, influenza, and nasopharyngitis. Levetiracetam XR provides an efficacious and well-tolerated treatment option for adjunctive therapy in the treatment of partial-onset seizures. PMID:19777068

  14. Dielectric elastomer actuators for active microfluidic control

    NASA Astrophysics Data System (ADS)

    McCoul, David; Murray, Coleman; Di Carlo, Dino; Pei, Qibing

    2013-04-01

    Dielectric elastomers with low modulus and large actuation strain have been investigated for applications in which they serve as "active" microfluidic channel walls. Anisotropically prestrained acrylic elastomer membranes are bonded to cover open trenches formed on a silicone elastomer substrate. Actuation of the elastomer membranes increases the cross-sectional area of the resulting channels, in turn controlling hydraulic flow rate and pressure. Bias voltage increases the active area of the membranes, allowing intrachannel pressure to alter channel geometry. The channels have also demonstrated the ability to actively clear a blockage. Applications may include adaptive microfilters, micro-peristaltic pumps, and reduced-complexity lab-on-a-chip devices.

  15. Cellular Mechanisms Controlling Caspase Activation and Function

    PubMed Central

    Parrish, Amanda B.; Freel, Christopher D.; Kornbluth, Sally

    2013-01-01

    Caspases are the primary drivers of apoptotic cell death, cleaving cellular proteins that are critical for dismantling the dying cell. Initially translated as inactive zymogenic precursors, caspases are activated in response to a variety of cell death stimuli. In addition to factors required for their direct activation (e.g., dimerizing adaptor proteins in the case of initiator caspases that lie at the apex of apoptotic signaling cascades), caspases are regulated by a variety of cellular factors in a myriad of physiological and pathological settings. For example, caspases may be modified posttranslationally (e.g., by phosphorylation or ubiquitylation) or through interaction of modulatory factors with either the zymogenic or active form of a caspase, altering its activation and/or activity. These regulatory events may inhibit or enhance enzymatic activity or may affect activity toward particular cellular substrates. Finally, there is emerging literature to suggest that caspases can participate in a variety of cellular processes unrelated to apoptotic cell death. In these settings, it is particularly important that caspases are maintained under stringent control to avoid inadvertent cell death. It is likely that continued examination of these processes will reveal new mechanisms of caspase regulation with implications well beyond control of apoptotic cell death. PMID:23732469

  16. Partially Key Distribution with Public Key Cryptosystem Based on Error Control Codes

    NASA Astrophysics Data System (ADS)

    Tavallaei, Saeed Ebadi; Falahati, Abolfazl

    Due to the low level of security in public key cryptosystems based on number theory, fundamental difficulties such as "key escrow" in Public Key Infrastructure (PKI) and a secure channel in ID-based cryptography, a new key distribution cryptosystem based on Error Control Codes (ECC) is proposed . This idea is done by some modification on McEliece cryptosystem. The security of ECC cryptosystem obtains from the NP-Completeness of block codes decoding. The capability of generating public keys with variable lengths which is suitable for different applications will be provided by using ECC. It seems that usage of these cryptosystems because of decreasing in the security of cryptosystems based on number theory and increasing the lengths of their keys would be unavoidable in future.

  17. MODELING MERCURY CONTROL WITH POWDERED ACTIVATED CARBON

    EPA Science Inventory

    The paper presents a mathematical model of total mercury removed from the flue gas at coal-fired plants equipped with powdered activated carbon (PAC) injection for Mercury control. The developed algorithms account for mercury removal by both existing equipment and an added PAC in...

  18. Spacecraft active thermal control technology status

    NASA Technical Reports Server (NTRS)

    Ellis, W. E.

    1978-01-01

    Four advanced space radiator concepts that were pursued in an integrated effort to develop multi-mission-use and low cost heat rejection systems which can overcome the limitations of current radiator systems are briefly discussed and described. Also, in order to establish a firm background to compare the advanced space radiator concepts, the Orbiter active thermal control system is also briefly described.

  19. DNA-based control of protein activity

    PubMed Central

    Engelen, W.; Janssen, B. M. G.

    2016-01-01

    DNA has emerged as a highly versatile construction material for nanometer-sized structures and sophisticated molecular machines and circuits. The successful application of nucleic acid based systems greatly relies on their ability to autonomously sense and act on their environment. In this feature article, the development of DNA-based strategies to dynamically control protein activity via oligonucleotide triggers is discussed. Depending on the desired application, protein activity can be controlled by directly conjugating them to an oligonucleotide handle, or expressing them as a fusion protein with DNA binding motifs. To control proteins without modifying them chemically or genetically, multivalent ligands and aptamers that reversibly inhibit their function provide valuable tools to regulate proteins in a noncovalent manner. The goal of this feature article is to give an overview of strategies developed to control protein activity via oligonucleotide-based triggers, as well as hurdles yet to be taken to obtain fully autonomous systems that interrogate, process and act on their environments by means of DNA-based protein control. PMID:26812623

  20. DNA-based control of protein activity.

    PubMed

    Engelen, W; Janssen, B M G; Merkx, M

    2016-03-01

    DNA has emerged as a highly versatile construction material for nanometer-sized structures and sophisticated molecular machines and circuits. The successful application of nucleic acid based systems greatly relies on their ability to autonomously sense and act on their environment. In this feature article, the development of DNA-based strategies to dynamically control protein activity via oligonucleotide triggers is discussed. Depending on the desired application, protein activity can be controlled by directly conjugating them to an oligonucleotide handle, or expressing them as a fusion protein with DNA binding motifs. To control proteins without modifying them chemically or genetically, multivalent ligands and aptamers that reversibly inhibit their function provide valuable tools to regulate proteins in a noncovalent manner. The goal of this feature article is to give an overview of strategies developed to control protein activity via oligonucleotide-based triggers, as well as hurdles yet to be taken to obtain fully autonomous systems that interrogate, process and act on their environments by means of DNA-based protein control. PMID:26812623

  1. Salivary gland extracts of partially fed Dermacentor reticulatus ticks decrease natural killer cell activity in vitro.

    PubMed Central

    Kubes, M; Fuchsberger, N; Labuda, M; Zuffová, E; Nuttall, P A

    1994-01-01

    The salivary glands and saliva of ticks (Arachnida, Acari, Ixodida) play a vital role in blood feeding, including manipulation of the host's immune response to tick infestation. Furthermore, a diverse number of tick-borne pathogens are transmitted to vertebrate hosts via tick saliva. A factor synthesized in the salivary glands of feeding ticks potentiates the transmission of certain tick-borne viruses. We show that salivary gland extracts (SGE) derived from Dermacentor reticulatus female ticks fed for 6 days on laboratory mice (SGED6) induced a decrease in the natural killer (NK) activity of effector cells obtained from 16 healthy blood donors. The decreased activity ranged from 14 to 69% of NK activity observed with the respective untreated effector cells. Such a decrease was not observed after treatment of effector cells with SGE from unfed ticks. Ten-fold dilution of SGED6 significantly reduced the capacity to decrease NK activity and a further 10-fold dilution almost eliminated the effect. After addition of IFN-alpha 2, the SGED6-induced decrease in NK activity was restored to activity levels approaching those of untreated cells. The apparent reversibility of the inhibition indicates that the effect of SGED6 on NK activity was not due to cytotoxicity. The results demonstrate the presence of a factor(s) in the salivary gland products of feeding D. reticulatus female ticks that influences human NK activity in vitro. These data suggest a possible mechanism by which tick SGE potentiates the transmission of some tick-borne viruses through suppression of NK activity. PMID:8045588

  2. Active control of vibration transmission through struts

    NASA Astrophysics Data System (ADS)

    Pelinescu, Ion; Balachandran, Balakumar

    1998-07-01

    In this work, analytical investigations into active control of longitudinal and flexural vibrations transmitted through a cylindrical strut are conducted. A mechanics based model for a strut fitted with a piezoelectric actuator is developed. For harmonic disturbances, a linear dynamic formulation describing the motion of the actuator is integrated with the formulation describing wave transmission through the strut, and the resulting system is studied in the frequency domain. Open-loop studies are conducted with the aid of numerical simulations, and the potential of active control schemes to attenuate the transmitted vibrations over the frequency range of 10 Hz to 6000 Hz is examined. The relevance of the current work to control of helicopter cabin interior noise is also discussed.

  3. Active control of transmitted sound in buildings

    NASA Astrophysics Data System (ADS)

    Thompsett, Russell Harvey George

    The problem of noise from neighbours has increased dramatically over the last few years. Many of the noise complaints are due to the high level, low frequency noise from modern stereo equipment, and are often described in terms of the low frequency characteristics of the music; the repetitive, booming, bass beat. The objective of this research was to establish the feasibility of applying active noise control to alleviate this problem. The initial approach was to evaluate the possibility of exploiting the dominance of individual modes in the response of rooms at low frequency to effect global control. However, initial investigations using a modal model of the sound field revealed that this would be difficult due to the contribution of many acoustic modes excited off resonance. This conclusion was supported by measurements of acoustic room responses in typical buildings, illustrating a non-resonant characteristic. Consequently, attention was turned to the feasibility of using local active control systems to create zones of quiet by concentrating control at a specific location near the observers ears, for example in a seat headrest, or near the pillows of a bed. The lack of a reference signal in either approach requires the use of a feedback control strategy. With a typically non-resonant system, the predictability in the disturbance necessary for successful feedback control must be contained in the primary excitation, namely the music. Examples of different music styles were investigated and of those with the potential to be a nuisance surprisingly few were significantly more predictable than a random disturbance. As expected the most encouraging control performance simulations were found for modern dance music, with a strong repetitive beat. A real-time, local controller was demonstrated in the laboratory with such a disturbance signal and the properties of the quiet zone were measured. The subjective response when hearing the controller in operation was found to be

  4. Stochastic optimal semi-active control of hysteretic systems by using a magneto-rheological damper

    NASA Astrophysics Data System (ADS)

    Cheng, H.; Zhu, W. Q.; Ying, Z. G.

    2006-06-01

    A stochastic optimal semi-active control strategy for stochastically excited hysteretic systems by using a magneto-rheological (MR) damper is proposed. The dynamics of both the hysteretic system and the MR damper is characterized by using the Bouc-Wen hysteretic model. The control force produced by the damper is split into a passive part and a semi-active part. The passive part is combined with the uncontrolled system to form a passively controlled system. Then the system is converted into an equivalent nonlinear non-hysteretic stochastic system, from which a partially averaged Itô stochastic differential equation is derived by using the stochastic averaging method of the energy envelope. For the ergodic control problem, a dynamical programming equation is established based on the stochastic dynamical programming principle and solved to yield the optimal semi-active control law. The fully averaged Itô equation is obtained by substituting the optimal semi-active control force into the partially averaged Itô equation and completing the averaging. Finally, the response of the semi-actively controlled system is obtained from solving the Fokker-Planck-Kolmogorov equation associated with the fully averaged Itô equation. The efficacy of the proposed control strategy is illustrated by the numerical results and comparison with clipped LQG control for an example.

  5. Detection and partial characterization of an inhibitor of plasminogen activator in human platelets.

    PubMed Central

    Erickson, L A; Ginsberg, M H; Loskutoff, D J

    1984-01-01

    In this study, we demonstrate the presence of a previously undescribed fibrinolytic inhibitor in human serum. It has an apparent molecular weight of 50,000 and is not detected in serum derived from platelet-poor plasma, suggesting that it originates from platelets. This conclusion is supported by a number of observations. For example, extracts of washed, gel-filtered human platelets contain an inhibitor of similar activity and size, and physiological concentrations of thrombin induce its release from the platelets. Moreover, the kinetics and dose dependency of this release are similar to those observed for the release of platelet factor 4, and the release of both molecules is blocked by pretreating the platelets with prostaglandin E1 and theophylline. Mixing experiments, which were devised to investigate the specificity of the inhibitor, showed that the fibrinolytic activity initiated by both urokinase and tissue-type plasminogen activator was blocked by platelet releasate in a dose-dependent manner. In both cases, the amount of inhibition increased when the releasates were preincubated with the purified activators, indicating a direct interaction between the activators and an inhibitor(s). The inhibitory activity was removed by preincubating the releasates with antiserum prepared against an antiactivator purified from cultured bovine aortic endothelial cells. These results indicate that platelets contain an inhibitor which is released by thrombin, inhibits both urokinase and tissue-type plasminogen activator, and is immunologically similar to an inhibitor produced by endothelial cells. This molecule may represent a new class of inhibitors, the antiactivators, which function together with alpha 2-antiplasmin to regulate the fibrinolytic system of the blood. Its release from platelets by thrombin may protect the growing thrombus against premature dissolution initiated by plasminogen activators released by the endothelium. Images PMID:6434594

  6. Growth of GaAs from a free surface melt under controlled arsenic pressure in a partially confined configuration

    NASA Technical Reports Server (NTRS)

    Gatos, H. C.; Lagowski, J.; Wu, Y.

    1988-01-01

    A partially confined configuration for the growth of GaAs from melt in space was developed, consisting of a triangular prism containing the seed crystal and source material in the form of a rod. It is suggested that the configuration overcomes two obstacles in the growth of GaAs in space: total confinement in a quartz crucible and lack of arsenic pressure control. Ground tests of the configuration show that it is capable of crystal growth in space and is useful for studying the growth of GaAs from a free-surface melt on earth. The resulting chemical composition, electrical property variations, and phenomenological models to account for the results are presented.

  7. Charge-controlled nano-structuring in partially collapsed star-shaped macromolecules.

    PubMed

    Uhlík, Filip; Košovan, Peter; Zhulina, Ekaterina B; Borisov, Oleg V

    2016-05-25

    Hydrophobic polyelectrolytes exhibit intra-molecular nano-scale self-organization instead of macroscopic phase separation because of the interplay between short-range hydrophobic attraction and long-range electrostatic repulsion. We aim to unravel how the morphology of the intra-molecular nanostructures can be controlled through the topology of the macromolecule on one hand and by adjustable ionization on the other hand. Specifically, we focus on hydrophobic star-branched polyelectrolytes, composed of either strong or weak acidic monomers. While both collapse in a globule when uncharged, and expand to full stretching of arms at high ionization, they exhibit quite different intermediate scenarios. For the strong ones, we observe the formation of bundles of arms as the main structural motif, and for the weak ones the intramolecular micelle-like structure is found at the same overall charge of the macromolecule. Here intramolecular disproportionation leaves some arms in a collapsed virtually neutral core, while others are substantially ionized and stretched in the corona. PMID:27140226

  8. Controlling Contagion Processes in Activity Driven Networks

    NASA Astrophysics Data System (ADS)

    Liu, Suyu; Perra, Nicola; Karsai, Márton; Vespignani, Alessandro

    2014-03-01

    The vast majority of strategies aimed at controlling contagion processes on networks consider the connectivity pattern of the system either quenched or annealed. However, in the real world, many networks are highly dynamical and evolve, in time, concurrently with the contagion process. Here, we derive an analytical framework for the study of control strategies specifically devised for a class of time-varying networks, namely activity-driven networks. We develop a block variable mean-field approach that allows the derivation of the equations describing the coevolution of the contagion process and the network dynamic. We derive the critical immunization threshold and assess the effectiveness of three different control strategies. Finally, we validate the theoretical picture by simulating numerically the spreading process and control strategies in both synthetic networks and a large-scale, real-world, mobile telephone call data set.

  9. Control Systems Cyber Security Standards Support Activities

    SciTech Connect

    Robert Evans

    2009-01-01

    The Department of Homeland Security’s Control Systems Security Program (CSSP) is working with industry to secure critical infrastructure sectors from cyber intrusions that could compromise control systems. This document describes CSSP’s current activities with industry organizations in developing cyber security standards for control systems. In addition, it summarizes the standards work being conducted by organizations within the sector and provides a brief listing of sector meetings and conferences that might be of interest for each sector. Control systems cyber security standards are part of a rapidly changing environment. The participation of CSSP in the development effort for these standards has provided consistency in the technical content of the standards while ensuring that information developed by CSSP is included.

  10. Actively controlled vibration welding system and method

    SciTech Connect

    Cai, Wayne W.; Kang, Bongsu; Tan, Chin-An

    2013-04-02

    A vibration welding system includes a controller, welding horn, an active material element, and anvil assembly. The assembly may include an anvil body connected to a back plate and support member. The element, e.g., a piezoelectric stack or shape memory alloy, is positioned with respect to the assembly. The horn vibrates in a desirable first direction to form a weld on a work piece. The element controls any vibrations in a second direction by applying calibrated response to the anvil body in the second direction. A method for controlling undesirable vibrations in the system includes positioning the element with respect to the anvil assembly, connecting the anvil body to the support member through the back plate, vibrating the horn in a desirable first direction, and transmitting an input signal to the element to control vibration in an undesirable second direction.

  11. Sulfated polysaccharides from Loligo vulgaris skin: potential biological activities and partial purification.

    PubMed

    Abdelmalek, Baha Eddine; Sila, Assaâd; Krichen, Fatma; Karoud, Wafa; Martinez-Alvarez, Oscar; Ellouz-Chaabouni, Semia; Ayadi, Mohamed Ali; Bougatef, Ali

    2015-01-01

    The characteristics, biological properties, and purification of sulfated polysaccharides extracted from squid (Loligo vulgaris) skin were investigated. Their chemical and physical characteristics were determined using X-ray diffraction and infrared spectroscopic analysis. Sulfated polysaccharides from squid skin (SPSS) contained 85.06% sugar, 2.54% protein, 1.87% ash, 8.07% sulfate, and 1.72% uronic acid. The antioxidant properties of SPSS were investigated based on DPPH radical-scavenging capacity (IC50 = 19.42 mg mL(-1)), hydrogen peroxide-scavenging activity (IC50 = 0.91 mg mL(-1)), and β-carotene bleaching inhibition (IC50 = 2.79 mg mL(-1)) assays. ACE-inhibitory activity of SPSS was also investigated (IC50 = 0.14 mg mL(-1)). Further antimicrobial activity assays indicated that SPSS exhibited marked inhibitory activity against the bacterial and fungal strains tested. Those polysaccharides did not display hemolytic activity towards bovine erythrocytes. Fractionation by DEAE-cellulose column chromatography showed three major absorbance peaks. Results of this study suggest that sulfated polysaccharides from squid skin are attractive sources of polysaccharides and promising candidates for future application as dietary ingredients. PMID:25301697

  12. Probiotic factors partially prevent changes to caspases 3 and 7 activation and transepithelial electrical resistance in a model of 5-fluorouracil-induced epithelial cell damage.

    PubMed

    Prisciandaro, Luca D; Geier, Mark S; Chua, Ann E; Butler, Ross N; Cummins, Adrian G; Sander, Guy R; Howarth, Gordon S

    2012-12-01

    The potential efficacy of a probiotic-based preventative strategy against intestinal mucositis has yet to be investigated in detail. We evaluated supernatants (SN) from Escherichia coli Nissle 1917 (EcN) and Lactobacillus rhamnosus GG (LGG) for their capacity to prevent 5-fluorouracil (5-FU)-induced damage to intestinal epithelial cells. A 5-day study was performed. IEC-6 cells were treated daily from days 0 to 3, with 1 mL of PBS (untreated control), de Man Rogosa Sharpe (MRS) broth, tryptone soy roth (TSB), LGG SN, or EcN SN. With the exception of the untreated control cells, all groups were treated with 5-FU (5 μM) for 24 h at day 3. Transepithelial electrical resistance (TEER) was determined on days 3, 4, and 5, while activation of caspases 3 and 7 was determined on days 4 and 5 to assess apoptosis. Pretreatment with LGG SN increased TEER (p < 0.05) compared to controls at day 3. 5-FU administration reduced TEER compared to untreated cells on days 4 and 5. Pretreatment with MRS, LGG SN, TSB, and EcN SN partially prevented the decrease in TEER induced by 5-FU on day 4, while EcN SN also improved TEER compared to its TSB vehicle control. These differences were also observed at day 5, along with significant improvements in TEER in cells treated with LGG and EcN SN compared to healthy controls. 5-FU increased caspase activity on days 4 and 5 compared to controls. At day 4, cells pretreated with MRS, TSB, LGG SN, or EcN SN all displayed reduced caspase activity compared to 5-FU controls, while both SN groups had significantly lower caspase activity than their respective vehicle controls. Caspase activity in cells pretreated with MRS, LGG SN, and EcN SN was also reduced at day 5, compared to 5-FU controls. We conclude that pretreatment with selected probiotic SN could prevent or inhibit enterocyte apoptosis and loss of intestinal barrier function induced by 5-FU, potentially forming the basis of a preventative treatment modality for mucositis. PMID:22526145

  13. Effect of short term external perturbations on bacterial ecology and activities in a partial nitritation and anammox reactor.

    PubMed

    Wu, Sha; Bhattacharjee, Ananda S; Weissbrodt, David G; Morgenroth, Eberhard; Goel, Ramesh

    2016-11-01

    This research investigated the short term effects of temperature changes (lasting 2-4weeks each) from 35±2°C to 21±2°C and 13±2°C and sulfide toxicity on partial nitrification-anammox (PN/A) system. Temperatures below 20°C and sulfide content as low as 5mgSL(-1) affected both aerobic and anaerobic catabolic activities of ammonia oxidation and the expression of related functional gene markers. The activity of AOB was inversely correlated with ammonium monooxygenase (amoA) gene expression. In contrast, the activity of AMX bacteria was positively correlated with the expression of their hydrazine synthase (hzsA) gene. Although the overall activities of AMX bacteria decreased at lower temperatures, the AMX bacteria were still active at the low temperatures. The inverse correlation between amoA gene expressions and the corresponding AOB activities was surprising. 16S rDNA based high throughput amplicon sequencing revealed the dominance of Chloroflexi, Planctomycetes and Proteobacteria phyla the distribution of which changed with temperature changes. PMID:27522119

  14. Evaluation of cytotoxic and anti-tumor activity of partially purified serine protease isolate from the Indian earthworm Pheretima posthuma

    PubMed Central

    Verma, Mahendra Kumar; Xavier, Francies; Verma, Yogendra Kumar; Sobha, Kota

    2013-01-01

    Objective To isolate, partially purify and evaluate the cytotoxic and antitumor activity of a serine protease from the chosen Indian earthworm Pheretima posthuma. Methods Whole animal extract was prepared and purified its protein constituents by size and charge based chromatographic separation techniques using Sephadex G-50 and DEAE-Cellulose resin respectively. Average molecular weight of the protein isolate was determined and analyzed for its cytotoxic property against Vero cells in different dilutions (1: 20 and 1: 40) and anti-tumor activity by MTT assay (a colorimetric assay) using breast cancer cell line MCF-7, with tamoxifen as standard. Results One of the protein constituents after purification was characterized as serine protease by Caseinolytic plate diffusion assay. Average molecular weight of this purified isolate was determined, by SDS-PAGE analysis with standard protein ladder, as of 15 kDa. The performed tests suggested that the 15kDa fraction has potent cytotoxic activity and satisfactory antitumor activity as well in vitro. Conclusions Exact molecular mechanism of the cytotoxic and antitumor activities is yet to be explored and currently we are working on ultra-purification and biophysical characterization of this fraction. Further investigation into the mechanism(s) of cytotoxic and antitumor activities at molecular level would be useful in treatment of various classes of cancer and viral infections in future.

  15. Optogenetic feedback control of neural activity

    PubMed Central

    Newman, Jonathan P; Fong, Ming-fai; Millard, Daniel C; Whitmire, Clarissa J; Stanley, Garrett B; Potter, Steve M

    2015-01-01

    Optogenetic techniques enable precise excitation and inhibition of firing in specified neuronal populations and artifact-free recording of firing activity. Several studies have suggested that optical stimulation provides the precision and dynamic range requisite for closed-loop neuronal control, but no approach yet permits feedback control of neuronal firing. Here we present the ‘optoclamp’, a feedback control technology that provides continuous, real-time adjustments of bidirectional optical stimulation in order to lock spiking activity at specified targets over timescales ranging from seconds to days. We demonstrate how this system can be used to decouple neuronal firing levels from ongoing changes in network excitability due to multi-hour periods of glutamatergic or GABAergic neurotransmission blockade in vitro as well as impinging vibrissal sensory drive in vivo. This technology enables continuous, precise optical control of firing in neuronal populations in order to disentangle causally related variables of circuit activation in a physiologically and ethologically relevant manner. DOI: http://dx.doi.org/10.7554/eLife.07192.001 PMID:26140329

  16. Limitation in tidal volume expansion partially determines the intensity of physical activity in COPD.

    PubMed

    Kortianou, Eleni A; Aliverti, Andrea; Louvaris, Zafeiris; Vasilopoulou, Maroula; Nasis, Ioannis; Asimakos, Andreas; Zakynthinos, Spyros; Vogiatzis, Ioannis

    2015-01-01

    In patients with chronic obstructive pulmonary disease (COPD), reduced levels of daily physical activity are associated with the degree of impairment in lung, peripheral muscle, and central hemodynamic function. There is, however, limited evidence as to whether limitations in tidal volume expansion also, importantly, determine daily physical activity levels in COPD. Eighteen consecutive patients with COPD [9 active (forced expiratory volume in 1 s, FEV1: 1.59 ± 0.64 l) with an average daily movement intensity >1.88 m/s(2) and 9 less active patients (FEV1: 1.16 ± 0.41 l) with an average intensity <1.88 m/s(2)] underwent a 4-min treadmill test at a constant speed corresponding to each individual patient's average movement intensity, captured by a triaxial accelerometer during a preceding 7-day period. When chest wall volumes, captured by optoelectronic plethysmography, were expressed relative to comparable levels of minute ventilation (ranging between 14.5 ± 4.3 to 33.5 ± 4.4 l/min), active patients differed from the less active ones in terms of the lower increase in end-expiratory chest wall volume (by 0.15 ± 0.17 vs. 0.45 ± 0.21 l), the greater expansion in tidal volume (by 1.76 ± 0.58 vs. 1.36 ± 0.24 l), and the larger inspiratory reserve chest wall volume (IRVcw: by 0.81 ± 0.25 vs. 0.39 ± 0.27 l). IRVcw (r(2) = 0.420), expiratory flow (r(2) change = 0.174), and Borg dyspnea score (r(2) change = 0.123) emerged as the best contributors, accounting for 71.7% of the explained variance in daily movement intensity. Patients with COPD exhibiting greater ability to expand tidal volume and to maintain adequate inspiratory reserve volume tend to be more physically active. Thus interventions aiming at mitigating restrictions on operational chest wall volumes are expected to enhance daily physical activity levels in COPD. PMID:25398190

  17. Vibrating surface actuators for active flow control

    NASA Astrophysics Data System (ADS)

    Calkins, Frederick T.; Clingman, Dan J.

    2002-07-01

    Current research has shown that aircraft can gain significant aerodynamic performance benefits from active flow control (AFC). AFC seeks to control large scale flows by exploiting natural response triggered by small energy inputs. The principal target application is download alleviation of the V-22 Osprey under the DARPA sponsored Boeing Active Flow Control System program. One method of injecting energy into the flow over the V22 wings is to use an active vibrating surface on the passive seal between the wing and flapperon. The active surface is an oscillating cantilevered beam which injects fluid into the flow, similar to a synthetic jet, and interacts with the flow field. Two types of actuators, or flipperons, are explored. The first is a multilayer piezoelectric polyvinylidene fluoride cantilevered bender. The second is a single crystal piezoelectric (SCP)d31 poled wafer mounted on a cantilevered spring steel substrate. This paper details the development effort including fabrication, mechanical and electrical testing, and modeling for both types of actuators. Both flipperons were mounted on the passive seal between a 1/10th scale V22 wing and flapperon and the aerodynamic performance evaluated in low speed wind tunnel. The SCP flipperon demonstrated significant cruise benefits, with increase of 10 percent lift and 20 percent angle of attack capability. The PVDF flipperon provided a 16 percent drag reduction in the hover mode.

  18. Market-based control of active surfaces

    NASA Astrophysics Data System (ADS)

    Berlin, Andrew A.; Hogg, Tad; Jackson, Warren B.

    1998-12-01

    This paper describes a market-based approach to controlling a smart matter-based object transport system, in which an array of distributed air jets applies forces to levitate and control the motion of a planar object. In the smart matter regime, the effects of spatial and temporal variation of operating parameters among a multiplicity of sensor, actuators, and controllers make it desirable for a control strategy to exhibit a minimal dependence on system models, and to be able to arbitrate among conflicting goals. A market-based strategy is introduced that aggregates the control requirements of multiple relatively simple local controllers, each of which seeks to optimize the performance of the system within a limited spatial and temporal range. These local controllers act as the market's consumers, and two sets of distributed air jets act as the producers. Experiments are performed comparing the performance of the market-based strategy to a near-optimal model-derived benchmark, as well as to a hand-tuned PD controller. Results indicate that even though the local controllers in the market are not based on a detailed model of the system dynamics, the market is able to effectively approximate the performance of the model-based benchmark. In certain specialized cases, such as tracking a step trajectory, the performance of the market surpasses the performance of the model-based benchmark by balancing the needs of conflicting control goals. A brief overview of the active surface smart matter prototype being developed at Xerox PARC that is the motivation behind this work is also presented.

  19. Sustained Oxidative Stress Inhibits NF-kB Activation Partially via Inactivating the Proteasome

    Technology Transfer Automated Retrieval System (TEKTRAN)

    NF-kB is a family of important transcription factors involved in many cellular functions, such as cell survival, proliferation and stress responses. Many studies indicate that NF-kB is a stress sensitive transcription factor and its activation is regulated by reactive oxygen species. In previous s...

  20. Antifatigue Activity of Liquid Cultured Tricholoma matsutake Mycelium Partially via Regulation of Antioxidant Pathway in Mouse

    PubMed Central

    Li, Quan; Wang, Yanzhen; Cai, Guangsheng; Kong, Fange; Wang, Xiaohan; Liu, Yang; Yang, Chuanbin; Wang, Di; Teng, Lirong

    2015-01-01

    Tricholoma matsutake has been popular as food and biopharmaceutical materials in Asian countries for its various pharmacological activities. The present study aims to analyze the antifatigue effects on enhancing exercise performance of Tricholoma matsutake fruit body (ABM) and liquid cultured mycelia (TM) in mouse model. Two-week Tricholoma matsutake treatment significantly enhances the exercise performance in weight-loaded swimming, rotating rod, and forced running test. In TM- and ABM-treated mice, some factors were observed at 60 min after swimming compared with nontreated mice, such as the increased levels of adenosine triphosphate (ATP), antioxidative enzymes, and glycogen and the reduced levels of malondialdehyde and reactive oxygen species in muscle, liver, and/or serum. Further data obtained from western blot show that CM and ABM have strongly enhanced the activation of 5′-AMP-activated protein kinase (AMPK), and the expressions of peroxisome proliferator have activated receptor γ coactivator-1α (PGC-1α) and phosphofructokinase-1 (PFK-1) in liver. Our data suggest that both Tricholoma matsutake fruit body and liquid cultured mycelia possess antifatigue effects related to AMPK-linked antioxidative pathway. The information uncovered in our study may serve as a valuable resource for further identification and provide experimental evidence for clinical trials of Tricholoma matsutake as an effective agent against fatigue related diseases. PMID:26697489

  1. 75 FR 70208 - Certain Activated Carbon From the People's Republic of China: Final Results and Partial...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-11-17

    ... Second Antidumping Duty Administrative Review, and Preliminary Rescission in Part, 75 FR 26927 (May 13... review was requested. See Initiation of Antidumping and Countervailing Duty Administrative Reviews, 74 FR... Administrative Review, 74 FR 31690 (July 2, 2009). \\3\\ See Certain Activated Carbon From the People's Republic...

  2. Hybrid dampers for active vibration control

    SciTech Connect

    Gordaninejad, F.; Ray, A.

    1994-12-31

    In the present investigation feasibility of using hybrid electrorheological (ER) fluid dampers for active vibration control is examined. Small-scale, three-electrode hybrid dampers were designed and built such that they have two separate compartments to contain a viscous oil and an ER fluid. The results were compared to those obtained using a three-electrode ER fluid damper. It was shown that the use of hybrid ER fluid damper can enhance the damping. It was also found that the bang-bang and linear proportional control algorithms have similar effects on the amplitude-time response obtained from hybrid and ER fluid dampers.

  3. Distributed Energy Communications & Controls, Lab Activities - Summary

    SciTech Connect

    Rizy, D Tom

    2010-01-01

    The purpose is to develop controls for inverter-based renewable and non-renewable distributed energy systems to provide local voltage, power and power quality support for loads and the power grid. The objectives are to (1) develop adaptive controls for inverter-based distributed energy (DE) systems when there are multiple inverters on the same feeder and (2) determine the impact of high penetration high seasonal energy efficiency ratio (SEER) air conditioning (A/C) units on power systems during sub-transmission faults which can result in an A/C compressor motor stall and assess how inverter-based DE can help to mitigate the stall event. The Distributed Energy Communications & Controls Laboratory (DECC) is a unique facility for studying dynamic voltage, active power (P), non-active power (Q) and power factor control from inverter-based renewable distributed energy (DE) resources. Conventionally, inverter-based DE systems have been designed to provide constant, close to unity power factor and thus not provide any voltage support. The DECC Lab interfaces with the ORNL campus distribution system to provide actual power system testing of the controls approach. Using mathematical software tools and the DECC Lab environment, we are developing and testing local, autonomous and adaptive controls for local voltage control and P & Q control for inverter-based DE. We successfully tested our active and non-active power (P,Q) controls at the DECC laboratory along with voltage regulation controls. The new PQ control along with current limiter controls has been tested on our existing inverter test system. We have tested both non-adaptive and adaptive control modes for the PQ control. We have completed several technical papers on the approaches and results. Electric power distribution systems are experiencing outages due to a phenomenon known as fault induced delayed voltage recovery (FIDVR) due to air conditioning (A/C) compressor motor stall. Local voltage collapse from FIDVR is

  4. Partial in vitro analysis of toxic and antigenic activities of eleven Peruvian pitviper snake venoms.

    PubMed

    Guerra-Duarte, C; Lopes-Peixoto, J; Fonseca-de-Souza, B R; Stransky, S; Oliveira, D; Schneider, F S; Lopes-de-Souza, L; Bonilla, C; Silva, W; Tintaya, B; Yarleque, A; Chávez-Olórtegui, C

    2015-12-15

    This work used eleven Peruvian snake venoms (Bothrops andianus, Bothrops atrox, Bothrops barnetti, Bothrops castelnaudi, Bothriopsis chloromelas, Bothrocophias microphthalmus, Bothrops neuwiedi, Bothriopsis oligolepis, Bothriopsis peruviana, Bothrops pictus and Bothriopsis taeniata) to perform in vitro experimentation and determine its main characteristics. Hyaluronidase (HYAL), phospholipase A2 (PLA2), snake venom metalloproteinase (SVMP), snake venom serine protease (SVSP) and L-amino acid oxidase (LAAO) activities; toxicity by cell viability assays using MGSO3, VERO and HeLa cell lineages; and crossed immunoreactivity with Peruvian (PAV) and Brazilian (BAV) antibothropic polyvalent antivenoms, through ELISA and Western Blotting assays, were determined. Results show that the activities tested in this study were not similar amongst the venoms and each species present their own peculiarities, highlighting the diversity within Bothrops complex. All venoms were capable of reducing cell viability of all tested lineages. It was also demonstrated the crossed recognition of all tested venoms by both antivenoms. PMID:26365916

  5. Activity-dependent changes in partial VAMP complexes during neurotransmitter release.

    PubMed

    Hua, S Y; Charlton, M P

    1999-12-01

    The temporal sequence of SNARE protein interactions that cause exocytosis is unknown. Blockade of synaptic neurotransmitter release through cleavage of VAMP/synaptobrevin by tetanus toxin light chain (TeNT-LC) was accelerated by nerve stimulation. Botulinum/B neurotoxin light chain (BoNT/B-LC), which cleaves VAMP at the same site as TeNT-LC, did not require stimulation. Because TeNT-LC requires the N-terminal coil domain of VAMP for binding but BoNT/B-LC requires the C-terminal coil domain, it seems that, before nerve activity, the N-terminal domain is shielded in a protein complex, but the C-terminal domain is exposed. This N-terminal complex lasts until nerve activity occurs and may serve to cock synaptic vesicles for immediate exocytosis upon Ca2+ entry. PMID:10570484

  6. Linking mutagenic activity to micropollutant concentrations in wastewater samples by partial least square regression and subsequent identification of variables.

    PubMed

    Hug, Christine; Sievers, Moritz; Ottermanns, Richard; Hollert, Henner; Brack, Werner; Krauss, Martin

    2015-11-01

    We deployed multivariate regression to identify compounds co-varying with the mutagenic activity of complex environmental samples. Wastewater treatment plant (WWTP) effluents with a large share of industrial input of different sampling dates were evaluated for mutagenic activity by the Ames Fluctuation Test and chemically characterized by a screening for suspected pro-mutagens and non-targeted software-based peak detection in full scan data. Areas of automatically detected peaks were used as predictor matrix for partial least squares projections to latent structures (PLS) in combination with measured mutagenic activity. Detected peaks were successively reduced by the exclusion of all peaks with lowest variable importance until the best model (high R(2) and Q(2)) was reached. Peaks in the best model co-varying with the observed mutagenicity showed increased chlorine, bromine, sulfur, and nitrogen abundance compared to original peak set indicating a preferential selection of anthropogenic compounds. The PLS regression revealed four tentatively identified compounds, newly identified 4-(dimethylamino)-pyridine, and three known micropollutants present in domestic wastewater as co-varying with the mutagenic activity. Co-variance between compounds stemming from industrial wastewater and mutagenic activity supported the application of "virtual" EDA as a statistical tool to separate toxicologically relevant from less relevant compounds. PMID:26070082

  7. The effects of neuromuscular exercise on medial knee joint load post-arthroscopic partial medial meniscectomy: ‘SCOPEX’ a randomised control trial protocol

    PubMed Central

    2012-01-01

    Background Meniscectomy is a risk factor for knee osteoarthritis, with increased medial joint loading a likely contributor to the development and progression of knee osteoarthritis in this group. Therefore, post-surgical rehabilitation or interventions that reduce medial knee joint loading have the potential to reduce the risk of developing or progressing osteoarthritis. The primary purpose of this randomised, assessor-blind controlled trial is to determine the effects of a home-based, physiotherapist-supervised neuromuscular exercise program on medial knee joint load during functional tasks in people who have recently undergone a partial medial meniscectomy. Methods/design 62 people aged 30–50 years who have undergone an arthroscopic partial medial meniscectomy within the previous 3 to 12 months will be recruited and randomly assigned to a neuromuscular exercise or control group using concealed allocation. The neuromuscular exercise group will attend 8 supervised exercise sessions with a physiotherapist and will perform 6 exercises at home, at least 3 times per week for 12 weeks. The control group will not receive the neuromuscular training program. Blinded assessment will be performed at baseline and immediately following the 12-week intervention. The primary outcomes are change in the peak external knee adduction moment measured by 3-dimensional analysis during normal paced walking and one-leg rise. Secondary outcomes include the change in peak external knee adduction moment during fast pace walking and one-leg hop and change in the knee adduction moment impulse during walking, one-leg rise and one-leg hop, knee and hip muscle strength, electromyographic muscle activation patterns, objective measures of physical function, as well as self-reported measures of physical function and symptoms and additional biomechanical parameters. Discussion The findings from this trial will provide evidence regarding the effect of a home-based, physiotherapist

  8. Unsteady aerodynamic modeling and active aeroelastic control

    NASA Technical Reports Server (NTRS)

    Edwards, J. W.

    1977-01-01

    Unsteady aerodynamic modeling techniques are developed and applied to the study of active control of elastic vehicles. The problem of active control of a supercritical flutter mode poses a definite design goal stability, and is treated in detail. The transfer functions relating the arbitrary airfoil motions to the airloads are derived from the Laplace transforms of the linearized airload expressions for incompressible two dimensional flow. The transfer function relating the motions to the circulatory part of these loads is recognized as the Theodorsen function extended to complex values of reduced frequency, and is termed the generalized Theodorsen function. Inversion of the Laplace transforms yields exact transient airloads and airfoil motions. Exact root loci of aeroelastic modes are calculated, providing quantitative information regarding subcritical and supercritical flutter conditions.

  9. Treatment of CELSS and PCELSS waste to produce nutrients for plant growth. [Controlled Ecological Life Support Systems and Partially Controlled Ecological Life Support Systems

    NASA Technical Reports Server (NTRS)

    Modell, M.; Meissner, H.; Karel, M.; Carden, J.; Lewis, S.

    1981-01-01

    The research program entitled 'Development of a Prototype Experiment for Treating CELSS (Controlled Ecological Life Support Systems) and PCELSS (Partially Controlled Ecological Life Support Systems) Wastes to Produce Nutrients for Plant Growth' consists of two phases: (1) the development of the neccessary facilities, chemical methodologies and models for meaningful experimentation, and (2) the application of what methods and devices are developed to the interfacing of waste oxidation with plant growth. Homogeneous samples of freeze-dried human feces and urine have been prepared to ensure comparability of test results between CELSS waste treatment research groups. A model of PCELSS food processing wastes has been developed, and an automated gas chromatographic system to analyze oxidizer effluents was designed and brought to operational status. Attention is given the component configuration of the wet oxidation system used by the studies.

  10. Advanced Active Thermal Control Systems Architecture Study

    NASA Technical Reports Server (NTRS)

    Hanford, Anthony J.; Ewert, Michael K.

    1996-01-01

    The Johnson Space Center (JSC) initiated a dynamic study to determine possible improvements available through advanced technologies (not used on previous or current human vehicles), identify promising development initiatives for advanced active thermal control systems (ATCS's), and help prioritize funding and personnel distribution among many research projects by providing a common basis to compare several diverse technologies. Some technologies included were two-phase thermal control systems, light-weight radiators, phase-change thermal storage, rotary fluid coupler, and heat pumps. JSC designed the study to estimate potential benefits from these various proposed and under-development thermal control technologies for five possible human missions early in the next century. The study compared all the technologies to a baseline mission using mass as a basis. Each baseline mission assumed an internal thermal control system; an external thermal control system; and aluminum, flow-through radiators. Solar vapor compression heat pumps and light-weight radiators showed the greatest promise as general advanced thermal technologies which can be applied across a range of missions. This initial study identified several other promising ATCS technologies which offer mass savings and other savings compared to traditional thermal control systems. Because the study format compares various architectures with a commonly defined baseline, it is versatile and expandable, and is expected to be updated as needed.

  11. Instabilities in attractor networks with fast synaptic fluctuations and partial updating of the neurons activity.

    PubMed

    Torres, J J; Marro, J; Cortes, J M; Wemmenhove, B

    2008-11-01

    We present and study a probabilistic neural automaton in which the fraction of simultaneously-updated neurons is a parameter, rhoin(0,1). For small rho, there is relaxation towards one of the attractors and a great sensibility to external stimuli and, for rho > or = rho(c), itinerancy among attractors. Tuning rho in this regime, oscillations may abruptly change from regular to chaotic and vice versa, which allows one to control the efficiency of the searching process. We argue on the similarity of the model behavior with recent observations, and on the possible role of chaos in neurobiology. PMID:18701255

  12. Active Thermal Control System Development for Exploration

    NASA Technical Reports Server (NTRS)

    Westheimer, David

    2007-01-01

    All space vehicles or habitats require thermal management to maintain a safe and operational environment for both crew and hardware. Active Thermal Control Systems (ATCS) perform the functions of acquiring heat from both crew and hardware within a vehicle, transporting that heat throughout the vehicle, and finally rejecting that energy into space. Almost all of the energy used in a space vehicle eventually turns into heat, which must be rejected in order to maintain an energy balance and temperature control of the vehicle. For crewed vehicles, Active Thermal Control Systems are pumped fluid loops that are made up of components designed to perform these functions. NASA has been actively developing technologies that will enable future missions or will provide significant improvements over the state of the art technologies. These technologies have are targeted for application on the Crew Exploration Vehicle (CEV), or Orion, and a Lunar Surface Access Module (LSAM). The technologies that have been selected and are currently under development include: fluids that enable single loop ATCS architectures, a gravity insensitive vapor compression cycle heat pump, a sublimator with reduced sensitivity to feedwater contamination, an evaporative heat sink that can operate in multiple ambient pressure environments, a compact spray evaporator, and lightweight radiators that take advantage of carbon composites and advanced optical coatings.

  13. Study of a mechanism responsible for potential antidepressant activity of EMD 386088, a 5-HT6 partial agonist in rats.

    PubMed

    Jastrzębska-Więsek, Magdalena; Siwek, Agata; Partyka, Anna; Antkiewicz-Michaluk, Lucyna; Michaluk, Jerzy; Romańska, Irena; Kołaczkowski, Marcin; Wesołowska, Anna

    2016-08-01

    It was shown that 5-HT6 receptor agonists can exert pharmacological activity due to various modifications in monoamines' level and metabolism activity in rats' brain structures. This finding was correlated with antidepressant- or anxiolytic-like properties of these compounds. The study was designed to establish a possible mechanism of the antidepressant-like activity of the partial 5-HT6 receptor agonist EMD386088 (5-chloro-2-methyl-3-(1,2,3,6-tetrahydro-4-pyridinyl)-1H-indole hydrochloride) in rats. The concentrations of monoamines (dopamine (DA), noradrenaline (NA), and serotonin (5-HT)) and the rate of their metabolism were measured ex vivo in the brain structures (hippocampus, nucleus accumbens, striatum) using high-performance liquid chromatography (HPLC). The rats were killed after the forced swim test (FST); the collected tissue samples were used to ex vivo experiments. The potency of EMD386088 to blockade dopamine transporter (DAT) was tested in a functional in vitro study. FST was used to assess the involvement of D1- and D2-like receptor subfamilies in antidepressant-like properties of EMD386088. Neurochemical data from ex vivo experiments showed that antiimmobility activity of EMD386088 may be connected with the activation of dopaminergic system, while neither noradrenergic nor serotonergic ones are involved in its effect. EMD386088 also possesses a significant affinity for DAT which may be a mechanism in the abovementioned effect. Behavioral data seem to confirm the importance of dopaminergic system activation in antidepressant-like activity of EMD386088, since this effect, observed in the FST, was abolished by the preferential D1- and D2-like receptor subfamily antagonists SCH23390 and sulpiride, respectively. Dopaminergic system is involved in antidepressant-like activity of EMD386088. PMID:27106213

  14. Active control of electric potential of spacecraft

    NASA Technical Reports Server (NTRS)

    Goldstein, R.

    1977-01-01

    Techniques are discussed for controlling the potential of a spacecraft by means of devices which release appropriate charged particles from the spacecraft to the environment. Attention is given to electron emitters, ion emitters, a basic electron emitter arrangement, techniques for sensing electric field or potential, and flight experiments on active potential control. It is recommended to avoid differential charging on spacecraft surfaces because it can severely affect the efficacy of emitters. Discharging the frame of a spacecraft with dielectric surfaces involves the risk of stressing the dielectric material excessively. The spacecraft should, therefore, be provided with grounded conductive surfaces. It is pointed out that particles released by control systems can return to the spacecraft.

  15. Active control of combustion for optimal performance

    SciTech Connect

    Jackson, M.D.; Agrawal, A.K.

    1999-07-01

    Combustion-zone stoichiometry and fuel-air premixing were actively controlled to optimize the combustor performance over a range of operating conditions. The objective was to maximize the combustion temperature, while maintaining NO{sub x} within a specified limit. The combustion system consisted of a premixer located coaxially near the inlet of a water-cooled shroud. The equivalence ratio was controlled by a variable-speed suction fan located downstream. The split between the premixing air and diffusion air was governed by the distance between the premixer and shroud. The combustor performance was characterized by a cost function evaluated from time-averaged measurements of NO{sub x} and oxygen concentrations in products. The cost function was minimized by downhill simplex algorithm employing closed-loop feedback. Experiments were conducted at different fuel flow rates to demonstrate that the controller optimized the performance without prior knowledge of the combustor behavior.

  16. Distributed control system for active mirrors

    NASA Astrophysics Data System (ADS)

    Rodriguez-Ramos, Luis F.; Williams, Mark R.; Castro, Javier; Cruz, A.; Gonzalez, Juan C.; Mack, Brian; Martin, Carlos; Pescador, German; Sanchez, Vicente; Sosa, Nicolas A.

    1994-06-01

    This paper presents the IAC (Instituto de Astrofisica de Canaries, Spain) proposal of a distributed control system intended for the active support of a 8 m mirror. The system incorporates a large number of compact `smart' force actuators, six force definers, and a mirror support computer (MSC) for interfacing with the telescope control system and for general housekeeping. We propose the use of a network for the interconnection of the actuators, definers and the MSC, which will minimize the physical complexity of the interface between the mirror support system and the MSC. The force actuator control electronics are described in detail, as is the system software architecture of the actuator and the MSC. As the network is a key point for the system, we also detail the evaluation of three candidates, before electing the CAN bus.

  17. a Stochastic Optimal Semi-Active Control Strategy for Er/mr Dampers

    NASA Astrophysics Data System (ADS)

    Ying, Z. G.; Zhu, W. Q.; Soong, T. T.

    2003-01-01

    A stochastic optimal semi-active control strategy for randomly excited systems using electrorheological/magnetorheological (ER/MR) dampers is proposed. A system excited by random loading and controlled by using ER/MR dampers is modelled as a controlled, stochastically excited and dissipated Hamiltonian system with n degrees of freedom. The control forces produced by ER/MR dampers are split into a passive part and an active part. The passive control force is further split into a conservative part and a dissipative part, which are combined with the conservative force and dissipative force of the uncontrolled system, respectively, to form a new Hamiltonian and an overall passive dissipative force. The stochastic averaging method for quasi-Hamiltonian systems is applied to the modified system to obtain partially completed averaged Itô stochastic differential equations. Then, the stochastic dynamical programming principle is applied to the partially averaged Itô equations to establish a dynamical programming equation. The optimal control law is obtained from minimizing the dynamical programming equation subject to the constraints of ER/MR damping forces, and the fully completed averaged Itô equations are obtained from the partially completed averaged Itô equations by replacing the control forces with the optimal control forces and by averaging the terms involving the control forces. Finally, the response of semi-actively controlled system is obtained from solving the final dynamical programming equation and the Fokker-Planck-Kolmogorov equation associated with the fully completed averaged Itô equations of the system. Two examples are given to illustrate the application and effectiveness of the proposed stochastic optimal semi-active control strategy.

  18. Partial purification and characterization of an antimicrobial activity from the wood extract of mangrove plant Ceriops decandra

    PubMed Central

    Simlai, Aritra; Mukherjee, Kalishankar; Mandal, Anurup; Bhattacharya, Kashinath; Samanta, Amalesh; Roy, Amit

    2016-01-01

    The development of resistance towards the antibiotics in use today has been a source of growing concern in the modern healthcare system around the world. To counter this major threat, there is an urgent need for discovery of new antimicrobials. Many plants, like mangroves, possess highly diversified list of natural phytochemicals which are known to have wide range of bioactivities. These phytochemicals can be good sources for the discovery of new drugs. In this study, we report the partial phytochemical characterization and antimicrobial activities of a semi-purified fraction isolated from the wood tissue of Ceriops decandra, a mangrove plant. This fraction named CD-3PM was chromatographically separated from C. decandra wood extract and was subjected to different spectral analyses to determine its partial chemical nature. The structural investigation indicates the presence of two diterpenoids, i) 3β, 13β-Dihydroxy-8-abietaen-7-one and ii) 3β-Hydroxy-8,13-abietadien-7-one in the CD-3PM fraction. The antimicrobial potential of this fraction was evaluated by microdilution-MTT assay against several organisms. Among the nine microorganisms found to be sensitive to the CD-3PM fraction, six organisms are reported to be pathogenic in nature. The CD-3PM fraction with broad spectrum antimicrobial efficacy revealed the presence of two diterpenoids and possesses potential applications in drug discovery process and food processing industries. PMID:27065777

  19. Partial purification and characterization of an antimicrobial activity from the wood extract of mangrove plant Ceriops decandra.

    PubMed

    Simlai, Aritra; Mukherjee, Kalishankar; Mandal, Anurup; Bhattacharya, Kashinath; Samanta, Amalesh; Roy, Amit

    2016-01-01

    The development of resistance towards the antibiotics in use today has been a source of growing concern in the modern healthcare system around the world. To counter this major threat, there is an urgent need for discovery of new antimicrobials. Many plants, like mangroves, possess highly diversified list of natural phytochemicals which are known to have wide range of bioactivities. These phytochemicals can be good sources for the discovery of new drugs. In this study, we report the partial phytochemical characterization and antimicrobial activities of a semi-purified fraction isolated from the wood tissue of Ceriops decandra, a mangrove plant. This fraction named CD-3PM was chromatographically separated from C. decandra wood extract and was subjected to different spectral analyses to determine its partial chemical nature. The structural investigation indicates the presence of two diterpenoids, i) 3β, 13β-Dihydroxy-8-abietaen-7-one and ii) 3β-Hydroxy-8,13-abietadien-7-one in the CD-3PM fraction. The antimicrobial potential of this fraction was evaluated by microdilution-MTT assay against several organisms. Among the nine microorganisms found to be sensitive to the CD-3PM fraction, six organisms are reported to be pathogenic in nature. The CD-3PM fraction with broad spectrum antimicrobial efficacy revealed the presence of two diterpenoids and possesses potential applications in drug discovery process and food processing industries. PMID:27065777

  20. The Middeck Active Control Experiment (MACE)

    NASA Technical Reports Server (NTRS)

    Miller, David W.; Sepe, Raymond B.; Rey, Daniel; Saarmaa, Erik; Crawley, Edward F.

    1993-01-01

    The Middeck Active Control Experiment (MACE) is a NASA In-Step and Control Structure Interaction (CSI) Office funded Shuttle middeck experiment. The objective is to investigate the extent to which closed-loop behavior of flexible spacecraft in zero-gravity (0-g) can be predicted. This prediction becomes particularly difficult when dynamic behavior during ground testing exhibits extensive suspension and direct gravity coupling. On-orbit system identification and control reconfiguration is investigated to improve performance which would otherwise be limited due to errors in prediction. The program is presently in its preliminary design phase with launch expected in the summer of 1994. The MACE test article consists of three attitude control torque wheels, a two axis gimballing payload, inertial sensors and a flexible support structure. With the acquisition of a second payload, this will represent a multiple payload platform with significant structural flexibility. This paper presents on-going work in the areas of modelling and control of the MACE test article in the zero and one-gravity environments. Finite element models, which include suspension and gravity effects, and measurement models, derived from experimental data, are used as the basis for Linear Quadratic Gaussian controller designs. Finite element based controllers are analytically used to study the differences in closed-loop performance as the test article transitions between the 0-g and 1-g environments. Measurement based controllers are experimentally applied to the MACE test article in the 1-g environment and achieve over an order of magnitude improvement in payload pointing accuracy when disturbed by a broadband torque disturbance. The various aspects of the flight portion of the experiment are also discussed.

  1. The Middeck Active Control Experiment (MACE)

    NASA Astrophysics Data System (ADS)

    Miller, David W.; Sepe, Raymond B.; Rey, Daniel; Saarmaa, Erik; Crawley, Edward F.

    1993-02-01

    The Middeck Active Control Experiment (MACE) is a NASA In-Step and Control Structure Interaction (CSI) Office funded Shuttle middeck experiment. The objective is to investigate the extent to which closed-loop behavior of flexible spacecraft in zero-gravity (0-g) can be predicted. This prediction becomes particularly difficult when dynamic behavior during ground testing exhibits extensive suspension and direct gravity coupling. On-orbit system identification and control reconfiguration is investigated to improve performance which would otherwise be limited due to errors in prediction. The program is presently in its preliminary design phase with launch expected in the summer of 1994. The MACE test article consists of three attitude control torque wheels, a two axis gimballing payload, inertial sensors and a flexible support structure. With the acquisition of a second payload, this will represent a multiple payload platform with significant structural flexibility. This paper presents on-going work in the areas of modelling and control of the MACE test article in the zero and one-gravity environments. Finite element models, which include suspension and gravity effects, and measurement models, derived from experimental data, are used as the basis for Linear Quadratic Gaussian controller designs. Finite element based controllers are analytically used to study the differences in closed-loop performance as the test article transitions between the 0-g and 1-g environments. Measurement based controllers are experimentally applied to the MACE test article in the 1-g environment and achieve over an order of magnitude improvement in payload pointing accuracy when disturbed by a broadband torque disturbance. The various aspects of the flight portion of the experiment are also discussed.

  2. Characterization of DicB by partially masking its potent inhibitory activity of cell division.

    PubMed

    Yang, Shaoyuan; Pei, Hairun; Zhang, Xiaoying; Wei, Qiang; Zhu, Jia; Zheng, Jimin; Jia, Zongchao

    2016-07-01

    DicB, a protein encoded by the Kim (Qin) prophage in Escherichia coli, inhibits cell division through interaction with MinC. Thus far, characterization of DicB has been severely hampered owing to its potent activity which ceases cell division and leads to cell death. In this work, through fusing maltose-binding protein to the N-terminus of DicB (MBP-DicB), we successfully expressed and purified recombinant DicB that enabled in vitro analysis for the first time. More importantly, taking advantage of the reduced inhibitory activity of MBP-DicB, we were able to study its effects on cell growth and morphology. Inhibition of cell growth by MBP-DicB was systematically evaluated using various DicB constructs, and their corresponding effects on cell morphology were also investigated. Our results revealed that the N-terminal segment of DicB plays an essential functional role, in contrast to its C-terminal tail. The N-terminus of DicB is of critical importance as even the first amino acid (following the initial Met) could not be removed, although it could be mutated. This study provides the first glimpse of the molecular determinants underlying DicB's function. PMID:27466443

  3. Characterization of DicB by partially masking its potent inhibitory activity of cell division

    PubMed Central

    Yang, Shaoyuan; Pei, Hairun; Zhang, Xiaoying; Wei, Qiang; Zhu, Jia; Zheng, Jimin; Jia, Zongchao

    2016-01-01

    DicB, a protein encoded by the Kim (Qin) prophage in Escherichia coli, inhibits cell division through interaction with MinC. Thus far, characterization of DicB has been severely hampered owing to its potent activity which ceases cell division and leads to cell death. In this work, through fusing maltose-binding protein to the N-terminus of DicB (MBP–DicB), we successfully expressed and purified recombinant DicB that enabled in vitro analysis for the first time. More importantly, taking advantage of the reduced inhibitory activity of MBP–DicB, we were able to study its effects on cell growth and morphology. Inhibition of cell growth by MBP–DicB was systematically evaluated using various DicB constructs, and their corresponding effects on cell morphology were also investigated. Our results revealed that the N-terminal segment of DicB plays an essential functional role, in contrast to its C-terminal tail. The N-terminus of DicB is of critical importance as even the first amino acid (following the initial Met) could not be removed, although it could be mutated. This study provides the first glimpse of the molecular determinants underlying DicB's function. PMID:27466443

  4. Constitutive Activation of the Nlrc4 Inflammasome Prevents Hepatic Fibrosis and Promotes Hepatic Regeneration after Partial Hepatectomy

    PubMed Central

    DeSantis, David A.; Ko, Chih-Wei; Wang, Lan; Lee, Peter; Croniger, Colleen M.

    2015-01-01

    TThe molecular mechanisms responsible for the development of hepatic fibrosis are not fully understood. The Nlrc4 inflammasome detects cytosolic presence of bacterial components, activating inflammatory cytokines to facilitate clearance of pathogens and infected cells. We hypothesized that low-grade constitutive activation of the Nlrc4 inflammasome may lead to induced hepatocyte proliferation and prevent the development of hepatic fibrosis. The gene of Nlrc4 contains two single nucleotide polymorphisms (SNPs), one located within the Nlrc4 promoter and one contained within exon 5. These SNPs regulate Nlrc4 gene transcription and activation as measured through gene reporter assays and IL-1β secretion. The 17C-6 mice have increased IL-1β in plasma after chronic carbon tetrachloride (CCl4) administration compared to B6 mice. After two-thirds partial hepatectomy (2/3PH) 17C-6 mice have earlier restoration of liver mass with greater cyclin D1 protein and BrdU incorporation compared to B6 mice at several time points. These data reveal mild constitutive activation of the Nlrc4 inflammasome as the results of two SNPs, which leads to the stimulation of hepatocyte proliferation. The increased liver regeneration induces rapid liver mass recovery after hepatectomy and may prevent the development of hepatotoxin-induced liver fibrosis. PMID:26635450

  5. Vipegitide: a folded peptidomimetic partial antagonist of α2β1 integrin with antiplatelet aggregation activity

    PubMed Central

    Momic, Tatjana; Katzhendler, Jehoshua; Shai, Ela; Noy, Efrat; Senderowitz, Hanoch; Eble, Johannes A; Marcinkiewicz, Cezary; Varon, David; Lazarovici, Philip

    2015-01-01

    Linear peptides containing the sequence WKTSRTSHY were used as lead compounds to synthesize a novel peptidomimetic antagonist of α2β1 integrin, with platelet aggregation-inhibiting activity, named Vipegitide. Vipegitide is a 13-amino acid, folded peptidomimetic molecule, containing two α-aminoisobutyric acid residues at positions 6 and 8 and not stable in human serum. Substitution of glycine and tryptophan residues at positions 1 and 2, respectively, with a unit of two polyethylene glycol (PEG) molecules yielded peptidomimetic Vipegitide-PEG2, stable in human serum for over 3 hours. Vipegitide and Vipegitide-PEG2 showed high potency (7×10−10 M and 1.5×10−10 M, respectively) and intermediate efficacy (40% and 35%, respectively) as well as selectivity toward α2 integrin in inhibition of adhesion of α1/α2 integrin overexpressing cells toward respective collagens. Interaction of both peptidomimetics with extracellular active domain of α2 integrin was confirmed in cell-free binding assay with recombinant α2 A-domain. Integrin α2β1 receptor is found on the platelet membrane and triggers collagen-induced platelet aggregation. Vipegitide and Vipegitide-PEG2 inhibited α2β1 integrin-mediated adhesion of human and murine platelets under the flow condition, by 50%. They efficiently blocked adenosine diphosphate- and collagen I-induced platelet aggregation in platelet rich plasma and whole human blood. Higher potency of Vipegitide than Vipegitide-PEG2 is consistent with results of computer modeling of the molecules in water. These peptidomimetic molecules were acutely tolerated in mice upon intravenous bolus injection of 50 mg/kg. These results underline the potency of Vipegitide and Vipegitide-PEG2 molecules as platelet aggregation-inhibiting drug lead compounds in antithrombotic therapy. PMID:25609915

  6. Application of active controls to civil transport aircraft

    NASA Technical Reports Server (NTRS)

    Taylor, L. W., Jr.

    1975-01-01

    The impact of active controls on civil transport aircraft and some of the complex problems involved are described. The approach taken by NASA as part of the Active Control Technology Program is discussed to integrate active controls in the conceptual design phase. It is shown that when handled correctly, active controls improve aircraft performance.

  7. Local flow control for active building facades

    NASA Astrophysics Data System (ADS)

    Kaligotla, Srikar; Chen, Wayne; Glauser, Mark

    2010-11-01

    Existing building facade designs are for a passive and an impermeable shell to prevent migration of outdoor air into the building and to control heat transfers between the exterior environment and the building interior. An active facade that can respond in real time to changing environmental conditions like wind speed and direction, pollutant load, temperature, humidity and light can lower energy use and maximize occupant comfort. With an increased awareness of cost and environmental effects of energy use, cross or natural ventilation has become an attractive method to lower energy use. Separated flow regions around such buildings are undesirable due to high concentration of pollutants, especially if the vents or dynamic windows for cross ventilation are situated in these regions. Outside pollutant load redistribution through vents can be regulated via flow separation control to minimize transport of pollutants into the building. Flow separation has been substantially reduced with the application of intelligent flow control tools developed at Syracuse University for flow around "silo" (turret) like structures. Similar flow control models can be introduced into buildings with cross ventilation for local external flow separation control. Initial experiments will be performed for turbulent flow over a rectangular block (scaled to be a mid-rise building) that has been configured with dynamic vents and unsteady suction actuators in a wind tunnel at various wind speeds.

  8. Middeck Active Control Experiment (MACE), phase A

    NASA Technical Reports Server (NTRS)

    Crawley, Edward F.; Deluis, Javier; Miller, David W.

    1989-01-01

    A rationale to determine which structural experiments are sufficient to verify the design of structures employing Controlled Structures Technology was derived. A survey of proposed NASA missions was undertaken to identify candidate test articles for use in the Middeck Active Control Experiment (MACE). The survey revealed that potential test articles could be classified into one of three roles: development, demonstration, and qualification, depending on the maturity of the technology and the mission the structure must fulfill. A set of criteria was derived that allowed determination of which role a potential test article must fulfill. A review of the capabilities and limitations of the STS middeck was conducted. A reference design for the MACE test article was presented. Computing requirements for running typical closed-loop controllers was determined, and various computer configurations were studied. The various components required to manufacture the structure were identified. A management plan was established for the remainder of the program experiment development, flight and ground systems development, and integration to the carrier. Procedures for configuration control, fiscal control, and safety, reliabilty, and quality assurance were developed.

  9. Vibration control of cylindrical shells using active constrained layer damping

    NASA Astrophysics Data System (ADS)

    Ray, Manas C.; Chen, Tung-Huei; Baz, Amr M.

    1997-05-01

    The fundamentals of controlling the structural vibration of cylindrical shells treated with active constrained layer damping (ACLD) treatments are presented. The effectiveness of the ACLD treatments in enhancing the damping characteristics of thin cylindrical shells is demonstrated theoretically and experimentally. A finite element model (FEM) is developed to describe the dynamic interaction between the shells and the ACLD treatments. The FEM is used to predict the natural frequencies and the modal loss factors of shells which are partially treated with patches of the ACLD treatments. The predictions of the FEM are validated experimentally using stainless steel cylinders which are 20.32 cm in diameter, 30.4 cm in length and 0.05 cm in thickness. The cylinders are treated with ACLD patches of different configurations in order to target single or multi-modes of lobar vibrations. The ACLD patches used are made of DYAD 606 visco-elastic layer which is sandwiched between two layers of PVDF piezo-electric films. Vibration attenuations of 85% are obtained with maximum control voltage of 40 volts. Such attenuations are attributed to the effectiveness of the ACLD treatment in increasing the modal damping ratios by about a factor of four over those of conventional passive constrained layer damping (PCLD) treatments. The obtained results suggest the potential of the ACLD treatments in controlling the vibration of cylindrical shells which constitute the major building block of many critical structures such as cabins of aircrafts, hulls of submarines and bodies of rockets and missiles.

  10. Multigrid block preconditioning for a coupled system of partial differential equations modeling the electrical activity in the heart.

    PubMed

    Sundnes, J; Lines, G T; Mardal, K A; Tveito, A

    2002-12-01

    The electrical activity of the heart may be modeled with a system of partial differential equations (PDEs) known as the bidomain model. Computer simulations based on these equations may become a helpful tool to understand the relationship between changes in the electrical field and various heart diseases. Because of the rapid variations in the electrical field, sufficiently accurate simulations require a fine-scale discretization of the equations. For realistic geometries this leads to a large number of grid points and consequently large linear systems to be solved for each time step. In this paper, we present a fully coupled discretization of the bidomain model, leading to a block structured linear system. We take advantage of the block structure to construct an efficient preconditioner for the linear system, by combining multigrid with an operator splitting technique. PMID:12468421

  11. Rare earth oxide-doped titania nanocomposites with enhanced photocatalytic activity towards the degradation of partially hydrolysis polyacrylamide

    NASA Astrophysics Data System (ADS)

    Li, Jinhuan; Yang, Xia; Yu, Xiaodan; Xu, Leilei; Kang, Wanli; Yan, Wenhua; Gao, Hongfeng; Liu, Zhonghe; Guo, Yihang

    2009-01-01

    Rare-earth oxide-doped titania nanocomposites (RE 3+/TiO 2, where RE = Eu 3+, Pr 3+, Gd 3+, Nd 3+, and Y 3+) were prepared by a one-step sol-gel-solvothermal method. The products exhibited anatase phase structure, mesoporosity, and interesting surface compositions with three oxygen species and two titanium species. The products were used as the photocatalysts to degrade a partially hydrolysis polyacrylamide (HPAM) under UV-light irradiation, a very useful polymer in oil recovery. For comparison, Degussa P25 and as-prepared pure TiO 2 were also tested under the same conditions. The enhanced photocatalytic activity was obtained on as-prepared Eu 3+ (Gd 3+, Pr 3+)/TiO 2 composites, and the reasons were explained. Finally, the degradation pathway of HPAM over the RE 3+/TiO 2 composite was put forward based on the intermediates produced during the photocatalysis procedure.

  12. Childhood lead exposure in France: benefit estimation and partial cost-benefit analysis of lead hazard control

    PubMed Central

    2011-01-01

    Background Lead exposure remains a public health concern due to its serious adverse effects, such as cognitive and behavioral impairment: children younger than six years of age being the most vulnerable population. In Europe, the lead-related economic impacts have not been examined in detail. We estimate the annual costs in France due to childhood exposure and, through a cost benefit analysis (CBA), aim to assess the expected social and economic benefits of exposure abatement. Methods Monetary benefits were assessed in terms of avoided national costs. We used results from a 2008 survey on blood-lead (B-Pb) concentrations in French children aged one to six years old. Given the absence of a threshold concentration being established, we performed a sensitivity analysis assuming different hypothetical threshold values for toxicity above 15 μg/L, 24 μg/L and 100 μg/L. Adverse health outcomes of lead exposure were translated into social burden and economic costs based on literature data from literature. Direct health benefits, social benefits and intangible avoided costs were included. Costs of pollutant exposure control were partially estimated in regard to homes lead-based paint decontamination, investments aiming at reducing industrial lead emissions and removal of all lead drinking water pipes. Results The following overall annual benefits for the three hypothetical thresholds values in 2008 are: €22.72 billion, €10.72 billion and €0.44 billion, respectively. Costs from abatement ranged from €0.9 billion to 2.95 billion/year. Finally, from a partial CBA of lead control in soils and dust the estimates of total net benefits were € 3.78 billion, € 1.88 billion and €0.25 billion respectively for the three hypothesized B-Pb effect values. Conclusions Prevention of childhood lead exposure has a high social benefit, due to reduction of B-Pb concentrations to levels below 15 μg/L or 24 μg/L, respectively. Reducing only exposures above 100 μg/L B-Pb has

  13. The role of chordin fragments generated by partial tolloid cleavage in regulating BMP activity.

    PubMed

    Troilo, Helen; Barrett, Anne L; Wohl, Alexander P; Jowitt, Thomas A; Collins, Richard F; Bayley, Christopher P; Zuk, Alexandra V; Sengle, Gerhard; Baldock, Clair

    2015-10-01

    Chordin-mediated regulation of bone morphogenetic protein (BMP) family growth factors is essential in early embryogenesis and adult homoeostasis. Chordin binds to BMPs through cysteine-rich von Willebrand factor type C (vWC) homology domains and blocks them from interacting with their cell surface receptors. These domains also self-associate and enable chordin to target related proteins to fine-tune BMP regulation. The chordin-BMP inhibitory complex is strengthened by the secreted glycoprotein twisted gastrulation (Tsg); however, inhibition is relieved by cleavage of chordin at two specific sites by tolloid family metalloproteases. As Tsg enhances this cleavage process, it serves a dual role as both promoter and inhibitor of BMP signalling. Recent developments in chordin research suggest that rather than simply being by-products, the cleavage fragments of chordin continue to play a role in BMP regulation. In particular, chordin cleavage at the C-terminus potentiates its anti-BMP activity in a type-specific manner. PMID:26517884

  14. The role of chordin fragments generated by partial tolloid cleavage in regulating BMP activity

    PubMed Central

    Troilo, Helen; Barrett, Anne L.; Wohl, Alexander P.; Jowitt, Thomas A.; Collins, Richard F.; Bayley, Christopher P.; Zuk, Alexandra V.; Sengle, Gerhard; Baldock, Clair

    2015-01-01

    Chordin-mediated regulation of bone morphogenetic protein (BMP) family growth factors is essential in early embryogenesis and adult homoeostasis. Chordin binds to BMPs through cysteine-rich von Willebrand factor type C (vWC) homology domains and blocks them from interacting with their cell surface receptors. These domains also self-associate and enable chordin to target related proteins to fine-tune BMP regulation. The chordin–BMP inhibitory complex is strengthened by the secreted glycoprotein twisted gastrulation (Tsg); however, inhibition is relieved by cleavage of chordin at two specific sites by tolloid family metalloproteases. As Tsg enhances this cleavage process, it serves a dual role as both promoter and inhibitor of BMP signalling. Recent developments in chordin research suggest that rather than simply being by-products, the cleavage fragments of chordin continue to play a role in BMP regulation. In particular, chordin cleavage at the C-terminus potentiates its anti-BMP activity in a type-specific manner. PMID:26517884

  15. Local electronic structure and photoelectrochemical activity of partial chemically etched Ti-doped hematite

    NASA Astrophysics Data System (ADS)

    Rioult, Maxime; Belkhou, Rachid; Magnan, Hélène; Stanescu, Dana; Stanescu, Stefan; Maccherozzi, Francesco; Rountree, Cindy; Barbier, Antoine

    2015-11-01

    The direct conversion of solar light into chemical energy or fuel through photoelectrochemical water splitting is promising as a clean hydrogen production solution. Ti-doped hematite (Ti:α-Fe2O3) is a potential key photoanode material, which despite its optimal band gap, excellent chemical stability, abundance, non-toxicity and low cost, still has to be improved. Here we give evidence of a drastic improvement of the water splitting performances of Ti-doped hematite photoanodes upon a HCl wet-etching. In addition to the topography investigation by atomic force microscopy, a detailed determination of the local electronic structure has been carried out in order to understand the phenomenon and to provide new insights in the understanding of solar water splitting. Using synchrotron radiation based spectromicroscopy (X-PEEM), we investigated the X-ray absorption spectral features at the L3 Fe edge of the as grown surface and of the wet-etched surface on the very same sample thanks to patterning. We show that HCl wet etching leads to substantial surface modifications of the oxide layer including increased roughness and chemical reduction (presence of Fe2 +) without changing the band gap. We demonstrate that these changes are profitable and correlated to the drastic changes of the photocatalytic activity.

  16. Partial characterization of cold active amylases and proteases of Streptomyces sp. from Antarctica

    PubMed Central

    Cotârleţ, Mihaela; Negoiţă, Teodor Gh.; Bahrim, Gabriela E.; Stougaard, Peter

    2011-01-01

    The aim of this study was to isolate novel enzyme-producing bacteria from vegetation samples from East Antarctica and also to characterize them genetically and biochemically in order to establish their phylogeny. The ability to grow at low temperature and to produce amylases and proteases cold-active was also tested. The results of the 16S rRNA gene sequence analysis showed that the 4 Alga rRNA was 100% identical to the sequences of Streptomyces sp. rRNA from Norway and from the Solomon Islands. The Streptomyces grew well in submerged system at 20°C, cells multiplication up to stationary phase being drastically increased after 120 h of submerged cultivation. The beta-amylase production reached a maximum peak after seven days, while alpha-amylase and proteases were performing biosynthesis after nine days of submerged cultivation at 20°C. Newly Streptomyces were able to produce amylase and proteases in a cold environment. The ability to adapt to low temperature of these enzymes could make them valuable ingredients for detergents, the food industry and bioremediation processes which require low temperatures. PMID:24031702

  17. Nanoparticle Mediated Remote Control of Enzymatic Activity

    PubMed Central

    Knecht, Leslie D.; Ali, Nur; Wei, Yinan; Hilt, J. Zach; Daunert, Sylvia

    2012-01-01

    Nanomaterials have found numerous applications as tunable, remotely controlled platforms for drug delivery, hyperthermia cancer treatment, and various other biomedical applications. The basis for the interest lies in their unique properties achieved at the nanoscale that can be accessed via remote stimuli. These properties could then be exploited to simultaneously activate secondary systems that are not remotely actuatable. In this work, iron oxide nanoparticles are encapsulated in a bisacrylamide-crosslinked polyacrylamide hydrogel network along with a model dehalogenase enzyme, L-2-HADST. This thermophilic enzyme is activated at elevated temperatures and has been shown to have optimal activity at 70 °C. By exposing the Fe3O4 nanoparticles to a remote stimulus, an alternating magnetic field (AMF), enhanced system heating can be achieved, thus remotely activating the enzyme. The internal heating of the nanocomposite hydrogel network in the AMF results in a 2-fold increase in enzymatic activity as compared to the same hydrogel heated externally in a water bath, suggesting that the internal heating of the nanoparticles is more efficient than the diffusion limited heating of the water bath. This system may prove useful for remote actuation of biomedical and environmentally relevant enzymes and find applications in a variety of fields. PMID:22989219

  18. Photo-active collagen systems with controlled triple helix architecture

    PubMed Central

    Tronci, Giuseppe; Russell, Stephen J.; Wood, David J.

    2016-01-01

    The design of photo-active collagen systems is presented as a basis for establishing biomimetic materials with varied network architecture and programmable macroscopic properties. Following in-house isolation of type I collagen, reaction with vinyl-bearing compounds of varied backbone rigidity, i.e. 4-vinylbenzyl chloride (4VBC) and glycidyl methacrylate (GMA), was carried out. TNBS colorimetric assay, 1H-NMR and ATR-FTIR confirmed covalent and tunable functionalization of collagen lysines. Depending on the type and extent of functionalization, controlled stability and thermal denaturation of triple helices were observed via circular dichroism (CD), whereby the hydrogen-bonding capability of introduced moieties was shown to play a major role. Full gel formation was observed following photo-activation of functionalized collagen solutions. The presence of a covalent network only slightly affected collagen triple helix conformation (as observed by WAXS and ATR-FTIR), confirming the structural organization of functionalized collagen precursors. Photo-activated hydrogels demonstrated an increased denaturation temperature (DSC) with respect to native collagen, suggesting that the formation of the covalent network successfully stabilized collagen triple helices. Moreover, biocompatibility and mechanical competence of obtained hydrogels were successfully demonstrated under physiologically-relevant conditions. These results demonstrate that this novel synthetic approach enabled the formation of biocompatible collagen systems with defined network architecture and programmable macroscopic properties, which can only partially be obtained with current synthetic methods.

  19. C-Terminal extension of a plant cysteine protease modulates proteolytic activity through a partial inhibitory mechanism.

    PubMed

    Dutta, Sruti; Choudhury, Debi; Dattagupta, Jiban K; Biswas, Sampa

    2011-09-01

    The amino acid sequence of ervatamin-C, a thermostable cysteine protease from a tropical plant, revealed an additional 24-amino-acid extension at its C-terminus (CT). The role of this extension peptide in zymogen activation, catalytic activity, folding and stability of the protease is reported. For this study, we expressed two recombinant forms of the protease in Escherichia coli, one retaining the CT-extension and the other with it truncated. The enzyme with the extension shows autocatalytic zymogen activation at a higher pH of 8.0, whereas deletion of the extension results in a more active form of the enzyme. This CT-extension was not found to be cleaved during autocatalysis or by limited proteolysis by different external proteases. Molecular modeling and simulation studies revealed that the CT-extension blocks some of the substrate-binding unprimed subsites including the specificity-determining subsite (S2) of the enzyme and thereby partially occludes accessibility of the substrates to the active site, which also corroborates the experimental observations. The CT-extension in the model structure shows tight packing with the catalytic domain of the enzyme, mediated by strong hydrophobic and H-bond interactions, thus restricting accessibility of its cleavage sites to the protease itself or to the external proteases. Kinetic stability analyses (T(50) and t(1/2) ) and refolding experiments show similar thermal stability and refolding efficiency for both forms. These data suggest that the CT-extension has an inhibitory role in the proteolytic activity of ervatamin-C but does not have a major role either in stabilizing the enzyme or in its folding mechanism. PMID:21707922

  20. Steviol and steviol-glycoside: glucosyltransferase activities in Stevia rebaudiana Bertoni--purification and partial characterization.

    PubMed

    Shibata, H; Sawa, Y; Oka, T; Sonoke, S; Kim, K K; Yoshioka, M

    1995-08-20

    The leaves of Stevia rebaudiana Bertoni contain sweet compounds which are glycosides of diterpene derivative steviol (ent-13-hydroxykaur-16-en-19-oic acid). Its main constituents are stevioside (triglucosylated steviol; 13-O-beta-sophorosyl-19-O-beta-glucosyl-steviol) and rebaudioside-A (tetraglucosylated steviol; 2'-O-beta-glucosyl-13-O-beta-sophorosyl-19-O-beta-glucosyl-stev iol). From the extracts of S. rebaudiana Bertoni, two glucosyltransferases (GTases I and IIB) acting on steviol and steviol-glycosides were isolated, and another distinct activity (GTase IIA) acting on steviol was detected. Purified GTase I (subunit M(r) 24,600) catalyzed glucose transfer from UDP-glucose to steviol and steviolmonoside (steviol-13-O-glucopyranoside), but not to other steviol-glycosides. Apparent Km values were 71.4 microM for steviol and 360 microM for UDP-glucose. GTase IIB (subunit M(r) 30,700) showed a broad substrate specificity, acting on steviol, steviolmonoside, steviolbioside (13-O-beta-sophorosyl-steviol), and stevioside. Apparent Km values were 182 microM for steviol, 44 microM for steviolbioside, 95 microM for stevioside, and 385 microM for UDP-glucose. The two enzymes had a similar optimum pH at 6.5. They also acted effectively on ubiquitous flavonol aglycones, quercetin, and kaempferol and utilized kaempferol at a higher rate than steviol and steviol-glycosides. The apparent Km values of GTase I and IIB for kaempferol were 12 and 31 microM, respectively. PMID:7646064

  1. Partial Antiviral Activities Detection of Chicken Mx Jointing with Neuraminidase Gene (NA) against Newcastle Disease Virus

    PubMed Central

    Zhang, Yani; Fu, Dezhi; Chen, Hao; Zhang, Zhentao; Shi, Qingqing; Elsayed, Ahmed Kamel; Li, Bichun

    2013-01-01

    As an attempt to increase the resistance to Newcastle Disease Virus (NDV) and so further reduction of its risk on the poultry industry. This work aimed to build the eukaryotic gene co-expression plasmid of neuraminidase (NA) gene and myxo-virus resistance (Mx) and detect the gene expression in transfected mouse fibroblasts (NIH-3T3) cells, it is most important to investigate the influence of the recombinant plasmid on the chicken embryonic fibroblasts (CEF) cells. cDNA fragment of NA and mutant Mx gene were derived from pcDNA3.0-NA and pcDNA3.0-Mx plasmid via PCR, respectively, then NA and Mx cDNA fragment were inserted into the multiple cloning sites of pVITRO2 to generate the eukaryotic co-expression plasmid pVITRO2-Mx-NA. The recombinant plasmid was confirmed by restriction endonuclease treatment and sequencing, and it was transfected into the mouse fibroblasts (NIH-3T3) cells. The expression of genes in pVITRO2-Mx-NA were measured by RT-PCR and indirect immunofluorescence assay (IFA). The recombinant plasmid was transfected into CEF cells then RT-PCR and the micro-cell inhibition tests were used to test the antiviral activity for NDV. Our results showed that co-expression vector pVITRO2-Mx-NA was constructed successfully; the expression of Mx and NA could be detected in both NIH-3T3 and CEF cells. The recombinant proteins of Mx and NA protect CEF cells from NDV infection until after 72 h of incubation but the individually mutagenic Mx protein or NA protein protects CEF cells from NDV infection till 48 h post-infection, and co-transfection group decreased significantly NDV infection compared with single-gene transfection group (P<0. 05), indicating that Mx-NA jointing contributed to delaying the infection of NDV in single-cell level and the co-transfection of the jointed genes was more powerful than single one due to their synergistic effects. PMID:23977111

  2. Apoptin T108 phosphorylation is not required for its tumor-specific nuclear localization but partially affects its apoptotic activity

    SciTech Connect

    Lee, Y.-H.; Cheng, C.-M.; Chang, Y.-F.; Wang, T.-Y.; Yuo, C.-Y.; E-mail: m815006@kmu.edu.tw

    2007-03-09

    Apoptin, a chicken anemia virus-encoded protein, induces apoptosis in human tumor cells but not in normal cells. In addition, Apoptin also exhibits tumor-specific nuclear localization and tumor-specific phosphorylation on threonine 108 (T108). Here, we studied the effects of T108 phosphorylation on the tumor-specific nuclear localization and apoptotic activity of Apoptin. We first showed that a hemagglutinin (HA)-tagged Apoptin, but not the green fluorescent protein-fused Apoptin used in many previous studies, exhibited the same intracellular distribution pattern as native Apoptin. We then made and analyzed an HA-Apoptin mutant with its T108 phosphorylation site abolished. We found that Apoptin T108 phosphorylation is not required for its tumor-specific nuclear localization and abolishing the T108 phosphorylation of Apoptin does affect its apoptotic activity in tumor cells but only partially. Our results support the previous finding that Apoptin contains two distinct apoptosis domains located separately at the N- and C-terminal regions and suggest that the T108 phosphorylation may only be required for the apoptotic activity mediated through the C-terminal apoptosis domain.

  3. Novel thrombolytic protease from edible and medicinal plant Aster yomena (Kitam.) Honda with anticoagulant activity: purification and partial characterization.

    PubMed

    Choi, Jun-Hui; Kim, Dae-Won; Park, Se-Eun; Choi, Bong-Suk; Sapkota, Kumar; Kim, Seung; Kim, Sung-Jun

    2014-10-01

    A thrombolytic protease named kitamase possessing anticoagulant property was purified from edible and medicinal plant Aster yomena (Kitam.) Honda. Kitamase showed a molecular weight of 50 kDa by SDS-PAGE and displayed a strong fibrin zymogram lysis band corresponding to the similar molecular mass. The enzyme was active at high temperatures (50°C). The fibrinolytic activity of kitamase was strongly inhibited by EDTA, EGTA, TPCK and PMSF, inhibited by Zn(2+). The Km and Vmax values for substrate S-2251 were determined as 4.31 mM and 23.81 mM/mg respectively. It dissolved fibrin clot directly and specifically cleaved the α, Aα and γ-γ chains of fibrin and fibrinogen. In addition, kitamase delayed the coagulation time and increased activated partial thromboplastin time and prothrombin time. Kitamase exerted a significant protective effect against collagen and epinephrine induced pulmonary thromboembolism in mice. These results suggest that kitamase may have the property of metallo-protease like enzyme, novel fibrino(geno)lytic enzyme and a potential to be a therapeutic agent for thrombosis. PMID:24746735

  4. Radiation inactivation analysis of assimilatory NADH:nitrate reductase. Apparent functional sizes of partial activities associated with intact and proteolytically modified enzyme

    SciTech Connect

    Solomonson, L.P.; McCreery, M.J.; Kay, C.J.; Barber, M.J.

    1987-06-25

    Recently we demonstrated that target sizes for the partial activities of nitrate reductase were considerably smaller than the 100-kDa subunit which corresponded to the target size of the full (physiologic) activity NADH:nitrate reductase. These results suggested that the partial activities resided on functionally independent domains and that radiation inactivation may be due to localized rather than extensive damage to protein structure. The present study extends these observations and addresses several associated questions. Monophasic plots were observed over a wide range of radiation doses, suggesting a single activity component in each case. No apparent differences were observed over a 10-fold range of concentration for each substrate, suggesting that the observed slopes were not due to marked changes in Km values. Apparent target sizes estimated for partial activities associated with native enzyme and with limited proteolysis products of native enzyme suggested that the functional size obtained by radiation inactivation analysis is independent of the size of the polypeptide chain. The presence of free radical scavengers during irradiation reduced the apparent target size of both the physiologic and partial activities by an amount ranging from 24 to 43%, suggesting that a free radical mechanism is at least partially responsible for the inactivation. Immunoblot analysis of nitrate reductase irradiated in the presence of free radical scavengers revealed formation of distinct bands at 90, 75, and 40 kDa with increasing doses of irradiation rather than complete destruction of the polypeptide chain.

  5. Active Displacement Control of Active Magnetic Bearing System

    NASA Astrophysics Data System (ADS)

    Kertész, Milan; Kozakovič, Radko; Magdolen, Luboš; Masaryk, Michal

    2014-12-01

    The worldwide energy production nowadays is over 3400 GW while storage systems have a capacity of only 90 GW [1]. There is a good solution for additional storage capacity in flywheel energy storage systems (FES). The main advantage of FES is its relatively high efficiency especially with using the active magnetic bearing system. Therefore there exist good reasons for appropriate simulations and for creating a suitable magneto-structural control system. The magnetic bearing, including actuation, is simulated in the ANSYS parametric design language (APDL). APDL is used to create the loops of transient simulations where boundary conditions (BC) are updated based upon a "gap sensor" which controls the nodal position values of the centroid of the shaft and the current density inputs onto the copper windings.

  6. Understanding the brain by controlling neural activity

    PubMed Central

    Krug, Kristine; Salzman, C. Daniel; Waddell, Scott

    2015-01-01

    Causal methods to interrogate brain function have been employed since the advent of modern neuroscience in the nineteenth century. Initially, randomly placed electrodes and stimulation of parts of the living brain were used to localize specific functions to these areas. Recent technical developments have rejuvenated this approach by providing more precise tools to dissect the neural circuits underlying behaviour, perception and cognition. Carefully controlled behavioural experiments have been combined with electrical devices, targeted genetically encoded tools and neurochemical approaches to manipulate information processing in the brain. The ability to control brain activity in these ways not only deepens our understanding of brain function but also provides new avenues for clinical intervention, particularly in conditions where brain processing has gone awry. PMID:26240417

  7. Control concepts for active magnetic bearings

    NASA Technical Reports Server (NTRS)

    Siegwart, Roland; Vischer, D.; Larsonneur, R.; Herzog, R.; Traxler, Alfons; Bleuler, H.; Schweitzer, G.

    1992-01-01

    Active Magnetic Bearings (AMB) are becoming increasingly significant for various industrial applications. Examples are turbo-compressors, centrifuges, high speed milling and grinding spindles, vibration isolation, linear guides, magnetically levitated trains, vacuum and space applications. Thanks to the rapid progress and drastic cost reduction in power- and micro-electronics, the number of AMB applications is growing very rapidly. Industrial uses of AMBs leads to new requirements for AMB-actuators, sensor systems, and rotor dynamics. Especially desirable are new and better control concepts to meet demand such as low cost AMB, high stiffness, high performance, high robustness, high damping up to several kHz, vibration isolation, force-free rotation, and unbalance cancellation. This paper surveys various control concepts for AMBs and discusses their advantages and disadvantages. Theoretical and experimental results are presented.

  8. Gas turbine engine active clearance control

    NASA Technical Reports Server (NTRS)

    Deveau, Paul J. (Inventor); Greenberg, Paul B. (Inventor); Paolillo, Roger E. (Inventor)

    1985-01-01

    Method for controlling the clearance between rotating and stationary components of a gas turbine engine are disclosed. Techniques for achieving close correspondence between the radial position of rotor blade tips and the circumscribing outer air seals are disclosed. In one embodiment turbine case temperature modifying air is provided in flow rate, pressure and temperature varied as a function of engine operating condition. The modifying air is scheduled from a modulating and mixing valve supplied with dual source compressor air. One source supplies relatively low pressure, low temperature air and the other source supplies relatively high pressure, high temperature air. After the air has been used for the active clearance control (cooling the high pressure turbine case) it is then used for cooling the structure that supports the outer air seal and other high pressure turbine component parts.

  9. Effect of partial genetic resistance on efficacy of Topsin fungicide for control of white mold disease in pinto bean

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Pinto bean is the most important dry bean market class grown in the U.S., but is one of the most susceptible to white mold disease. Developing pinto bean with partial resistance is a major goal of plant breeders, but the effect of partial resistance on efficacy of fungicide application for disease m...

  10. On the Green's function of the partially diffusion-controlled reversible ABCD reaction for radiation chemistry codes

    NASA Astrophysics Data System (ADS)

    Plante, Ianik; Devroye, Luc

    2015-09-01

    Several computer codes simulating chemical reactions in particles systems are based on the Green's functions of the diffusion equation (GFDE). Indeed, many types of chemical systems have been simulated using the exact GFDE, which has also become the gold standard for validating other theoretical models. In this work, a simulation algorithm is presented to sample the interparticle distance for partially diffusion-controlled reversible ABCD reaction. This algorithm is considered exact for 2-particles systems, is faster than conventional look-up tables and uses only a few kilobytes of memory. The simulation results obtained with this method are compared with those obtained with the independent reaction times (IRT) method. This work is part of our effort in developing models to understand the role of chemical reactions in the radiation effects on cells and tissues and may eventually be included in event-based models of space radiation risks. However, as many reactions are of this type in biological systems, this algorithm might play a pivotal role in future simulation programs not only in radiation chemistry, but also in the simulation of biochemical networks in time and space as well.

  11. On the Green's function of the partially diffusion-controlled reversible ABCD reaction for radiation chemistry codes

    SciTech Connect

    Plante, Ianik; Devroye, Luc

    2015-09-15

    Several computer codes simulating chemical reactions in particles systems are based on the Green's functions of the diffusion equation (GFDE). Indeed, many types of chemical systems have been simulated using the exact GFDE, which has also become the gold standard for validating other theoretical models. In this work, a simulation algorithm is presented to sample the interparticle distance for partially diffusion-controlled reversible ABCD reaction. This algorithm is considered exact for 2-particles systems, is faster than conventional look-up tables and uses only a few kilobytes of memory. The simulation results obtained with this method are compared with those obtained with the independent reaction times (IRT) method. This work is part of our effort in developing models to understand the role of chemical reactions in the radiation effects on cells and tissues and may eventually be included in event-based models of space radiation risks. However, as many reactions are of this type in biological systems, this algorithm might play a pivotal role in future simulation programs not only in radiation chemistry, but also in the simulation of biochemical networks in time and space as well.

  12. Fano line-shape control and superluminal light using cavity quantum electrodynamics with a partially transmitting element

    NASA Astrophysics Data System (ADS)

    Li, Jiahua; Yu, Rong; Liu, Jiuyang; Ding, Chunling; Wu, Ying

    2016-05-01

    We study the probe-field transmission in cavity quantum electrodynamics (cavity-QED) systems with a partially transmitting element (PTE), where the PTE is used to control and tune the amplitude of the weak probe field propagating along a single waveguide channel in the structure. We derive analytic formulas utilized to determine the transmission coefficient of the probe field within the framework of quantum optics. Using experimentally accessible parameters, it is clearly shown that the asymmetric Fano-resonance line shape can be formed and manipulated by means of the added PTE. Furthermore, we reveal that there exists superluminal light with large intensity transmission in the transport spectrum of the waveguide-coupled cavity-QED system. This superluminal-light propagation effect, which exhibits the anomalous phase shift and is characterized by the negative group delay, can be enhanced by properly choosing the system parameters. The obtained results may be used for designing switching, modulation, and sensing for nanophotonic applications and ultrafast on-chip signal processing in telecom applications.

  13. Active Aircraft Pylon Noise Control System

    NASA Technical Reports Server (NTRS)

    Thomas, Russell H. (Inventor); Czech, Michael J (Inventor); Elmiligui, Alaa A. (Inventor)

    2015-01-01

    An active pylon noise control system for an aircraft includes a pylon structure connecting an engine system with an airframe surface of the aircraft and having at least one aperture to supply a gas or fluid therethrough, an intake portion attached to the pylon structure to intake a gas or fluid, a regulator connected with the intake portion via a plurality of pipes, to regulate a pressure of the gas or fluid, a plenum chamber formed within the pylon structure and connected with the regulator, and configured to receive the gas or fluid as regulated by the regulator, and a plurality of injectors in communication with the plenum chamber to actively inject the gas or fluid through the plurality of apertures of the pylon structure.

  14. Telmisartan protects against diabetic vascular complications in a mouse model of obesity and type 2 diabetes, partially through peroxisome proliferator activated receptor-{gamma}-dependent activity

    SciTech Connect

    Toyama, Kensuke; Nakamura, Taishi; Kataoka, Keiichiro; Yasuda, Osamu; Fukuda, Masaya; Tokutomi, Yoshiko; Dong, Yi-Fei; Ogawa, Hisao; Kim-Mitsuyama, Shokei

    2011-07-08

    Highlights: {yields} Telmisartan, an angiotensin receptor blocker, acts as a partial PPAR{gamma} agonist. {yields} The protective effects of telmisartan against diabetic vascular injury were associated with attenuation of vascular NF{kappa}B activation and TNF {alpha}. {yields} PPAR{gamma} activity of telmisartan was involved in the normalization of vascular PPAR{gamma} downregulation in diabetic mice. {yields} We provided the first evidence indicating that PPAR{gamma} activity of telmisartan contributed to the protective effects of telmisartan against diabetic vascular complication. -- Abstract: Experimental and clinical data support the notion that peroxisome proliferator-activated receptor {gamma} (PPAR{gamma}) activation is associated with anti-atherosclerosis as well as anti-diabetic effect. Telmisartan, an angiotensin receptor blocker (ARB), acts as a partial PPAR{gamma} agonist. We hypothesized that telmisartan protects against diabetic vascular complications, through PPAR{gamma} activation. We compared the effects of telmisartan, telmisartan combined with GW9662 (a PPAR{gamma} antagonist), and losartan with no PPAR{gamma} activity on vascular injury in obese type 2 diabetic db/db mice. Compared to losartan, telmisartan significantly ameliorated vascular endothelial dysfunction, downregulation of phospho-eNOS, and coronary arterial remodeling in db/db mice. More vascular protective effects of telmisartan than losartan were associated with greater anti-inflammatory effects of telmisartan, as shown by attenuation of vascular nuclear factor kappa B (NF{kappa}B) activation and tumor necrosis factor {alpha}. Coadministration of GW9662 with telmisartan abolished the above mentioned greater protective effects of telmisartan against vascular injury than losartan in db/db mice. Thus, PPAR{gamma} activity appears to be involved in the vascular protective effects of telmisartan in db/db mice. Moreover, telmisartan, but not losartan, prevented the downregulation of

  15. Influence of factor VIII:C and factor IX activity in plasmas of haemophilic dogs on the activated partial thromboplastin time measured with two commercial reagents.

    PubMed

    Mischke, R

    2000-05-01

    The present study is based on 145 plasma samples with a reduced activity of factor VIII:C (range: 0.009-0.62 IU mL-1) and 28 samples with a reduced factor IX activity (range: 0.035-0.55 IU mL-1). The samples were collected from dogs with haemophilia A (n=22) or haemophilia B (n=3), some of these during substitution therapy. For all samples the activated partial thromboplastin time (APTT) was measured with two commercial reagents containing kaolin as a contact activator. In each case, the deficiency of factor VIII:C or IX was reflected in abnormal results of the APTT. This was true for both reagents. A significant correlation (P < 0.001) was found between factor VIII:C activity and APTT (reagent 1, Pathromtin(R); Spearman's rank correlation coefficient, rS=-0.731, reagent 2, PTT-Reagenz; rS=-0.875) as well as between factor IX activity and APTT (reagent 1, rS=-0.819; reagent 2, rS=-0.955]. In each case, the relationship between coagulation factor activity and APTT could be proven most precisely by geometric regression. The results of this study illustrate the applicability of commercial APTT test kits as a sensitive screening test of factor VIII:C and IX deficiencies in canine plasma. PMID:10792470

  16. Control of flexible beams using a free-free active truss

    NASA Technical Reports Server (NTRS)

    Clark, W. W.; Kimiavi, B.; Robertshaw, H. H.

    1989-01-01

    An analytical and experimental study involving controlling flexible beams using a free-free active truss is presented. This work extends previous work in controlling flexible continua with active trusses which were configured with fixed-free boundary conditions. The following describes the Lagrangian approach used to derive the equations of motion for the active truss and the beams attached to it. A partial-state feedback control law is derived for this system based on a full-state feedback Linear Quadratic Regulator method. The analytical model is examined via numerical simulations and the results are compared to a similar experimental apparatus described herein. The results show that control of a flexible continua is possible with a free-free active truss.

  17. Missile flight control using active flexspar actuators

    NASA Astrophysics Data System (ADS)

    Barrett, Ronald M.; Gross, R. Steven; Brozoski, Fred

    1995-05-01

    A new type of subsonic missile flight control surface using piezoelectric flexspar actuators is presented. The flexspar design uses an aerodynamic shell which is pivoted at the quarter-chord about a graphite main spar. The shell is pitched up and down by a piezoelectric bender element which is rigidly attached to a base mount and allowed to rotate freely at the tip. The element curvature, shell pitch deflection and torsional stiffness are modeled using laminated plate theory. A one-third scale TOW 2B missile model was used as a demonstration platform. A static wing of the missile was replaced with an active flexspar wing. The 1' X 2.7' active flight control surface was powered by a bi-morph bender with 5-mil PZT-5H sheets. Bench and wind tunnel testing showed good correlation between theory and experiment and static pitch deflections in excess of +/- 14 degree(s). A natural frequency of 78.5 rad/s with a break frequency of 157 rad/s was measured. Wind tunnel tests revealed no flutter or divergence tendencies. Maximum changes in lift coefficient were measured at (Delta) CL equals +/- .73 which indicates that terminal and initial missile load factors may be increased by approximately 3.1 and 12.6 g's respectively, leading to a greatly reduced turn radius of only 2,400 ft.

  18. Egg yolks inhibit activation of NF-κB and expression of its target genes in adipocytes after partial delipidation

    PubMed Central

    Shen, Qiwen; Riedl, Ken M.; Cole, Rachel M.; Lehman, Christopher; Xu, Lu; Alder, Hansjuerg; Belury, Martha A.; Schwartz, Steven J.; Ziouzenkova, Ouliana

    2015-01-01

    How composition of egg yolk (EY) influences NF-κB, a key transcription pathway in inflammation, remains unclear. We performed partial delipidation of EY that removed 20–30% of cholesterol and triglycerides. The resulting polar and non-polar fractions were termed EY-P and EY-NP. NF-κB activation in response to EY from different suppliers and their fractions was examined in 3T3-L1 adipocytes using a NF-κB response element reporter assay and by analyzing expression of 248 inflammatory genes. Although EY-P and EY contained similar level of vitamins, carotenoids, and fatty acids, only delipidated EY-P fraction suppressed NF-κB via down-regulation of toll like receptor-2 and up-regulation of inhibitory toll interacting protein (Tollip) and lymphocyte antigen 96 (Ly96). Our data suggest that anti-inflammatory activity of lutein and retinol were blunted by non-polar lipids in EY likely via crosstalk between SREBP and NF-κB pathways in adipocytes. Thus, moderate delipidation may improve their beneficial properties of regular eggs. PMID:25620076

  19. A novel perovskite based catalyst with high selectivity and activity for partial oxidation of methane for fuel cell applications.

    PubMed

    Staniforth, J; Evans, S E; Good, O J; Darton, R J; Ormerod, R M

    2014-10-28

    Solid oxide fuel cells (SOFCs) have the potential to revolutionise the present fuel economy due to their higher fuel conversion efficiency compared with standard heat engines and the possibility of utilizing the heat produced in a combined heat and power system. One of the reasons they have yet to fulfil this potential is that the conventional anode material of choice, a nickel/yttria-stabilised zirconia cermet, requires a high temperature production process and under operating conditions is susceptible to carbon and sulphur poisoning. Perovskite-based materials have been proposed as potential anode materials for SOFCs due to their potentially high electronic conductivity and catalytic properties. One of the problems in realizing this potential has been their low catalytic activity towards methane reforming compared to conventional nickel based cermet materials. A nickel doped strontium zirconate material produced by low temperature hydrothermal synthesis is described which has high activity for methane reforming and high selectivity towards partial oxidation of methane as opposed to total oxidation products. Initial studies show a very low level of carbon formation which does not increase over time. PMID:25069597

  20. Cardiovascular protection and antioxidant activity of the extracts from the mycelia of Cordyceps sinensis act partially via adenosine receptors.

    PubMed

    Yan, Xiao-Feng; Zhang, Zhong-Miao; Yao, Hong-Yi; Guan, Yan; Zhu, Jian-Ping; Zhang, Lin-Hui; Jia, Yong-Liang; Wang, Ru-Wei

    2013-11-01

    Mycelia of cultured Cordyceps sinensis (CS) is one of the most common substitutes for natural CS and was approved for arrhythmia in China. However, the role of CS in ameliorating injury during ischemia-reperfusion (I/R) is still unclear. We examined effects of extracts from CS on I/R and investigated the possible mechanisms. Post-ischemic coronary perfusion pressure, ventricular function, and coronary flow were measured using the Langendorff mouse heart model. Oxidative stress of cardiac homogenates was performed using an ELISA. Our results indicate that CS affords cardioprotection possibly through enhanced adenosine receptor activation. Cardioprotection was demonstrated by reduced post-ischemic diastolic dysfunction and improved recovery of pressure development and coronary flow. Treatment with CS largely abrogates oxidative stress and damage in glucose- or pyruvate-perfused hearts. Importantly, observed reductions in oxidative stress [glutathione disulfide (GSSG)]/[GSSG + glutathione] and [malondialdehyde (MDA)]/[superoxide dismutase + MDA] ratios as well as the resultant damage upon CS treatment correlate with functional markers of post-ischemic myocardial outcome. These effects of CS were partially blocked by 8-ρ-sulfophenyltheophylline, an adenosine receptor antagonist. Our results demonstrate a suppressive role of CS in ischemic contracture. Meanwhile, the results also suggest pre-ischemic adenosine receptor activation may be involved in reducing contracture in hearts pretreated with CS. PMID:23192916

  1. Acetyl-L-carnitine restores choline acetyltransferase activity in the hippocampus of rats with partial unilateral fimbria-fornix transection.

    PubMed

    Piovesan, P; Quatrini, G; Pacifici, L; Taglialatela, G; Angelucci, L

    1995-02-01

    Transection of the fimbria-fornix bundle in adult rats results in degeneration of the septohippocampal cholinergic pathway, reminiscent of that occurring in aging as well as Alzheimer disease. We report here a study of the effect of a treatment with acetyl-L-carnitine (ALCAR) in three-month-old Fischer 344 rats bearing a partial unilateral fimbria-fornix transection. ALCAR is known to ameliorate some morphological and functional disturbances in the aged central nervous system (CNS). We used choline acetyltransferase (ChAT) and acetyl cholinesterase (AChE) as markers of central cholinergic function, and nerve growth factor (NGF) levels as indicative of the trophic regulation of the medio-septal cholinergic system. ChAT and AChE activities were significantly reduced in the hippocampus (HIPP) ipsilateral to the lesion as compared to the contralateral one, while no changes were observed in the septum (SPT), nucleus basalis magnocellularis (NBM) or frontal cortex (FCX). ALCAR treatment restored ChAT activity in the ipsilateral HIPP, while AChE levels were not different from those of untreated animals, and did not affect NGF content in either SPT or HIPP. PMID:7793306

  2. Polymeric surfaces exhibiting photocatalytic activity and controlled anisotropic wettability

    NASA Astrophysics Data System (ADS)

    Anastasiadis, Spiros H.; Frysali, Melani A.; Papoutsakis, Lampros; Kenanakis, George; Stratakis, Emmanuel; Vamvakaki, Maria; Mountrichas, Grigoris; Pispas, Stergios

    2015-03-01

    In this work we focus on surfaces, which exhibit controlled, switchable wettability in response to one or more external stimuli as well as photocatalytic activity. For this we are inspired from nature to produce surfaces with a dual-scale hierarchical roughness and combine them with the appropriate inorganic and/or polymer coating. The combination of the hierarchical surface with a ZnO coating and a pH- or temperature-responsive polymer results in efficient photo-active properties as well as reversible superhydrophobic / superhydrophilic surfaces. Furthermore, we fabricate surfaces with unidirectional wettability variation. Overall, such complex surfaces require advanced design, combining hierarchically structured surfaces with suitable polymeric materials. Acknowledgment: This research was partially supported by the European Union (European Social Fund, ESF) and Greek national funds through the ``ARISTEIA II'' Action (SMART-SURF) of the Operational Programme ``Education and Lifelong Learning,'' NSRF 2007-2013, via the General Secretariat for Research & Technology, Ministry of Education and Religious Affairs, Greece.

  3. QTL meta-analysis provides a comprehensive view of loci controlling partial resistance to Aphanomyces euteiches in four sources of resistance in pea

    Technology Transfer Automated Retrieval System (TEKTRAN)

    More knowledge about diversity of Quantitative Trait Loci (QTL) controlling polygenic disease resistance in natural genetic variation of crop species is required for durably improving plant genetic resistances to pathogens. Polygenic partial resistance to Aphanomyces root rot, due to Aphanomcyces eu...

  4. New consistent QTL in pea associated with partial resistance to Aphanomyces euteiches in multiple field and controlled environments from France and the United States

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Partial resistances, often controlled by QTL (Quantitative Trait Loci), are considered to be more durable than monogenic resistances. Prior to develop efficient breeding programs for polygenic resistance to pathogens, a higher understanding of genetic diversity and stability of resistance QTL in pla...

  5. Deciphering interference control in adults with ADHD by using distribution analyses and electromyographic activity.

    PubMed

    Suarez, Isabel; Burle, B; Tobon, C; Pineda, D; Lopera, F; Hasbroucq, T; Casini, L

    2015-07-01

    A deficit in "interference control" is commonly found in adults with Attention Deficit Hyperactivity Disorder (ADHD). This has mainly been interpreted as difficulties in inhibiting inappropriate responses. However, interference control involves processes other than simply the ability to inhibit. Consequently, we used sophisticated analysis to decipher the additional processes of interference control in these patients. We compared interference control between 16 adults with ADHD and 15 control adults performing a Simon task. In most studies, performance is generally reported in terms of mean error rates and reaction times (RTs). However, here we used distribution analyses of behavioral data, complemented by analyses of electromyographic (EMG) activity. This allowed us to better quantify the control of interference, specifically the part that remains hidden when pure correct trials are not distinguished from partial errors. Partial errors correspond to sub-threshold EMG bursts induced by incorrect responses that immediately precede a correct response. Moreover, besides "online" control, we also investigated cognitive control effects manifesting across consecutive trials. The main findings were that adults with ADHD were slower and showed a larger interference effect in comparison to controls. However, the data revealed that the larger interference effect was due neither to higher impulse expression, nor to a deficit in inhibition but that these patients presented a larger interference effect than the controls after congruent trials. We propose and discuss the hypothesis that the interference control deficit found in adults with ADHD is secondary to impairments in sustained attention. PMID:26057599

  6. Controlled partial-exfoliation of graphite foil and integration with MnO2 nanosheets for electrochemical capacitors

    NASA Astrophysics Data System (ADS)

    Song, Yu; Feng, Dong-Yang; Liu, Tian-Yu; Li, Yat; Liu, Xiao-Xia

    2015-02-01

    Here we demonstrate a controlled two-step partial exfoliation method to synthesize functionalized exfoliated graphite substrates. Ultrathin and functionalized graphene sheets anchoring on the graphite provide a large conductive surface area for loading pseudo-capacitive MnO2 nanosheets. The functionalized exfoliated graphite/MnO2 electrode achieved an excellent areal capacitance of 244 mF cm-2, corresponding to an estimated MnO2 based gravimetric capacitance of 1061 F g-1, which is just slightly lower than its theoretical value of 1110 F g-1. More importantly, the seamless integration of graphene sheets and the graphite substrate minimizes the contact resistance, and substantially improves the rate capability of pseudo-capacitive materials. The electrode retained 44.8% of its capacitance when the charging current density increased 50 times from 0.23 to 11.5 mA cm-2. This novel functionalized exfoliated graphite substrate serves as a promising supporting material that could address the relatively low electrical conductivity of various pseudo-capacitive materials, and increase the mass loading and rate capability of pseudo-capacitors.Here we demonstrate a controlled two-step partial exfoliation method to synthesize functionalized exfoliated graphite substrates. Ultrathin and functionalized graphene sheets anchoring on the graphite provide a large conductive surface area for loading pseudo-capacitive MnO2 nanosheets. The functionalized exfoliated graphite/MnO2 electrode achieved an excellent areal capacitance of 244 mF cm-2, corresponding to an estimated MnO2 based gravimetric capacitance of 1061 F g-1, which is just slightly lower than its theoretical value of 1110 F g-1. More importantly, the seamless integration of graphene sheets and the graphite substrate minimizes the contact resistance, and substantially improves the rate capability of pseudo-capacitive materials. The electrode retained 44.8% of its capacitance when the charging current density increased 50

  7. Cellular steatosis in ethanol oxidizing-HepG2 cells is partially controlled by the transcription factor, early growth response-1

    PubMed Central

    Thomes, Paul G.; Osna, Natalia A.; Davis, John S.; Donohue, Terrence M.

    2012-01-01

    Recent studies have shown that the transcription factor early growth response-1 (Egr-1) regulates ethanol-induced fatty liver. However, the mechanism(s) through which ethanol oxidation controls Egr-1 is unknown. Here, using recombinant hepatoma (HepG2; VL-17A) cells that metabolize ethanol, we show that alcohol dehydrogenase catalysis of ethanol oxidation and subsequent acetaldehyde production controls Egr-1 expression. Further, the induction of Egr-1 enhances expression of other steatosis-related genes, resulting in triglyceride accumulation. Ethanol exposure increased Egr-1 promoter activity, messenger RNA and Egr-1 protein levels in VL-17A cells. Elevated Egr-1 protein was sustained by an ethanol-induced decrease in proteasome activity, thereby stabilizing the Egr-1 protein. Egr-1 induction depended on ethanol oxidation, as it was prevented when ethanol oxidation was blocked. Ethanol exposure induced Egr-1 and triglyceride accumulation only in alcohol dehydrogenase-expressing cells that produced acetaldehyde. Such induction did not occur in parental, non-metabolizing HepG2 cells or in cells that express only cytochrome P450 2E1. However, direct exposure of HepG2 cells to acetaldehyde induced both Egr-1 protein and triglycerides. Egr-1 over-expression elevated triglyceride levels, which were augmented by ethanol exposure. However, these triglyceride levels did not exceed those in ethanol-exposed cells that had normal Egr-1 expression. Conversely, Egr-1 knockdown by siRNA only partially blocked ethanol-induced triglyceride accumulation and was associated not only with lower Egr-1 expression but also attenuation of SREBP1c and TNF-α mRNAs. Double knockdown of both Egr-1 and SREBP-1c abolished ethanol-elicited steatosis. Collectively, our findings provide important new insights into the temporal regulation by ethanol oxidation of Egr-1 and cellular steatosis. PMID:23103837

  8. Amplitude Scaling of Active Separation Control

    NASA Technical Reports Server (NTRS)

    Stalnov, Oksana; Seifert, Avraham

    2010-01-01

    Three existing and two new excitation magnitude scaling options for active separation control at Reynolds numbers below one Million. The physical background for the scaling options was discussed and their relevance was evaluated using two different sets of experimental data. For F+ approx. 1, 2D excitation: a) The traditional VR and C(mu) - do not scale the data. b) Only the Re*C(mu) is valid. This conclusion is also limited for positive lift increment.. For F+ > 10, 3D excitation, the Re corrected C(mu), the St corrected velocity ratio and the vorticity flux coefficient, all scale the amplitudes equally well. Therefore, the Reynolds weighted C(mu) is the preferred choice, relevant to both excitation modes. Incidence also considered, using Ue from local Cp.

  9. Ribosome-dependent activation of stringent control.

    PubMed

    Brown, Alan; Fernández, Israel S; Gordiyenko, Yuliya; Ramakrishnan, V

    2016-06-01

    In order to survive, bacteria continually sense, and respond to, environmental fluctuations. Stringent control represents a key bacterial stress response to nutrient starvation that leads to rapid and comprehensive reprogramming of metabolic and transcriptional patterns. In general, transcription of genes for growth and proliferation is downregulated, while those important for survival and virulence are upregulated. Amino acid starvation is sensed by depletion of the aminoacylated tRNA pools, and this results in accumulation of ribosomes stalled with non-aminoacylated (uncharged) tRNA in the ribosomal A site. RelA is recruited to stalled ribosomes and activated to synthesize a hyperphosphorylated guanosine analogue, (p)ppGpp, which acts as a pleiotropic secondary messenger. However, structural information about how RelA recognizes stalled ribosomes and discriminates against aminoacylated tRNAs is missing. Here we present the cryo-electron microscopy structure of RelA bound to the bacterial ribosome stalled with uncharged tRNA. The structure reveals that RelA utilizes a distinct binding site compared to the translational factors, with a multi-domain architecture that wraps around a highly distorted A-site tRNA. The TGS (ThrRS, GTPase and SpoT) domain of RelA binds the CCA tail to orient the free 3' hydroxyl group of the terminal adenosine towards a β-strand, such that an aminoacylated tRNA at this position would be sterically precluded. The structure supports a model in which association of RelA with the ribosome suppresses auto-inhibition to activate synthesis of (p)ppGpp and initiate the stringent response. Since stringent control is responsible for the survival of pathogenic bacteria under stress conditions, and contributes to chronic infections and antibiotic tolerance, RelA represents a good target for the development of novel antibacterial therapeutics. PMID:27279228

  10. Active Control of Wind Tunnel Noise

    NASA Technical Reports Server (NTRS)

    Hollis, Patrick (Principal Investigator)

    1991-01-01

    The need for an adaptive active control system was realized, since a wind tunnel is subjected to variations in air velocity, temperature, air turbulence, and some other factors such as nonlinearity. Among many adaptive algorithms, the Least Mean Squares (LMS) algorithm, which is the simplest one, has been used in an Active Noise Control (ANC) system by some researchers. However, Eriksson's results, Eriksson (1985), showed instability in the ANC system with an ER filter for random noise input. The Restricted Least Squares (RLS) algorithm, although computationally more complex than the LMS algorithm, has better convergence and stability properties. The ANC system in the present work was simulated by using an FIR filter with an RLS algorithm for different inputs and for a number of plant models. Simulation results for the ANC system with acoustic feedback showed better robustness when used with the RLS algorithm than with the LMS algorithm for all types of inputs. Overall attenuation in the frequency domain was better in the case of the RLS adaptive algorithm. Simulation results with a more realistic plant model and an RLS adaptive algorithm showed a slower convergence rate than the case with an acoustic plant as a delay plant. However, the attenuation properties were satisfactory for the simulated system with the modified plant. The effect of filter length on the rate of convergence and attenuation was studied. It was found that the rate of convergence decreases with increase in filter length, whereas the attenuation increases with increase in filter length. The final design of the ANC system was simulated and found to have a reasonable convergence rate and good attenuation properties for an input containing discrete frequencies and random noise.

  11. Missile flight control using active flexspar actuators

    NASA Astrophysics Data System (ADS)

    Barrett, Ron; Gross, R. Steven; Brozoski, Fred

    1996-04-01

    A new type of subsonic missile flight control surface using piezoelectric flexspar actuators is presented. The flexspar design uses an aerodynamic shell which is pivoted at the quarter-chord about a graphite main spar. The shell is pitched up and down by a piezoelectric bender element which is rigidly attached to a base mount and allowed to rotate freely at the tip. The element curvature, shell pitch deflection and torsional stiffness are modeled using laminated plate theory. A one-third scale TOW 2B missile model was used as a demonstration platform. A static wing of the missile was replaced with an active flexspar wing. The 1 in 0964-1726/5/2/002/img1 2.7 in active flight control surface was powered by a bimorph bender with 5 mil PZT-5H sheets. Bench and wind tunnel testing showed good correlation between theory and experiment and static pitch deflections in excess of 0964-1726/5/2/002/img2. A natural frequency of 78.5 rad 0964-1726/5/2/002/img3 with a break frequency of 157 rad 0964-1726/5/2/002/img3 was measured. Wind tunnel tests revealed no flutter or divergence tendencies. Maximum changes in lift coefficient were measured at 0964-1726/5/2/002/img5 which indicates that terminal and initial missile load factors may be increased by approximately 3.1 and 12.6 g respectively, leading to a greatly reduced turn radius of only 2400 ft.

  12. Active Shielding and Control of Environmental Noise

    NASA Technical Reports Server (NTRS)

    Tsynkov, S. V.

    2001-01-01

    In the framework of the research project supported by NASA under grant # NAG-1-01064, we have studied the mathematical aspects of the problem of active control of sound, i.e., time-harmonic acoustic disturbances. The foundations of the methodology are described in our paper [1]. Unlike. many other existing techniques, the approach of [1] provides for the exact volumetric cancellation of the unwanted noise on a given predetermined region airspace, while leaving unaltered those components of the total acoustic field that are deemed as friendly. The key finding of the work is that for eliminating the unwanted component of the acoustic field in a given area, one needs to know relatively little; in particular, neither the locations nor structure nor strength of the exterior noise sources need to be known. Likewise, there is no need to know the volumetric properties of the supporting medium across which the acoustic signals propagate, except, maybe, in a narrow area of space near the perimeter of the protected region. The controls are built based solely on the measurements performed on the perimeter of the domain to be shielded; moreover, the controls themselves (i.e., additional sources) are concentrated also only on or near this perimeter. Perhaps as important, the measured quantities can refer to the total acoustic field rather than to its unwanted component only, and the methodology can automatically distinguish between the two. In [1], we have constructed the general solution for controls. The apparatus used for deriving this general solution is closely connected to the concepts of generalized potentials and boundary projections of Calderon's type. For a given total wave field, the application of a Calderon's projection allows one to definitively tell between its incoming and outgoing components with respect to a particular domain of interest, which may have arbitrary shape. Then, the controls are designed so that they suppress the incoming component for the domain

  13. Actively controlled thin-shell space optics

    NASA Astrophysics Data System (ADS)

    Denoyer, Keith K.; Flint, Eric M.; Main, John A.; Lindler, Jason E.

    2003-08-01

    Increasingly, scientific and military missions require the use of space-based optical systems. For example, new capabilities are required for imaging terrestrial like planets, for surveillance, and for directed energy applications. Given the difficulties in producing and launching large optics, it is doubtful that refinements of conventional technology will meet future needs, particularly in a cost-effective manner. To meet this need, recent research has been investigating the feasibility of a new class of ultra-lightweight think-skin optical elements that combine recent advances in lightweight thermally formed materials, active materials, and novel sensing and control architectures. If successful, the approach may lead to an order of magnitude reduction in space optics areal density, improved large scale manufacturing capability, and dramatic reductions in manufacturing and launch costs. In a recent effort, a one meter thin-film mirror like structure was fabricated. This paper provides an overview of tools used to model and simulate this structure as well as results from structural dynamic testing. In addition, progress in the area of non-contact global shape control using smart materials is presented.

  14. High performance composites with active stiffness control.

    PubMed

    Tridech, Charnwit; Maples, Henry A; Robinson, Paul; Bismarck, Alexander

    2013-09-25

    High performance carbon fiber reinforced composites with controllable stiffness could revolutionize the use of composite materials in structural applications. Here we describe a structural material, which has a stiffness that can be actively controlled on demand. Such a material could have applications in morphing wings or deployable structures. A carbon fiber reinforced-epoxy composite is described that can undergo an 88% reduction in flexural stiffness at elevated temperatures and fully recover when cooled, with no discernible damage or loss in properties. Once the stiffness has been reduced, the required deformations can be achieved at much lower actuation forces. For this proof-of-concept study a thin polyacrylamide (PAAm) layer was electrocoated onto carbon fibers that were then embedded into an epoxy matrix via resin infusion. Heating the PAAm coating above its glass transition temperature caused it to soften and allowed the fibers to slide within the matrix. To produce the stiffness change the carbon fibers were used as resistance heating elements by passing a current through them. When the PAAm coating had softened, the ability of the interphase to transfer load to the fibers was significantly reduced, greatly lowering the flexural stiffness of the composite. By changing the moisture content in PAAm fiber coating, the temperature at which the PAAm softens and the composites undergo a reduction in stiffness can be tuned. PMID:23978266

  15. Development of additives in negative active-material to suppress sulfation during high-rate partial-state-of-charge operation of lead-acid batteries

    NASA Astrophysics Data System (ADS)

    Sawai, Ken; Funato, Takayuki; Watanabe, Masashi; Wada, Hidetoshi; Nakamura, Kenji; Shiomi, Masaaki; Osumi, Shigeharu

    Additives in the negative active-material of lead-acid batteries were examined to determine whether they could prevent progressive accumulation of lead sulfate (PbSO 4) in negative plates during high-rate partial-state-of-charge (HRPSoC) operation. This phenomenon is caused by progressive growth of PbSO 4 particles and a lack of conductive paths near these PbSO 4 particles. Barium sulfate (BaSO 4) particles in various sizes and synthetic lignin were added to the negative active-material to control PbSO 4 particle size during HRPSoC cycle-life. Some types of carbon fibres were also added to form conductive paths around the PbSO 4 particles. Synthetic lignin was found to be the most effective additive for improving battery life in HRPSoC cycle-life tests, whereas the other factors such as BaSO 4 size or carbon fibre extended less influence. The growth rate of PbSO 4 particles per cycle was much lower in a cell with synthetic lignin than in a cell with natural lignin.

  16. Inter-costal Liver Ablation Under Real Time MR-Thermometry With Partial Activation Of A HIFU Phased Array Transducer

    NASA Astrophysics Data System (ADS)

    Quesson, Bruno; Merle, Mathilde; Köhler, Max; Mougenot, Charles; Roujol, Sebastien; de Senneville, Baudouin Denis; Moonen, Chrit

    2010-03-01

    HIFU ablation of tumours located inside the liver is hampered by the rib cage, which partially obstructs the beam path and may create adverse effects such as skin burns. This study presents a method for selectively deactivating the transducer elements causing undesired temperature increases near the bones. A manual segmentation of the bones visualized on 3D anatomical MR images acquired prior to sonication was performed to identify the beam obstruction. The resulting mask was projected (ray tracing starting from the focal point) on the transducer and elements with more than 50% obstruction of their active surface were deactivated. The effectiveness of the method for HIFU ablations is demonstrated ex vivo and in vivo in the liver of pigs with real-time MR thermometry, using the proton resonant frequency (PRF) method. For both ex vivo and in vivo experiments, the temperature increase near the bones was significantly reduced when the elements located in front of the ribs were deactivated. The temperature evolution at the focal point were similar, indicative of the absence of loss of heating efficacy when the elements were deactivated. This method is simple, rapid and reliable and allows to perform intercostal MRgHIFU ablation of the liver while sparing the ribs.

  17. Highly efficient active optical interconnect incorporating a partially chlorinated ribbon POF in conjunction with a visible VCSEL.

    PubMed

    Lee, Hak-Soon; Lee, Sang-Shin; Kim, Bong-Seok; Son, Yung-Sung

    2014-05-19

    A low-loss 4-ch active optical interconnect (AOI) enabling passive alignment was proposed and built resorting to a transmitter (Tx) incorporating a red 680-nm VCSEL, which is linked to a receiver (Rx) module via a partially chlorinated ribbon POF. The POF was observed to exhibit an extremely low loss of ~0.24 dB/m at λ = 680 nm, in comparison to ~1.29 dB/m at λ = 850 nm, and a large numerical aperture of ~0.42. Both the Tx and Rx, which taps into a beam router based on collimated beam optics involving a pair of spherical lenses, were meant to be substantially alignment tolerant and compact. The achieved tolerance for the constructed modules was beyond 40 μm in terms of the positioning of VCSEL and photodetector. The proposed AOI was completed by linking the Tx with the Rx via a 3-m long ribbon POF, incurring a transmission loss of as small as 3.2 dB. The AOI was practically assessed in terms of a high-speed data transmission over a wide range of temperatures and then exploited to convey full HD video signals. PMID:24921299

  18. Influence of fibrinogen degradation products on thrombin time, activated partial thromboplastin time and prothrombin time of canine plasma.

    PubMed

    Mischke, R; Wolling, H

    2000-01-01

    To investigate how thrombin time, activated partial thromboplastin time (APTT) and prothrombin time are influenced by fibrinogen degradation products (FDP), different concentrations (0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.8 and 1.0 mg/ml) of the purified FDP X, Y, D and E were added to the plasma of healthy dogs. If fragment Y was added to the plasma a considerable inhibitory effect could be demonstrated for all three test systems. A significant prolongation (p < 0.05) was found for concentrations of > or =0.1 mg/ml (thrombin time, APTT) and > or =0.2 mg/ml (prothrombin time). With FDP Y concentrations from >0.185 mg/ml (prothrombin time) to >0.24 mg/ml (APTT) coagulation time was prolonged beyond the respective reference range. As regards the other fragments, a comparable inhibitory effect could only be shown for fragment X added to the thrombin time test system. This effect can most probably be explained by the competition of the FDP X and fibrinogen for the fibrinogen binding sites of thrombin, rather than by a fibrin polymerization disorder. The results demonstrate that for plasma with normal fibrinogen concentration the group tests are only prolonged beyond the reference range at FDP concentrations very rarely found in spontaneous hyperfibrinolysis. PMID:11014962

  19. New mutations of Saccharomyces cerevisiae that partially relieve both glucose and galactose repression activate the protein kinase Snf1.

    PubMed

    Rodríguez, Cristina; Sanz, Pascual; Gancedo, Carlos

    2003-03-01

    We isolated from Saccharomyces cerevisiae two mutants, esc1-1 and ESC3-1, in which genes FBP1, ICL1 or GDH2 were partially derepressed during growth in glucose or galactose. The isolation was done starting with a triple mutant pyc1 pyc2 mth1 unable to grow in glucose-ammonium medium and selecting for mutants able to grow in the non-permissive medium. HXT1 and HXT2 which encode glucose transporters were expressed at high glucose concentrations in both esc1-1 and ESC3-1 mutants, while derepression of invertase at low glucose concentrations was impaired. REG1, cloned as a suppressor of ESC3-1, was not allelic to ESC3-1. Two-hybrid analysis showed an increased interaction of the protein kinase Snf1 with Snf4 in the ESC3-1 mutant; this was not due to mutations in SNF1 or SNF4. ESC3-1 did not bypass the requirement of Snf1 for derepression. We hypothesize that ESC3-1 either facilitates activation of Snf1 or interferes with its glucose-dependent inactivation. PMID:12702249

  20. Antibacterial activity and mechanical properties of partially hydrolyzed sago starch-alginate edible film containing lemongrass oil.

    PubMed

    Maizura, M; Fazilah, A; Norziah, M H; Karim, A A

    2007-08-01

    Edible films were prepared from a mixture of partially hydrolyzed sago starch and alginate (SA). Lemongrass oil (0.1% to 0.4%, v/w) and glycerol (0% and 20%, w/w) were incorporated in the films to act as natural antimicrobial agent and plasticizer, respectively. The films were characterized for antimicrobial activity, water vapor permeability (WVP), tensile strength (TS), percent elongation at break (%E), and water solubility (WS). Fourier transform infrared (FTIR) spectroscopy was conducted to determine functional group interactions between the matrix and lemongrass oil. The zone of inhibition was increased significantly (P < 0.05) by addition of lemongrass oil at all levels in the presence and the absence of glycerol. This indicates that the film containing lemongrass oil was effective against Escherichia coli O157:H7 at all levels. In the absence of glycerol, the tensile strength of film decreased as the oil content increased, but there was no significant (P > 0.05) difference in percent elongation. The percent elongation at break and WVP values for film with 20% glycerol was found to be increased significantly (P < 0.05) with an increase in lemongrass oil content. Addition of lemongrass oil did not have any interaction with the functional groups of films as measured by FTIR. PMID:17995673

  1. Crustal differentiation due to partial melting of granitic rocks in an active continental margin, the Ryoke Belt, Southwest Japan

    NASA Astrophysics Data System (ADS)

    Akasaki, Eri; Owada, Masaaki; Kamei, Atsushi

    2015-08-01

    The continental margin of Pacific Asia is dominated by the voluminous Cretaceous to Paleogene granitic rocks. The Ryoke granitoids that occur in the Ryoke Belt in the Southwest Japan Arc are divided into the older and younger granites. The high-K Kibe Granite represents the younger granitic intrusion and is exposed in the Yanai area in the western part of Ryoke Belt. The Kibe Granite is associated with the coeval Himurodake Quartz Diorite and their intrusive age is 91 Ma. However, the Gamano-Obatake Granodiorite, the older granite, intruded the host Ryoke gneisses at 95 Ma. The Gamano-Obatake Granodiorite is characterized by the localized development of migmatitic structure attributed to the intrusion of the Himurodake Quartz Diorite into the granodiorite. Leucocratic pools and patches occur in the granodiorite in the vicinity of the quartz diorite. The Sr and Nd isotopic compositions of the Gamano-Obatake Granodiorite corrected to 91 Ma are plotted within those of the Kibe Granite. Geochemical modeling suggests that partial melting took place in the Gamano-Obatake Granodiorite and resulted in the formation of the Kibe Granite magma. The Himurodake Quartz Diorite is believed to be a heat source for this event. This can be considered as an essential process for the formation of the evolved younger Ryoke granite and for the crustal differentiation in the active continental margin.

  2. Effect of temperature on AOB activity of a partial nitritation SBR treating landfill leachate with extremely high nitrogen concentration.

    PubMed

    Gabarró, J; Ganigué, R; Gich, F; Ruscalleda, M; Balaguer, M D; Colprim, J

    2012-12-01

    This study investigates the effects of temperature on ammonia oxidizing bacteria activity in a partial nitritation (PN) sequencing batch reactor. Stable PN was achieved in a 250 L SBR with a minimum operating volume of 111L treating mature landfill leachate containing an ammonium concentration of around 6000 mg N-NH(4)(+)L(-1) at both 25 and 35 °C. A suitable influent to feed an anammox reactor was achieved in both cases. A kinetic model was applied to study the influence of free ammonia (FA), the free nitrous acid (FNA) inhibition, and the inorganic carbon (IC) limitation. NH(4)(+) and NO(2)(-) concentrations were similar at 25 and 35 °C experiments (about 2500 mg N-NH(4)(+)L(-1) and 3500 mg N-NO(2)(-)L(-1)), FA and FNA concentrations differed due to the strong temperature dependence. FNA was the main source of inhibition at 25 °C, while at 35 °C combined FA and FNA inhibition occurred. DGGE results demonstrated that PN-SBR sludge was enriched on the same AOB phylotypes in both experiments. PMID:23079415

  3. Robust controllers for the Middeck Active Control Experiment using Popov controller synthesis

    NASA Technical Reports Server (NTRS)

    How, Jonathan P.; Hall, Steven R.

    1993-01-01

    Recent work in robust control with real parameter uncertainties has focused on absolute stability and its connections to real mu theory. In particular, the research has investigated the Popov stability criterion and its associated Lur'e-Postnikov Liapunov functions. State space representations of this Popov stability analysis tests are included in an H2 design formulation to provide a powerful technique for robust controller synthesis. This synthesis approach uses a state space optimization procedure to design controllers that minimize an overbound of an H2 cost functional and satisfy stability analysis tests based on the Popov multiplier. The controller and stability multiplier coefficients are optimized simultaneously, which avoids the iteration and curve-fitting procedures required by the D-K algorithm of mu synthesis. While previous work has demonstrated this synthesis approach on benchmark control problems, the purpose of this paper is to use Popov controller synthesis to design robust compensators for the Middeck Active Control Experiment (MACE).

  4. Determining the effect of storage conditions on prothrombin time, activated partial thromboplastin time and fibrinogen concentration in rat plasma samples.

    PubMed

    Goyal, Vinod Kumar; Kakade, Somesh; Pandey, Santosh Kumar; Gothi, Anil Kalidas; Nirogi, Ramakrishna

    2015-10-01

    Coagulation parameters are usually included in clinical and preclinical safety studies to evaluate the effect of xenobiotics on the extrinsic or intrinsic pathways of coagulation. The analysis is generally performed at the time of terminal sacrifice where many activities are scheduled. Chances of delay in analysis are likely particularly when blood is collected for coagulation via the abdominal vena cava. This experiment was planned to assess the variations in coagulation parameters caused by delay in analysis as well as by storage conditions. Blood was collected from the posterior vena cava under isoflurane anesthesia, and the plasma was separated immediately. Coagulation parameters were evaluated at 0, 6, 24 and 48 h from the plasma stored at room temperature, as well as plasma stored under refrigerated and freezing conditions. Stability of the analytes in blood was also evaluated under refrigerated conditions for 6 h. All parameters were analyzed using a semi-automated coagulometer. Prothrombin time (PT) was stable under all three storage conditions for up to 6 h. Although statistically significant differences were observed for activated partial thromboplastin time (APTT) at room and refrigeration temperatures for up to 6 h, the difference was clinically non-relevant. Fibrinogen was found to be the most stable parameter that showed consistency in results even up to 48 h under all three storage conditions. Plasma for PT can be stored and analyzed without any significant changes for up to 6 h from the actual blood collection, while fibrinogen level testing can be extended for up to 48 h after collection under any storage condition. For reliable APTT results, plasma samples should be run immediately after collection. PMID:26206586

  5. Open architecture controller activities in Technology Enabling Agile Manufacturing (TEAM)

    NASA Astrophysics Data System (ADS)

    McCue, Howard K.

    1997-01-01

    As part of its manufacturing initiative, TEAM is actively involved in open architecture controller activities. WIthin the TEAM community of members, TEAM is developing an open architecture controller requirements document and an open architecture controller application programming interface document. In addition, TEAM is also evaluating early open architecture controllers in a shop floor environment.

  6. Homeopathy for Depression - DEP-HOM: study protocol for a randomized, partially double-blind, placebo controlled, four armed study

    PubMed Central

    2011-01-01

    Background Homeopathy is often sought by patients with depression. In classical homeopathy, the treatment consists of two main elements: the case history and the prescription of an individually selected homeopathic remedy. Previous data suggest that individualized homeopathic Q-potencies were not inferior to the antidepressant fluoxetine in a sample of patients with moderate to severe depression. However, the question remains whether individualized homeopathic Q-potencies and/or the type of the homeopathic case history have a specific therapeutical effect in acute depression as this has not yet been investigated. The study aims to assess the two components of individualized homeopathic treatment for acute depression, i.e., to investigate the specific effect of individualized Q-potencies versus placebo and to investigate the effect of different approaches to the homeopathic case history. Methods/Design A randomized, partially double-blind, placebo-controlled, four-armed trial using a 2 × 2 factorial design with a six-week study duration per patient will be performed. 228 patients diagnosed with major depression (moderate episode) by a psychiatrist will be included. The primary endpoint is the total score on the 17-item Hamilton Depression Rating Scale after six weeks. Secondary end points are: Hamilton Depression Rating Scale total score after two and four weeks; response and remission rates, Beck Depression inventory total score, quality of life and safety at two, four and six weeks. Statistical analyses will be by intention-to-treat. The main endpoint will be analysed by a two-factorial analysis of covariance. Within this model generalized estimation equations will be used to estimate differences between verum and placebo, and between both types of case history. Discussion For the first time this study evaluates both the specific effect of homeopathic medicines and of a homeopathic case taking in patients with depression. It is an attempt to deal with the

  7. Homeopathy for Depression: A Randomized, Partially Double-Blind, Placebo-Controlled, Four-Armed Study (DEP-HOM)

    PubMed Central

    Adler, Ubiratan C.; Krüger, Stephanie; Teut, Michael; Lüdtke, Rainer; Schützler, Lena; Martins, Friederike; Willich, Stefan N.; Linde, Klaus; Witt, Claudia M.

    2013-01-01

    Background The specific clinical benefit of the homeopathic consultation and of homeopathic remedies in patients with depression has not yet been investigated. Aims To investigate the 1) specific effect of individualized homeopathic Q-potencies compared to placebo and 2) the effect of an extensive homeopathic case taking (case history I) compared to a shorter, rather conventional one (case history II) in the treatment of acute major depression (moderate episode) after six weeks. Methods A randomized, partially double-blind, placebo-controlled, four-armed trial using a 2×2 factorial design with a six-week study duration per patient was performed. Results A total of 44 from 228 planned patients were randomized (2∶1∶2∶1 randomization: 16 homeopathic Q-potencies/case history I, 7 placebo/case history I, 14 homeopathic Q-potencies/case history II, 7 placebo/case history II). Because of recruitment problems, the study was terminated prior to full recruitment, and was underpowered for the preplanned confirmatory hypothesis testing. Exploratory data analyses showed heterogeneous and inconclusive results with large variance in the sample. The mean difference for the Hamilton-D after 6 weeks was 2.0 (95%CI −1.2;5.2) for Q-potencies vs. placebo and −3.1 (−5.9;−0.2) for case history I vs. case history II. Overall, no consistent or clinically relevant results across all outcomes between homeopathic Q-potencies versus placebo and homeopathic versus conventional case taking were observed. The frequency of adverse events was comparable for all groups. Conclusions Although our results are inconclusive, given that recruitment into this trial was very difficult and we had to terminate early, we cannot recommend undertaking a further trial addressing this question in a similar setting. Prof. Dr. Claudia Witt had full access to all the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis. Trial registration

  8. Differential pathway coupling efficiency of the activated insulin receptor drives signaling selectivity by XMetA, an allosteric partial agonist antibody

    Technology Transfer Automated Retrieval System (TEKTRAN)

    XMetA, an anti-insulin receptor (IR) monoclonal antibody, is an allosteric partial agonist of the IR. We have previously reported that XMetA activates the “metabolic-biased” Akt kinase signaling pathway while having little or no effect on the “mitogenic” MAPK signaling pathwayof ERK 1/2. To inves...

  9. Characterization of CM572, a Selective Irreversible Partial Agonist of the Sigma-2 Receptor with Antitumor Activity.

    PubMed

    Nicholson, Hilary; Comeau, Anthony; Mesangeau, Christophe; McCurdy, Christopher R; Bowen, Wayne D

    2015-08-01

    The sigma-2 receptors are promising therapeutic targets because of their significant upregulation in tumor cells compared with normal tissue. Here, we characterize CM572 [3-(4-(4-(4-fluorophenyl)piperazin-1-yl)butyl)-6-isothiocyanatobenzo[d]oxazol-2(3H)-one] (sigma-1 Ki ≥ 10 µM, sigma-2 Ki = 14.6 ± 6.9 nM), a novel isothiocyanate derivative of the putative sigma-2 antagonist, SN79 [6-acetyl-3-(4-(4-(4-fluorophenyl)piperazin-1-yl)butyl)benzo[d]oxazol-2(3H)-one]. CM572 bound irreversibly to sigma-2 receptors by virtue of the isothiocyanate moiety but not to sigma-1. Studies in human SK-N-SH neuroblastoma cells revealed that CM572 induced an immediate dose-dependent increase in cytosolic calcium concentration. A 24-hour treatment of SK-N-SH cells with CM572 induced dose-dependent cell death, with an EC50 = 7.6 ± 1.7 µM. This effect was sustained over 24 hours even after a 60-minute pretreatment with CM572, followed by extensive washing to remove ligand, indicating an irreversible effect consistent with the irreversible binding data. Western blot analysis revealed that CM572 also induced cleavage activation of proapoptotic BH3-interacting domain death agonist. These data suggest irreversible agonist-like activity. Low concentrations of CM572 that were minimally effective were able to attenuate significantly the calcium signal and cell death induced by the sigma-2 agonist CB-64D [(+)-1R,5R-(E)-8-benzylidene-5-(3-hydroxyphenyl)-2-methylmorphan-7-one]. CM572 was also cytotoxic against PANC-1 pancreatic and MCF-7 breast cancer cell lines. The cytotoxic activity of CM572 was selective for cancer cells over normal cells, being much less potent against primary human melanocytes and human mammary epithelial cells. Taken together, these data show that CM572 is a selective, irreversible sigma-2 receptor partial agonist. This novel irreversible ligand may further our understanding of the endogenous role of this receptor, in addition to having potential use in targeted

  10. Aerodynamic Control using Distributed Active Bleed

    NASA Astrophysics Data System (ADS)

    Kearney, John; Glezer, Ari

    2015-11-01

    The global aerodynamic loads on a stationary and pitching airfoil at angles of attack beyond the static and dynamic stall margins, respectively are controlled in wind tunnel experiments using regulated distributed bleed driven by surface pressure differences. High-speed PIV and proper orthogonal decomposition of the vorticity flux on the static airfoil show that the bleed engenders trains of discrete vortices that advect along the surface and are associated with a local instability that is manifested by a time-averaged bifurcation of the vorticity layer near the bleed outlets and alters the vorticity flux over the airfoil and thereby the aerodynamic loads. Active bleed is used on a dynamically pitching airfoil (at reduced frequencies up to k = 0.42) to modulate the evolution of vorticity concentrations during dynamic stall. Time-periodic bleed improved the pitch stability by reducing adverse pitching moment (``negative damping'') that can precipitate structural instabilities. At the same time, the maintains the cycle-average loads to within 5% of the base flow levels by segmenting the vorticity layer during upstroke and promoting early flow attachment during downstroke segments of the pitch cycle. Supported by Georgia Tech VLRCOE.

  11. Blended Wing Body Systems Studies: Boundary Layer Ingestion Inlets With Active Flow Control

    NASA Technical Reports Server (NTRS)

    Geiselhart, Karl A. (Technical Monitor); Daggett, David L.; Kawai, Ron; Friedman, Doug

    2003-01-01

    A CFD analysis was performed on a Blended Wing Body (BWB) aircraft with advanced, turbofan engines analyzing various inlet configurations atop the aft end of the aircraft. The results are presented showing that the optimal design for best aircraft fuel efficiency would be a configuration with a partially buried engine, short offset diffuser using active flow control, and a D-shaped inlet duct that partially ingests the boundary layer air in flight. The CFD models showed that if active flow control technology can be satisfactorily developed, it might be able to control the inlet flow distortion to the engine fan face and reduce the powerplant performance losses to an acceptable level. The weight and surface area drag benefits of a partially submerged engine shows that it might offset the penalties of ingesting the low energy boundary layer air. The combined airplane performance of such a design might deliver approximately 5.5% better aircraft fuel efficiency over a conventionally designed, pod-mounted engine.

  12. THE INFLUENCE OF MONTELUKAST ON THE ACTIVITY OF THE AUTONOMIC NERVOUS SYSTEM ESTIMATED BY HEART RATE VARIABILITY IN EXPERIMENTAL PARTIAL BLADDER OUTLET OBSTRUCTION IN RATS.

    PubMed

    Dobrek, Łukasz; Skowron, Beata; Baranowska, Agnieszka; Zurowski, Daniel; Thor, Piotr Jan

    2016-01-01

    Due to their paracrine action, leukotrienes released from the urothelium are involved in control of the bladder function. Anti-leukotriene agents appear to exert an ameliorating effect in bladder overactivity. It is unknown, whether their possible, modulatory impact on the autonomic nervous system (ANS) activity may also contribute to the potentially beneficial effect of those compounds. Therefore, our aim was to indirectly estimate the ANS function using the heart rate variability (HRV) study in rats with experimental partial bladder outlet obstruction (PBOO), reflecting human benign prostatic hyperplasia (BPH), treated with leukotriene receptor antagonist - montelukast (MLKT). Twenty rats with surgically induced PBOO lasting for 14 days, divided into two groups: group 1 (10 control subjects) and group 2 (10 MLKT-treated rats; 2 mg/rat/day) were subjected to HRV recordings, preceded by daily urine collection and a subsequent cystectomy with histopathological evaluation of collected bladders. Standard HRV time and spectral parameters were calculated. MLKT-treated animals demonstrated an increase in power of non-normalized LF (low frequency) and HF (high frequency) components with no change of the total HRV power. Moreover, an increase and decrease in normalized nLF and nHF, respectively, were assessed in those animals compared to the control. Additionally, a decrease in daily diuresis measurement was demonstrated in MLKT-treated animals. Montelukast treatment resulted in the functional ANS status re-arrangement, with sympathetic overdrive and parasympathetic withdrawal. Those changes may contribute to alleviation of bladder overactivity symptoms, independently on leukotriene receptors blockade. PMID:27476297

  13. Aggregate Size and Architecture Determine Microbial Activity Balance for One-Stage Partial Nitritation and Anammox ▿

    PubMed Central

    Vlaeminck, Siegfried E.; Terada, Akihiko; Smets, Barth F.; De Clippeleir, Haydée; Schaubroeck, Thomas; Bolca, Selin; Demeestere, Lien; Mast, Jan; Boon, Nico; Carballa, Marta; Verstraete, Willy

    2010-01-01

    Aerobic ammonium-oxidizing bacteria (AerAOB) and anoxic ammonium-oxidizing bacteria (AnAOB) cooperate in partial nitritation/anammox systems to remove ammonium from wastewater. In this process, large granular microbial aggregates enhance the performance, but little is known about granulation so far. In this study, three suspended-growth oxygen-limited autotrophic nitrification-denitrification (OLAND) reactors with different inoculation and operation (mixing and aeration) conditions, designated reactors A, B, and C, were used. The test objectives were (i) to quantify the AerAOB and AnAOB abundance and the activity balance for the different aggregate sizes and (ii) to relate aggregate morphology, size distribution, and architecture putatively to the inoculation and operation of the three reactors. A nitrite accumulation rate ratio (NARR) was defined as the net aerobic nitrite production rate divided by the anoxic nitrite consumption rate. The smallest reactor A, B, and C aggregates were nitrite sources (NARR, >1.7). Large reactor A and C aggregates were granules capable of autonomous nitrogen removal (NARR, 0.6 to 1.1) with internal AnAOB zones surrounded by an AerAOB rim. Around 50% of the autotrophic space in these granules consisted of AerAOB- and AnAOB-specific extracellular polymeric substances. Large reactor B aggregates were thin film-like nitrite sinks (NARR, <0.5) in which AnAOB were not shielded by an AerAOB layer. Voids and channels occupied 13 to 17% of the anoxic zone of AnAOB-rich aggregates (reactors B and C). The hypothesized granulation pathways include granule replication by division and budding and are driven by growth and/or decay based on species-specific physiology and by hydrodynamic shear and mixing. PMID:19948857

  14. Indium-111-labeled platelets: effect of heparin on uptake by venous thrombi and relationship to the activated partial thromboplastin time

    SciTech Connect

    Fedullo, P.F.; Moser, K.M.; Moser, K.S.; Konopka, R.; Hartman, M.T.

    1982-09-01

    The goal of heparin thepapy in deep vein thrombosis is to prevent thrombus extension. The relationship between thrombus extension and the results of coagulation tests used to monitor heparin thepapy is unclear. To expose this relationship, we studied the effect of several heparin regimens on the accretion of indium-111-labeled platelets on fresh venous thrombi, as detected by gamma imaging, and monitored the activated partial thromboplastin time (APTT). Six dogs were treated with a 300-U/kg bolus of heparin followed by a 90-U/kg/hour heparin infusion, a dose of heparin sufficient to increase the APTT to levels greater than eight times baseline (APTT ratio); platelet accretion (thrombus imaging) occurred only after the heparin effect was reversed with protamine sulfate. Nineteen dogs were treated with a 150-U/kg bolus of heparin followed by a 4-hour, 45-U/kg/hour heparin infusion; a thrombus was demonstrated only after protamine injection in 12 (mean APTT ratio 1.3 +/- 0.19) and before protamine injection in seven. In thirteen of these 19 dogs, 30 minutes separated the platelet injection from heparin therapy, while in six this duration was less than 30 minutes. In four of these six dogs, thrombi were demonstrated before protamine therapy and at APTT ratios greater than 3.0. Finally, 10 dogs were treated with a 100-U/kg bolus followed by a 3-hour, 50-U/kg/hour heparin infusion, after which the APTT was allowed to return to baseline values spontaneously. In all 10 dogs, a thrombus was demonstrated only after cessation of the heparin infusion, and at a mean APTT ratio of 1.4 +/- 0.15 times baseline. These results suggest that, except with very early platelet injection, platelet accretion by thrombi is consistently inhibited by heparin at APTT ratios greater than 2.5.

  15. Active control of buckling of flexible beams

    NASA Technical Reports Server (NTRS)

    Baz, A.; Tampe, L.

    1989-01-01

    Mathematical models are presented that simulate the dynamic characteristics of shape memory alloy actuators made of nickel-titanium alloy (Nitinol) controlling the buckling of compressive structural members. A closed-loop computer-controlled system has been designed, based on the proposed mathematical models, and has been implemented to control the buckling of simple beams. The performance of the computer-controlled system is evaluated experimentally and compared with the theoretical predictions to validate the developed models. The results emphasized the importance of buckling control and suggest the potential of shape memory alloy actuators as attractive means for controlling structural deformation in a simple and reliable way.

  16. Comparison of three different dressings for partial thickness burns in children: study protocol for a randomised controlled trial

    PubMed Central

    2013-01-01

    Background In the paediatric population, pain and distress associated with burn injuries during wound care procedures remain a constant challenge. Although silver dressings are the gold standard for burn care in Australasia, very few high-level trials have been conducted that compare silver dressings to determine which will provide the best level of care clinically. Therefore, for paediatric patients in particular, identifying silver dressings that are associated with lower levels of pain and rapid wound re-epithelialisation is imperative. This study will determine whether there is a difference in time to re-epithelialisation and pain and distress experienced during wound care procedures among Acticoat™, Acticoat™ combined with Mepitel™ and Mepilex Ag™ dressings for acute, paediatric partial thickness burns. Methods/Design Children aged 0 to 15 years with an acute partial thickness (superficial partial to deep partial thickness inclusive) burn injury and a burn total body surface area of ≤10% will be eligible for the trial. Patients will be randomised to one of the three dressing groups: (1) Acticoat™ or (2) Acticoat™ combined with Mepitel™ or (3) Mepilex Ag™. A minimum of 28 participants will be recruited for each treatment group. Primary measures of pain, distress and healing will be repeated at each dressing change until complete wound re-epithelialisation occurs or skin grafting is required. Additional data collected will include infection status at each dressing change, physical function, scar outcome and scar management requirements, cost effectiveness of each dressing and staff perspectives of the dressings. Discussion The results of this study will determine the effects of three commonly used silver and silicone burn dressing combinations on the rate of wound re-epithelialisation and pain experienced during dressing procedures in acute, paediatric partial thickness burn injuries. Trial registration Australian New Zealand Clinical Trials

  17. Extending the structure-activity relationship of anthranilic acid derivatives as farnesoid X receptor modulators: development of a highly potent partial farnesoid X receptor agonist.

    PubMed

    Merk, Daniel; Lamers, Christina; Ahmad, Khalil; Carrasco Gomez, Roberto; Schneider, Gisbert; Steinhilber, Dieter; Schubert-Zsilavecz, Manfred

    2014-10-01

    The ligand activated transcription factor nuclear farnesoid X receptor (FXR) is involved as a regulator in many metabolic pathways including bile acid and glucose homeostasis. Therefore, pharmacological activation of FXR seems a valuable therapeutic approach for several conditions including metabolic diseases linked to insulin resistance, liver disorders such as primary biliary cirrhosis or nonalcoholic steatohepatitis, and certain forms of cancer. The available FXR agonists, however, activate the receptor to the full extent which might be disadvantageous over a longer time period. Hence, partial FXR activators are required for long-term treatment of metabolic disorders. We here report the SAR of anthranilic acid derivatives as FXR modulators and development, synthesis, and characterization of compound 51, which is a highly potent partial FXR agonist in a reporter gene assay with an EC50 value of 8 ± 3 nM and on mRNA level in liver cells. PMID:25255039

  18. Active controllers and the time duration to learn a task

    NASA Technical Reports Server (NTRS)

    Repperger, D. W.; Goodyear, C.

    1986-01-01

    An active controller was used to help train naive subjects involved in a compensatory tracking task. The controller is called active in this context because it moves the subject's hand in a direction to improve tracking. It is of interest here to question whether the active controller helps the subject to learn a task more rapidly than the passive controller. Six subjects, inexperienced to compensatory tracking, were run to asymptote root mean square error tracking levels with an active controller or a passive controller. The time required to learn the task was defined several different ways. The results of the different measures of learning were examined across pools of subjects and across controllers using statistical tests. The comparison between the active controller and the passive controller as to their ability to accelerate the learning process as well as reduce levels of asymptotic tracking error is reported here.

  19. Mainstream partial nitritation and anammox in a 200,000 m3/day activated sludge process in Singapore: scale-down by using laboratory fed-batch reactor.

    PubMed

    Yeshi, Cao; Hong, Kwok Bee; van Loosdrecht, Mark C M; Daigger, Glen T; Yi, Png Hui; Wah, Yuen Long; Chye, Chua Seng; Ghani, Yahya Abd

    2016-01-01

    A laboratory fed-batch reactor has been used to study under controlled conditions the performance of partial nitritation/anammox for the 200,000 m(3)/day step-feed activated sludge process at the Changi Water Reclamation Plant, Singapore. The similarity of the concentrations of NH(4), NO(2), NO(3), PO(4), suspended chemical oxygen demand (sCOD), pH, and alkalinity (ALK) between the on-site process and laboratory reactor illustrates that the laboratory fed-batch reactor can be used to simulate the site performance. The performance of the reactor fed by primary effluent illustrated the existence of anammox and heterotrophic denitrification and apparent excessive biological phosphorus removal as observed from the site. The performance of the reactor fed by final effluent proved the presence of anammox process on site. Both the laboratory reactor and on-site process showed that higher influent 5-day biochemical oxygen demand/total nitrogen (BOD(5)/TN) (COD/TN) ratio increases the nitrogen removal efficiency of the process. PMID:27386982

  20. Quasi-modal vibration control by means of active control bearings

    NASA Technical Reports Server (NTRS)

    Nonami, K.; Fleming, D. P.

    1986-01-01

    This paper investigates a design method of an active control bearing system with only velocity feedback. The study provides a new quasi-modal control method for a control system design of an active control bearing system in which feedback coefficients are determined on the basis of a modal analysis. Although the number of sensors and actuators is small, this quasi-modal control method produces a control effect close to an ideal modal control.

  1. Low Activity Waste Feed Process Control Strategy

    SciTech Connect

    STAEHR, T.W.

    2000-06-14

    The primary purpose of this document is to describe the overall process control strategy for monitoring and controlling the functions associated with the Phase 1B high-level waste feed delivery. This document provides the basis for process monitoring and control functions and requirements needed throughput the double-shell tank system during Phase 1 high-level waste feed delivery. This document is intended to be used by (1) the developers of the future Process Control Plan and (2) the developers of the monitoring and control system.

  2. Active flutter control for flexible vehicles, volume 1

    NASA Technical Reports Server (NTRS)

    Mahesh, J. K.; Garrard, W. L.; Stones, C. R.; Hausman, P. D.

    1979-01-01

    An active flutter control methodology based on linear quadratic gaussian theory and its application to the control of a super critical wing is presented. Results of control surface and sensor position optimization are discussed. Both frequency response matching and residualization used to obtain practical flutter controllers are examined. The development of algorithms and computer programs for flutter modeling and active control design procedures is reported.

  3. A gene-centric analysis of activated partial thromboplastin time and activated protein C resistance using the HumanCVD focused genotyping array

    PubMed Central

    Gaunt, Tom R; Lowe, Gordon DO; Lawlor, Debbie A; Casas, Juan-Pablo; Day, Ian NM

    2013-01-01

    Activated partial thromboplastin time (aPTT) is an important routine measure of intrinsic blood coagulation. Addition of activated protein C (APC) to the aPTT test to produce a ratio, provides one measure of APC resistance. The associations of some genetic mutations (eg, factor V Leiden) with these measures are established, but associations of other genetic variations remain to be established. The objective of this work was to test for association between genetic variants and blood coagulation using a high-density genotyping array. Genetic association with aPTT and APC resistance was analysed using a focused genotyping array that tests approximately 50 000 single-nucleotide polymorphisms (SNPs) in nearly 2000 cardiovascular candidate genes, including coagulation pathway genes. Analyses were conducted on 2544 European origin women from the British Women's Heart and Health Study. We confirm associations with aPTT at the coagulation factor XII (F12)/G protein-coupled receptor kinase 6 (GRK6) and kininogen 1 (KNG1)/histidine-rich glycoprotein (HRG) loci, and identify novel SNPs at the ABO locus and novel locus kallikrein B (KLKB1)/F11. In addition, we confirm association between APC resistance and factor V Leiden mutation, and identify novel SNP associations with APC resistance in the HRG and F5/solute carrier family 19 member 2 (SLC19A2) regions. In conclusion, variation at several genetic loci influences intrinsic blood coagulation as measured by both aPTT and APC resistance. PMID:23188048

  4. Level of asthma control and its impact on activities of daily living in asthma patients in Brazil*

    PubMed Central

    Gazzotti, Mariana Rodrigues; Nascimento, Oliver Augusto; Montealegre, Federico; Fish, James; Jardim, José Roberto

    2013-01-01

    OBJECTIVE: To evaluate the impact of asthma on activities of daily living and on health status in patients with controlled, partially controlled, or uncontrolled asthma in Brazil. METHODS: We used data related to 400 patients in four Brazilian cities (São Paulo, Rio de Janeiro, Salvador, and Curitiba), obtained in a survey conducted throughout Latin America in 2011. All study subjects were > 12 years of age and completed a standardized questionnaire in face-to-face interviews. The questions addressed asthma control, hospitalizations, emergency room visits, and school/work absenteeism, as well as the impact of asthma on the quality of life, sleep, and leisure. The level of asthma control was determined in accordance with the Global Initiative for Asthma criteria. RESULTS: Among the 400 respondents, asthma was controlled in 37 (9.3%), partially controlled in 226 (56.5%), and uncontrolled in 137 (34.2%). The numbers of patients with uncontrolled or partially controlled asthma who visited the emergency room, who were hospitalized, and who missed school/work were higher than were those of patients with controlled asthma (p = 0.001, p = 0.05, and p = 0.01, respectively). Among those with uncontrolled asthma, the impact of the disease on activities of daily living, sleep, social activities, and normal physical exertion was greater than it was among those with controlled or partially controlled asthma (p < 0.001). CONCLUSIONS: In Brazil, asthma treatment should be monitored more closely in order to increase treatment adherence and, consequently, the level of asthma control, which can improve patient quality of life and minimize the negative impact of the disease. PMID:24310625

  5. Active parallel redundancy for electronic integrator-type control circuits

    NASA Technical Reports Server (NTRS)

    Peterson, R. A.

    1971-01-01

    Circuit extends concept of redundant feedback control from type-0 to type-1 control systems. Inactive channels are slaves to the active channel, if latter fails, it is rejected and slave channel is activated. High reliability and elimination of single-component catastrophic failure are important in closed-loop control systems.

  6. Student Activity Funds: Creating a System of Controls That Work.

    ERIC Educational Resources Information Center

    Cuzzetto, Charles

    1995-01-01

    Although student-activity funds usually represent a small portion of school-system monies, their very nature makes them a high risk. Outlines three steps for maintaining an efficient and effective system of controls over student-activity funds: (1) identifying control issues; (2) designing a control system; and (3) using checks and balances.…

  7. Attitude control with active actuator saturation prevention

    NASA Astrophysics Data System (ADS)

    Forbes, James Richard

    2015-02-01

    Spacecraft attitude control in the presence of actuator saturation is considered. The attitude controller developed has two components: a proportional component and an angular velocity component. The proportional control has a special form that depends on the attitude parameterization. The angular velocity control is realized by a strictly positive real system with its own input nonlinearity. The strictly positive real system can filter noise in the angular velocity measurement. With this control architecture the torques applied to the body are guaranteed to be below a predetermined value, thus preventing saturation of the actuators. The closed-loop equilibrium point corresponding to the desired attitude is shown to be asymptotically stable. Additionally, the control law does not require specific knowledge of the body's inertia properties, and is therefore robust to such modelling errors.

  8. Validation of model based active control of combustion instability

    SciTech Connect

    Fleifil, M.; Ghoneim, Z.; Ghoniem, A.F.

    1998-07-01

    The demand for efficient, company and clean combustion systems have spurred research into the fundamental mechanisms governing their performance and means of interactively changing their performance characteristics. Thermoacoustic instability which is frequently observed in combustion systems with high power density, when burning close to the lean flammability limit, or using exhaust gas recirculation to meet more stringent emissions regulations, etc. Its occurrence and/or means to mitigate them passively lead to performance degradation such as reduced combustion efficiency, high local heat transfer rates, increase in the mixture equivalence ratio or system failure due to structural damage. This paper reports on their study of the origin of thermoacoustic instability, its dependence on system parameters and the means of actively controlling it. The authors have developed an analytical model of thermoacoustic instability in premixed combustors. The model combines a heat release dynamics model constructed using the kinematics of a premixed flame stabilized behind a perforated plate with the linearized conservation equations governing the system acoustics. This formulation allows model based controller design. In order to test the performance of the analytical model, a numerical solution of the partial differential equations governing the system has been carried out using the principle of harmonic separation and focusing on the dominant unstable mode. This leads to a system of ODEs governing the thermofluid variables. Analytical predictions of the frequency and growth ate of the unstable mode are shown to be in good agreement with the numerical simulations as well s with those obtained using experimental identification techniques when applied to a laboratory combustor. The authors use these results to confirm the validity of the assumptions used in formulating the analytical model. A controller based on the minimization of a cost function using the LQR technique has

  9. Coherent control of birefringence and optical activity

    NASA Astrophysics Data System (ADS)

    Mousavi, Seyedmohammad A.; Plum, Eric; Shi, Jinhui; Zheludev, Nikolay I.

    2014-07-01

    We show that polarization effects due to anisotropy and chirality affecting a wave propagating through a thin slab of material can be controlled by another electromagnetic wave. No nonlinearity of the metamaterial slab is required and the control can be exercised at arbitrarily low intensities. In proof-of-principle experiments with anisotropic and chiral microwave metamaterials, we show that manifestations of linear and circular birefringence and dichroism can be modulated by the control wave from their maximum value to zero.

  10. Modeling the Benchmark Active Control Technology Wind-Tunnel Model for Active Control Design Applications

    NASA Technical Reports Server (NTRS)

    Waszak, Martin R.

    1998-01-01

    This report describes the formulation of a model of the dynamic behavior of the Benchmark Active Controls Technology (BACT) wind tunnel model for active control design and analysis applications. The model is formed by combining the equations of motion for the BACT wind tunnel model with actuator models and a model of wind tunnel turbulence. The primary focus of this report is the development of the equations of motion from first principles by using Lagrange's equations and the principle of virtual work. A numerical form of the model is generated by making use of parameters obtained from both experiment and analysis. Comparisons between experimental and analytical data obtained from the numerical model show excellent agreement and suggest that simple coefficient-based aerodynamics are sufficient to accurately characterize the aeroelastic response of the BACT wind tunnel model. The equations of motion developed herein have been used to aid in the design and analysis of a number of flutter suppression controllers that have been successfully implemented.

  11. Tuning of active vibration controllers for ACTEX by genetic algorithm

    NASA Astrophysics Data System (ADS)

    Kwak, Moon K.; Denoyer, Keith K.

    1999-06-01

    This paper is concerned with the optimal tuning of digitally programmable analog controllers on the ACTEX-1 smart structures flight experiment. The programmable controllers for each channel include a third order Strain Rate Feedback (SRF) controller, a fifth order SRF controller, a second order Positive Position Feedback (PPF) controller, and a fourth order PPF controller. Optimal manual tuning of several control parameters can be a difficult task even though the closed-loop control characteristics of each controller are well known. Hence, the automatic tuning of individual control parameters using Genetic Algorithms is proposed in this paper. The optimal control parameters of each control law are obtained by imposing a constraint on the closed-loop frequency response functions using the ACTEX mathematical model. The tuned control parameters are then uploaded to the ACTEX electronic control electronics and experiments on the active vibration control are carried out in space. The experimental results on ACTEX will be presented.

  12. Lipid transfer protein I facilitated transfer of cyclosporine from low- to high-density lipoproteins is only partially dependent on its cholesteryl ester transfer activity.

    PubMed

    Wasan, K M; Ramaswamy, M; Wong, W; Pritchard, P H

    1998-02-01

    The purpose of this study was to determine if lipid transfer protein (LTP I) regulates the plasma lipoprotein distribution of cyclosporine (CSA). Experimental strategies that involved the supplementation and inhibition of LTP I were used to test these hypotheses. Incubation of CSA with human plasma supplemented with exogenous LTP I resulted in a significantly greater percentage of CSA recovered in the high-density lipoprotein (HDL)/lipoprotein deficient plasma (LPDP) fraction than in the low-density lipoprotein (LDL)/very low-density lipoprotein (VLDL) fraction compared to plasma which had no exogenous LTP I added. Incubation of radiolabeled cholesteryl ester (CE) or CSA-enriched HDL or LDL in T150 buffer supplemented with LTP I resulted in a significantly greater percentage of CE than CSA being transferred from HDL to LDL and LDL to HDL. However, the percent transfer from LDL to HDL was significantly lower for CE than CSA when these particles were incubated in LPDP that contained endogenous LTP I. The percent transfer of CE from HDL to LDL and LDL to HDL was significantly decreased in the presence of TP2, a monoclonal antibody directed against LTP I, compared to controls. The percent transfer of CSA from LDL to HDL was significantly decreased in the presence of TP2. However, the percent transfer of CSA from HDL to LDL in the presence of TP2 was not significantly different compared to controls. These findings suggest that the transfer of CSA between HDL and LDL is only partially facilitated through LTP I CE transfer activity. PMID:9454803

  13. Position dependent rate dampening in any active hand controller

    NASA Technical Reports Server (NTRS)

    Gregory, William W. (Inventor); Kauffman, James W. (Inventor)

    1994-01-01

    A control system for an active hand controller, for example, uses a control stick connected to and controlled by a motor. Electronics are provided to control the motor to eliminate oscillations due to motor torque and high gain due to breakout at the control stick when the control stick is at about its null position. Both hardware as well as software implementations can provide position dependent dampening to the control sticks such that when the control stick is located about a null position, a higher rate of dampening is provided than when the control stick is located outside the null position, when a lower rate of dampening is provided. The system provides a stable active hand controller control stick without degraded force and feel characteristics of the system.

  14. Prothrombin Time and Activated Partial Thromboplastin Time Testing: A Comparative Effectiveness Study in a Million-Patient Sample

    PubMed Central

    Capoor, Manu N.; Stonemetz, Jerry L.; Baird, John C.; Ahmed, Fahad S.; Awan, Ahsan; Birkenmaier, Christof; Inchiosa, Mario A.; Magid, Steven K.; McGoldrick, Kathryn; Molmenti, Ernesto; Naqvi, Sajjad; Parker, Stephen D.; Pothula, S. M.; Shander, Aryeh; Steen, R. Grant; Urban, Michael K.; Wall, Judith; Fischetti, Vincent A.

    2015-01-01

    Background A substantial fraction of all American healthcare expenditures are potentially wasted, and practices that are not evidence-based could contribute to such waste. We sought to characterize whether Prothrombin Time (PT) and activated Partial Thromboplastin Time (aPTT) tests of preoperative patients are used in a way unsupported by evidence and potentially wasteful. Methods and Findings We evaluated prospectively-collected patient data from 19 major teaching hospitals and 8 hospital-affiliated surgical centers in 7 states (Delaware, Florida, Maryland, Massachusetts, New Jersey, New York, Pennsylvania) and the District of Columbia. A total of 1,053,472 consecutive patients represented every patient admitted for elective surgery from 2009 to 2012 at all 27 settings. A subset of 682,049 patients (64.7%) had one or both tests done and history and physical (H&P) records available for analysis. Unnecessary tests for bleeding risk were defined as: PT tests done on patients with no history of abnormal bleeding, warfarin therapy, vitamin K-dependent clotting factor deficiency, or liver disease; or aPTT tests done on patients with no history of heparin treatment, hemophilia, lupus anticoagulant antibodies, or von Willebrand disease. We assessed the proportion of patients who received PT or aPTT tests who lacked evidence-based reasons for testing. Conclusions This study sought to bring the availability of big data together with applied comparative effectiveness research. Among preoperative patients, 26.2% received PT tests, and 94.3% of tests were unnecessary, given the absence of findings on H&P. Similarly, 23.3% of preoperative patients received aPTT tests, of which 99.9% were unnecessary. Among patients with no H&P findings suggestive of bleeding risk, 6.6% of PT tests and 7.1% of aPTT tests were either a false positive or a true positive (i.e. indicative of a previously-undiagnosed potential bleeding risk). Both PT and aPTT, designed as diagnostic tests, are

  15. Optimal cooperative control synthesis of active displays

    NASA Technical Reports Server (NTRS)

    Garg, S.; Schmidt, D. K.

    1986-01-01

    The utility of augmenting displays to aid the human operator in controlling high order complex systems is well known. Analytical evaluation of various display designs for a simple k/s sup 2 plant in a compensatory tracking task using an optimal Control Model (OCM) of human behavior is carried out. This analysis reveals that significant improvement in performance should be obtained by skillful integration of key information into the display dynamics. The cooperative control synthesis technique previously developed to design pilot-optimal control augmentation is extended to incorporate the simultaneous design of performance enhancing augmented displays. The application of the cooperative control synthesis technique to the design of augmented displays is discussed for the simple k/s sup 2 plant. This technique is intended to provide a systematic approach to design optimally augmented displays tailored for specific tasks.

  16. Optimal cooperative control synthesis of active displays

    NASA Technical Reports Server (NTRS)

    Garg, S.; Schmidt, D. K.

    1985-01-01

    A technique is developed that is intended to provide a systematic approach to synthesizing display augmentation for optimal manual control in complex, closed-loop tasks. A cooperative control synthesis technique, previously developed to design pilot-optimal control augmentation for the plant, is extended to incorporate the simultaneous design of performance enhancing displays. The technique utilizes an optimal control model of the man in the loop. It is applied to the design of a quickening control law for a display and a simple K/s(2) plant, and then to an F-15 type aircraft in a multi-channel task. Utilizing the closed loop modeling and analysis procedures, the results from the display design algorithm are evaluated and an analytical validation is performed. Experimental validation is recommended for future efforts.

  17. Optimal cooperative control synthesis of active displays

    NASA Technical Reports Server (NTRS)

    Gary, Sanjay; Schmidt, David K.

    1987-01-01

    A technique is developed that is intended to provide a systematic approach to synthesizing display augmentation for optimal manual control in complex, closed-loop tasks. A cooperative control synthesis technique, previously developed to design pilot-optimal control augmentation for the plant, is extended to incorporate the simultaneous design of performance enhancing displays. The technique utilizes an optimal control model of the man in the loop. It is applied to the design of a quickening control law for a display and a simple K/(s squared) plant, and then to an F-15 type aircraft in a multichannel task. Utilizing the closed-loop modeling and analysis procedures, the results from the display design algorithm are evaluated and an analytical validation is performed. Experimental validation is recommended for future efforts.

  18. Optimal cooperative control synthesis of active displays

    NASA Technical Reports Server (NTRS)

    Garg, S.; Schmidt, D. K.

    1985-01-01

    The utility of augmenting displays to aid the human operator in controlling high order complex systems is well known. Analytical evaluations of various display designs for a simple k/s-squared plant in a compensatory tracking task using an Optimal Control Model (OCM) of human behavior is carried out. This analysis reveals that significant improvement in performance should be obtained by skillful integration of key information into the display dynamics. The cooperative control synthesis technique previously developed to design pilot-optimal control augmentation is extended to incorporate the simultaneous design of performance enhancing augmented displays. The application of the cooperative control synthesis technique to the design of augmented displays is discussed for the simple k/s-squared plant. This technique is intended to provide a systematic approach to design optimally augmented displays tailored for specific tasks.

  19. Epilepsy (partial)

    PubMed Central

    2011-01-01

    Introduction About 3% of people will be diagnosed with epilepsy during their lifetime, but about 70% of people with epilepsy eventually go into remission. Methods and outcomes We conducted a systematic review and aimed to answer the following clinical questions: What are the effects of starting antiepileptic drug treatment following a single seizure? What are the effects of drug monotherapy in people with partial epilepsy? What are the effects of additional drug treatments in people with drug-resistant partial epilepsy? What is the risk of relapse in people in remission when withdrawing antiepileptic drugs? What are the effects of behavioural and psychological treatments for people with epilepsy? What are the effects of surgery in people with drug-resistant temporal lobe epilepsy? We searched: Medline, Embase, The Cochrane Library, and other important databases up to July 2009 (Clinical Evidence reviews are updated periodically; please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA). Results We found 83 systematic reviews, RCTs, or observational studies that met our inclusion criteria. We performed a GRADE evaluation of the quality of evidence for interventions. Conclusions In this systematic review we present information relating to the effectiveness and safety of the following interventions: antiepileptic drugs after a single seizure; monotherapy for partial epilepsy using carbamazepine, gabapentin, lamotrigine, levetiracetam, phenobarbital, phenytoin, sodium valproate, or topiramate; addition of second-line drugs for drug-resistant partial epilepsy (allopurinol, eslicarbazepine, gabapentin, lacosamide, lamotrigine, levetiracetam, losigamone, oxcarbazepine, retigabine, tiagabine, topiramate, vigabatrin, or zonisamide); antiepileptic drug withdrawal for people with partial or

  20. Active Combustion Control for Aircraft Gas Turbine Engines

    NASA Technical Reports Server (NTRS)

    DeLaat, John C.; Breisacher, Kevin J.; Saus, Joseph R.; Paxson, Daniel E.

    2000-01-01

    Lean-burning combustors are susceptible to combustion instabilities. Additionally, due to non-uniformities in the fuel-air mixing and in the combustion process, there typically exist hot areas in the combustor exit plane. These hot areas limit the operating temperature at the turbine inlet and thus constrain performance and efficiency. Finally, it is necessary to optimize the fuel-air ratio and flame temperature throughout the combustor to minimize the production of pollutants. In recent years, there has been considerable activity addressing Active Combustion Control. NASA Glenn Research Center's Active Combustion Control Technology effort aims to demonstrate active control in a realistic environment relevant to aircraft engines. Analysis and experiments are tied to aircraft gas turbine combustors. Considerable progress has been shown in demonstrating technologies for Combustion Instability Control, Pattern Factor Control, and Emissions Minimizing Control. Future plans are to advance the maturity of active combustion control technology to eventual demonstration in an engine environment.

  1. Acceleration-Augmented LQG Control of an Active Magnetic Bearing

    NASA Technical Reports Server (NTRS)

    Feeley, Joseph J.

    1993-01-01

    A linear-quadratic-gaussian (LQG) regulator controller design for an acceleration-augmented active magnetic bearing (AMB) is outlined. Acceleration augmentation is a key feature in providing improved dynamic performance of the controller. The optimal control formulation provides a convenient method of trading-off fast transient response and force attenuation as control objectives.

  2. Actively controlled shaft seals for aerospace applications

    NASA Technical Reports Server (NTRS)

    Salant, Richard F.

    1991-01-01

    The main objective is to determine the feasibility of utilizing controllable mechanical seals for aerospace applications. A potential application was selected as a demonstration case: the buffer gas seal in a LOX (liquid oxygen) turbopump. Currently, floating ring seals are used in this application. Their replacement with controllable mechanical seals would result in substantially reduced leakage rates. This would reduce the required amount of stored buffer gas, and therefore increase the vehicle payload. For such an application, a suitable controllable mechanical seal was designed and analyzed.

  3. Developmental change in EEG theta activity in the medial prefrontal cortex during response control.

    PubMed

    Liu, Zhong-Xu; Woltering, Steven; Lewis, Marc D

    2014-01-15

    Cognitive control functions continue to improve from infancy until early adulthood, allowing flexible adaptation to a complex environment. However, it remains controversial how this development in cognitive capabilities is mediated by changes in cortical activity: both age-related increases and decreases of mediofrontal neural activity have been observed and interpreted as neural underpinnings of this functional development. To better understand this developmental process, we examined EEG theta activity in the mediofrontal region using a Go/No-go response control task. We found that both pre-stimulus baseline theta-power and theta-power during the response control task, without baseline-correction, decreased with age. Conversely, when task-related theta-power was baseline corrected (using a ratio method), it exhibited a positive developmental trajectory. The age-related theta-power increase was source-localized to the anterior cingulate cortex. This increase in theta activity also partially mediated age-related improvements in response control and was greatest in a condition that demanded greater effort. Theta activity in older children also showed greater temporal reliability across trials as measured by inter-trial phase-coherence. Interestingly, directly subtracting baseline activity from task-related activity did not yield significant developmental effects, which highlights the necessity of separating and contrasting the pre-stimulus baseline with task-related processing in the understanding of neurodevelopmental changes. PMID:24007804

  4. Identification of the affected lower limb and unaffected side motor functions as determinants of activities of daily living performance in stroke patients using partial correlation analysis

    PubMed Central

    Fujita, Takaaki; Sato, Atsushi; Togashi, Yui; Kasahara, Ryuichi; Ohashi, Takuro; Tsuchiya, Kenji; Yamamoto, Yuichi; Otsuki, Koji

    2015-01-01

    [Purpose] This study aimed to clarify the independent impact of the affected upper and lower limb, trunk, and unaffected side motor functions on activities of daily living in stroke patients using partial correlation analysis. [Subjects and Methods] This retrospective study included 77 stroke patients. Motor functions were assessed using the Stroke Impairment Assessment Set, and the activities of daily living performance was assessed using the Barthel index or Functional Independence Measure. Further, simple and partial correlation analyses were conducted between each motor function and activities of daily living parameter. [Results] Simple correlation analysis identified significant positive correlations for each pair. In contrast, partial correlation analysis only identified significant positive correlations between the affected lower limb or unaffected side functions and the Barthel index or Functional Independence Measure. This discrepancy between the two tests was explained by the significant interaction between the affected upper and lower limb functions and between the trunk and unaffected side functions. [Conclusion] The present study identified the affected lower limb and unaffected side motor functions as the major determinants of activities of daily living performance in stroke patients. These findings suggest that rehabilitation programs can be improved by targeting these areas. PMID:26311957

  5. PARTICULATE EMISSION MEASUREMENTS FROM CONTROLLED CONSTRUCTION ACTIVITIES

    EPA Science Inventory

    The report summarized the results of field testing of the effectiveness of control measures for sources of fugitive particulate emissions found at construction sites. The effectiveness of watering temporary, unpaved travel surfaces on emissions of particulate matter with aerodyna...

  6. Adaptive control of a packedbed reactor for the partial oxidation of n-butane to maleic anhydride; I. unsteady-state model and dynamics of the reactor

    SciTech Connect

    Not Available

    1984-01-01

    A nonadiabatic, fixed-bed catalytic reactor is analyzed on the basis of data for the highly exothermic partial oxidation of n-butane to maleic anhydride, in order to study multivariable adaptive control. The nonlinear partial differential equations describing the axial and radial gradients of concentration and temperature are converted into a set of nonlinear, ordinary differential and algebraic equations using orthogonal collocation, preserving the nonlinearity of the reaction term. These equations describe satisfactorily the steady state and dynamic behavior. This two-dimensional model enables the relationship between the time and temperature of reaction, and between the concentration of maleic anhydride and the hot-spot temperature to be expressed adequately by seconddegree, low-order transfer functions. This technique is applicable for any process of reaction in a packed bed.

  7. Active control of flexural vibrations in beams

    NASA Technical Reports Server (NTRS)

    Gerhold, Carl H.

    1987-01-01

    The feasibility of using piezoelectric actuators to control the flexural oscillations of large structures in space is investigated. Flexural oscillations are excited by impulsive loads. The vibratory response can degrade the pointing accuracy of cameras and antennae, and can cause high stresses at structural node points. Piezoelectric actuators have the advantage of exerting localized bending moments. In this way, vibration is controlled without exciting rigid body modes. The actuators are used in collocated sensor/driver pairs to form a feedback control system. The sensor produces a voltage that is proportional to the dynamic stress at the sensor location, and the driver produces a force that is proportional to the voltage applied to it. The analog control system amplifies and phase shifts the sensor signal to produce the voltage signal that is applied to the driver. The feedback control is demonstrated to increase the first mode damping in a cantilever beam by up to 100 percent, depending on the amplifier gain. The damping efficiency of the control system when the piezoelectrics are not optimally positioned at points of high stress in the beam is evaluated.

  8. Active chatter control in a milling machine

    SciTech Connect

    Dohner, J.L.; Hinnerichs, T.D.; Lauffer, J.P.

    1997-08-01

    The use of active feedback compensation to mitigate cutting instabilities in an advanced milling machine is discussed in this paper. A linear structural model delineating dynamics significant to the onset of cutting instabilities was combined with a nonlinear cutting model to form a dynamic depiction of an existing milling machine. The model was validated with experimental data. Modifications made to an existing machine model were used to predict alterations in dynamics due to the integration of active feedback compensation. From simulations, subcomponent requirements were evaluated and cutting enhancements were predicted. Active compensation was shown to enable more than double the metal removal rate over conventional milling machines. 25 refs., 10 figs., 1 tab.

  9. Isolation, Identification and Partial Characterization of a Lactobacillus casei Strain with Bile Salt Hydrolase Activity from Pulque.

    PubMed

    González-Vázquez, R; Azaola-Espinosa, A; Mayorga-Reyes, L; Reyes-Nava, L A; Shah, N P; Rivera-Espinoza, Y

    2015-12-01

    The aim of this study was to isolate, from pulque, Lactobacillus spp. capable of survival in simulated gastrointestinal stress conditions. Nine Gram-positive rods were isolated; however, only one strain (J57) shared identity with Lactobacillus and was registered as Lactobacillus casei J57 (GenBank accession: JN182264). The other strains were identified as Bacillus spp. The most significant observation during the test of tolerance to simulated gastrointestinal conditions (acidity, gastric juice and bile salts) was that L. casei J57 showed a rapid decrease (p ≤ 0.05) in the viable population at 0 h. Bile salts were the stress condition that most affected its survival, from which deoxycholic acid and the mix of bile salts (oxgall) were the most toxic. L. casei J57 showed bile salt hydrolase activity over primary and secondary bile salts as follows: 44.91, 671.72, 45.27 and 61.57 U/mg to glycocholate, taurocholate, glycodeoxycholate and taurodeoxycholate. In contrast, the control strain (L. casei Shirota) only showed activity over tauroconjugates. These results suggest that L. casei J57 shows potential for probiotic applications. PMID:26566892

  10. Experimental investigation of active machine tool vibration control

    NASA Astrophysics Data System (ADS)

    Rojas, J.; Liang, Chen; Geng, Zheng J.

    1996-05-01

    The successful vibration reduction of machine tools during machining process can improve productivity, increase quality, and reduce tool wear. This paper will present our initial investigation in the application of smart material technologies in machine tool vibration control using magnetostrictive actuators and electrorheological elastomer dampers on an industrial Sheldon horizontal lathe. The dynamics of the machining process are first studied, which reveals the complexity in the machine tool vibration response and the challenge to the active control techniques. The active control experiment shows encouraging results. The use of electrorheological elastomer damping device for active/passive vibration control provides significant vibration reduction in the high frequency range and great improvement in the workpiece surface finishing. The research presented in this paper demonstrates that the combination of active and active/passive vibration control techniques is very promising for successful machine tool vibration control.

  11. Formal Verification of Effectiveness of Control Activities in Business Processes

    NASA Astrophysics Data System (ADS)

    Arimoto, Yasuhito; Iida, Shusaku; Futatsugi, Kokichi

    It has been an important issue to deal with risks in business processes for achieving companies' goals. This paper introduces a method for applying a formal method to analysis of risks and control activities in business processes in order to evaluate control activities consistently, exhaustively, and to give us potential to have scientific discussion on the result of the evaluation. We focus on document flows in business activities and control activities and risks related to documents because documents play important roles in business. In our method, document flows including control activities are modeled and it is verified by OTS/CafeOBJ Method that risks about falsification of documents are avoided by control activities in the model. The verification is done by interaction between humans and CafeOBJ system with theorem proving, and it raises potential to discuss the result scientifically because the interaction gives us rigorous reasons why the result is derived from the verification.

  12. Active Control of Magnetically Levitated Bearings

    SciTech Connect

    BARNEY, PATRICK S.; LAUFFER, JAMES P.; REDMOND, JAMES M.; SULLIVAN, WILLIAM N.

    2001-03-01

    This report summarizes experimental and test results from a two year LDRD project entitled Real Time Error Correction Using Electromagnetic Bearing Spindles. This project was designed to explore various control schemes for levitating magnetic bearings with the goal of obtaining high precision location of the spindle and exceptionally high rotational speeds. As part of this work, several adaptive control schemes were devised, analyzed, and implemented on an experimental magnetic bearing system. Measured results, which indicated precision positional control of the spindle was possible, agreed reasonably well with simulations. Testing also indicated that the magnetic bearing systems were capable of very high rotational speeds but were still not immune to traditional structural dynamic limitations caused by spindle flexibility effects.

  13. Actively controlled shaft seals for aerospace applications

    NASA Technical Reports Server (NTRS)

    Salant, Richard F.

    1993-01-01

    An electronically controlled mechanical seal for use as the purge gas seal in a liquid oxygen turbo pump has been fabricated and tested under transient operating conditions. The thickness of the lubricating film is controlled by adjusting the coning of the carbon face. This is accomplished by applying a voltage to a piezoelectric actuator to which the carbon face is bonded. The seal has been operated with a closed-loop control system that utilizes either the leakage rate or the seal face temperature as the feedback. Both speed and pressure transients have been imposed on the seal. The transient tests have demonstrated that the seal is capable of maintaining low leakage rates while limiting the face temperatures.

  14. Numerical Investigation of Plasma Active Flow Control

    NASA Astrophysics Data System (ADS)

    Sun, Baigang; Li, Feng; Zhang, Shanshan; Wang, Jingyu; Zhang, Lijuan; Zhao, Erlei

    2010-12-01

    Based on the theory of EHD (electronhydrodynamic), a simplified volume force model is applied to simulation to analyze the traits of plasma flow control in flow field, in which the cold plasma is generated by a DBD (dielectric-barrier-discharge) actuator. With the para-electric action of volume force in electric field, acceleration characteristics of the plasma flow are investigated for different excitation intensities of RF (radio frequency) power for the actuator. Furthermore, the plasma acceleration leads to an asymmetric distribution of flow field, and hence induces the deflection of jet plume, then results in a significant deflection angle of 6.26° thrust-vectoring effect. It appears that the plasma flow control technology is a new tentative method for the thrust-vectoring control of a space vehicle.

  15. Active Flap Control of the SMART Rotor for Vibration Reduction

    NASA Technical Reports Server (NTRS)

    Hall, Steven R.; Anand, R. Vaidyanathan; Straub, Friedrich K.; Lau, Benton H.

    2009-01-01

    Active control methodologies were applied to a full-scale active flap rotor obtained during a joint Boeing/ DARPA/NASA/Army test in the Air Force National Full-Scale Aerodynamic Complex 40- by 80-foot anechoic wind tunnel. The active flap rotor is a full-scale MD 900 helicopter main rotor with each of its five blades modified to include an on-blade piezoelectric actuator-driven flap with a span of 18% of radius, 25% of chord, and located at 83% radius. Vibration control demonstrated the potential of active flaps for effective control of vibratory loads, especially normal force loads. Active control of normal force vibratory loads using active flaps and a continuous-time higher harmonic control algorithm was very effective, reducing harmonic (1-5P) normal force vibratory loads by 95% in both cruise and approach conditions. Control of vibratory roll and pitch moments was also demonstrated, although moment control was less effective than normal force control. Finally, active control was used to precisely control blade flap position for correlation with pretest predictions of rotor aeroacoustics. Flap displacements were commanded to follow specific harmonic profiles of 2 deg or more in amplitude, and the flap deflection errors obtained were less than 0.2 deg r.m.s.

  16. Recent advances in active control of aircraft cabin noise

    NASA Astrophysics Data System (ADS)

    Mathur, Gopal; Fuller, Christopher

    2002-11-01

    Active noise control techniques can provide significant reductions in aircraft interior noise levels without the structural modifications or weight penalties usually associated with passive techniques, particularly for low frequency noise. Our main objective in this presentation is to give a review of active control methods and their applications to aircraft cabin noise reduction with an emphasis on recent advances and challenges facing the noise control engineer in the practical application of these techniques. The active noise control method using secondary acoustic sources, e.g., loudspeakers, as control sources for tonal noise reduction is first discussed with results from an active noise control flight test demonstration. An innovative approach of applying control forces directly to the fuselage structure using piezoelectric actuators, known as active structural acoustic control (ASAC), to control cabin noise is then presented. Experimental results from laboratory ASAC tests conducted on a full-scale fuselage and from flight tests on a helicopter will be discussed. Finally, a hybrid active/passive noise control approach for achieving significant broadband noise reduction will be discussed. Experimental results of control of broadband noise transmission through an aircraft structure will be presented.

  17. Apparent and partial specific adsorption of 1,10-phenanthroline on mixtures of Ca-montmorillonite, activated carbon, and silica gel.

    PubMed

    Ferreiro, Eladio A; de Bussetti, Silvia G

    2005-12-01

    The process of 1,10-phenanthroline adsorption at pH 5 on Ca-montmorillonite, activated carbon, and silica gel mixtures was studied as a function of the equilibrium concentration and the composition of the mixture. A model is presented for determining adsorption of the main component (the variable in the system) of the mixture, based on the thermodynamic concept of apparent and partial quantities, in combination with an equation representing total adsorption of the other two adsorbents as a function of the weight fraction of one of them and introducing the concept of mean total adsorption. The partial specific adsorption of orthophenanthroline (OP) on Ca-montmorillonite is strongly influenced by the presence of activated carbon and silica gel. Owing to a phenomenon of cationic exchange, adsorption on the clay is higher at low proportions in the mixture, but the strong effect of carbon and silica gel becomes apparent at increasing amounts of clay in the mixture. The partial specific adsorption of orthophenanthroline on activated carbon and silica gel was determined using a total adsorption equation for the two adsorbents as a function of the weight fraction of one of them and shows behavior inverse to that of adsorption on clay. PMID:16043188

  18. Acetaldehyde partial oxidation on the Au(111) model catalyst surface: C-C bond activation and formation of methyl acetate as an oxidative coupling product

    NASA Astrophysics Data System (ADS)

    Karatok, Mustafa; Vovk, Evgeny I.; Shah, Asad A.; Turksoy, Abdurrahman; Ozensoy, Emrah

    2015-11-01

    Partial oxidation of acetaldehyde (CH3CHO) on the oxygen pre-covered Au(111) single crystal model catalyst was investigated via Temperature Programmed Desorption (TPD) and Temperature Programmed Reaction Spectroscopy (TPRS) techniques, where ozone (O3) was utilized as the oxygen delivery agent providing atomic oxygen to the reacting surface. We show that for low exposures of O3 and small surface oxygen coverages, two partial oxidation products namely, methyl acetate (CH3COOCH3) and acetic acid (CH3COOH) can be generated without the formation of significant quantities of carbon dioxide. The formation of methyl acetate as the oxidative coupling reaction product implies that oxygen pre-covered Au(111) single crystal model catalyst surface can activate C-C bonds. In addition to the generation of these products; indications of the polymerization of acetaldehyde on the gold surface were also observed as an additional reaction route competing with the partial and total oxidation pathways. The interplay between the partial oxidation, total oxidation and polymerization pathways reveals the complex catalytic chemistry associated with the interaction between the acetaldehyde and atomic oxygen on catalytic gold surfaces.

  19. Pulley With Active Antifriction Actuator And Control

    NASA Technical Reports Server (NTRS)

    Ih, Che-Hang C.; Vivian, Howard C.

    1994-01-01

    Torque actuator and associated control system minimizes effective friction of rotary bearing. Motor exerts compensating torque in response to feedback from external optical sensor. Compensation torque nearly cancels frictional torque of shaft bearings. Also useful in reducing bearing friction in gyro-scopes, galvanometers, torquemeters, accelerometers, earth-motion detectors, and balances.

  20. Selective Activation and Disengagement of Moral Control.

    ERIC Educational Resources Information Center

    Bandura, Albert

    1990-01-01

    Analyzes psychological mechanisms by which moral control is selectively disengaged from inhumane conduct in ordinary and unusual circumstances. Explores the symptoms of moral exclusion as described in the literature. Presents categories that unify theory on moral exclusion and contribute practical classifications for use in empirical studies. (JS)

  1. Active control of cantilever-beam vibration

    NASA Astrophysics Data System (ADS)

    Serbyn, M. Roman

    2002-11-01

    A bang-bang control system previously developed for the stabilization of a rigid platform [ISA Trans. 21, 55-59 (1982)] has been adapted to the problem of reducing flexural vibrations of a beam. The electromechanical system develops an appropriate control signal for the actuator from samples of the disturbance by analog and digital signal processing using integrated circuits. The effectiveness of this approach is predicated upon the sampling rate being much higher than the maximum vibration frequency to be silenced. It is also robust with respect to the waveform of the disturbance. Noise reductions of 10-20 dB have been achieved, depending on the bandwidth of the noise. The cantilever, chosen because of its mechanical and theoretical simplicity, provides a good foundation for the study of more complex structures, like airfoils and nonrigid platforms. In both experimental and analytical investigations the emphasis has been on the optimization of control parameters, particularly with regard to the application of the cancellation signal. Reduction in size and cost of the control unit is possible by incorporating the latest technological advances in electronic and electromechanical devices, such as FPGA boards and MEMS components.

  2. Active fault tolerant control of a flexible beam

    NASA Astrophysics Data System (ADS)

    Bai, Yuanqiang; Grigoriadis, Karolos M.; Song, Gangbing

    2007-04-01

    This paper presents the development and application of an H∞ fault detection and isolation (FDI) filter and fault tolerant controller (FTC) for smart structures. A linear matrix inequality (LMI) formulation is obtained to design the full order robust H∞ filter to estimate the faulty input signals. A fault tolerant H∞ controller is designed for the combined system of plant and filter which minimizes the control objective selected in the presence of disturbances and faults. A cantilevered flexible beam bonded with piezoceramic smart materials, in particular the PZT (Lead Zirconate Titanate), in the form of a patch is used in the validation of the FDI filter and FTC controller design. These PZT patches are surface-bonded on the beam and perform as actuators and sensors. A real-time data acquisition and control system is used to record the experimental data and to implement the designed FDI filter and FTC. To assist the control system design, system identification is conducted for the first mode of the smart structural system. The state space model from system identification is used for the H∞ FDI filter design. The controller was designed based on minimization of the control effort and displacement of the beam. The residuals obtained from the filter through experiments clearly identify the fault signals. The experimental results of the proposed FTC controller show its e effectiveness for the vibration suppression of the beam for the faulty system when the piezoceramic actuator has a partial failure.

  3. Advanced Study for Active Noise Control in Aircraft (ASANCA)

    NASA Technical Reports Server (NTRS)

    Borchers, Ingo U.; Emborg, Urban; Sollo, Antonio; Waterman, Elly H.; Paillard, Jacques; Larsen, Peter N.; Venet, Gerard; Goeransson, Peter; Martin, Vincent

    1992-01-01

    Aircraft interior noise and vibration measurements are included in this paper from ground and flight tests. In addition, related initial noise calculations with and without active noise control are conducted. The results obtained to date indicate that active noise control may be an effective means for reducing the critical low frequency aircraft noise.

  4. An electronic control for an electrohydraulic active control landing gear for the F-4 aircraft

    NASA Technical Reports Server (NTRS)

    Ross, I.

    1982-01-01

    A controller for an electrohydraulic active control landing gear was developed for the F-4 aircraft. A controller was modified for this application. Simulation results indicate that during landing and rollout over repaired bomb craters the active gear effects a force reduction, relative to the passive gear, or approximately 70%.

  5. AMP-Activated Kinase (AMPK) Activation by AICAR in Human White Adipocytes Derived from Pericardial White Adipose Tissue Stem Cells Induces a Partial Beige-Like Phenotype

    PubMed Central

    Abdul-Rahman, Omar; Kristóf, Endre; Doan-Xuan, Quang-Minh; Vida, András; Nagy, Lilla; Horváth, Ambrus; Simon, József; Maros, Tamás; Szentkirályi, István; Palotás, Lehel; Debreceni, Tamás; Csizmadia, Péter; Szerafin, Tamás; Fodor, Tamás; Szántó, Magdolna; Tóth, Attila; Kiss, Borbála; Bacsó, Zsolt; Bai, Péter

    2016-01-01

    Beige adipocytes are special cells situated in the white adipose tissue. Beige adipocytes, lacking thermogenic cues, morphologically look quite similar to regular white adipocytes, but with a markedly different response to adrenalin. White adipocytes respond to adrenergic stimuli by enhancing lipolysis, while in beige adipocytes adrenalin induces mitochondrial biogenesis too. A key step in the differentiation and function of beige adipocytes is the deacetylation of peroxisome proliferator-activated receptor (PPARγ) by SIRT1 and the consequent mitochondrial biogenesis. AMP-activated protein kinase (AMPK) is an upstream activator of SIRT1, therefore we set out to investigate the role of AMPK in beige adipocyte differentiation using human adipose-derived mesenchymal stem cells (hADMSCs) from pericardial adipose tissue. hADMSCs were differentiated to white and beige adipocytes and the differentiation medium of the white adipocytes was supplemented with 100 μM [(2R,3S,4R,5R)-5-(4-Carbamoyl-5-aminoimidazol-1-yl)-3,4-dihydroxyoxolan-2-yl]methyl dihydrogen phosphate (AICAR), a known activator of AMPK. The activation of AMPK with AICAR led to the appearance of beige-like morphological properties in differentiated white adipocytes. Namely, smaller lipid droplets appeared in AICAR-treated white adipocytes in a similar fashion as in beige cells. Moreover, in AICAR-treated white adipocytes the mitochondrial network was more fused than in white adipocytes; a fused mitochondrial system was characteristic to beige adipocytes. Despite the morphological similarities between AICAR-treated white adipocytes and beige cells, functionally AICAR-treated white adipocytes were similar to white adipocytes. We were unable to detect increases in basal or cAMP-induced oxygen consumption rate (a marker of mitochondrial biogenesis) when comparing control and AICAR-treated white adipocytes. Similarly, markers of beige adipocytes such as TBX1, UCP1, CIDEA, PRDM16 and TMEM26 remained the same when

  6. Hybrid Architecture Active Wavefront Sensing and Control

    NASA Technical Reports Server (NTRS)

    Feinberg, Lee; Dean, Bruce; Hyde, Tupper

    2010-01-01

    A method was developed for performing relatively high-speed wavefront sensing and control to overcome thermal instabilities in a segmented primary mirror telescope [e.g., James Webb Space Telescope (JWST) at L2], by using the onboard fine guidance sensor (FGS) to minimize expense and complexity. This FGS performs centroiding on a bright star to feed the information to the pointing and control system. The proposed concept is to beam split the image of the guide star (or use a single defocused guide star image) to perform wavefront sensing using phase retrieval techniques. Using the fine guidance sensor star image for guiding and fine phasing eliminates the need for other, more complex ways of achieving very accurate sensing and control that is needed for UV-optical applications. The phase retrieval occurs nearly constantly, so passive thermal stability over fourteen days is not required. Using the FGS as the sensor, one can feed segment update information to actuators on the primary mirror that can update the primary mirror segment fine phasing with this frequency. Because the thermal time constants of the primary mirror are very slow compared to this duration, the mirror will appear extremely stable during observations (to the level of accuracy of the sensing and control). The sensing can use the same phase retrieval techniques as the JWST by employing an additional beam splitter, and having each channel go through a weak lens (one positive and one negative). The channels can use common or separate detectors. Phase retrieval can be performed onboard. The actuation scheme would include a coarse stage able to achieve initial alignment of several millimeters of range (similar to JWST and can use a JWST heritage sensing approach in the science camera) and a fine stage capable of continual updates.

  7. Active control for turbulent premixed flame simulations

    SciTech Connect

    Bell, John B.; Day, Marcus S.; Grcar, Joseph F.; Lijewski, Michael J.

    2004-03-26

    Many turbulent premixed flames of practical interest are statistically stationary. They occur in combustors that have anchoring mechanisms to prevent blow-off and flashback. The stabilization devices often introduce a level of geometric complexity that is prohibitive for detailed computational studies of turbulent flame dynamics. As a result, typical detailed simulations are performed in simplified model configurations such as decaying isotropic turbulence or inflowing turbulence. In these configurations, the turbulence seen by the flame either decays or, in the latter case, increases as the flame accelerates toward the turbulent inflow. This limits the duration of the eddy evolutions experienced by the flame at a given level of turbulent intensity, so that statistically valid observations cannot be made. In this paper, we apply a feedback control to computationally stabilize an otherwise unstable turbulent premixed flame in two dimensions. For the simulations, we specify turbulent in flow conditions and dynamically adjust the integrated fueling rate to control the mean location of the flame in the domain. We outline the numerical procedure, and illustrate the behavior of the control algorithm. We use the simulations to study the propagation and the local chemical variability of turbulent flame chemistry.

  8. Elements of active vibration control for rotating machinery

    NASA Technical Reports Server (NTRS)

    Ulbrich, Heinz

    1990-01-01

    The success or failure of active vibration control is determined by the availability of suitable actuators, modeling of the entire system including all active elements, positioning of the actuators and sensors, and implementation of problem-adapted control concepts. All of these topics are outlined and their special problems are discussed in detail. Special attention is given to efficient modeling of systems, especially for considering the active elements. Finally, design methods for and the application of active vibration control on rotating machinery are demonstrated by several real applications.

  9. A Hybrid Nonlinear Control Scheme for Active Magnetic Bearings

    NASA Technical Reports Server (NTRS)

    Xia, F.; Albritton, N. G.; Hung, J. Y.; Nelms, R. M.

    1996-01-01

    A nonlinear control scheme for active magnetic bearings is presented in this work. Magnet winding currents are chosen as control inputs for the electromechanical dynamics, which are linearized using feedback linearization. Then, the desired magnet currents are enforced by sliding mode control design of the electromagnetic dynamics. The overall control scheme is described by a multiple loop block diagram; the approach also falls in the class of nonlinear controls that are collectively known as the 'integrator backstepping' method. Control system hardware and new switching power electronics for implementing the controller are described. Various experiments and simulation results are presented to demonstrate the concepts' potentials.

  10. Effect of nacelles on aerodynamic characteristics of an executive-jet model with simulated, partial-chord, laminar-flow-control wing glove

    NASA Technical Reports Server (NTRS)

    Campbell, R. L.

    1982-01-01

    Tests were conducted in the Langley High-Speed 7- by 10-Foot Tunnel using a 1/10-scale model of an executive jet to examine the effects of the nacelles on the wing pressures and model longitudinal aerodynamic characteristics. For the present investigation, each wing panel was modified with a simulated, partial-chord, laminar-flow-control glove. Horizontal-tail effects were also briefly examined. The tests covered a range of Mach numbers from 0.40 to 0.82 and lift coefficients from 0.20 to 0.55. Oil-flow photographs of the wing at selected conditions are included.

  11. Systematic design of membership functions for fuzzy-logic control: A case study on one-stage partial nitritation/anammox treatment systems.

    PubMed

    Boiocchi, Riccardo; Gernaey, Krist V; Sin, Gürkan

    2016-10-01

    A methodology is developed to systematically design the membership functions of fuzzy-logic controllers for multivariable systems. The methodology consists of a systematic derivation of the critical points of the membership functions as a function of predefined control objectives. Several constrained optimization problems corresponding to different qualitative operation states of the system are defined and solved to identify, in a consistent manner, the critical points of the membership functions for the input variables. The consistently identified critical points, together with the linguistic rules, determine the long term reachability of the control objectives by the fuzzy logic controller. The methodology is highlighted using a single-stage side-stream partial nitritation/Anammox reactor as a case study. As a result, a new fuzzy-logic controller for high and stable total nitrogen removal efficiency is designed. Rigorous simulations are carried out to evaluate and benchmark the performance of the controller. The results demonstrate that the novel control strategy is capable of rejecting the long-term influent disturbances, and can achieve a stable and high TN removal efficiency. Additionally, the controller was tested, and showed robustness, against measurement noise levels typical for wastewater sensors. A feedforward-feedback configuration using the present controller would give even better performance. In comparison, a previously developed fuzzy-logic controller using merely expert and intuitive knowledge performed worse. This proved the importance of using a systematic methodology for the derivation of the membership functions for multivariable systems. These results are promising for future applications of the controller in real full-scale plants. Furthermore, the methodology can be used as a tool to help systematically design fuzzy logic control applications for other biological processes. PMID:27390035

  12. Subliminal psychodynamic activation: an experiment controlling for major possible confounding influences outlined by Fudin.

    PubMed

    Gustafson, R; Källmén, H

    1991-08-01

    40 and 48 subjects participated in two separate experiments aimed at reproducing the subliminal psychodynamic activation (SPA) phenomenon and taking into account the major methodological critique by Fudin (1986, 1990). Subjects were first exposed either to a full or one of all possible partial symbiotic messages and then to their anagram equivalents. Confounding and irrelevant influences were controlled; the results indicate that only the full symbiotic message improved motor performance. This strongly suggests that subjects encode the meaning of the full message and supports an interpretation in terms of an alleviation of an internal symbiotic conflict leading to a state of calmness conducive to improved motor performance. PMID:1945681

  13. Enhanced oxidative stress and platelet activation combined with reduced antioxidant capacity in obese prepubertal and adolescent girls with full or partial metabolic syndrome.

    PubMed

    Karamouzis, I; Pervanidou, P; Berardelli, R; Iliadis, S; Papassotiriou, I; Karamouzis, M; Chrousos, G P; Kanaka-Gantenbein, C

    2011-08-01

    In adults, obesity is a main factor implicated in increased oxidative stress (OS), platelet activation (PA) and impaired antioxidant status (AS), all predisposing factors for cardiovascular disease leading to increased morbidity and mortality. Furthermore, the metabolic syndrome (MetS) is an important cardiovascular risk factor, which progressively develops and may already be present during late childhood or adolescence. However, scarce data exist on oxidative-antioxidant balance and PA in childhood and adolescence in the presence of partial (PMetS) or full MetS. The aim of the study was to evaluate OS, PA, and AS in prepubertal and adolescent obese girls with partial or full MetS. 96 girls with a clinical and metabolic evaluation for obesity and 44 healthy normal-weight sex- and age-matched girls were studied. IDF-adopted criteria were used to define full and partial MetS and the patient population was divided into 4 groups: the first comprised 31 pre-pubertal girls with PMetS (PR-PMetS), the second 37 adolescents with PMetS (AD-PMetS), the third 10 prepubertal girls with full MetS (PR-MetS), and the fourth 18 adolescents with full MetS (AD-MetS). The OS was evaluated by measuring plasma 15-F(2t)-Isoprostane levels (15-F(2t)-IsoP) and protein carbonyls, PA by thromboxane B(2) levels (TXB(2)), and AS by serum vitamin E and plasma total antioxidant capacity (TAC) levels. 15-F(2t)-IsoP, protein carbonyls, and TXB(2) levels were significantly gradually amplified, and vitamin E and TAC reduced, and significantly correlated with obesity from childhood to adolescence and from partial to full MetS. This study demonstrates the loss of the normal homeostatic balance between oxidant-antioxidant state in obese children and adolescents with manifestations of partial and full MetS. PMID:21823055

  14. An active control synchronization for two modified Chua circuits

    NASA Astrophysics Data System (ADS)

    Li, Guo-Hui

    2005-03-01

    From modern control theory, an active control method to synchronize two modified Chua circuits with each other, which exhibit chaos, is presented. Some sufficient conditions of linear stability of the chaotic synchronization are obtained from rigorous mathematic justification. On the basis of the state-observer, the controller is analytically deduced using the active control. It is shown that this technique can be applied to achieve synchronization of the two systems with each other, whether they are identical or not. Finally, numerical simulations show the effectiveness of the proposed control scheme.

  15. External locus of control contributes to racial disparities in memory and reasoning training gains in ACTIVE.

    PubMed

    Zahodne, Laura B; Meyer, Oanh L; Choi, Eunhee; Thomas, Michael L; Willis, Sherry L; Marsiske, Michael; Gross, Alden L; Rebok, George W; Parisi, Jeanine M

    2015-09-01

    Racial disparities in cognitive outcomes may be partly explained by differences in locus of control. African Americans report more external locus of control than non-Hispanic Whites, and external locus of control is associated with poorer health and cognition. The aims of this study were to compare cognitive training gains between African American and non-Hispanic White participants in the Advanced Cognitive Training for Independent and Vital Elderly (ACTIVE) study and determine whether racial differences in training gains are mediated by locus of control. The sample comprised 2,062 (26% African American) adults aged 65 and older who participated in memory, reasoning, or speed training. Latent growth curve models evaluated predictors of 10-year cognitive trajectories separately by training group. Multiple group modeling examined associations between training gains and locus of control across racial groups. Compared to non-Hispanic Whites, African Americans evidenced less improvement in memory and reasoning performance after training. These effects were partially mediated by locus of control, controlling for age, sex, education, health, depression, testing site, and initial cognitive ability. African Americans reported more external locus of control, which was associated with smaller training gains. External locus of control also had a stronger negative association with reasoning training gain for African Americans than for Whites. No racial difference in training gain was identified for speed training. Future intervention research with African Americans should test whether explicitly targeting external locus of control leads to greater cognitive improvement following cognitive training. PMID:26237116

  16. External locus of control contributes to racial disparities in memory and reasoning training gains in ACTIVE

    PubMed Central

    Zahodne, Laura B.; Meyer, Oanh L.; Choi, Eunhee; Thomas, Michael L.; Willis, Sherry L.; Marsiske, Michael; Gross, Alden L.; Rebok, George W.; Parisi, Jeanine M.

    2015-01-01

    Racial disparities in cognitive outcomes may be partly explained by differences in locus of control. African Americans report more external locus of control than non-Hispanic Whites, and external locus of control is associated with poorer health and cognition. The aims of this study were to compare cognitive training gains between African American and non-Hispanic White participants in the Advanced Cognitive Training for Independent and Vital Elderly (ACTIVE) study and determine whether racial differences in training gains are mediated by locus of control. The sample comprised 2,062 (26% African American) adults aged 65 and older who participated in memory, reasoning, or speed training. Latent growth curve models evaluated predictors of 10-year cognitive trajectories separately by training group. Multiple group modeling examined associations between training gains and locus of control across racial groups. Compared to non-Hispanic Whites, African Americans evidenced less improvement in memory and reasoning performance after training. These effects were partially mediated by locus of control, controlling for age, sex, education, health, depression, testing site, and initial cognitive ability. African Americans reported more external locus of control, which was associated with smaller training gains. External locus of control also had a stronger negative association with reasoning training gain for African Americans than for Whites. No racial difference in training gain was identified for speed training. Future intervention research with African Americans should test whether explicitly targeting external locus of control leads to greater cognitive improvement following cognitive training. PMID:26237116

  17. Active control of compressible flows on a curved surface

    NASA Technical Reports Server (NTRS)

    Maestrello, L.; Parikh, P.; Bayliss, A.; Turkel, E.

    1985-01-01

    The effect of localized, time periodic surface heating and cooling over a curved surface is studied. This is a mechanism for the active control of unstable disturbances by phase cancellation and reinforcement. It is shown that the pressure gradient induced by the curvature significantly enhances the effectiveness of this form of active control. In particular, by appropriate choice of phase, active surface heating can completely stabilize and unstable wave.

  18. Generalized internal model robust control for active front steering intervention

    NASA Astrophysics Data System (ADS)

    Wu, Jian; Zhao, Youqun; Ji, Xuewu; Liu, Yahui; Zhang, Lipeng

    2015-03-01

    Because of the tire nonlinearity and vehicle's parameters' uncertainties, robust control methods based on the worst cases, such as H ∞, µ synthesis, have been widely used in active front steering control, however, in order to guarantee the stability of active front steering system (AFS) controller, the robust control is at the cost of performance so that the robust controller is a little conservative and has low performance for AFS control. In this paper, a generalized internal model robust control (GIMC) that can overcome the contradiction between performance and stability is used in the AFS control. In GIMC, the Youla parameterization is used in an improved way. And GIMC controller includes two sections: a high performance controller designed for the nominal vehicle model and a robust controller compensating the vehicle parameters' uncertainties and some external disturbances. Simulations of double lane change (DLC) maneuver and that of braking on split- µ road are conducted to compare the performance and stability of the GIMC control, the nominal performance PID controller and the H ∞ controller. Simulation results show that the high nominal performance PID controller will be unstable under some extreme situations because of large vehicle's parameters variations, H ∞ controller is conservative so that the performance is a little low, and only the GIMC controller overcomes the contradiction between performance and robustness, which can both ensure the stability of the AFS controller and guarantee the high performance of the AFS controller. Therefore, the GIMC method proposed for AFS can overcome some disadvantages of control methods used by current AFS system, that is, can solve the instability of PID or LQP control methods and the low performance of the standard H ∞ controller.

  19. Partial Activation and Inhibition of TRPV1 Channels by Evodiamine and Rutaecarpine, Two Major Components of the Fruits of Evodia rutaecarpa.

    PubMed

    Wang, Shenglan; Yamamoto, Satoshi; Kogure, Yoko; Zhang, Wensheng; Noguchi, Koichi; Dai, Yi

    2016-05-27

    Evodiamine (1) and rutaecarpine (2) are the two major components of Evodia rutaecarpa, which has long been used in traditional medicine for the treatment of many diseases. Using transient receptor potential vanilloid 1 (TRPV1)-expressing HEK293 cells and patch-clamp recording, the inhibitory actions of 1 and 2 against TRPV1 channels were investigated. The effects of these compounds against capsaicin- or proton-activated TRPV1 activities were evaluated. The results showed that, although 1 and 2 can activate TRPV1, the maximum response was 3.5- or 9-fold lower than that of capsaicin, respectively, suggesting partial agonism. In comparison to capsaicin, coadministration of 1 and capsaicin increased the half-maximal effective concentration (EC50) of capsaicin-activated TRPV1 currents as shown by a right shift in the dose-response curve, whereas coadministration of 1 with protons failed to inhibit the proton-induced current. Moreover, preadministration of 1, but not 2, inhibited both capsaicin- and proton-induced TRPV1 currents, which might involve channel desensitization. Taken together, 1 and 2 may share the same binding site with capsaicin and act as partial agonists (antagonists) of TRPV1. Evodiamine (1), but not rutaecarpine (2), can desensitize or competitively inhibit the activity of TRPV1. PMID:27159637

  20. Controlling interneuron activity in Caenorhabditis elegans to evoke chemotactic behaviour.

    PubMed

    Kocabas, Askin; Shen, Ching-Han; Guo, Zengcai V; Ramanathan, Sharad

    2012-10-11

    Animals locate and track chemoattractive gradients in the environment to find food. With its small nervous system, Caenorhabditis elegans is a good model system in which to understand how the dynamics of neural activity control this search behaviour. Extensive work on the nematode has identified the neurons that are necessary for the different locomotory behaviours underlying chemotaxis through the use of laser ablation, activity recording in immobilized animals and the study of mutants. However, we do not know the neural activity patterns in C. elegans that are sufficient to control its complex chemotactic behaviour. To understand how the activity in its interneurons coordinate different motor programs to lead the animal to food, here we used optogenetics and new optical tools to manipulate neural activity directly in freely moving animals to evoke chemotactic behaviour. By deducing the classes of activity patterns triggered during chemotaxis and exciting individual neurons with these patterns, we identified interneurons that control the essential locomotory programs for this behaviour. Notably, we discovered that controlling the dynamics of activity in just one interneuron pair (AIY) was sufficient to force the animal to locate, turn towards and track virtual light gradients. Two distinct activity patterns triggered in AIY as the animal moved through the gradient controlled reversals and gradual turns to drive chemotactic behaviour. Because AIY neurons are post-synaptic to most chemosensory and thermosensory neurons, it is probable that these activity patterns in AIY have an important role in controlling and coordinating different taxis behaviours of the animal. PMID:23000898

  1. Active laser system for sea ice control

    NASA Astrophysics Data System (ADS)

    Evtikhiev, Nickolay N.; Gaponov, Alexandr E.; Kuluba, Yury N.; Matous, Vladislav I.; Radominov, Oleg E.; Tuzikov, Vladimir Z.; Vargaftic, Vasiliy N.

    1997-01-01

    The airborne systems are used for complex investigations of coastline very successfully, for example it can be used to measure the depth of the sea, to discover the reefs and so on. Such information may be used in navigation too. The specific conditions of navigation in the North and Pole seas defines the necessity of exact knowledge about the ice cracks in order to find the possible direction of the ship movement. The active optical system, working in the near IR region, has many advantages before the passive one, especially if it is necessary to work during the polar night and at bad weather conditions. In this article we discuss the demands to the laser active airborne systems, that given the accurate picture of the ice with high resolution in the daytime and nighttime conditions. Such system based on the laser, mechanical scanner and avalanche photodiode is very compact, reliable and informative. The picture of the ice surface can be shown on the TV monitor, can be written to the memory and can be delivered to the processing center by the radiochannel. The experimental results are shown together with results of this system probing in the conditions of the North Pole Ocean.

  2. A Study of a Two Stage Maximum Power Point Tracking Control of a Photovoltaic System under Partially Shaded Insolation Conditions

    NASA Astrophysics Data System (ADS)

    Kobayashi, Kenji; Takano, Ichiro; Sawada, Yoshio

    A photovoltaic array shows relatively low output power density, and has a greatly drooping Current-Voltage (I-V) characteristic. Therefore, Maximum Power Point Tracking (MPPT) control is used to maximize the output power of the array. Many papers have been reported in relation to MPPT. However, the Current-Power (I-P) curve sometimes shows multi-local maximum points mode under non-uniform insolation conditions. The operating point of the PV system tends to converge to a local maximum output point which is not the real maximal output point on the I-P curve. Some papers have been also reported, trying to avoid this difficulty. However most of those control systems become rather complicated. Then, the two stage MPPT control method is proposed in this paper to realize a relatively simple control system which can track the real maximum power point even under non-uniform insolation conditions. The feasibility of this control concept is confirmed for steady insolation as well as for rapidly changing insolation by simulation study using software PSIM and LabVIEW. In addition, simulated experiment confirms fundament al operation of the two stage MPPT control.

  3. Study of tethered satellite active attitude control

    NASA Technical Reports Server (NTRS)

    Colombo, G.

    1982-01-01

    Existing software was adapted for the study of tethered subsatellite rotational dynamics, an analytic solution for a stable configuration of a tethered subsatellite was developed, the analytic and numerical integrator (computer) solutions for this "test case' was compared in a two mass tether model program (DUMBEL), the existing multiple mass tether model (SKYHOOK) was modified to include subsatellite rotational dynamics, the analytic "test case,' was verified, and the use of the SKYHOOK rotational dynamics capability with a computer run showing the effect of a single off axis thruster on the behavior of the subsatellite was demonstrated. Subroutines for specific attitude control systems are developed and applied to the study of the behavior of the tethered subsatellite under realistic on orbit conditions. The effect of all tether "inputs,' including pendular oscillations, air drag, and electrodynamic interactions, on the dynamic behavior of the tether are included.

  4. Combustion diagnostic for active engine feedback control

    DOEpatents

    Green, Jr., Johney Boyd; Daw, Charles Stuart; Wagner, Robert Milton

    2007-10-02

    This invention detects the crank angle location where combustion switches from premixed to diffusion, referred to as the transition index, and uses that location to define integration limits that measure the portions of heat released during the combustion process that occur during the premixed and diffusion phases. Those integrated premixed and diffusion values are used to develop a metric referred to as the combustion index. The combustion index is defined as the integrated diffusion contribution divided by the integrated premixed contribution. As the EGR rate is increased enough to enter the low temperature combustion regime, PM emissions decrease because more of the combustion process is occurring over the premixed portion of the heat release rate profile and the diffusion portion has been significantly reduced. This information is used to detect when the engine is or is not operating in a low temperature combustion mode and provides that feedback to an engine control algorithm.

  5. Active control system for high speed windmills

    DOEpatents

    Avery, D.E.

    1988-01-12

    A pump stroke is matched to the operating speed of a high speed windmill. The windmill drives a hydraulic pump for a control. Changes in speed of a wind driven shaft open supply and exhaust valves to opposite ends of a hydraulic actuator to lengthen and shorten an oscillating arm thereby lengthening and shortening the stroke of an output pump. Diminishing wind to a stall speed causes the valves to operate the hydraulic cylinder to shorten the oscillating arm to zero. A pressure accumulator in the hydraulic system provides the force necessary to supply the hydraulic fluid under pressure to drive the actuator into and out of the zero position in response to the windmill shaft speed approaching and exceeding windmill stall speed. 4 figs.

  6. Active control system for high speed windmills

    DOEpatents

    Avery, Don E.

    1988-01-01

    A pump stroke is matched to the operating speed of a high speed windmill. The windmill drives a hydraulic pump for a control. Changes in speed of a wind driven shaft open supply and exhaust valves to opposite ends of a hydraulic actuator to lengthen and shorten an oscillating arm thereby lengthening and shortening the stroke of an output pump. Diminishing wind to a stall speed causes the valves to operate the hydraulic cylinder to shorten the oscillating arm to zero. A pressure accumulator in the hydraulic system provides the force necessary to supply the hydraulic fluid under pressure to drive the actuator into and out of the zero position in response to the windmill shaft speed approaching and exceeding windmill stall speed.

  7. A quantitative structure-activity relationship to predict efficacy of granular activated carbon adsorption to control emerging contaminants.

    PubMed

    Kennicutt, A R; Morkowchuk, L; Krein, M; Breneman, C M; Kilduff, J E

    2016-08-01

    A quantitative structure-activity relationship was developed to predict the efficacy of carbon adsorption as a control technology for endocrine-disrupting compounds, pharmaceuticals, and components of personal care products, as a tool for water quality professionals to protect public health. Here, we expand previous work to investigate a broad spectrum of molecular descriptors including subdivided surface areas, adjacency and distance matrix descriptors, electrostatic partial charges, potential energy descriptors, conformation-dependent charge descriptors, and Transferable Atom Equivalent (TAE) descriptors that characterize the regional electronic properties of molecules. We compare the efficacy of linear (Partial Least Squares) and non-linear (Support Vector Machine) machine learning methods to describe a broad chemical space and produce a user-friendly model. We employ cross-validation, y-scrambling, and external validation for quality control. The recommended Support Vector Machine model trained on 95 compounds having 23 descriptors offered a good balance between good performance statistics, low error, and low probability of over-fitting while describing a wide range of chemical features. The cross-validated model using a log-uptake (qe) response calculated at an aqueous equilibrium concentration (Ce) of 1 μM described the training dataset with an r(2) of 0.932, had a cross-validated r(2) of 0.833, and an average residual of 0.14 log units. PMID:27586364

  8. Control of sound radiation with active/adaptive structures

    NASA Technical Reports Server (NTRS)

    Fuller, C. R.; Rogers, C. A.; Robertshaw, H. H.

    1992-01-01

    Recent research is discussed in the area of active structural acoustic control with active/adaptive structures. Progress in the areas of structural acoustics, actuators, sensors, and control approaches is presented. Considerable effort has been given to the interaction of these areas with each other due to the coupled nature of the problem. A discussion is presented on actuators bonded to or embedded in the structure itself. The actuators discussed are piezoceramic actuators and shape memory alloy actuators. The sensors discussed are optical fiber sensors, Nitinol fiber sensors, piezoceramics, and polyvinylidene fluoride sensors. The active control techniques considered are state feedback control techniques and least mean square adaptive algorithms. Results presented show that significant progress has been made towards controlling structurally radiated noise by active/adaptive means applied directly to the structure.

  9. Numerical evaluation of the performance of active noise control systems

    NASA Technical Reports Server (NTRS)

    Mollo, C. G.; Bernhard, R. J.

    1990-01-01

    This paper presents a generalized numerical technique for evaluating the optimal performance of active noise controllers. In this technique, the indirect BEM numerical procedures are used to derive the active noise controllers for optimal control of enclosed harmonic sound fields where the strength of the noise sources or the description of the enclosure boundary may not be known. The performance prediction for a single-input single-output system is presented, together with the analysis of the stability and observability of an active noise-control system employing detectors. The numerical procedures presented can be used for the design of both the physical configuration and the electronic components of the optimal active noise controller.

  10. Adaptive Actor-Critic Design-Based Integral Sliding-Mode Control for Partially Unknown Nonlinear Systems With Input Disturbances.

    PubMed

    Fan, Quan-Yong; Yang, Guang-Hong

    2016-01-01

    This paper is concerned with the problem of integral sliding-mode control for a class of nonlinear systems with input disturbances and unknown nonlinear terms through the adaptive actor-critic (AC) control method. The main objective is to design a sliding-mode control methodology based on the adaptive dynamic programming (ADP) method, so that the closed-loop system with time-varying disturbances is stable and the nearly optimal performance of the sliding-mode dynamics can be guaranteed. In the first step, a neural network (NN)-based observer and a disturbance observer are designed to approximate the unknown nonlinear terms and estimate the input disturbances, respectively. Based on the NN approximations and disturbance estimations, the discontinuous part of the sliding-mode control is constructed to eliminate the effect of the disturbances and attain the expected equivalent sliding-mode dynamics. Then, the ADP method with AC structure is presented to learn the optimal control for the sliding-mode dynamics online. Reconstructed tuning laws are developed to guarantee the stability of the sliding-mode dynamics and the convergence of the weights of critic and actor NNs. Finally, the simulation results are presented to illustrate the effectiveness of the proposed method. PMID:26357411

  11. Wireless sensor networks for active vibration control in automobile structures

    NASA Astrophysics Data System (ADS)

    Mieyeville, Fabien; Ichchou, Mohamed; Scorletti, Gérard; Navarro, David; Du, Wan

    2012-07-01

    Wireless sensor networks (WSNs) are nowadays widely used in monitoring and tracking applications. This paper presents the feasibility of using WSNs in active vibration control strategies. The method employed here involves active-structural acoustic control using piezoelectric sensors distributed on a car structure. This system aims at being merged with a WSN whose head node collects data and processes control laws so as to command piezoelectric actuators wisely placed on the structure. We will study the feasibility of implementing WSNs in active vibration control and introduce a complete design methodology to optimize hardware/software and control law synergy in mechatronic systems. A design space exploration will be conducted so as to identify the best WSN platform and the resulting impact on control.

  12. Morphology and gas sensing characteristics of density-controlled CuO nanostructures obtained by varying the oxygen partial pressure during growth

    NASA Astrophysics Data System (ADS)

    Lee, Dongjin; Jin, Changhyun; Noh, Youngwook; Park, Seokhyun; Choi, Sun-Woo

    2016-07-01

    By exerting different O2 partial pressures (0, 20, 40, and 60 sccm) onto copper substrates, we discovered that the growth parameter, namely, the O2 flow rate, affects the degree of nucleation, diameter, length, and crystalline quality of CuO nanowires (NWs). Scanning electron microscopy (SEM), X-ray diffraction (XRD), and transmission electron microscopy (TEM) were used to analyze the evolution of the morphological and the microstructural changes in the CuO nanostructures. The formation of a Cu2O interlayer between the Cu and the CuO layers could be adjusted by controlling more precisely the O2 flow rate. In addition, the reducing (H2S) and the oxidizing (O2, NO2, and SO2) gas sensing performances of these O2-assisted CuO NWs were compared with those of CuO NWs grown in static air. The response to the reducing H2S of the sensors based on CuO NWs grown using O2 at 40 sccm showed a higher electrical change and faster response and recovery times than the sensors based on CuO NWs grown using lower O2 flow rates, including the ones grown in static air and/or used for sensing oxidizing gases (O2, NO2, and SO2) did. On the basis of their growth and their gas-sensing applications, the possible mechanisms characteristic of the density-controlled CuO NWs grown using various O2 partial pressures are discussed.

  13. Start up partial nitrification at low temperature with a real-time control strategy based on blower frequency and pH.

    PubMed

    Gu, Shengbo; Wang, Shuying; Yang, Qing; Yang, Pei; Peng, Yongzhen

    2012-05-01

    In this study, the performance of partial nitrification via nitrite at low temperature was investigated in a pilot-scale sequencing batch reactor (SBR) with a working volume of 7.0m(3). A novel real-time control strategy, based on blower frequency (BF) and pH, was designed and evaluated. The nitrogen break point (NBP) in the BF curve and the nitrate/nitrite apex point (NAP) in the pH curve were used to identify the endpoint of the aerobic and anoxic phases, respectively. The nitrite accumulation rate (NAR) rapidly increased from 19.8% to 90%. Partial nitrification was achieved at low temperature (11-16°C) in 40 days and was stably maintained for as long as 140 days by applying a real-time control strategy based on pH and BF. Fluorescence in situ hybirdization (FISH) results demonstrated that ammonia oxidation bacteria (AOB) had developed into the dominant nitrifying bacteria compared to nitrite oxidation bacteria (NOB) in the system. PMID:22414573

  14. Imprinted control of gene activity in Drosophila.

    PubMed

    Golic, K G; Golic, M M; Pimpinelli, S

    1998-11-19

    Genetic imprinting is defined as a reversible, differential marking of genes or chromosomes that is determined by the sex of the parent from whom the genetic material is inherited [1]. Imprinting was first observed in insects where, in some species, most notably among the coccoids (scale insects and allies), the differential marking of paternally and maternally transmitted chromosome sets leads to inactivation or elimination of paternal chromosomes [2]. Imprinting is also widespread in plants and mammals [3,4], in which paternally and maternally inherited alleles may be differentially expressed. Despite imprinting having been discovered in insects, clear examples of parental imprinting are scarce in the model insect species Drosophila melanogaster. We describe a case of imprint-mediated control of gene expression in Drosophila. The imprinted gene - the white+ eye-color gene - is expressed at a low level when transmitted by males, and at a high level when transmitted by females. Thus, in common with coccoids, Drosophila is capable of generating an imprint, and can respond to that imprint by silencing the paternal allele. PMID:9822579

  15. Various applications of Active Field Control (AFC)

    NASA Astrophysics Data System (ADS)

    Watanabe, Takayuki; Miyazaki, Hideo; Kishinaga, Shinji; Kawakami, Fukushi

    2003-10-01

    AFC is an electro-acoustic enhancement system, which has been under development at Yamaha Corporation. In this paper, several types of various AFC applications are discussed, while referring to representative projects for each application in Japan. (1) Realization of acoustics in a huge hall to classical music program, e.g., Tokyo International Forum. This venue is a multipurpose hall with approximately 5000 seats. AFC achieves loudness and reverberance equivalent to those of a hall with 2500 seats or fewer. (2) Optimization of acoustics for a variety of programs, e.g., Arkas Sasebo. AFC is used to create the optimum acoustics for each program, such as reverberance for classical concerts, acoustical support for opera singers, uniformity throughout the hall from the stage to under-balcony area, etc. (3) Control of room shape acoustical effect, e.g., Osaka Central Public Hall: In this renovation project, preservation of historically important architecture in the original form is required. AFC is installed to vary only the acoustical environment without architectural changes. (4) Assistance with crowd enthusiasm for sports entertainment, e.g., Tokyo Metropolitan Gymnasium. In this venue, which is designed as a very absorptive space for speech intelligibility, AFC is installed to enhance the atmosphere of live sports entertainment.

  16. Size-dependent selectivity and activity of silver nanoclusters in the partial oxidation of propylene to propylene oxide and acrolein : A joint experimental and theoretical study.

    SciTech Connect

    Molina, L M.; Lee, S.; Sell, K.; Barcaro, G.; Fortunelli, A.; Lee, B.; Seifert, S.; Winans, R. E.; Elam, J. W.; Pellin, M. J.; Barke, I.; von Oeynhausen, V.; Lei, Y.; Meyer, R. J.; Alonso, J. A.; Fraile-Rodriguez, A.; Kleibert, A.; Giorgio, S.; Henry, C. R.; Heinz Meiwes-Broer, K.; Vadja, S.; Univ. de Valladolid; Univ. Rostock; IPCF-CNR; Univ. of Illinois at Chicago; Swiss Light Source; CINaM-CNRS and Aix-Marseille Univ.; Yale Univ.

    2011-02-02

    Model silver nanocatalysts between 9 and 23 nm in size were prepared by size-selected cluster deposition from a free cluster beam on amorphous alumina films and their size-dependent catalytic performance studied in the partial oxidation of propylene under realistic reaction conditions. Smaller clusters preferentially produced acrolein, while the 23 nm particles were considerably more selective towards the formation of propylene oxide, at reaction rates far exceeding those previously reported for larger silver particles. The activity of clusters dropped significantly with increasing particle size. First-principle calculations, of the activation energies for oxygen adsorption and its dissociation, at variable surface coverage yielded surface energies which resulted in particle shapes resembling the experimentally observed shapes of partially oxidized silver clusters. The calculated activation barriers for propylene oxide and acrolein formation on various facets and on the edges of the nanoparticles provided detailed information about the energetics of the competing reaction pathways. The size- and corresponding morphology dependent theoretical activity and selectivity are in good accord with experimental observations.

  17. 78 FR 77419 - Certain Activated Carbon From the People's Republic of China; 2012-2013; Partial Rescission of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-12-23

    ... International Trade Administration Certain Activated Carbon From the People's Republic of China; 2012-2013... administrative review of the antidumping duty order on certain activated carbon from the People's Republic of... activated carbon from the PRC (``the Order'').\\1\\ Based upon these requests, on June 3, 2013, the...

  18. Distributed piezoelectric vibration control for a flexible-link manipulator based on an observer in the form of partial differential equations

    NASA Astrophysics Data System (ADS)

    Yang, Hongjun; Liu, Jinkun

    2016-02-01

    This paper mainly focuses on designing a distributed observer-based controller for a flexible-link manipulator bonded with piezoelectric actuators. The dynamic model of the link can be taken as an Euler-Bernoulli beam and takes on the form of partial differential equations (PDEs). The proposed observer, which is proven exponentially stable, has the ability to estimate infinite dimensional states, and only the boundary practical measurement values are needed. A novel distributed observer-based controller is subsequently developed to make the joint position track a desired trajectory and rapidly regulate vibrations on the whole beam, which is the main contribution of the paper. The closed-loop system is guaranteed exponentially stable by theoretical analysis and its favorable performance is demonstrated by numerical simulations.

  19. On-line Monitoring and Active Control for Transformer Noise

    NASA Astrophysics Data System (ADS)

    Liang, Jiabi; Zhao, Tong; Tian, Chun; Wang, Xia; He, Zhenhua; Duan, Lunfeng

    This paper introduces the system for on-line monitoring and active noise control towards the transformer noise based on LabVIEW and the hardware equipment including the hardware and software. For the hardware part, it is mainly focused on the composition and the role of hardware devices, as well as the mounting location in the active noise control experiment. And the software part introduces the software flow chats, the measurement and analysis module for the sound pressure level including A, B, C weighting methods, the 1/n octave spectrum and the power spectrum, active noise control module and noise data access module.

  20. [Actuator placement for active sound and vibration control

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Two refereed journal publications and ten talks given at conferences, seminars, and colloquia resulted from research supported by NASA. They are itemized in this report. The two publications were entitled "Reactive Tabu and Search Sensor Selection in Active Structural Acoustic Control Problems" and "Quelling Cabin Noise in Turboprop Aircraft via Active Control." The conference presentations covered various aspects of actuator placement, including location problems, for active sound and vibration control of cylinders, of commuter jets, of propeller driven or turboprop aircraft, and for quelling aircraft cabin or interior noise.

  1. Active airborne contamination control using electrophoresis

    SciTech Connect

    Veatch, B.D.

    1994-06-01

    In spite of our best efforts, radioactive airborne contamination continues to be a formidable problem at many of the Department of Energy (DOE) weapons complex sites. For workers that must enter areas with high levels of airborne contamination, personnel protective equipment (PPE) can become highly restrictive, greatly diminishing productivity. Rather than require even more restrictive PPE for personnel in some situations, the Rocky Flats Plant (RFP) is actively researching and developing methods to aggressively combat airborne contamination hazards using electrophoretic technology. With appropriate equipment, airborne particulates can be effectively removed and collected for disposal in one simple process. The equipment needed to implement electrophoresis is relatively inexpensive, highly reliable, and very compact. Once airborne contamination levels are reduced, less PPE is required and a significant cost savings may be realized through decreased waste and maximized productivity. Preliminary ``cold,`` or non-radioactive, testing results at the RFP have shown the technology to be effective on a reasonable scale, with several potential benefits and an abundance of applications.

  2. Methanol partial oxidation reformer

    DOEpatents

    Ahmed, S.; Kumar, R.; Krumpelt, M.

    1999-08-17

    A partial oxidation reformer is described comprising a longitudinally extending chamber having a methanol, water and an air inlet and an outlet. An igniter mechanism is near the inlets for igniting a mixture of methanol and air, while a partial oxidation catalyst in the chamber is spaced from the inlets and converts methanol and oxygen to carbon dioxide and hydrogen. Controlling the oxygen to methanol mole ratio provides continuous slightly exothermic partial oxidation reactions of methanol and air producing hydrogen gas. The liquid is preferably injected in droplets having diameters less than 100 micrometers. The reformer is useful in a propulsion system for a vehicle which supplies a hydrogen-containing gas to the negative electrode of a fuel cell. 7 figs.

  3. Methanol partial oxidation reformer

    DOEpatents

    Ahmed, Shabbir; Kumar, Romesh; Krumpelt, Michael

    1999-01-01

    A partial oxidation reformer comprising a longitudinally extending chamber having a methanol, water and an air inlet and an outlet. An igniter mechanism is near the inlets for igniting a mixture of methanol and air, while a partial oxidation catalyst in the chamber is spaced from the inlets and converts methanol and oxygen to carbon dioxide and hydrogen. Controlling the oxygen to methanol mole ratio provides continuous slightly exothermic partial oxidation reactions of methanol and air producing hydrogen gas. The liquid is preferably injected in droplets having diameters less than 100 micrometers. The reformer is useful in a propulsion system for a vehicle which supplies a hydrogen-containing gas to the negative electrode of a fuel cell.

  4. Methanol partial oxidation reformer

    DOEpatents

    Ahmed, Shabbir; Kumar, Romesh; Krumpelt, Michael

    2001-01-01

    A partial oxidation reformer comprising a longitudinally extending chamber having a methanol, water and an air inlet and an outlet. An igniter mechanism is near the inlets for igniting a mixture of methanol and air, while a partial oxidation catalyst in the chamber is spaced from the inlets and converts methanol and oxygen to carbon dioxide and hydrogen. Controlling the oxygen to methanol mole ratio provides continuous slightly exothermic partial oxidation reactions of methanol and air producing hydrogen gas. The liquid is preferably injected in droplets having diameters less than 100 micrometers. The reformer is useful in a propulsion system for a vehicle which supplies a hydrogen-containing gas to the negative electrode of a fuel cell.

  5. Methanol partial oxidation reformer

    DOEpatents

    Ahmed, S.; Kumar, R.; Krumpelt, M.

    1999-08-24

    A partial oxidation reformer is described comprising a longitudinally extending chamber having a methanol, water and an air inlet and an outlet. An igniter mechanism is near the inlets for igniting a mixture of methanol and air, while a partial oxidation catalyst in the chamber is spaced from the inlets and converts methanol and oxygen to carbon dioxide and hydrogen. Controlling the oxygen to methanol mole ratio provides continuous slightly exothermic partial oxidation reactions of methanol and air producing hydrogen gas. The liquid is preferably injected in droplets having diameters less than 100 micrometers. The reformer is useful in a propulsion system for a vehicle which supplies a hydrogen-containing gas to the negative electrode of a fuel cell. 7 figs.

  6. Controlling the corrosion and cathodic activation of magnesium via microalloying additions of Ge

    NASA Astrophysics Data System (ADS)

    Liu, R. L.; Hurley, M. F.; Kvryan, A.; Williams, G.; Scully, J. R.; Birbilis, N.

    2016-06-01

    The evolution of corrosion morphology and kinetics for magnesium (Mg) have been demonstrated to be influenced by cathodic activation, which implies that the rate of the cathodic partial reaction is enhanced as a result of anodic dissolution. This phenomenon was recently demonstrated to be moderated by the use of arsenic (As) alloying as a poison for the cathodic reaction, leading to significantly improved corrosion resistance. The pursuit of alternatives to toxic As is important as a means to imparting a technologically safe and effective corrosion control method for Mg (and its alloys). In this work, Mg was microalloyed with germanium (Ge), with the aim of improving corrosion resistance by retarding cathodic activation. Based on a combined analysis herein, we report that Ge is potent in supressing the cathodic hydrogen evolution reaction (reduction of water) upon Mg, improving corrosion resistance. With the addition of Ge, cathodic activation of Mg subject to cyclic polarisation was also hindered, with beneficial implications for future Mg electrodes.

  7. The aircraft energy efficiency active controls technology program

    NASA Technical Reports Server (NTRS)

    Hood, R. V., Jr.

    1977-01-01

    Broad outlines of the NASA Aircraft Energy Efficiency Program for expediting the application of active controls technology to civil transport aircraft are presented. Advances in propulsion and airframe technology to cut down on fuel consumption and fuel costs, a program for an energy-efficient transport, and integrated analysis and design technology in aerodynamics, structures, and active controls are envisaged. Fault-tolerant computer systems and fault-tolerant flight control system architectures are under study. Contracts with leading manufacturers for research and development work on wing-tip extensions and winglets for the B-747, a wing load alleviation system, elastic mode suppression, maneuver-load control, and gust alleviation are mentioned.

  8. Active controls: A look at analytical methods and associated tools

    NASA Technical Reports Server (NTRS)

    Newsom, J. R.; Adams, W. M., Jr.; Mukhopadhyay, V.; Tiffany, S. H.; Abel, I.

    1984-01-01

    A review of analytical methods and associated tools for active controls analysis and design problems is presented. Approaches employed to develop mathematical models suitable for control system analysis and/or design are discussed. Significant efforts have been expended to develop tools to generate the models from the standpoint of control system designers' needs and develop the tools necessary to analyze and design active control systems. Representative examples of these tools are discussed. Examples where results from the methods and tools have been compared with experimental data are also presented. Finally, a perspective on future trends in analysis and design methods is presented.

  9. Some experiences with active control of aeroelastic response

    NASA Technical Reports Server (NTRS)

    Newsom, J. R.; Abel, I.

    1981-01-01

    Flight and wind tunnel tests were conducted and multidiscipline computer programs were developed as part of investigations of active control technology conducted at the NASA Langley Research Center. Unsteady aerodynamics approximation, optimal control theory, optimal controller design, and the Delta wing and DC-10 models are described. The drones for aerodynamics and structural testing (DAST program) for evaluating procedures for aerodynamic loads prediction and the design of active control systems on wings with significant aeroelastic effects is described as well as the DAST model used in the wind tunnel tests.

  10. Partially Nested Randomized Controlled Trials in Education Research: A Guide to Design and Analysis. NCER 2014-2000

    ERIC Educational Resources Information Center

    Lohr, Sharon; Schochet, Peter Z.; Sanders, Elizabeth

    2014-01-01

    Suppose an education researcher wants to test the impact of a high school drop-out prevention intervention in which at-risk students attend classes to receive intensive summer school instruction. The district will allow the researcher to randomly assign students to the treatment classes or to the control group. Half of the students (the treatment…

  11. METHODS DEVELOPMENT FOR ASSESSING AIR POLLUTION CONTROL BENEFITS. VOLUME IV. STUDIES ON PARTIAL EQUILIBRIUM APPROACHES TO VALUATION OF ENVIRONMENTAL AMENITIES

    EPA Science Inventory

    The research presented in this volume of a five volume study of the economic benefits of air pollution control explores various facets of the two central project objectives that have not been given adequate attention in the previous volumes. The valuations developed in these prev...

  12. Partially resistant Cucurbita pepo showed late onset of the Zucchini yellow mosaic virus infection due to rapid activation of defense mechanisms as compared to susceptible cultivar

    PubMed Central

    Nováková, Slavomíra; Flores-Ramírez, Gabriela; Glasa, Miroslav; Danchenko, Maksym; Fiala, Roderik; Skultety, Ludovit

    2015-01-01

    Zucchini yellow mosaic virus (ZYMV) is an emerging viral pathogen in cucurbit-growing areas wordwide. Infection causes significant yield losses in several species of the family Cucurbitaceae. To identify proteins potentially involved with resistance toward infection by the severe ZYMV-H isolate, two Cucurbita pepo cultivars (Zelena susceptible and Jaguar partially resistant) were analyzed using a two-dimensional gel electrophoresis-based proteomic approach. Initial symptoms on leaves (clearing veins) developed 6–7 days post-inoculation (dpi) in the susceptible C. pepo cv. Zelena. In contrast, similar symptoms appeared on the leaves of partially resistant C. pepo cv. Jaguar only after 15 dpi. This finding was confirmed by immune-blot analysis which showed higher levels of viral proteins at 6 dpi in the susceptible cultivar. Leaf proteome analyses revealed 28 and 31 spots differentially abundant between cultivars at 6 and 15 dpi, respectively. The variance early in infection can be attributed to a rapid activation of proteins involved with redox homeostasis in the partially resistant cultivar. Changes in the proteome of the susceptible cultivar are related to the cytoskeleton and photosynthesis. PMID:25972878

  13. Partially resistant Cucurbita pepo showed late onset of the Zucchini yellow mosaic virus infection due to rapid activation of defense mechanisms as compared to susceptible cultivar.

    PubMed

    Nováková, Slavomíra; Flores-Ramírez, Gabriela; Glasa, Miroslav; Danchenko, Maksym; Fiala, Roderik; Skultety, Ludovit

    2015-01-01

    Zucchini yellow mosaic virus (ZYMV) is an emerging viral pathogen in cucurbit-growing areas wordwide. Infection causes significant yield losses in several species of the family Cucurbitaceae. To identify proteins potentially involved with resistance toward infection by the severe ZYMV-H isolate, two Cucurbita pepo cultivars (Zelena susceptible and Jaguar partially resistant) were analyzed using a two-dimensional gel electrophoresis-based proteomic approach. Initial symptoms on leaves (clearing veins) developed 6-7 days post-inoculation (dpi) in the susceptible C. pepo cv. Zelena. In contrast, similar symptoms appeared on the leaves of partially resistant C. pepo cv. Jaguar only after 15 dpi. This finding was confirmed by immune-blot analysis which showed higher levels of viral proteins at 6 dpi in the susceptible cultivar. Leaf proteome analyses revealed 28 and 31 spots differentially abundant between cultivars at 6 and 15 dpi, respectively. The variance early in infection can be attributed to a rapid activation of proteins involved with redox homeostasis in the partially resistant cultivar. Changes in the proteome of the susceptible cultivar are related to the cytoskeleton and photosynthesis. PMID:25972878

  14. Active control of combustion instabilities in low NO{sub x} gas turbines

    SciTech Connect

    Zinn, B.T.; Neumeier, Y.

    1995-10-01

    This 3-year research program was initiated in September, 1995, to investigate active control of detrimental combustion instabilities in low NO{sub x} gas turbines (LNGT), which burn natural gas in a lean premixed mode to reduce NO{sub x} emissions. The program will investigate the mechanisms that drive these instabilities. Furthermore, it will study active control systems (ACS) that can effectively prevent the onset of such instabilities and/or reduce their amplitudes to acceptable levels. An understanding of the driving mechanisms will not only guide the development of effective ACS for LNGT but may also lead to combustor design changes (i.e., passive control) that will fully or partially resolve the problem. Initial attempts to stabilize combustors (i.e., chemical rockets) by ACS were reported more than 40 years ago, but were unsuccessful due to lack of adequate sensors, electronics, and actuators for performing the needed control actions. Progress made in recent years in sensor and actuator technology, electronics, and control theory has rekindled interest in developing ACS for unstable combustors. While initial efforts in this area, which focused on active control of instabilities in air breathing combustors, have demonstrated the considerable potential of active control, they have also indicated that more effective observers, controllers, and actuators are needed for practical applications. Considerable progress has been made in the observer and actuator areas by the principal investigators of this program during the past 2 years under an AFOSR program. The developed observer is based upon wavelets theory, and can identify the amplitudes, frequencies, and phases of the five most dominant combustor modes in (virtually) real time. The developed actuator is a fuel injector that uses a novel magneto-strictive material to modulate the fuel flow rate into the combustor.

  15. ACTIVELY CONTROLLED VORTEX DISPOSAL SYSTEM FOR SLUDGE WASTES

    EPA Science Inventory

    The development of an advanced sludge treatment concept is under way for applications to sludge wastes. The concept integrates primary treatment of sludge in an advanced vortex containment combustor (VCC) with subsequent post treatment in an actively controlled acoustic afterburn...

  16. ACTIVELY CONTROLLED VORTEX DISPOSAL SYSTEM FOR SLUDGE WASTES

    EPA Science Inventory

    The development of an advanced sludge treatment concept is underway for applications to sludge wastes. The concept integrates primary treatment of sludge in an advanced vortex containment combustor (VCC) with subsequent post treatment in an actively controlled acoustic afterburne...

  17. Application of smart materials to helicopter rotor active control

    NASA Astrophysics Data System (ADS)

    Straub, Friedrich K.; Ealey, Mark A.; Schetky, Lawrence M.

    1997-05-01

    Helicopter design is limited by the compromise inherent in meeting hover and forward flight requirements, and the unsteady environment encountered in forward flight. Active control of helicopter rotors using smart material, in-blade actuation can overcome these barriers and provide substantial reductions in noise and vibrations and improved performance. The present study covers the blade/actuator integration and actuator development for a full scale system to demonstrate active control of noise and vibrations as well as inflight blade tracking on the MD Explorer helicopter. A piezoelectric multilayer stack actuator, driving a trailing edge flap, is used for active control. A shape memory alloy torsion actuator, driving a trailing edge trim tab, is used for inflight tracking. Overall, this DARPA sponsored program entails the design, development, and fabrication of the full scale active control rotor system. If successful, an entry in the NASA Ames 40 X 80 foot wind tunnel and flight tests are planned for a follow on program.

  18. SLUDGE COMBUSTOR USING SWIRL AND ACTIVE COMBUSTION CONTROL

    EPA Science Inventory

    A research program directed at developing technology for compact shipboard incinerators for sludges is described. The concept utilizes previously developed Vortex Containment Combustor (VCC) as a primary unit with an active combustion control afterburner (AB). The overall power s...

  19. Recent results on structural control of an active precision structure

    NASA Technical Reports Server (NTRS)

    Chu, C. C.; Fanson, J. L.; Smith, R. S.

    1991-01-01

    This paper describes recent results in structural control of an active precision truss structure at JPL. The goal is to develop practical control methodology and to apply to active truss structures intended for high precision space-based optics applications. The active structure considered incorporates piezoelectric active members which apply control forces internal to the structure and thereby improve the structure's dimensional stability. Two approaches to structural control system design were investigated. The first approach uses only noncollocated measurements of acceleration at the location of a simulated optical component to achieve structural stabilization. The second approach is essentially the same as the first one except that a viscous damper was used in place of a truss member on the structure to improve the dampings of selected flexible modes. The corresponding experimental closed-loop results are presented in this paper.

  20. DESIGN PROCEDURES FOR DISSOLVED OXYGEN CONTROL OF ACTIVATED SLUDGE PROCESSES

    EPA Science Inventory

    This report presents design procedures and guidelines for the selection of aeration equipment and dissolved (DO) control systems for activated sludge treatment plants. Aeration methods, equipment and application techniques are examined and selection procedures offered. Various DO...

  1. Antimicrobial activity and partial characterization of bacteriocin-like inhibitory substances produced by Lactobacillus spp. isolated from artisanal Mexican cheese.

    PubMed

    Heredia-Castro, Priscilia Y; Méndez-Romero, José I; Hernández-Mendoza, Adrián; Acedo-Félix, Evelia; González-Córdova, Aarón F; Vallejo-Cordoba, Belinda

    2015-12-01

    Lactobacillus spp. from Mexican Cocido cheese were shown to produce bacteriocin-like substances (BLS) active against Staphylococcus aureus,Listeria innocua,Escherichia coli, andSalmonella typhimurium by using the disk diffusion method. Crude extracts of Lactobacillus fermentum showed strong inhibitory activity against Staph. aureus, L. innocua, E. coli, and Salmonella cholerae. Complete inactivation of antimicrobial activity was observed after treatment of crude extracts with proteinase K, pronase, papain, trypsin, and lysozyme, confirming their proteinaceous nature. However, antimicrobial activity was partly lost for some of the crude extracts when treated with α-amylase, indicating that carbohydrate moieties were involved. The antimicrobial activity of the crude extracts was stable at 65°C for 30min over a wide pH range (2-8), and addition of potassium chloride, sodium citrate, ethanol, and butanol did not affect antibacterial activity. However, antimicrobial activity was lost after heating at 121°C for 15min, addition of methanol or Tween 80. Fourteen out of 18 Lactobacillus spp. showed antimicrobial activity against different test microorganisms, and 12 presented bacteriocin-like substances. Generation time and growth rate parameters indicated that the antimicrobial activity of crude extracts from 3 different strains was effective against the 4 indicator microorganisms. One of the crude extracts showed inhibition not only against gram-positive but also against gram-negative bacteria. Bacteriocin-like substances produced by this specific Lactobacillus strain showed potential for application as a food biopreservative. PMID:26476937

  2. 75 FR 48644 - Certain Activated Carbon From the People's Republic of China: Notice of Partial Rescission of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-08-11

    ... Reviews, 75 FR 29976-29980 (May 28, 2010) (``Initiation''). On June 15, 2010, Calgon Carbon Corporation... Limited; Longyan Wanan Activated Carbon; Nanjing Mulinsen Charcoal; Nantong Ameriasia Advanced...

  3. Control of ankle extensor muscle activity in walking cats.

    PubMed

    Hatz, Kathrin; Mombaur, Katja; Donelan, J Maxwell

    2012-11-01

    Our objective was to gain insight into the relative importance of feedforward control and different proprioceptive feedback pathways to ongoing ankle extensor activity during walking in the conscious cat. We asked whether the modulation of stance phase muscle activity is due primarily to proprioceptive feedback and whether the same proprioceptive gains and feedforward commands can automatically generate the muscle activity required for changes in walking slope. To test these hypotheses, we analyzed previously collected muscle activity and mechanics data from cats with an isolated medial gastrocnemius muscle walking along a sloped pegway. Models of proprioceptor dynamics predicted afferent activity from the measured muscle mechanics. We modeled muscle activity as the weighted sum of the activity predicted from the different proprioceptive pathways and a simple model of central drive. We determined the unknown model parameters using optimization procedures that minimized the error between the predicted and measured muscle activity. We found that the modulation of muscle activity within the stance phase and across walking slopes is indeed well described by neural control that employs constant central drive and constant proprioceptive feedback gains. Furthermore, it is force feedback from Ib afferents that is primarily responsible for modulating muscle activity; group II afferent feedback makes a small contribution to tonic activity, and Ia afferent feedback makes no contribution. Force feedback combined with tonic central drive appears to provide a simple control mechanism for automatically compensating for changes in terrain without requiring different commands from the brain or even modification of central nervous system gains. PMID:22933727

  4. The effect of various atomic partial charge schemes to elucidate consensus activity-correlating molecular regions: a test case of diverse QSAR models.

    PubMed

    Kumar, Sivakumar Prasanth; Jha, Prakash C; Jasrai, Yogesh T; Pandya, Himanshu A

    2016-03-01

    The estimation of atomic partial charges of the small molecules to calculate molecular interaction fields (MIFs) is an important process in field-based quantitative structure-activity relationship (QSAR). Several studies showed the influence of partial charge schemes that drastically affects the prediction accuracy of the QSAR model and focused on the selection of appropriate charge models that provide highest cross-validated correlation coefficient ([Formula: see text] or q(2)) to explain the variation in chemical structures against biological endpoints. This study shift this focus in a direction to understand the molecular regions deemed to explain SAR in various charge models and recognize a consensus picture of activity-correlating molecular regions. We selected eleven diverse dataset and developed MIF-based QSAR models using various charge schemes including Gasteiger-Marsili, Del Re, Merck Molecular Force Field, Hückel, Gasteiger-Hückel, and Pullman. The generalized resultant QSAR models were then compared with Open3DQSAR model to interpret the MIF descriptors decisively. We suggest the regions of activity contribution or optimization can be effectively determined by studying various charge-based models to understand SAR precisely. PMID:25997097

  5. Piezoelectric pushers for active vibration control of rotating machinery

    NASA Technical Reports Server (NTRS)

    Palazzolo, Alan B.; Kascak, Albert F.

    1988-01-01

    The active control of rotordynamic vibrations and stability by magnetic bearings and electromagnetic shakers have been discussed extensively in the literature. These devices, though effective, are usually large in volume and add significant weight to the stator. The use of piezoelectric pushers may provide similar degrees of effectiveness in light, compact packages. Tests are currently being conducted with piezoelectric pusher-based active vibration control. Results from tests performed on NASA test rigs as preliminary verification of the related theory are presented.

  6. Robust control design techniques for active flutter suppression

    NASA Technical Reports Server (NTRS)

    Ozbay, Hitay; Bachmann, Glen R.

    1994-01-01

    In this paper, an active flutter suppression problem is studied for a thin airfoil in unsteady aerodynamics. The mathematical model of this system is infinite dimensional because of Theodorsen's function which is irrational. Several second order approximations of Theodorsen's function are compared. A finite dimensional model is obtained from such an approximation. We use H infinity control techniques to find a robustly stabilizing controller for active flutter suppression.

  7. Active vibration control using mechanical and electrical analogies

    NASA Astrophysics Data System (ADS)

    Torres-Perez, A.; Hassan, A.; Kaczmarczyk, S.; Picton, P.

    2016-05-01

    Mechanical-electrical analogous circuit models are widely used in electromechanical system design as they represent the function of a coupled electrical and mechanical system using an equivalent electrical system. This research uses electrical circuits to establish a discussion of simple active vibration control principles using two scenarios: an active vibration isolation system and an active dynamic vibration absorber (DVA) using a voice coil motor (VCM) actuator. Active control laws such as gain scheduling are intuitively explained using circuit analysis techniques. Active vibration control approaches are typically constraint by electrical power requirements. The electrical analogous is a fast approach for specifying power requirements on the experimental test platform which is based on a vibration shaker that provides the based excitation required for the single Degree- of-Freedom (1DoF) vibration model under study.

  8. Active elastic metamaterials for subwavelength wave propagation control

    NASA Astrophysics Data System (ADS)

    Chen, Y. Y.; Huang, G. L.

    2015-06-01

    Recent research activities in elastic metamaterials demonstrate a significant potential for subwavelength wave propagation control owing to their interior locally resonant mechanism. The growing technological developments in electro/magnetomechanical couplings of smart materials have introduced a controlling degree of freedom for passive elastic metamaterials. Active elastic metamaterials could allow for a fine control of material physical behavior and thereby induce new functional properties that cannot be produced by passive approaches. In this paper, two types of active elastic metamaterials with shunted piezoelectric materials and electrorheological elastomers are proposed. Theoretical analyses and numerical validations of the active elastic metamaterials with detailed microstructures are presented for designing adaptive applications in band gap structures and extraordinary waveguides. The active elastic metamaterial could provide a new design methodology for adaptive wave filters, high signal-to-noise sensors, and structural health monitoring applications.

  9. Acoustic Aspects of Active-Twist Rotor Control

    NASA Technical Reports Server (NTRS)

    Booth, Earl R., Jr.; Wilbur, Matthew L.

    2002-01-01

    The use of an Active Twist Rotor system to provide both vibration reduction and performance enhancement has been explored in recent analytical and experimental studies. Effects of active-twist control on rotor noise, however, had not been determined. During a recent wind tunnel test of an active-twist rotor system, a set of acoustic measurements were obtained to assess the effects of active-twist control on noise produced by the rotor, especially blade-vortex interaction (BVI) noise. It was found that for rotor operating conditions where BVI noise is dominant, active-twist control provided a reduction in BVI noise level. This BVI noise reduction was almost, but not quite, as large as that obtained in a similar test using HHC. However, vibration levels were usually adversely affected at operating conditions favoring minimum BVI noise. Conversely, operating conditions favoring minimum vibration levels affected BVI noise levels, but not always adversely.

  10. Practical engineering: control of active systems using the stagnation temperature

    SciTech Connect

    Lunde, P.J.

    1982-04-01

    Solar active systems with flat plate collectors are discussed with reference to the temperature at which the system should be activated. It is concluded that the system should be activated when the stagnation temperature (temperature under the absorber plate when no fluid is circulating) equals the temperature of the fluid in storage. A thermistor Wheatstone bridge control system is described which will eliminate pump relay chatter and the permissible control differential is calculated from the collector efficiency curve. To avoid dedication of an entire collector to house the control system, a method is described for determining the stagnation temperature using a portion of an active collector. For an active solar hot water system, a calculation is carried out to show that a 2/sup 0/F temperature differential (stagnation temperature-storage temperature) is satisfactory. (MJJ)

  11. Controlling neural activity in Caenorhabditis elegans to evoke chemotactic behavior

    NASA Astrophysics Data System (ADS)

    Kocabas, Askin; Shen, Ching-Han; Guo, Zengcai V.; Ramanathan, Sharad

    2013-03-01

    Animals locate and track chemoattractive gradients in the environment to find food. With its simple nervous system, Caenorhabditis elegans is a good model system in which to understand how the dynamics of neural activity control this search behavior. To understand how the activity in its interneurons coordinate different motor programs to lead the animal to food, here we used optogenetics and new optical tools to manipulate neural activity directly in freely moving animals to evoke chemotactic behavior. By deducing the classes of activity patterns triggered during chemotaxis and exciting individual neurons with these patterns, we identified interneurons that control the essential locomotory programs for this behavior. Notably, we discovered that controlling the dynamics of activity in just one interneuron pair was sufficient to force the animal to locate, turn towards and track virtual light gradients.

  12. Active control of the resistive wall mode with power saturation

    SciTech Connect

    Li Li; Liu Yue; Liu Yueqiang

    2012-01-15

    An analytic model of non-linear feedback stabilization of the resistive wall mode is presented. The non-linearity comes from either the current or the voltage saturation of the control coil power supply. For the so-called flux-to-current control, the current saturation of active coils always results in the loss of control. On the contrary, the flux-to-voltage control scheme tolerates certain degree of the voltage saturation. The minimal voltage limit is calculated, below which the control will be lost.

  13. Semi-active control of seat suspension with MR damper

    NASA Astrophysics Data System (ADS)

    Yao, H. J.; Fu, J.; Yu, M.; Peng, Y. X.

    2013-02-01

    The vibration control of a seat suspension system with magnetorheological (MR) damper is investigated in this study. Firstly, a dynamical model of the seat suspension system with parameter uncertainties (such as mass, stiffness, damping) and actuator saturation is established. Secondly, based on Lyapunov functional theory and considering constraint conditions for damping force, the semi-active controller is designed, and the controller parameters are derived in terms of linear matrix inequalities (LMIs), which guarantees performance index. Finally, compared control strategy and the passive, skyhook control strategy, the simulation results in time and frequency domains demonstrate the proposed approach can achieve better vertical acceleration attenuation for the seat suspension system and improve ride comfort.

  14. New design deforming controlling system of the active stressed lap

    NASA Astrophysics Data System (ADS)

    Ying, Li; Wang, Daxing

    2008-07-01

    A 450mm diameter active stressed lap has been developed in NIAOT by 2003. We design a new lap in 2007. This paper puts on emphases on introducing the new deforming control system of the lap. Aiming at the control characteristic of the lap, a new kind of digital deforming controller is designed. The controller consists of 3 parts: computer signal disposing, motor driving and force sensor signal disposing. Intelligent numeral PID method is applied in the controller instead of traditional PID. In the end, the result of new deformation are given.

  15. Applications of active adaptive noise control to jet engines

    NASA Technical Reports Server (NTRS)

    Shoureshi, Rahmat; Brackney, Larry

    1993-01-01

    During phase 2 research on the application of active noise control to jet engines, the development of multiple-input/multiple-output (MIMO) active adaptive noise control algorithms and acoustic/controls models for turbofan engines were considered. Specific goals for this research phase included: (1) implementation of a MIMO adaptive minimum variance active noise controller; and (2) turbofan engine model development. A minimum variance control law for adaptive active noise control has been developed, simulated, and implemented for single-input/single-output (SISO) systems. Since acoustic systems tend to be distributed, multiple sensors, and actuators are more appropriate. As such, the SISO minimum variance controller was extended to the MIMO case. Simulation and experimental results are presented. A state-space model of a simplified gas turbine engine is developed using the bond graph technique. The model retains important system behavior, yet is of low enough order to be useful for controller design. Expansion of the model to include multiple stages and spools is also discussed.

  16. Electromechanical Simulation of Actively Controlled Rotordynamic Systems with Piezoelectric Actuators

    NASA Technical Reports Server (NTRS)

    Lin, Reng Rong; Palazzolo, A. B.; Kascak, A. F.; Montague, G.

    1991-01-01

    Theories and tests for incorporating piezoelectric pushers as actuator devices for active vibration control are discussed. It started from a simple model with the assumption of ideal pusher characteristics and progressed to electromechanical models with nonideal pushers. Effects on system stability due to the nonideal characteristics of piezoelectric pushers and other elements in the control loop were investigated.

  17. Advanced aerodynamics and active controls. Selected NASA research

    NASA Technical Reports Server (NTRS)

    1981-01-01

    Aerodynamic and active control concepts for application to commercial transport aircraft are discussed. Selected topics include in flight direct strike lightning research, triply redundant digital fly by wire control systems, tail configurations, winglets, and the drones for aerodynamic and structural testing (DAST) program.

  18. Active Flow Control Strategies Using Surface Pressure Measurements

    NASA Technical Reports Server (NTRS)

    Kumar, Vikas; Alvi, Farrukh S.

    2010-01-01

    Evaluate the efficacy of Microjets Can we eliminate/minimize flow separation? Is the flow unsteadiness reduced? Guidelines for an active control Search for an appropriate sensor. Examine for means to develop a flow model for identifying the state of flow over the surface Guidelines toward future development of a Simple and Robust control methodology

  19. Operational Control Procedures for the Activated Sludge Process: Appendix.

    ERIC Educational Resources Information Center

    West, Alfred W.

    This document is the appendix for a series of documents developed by the National Training and Operational Technology Center describing operational control procedures for the activated sludge process used in wastewater treatment. Categories discussed include: control test data, trend charts, moving averages, semi-logarithmic plots, probability…

  20. Dynamic-Loads Analysis of Flexible Aircraft With Active Controls

    NASA Technical Reports Server (NTRS)

    Perry, B. I.; Durling, B. J.

    1982-01-01

    Integrated system of stand-along computer programs, DYLOFLEX, analyzes dynamic loads on flexible aircraft with active controls. DYLOFLEX capabilities include calculating dynamic loads due to continuous atmospheric turbulence, discrete gusts, and discrete control inputs. Each of the eight individual DYLOFLEX programs may be used alone or in conjunction with other DYLOFLEX programs.

  1. An electric control for an electrohydraulic active control aircraft landing gear

    NASA Technical Reports Server (NTRS)

    Ross, I.; Edson, R.

    1979-01-01

    An electronic controller for an electrohydraulic active control aircraft landing gear was developed. Drop tests of a modified gear from a 2722 Kg (6000 lbm) class of airplane were conducted to illustrate controller performance. The results indicate that the active gear effects a force reduction, relative to that of the passive gear, from 9 to 31 percent depending on the aircraft sink speed and the static gear pressure.

  2. Active following fuzzy output feedback sliding mode control of real-vehicle semi-active suspensions

    NASA Astrophysics Data System (ADS)

    Liu, H.; Nonami, K.; Hagiwara, T.

    2008-07-01

    Many semi-active suspension systems have been investigated in various literatures in order to achieve lower energy consumption and as good performance as full-active suspension systems. Full-active suspension systems can achieve a good ride quality by actuators; however, their implementation equipments are expensive. The full-active suspensions are perfect from the point of view of control; hence, semi-active control laws with performance similar to full-active controls have attracted the engineering community for their ease and lower cost of implementation. This paper presents a new active following fuzzy output feedback sliding mode control for a real-vehicle semi-active suspension system. The performance of the proposed controller has been verified by comparing it with passive control and also with the full-active target semi-active approximation control method. In the experiment, it was shown that the proposed method has the effectiveness in stabilizing heave, roll and pitch movement of the car body.

  3. Active vibration control techniques for flexible space structures

    NASA Technical Reports Server (NTRS)

    Parlos, Alexander G.; Jayasuriya, Suhada

    1990-01-01

    Two proposed control system design techniques for active vibration control in flexible space structures are detailed. Control issues relevant only to flexible-body dynamics are addressed, whereas no attempt was made to integrate the flexible and rigid-body spacecraft dynamics. Both of the proposed approaches revealed encouraging results; however, further investigation of the interaction of the flexible and rigid-body dynamics is warranted.

  4. Cystometric parameters and the activity of signaling proteins in association with the compensation or decompensation of bladder function in an animal experimental model of partial bladder outlet obstruction.

    PubMed

    Choi, Bo-Hwa; Jin, Long-Hu; Kim, Khae-Hawn; Kang, Sung-An; Kang, Ju-Hee; Yoon, Sang-Min; Park, Chang-Shin; Lee, Tack

    2013-12-01

    We conducted this study to determine whether the degree of detrusor contractility is associated with the compensation or decompensation of bladder function depending on the residual volume (RV) during the first two weeks after the onset of partial bladder outlet obstruction (BOO). Moreover, we also examined whether the degree of the phosphorylation and expression of signaling proteins [AMP-activated kinase (AMPK), extracellular signal‑regulated protein kinases 1 and 2 (ERK1/2) and protein kinase C (PKC)] is associated with the prevalence of compensation or decompensation of bladder function. Twenty-seven female Sprague-Dawley (SD) rats were randomly assigned to either the sham-operated group (n=7) or the group with partial bladder outlet obstruction (BOO) (n=20). We then measured cystometric parameters from three reproducible micturition cycles and averaged the results for a comparison between the two groups. Based on a cut-off value of a mean RV% of 25%, we subdivided our experimental animals into two subgroups: the subgroup with bladder compensation (mean RV%, <25%) and the subgroup with bladder decompensation (mean RV%, >25%). Our results indicated that the degree of detrusor overactivity (DO) was associated with the compensation or decompensation of bladder function depending on the RV during the first two weeks after the onset of BOO in an animal experimental model of partial BOO. Moreover, we also demonstrate that AMPK and ERK1/2 are involved in the compensation or decompensation of bladder function. Furthermore, our results suggest that PKC is not involved in two-phase bladder contraction. Alterations in the activities of signaling proteins, such as AMPK and ERK1/2 may prove to be helpful in the treatment of patients with voiding difficulty. PMID:24085268

  5. Remote Control of T Cell Activation Using Magnetic Janus Particles.

    PubMed

    Lee, Kwahun; Yi, Yi; Yu, Yan

    2016-06-20

    We report a strategy for using magnetic Janus microparticles to control the stimulation of T cell signaling with single-cell precision. To achieve this, we designed Janus particles that are magnetically responsive on one hemisphere and stimulatory to T cells on the other side. By manipulating the rotation and locomotion of Janus particles under an external magnetic field, we could control the orientation of the particle-cell recognition and thereby the initiation of T cell activation. This study demonstrates a step towards employing anisotropic material properties of Janus particles to control single-cell activities without the need of complex magnetic manipulation devices. PMID:27144475

  6. Impact of active controls technology on structural integrity

    NASA Technical Reports Server (NTRS)

    Noll, Thomas; Austin, Edward; Donley, Shawn; Graham, George; Harris, Terry

    1991-01-01

    This paper summarizes the findings of The Technical Cooperation Program to assess the impact of active controls technology on the structural integrity of aeronautical vehicles and to evaluate the present state-of-the-art for predicting the loads caused by a flight-control system modification and the resulting change in the fatigue life of the flight vehicle. The potential for active controls to adversely affect structural integrity is described, and load predictions obtained using two state-of-the-art analytical methods are given.

  7. Active Noise Control Experiments using Sound Energy Flu

    NASA Astrophysics Data System (ADS)

    Krause, Uli

    2015-03-01

    This paper reports on the latest results concerning the active noise control approach using net flow of acoustic energy. The test set-up consists of two loudspeakers simulating the engine noise and two smaller loudspeakers which belong to the active noise system. The system is completed by two acceleration sensors and one microphone per loudspeaker. The microphones are located in the near sound field of the loudspeakers. The control algorithm including the update equation of the feed-forward controller is introduced. Numerical simulations are performed with a comparison to a state of the art method minimising the radiated sound power. The proposed approach is experimentally validated.

  8. Selected advanced aerodynamic and active control concepts development

    NASA Technical Reports Server (NTRS)

    1980-01-01

    A summary is presented of results obtained during analysis, design and test activities on six selected technical tasks directed at exploratory improvement of fuel efficiency for new and derivative transports. The work included investigations into the potential offered by natural laminar flow, improved surface coatings and advanced high lift concepts. Similar investigations covering optimum low-energy flight path control, integrated application of active controls and evaluation of primary flight control systems reliability and maintenance are also summarized. Recommendations are included for future work needed to exploit potential advancements.

  9. Control surface spanwise placement in active flutter suppression systems

    NASA Technical Reports Server (NTRS)

    Nissim, E.; Burken, John J.

    1988-01-01

    A method is developed that determines the placement of an active control surface for maximum effectiveness in suppressing flutter. No specific control law is required by this method which is based on the aerodynamic energy concept. It is argued that the spanwise placement of the active controls should coincide with the locations where maximum energy per unit span is fed into the system. The method enables one to determine the distribution, over the different surfaces of the aircraft, of the energy input into the system as a result of the unstable fluttering mode. The method is illustrated using three numerical examples.

  10. Fuel conservation through active control of rotor clearances

    NASA Technical Reports Server (NTRS)

    Beitler, R. S.; Saunders, A. A.; Wanger, R. P.

    1980-01-01

    Under the NASA-sponsored Energy Efficient Engine (EEE) Project, technology is being developed which will significantly reduce the fuel consumption of turbofan engines for subsonic transport aircraft. One technology concept being pursued is active control of rotor tip clearances. Attention is given to rotor tip clearance considerations and an overview of preliminary study results as well as the General Electric EEE clearance control approach is presented. Finally, potential fuel savings with active control of rotor clearances for a typical EEE mission are predicted.

  11. The Role of Water Activity and Capillarity in Partially Saturated Porous Media at Geologic CO2 Storage Sites

    NASA Astrophysics Data System (ADS)

    Heath, J. E.; Bryan, C. R.; Matteo, E. N.; Dewers, T. A.; Wang, Y.

    2012-12-01

    The activity of water in supercritical CO2 may affect performance of geologic CO2 storage, including CO2 injectivity, and shrink-swell properties and sealing efficiency of clayey caprocks. We present a pore-scale unit cell model of water film adsorption and capillary condensation as an explicit function of water activity in supercritical CO2. This model estimates water film configuration in slit to other pore shapes with edges and corners. With the model, we investigate water saturation in porous media in mineral-CO2-water systems under different water activities. Maximum water activities in equilibrium with an aqueous phase are significantly less than unity due to dissolution of CO2 in water (i.e., the mole fraction of water in the aqueous phase is much less than one) and variable dissolved salt concentration. The unit cell approach is used to upscale from the single pore to the core-sample-scale, giving saturation curves as a function of water activity in the supercritical phase and the texture of the porous media. We evaluate the model and the importance of water activity through ongoing small angle neutron scattering experiments and other column experiments, which investigate shrink-swell properties and capillarity under realistic in situ stresses. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

  12. Flutter prediction for a wing with active aileron control

    NASA Technical Reports Server (NTRS)

    Penning, K.; Sandlin, D. R.

    1983-01-01

    A method for predicting the vibrational stability of an aircraft with an analog active aileron flutter suppression system (FSS) is expained. Active aileron refers to the use of an active control system connected to the aileron to damp vibrations. Wing vibrations are sensed by accelerometers and the information is used to deflect the aileron. Aerodynamic force caused by the aileron deflection oppose wing vibrations and effectively add additional damping to the system.

  13. Active-Twist Rotor Control Applications for UAVs

    NASA Technical Reports Server (NTRS)

    Wilbur, Matthew L.; Wilkie, W. Keats

    2004-01-01

    The current state-of-the-art in active-twist rotor control is discussed using representative examples from analytical and experimental studies, and the application to rotary-wing UAVs is considered. Topics include vibration and noise reduction, rotor performance improvement, active blade tracking, stability augmentation, and rotor blade de-icing. A review of the current status of piezoelectric fiber composite actuator technology, the class of piezoelectric actuators implemented in active-twist rotor systems, is included.

  14. Active structural control by fuzzy logic rules: An introduction

    SciTech Connect

    Tang, Yu; Wu, Kung C.

    1996-12-31

    A zeroth level introduction to fuzzy logic control applied to the active structural control to reduce the dynamic response of structures subjected to earthquake excitations is presented. It is hoped that this presentation will increase the attractiveness of the methodology to structural engineers in research as well as in practice. The basic concept of the fuzzy logic control are explained by examples and by diagrams with a minimum of mathematics. The effectiveness and simplicity of the fuzzy logic control is demonstrated by a numerical example in which the response of a single- degree-of-freedom system subjected to earthquake excitations is controlled by making use of the fuzzy logic controller. In the example, the fuzzy rules are first learned from the results obtained from linear control theory; then they are fine tuned to improve their performance. It is shown that the performance of fuzzy logic control surpasses that of the linear control theory. The paper shows that linear control theory provides experience for fuzzy logic control, and fuzzy logic control can provide better performance; therefore, two controllers complement each other.

  15. Active structural control by fuzzy logic rules: An introduction

    SciTech Connect

    Tang, Y.

    1995-07-01

    An introduction to fuzzy logic control applied to the active structural control to reduce the dynamic response of structures subjected to earthquake excitations is presented. It is hoped that this presentation will increase the attractiveness of the methodology to structural engineers in research as well as in practice. The basic concept of the fuzzy logic control are explained by examples and by diagrams with a minimum of mathematics. The effectiveness and simplicity of the fuzzy logic control is demonstrated by a numerical example in which the response of a single-degree-of-freedom system subjected to earthquake excitations is controlled by making use of the fuzzy logic controller. In the example, the fuzzy rules are first learned from the results obtained from linear control theory; then they are fine tuned to improve their performance. It is shown that the performance of fuzzy logic control surpasses that of the linear control theory. The paper shows that linear control theory provides experience for fuzzy logic control, and fuzzy logic control can provide better performance; therefore, two controllers complement each other.

  16. Partially integrated exhaust manifold

    DOEpatents

    Hayman, Alan W; Baker, Rodney E

    2015-01-20

    A partially integrated manifold assembly is disclosed which improves performance, reduces cost and provides efficient packaging of engine components. The partially integrated manifold assembly includes a first leg extending from a first port and terminating at a mounting flange for an exhaust gas control valve. Multiple additional legs (depending on the total number of cylinders) are integrally formed with the cylinder head assembly and extend from the ports of the associated cylinder and terminate at an exit port flange. These additional legs are longer than the first leg such that the exit port flange is spaced apart from the mounting flange. This configuration provides increased packaging space adjacent the first leg for any valving that may be required to control the direction and destination of exhaust flow in recirculation to an EGR valve or downstream to a catalytic converter.

  17. Shape control and compartmentalization in active colloidal cells.

    PubMed

    Spellings, Matthew; Engel, Michael; Klotsa, Daphne; Sabrina, Syeda; Drews, Aaron M; Nguyen, Nguyen H P; Bishop, Kyle J M; Glotzer, Sharon C

    2015-08-25

    Small autonomous machines like biological cells or soft robots can convert energy input into control of function and form. It is desired that this behavior emerges spontaneously and can be easily switched over time. For this purpose we introduce an active matter system that is loosely inspired by biology and which we term an active colloidal cell. The active colloidal cell consists of a boundary and a fluid interior, both of which are built from identical rotating spinners whose activity creates convective flows. Similarly to biological cell motility, which is driven by cytoskeletal components spread throughout the entire volume of the cell, active colloidal cells are characterized by highly distributed energy conversion. We demonstrate that we can control the shape of the active colloidal cell and drive compartmentalization by varying the details of the boundary (hard vs. flexible) and the character of the spinners (passive vs. active). We report buckling of the boundary controlled by the pattern of boundary activity, as well as formation of core-shell and inverted Janus phase-separated configurations within the active cell interior. As the cell size is increased, the inverted Janus configuration spontaneously breaks its mirror symmetry. The result is a bubble-crescent configuration, which alternates between two degenerate states over time and exhibits collective migration of the fluid along the boundary. Our results are obtained using microscopic, non-momentum-conserving Langevin dynamics simulations and verified via a phase-field continuum model coupled to a Navier-Stokes equation. PMID:26253763

  18. Shape control and compartmentalization in active colloidal cells

    PubMed Central

    Spellings, Matthew; Engel, Michael; Klotsa, Daphne; Sabrina, Syeda; Drews, Aaron M.; Nguyen, Nguyen H. P.; Bishop, Kyle J. M.; Glotzer, Sharon C.

    2015-01-01

    Small autonomous machines like biological cells or soft robots can convert energy input into control of function and form. It is desired that this behavior emerges spontaneously and can be easily switched over time. For this purpose we introduce an active matter system that is loosely inspired by biology and which we term an active colloidal cell. The active colloidal cell consists of a boundary and a fluid interior, both of which are built from identical rotating spinners whose activity creates convective flows. Similarly to biological cell motility, which is driven by cytoskeletal components spread throughout the entire volume of the cell, active colloidal cells are characterized by highly distributed energy conversion. We demonstrate that we can control the shape of the active colloidal cell and drive compartmentalization by varying the details of the boundary (hard vs. flexible) and the character of the spinners (passive vs. active). We report buckling of the boundary controlled by the pattern of boundary activity, as well as formation of core–shell and inverted Janus phase-separated configurations within the active cell interior. As the cell size is increased, the inverted Janus configuration spontaneously breaks its mirror symmetry. The result is a bubble–crescent configuration, which alternates between two degenerate states over time and exhibits collective migration of the fluid along the boundary. Our results are obtained using microscopic, non–momentum-conserving Langevin dynamics simulations and verified via a phase-field continuum model coupled to a Navier–Stokes equation. PMID:26253763

  19. Mitigation of chatter instabilities in milling by active structural control

    NASA Astrophysics Data System (ADS)

    Dohner, Jeffrey L.; Lauffer, James P.; Hinnerichs, Terry D.; Shankar, Natarajan; Regelbrugge, Mark; Kwan, Chi-Man; Xu, Roger; Winterbauer, Bill; Bridger, Keith

    2004-01-01

    This paper documents the experimental validation of an active control approach for mitigating chatter in milling. To the authors knowledge, this is the first successful hardware demonstration of this approach. This approach is very different from many existing approaches that avoid instabilities by varying process parameters to seek regions of stability or by altering the regenerative process. In this approach, the stability lobes of the machine and tool are actively raised. This allows for machining at spindle speeds that are more representative of those used in existing machine tools. An active control system was implemented using actuators and sensors surrounding a spindle and tool. Due to the complexity of controlling from a stationary co-ordinate system and sensing from a rotating system, a telemetry system was used to transfer structural vibration data from the tool to a control processor. Closed-loop experiments produced up to an order of magnitude improvement in metal removal rate.

  20. Experimental evaluation of active-member control of precision structures

    NASA Technical Reports Server (NTRS)

    Fanson, James; Blackwood, Gary; Chu, Cheng-Chih

    1989-01-01

    The results of closed loop experiments that use piezoelectric active-members to control the flexible motion of a precision truss structure are described. These experiments are directed toward the development of high-performance structural systems as part of the Control/Structure Interaction (CSI) program at JPL. The focus of CSI activity at JPL is to develop the technology necessary to accurately control both the shape and vibration levels in the precision structures from which proposed large space-based observatories will be built. Structural error budgets for these types of structures will likely be in the sub-micron regime; optical tolerances will be even tighter. In order to achieve system level stability and local positioning at this level, it is generally expected that some form of active control will be required.